From e7f2632a13e527275ed4e382a2729ae29d9d87f6 Mon Sep 17 00:00:00 2001
From: rfraposa <richraposa@gmail.com>
Date: Fri, 8 Apr 2022 15:57:23 -0600
Subject: [PATCH] Added the en/reference folder

---
 .github/workflows/deploy-github.yml           |    1 +
 .gitignore                                    |    1 -
 docs/en/reference/development/_category_.yml  |    8 +
 .../development/adding_test_queries.md        |  157 +
 docs/en/reference/development/architecture.md |  202 +
 docs/en/reference/development/browse-code.md  |   13 +
 .../reference/development/build-cross-arm.md  |   38 +
 .../reference/development/build-cross-osx.md  |   62 +
 .../development/build-cross-riscv.md          |   30 +
 docs/en/reference/development/build-osx.md    |  154 +
 docs/en/reference/development/build.md        |  181 +
 .../development/continuous-integration.md     |  193 +
 docs/en/reference/development/contrib.md      |  107 +
 .../development/developer-instruction.md      |  278 ++
 docs/en/reference/development/style.md        |  832 ++++
 docs/en/reference/development/tests.md        |  297 ++
 docs/en/reference/engines/_category_.yml      |    8 +
 .../engines/database-engines/atomic.md        |   61 +
 .../engines/database-engines/index.md         |   25 +
 .../engines/database-engines/lazy.md          |   16 +
 .../database-engines/materialized-mysql.md    |  290 ++
 .../materialized-postgresql.md                |  279 ++
 .../engines/database-engines/mysql.md         |  151 +
 .../engines/database-engines/postgresql.md    |  139 +
 .../engines/database-engines/replicated.md    |  123 +
 .../engines/database-engines/sqlite.md        |   80 +
 .../reference/engines/table-engines/index.md  |   89 +
 .../integrations/ExternalDistributed.md       |   56 +
 .../integrations/embedded-rocksdb.md          |   84 +
 .../table-engines/integrations/hdfs.md        |  230 +
 .../table-engines/integrations/hive.md        |  410 ++
 .../table-engines/integrations/index.md       |   23 +
 .../table-engines/integrations/jdbc.md        |   95 +
 .../table-engines/integrations/kafka.md       |  198 +
 .../integrations/materialized-postgresql.md   |   59 +
 .../table-engines/integrations/mongodb.md     |   79 +
 .../table-engines/integrations/mysql.md       |  152 +
 .../table-engines/integrations/odbc.md        |  131 +
 .../table-engines/integrations/postgresql.md  |  178 +
 .../table-engines/integrations/rabbitmq.md    |  175 +
 .../engines/table-engines/integrations/s3.md  |  163 +
 .../table-engines/integrations/sqlite.md      |   62 +
 .../engines/table-engines/log-family/index.md |   46 +
 .../engines/table-engines/log-family/log.md   |   15 +
 .../table-engines/log-family/stripelog.md     |   93 +
 .../table-engines/log-family/tinylog.md       |   14 +
 .../mergetree-family/aggregatingmergetree.md  |  104 +
 .../mergetree-family/collapsingmergetree.md   |  307 ++
 .../custom-partitioning-key.md                |  136 +
 .../mergetree-family/graphitemergetree.md     |  260 +
 .../table-engines/mergetree-family/index.md   |   16 +
 .../mergetree-family/mergetree.md             |  953 ++++
 .../mergetree-family/replacingmergetree.md    |   70 +
 .../mergetree-family/replication.md           |  295 ++
 .../mergetree-family/summingmergetree.md      |  140 +
 .../versionedcollapsingmergetree.md           |  237 +
 .../engines/table-engines/special/buffer.md   |   77 +
 .../table-engines/special/dictionary.md       |  101 +
 .../table-engines/special/distributed.md      |  229 +
 .../table-engines/special/external-data.md    |   65 +
 .../engines/table-engines/special/file.md     |   89 +
 .../engines/table-engines/special/generate.md |   59 +
 .../engines/table-engines/special/index.md    |   14 +
 .../engines/table-engines/special/join.md     |  130 +
 .../table-engines/special/materializedview.md |   10 +
 .../engines/table-engines/special/memory.md   |   18 +
 .../engines/table-engines/special/merge.md    |   85 +
 .../engines/table-engines/special/null.md     |   15 +
 .../engines/table-engines/special/set.md      |   23 +
 .../engines/table-engines/special/url.md      |   92 +
 .../engines/table-engines/special/view.md     |   10 +
 .../reference/getting-started/_category_.yml  |    8 +
 .../example-datasets/_category_.yml           |    8 +
 .../example-datasets/amplab-benchmark.md      |  127 +
 .../example-datasets/brown-benchmark.md       |  416 ++
 .../example-datasets/cell-towers.md           |  131 +
 .../example-datasets/criteo.md                |   78 +
 .../example-datasets/github-events.md         |   10 +
 .../getting-started/example-datasets/menus.md |  354 ++
 .../example-datasets/metrica.md               |   78 +
 .../example-datasets/nyc-taxi.md              |  392 ++
 .../example-datasets/ontime.md                |  408 ++
 .../example-datasets/opensky.md               |  420 ++
 .../example-datasets/recipes.md               |  339 ++
 .../example-datasets/star-schema.md           |  371 ++
 .../example-datasets/uk-price-paid.md         |  648 +++
 .../example-datasets/wikistat.md              |   32 +
 docs/en/reference/getting-started/install.md  |  312 ++
 .../reference/getting-started/playground.md   |   46 +
 docs/en/reference/images/column-oriented.gif  |  Bin 0 -> 43771 bytes
 docs/en/reference/images/logo.svg             |    1 +
 docs/en/reference/images/play.png             |  Bin 0 -> 26602 bytes
 docs/en/reference/images/row-oriented.gif     |  Bin 0 -> 39281 bytes
 docs/en/reference/interfaces/cli.md           |  181 +
 docs/en/reference/interfaces/cpp.md           |   10 +
 docs/en/reference/interfaces/formats.md       | 1707 +++++++
 docs/en/reference/interfaces/grpc.md          |   99 +
 docs/en/reference/interfaces/http.md          |  664 +++
 docs/en/reference/interfaces/index.md         |   28 +
 docs/en/reference/interfaces/jdbc.md          |   14 +
 docs/en/reference/interfaces/mysql.md         |   53 +
 docs/en/reference/interfaces/odbc.md          |   12 +
 docs/en/reference/interfaces/tcp.md           |   10 +
 .../third-party/client-libraries.md           |   74 +
 .../reference/interfaces/third-party/gui.md   |  247 +
 .../reference/interfaces/third-party/index.md |   17 +
 .../interfaces/third-party/integrations.md    |  112 +
 .../reference/interfaces/third-party/proxy.md |   44 +
 docs/en/reference/operations/_category_.yml   |    4 +
 docs/en/reference/operations/access-rights.md |  154 +
 docs/en/reference/operations/backup.md        |   41 +
 docs/en/reference/operations/caches.md        |   29 +
 .../reference/operations/clickhouse-keeper.md |  325 ++
 .../operations/configuration-files.md         |  159 +
 .../external-authenticators/index.md          |   16 +
 .../external-authenticators/kerberos.md       |  118 +
 .../external-authenticators/ldap.md           |  182 +
 .../external-authenticators/ssl-x509.md       |   24 +
 docs/en/reference/operations/index.md         |   25 +
 docs/en/reference/operations/monitoring.md    |   44 +
 .../reference/operations/named-collections.md |  230 +
 docs/en/reference/operations/opentelemetry.md |   65 +
 .../optimizing-performance/index.md           |    8 +
 .../sampling-query-profiler.md                |   62 +
 .../reference/operations/performance-test.md  |   83 +
 docs/en/reference/operations/quotas.md        |  120 +
 docs/en/reference/operations/requirements.md  |   59 +
 .../server-configuration-parameters/index.md  |   16 +
 .../settings.md                               | 1630 +++++++
 .../settings/constraints-on-settings.md       |   73 +
 .../en/reference/operations/settings/index.md |   58 +
 .../settings/merge-tree-settings.md           |  383 ++
 .../settings/permissions-for-queries.md       |   59 +
 .../operations/settings/query-complexity.md   |  315 ++
 .../operations/settings/settings-profiles.md  |   80 +
 .../operations/settings/settings-users.md     |  164 +
 .../reference/operations/settings/settings.md | 4232 +++++++++++++++++
 docs/en/reference/operations/ssl-zookeeper.md |   73 +
 docs/en/reference/operations/storing-data.md  |  318 ++
 .../system-tables/asynchronous_metric_log.md  |   39 +
 .../system-tables/asynchronous_metrics.md     |   38 +
 .../operations/system-tables/clusters.md      |   71 +
 .../operations/system-tables/columns.md       |   89 +
 .../operations/system-tables/contributors.md  |   41 +
 .../operations/system-tables/crash-log.md     |   48 +
 .../operations/system-tables/current-roles.md |   11 +
 .../system-tables/data_skipping_indices.md    |   47 +
 .../system-tables/data_type_families.md       |   36 +
 .../operations/system-tables/databases.md     |   37 +
 .../system-tables/detached_parts.md           |   11 +
 .../operations/system-tables/dictionaries.md  |   88 +
 .../operations/system-tables/disks.md         |   27 +
 .../system-tables/distributed_ddl_queue.md    |   64 +
 .../system-tables/distribution_queue.md       |   50 +
 .../operations/system-tables/enabled-roles.md |   12 +
 .../operations/system-tables/errors.md        |   36 +
 .../operations/system-tables/events.md        |   34 +
 .../operations/system-tables/functions.md     |   33 +
 .../operations/system-tables/grants.md        |   24 +
 .../system-tables/graphite_retentions.md      |   17 +
 .../operations/system-tables/index.md         |   74 +
 .../system-tables/information_schema.md       |  210 +
 .../operations/system-tables/licenses.md      |   39 +
 .../system-tables/merge_tree_settings.md      |   54 +
 .../operations/system-tables/merges.md        |   25 +
 .../operations/system-tables/metric_log.md    |   51 +
 .../operations/system-tables/metrics.md       |   41 +
 .../operations/system-tables/mutations.md     |   49 +
 .../operations/system-tables/numbers.md       |   32 +
 .../operations/system-tables/numbers_mt.md    |   30 +
 .../reference/operations/system-tables/one.md |   23 +
 .../system-tables/opentelemetry_span_log.md   |   53 +
 .../operations/system-tables/part_log.md      |   69 +
 .../operations/system-tables/parts.md         |  168 +
 .../operations/system-tables/parts_columns.md |  148 +
 .../operations/system-tables/processes.md     |   61 +
 .../operations/system-tables/query_log.md     |  189 +
 .../system-tables/query_thread_log.md         |  119 +
 .../system-tables/query_views_log.md          |   86 +
 .../operations/system-tables/quota_limits.md  |   21 +
 .../operations/system-tables/quota_usage.md   |   32 +
 .../operations/system-tables/quotas.md        |   28 +
 .../operations/system-tables/quotas_usage.md  |   35 +
 .../operations/system-tables/replicas.md      |  132 +
 .../system-tables/replicated_fetches.md       |   70 +
 .../system-tables/replication_queue.md        |   91 +
 .../operations/system-tables/role-grants.md   |   21 +
 .../operations/system-tables/roles.md         |   15 +
 .../operations/system-tables/row_policies.md  |   34 +
 .../operations/system-tables/session_log.md   |   77 +
 .../operations/system-tables/settings.md      |   53 +
 .../settings_profile_elements.md              |   30 +
 .../system-tables/settings_profiles.md        |   24 +
 .../operations/system-tables/stack_trace.md   |   91 +
 .../system-tables/storage_policies.md         |   17 +
 .../operations/system-tables/table_engines.md |   38 +
 .../operations/system-tables/tables.md        |  125 +
 .../operations/system-tables/text_log.md      |   53 +
 .../operations/system-tables/time_zones.md    |   30 +
 .../operations/system-tables/trace_log.md     |   57 +
 .../operations/system-tables/users.md         |   34 +
 .../operations/system-tables/zookeeper.md     |   75 +
 .../operations/system-tables/zookeeper_log.md |  129 +
 docs/en/reference/operations/tips.md          |  279 ++
 .../reference/operations/troubleshooting.md   |  144 +
 docs/en/reference/operations/update.md        |   32 +
 .../utilities/clickhouse-benchmark.md         |  163 +
 .../utilities/clickhouse-compressor.md        |   28 +
 .../operations/utilities/clickhouse-copier.md |  188 +
 .../operations/utilities/clickhouse-format.md |  109 +
 .../operations/utilities/clickhouse-local.md  |  118 +
 .../utilities/clickhouse-obfuscator.md        |   42 +
 .../reference/operations/utilities/index.md   |   15 +
 .../operations/utilities/odbc-bridge.md       |   38 +
 .../en/reference/sql-reference/_category_.yml |    4 +
 .../aggregate-functions/combinators.md        |  287 ++
 .../aggregate-functions/index.md              |   60 +
 .../parametric-functions.md                   |  766 +++
 .../aggregate-functions/reference/any.md      |   13 +
 .../aggregate-functions/reference/anyheavy.md |   30 +
 .../aggregate-functions/reference/anylast.md  |    8 +
 .../aggregate-functions/reference/argmax.md   |   50 +
 .../aggregate-functions/reference/argmin.md   |   50 +
 .../aggregate-functions/reference/avg.md      |   66 +
 .../reference/avgweighted.md                  |   99 +
 .../reference/categoricalinformationvalue.md  |   13 +
 .../aggregate-functions/reference/corr.md     |   13 +
 .../aggregate-functions/reference/count.md    |   72 +
 .../aggregate-functions/reference/covarpop.md |   13 +
 .../reference/covarsamp.md                    |   13 +
 .../aggregate-functions/reference/deltasum.md |   73 +
 .../reference/deltasumtimestamp.md            |   45 +
 .../aggregate-functions/reference/entropy.md  |   43 +
 .../reference/exponentialmovingaverage.md     |  148 +
 .../reference/grouparray.md                   |   14 +
 .../reference/grouparrayinsertat.md           |   91 +
 .../reference/grouparraymovingavg.md          |   78 +
 .../reference/grouparraymovingsum.md          |   76 +
 .../reference/grouparraysample.md             |   81 +
 .../reference/grouparraysorted.md             |   48 +
 .../reference/groupbitand.md                  |   46 +
 .../reference/groupbitmap.md                  |   44 +
 .../reference/groupbitmapand.md               |   46 +
 .../reference/groupbitmapor.md                |   46 +
 .../reference/groupbitmapxor.md               |   46 +
 .../reference/groupbitor.md                   |   46 +
 .../reference/groupbitxor.md                  |   46 +
 .../reference/groupuniqarray.md               |   12 +
 .../aggregate-functions/reference/index.md    |   76 +
 .../reference/intervalLengthSum.md            |  108 +
 .../aggregate-functions/reference/kurtpop.md  |   25 +
 .../aggregate-functions/reference/kurtsamp.md |   27 +
 .../reference/mannwhitneyutest.md             |   74 +
 .../aggregate-functions/reference/max.md      |   24 +
 .../aggregate-functions/reference/maxmap.md   |   28 +
 .../reference/meanztest.md                    |   70 +
 .../aggregate-functions/reference/median.md   |   46 +
 .../aggregate-functions/reference/min.md      |   23 +
 .../aggregate-functions/reference/minmap.md   |   28 +
 .../aggregate-functions/reference/quantile.md |   68 +
 .../reference/quantilebfloat16.md             |   68 +
 .../reference/quantiledeterministic.md        |   67 +
 .../reference/quantileexact.md                |  270 ++
 .../reference/quantileexactweighted.md        |   67 +
 .../reference/quantiles.md                    |  115 +
 .../reference/quantiletdigest.md              |   57 +
 .../reference/quantiletdigestweighted.md      |   62 +
 .../reference/quantiletiming.md               |   88 +
 .../reference/quantiletimingweighted.md       |  121 +
 .../aggregate-functions/reference/rankCorr.md |   57 +
 .../reference/simplelinearregression.md       |   42 +
 .../aggregate-functions/reference/skewpop.md  |   25 +
 .../aggregate-functions/reference/skewsamp.md |   27 +
 .../aggregate-functions/reference/sparkbar.md |   64 +
 .../reference/stddevpop.md                    |   11 +
 .../reference/stddevsamp.md                   |   11 +
 .../reference/stochasticlinearregression.md   |   75 +
 .../reference/stochasticlogisticregression.md |   55 +
 .../reference/studentttest.md                 |   73 +
 .../aggregate-functions/reference/sum.md      |    7 +
 .../aggregate-functions/reference/sumcount.md |   46 +
 .../aggregate-functions/reference/sumkahan.md |   40 +
 .../aggregate-functions/reference/summap.md   |   48 +
 .../reference/sumwithoverflow.md              |    9 +
 .../aggregate-functions/reference/topk.md     |   42 +
 .../reference/topkweighted.md                 |   43 +
 .../aggregate-functions/reference/uniq.md     |   39 +
 .../reference/uniqcombined.md                 |   53 +
 .../reference/uniqcombined64.md               |    7 +
 .../reference/uniqexact.md                    |   26 +
 .../reference/uniqhll12.md                    |   40 +
 .../reference/uniqthetasketch.md              |   39 +
 .../aggregate-functions/reference/varpop.md   |   13 +
 .../aggregate-functions/reference/varsamp.md  |   15 +
 .../reference/welchttest.md                   |   72 +
 docs/en/reference/sql-reference/ansi.md       |  190 +
 .../data-types/aggregatefunction.md           |   66 +
 .../sql-reference/data-types/array.md         |   99 +
 .../sql-reference/data-types/boolean.md       |   10 +
 .../sql-reference/data-types/date.md          |   43 +
 .../sql-reference/data-types/date32.md        |   40 +
 .../sql-reference/data-types/datetime.md      |  148 +
 .../sql-reference/data-types/datetime64.md    |  106 +
 .../sql-reference/data-types/decimal.md       |  114 +
 .../sql-reference/data-types/domains/index.md |   30 +
 .../sql-reference/data-types/domains/ipv4.md  |   82 +
 .../sql-reference/data-types/domains/ipv6.md  |   84 +
 .../sql-reference/data-types/enum.md          |  130 +
 .../sql-reference/data-types/fixedstring.md   |   61 +
 .../sql-reference/data-types/float.md         |   92 +
 .../reference/sql-reference/data-types/geo.md |  107 +
 .../sql-reference/data-types/index.md         |   14 +
 .../sql-reference/data-types/int-uint.md      |   37 +
 .../data-types/lowcardinality.md              |   59 +
 .../reference/sql-reference/data-types/map.md |  111 +
 .../data-types/multiword-types.md             |   29 +
 .../nested-data-structures/index.md           |    8 +
 .../nested-data-structures/nested.md          |  106 +
 .../sql-reference/data-types/nullable.md      |   72 +
 .../data-types/simpleaggregatefunction.md     |   42 +
 .../special-data-types/expression.md          |   10 +
 .../data-types/special-data-types/index.md    |   10 +
 .../data-types/special-data-types/interval.md |   84 +
 .../data-types/special-data-types/nothing.md  |   24 +
 .../data-types/special-data-types/set.md      |   10 +
 .../sql-reference/data-types/string.md        |   24 +
 .../sql-reference/data-types/tuple.md         |   78 +
 .../sql-reference/data-types/uuid.md          |   75 +
 .../external-dictionaries/_category_.yml      |    8 +
 .../external-dicts-dict-hierarchical.md       |   67 +
 .../external-dicts-dict-layout.md             |  557 +++
 .../external-dicts-dict-lifetime.md           |  119 +
 .../external-dicts-dict-polygon.md            |  131 +
 .../external-dicts-dict-sources.md            |  818 ++++
 .../external-dicts-dict-structure.md          |  174 +
 .../external-dicts-dict.md                    |   50 +
 .../external-dictionaries/external-dicts.md   |   60 +
 .../sql-reference/dictionaries/index.md       |   16 +
 .../dictionaries/internal-dicts.md            |   52 +
 .../sql-reference/distributed-ddl.md          |   22 +
 .../functions/arithmetic-functions.md         |  157 +
 .../functions/array-functions.md              | 1717 +++++++
 .../sql-reference/functions/array-join.md     |   34 +
 .../sql-reference/functions/bit-functions.md  |  447 ++
 .../functions/bitmap-functions.md             |  537 +++
 .../functions/comparison-functions.md         |   34 +
 .../functions/conditional-functions.md        |  211 +
 .../functions/date-time-functions.md          | 1233 +++++
 .../functions/encoding-functions.md           |  442 ++
 .../functions/encryption-functions.md         |  361 ++
 .../functions/ext-dict-functions.md           |  444 ++
 .../sql-reference/functions/files.md          |   35 +
 .../functions/functions-for-nulls.md          |  311 ++
 .../functions/geo/coordinates.md              |  147 +
 .../sql-reference/functions/geo/geohash.md    |  114 +
 .../sql-reference/functions/geo/h3.md         | 1029 ++++
 .../sql-reference/functions/geo/index.md      |    8 +
 .../sql-reference/functions/geo/s2.md         |  376 ++
 .../sql-reference/functions/hash-functions.md | 1496 ++++++
 .../sql-reference/functions/in-functions.md   |   11 +
 .../sql-reference/functions/index.md          |  252 +
 .../sql-reference/functions/introspection.md  |  478 ++
 .../functions/ip-address-functions.md         |  448 ++
 .../sql-reference/functions/json-functions.md |  466 ++
 .../functions/logical-functions.md            |  194 +
 .../functions/machine-learning-functions.md   |   18 +
 .../sql-reference/functions/math-functions.md |  550 +++
 .../sql-reference/functions/nlp-functions.md  |  133 +
 .../functions/other-functions.md              | 2505 ++++++++++
 .../functions/random-functions.md             |  105 +
 .../functions/rounding-functions.md           |  201 +
 .../functions/splitting-merging-functions.md  |  339 ++
 .../functions/string-functions.md             | 1077 +++++
 .../functions/string-replace-functions.md     |   95 +
 .../functions/string-search-functions.md      |  819 ++++
 .../functions/time-window-functions.md        |  112 +
 .../functions/tuple-functions.md              | 1060 +++++
 .../functions/tuple-map-functions.md          |  434 ++
 .../functions/type-conversion-functions.md    | 1743 +++++++
 .../sql-reference/functions/url-functions.md  |  467 ++
 .../sql-reference/functions/uuid-functions.md |  266 ++
 .../functions/ym-dict-functions.md            |  152 +
 docs/en/reference/sql-reference/index.md      |   16 +
 .../sql-reference/operators/exists.md         |   45 +
 .../reference/sql-reference/operators/in.md   |  251 +
 .../sql-reference/operators/index.md          |  377 ++
 .../sql-reference/statements/alter/column.md  |  260 +
 .../sql-reference/statements/alter/comment.md |   58 +
 .../statements/alter/constraint.md            |   23 +
 .../sql-reference/statements/alter/delete.md  |   28 +
 .../sql-reference/statements/alter/index.md   |   62 +
 .../statements/alter/index/index.md           |   23 +
 .../statements/alter/order-by.md              |   18 +
 .../statements/alter/partition.md             |  328 ++
 .../statements/alter/projection.md            |   25 +
 .../sql-reference/statements/alter/quota.md   |   39 +
 .../sql-reference/statements/alter/role.md    |   16 +
 .../statements/alter/row-policy.md            |   19 +
 .../statements/alter/sample-by.md             |   20 +
 .../sql-reference/statements/alter/setting.md |   60 +
 .../statements/alter/settings-profile.md      |   16 +
 .../sql-reference/statements/alter/ttl.md     |   85 +
 .../sql-reference/statements/alter/update.md  |   29 +
 .../sql-reference/statements/alter/user.md    |   63 +
 .../sql-reference/statements/alter/view.md    |   44 +
 .../sql-reference/statements/attach.md        |   81 +
 .../sql-reference/statements/check-table.md   |   69 +
 .../statements/create/database.md             |   58 +
 .../statements/create/dictionary.md           |   99 +
 .../statements/create/function.md             |   59 +
 .../sql-reference/statements/create/index.md  |   21 +
 .../sql-reference/statements/create/quota.md  |   39 +
 .../sql-reference/statements/create/role.md   |   47 +
 .../statements/create/row-policy.md           |   90 +
 .../statements/create/settings-profile.md     |   26 +
 .../sql-reference/statements/create/table.md  |  445 ++
 .../sql-reference/statements/create/user.md   |  104 +
 .../sql-reference/statements/create/view.md   |  365 ++
 .../statements/describe-table.md              |   69 +
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diff --git a/.github/workflows/deploy-github.yml b/.github/workflows/deploy-github.yml
index 7d72ad9b99a..c135dc420f3 100644
--- a/.github/workflows/deploy-github.yml
+++ b/.github/workflows/deploy-github.yml
@@ -39,6 +39,7 @@ jobs:
         uses: JamesIves/github-pages-deploy-action@v4.3.0
         with:
           repository-name: ClickHouse/clickhouse-docs-content
+          token: ${{ secrets.GITHUB_TOKEN }}
           branch: gh-pages
           folder: .
         env:
diff --git a/.gitignore b/.gitignore
index fb9a46a1b5a..c11afe4cd36 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,5 @@
 node_modules
 .docusaurus
 build
-docs/en/reference
 
 **/.DS_Store
diff --git a/docs/en/reference/development/_category_.yml b/docs/en/reference/development/_category_.yml
new file mode 100644
index 00000000000..9e622150f74
--- /dev/null
+++ b/docs/en/reference/development/_category_.yml
@@ -0,0 +1,8 @@
+position: 100
+label: 'Building ClickHouse'
+collapsible: true
+collapsed: true
+link:
+  type: generated-index
+  title: Building ClickHouse
+  slug: /en/development
\ No newline at end of file
diff --git a/docs/en/reference/development/adding_test_queries.md b/docs/en/reference/development/adding_test_queries.md
new file mode 100644
index 00000000000..9b993a96ed5
--- /dev/null
+++ b/docs/en/reference/development/adding_test_queries.md
@@ -0,0 +1,157 @@
+---
+sidebar_label: Adding Test Queries
+sidebar_position: 63
+description: Instructions on how to add a test case to ClickHouse continuous integration
+---
+
+# How to add test queries to ClickHouse CI
+
+ClickHouse has hundreds (or even thousands) of features. Every commit gets checked by a complex set of tests containing many thousands of test cases.
+
+The core functionality is very well tested, but some corner-cases and different combinations of features can be uncovered with ClickHouse CI.
+
+Most of the bugs/regressions we see happen in that 'grey area' where test coverage is poor.
+
+And we are very interested in covering most of the possible scenarios and feature combinations used in real life by tests.
+
+## Why adding tests
+
+Why/when you should add a test case into ClickHouse code:
+1) you use some complicated scenarios / feature combinations / you have some corner case which is probably not widely used
+2) you see that certain behavior gets changed between version w/o notifications in the changelog
+3) you just want to help to improve ClickHouse quality and ensure the features you use will not be broken in the future releases
+4) once the test is added/accepted, you can be sure the corner case you check will never be accidentally broken.
+5) you will be a part of great open-source community
+6) your name will be visible in the `system.contributors` table!
+7) you will make a world bit better :)
+
+### Steps to do
+
+#### Prerequisite
+
+I assume you run some Linux machine (you can use docker / virtual machines on other OS) and any modern browser / internet connection, and you have some basic Linux & SQL skills.
+
+Any highly specialized knowledge is not needed (so you don't need to know C++ or know something about how ClickHouse CI works).
+
+
+#### Preparation
+
+1) [create GitHub account](https://github.com/join) (if you haven't one yet)
+2) [setup git](https://docs.github.com/en/free-pro-team@latest/github/getting-started-with-github/set-up-git)
+```bash
+# for Ubuntu
+sudo apt-get update
+sudo apt-get install git
+
+git config --global user.name "John Doe" # fill with your name
+git config --global user.email "email@example.com" # fill with your email
+
+```
+3) [fork ClickHouse project](https://docs.github.com/en/free-pro-team@latest/github/getting-started-with-github/fork-a-repo) - just open [https://github.com/ClickHouse/ClickHouse](https://github.com/ClickHouse/ClickHouse) and press fork button in the top right corner:
+![fork repo](https://github-images.s3.amazonaws.com/help/bootcamp/Bootcamp-Fork.png)
+
+4) clone your fork to some folder on your PC, for example, `~/workspace/ClickHouse`
+```
+mkdir ~/workspace && cd ~/workspace
+git clone https://github.com/< your GitHub username>/ClickHouse
+cd ClickHouse
+git remote add upstream https://github.com/ClickHouse/ClickHouse
+```
+
+#### New branch for the test
+
+1) create a new branch from the latest clickhouse master
+```
+cd ~/workspace/ClickHouse
+git fetch upstream
+git checkout -b name_for_a_branch_with_my_test upstream/master
+```
+
+#### Install & run clickhouse
+
+1) install `clickhouse-server` (follow [official docs](https://clickhouse.com/docs/en/getting-started/install/))
+2) install test configurations (it will use Zookeeper mock implementation and adjust some settings)
+```
+cd ~/workspace/ClickHouse/tests/config
+sudo ./install.sh
+```
+3) run clickhouse-server
+```
+sudo systemctl restart clickhouse-server
+```
+
+#### Creating the test file
+
+
+1) find the number for your test - find the file with the biggest number in `tests/queries/0_stateless/`
+
+```sh
+$ cd ~/workspace/ClickHouse
+$ ls tests/queries/0_stateless/[0-9]*.reference | tail -n 1
+tests/queries/0_stateless/01520_client_print_query_id.reference
+```
+Currently, the last number for the test is `01520`, so my test will have the number `01521`
+
+2) create an SQL file with the next number and name of the feature you test
+
+```sh
+touch tests/queries/0_stateless/01521_dummy_test.sql
+```
+
+3) edit SQL file with your favorite editor (see hint of creating tests below)
+```sh
+vim tests/queries/0_stateless/01521_dummy_test.sql
+```
+
+
+4) run the test, and put the result of that into the reference file:
+```
+clickhouse-client -nmT < tests/queries/0_stateless/01521_dummy_test.sql | tee tests/queries/0_stateless/01521_dummy_test.reference
+```
+
+5) ensure everything is correct, if the test output is incorrect (due to some bug for example), adjust the reference file using text editor.
+
+#### How to create a good test
+
+- A test should be
+	- minimal - create only tables related to tested functionality, remove unrelated columns and parts of query
+	- fast - should not take longer than a few seconds (better subseconds)
+	- correct - fails then feature is not working
+        - deterministic
+	- isolated / stateless
+		- don't rely on some environment things
+		- don't rely on timing when possible
+- try to cover corner cases (zeros / Nulls / empty sets / throwing exceptions)
+- to test that query return errors, you can put special comment after the query: `-- { serverError 60 }` or `-- { clientError 20 }`
+- don't switch databases (unless necessary)
+- you can create several table replicas on the same node if needed
+- you can use one of the test cluster definitions when needed (see system.clusters)
+- use `number` / `numbers_mt` / `zeros` / `zeros_mt` and similar for queries / to initialize data when applicable
+- clean up the created objects after test and before the test (DROP IF EXISTS) - in case of some dirty state
+- prefer sync mode of operations (mutations, merges, etc.)
+- use other SQL files in the `0_stateless` folder as an example
+- ensure the feature / feature combination you want to test is not yet covered with existing tests
+
+#### Test naming rules
+
+It's important to name tests correctly, so one could turn some tests subset off in clickhouse-test invocation.
+
+| Tester flag| What should be in test name | When flag should be added |
+|---|---|---|---|
+| `--[no-]zookeeper`| "zookeeper" or "replica" | Test uses tables from ReplicatedMergeTree family |
+| `--[no-]shard` | "shard" or "distributed" or "global"| Test using connections to 127.0.0.2 or similar |
+| `--[no-]long` | "long" or "deadlock" or "race" | Test runs longer than 60 seconds |
+
+#### Commit / push / create PR.
+
+1) commit & push your changes
+```sh
+cd ~/workspace/ClickHouse
+git add tests/queries/0_stateless/01521_dummy_test.sql
+git add tests/queries/0_stateless/01521_dummy_test.reference
+git commit # use some nice commit message when possible
+git push origin HEAD
+```
+2) use a link which was shown during the push, to create a PR into the main repo
+3) adjust the PR title and contents, in `Changelog category (leave one)` keep
+`Build/Testing/Packaging Improvement`, fill the rest of the fields if you want.
diff --git a/docs/en/reference/development/architecture.md b/docs/en/reference/development/architecture.md
new file mode 100644
index 00000000000..b5cb6c321ac
--- /dev/null
+++ b/docs/en/reference/development/architecture.md
@@ -0,0 +1,202 @@
+---
+sidebar_label: Architecture Overview
+sidebar_position: 62
+---
+
+# Overview of ClickHouse Architecture
+
+ClickHouse is a true column-oriented DBMS. Data is stored by columns, and during the execution of arrays (vectors or chunks of columns). 
+Whenever possible, operations are dispatched on arrays, rather than on individual values. It is called “vectorized query execution” and it helps lower the cost of actual data processing.
+
+> This idea is nothing new. It dates back to the `APL` (A programming language, 1957) and its descendants: `A +` (APL dialect), `J` (1990), `K` (1993), and `Q` (programming language from Kx Systems, 2003). Array programming is used in scientific data processing. Neither is this idea something new in relational databases: for example, it is used in the `VectorWise` system (also known as Actian Vector Analytic Database by Actian Corporation).
+
+There are two different approaches for speeding up query processing: vectorized query execution and runtime code generation. The latter removes all indirection and dynamic dispatch. Neither of these approaches is strictly better than the other. Runtime code generation can be better when it fuses many operations, thus fully utilizing CPU execution units and the pipeline. Vectorized query execution can be less practical because it involves temporary vectors that must be written to the cache and read back. If the temporary data does not fit in the L2 cache, this becomes an issue. But vectorized query execution more easily utilizes the SIMD capabilities of the CPU. A [research paper](http://15721.courses.cs.cmu.edu/spring2016/papers/p5-sompolski.pdf) written by our friends shows that it is better to combine both approaches. ClickHouse uses vectorized query execution and has limited initial support for runtime code generation.
+
+## Columns {#columns}
+
+`IColumn` interface is used to represent columns in memory (actually, chunks of columns). This interface provides helper methods for the implementation of various relational operators. Almost all operations are immutable: they do not modify the original column, but create a new modified one. For example, the `IColumn :: filter` method accepts a filter byte mask. It is used for the `WHERE` and `HAVING` relational operators. Additional examples: the `IColumn :: permute` method to support `ORDER BY`, the `IColumn :: cut` method to support `LIMIT`.
+
+Various `IColumn` implementations (`ColumnUInt8`, `ColumnString`, and so on) are responsible for the memory layout of columns. The memory layout is usually a contiguous array. For the integer type of columns, it is just one contiguous array, like `std :: vector`. For `String` and `Array` columns, it is two vectors: one for all array elements, placed contiguously, and a second one for offsets to the beginning of each array. There is also `ColumnConst` that stores just one value in memory, but looks like a column.
+
+## Field {#field}
+
+Nevertheless, it is possible to work with individual values as well. To represent an individual value, the `Field` is used. `Field` is just a discriminated union of `UInt64`, `Int64`, `Float64`, `String` and `Array`. `IColumn` has the `operator []` method to get the n-th value as a `Field`, and the `insert` method to append a `Field` to the end of a column. These methods are not very efficient, because they require dealing with temporary `Field` objects representing an individual value. There are more efficient methods, such as `insertFrom`, `insertRangeFrom`, and so on.
+
+`Field` does not have enough information about a specific data type for a table. For example, `UInt8`, `UInt16`, `UInt32`, and `UInt64` are all represented as `UInt64` in a `Field`.
+
+## Leaky Abstractions {#leaky-abstractions}
+
+`IColumn` has methods for common relational transformations of data, but they do not meet all needs. For example, `ColumnUInt64` does not have a method to calculate the sum of two columns, and `ColumnString` does not have a method to run a substring search. These countless routines are implemented outside of `IColumn`.
+
+Various functions on columns can be implemented in a generic, non-efficient way using `IColumn` methods to extract `Field` values, or in a specialized way using knowledge of inner memory layout of data in a specific `IColumn` implementation. It is implemented by casting functions to a specific `IColumn` type and deal with internal representation directly. For example, `ColumnUInt64` has the `getData` method that returns a reference to an internal array, then a separate routine reads or fills that array directly. We have “leaky abstractions” to allow efficient specializations of various routines.
+
+## Data Types {#data_types}
+
+`IDataType` is responsible for serialization and deserialization: for reading and writing chunks of columns or individual values in binary or text form. `IDataType` directly corresponds to data types in tables. For example, there are `DataTypeUInt32`, `DataTypeDateTime`, `DataTypeString` and so on.
+
+`IDataType` and `IColumn` are only loosely related to each other. Different data types can be represented in memory by the same `IColumn` implementations. For example, `DataTypeUInt32` and `DataTypeDateTime` are both represented by `ColumnUInt32` or `ColumnConstUInt32`. In addition, the same data type can be represented by different `IColumn` implementations. For example, `DataTypeUInt8` can be represented by `ColumnUInt8` or `ColumnConstUInt8`.
+
+`IDataType` only stores metadata. For instance, `DataTypeUInt8` does not store anything at all (except virtual pointer `vptr`) and `DataTypeFixedString` stores just `N` (the size of fixed-size strings).
+
+`IDataType` has helper methods for various data formats. Examples are methods to serialize a value with possible quoting, to serialize a value for JSON, and to serialize a value as part of the XML format. There is no direct correspondence to data formats. For example, the different data formats `Pretty` and `TabSeparated` can use the same `serializeTextEscaped` helper method from the `IDataType` interface.
+
+## Block {#block}
+
+A `Block` is a container that represents a subset (chunk) of a table in memory. It is just a set of triples: `(IColumn, IDataType, column name)`. During query execution, data is processed by `Block`s. If we have a `Block`, we have data (in the `IColumn` object), we have information about its type (in `IDataType`) that tells us how to deal with that column, and we have the column name. It could be either the original column name from the table or some artificial name assigned for getting temporary results of calculations.
+
+When we calculate some function over columns in a block, we add another column with its result to the block, and we do not touch columns for arguments of the function because operations are immutable. Later, unneeded columns can be removed from the block, but not modified. It is convenient for the elimination of common subexpressions.
+
+Blocks are created for every processed chunk of data. Note that for the same type of calculation, the column names and types remain the same for different blocks, and only column data changes. It is better to split block data from the block header because small block sizes have a high overhead of temporary strings for copying shared_ptrs and column names.
+
+## Block Streams {#block-streams}
+
+Block streams are for processing data. We use streams of blocks to read data from somewhere, perform data transformations, or write data to somewhere. `IBlockInputStream` has the `read` method to fetch the next block while available. `IBlockOutputStream` has the `write` method to push the block somewhere.
+
+Streams are responsible for:
+
+1.  Reading or writing to a table. The table just returns a stream for reading or writing blocks.
+2.  Implementing data formats. For example, if you want to output data to a terminal in `Pretty` format, you create a block output stream where you push blocks, and it formats them.
+3.  Performing data transformations. Let’s say you have `IBlockInputStream` and want to create a filtered stream. You create `FilterBlockInputStream` and initialize it with your stream. Then when you pull a block from `FilterBlockInputStream`, it pulls a block from your stream, filters it, and returns the filtered block to you. Query execution pipelines are represented this way.
+
+There are more sophisticated transformations. For example, when you pull from `AggregatingBlockInputStream`, it reads all data from its source, aggregates it, and then returns a stream of aggregated data for you. Another example: `UnionBlockInputStream` accepts many input sources in the constructor and also a number of threads. It launches multiple threads and reads from multiple sources in parallel.
+
+> Block streams use the “pull” approach to control flow: when you pull a block from the first stream, it consequently pulls the required blocks from nested streams, and the entire execution pipeline will work. Neither “pull” nor “push” is the best solution, because control flow is implicit, and that limits the implementation of various features like simultaneous execution of multiple queries (merging many pipelines together). This limitation could be overcome with coroutines or just running extra threads that wait for each other. We may have more possibilities if we make control flow explicit: if we locate the logic for passing data from one calculation unit to another outside of those calculation units. Read this [article](http://journal.stuffwithstuff.com/2013/01/13/iteration-inside-and-out/) for more thoughts.
+
+We should note that the query execution pipeline creates temporary data at each step. We try to keep block size small enough so that temporary data fits in the CPU cache. With that assumption, writing and reading temporary data is almost free in comparison with other calculations. We could consider an alternative, which is to fuse many operations in the pipeline together. It could make the pipeline as short as possible and remove much of the temporary data, which could be an advantage, but it also has drawbacks. For example, a split pipeline makes it easy to implement caching intermediate data, stealing intermediate data from similar queries running at the same time, and merging pipelines for similar queries.
+
+## Formats {#formats}
+
+Data formats are implemented with block streams. There are “presentational” formats only suitable for the output of data to the client, such as `Pretty` format, which provides only `IBlockOutputStream`. And there are input/output formats, such as `TabSeparated` or `JSONEachRow`.
+
+There are also row streams: `IRowInputStream` and `IRowOutputStream`. They allow you to pull/push data by individual rows, not by blocks. And they are only needed to simplify the implementation of row-oriented formats. The wrappers `BlockInputStreamFromRowInputStream` and `BlockOutputStreamFromRowOutputStream` allow you to convert row-oriented streams to regular block-oriented streams.
+
+## I/O {#io}
+
+For byte-oriented input/output, there are `ReadBuffer` and `WriteBuffer` abstract classes. They are used instead of C++ `iostream`s. Don’t worry: every mature C++ project is using something other than `iostream`s for good reasons.
+
+`ReadBuffer` and `WriteBuffer` are just a contiguous buffer and a cursor pointing to the position in that buffer. Implementations may own or not own the memory for the buffer. There is a virtual method to fill the buffer with the following data (for `ReadBuffer`) or to flush the buffer somewhere (for `WriteBuffer`). The virtual methods are rarely called.
+
+Implementations of `ReadBuffer`/`WriteBuffer` are used for working with files and file descriptors and network sockets, for implementing compression (`CompressedWriteBuffer` is initialized with another WriteBuffer and performs compression before writing data to it), and for other purposes – the names `ConcatReadBuffer`, `LimitReadBuffer`, and `HashingWriteBuffer` speak for themselves.
+
+Read/WriteBuffers only deal with bytes. There are functions from `ReadHelpers` and `WriteHelpers` header files to help with formatting input/output. For example, there are helpers to write a number in decimal format.
+
+Let’s look at what happens when you want to write a result set in `JSON` format to stdout. You have a result set ready to be fetched from `IBlockInputStream`. You create `WriteBufferFromFileDescriptor(STDOUT_FILENO)` to write bytes to stdout. You create `JSONRowOutputStream`, initialized with that `WriteBuffer`, to write rows in `JSON` to stdout. You create `BlockOutputStreamFromRowOutputStream` on top of it, to represent it as `IBlockOutputStream`. Then you call `copyData` to transfer data from `IBlockInputStream` to `IBlockOutputStream`, and everything works. Internally, `JSONRowOutputStream` will write various JSON delimiters and call the `IDataType::serializeTextJSON` method with a reference to `IColumn` and the row number as arguments. Consequently, `IDataType::serializeTextJSON` will call a method from `WriteHelpers.h`: for example, `writeText` for numeric types and `writeJSONString` for `DataTypeString`.
+
+## Tables {#tables}
+
+The `IStorage` interface represents tables. Different implementations of that interface are different table engines. Examples are `StorageMergeTree`, `StorageMemory`, and so on. Instances of these classes are just tables.
+
+The key `IStorage` methods are `read` and `write`. There are also `alter`, `rename`, `drop`, and so on. The `read` method accepts the following arguments: the set of columns to read from a table, the `AST` query to consider, and the desired number of streams to return. It returns one or multiple `IBlockInputStream` objects and information about the stage of data processing that was completed inside a table engine during query execution.
+
+In most cases, the read method is only responsible for reading the specified columns from a table, not for any further data processing. All further data processing is done by the query interpreter and is outside the responsibility of `IStorage`.
+
+But there are notable exceptions:
+
+-   The AST query is passed to the `read` method, and the table engine can use it to derive index usage and to read fewer data from a table.
+-   Sometimes the table engine can process data itself to a specific stage. For example, `StorageDistributed` can send a query to remote servers, ask them to process data to a stage where data from different remote servers can be merged, and return that preprocessed data. The query interpreter then finishes processing the data.
+
+The table’s `read` method can return multiple `IBlockInputStream` objects to allow parallel data processing. These multiple block input streams can read from a table in parallel. Then you can wrap these streams with various transformations (such as expression evaluation or filtering) that can be calculated independently and create a `UnionBlockInputStream` on top of them, to read from multiple streams in parallel.
+
+There are also `TableFunction`s. These are functions that return a temporary `IStorage` object to use in the `FROM` clause of a query.
+
+To get a quick idea of how to implement your table engine, look at something simple, like `StorageMemory` or `StorageTinyLog`.
+
+> As the result of the `read` method, `IStorage` returns `QueryProcessingStage` – information about what parts of the query were already calculated inside storage.
+
+## Parsers {#parsers}
+
+A hand-written recursive descent parser parses a query. For example, `ParserSelectQuery` just recursively calls the underlying parsers for various parts of the query. Parsers create an `AST`. The `AST` is represented by nodes, which are instances of `IAST`.
+
+> Parser generators are not used for historical reasons.
+
+## Interpreters {#interpreters}
+
+Interpreters are responsible for creating the query execution pipeline from an `AST`. There are simple interpreters, such as `InterpreterExistsQuery` and `InterpreterDropQuery`, or the more sophisticated `InterpreterSelectQuery`. The query execution pipeline is a combination of block input or output streams. For example, the result of interpreting the `SELECT` query is the `IBlockInputStream` to read the result set from; the result of the INSERT query is the `IBlockOutputStream` to write data for insertion to, and the result of interpreting the `INSERT SELECT` query is the `IBlockInputStream` that returns an empty result set on the first read, but that copies data from `SELECT` to `INSERT` at the same time.
+
+`InterpreterSelectQuery` uses `ExpressionAnalyzer` and `ExpressionActions` machinery for query analysis and transformations. This is where most rule-based query optimizations are done. `ExpressionAnalyzer` is quite messy and should be rewritten: various query transformations and optimizations should be extracted to separate classes to allow modular transformations of query.
+
+## Functions {#functions}
+
+There are ordinary functions and aggregate functions. For aggregate functions, see the next section.
+
+Ordinary functions do not change the number of rows – they work as if they are processing each row independently. In fact, functions are not called for individual rows, but for `Block`’s of data to implement vectorized query execution.
+
+There are some miscellaneous functions, like [blockSize](../sql-reference/functions/other-functions.md#function-blocksize), [rowNumberInBlock](../sql-reference/functions/other-functions.md#function-rownumberinblock), and [runningAccumulate](../sql-reference/functions/other-functions.md#runningaccumulate), that exploit block processing and violate the independence of rows.
+
+ClickHouse has strong typing, so there’s no implicit type conversion. If a function does not support a specific combination of types, it throws an exception. But functions can work (be overloaded) for many different combinations of types. For example, the `plus` function (to implement the `+` operator) works for any combination of numeric types: `UInt8` + `Float32`, `UInt16` + `Int8`, and so on. Also, some variadic functions can accept any number of arguments, such as the `concat` function.
+
+Implementing a function may be slightly inconvenient because a function explicitly dispatches supported data types and supported `IColumns`. For example, the `plus` function has code generated by instantiation of a C++ template for each combination of numeric types, and constant or non-constant left and right arguments.
+
+It is an excellent place to implement runtime code generation to avoid template code bloat. Also, it makes it possible to add fused functions like fused multiply-add or to make multiple comparisons in one loop iteration.
+
+Due to vectorized query execution, functions are not short-circuited. For example, if you write `WHERE f(x) AND g(y)`, both sides are calculated, even for rows, when `f(x)` is zero (except when `f(x)` is a zero constant expression). But if the selectivity of the `f(x)` condition is high, and calculation of `f(x)` is much cheaper than `g(y)`, it’s better to implement multi-pass calculation. It would first calculate `f(x)`, then filter columns by the result, and then calculate `g(y)` only for smaller, filtered chunks of data.
+
+## Aggregate Functions {#aggregate-functions}
+
+Aggregate functions are stateful functions. They accumulate passed values into some state and allow you to get results from that state. They are managed with the `IAggregateFunction` interface. States can be rather simple (the state for `AggregateFunctionCount` is just a single `UInt64` value) or quite complex (the state of `AggregateFunctionUniqCombined` is a combination of a linear array, a hash table, and a `HyperLogLog` probabilistic data structure).
+
+States are allocated in `Arena` (a memory pool) to deal with multiple states while executing a high-cardinality `GROUP BY` query. States can have a non-trivial constructor and destructor: for example, complicated aggregation states can allocate additional memory themselves. It requires some attention to creating and destroying states and properly passing their ownership and destruction order.
+
+Aggregation states can be serialized and deserialized to pass over the network during distributed query execution or to write them on the disk where there is not enough RAM. They can even be stored in a table with the `DataTypeAggregateFunction` to allow incremental aggregation of data.
+
+> The serialized data format for aggregate function states is not versioned right now. It is ok if aggregate states are only stored temporarily. But we have the `AggregatingMergeTree` table engine for incremental aggregation, and people are already using it in production. It is the reason why backward compatibility is required when changing the serialized format for any aggregate function in the future.
+
+## Server {#server}
+
+The server implements several different interfaces:
+
+-   An HTTP interface for any foreign clients.
+-   A TCP interface for the native ClickHouse client and for cross-server communication during distributed query execution.
+-   An interface for transferring data for replication.
+
+Internally, it is just a primitive multithreaded server without coroutines or fibers. Since the server is not designed to process a high rate of simple queries but to process a relatively low rate of complex queries, each of them can process a vast amount of data for analytics.
+
+The server initializes the `Context` class with the necessary environment for query execution: the list of available databases, users and access rights, settings, clusters, the process list, the query log, and so on. Interpreters use this environment.
+
+We maintain full backward and forward compatibility for the server TCP protocol: old clients can talk to new servers, and new clients can talk to old servers. But we do not want to maintain it eternally, and we are removing support for old versions after about one year.
+
+:::note    
+For most external applications, we recommend using the HTTP interface because it is simple and easy to use. The TCP protocol is more tightly linked to internal data structures: it uses an internal format for passing blocks of data, and it uses custom framing for compressed data. We haven’t released a C library for that protocol because it requires linking most of the ClickHouse codebase, which is not practical.
+:::
+
+## Distributed Query Execution {#distributed-query-execution}
+
+Servers in a cluster setup are mostly independent. You can create a `Distributed` table on one or all servers in a cluster. The `Distributed` table does not store data itself – it only provides a “view” to all local tables on multiple nodes of a cluster. When you SELECT from a `Distributed` table, it rewrites that query, chooses remote nodes according to load balancing settings, and sends the query to them. The `Distributed` table requests remote servers to process a query just up to a stage where intermediate results from different servers can be merged. Then it receives the intermediate results and merges them. The distributed table tries to distribute as much work as possible to remote servers and does not send much intermediate data over the network.
+
+Things become more complicated when you have subqueries in IN or JOIN clauses, and each of them uses a `Distributed` table. We have different strategies for the execution of these queries.
+
+There is no global query plan for distributed query execution. Each node has its local query plan for its part of the job. We only have simple one-pass distributed query execution: we send queries for remote nodes and then merge the results. But this is not feasible for complicated queries with high cardinality GROUP BYs or with a large amount of temporary data for JOIN. In such cases, we need to “reshuffle” data between servers, which requires additional coordination. ClickHouse does not support that kind of query execution, and we need to work on it.
+
+## Merge Tree {#merge-tree}
+
+`MergeTree` is a family of storage engines that supports indexing by primary key. The primary key can be an arbitrary tuple of columns or expressions. Data in a `MergeTree` table is stored in “parts”. Each part stores data in the primary key order, so data is ordered lexicographically by the primary key tuple. All the table columns are stored in separate `column.bin` files in these parts. The files consist of compressed blocks. Each block is usually from 64 KB to 1 MB of uncompressed data, depending on the average value size. The blocks consist of column values placed contiguously one after the other. Column values are in the same order for each column (the primary key defines the order), so when you iterate by many columns, you get values for the corresponding rows.
+
+The primary key itself is “sparse”. It does not address every single row, but only some ranges of data. A separate `primary.idx` file has the value of the primary key for each N-th row, where N is called `index_granularity` (usually, N = 8192). Also, for each column, we have `column.mrk` files with “marks”, which are offsets to each N-th row in the data file. Each mark is a pair: the offset in the file to the beginning of the compressed block, and the offset in the decompressed block to the beginning of data. Usually, compressed blocks are aligned by marks, and the offset in the decompressed block is zero. Data for `primary.idx` always resides in memory, and data for `column.mrk` files is cached.
+
+When we are going to read something from a part in `MergeTree`, we look at `primary.idx` data and locate ranges that could contain requested data, then look at `column.mrk` data and calculate offsets for where to start reading those ranges. Because of sparseness, excess data may be read. ClickHouse is not suitable for a high load of simple point queries, because the entire range with `index_granularity` rows must be read for each key, and the entire compressed block must be decompressed for each column. We made the index sparse because we must be able to maintain trillions of rows per single server without noticeable memory consumption for the index. Also, because the primary key is sparse, it is not unique: it cannot check the existence of the key in the table at INSERT time. You could have many rows with the same key in a table.
+
+When you `INSERT` a bunch of data into `MergeTree`, that bunch is sorted by primary key order and forms a new part. There are background threads that periodically select some parts and merge them into a single sorted part to keep the number of parts relatively low. That’s why it is called `MergeTree`. Of course, merging leads to “write amplification”. All parts are immutable: they are only created and deleted, but not modified. When SELECT is executed, it holds a snapshot of the table (a set of parts). After merging, we also keep old parts for some time to make a recovery after failure easier, so if we see that some merged part is probably broken, we can replace it with its source parts.
+
+`MergeTree` is not an LSM tree because it does not contain MEMTABLE and LOG: inserted data is written directly to the filesystem. This behavior makes MergeTree much more suitable to insert data in batches. Therefore frequently inserting small amounts of rows is not ideal for MergeTree. For example, a couple of rows per second is OK, but doing it a thousand times a second is not optimal for MergeTree. However, there is an async insert mode for small inserts to overcome this limitation. We did it this way for simplicity’s sake, and because we are already inserting data in batches in our applications
+
+There are MergeTree engines that are doing additional work during background merges. Examples are `CollapsingMergeTree` and `AggregatingMergeTree`. This could be treated as special support for updates. Keep in mind that these are not real updates because users usually have no control over the time when background merges are executed, and data in a `MergeTree` table is almost always stored in more than one part, not in completely merged form.
+
+## Replication {#replication}
+
+Replication in ClickHouse can be configured on a per-table basis. You could have some replicated and some non-replicated tables on the same server. You could also have tables replicated in different ways, such as one table with two-factor replication and another with three-factor.
+
+Replication is implemented in the `ReplicatedMergeTree` storage engine. The path in `ZooKeeper` is specified as a parameter for the storage engine. All tables with the same path in `ZooKeeper` become replicas of each other: they synchronize their data and maintain consistency. Replicas can be added and removed dynamically simply by creating or dropping a table.
+
+Replication uses an asynchronous multi-master scheme. You can insert data into any replica that has a session with `ZooKeeper`, and data is replicated to all other replicas asynchronously. Because ClickHouse does not support UPDATEs, replication is conflict-free. As there is no quorum acknowledgment of inserts, just-inserted data might be lost if one node fails.
+
+Metadata for replication is stored in ZooKeeper. There is a replication log that lists what actions to do. Actions are: get part; merge parts; drop a partition, and so on. Each replica copies the replication log to its queue and then executes the actions from the queue. For example, on insertion, the “get the part” action is created in the log, and every replica downloads that part. Merges are coordinated between replicas to get byte-identical results. All parts are merged in the same way on all replicas. One of the leaders initiates a new merge first and writes “merge parts” actions to the log. Multiple replicas (or all) can be leaders at the same time. A replica can be prevented from becoming a leader using the `merge_tree` setting `replicated_can_become_leader`. The leaders are responsible for scheduling background merges.
+
+Replication is physical: only compressed parts are transferred between nodes, not queries. Merges are processed on each replica independently in most cases to lower the network costs by avoiding network amplification. Large merged parts are sent over the network only in cases of significant replication lag.
+
+Besides, each replica stores its state in ZooKeeper as the set of parts and its checksums. When the state on the local filesystem diverges from the reference state in ZooKeeper, the replica restores its consistency by downloading missing and broken parts from other replicas. When there is some unexpected or broken data in the local filesystem, ClickHouse does not remove it, but moves it to a separate directory and forgets it.
+
+:::note    
+The ClickHouse cluster consists of independent shards, and each shard consists of replicas. The cluster is **not elastic**, so after adding a new shard, data is not rebalanced between shards automatically. Instead, the cluster load is supposed to be adjusted to be uneven. This implementation gives you more control, and it is ok for relatively small clusters, such as tens of nodes. But for clusters with hundreds of nodes that we are using in production, this approach becomes a significant drawback. We should implement a table engine that spans across the cluster with dynamically replicated regions that could be split and balanced between clusters automatically.
+:::
+
+[Original article](https://clickhouse.com/docs/en/development/architecture/)
diff --git a/docs/en/reference/development/browse-code.md b/docs/en/reference/development/browse-code.md
new file mode 100644
index 00000000000..da924c359ff
--- /dev/null
+++ b/docs/en/reference/development/browse-code.md
@@ -0,0 +1,13 @@
+---
+sidebar_label: Source Code Browser
+sidebar_position: 72
+description: Various ways to browse and edit the source code
+---
+
+# Browse ClickHouse Source Code 
+
+You can use the **Woboq** online code browser available [here](https://clickhouse.com/codebrowser/ClickHouse/src/index.html). It provides code navigation and semantic highlighting, search and indexing. The code snapshot is updated daily.
+
+Also, you can browse sources on [GitHub](https://github.com/ClickHouse/ClickHouse) as usual.
+
+If you’re interested what IDE to use, we recommend CLion, QT Creator, VS Code and KDevelop (with caveats). You can use any favorite IDE. Vim and Emacs also count.
diff --git a/docs/en/reference/development/build-cross-arm.md b/docs/en/reference/development/build-cross-arm.md
new file mode 100644
index 00000000000..305c09ae217
--- /dev/null
+++ b/docs/en/reference/development/build-cross-arm.md
@@ -0,0 +1,38 @@
+---
+sidebar_position: 67
+sidebar_label: Build on Linux for AARCH64 (ARM64)
+---
+
+# How to Build ClickHouse on Linux for AARCH64 (ARM64) Architecture 
+
+This is for the case when you have Linux machine and want to use it to build `clickhouse` binary that will run on another Linux machine with AARCH64 CPU architecture. 
+This is intended for continuous integration checks that run on Linux servers.
+
+The cross-build for AARCH64 is based on the [Build instructions](../development/build.md), follow them first.
+
+## Install Clang-13
+
+Follow the instructions from https://apt.llvm.org/ for your Ubuntu or Debian setup or do
+```
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
+```
+
+## Install Cross-Compilation Toolset {#install-cross-compilation-toolset}
+
+``` bash
+cd ClickHouse
+mkdir -p build-aarch64/cmake/toolchain/linux-aarch64
+wget 'https://developer.arm.com/-/media/Files/downloads/gnu-a/8.3-2019.03/binrel/gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu.tar.xz?revision=2e88a73f-d233-4f96-b1f4-d8b36e9bb0b9&la=en' -O gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu.tar.xz
+tar xJf gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu.tar.xz -C build-aarch64/cmake/toolchain/linux-aarch64 --strip-components=1
+```
+
+## Build ClickHouse {#build-clickhouse}
+
+``` bash
+cd ClickHouse
+mkdir build-arm64
+CC=clang-13 CXX=clang++-13 cmake . -Bbuild-arm64 -DCMAKE_TOOLCHAIN_FILE=cmake/linux/toolchain-aarch64.cmake
+ninja -C build-arm64
+```
+
+The resulting binary will run only on Linux with the AARCH64 CPU architecture.
diff --git a/docs/en/reference/development/build-cross-osx.md b/docs/en/reference/development/build-cross-osx.md
new file mode 100644
index 00000000000..1dbd0ec6430
--- /dev/null
+++ b/docs/en/reference/development/build-cross-osx.md
@@ -0,0 +1,62 @@
+---
+sidebar_position: 66
+sidebar_label: Build on Linux for Mac OS X
+---
+
+# How to Build ClickHouse on Linux for Mac OS X 
+
+This is for the case when you have a Linux machine and want to use it to build `clickhouse` binary that will run on OS X. 
+This is intended for continuous integration checks that run on Linux servers. If you want to build ClickHouse directly on Mac OS X, then proceed with [another instruction](../development/build-osx.md).
+
+The cross-build for Mac OS X is based on the [Build instructions](../development/build.md), follow them first.
+
+## Install Clang-13
+
+Follow the instructions from https://apt.llvm.org/ for your Ubuntu or Debian setup.
+For example the commands for Bionic are like:
+
+``` bash
+sudo echo "deb [trusted=yes] http://apt.llvm.org/bionic/ llvm-toolchain-bionic-13 main" >> /etc/apt/sources.list
+sudo apt-get install clang-13
+```
+
+## Install Cross-Compilation Toolset {#install-cross-compilation-toolset}
+
+Let’s remember the path where we install `cctools` as ${CCTOOLS}
+
+``` bash
+mkdir ${CCTOOLS}
+cd ${CCTOOLS}
+
+git clone https://github.com/tpoechtrager/apple-libtapi.git
+cd apple-libtapi
+INSTALLPREFIX=${CCTOOLS} ./build.sh
+./install.sh
+cd ..
+
+git clone https://github.com/tpoechtrager/cctools-port.git
+cd cctools-port/cctools
+./configure --prefix=$(readlink -f ${CCTOOLS}) --with-libtapi=$(readlink -f ${CCTOOLS}) --target=x86_64-apple-darwin
+make install
+```
+
+Also, we need to download macOS X SDK into the working tree.
+
+``` bash
+cd ClickHouse
+wget 'https://github.com/phracker/MacOSX-SDKs/releases/download/10.15/MacOSX10.15.sdk.tar.xz'
+mkdir -p build-darwin/cmake/toolchain/darwin-x86_64
+tar xJf MacOSX10.15.sdk.tar.xz -C build-darwin/cmake/toolchain/darwin-x86_64 --strip-components=1
+```
+
+## Build ClickHouse {#build-clickhouse}
+
+``` bash
+cd ClickHouse
+mkdir build-darwin
+cd build-darwin
+CC=clang-13 CXX=clang++-13 cmake -DCMAKE_AR:FILEPATH=${CCTOOLS}/bin/aarch64-apple-darwin-ar -DCMAKE_INSTALL_NAME_TOOL=${CCTOOLS}/bin/aarch64-apple-darwin-install_name_tool -DCMAKE_RANLIB:FILEPATH=${CCTOOLS}/bin/aarch64-apple-darwin-ranlib -DLINKER_NAME=${CCTOOLS}/bin/aarch64-apple-darwin-ld -DCMAKE_TOOLCHAIN_FILE=cmake/darwin/toolchain-x86_64.cmake ..
+ninja
+```
+
+The resulting binary will have a Mach-O executable format and can’t be run on Linux.
diff --git a/docs/en/reference/development/build-cross-riscv.md b/docs/en/reference/development/build-cross-riscv.md
new file mode 100644
index 00000000000..94c0f47a05d
--- /dev/null
+++ b/docs/en/reference/development/build-cross-riscv.md
@@ -0,0 +1,30 @@
+---
+sidebar_position: 68
+sidebar_label: Build on Linux for RISC-V 64
+---
+
+# How to Build ClickHouse on Linux for RISC-V 64 Architecture 
+
+As of writing (11.11.2021) building for risc-v considered to be highly experimental. Not all features can be enabled.
+
+This is for the case when you have Linux machine and want to use it to build `clickhouse` binary that will run on another Linux machine with RISC-V 64 CPU architecture. This is intended for continuous integration checks that run on Linux servers.
+
+The cross-build for RISC-V 64 is based on the [Build instructions](../development/build.md), follow them first.
+
+## Install Clang-13
+
+Follow the instructions from https://apt.llvm.org/ for your Ubuntu or Debian setup or do
+```
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
+```
+
+## Build ClickHouse {#build-clickhouse}
+
+``` bash
+cd ClickHouse
+mkdir build-riscv64
+CC=clang-13 CXX=clang++-13 cmake . -Bbuild-riscv64 -G Ninja -DCMAKE_TOOLCHAIN_FILE=cmake/linux/toolchain-riscv64.cmake -DGLIBC_COMPATIBILITY=OFF -DENABLE_LDAP=OFF  -DOPENSSL_NO_ASM=ON -DENABLE_JEMALLOC=ON -DENABLE_PARQUET=OFF -DENABLE_ORC=OFF -DUSE_UNWIND=OFF -DENABLE_GRPC=OFF -DENABLE_HDFS=OFF -DENABLE_MYSQL=OFF
+ninja -C build-riscv64
+```
+
+The resulting binary will run only on Linux with the RISC-V 64 CPU architecture.
diff --git a/docs/en/reference/development/build-osx.md b/docs/en/reference/development/build-osx.md
new file mode 100644
index 00000000000..05ef10ad020
--- /dev/null
+++ b/docs/en/reference/development/build-osx.md
@@ -0,0 +1,154 @@
+---
+sidebar_position: 65
+sidebar_label: Build on Mac OS X
+description: How to build ClickHouse on Mac OS X
+---
+
+# How to Build ClickHouse on Mac OS X 
+
+:::info You don't have to build ClickHouse yourself!
+You can install pre-built ClickHouse as described in [Quick Start](https://clickhouse.com/#quick-start). Follow **macOS (Intel)** or **macOS (Apple silicon)** installation instructions.
+:::
+
+Build should work on x86_64 (Intel) and arm64 (Apple silicon) based macOS 10.15 (Catalina) and higher with Homebrew's vanilla Clang.
+It is always recommended to use vanilla `clang` compiler. 
+
+:::note
+It is possible to use XCode's `apple-clang` or `gcc`, but it's strongly discouraged.
+:::
+
+## Install Homebrew {#install-homebrew}
+
+``` bash
+/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+# ...and follow the printed instructions on any additional steps required to complete the installation.
+```
+
+## Install Xcode and Command Line Tools {#install-xcode-and-command-line-tools}
+
+Install the latest [Xcode](https://apps.apple.com/am/app/xcode/id497799835?mt=12) from App Store.
+
+Open it at least once to accept the end-user license agreement and automatically install the required components.
+
+Then, make sure that the latest Command Line Tools are installed and selected in the system:
+
+``` bash
+sudo rm -rf /Library/Developer/CommandLineTools
+sudo xcode-select --install
+```
+
+## Install Required Compilers, Tools, and Libraries {#install-required-compilers-tools-and-libraries}
+
+``` bash
+brew update
+brew install cmake ninja libtool gettext llvm gcc binutils
+```
+
+## Checkout ClickHouse Sources {#checkout-clickhouse-sources}
+
+``` bash
+git clone --recursive git@github.com:ClickHouse/ClickHouse.git
+# ...alternatively, you can use https://github.com/ClickHouse/ClickHouse.git as the repo URL.
+```
+
+## Build ClickHouse {#build-clickhouse}
+
+To build using Homebrew's vanilla Clang compiler (the only **recommended** way):
+
+``` bash
+cd ClickHouse
+rm -rf build
+mkdir build
+cd build
+cmake -DCMAKE_C_COMPILER=$(brew --prefix llvm)/bin/clang -DCMAKE_CXX_COMPILER=$(brew --prefix llvm)/bin/clang++ -DCMAKE_AR=$(brew --prefix llvm)/bin/llvm-ar -DCMAKE_RANLIB=$(brew --prefix llvm)/bin/llvm-ranlib -DOBJCOPY_PATH=$(brew --prefix llvm)/bin/llvm-objcopy -DCMAKE_BUILD_TYPE=RelWithDebInfo ..
+cmake --build . --config RelWithDebInfo
+# The resulting binary will be created at: ./programs/clickhouse
+```
+
+To build using Xcode's native AppleClang compiler in Xcode IDE (this option is only for development builds and workflows, and is **not recommended** unless you know what you are doing):
+
+``` bash
+cd ClickHouse
+rm -rf build
+mkdir build
+cd build
+XCODE_IDE=1 ALLOW_APPLECLANG=1 cmake -G Xcode -DCMAKE_BUILD_TYPE=Debug -DENABLE_JEMALLOC=OFF ..
+cmake --open .
+# ...then, in Xcode IDE select ALL_BUILD scheme and start the building process.
+# The resulting binary will be created at: ./programs/Debug/clickhouse
+```
+
+To build using Homebrew's vanilla GCC compiler (this option is only for development experiments, and is **absolutely not recommended** unless you really know what you are doing):
+
+``` bash
+cd ClickHouse
+rm -rf build
+mkdir build
+cd build
+cmake -DCMAKE_C_COMPILER=$(brew --prefix gcc)/bin/gcc-11 -DCMAKE_CXX_COMPILER=$(brew --prefix gcc)/bin/g++-11 -DCMAKE_AR=$(brew --prefix gcc)/bin/gcc-ar-11 -DCMAKE_RANLIB=$(brew --prefix gcc)/bin/gcc-ranlib-11 -DOBJCOPY_PATH=$(brew --prefix binutils)/bin/objcopy -DCMAKE_BUILD_TYPE=RelWithDebInfo ..
+cmake --build . --config RelWithDebInfo
+# The resulting binary will be created at: ./programs/clickhouse
+```
+
+## Caveats {#caveats}
+
+If you intend to run `clickhouse-server`, make sure to increase the system’s maxfiles variable.
+
+:::note    
+You’ll need to use sudo.
+:::
+
+To do so, create the `/Library/LaunchDaemons/limit.maxfiles.plist` file with the following content:
+
+``` xml
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
+        "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+  <dict>
+    <key>Label</key>
+    <string>limit.maxfiles</string>
+    <key>ProgramArguments</key>
+    <array>
+      <string>launchctl</string>
+      <string>limit</string>
+      <string>maxfiles</string>
+      <string>524288</string>
+      <string>524288</string>
+    </array>
+    <key>RunAtLoad</key>
+    <true/>
+    <key>ServiceIPC</key>
+    <false/>
+  </dict>
+</plist>
+```
+
+Give the file correct permissions:
+
+``` bash
+sudo chown root:wheel /Library/LaunchDaemons/limit.maxfiles.plist
+```
+
+Validate that the file is correct:
+
+``` bash
+plutil /Library/LaunchDaemons/limit.maxfiles.plist
+```
+
+Load the file (or reboot):
+
+``` bash
+sudo launchctl load -w /Library/LaunchDaemons/limit.maxfiles.plist
+```
+
+To check if it’s working, use the `ulimit -n` or `launchctl limit maxfiles` commands.
+
+## Running ClickHouse server
+
+``` bash
+cd ClickHouse
+./build/programs/clickhouse-server --config-file ./programs/server/config.xml
+```
+
+[Original article](https://clickhouse.com/docs/en/development/build_osx/) <!--hide-->
diff --git a/docs/en/reference/development/build.md b/docs/en/reference/development/build.md
new file mode 100644
index 00000000000..b128412a55e
--- /dev/null
+++ b/docs/en/reference/development/build.md
@@ -0,0 +1,181 @@
+---
+sidebar_position: 64
+sidebar_label: Build on Linux
+description: How to build ClickHouse on Linux
+---
+
+# How to Build ClickHouse on Linux
+
+Supported platforms:
+
+-   x86_64
+-   AArch64
+-   Power9 (experimental)
+
+## Normal Build for Development on Ubuntu
+
+The following tutorial is based on the Ubuntu Linux system. With appropriate changes, it should also work on any other Linux distribution.
+
+### Install Git, CMake, Python and Ninja {#install-git-cmake-python-and-ninja}
+
+``` bash
+$ sudo apt-get install git cmake python ninja-build
+```
+
+Or cmake3 instead of cmake on older systems.
+
+### Install the latest clang (recommended)
+
+On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
+
+```bash
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
+```
+
+For other Linux distribution - check the availability of the [prebuild packages](https://releases.llvm.org/download.html) or build clang [from sources](https://clang.llvm.org/get_started.html).
+
+#### Use the latest clang for Builds
+
+``` bash
+$ export CC=clang-14
+$ export CXX=clang++-14
+```
+
+In this example we use version 14 that is the latest as of Feb 2022.
+
+Gcc can also be used though it is discouraged.
+
+### Checkout ClickHouse Sources {#checkout-clickhouse-sources}
+
+``` bash
+$ git clone --recursive git@github.com:ClickHouse/ClickHouse.git
+```
+
+or
+
+``` bash
+$ git clone --recursive https://github.com/ClickHouse/ClickHouse.git
+```
+
+### Build ClickHouse {#build-clickhouse}
+
+``` bash
+$ cd ClickHouse
+$ mkdir build
+$ cd build
+$ cmake ..
+$ ninja
+```
+
+To create an executable, run `ninja clickhouse`.
+This will create the `programs/clickhouse` executable, which can be used with `client` or `server` arguments.
+
+## How to Build ClickHouse on Any Linux {#how-to-build-clickhouse-on-any-linux}
+
+The build requires the following components:
+
+-   Git (is used only to checkout the sources, it’s not needed for the build)
+-   CMake 3.10 or newer
+-   Ninja
+-   C++ compiler: clang-13 or newer
+-   Linker: lld
+
+If all the components are installed, you may build in the same way as the steps above.
+
+Example for Ubuntu Eoan:
+``` bash
+sudo apt update
+sudo apt install git cmake ninja-build clang++ python
+git clone --recursive https://github.com/ClickHouse/ClickHouse.git
+mkdir build && cd build
+cmake ../ClickHouse
+ninja
+```
+
+Example for OpenSUSE Tumbleweed:
+``` bash
+sudo zypper install git cmake ninja clang-c++ python lld
+git clone --recursive https://github.com/ClickHouse/ClickHouse.git
+mkdir build && cd build
+cmake ../ClickHouse
+ninja
+```
+
+Example for Fedora Rawhide:
+``` bash
+sudo yum update
+yum --nogpg install git cmake make clang-c++ python3
+git clone --recursive https://github.com/ClickHouse/ClickHouse.git
+mkdir build && cd build
+cmake ../ClickHouse
+make -j $(nproc)
+```
+
+Here is an example of how to build `clang` and all the llvm infrastructure from sources:
+
+```
+ git clone git@github.com:llvm/llvm-project.git
+ mkdir llvm-build && cd llvm-build
+ cmake -DCMAKE_BUILD_TYPE:STRING=Release -DLLVM_ENABLE_PROJECTS=all ../llvm-project/llvm/
+ make -j16
+ sudo make install
+ hash clang
+ clang --version
+```
+
+You can install the older clang like clang-11 from packages and then use it to build the new clang from sources.
+
+Here is an example of how to install the new `cmake` from the official website:
+
+```
+wget https://github.com/Kitware/CMake/releases/download/v3.22.2/cmake-3.22.2-linux-x86_64.sh
+chmod +x cmake-3.22.2-linux-x86_64.sh
+./cmake-3.22.2-linux-x86_64.sh 
+export PATH=/home/milovidov/work/cmake-3.22.2-linux-x86_64/bin/:${PATH}
+hash cmake
+```
+
+## How to Build ClickHouse Debian Package {#how-to-build-clickhouse-debian-package}
+
+### Install Git {#install-git}
+
+``` bash
+$ sudo apt-get update
+$ sudo apt-get install git python debhelper lsb-release fakeroot sudo debian-archive-keyring debian-keyring
+```
+
+### Checkout ClickHouse Sources {#checkout-clickhouse-sources-1}
+
+``` bash
+$ git clone --recursive --branch master https://github.com/ClickHouse/ClickHouse.git
+$ cd ClickHouse
+```
+
+### Run Release Script {#run-release-script}
+
+``` bash
+$ ./release
+```
+
+## You Don’t Have to Build ClickHouse {#you-dont-have-to-build-clickhouse}
+
+ClickHouse is available in pre-built binaries and packages. Binaries are portable and can be run on any Linux flavour.
+
+They are built for stable, prestable and testing releases as long as for every commit to master and for every pull request.
+
+To find the freshest build from `master`, go to [commits page](https://github.com/ClickHouse/ClickHouse/commits/master), click on the first green checkmark or red cross near commit, and click to the “Details” link right after “ClickHouse Build Check”.
+
+## Faster builds for development: Split build configuration {#split-build}
+
+Normally, ClickHouse is statically linked into a single static `clickhouse` binary with minimal dependencies. This is convenient for distribution, but it means that on every change the entire binary needs to be linked, which is slow and may be inconvenient for development. There is an alternative configuration which instead creates dynamically loaded shared libraries and separate binaries `clickhouse-server`, `clickhouse-client` etc., allowing for faster incremental builds. To use it, add the following flags to your `cmake` invocation:
+```
+-DUSE_STATIC_LIBRARIES=0 -DSPLIT_SHARED_LIBRARIES=1 -DCLICKHOUSE_SPLIT_BINARY=1
+```
+
+Note that the split build has several drawbacks:
+* There is no single `clickhouse` binary, and you have to run `clickhouse-server`, `clickhouse-client`, etc.
+* Risk of segfault if you run any of the programs while rebuilding the project.
+* You cannot run the integration tests since they only work a single complete binary.
+* You can't easily copy the binaries elsewhere. Instead of moving a single binary you'll need to copy all binaries and libraries.
+
+[Original article](https://clickhouse.com/docs/en/development/build/) <!--hide-->
diff --git a/docs/en/reference/development/continuous-integration.md b/docs/en/reference/development/continuous-integration.md
new file mode 100644
index 00000000000..b3172d103f0
--- /dev/null
+++ b/docs/en/reference/development/continuous-integration.md
@@ -0,0 +1,193 @@
+---
+sidebar_position: 62
+sidebar_label: Continuous Integration Checks
+description: When you submit a pull request, some automated checks are ran for your code by the ClickHouse continuous integration (CI) system
+---
+
+# Continuous Integration Checks
+
+When you submit a pull request, some automated checks are ran for your code by
+the ClickHouse [continuous integration (CI) system](tests.md#test-automation).
+This happens after a repository maintainer (someone from ClickHouse team) has
+screened your code and added the `can be tested` label to your pull request.
+The results of the checks are listed on the GitHub pull request page as
+described in the [GitHub checks
+documentation](https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests/about-status-checks).
+If a check is failing, you might be required to fix it. This page gives an
+overview of checks you may encounter, and what you can do to fix them.
+
+If it looks like the check failure is not related to your changes, it may be
+some transient failure or an infrastructure problem. Push an empty commit to
+the pull request to restart the CI checks:
+```
+git reset
+git commit --allow-empty
+git push
+```
+
+If you are not sure what to do, ask a maintainer for help.
+
+
+## Merge With Master
+
+Verifies that the PR can be merged to master. If not, it will fail with the
+message 'Cannot fetch mergecommit'. To fix this check, resolve the conflict as
+described in the [GitHub
+documentation](https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests/resolving-a-merge-conflict-on-github),
+or merge the `master` branch to your pull request branch using git.
+
+
+## Docs check
+
+Tries to build the ClickHouse documentation website. It can fail if you changed
+something in the documentation. Most probable reason is that some cross-link in
+the documentation is wrong. Go to the check report and look for `ERROR` and `WARNING` messages.
+
+### Report Details
+
+- [Status page example](https://clickhouse-test-reports.s3.yandex.net/12550/eabcc293eb02214caa6826b7c15f101643f67a6b/docs_check.html)
+- `docs_output.txt` contains the building log. [Successful result example](https://clickhouse-test-reports.s3.yandex.net/12550/eabcc293eb02214caa6826b7c15f101643f67a6b/docs_check/docs_output.txt)
+
+
+## Description Check
+
+Check that the description of your pull request conforms to the template
+[PULL_REQUEST_TEMPLATE.md](https://github.com/ClickHouse/ClickHouse/blob/master/.github/PULL_REQUEST_TEMPLATE.md).
+You have to specify a changelog category for your change (e.g., Bug Fix), and
+write a user-readable message describing the change for [CHANGELOG.md](../whats-new/changelog/index.md)
+
+
+## Push To Dockerhub
+
+Builds docker images used for build and tests, then pushes them to DockerHub.
+
+
+## Marker Check
+
+This check means that the CI system started to process the pull request. When it has 'pending' status, it means that not all checks have been started yet. After all checks have been started, it changes status to 'success'.
+
+
+## Style Check
+
+Performs some simple regex-based checks of code style, using the [`utils/check-style/check-style`](https://github.com/ClickHouse/ClickHouse/blob/master/utils/check-style/check-style) binary (note that it can be run locally).
+If it fails, fix the style errors following the [code style guide](style.md).
+
+### Report Details
+- [Status page example](https://clickhouse-test-reports.s3.yandex.net/12550/659c78c7abb56141723af6a81bfae39335aa8cb2/style_check.html)
+- `output.txt` contains the check resulting errors (invalid tabulation etc), blank page means no errors. [Successful result example](https://clickhouse-test-reports.s3.yandex.net/12550/659c78c7abb56141723af6a81bfae39335aa8cb2/style_check/output.txt).
+
+
+## Fast Test
+Normally this is the first check that is ran for a PR. It builds ClickHouse and
+runs most of [stateless functional tests](tests.md#functional-tests), omitting
+some. If it fails, further checks are not started until it is fixed. Look at
+the report to see which tests fail, then reproduce the failure locally as
+described [here](tests.md#functional-test-locally).
+
+### Report Details
+[Status page example](https://clickhouse-test-reports.s3.yandex.net/12550/67d716b5cc3987801996c31a67b31bf141bc3486/fast_test.html)
+
+#### Status Page Files
+- `runlog.out.log` is the general log that includes all other logs.
+- `test_log.txt`
+- `submodule_log.txt` contains the messages about cloning and checkouting needed submodules.
+- `stderr.log`
+- `stdout.log`
+- `clickhouse-server.log`
+- `clone_log.txt`
+- `install_log.txt`
+- `clickhouse-server.err.log`
+- `build_log.txt`
+- `cmake_log.txt` contains messages about the C/C++ and Linux flags check.
+
+#### Status Page Columns
+
+- *Test name* contains the name of the test (without the path e.g. all types of tests will be stripped to the name).
+- *Test status* -- one of _Skipped_, _Success_, or _Fail_.
+- *Test time, sec.* -- empty on this test.
+
+
+## Build Check {#build-check}
+
+Builds ClickHouse in various configurations for use in further steps. You have to fix the builds that fail. Build logs often has enough information to fix the error, but you might have to reproduce the failure locally. The `cmake` options can be found in the build log, grepping for `cmake`. Use these options and follow the [general build process](../development/build.md).
+
+### Report Details
+
+[Status page example](https://clickhouse-builds.s3.yandex.net/12550/67d716b5cc3987801996c31a67b31bf141bc3486/clickhouse_build_check/report.html).
+
+- **Compiler**: `gcc-9` or `clang-10` (or `clang-10-xx` for other architectures e.g. `clang-10-freebsd`).
+- **Build type**: `Debug` or `RelWithDebInfo` (cmake).
+- **Sanitizer**: `none` (without sanitizers), `address` (ASan), `memory` (MSan), `undefined` (UBSan), or `thread` (TSan).
+- **Splitted** `splitted` is a [split build](../development/build.md#split-build)
+- **Status**: `success` or `fail`
+- **Build log**: link to the building and files copying log, useful when build failed.
+- **Build time**.
+- **Artifacts**: build result files (with `XXX` being the server version e.g. `20.8.1.4344`).
+  - `clickhouse-client_XXX_all.deb`
+  - `clickhouse-common-static-dbg_XXX[+asan, +msan, +ubsan, +tsan]_amd64.deb`
+  - `clickhouse-common-staticXXX_amd64.deb`
+  - `clickhouse-server_XXX_all.deb`
+  - `clickhouse_XXX_amd64.buildinfo`
+  - `clickhouse_XXX_amd64.changes`
+  - `clickhouse`: Main built binary.
+  - `clickhouse-odbc-bridge`
+  - `unit_tests_dbms`: GoogleTest binary with ClickHouse unit tests.
+  - `shared_build.tgz`: build with shared libraries.
+  - `performance.tgz`: Special package for performance tests.
+
+
+## Special Build Check
+Performs static analysis and code style checks using `clang-tidy`. The report is similar to the [build check](#build-check). Fix the errors found in the build log.
+
+
+## Functional Stateless Tests
+Runs [stateless functional tests](tests.md#functional-tests) for ClickHouse
+binaries built in various configurations -- release, debug, with sanitizers,
+etc. Look at the report to see which tests fail, then reproduce the failure
+locally as described [here](tests.md#functional-test-locally). Note that you
+have to use the correct build configuration to reproduce -- a test might fail
+under AddressSanitizer but pass in Debug. Download the binary from [CI build
+checks page](../development/build.md#you-dont-have-to-build-clickhouse), or build it locally.
+
+
+## Functional Stateful Tests
+Runs [stateful functional tests](tests.md#functional-tests). Treat them in the same way as the functional stateless tests. The difference is that they require `hits` and `visits` tables from the [clickstream dataset](../example-datasets/metrica.md) to run.
+
+
+## Integration Tests
+Runs [integration tests](tests.md#integration-tests).
+
+
+## Testflows Check
+Runs some tests using Testflows test system. See [here](https://github.com/ClickHouse/ClickHouse/tree/master/tests/testflows#running-tests-locally) how to run them locally.
+
+
+## Stress Test
+Runs stateless functional tests concurrently from several clients to detect
+concurrency-related errors. If it fails:
+
+    * Fix all other test failures first;
+    * Look at the report to find the server logs and check them for possible causes
+      of error.
+
+
+## Split Build Smoke Test
+
+Checks that the server build in [split build](../development/build.md#split-build)
+configuration can start and run simple queries.  If it fails:
+
+    * Fix other test errors first;
+    * Build the server in [split build](../development/build.md#split-build) configuration
+      locally and check whether it can start and run `select 1`.
+
+
+## Compatibility Check
+Checks that `clickhouse` binary runs on distributions with old libc versions. If it fails, ask a maintainer for help.
+
+
+## AST Fuzzer
+Runs randomly generated queries to catch program errors. If it fails, ask a maintainer for help.
+
+
+## Performance Tests
+Measure changes in query performance. This is the longest check that takes just below 6 hours to run. The performance test report is described in detail [here](https://github.com/ClickHouse/ClickHouse/tree/master/docker/test/performance-comparison#how-to-read-the-report).
diff --git a/docs/en/reference/development/contrib.md b/docs/en/reference/development/contrib.md
new file mode 100644
index 00000000000..7cbe32fdd8b
--- /dev/null
+++ b/docs/en/reference/development/contrib.md
@@ -0,0 +1,107 @@
+---
+sidebar_position: 71
+sidebar_label: Third-Party Libraries
+description: A list of third-party libraries used 
+---
+
+# Third-Party Libraries Used 
+
+The list of third-party libraries:
+
+| Library name | License type |
+|:-|:-|
+| abseil-cpp | [Apache](https://github.com/ClickHouse-Extras/abseil-cpp/blob/4f3b686f86c3ebaba7e4e926e62a79cb1c659a54/LICENSE) |
+| AMQP-CPP | [Apache](https://github.com/ClickHouse-Extras/AMQP-CPP/blob/1a6c51f4ac51ac56610fa95081bd2f349911375a/LICENSE) |
+| arrow | [Apache](https://github.com/ClickHouse-Extras/arrow/blob/078e21bad344747b7656ef2d7a4f7410a0a303eb/LICENSE.txt) |
+| avro | [Apache](https://github.com/ClickHouse-Extras/avro/blob/e43c46e87fd32eafdc09471e95344555454c5ef8/LICENSE.txt) |
+| aws | [Apache](https://github.com/ClickHouse-Extras/aws-sdk-cpp/blob/7d48b2c8193679cc4516e5bd68ae4a64b94dae7d/LICENSE.txt) |
+| aws-c-common | [Apache](https://github.com/ClickHouse-Extras/aws-c-common/blob/736a82d1697c108b04a277e66438a7f4e19b6857/LICENSE) |
+| aws-c-event-stream | [Apache](https://github.com/ClickHouse-Extras/aws-c-event-stream/blob/3bc33662f9ccff4f4cbcf9509cc78c26e022fde0/LICENSE) |
+| aws-checksums | [Apache](https://github.com/ClickHouse-Extras/aws-checksums/blob/519d6d9093819b6cf89ffff589a27ef8f83d0f65/LICENSE) |
+| base64 | [BSD 2-clause](https://github.com/ClickHouse-Extras/Turbo-Base64/blob/af9b331f2b4f30b41c70f3a571ff904a8251c1d3/LICENSE) |
+| boost | [Boost](https://github.com/ClickHouse-Extras/boost/blob/9cf09dbfd55a5c6202dedbdf40781a51b02c2675/LICENSE_1_0.txt) |
+| boringssl | [BSD](https://github.com/ClickHouse-Extras/boringssl/blob/a6a2e2ab3e44d97ce98e51c558e989f211de7eb3/LICENSE) |
+| brotli | [MIT](https://github.com/google/brotli/blob/63be8a99401992075c23e99f7c84de1c653e39e2/LICENSE) |
+| capnproto | [MIT](https://github.com/capnproto/capnproto/blob/a00ccd91b3746ef2ab51d40fe3265829949d1ace/LICENSE) |
+| cassandra | [Apache](https://github.com/ClickHouse-Extras/cpp-driver/blob/eb9b68dadbb4417a2c132ad4a1c2fa76e65e6fc1/LICENSE.txt) |
+| cctz | [Apache](https://github.com/ClickHouse-Extras/cctz/blob/c0f1bcb97fd2782f7c3f972fadd5aad5affac4b8/LICENSE.txt) |
+| cityhash102 | [MIT](https://github.com/ClickHouse/ClickHouse/blob/master/contrib/cityhash102/COPYING) |
+| cppkafka | [BSD 2-clause](https://github.com/mfontanini/cppkafka/blob/5a119f689f8a4d90d10a9635e7ee2bee5c127de1/LICENSE) |
+| croaring | [Apache](https://github.com/RoaringBitmap/CRoaring/blob/2c867e9f9c9e2a3a7032791f94c4c7ae3013f6e0/LICENSE) |
+| curl | [Apache](https://github.com/curl/curl/blob/3b8bbbbd1609c638a3d3d0acb148a33dedb67be3/docs/LICENSE-MIXING.md) |
+| cyrus-sasl | [BSD 2-clause](https://github.com/ClickHouse-Extras/cyrus-sasl/blob/e6466edfd638cc5073debe941c53345b18a09512/COPYING) |
+| double-conversion | [BSD 3-clause](https://github.com/google/double-conversion/blob/cf2f0f3d547dc73b4612028a155b80536902ba02/LICENSE) |
+| dragonbox | [Apache](https://github.com/ClickHouse-Extras/dragonbox/blob/923705af6fd953aa948fc175f6020b15f7359838/LICENSE-Apache2-LLVM) |
+| fast_float | [Apache](https://github.com/fastfloat/fast_float/blob/7eae925b51fd0f570ccd5c880c12e3e27a23b86f/LICENSE) |
+| fastops | [MIT](https://github.com/ClickHouse-Extras/fastops/blob/88752a5e03cf34639a4a37a4b41d8b463fffd2b5/LICENSE) |
+| flatbuffers | [Apache](https://github.com/ClickHouse-Extras/flatbuffers/blob/eb3f827948241ce0e701516f16cd67324802bce9/LICENSE.txt) |
+| fmtlib | [Unknown](https://github.com/fmtlib/fmt/blob/c108ee1d590089ccf642fc85652b845924067af2/LICENSE.rst) |
+| gcem | [Apache](https://github.com/kthohr/gcem/blob/8d4f1b5d76ea8f6ff12f3f4f34cda45424556b00/LICENSE) |
+| googletest | [BSD 3-clause](https://github.com/google/googletest/blob/e7e591764baba0a0c3c9ad0014430e7a27331d16/LICENSE) |
+| grpc | [Apache](https://github.com/ClickHouse-Extras/grpc/blob/60c986e15cae70aade721d26badabab1f822fdd6/LICENSE) |
+| h3 | [Apache](https://github.com/ClickHouse-Extras/h3/blob/c7f46cfd71fb60e2fefc90e28abe81657deff735/LICENSE) |
+| hyperscan | [Boost](https://github.com/ClickHouse-Extras/hyperscan/blob/e9f08df0213fc637aac0a5bbde9beeaeba2fe9fa/LICENSE) |
+| icu | [Public Domain](https://github.com/unicode-org/icu/blob/a56dde820dc35665a66f2e9ee8ba58e75049b668/icu4c/LICENSE) |
+| icudata | [Public Domain](https://github.com/ClickHouse-Extras/icudata/blob/72d9a4a7febc904e2b0a534ccb25ae40fac5f1e5/LICENSE) |
+| jemalloc | [BSD 2-clause](https://github.com/ClickHouse-Extras/jemalloc/blob/e6891d9746143bf2cf617493d880ba5a0b9a3efd/COPYING) |
+| krb5 | [MIT](https://github.com/ClickHouse-Extras/krb5/blob/5149dea4e2be0f67707383d2682b897c14631374/src/lib/gssapi/LICENSE) |
+| libc-headers | [LGPL](https://github.com/ClickHouse-Extras/libc-headers/blob/a720b7105a610acbd7427eea475a5b6810c151eb/LICENSE) |
+| libcpuid | [BSD 2-clause](https://github.com/ClickHouse-Extras/libcpuid/blob/8db3b8d2d32d22437f063ce692a1b9bb15e42d18/COPYING) |
+| libcxx | [Apache](https://github.com/ClickHouse-Extras/libcxx/blob/2fa892f69acbaa40f8a18c6484854a6183a34482/LICENSE.TXT) |
+| libcxxabi | [Apache](https://github.com/ClickHouse-Extras/libcxxabi/blob/df8f1e727dbc9e2bedf2282096fa189dc3fe0076/LICENSE.TXT) |
+| libdivide | [zLib](https://github.com/ClickHouse/ClickHouse/blob/master/contrib/libdivide/LICENSE.txt) |
+| libfarmhash | [MIT](https://github.com/ClickHouse/ClickHouse/blob/master/contrib/libfarmhash/COPYING) |
+| libgsasl | [LGPL](https://github.com/ClickHouse-Extras/libgsasl/blob/383ee28e82f69fa16ed43b48bd9c8ee5b313ab84/LICENSE) |
+| libhdfs3 | [Apache](https://github.com/ClickHouse-Extras/libhdfs3/blob/095b9d48b400abb72d967cb0539af13b1e3d90cf/LICENSE.txt) |
+| libmetrohash | [Apache](https://github.com/ClickHouse/ClickHouse/blob/master/contrib/libmetrohash/LICENSE) |
+| libpq | [Unknown](https://github.com/ClickHouse-Extras/libpq/blob/e071ea570f8985aa00e34f5b9d50a3cfe666327e/COPYRIGHT) |
+| libpqxx | [BSD 3-clause](https://github.com/ClickHouse-Extras/libpqxx/blob/357608d11b7a1961c3fb7db2ef9a5dbb2e87da77/COPYING) |
+| librdkafka | [MIT](https://github.com/ClickHouse-Extras/librdkafka/blob/b8554f1682062c85ba519eb54ef2f90e02b812cb/LICENSE.murmur2) |
+| libunwind | [Apache](https://github.com/ClickHouse-Extras/libunwind/blob/6b816d2fba3991f8fd6aaec17d92f68947eab667/LICENSE.TXT) |
+| libuv | [BSD](https://github.com/ClickHouse-Extras/libuv/blob/e2e9b7e9f978ce8a1367b5fe781d97d1ce9f94ab/LICENSE) |
+| llvm | [Apache](https://github.com/ClickHouse-Extras/llvm/blob/e5751459412bce1391fb7a2e9bbc01e131bf72f1/llvm/LICENSE.TXT) |
+| lz4 | [BSD](https://github.com/lz4/lz4/blob/f39b79fb02962a1cd880bbdecb6dffba4f754a11/LICENSE) |
+| mariadb-connector-c | [LGPL](https://github.com/ClickHouse-Extras/mariadb-connector-c/blob/5f4034a3a6376416504f17186c55fe401c6d8e5e/COPYING.LIB) |
+| miniselect | [Boost](https://github.com/danlark1/miniselect/blob/be0af6bd0b6eb044d1acc4f754b229972d99903a/LICENSE_1_0.txt) |
+| msgpack-c | [Boost](https://github.com/msgpack/msgpack-c/blob/46684265d50b5d1b062d4c5c428ba08462844b1d/LICENSE_1_0.txt) |
+| murmurhash | [Public Domain](https://github.com/ClickHouse/ClickHouse/blob/master/contrib/murmurhash/LICENSE) |
+| NuRaft | [Apache](https://github.com/ClickHouse-Extras/NuRaft/blob/7ecb16844af6a9c283ad432d85ecc2e7d1544676/LICENSE) |
+| openldap | [Unknown](https://github.com/ClickHouse-Extras/openldap/blob/0208811b6043ca06fda8631a5e473df1ec515ccb/LICENSE) |
+| orc | [Apache](https://github.com/ClickHouse-Extras/orc/blob/0a936f6bbdb9303308973073f8623b5a8d82eae1/LICENSE) |
+| poco | [Boost](https://github.com/ClickHouse-Extras/poco/blob/7351c4691b5d401f59e3959adfc5b4fa263b32da/LICENSE) |
+| protobuf | [BSD 3-clause](https://github.com/ClickHouse-Extras/protobuf/blob/75601841d172c73ae6bf4ce8121f42b875cdbabd/LICENSE) |
+| rapidjson | [MIT](https://github.com/ClickHouse-Extras/rapidjson/blob/c4ef90ccdbc21d5d5a628d08316bfd301e32d6fa/bin/jsonschema/LICENSE) |
+| re2 | [BSD 3-clause](https://github.com/google/re2/blob/13ebb377c6ad763ca61d12dd6f88b1126bd0b911/LICENSE) |
+| replxx | [BSD 3-clause](https://github.com/ClickHouse-Extras/replxx/blob/c81be6c68b146f15f2096b7ef80e3f21fe27004c/LICENSE.md) |
+| rocksdb | [BSD 3-clause](https://github.com/ClickHouse-Extras/rocksdb/blob/b6480c69bf3ab6e298e0d019a07fd4f69029b26a/LICENSE.leveldb) |
+| s2geometry | [Apache](https://github.com/ClickHouse-Extras/s2geometry/blob/20ea540d81f4575a3fc0aea585aac611bcd03ede/LICENSE) |
+| sentry-native | [MIT](https://github.com/ClickHouse-Extras/sentry-native/blob/94644e92f0a3ff14bd35ed902a8622a2d15f7be4/LICENSE) |
+| simdjson | [Apache](https://github.com/simdjson/simdjson/blob/8df32cea3359cb30120795da6020b3b73da01d38/LICENSE) |
+| snappy | [Public Domain](https://github.com/google/snappy/blob/3f194acb57e0487531c96b97af61dcbd025a78a3/COPYING) |
+| sparsehash-c11 | [BSD 3-clause](https://github.com/sparsehash/sparsehash-c11/blob/cf0bffaa456f23bc4174462a789b90f8b6f5f42f/LICENSE) |
+| stats | [Apache](https://github.com/kthohr/stats/blob/b6dd459c10a88c7ea04693c007e9e35820c5d9ad/LICENSE) |
+| thrift | [Apache](https://github.com/apache/thrift/blob/010ccf0a0c7023fea0f6bf4e4078ebdff7e61982/LICENSE) |
+| unixodbc | [LGPL](https://github.com/ClickHouse-Extras/UnixODBC/blob/b0ad30f7f6289c12b76f04bfb9d466374bb32168/COPYING) |
+| xz | [Public Domain](https://github.com/xz-mirror/xz/blob/869b9d1b4edd6df07f819d360d306251f8147353/COPYING) |
+| zlib-ng | [zLib](https://github.com/ClickHouse-Extras/zlib-ng/blob/6a5e93b9007782115f7f7e5235dedc81c4f1facb/LICENSE.md) |
+| zstd | [BSD](https://github.com/facebook/zstd/blob/a488ba114ec17ea1054b9057c26a046fc122b3b6/LICENSE) |
+
+The list of third-party libraries can be obtained by the following query:
+
+``` sql
+SELECT library_name, license_type, license_path FROM system.licenses ORDER BY library_name COLLATE 'en';
+```
+
+[Example](https://gh-api.clickhouse.com/play?user=play#U0VMRUNUIGxpYnJhcnlfbmFtZSwgbGljZW5zZV90eXBlLCBsaWNlbnNlX3BhdGggRlJPTSBzeXN0ZW0ubGljZW5zZXMgT1JERVIgQlkgbGlicmFyeV9uYW1lIENPTExBVEUgJ2VuJw==)
+
+## Guidelines for adding new third-party libraries and maintaining custom changes in them {#adding-third-party-libraries}
+
+1. All external third-party code should reside in the dedicated directories under `contrib` directory of ClickHouse repo. Prefer Git submodules, when available.
+2. Fork/mirror the official repo in [Clickhouse-extras](https://github.com/ClickHouse-Extras). Prefer official GitHub repos, when available.
+3. Branch from the branch you want to integrate, e.g., `master` -> `clickhouse/master`, or `release/vX.Y.Z` -> `clickhouse/release/vX.Y.Z`.
+4. All forks in [Clickhouse-extras](https://github.com/ClickHouse-Extras) can be automatically synchronized with upstreams. `clickhouse/...` branches will remain unaffected, since virtually nobody is going to use that naming pattern in their upstream repos.
+5. Add submodules under `contrib` of ClickHouse repo that refer the above forks/mirrors. Set the submodules to track the corresponding `clickhouse/...` branches.
+6. Every time the custom changes have to be made in the library code, a dedicated branch should be created, like `clickhouse/my-fix`. Then this branch should be merged into the branch, that is tracked by the submodule, e.g., `clickhouse/master` or `clickhouse/release/vX.Y.Z`.
+7. No code should be pushed in any branch of the forks in [Clickhouse-extras](https://github.com/ClickHouse-Extras), whose names do not follow `clickhouse/...` pattern.
+8. Always write the custom changes with the official repo in mind. Once the PR is merged from (a feature/fix branch in) your personal fork into the fork in [Clickhouse-extras](https://github.com/ClickHouse-Extras), and the submodule is bumped in ClickHouse repo, consider opening another PR from (a feature/fix branch in) the fork in [Clickhouse-extras](https://github.com/ClickHouse-Extras) to the official repo of the library. This will make sure, that 1) the contribution has more than a single use case and importance, 2) others will also benefit from it, 3) the change will not remain a maintenance burden solely on ClickHouse developers.
+9. When a submodule needs to start using a newer code from the original branch (e.g., `master`), and since the custom changes might be merged in the branch it is tracking (e.g., `clickhouse/master`) and so it may diverge from its original counterpart (i.e., `master`), a careful merge should be carried out first, i.e., `master` -> `clickhouse/master`, and only then the submodule can be bumped in ClickHouse.
diff --git a/docs/en/reference/development/developer-instruction.md b/docs/en/reference/development/developer-instruction.md
new file mode 100644
index 00000000000..291e57fef66
--- /dev/null
+++ b/docs/en/reference/development/developer-instruction.md
@@ -0,0 +1,278 @@
+---
+sidebar_position: 61
+sidebar_label: Getting Started
+description: Prerequisites and an overview of how to build ClickHouse
+---
+
+# Getting Started Guide for Building ClickHouse
+
+The building of ClickHouse is supported on Linux, FreeBSD and Mac OS X.
+
+If you use Windows, you need to create a virtual machine with Ubuntu. To start working with a virtual machine please install VirtualBox. You can download Ubuntu from the website: https://www.ubuntu.com/#download. Please create a virtual machine from the downloaded image (you should reserve at least 4GB of RAM for it). To run a command-line terminal in Ubuntu, please locate a program containing the word “terminal” in its name (gnome-terminal, konsole etc.) or just press Ctrl+Alt+T.
+
+ClickHouse cannot work or build on a 32-bit system. You should acquire access to a 64-bit system and you can continue reading.
+
+## Creating a Repository on GitHub {#creating-a-repository-on-github}
+
+To start working with ClickHouse repository you will need a GitHub account.
+
+You probably already have one, but if you do not, please register at https://github.com. In case you do not have SSH keys, you should generate them and then upload them on GitHub. It is required for sending over your patches. It is also possible to use the same SSH keys that you use with any other SSH servers - probably you already have those.
+
+Create a fork of ClickHouse repository. To do that please click on the “fork” button in the upper right corner at https://github.com/ClickHouse/ClickHouse. It will fork your own copy of ClickHouse/ClickHouse to your account.
+
+The development process consists of first committing the intended changes into your fork of ClickHouse and then creating a “pull request” for these changes to be accepted into the main repository (ClickHouse/ClickHouse).
+
+To work with git repositories, please install `git`.
+
+To do that in Ubuntu you would run in the command line terminal:
+
+    sudo apt update
+    sudo apt install git
+
+A brief manual on using Git can be found here: https://education.github.com/git-cheat-sheet-education.pdf.
+For a detailed manual on Git see https://git-scm.com/book/en/v2.
+
+## Cloning a Repository to Your Development Machine {#cloning-a-repository-to-your-development-machine}
+
+Next, you need to download the source files onto your working machine. This is called “to clone a repository” because it creates a local copy of the repository on your working machine.
+
+In the command line terminal run:
+
+    git clone --recursive git@github.com:your_github_username/ClickHouse.git
+    cd ClickHouse
+
+Note: please, substitute *your_github_username* with what is appropriate!
+
+This command will create a directory `ClickHouse` containing the working copy of the project.
+
+It is important that the path to the working directory contains no whitespaces as it may lead to problems with running the build system.
+
+Please note that ClickHouse repository uses `submodules`. That is what the references to additional repositories are called (i.e. external libraries on which the project depends). It means that when cloning the repository you need to specify the `--recursive` flag as in the example above. If the repository has been cloned without submodules, to download them you need to run the following:
+
+    git submodule init
+    git submodule update
+
+You can check the status with the command: `git submodule status`.
+
+If you get the following error message:
+
+    Permission denied (publickey).
+    fatal: Could not read from remote repository.
+
+    Please make sure you have the correct access rights
+    and the repository exists.
+
+It generally means that the SSH keys for connecting to GitHub are missing. These keys are normally located in `~/.ssh`. For SSH keys to be accepted you need to upload them in the settings section of GitHub UI.
+
+You can also clone the repository via https protocol:
+
+    git clone --recursive https://github.com/ClickHouse/ClickHouse.git
+
+This, however, will not let you send your changes to the server. You can still use it temporarily and add the SSH keys later replacing the remote address of the repository with `git remote` command.
+
+You can also add original ClickHouse repo’s address to your local repository to pull updates from there:
+
+    git remote add upstream git@github.com:ClickHouse/ClickHouse.git
+
+After successfully running this command you will be able to pull updates from the main ClickHouse repo by running `git pull upstream master`.
+
+### Working with Submodules {#working-with-submodules}
+
+Working with submodules in git could be painful. Next commands will help to manage it:
+
+    # ! each command accepts
+    # Update remote URLs for submodules. Barely rare case
+    git submodule sync
+    # Add new submodules
+    git submodule init
+    # Update existing submodules to the current state
+    git submodule update
+    # Two last commands could be merged together
+    git submodule update --init
+
+The next commands would help you to reset all submodules to the initial state (!WARNING! - any changes inside will be deleted):
+
+    # Synchronizes submodules' remote URL with .gitmodules
+    git submodule sync
+    # Update the registered submodules with initialize not yet initialized
+    git submodule update --init
+    # Reset all changes done after HEAD
+    git submodule foreach git reset --hard
+    # Clean files from .gitignore
+    git submodule foreach git clean -xfd
+    # Repeat last 4 commands for all submodule
+    git submodule foreach git submodule sync
+    git submodule foreach git submodule update --init
+    git submodule foreach git submodule foreach git reset --hard
+    git submodule foreach git submodule foreach git clean -xfd
+
+## Build System {#build-system}
+
+ClickHouse uses CMake and Ninja for building.
+
+CMake - a meta-build system that can generate Ninja files (build tasks).
+Ninja - a smaller build system with a focus on the speed used to execute those cmake generated tasks.
+
+To install on Ubuntu, Debian or Mint run `sudo apt install cmake ninja-build`.
+
+On CentOS, RedHat run `sudo yum install cmake ninja-build`.
+
+If you use Arch or Gentoo, you probably know it yourself how to install CMake.
+
+For installing CMake and Ninja on Mac OS X first install Homebrew and then install everything else via brew:
+
+    /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
+    brew install cmake ninja
+
+Next, check the version of CMake: `cmake --version`. If it is below 3.12, you should install a newer version from the website: https://cmake.org/download/.
+
+## C++ Compiler {#c-compiler}
+
+Compilers Clang starting from version 11 is supported for building ClickHouse.
+
+Clang should be used instead of gcc. Though, our continuous integration (CI) platform runs checks for about a dozen of build combinations.
+
+On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
+
+```bash
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
+```
+
+Mac OS X build is also supported. Just run `brew install llvm`
+
+
+## The Building Process {#the-building-process}
+
+Now that you are ready to build ClickHouse we recommend you to create a separate directory `build` inside `ClickHouse` that will contain all of the build artefacts:
+
+    mkdir build
+    cd build
+
+You can have several different directories (build_release, build_debug, etc.) for different types of build.
+
+While inside the `build` directory, configure your build by running CMake. Before the first run, you need to define environment variables that specify compiler.
+
+    export CC=clang CXX=clang++
+    cmake ..
+
+If you installed clang using the automatic installation script above, also specify the version of clang installed in the first command, e.g. `export CC=clang-13 CXX=clang++-13`. The clang version will be in the script output.
+
+The `CC` variable specifies the compiler for C (short for C Compiler), and `CXX` variable instructs which C++ compiler is to be used for building.
+
+For a faster build, you can resort to the `debug` build type - a build with no optimizations. For that supply the following parameter `-D CMAKE_BUILD_TYPE=Debug`:
+
+    cmake -D CMAKE_BUILD_TYPE=Debug ..
+
+You can change the type of build by running this command in the `build` directory.
+
+Run ninja to build:
+
+    ninja clickhouse-server clickhouse-client
+
+Only the required binaries are going to be built in this example.
+
+If you require to build all the binaries (utilities and tests), you should run ninja with no parameters:
+
+    ninja
+
+Full build requires about 30GB of free disk space or 15GB to build the main binaries.
+
+When a large amount of RAM is available on build machine you should limit the number of build tasks run in parallel with `-j` param:
+
+    ninja -j 1 clickhouse-server clickhouse-client
+
+On machines with 4GB of RAM, it is recommended to specify 1, for 8GB of RAM `-j 2` is recommended.
+
+If you get the message: `ninja: error: loading 'build.ninja': No such file or directory`, it means that generating a build configuration has failed and you need to inspect the message above.
+
+Upon the successful start of the building process, you’ll see the build progress - the number of processed tasks and the total number of tasks.
+
+While building messages about protobuf files in libhdfs2 library like `libprotobuf WARNING` may show up. They affect nothing and are safe to be ignored.
+
+Upon successful build you get an executable file `ClickHouse/<build_dir>/programs/clickhouse`:
+
+    ls -l programs/clickhouse
+
+## Running the Built Executable of ClickHouse {#running-the-built-executable-of-clickhouse}
+
+To run the server under the current user you need to navigate to `ClickHouse/programs/server/` (located outside of `build`) and run:
+
+    ../../build/programs/clickhouse server
+
+In this case, ClickHouse will use config files located in the current directory. You can run `clickhouse server` from any directory specifying the path to a config file as a command-line parameter `--config-file`.
+
+To connect to ClickHouse with clickhouse-client in another terminal navigate to `ClickHouse/build/programs/` and run `./clickhouse client`.
+
+If you get `Connection refused` message on Mac OS X or FreeBSD, try specifying host address 127.0.0.1:
+
+    clickhouse client --host 127.0.0.1
+
+You can replace the production version of ClickHouse binary installed in your system with your custom-built ClickHouse binary. To do that install ClickHouse on your machine following the instructions from the official website. Next, run the following:
+
+    sudo service clickhouse-server stop
+    sudo cp ClickHouse/build/programs/clickhouse /usr/bin/
+    sudo service clickhouse-server start
+
+Note that `clickhouse-client`, `clickhouse-server` and others are symlinks to the commonly shared `clickhouse` binary.
+
+You can also run your custom-built ClickHouse binary with the config file from the ClickHouse package installed on your system:
+
+    sudo service clickhouse-server stop
+    sudo -u clickhouse ClickHouse/build/programs/clickhouse server --config-file /etc/clickhouse-server/config.xml
+
+## IDE (Integrated Development Environment) {#ide-integrated-development-environment}
+
+If you do not know which IDE to use, we recommend that you use CLion. CLion is commercial software, but it offers 30 days free trial period. It is also free of charge for students. CLion can be used both on Linux and on Mac OS X.
+
+KDevelop and QTCreator are other great alternatives of an IDE for developing ClickHouse. KDevelop comes in as a very handy IDE although unstable. If KDevelop crashes after a while upon opening project, you should click “Stop All” button as soon as it has opened the list of project’s files. After doing so KDevelop should be fine to work with.
+
+As simple code editors, you can use Sublime Text or Visual Studio Code, or Kate (all of which are available on Linux).
+
+Just in case, it is worth mentioning that CLion creates `build` path on its own, it also on its own selects `debug` for build type, for configuration it uses a version of CMake that is defined in CLion and not the one installed by you, and finally, CLion will use `make` to run build tasks instead of `ninja`. This is normal behaviour, just keep that in mind to avoid confusion.
+
+## Writing Code {#writing-code}
+
+The description of ClickHouse architecture can be found here: https://clickhouse.com/docs/en/development/architecture/
+
+The Code Style Guide: https://clickhouse.com/docs/en/development/style/
+
+Adding third-party libraries: https://clickhouse.com/docs/en/development/contrib/#adding-third-party-libraries
+
+Writing tests: https://clickhouse.com/docs/en/development/tests/
+
+List of tasks: https://github.com/ClickHouse/ClickHouse/issues?q=is%3Aopen+is%3Aissue+label%3Ahacktoberfest
+
+## Test Data {#test-data}
+
+Developing ClickHouse often requires loading realistic datasets. It is particularly important for performance testing. We have a specially prepared set of anonymized data of web analytics. It requires additionally some 3GB of free disk space. Note that this data is not required to accomplish most of the development tasks.
+
+    sudo apt install wget xz-utils
+
+    wget https://datasets.clickhouse.com/hits/tsv/hits_v1.tsv.xz
+    wget https://datasets.clickhouse.com/visits/tsv/visits_v1.tsv.xz
+
+    xz -v -d hits_v1.tsv.xz
+    xz -v -d visits_v1.tsv.xz
+
+    clickhouse-client
+
+    CREATE DATABASE IF NOT EXISTS test
+
+    CREATE TABLE test.hits ( WatchID UInt64,  JavaEnable UInt8,  Title String,  GoodEvent Int16,  EventTime DateTime,  EventDate Date,  CounterID UInt32,  ClientIP UInt32,  ClientIP6 FixedString(16),  RegionID UInt32,  UserID UInt64,  CounterClass Int8,  OS UInt8,  UserAgent UInt8,  URL String,  Referer String,  URLDomain String,  RefererDomain String,  Refresh UInt8,  IsRobot UInt8,  RefererCategories Array(UInt16),  URLCategories Array(UInt16),  URLRegions Array(UInt32),  RefererRegions Array(UInt32),  ResolutionWidth UInt16,  ResolutionHeight UInt16,  ResolutionDepth UInt8,  FlashMajor UInt8,  FlashMinor UInt8,  FlashMinor2 String,  NetMajor UInt8,  NetMinor UInt8,  UserAgentMajor UInt16,  UserAgentMinor FixedString(2),  CookieEnable UInt8,  JavascriptEnable UInt8,  IsMobile UInt8,  MobilePhone UInt8,  MobilePhoneModel String,  Params String,  IPNetworkID UInt32,  TraficSourceID Int8,  SearchEngineID UInt16,  SearchPhrase String,  AdvEngineID UInt8,  IsArtifical UInt8,  WindowClientWidth UInt16,  WindowClientHeight UInt16,  ClientTimeZone Int16,  ClientEventTime DateTime,  SilverlightVersion1 UInt8,  SilverlightVersion2 UInt8,  SilverlightVersion3 UInt32,  SilverlightVersion4 UInt16,  PageCharset String,  CodeVersion UInt32,  IsLink UInt8,  IsDownload UInt8,  IsNotBounce UInt8,  FUniqID UInt64,  HID UInt32,  IsOldCounter UInt8,  IsEvent UInt8,  IsParameter UInt8,  DontCountHits UInt8,  WithHash UInt8,  HitColor FixedString(1),  UTCEventTime DateTime,  Age UInt8,  Sex UInt8,  Income UInt8,  Interests UInt16,  Robotness UInt8,  GeneralInterests Array(UInt16),  RemoteIP UInt32,  RemoteIP6 FixedString(16),  WindowName Int32,  OpenerName Int32,  HistoryLength Int16,  BrowserLanguage FixedString(2),  BrowserCountry FixedString(2),  SocialNetwork String,  SocialAction String,  HTTPError UInt16,  SendTiming Int32,  DNSTiming Int32,  ConnectTiming Int32,  ResponseStartTiming Int32,  ResponseEndTiming Int32,  FetchTiming Int32,  RedirectTiming Int32,  DOMInteractiveTiming Int32,  DOMContentLoadedTiming Int32,  DOMCompleteTiming Int32,  LoadEventStartTiming Int32,  LoadEventEndTiming Int32,  NSToDOMContentLoadedTiming Int32,  FirstPaintTiming Int32,  RedirectCount Int8,  SocialSourceNetworkID UInt8,  SocialSourcePage String,  ParamPrice Int64,  ParamOrderID String,  ParamCurrency FixedString(3),  ParamCurrencyID UInt16,  GoalsReached Array(UInt32),  OpenstatServiceName String,  OpenstatCampaignID String,  OpenstatAdID String,  OpenstatSourceID String,  UTMSource String,  UTMMedium String,  UTMCampaign String,  UTMContent String,  UTMTerm String,  FromTag String,  HasGCLID UInt8,  RefererHash UInt64,  URLHash UInt64,  CLID UInt32,  YCLID UInt64,  ShareService String,  ShareURL String,  ShareTitle String,  `ParsedParams.Key1` Array(String),  `ParsedParams.Key2` Array(String),  `ParsedParams.Key3` Array(String),  `ParsedParams.Key4` Array(String),  `ParsedParams.Key5` Array(String),  `ParsedParams.ValueDouble` Array(Float64),  IslandID FixedString(16),  RequestNum UInt32,  RequestTry UInt8) ENGINE = MergeTree PARTITION BY toYYYYMM(EventDate) SAMPLE BY intHash32(UserID) ORDER BY (CounterID, EventDate, intHash32(UserID), EventTime);
+
+    CREATE TABLE test.visits ( CounterID UInt32,  StartDate Date,  Sign Int8,  IsNew UInt8,  VisitID UInt64,  UserID UInt64,  StartTime DateTime,  Duration UInt32,  UTCStartTime DateTime,  PageViews Int32,  Hits Int32,  IsBounce UInt8,  Referer String,  StartURL String,  RefererDomain String,  StartURLDomain String,  EndURL String,  LinkURL String,  IsDownload UInt8,  TraficSourceID Int8,  SearchEngineID UInt16,  SearchPhrase String,  AdvEngineID UInt8,  PlaceID Int32,  RefererCategories Array(UInt16),  URLCategories Array(UInt16),  URLRegions Array(UInt32),  RefererRegions Array(UInt32),  IsYandex UInt8,  GoalReachesDepth Int32,  GoalReachesURL Int32,  GoalReachesAny Int32,  SocialSourceNetworkID UInt8,  SocialSourcePage String,  MobilePhoneModel String,  ClientEventTime DateTime,  RegionID UInt32,  ClientIP UInt32,  ClientIP6 FixedString(16),  RemoteIP UInt32,  RemoteIP6 FixedString(16),  IPNetworkID UInt32,  SilverlightVersion3 UInt32,  CodeVersion UInt32,  ResolutionWidth UInt16,  ResolutionHeight UInt16,  UserAgentMajor UInt16,  UserAgentMinor UInt16,  WindowClientWidth UInt16,  WindowClientHeight UInt16,  SilverlightVersion2 UInt8,  SilverlightVersion4 UInt16,  FlashVersion3 UInt16,  FlashVersion4 UInt16,  ClientTimeZone Int16,  OS UInt8,  UserAgent UInt8,  ResolutionDepth UInt8,  FlashMajor UInt8,  FlashMinor UInt8,  NetMajor UInt8,  NetMinor UInt8,  MobilePhone UInt8,  SilverlightVersion1 UInt8,  Age UInt8,  Sex UInt8,  Income UInt8,  JavaEnable UInt8,  CookieEnable UInt8,  JavascriptEnable UInt8,  IsMobile UInt8,  BrowserLanguage UInt16,  BrowserCountry UInt16,  Interests UInt16,  Robotness UInt8,  GeneralInterests Array(UInt16),  Params Array(String),  `Goals.ID` Array(UInt32),  `Goals.Serial` Array(UInt32),  `Goals.EventTime` Array(DateTime),  `Goals.Price` Array(Int64),  `Goals.OrderID` Array(String),  `Goals.CurrencyID` Array(UInt32),  WatchIDs Array(UInt64),  ParamSumPrice Int64,  ParamCurrency FixedString(3),  ParamCurrencyID UInt16,  ClickLogID UInt64,  ClickEventID Int32,  ClickGoodEvent Int32,  ClickEventTime DateTime,  ClickPriorityID Int32,  ClickPhraseID Int32,  ClickPageID Int32,  ClickPlaceID Int32,  ClickTypeID Int32,  ClickResourceID Int32,  ClickCost UInt32,  ClickClientIP UInt32,  ClickDomainID UInt32,  ClickURL String,  ClickAttempt UInt8,  ClickOrderID UInt32,  ClickBannerID UInt32,  ClickMarketCategoryID UInt32,  ClickMarketPP UInt32,  ClickMarketCategoryName String,  ClickMarketPPName String,  ClickAWAPSCampaignName String,  ClickPageName String,  ClickTargetType UInt16,  ClickTargetPhraseID UInt64,  ClickContextType UInt8,  ClickSelectType Int8,  ClickOptions String,  ClickGroupBannerID Int32,  OpenstatServiceName String,  OpenstatCampaignID String,  OpenstatAdID String,  OpenstatSourceID String,  UTMSource String,  UTMMedium String,  UTMCampaign String,  UTMContent String,  UTMTerm String,  FromTag String,  HasGCLID UInt8,  FirstVisit DateTime,  PredLastVisit Date,  LastVisit Date,  TotalVisits UInt32,  `TraficSource.ID` Array(Int8),  `TraficSource.SearchEngineID` Array(UInt16),  `TraficSource.AdvEngineID` Array(UInt8),  `TraficSource.PlaceID` Array(UInt16),  `TraficSource.SocialSourceNetworkID` Array(UInt8),  `TraficSource.Domain` Array(String),  `TraficSource.SearchPhrase` Array(String),  `TraficSource.SocialSourcePage` Array(String),  Attendance FixedString(16),  CLID UInt32,  YCLID UInt64,  NormalizedRefererHash UInt64,  SearchPhraseHash UInt64,  RefererDomainHash UInt64,  NormalizedStartURLHash UInt64,  StartURLDomainHash UInt64,  NormalizedEndURLHash UInt64,  TopLevelDomain UInt64,  URLScheme UInt64,  OpenstatServiceNameHash UInt64,  OpenstatCampaignIDHash UInt64,  OpenstatAdIDHash UInt64,  OpenstatSourceIDHash UInt64,  UTMSourceHash UInt64,  UTMMediumHash UInt64,  UTMCampaignHash UInt64,  UTMContentHash UInt64,  UTMTermHash UInt64,  FromHash UInt64,  WebVisorEnabled UInt8,  WebVisorActivity UInt32,  `ParsedParams.Key1` Array(String),  `ParsedParams.Key2` Array(String),  `ParsedParams.Key3` Array(String),  `ParsedParams.Key4` Array(String),  `ParsedParams.Key5` Array(String),  `ParsedParams.ValueDouble` Array(Float64),  `Market.Type` Array(UInt8),  `Market.GoalID` Array(UInt32),  `Market.OrderID` Array(String),  `Market.OrderPrice` Array(Int64),  `Market.PP` Array(UInt32),  `Market.DirectPlaceID` Array(UInt32),  `Market.DirectOrderID` Array(UInt32),  `Market.DirectBannerID` Array(UInt32),  `Market.GoodID` Array(String),  `Market.GoodName` Array(String),  `Market.GoodQuantity` Array(Int32),  `Market.GoodPrice` Array(Int64),  IslandID FixedString(16)) ENGINE = CollapsingMergeTree(Sign) PARTITION BY toYYYYMM(StartDate) SAMPLE BY intHash32(UserID) ORDER BY (CounterID, StartDate, intHash32(UserID), VisitID);
+
+    clickhouse-client --max_insert_block_size 100000 --query "INSERT INTO test.hits FORMAT TSV" < hits_v1.tsv
+    clickhouse-client --max_insert_block_size 100000 --query "INSERT INTO test.visits FORMAT TSV" < visits_v1.tsv
+
+## Creating Pull Request {#creating-pull-request}
+
+Navigate to your fork repository in GitHub’s UI. If you have been developing in a branch, you need to select that branch. There will be a “Pull request” button located on the screen. In essence, this means “create a request for accepting my changes into the main repository”.
+
+A pull request can be created even if the work is not completed yet. In this case please put the word “WIP” (work in progress) at the beginning of the title, it can be changed later. This is useful for cooperative reviewing and discussion of changes as well as for running all of the available tests. It is important that you provide a brief description of your changes, it will later be used for generating release changelogs.
+
+Testing will commence as soon as ClickHouse employees label your PR with a tag “can be tested”. The results of some first checks (e.g. code style) will come in within several minutes. Build check results will arrive within half an hour. And the main set of tests will report itself within an hour.
+
+The system will prepare ClickHouse binary builds for your pull request individually. To retrieve these builds click the “Details” link next to “ClickHouse build check” entry in the list of checks. There you will find direct links to the built .deb packages of ClickHouse which you can deploy even on your production servers (if you have no fear).
+
+Most probably some of the builds will fail at first times. This is due to the fact that we check builds both with gcc as well as with clang, with almost all of existing warnings (always with the `-Werror` flag) enabled for clang. On that same page, you can find all of the build logs so that you do not have to build ClickHouse in all of the possible ways.
diff --git a/docs/en/reference/development/style.md b/docs/en/reference/development/style.md
new file mode 100644
index 00000000000..82cd9273680
--- /dev/null
+++ b/docs/en/reference/development/style.md
@@ -0,0 +1,832 @@
+---
+sidebar_position: 69
+sidebar_label: C++ Guide
+description: A list of recommendations regarding coding style, naming convention, formatting and more
+---
+
+# How to Write C++ Code 
+
+## General Recommendations {#general-recommendations}
+
+**1.** The following are recommendations, not requirements.
+
+**2.** If you are editing code, it makes sense to follow the formatting of the existing code.
+
+**3.** Code style is needed for consistency. Consistency makes it easier to read the code, and it also makes it easier to search the code.
+
+**4.** Many of the rules do not have logical reasons; they are dictated by established practices.
+
+## Formatting {#formatting}
+
+**1.** Most of the formatting will be done automatically by `clang-format`.
+
+**2.** Indents are 4 spaces. Configure your development environment so that a tab adds four spaces.
+
+**3.** Opening and closing curly brackets must be on a separate line.
+
+``` cpp
+inline void readBoolText(bool & x, ReadBuffer & buf)
+{
+    char tmp = '0';
+    readChar(tmp, buf);
+    x = tmp != '0';
+}
+```
+
+**4.** If the entire function body is a single `statement`, it can be placed on a single line. Place spaces around curly braces (besides the space at the end of the line).
+
+``` cpp
+inline size_t mask() const                { return buf_size() - 1; }
+inline size_t place(HashValue x) const    { return x & mask(); }
+```
+
+**5.** For functions. Don’t put spaces around brackets.
+
+``` cpp
+void reinsert(const Value & x)
+```
+
+``` cpp
+memcpy(&buf[place_value], &x, sizeof(x));
+```
+
+**6.** In `if`, `for`, `while` and other expressions, a space is inserted in front of the opening bracket (as opposed to function calls).
+
+``` cpp
+for (size_t i = 0; i < rows; i += storage.index_granularity)
+```
+
+**7.** Add spaces around binary operators (`+`, `-`, `*`, `/`, `%`, …) and the ternary operator `?:`.
+
+``` cpp
+UInt16 year = (s[0] - '0') * 1000 + (s[1] - '0') * 100 + (s[2] - '0') * 10 + (s[3] - '0');
+UInt8 month = (s[5] - '0') * 10 + (s[6] - '0');
+UInt8 day = (s[8] - '0') * 10 + (s[9] - '0');
+```
+
+**8.** If a line feed is entered, put the operator on a new line and increase the indent before it.
+
+``` cpp
+if (elapsed_ns)
+    message << " ("
+        << rows_read_on_server * 1000000000 / elapsed_ns << " rows/s., "
+        << bytes_read_on_server * 1000.0 / elapsed_ns << " MB/s.) ";
+```
+
+**9.** You can use spaces for alignment within a line, if desired.
+
+``` cpp
+dst.ClickLogID         = click.LogID;
+dst.ClickEventID       = click.EventID;
+dst.ClickGoodEvent     = click.GoodEvent;
+```
+
+**10.** Don’t use spaces around the operators `.`, `->`.
+
+If necessary, the operator can be wrapped to the next line. In this case, the offset in front of it is increased.
+
+**11.** Do not use a space to separate unary operators (`--`, `++`, `*`, `&`, …) from the argument.
+
+**12.** Put a space after a comma, but not before it. The same rule goes for a semicolon inside a `for` expression.
+
+**13.** Do not use spaces to separate the `[]` operator.
+
+**14.** In a `template <...>` expression, use a space between `template` and `<`; no spaces after `<` or before `>`.
+
+``` cpp
+template <typename TKey, typename TValue>
+struct AggregatedStatElement
+{}
+```
+
+**15.** In classes and structures, write `public`, `private`, and `protected` on the same level as `class/struct`, and indent the rest of the code.
+
+``` cpp
+template <typename T>
+class MultiVersion
+{
+public:
+    /// Version of object for usage. shared_ptr manage lifetime of version.
+    using Version = std::shared_ptr<const T>;
+    ...
+}
+```
+
+**16.** If the same `namespace` is used for the entire file, and there isn’t anything else significant, an offset is not necessary inside `namespace`.
+
+**17.** If the block for an `if`, `for`, `while`, or other expression consists of a single `statement`, the curly brackets are optional. Place the `statement` on a separate line, instead. This rule is also valid for nested `if`, `for`, `while`, …
+
+But if the inner `statement` contains curly brackets or `else`, the external block should be written in curly brackets.
+
+``` cpp
+/// Finish write.
+for (auto & stream : streams)
+    stream.second->finalize();
+```
+
+**18.** There shouldn’t be any spaces at the ends of lines.
+
+**19.** Source files are UTF-8 encoded.
+
+**20.** Non-ASCII characters can be used in string literals.
+
+``` cpp
+<< ", " << (timer.elapsed() / chunks_stats.hits) << " μsec/hit.";
+```
+
+**21.** Do not write multiple expressions in a single line.
+
+**22.** Group sections of code inside functions and separate them with no more than one empty line.
+
+**23.** Separate functions, classes, and so on with one or two empty lines.
+
+**24.** `A const` (related to a value) must be written before the type name.
+
+``` cpp
+//correct
+const char * pos
+const std::string & s
+//incorrect
+char const * pos
+```
+
+**25.** When declaring a pointer or reference, the `*` and `&` symbols should be separated by spaces on both sides.
+
+``` cpp
+//correct
+const char * pos
+//incorrect
+const char* pos
+const char *pos
+```
+
+**26.** When using template types, alias them with the `using` keyword (except in the simplest cases).
+
+In other words, the template parameters are specified only in `using` and aren’t repeated in the code.
+
+`using` can be declared locally, such as inside a function.
+
+``` cpp
+//correct
+using FileStreams = std::map<std::string, std::shared_ptr<Stream>>;
+FileStreams streams;
+//incorrect
+std::map<std::string, std::shared_ptr<Stream>> streams;
+```
+
+**27.** Do not declare several variables of different types in one statement.
+
+``` cpp
+//incorrect
+int x, *y;
+```
+
+**28.** Do not use C-style casts.
+
+``` cpp
+//incorrect
+std::cerr << (int)c <<; std::endl;
+//correct
+std::cerr << static_cast<int>(c) << std::endl;
+```
+
+**29.** In classes and structs, group members and functions separately inside each visibility scope.
+
+**30.** For small classes and structs, it is not necessary to separate the method declaration from the implementation.
+
+The same is true for small methods in any classes or structs.
+
+For templated classes and structs, do not separate the method declarations from the implementation (because otherwise they must be defined in the same translation unit).
+
+**31.** You can wrap lines at 140 characters, instead of 80.
+
+**32.** Always use the prefix increment/decrement operators if postfix is not required.
+
+``` cpp
+for (Names::const_iterator it = column_names.begin(); it != column_names.end(); ++it)
+```
+
+## Comments {#comments}
+
+**1.** Be sure to add comments for all non-trivial parts of code.
+
+This is very important. Writing the comment might help you realize that the code isn’t necessary, or that it is designed wrong.
+
+``` cpp
+/** Part of piece of memory, that can be used.
+  * For example, if internal_buffer is 1MB, and there was only 10 bytes loaded to buffer from file for reading,
+  * then working_buffer will have size of only 10 bytes
+  * (working_buffer.end() will point to position right after those 10 bytes available for read).
+  */
+```
+
+**2.** Comments can be as detailed as necessary.
+
+**3.** Place comments before the code they describe. In rare cases, comments can come after the code, on the same line.
+
+``` cpp
+/** Parses and executes the query.
+*/
+void executeQuery(
+    ReadBuffer & istr, /// Where to read the query from (and data for INSERT, if applicable)
+    WriteBuffer & ostr, /// Where to write the result
+    Context & context, /// DB, tables, data types, engines, functions, aggregate functions...
+    BlockInputStreamPtr & query_plan, /// Here could be written the description on how query was executed
+    QueryProcessingStage::Enum stage = QueryProcessingStage::Complete /// Up to which stage process the SELECT query
+    )
+```
+
+**4.** Comments should be written in English only.
+
+**5.** If you are writing a library, include detailed comments explaining it in the main header file.
+
+**6.** Do not add comments that do not provide additional information. In particular, do not leave empty comments like this:
+
+``` cpp
+/*
+* Procedure Name:
+* Original procedure name:
+* Author:
+* Date of creation:
+* Dates of modification:
+* Modification authors:
+* Original file name:
+* Purpose:
+* Intent:
+* Designation:
+* Classes used:
+* Constants:
+* Local variables:
+* Parameters:
+* Date of creation:
+* Purpose:
+*/
+```
+
+The example is borrowed from the resource http://home.tamk.fi/~jaalto/course/coding-style/doc/unmaintainable-code/.
+
+**7.** Do not write garbage comments (author, creation date ..) at the beginning of each file.
+
+**8.** Single-line comments begin with three slashes: `///` and multi-line comments begin with `/**`. These comments are considered “documentation”.
+
+Note: You can use Doxygen to generate documentation from these comments. But Doxygen is not generally used because it is more convenient to navigate the code in the IDE.
+
+**9.** Multi-line comments must not have empty lines at the beginning and end (except the line that closes a multi-line comment).
+
+**10.** For commenting out code, use basic comments, not “documenting” comments.
+
+**11.** Delete the commented out parts of the code before committing.
+
+**12.** Do not use profanity in comments or code.
+
+**13.** Do not use uppercase letters. Do not use excessive punctuation.
+
+``` cpp
+/// WHAT THE FAIL???
+```
+
+**14.** Do not use comments to make delimeters.
+
+``` cpp
+///******************************************************
+```
+
+**15.** Do not start discussions in comments.
+
+``` cpp
+/// Why did you do this stuff?
+```
+
+**16.** There’s no need to write a comment at the end of a block describing what it was about.
+
+``` cpp
+/// for
+```
+
+## Names {#names}
+
+**1.** Use lowercase letters with underscores in the names of variables and class members.
+
+``` cpp
+size_t max_block_size;
+```
+
+**2.** For the names of functions (methods), use camelCase beginning with a lowercase letter.
+
+``` cpp
+std::string getName() const override { return "Memory"; }
+```
+
+**3.** For the names of classes (structs), use CamelCase beginning with an uppercase letter. Prefixes other than I are not used for interfaces.
+
+``` cpp
+class StorageMemory : public IStorage
+```
+
+**4.** `using` are named the same way as classes.
+
+**5.** Names of template type arguments: in simple cases, use `T`; `T`, `U`; `T1`, `T2`.
+
+For more complex cases, either follow the rules for class names, or add the prefix `T`.
+
+``` cpp
+template <typename TKey, typename TValue>
+struct AggregatedStatElement
+```
+
+**6.** Names of template constant arguments: either follow the rules for variable names, or use `N` in simple cases.
+
+``` cpp
+template <bool without_www>
+struct ExtractDomain
+```
+
+**7.** For abstract classes (interfaces) you can add the `I` prefix.
+
+``` cpp
+class IBlockInputStream
+```
+
+**8.** If you use a variable locally, you can use the short name.
+
+In all other cases, use a name that describes the meaning.
+
+``` cpp
+bool info_successfully_loaded = false;
+```
+
+**9.** Names of `define`s and global constants use ALL_CAPS with underscores.
+
+``` cpp
+#define MAX_SRC_TABLE_NAMES_TO_STORE 1000
+```
+
+**10.** File names should use the same style as their contents.
+
+If a file contains a single class, name the file the same way as the class (CamelCase).
+
+If the file contains a single function, name the file the same way as the function (camelCase).
+
+**11.** If the name contains an abbreviation, then:
+
+-   For variable names, the abbreviation should use lowercase letters `mysql_connection` (not `mySQL_connection`).
+-   For names of classes and functions, keep the uppercase letters in the abbreviation`MySQLConnection` (not `MySqlConnection`).
+
+**12.** Constructor arguments that are used just to initialize the class members should be named the same way as the class members, but with an underscore at the end.
+
+``` cpp
+FileQueueProcessor(
+    const std::string & path_,
+    const std::string & prefix_,
+    std::shared_ptr<FileHandler> handler_)
+    : path(path_),
+    prefix(prefix_),
+    handler(handler_),
+    log(&Logger::get("FileQueueProcessor"))
+{
+}
+```
+
+The underscore suffix can be omitted if the argument is not used in the constructor body.
+
+**13.** There is no difference in the names of local variables and class members (no prefixes required).
+
+``` cpp
+timer (not m_timer)
+```
+
+**14.** For the constants in an `enum`, use CamelCase with a capital letter. ALL_CAPS is also acceptable. If the `enum` is non-local, use an `enum class`.
+
+``` cpp
+enum class CompressionMethod
+{
+    QuickLZ = 0,
+    LZ4     = 1,
+};
+```
+
+**15.** All names must be in English. Transliteration of Hebrew words is not allowed.
+
+    not T_PAAMAYIM_NEKUDOTAYIM
+
+**16.** Abbreviations are acceptable if they are well known (when you can easily find the meaning of the abbreviation in Wikipedia or in a search engine).
+
+    `AST`, `SQL`.
+
+    Not `NVDH` (some random letters)
+
+Incomplete words are acceptable if the shortened version is common use.
+
+You can also use an abbreviation if the full name is included next to it in the comments.
+
+**17.** File names with C++ source code must have the `.cpp` extension. Header files must have the `.h` extension.
+
+## How to Write Code {#how-to-write-code}
+
+**1.** Memory management.
+
+Manual memory deallocation (`delete`) can only be used in library code.
+
+In library code, the `delete` operator can only be used in destructors.
+
+In application code, memory must be freed by the object that owns it.
+
+Examples:
+
+-   The easiest way is to place an object on the stack, or make it a member of another class.
+-   For a large number of small objects, use containers.
+-   For automatic deallocation of a small number of objects that reside in the heap, use `shared_ptr/unique_ptr`.
+
+**2.** Resource management.
+
+Use `RAII` and see above.
+
+**3.** Error handling.
+
+Use exceptions. In most cases, you only need to throw an exception, and do not need to catch it (because of `RAII`).
+
+In offline data processing applications, it’s often acceptable to not catch exceptions.
+
+In servers that handle user requests, it’s usually enough to catch exceptions at the top level of the connection handler.
+
+In thread functions, you should catch and keep all exceptions to rethrow them in the main thread after `join`.
+
+``` cpp
+/// If there weren't any calculations yet, calculate the first block synchronously
+if (!started)
+{
+    calculate();
+    started = true;
+}
+else /// If calculations are already in progress, wait for the result
+    pool.wait();
+
+if (exception)
+    exception->rethrow();
+```
+
+Never hide exceptions without handling. Never just blindly put all exceptions to log.
+
+``` cpp
+//Not correct
+catch (...) {}
+```
+
+If you need to ignore some exceptions, do so only for specific ones and rethrow the rest.
+
+``` cpp
+catch (const DB::Exception & e)
+{
+    if (e.code() == ErrorCodes::UNKNOWN_AGGREGATE_FUNCTION)
+        return nullptr;
+    else
+        throw;
+}
+```
+
+When using functions with response codes or `errno`, always check the result and throw an exception in case of error.
+
+``` cpp
+if (0 != close(fd))
+    throwFromErrno("Cannot close file " + file_name, ErrorCodes::CANNOT_CLOSE_FILE);
+```
+
+You can use assert to check invariants in code.
+
+**4.** Exception types.
+
+There is no need to use complex exception hierarchy in application code. The exception text should be understandable to a system administrator.
+
+**5.** Throwing exceptions from destructors.
+
+This is not recommended, but it is allowed.
+
+Use the following options:
+
+-   Create a function (`done()` or `finalize()`) that will do all the work in advance that might lead to an exception. If that function was called, there should be no exceptions in the destructor later.
+-   Tasks that are too complex (such as sending messages over the network) can be put in separate method that the class user will have to call before destruction.
+-   If there is an exception in the destructor, it’s better to log it than to hide it (if the logger is available).
+-   In simple applications, it is acceptable to rely on `std::terminate` (for cases of `noexcept` by default in C++11) to handle exceptions.
+
+**6.** Anonymous code blocks.
+
+You can create a separate code block inside a single function in order to make certain variables local, so that the destructors are called when exiting the block.
+
+``` cpp
+Block block = data.in->read();
+
+{
+    std::lock_guard<std::mutex> lock(mutex);
+    data.ready = true;
+    data.block = block;
+}
+
+ready_any.set();
+```
+
+**7.** Multithreading.
+
+In offline data processing programs:
+
+-   Try to get the best possible performance on a single CPU core. You can then parallelize your code if necessary.
+
+In server applications:
+
+-   Use the thread pool to process requests. At this point, we haven’t had any tasks that required userspace context switching.
+
+Fork is not used for parallelization.
+
+**8.** Syncing threads.
+
+Often it is possible to make different threads use different memory cells (even better: different cache lines,) and to not use any thread synchronization (except `joinAll`).
+
+If synchronization is required, in most cases, it is sufficient to use mutex under `lock_guard`.
+
+In other cases use system synchronization primitives. Do not use busy wait.
+
+Atomic operations should be used only in the simplest cases.
+
+Do not try to implement lock-free data structures unless it is your primary area of expertise.
+
+**9.** Pointers vs references.
+
+In most cases, prefer references.
+
+**10.** const.
+
+Use constant references, pointers to constants, `const_iterator`, and const methods.
+
+Consider `const` to be default and use non-`const` only when necessary.
+
+When passing variables by value, using `const` usually does not make sense.
+
+**11.** unsigned.
+
+Use `unsigned` if necessary.
+
+**12.** Numeric types.
+
+Use the types `UInt8`, `UInt16`, `UInt32`, `UInt64`, `Int8`, `Int16`, `Int32`, and `Int64`, as well as `size_t`, `ssize_t`, and `ptrdiff_t`.
+
+Don’t use these types for numbers: `signed/unsigned long`, `long long`, `short`, `signed/unsigned char`, `char`.
+
+**13.** Passing arguments.
+
+Pass complex values by value if they are going to be moved and use std::move; pass by reference if you want to update value in a loop.
+
+If a function captures ownership of an object created in the heap, make the argument type `shared_ptr` or `unique_ptr`.
+
+**14.** Return values.
+
+In most cases, just use `return`. Do not write `return std::move(res)`.
+
+If the function allocates an object on heap and returns it, use `shared_ptr` or `unique_ptr`.
+
+In rare cases (updating a value in a loop) you might need to return the value via an argument. In this case, the argument should be a reference.
+
+``` cpp
+using AggregateFunctionPtr = std::shared_ptr<IAggregateFunction>;
+
+/** Allows creating an aggregate function by its name.
+  */
+class AggregateFunctionFactory
+{
+public:
+    AggregateFunctionFactory();
+    AggregateFunctionPtr get(const String & name, const DataTypes & argument_types) const;
+```
+
+**15.** namespace.
+
+There is no need to use a separate `namespace` for application code.
+
+Small libraries do not need this, either.
+
+For medium to large libraries, put everything in a `namespace`.
+
+In the library’s `.h` file, you can use `namespace detail` to hide implementation details not needed for the application code.
+
+In a `.cpp` file, you can use a `static` or anonymous namespace to hide symbols.
+
+Also, a `namespace` can be used for an `enum` to prevent the corresponding names from falling into an external `namespace` (but it’s better to use an `enum class`).
+
+**16.** Deferred initialization.
+
+If arguments are required for initialization, then you normally shouldn’t write a default constructor.
+
+If later you’ll need to delay initialization, you can add a default constructor that will create an invalid object. Or, for a small number of objects, you can use `shared_ptr/unique_ptr`.
+
+``` cpp
+Loader(DB::Connection * connection_, const std::string & query, size_t max_block_size_);
+
+/// For deferred initialization
+Loader() {}
+```
+
+**17.** Virtual functions.
+
+If the class is not intended for polymorphic use, you do not need to make functions virtual. This also applies to the destructor.
+
+**18.** Encodings.
+
+Use UTF-8 everywhere. Use `std::string` and `char *`. Do not use `std::wstring` and `wchar_t`.
+
+**19.** Logging.
+
+See the examples everywhere in the code.
+
+Before committing, delete all meaningless and debug logging, and any other types of debug output.
+
+Logging in cycles should be avoided, even on the Trace level.
+
+Logs must be readable at any logging level.
+
+Logging should only be used in application code, for the most part.
+
+Log messages must be written in English.
+
+The log should preferably be understandable for the system administrator.
+
+Do not use profanity in the log.
+
+Use UTF-8 encoding in the log. In rare cases you can use non-ASCII characters in the log.
+
+**20.** Input-output.
+
+Don’t use `iostreams` in internal cycles that are critical for application performance (and never use `stringstream`).
+
+Use the `DB/IO` library instead.
+
+**21.** Date and time.
+
+See the `DateLUT` library.
+
+**22.** include.
+
+Always use `#pragma once` instead of include guards.
+
+**23.** using.
+
+`using namespace` is not used. You can use `using` with something specific. But make it local inside a class or function.
+
+**24.** Do not use `trailing return type` for functions unless necessary.
+
+``` cpp
+auto f() -> void
+```
+
+**25.** Declaration and initialization of variables.
+
+``` cpp
+//right way
+std::string s = "Hello";
+std::string s{"Hello"};
+
+//wrong way
+auto s = std::string{"Hello"};
+```
+
+**26.** For virtual functions, write `virtual` in the base class, but write `override` instead of `virtual` in descendent classes.
+
+## Unused Features of C++ {#unused-features-of-c}
+
+**1.** Virtual inheritance is not used.
+
+**2.** Exception specifiers from C++03 are not used.
+
+## Platform {#platform}
+
+**1.** We write code for a specific platform.
+
+But other things being equal, cross-platform or portable code is preferred.
+
+**2.** Language: C++20 (see the list of available [C++20 features](https://en.cppreference.com/w/cpp/compiler_support#C.2B.2B20_features)).
+
+**3.** Compiler: `clang`. At this time (April 2021), the code is compiled using clang version 11. (It can also be compiled using `gcc` version 10, but it's untested and not suitable for production usage).
+
+The standard library is used (`libc++`).
+
+**4.**OS: Linux Ubuntu, not older than Precise.
+
+**5.**Code is written for x86_64 CPU architecture.
+
+The CPU instruction set is the minimum supported set among our servers. Currently, it is SSE 4.2.
+
+**6.** Use `-Wall -Wextra -Werror` compilation flags. Also `-Weverything` is used with few exceptions.
+
+**7.** Use static linking with all libraries except those that are difficult to connect to statically (see the output of the `ldd` command).
+
+**8.** Code is developed and debugged with release settings.
+
+## Tools {#tools}
+
+**1.** KDevelop is a good IDE.
+
+**2.** For debugging, use `gdb`, `valgrind` (`memcheck`), `strace`, `-fsanitize=...`, or `tcmalloc_minimal_debug`.
+
+**3.** For profiling, use `Linux Perf`, `valgrind` (`callgrind`), or `strace -cf`.
+
+**4.** Sources are in Git.
+
+**5.** Assembly uses `CMake`.
+
+**6.** Programs are released using `deb` packages.
+
+**7.** Commits to master must not break the build.
+
+Though only selected revisions are considered workable.
+
+**8.** Make commits as often as possible, even if the code is only partially ready.
+
+Use branches for this purpose.
+
+If your code in the `master` branch is not buildable yet, exclude it from the build before the `push`. You’ll need to finish it or remove it within a few days.
+
+**9.** For non-trivial changes, use branches and publish them on the server.
+
+**10.** Unused code is removed from the repository.
+
+## Libraries {#libraries}
+
+**1.** The C++20 standard library is used (experimental extensions are allowed), as well as `boost` and `Poco` frameworks.
+
+**2.** It is not allowed to use libraries from OS packages. It is also not allowed to use pre-installed libraries. All libraries should be placed in form of source code in `contrib` directory and built with ClickHouse. See [Guidelines for adding new third-party libraries](contrib.md#adding-third-party-libraries) for details.
+
+**3.** Preference is always given to libraries that are already in use.
+
+## General Recommendations {#general-recommendations-1}
+
+**1.** Write as little code as possible.
+
+**2.** Try the simplest solution.
+
+**3.** Don’t write code until you know how it’s going to work and how the inner loop will function.
+
+**4.** In the simplest cases, use `using` instead of classes or structs.
+
+**5.** If possible, do not write copy constructors, assignment operators, destructors (other than a virtual one, if the class contains at least one virtual function), move constructors or move assignment operators. In other words, the compiler-generated functions must work correctly. You can use `default`.
+
+**6.** Code simplification is encouraged. Reduce the size of your code where possible.
+
+## Additional Recommendations {#additional-recommendations}
+
+**1.** Explicitly specifying `std::` for types from `stddef.h`
+
+is not recommended. In other words, we recommend writing `size_t` instead `std::size_t`, because it’s shorter.
+
+It is acceptable to add `std::`.
+
+**2.** Explicitly specifying `std::` for functions from the standard C library
+
+is not recommended. In other words, write `memcpy` instead of `std::memcpy`.
+
+The reason is that there are similar non-standard functions, such as `memmem`. We do use these functions on occasion. These functions do not exist in `namespace std`.
+
+If you write `std::memcpy` instead of `memcpy` everywhere, then `memmem` without `std::` will look strange.
+
+Nevertheless, you can still use `std::` if you prefer it.
+
+**3.** Using functions from C when the same ones are available in the standard C++ library.
+
+This is acceptable if it is more efficient.
+
+For example, use `memcpy` instead of `std::copy` for copying large chunks of memory.
+
+**4.** Multiline function arguments.
+
+Any of the following wrapping styles are allowed:
+
+``` cpp
+function(
+  T1 x1,
+  T2 x2)
+```
+
+``` cpp
+function(
+  size_t left, size_t right,
+  const & RangesInDataParts ranges,
+  size_t limit)
+```
+
+``` cpp
+function(size_t left, size_t right,
+  const & RangesInDataParts ranges,
+  size_t limit)
+```
+
+``` cpp
+function(size_t left, size_t right,
+      const & RangesInDataParts ranges,
+      size_t limit)
+```
+
+``` cpp
+function(
+      size_t left,
+      size_t right,
+      const & RangesInDataParts ranges,
+      size_t limit)
+```
+
+[Original article](https://clickhouse.com/docs/en/development/style/) <!--hide-->
diff --git a/docs/en/reference/development/tests.md b/docs/en/reference/development/tests.md
new file mode 100644
index 00000000000..29b69f0b697
--- /dev/null
+++ b/docs/en/reference/development/tests.md
@@ -0,0 +1,297 @@
+---
+sidebar_position: 70
+sidebar_label: Testing
+description: Most of ClickHouse features can be tested with functional tests and they are mandatory to use for every change in ClickHouse code that can be tested that way.
+---
+
+# ClickHouse Testing 
+
+## Functional Tests
+
+Functional tests are the most simple and convenient to use. Most of ClickHouse features can be tested with functional tests and they are mandatory to use for every change in ClickHouse code that can be tested that way.
+
+Each functional test sends one or multiple queries to the running ClickHouse server and compares the result with reference.
+
+Tests are located in `queries` directory. There are two subdirectories: `stateless` and `stateful`. Stateless tests run queries without any preloaded test data - they often create small synthetic datasets on the fly, within the test itself. Stateful tests require preloaded test data from CLickHouse and it is available to general public.
+
+Each test can be one of two types: `.sql` and `.sh`. `.sql` test is the simple SQL script that is piped to `clickhouse-client --multiquery --testmode`. `.sh` test is a script that is run by itself. SQL tests are generally preferable to `.sh` tests. You should use `.sh` tests only when you have to test some feature that cannot be exercised from pure SQL, such as piping some input data into `clickhouse-client` or testing `clickhouse-local`.
+
+### Running a Test Locally {#functional-test-locally}
+
+Start the ClickHouse server locally, listening on the default port (9000). To
+run, for example, the test `01428_hash_set_nan_key`, change to the repository
+folder and run the following command:
+
+```
+PATH=$PATH:<path to clickhouse-client> tests/clickhouse-test 01428_hash_set_nan_key
+```
+
+For more options, see `tests/clickhouse-test --help`. You can simply run all tests or run subset of tests filtered by substring in test name: `./clickhouse-test substring`. There are also options to run tests in parallel or in randomized order.
+
+### Adding a New Test
+
+To add new test, create a `.sql` or `.sh` file in `queries/0_stateless` directory, check it manually and then generate `.reference` file in the following way: `clickhouse-client -n --testmode < 00000_test.sql > 00000_test.reference` or `./00000_test.sh > ./00000_test.reference`.
+
+Tests should use (create, drop, etc) only tables in `test` database that is assumed to be created beforehand; also tests can use temporary tables.
+
+### Choosing the Test Name
+
+The name of the test starts with a five-digit prefix followed by a descriptive name, such as `00422_hash_function_constexpr.sql`. To choose the prefix, find the largest prefix already present in the directory, and increment it by one. In the meantime, some other tests might be added with the same numeric prefix, but this is OK and does not lead to any problems, you don't have to change it later.
+
+Some tests are marked with `zookeeper`, `shard` or `long` in their names. `zookeeper` is for tests that are using ZooKeeper. `shard` is for tests that requires server to listen `127.0.0.*`; `distributed` or `global` have the same meaning. `long` is for tests that run slightly longer that one second. You can disable these groups of tests using `--no-zookeeper`, `--no-shard` and `--no-long` options, respectively. Make sure to add a proper prefix to your test name if it needs ZooKeeper or distributed queries.
+
+### Checking for an Error that Must Occur
+
+Sometimes you want to test that a server error occurs for an incorrect query. We support special annotations for this in SQL tests, in the following form:
+```
+select x; -- { serverError 49 }
+```
+This test ensures that the server returns an error with code 49 about unknown column `x`. If there is no error, or the error is different, the test will fail. If you want to ensure that an error occurs on the client side, use `clientError` annotation instead.
+
+Do not check for a particular wording of error message, it may change in the future, and the test will needlessly break. Check only the error code. If the existing error code is not precise enough for your needs, consider adding a new one.
+
+### Testing a Distributed Query
+
+If you want to use distributed queries in functional tests, you can leverage `remote` table function with `127.0.0.{1..2}` addresses for the server to query itself; or you can use predefined test clusters in server configuration file like `test_shard_localhost`. Remember to add the words `shard` or `distributed` to the test name, so that it is run in CI in correct configurations, where the server is configured to support distributed queries.
+
+
+## Known Bugs {#known-bugs}
+
+If we know some bugs that can be easily reproduced by functional tests, we place prepared functional tests in `tests/queries/bugs` directory. These tests will be moved to `tests/queries/0_stateless` when bugs are fixed.
+
+## Integration Tests {#integration-tests}
+
+Integration tests allow testing ClickHouse in clustered configuration and ClickHouse interaction with other servers like MySQL, Postgres, MongoDB. They are useful to emulate network splits, packet drops, etc. These tests are run under Docker and create multiple containers with various software.
+
+See `tests/integration/README.md` on how to run these tests.
+
+Note that integration of ClickHouse with third-party drivers is not tested. Also, we currently do not have integration tests with our JDBC and ODBC drivers.
+
+## Unit Tests {#unit-tests}
+
+Unit tests are useful when you want to test not the ClickHouse as a whole, but a single isolated library or class. You can enable or disable build of tests with `ENABLE_TESTS` CMake option. Unit tests (and other test programs) are located in `tests` subdirectories across the code. To run unit tests, type `ninja test`. Some tests use `gtest`, but some are just programs that return non-zero exit code on test failure.
+
+It’s not necessary to have unit tests if the code is already covered by functional tests (and functional tests are usually much more simple to use).
+
+You can run individual gtest checks by calling the executable directly, for example:
+
+```bash
+$ ./src/unit_tests_dbms --gtest_filter=LocalAddress*
+```
+
+## Performance Tests {#performance-tests}
+
+Performance tests allow to measure and compare performance of some isolated part of ClickHouse on synthetic queries. Tests are located at `tests/performance`. Each test is represented by `.xml` file with description of test case. Tests are run with `docker/tests/performance-comparison` tool . See the readme file for invocation.
+
+Each test run one or multiple queries (possibly with combinations of parameters) in a loop. Some tests can contain preconditions on preloaded test dataset.
+
+If you want to improve performance of ClickHouse in some scenario, and if improvements can be observed on simple queries, it is highly recommended to write a performance test. It always makes sense to use `perf top` or other perf tools during your tests.
+
+## Test Tools and Scripts {#test-tools-and-scripts}
+
+Some programs in `tests` directory are not prepared tests, but are test tools. For example, for `Lexer` there is a tool `src/Parsers/tests/lexer` that just do tokenization of stdin and writes colorized result to stdout. You can use these kind of tools as a code examples and for exploration and manual testing.
+
+## Miscellaneous Tests {#miscellaneous-tests}
+
+There are tests for machine learned models in `tests/external_models`. These tests are not updated and must be transferred to integration tests.
+
+There is separate test for quorum inserts. This test run ClickHouse cluster on separate servers and emulate various failure cases: network split, packet drop (between ClickHouse nodes, between ClickHouse and ZooKeeper, between ClickHouse server and client, etc.), `kill -9`, `kill -STOP` and `kill -CONT` , like [Jepsen](https://aphyr.com/tags/Jepsen). Then the test checks that all acknowledged inserts was written and all rejected inserts was not.
+
+Quorum test was written by separate team before ClickHouse was open-sourced. This team no longer work with ClickHouse. Test was accidentally written in Java. For these reasons, quorum test must be rewritten and moved to integration tests.
+
+## Manual Testing {#manual-testing}
+
+When you develop a new feature, it is reasonable to also test it manually. You can do it with the following steps:
+
+Build ClickHouse. Run ClickHouse from the terminal: change directory to `programs/clickhouse-server` and run it with `./clickhouse-server`. It will use configuration (`config.xml`, `users.xml` and files within `config.d` and `users.d` directories) from the current directory by default. To connect to ClickHouse server, run `programs/clickhouse-client/clickhouse-client`.
+
+Note that all clickhouse tools (server, client, etc) are just symlinks to a single binary named `clickhouse`. You can find this binary at `programs/clickhouse`. All tools can also be invoked as `clickhouse tool` instead of `clickhouse-tool`.
+
+Alternatively you can install ClickHouse package: either stable release from ClickHouse repository or you can build package for yourself with `./release` in ClickHouse sources root. Then start the server with `sudo clickhouse start` (or stop to stop the server). Look for logs at `/etc/clickhouse-server/clickhouse-server.log`.
+
+When ClickHouse is already installed on your system, you can build a new `clickhouse` binary and replace the existing binary:
+
+``` bash
+$ sudo clickhouse stop
+$ sudo cp ./clickhouse /usr/bin/
+$ sudo clickhouse start
+```
+
+Also you can stop system clickhouse-server and run your own with the same configuration but with logging to terminal:
+
+``` bash
+$ sudo clickhouse stop
+$ sudo -u clickhouse /usr/bin/clickhouse server --config-file /etc/clickhouse-server/config.xml
+```
+
+Example with gdb:
+
+``` bash
+$ sudo -u clickhouse gdb --args /usr/bin/clickhouse server --config-file /etc/clickhouse-server/config.xml
+```
+
+If the system clickhouse-server is already running and you do not want to stop it, you can change port numbers in your `config.xml` (or override them in a file in `config.d` directory), provide appropriate data path, and run it.
+
+`clickhouse` binary has almost no dependencies and works across wide range of Linux distributions. To quick and dirty test your changes on a server, you can simply `scp` your fresh built `clickhouse` binary to your server and then run it as in examples above.
+
+## Build Tests {#build-tests}
+
+Build tests allow to check that build is not broken on various alternative configurations and on some foreign systems. These tests are automated as well.
+
+Examples:
+-   cross-compile for Darwin x86_64 (Mac OS X)
+-   cross-compile for FreeBSD x86_64
+-   cross-compile for Linux AArch64
+-   build on Ubuntu with libraries from system packages (discouraged)
+-   build with shared linking of libraries (discouraged)
+
+For example, build with system packages is bad practice, because we cannot guarantee what exact version of packages a system will have. But this is really needed by Debian maintainers. For this reason we at least have to support this variant of build. Another example: shared linking is a common source of trouble, but it is needed for some enthusiasts.
+
+Though we cannot run all tests on all variant of builds, we want to check at least that various build variants are not broken. For this purpose we use build tests.
+
+We also test that there are no translation units that are too long to compile or require too much RAM.
+
+We also test that there are no too large stack frames.
+
+## Testing for Protocol Compatibility {#testing-for-protocol-compatibility}
+
+When we extend ClickHouse network protocol, we test manually that old clickhouse-client works with new clickhouse-server and new clickhouse-client works with old clickhouse-server (simply by running binaries from corresponding packages).
+
+We also test some cases automatically with integrational tests:
+- if data written by old version of ClickHouse can be successfully read by the new version;
+- do distributed queries work in a cluster with different ClickHouse versions.
+
+## Help from the Compiler {#help-from-the-compiler}
+
+Main ClickHouse code (that is located in `dbms` directory) is built with `-Wall -Wextra -Werror` and with some additional enabled warnings. Although these options are not enabled for third-party libraries.
+
+Clang has even more useful warnings - you can look for them with `-Weverything` and pick something to default build.
+
+For production builds, clang is used, but we also test make gcc builds. For development, clang is usually more convenient to use. You can build on your own machine with debug mode (to save battery of your laptop), but please note that compiler is able to generate more warnings with `-O3` due to better control flow and inter-procedure analysis. When building with clang in debug mode, debug version of `libc++` is used that allows to catch more errors at runtime.
+
+## Sanitizers {#sanitizers}
+
+### Address sanitizer
+We run functional, integration, stress and unit tests under ASan on per-commit basis.
+
+### Thread sanitizer
+We run functional, integration, stress and unit tests under TSan on per-commit basis.
+
+### Memory sanitizer
+We run functional, integration, stress and unit tests under MSan on per-commit basis.
+
+### Undefined behaviour sanitizer
+We run functional, integration, stress and unit tests under UBSan on per-commit basis. The code of some third-party libraries is not sanitized for UB.
+
+### Valgrind (Memcheck)
+We used to run functional tests under Valgrind overnight, but don't do it anymore. It takes multiple hours. Currently there is one known false positive in `re2` library, see [this article](https://research.swtch.com/sparse).
+
+## Fuzzing {#fuzzing}
+
+ClickHouse fuzzing is implemented both using [libFuzzer](https://llvm.org/docs/LibFuzzer.html) and random SQL queries.
+All the fuzz testing should be performed with sanitizers (Address and Undefined).
+
+LibFuzzer is used for isolated fuzz testing of library code. Fuzzers are implemented as part of test code and have “_fuzzer” name postfixes.
+Fuzzer example can be found at `src/Parsers/tests/lexer_fuzzer.cpp`. LibFuzzer-specific configs, dictionaries and corpus are stored at `tests/fuzz`.
+We encourage you to write fuzz tests for every functionality that handles user input.
+
+Fuzzers are not built by default. To build fuzzers both `-DENABLE_FUZZING=1` and `-DENABLE_TESTS=1` options should be set.
+We recommend to disable Jemalloc while building fuzzers. Configuration used to integrate ClickHouse fuzzing to
+Google OSS-Fuzz can be found at `docker/fuzz`.
+
+We also use simple fuzz test to generate random SQL queries and to check that the server does not die executing them.
+You can find it in `00746_sql_fuzzy.pl`. This test should be run continuously (overnight and longer).
+
+We also use sophisticated AST-based query fuzzer that is able to find huge amount of corner cases. It does random permutations and substitutions in queries AST. It remembers AST nodes from previous tests to use them for fuzzing of subsequent tests while processing them in random order. You can learn more about this fuzzer in [this blog article](https://clickhouse.com/blog/en/2021/fuzzing-clickhouse/).
+
+## Stress test
+
+Stress tests are another case of fuzzing. It runs all functional tests in parallel in random order with a single server. Results of the tests are not checked.
+
+It is checked that:
+- server does not crash, no debug or sanitizer traps are triggered;
+- there are no deadlocks;
+- the database structure is consistent;
+- server can successfully stop after the test and start again without exceptions.
+
+There are five variants (Debug, ASan, TSan, MSan, UBSan).
+
+## Thread Fuzzer
+
+Thread Fuzzer (please don't mix up with Thread Sanitizer) is another kind of fuzzing that allows to randomize thread order of execution. It helps to find even more special cases.
+
+## Security Audit
+
+Our Security Team did some basic overview of ClickHouse capabilities from the security standpoint.
+
+## Static Analyzers {#static-analyzers}
+
+We run `clang-tidy` on per-commit basis. `clang-static-analyzer` checks are also enabled. `clang-tidy` is also used for some style checks.
+
+We have evaluated `clang-tidy`, `Coverity`, `cppcheck`, `PVS-Studio`, `tscancode`, `CodeQL`. You will find instructions for usage in `tests/instructions/` directory. 
+
+If you use `CLion` as an IDE, you can leverage some `clang-tidy` checks out of the box.
+
+We also use `shellcheck` for static analysis of shell scripts.
+
+## Hardening {#hardening}
+
+In debug build we are using custom allocator that does ASLR of user-level allocations.
+
+We also manually protect memory regions that are expected to be readonly after allocation.
+
+In debug build we also involve a customization of libc that ensures that no "harmful" (obsolete, insecure, not thread-safe) functions are called.
+
+Debug assertions are used extensively.
+
+In debug build, if exception with "logical error" code (implies a bug) is being thrown, the program is terminated prematurally. It allows to use exceptions in release build but make it an assertion in debug build.
+
+Debug version of jemalloc is used for debug builds.
+Debug version of libc++ is used for debug builds.
+
+## Runtime Integrity Checks
+
+Data stored on disk is checksummed. Data in MergeTree tables is checksummed in three ways simultaneously* (compressed data blocks, uncompressed data blocks, the total checksum across blocks). Data transferred over network between client and server or between servers is also checksummed. Replication ensures bit-identical data on replicas.
+
+It is required to protect from faulty hardware (bit rot on storage media, bit flips in RAM on server, bit flips in RAM of network controller, bit flips in RAM of network switch, bit flips in RAM of client, bit flips on the wire). Note that bit flips are common and likely to occur even for ECC RAM and in presense of TCP checksums (if you manage to run thousands of servers processing petabytes of data each day). [See the video (russian)](https://www.youtube.com/watch?v=ooBAQIe0KlQ).
+
+ClickHouse provides diagnostics that will help ops engineers to find faulty hardware.
+
+\* and it is not slow.
+
+## Code Style {#code-style}
+
+Code style rules are described [here](style.md).
+
+To check for some common style violations, you can use `utils/check-style` script.
+
+To force proper style of your code, you can use `clang-format`. File `.clang-format` is located at the sources root. It mostly corresponding with our actual code style. But it’s not recommended to apply `clang-format` to existing files because it makes formatting worse. You can use `clang-format-diff` tool that you can find in clang source repository.
+
+Alternatively you can try `uncrustify` tool to reformat your code. Configuration is in `uncrustify.cfg` in the sources root. It is less tested than `clang-format`.
+
+`CLion` has its own code formatter that has to be tuned for our code style.
+
+We also use `codespell` to find typos in code. It is automated as well.
+
+## Test Coverage {#test-coverage}
+
+We also track test coverage but only for functional tests and only for clickhouse-server. It is performed on daily basis.
+
+## Tests for Tests
+
+There is automated check for flaky tests. It runs all new tests 100 times (for functional tests) or 10 times (for integration tests). If at least single time the test failed, it is considered flaky.
+
+## Testflows
+
+[Testflows](https://testflows.com/) is an enterprise-grade open-source testing framework, which is used to test a subset of ClickHouse.
+
+## Test Automation {#test-automation}
+
+We run tests with [GitHub Actions](https://github.com/features/actions).
+
+Build jobs and tests are run in Sandbox on per commit basis. Resulting packages and test results are published in GitHub and can be downloaded by direct links. Artifacts are stored for several months. When you send a pull request on GitHub, we tag it as “can be tested” and our CI system will build ClickHouse packages (release, debug, with address sanitizer, etc) for you.
+
+We do not use Travis CI due to the limit on time and computational power.
+We do not use Jenkins. It was used before and now we are happy we are not using Jenkins.
+
+[Original article](https://clickhouse.com/docs/en/development/tests/) <!--hide-->
diff --git a/docs/en/reference/engines/_category_.yml b/docs/en/reference/engines/_category_.yml
new file mode 100644
index 00000000000..a82c53bc65e
--- /dev/null
+++ b/docs/en/reference/engines/_category_.yml
@@ -0,0 +1,8 @@
+position: 30
+label: 'Database & Table Engines'
+collapsible: true
+collapsed: true
+link:
+  type: generated-index
+  title: Database & Table Engines
+  slug: /en/table-engines
\ No newline at end of file
diff --git a/docs/en/reference/engines/database-engines/atomic.md b/docs/en/reference/engines/database-engines/atomic.md
new file mode 100644
index 00000000000..878307121aa
--- /dev/null
+++ b/docs/en/reference/engines/database-engines/atomic.md
@@ -0,0 +1,61 @@
+---
+sidebar_label: Atomic
+sidebar_position: 10
+---
+
+# Atomic 
+
+It supports non-blocking [DROP TABLE](#drop-detach-table) and [RENAME TABLE](#rename-table) queries and atomic [EXCHANGE TABLES](#exchange-tables) queries. `Atomic` database engine is used by default.
+
+## Creating a Database {#creating-a-database}
+
+``` sql
+CREATE DATABASE test [ENGINE = Atomic];
+```
+
+## Specifics and recommendations {#specifics-and-recommendations}
+
+### Table UUID {#table-uuid}
+
+All tables in database `Atomic` have persistent [UUID](../../sql-reference/data-types/uuid.md) and store data in directory `/clickhouse_path/store/xxx/xxxyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy/`, where `xxxyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy` is UUID of the table.
+Usually, the UUID is generated automatically, but the user can also explicitly specify the UUID in the same way when creating the table (this is not recommended). 
+
+For example:
+
+```sql
+CREATE TABLE name UUID '28f1c61c-2970-457a-bffe-454156ddcfef' (n UInt64) ENGINE = ...;
+```
+
+:::note
+You can use the [show_table_uuid_in_table_create_query_if_not_nil](../../operations/settings/settings.md#show_table_uuid_in_table_create_query_if_not_nil) setting to display the UUID with the `SHOW CREATE` query. 
+:::
+
+### RENAME TABLE {#rename-table}
+
+[RENAME](../../sql-reference/statements/rename.md) queries are performed without changing the UUID or moving table data. These queries do not wait for the completion of queries using the table and are executed instantly.
+
+### DROP/DETACH TABLE {#drop-detach-table}
+
+On `DROP TABLE` no data is removed, database `Atomic` just marks table as dropped by moving metadata to `/clickhouse_path/metadata_dropped/` and notifies background thread. Delay before final table data deletion is specified by the [database_atomic_delay_before_drop_table_sec](../../operations/server-configuration-parameters/settings.md#database_atomic_delay_before_drop_table_sec) setting.
+You can specify synchronous mode using `SYNC` modifier. Use the [database_atomic_wait_for_drop_and_detach_synchronously](../../operations/settings/settings.md#database_atomic_wait_for_drop_and_detach_synchronously) setting to do this. In this case `DROP` waits for running `SELECT`, `INSERT` and other queries which are using the table to finish. Table will be actually removed when it's not in use.
+
+### EXCHANGE TABLES/DICTIONARIES {#exchange-tables}
+
+[EXCHANGE](../../sql-reference/statements/exchange.md) query swaps tables or dictionaries atomically. For instance, instead of this non-atomic operation:
+
+```sql
+RENAME TABLE new_table TO tmp, old_table TO new_table, tmp TO old_table;
+```
+you can use one atomic query:
+
+``` sql
+EXCHANGE TABLES new_table AND old_table;
+```
+
+### ReplicatedMergeTree in Atomic Database {#replicatedmergetree-in-atomic-database}
+
+For [ReplicatedMergeTree](../table-engines/mergetree-family/replication.md#table_engines-replication) tables, it is recommended not to specify engine parameters - path in ZooKeeper and replica name. In this case, configuration parameters [default_replica_path](../../operations/server-configuration-parameters/settings.md#default_replica_path) and [default_replica_name](../../operations/server-configuration-parameters/settings.md#default_replica_name) will be used. If you want to specify engine parameters explicitly, it is recommended to use `{uuid}` macros. This is useful so that unique paths are automatically generated for each table in ZooKeeper.
+
+## See Also
+
+-   [system.databases](../../operations/system-tables/databases.md) system table
diff --git a/docs/en/reference/engines/database-engines/index.md b/docs/en/reference/engines/database-engines/index.md
new file mode 100644
index 00000000000..0cee580abcd
--- /dev/null
+++ b/docs/en/reference/engines/database-engines/index.md
@@ -0,0 +1,25 @@
+---
+toc_folder_title: Database Engines
+toc_priority: 27
+toc_title: Introduction
+---
+
+# Database Engines {#database-engines}
+
+Database engines allow you to work with tables. By default, ClickHouse uses the [Atomic](../../engines/database-engines/atomic.md) database engine, which provides configurable [table engines](../../engines/table-engines/index.md) and an [SQL dialect](../../sql-reference/syntax.md).
+
+Here is a complete list of available database engines. Follow the links for more details:
+
+-   [Atomic](../../engines/database-engines/atomic.md)
+
+-   [MySQL](../../engines/database-engines/mysql.md)
+
+-   [MaterializedMySQL](../../engines/database-engines/materialized-mysql.md)
+
+-   [Lazy](../../engines/database-engines/lazy.md)
+
+-   [PostgreSQL](../../engines/database-engines/postgresql.md)
+
+-   [Replicated](../../engines/database-engines/replicated.md)
+
+-   [SQLite](../../engines/database-engines/sqlite.md)
diff --git a/docs/en/reference/engines/database-engines/lazy.md b/docs/en/reference/engines/database-engines/lazy.md
new file mode 100644
index 00000000000..b95ade19df4
--- /dev/null
+++ b/docs/en/reference/engines/database-engines/lazy.md
@@ -0,0 +1,16 @@
+---
+sidebar_label: Lazy
+sidebar_position: 20
+---
+
+# Lazy {#lazy}
+
+Keeps tables in RAM only `expiration_time_in_seconds` seconds after last access. Can be used only with \*Log tables.
+
+It’s optimized for storing many small \*Log tables, for which there is a long time interval between accesses.
+
+## Creating a Database {#creating-a-database}
+
+    CREATE DATABASE testlazy ENGINE = Lazy(expiration_time_in_seconds);
+
+[Original article](https://clickhouse.com/docs/en/database_engines/lazy/) <!--hide-->
diff --git a/docs/en/reference/engines/database-engines/materialized-mysql.md b/docs/en/reference/engines/database-engines/materialized-mysql.md
new file mode 100644
index 00000000000..df072682097
--- /dev/null
+++ b/docs/en/reference/engines/database-engines/materialized-mysql.md
@@ -0,0 +1,290 @@
+---
+sidebar_label: MaterializedMySQL
+sidebar_position: 70
+---
+
+# [experimental] MaterializedMySQL 
+
+:::warning
+This is an experimental feature that should not be used in production.
+:::
+
+Creates a ClickHouse database with all the tables existing in MySQL, and all the data in those tables. The ClickHouse server works as MySQL replica. It reads `binlog` and performs DDL and DML queries.
+
+## Creating a Database {#creating-a-database}
+
+``` sql
+CREATE DATABASE [IF NOT EXISTS] db_name [ON CLUSTER cluster]
+ENGINE = MaterializedMySQL('host:port', ['database' | database], 'user', 'password') [SETTINGS ...]
+[TABLE OVERRIDE table1 (...), TABLE OVERRIDE table2 (...)]
+```
+
+**Engine Parameters**
+
+-   `host:port` — MySQL server endpoint.
+-   `database` — MySQL database name.
+-   `user` — MySQL user.
+-   `password` — User password.
+
+**Engine Settings**
+
+-   `max_rows_in_buffer` — Maximum number of rows that data is allowed to cache in memory (for single table and the cache data unable to query). When this number is exceeded, the data will be materialized. Default: `65 505`.
+-   `max_bytes_in_buffer` —  Maximum number of bytes that data is allowed to cache in memory (for single table and the cache data unable to query). When this number is exceeded, the data will be materialized. Default: `1 048 576`.
+-   `max_flush_data_time` — Maximum number of milliseconds that data is allowed to cache in memory (for database and the cache data unable to query). When this time is exceeded, the data will be materialized. Default: `1000`.
+-   `max_wait_time_when_mysql_unavailable` — Retry interval when MySQL is not available (milliseconds). Negative value disables retry. Default: `1000`.
+-   `allows_query_when_mysql_lost` — Allows to query a materialized table when MySQL is lost. Default: `0` (`false`).
+-   `materialized_mysql_tables_list` — a comma-separated list of mysql database tables, which will be replicated by MaterializedMySQL database engine. Default value: empty list — means whole tables will be replicated.
+
+```sql
+CREATE DATABASE mysql ENGINE = MaterializedMySQL('localhost:3306', 'db', 'user', '***')
+     SETTINGS
+        allows_query_when_mysql_lost=true,
+        max_wait_time_when_mysql_unavailable=10000;
+```
+
+**Settings on MySQL-server Side**
+
+For the correct work of `MaterializedMySQL`, there are few mandatory `MySQL`-side configuration settings that must be set:
+
+- `default_authentication_plugin = mysql_native_password` since `MaterializedMySQL` can only authorize with this method.
+- `gtid_mode = on` since GTID based logging is a mandatory for providing correct `MaterializedMySQL` replication.
+
+:::note 
+While turning on `gtid_mode` you should also specify `enforce_gtid_consistency = on`.
+:::
+
+## Virtual Columns {#virtual-columns}
+
+When working with the `MaterializedMySQL` database engine, [ReplacingMergeTree](../../engines/table-engines/mergetree-family/replacingmergetree.md) tables are used with virtual `_sign` and `_version` columns.
+
+- `_version` — Transaction counter. Type [UInt64](../../sql-reference/data-types/int-uint.md).
+- `_sign` — Deletion mark. Type [Int8](../../sql-reference/data-types/int-uint.md). Possible values:
+    - `1` — Row is not deleted,
+    - `-1` — Row is deleted.
+
+## Data Types Support {#data_types-support}
+
+| MySQL                   | ClickHouse                                                   |
+|-------------------------|--------------------------------------------------------------|
+| TINY                    | [Int8](../../sql-reference/data-types/int-uint.md)           |
+| SHORT                   | [Int16](../../sql-reference/data-types/int-uint.md)          |
+| INT24                   | [Int32](../../sql-reference/data-types/int-uint.md)          |
+| LONG                    | [UInt32](../../sql-reference/data-types/int-uint.md)         |
+| LONGLONG                | [UInt64](../../sql-reference/data-types/int-uint.md)         |
+| FLOAT                   | [Float32](../../sql-reference/data-types/float.md)           |
+| DOUBLE                  | [Float64](../../sql-reference/data-types/float.md)           |
+| DECIMAL, NEWDECIMAL     | [Decimal](../../sql-reference/data-types/decimal.md)         |
+| DATE, NEWDATE           | [Date](../../sql-reference/data-types/date.md)               |
+| DATETIME, TIMESTAMP     | [DateTime](../../sql-reference/data-types/datetime.md)       |
+| DATETIME2, TIMESTAMP2   | [DateTime64](../../sql-reference/data-types/datetime64.md)   |
+| YEAR                    | [UInt16](../../sql-reference/data-types/int-uint.md)         |
+| TIME                    | [Int64](../../sql-reference/data-types/int-uint.md)          |
+| ENUM                    | [Enum](../../sql-reference/data-types/enum.md)               |
+| STRING                  | [String](../../sql-reference/data-types/string.md)           |
+| VARCHAR, VAR_STRING     | [String](../../sql-reference/data-types/string.md)           |
+| BLOB                    | [String](../../sql-reference/data-types/string.md)           |
+| GEOMETRY                | [String](../../sql-reference/data-types/string.md)           |
+| BINARY                  | [FixedString](../../sql-reference/data-types/fixedstring.md) |
+| BIT                     | [UInt64](../../sql-reference/data-types/int-uint.md)         |
+| SET                     | [UInt64](../../sql-reference/data-types/int-uint.md)         |
+
+[Nullable](../../sql-reference/data-types/nullable.md) is supported.
+
+The data of TIME type in MySQL is converted to microseconds in ClickHouse.
+
+Other types are not supported. If MySQL table contains a column of such type, ClickHouse throws exception "Unhandled data type" and stops replication.
+
+## Specifics and Recommendations {#specifics-and-recommendations}
+
+### Compatibility Restrictions {#compatibility-restrictions}
+
+Apart of the data types limitations there are few restrictions comparing to `MySQL` databases, that should be resolved before replication will be possible:
+
+- Each table in `MySQL` should contain `PRIMARY KEY`.
+
+- Replication for tables, those are containing rows with `ENUM` field values out of range (specified in `ENUM` signature) will not work.
+
+### DDL Queries {#ddl-queries}
+
+MySQL DDL queries are converted into the corresponding ClickHouse DDL queries ([ALTER](../../sql-reference/statements/alter/index.md), [CREATE](../../sql-reference/statements/create/index.md), [DROP](../../sql-reference/statements/drop.md), [RENAME](../../sql-reference/statements/rename.md)). If ClickHouse cannot parse some DDL query, the query is ignored.
+
+### Data Replication {#data-replication}
+
+`MaterializedMySQL` does not support direct `INSERT`, `DELETE` and `UPDATE` queries. However, they are supported in terms of data replication:
+
+- MySQL `INSERT` query is converted into `INSERT` with `_sign=1`.
+
+- MySQL `DELETE` query is converted into `INSERT` with `_sign=-1`.
+
+- MySQL `UPDATE` query is converted into `INSERT` with `_sign=-1` and `INSERT` with `_sign=1` if the primary key has been changed, or
+  `INSERT` with `_sign=1` if not.
+
+### Selecting from MaterializedMySQL Tables {#select}
+
+`SELECT` query from `MaterializedMySQL` tables has some specifics:
+
+- If `_version` is not specified in the `SELECT` query, the
+  [FINAL](../../sql-reference/statements/select/from.md#select-from-final) modifier is used, so only rows with
+  `MAX(_version)` are returned for each primary key value.
+
+- If `_sign` is not specified in the `SELECT` query, `WHERE _sign=1` is used by default. So the deleted rows are not
+  included into the result set.
+
+- The result includes columns comments in case they exist in MySQL database tables.
+
+### Index Conversion {#index-conversion}
+
+MySQL `PRIMARY KEY` and `INDEX` clauses are converted into `ORDER BY` tuples in ClickHouse tables.
+
+ClickHouse has only one physical order, which is determined by `ORDER BY` clause. To create a new physical order, use
+[materialized views](../../sql-reference/statements/create/view.md#materialized).
+
+**Notes**
+
+- Rows with `_sign=-1` are not deleted physically from the tables.
+- Cascade `UPDATE/DELETE` queries are not supported by the `MaterializedMySQL` engine, as they are not visible in the
+  MySQL binlog.
+- Replication can be easily broken.
+- Manual operations on database and tables are forbidden.
+- `MaterializedMySQL` is affected by the [optimize_on_insert](../../operations/settings/settings.md#optimize-on-insert)
+  setting. Data is merged in the corresponding table in the `MaterializedMySQL` database when a table in the MySQL
+  server changes.
+
+### Table Overrides {#table-overrides}
+
+Table overrides can be used to customize the ClickHouse DDL queries, allowing you to make schema optimizations for your
+application. This is especially useful for controlling partitioning, which is important for the overall performance of
+MaterializedMySQL.
+
+These are the schema conversion manipulations you can do with table overrides for MaterializedMySQL:
+
+ * Modify column type. Must be compatible with the original type, or replication will fail. For example,
+   you can modify a UInt32 column to UInt64, but you can not modify a String column to Array(String).
+ * Modify [column TTL](../table-engines/mergetree-family/mergetree/#mergetree-column-ttl).
+ * Modify [column compression codec](../../sql-reference/statements/create/table/#codecs).
+ * Add [ALIAS columns](../../sql-reference/statements/create/table/#alias).
+ * Add [skipping indexes](../table-engines/mergetree-family/mergetree/#table_engine-mergetree-data_skipping-indexes)
+ * Add [projections](../table-engines/mergetree-family/mergetree/#projections). Note that projection optimizations are
+   disabled when using `SELECT ... FINAL` (which MaterializedMySQL does by default), so their utility is limited here.
+   `INDEX ... TYPE hypothesis` as [described in the v21.12 blog post]](https://clickhouse.com/blog/en/2021/clickhouse-v21.12-released/)
+   may be more useful in this case.
+ * Modify [PARTITION BY](../table-engines/mergetree-family/custom-partitioning-key/)
+ * Modify [ORDER BY](../table-engines/mergetree-family/mergetree/#mergetree-query-clauses)
+ * Modify [PRIMARY KEY](../table-engines/mergetree-family/mergetree/#mergetree-query-clauses)
+ * Add [SAMPLE BY](../table-engines/mergetree-family/mergetree/#mergetree-query-clauses)
+ * Add [table TTL](../table-engines/mergetree-family/mergetree/#mergetree-query-clauses)
+
+```sql
+CREATE DATABASE db_name ENGINE = MaterializedMySQL(...)
+[SETTINGS ...]
+[TABLE OVERRIDE table_name (
+    [COLUMNS (
+        [col_name [datatype] [ALIAS expr] [CODEC(...)] [TTL expr], ...]
+        [INDEX index_name expr TYPE indextype[(...)] GRANULARITY val, ...]
+        [PROJECTION projection_name (SELECT <COLUMN LIST EXPR> [GROUP BY] [ORDER BY]), ...]
+    )]
+    [ORDER BY expr]
+    [PRIMARY KEY expr]
+    [PARTITION BY expr]
+    [SAMPLE BY expr]
+    [TTL expr]
+), ...]
+```
+
+Example:
+
+```sql
+CREATE DATABASE db_name ENGINE = MaterializedMySQL(...)
+TABLE OVERRIDE table1 (
+    COLUMNS (
+        userid UUID,
+        category LowCardinality(String),
+        timestamp DateTime CODEC(Delta, Default)
+    )
+    PARTITION BY toYear(timestamp)
+),
+TABLE OVERRIDE table2 (
+    COLUMNS (
+        client_ip String TTL created + INTERVAL 72 HOUR
+    )
+    SAMPLE BY ip_hash
+)
+```
+
+The `COLUMNS` list is sparse; existing columns are modified as specified, extra ALIAS columns are added. It is not
+possible to add ordinary or MATERIALIZED columns.  Modified columns with a different type must be assignable from the
+original type. There is currently no validation of this or similar issues when the `CREATE DATABASE` query executes, so
+extra care needs to be taken.
+
+You may specify overrides for tables that do not exist yet.
+
+:::warning
+It is easy to break replication with table overrides if not used with care. For example:
+    
+* If an ALIAS column is added with a table override, and a column with the same name is later added to the source
+  MySQL table, the converted ALTER TABLE query in ClickHouse will fail and replication stops.
+* It is currently possible to add overrides that reference nullable columns where not-nullable are required, such as in
+  `ORDER BY` or `PARTITION BY`. This will cause CREATE TABLE queries that will fail, also causing replication to stop.
+:::
+
+## Examples of Use {#examples-of-use}
+
+Queries in MySQL:
+
+``` sql
+mysql> CREATE DATABASE db;
+mysql> CREATE TABLE db.test (a INT PRIMARY KEY, b INT);
+mysql> INSERT INTO db.test VALUES (1, 11), (2, 22);
+mysql> DELETE FROM db.test WHERE a=1;
+mysql> ALTER TABLE db.test ADD COLUMN c VARCHAR(16);
+mysql> UPDATE db.test SET c='Wow!', b=222;
+mysql> SELECT * FROM test;
+```
+
+```text
+┌─a─┬───b─┬─c────┐
+│ 2 │ 222 │ Wow! │
+└───┴─────┴──────┘
+```
+
+Database in ClickHouse, exchanging data with the MySQL server:
+
+The database and the table created:
+
+``` sql
+CREATE DATABASE mysql ENGINE = MaterializedMySQL('localhost:3306', 'db', 'user', '***');
+SHOW TABLES FROM mysql;
+```
+
+``` text
+┌─name─┐
+│ test │
+└──────┘
+```
+
+After inserting data:
+
+``` sql
+SELECT * FROM mysql.test;
+```
+
+``` text
+┌─a─┬──b─┐
+│ 1 │ 11 │
+│ 2 │ 22 │
+└───┴────┘
+```
+
+After deleting data, adding the column and updating:
+
+``` sql
+SELECT * FROM mysql.test;
+```
+
+``` text
+┌─a─┬───b─┬─c────┐
+│ 2 │ 222 │ Wow! │
+└───┴─────┴──────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/engines/database-engines/materialized-mysql/) <!--hide-->
diff --git a/docs/en/reference/engines/database-engines/materialized-postgresql.md b/docs/en/reference/engines/database-engines/materialized-postgresql.md
new file mode 100644
index 00000000000..ff8f7b192e0
--- /dev/null
+++ b/docs/en/reference/engines/database-engines/materialized-postgresql.md
@@ -0,0 +1,279 @@
+---
+sidebar_label: MaterializedPostgreSQL
+sidebar_position: 60
+---
+
+# [experimental] MaterializedPostgreSQL {#materialize-postgresql}
+
+Creates a ClickHouse database with tables from PostgreSQL database. Firstly, database with engine `MaterializedPostgreSQL` creates a snapshot of PostgreSQL database and loads required tables. Required tables can include any subset of tables from any subset of schemas from specified database. Along with the snapshot database engine acquires LSN and once initial dump of tables is performed - it starts pulling updates from WAL. After database is created, newly added tables to PostgreSQL database are not automatically added to replication. They have to be added manually with `ATTACH TABLE db.table` query.
+
+Replication is implemented with PostgreSQL Logical Replication Protocol, which does not allow to replicate DDL, but allows to know whether replication breaking changes happened (column type changes, adding/removing columns). Such changes are detected and according tables stop receiving updates. Such tables can be automatically reloaded in the background in case required setting is turned on (can be used starting from 22.1). Safest way for now is to use `ATTACH`/ `DETACH` queries to reload table completely. If DDL does not break replication (for example, renaming a column) table will still receive updates (insertion is done by position).
+
+## Creating a Database {#creating-a-database}
+
+``` sql
+CREATE DATABASE [IF NOT EXISTS] db_name [ON CLUSTER cluster]
+ENGINE = MaterializedPostgreSQL('host:port', 'database', 'user', 'password') [SETTINGS ...]
+```
+
+**Engine Parameters**
+
+-   `host:port` — PostgreSQL server endpoint.
+-   `database` — PostgreSQL database name.
+-   `user` — PostgreSQL user.
+-   `password` — User password.
+
+## Example of Use {#example-of-use}
+
+``` sql
+CREATE DATABASE postgres_db
+ENGINE = MaterializedPostgreSQL('postgres1:5432', 'postgres_database', 'postgres_user', 'postgres_password');
+
+SHOW TABLES FROM postgres_db;
+
+┌─name───┐
+│ table1 │
+└────────┘
+
+SELECT * FROM postgresql_db.postgres_table;
+```
+
+## Dynamically adding new tables to replication {#dynamically-adding-table-to-replication}
+
+After `MaterializedPostgreSQL` database is created, it does not automatically detect new tables in according PostgreSQL database. Such tables can be added manually:
+
+``` sql
+ATTACH TABLE postgres_database.new_table;
+```
+
+:::warning
+Before version 22.1, adding a table to replication left an unremoved temporary replication slot (named `{db_name}_ch_replication_slot_tmp`). If attaching tables in ClickHouse version before 22.1, make sure to delete it manually (`SELECT pg_drop_replication_slot('{db_name}_ch_replication_slot_tmp')`). Otherwise disk usage will grow. This issue is fixed in 22.1.
+:::
+
+## Dynamically removing tables from replication {#dynamically-removing-table-from-replication}
+
+It is possible to remove specific tables from replication:
+
+``` sql
+DETACH TABLE postgres_database.table_to_remove;
+```
+
+## PostgreSQL schema {#schema}
+
+PostgreSQL [schema](https://www.postgresql.org/docs/9.1/ddl-schemas.html) can be configured in 3 ways (starting from version 21.12).
+
+1. One schema for one `MaterializedPostgreSQL` database engine. Requires to use setting `materialized_postgresql_schema`.
+Tables are accessed via table name only:
+
+``` sql
+CREATE DATABASE postgres_database
+ENGINE = MaterializedPostgreSQL('postgres1:5432', 'postgres_database', 'postgres_user', 'postgres_password')
+SETTINGS materialized_postgresql_schema = 'postgres_schema';
+
+SELECT * FROM postgres_database.table1;
+```
+
+2. Any number of schemas with specified set of tables for one `MaterializedPostgreSQL` database engine. Requires to use setting `materialized_postgresql_tables_list`. Each table is written along with its schema.
+Tables are accessed via schema name and table name at the same time:
+
+``` sql
+CREATE DATABASE database1
+ENGINE = MaterializedPostgreSQL('postgres1:5432', 'postgres_database', 'postgres_user', 'postgres_password')
+SETTINGS materialized_postgresql_tables_list = 'schema1.table1,schema2.table2,schema1.table3',
+         materialized_postgresql_tables_list_with_schema = 1;
+
+SELECT * FROM database1.`schema1.table1`;
+SELECT * FROM database1.`schema2.table2`;
+```
+
+But in this case all tables in `materialized_postgresql_tables_list` must be written with its schema name.
+Requires `materialized_postgresql_tables_list_with_schema = 1`.
+
+Warning: for this case dots in table name are not allowed.
+
+3. Any number of schemas with full set of tables for one `MaterializedPostgreSQL` database engine. Requires to use setting `materialized_postgresql_schema_list`.
+
+``` sql
+CREATE DATABASE database1
+ENGINE = MaterializedPostgreSQL('postgres1:5432', 'postgres_database', 'postgres_user', 'postgres_password')
+SETTINGS materialized_postgresql_schema_list = 'schema1,schema2,schema3';
+
+SELECT * FROM database1.`schema1.table1`;
+SELECT * FROM database1.`schema1.table2`;
+SELECT * FROM database1.`schema2.table2`;
+```
+
+Warning: for this case dots in table name are not allowed.
+
+
+## Requirements {#requirements}
+
+1. The [wal_level](https://www.postgresql.org/docs/current/runtime-config-wal.html) setting must have a value `logical` and `max_replication_slots` parameter must have a value at least `2` in the PostgreSQL config file.
+
+2. Each replicated table must have one of the following [replica identity](https://www.postgresql.org/docs/10/sql-altertable.html#SQL-CREATETABLE-REPLICA-IDENTITY):
+
+-   primary key (by default)
+
+-   index
+
+``` bash
+postgres# CREATE TABLE postgres_table (a Integer NOT NULL, b Integer, c Integer NOT NULL, d Integer, e Integer NOT NULL);
+postgres# CREATE unique INDEX postgres_table_index on postgres_table(a, c, e);
+postgres# ALTER TABLE postgres_table REPLICA IDENTITY USING INDEX postgres_table_index;
+```
+
+The primary key is always checked first. If it is absent, then the index, defined as replica identity index, is checked.
+If the index is used as a replica identity, there has to be only one such index in a table.
+You can check what type is used for a specific table with the following command:
+
+``` bash
+postgres# SELECT CASE relreplident
+          WHEN 'd' THEN 'default'
+          WHEN 'n' THEN 'nothing'
+          WHEN 'f' THEN 'full'
+          WHEN 'i' THEN 'index'
+       END AS replica_identity
+FROM pg_class
+WHERE oid = 'postgres_table'::regclass;
+```
+
+:::warning 
+Replication of [**TOAST**](https://www.postgresql.org/docs/9.5/storage-toast.html) values is not supported. The default value for the data type will be used.
+:::
+
+## Settings {#settings}
+
+1. `materialized_postgresql_tables_list` {#materialized-postgresql-tables-list}
+
+    Sets a comma-separated list of PostgreSQL database tables, which will be replicated via [MaterializedPostgreSQL](../../engines/database-engines/materialized-postgresql.md) database engine.
+
+    Default value: empty list — means whole PostgreSQL database will be replicated.
+
+2. `materialized_postgresql_schema` {#materialized-postgresql-schema}
+
+    Default value: empty string. (Default schema is used)
+
+3. `materialized_postgresql_schema_list` {#materialized-postgresql-schema-list}
+
+    Default value: empty list. (Default schema is used)
+
+4. `materialized_postgresql_allow_automatic_update` {#materialized-postgresql-allow-automatic-update}
+
+    Do not use this setting before 22.1 version.
+
+    Allows reloading table in the background, when schema changes are detected. DDL queries on the PostgreSQL side are not replicated via ClickHouse [MaterializedPostgreSQL](../../engines/database-engines/materialized-postgresql.md) engine, because it is not allowed with PostgreSQL logical replication protocol, but the fact of DDL changes is detected transactionally. In this case, the default behaviour is to stop replicating those tables once DDL is detected. However, if this setting is enabled, then, instead of stopping the replication of those tables, they will be reloaded in the background via database snapshot without data losses and replication will continue for them.
+
+    Possible values:
+
+    -   0 — The table is not automatically updated in the background, when schema changes are detected.
+    -   1 — The table is automatically updated in the background, when schema changes are detected.
+
+    Default value: `0`.
+
+5. `materialized_postgresql_max_block_size` {#materialized-postgresql-max-block-size}
+
+    Sets the number of rows collected in memory before flushing data into PostgreSQL database table.
+
+    Possible values:
+
+    -   Positive integer.
+
+    Default value: `65536`.
+
+6. `materialized_postgresql_replication_slot` {#materialized-postgresql-replication-slot}
+
+    A user-created replication slot. Must be used together with `materialized_postgresql_snapshot`.
+
+7. `materialized_postgresql_snapshot` {#materialized-postgresql-snapshot}
+
+    A text string identifying a snapshot, from which [initial dump of PostgreSQL tables](../../engines/database-engines/materialized-postgresql.md) will be performed. Must be used together with `materialized_postgresql_replication_slot`.
+
+    ``` sql
+    CREATE DATABASE database1
+    ENGINE = MaterializedPostgreSQL('postgres1:5432', 'postgres_database', 'postgres_user', 'postgres_password')
+    SETTINGS materialized_postgresql_tables_list = 'table1,table2,table3';
+
+    SELECT * FROM database1.table1;
+    ```
+
+    The settings can be changed, if necessary, using a DDL query. But it is impossible to change the setting `materialized_postgresql_tables_list`. To update the list of tables in this setting use the `ATTACH TABLE` query.
+
+    ``` sql
+    ALTER DATABASE postgres_database MODIFY SETTING materialized_postgresql_max_block_size = <new_size>;
+    ```
+
+## Notes {#notes}
+
+### Failover of the logical replication slot {#logical-replication-slot-failover}
+
+Logical Replication Slots which exist on the primary are not available on standby replicas.
+So if there is a failover, new primary (the old physical standby) won’t be aware of any slots which were existing with old primary. This will lead to a broken replication from PostgreSQL.
+A solution to this is to manage replication slots yourself and define a permanent replication slot (some information can be found [here](https://patroni.readthedocs.io/en/latest/SETTINGS.html)). You'll need to pass slot name via `materialized_postgresql_replication_slot` setting, and it has to be exported with `EXPORT SNAPSHOT` option. The snapshot identifier needs to be passed via `materialized_postgresql_snapshot` setting.
+
+Please note that this should be used only if it is actually needed. If there is no real need for that or full understanding why, then it is better to allow the table engine to create and manage its own replication slot.
+
+**Example (from [@bchrobot](https://github.com/bchrobot))**
+
+1. Configure replication slot in PostgreSQL.
+
+    ```yaml
+    apiVersion: "acid.zalan.do/v1"
+    kind: postgresql
+    metadata:
+      name: acid-demo-cluster
+    spec:
+      numberOfInstances: 2
+      postgresql:
+        parameters:
+          wal_level: logical
+      patroni:
+        slots:
+          clickhouse_sync:
+            type: logical
+            database: demodb
+            plugin: pgoutput
+    ```
+
+2. Wait for replication slot to be ready, then begin a transaction and export the transaction snapshot identifier:
+
+    ```sql
+    BEGIN;
+    SELECT pg_export_snapshot();
+    ```
+
+3. In ClickHouse create database:
+
+    ```sql
+    CREATE DATABASE demodb
+    ENGINE = MaterializedPostgreSQL('postgres1:5432', 'postgres_database', 'postgres_user', 'postgres_password')
+    SETTINGS
+      materialized_postgresql_replication_slot = 'clickhouse_sync',
+      materialized_postgresql_snapshot = '0000000A-0000023F-3',
+      materialized_postgresql_tables_list = 'table1,table2,table3';
+    ```
+
+4. End the PostgreSQL transaction once replication to ClickHouse DB is confirmed. Verify that replication continues after failover:
+
+    ```bash
+    kubectl exec acid-demo-cluster-0 -c postgres -- su postgres -c 'patronictl failover --candidate acid-demo-cluster-1 --force'
+    ```
+
+### Required permissions
+
+1. [CREATE PUBLICATION](https://postgrespro.ru/docs/postgresql/14/sql-createpublication) -- create query privilege.
+
+2. [CREATE_REPLICATION_SLOT](https://postgrespro.ru/docs/postgrespro/10/protocol-replication#PROTOCOL-REPLICATION-CREATE-SLOT) -- replication privelege.
+
+3. [pg_drop_replication_slot](https://postgrespro.ru/docs/postgrespro/9.5/functions-admin#functions-replication) -- replication privilege or superuser.
+
+4. [DROP PUBLICATION](https://postgrespro.ru/docs/postgresql/10/sql-droppublication) -- owner of publication (`username` in MaterializedPostgreSQL engine itself).
+
+It is possible to avoid executing `2` and `3` commands and having those permissions. Use settings `materialized_postgresql_replication_slot` and `materialized_postgresql_snapshot`. But with much care.
+
+Access to tables:
+
+1. pg_publication
+
+2. pg_replication_slots
+
+3. pg_publication_tables
diff --git a/docs/en/reference/engines/database-engines/mysql.md b/docs/en/reference/engines/database-engines/mysql.md
new file mode 100644
index 00000000000..89a0786a9ec
--- /dev/null
+++ b/docs/en/reference/engines/database-engines/mysql.md
@@ -0,0 +1,151 @@
+---
+sidebar_position: 50
+sidebar_label: MySQL
+---
+
+# MySQL 
+
+Allows to connect to databases on a remote MySQL server and perform `INSERT` and `SELECT` queries to exchange data between ClickHouse and MySQL.
+
+The `MySQL` database engine translate queries to the MySQL server so you can perform operations such as `SHOW TABLES` or `SHOW CREATE TABLE`.
+
+You cannot perform the following queries:
+
+-   `RENAME`
+-   `CREATE TABLE`
+-   `ALTER`
+
+## Creating a Database {#creating-a-database}
+
+``` sql
+CREATE DATABASE [IF NOT EXISTS] db_name [ON CLUSTER cluster]
+ENGINE = MySQL('host:port', ['database' | database], 'user', 'password')
+```
+
+**Engine Parameters**
+
+-   `host:port` — MySQL server address.
+-   `database` — Remote database name.
+-   `user` — MySQL user.
+-   `password` — User password.
+
+## Data Types Support {#data_types-support}
+
+| MySQL                            | ClickHouse                                                   |
+|----------------------------------|--------------------------------------------------------------|
+| UNSIGNED TINYINT                 | [UInt8](../../sql-reference/data-types/int-uint.md)          |
+| TINYINT                          | [Int8](../../sql-reference/data-types/int-uint.md)           |
+| UNSIGNED SMALLINT                | [UInt16](../../sql-reference/data-types/int-uint.md)         |
+| SMALLINT                         | [Int16](../../sql-reference/data-types/int-uint.md)          |
+| UNSIGNED INT, UNSIGNED MEDIUMINT | [UInt32](../../sql-reference/data-types/int-uint.md)         |
+| INT, MEDIUMINT                   | [Int32](../../sql-reference/data-types/int-uint.md)          |
+| UNSIGNED BIGINT                  | [UInt64](../../sql-reference/data-types/int-uint.md)         |
+| BIGINT                           | [Int64](../../sql-reference/data-types/int-uint.md)          |
+| FLOAT                            | [Float32](../../sql-reference/data-types/float.md)           |
+| DOUBLE                           | [Float64](../../sql-reference/data-types/float.md)           |
+| DATE                             | [Date](../../sql-reference/data-types/date.md)               |
+| DATETIME, TIMESTAMP              | [DateTime](../../sql-reference/data-types/datetime.md)       |
+| BINARY                           | [FixedString](../../sql-reference/data-types/fixedstring.md) |
+
+All other MySQL data types are converted into [String](../../sql-reference/data-types/string.md).
+
+[Nullable](../../sql-reference/data-types/nullable.md) is supported.
+
+## Global Variables Support {#global-variables-support}
+
+For better compatibility you may address global variables in MySQL style, as `@@identifier`.
+
+These variables are supported:
+- `version`
+- `max_allowed_packet`
+
+:::warning
+By now these variables are stubs and don't correspond to anything.
+:::
+
+Example:
+
+``` sql
+SELECT @@version;
+```
+
+## Examples of Use {#examples-of-use}
+
+Table in MySQL:
+
+``` text
+mysql> USE test;
+Database changed
+
+mysql> CREATE TABLE `mysql_table` (
+    ->   `int_id` INT NOT NULL AUTO_INCREMENT,
+    ->   `float` FLOAT NOT NULL,
+    ->   PRIMARY KEY (`int_id`));
+Query OK, 0 rows affected (0,09 sec)
+
+mysql> insert into mysql_table (`int_id`, `float`) VALUES (1,2);
+Query OK, 1 row affected (0,00 sec)
+
+mysql> select * from mysql_table;
++------+-----+
+| int_id | value |
++------+-----+
+|      1 |     2 |
++------+-----+
+1 row in set (0,00 sec)
+```
+
+Database in ClickHouse, exchanging data with the MySQL server:
+
+``` sql
+CREATE DATABASE mysql_db ENGINE = MySQL('localhost:3306', 'test', 'my_user', 'user_password')
+```
+
+``` sql
+SHOW DATABASES
+```
+
+``` text
+┌─name─────┐
+│ default  │
+│ mysql_db │
+│ system   │
+└──────────┘
+```
+
+``` sql
+SHOW TABLES FROM mysql_db
+```
+
+``` text
+┌─name─────────┐
+│  mysql_table │
+└──────────────┘
+```
+
+``` sql
+SELECT * FROM mysql_db.mysql_table
+```
+
+``` text
+┌─int_id─┬─value─┐
+│      1 │     2 │
+└────────┴───────┘
+```
+
+``` sql
+INSERT INTO mysql_db.mysql_table VALUES (3,4)
+```
+
+``` sql
+SELECT * FROM mysql_db.mysql_table
+```
+
+``` text
+┌─int_id─┬─value─┐
+│      1 │     2 │
+│      3 │     4 │
+└────────┴───────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/database_engines/mysql/) <!--hide-->
diff --git a/docs/en/reference/engines/database-engines/postgresql.md b/docs/en/reference/engines/database-engines/postgresql.md
new file mode 100644
index 00000000000..bc5e93d0923
--- /dev/null
+++ b/docs/en/reference/engines/database-engines/postgresql.md
@@ -0,0 +1,139 @@
+---
+sidebar_position: 40
+sidebar_label: PostgreSQL
+---
+
+# PostgreSQL {#postgresql}
+
+Allows to connect to databases on a remote [PostgreSQL](https://www.postgresql.org) server. Supports read and write operations (`SELECT` and `INSERT` queries) to exchange data between ClickHouse and PostgreSQL.
+
+Gives the real-time access to table list and table structure from remote PostgreSQL with the help of `SHOW TABLES` and `DESCRIBE TABLE` queries.
+
+Supports table structure modifications (`ALTER TABLE ... ADD|DROP COLUMN`). If `use_table_cache` parameter (see the Engine Parameters below) it set to `1`, the table structure is cached and not checked for being modified, but can be updated with `DETACH` and `ATTACH` queries.
+
+## Creating a Database {#creating-a-database}
+
+``` sql
+CREATE DATABASE test_database
+ENGINE = PostgreSQL('host:port', 'database', 'user', 'password'[, `schema`, `use_table_cache`]);
+```
+
+**Engine Parameters**
+
+-   `host:port` — PostgreSQL server address.
+-   `database` — Remote database name.
+-   `user` — PostgreSQL user.
+-   `password` — User password.
+-   `schema` — PostgreSQL schema.
+-   `use_table_cache` —  Defines if the database table structure is cached or not. Optional. Default value: `0`.
+
+## Data Types Support {#data_types-support}
+
+| PostgerSQL       | ClickHouse                                                   |
+|------------------|--------------------------------------------------------------|
+| DATE             | [Date](../../sql-reference/data-types/date.md)               |
+| TIMESTAMP        | [DateTime](../../sql-reference/data-types/datetime.md)       |
+| REAL             | [Float32](../../sql-reference/data-types/float.md)           |
+| DOUBLE           | [Float64](../../sql-reference/data-types/float.md)           |
+| DECIMAL, NUMERIC | [Decimal](../../sql-reference/data-types/decimal.md)       |
+| SMALLINT         | [Int16](../../sql-reference/data-types/int-uint.md)          |
+| INTEGER          | [Int32](../../sql-reference/data-types/int-uint.md)          |
+| BIGINT           | [Int64](../../sql-reference/data-types/int-uint.md)          |
+| SERIAL           | [UInt32](../../sql-reference/data-types/int-uint.md)         |
+| BIGSERIAL        | [UInt64](../../sql-reference/data-types/int-uint.md)         |
+| TEXT, CHAR       | [String](../../sql-reference/data-types/string.md)           |
+| INTEGER          | Nullable([Int32](../../sql-reference/data-types/int-uint.md))|
+| ARRAY            | [Array](../../sql-reference/data-types/array.md)             |
+
+
+## Examples of Use {#examples-of-use}
+
+Database in ClickHouse, exchanging data with the PostgreSQL server:
+
+``` sql
+CREATE DATABASE test_database
+ENGINE = PostgreSQL('postgres1:5432', 'test_database', 'postgres', 'mysecretpassword', 1);
+```
+
+``` sql
+SHOW DATABASES;
+```
+
+``` text
+┌─name──────────┐
+│ default       │
+│ test_database │
+│ system        │
+└───────────────┘
+```
+
+``` sql
+SHOW TABLES FROM test_database;
+```
+
+``` text
+┌─name───────┐
+│ test_table │
+└────────────┘
+```
+
+Reading data from the PostgreSQL table:
+
+``` sql
+SELECT * FROM test_database.test_table;
+```
+
+``` text
+┌─id─┬─value─┐
+│  1 │     2 │
+└────┴───────┘
+```
+
+Writing data to the PostgreSQL table:
+
+``` sql
+INSERT INTO test_database.test_table VALUES (3,4);
+SELECT * FROM test_database.test_table;
+```
+
+``` text
+┌─int_id─┬─value─┐
+│      1 │     2 │
+│      3 │     4 │
+└────────┴───────┘
+```
+
+Consider the table structure was modified in PostgreSQL:
+
+``` sql
+postgre> ALTER TABLE test_table ADD COLUMN data Text
+```
+
+As the `use_table_cache` parameter was set to `1` when the database was created, the table structure in ClickHouse was cached and therefore not modified:
+
+``` sql
+DESCRIBE TABLE test_database.test_table;
+```
+``` text
+┌─name───┬─type──────────────┐
+│ id     │ Nullable(Integer) │
+│ value  │ Nullable(Integer) │
+└────────┴───────────────────┘
+```
+
+After detaching the table and attaching it again, the structure was updated:
+
+``` sql
+DETACH TABLE test_database.test_table;
+ATTACH TABLE test_database.test_table;
+DESCRIBE TABLE test_database.test_table;
+```
+``` text
+┌─name───┬─type──────────────┐
+│ id     │ Nullable(Integer) │
+│ value  │ Nullable(Integer) │
+│ data   │ Nullable(String)  │
+└────────┴───────────────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/database-engines/postgresql/) <!--hide-->
diff --git a/docs/en/reference/engines/database-engines/replicated.md b/docs/en/reference/engines/database-engines/replicated.md
new file mode 100644
index 00000000000..63d955dc889
--- /dev/null
+++ b/docs/en/reference/engines/database-engines/replicated.md
@@ -0,0 +1,123 @@
+---
+sidebar_position: 30
+sidebar_label: Replicated
+---
+
+# [experimental] Replicated {#replicated}
+
+The engine is based on the [Atomic](../../engines/database-engines/atomic.md) engine. It supports replication of metadata via DDL log being written to ZooKeeper and executed on all of the replicas for a given database.
+
+One ClickHouse server can have multiple replicated databases running and updating at the same time. But there can't be multiple replicas of the same replicated database.
+
+## Creating a Database {#creating-a-database}
+``` sql
+    CREATE DATABASE testdb ENGINE = Replicated('zoo_path', 'shard_name', 'replica_name') [SETTINGS ...]
+```
+
+**Engine Parameters**
+
+-   `zoo_path` — ZooKeeper path. The same ZooKeeper path corresponds to the same database.
+-   `shard_name` — Shard name. Database replicas are grouped into shards by `shard_name`.
+-   `replica_name` — Replica name. Replica names must be different for all replicas of the same shard.
+
+:::warning    
+For [ReplicatedMergeTree](../table-engines/mergetree-family/replication.md#table_engines-replication) tables if no arguments provided, then default arguments are used: `/clickhouse/tables/{uuid}/{shard}` and `{replica}`. These can be changed in the server settings [default_replica_path](../../operations/server-configuration-parameters/settings.md#default_replica_path) and [default_replica_name](../../operations/server-configuration-parameters/settings.md#default_replica_name). Macro `{uuid}` is unfolded to table's uuid, `{shard}` and `{replica}` are unfolded to values from server config, not from database engine arguments. But in the future, it will be possible to use `shard_name` and `replica_name` of Replicated database.
+:::
+
+## Specifics and Recommendations {#specifics-and-recommendations}
+
+DDL queries with `Replicated` database work in a similar way to [ON CLUSTER](../../sql-reference/distributed-ddl.md) queries, but with minor differences.
+
+First, the DDL request tries to execute on the initiator (the host that originally received the request from the user). If the request is not fulfilled, then the user immediately receives an error, other hosts do not try to fulfill it. If the request has been successfully completed on the initiator, then all other hosts will automatically retry until they complete it. The initiator will try to wait for the query to be completed on other hosts (no longer than [distributed_ddl_task_timeout](../../operations/settings/settings.md#distributed_ddl_task_timeout)) and will return a table with the query execution statuses on each host.
+
+The behavior in case of errors is regulated by the [distributed_ddl_output_mode](../../operations/settings/settings.md#distributed_ddl_output_mode) setting, for a `Replicated` database it is better to set it to `null_status_on_timeout` — i.e. if some hosts did not have time to execute the request for [distributed_ddl_task_timeout](../../operations/settings/settings.md#distributed_ddl_task_timeout), then do not throw an exception, but show the `NULL` status for them in the table.
+
+The [system.clusters](../../operations/system-tables/clusters.md) system table contains a cluster named like the replicated database, which consists of all replicas of the database. This cluster is updated automatically when creating/deleting replicas, and it can be used for [Distributed](../../engines/table-engines/special/distributed.md#distributed) tables.
+
+When creating a new replica of the database, this replica creates tables by itself. If the replica has been unavailable for a long time and has lagged behind the replication log — it checks its local metadata with the current metadata in ZooKeeper, moves the extra tables with data to a separate non-replicated database (so as not to accidentally delete anything superfluous), creates the missing tables, updates the table names if they have been renamed. The data is replicated at the `ReplicatedMergeTree` level, i.e. if the table is not replicated, the data will not be replicated (the database is responsible only for metadata).
+
+[`ALTER TABLE ATTACH|FETCH|DROP|DROP DETACHED|DETACH PARTITION|PART`](../../sql-reference/statements/alter/partition.md) queries are allowed but not replicated. The database engine will only add/fetch/remove the partition/part to the current replica. However, if the table itself uses a Replicated table engine, then the data will be replicated after using `ATTACH`.
+
+## Usage Example {#usage-example}
+
+Creating a cluster with three hosts:
+
+``` sql
+node1 :) CREATE DATABASE r ENGINE=Replicated('some/path/r','shard1','replica1');
+node2 :) CREATE DATABASE r ENGINE=Replicated('some/path/r','shard1','other_replica');
+node3 :) CREATE DATABASE r ENGINE=Replicated('some/path/r','other_shard','{replica}');
+```
+
+Running the DDL-query:
+
+``` sql
+CREATE TABLE r.rmt (n UInt64) ENGINE=ReplicatedMergeTree ORDER BY n;
+```
+
+``` text
+┌─────hosts────────────┬──status─┬─error─┬─num_hosts_remaining─┬─num_hosts_active─┐
+│ shard1|replica1      │    0    │       │          2          │        0         │
+│ shard1|other_replica │    0    │       │          1          │        0         │
+│ other_shard|r1       │    0    │       │          0          │        0         │
+└──────────────────────┴─────────┴───────┴─────────────────────┴──────────────────┘
+```
+
+Showing the system table:
+
+``` sql
+SELECT cluster, shard_num, replica_num, host_name, host_address, port, is_local
+FROM system.clusters WHERE cluster='r';
+```
+
+``` text
+┌─cluster─┬─shard_num─┬─replica_num─┬─host_name─┬─host_address─┬─port─┬─is_local─┐
+│ r       │     1     │      1      │   node3   │  127.0.0.1   │ 9002 │     0    │
+│ r       │     2     │      1      │   node2   │  127.0.0.1   │ 9001 │     0    │
+│ r       │     2     │      2      │   node1   │  127.0.0.1   │ 9000 │     1    │
+└─────────┴───────────┴─────────────┴───────────┴──────────────┴──────┴──────────┘
+```
+
+Creating a distributed table and inserting the data:
+
+``` sql
+node2 :) CREATE TABLE r.d (n UInt64) ENGINE=Distributed('r','r','rmt', n % 2);
+node3 :) INSERT INTO r SELECT * FROM numbers(10);
+node1 :) SELECT materialize(hostName()) AS host, groupArray(n) FROM r.d GROUP BY host;
+```
+
+``` text
+┌─hosts─┬─groupArray(n)─┐
+│ node1 │  [1,3,5,7,9]  │
+│ node2 │  [0,2,4,6,8]  │
+└───────┴───────────────┘
+```
+
+Adding replica on the one more host:
+
+``` sql
+node4 :) CREATE DATABASE r ENGINE=Replicated('some/path/r','other_shard','r2');
+```
+
+The cluster configuration will look like this:
+
+``` text
+┌─cluster─┬─shard_num─┬─replica_num─┬─host_name─┬─host_address─┬─port─┬─is_local─┐
+│ r       │     1     │      1      │   node3   │  127.0.0.1   │ 9002 │     0    │
+│ r       │     1     │      2      │   node4   │  127.0.0.1   │ 9003 │     0    │
+│ r       │     2     │      1      │   node2   │  127.0.0.1   │ 9001 │     0    │
+│ r       │     2     │      2      │   node1   │  127.0.0.1   │ 9000 │     1    │
+└─────────┴───────────┴─────────────┴───────────┴──────────────┴──────┴──────────┘
+```
+
+The distributed table also will get data from the new host:
+
+```sql
+node2 :) SELECT materialize(hostName()) AS host, groupArray(n) FROM r.d GROUP BY host;
+```
+
+```text
+┌─hosts─┬─groupArray(n)─┐
+│ node2 │  [1,3,5,7,9]  │
+│ node4 │  [0,2,4,6,8]  │
+└───────┴───────────────┘
+```
\ No newline at end of file
diff --git a/docs/en/reference/engines/database-engines/sqlite.md b/docs/en/reference/engines/database-engines/sqlite.md
new file mode 100644
index 00000000000..2f8b44c9a09
--- /dev/null
+++ b/docs/en/reference/engines/database-engines/sqlite.md
@@ -0,0 +1,80 @@
+---
+sidebar_position: 55
+sidebar_label: SQLite
+---
+
+# SQLite {#sqlite}
+
+Allows to connect to [SQLite](https://www.sqlite.org/index.html) database and perform `INSERT` and `SELECT` queries to exchange data between ClickHouse and SQLite. 
+
+## Creating a Database {#creating-a-database}
+
+``` sql
+    CREATE DATABASE sqlite_database 
+    ENGINE = SQLite('db_path')
+```
+
+**Engine Parameters**
+
+-   `db_path` — Path to a file with SQLite database.
+    
+## Data Types Support {#data_types-support}
+
+|  SQLite   | ClickHouse                                              |
+|---------------|---------------------------------------------------------|
+| INTEGER       | [Int32](../../sql-reference/data-types/int-uint.md)     |
+| REAL          | [Float32](../../sql-reference/data-types/float.md)      |
+| TEXT          | [String](../../sql-reference/data-types/string.md)      |
+| BLOB          | [String](../../sql-reference/data-types/string.md)      |
+
+## Specifics and Recommendations {#specifics-and-recommendations}
+
+SQLite stores the entire database (definitions, tables, indices, and the data itself) as a single cross-platform file on a host machine. During writing SQLite locks the entire database file, therefore write operations are performed sequentially. Read operations can be multitasked.
+SQLite does not require service management (such as startup scripts) or access control based on `GRANT` and passwords. Access control is handled by means of file-system permissions given to the database file itself.
+
+## Usage Example {#usage-example}
+
+Database in ClickHouse, connected to the SQLite:
+
+``` sql
+CREATE DATABASE sqlite_db ENGINE = SQLite('sqlite.db');
+SHOW TABLES FROM sqlite_db;
+```
+
+``` text
+┌──name───┐
+│ table1  │
+│ table2  │  
+└─────────┘
+```
+
+Shows the tables:
+
+``` sql
+SELECT * FROM sqlite_db.table1;
+```
+
+``` text
+┌─col1──┬─col2─┐
+│ line1 │    1 │
+│ line2 │    2 │
+│ line3 │    3 │
+└───────┴──────┘
+```
+Inserting data into SQLite table from ClickHouse table:
+
+``` sql
+CREATE TABLE clickhouse_table(`col1` String,`col2` Int16) ENGINE = MergeTree() ORDER BY col2;
+INSERT INTO clickhouse_table VALUES ('text',10);
+INSERT INTO sqlite_db.table1 SELECT * FROM clickhouse_table;
+SELECT * FROM sqlite_db.table1;
+```
+
+``` text
+┌─col1──┬─col2─┐
+│ line1 │    1 │
+│ line2 │    2 │
+│ line3 │    3 │
+│ text  │   10 │
+└───────┴──────┘
+```
diff --git a/docs/en/reference/engines/table-engines/index.md b/docs/en/reference/engines/table-engines/index.md
new file mode 100644
index 00000000000..09e0147bbf7
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/index.md
@@ -0,0 +1,89 @@
+---
+toc_folder_title: Table Engines
+toc_priority: 26
+toc_title: Introduction
+---
+
+# Table Engines {#table_engines}
+
+The table engine (type of table) determines:
+
+-   How and where data is stored, where to write it to, and where to read it from.
+-   Which queries are supported, and how.
+-   Concurrent data access.
+-   Use of indexes, if present.
+-   Whether multithreaded request execution is possible.
+-   Data replication parameters.
+
+## Engine Families {#engine-families}
+
+### MergeTree {#mergetree}
+
+The most universal and functional table engines for high-load tasks. The property shared by these engines is quick data insertion with subsequent background data processing. `MergeTree` family engines support data replication (with [Replicated\*](../../engines/table-engines/mergetree-family/replication.md#table_engines-replication) versions of engines), partitioning, secondary data-skipping indexes, and other features not supported in other engines.
+
+Engines in the family:
+
+-   [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md#mergetree)
+-   [ReplacingMergeTree](../../engines/table-engines/mergetree-family/replacingmergetree.md#replacingmergetree)
+-   [SummingMergeTree](../../engines/table-engines/mergetree-family/summingmergetree.md#summingmergetree)
+-   [AggregatingMergeTree](../../engines/table-engines/mergetree-family/aggregatingmergetree.md#aggregatingmergetree)
+-   [CollapsingMergeTree](../../engines/table-engines/mergetree-family/collapsingmergetree.md#table_engine-collapsingmergetree)
+-   [VersionedCollapsingMergeTree](../../engines/table-engines/mergetree-family/versionedcollapsingmergetree.md#versionedcollapsingmergetree)
+-   [GraphiteMergeTree](../../engines/table-engines/mergetree-family/graphitemergetree.md#graphitemergetree)
+
+### Log {#log}
+
+Lightweight [engines](../../engines/table-engines/log-family/index.md) with minimum functionality. They’re the most effective when you need to quickly write many small tables (up to approximately 1 million rows) and read them later as a whole.
+
+Engines in the family:
+
+-   [TinyLog](../../engines/table-engines/log-family/tinylog.md#tinylog)
+-   [StripeLog](../../engines/table-engines/log-family/stripelog.md#stripelog)
+-   [Log](../../engines/table-engines/log-family/log.md#log)
+
+### Integration Engines {#integration-engines}
+
+Engines for communicating with other data storage and processing systems.
+
+Engines in the family:
+
+
+-   [ODBC](../../engines/table-engines/integrations/odbc.md)
+-   [JDBC](../../engines/table-engines/integrations/jdbc.md)
+-   [MySQL](../../engines/table-engines/integrations/mysql.md)
+-   [MongoDB](../../engines/table-engines/integrations/mongodb.md)
+-   [HDFS](../../engines/table-engines/integrations/hdfs.md)
+-   [S3](../../engines/table-engines/integrations/s3.md)
+-   [Kafka](../../engines/table-engines/integrations/kafka.md)
+-   [EmbeddedRocksDB](../../engines/table-engines/integrations/embedded-rocksdb.md)
+-   [RabbitMQ](../../engines/table-engines/integrations/rabbitmq.md)
+-   [PostgreSQL](../../engines/table-engines/integrations/postgresql.md)
+
+### Special Engines {#special-engines}
+
+Engines in the family:
+
+-   [Distributed](../../engines/table-engines/special/distributed.md#distributed)
+-   [MaterializedView](../../engines/table-engines/special/materializedview.md#materializedview)
+-   [Dictionary](../../engines/table-engines/special/dictionary.md#dictionary)
+-   [Merge](../../engines/table-engines/special/merge.md#merge)
+-   [File](../../engines/table-engines/special/file.md#file)
+-   [Null](../../engines/table-engines/special/null.md#null)
+-   [Set](../../engines/table-engines/special/set.md#set)
+-   [Join](../../engines/table-engines/special/join.md#join)
+-   [URL](../../engines/table-engines/special/url.md#table_engines-url)
+-   [View](../../engines/table-engines/special/view.md#table_engines-view)
+-   [Memory](../../engines/table-engines/special/memory.md#memory)
+-   [Buffer](../../engines/table-engines/special/buffer.md#buffer)
+
+## Virtual Columns {#table_engines-virtual_columns}
+
+Virtual column is an integral table engine attribute that is defined in the engine source code.
+
+You shouldn’t specify virtual columns in the `CREATE TABLE` query and you can’t see them in `SHOW CREATE TABLE` and `DESCRIBE TABLE` query results. Virtual columns are also read-only, so you can’t insert data into virtual columns.
+
+To select data from a virtual column, you must specify its name in the `SELECT` query. `SELECT *` does not return values from virtual columns.
+
+If you create a table with a column that has the same name as one of the table virtual columns, the virtual column becomes inaccessible. We do not recommend doing this. To help avoid conflicts, virtual column names are usually prefixed with an underscore.
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/ExternalDistributed.md b/docs/en/reference/engines/table-engines/integrations/ExternalDistributed.md
new file mode 100644
index 00000000000..c9aae1934db
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/ExternalDistributed.md
@@ -0,0 +1,56 @@
+---
+sidebar_position: 12
+sidebar_label: ExternalDistributed
+---
+
+# ExternalDistributed {#externaldistributed}
+
+The `ExternalDistributed` engine allows to perform `SELECT` queries on data that is stored on a remote servers MySQL or PostgreSQL. Accepts [MySQL](../../../engines/table-engines/integrations/mysql.md) or [PostgreSQL](../../../engines/table-engines/integrations/postgresql.md) engines as an argument so sharding is possible.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1] [TTL expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2] [TTL expr2],
+    ...
+) ENGINE = ExternalDistributed('engine', 'host:port', 'database', 'table', 'user', 'password');
+```
+
+See a detailed description of the [CREATE TABLE](../../../sql-reference/statements/create/table.md#create-table-query) query.
+
+The table structure can differ from the original table structure:
+
+-   Column names should be the same as in the original table, but you can use just some of these columns and in any order.
+-   Column types may differ from those in the original table. ClickHouse tries to [cast](../../../sql-reference/functions/type-conversion-functions.md#type_conversion_function-cast) values to the ClickHouse data types.
+
+**Engine Parameters**
+
+-   `engine` — The table engine `MySQL` or `PostgreSQL`.
+-   `host:port` — MySQL or PostgreSQL server address.
+-   `database` — Remote database name.
+-   `table` — Remote table name.
+-   `user` — User name.
+-   `password` — User password.
+
+## Implementation Details {#implementation-details}
+
+Supports multiple replicas that must be listed by `|` and shards must be listed by `,`. For example:
+
+```sql
+CREATE TABLE test_shards (id UInt32, name String, age UInt32, money UInt32) ENGINE = ExternalDistributed('MySQL', `mysql{1|2}:3306,mysql{3|4}:3306`, 'clickhouse', 'test_replicas', 'root', 'clickhouse');
+```
+
+When specifying replicas, one of the available replicas is selected for each of the shards when reading. If the connection fails, the next replica is selected, and so on for all the replicas. If the connection attempt fails for all the replicas, the attempt is repeated the same way several times.
+
+You can specify any number of shards and any number of replicas for each shard.
+
+**See Also**
+
+-   [MySQL table engine](../../../engines/table-engines/integrations/mysql.md)
+-   [PostgreSQL table engine](../../../engines/table-engines/integrations/postgresql.md)
+-   [Distributed table engine](../../../engines/table-engines/special/distributed.md)
+
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/ExternalDistributed/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/embedded-rocksdb.md b/docs/en/reference/engines/table-engines/integrations/embedded-rocksdb.md
new file mode 100644
index 00000000000..701d190f022
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/embedded-rocksdb.md
@@ -0,0 +1,84 @@
+---
+sidebar_position: 9
+sidebar_label: EmbeddedRocksDB
+---
+
+# EmbeddedRocksDB Engine {#EmbeddedRocksDB-engine}
+
+This engine allows integrating ClickHouse with [rocksdb](http://rocksdb.org/).
+
+## Creating a Table {#table_engine-EmbeddedRocksDB-creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = EmbeddedRocksDB PRIMARY KEY(primary_key_name)
+```
+
+Required parameters:
+
+- `primary_key_name` – any column name in the column list.
+- `primary key` must be specified, it supports only one column in the primary key. The primary key will be serialized in binary as a `rocksdb key`.
+- columns other than the primary key will be serialized in binary as `rocksdb` value in corresponding order.
+- queries with key `equals` or `in` filtering will be optimized to multi keys lookup from `rocksdb`.
+
+Example:
+
+``` sql
+CREATE TABLE test
+(
+    `key` String,
+    `v1` UInt32,
+    `v2` String,
+    `v3` Float32
+)
+ENGINE = EmbeddedRocksDB
+PRIMARY KEY key
+```
+
+## Metrics
+
+There is also `system.rocksdb` table, that expose rocksdb statistics:
+
+```sql
+SELECT
+    name,
+    value
+FROM system.rocksdb
+
+┌─name──────────────────────┬─value─┐
+│ no.file.opens             │     1 │
+│ number.block.decompressed │     1 │
+└───────────────────────────┴───────┘
+```
+
+## Configuration
+
+You can also change any [rocksdb options](https://github.com/facebook/rocksdb/wiki/Option-String-and-Option-Map) using config:
+
+```xml
+<rocksdb>
+    <options>
+        <max_background_jobs>8</max_background_jobs>
+    </options>
+    <column_family_options>
+        <num_levels>2</num_levels>
+    </column_family_options>
+    <tables>
+        <table>
+            <name>TABLE</name>
+            <options>
+                <max_background_jobs>8</max_background_jobs>
+            </options>
+            <column_family_options>
+                <num_levels>2</num_levels>
+            </column_family_options>
+        </table>
+    </tables>
+</rocksdb>
+```
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/embedded-rocksdb/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/hdfs.md b/docs/en/reference/engines/table-engines/integrations/hdfs.md
new file mode 100644
index 00000000000..503bd779abf
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/hdfs.md
@@ -0,0 +1,230 @@
+---
+sidebar_position: 6
+sidebar_label: HDFS
+---
+
+# HDFS {#table_engines-hdfs}
+
+This engine provides integration with the [Apache Hadoop](https://en.wikipedia.org/wiki/Apache_Hadoop) ecosystem by allowing to manage data on [HDFS](https://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-hdfs/HdfsDesign.html) via ClickHouse. This engine is similar to the [File](../../../engines/table-engines/special/file.md#table_engines-file) and [URL](../../../engines/table-engines/special/url.md#table_engines-url) engines, but provides Hadoop-specific features.
+
+## Usage {#usage}
+
+``` sql
+ENGINE = HDFS(URI, format)
+```
+
+**Engine Parameters**
+
+- `URI` - whole file URI in HDFS. The path part of `URI` may contain globs. In this case the table would be readonly.
+-  `format` - specifies one of the available file formats. To perform
+`SELECT` queries, the format must be supported for input, and to perform
+`INSERT` queries – for output. The available formats are listed in the
+[Formats](../../../interfaces/formats.md#formats) section.
+
+**Example:**
+
+**1.** Set up the `hdfs_engine_table` table:
+
+``` sql
+CREATE TABLE hdfs_engine_table (name String, value UInt32) ENGINE=HDFS('hdfs://hdfs1:9000/other_storage', 'TSV')
+```
+
+**2.** Fill file:
+
+``` sql
+INSERT INTO hdfs_engine_table VALUES ('one', 1), ('two', 2), ('three', 3)
+```
+
+**3.** Query the data:
+
+``` sql
+SELECT * FROM hdfs_engine_table LIMIT 2
+```
+
+``` text
+┌─name─┬─value─┐
+│ one  │     1 │
+│ two  │     2 │
+└──────┴───────┘
+```
+
+## Implementation Details {#implementation-details}
+
+-   Reads and writes can be parallel.
+-   [Zero-copy](../../../operations/storing-data.md#zero-copy) replication is supported.  
+-   Not supported:
+    -   `ALTER` and `SELECT...SAMPLE` operations.
+    -   Indexes.
+
+**Globs in path**
+
+Multiple path components can have globs. For being processed file should exists and matches to the whole path pattern. Listing of files determines during `SELECT` (not at `CREATE` moment).
+
+-   `*` — Substitutes any number of any characters except `/` including empty string.
+-   `?` — Substitutes any single character.
+-   `{some_string,another_string,yet_another_one}` — Substitutes any of strings `'some_string', 'another_string', 'yet_another_one'`.
+-   `{N..M}` — Substitutes any number in range from N to M including both borders.
+
+Constructions with `{}` are similar to the [remote](../../../sql-reference/table-functions/remote.md) table function.
+
+**Example**
+
+1.  Suppose we have several files in TSV format with the following URIs on HDFS:
+
+    -  'hdfs://hdfs1:9000/some_dir/some_file_1'
+    -  'hdfs://hdfs1:9000/some_dir/some_file_2'
+    -  'hdfs://hdfs1:9000/some_dir/some_file_3'
+    -  'hdfs://hdfs1:9000/another_dir/some_file_1'
+    -  'hdfs://hdfs1:9000/another_dir/some_file_2'
+    -  'hdfs://hdfs1:9000/another_dir/some_file_3'
+
+1.  There are several ways to make a table consisting of all six files:
+
+<!-- -->
+
+``` sql
+CREATE TABLE table_with_range (name String, value UInt32) ENGINE = HDFS('hdfs://hdfs1:9000/{some,another}_dir/some_file_{1..3}', 'TSV')
+```
+
+Another way:
+
+``` sql
+CREATE TABLE table_with_question_mark (name String, value UInt32) ENGINE = HDFS('hdfs://hdfs1:9000/{some,another}_dir/some_file_?', 'TSV')
+```
+
+Table consists of all the files in both directories (all files should satisfy format and schema described in query):
+
+``` sql
+CREATE TABLE table_with_asterisk (name String, value UInt32) ENGINE = HDFS('hdfs://hdfs1:9000/{some,another}_dir/*', 'TSV')
+```
+
+:::warning    
+If the listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
+:::
+
+**Example**
+
+Create table with files named `file000`, `file001`, … , `file999`:
+
+``` sql
+CREATE TABLE big_table (name String, value UInt32) ENGINE = HDFS('hdfs://hdfs1:9000/big_dir/file{0..9}{0..9}{0..9}', 'CSV')
+```
+## Configuration {#configuration}
+
+Similar to GraphiteMergeTree, the HDFS engine supports extended configuration using the ClickHouse config file. There are two configuration keys that you can use: global (`hdfs`) and user-level (`hdfs_*`). The global configuration is applied first, and then the user-level configuration is applied (if it exists).
+
+``` xml
+  <!-- Global configuration options for HDFS engine type -->
+  <hdfs>
+	<hadoop_kerberos_keytab>/tmp/keytab/clickhouse.keytab</hadoop_kerberos_keytab>
+	<hadoop_kerberos_principal>clickuser@TEST.CLICKHOUSE.TECH</hadoop_kerberos_principal>
+	<hadoop_security_authentication>kerberos</hadoop_security_authentication>
+  </hdfs>
+
+  <!-- Configuration specific for user "root" -->
+  <hdfs_root>
+	<hadoop_kerberos_principal>root@TEST.CLICKHOUSE.TECH</hadoop_kerberos_principal>
+  </hdfs_root>
+```
+
+### Configuration Options {#configuration-options}
+
+#### Supported by libhdfs3 {#supported-by-libhdfs3}
+
+
+| **parameter**                                         | **default value**       |
+| -                                                     | -                       |
+| rpc\_client\_connect\_tcpnodelay                      | true                    |
+| dfs\_client\_read\_shortcircuit                       | true                    |
+| output\_replace-datanode-on-failure                   | true                    |
+| input\_notretry-another-node                          | false                   |
+| input\_localread\_mappedfile                          | true                    |
+| dfs\_client\_use\_legacy\_blockreader\_local          | false                   |
+| rpc\_client\_ping\_interval                           | 10  * 1000              |
+| rpc\_client\_connect\_timeout                         | 600 * 1000              |
+| rpc\_client\_read\_timeout                            | 3600 * 1000             |
+| rpc\_client\_write\_timeout                           | 3600 * 1000             |
+| rpc\_client\_socekt\_linger\_timeout                  | -1                      |
+| rpc\_client\_connect\_retry                           | 10                      |
+| rpc\_client\_timeout                                  | 3600 * 1000             |
+| dfs\_default\_replica                                 | 3                       |
+| input\_connect\_timeout                               | 600 * 1000              |
+| input\_read\_timeout                                  | 3600 * 1000             |
+| input\_write\_timeout                                 | 3600 * 1000             |
+| input\_localread\_default\_buffersize                 | 1 * 1024 * 1024         |
+| dfs\_prefetchsize                                     | 10                      |
+| input\_read\_getblockinfo\_retry                      | 3                       |
+| input\_localread\_blockinfo\_cachesize                | 1000                    |
+| input\_read\_max\_retry                               | 60                      |
+| output\_default\_chunksize                            | 512                     |
+| output\_default\_packetsize                           | 64 * 1024               |
+| output\_default\_write\_retry                         | 10                      |
+| output\_connect\_timeout                              | 600 * 1000              |
+| output\_read\_timeout                                 | 3600 * 1000             |
+| output\_write\_timeout                                | 3600 * 1000             |
+| output\_close\_timeout                                | 3600 * 1000             |
+| output\_packetpool\_size                              | 1024                    |
+| output\_heeartbeat\_interval                          | 10 * 1000               |
+| dfs\_client\_failover\_max\_attempts                  | 15                      |
+| dfs\_client\_read\_shortcircuit\_streams\_cache\_size | 256                     |
+| dfs\_client\_socketcache\_expiryMsec                  | 3000                    |
+| dfs\_client\_socketcache\_capacity                    | 16                      |
+| dfs\_default\_blocksize                               | 64 * 1024 * 1024        |
+| dfs\_default\_uri                                     | "hdfs://localhost:9000" |
+| hadoop\_security\_authentication                      | "simple"                |
+| hadoop\_security\_kerberos\_ticket\_cache\_path       | ""                      |
+| dfs\_client\_log\_severity                            | "INFO"                  |
+| dfs\_domain\_socket\_path                             | ""                      |
+
+
+[HDFS Configuration Reference](https://hawq.apache.org/docs/userguide/2.3.0.0-incubating/reference/HDFSConfigurationParameterReference.html) might explain some parameters.
+
+
+#### ClickHouse extras {#clickhouse-extras}
+
+| **parameter**                                         | **default value**       |
+| -                                                     | -                       |
+|hadoop\_kerberos\_keytab                               | ""                      |
+|hadoop\_kerberos\_principal                            | ""                      |
+|hadoop\_kerberos\_kinit\_command                       | kinit                   |
+|libhdfs3\_conf                                         | ""                      |
+
+### Limitations {#limitations}
+* `hadoop_security_kerberos_ticket_cache_path` and `libhdfs3_conf` can be global only, not user specific
+
+## Kerberos support {#kerberos-support}
+
+If the `hadoop_security_authentication` parameter has the value `kerberos`, ClickHouse authenticates via Kerberos.
+Parameters are [here](#clickhouse-extras) and `hadoop_security_kerberos_ticket_cache_path` may be of help.
+Note that due to libhdfs3 limitations only old-fashioned approach is supported,
+datanode communications are not secured by SASL (`HADOOP_SECURE_DN_USER` is a reliable indicator of such
+security approach). Use `tests/integration/test_storage_kerberized_hdfs/hdfs_configs/bootstrap.sh` for reference.
+
+If `hadoop_kerberos_keytab`, `hadoop_kerberos_principal` or `hadoop_kerberos_kinit_command` is specified, `kinit` will be invoked. `hadoop_kerberos_keytab` and `hadoop_kerberos_principal` are mandatory in this case. `kinit` tool and krb5 configuration files are required.
+
+## HDFS Namenode HA support {#namenode-ha}
+
+libhdfs3 support HDFS namenode HA.
+
+- Copy `hdfs-site.xml` from an HDFS node to `/etc/clickhouse-server/`.
+- Add following piece to ClickHouse config file:
+
+``` xml
+  <hdfs>
+    <libhdfs3_conf>/etc/clickhouse-server/hdfs-site.xml</libhdfs3_conf>
+  </hdfs>
+```
+
+- Then use `dfs.nameservices` tag value of `hdfs-site.xml` as the namenode address in the HDFS URI. For example, replace `hdfs://appadmin@192.168.101.11:8020/abc/` with `hdfs://appadmin@my_nameservice/abc/`.
+
+
+## Virtual Columns {#virtual-columns}
+
+-   `_path` — Path to the file.
+-   `_file` — Name of the file.
+
+**See Also**
+
+-   [Virtual columns](../../../engines/table-engines/index.md#table_engines-virtual_columns)
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/hdfs/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/hive.md b/docs/en/reference/engines/table-engines/integrations/hive.md
new file mode 100644
index 00000000000..6731f0e7559
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/hive.md
@@ -0,0 +1,410 @@
+---
+sidebar_position: 4
+sidebar_label: Hive
+---
+
+# Hive {#hive}
+
+The Hive engine allows you to perform `SELECT` quries on HDFS Hive table. Currently it supports input formats as below:
+
+- Text: only supports simple scalar column types except `binary` 
+
+- ORC: support simple scalar columns types except `char`; only support complex types like `array`
+
+- Parquet: support all simple scalar columns types; only support complex types like `array`
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [ALIAS expr1],
+    name2 [type2] [ALIAS expr2],
+    ...
+) ENGINE = Hive('thrift://host:port', 'database', 'table');
+PARTITION BY expr
+```
+See a detailed description of the [CREATE TABLE](../../../sql-reference/statements/create/table.md#create-table-query) query.
+
+The table structure can differ from the original Hive table structure:
+-   Column names should be the same as in the original Hive table, but you can use just some of these columns and in any order, also you can use some alias columns calculated from other columns.
+-   Column types should be the same from those in the original Hive table.
+-   Partition by expression should be consistent with the original Hive table, and columns in partition by expression should be in the table structure.
+
+**Engine Parameters**
+
+-   `thrift://host:port` — Hive Metastore address
+
+-   `database` — Remote database name.
+
+-   `table` — Remote table name.
+
+## Usage Example {#usage-example}
+
+### How to Use Local Cache for HDFS Filesystem
+We strongly advice you to enable local cache for remote filesystems. Benchmark shows that its almost 2x faster with cache.
+
+Before using cache, add it to `config.xml`
+``` xml
+<local_cache_for_remote_fs>
+    <enable>true</enable>
+    <root_dir>local_cache</root_dir>
+    <limit_size>559096952</limit_size>
+    <bytes_read_before_flush>1048576</bytes_read_before_flush>
+</local_cache_for_remote_fs>
+```
+
+- enable: ClickHouse will maintain local cache for remote filesystem(HDFS) after startup if true.
+- root_dir: Required. The root directory to store local cache files for remote filesystem.
+- limit_size: Required. The maximum size(in bytes) of local cache files.
+- bytes_read_before_flush: Control bytes before flush to local filesystem when downloading file from remote filesystem. The default value is 1MB.
+
+When ClickHouse is started up with local cache for remote filesystem enabled, users can still choose not to use cache with `settings use_local_cache_for_remote_fs = 0` in their query. `use_local_cache_for_remote_fs` is `false` in default.
+
+### Query Hive Table with ORC Input Format
+
+#### Create Table in Hive
+``` text
+hive > CREATE TABLE `test`.`test_orc`(
+  `f_tinyint` tinyint, 
+  `f_smallint` smallint, 
+  `f_int` int, 
+  `f_integer` int, 
+  `f_bigint` bigint, 
+  `f_float` float, 
+  `f_double` double, 
+  `f_decimal` decimal(10,0), 
+  `f_timestamp` timestamp, 
+  `f_date` date, 
+  `f_string` string, 
+  `f_varchar` varchar(100), 
+  `f_bool` boolean, 
+  `f_binary` binary, 
+  `f_array_int` array<int>, 
+  `f_array_string` array<string>, 
+  `f_array_float` array<float>, 
+  `f_array_array_int` array<array<int>>, 
+  `f_array_array_string` array<array<string>>, 
+  `f_array_array_float` array<array<float>>)
+PARTITIONED BY ( 
+  `day` string)
+ROW FORMAT SERDE 
+  'org.apache.hadoop.hive.ql.io.orc.OrcSerde' 
+STORED AS INPUTFORMAT 
+  'org.apache.hadoop.hive.ql.io.orc.OrcInputFormat' 
+OUTPUTFORMAT 
+  'org.apache.hadoop.hive.ql.io.orc.OrcOutputFormat'
+LOCATION
+  'hdfs://testcluster/data/hive/test.db/test_orc'
+
+OK
+Time taken: 0.51 seconds
+
+hive > insert into test.test_orc partition(day='2021-09-18') select 1, 2, 3, 4, 5, 6.11, 7.22, 8.333, current_timestamp(), current_date(), 'hello world', 'hello world', 'hello world', true, 'hello world', array(1, 2, 3), array('hello world', 'hello world'), array(float(1.1), float(1.2)), array(array(1, 2), array(3, 4)), array(array('a', 'b'), array('c', 'd')), array(array(float(1.11), float(2.22)), array(float(3.33), float(4.44)));
+OK
+Time taken: 36.025 seconds
+
+hive > select * from test.test_orc;
+OK
+1	2	3	4	5	6.11	7.22	8	2021-11-05 12:38:16.314	2021-11-05	hello world	hello world	hello world                                                                                         	true	hello world	[1,2,3]	["hello world","hello world"]	[1.1,1.2]	[[1,2],[3,4]]	[["a","b"],["c","d"]]	[[1.11,2.22],[3.33,4.44]]	2021-09-18
+Time taken: 0.295 seconds, Fetched: 1 row(s)
+```
+
+#### Create Table in ClickHouse
+Table in ClickHouse, retrieving data from the Hive table created above:
+``` sql
+CREATE TABLE test.test_orc
+(
+    `f_tinyint` Int8,
+    `f_smallint` Int16,
+    `f_int` Int32,
+    `f_integer` Int32,
+    `f_bigint` Int64,
+    `f_float` Float32,
+    `f_double` Float64,
+    `f_decimal` Float64,
+    `f_timestamp` DateTime,
+    `f_date` Date,
+    `f_string` String,
+    `f_varchar` String,
+    `f_bool` Bool,
+    `f_binary` String,
+    `f_array_int` Array(Int32),
+    `f_array_string` Array(String),
+    `f_array_float` Array(Float32),
+    `f_array_array_int` Array(Array(Int32)),
+    `f_array_array_string` Array(Array(String)),
+    `f_array_array_float` Array(Array(Float32)),
+    `day` String
+)
+ENGINE = Hive('thrift://202.168.117.26:9083', 'test', 'test_orc')
+PARTITION BY day
+
+```
+
+``` sql
+SELECT * FROM test.test_orc settings input_format_orc_allow_missing_columns = 1\G
+```
+
+``` text
+SELECT *
+FROM test.test_orc
+SETTINGS input_format_orc_allow_missing_columns = 1
+
+Query id: c3eaffdc-78ab-43cd-96a4-4acc5b480658
+
+Row 1:
+──────
+f_tinyint:            1
+f_smallint:           2
+f_int:                3
+f_integer:            4
+f_bigint:             5
+f_float:              6.11
+f_double:             7.22
+f_decimal:            8
+f_timestamp:          2021-12-04 04:00:44
+f_date:               2021-12-03
+f_string:             hello world
+f_varchar:            hello world
+f_bool:               true
+f_binary:             hello world
+f_array_int:          [1,2,3]
+f_array_string:       ['hello world','hello world']
+f_array_float:        [1.1,1.2]
+f_array_array_int:    [[1,2],[3,4]]
+f_array_array_string: [['a','b'],['c','d']]
+f_array_array_float:  [[1.11,2.22],[3.33,4.44]]
+day:                  2021-09-18
+
+
+1 rows in set. Elapsed: 0.078 sec. 
+```
+
+### Query Hive Table with Parquet Input Format
+
+#### Create Table in Hive
+``` text
+hive >
+CREATE TABLE `test`.`test_parquet`(
+  `f_tinyint` tinyint, 
+  `f_smallint` smallint, 
+  `f_int` int, 
+  `f_integer` int, 
+  `f_bigint` bigint, 
+  `f_float` float, 
+  `f_double` double, 
+  `f_decimal` decimal(10,0), 
+  `f_timestamp` timestamp, 
+  `f_date` date, 
+  `f_string` string, 
+  `f_varchar` varchar(100), 
+  `f_char` char(100), 
+  `f_bool` boolean, 
+  `f_binary` binary, 
+  `f_array_int` array<int>, 
+  `f_array_string` array<string>, 
+  `f_array_float` array<float>, 
+  `f_array_array_int` array<array<int>>, 
+  `f_array_array_string` array<array<string>>, 
+  `f_array_array_float` array<array<float>>)
+PARTITIONED BY ( 
+  `day` string)
+ROW FORMAT SERDE 
+  'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe' 
+STORED AS INPUTFORMAT 
+  'org.apache.hadoop.hive.ql.io.parquet.MapredParquetInputFormat' 
+OUTPUTFORMAT 
+  'org.apache.hadoop.hive.ql.io.parquet.MapredParquetOutputFormat'
+LOCATION
+  'hdfs://testcluster/data/hive/test.db/test_parquet'
+OK
+Time taken: 0.51 seconds
+
+hive >  insert into test.test_parquet partition(day='2021-09-18') select 1, 2, 3, 4, 5, 6.11, 7.22, 8.333, current_timestamp(), current_date(), 'hello world', 'hello world', 'hello world', true, 'hello world', array(1, 2, 3), array('hello world', 'hello world'), array(float(1.1), float(1.2)), array(array(1, 2), array(3, 4)), array(array('a', 'b'), array('c', 'd')), array(array(float(1.11), float(2.22)), array(float(3.33), float(4.44)));
+OK
+Time taken: 36.025 seconds
+
+hive > select * from test.test_parquet;
+OK
+1	2	3	4	5	6.11	7.22	8	2021-12-14 17:54:56.743	2021-12-14	hello world	hello world	hello world                                                                                         	true	hello world	[1,2,3]	["hello world","hello world"]	[1.1,1.2]	[[1,2],[3,4]]	[["a","b"],["c","d"]]	[[1.11,2.22],[3.33,4.44]]	2021-09-18
+Time taken: 0.766 seconds, Fetched: 1 row(s)
+```
+
+#### Create Table in ClickHouse
+Table in ClickHouse, retrieving data from the Hive table created above:
+``` sql
+CREATE TABLE test.test_parquet
+(
+    `f_tinyint` Int8,
+    `f_smallint` Int16,
+    `f_int` Int32,
+    `f_integer` Int32,
+    `f_bigint` Int64,
+    `f_float` Float32,
+    `f_double` Float64,
+    `f_decimal` Float64,
+    `f_timestamp` DateTime,
+    `f_date` Date,
+    `f_string` String,
+    `f_varchar` String,
+    `f_char` String,
+    `f_bool` Bool,
+    `f_binary` String,
+    `f_array_int` Array(Int32),
+    `f_array_string` Array(String),
+    `f_array_float` Array(Float32),
+    `f_array_array_int` Array(Array(Int32)),
+    `f_array_array_string` Array(Array(String)),
+    `f_array_array_float` Array(Array(Float32)),
+    `day` String
+)
+ENGINE = Hive('thrift://localhost:9083', 'test', 'test_parquet')
+PARTITION BY day
+```
+
+``` sql
+SELECT * FROM test.test_parquet settings input_format_parquet_allow_missing_columns = 1\G
+```
+
+``` text
+SELECT *
+FROM test_parquet
+SETTINGS input_format_parquet_allow_missing_columns = 1
+
+Query id: 4e35cf02-c7b2-430d-9b81-16f438e5fca9
+
+Row 1:
+──────
+f_tinyint:            1
+f_smallint:           2
+f_int:                3
+f_integer:            4
+f_bigint:             5
+f_float:              6.11
+f_double:             7.22
+f_decimal:            8
+f_timestamp:          2021-12-14 17:54:56
+f_date:               2021-12-14
+f_string:             hello world
+f_varchar:            hello world
+f_char:               hello world
+f_bool:               true
+f_binary:             hello world
+f_array_int:          [1,2,3]
+f_array_string:       ['hello world','hello world']
+f_array_float:        [1.1,1.2]
+f_array_array_int:    [[1,2],[3,4]]
+f_array_array_string: [['a','b'],['c','d']]
+f_array_array_float:  [[1.11,2.22],[3.33,4.44]]
+day:                  2021-09-18
+
+1 rows in set. Elapsed: 0.357 sec. 
+```
+
+### Query Hive Table with Text Input Format
+#### Create Table in Hive
+``` text
+hive >
+CREATE TABLE `test`.`test_text`(
+  `f_tinyint` tinyint, 
+  `f_smallint` smallint, 
+  `f_int` int, 
+  `f_integer` int, 
+  `f_bigint` bigint, 
+  `f_float` float, 
+  `f_double` double, 
+  `f_decimal` decimal(10,0), 
+  `f_timestamp` timestamp, 
+  `f_date` date, 
+  `f_string` string, 
+  `f_varchar` varchar(100), 
+  `f_char` char(100), 
+  `f_bool` boolean, 
+  `f_binary` binary, 
+  `f_array_int` array<int>, 
+  `f_array_string` array<string>, 
+  `f_array_float` array<float>, 
+  `f_array_array_int` array<array<int>>, 
+  `f_array_array_string` array<array<string>>, 
+  `f_array_array_float` array<array<float>>)
+PARTITIONED BY ( 
+  `day` string)
+ROW FORMAT SERDE 
+  'org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe' 
+STORED AS INPUTFORMAT 
+  'org.apache.hadoop.mapred.TextInputFormat' 
+OUTPUTFORMAT 
+  'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
+LOCATION
+  'hdfs://testcluster/data/hive/test.db/test_text'
+Time taken: 0.1 seconds, Fetched: 34 row(s)
+
+
+hive >  insert into test.test_text partition(day='2021-09-18') select 1, 2, 3, 4, 5, 6.11, 7.22, 8.333, current_timestamp(), current_date(), 'hello world', 'hello world', 'hello world', true, 'hello world', array(1, 2, 3), array('hello world', 'hello world'), array(float(1.1), float(1.2)), array(array(1, 2), array(3, 4)), array(array('a', 'b'), array('c', 'd')), array(array(float(1.11), float(2.22)), array(float(3.33), float(4.44)));
+OK
+Time taken: 36.025 seconds
+
+hive > select * from test.test_text;
+OK
+1	2	3	4	5	6.11	7.22	8	2021-12-14 18:11:17.239	2021-12-14	hello world	hello world	hello world                                                                                         	true	hello world	[1,2,3]	["hello world","hello world"]	[1.1,1.2]	[[1,2],[3,4]]	[["a","b"],["c","d"]]	[[1.11,2.22],[3.33,4.44]]	2021-09-18
+Time taken: 0.624 seconds, Fetched: 1 row(s)
+```
+
+#### Create Table in ClickHouse
+
+Table in ClickHouse, retrieving data from the Hive table created above:
+``` sql
+CREATE TABLE test.test_text
+(
+    `f_tinyint` Int8,
+    `f_smallint` Int16,
+    `f_int` Int32,
+    `f_integer` Int32,
+    `f_bigint` Int64,
+    `f_float` Float32,
+    `f_double` Float64,
+    `f_decimal` Float64,
+    `f_timestamp` DateTime,
+    `f_date` Date,
+    `f_string` String,
+    `f_varchar` String,
+    `f_char` String,
+    `f_bool` Bool,
+    `day` String
+)
+ENGINE = Hive('thrift://localhost:9083', 'test', 'test_text')
+PARTITION BY day 
+```
+
+``` sql
+SELECT * FROM test.test_text settings input_format_skip_unknown_fields = 1, input_format_with_names_use_header = 1, date_time_input_format = 'best_effort'\G
+```
+
+``` text
+SELECT *
+FROM test.test_text
+SETTINGS input_format_skip_unknown_fields = 1, input_format_with_names_use_header = 1, date_time_input_format = 'best_effort'
+
+Query id: 55b79d35-56de-45b9-8be6-57282fbf1f44
+
+Row 1:
+──────
+f_tinyint:   1
+f_smallint:  2
+f_int:       3
+f_integer:   4
+f_bigint:    5
+f_float:     6.11
+f_double:    7.22
+f_decimal:   8
+f_timestamp: 2021-12-14 18:11:17
+f_date:      2021-12-14
+f_string:    hello world
+f_varchar:   hello world
+f_char:      hello world
+f_bool:      true
+day:         2021-09-18
+```
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/hive/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/index.md b/docs/en/reference/engines/table-engines/integrations/index.md
new file mode 100644
index 00000000000..9230ad624ba
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/index.md
@@ -0,0 +1,23 @@
+---
+sidebar_position: 40
+sidebar_label:  Integrations
+---
+
+# Table Engines for Integrations {#table-engines-for-integrations}
+
+ClickHouse provides various means for integrating with external systems, including table engines. Like with all other table engines, the configuration is done using `CREATE TABLE` or `ALTER TABLE` queries. Then from a user perspective, the configured integration looks like a normal table, but queries to it are proxied to the external system. This transparent querying is one of the key advantages of this approach over alternative integration methods, like external dictionaries or table functions, which require to use custom query methods on each use.
+
+List of supported integrations:
+
+-   [ODBC](../../../engines/table-engines/integrations/odbc.md)
+-   [JDBC](../../../engines/table-engines/integrations/jdbc.md)
+-   [MySQL](../../../engines/table-engines/integrations/mysql.md)
+-   [MongoDB](../../../engines/table-engines/integrations/mongodb.md)
+-   [HDFS](../../../engines/table-engines/integrations/hdfs.md)
+-   [S3](../../../engines/table-engines/integrations/s3.md)
+-   [Kafka](../../../engines/table-engines/integrations/kafka.md)
+-   [EmbeddedRocksDB](../../../engines/table-engines/integrations/embedded-rocksdb.md)
+-   [RabbitMQ](../../../engines/table-engines/integrations/rabbitmq.md)
+-   [PostgreSQL](../../../engines/table-engines/integrations/postgresql.md)
+-   [SQLite](../../../engines/table-engines/integrations/sqlite.md)
+-   [Hive](../../../engines/table-engines/integrations/hive.md)
diff --git a/docs/en/reference/engines/table-engines/integrations/jdbc.md b/docs/en/reference/engines/table-engines/integrations/jdbc.md
new file mode 100644
index 00000000000..0ce31f36070
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/jdbc.md
@@ -0,0 +1,95 @@
+---
+sidebar_position: 3
+sidebar_label: JDBC
+---
+
+# JDBC {#table-engine-jdbc}
+
+Allows ClickHouse to connect to external databases via [JDBC](https://en.wikipedia.org/wiki/Java_Database_Connectivity).
+
+To implement the JDBC connection, ClickHouse uses the separate program [clickhouse-jdbc-bridge](https://github.com/ClickHouse/clickhouse-jdbc-bridge) that should run as a daemon.
+
+This engine supports the [Nullable](../../../sql-reference/data-types/nullable.md) data type.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name
+(
+    columns list...
+)
+ENGINE = JDBC(datasource_uri, external_database, external_table)
+```
+
+**Engine Parameters**
+
+
+-   `datasource_uri` — URI or name of an external DBMS.
+
+    URI Format: `jdbc:<driver_name>://<host_name>:<port>/?user=<username>&password=<password>`.
+    Example for MySQL: `jdbc:mysql://localhost:3306/?user=root&password=root`.
+
+-   `external_database` — Database in an external DBMS.
+
+-   `external_table` — Name of the table in `external_database` or a select query like `select * from table1 where column1=1`.
+
+## Usage Example {#usage-example}
+
+Creating a table in MySQL server by connecting directly with it’s console client:
+
+``` text
+mysql> CREATE TABLE `test`.`test` (
+    ->   `int_id` INT NOT NULL AUTO_INCREMENT,
+    ->   `int_nullable` INT NULL DEFAULT NULL,
+    ->   `float` FLOAT NOT NULL,
+    ->   `float_nullable` FLOAT NULL DEFAULT NULL,
+    ->   PRIMARY KEY (`int_id`));
+Query OK, 0 rows affected (0,09 sec)
+
+mysql> insert into test (`int_id`, `float`) VALUES (1,2);
+Query OK, 1 row affected (0,00 sec)
+
+mysql> select * from test;
++------+----------+-----+----------+
+| int_id | int_nullable | float | float_nullable |
++------+----------+-----+----------+
+|      1 |         NULL |     2 |           NULL |
++------+----------+-----+----------+
+1 row in set (0,00 sec)
+```
+
+Creating a table in ClickHouse server and selecting data from it:
+
+``` sql
+CREATE TABLE jdbc_table
+(
+    `int_id` Int32,
+    `int_nullable` Nullable(Int32),
+    `float` Float32,
+    `float_nullable` Nullable(Float32)
+)
+ENGINE JDBC('jdbc:mysql://localhost:3306/?user=root&password=root', 'test', 'test')
+```
+
+``` sql
+SELECT *
+FROM jdbc_table
+```
+
+``` text
+┌─int_id─┬─int_nullable─┬─float─┬─float_nullable─┐
+│      1 │         ᴺᵁᴸᴸ │     2 │           ᴺᵁᴸᴸ │
+└────────┴──────────────┴───────┴────────────────┘
+```
+
+``` sql
+INSERT INTO jdbc_table(`int_id`, `float`)
+SELECT toInt32(number), toFloat32(number * 1.0)
+FROM system.numbers
+```
+
+## See Also {#see-also}
+
+-   [JDBC table function](../../../sql-reference/table-functions/jdbc.md).
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/jdbc/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/kafka.md b/docs/en/reference/engines/table-engines/integrations/kafka.md
new file mode 100644
index 00000000000..3a8d98e1ca9
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/kafka.md
@@ -0,0 +1,198 @@
+---
+sidebar_position: 8
+sidebar_label: Kafka
+---
+
+# Kafka {#kafka}
+
+This engine works with [Apache Kafka](http://kafka.apache.org/).
+
+Kafka lets you:
+
+-   Publish or subscribe to data flows.
+-   Organize fault-tolerant storage.
+-   Process streams as they become available.
+
+## Creating a Table {#table_engine-kafka-creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = Kafka()
+SETTINGS
+    kafka_broker_list = 'host:port',
+    kafka_topic_list = 'topic1,topic2,...',
+    kafka_group_name = 'group_name',
+    kafka_format = 'data_format'[,]
+    [kafka_row_delimiter = 'delimiter_symbol',]
+    [kafka_schema = '',]
+    [kafka_num_consumers = N,]
+    [kafka_max_block_size = 0,]
+    [kafka_skip_broken_messages = N,]
+    [kafka_commit_every_batch = 0,]
+    [kafka_thread_per_consumer = 0]
+```
+
+Required parameters:
+
+-   `kafka_broker_list` — A comma-separated list of brokers (for example, `localhost:9092`).
+-   `kafka_topic_list` — A list of Kafka topics.
+-   `kafka_group_name` — A group of Kafka consumers. Reading margins are tracked for each group separately. If you do not want messages to be duplicated in the cluster, use the same group name everywhere.
+-   `kafka_format` — Message format. Uses the same notation as the SQL `FORMAT` function, such as `JSONEachRow`. For more information, see the [Formats](../../../interfaces/formats.md) section.
+
+Optional parameters:
+
+-   `kafka_row_delimiter` — Delimiter character, which ends the message.
+-   `kafka_schema` — Parameter that must be used if the format requires a schema definition. For example, [Cap’n Proto](https://capnproto.org/) requires the path to the schema file and the name of the root `schema.capnp:Message` object.
+-   `kafka_num_consumers` — The number of consumers per table. Default: `1`. Specify more consumers if the throughput of one consumer is insufficient. The total number of consumers should not exceed the number of partitions in the topic, since only one consumer can be assigned per partition.
+-   `kafka_max_block_size` — The maximum batch size (in messages) for poll (default: `max_block_size`).
+-   `kafka_skip_broken_messages` — Kafka message parser tolerance to schema-incompatible messages per block. Default: `0`. If `kafka_skip_broken_messages = N` then the engine skips *N* Kafka messages that cannot be parsed (a message equals a row of data).
+-   `kafka_commit_every_batch` — Commit every consumed and handled batch instead of a single commit after writing a whole block (default: `0`).
+-   `kafka_thread_per_consumer` — Provide independent thread for each consumer (default: `0`). When enabled, every consumer flush the data independently, in parallel (otherwise — rows from several consumers squashed to form one block).
+
+Examples:
+
+``` sql
+  CREATE TABLE queue (
+    timestamp UInt64,
+    level String,
+    message String
+  ) ENGINE = Kafka('localhost:9092', 'topic', 'group1', 'JSONEachRow');
+
+  SELECT * FROM queue LIMIT 5;
+
+  CREATE TABLE queue2 (
+    timestamp UInt64,
+    level String,
+    message String
+  ) ENGINE = Kafka SETTINGS kafka_broker_list = 'localhost:9092',
+                            kafka_topic_list = 'topic',
+                            kafka_group_name = 'group1',
+                            kafka_format = 'JSONEachRow',
+                            kafka_num_consumers = 4;
+
+  CREATE TABLE queue3 (
+    timestamp UInt64,
+    level String,
+    message String
+  ) ENGINE = Kafka('localhost:9092', 'topic', 'group1')
+              SETTINGS kafka_format = 'JSONEachRow',
+                       kafka_num_consumers = 4;
+```
+
+<details markdown="1">
+
+<summary>Deprecated Method for Creating a Table</summary>
+
+:::warning    
+Do not use this method in new projects. If possible, switch old projects to the method described above.
+:::
+
+``` sql
+Kafka(kafka_broker_list, kafka_topic_list, kafka_group_name, kafka_format
+      [, kafka_row_delimiter, kafka_schema, kafka_num_consumers, kafka_skip_broken_messages])
+```
+
+</details>
+
+## Description {#description}
+
+The delivered messages are tracked automatically, so each message in a group is only counted once. If you want to get the data twice, then create a copy of the table with another group name.
+
+Groups are flexible and synced on the cluster. For instance, if you have 10 topics and 5 copies of a table in a cluster, then each copy gets 2 topics. If the number of copies changes, the topics are redistributed across the copies automatically. Read more about this at http://kafka.apache.org/intro.
+
+`SELECT` is not particularly useful for reading messages (except for debugging), because each message can be read only once. It is more practical to create real-time threads using materialized views. To do this:
+
+1.  Use the engine to create a Kafka consumer and consider it a data stream.
+2.  Create a table with the desired structure.
+3.  Create a materialized view that converts data from the engine and puts it into a previously created table.
+
+When the `MATERIALIZED VIEW` joins the engine, it starts collecting data in the background. This allows you to continually receive messages from Kafka and convert them to the required format using `SELECT`.
+One kafka table can have as many materialized views as you like, they do not read data from the kafka table directly, but receive new records (in blocks), this way you can write to several tables with different detail level (with grouping - aggregation and without).
+
+Example:
+
+``` sql
+  CREATE TABLE queue (
+    timestamp UInt64,
+    level String,
+    message String
+  ) ENGINE = Kafka('localhost:9092', 'topic', 'group1', 'JSONEachRow');
+
+  CREATE TABLE daily (
+    day Date,
+    level String,
+    total UInt64
+  ) ENGINE = SummingMergeTree(day, (day, level), 8192);
+
+  CREATE MATERIALIZED VIEW consumer TO daily
+    AS SELECT toDate(toDateTime(timestamp)) AS day, level, count() as total
+    FROM queue GROUP BY day, level;
+
+  SELECT level, sum(total) FROM daily GROUP BY level;
+```
+To improve performance, received messages are grouped into blocks the size of [max_insert_block_size](../../../operations/settings/settings.md#settings-max_insert_block_size). If the block wasn’t formed within [stream_flush_interval_ms](../../../operations/settings/settings.md/#stream-flush-interval-ms) milliseconds, the data will be flushed to the table regardless of the completeness of the block.
+
+To stop receiving topic data or to change the conversion logic, detach the materialized view:
+
+``` sql
+  DETACH TABLE consumer;
+  ATTACH TABLE consumer;
+```
+
+If you want to change the target table by using `ALTER`, we recommend disabling the material view to avoid discrepancies between the target table and the data from the view.
+
+## Configuration {#configuration}
+
+Similar to GraphiteMergeTree, the Kafka engine supports extended configuration using the ClickHouse config file. There are two configuration keys that you can use: global (`kafka`) and topic-level (`kafka_*`). The global configuration is applied first, and then the topic-level configuration is applied (if it exists).
+
+``` xml
+  <!-- Global configuration options for all tables of Kafka engine type -->
+  <kafka>
+    <debug>cgrp</debug>
+    <auto_offset_reset>smallest</auto_offset_reset>
+  </kafka>
+
+  <!-- Configuration specific for topic "logs" -->
+  <kafka_logs>
+    <retry_backoff_ms>250</retry_backoff_ms>
+    <fetch_min_bytes>100000</fetch_min_bytes>
+  </kafka_logs>
+```
+
+For a list of possible configuration options, see the [librdkafka configuration reference](https://github.com/edenhill/librdkafka/blob/master/CONFIGURATION.md). Use the underscore (`_`) instead of a dot in the ClickHouse configuration. For example, `check.crcs=true` will be `<check_crcs>true</check_crcs>`.
+
+### Kerberos support {#kafka-kerberos-support}
+
+To deal with Kerberos-aware Kafka, add `security_protocol` child element with `sasl_plaintext` value. It is enough if Kerberos ticket-granting ticket is obtained and cached by OS facilities.
+ClickHouse is able to maintain Kerberos credentials using a keytab file. Consider `sasl_kerberos_service_name`, `sasl_kerberos_keytab`, `sasl_kerberos_principal` and `sasl.kerberos.kinit.cmd` child elements.
+
+Example:
+
+``` xml
+  <!-- Kerberos-aware Kafka -->
+  <kafka>
+    <security_protocol>SASL_PLAINTEXT</security_protocol>
+	<sasl_kerberos_keytab>/home/kafkauser/kafkauser.keytab</sasl_kerberos_keytab>
+	<sasl_kerberos_principal>kafkauser/kafkahost@EXAMPLE.COM</sasl_kerberos_principal>
+  </kafka>
+```
+
+## Virtual Columns {#virtual-columns}
+
+-   `_topic` — Kafka topic.
+-   `_key` — Key of the message.
+-   `_offset` — Offset of the message.
+-   `_timestamp` — Timestamp of the message.
+-   `_timestamp_ms` — Timestamp in milliseconds of the message.
+-   `_partition` — Partition of Kafka topic.
+
+**See Also**
+
+-   [Virtual columns](../../../engines/table-engines/index.md#table_engines-virtual_columns)
+-   [background_message_broker_schedule_pool_size](../../../operations/settings/settings.md#background_message_broker_schedule_pool_size)
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/kafka/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/materialized-postgresql.md b/docs/en/reference/engines/table-engines/integrations/materialized-postgresql.md
new file mode 100644
index 00000000000..61f97961ddb
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/materialized-postgresql.md
@@ -0,0 +1,59 @@
+---
+sidebar_position: 12
+sidebar_label: MaterializedPostgreSQL
+---
+
+# MaterializedPostgreSQL {#materialize-postgresql}
+
+Creates ClickHouse table with an initial data dump of PostgreSQL table and starts replication process, i.e. executes background job to apply new changes as they happen on PostgreSQL table in the remote PostgreSQL database.
+
+If more than one table is required, it is highly recommended to use the [MaterializedPostgreSQL](../../../engines/database-engines/materialized-postgresql.md) database engine instead of the table engine and use the `materialized_postgresql_tables_list` setting, which specifies the tables to be replicated (will also be possible to add database `schema`). It will be much better in terms of CPU, fewer connections and fewer replication slots inside the remote PostgreSQL database.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE postgresql_db.postgresql_replica (key UInt64, value UInt64)
+ENGINE = MaterializedPostgreSQL('postgres1:5432', 'postgres_database', 'postgresql_replica', 'postgres_user', 'postgres_password')
+PRIMARY KEY key;
+```
+
+**Engine Parameters**
+
+-   `host:port` — PostgreSQL server address.
+-   `database` — Remote database name.
+-   `table` — Remote table name.
+-   `user` — PostgreSQL user.
+-   `password` — User password.
+
+## Requirements {#requirements}
+
+1. The [wal_level](https://www.postgresql.org/docs/current/runtime-config-wal.html) setting must have a value `logical` and `max_replication_slots` parameter must have a value at least `2` in the PostgreSQL config file.
+
+2. A table with `MaterializedPostgreSQL` engine must have a primary key — the same as a replica identity index (by default: primary key) of a PostgreSQL table (see [details on replica identity index](../../../engines/database-engines/materialized-postgresql.md#requirements)).
+
+3. Only database [Atomic](https://en.wikipedia.org/wiki/Atomicity_(database_systems)) is allowed.
+
+## Virtual columns {#virtual-columns}
+
+-   `_version` — Transaction counter. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+-   `_sign` — Deletion mark. Type: [Int8](../../../sql-reference/data-types/int-uint.md). Possible values:
+    - `1` — Row is not deleted,
+    - `-1` — Row is deleted.
+
+These columns do not need to be added when a table is created. They are always accessible in `SELECT` query.
+`_version` column equals `LSN` position in `WAL`, so it might be used to check how up-to-date replication is.
+
+``` sql
+CREATE TABLE postgresql_db.postgresql_replica (key UInt64, value UInt64)
+ENGINE = MaterializedPostgreSQL('postgres1:5432', 'postgres_database', 'postgresql_replica', 'postgres_user', 'postgres_password')
+PRIMARY KEY key;
+
+SELECT key, value, _version FROM postgresql_db.postgresql_replica;
+```
+
+:::warning    
+Replication of [**TOAST**](https://www.postgresql.org/docs/9.5/storage-toast.html) values is not supported. The default value for the data type will be used.
+:::
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/materialized-postgresql) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/mongodb.md b/docs/en/reference/engines/table-engines/integrations/mongodb.md
new file mode 100644
index 00000000000..d212ab4720f
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/mongodb.md
@@ -0,0 +1,79 @@
+---
+sidebar_position: 5
+sidebar_label: MongoDB
+---
+
+# MongoDB {#mongodb}
+
+MongoDB engine is read-only table engine which allows to read data (`SELECT` queries) from remote MongoDB collection. Engine supports only non-nested data types. `INSERT` queries are not supported.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name
+(
+    name1 [type1],
+    name2 [type2],
+    ...
+) ENGINE = MongoDB(host:port, database, collection, user, password [, options]);
+```
+
+**Engine Parameters**
+
+-   `host:port` — MongoDB server address.
+
+-   `database` — Remote database name.
+
+-   `collection` — Remote collection name.
+
+-   `user` — MongoDB user.
+
+-   `password` — User password.
+
+-   `options` — MongoDB connection string options (optional parameter).
+
+## Usage Example {#usage-example}
+
+Create a table in ClickHouse which allows to read data from MongoDB collection:
+
+``` sql
+CREATE TABLE mongo_table
+(
+    key UInt64,
+    data String
+) ENGINE = MongoDB('mongo1:27017', 'test', 'simple_table', 'testuser', 'clickhouse');
+```
+
+To read from an SSL secured MongoDB server:
+
+``` sql
+CREATE TABLE mongo_table_ssl
+(
+    key UInt64,
+    data String
+) ENGINE = MongoDB('mongo2:27017', 'test', 'simple_table', 'testuser', 'clickhouse', 'ssl=true');
+```
+
+Query:
+
+``` sql
+SELECT COUNT() FROM mongo_table;
+```
+
+``` text
+┌─count()─┐
+│       4 │
+└─────────┘
+```
+
+You can also adjust connection timeout:
+
+``` sql
+CREATE TABLE mongo_table
+(
+    key UInt64,
+    data String
+) ENGINE = MongoDB('mongo2:27017', 'test', 'simple_table', 'testuser', 'clickhouse', 'connectTimeoutMS=100000');
+```
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/mongodb/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/mysql.md b/docs/en/reference/engines/table-engines/integrations/mysql.md
new file mode 100644
index 00000000000..e962db58873
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/mysql.md
@@ -0,0 +1,152 @@
+---
+sidebar_position: 4
+sidebar_label: MySQL
+---
+
+# MySQL {#mysql}
+
+The MySQL engine allows you to perform `SELECT` and `INSERT` queries on data that is stored on a remote MySQL server.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1] [TTL expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2] [TTL expr2],
+    ...
+) ENGINE = MySQL('host:port', 'database', 'table', 'user', 'password'[, replace_query, 'on_duplicate_clause'])
+SETTINGS
+    [connection_pool_size=16, ]
+    [connection_max_tries=3, ]
+    [connection_wait_timeout=5, ] /* 0 -- do not wait */
+    [connection_auto_close=true ]
+;
+```
+
+See a detailed description of the [CREATE TABLE](../../../sql-reference/statements/create/table.md#create-table-query) query.
+
+The table structure can differ from the original MySQL table structure:
+
+-   Column names should be the same as in the original MySQL table, but you can use just some of these columns and in any order.
+-   Column types may differ from those in the original MySQL table. ClickHouse tries to [cast](../../../engines/database-engines/mysql.md#data_types-support) values to the ClickHouse data types.
+-   The [external_table_functions_use_nulls](../../../operations/settings/settings.md#external-table-functions-use-nulls) setting defines how to handle Nullable columns. Default value: 1. If 0, the table function does not make Nullable columns and inserts default values instead of nulls. This is also applicable for NULL values inside arrays.
+
+**Engine Parameters**
+
+-   `host:port` — MySQL server address.
+
+-   `database` — Remote database name.
+
+-   `table` — Remote table name.
+
+-   `user` — MySQL user.
+
+-   `password` — User password.
+
+-   `replace_query` — Flag that converts `INSERT INTO` queries to `REPLACE INTO`. If `replace_query=1`, the query is substituted.
+
+-   `on_duplicate_clause` — The `ON DUPLICATE KEY on_duplicate_clause` expression that is added to the `INSERT` query.
+
+    Example: `INSERT INTO t (c1,c2) VALUES ('a', 2) ON DUPLICATE KEY UPDATE c2 = c2 + 1`, where `on_duplicate_clause` is `UPDATE c2 = c2 + 1`. See the [MySQL documentation](https://dev.mysql.com/doc/refman/8.0/en/insert-on-duplicate.html) to find which `on_duplicate_clause` you can use with the `ON DUPLICATE KEY` clause.
+
+    To specify `on_duplicate_clause` you need to pass `0` to the `replace_query` parameter. If you simultaneously pass `replace_query = 1` and `on_duplicate_clause`, ClickHouse generates an exception.
+
+Simple `WHERE` clauses such as `=, !=, >, >=, <, <=` are executed on the MySQL server.
+
+The rest of the conditions and the `LIMIT` sampling constraint are executed in ClickHouse only after the query to MySQL finishes.
+
+Supports multiple replicas that must be listed by `|`. For example:
+
+```sql
+CREATE TABLE test_replicas (id UInt32, name String, age UInt32, money UInt32) ENGINE = MySQL(`mysql{2|3|4}:3306`, 'clickhouse', 'test_replicas', 'root', 'clickhouse');
+```
+
+## Usage Example {#usage-example}
+
+Table in MySQL:
+
+``` text
+mysql> CREATE TABLE `test`.`test` (
+    ->   `int_id` INT NOT NULL AUTO_INCREMENT,
+    ->   `int_nullable` INT NULL DEFAULT NULL,
+    ->   `float` FLOAT NOT NULL,
+    ->   `float_nullable` FLOAT NULL DEFAULT NULL,
+    ->   PRIMARY KEY (`int_id`));
+Query OK, 0 rows affected (0,09 sec)
+
+mysql> insert into test (`int_id`, `float`) VALUES (1,2);
+Query OK, 1 row affected (0,00 sec)
+
+mysql> select * from test;
++------+----------+-----+----------+
+| int_id | int_nullable | float | float_nullable |
++------+----------+-----+----------+
+|      1 |         NULL |     2 |           NULL |
++------+----------+-----+----------+
+1 row in set (0,00 sec)
+```
+
+Table in ClickHouse, retrieving data from the MySQL table created above:
+
+``` sql
+CREATE TABLE mysql_table
+(
+    `float_nullable` Nullable(Float32),
+    `int_id` Int32
+)
+ENGINE = MySQL('localhost:3306', 'test', 'test', 'bayonet', '123')
+```
+
+``` sql
+SELECT * FROM mysql_table
+```
+
+``` text
+┌─float_nullable─┬─int_id─┐
+│           ᴺᵁᴸᴸ │      1 │
+└────────────────┴────────┘
+```
+
+## Settings {#mysql-settings}
+
+Default settings are not very efficient, since they do not even reuse connections. These settings allow you to increase the number of queries run by the server per second.
+
+### connection_auto_close {#connection-auto-close}
+
+Allows to automatically close the connection after query execution, i.e. disable connection reuse.
+
+Possible values:
+
+-   1 — Auto-close connection is allowed, so the connection reuse is disabled
+-   0 — Auto-close connection is not allowed, so the connection reuse is enabled
+
+Default value: `1`.
+
+### connection_max_tries {#connection-max-tries}
+
+Sets the number of retries for pool with failover.
+
+Possible values:
+
+-   Positive integer.
+-   0 — There are no retries for pool with failover.
+
+Default value: `3`.
+
+### connection_pool_size {#connection-pool-size}
+
+Size of connection pool (if all connections are in use, the query will wait until some connection will be freed).
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `16`.
+
+## See Also {#see-also}
+
+-   [The mysql table function](../../../sql-reference/table-functions/mysql.md)
+-   [Using MySQL as a source of external dictionary](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-mysql)
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/mysql/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/odbc.md b/docs/en/reference/engines/table-engines/integrations/odbc.md
new file mode 100644
index 00000000000..ed2b77d7ca3
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/odbc.md
@@ -0,0 +1,131 @@
+---
+sidebar_position: 2
+sidebar_label: ODBC
+---
+
+# ODBC {#table-engine-odbc}
+
+Allows ClickHouse to connect to external databases via [ODBC](https://en.wikipedia.org/wiki/Open_Database_Connectivity).
+
+To safely implement ODBC connections, ClickHouse uses a separate program `clickhouse-odbc-bridge`. If the ODBC driver is loaded directly from `clickhouse-server`, driver problems can crash the ClickHouse server. ClickHouse automatically starts `clickhouse-odbc-bridge` when it is required. The ODBC bridge program is installed from the same package as the `clickhouse-server`.
+
+This engine supports the [Nullable](../../../sql-reference/data-types/nullable.md) data type.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1],
+    name2 [type2],
+    ...
+)
+ENGINE = ODBC(connection_settings, external_database, external_table)
+```
+
+See a detailed description of the [CREATE TABLE](../../../sql-reference/statements/create/table.md#create-table-query) query.
+
+The table structure can differ from the source table structure:
+
+-   Column names should be the same as in the source table, but you can use just some of these columns and in any order.
+-   Column types may differ from those in the source table. ClickHouse tries to [cast](../../../sql-reference/functions/type-conversion-functions.md#type_conversion_function-cast) values to the ClickHouse data types.
+-   The [external_table_functions_use_nulls](../../../operations/settings/settings.md#external-table-functions-use-nulls) setting defines how to handle Nullable columns. Default value: 1. If 0, the table function does not make Nullable columns and inserts default values instead of nulls. This is also applicable for NULL values inside arrays.
+
+**Engine Parameters**
+
+-   `connection_settings` — Name of the section with connection settings in the `odbc.ini` file.
+-   `external_database` — Name of a database in an external DBMS.
+-   `external_table` — Name of a table in the `external_database`.
+
+## Usage Example {#usage-example}
+
+**Retrieving data from the local MySQL installation via ODBC**
+
+This example is checked for Ubuntu Linux 18.04 and MySQL server 5.7.
+
+Ensure that unixODBC and MySQL Connector are installed.
+
+By default (if installed from packages), ClickHouse starts as user `clickhouse`. Thus, you need to create and configure this user in the MySQL server.
+
+``` bash
+$ sudo mysql
+```
+
+``` sql
+mysql> CREATE USER 'clickhouse'@'localhost' IDENTIFIED BY 'clickhouse';
+mysql> GRANT ALL PRIVILEGES ON *.* TO 'clickhouse'@'clickhouse' WITH GRANT OPTION;
+```
+
+Then configure the connection in `/etc/odbc.ini`.
+
+``` bash
+$ cat /etc/odbc.ini
+[mysqlconn]
+DRIVER = /usr/local/lib/libmyodbc5w.so
+SERVER = 127.0.0.1
+PORT = 3306
+DATABASE = test
+USERNAME = clickhouse
+PASSWORD = clickhouse
+```
+
+You can check the connection using the `isql` utility from the unixODBC installation.
+
+``` bash
+$ isql -v mysqlconn
++-------------------------+
+| Connected!                            |
+|                                       |
+...
+```
+
+Table in MySQL:
+
+``` text
+mysql> CREATE TABLE `test`.`test` (
+    ->   `int_id` INT NOT NULL AUTO_INCREMENT,
+    ->   `int_nullable` INT NULL DEFAULT NULL,
+    ->   `float` FLOAT NOT NULL,
+    ->   `float_nullable` FLOAT NULL DEFAULT NULL,
+    ->   PRIMARY KEY (`int_id`));
+Query OK, 0 rows affected (0,09 sec)
+
+mysql> insert into test (`int_id`, `float`) VALUES (1,2);
+Query OK, 1 row affected (0,00 sec)
+
+mysql> select * from test;
++------+----------+-----+----------+
+| int_id | int_nullable | float | float_nullable |
++------+----------+-----+----------+
+|      1 |         NULL |     2 |           NULL |
++------+----------+-----+----------+
+1 row in set (0,00 sec)
+```
+
+Table in ClickHouse, retrieving data from the MySQL table:
+
+``` sql
+CREATE TABLE odbc_t
+(
+    `int_id` Int32,
+    `float_nullable` Nullable(Float32)
+)
+ENGINE = ODBC('DSN=mysqlconn', 'test', 'test')
+```
+
+``` sql
+SELECT * FROM odbc_t
+```
+
+``` text
+┌─int_id─┬─float_nullable─┐
+│      1 │           ᴺᵁᴸᴸ │
+└────────┴────────────────┘
+```
+
+## See Also {#see-also}
+
+-   [ODBC external dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-odbc)
+-   [ODBC table function](../../../sql-reference/table-functions/odbc.md)
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/odbc/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/postgresql.md b/docs/en/reference/engines/table-engines/integrations/postgresql.md
new file mode 100644
index 00000000000..d6826000a1a
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/postgresql.md
@@ -0,0 +1,178 @@
+---
+sidebar_position: 11
+sidebar_label: PostgreSQL
+---
+
+# PostgreSQL {#postgresql}
+
+The PostgreSQL engine allows to perform `SELECT` and `INSERT` queries on data that is stored on a remote PostgreSQL server.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1] [TTL expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2] [TTL expr2],
+    ...
+) ENGINE = PostgreSQL('host:port', 'database', 'table', 'user', 'password'[, `schema`]);
+```
+
+See a detailed description of the [CREATE TABLE](../../../sql-reference/statements/create/table.md#create-table-query) query.
+
+The table structure can differ from the original PostgreSQL table structure:
+
+-   Column names should be the same as in the original PostgreSQL table, but you can use just some of these columns and in any order.
+-   Column types may differ from those in the original PostgreSQL table. ClickHouse tries to [cast](../../../engines/database-engines/postgresql.md#data_types-support) values to the ClickHouse data types.
+-   The [external_table_functions_use_nulls](../../../operations/settings/settings.md#external-table-functions-use-nulls) setting defines how to handle Nullable columns. Default value: 1. If 0, the table function does not make Nullable columns and inserts default values instead of nulls. This is also applicable for NULL values inside arrays.
+
+**Engine Parameters**
+
+-   `host:port` — PostgreSQL server address.
+-   `database` — Remote database name.
+-   `table` — Remote table name.
+-   `user` — PostgreSQL user.
+-   `password` — User password.
+-   `schema` — Non-default table schema. Optional.
+-   `on conflict ...` — example: `ON CONFLICT DO NOTHING`. Optional. Note: adding this option will make insertion less efficient.
+
+or via config (since version 21.11):
+
+```
+<named_collections>
+    <postgres1>
+        <host></host>
+        <port></port>
+        <username></username>
+        <password></password>
+        <table></table>
+    </postgres1>
+    <postgres2>
+        <host></host>
+        <port></port>
+        <username></username>
+        <password></password>
+    </postgres2>
+</named_collections>
+```
+
+Some parameters can be overriden by key value arguments:
+``` sql
+SELECT * FROM postgresql(postgres1, schema='schema1', table='table1');
+```
+
+## Implementation Details {#implementation-details}
+
+`SELECT` queries on PostgreSQL side run as `COPY (SELECT ...) TO STDOUT` inside read-only PostgreSQL transaction with commit after each `SELECT` query.
+
+Simple `WHERE` clauses such as `=`, `!=`, `>`, `>=`, `<`, `<=`, and `IN` are executed on the PostgreSQL server.
+
+All joins, aggregations, sorting, `IN [ array ]` conditions and the `LIMIT` sampling constraint are executed in ClickHouse only after the query to PostgreSQL finishes.
+
+`INSERT` queries on PostgreSQL side run as `COPY "table_name" (field1, field2, ... fieldN) FROM STDIN` inside PostgreSQL transaction with auto-commit after each `INSERT` statement.
+
+PostgreSQL `Array` types are converted into ClickHouse arrays.
+
+:::warning    
+Be careful - in PostgreSQL an array data, created like a `type_name[]`, may contain multi-dimensional arrays of different dimensions in different table rows in same column. But in ClickHouse it is only allowed to have multidimensional arrays of the same count of dimensions in all table rows in same column.
+:::
+
+Supports multiple replicas that must be listed by `|`. For example:
+
+```sql
+CREATE TABLE test_replicas (id UInt32, name String) ENGINE = PostgreSQL(`postgres{2|3|4}:5432`, 'clickhouse', 'test_replicas', 'postgres', 'mysecretpassword');
+```
+
+Replicas priority for PostgreSQL dictionary source is supported. The bigger the number in map, the less the priority. The highest priority is `0`.
+
+In the example below replica `example01-1` has the highest priority:
+
+```xml
+<postgresql>
+    <port>5432</port>
+    <user>clickhouse</user>
+    <password>qwerty</password>
+    <replica>
+        <host>example01-1</host>
+        <priority>1</priority>
+    </replica>
+    <replica>
+        <host>example01-2</host>
+        <priority>2</priority>
+    </replica>
+    <db>db_name</db>
+    <table>table_name</table>
+    <where>id=10</where>
+    <invalidate_query>SQL_QUERY</invalidate_query>
+</postgresql>
+</source>
+```
+
+## Usage Example {#usage-example}
+
+Table in PostgreSQL:
+
+``` text
+postgres=# CREATE TABLE "public"."test" (
+"int_id" SERIAL,
+"int_nullable" INT NULL DEFAULT NULL,
+"float" FLOAT NOT NULL,
+"str" VARCHAR(100) NOT NULL DEFAULT '',
+"float_nullable" FLOAT NULL DEFAULT NULL,
+PRIMARY KEY (int_id));
+
+CREATE TABLE
+
+postgres=# INSERT INTO test (int_id, str, "float") VALUES (1,'test',2);
+INSERT 0 1
+
+postgresql> SELECT * FROM test;
+  int_id | int_nullable | float | str  | float_nullable
+ --------+--------------+-------+------+----------------
+       1 |              |     2 | test |
+ (1 row)
+```
+
+Table in ClickHouse, retrieving data from the PostgreSQL table created above:
+
+``` sql
+CREATE TABLE default.postgresql_table
+(
+    `float_nullable` Nullable(Float32),
+    `str` String,
+    `int_id` Int32
+)
+ENGINE = PostgreSQL('localhost:5432', 'public', 'test', 'postges_user', 'postgres_password');
+```
+
+``` sql
+SELECT * FROM postgresql_table WHERE str IN ('test');
+```
+
+``` text
+┌─float_nullable─┬─str──┬─int_id─┐
+│           ᴺᵁᴸᴸ │ test │      1 │
+└────────────────┴──────┴────────┘
+```
+
+Using Non-default Schema:
+
+```text
+postgres=# CREATE SCHEMA "nice.schema";
+
+postgres=# CREATE TABLE "nice.schema"."nice.table" (a integer);
+
+postgres=# INSERT INTO "nice.schema"."nice.table" SELECT i FROM generate_series(0, 99) as t(i)
+```
+
+```sql
+CREATE TABLE pg_table_schema_with_dots (a UInt32)
+        ENGINE PostgreSQL('localhost:5432', 'clickhouse', 'nice.table', 'postgrsql_user', 'password', 'nice.schema');
+```
+
+**See Also**
+
+-   [The `postgresql` table function](../../../sql-reference/table-functions/postgresql.md)
+-   [Using PostgreSQL as a source of external dictionary](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-postgresql)
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/postgresql/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/rabbitmq.md b/docs/en/reference/engines/table-engines/integrations/rabbitmq.md
new file mode 100644
index 00000000000..6653b76594a
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/integrations/rabbitmq.md
@@ -0,0 +1,175 @@
+---
+sidebar_position: 10
+sidebar_label: RabbitMQ
+---
+
+# RabbitMQ Engine {#rabbitmq-engine}
+
+This engine allows integrating ClickHouse with [RabbitMQ](https://www.rabbitmq.com).
+
+`RabbitMQ` lets you:
+
+-   Publish or subscribe to data flows.
+-   Process streams as they become available.
+
+## Creating a Table {#table_engine-rabbitmq-creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = RabbitMQ SETTINGS
+    rabbitmq_host_port = 'host:port' [or rabbitmq_address = 'amqp(s)://guest:guest@localhost/vhost'],
+    rabbitmq_exchange_name = 'exchange_name',
+    rabbitmq_format = 'data_format'[,]
+    [rabbitmq_exchange_type = 'exchange_type',]
+    [rabbitmq_routing_key_list = 'key1,key2,...',]
+    [rabbitmq_secure = 0,]
+    [rabbitmq_row_delimiter = 'delimiter_symbol',]
+    [rabbitmq_schema = '',]
+    [rabbitmq_num_consumers = N,]
+    [rabbitmq_num_queues = N,]
+    [rabbitmq_queue_base = 'queue',]
+    [rabbitmq_deadletter_exchange = 'dl-exchange',]
+    [rabbitmq_persistent = 0,]
+    [rabbitmq_skip_broken_messages = N,]
+    [rabbitmq_max_block_size = N,]
+    [rabbitmq_flush_interval_ms = N]
+    [rabbitmq_queue_settings_list = 'x-dead-letter-exchange=my-dlx,x-max-length=10,x-overflow=reject-publish']
+```
+
+Required parameters:
+
+-   `rabbitmq_host_port` – host:port (for example, `localhost:5672`).
+-   `rabbitmq_exchange_name` – RabbitMQ exchange name.
+-   `rabbitmq_format` – Message format. Uses the same notation as the SQL `FORMAT` function, such as `JSONEachRow`. For more information, see the [Formats](../../../interfaces/formats.md) section.
+
+Optional parameters:
+
+-   `rabbitmq_exchange_type` – The type of RabbitMQ exchange: `direct`, `fanout`, `topic`, `headers`, `consistent_hash`. Default: `fanout`.
+-   `rabbitmq_routing_key_list` – A comma-separated list of routing keys.
+-   `rabbitmq_row_delimiter` – Delimiter character, which ends the message.
+-   `rabbitmq_schema` – Parameter that must be used if the format requires a schema definition. For example, [Cap’n Proto](https://capnproto.org/) requires the path to the schema file and the name of the root `schema.capnp:Message` object.
+-   `rabbitmq_num_consumers` – The number of consumers per table. Default: `1`. Specify more consumers if the throughput of one consumer is insufficient.
+-   `rabbitmq_num_queues` – Total number of queues. Default: `1`. Increasing this number can significantly improve performance.
+-   `rabbitmq_queue_base` - Specify a hint for queue names. Use cases of this setting are described below.
+-   `rabbitmq_deadletter_exchange` - Specify name for a [dead letter exchange](https://www.rabbitmq.com/dlx.html). You can create another table with this exchange name and collect messages in cases when they are republished to dead letter exchange. By default dead letter exchange is not specified.
+-   `rabbitmq_persistent` - If set to 1 (true), in insert query delivery mode will be set to 2 (marks messages as 'persistent'). Default: `0`.
+-   `rabbitmq_skip_broken_messages` – RabbitMQ message parser tolerance to schema-incompatible messages per block. Default: `0`. If `rabbitmq_skip_broken_messages = N` then the engine skips *N* RabbitMQ messages that cannot be parsed (a message equals a row of data).
+-   `rabbitmq_max_block_size`
+-   `rabbitmq_flush_interval_ms`
+-   `rabbitmq_queue_settings_list` - allows to set RabbitMQ settings when creating a queue. Available settings: `x-max-length`, `x-max-length-bytes`, `x-message-ttl`, `x-expires`, `x-priority`, `x-max-priority`, `x-overflow`, `x-dead-letter-exchange`, `x-queue-type`. The `durable` setting is enabled automatically for the queue.
+
+SSL connection:
+
+Use either `rabbitmq_secure = 1` or `amqps` in connection address: `rabbitmq_address = 'amqps://guest:guest@localhost/vhost'`.
+The default behaviour of the used library is not to check if the created TLS connection is sufficiently secure. Whether the certificate is expired, self-signed, missing or invalid: the connection is simply permitted. More strict checking of certificates can possibly be implemented in the future.
+
+Also format settings can be added along with rabbitmq-related settings.
+
+Example:
+
+``` sql
+  CREATE TABLE queue (
+    key UInt64,
+    value UInt64,
+    date DateTime
+  ) ENGINE = RabbitMQ SETTINGS rabbitmq_host_port = 'localhost:5672',
+                            rabbitmq_exchange_name = 'exchange1',
+                            rabbitmq_format = 'JSONEachRow',
+                            rabbitmq_num_consumers = 5,
+                            date_time_input_format = 'best_effort';
+```
+
+The RabbitMQ server configuration should be added using the ClickHouse config file.
+
+Required configuration:
+
+``` xml
+ <rabbitmq>
+    <username>root</username>
+    <password>clickhouse</password>
+ </rabbitmq>
+```
+
+Additional configuration:
+
+``` xml
+ <rabbitmq>
+    <vhost>clickhouse</vhost>
+ </rabbitmq>
+```
+
+## Description {#description}
+
+`SELECT` is not particularly useful for reading messages (except for debugging), because each message can be read only once. It is more practical to create real-time threads using [materialized views](../../../sql-reference/statements/create/view.md). To do this:
+
+1.  Use the engine to create a RabbitMQ consumer and consider it a data stream.
+2.  Create a table with the desired structure.
+3.  Create a materialized view that converts data from the engine and puts it into a previously created table.
+
+When the `MATERIALIZED VIEW` joins the engine, it starts collecting data in the background. This allows you to continually receive messages from RabbitMQ and convert them to the required format using `SELECT`.
+One RabbitMQ table can have as many materialized views as you like.
+
+Data can be channeled based on `rabbitmq_exchange_type` and the specified `rabbitmq_routing_key_list`.
+There can be no more than one exchange per table. One exchange can be shared between multiple tables - it enables routing into multiple tables at the same time.
+
+Exchange type options:
+
+-   `direct` - Routing is based on the exact matching of keys. Example table key list: `key1,key2,key3,key4,key5`, message key can equal any of them.
+-   `fanout` - Routing to all tables (where exchange name is the same) regardless of the keys.
+-   `topic` - Routing is based on patterns with dot-separated keys. Examples: `*.logs`, `records.*.*.2020`, `*.2018,*.2019,*.2020`.
+-   `headers` - Routing is based on `key=value` matches with a setting `x-match=all` or `x-match=any`. Example table key list: `x-match=all,format=logs,type=report,year=2020`.
+-   `consistent_hash` - Data is evenly distributed between all bound tables (where the exchange name is the same). Note that this exchange type must be enabled with RabbitMQ plugin: `rabbitmq-plugins enable rabbitmq_consistent_hash_exchange`.
+
+Setting `rabbitmq_queue_base` may be used for the following cases:
+
+-   to let different tables share queues, so that multiple consumers could be registered for the same queues, which makes a better performance. If using `rabbitmq_num_consumers` and/or `rabbitmq_num_queues` settings, the exact match of queues is achieved in case these parameters are the same.
+-   to be able to restore reading from certain durable queues when not all messages were successfully consumed. To resume consumption from one specific queue - set its name in `rabbitmq_queue_base` setting and do not specify `rabbitmq_num_consumers` and `rabbitmq_num_queues` (defaults to 1). To resume consumption from all queues, which were declared for a specific table - just specify the same settings: `rabbitmq_queue_base`, `rabbitmq_num_consumers`, `rabbitmq_num_queues`. By default, queue names will be unique to tables.
+-   to reuse queues as they are declared durable and not auto-deleted. (Can be deleted via any of RabbitMQ CLI tools.)
+
+To improve performance, received messages are grouped into blocks the size of [max_insert_block_size](../../../operations/server-configuration-parameters/settings.md#settings-max_insert_block_size). If the block wasn’t formed within [stream_flush_interval_ms](../../../operations/server-configuration-parameters/settings.md) milliseconds, the data will be flushed to the table regardless of the completeness of the block.
+
+If `rabbitmq_num_consumers` and/or `rabbitmq_num_queues` settings are specified along with `rabbitmq_exchange_type`, then:
+
+-   `rabbitmq-consistent-hash-exchange` plugin must be enabled.
+-   `message_id` property of the published messages must be specified (unique for each message/batch).
+
+For insert query there is message metadata, which is added for each published message: `messageID` and `republished` flag (true, if published more than once) - can be accessed via message headers.
+
+Do not use the same table for inserts and materialized views.
+
+Example:
+
+``` sql
+  CREATE TABLE queue (
+    key UInt64,
+    value UInt64
+  ) ENGINE = RabbitMQ SETTINGS rabbitmq_host_port = 'localhost:5672',
+                            rabbitmq_exchange_name = 'exchange1',
+                            rabbitmq_exchange_type = 'headers',
+                            rabbitmq_routing_key_list = 'format=logs,type=report,year=2020',
+                            rabbitmq_format = 'JSONEachRow',
+                            rabbitmq_num_consumers = 5;
+
+  CREATE TABLE daily (key UInt64, value UInt64)
+    ENGINE = MergeTree() ORDER BY key;
+
+  CREATE MATERIALIZED VIEW consumer TO daily
+    AS SELECT key, value FROM queue;
+
+  SELECT key, value FROM daily ORDER BY key;
+```
+
+## Virtual Columns {#virtual-columns}
+
+-   `_exchange_name` - RabbitMQ exchange name.
+-   `_channel_id` - ChannelID, on which consumer, who received the message, was declared.
+-   `_delivery_tag` - DeliveryTag of the received message. Scoped per channel.
+-   `_redelivered` - `redelivered` flag of the message.
+-   `_message_id` - messageID of the received message; non-empty if was set, when message was published.
+-   `_timestamp` - timestamp of the received message; non-empty if was set, when message was published.
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/rabbitmq/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/s3.md b/docs/en/reference/engines/table-engines/integrations/s3.md
new file mode 100644
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+++ b/docs/en/reference/engines/table-engines/integrations/s3.md
@@ -0,0 +1,163 @@
+---
+sidebar_position: 7
+sidebar_label: S3
+---
+
+# S3 Table Engine {#table-engine-s3}
+
+This engine provides integration with [Amazon S3](https://aws.amazon.com/s3/) ecosystem. This engine is similar to the [HDFS](../../../engines/table-engines/special/file.md#table_engines-hdfs) engine, but provides S3-specific features.
+
+## Create Table {#creating-a-table}
+
+``` sql
+CREATE TABLE s3_engine_table (name String, value UInt32)
+    ENGINE = S3(path, [aws_access_key_id, aws_secret_access_key,] format, [compression])
+    [SETTINGS ...]
+```
+
+**Engine parameters**
+
+-   `path` — Bucket url with path to file. Supports following wildcards in readonly mode: `*`, `?`, `{abc,def}` and `{N..M}` where `N`, `M` — numbers, `'abc'`, `'def'` — strings. For more information see [below](#wildcards-in-path).
+-   `format` — The [format](../../../interfaces/formats.md#formats) of the file.
+-   `aws_access_key_id`, `aws_secret_access_key` - Long-term credentials for the [AWS](https://aws.amazon.com/) account user.  You can use these to authenticate your requests. Parameter is optional. If credentials are not specified, they are used from the configuration file. For more information see [Using S3 for Data Storage](../mergetree-family/mergetree.md#table_engine-mergetree-s3).
+-   `compression` — Compression type. Supported values: `none`, `gzip/gz`, `brotli/br`, `xz/LZMA`, `zstd/zst`. Parameter is optional. By default, it will autodetect compression by file extension.
+
+**Example**
+
+``` sql
+CREATE TABLE s3_engine_table (name String, value UInt32) 
+    ENGINE=S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/test-data.csv.gz', 'CSV', 'gzip')
+    SETTINGS input_format_with_names_use_header = 0;
+
+INSERT INTO s3_engine_table VALUES ('one', 1), ('two', 2), ('three', 3);
+
+SELECT * FROM s3_engine_table LIMIT 2;
+```
+
+```text
+┌─name─┬─value─┐
+│ one  │     1 │
+│ two  │     2 │
+└──────┴───────┘
+```
+## Virtual columns {#virtual-columns}
+
+-   `_path` — Path to the file.
+-   `_file` — Name of the file.
+
+For more information about virtual columns see [here](../../../engines/table-engines/index.md#table_engines-virtual_columns).
+
+## Implementation Details {#implementation-details}
+
+-   Reads and writes can be parallel
+-   [Zero-copy](../../../operations/storing-data.md#zero-copy) replication is supported.  
+-   Not supported:
+    -   `ALTER` and `SELECT...SAMPLE` operations.
+    -   Indexes.
+
+## Wildcards In Path {#wildcards-in-path}
+
+`path` argument can specify multiple files using bash-like wildcards. For being processed file should exist and match to the whole path pattern. Listing of files is determined during `SELECT` (not at `CREATE` moment).
+
+-   `*` — Substitutes any number of any characters except `/` including empty string.
+-   `?` — Substitutes any single character.
+-   `{some_string,another_string,yet_another_one}` — Substitutes any of strings `'some_string', 'another_string', 'yet_another_one'`.
+-   `{N..M}` — Substitutes any number in range from N to M including both borders. N and M can have leading zeroes e.g. `000..078`.
+
+Constructions with `{}` are similar to the [remote](../../../sql-reference/table-functions/remote.md) table function.
+
+:::warning    
+If the listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
+:::
+
+**Example with wildcards 1**
+
+Create table with files named `file-000.csv`, `file-001.csv`, … , `file-999.csv`:
+
+``` sql
+CREATE TABLE big_table (name String, value UInt32)
+    ENGINE = S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/my_folder/file-{000..999}.csv', 'CSV');
+```
+
+**Example with wildcards 2**
+
+Suppose we have several files in CSV format with the following URIs on S3:
+
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/some_folder/some_file_1.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/some_folder/some_file_2.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/some_folder/some_file_3.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/another_folder/some_file_1.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/another_folder/some_file_2.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/another_folder/some_file_3.csv'
+
+
+There are several ways to make a table consisting of all six files:
+
+1. Specify the range of file postfixes:
+
+``` sql
+CREATE TABLE table_with_range (name String, value UInt32)
+    ENGINE = S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/{some,another}_folder/some_file_{1..3}', 'CSV');
+```
+
+2. Take all files with `some_file_` prefix (there should be no extra files with such prefix in both folders):
+
+``` sql
+CREATE TABLE table_with_question_mark (name String, value UInt32)
+    ENGINE = S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/{some,another}_folder/some_file_?', 'CSV');
+```
+
+3. Take all the files in both folders (all files should satisfy format and schema described in query):
+
+``` sql
+CREATE TABLE table_with_asterisk (name String, value UInt32)
+    ENGINE = S3('https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/{some,another}_folder/*', 'CSV');
+```
+
+## S3-related Settings {#settings}
+
+The following settings can be set before query execution or placed into configuration file.
+
+-   `s3_max_single_part_upload_size` — The maximum size of object to upload using singlepart upload to S3. Default value is `64Mb`.
+-   `s3_min_upload_part_size` — The minimum size of part to upload during multipart upload to [S3 Multipart upload](https://docs.aws.amazon.com/AmazonS3/latest/dev/uploadobjusingmpu.html). Default value is `512Mb`.
+-   `s3_max_redirects` — Max number of S3 redirects hops allowed. Default value is `10`.
+-   `s3_single_read_retries` — The maximum number of attempts during single read. Default value is `4`.
+
+Security consideration: if malicious user can specify arbitrary S3 URLs, `s3_max_redirects` must be set to zero to avoid [SSRF](https://en.wikipedia.org/wiki/Server-side_request_forgery) attacks; or alternatively, `remote_host_filter` must be specified in server configuration.
+
+## Endpoint-based Settings {#endpoint-settings}
+
+The following settings can be specified in configuration file for given endpoint (which will be matched by exact prefix of a URL):
+
+-   `endpoint` — Specifies prefix of an endpoint. Mandatory.
+-   `access_key_id` and `secret_access_key` — Specifies credentials to use with given endpoint. Optional.
+-   `use_environment_credentials` — If set to `true`, S3 client will try to obtain credentials from environment variables and [Amazon EC2](https://en.wikipedia.org/wiki/Amazon_Elastic_Compute_Cloud) metadata for given endpoint. Optional, default value is `false`.
+-   `region` — Specifies S3 region name. Optional.
+-   `use_insecure_imds_request` — If set to `true`, S3 client will use insecure IMDS request while obtaining credentials from Amazon EC2 metadata. Optional, default value is `false`.
+-   `header` —  Adds specified HTTP header to a request to given endpoint. Optional, can be speficied multiple times.
+-   `server_side_encryption_customer_key_base64` — If specified, required headers for accessing S3 objects with SSE-C encryption will be set. Optional.
+-   `max_single_read_retries` — The maximum number of attempts during single read. Default value is `4`. Optional.
+
+**Example:**
+
+``` xml
+<s3>
+    <endpoint-name>
+        <endpoint>https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/</endpoint>
+        <!-- <access_key_id>ACCESS_KEY_ID</access_key_id> -->
+        <!-- <secret_access_key>SECRET_ACCESS_KEY</secret_access_key> -->
+        <!-- <region>us-west-1</region> -->
+        <!-- <use_environment_credentials>false</use_environment_credentials> -->
+        <!-- <use_insecure_imds_request>false</use_insecure_imds_request> -->
+        <!-- <header>Authorization: Bearer SOME-TOKEN</header> -->
+        <!-- <server_side_encryption_customer_key_base64>BASE64-ENCODED-KEY</server_side_encryption_customer_key_base64> -->
+        <!-- <max_single_read_retries>4</max_single_read_retries> -->
+    </endpoint-name>
+</s3>
+```
+
+## See also
+
+-  [s3 table function](../../../sql-reference/table-functions/s3.md)
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/s3/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/integrations/sqlite.md b/docs/en/reference/engines/table-engines/integrations/sqlite.md
new file mode 100644
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@@ -0,0 +1,62 @@
+---
+sidebar_position: 7
+sidebar_label: SQLite
+---
+
+# SQLite {#sqlite}
+
+The engine allows to import and export data to SQLite and supports queries to SQLite tables directly from ClickHouse.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+    CREATE TABLE [IF NOT EXISTS] [db.]table_name 
+    (
+        name1 [type1], 
+        name2 [type2], ...
+    ) ENGINE = SQLite('db_path', 'table')
+```
+
+**Engine Parameters**
+
+-   `db_path` — Path to SQLite file with a database.
+-   `table` — Name of a table in the SQLite database.
+
+## Usage Example {#usage-example}
+
+Shows a query creating the SQLite table:
+
+```sql
+SHOW CREATE TABLE sqlite_db.table2;
+```
+
+``` text
+CREATE TABLE SQLite.table2
+( 
+    `col1` Nullable(Int32), 
+    `col2` Nullable(String)
+) 
+ENGINE = SQLite('sqlite.db','table2');
+```
+
+Returns the data from the table:
+
+``` sql
+SELECT * FROM sqlite_db.table2 ORDER BY col1;
+```
+
+```text
+┌─col1─┬─col2──┐
+│    1 │ text1 │
+│    2 │ text2 │
+│    3 │ text3 │
+└──────┴───────┘
+```
+
+**See Also**
+
+-   [SQLite](../../../engines/database-engines/sqlite.md) engine
+-   [sqlite](../../../sql-reference/table-functions/sqlite.md) table function
+
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/sqlite/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/log-family/index.md b/docs/en/reference/engines/table-engines/log-family/index.md
new file mode 100644
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@@ -0,0 +1,46 @@
+---
+sidebar_position: 20
+sidebar_label:  Log Family
+---
+
+# Log Engine Family {#log-engine-family}
+
+These engines were developed for scenarios when you need to quickly write many small tables (up to about 1 million rows) and read them later as a whole.
+
+Engines of the family:
+
+-   [StripeLog](../../../engines/table-engines/log-family/stripelog.md)
+-   [Log](../../../engines/table-engines/log-family/log.md)
+-   [TinyLog](../../../engines/table-engines/log-family/tinylog.md)
+
+`Log` family table engines can store data to [HDFS](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-hdfs) or [S3](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-s3) distributed file systems.
+
+## Common Properties {#common-properties}
+
+Engines:
+
+-   Store data on a disk.
+
+-   Append data to the end of file when writing.
+
+-   Support locks for concurrent data access.
+
+    During `INSERT` queries, the table is locked, and other queries for reading and writing data both wait for the table to unlock. If there are no data writing queries, any number of data reading queries can be performed concurrently.
+
+-   Do not support [mutations](../../../sql-reference/statements/alter/index.md#alter-mutations).
+
+-   Do not support indexes.
+
+    This means that `SELECT` queries for ranges of data are not efficient.
+
+-   Do not write data atomically.
+
+    You can get a table with corrupted data if something breaks the write operation, for example, abnormal server shutdown.
+
+## Differences {#differences}
+
+The `TinyLog` engine is the simplest in the family and provides the poorest functionality and lowest efficiency. The `TinyLog` engine does not support parallel data reading by several threads in a single query. It reads data slower than other engines in the family that support parallel reading from a single query and it uses almost as many file descriptors as the `Log` engine because it stores each column in a separate file. Use it only in simple scenarios.
+
+The `Log` and `StripeLog` engines support parallel data reading. When reading data, ClickHouse uses multiple threads. Each thread processes a separate data block. The `Log` engine uses a separate file for each column of the table. `StripeLog` stores all the data in one file. As a result, the `StripeLog` engine uses fewer file descriptors, but the `Log` engine provides higher efficiency when reading data.
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/log_family/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/log-family/log.md b/docs/en/reference/engines/table-engines/log-family/log.md
new file mode 100644
index 00000000000..8858699f045
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/log-family/log.md
@@ -0,0 +1,15 @@
+---
+toc_priority: 33
+toc_title: Log
+---
+
+# Log {#log}
+
+The engine belongs to the family of `Log` engines. See the common properties of `Log` engines and their differences in the [Log Engine Family](../../../engines/table-engines/log-family/index.md) article.
+
+`Log` differs from [TinyLog](../../../engines/table-engines/log-family/tinylog.md) in that a small file of "marks" resides with the column files. These marks are written on every data block and contain offsets that indicate where to start reading the file in order to skip the specified number of rows. This makes it possible to read table data in multiple threads.
+For concurrent data access, the read operations can be performed simultaneously, while write operations block reads and each other.
+The `Log` engine does not support indexes. Similarly, if writing to a table failed, the table is broken, and reading from it returns an error. The `Log` engine is appropriate for temporary data, write-once tables, and for testing or demonstration purposes.
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/log-family/log/) <!--hide-->
+
diff --git a/docs/en/reference/engines/table-engines/log-family/stripelog.md b/docs/en/reference/engines/table-engines/log-family/stripelog.md
new file mode 100644
index 00000000000..62703245062
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/log-family/stripelog.md
@@ -0,0 +1,93 @@
+---
+toc_priority: 32
+toc_title: StripeLog
+---
+
+# Stripelog {#stripelog}
+
+This engine belongs to the family of log engines. See the common properties of log engines and their differences in the [Log Engine Family](../../../engines/table-engines/log-family/index.md) article.
+
+Use this engine in scenarios when you need to write many tables with a small amount of data (less than 1 million rows).
+
+## Creating a Table {#table_engines-stripelog-creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    column1_name [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    column2_name [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = StripeLog
+```
+
+See the detailed description of the [CREATE TABLE](../../../sql-reference/statements/create/table.md#create-table-query) query.
+
+## Writing the Data {#table_engines-stripelog-writing-the-data}
+
+The `StripeLog` engine stores all the columns in one file. For each `INSERT` query, ClickHouse appends the data block to the end of a table file, writing columns one by one.
+
+For each table ClickHouse writes the files:
+
+-   `data.bin` — Data file.
+-   `index.mrk` — File with marks. Marks contain offsets for each column of each data block inserted.
+
+The `StripeLog` engine does not support the `ALTER UPDATE` and `ALTER DELETE` operations.
+
+## Reading the Data {#table_engines-stripelog-reading-the-data}
+
+The file with marks allows ClickHouse to parallelize the reading of data. This means that a `SELECT` query returns rows in an unpredictable order. Use the `ORDER BY` clause to sort rows.
+
+## Example of Use {#table_engines-stripelog-example-of-use}
+
+Creating a table:
+
+``` sql
+CREATE TABLE stripe_log_table
+(
+    timestamp DateTime,
+    message_type String,
+    message String
+)
+ENGINE = StripeLog
+```
+
+Inserting data:
+
+``` sql
+INSERT INTO stripe_log_table VALUES (now(),'REGULAR','The first regular message')
+INSERT INTO stripe_log_table VALUES (now(),'REGULAR','The second regular message'),(now(),'WARNING','The first warning message')
+```
+
+We used two `INSERT` queries to create two data blocks inside the `data.bin` file.
+
+ClickHouse uses multiple threads when selecting data. Each thread reads a separate data block and returns resulting rows independently as it finishes. As a result, the order of blocks of rows in the output does not match the order of the same blocks in the input in most cases. For example:
+
+``` sql
+SELECT * FROM stripe_log_table
+```
+
+``` text
+┌───────────timestamp─┬─message_type─┬─message────────────────────┐
+│ 2019-01-18 14:27:32 │ REGULAR      │ The second regular message │
+│ 2019-01-18 14:34:53 │ WARNING      │ The first warning message  │
+└─────────────────────┴──────────────┴────────────────────────────┘
+┌───────────timestamp─┬─message_type─┬─message───────────────────┐
+│ 2019-01-18 14:23:43 │ REGULAR      │ The first regular message │
+└─────────────────────┴──────────────┴───────────────────────────┘
+```
+
+Sorting the results (ascending order by default):
+
+``` sql
+SELECT * FROM stripe_log_table ORDER BY timestamp
+```
+
+``` text
+┌───────────timestamp─┬─message_type─┬─message────────────────────┐
+│ 2019-01-18 14:23:43 │ REGULAR      │ The first regular message  │
+│ 2019-01-18 14:27:32 │ REGULAR      │ The second regular message │
+│ 2019-01-18 14:34:53 │ WARNING      │ The first warning message  │
+└─────────────────────┴──────────────┴────────────────────────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/stripelog/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/log-family/tinylog.md b/docs/en/reference/engines/table-engines/log-family/tinylog.md
new file mode 100644
index 00000000000..2407355a857
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/log-family/tinylog.md
@@ -0,0 +1,14 @@
+---
+toc_priority: 34
+toc_title: TinyLog
+---
+
+# TinyLog {#tinylog}
+
+The engine belongs to the log engine family. See [Log Engine Family](../../../engines/table-engines/log-family/index.md) for common properties of log engines and their differences.
+
+This table engine is typically used with the write-once method: write data one time, then read it as many times as necessary. For example, you can use `TinyLog`-type tables for intermediary data that is processed in small batches. Note that storing data in a large number of small tables is inefficient.
+
+Queries are executed in a single stream. In other words, this engine is intended for relatively small tables (up to about 1,000,000 rows). It makes sense to use this table engine if you have many small tables, since it’s simpler than the [Log](../../../engines/table-engines/log-family/log.md) engine (fewer files need to be opened).
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/tinylog/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/aggregatingmergetree.md b/docs/en/reference/engines/table-engines/mergetree-family/aggregatingmergetree.md
new file mode 100644
index 00000000000..7be10cec2f5
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/mergetree-family/aggregatingmergetree.md
@@ -0,0 +1,104 @@
+---
+sidebar_position: 60
+sidebar_label:  AggregatingMergeTree
+---
+
+# AggregatingMergeTree {#aggregatingmergetree}
+
+The engine inherits from [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md#table_engines-mergetree), altering the logic for data parts merging. ClickHouse replaces all rows with the same primary key (or more accurately, with the same [sorting key](../../../engines/table-engines/mergetree-family/mergetree.md)) with a single row (within a one data part) that stores a combination of states of aggregate functions.
+
+You can use `AggregatingMergeTree` tables for incremental data aggregation, including for aggregated materialized views.
+
+The engine processes all columns with the following types:
+
+-   [AggregateFunction](../../../sql-reference/data-types/aggregatefunction.md)
+-   [SimpleAggregateFunction](../../../sql-reference/data-types/simpleaggregatefunction.md)
+
+It is appropriate to use `AggregatingMergeTree` if it reduces the number of rows by orders.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = AggregatingMergeTree()
+[PARTITION BY expr]
+[ORDER BY expr]
+[SAMPLE BY expr]
+[TTL expr]
+[SETTINGS name=value, ...]
+```
+
+For a description of request parameters, see [request description](../../../sql-reference/statements/create/table.md).
+
+**Query clauses**
+
+When creating a `AggregatingMergeTree` table the same [clauses](../../../engines/table-engines/mergetree-family/mergetree.md) are required, as when creating a `MergeTree` table.
+
+<details markdown="1">
+
+<summary>Deprecated Method for Creating a Table</summary>
+
+:::warning
+Do not use this method in new projects and, if possible, switch the old projects to the method described above.
+:::
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE [=] AggregatingMergeTree(date-column [, sampling_expression], (primary, key), index_granularity)
+```
+
+All of the parameters have the same meaning as in `MergeTree`.
+</details>
+
+## SELECT and INSERT {#select-and-insert}
+
+To insert data, use [INSERT SELECT](../../../sql-reference/statements/insert-into.md) query with aggregate -State- functions.
+When selecting data from `AggregatingMergeTree` table, use `GROUP BY` clause and the same aggregate functions as when inserting data, but using `-Merge` suffix.
+
+In the results of `SELECT` query, the values of `AggregateFunction` type have implementation-specific binary representation for all of the ClickHouse output formats. If dump data into, for example, `TabSeparated` format with `SELECT` query then this dump can be loaded back using `INSERT` query.
+
+## Example of an Aggregated Materialized View {#example-of-an-aggregated-materialized-view}
+
+`AggregatingMergeTree` materialized view that watches the `test.visits` table:
+
+``` sql
+CREATE MATERIALIZED VIEW test.basic
+ENGINE = AggregatingMergeTree() PARTITION BY toYYYYMM(StartDate) ORDER BY (CounterID, StartDate)
+AS SELECT
+    CounterID,
+    StartDate,
+    sumState(Sign)    AS Visits,
+    uniqState(UserID) AS Users
+FROM test.visits
+GROUP BY CounterID, StartDate;
+```
+
+Inserting data into the `test.visits` table.
+
+``` sql
+INSERT INTO test.visits ...
+```
+
+The data are inserted in both the table and view `test.basic` that will perform the aggregation.
+
+To get the aggregated data, we need to execute a query such as `SELECT ... GROUP BY ...` from the view `test.basic`:
+
+``` sql
+SELECT
+    StartDate,
+    sumMerge(Visits) AS Visits,
+    uniqMerge(Users) AS Users
+FROM test.basic
+GROUP BY StartDate
+ORDER BY StartDate;
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/aggregatingmergetree/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/collapsingmergetree.md b/docs/en/reference/engines/table-engines/mergetree-family/collapsingmergetree.md
new file mode 100644
index 00000000000..22863611e79
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/mergetree-family/collapsingmergetree.md
@@ -0,0 +1,307 @@
+---
+sidebar_position: 70
+sidebar_label: CollapsingMergeTree
+---
+
+# CollapsingMergeTree {#table_engine-collapsingmergetree}
+
+The engine inherits from [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md) and adds the logic of rows collapsing to data parts merge algorithm.
+
+`CollapsingMergeTree` asynchronously deletes (collapses) pairs of rows if all of the fields in a sorting key (`ORDER BY`) are equivalent excepting the particular field `Sign` which can have `1` and `-1` values. Rows without a pair are kept. For more details see the [Collapsing](#table_engine-collapsingmergetree-collapsing) section of the document.
+
+The engine may significantly reduce the volume of storage and increase the efficiency of `SELECT` query as a consequence.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = CollapsingMergeTree(sign)
+[PARTITION BY expr]
+[ORDER BY expr]
+[SAMPLE BY expr]
+[SETTINGS name=value, ...]
+```
+
+For a description of query parameters, see [query description](../../../sql-reference/statements/create/table.md).
+
+**CollapsingMergeTree Parameters**
+
+-   `sign` — Name of the column with the type of row: `1` is a “state” row, `-1` is a “cancel” row.
+
+    Column data type — `Int8`.
+
+**Query clauses**
+
+When creating a `CollapsingMergeTree` table, the same [query clauses](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table) are required, as when creating a `MergeTree` table.
+
+<details markdown="1">
+
+<summary>Deprecated Method for Creating a Table</summary>
+
+:::warning    
+Do not use this method in new projects and, if possible, switch old projects to the method described above.
+:::
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE [=] CollapsingMergeTree(date-column [, sampling_expression], (primary, key), index_granularity, sign)
+```
+
+All of the parameters excepting `sign` have the same meaning as in `MergeTree`.
+
+-   `sign` — Name of the column with the type of row: `1` — “state” row, `-1` — “cancel” row.
+
+    Column Data Type — `Int8`.
+
+</details>
+
+## Collapsing {#table_engine-collapsingmergetree-collapsing}
+
+### Data {#data}
+
+Consider the situation where you need to save continually changing data for some object. It sounds logical to have one row for an object and update it at any change, but update operation is expensive and slow for DBMS because it requires rewriting of the data in the storage. If you need to write data quickly, update not acceptable, but you can write the changes of an object sequentially as follows.
+
+Use the particular column `Sign`. If `Sign = 1` it means that the row is a state of an object, let’s call it “state” row. If `Sign = -1` it means the cancellation of the state of an object with the same attributes, let’s call it “cancel” row.
+
+For example, we want to calculate how much pages users checked at some site and how long they were there. At some moment we write the following row with the state of user activity:
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         5 │      146 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+At some moment later we register the change of user activity and write it with the following two rows.
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         5 │      146 │   -1 │
+│ 4324182021466249494 │         6 │      185 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+The first row cancels the previous state of the object (user). It should copy the sorting key fields of the cancelled state excepting `Sign`.
+
+The second row contains the current state.
+
+As we need only the last state of user activity, the rows
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         5 │      146 │    1 │
+│ 4324182021466249494 │         5 │      146 │   -1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+can be deleted collapsing the invalid (old) state of an object. `CollapsingMergeTree` does this while merging of the data parts.
+
+Why we need 2 rows for each change read in the [Algorithm](#table_engine-collapsingmergetree-collapsing-algorithm) paragraph.
+
+**Peculiar properties of such approach**
+
+1.  The program that writes the data should remember the state of an object to be able to cancel it. “Cancel” string should contain copies of the sorting key fields of the “state” string and the opposite `Sign`. It increases the initial size of storage but allows to write the data quickly.
+2.  Long growing arrays in columns reduce the efficiency of the engine due to load for writing. The more straightforward data, the higher the efficiency.
+3.  The `SELECT` results depend strongly on the consistency of object changes history. Be accurate when preparing data for inserting. You can get unpredictable results in inconsistent data, for example, negative values for non-negative metrics such as session depth.
+
+### Algorithm {#table_engine-collapsingmergetree-collapsing-algorithm}
+
+When ClickHouse merges data parts, each group of consecutive rows with the same sorting key (`ORDER BY`) is reduced to not more than two rows, one with `Sign = 1` (“state” row) and another with `Sign = -1` (“cancel” row). In other words, entries collapse.
+
+For each resulting data part ClickHouse saves:
+
+1.  The first “cancel” and the last “state” rows, if the number of “state” and “cancel” rows matches and the last row is a “state” row.
+2.  The last “state” row, if there are more “state” rows than “cancel” rows.
+3.  The first “cancel” row, if there are more “cancel” rows than “state” rows.
+4.  None of the rows, in all other cases.
+
+Also when there are at least 2 more “state” rows than “cancel” rows, or at least 2 more “cancel” rows then “state” rows, the merge continues, but ClickHouse treats this situation as a logical error and records it in the server log. This error can occur if the same data were inserted more than once.
+
+Thus, collapsing should not change the results of calculating statistics.
+Changes gradually collapsed so that in the end only the last state of almost every object left.
+
+The `Sign` is required because the merging algorithm does not guarantee that all of the rows with the same sorting key will be in the same resulting data part and even on the same physical server. ClickHouse process `SELECT` queries with multiple threads, and it can not predict the order of rows in the result. The aggregation is required if there is a need to get completely “collapsed” data from `CollapsingMergeTree` table.
+
+To finalize collapsing, write a query with `GROUP BY` clause and aggregate functions that account for the sign. For example, to calculate quantity, use `sum(Sign)` instead of `count()`. To calculate the sum of something, use `sum(Sign * x)` instead of `sum(x)`, and so on, and also add `HAVING sum(Sign) > 0`.
+
+The aggregates `count`, `sum` and `avg` could be calculated this way. The aggregate `uniq` could be calculated if an object has at least one state not collapsed. The aggregates `min` and `max` could not be calculated because `CollapsingMergeTree` does not save the values history of the collapsed states.
+
+If you need to extract data without aggregation (for example, to check whether rows are present whose newest values match certain conditions), you can use the `FINAL` modifier for the `FROM` clause. This approach is significantly less efficient.
+
+## Example of Use {#example-of-use}
+
+Example data:
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         5 │      146 │    1 │
+│ 4324182021466249494 │         5 │      146 │   -1 │
+│ 4324182021466249494 │         6 │      185 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+Creation of the table:
+
+``` sql
+CREATE TABLE UAct
+(
+    UserID UInt64,
+    PageViews UInt8,
+    Duration UInt8,
+    Sign Int8
+)
+ENGINE = CollapsingMergeTree(Sign)
+ORDER BY UserID
+```
+
+Insertion of the data:
+
+``` sql
+INSERT INTO UAct VALUES (4324182021466249494, 5, 146, 1)
+```
+
+``` sql
+INSERT INTO UAct VALUES (4324182021466249494, 5, 146, -1),(4324182021466249494, 6, 185, 1)
+```
+
+We use two `INSERT` queries to create two different data parts. If we insert the data with one query ClickHouse creates one data part and will not perform any merge ever.
+
+Getting the data:
+
+``` sql
+SELECT * FROM UAct
+```
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         5 │      146 │   -1 │
+│ 4324182021466249494 │         6 │      185 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         5 │      146 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+What do we see and where is collapsing?
+
+With two `INSERT` queries, we created 2 data parts. The `SELECT` query was performed in 2 threads, and we got a random order of rows. Collapsing not occurred because there was no merge of the data parts yet. ClickHouse merges data part in an unknown moment which we can not predict.
+
+Thus we need aggregation:
+
+``` sql
+SELECT
+    UserID,
+    sum(PageViews * Sign) AS PageViews,
+    sum(Duration * Sign) AS Duration
+FROM UAct
+GROUP BY UserID
+HAVING sum(Sign) > 0
+```
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┐
+│ 4324182021466249494 │         6 │      185 │
+└─────────────────────┴───────────┴──────────┘
+```
+
+If we do not need aggregation and want to force collapsing, we can use `FINAL` modifier for `FROM` clause.
+
+``` sql
+SELECT * FROM UAct FINAL
+```
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         6 │      185 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+This way of selecting the data is very inefficient. Don’t use it for big tables.
+
+## Example of Another Approach {#example-of-another-approach}
+
+Example data:
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         5 │      146 │    1 │
+│ 4324182021466249494 │        -5 │     -146 │   -1 │
+│ 4324182021466249494 │         6 │      185 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+The idea is that merges take into account only key fields. And in the “Cancel” line we can specify negative values that equalize the previous version of the row when summing without using the Sign column. For this approach, it is necessary to change the data type `PageViews`,`Duration` to store negative values of UInt8 -\> Int16.
+
+``` sql
+CREATE TABLE UAct
+(
+    UserID UInt64,
+    PageViews Int16,
+    Duration Int16,
+    Sign Int8
+)
+ENGINE = CollapsingMergeTree(Sign)
+ORDER BY UserID
+```
+
+Let’s test the approach:
+
+``` sql
+insert into UAct values(4324182021466249494,  5,  146,  1);
+insert into UAct values(4324182021466249494, -5, -146, -1);
+insert into UAct values(4324182021466249494,  6,  185,  1);
+
+select * from UAct final; // avoid using final in production (just for a test or small tables)
+```
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         6 │      185 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+``` sql
+SELECT
+    UserID,
+    sum(PageViews) AS PageViews,
+    sum(Duration) AS Duration
+FROM UAct
+GROUP BY UserID
+```
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┐
+│ 4324182021466249494 │         6 │      185 │
+└─────────────────────┴───────────┴──────────┘
+```
+
+``` sql
+select count() FROM UAct
+```
+
+``` text
+┌─count()─┐
+│       3 │
+└─────────┘
+```
+
+``` sql
+optimize table UAct final;
+
+select * FROM UAct
+```
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         6 │      185 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/collapsingmergetree/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/custom-partitioning-key.md b/docs/en/reference/engines/table-engines/mergetree-family/custom-partitioning-key.md
new file mode 100644
index 00000000000..716528f8d77
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/mergetree-family/custom-partitioning-key.md
@@ -0,0 +1,136 @@
+---
+sidebar_position: 30
+sidebar_label: Custom Partitioning Key
+---
+
+# Custom Partitioning Key {#custom-partitioning-key}
+
+:::warning   
+In most cases you do not need a partition key, and in most other cases you do not need a partition key more granular than by months. Partitioning does not speed up queries (in contrast to the ORDER BY expression). 
+
+You should never use too granular of partitioning. Don't partition your data by client identifiers or names. Instead, make a client identifier or name the first column in the ORDER BY expression.
+:::
+
+Partitioning is available for the [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md) family tables (including [replicated](../../../engines/table-engines/mergetree-family/replication.md) tables). [Materialized views](../../../engines/table-engines/special/materializedview.md#materializedview) based on MergeTree tables support partitioning, as well.
+
+A partition is a logical combination of records in a table by a specified criterion. You can set a partition by an arbitrary criterion, such as by month, by day, or by event type. Each partition is stored separately to simplify manipulations of this data. When accessing the data, ClickHouse uses the smallest subset of partitions possible.
+
+The partition is specified in the `PARTITION BY expr` clause when [creating a table](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table). The partition key can be any expression from the table columns. For example, to specify partitioning by month, use the expression `toYYYYMM(date_column)`:
+
+``` sql
+CREATE TABLE visits
+(
+    VisitDate Date,
+    Hour UInt8,
+    ClientID UUID
+)
+ENGINE = MergeTree()
+PARTITION BY toYYYYMM(VisitDate)
+ORDER BY Hour;
+```
+
+The partition key can also be a tuple of expressions (similar to the [primary key](../../../engines/table-engines/mergetree-family/mergetree.md#primary-keys-and-indexes-in-queries)). For example:
+
+``` sql
+ENGINE = ReplicatedCollapsingMergeTree('/clickhouse/tables/name', 'replica1', Sign)
+PARTITION BY (toMonday(StartDate), EventType)
+ORDER BY (CounterID, StartDate, intHash32(UserID));
+```
+
+In this example, we set partitioning by the event types that occurred during the current week.
+
+By default, the floating-point partition key is not supported. To use it enable the setting [allow_floating_point_partition_key](../../../operations/settings/merge-tree-settings.md#allow_floating_point_partition_key).
+
+When inserting new data to a table, this data is stored as a separate part (chunk) sorted by the primary key. In 10-15 minutes after inserting, the parts of the same partition are merged into the entire part.
+
+:::info    
+A merge only works for data parts that have the same value for the partitioning expression. This means **you shouldn’t make overly granular partitions** (more than about a thousand partitions). Otherwise, the `SELECT` query performs poorly because of an unreasonably large number of files in the file system and open file descriptors.
+:::
+
+Use the [system.parts](../../../operations/system-tables/parts.md#system_tables-parts) table to view the table parts and partitions. For example, let’s assume that we have a `visits` table with partitioning by month. Let’s perform the `SELECT` query for the `system.parts` table:
+
+``` sql
+SELECT
+    partition,
+    name,
+    active
+FROM system.parts
+WHERE table = 'visits'
+```
+
+``` text
+┌─partition─┬─name──────────────┬─active─┐
+│ 201901    │ 201901_1_3_1      │      0 │
+│ 201901    │ 201901_1_9_2_11   │      1 │
+│ 201901    │ 201901_8_8_0      │      0 │
+│ 201901    │ 201901_9_9_0      │      0 │
+│ 201902    │ 201902_4_6_1_11   │      1 │
+│ 201902    │ 201902_10_10_0_11 │      1 │
+│ 201902    │ 201902_11_11_0_11 │      1 │
+└───────────┴───────────────────┴────────┘
+```
+
+The `partition` column contains the names of the partitions. There are two partitions in this example: `201901` and `201902`. You can use this column value to specify the partition name in [ALTER … PARTITION](../../../sql-reference/statements/alter/partition.md) queries.
+
+The `name` column contains the names of the partition data parts. You can use this column to specify the name of the part in the [ALTER ATTACH PART](../../../sql-reference/statements/alter/partition.md#alter_attach-partition) query.
+
+Let’s break down the name of the part: `201901_1_9_2_11`:
+
+-   `201901` is the partition name.
+-   `1` is the minimum number of the data block.
+-   `9` is the maximum number of the data block.
+-   `2` is the chunk level (the depth of the merge tree it is formed from).
+-   `11` is the mutation version (if a part mutated)
+
+:::info
+The parts of old-type tables have the name: `20190117_20190123_2_2_0` (minimum date - maximum date - minimum block number - maximum block number - level).
+:::
+
+The `active` column shows the status of the part. `1` is active; `0` is inactive. The inactive parts are, for example, source parts remaining after merging to a larger part. The corrupted data parts are also indicated as inactive.
+
+As you can see in the example, there are several separated parts of the same partition (for example, `201901_1_3_1` and `201901_1_9_2`). This means that these parts are not merged yet. ClickHouse merges the inserted parts of data periodically, approximately 15 minutes after inserting. In addition, you can perform a non-scheduled merge using the [OPTIMIZE](../../../sql-reference/statements/optimize.md) query. Example:
+
+``` sql
+OPTIMIZE TABLE visits PARTITION 201902;
+```
+
+``` text
+┌─partition─┬─name─────────────┬─active─┐
+│ 201901    │ 201901_1_3_1     │      0 │
+│ 201901    │ 201901_1_9_2_11  │      1 │
+│ 201901    │ 201901_8_8_0     │      0 │
+│ 201901    │ 201901_9_9_0     │      0 │
+│ 201902    │ 201902_4_6_1     │      0 │
+│ 201902    │ 201902_4_11_2_11 │      1 │
+│ 201902    │ 201902_10_10_0   │      0 │
+│ 201902    │ 201902_11_11_0   │      0 │
+└───────────┴──────────────────┴────────┘
+```
+
+Inactive parts will be deleted approximately 10 minutes after merging.
+
+Another way to view a set of parts and partitions is to go into the directory of the table: `/var/lib/clickhouse/data/<database>/<table>/`. For example:
+
+``` bash
+/var/lib/clickhouse/data/default/visits$ ls -l
+total 40
+drwxr-xr-x 2 clickhouse clickhouse 4096 Feb  1 16:48 201901_1_3_1
+drwxr-xr-x 2 clickhouse clickhouse 4096 Feb  5 16:17 201901_1_9_2_11
+drwxr-xr-x 2 clickhouse clickhouse 4096 Feb  5 15:52 201901_8_8_0
+drwxr-xr-x 2 clickhouse clickhouse 4096 Feb  5 15:52 201901_9_9_0
+drwxr-xr-x 2 clickhouse clickhouse 4096 Feb  5 16:17 201902_10_10_0
+drwxr-xr-x 2 clickhouse clickhouse 4096 Feb  5 16:17 201902_11_11_0
+drwxr-xr-x 2 clickhouse clickhouse 4096 Feb  5 16:19 201902_4_11_2_11
+drwxr-xr-x 2 clickhouse clickhouse 4096 Feb  5 12:09 201902_4_6_1
+drwxr-xr-x 2 clickhouse clickhouse 4096 Feb  1 16:48 detached
+```
+
+The folders ‘201901_1_1_0’, ‘201901_1_7_1’ and so on are the directories of the parts. Each part relates to a corresponding partition and contains data just for a certain month (the table in this example has partitioning by month).
+
+The `detached` directory contains parts that were detached from the table using the [DETACH](../../../sql-reference/statements/alter/partition.md#alter_detach-partition) query. The corrupted parts are also moved to this directory, instead of being deleted. The server does not use the parts from the `detached` directory. You can add, delete, or modify the data in this directory at any time – the server will not know about this until you run the [ATTACH](../../../sql-reference/statements/alter/partition.md#alter_attach-partition) query.
+
+Note that on the operating server, you cannot manually change the set of parts or their data on the file system, since the server will not know about it. For non-replicated tables, you can do this when the server is stopped, but it isn’t recommended. For replicated tables, the set of parts cannot be changed in any case.
+
+ClickHouse allows you to perform operations with the partitions: delete them, copy from one table to another, or create a backup. See the list of all operations in the section [Manipulations With Partitions and Parts](../../../sql-reference/statements/alter/partition.md#alter_manipulations-with-partitions).
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/custom_partitioning_key/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/graphitemergetree.md b/docs/en/reference/engines/table-engines/mergetree-family/graphitemergetree.md
new file mode 100644
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--- /dev/null
+++ b/docs/en/reference/engines/table-engines/mergetree-family/graphitemergetree.md
@@ -0,0 +1,260 @@
+---
+sidebar_position: 90
+sidebar_label:  GraphiteMergeTree
+---
+
+# GraphiteMergeTree {#graphitemergetree}
+
+This engine is designed for thinning and aggregating/averaging (rollup) [Graphite](http://graphite.readthedocs.io/en/latest/index.html) data. It may be helpful to developers who want to use ClickHouse as a data store for Graphite.
+
+You can use any ClickHouse table engine to store the Graphite data if you do not need rollup, but if you need a rollup use `GraphiteMergeTree`. The engine reduces the volume of storage and increases the efficiency of queries from Graphite.
+
+The engine inherits properties from [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md).
+
+## Creating a Table {#creating-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    Path String,
+    Time DateTime,
+    Value <Numeric_type>,
+    Version <Numeric_type>
+    ...
+) ENGINE = GraphiteMergeTree(config_section)
+[PARTITION BY expr]
+[ORDER BY expr]
+[SAMPLE BY expr]
+[SETTINGS name=value, ...]
+```
+
+See a detailed description of the [CREATE TABLE](../../../sql-reference/statements/create/table.md#create-table-query) query.
+
+A table for the Graphite data should have the following columns for the following data:
+
+-   Metric name (Graphite sensor). Data type: `String`.
+
+-   Time of measuring the metric. Data type: `DateTime`.
+
+-   Value of the metric. Data type: any numeric.
+
+-   Version of the metric. Data type: any numeric (ClickHouse saves the rows with the highest version or the last written if versions are the same. Other rows are deleted during the merge of data parts).
+
+The names of these columns should be set in the rollup configuration.
+
+**GraphiteMergeTree parameters**
+
+-   `config_section` — Name of the section in the configuration file, where are the rules of rollup set.
+
+**Query clauses**
+
+When creating a `GraphiteMergeTree` table, the same [clauses](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table) are required, as when creating a `MergeTree` table.
+
+<details markdown="1">
+
+<summary>Deprecated Method for Creating a Table</summary>
+
+:::warning    
+Do not use this method in new projects and, if possible, switch old projects to the method described above.
+:::
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    EventDate Date,
+    Path String,
+    Time DateTime,
+    Value <Numeric_type>,
+    Version <Numeric_type>
+    ...
+) ENGINE [=] GraphiteMergeTree(date-column [, sampling_expression], (primary, key), index_granularity, config_section)
+```
+
+All of the parameters excepting `config_section` have the same meaning as in `MergeTree`.
+
+-   `config_section` — Name of the section in the configuration file, where are the rules of rollup set.
+
+</details>
+
+## Rollup Configuration {#rollup-configuration}
+
+The settings for rollup are defined by the [graphite_rollup](../../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-graphite) parameter in the server configuration. The name of the parameter could be any. You can create several configurations and use them for different tables.
+
+Rollup configuration structure:
+
+      required-columns
+      patterns
+
+### Required Columns {#required-columns}
+
+-   `path_column_name` — The name of the column storing the metric name (Graphite sensor). Default value: `Path`.
+-   `time_column_name` — The name of the column storing the time of measuring the metric. Default value: `Time`.
+-   `value_column_name` — The name of the column storing the value of the metric at the time set in `time_column_name`. Default value: `Value`.
+-   `version_column_name` — The name of the column storing the version of the metric. Default value: `Timestamp`.
+
+### Patterns {#patterns}
+
+Structure of the `patterns` section:
+
+``` text
+pattern
+    rule_type
+    regexp
+    function
+pattern
+    rule_type
+    regexp
+    age + precision
+    ...
+pattern
+    rule_type
+    regexp
+    function
+    age + precision
+    ...
+pattern
+    ...
+default
+    function
+    age + precision
+    ...
+```
+
+:::warning    
+Patterns must be strictly ordered:
+
+1. Patterns without `function` or `retention`.
+1. Patterns with both `function` and `retention`.
+1. Pattern `default`.
+:::
+
+When processing a row, ClickHouse checks the rules in the `pattern` sections. Each of `pattern` (including `default`) sections can contain `function` parameter for aggregation, `retention` parameters or both. If the metric name matches the `regexp`, the rules from the `pattern` section (or sections) are applied; otherwise, the rules from the `default` section are used.
+
+Fields for `pattern` and `default` sections:
+
+-   `rule_type` - a rule's type. It's applied only to a particular metrics. The engine use it to separate plain and tagged metrics. Optional parameter. Default value: `all`.  
+It's unnecessary when performance is not critical, or only one metrics type is used, e.g. plain metrics. By default only one type of rules set is created. Otherwise, if any of special types is defined, two different sets are created. One for plain metrics (root.branch.leaf) and one for tagged metrics (root.branch.leaf;tag1=value1).  
+The default rules are ended up in both sets.  
+Valid values:
+    -   `all` (default) - a universal rule, used when `rule_type` is omitted.
+    -   `plain` - a rule for plain metrics. The field `regexp` is processed as regular expression.
+    -   `tagged` - a rule for tagged metrics (metrics are stored in DB in the format of `someName?tag1=value1&tag2=value2&tag3=value3`). Regular expression must be sorted by tags' names, first tag must be `__name__` if exists. The field `regexp` is processed as regular expression.
+    -   `tag_list` - a rule for tagged matrics, a simple DSL for easier metric description in graphite format `someName;tag1=value1;tag2=value2`, `someName`, or `tag1=value1;tag2=value2`. The field `regexp` is translated into a `tagged` rule. The sorting by tags' names is unnecessary, ti will be done automatically. A tag's value (but not a name) can be set as a regular expression, e.g. `env=(dev|staging)`.
+-   `regexp` – A pattern for the metric name (a regular or DSL).
+-   `age` – The minimum age of the data in seconds.
+-   `precision`– How precisely to define the age of the data in seconds. Should be a divisor for 86400 (seconds in a day).
+-   `function` – The name of the aggregating function to apply to data whose age falls within the range `[age, age + precision]`. Accepted functions: min / max / any / avg. The average is calculated imprecisely, like the average of the averages. 
+
+### Configuration Example without rules types {#configuration-example}
+
+``` xml
+<graphite_rollup>
+    <version_column_name>Version</version_column_name>
+    <pattern>
+        <regexp>click_cost</regexp>
+        <function>any</function>
+        <retention>
+            <age>0</age>
+            <precision>5</precision>
+        </retention>
+        <retention>
+            <age>86400</age>
+            <precision>60</precision>
+        </retention>
+    </pattern>
+    <default>
+        <function>max</function>
+        <retention>
+            <age>0</age>
+            <precision>60</precision>
+        </retention>
+        <retention>
+            <age>3600</age>
+            <precision>300</precision>
+        </retention>
+        <retention>
+            <age>86400</age>
+            <precision>3600</precision>
+        </retention>
+    </default>
+</graphite_rollup>
+```
+
+### Configuration Example with rules types {#configuration-typed-example}
+
+``` xml
+<graphite_rollup>
+    <version_column_name>Version</version_column_name>
+    <pattern>
+        <rule_type>plain</rule_type>
+        <regexp>click_cost</regexp>
+        <function>any</function>
+        <retention>
+            <age>0</age>
+            <precision>5</precision>
+        </retention>
+        <retention>
+            <age>86400</age>
+            <precision>60</precision>
+        </retention>
+    </pattern>
+    <pattern>
+        <rule_type>tagged</rule_type>
+        <regexp>^((.*)|.)min\?</regexp>
+        <function>min</function>
+        <retention>
+            <age>0</age>
+            <precision>5</precision>
+        </retention>
+        <retention>
+            <age>86400</age>
+            <precision>60</precision>
+        </retention>
+    </pattern>
+    <pattern>
+        <rule_type>tagged</rule_type>
+        <regexp><![CDATA[^someName\?(.*&)*tag1=value1(&|$)]]></regexp>
+        <function>min</function>
+        <retention>
+            <age>0</age>
+            <precision>5</precision>
+        </retention>
+        <retention>
+            <age>86400</age>
+            <precision>60</precision>
+        </retention>
+    </pattern>
+    <pattern>
+        <rule_type>tag_list</rule_type>
+        <regexp>someName;tag2=value2</regexp>
+        <retention>
+            <age>0</age>
+            <precision>5</precision>
+        </retention>
+        <retention>
+            <age>86400</age>
+            <precision>60</precision>
+        </retention>
+    </pattern>
+    <default>
+        <function>max</function>
+        <retention>
+            <age>0</age>
+            <precision>60</precision>
+        </retention>
+        <retention>
+            <age>3600</age>
+            <precision>300</precision>
+        </retention>
+        <retention>
+            <age>86400</age>
+            <precision>3600</precision>
+        </retention>
+    </default>
+</graphite_rollup>
+```
+
+
+:::warning
+Data rollup is performed during merges. Usually, for old partitions, merges are not started, so for rollup it is necessary to trigger an unscheduled merge using [optimize](../../../sql-reference/statements/optimize.md). Or use additional tools, for example [graphite-ch-optimizer](https://github.com/innogames/graphite-ch-optimizer).
+:::
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/index.md b/docs/en/reference/engines/table-engines/mergetree-family/index.md
new file mode 100644
index 00000000000..37e7bf5b589
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+++ b/docs/en/reference/engines/table-engines/mergetree-family/index.md
@@ -0,0 +1,16 @@
+---
+sidebar_position: 10
+sidebar_label: MergeTree Family
+---
+
+# MergeTree Engine Family {#mergetree-engine-family}
+
+Table engines from the MergeTree family are the core of ClickHouse data storage capabilities. They provide most features for resilience and high-performance data retrieval: columnar storage, custom partitioning, sparse primary index, secondary data-skipping indexes, etc.
+
+Base [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md) table engine can be considered the default table engine for single-node ClickHouse instances because it is versatile and practical for a wide range of use cases.
+
+For production usage [ReplicatedMergeTree](../../../engines/table-engines/mergetree-family/replication.md) is the way to go, because it adds high-availability to all features of regular MergeTree engine. A bonus is automatic data deduplication on data ingestion, so the software can safely retry if there was some network issue during insert.
+
+All other engines of MergeTree family add extra functionality for some specific use cases. Usually, it’s implemented as additional data manipulation in background.
+
+The main downside of MergeTree engines is that they are rather heavy-weight. So the typical pattern is to have not so many of them. If you need many small tables, for example for temporary data, consider [Log engine family](../../../engines/table-engines/log-family/index.md).
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/mergetree.md b/docs/en/reference/engines/table-engines/mergetree-family/mergetree.md
new file mode 100644
index 00000000000..1195ee55dc7
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/mergetree-family/mergetree.md
@@ -0,0 +1,953 @@
+---
+sidebar_position: 11
+sidebar_label:  MergeTree
+---
+
+# MergeTree {#table_engines-mergetree}
+
+The `MergeTree` engine and other engines of this family (`*MergeTree`) are the most robust ClickHouse table engines.
+
+Engines in the `MergeTree` family are designed for inserting a very large amount of data into a table. The data is quickly written to the table part by part, then rules are applied for merging the parts in the background. This method is much more efficient than continually rewriting the data in storage during insert.
+
+Main features:
+
+-   Stores data sorted by primary key.
+
+    This allows you to create a small sparse index that helps find data faster.
+
+-   Partitions can be used if the [partitioning key](../../../engines/table-engines/mergetree-family/custom-partitioning-key.md) is specified.
+
+    ClickHouse supports certain operations with partitions that are more efficient than general operations on the same data with the same result. ClickHouse also automatically cuts off the partition data where the partitioning key is specified in the query.
+
+-   Data replication support.
+
+    The family of `ReplicatedMergeTree` tables provides data replication. For more information, see [Data replication](../../../engines/table-engines/mergetree-family/replication.md).
+
+-   Data sampling support.
+
+    If necessary, you can set the data sampling method in the table.
+
+:::info
+The [Merge](../../../engines/table-engines/special/merge.md#merge) engine does not belong to the `*MergeTree` family.
+:::
+
+## Creating a Table {#table_engine-mergetree-creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1] [TTL expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2] [TTL expr2],
+    ...
+    INDEX index_name1 expr1 TYPE type1(...) GRANULARITY value1,
+    INDEX index_name2 expr2 TYPE type2(...) GRANULARITY value2,
+    ...
+    PROJECTION projection_name_1 (SELECT <COLUMN LIST EXPR> [GROUP BY] [ORDER BY]),
+    PROJECTION projection_name_2 (SELECT <COLUMN LIST EXPR> [GROUP BY] [ORDER BY])
+) ENGINE = MergeTree()
+ORDER BY expr
+[PARTITION BY expr]
+[PRIMARY KEY expr]
+[SAMPLE BY expr]
+[TTL expr
+    [DELETE|TO DISK 'xxx'|TO VOLUME 'xxx' [, ...] ]
+    [WHERE conditions]
+    [GROUP BY key_expr [SET v1 = aggr_func(v1) [, v2 = aggr_func(v2) ...]] ] ]
+[SETTINGS name=value, ...]
+```
+
+For a description of parameters, see the [CREATE query description](../../../sql-reference/statements/create/table.md).
+
+### Query Clauses {#mergetree-query-clauses}
+
+-   `ENGINE` — Name and parameters of the engine. `ENGINE = MergeTree()`. The `MergeTree` engine does not have parameters.
+
+-   `ORDER BY` — The sorting key.
+
+    A tuple of column names or arbitrary expressions. Example: `ORDER BY (CounterID, EventDate)`.
+
+    ClickHouse uses the sorting key as a primary key if the primary key is not defined obviously by the `PRIMARY KEY` clause.
+
+    Use the `ORDER BY tuple()` syntax, if you do not need sorting. See [Selecting the Primary Key](#selecting-the-primary-key).
+
+-   `PARTITION BY` — The [partitioning key](../../../engines/table-engines/mergetree-family/custom-partitioning-key.md). Optional. In most cases you don't need partition key, and in most other cases you don't need partition key more granular than by months. Partitioning does not speed up queries (in contrast to the ORDER BY expression). You should never use too granular partitioning. Don't partition your data by client identifiers or names (instead make client identifier or name the first column in the ORDER BY expression).
+
+    For partitioning by month, use the `toYYYYMM(date_column)` expression, where `date_column` is a column with a date of the type [Date](../../../sql-reference/data-types/date.md). The partition names here have the `"YYYYMM"` format.
+
+-   `PRIMARY KEY` — The primary key if it [differs from the sorting key](#choosing-a-primary-key-that-differs-from-the-sorting-key). Optional.
+
+    By default the primary key is the same as the sorting key (which is specified by the `ORDER BY` clause). Thus in most cases it is unnecessary to specify a separate `PRIMARY KEY` clause.
+
+-   `SAMPLE BY` — An expression for sampling. Optional.
+
+    If a sampling expression is used, the primary key must contain it. The result of a sampling expression must be an unsigned integer. Example: `SAMPLE BY intHash32(UserID) ORDER BY (CounterID, EventDate, intHash32(UserID))`.
+
+-   `TTL` — A list of rules specifying storage duration of rows and defining logic of automatic parts movement [between disks and volumes](#table_engine-mergetree-multiple-volumes). Optional.
+
+    Expression must have one `Date` or `DateTime` column as a result. Example:
+    `TTL date + INTERVAL 1 DAY`
+
+    Type of the rule `DELETE|TO DISK 'xxx'|TO VOLUME 'xxx'|GROUP BY` specifies an action to be done with the part if the expression is satisfied (reaches current time): removal of expired rows, moving a part (if expression is satisfied for all rows in a part) to specified disk (`TO DISK 'xxx'`) or to volume (`TO VOLUME 'xxx'`), or aggregating values in expired rows. Default type of the rule is removal (`DELETE`). List of multiple rules can be specified, but there should be no more than one `DELETE` rule.
+
+    For more details, see [TTL for columns and tables](#table_engine-mergetree-ttl)
+
+-   `SETTINGS` — Additional parameters that control the behavior of the `MergeTree` (optional):
+
+    -   `index_granularity` — Maximum number of data rows between the marks of an index. Default value: 8192. See [Data Storage](#mergetree-data-storage).
+    -   `index_granularity_bytes` — Maximum size of data granules in bytes. Default value: 10Mb. To restrict the granule size only by number of rows, set to 0 (not recommended). See [Data Storage](#mergetree-data-storage).
+    -   `min_index_granularity_bytes` — Min allowed size of data granules in bytes. Default value: 1024b. To provide a safeguard against accidentally creating tables with very low index_granularity_bytes. See [Data Storage](#mergetree-data-storage).
+    -   `enable_mixed_granularity_parts` — Enables or disables transitioning to control the granule size with the `index_granularity_bytes` setting. Before version 19.11, there was only the `index_granularity` setting for restricting granule size. The `index_granularity_bytes` setting improves ClickHouse performance when selecting data from tables with big rows (tens and hundreds of megabytes). If you have tables with big rows, you can enable this setting for the tables to improve the efficiency of `SELECT` queries.
+    -   `use_minimalistic_part_header_in_zookeeper` — Storage method of the data parts headers in ZooKeeper. If `use_minimalistic_part_header_in_zookeeper=1`, then ZooKeeper stores less data. For more information, see the [setting description](../../../operations/server-configuration-parameters/settings.md#server-settings-use_minimalistic_part_header_in_zookeeper) in “Server configuration parameters”.
+    -   `min_merge_bytes_to_use_direct_io` — The minimum data volume for merge operation that is required for using direct I/O access to the storage disk. When merging data parts, ClickHouse calculates the total storage volume of all the data to be merged. If the volume exceeds `min_merge_bytes_to_use_direct_io` bytes, ClickHouse reads and writes the data to the storage disk using the direct I/O interface (`O_DIRECT` option). If `min_merge_bytes_to_use_direct_io = 0`, then direct I/O is disabled. Default value: `10 * 1024 * 1024 * 1024` bytes.
+        <a name="mergetree_setting-merge_with_ttl_timeout"></a>
+    -   `merge_with_ttl_timeout` — Minimum delay in seconds before repeating a merge with delete TTL. Default value: `14400` seconds (4 hours).
+    -   `merge_with_recompression_ttl_timeout` — Minimum delay in seconds before repeating a merge with recompression TTL. Default value: `14400` seconds (4 hours).
+    -   `try_fetch_recompressed_part_timeout` — Timeout (in seconds) before starting merge with recompression. During this time ClickHouse tries to fetch recompressed part from replica which assigned this merge with recompression. Default value: `7200` seconds (2 hours).
+    -   `write_final_mark` — Enables or disables writing the final index mark at the end of data part (after the last byte). Default value: 1. Don’t turn it off.
+    -   `merge_max_block_size` — Maximum number of rows in block for merge operations. Default value: 8192.
+    -   `storage_policy` — Storage policy. See [Using Multiple Block Devices for Data Storage](#table_engine-mergetree-multiple-volumes).
+    -   `min_bytes_for_wide_part`, `min_rows_for_wide_part` — Minimum number of bytes/rows in a data part that can be stored in `Wide` format. You can set one, both or none of these settings. See [Data Storage](#mergetree-data-storage).
+    -   `max_parts_in_total` — Maximum number of parts in all partitions.
+	-   `max_compress_block_size` — Maximum size of blocks of uncompressed data before compressing for writing to a table. You can also specify this setting in the global settings (see [max_compress_block_size](../../../operations/settings/settings.md#max-compress-block-size) setting). The value specified when table is created overrides the global value for this setting.
+	-   `min_compress_block_size` — Minimum size of blocks of uncompressed data required for compression when writing the next mark. You can also specify this setting in the global settings (see [min_compress_block_size](../../../operations/settings/settings.md#min-compress-block-size) setting). The value specified when table is created overrides the global value for this setting.
+    -   `max_partitions_to_read` — Limits the maximum number of partitions that can be accessed in one query. You can also specify setting [max_partitions_to_read](../../../operations/settings/merge-tree-settings.md#max-partitions-to-read) in the global setting.
+
+**Example of Sections Setting**
+
+``` sql
+ENGINE MergeTree() PARTITION BY toYYYYMM(EventDate) ORDER BY (CounterID, EventDate, intHash32(UserID)) SAMPLE BY intHash32(UserID) SETTINGS index_granularity=8192
+```
+
+In the example, we set partitioning by month.
+
+We also set an expression for sampling as a hash by the user ID. This allows you to pseudorandomize the data in the table for each `CounterID` and `EventDate`. If you define a [SAMPLE](../../../sql-reference/statements/select/sample.md#select-sample-clause) clause when selecting the data, ClickHouse will return an evenly pseudorandom data sample for a subset of users.
+
+The `index_granularity` setting can be omitted because 8192 is the default value.
+
+<details markdown="1">
+
+<summary>Deprecated Method for Creating a Table</summary>
+
+:::warning
+Do not use this method in new projects. If possible, switch old projects to the method described above.
+:::
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE [=] MergeTree(date-column [, sampling_expression], (primary, key), index_granularity)
+```
+
+**MergeTree() Parameters**
+
+-   `date-column` — The name of a column of the [Date](../../../sql-reference/data-types/date.md) type. ClickHouse automatically creates partitions by month based on this column. The partition names are in the `"YYYYMM"` format.
+-   `sampling_expression` — An expression for sampling.
+-   `(primary, key)` — Primary key. Type: [Tuple()](../../../sql-reference/data-types/tuple.md)
+-   `index_granularity` — The granularity of an index. The number of data rows between the “marks” of an index. The value 8192 is appropriate for most tasks.
+
+**Example**
+
+``` sql
+MergeTree(EventDate, intHash32(UserID), (CounterID, EventDate, intHash32(UserID)), 8192)
+```
+
+The `MergeTree` engine is configured in the same way as in the example above for the main engine configuration method.
+</details>
+
+## Data Storage {#mergetree-data-storage}
+
+A table consists of data parts sorted by primary key.
+
+When data is inserted in a table, separate data parts are created and each of them is lexicographically sorted by primary key. For example, if the primary key is `(CounterID, Date)`, the data in the part is sorted by `CounterID`, and within each `CounterID`, it is ordered by `Date`.
+
+Data belonging to different partitions are separated into different parts. In the background, ClickHouse merges data parts for more efficient storage. Parts belonging to different partitions are not merged. The merge mechanism does not guarantee that all rows with the same primary key will be in the same data part.
+
+Data parts can be stored in `Wide` or `Compact` format. In `Wide` format each column is stored in a separate file in a filesystem, in `Compact` format all columns are stored in one file. `Compact` format can be used to increase performance of small and frequent inserts.
+
+Data storing format is controlled by the `min_bytes_for_wide_part` and `min_rows_for_wide_part` settings of the table engine. If the number of bytes or rows in a data part is less then the corresponding setting's value, the part is stored in `Compact` format. Otherwise it is stored in `Wide` format. If none of these settings is set, data parts are stored in `Wide` format.
+
+Each data part is logically divided into granules. A granule is the smallest indivisible data set that ClickHouse reads when selecting data. ClickHouse does not split rows or values, so each granule always contains an integer number of rows. The first row of a granule is marked with the value of the primary key for the row. For each data part, ClickHouse creates an index file that stores the marks. For each column, whether it’s in the primary key or not, ClickHouse also stores the same marks. These marks let you find data directly in column files.
+
+The granule size is restricted by the `index_granularity` and `index_granularity_bytes` settings of the table engine. The number of rows in a granule lays in the `[1, index_granularity]` range, depending on the size of the rows. The size of a granule can exceed `index_granularity_bytes` if the size of a single row is greater than the value of the setting. In this case, the size of the granule equals the size of the row.
+
+## Primary Keys and Indexes in Queries {#primary-keys-and-indexes-in-queries}
+
+Take the `(CounterID, Date)` primary key as an example. In this case, the sorting and index can be illustrated as follows:
+
+      Whole data:     [---------------------------------------------]
+      CounterID:      [aaaaaaaaaaaaaaaaaabbbbcdeeeeeeeeeeeeefgggggggghhhhhhhhhiiiiiiiiikllllllll]
+      Date:           [1111111222222233331233211111222222333211111112122222223111112223311122333]
+      Marks:           |      |      |      |      |      |      |      |      |      |      |
+                      a,1    a,2    a,3    b,3    e,2    e,3    g,1    h,2    i,1    i,3    l,3
+      Marks numbers:   0      1      2      3      4      5      6      7      8      9      10
+
+If the data query specifies:
+
+-   `CounterID in ('a', 'h')`, the server reads the data in the ranges of marks `[0, 3)` and `[6, 8)`.
+-   `CounterID IN ('a', 'h') AND Date = 3`, the server reads the data in the ranges of marks `[1, 3)` and `[7, 8)`.
+-   `Date = 3`, the server reads the data in the range of marks `[1, 10]`.
+
+The examples above show that it is always more effective to use an index than a full scan.
+
+A sparse index allows extra data to be read. When reading a single range of the primary key, up to `index_granularity * 2` extra rows in each data block can be read.
+
+Sparse indexes allow you to work with a very large number of table rows, because in most cases, such indexes fit in the computer’s RAM.
+
+ClickHouse does not require a unique primary key. You can insert multiple rows with the same primary key.
+
+You can use `Nullable`-typed expressions in the `PRIMARY KEY` and `ORDER BY` clauses but it is strongly discouraged. To allow this feature, turn on the [allow_nullable_key](../../../operations/settings/settings.md#allow-nullable-key) setting. The [NULLS_LAST](../../../sql-reference/statements/select/order-by.md#sorting-of-special-values) principle applies for `NULL` values in the `ORDER BY` clause.
+
+### Selecting the Primary Key {#selecting-the-primary-key}
+
+The number of columns in the primary key is not explicitly limited. Depending on the data structure, you can include more or fewer columns in the primary key. This may:
+
+-   Improve the performance of an index.
+
+    If the primary key is `(a, b)`, then adding another column `c` will improve the performance if the following conditions are met:
+
+    -   There are queries with a condition on column `c`.
+    -   Long data ranges (several times longer than the `index_granularity`) with identical values for `(a, b)` are common. In other words, when adding another column allows you to skip quite long data ranges.
+
+-   Improve data compression.
+
+    ClickHouse sorts data by primary key, so the higher the consistency, the better the compression.
+
+-   Provide additional logic when merging data parts in the [CollapsingMergeTree](../../../engines/table-engines/mergetree-family/collapsingmergetree.md#table_engine-collapsingmergetree) and [SummingMergeTree](../../../engines/table-engines/mergetree-family/summingmergetree.md) engines.
+
+    In this case it makes sense to specify the *sorting key* that is different from the primary key.
+
+A long primary key will negatively affect the insert performance and memory consumption, but extra columns in the primary key do not affect ClickHouse performance during `SELECT` queries.
+
+You can create a table without a primary key using the `ORDER BY tuple()` syntax. In this case, ClickHouse stores data in the order of inserting. If you want to save data order when inserting data by `INSERT ... SELECT` queries, set [max_insert_threads = 1](../../../operations/settings/settings.md#settings-max-insert-threads).
+
+To select data in the initial order, use [single-threaded](../../../operations/settings/settings.md#settings-max_threads) `SELECT` queries.
+
+### Choosing a Primary Key that Differs from the Sorting Key {#choosing-a-primary-key-that-differs-from-the-sorting-key}
+
+It is possible to specify a primary key (an expression with values that are written in the index file for each mark) that is different from the sorting key (an expression for sorting the rows in data parts). In this case the primary key expression tuple must be a prefix of the sorting key expression tuple.
+
+This feature is helpful when using the [SummingMergeTree](../../../engines/table-engines/mergetree-family/summingmergetree.md) and
+[AggregatingMergeTree](../../../engines/table-engines/mergetree-family/aggregatingmergetree.md) table engines. In a common case when using these engines, the table has two types of columns: *dimensions* and *measures*. Typical queries aggregate values of measure columns with arbitrary `GROUP BY` and filtering by dimensions. Because SummingMergeTree and AggregatingMergeTree aggregate rows with the same value of the sorting key, it is natural to add all dimensions to it. As a result, the key expression consists of a long list of columns and this list must be frequently updated with newly added dimensions.
+
+In this case it makes sense to leave only a few columns in the primary key that will provide efficient range scans and add the remaining dimension columns to the sorting key tuple.
+
+[ALTER](../../../sql-reference/statements/alter/index.md) of the sorting key is a lightweight operation because when a new column is simultaneously added to the table and to the sorting key, existing data parts do not need to be changed. Since the old sorting key is a prefix of the new sorting key and there is no data in the newly added column, the data is sorted by both the old and new sorting keys at the moment of table modification.
+
+### Use of Indexes and Partitions in Queries {#use-of-indexes-and-partitions-in-queries}
+
+For `SELECT` queries, ClickHouse analyzes whether an index can be used. An index can be used if the `WHERE/PREWHERE` clause has an expression (as one of the conjunction elements, or entirely) that represents an equality or inequality comparison operation, or if it has `IN` or `LIKE` with a fixed prefix on columns or expressions that are in the primary key or partitioning key, or on certain partially repetitive functions of these columns, or logical relationships of these expressions.
+
+Thus, it is possible to quickly run queries on one or many ranges of the primary key. In this example, queries will be fast when run for a specific tracking tag, for a specific tag and date range, for a specific tag and date, for multiple tags with a date range, and so on.
+
+Let’s look at the engine configured as follows:
+
+      ENGINE MergeTree() PARTITION BY toYYYYMM(EventDate) ORDER BY (CounterID, EventDate) SETTINGS index_granularity=8192
+
+In this case, in queries:
+
+``` sql
+SELECT count() FROM table WHERE EventDate = toDate(now()) AND CounterID = 34
+SELECT count() FROM table WHERE EventDate = toDate(now()) AND (CounterID = 34 OR CounterID = 42)
+SELECT count() FROM table WHERE ((EventDate >= toDate('2014-01-01') AND EventDate <= toDate('2014-01-31')) OR EventDate = toDate('2014-05-01')) AND CounterID IN (101500, 731962, 160656) AND (CounterID = 101500 OR EventDate != toDate('2014-05-01'))
+```
+
+ClickHouse will use the primary key index to trim improper data and the monthly partitioning key to trim partitions that are in improper date ranges.
+
+The queries above show that the index is used even for complex expressions. Reading from the table is organized so that using the index can’t be slower than a full scan.
+
+In the example below, the index can’t be used.
+
+``` sql
+SELECT count() FROM table WHERE CounterID = 34 OR URL LIKE '%upyachka%'
+```
+
+To check whether ClickHouse can use the index when running a query, use the settings [force_index_by_date](../../../operations/settings/settings.md#settings-force_index_by_date) and [force_primary_key](../../../operations/settings/settings.md#force-primary-key).
+
+The key for partitioning by month allows reading only those data blocks which contain dates from the proper range. In this case, the data block may contain data for many dates (up to an entire month). Within a block, data is sorted by primary key, which might not contain the date as the first column. Because of this, using a query with only a date condition that does not specify the primary key prefix will cause more data to be read than for a single date.
+
+### Use of Index for Partially-monotonic Primary Keys {#use-of-index-for-partially-monotonic-primary-keys}
+
+Consider, for example, the days of the month. They form a [monotonic sequence](https://en.wikipedia.org/wiki/Monotonic_function) for one month, but not monotonic for more extended periods. This is a partially-monotonic sequence. If a user creates the table with partially-monotonic primary key, ClickHouse creates a sparse index as usual. When a user selects data from this kind of table, ClickHouse analyzes the query conditions. If the user wants to get data between two marks of the index and both these marks fall within one month, ClickHouse can use the index in this particular case because it can calculate the distance between the parameters of a query and index marks.
+
+ClickHouse cannot use an index if the values of the primary key in the query parameter range do not represent a monotonic sequence. In this case, ClickHouse uses the full scan method.
+
+ClickHouse uses this logic not only for days of the month sequences, but for any primary key that represents a partially-monotonic sequence.
+
+### Data Skipping Indexes {#table_engine-mergetree-data_skipping-indexes}
+
+The index declaration is in the columns section of the `CREATE` query.
+
+``` sql
+INDEX index_name expr TYPE type(...) GRANULARITY granularity_value
+```
+
+For tables from the `*MergeTree` family, data skipping indices can be specified.
+
+These indices aggregate some information about the specified expression on blocks, which consist of `granularity_value` granules (the size of the granule is specified using the `index_granularity` setting in the table engine). Then these aggregates are used in `SELECT` queries for reducing the amount of data to read from the disk by skipping big blocks of data where the `where` query cannot be satisfied.
+
+**Example**
+
+``` sql
+CREATE TABLE table_name
+(
+    u64 UInt64,
+    i32 Int32,
+    s String,
+    ...
+    INDEX a (u64 * i32, s) TYPE minmax GRANULARITY 3,
+    INDEX b (u64 * length(s)) TYPE set(1000) GRANULARITY 4
+) ENGINE = MergeTree()
+...
+```
+
+Indices from the example can be used by ClickHouse to reduce the amount of data to read from disk in the following queries:
+
+``` sql
+SELECT count() FROM table WHERE s &lt; 'z'
+SELECT count() FROM table WHERE u64 * i32 == 10 AND u64 * length(s) &gt;= 1234
+```
+
+#### Available Types of Indices {#available-types-of-indices}
+
+-   `minmax`
+
+    Stores extremes of the specified expression (if the expression is `tuple`, then it stores extremes for each element of `tuple`), uses stored info for skipping blocks of data like the primary key.
+
+-   `set(max_rows)`
+
+    Stores unique values of the specified expression (no more than `max_rows` rows, `max_rows=0` means “no limits”). Uses the values to check if the `WHERE` expression is not satisfiable on a block of data.
+
+-   `ngrambf_v1(n, size_of_bloom_filter_in_bytes, number_of_hash_functions, random_seed)`
+
+    Stores a [Bloom filter](https://en.wikipedia.org/wiki/Bloom_filter) that contains all ngrams from a block of data. Works only with datatypes: [String](../../../sql-reference/data-types/string.md), [FixedString](../../../sql-reference/data-types/fixedstring.md) and [Map](../../../sql-reference/data-types/map.md). Can be used for optimization of `EQUALS`, `LIKE` and `IN` expressions.
+
+    -   `n` — ngram size,
+    -   `size_of_bloom_filter_in_bytes` — Bloom filter size in bytes (you can use large values here, for example, 256 or 512, because it can be compressed well).
+    -   `number_of_hash_functions` — The number of hash functions used in the Bloom filter.
+    -   `random_seed` — The seed for Bloom filter hash functions.
+
+-   `tokenbf_v1(size_of_bloom_filter_in_bytes, number_of_hash_functions, random_seed)`
+
+    The same as `ngrambf_v1`, but stores tokens instead of ngrams. Tokens are sequences separated by non-alphanumeric characters.
+
+-   `bloom_filter([false_positive])` — Stores a [Bloom filter](https://en.wikipedia.org/wiki/Bloom_filter) for the specified columns.
+
+    The optional `false_positive` parameter is the probability of receiving a false positive response from the filter. Possible values: (0, 1). Default value: 0.025.
+
+    Supported data types: `Int*`, `UInt*`, `Float*`, `Enum`, `Date`, `DateTime`, `String`, `FixedString`, `Array`, `LowCardinality`, `Nullable`, `UUID`, `Map`.
+
+    For `Map` data type client can specify if index should be created for keys or values using [mapKeys](../../../sql-reference/functions/tuple-map-functions.md#mapkeys) or [mapValues](../../../sql-reference/functions/tuple-map-functions.md#mapvalues) function.
+
+    The following functions can use the filter: [equals](../../../sql-reference/functions/comparison-functions.md), [notEquals](../../../sql-reference/functions/comparison-functions.md), [in](../../../sql-reference/functions/in-functions.md), [notIn](../../../sql-reference/functions/in-functions.md), [has](../../../sql-reference/functions/array-functions.md#hasarr-elem), [hasAny](../../../sql-reference/functions/array-functions.md#hasany), [hasAll](../../../sql-reference/functions/array-functions.md#hasall).
+
+    Example of index creation for `Map` data type
+
+```
+INDEX map_key_index mapKeys(map_column) TYPE bloom_filter GRANULARITY 1
+INDEX map_key_index mapValues(map_column) TYPE bloom_filter GRANULARITY 1
+```
+
+
+``` sql
+INDEX sample_index (u64 * length(s)) TYPE minmax GRANULARITY 4
+INDEX sample_index2 (u64 * length(str), i32 + f64 * 100, date, str) TYPE set(100) GRANULARITY 4
+INDEX sample_index3 (lower(str), str) TYPE ngrambf_v1(3, 256, 2, 0) GRANULARITY 4
+```
+
+#### Functions Support {#functions-support}
+
+Conditions in the `WHERE` clause contains calls of the functions that operate with columns. If the column is a part of an index, ClickHouse tries to use this index when performing the functions. ClickHouse supports different subsets of functions for using indexes.
+
+The `set` index can be used with all functions. Function subsets for other indexes are shown in the table below.
+
+| Function (operator) / Index                                                                                | primary key | minmax | ngrambf_v1 | tokenbf_v1 | bloom_filter |
+|------------------------------------------------------------------------------------------------------------|-------------|--------|-------------|-------------|---------------|
+| [equals (=, ==)](../../../sql-reference/functions/comparison-functions.md#function-equals)                 | ✔           | ✔      | ✔           | ✔           | ✔             |
+| [notEquals(!=, &lt;&gt;)](../../../sql-reference/functions/comparison-functions.md#function-notequals)         | ✔           | ✔      | ✔           | ✔           | ✔             |
+| [like](../../../sql-reference/functions/string-search-functions.md#function-like)                          | ✔           | ✔      | ✔           | ✔           | ✗             |
+| [notLike](../../../sql-reference/functions/string-search-functions.md#function-notlike)                    | ✔           | ✔      | ✔           | ✔           | ✗             |
+| [startsWith](../../../sql-reference/functions/string-functions.md#startswith)                              | ✔           | ✔      | ✔           | ✔           | ✗             |
+| [endsWith](../../../sql-reference/functions/string-functions.md#endswith)                                  | ✗           | ✗      | ✔           | ✔           | ✗             |
+| [multiSearchAny](../../../sql-reference/functions/string-search-functions.md#function-multisearchany)      | ✗           | ✗      | ✔           | ✗           | ✗             |
+| [in](../../../sql-reference/functions/in-functions.md#in-functions)                                        | ✔           | ✔      | ✔           | ✔           | ✔             |
+| [notIn](../../../sql-reference/functions/in-functions.md#in-functions)                                     | ✔           | ✔      | ✔           | ✔           | ✔             |
+| [less (<)](../../../sql-reference/functions/comparison-functions.md#function-less)                        | ✔           | ✔      | ✗           | ✗           | ✗             |
+| [greater (>)](../../../sql-reference/functions/comparison-functions.md#function-greater)                  | ✔           | ✔      | ✗           | ✗           | ✗             |
+| [lessOrEquals (<=)](../../../sql-reference/functions/comparison-functions.md#function-lessorequals)       | ✔           | ✔      | ✗           | ✗           | ✗             |
+| [greaterOrEquals (>=)](../../../sql-reference/functions/comparison-functions.md#function-greaterorequals) | ✔           | ✔      | ✗           | ✗           | ✗             |
+| [empty](../../../sql-reference/functions/array-functions.md#function-empty)                                | ✔           | ✔      | ✗           | ✗           | ✗             |
+| [notEmpty](../../../sql-reference/functions/array-functions.md#function-notempty)                          | ✔           | ✔      | ✗           | ✗           | ✗             |
+| hasToken                                                                                                   | ✗           | ✗      | ✗           | ✔           | ✗             |
+
+Functions with a constant argument that is less than ngram size can’t be used by `ngrambf_v1` for query optimization.
+
+:::note
+Bloom filters can have false positive matches, so the `ngrambf_v1`, `tokenbf_v1`, and `bloom_filter` indexes can not be used for optimizing queries where the result of a function is expected to be false.
+
+For example:
+
+-   Can be optimized:
+    -   `s LIKE '%test%'`
+    -   `NOT s NOT LIKE '%test%'`
+    -   `s = 1`
+    -   `NOT s != 1`
+    -   `startsWith(s, 'test')`
+-   Can not be optimized:
+    -   `NOT s LIKE '%test%'`
+    -   `s NOT LIKE '%test%'`
+    -   `NOT s = 1`
+    -   `s != 1`
+    -   `NOT startsWith(s, 'test')`
+:::
+
+## Projections {#projections}
+Projections are like [materialized views](../../../sql-reference/statements/create/view.md#materialized) but defined in part-level. It provides consistency guarantees along with automatic usage in queries.
+
+Projections are an experimental feature. To enable them you must set the [allow_experimental_projection_optimization](../../../operations/settings/settings.md#allow-experimental-projection-optimization) to `1`. See also the [force_optimize_projection](../../../operations/settings/settings.md#force-optimize-projection) setting.
+
+Projections are not supported in the `SELECT` statements with the [FINAL](../../../sql-reference/statements/select/from.md#select-from-final) modifier.
+
+### Projection Query {#projection-query}
+A projection query is what defines a projection. It implicitly selects data from the parent table.
+**Syntax**
+
+```sql
+SELECT <column list expr> [GROUP BY] <group keys expr> [ORDER BY] <expr>
+```
+
+Projections can be modified or dropped with the [ALTER](../../../sql-reference/statements/alter/projection.md) statement.
+
+### Projection Storage {#projection-storage}
+Projections are stored inside the part directory. It's similar to an index but contains a subdirectory that stores an anonymous `MergeTree` table's part. The table is induced by the definition query of the projection. If there is a `GROUP BY` clause, the underlying storage engine becomes [AggregatingMergeTree](aggregatingmergetree.md), and all aggregate functions are converted to `AggregateFunction`. If there is an `ORDER BY` clause, the `MergeTree` table uses it as its primary key expression. During the merge process the projection part is merged via its storage's merge routine. The checksum of the parent table's part is combined with the projection's part. Other maintenance jobs are similar to skip indices.
+
+### Query Analysis {#projection-query-analysis}
+1. Check if the projection can be used to answer the given query, that is, it generates the same answer as querying the base table.
+2. Select the best feasible match, which contains the least granules to read.
+3. The query pipeline which uses projections will be different from the one that uses the original parts. If the projection is absent in some parts, we can add the pipeline to "project" it on the fly.
+
+## Concurrent Data Access {#concurrent-data-access}
+
+For concurrent table access, we use multi-versioning. In other words, when a table is simultaneously read and updated, data is read from a set of parts that is current at the time of the query. There are no lengthy locks. Inserts do not get in the way of read operations.
+
+Reading from a table is automatically parallelized.
+
+## TTL for Columns and Tables {#table_engine-mergetree-ttl}
+
+Determines the lifetime of values.
+
+The `TTL` clause can be set for the whole table and for each individual column. Table-level `TTL` can also specify the logic of automatic moving data between disks and volumes, or recompressing parts where all the data has been expired.
+
+Expressions must evaluate to [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md) data type.
+
+**Syntax**
+
+Setting time-to-live for a column:
+
+``` sql
+TTL time_column
+TTL time_column + interval
+```
+
+To define `interval`, use [time interval](../../../sql-reference/operators/index.md#operators-datetime) operators, for example:
+
+``` sql
+TTL date_time + INTERVAL 1 MONTH
+TTL date_time + INTERVAL 15 HOUR
+```
+
+### Column TTL {#mergetree-column-ttl}
+
+When the values in the column expire, ClickHouse replaces them with the default values for the column data type. If all the column values in the data part expire, ClickHouse deletes this column from the data part in a filesystem.
+
+The `TTL` clause can’t be used for key columns.
+
+**Examples**
+
+Creating a table with `TTL`:
+
+``` sql
+CREATE TABLE example_table
+(
+    d DateTime,
+    a Int TTL d + INTERVAL 1 MONTH,
+    b Int TTL d + INTERVAL 1 MONTH,
+    c String
+)
+ENGINE = MergeTree
+PARTITION BY toYYYYMM(d)
+ORDER BY d;
+```
+
+Adding TTL to a column of an existing table
+
+``` sql
+ALTER TABLE example_table
+    MODIFY COLUMN
+    c String TTL d + INTERVAL 1 DAY;
+```
+
+Altering TTL of the column
+
+``` sql
+ALTER TABLE example_table
+    MODIFY COLUMN
+    c String TTL d + INTERVAL 1 MONTH;
+```
+
+### Table TTL {#mergetree-table-ttl}
+
+Table can have an expression for removal of expired rows, and multiple expressions for automatic move of parts between [disks or volumes](#table_engine-mergetree-multiple-volumes). When rows in the table expire, ClickHouse deletes all corresponding rows. For parts moving or recompressing, all rows of a part must satisfy the `TTL` expression criteria.
+
+``` sql
+TTL expr
+    [DELETE|RECOMPRESS codec_name1|TO DISK 'xxx'|TO VOLUME 'xxx'][, DELETE|RECOMPRESS codec_name2|TO DISK 'aaa'|TO VOLUME 'bbb'] ...
+    [WHERE conditions]
+    [GROUP BY key_expr [SET v1 = aggr_func(v1) [, v2 = aggr_func(v2) ...]] ]
+```
+
+Type of TTL rule may follow each TTL expression. It affects an action which is to be done once the expression is satisfied (reaches current time):
+
+-   `DELETE` - delete expired rows (default action);
+-   `RECOMPRESS codec_name` - recompress data part with the `codec_name`;
+-   `TO DISK 'aaa'` - move part to the disk `aaa`;
+-   `TO VOLUME 'bbb'` - move part to the disk `bbb`;
+-   `GROUP BY` - aggregate expired rows.
+
+With `WHERE` clause you may specify which of the expired rows to delete or aggregate (it cannot be applied to moves or recompression).
+
+`GROUP BY` expression must be a prefix of the table primary key.
+
+If a column is not part of the `GROUP BY` expression and is not set explicitly in the `SET` clause, in result row it contains an occasional value from the grouped rows (as if aggregate function `any` is applied to it).
+
+**Examples**
+
+Creating a table with `TTL`:
+
+``` sql
+CREATE TABLE example_table
+(
+    d DateTime,
+    a Int
+)
+ENGINE = MergeTree
+PARTITION BY toYYYYMM(d)
+ORDER BY d
+TTL d + INTERVAL 1 MONTH [DELETE],
+    d + INTERVAL 1 WEEK TO VOLUME 'aaa',
+    d + INTERVAL 2 WEEK TO DISK 'bbb';
+```
+
+Altering `TTL` of the table:
+
+``` sql
+ALTER TABLE example_table
+    MODIFY TTL d + INTERVAL 1 DAY;
+```
+
+Creating a table, where the rows are expired after one month. The expired rows where dates are Mondays are deleted:
+
+``` sql
+CREATE TABLE table_with_where
+(
+    d DateTime,
+    a Int
+)
+ENGINE = MergeTree
+PARTITION BY toYYYYMM(d)
+ORDER BY d
+TTL d + INTERVAL 1 MONTH DELETE WHERE toDayOfWeek(d) = 1;
+```
+
+Creating a table, where expired rows are recompressed:
+
+```sql
+CREATE TABLE table_for_recompression
+(
+    d DateTime,
+    key UInt64,
+    value String
+) ENGINE MergeTree()
+ORDER BY tuple()
+PARTITION BY key
+TTL d + INTERVAL 1 MONTH RECOMPRESS CODEC(ZSTD(17)), d + INTERVAL 1 YEAR RECOMPRESS CODEC(LZ4HC(10))
+SETTINGS min_rows_for_wide_part = 0, min_bytes_for_wide_part = 0;
+```
+
+Creating a table, where expired rows are aggregated. In result rows `x` contains the maximum value accross the grouped rows, `y` — the minimum value, and `d` — any occasional value from grouped rows.
+
+``` sql
+CREATE TABLE table_for_aggregation
+(
+    d DateTime,
+    k1 Int,
+    k2 Int,
+    x Int,
+    y Int
+)
+ENGINE = MergeTree
+ORDER BY (k1, k2)
+TTL d + INTERVAL 1 MONTH GROUP BY k1, k2 SET x = max(x), y = min(y);
+```
+
+### Removing Expired Data {#mergetree-removing-expired-data}
+
+Data with an expired `TTL` is removed when ClickHouse merges data parts.
+
+When ClickHouse detects that data is expired, it performs an off-schedule merge. To control the frequency of such merges, you can set `merge_with_ttl_timeout`. If the value is too low, it will perform many off-schedule merges that may consume a lot of resources.
+
+If you perform the `SELECT` query between merges, you may get expired data. To avoid it, use the [OPTIMIZE](../../../sql-reference/statements/optimize.md) query before `SELECT`.
+
+**See Also**
+
+- [ttl_only_drop_parts](../../../operations/settings/settings.md#ttl_only_drop_parts) setting
+
+
+## Using Multiple Block Devices for Data Storage {#table_engine-mergetree-multiple-volumes}
+
+### Introduction {#introduction}
+
+`MergeTree` family table engines can store data on multiple block devices. For example, it can be useful when the data of a certain table are implicitly split into “hot” and “cold”. The most recent data is regularly requested but requires only a small amount of space. On the contrary, the fat-tailed historical data is requested rarely. If several disks are available, the “hot” data may be located on fast disks (for example, NVMe SSDs or in memory), while the “cold” data - on relatively slow ones (for example, HDD).
+
+Data part is the minimum movable unit for `MergeTree`-engine tables. The data belonging to one part are stored on one disk. Data parts can be moved between disks in the background (according to user settings) as well as by means of the [ALTER](../../../sql-reference/statements/alter/partition.md#alter_move-partition) queries.
+
+### Terms {#terms}
+
+-   Disk — Block device mounted to the filesystem.
+-   Default disk — Disk that stores the path specified in the [path](../../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-path) server setting.
+-   Volume — Ordered set of equal disks (similar to [JBOD](https://en.wikipedia.org/wiki/Non-RAID_drive_architectures)).
+-   Storage policy — Set of volumes and the rules for moving data between them.
+
+The names given to the described entities can be found in the system tables, [system.storage_policies](../../../operations/system-tables/storage_policies.md#system_tables-storage_policies) and [system.disks](../../../operations/system-tables/disks.md#system_tables-disks). To apply one of the configured storage policies for a table, use the `storage_policy` setting of `MergeTree`-engine family tables.
+
+### Configuration {#table_engine-mergetree-multiple-volumes_configure}
+
+Disks, volumes and storage policies should be declared inside the `<storage_configuration>` tag either in the main file `config.xml` or in a distinct file in the `config.d` directory.
+
+Configuration structure:
+
+``` xml
+<storage_configuration>
+    <disks>
+        <disk_name_1> <!-- disk name -->
+            <path>/mnt/fast_ssd/clickhouse/</path>
+        </disk_name_1>
+        <disk_name_2>
+            <path>/mnt/hdd1/clickhouse/</path>
+            <keep_free_space_bytes>10485760</keep_free_space_bytes>
+        </disk_name_2>
+        <disk_name_3>
+            <path>/mnt/hdd2/clickhouse/</path>
+            <keep_free_space_bytes>10485760</keep_free_space_bytes>
+        </disk_name_3>
+
+        ...
+    </disks>
+
+    ...
+</storage_configuration>
+```
+
+Tags:
+
+-   `<disk_name_N>` — Disk name. Names must be different for all disks.
+-   `path` — path under which a server will store data (`data` and `shadow` folders), should be terminated with ‘/’.
+-   `keep_free_space_bytes` — the amount of free disk space to be reserved.
+
+The order of the disk definition is not important.
+
+Storage policies configuration markup:
+
+``` xml
+<storage_configuration>
+    ...
+    <policies>
+        <policy_name_1>
+            <volumes>
+                <volume_name_1>
+                    <disk>disk_name_from_disks_configuration</disk>
+                    <max_data_part_size_bytes>1073741824</max_data_part_size_bytes>
+                </volume_name_1>
+                <volume_name_2>
+                    <!-- configuration -->
+                </volume_name_2>
+                <!-- more volumes -->
+            </volumes>
+            <move_factor>0.2</move_factor>
+        </policy_name_1>
+        <policy_name_2>
+            <!-- configuration -->
+        </policy_name_2>
+
+        <!-- more policies -->
+    </policies>
+    ...
+</storage_configuration>
+```
+
+Tags:
+
+-   `policy_name_N` — Policy name. Policy names must be unique.
+-   `volume_name_N` — Volume name. Volume names must be unique.
+-   `disk` — a disk within a volume.
+-   `max_data_part_size_bytes` — the maximum size of a part that can be stored on any of the volume’s disks. If the a size of a merged part estimated to be bigger than `max_data_part_size_bytes` then this part will be written to a next volume. Basically this feature allows to keep new/small parts on a hot (SSD) volume and move them to a cold (HDD) volume when they reach large size. Do not use this setting if your policy has only one volume.
+-   `move_factor` — when the amount of available space gets lower than this factor, data automatically starts to move on the next volume if any (by default, 0.1). ClickHouse sorts existing parts by size from largest to smallest (in descending order) and selects parts with the total size that is sufficient to meet the `move_factor` condition. If the total size of all parts is insufficient, all parts will be moved. 
+-   `prefer_not_to_merge` — Disables merging of data parts on this volume. When this setting is enabled, merging data on this volume is not allowed. This allows controlling how ClickHouse works with slow disks.
+
+Cofiguration examples:
+
+``` xml
+<storage_configuration>
+    ...
+    <policies>
+        <hdd_in_order> <!-- policy name -->
+            <volumes>
+                <single> <!-- volume name -->
+                    <disk>disk1</disk>
+                    <disk>disk2</disk>
+                </single>
+            </volumes>
+        </hdd_in_order>
+
+        <moving_from_ssd_to_hdd>
+            <volumes>
+                <hot>
+                    <disk>fast_ssd</disk>
+                    <max_data_part_size_bytes>1073741824</max_data_part_size_bytes>
+                </hot>
+                <cold>
+                    <disk>disk1</disk>
+                </cold>
+            </volumes>
+            <move_factor>0.2</move_factor>
+        </moving_from_ssd_to_hdd>
+
+		<small_jbod_with_external_no_merges>
+            <volumes>
+                <main>
+                    <disk>jbod1</disk>
+                </main>
+                <external>
+                    <disk>external</disk>
+                    <prefer_not_to_merge>true</prefer_not_to_merge>
+                </external>
+            </volumes>
+        </small_jbod_with_external_no_merges>
+    </policies>
+    ...
+</storage_configuration>
+```
+
+In given example, the `hdd_in_order` policy implements the [round-robin](https://en.wikipedia.org/wiki/Round-robin_scheduling) approach. Thus this policy defines only one volume (`single`), the data parts are stored on all its disks in circular order. Such policy can be quite useful if there are several similar disks are mounted to the system, but RAID is not configured. Keep in mind that each individual disk drive is not reliable and you might want to compensate it with replication factor of 3 or more.
+
+If there are different kinds of disks available in the system, `moving_from_ssd_to_hdd` policy can be used instead. The volume `hot` consists of an SSD disk (`fast_ssd`), and the maximum size of a part that can be stored on this volume is 1GB. All the parts with the size larger than 1GB will be stored directly on the `cold` volume, which contains an HDD disk `disk1`.
+Also, once the disk `fast_ssd` gets filled by more than 80%, data will be transferred to the `disk1` by a background process.
+
+The order of volume enumeration within a storage policy is important. Once a volume is overfilled, data are moved to the next one. The order of disk enumeration is important as well because data are stored on them in turns.
+
+When creating a table, one can apply one of the configured storage policies to it:
+
+``` sql
+CREATE TABLE table_with_non_default_policy (
+    EventDate Date,
+    OrderID UInt64,
+    BannerID UInt64,
+    SearchPhrase String
+) ENGINE = MergeTree
+ORDER BY (OrderID, BannerID)
+PARTITION BY toYYYYMM(EventDate)
+SETTINGS storage_policy = 'moving_from_ssd_to_hdd'
+```
+
+The `default` storage policy implies using only one volume, which consists of only one disk given in `<path>`.
+You could change storage policy after table creation with [ALTER TABLE ... MODIFY SETTING] query, new policy should include all old disks and volumes with same names.
+
+The number of threads performing background moves of data parts can be changed by [background_move_pool_size](../../../operations/settings/settings.md#background_move_pool_size) setting.
+
+### Details {#details}
+
+In the case of `MergeTree` tables, data is getting to disk in different ways:
+
+-   As a result of an insert (`INSERT` query).
+-   During background merges and [mutations](../../../sql-reference/statements/alter/index.md#alter-mutations).
+-   When downloading from another replica.
+-   As a result of partition freezing [ALTER TABLE … FREEZE PARTITION](../../../sql-reference/statements/alter/partition.md#alter_freeze-partition).
+
+In all these cases except for mutations and partition freezing, a part is stored on a volume and a disk according to the given storage policy:
+
+1.  The first volume (in the order of definition) that has enough disk space for storing a part (`unreserved_space > current_part_size`) and allows for storing parts of a given size (`max_data_part_size_bytes > current_part_size`) is chosen.
+2.  Within this volume, that disk is chosen that follows the one, which was used for storing the previous chunk of data, and that has free space more than the part size (`unreserved_space - keep_free_space_bytes > current_part_size`).
+
+Under the hood, mutations and partition freezing make use of [hard links](https://en.wikipedia.org/wiki/Hard_link). Hard links between different disks are not supported, therefore in such cases the resulting parts are stored on the same disks as the initial ones.
+
+In the background, parts are moved between volumes on the basis of the amount of free space (`move_factor` parameter) according to the order the volumes are declared in the configuration file.
+Data is never transferred from the last one and into the first one. One may use system tables [system.part_log](../../../operations/system-tables/part_log.md#system_tables-part-log) (field `type = MOVE_PART`) and [system.parts](../../../operations/system-tables/parts.md#system_tables-parts) (fields `path` and `disk`) to monitor background moves. Also, the detailed information can be found in server logs.
+
+User can force moving a part or a partition from one volume to another using the query [ALTER TABLE … MOVE PART\|PARTITION … TO VOLUME\|DISK …](../../../sql-reference/statements/alter/partition.md#alter_move-partition), all the restrictions for background operations are taken into account. The query initiates a move on its own and does not wait for background operations to be completed. User will get an error message if not enough free space is available or if any of the required conditions are not met.
+
+Moving data does not interfere with data replication. Therefore, different storage policies can be specified for the same table on different replicas.
+
+After the completion of background merges and mutations, old parts are removed only after a certain amount of time (`old_parts_lifetime`).
+During this time, they are not moved to other volumes or disks. Therefore, until the parts are finally removed, they are still taken into account for evaluation of the occupied disk space.
+
+User can assign new big parts to different disks of a [JBOD](https://en.wikipedia.org/wiki/Non-RAID_drive_architectures) volume in a balanced way using the [min_bytes_to_rebalance_partition_over_jbod](../../../operations/settings/merge-tree-settings.md#min-bytes-to-rebalance-partition-over-jbod) setting.
+
+## Using S3 for Data Storage {#table_engine-mergetree-s3}
+
+`MergeTree` family table engines can store data to [S3](https://aws.amazon.com/s3/) using a disk with type `s3`.
+
+This feature is under development and not ready for production. There are known drawbacks such as very low performance.
+
+Configuration markup:
+``` xml
+<storage_configuration>
+    ...
+    <disks>
+        <s3>
+            <type>s3</type>
+            <endpoint>https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/root-path/</endpoint>
+            <access_key_id>your_access_key_id</access_key_id>
+            <secret_access_key>your_secret_access_key</secret_access_key>
+            <region></region>
+            <server_side_encryption_customer_key_base64>your_base64_encoded_customer_key</server_side_encryption_customer_key_base64>
+            <proxy>
+                <uri>http://proxy1</uri>
+                <uri>http://proxy2</uri>
+            </proxy>
+            <connect_timeout_ms>10000</connect_timeout_ms>
+            <request_timeout_ms>5000</request_timeout_ms>
+            <retry_attempts>10</retry_attempts>
+            <single_read_retries>4</single_read_retries>
+            <min_bytes_for_seek>1000</min_bytes_for_seek>
+            <metadata_path>/var/lib/clickhouse/disks/s3/</metadata_path>
+            <cache_enabled>true</cache_enabled>
+            <cache_path>/var/lib/clickhouse/disks/s3/cache/</cache_path>
+            <skip_access_check>false</skip_access_check>
+        </s3>
+    </disks>
+    ...
+</storage_configuration>
+```
+
+Required parameters:
+
+-   `endpoint` — S3 endpoint URL in `path` or `virtual hosted` [styles](https://docs.aws.amazon.com/AmazonS3/latest/dev/VirtualHosting.html). Endpoint URL should contain a bucket and root path to store data.
+-   `access_key_id` — S3 access key id.
+-   `secret_access_key` — S3 secret access key.
+
+Optional parameters:
+
+-   `region` — S3 region name.
+-   `use_environment_credentials` — Reads AWS credentials from the Environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY and AWS_SESSION_TOKEN if they exist. Default value is `false`.
+-   `use_insecure_imds_request` — If set to `true`, S3 client will use insecure IMDS request while obtaining credentials from Amazon EC2 metadata. Default value is `false`.
+-   `proxy` — Proxy configuration for S3 endpoint. Each `uri` element inside `proxy` block should contain a proxy URL.
+-   `connect_timeout_ms` — Socket connect timeout in milliseconds. Default value is `10 seconds`.
+-   `request_timeout_ms` — Request timeout in milliseconds. Default value is `5 seconds`.
+-   `retry_attempts` — Number of retry attempts in case of failed request. Default value is `10`.
+-   `single_read_retries` — Number of retry attempts in case of connection drop during read. Default value is `4`.
+-   `min_bytes_for_seek` — Minimal number of bytes to use seek operation instead of sequential read. Default value is `1 Mb`.
+-   `metadata_path` — Path on local FS to store metadata files for S3. Default value is `/var/lib/clickhouse/disks/<disk_name>/`.
+-   `cache_enabled` — Allows to cache mark and index files on local FS. Default value is `true`.
+-   `cache_path` — Path on local FS where to store cached mark and index files. Default value is `/var/lib/clickhouse/disks/<disk_name>/cache/`.
+-   `skip_access_check` — If true, disk access checks will not be performed on disk start-up. Default value is `false`.
+-   `server_side_encryption_customer_key_base64` — If specified, required headers for accessing S3 objects with SSE-C encryption will be set.
+
+S3 disk can be configured as `main` or `cold` storage:
+``` xml
+<storage_configuration>
+    ...
+    <disks>
+        <s3>
+            <type>s3</type>
+            <endpoint>https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/root-path/</endpoint>
+            <access_key_id>your_access_key_id</access_key_id>
+            <secret_access_key>your_secret_access_key</secret_access_key>
+        </s3>
+    </disks>
+    <policies>
+        <s3_main>
+            <volumes>
+                <main>
+                    <disk>s3</disk>
+                </main>
+            </volumes>
+        </s3_main>
+        <s3_cold>
+            <volumes>
+                <main>
+                    <disk>default</disk>
+                </main>
+                <external>
+                    <disk>s3</disk>
+                </external>
+            </volumes>
+            <move_factor>0.2</move_factor>
+        </s3_cold>
+    </policies>
+    ...
+</storage_configuration>
+```
+
+In case of `cold` option a data can be moved to S3 if local disk free size will be smaller than `move_factor * disk_size` or by TTL move rule.
+
+## Using Azure Blob Storage for Data Storage {#table_engine-mergetree-azure-blob-storage}
+
+`MergeTree` family table engines can store data to [Azure Blob Storage](https://azure.microsoft.com/en-us/services/storage/blobs/) using a disk with type `azure_blob_storage`.
+
+As of February 2022, this feature is still a fresh addition, so expect that some Azure Blob Storage functionalities might be unimplemented.
+
+Configuration markup:
+``` xml
+<storage_configuration>
+    ...
+    <disks>
+        <blob_storage_disk>
+            <type>azure_blob_storage</type>
+            <storage_account_url>http://account.blob.core.windows.net</storage_account_url>
+            <container_name>container</container_name>
+            <account_name>account</account_name>
+            <account_key>pass123</account_key>
+            <metadata_path>/var/lib/clickhouse/disks/blob_storage_disk/</metadata_path>
+            <cache_enabled>true</cache_enabled>
+            <cache_path>/var/lib/clickhouse/disks/blob_storage_disk/cache/</cache_path>
+            <skip_access_check>false</skip_access_check>
+        </blob_storage_disk>
+    </disks>
+    ...
+</storage_configuration>
+```
+
+Connection parameters:
+* `storage_account_url` - **Required**, Azure Blob Storage account URL, like `http://account.blob.core.windows.net` or `http://azurite1:10000/devstoreaccount1`.
+* `container_name` - Target container name, defaults to `default-container`.
+* `container_already_exists` - If set to `false`, a new container `container_name` is created in the storage account, if set to `true`, disk connects to the container directly, and if left unset, disk connects to the account, checks if the container `container_name` exists, and creates it if it doesn't exist yet.
+
+Authentication parameters (the disk will try all available methods **and** Managed Identity Credential):
+* `connection_string` - For authentication using a connection string.
+* `account_name` and `account_key` - For authentication using Shared Key.
+
+Limit parameters (mainly for internal usage):
+* `max_single_part_upload_size` - Limits the size of a single block upload to Blob Storage.
+* `min_bytes_for_seek` - Limits the size of a seekable region.
+* `max_single_read_retries` - Limits the number of attempts to read a chunk of data from Blob Storage.
+* `max_single_download_retries` - Limits the number of attempts to download a readable buffer from Blob Storage.
+* `thread_pool_size` - Limits the number of threads with which `IDiskRemote` is instantiated.
+
+Other parameters:
+* `metadata_path` - Path on local FS to store metadata files for Blob Storage. Default value is `/var/lib/clickhouse/disks/<disk_name>/`.
+* `cache_enabled` - Allows to cache mark and index files on local FS. Default value is `true`.
+* `cache_path` - Path on local FS where to store cached mark and index files. Default value is `/var/lib/clickhouse/disks/<disk_name>/cache/`.
+* `skip_access_check` - If true, disk access checks will not be performed on disk start-up. Default value is `false`.
+
+Examples of working configurations can be found in integration tests directory (see e.g. [test_merge_tree_azure_blob_storage](https://github.com/ClickHouse/ClickHouse/blob/master/tests/integration/test_merge_tree_azure_blob_storage/configs/config.d/storage_conf.xml) or [test_azure_blob_storage_zero_copy_replication](https://github.com/ClickHouse/ClickHouse/blob/master/tests/integration/test_azure_blob_storage_zero_copy_replication/configs/config.d/storage_conf.xml)).
+
+## Virtual Columns {#virtual-columns}
+
+-   `_part` — Name of a part.
+-   `_part_index` — Sequential index of the part in the query result.
+-   `_partition_id` — Name of a partition.
+-   `_part_uuid` — Unique part identifier (if enabled MergeTree setting `assign_part_uuids`).
+-   `_partition_value` — Values (a tuple) of a `partition by` expression.
+-   `_sample_factor` — Sample factor (from the query).
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/replacingmergetree.md b/docs/en/reference/engines/table-engines/mergetree-family/replacingmergetree.md
new file mode 100644
index 00000000000..47651527f99
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/mergetree-family/replacingmergetree.md
@@ -0,0 +1,70 @@
+---
+sidebar_position: 40
+sidebar_label:  ReplacingMergeTree
+---
+
+# ReplacingMergeTree {#replacingmergetree}
+
+The engine differs from [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md#table_engines-mergetree) in that it removes duplicate entries with the same [sorting key](../../../engines/table-engines/mergetree-family/mergetree.md) value (`ORDER BY` table section, not `PRIMARY KEY`).
+
+Data deduplication occurs only during a merge. Merging occurs in the background at an unknown time, so you can’t plan for it. Some of the data may remain unprocessed. Although you can run an unscheduled merge using the `OPTIMIZE` query, do not count on using it, because the `OPTIMIZE` query will read and write a large amount of data.
+
+Thus, `ReplacingMergeTree` is suitable for clearing out duplicate data in the background in order to save space, but it does not guarantee the absence of duplicates.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = ReplacingMergeTree([ver])
+[PARTITION BY expr]
+[ORDER BY expr]
+[PRIMARY KEY expr]
+[SAMPLE BY expr]
+[SETTINGS name=value, ...]
+```
+
+For a description of request parameters, see [statement description](../../../sql-reference/statements/create/table.md).
+
+:::warning
+Uniqueness of rows is determined by the `ORDER BY` table section, not `PRIMARY KEY`.
+:::
+
+**ReplacingMergeTree Parameters**
+
+-   `ver` — column with the version number. Type `UInt*`, `Date`, `DateTime` or `DateTime64`. Optional parameter.
+
+    When merging, `ReplacingMergeTree` from all the rows with the same sorting key leaves only one:
+
+    -   The last in the selection, if `ver` not set. A selection is a set of rows in a set of parts participating in the merge. The most recently created part (the last insert) will be the last one in the selection. Thus, after deduplication, the very last row from the most recent insert will remain for each unique sorting key.
+    -   With the maximum version, if `ver` specified.
+
+**Query clauses**
+
+When creating a `ReplacingMergeTree` table the same [clauses](../../../engines/table-engines/mergetree-family/mergetree.md) are required, as when creating a `MergeTree` table.
+
+<details markdown="1">
+
+<summary>Deprecated Method for Creating a Table</summary>
+
+:::warning
+Do not use this method in new projects and, if possible, switch old projects to the method described above.
+:::
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE [=] ReplacingMergeTree(date-column [, sampling_expression], (primary, key), index_granularity, [ver])
+```
+
+All of the parameters excepting `ver` have the same meaning as in `MergeTree`.
+
+-   `ver` - column with the version. Optional parameter. For a description, see the text above.
+
+</details>
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/replication.md b/docs/en/reference/engines/table-engines/mergetree-family/replication.md
new file mode 100644
index 00000000000..67c503854a9
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/mergetree-family/replication.md
@@ -0,0 +1,295 @@
+---
+sidebar_position: 20
+sidebar_label: Data Replication
+---
+
+# Data Replication {#table_engines-replication}
+
+Replication is only supported for tables in the MergeTree family:
+
+-   ReplicatedMergeTree
+-   ReplicatedSummingMergeTree
+-   ReplicatedReplacingMergeTree
+-   ReplicatedAggregatingMergeTree
+-   ReplicatedCollapsingMergeTree
+-   ReplicatedVersionedCollapsingMergeTree
+-   ReplicatedGraphiteMergeTree
+
+Replication works at the level of an individual table, not the entire server. A server can store both replicated and non-replicated tables at the same time.
+
+Replication does not depend on sharding. Each shard has its own independent replication.
+
+Compressed data for `INSERT` and `ALTER` queries is replicated (for more information, see the documentation for [ALTER](../../../sql-reference/statements/alter/index.md#query_language_queries_alter)).
+
+`CREATE`, `DROP`, `ATTACH`, `DETACH` and `RENAME` queries are executed on a single server and are not replicated:
+
+-   The `CREATE TABLE` query creates a new replicatable table on the server where the query is run. If this table already exists on other servers, it adds a new replica.
+-   The `DROP TABLE` query deletes the replica located on the server where the query is run.
+-   The `RENAME` query renames the table on one of the replicas. In other words, replicated tables can have different names on different replicas.
+
+ClickHouse uses [Apache ZooKeeper](https://zookeeper.apache.org) for storing replicas meta information. Use ZooKeeper version 3.4.5 or newer.
+
+To use replication, set parameters in the [zookeeper](../../../operations/server-configuration-parameters/settings.md#server-settings_zookeeper) server configuration section.
+
+:::warning
+Don’t neglect the security setting. ClickHouse supports the `digest` [ACL scheme](https://zookeeper.apache.org/doc/current/zookeeperProgrammers.html#sc_ZooKeeperAccessControl) of the ZooKeeper security subsystem.
+:::
+
+Example of setting the addresses of the ZooKeeper cluster:
+
+``` xml
+<zookeeper>
+    <node>
+        <host>example1</host>
+        <port>2181</port>
+    </node>
+    <node>
+        <host>example2</host>
+        <port>2181</port>
+    </node>
+    <node>
+        <host>example3</host>
+        <port>2181</port>
+    </node>
+</zookeeper>
+```
+
+ClickHouse also supports to store replicas meta information in the auxiliary ZooKeeper cluster by providing ZooKeeper cluster name and path as engine arguments.
+In other word, it supports to store the metadata of differnt tables in different ZooKeeper clusters.
+
+Example of setting the addresses of the auxiliary ZooKeeper cluster:
+
+``` xml
+<auxiliary_zookeepers>
+    <zookeeper2>
+        <node>
+            <host>example_2_1</host>
+            <port>2181</port>
+        </node>
+        <node>
+            <host>example_2_2</host>
+            <port>2181</port>
+        </node>
+        <node>
+            <host>example_2_3</host>
+            <port>2181</port>
+        </node>
+    </zookeeper2>
+    <zookeeper3>
+        <node>
+            <host>example_3_1</host>
+            <port>2181</port>
+        </node>
+    </zookeeper3>
+</auxiliary_zookeepers>
+```
+
+To store table datameta in a auxiliary ZooKeeper cluster instead of default ZooKeeper cluster, we can use the SQL to create table with
+ReplicatedMergeTree engine as follow:
+
+```
+CREATE TABLE table_name ( ... ) ENGINE = ReplicatedMergeTree('zookeeper_name_configured_in_auxiliary_zookeepers:path', 'replica_name') ...
+```
+You can specify any existing ZooKeeper cluster and the system will use a directory on it for its own data (the directory is specified when creating a replicatable table).
+
+If ZooKeeper isn’t set in the config file, you can’t create replicated tables, and any existing replicated tables will be read-only.
+
+ZooKeeper is not used in `SELECT` queries because replication does not affect the performance of `SELECT` and queries run just as fast as they do for non-replicated tables. When querying distributed replicated tables, ClickHouse behavior is controlled by the settings [max_replica_delay_for_distributed_queries](../../../operations/settings/settings.md#settings-max_replica_delay_for_distributed_queries) and [fallback_to_stale_replicas_for_distributed_queries](../../../operations/settings/settings.md#settings-fallback_to_stale_replicas_for_distributed_queries).
+
+For each `INSERT` query, approximately ten entries are added to ZooKeeper through several transactions. (To be more precise, this is for each inserted block of data; an INSERT query contains one block or one block per `max_insert_block_size = 1048576` rows.) This leads to slightly longer latencies for `INSERT` compared to non-replicated tables. But if you follow the recommendations to insert data in batches of no more than one `INSERT` per second, it does not create any problems. The entire ClickHouse cluster used for coordinating one ZooKeeper cluster has a total of several hundred `INSERTs` per second. The throughput on data inserts (the number of rows per second) is just as high as for non-replicated data.
+
+For very large clusters, you can use different ZooKeeper clusters for different shards. However, from our experience this has not proven necessary based on production clusters with approximately 300 servers.
+
+Replication is asynchronous and multi-master. `INSERT` queries (as well as `ALTER`) can be sent to any available server. Data is inserted on the server where the query is run, and then it is copied to the other servers. Because it is asynchronous, recently inserted data appears on the other replicas with some latency. If part of the replicas are not available, the data is written when they become available. If a replica is available, the latency is the amount of time it takes to transfer the block of compressed data over the network. The number of threads performing background tasks for replicated tables can be set by [background_schedule_pool_size](../../../operations/settings/settings.md#background_schedule_pool_size) setting.
+
+`ReplicatedMergeTree` engine uses a separate thread pool for replicated fetches. Size of the pool is limited by the [background_fetches_pool_size](../../../operations/settings/settings.md#background_fetches_pool_size) setting which can be tuned with a server restart.
+
+By default, an INSERT query waits for confirmation of writing the data from only one replica. If the data was successfully written to only one replica and the server with this replica ceases to exist, the stored data will be lost. To enable getting confirmation of data writes from multiple replicas, use the `insert_quorum` option.
+
+Each block of data is written atomically. The INSERT query is divided into blocks up to `max_insert_block_size = 1048576` rows. In other words, if the `INSERT` query has less than 1048576 rows, it is made atomically.
+
+Data blocks are deduplicated. For multiple writes of the same data block (data blocks of the same size containing the same rows in the same order), the block is only written once. The reason for this is in case of network failures when the client application does not know if the data was written to the DB, so the `INSERT` query can simply be repeated. It does not matter which replica INSERTs were sent to with identical data. `INSERTs` are idempotent. Deduplication parameters are controlled by [merge_tree](../../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-merge_tree) server settings.
+
+During replication, only the source data to insert is transferred over the network. Further data transformation (merging) is coordinated and performed on all the replicas in the same way. This minimizes network usage, which means that replication works well when replicas reside in different datacenters. (Note that duplicating data in different datacenters is the main goal of replication.)
+
+You can have any number of replicas of the same data. Based on our experiences, a relatively reliable and convenient solution could use double replication in production, with each server using RAID-5 or RAID-6 (and RAID-10 in some cases). 
+
+The system monitors data synchronicity on replicas and is able to recover after a failure. Failover is automatic (for small differences in data) or semi-automatic (when data differs too much, which may indicate a configuration error).
+
+## Creating Replicated Tables {#creating-replicated-tables}
+
+The `Replicated` prefix is added to the table engine name. For example:`ReplicatedMergeTree`.
+
+**Replicated\*MergeTree parameters**
+
+-   `zoo_path` — The path to the table in ZooKeeper.
+-   `replica_name` — The replica name in ZooKeeper.
+-   `other_parameters` — Parameters of an engine which is used for creating the replicated version, for example, version in `ReplacingMergeTree`.
+
+Example:
+
+``` sql
+CREATE TABLE table_name
+(
+    EventDate DateTime,
+    CounterID UInt32,
+    UserID UInt32,
+    ver UInt16
+) ENGINE = ReplicatedReplacingMergeTree('/clickhouse/tables/{layer}-{shard}/table_name', '{replica}', ver)
+PARTITION BY toYYYYMM(EventDate)
+ORDER BY (CounterID, EventDate, intHash32(UserID))
+SAMPLE BY intHash32(UserID);
+```
+
+<details markdown="1">
+
+<summary>Example in deprecated syntax</summary>
+
+``` sql
+CREATE TABLE table_name
+(
+    EventDate DateTime,
+    CounterID UInt32,
+    UserID UInt32
+) ENGINE = ReplicatedMergeTree('/clickhouse/tables/{layer}-{shard}/table_name', '{replica}', EventDate, intHash32(UserID), (CounterID, EventDate, intHash32(UserID), EventTime), 8192);
+```
+
+</details>
+
+As the example shows, these parameters can contain substitutions in curly brackets. The substituted values are taken from the [macros](../../../operations/server-configuration-parameters/settings.md#macros) section of the configuration file.
+
+Example:
+
+``` xml
+<macros>
+    <layer>05</layer>
+    <shard>02</shard>
+    <replica>example05-02-1</replica>
+</macros>
+```
+
+The path to the table in ZooKeeper should be unique for each replicated table. Tables on different shards should have different paths.
+In this case, the path consists of the following parts:
+
+`/clickhouse/tables/` is the common prefix. We recommend using exactly this one.
+
+`{layer}-{shard}` is the shard identifier. In this example it consists of two parts, since the example cluster uses bi-level sharding. For most tasks, you can leave just the {shard} substitution, which will be expanded to the shard identifier.
+
+`table_name` is the name of the node for the table in ZooKeeper. It is a good idea to make it the same as the table name. It is defined explicitly, because in contrast to the table name, it does not change after a RENAME query.
+*HINT*: you could add a database name in front of `table_name` as well. E.g. `db_name.table_name`
+
+The two built-in substitutions `{database}` and `{table}` can be used, they expand into the table name and the database name respectively (unless these macros are defined in the `macros` section). So the zookeeper path can be specified as `'/clickhouse/tables/{layer}-{shard}/{database}/{table}'`.
+Be careful with table renames when using these built-in substitutions. The path in Zookeeper cannot be changed, and when the table is renamed, the macros will expand into a different path, the table will refer to a path that does not exist in Zookeeper, and will go into read-only mode.
+
+The replica name identifies different replicas of the same table. You can use the server name for this, as in the example. The name only needs to be unique within each shard.
+
+You can define the parameters explicitly instead of using substitutions. This might be convenient for testing and for configuring small clusters. However, you can’t use distributed DDL queries (`ON CLUSTER`) in this case.
+
+When working with large clusters, we recommend using substitutions because they reduce the probability of error.
+
+You can specify default arguments for `Replicated` table engine in the server configuration file. For instance:
+
+```xml
+<default_replica_path>/clickhouse/tables/{shard}/{database}/{table}</default_replica_path>
+<default_replica_name>{replica}</default_replica_name>
+```
+
+In this case, you can omit arguments when creating tables:
+
+``` sql
+CREATE TABLE table_name (
+	x UInt32
+) ENGINE = ReplicatedMergeTree
+ORDER BY x;
+```
+
+It is equivalent to:
+
+``` sql
+CREATE TABLE table_name (
+	x UInt32
+) ENGINE = ReplicatedMergeTree('/clickhouse/tables/{shard}/{database}/table_name', '{replica}')
+ORDER BY x;
+```
+
+Run the `CREATE TABLE` query on each replica. This query creates a new replicated table, or adds a new replica to an existing one.
+
+If you add a new replica after the table already contains some data on other replicas, the data will be copied from the other replicas to the new one after running the query. In other words, the new replica syncs itself with the others.
+
+To delete a replica, run `DROP TABLE`. However, only one replica is deleted – the one that resides on the server where you run the query.
+
+## Recovery After Failures {#recovery-after-failures}
+
+If ZooKeeper is unavailable when a server starts, replicated tables switch to read-only mode. The system periodically attempts to connect to ZooKeeper.
+
+If ZooKeeper is unavailable during an `INSERT`, or an error occurs when interacting with ZooKeeper, an exception is thrown.
+
+After connecting to ZooKeeper, the system checks whether the set of data in the local file system matches the expected set of data (ZooKeeper stores this information). If there are minor inconsistencies, the system resolves them by syncing data with the replicas.
+
+If the system detects broken data parts (with the wrong size of files) or unrecognized parts (parts written to the file system but not recorded in ZooKeeper), it moves them to the `detached` subdirectory (they are not deleted). Any missing parts are copied from the replicas.
+
+Note that ClickHouse does not perform any destructive actions such as automatically deleting a large amount of data.
+
+When the server starts (or establishes a new session with ZooKeeper), it only checks the quantity and sizes of all files. If the file sizes match but bytes have been changed somewhere in the middle, this is not detected immediately, but only when attempting to read the data for a `SELECT` query. The query throws an exception about a non-matching checksum or size of a compressed block. In this case, data parts are added to the verification queue and copied from the replicas if necessary.
+
+If the local set of data differs too much from the expected one, a safety mechanism is triggered. The server enters this in the log and refuses to launch. The reason for this is that this case may indicate a configuration error, such as if a replica on a shard was accidentally configured like a replica on a different shard. However, the thresholds for this mechanism are set fairly low, and this situation might occur during normal failure recovery. In this case, data is restored semi-automatically - by “pushing a button”.
+
+To start recovery, create the node `/path_to_table/replica_name/flags/force_restore_data` in ZooKeeper with any content, or run the command to restore all replicated tables:
+
+``` bash
+sudo -u clickhouse touch /var/lib/clickhouse/flags/force_restore_data
+```
+
+Then restart the server. On start, the server deletes these flags and starts recovery.
+
+## Recovery After Complete Data Loss {#recovery-after-complete-data-loss}
+
+If all data and metadata disappeared from one of the servers, follow these steps for recovery:
+
+1.  Install ClickHouse on the server. Define substitutions correctly in the config file that contains the shard identifier and replicas, if you use them.
+2.  If you had unreplicated tables that must be manually duplicated on the servers, copy their data from a replica (in the directory `/var/lib/clickhouse/data/db_name/table_name/`).
+3.  Copy table definitions located in `/var/lib/clickhouse/metadata/` from a replica. If a shard or replica identifier is defined explicitly in the table definitions, correct it so that it corresponds to this replica. (Alternatively, start the server and make all the `ATTACH TABLE` queries that should have been in the .sql files in `/var/lib/clickhouse/metadata/`.)
+4.  To start recovery, create the ZooKeeper node `/path_to_table/replica_name/flags/force_restore_data` with any content, or run the command to restore all replicated tables: `sudo -u clickhouse touch /var/lib/clickhouse/flags/force_restore_data`
+
+Then start the server (restart, if it is already running). Data will be downloaded from replicas.
+
+An alternative recovery option is to delete information about the lost replica from ZooKeeper (`/path_to_table/replica_name`), then create the replica again as described in “[Creating replicated tables](#creating-replicated-tables)”.
+
+There is no restriction on network bandwidth during recovery. Keep this in mind if you are restoring many replicas at once.
+
+## Converting from MergeTree to ReplicatedMergeTree {#converting-from-mergetree-to-replicatedmergetree}
+
+We use the term `MergeTree` to refer to all table engines in the `MergeTree family`, the same as for `ReplicatedMergeTree`.
+
+If you had a `MergeTree` table that was manually replicated, you can convert it to a replicated table. You might need to do this if you have already collected a large amount of data in a `MergeTree` table and now you want to enable replication.
+
+If the data differs on various replicas, first sync it, or delete this data on all the replicas except one.
+
+Rename the existing MergeTree table, then create a `ReplicatedMergeTree` table with the old name.
+Move the data from the old table to the `detached` subdirectory inside the directory with the new table data (`/var/lib/clickhouse/data/db_name/table_name/`).
+Then run `ALTER TABLE ATTACH PARTITION` on one of the replicas to add these data parts to the working set.
+
+## Converting from ReplicatedMergeTree to MergeTree {#converting-from-replicatedmergetree-to-mergetree}
+
+Create a MergeTree table with a different name. Move all the data from the directory with the `ReplicatedMergeTree` table data to the new table’s data directory. Then delete the `ReplicatedMergeTree` table and restart the server.
+
+If you want to get rid of a `ReplicatedMergeTree` table without launching the server:
+
+-   Delete the corresponding `.sql` file in the metadata directory (`/var/lib/clickhouse/metadata/`).
+-   Delete the corresponding path in ZooKeeper (`/path_to_table/replica_name`).
+
+After this, you can launch the server, create a `MergeTree` table, move the data to its directory, and then restart the server.
+
+## Recovery When Metadata in the Zookeeper Cluster Is Lost or Damaged {#recovery-when-metadata-in-the-zookeeper-cluster-is-lost-or-damaged}
+
+If the data in ZooKeeper was lost or damaged, you can save data by moving it to an unreplicated table as described above.
+
+**See Also**
+
+-   [background_schedule_pool_size](../../../operations/settings/settings.md#background_schedule_pool_size)
+-   [background_fetches_pool_size](../../../operations/settings/settings.md#background_fetches_pool_size)
+-   [execute_merges_on_single_replica_time_threshold](../../../operations/settings/settings.md#execute-merges-on-single-replica-time-threshold)
+-   [max_replicated_fetches_network_bandwidth](../../../operations/settings/merge-tree-settings.md#max_replicated_fetches_network_bandwidth)
+-   [max_replicated_sends_network_bandwidth](../../../operations/settings/merge-tree-settings.md#max_replicated_sends_network_bandwidth)
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/replication/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/summingmergetree.md b/docs/en/reference/engines/table-engines/mergetree-family/summingmergetree.md
new file mode 100644
index 00000000000..5d180782ed3
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/mergetree-family/summingmergetree.md
@@ -0,0 +1,140 @@
+---
+sidebar_position: 50
+sidebar_label:  SummingMergeTree
+---
+
+# SummingMergeTree {#summingmergetree}
+
+The engine inherits from [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md#table_engines-mergetree). The difference is that when merging data parts for `SummingMergeTree` tables ClickHouse replaces all the rows with the same primary key (or more accurately, with the same [sorting key](../../../engines/table-engines/mergetree-family/mergetree.md)) with one row which contains summarized values for the columns with the numeric data type. If the sorting key is composed in a way that a single key value corresponds to large number of rows, this significantly reduces storage volume and speeds up data selection.
+
+We recommend using the engine together with `MergeTree`. Store complete data in `MergeTree` table, and use `SummingMergeTree` for aggregated data storing, for example, when preparing reports. Such an approach will prevent you from losing valuable data due to an incorrectly composed primary key.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = SummingMergeTree([columns])
+[PARTITION BY expr]
+[ORDER BY expr]
+[SAMPLE BY expr]
+[SETTINGS name=value, ...]
+```
+
+For a description of request parameters, see [request description](../../../sql-reference/statements/create/table.md).
+
+**Parameters of SummingMergeTree**
+
+-   `columns` - a tuple with the names of columns where values will be summarized. Optional parameter.
+    The columns must be of a numeric type and must not be in the primary key.
+
+    If `columns` not specified, ClickHouse summarizes the values in all columns with a numeric data type that are not in the primary key.
+
+**Query clauses**
+
+When creating a `SummingMergeTree` table the same [clauses](../../../engines/table-engines/mergetree-family/mergetree.md) are required, as when creating a `MergeTree` table.
+
+<details markdown="1">
+
+<summary>Deprecated Method for Creating a Table</summary>
+
+:::warning
+Do not use this method in new projects and, if possible, switch the old projects to the method described above.
+:::
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE [=] SummingMergeTree(date-column [, sampling_expression], (primary, key), index_granularity, [columns])
+```
+
+All of the parameters excepting `columns` have the same meaning as in `MergeTree`.
+
+-   `columns` — tuple with names of columns values of which will be summarized. Optional parameter. For a description, see the text above.
+
+</details>
+
+## Usage Example {#usage-example}
+
+Consider the following table:
+
+``` sql
+CREATE TABLE summtt
+(
+    key UInt32,
+    value UInt32
+)
+ENGINE = SummingMergeTree()
+ORDER BY key
+```
+
+Insert data to it:
+
+``` sql
+INSERT INTO summtt Values(1,1),(1,2),(2,1)
+```
+
+ClickHouse may sum all the rows not completely ([see below](#data-processing)), so we use an aggregate function `sum` and `GROUP BY` clause in the query.
+
+``` sql
+SELECT key, sum(value) FROM summtt GROUP BY key
+```
+
+``` text
+┌─key─┬─sum(value)─┐
+│   2 │          1 │
+│   1 │          3 │
+└─────┴────────────┘
+```
+
+## Data Processing {#data-processing}
+
+When data are inserted into a table, they are saved as-is. ClickHouse merges the inserted parts of data periodically and this is when rows with the same primary key are summed and replaced with one for each resulting part of data.
+
+ClickHouse can merge the data parts so that different resulting parts of data can consist rows with the same primary key, i.e. the summation will be incomplete. Therefore (`SELECT`) an aggregate function [sum()](../../../sql-reference/aggregate-functions/reference/sum.md#agg_function-sum) and `GROUP BY` clause should be used in a query as described in the example above.
+
+### Common Rules for Summation {#common-rules-for-summation}
+
+The values in the columns with the numeric data type are summarized. The set of columns is defined by the parameter `columns`.
+
+If the values were 0 in all of the columns for summation, the row is deleted.
+
+If column is not in the primary key and is not summarized, an arbitrary value is selected from the existing ones.
+
+The values are not summarized for columns in the primary key.
+
+### The Summation in the Aggregatefunction Columns {#the-summation-in-the-aggregatefunction-columns}
+
+For columns of [AggregateFunction type](../../../sql-reference/data-types/aggregatefunction.md) ClickHouse behaves as [AggregatingMergeTree](../../../engines/table-engines/mergetree-family/aggregatingmergetree.md) engine aggregating according to the function.
+
+### Nested Structures {#nested-structures}
+
+Table can have nested data structures that are processed in a special way.
+
+If the name of a nested table ends with `Map` and it contains at least two columns that meet the following criteria:
+
+-   the first column is numeric `(*Int*, Date, DateTime)` or a string `(String, FixedString)`, let’s call it `key`,
+-   the other columns are arithmetic `(*Int*, Float32/64)`, let’s call it `(values...)`,
+
+then this nested table is interpreted as a mapping of `key => (values...)`, and when merging its rows, the elements of two data sets are merged by `key` with a summation of the corresponding `(values...)`.
+
+Examples:
+
+``` text
+[(1, 100)] + [(2, 150)] -> [(1, 100), (2, 150)]
+[(1, 100)] + [(1, 150)] -> [(1, 250)]
+[(1, 100)] + [(1, 150), (2, 150)] -> [(1, 250), (2, 150)]
+[(1, 100), (2, 150)] + [(1, -100)] -> [(2, 150)]
+```
+
+When requesting data, use the [sumMap(key, value)](../../../sql-reference/aggregate-functions/reference/summap.md) function for aggregation of `Map`.
+
+For nested data structure, you do not need to specify its columns in the tuple of columns for summation.
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/summingmergetree/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/mergetree-family/versionedcollapsingmergetree.md b/docs/en/reference/engines/table-engines/mergetree-family/versionedcollapsingmergetree.md
new file mode 100644
index 00000000000..77cf192dcda
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/mergetree-family/versionedcollapsingmergetree.md
@@ -0,0 +1,237 @@
+---
+sidebar_position: 80
+sidebar_label:  VersionedCollapsingMergeTree
+---
+
+# VersionedCollapsingMergeTree {#versionedcollapsingmergetree}
+
+This engine:
+
+-   Allows quick writing of object states that are continually changing.
+-   Deletes old object states in the background. This significantly reduces the volume of storage.
+
+See the section [Collapsing](#table_engines_versionedcollapsingmergetree) for details.
+
+The engine inherits from [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md#table_engines-mergetree) and adds the logic for collapsing rows to the algorithm for merging data parts. `VersionedCollapsingMergeTree` serves the same purpose as [CollapsingMergeTree](../../../engines/table-engines/mergetree-family/collapsingmergetree.md) but uses a different collapsing algorithm that allows inserting the data in any order with multiple threads. In particular, the `Version` column helps to collapse the rows properly even if they are inserted in the wrong order. In contrast, `CollapsingMergeTree` allows only strictly consecutive insertion.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = VersionedCollapsingMergeTree(sign, version)
+[PARTITION BY expr]
+[ORDER BY expr]
+[SAMPLE BY expr]
+[SETTINGS name=value, ...]
+```
+
+For a description of query parameters, see the [query description](../../../sql-reference/statements/create/table.md).
+
+**Engine Parameters**
+
+``` sql
+VersionedCollapsingMergeTree(sign, version)
+```
+
+-   `sign` — Name of the column with the type of row: `1` is a “state” row, `-1` is a “cancel” row.
+
+    The column data type should be `Int8`.
+
+-   `version` — Name of the column with the version of the object state.
+
+    The column data type should be `UInt*`.
+
+**Query Clauses**
+
+When creating a `VersionedCollapsingMergeTree` table, the same [clauses](../../../engines/table-engines/mergetree-family/mergetree.md) are required as when creating a `MergeTree` table.
+
+<details markdown="1">
+
+<summary>Deprecated Method for Creating a Table</summary>
+
+:::warning    
+Do not use this method in new projects. If possible, switch old projects to the method described above.
+:::
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE [=] VersionedCollapsingMergeTree(date-column [, samp#table_engines_versionedcollapsingmergetreeling_expression], (primary, key), index_granularity, sign, version)
+```
+
+All of the parameters except `sign` and `version` have the same meaning as in `MergeTree`.
+
+-   `sign` — Name of the column with the type of row: `1` is a “state” row, `-1` is a “cancel” row.
+
+    Column Data Type — `Int8`.
+
+-   `version` — Name of the column with the version of the object state.
+
+    The column data type should be `UInt*`.
+
+</details>
+
+## Collapsing {#table_engines_versionedcollapsingmergetree}
+
+### Data {#data}
+
+Consider a situation where you need to save continually changing data for some object. It is reasonable to have one row for an object and update the row whenever there are changes. However, the update operation is expensive and slow for a DBMS because it requires rewriting the data in the storage. Update is not acceptable if you need to write data quickly, but you can write the changes to an object sequentially as follows.
+
+Use the `Sign` column when writing the row. If `Sign = 1` it means that the row is a state of an object (let’s call it the “state” row). If `Sign = -1` it indicates the cancellation of the state of an object with the same attributes (let’s call it the “cancel” row). Also use the `Version` column, which should identify each state of an object with a separate number.
+
+For example, we want to calculate how many pages users visited on some site and how long they were there. At some point in time we write the following row with the state of user activity:
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┬─Version─┐
+│ 4324182021466249494 │         5 │      146 │    1 │       1 |
+└─────────────────────┴───────────┴──────────┴──────┴─────────┘
+```
+
+At some point later we register the change of user activity and write it with the following two rows.
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┬─Version─┐
+│ 4324182021466249494 │         5 │      146 │   -1 │       1 |
+│ 4324182021466249494 │         6 │      185 │    1 │       2 |
+└─────────────────────┴───────────┴──────────┴──────┴─────────┘
+```
+
+The first row cancels the previous state of the object (user). It should copy all of the fields of the canceled state except `Sign`.
+
+The second row contains the current state.
+
+Because we need only the last state of user activity, the rows
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┬─Version─┐
+│ 4324182021466249494 │         5 │      146 │    1 │       1 |
+│ 4324182021466249494 │         5 │      146 │   -1 │       1 |
+└─────────────────────┴───────────┴──────────┴──────┴─────────┘
+```
+
+can be deleted, collapsing the invalid (old) state of the object. `VersionedCollapsingMergeTree` does this while merging the data parts.
+
+To find out why we need two rows for each change, see [Algorithm](#table_engines-versionedcollapsingmergetree-algorithm).
+
+**Notes on Usage**
+
+1.  The program that writes the data should remember the state of an object to be able to cancel it. “Cancel” string should contain copies of the primary key fields and the version of the “state” string and the opposite `Sign`. It increases the initial size of storage but allows to write the data quickly.
+2.  Long growing arrays in columns reduce the efficiency of the engine due to the load for writing. The more straightforward the data, the better the efficiency.
+3.  `SELECT` results depend strongly on the consistency of the history of object changes. Be accurate when preparing data for inserting. You can get unpredictable results with inconsistent data, such as negative values for non-negative metrics like session depth.
+
+### Algorithm {#table_engines-versionedcollapsingmergetree-algorithm}
+
+When ClickHouse merges data parts, it deletes each pair of rows that have the same primary key and version and different `Sign`. The order of rows does not matter.
+
+When ClickHouse inserts data, it orders rows by the primary key. If the `Version` column is not in the primary key, ClickHouse adds it to the primary key implicitly as the last field and uses it for ordering.
+
+## Selecting Data {#selecting-data}
+
+ClickHouse does not guarantee that all of the rows with the same primary key will be in the same resulting data part or even on the same physical server. This is true both for writing the data and for subsequent merging of the data parts. In addition, ClickHouse processes `SELECT` queries with multiple threads, and it cannot predict the order of rows in the result. This means that aggregation is required if there is a need to get completely “collapsed” data from a `VersionedCollapsingMergeTree` table.
+
+To finalize collapsing, write a query with a `GROUP BY` clause and aggregate functions that account for the sign. For example, to calculate quantity, use `sum(Sign)` instead of `count()`. To calculate the sum of something, use `sum(Sign * x)` instead of `sum(x)`, and add `HAVING sum(Sign) > 0`.
+
+The aggregates `count`, `sum` and `avg` can be calculated this way. The aggregate `uniq` can be calculated if an object has at least one non-collapsed state. The aggregates `min` and `max` can’t be calculated because `VersionedCollapsingMergeTree` does not save the history of values of collapsed states.
+
+If you need to extract the data with “collapsing” but without aggregation (for example, to check whether rows are present whose newest values match certain conditions), you can use the `FINAL` modifier for the `FROM` clause. This approach is inefficient and should not be used with large tables.
+
+## Example of Use {#example-of-use}
+
+Example data:
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┬─Version─┐
+│ 4324182021466249494 │         5 │      146 │    1 │       1 |
+│ 4324182021466249494 │         5 │      146 │   -1 │       1 |
+│ 4324182021466249494 │         6 │      185 │    1 │       2 |
+└─────────────────────┴───────────┴──────────┴──────┴─────────┘
+```
+
+Creating the table:
+
+``` sql
+CREATE TABLE UAct
+(
+    UserID UInt64,
+    PageViews UInt8,
+    Duration UInt8,
+    Sign Int8,
+    Version UInt8
+)
+ENGINE = VersionedCollapsingMergeTree(Sign, Version)
+ORDER BY UserID
+```
+
+Inserting the data:
+
+``` sql
+INSERT INTO UAct VALUES (4324182021466249494, 5, 146, 1, 1)
+```
+
+``` sql
+INSERT INTO UAct VALUES (4324182021466249494, 5, 146, -1, 1),(4324182021466249494, 6, 185, 1, 2)
+```
+
+We use two `INSERT` queries to create two different data parts. If we insert the data with a single query, ClickHouse creates one data part and will never perform any merge.
+
+Getting the data:
+
+``` sql
+SELECT * FROM UAct
+```
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┬─Version─┐
+│ 4324182021466249494 │         5 │      146 │    1 │       1 │
+└─────────────────────┴───────────┴──────────┴──────┴─────────┘
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┬─Version─┐
+│ 4324182021466249494 │         5 │      146 │   -1 │       1 │
+│ 4324182021466249494 │         6 │      185 │    1 │       2 │
+└─────────────────────┴───────────┴──────────┴──────┴─────────┘
+```
+
+What do we see here and where are the collapsed parts?
+We created two data parts using two `INSERT` queries. The `SELECT` query was performed in two threads, and the result is a random order of rows.
+Collapsing did not occur because the data parts have not been merged yet. ClickHouse merges data parts at an unknown point in time which we cannot predict.
+
+This is why we need aggregation:
+
+``` sql
+SELECT
+    UserID,
+    sum(PageViews * Sign) AS PageViews,
+    sum(Duration * Sign) AS Duration,
+    Version
+FROM UAct
+GROUP BY UserID, Version
+HAVING sum(Sign) > 0
+```
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Version─┐
+│ 4324182021466249494 │         6 │      185 │       2 │
+└─────────────────────┴───────────┴──────────┴─────────┘
+```
+
+If we do not need aggregation and want to force collapsing, we can use the `FINAL` modifier for the `FROM` clause.
+
+``` sql
+SELECT * FROM UAct FINAL
+```
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┬─Version─┐
+│ 4324182021466249494 │         6 │      185 │    1 │       2 │
+└─────────────────────┴───────────┴──────────┴──────┴─────────┘
+```
+
+This is a very inefficient way to select data. Don’t use it for large tables.
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/versionedcollapsingmergetree/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/buffer.md b/docs/en/reference/engines/table-engines/special/buffer.md
new file mode 100644
index 00000000000..a0aff2ec813
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/buffer.md
@@ -0,0 +1,77 @@
+---
+sidebar_position: 120
+sidebar_label:  Buffer
+---
+
+# Buffer Table Engine {#buffer}
+
+Buffers the data to write in RAM, periodically flushing it to another table. During the read operation, data is read from the buffer and the other table simultaneously.
+
+``` sql
+Buffer(database, table, num_layers, min_time, max_time, min_rows, max_rows, min_bytes, max_bytes)
+```
+
+Engine parameters:
+
+-   `database` – Database name. Instead of the database name, you can use a constant expression that returns a string.
+-   `table` – Table to flush data to.
+-   `num_layers` – Parallelism layer. Physically, the table will be represented as `num_layers` of independent buffers. Recommended value: 16.
+-   `min_time`, `max_time`, `min_rows`, `max_rows`, `min_bytes`, and `max_bytes` – Conditions for flushing data from the buffer.
+
+Optional engine parameters:
+
+-   `flush_time`, `flush_rows`, `flush_bytes` – Conditions for flushing data from the buffer, that will happen only in background (omitted or zero means no `flush*` parameters).
+
+Data is flushed from the buffer and written to the destination table if all the `min*` conditions or at least one `max*` condition are met.
+
+Also, if at least one `flush*` condition are met flush initiated in background, this is different from `max*`, since `flush*` allows you to configure background flushes separately to avoid adding latency for `INSERT` (into `Buffer`) queries.
+
+-   `min_time`, `max_time`, `flush_time` – Condition for the time in seconds from the moment of the first write to the buffer.
+-   `min_rows`, `max_rows`, `flush_rows` – Condition for the number of rows in the buffer.
+-   `min_bytes`, `max_bytes`, `flush_bytes` – Condition for the number of bytes in the buffer.
+
+During the write operation, data is inserted to a `num_layers` number of random buffers. Or, if the data part to insert is large enough (greater than `max_rows` or `max_bytes`), it is written directly to the destination table, omitting the buffer.
+
+The conditions for flushing the data are calculated separately for each of the `num_layers` buffers. For example, if `num_layers = 16` and `max_bytes = 100000000`, the maximum RAM consumption is 1.6 GB.
+
+Example:
+
+``` sql
+CREATE TABLE merge.hits_buffer AS merge.hits ENGINE = Buffer(merge, hits, 16, 10, 100, 10000, 1000000, 10000000, 100000000)
+```
+
+Creating a `merge.hits_buffer` table with the same structure as `merge.hits` and using the Buffer engine. When writing to this table, data is buffered in RAM and later written to the ‘merge.hits’ table. 16 buffers are created. The data in each of them is flushed if either 100 seconds have passed, or one million rows have been written, or 100 MB of data have been written; or if simultaneously 10 seconds have passed and 10,000 rows and 10 MB of data have been written. For example, if just one row has been written, after 100 seconds it will be flushed, no matter what. But if many rows have been written, the data will be flushed sooner.
+
+When the server is stopped, with `DROP TABLE` or `DETACH TABLE`, buffer data is also flushed to the destination table.
+
+You can set empty strings in single quotation marks for the database and table name. This indicates the absence of a destination table. In this case, when the data flush conditions are reached, the buffer is simply cleared. This may be useful for keeping a window of data in memory.
+
+When reading from a Buffer table, data is processed both from the buffer and from the destination table (if there is one).
+Note that the Buffer tables does not support an index. In other words, data in the buffer is fully scanned, which might be slow for large buffers. (For data in a subordinate table, the index that it supports will be used.)
+
+If the set of columns in the Buffer table does not match the set of columns in a subordinate table, a subset of columns that exist in both tables is inserted.
+
+If the types do not match for one of the columns in the Buffer table and a subordinate table, an error message is entered in the server log, and the buffer is cleared.
+The same thing happens if the subordinate table does not exist when the buffer is flushed.
+
+:::warning    
+Running ALTER on the Buffer table in releases made before 26 Oct 2021 will cause a `Block structure mismatch` error (see [#15117](https://github.com/ClickHouse/ClickHouse/issues/15117) and [#30565](https://github.com/ClickHouse/ClickHouse/pull/30565)), so deleting the Buffer table and then recreating is the only option. It is advisable to check that this error is fixed in your release before trying to run ALTER on the Buffer table.
+:::
+
+If the server is restarted abnormally, the data in the buffer is lost.
+
+`FINAL` and `SAMPLE` do not work correctly for Buffer tables. These conditions are passed to the destination table, but are not used for processing data in the buffer. If these features are required we recommend only using the Buffer table for writing, while reading from the destination table.
+
+When adding data to a Buffer, one of the buffers is locked. This causes delays if a read operation is simultaneously being performed from the table.
+
+Data that is inserted to a Buffer table may end up in the subordinate table in a different order and in different blocks. Because of this, a Buffer table is difficult to use for writing to a CollapsingMergeTree correctly. To avoid problems, you can set `num_layers` to 1.
+
+If the destination table is replicated, some expected characteristics of replicated tables are lost when writing to a Buffer table. The random changes to the order of rows and sizes of data parts cause data deduplication to quit working, which means it is not possible to have a reliable ‘exactly once’ write to replicated tables.
+
+Due to these disadvantages, we can only recommend using a Buffer table in rare cases.
+
+A Buffer table is used when too many INSERTs are received from a large number of servers over a unit of time and data can’t be buffered before insertion, which means the INSERTs can’t run fast enough.
+
+Note that it does not make sense to insert data one row at a time, even for Buffer tables. This will only produce a speed of a few thousand rows per second, while inserting larger blocks of data can produce over a million rows per second (see the section “Performance”).
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/special/buffer/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/dictionary.md b/docs/en/reference/engines/table-engines/special/dictionary.md
new file mode 100644
index 00000000000..67b97e37d44
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/dictionary.md
@@ -0,0 +1,101 @@
+---
+sidebar_position: 20
+sidebar_label: Dictionary
+---
+
+# Dictionary Table Engine {#dictionary}
+
+The `Dictionary` engine displays the [dictionary](../../../sql-reference/dictionaries/external-dictionaries/external-dicts.md) data as a ClickHouse table.
+
+## Example {#example}
+
+As an example, consider a dictionary of `products` with the following configuration:
+
+``` xml
+<dictionaries>
+    <dictionary>
+        <name>products</name>
+        <source>
+            <odbc>
+                <table>products</table>
+                <connection_string>DSN=some-db-server</connection_string>
+            </odbc>
+        </source>
+        <lifetime>
+            <min>300</min>
+            <max>360</max>
+        </lifetime>
+        <layout>
+            <flat/>
+        </layout>
+        <structure>
+            <id>
+                <name>product_id</name>
+            </id>
+            <attribute>
+                <name>title</name>
+                <type>String</type>
+                <null_value></null_value>
+            </attribute>
+        </structure>
+    </dictionary>
+</dictionaries>
+```
+
+Query the dictionary data:
+
+``` sql
+SELECT
+    name,
+    type,
+    key,
+    attribute.names,
+    attribute.types,
+    bytes_allocated,
+    element_count,
+    source
+FROM system.dictionaries
+WHERE name = 'products'
+```
+
+``` text
+┌─name─────┬─type─┬─key────┬─attribute.names─┬─attribute.types─┬─bytes_allocated─┬─element_count─┬─source──────────┐
+│ products │ Flat │ UInt64 │ ['title']       │ ['String']      │        23065376 │        175032 │ ODBC: .products │
+└──────────┴──────┴────────┴─────────────────┴─────────────────┴─────────────────┴───────────────┴─────────────────┘
+```
+
+You can use the [dictGet\*](../../../sql-reference/functions/ext-dict-functions.md#ext_dict_functions) function to get the dictionary data in this format.
+
+This view isn’t helpful when you need to get raw data, or when performing a `JOIN` operation. For these cases, you can use the `Dictionary` engine, which displays the dictionary data in a table.
+
+Syntax:
+
+``` sql
+CREATE TABLE %table_name% (%fields%) engine = Dictionary(%dictionary_name%)`
+```
+
+Usage example:
+
+``` sql
+create table products (product_id UInt64, title String) Engine = Dictionary(products);
+```
+
+      Ok
+
+Take a look at what’s in the table.
+
+``` sql
+select * from products limit 1;
+```
+
+``` text
+┌────product_id─┬─title───────────┐
+│        152689 │ Some item       │
+└───────────────┴─────────────────┘
+```
+
+**See Also**
+
+-   [Dictionary function](../../../sql-reference/table-functions/dictionary.md#dictionary-function)
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/special/dictionary/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/distributed.md b/docs/en/reference/engines/table-engines/special/distributed.md
new file mode 100644
index 00000000000..db89175e4d9
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/distributed.md
@@ -0,0 +1,229 @@
+---
+sidebar_position: 10
+sidebar_label: Distributed
+---
+
+# Distributed Table Engine {#distributed}
+
+Tables with Distributed engine do not store any data of their own, but allow distributed query processing on multiple servers.
+Reading is automatically parallelized. During a read, the table indexes on remote servers are used, if there are any.
+
+## Creating a Table {#distributed-creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+) ENGINE = Distributed(cluster, database, table[, sharding_key[, policy_name]])
+[SETTINGS name=value, ...]
+```
+
+### From a Table {#distributed-from-a-table}
+When the `Distributed` table is pointing to a table on the current server you can adopt that table's schema:
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster] AS [db2.]name2 ENGINE = Distributed(cluster, database, table[, sharding_key[, policy_name]]) [SETTINGS name=value, ...]
+```
+
+**Distributed Parameters**
+
+-   `cluster` - the cluster name in the server’s config file
+
+-   `database` - the name of a remote database
+
+-   `table` - the name of a remote table
+
+-   `sharding_key` - (optionally) sharding key
+
+-   `policy_name` - (optionally) policy name, it will be used to store temporary files for async send
+
+**See Also**
+
+ - [insert_distributed_sync](../../../operations/settings/settings.md#insert_distributed_sync) setting
+ - [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes) for the examples
+
+**Distributed Settings**
+
+- `fsync_after_insert` - do the `fsync` for the file data after asynchronous insert to Distributed. Guarantees that the OS flushed the whole inserted data to a file **on the initiator node** disk.
+
+- `fsync_directories` - do the `fsync` for directories. Guarantees that the OS refreshed directory metadata after operations related to asynchronous inserts on Distributed table (after insert, after sending the data to shard, etc).
+
+- `bytes_to_throw_insert` - if more than this number of compressed bytes will be pending for async INSERT, an exception will be thrown. 0 - do not throw. Default 0.
+
+- `bytes_to_delay_insert` - if more than this number of compressed bytes will be pending for async INSERT, the query will be delayed. 0 - do not delay. Default 0.
+
+- `max_delay_to_insert` - max delay of inserting data into Distributed table in seconds, if there are a lot of pending bytes for async send. Default 60.
+
+- `monitor_batch_inserts` - same as [distributed_directory_monitor_batch_inserts](../../../operations/settings/settings.md#distributed_directory_monitor_batch_inserts)
+
+- `monitor_split_batch_on_failure` - same as [distributed_directory_monitor_split_batch_on_failure](../../../operations/settings/settings.md#distributed_directory_monitor_split_batch_on_failure)
+
+- `monitor_sleep_time_ms` - same as [distributed_directory_monitor_sleep_time_ms](../../../operations/settings/settings.md#distributed_directory_monitor_sleep_time_ms)
+
+- `monitor_max_sleep_time_ms` - same as [distributed_directory_monitor_max_sleep_time_ms](../../../operations/settings/settings.md#distributed_directory_monitor_max_sleep_time_ms)
+
+:::note
+**Durability settings** (`fsync_...`):
+
+- Affect only asynchronous INSERTs (i.e. `insert_distributed_sync=false`) when data first stored on the initiator node disk and later asynchronously send to shards.
+- May significantly decrease the inserts' performance
+- Affect writing the data stored inside Distributed table folder into the **node which accepted your insert**. If you need to have guarantees of writing data to underlying MergeTree tables - see durability settings (`...fsync...`) in `system.merge_tree_settings`
+
+For **Insert limit settings** (`..._insert`) see also:
+
+- [insert_distributed_sync](../../../operations/settings/settings.md#insert_distributed_sync) setting
+- [prefer_localhost_replica](../../../operations/settings/settings.md#settings-prefer-localhost-replica) setting
+- `bytes_to_throw_insert` handled before `bytes_to_delay_insert`, so you should not set it to the value less then `bytes_to_delay_insert`
+:::
+
+**Example**
+
+``` sql
+CREATE TABLE hits_all AS hits
+ENGINE = Distributed(logs, default, hits[, sharding_key[, policy_name]])
+SETTINGS
+    fsync_after_insert=0,
+    fsync_directories=0;
+```
+
+Data will be read from all servers in the `logs` cluster, from the `default.hits` table located on every server in the cluster.
+Data is not only read but is partially processed on the remote servers (to the extent that this is possible).
+For example, for a query with `GROUP BY`, data will be aggregated on remote servers, and the intermediate states of aggregate functions will be sent to the requestor server. Then data will be further aggregated.
+
+Instead of the database name, you can use a constant expression that returns a string. For example: `currentDatabase()`.
+
+## Clusters {#distributed-clusters}
+
+Clusters are configured in the [server configuration file](../../../operations/configuration-files.md):
+
+``` xml
+<remote_servers>
+    <logs>
+        <!-- Inter-server per-cluster secret for Distributed queries
+             default: no secret (no authentication will be performed)
+
+             If set, then Distributed queries will be validated on shards, so at least:
+             - such cluster should exist on the shard,
+             - such cluster should have the same secret.
+
+             And also (and which is more important), the initial_user will
+             be used as current user for the query.
+        -->
+        <!-- <secret></secret> -->
+        <shard>
+            <!-- Optional. Shard weight when writing data. Default: 1. -->
+            <weight>1</weight>
+            <!-- Optional. Whether to write data to just one of the replicas. Default: false (write data to all replicas). -->
+            <internal_replication>false</internal_replication>
+            <replica>
+                <!-- Optional. Priority of the replica for load balancing (see also load_balancing setting). Default: 1 (less value has more priority). -->
+                <priority>1</priority>
+                <host>example01-01-1</host>
+                <port>9000</port>
+            </replica>
+            <replica>
+                <host>example01-01-2</host>
+                <port>9000</port>
+            </replica>
+        </shard>
+        <shard>
+            <weight>2</weight>
+            <internal_replication>false</internal_replication>
+            <replica>
+                <host>example01-02-1</host>
+                <port>9000</port>
+            </replica>
+            <replica>
+                <host>example01-02-2</host>
+                <secure>1</secure>
+                <port>9440</port>
+            </replica>
+        </shard>
+    </logs>
+</remote_servers>
+```
+
+Here a cluster is defined with the name `logs` that consists of two shards, each of which contains two replicas.
+Shards refer to the servers that contain different parts of the data (in order to read all the data, you must access all the shards).
+Replicas are duplicating servers (in order to read all the data, you can access the data on any one of the replicas).
+
+Cluster names must not contain dots.
+
+The parameters `host`, `port`, and optionally `user`, `password`, `secure`, `compression` are specified for each server:
+
+- `host` – The address of the remote server. You can use either the domain or the IPv4 or IPv6 address. If you specify the domain, the server makes a DNS request when it starts, and the result is stored as long as the server is running. If the DNS request fails, the server does not start. If you change the DNS record, restart the server.
+- `port` – The TCP port for messenger activity (`tcp_port` in the config, usually set to 9000). Not to be confused with `http_port`.
+- `user` – Name of the user for connecting to a remote server. Default value is the `default` user. This user must have access to connect to the specified server. Access is configured in the `users.xml` file. For more information, see the section [Access rights](../../../operations/access-rights.md).
+- `password` – The password for connecting to a remote server (not masked). Default value: empty string.
+- `secure` - Whether to use a secure SSL/TLS connection. Usually also requires specifying the port (the default secure port is `9440`). The server should listen on `<tcp_port_secure>9440</tcp_port_secure>` and be configured with correct certificates.
+- `compression` - Use data compression. Default value: `true`.
+
+When specifying replicas, one of the available replicas will be selected for each of the shards when reading. You can configure the algorithm for load balancing (the preference for which replica to access) – see the [load_balancing](../../../operations/settings/settings.md#settings-load_balancing) setting.
+If the connection with the server is not established, there will be an attempt to connect with a short timeout. If the connection failed, the next replica will be selected, and so on for all the replicas. If the connection attempt failed for all the replicas, the attempt will be repeated the same way, several times.
+This works in favour of resiliency, but does not provide complete fault tolerance: a remote server might accept the connection, but might not work, or work poorly.
+
+You can specify just one of the shards (in this case, query processing should be called remote, rather than distributed) or up to any number of shards. In each shard, you can specify from one to any number of replicas. You can specify a different number of replicas for each shard.
+
+You can specify as many clusters as you wish in the configuration.
+
+To view your clusters, use the `system.clusters` table.
+
+The `Distributed` engine allows working with a cluster like a local server. However, the cluster's configuration cannot be specified dynamically, it has to be configured in the server config file. Usually, all servers in a cluster will have the same cluster config (though this is not required). Clusters from the config file are updated on the fly, without restarting the server.
+
+If you need to send a query to an unknown set of shards and replicas each time, you do not need to create a `Distributed` table – use the `remote` table function instead. See the section [Table functions](../../../sql-reference/table-functions/index.md).
+
+## Writing data {#distributed-writing-data}
+
+There are two methods for writing data to a cluster:
+
+First, you can define which servers to write which data to and perform the write directly on each shard. In other words, perform direct `INSERT` statements on the remote tables in the cluster that the `Distributed` table is pointing to. This is the most flexible solution as you can use any sharding scheme, even one that is non-trivial due to the requirements of the subject area. This is also the most optimal solution since data can be written to different shards completely independently.
+
+Second, you can perform `INSERT` statements on a `Distributed` table. In this case, the table will distribute the inserted data across the servers itself. In order to write to a `Distributed` table, it must have the `sharding_key` parameter configured (except if there is only one shard).
+
+Each shard can have a `<weight>` defined in the config file. By default, the weight is `1`. Data is distributed across shards in the amount proportional to the shard weight. All shard weights are summed up, then each shard's weight is divided by the total to determine each shard's proportion. For example, if there are two shards and the first has a weight of 1 while the second has a weight of 2, the first will be sent one third (1 / 3) of inserted rows and the second will be sent two thirds (2 / 3).
+
+Each shard can have the `internal_replication` parameter defined in the config file. If this parameter is set to `true`, the write operation selects the first healthy replica and writes data to it. Use this if the tables underlying the `Distributed` table are replicated tables (e.g. any of the `Replicated*MergeTree` table engines). One of the table replicas will receive the write and it will be replicated to the other replicas automatically.
+
+If `internal_replication` is set to `false` (the default), data is written to all replicas. In this case, the `Distributed` table replicates data itself. This is worse than using replicated tables because the consistency of replicas is not checked and, over time, they will contain slightly different data.
+
+To select the shard that a row of data is sent to, the sharding expression is analyzed, and its remainder is taken from dividing it by the total weight of the shards. The row is sent to the shard that corresponds to the half-interval of the remainders from `prev_weights` to `prev_weights + weight`, where `prev_weights` is the total weight of the shards with the smallest number, and `weight` is the weight of this shard. For example, if there are two shards, and the first has a weight of 9 while the second has a weight of 10, the row will be sent to the first shard for the remainders from the range \[0, 9), and to the second for the remainders from the range \[9, 19).
+
+The sharding expression can be any expression from constants and table columns that returns an integer. For example, you can use the expression `rand()` for random distribution of data, or `UserID` for distribution by the remainder from dividing the user’s ID (then the data of a single user will reside on a single shard, which simplifies running `IN` and `JOIN` by users). If one of the columns is not distributed evenly enough, you can wrap it in a hash function e.g. `intHash64(UserID)`.
+
+A simple remainder from the division is a limited solution for sharding and isn’t always appropriate. It works for medium and large volumes of data (dozens of servers), but not for very large volumes of data (hundreds of servers or more). In the latter case, use the sharding scheme required by the subject area rather than using entries in `Distributed` tables.
+
+You should be concerned about the sharding scheme in the following cases:
+
+-   Queries are used that require joining data (`IN` or `JOIN`) by a specific key. If data is sharded by this key, you can use local `IN` or `JOIN` instead of `GLOBAL IN` or `GLOBAL JOIN`, which is much more efficient.
+-   A large number of servers is used (hundreds or more) with a large number of small queries, for example, queries for data of individual clients (e.g. websites, advertisers, or partners). In order for the small queries to not affect the entire cluster, it makes sense to locate data for a single client on a single shard. Alternatively, you can set up bi-level sharding: divide the entire cluster into “layers”, where a layer may consist of multiple shards. Data for a single client is located on a single layer, but shards can be added to a layer as necessary, and data is randomly distributed within them. `Distributed` tables are created for each layer, and a single shared distributed table is created for global queries.
+
+Data is written asynchronously. When inserted in the table, the data block is just written to the local file system. The data is sent to the remote servers in the background as soon as possible. The periodicity for sending data is managed by the [distributed_directory_monitor_sleep_time_ms](../../../operations/settings/settings.md#distributed_directory_monitor_sleep_time_ms) and [distributed_directory_monitor_max_sleep_time_ms](../../../operations/settings/settings.md#distributed_directory_monitor_max_sleep_time_ms) settings. The `Distributed` engine sends each file with inserted data separately, but you can enable batch sending of files with the [distributed_directory_monitor_batch_inserts](../../../operations/settings/settings.md#distributed_directory_monitor_batch_inserts) setting. This setting improves cluster performance by better utilizing local server and network resources. You should check whether data is sent successfully by checking the list of files (data waiting to be sent) in the table directory: `/var/lib/clickhouse/data/database/table/`. The number of threads performing background tasks can be set by [background_distributed_schedule_pool_size](../../../operations/settings/settings.md#background_distributed_schedule_pool_size) setting.
+
+If the server ceased to exist or had a rough restart (for example, due to a hardware failure) after an `INSERT` to a `Distributed` table, the inserted data might be lost. If a damaged data part is detected in the table directory, it is transferred to the `broken` subdirectory and no longer used.
+
+## Reading data {#distributed-reading-data}
+
+When querying a `Distributed` table, `SELECT` queries are sent to all shards and work regardless of how data is distributed across the shards (they can be distributed completely randomly). When you add a new shard, you do not have to transfer old data into it. Instead, you can write new data to it by using a heavier weight – the data will be distributed slightly unevenly, but queries will work correctly and efficiently.
+
+When the `max_parallel_replicas` option is enabled, query processing is parallelized across all replicas within a single shard. For more information, see the section [max_parallel_replicas](../../../operations/settings/settings.md#settings-max_parallel_replicas).
+
+To learn more about how distibuted `in` and `global in` queries are processed, refer to [this](../../../sql-reference/operators/in.md#select-distributed-subqueries) documentation. 
+
+## Virtual Columns {#virtual-columns}
+
+-   `_shard_num` — Contains the `shard_num` value from the table `system.clusters`. Type: [UInt32](../../../sql-reference/data-types/int-uint.md).
+
+:::note    
+Since [remote](../../../sql-reference/table-functions/remote.md) and [cluster](../../../sql-reference/table-functions/cluster.md) table functions internally create temporary Distributed table, `_shard_num` is available there too.
+:::
+
+**See Also**
+
+-   [Virtual columns](../../../engines/table-engines/index.md#table_engines-virtual_columns) description
+-   [background_distributed_schedule_pool_size](../../../operations/settings/settings.md#background_distributed_schedule_pool_size) setting
+-   [shardNum()](../../../sql-reference/functions/other-functions.md#shard-num) and [shardCount()](../../../sql-reference/functions/other-functions.md#shard-count) functions
+
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/special/distributed/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/external-data.md b/docs/en/reference/engines/table-engines/special/external-data.md
new file mode 100644
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--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/external-data.md
@@ -0,0 +1,65 @@
+---
+sidebar_position: 130
+sidebar_label: External Data
+---
+
+# External Data for Query Processing {#external-data-for-query-processing}
+
+ClickHouse allows sending a server the data that is needed for processing a query, together with a `SELECT` query. This data is put in a temporary table (see the section “Temporary tables”) and can be used in the query (for example, in `IN` operators).
+
+For example, if you have a text file with important user identifiers, you can upload it to the server along with a query that uses filtration by this list.
+
+If you need to run more than one query with a large volume of external data, do not use this feature. It is better to upload the data to the DB ahead of time.
+
+External data can be uploaded using the command-line client (in non-interactive mode), or using the HTTP interface.
+
+In the command-line client, you can specify a parameters section in the format
+
+``` bash
+--external --file=... [--name=...] [--format=...] [--types=...|--structure=...]
+```
+
+You may have multiple sections like this, for the number of tables being transmitted.
+
+**–external** – Marks the beginning of a clause.
+**–file** – Path to the file with the table dump, or -, which refers to stdin.
+Only a single table can be retrieved from stdin.
+
+The following parameters are optional: **–name**– Name of the table. If omitted, _data is used.
+**–format** – Data format in the file. If omitted, TabSeparated is used.
+
+One of the following parameters is required:**–types** – A list of comma-separated column types. For example: `UInt64,String`. The columns will be named _1, _2, …
+**–structure**– The table structure in the format`UserID UInt64`, `URL String`. Defines the column names and types.
+
+The files specified in ‘file’ will be parsed by the format specified in ‘format’, using the data types specified in ‘types’ or ‘structure’. The table will be uploaded to the server and accessible there as a temporary table with the name in ‘name’.
+
+Examples:
+
+``` bash
+$ echo -ne "1\n2\n3\n" | clickhouse-client --query="SELECT count() FROM test.visits WHERE TraficSourceID IN _data" --external --file=- --types=Int8
+849897
+$ cat /etc/passwd | sed 's/:/\t/g' | clickhouse-client --query="SELECT shell, count() AS c FROM passwd GROUP BY shell ORDER BY c DESC" --external --file=- --name=passwd --structure='login String, unused String, uid UInt16, gid UInt16, comment String, home String, shell String'
+/bin/sh 20
+/bin/false      5
+/bin/bash       4
+/usr/sbin/nologin       1
+/bin/sync       1
+```
+
+When using the HTTP interface, external data is passed in the multipart/form-data format. Each table is transmitted as a separate file. The table name is taken from the file name. The `query_string` is passed the parameters `name_format`, `name_types`, and `name_structure`, where `name` is the name of the table that these parameters correspond to. The meaning of the parameters is the same as when using the command-line client.
+
+Example:
+
+``` bash
+$ cat /etc/passwd | sed 's/:/\t/g' > passwd.tsv
+
+$ curl -F 'passwd=@passwd.tsv;' 'http://localhost:8123/?query=SELECT+shell,+count()+AS+c+FROM+passwd+GROUP+BY+shell+ORDER+BY+c+DESC&passwd_structure=login+String,+unused+String,+uid+UInt16,+gid+UInt16,+comment+String,+home+String,+shell+String'
+/bin/sh 20
+/bin/false      5
+/bin/bash       4
+/usr/sbin/nologin       1
+/bin/sync       1
+```
+
+For distributed query processing, the temporary tables are sent to all the remote servers.
+
diff --git a/docs/en/reference/engines/table-engines/special/file.md b/docs/en/reference/engines/table-engines/special/file.md
new file mode 100644
index 00000000000..6e4449bf1a9
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/file.md
@@ -0,0 +1,89 @@
+---
+sidebar_position: 40
+sidebar_label:  File
+---
+
+# File Table Engine {#table_engines-file}
+
+The File table engine keeps the data in a file in one of the supported [file formats](../../../interfaces/formats.md#formats) (`TabSeparated`, `Native`, etc.).
+
+Usage scenarios:
+
+-   Data export from ClickHouse to file.
+-   Convert data from one format to another.
+-   Updating data in ClickHouse via editing a file on a disk.
+
+## Usage in ClickHouse Server {#usage-in-clickhouse-server}
+
+``` sql
+File(Format)
+```
+
+The `Format` parameter specifies one of the available file formats. To perform
+`SELECT` queries, the format must be supported for input, and to perform
+`INSERT` queries – for output. The available formats are listed in the
+[Formats](../../../interfaces/formats.md#formats) section.
+
+ClickHouse does not allow specifying filesystem path for `File`. It will use folder defined by [path](../../../operations/server-configuration-parameters/settings.md) setting in server configuration.
+
+When creating table using `File(Format)` it creates empty subdirectory in that folder. When data is written to that table, it’s put into `data.Format` file in that subdirectory.
+
+You may manually create this subfolder and file in server filesystem and then [ATTACH](../../../sql-reference/statements/attach.md) it to table information with matching name, so you can query data from that file.
+
+:::warning
+Be careful with this functionality, because ClickHouse does not keep track of external changes to such files. The result of simultaneous writes via ClickHouse and outside of ClickHouse is undefined.
+:::
+
+## Example {#example}
+
+**1.** Set up the `file_engine_table` table:
+
+``` sql
+CREATE TABLE file_engine_table (name String, value UInt32) ENGINE=File(TabSeparated)
+```
+
+By default ClickHouse will create folder `/var/lib/clickhouse/data/default/file_engine_table`.
+
+**2.** Manually create `/var/lib/clickhouse/data/default/file_engine_table/data.TabSeparated` containing:
+
+``` bash
+$ cat data.TabSeparated
+one 1
+two 2
+```
+
+**3.** Query the data:
+
+``` sql
+SELECT * FROM file_engine_table
+```
+
+``` text
+┌─name─┬─value─┐
+│ one  │     1 │
+│ two  │     2 │
+└──────┴───────┘
+```
+
+## Usage in ClickHouse-local {#usage-in-clickhouse-local}
+
+In [clickhouse-local](../../../operations/utilities/clickhouse-local.md) File engine accepts file path in addition to `Format`. Default input/output streams can be specified using numeric or human-readable names like `0` or `stdin`, `1` or `stdout`. It is possible to read and write compressed files based on an additional engine parameter or file extension (`gz`, `br` or `xz`).
+
+**Example:**
+
+``` bash
+$ echo -e "1,2\n3,4" | clickhouse-local -q "CREATE TABLE table (a Int64, b Int64) ENGINE = File(CSV, stdin); SELECT a, b FROM table; DROP TABLE table"
+```
+
+## Details of Implementation {#details-of-implementation}
+
+-   Multiple `SELECT` queries can be performed concurrently, but `INSERT` queries will wait each other.
+-   Supported creating new file by `INSERT` query.
+-   If file exists, `INSERT` would append new values in it.
+-   Not supported:
+    -   `ALTER`
+    -   `SELECT ... SAMPLE`
+    -   Indices
+    -   Replication
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/special/file/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/generate.md b/docs/en/reference/engines/table-engines/special/generate.md
new file mode 100644
index 00000000000..453f3b5db0b
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+++ b/docs/en/reference/engines/table-engines/special/generate.md
@@ -0,0 +1,59 @@
+---
+sidebar_position: 140
+sidebar_label:  GenerateRandom
+---
+
+# GenerateRandom Table Engine {#table_engines-generate}
+
+The GenerateRandom table engine produces random data for given table schema.
+
+Usage examples:
+
+-   Use in test to populate reproducible large table.
+-   Generate random input for fuzzing tests.
+
+## Usage in ClickHouse Server {#usage-in-clickhouse-server}
+
+``` sql
+ENGINE = GenerateRandom(random_seed, max_string_length, max_array_length)
+```
+
+The `max_array_length` and `max_string_length` parameters specify maximum length of all
+array columns and strings correspondingly in generated data.
+
+Generate table engine supports only `SELECT` queries.
+
+It supports all [DataTypes](../../../sql-reference/data-types/index.md) that can be stored in a table except `LowCardinality` and `AggregateFunction`.
+
+## Example {#example}
+
+**1.** Set up the `generate_engine_table` table:
+
+``` sql
+CREATE TABLE generate_engine_table (name String, value UInt32) ENGINE = GenerateRandom(1, 5, 3)
+```
+
+**2.** Query the data:
+
+``` sql
+SELECT * FROM generate_engine_table LIMIT 3
+```
+
+``` text
+┌─name─┬──────value─┐
+│ c4xJ │ 1412771199 │
+│ r    │ 1791099446 │
+│ 7#$  │  124312908 │
+└──────┴────────────┘
+```
+
+## Details of Implementation {#details-of-implementation}
+
+-   Not supported:
+    -   `ALTER`
+    -   `SELECT ... SAMPLE`
+    -   `INSERT`
+    -   Indices
+    -   Replication
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/special/generate/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/index.md b/docs/en/reference/engines/table-engines/special/index.md
new file mode 100644
index 00000000000..f87cd86c891
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/index.md
@@ -0,0 +1,14 @@
+---
+sidebar_position: 50
+sidebar_label: Special
+---
+
+# Special Table Engines {#special-table-engines}
+
+There are three main categories of table engines:
+
+-   [MergeTree engine family](../../../engines/table-engines/mergetree-family/index.md) for main production use.
+-   [Log engine family](../../../engines/table-engines/log-family/index.md) for small temporary data.
+-   [Table engines for integrations](../../../engines/table-engines/integrations/index.md).
+
+The remaining engines are unique in their purpose and are not grouped into families yet, thus they are placed in this “special” category.
diff --git a/docs/en/reference/engines/table-engines/special/join.md b/docs/en/reference/engines/table-engines/special/join.md
new file mode 100644
index 00000000000..7d6f6e99b9f
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/join.md
@@ -0,0 +1,130 @@
+---
+sidebar_position: 70
+sidebar_label: Join
+---
+
+# Join Table Engine {#join}
+
+Optional prepared data structure for usage in [JOIN](../../../sql-reference/statements/select/join.md#select-join) operations.
+
+:::note
+This is not an article about the [JOIN clause](../../../sql-reference/statements/select/join.md#select-join) itself.
+:::
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1] [TTL expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2] [TTL expr2],
+) ENGINE = Join(join_strictness, join_type, k1[, k2, ...])
+```
+
+See the detailed description of the [CREATE TABLE](../../../sql-reference/statements/create/table.md#create-table-query) query.
+
+**Engine Parameters**
+
+-   `join_strictness` – [JOIN strictness](../../../sql-reference/statements/select/join.md#select-join-types).
+-   `join_type` – [JOIN type](../../../sql-reference/statements/select/join.md#select-join-types).
+-   `k1[, k2, ...]` – Key columns from the `USING` clause that the `JOIN` operation is made with.
+
+Enter `join_strictness` and `join_type` parameters without quotes, for example, `Join(ANY, LEFT, col1)`. They must match the `JOIN` operation that the table will be used for. If the parameters do not match, ClickHouse does not throw an exception and may return incorrect data.
+
+## Specifics and Recommendations {#specifics-and-recommendations}
+
+### Data Storage {#data-storage}
+
+`Join` table data is always located in the RAM. When inserting rows into a table, ClickHouse writes data blocks to the directory on the disk so that they can be restored when the server restarts.
+
+If the server restarts incorrectly, the data block on the disk might get lost or damaged. In this case, you may need to manually delete the file with damaged data.
+
+### Selecting and Inserting Data {#selecting-and-inserting-data}
+
+You can use `INSERT` queries to add data to the `Join`-engine tables. If the table was created with the `ANY` strictness, data for duplicate keys are ignored. With the `ALL` strictness, all rows are added.
+
+Main use-cases for `Join`-engine tables are following:
+
+-   Place the table to the right side in a `JOIN` clause.
+-   Call the [joinGet](../../../sql-reference/functions/other-functions.md#joinget) function, which lets you extract data from the table the same way as from a dictionary.
+
+### Deleting Data {#deleting-data}
+
+`ALTER DELETE` queries for `Join`-engine tables are implemented as [mutations](../../../sql-reference/statements/alter/index.md#mutations). `DELETE` mutation reads filtered data and overwrites data of memory and disk.
+
+### Limitations and Settings {#join-limitations-and-settings}
+
+When creating a table, the following settings are applied:
+
+-   [join_use_nulls](../../../operations/settings/settings.md#join_use_nulls)
+-   [max_rows_in_join](../../../operations/settings/query-complexity.md#settings-max_rows_in_join)
+-   [max_bytes_in_join](../../../operations/settings/query-complexity.md#settings-max_bytes_in_join)
+-   [join_overflow_mode](../../../operations/settings/query-complexity.md#settings-join_overflow_mode)
+-   [join_any_take_last_row](../../../operations/settings/settings.md#settings-join_any_take_last_row)
+-   [persistent](../../../operations/settings/settings.md#persistent)
+
+The `Join`-engine tables can’t be used in `GLOBAL JOIN` operations.
+
+The `Join`-engine allows to specify [join_use_nulls](../../../operations/settings/settings.md#join_use_nulls) setting in the `CREATE TABLE` statement. [SELECT](../../../sql-reference/statements/select/index.md) query should have the same `join_use_nulls` value.
+
+## Usage Examples {#example}
+
+Creating the left-side table:
+
+``` sql
+CREATE TABLE id_val(`id` UInt32, `val` UInt32) ENGINE = TinyLog;
+```
+
+``` sql
+INSERT INTO id_val VALUES (1,11)(2,12)(3,13);
+```
+
+Creating the right-side `Join` table:
+
+``` sql
+CREATE TABLE id_val_join(`id` UInt32, `val` UInt8) ENGINE = Join(ANY, LEFT, id);
+```
+
+``` sql
+INSERT INTO id_val_join VALUES (1,21)(1,22)(3,23);
+```
+
+Joining the tables:
+
+``` sql
+SELECT * FROM id_val ANY LEFT JOIN id_val_join USING (id);
+```
+
+``` text
+┌─id─┬─val─┬─id_val_join.val─┐
+│  1 │  11 │              21 │
+│  2 │  12 │               0 │
+│  3 │  13 │              23 │
+└────┴─────┴─────────────────┘
+```
+
+As an alternative, you can retrieve data from the `Join` table, specifying the join key value:
+
+``` sql
+SELECT joinGet('id_val_join', 'val', toUInt32(1));
+```
+
+``` text
+┌─joinGet('id_val_join', 'val', toUInt32(1))─┐
+│                                         21 │
+└────────────────────────────────────────────┘
+```
+
+Deleting a row from the `Join` table:
+
+```sql
+ALTER TABLE id_val_join DELETE WHERE id = 3;
+```
+
+```text
+┌─id─┬─val─┐
+│  1 │  21 │
+└────┴─────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/special/join/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/materializedview.md b/docs/en/reference/engines/table-engines/special/materializedview.md
new file mode 100644
index 00000000000..6c9a5e84f60
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/materializedview.md
@@ -0,0 +1,10 @@
+---
+sidebar_position: 100
+sidebar_label: MaterializedView
+---
+
+# MaterializedView Table Engine {#materializedview}
+
+Used for implementing materialized views (for more information, see [CREATE VIEW](../../../sql-reference/statements/create/view.md#materialized)). For storing data, it uses a different engine that was specified when creating the view. When reading from a table, it just uses that engine.
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/special/materializedview/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/memory.md b/docs/en/reference/engines/table-engines/special/memory.md
new file mode 100644
index 00000000000..1e154a323d1
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/memory.md
@@ -0,0 +1,18 @@
+---
+sidebar_position: 110
+sidebar_label:  Memory
+---
+
+# Memory Table Engine {#memory}
+
+The Memory engine stores data in RAM, in uncompressed form. Data is stored in exactly the same form as it is received when read. In other words, reading from this table is completely free.
+Concurrent data access is synchronized. Locks are short: read and write operations do not block each other.
+Indexes are not supported. Reading is parallelized.
+
+Maximal productivity (over 10 GB/sec) is reached on simple queries, because there is no reading from the disk, decompressing, or deserializing data. (We should note that in many cases, the productivity of the MergeTree engine is almost as high.)
+When restarting a server, data disappears from the table and the table becomes empty.
+Normally, using this table engine is not justified. However, it can be used for tests, and for tasks where maximum speed is required on a relatively small number of rows (up to approximately 100,000,000).
+
+The Memory engine is used by the system for temporary tables with external query data (see the section “External data for processing a query”), and for implementing `GLOBAL IN` (see the section “IN operators”).
+
+[Original article](https://clickhouse.com/docs/en/engines/table-engines/special/memory/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/merge.md b/docs/en/reference/engines/table-engines/special/merge.md
new file mode 100644
index 00000000000..bcad7a0c1f6
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/merge.md
@@ -0,0 +1,85 @@
+---
+sidebar_position: 30
+sidebar_label: Merge
+---
+
+# Merge Table Engine {#merge}
+
+The `Merge` engine (not to be confused with `MergeTree`) does not store data itself, but allows reading from any number of other tables simultaneously.
+
+Reading is automatically parallelized. Writing to a table is not supported. When reading, the indexes of tables that are actually being read are used, if they exist.
+
+## Creating a Table {#creating-a-table}
+
+``` sql
+CREATE TABLE ... Engine=Merge(db_name, tables_regexp)
+```
+
+**Engine Parameters**
+
+- `db_name` — Possible values:
+    - database name, 
+    - constant expression that returns a string with a database name, for example, `currentDatabase()`,
+    - `REGEXP(expression)`, where `expression` is a regular expression to match the DB names.
+
+- `tables_regexp` — A regular expression to match the table names in the specified DB or DBs.
+
+Regular expressions — [re2](https://github.com/google/re2) (supports a subset of PCRE), case-sensitive.
+See the notes about escaping symbols in regular expressions in the "match" section.
+
+## Usage {#usage}
+
+When selecting tables to read, the `Merge` table itself is not selected, even if it matches the regex. This is to avoid loops.
+It is possible to create two `Merge` tables that will endlessly try to read each others' data, but this is not a good idea.
+
+The typical way to use the `Merge` engine is for working with a large number of `TinyLog` tables as if with a single table.
+
+## Examples {#examples}
+
+**Example 1**
+
+Consider two databases `ABC_corporate_site` and `ABC_store`. The `all_visitors` table will contain IDs from the tables `visitors` in both databases.
+
+``` sql
+CREATE TABLE all_visitors (id UInt32) ENGINE=Merge(REGEXP('ABC_*'), 'visitors');
+```
+
+**Example 2**
+
+Let's say you have an old table `WatchLog_old` and decided to change partitioning without moving data to a new table `WatchLog_new`, and you need to see data from both tables.
+
+``` sql
+CREATE TABLE WatchLog_old(date Date, UserId Int64, EventType String, Cnt UInt64) 
+    ENGINE=MergeTree(date, (UserId, EventType), 8192);
+INSERT INTO WatchLog_old VALUES ('2018-01-01', 1, 'hit', 3);
+
+CREATE TABLE WatchLog_new(date Date, UserId Int64, EventType String, Cnt UInt64) 
+    ENGINE=MergeTree PARTITION BY date ORDER BY (UserId, EventType) SETTINGS index_granularity=8192;
+INSERT INTO WatchLog_new VALUES ('2018-01-02', 2, 'hit', 3);
+
+CREATE TABLE WatchLog as WatchLog_old ENGINE=Merge(currentDatabase(), '^WatchLog');
+
+SELECT * FROM WatchLog;
+```
+
+``` text
+┌───────date─┬─UserId─┬─EventType─┬─Cnt─┐
+│ 2018-01-01 │      1 │ hit       │   3 │
+└────────────┴────────┴───────────┴─────┘
+┌───────date─┬─UserId─┬─EventType─┬─Cnt─┐
+│ 2018-01-02 │      2 │ hit       │   3 │
+└────────────┴────────┴───────────┴─────┘
+```
+
+## Virtual Columns {#virtual-columns}
+
+-   `_table` — Contains the name of the table from which data was read. Type: [String](../../../sql-reference/data-types/string.md).
+
+    You can set the constant conditions on `_table` in the `WHERE/PREWHERE` clause (for example, `WHERE _table='xyz'`). In this case the read operation is performed only for that tables where the condition on `_table` is satisfied, so the `_table` column acts as an index.
+
+**See Also**
+
+-   [Virtual columns](../../../engines/table-engines/special/index.md#table_engines-virtual_columns)
+-   [merge](../../../sql-reference/table-functions/merge.md) table function
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/special/merge/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/null.md b/docs/en/reference/engines/table-engines/special/null.md
new file mode 100644
index 00000000000..309b09ba779
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/null.md
@@ -0,0 +1,15 @@
+---
+sidebar_position: 50
+sidebar_label:  'Null'
+---
+
+# Null Table Engine {#null}
+
+When writing to a `Null` table, data is ignored. When reading from a `Null` table, the response is empty.
+
+:::note
+If you are wondering why this is useful, note that you can create a materialized view on a `Null` table. So the data written to the table will end up affecting the view, but original raw data will still be discarded.
+:::
+
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/special/null/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/set.md b/docs/en/reference/engines/table-engines/special/set.md
new file mode 100644
index 00000000000..5fd80ba55fe
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/set.md
@@ -0,0 +1,23 @@
+---
+sidebar_position: 60
+sidebar_label: Set
+---
+
+# Set Table Engine {#set}
+
+A data set that is always in RAM. It is intended for use on the right side of the `IN` operator (see the section “IN operators”).
+
+You can use `INSERT` to insert data in the table. New elements will be added to the data set, while duplicates will be ignored.
+But you can’t perform `SELECT` from the table. The only way to retrieve data is by using it in the right half of the `IN` operator.
+
+Data is always located in RAM. For `INSERT`, the blocks of inserted data are also written to the directory of tables on the disk. When starting the server, this data is loaded to RAM. In other words, after restarting, the data remains in place.
+
+For a rough server restart, the block of data on the disk might be lost or damaged. In the latter case, you may need to manually delete the file with damaged data.
+
+### Limitations and Settings {#join-limitations-and-settings}
+
+When creating a table, the following settings are applied:
+
+-   [persistent](../../../operations/settings/settings.md#persistent)
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/special/set/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/url.md b/docs/en/reference/engines/table-engines/special/url.md
new file mode 100644
index 00000000000..64642623f88
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/url.md
@@ -0,0 +1,92 @@
+---
+sidebar_position: 80
+sidebar_label:  URL
+---
+
+# URL Table Engine {#table_engines-url}
+
+Queries data to/from a remote HTTP/HTTPS server. This engine is similar to the [File](../../../engines/table-engines/special/file.md) engine.
+
+Syntax: `URL(URL [,Format] [,CompressionMethod])`
+
+- The `URL` parameter must conform to the structure of a Uniform Resource Locator. The specified URL must point to a server that uses HTTP or HTTPS. This does not require any additional headers for getting a response from the server.
+
+- The `Format` must be one that ClickHouse can use in `SELECT` queries and, if necessary, in `INSERTs`. For the full list of supported formats, see [Formats](../../../interfaces/formats.md#formats).
+
+- `CompressionMethod` indicates that whether the HTTP body should be compressed. If the compression is enabled, the HTTP packets sent by the URL engine contain 'Content-Encoding' header to indicate which compression method is used. 
+
+To enable compression, please first make sure the remote HTTP endpoint indicated by the `URL` parameter supports corresponding compression algorithm.
+   
+The supported `CompressionMethod` should be one of following:
+- gzip or gz
+- deflate
+- brotli or br
+- lzma or xz
+- zstd or zst
+- lz4
+- bz2
+- snappy
+- none
+
+## Usage {#using-the-engine-in-the-clickhouse-server}
+
+`INSERT` and `SELECT` queries are transformed to `POST` and `GET` requests,
+respectively. For processing `POST` requests, the remote server must support
+[Chunked transfer encoding](https://en.wikipedia.org/wiki/Chunked_transfer_encoding).
+
+You can limit the maximum number of HTTP GET redirect hops using the [max_http_get_redirects](../../../operations/settings/settings.md#setting-max_http_get_redirects) setting.
+
+## Example {#example}
+
+**1.** Create a `url_engine_table` table on the server :
+
+``` sql
+CREATE TABLE url_engine_table (word String, value UInt64)
+ENGINE=URL('http://127.0.0.1:12345/', CSV)
+```
+
+**2.** Create a basic HTTP server using the standard Python 3 tools and
+start it:
+
+``` python3
+from http.server import BaseHTTPRequestHandler, HTTPServer
+
+class CSVHTTPServer(BaseHTTPRequestHandler):
+    def do_GET(self):
+        self.send_response(200)
+        self.send_header('Content-type', 'text/csv')
+        self.end_headers()
+
+        self.wfile.write(bytes('Hello,1\nWorld,2\n', "utf-8"))
+
+if __name__ == "__main__":
+    server_address = ('127.0.0.1', 12345)
+    HTTPServer(server_address, CSVHTTPServer).serve_forever()
+```
+
+``` bash
+$ python3 server.py
+```
+
+**3.** Request data:
+
+``` sql
+SELECT * FROM url_engine_table
+```
+
+``` text
+┌─word──┬─value─┐
+│ Hello │     1 │
+│ World │     2 │
+└───────┴───────┘
+```
+
+## Details of Implementation {#details-of-implementation}
+
+-   Reads and writes can be parallel
+-   Not supported:
+    -   `ALTER` and `SELECT...SAMPLE` operations.
+    -   Indexes.
+    -   Replication.
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/special/url/) <!--hide-->
diff --git a/docs/en/reference/engines/table-engines/special/view.md b/docs/en/reference/engines/table-engines/special/view.md
new file mode 100644
index 00000000000..455c301fb01
--- /dev/null
+++ b/docs/en/reference/engines/table-engines/special/view.md
@@ -0,0 +1,10 @@
+---
+sidebar_position: 90
+sidebar_label:  View
+---
+
+# View Table Engine {#table_engines-view}
+
+Used for implementing views (for more information, see the `CREATE VIEW query`). It does not store data, but only stores the specified `SELECT` query. When reading from a table, it runs this query (and deletes all unnecessary columns from the query).
+
+[Original article](https://clickhouse.com/docs/en/operations/table_engines/special/view/) <!--hide-->
diff --git a/docs/en/reference/getting-started/_category_.yml b/docs/en/reference/getting-started/_category_.yml
new file mode 100644
index 00000000000..4bac4e1ffae
--- /dev/null
+++ b/docs/en/reference/getting-started/_category_.yml
@@ -0,0 +1,8 @@
+position: 1
+label: 'Getting Started'
+collapsible: true
+collapsed: true
+link:
+  type: generated-index
+  title: Getting Started
+  slug: /en/getting-started
\ No newline at end of file
diff --git a/docs/en/reference/getting-started/example-datasets/_category_.yml b/docs/en/reference/getting-started/example-datasets/_category_.yml
new file mode 100644
index 00000000000..060a977eb57
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/_category_.yml
@@ -0,0 +1,8 @@
+position: 10
+label: 'Example Datasets'
+collapsible: true
+collapsed: true
+link:
+  type: generated-index
+  title: Example Datasets
+  slug: /en/example-datasets
\ No newline at end of file
diff --git a/docs/en/reference/getting-started/example-datasets/amplab-benchmark.md b/docs/en/reference/getting-started/example-datasets/amplab-benchmark.md
new file mode 100644
index 00000000000..a87ac53e2e3
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/amplab-benchmark.md
@@ -0,0 +1,127 @@
+---
+sidebar_label: AMPLab Big Data Benchmark
+description: A benchmark dataset used for comparing the performance of data warehousing solutions.
+---
+
+# AMPLab Big Data Benchmark {#amplab-big-data-benchmark}
+
+See https://amplab.cs.berkeley.edu/benchmark/
+
+Sign up for a free account at https://aws.amazon.com. It requires a credit card, email, and phone number. Get a new access key at https://console.aws.amazon.com/iam/home?nc2=h_m_sc#security_credential
+
+Run the following in the console:
+
+``` bash
+$ sudo apt-get install s3cmd
+$ mkdir tiny; cd tiny;
+$ s3cmd sync s3://big-data-benchmark/pavlo/text-deflate/tiny/ .
+$ cd ..
+$ mkdir 1node; cd 1node;
+$ s3cmd sync s3://big-data-benchmark/pavlo/text-deflate/1node/ .
+$ cd ..
+$ mkdir 5nodes; cd 5nodes;
+$ s3cmd sync s3://big-data-benchmark/pavlo/text-deflate/5nodes/ .
+$ cd ..
+```
+
+Run the following ClickHouse queries:
+
+``` sql
+CREATE TABLE rankings_tiny
+(
+    pageURL String,
+    pageRank UInt32,
+    avgDuration UInt32
+) ENGINE = Log;
+
+CREATE TABLE uservisits_tiny
+(
+    sourceIP String,
+    destinationURL String,
+    visitDate Date,
+    adRevenue Float32,
+    UserAgent String,
+    cCode FixedString(3),
+    lCode FixedString(6),
+    searchWord String,
+    duration UInt32
+) ENGINE = MergeTree(visitDate, visitDate, 8192);
+
+CREATE TABLE rankings_1node
+(
+    pageURL String,
+    pageRank UInt32,
+    avgDuration UInt32
+) ENGINE = Log;
+
+CREATE TABLE uservisits_1node
+(
+    sourceIP String,
+    destinationURL String,
+    visitDate Date,
+    adRevenue Float32,
+    UserAgent String,
+    cCode FixedString(3),
+    lCode FixedString(6),
+    searchWord String,
+    duration UInt32
+) ENGINE = MergeTree(visitDate, visitDate, 8192);
+
+CREATE TABLE rankings_5nodes_on_single
+(
+    pageURL String,
+    pageRank UInt32,
+    avgDuration UInt32
+) ENGINE = Log;
+
+CREATE TABLE uservisits_5nodes_on_single
+(
+    sourceIP String,
+    destinationURL String,
+    visitDate Date,
+    adRevenue Float32,
+    UserAgent String,
+    cCode FixedString(3),
+    lCode FixedString(6),
+    searchWord String,
+    duration UInt32
+) ENGINE = MergeTree(visitDate, visitDate, 8192);
+```
+
+Go back to the console:
+
+``` bash
+$ for i in tiny/rankings/*.deflate; do echo $i; zlib-flate -uncompress < $i | clickhouse-client --host=example-perftest01j --query="INSERT INTO rankings_tiny FORMAT CSV"; done
+$ for i in tiny/uservisits/*.deflate; do echo $i; zlib-flate -uncompress < $i | clickhouse-client --host=example-perftest01j --query="INSERT INTO uservisits_tiny FORMAT CSV"; done
+$ for i in 1node/rankings/*.deflate; do echo $i; zlib-flate -uncompress < $i | clickhouse-client --host=example-perftest01j --query="INSERT INTO rankings_1node FORMAT CSV"; done
+$ for i in 1node/uservisits/*.deflate; do echo $i; zlib-flate -uncompress < $i | clickhouse-client --host=example-perftest01j --query="INSERT INTO uservisits_1node FORMAT CSV"; done
+$ for i in 5nodes/rankings/*.deflate; do echo $i; zlib-flate -uncompress < $i | clickhouse-client --host=example-perftest01j --query="INSERT INTO rankings_5nodes_on_single FORMAT CSV"; done
+$ for i in 5nodes/uservisits/*.deflate; do echo $i; zlib-flate -uncompress < $i | clickhouse-client --host=example-perftest01j --query="INSERT INTO uservisits_5nodes_on_single FORMAT CSV"; done
+```
+
+Queries for obtaining data samples:
+
+``` sql
+SELECT pageURL, pageRank FROM rankings_1node WHERE pageRank > 1000
+
+SELECT substring(sourceIP, 1, 8), sum(adRevenue) FROM uservisits_1node GROUP BY substring(sourceIP, 1, 8)
+
+SELECT
+    sourceIP,
+    sum(adRevenue) AS totalRevenue,
+    avg(pageRank) AS pageRank
+FROM rankings_1node ALL INNER JOIN
+(
+    SELECT
+        sourceIP,
+        destinationURL AS pageURL,
+        adRevenue
+    FROM uservisits_1node
+    WHERE (visitDate > '1980-01-01') AND (visitDate < '1980-04-01')
+) USING pageURL
+GROUP BY sourceIP
+ORDER BY totalRevenue DESC
+LIMIT 1
+```
+
+[Original article](https://clickhouse.com/docs/en/getting_started/example_datasets/amplab_benchmark/) <!--hide-->
diff --git a/docs/en/reference/getting-started/example-datasets/brown-benchmark.md b/docs/en/reference/getting-started/example-datasets/brown-benchmark.md
new file mode 100644
index 00000000000..0960756dbe9
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/brown-benchmark.md
@@ -0,0 +1,416 @@
+---
+sidebar_label: Brown University Benchmark
+description: A new analytical benchmark for machine-generated log data
+---
+
+# Brown University Benchmark
+
+`MgBench` is a new analytical benchmark for machine-generated log data, [Andrew Crotty](http://cs.brown.edu/people/acrotty/).
+
+Download the data:
+```
+wget https://datasets.clickhouse.com/mgbench{1..3}.csv.xz
+```
+
+Unpack the data:
+```
+xz -v -d mgbench{1..3}.csv.xz
+```
+
+Create tables:
+```
+CREATE DATABASE mgbench;
+
+
+CREATE TABLE mgbench.logs1 (
+  log_time      DateTime,
+  machine_name  LowCardinality(String),
+  machine_group LowCardinality(String),
+  cpu_idle      Nullable(Float32),
+  cpu_nice      Nullable(Float32),
+  cpu_system    Nullable(Float32),
+  cpu_user      Nullable(Float32),
+  cpu_wio       Nullable(Float32),
+  disk_free     Nullable(Float32),
+  disk_total    Nullable(Float32),
+  part_max_used Nullable(Float32),
+  load_fifteen  Nullable(Float32),
+  load_five     Nullable(Float32),
+  load_one      Nullable(Float32),
+  mem_buffers   Nullable(Float32),
+  mem_cached    Nullable(Float32),
+  mem_free      Nullable(Float32),
+  mem_shared    Nullable(Float32),
+  swap_free     Nullable(Float32),
+  bytes_in      Nullable(Float32),
+  bytes_out     Nullable(Float32)
+)
+ENGINE = MergeTree()
+ORDER BY (machine_group, machine_name, log_time);
+
+
+CREATE TABLE mgbench.logs2 (
+  log_time    DateTime,
+  client_ip   IPv4,
+  request     String,
+  status_code UInt16,
+  object_size UInt64
+)
+ENGINE = MergeTree()
+ORDER BY log_time;
+
+
+CREATE TABLE mgbench.logs3 (
+  log_time     DateTime64,
+  device_id    FixedString(15),
+  device_name  LowCardinality(String),
+  device_type  LowCardinality(String),
+  device_floor UInt8,
+  event_type   LowCardinality(String),
+  event_unit   FixedString(1),
+  event_value  Nullable(Float32)
+)
+ENGINE = MergeTree()
+ORDER BY (event_type, log_time);
+```
+
+Insert data:
+
+```
+clickhouse-client --query "INSERT INTO mgbench.logs1 FORMAT CSVWithNames" < mgbench1.csv
+clickhouse-client --query "INSERT INTO mgbench.logs2 FORMAT CSVWithNames" < mgbench2.csv
+clickhouse-client --query "INSERT INTO mgbench.logs3 FORMAT CSVWithNames" < mgbench3.csv
+```
+
+Run benchmark queries:
+```
+-- Q1.1: What is the CPU/network utilization for each web server since midnight?
+
+SELECT machine_name,
+       MIN(cpu) AS cpu_min,
+       MAX(cpu) AS cpu_max,
+       AVG(cpu) AS cpu_avg,
+       MIN(net_in) AS net_in_min,
+       MAX(net_in) AS net_in_max,
+       AVG(net_in) AS net_in_avg,
+       MIN(net_out) AS net_out_min,
+       MAX(net_out) AS net_out_max,
+       AVG(net_out) AS net_out_avg
+FROM (
+  SELECT machine_name,
+         COALESCE(cpu_user, 0.0) AS cpu,
+         COALESCE(bytes_in, 0.0) AS net_in,
+         COALESCE(bytes_out, 0.0) AS net_out
+  FROM logs1
+  WHERE machine_name IN ('anansi','aragog','urd')
+    AND log_time >= TIMESTAMP '2017-01-11 00:00:00'
+) AS r
+GROUP BY machine_name;
+
+
+-- Q1.2: Which computer lab machines have been offline in the past day?
+
+SELECT machine_name,
+       log_time
+FROM logs1
+WHERE (machine_name LIKE 'cslab%' OR
+       machine_name LIKE 'mslab%')
+  AND load_one IS NULL
+  AND log_time >= TIMESTAMP '2017-01-10 00:00:00'
+ORDER BY machine_name,
+         log_time;
+
+
+-- Q1.3: What are the hourly average metrics during the past 10 days for a specific workstation?
+
+SELECT dt,
+       hr,
+       AVG(load_fifteen) AS load_fifteen_avg,
+       AVG(load_five) AS load_five_avg,
+       AVG(load_one) AS load_one_avg,
+       AVG(mem_free) AS mem_free_avg,
+       AVG(swap_free) AS swap_free_avg
+FROM (
+  SELECT CAST(log_time AS DATE) AS dt,
+         EXTRACT(HOUR FROM log_time) AS hr,
+         load_fifteen,
+         load_five,
+         load_one,
+         mem_free,
+         swap_free
+  FROM logs1
+  WHERE machine_name = 'babbage'
+    AND load_fifteen IS NOT NULL
+    AND load_five IS NOT NULL
+    AND load_one IS NOT NULL
+    AND mem_free IS NOT NULL
+    AND swap_free IS NOT NULL
+    AND log_time >= TIMESTAMP '2017-01-01 00:00:00'
+) AS r
+GROUP BY dt,
+         hr
+ORDER BY dt,
+         hr;
+
+
+-- Q1.4: Over 1 month, how often was each server blocked on disk I/O?
+
+SELECT machine_name,
+       COUNT(*) AS spikes
+FROM logs1
+WHERE machine_group = 'Servers'
+  AND cpu_wio > 0.99
+  AND log_time >= TIMESTAMP '2016-12-01 00:00:00'
+  AND log_time < TIMESTAMP '2017-01-01 00:00:00'
+GROUP BY machine_name
+ORDER BY spikes DESC
+LIMIT 10;
+
+
+-- Q1.5: Which externally reachable VMs have run low on memory?
+
+SELECT machine_name,
+       dt,
+       MIN(mem_free) AS mem_free_min
+FROM (
+  SELECT machine_name,
+         CAST(log_time AS DATE) AS dt,
+         mem_free
+  FROM logs1
+  WHERE machine_group = 'DMZ'
+    AND mem_free IS NOT NULL
+) AS r
+GROUP BY machine_name,
+         dt
+HAVING MIN(mem_free) < 10000
+ORDER BY machine_name,
+         dt;
+
+
+-- Q1.6: What is the total hourly network traffic across all file servers?
+
+SELECT dt,
+       hr,
+       SUM(net_in) AS net_in_sum,
+       SUM(net_out) AS net_out_sum,
+       SUM(net_in) + SUM(net_out) AS both_sum
+FROM (
+  SELECT CAST(log_time AS DATE) AS dt,
+         EXTRACT(HOUR FROM log_time) AS hr,
+         COALESCE(bytes_in, 0.0) / 1000000000.0 AS net_in,
+         COALESCE(bytes_out, 0.0) / 1000000000.0 AS net_out
+  FROM logs1
+  WHERE machine_name IN ('allsorts','andes','bigred','blackjack','bonbon',
+      'cadbury','chiclets','cotton','crows','dove','fireball','hearts','huey',
+      'lindt','milkduds','milkyway','mnm','necco','nerds','orbit','peeps',
+      'poprocks','razzles','runts','smarties','smuggler','spree','stride',
+      'tootsie','trident','wrigley','york')
+) AS r
+GROUP BY dt,
+         hr
+ORDER BY both_sum DESC
+LIMIT 10;
+
+
+-- Q2.1: Which requests have caused server errors within the past 2 weeks?
+
+SELECT *
+FROM logs2
+WHERE status_code >= 500
+  AND log_time >= TIMESTAMP '2012-12-18 00:00:00'
+ORDER BY log_time;
+
+
+-- Q2.2: During a specific 2-week period, was the user password file leaked?
+
+SELECT *
+FROM logs2
+WHERE status_code >= 200
+  AND status_code < 300
+  AND request LIKE '%/etc/passwd%'
+  AND log_time >= TIMESTAMP '2012-05-06 00:00:00'
+  AND log_time < TIMESTAMP '2012-05-20 00:00:00';
+
+
+-- Q2.3: What was the average path depth for top-level requests in the past month?
+
+SELECT top_level,
+       AVG(LENGTH(request) - LENGTH(REPLACE(request, '/', ''))) AS depth_avg
+FROM (
+  SELECT SUBSTRING(request FROM 1 FOR len) AS top_level,
+         request
+  FROM (
+    SELECT POSITION(SUBSTRING(request FROM 2), '/') AS len,
+           request
+    FROM logs2
+    WHERE status_code >= 200
+      AND status_code < 300
+      AND log_time >= TIMESTAMP '2012-12-01 00:00:00'
+  ) AS r
+  WHERE len > 0
+) AS s
+WHERE top_level IN ('/about','/courses','/degrees','/events',
+                    '/grad','/industry','/news','/people',
+                    '/publications','/research','/teaching','/ugrad')
+GROUP BY top_level
+ORDER BY top_level;
+
+
+-- Q2.4: During the last 3 months, which clients have made an excessive number of requests?
+
+SELECT client_ip,
+       COUNT(*) AS num_requests
+FROM logs2
+WHERE log_time >= TIMESTAMP '2012-10-01 00:00:00'
+GROUP BY client_ip
+HAVING COUNT(*) >= 100000
+ORDER BY num_requests DESC;
+
+
+-- Q2.5: What are the daily unique visitors?
+
+SELECT dt,
+       COUNT(DISTINCT client_ip)
+FROM (
+  SELECT CAST(log_time AS DATE) AS dt,
+         client_ip
+  FROM logs2
+) AS r
+GROUP BY dt
+ORDER BY dt;
+
+
+-- Q2.6: What are the average and maximum data transfer rates (Gbps)?
+
+SELECT AVG(transfer) / 125000000.0 AS transfer_avg,
+       MAX(transfer) / 125000000.0 AS transfer_max
+FROM (
+  SELECT log_time,
+         SUM(object_size) AS transfer
+  FROM logs2
+  GROUP BY log_time
+) AS r;
+
+
+-- Q3.1: Did the indoor temperature reach freezing over the weekend?
+
+SELECT *
+FROM logs3
+WHERE event_type = 'temperature'
+  AND event_value <= 32.0
+  AND log_time >= '2019-11-29 17:00:00.000';
+
+
+-- Q3.4: Over the past 6 months, how frequently were each door opened?
+
+SELECT device_name,
+       device_floor,
+       COUNT(*) AS ct
+FROM logs3
+WHERE event_type = 'door_open'
+  AND log_time >= '2019-06-01 00:00:00.000'
+GROUP BY device_name,
+         device_floor
+ORDER BY ct DESC;
+
+
+-- Q3.5: Where in the building do large temperature variations occur in winter and summer?
+
+WITH temperature AS (
+  SELECT dt,
+         device_name,
+         device_type,
+         device_floor
+  FROM (
+    SELECT dt,
+           hr,
+           device_name,
+           device_type,
+           device_floor,
+           AVG(event_value) AS temperature_hourly_avg
+    FROM (
+      SELECT CAST(log_time AS DATE) AS dt,
+             EXTRACT(HOUR FROM log_time) AS hr,
+             device_name,
+             device_type,
+             device_floor,
+             event_value
+      FROM logs3
+      WHERE event_type = 'temperature'
+    ) AS r
+    GROUP BY dt,
+             hr,
+             device_name,
+             device_type,
+             device_floor
+  ) AS s
+  GROUP BY dt,
+           device_name,
+           device_type,
+           device_floor
+  HAVING MAX(temperature_hourly_avg) - MIN(temperature_hourly_avg) >= 25.0
+)
+SELECT DISTINCT device_name,
+       device_type,
+       device_floor,
+       'WINTER'
+FROM temperature
+WHERE dt >= DATE '2018-12-01'
+  AND dt < DATE '2019-03-01'
+UNION
+SELECT DISTINCT device_name,
+       device_type,
+       device_floor,
+       'SUMMER'
+FROM temperature
+WHERE dt >= DATE '2019-06-01'
+  AND dt < DATE '2019-09-01';
+
+
+-- Q3.6: For each device category, what are the monthly power consumption metrics?
+
+SELECT yr,
+       mo,
+       SUM(coffee_hourly_avg) AS coffee_monthly_sum,
+       AVG(coffee_hourly_avg) AS coffee_monthly_avg,
+       SUM(printer_hourly_avg) AS printer_monthly_sum,
+       AVG(printer_hourly_avg) AS printer_monthly_avg,
+       SUM(projector_hourly_avg) AS projector_monthly_sum,
+       AVG(projector_hourly_avg) AS projector_monthly_avg,
+       SUM(vending_hourly_avg) AS vending_monthly_sum,
+       AVG(vending_hourly_avg) AS vending_monthly_avg
+FROM (
+  SELECT dt,
+         yr,
+         mo,
+         hr,
+         AVG(coffee) AS coffee_hourly_avg,
+         AVG(printer) AS printer_hourly_avg,
+         AVG(projector) AS projector_hourly_avg,
+         AVG(vending) AS vending_hourly_avg
+  FROM (
+    SELECT CAST(log_time AS DATE) AS dt,
+           EXTRACT(YEAR FROM log_time) AS yr,
+           EXTRACT(MONTH FROM log_time) AS mo,
+           EXTRACT(HOUR FROM log_time) AS hr,
+           CASE WHEN device_name LIKE 'coffee%' THEN event_value END AS coffee,
+           CASE WHEN device_name LIKE 'printer%' THEN event_value END AS printer,
+           CASE WHEN device_name LIKE 'projector%' THEN event_value END AS projector,
+           CASE WHEN device_name LIKE 'vending%' THEN event_value END AS vending
+    FROM logs3
+    WHERE device_type = 'meter'
+  ) AS r
+  GROUP BY dt,
+           yr,
+           mo,
+           hr
+) AS s
+GROUP BY yr,
+         mo
+ORDER BY yr,
+         mo;
+```
+
+The data is also available for interactive queries in the [Playground](https://gh-api.clickhouse.com/play?user=play), [example](https://gh-api.clickhouse.com/play?user=play#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).
+
+[Original article](https://clickhouse.com/docs/en/getting_started/example_datasets/brown-benchmark/) <!--hide-->
diff --git a/docs/en/reference/getting-started/example-datasets/cell-towers.md b/docs/en/reference/getting-started/example-datasets/cell-towers.md
new file mode 100644
index 00000000000..6c3201ff2b2
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/cell-towers.md
@@ -0,0 +1,131 @@
+---
+sidebar_label: Cell Towers
+---
+
+# Cell Towers 
+
+This dataset is from [OpenCellid](https://www.opencellid.org/) - The world's largest Open Database of Cell Towers.
+
+As of 2021, it contains more than 40 million records about cell towers (GSM, LTE, UMTS, etc.) around the world with their geographical coordinates and metadata (country code, network, etc).
+
+OpenCelliD Project is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, and we redistribute a snapshot of this dataset under the terms of the same license. The up-to-date version of the dataset is available to download after sign in.
+
+
+## Get the Dataset {#get-the-dataset}
+
+1. Download the snapshot of the dataset from February 2021: [https://datasets.clickhouse.com/cell_towers.csv.xz] (729 MB).
+
+2. Validate the integrity (optional step):
+```
+md5sum cell_towers.csv.xz
+8cf986f4a0d9f12c6f384a0e9192c908  cell_towers.csv.xz
+```
+
+3. Decompress it with the following command:
+```
+xz -d cell_towers.csv.xz
+```
+
+4. Create a table:
+
+```
+CREATE TABLE cell_towers
+(
+    radio Enum8('' = 0, 'CDMA' = 1, 'GSM' = 2, 'LTE' = 3, 'NR' = 4, 'UMTS' = 5),
+    mcc UInt16,
+    net UInt16,
+    area UInt16,
+    cell UInt64,
+    unit Int16,
+    lon Float64,
+    lat Float64,
+    range UInt32,
+    samples UInt32,
+    changeable UInt8,
+    created DateTime,
+    updated DateTime,
+    averageSignal UInt8
+)
+ENGINE = MergeTree ORDER BY (radio, mcc, net, created);
+```
+
+5. Insert the dataset:
+```
+clickhouse-client --query "INSERT INTO cell_towers FORMAT CSVWithNames" < cell_towers.csv
+```
+
+## Examples {#examples}
+
+1. A number of cell towers by type:
+
+```
+SELECT radio, count() AS c FROM cell_towers GROUP BY radio ORDER BY c DESC
+
+┌─radio─┬────────c─┐
+│ UMTS  │ 20686487 │
+│ LTE   │ 12101148 │
+│ GSM   │  9931312 │
+│ CDMA  │   556344 │
+│ NR    │      867 │
+└───────┴──────────┘
+
+5 rows in set. Elapsed: 0.011 sec. Processed 43.28 million rows, 43.28 MB (3.83 billion rows/s., 3.83 GB/s.)
+```
+
+2. Cell towers by [mobile country code (MCC)](https://en.wikipedia.org/wiki/Mobile_country_code):
+
+```
+SELECT mcc, count() FROM cell_towers GROUP BY mcc ORDER BY count() DESC LIMIT 10
+
+┌─mcc─┬─count()─┐
+│ 310 │ 5024650 │
+│ 262 │ 2622423 │
+│ 250 │ 1953176 │
+│ 208 │ 1891187 │
+│ 724 │ 1836150 │
+│ 404 │ 1729151 │
+│ 234 │ 1618924 │
+│ 510 │ 1353998 │
+│ 440 │ 1343355 │
+│ 311 │ 1332798 │
+└─────┴─────────┘
+
+10 rows in set. Elapsed: 0.019 sec. Processed 43.28 million rows, 86.55 MB (2.33 billion rows/s., 4.65 GB/s.)
+```
+
+So, the top countries are: the USA, Germany, and Russia.
+
+You may want to create an [External Dictionary](../sql-reference/dictionaries/external-dictionaries/external-dicts.md) in ClickHouse to decode these values.
+
+
+## Use case {#use-case}
+
+Using `pointInPolygon` function.
+
+1. Create a table where we will store polygons:
+
+```
+CREATE TEMPORARY TABLE moscow (polygon Array(Tuple(Float64, Float64)));
+```
+
+2. This is a rough shape of Moscow (without "new Moscow"):
+
+```
+INSERT INTO moscow VALUES ([(37.84172564285271, 55.78000432402266), (37.8381207618713, 55.775874525970494), (37.83979446823122, 55.775626746008065), (37.84243326983639, 55.77446586811748), (37.84262672750849, 55.771974101091104), (37.84153238623039, 55.77114545193181), (37.841124690460184, 55.76722010265554), (37.84239076983644, 55.76654891107098), (37.842283558197025, 55.76258709833121), (37.8421759312134, 55.758073999993734), (37.84198330422974, 55.75381499999371), (37.8416827275085, 55.749277102484484), (37.84157576190186, 55.74794544108413), (37.83897929098507, 55.74525257875241), (37.83739676451868, 55.74404373042019), (37.838732481460525, 55.74298009816793), (37.841183997352545, 55.743060321833575), (37.84097476190185, 55.73938799999373), (37.84048155819702, 55.73570799999372), (37.840095812164286, 55.73228210777237), (37.83983814285274, 55.73080491981639), (37.83846476321406, 55.729799917464675), (37.83835745269769, 55.72919751082619), (37.838636380279524, 55.72859509486539), (37.8395161005249, 55.727705075632784), (37.83897964285276, 55.722727886185154), (37.83862557539366, 55.72034817326636), (37.83559735744853, 55.71944437307499), (37.835370708803126, 55.71831419154461), (37.83738169402022, 55.71765218986692), (37.83823396494291, 55.71691750159089), (37.838056931213345, 55.71547311301385), (37.836812846557606, 55.71221445615604), (37.83522525396725, 55.709331054395555), (37.83269301586908, 55.70953687463627), (37.829667367706236, 55.70903403789297), (37.83311126588435, 55.70552351822608), (37.83058993121339, 55.70041317726053), (37.82983872750851, 55.69883771404813), (37.82934501586913, 55.69718947487017), (37.828926414016685, 55.69504441658371), (37.82876530422971, 55.69287499999378), (37.82894754100031, 55.690759754047335), (37.827697554878185, 55.68951421135665), (37.82447346292115, 55.68965045405069), (37.83136543914793, 55.68322046195302), (37.833554015869154, 55.67814012759211), (37.83544184655761, 55.67295011628339), (37.837480388885474, 55.6672498719639), (37.838960677246064, 55.66316274139358), (37.83926093121332, 55.66046999999383), (37.839025050262435, 55.65869897264431), (37.83670784390257, 55.65794084879904), (37.835656529083245, 55.65694309303843), (37.83704060449217, 55.65689306460552), (37.83696819873806, 55.65550363526252), (37.83760389616388, 55.65487847246661), (37.83687972750851, 55.65356745541324), (37.83515216004943, 55.65155951234079), (37.83312418518067, 55.64979413590619), (37.82801726983639, 55.64640836412121), (37.820614174591, 55.64164525405531), (37.818908190475426, 55.6421883258084), (37.81717543386075, 55.64112490388471), (37.81690987037274, 55.63916106913107), (37.815099354492155, 55.637925371757085), (37.808769150787356, 55.633798276884455), (37.80100123544311, 55.62873670012244), (37.79598013491824, 55.62554336109055), (37.78634567724606, 55.62033499605651), (37.78334147619623, 55.618768681480326), (37.77746201055901, 55.619855533402706), (37.77527329626457, 55.61909966711279), (37.77801986242668, 55.618770300976294), (37.778212973541216, 55.617257701952106), (37.77784818518065, 55.61574504433011), (37.77016867724609, 55.61148576294007), (37.760191219573976, 55.60599579539028), (37.75338926983641, 55.60227892751446), (37.746329965606634, 55.59920577639331), (37.73939925396728, 55.59631430313617), (37.73273665739439, 55.5935318803559), (37.7299954450912, 55.59350760316188), (37.7268679946899, 55.59469840523759), (37.72626726983634, 55.59229549697373), (37.7262673598022, 55.59081598950582), (37.71897193121335, 55.5877595845419), (37.70871550793456, 55.58393177431724), (37.700497489410374, 55.580917323756644), (37.69204305026244, 55.57778089778455), (37.68544477378839, 55.57815154690915), (37.68391050793454, 55.57472945079756), (37.678803592590306, 55.57328235936491), (37.6743402539673, 55.57255251445782), (37.66813862698363, 55.57216388774464), (37.617927457672096, 55.57505691895805), (37.60443099999999, 55.5757737568051), (37.599683515869145, 55.57749105910326), (37.59754177842709, 55.57796291823627), (37.59625834786988, 55.57906686095235), (37.59501783265684, 55.57746616444403), (37.593090671936025, 55.57671634534502), (37.587018007904, 55.577944600233785), (37.578692203704804, 55.57982895000019), (37.57327546607398, 55.58116294118248), (37.57385012109279, 55.581550362779), (37.57399562266922, 55.5820107079112), (37.5735356072979, 55.58226289171689), (37.57290393054962, 55.582393529795155), (37.57037722355653, 55.581919415056234), (37.5592298306885, 55.584471614867844), (37.54189249206543, 55.58867650795186), (37.5297256269836, 55.59158133551745), (37.517837865081766, 55.59443656218868), (37.51200186508174, 55.59635625174229), (37.506808949737554, 55.59907823904434), (37.49820432275389, 55.6062944994944), (37.494406071441674, 55.60967103463367), (37.494760001358024, 55.61066689753365), (37.49397137107085, 55.61220931698269), (37.49016528606031, 55.613417718449064), (37.48773249206542, 55.61530616333343), (37.47921386508177, 55.622640129112334), (37.470652153442394, 55.62993723476164), (37.46273446298218, 55.6368075123157), (37.46350692265317, 55.64068225239439), (37.46050283203121, 55.640794546982576), (37.457627470916734, 55.64118904154646), (37.450718034393326, 55.64690488145138), (37.44239252645875, 55.65397824729769), (37.434587576721185, 55.66053543155961), (37.43582144975277, 55.661693766520735), (37.43576786245721, 55.662755031737014), (37.430982915344174, 55.664610641628116), (37.428547447097685, 55.66778515273695), (37.42945134592044, 55.668633314343566), (37.42859571562949, 55.66948145750025), (37.4262836402282, 55.670813882451405), (37.418709037048295, 55.6811141674414), (37.41922139651101, 55.68235377885389), (37.419218771842885, 55.68359335082235), (37.417196501327446, 55.684375235224735), (37.41607020370478, 55.68540557585352), (37.415640857147146, 55.68686637150793), (37.414632153442334, 55.68903015131686), (37.413344899475064, 55.690896881757396), (37.41171432275391, 55.69264232162232), (37.40948282275393, 55.69455101638112), (37.40703674603271, 55.69638690385348), (37.39607169577025, 55.70451821283731), (37.38952706878662, 55.70942491932811), (37.387778313491815, 55.71149057784176), (37.39049275399779, 55.71419814298992), (37.385557272491454, 55.7155489617061), (37.38388335714726, 55.71849856042102), (37.378368238098155, 55.7292763261685), (37.37763597123337, 55.730845879211614), (37.37890062088197, 55.73167906388319), (37.37750451918789, 55.734703664681774), (37.375610832015965, 55.734851959522246), (37.3723813571472, 55.74105626086403), (37.37014935714723, 55.746115620904355), (37.36944173016362, 55.750883999993725), (37.36975304365541, 55.76335905525834), (37.37244070571134, 55.76432079697595), (37.3724259757175, 55.76636979670426), (37.369922155757884, 55.76735417953104), (37.369892695770275, 55.76823419316575), (37.370214730163575, 55.782312184391266), (37.370493611114505, 55.78436801120489), (37.37120164550783, 55.78596427165359), (37.37284851456452, 55.7874378183096), (37.37608325135799, 55.7886695054807), (37.3764587460632, 55.78947647305964), (37.37530000265506, 55.79146512926804), (37.38235915344241, 55.79899647809345), (37.384344043655396, 55.80113596939471), (37.38594269577028, 55.80322699999366), (37.38711208598329, 55.804919036911976), (37.3880239841309, 55.806610999993666), (37.38928977249147, 55.81001864976979), (37.39038389947512, 55.81348641242801), (37.39235781481933, 55.81983538336746), (37.393709457672124, 55.82417822811877), (37.394685720901464, 55.82792275755836), (37.39557615344238, 55.830447148154136), (37.39844478226658, 55.83167107969975), (37.40019761214057, 55.83151823557964), (37.400398790382326, 55.83264967594742), (37.39659544313046, 55.83322180909622), (37.39667059524539, 55.83402792148566), (37.39682089947515, 55.83638877400216), (37.39643489154053, 55.83861656112751), (37.3955338994751, 55.84072348043264), (37.392680272491454, 55.84502158126453), (37.39241188227847, 55.84659117913199), (37.392529730163616, 55.84816071336481), (37.39486835714723, 55.85288092980303), (37.39873052645878, 55.859893456073635), (37.40272161111449, 55.86441833633205), (37.40697072750854, 55.867579567544375), (37.410007082016016, 55.868369880337), (37.4120992989502, 55.86920843741314), (37.412668021163924, 55.87055369615854), (37.41482461111453, 55.87170587948249), (37.41862266137694, 55.873183961039565), (37.42413732540892, 55.874879126654704), (37.4312182698669, 55.875614937236705), (37.43111093783558, 55.8762723478417), (37.43332105622856, 55.87706546369396), (37.43385747619623, 55.87790681284802), (37.441303050262405, 55.88027084462084), (37.44747234260555, 55.87942070143253), (37.44716141796871, 55.88072960917233), (37.44769797085568, 55.88121221323979), (37.45204320500181, 55.882080694420715), (37.45673176190186, 55.882346110794586), (37.463383999999984, 55.88252729504517), (37.46682797486874, 55.88294937719063), (37.470014457672086, 55.88361266759345), (37.47751410450743, 55.88546991372396), (37.47860317658232, 55.88534929207307), (37.48165826025772, 55.882563306475106), (37.48316434442331, 55.8815803226785), (37.483831555817645, 55.882427612793315), (37.483182967125686, 55.88372791409729), (37.483092277908824, 55.88495581062434), (37.4855716508179, 55.8875561994203), (37.486440636245746, 55.887827444039566), (37.49014203439328, 55.88897899871799), (37.493210285705544, 55.890208937135604), (37.497512451065035, 55.891342397444696), (37.49780744510645, 55.89174030252967), (37.49940333499519, 55.89239745507079), (37.50018383334346, 55.89339220941865), (37.52421672750851, 55.903869074155224), (37.52977457672118, 55.90564076517974), (37.53503220370484, 55.90661661218259), (37.54042858064267, 55.90714113744566), (37.54320461007303, 55.905645048442985), (37.545686966066306, 55.906608607018505), (37.54743976120755, 55.90788552162358), (37.55796999999999, 55.90901557907218), (37.572711542327866, 55.91059395704873), (37.57942799999998, 55.91073854155573), (37.58502865872187, 55.91009969268444), (37.58739968913264, 55.90794809960554), (37.59131567193598, 55.908713267595054), (37.612687423278814, 55.902866854295375), (37.62348079629517, 55.90041967242986), (37.635797880950896, 55.898141151686396), (37.649487626983664, 55.89639275532968), (37.65619302513125, 55.89572360207488), (37.66294133862307, 55.895295577183965), (37.66874564418033, 55.89505457604897), (37.67375601586915, 55.89254677027454), (37.67744661901856, 55.8947775867987), (37.688347, 55.89450045676125), (37.69480554232789, 55.89422926332761), (37.70107096560668, 55.89322256101114), (37.705962965606716, 55.891763491662616), (37.711885134918205, 55.889110234998974), (37.71682005026245, 55.886577568759876), (37.7199315476074, 55.88458159806678), (37.72234560316464, 55.882281005794134), (37.72364385977171, 55.8809452036196), (37.725371142837474, 55.8809722706006), (37.727870902099546, 55.88037213862385), (37.73394330422971, 55.877941504088696), (37.745339592590376, 55.87208120378722), (37.75525267724611, 55.86703807949492), (37.76919976190188, 55.859821640197474), (37.827835219574, 55.82962968399116), (37.83341438888553, 55.82575289922351), (37.83652584655761, 55.82188784027888), (37.83809213491821, 55.81612575504693), (37.83605359521481, 55.81460347077685), (37.83632178569025, 55.81276696067908), (37.838623105812026, 55.811486181656385), (37.83912198147584, 55.807329380532785), (37.839079078033414, 55.80510270463816), (37.83965844708251, 55.79940712529036), (37.840581150787344, 55.79131399999368), (37.84172564285271, 55.78000432402266)]);
+```
+
+3. Check how many cell towers are in Moscow:
+
+```
+SELECT count() FROM cell_towers WHERE pointInPolygon((lon, lat), (SELECT * FROM moscow))
+
+┌─count()─┐
+│  310463 │
+└─────────┘
+
+1 rows in set. Elapsed: 0.067 sec. Processed 43.28 million rows, 692.42 MB (645.83 million rows/s., 10.33 GB/s.)
+```
+
+The data is also available for interactive queries in the [Playground](https://gh-api.clickhouse.com/play?user=play), [example](https://gh-api.clickhouse.com/play?user=play#U0VMRUNUIG1jYywgY291bnQoKSBGUk9NIGNlbGxfdG93ZXJzIEdST1VQIEJZIG1jYyBPUkRFUiBCWSBjb3VudCgpIERFU0M=).
+
+Although you cannot create temporary tables there.
\ No newline at end of file
diff --git a/docs/en/reference/getting-started/example-datasets/criteo.md b/docs/en/reference/getting-started/example-datasets/criteo.md
new file mode 100644
index 00000000000..2d1c700d15c
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/criteo.md
@@ -0,0 +1,78 @@
+---
+sidebar_label: Terabyte Click Logs from Criteo
+---
+
+# Terabyte of Click Logs from Criteo 
+
+Download the data from http://labs.criteo.com/downloads/download-terabyte-click-logs/
+
+Create a table to import the log to:
+
+``` sql
+CREATE TABLE criteo_log (date Date, clicked UInt8, int1 Int32, int2 Int32, int3 Int32, int4 Int32, int5 Int32, int6 Int32, int7 Int32, int8 Int32, int9 Int32, int10 Int32, int11 Int32, int12 Int32, int13 Int32, cat1 String, cat2 String, cat3 String, cat4 String, cat5 String, cat6 String, cat7 String, cat8 String, cat9 String, cat10 String, cat11 String, cat12 String, cat13 String, cat14 String, cat15 String, cat16 String, cat17 String, cat18 String, cat19 String, cat20 String, cat21 String, cat22 String, cat23 String, cat24 String, cat25 String, cat26 String) ENGINE = Log
+```
+
+Download the data:
+
+``` bash
+$ for i in {00..23}; do echo $i; zcat datasets/criteo/day_${i#0}.gz | sed -r 's/^/2000-01-'${i/00/24}'\t/' | clickhouse-client --host=example-perftest01j --query="INSERT INTO criteo_log FORMAT TabSeparated"; done
+```
+
+Create a table for the converted data:
+
+``` sql
+CREATE TABLE criteo
+(
+    date Date,
+    clicked UInt8,
+    int1 Int32,
+    int2 Int32,
+    int3 Int32,
+    int4 Int32,
+    int5 Int32,
+    int6 Int32,
+    int7 Int32,
+    int8 Int32,
+    int9 Int32,
+    int10 Int32,
+    int11 Int32,
+    int12 Int32,
+    int13 Int32,
+    icat1 UInt32,
+    icat2 UInt32,
+    icat3 UInt32,
+    icat4 UInt32,
+    icat5 UInt32,
+    icat6 UInt32,
+    icat7 UInt32,
+    icat8 UInt32,
+    icat9 UInt32,
+    icat10 UInt32,
+    icat11 UInt32,
+    icat12 UInt32,
+    icat13 UInt32,
+    icat14 UInt32,
+    icat15 UInt32,
+    icat16 UInt32,
+    icat17 UInt32,
+    icat18 UInt32,
+    icat19 UInt32,
+    icat20 UInt32,
+    icat21 UInt32,
+    icat22 UInt32,
+    icat23 UInt32,
+    icat24 UInt32,
+    icat25 UInt32,
+    icat26 UInt32
+) ENGINE = MergeTree(date, intHash32(icat1), (date, intHash32(icat1)), 8192)
+```
+
+Transform data from the raw log and put it in the second table:
+
+``` sql
+INSERT INTO criteo SELECT date, clicked, int1, int2, int3, int4, int5, int6, int7, int8, int9, int10, int11, int12, int13, reinterpretAsUInt32(unhex(cat1)) AS icat1, reinterpretAsUInt32(unhex(cat2)) AS icat2, reinterpretAsUInt32(unhex(cat3)) AS icat3, reinterpretAsUInt32(unhex(cat4)) AS icat4, reinterpretAsUInt32(unhex(cat5)) AS icat5, reinterpretAsUInt32(unhex(cat6)) AS icat6, reinterpretAsUInt32(unhex(cat7)) AS icat7, reinterpretAsUInt32(unhex(cat8)) AS icat8, reinterpretAsUInt32(unhex(cat9)) AS icat9, reinterpretAsUInt32(unhex(cat10)) AS icat10, reinterpretAsUInt32(unhex(cat11)) AS icat11, reinterpretAsUInt32(unhex(cat12)) AS icat12, reinterpretAsUInt32(unhex(cat13)) AS icat13, reinterpretAsUInt32(unhex(cat14)) AS icat14, reinterpretAsUInt32(unhex(cat15)) AS icat15, reinterpretAsUInt32(unhex(cat16)) AS icat16, reinterpretAsUInt32(unhex(cat17)) AS icat17, reinterpretAsUInt32(unhex(cat18)) AS icat18, reinterpretAsUInt32(unhex(cat19)) AS icat19, reinterpretAsUInt32(unhex(cat20)) AS icat20, reinterpretAsUInt32(unhex(cat21)) AS icat21, reinterpretAsUInt32(unhex(cat22)) AS icat22, reinterpretAsUInt32(unhex(cat23)) AS icat23, reinterpretAsUInt32(unhex(cat24)) AS icat24, reinterpretAsUInt32(unhex(cat25)) AS icat25, reinterpretAsUInt32(unhex(cat26)) AS icat26 FROM criteo_log;
+
+DROP TABLE criteo_log;
+```
+
+[Original article](https://clickhouse.com/docs/en/getting_started/example_datasets/criteo/) <!--hide-->
diff --git a/docs/en/reference/getting-started/example-datasets/github-events.md b/docs/en/reference/getting-started/example-datasets/github-events.md
new file mode 100644
index 00000000000..3a0cbc3324d
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/github-events.md
@@ -0,0 +1,10 @@
+---
+sidebar_label: GitHub Events
+---
+
+# GitHub Events Dataset
+
+Dataset contains all events on GitHub from 2011 to Dec 6 2020, the size is 3.1 billion records. Download size is 75 GB and it will require up to 200 GB space on disk if stored in a table with lz4 compression.
+
+Full dataset description, insights, download instruction and interactive queries are posted [here](https://ghe.clickhouse.tech/).
+
diff --git a/docs/en/reference/getting-started/example-datasets/menus.md b/docs/en/reference/getting-started/example-datasets/menus.md
new file mode 100644
index 00000000000..c41195223a2
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/menus.md
@@ -0,0 +1,354 @@
+---
+sidebar_label: New York Public Library "What's on the Menu?" Dataset
+---
+
+# New York Public Library "What's on the Menu?" Dataset
+
+The dataset is created by the New York Public Library. It contains historical data on the menus of hotels, restaurants and cafes with the dishes along with their prices.
+
+Source: http://menus.nypl.org/data
+The data is in public domain.
+
+The data is from library's archive and it may be incomplete and difficult for statistical analysis. Nevertheless it is also very yummy.
+The size is just 1.3 million records about dishes in the menus — it's a very small data volume for ClickHouse, but it's still a good example.
+
+## Download the Dataset {#download-dataset}
+
+Run the command:
+
+```bash
+wget https://s3.amazonaws.com/menusdata.nypl.org/gzips/2021_08_01_07_01_17_data.tgz
+```
+
+Replace the link to the up to date link from http://menus.nypl.org/data if needed.
+Download size is about 35 MB.
+
+## Unpack the Dataset {#unpack-dataset}
+
+```bash
+tar xvf 2021_08_01_07_01_17_data.tgz
+```
+
+Uncompressed size is about 150 MB.
+
+The data is normalized consisted of four tables:
+- `Menu` — Information about menus: the name of the restaurant, the date when menu was seen, etc.
+- `Dish` — Information about dishes: the name of the dish along with some characteristic.
+- `MenuPage` — Information about the pages in the menus, because every page belongs to some menu.
+- `MenuItem` — An item of the menu. A dish along with its price on some menu page: links to dish and menu page.
+
+## Create the Tables {#create-tables}
+
+We use [Decimal](../sql-reference/data-types/decimal.md) data type to store prices.
+
+```sql
+CREATE TABLE dish
+(
+    id UInt32,
+    name String,
+    description String,
+    menus_appeared UInt32,
+    times_appeared Int32,
+    first_appeared UInt16,
+    last_appeared UInt16,
+    lowest_price Decimal64(3),
+    highest_price Decimal64(3)
+) ENGINE = MergeTree ORDER BY id;
+
+CREATE TABLE menu
+(
+    id UInt32,
+    name String,
+    sponsor String,
+    event String,
+    venue String,
+    place String,
+    physical_description String,
+    occasion String,
+    notes String,
+    call_number String,
+    keywords String,
+    language String,
+    date String,
+    location String,
+    location_type String,
+    currency String,
+    currency_symbol String,
+    status String,
+    page_count UInt16,
+    dish_count UInt16
+) ENGINE = MergeTree ORDER BY id;
+
+CREATE TABLE menu_page
+(
+    id UInt32,
+    menu_id UInt32,
+    page_number UInt16,
+    image_id String,
+    full_height UInt16,
+    full_width UInt16,
+    uuid UUID
+) ENGINE = MergeTree ORDER BY id;
+
+CREATE TABLE menu_item
+(
+    id UInt32,
+    menu_page_id UInt32,
+    price Decimal64(3),
+    high_price Decimal64(3),
+    dish_id UInt32,
+    created_at DateTime,
+    updated_at DateTime,
+    xpos Float64,
+    ypos Float64
+) ENGINE = MergeTree ORDER BY id;
+```
+
+## Import the Data {#import-data}
+
+Upload data into ClickHouse, run:
+
+```bash
+clickhouse-client --format_csv_allow_single_quotes 0 --input_format_null_as_default 0 --query "INSERT INTO dish FORMAT CSVWithNames" < Dish.csv
+clickhouse-client --format_csv_allow_single_quotes 0 --input_format_null_as_default 0 --query "INSERT INTO menu FORMAT CSVWithNames" < Menu.csv
+clickhouse-client --format_csv_allow_single_quotes 0 --input_format_null_as_default 0 --query "INSERT INTO menu_page FORMAT CSVWithNames" < MenuPage.csv
+clickhouse-client --format_csv_allow_single_quotes 0 --input_format_null_as_default 0 --date_time_input_format best_effort --query "INSERT INTO menu_item FORMAT CSVWithNames" < MenuItem.csv
+```
+
+We use [CSVWithNames](../interfaces/formats.md#csvwithnames) format as the data is represented by CSV with header.
+
+We disable `format_csv_allow_single_quotes` as only double quotes are used for data fields and single quotes can be inside the values and should not confuse the CSV parser.
+
+We disable [input_format_null_as_default](../operations/settings/settings.md#settings-input-format-null-as-default) as our data does not have [NULL](../sql-reference/syntax.md#null-literal). Otherwise ClickHouse will try to parse `\N` sequences and can be confused with `\` in data.
+
+The setting [date_time_input_format best_effort](../operations/settings/settings.md#settings-date_time_input_format) allows to parse [DateTime](../sql-reference/data-types/datetime.md)  fields in wide variety of formats. For example, ISO-8601 without seconds like '2000-01-01 01:02' will be recognized. Without this setting only fixed DateTime format is allowed.
+
+## Denormalize the Data {#denormalize-data}
+
+Data is presented in multiple tables in [normalized form](https://en.wikipedia.org/wiki/Database_normalization#Normal_forms). It means you have to perform [JOIN](../sql-reference/statements/select/join.md#select-join) if you want to query, e.g. dish names from menu items.
+For typical analytical tasks it is way more efficient to deal with pre-JOINed data to avoid doing `JOIN` every time. It is called "denormalized" data.
+
+We will create a table `menu_item_denorm` where will contain all the data JOINed together:
+
+```sql
+CREATE TABLE menu_item_denorm
+ENGINE = MergeTree ORDER BY (dish_name, created_at)
+AS SELECT
+    price,
+    high_price,
+    created_at,
+    updated_at,
+    xpos,
+    ypos,
+    dish.id AS dish_id,
+    dish.name AS dish_name,
+    dish.description AS dish_description,
+    dish.menus_appeared AS dish_menus_appeared,
+    dish.times_appeared AS dish_times_appeared,
+    dish.first_appeared AS dish_first_appeared,
+    dish.last_appeared AS dish_last_appeared,
+    dish.lowest_price AS dish_lowest_price,
+    dish.highest_price AS dish_highest_price,
+    menu.id AS menu_id,
+    menu.name AS menu_name,
+    menu.sponsor AS menu_sponsor,
+    menu.event AS menu_event,
+    menu.venue AS menu_venue,
+    menu.place AS menu_place,
+    menu.physical_description AS menu_physical_description,
+    menu.occasion AS menu_occasion,
+    menu.notes AS menu_notes,
+    menu.call_number AS menu_call_number,
+    menu.keywords AS menu_keywords,
+    menu.language AS menu_language,
+    menu.date AS menu_date,
+    menu.location AS menu_location,
+    menu.location_type AS menu_location_type,
+    menu.currency AS menu_currency,
+    menu.currency_symbol AS menu_currency_symbol,
+    menu.status AS menu_status,
+    menu.page_count AS menu_page_count,
+    menu.dish_count AS menu_dish_count
+FROM menu_item
+    JOIN dish ON menu_item.dish_id = dish.id
+    JOIN menu_page ON menu_item.menu_page_id = menu_page.id
+    JOIN menu ON menu_page.menu_id = menu.id;
+```
+
+## Validate the Data {#validate-data}
+
+Query:
+
+```sql
+SELECT count() FROM menu_item_denorm;
+```
+
+Result:
+
+```text
+┌─count()─┐
+│ 1329175 │
+└─────────┘
+```
+
+## Run Some Queries {#run-queries}
+
+### Averaged historical prices of dishes {#query-averaged-historical-prices}
+
+Query:
+
+```sql
+SELECT
+    round(toUInt32OrZero(extract(menu_date, '^\\d{4}')), -1) AS d,
+    count(),
+    round(avg(price), 2),
+    bar(avg(price), 0, 100, 100)
+FROM menu_item_denorm
+WHERE (menu_currency = 'Dollars') AND (d > 0) AND (d < 2022)
+GROUP BY d
+ORDER BY d ASC;
+```
+
+Result:
+
+```text
+┌────d─┬─count()─┬─round(avg(price), 2)─┬─bar(avg(price), 0, 100, 100)─┐
+│ 1850 │     618 │                  1.5 │ █▍                           │
+│ 1860 │    1634 │                 1.29 │ █▎                           │
+│ 1870 │    2215 │                 1.36 │ █▎                           │
+│ 1880 │    3909 │                 1.01 │ █                            │
+│ 1890 │    8837 │                  1.4 │ █▍                           │
+│ 1900 │  176292 │                 0.68 │ ▋                            │
+│ 1910 │  212196 │                 0.88 │ ▊                            │
+│ 1920 │  179590 │                 0.74 │ ▋                            │
+│ 1930 │   73707 │                  0.6 │ ▌                            │
+│ 1940 │   58795 │                 0.57 │ ▌                            │
+│ 1950 │   41407 │                 0.95 │ ▊                            │
+│ 1960 │   51179 │                 1.32 │ █▎                           │
+│ 1970 │   12914 │                 1.86 │ █▋                           │
+│ 1980 │    7268 │                 4.35 │ ████▎                        │
+│ 1990 │   11055 │                 6.03 │ ██████                       │
+│ 2000 │    2467 │                11.85 │ ███████████▋                 │
+│ 2010 │     597 │                25.66 │ █████████████████████████▋   │
+└──────┴─────────┴──────────────────────┴──────────────────────────────┘
+```
+
+Take it with a grain of salt.
+
+### Burger Prices {#query-burger-prices}
+
+Query:
+
+```sql
+SELECT
+    round(toUInt32OrZero(extract(menu_date, '^\\d{4}')), -1) AS d,
+    count(),
+    round(avg(price), 2),
+    bar(avg(price), 0, 50, 100)
+FROM menu_item_denorm
+WHERE (menu_currency = 'Dollars') AND (d > 0) AND (d < 2022) AND (dish_name ILIKE '%burger%')
+GROUP BY d
+ORDER BY d ASC;
+```
+
+Result:
+
+```text
+┌────d─┬─count()─┬─round(avg(price), 2)─┬─bar(avg(price), 0, 50, 100)───────────┐
+│ 1880 │       2 │                 0.42 │ ▋                                     │
+│ 1890 │       7 │                 0.85 │ █▋                                    │
+│ 1900 │     399 │                 0.49 │ ▊                                     │
+│ 1910 │     589 │                 0.68 │ █▎                                    │
+│ 1920 │     280 │                 0.56 │ █                                     │
+│ 1930 │      74 │                 0.42 │ ▋                                     │
+│ 1940 │     119 │                 0.59 │ █▏                                    │
+│ 1950 │     134 │                 1.09 │ ██▏                                   │
+│ 1960 │     272 │                 0.92 │ █▋                                    │
+│ 1970 │     108 │                 1.18 │ ██▎                                   │
+│ 1980 │      88 │                 2.82 │ █████▋                                │
+│ 1990 │     184 │                 3.68 │ ███████▎                              │
+│ 2000 │      21 │                 7.14 │ ██████████████▎                       │
+│ 2010 │       6 │                18.42 │ ████████████████████████████████████▋ │
+└──────┴─────────┴──────────────────────┴───────────────────────────────────────┘
+```
+
+### Vodka {#query-vodka}
+
+Query:
+
+```sql
+SELECT
+    round(toUInt32OrZero(extract(menu_date, '^\\d{4}')), -1) AS d,
+    count(),
+    round(avg(price), 2),
+    bar(avg(price), 0, 50, 100)
+FROM menu_item_denorm
+WHERE (menu_currency IN ('Dollars', '')) AND (d > 0) AND (d < 2022) AND (dish_name ILIKE '%vodka%')
+GROUP BY d
+ORDER BY d ASC;
+```
+
+Result:
+
+```text
+┌────d─┬─count()─┬─round(avg(price), 2)─┬─bar(avg(price), 0, 50, 100)─┐
+│ 1910 │       2 │                    0 │                             │
+│ 1920 │       1 │                  0.3 │ ▌                           │
+│ 1940 │      21 │                 0.42 │ ▋                           │
+│ 1950 │      14 │                 0.59 │ █▏                          │
+│ 1960 │     113 │                 2.17 │ ████▎                       │
+│ 1970 │      37 │                 0.68 │ █▎                          │
+│ 1980 │      19 │                 2.55 │ █████                       │
+│ 1990 │      86 │                  3.6 │ ███████▏                    │
+│ 2000 │       2 │                 3.98 │ ███████▊                    │
+└──────┴─────────┴──────────────────────┴─────────────────────────────┘
+```
+
+To get vodka we have to write `ILIKE '%vodka%'` and this definitely makes a statement.
+
+### Caviar {#query-caviar}
+
+Let's print caviar prices. Also let's print a name of any dish with caviar.
+
+Query:
+
+```sql
+SELECT
+    round(toUInt32OrZero(extract(menu_date, '^\\d{4}')), -1) AS d,
+    count(),
+    round(avg(price), 2),
+    bar(avg(price), 0, 50, 100),
+    any(dish_name)
+FROM menu_item_denorm
+WHERE (menu_currency IN ('Dollars', '')) AND (d > 0) AND (d < 2022) AND (dish_name ILIKE '%caviar%')
+GROUP BY d
+ORDER BY d ASC;
+```
+
+Result:
+
+```text
+┌────d─┬─count()─┬─round(avg(price), 2)─┬─bar(avg(price), 0, 50, 100)──────┬─any(dish_name)──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ 1090 │       1 │                    0 │                                  │ Caviar                                                                                                                              │
+│ 1880 │       3 │                    0 │                                  │ Caviar                                                                                                                              │
+│ 1890 │      39 │                 0.59 │ █▏                               │ Butter and caviar                                                                                                                   │
+│ 1900 │    1014 │                 0.34 │ ▋                                │ Anchovy Caviar on Toast                                                                                                             │
+│ 1910 │    1588 │                 1.35 │ ██▋                              │ 1/1 Brötchen Caviar                                                                                                                 │
+│ 1920 │     927 │                 1.37 │ ██▋                              │ ASTRAKAN CAVIAR                                                                                                                     │
+│ 1930 │     289 │                 1.91 │ ███▋                             │ Astrachan caviar                                                                                                                    │
+│ 1940 │     201 │                 0.83 │ █▋                               │ (SPECIAL) Domestic Caviar Sandwich                                                                                                  │
+│ 1950 │      81 │                 2.27 │ ████▌                            │ Beluga Caviar                                                                                                                       │
+│ 1960 │     126 │                 2.21 │ ████▍                            │ Beluga Caviar                                                                                                                       │
+│ 1970 │     105 │                 0.95 │ █▊                               │ BELUGA MALOSSOL CAVIAR AMERICAN DRESSING                                                                                            │
+│ 1980 │      12 │                 7.22 │ ██████████████▍                  │ Authentic Iranian Beluga Caviar the world's finest black caviar presented in ice garni and a sampling of chilled 100° Russian vodka │
+│ 1990 │      74 │                14.42 │ ████████████████████████████▋    │ Avocado Salad, Fresh cut avocado with caviare                                                                                       │
+│ 2000 │       3 │                 7.82 │ ███████████████▋                 │ Aufgeschlagenes Kartoffelsueppchen mit Forellencaviar                                                                               │
+│ 2010 │       6 │                15.58 │ ███████████████████████████████▏ │ "OYSTERS AND PEARLS" "Sabayon" of Pearl Tapioca with Island Creek Oysters and Russian Sevruga Caviar                                │
+└──────┴─────────┴──────────────────────┴──────────────────────────────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+At least they have caviar with vodka. Very nice.
+
+## Online Playground {#playground}
+
+The data is uploaded to ClickHouse Playground, [example](https://gh-api.clickhouse.com/play?user=play#U0VMRUNUCiAgICByb3VuZCh0b1VJbnQzMk9yWmVybyhleHRyYWN0KG1lbnVfZGF0ZSwgJ15cXGR7NH0nKSksIC0xKSBBUyBkLAogICAgY291bnQoKSwKICAgIHJvdW5kKGF2ZyhwcmljZSksIDIpLAogICAgYmFyKGF2ZyhwcmljZSksIDAsIDUwLCAxMDApLAogICAgYW55KGRpc2hfbmFtZSkKRlJPTSBtZW51X2l0ZW1fZGVub3JtCldIRVJFIChtZW51X2N1cnJlbmN5IElOICgnRG9sbGFycycsICcnKSkgQU5EIChkID4gMCkgQU5EIChkIDwgMjAyMikgQU5EIChkaXNoX25hbWUgSUxJS0UgJyVjYXZpYXIlJykKR1JPVVAgQlkgZApPUkRFUiBCWSBkIEFTQw==).
diff --git a/docs/en/reference/getting-started/example-datasets/metrica.md b/docs/en/reference/getting-started/example-datasets/metrica.md
new file mode 100644
index 00000000000..c5ef74750a6
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/metrica.md
@@ -0,0 +1,78 @@
+---
+sidebar_label: Web Analytics Data
+description: Dataset consists of two tables containing anonymized web analytics data with hits and visits
+---
+
+# Anonymized Web Analytics Data
+
+Dataset consists of two tables containing anonymized web analytics data with hits (`hits_v1`) and visits (`visits_v1`).
+
+The dataset consists of two tables, either of them can be downloaded as a compressed `tsv.xz` file or as prepared partitions. In addition to that, an extended version of the `hits` table containing 100 million rows is available as TSV at https://datasets.clickhouse.com/hits/tsv/hits_100m_obfuscated_v1.tsv.xz and as prepared partitions at https://datasets.clickhouse.com/hits/partitions/hits_100m_obfuscated_v1.tar.xz.
+
+## Obtaining Tables from Prepared Partitions {#obtaining-tables-from-prepared-partitions}
+
+Download and import hits table:
+
+``` bash
+curl -O https://datasets.clickhouse.com/hits/partitions/hits_v1.tar
+tar xvf hits_v1.tar -C /var/lib/clickhouse # path to ClickHouse data directory
+# check permissions on unpacked data, fix if required
+sudo service clickhouse-server restart
+clickhouse-client --query "SELECT COUNT(*) FROM datasets.hits_v1"
+```
+
+Download and import visits:
+
+``` bash
+curl -O https://datasets.clickhouse.com/visits/partitions/visits_v1.tar
+tar xvf visits_v1.tar -C /var/lib/clickhouse # path to ClickHouse data directory
+# check permissions on unpacked data, fix if required
+sudo service clickhouse-server restart
+clickhouse-client --query "SELECT COUNT(*) FROM datasets.visits_v1"
+```
+
+## Obtaining Tables from Compressed TSV File {#obtaining-tables-from-compressed-tsv-file}
+
+Download and import hits from compressed TSV file:
+
+``` bash
+curl https://datasets.clickhouse.com/hits/tsv/hits_v1.tsv.xz | unxz --threads=`nproc` > hits_v1.tsv
+# Validate the checksum
+md5sum hits_v1.tsv
+# Checksum should be equal to: f3631b6295bf06989c1437491f7592cb
+# now create table
+clickhouse-client --query "CREATE DATABASE IF NOT EXISTS datasets"
+# for hits_v1
+clickhouse-client --query "CREATE TABLE datasets.hits_v1 ( WatchID UInt64,  JavaEnable UInt8,  Title String,  GoodEvent Int16,  EventTime DateTime,  EventDate Date,  CounterID UInt32,  ClientIP UInt32,  ClientIP6 FixedString(16),  RegionID UInt32,  UserID UInt64,  CounterClass Int8,  OS UInt8,  UserAgent UInt8,  URL String,  Referer String,  URLDomain String,  RefererDomain String,  Refresh UInt8,  IsRobot UInt8,  RefererCategories Array(UInt16),  URLCategories Array(UInt16), URLRegions Array(UInt32),  RefererRegions Array(UInt32),  ResolutionWidth UInt16,  ResolutionHeight UInt16,  ResolutionDepth UInt8,  FlashMajor UInt8, FlashMinor UInt8,  FlashMinor2 String,  NetMajor UInt8,  NetMinor UInt8, UserAgentMajor UInt16,  UserAgentMinor FixedString(2),  CookieEnable UInt8, JavascriptEnable UInt8,  IsMobile UInt8,  MobilePhone UInt8,  MobilePhoneModel String,  Params String,  IPNetworkID UInt32,  TraficSourceID Int8, SearchEngineID UInt16,  SearchPhrase String,  AdvEngineID UInt8,  IsArtifical UInt8,  WindowClientWidth UInt16,  WindowClientHeight UInt16,  ClientTimeZone Int16,  ClientEventTime DateTime,  SilverlightVersion1 UInt8, SilverlightVersion2 UInt8,  SilverlightVersion3 UInt32,  SilverlightVersion4 UInt16,  PageCharset String,  CodeVersion UInt32,  IsLink UInt8,  IsDownload UInt8,  IsNotBounce UInt8,  FUniqID UInt64,  HID UInt32,  IsOldCounter UInt8, IsEvent UInt8,  IsParameter UInt8,  DontCountHits UInt8,  WithHash UInt8, HitColor FixedString(1),  UTCEventTime DateTime,  Age UInt8,  Sex UInt8,  Income UInt8,  Interests UInt16,  Robotness UInt8,  GeneralInterests Array(UInt16), RemoteIP UInt32,  RemoteIP6 FixedString(16),  WindowName Int32,  OpenerName Int32,  HistoryLength Int16,  BrowserLanguage FixedString(2),  BrowserCountry FixedString(2),  SocialNetwork String,  SocialAction String,  HTTPError UInt16, SendTiming Int32,  DNSTiming Int32,  ConnectTiming Int32,  ResponseStartTiming Int32,  ResponseEndTiming Int32,  FetchTiming Int32,  RedirectTiming Int32, DOMInteractiveTiming Int32,  DOMContentLoadedTiming Int32,  DOMCompleteTiming Int32,  LoadEventStartTiming Int32,  LoadEventEndTiming Int32, NSToDOMContentLoadedTiming Int32,  FirstPaintTiming Int32,  RedirectCount Int8, SocialSourceNetworkID UInt8,  SocialSourcePage String,  ParamPrice Int64, ParamOrderID String,  ParamCurrency FixedString(3),  ParamCurrencyID UInt16, GoalsReached Array(UInt32),  OpenstatServiceName String,  OpenstatCampaignID String,  OpenstatAdID String,  OpenstatSourceID String,  UTMSource String, UTMMedium String,  UTMCampaign String,  UTMContent String,  UTMTerm String, FromTag String,  HasGCLID UInt8,  RefererHash UInt64,  URLHash UInt64,  CLID UInt32,  YCLID UInt64,  ShareService String,  ShareURL String,  ShareTitle String,  ParsedParams Nested(Key1 String,  Key2 String, Key3 String, Key4 String, Key5 String,  ValueDouble Float64),  IslandID FixedString(16),  RequestNum UInt32,  RequestTry UInt8) ENGINE = MergeTree() PARTITION BY toYYYYMM(EventDate) ORDER BY (CounterID, EventDate, intHash32(UserID)) SAMPLE BY intHash32(UserID) SETTINGS index_granularity = 8192"
+# for hits_100m_obfuscated
+clickhouse-client --query="CREATE TABLE  hits_100m_obfuscated (WatchID UInt64, JavaEnable UInt8, Title String, GoodEvent Int16, EventTime DateTime, EventDate Date, CounterID UInt32, ClientIP UInt32, RegionID UInt32, UserID UInt64, CounterClass Int8, OS UInt8, UserAgent UInt8, URL String, Referer String, Refresh UInt8, RefererCategoryID UInt16, RefererRegionID UInt32, URLCategoryID UInt16, URLRegionID UInt32, ResolutionWidth UInt16, ResolutionHeight UInt16, ResolutionDepth UInt8, FlashMajor UInt8, FlashMinor UInt8, FlashMinor2 String, NetMajor UInt8, NetMinor UInt8, UserAgentMajor UInt16, UserAgentMinor FixedString(2), CookieEnable UInt8, JavascriptEnable UInt8, IsMobile UInt8, MobilePhone UInt8, MobilePhoneModel String, Params String, IPNetworkID UInt32, TraficSourceID Int8, SearchEngineID UInt16, SearchPhrase String, AdvEngineID UInt8, IsArtifical UInt8, WindowClientWidth UInt16, WindowClientHeight UInt16, ClientTimeZone Int16, ClientEventTime DateTime, SilverlightVersion1 UInt8, SilverlightVersion2 UInt8, SilverlightVersion3 UInt32, SilverlightVersion4 UInt16, PageCharset String, CodeVersion UInt32, IsLink UInt8, IsDownload UInt8, IsNotBounce UInt8, FUniqID UInt64, OriginalURL String, HID UInt32, IsOldCounter UInt8, IsEvent UInt8, IsParameter UInt8, DontCountHits UInt8, WithHash UInt8, HitColor FixedString(1), LocalEventTime DateTime, Age UInt8, Sex UInt8, Income UInt8, Interests UInt16, Robotness UInt8, RemoteIP UInt32, WindowName Int32, OpenerName Int32, HistoryLength Int16, BrowserLanguage FixedString(2), BrowserCountry FixedString(2), SocialNetwork String, SocialAction String, HTTPError UInt16, SendTiming UInt32, DNSTiming UInt32, ConnectTiming UInt32, ResponseStartTiming UInt32, ResponseEndTiming UInt32, FetchTiming UInt32, SocialSourceNetworkID UInt8, SocialSourcePage String, ParamPrice Int64, ParamOrderID String, ParamCurrency FixedString(3), ParamCurrencyID UInt16, OpenstatServiceName String, OpenstatCampaignID String, OpenstatAdID String, OpenstatSourceID String, UTMSource String, UTMMedium String, UTMCampaign String, UTMContent String, UTMTerm String, FromTag String, HasGCLID UInt8, RefererHash UInt64, URLHash UInt64, CLID UInt32) ENGINE = MergeTree() PARTITION BY toYYYYMM(EventDate) ORDER  BY (CounterID, EventDate, intHash32(UserID)) SAMPLE BY intHash32(UserID) SETTINGS index_granularity = 8192"
+
+# import data
+cat hits_v1.tsv | clickhouse-client --query "INSERT INTO datasets.hits_v1 FORMAT TSV" --max_insert_block_size=100000
+# optionally you can optimize table
+clickhouse-client --query "OPTIMIZE TABLE datasets.hits_v1 FINAL"
+clickhouse-client --query "SELECT COUNT(*) FROM datasets.hits_v1"
+```
+
+Download and import visits from compressed tsv-file:
+
+``` bash
+curl https://datasets.clickhouse.com/visits/tsv/visits_v1.tsv.xz | unxz --threads=`nproc` > visits_v1.tsv
+# Validate the checksum
+md5sum visits_v1.tsv
+# Checksum should be equal to: 6dafe1a0f24e59e3fc2d0fed85601de6
+# now create table
+clickhouse-client --query "CREATE DATABASE IF NOT EXISTS datasets"
+clickhouse-client --query "CREATE TABLE datasets.visits_v1 ( CounterID UInt32,  StartDate Date,  Sign Int8,  IsNew UInt8,  VisitID UInt64,  UserID UInt64,  StartTime DateTime,  Duration UInt32,  UTCStartTime DateTime,  PageViews Int32,  Hits Int32,  IsBounce UInt8,  Referer String,  StartURL String,  RefererDomain String,  StartURLDomain String,  EndURL String,  LinkURL String,  IsDownload UInt8,  TraficSourceID Int8,  SearchEngineID UInt16,  SearchPhrase String,  AdvEngineID UInt8,  PlaceID Int32,  RefererCategories Array(UInt16),  URLCategories Array(UInt16),  URLRegions Array(UInt32),  RefererRegions Array(UInt32),  IsYandex UInt8,  GoalReachesDepth Int32,  GoalReachesURL Int32,  GoalReachesAny Int32,  SocialSourceNetworkID UInt8,  SocialSourcePage String,  MobilePhoneModel String,  ClientEventTime DateTime,  RegionID UInt32,  ClientIP UInt32,  ClientIP6 FixedString(16),  RemoteIP UInt32,  RemoteIP6 FixedString(16),  IPNetworkID UInt32,  SilverlightVersion3 UInt32,  CodeVersion UInt32,  ResolutionWidth UInt16,  ResolutionHeight UInt16,  UserAgentMajor UInt16,  UserAgentMinor UInt16,  WindowClientWidth UInt16,  WindowClientHeight UInt16,  SilverlightVersion2 UInt8,  SilverlightVersion4 UInt16,  FlashVersion3 UInt16,  FlashVersion4 UInt16,  ClientTimeZone Int16,  OS UInt8,  UserAgent UInt8,  ResolutionDepth UInt8,  FlashMajor UInt8,  FlashMinor UInt8,  NetMajor UInt8,  NetMinor UInt8,  MobilePhone UInt8,  SilverlightVersion1 UInt8,  Age UInt8,  Sex UInt8,  Income UInt8,  JavaEnable UInt8,  CookieEnable UInt8,  JavascriptEnable UInt8,  IsMobile UInt8,  BrowserLanguage UInt16,  BrowserCountry UInt16,  Interests UInt16,  Robotness UInt8,  GeneralInterests Array(UInt16),  Params Array(String),  Goals Nested(ID UInt32, Serial UInt32, EventTime DateTime,  Price Int64,  OrderID String, CurrencyID UInt32),  WatchIDs Array(UInt64),  ParamSumPrice Int64,  ParamCurrency FixedString(3),  ParamCurrencyID UInt16,  ClickLogID UInt64,  ClickEventID Int32,  ClickGoodEvent Int32,  ClickEventTime DateTime,  ClickPriorityID Int32,  ClickPhraseID Int32,  ClickPageID Int32,  ClickPlaceID Int32,  ClickTypeID Int32,  ClickResourceID Int32,  ClickCost UInt32,  ClickClientIP UInt32,  ClickDomainID UInt32,  ClickURL String,  ClickAttempt UInt8,  ClickOrderID UInt32,  ClickBannerID UInt32,  ClickMarketCategoryID UInt32,  ClickMarketPP UInt32,  ClickMarketCategoryName String,  ClickMarketPPName String,  ClickAWAPSCampaignName String,  ClickPageName String,  ClickTargetType UInt16,  ClickTargetPhraseID UInt64,  ClickContextType UInt8,  ClickSelectType Int8,  ClickOptions String,  ClickGroupBannerID Int32,  OpenstatServiceName String,  OpenstatCampaignID String,  OpenstatAdID String,  OpenstatSourceID String,  UTMSource String,  UTMMedium String,  UTMCampaign String,  UTMContent String,  UTMTerm String,  FromTag String,  HasGCLID UInt8,  FirstVisit DateTime,  PredLastVisit Date,  LastVisit Date,  TotalVisits UInt32,  TraficSource    Nested(ID Int8,  SearchEngineID UInt16, AdvEngineID UInt8, PlaceID UInt16, SocialSourceNetworkID UInt8, Domain String, SearchPhrase String, SocialSourcePage String),  Attendance FixedString(16),  CLID UInt32,  YCLID UInt64,  NormalizedRefererHash UInt64,  SearchPhraseHash UInt64,  RefererDomainHash UInt64,  NormalizedStartURLHash UInt64,  StartURLDomainHash UInt64,  NormalizedEndURLHash UInt64,  TopLevelDomain UInt64,  URLScheme UInt64,  OpenstatServiceNameHash UInt64,  OpenstatCampaignIDHash UInt64,  OpenstatAdIDHash UInt64,  OpenstatSourceIDHash UInt64,  UTMSourceHash UInt64,  UTMMediumHash UInt64,  UTMCampaignHash UInt64,  UTMContentHash UInt64,  UTMTermHash UInt64,  FromHash UInt64,  WebVisorEnabled UInt8,  WebVisorActivity UInt32,  ParsedParams    Nested(Key1 String,  Key2 String,  Key3 String,  Key4 String, Key5 String, ValueDouble    Float64),  Market Nested(Type UInt8, GoalID UInt32, OrderID String,  OrderPrice Int64,  PP UInt32,  DirectPlaceID UInt32,  DirectOrderID  UInt32,  DirectBannerID UInt32,  GoodID String, GoodName String, GoodQuantity Int32,  GoodPrice Int64),  IslandID FixedString(16)) ENGINE = CollapsingMergeTree(Sign) PARTITION BY toYYYYMM(StartDate) ORDER BY (CounterID, StartDate, intHash32(UserID), VisitID) SAMPLE BY intHash32(UserID) SETTINGS index_granularity = 8192"
+# import data
+cat visits_v1.tsv | clickhouse-client --query "INSERT INTO datasets.visits_v1 FORMAT TSV" --max_insert_block_size=100000
+# optionally you can optimize table
+clickhouse-client --query "OPTIMIZE TABLE datasets.visits_v1 FINAL"
+clickhouse-client --query "SELECT COUNT(*) FROM datasets.visits_v1"
+```
+
+## Example Queries {#example-queries}
+
+[The ClickHouse tutorial](../../tutorial.md) is based on this web analytics dataset, and the recommended way to get started with this dataset is to go through the tutorial.
+
+Additional examples of queries to these tables can be found among [stateful tests](https://github.com/ClickHouse/ClickHouse/tree/master/tests/queries/1_stateful) of ClickHouse (they are named `test.hits` and `test.visits` there).
diff --git a/docs/en/reference/getting-started/example-datasets/nyc-taxi.md b/docs/en/reference/getting-started/example-datasets/nyc-taxi.md
new file mode 100644
index 00000000000..270aeb4929c
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/nyc-taxi.md
@@ -0,0 +1,392 @@
+---
+sidebar_label: New York Taxi Data
+description: Data for billions of taxi and for-hire vehicle (Uber, Lyft, etc.) trips originating in New York City since 2009
+---
+
+# New York Taxi Data 
+
+This dataset can be obtained in two ways:
+
+-   import from raw data
+-   download of prepared partitions
+
+## How to Import the Raw Data {#how-to-import-the-raw-data}
+
+See https://github.com/toddwschneider/nyc-taxi-data and http://tech.marksblogg.com/billion-nyc-taxi-rides-redshift.html for the description of a dataset and instructions for downloading.
+
+Downloading will result in about 227 GB of uncompressed data in CSV files. The download takes about an hour over a 1 Gbit connection (parallel downloading from s3.amazonaws.com recovers at least half of a 1 Gbit channel).
+Some of the files might not download fully. Check the file sizes and re-download any that seem doubtful.
+
+Some of the files might contain invalid rows. You can fix them as follows:
+
+``` bash
+sed -E '/(.*,){18,}/d' data/yellow_tripdata_2010-02.csv > data/yellow_tripdata_2010-02.csv_
+sed -E '/(.*,){18,}/d' data/yellow_tripdata_2010-03.csv > data/yellow_tripdata_2010-03.csv_
+mv data/yellow_tripdata_2010-02.csv_ data/yellow_tripdata_2010-02.csv
+mv data/yellow_tripdata_2010-03.csv_ data/yellow_tripdata_2010-03.csv
+```
+
+Then the data must be pre-processed in PostgreSQL. This will create selections of points in the polygons (to match points on the map with the boroughs of New York City) and combine all the data into a single denormalized flat table by using a JOIN. To do this, you will need to install PostgreSQL with PostGIS support.
+
+Be careful when running `initialize_database.sh` and manually re-check that all the tables were created correctly.
+
+It takes about 20-30 minutes to process each month’s worth of data in PostgreSQL, for a total of about 48 hours.
+
+You can check the number of downloaded rows as follows:
+
+``` bash
+$ time psql nyc-taxi-data -c "SELECT count(*) FROM trips;"
+## Count
+ 1298979494
+(1 row)
+
+real    7m9.164s
+```
+
+(This is slightly more than 1.1 billion rows reported by Mark Litwintschik in a series of blog posts.)
+
+The data in PostgreSQL uses 370 GB of space.
+
+Exporting the data from PostgreSQL:
+
+``` sql
+COPY
+(
+    SELECT trips.id,
+           trips.vendor_id,
+           trips.pickup_datetime,
+           trips.dropoff_datetime,
+           trips.store_and_fwd_flag,
+           trips.rate_code_id,
+           trips.pickup_longitude,
+           trips.pickup_latitude,
+           trips.dropoff_longitude,
+           trips.dropoff_latitude,
+           trips.passenger_count,
+           trips.trip_distance,
+           trips.fare_amount,
+           trips.extra,
+           trips.mta_tax,
+           trips.tip_amount,
+           trips.tolls_amount,
+           trips.ehail_fee,
+           trips.improvement_surcharge,
+           trips.total_amount,
+           trips.payment_type,
+           trips.trip_type,
+           trips.pickup,
+           trips.dropoff,
+
+           cab_types.type cab_type,
+
+           weather.precipitation_tenths_of_mm rain,
+           weather.snow_depth_mm,
+           weather.snowfall_mm,
+           weather.max_temperature_tenths_degrees_celsius max_temp,
+           weather.min_temperature_tenths_degrees_celsius min_temp,
+           weather.average_wind_speed_tenths_of_meters_per_second wind,
+
+           pick_up.gid pickup_nyct2010_gid,
+           pick_up.ctlabel pickup_ctlabel,
+           pick_up.borocode pickup_borocode,
+           pick_up.boroname pickup_boroname,
+           pick_up.ct2010 pickup_ct2010,
+           pick_up.boroct2010 pickup_boroct2010,
+           pick_up.cdeligibil pickup_cdeligibil,
+           pick_up.ntacode pickup_ntacode,
+           pick_up.ntaname pickup_ntaname,
+           pick_up.puma pickup_puma,
+
+           drop_off.gid dropoff_nyct2010_gid,
+           drop_off.ctlabel dropoff_ctlabel,
+           drop_off.borocode dropoff_borocode,
+           drop_off.boroname dropoff_boroname,
+           drop_off.ct2010 dropoff_ct2010,
+           drop_off.boroct2010 dropoff_boroct2010,
+           drop_off.cdeligibil dropoff_cdeligibil,
+           drop_off.ntacode dropoff_ntacode,
+           drop_off.ntaname dropoff_ntaname,
+           drop_off.puma dropoff_puma
+    FROM trips
+    LEFT JOIN cab_types
+        ON trips.cab_type_id = cab_types.id
+    LEFT JOIN central_park_weather_observations_raw weather
+        ON weather.date = trips.pickup_datetime::date
+    LEFT JOIN nyct2010 pick_up
+        ON pick_up.gid = trips.pickup_nyct2010_gid
+    LEFT JOIN nyct2010 drop_off
+        ON drop_off.gid = trips.dropoff_nyct2010_gid
+) TO '/opt/milovidov/nyc-taxi-data/trips.tsv';
+```
+
+The data snapshot is created at a speed of about 50 MB per second. While creating the snapshot, PostgreSQL reads from the disk at a speed of about 28 MB per second.
+This takes about 5 hours. The resulting TSV file is 590612904969 bytes.
+
+Create a temporary table in ClickHouse:
+
+``` sql
+CREATE TABLE trips
+(
+trip_id                 UInt32,
+vendor_id               String,
+pickup_datetime         DateTime,
+dropoff_datetime        Nullable(DateTime),
+store_and_fwd_flag      Nullable(FixedString(1)),
+rate_code_id            Nullable(UInt8),
+pickup_longitude        Nullable(Float64),
+pickup_latitude         Nullable(Float64),
+dropoff_longitude       Nullable(Float64),
+dropoff_latitude        Nullable(Float64),
+passenger_count         Nullable(UInt8),
+trip_distance           Nullable(Float64),
+fare_amount             Nullable(Float32),
+extra                   Nullable(Float32),
+mta_tax                 Nullable(Float32),
+tip_amount              Nullable(Float32),
+tolls_amount            Nullable(Float32),
+ehail_fee               Nullable(Float32),
+improvement_surcharge   Nullable(Float32),
+total_amount            Nullable(Float32),
+payment_type            Nullable(String),
+trip_type               Nullable(UInt8),
+pickup                  Nullable(String),
+dropoff                 Nullable(String),
+cab_type                Nullable(String),
+precipitation           Nullable(UInt8),
+snow_depth              Nullable(UInt8),
+snowfall                Nullable(UInt8),
+max_temperature         Nullable(UInt8),
+min_temperature         Nullable(UInt8),
+average_wind_speed      Nullable(UInt8),
+pickup_nyct2010_gid     Nullable(UInt8),
+pickup_ctlabel          Nullable(String),
+pickup_borocode         Nullable(UInt8),
+pickup_boroname         Nullable(String),
+pickup_ct2010           Nullable(String),
+pickup_boroct2010       Nullable(String),
+pickup_cdeligibil       Nullable(FixedString(1)),
+pickup_ntacode          Nullable(String),
+pickup_ntaname          Nullable(String),
+pickup_puma             Nullable(String),
+dropoff_nyct2010_gid    Nullable(UInt8),
+dropoff_ctlabel         Nullable(String),
+dropoff_borocode        Nullable(UInt8),
+dropoff_boroname        Nullable(String),
+dropoff_ct2010          Nullable(String),
+dropoff_boroct2010      Nullable(String),
+dropoff_cdeligibil      Nullable(String),
+dropoff_ntacode         Nullable(String),
+dropoff_ntaname         Nullable(String),
+dropoff_puma            Nullable(String)
+) ENGINE = Log;
+```
+
+It is needed for converting fields to more correct data types and, if possible, to eliminate NULLs.
+
+``` bash
+$ time clickhouse-client --query="INSERT INTO trips FORMAT TabSeparated" < trips.tsv
+
+real    75m56.214s
+```
+
+Data is read at a speed of 112-140 Mb/second.
+Loading data into a Log type table in one stream took 76 minutes.
+The data in this table uses 142 GB.
+
+(Importing data directly from Postgres is also possible using `COPY ... TO PROGRAM`.)
+
+Unfortunately, all the fields associated with the weather (precipitation…average_wind_speed) were filled with NULL. Because of this, we will remove them from the final data set.
+
+To start, we’ll create a table on a single server. Later we will make the table distributed.
+
+Create and populate a summary table:
+
+``` sql
+CREATE TABLE trips_mergetree
+ENGINE = MergeTree(pickup_date, pickup_datetime, 8192)
+AS SELECT
+
+trip_id,
+CAST(vendor_id AS Enum8('1' = 1, '2' = 2, 'CMT' = 3, 'VTS' = 4, 'DDS' = 5, 'B02512' = 10, 'B02598' = 11, 'B02617' = 12, 'B02682' = 13, 'B02764' = 14)) AS vendor_id,
+toDate(pickup_datetime) AS pickup_date,
+ifNull(pickup_datetime, toDateTime(0)) AS pickup_datetime,
+toDate(dropoff_datetime) AS dropoff_date,
+ifNull(dropoff_datetime, toDateTime(0)) AS dropoff_datetime,
+assumeNotNull(store_and_fwd_flag) IN ('Y', '1', '2') AS store_and_fwd_flag,
+assumeNotNull(rate_code_id) AS rate_code_id,
+assumeNotNull(pickup_longitude) AS pickup_longitude,
+assumeNotNull(pickup_latitude) AS pickup_latitude,
+assumeNotNull(dropoff_longitude) AS dropoff_longitude,
+assumeNotNull(dropoff_latitude) AS dropoff_latitude,
+assumeNotNull(passenger_count) AS passenger_count,
+assumeNotNull(trip_distance) AS trip_distance,
+assumeNotNull(fare_amount) AS fare_amount,
+assumeNotNull(extra) AS extra,
+assumeNotNull(mta_tax) AS mta_tax,
+assumeNotNull(tip_amount) AS tip_amount,
+assumeNotNull(tolls_amount) AS tolls_amount,
+assumeNotNull(ehail_fee) AS ehail_fee,
+assumeNotNull(improvement_surcharge) AS improvement_surcharge,
+assumeNotNull(total_amount) AS total_amount,
+CAST((assumeNotNull(payment_type) AS pt) IN ('CSH', 'CASH', 'Cash', 'CAS', 'Cas', '1') ? 'CSH' : (pt IN ('CRD', 'Credit', 'Cre', 'CRE', 'CREDIT', '2') ? 'CRE' : (pt IN ('NOC', 'No Charge', 'No', '3') ? 'NOC' : (pt IN ('DIS', 'Dispute', 'Dis', '4') ? 'DIS' : 'UNK'))) AS Enum8('CSH' = 1, 'CRE' = 2, 'UNK' = 0, 'NOC' = 3, 'DIS' = 4)) AS payment_type_,
+assumeNotNull(trip_type) AS trip_type,
+ifNull(toFixedString(unhex(pickup), 25), toFixedString('', 25)) AS pickup,
+ifNull(toFixedString(unhex(dropoff), 25), toFixedString('', 25)) AS dropoff,
+CAST(assumeNotNull(cab_type) AS Enum8('yellow' = 1, 'green' = 2, 'uber' = 3)) AS cab_type,
+
+assumeNotNull(pickup_nyct2010_gid) AS pickup_nyct2010_gid,
+toFloat32(ifNull(pickup_ctlabel, '0')) AS pickup_ctlabel,
+assumeNotNull(pickup_borocode) AS pickup_borocode,
+CAST(assumeNotNull(pickup_boroname) AS Enum8('Manhattan' = 1, 'Queens' = 4, 'Brooklyn' = 3, '' = 0, 'Bronx' = 2, 'Staten Island' = 5)) AS pickup_boroname,
+toFixedString(ifNull(pickup_ct2010, '000000'), 6) AS pickup_ct2010,
+toFixedString(ifNull(pickup_boroct2010, '0000000'), 7) AS pickup_boroct2010,
+CAST(assumeNotNull(ifNull(pickup_cdeligibil, ' ')) AS Enum8(' ' = 0, 'E' = 1, 'I' = 2)) AS pickup_cdeligibil,
+toFixedString(ifNull(pickup_ntacode, '0000'), 4) AS pickup_ntacode,
+
+CAST(assumeNotNull(pickup_ntaname) AS Enum16('' = 0, 'Airport' = 1, 'Allerton-Pelham Gardens' = 2, 'Annadale-Huguenot-Prince\'s Bay-Eltingville' = 3, 'Arden Heights' = 4, 'Astoria' = 5, 'Auburndale' = 6, 'Baisley Park' = 7, 'Bath Beach' = 8, 'Battery Park City-Lower Manhattan' = 9, 'Bay Ridge' = 10, 'Bayside-Bayside Hills' = 11, 'Bedford' = 12, 'Bedford Park-Fordham North' = 13, 'Bellerose' = 14, 'Belmont' = 15, 'Bensonhurst East' = 16, 'Bensonhurst West' = 17, 'Borough Park' = 18, 'Breezy Point-Belle Harbor-Rockaway Park-Broad Channel' = 19, 'Briarwood-Jamaica Hills' = 20, 'Brighton Beach' = 21, 'Bronxdale' = 22, 'Brooklyn Heights-Cobble Hill' = 23, 'Brownsville' = 24, 'Bushwick North' = 25, 'Bushwick South' = 26, 'Cambria Heights' = 27, 'Canarsie' = 28, 'Carroll Gardens-Columbia Street-Red Hook' = 29, 'Central Harlem North-Polo Grounds' = 30, 'Central Harlem South' = 31, 'Charleston-Richmond Valley-Tottenville' = 32, 'Chinatown' = 33, 'Claremont-Bathgate' = 34, 'Clinton' = 35, 'Clinton Hill' = 36, 'Co-op City' = 37, 'College Point' = 38, 'Corona' = 39, 'Crotona Park East' = 40, 'Crown Heights North' = 41, 'Crown Heights South' = 42, 'Cypress Hills-City Line' = 43, 'DUMBO-Vinegar Hill-Downtown Brooklyn-Boerum Hill' = 44, 'Douglas Manor-Douglaston-Little Neck' = 45, 'Dyker Heights' = 46, 'East Concourse-Concourse Village' = 47, 'East Elmhurst' = 48, 'East Flatbush-Farragut' = 49, 'East Flushing' = 50, 'East Harlem North' = 51, 'East Harlem South' = 52, 'East New York' = 53, 'East New York (Pennsylvania Ave)' = 54, 'East Tremont' = 55, 'East Village' = 56, 'East Williamsburg' = 57, 'Eastchester-Edenwald-Baychester' = 58, 'Elmhurst' = 59, 'Elmhurst-Maspeth' = 60, 'Erasmus' = 61, 'Far Rockaway-Bayswater' = 62, 'Flatbush' = 63, 'Flatlands' = 64, 'Flushing' = 65, 'Fordham South' = 66, 'Forest Hills' = 67, 'Fort Greene' = 68, 'Fresh Meadows-Utopia' = 69, 'Ft. Totten-Bay Terrace-Clearview' = 70, 'Georgetown-Marine Park-Bergen Beach-Mill Basin' = 71, 'Glen Oaks-Floral Park-New Hyde Park' = 72, 'Glendale' = 73, 'Gramercy' = 74, 'Grasmere-Arrochar-Ft. Wadsworth' = 75, 'Gravesend' = 76, 'Great Kills' = 77, 'Greenpoint' = 78, 'Grymes Hill-Clifton-Fox Hills' = 79, 'Hamilton Heights' = 80, 'Hammels-Arverne-Edgemere' = 81, 'Highbridge' = 82, 'Hollis' = 83, 'Homecrest' = 84, 'Hudson Yards-Chelsea-Flatiron-Union Square' = 85, 'Hunters Point-Sunnyside-West Maspeth' = 86, 'Hunts Point' = 87, 'Jackson Heights' = 88, 'Jamaica' = 89, 'Jamaica Estates-Holliswood' = 90, 'Kensington-Ocean Parkway' = 91, 'Kew Gardens' = 92, 'Kew Gardens Hills' = 93, 'Kingsbridge Heights' = 94, 'Laurelton' = 95, 'Lenox Hill-Roosevelt Island' = 96, 'Lincoln Square' = 97, 'Lindenwood-Howard Beach' = 98, 'Longwood' = 99, 'Lower East Side' = 100, 'Madison' = 101, 'Manhattanville' = 102, 'Marble Hill-Inwood' = 103, 'Mariner\'s Harbor-Arlington-Port Ivory-Graniteville' = 104, 'Maspeth' = 105, 'Melrose South-Mott Haven North' = 106, 'Middle Village' = 107, 'Midtown-Midtown South' = 108, 'Midwood' = 109, 'Morningside Heights' = 110, 'Morrisania-Melrose' = 111, 'Mott Haven-Port Morris' = 112, 'Mount Hope' = 113, 'Murray Hill' = 114, 'Murray Hill-Kips Bay' = 115, 'New Brighton-Silver Lake' = 116, 'New Dorp-Midland Beach' = 117, 'New Springville-Bloomfield-Travis' = 118, 'North Corona' = 119, 'North Riverdale-Fieldston-Riverdale' = 120, 'North Side-South Side' = 121, 'Norwood' = 122, 'Oakland Gardens' = 123, 'Oakwood-Oakwood Beach' = 124, 'Ocean Hill' = 125, 'Ocean Parkway South' = 126, 'Old Astoria' = 127, 'Old Town-Dongan Hills-South Beach' = 128, 'Ozone Park' = 129, 'Park Slope-Gowanus' = 130, 'Parkchester' = 131, 'Pelham Bay-Country Club-City Island' = 132, 'Pelham Parkway' = 133, 'Pomonok-Flushing Heights-Hillcrest' = 134, 'Port Richmond' = 135, 'Prospect Heights' = 136, 'Prospect Lefferts Gardens-Wingate' = 137, 'Queens Village' = 138, 'Queensboro Hill' = 139, 'Queensbridge-Ravenswood-Long Island City' = 140, 'Rego Park' = 141, 'Richmond Hill' = 142, 'Ridgewood' = 143, 'Rikers Island' = 144, 'Rosedale' = 145, 'Rossville-Woodrow' = 146, 'Rugby-Remsen Village' = 147, 'Schuylerville-Throgs Neck-Edgewater Park' = 148, 'Seagate-Coney Island' = 149, 'Sheepshead Bay-Gerritsen Beach-Manhattan Beach' = 150, 'SoHo-TriBeCa-Civic Center-Little Italy' = 151, 'Soundview-Bruckner' = 152, 'Soundview-Castle Hill-Clason Point-Harding Park' = 153, 'South Jamaica' = 154, 'South Ozone Park' = 155, 'Springfield Gardens North' = 156, 'Springfield Gardens South-Brookville' = 157, 'Spuyten Duyvil-Kingsbridge' = 158, 'St. Albans' = 159, 'Stapleton-Rosebank' = 160, 'Starrett City' = 161, 'Steinway' = 162, 'Stuyvesant Heights' = 163, 'Stuyvesant Town-Cooper Village' = 164, 'Sunset Park East' = 165, 'Sunset Park West' = 166, 'Todt Hill-Emerson Hill-Heartland Village-Lighthouse Hill' = 167, 'Turtle Bay-East Midtown' = 168, 'University Heights-Morris Heights' = 169, 'Upper East Side-Carnegie Hill' = 170, 'Upper West Side' = 171, 'Van Cortlandt Village' = 172, 'Van Nest-Morris Park-Westchester Square' = 173, 'Washington Heights North' = 174, 'Washington Heights South' = 175, 'West Brighton' = 176, 'West Concourse' = 177, 'West Farms-Bronx River' = 178, 'West New Brighton-New Brighton-St. George' = 179, 'West Village' = 180, 'Westchester-Unionport' = 181, 'Westerleigh' = 182, 'Whitestone' = 183, 'Williamsbridge-Olinville' = 184, 'Williamsburg' = 185, 'Windsor Terrace' = 186, 'Woodhaven' = 187, 'Woodlawn-Wakefield' = 188, 'Woodside' = 189, 'Yorkville' = 190, 'park-cemetery-etc-Bronx' = 191, 'park-cemetery-etc-Brooklyn' = 192, 'park-cemetery-etc-Manhattan' = 193, 'park-cemetery-etc-Queens' = 194, 'park-cemetery-etc-Staten Island' = 195)) AS pickup_ntaname,
+
+toUInt16(ifNull(pickup_puma, '0')) AS pickup_puma,
+
+assumeNotNull(dropoff_nyct2010_gid) AS dropoff_nyct2010_gid,
+toFloat32(ifNull(dropoff_ctlabel, '0')) AS dropoff_ctlabel,
+assumeNotNull(dropoff_borocode) AS dropoff_borocode,
+CAST(assumeNotNull(dropoff_boroname) AS Enum8('Manhattan' = 1, 'Queens' = 4, 'Brooklyn' = 3, '' = 0, 'Bronx' = 2, 'Staten Island' = 5)) AS dropoff_boroname,
+toFixedString(ifNull(dropoff_ct2010, '000000'), 6) AS dropoff_ct2010,
+toFixedString(ifNull(dropoff_boroct2010, '0000000'), 7) AS dropoff_boroct2010,
+CAST(assumeNotNull(ifNull(dropoff_cdeligibil, ' ')) AS Enum8(' ' = 0, 'E' = 1, 'I' = 2)) AS dropoff_cdeligibil,
+toFixedString(ifNull(dropoff_ntacode, '0000'), 4) AS dropoff_ntacode,
+
+CAST(assumeNotNull(dropoff_ntaname) AS Enum16('' = 0, 'Airport' = 1, 'Allerton-Pelham Gardens' = 2, 'Annadale-Huguenot-Prince\'s Bay-Eltingville' = 3, 'Arden Heights' = 4, 'Astoria' = 5, 'Auburndale' = 6, 'Baisley Park' = 7, 'Bath Beach' = 8, 'Battery Park City-Lower Manhattan' = 9, 'Bay Ridge' = 10, 'Bayside-Bayside Hills' = 11, 'Bedford' = 12, 'Bedford Park-Fordham North' = 13, 'Bellerose' = 14, 'Belmont' = 15, 'Bensonhurst East' = 16, 'Bensonhurst West' = 17, 'Borough Park' = 18, 'Breezy Point-Belle Harbor-Rockaway Park-Broad Channel' = 19, 'Briarwood-Jamaica Hills' = 20, 'Brighton Beach' = 21, 'Bronxdale' = 22, 'Brooklyn Heights-Cobble Hill' = 23, 'Brownsville' = 24, 'Bushwick North' = 25, 'Bushwick South' = 26, 'Cambria Heights' = 27, 'Canarsie' = 28, 'Carroll Gardens-Columbia Street-Red Hook' = 29, 'Central Harlem North-Polo Grounds' = 30, 'Central Harlem South' = 31, 'Charleston-Richmond Valley-Tottenville' = 32, 'Chinatown' = 33, 'Claremont-Bathgate' = 34, 'Clinton' = 35, 'Clinton Hill' = 36, 'Co-op City' = 37, 'College Point' = 38, 'Corona' = 39, 'Crotona Park East' = 40, 'Crown Heights North' = 41, 'Crown Heights South' = 42, 'Cypress Hills-City Line' = 43, 'DUMBO-Vinegar Hill-Downtown Brooklyn-Boerum Hill' = 44, 'Douglas Manor-Douglaston-Little Neck' = 45, 'Dyker Heights' = 46, 'East Concourse-Concourse Village' = 47, 'East Elmhurst' = 48, 'East Flatbush-Farragut' = 49, 'East Flushing' = 50, 'East Harlem North' = 51, 'East Harlem South' = 52, 'East New York' = 53, 'East New York (Pennsylvania Ave)' = 54, 'East Tremont' = 55, 'East Village' = 56, 'East Williamsburg' = 57, 'Eastchester-Edenwald-Baychester' = 58, 'Elmhurst' = 59, 'Elmhurst-Maspeth' = 60, 'Erasmus' = 61, 'Far Rockaway-Bayswater' = 62, 'Flatbush' = 63, 'Flatlands' = 64, 'Flushing' = 65, 'Fordham South' = 66, 'Forest Hills' = 67, 'Fort Greene' = 68, 'Fresh Meadows-Utopia' = 69, 'Ft. Totten-Bay Terrace-Clearview' = 70, 'Georgetown-Marine Park-Bergen Beach-Mill Basin' = 71, 'Glen Oaks-Floral Park-New Hyde Park' = 72, 'Glendale' = 73, 'Gramercy' = 74, 'Grasmere-Arrochar-Ft. Wadsworth' = 75, 'Gravesend' = 76, 'Great Kills' = 77, 'Greenpoint' = 78, 'Grymes Hill-Clifton-Fox Hills' = 79, 'Hamilton Heights' = 80, 'Hammels-Arverne-Edgemere' = 81, 'Highbridge' = 82, 'Hollis' = 83, 'Homecrest' = 84, 'Hudson Yards-Chelsea-Flatiron-Union Square' = 85, 'Hunters Point-Sunnyside-West Maspeth' = 86, 'Hunts Point' = 87, 'Jackson Heights' = 88, 'Jamaica' = 89, 'Jamaica Estates-Holliswood' = 90, 'Kensington-Ocean Parkway' = 91, 'Kew Gardens' = 92, 'Kew Gardens Hills' = 93, 'Kingsbridge Heights' = 94, 'Laurelton' = 95, 'Lenox Hill-Roosevelt Island' = 96, 'Lincoln Square' = 97, 'Lindenwood-Howard Beach' = 98, 'Longwood' = 99, 'Lower East Side' = 100, 'Madison' = 101, 'Manhattanville' = 102, 'Marble Hill-Inwood' = 103, 'Mariner\'s Harbor-Arlington-Port Ivory-Graniteville' = 104, 'Maspeth' = 105, 'Melrose South-Mott Haven North' = 106, 'Middle Village' = 107, 'Midtown-Midtown South' = 108, 'Midwood' = 109, 'Morningside Heights' = 110, 'Morrisania-Melrose' = 111, 'Mott Haven-Port Morris' = 112, 'Mount Hope' = 113, 'Murray Hill' = 114, 'Murray Hill-Kips Bay' = 115, 'New Brighton-Silver Lake' = 116, 'New Dorp-Midland Beach' = 117, 'New Springville-Bloomfield-Travis' = 118, 'North Corona' = 119, 'North Riverdale-Fieldston-Riverdale' = 120, 'North Side-South Side' = 121, 'Norwood' = 122, 'Oakland Gardens' = 123, 'Oakwood-Oakwood Beach' = 124, 'Ocean Hill' = 125, 'Ocean Parkway South' = 126, 'Old Astoria' = 127, 'Old Town-Dongan Hills-South Beach' = 128, 'Ozone Park' = 129, 'Park Slope-Gowanus' = 130, 'Parkchester' = 131, 'Pelham Bay-Country Club-City Island' = 132, 'Pelham Parkway' = 133, 'Pomonok-Flushing Heights-Hillcrest' = 134, 'Port Richmond' = 135, 'Prospect Heights' = 136, 'Prospect Lefferts Gardens-Wingate' = 137, 'Queens Village' = 138, 'Queensboro Hill' = 139, 'Queensbridge-Ravenswood-Long Island City' = 140, 'Rego Park' = 141, 'Richmond Hill' = 142, 'Ridgewood' = 143, 'Rikers Island' = 144, 'Rosedale' = 145, 'Rossville-Woodrow' = 146, 'Rugby-Remsen Village' = 147, 'Schuylerville-Throgs Neck-Edgewater Park' = 148, 'Seagate-Coney Island' = 149, 'Sheepshead Bay-Gerritsen Beach-Manhattan Beach' = 150, 'SoHo-TriBeCa-Civic Center-Little Italy' = 151, 'Soundview-Bruckner' = 152, 'Soundview-Castle Hill-Clason Point-Harding Park' = 153, 'South Jamaica' = 154, 'South Ozone Park' = 155, 'Springfield Gardens North' = 156, 'Springfield Gardens South-Brookville' = 157, 'Spuyten Duyvil-Kingsbridge' = 158, 'St. Albans' = 159, 'Stapleton-Rosebank' = 160, 'Starrett City' = 161, 'Steinway' = 162, 'Stuyvesant Heights' = 163, 'Stuyvesant Town-Cooper Village' = 164, 'Sunset Park East' = 165, 'Sunset Park West' = 166, 'Todt Hill-Emerson Hill-Heartland Village-Lighthouse Hill' = 167, 'Turtle Bay-East Midtown' = 168, 'University Heights-Morris Heights' = 169, 'Upper East Side-Carnegie Hill' = 170, 'Upper West Side' = 171, 'Van Cortlandt Village' = 172, 'Van Nest-Morris Park-Westchester Square' = 173, 'Washington Heights North' = 174, 'Washington Heights South' = 175, 'West Brighton' = 176, 'West Concourse' = 177, 'West Farms-Bronx River' = 178, 'West New Brighton-New Brighton-St. George' = 179, 'West Village' = 180, 'Westchester-Unionport' = 181, 'Westerleigh' = 182, 'Whitestone' = 183, 'Williamsbridge-Olinville' = 184, 'Williamsburg' = 185, 'Windsor Terrace' = 186, 'Woodhaven' = 187, 'Woodlawn-Wakefield' = 188, 'Woodside' = 189, 'Yorkville' = 190, 'park-cemetery-etc-Bronx' = 191, 'park-cemetery-etc-Brooklyn' = 192, 'park-cemetery-etc-Manhattan' = 193, 'park-cemetery-etc-Queens' = 194, 'park-cemetery-etc-Staten Island' = 195)) AS dropoff_ntaname,
+
+toUInt16(ifNull(dropoff_puma, '0')) AS dropoff_puma
+
+FROM trips
+```
+
+This takes 3030 seconds at a speed of about 428,000 rows per second.
+To load it faster, you can create the table with the `Log` engine instead of `MergeTree`. In this case, the download works faster than 200 seconds.
+
+The table uses 126 GB of disk space.
+
+``` sql
+SELECT formatReadableSize(sum(bytes)) FROM system.parts WHERE table = 'trips_mergetree' AND active
+```
+
+``` text
+┌─formatReadableSize(sum(bytes))─┐
+│ 126.18 GiB                     │
+└────────────────────────────────┘
+```
+
+Among other things, you can run the OPTIMIZE query on MergeTree. But it’s not required since everything will be fine without it.
+
+## Download of Prepared Partitions {#download-of-prepared-partitions}
+
+``` bash
+$ curl -O https://datasets.clickhouse.com/trips_mergetree/partitions/trips_mergetree.tar
+$ tar xvf trips_mergetree.tar -C /var/lib/clickhouse # path to ClickHouse data directory
+$ # check permissions of unpacked data, fix if required
+$ sudo service clickhouse-server restart
+$ clickhouse-client --query "select count(*) from datasets.trips_mergetree"
+```
+
+:::info    
+If you will run the queries described below, you have to use the full table name, `datasets.trips_mergetree`.
+:::
+
+## Results on Single Server {#results-on-single-server}
+
+Q1:
+
+``` sql
+SELECT cab_type, count(*) FROM trips_mergetree GROUP BY cab_type
+```
+
+0.490 seconds.
+
+Q2:
+
+``` sql
+SELECT passenger_count, avg(total_amount) FROM trips_mergetree GROUP BY passenger_count
+```
+
+1.224 seconds.
+
+Q3:
+
+``` sql
+SELECT passenger_count, toYear(pickup_date) AS year, count(*) FROM trips_mergetree GROUP BY passenger_count, year
+```
+
+2.104 seconds.
+
+Q4:
+
+``` sql
+SELECT passenger_count, toYear(pickup_date) AS year, round(trip_distance) AS distance, count(*)
+FROM trips_mergetree
+GROUP BY passenger_count, year, distance
+ORDER BY year, count(*) DESC
+```
+
+3.593 seconds.
+
+The following server was used:
+
+Two Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz, 16 physical cores total, 128 GiB RAM, 8x6 TB HD on hardware RAID-5
+
+Execution time is the best of three runs. But starting from the second run, queries read data from the file system cache. No further caching occurs: the data is read out and processed in each run.
+
+Creating a table on three servers:
+
+On each server:
+
+``` sql
+CREATE TABLE default.trips_mergetree_third ( trip_id UInt32,  vendor_id Enum8('1' = 1, '2' = 2, 'CMT' = 3, 'VTS' = 4, 'DDS' = 5, 'B02512' = 10, 'B02598' = 11, 'B02617' = 12, 'B02682' = 13, 'B02764' = 14),  pickup_date Date,  pickup_datetime DateTime,  dropoff_date Date,  dropoff_datetime DateTime,  store_and_fwd_flag UInt8,  rate_code_id UInt8,  pickup_longitude Float64,  pickup_latitude Float64,  dropoff_longitude Float64,  dropoff_latitude Float64,  passenger_count UInt8,  trip_distance Float64,  fare_amount Float32,  extra Float32,  mta_tax Float32,  tip_amount Float32,  tolls_amount Float32,  ehail_fee Float32,  improvement_surcharge Float32,  total_amount Float32,  payment_type_ Enum8('UNK' = 0, 'CSH' = 1, 'CRE' = 2, 'NOC' = 3, 'DIS' = 4),  trip_type UInt8,  pickup FixedString(25),  dropoff FixedString(25),  cab_type Enum8('yellow' = 1, 'green' = 2, 'uber' = 3),  pickup_nyct2010_gid UInt8,  pickup_ctlabel Float32,  pickup_borocode UInt8,  pickup_boroname Enum8('' = 0, 'Manhattan' = 1, 'Bronx' = 2, 'Brooklyn' = 3, 'Queens' = 4, 'Staten Island' = 5),  pickup_ct2010 FixedString(6),  pickup_boroct2010 FixedString(7),  pickup_cdeligibil Enum8(' ' = 0, 'E' = 1, 'I' = 2),  pickup_ntacode FixedString(4),  pickup_ntaname Enum16('' = 0, 'Airport' = 1, 'Allerton-Pelham Gardens' = 2, 'Annadale-Huguenot-Prince\'s Bay-Eltingville' = 3, 'Arden Heights' = 4, 'Astoria' = 5, 'Auburndale' = 6, 'Baisley Park' = 7, 'Bath Beach' = 8, 'Battery Park City-Lower Manhattan' = 9, 'Bay Ridge' = 10, 'Bayside-Bayside Hills' = 11, 'Bedford' = 12, 'Bedford Park-Fordham North' = 13, 'Bellerose' = 14, 'Belmont' = 15, 'Bensonhurst East' = 16, 'Bensonhurst West' = 17, 'Borough Park' = 18, 'Breezy Point-Belle Harbor-Rockaway Park-Broad Channel' = 19, 'Briarwood-Jamaica Hills' = 20, 'Brighton Beach' = 21, 'Bronxdale' = 22, 'Brooklyn Heights-Cobble Hill' = 23, 'Brownsville' = 24, 'Bushwick North' = 25, 'Bushwick South' = 26, 'Cambria Heights' = 27, 'Canarsie' = 28, 'Carroll Gardens-Columbia Street-Red Hook' = 29, 'Central Harlem North-Polo Grounds' = 30, 'Central Harlem South' = 31, 'Charleston-Richmond Valley-Tottenville' = 32, 'Chinatown' = 33, 'Claremont-Bathgate' = 34, 'Clinton' = 35, 'Clinton Hill' = 36, 'Co-op City' = 37, 'College Point' = 38, 'Corona' = 39, 'Crotona Park East' = 40, 'Crown Heights North' = 41, 'Crown Heights South' = 42, 'Cypress Hills-City Line' = 43, 'DUMBO-Vinegar Hill-Downtown Brooklyn-Boerum Hill' = 44, 'Douglas Manor-Douglaston-Little Neck' = 45, 'Dyker Heights' = 46, 'East Concourse-Concourse Village' = 47, 'East Elmhurst' = 48, 'East Flatbush-Farragut' = 49, 'East Flushing' = 50, 'East Harlem North' = 51, 'East Harlem South' = 52, 'East New York' = 53, 'East New York (Pennsylvania Ave)' = 54, 'East Tremont' = 55, 'East Village' = 56, 'East Williamsburg' = 57, 'Eastchester-Edenwald-Baychester' = 58, 'Elmhurst' = 59, 'Elmhurst-Maspeth' = 60, 'Erasmus' = 61, 'Far Rockaway-Bayswater' = 62, 'Flatbush' = 63, 'Flatlands' = 64, 'Flushing' = 65, 'Fordham South' = 66, 'Forest Hills' = 67, 'Fort Greene' = 68, 'Fresh Meadows-Utopia' = 69, 'Ft. Totten-Bay Terrace-Clearview' = 70, 'Georgetown-Marine Park-Bergen Beach-Mill Basin' = 71, 'Glen Oaks-Floral Park-New Hyde Park' = 72, 'Glendale' = 73, 'Gramercy' = 74, 'Grasmere-Arrochar-Ft. Wadsworth' = 75, 'Gravesend' = 76, 'Great Kills' = 77, 'Greenpoint' = 78, 'Grymes Hill-Clifton-Fox Hills' = 79, 'Hamilton Heights' = 80, 'Hammels-Arverne-Edgemere' = 81, 'Highbridge' = 82, 'Hollis' = 83, 'Homecrest' = 84, 'Hudson Yards-Chelsea-Flatiron-Union Square' = 85, 'Hunters Point-Sunnyside-West Maspeth' = 86, 'Hunts Point' = 87, 'Jackson Heights' = 88, 'Jamaica' = 89, 'Jamaica Estates-Holliswood' = 90, 'Kensington-Ocean Parkway' = 91, 'Kew Gardens' = 92, 'Kew Gardens Hills' = 93, 'Kingsbridge Heights' = 94, 'Laurelton' = 95, 'Lenox Hill-Roosevelt Island' = 96, 'Lincoln Square' = 97, 'Lindenwood-Howard Beach' = 98, 'Longwood' = 99, 'Lower East Side' = 100, 'Madison' = 101, 'Manhattanville' = 102, 'Marble Hill-Inwood' = 103, 'Mariner\'s Harbor-Arlington-Port Ivory-Graniteville' = 104, 'Maspeth' = 105, 'Melrose South-Mott Haven North' = 106, 'Middle Village' = 107, 'Midtown-Midtown South' = 108, 'Midwood' = 109, 'Morningside Heights' = 110, 'Morrisania-Melrose' = 111, 'Mott Haven-Port Morris' = 112, 'Mount Hope' = 113, 'Murray Hill' = 114, 'Murray Hill-Kips Bay' = 115, 'New Brighton-Silver Lake' = 116, 'New Dorp-Midland Beach' = 117, 'New Springville-Bloomfield-Travis' = 118, 'North Corona' = 119, 'North Riverdale-Fieldston-Riverdale' = 120, 'North Side-South Side' = 121, 'Norwood' = 122, 'Oakland Gardens' = 123, 'Oakwood-Oakwood Beach' = 124, 'Ocean Hill' = 125, 'Ocean Parkway South' = 126, 'Old Astoria' = 127, 'Old Town-Dongan Hills-South Beach' = 128, 'Ozone Park' = 129, 'Park Slope-Gowanus' = 130, 'Parkchester' = 131, 'Pelham Bay-Country Club-City Island' = 132, 'Pelham Parkway' = 133, 'Pomonok-Flushing Heights-Hillcrest' = 134, 'Port Richmond' = 135, 'Prospect Heights' = 136, 'Prospect Lefferts Gardens-Wingate' = 137, 'Queens Village' = 138, 'Queensboro Hill' = 139, 'Queensbridge-Ravenswood-Long Island City' = 140, 'Rego Park' = 141, 'Richmond Hill' = 142, 'Ridgewood' = 143, 'Rikers Island' = 144, 'Rosedale' = 145, 'Rossville-Woodrow' = 146, 'Rugby-Remsen Village' = 147, 'Schuylerville-Throgs Neck-Edgewater Park' = 148, 'Seagate-Coney Island' = 149, 'Sheepshead Bay-Gerritsen Beach-Manhattan Beach' = 150, 'SoHo-TriBeCa-Civic Center-Little Italy' = 151, 'Soundview-Bruckner' = 152, 'Soundview-Castle Hill-Clason Point-Harding Park' = 153, 'South Jamaica' = 154, 'South Ozone Park' = 155, 'Springfield Gardens North' = 156, 'Springfield Gardens South-Brookville' = 157, 'Spuyten Duyvil-Kingsbridge' = 158, 'St. Albans' = 159, 'Stapleton-Rosebank' = 160, 'Starrett City' = 161, 'Steinway' = 162, 'Stuyvesant Heights' = 163, 'Stuyvesant Town-Cooper Village' = 164, 'Sunset Park East' = 165, 'Sunset Park West' = 166, 'Todt Hill-Emerson Hill-Heartland Village-Lighthouse Hill' = 167, 'Turtle Bay-East Midtown' = 168, 'University Heights-Morris Heights' = 169, 'Upper East Side-Carnegie Hill' = 170, 'Upper West Side' = 171, 'Van Cortlandt Village' = 172, 'Van Nest-Morris Park-Westchester Square' = 173, 'Washington Heights North' = 174, 'Washington Heights South' = 175, 'West Brighton' = 176, 'West Concourse' = 177, 'West Farms-Bronx River' = 178, 'West New Brighton-New Brighton-St. George' = 179, 'West Village' = 180, 'Westchester-Unionport' = 181, 'Westerleigh' = 182, 'Whitestone' = 183, 'Williamsbridge-Olinville' = 184, 'Williamsburg' = 185, 'Windsor Terrace' = 186, 'Woodhaven' = 187, 'Woodlawn-Wakefield' = 188, 'Woodside' = 189, 'Yorkville' = 190, 'park-cemetery-etc-Bronx' = 191, 'park-cemetery-etc-Brooklyn' = 192, 'park-cemetery-etc-Manhattan' = 193, 'park-cemetery-etc-Queens' = 194, 'park-cemetery-etc-Staten Island' = 195),  pickup_puma UInt16,  dropoff_nyct2010_gid UInt8,  dropoff_ctlabel Float32,  dropoff_borocode UInt8,  dropoff_boroname Enum8('' = 0, 'Manhattan' = 1, 'Bronx' = 2, 'Brooklyn' = 3, 'Queens' = 4, 'Staten Island' = 5),  dropoff_ct2010 FixedString(6),  dropoff_boroct2010 FixedString(7),  dropoff_cdeligibil Enum8(' ' = 0, 'E' = 1, 'I' = 2),  dropoff_ntacode FixedString(4),  dropoff_ntaname Enum16('' = 0, 'Airport' = 1, 'Allerton-Pelham Gardens' = 2, 'Annadale-Huguenot-Prince\'s Bay-Eltingville' = 3, 'Arden Heights' = 4, 'Astoria' = 5, 'Auburndale' = 6, 'Baisley Park' = 7, 'Bath Beach' = 8, 'Battery Park City-Lower Manhattan' = 9, 'Bay Ridge' = 10, 'Bayside-Bayside Hills' = 11, 'Bedford' = 12, 'Bedford Park-Fordham North' = 13, 'Bellerose' = 14, 'Belmont' = 15, 'Bensonhurst East' = 16, 'Bensonhurst West' = 17, 'Borough Park' = 18, 'Breezy Point-Belle Harbor-Rockaway Park-Broad Channel' = 19, 'Briarwood-Jamaica Hills' = 20, 'Brighton Beach' = 21, 'Bronxdale' = 22, 'Brooklyn Heights-Cobble Hill' = 23, 'Brownsville' = 24, 'Bushwick North' = 25, 'Bushwick South' = 26, 'Cambria Heights' = 27, 'Canarsie' = 28, 'Carroll Gardens-Columbia Street-Red Hook' = 29, 'Central Harlem North-Polo Grounds' = 30, 'Central Harlem South' = 31, 'Charleston-Richmond Valley-Tottenville' = 32, 'Chinatown' = 33, 'Claremont-Bathgate' = 34, 'Clinton' = 35, 'Clinton Hill' = 36, 'Co-op City' = 37, 'College Point' = 38, 'Corona' = 39, 'Crotona Park East' = 40, 'Crown Heights North' = 41, 'Crown Heights South' = 42, 'Cypress Hills-City Line' = 43, 'DUMBO-Vinegar Hill-Downtown Brooklyn-Boerum Hill' = 44, 'Douglas Manor-Douglaston-Little Neck' = 45, 'Dyker Heights' = 46, 'East Concourse-Concourse Village' = 47, 'East Elmhurst' = 48, 'East Flatbush-Farragut' = 49, 'East Flushing' = 50, 'East Harlem North' = 51, 'East Harlem South' = 52, 'East New York' = 53, 'East New York (Pennsylvania Ave)' = 54, 'East Tremont' = 55, 'East Village' = 56, 'East Williamsburg' = 57, 'Eastchester-Edenwald-Baychester' = 58, 'Elmhurst' = 59, 'Elmhurst-Maspeth' = 60, 'Erasmus' = 61, 'Far Rockaway-Bayswater' = 62, 'Flatbush' = 63, 'Flatlands' = 64, 'Flushing' = 65, 'Fordham South' = 66, 'Forest Hills' = 67, 'Fort Greene' = 68, 'Fresh Meadows-Utopia' = 69, 'Ft. Totten-Bay Terrace-Clearview' = 70, 'Georgetown-Marine Park-Bergen Beach-Mill Basin' = 71, 'Glen Oaks-Floral Park-New Hyde Park' = 72, 'Glendale' = 73, 'Gramercy' = 74, 'Grasmere-Arrochar-Ft. Wadsworth' = 75, 'Gravesend' = 76, 'Great Kills' = 77, 'Greenpoint' = 78, 'Grymes Hill-Clifton-Fox Hills' = 79, 'Hamilton Heights' = 80, 'Hammels-Arverne-Edgemere' = 81, 'Highbridge' = 82, 'Hollis' = 83, 'Homecrest' = 84, 'Hudson Yards-Chelsea-Flatiron-Union Square' = 85, 'Hunters Point-Sunnyside-West Maspeth' = 86, 'Hunts Point' = 87, 'Jackson Heights' = 88, 'Jamaica' = 89, 'Jamaica Estates-Holliswood' = 90, 'Kensington-Ocean Parkway' = 91, 'Kew Gardens' = 92, 'Kew Gardens Hills' = 93, 'Kingsbridge Heights' = 94, 'Laurelton' = 95, 'Lenox Hill-Roosevelt Island' = 96, 'Lincoln Square' = 97, 'Lindenwood-Howard Beach' = 98, 'Longwood' = 99, 'Lower East Side' = 100, 'Madison' = 101, 'Manhattanville' = 102, 'Marble Hill-Inwood' = 103, 'Mariner\'s Harbor-Arlington-Port Ivory-Graniteville' = 104, 'Maspeth' = 105, 'Melrose South-Mott Haven North' = 106, 'Middle Village' = 107, 'Midtown-Midtown South' = 108, 'Midwood' = 109, 'Morningside Heights' = 110, 'Morrisania-Melrose' = 111, 'Mott Haven-Port Morris' = 112, 'Mount Hope' = 113, 'Murray Hill' = 114, 'Murray Hill-Kips Bay' = 115, 'New Brighton-Silver Lake' = 116, 'New Dorp-Midland Beach' = 117, 'New Springville-Bloomfield-Travis' = 118, 'North Corona' = 119, 'North Riverdale-Fieldston-Riverdale' = 120, 'North Side-South Side' = 121, 'Norwood' = 122, 'Oakland Gardens' = 123, 'Oakwood-Oakwood Beach' = 124, 'Ocean Hill' = 125, 'Ocean Parkway South' = 126, 'Old Astoria' = 127, 'Old Town-Dongan Hills-South Beach' = 128, 'Ozone Park' = 129, 'Park Slope-Gowanus' = 130, 'Parkchester' = 131, 'Pelham Bay-Country Club-City Island' = 132, 'Pelham Parkway' = 133, 'Pomonok-Flushing Heights-Hillcrest' = 134, 'Port Richmond' = 135, 'Prospect Heights' = 136, 'Prospect Lefferts Gardens-Wingate' = 137, 'Queens Village' = 138, 'Queensboro Hill' = 139, 'Queensbridge-Ravenswood-Long Island City' = 140, 'Rego Park' = 141, 'Richmond Hill' = 142, 'Ridgewood' = 143, 'Rikers Island' = 144, 'Rosedale' = 145, 'Rossville-Woodrow' = 146, 'Rugby-Remsen Village' = 147, 'Schuylerville-Throgs Neck-Edgewater Park' = 148, 'Seagate-Coney Island' = 149, 'Sheepshead Bay-Gerritsen Beach-Manhattan Beach' = 150, 'SoHo-TriBeCa-Civic Center-Little Italy' = 151, 'Soundview-Bruckner' = 152, 'Soundview-Castle Hill-Clason Point-Harding Park' = 153, 'South Jamaica' = 154, 'South Ozone Park' = 155, 'Springfield Gardens North' = 156, 'Springfield Gardens South-Brookville' = 157, 'Spuyten Duyvil-Kingsbridge' = 158, 'St. Albans' = 159, 'Stapleton-Rosebank' = 160, 'Starrett City' = 161, 'Steinway' = 162, 'Stuyvesant Heights' = 163, 'Stuyvesant Town-Cooper Village' = 164, 'Sunset Park East' = 165, 'Sunset Park West' = 166, 'Todt Hill-Emerson Hill-Heartland Village-Lighthouse Hill' = 167, 'Turtle Bay-East Midtown' = 168, 'University Heights-Morris Heights' = 169, 'Upper East Side-Carnegie Hill' = 170, 'Upper West Side' = 171, 'Van Cortlandt Village' = 172, 'Van Nest-Morris Park-Westchester Square' = 173, 'Washington Heights North' = 174, 'Washington Heights South' = 175, 'West Brighton' = 176, 'West Concourse' = 177, 'West Farms-Bronx River' = 178, 'West New Brighton-New Brighton-St. George' = 179, 'West Village' = 180, 'Westchester-Unionport' = 181, 'Westerleigh' = 182, 'Whitestone' = 183, 'Williamsbridge-Olinville' = 184, 'Williamsburg' = 185, 'Windsor Terrace' = 186, 'Woodhaven' = 187, 'Woodlawn-Wakefield' = 188, 'Woodside' = 189, 'Yorkville' = 190, 'park-cemetery-etc-Bronx' = 191, 'park-cemetery-etc-Brooklyn' = 192, 'park-cemetery-etc-Manhattan' = 193, 'park-cemetery-etc-Queens' = 194, 'park-cemetery-etc-Staten Island' = 195),  dropoff_puma UInt16) ENGINE = MergeTree(pickup_date, pickup_datetime, 8192)
+```
+
+On the source server:
+
+``` sql
+CREATE TABLE trips_mergetree_x3 AS trips_mergetree_third ENGINE = Distributed(perftest, default, trips_mergetree_third, rand())
+```
+
+The following query redistributes data:
+
+``` sql
+INSERT INTO trips_mergetree_x3 SELECT * FROM trips_mergetree
+```
+
+This takes 2454 seconds.
+
+On three servers:
+
+Q1: 0.212 seconds.
+Q2: 0.438 seconds.
+Q3: 0.733 seconds.
+Q4: 1.241 seconds.
+
+No surprises here, since the queries are scaled linearly.
+
+We also have the results from a cluster of 140 servers:
+
+Q1: 0.028 sec.
+Q2: 0.043 sec.
+Q3: 0.051 sec.
+Q4: 0.072 sec.
+
+In this case, the query processing time is determined above all by network latency.
+We ran queries using a client located in a different datacenter than where the cluster was located, which added about 20 ms of latency.
+
+## Summary {#summary}
+
+| servers | Q1    | Q2    | Q3    | Q4    |
+|---------|-------|-------|-------|-------|
+| 1, E5-2650v2          | 0.490 | 1.224 | 2.104 | 3.593 |
+| 3, E5-2650v2          | 0.212 | 0.438 | 0.733 | 1.241 |
+| 1, AWS c5n.4xlarge    | 0.249 | 1.279 | 1.738 | 3.527 |
+| 1, AWS c5n.9xlarge    | 0.130 | 0.584 | 0.777 | 1.811 |
+| 3, AWS c5n.9xlarge    | 0.057 | 0.231 | 0.285 | 0.641 |
+| 140, E5-2650v2        | 0.028 | 0.043 | 0.051 | 0.072 |
+
+[Original article](https://clickhouse.com/docs/en/getting_started/example_datasets/nyc_taxi/) <!--hide-->
diff --git a/docs/en/reference/getting-started/example-datasets/ontime.md b/docs/en/reference/getting-started/example-datasets/ontime.md
new file mode 100644
index 00000000000..bb3c3644972
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/ontime.md
@@ -0,0 +1,408 @@
+---
+sidebar_label: OnTime Airline Flight Data
+description: Dataset containing the on-time performance of airline flights
+---
+
+# OnTime 
+
+This dataset can be obtained in two ways:
+
+-   import from raw data
+-   download of prepared partitions
+
+## Import from Raw Data {#import-from-raw-data}
+
+Downloading data:
+
+``` bash
+wget --no-check-certificate --continue https://transtats.bts.gov/PREZIP/On_Time_Reporting_Carrier_On_Time_Performance_1987_present_{1987..2021}_{1..12}.zip
+```
+
+Creating a table:
+
+``` sql
+CREATE TABLE `ontime`
+(
+    `Year`                            UInt16,
+    `Quarter`                         UInt8,
+    `Month`                           UInt8,
+    `DayofMonth`                      UInt8,
+    `DayOfWeek`                       UInt8,
+    `FlightDate`                      Date,
+    `Reporting_Airline`               String,
+    `DOT_ID_Reporting_Airline`        Int32,
+    `IATA_CODE_Reporting_Airline`     String,
+    `Tail_Number`                     String,
+    `Flight_Number_Reporting_Airline` String,
+    `OriginAirportID`                 Int32,
+    `OriginAirportSeqID`              Int32,
+    `OriginCityMarketID`              Int32,
+    `Origin`                          FixedString(5),
+    `OriginCityName`                  String,
+    `OriginState`                     FixedString(2),
+    `OriginStateFips`                 String,
+    `OriginStateName`                 String,
+    `OriginWac`                       Int32,
+    `DestAirportID`                   Int32,
+    `DestAirportSeqID`                Int32,
+    `DestCityMarketID`                Int32,
+    `Dest`                            FixedString(5),
+    `DestCityName`                    String,
+    `DestState`                       FixedString(2),
+    `DestStateFips`                   String,
+    `DestStateName`                   String,
+    `DestWac`                         Int32,
+    `CRSDepTime`                      Int32,
+    `DepTime`                         Int32,
+    `DepDelay`                        Int32,
+    `DepDelayMinutes`                 Int32,
+    `DepDel15`                        Int32,
+    `DepartureDelayGroups`            String,
+    `DepTimeBlk`                      String,
+    `TaxiOut`                         Int32,
+    `WheelsOff`                       Int32,
+    `WheelsOn`                        Int32,
+    `TaxiIn`                          Int32,
+    `CRSArrTime`                      Int32,
+    `ArrTime`                         Int32,
+    `ArrDelay`                        Int32,
+    `ArrDelayMinutes`                 Int32,
+    `ArrDel15`                        Int32,
+    `ArrivalDelayGroups`              Int32,
+    `ArrTimeBlk`                      String,
+    `Cancelled`                       UInt8,
+    `CancellationCode`                FixedString(1),
+    `Diverted`                        UInt8,
+    `CRSElapsedTime`                  Int32,
+    `ActualElapsedTime`               Int32,
+    `AirTime`                         Nullable(Int32),
+    `Flights`                         Int32,
+    `Distance`                        Int32,
+    `DistanceGroup`                   UInt8,
+    `CarrierDelay`                    Int32,
+    `WeatherDelay`                    Int32,
+    `NASDelay`                        Int32,
+    `SecurityDelay`                   Int32,
+    `LateAircraftDelay`               Int32,
+    `FirstDepTime`                    String,
+    `TotalAddGTime`                   String,
+    `LongestAddGTime`                 String,
+    `DivAirportLandings`              String,
+    `DivReachedDest`                  String,
+    `DivActualElapsedTime`            String,
+    `DivArrDelay`                     String,
+    `DivDistance`                     String,
+    `Div1Airport`                     String,
+    `Div1AirportID`                   Int32,
+    `Div1AirportSeqID`                Int32,
+    `Div1WheelsOn`                    String,
+    `Div1TotalGTime`                  String,
+    `Div1LongestGTime`                String,
+    `Div1WheelsOff`                   String,
+    `Div1TailNum`                     String,
+    `Div2Airport`                     String,
+    `Div2AirportID`                   Int32,
+    `Div2AirportSeqID`                Int32,
+    `Div2WheelsOn`                    String,
+    `Div2TotalGTime`                  String,
+    `Div2LongestGTime`                String,
+    `Div2WheelsOff`                   String,
+    `Div2TailNum`                     String,
+    `Div3Airport`                     String,
+    `Div3AirportID`                   Int32,
+    `Div3AirportSeqID`                Int32,
+    `Div3WheelsOn`                    String,
+    `Div3TotalGTime`                  String,
+    `Div3LongestGTime`                String,
+    `Div3WheelsOff`                   String,
+    `Div3TailNum`                     String,
+    `Div4Airport`                     String,
+    `Div4AirportID`                   Int32,
+    `Div4AirportSeqID`                Int32,
+    `Div4WheelsOn`                    String,
+    `Div4TotalGTime`                  String,
+    `Div4LongestGTime`                String,
+    `Div4WheelsOff`                   String,
+    `Div4TailNum`                     String,
+    `Div5Airport`                     String,
+    `Div5AirportID`                   Int32,
+    `Div5AirportSeqID`                Int32,
+    `Div5WheelsOn`                    String,
+    `Div5TotalGTime`                  String,
+    `Div5LongestGTime`                String,
+    `Div5WheelsOff`                   String,
+    `Div5TailNum`                     String
+) ENGINE = MergeTree
+      PARTITION BY Year
+      ORDER BY (IATA_CODE_Reporting_Airline, FlightDate)
+      SETTINGS index_granularity = 8192;
+```
+
+Loading data with multiple threads:
+
+``` bash
+ls -1 *.zip | xargs -I{} -P $(nproc) bash -c "echo {}; unzip -cq {} '*.csv' | sed 's/\.00//g' | clickhouse-client --input_format_with_names_use_header=0 --query='INSERT INTO ontime FORMAT CSVWithNames'"
+```
+
+(if you will have memory shortage or other issues on your server, remove the `-P $(nproc)` part)
+
+## Download of Prepared Partitions {#download-of-prepared-partitions}
+
+``` bash
+$ curl -O https://datasets.clickhouse.com/ontime/partitions/ontime.tar
+$ tar xvf ontime.tar -C /var/lib/clickhouse # path to ClickHouse data directory
+$ # check permissions of unpacked data, fix if required
+$ sudo service clickhouse-server restart
+$ clickhouse-client --query "select count(*) from datasets.ontime"
+```
+
+:::note    
+If you will run the queries described below, you have to use the full table name, `datasets.ontime`.
+:::
+
+## Queries {#queries}
+
+Q0.
+
+``` sql
+SELECT avg(c1)
+FROM
+(
+    SELECT Year, Month, count(*) AS c1
+    FROM ontime
+    GROUP BY Year, Month
+);
+```
+
+Q1. The number of flights per day from the year 2000 to 2008
+
+``` sql
+SELECT DayOfWeek, count(*) AS c
+FROM ontime
+WHERE Year>=2000 AND Year<=2008
+GROUP BY DayOfWeek
+ORDER BY c DESC;
+```
+
+Q2. The number of flights delayed by more than 10 minutes, grouped by the day of the week, for 2000-2008
+
+``` sql
+SELECT DayOfWeek, count(*) AS c
+FROM ontime
+WHERE DepDelay>10 AND Year>=2000 AND Year<=2008
+GROUP BY DayOfWeek
+ORDER BY c DESC;
+```
+
+Q3. The number of delays by the airport for 2000-2008
+
+``` sql
+SELECT Origin, count(*) AS c
+FROM ontime
+WHERE DepDelay>10 AND Year>=2000 AND Year<=2008
+GROUP BY Origin
+ORDER BY c DESC
+LIMIT 10;
+```
+
+Q4. The number of delays by carrier for 2007
+
+``` sql
+SELECT IATA_CODE_Reporting_Airline AS Carrier, count(*)
+FROM ontime
+WHERE DepDelay>10 AND Year=2007
+GROUP BY Carrier
+ORDER BY count(*) DESC;
+```
+
+Q5. The percentage of delays by carrier for 2007
+
+``` sql
+SELECT Carrier, c, c2, c*100/c2 as c3
+FROM
+(
+    SELECT
+        IATA_CODE_Reporting_Airline AS Carrier,
+        count(*) AS c
+    FROM ontime
+    WHERE DepDelay>10
+        AND Year=2007
+    GROUP BY Carrier
+) q
+JOIN
+(
+    SELECT
+        IATA_CODE_Reporting_Airline AS Carrier,
+        count(*) AS c2
+    FROM ontime
+    WHERE Year=2007
+    GROUP BY Carrier
+) qq USING Carrier
+ORDER BY c3 DESC;
+```
+
+Better version of the same query:
+
+``` sql
+SELECT IATA_CODE_Reporting_Airline AS Carrier, avg(DepDelay>10)*100 AS c3
+FROM ontime
+WHERE Year=2007
+GROUP BY Carrier
+ORDER BY c3 DESC
+```
+
+Q6. The previous request for a broader range of years, 2000-2008
+
+``` sql
+SELECT Carrier, c, c2, c*100/c2 as c3
+FROM
+(
+    SELECT
+        IATA_CODE_Reporting_Airline AS Carrier,
+        count(*) AS c
+    FROM ontime
+    WHERE DepDelay>10
+        AND Year>=2000 AND Year<=2008
+    GROUP BY Carrier
+) q
+JOIN
+(
+    SELECT
+        IATA_CODE_Reporting_Airline AS Carrier,
+        count(*) AS c2
+    FROM ontime
+    WHERE Year>=2000 AND Year<=2008
+    GROUP BY Carrier
+) qq USING Carrier
+ORDER BY c3 DESC;
+```
+
+Better version of the same query:
+
+``` sql
+SELECT IATA_CODE_Reporting_Airline AS Carrier, avg(DepDelay>10)*100 AS c3
+FROM ontime
+WHERE Year>=2000 AND Year<=2008
+GROUP BY Carrier
+ORDER BY c3 DESC;
+```
+
+Q7. Percentage of flights delayed for more than 10 minutes, by year
+
+``` sql
+SELECT Year, c1/c2
+FROM
+(
+    select
+        Year,
+        count(*)*100 as c1
+    from ontime
+    WHERE DepDelay>10
+    GROUP BY Year
+) q
+JOIN
+(
+    select
+        Year,
+        count(*) as c2
+    from ontime
+    GROUP BY Year
+) qq USING (Year)
+ORDER BY Year;
+```
+
+Better version of the same query:
+
+``` sql
+SELECT Year, avg(DepDelay>10)*100
+FROM ontime
+GROUP BY Year
+ORDER BY Year;
+```
+
+Q8. The most popular destinations by the number of directly connected cities for various year ranges
+
+``` sql
+SELECT DestCityName, uniqExact(OriginCityName) AS u
+FROM ontime
+WHERE Year >= 2000 and Year <= 2010
+GROUP BY DestCityName
+ORDER BY u DESC LIMIT 10;
+```
+
+Q9.
+
+``` sql
+SELECT Year, count(*) AS c1
+FROM ontime
+GROUP BY Year;
+```
+
+Q10.
+
+``` sql
+SELECT
+   min(Year), max(Year), IATA_CODE_Reporting_Airline AS Carrier, count(*) AS cnt,
+   sum(ArrDelayMinutes>30) AS flights_delayed,
+   round(sum(ArrDelayMinutes>30)/count(*),2) AS rate
+FROM ontime
+WHERE
+   DayOfWeek NOT IN (6,7) AND OriginState NOT IN ('AK', 'HI', 'PR', 'VI')
+   AND DestState NOT IN ('AK', 'HI', 'PR', 'VI')
+   AND FlightDate < '2010-01-01'
+GROUP by Carrier
+HAVING cnt>100000 and max(Year)>1990
+ORDER by rate DESC
+LIMIT 1000;
+```
+
+Bonus:
+
+``` sql
+SELECT avg(cnt)
+FROM
+(
+    SELECT Year,Month,count(*) AS cnt
+    FROM ontime
+    WHERE DepDel15=1
+    GROUP BY Year,Month
+);
+
+SELECT avg(c1) FROM
+(
+    SELECT Year,Month,count(*) AS c1
+    FROM ontime
+    GROUP BY Year,Month
+);
+
+SELECT DestCityName, uniqExact(OriginCityName) AS u
+FROM ontime
+GROUP BY DestCityName
+ORDER BY u DESC
+LIMIT 10;
+
+SELECT OriginCityName, DestCityName, count() AS c
+FROM ontime
+GROUP BY OriginCityName, DestCityName
+ORDER BY c DESC
+LIMIT 10;
+
+SELECT OriginCityName, count() AS c
+FROM ontime
+GROUP BY OriginCityName
+ORDER BY c DESC
+LIMIT 10;
+```
+
+You can also play with the data in Playground, [example](https://gh-api.clickhouse.com/play?user=play#U0VMRUNUIERheU9mV2VlaywgY291bnQoKikgQVMgYwpGUk9NIG9udGltZQpXSEVSRSBZZWFyPj0yMDAwIEFORCBZZWFyPD0yMDA4CkdST1VQIEJZIERheU9mV2VlawpPUkRFUiBCWSBjIERFU0M7Cg==).
+
+This performance test was created by Vadim Tkachenko. See:
+
+-   https://www.percona.com/blog/2009/10/02/analyzing-air-traffic-performance-with-infobright-and-monetdb/
+-   https://www.percona.com/blog/2009/10/26/air-traffic-queries-in-luciddb/
+-   https://www.percona.com/blog/2009/11/02/air-traffic-queries-in-infinidb-early-alpha/
+-   https://www.percona.com/blog/2014/04/21/using-apache-hadoop-and-impala-together-with-mysql-for-data-analysis/
+-   https://www.percona.com/blog/2016/01/07/apache-spark-with-air-ontime-performance-data/
+-   http://nickmakos.blogspot.ru/2012/08/analyzing-air-traffic-performance-with.html
+
+[Original article](https://clickhouse.com/docs/en/getting_started/example_datasets/ontime/) <!--hide-->
diff --git a/docs/en/reference/getting-started/example-datasets/opensky.md b/docs/en/reference/getting-started/example-datasets/opensky.md
new file mode 100644
index 00000000000..719f32d7c3e
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/opensky.md
@@ -0,0 +1,420 @@
+---
+sidebar_label: Air Traffic Data
+description: The data in this dataset is derived and cleaned from the full OpenSky dataset to illustrate the development of air traffic during the COVID-19 pandemic. 
+---
+
+# Crowdsourced air traffic data from The OpenSky Network 2020
+
+The data in this dataset is derived and cleaned from the full OpenSky dataset to illustrate the development of air traffic during the COVID-19 pandemic. It spans all flights seen by the network's more than 2500 members since 1 January 2019. More data will be periodically included in the dataset until the end of the COVID-19 pandemic.
+
+Source: https://zenodo.org/record/5092942#.YRBCyTpRXYd
+
+Martin Strohmeier, Xavier Olive, Jannis Lübbe, Matthias Schäfer, and Vincent Lenders
+"Crowdsourced air traffic data from the OpenSky Network 2019–2020"
+Earth System Science Data 13(2), 2021
+https://doi.org/10.5194/essd-13-357-2021
+
+## Download the Dataset {#download-dataset}
+
+Run the command:
+
+```bash
+wget -O- https://zenodo.org/record/5092942 | grep -oP 'https://zenodo.org/record/5092942/files/flightlist_\d+_\d+\.csv\.gz' | xargs wget
+```
+
+Download will take about 2 minutes with good internet connection. There are 30 files with total size of 4.3 GB.
+
+## Create the Table {#create-table}
+
+```sql
+CREATE TABLE opensky
+(
+    callsign String,
+    number String,
+    icao24 String,
+    registration String,
+    typecode String,
+    origin String,
+    destination String,
+    firstseen DateTime,
+    lastseen DateTime,
+    day DateTime,
+    latitude_1 Float64,
+    longitude_1 Float64,
+    altitude_1 Float64,
+    latitude_2 Float64,
+    longitude_2 Float64,
+    altitude_2 Float64
+) ENGINE = MergeTree ORDER BY (origin, destination, callsign);
+```
+
+## Import Data {#import-data}
+
+Upload data into ClickHouse in parallel:
+
+```bash
+ls -1 flightlist_*.csv.gz | xargs -P100 -I{} bash -c 'gzip -c -d "{}" | clickhouse-client --date_time_input_format best_effort --query "INSERT INTO opensky FORMAT CSVWithNames"'
+```
+
+- Here we pass the list of files (`ls -1 flightlist_*.csv.gz`) to `xargs` for parallel processing.
+`xargs -P100` specifies to use up to 100 parallel workers but as we only have 30 files, the number of workers will be only 30.
+- For every file, `xargs` will run a script with `bash -c`. The script has substitution in form of `{}` and the `xargs` command will substitute the filename to it (we have asked it for `xargs` with `-I{}`).
+- The script will decompress the file (`gzip -c -d "{}"`) to standard output (`-c` parameter) and the output is redirected to `clickhouse-client`.
+- We also asked to parse [DateTime](../sql-reference/data-types/datetime.md) fields with extended parser ([--date_time_input_format best_effort](../operations/settings/settings.md#settings-date_time_input_format)) to recognize ISO-8601 format with timezone offsets.
+
+Finally, `clickhouse-client` will do insertion. It will read input data in [CSVWithNames](../interfaces/formats.md#csvwithnames) format. 
+
+Parallel upload takes 24 seconds.
+
+If you don't like parallel upload, here is sequential variant:
+
+```bash
+for file in flightlist_*.csv.gz; do gzip -c -d "$file" | clickhouse-client --date_time_input_format best_effort --query "INSERT INTO opensky FORMAT CSVWithNames"; done
+```
+
+## Validate the Data {#validate-data}
+
+Query:
+
+```sql
+SELECT count() FROM opensky;
+```
+
+Result:
+
+```text
+┌──count()─┐
+│ 66010819 │
+└──────────┘
+```
+
+The size of dataset in ClickHouse is just 2.66 GiB, check it.
+
+Query:
+
+```sql
+SELECT formatReadableSize(total_bytes) FROM system.tables WHERE name = 'opensky';
+```
+
+Result:
+
+```text
+┌─formatReadableSize(total_bytes)─┐
+│ 2.66 GiB                        │
+└─────────────────────────────────┘
+```
+
+## Run Some Queries {#run-queries}
+
+Total distance travelled is 68 billion kilometers.
+
+Query:
+
+```sql
+SELECT formatReadableQuantity(sum(geoDistance(longitude_1, latitude_1, longitude_2, latitude_2)) / 1000) FROM opensky;
+```
+
+Result:
+
+```text
+┌─formatReadableQuantity(divide(sum(geoDistance(longitude_1, latitude_1, longitude_2, latitude_2)), 1000))─┐
+│ 68.72 billion                                                                                            │
+└──────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+Average flight distance is around 1000 km.
+
+Query:
+
+```sql
+SELECT avg(geoDistance(longitude_1, latitude_1, longitude_2, latitude_2)) FROM opensky;
+```
+
+Result:
+
+```text
+┌─avg(geoDistance(longitude_1, latitude_1, longitude_2, latitude_2))─┐
+│                                                 1041090.6465708319 │
+└────────────────────────────────────────────────────────────────────┘
+```
+
+### Most busy origin airports and the average distance seen {#busy-airports-average-distance}
+
+Query:
+
+```sql
+SELECT
+    origin,
+    count(),
+    round(avg(geoDistance(longitude_1, latitude_1, longitude_2, latitude_2))) AS distance,
+    bar(distance, 0, 10000000, 100) AS bar
+FROM opensky
+WHERE origin != ''
+GROUP BY origin
+ORDER BY count() DESC
+LIMIT 100;
+```
+
+Result:
+
+```text
+     ┌─origin─┬─count()─┬─distance─┬─bar────────────────────────────────────┐
+  1. │ KORD   │  745007 │  1546108 │ ███████████████▍                       │
+  2. │ KDFW   │  696702 │  1358721 │ █████████████▌                         │
+  3. │ KATL   │  667286 │  1169661 │ ███████████▋                           │
+  4. │ KDEN   │  582709 │  1287742 │ ████████████▊                          │
+  5. │ KLAX   │  581952 │  2628393 │ ██████████████████████████▎            │
+  6. │ KLAS   │  447789 │  1336967 │ █████████████▎                         │
+  7. │ KPHX   │  428558 │  1345635 │ █████████████▍                         │
+  8. │ KSEA   │  412592 │  1757317 │ █████████████████▌                     │
+  9. │ KCLT   │  404612 │   880355 │ ████████▋                              │
+ 10. │ VIDP   │  363074 │  1445052 │ ██████████████▍                        │
+ 11. │ EDDF   │  362643 │  2263960 │ ██████████████████████▋                │
+ 12. │ KSFO   │  361869 │  2445732 │ ████████████████████████▍              │
+ 13. │ KJFK   │  349232 │  2996550 │ █████████████████████████████▊         │
+ 14. │ KMSP   │  346010 │  1287328 │ ████████████▋                          │
+ 15. │ LFPG   │  344748 │  2206203 │ ██████████████████████                 │
+ 16. │ EGLL   │  341370 │  3216593 │ ████████████████████████████████▏      │
+ 17. │ EHAM   │  340272 │  2116425 │ █████████████████████▏                 │
+ 18. │ KEWR   │  337696 │  1826545 │ ██████████████████▎                    │
+ 19. │ KPHL   │  320762 │  1291761 │ ████████████▊                          │
+ 20. │ OMDB   │  308855 │  2855706 │ ████████████████████████████▌          │
+ 21. │ UUEE   │  307098 │  1555122 │ ███████████████▌                       │
+ 22. │ KBOS   │  304416 │  1621675 │ ████████████████▏                      │
+ 23. │ LEMD   │  291787 │  1695097 │ ████████████████▊                      │
+ 24. │ YSSY   │  272979 │  1875298 │ ██████████████████▋                    │
+ 25. │ KMIA   │  265121 │  1923542 │ ███████████████████▏                   │
+ 26. │ ZGSZ   │  263497 │   745086 │ ███████▍                               │
+ 27. │ EDDM   │  256691 │  1361453 │ █████████████▌                         │
+ 28. │ WMKK   │  254264 │  1626688 │ ████████████████▎                      │
+ 29. │ CYYZ   │  251192 │  2175026 │ █████████████████████▋                 │
+ 30. │ KLGA   │  248699 │  1106935 │ ███████████                            │
+ 31. │ VHHH   │  248473 │  3457658 │ ██████████████████████████████████▌    │
+ 32. │ RJTT   │  243477 │  1272744 │ ████████████▋                          │
+ 33. │ KBWI   │  241440 │  1187060 │ ███████████▋                           │
+ 34. │ KIAD   │  239558 │  1683485 │ ████████████████▋                      │
+ 35. │ KIAH   │  234202 │  1538335 │ ███████████████▍                       │
+ 36. │ KFLL   │  223447 │  1464410 │ ██████████████▋                        │
+ 37. │ KDAL   │  212055 │  1082339 │ ██████████▋                            │
+ 38. │ KDCA   │  207883 │  1013359 │ ██████████▏                            │
+ 39. │ LIRF   │  207047 │  1427965 │ ██████████████▎                        │
+ 40. │ PANC   │  206007 │  2525359 │ █████████████████████████▎             │
+ 41. │ LTFJ   │  205415 │   860470 │ ████████▌                              │
+ 42. │ KDTW   │  204020 │  1106716 │ ███████████                            │
+ 43. │ VABB   │  201679 │  1300865 │ █████████████                          │
+ 44. │ OTHH   │  200797 │  3759544 │ █████████████████████████████████████▌ │
+ 45. │ KMDW   │  200796 │  1232551 │ ████████████▎                          │
+ 46. │ KSAN   │  198003 │  1495195 │ ██████████████▊                        │
+ 47. │ KPDX   │  197760 │  1269230 │ ████████████▋                          │
+ 48. │ SBGR   │  197624 │  2041697 │ ████████████████████▍                  │
+ 49. │ VOBL   │  189011 │  1040180 │ ██████████▍                            │
+ 50. │ LEBL   │  188956 │  1283190 │ ████████████▋                          │
+ 51. │ YBBN   │  188011 │  1253405 │ ████████████▌                          │
+ 52. │ LSZH   │  187934 │  1572029 │ ███████████████▋                       │
+ 53. │ YMML   │  187643 │  1870076 │ ██████████████████▋                    │
+ 54. │ RCTP   │  184466 │  2773976 │ ███████████████████████████▋           │
+ 55. │ KSNA   │  180045 │   778484 │ ███████▋                               │
+ 56. │ EGKK   │  176420 │  1694770 │ ████████████████▊                      │
+ 57. │ LOWW   │  176191 │  1274833 │ ████████████▋                          │
+ 58. │ UUDD   │  176099 │  1368226 │ █████████████▋                         │
+ 59. │ RKSI   │  173466 │  3079026 │ ██████████████████████████████▋        │
+ 60. │ EKCH   │  172128 │  1229895 │ ████████████▎                          │
+ 61. │ KOAK   │  171119 │  1114447 │ ███████████▏                           │
+ 62. │ RPLL   │  170122 │  1440735 │ ██████████████▍                        │
+ 63. │ KRDU   │  167001 │   830521 │ ████████▎                              │
+ 64. │ KAUS   │  164524 │  1256198 │ ████████████▌                          │
+ 65. │ KBNA   │  163242 │  1022726 │ ██████████▏                            │
+ 66. │ KSDF   │  162655 │  1380867 │ █████████████▋                         │
+ 67. │ ENGM   │  160732 │   910108 │ █████████                              │
+ 68. │ LIMC   │  160696 │  1564620 │ ███████████████▋                       │
+ 69. │ KSJC   │  159278 │  1081125 │ ██████████▋                            │
+ 70. │ KSTL   │  157984 │  1026699 │ ██████████▎                            │
+ 71. │ UUWW   │  156811 │  1261155 │ ████████████▌                          │
+ 72. │ KIND   │  153929 │   987944 │ █████████▊                             │
+ 73. │ ESSA   │  153390 │  1203439 │ ████████████                           │
+ 74. │ KMCO   │  153351 │  1508657 │ ███████████████                        │
+ 75. │ KDVT   │  152895 │    74048 │ ▋                                      │
+ 76. │ VTBS   │  152645 │  2255591 │ ██████████████████████▌                │
+ 77. │ CYVR   │  149574 │  2027413 │ ████████████████████▎                  │
+ 78. │ EIDW   │  148723 │  1503985 │ ███████████████                        │
+ 79. │ LFPO   │  143277 │  1152964 │ ███████████▌                           │
+ 80. │ EGSS   │  140830 │  1348183 │ █████████████▍                         │
+ 81. │ KAPA   │  140776 │   420441 │ ████▏                                  │
+ 82. │ KHOU   │  138985 │  1068806 │ ██████████▋                            │
+ 83. │ KTPA   │  138033 │  1338223 │ █████████████▍                         │
+ 84. │ KFFZ   │  137333 │    55397 │ ▌                                      │
+ 85. │ NZAA   │  136092 │  1581264 │ ███████████████▋                       │
+ 86. │ YPPH   │  133916 │  1271550 │ ████████████▋                          │
+ 87. │ RJBB   │  133522 │  1805623 │ ██████████████████                     │
+ 88. │ EDDL   │  133018 │  1265919 │ ████████████▋                          │
+ 89. │ ULLI   │  130501 │  1197108 │ ███████████▊                           │
+ 90. │ KIWA   │  127195 │   250876 │ ██▌                                    │
+ 91. │ KTEB   │  126969 │  1189414 │ ███████████▊                           │
+ 92. │ VOMM   │  125616 │  1127757 │ ███████████▎                           │
+ 93. │ LSGG   │  123998 │  1049101 │ ██████████▍                            │
+ 94. │ LPPT   │  122733 │  1779187 │ █████████████████▋                     │
+ 95. │ WSSS   │  120493 │  3264122 │ ████████████████████████████████▋      │
+ 96. │ EBBR   │  118539 │  1579939 │ ███████████████▋                       │
+ 97. │ VTBD   │  118107 │   661627 │ ██████▌                                │
+ 98. │ KVNY   │  116326 │   692960 │ ██████▊                                │
+ 99. │ EDDT   │  115122 │   941740 │ █████████▍                             │
+100. │ EFHK   │  114860 │  1629143 │ ████████████████▎                      │
+     └────────┴─────────┴──────────┴────────────────────────────────────────┘
+```
+
+### Number of flights from three major Moscow airports, weekly {#flights-from-moscow}
+
+Query:
+
+```sql
+SELECT
+    toMonday(day) AS k,
+    count() AS c,
+    bar(c, 0, 10000, 100) AS bar
+FROM opensky
+WHERE origin IN ('UUEE', 'UUDD', 'UUWW')
+GROUP BY k
+ORDER BY k ASC;
+```
+
+Result:
+
+```text
+     ┌──────────k─┬────c─┬─bar──────────────────────────────────────────────────────────────────────────┐
+  1. │ 2018-12-31 │ 5248 │ ████████████████████████████████████████████████████▍                        │
+  2. │ 2019-01-07 │ 6302 │ ███████████████████████████████████████████████████████████████              │
+  3. │ 2019-01-14 │ 5701 │ █████████████████████████████████████████████████████████                    │
+  4. │ 2019-01-21 │ 5638 │ ████████████████████████████████████████████████████████▍                    │
+  5. │ 2019-01-28 │ 5731 │ █████████████████████████████████████████████████████████▎                   │
+  6. │ 2019-02-04 │ 5683 │ ████████████████████████████████████████████████████████▋                    │
+  7. │ 2019-02-11 │ 5759 │ █████████████████████████████████████████████████████████▌                   │
+  8. │ 2019-02-18 │ 5736 │ █████████████████████████████████████████████████████████▎                   │
+  9. │ 2019-02-25 │ 5873 │ ██████████████████████████████████████████████████████████▋                  │
+ 10. │ 2019-03-04 │ 5965 │ ███████████████████████████████████████████████████████████▋                 │
+ 11. │ 2019-03-11 │ 5900 │ ███████████████████████████████████████████████████████████                  │
+ 12. │ 2019-03-18 │ 5823 │ ██████████████████████████████████████████████████████████▏                  │
+ 13. │ 2019-03-25 │ 5899 │ ██████████████████████████████████████████████████████████▊                  │
+ 14. │ 2019-04-01 │ 6043 │ ████████████████████████████████████████████████████████████▍                │
+ 15. │ 2019-04-08 │ 6098 │ ████████████████████████████████████████████████████████████▊                │
+ 16. │ 2019-04-15 │ 6196 │ █████████████████████████████████████████████████████████████▊               │
+ 17. │ 2019-04-22 │ 6486 │ ████████████████████████████████████████████████████████████████▋            │
+ 18. │ 2019-04-29 │ 6682 │ ██████████████████████████████████████████████████████████████████▋          │
+ 19. │ 2019-05-06 │ 6739 │ ███████████████████████████████████████████████████████████████████▍         │
+ 20. │ 2019-05-13 │ 6600 │ ██████████████████████████████████████████████████████████████████           │
+ 21. │ 2019-05-20 │ 6575 │ █████████████████████████████████████████████████████████████████▋           │
+ 22. │ 2019-05-27 │ 6786 │ ███████████████████████████████████████████████████████████████████▋         │
+ 23. │ 2019-06-03 │ 6872 │ ████████████████████████████████████████████████████████████████████▋        │
+ 24. │ 2019-06-10 │ 7045 │ ██████████████████████████████████████████████████████████████████████▍      │
+ 25. │ 2019-06-17 │ 7045 │ ██████████████████████████████████████████████████████████████████████▍      │
+ 26. │ 2019-06-24 │ 6852 │ ████████████████████████████████████████████████████████████████████▌        │
+ 27. │ 2019-07-01 │ 7248 │ ████████████████████████████████████████████████████████████████████████▍    │
+ 28. │ 2019-07-08 │ 7284 │ ████████████████████████████████████████████████████████████████████████▋    │
+ 29. │ 2019-07-15 │ 7142 │ ███████████████████████████████████████████████████████████████████████▍     │
+ 30. │ 2019-07-22 │ 7108 │ ███████████████████████████████████████████████████████████████████████      │
+ 31. │ 2019-07-29 │ 7251 │ ████████████████████████████████████████████████████████████████████████▌    │
+ 32. │ 2019-08-05 │ 7403 │ ██████████████████████████████████████████████████████████████████████████   │
+ 33. │ 2019-08-12 │ 7457 │ ██████████████████████████████████████████████████████████████████████████▌  │
+ 34. │ 2019-08-19 │ 7502 │ ███████████████████████████████████████████████████████████████████████████  │
+ 35. │ 2019-08-26 │ 7540 │ ███████████████████████████████████████████████████████████████████████████▍ │
+ 36. │ 2019-09-02 │ 7237 │ ████████████████████████████████████████████████████████████████████████▎    │
+ 37. │ 2019-09-09 │ 7328 │ █████████████████████████████████████████████████████████████████████████▎   │
+ 38. │ 2019-09-16 │ 5566 │ ███████████████████████████████████████████████████████▋                     │
+ 39. │ 2019-09-23 │ 7049 │ ██████████████████████████████████████████████████████████████████████▍      │
+ 40. │ 2019-09-30 │ 6880 │ ████████████████████████████████████████████████████████████████████▋        │
+ 41. │ 2019-10-07 │ 6518 │ █████████████████████████████████████████████████████████████████▏           │
+ 42. │ 2019-10-14 │ 6688 │ ██████████████████████████████████████████████████████████████████▊          │
+ 43. │ 2019-10-21 │ 6667 │ ██████████████████████████████████████████████████████████████████▋          │
+ 44. │ 2019-10-28 │ 6303 │ ███████████████████████████████████████████████████████████████              │
+ 45. │ 2019-11-04 │ 6298 │ ██████████████████████████████████████████████████████████████▊              │
+ 46. │ 2019-11-11 │ 6137 │ █████████████████████████████████████████████████████████████▎               │
+ 47. │ 2019-11-18 │ 6051 │ ████████████████████████████████████████████████████████████▌                │
+ 48. │ 2019-11-25 │ 5820 │ ██████████████████████████████████████████████████████████▏                  │
+ 49. │ 2019-12-02 │ 5942 │ ███████████████████████████████████████████████████████████▍                 │
+ 50. │ 2019-12-09 │ 4891 │ ████████████████████████████████████████████████▊                            │
+ 51. │ 2019-12-16 │ 5682 │ ████████████████████████████████████████████████████████▋                    │
+ 52. │ 2019-12-23 │ 6111 │ █████████████████████████████████████████████████████████████                │
+ 53. │ 2019-12-30 │ 5870 │ ██████████████████████████████████████████████████████████▋                  │
+ 54. │ 2020-01-06 │ 5953 │ ███████████████████████████████████████████████████████████▌                 │
+ 55. │ 2020-01-13 │ 5698 │ ████████████████████████████████████████████████████████▊                    │
+ 56. │ 2020-01-20 │ 5339 │ █████████████████████████████████████████████████████▍                       │
+ 57. │ 2020-01-27 │ 5566 │ ███████████████████████████████████████████████████████▋                     │
+ 58. │ 2020-02-03 │ 5801 │ ██████████████████████████████████████████████████████████                   │
+ 59. │ 2020-02-10 │ 5692 │ ████████████████████████████████████████████████████████▊                    │
+ 60. │ 2020-02-17 │ 5912 │ ███████████████████████████████████████████████████████████                  │
+ 61. │ 2020-02-24 │ 6031 │ ████████████████████████████████████████████████████████████▎                │
+ 62. │ 2020-03-02 │ 6105 │ █████████████████████████████████████████████████████████████                │
+ 63. │ 2020-03-09 │ 5823 │ ██████████████████████████████████████████████████████████▏                  │
+ 64. │ 2020-03-16 │ 4659 │ ██████████████████████████████████████████████▌                              │
+ 65. │ 2020-03-23 │ 3720 │ █████████████████████████████████████▏                                       │
+ 66. │ 2020-03-30 │ 1720 │ █████████████████▏                                                           │
+ 67. │ 2020-04-06 │  849 │ ████████▍                                                                    │
+ 68. │ 2020-04-13 │  710 │ ███████                                                                      │
+ 69. │ 2020-04-20 │  725 │ ███████▏                                                                     │
+ 70. │ 2020-04-27 │  920 │ █████████▏                                                                   │
+ 71. │ 2020-05-04 │  859 │ ████████▌                                                                    │
+ 72. │ 2020-05-11 │ 1047 │ ██████████▍                                                                  │
+ 73. │ 2020-05-18 │ 1135 │ ███████████▎                                                                 │
+ 74. │ 2020-05-25 │ 1266 │ ████████████▋                                                                │
+ 75. │ 2020-06-01 │ 1793 │ █████████████████▊                                                           │
+ 76. │ 2020-06-08 │ 1979 │ ███████████████████▋                                                         │
+ 77. │ 2020-06-15 │ 2297 │ ██████████████████████▊                                                      │
+ 78. │ 2020-06-22 │ 2788 │ ███████████████████████████▊                                                 │
+ 79. │ 2020-06-29 │ 3389 │ █████████████████████████████████▊                                           │
+ 80. │ 2020-07-06 │ 3545 │ ███████████████████████████████████▍                                         │
+ 81. │ 2020-07-13 │ 3569 │ ███████████████████████████████████▋                                         │
+ 82. │ 2020-07-20 │ 3784 │ █████████████████████████████████████▋                                       │
+ 83. │ 2020-07-27 │ 3960 │ ███████████████████████████████████████▌                                     │
+ 84. │ 2020-08-03 │ 4323 │ ███████████████████████████████████████████▏                                 │
+ 85. │ 2020-08-10 │ 4581 │ █████████████████████████████████████████████▋                               │
+ 86. │ 2020-08-17 │ 4791 │ ███████████████████████████████████████████████▊                             │
+ 87. │ 2020-08-24 │ 4928 │ █████████████████████████████████████████████████▎                           │
+ 88. │ 2020-08-31 │ 4687 │ ██████████████████████████████████████████████▋                              │
+ 89. │ 2020-09-07 │ 4643 │ ██████████████████████████████████████████████▍                              │
+ 90. │ 2020-09-14 │ 4594 │ █████████████████████████████████████████████▊                               │
+ 91. │ 2020-09-21 │ 4478 │ ████████████████████████████████████████████▋                                │
+ 92. │ 2020-09-28 │ 4382 │ ███████████████████████████████████████████▋                                 │
+ 93. │ 2020-10-05 │ 4261 │ ██████████████████████████████████████████▌                                  │
+ 94. │ 2020-10-12 │ 4243 │ ██████████████████████████████████████████▍                                  │
+ 95. │ 2020-10-19 │ 3941 │ ███████████████████████████████████████▍                                     │
+ 96. │ 2020-10-26 │ 3616 │ ████████████████████████████████████▏                                        │
+ 97. │ 2020-11-02 │ 3586 │ ███████████████████████████████████▋                                         │
+ 98. │ 2020-11-09 │ 3403 │ ██████████████████████████████████                                           │
+ 99. │ 2020-11-16 │ 3336 │ █████████████████████████████████▎                                           │
+100. │ 2020-11-23 │ 3230 │ ████████████████████████████████▎                                            │
+101. │ 2020-11-30 │ 3183 │ ███████████████████████████████▋                                             │
+102. │ 2020-12-07 │ 3285 │ ████████████████████████████████▋                                            │
+103. │ 2020-12-14 │ 3367 │ █████████████████████████████████▋                                           │
+104. │ 2020-12-21 │ 3748 │ █████████████████████████████████████▍                                       │
+105. │ 2020-12-28 │ 3986 │ ███████████████████████████████████████▋                                     │
+106. │ 2021-01-04 │ 3906 │ ███████████████████████████████████████                                      │
+107. │ 2021-01-11 │ 3425 │ ██████████████████████████████████▎                                          │
+108. │ 2021-01-18 │ 3144 │ ███████████████████████████████▍                                             │
+109. │ 2021-01-25 │ 3115 │ ███████████████████████████████▏                                             │
+110. │ 2021-02-01 │ 3285 │ ████████████████████████████████▋                                            │
+111. │ 2021-02-08 │ 3321 │ █████████████████████████████████▏                                           │
+112. │ 2021-02-15 │ 3475 │ ██████████████████████████████████▋                                          │
+113. │ 2021-02-22 │ 3549 │ ███████████████████████████████████▍                                         │
+114. │ 2021-03-01 │ 3755 │ █████████████████████████████████████▌                                       │
+115. │ 2021-03-08 │ 3080 │ ██████████████████████████████▋                                              │
+116. │ 2021-03-15 │ 3789 │ █████████████████████████████████████▊                                       │
+117. │ 2021-03-22 │ 3804 │ ██████████████████████████████████████                                       │
+118. │ 2021-03-29 │ 4238 │ ██████████████████████████████████████████▍                                  │
+119. │ 2021-04-05 │ 4307 │ ███████████████████████████████████████████                                  │
+120. │ 2021-04-12 │ 4225 │ ██████████████████████████████████████████▎                                  │
+121. │ 2021-04-19 │ 4391 │ ███████████████████████████████████████████▊                                 │
+122. │ 2021-04-26 │ 4868 │ ████████████████████████████████████████████████▋                            │
+123. │ 2021-05-03 │ 4977 │ █████████████████████████████████████████████████▋                           │
+124. │ 2021-05-10 │ 5164 │ ███████████████████████████████████████████████████▋                         │
+125. │ 2021-05-17 │ 4986 │ █████████████████████████████████████████████████▋                           │
+126. │ 2021-05-24 │ 5024 │ ██████████████████████████████████████████████████▏                          │
+127. │ 2021-05-31 │ 4824 │ ████████████████████████████████████████████████▏                            │
+128. │ 2021-06-07 │ 5652 │ ████████████████████████████████████████████████████████▌                    │
+129. │ 2021-06-14 │ 5613 │ ████████████████████████████████████████████████████████▏                    │
+130. │ 2021-06-21 │ 6061 │ ████████████████████████████████████████████████████████████▌                │
+131. │ 2021-06-28 │ 2554 │ █████████████████████████▌                                                   │
+     └────────────┴──────┴──────────────────────────────────────────────────────────────────────────────┘
+```
+
+### Online Playground {#playground}
+
+You can test other queries to this data set using the interactive resource [Online Playground](https://gh-api.clickhouse.com/play?user=play). For example, [like this](https://gh-api.clickhouse.com/play?user=play#U0VMRUNUCiAgICBvcmlnaW4sCiAgICBjb3VudCgpLAogICAgcm91bmQoYXZnKGdlb0Rpc3RhbmNlKGxvbmdpdHVkZV8xLCBsYXRpdHVkZV8xLCBsb25naXR1ZGVfMiwgbGF0aXR1ZGVfMikpKSBBUyBkaXN0YW5jZSwKICAgIGJhcihkaXN0YW5jZSwgMCwgMTAwMDAwMDAsIDEwMCkgQVMgYmFyCkZST00gb3BlbnNreQpXSEVSRSBvcmlnaW4gIT0gJycKR1JPVVAgQlkgb3JpZ2luCk9SREVSIEJZIGNvdW50KCkgREVTQwpMSU1JVCAxMDA=). However, please note that you cannot create temporary tables here.
diff --git a/docs/en/reference/getting-started/example-datasets/recipes.md b/docs/en/reference/getting-started/example-datasets/recipes.md
new file mode 100644
index 00000000000..1ae2493befb
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/recipes.md
@@ -0,0 +1,339 @@
+---
+sidebar_label: Recipes Dataset
+---
+
+# Recipes Dataset
+
+RecipeNLG dataset is available for download [here](https://recipenlg.cs.put.poznan.pl/dataset). It contains 2.2 million recipes. The size is slightly less than 1 GB.
+
+## Download and Unpack the Dataset
+
+1. Go to the download page [https://recipenlg.cs.put.poznan.pl/dataset](https://recipenlg.cs.put.poznan.pl/dataset).
+1. Accept Terms and Conditions and download zip file.
+1. Unpack the zip file with `unzip`. You will get the `full_dataset.csv` file.
+
+## Create a Table
+
+Run clickhouse-client and execute the following CREATE query:
+
+``` sql
+CREATE TABLE recipes
+(
+    title String,
+    ingredients Array(String),
+    directions Array(String),
+    link String,
+    source LowCardinality(String),
+    NER Array(String)
+) ENGINE = MergeTree ORDER BY title;
+```
+
+## Insert the Data
+
+Run the following command:
+
+``` bash
+clickhouse-client --query "
+    INSERT INTO recipes
+    SELECT
+        title,
+        JSONExtract(ingredients, 'Array(String)'),
+        JSONExtract(directions, 'Array(String)'),
+        link,
+        source,
+        JSONExtract(NER, 'Array(String)')
+    FROM input('num UInt32, title String, ingredients String, directions String, link String, source LowCardinality(String), NER String')
+    FORMAT CSVWithNames
+" --input_format_with_names_use_header 0 --format_csv_allow_single_quote 0 --input_format_allow_errors_num 10 < full_dataset.csv
+```
+
+This is a showcase how to parse custom CSV, as it requires multiple tunes.
+
+Explanation:
+-   The dataset is in CSV format, but it requires some preprocessing on insertion; we use table function [input](../sql-reference/table-functions/input.md) to perform preprocessing;
+-   The structure of CSV file is specified in the argument of the table function `input`;
+-   The field `num` (row number) is unneeded - we parse it from file and ignore;
+-   We use `FORMAT CSVWithNames` but the header in CSV will be ignored (by command line parameter `--input_format_with_names_use_header 0`), because the header does not contain the name for the first field;
+-   File is using only double quotes to enclose CSV strings; some strings are not enclosed in double quotes, and single quote must not be parsed as the string enclosing - that's why we also add the `--format_csv_allow_single_quote 0` parameter;
+-   Some strings from CSV cannot parse, because they contain `\M/` sequence at the beginning of the value; the only value starting with backslash in CSV can be `\N` that is parsed as SQL NULL. We add `--input_format_allow_errors_num 10` parameter and up to ten malformed records can be skipped;
+-   There are arrays for ingredients, directions and NER fields; these arrays are represented in unusual form: they are serialized into string as JSON and then placed in CSV - we parse them as String and then use [JSONExtract](../sql-reference/functions/json-functions.md) function to transform it to Array.
+
+## Validate the Inserted Data
+
+By checking the row count:
+
+Query:
+
+``` sql
+SELECT count() FROM recipes;
+```
+
+Result:
+
+``` text
+┌─count()─┐
+│ 2231141 │
+└─────────┘
+```
+
+## Example Queries
+
+### Top Components by the Number of Recipes:
+
+In this example we learn how to use [arrayJoin](../sql-reference/functions/array-join/) function to expand an array into a set of rows.
+
+Query:
+
+``` sql
+SELECT
+    arrayJoin(NER) AS k,
+    count() AS c
+FROM recipes
+GROUP BY k
+ORDER BY c DESC
+LIMIT 50
+```
+
+Result:
+
+``` text
+┌─k────────────────────┬──────c─┐
+│ salt                 │ 890741 │
+│ sugar                │ 620027 │
+│ butter               │ 493823 │
+│ flour                │ 466110 │
+│ eggs                 │ 401276 │
+│ onion                │ 372469 │
+│ garlic               │ 358364 │
+│ milk                 │ 346769 │
+│ water                │ 326092 │
+│ vanilla              │ 270381 │
+│ olive oil            │ 197877 │
+│ pepper               │ 179305 │
+│ brown sugar          │ 174447 │
+│ tomatoes             │ 163933 │
+│ egg                  │ 160507 │
+│ baking powder        │ 148277 │
+│ lemon juice          │ 146414 │
+│ Salt                 │ 122557 │
+│ cinnamon             │ 117927 │
+│ sour cream           │ 116682 │
+│ cream cheese         │ 114423 │
+│ margarine            │ 112742 │
+│ celery               │ 112676 │
+│ baking soda          │ 110690 │
+│ parsley              │ 102151 │
+│ chicken              │ 101505 │
+│ onions               │  98903 │
+│ vegetable oil        │  91395 │
+│ oil                  │  85600 │
+│ mayonnaise           │  84822 │
+│ pecans               │  79741 │
+│ nuts                 │  78471 │
+│ potatoes             │  75820 │
+│ carrots              │  75458 │
+│ pineapple            │  74345 │
+│ soy sauce            │  70355 │
+│ black pepper         │  69064 │
+│ thyme                │  68429 │
+│ mustard              │  65948 │
+│ chicken broth        │  65112 │
+│ bacon                │  64956 │
+│ honey                │  64626 │
+│ oregano              │  64077 │
+│ ground beef          │  64068 │
+│ unsalted butter      │  63848 │
+│ mushrooms            │  61465 │
+│ Worcestershire sauce │  59328 │
+│ cornstarch           │  58476 │
+│ green pepper         │  58388 │
+│ Cheddar cheese       │  58354 │
+└──────────────────────┴────────┘
+
+50 rows in set. Elapsed: 0.112 sec. Processed 2.23 million rows, 361.57 MB (19.99 million rows/s., 3.24 GB/s.)
+```
+
+### The Most Complex Recipes with Strawberry
+
+``` sql
+SELECT
+    title,
+    length(NER),
+    length(directions)
+FROM recipes
+WHERE has(NER, 'strawberry')
+ORDER BY length(directions) DESC
+LIMIT 10
+```
+
+Result:
+
+``` text
+┌─title────────────────────────────────────────────────────────────┬─length(NER)─┬─length(directions)─┐
+│ Chocolate-Strawberry-Orange Wedding Cake                         │          24 │                126 │
+│ Strawberry Cream Cheese Crumble Tart                             │          19 │                 47 │
+│ Charlotte-Style Ice Cream                                        │          11 │                 45 │
+│ Sinfully Good a Million Layers Chocolate Layer Cake, With Strawb │          31 │                 45 │
+│ Sweetened Berries With Elderflower Sherbet                       │          24 │                 44 │
+│ Chocolate-Strawberry Mousse Cake                                 │          15 │                 42 │
+│ Rhubarb Charlotte with Strawberries and Rum                      │          20 │                 42 │
+│ Chef Joey's Strawberry Vanilla Tart                              │           7 │                 37 │
+│ Old-Fashioned Ice Cream Sundae Cake                              │          17 │                 37 │
+│ Watermelon Cake                                                  │          16 │                 36 │
+└──────────────────────────────────────────────────────────────────┴─────────────┴────────────────────┘
+
+10 rows in set. Elapsed: 0.215 sec. Processed 2.23 million rows, 1.48 GB (10.35 million rows/s., 6.86 GB/s.)
+```
+
+In this example, we involve [has](../sql-reference/functions/array-functions/#hasarr-elem) function to filter by array elements and sort by the number of directions.
+
+There is a wedding cake that requires the whole 126 steps to produce! Show that directions:
+
+Query:
+
+``` sql
+SELECT arrayJoin(directions)
+FROM recipes
+WHERE title = 'Chocolate-Strawberry-Orange Wedding Cake'
+```
+
+Result:
+
+``` text
+┌─arrayJoin(directions)───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Position 1 rack in center and 1 rack in bottom third of oven and preheat to 350F.                                                                                           │
+│ Butter one 5-inch-diameter cake pan with 2-inch-high sides, one 8-inch-diameter cake pan with 2-inch-high sides and one 12-inch-diameter cake pan with 2-inch-high sides.   │
+│ Dust pans with flour; line bottoms with parchment.                                                                                                                          │
+│ Combine 1/3 cup orange juice and 2 ounces unsweetened chocolate in heavy small saucepan.                                                                                    │
+│ Stir mixture over medium-low heat until chocolate melts.                                                                                                                    │
+│ Remove from heat.                                                                                                                                                           │
+│ Gradually mix in 1 2/3 cups orange juice.                                                                                                                                   │
+│ Sift 3 cups flour, 2/3 cup cocoa, 2 teaspoons baking soda, 1 teaspoon salt and 1/2 teaspoon baking powder into medium bowl.                                                 │
+│ using electric mixer, beat 1 cup (2 sticks) butter and 3 cups sugar in large bowl until blended (mixture will look grainy).                                                 │
+│ Add 4 eggs, 1 at a time, beating to blend after each.                                                                                                                       │
+│ Beat in 1 tablespoon orange peel and 1 tablespoon vanilla extract.                                                                                                          │
+│ Add dry ingredients alternately with orange juice mixture in 3 additions each, beating well after each addition.                                                            │
+│ Mix in 1 cup chocolate chips.                                                                                                                                               │
+│ Transfer 1 cup plus 2 tablespoons batter to prepared 5-inch pan, 3 cups batter to prepared 8-inch pan and remaining batter (about 6 cups) to 12-inch pan.                   │
+│ Place 5-inch and 8-inch pans on center rack of oven.                                                                                                                        │
+│ Place 12-inch pan on lower rack of oven.                                                                                                                                    │
+│ Bake cakes until tester inserted into center comes out clean, about 35 minutes.                                                                                             │
+│ Transfer cakes in pans to racks and cool completely.                                                                                                                        │
+│ Mark 4-inch diameter circle on one 6-inch-diameter cardboard cake round.                                                                                                    │
+│ Cut out marked circle.                                                                                                                                                      │
+│ Mark 7-inch-diameter circle on one 8-inch-diameter cardboard cake round.                                                                                                    │
+│ Cut out marked circle.                                                                                                                                                      │
+│ Mark 11-inch-diameter circle on one 12-inch-diameter cardboard cake round.                                                                                                  │
+│ Cut out marked circle.                                                                                                                                                      │
+│ Cut around sides of 5-inch-cake to loosen.                                                                                                                                  │
+│ Place 4-inch cardboard over pan.                                                                                                                                            │
+│ Hold cardboard and pan together; turn cake out onto cardboard.                                                                                                              │
+│ Peel off parchment.Wrap cakes on its cardboard in foil.                                                                                                                     │
+│ Repeat turning out, peeling off parchment and wrapping cakes in foil, using 7-inch cardboard for 8-inch cake and 11-inch cardboard for 12-inch cake.                        │
+│ Using remaining ingredients, make 1 more batch of cake batter and bake 3 more cake layers as described above.                                                               │
+│ Cool cakes in pans.                                                                                                                                                         │
+│ Cover cakes in pans tightly with foil.                                                                                                                                      │
+│ (Can be prepared ahead.                                                                                                                                                     │
+│ Let stand at room temperature up to 1 day or double-wrap all cake layers and freeze up to 1 week.                                                                           │
+│ Bring cake layers to room temperature before using.)                                                                                                                        │
+│ Place first 12-inch cake on its cardboard on work surface.                                                                                                                  │
+│ Spread 2 3/4 cups ganache over top of cake and all the way to edge.                                                                                                         │
+│ Spread 2/3 cup jam over ganache, leaving 1/2-inch chocolate border at edge.                                                                                                 │
+│ Drop 1 3/4 cups white chocolate frosting by spoonfuls over jam.                                                                                                             │
+│ Gently spread frosting over jam, leaving 1/2-inch chocolate border at edge.                                                                                                 │
+│ Rub some cocoa powder over second 12-inch cardboard.                                                                                                                        │
+│ Cut around sides of second 12-inch cake to loosen.                                                                                                                          │
+│ Place cardboard, cocoa side down, over pan.                                                                                                                                 │
+│ Turn cake out onto cardboard.                                                                                                                                               │
+│ Peel off parchment.                                                                                                                                                         │
+│ Carefully slide cake off cardboard and onto filling on first 12-inch cake.                                                                                                  │
+│ Refrigerate.                                                                                                                                                                │
+│ Place first 8-inch cake on its cardboard on work surface.                                                                                                                   │
+│ Spread 1 cup ganache over top all the way to edge.                                                                                                                          │
+│ Spread 1/4 cup jam over, leaving 1/2-inch chocolate border at edge.                                                                                                         │
+│ Drop 1 cup white chocolate frosting by spoonfuls over jam.                                                                                                                  │
+│ Gently spread frosting over jam, leaving 1/2-inch chocolate border at edge.                                                                                                 │
+│ Rub some cocoa over second 8-inch cardboard.                                                                                                                                │
+│ Cut around sides of second 8-inch cake to loosen.                                                                                                                           │
+│ Place cardboard, cocoa side down, over pan.                                                                                                                                 │
+│ Turn cake out onto cardboard.                                                                                                                                               │
+│ Peel off parchment.                                                                                                                                                         │
+│ Slide cake off cardboard and onto filling on first 8-inch cake.                                                                                                             │
+│ Refrigerate.                                                                                                                                                                │
+│ Place first 5-inch cake on its cardboard on work surface.                                                                                                                   │
+│ Spread 1/2 cup ganache over top of cake and all the way to edge.                                                                                                            │
+│ Spread 2 tablespoons jam over, leaving 1/2-inch chocolate border at edge.                                                                                                   │
+│ Drop 1/3 cup white chocolate frosting by spoonfuls over jam.                                                                                                                │
+│ Gently spread frosting over jam, leaving 1/2-inch chocolate border at edge.                                                                                                 │
+│ Rub cocoa over second 6-inch cardboard.                                                                                                                                     │
+│ Cut around sides of second 5-inch cake to loosen.                                                                                                                           │
+│ Place cardboard, cocoa side down, over pan.                                                                                                                                 │
+│ Turn cake out onto cardboard.                                                                                                                                               │
+│ Peel off parchment.                                                                                                                                                         │
+│ Slide cake off cardboard and onto filling on first 5-inch cake.                                                                                                             │
+│ Chill all cakes 1 hour to set filling.                                                                                                                                      │
+│ Place 12-inch tiered cake on its cardboard on revolving cake stand.                                                                                                         │
+│ Spread 2 2/3 cups frosting over top and sides of cake as a first coat.                                                                                                      │
+│ Refrigerate cake.                                                                                                                                                           │
+│ Place 8-inch tiered cake on its cardboard on cake stand.                                                                                                                    │
+│ Spread 1 1/4 cups frosting over top and sides of cake as a first coat.                                                                                                      │
+│ Refrigerate cake.                                                                                                                                                           │
+│ Place 5-inch tiered cake on its cardboard on cake stand.                                                                                                                    │
+│ Spread 3/4 cup frosting over top and sides of cake as a first coat.                                                                                                         │
+│ Refrigerate all cakes until first coats of frosting set, about 1 hour.                                                                                                      │
+│ (Cakes can be made to this point up to 1 day ahead; cover and keep refrigerate.)                                                                                            │
+│ Prepare second batch of frosting, using remaining frosting ingredients and following directions for first batch.                                                            │
+│ Spoon 2 cups frosting into pastry bag fitted with small star tip.                                                                                                           │
+│ Place 12-inch cake on its cardboard on large flat platter.                                                                                                                  │
+│ Place platter on cake stand.                                                                                                                                                │
+│ Using icing spatula, spread 2 1/2 cups frosting over top and sides of cake; smooth top.                                                                                     │
+│ Using filled pastry bag, pipe decorative border around top edge of cake.                                                                                                    │
+│ Refrigerate cake on platter.                                                                                                                                                │
+│ Place 8-inch cake on its cardboard on cake stand.                                                                                                                           │
+│ Using icing spatula, spread 1 1/2 cups frosting over top and sides of cake; smooth top.                                                                                     │
+│ Using pastry bag, pipe decorative border around top edge of cake.                                                                                                           │
+│ Refrigerate cake on its cardboard.                                                                                                                                          │
+│ Place 5-inch cake on its cardboard on cake stand.                                                                                                                           │
+│ Using icing spatula, spread 3/4 cup frosting over top and sides of cake; smooth top.                                                                                        │
+│ Using pastry bag, pipe decorative border around top edge of cake, spooning more frosting into bag if necessary.                                                             │
+│ Refrigerate cake on its cardboard.                                                                                                                                          │
+│ Keep all cakes refrigerated until frosting sets, about 2 hours.                                                                                                             │
+│ (Can be prepared 2 days ahead.                                                                                                                                              │
+│ Cover loosely; keep refrigerated.)                                                                                                                                          │
+│ Place 12-inch cake on platter on work surface.                                                                                                                              │
+│ Press 1 wooden dowel straight down into and completely through center of cake.                                                                                              │
+│ Mark dowel 1/4 inch above top of frosting.                                                                                                                                  │
+│ Remove dowel and cut with serrated knife at marked point.                                                                                                                   │
+│ Cut 4 more dowels to same length.                                                                                                                                           │
+│ Press 1 cut dowel back into center of cake.                                                                                                                                 │
+│ Press remaining 4 cut dowels into cake, positioning 3 1/2 inches inward from cake edges and spacing evenly.                                                                 │
+│ Place 8-inch cake on its cardboard on work surface.                                                                                                                         │
+│ Press 1 dowel straight down into and completely through center of cake.                                                                                                     │
+│ Mark dowel 1/4 inch above top of frosting.                                                                                                                                  │
+│ Remove dowel and cut with serrated knife at marked point.                                                                                                                   │
+│ Cut 3 more dowels to same length.                                                                                                                                           │
+│ Press 1 cut dowel back into center of cake.                                                                                                                                 │
+│ Press remaining 3 cut dowels into cake, positioning 2 1/2 inches inward from edges and spacing evenly.                                                                      │
+│ Using large metal spatula as aid, place 8-inch cake on its cardboard atop dowels in 12-inch cake, centering carefully.                                                      │
+│ Gently place 5-inch cake on its cardboard atop dowels in 8-inch cake, centering carefully.                                                                                  │
+│ Using citrus stripper, cut long strips of orange peel from oranges.                                                                                                         │
+│ Cut strips into long segments.                                                                                                                                              │
+│ To make orange peel coils, wrap peel segment around handle of wooden spoon; gently slide peel off handle so that peel keeps coiled shape.                                   │
+│ Garnish cake with orange peel coils, ivy or mint sprigs, and some berries.                                                                                                  │
+│ (Assembled cake can be made up to 8 hours ahead.                                                                                                                            │
+│ Let stand at cool room temperature.)                                                                                                                                        │
+│ Remove top and middle cake tiers.                                                                                                                                           │
+│ Remove dowels from cakes.                                                                                                                                                   │
+│ Cut top and middle cakes into slices.                                                                                                                                       │
+│ To cut 12-inch cake: Starting 3 inches inward from edge and inserting knife straight down, cut through from top to bottom to make 6-inch-diameter circle in center of cake. │
+│ Cut outer portion of cake into slices; cut inner portion into slices and serve with strawberries.                                                                           │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+
+126 rows in set. Elapsed: 0.011 sec. Processed 8.19 thousand rows, 5.34 MB (737.75 thousand rows/s., 480.59 MB/s.)
+```
+
+### Online Playground
+
+The dataset is also available in the [Online Playground](https://gh-api.clickhouse.com/play?user=play#U0VMRUNUCiAgICBhcnJheUpvaW4oTkVSKSBBUyBrLAogICAgY291bnQoKSBBUyBjCkZST00gcmVjaXBlcwpHUk9VUCBCWSBrCk9SREVSIEJZIGMgREVTQwpMSU1JVCA1MA==).
+
+[Original article](https://clickhouse.com/docs/en/getting-started/example-datasets/recipes/) <!--hide-->
diff --git a/docs/en/reference/getting-started/example-datasets/star-schema.md b/docs/en/reference/getting-started/example-datasets/star-schema.md
new file mode 100644
index 00000000000..35ff492c360
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/star-schema.md
@@ -0,0 +1,371 @@
+---
+sidebar_label: Star Schema Benchmark
+description:  "Dataset based on the TPC-H dbgen source. The coding style and architecture
+follows the TPCH dbgen."
+---
+
+# Star Schema Benchmark 
+
+
+Compiling dbgen:
+
+``` bash
+$ git clone git@github.com:vadimtk/ssb-dbgen.git
+$ cd ssb-dbgen
+$ make
+```
+
+Generating data:
+
+:::warning    
+With `-s 100` dbgen generates 600 million rows (67 GB), while while `-s 1000` it generates 6 billion rows (which takes a lot of time)
+:::
+
+``` bash
+$ ./dbgen -s 1000 -T c
+$ ./dbgen -s 1000 -T l
+$ ./dbgen -s 1000 -T p
+$ ./dbgen -s 1000 -T s
+$ ./dbgen -s 1000 -T d
+```
+
+Creating tables in ClickHouse:
+
+``` sql
+CREATE TABLE customer
+(
+        C_CUSTKEY       UInt32,
+        C_NAME          String,
+        C_ADDRESS       String,
+        C_CITY          LowCardinality(String),
+        C_NATION        LowCardinality(String),
+        C_REGION        LowCardinality(String),
+        C_PHONE         String,
+        C_MKTSEGMENT    LowCardinality(String)
+)
+ENGINE = MergeTree ORDER BY (C_CUSTKEY);
+
+CREATE TABLE lineorder
+(
+    LO_ORDERKEY             UInt32,
+    LO_LINENUMBER           UInt8,
+    LO_CUSTKEY              UInt32,
+    LO_PARTKEY              UInt32,
+    LO_SUPPKEY              UInt32,
+    LO_ORDERDATE            Date,
+    LO_ORDERPRIORITY        LowCardinality(String),
+    LO_SHIPPRIORITY         UInt8,
+    LO_QUANTITY             UInt8,
+    LO_EXTENDEDPRICE        UInt32,
+    LO_ORDTOTALPRICE        UInt32,
+    LO_DISCOUNT             UInt8,
+    LO_REVENUE              UInt32,
+    LO_SUPPLYCOST           UInt32,
+    LO_TAX                  UInt8,
+    LO_COMMITDATE           Date,
+    LO_SHIPMODE             LowCardinality(String)
+)
+ENGINE = MergeTree PARTITION BY toYear(LO_ORDERDATE) ORDER BY (LO_ORDERDATE, LO_ORDERKEY);
+
+CREATE TABLE part
+(
+        P_PARTKEY       UInt32,
+        P_NAME          String,
+        P_MFGR          LowCardinality(String),
+        P_CATEGORY      LowCardinality(String),
+        P_BRAND         LowCardinality(String),
+        P_COLOR         LowCardinality(String),
+        P_TYPE          LowCardinality(String),
+        P_SIZE          UInt8,
+        P_CONTAINER     LowCardinality(String)
+)
+ENGINE = MergeTree ORDER BY P_PARTKEY;
+
+CREATE TABLE supplier
+(
+        S_SUPPKEY       UInt32,
+        S_NAME          String,
+        S_ADDRESS       String,
+        S_CITY          LowCardinality(String),
+        S_NATION        LowCardinality(String),
+        S_REGION        LowCardinality(String),
+        S_PHONE         String
+)
+ENGINE = MergeTree ORDER BY S_SUPPKEY;
+```
+
+Inserting data:
+
+``` bash
+$ clickhouse-client --query "INSERT INTO customer FORMAT CSV" < customer.tbl
+$ clickhouse-client --query "INSERT INTO part FORMAT CSV" < part.tbl
+$ clickhouse-client --query "INSERT INTO supplier FORMAT CSV" < supplier.tbl
+$ clickhouse-client --query "INSERT INTO lineorder FORMAT CSV" < lineorder.tbl
+```
+
+Converting “star schema” to denormalized “flat schema”:
+
+``` sql
+SET max_memory_usage = 20000000000;
+
+CREATE TABLE lineorder_flat
+ENGINE = MergeTree
+PARTITION BY toYear(LO_ORDERDATE)
+ORDER BY (LO_ORDERDATE, LO_ORDERKEY) AS
+SELECT
+    l.LO_ORDERKEY AS LO_ORDERKEY,
+    l.LO_LINENUMBER AS LO_LINENUMBER,
+    l.LO_CUSTKEY AS LO_CUSTKEY,
+    l.LO_PARTKEY AS LO_PARTKEY,
+    l.LO_SUPPKEY AS LO_SUPPKEY,
+    l.LO_ORDERDATE AS LO_ORDERDATE,
+    l.LO_ORDERPRIORITY AS LO_ORDERPRIORITY,
+    l.LO_SHIPPRIORITY AS LO_SHIPPRIORITY,
+    l.LO_QUANTITY AS LO_QUANTITY,
+    l.LO_EXTENDEDPRICE AS LO_EXTENDEDPRICE,
+    l.LO_ORDTOTALPRICE AS LO_ORDTOTALPRICE,
+    l.LO_DISCOUNT AS LO_DISCOUNT,
+    l.LO_REVENUE AS LO_REVENUE,
+    l.LO_SUPPLYCOST AS LO_SUPPLYCOST,
+    l.LO_TAX AS LO_TAX,
+    l.LO_COMMITDATE AS LO_COMMITDATE,
+    l.LO_SHIPMODE AS LO_SHIPMODE,
+    c.C_NAME AS C_NAME,
+    c.C_ADDRESS AS C_ADDRESS,
+    c.C_CITY AS C_CITY,
+    c.C_NATION AS C_NATION,
+    c.C_REGION AS C_REGION,
+    c.C_PHONE AS C_PHONE,
+    c.C_MKTSEGMENT AS C_MKTSEGMENT,
+    s.S_NAME AS S_NAME,
+    s.S_ADDRESS AS S_ADDRESS,
+    s.S_CITY AS S_CITY,
+    s.S_NATION AS S_NATION,
+    s.S_REGION AS S_REGION,
+    s.S_PHONE AS S_PHONE,
+    p.P_NAME AS P_NAME,
+    p.P_MFGR AS P_MFGR,
+    p.P_CATEGORY AS P_CATEGORY,
+    p.P_BRAND AS P_BRAND,
+    p.P_COLOR AS P_COLOR,
+    p.P_TYPE AS P_TYPE,
+    p.P_SIZE AS P_SIZE,
+    p.P_CONTAINER AS P_CONTAINER
+FROM lineorder AS l
+INNER JOIN customer AS c ON c.C_CUSTKEY = l.LO_CUSTKEY
+INNER JOIN supplier AS s ON s.S_SUPPKEY = l.LO_SUPPKEY
+INNER JOIN part AS p ON p.P_PARTKEY = l.LO_PARTKEY;
+```
+
+Running the queries:
+
+Q1.1
+
+``` sql
+SELECT sum(LO_EXTENDEDPRICE * LO_DISCOUNT) AS revenue
+FROM lineorder_flat
+WHERE toYear(LO_ORDERDATE) = 1993 AND LO_DISCOUNT BETWEEN 1 AND 3 AND LO_QUANTITY < 25;
+```
+
+Q1.2
+
+``` sql
+SELECT sum(LO_EXTENDEDPRICE * LO_DISCOUNT) AS revenue
+FROM lineorder_flat
+WHERE toYYYYMM(LO_ORDERDATE) = 199401 AND LO_DISCOUNT BETWEEN 4 AND 6 AND LO_QUANTITY BETWEEN 26 AND 35;
+```
+
+Q1.3
+
+``` sql
+SELECT sum(LO_EXTENDEDPRICE * LO_DISCOUNT) AS revenue
+FROM lineorder_flat
+WHERE toISOWeek(LO_ORDERDATE) = 6 AND toYear(LO_ORDERDATE) = 1994
+  AND LO_DISCOUNT BETWEEN 5 AND 7 AND LO_QUANTITY BETWEEN 26 AND 35;
+```
+
+Q2.1
+
+``` sql
+SELECT
+    sum(LO_REVENUE),
+    toYear(LO_ORDERDATE) AS year,
+    P_BRAND
+FROM lineorder_flat
+WHERE P_CATEGORY = 'MFGR#12' AND S_REGION = 'AMERICA'
+GROUP BY
+    year,
+    P_BRAND
+ORDER BY
+    year,
+    P_BRAND;
+```
+
+Q2.2
+
+``` sql
+SELECT
+    sum(LO_REVENUE),
+    toYear(LO_ORDERDATE) AS year,
+    P_BRAND
+FROM lineorder_flat
+WHERE P_BRAND >= 'MFGR#2221' AND P_BRAND <= 'MFGR#2228' AND S_REGION = 'ASIA'
+GROUP BY
+    year,
+    P_BRAND
+ORDER BY
+    year,
+    P_BRAND;
+```
+
+Q2.3
+
+``` sql
+SELECT
+    sum(LO_REVENUE),
+    toYear(LO_ORDERDATE) AS year,
+    P_BRAND
+FROM lineorder_flat
+WHERE P_BRAND = 'MFGR#2239' AND S_REGION = 'EUROPE'
+GROUP BY
+    year,
+    P_BRAND
+ORDER BY
+    year,
+    P_BRAND;
+```
+
+Q3.1
+
+``` sql
+SELECT
+    C_NATION,
+    S_NATION,
+    toYear(LO_ORDERDATE) AS year,
+    sum(LO_REVENUE) AS revenue
+FROM lineorder_flat
+WHERE C_REGION = 'ASIA' AND S_REGION = 'ASIA' AND year >= 1992 AND year <= 1997
+GROUP BY
+    C_NATION,
+    S_NATION,
+    year
+ORDER BY
+    year ASC,
+    revenue DESC;
+```
+
+Q3.2
+
+``` sql
+SELECT
+    C_CITY,
+    S_CITY,
+    toYear(LO_ORDERDATE) AS year,
+    sum(LO_REVENUE) AS revenue
+FROM lineorder_flat
+WHERE C_NATION = 'UNITED STATES' AND S_NATION = 'UNITED STATES' AND year >= 1992 AND year <= 1997
+GROUP BY
+    C_CITY,
+    S_CITY,
+    year
+ORDER BY
+    year ASC,
+    revenue DESC;
+```
+
+Q3.3
+
+``` sql
+SELECT
+    C_CITY,
+    S_CITY,
+    toYear(LO_ORDERDATE) AS year,
+    sum(LO_REVENUE) AS revenue
+FROM lineorder_flat
+WHERE (C_CITY = 'UNITED KI1' OR C_CITY = 'UNITED KI5') AND (S_CITY = 'UNITED KI1' OR S_CITY = 'UNITED KI5') AND year >= 1992 AND year <= 1997
+GROUP BY
+    C_CITY,
+    S_CITY,
+    year
+ORDER BY
+    year ASC,
+    revenue DESC;
+```
+
+Q3.4
+
+``` sql
+SELECT
+    C_CITY,
+    S_CITY,
+    toYear(LO_ORDERDATE) AS year,
+    sum(LO_REVENUE) AS revenue
+FROM lineorder_flat
+WHERE (C_CITY = 'UNITED KI1' OR C_CITY = 'UNITED KI5') AND (S_CITY = 'UNITED KI1' OR S_CITY = 'UNITED KI5') AND toYYYYMM(LO_ORDERDATE) = 199712
+GROUP BY
+    C_CITY,
+    S_CITY,
+    year
+ORDER BY
+    year ASC,
+    revenue DESC;
+```
+
+Q4.1
+
+``` sql
+SELECT
+    toYear(LO_ORDERDATE) AS year,
+    C_NATION,
+    sum(LO_REVENUE - LO_SUPPLYCOST) AS profit
+FROM lineorder_flat
+WHERE C_REGION = 'AMERICA' AND S_REGION = 'AMERICA' AND (P_MFGR = 'MFGR#1' OR P_MFGR = 'MFGR#2')
+GROUP BY
+    year,
+    C_NATION
+ORDER BY
+    year ASC,
+    C_NATION ASC;
+```
+
+Q4.2
+
+``` sql
+SELECT
+    toYear(LO_ORDERDATE) AS year,
+    S_NATION,
+    P_CATEGORY,
+    sum(LO_REVENUE - LO_SUPPLYCOST) AS profit
+FROM lineorder_flat
+WHERE C_REGION = 'AMERICA' AND S_REGION = 'AMERICA' AND (year = 1997 OR year = 1998) AND (P_MFGR = 'MFGR#1' OR P_MFGR = 'MFGR#2')
+GROUP BY
+    year,
+    S_NATION,
+    P_CATEGORY
+ORDER BY
+    year ASC,
+    S_NATION ASC,
+    P_CATEGORY ASC;
+```
+
+Q4.3
+
+``` sql
+SELECT
+    toYear(LO_ORDERDATE) AS year,
+    S_CITY,
+    P_BRAND,
+    sum(LO_REVENUE - LO_SUPPLYCOST) AS profit
+FROM lineorder_flat
+WHERE S_NATION = 'UNITED STATES' AND (year = 1997 OR year = 1998) AND P_CATEGORY = 'MFGR#14'
+GROUP BY
+    year,
+    S_CITY,
+    P_BRAND
+ORDER BY
+    year ASC,
+    S_CITY ASC,
+    P_BRAND ASC;
+```
+
+[Original article](https://clickhouse.com/docs/en/getting_started/example_datasets/star_schema/) <!--hide-->
diff --git a/docs/en/reference/getting-started/example-datasets/uk-price-paid.md b/docs/en/reference/getting-started/example-datasets/uk-price-paid.md
new file mode 100644
index 00000000000..e19e801dcf9
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/uk-price-paid.md
@@ -0,0 +1,648 @@
+---
+sidebar_label: UK Property Price Paid
+---
+
+# UK Property Price Paid
+
+The dataset contains data about prices paid for real-estate property in England and Wales. The data is available since year 1995.
+The size of the dataset in uncompressed form is about 4 GiB and it will take about 278 MiB in ClickHouse.
+
+Source: https://www.gov.uk/government/statistical-data-sets/price-paid-data-downloads
+Description of the fields: https://www.gov.uk/guidance/about-the-price-paid-data
+
+Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0.
+
+## Download the Dataset {#download-dataset}
+
+Run the command:
+
+```bash
+wget http://prod.publicdata.landregistry.gov.uk.s3-website-eu-west-1.amazonaws.com/pp-complete.csv
+```
+
+Download will take about 2 minutes with good internet connection.
+
+## Create the Table {#create-table}
+
+```sql
+CREATE TABLE uk_price_paid
+(
+    price UInt32,
+    date Date,
+    postcode1 LowCardinality(String),
+    postcode2 LowCardinality(String),
+    type Enum8('terraced' = 1, 'semi-detached' = 2, 'detached' = 3, 'flat' = 4, 'other' = 0),
+    is_new UInt8,
+    duration Enum8('freehold' = 1, 'leasehold' = 2, 'unknown' = 0),
+    addr1 String,
+    addr2 String,
+    street LowCardinality(String),
+    locality LowCardinality(String),
+    town LowCardinality(String),
+    district LowCardinality(String),
+    county LowCardinality(String),
+    category UInt8
+) ENGINE = MergeTree ORDER BY (postcode1, postcode2, addr1, addr2);
+```
+
+## Preprocess and Import Data {#preprocess-import-data}
+
+We will use `clickhouse-local` tool for data preprocessing and `clickhouse-client` to upload it.
+
+In this example, we define the structure of source data from the CSV file and specify a query to preprocess the data with `clickhouse-local`.
+
+The preprocessing is:
+- splitting the postcode to two different columns `postcode1` and `postcode2` that is better for storage and queries;
+- coverting the `time` field to date as it only contains 00:00 time;
+- ignoring the [UUid](../sql-reference/data-types/uuid.md) field because we don't need it for analysis;
+- transforming `type` and `duration` to more readable Enum fields with function [transform](../sql-reference/functions/other-functions.md#transform);
+- transforming `is_new` and `category` fields from single-character string (`Y`/`N` and `A`/`B`) to [UInt8](../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-uint256-int8-int16-int32-int64-int128-int256) field with 0 and 1.
+
+Preprocessed data is piped directly to `clickhouse-client` to be inserted into ClickHouse table in streaming fashion.
+
+```bash
+clickhouse-local --input-format CSV --structure '
+    uuid String,
+    price UInt32,
+    time DateTime,
+    postcode String,
+    a String,
+    b String,
+    c String,
+    addr1 String,
+    addr2 String,
+    street String,
+    locality String,
+    town String,
+    district String,
+    county String,
+    d String,
+    e String
+' --query "
+    WITH splitByChar(' ', postcode) AS p
+    SELECT
+        price,
+        toDate(time) AS date,
+        p[1] AS postcode1,
+        p[2] AS postcode2,
+        transform(a, ['T', 'S', 'D', 'F', 'O'], ['terraced', 'semi-detached', 'detached', 'flat', 'other']) AS type,
+        b = 'Y' AS is_new,
+        transform(c, ['F', 'L', 'U'], ['freehold', 'leasehold', 'unknown']) AS duration,
+        addr1,
+        addr2,
+        street,
+        locality,
+        town,
+        district,
+        county,
+        d = 'B' AS category
+    FROM table" --date_time_input_format best_effort < pp-complete.csv | clickhouse-client --query "INSERT INTO uk_price_paid FORMAT TSV"
+```
+
+It will take about 40 seconds.
+
+## Validate the Data {#validate-data}
+
+Query:
+
+```sql
+SELECT count() FROM uk_price_paid;
+```
+
+Result:
+
+```text
+┌──count()─┐
+│ 26321785 │
+└──────────┘
+```
+
+The size of dataset in ClickHouse is just 278 MiB, check it.
+
+Query:
+
+```sql
+SELECT formatReadableSize(total_bytes) FROM system.tables WHERE name = 'uk_price_paid';
+```
+
+Result:
+
+```text
+┌─formatReadableSize(total_bytes)─┐
+│ 278.80 MiB                      │
+└─────────────────────────────────┘
+```
+
+## Run Some Queries {#run-queries}
+
+### Query 1. Average Price Per Year {#average-price}
+
+Query:
+
+```sql
+SELECT toYear(date) AS year, round(avg(price)) AS price, bar(price, 0, 1000000, 80) FROM uk_price_paid GROUP BY year ORDER BY year;
+```
+
+Result:
+
+```text
+┌─year─┬──price─┬─bar(round(avg(price)), 0, 1000000, 80)─┐
+│ 1995 │  67932 │ █████▍                                 │
+│ 1996 │  71505 │ █████▋                                 │
+│ 1997 │  78532 │ ██████▎                                │
+│ 1998 │  85436 │ ██████▋                                │
+│ 1999 │  96037 │ ███████▋                               │
+│ 2000 │ 107479 │ ████████▌                              │
+│ 2001 │ 118885 │ █████████▌                             │
+│ 2002 │ 137941 │ ███████████                            │
+│ 2003 │ 155889 │ ████████████▍                          │
+│ 2004 │ 178885 │ ██████████████▎                        │
+│ 2005 │ 189351 │ ███████████████▏                       │
+│ 2006 │ 203528 │ ████████████████▎                      │
+│ 2007 │ 219378 │ █████████████████▌                     │
+│ 2008 │ 217056 │ █████████████████▎                     │
+│ 2009 │ 213419 │ █████████████████                      │
+│ 2010 │ 236109 │ ██████████████████▊                    │
+│ 2011 │ 232805 │ ██████████████████▌                    │
+│ 2012 │ 238367 │ ███████████████████                    │
+│ 2013 │ 256931 │ ████████████████████▌                  │
+│ 2014 │ 279915 │ ██████████████████████▍                │
+│ 2015 │ 297266 │ ███████████████████████▋               │
+│ 2016 │ 313201 │ █████████████████████████              │
+│ 2017 │ 346097 │ ███████████████████████████▋           │
+│ 2018 │ 350116 │ ████████████████████████████           │
+│ 2019 │ 351013 │ ████████████████████████████           │
+│ 2020 │ 369420 │ █████████████████████████████▌         │
+│ 2021 │ 386903 │ ██████████████████████████████▊        │
+└──────┴────────┴────────────────────────────────────────┘
+```
+
+### Query 2. Average Price per Year in London {#average-price-london}
+
+Query:
+
+```sql
+SELECT toYear(date) AS year, round(avg(price)) AS price, bar(price, 0, 2000000, 100) FROM uk_price_paid WHERE town = 'LONDON' GROUP BY year ORDER BY year;
+```
+
+Result:
+
+```text
+┌─year─┬───price─┬─bar(round(avg(price)), 0, 2000000, 100)───────────────┐
+│ 1995 │  109116 │ █████▍                                                │
+│ 1996 │  118667 │ █████▊                                                │
+│ 1997 │  136518 │ ██████▋                                               │
+│ 1998 │  152983 │ ███████▋                                              │
+│ 1999 │  180637 │ █████████                                             │
+│ 2000 │  215838 │ ██████████▋                                           │
+│ 2001 │  232994 │ ███████████▋                                          │
+│ 2002 │  263670 │ █████████████▏                                        │
+│ 2003 │  278394 │ █████████████▊                                        │
+│ 2004 │  304666 │ ███████████████▏                                      │
+│ 2005 │  322875 │ ████████████████▏                                     │
+│ 2006 │  356191 │ █████████████████▋                                    │
+│ 2007 │  404054 │ ████████████████████▏                                 │
+│ 2008 │  420741 │ █████████████████████                                 │
+│ 2009 │  427753 │ █████████████████████▍                                │
+│ 2010 │  480306 │ ████████████████████████                              │
+│ 2011 │  496274 │ ████████████████████████▋                             │
+│ 2012 │  519442 │ █████████████████████████▊                            │
+│ 2013 │  616212 │ ██████████████████████████████▋                       │
+│ 2014 │  724154 │ ████████████████████████████████████▏                 │
+│ 2015 │  792129 │ ███████████████████████████████████████▌              │
+│ 2016 │  843655 │ ██████████████████████████████████████████▏           │
+│ 2017 │  982642 │ █████████████████████████████████████████████████▏    │
+│ 2018 │ 1016835 │ ██████████████████████████████████████████████████▋   │
+│ 2019 │ 1042849 │ ████████████████████████████████████████████████████▏ │
+│ 2020 │ 1011889 │ ██████████████████████████████████████████████████▌   │
+│ 2021 │  960343 │ ████████████████████████████████████████████████      │
+└──────┴─────────┴───────────────────────────────────────────────────────┘
+```
+
+Something happened in 2013. I don't have a clue. Maybe you have a clue what happened in 2020?
+
+### Query 3. The Most Expensive Neighborhoods {#most-expensive-neighborhoods}
+
+Query:
+
+```sql
+SELECT
+    town,
+    district,
+    count() AS c,
+    round(avg(price)) AS price,
+    bar(price, 0, 5000000, 100)
+FROM uk_price_paid
+WHERE date >= '2020-01-01'
+GROUP BY
+    town,
+    district
+HAVING c >= 100
+ORDER BY price DESC
+LIMIT 100;
+```
+
+Result:
+
+```text
+
+┌─town─────────────────┬─district───────────────┬────c─┬───price─┬─bar(round(avg(price)), 0, 5000000, 100)────────────────────────────┐
+│ LONDON               │ CITY OF WESTMINSTER    │ 3606 │ 3280239 │ █████████████████████████████████████████████████████████████████▌ │
+│ LONDON               │ CITY OF LONDON         │  274 │ 3160502 │ ███████████████████████████████████████████████████████████████▏   │
+│ LONDON               │ KENSINGTON AND CHELSEA │ 2550 │ 2308478 │ ██████████████████████████████████████████████▏                    │
+│ LEATHERHEAD          │ ELMBRIDGE              │  114 │ 1897407 │ █████████████████████████████████████▊                             │
+│ LONDON               │ CAMDEN                 │ 3033 │ 1805404 │ ████████████████████████████████████                               │
+│ VIRGINIA WATER       │ RUNNYMEDE              │  156 │ 1753247 │ ███████████████████████████████████                                │
+│ WINDLESHAM           │ SURREY HEATH           │  108 │ 1677613 │ █████████████████████████████████▌                                 │
+│ THORNTON HEATH       │ CROYDON                │  546 │ 1671721 │ █████████████████████████████████▍                                 │
+│ BARNET               │ ENFIELD                │  124 │ 1505840 │ ██████████████████████████████                                     │
+│ COBHAM               │ ELMBRIDGE              │  387 │ 1237250 │ ████████████████████████▋                                          │
+│ LONDON               │ ISLINGTON              │ 2668 │ 1236980 │ ████████████████████████▋                                          │
+│ OXFORD               │ SOUTH OXFORDSHIRE      │  321 │ 1220907 │ ████████████████████████▍                                          │
+│ LONDON               │ RICHMOND UPON THAMES   │  704 │ 1215551 │ ████████████████████████▎                                          │
+│ LONDON               │ HOUNSLOW               │  671 │ 1207493 │ ████████████████████████▏                                          │
+│ ASCOT                │ WINDSOR AND MAIDENHEAD │  407 │ 1183299 │ ███████████████████████▋                                           │
+│ BEACONSFIELD         │ BUCKINGHAMSHIRE        │  330 │ 1175615 │ ███████████████████████▌                                           │
+│ RICHMOND             │ RICHMOND UPON THAMES   │  874 │ 1110444 │ ██████████████████████▏                                            │
+│ LONDON               │ HAMMERSMITH AND FULHAM │ 3086 │ 1053983 │ █████████████████████                                              │
+│ SURBITON             │ ELMBRIDGE              │  100 │ 1011800 │ ████████████████████▏                                              │
+│ RADLETT              │ HERTSMERE              │  283 │ 1011712 │ ████████████████████▏                                              │
+│ SALCOMBE             │ SOUTH HAMS             │  127 │ 1011624 │ ████████████████████▏                                              │
+│ WEYBRIDGE            │ ELMBRIDGE              │  655 │ 1007265 │ ████████████████████▏                                              │
+│ ESHER                │ ELMBRIDGE              │  485 │  986581 │ ███████████████████▋                                               │
+│ LEATHERHEAD          │ GUILDFORD              │  202 │  977320 │ ███████████████████▌                                               │
+│ BURFORD              │ WEST OXFORDSHIRE       │  111 │  966893 │ ███████████████████▎                                               │
+│ BROCKENHURST         │ NEW FOREST             │  129 │  956675 │ ███████████████████▏                                               │
+│ HINDHEAD             │ WAVERLEY               │  137 │  953753 │ ███████████████████                                                │
+│ GERRARDS CROSS       │ BUCKINGHAMSHIRE        │  419 │  951121 │ ███████████████████                                                │
+│ EAST MOLESEY         │ ELMBRIDGE              │  192 │  936769 │ ██████████████████▋                                                │
+│ CHALFONT ST GILES    │ BUCKINGHAMSHIRE        │  146 │  925515 │ ██████████████████▌                                                │
+│ LONDON               │ TOWER HAMLETS          │ 4388 │  918304 │ ██████████████████▎                                                │
+│ OLNEY                │ MILTON KEYNES          │  235 │  910646 │ ██████████████████▏                                                │
+│ HENLEY-ON-THAMES     │ SOUTH OXFORDSHIRE      │  540 │  902418 │ ██████████████████                                                 │
+│ LONDON               │ SOUTHWARK              │ 3885 │  892997 │ █████████████████▋                                                 │
+│ KINGSTON UPON THAMES │ KINGSTON UPON THAMES   │  960 │  885969 │ █████████████████▋                                                 │
+│ LONDON               │ EALING                 │ 2658 │  871755 │ █████████████████▍                                                 │
+│ CRANBROOK            │ TUNBRIDGE WELLS        │  431 │  862348 │ █████████████████▏                                                 │
+│ LONDON               │ MERTON                 │ 2099 │  859118 │ █████████████████▏                                                 │
+│ BELVEDERE            │ BEXLEY                 │  346 │  842423 │ ████████████████▋                                                  │
+│ GUILDFORD            │ WAVERLEY               │  143 │  841277 │ ████████████████▋                                                  │
+│ HARPENDEN            │ ST ALBANS              │  657 │  841216 │ ████████████████▋                                                  │
+│ LONDON               │ HACKNEY                │ 3307 │  837090 │ ████████████████▋                                                  │
+│ LONDON               │ WANDSWORTH             │ 6566 │  832663 │ ████████████████▋                                                  │
+│ MAIDENHEAD           │ BUCKINGHAMSHIRE        │  123 │  824299 │ ████████████████▍                                                  │
+│ KINGS LANGLEY        │ DACORUM                │  145 │  821331 │ ████████████████▍                                                  │
+│ BERKHAMSTED          │ DACORUM                │  543 │  818415 │ ████████████████▎                                                  │
+│ GREAT MISSENDEN      │ BUCKINGHAMSHIRE        │  226 │  802807 │ ████████████████                                                   │
+│ BILLINGSHURST        │ CHICHESTER             │  144 │  797829 │ ███████████████▊                                                   │
+│ WOKING               │ GUILDFORD              │  176 │  793494 │ ███████████████▋                                                   │
+│ STOCKBRIDGE          │ TEST VALLEY            │  178 │  793269 │ ███████████████▋                                                   │
+│ EPSOM                │ REIGATE AND BANSTEAD   │  172 │  791862 │ ███████████████▋                                                   │
+│ TONBRIDGE            │ TUNBRIDGE WELLS        │  360 │  787876 │ ███████████████▋                                                   │
+│ TEDDINGTON           │ RICHMOND UPON THAMES   │  595 │  786492 │ ███████████████▋                                                   │
+│ TWICKENHAM           │ RICHMOND UPON THAMES   │ 1155 │  786193 │ ███████████████▋                                                   │
+│ LYNDHURST            │ NEW FOREST             │  102 │  785593 │ ███████████████▋                                                   │
+│ LONDON               │ LAMBETH                │ 5228 │  774574 │ ███████████████▍                                                   │
+│ LONDON               │ BARNET                 │ 3955 │  773259 │ ███████████████▍                                                   │
+│ OXFORD               │ VALE OF WHITE HORSE    │  353 │  772088 │ ███████████████▍                                                   │
+│ TONBRIDGE            │ MAIDSTONE              │  305 │  770740 │ ███████████████▍                                                   │
+│ LUTTERWORTH          │ HARBOROUGH             │  538 │  768634 │ ███████████████▎                                                   │
+│ WOODSTOCK            │ WEST OXFORDSHIRE       │  140 │  766037 │ ███████████████▎                                                   │
+│ MIDHURST             │ CHICHESTER             │  257 │  764815 │ ███████████████▎                                                   │
+│ MARLOW               │ BUCKINGHAMSHIRE        │  327 │  761876 │ ███████████████▏                                                   │
+│ LONDON               │ NEWHAM                 │ 3237 │  761784 │ ███████████████▏                                                   │
+│ ALDERLEY EDGE        │ CHESHIRE EAST          │  178 │  757318 │ ███████████████▏                                                   │
+│ LUTON                │ CENTRAL BEDFORDSHIRE   │  212 │  754283 │ ███████████████                                                    │
+│ PETWORTH             │ CHICHESTER             │  154 │  754220 │ ███████████████                                                    │
+│ ALRESFORD            │ WINCHESTER             │  219 │  752718 │ ███████████████                                                    │
+│ POTTERS BAR          │ WELWYN HATFIELD        │  174 │  748465 │ ██████████████▊                                                    │
+│ HASLEMERE            │ CHICHESTER             │  128 │  746907 │ ██████████████▊                                                    │
+│ TADWORTH             │ REIGATE AND BANSTEAD   │  502 │  743252 │ ██████████████▋                                                    │
+│ THAMES DITTON        │ ELMBRIDGE              │  244 │  741913 │ ██████████████▋                                                    │
+│ REIGATE              │ REIGATE AND BANSTEAD   │  581 │  738198 │ ██████████████▋                                                    │
+│ BOURNE END           │ BUCKINGHAMSHIRE        │  138 │  735190 │ ██████████████▋                                                    │
+│ SEVENOAKS            │ SEVENOAKS              │ 1156 │  730018 │ ██████████████▌                                                    │
+│ OXTED                │ TANDRIDGE              │  336 │  729123 │ ██████████████▌                                                    │
+│ INGATESTONE          │ BRENTWOOD              │  166 │  728103 │ ██████████████▌                                                    │
+│ LONDON               │ BRENT                  │ 2079 │  720605 │ ██████████████▍                                                    │
+│ LONDON               │ HARINGEY               │ 3216 │  717780 │ ██████████████▎                                                    │
+│ PURLEY               │ CROYDON                │  575 │  716108 │ ██████████████▎                                                    │
+│ WELWYN               │ WELWYN HATFIELD        │  222 │  710603 │ ██████████████▏                                                    │
+│ RICKMANSWORTH        │ THREE RIVERS           │  798 │  704571 │ ██████████████                                                     │
+│ BANSTEAD             │ REIGATE AND BANSTEAD   │  401 │  701293 │ ██████████████                                                     │
+│ CHIGWELL             │ EPPING FOREST          │  261 │  701203 │ ██████████████                                                     │
+│ PINNER               │ HARROW                 │  528 │  698885 │ █████████████▊                                                     │
+│ HASLEMERE            │ WAVERLEY               │  280 │  696659 │ █████████████▊                                                     │
+│ SLOUGH               │ BUCKINGHAMSHIRE        │  396 │  694917 │ █████████████▊                                                     │
+│ WALTON-ON-THAMES     │ ELMBRIDGE              │  946 │  692395 │ █████████████▋                                                     │
+│ READING              │ SOUTH OXFORDSHIRE      │  318 │  691988 │ █████████████▋                                                     │
+│ NORTHWOOD            │ HILLINGDON             │  271 │  690643 │ █████████████▋                                                     │
+│ FELTHAM              │ HOUNSLOW               │  763 │  688595 │ █████████████▋                                                     │
+│ ASHTEAD              │ MOLE VALLEY            │  303 │  687923 │ █████████████▋                                                     │
+│ BARNET               │ BARNET                 │  975 │  686980 │ █████████████▋                                                     │
+│ WOKING               │ SURREY HEATH           │  283 │  686669 │ █████████████▋                                                     │
+│ MALMESBURY           │ WILTSHIRE              │  323 │  683324 │ █████████████▋                                                     │
+│ AMERSHAM             │ BUCKINGHAMSHIRE        │  496 │  680962 │ █████████████▌                                                     │
+│ CHISLEHURST          │ BROMLEY                │  430 │  680209 │ █████████████▌                                                     │
+│ HYTHE                │ FOLKESTONE AND HYTHE   │  490 │  676908 │ █████████████▌                                                     │
+│ MAYFIELD             │ WEALDEN                │  101 │  676210 │ █████████████▌                                                     │
+│ ASCOT                │ BRACKNELL FOREST       │  168 │  676004 │ █████████████▌                                                     │
+└──────────────────────┴────────────────────────┴──────┴─────────┴────────────────────────────────────────────────────────────────────┘
+```
+
+## Let's Speed Up Queries Using Projections {#speedup-with-projections}
+
+[Projections](../sql-reference/statements/alter/projection.md) allow to improve queries speed by storing pre-aggregated data.
+
+### Build a Projection {#build-projection}
+
+Create an aggregate projection by dimensions `toYear(date)`, `district`, `town`:
+
+```sql
+ALTER TABLE uk_price_paid
+    ADD PROJECTION projection_by_year_district_town
+    (
+        SELECT
+            toYear(date),
+            district,
+            town,
+            avg(price),
+            sum(price),
+            count()
+        GROUP BY
+            toYear(date),
+            district,
+            town
+    );
+```
+
+Populate the projection for existing data (without it projection will be created for only newly inserted data):
+
+```sql
+ALTER TABLE uk_price_paid
+    MATERIALIZE PROJECTION projection_by_year_district_town
+SETTINGS mutations_sync = 1;
+```
+
+## Test Performance {#test-performance}
+
+Let's run the same 3 queries.
+
+[Enable](../operations/settings/settings.md#allow-experimental-projection-optimization) projections for selects:
+
+```sql
+SET allow_experimental_projection_optimization = 1;
+```
+
+### Query 1. Average Price Per Year {#average-price-projections}
+
+Query:
+
+```sql
+SELECT
+    toYear(date) AS year,
+    round(avg(price)) AS price,
+    bar(price, 0, 1000000, 80)
+FROM uk_price_paid
+GROUP BY year
+ORDER BY year ASC;
+```
+
+Result:
+
+```text
+┌─year─┬──price─┬─bar(round(avg(price)), 0, 1000000, 80)─┐
+│ 1995 │  67932 │ █████▍                                 │
+│ 1996 │  71505 │ █████▋                                 │
+│ 1997 │  78532 │ ██████▎                                │
+│ 1998 │  85436 │ ██████▋                                │
+│ 1999 │  96037 │ ███████▋                               │
+│ 2000 │ 107479 │ ████████▌                              │
+│ 2001 │ 118885 │ █████████▌                             │
+│ 2002 │ 137941 │ ███████████                            │
+│ 2003 │ 155889 │ ████████████▍                          │
+│ 2004 │ 178885 │ ██████████████▎                        │
+│ 2005 │ 189351 │ ███████████████▏                       │
+│ 2006 │ 203528 │ ████████████████▎                      │
+│ 2007 │ 219378 │ █████████████████▌                     │
+│ 2008 │ 217056 │ █████████████████▎                     │
+│ 2009 │ 213419 │ █████████████████                      │
+│ 2010 │ 236109 │ ██████████████████▊                    │
+│ 2011 │ 232805 │ ██████████████████▌                    │
+│ 2012 │ 238367 │ ███████████████████                    │
+│ 2013 │ 256931 │ ████████████████████▌                  │
+│ 2014 │ 279915 │ ██████████████████████▍                │
+│ 2015 │ 297266 │ ███████████████████████▋               │
+│ 2016 │ 313201 │ █████████████████████████              │
+│ 2017 │ 346097 │ ███████████████████████████▋           │
+│ 2018 │ 350116 │ ████████████████████████████           │
+│ 2019 │ 351013 │ ████████████████████████████           │
+│ 2020 │ 369420 │ █████████████████████████████▌         │
+│ 2021 │ 386903 │ ██████████████████████████████▊        │
+└──────┴────────┴────────────────────────────────────────┘
+```
+
+### Query 2. Average Price Per Year in London {#average-price-london-projections}
+
+Query:
+
+```sql
+SELECT
+    toYear(date) AS year,
+    round(avg(price)) AS price,
+    bar(price, 0, 2000000, 100)
+FROM uk_price_paid
+WHERE town = 'LONDON'
+GROUP BY year
+ORDER BY year ASC;
+```
+
+Result:
+
+```text
+┌─year─┬───price─┬─bar(round(avg(price)), 0, 2000000, 100)───────────────┐
+│ 1995 │  109116 │ █████▍                                                │
+│ 1996 │  118667 │ █████▊                                                │
+│ 1997 │  136518 │ ██████▋                                               │
+│ 1998 │  152983 │ ███████▋                                              │
+│ 1999 │  180637 │ █████████                                             │
+│ 2000 │  215838 │ ██████████▋                                           │
+│ 2001 │  232994 │ ███████████▋                                          │
+│ 2002 │  263670 │ █████████████▏                                        │
+│ 2003 │  278394 │ █████████████▊                                        │
+│ 2004 │  304666 │ ███████████████▏                                      │
+│ 2005 │  322875 │ ████████████████▏                                     │
+│ 2006 │  356191 │ █████████████████▋                                    │
+│ 2007 │  404054 │ ████████████████████▏                                 │
+│ 2008 │  420741 │ █████████████████████                                 │
+│ 2009 │  427753 │ █████████████████████▍                                │
+│ 2010 │  480306 │ ████████████████████████                              │
+│ 2011 │  496274 │ ████████████████████████▋                             │
+│ 2012 │  519442 │ █████████████████████████▊                            │
+│ 2013 │  616212 │ ██████████████████████████████▋                       │
+│ 2014 │  724154 │ ████████████████████████████████████▏                 │
+│ 2015 │  792129 │ ███████████████████████████████████████▌              │
+│ 2016 │  843655 │ ██████████████████████████████████████████▏           │
+│ 2017 │  982642 │ █████████████████████████████████████████████████▏    │
+│ 2018 │ 1016835 │ ██████████████████████████████████████████████████▋   │
+│ 2019 │ 1042849 │ ████████████████████████████████████████████████████▏ │
+│ 2020 │ 1011889 │ ██████████████████████████████████████████████████▌   │
+│ 2021 │  960343 │ ████████████████████████████████████████████████      │
+└──────┴─────────┴───────────────────────────────────────────────────────┘
+```
+
+### Query 3. The Most Expensive Neighborhoods {#most-expensive-neighborhoods-projections}
+
+The condition (date >= '2020-01-01') needs to be modified to match projection dimension (toYear(date) >= 2020).
+
+Query:
+
+```sql
+SELECT
+    town,
+    district,
+    count() AS c,
+    round(avg(price)) AS price,
+    bar(price, 0, 5000000, 100)
+FROM uk_price_paid
+WHERE toYear(date) >= 2020
+GROUP BY
+    town,
+    district
+HAVING c >= 100
+ORDER BY price DESC
+LIMIT 100;
+```
+
+Result:
+
+```text
+┌─town─────────────────┬─district───────────────┬────c─┬───price─┬─bar(round(avg(price)), 0, 5000000, 100)────────────────────────────┐
+│ LONDON               │ CITY OF WESTMINSTER    │ 3606 │ 3280239 │ █████████████████████████████████████████████████████████████████▌ │
+│ LONDON               │ CITY OF LONDON         │  274 │ 3160502 │ ███████████████████████████████████████████████████████████████▏   │
+│ LONDON               │ KENSINGTON AND CHELSEA │ 2550 │ 2308478 │ ██████████████████████████████████████████████▏                    │
+│ LEATHERHEAD          │ ELMBRIDGE              │  114 │ 1897407 │ █████████████████████████████████████▊                             │
+│ LONDON               │ CAMDEN                 │ 3033 │ 1805404 │ ████████████████████████████████████                               │
+│ VIRGINIA WATER       │ RUNNYMEDE              │  156 │ 1753247 │ ███████████████████████████████████                                │
+│ WINDLESHAM           │ SURREY HEATH           │  108 │ 1677613 │ █████████████████████████████████▌                                 │
+│ THORNTON HEATH       │ CROYDON                │  546 │ 1671721 │ █████████████████████████████████▍                                 │
+│ BARNET               │ ENFIELD                │  124 │ 1505840 │ ██████████████████████████████                                     │
+│ COBHAM               │ ELMBRIDGE              │  387 │ 1237250 │ ████████████████████████▋                                          │
+│ LONDON               │ ISLINGTON              │ 2668 │ 1236980 │ ████████████████████████▋                                          │
+│ OXFORD               │ SOUTH OXFORDSHIRE      │  321 │ 1220907 │ ████████████████████████▍                                          │
+│ LONDON               │ RICHMOND UPON THAMES   │  704 │ 1215551 │ ████████████████████████▎                                          │
+│ LONDON               │ HOUNSLOW               │  671 │ 1207493 │ ████████████████████████▏                                          │
+│ ASCOT                │ WINDSOR AND MAIDENHEAD │  407 │ 1183299 │ ███████████████████████▋                                           │
+│ BEACONSFIELD         │ BUCKINGHAMSHIRE        │  330 │ 1175615 │ ███████████████████████▌                                           │
+│ RICHMOND             │ RICHMOND UPON THAMES   │  874 │ 1110444 │ ██████████████████████▏                                            │
+│ LONDON               │ HAMMERSMITH AND FULHAM │ 3086 │ 1053983 │ █████████████████████                                              │
+│ SURBITON             │ ELMBRIDGE              │  100 │ 1011800 │ ████████████████████▏                                              │
+│ RADLETT              │ HERTSMERE              │  283 │ 1011712 │ ████████████████████▏                                              │
+│ SALCOMBE             │ SOUTH HAMS             │  127 │ 1011624 │ ████████████████████▏                                              │
+│ WEYBRIDGE            │ ELMBRIDGE              │  655 │ 1007265 │ ████████████████████▏                                              │
+│ ESHER                │ ELMBRIDGE              │  485 │  986581 │ ███████████████████▋                                               │
+│ LEATHERHEAD          │ GUILDFORD              │  202 │  977320 │ ███████████████████▌                                               │
+│ BURFORD              │ WEST OXFORDSHIRE       │  111 │  966893 │ ███████████████████▎                                               │
+│ BROCKENHURST         │ NEW FOREST             │  129 │  956675 │ ███████████████████▏                                               │
+│ HINDHEAD             │ WAVERLEY               │  137 │  953753 │ ███████████████████                                                │
+│ GERRARDS CROSS       │ BUCKINGHAMSHIRE        │  419 │  951121 │ ███████████████████                                                │
+│ EAST MOLESEY         │ ELMBRIDGE              │  192 │  936769 │ ██████████████████▋                                                │
+│ CHALFONT ST GILES    │ BUCKINGHAMSHIRE        │  146 │  925515 │ ██████████████████▌                                                │
+│ LONDON               │ TOWER HAMLETS          │ 4388 │  918304 │ ██████████████████▎                                                │
+│ OLNEY                │ MILTON KEYNES          │  235 │  910646 │ ██████████████████▏                                                │
+│ HENLEY-ON-THAMES     │ SOUTH OXFORDSHIRE      │  540 │  902418 │ ██████████████████                                                 │
+│ LONDON               │ SOUTHWARK              │ 3885 │  892997 │ █████████████████▋                                                 │
+│ KINGSTON UPON THAMES │ KINGSTON UPON THAMES   │  960 │  885969 │ █████████████████▋                                                 │
+│ LONDON               │ EALING                 │ 2658 │  871755 │ █████████████████▍                                                 │
+│ CRANBROOK            │ TUNBRIDGE WELLS        │  431 │  862348 │ █████████████████▏                                                 │
+│ LONDON               │ MERTON                 │ 2099 │  859118 │ █████████████████▏                                                 │
+│ BELVEDERE            │ BEXLEY                 │  346 │  842423 │ ████████████████▋                                                  │
+│ GUILDFORD            │ WAVERLEY               │  143 │  841277 │ ████████████████▋                                                  │
+│ HARPENDEN            │ ST ALBANS              │  657 │  841216 │ ████████████████▋                                                  │
+│ LONDON               │ HACKNEY                │ 3307 │  837090 │ ████████████████▋                                                  │
+│ LONDON               │ WANDSWORTH             │ 6566 │  832663 │ ████████████████▋                                                  │
+│ MAIDENHEAD           │ BUCKINGHAMSHIRE        │  123 │  824299 │ ████████████████▍                                                  │
+│ KINGS LANGLEY        │ DACORUM                │  145 │  821331 │ ████████████████▍                                                  │
+│ BERKHAMSTED          │ DACORUM                │  543 │  818415 │ ████████████████▎                                                  │
+│ GREAT MISSENDEN      │ BUCKINGHAMSHIRE        │  226 │  802807 │ ████████████████                                                   │
+│ BILLINGSHURST        │ CHICHESTER             │  144 │  797829 │ ███████████████▊                                                   │
+│ WOKING               │ GUILDFORD              │  176 │  793494 │ ███████████████▋                                                   │
+│ STOCKBRIDGE          │ TEST VALLEY            │  178 │  793269 │ ███████████████▋                                                   │
+│ EPSOM                │ REIGATE AND BANSTEAD   │  172 │  791862 │ ███████████████▋                                                   │
+│ TONBRIDGE            │ TUNBRIDGE WELLS        │  360 │  787876 │ ███████████████▋                                                   │
+│ TEDDINGTON           │ RICHMOND UPON THAMES   │  595 │  786492 │ ███████████████▋                                                   │
+│ TWICKENHAM           │ RICHMOND UPON THAMES   │ 1155 │  786193 │ ███████████████▋                                                   │
+│ LYNDHURST            │ NEW FOREST             │  102 │  785593 │ ███████████████▋                                                   │
+│ LONDON               │ LAMBETH                │ 5228 │  774574 │ ███████████████▍                                                   │
+│ LONDON               │ BARNET                 │ 3955 │  773259 │ ███████████████▍                                                   │
+│ OXFORD               │ VALE OF WHITE HORSE    │  353 │  772088 │ ███████████████▍                                                   │
+│ TONBRIDGE            │ MAIDSTONE              │  305 │  770740 │ ███████████████▍                                                   │
+│ LUTTERWORTH          │ HARBOROUGH             │  538 │  768634 │ ███████████████▎                                                   │
+│ WOODSTOCK            │ WEST OXFORDSHIRE       │  140 │  766037 │ ███████████████▎                                                   │
+│ MIDHURST             │ CHICHESTER             │  257 │  764815 │ ███████████████▎                                                   │
+│ MARLOW               │ BUCKINGHAMSHIRE        │  327 │  761876 │ ███████████████▏                                                   │
+│ LONDON               │ NEWHAM                 │ 3237 │  761784 │ ███████████████▏                                                   │
+│ ALDERLEY EDGE        │ CHESHIRE EAST          │  178 │  757318 │ ███████████████▏                                                   │
+│ LUTON                │ CENTRAL BEDFORDSHIRE   │  212 │  754283 │ ███████████████                                                    │
+│ PETWORTH             │ CHICHESTER             │  154 │  754220 │ ███████████████                                                    │
+│ ALRESFORD            │ WINCHESTER             │  219 │  752718 │ ███████████████                                                    │
+│ POTTERS BAR          │ WELWYN HATFIELD        │  174 │  748465 │ ██████████████▊                                                    │
+│ HASLEMERE            │ CHICHESTER             │  128 │  746907 │ ██████████████▊                                                    │
+│ TADWORTH             │ REIGATE AND BANSTEAD   │  502 │  743252 │ ██████████████▋                                                    │
+│ THAMES DITTON        │ ELMBRIDGE              │  244 │  741913 │ ██████████████▋                                                    │
+│ REIGATE              │ REIGATE AND BANSTEAD   │  581 │  738198 │ ██████████████▋                                                    │
+│ BOURNE END           │ BUCKINGHAMSHIRE        │  138 │  735190 │ ██████████████▋                                                    │
+│ SEVENOAKS            │ SEVENOAKS              │ 1156 │  730018 │ ██████████████▌                                                    │
+│ OXTED                │ TANDRIDGE              │  336 │  729123 │ ██████████████▌                                                    │
+│ INGATESTONE          │ BRENTWOOD              │  166 │  728103 │ ██████████████▌                                                    │
+│ LONDON               │ BRENT                  │ 2079 │  720605 │ ██████████████▍                                                    │
+│ LONDON               │ HARINGEY               │ 3216 │  717780 │ ██████████████▎                                                    │
+│ PURLEY               │ CROYDON                │  575 │  716108 │ ██████████████▎                                                    │
+│ WELWYN               │ WELWYN HATFIELD        │  222 │  710603 │ ██████████████▏                                                    │
+│ RICKMANSWORTH        │ THREE RIVERS           │  798 │  704571 │ ██████████████                                                     │
+│ BANSTEAD             │ REIGATE AND BANSTEAD   │  401 │  701293 │ ██████████████                                                     │
+│ CHIGWELL             │ EPPING FOREST          │  261 │  701203 │ ██████████████                                                     │
+│ PINNER               │ HARROW                 │  528 │  698885 │ █████████████▊                                                     │
+│ HASLEMERE            │ WAVERLEY               │  280 │  696659 │ █████████████▊                                                     │
+│ SLOUGH               │ BUCKINGHAMSHIRE        │  396 │  694917 │ █████████████▊                                                     │
+│ WALTON-ON-THAMES     │ ELMBRIDGE              │  946 │  692395 │ █████████████▋                                                     │
+│ READING              │ SOUTH OXFORDSHIRE      │  318 │  691988 │ █████████████▋                                                     │
+│ NORTHWOOD            │ HILLINGDON             │  271 │  690643 │ █████████████▋                                                     │
+│ FELTHAM              │ HOUNSLOW               │  763 │  688595 │ █████████████▋                                                     │
+│ ASHTEAD              │ MOLE VALLEY            │  303 │  687923 │ █████████████▋                                                     │
+│ BARNET               │ BARNET                 │  975 │  686980 │ █████████████▋                                                     │
+│ WOKING               │ SURREY HEATH           │  283 │  686669 │ █████████████▋                                                     │
+│ MALMESBURY           │ WILTSHIRE              │  323 │  683324 │ █████████████▋                                                     │
+│ AMERSHAM             │ BUCKINGHAMSHIRE        │  496 │  680962 │ █████████████▌                                                     │
+│ CHISLEHURST          │ BROMLEY                │  430 │  680209 │ █████████████▌                                                     │
+│ HYTHE                │ FOLKESTONE AND HYTHE   │  490 │  676908 │ █████████████▌                                                     │
+│ MAYFIELD             │ WEALDEN                │  101 │  676210 │ █████████████▌                                                     │
+│ ASCOT                │ BRACKNELL FOREST       │  168 │  676004 │ █████████████▌                                                     │
+└──────────────────────┴────────────────────────┴──────┴─────────┴────────────────────────────────────────────────────────────────────┘
+```
+
+### Summary {#summary}
+
+All 3 queries work much faster and read fewer rows.
+
+```text
+Query 1
+
+no projection: 27 rows in set. Elapsed: 0.158 sec. Processed 26.32 million rows, 157.93 MB (166.57 million rows/s., 999.39 MB/s.)
+   projection: 27 rows in set. Elapsed: 0.007 sec. Processed 105.96 thousand rows, 3.33 MB (14.58 million rows/s., 458.13 MB/s.)
+
+
+Query 2
+
+no projection: 27 rows in set. Elapsed: 0.163 sec. Processed 26.32 million rows, 80.01 MB (161.75 million rows/s., 491.64 MB/s.)
+   projection: 27 rows in set. Elapsed: 0.008 sec. Processed 105.96 thousand rows, 3.67 MB (13.29 million rows/s., 459.89 MB/s.)
+
+Query 3
+
+no projection: 100 rows in set. Elapsed: 0.069 sec. Processed 26.32 million rows, 62.47 MB (382.13 million rows/s., 906.93 MB/s.)
+   projection: 100 rows in set. Elapsed: 0.029 sec. Processed 8.08 thousand rows, 511.08 KB (276.06 thousand rows/s., 17.47 MB/s.)
+```
+
+### Test It in Playground {#playground}
+
+The dataset is also available in the [Online Playground](https://gh-api.clickhouse.com/play?user=play#U0VMRUNUIHRvd24sIGRpc3RyaWN0LCBjb3VudCgpIEFTIGMsIHJvdW5kKGF2ZyhwcmljZSkpIEFTIHByaWNlLCBiYXIocHJpY2UsIDAsIDUwMDAwMDAsIDEwMCkgRlJPTSB1a19wcmljZV9wYWlkIFdIRVJFIGRhdGUgPj0gJzIwMjAtMDEtMDEnIEdST1VQIEJZIHRvd24sIGRpc3RyaWN0IEhBVklORyBjID49IDEwMCBPUkRFUiBCWSBwcmljZSBERVNDIExJTUlUIDEwMA==).
diff --git a/docs/en/reference/getting-started/example-datasets/wikistat.md b/docs/en/reference/getting-started/example-datasets/wikistat.md
new file mode 100644
index 00000000000..1185338a1da
--- /dev/null
+++ b/docs/en/reference/getting-started/example-datasets/wikistat.md
@@ -0,0 +1,32 @@
+---
+sidebar_label: WikiStat
+---
+
+# WikiStat
+
+See http://dumps.wikimedia.org/other/pagecounts-raw/ for details.
+
+Creating a table:
+
+``` sql
+CREATE TABLE wikistat
+(
+    date Date,
+    time DateTime,
+    project String,
+    subproject String,
+    path String,
+    hits UInt64,
+    size UInt64
+) ENGINE = MergeTree(date, (path, time), 8192);
+```
+
+Loading data:
+
+``` bash
+$ for i in {2007..2016}; do for j in {01..12}; do echo $i-$j >&2; curl -sSL "http://dumps.wikimedia.org/other/pagecounts-raw/$i/$i-$j/" | grep -oE 'pagecounts-[0-9]+-[0-9]+\.gz'; done; done | sort | uniq | tee links.txt
+$ cat links.txt | while read link; do wget http://dumps.wikimedia.org/other/pagecounts-raw/$(echo $link | sed -r 's/pagecounts-([0-9]{4})([0-9]{2})[0-9]{2}-[0-9]+\.gz/\1/')/$(echo $link | sed -r 's/pagecounts-([0-9]{4})([0-9]{2})[0-9]{2}-[0-9]+\.gz/\1-\2/')/$link; done
+$ ls -1 /opt/wikistat/ | grep gz | while read i; do echo $i; gzip -cd /opt/wikistat/$i | ./wikistat-loader --time="$(echo -n $i | sed -r 's/pagecounts-([0-9]{4})([0-9]{2})([0-9]{2})-([0-9]{2})([0-9]{2})([0-9]{2})\.gz/\1-\2-\3 \4-00-00/')" | clickhouse-client --query="INSERT INTO wikistat FORMAT TabSeparated"; done
+```
+
+[Original article](https://clickhouse.com/docs/en/getting_started/example_datasets/wikistat/) <!--hide-->
diff --git a/docs/en/reference/getting-started/install.md b/docs/en/reference/getting-started/install.md
new file mode 100644
index 00000000000..5682e2a0861
--- /dev/null
+++ b/docs/en/reference/getting-started/install.md
@@ -0,0 +1,312 @@
+---
+sidebar_label: Installation
+sidebar_position: 1
+keywords: [clickhouse, install, installation, docs]
+description: ClickHouse can run on any Linux, FreeBSD, or Mac OS X with x86_64, AArch64, or PowerPC64LE CPU architecture.
+slug: /en/getting-started/install
+---
+
+# Installation {#installation}
+
+## System Requirements {#system-requirements}
+
+ClickHouse can run on any Linux, FreeBSD, or Mac OS X with x86_64, AArch64, or PowerPC64LE CPU architecture.
+
+Official pre-built binaries are typically compiled for x86_64 and leverage SSE 4.2 instruction set, so unless otherwise stated usage of CPU that supports it becomes an additional system requirement. Here’s the command to check if current CPU has support for SSE 4.2:
+
+``` bash
+$ grep -q sse4_2 /proc/cpuinfo && echo "SSE 4.2 supported" || echo "SSE 4.2 not supported"
+```
+
+To run ClickHouse on processors that do not support SSE 4.2 or have AArch64 or PowerPC64LE architecture, you should [build ClickHouse from sources](#from-sources) with proper configuration adjustments.
+
+## Available Installation Options {#available-installation-options}
+
+### From DEB Packages {#install-from-deb-packages}
+
+It is recommended to use official pre-compiled `deb` packages for Debian or Ubuntu. Run these commands to install packages:
+
+``` bash
+sudo apt-get install -y apt-transport-https ca-certificates dirmngr
+sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 8919F6BD2B48D754
+
+echo "deb https://packages.clickhouse.com/deb stable main" | sudo tee \
+    /etc/apt/sources.list.d/clickhouse.list
+sudo apt-get update
+
+sudo apt-get install -y clickhouse-server clickhouse-client
+
+sudo service clickhouse-server start
+clickhouse-client # or "clickhouse-client --password" if you've set up a password.
+```
+
+<details>
+<summary>Deprecated Method for installing deb-packages</summary>
+
+``` bash
+sudo apt-get install apt-transport-https ca-certificates dirmngr
+sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv E0C56BD4
+
+echo "deb https://repo.clickhouse.com/deb/stable/ main/" | sudo tee \
+    /etc/apt/sources.list.d/clickhouse.list
+sudo apt-get update
+
+sudo apt-get install -y clickhouse-server clickhouse-client
+
+sudo service clickhouse-server start
+clickhouse-client # or "clickhouse-client --password" if you set up a password.
+```
+
+</details>
+
+You can replace `stable` with `lts` or `testing` to use different [release trains](../faq/operations/production.md) based on your needs.
+
+You can also download and install packages manually from [here](https://packages.clickhouse.com/deb/pool/stable).
+
+#### Packages {#packages}
+
+-   `clickhouse-common-static` — Installs ClickHouse compiled binary files.
+-   `clickhouse-server` — Creates a symbolic link for `clickhouse-server` and installs the default server configuration.
+-   `clickhouse-client` — Creates a symbolic link for `clickhouse-client` and other client-related tools. and installs client configuration files.
+-   `clickhouse-common-static-dbg` — Installs ClickHouse compiled binary files with debug info.
+
+:::info    
+If you need to install specific version of ClickHouse you have to install all packages with the same version:
+`sudo apt-get install clickhouse-server=21.8.5.7 clickhouse-client=21.8.5.7 clickhouse-common-static=21.8.5.7`
+:::
+
+### From RPM Packages {#from-rpm-packages}
+
+It is recommended to use official pre-compiled `rpm` packages for CentOS, RedHat, and all other rpm-based Linux distributions.
+
+First, you need to add the official repository:
+
+``` bash
+sudo yum install -y yum-utils
+sudo yum-config-manager --add-repo https://packages.clickhouse.com/rpm/clickhouse.repo
+sudo yum install -y clickhouse-server clickhouse-client
+
+sudo /etc/init.d/clickhouse-server start
+clickhouse-client # or "clickhouse-client --password" if you set up a password.
+```
+
+<details markdown="1">
+
+<summary>Deprecated Method for installing rpm-packages</summary>
+
+``` bash
+sudo yum install yum-utils
+sudo rpm --import https://repo.clickhouse.com/CLICKHOUSE-KEY.GPG
+sudo yum-config-manager --add-repo https://repo.clickhouse.com/rpm/clickhouse.repo
+sudo yum install clickhouse-server clickhouse-client
+
+sudo /etc/init.d/clickhouse-server start
+clickhouse-client # or "clickhouse-client --password" if you set up a password.
+```
+
+</details>
+
+If you want to use the most recent version, replace `stable` with `testing` (this is recommended for your testing environments). `prestable` is sometimes also available.
+
+Then run these commands to install packages:
+
+``` bash
+sudo yum install clickhouse-server clickhouse-client
+```
+
+You can also download and install packages manually from [here](https://packages.clickhouse.com/rpm/stable).
+
+### From Tgz Archives {#from-tgz-archives}
+
+It is recommended to use official pre-compiled `tgz` archives for all Linux distributions, where installation of `deb` or `rpm` packages is not possible.
+
+The required version can be downloaded with `curl` or `wget` from repository https://packages.clickhouse.com/tgz/.
+After that downloaded archives should be unpacked and installed with installation scripts. Example for the latest stable version:
+
+``` bash
+LATEST_VERSION=$(curl -s https://packages.clickhouse.com/tgz/stable/ | \
+    grep -Eo '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+' | sort -V -r | head -n 1)
+export LATEST_VERSION
+curl -O "https://packages.clickhouse.com/tgz/stable/clickhouse-common-static-$LATEST_VERSION.tgz"
+curl -O "https://packages.clickhouse.com/tgz/stable/clickhouse-common-static-dbg-$LATEST_VERSION.tgz"
+curl -O "https://packages.clickhouse.com/tgz/stable/clickhouse-server-$LATEST_VERSION.tgz"
+curl -O "https://packages.clickhouse.com/tgz/stable/clickhouse-client-$LATEST_VERSION.tgz"
+
+tar -xzvf "clickhouse-common-static-$LATEST_VERSION.tgz"
+sudo "clickhouse-common-static-$LATEST_VERSION/install/doinst.sh"
+
+tar -xzvf "clickhouse-common-static-dbg-$LATEST_VERSION.tgz"
+sudo "clickhouse-common-static-dbg-$LATEST_VERSION/install/doinst.sh"
+
+tar -xzvf "clickhouse-server-$LATEST_VERSION.tgz"
+sudo "clickhouse-server-$LATEST_VERSION/install/doinst.sh"
+sudo /etc/init.d/clickhouse-server start
+
+tar -xzvf "clickhouse-client-$LATEST_VERSION.tgz"
+sudo "clickhouse-client-$LATEST_VERSION/install/doinst.sh"
+```
+
+<details markdown="1">
+
+<summary>Deprecated Method for installing tgz archives</summary>
+
+``` bash
+export LATEST_VERSION=$(curl -s https://repo.clickhouse.com/tgz/stable/ | \
+    grep -Eo '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+' | sort -V -r | head -n 1)
+curl -O https://repo.clickhouse.com/tgz/stable/clickhouse-common-static-$LATEST_VERSION.tgz
+curl -O https://repo.clickhouse.com/tgz/stable/clickhouse-common-static-dbg-$LATEST_VERSION.tgz
+curl -O https://repo.clickhouse.com/tgz/stable/clickhouse-server-$LATEST_VERSION.tgz
+curl -O https://repo.clickhouse.com/tgz/stable/clickhouse-client-$LATEST_VERSION.tgz
+
+tar -xzvf clickhouse-common-static-$LATEST_VERSION.tgz
+sudo clickhouse-common-static-$LATEST_VERSION/install/doinst.sh
+
+tar -xzvf clickhouse-common-static-dbg-$LATEST_VERSION.tgz
+sudo clickhouse-common-static-dbg-$LATEST_VERSION/install/doinst.sh
+
+tar -xzvf clickhouse-server-$LATEST_VERSION.tgz
+sudo clickhouse-server-$LATEST_VERSION/install/doinst.sh
+sudo /etc/init.d/clickhouse-server start
+
+tar -xzvf clickhouse-client-$LATEST_VERSION.tgz
+sudo clickhouse-client-$LATEST_VERSION/install/doinst.sh
+```
+</details>
+
+For production environments, it’s recommended to use the latest `stable`-version. You can find its number on GitHub page https://github.com/ClickHouse/ClickHouse/tags with postfix `-stable`.
+
+### From Docker Image {#from-docker-image}
+
+To run ClickHouse inside Docker follow the guide on [Docker Hub](https://hub.docker.com/r/clickhouse/clickhouse-server/). Those images use official `deb` packages inside.
+
+### Single Binary {#from-single-binary}
+
+You can install ClickHouse on Linux using a single portable binary from the latest commit of the `master` branch: [https://builds.clickhouse.com/master/amd64/clickhouse].
+
+``` bash
+curl -O 'https://builds.clickhouse.com/master/amd64/clickhouse' && chmod a+x clickhouse
+sudo ./clickhouse install
+```
+
+### From Precompiled Binaries for Non-Standard Environments {#from-binaries-non-linux}
+
+For non-Linux operating systems and for AArch64 CPU arhitecture, ClickHouse builds are provided as a cross-compiled binary from the latest commit of the `master` branch (with a few hours delay). 
+
+
+-   [MacOS x86_64](https://builds.clickhouse.com/master/macos/clickhouse)
+     ```bash
+     curl -O 'https://builds.clickhouse.com/master/macos/clickhouse' && chmod a+x ./clickhouse
+     ```
+-   [MacOS Aarch64 (Apple Silicon)](https://builds.clickhouse.com/master/macos-aarch64/clickhouse) 
+    ```bash
+    curl -O 'https://builds.clickhouse.com/master/macos-aarch64/clickhouse' && chmod a+x ./clickhouse
+    ```
+-   [FreeBSD x86_64](https://builds.clickhouse.com/master/freebsd/clickhouse) 
+    ```bash
+    curl -O 'https://builds.clickhouse.com/master/freebsd/clickhouse' && chmod a+x ./clickhouse
+    ```
+-   [Linux AArch64](https://builds.clickhouse.com/master/aarch64/clickhouse) 
+    ```bash
+    curl -O 'https://builds.clickhouse.com/master/aarch64/clickhouse' && chmod a+x ./clickhouse
+    ```
+
+Run `sudo ./clickhouse install` to install ClickHouse system-wide (also with needed configuration files, configuring users etc.). Then run `clickhouse start` commands to start the clickhouse-server and `clickhouse-client` to connect to it.
+
+Use the `clickhouse client` to connect to the server, or `clickhouse local` to process local data.
+
+### From Sources {#from-sources}
+
+To manually compile ClickHouse, follow the instructions for [Linux](./development/build.md) or [Mac OS X](./development/build-osx.md).
+
+You can compile packages and install them or use programs without installing packages. Also by building manually you can disable SSE 4.2 requirement or build for AArch64 CPUs.
+
+      Client: programs/clickhouse-client
+      Server: programs/clickhouse-server
+
+You’ll need to create a data and metadata folders and `chown` them for the desired user. Their paths can be changed in server config (src/programs/server/config.xml), by default they are:
+
+      /var/lib/clickhouse/data/default/
+      /var/lib/clickhouse/metadata/default/
+
+On Gentoo, you can just use `emerge clickhouse` to install ClickHouse from sources.
+
+## Launch {#launch}
+
+To start the server as a daemon, run:
+
+``` bash
+$ sudo clickhouse start
+```
+
+There are also another ways to run ClickHouse:
+
+``` bash
+$ sudo service clickhouse-server start
+```
+
+If you do not have `service` command, run as
+
+``` bash
+$ sudo /etc/init.d/clickhouse-server start
+```
+
+If you have `systemctl` command, run as
+
+``` bash
+$ sudo systemctl start clickhouse-server.service
+```
+
+See the logs in the `/var/log/clickhouse-server/` directory.
+
+If the server does not start, check the configurations in the file `/etc/clickhouse-server/config.xml`.
+
+You can also manually launch the server from the console:
+
+``` bash
+$ clickhouse-server --config-file=/etc/clickhouse-server/config.xml
+```
+
+In this case, the log will be printed to the console, which is convenient during development.
+If the configuration file is in the current directory, you do not need to specify the `--config-file` parameter. By default, it uses `./config.xml`.
+
+ClickHouse supports access restriction settings. They are located in the `users.xml` file (next to `config.xml`).
+By default, access is allowed from anywhere for the `default` user, without a password. See `user/default/networks`.
+For more information, see the section [“Configuration Files”](./operations/configuration-files.md).
+
+After launching server, you can use the command-line client to connect to it:
+
+``` bash
+$ clickhouse-client
+```
+
+By default, it connects to `localhost:9000` on behalf of the user `default` without a password. It can also be used to connect to a remote server using `--host` argument.
+
+The terminal must use UTF-8 encoding.
+For more information, see the section [“Command-line client”](./interfaces/cli.md).
+
+Example:
+
+```
+$ ./clickhouse-client
+ClickHouse client version 0.0.18749.
+Connecting to localhost:9000.
+Connected to ClickHouse server version 0.0.18749.
+
+:) SELECT 1
+
+SELECT 1
+
+┌─1─┐
+│ 1 │
+└───┘
+
+1 rows in set. Elapsed: 0.003 sec.
+
+:)
+```
+
+**Congratulations, the system works!**
+
+To continue experimenting, you can download one of the test data sets or go through [tutorial](./tutorial.md).
+
+[Original article](https://clickhouse.com/docs/en/getting_started/install/) <!--hide-->
diff --git a/docs/en/reference/getting-started/playground.md b/docs/en/reference/getting-started/playground.md
new file mode 100644
index 00000000000..ea7b2ccf2c5
--- /dev/null
+++ b/docs/en/reference/getting-started/playground.md
@@ -0,0 +1,46 @@
+---
+sidebar_label: Playground
+sidebar_position: 2
+keywords: [clickhouse, playground, getting, started, docs]
+description: The ClickHouse Playground allows people to experiment with ClickHouse by running queries instantly, without setting up their server or cluster.
+slug: /en/getting-started/playground
+---
+
+# ClickHouse Playground {#clickhouse-playground}
+
+[ClickHouse Playground](https://play.clickhouse.com/play?user=play) allows people to experiment with ClickHouse by running queries instantly, without setting up their server or cluster.
+Several example datasets are available in Playground.
+
+You can make queries to Playground using any HTTP client, for example [curl](https://curl.haxx.se) or [wget](https://www.gnu.org/software/wget/), or set up a connection using [JDBC](./interfaces/jdbc.md) or [ODBC](./interfaces/odbc.md) drivers. More information about software products that support ClickHouse is available [here](./interfaces/index.md).
+
+## Credentials {#credentials}
+
+| Parameter           | Value                              |
+|:--------------------|:-----------------------------------|
+| HTTPS endpoint      | `https://play.clickhouse.com:443/` |
+| Native TCP endpoint | `play.clickhouse.com:9440`         |
+| User                | `explorer` or `play`               |
+| Password            | (empty)                            |
+
+## Limitations {#limitations}
+
+The queries are executed as a read-only user. It implies some limitations:
+
+-   DDL queries are not allowed
+-   INSERT queries are not allowed
+
+The service also have quotas on its usage.
+
+## Examples {#examples}
+
+HTTPS endpoint example with `curl`:
+
+``` bash
+curl "https://play.clickhouse.com/?user=explorer" --data-binary "SELECT 'Play ClickHouse'"
+```
+
+TCP endpoint example with [CLI](./interfaces/cli.md):
+
+``` bash
+clickhouse client --secure --host play.clickhouse.com --user explorer
+```
diff --git a/docs/en/reference/images/column-oriented.gif b/docs/en/reference/images/column-oriented.gif
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diff --git a/docs/en/reference/interfaces/cli.md b/docs/en/reference/interfaces/cli.md
new file mode 100644
index 00000000000..9ef1cea280a
--- /dev/null
+++ b/docs/en/reference/interfaces/cli.md
@@ -0,0 +1,181 @@
+---
+sidebar_position: 17
+sidebar_label: Command-Line Client
+---
+
+# Command-line Client {#command-line-client}
+
+ClickHouse provides a native command-line client: `clickhouse-client`. The client supports command-line options and configuration files. For more information, see [Configuring](#interfaces_cli_configuration).
+
+[Install](../../quick-start.mdx) it from the `clickhouse-client` package and run it with the command `clickhouse-client`.
+
+``` bash
+$ clickhouse-client
+ClickHouse client version 20.13.1.5273 (official build).
+Connecting to localhost:9000 as user default.
+Connected to ClickHouse server version 20.13.1 revision 54442.
+
+:)
+```
+
+Different client and server versions are compatible with one another, but some features may not be available in older clients. We recommend using the same version of the client as the server app. When you try to use a client of the older version, then the server, `clickhouse-client` displays the message:
+
+      ClickHouse client version is older than ClickHouse server. It may lack support for new features.
+
+## Usage {#cli_usage}
+
+The client can be used in interactive and non-interactive (batch) mode. To use batch mode, specify the ‘query’ parameter, or send data to ‘stdin’ (it verifies that ‘stdin’ is not a terminal), or both. Similar to the HTTP interface, when using the ‘query’ parameter and sending data to ‘stdin’, the request is a concatenation of the ‘query’ parameter, a line feed, and the data in ‘stdin’. This is convenient for large INSERT queries.
+
+Example of using the client to insert data:
+
+``` bash
+$ echo -ne "1, 'some text', '2016-08-14 00:00:00'\n2, 'some more text', '2016-08-14 00:00:01'" | clickhouse-client --database=test --query="INSERT INTO test FORMAT CSV";
+
+$ cat <<_EOF | clickhouse-client --database=test --query="INSERT INTO test FORMAT CSV";
+3, 'some text', '2016-08-14 00:00:00'
+4, 'some more text', '2016-08-14 00:00:01'
+_EOF
+
+$ cat file.csv | clickhouse-client --database=test --query="INSERT INTO test FORMAT CSV";
+```
+
+In batch mode, the default data format is TabSeparated. You can set the format in the FORMAT clause of the query.
+
+By default, you can only process a single query in batch mode. To make multiple queries from a “script,” use the `--multiquery` parameter. This works for all queries except INSERT. Query results are output consecutively without additional separators. Similarly, to process a large number of queries, you can run ‘clickhouse-client’ for each query. Note that it may take tens of milliseconds to launch the ‘clickhouse-client’ program.
+
+In interactive mode, you get a command line where you can enter queries.
+
+If ‘multiline’ is not specified (the default): To run the query, press Enter. The semicolon is not necessary at the end of the query. To enter a multiline query, enter a backslash `\` before the line feed. After you press Enter, you will be asked to enter the next line of the query.
+
+If multiline is specified: To run a query, end it with a semicolon and press Enter. If the semicolon was omitted at the end of the entered line, you will be asked to enter the next line of the query.
+
+Only a single query is run, so everything after the semicolon is ignored.
+
+You can specify `\G` instead of or after the semicolon. This indicates Vertical format. In this format, each value is printed on a separate line, which is convenient for wide tables. This unusual feature was added for compatibility with the MySQL CLI.
+
+The command line is based on ‘replxx’ (similar to ‘readline’). In other words, it uses the familiar keyboard shortcuts and keeps a history. The history is written to `~/.clickhouse-client-history`.
+
+By default, the format used is PrettyCompact. You can change the format in the FORMAT clause of the query, or by specifying `\G` at the end of the query, using the `--format` or `--vertical` argument in the command line, or using the client configuration file.
+
+To exit the client, press Ctrl+D, or enter one of the following instead of a query: “exit”, “quit”, “logout”, “exit;”, “quit;”, “logout;”, “q”, “Q”, “:q”
+
+When processing a query, the client shows:
+
+1.  Progress, which is updated no more than 10 times per second (by default). For quick queries, the progress might not have time to be displayed.
+2.  The formatted query after parsing, for debugging.
+3.  The result in the specified format.
+4.  The number of lines in the result, the time passed, and the average speed of query processing.
+
+You can cancel a long query by pressing Ctrl+C. However, you will still need to wait for a little for the server to abort the request. It is not possible to cancel a query at certain stages. If you do not wait and press Ctrl+C a second time, the client will exit.
+
+The command-line client allows passing external data (external temporary tables) for querying. For more information, see the section “External data for query processing”.
+
+### Queries with Parameters {#cli-queries-with-parameters}
+
+You can create a query with parameters and pass values to them from client application. This allows to avoid formatting query with specific dynamic values on client side. For example:
+
+``` bash
+$ clickhouse-client --param_parName="[1, 2]"  -q "SELECT * FROM table WHERE a = {parName:Array(UInt16)}"
+```
+
+#### Query Syntax {#cli-queries-with-parameters-syntax}
+
+Format a query as usual, then place the values that you want to pass from the app parameters to the query in braces in the following format:
+
+``` sql
+{<name>:<data type>}
+```
+
+-   `name` — Placeholder identifier. In the console client it should be used in app parameters as `--param_<name> = value`.
+-   `data type` — [Data type](../sql-reference/data-types/index.md) of the app parameter value. For example, a data structure like `(integer, ('string', integer))` can have the `Tuple(UInt8, Tuple(String, UInt8))` data type (you can also use another [integer](../sql-reference/data-types/int-uint.md) types). It's also possible to pass table, database, column names as a parameter, in that case you would need to use `Identifier` as a data type.
+
+#### Example {#example}
+
+``` bash
+$ clickhouse-client --param_tuple_in_tuple="(10, ('dt', 10))" -q "SELECT * FROM table WHERE val = {tuple_in_tuple:Tuple(UInt8, Tuple(String, UInt8))}"
+$ clickhouse-client --param_tbl="numbers" --param_db="system" --param_col="number" --query "SELECT {col:Identifier} FROM {db:Identifier}.{tbl:Identifier} LIMIT 10"
+```
+
+## Configuring {#interfaces_cli_configuration}
+
+You can pass parameters to `clickhouse-client` (all parameters have a default value) using:
+
+-   From the Command Line
+
+    Command-line options override the default values and settings in configuration files.
+
+-   Configuration files.
+
+    Settings in the configuration files override the default values.
+
+### Command Line Options {#command-line-options}
+
+-   `--host, -h` – The server name, ‘localhost’ by default. You can use either the name or the IPv4 or IPv6 address.
+-   `--port` – The port to connect to. Default value: 9000. Note that the HTTP interface and the native interface use different ports.
+-   `--user, -u` – The username. Default value: default.
+-   `--password` – The password. Default value: empty string.
+-   `--query, -q` – The query to process when using non-interactive mode. You must specify either `query` or `queries-file` option.
+-   `--queries-file, -qf` – file path with queries to execute. You must specify either `query` or `queries-file` option.
+-   `--database, -d` – Select the current default database. Default value: the current database from the server settings (‘default’ by default).
+-   `--multiline, -m` – If specified, allow multiline queries (do not send the query on Enter).
+-   `--multiquery, -n` – If specified, allow processing multiple queries separated by semicolons.
+-   `--format, -f` – Use the specified default format to output the result.
+-   `--vertical, -E` – If specified, use the [Vertical format](../interfaces/formats.md#vertical) by default to output the result. This is the same as `–format=Vertical`. In this format, each value is printed on a separate line, which is helpful when displaying wide tables.
+-   `--time, -t` – If specified, print the query execution time to ‘stderr’ in non-interactive mode.
+-   `--stacktrace` – If specified, also print the stack trace if an exception occurs.
+-   `--config-file` – The name of the configuration file.
+-   `--secure` – If specified, will connect to server over secure connection.
+-   `--history_file` — Path to a file containing command history.
+-   `--param_<name>` — Value for a [query with parameters](#cli-queries-with-parameters).
+-   `--hardware-utilization` — Print hardware utilization information in progress bar.
+-   `--print-profile-events` – Print `ProfileEvents` packets.
+-   `--profile-events-delay-ms` – Delay between printing `ProfileEvents` packets (-1 - print only totals, 0 - print every single packet).
+
+Since version 20.5, `clickhouse-client` has automatic syntax highlighting (always enabled).
+
+### Configuration Files {#configuration_files}
+
+`clickhouse-client` uses the first existing file of the following:
+
+-   Defined in the `--config-file` parameter.
+-   `./clickhouse-client.xml`
+-   `~/.clickhouse-client/config.xml`
+-   `/etc/clickhouse-client/config.xml`
+
+Example of a config file:
+
+```xml
+<config>
+    <user>username</user>
+    <password>password</password>
+    <secure>False</secure>
+</config>
+```
+
+### Query ID Format {#query-id-format}
+
+In interactive mode `clickhouse-client` shows query ID for every query. By default, the ID is formatted like this:
+
+```sql
+Query id: 927f137d-00f1-4175-8914-0dd066365e96
+```
+
+A custom format may be specified in a configuration file inside a `query_id_formats` tag. `{query_id}` placeholder in the format string is replaced with the ID of a query. Several format strings are allowed inside the tag.
+This feature can be used to generate URLs to facilitate profiling of queries.
+
+**Example**
+
+```xml
+<config>
+  <query_id_formats>
+    <speedscope>http://speedscope-host/#profileURL=qp%3Fid%3D{query_id}</speedscope>
+  </query_id_formats>
+</config>
+```
+
+If the configuration above is applied, the ID of a query is shown in the following format:
+
+``` text
+speedscope:http://speedscope-host/#profileURL=qp%3Fid%3Dc8ecc783-e753-4b38-97f1-42cddfb98b7d
+```
+
diff --git a/docs/en/reference/interfaces/cpp.md b/docs/en/reference/interfaces/cpp.md
new file mode 100644
index 00000000000..a7b4188799e
--- /dev/null
+++ b/docs/en/reference/interfaces/cpp.md
@@ -0,0 +1,10 @@
+---
+sidebar_position: 24
+sidebar_label: C++ Client Library
+---
+
+# C++ Client Library {#c-client-library}
+
+See README at [clickhouse-cpp](https://github.com/ClickHouse/clickhouse-cpp) repository.
+
+[Original article](https://clickhouse.com/docs/en/interfaces/cpp/) <!--hide-->
diff --git a/docs/en/reference/interfaces/formats.md b/docs/en/reference/interfaces/formats.md
new file mode 100644
index 00000000000..801b7c1a14f
--- /dev/null
+++ b/docs/en/reference/interfaces/formats.md
@@ -0,0 +1,1707 @@
+---
+sidebar_position: 21
+sidebar_label: Input and Output Formats
+---
+
+# Formats for Input and Output Data {#formats}
+
+ClickHouse can accept and return data in various formats. A format supported for input can be used to parse the data provided to `INSERT`s, to perform `SELECT`s from a file-backed table such as File, URL or HDFS, or to read an external dictionary. A format supported for output can be used to arrange the
+results of a `SELECT`, and to perform `INSERT`s into a file-backed table.
+
+The supported formats are:
+
+| Format                                                                                  | Input | Output |
+|-----------------------------------------------------------------------------------------|-------|--------|
+| [TabSeparated](#tabseparated)                                                           | ✔     | ✔      |
+| [TabSeparatedRaw](#tabseparatedraw)                                                     | ✔     | ✔      |
+| [TabSeparatedWithNames](#tabseparatedwithnames)                                         | ✔     | ✔      |
+| [TabSeparatedWithNamesAndTypes](#tabseparatedwithnamesandtypes)                         | ✔     | ✔      |
+| [TabSeparatedRawWithNames](#tabseparatedrawwithnames)                                                     | ✔     | ✔      |
+| [TabSeparatedRawWithNamesAndTypes](#tabseparatedrawwithnamesandtypes)                                                     | ✔     | ✔      |
+| [Template](#format-template)                                                            | ✔     | ✔      |
+| [TemplateIgnoreSpaces](#templateignorespaces)                                           | ✔     | ✗      |
+| [CSV](#csv)                                                                             | ✔     | ✔      |
+| [CSVWithNames](#csvwithnames)                                                           | ✔     | ✔      |
+| [CSVWithNamesAndTypes](#csvwithnamesandtypes)                                                           | ✔     | ✔      |
+| [CustomSeparated](#format-customseparated)                                              | ✔     | ✔      |
+| [CustomSeparatedWithNames](#customseparatedwithnames)                                   | ✔     | ✔      |
+| [CustomSeparatedWithNamesAndTypes](#customseparatedwithnamesandtypes)                   | ✔     | ✔      |
+| [Values](#data-format-values)                                                           | ✔     | ✔      |
+| [Vertical](#vertical)                                                                   | ✗     | ✔      |
+| [JSON](#json)                                                                           | ✗     | ✔      |
+| [JSONAsString](#jsonasstring)                                                           | ✔     | ✗      |
+| [JSONStrings](#jsonstrings)                                                               | ✗     | ✔      |
+| [JSONCompact](#jsoncompact)                                                             | ✗     | ✔      |
+| [JSONCompactStrings](#jsoncompactstrings)                                                 | ✗     | ✔      |
+| [JSONEachRow](#jsoneachrow)                                                             | ✔     | ✔      |
+| [JSONEachRowWithProgress](#jsoneachrowwithprogress)                                     | ✗     | ✔      |
+| [JSONStringsEachRow](#jsonstringseachrow)                                               | ✔     | ✔      |
+| [JSONStringsEachRowWithProgress](#jsonstringseachrowwithprogress)                       | ✗     | ✔      |
+| [JSONCompactEachRow](#jsoncompacteachrow)                                               | ✔     | ✔      |
+| [JSONCompactEachRowWithNames](#jsoncompacteachrowwithnames)             | ✔     | ✔      |
+| [JSONCompactEachRowWithNamesAndTypes](#jsoncompacteachrowwithnamesandtypes)             | ✔     | ✔      |
+| [JSONCompactStringsEachRow](#jsoncompactstringseachrow)                                   | ✔     | ✔      |
+| [JSONCompactStringsEachRowWithNames](#jsoncompactstringseachrowwithnames) | ✔     | ✔      |
+| [JSONCompactStringsEachRowWithNamesAndTypes](#jsoncompactstringseachrowwithnamesandtypes) | ✔     | ✔      |
+| [TSKV](#tskv)                                                                           | ✔     | ✔      |
+| [Pretty](#pretty)                                                                       | ✗     | ✔      |
+| [PrettyCompact](#prettycompact)                                                         | ✗     | ✔      |
+| [PrettyCompactMonoBlock](#prettycompactmonoblock)                                       | ✗     | ✔      |
+| [PrettyNoEscapes](#prettynoescapes)                                                     | ✗     | ✔      |
+| [PrettySpace](#prettyspace)                                                             | ✗     | ✔      |
+| [Protobuf](#protobuf)                                                                   | ✔     | ✔      |
+| [ProtobufSingle](#protobufsingle)                                                       | ✔     | ✔      |
+| [Avro](#data-format-avro)                                                               | ✔     | ✔      |
+| [AvroConfluent](#data-format-avro-confluent)                                            | ✔     | ✗      |
+| [Parquet](#data-format-parquet)                                                         | ✔     | ✔      |
+| [Arrow](#data-format-arrow)                                                             | ✔     | ✔      |
+| [ArrowStream](#data-format-arrow-stream)                                                | ✔     | ✔      |
+| [ORC](#data-format-orc)                                                                 | ✔     | ✔      |
+| [RowBinary](#rowbinary)                                                                 | ✔     | ✔      |
+| [RowBinaryWithNames](#rowbinarywithnamesandtypes)                               | ✔     | ✔      |
+| [RowBinaryWithNamesAndTypes](#rowbinarywithnamesandtypes)                               | ✔     | ✔      |
+| [Native](#native)                                                                       | ✔     | ✔      |
+| [Null](#null)                                                                           | ✗     | ✔      |
+| [XML](#xml)                                                                             | ✗     | ✔      |
+| [CapnProto](#capnproto)                                                                 | ✔     | ✔      |
+| [LineAsString](#lineasstring)                                                           | ✔     | ✗      |
+| [Regexp](#data-format-regexp)                                                           | ✔     | ✗      |
+| [RawBLOB](#rawblob)                                                                     | ✔     | ✔      |
+| [MsgPack](#msgpack)                                                                     | ✔     | ✔      |
+
+You can control some format processing parameters with the ClickHouse settings. For more information read the [Settings](../operations/settings/settings.md) section.
+
+## TabSeparated {#tabseparated}
+
+In TabSeparated format, data is written by row. Each row contains values separated by tabs. Each value is followed by a tab, except the last value in the row, which is followed by a line feed. Strictly Unix line feeds are assumed everywhere. The last row also must contain a line feed at the end. Values are written in text format, without enclosing quotation marks, and with special characters escaped.
+
+This format is also available under the name `TSV`.
+
+The `TabSeparated` format is convenient for processing data using custom programs and scripts. It is used by default in the HTTP interface, and in the command-line client’s batch mode. This format also allows transferring data between different DBMSs. For example, you can get a dump from MySQL and upload it to ClickHouse, or vice versa.
+
+The `TabSeparated` format supports outputting total values (when using WITH TOTALS) and extreme values (when ‘extremes’ is set to 1). In these cases, the total values and extremes are output after the main data. The main result, total values, and extremes are separated from each other by an empty line. Example:
+
+``` sql
+SELECT EventDate, count() AS c FROM test.hits GROUP BY EventDate WITH TOTALS ORDER BY EventDate FORMAT TabSeparated
+```
+
+``` text
+2014-03-17      1406958
+2014-03-18      1383658
+2014-03-19      1405797
+2014-03-20      1353623
+2014-03-21      1245779
+2014-03-22      1031592
+2014-03-23      1046491
+
+1970-01-01      8873898
+
+2014-03-17      1031592
+2014-03-23      1406958
+```
+
+### Data Formatting {#data-formatting}
+
+Integer numbers are written in decimal form. Numbers can contain an extra “+” character at the beginning (ignored when parsing, and not recorded when formatting). Non-negative numbers can’t contain the negative sign. When reading, it is allowed to parse an empty string as a zero, or (for signed types) a string consisting of just a minus sign as a zero. Numbers that do not fit into the corresponding data type may be parsed as a different number, without an error message.
+
+Floating-point numbers are written in decimal form. The dot is used as the decimal separator. Exponential entries are supported, as are ‘inf’, ‘+inf’, ‘-inf’, and ‘nan’. An entry of floating-point numbers may begin or end with a decimal point.
+During formatting, accuracy may be lost on floating-point numbers.
+During parsing, it is not strictly required to read the nearest machine-representable number.
+
+Dates are written in YYYY-MM-DD format and parsed in the same format, but with any characters as separators.
+Dates with times are written in the format `YYYY-MM-DD hh:mm:ss` and parsed in the same format, but with any characters as separators.
+This all occurs in the system time zone at the time the client or server starts (depending on which of them formats data). For dates with times, daylight saving time is not specified. So if a dump has times during daylight saving time, the dump does not unequivocally match the data, and parsing will select one of the two times.
+During a read operation, incorrect dates and dates with times can be parsed with natural overflow or as null dates and times, without an error message.
+
+As an exception, parsing dates with times is also supported in Unix timestamp format, if it consists of exactly 10 decimal digits. The result is not time zone-dependent. The formats YYYY-MM-DD hh:mm:ss and NNNNNNNNNN are differentiated automatically.
+
+Strings are output with backslash-escaped special characters. The following escape sequences are used for output: `\b`, `\f`, `\r`, `\n`, `\t`, `\0`, `\'`, `\\`. Parsing also supports the sequences `\a`, `\v`, and `\xHH` (hex escape sequences) and any `\c` sequences, where `c` is any character (these sequences are converted to `c`). Thus, reading data supports formats where a line feed can be written as `\n` or `\`, or as a line feed. For example, the string `Hello world` with a line feed between the words instead of space can be parsed in any of the following variations:
+
+``` text
+Hello\nworld
+
+Hello\
+world
+```
+
+The second variant is supported because MySQL uses it when writing tab-separated dumps.
+
+The minimum set of characters that you need to escape when passing data in TabSeparated format: tab, line feed (LF) and backslash.
+
+Only a small set of symbols are escaped. You can easily stumble onto a string value that your terminal will ruin in output.
+
+Arrays are written as a list of comma-separated values in square brackets. Number items in the array are formatted as normally. `Date` and `DateTime` types are written in single quotes. Strings are written in single quotes with the same escaping rules as above.
+
+[NULL](../sql-reference/syntax.md) is formatted according to setting [format_tsv_null_representation](../operations/settings/settings.md#settings-format_tsv_null_representation) (default value is `\N`).
+
+
+If setting [input_format_tsv_empty_as_default](../operations/settings/settings.md#settings-input_format_tsv_empty_as_default) is enabled,
+empty input fields are replaced with default values. For complex default expressions [input_format_defaults_for_omitted_fields](../operations/settings/settings.md#settings-input_format_defaults_for_omitted_fields) must be enabled too.
+
+Each element of [Nested](../sql-reference/data-types/nested-data-structures/nested.md) structures is represented as array.
+
+In input data, ENUM values can be represented as names or as ids. First, we try to match the input value to the ENUM name. If we fail and the input value is a number, we try to match this number to ENUM id.
+If input data contains only ENUM ids, it's recommended to enable the setting [input_format_tsv_enum_as_number](../operations/settings/settings.md#settings-input_format_tsv_enum_as_number) to optimize ENUM parsing.
+
+For example:
+
+``` sql
+CREATE TABLE nestedt
+(
+    `id` UInt8,
+    `aux` Nested(
+        a UInt8,
+        b String
+    )
+)
+ENGINE = TinyLog
+```
+
+``` sql
+INSERT INTO nestedt Values ( 1, [1], ['a'])
+```
+
+``` sql
+SELECT * FROM nestedt FORMAT TSV
+```
+
+``` text
+1  [1]    ['a']
+```
+
+## TabSeparatedRaw {#tabseparatedraw}
+
+Differs from `TabSeparated` format in that the rows are written without escaping.
+When parsing with this format, tabs or linefeeds are not allowed in each field.
+
+This format is also available under the name `TSVRaw`.
+
+## TabSeparatedWithNames {#tabseparatedwithnames}
+
+Differs from the `TabSeparated` format in that the column names are written in the first row.
+
+During parsing, the first row is expected to contain the column names. You can use column names to determine their position and to check their correctness.
+
+If setting [input_format_with_names_use_header](../operations/settings/settings.md#settings-input_format_with_names_use_header) is set to 1,
+the columns from input data will be mapped to the columns from the table by their names, columns with unknown names will be skipped if setting [input_format_skip_unknown_fields](../operations/settings/settings.md#settings-input_format_skip_unknown_fields) is set to 1.
+Otherwise, the first row will be skipped.
+
+This format is also available under the name `TSVWithNames`.
+
+## TabSeparatedWithNamesAndTypes {#tabseparatedwithnamesandtypes}
+
+Differs from the `TabSeparated` format in that the column names are written to the first row, while the column types are in the second row.
+The first row with names is processed the same way as in `TabSeparatedWithNames` format.
+If setting [input_format_with_types_use_header](../operations/settings/settings.md#settings-input_format_with_types_use_header) is set to 1,
+the types from input data will be compared with the types of the corresponding columns from the table. Otherwise, the second row will be skipped. 
+
+This format is also available under the name `TSVWithNamesAndTypes`.
+
+## TabSeparatedRawWithNames {#tabseparatedrawwithnames}
+
+Differs from `TabSeparatedWithNames` format in that the rows are written without escaping.
+When parsing with this format, tabs or linefeeds are not allowed in each field.
+
+This format is also available under the name `TSVRawWithNames`.
+
+## TabSeparatedRawWithNamesAndTypes {#tabseparatedrawwithnamesandtypes}
+
+Differs from `TabSeparatedWithNamesAndTypes` format in that the rows are written without escaping.
+When parsing with this format, tabs or linefeeds are not allowed in each field.
+
+This format is also available under the name `TSVRawWithNamesAndNames`.
+
+## Template {#format-template}
+
+This format allows specifying a custom format string with placeholders for values with a specified escaping rule.
+
+It uses settings `format_template_resultset`, `format_template_row`, `format_template_rows_between_delimiter` and some settings of other formats (e.g. `output_format_json_quote_64bit_integers` when using `JSON` escaping, see further)
+
+Setting `format_template_row` specifies path to file, which contains format string for rows with the following syntax:
+
+`delimiter_1${column_1:serializeAs_1}delimiter_2${column_2:serializeAs_2} ... delimiter_N`,
+
+where `delimiter_i` is a delimiter between values (`$` symbol can be escaped as `$$`),
+`column_i` is a name or index of a column whose values are to be selected or inserted (if empty, then column will be skipped),
+`serializeAs_i` is an escaping rule for the column values. The following escaping rules are supported:
+
+-   `CSV`, `JSON`, `XML` (similarly to the formats of the same names)
+-   `Escaped` (similarly to `TSV`)
+-   `Quoted` (similarly to `Values`)
+-   `Raw` (without escaping, similarly to `TSVRaw`)
+-   `None` (no escaping rule, see further)
+
+If an escaping rule is omitted, then `None` will be used. `XML` is suitable only for output.
+
+So, for the following format string:
+
+      `Search phrase: ${SearchPhrase:Quoted}, count: ${c:Escaped}, ad price: $$${price:JSON};`
+
+the values of `SearchPhrase`, `c` and `price` columns, which are escaped as `Quoted`, `Escaped` and `JSON` will be printed (for select) or will be expected (for insert) between `Search phrase:`, `, count:`, `, ad price: $` and `;` delimiters respectively. For example:
+
+`Search phrase: 'bathroom interior design', count: 2166, ad price: $3;`
+
+The `format_template_rows_between_delimiter` setting specifies delimiter between rows, which is printed (or expected) after every row except the last one (`\n` by default)
+
+Setting `format_template_resultset` specifies the path to file, which contains a format string for resultset. Format string for resultset has the same syntax as a format string for row and allows to specify a prefix, a suffix and a way to print some additional information. It contains the following placeholders instead of column names:
+
+-   `data` is the rows with data in `format_template_row` format, separated by `format_template_rows_between_delimiter`. This placeholder must be the first placeholder in the format string.
+-   `totals` is the row with total values in `format_template_row` format (when using WITH TOTALS)
+-   `min` is the row with minimum values in `format_template_row` format (when extremes are set to 1)
+-   `max` is the row with maximum values in `format_template_row` format (when extremes are set to 1)
+-   `rows` is the total number of output rows
+-   `rows_before_limit` is the minimal number of rows there would have been without LIMIT. Output only if the query contains LIMIT. If the query contains GROUP BY, rows_before_limit_at_least is the exact number of rows there would have been without a LIMIT.
+-   `time` is the request execution time in seconds
+-   `rows_read` is the number of rows has been read
+-   `bytes_read` is the number of bytes (uncompressed) has been read
+
+The placeholders `data`, `totals`, `min` and `max` must not have escaping rule specified (or `None` must be specified explicitly). The remaining placeholders may have any escaping rule specified.
+If the `format_template_resultset` setting is an empty string, `${data}` is used as default value.
+For insert queries format allows skipping some columns or some fields if prefix or suffix (see example).
+
+Select example:
+
+``` sql
+SELECT SearchPhrase, count() AS c FROM test.hits GROUP BY SearchPhrase ORDER BY c DESC LIMIT 5 FORMAT Template SETTINGS
+format_template_resultset = '/some/path/resultset.format', format_template_row = '/some/path/row.format', format_template_rows_between_delimiter = '\n    '
+```
+
+`/some/path/resultset.format`:
+
+``` text
+<!DOCTYPE HTML>
+<html> <head> <title>Search phrases</title> </head>
+ <body>
+  <table border="1"> <caption>Search phrases</caption>
+    <tr> <th>Search phrase</th> <th>Count</th> </tr>
+    ${data}
+  </table>
+  <table border="1"> <caption>Max</caption>
+    ${max}
+  </table>
+  <b>Processed ${rows_read:XML} rows in ${time:XML} sec</b>
+ </body>
+</html>
+```
+
+`/some/path/row.format`:
+
+``` text
+<tr> <td>${0:XML}</td> <td>${1:XML}</td> </tr>
+```
+
+Result:
+
+``` html
+<!DOCTYPE HTML>
+<html> <head> <title>Search phrases</title> </head>
+ <body>
+  <table border="1"> <caption>Search phrases</caption>
+    <tr> <th>Search phrase</th> <th>Count</th> </tr>
+    <tr> <td></td> <td>8267016</td> </tr>
+    <tr> <td>bathroom interior design</td> <td>2166</td> </tr>
+    <tr> <td>clickhouse</td> <td>1655</td> </tr>
+    <tr> <td>spring 2014 fashion</td> <td>1549</td> </tr>
+    <tr> <td>freeform photos</td> <td>1480</td> </tr>
+  </table>
+  <table border="1"> <caption>Max</caption>
+    <tr> <td></td> <td>8873898</td> </tr>
+  </table>
+  <b>Processed 3095973 rows in 0.1569913 sec</b>
+ </body>
+</html>
+```
+
+Insert example:
+
+``` text
+Some header
+Page views: 5, User id: 4324182021466249494, Useless field: hello, Duration: 146, Sign: -1
+Page views: 6, User id: 4324182021466249494, Useless field: world, Duration: 185, Sign: 1
+Total rows: 2
+```
+
+``` sql
+INSERT INTO UserActivity FORMAT Template SETTINGS
+format_template_resultset = '/some/path/resultset.format', format_template_row = '/some/path/row.format'
+```
+
+`/some/path/resultset.format`:
+
+``` text
+Some header\n${data}\nTotal rows: ${:CSV}\n
+```
+
+`/some/path/row.format`:
+
+``` text
+Page views: ${PageViews:CSV}, User id: ${UserID:CSV}, Useless field: ${:CSV}, Duration: ${Duration:CSV}, Sign: ${Sign:CSV}
+```
+
+`PageViews`, `UserID`, `Duration` and `Sign` inside placeholders are names of columns in the table. Values after `Useless field` in rows and after `\nTotal rows:` in suffix will be ignored.
+All delimiters in the input data must be strictly equal to delimiters in specified format strings.
+
+## TemplateIgnoreSpaces {#templateignorespaces}
+
+This format is suitable only for input.
+Similar to `Template`, but skips whitespace characters between delimiters and values in the input stream. However, if format strings contain whitespace characters, these characters will be expected in the input stream. Also allows to specify empty placeholders (`${}` or `${:None}`) to split some delimiter into separate parts to ignore spaces between them. Such placeholders are used only for skipping whitespace characters.
+It’s possible to read `JSON` using this format, if values of columns have the same order in all rows. For example, the following request can be used for inserting data from output example of format [JSON](#json):
+
+``` sql
+INSERT INTO table_name FORMAT TemplateIgnoreSpaces SETTINGS
+format_template_resultset = '/some/path/resultset.format', format_template_row = '/some/path/row.format', format_template_rows_between_delimiter = ','
+```
+
+`/some/path/resultset.format`:
+
+``` text
+{${}"meta"${}:${:JSON},${}"data"${}:${}[${data}]${},${}"totals"${}:${:JSON},${}"extremes"${}:${:JSON},${}"rows"${}:${:JSON},${}"rows_before_limit_at_least"${}:${:JSON}${}}
+```
+
+`/some/path/row.format`:
+
+``` text
+{${}"SearchPhrase"${}:${}${phrase:JSON}${},${}"c"${}:${}${cnt:JSON}${}}
+```
+
+## TSKV {#tskv}
+
+Similar to TabSeparated, but outputs a value in name=value format. Names are escaped the same way as in TabSeparated format, and the = symbol is also escaped.
+
+``` text
+SearchPhrase=   count()=8267016
+SearchPhrase=bathroom interior design    count()=2166
+SearchPhrase=clickhouse     count()=1655
+SearchPhrase=2014 spring fashion    count()=1549
+SearchPhrase=freeform photos       count()=1480
+SearchPhrase=angelina jolie    count()=1245
+SearchPhrase=omsk       count()=1112
+SearchPhrase=photos of dog breeds    count()=1091
+SearchPhrase=curtain designs        count()=1064
+SearchPhrase=baku       count()=1000
+```
+
+[NULL](../sql-reference/syntax.md) is formatted as `\N`.
+
+``` sql
+SELECT * FROM t_null FORMAT TSKV
+```
+
+``` text
+x=1    y=\N
+```
+
+When there is a large number of small columns, this format is ineffective, and there is generally no reason to use it. Nevertheless, it is no worse than JSONEachRow in terms of efficiency.
+
+Both data output and parsing are supported in this format. For parsing, any order is supported for the values of different columns. It is acceptable for some values to be omitted – they are treated as equal to their default values. In this case, zeros and blank rows are used as default values. Complex values that could be specified in the table are not supported as defaults.
+
+Parsing allows the presence of the additional field `tskv` without the equal sign or a value. This field is ignored.
+
+## CSV {#csv}
+
+Comma Separated Values format ([RFC](https://tools.ietf.org/html/rfc4180)).
+
+When formatting, rows are enclosed in double-quotes. A double quote inside a string is output as two double quotes in a row. There are no other rules for escaping characters. Date and date-time are enclosed in double-quotes. Numbers are output without quotes. Values are separated by a delimiter character, which is `,` by default. The delimiter character is defined in the setting [format_csv_delimiter](../operations/settings/settings.md#settings-format_csv_delimiter). Rows are separated using the Unix line feed (LF). Arrays are serialized in CSV as follows: first, the array is serialized to a string as in TabSeparated format, and then the resulting string is output to CSV in double-quotes. Tuples in CSV format are serialized as separate columns (that is, their nesting in the tuple is lost).
+
+``` bash
+$ clickhouse-client --format_csv_delimiter="|" --query="INSERT INTO test.csv FORMAT CSV" < data.csv
+```
+
+\*By default, the delimiter is `,`. See the [format_csv_delimiter](../operations/settings/settings.md#settings-format_csv_delimiter) setting for more information.
+
+When parsing, all values can be parsed either with or without quotes. Both double and single quotes are supported. Rows can also be arranged without quotes. In this case, they are parsed up to the delimiter character or line feed (CR or LF). In violation of the RFC, when parsing rows without quotes, the leading and trailing spaces and tabs are ignored. For the line feed, Unix (LF), Windows (CR LF) and Mac OS Classic (CR LF) types are all supported.
+
+If setting [input_format_csv_empty_as_default](../operations/settings/settings.md#settings-input_format_csv_empty_as_default) is enabled,
+empty unquoted input values are replaced with default values. For complex default expressions [input_format_defaults_for_omitted_fields](../operations/settings/settings.md#settings-input_format_defaults_for_omitted_fields) must be enabled too.
+
+`NULL` is formatted according to setting [format_csv_null_representation](../operations/settings/settings.md#settings-format_csv_null_representation) (default value is `\N`).
+
+In input data, ENUM values can be represented as names or as ids. First, we try to match the input value to the ENUM name. If we fail and the input value is a number, we try to match this number to ENUM id.
+If input data contains only ENUM ids, it's recommended to enable the setting [input_format_csv_enum_as_number](../operations/settings/settings.md#settings-input_format_csv_enum_as_number) to optimize ENUM parsing.
+
+The CSV format supports the output of totals and extremes the same way as `TabSeparated`.
+
+## CSVWithNames {#csvwithnames}
+
+Also prints the header row with column names, similar to [TabSeparatedWithNames](#tabseparatedwithnames).
+
+## CSVWithNamesAndTypes {#csvwithnamesandtypes}
+
+Also prints two header rows with column names and types, similar to [TabSeparatedWithNamesAndTypes](#tabseparatedwithnamesandtypes).
+
+## CustomSeparated {#format-customseparated}
+
+Similar to [Template](#format-template), but it prints or reads all names and types of columns and uses escaping rule from [format_custom_escaping_rule](../operations/settings/settings.md#format-custom-escaping-rule) setting and delimiters from [format_custom_field_delimiter](../operations/settings/settings.md#format-custom-field-delimiter), [format_custom_row_before_delimiter](../operations/settings/settings.md#format-custom-row-before-delimiter), [format_custom_row_after_delimiter](../operations/settings/settings.md#format-custom-row-after-delimiter), [format_custom_row_between_delimiter](../operations/settings/settings.md#format-custom-row-between-delimiter), [format_custom_result_before_delimiter](../operations/settings/settings.md#format-custom-result-before-delimiter) and [format_custom_result_after_delimiter](../operations/settings/settings.md#format-custom-result-after-delimiter) settings, not from format strings.
+
+There is also `CustomSeparatedIgnoreSpaces` format, which is similar to [TemplateIgnoreSpaces](#templateignorespaces).
+
+## CustomSeparatedWithNames {#customseparatedwithnames}
+
+Also prints the header row with column names, similar to [TabSeparatedWithNames](#tabseparatedwithnames).
+
+## CustomSeparatedWithNamesAndTypes {#customseparatedwithnamesandtypes}
+
+Also prints two header rows with column names and types, similar to [TabSeparatedWithNamesAndTypes](#tabseparatedwithnamesandtypes).
+
+## JSON {#json}
+
+Outputs data in JSON format. Besides data tables, it also outputs column names and types, along with some additional information: the total number of output rows, and the number of rows that could have been output if there weren’t a LIMIT. Example:
+
+``` sql
+SELECT SearchPhrase, count() AS c FROM test.hits GROUP BY SearchPhrase WITH TOTALS ORDER BY c DESC LIMIT 5 FORMAT JSON
+```
+
+``` json
+{
+        "meta":
+        [
+                {
+                        "name": "'hello'",
+                        "type": "String"
+                },
+                {
+                        "name": "multiply(42, number)",
+                        "type": "UInt64"
+                },
+                {
+                        "name": "range(5)",
+                        "type": "Array(UInt8)"
+                }
+        ],
+
+        "data":
+        [
+                {
+                        "'hello'": "hello",
+                        "multiply(42, number)": "0",
+                        "range(5)": [0,1,2,3,4]
+                },
+                {
+                        "'hello'": "hello",
+                        "multiply(42, number)": "42",
+                        "range(5)": [0,1,2,3,4]
+                },
+                {
+                        "'hello'": "hello",
+                        "multiply(42, number)": "84",
+                        "range(5)": [0,1,2,3,4]
+                }
+        ],
+
+        "rows": 3,
+
+        "rows_before_limit_at_least": 3
+}
+```
+
+The JSON is compatible with JavaScript. To ensure this, some characters are additionally escaped: the slash `/` is escaped as `\/`; alternative line breaks `U+2028` and `U+2029`, which break some browsers, are escaped as `\uXXXX`. ASCII control characters are escaped: backspace, form feed, line feed, carriage return, and horizontal tab are replaced with `\b`, `\f`, `\n`, `\r`, `\t` , as well as the remaining bytes in the 00-1F range using `\uXXXX` sequences. Invalid UTF-8 sequences are changed to the replacement character � so the output text will consist of valid UTF-8 sequences. For compatibility with JavaScript, Int64 and UInt64 integers are enclosed in double-quotes by default. To remove the quotes, you can set the configuration parameter [output_format_json_quote_64bit_integers](../operations/settings/settings.md#session_settings-output_format_json_quote_64bit_integers) to 0.
+
+`rows` – The total number of output rows.
+
+`rows_before_limit_at_least` The minimal number of rows there would have been without LIMIT. Output only if the query contains LIMIT.
+If the query contains GROUP BY, rows_before_limit_at_least is the exact number of rows there would have been without a LIMIT.
+
+`totals` – Total values (when using WITH TOTALS).
+
+`extremes` – Extreme values (when extremes are set to 1).
+
+This format is only appropriate for outputting a query result, but not for parsing (retrieving data to insert in a table).
+
+ClickHouse supports [NULL](../sql-reference/syntax.md), which is displayed as `null` in the JSON output. To enable `+nan`, `-nan`, `+inf`, `-inf` values in output, set the [output_format_json_quote_denormals](../operations/settings/settings.md#settings-output_format_json_quote_denormals) to 1.
+
+**See Also**
+
+-   [JSONEachRow](#jsoneachrow) format
+-   [output_format_json_array_of_rows](../operations/settings/settings.md#output-format-json-array-of-rows) setting
+
+## JSONStrings {#jsonstrings}
+
+Differs from JSON only in that data fields are output in strings, not in typed JSON values.
+
+Example:
+
+```json
+{
+        "meta":
+        [
+                {
+                        "name": "'hello'",
+                        "type": "String"
+                },
+                {
+                        "name": "multiply(42, number)",
+                        "type": "UInt64"
+                },
+                {
+                        "name": "range(5)",
+                        "type": "Array(UInt8)"
+                }
+        ],
+
+        "data":
+        [
+                {
+                        "'hello'": "hello",
+                        "multiply(42, number)": "0",
+                        "range(5)": "[0,1,2,3,4]"
+                },
+                {
+                        "'hello'": "hello",
+                        "multiply(42, number)": "42",
+                        "range(5)": "[0,1,2,3,4]"
+                },
+                {
+                        "'hello'": "hello",
+                        "multiply(42, number)": "84",
+                        "range(5)": "[0,1,2,3,4]"
+                }
+        ],
+
+        "rows": 3,
+
+        "rows_before_limit_at_least": 3
+}
+```
+
+## JSONAsString {#jsonasstring}
+
+In this format, a single JSON object is interpreted as a single value. If the input has several JSON objects (comma separated), they are interpreted as separate rows. If the input data is enclosed in square brackets, it is interpreted as an array of JSONs.
+
+This format can only be parsed for table with a single field of type [String](../sql-reference/data-types/string.md). The remaining columns must be set to [DEFAULT](../sql-reference/statements/create/table.md#default) or [MATERIALIZED](../sql-reference/statements/create/table.md#materialized), or omitted. Once you collect whole JSON object to string you can use [JSON functions](../sql-reference/functions/json-functions.md) to process it.
+
+**Examples**
+
+Query:
+
+``` sql
+DROP TABLE IF EXISTS json_as_string;
+CREATE TABLE json_as_string (json String) ENGINE = Memory;
+INSERT INTO json_as_string (json) FORMAT JSONAsString {"foo":{"bar":{"x":"y"},"baz":1}},{},{"any json stucture":1}
+SELECT * FROM json_as_string;
+```
+
+Result:
+
+``` text
+┌─json──────────────────────────────┐
+│ {"foo":{"bar":{"x":"y"},"baz":1}} │
+│ {}                                │
+│ {"any json stucture":1}           │
+└───────────────────────────────────┘
+```
+
+**An array of JSON objects**
+
+Query:
+
+``` sql
+CREATE TABLE json_square_brackets (field String) ENGINE = Memory;
+INSERT INTO json_square_brackets FORMAT JSONAsString [{"id": 1, "name": "name1"}, {"id": 2, "name": "name2"}];
+
+SELECT * FROM json_square_brackets;
+```
+
+Result:
+
+```text
+┌─field──────────────────────┐
+│ {"id": 1, "name": "name1"} │
+│ {"id": 2, "name": "name2"} │
+└────────────────────────────┘
+```
+
+## JSONCompact {#jsoncompact}
+## JSONCompactStrings {#jsoncompactstrings}
+
+Differs from JSON only in that data rows are output in arrays, not in objects.
+
+Example:
+
+```
+// JSONCompact
+{
+        "meta":
+        [
+                {
+                        "name": "'hello'",
+                        "type": "String"
+                },
+                {
+                        "name": "multiply(42, number)",
+                        "type": "UInt64"
+                },
+                {
+                        "name": "range(5)",
+                        "type": "Array(UInt8)"
+                }
+        ],
+
+        "data":
+        [
+                ["hello", "0", [0,1,2,3,4]],
+                ["hello", "42", [0,1,2,3,4]],
+                ["hello", "84", [0,1,2,3,4]]
+        ],
+
+        "rows": 3,
+
+        "rows_before_limit_at_least": 3
+}
+```
+
+```
+// JSONCompactStrings
+{
+        "meta":
+        [
+                {
+                        "name": "'hello'",
+                        "type": "String"
+                },
+                {
+                        "name": "multiply(42, number)",
+                        "type": "UInt64"
+                },
+                {
+                        "name": "range(5)",
+                        "type": "Array(UInt8)"
+                }
+        ],
+
+        "data":
+        [
+                ["hello", "0", "[0,1,2,3,4]"],
+                ["hello", "42", "[0,1,2,3,4]"],
+                ["hello", "84", "[0,1,2,3,4]"]
+        ],
+
+        "rows": 3,
+
+        "rows_before_limit_at_least": 3
+}
+```
+
+## JSONEachRow {#jsoneachrow}
+## JSONStringsEachRow {#jsonstringseachrow}
+## JSONCompactEachRow {#jsoncompacteachrow}
+## JSONCompactStringsEachRow {#jsoncompactstringseachrow}
+
+When using these formats, ClickHouse outputs rows as separated, newline-delimited JSON values, but the data as a whole is not valid JSON.
+
+``` json
+{"some_int":42,"some_str":"hello","some_tuple":[1,"a"]} // JSONEachRow
+[42,"hello",[1,"a"]] // JSONCompactEachRow
+["42","hello","(2,'a')"] // JSONCompactStringsEachRow
+```
+
+When inserting the data, you should provide a separate JSON value for each row.
+
+## JSONEachRowWithProgress {#jsoneachrowwithprogress}
+## JSONStringsEachRowWithProgress {#jsonstringseachrowwithprogress}
+
+Differs from `JSONEachRow`/`JSONStringsEachRow` in that ClickHouse will also yield progress information as JSON values.
+
+```json
+{"row":{"'hello'":"hello","multiply(42, number)":"0","range(5)":[0,1,2,3,4]}}
+{"row":{"'hello'":"hello","multiply(42, number)":"42","range(5)":[0,1,2,3,4]}}
+{"row":{"'hello'":"hello","multiply(42, number)":"84","range(5)":[0,1,2,3,4]}}
+{"progress":{"read_rows":"3","read_bytes":"24","written_rows":"0","written_bytes":"0","total_rows_to_read":"3"}}
+```
+
+## JSONCompactEachRowWithNames {#jsoncompacteachrowwithnames}
+
+Differs from `JSONCompactEachRow` format in that it also prints the header row with column names, similar to [TabSeparatedWithNames](#tabseparatedwithnames).
+
+## JSONCompactEachRowWithNamesAndTypes {#jsoncompacteachrowwithnamesandtypes}
+
+Differs from `JSONCompactEachRow` format in that it also prints two header rows with column names and types, similar to [TabSeparatedWithNamesAndTypes](#tabseparatedwithnamesandtypes).
+
+## JSONCompactStringsEachRowWithNames {#jsoncompactstringseachrowwithnames}
+
+Differs from `JSONCompactStringsEachRow` in that in that it also prints the header row with column names, similar to [TabSeparatedWithNames](#tabseparatedwithnames).
+
+## JSONCompactStringsEachRowWithNamesAndTypes {#jsoncompactstringseachrowwithnamesandtypes}
+
+Differs from `JSONCompactStringsEachRow` in that it also prints two header rows with column names and types, similar to [TabSeparatedWithNamesAndTypes](#tabseparatedwithnamesandtypes).
+
+```json
+["'hello'", "multiply(42, number)", "range(5)"]
+["String", "UInt64", "Array(UInt8)"]
+["hello", "0", [0,1,2,3,4]]
+["hello", "42", [0,1,2,3,4]]
+["hello", "84", [0,1,2,3,4]]
+```
+
+### Inserting Data {#inserting-data}
+
+``` sql
+INSERT INTO UserActivity FORMAT JSONEachRow {"PageViews":5, "UserID":"4324182021466249494", "Duration":146,"Sign":-1} {"UserID":"4324182021466249494","PageViews":6,"Duration":185,"Sign":1}
+```
+
+ClickHouse allows:
+
+-   Any order of key-value pairs in the object.
+-   Omitting some values.
+
+ClickHouse ignores spaces between elements and commas after the objects. You can pass all the objects in one line. You do not have to separate them with line breaks.
+
+**Omitted values processing**
+
+ClickHouse substitutes omitted values with the default values for the corresponding [data types](../sql-reference/data-types/index.md).
+
+If `DEFAULT expr` is specified, ClickHouse uses different substitution rules depending on the [input_format_defaults_for_omitted_fields](../operations/settings/settings.md#session_settings-input_format_defaults_for_omitted_fields) setting.
+
+Consider the following table:
+
+``` sql
+CREATE TABLE IF NOT EXISTS example_table
+(
+    x UInt32,
+    a DEFAULT x * 2
+) ENGINE = Memory;
+```
+
+-   If `input_format_defaults_for_omitted_fields = 0`, then the default value for `x` and `a` equals `0` (as the default value for the `UInt32` data type).
+-   If `input_format_defaults_for_omitted_fields = 1`, then the default value for `x` equals `0`, but the default value of `a` equals `x * 2`.
+
+:::warning
+When inserting data with `input_format_defaults_for_omitted_fields = 1`, ClickHouse consumes more computational resources, compared to insertion with `input_format_defaults_for_omitted_fields = 0`.
+:::
+
+### Selecting Data {#selecting-data}
+
+Consider the `UserActivity` table as an example:
+
+``` text
+┌──────────────UserID─┬─PageViews─┬─Duration─┬─Sign─┐
+│ 4324182021466249494 │         5 │      146 │   -1 │
+│ 4324182021466249494 │         6 │      185 │    1 │
+└─────────────────────┴───────────┴──────────┴──────┘
+```
+
+The query `SELECT * FROM UserActivity FORMAT JSONEachRow` returns:
+
+``` text
+{"UserID":"4324182021466249494","PageViews":5,"Duration":146,"Sign":-1}
+{"UserID":"4324182021466249494","PageViews":6,"Duration":185,"Sign":1}
+```
+
+Unlike the [JSON](#json) format, there is no substitution of invalid UTF-8 sequences. Values are escaped in the same way as for `JSON`.
+
+:::info    
+Any set of bytes can be output in the strings. Use the `JSONEachRow` format if you are sure that the data in the table can be formatted as JSON without losing any information.
+:::
+
+### Usage of Nested Structures {#jsoneachrow-nested}
+
+If you have a table with [Nested](../sql-reference/data-types/nested-data-structures/nested.md) data type columns, you can insert JSON data with the same structure. Enable this feature with the [input_format_import_nested_json](../operations/settings/settings.md#settings-input_format_import_nested_json) setting.
+
+For example, consider the following table:
+
+``` sql
+CREATE TABLE json_each_row_nested (n Nested (s String, i Int32) ) ENGINE = Memory
+```
+
+As you can see in the `Nested` data type description, ClickHouse treats each component of the nested structure as a separate column (`n.s` and `n.i` for our table). You can insert data in the following way:
+
+``` sql
+INSERT INTO json_each_row_nested FORMAT JSONEachRow {"n.s": ["abc", "def"], "n.i": [1, 23]}
+```
+
+To insert data as a hierarchical JSON object, set [input_format_import_nested_json=1](../operations/settings/settings.md#settings-input_format_import_nested_json).
+
+``` json
+{
+    "n": {
+        "s": ["abc", "def"],
+        "i": [1, 23]
+    }
+}
+```
+
+Without this setting, ClickHouse throws an exception.
+
+``` sql
+SELECT name, value FROM system.settings WHERE name = 'input_format_import_nested_json'
+```
+
+``` text
+┌─name────────────────────────────┬─value─┐
+│ input_format_import_nested_json │ 0     │
+└─────────────────────────────────┴───────┘
+```
+
+``` sql
+INSERT INTO json_each_row_nested FORMAT JSONEachRow {"n": {"s": ["abc", "def"], "i": [1, 23]}}
+```
+
+``` text
+Code: 117. DB::Exception: Unknown field found while parsing JSONEachRow format: n: (at row 1)
+```
+
+``` sql
+SET input_format_import_nested_json=1
+INSERT INTO json_each_row_nested FORMAT JSONEachRow {"n": {"s": ["abc", "def"], "i": [1, 23]}}
+SELECT * FROM json_each_row_nested
+```
+
+``` text
+┌─n.s───────────┬─n.i────┐
+│ ['abc','def'] │ [1,23] │
+└───────────────┴────────┘
+```
+
+## Native {#native}
+
+The most efficient format. Data is written and read by blocks in binary format. For each block, the number of rows, number of columns, column names and types, and parts of columns in this block are recorded one after another. In other words, this format is “columnar” – it does not convert columns to rows. This is the format used in the native interface for interaction between servers, for using the command-line client, and for C++ clients.
+
+You can use this format to quickly generate dumps that can only be read by the ClickHouse DBMS. It does not make sense to work with this format yourself.
+
+## Null {#null}
+
+Nothing is output. However, the query is processed, and when using the command-line client, data is transmitted to the client. This is used for tests, including performance testing.
+Obviously, this format is only appropriate for output, not for parsing.
+
+## Pretty {#pretty}
+
+Outputs data as Unicode-art tables, also using ANSI-escape sequences for setting colours in the terminal.
+A full grid of the table is drawn, and each row occupies two lines in the terminal.
+Each result block is output as a separate table. This is necessary so that blocks can be output without buffering results (buffering would be necessary in order to pre-calculate the visible width of all the values).
+
+[NULL](../sql-reference/syntax.md) is output as `ᴺᵁᴸᴸ`.
+
+Example (shown for the [PrettyCompact](#prettycompact) format):
+
+``` sql
+SELECT * FROM t_null
+```
+
+``` text
+┌─x─┬────y─┐
+│ 1 │ ᴺᵁᴸᴸ │
+└───┴──────┘
+```
+
+Rows are not escaped in Pretty\* formats. Example is shown for the [PrettyCompact](#prettycompact) format:
+
+``` sql
+SELECT 'String with \'quotes\' and \t character' AS Escaping_test
+```
+
+``` text
+┌─Escaping_test────────────────────────┐
+│ String with 'quotes' and      character │
+└──────────────────────────────────────┘
+```
+
+To avoid dumping too much data to the terminal, only the first 10,000 rows are printed. If the number of rows is greater than or equal to 10,000, the message “Showed first 10 000” is printed.
+This format is only appropriate for outputting a query result, but not for parsing (retrieving data to insert in a table).
+
+The Pretty format supports outputting total values (when using WITH TOTALS) and extremes (when ‘extremes’ is set to 1). In these cases, total values and extreme values are output after the main data, in separate tables. Example (shown for the [PrettyCompact](#prettycompact) format):
+
+``` sql
+SELECT EventDate, count() AS c FROM test.hits GROUP BY EventDate WITH TOTALS ORDER BY EventDate FORMAT PrettyCompact
+```
+
+``` text
+┌──EventDate─┬───────c─┐
+│ 2014-03-17 │ 1406958 │
+│ 2014-03-18 │ 1383658 │
+│ 2014-03-19 │ 1405797 │
+│ 2014-03-20 │ 1353623 │
+│ 2014-03-21 │ 1245779 │
+│ 2014-03-22 │ 1031592 │
+│ 2014-03-23 │ 1046491 │
+└────────────┴─────────┘
+
+Totals:
+┌──EventDate─┬───────c─┐
+│ 1970-01-01 │ 8873898 │
+└────────────┴─────────┘
+
+Extremes:
+┌──EventDate─┬───────c─┐
+│ 2014-03-17 │ 1031592 │
+│ 2014-03-23 │ 1406958 │
+└────────────┴─────────┘
+```
+
+## PrettyCompact {#prettycompact}
+
+Differs from [Pretty](#pretty) in that the grid is drawn between rows and the result is more compact.
+This format is used by default in the command-line client in interactive mode.
+
+## PrettyCompactMonoBlock {#prettycompactmonoblock}
+
+Differs from [PrettyCompact](#prettycompact) in that up to 10,000 rows are buffered, then output as a single table, not by blocks.
+
+## PrettyNoEscapes {#prettynoescapes}
+
+Differs from Pretty in that ANSI-escape sequences aren’t used. This is necessary for displaying this format in a browser, as well as for using the ‘watch’ command-line utility.
+
+Example:
+
+``` bash
+$ watch -n1 "clickhouse-client --query='SELECT event, value FROM system.events FORMAT PrettyCompactNoEscapes'"
+```
+
+You can use the HTTP interface for displaying in the browser.
+
+### PrettyCompactNoEscapes {#prettycompactnoescapes}
+
+The same as the previous setting.
+
+### PrettySpaceNoEscapes {#prettyspacenoescapes}
+
+The same as the previous setting.
+
+## PrettySpace {#prettyspace}
+
+Differs from [PrettyCompact](#prettycompact) in that whitespace (space characters) is used instead of the grid.
+
+## RowBinary {#rowbinary}
+
+Formats and parses data by row in binary format. Rows and values are listed consecutively, without separators.
+This format is less efficient than the Native format since it is row-based.
+
+Integers use fixed-length little-endian representation. For example, UInt64 uses 8 bytes.
+DateTime is represented as UInt32 containing the Unix timestamp as the value.
+Date is represented as a UInt16 object that contains the number of days since 1970-01-01 as the value.
+String is represented as a varint length (unsigned [LEB128](https://en.wikipedia.org/wiki/LEB128)), followed by the bytes of the string.
+FixedString is represented simply as a sequence of bytes.
+
+Array is represented as a varint length (unsigned [LEB128](https://en.wikipedia.org/wiki/LEB128)), followed by successive elements of the array.
+
+For [NULL](../sql-reference/syntax.md#null-literal) support, an additional byte containing 1 or 0 is added before each [Nullable](../sql-reference/data-types/nullable.md) value. If 1, then the value is `NULL` and this byte is interpreted as a separate value. If 0, the value after the byte is not `NULL`.
+
+## RowBinaryWithNames {#rowbinarywithnames}
+
+Similar to [RowBinary](#rowbinary), but with added header:
+
+-   [LEB128](https://en.wikipedia.org/wiki/LEB128)-encoded number of columns (N)
+-   N `String`s specifying column names
+
+## RowBinaryWithNamesAndTypes {#rowbinarywithnamesandtypes}
+
+Similar to [RowBinary](#rowbinary), but with added header:
+
+-   [LEB128](https://en.wikipedia.org/wiki/LEB128)-encoded number of columns (N)
+-   N `String`s specifying column names
+-   N `String`s specifying column types
+
+## Values {#data-format-values}
+
+Prints every row in brackets. Rows are separated by commas. There is no comma after the last row. The values inside the brackets are also comma-separated. Numbers are output in a decimal format without quotes. Arrays are output in square brackets. Strings, dates, and dates with times are output in quotes. Escaping rules and parsing are similar to the [TabSeparated](#tabseparated) format. During formatting, extra spaces aren’t inserted, but during parsing, they are allowed and skipped (except for spaces inside array values, which are not allowed). [NULL](../sql-reference/syntax.md) is represented as `NULL`.
+
+The minimum set of characters that you need to escape when passing data in Values ​​format: single quotes and backslashes.
+
+This is the format that is used in `INSERT INTO t VALUES ...`, but you can also use it for formatting query results.
+
+See also: [input_format_values_interpret_expressions](../operations/settings/settings.md#settings-input_format_values_interpret_expressions) and [input_format_values_deduce_templates_of_expressions](../operations/settings/settings.md#settings-input_format_values_deduce_templates_of_expressions) settings.
+
+## Vertical {#vertical}
+
+Prints each value on a separate line with the column name specified. This format is convenient for printing just one or a few rows if each row consists of a large number of columns.
+
+[NULL](../sql-reference/syntax.md) is output as `ᴺᵁᴸᴸ`.
+
+Example:
+
+``` sql
+SELECT * FROM t_null FORMAT Vertical
+```
+
+``` text
+Row 1:
+──────
+x: 1
+y: ᴺᵁᴸᴸ
+```
+
+Rows are not escaped in Vertical format:
+
+``` sql
+SELECT 'string with \'quotes\' and \t with some special \n characters' AS test FORMAT Vertical
+```
+
+``` text
+Row 1:
+──────
+test: string with 'quotes' and      with some special
+ characters
+```
+
+This format is only appropriate for outputting a query result, but not for parsing (retrieving data to insert in a table).
+
+## XML {#xml}
+
+XML format is suitable only for output, not for parsing. Example:
+
+``` xml
+<?xml version='1.0' encoding='UTF-8' ?>
+<result>
+        <meta>
+                <columns>
+                        <column>
+                                <name>SearchPhrase</name>
+                                <type>String</type>
+                        </column>
+                        <column>
+                                <name>count()</name>
+                                <type>UInt64</type>
+                        </column>
+                </columns>
+        </meta>
+        <data>
+                <row>
+                        <SearchPhrase></SearchPhrase>
+                        <field>8267016</field>
+                </row>
+                <row>
+                        <SearchPhrase>bathroom interior design</SearchPhrase>
+                        <field>2166</field>
+                </row>
+                <row>
+                        <SearchPhrase>clickhouse</SearchPhrase>
+                        <field>1655</field>
+                </row>
+                <row>
+                        <SearchPhrase>2014 spring fashion</SearchPhrase>
+                        <field>1549</field>
+                </row>
+                <row>
+                        <SearchPhrase>freeform photos</SearchPhrase>
+                        <field>1480</field>
+                </row>
+                <row>
+                        <SearchPhrase>angelina jolie</SearchPhrase>
+                        <field>1245</field>
+                </row>
+                <row>
+                        <SearchPhrase>omsk</SearchPhrase>
+                        <field>1112</field>
+                </row>
+                <row>
+                        <SearchPhrase>photos of dog breeds</SearchPhrase>
+                        <field>1091</field>
+                </row>
+                <row>
+                        <SearchPhrase>curtain designs</SearchPhrase>
+                        <field>1064</field>
+                </row>
+                <row>
+                        <SearchPhrase>baku</SearchPhrase>
+                        <field>1000</field>
+                </row>
+        </data>
+        <rows>10</rows>
+        <rows_before_limit_at_least>141137</rows_before_limit_at_least>
+</result>
+```
+
+If the column name does not have an acceptable format, just ‘field’ is used as the element name. In general, the XML structure follows the JSON structure.
+Just as for JSON, invalid UTF-8 sequences are changed to the replacement character � so the output text will consist of valid UTF-8 sequences.
+
+In string values, the characters `<` and `&` are escaped as `<` and `&`.
+
+Arrays are output as `<array><elem>Hello</elem><elem>World</elem>...</array>`,and tuples as `<tuple><elem>Hello</elem><elem>World</elem>...</tuple>`.
+
+## CapnProto {#capnproto}
+
+CapnProto is a binary message format similar to [Protocol Buffers](https://developers.google.com/protocol-buffers/) and [Thrift](https://en.wikipedia.org/wiki/Apache_Thrift), but not like [JSON](#json) or [MessagePack](https://msgpack.org/).
+
+CapnProto messages are strictly typed and not self-describing, meaning they need an external schema description. The schema is applied on the fly and cached for each query.
+
+See also [Format Schema](#formatschema).
+
+### Data Types Matching {#data_types-matching-capnproto}
+
+The table below shows supported data types and how they match ClickHouse [data types](../sql-reference/data-types/index.md) in `INSERT` and `SELECT` queries.
+
+| CapnProto data type (`INSERT`) | ClickHouse data type                                      | CapnProto data type (`SELECT`) |
+|--------------------------------|-----------------------------------------------------------|--------------------------------|
+| `UINT8`, `BOOL`                | [UInt8](../sql-reference/data-types/int-uint.md)          | `UINT8`                        |
+| `INT8`                         | [Int8](../sql-reference/data-types/int-uint.md)           | `INT8`                         |
+| `UINT16`                       | [UInt16](../sql-reference/data-types/int-uint.md), [Date](../sql-reference/data-types/date.md)         | `UINT16`                       |
+| `INT16`                        | [Int16](../sql-reference/data-types/int-uint.md)          | `INT16`                        |
+| `UINT32`                       | [UInt32](../sql-reference/data-types/int-uint.md), [DateTime](../sql-reference/data-types/datetime.md)         | `UINT32`                       |
+| `INT32`                        | [Int32](../sql-reference/data-types/int-uint.md)          | `INT32`                        |
+| `UINT64`                       | [UInt64](../sql-reference/data-types/int-uint.md)         | `UINT64`                       |
+| `INT64`                        | [Int64](../sql-reference/data-types/int-uint.md), [DateTime64](../sql-reference/data-types/datetime.md)          | `INT64`                        |
+| `FLOAT32`                      | [Float32](../sql-reference/data-types/float.md)           | `FLOAT32`                      |
+| `FLOAT64`                      | [Float64](../sql-reference/data-types/float.md)           | `FLOAT64`                      |
+| `TEXT, DATA`                   | [String](../sql-reference/data-types/string.md), [FixedString](../sql-reference/data-types/fixedstring.md)               | `TEXT, DATA`                       |
+| `union(T, Void), union(Void, T)`          | [Nullable(T)](../sql-reference/data-types/date.md)       | `union(T, Void), union(Void, T)`                       |
+| `ENUM`                         | [Enum(8\|16)](../sql-reference/data-types/enum.md)        | `ENUM`                         |
+| `LIST`                         | [Array](../sql-reference/data-types/array.md)             | `LIST`                         |
+| `STRUCT`                       | [Tuple](../sql-reference/data-types/tuple.md)             | `STRUCT`                       |
+
+For working with `Enum` in CapnProto format use the [format_capn_proto_enum_comparising_mode](../operations/settings/settings.md#format-capn-proto-enum-comparising-mode) setting.
+
+Arrays can be nested and can have a value of the `Nullable` type as an argument. `Tuple` type also can be nested.
+
+### Inserting and Selecting Data {#inserting-and-selecting-data-capnproto}
+
+You can insert CapnProto data from a file into ClickHouse table by the following command:
+
+``` bash
+$ cat capnproto_messages.bin | clickhouse-client --query "INSERT INTO test.hits FORMAT CapnProto SETTINGS format_schema = 'schema:Message'"
+```
+
+Where `schema.capnp` looks like this:
+
+``` capnp
+struct Message {
+  SearchPhrase @0 :Text;
+  c @1 :Uint64;
+}
+```
+
+You can select data from a ClickHouse table and save them into some file in the CapnProto format by the following command:
+
+``` bash
+$ clickhouse-client --query = "SELECT * FROM test.hits FORMAT CapnProto SETTINGS format_schema = 'schema:Message'"
+```
+
+## Protobuf {#protobuf}
+
+Protobuf - is a [Protocol Buffers](https://developers.google.com/protocol-buffers/) format.
+
+This format requires an external format schema. The schema is cached between queries.
+ClickHouse supports both `proto2` and `proto3` syntaxes. Repeated/optional/required fields are supported.
+
+Usage examples:
+
+``` sql
+SELECT * FROM test.table FORMAT Protobuf SETTINGS format_schema = 'schemafile:MessageType'
+```
+
+``` bash
+cat protobuf_messages.bin | clickhouse-client --query "INSERT INTO test.table FORMAT Protobuf SETTINGS format_schema='schemafile:MessageType'"
+```
+
+where the file `schemafile.proto` looks like this:
+
+``` capnp
+syntax = "proto3";
+
+message MessageType {
+  string name = 1;
+  string surname = 2;
+  uint32 birthDate = 3;
+  repeated string phoneNumbers = 4;
+};
+```
+
+To find the correspondence between table columns and fields of Protocol Buffers’ message type ClickHouse compares their names.
+This comparison is case-insensitive and the characters `_` (underscore) and `.` (dot) are considered as equal.
+If types of a column and a field of Protocol Buffers’ message are different the necessary conversion is applied.
+
+Nested messages are supported. For example, for the field `z` in the following message type
+
+``` capnp
+message MessageType {
+  message XType {
+    message YType {
+      int32 z;
+    };
+    repeated YType y;
+  };
+  XType x;
+};
+```
+
+ClickHouse tries to find a column named `x.y.z` (or `x_y_z` or `X.y_Z` and so on).
+Nested messages are suitable to input or output a [nested data structures](../sql-reference/data-types/nested-data-structures/nested.md).
+
+Default values defined in a protobuf schema like this
+
+``` capnp
+syntax = "proto2";
+
+message MessageType {
+  optional int32 result_per_page = 3 [default = 10];
+}
+```
+
+are not applied; the [table defaults](../sql-reference/statements/create/table.md#create-default-values) are used instead of them.
+
+ClickHouse inputs and outputs protobuf messages in the `length-delimited` format.
+It means before every message should be written its length as a [varint](https://developers.google.com/protocol-buffers/docs/encoding#varints).
+See also [how to read/write length-delimited protobuf messages in popular languages](https://cwiki.apache.org/confluence/display/GEODE/Delimiting+Protobuf+Messages).
+
+## ProtobufSingle {#protobufsingle}
+
+Same as [Protobuf](#protobuf) but for storing/parsing single Protobuf message without length delimiters.
+
+## Avro {#data-format-avro}
+
+[Apache Avro](https://avro.apache.org/) is a row-oriented data serialization framework developed within Apache’s Hadoop project.
+
+ClickHouse Avro format supports reading and writing [Avro data files](https://avro.apache.org/docs/current/spec.html#Object+Container+Files).
+
+### Data Types Matching {#data_types-matching}
+
+The table below shows supported data types and how they match ClickHouse [data types](../sql-reference/data-types/index.md) in `INSERT` and `SELECT` queries.
+
+| Avro data type `INSERT`                     | ClickHouse data type                                                                                                  | Avro data type `SELECT`      |
+|---------------------------------------------|-----------------------------------------------------------------------------------------------------------------------|------------------------------|
+| `boolean`, `int`, `long`, `float`, `double` | [Int(8\|16\|32)](../sql-reference/data-types/int-uint.md), [UInt(8\|16\|32)](../sql-reference/data-types/int-uint.md) | `int`                        |
+| `boolean`, `int`, `long`, `float`, `double` | [Int64](../sql-reference/data-types/int-uint.md), [UInt64](../sql-reference/data-types/int-uint.md)                   | `long`                       |
+| `boolean`, `int`, `long`, `float`, `double` | [Float32](../sql-reference/data-types/float.md)                                                                       | `float`                      |
+| `boolean`, `int`, `long`, `float`, `double` | [Float64](../sql-reference/data-types/float.md)                                                                       | `double`                     |
+| `bytes`, `string`, `fixed`, `enum`          | [String](../sql-reference/data-types/string.md)                                                                       | `bytes` or `string` \*       |
+| `bytes`, `string`, `fixed`                  | [FixedString(N)](../sql-reference/data-types/fixedstring.md)                                                          | `fixed(N)`                   |
+| `enum`                                      | [Enum(8\|16)](../sql-reference/data-types/enum.md)                                                                    | `enum`                       |
+| `array(T)`                                  | [Array(T)](../sql-reference/data-types/array.md)                                                                      | `array(T)`                   |
+| `union(null, T)`, `union(T, null)`          | [Nullable(T)](../sql-reference/data-types/date.md)                                                                    | `union(null, T)`             |
+| `null`                                      | [Nullable(Nothing)](../sql-reference/data-types/special-data-types/nothing.md)                                        | `null`                       |
+| `int (date)` \**                            | [Date](../sql-reference/data-types/date.md)                                                                           | `int (date)` \**             |
+| `long (timestamp-millis)` \**               | [DateTime64(3)](../sql-reference/data-types/datetime.md)                                                              | `long (timestamp-millis)` \* |
+| `long (timestamp-micros)` \**               | [DateTime64(6)](../sql-reference/data-types/datetime.md)                                                              | `long (timestamp-micros)` \* |
+
+\* `bytes` is default, controlled by [output_format_avro_string_column_pattern](../operations/settings/settings.md#settings-output_format_avro_string_column_pattern)
+\** [Avro logical types](https://avro.apache.org/docs/current/spec.html#Logical+Types)
+
+Unsupported Avro data types: `record` (non-root), `map`
+
+Unsupported Avro logical data types: `time-millis`, `time-micros`, `duration`
+
+### Inserting Data {#inserting-data-1}
+
+To insert data from an Avro file into ClickHouse table:
+
+``` bash
+$ cat file.avro | clickhouse-client --query="INSERT INTO {some_table} FORMAT Avro"
+```
+
+The root schema of input Avro file must be of `record` type.
+
+To find the correspondence between table columns and fields of Avro schema ClickHouse compares their names. This comparison is case-sensitive.
+Unused fields are skipped.
+
+Data types of ClickHouse table columns can differ from the corresponding fields of the Avro data inserted. When inserting data, ClickHouse interprets data types according to the table above and then [casts](../sql-reference/functions/type-conversion-functions.md#type_conversion_function-cast) the data to corresponding column type.
+
+### Selecting Data {#selecting-data-1}
+
+To select data from ClickHouse table into an Avro file:
+
+``` bash
+$ clickhouse-client --query="SELECT * FROM {some_table} FORMAT Avro" > file.avro
+```
+
+Column names must:
+
+-   start with `[A-Za-z_]`
+-   subsequently contain only `[A-Za-z0-9_]`
+
+Output Avro file compression and sync interval can be configured with [output_format_avro_codec](../operations/settings/settings.md#settings-output_format_avro_codec) and [output_format_avro_sync_interval](../operations/settings/settings.md#settings-output_format_avro_sync_interval) respectively.
+
+## AvroConfluent {#data-format-avro-confluent}
+
+AvroConfluent supports decoding single-object Avro messages commonly used with [Kafka](https://kafka.apache.org/) and [Confluent Schema Registry](https://docs.confluent.io/current/schema-registry/index.html).
+
+Each Avro message embeds a schema id that can be resolved to the actual schema with help of the Schema Registry.
+
+Schemas are cached once resolved.
+
+Schema Registry URL is configured with [format_avro_schema_registry_url](../operations/settings/settings.md#format_avro_schema_registry_url).
+
+### Data Types Matching {#data_types-matching-1}
+
+Same as [Avro](#data-format-avro).
+
+### Usage {#usage}
+
+To quickly verify schema resolution you can use [kafkacat](https://github.com/edenhill/kafkacat) with [clickhouse-local](../operations/utilities/clickhouse-local.md):
+
+``` bash
+$ kafkacat -b kafka-broker  -C -t topic1 -o beginning -f '%s' -c 3 | clickhouse-local   --input-format AvroConfluent --format_avro_schema_registry_url 'http://schema-registry' -S "field1 Int64, field2 String"  -q 'select *  from table'
+1 a
+2 b
+3 c
+```
+
+To use `AvroConfluent` with [Kafka](../engines/table-engines/integrations/kafka.md):
+
+``` sql
+CREATE TABLE topic1_stream
+(
+    field1 String,
+    field2 String
+)
+ENGINE = Kafka()
+SETTINGS
+kafka_broker_list = 'kafka-broker',
+kafka_topic_list = 'topic1',
+kafka_group_name = 'group1',
+kafka_format = 'AvroConfluent';
+
+SET format_avro_schema_registry_url = 'http://schema-registry';
+
+SELECT * FROM topic1_stream;
+```
+
+:::warning    
+Setting `format_avro_schema_registry_url` needs to be configured in `users.xml` to maintain it’s value after a restart. Also you can use the `format_avro_schema_registry_url` setting of the `Kafka` table engine.
+:::
+
+## Parquet {#data-format-parquet}
+
+[Apache Parquet](https://parquet.apache.org/) is a columnar storage format widespread in the Hadoop ecosystem. ClickHouse supports read and write operations for this format.
+
+### Data Types Matching {#data_types-matching-2}
+
+The table below shows supported data types and how they match ClickHouse [data types](../sql-reference/data-types/index.md) in `INSERT` and `SELECT` queries.
+
+| Parquet data type (`INSERT`) | ClickHouse data type                                      | Parquet data type (`SELECT`) |
+|------------------------------|-----------------------------------------------------------|------------------------------|
+| `UINT8`, `BOOL`              | [UInt8](../sql-reference/data-types/int-uint.md)          | `UINT8`                      |
+| `INT8`                       | [Int8](../sql-reference/data-types/int-uint.md)           | `INT8`                       |
+| `UINT16`                     | [UInt16](../sql-reference/data-types/int-uint.md)         | `UINT16`                     |
+| `INT16`                      | [Int16](../sql-reference/data-types/int-uint.md)          | `INT16`                      |
+| `UINT32`                     | [UInt32](../sql-reference/data-types/int-uint.md)         | `UINT32`                     |
+| `INT32`                      | [Int32](../sql-reference/data-types/int-uint.md)          | `INT32`                      |
+| `UINT64`                     | [UInt64](../sql-reference/data-types/int-uint.md)         | `UINT64`                     |
+| `INT64`                      | [Int64](../sql-reference/data-types/int-uint.md)          | `INT64`                      |
+| `FLOAT`, `HALF_FLOAT`        | [Float32](../sql-reference/data-types/float.md)           | `FLOAT`                      |
+| `DOUBLE`                     | [Float64](../sql-reference/data-types/float.md)           | `DOUBLE`                     |
+| `DATE32`                     | [Date](../sql-reference/data-types/date.md)               | `UINT16`                     |
+| `DATE64`, `TIMESTAMP`        | [DateTime](../sql-reference/data-types/datetime.md)       | `UINT32`                     |
+| `STRING`, `BINARY`           | [String](../sql-reference/data-types/string.md)           | `BINARY`                     |
+| —                            | [FixedString](../sql-reference/data-types/fixedstring.md) | `BINARY`                     |
+| `DECIMAL`                    | [Decimal](../sql-reference/data-types/decimal.md)         | `DECIMAL`                    |
+| `LIST`                       | [Array](../sql-reference/data-types/array.md)             | `LIST`                       |
+| `STRUCT`                     | [Tuple](../sql-reference/data-types/tuple.md)             | `STRUCT`                     |
+| `MAP`                        | [Map](../sql-reference/data-types/map.md)                 | `MAP`                        |
+
+Arrays can be nested and can have a value of the `Nullable` type as an argument. `Tuple` and `Map` types also can be nested.
+
+ClickHouse supports configurable precision of `Decimal` type. The `INSERT` query treats the Parquet `DECIMAL` type as the ClickHouse `Decimal128` type.
+
+Unsupported Parquet data types: `TIME32`, `FIXED_SIZE_BINARY`, `JSON`, `UUID`, `ENUM`.
+
+Data types of ClickHouse table columns can differ from the corresponding fields of the Parquet data inserted. When inserting data, ClickHouse interprets data types according to the table above and then [cast](../sql-reference/functions/type-conversion-functions/#type_conversion_function-cast) the data to that data type which is set for the ClickHouse table column.
+
+### Inserting and Selecting Data {#inserting-and-selecting-data}
+
+You can insert Parquet data from a file into ClickHouse table by the following command:
+
+``` bash
+$ cat {filename} | clickhouse-client --query="INSERT INTO {some_table} FORMAT Parquet"
+```
+
+To insert data into [Nested](../sql-reference/data-types/nested-data-structures/nested.md) columns as an array of structs values you must switch on the [input_format_parquet_import_nested](../operations/settings/settings.md#input_format_parquet_import_nested) setting.
+
+You can select data from a ClickHouse table and save them into some file in the Parquet format by the following command:
+
+``` bash
+$ clickhouse-client --query="SELECT * FROM {some_table} FORMAT Parquet" > {some_file.pq}
+```
+
+To exchange data with Hadoop, you can use [HDFS table engine](../engines/table-engines/integrations/hdfs.md).
+
+## Arrow {#data-format-arrow}
+
+[Apache Arrow](https://arrow.apache.org/) comes with two built-in columnar storage formats. ClickHouse supports read and write operations for these formats.
+
+`Arrow` is Apache Arrow’s "file mode" format. It is designed for in-memory random access.
+
+### Data Types Matching {#data_types-matching-arrow}
+
+The table below shows supported data types and how they match ClickHouse [data types](../sql-reference/data-types/index.md) in `INSERT` and `SELECT` queries.
+
+| Arrow data type (`INSERT`) | ClickHouse data type                                | Arrow data type (`SELECT`) |
+|----------------------------|-----------------------------------------------------|----------------------------|
+| `UINT8`, `BOOL`            | [UInt8](../sql-reference/data-types/int-uint.md)    | `UINT8`                    |
+| `INT8`                     | [Int8](../sql-reference/data-types/int-uint.md)     | `INT8`                     |
+| `UINT16`                   | [UInt16](../sql-reference/data-types/int-uint.md)   | `UINT16`                   |
+| `INT16`                    | [Int16](../sql-reference/data-types/int-uint.md)    | `INT16`                    |
+| `UINT32`                   | [UInt32](../sql-reference/data-types/int-uint.md)   | `UINT32`                   |
+| `INT32`                    | [Int32](../sql-reference/data-types/int-uint.md)    | `INT32`                    |
+| `UINT64`                   | [UInt64](../sql-reference/data-types/int-uint.md)   | `UINT64`                   |
+| `INT64`                    | [Int64](../sql-reference/data-types/int-uint.md)    | `INT64`                    |
+| `FLOAT`, `HALF_FLOAT`      | [Float32](../sql-reference/data-types/float.md)     | `FLOAT32`                  |
+| `DOUBLE`                   | [Float64](../sql-reference/data-types/float.md)     | `FLOAT64`                  |
+| `DATE32`                   | [Date](../sql-reference/data-types/date.md)         | `UINT16`                   |
+| `DATE64`, `TIMESTAMP`      | [DateTime](../sql-reference/data-types/datetime.md) | `UINT32`                   |
+| `STRING`, `BINARY`         | [String](../sql-reference/data-types/string.md)     | `BINARY`                   |
+| `STRING`, `BINARY`         | [FixedString](../sql-reference/data-types/fixedstring.md)   | `BINARY`                        |
+| `DECIMAL`                  | [Decimal](../sql-reference/data-types/decimal.md)   | `DECIMAL`                  |
+| `DECIMAL256`               | [Decimal256](../sql-reference/data-types/decimal.md)| `DECIMAL256`               |
+| `LIST`                     | [Array](../sql-reference/data-types/array.md)       | `LIST`                     |
+| `STRUCT`                   | [Tuple](../sql-reference/data-types/tuple.md)       | `STRUCT`                 |
+| `MAP`                      | [Map](../sql-reference/data-types/map.md)           | `MAP`                    |
+
+Arrays can be nested and can have a value of the `Nullable` type as an argument. `Tuple` and `Map` types also can be nested.
+
+The `DICTIONARY` type is supported for `INSERT` queries, and for `SELECT` queries there is an [output_format_arrow_low_cardinality_as_dictionary](../operations/settings/settings.md#output-format-arrow-low-cardinality-as-dictionary) setting that allows to output [LowCardinality](../sql-reference/data-types/lowcardinality.md) type as a `DICTIONARY` type.
+
+ClickHouse supports configurable precision of the `Decimal` type. The `INSERT` query treats the Arrow `DECIMAL` type as the ClickHouse `Decimal128` type.
+
+Unsupported Arrow data types: `TIME32`, `FIXED_SIZE_BINARY`, `JSON`, `UUID`, `ENUM`.
+
+The data types of ClickHouse table columns do not have to match the corresponding Arrow data fields. When inserting data, ClickHouse interprets data types according to the table above and then [casts](../sql-reference/functions/type-conversion-functions.md#type_conversion_function-cast) the data to the data type set for the ClickHouse table column.
+
+### Inserting Data {#inserting-data-arrow}
+
+You can insert Arrow data from a file into ClickHouse table by the following command:
+
+``` bash
+$ cat filename.arrow | clickhouse-client --query="INSERT INTO some_table FORMAT Arrow"
+```
+
+To insert data into [Nested](../sql-reference/data-types/nested-data-structures/nested.md) columns as an array of structs values you must switch on the [input_format_arrow_import_nested](../operations/settings/settings.md#input_format_arrow_import_nested) setting.
+
+### Selecting Data {#selecting-data-arrow}
+
+You can select data from a ClickHouse table and save them into some file in the Arrow format by the following command:
+
+``` bash
+$ clickhouse-client --query="SELECT * FROM {some_table} FORMAT Arrow" > {filename.arrow}
+```
+
+## ArrowStream {#data-format-arrow-stream}
+
+`ArrowStream` is Apache Arrow’s “stream mode” format. It is designed for in-memory stream processing.
+
+## ORC {#data-format-orc}
+
+[Apache ORC](https://orc.apache.org/) is a columnar storage format widespread in the [Hadoop](https://hadoop.apache.org/) ecosystem.
+
+### Data Types Matching {#data_types-matching-3}
+
+The table below shows supported data types and how they match ClickHouse [data types](../sql-reference/data-types/index.md) in `INSERT` and `SELECT` queries.
+
+| ORC data type (`INSERT`) | ClickHouse data type                                | ORC data type (`SELECT`) |
+|--------------------------|-----------------------------------------------------|--------------------------|
+| `UINT8`, `BOOL`          | [UInt8](../sql-reference/data-types/int-uint.md)    | `UINT8`                  |
+| `INT8`                   | [Int8](../sql-reference/data-types/int-uint.md)     | `INT8`                   |
+| `UINT16`                 | [UInt16](../sql-reference/data-types/int-uint.md)   | `UINT16`                 |
+| `INT16`                  | [Int16](../sql-reference/data-types/int-uint.md)    | `INT16`                  |
+| `UINT32`                 | [UInt32](../sql-reference/data-types/int-uint.md)   | `UINT32`                 |
+| `INT32`                  | [Int32](../sql-reference/data-types/int-uint.md)    | `INT32`                  |
+| `UINT64`                 | [UInt64](../sql-reference/data-types/int-uint.md)   | `UINT64`                 |
+| `INT64`                  | [Int64](../sql-reference/data-types/int-uint.md)    | `INT64`                  |
+| `FLOAT`, `HALF_FLOAT`    | [Float32](../sql-reference/data-types/float.md)     | `FLOAT`                  |
+| `DOUBLE`                 | [Float64](../sql-reference/data-types/float.md)     | `DOUBLE`                 |
+| `DATE32`                 | [Date](../sql-reference/data-types/date.md)         | `DATE32`                 |
+| `DATE64`, `TIMESTAMP`    | [DateTime](../sql-reference/data-types/datetime.md) | `TIMESTAMP`              |
+| `STRING`, `BINARY`       | [String](../sql-reference/data-types/string.md)     | `BINARY`                 |
+| `DECIMAL`                | [Decimal](../sql-reference/data-types/decimal.md)   | `DECIMAL`                |
+| `LIST`                   | [Array](../sql-reference/data-types/array.md)       | `LIST`                   |
+| `STRUCT`                 | [Tuple](../sql-reference/data-types/tuple.md)       | `STRUCT`                 |
+| `MAP`                    | [Map](../sql-reference/data-types/map.md)           | `MAP`                    |
+
+Arrays can be nested and can have a value of the `Nullable` type as an argument. `Tuple` and `Map` types also can be nested.
+
+ClickHouse supports configurable precision of the `Decimal` type. The `INSERT` query treats the ORC `DECIMAL` type as the ClickHouse `Decimal128` type.
+
+Unsupported ORC data types: `TIME32`, `FIXED_SIZE_BINARY`, `JSON`, `UUID`, `ENUM`.
+
+The data types of ClickHouse table columns do not have to match the corresponding ORC data fields. When inserting data, ClickHouse interprets data types according to the table above and then [casts](../sql-reference/functions/type-conversion-functions.md#type_conversion_function-cast) the data to the data type set for the ClickHouse table column.
+
+### Inserting Data {#inserting-data-2}
+
+You can insert ORC data from a file into ClickHouse table by the following command:
+
+``` bash
+$ cat filename.orc | clickhouse-client --query="INSERT INTO some_table FORMAT ORC"
+```
+
+To insert data into [Nested](../sql-reference/data-types/nested-data-structures/nested.md) columns as an array of structs values you must switch on the [input_format_orc_import_nested](../operations/settings/settings.md#input_format_orc_import_nested) setting.
+
+### Selecting Data {#selecting-data-2}
+
+You can select data from a ClickHouse table and save them into some file in the ORC format by the following command:
+
+``` bash
+$ clickhouse-client --query="SELECT * FROM {some_table} FORMAT ORC" > {filename.orc}
+```
+
+To exchange data with Hadoop, you can use [HDFS table engine](../engines/table-engines/integrations/hdfs.md).
+
+## LineAsString {#lineasstring}
+
+In this format, every line of input data is interpreted as a single string value. This format can only be parsed for table with a single field of type [String](../sql-reference/data-types/string.md). The remaining columns must be set to [DEFAULT](../sql-reference/statements/create/table.md#default) or [MATERIALIZED](../sql-reference/statements/create/table.md#materialized), or omitted.
+
+**Example**
+
+Query:
+
+``` sql
+DROP TABLE IF EXISTS line_as_string;
+CREATE TABLE line_as_string (field String) ENGINE = Memory;
+INSERT INTO line_as_string FORMAT LineAsString "I love apple", "I love banana", "I love orange";
+SELECT * FROM line_as_string;
+```
+
+Result:
+
+``` text
+┌─field─────────────────────────────────────────────┐
+│ "I love apple", "I love banana", "I love orange"; │
+└───────────────────────────────────────────────────┘
+```
+
+## Regexp {#data-format-regexp}
+
+Each line of imported data is parsed according to the regular expression.
+
+When working with the `Regexp` format, you can use the following settings:
+
+-   `format_regexp` — [String](../sql-reference/data-types/string.md). Contains regular expression in the [re2](https://github.com/google/re2/wiki/Syntax) format.
+
+-   `format_regexp_escaping_rule` — [String](../sql-reference/data-types/string.md). The following escaping rules are supported:
+
+    -   CSV (similarly to [CSV](#csv))
+    -   JSON (similarly to [JSONEachRow](#jsoneachrow))
+    -   Escaped (similarly to [TSV](#tabseparated))
+    -   Quoted (similarly to [Values](#data-format-values))
+    -   Raw (extracts subpatterns as a whole, no escaping rules, similarly to [TSVRaw](#tabseparatedraw))
+	
+-   `format_regexp_skip_unmatched` — [UInt8](../sql-reference/data-types/int-uint.md). Defines the need to throw an exeption in case the `format_regexp` expression does not match the imported data. Can be set to `0` or `1`.
+
+**Usage**
+
+The regular expression from `format_regexp` setting is applied to every line of imported data. The number of subpatterns in the regular expression must be equal to the number of columns in imported dataset.
+
+Lines of the imported data must be separated by newline character `'\n'` or DOS-style newline `"\r\n"`.
+
+The content of every matched subpattern is parsed with the method of corresponding data type, according to `format_regexp_escaping_rule` setting.
+
+If the regular expression does not match the line and `format_regexp_skip_unmatched` is set to 1, the line is silently skipped. If `format_regexp_skip_unmatched` is set to 0, exception is thrown.
+
+**Example**
+
+Consider the file data.tsv:
+
+```text
+id: 1 array: [1,2,3] string: str1 date: 2020-01-01
+id: 2 array: [1,2,3] string: str2 date: 2020-01-02
+id: 3 array: [1,2,3] string: str3 date: 2020-01-03
+```
+and the table:
+
+```sql
+CREATE TABLE imp_regex_table (id UInt32, array Array(UInt32), string String, date Date) ENGINE = Memory;
+```
+
+Import command:
+
+```bash
+$ cat data.tsv | clickhouse-client  --query "INSERT INTO imp_regex_table FORMAT Regexp SETTINGS format_regexp='id: (.+?) array: (.+?) string: (.+?) date: (.+?)', format_regexp_escaping_rule='Escaped', format_regexp_skip_unmatched=0;"
+```
+
+Query:
+
+```sql
+SELECT * FROM imp_regex_table;
+```
+
+Result:
+
+```text
+┌─id─┬─array───┬─string─┬───────date─┐
+│  1 │ [1,2,3] │ str1   │ 2020-01-01 │
+│  2 │ [1,2,3] │ str2   │ 2020-01-02 │
+│  3 │ [1,2,3] │ str3   │ 2020-01-03 │
+└────┴─────────┴────────┴────────────┘
+```
+
+## Format Schema {#formatschema}
+
+The file name containing the format schema is set by the setting `format_schema`.
+It’s required to set this setting when it is used one of the formats `Cap'n Proto` and `Protobuf`.
+The format schema is a combination of a file name and the name of a message type in this file, delimited by a colon,
+e.g. `schemafile.proto:MessageType`.
+If the file has the standard extension for the format (for example, `.proto` for `Protobuf`),
+it can be omitted and in this case, the format schema looks like `schemafile:MessageType`.
+
+If you input or output data via the [client](../interfaces/cli.md) in the [interactive mode](../interfaces/cli.md#cli_usage), the file name specified in the format schema
+can contain an absolute path or a path relative to the current directory on the client.
+If you use the client in the [batch mode](../interfaces/cli.md#cli_usage), the path to the schema must be relative due to security reasons.
+
+If you input or output data via the [HTTP interface](../interfaces/http.md) the file name specified in the format schema
+should be located in the directory specified in [format_schema_path](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-format_schema_path)
+in the server configuration.
+
+## Skipping Errors {#skippingerrors}
+
+Some formats such as `CSV`, `TabSeparated`, `TSKV`, `JSONEachRow`, `Template`, `CustomSeparated` and `Protobuf` can skip broken row if parsing error occurred and continue parsing from the beginning of next row. See [input_format_allow_errors_num](../operations/settings/settings.md#settings-input_format_allow_errors_num) and
+[input_format_allow_errors_ratio](../operations/settings/settings.md#settings-input_format_allow_errors_ratio) settings.
+Limitations:
+- In case of parsing error `JSONEachRow` skips all data until the new line (or EOF), so rows must be delimited by `\n` to count errors correctly.
+- `Template` and `CustomSeparated` use delimiter after the last column and delimiter between rows to find the beginning of next row, so skipping errors works only if at least one of them is not empty.
+
+## RawBLOB {#rawblob}
+
+In this format, all input data is read to a single value. It is possible to parse only a table with a single field of type [String](../sql-reference/data-types/string.md) or similar.
+The result is output in binary format without delimiters and escaping. If more than one value is output, the format is ambiguous, and it will be impossible to read the data back.
+
+Below is a comparison of the formats `RawBLOB` and [TabSeparatedRaw](#tabseparatedraw).
+`RawBLOB`:
+- data is output in binary format, no escaping;
+- there are no delimiters between values;
+- no newline at the end of each value.
+[TabSeparatedRaw] (#tabseparatedraw):
+- data is output without escaping;
+- the rows contain values separated by tabs;
+- there is a line feed after the last value in every row.
+
+The following is a comparison of the `RawBLOB` and [RowBinary](#rowbinary) formats.
+`RawBLOB`:
+- String fields are output without being prefixed by length.
+`RowBinary`:
+- String fields are represented as length in varint format (unsigned [LEB128] (https://en.wikipedia.org/wiki/LEB128)), followed by the bytes of the string.
+
+When an empty data is passed to the `RawBLOB` input, ClickHouse throws an exception:
+
+``` text
+Code: 108. DB::Exception: No data to insert
+```
+
+**Example**
+
+``` bash
+$ clickhouse-client --query "CREATE TABLE {some_table} (a String) ENGINE = Memory;"
+$ cat {filename} | clickhouse-client --query="INSERT INTO {some_table} FORMAT RawBLOB"
+$ clickhouse-client --query "SELECT * FROM {some_table} FORMAT RawBLOB" | md5sum
+```
+
+Result:
+
+``` text
+f9725a22f9191e064120d718e26862a9  -
+```
+
+## MsgPack {#msgpack}
+
+ClickHouse supports reading and writing [MessagePack](https://msgpack.org/) data files.
+
+### Data Types Matching {#data-types-matching-msgpack}
+
+| MessagePack data type (`INSERT`)                                   | ClickHouse data type                                      | MessagePack data type (`SELECT`)   |
+|--------------------------------------------------------------------|-----------------------------------------------------------|------------------------------------|
+| `uint N`, `positive fixint`                                        | [UIntN](../sql-reference/data-types/int-uint.md)          | `uint N`                           |
+| `int N`                                                            | [IntN](../sql-reference/data-types/int-uint.md)           | `int N`                            |
+| `bool`                                                             | [UInt8](../sql-reference/data-types/int-uint.md)          | `uint 8`                           |
+| `fixstr`, `str 8`, `str 16`, `str 32`, `bin 8`, `bin 16`, `bin 32` | [String](../sql-reference/data-types/string.md)           | `bin 8`, `bin 16`, `bin 32`        |
+| `fixstr`, `str 8`, `str 16`, `str 32`, `bin 8`, `bin 16`, `bin 32` | [FixedString](../sql-reference/data-types/fixedstring.md) | `bin 8`, `bin 16`, `bin 32`        |
+| `float 32`                                                         | [Float32](../sql-reference/data-types/float.md)           | `float 32`                         |
+| `float 64`                                                         | [Float64](../sql-reference/data-types/float.md)           | `float 64`                         |
+| `uint 16`                                                          | [Date](../sql-reference/data-types/date.md)               | `uint 16`                          |
+| `uint 32`                                                          | [DateTime](../sql-reference/data-types/datetime.md)       | `uint 32`                          |
+| `uint 64`                                                          | [DateTime64](../sql-reference/data-types/datetime.md)     | `uint 64`                          |
+| `fixarray`, `array 16`, `array 32`                                 | [Array](../sql-reference/data-types/array.md)             | `fixarray`, `array 16`, `array 32` |
+| `fixmap`, `map 16`, `map 32`                                       | [Map](../sql-reference/data-types/map.md)                 | `fixmap`, `map 16`, `map 32`       |
+
+Example:
+
+Writing to a file ".msgpk":
+
+```sql
+$ clickhouse-client --query="CREATE TABLE msgpack (array Array(UInt8)) ENGINE = Memory;"
+$ clickhouse-client --query="INSERT INTO msgpack VALUES ([0, 1, 2, 3, 42, 253, 254, 255]), ([255, 254, 253, 42, 3, 2, 1, 0])";
+$ clickhouse-client --query="SELECT * FROM msgpack FORMAT MsgPack" > tmp_msgpack.msgpk;
+```
diff --git a/docs/en/reference/interfaces/grpc.md b/docs/en/reference/interfaces/grpc.md
new file mode 100644
index 00000000000..6ada38c6220
--- /dev/null
+++ b/docs/en/reference/interfaces/grpc.md
@@ -0,0 +1,99 @@
+---
+sidebar_position: 19
+sidebar_label: gRPC Interface
+---
+
+# gRPC Interface {#grpc-interface}
+
+## Introduction {#grpc-interface-introduction}
+
+ClickHouse supports [gRPC](https://grpc.io/) interface. It is an open source remote procedure call system that uses HTTP/2 and [Protocol Buffers](https://en.wikipedia.org/wiki/Protocol_Buffers). The implementation of gRPC in ClickHouse supports:
+
+-   SSL; 
+-   authentication; 
+-   sessions; 
+-   compression; 
+-   parallel queries through the same channel; 
+-   cancellation of queries; 
+-   getting progress and logs; 
+-   external tables.
+
+The specification of the interface is described in [clickhouse_grpc.proto](https://github.com/ClickHouse/ClickHouse/blob/master/src/Server/grpc_protos/clickhouse_grpc.proto).
+
+## gRPC Configuration {#grpc-interface-configuration}
+
+To use the gRPC interface set `grpc_port` in the main [server configuration](../operations/configuration-files.md). Other configuration options see in the following example:
+
+```xml
+<grpc_port>9100</grpc_port>
+    <grpc>
+        <enable_ssl>false</enable_ssl>
+
+        <!-- The following two files are used only if SSL is enabled -->
+        <ssl_cert_file>/path/to/ssl_cert_file</ssl_cert_file>
+        <ssl_key_file>/path/to/ssl_key_file</ssl_key_file>
+
+        <!-- Whether server requests client for a certificate -->
+        <ssl_require_client_auth>false</ssl_require_client_auth>
+
+        <!-- The following file is used only if ssl_require_client_auth=true -->
+        <ssl_ca_cert_file>/path/to/ssl_ca_cert_file</ssl_ca_cert_file>
+
+        <!-- Default compression algorithm (applied if client doesn't specify another algorithm, see result_compression in QueryInfo).
+             Supported algorithms: none, deflate, gzip, stream_gzip -->
+        <compression>deflate</compression>
+
+        <!-- Default compression level (applied if client doesn't specify another level, see result_compression in QueryInfo).
+             Supported levels: none, low, medium, high -->
+        <compression_level>medium</compression_level>
+
+        <!-- Send/receive message size limits in bytes. -1 means unlimited -->
+        <max_send_message_size>-1</max_send_message_size>
+        <max_receive_message_size>-1</max_receive_message_size>
+
+        <!-- Enable if you want to get detailed logs -->
+        <verbose_logs>false</verbose_logs>
+    </grpc>
+```
+
+## Built-in Client {#grpc-client}
+
+You can write a client in any of the programming languages supported by gRPC using the provided [specification](https://github.com/ClickHouse/ClickHouse/blob/master/src/Server/grpc_protos/clickhouse_grpc.proto).
+Or you can use a built-in Python client. It is placed in [utils/grpc-client/clickhouse-grpc-client.py](https://github.com/ClickHouse/ClickHouse/blob/master/utils/grpc-client/clickhouse-grpc-client.py) in the repository. The built-in client requires [grpcio and grpcio-tools](https://grpc.io/docs/languages/python/quickstart) Python modules. 
+
+The client supports the following arguments:
+
+-   `--help` – Shows a help message and exits.
+-   `--host HOST, -h HOST` – A server name. Default value: `localhost`. You can use IPv4 or IPv6 addresses also.
+-   `--port PORT` – A port to connect to. This port should be enabled in the ClickHouse server configuration (see `grpc_port`). Default value: `9100`.
+-   `--user USER_NAME, -u USER_NAME` – A user name. Default value: `default`.
+-   `--password PASSWORD` – A password. Default value: empty string.
+-   `--query QUERY, -q QUERY` – A query to process when using non-interactive mode.
+-   `--database DATABASE, -d DATABASE` – A default database. If not specified, the current database set in the server settings is used (`default` by default).
+-   `--format OUTPUT_FORMAT, -f OUTPUT_FORMAT` – A result output [format](formats.md). Default value for interactive mode: `PrettyCompact`.
+-   `--debug` – Enables showing debug information.
+
+To run the client in an interactive mode call it without `--query` argument.
+
+In a batch mode query data can be passed via `stdin`.
+
+**Client Usage Example**
+
+In the following example a table is created and loaded with data from a CSV file. Then the content of the table is queried.
+
+``` bash
+./clickhouse-grpc-client.py -q "CREATE TABLE grpc_example_table (id UInt32, text String) ENGINE = MergeTree() ORDER BY id;"
+echo "0,Input data for" > a.txt ; echo "1,gRPC protocol example" >> a.txt
+cat a.txt | ./clickhouse-grpc-client.py -q "INSERT INTO grpc_example_table FORMAT CSV"
+
+./clickhouse-grpc-client.py --format PrettyCompact -q "SELECT * FROM grpc_example_table;"
+```
+
+Result:
+
+``` text
+┌─id─┬─text──────────────────┐
+│  0 │ Input data for        │
+│  1 │ gRPC protocol example │
+└────┴───────────────────────┘
+```
diff --git a/docs/en/reference/interfaces/http.md b/docs/en/reference/interfaces/http.md
new file mode 100644
index 00000000000..a97cf6671b2
--- /dev/null
+++ b/docs/en/reference/interfaces/http.md
@@ -0,0 +1,664 @@
+---
+sidebar_position: 19
+sidebar_label: HTTP Interface
+---
+
+# HTTP Interface {#http-interface}
+
+The HTTP interface lets you use ClickHouse on any platform from any programming language. We use it for working from Java and Perl, as well as shell scripts. In other departments, the HTTP interface is used from Perl, Python, and Go. The HTTP interface is more limited than the native interface, but it has better compatibility.
+
+By default, `clickhouse-server` listens for HTTP on port 8123 (this can be changed in the config).
+
+Sometimes, `curl` command is not available on user operating systems. On Ubuntu or Debian, run `sudo apt install curl`. Please refer this [documentation](https://curl.se/download.html) to install it before running the examples.
+
+If you make a `GET /` request without parameters, it returns 200 response code and the string which defined in [http_server_default_response](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-http_server_default_response) default value “Ok.” (with a line feed at the end)
+
+``` bash
+$ curl 'http://localhost:8123/'
+Ok.
+```
+
+Web UI can be accessed here: `http://localhost:8123/play`.
+
+![Web UI](../images/play.png)
+
+
+In health-check scripts use `GET /ping` request. This handler always returns “Ok.” (with a line feed at the end). Available from version 18.12.13. See also `/replicas_status` to check replica's delay.
+
+``` bash
+$ curl 'http://localhost:8123/ping'
+Ok.
+$ curl 'http://localhost:8123/replicas_status'
+Ok.
+```
+
+Send the request as a URL ‘query’ parameter, or as a POST. Or send the beginning of the query in the ‘query’ parameter, and the rest in the POST (we’ll explain later why this is necessary). The size of the URL is limited to 16 KB, so keep this in mind when sending large queries.
+
+If successful, you receive the 200 response code and the result in the response body.
+If an error occurs, you receive the 500 response code and an error description text in the response body.
+
+When using the GET method, ‘readonly’ is set. In other words, for queries that modify data, you can only use the POST method. You can send the query itself either in the POST body or in the URL parameter.
+
+Examples:
+
+``` bash
+$ curl 'http://localhost:8123/?query=SELECT%201'
+1
+
+$ wget -nv -O- 'http://localhost:8123/?query=SELECT 1'
+1
+
+$ echo -ne 'GET /?query=SELECT%201 HTTP/1.0\r\n\r\n' | nc localhost 8123
+HTTP/1.0 200 OK
+Date: Wed, 27 Nov 2019 10:30:18 GMT
+Connection: Close
+Content-Type: text/tab-separated-values; charset=UTF-8
+X-ClickHouse-Server-Display-Name: clickhouse.ru-central1.internal
+X-ClickHouse-Query-Id: 5abe861c-239c-467f-b955-8a201abb8b7f
+X-ClickHouse-Summary: {"read_rows":"0","read_bytes":"0","written_rows":"0","written_bytes":"0","total_rows_to_read":"0"}
+
+1
+```
+
+As you can see, `curl` is somewhat inconvenient in that spaces must be URL escaped.
+Although `wget` escapes everything itself, we do not recommend using it because it does not work well over HTTP 1.1 when using keep-alive and Transfer-Encoding: chunked.
+
+``` bash
+$ echo 'SELECT 1' | curl 'http://localhost:8123/' --data-binary @-
+1
+
+$ echo 'SELECT 1' | curl 'http://localhost:8123/?query=' --data-binary @-
+1
+
+$ echo '1' | curl 'http://localhost:8123/?query=SELECT' --data-binary @-
+1
+```
+
+If part of the query is sent in the parameter, and part in the POST, a line feed is inserted between these two data parts.
+Example (this won’t work):
+
+``` bash
+$ echo 'ECT 1' | curl 'http://localhost:8123/?query=SEL' --data-binary @-
+Code: 59, e.displayText() = DB::Exception: Syntax error: failed at position 0: SEL
+ECT 1
+, expected One of: SHOW TABLES, SHOW DATABASES, SELECT, INSERT, CREATE, ATTACH, RENAME, DROP, DETACH, USE, SET, OPTIMIZE., e.what() = DB::Exception
+```
+
+By default, data is returned in [TabSeparated](formats.md#tabseparated) format.
+
+You use the FORMAT clause of the query to request any other format.
+
+Also, you can use the ‘default_format’ URL parameter or the ‘X-ClickHouse-Format’ header to specify a default format other than TabSeparated.
+
+``` bash
+$ echo 'SELECT 1 FORMAT Pretty' | curl 'http://localhost:8123/?' --data-binary @-
+┏━━━┓
+┃ 1 ┃
+┡━━━┩
+│ 1 │
+└───┘
+```
+
+The POST method of transmitting data is necessary for `INSERT` queries. In this case, you can write the beginning of the query in the URL parameter, and use POST to pass the data to insert. The data to insert could be, for example, a tab-separated dump from MySQL. In this way, the `INSERT` query replaces `LOAD DATA LOCAL INFILE` from MySQL.
+
+**Examples**
+
+Creating a table:
+
+``` bash
+$ echo 'CREATE TABLE t (a UInt8) ENGINE = Memory' | curl 'http://localhost:8123/' --data-binary @-
+```
+
+Using the familiar INSERT query for data insertion:
+
+``` bash
+$ echo 'INSERT INTO t VALUES (1),(2),(3)' | curl 'http://localhost:8123/' --data-binary @-
+```
+
+Data can be sent separately from the query:
+
+``` bash
+$ echo '(4),(5),(6)' | curl 'http://localhost:8123/?query=INSERT%20INTO%20t%20VALUES' --data-binary @-
+```
+
+You can specify any data format. The ‘Values’ format is the same as what is used when writing INSERT INTO t VALUES:
+
+``` bash
+$ echo '(7),(8),(9)' | curl 'http://localhost:8123/?query=INSERT%20INTO%20t%20FORMAT%20Values' --data-binary @-
+```
+
+To insert data from a tab-separated dump, specify the corresponding format:
+
+``` bash
+$ echo -ne '10\n11\n12\n' | curl 'http://localhost:8123/?query=INSERT%20INTO%20t%20FORMAT%20TabSeparated' --data-binary @-
+```
+
+Reading the table contents. Data is output in random order due to parallel query processing:
+
+``` bash
+$ curl 'http://localhost:8123/?query=SELECT%20a%20FROM%20t'
+7
+8
+9
+10
+11
+12
+1
+2
+3
+4
+5
+6
+```
+
+Deleting the table.
+
+``` bash
+$ echo 'DROP TABLE t' | curl 'http://localhost:8123/' --data-binary @-
+```
+
+For successful requests that do not return a data table, an empty response body is returned.
+
+
+## Compression {#compression}
+
+You can use compression to reduce network traffic when transmitting a large amount of data or for creating dumps that are immediately compressed.
+
+You can use the internal ClickHouse compression format when transmitting data. The compressed data has a non-standard format, and you need `clickhouse-compressor` program to work with it. It is installed with the `clickhouse-client` package. To increase the efficiency of data insertion, you can disable server-side checksum verification by using the [http_native_compression_disable_checksumming_on_decompress](../operations/settings/settings.md#settings-http_native_compression_disable_checksumming_on_decompress) setting.
+
+If you specify `compress=1` in the URL, the server will compress the data it sends to you. If you specify `decompress=1` in the URL, the server will decompress the data which you pass in the `POST` method.
+
+You can also choose to use [HTTP compression](https://en.wikipedia.org/wiki/HTTP_compression). ClickHouse supports the following [compression methods](https://en.wikipedia.org/wiki/HTTP_compression#Content-Encoding_tokens):
+
+- `gzip`
+- `br`
+- `deflate`
+- `xz`
+
+To send a compressed `POST` request, append the request header `Content-Encoding: compression_method`.
+In order for ClickHouse to compress the response, enable compression with [enable_http_compression](../operations/settings/settings.md#settings-enable_http_compression) setting and append `Accept-Encoding: compression_method` header to the request. You can configure the data compression level in the [http_zlib_compression_level](../operations/settings/settings.md#settings-http_zlib_compression_level) setting for all compression methods.
+
+:::info    
+Some HTTP clients might decompress data from the server by default (with `gzip` and `deflate`) and you might get decompressed data even if you use the compression settings correctly.
+:::
+
+**Examples**
+
+``` bash
+# Sending compressed data to the server
+$ echo "SELECT 1" | gzip -c | \
+  curl -sS --data-binary @- -H 'Content-Encoding: gzip' 'http://localhost:8123/'
+```
+
+``` bash
+# Receiving compressed data archive from the server
+$ curl -vsS "http://localhost:8123/?enable_http_compression=1" \
+    -H 'Accept-Encoding: gzip' --output result.gz -d 'SELECT number FROM system.numbers LIMIT 3'
+$ zcat result.gz
+0
+1
+2
+```
+
+```bash
+# Receiving compressed data from the server and using the gunzip to receive decompressed data
+$ curl -sS "http://localhost:8123/?enable_http_compression=1" \
+    -H 'Accept-Encoding: gzip' -d 'SELECT number FROM system.numbers LIMIT 3' | gunzip -
+0
+1
+2
+```
+
+## Default Database {#default-database}
+
+You can use the ‘database’ URL parameter or the ‘X-ClickHouse-Database’ header to specify the default database.
+
+``` bash
+$ echo 'SELECT number FROM numbers LIMIT 10' | curl 'http://localhost:8123/?database=system' --data-binary @-
+0
+1
+2
+3
+4
+5
+6
+7
+8
+9
+```
+
+By default, the database that is registered in the server settings is used as the default database. By default, this is the database called ‘default’. Alternatively, you can always specify the database using a dot before the table name.
+
+The username and password can be indicated in one of three ways:
+
+1.  Using HTTP Basic Authentication. Example:
+
+<!-- -->
+
+``` bash
+$ echo 'SELECT 1' | curl 'http://user:password@localhost:8123/' -d @-
+```
+
+1.  In the ‘user’ and ‘password’ URL parameters. Example:
+
+<!-- -->
+
+``` bash
+$ echo 'SELECT 1' | curl 'http://localhost:8123/?user=user&password=password' -d @-
+```
+
+1.  Using ‘X-ClickHouse-User’ and ‘X-ClickHouse-Key’ headers. Example:
+
+<!-- -->
+
+``` bash
+$ echo 'SELECT 1' | curl -H 'X-ClickHouse-User: user' -H 'X-ClickHouse-Key: password' 'http://localhost:8123/' -d @-
+```
+
+If the user name is not specified, the `default` name is used. If the password is not specified, the empty password is used.
+You can also use the URL parameters to specify any settings for processing a single query or entire profiles of settings. Example:http://localhost:8123/?profile=web&max_rows_to_read=1000000000&query=SELECT+1
+
+For more information, see the [Settings](../operations/settings/index.md) section.
+
+``` bash
+$ echo 'SELECT number FROM system.numbers LIMIT 10' | curl 'http://localhost:8123/?' --data-binary @-
+0
+1
+2
+3
+4
+5
+6
+7
+8
+9
+```
+
+For information about other parameters, see the section “SET”.
+
+Similarly, you can use ClickHouse sessions in the HTTP protocol. To do this, you need to add the `session_id` GET parameter to the request. You can use any string as the session ID. By default, the session is terminated after 60 seconds of inactivity. To change this timeout, modify the `default_session_timeout` setting in the server configuration, or add the `session_timeout` GET parameter to the request. To check the session status, use the `session_check=1` parameter. Only one query at a time can be executed within a single session.
+
+You can receive information about the progress of a query in `X-ClickHouse-Progress` response headers. To do this, enable [send_progress_in_http_headers](../operations/settings/settings.md#settings-send_progress_in_http_headers). Example of the header sequence:
+
+``` text
+X-ClickHouse-Progress: {"read_rows":"2752512","read_bytes":"240570816","total_rows_to_read":"8880128"}
+X-ClickHouse-Progress: {"read_rows":"5439488","read_bytes":"482285394","total_rows_to_read":"8880128"}
+X-ClickHouse-Progress: {"read_rows":"8783786","read_bytes":"819092887","total_rows_to_read":"8880128"}
+```
+
+Possible header fields:
+
+-   `read_rows` — Number of rows read.
+-   `read_bytes` — Volume of data read in bytes.
+-   `total_rows_to_read` — Total number of rows to be read.
+-   `written_rows` — Number of rows written.
+-   `written_bytes` — Volume of data written in bytes.
+
+Running requests do not stop automatically if the HTTP connection is lost. Parsing and data formatting are performed on the server-side, and using the network might be ineffective.
+The optional ‘query_id’ parameter can be passed as the query ID (any string). For more information, see the section “Settings, replace_running_query”.
+
+The optional ‘quota_key’ parameter can be passed as the quota key (any string). For more information, see the section “Quotas”.
+
+The HTTP interface allows passing external data (external temporary tables) for querying. For more information, see the section “External data for query processing”.
+
+## Response Buffering {#response-buffering}
+
+You can enable response buffering on the server-side. The `buffer_size` and `wait_end_of_query` URL parameters are provided for this purpose.
+
+`buffer_size` determines the number of bytes in the result to buffer in the server memory. If a result body is larger than this threshold, the buffer is written to the HTTP channel, and the remaining data is sent directly to the HTTP channel.
+
+To ensure that the entire response is buffered, set `wait_end_of_query=1`. In this case, the data that is not stored in memory will be buffered in a temporary server file.
+
+Example:
+
+``` bash
+$ curl -sS 'http://localhost:8123/?max_result_bytes=4000000&buffer_size=3000000&wait_end_of_query=1' -d 'SELECT toUInt8(number) FROM system.numbers LIMIT 9000000 FORMAT RowBinary'
+```
+
+Use buffering to avoid situations where a query processing error occurred after the response code and HTTP headers were sent to the client. In this situation, an error message is written at the end of the response body, and on the client-side, the error can only be detected at the parsing stage.
+
+### Queries with Parameters {#cli-queries-with-parameters}
+
+You can create a query with parameters and pass values for them from the corresponding HTTP request parameters. For more information, see [Queries with Parameters for CLI](../interfaces/cli.md#cli-queries-with-parameters).
+
+### Example {#example}
+
+``` bash
+$ curl -sS "<address>?param_id=2&param_phrase=test" -d "SELECT * FROM table WHERE int_column = {id:UInt8} and string_column = {phrase:String}"
+```
+
+## Predefined HTTP Interface {#predefined_http_interface}
+
+ClickHouse supports specific queries through the HTTP interface. For example, you can write data to a table as follows:
+
+``` bash
+$ echo '(4),(5),(6)' | curl 'http://localhost:8123/?query=INSERT%20INTO%20t%20VALUES' --data-binary @-
+```
+
+ClickHouse also supports Predefined HTTP Interface which can help you more easily integrate with third-party tools like [Prometheus exporter](https://github.com/percona-lab/clickhouse_exporter).
+
+Example:
+
+-   First of all, add this section to server configuration file:
+
+<!-- -->
+
+``` xml
+<http_handlers>
+    <rule>
+        <url>/predefined_query</url>
+        <methods>POST,GET</methods>
+        <handler>
+            <type>predefined_query_handler</type>
+            <query>SELECT * FROM system.metrics LIMIT 5 FORMAT Template SETTINGS format_template_resultset = 'prometheus_template_output_format_resultset', format_template_row = 'prometheus_template_output_format_row', format_template_rows_between_delimiter = '\n'</query>
+        </handler>
+    </rule>
+    <rule>...</rule>
+    <rule>...</rule>
+</http_handlers>
+```
+
+-   You can now request the URL directly for data in the Prometheus format:
+
+<!-- -->
+
+``` bash
+$ curl -v 'http://localhost:8123/predefined_query'
+*   Trying ::1...
+* Connected to localhost (::1) port 8123 (#0)
+> GET /predefined_query HTTP/1.1
+> Host: localhost:8123
+> User-Agent: curl/7.47.0
+> Accept: */*
+>
+< HTTP/1.1 200 OK
+< Date: Tue, 28 Apr 2020 08:52:56 GMT
+< Connection: Keep-Alive
+< Content-Type: text/plain; charset=UTF-8
+< X-ClickHouse-Server-Display-Name: i-mloy5trc
+< Transfer-Encoding: chunked
+< X-ClickHouse-Query-Id: 96fe0052-01e6-43ce-b12a-6b7370de6e8a
+< X-ClickHouse-Format: Template
+< X-ClickHouse-Timezone: Asia/Shanghai
+< Keep-Alive: timeout=3
+< X-ClickHouse-Summary: {"read_rows":"0","read_bytes":"0","written_rows":"0","written_bytes":"0","total_rows_to_read":"0"}
+<
+# HELP "Query" "Number of executing queries"
+# TYPE "Query" counter
+"Query" 1
+
+# HELP "Merge" "Number of executing background merges"
+# TYPE "Merge" counter
+"Merge" 0
+
+# HELP "PartMutation" "Number of mutations (ALTER DELETE/UPDATE)"
+# TYPE "PartMutation" counter
+"PartMutation" 0
+
+# HELP "ReplicatedFetch" "Number of data parts being fetched from replica"
+# TYPE "ReplicatedFetch" counter
+"ReplicatedFetch" 0
+
+# HELP "ReplicatedSend" "Number of data parts being sent to replicas"
+# TYPE "ReplicatedSend" counter
+"ReplicatedSend" 0
+
+* Connection #0 to host localhost left intact
+
+* Connection #0 to host localhost left intact
+```
+
+As you can see from the example if `http_handlers` is configured in the config.xml file and `http_handlers` can contain many `rules`. ClickHouse will match the HTTP requests received to the predefined type in `rule` and the first matched runs the handler. Then ClickHouse will execute the corresponding predefined query if the match is successful.
+
+Now `rule` can configure `method`, `headers`, `url`, `handler`:
+- `method` is responsible for matching the method part of the HTTP request. `method` fully conforms to the definition of [method](https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods) in the HTTP protocol. It is an optional configuration. If it is not defined in the configuration file, it does not match the method portion of the HTTP request.
+
+-   `url` is responsible for matching the URL part of the HTTP request. It is compatible with [RE2](https://github.com/google/re2)’s regular expressions. It is an optional configuration. If it is not defined in the configuration file, it does not match the URL portion of the HTTP request.
+
+-   `headers` are responsible for matching the header part of the HTTP request. It is compatible with RE2’s regular expressions. It is an optional configuration. If it is not defined in the configuration file, it does not match the header portion of the HTTP request.
+
+-   `handler` contains the main processing part. Now `handler` can configure `type`, `status`, `content_type`, `response_content`, `query`, `query_param_name`.
+    `type` currently supports three types: [predefined_query_handler](#predefined_query_handler), [dynamic_query_handler](#dynamic_query_handler), [static](#static).
+
+    -   `query` — use with `predefined_query_handler` type, executes query when the handler is called.
+
+    -   `query_param_name` — use with `dynamic_query_handler` type, extracts and executes the value corresponding to the `query_param_name` value in HTTP request params.
+
+    -   `status` — use with `static` type, response status code.
+
+    -   `content_type` — use with `static` type, response [content-type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type).
+
+    -   `response_content` — use with `static` type, response content sent to client, when using the prefix ‘file://’ or ‘config://’, find the content from the file or configuration sends to client.
+
+Next are the configuration methods for different `type`.
+
+### predefined_query_handler {#predefined_query_handler}
+
+`predefined_query_handler` supports setting `Settings` and `query_params` values. You can configure `query` in the type of `predefined_query_handler`.
+
+`query` value is a predefined query of `predefined_query_handler`, which is executed by ClickHouse when an HTTP request is matched and the result of the query is returned. It is a must configuration.
+
+The following example defines the values of [max_threads](../operations/settings/settings.md#settings-max_threads) and `max_final_threads` settings, then queries the system table to check whether these settings were set successfully.
+
+:::warning
+To keep the default `handlers` such as` query`, `play`,` ping`, add the `<defaults/>` rule.
+:::
+
+Example:
+
+``` xml
+<http_handlers>
+    <rule>
+        <url><![CDATA[/query_param_with_url/\w+/(?P<name_1>[^/]+)(/(?P<name_2>[^/]+))?]]></url>
+        <methods>GET</methods>
+        <headers>
+            <XXX>TEST_HEADER_VALUE</XXX>
+            <PARAMS_XXX><![CDATA[(?P<name_1>[^/]+)(/(?P<name_2>[^/]+))?]]></PARAMS_XXX>
+        </headers>
+        <handler>
+            <type>predefined_query_handler</type>
+            <query>SELECT value FROM system.settings WHERE name = {name_1:String}</query>
+            <query>SELECT name, value FROM system.settings WHERE name = {name_2:String}</query>
+        </handler>
+    </rule>
+    <defaults/>
+</http_handlers>
+```
+
+``` bash
+$ curl -H 'XXX:TEST_HEADER_VALUE' -H 'PARAMS_XXX:max_threads' 'http://localhost:8123/query_param_with_url/1/max_threads/max_final_threads?max_threads=1&max_final_threads=2'
+1
+max_final_threads   2
+```
+
+:::warning
+In one `predefined_query_handler` only supports one `query` of an insert type.
+:::
+
+### dynamic_query_handler {#dynamic_query_handler}
+
+In `dynamic_query_handler`, the query is written in the form of param of the HTTP request. The difference is that in `predefined_query_handler`, the query is written in the configuration file. You can configure `query_param_name` in `dynamic_query_handler`.
+
+ClickHouse extracts and executes the value corresponding to the `query_param_name` value in the URL of the HTTP request. The default value of `query_param_name` is `/query` . It is an optional configuration. If there is no definition in the configuration file, the param is not passed in.
+
+To experiment with this functionality, the example defines the values of [max_threads](../operations/settings/settings.md#settings-max_threads) and `max_final_threads` and `queries` whether the settings were set successfully.
+
+Example:
+
+``` xml
+<http_handlers>
+    <rule>
+    <headers>
+        <XXX>TEST_HEADER_VALUE_DYNAMIC</XXX>    </headers>
+    <handler>
+        <type>dynamic_query_handler</type>
+        <query_param_name>query_param</query_param_name>
+    </handler>
+    </rule>
+    <defaults/>
+</http_handlers>
+```
+
+``` bash
+$ curl  -H 'XXX:TEST_HEADER_VALUE_DYNAMIC'  'http://localhost:8123/own?max_threads=1&max_final_threads=2&param_name_1=max_threads&param_name_2=max_final_threads&query_param=SELECT%20name,value%20FROM%20system.settings%20where%20name%20=%20%7Bname_1:String%7D%20OR%20name%20=%20%7Bname_2:String%7D'
+max_threads 1
+max_final_threads   2
+```
+
+### static {#static}
+
+`static` can return [content_type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type), [status](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status) and `response_content`. `response_content` can return the specified content.
+
+Example:
+
+Return a message.
+
+``` xml
+<http_handlers>
+        <rule>
+            <methods>GET</methods>
+            <headers><XXX>xxx</XXX></headers>
+            <url>/hi</url>
+            <handler>
+                <type>static</type>
+                <status>402</status>
+                <content_type>text/html; charset=UTF-8</content_type>
+                <response_content>Say Hi!</response_content>
+            </handler>
+        </rule>
+        <defaults/>
+</http_handlers>
+```
+
+``` bash
+$ curl -vv  -H 'XXX:xxx' 'http://localhost:8123/hi'
+*   Trying ::1...
+* Connected to localhost (::1) port 8123 (#0)
+> GET /hi HTTP/1.1
+> Host: localhost:8123
+> User-Agent: curl/7.47.0
+> Accept: */*
+> XXX:xxx
+>
+< HTTP/1.1 402 Payment Required
+< Date: Wed, 29 Apr 2020 03:51:26 GMT
+< Connection: Keep-Alive
+< Content-Type: text/html; charset=UTF-8
+< Transfer-Encoding: chunked
+< Keep-Alive: timeout=3
+< X-ClickHouse-Summary: {"read_rows":"0","read_bytes":"0","written_rows":"0","written_bytes":"0","total_rows_to_read":"0"}
+<
+* Connection #0 to host localhost left intact
+Say Hi!%
+```
+
+Find the content from the configuration send to client.
+
+``` xml
+<get_config_static_handler><![CDATA[<html ng-app="SMI2"><head><base href="http://ui.tabix.io/"></head><body><div ui-view="" class="content-ui"></div><script src="http://loader.tabix.io/master.js"></script></body></html>]]></get_config_static_handler>
+
+<http_handlers>
+        <rule>
+            <methods>GET</methods>
+            <headers><XXX>xxx</XXX></headers>
+            <url>/get_config_static_handler</url>
+            <handler>
+                <type>static</type>
+                <response_content>config://get_config_static_handler</response_content>
+            </handler>
+        </rule>
+</http_handlers>
+```
+
+``` bash
+$ curl -v  -H 'XXX:xxx' 'http://localhost:8123/get_config_static_handler'
+*   Trying ::1...
+* Connected to localhost (::1) port 8123 (#0)
+> GET /get_config_static_handler HTTP/1.1
+> Host: localhost:8123
+> User-Agent: curl/7.47.0
+> Accept: */*
+> XXX:xxx
+>
+< HTTP/1.1 200 OK
+< Date: Wed, 29 Apr 2020 04:01:24 GMT
+< Connection: Keep-Alive
+< Content-Type: text/plain; charset=UTF-8
+< Transfer-Encoding: chunked
+< Keep-Alive: timeout=3
+< X-ClickHouse-Summary: {"read_rows":"0","read_bytes":"0","written_rows":"0","written_bytes":"0","total_rows_to_read":"0"}
+<
+* Connection #0 to host localhost left intact
+<html ng-app="SMI2"><head><base href="http://ui.tabix.io/"></head><body><div ui-view="" class="content-ui"></div><script src="http://loader.tabix.io/master.js"></script></body></html>%
+```
+
+Find the content from the file send to client.
+
+``` xml
+<http_handlers>
+        <rule>
+            <methods>GET</methods>
+            <headers><XXX>xxx</XXX></headers>
+            <url>/get_absolute_path_static_handler</url>
+            <handler>
+                <type>static</type>
+                <content_type>text/html; charset=UTF-8</content_type>
+                <response_content>file:///absolute_path_file.html</response_content>
+            </handler>
+        </rule>
+        <rule>
+            <methods>GET</methods>
+            <headers><XXX>xxx</XXX></headers>
+            <url>/get_relative_path_static_handler</url>
+            <handler>
+                <type>static</type>
+                <content_type>text/html; charset=UTF-8</content_type>
+                <response_content>file://./relative_path_file.html</response_content>
+            </handler>
+        </rule>
+</http_handlers>
+```
+
+``` bash
+$ user_files_path='/var/lib/clickhouse/user_files'
+$ sudo echo "<html><body>Relative Path File</body></html>" > $user_files_path/relative_path_file.html
+$ sudo echo "<html><body>Absolute Path File</body></html>" > $user_files_path/absolute_path_file.html
+$ curl -vv -H 'XXX:xxx' 'http://localhost:8123/get_absolute_path_static_handler'
+*   Trying ::1...
+* Connected to localhost (::1) port 8123 (#0)
+> GET /get_absolute_path_static_handler HTTP/1.1
+> Host: localhost:8123
+> User-Agent: curl/7.47.0
+> Accept: */*
+> XXX:xxx
+>
+< HTTP/1.1 200 OK
+< Date: Wed, 29 Apr 2020 04:18:16 GMT
+< Connection: Keep-Alive
+< Content-Type: text/html; charset=UTF-8
+< Transfer-Encoding: chunked
+< Keep-Alive: timeout=3
+< X-ClickHouse-Summary: {"read_rows":"0","read_bytes":"0","written_rows":"0","written_bytes":"0","total_rows_to_read":"0"}
+<
+<html><body>Absolute Path File</body></html>
+* Connection #0 to host localhost left intact
+$ curl -vv -H 'XXX:xxx' 'http://localhost:8123/get_relative_path_static_handler'
+*   Trying ::1...
+* Connected to localhost (::1) port 8123 (#0)
+> GET /get_relative_path_static_handler HTTP/1.1
+> Host: localhost:8123
+> User-Agent: curl/7.47.0
+> Accept: */*
+> XXX:xxx
+>
+< HTTP/1.1 200 OK
+< Date: Wed, 29 Apr 2020 04:18:31 GMT
+< Connection: Keep-Alive
+< Content-Type: text/html; charset=UTF-8
+< Transfer-Encoding: chunked
+< Keep-Alive: timeout=3
+< X-ClickHouse-Summary: {"read_rows":"0","read_bytes":"0","written_rows":"0","written_bytes":"0","total_rows_to_read":"0"}
+<
+<html><body>Relative Path File</body></html>
+* Connection #0 to host localhost left intact
+```
diff --git a/docs/en/reference/interfaces/index.md b/docs/en/reference/interfaces/index.md
new file mode 100644
index 00000000000..16e97ed7c62
--- /dev/null
+++ b/docs/en/reference/interfaces/index.md
@@ -0,0 +1,28 @@
+---
+sidebar_label: Interfaces
+sidebar_position: 34
+keywords: [clickhouse, network, interfaces, http, tcp, grpc, command-line, client, jdbc, odbc, driver]
+description: ClickHouse provides three network interfaces
+---
+
+# Interfaces {#interfaces}
+
+ClickHouse provides three network interfaces (they can be optionally wrapped in TLS for additional security):
+
+-   [HTTP](http.md), which is documented and easy to use directly.
+-   [Native TCP](../interfaces/tcp.md), which has less overhead.
+-   [gRPC](grpc.md).
+
+In most cases it is recommended to use an appropriate tool or library instead of interacting with those directly. The following are officially supported by ClickHouse:
+
+-   [Command-line client](../interfaces/cli.md)
+-   [JDBC driver](../interfaces/jdbc.md)
+-   [ODBC driver](../interfaces/odbc.md)
+-   [C++ client library](../interfaces/cpp.md)
+
+There are also a wide range of third-party libraries for working with ClickHouse:
+
+-   [Client libraries](../interfaces/third-party/client-libraries.md)
+-   [Integrations](../interfaces/third-party/integrations.md)
+-   [Visual interfaces](../interfaces/third-party/gui.md)
+
diff --git a/docs/en/reference/interfaces/jdbc.md b/docs/en/reference/interfaces/jdbc.md
new file mode 100644
index 00000000000..4bea0600a2a
--- /dev/null
+++ b/docs/en/reference/interfaces/jdbc.md
@@ -0,0 +1,14 @@
+---
+sidebar_position: 22
+sidebar_label: JDBC Driver
+---
+
+# JDBC Driver {#jdbc-driver}
+
+Use the [official JDBC driver](https://github.com/ClickHouse/clickhouse-jdbc) (and Java client) to access ClickHouse from your Java applications.
+
+-   Third-party drivers:
+    -   [ClickHouse-Native-JDBC](https://github.com/housepower/ClickHouse-Native-JDBC)
+    -   [clickhouse4j](https://github.com/blynkkk/clickhouse4j)
+
+[Original article](https://clickhouse.com/docs/en/interfaces/jdbc/) <!--hide-->
diff --git a/docs/en/reference/interfaces/mysql.md b/docs/en/reference/interfaces/mysql.md
new file mode 100644
index 00000000000..df8ef38d671
--- /dev/null
+++ b/docs/en/reference/interfaces/mysql.md
@@ -0,0 +1,53 @@
+---
+sidebar_position: 20
+sidebar_label: MySQL Interface
+---
+
+# MySQL Interface {#mysql-interface}
+
+ClickHouse supports MySQL wire protocol. It can be enabled by [mysql_port](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-mysql_port) setting in configuration file:
+
+``` xml
+<mysql_port>9004</mysql_port>
+```
+
+Example of connecting using command-line tool `mysql`:
+
+``` bash
+$ mysql --protocol tcp -u default -P 9004
+```
+
+Output if a connection succeeded:
+
+``` text
+Welcome to the MySQL monitor.  Commands end with ; or \g.
+Your MySQL connection id is 4
+Server version: 20.2.1.1-ClickHouse
+
+Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
+
+Oracle is a registered trademark of Oracle Corporation and/or its
+affiliates. Other names may be trademarks of their respective
+owners.
+
+Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
+
+mysql>
+```
+
+For compatibility with all MySQL clients, it is recommended to specify user password with [double SHA1](../operations/settings/settings-users.md#password_double_sha1_hex) in configuration file.
+If user password is specified using [SHA256](../operations/settings/settings-users.md#password_sha256_hex), some clients won’t be able to authenticate (mysqljs and old versions of command-line tool MySQL and MariaDB).
+
+Restrictions:
+
+-   prepared queries are not supported
+
+-   some data types are sent as strings
+
+To cancel a long query use `KILL QUERY connection_id` statement (it is replaced with `KILL QUERY WHERE query_id = connection_id` while proceeding). For example:
+
+``` bash
+$ mysql --protocol tcp -h mysql_server -P 9004 default -u default --password=123 -e "KILL QUERY 123456;"
+```
+
+[Original article](https://clickhouse.com/docs/en/interfaces/mysql/) <!--hide-->
diff --git a/docs/en/reference/interfaces/odbc.md b/docs/en/reference/interfaces/odbc.md
new file mode 100644
index 00000000000..4c807654c28
--- /dev/null
+++ b/docs/en/reference/interfaces/odbc.md
@@ -0,0 +1,12 @@
+---
+sidebar_position: 23
+sidebar_label: ODBC Driver
+---
+
+# ODBC Driver {#odbc-driver}
+
+Use the [official ODBC driver](https://github.com/ClickHouse/clickhouse-odbc) for accessing ClickHouse as a data source.
+
+  
+
+[Original article](https://clickhouse.com/docs/en/interfaces/odbc/) <!--hide-->
diff --git a/docs/en/reference/interfaces/tcp.md b/docs/en/reference/interfaces/tcp.md
new file mode 100644
index 00000000000..5f2f400799f
--- /dev/null
+++ b/docs/en/reference/interfaces/tcp.md
@@ -0,0 +1,10 @@
+---
+sidebar_position: 18
+sidebar_label: Native Interface (TCP)
+---
+
+# Native Interface (TCP) {#native-interface-tcp}
+
+The native protocol is used in the [command-line client](../interfaces/cli.md), for inter-server communication during distributed query processing, and also in other C++ programs. Unfortunately, native ClickHouse protocol does not have formal specification yet, but it can be reverse-engineered from ClickHouse source code (starting [around here](https://github.com/ClickHouse/ClickHouse/tree/master/src/Client)) and/or by intercepting and analyzing TCP traffic.
+
+[Original article](https://clickhouse.com/docs/en/interfaces/tcp/) <!--hide-->
diff --git a/docs/en/reference/interfaces/third-party/client-libraries.md b/docs/en/reference/interfaces/third-party/client-libraries.md
new file mode 100644
index 00000000000..885e9f430f2
--- /dev/null
+++ b/docs/en/reference/interfaces/third-party/client-libraries.md
@@ -0,0 +1,74 @@
+---
+sidebar_position: 26
+sidebar_label: Client Libraries
+---
+
+# Client Libraries from Third-party Developers {#client-libraries-from-third-party-developers}
+
+:::warning    
+ClickHouse Inc does **not** maintain the libraries listed below and hasn’t done any extensive testing to ensure their quality.
+:::
+
+-   Python
+    -   [infi.clickhouse_orm](https://github.com/Infinidat/infi.clickhouse_orm)
+    -   [clickhouse-driver](https://github.com/mymarilyn/clickhouse-driver)
+    -   [clickhouse-client](https://github.com/yurial/clickhouse-client)
+    -   [aiochclient](https://github.com/maximdanilchenko/aiochclient)
+    -   [asynch](https://github.com/long2ice/asynch)
+-   PHP
+    -   [smi2/phpclickhouse](https://packagist.org/packages/smi2/phpClickHouse)
+    -   [8bitov/clickhouse-php-client](https://packagist.org/packages/8bitov/clickhouse-php-client)
+    -   [bozerkins/clickhouse-client](https://packagist.org/packages/bozerkins/clickhouse-client)
+    -   [simpod/clickhouse-client](https://packagist.org/packages/simpod/clickhouse-client)
+    -   [seva-code/php-click-house-client](https://packagist.org/packages/seva-code/php-click-house-client)
+    -   [SeasClick C++ client](https://github.com/SeasX/SeasClick)
+    -   [one-ck](https://github.com/lizhichao/one-ck)
+    -   [glushkovds/phpclickhouse-laravel](https://packagist.org/packages/glushkovds/phpclickhouse-laravel)
+    -   [kolya7k ClickHouse PHP extension](https://github.com//kolya7k/clickhouse-php)
+-   Go
+    -   [clickhouse](https://github.com/kshvakov/clickhouse/)
+    -   [go-clickhouse](https://github.com/roistat/go-clickhouse)
+    -   [chconn](https://github.com/vahid-sohrabloo/chconn)
+    -   [mailrugo-clickhouse](https://github.com/mailru/go-clickhouse)
+    -   [golang-clickhouse](https://github.com/leprosus/golang-clickhouse)
+-   Swift
+    -   [ClickHouseNIO](https://github.com/patrick-zippenfenig/ClickHouseNIO)
+    -   [ClickHouseVapor ORM](https://github.com/patrick-zippenfenig/ClickHouseVapor)
+-   NodeJs
+    -   [clickhouse (NodeJs)](https://github.com/TimonKK/clickhouse)
+    -   [node-clickhouse](https://github.com/apla/node-clickhouse)
+    -   [nestjs-clickhouse](https://github.com/depyronick/nestjs-clickhouse)
+    -   [clickhouse-client](https://github.com/depyronick/clickhouse-client)
+-   Perl
+    -   [perl-DBD-ClickHouse](https://github.com/elcamlost/perl-DBD-ClickHouse)
+    -   [HTTP-ClickHouse](https://metacpan.org/release/HTTP-ClickHouse)
+    -   [AnyEvent-ClickHouse](https://metacpan.org/release/AnyEvent-ClickHouse)
+-   Ruby
+    -   [ClickHouse (Ruby)](https://github.com/shlima/click_house)
+    -   [clickhouse-activerecord](https://github.com/PNixx/clickhouse-activerecord)
+-   Rust
+    -   [Klickhouse](https://github.com/Protryon/klickhouse)
+-   R
+    -   [clickhouse-r](https://github.com/hannesmuehleisen/clickhouse-r)
+    -   [RClickHouse](https://github.com/IMSMWU/RClickHouse)
+-   Java
+    -   [clickhouse-client-java](https://github.com/VirtusAI/clickhouse-client-java)
+    -   [clickhouse-client](https://github.com/Ecwid/clickhouse-client)
+-   Scala
+    -   [clickhouse-scala-client](https://github.com/crobox/clickhouse-scala-client)
+-   Kotlin
+    -   [AORM](https://github.com/TanVD/AORM)
+-   C#
+    -   [Octonica.ClickHouseClient](https://github.com/Octonica/ClickHouseClient)
+    -   [ClickHouse.Ado](https://github.com/killwort/ClickHouse-Net)
+    -   [ClickHouse.Client](https://github.com/DarkWanderer/ClickHouse.Client)
+    -   [ClickHouse.Net](https://github.com/ilyabreev/ClickHouse.Net)
+-   Elixir
+    -   [clickhousex](https://github.com/appodeal/clickhousex/)
+    -   [pillar](https://github.com/sofakingworld/pillar)
+-   Nim
+    -   [nim-clickhouse](https://github.com/leonardoce/nim-clickhouse)
+-   Haskell
+    -   [hdbc-clickhouse](https://github.com/zaneli/hdbc-clickhouse)
+
+[Original article](https://clickhouse.com/docs/en/interfaces/third-party/client_libraries/) <!--hide-->
diff --git a/docs/en/reference/interfaces/third-party/gui.md b/docs/en/reference/interfaces/third-party/gui.md
new file mode 100644
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+---
+sidebar_position: 28
+sidebar_label: Visual Interfaces
+---
+
+# Visual Interfaces from Third-party Developers {#visual-interfaces-from-third-party-developers}
+
+## Open-Source {#open-source}
+
+### Tabix {#tabix}
+
+Web interface for ClickHouse in the [Tabix](https://github.com/tabixio/tabix) project.
+
+Features:
+
+-   Works with ClickHouse directly from the browser, without the need to install additional software.
+-   Query editor with syntax highlighting.
+-   Auto-completion of commands.
+-   Tools for graphical analysis of query execution.
+-   Colour scheme options.
+
+[Tabix documentation](https://tabix.io/doc/).
+
+### HouseOps {#houseops}
+
+[HouseOps](https://github.com/HouseOps/HouseOps) is a UI/IDE for OSX, Linux and Windows.
+
+Features:
+
+-   Query builder with syntax highlighting. View the response in a table or JSON view.
+-   Export query results as CSV or JSON.
+-   List of processes with descriptions. Write mode. Ability to stop (`KILL`) a process.
+-   Database graph. Shows all tables and their columns with additional information.
+-   A quick view of the column size.
+-   Server configuration.
+
+The following features are planned for development:
+
+-   Database management.
+-   User management.
+-   Real-time data analysis.
+-   Cluster monitoring.
+-   Cluster management.
+-   Monitoring replicated and Kafka tables.
+
+### LightHouse {#lighthouse}
+
+[LightHouse](https://github.com/VKCOM/lighthouse) is a lightweight web interface for ClickHouse.
+
+Features:
+
+-   Table list with filtering and metadata.
+-   Table preview with filtering and sorting.
+-   Read-only queries execution.
+
+### Redash {#redash}
+
+[Redash](https://github.com/getredash/redash) is a platform for data visualization.
+
+Supports for multiple data sources including ClickHouse, Redash can join results of queries from different data sources into one final dataset.
+
+Features:
+
+-   Powerful editor of queries.
+-   Database explorer.
+-   Visualization tools, that allow you to represent data in different forms.
+
+### Grafana {#grafana}
+
+[Grafana](https://grafana.com/grafana/plugins/vertamedia-clickhouse-datasource) is a platform for monitoring and visualization.
+
+"Grafana allows you to query, visualize, alert on and understand your metrics no matter where they are stored. Create, explore, and share dashboards with your team and foster a data driven culture. Trusted and loved by the community" &mdash; grafana.com.
+
+ClickHouse datasource plugin provides a support for ClickHouse as a backend database.
+
+### DBeaver {#dbeaver}
+
+[DBeaver](https://dbeaver.io/) - universal desktop database client with ClickHouse support.
+
+Features:
+
+-   Query development with syntax highlight and autocompletion.
+-   Table list with filters and metadata search.
+-   Table data preview.
+-   Full-text search.
+
+By default, DBeaver does not connect using a session (the CLI for example does). If you require session support (for example to set settings for your session), edit the driver connection properties and set `session_id` to a random string (it uses the http connection under the hood). Then you can use any setting from the query window.
+
+### clickhouse-cli {#clickhouse-cli}
+
+[clickhouse-cli](https://github.com/hatarist/clickhouse-cli) is an alternative command-line client for ClickHouse, written in Python 3.
+
+Features:
+
+-   Autocompletion.
+-   Syntax highlighting for the queries and data output.
+-   Pager support for the data output.
+-   Custom PostgreSQL-like commands.
+
+### clickhouse-flamegraph {#clickhouse-flamegraph}
+
+[clickhouse-flamegraph](https://github.com/Slach/clickhouse-flamegraph) is a specialized tool to visualize the `system.trace_log` as [flamegraph](http://www.brendangregg.com/flamegraphs.html).
+
+### clickhouse-plantuml {#clickhouse-plantuml}
+
+[cickhouse-plantuml](https://pypi.org/project/clickhouse-plantuml/) is a script to generate [PlantUML](https://plantuml.com/) diagram of tables’ schemes.
+
+### xeus-clickhouse {#xeus-clickhouse}
+
+[xeus-clickhouse](https://github.com/wangfenjin/xeus-clickhouse) is a Jupyter kernal for ClickHouse, which supports query CH data using SQL in Jupyter.
+
+### MindsDB Studio {#mindsdb}
+
+[MindsDB](https://mindsdb.com/) is an open-source AI layer for databases including ClickHouse that allows you to effortlessly develop, train and deploy state-of-the-art machine learning models. MindsDB Studio(GUI) allows you to train new models from database, interpret predictions made by the model, identify potential data biases, and evaluate and visualize model accuracy using the Explainable AI function to adapt and tune your Machine Learning models faster.
+
+### DBM {#dbm}
+
+[DBM](https://dbm.incubator.edurt.io/) DBM is a visual management tool for ClickHouse!
+
+Features:
+
+-   Support query history (pagination, clear all, etc.)
+-   Support selected sql clauses query
+-   Support terminating query
+-   Support table management (metadata, delete, preview)
+-   Support database management (delete, create)
+-   Support custom query
+-   Support multiple data sources management(connection test, monitoring)
+-   Support monitor (processor, connection, query)
+-   Support migrate data
+
+### Bytebase {#bytebase}
+
+[Bytebase](https://bytebase.com) is a web-based, open source schema change and version control tool for teams. It supports various databases including ClickHouse.
+
+Features:
+
+-   Schema review between developers and DBAs.
+-   Database-as-Code, version control the schema in VCS such GitLab and trigger the deployment upon code commit.
+-   Streamlined deployment with per-environment policy.
+-   Full migration history.
+-   Schema drift detection.
+-   Backup and restore.
+-   RBAC.
+
+### Zeppelin-Interpreter-for-ClickHouse {#zeppelin-interpreter-for-clickhouse}
+
+[Zeppelin-Interpreter-for-ClickHouse](https://github.com/SiderZhang/Zeppelin-Interpreter-for-ClickHouse) is a [Zeppelin](https://zeppelin.apache.org) interpreter for ClickHouse. Compared with JDBC interpreter, it can provide better timeout control for long running queries.
+
+## Commercial {#commercial}
+
+### DataGrip {#datagrip}
+
+[DataGrip](https://www.jetbrains.com/datagrip/) is a database IDE from JetBrains with dedicated support for ClickHouse. It is also embedded in other IntelliJ-based tools: PyCharm, IntelliJ IDEA, GoLand, PhpStorm and others.
+
+Features:
+
+-   Very fast code completion.
+-   ClickHouse syntax highlighting.
+-   Support for features specific to ClickHouse, for example, nested columns, table engines.
+-   Data Editor.
+-   Refactorings.
+-   Search and Navigation.
+
+### Yandex DataLens {#yandex-datalens}
+
+[Yandex DataLens](https://cloud.yandex.ru/services/datalens) is a service of data visualization and analytics.
+
+Features:
+
+-   Wide range of available visualizations, from simple bar charts to complex dashboards.
+-   Dashboards could be made publicly available.
+-   Support for multiple data sources including ClickHouse.
+-   Storage for materialized data based on ClickHouse.
+
+DataLens is [available for free](https://cloud.yandex.com/docs/datalens/pricing) for low-load projects, even for commercial use.
+
+-   [DataLens documentation](https://cloud.yandex.com/docs/datalens/).
+-   [Tutorial](https://cloud.yandex.com/docs/solutions/datalens/data-from-ch-visualization) on visualizing data from a ClickHouse database.
+
+### Holistics Software {#holistics-software}
+
+[Holistics](https://www.holistics.io/) is a full-stack data platform and business intelligence tool.
+
+Features:
+
+-   Automated email, Slack and Google Sheet schedules of reports.
+-   SQL editor with visualizations, version control, auto-completion, reusable query components and dynamic filters.
+-   Embedded analytics of reports and dashboards via iframe.
+-   Data preparation and ETL capabilities.
+-   SQL data modelling support for relational mapping of data.
+
+### Looker {#looker}
+
+[Looker](https://looker.com) is a data platform and business intelligence tool with support for 50+ database dialects including ClickHouse. Looker is available as a SaaS platform and self-hosted. Users can use Looker via the browser to explore data, build visualizations and dashboards, schedule reports, and share their insights with colleagues. Looker provides a rich set of tools to embed these features in other applications, and an API
+to integrate data with other applications.
+
+Features:
+
+-   Easy and agile development using LookML, a language which supports curated
+    [Data Modeling](https://looker.com/platform/data-modeling) to support report writers and end-users.
+-   Powerful workflow integration via Looker’s [Data Actions](https://looker.com/platform/actions).
+
+[How to configure ClickHouse in Looker.](https://docs.looker.com/setup-and-management/database-config/clickhouse)
+
+### SeekTable {#seektable}
+
+[SeekTable](https://www.seektable.com) is a self-service BI tool for data exploration and operational reporting. It is available both as a cloud service and a self-hosted version. Reports from SeekTable may be embedded into any web-app.
+
+Features:
+
+-   Business users-friendly reports builder.
+-   Powerful report parameters for SQL filtering and report-specific query customizations.
+-   Can connect to ClickHouse both with a native TCP/IP endpoint and a HTTP(S) interface (2 different drivers).
+-   It is possible to use all power of ClickHouse SQL dialect in dimensions/measures definitions.
+-   [Web API](https://www.seektable.com/help/web-api-integration) for automated reports generation.
+-   Supports reports development flow with account data [backup/restore](https://www.seektable.com/help/self-hosted-backup-restore); data models (cubes) / reports configuration is a human-readable XML and can be stored under version control system.
+
+SeekTable is [free](https://www.seektable.com/help/cloud-pricing) for personal/individual usage.
+
+[How to configure ClickHouse connection in SeekTable.](https://www.seektable.com/help/clickhouse-pivot-table)
+
+### Chadmin {#chadmin}
+
+[Chadmin](https://github.com/bun4uk/chadmin) is a simple UI where you can visualize your currently running queries on your ClickHouse cluster and info about them and kill them if you want.
+
+### TABLUM.IO {#tablum_io}
+
+[TABLUM.IO](https://tablum.io/) — an online query and analytics tool for ETL and visualization. It allows connecting to ClickHouse, query data via a versatile SQL console as well as to load data from static files and 3rd party services. TABLUM.IO can visualize data results as charts and tables.
+
+Features:
+- ETL: data loading from popular databases, local and remote files, API invocations.
+- Versatile SQL console with syntax highlight and visual query builder.
+- Data visualization as charts and tables.
+- Data materialization and sub-queries.
+- Data reporting to Slack, Telegram or email.
+- Data pipelining via proprietary API.
+- Data export in JSON, CSV, SQL, HTML formats.
+- Web-based interface.
+
+TABLUM.IO can be run as a self-hosted solution (as a docker image) or in the cloud.
+License: [commercial](https://tablum.io/pricing) product with 3-month free period. 
+
+Try it out for free [in the cloud](https://tablum.io/try).
+Learn more about the product at [TABLUM.IO](https://tablum.io/)
+
+[Original article](https://clickhouse.com/docs/en/interfaces/third-party/gui/) <!--hide-->
diff --git a/docs/en/reference/interfaces/third-party/index.md b/docs/en/reference/interfaces/third-party/index.md
new file mode 100644
index 00000000000..c9be2b6ada9
--- /dev/null
+++ b/docs/en/reference/interfaces/third-party/index.md
@@ -0,0 +1,17 @@
+---
+toc_folder_title: Third-Party
+sidebar_position: 24
+---
+
+# Third-Party Interfaces {#third-party-interfaces}
+
+This is a collection of links to third-party tools that provide some sort of interface to ClickHouse. It can be either visual interface, command-line interface or an API:
+
+-   [Client libraries](../../interfaces/third-party/client-libraries.md)
+-   [Integrations](../../interfaces/third-party/integrations.md)
+-   [GUI](../../interfaces/third-party/gui.md)
+-   [Proxies](../../interfaces/third-party/proxy.md)
+
+:::note
+Generic tools that support common API like [ODBC](../../interfaces/odbc.md) or [JDBC](../../interfaces/jdbc.md) usually can work with ClickHouse as well, but are not listed here because there are way too many of them.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/interfaces/third-party/integrations.md b/docs/en/reference/interfaces/third-party/integrations.md
new file mode 100644
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+---
+sidebar_position: 27
+sidebar_label: Integrations
+---
+
+# Integration Libraries from Third-party Developers {#integration-libraries-from-third-party-developers}
+
+:::warning Disclaimer
+ClickHouse, Inc. does **not** maintain the tools and libraries listed below and haven’t done extensive testing to ensure their quality.
+:::
+
+## Infrastructure Products {#infrastructure-products}
+
+-   Relational database management systems
+    -   [MySQL](https://www.mysql.com)
+        -   [mysql2ch](https://github.com/long2ice/mysql2ch)
+        -   [ProxySQL](https://github.com/sysown/proxysql/wiki/ClickHouse-Support)
+        -   [clickhouse-mysql-data-reader](https://github.com/Altinity/clickhouse-mysql-data-reader)
+        -   [horgh-replicator](https://github.com/larsnovikov/horgh-replicator)
+    -   [PostgreSQL](https://www.postgresql.org)
+        -   [clickhousedb_fdw](https://github.com/Percona-Lab/clickhousedb_fdw)
+        -   [infi.clickhouse_fdw](https://github.com/Infinidat/infi.clickhouse_fdw) (uses [infi.clickhouse_orm](https://github.com/Infinidat/infi.clickhouse_orm))
+        -   [pg2ch](https://github.com/mkabilov/pg2ch)
+        -   [clickhouse_fdw](https://github.com/adjust/clickhouse_fdw)
+    -   [MSSQL](https://en.wikipedia.org/wiki/Microsoft_SQL_Server)
+        -   [ClickHouseMigrator](https://github.com/zlzforever/ClickHouseMigrator)
+-   Message queues
+    -   [Kafka](https://kafka.apache.org)
+        -   [clickhouse_sinker](https://github.com/housepower/clickhouse_sinker) (uses [Go client](https://github.com/ClickHouse/clickhouse-go/))
+        -   [stream-loader-clickhouse](https://github.com/adform/stream-loader)
+-   Stream processing
+    -   [Flink](https://flink.apache.org)
+        -   [flink-clickhouse-sink](https://github.com/ivi-ru/flink-clickhouse-sink)
+-   Object storages
+    -   [S3](https://en.wikipedia.org/wiki/Amazon_S3)
+        -   [clickhouse-backup](https://github.com/AlexAkulov/clickhouse-backup)
+-   Container orchestration
+    -   [Kubernetes](https://kubernetes.io)
+        -   [clickhouse-operator](https://github.com/Altinity/clickhouse-operator)
+-   Configuration management
+    -   [puppet](https://puppet.com)
+        -   [innogames/clickhouse](https://forge.puppet.com/innogames/clickhouse)
+        -   [mfedotov/clickhouse](https://forge.puppet.com/mfedotov/clickhouse)
+-   Monitoring
+    -   [Graphite](https://graphiteapp.org)
+        -   [graphouse](https://github.com/ClickHouse/graphouse)
+        -   [carbon-clickhouse](https://github.com/lomik/carbon-clickhouse)
+        -   [graphite-clickhouse](https://github.com/lomik/graphite-clickhouse)
+        -   [graphite-ch-optimizer](https://github.com/innogames/graphite-ch-optimizer) - optimizes staled partitions in [\*GraphiteMergeTree](../../engines/table-engines/mergetree-family/graphitemergetree.md#graphitemergetree) if rules from [rollup configuration](../../engines/table-engines/mergetree-family/graphitemergetree.md#rollup-configuration) could be applied
+    -   [Grafana](https://grafana.com/)
+        -   [clickhouse-grafana](https://github.com/Vertamedia/clickhouse-grafana)
+    -   [Prometheus](https://prometheus.io/)
+        -   [clickhouse_exporter](https://github.com/f1yegor/clickhouse_exporter)
+        -   [PromHouse](https://github.com/Percona-Lab/PromHouse)
+        -   [clickhouse_exporter](https://github.com/hot-wifi/clickhouse_exporter) (uses [Go client](https://github.com/kshvakov/clickhouse/))
+    -   [Nagios](https://www.nagios.org/)
+        -   [check_clickhouse](https://github.com/exogroup/check_clickhouse/)
+        -   [check_clickhouse.py](https://github.com/innogames/igmonplugins/blob/master/src/check_clickhouse.py)
+    -   [Zabbix](https://www.zabbix.com)
+        -   [clickhouse-zabbix-template](https://github.com/Altinity/clickhouse-zabbix-template)
+    -   [Sematext](https://sematext.com/)
+        -   [clickhouse integration](https://github.com/sematext/sematext-agent-integrations/tree/master/clickhouse)
+-   Logging
+    -   [rsyslog](https://www.rsyslog.com/)
+        -   [omclickhouse](https://www.rsyslog.com/doc/master/configuration/modules/omclickhouse.html)
+    -   [fluentd](https://www.fluentd.org)
+        -   [loghouse](https://github.com/flant/loghouse) (for [Kubernetes](https://kubernetes.io))
+    -   [logagent](https://www.sematext.com/logagent)
+        -   [logagent output-plugin-clickhouse](https://sematext.com/docs/logagent/output-plugin-clickhouse/)
+-   Geo
+    -   [MaxMind](https://dev.maxmind.com/geoip/)
+        -   [clickhouse-maxmind-geoip](https://github.com/AlexeyKupershtokh/clickhouse-maxmind-geoip)
+-   AutoML
+    -   [MindsDB](https://mindsdb.com/)
+        -   [MindsDB](https://github.com/mindsdb/mindsdb) - Predictive AI layer for ClickHouse database.
+
+## Programming Language Ecosystems {#programming-language-ecosystems}
+
+-   Python
+    -   [SQLAlchemy](https://www.sqlalchemy.org)
+        -   [sqlalchemy-clickhouse](https://github.com/cloudflare/sqlalchemy-clickhouse) (uses [infi.clickhouse_orm](https://github.com/Infinidat/infi.clickhouse_orm))
+    -   [pandas](https://pandas.pydata.org)
+        -   [pandahouse](https://github.com/kszucs/pandahouse)
+-   PHP
+    -   [Doctrine](https://www.doctrine-project.org/)
+        -   [dbal-clickhouse](https://packagist.org/packages/friendsofdoctrine/dbal-clickhouse)
+-   R
+    -   [dplyr](https://db.rstudio.com/dplyr/)
+        -   [RClickHouse](https://github.com/IMSMWU/RClickHouse) (uses [clickhouse-cpp](https://github.com/artpaul/clickhouse-cpp))
+-   Java
+    -   [Hadoop](http://hadoop.apache.org)
+        -   [clickhouse-hdfs-loader](https://github.com/jaykelin/clickhouse-hdfs-loader) (uses [JDBC](../../sql-reference/table-functions/jdbc.md))
+-   Scala
+    -   [Akka](https://akka.io)
+        -   [clickhouse-scala-client](https://github.com/crobox/clickhouse-scala-client)
+-   C#
+    -   [ADO.NET](https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/ado-net-overview)
+        -   [ClickHouse.Ado](https://github.com/killwort/ClickHouse-Net)
+        -   [ClickHouse.Client](https://github.com/DarkWanderer/ClickHouse.Client)
+        -   [ClickHouse.Net](https://github.com/ilyabreev/ClickHouse.Net)
+        -   [ClickHouse.Net.Migrations](https://github.com/ilyabreev/ClickHouse.Net.Migrations)
+-   Elixir
+    -   [Ecto](https://github.com/elixir-ecto/ecto)
+        -   [clickhouse_ecto](https://github.com/appodeal/clickhouse_ecto)
+-   Ruby
+    -   [Ruby on Rails](https://rubyonrails.org/)
+        -   [activecube](https://github.com/bitquery/activecube)
+        -   [ActiveRecord](https://github.com/PNixx/clickhouse-activerecord)
+    -   [GraphQL](https://github.com/graphql)
+        -   [activecube-graphql](https://github.com/bitquery/activecube-graphql)
+
+[Original article](https://clickhouse.com/docs/en/interfaces/third-party/integrations/) <!--hide-->
diff --git a/docs/en/reference/interfaces/third-party/proxy.md b/docs/en/reference/interfaces/third-party/proxy.md
new file mode 100644
index 00000000000..45077cb6a89
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@@ -0,0 +1,44 @@
+---
+sidebar_position: 29
+sidebar_label: Proxies
+---
+
+# Proxy Servers from Third-party Developers {#proxy-servers-from-third-party-developers}
+
+## chproxy {#chproxy}
+
+[chproxy](https://github.com/Vertamedia/chproxy), is an HTTP proxy and load balancer for ClickHouse database.
+
+Features:
+
+-   Per-user routing and response caching.
+-   Flexible limits.
+-   Automatic SSL certificate renewal.
+
+Implemented in Go.
+
+## KittenHouse {#kittenhouse}
+
+[KittenHouse](https://github.com/VKCOM/kittenhouse) is designed to be a local proxy between ClickHouse and application server in case it’s impossible or inconvenient to buffer INSERT data on your application side.
+
+Features:
+
+-   In-memory and on-disk data buffering.
+-   Per-table routing.
+-   Load-balancing and health checking.
+
+Implemented in Go.
+
+## ClickHouse-Bulk {#clickhouse-bulk}
+
+[ClickHouse-Bulk](https://github.com/nikepan/clickhouse-bulk) is a simple ClickHouse insert collector.
+
+Features:
+
+-   Group requests and send by threshold or interval.
+-   Multiple remote servers.
+-   Basic authentication.
+
+Implemented in Go.
+
+[Original article](https://clickhouse.com/docs/en/interfaces/third-party/proxy/) <!--hide-->
diff --git a/docs/en/reference/operations/_category_.yml b/docs/en/reference/operations/_category_.yml
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index 00000000000..3dcbd254a3f
--- /dev/null
+++ b/docs/en/reference/operations/_category_.yml
@@ -0,0 +1,4 @@
+position: 70 
+label: 'Operations'
+collapsible: true
+collapsed: true
\ No newline at end of file
diff --git a/docs/en/reference/operations/access-rights.md b/docs/en/reference/operations/access-rights.md
new file mode 100644
index 00000000000..7d75c47df2b
--- /dev/null
+++ b/docs/en/reference/operations/access-rights.md
@@ -0,0 +1,154 @@
+---
+sidebar_position: 48
+sidebar_label: Access Control and Account Management
+---
+
+# Access Control and Account Management {#access-control}
+
+ClickHouse supports access control management based on [RBAC](https://en.wikipedia.org/wiki/Role-based_access_control) approach.
+
+ClickHouse access entities:
+- [User account](#user-account-management)
+- [Role](#role-management)
+- [Row Policy](#row-policy-management)
+- [Settings Profile](#settings-profiles-management)
+- [Quota](#quotas-management)
+
+You can configure access entities using:
+
+-   SQL-driven workflow.
+
+    You need to [enable](#enabling-access-control) this functionality.
+
+-   Server [configuration files](../operations/configuration-files.md) `users.xml` and `config.xml`.
+
+We recommend using SQL-driven workflow. Both of the configuration methods work simultaneously, so if you use the server configuration files for managing accounts and access rights, you can smoothly switch to SQL-driven workflow.
+
+:::warning    
+You can’t manage the same access entity by both configuration methods simultaneously.
+:::
+
+To see all users, roles, profiles, etc. and all their grants use [SHOW ACCESS](../sql-reference/statements/show.md#show-access-statement) statement.
+
+## Usage {#access-control-usage}
+
+By default, the ClickHouse server provides the `default` user account which is not allowed using SQL-driven access control and account management but has all the rights and permissions. The `default` user account is used in any cases when the username is not defined, for example, at login from client or in distributed queries. In distributed query processing a default user account is used, if the configuration of the server or cluster does not specify the [user and password](../engines/table-engines/special/distributed.md) properties.
+
+If you just started using ClickHouse, consider the following scenario:
+
+1.  [Enable](#enabling-access-control) SQL-driven access control and account management for the `default` user.
+2.  Log in to the `default` user account and create all the required users. Don’t forget to create an administrator account (`GRANT ALL ON *.* TO admin_user_account WITH GRANT OPTION`).
+3.  [Restrict permissions](../operations/settings/permissions-for-queries.md#permissions_for_queries) for the `default` user and disable SQL-driven access control and account management for it.
+
+### Properties of Current Solution {#access-control-properties}
+
+-   You can grant permissions for databases and tables even if they do not exist.
+-   If a table was deleted, all the privileges that correspond to this table are not revoked. This means that even if you create a new table with the same name later, all the privileges remain valid. To revoke privileges corresponding to the deleted table, you need to execute, for example, the `REVOKE ALL PRIVILEGES ON db.table FROM ALL` query.
+-   There are no lifetime settings for privileges.
+
+## User Account {#user-account-management}
+
+A user account is an access entity that allows to authorize someone in ClickHouse. A user account contains:
+
+-   Identification information.
+-   [Privileges](../sql-reference/statements/grant.md#grant-privileges) that define a scope of queries the user can execute.
+-   Hosts allowed to connect to the ClickHouse server.
+-   Assigned and default roles.
+-   Settings with their constraints applied by default at user login.
+-   Assigned settings profiles.
+
+Privileges can be granted to a user account by the [GRANT](../sql-reference/statements/grant.md) query or by assigning [roles](#role-management). To revoke privileges from a user, ClickHouse provides the [REVOKE](../sql-reference/statements/revoke.md) query. To list privileges for a user, use the [SHOW GRANTS](../sql-reference/statements/show.md#show-grants-statement) statement.
+
+Management queries:
+
+-   [CREATE USER](../sql-reference/statements/create/user.md)
+-   [ALTER USER](../sql-reference/statements/alter/user.md#alter-user-statement)
+-   [DROP USER](../sql-reference/statements/drop.md)
+-   [SHOW CREATE USER](../sql-reference/statements/show.md#show-create-user-statement)
+-   [SHOW USERS](../sql-reference/statements/show.md#show-users-statement)
+
+### Settings Applying {#access-control-settings-applying}
+
+Settings can be configured differently: for a user account, in its granted roles and in settings profiles. At user login, if a setting is configured for different access entities, the value and constraints of this setting are applied as follows (from higher to lower priority):
+
+1.  User account settings.
+2.  The settings of default roles of the user account. If a setting is configured in some roles, then order of the setting application is undefined.
+3.  The settings from settings profiles assigned to a user or to its default roles. If a setting is configured in some profiles, then order of setting application is undefined.
+4.  Settings applied to all the server by default or from the [default profile](../operations/server-configuration-parameters/settings.md#default-profile).
+
+## Role {#role-management}
+
+Role is a container for access entities that can be granted to a user account.
+
+Role contains:
+
+-   [Privileges](../sql-reference/statements/grant.md#grant-privileges)
+-   Settings and constraints
+-   List of assigned roles
+
+Management queries:
+
+-   [CREATE ROLE](../sql-reference/statements/create/role.md)
+-   [ALTER ROLE](../sql-reference/statements/alter/role.md#alter-role-statement)
+-   [DROP ROLE](../sql-reference/statements/drop.md)
+-   [SET ROLE](../sql-reference/statements/set-role.md)
+-   [SET DEFAULT ROLE](../sql-reference/statements/set-role.md#set-default-role-statement)
+-   [SHOW CREATE ROLE](../sql-reference/statements/show.md#show-create-role-statement)
+-   [SHOW ROLES](../sql-reference/statements/show.md#show-roles-statement)
+
+Privileges can be granted to a role by the [GRANT](../sql-reference/statements/grant.md) query. To revoke privileges from a role ClickHouse provides the [REVOKE](../sql-reference/statements/revoke.md) query.
+
+## Row Policy {#row-policy-management}
+
+Row policy is a filter that defines which of the rows are available to a user or a role. Row policy contains filters for one particular table, as well as a list of roles and/or users which should use this row policy.
+
+:::warning    
+Row policies makes sense only for users with readonly access. If user can modify table or copy partitions between tables, it defeats the restrictions of row policies.
+:::
+
+Management queries:
+
+-   [CREATE ROW POLICY](../sql-reference/statements/create/row-policy.md)
+-   [ALTER ROW POLICY](../sql-reference/statements/alter/row-policy.md#alter-row-policy-statement)
+-   [DROP ROW POLICY](../sql-reference/statements/drop.md#drop-row-policy-statement)
+-   [SHOW CREATE ROW POLICY](../sql-reference/statements/show.md#show-create-row-policy-statement)
+-   [SHOW POLICIES](../sql-reference/statements/show.md#show-policies-statement)
+
+## Settings Profile {#settings-profiles-management}
+
+Settings profile is a collection of [settings](../operations/settings/index.md). Settings profile contains settings and constraints, as well as a list of roles and/or users to which this profile is applied.
+
+Management queries:
+
+-   [CREATE SETTINGS PROFILE](../sql-reference/statements/create/settings-profile.md#create-settings-profile-statement)
+-   [ALTER SETTINGS PROFILE](../sql-reference/statements/alter/settings-profile.md#alter-settings-profile-statement)
+-   [DROP SETTINGS PROFILE](../sql-reference/statements/drop.md#drop-settings-profile-statement)
+-   [SHOW CREATE SETTINGS PROFILE](../sql-reference/statements/show.md#show-create-settings-profile-statement)
+-   [SHOW PROFILES](../sql-reference/statements/show.md#show-profiles-statement)
+
+## Quota {#quotas-management}
+
+Quota limits resource usage. See [Quotas](../operations/quotas.md).
+
+Quota contains a set of limits for some durations, as well as a list of roles and/or users which should use this quota.
+
+Management queries:
+
+-   [CREATE QUOTA](../sql-reference/statements/create/quota.md)
+-   [ALTER QUOTA](../sql-reference/statements/alter/quota.md#alter-quota-statement)
+-   [DROP QUOTA](../sql-reference/statements/drop.md#drop-quota-statement)
+-   [SHOW CREATE QUOTA](../sql-reference/statements/show.md#show-create-quota-statement)
+-   [SHOW QUOTA](../sql-reference/statements/show.md#show-quota-statement)
+-   [SHOW QUOTAS](../sql-reference/statements/show.md#show-quotas-statement)
+
+## Enabling SQL-driven Access Control and Account Management {#enabling-access-control}
+
+-   Setup a directory for configurations storage.
+
+    ClickHouse stores access entity configurations in the folder set in the [access_control_path](../operations/server-configuration-parameters/settings.md#access_control_path) server configuration parameter.
+
+-   Enable SQL-driven access control and account management for at least one user account.
+
+    By default, SQL-driven access control and account management is disabled for all users. You need to configure at least one user in the `users.xml` configuration file and set the value of the [access_management](../operations/settings/settings-users.md#access_management-user-setting) setting to 1.
+
+[Original article](https://clickhouse.com/docs/en/operations/access_rights/) <!--hide-->
diff --git a/docs/en/reference/operations/backup.md b/docs/en/reference/operations/backup.md
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+---
+sidebar_position: 49
+sidebar_label: Data Backup
+---
+
+# Data Backup {#data-backup}
+
+While [replication](../engines/table-engines/mergetree-family/replication.md) provides protection from hardware failures, it does not protect against human errors: accidental deletion of data, deletion of the wrong table or a table on the wrong cluster, and software bugs that result in incorrect data processing or data corruption. In many cases mistakes like these will affect all replicas. ClickHouse has built-in safeguards to prevent some types of mistakes — for example, by default [you can’t just drop tables with a MergeTree-like engine containing more than 50 Gb of data](server-configuration-parameters/settings.md#max-table-size-to-drop). However, these safeguards do not cover all possible cases and can be circumvented.
+
+In order to effectively mitigate possible human errors, you should carefully prepare a strategy for backing up and restoring your data **in advance**.
+
+Each company has different resources available and business requirements, so there’s no universal solution for ClickHouse backups and restores that will fit every situation. What works for one gigabyte of data likely won’t work for tens of petabytes. There are a variety of possible approaches with their own pros and cons, which will be discussed below. It is a good idea to use several approaches instead of just one in order to compensate for their various shortcomings.
+
+:::note    
+Keep in mind that if you backed something up and never tried to restore it, chances are that restore will not work properly when you actually need it (or at least it will take longer than business can tolerate). So whatever backup approach you choose, make sure to automate the restore process as well, and practice it on a spare ClickHouse cluster regularly.
+:::
+
+## Duplicating Source Data Somewhere Else {#duplicating-source-data-somewhere-else}
+
+Often data that is ingested into ClickHouse is delivered through some sort of persistent queue, such as [Apache Kafka](https://kafka.apache.org). In this case it is possible to configure an additional set of subscribers that will read the same data stream while it is being written to ClickHouse and store it in cold storage somewhere. Most companies already have some default recommended cold storage, which could be an object store or a distributed filesystem like [HDFS](https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-hdfs/HdfsDesign.html).
+
+## Filesystem Snapshots {#filesystem-snapshots}
+
+Some local filesystems provide snapshot functionality (for example, [ZFS](https://en.wikipedia.org/wiki/ZFS)), but they might not be the best choice for serving live queries. A possible solution is to create additional replicas with this kind of filesystem and exclude them from the [Distributed](../engines/table-engines/special/distributed.md) tables that are used for `SELECT` queries. Snapshots on such replicas will be out of reach of any queries that modify data. As a bonus, these replicas might have special hardware configurations with more disks attached per server, which would be cost-effective.
+
+## clickhouse-copier {#clickhouse-copier}
+
+[clickhouse-copier](../operations/utilities/clickhouse-copier.md) is a versatile tool that was initially created to re-shard petabyte-sized tables. It can also be used for backup and restore purposes because it reliably copies data between ClickHouse tables and clusters.
+
+For smaller volumes of data, a simple `INSERT INTO ... SELECT ...` to remote tables might work as well.
+
+## Manipulations with Parts {#manipulations-with-parts}
+
+ClickHouse allows using the `ALTER TABLE ... FREEZE PARTITION ...` query to create a local copy of table partitions. This is implemented using hardlinks to the `/var/lib/clickhouse/shadow/` folder, so it usually does not consume extra disk space for old data. The created copies of files are not handled by ClickHouse server, so you can just leave them there: you will have a simple backup that does not require any additional external system, but it will still be prone to hardware issues. For this reason, it’s better to remotely copy them to another location and then remove the local copies. Distributed filesystems and object stores are still a good options for this, but normal attached file servers with a large enough capacity might work as well (in this case the transfer will occur via the network filesystem or maybe [rsync](https://en.wikipedia.org/wiki/Rsync)).
+Data can be restored from backup using the `ALTER TABLE ... ATTACH PARTITION ...`
+
+For more information about queries related to partition manipulations, see the [ALTER documentation](../sql-reference/statements/alter/partition.md#alter_manipulations-with-partitions).
+
+A third-party tool is available to automate this approach: [clickhouse-backup](https://github.com/AlexAkulov/clickhouse-backup).
+
+[Original article](https://clickhouse.com/docs/en/operations/backup/) <!--hide-->
diff --git a/docs/en/reference/operations/caches.md b/docs/en/reference/operations/caches.md
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+---
+sidebar_position: 65
+sidebar_label: Caches
+---
+
+# Cache Types {#cache-types}
+
+When performing queries, ClichHouse uses different caches.
+
+Main cache types:
+
+- `mark_cache` — Cache of marks used by table engines of the [MergeTree](../engines/table-engines/mergetree-family/mergetree.md) family.
+- `uncompressed_cache` — Cache of uncompressed data used by table engines of the [MergeTree](../engines/table-engines/mergetree-family/mergetree.md) family.
+
+Additional cache types:
+
+- DNS cache.
+- [Regexp](../interfaces/formats.md#data-format-regexp) cache.
+- Compiled expressions cache.
+- [Avro format](../interfaces/formats.md#data-format-avro) schemas cache.
+- [Dictionaries](../sql-reference/dictionaries/index.md) data cache.
+
+Indirectly used:
+
+- OS page cache.
+
+To drop cache, use [SYSTEM DROP ... CACHE](../sql-reference/statements/system.md) statements.
+
+[Original article](https://clickhouse.com/docs/en/operations/caches/) <!--hide-->
diff --git a/docs/en/reference/operations/clickhouse-keeper.md b/docs/en/reference/operations/clickhouse-keeper.md
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+---
+sidebar_position: 66
+sidebar_label: ClickHouse Keeper
+---
+
+# [pre-production] ClickHouse Keeper {#clickHouse-keeper}
+
+ClickHouse server uses [ZooKeeper](https://zookeeper.apache.org/) coordination system for data [replication](../engines/table-engines/mergetree-family/replication.md) and [distributed DDL](../sql-reference/distributed-ddl.md) queries execution. ClickHouse Keeper is an alternative coordination system compatible with ZooKeeper.
+
+:::warning    
+This feature is currently in the pre-production stage. We test it in our CI and on small internal installations.
+:::
+
+## Implementation details {#implementation-details}
+
+ZooKeeper is one of the first well-known open-source coordination systems. It's implemented in Java, has quite a simple and powerful data model. ZooKeeper's coordination algorithm called ZAB (ZooKeeper Atomic Broadcast) doesn't provide linearizability guarantees for reads, because each ZooKeeper node serves reads locally. Unlike ZooKeeper ClickHouse Keeper is written in C++ and uses [RAFT algorithm](https://raft.github.io/) [implementation](https://github.com/eBay/NuRaft). This algorithm allows to have linearizability for reads and writes, has several open-source implementations in different languages.
+
+By default, ClickHouse Keeper provides the same guarantees as ZooKeeper (linearizable writes, non-linearizable reads). It has a compatible client-server protocol, so any standard ZooKeeper client can be used to interact with ClickHouse Keeper. Snapshots and logs have an incompatible format with ZooKeeper, but `clickhouse-keeper-converter` tool allows to convert ZooKeeper data to ClickHouse Keeper snapshot. Interserver protocol in ClickHouse Keeper is also incompatible with ZooKeeper so mixed ZooKeeper / ClickHouse Keeper cluster is impossible.
+
+ClickHouse Keeper supports Access Control List (ACL) the same way as [ZooKeeper](https://zookeeper.apache.org/doc/r3.1.2/zookeeperProgrammers.html#sc_ZooKeeperAccessControl) does. ClickHouse Keeper supports the same set of permissions and has the identical built-in schemes: `world`, `auth`, `digest`, `host` and `ip`. Digest authentication scheme uses pair `username:password`. Password is encoded in Base64. 
+
+:::note    
+External integrations are not supported.
+:::
+
+## Configuration {#configuration}
+
+ClickHouse Keeper can be used as a standalone replacement for ZooKeeper or as an internal part of the ClickHouse server, but in both cases configuration is almost the same `.xml` file. The main ClickHouse Keeper configuration tag is `<keeper_server>`. Keeper configuration has the following parameters:
+
+-    `tcp_port` — Port for a client to connect (default for ZooKeeper is `2181`).
+-    `tcp_port_secure` — Secure port for an SSL connection between client and keeper-server.
+-    `server_id` — Unique server id, each participant of the ClickHouse Keeper cluster must have a unique number (1, 2, 3, and so on).
+-    `log_storage_path` — Path to coordination logs, better to store logs on the non-busy device (same for ZooKeeper).
+-    `snapshot_storage_path` — Path to coordination snapshots.
+
+Other common parameters are inherited from the ClickHouse server config (`listen_host`, `logger`, and so on).
+
+Internal coordination settings are located in `<keeper_server>.<coordination_settings>` section:
+
+-    `operation_timeout_ms` — Timeout for a single client operation (ms) (default: 10000).
+-    `min_session_timeout_ms` — Min timeout for client session (ms) (default: 10000).
+-    `session_timeout_ms` — Max timeout for client session (ms) (default: 100000).
+-    `dead_session_check_period_ms` — How often ClickHouse Keeper check dead sessions and remove them (ms) (default: 500).
+-    `heart_beat_interval_ms` — How often a ClickHouse Keeper leader will send heartbeats to followers (ms) (default: 500).
+-    `election_timeout_lower_bound_ms` — If the follower didn't receive heartbeats from the leader in this interval, then it can initiate leader election (default: 1000).
+-    `election_timeout_upper_bound_ms` — If the follower didn't receive heartbeats from the leader in this interval, then it must initiate leader election (default: 2000).
+-    `rotate_log_storage_interval` — How many log records to store in a single file (default: 100000).
+-    `reserved_log_items` — How many coordination log records to store before compaction (default: 100000).
+-    `snapshot_distance` — How often ClickHouse Keeper will create new snapshots (in the number of records in logs) (default: 100000).
+-    `snapshots_to_keep` — How many snapshots to keep (default: 3).
+-    `stale_log_gap` — Threshold when leader considers follower as stale and sends the snapshot to it instead of logs (default: 10000).
+-    `fresh_log_gap` — When node became fresh (default: 200).
+-    `max_requests_batch_size` - Max size of batch in requests count before it will be sent to RAFT (default: 100).
+-    `force_sync` — Call `fsync` on each write to coordination log (default: true).
+-    `quorum_reads` — Execute read requests as writes through whole RAFT consensus with similar speed (default: false).
+-    `raft_logs_level` — Text logging level about coordination (trace, debug, and so on) (default: system default).
+-    `auto_forwarding` — Allow to forward write requests from followers to the leader (default: true).
+-    `shutdown_timeout` — Wait to finish internal connections and shutdown (ms) (default: 5000).
+-    `startup_timeout` — If the server doesn't connect to other quorum participants in the specified timeout it will terminate (ms) (default: 30000).
+-    `four_letter_word_white_list` — White list of 4lw commands (default: "conf,cons,crst,envi,ruok,srst,srvr,stat,wchc,wchs,dirs,mntr,isro").
+
+Quorum configuration is located in `<keeper_server>.<raft_configuration>` section and contain servers description.
+
+The only parameter for the whole quorum is `secure`, which enables encrypted connection for communication between quorum participants. The parameter can be set `true` if SSL connection is required for internal communication between nodes, or left unspecified otherwise.
+
+The main parameters for each `<server>` are:
+
+-    `id` — Server identifier in a quorum.
+-    `hostname` — Hostname where this server is placed.
+-    `port` — Port where this server listens for connections.
+
+
+Examples of configuration for quorum with three nodes can be found in [integration tests](https://github.com/ClickHouse/ClickHouse/tree/master/tests/integration) with `test_keeper_` prefix. Example configuration for server #1:
+
+```xml
+<keeper_server>
+    <tcp_port>2181</tcp_port>
+    <server_id>1</server_id>
+    <log_storage_path>/var/lib/clickhouse/coordination/log</log_storage_path>
+    <snapshot_storage_path>/var/lib/clickhouse/coordination/snapshots</snapshot_storage_path>
+
+    <coordination_settings>
+        <operation_timeout_ms>10000</operation_timeout_ms>
+        <session_timeout_ms>30000</session_timeout_ms>
+        <raft_logs_level>trace</raft_logs_level>
+    </coordination_settings>
+
+    <raft_configuration>
+        <server>
+            <id>1</id>
+            <hostname>zoo1</hostname>
+            <port>9444</port>
+        </server>
+        <server>
+            <id>2</id>
+            <hostname>zoo2</hostname>
+            <port>9444</port>
+        </server>
+        <server>
+            <id>3</id>
+            <hostname>zoo3</hostname>
+            <port>9444</port>
+        </server>
+    </raft_configuration>
+</keeper_server>
+```
+
+## How to run {#how-to-run}
+
+ClickHouse Keeper is bundled into the ClickHouse server package, just add configuration of `<keeper_server>` and start ClickHouse server as always. If you want to run standalone ClickHouse Keeper you can start it in a similar way with:
+
+```bash
+clickhouse-keeper --config /etc/your_path_to_config/config.xml
+```
+
+If you don't have the symlink (`clickhouse-keeper`) you can create it or specify `keeper` as argument:
+
+```bash
+clickhouse keeper --config /etc/your_path_to_config/config.xml
+```
+
+## Four Letter Word Commands {#four-letter-word-commands}
+
+ClickHouse Keeper also provides 4lw commands which are almost the same with Zookeeper. Each command is composed of four letters such as `mntr`, `stat` etc. There are some more interesting commands: `stat` gives some general information about the server and connected clients, while `srvr` and `cons` give extended details on server and connections respectively.  
+
+The 4lw commands has a white list configuration `four_letter_word_white_list` which has default value "conf,cons,crst,envi,ruok,srst,srvr,stat,wchc,wchs,dirs,mntr,isro".
+
+You can issue the commands to ClickHouse Keeper via telnet or nc, at the client port.
+
+```
+echo mntr | nc localhost 9181
+```
+
+Bellow is the detailed 4lw commands:
+
+- `ruok`: Tests if server is running in a non-error state. The server will respond with imok if it is running. Otherwise it will not respond at all. A response of "imok" does not necessarily indicate that the server has joined the quorum, just that the server process is active and bound to the specified client port. Use "stat" for details on state wrt quorum and client connection information.
+
+```
+imok
+```
+
+- `mntr`: Outputs a list of variables that could be used for monitoring the health of the cluster.
+
+```
+zk_version      v21.11.1.1-prestable-7a4a0b0edef0ad6e0aa662cd3b90c3f4acf796e7
+zk_avg_latency  0
+zk_max_latency  0
+zk_min_latency  0
+zk_packets_received     68
+zk_packets_sent 68
+zk_num_alive_connections        1
+zk_outstanding_requests 0
+zk_server_state leader
+zk_znode_count  4
+zk_watch_count  1
+zk_ephemerals_count     0
+zk_approximate_data_size        723
+zk_open_file_descriptor_count   310
+zk_max_file_descriptor_count    10240
+zk_followers    0
+zk_synced_followers     0
+```
+
+- `srvr`: Lists full details for the server.
+
+```
+ClickHouse Keeper version: v21.11.1.1-prestable-7a4a0b0edef0ad6e0aa662cd3b90c3f4acf796e7
+Latency min/avg/max: 0/0/0
+Received: 2
+Sent : 2
+Connections: 1
+Outstanding: 0
+Zxid: 34
+Mode: leader
+Node count: 4
+```
+
+- `stat`: Lists brief details for the server and connected clients.
+
+```
+ClickHouse Keeper version: v21.11.1.1-prestable-7a4a0b0edef0ad6e0aa662cd3b90c3f4acf796e7
+Clients:
+ 192.168.1.1:52852(recved=0,sent=0)
+ 192.168.1.1:52042(recved=24,sent=48)
+Latency min/avg/max: 0/0/0
+Received: 4
+Sent : 4
+Connections: 1
+Outstanding: 0
+Zxid: 36
+Mode: leader
+Node count: 4
+```
+
+- `srst`: Reset server statistics. The command will affect the result of `srvr`, `mntr` and `stat`.
+
+```
+Server stats reset.
+```
+
+- `conf`: Print details about serving configuration.
+
+```
+server_id=1
+tcp_port=2181
+four_letter_word_white_list=*
+log_storage_path=./coordination/logs
+snapshot_storage_path=./coordination/snapshots
+max_requests_batch_size=100
+session_timeout_ms=30000
+operation_timeout_ms=10000
+dead_session_check_period_ms=500
+heart_beat_interval_ms=500
+election_timeout_lower_bound_ms=1000
+election_timeout_upper_bound_ms=2000
+reserved_log_items=1000000000000000
+snapshot_distance=10000
+auto_forwarding=true
+shutdown_timeout=5000
+startup_timeout=240000
+raft_logs_level=information
+snapshots_to_keep=3
+rotate_log_storage_interval=100000
+stale_log_gap=10000
+fresh_log_gap=200
+max_requests_batch_size=100
+quorum_reads=false
+force_sync=false
+compress_logs=true
+compress_snapshots_with_zstd_format=true
+configuration_change_tries_count=20
+```
+
+- `cons`: List full connection/session details for all clients connected to this server. Includes information on numbers of packets received/sent, session id, operation latencies, last operation performed, etc...
+
+```
+ 192.168.1.1:52163(recved=0,sent=0,sid=0xffffffffffffffff,lop=NA,est=1636454787393,to=30000,lzxid=0xffffffffffffffff,lresp=0,llat=0,minlat=0,avglat=0,maxlat=0)
+ 192.168.1.1:52042(recved=9,sent=18,sid=0x0000000000000001,lop=List,est=1636454739887,to=30000,lcxid=0x0000000000000005,lzxid=0x0000000000000005,lresp=1636454739892,llat=0,minlat=0,avglat=0,maxlat=0)
+```
+
+- `crst`: Reset connection/session statistics for all connections.
+
+```
+Connection stats reset.
+```
+
+- `envi`: Print details about serving environment
+
+```
+Environment:
+clickhouse.keeper.version=v21.11.1.1-prestable-7a4a0b0edef0ad6e0aa662cd3b90c3f4acf796e7
+host.name=ZBMAC-C02D4054M.local
+os.name=Darwin
+os.arch=x86_64
+os.version=19.6.0
+cpu.count=12
+user.name=root
+user.home=/Users/JackyWoo/
+user.dir=/Users/JackyWoo/project/jd/clickhouse/cmake-build-debug/programs/
+user.tmp=/var/folders/b4/smbq5mfj7578f2jzwn602tt40000gn/T/
+```
+
+
+- `dirs`: Shows the total size of snapshot and log files in bytes
+
+```
+snapshot_dir_size: 0
+log_dir_size: 3875
+```
+
+- `isro`: Tests if server is running in read-only mode. The server will respond with "ro" if in read-only mode or "rw" if not in read-only mode.
+
+```
+rw
+```
+
+- `wchs`: Lists brief information on watches for the server.
+
+```
+1 connections watching 1 paths
+Total watches:1
+```
+
+- `wchc`: Lists detailed information on watches for the server, by session. This outputs a list of sessions (connections) with associated watches (paths). Note, depending on the number of watches this operation may be expensive (ie impact server performance), use it carefully.
+
+```
+0x0000000000000001
+    /clickhouse/task_queue/ddl
+```
+
+- `wchp`: Lists detailed information on watches for the server, by path. This outputs a list of paths (znodes) with associated sessions. Note, depending on the number of watches this operation may be expensive (i. e. impact server performance), use it carefully.
+
+```
+/clickhouse/task_queue/ddl
+    0x0000000000000001
+```
+
+- `dump`: Lists the outstanding sessions and ephemeral nodes. This only works on the leader.
+
+```
+Sessions dump (2):
+0x0000000000000001
+0x0000000000000002
+Sessions with Ephemerals (1):
+0x0000000000000001
+ /clickhouse/task_queue/ddl
+```
+
+## [experimental] Migration from ZooKeeper {#migration-from-zookeeper}
+
+Seamlessly migration from ZooKeeper to ClickHouse Keeper is impossible you have to stop your ZooKeeper cluster, convert data and start ClickHouse Keeper. `clickhouse-keeper-converter` tool allows converting ZooKeeper logs and snapshots to ClickHouse Keeper snapshot. It works only with ZooKeeper > 3.4. Steps for migration:
+
+1. Stop all ZooKeeper nodes.
+
+2. Optional, but recommended: find ZooKeeper leader node, start and stop it again. It will force ZooKeeper to create a consistent snapshot.
+
+3. Run `clickhouse-keeper-converter` on a leader, for example:
+
+```bash
+clickhouse-keeper-converter --zookeeper-logs-dir /var/lib/zookeeper/version-2 --zookeeper-snapshots-dir /var/lib/zookeeper/version-2 --output-dir /path/to/clickhouse/keeper/snapshots
+```
+
+4. Copy snapshot to ClickHouse server nodes with a configured `keeper` or start ClickHouse Keeper instead of ZooKeeper. The snapshot must persist on all nodes, otherwise, empty nodes can be faster and one of them can become a leader.
+
+[Original article](https://clickhouse.com/docs/en/operations/clickhouse-keeper/) <!--hide-->
diff --git a/docs/en/reference/operations/configuration-files.md b/docs/en/reference/operations/configuration-files.md
new file mode 100644
index 00000000000..582e90544e0
--- /dev/null
+++ b/docs/en/reference/operations/configuration-files.md
@@ -0,0 +1,159 @@
+---
+sidebar_position: 50
+sidebar_label: Configuration Files
+---
+
+# Configuration Files {#configuration_files}
+
+ClickHouse supports multi-file configuration management. The main server configuration file is `/etc/clickhouse-server/config.xml` or `/etc/clickhouse-server/config.yaml`. Other files must be in the `/etc/clickhouse-server/config.d` directory. Note, that any configuration file can be written either in XML or YAML, but mixing formats in one file is not supported. For example, you can have main configs as `config.xml` and `users.xml` and write additional files in `config.d` and `users.d` directories in `.yaml`.
+
+All XML files should have the same root element, usually `<clickhouse>`. As for YAML, `clickhouse:` should not be present, the parser will insert it automatically.
+
+## Override {#override}
+
+Some settings specified in the main configuration file can be overridden in other configuration files:
+
+-   The `replace` or `remove` attributes can be specified for the elements of these configuration files.
+-   If neither is specified, it combines the contents of elements recursively, replacing values of duplicate children.
+-   If `replace` is specified, it replaces the entire element with the specified one.
+-   If `remove` is specified, it deletes the element.
+
+You can also declare attributes as coming from environment variables by using `from_env="VARIABLE_NAME"`:
+
+```xml
+<clickhouse>
+    <macros>
+        <replica from_env="REPLICA" />
+        <layer from_env="LAYER" />
+        <shard from_env="SHARD" />
+    </macros>
+</clickhouse>
+```
+
+## Substitution {#substitution}
+
+The config can also define “substitutions”. If an element has the `incl` attribute, the corresponding substitution from the file will be used as the value. By default, the path to the file with substitutions is `/etc/metrika.xml`. This can be changed in the [include_from](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-include_from) element in the server config. The substitution values are specified in `/clickhouse/substitution_name` elements in this file. If a substitution specified in `incl` does not exist, it is recorded in the log. To prevent ClickHouse from logging missing substitutions, specify the `optional="true"` attribute (for example, settings for [macros](../operations/server-configuration-parameters/settings.md#macros)).
+
+If you want to replace an entire element with a substitution use `include` as element name.
+
+XML substitution example:
+
+```xml
+<clickhouse>
+    <!-- Appends XML subtree found at `/profiles-in-zookeeper` ZK path to `<profiles>` element. -->
+    <profiles from_zk="/profiles-in-zookeeper" />
+
+    <users>
+        <!-- Replaces `include` element with the subtree found at `/users-in-zookeeper` ZK path. -->
+        <include from_zk="/users-in-zookeeper" />
+        <include from_zk="/other-users-in-zookeeper" />
+    </users>
+</clickhouse>
+```
+
+Substitutions can also be performed from ZooKeeper. To do this, specify the attribute `from_zk = "/path/to/node"`. The element value is replaced with the contents of the node at `/path/to/node` in ZooKeeper. You can also put an entire XML subtree on the ZooKeeper node and it will be fully inserted into the source element.
+
+## User Settings {#user-settings}
+
+The `config.xml` file can specify a separate config with user settings, profiles, and quotas. The relative path to this config is set in the `users_config` element. By default, it is `users.xml`. If `users_config` is omitted, the user settings, profiles, and quotas are specified directly in `config.xml`.
+
+Users configuration can be splitted into separate files similar to `config.xml` and `config.d/`.
+Directory name is defined as `users_config` setting without `.xml` postfix concatenated with `.d`.
+Directory `users.d` is used by default, as `users_config` defaults to `users.xml`.
+
+Note that configuration files are first merged taking into account [Override](#override) settings and includes are processed after that.
+
+## XML example {#example}
+
+For example, you can have separate config file for each user like this:
+
+``` bash
+$ cat /etc/clickhouse-server/users.d/alice.xml
+```
+
+``` xml
+<clickhouse>
+    <users>
+      <alice>
+          <profile>analytics</profile>
+            <networks>
+                  <ip>::/0</ip>
+            </networks>
+          <password_sha256_hex>...</password_sha256_hex>
+          <quota>analytics</quota>
+      </alice>
+    </users>
+</clickhouse>
+```
+
+## YAML examples {#example}
+
+Here you can see default config written in YAML: [config.yaml.example](https://github.com/ClickHouse/ClickHouse/blob/master/programs/server/config.yaml.example).
+
+There are some differences between YAML and XML formats in terms of ClickHouse configurations. Here are some tips for writing a configuration in YAML format.
+
+You should use a Scalar node to write a key-value pair:
+``` yaml
+key: value
+```
+
+To create a node, containing other nodes you should use a Map:
+``` yaml
+map_key:
+  key1: val1
+  key2: val2
+  key3: val3
+```
+
+To create a list of values or nodes assigned to one tag you should use a Sequence:
+``` yaml
+seq_key:
+  - val1
+  - val2
+  - key1: val3
+  - map:
+      key2: val4
+      key3: val5
+```
+
+If you want to write an attribute for a Sequence or Map node, you should use a @ prefix before the attribute key. Note, that @ is reserved by YAML standard, so you should also to wrap it into double quotes:
+
+``` yaml
+map:
+  "@attr1": value1
+  "@attr2": value2
+  key: 123
+```
+
+From that Map we will get these XML nodes:
+
+``` xml
+<map attr1="value1" attr2="value2">
+    <key>123</key>
+</map>
+```
+
+You can also set attributes for Sequence:
+
+``` yaml
+seq:
+  - "@attr1": value1
+  - "@attr2": value2
+  - 123
+  - abc
+```
+
+So, we can get YAML config equal to this XML one:
+
+``` xml
+<seq attr1="value1" attr2="value2">123</seq>
+<seq attr1="value1" attr2="value2">abc</seq>
+```
+
+## Implementation Details {#implementation-details}
+
+For each config file, the server also generates `file-preprocessed.xml` files when starting. These files contain all the completed substitutions and overrides, and they are intended for informational use. If ZooKeeper substitutions were used in the config files but ZooKeeper is not available on the server start, the server loads the configuration from the preprocessed file.
+
+The server tracks changes in config files, as well as files and ZooKeeper nodes that were used when performing substitutions and overrides, and reloads the settings for users and clusters on the fly. This means that you can modify the cluster, users, and their settings without restarting the server.
+
+[Original article](https://clickhouse.com/docs/en/operations/configuration-files/) <!--hide-->
diff --git a/docs/en/reference/operations/external-authenticators/index.md b/docs/en/reference/operations/external-authenticators/index.md
new file mode 100644
index 00000000000..af2ba713ec1
--- /dev/null
+++ b/docs/en/reference/operations/external-authenticators/index.md
@@ -0,0 +1,16 @@
+---
+sidebar_position: 48
+sidebar_label: External User Authenticators and Directories
+---
+
+# External User Authenticators and Directories 
+
+ClickHouse supports authenticating and managing users using external services.
+
+The following external authenticators and directories are supported:
+
+- [LDAP](./ldap.md#external-authenticators-ldap) [Authenticator](./ldap.md#ldap-external-authenticator) and [Directory](./ldap.md#ldap-external-user-directory)
+- Kerberos [Authenticator](./kerberos.md#external-authenticators-kerberos)
+- [SSL X.509 authentication](./ssl-x509.md#ssl-external-authentication)
+
+[Original article](https://clickhouse.com/docs/en/operations/external-authenticators/index/) <!--hide-->
diff --git a/docs/en/reference/operations/external-authenticators/kerberos.md b/docs/en/reference/operations/external-authenticators/kerberos.md
new file mode 100644
index 00000000000..3711bac79c3
--- /dev/null
+++ b/docs/en/reference/operations/external-authenticators/kerberos.md
@@ -0,0 +1,118 @@
+# Kerberos {#external-authenticators-kerberos}
+
+Existing and properly configured ClickHouse users can be authenticated via Kerberos authentication protocol.
+
+Currently, Kerberos can only be used as an external authenticator for existing users, which are defined in `users.xml` or in local access control paths. Those users may only use HTTP requests and must be able to authenticate using GSS-SPNEGO mechanism.
+
+For this approach, Kerberos must be configured in the system and must be enabled in ClickHouse config.
+
+
+## Enabling Kerberos in ClickHouse {#enabling-kerberos-in-clickhouse}
+
+To enable Kerberos, one should include `kerberos` section in `config.xml`. This section may contain additional parameters.
+
+#### Parameters:
+
+- `principal` - canonical service principal name that will be acquired and used when accepting security contexts.
+    - This parameter is optional, if omitted, the default principal will be used.
+
+
+- `realm` - a realm, that will be used to restrict authentication to only those requests whose initiator's realm matches it.
+    - This parameter is optional, if omitted, no additional filtering by realm will be applied.
+
+Example (goes into `config.xml`):
+
+```xml
+<clickhouse>
+    <!- ... -->
+    <kerberos />
+</clickhouse>
+```
+
+With principal specification:
+
+```xml
+<clickhouse>
+    <!- ... -->
+    <kerberos>
+        <principal>HTTP/clickhouse.example.com@EXAMPLE.COM</principal>
+    </kerberos>
+</clickhouse>
+```
+
+With filtering by realm:
+
+```xml
+<clickhouse>
+    <!- ... -->
+    <kerberos>
+        <realm>EXAMPLE.COM</realm>
+    </kerberos>
+</clickhouse>
+```
+
+:::warning
+You can define only one `kerberos` section. The presence of multiple `kerberos` sections will force ClickHouse to disable Kerberos authentication.
+:::
+
+:::warning
+`principal` and `realm` sections cannot be specified at the same time. The presence of both `principal` and `realm` sections will force ClickHouse to disable Kerberos authentication.
+:::
+
+## Kerberos as an external authenticator for existing users {#kerberos-as-an-external-authenticator-for-existing-users}
+
+Kerberos can be used as a method for verifying the identity of locally defined users (users defined in `users.xml` or in local access control paths). Currently, **only** requests over the HTTP interface can be *kerberized* (via GSS-SPNEGO mechanism).
+
+Kerberos principal name format usually follows this pattern:
+
+- *primary/instance@REALM*
+
+The */instance* part may occur zero or more times. **The *primary* part of the canonical principal name of the initiator is expected to match the kerberized user name for authentication to succeed**.
+
+### Enabling Kerberos in `users.xml` {#enabling-kerberos-in-users-xml}
+
+In order to enable Kerberos authentication for the user, specify `kerberos` section instead of `password` or similar sections in the user definition.
+
+Parameters:
+
+- `realm` - a realm that will be used to restrict authentication to only those requests whose initiator's realm matches it.
+    - This parameter is optional, if omitted, no additional filtering by realm will be applied.
+
+Example (goes into `users.xml`):
+
+```xml
+<clickhouse>
+    <!- ... -->
+    <users>
+        <!- ... -->
+        <my_user>
+            <!- ... -->
+            <kerberos>
+                <realm>EXAMPLE.COM</realm>
+            </kerberos>
+        </my_user>
+    </users>
+</clickhouse>
+```
+
+:::warning
+Note that Kerberos authentication cannot be used alongside with any other authentication mechanism. The presence of any other sections like `password` alongside `kerberos` will force ClickHouse to shutdown.
+:::
+
+:::info Reminder    
+Note, that now, once user `my_user` uses `kerberos`, Kerberos must be enabled in the main `config.xml` file as described previously.
+:::
+
+### Enabling Kerberos using SQL {#enabling-kerberos-using-sql}
+
+When [SQL-driven Access Control and Account Management](../access-rights.md#access-control) is enabled in ClickHouse, users identified by Kerberos can also be created using SQL statements.
+
+```sql
+CREATE USER my_user IDENTIFIED WITH kerberos REALM 'EXAMPLE.COM'
+```
+
+...or, without filtering by realm:
+
+```sql
+CREATE USER my_user IDENTIFIED WITH kerberos
+```
diff --git a/docs/en/reference/operations/external-authenticators/ldap.md b/docs/en/reference/operations/external-authenticators/ldap.md
new file mode 100644
index 00000000000..57e6ec1a087
--- /dev/null
+++ b/docs/en/reference/operations/external-authenticators/ldap.md
@@ -0,0 +1,182 @@
+# LDAP {#external-authenticators-ldap}
+
+LDAP server can be used to authenticate ClickHouse users. There are two different approaches for doing this:
+
+- Use LDAP as an external authenticator for existing users, which are defined in `users.xml` or in local access control paths.
+- Use LDAP as an external user directory and allow locally undefined users to be authenticated if they exist on the LDAP server.
+
+For both of these approaches, an internally named LDAP server must be defined in the ClickHouse config so that other parts of the config can refer to it.
+
+## LDAP Server Definition {#ldap-server-definition}
+
+To define LDAP server you must add `ldap_servers` section to the `config.xml`.
+
+**Example**
+
+```xml
+<clickhouse>
+    <!- ... -->
+    <ldap_servers>
+        <!- Typical LDAP server. -->
+        <my_ldap_server>
+            <host>localhost</host>
+            <port>636</port>
+            <bind_dn>uid={user_name},ou=users,dc=example,dc=com</bind_dn>
+            <verification_cooldown>300</verification_cooldown>
+            <enable_tls>yes</enable_tls>
+            <tls_minimum_protocol_version>tls1.2</tls_minimum_protocol_version>
+            <tls_require_cert>demand</tls_require_cert>
+            <tls_cert_file>/path/to/tls_cert_file</tls_cert_file>
+            <tls_key_file>/path/to/tls_key_file</tls_key_file>
+            <tls_ca_cert_file>/path/to/tls_ca_cert_file</tls_ca_cert_file>
+            <tls_ca_cert_dir>/path/to/tls_ca_cert_dir</tls_ca_cert_dir>
+            <tls_cipher_suite>ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:AES256-GCM-SHA384</tls_cipher_suite>
+        </my_ldap_server>
+
+        <!- Typical Active Directory with configured user DN detection for further role mapping. -->
+        <my_ad_server>
+            <host>localhost</host>
+            <port>389</port>
+            <bind_dn>EXAMPLE\{user_name}</bind_dn>
+            <user_dn_detection>
+                <base_dn>CN=Users,DC=example,DC=com</base_dn>
+                <search_filter>(&amp;(objectClass=user)(sAMAccountName={user_name}))</search_filter>
+            </user_dn_detection>
+            <enable_tls>no</enable_tls>
+        </my_ad_server>
+    </ldap_servers>
+</clickhouse>
+```
+
+Note, that you can define multiple LDAP servers inside the `ldap_servers` section using distinct names.
+
+**Parameters**
+
+- `host` — LDAP server hostname or IP, this parameter is mandatory and cannot be empty.
+- `port` — LDAP server port, default is `636` if `enable_tls` is set to `true`, `389` otherwise.
+- `bind_dn` — Template used to construct the DN to bind to.
+    - The resulting DN will be constructed by replacing all `{user_name}` substrings of the template with the actual user name during each authentication attempt.
+- `user_dn_detection` — Section with LDAP search parameters for detecting the actual user DN of the bound user.
+    - This is mainly used in search filters for further role mapping when the server is Active Directory. The resulting user DN will be used when replacing `{user_dn}` substrings wherever they are allowed. By default, user DN is set equal to bind DN, but once search is performed, it will be updated with to the actual detected user DN value.
+        - `base_dn` — Template used to construct the base DN for the LDAP search.
+            - The resulting DN will be constructed by replacing all `{user_name}` and `{bind_dn}` substrings of the template with the actual user name and bind DN during the LDAP search.
+        - `scope` — Scope of the LDAP search.
+            - Accepted values are: `base`, `one_level`, `children`, `subtree` (the default).
+        - `search_filter` — Template used to construct the search filter for the LDAP search.
+            - The resulting filter will be constructed by replacing all `{user_name}`, `{bind_dn}`, and `{base_dn}` substrings of the template with the actual user name, bind DN, and base DN during the LDAP search.
+            - Note, that the special characters must be escaped properly in XML.
+- `verification_cooldown` — A period of time, in seconds, after a successful bind attempt, during which the user will be assumed to be successfully authenticated for all consecutive requests without contacting the LDAP server.
+    - Specify `0` (the default) to disable caching and force contacting the LDAP server for each authentication request.
+- `enable_tls` — A flag to trigger the use of the secure connection to the LDAP server.
+    - Specify `no` for plain text `ldap://` protocol (not recommended).
+    - Specify `yes` for LDAP over SSL/TLS `ldaps://` protocol (recommended, the default).
+    - Specify `starttls` for legacy StartTLS protocol (plain text `ldap://` protocol, upgraded to TLS).
+- `tls_minimum_protocol_version` — The minimum protocol version of SSL/TLS.
+    - Accepted values are: `ssl2`, `ssl3`, `tls1.0`, `tls1.1`, `tls1.2` (the default).
+- `tls_require_cert` — SSL/TLS peer certificate verification behavior.
+    - Accepted values are: `never`, `allow`, `try`, `demand` (the default).
+- `tls_cert_file` — Path to certificate file.
+- `tls_key_file` — Path to certificate key file.
+- `tls_ca_cert_file` — Path to CA certificate file.
+- `tls_ca_cert_dir` — Path to the directory containing CA certificates.
+- `tls_cipher_suite` — Allowed cipher suite (in OpenSSL notation).
+
+## LDAP External Authenticator {#ldap-external-authenticator}
+
+A remote LDAP server can be used as a method for verifying passwords for locally defined users (users defined in `users.xml` or in local access control paths). To achieve this, specify previously defined LDAP server name instead of `password` or similar sections in the user definition.
+
+At each login attempt, ClickHouse tries to "bind" to the specified DN defined by the `bind_dn` parameter in the [LDAP server definition](#ldap-server-definition) using the provided credentials, and if successful, the user is considered authenticated. This is often called a "simple bind" method.
+
+**Example**
+
+```xml
+<clickhouse>
+    <!- ... -->
+    <users>
+        <!- ... -->
+        <my_user>
+            <!- ... -->
+            <ldap>
+                <server>my_ldap_server</server>
+            </ldap>
+        </my_user>
+    </users>
+</clickhouse>
+```
+
+Note, that user `my_user` refers to `my_ldap_server`. This LDAP server must be configured in the main `config.xml` file as described previously.
+
+When SQL-driven [Access Control and Account Management](../access-rights.md#access-control) is enabled, users that are authenticated by LDAP servers can also be created using the [CREATE USER](../../sql-reference/statements/create/user.md#create-user-statement) statement.
+
+Query:
+
+```sql
+CREATE USER my_user IDENTIFIED WITH ldap SERVER 'my_ldap_server';
+```
+
+## LDAP Exernal User Directory {#ldap-external-user-directory}
+
+In addition to the locally defined users, a remote LDAP server can be used as a source of user definitions. To achieve this, specify previously defined LDAP server name (see [LDAP Server Definition](#ldap-server-definition)) in the `ldap` section inside the `users_directories` section of the `config.xml` file.
+
+At each login attempt, ClickHouse tries to find the user definition locally and authenticate it as usual. If the user is not defined, ClickHouse will assume the definition exists in the external LDAP directory and will try to "bind" to the specified DN at the LDAP server using the provided credentials. If successful, the user will be considered existing and authenticated. The user will be assigned roles from the list specified in the `roles` section. Additionally, LDAP "search" can be performed and results can be transformed and treated as role names and then be assigned to the user if the `role_mapping` section is also configured. All this implies that the SQL-driven [Access Control and Account Management](../access-rights.md#access-control) is enabled and roles are created using the [CREATE ROLE](../../sql-reference/statements/create/role.md#create-role-statement) statement.
+
+**Example**
+
+Goes into `config.xml`.
+
+```xml
+<clickhouse>
+    <!- ... -->
+    <user_directories>
+        <!- Typical LDAP server. -->
+        <ldap>
+            <server>my_ldap_server</server>
+            <roles>
+                <my_local_role1 />
+                <my_local_role2 />
+            </roles>
+            <role_mapping>
+                <base_dn>ou=groups,dc=example,dc=com</base_dn>
+                <scope>subtree</scope>
+                <search_filter>(&amp;(objectClass=groupOfNames)(member={bind_dn}))</search_filter>
+                <attribute>cn</attribute>
+                <prefix>clickhouse_</prefix>
+            </role_mapping>
+        </ldap>
+
+        <!- Typical Active Directory with role mapping that relies on the detected user DN. -->
+        <ldap>
+            <server>my_ad_server</server>
+            <role_mapping>
+                <base_dn>CN=Users,DC=example,DC=com</base_dn>
+                <attribute>CN</attribute>
+                <scope>subtree</scope>
+                <search_filter>(&amp;(objectClass=group)(member={user_dn}))</search_filter>
+                <prefix>clickhouse_</prefix>
+            </role_mapping>
+        </ldap>
+    </user_directories>
+</clickhouse>
+```
+
+Note that `my_ldap_server` referred in the `ldap` section inside the `user_directories` section must be a previously defined LDAP server that is configured in the `config.xml` (see [LDAP Server Definition](#ldap-server-definition)).
+
+**Parameters**
+
+- `server` — One of LDAP server names defined in the `ldap_servers` config section above. This parameter is mandatory and cannot be empty.
+- `roles` — Section with a list of locally defined roles that will be assigned to each user retrieved from the LDAP server.
+    - If no roles are specified here or assigned during role mapping (below), user will not be able to perform any actions after authentication.
+- `role_mapping` — Section with LDAP search parameters and mapping rules.
+    - When a user authenticates, while still bound to LDAP, an LDAP search is performed using `search_filter` and the name of the logged-in user. For each entry found during that search, the value of the specified attribute is extracted. For each attribute value that has the specified prefix, the prefix is removed, and the rest of the value becomes the name of a local role defined in ClickHouse, which is expected to be created beforehand by the [CREATE ROLE](../../sql-reference/statements/create/role.md#create-role-statement) statement.
+    - There can be multiple `role_mapping` sections defined inside the same `ldap` section. All of them will be applied.
+        - `base_dn` — Template used to construct the base DN for the LDAP search.
+            - The resulting DN will be constructed by replacing all `{user_name}`, `{bind_dn}`, and `{user_dn}` substrings of the template with the actual user name, bind DN, and user DN during each LDAP search.
+        - `scope` — Scope of the LDAP search.
+            - Accepted values are: `base`, `one_level`, `children`, `subtree` (the default).
+        - `search_filter` — Template used to construct the search filter for the LDAP search.
+            - The resulting filter will be constructed by replacing all `{user_name}`, `{bind_dn}`, `{user_dn}`, and `{base_dn}` substrings of the template with the actual user name, bind DN, user DN, and base DN during each LDAP search.
+            - Note, that the special characters must be escaped properly in XML.
+        - `attribute` — Attribute name whose values will be returned by the LDAP search. `cn`, by default.
+        - `prefix` — Prefix, that will be expected to be in front of each string in the original list of strings returned by the LDAP search. The prefix will be removed from the original strings and the resulting strings will be treated as local role names. Empty by default.
+
+[Original article](https://clickhouse.com/docs/en/operations/external-authenticators/ldap/) <!--hide-->
diff --git a/docs/en/reference/operations/external-authenticators/ssl-x509.md b/docs/en/reference/operations/external-authenticators/ssl-x509.md
new file mode 100644
index 00000000000..dd4f35257bb
--- /dev/null
+++ b/docs/en/reference/operations/external-authenticators/ssl-x509.md
@@ -0,0 +1,24 @@
+# SSL X.509 certificate authentication {#ssl-external-authentication}
+
+[SSL 'strict' option](../server-configuration-parameters/settings.md#server_configuration_parameters-openssl) enables mandatory certificate validation for the incoming connections. In this case, only connections with trusted certificates can be established. Connections with untrusted certificates will be rejected. Thus, certificate validation allows to uniquely authenticate an incoming connection. `Common Name` field of the certificate is used to identify connected user. This allows to associate multiple certificates with the same user. Additionally, reissuing and revoking of the certificates does not affect the ClickHouse configuration.
+
+To enable SSL certificate authentication, a list of `Common Name`'s for each ClickHouse user must be sspecified in the settings file `config.xml `:
+
+**Example**
+```xml
+<clickhouse>
+    <!- ... -->
+    <users>
+        <user_name>
+            <certificates>
+                <common_name>host.domain.com:example_user</common_name>
+                <common_name>host.domain.com:example_user_dev</common_name>
+                <!-- More names -->
+            </certificates>
+            <!-- Other settings -->
+        </user_name>
+    </users>
+</clickhouse>
+```
+
+For the SSL [`chain of trust`](https://en.wikipedia.org/wiki/Chain_of_trust) to work correctly, it is also important to make sure that the [`caConfig`](../server-configuration-parameters/settings.md#server_configuration_parameters-openssl) parameter is configured properly.
\ No newline at end of file
diff --git a/docs/en/reference/operations/index.md b/docs/en/reference/operations/index.md
new file mode 100644
index 00000000000..824e851e997
--- /dev/null
+++ b/docs/en/reference/operations/index.md
@@ -0,0 +1,25 @@
+---
+sidebar_position: 41
+sidebar_label: Operations
+---
+
+# Operations {#operations}
+
+ClickHouse operations manual consists of the following major sections:
+
+-   [Requirements](../operations/requirements.md)
+-   [Monitoring](../operations/monitoring.md)
+-   [Troubleshooting](../operations/troubleshooting.md)
+-   [Usage Recommendations](../operations/tips.md)
+-   [Update Procedure](../operations/update.md)
+-   [Access Rights](../operations/access-rights.md)
+-   [Data Backup](../operations/backup.md)
+-   [Configuration Files](../operations/configuration-files.md)
+-   [Quotas](../operations/quotas.md)
+-   [System Tables](../operations/system-tables/index.md)
+-   [Server Configuration Parameters](../operations/server-configuration-parameters/index.md)
+-   [How To Test Your Hardware With ClickHouse](../operations/performance-test.md)
+-   [Settings](../operations/settings/index.md)
+-   [Utilities](../operations/utilities/index.md)
+
+[Original article](https://clickhouse.com/docs/en/operations/)
diff --git a/docs/en/reference/operations/monitoring.md b/docs/en/reference/operations/monitoring.md
new file mode 100644
index 00000000000..437122e106d
--- /dev/null
+++ b/docs/en/reference/operations/monitoring.md
@@ -0,0 +1,44 @@
+---
+sidebar_position: 45
+sidebar_label: Monitoring
+---
+
+# Monitoring {#monitoring}
+
+You can monitor:
+
+-   Utilization of hardware resources.
+-   ClickHouse server metrics.
+
+## Resource Utilization {#resource-utilization}
+
+ClickHouse does not monitor the state of hardware resources by itself.
+
+It is highly recommended to set up monitoring for:
+
+-   Load and temperature on processors.
+
+    You can use [dmesg](https://en.wikipedia.org/wiki/Dmesg), [turbostat](https://www.linux.org/docs/man8/turbostat.html) or other instruments.
+
+-   Utilization of storage system, RAM and network.
+
+## ClickHouse Server Metrics {#clickhouse-server-metrics}
+
+ClickHouse server has embedded instruments for self-state monitoring.
+
+To track server events use server logs. See the [logger](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-logger) section of the configuration file.
+
+ClickHouse collects:
+
+-   Different metrics of how the server uses computational resources.
+-   Common statistics on query processing.
+
+You can find metrics in the [system.metrics](../operations/system-tables/metrics.md#system_tables-metrics), [system.events](../operations/system-tables/events.md#system_tables-events), and [system.asynchronous_metrics](../operations/system-tables/asynchronous_metrics.md#system_tables-asynchronous_metrics) tables.
+
+You can configure ClickHouse to export metrics to [Graphite](https://github.com/graphite-project). See the [Graphite section](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-graphite) in the ClickHouse server configuration file. Before configuring export of metrics, you should set up Graphite by following their official [guide](https://graphite.readthedocs.io/en/latest/install.html).
+
+You can configure ClickHouse to export metrics to [Prometheus](https://prometheus.io). See the [Prometheus section](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-prometheus) in the ClickHouse server configuration file. Before configuring export of metrics, you should set up Prometheus by following their official [guide](https://prometheus.io/docs/prometheus/latest/installation/).
+
+Additionally, you can monitor server availability through the HTTP API. Send the `HTTP GET` request to `/ping`. If the server is available, it responds with `200 OK`.
+
+To monitor servers in a cluster configuration, you should set the [max_replica_delay_for_distributed_queries](../operations/settings/settings.md#settings-max_replica_delay_for_distributed_queries) parameter and use the HTTP resource `/replicas_status`. A request to `/replicas_status` returns `200 OK` if the replica is available and is not delayed behind the other replicas. If a replica is delayed, it returns `503 HTTP_SERVICE_UNAVAILABLE` with information about the gap.
diff --git a/docs/en/reference/operations/named-collections.md b/docs/en/reference/operations/named-collections.md
new file mode 100644
index 00000000000..52520ba76b7
--- /dev/null
+++ b/docs/en/reference/operations/named-collections.md
@@ -0,0 +1,230 @@
+---
+sidebar_position: 69
+sidebar_label: "Named connections"
+---
+
+# Storing details for connecting to external sources in configuration files  {#named-collections}
+
+Details for connecting to external sources (dictionaries, tables, table functions) can be saved
+in configuration files and thus simplify the creation of objects and hide credentials
+from users with only SQL access.
+
+Parameters can be set in XML `<format>CSV</format>` and overridden in SQL `, format = 'TSV'`.
+The parameters in SQL can be overridden using format `key` = `value`: `compression_method = 'gzip'`.
+
+Named connections are stored in the `config.xml` file of the ClickHouse server in the `<named_collections>` section and are applied when ClickHouse starts.
+
+Example of configuration:
+```xml
+$ cat /etc/clickhouse-server/config.d/named_collections.xml
+<clickhouse>
+     <named_collections>
+     ...
+     </named_collections>
+</clickhouse>
+```
+
+## Named connections for accessing S3.
+
+The description of parameters see [s3 Table Function](../sql-reference/table-functions/s3.md).
+
+Example of configuration:
+```xml
+<clickhouse>
+    <named_collections>
+        <s3_mydata>
+            <access_key_id>AKIAIOSFODNN7EXAMPLE</access_key_id>
+            <secret_access_key> wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY</secret_access_key>
+            <format>CSV</format>
+            <url>https://s3.us-east-1.amazonaws.com/yourbucket/mydata/</url>
+        </s3_mydata>
+    </named_collections>
+</clickhouse>
+```
+
+### Example of using named connections with the s3 function
+
+```sql
+INSERT INTO FUNCTION s3(s3_mydata, filename = 'test_file.tsv.gz',
+   format = 'TSV', structure = 'number UInt64', compression_method = 'gzip')
+SELECT * FROM numbers(10000);
+
+SELECT count()
+FROM s3(s3_mydata, filename = 'test_file.tsv.gz')
+
+┌─count()─┐
+│   10000 │
+└─────────┘
+1 rows in set. Elapsed: 0.279 sec. Processed 10.00 thousand rows, 90.00 KB (35.78 thousand rows/s., 322.02 KB/s.)
+```
+
+### Example of using named connections with an S3 table
+
+```sql
+CREATE TABLE s3_engine_table (number Int64)
+ENGINE=S3(s3_mydata, url='https://s3.us-east-1.amazonaws.com/yourbucket/mydata/test_file.tsv.gz', format = 'TSV')
+SETTINGS input_format_with_names_use_header = 0;
+
+SELECT * FROM s3_engine_table LIMIT 3;
+┌─number─┐
+│      0 │
+│      1 │
+│      2 │
+└────────┘
+```
+
+## Named connections for accessing MySQL database
+
+The description of parameters see [mysql](../sql-reference/table-functions/mysql.md).
+
+Example of configuration:
+```xml
+<clickhouse>
+    <named_collections>
+        <mymysql>
+            <user>myuser</user>
+            <password>mypass</password>
+            <host>127.0.0.1</host>
+            <port>3306</port>
+            <database>test</database>
+            <connection_pool_size>8</connection_pool_size>
+            <on_duplicate_clause>1</on_duplicate_clause>
+            <replace_query>1</replace_query>
+        </mymysql>
+    </named_collections>
+</clickhouse>
+```
+
+### Example of using named connections with the mysql function
+
+```sql
+SELECT count() FROM mysql(mymysql, table = 'test');
+
+┌─count()─┐
+│       3 │
+└─────────┘
+```
+
+### Example of using named connections with an MySQL table
+
+```sql
+CREATE TABLE mytable(A Int64) ENGINE = MySQL(mymysql, table = 'test', connection_pool_size=3, replace_query=0);
+SELECT count() FROM mytable;
+
+┌─count()─┐
+│       3 │
+└─────────┘
+```
+
+### Example of using named connections with database with engine MySQL
+
+```sql
+CREATE DATABASE mydatabase ENGINE = MySQL(mymysql);
+
+SHOW TABLES FROM mydatabase;
+
+┌─name───┐
+│ source │
+│ test   │
+└────────┘
+```
+
+### Example of using named connections with an external dictionary with source MySQL
+
+```sql
+CREATE DICTIONARY dict (A Int64, B String)
+PRIMARY KEY A
+SOURCE(MYSQL(NAME mymysql TABLE 'source'))
+LIFETIME(MIN 1 MAX 2)
+LAYOUT(HASHED());
+
+SELECT dictGet('dict', 'B', 2);
+
+┌─dictGet('dict', 'B', 2)─┐
+│ two                     │
+└─────────────────────────┘
+```
+
+## Named connections for accessing PostgreSQL database
+
+The description of parameters see [postgresql](../sql-reference/table-functions/postgresql.md).
+
+Example of configuration:
+```xml
+<clickhouse>
+    <named_collections>
+        <mypg>
+            <user>pguser</user>
+            <password>jw8s0F4</password>
+            <host>127.0.0.1</host>
+            <port>5432</port>
+            <database>test</database>
+            <schema>test_schema</schema>
+            <connection_pool_size>8</connection_pool_size>
+        </mypg>
+    </named_collections>
+</clickhouse>
+```
+
+### Example of using named connections with the postgresql function
+
+```sql
+SELECT * FROM postgresql(mypg, table = 'test');
+
+┌─a─┬─b───┐
+│ 2 │ two │
+│ 1 │ one │
+└───┴─────┘
+
+
+SELECT * FROM postgresql(mypg, table = 'test', schema = 'public');
+
+┌─a─┐
+│ 1 │
+│ 2 │
+│ 3 │
+└───┘
+```
+
+
+### Example of using named connections with database with engine PostgreSQL
+
+```sql
+CREATE TABLE mypgtable (a Int64) ENGINE = PostgreSQL(mypg, table = 'test', schema = 'public');
+
+SELECT * FROM mypgtable;
+
+┌─a─┐
+│ 1 │
+│ 2 │
+│ 3 │
+└───┘
+```
+
+### Example of using named connections with database with engine PostgreSQL
+
+```sql
+CREATE DATABASE mydatabase ENGINE = PostgreSQL(mypg);
+
+SHOW TABLES FROM mydatabase
+
+┌─name─┐
+│ test │
+└──────┘
+```
+
+### Example of using named connections with an external dictionary with source POSTGRESQL
+
+```sql
+CREATE DICTIONARY dict (a Int64, b String)
+PRIMARY KEY a
+SOURCE(POSTGRESQL(NAME mypg TABLE test))
+LIFETIME(MIN 1 MAX 2)
+LAYOUT(HASHED());
+
+SELECT dictGet('dict', 'b', 2);
+
+┌─dictGet('dict', 'b', 2)─┐
+│ two                     │
+└─────────────────────────┘
+```
\ No newline at end of file
diff --git a/docs/en/reference/operations/opentelemetry.md b/docs/en/reference/operations/opentelemetry.md
new file mode 100644
index 00000000000..740537d88bc
--- /dev/null
+++ b/docs/en/reference/operations/opentelemetry.md
@@ -0,0 +1,65 @@
+---
+sidebar_position: 62
+sidebar_label: OpenTelemetry Support
+---
+
+# [experimental] OpenTelemetry Support
+
+[OpenTelemetry](https://opentelemetry.io/) is an open standard for collecting traces and metrics from the distributed application. ClickHouse has some support for OpenTelemetry.
+
+:::warning    
+This is an experimental feature that will change in backwards-incompatible ways in future releases.
+:::
+
+## Supplying Trace Context to ClickHouse
+
+ClickHouse accepts trace context HTTP headers, as described by the [W3C recommendation](https://www.w3.org/TR/trace-context/). It also accepts trace context over a native protocol that is used for communication between ClickHouse servers or between the client and server. For manual testing, trace context headers conforming to the Trace Context recommendation can be supplied to `clickhouse-client` using `--opentelemetry-traceparent` and `--opentelemetry-tracestate` flags.
+
+If no parent trace context is supplied or the provided trace context does not comply with W3C standard above, ClickHouse can start a new trace, with probability controlled by the [opentelemetry_start_trace_probability](../operations/settings/settings.md#opentelemetry-start-trace-probability) setting.
+
+## Propagating the Trace Context
+
+The trace context is propagated to downstream services in the following cases:
+
+* Queries to remote ClickHouse servers, such as when using [Distributed](../engines/table-engines/special/distributed.md) table engine.
+
+* [url](../sql-reference/table-functions/url.md) table function. Trace context information is sent in HTTP headers.
+
+## Tracing the ClickHouse Itself
+
+ClickHouse creates `trace spans` for each query and some of the query execution stages, such as query planning or distributed queries.
+
+To be useful, the tracing information has to be exported to a monitoring system that supports OpenTelemetry, such as [Jaeger](https://jaegertracing.io/) or [Prometheus](https://prometheus.io/). ClickHouse avoids a dependency on a particular monitoring system, instead only providing the tracing data through a system table. OpenTelemetry trace span information [required by the standard](https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/overview.md#span) is stored in the [system.opentelemetry_span_log](../operations/system-tables/opentelemetry_span_log.md) table.
+
+The table must be enabled in the server configuration, see the `opentelemetry_span_log` element in the default config file `config.xml`. It is enabled by default.
+
+The tags or attributes are saved as two parallel arrays, containing the keys and values. Use [ARRAY JOIN](../sql-reference/statements/select/array-join.md) to work with them.
+
+## Integration with monitoring systems
+
+At the moment, there is no ready tool that can export the tracing data from ClickHouse to a monitoring system.
+
+For testing, it is possible to setup the export using a materialized view with the [URL](../engines/table-engines/special/url.md) engine over the [system.opentelemetry_span_log](../operations/system-tables/opentelemetry_span_log.md) table, which would push the arriving log data to an HTTP endpoint of a trace collector. For example, to push the minimal span data to a Zipkin instance running at `http://localhost:9411`, in Zipkin v2 JSON format:
+
+```sql
+CREATE MATERIALIZED VIEW default.zipkin_spans
+ENGINE = URL('http://127.0.0.1:9411/api/v2/spans', 'JSONEachRow')
+SETTINGS output_format_json_named_tuples_as_objects = 1,
+    output_format_json_array_of_rows = 1 AS
+SELECT
+    lower(hex(trace_id)) AS traceId,
+    case when parent_span_id = 0 then '' else lower(hex(parent_span_id)) end AS parentId,
+    lower(hex(span_id)) AS id,
+    operation_name AS name,
+    start_time_us AS timestamp,
+    finish_time_us - start_time_us AS duration,
+    cast(tuple('clickhouse'), 'Tuple(serviceName text)') AS localEndpoint,
+    cast(tuple(
+        attribute.values[indexOf(attribute.names, 'db.statement')]),
+        'Tuple("db.statement" text)') AS tags
+FROM system.opentelemetry_span_log
+```
+
+In case of any errors, the part of the log data for which the error has occurred will be silently lost. Check the server log for error messages if the data does not arrive.
+
+[Original article](https://clickhouse.com/docs/en/operations/opentelemetry/) <!--hide-->
diff --git a/docs/en/reference/operations/optimizing-performance/index.md b/docs/en/reference/operations/optimizing-performance/index.md
new file mode 100644
index 00000000000..ef9c6a4b664
--- /dev/null
+++ b/docs/en/reference/operations/optimizing-performance/index.md
@@ -0,0 +1,8 @@
+---
+sidebar_label: Optimizing Performance
+sidebar_position: 52
+---
+
+# Optimizing Performance {#optimizing-performance}
+
+-   [Sampling query profiler](../../operations/optimizing-performance/sampling-query-profiler.md)
diff --git a/docs/en/reference/operations/optimizing-performance/sampling-query-profiler.md b/docs/en/reference/operations/optimizing-performance/sampling-query-profiler.md
new file mode 100644
index 00000000000..39e83545506
--- /dev/null
+++ b/docs/en/reference/operations/optimizing-performance/sampling-query-profiler.md
@@ -0,0 +1,62 @@
+---
+sidebar_position: 54
+sidebar_label: Query Profiling
+---
+
+# Sampling Query Profiler {#sampling-query-profiler}
+
+ClickHouse runs sampling profiler that allows analyzing query execution. Using profiler you can find source code routines that used the most frequently during query execution. You can trace CPU time and wall-clock time spent including idle time.
+
+To use profiler:
+
+-   Setup the [trace_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-trace_log) section of the server configuration.
+
+    This section configures the [trace_log](../../operations/system-tables/trace_log.md#system_tables-trace_log) system table containing the results of the profiler functioning. It is configured by default. Remember that data in this table is valid only for a running server. After the server restart, ClickHouse does not clean up the table and all the stored virtual memory address may become invalid.
+
+-   Setup the [query_profiler_cpu_time_period_ns](../../operations/settings/settings.md#query_profiler_cpu_time_period_ns) or [query_profiler_real_time_period_ns](../../operations/settings/settings.md#query_profiler_real_time_period_ns) settings. Both settings can be used simultaneously.
+
+    These settings allow you to configure profiler timers. As these are the session settings, you can get different sampling frequency for the whole server, individual users or user profiles, for your interactive session, and for each individual query.
+
+The default sampling frequency is one sample per second and both CPU and real timers are enabled. This frequency allows collecting enough information about ClickHouse cluster. At the same time, working with this frequency, profiler does not affect ClickHouse server’s performance. If you need to profile each individual query try to use higher sampling frequency.
+
+To analyze the `trace_log` system table:
+
+-   Install the `clickhouse-common-static-dbg` package. See [Install from DEB Packages](../../install.md#install-from-deb-packages).
+
+-   Allow introspection functions by the [allow_introspection_functions](../../operations/settings/settings.md#settings-allow_introspection_functions) setting.
+
+    For security reasons, introspection functions are disabled by default.
+
+-   Use the `addressToLine`, `addressToLineWithInlines`, `addressToSymbol` and `demangle` [introspection functions](../../sql-reference/functions/introspection.md) to get function names and their positions in ClickHouse code. To get a profile for some query, you need to aggregate data from the `trace_log` table. You can aggregate data by individual functions or by the whole stack traces.
+
+If you need to visualize `trace_log` info, try [flamegraph](../../interfaces/third-party/gui/#clickhouse-flamegraph) and [speedscope](https://github.com/laplab/clickhouse-speedscope).
+
+## Example {#example}
+
+In this example we:
+
+-   Filtering `trace_log` data by a query identifier and the current date.
+
+-   Aggregating by stack trace.
+
+-   Using introspection functions, we will get a report of:
+
+    -   Names of symbols and corresponding source code functions.
+    -   Source code locations of these functions.
+
+<!-- -->
+
+``` sql
+SELECT
+    count(),
+    arrayStringConcat(arrayMap(x -> concat(demangle(addressToSymbol(x)), '\n    ', addressToLine(x)), trace), '\n') AS sym
+FROM system.trace_log
+WHERE (query_id = 'ebca3574-ad0a-400a-9cbc-dca382f5998c') AND (event_date = today())
+GROUP BY trace
+ORDER BY count() DESC
+LIMIT 10
+```
+
+``` text
+{% include "examples/sampling_query_profiler_result.txt" %}
+```
diff --git a/docs/en/reference/operations/performance-test.md b/docs/en/reference/operations/performance-test.md
new file mode 100644
index 00000000000..0ba3a9908a5
--- /dev/null
+++ b/docs/en/reference/operations/performance-test.md
@@ -0,0 +1,83 @@
+---
+sidebar_position: 54
+sidebar_label: Testing Hardware
+---
+
+# How to Test Your Hardware with ClickHouse {#how-to-test-your-hardware-with-clickhouse}
+
+You can run basic ClickHouse performance test on any server without installation of ClickHouse packages.
+
+
+## Automated Run
+
+You can run benchmark with a single script.
+
+1. Download the script.
+```
+wget https://raw.githubusercontent.com/ClickHouse/ClickHouse/master/benchmark/hardware.sh
+```
+
+2. Run the script.
+```
+chmod a+x ./hardware.sh
+./hardware.sh
+```
+
+3. Copy the output and send it to feedback@clickhouse.com
+
+All the results are published here: https://clickhouse.com/benchmark/hardware/
+
+
+## Manual Run
+
+Alternatively you can perform benchmark in the following steps.
+
+1.  ssh to the server and download the binary with wget:
+```bash
+# For amd64:
+wget https://builds.clickhouse.com/master/amd64/clickhouse
+# For aarch64:
+wget https://builds.clickhouse.com/master/aarch64/clickhouse
+# For powerpc64le:
+wget https://builds.clickhouse.com/master/powerpc64le/clickhouse
+# For freebsd:
+wget https://builds.clickhouse.com/master/freebsd/clickhouse
+# For freebsd-aarch64:
+wget https://builds.clickhouse.com/master/freebsd-aarch64/clickhouse
+# For freebsd-powerpc64le:
+wget https://builds.clickhouse.com/master/freebsd-powerpc64le/clickhouse
+# For macos:
+wget https://builds.clickhouse.com/master/macos/clickhouse
+# For macos-aarch64:
+wget https://builds.clickhouse.com/master/macos-aarch64/clickhouse
+# Then do:
+chmod a+x clickhouse
+```
+2.  Download benchmark files:
+```bash
+wget https://raw.githubusercontent.com/ClickHouse/ClickHouse/master/benchmark/clickhouse/benchmark-new.sh
+chmod a+x benchmark-new.sh
+wget https://raw.githubusercontent.com/ClickHouse/ClickHouse/master/benchmark/clickhouse/queries.sql
+```
+3.  Download the [web analytics dataset](../example-datasets/metrica.md) (“hits” table containing 100 million rows).
+```bash
+wget https://datasets.clickhouse.com/hits/partitions/hits_100m_obfuscated_v1.tar.xz
+tar xvf hits_100m_obfuscated_v1.tar.xz -C .
+mv hits_100m_obfuscated_v1/* .
+```
+4.  Run the server:
+```bash
+./clickhouse server
+```
+5.  Check the data: ssh to the server in another terminal
+```bash
+./clickhouse client --query "SELECT count() FROM hits_100m_obfuscated"
+100000000
+```
+6.  Run the benchmark:
+```bash
+./benchmark-new.sh hits_100m_obfuscated
+```
+7.  Send the numbers and the info about your hardware configuration to feedback@clickhouse.com
+
+All the results are published here: https://clickhouse.com/benchmark/hardware/
diff --git a/docs/en/reference/operations/quotas.md b/docs/en/reference/operations/quotas.md
new file mode 100644
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--- /dev/null
+++ b/docs/en/reference/operations/quotas.md
@@ -0,0 +1,120 @@
+---
+sidebar_position: 51
+sidebar_label: Quotas
+---
+
+# Quotas {#quotas}
+
+Quotas allow you to limit resource usage over a period of time or track the use of resources.
+Quotas are set up in the user config, which is usually ‘users.xml’.
+
+The system also has a feature for limiting the complexity of a single query. See the section [Restrictions on query complexity](../operations/settings/query-complexity.md).
+
+In contrast to query complexity restrictions, quotas:
+
+-   Place restrictions on a set of queries that can be run over a period of time, instead of limiting a single query.
+-   Account for resources spent on all remote servers for distributed query processing.
+
+Let’s look at the section of the ‘users.xml’ file that defines quotas.
+
+``` xml
+<!-- Quotas -->
+<quotas>
+    <!-- Quota name. -->
+    <default>
+        <!-- Restrictions for a time period. You can set many intervals with different restrictions. -->
+        <interval>
+            <!-- Length of the interval. -->
+            <duration>3600</duration>
+
+            <!-- Unlimited. Just collect data for the specified time interval. -->
+            <queries>0</queries>
+            <query_selects>0</query_selects>
+            <query_inserts>0</query_inserts>
+            <errors>0</errors>
+            <result_rows>0</result_rows>
+            <read_rows>0</read_rows>
+            <execution_time>0</execution_time>
+        </interval>
+    </default>
+```
+
+By default, the quota tracks resource consumption for each hour, without limiting usage.
+The resource consumption calculated for each interval is output to the server log after each request.
+
+``` xml
+<statbox>
+    <!-- Restrictions for a time period. You can set many intervals with different restrictions. -->
+    <interval>
+        <!-- Length of the interval. -->
+        <duration>3600</duration>
+
+        <queries>1000</queries>
+        <query_selects>100</query_selects>
+        <query_inserts>100</query_inserts>
+        <errors>100</errors>
+        <result_rows>1000000000</result_rows>
+        <read_rows>100000000000</read_rows>
+        <execution_time>900</execution_time>
+    </interval>
+
+    <interval>
+        <duration>86400</duration>
+
+        <queries>10000</queries>
+        <query_selects>10000</query_selects>
+        <query_inserts>10000</query_inserts>
+        <errors>1000</errors>
+        <result_rows>5000000000</result_rows>
+        <read_rows>500000000000</read_rows>
+        <execution_time>7200</execution_time>
+    </interval>
+</statbox>
+```
+
+For the ‘statbox’ quota, restrictions are set for every hour and for every 24 hours (86,400 seconds). The time interval is counted, starting from an implementation-defined fixed moment in time. In other words, the 24-hour interval does not necessarily begin at midnight.
+
+When the interval ends, all collected values are cleared. For the next hour, the quota calculation starts over.
+
+Here are the amounts that can be restricted:
+
+`queries` – The total number of requests.
+
+`query_selects` – The total number of select requests.
+
+`query_inserts` – The total number of insert requests.
+
+`errors` – The number of queries that threw an exception.
+
+`result_rows` – The total number of rows given as a result.
+
+`read_rows` – The total number of source rows read from tables for running the query on all remote servers.
+
+`execution_time` – The total query execution time, in seconds (wall time).
+
+If the limit is exceeded for at least one time interval, an exception is thrown with a text about which restriction was exceeded, for which interval, and when the new interval begins (when queries can be sent again).
+
+Quotas can use the “quota key” feature to report on resources for multiple keys independently. Here is an example of this:
+
+``` xml
+<!-- For the global reports designer. -->
+<web_global>
+    <!-- keyed – The quota_key "key" is passed in the query parameter,
+            and the quota is tracked separately for each key value.
+        For example, you can pass a username as the key,
+            so the quota will be counted separately for each username.
+        Using keys makes sense only if quota_key is transmitted by the program, not by a user.
+
+        You can also write <keyed_by_ip />, so the IP address is used as the quota key.
+        (But keep in mind that users can change the IPv6 address fairly easily.)
+    -->
+    <keyed />
+```
+
+The quota is assigned to users in the ‘users’ section of the config. See the section “Access rights”.
+
+For distributed query processing, the accumulated amounts are stored on the requestor server. So if the user goes to another server, the quota there will “start over”.
+
+When the server is restarted, quotas are reset.
+
+[Original article](https://clickhouse.com/docs/en/operations/quotas/) <!--hide-->
diff --git a/docs/en/reference/operations/requirements.md b/docs/en/reference/operations/requirements.md
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+---
+sidebar_position: 44
+sidebar_label: Requirements
+---
+
+# Requirements 
+
+## CPU {#cpu}
+
+For installation from prebuilt deb packages, use a CPU with x86_64 architecture and support for SSE 4.2 instructions. To run ClickHouse with processors that do not support SSE 4.2 or have AArch64 or PowerPC64LE architecture, you should build ClickHouse from sources.
+
+ClickHouse implements parallel data processing and uses all the hardware resources available. When choosing a processor, take into account that ClickHouse works more efficiently at configurations with a large number of cores but a lower clock rate than at configurations with fewer cores and a higher clock rate. For example, 16 cores with 2600 MHz is preferable to 8 cores with 3600 MHz.
+
+It is recommended to use **Turbo Boost** and **hyper-threading** technologies. It significantly improves performance with a typical workload.
+
+## RAM {#ram}
+
+We recommend using a minimum of 4GB of RAM to perform non-trivial queries. The ClickHouse server can run with a much smaller amount of RAM, but it requires memory for processing queries.
+
+The required volume of RAM depends on:
+
+-   The complexity of queries.
+-   The amount of data that is processed in queries.
+
+To calculate the required volume of RAM, you should estimate the size of temporary data for [GROUP BY](../sql-reference/statements/select/group-by.md#select-group-by-clause), [DISTINCT](../sql-reference/statements/select/distinct.md#select-distinct), [JOIN](../sql-reference/statements/select/join.md#select-join) and other operations you use.
+
+ClickHouse can use external memory for temporary data. See [GROUP BY in External Memory](../sql-reference/statements/select/group-by.md#select-group-by-in-external-memory) for details.
+
+## Swap File {#swap-file}
+
+Disable the swap file for production environments.
+
+## Storage Subsystem {#storage-subsystem}
+
+You need to have 2GB of free disk space to install ClickHouse.
+
+The volume of storage required for your data should be calculated separately. Assessment should include:
+
+-   Estimation of the data volume.
+
+    You can take a sample of the data and get the average size of a row from it. Then multiply the value by the number of rows you plan to store.
+
+-   The data compression coefficient.
+
+    To estimate the data compression coefficient, load a sample of your data into ClickHouse, and compare the actual size of the data with the size of the table stored. For example, clickstream data is usually compressed by 6-10 times.
+
+To calculate the final volume of data to be stored, apply the compression coefficient to the estimated data volume. If you plan to store data in several replicas, then multiply the estimated volume by the number of replicas.
+
+## Network {#network}
+
+If possible, use networks of 10G or higher class.
+
+The network bandwidth is critical for processing distributed queries with a large amount of intermediate data. Besides, network speed affects replication processes.
+
+## Software {#software}
+
+ClickHouse is developed primarily for the Linux family of operating systems. The recommended Linux distribution is Ubuntu. The `tzdata` package should be installed in the system.
+
+ClickHouse can also work in other operating system families. See details in the [install guide](../install.md) section of the documentation.
diff --git a/docs/en/reference/operations/server-configuration-parameters/index.md b/docs/en/reference/operations/server-configuration-parameters/index.md
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+---
+sidebar_position: 54
+sidebar_label: Server Configuration Parameters
+---
+
+# Server Configuration Parameters 
+
+This section contains descriptions of server settings that cannot be changed at the session or query level.
+
+These settings are stored in the `config.xml` file on the ClickHouse server.
+
+Other settings are described in the “[Settings](../../operations/settings/index.md#session-settings-intro)” section.
+
+Before studying the settings, read the [Configuration files](../../operations/configuration-files.md#configuration_files) section and note the use of substitutions (the `incl` and `optional` attributes).
+
+[Original article](https://clickhouse.com/docs/en/operations/server_configuration_parameters/) <!--hide-->
diff --git a/docs/en/reference/operations/server-configuration-parameters/settings.md b/docs/en/reference/operations/server-configuration-parameters/settings.md
new file mode 100644
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+++ b/docs/en/reference/operations/server-configuration-parameters/settings.md
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+---
+sidebar_position: 57
+sidebar_label: Server Settings
+---
+
+# Server Settings {#server-settings}
+
+## builtin_dictionaries_reload_interval {#builtin-dictionaries-reload-interval}
+
+The interval in seconds before reloading built-in dictionaries.
+
+ClickHouse reloads built-in dictionaries every x seconds. This makes it possible to edit dictionaries “on the fly” without restarting the server.
+
+Default value: 3600.
+
+**Example**
+
+``` xml
+<builtin_dictionaries_reload_interval>3600</builtin_dictionaries_reload_interval>
+```
+
+## compression {#server-settings-compression}
+
+Data compression settings for [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md)-engine tables.
+
+:::warning    
+Don’t use it if you have just started using ClickHouse.
+:::
+
+Configuration template:
+
+``` xml
+<compression>
+    <case>
+      <min_part_size>...</min_part_size>
+      <min_part_size_ratio>...</min_part_size_ratio>
+      <method>...</method>
+      <level>...</level>
+    </case>
+    ...
+</compression>
+```
+
+`<case>` fields:
+
+-   `min_part_size` – The minimum size of a data part.
+-   `min_part_size_ratio` – The ratio of the data part size to the table size.
+-   `method` – Compression method. Acceptable values: `lz4`, `lz4hc`, `zstd`.
+-   `level` – Compression level. See [Codecs](../../sql-reference/statements/create/table.md#create-query-general-purpose-codecs).
+
+You can configure multiple `<case>` sections.
+
+Actions when conditions are met:
+
+-   If a data part matches a condition set, ClickHouse uses the specified compression method.
+-   If a data part matches multiple condition sets, ClickHouse uses the first matched condition set.
+
+If no conditions met for a data part, ClickHouse uses the `lz4` compression.
+
+**Example**
+
+``` xml
+<compression incl="clickhouse_compression">
+    <case>
+        <min_part_size>10000000000</min_part_size>
+        <min_part_size_ratio>0.01</min_part_size_ratio>
+        <method>zstd</method>
+        <level>1</level>
+    </case>
+</compression>
+```
+
+## encryption {#server-settings-encryption}
+
+Configures a command to obtain a key to be used by [encryption codecs](../../sql-reference/statements/create/table.md#create-query-encryption-codecs). Key (or keys) should be written in environment variables or set in the configuration file.
+
+Keys can be hex or string with a length equal to 16 bytes.
+
+**Example**
+
+Loading from config:
+
+```xml
+<encryption_codecs>
+    <aes_128_gcm_siv>
+        <key>1234567812345678</key>
+    </aes_128_gcm_siv>
+</encryption_codecs>
+```
+
+:::note
+Storing keys in the configuration file is not recommended. It isn't secure. You can move the keys into a separate config file on a secure disk and put a symlink to that config file to `config.d/` folder.
+:::
+
+Loading from config, when the key is in hex:
+
+```xml
+<encryption_codecs>
+    <aes_128_gcm_siv>
+        <key_hex>00112233445566778899aabbccddeeff</key_hex>
+    </aes_128_gcm_siv>
+</encryption_codecs>
+```
+
+Loading key from the environment variable:
+
+```xml
+<encryption_codecs>
+    <aes_128_gcm_siv>
+        <key_hex from_env="ENVVAR"></key_hex>
+    </aes_128_gcm_siv>
+</encryption_codecs>
+```
+
+Here `current_key_id` sets the current key for encryption, and all specified keys can be used for decryption.
+
+Each of these methods can be applied for multiple keys:
+
+```xml
+<encryption_codecs>
+    <aes_128_gcm_siv>
+        <key_hex id="0">00112233445566778899aabbccddeeff</key_hex>
+        <key_hex id="1" from_env="ENVVAR"></key_hex>
+        <current_key_id>1</current_key_id>
+    </aes_128_gcm_siv>
+</encryption_codecs>
+```
+
+Here `current_key_id` shows current key for encryption.
+
+Also, users can add nonce that must be 12 bytes long (by default encryption and decryption processes use nonce that consists of zero bytes):
+
+```xml
+<encryption_codecs>
+    <aes_128_gcm_siv>
+        <nonce>012345678910</nonce>
+    </aes_128_gcm_siv>
+</encryption_codecs>
+```
+
+Or it can be set in hex:
+
+```xml
+<encryption_codecs>
+    <aes_128_gcm_siv>
+        <nonce_hex>abcdefabcdef</nonce_hex>
+    </aes_128_gcm_siv>
+</encryption_codecs>
+```
+
+Everything mentioned above can be applied for `aes_256_gcm_siv` (but the key must be 32 bytes long).
+
+
+## custom_settings_prefixes {#custom_settings_prefixes}
+
+List of prefixes for [custom settings](../../operations/settings/index.md#custom_settings). The prefixes must be separated with commas.
+
+**Example**
+
+```xml
+<custom_settings_prefixes>custom_</custom_settings_prefixes>
+```
+
+**See Also**
+
+-   [Custom settings](../../operations/settings/index.md#custom_settings)
+
+## core_dump {#server_configuration_parameters-core_dump}
+
+Configures soft limit for core dump file size.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `1073741824` (1 GB).
+
+:::note
+Hard limit is configured via system tools
+:::
+
+**Example**
+
+```xml
+<core_dump>
+    <size_limit>1073741824</size_limit>
+</core_dump>
+```
+
+## database_atomic_delay_before_drop_table_sec {#database_atomic_delay_before_drop_table_sec}
+
+Sets the delay before remove table data in seconds. If the query has `SYNC` modifier, this setting is ignored.
+
+Default value: `480` (8 minute).
+
+## default_database {#default-database}
+
+The default database.
+
+To get a list of databases, use the [SHOW DATABASES](../../sql-reference/statements/show.md#show-databases) query.
+
+**Example**
+
+``` xml
+<default_database>default</default_database>
+```
+
+## default_profile {#default-profile}
+
+Default settings profile.
+
+Settings profiles are located in the file specified in the parameter `user_config`.
+
+**Example**
+
+``` xml
+<default_profile>default</default_profile>
+```
+
+## default_replica_path {#default_replica_path}
+
+The path to the table in ZooKeeper.
+
+**Example**
+
+``` xml
+<default_replica_path>/clickhouse/tables/{uuid}/{shard}</default_replica_path>
+```
+## default_replica_name {#default_replica_name}
+
+ The replica name in ZooKeeper.
+
+**Example**
+
+``` xml
+<default_replica_name>{replica}</default_replica_name>
+```
+
+## dictionaries_config {#server_configuration_parameters-dictionaries_config}
+
+The path to the config file for external dictionaries.
+
+Path:
+
+-   Specify the absolute path or the path relative to the server config file.
+-   The path can contain wildcards \* and ?.
+
+See also “[External dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md)”.
+
+**Example**
+
+``` xml
+<dictionaries_config>*_dictionary.xml</dictionaries_config>
+```
+
+## dictionaries_lazy_load {#server_configuration_parameters-dictionaries_lazy_load}
+
+Lazy loading of dictionaries.
+
+If `true`, then each dictionary is created on first use. If dictionary creation failed, the function that was using the dictionary throws an exception.
+
+If `false`, all dictionaries are created when the server starts, if the dictionary or dictionaries are created too long or are created with errors, then the server boots without of these dictionaries and continues to try to create these dictionaries.
+
+The default is `true`.
+
+**Example**
+
+``` xml
+<dictionaries_lazy_load>true</dictionaries_lazy_load>
+```
+
+## format_schema_path {#server_configuration_parameters-format_schema_path}
+
+The path to the directory with the schemes for the input data, such as schemas for the [CapnProto](../../interfaces/formats.md#capnproto) format.
+
+**Example**
+
+``` xml
+  <!-- Directory containing schema files for various input formats. -->
+  <format_schema_path>format_schemas/</format_schema_path>
+```
+
+## graphite {#server_configuration_parameters-graphite}
+
+Sending data to [Graphite](https://github.com/graphite-project).
+
+Settings:
+
+-   host – The Graphite server.
+-   port – The port on the Graphite server.
+-   interval – The interval for sending, in seconds.
+-   timeout – The timeout for sending data, in seconds.
+-   root_path – Prefix for keys.
+-   metrics – Sending data from the [system.metrics](../../operations/system-tables/metrics.md#system_tables-metrics) table.
+-   events – Sending deltas data accumulated for the time period from the [system.events](../../operations/system-tables/events.md#system_tables-events) table.
+-   events_cumulative – Sending cumulative data from the [system.events](../../operations/system-tables/events.md#system_tables-events) table.
+-   asynchronous_metrics – Sending data from the [system.asynchronous_metrics](../../operations/system-tables/asynchronous_metrics.md#system_tables-asynchronous_metrics) table.
+
+You can configure multiple `<graphite>` clauses. For instance, you can use this for sending different data at different intervals.
+
+**Example**
+
+``` xml
+<graphite>
+    <host>localhost</host>
+    <port>42000</port>
+    <timeout>0.1</timeout>
+    <interval>60</interval>
+    <root_path>one_min</root_path>
+    <metrics>true</metrics>
+    <events>true</events>
+    <events_cumulative>false</events_cumulative>
+    <asynchronous_metrics>true</asynchronous_metrics>
+</graphite>
+```
+
+## graphite_rollup {#server_configuration_parameters-graphite-rollup}
+
+Settings for thinning data for Graphite.
+
+For more details, see [GraphiteMergeTree](../../engines/table-engines/mergetree-family/graphitemergetree.md).
+
+**Example**
+
+``` xml
+<graphite_rollup_example>
+    <default>
+        <function>max</function>
+        <retention>
+            <age>0</age>
+            <precision>60</precision>
+        </retention>
+        <retention>
+            <age>3600</age>
+            <precision>300</precision>
+        </retention>
+        <retention>
+            <age>86400</age>
+            <precision>3600</precision>
+        </retention>
+    </default>
+</graphite_rollup_example>
+```
+
+## http_port/https_port {#http-porthttps-port}
+
+The port for connecting to the server over HTTP(s).
+
+If `https_port` is specified, [openSSL](#server_configuration_parameters-openssl) must be configured.
+
+If `http_port` is specified, the OpenSSL configuration is ignored even if it is set.
+
+**Example**
+
+``` xml
+<https_port>9999</https_port>
+```
+
+## http_server_default_response {#server_configuration_parameters-http_server_default_response}
+
+The page that is shown by default when you access the ClickHouse HTTP(s) server.
+The default value is “Ok.” (with a line feed at the end)
+
+**Example**
+
+Opens `https://tabix.io/` when accessing `http://localhost: http_port`.
+
+``` xml
+<http_server_default_response>
+  <![CDATA[<html ng-app="SMI2"><head><base href="http://ui.tabix.io/"></head><body><div ui-view="" class="content-ui"></div><script src="http://loader.tabix.io/master.js"></script></body></html>]]>
+</http_server_default_response>
+```  
+## hsts_max_age  {#hsts-max-age}
+  
+Expired time for HSTS in seconds. The default value is 0 means clickhouse disabled HSTS. If you set a positive number, the HSTS will be enabled and the max-age is the number you set.  
+  
+**Example**  
+
+```xml
+<hsts_max_age>600000</hsts_max_age>
+```
+
+## include_from {#server_configuration_parameters-include_from}
+
+The path to the file with substitutions.
+
+For more information, see the section “[Configuration files](../../operations/configuration-files.md#configuration_files)”.
+
+**Example**
+
+``` xml
+<include_from>/etc/metrica.xml</include_from>
+```
+
+## interserver_http_port {#interserver-http-port}
+
+Port for exchanging data between ClickHouse servers.
+
+**Example**
+
+``` xml
+<interserver_http_port>9009</interserver_http_port>
+```
+
+## interserver_http_host {#interserver-http-host}
+
+The hostname that can be used by other servers to access this server.
+
+If omitted, it is defined in the same way as the `hostname-f` command.
+
+Useful for breaking away from a specific network interface.
+
+**Example**
+
+``` xml
+<interserver_http_host>example.clickhouse.com</interserver_http_host>
+```
+
+## interserver_https_port {#interserver-https-port}
+
+Port for exchanging data between ClickHouse servers over `HTTPS`.
+
+**Example**
+
+``` xml
+<interserver_https_port>9010</interserver_https_port>
+```
+
+## interserver_https_host {#interserver-https-host}
+
+Similar to `interserver_http_host`, except that this hostname can be used by other servers to access this server over `HTTPS`.
+
+**Example**
+
+``` xml
+<interserver_https_host>example.clickhouse.com</interserver_https_host>
+```
+
+## interserver_http_credentials {#server-settings-interserver-http-credentials}
+
+A username and a password used to connect to other servers during [replication](../../engines/table-engines/mergetree-family/replication.md). Also the server authenticates other replicas using these credentials. So, `interserver_http_credentials` must be the same for all replicas in a cluster.
+
+By default, if `interserver_http_credentials` section is omitted, authentication is not used during replication.
+
+:::note
+`interserver_http_credentials` settings do not relate to a ClickHouse client credentials [configuration](../../interfaces/cli.md#configuration_files).
+:::
+
+:::note
+These credentials are common for replication via `HTTP` and `HTTPS`.
+:::
+
+The section contains the following parameters:
+
+-   `user` — Username.
+-   `password` — Password.
+-   `allow_empty` — If `true`, then other replicas are allowed to connect without authentication even if credentials are set. If `false`, then connections without authentication are refused. Default value: `false`.
+-   `old` — Contains old `user` and `password` used during credential rotation. Several `old` sections can be specified.
+
+**Credentials Rotation**
+
+ClickHouse supports dynamic interserver credentials rotation without stopping all replicas at the same time to update their configuration. Credentials can be changed in several steps.
+
+To enable authentication, set `interserver_http_credentials.allow_empty` to `true` and add credentials. This allows connections with authentication and without it.
+
+``` xml
+<interserver_http_credentials>
+    <user>admin</user>
+    <password>111</password>
+    <allow_empty>true</allow_empty>
+</interserver_http_credentials>
+```
+
+After configuring all replicas set `allow_empty` to `false` or remove this setting. It makes authentication with new credentials mandatory.
+
+To change existing credentials, move the username and the password to `interserver_http_credentials.old` section and update `user` and `password` with new values. At this point the server uses new credentials to connect to other replicas and accepts connections with either new or old credentials. 
+
+``` xml
+<interserver_http_credentials>
+    <user>admin</user>
+    <password>222</password>
+    <old>
+        <user>admin</user>
+        <password>111</password>
+    </old>
+    <old>
+        <user>temp</user>
+        <password>000</password>
+    </old>
+</interserver_http_credentials>
+```
+
+When new credentials are applied to all replicas, old credentials may be removed.
+
+## keep_alive_timeout {#keep-alive-timeout}
+
+The number of seconds that ClickHouse waits for incoming requests before closing the connection. Defaults to 10 seconds.
+
+**Example**
+
+``` xml
+<keep_alive_timeout>10</keep_alive_timeout>
+```
+
+## listen_host {#server_configuration_parameters-listen_host}
+
+Restriction on hosts that requests can come from. If you want the server to answer all of them, specify `::`.
+
+Examples:
+
+``` xml
+<listen_host>::1</listen_host>
+<listen_host>127.0.0.1</listen_host>
+```
+
+## listen_backlog {#server_configuration_parameters-listen_backlog}
+
+Backlog (queue size of pending connections) of the listen socket.
+
+Default value: `4096` (as in linux [5.4+](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=19f92a030ca6d772ab44b22ee6a01378a8cb32d4)).
+
+Usually this value does not need to be changed, since:
+-  default value is large enough,
+-  and for accepting client's connections server has separate thread.
+
+So even if you have `TcpExtListenOverflows` (from `nstat`) non zero and this counter grows for ClickHouse server it does not mean that this value need to be increased, since:
+-  usually if 4096 is not enough it shows some internal ClickHouse scaling issue, so it is better to report an issue.
+-  and it does not mean that the server can handle more connections later (and even if it could, by that moment clients may be gone or disconnected).
+
+Examples:
+
+``` xml
+<listen_backlog>4096</listen_backlog>
+```
+
+## logger {#server_configuration_parameters-logger}
+
+Logging settings.
+
+Keys:
+
+-   `level` – Logging level. Acceptable values: `trace`, `debug`, `information`, `warning`, `error`.
+-   `log` – The log file. Contains all the entries according to `level`.
+-   `errorlog` – Error log file.
+-   `size` – Size of the file. Applies to `log` and `errorlog`. Once the file reaches `size`, ClickHouse archives and renames it, and creates a new log file in its place.
+-   `count` – The number of archived log files that ClickHouse stores.
+
+**Example**
+
+``` xml
+<logger>
+    <level>trace</level>
+    <log>/var/log/clickhouse-server/clickhouse-server.log</log>
+    <errorlog>/var/log/clickhouse-server/clickhouse-server.err.log</errorlog>
+    <size>1000M</size>
+    <count>10</count>
+</logger>
+```
+
+Writing to the syslog is also supported. Config example:
+
+``` xml
+<logger>
+    <use_syslog>1</use_syslog>
+    <syslog>
+        <address>syslog.remote:10514</address>
+        <hostname>myhost.local</hostname>
+        <facility>LOG_LOCAL6</facility>
+        <format>syslog</format>
+    </syslog>
+</logger>
+```
+
+Keys for syslog:
+
+-   use_syslog — Required setting if you want to write to the syslog.
+-   address — The host\[:port\] of syslogd. If omitted, the local daemon is used.
+-   hostname — Optional. The name of the host that logs are sent from.
+-   facility — [The syslog facility keyword](https://en.wikipedia.org/wiki/Syslog#Facility) in uppercase letters with the “LOG_” prefix: (`LOG_USER`, `LOG_DAEMON`, `LOG_LOCAL3`, and so on).
+    Default value: `LOG_USER` if `address` is specified, `LOG_DAEMON` otherwise.
+-   format – Message format. Possible values: `bsd` and `syslog.`
+
+## send_crash_reports {#server_configuration_parameters-send_crash_reports}
+
+Settings for opt-in sending crash reports to the ClickHouse core developers team via [Sentry](https://sentry.io).
+Enabling it, especially in pre-production environments, is highly appreciated.
+
+The server will need access to the public Internet via IPv4 (at the time of writing IPv6 is not supported by Sentry) for this feature to be functioning properly.
+
+Keys:
+
+-   `enabled` – Boolean flag to enable the feature, `false` by default. Set to `true` to allow sending crash reports.
+-   `endpoint` – You can override the Sentry endpoint URL for sending crash reports. It can be either a separate Sentry account or your self-hosted Sentry instance. Use the [Sentry DSN](https://docs.sentry.io/error-reporting/quickstart/?platform=native#configure-the-sdk) syntax.
+-   `anonymize` - Avoid attaching the server hostname to the crash report.
+-   `http_proxy` - Configure HTTP proxy for sending crash reports.
+-   `debug` - Sets the Sentry client into debug mode.
+-   `tmp_path` - Filesystem path for temporary crash report state.
+
+**Recommended way to use**
+
+``` xml
+<send_crash_reports>
+    <enabled>true</enabled>
+</send_crash_reports>
+```
+
+## macros {#macros}
+
+Parameter substitutions for replicated tables.
+
+Can be omitted if replicated tables are not used.
+
+For more information, see the section [Creating replicated tables](../../engines/table-engines/mergetree-family/replication.md#creating-replicated-tables).
+
+**Example**
+
+``` xml
+<macros incl="macros" optional="true" />
+```
+
+## mark_cache_size {#server-mark-cache-size}
+
+Approximate size (in bytes) of the cache of marks used by table engines of the [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) family.
+
+The cache is shared for the server and memory is allocated as needed.
+
+**Example**
+
+``` xml
+<mark_cache_size>5368709120</mark_cache_size>
+```
+
+## max_server_memory_usage {#max_server_memory_usage}
+
+Limits total RAM usage by the ClickHouse server.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Auto.
+
+Default value: `0`.
+
+**Additional Info**
+
+The default `max_server_memory_usage` value is calculated as `memory_amount * max_server_memory_usage_to_ram_ratio`.
+
+**See also**
+
+-   [max_memory_usage](../../operations/settings/query-complexity.md#settings_max_memory_usage)
+-   [max_server_memory_usage_to_ram_ratio](#max_server_memory_usage_to_ram_ratio)
+
+## max_server_memory_usage_to_ram_ratio {#max_server_memory_usage_to_ram_ratio}
+
+Defines the fraction of total physical RAM amount, available to the ClickHouse server. If the server tries to utilize more, the memory is cut down to the appropriate amount.
+
+Possible values:
+
+-   Positive double.
+-   0 — The ClickHouse server can use all available RAM.
+
+Default value: `0.9`.
+
+**Usage**
+
+On hosts with low RAM and swap, you possibly need setting `max_server_memory_usage_to_ram_ratio` larger than 1.
+
+**Example**
+
+``` xml
+<max_server_memory_usage_to_ram_ratio>0.9</max_server_memory_usage_to_ram_ratio>
+```
+
+**See Also**
+
+-   [max_server_memory_usage](#max_server_memory_usage)
+
+## max_concurrent_queries {#max-concurrent-queries}
+
+The maximum number of simultaneously processed queries related to MergeTree table.
+Queries may be limited by other settings: [max_concurrent_insert_queries](#max-concurrent-insert-queries), [max_concurrent_select_queries](#max-concurrent-select-queries), [max_concurrent_queries_for_user](#max-concurrent-queries-for-user), [max_concurrent_queries_for_all_users](#max-concurrent-queries-for-all-users), [min_marks_to_honor_max_concurrent_queries](#min-marks-to-honor-max-concurrent-queries).
+
+:::note
+These settings can be modified at runtime and will take effect immediately. Queries that are already running will remain unchanged.
+:::
+
+Possible values:
+
+-   Positive integer.
+-   0 — No limit.
+
+Default value: `100`.
+
+**Example**
+
+``` xml
+<max_concurrent_queries>100</max_concurrent_queries>
+```
+
+## max_concurrent_insert_queries {#max-concurrent-insert-queries}
+
+The maximum number of simultaneously processed `INSERT` queries.
+
+:::note
+These settings can be modified at runtime and will take effect immediately. Queries that are already running will remain unchanged.
+:::
+
+Possible values:
+
+-   Positive integer.
+-   0 — No limit.
+
+Default value: `0`.
+
+**Example**
+
+``` xml
+<max_concurrent_insert_queries>100</max_concurrent_insert_queries>
+```
+
+## max_concurrent_select_queries {#max-concurrent-select-queries}
+
+The maximum number of simultaneously processed `SELECT` queries.
+
+:::note
+These settings can be modified at runtime and will take effect immediately. Queries that are already running will remain unchanged.
+:::
+
+Possible values:
+
+-   Positive integer.
+-   0 — No limit.
+
+Default value: `0`.
+
+**Example**
+
+``` xml
+<max_concurrent_select_queries>100</max_concurrent_select_queries>
+```
+
+## max_concurrent_queries_for_user {#max-concurrent-queries-for-user}
+
+The maximum number of simultaneously processed queries related to MergeTree table per user.
+
+Possible values:
+
+-   Positive integer.
+-   0 — No limit.
+
+Default value: `0`.
+
+**Example**
+
+``` xml
+<max_concurrent_queries_for_user>5</max_concurrent_queries_for_user>
+```
+
+## max_concurrent_queries_for_all_users {#max-concurrent-queries-for-all-users}
+
+Throw exception if the value of this setting is less or equal than the current number of simultaneously processed queries.
+
+Example: `max_concurrent_queries_for_all_users` can be set to 99 for all users and database administrator can set it to 100 for itself to run queries for investigation even when the server is overloaded.
+
+Modifying the setting for one query or user does not affect other queries.
+
+Possible values:
+
+-   Positive integer.
+-   0 — No limit.
+
+Default value: `0`.
+
+**Example**
+
+``` xml
+<max_concurrent_queries_for_all_users>99</max_concurrent_queries_for_all_users>
+```
+
+**See Also**
+
+-   [max_concurrent_queries](#max-concurrent-queries)
+
+## min_marks_to_honor_max_concurrent_queries {#min-marks-to-honor-max-concurrent-queries}
+
+The minimal number of marks read by the query for applying the [max_concurrent_queries](#max-concurrent-queries) setting.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Disabled.
+
+**Example**
+
+``` xml
+<min_marks_to_honor_max_concurrent_queries>10</min_marks_to_honor_max_concurrent_queries>
+```
+
+## max_connections {#max-connections}
+
+The maximum number of inbound connections.
+
+**Example**
+
+``` xml
+<max_connections>4096</max_connections>
+```
+
+## max_open_files {#max-open-files}
+
+The maximum number of open files.
+
+By default: `maximum`.
+
+We recommend using this option in Mac OS X since the `getrlimit()` function returns an incorrect value.
+
+**Example**
+
+``` xml
+<max_open_files>262144</max_open_files>
+```
+
+## max_table_size_to_drop {#max-table-size-to-drop}
+
+Restriction on deleting tables.
+
+If the size of a [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) table exceeds `max_table_size_to_drop` (in bytes), you can’t delete it using a DROP query.
+
+If you still need to delete the table without restarting the ClickHouse server, create the `<clickhouse-path>/flags/force_drop_table` file and run the DROP query.
+
+Default value: 50 GB.
+
+The value 0 means that you can delete all tables without any restrictions.
+
+**Example**
+
+``` xml
+<max_table_size_to_drop>0</max_table_size_to_drop>
+```
+
+## max_thread_pool_size {#max-thread-pool-size}
+
+ClickHouse uses threads from the Global Thread pool to process queries. If there is no idle thread to process a query, then a new thread is created in the pool. `max_thread_pool_size` limits the maximum number of threads in the pool.
+
+Possible values: 
+
+-   Positive integer.
+
+Default value: `10000`.
+
+**Example**
+
+``` xml
+<max_thread_pool_size>12000</max_thread_pool_size>
+```
+
+## max_thread_pool_free_size {#max-thread-pool-free-size}
+
+If the number of **idle** threads in the Global Thread pool is greater than `max_thread_pool_free_size`, then ClickHouse releases resources occupied by some threads and the pool size is decreased. Threads can be created again if necessary.
+
+Possible values: 
+
+-   Positive integer.
+
+Default value: `1000`.
+
+**Example**
+
+``` xml
+<max_thread_pool_free_size>1200</max_thread_pool_free_size>
+```
+
+## thread_pool_queue_size {#thread-pool-queue-size}
+
+The maximum number of jobs that can be scheduled on the Global Thread pool. Increasing queue size leads to larger memory usage. It is recommended to keep this value equal to [max_thread_pool_size](#max-thread-pool-size).
+
+Possible values: 
+
+-   Positive integer.
+
+Default value: `10000`.
+
+**Example**
+
+``` xml
+<thread_pool_queue_size>12000</thread_pool_queue_size>
+```
+
+## merge_tree {#server_configuration_parameters-merge_tree}
+
+Fine tuning for tables in the [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md).
+
+For more information, see the MergeTreeSettings.h header file.
+
+**Example**
+
+``` xml
+<merge_tree>
+    <max_suspicious_broken_parts>5</max_suspicious_broken_parts>
+</merge_tree>
+```
+
+## metric_log {#metric_log}
+
+It is enabled by default. If it`s not, you can do this manually.
+
+**Enabling**
+
+To manually turn on metrics history collection [`system.metric_log`](../../operations/system-tables/metric_log.md), create `/etc/clickhouse-server/config.d/metric_log.xml` with the following content:
+
+``` xml
+<clickhouse>
+    <metric_log>
+        <database>system</database>
+        <table>metric_log</table>
+        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+        <collect_interval_milliseconds>1000</collect_interval_milliseconds>
+    </metric_log>
+</clickhouse>
+```
+
+**Disabling**
+
+To disable `metric_log` setting, you should create the following file `/etc/clickhouse-server/config.d/disable_metric_log.xml` with the following content:
+
+``` xml
+<clickhouse>
+<metric_log remove="1" />
+</clickhouse>
+```
+
+## replicated_merge_tree {#server_configuration_parameters-replicated_merge_tree}
+
+Fine tuning for tables in the [ReplicatedMergeTree](../../engines/table-engines/mergetree-family/mergetree.md).
+
+This setting has a higher priority.
+
+For more information, see the MergeTreeSettings.h header file.
+
+**Example**
+
+``` xml
+<replicated_merge_tree>
+    <max_suspicious_broken_parts>5</max_suspicious_broken_parts>
+</replicated_merge_tree>
+```
+
+## openSSL {#server_configuration_parameters-openssl}
+
+SSL client/server configuration.
+
+Support for SSL is provided by the `libpoco` library. The interface is described in the file [SSLManager.h](https://github.com/ClickHouse-Extras/poco/blob/master/NetSSL_OpenSSL/include/Poco/Net/SSLManager.h)
+
+Keys for server/client settings:
+
+-   privateKeyFile – The path to the file with the secret key of the PEM certificate. The file may contain a key and certificate at the same time.
+-   certificateFile – The path to the client/server certificate file in PEM format. You can omit it if `privateKeyFile` contains the certificate.
+-   caConfig – The path to the file or directory that contains trusted root certificates.
+-   verificationMode – The method for checking the node’s certificates. Details are in the description of the [Context](https://github.com/ClickHouse-Extras/poco/blob/master/NetSSL_OpenSSL/include/Poco/Net/Context.h) class. Possible values: `none`, `relaxed`, `strict`, `once`.
+-   verificationDepth – The maximum length of the verification chain. Verification will fail if the certificate chain length exceeds the set value.
+-   loadDefaultCAFile – Indicates that built-in CA certificates for OpenSSL will be used. Acceptable values: `true`, `false`. \|
+-   cipherList – Supported OpenSSL encryptions. For example: `ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH`.
+-   cacheSessions – Enables or disables caching sessions. Must be used in combination with `sessionIdContext`. Acceptable values: `true`, `false`.
+-   sessionIdContext – A unique set of random characters that the server appends to each generated identifier. The length of the string must not exceed `SSL_MAX_SSL_SESSION_ID_LENGTH`. This parameter is always recommended since it helps avoid problems both if the server caches the session and if the client requested caching. Default value: `${application.name}`.
+-   sessionCacheSize – The maximum number of sessions that the server caches. Default value: 1024\*20. 0 – Unlimited sessions.
+-   sessionTimeout – Time for caching the session on the server.
+-   extendedVerification – Automatically extended verification of certificates after the session ends. Acceptable values: `true`, `false`.
+-   requireTLSv1 – Require a TLSv1 connection. Acceptable values: `true`, `false`.
+-   requireTLSv1_1 – Require a TLSv1.1 connection. Acceptable values: `true`, `false`.
+-   requireTLSv1_2 – Require a TLSv1.2 connection. Acceptable values: `true`, `false`.
+-   fips – Activates OpenSSL FIPS mode. Supported if the library’s OpenSSL version supports FIPS.
+-   privateKeyPassphraseHandler – Class (PrivateKeyPassphraseHandler subclass) that requests the passphrase for accessing the private key. For example: `<privateKeyPassphraseHandler>`, `<name>KeyFileHandler</name>`, `<options><password>test</password></options>`, `</privateKeyPassphraseHandler>`.
+-   invalidCertificateHandler – Class (a subclass of CertificateHandler) for verifying invalid certificates. For example: `<invalidCertificateHandler> <name>ConsoleCertificateHandler</name> </invalidCertificateHandler>` .
+-   disableProtocols – Protocols that are not allowed to use.
+-   preferServerCiphers – Preferred server ciphers on the client.
+
+**Example of settings:**
+
+``` xml
+<openSSL>
+    <server>
+        <!-- openssl req -subj "/CN=localhost" -new -newkey rsa:2048 -days 365 -nodes -x509 -keyout /etc/clickhouse-server/server.key -out /etc/clickhouse-server/server.crt -->
+        <certificateFile>/etc/clickhouse-server/server.crt</certificateFile>
+        <privateKeyFile>/etc/clickhouse-server/server.key</privateKeyFile>
+        <!-- openssl dhparam -out /etc/clickhouse-server/dhparam.pem 4096 -->
+        <dhParamsFile>/etc/clickhouse-server/dhparam.pem</dhParamsFile>
+        <verificationMode>none</verificationMode>
+        <loadDefaultCAFile>true</loadDefaultCAFile>
+        <cacheSessions>true</cacheSessions>
+        <disableProtocols>sslv2,sslv3</disableProtocols>
+        <preferServerCiphers>true</preferServerCiphers>
+    </server>
+    <client>
+        <loadDefaultCAFile>true</loadDefaultCAFile>
+        <cacheSessions>true</cacheSessions>
+        <disableProtocols>sslv2,sslv3</disableProtocols>
+        <preferServerCiphers>true</preferServerCiphers>
+        <!-- Use for self-signed: <verificationMode>none</verificationMode> -->
+        <invalidCertificateHandler>
+            <!-- Use for self-signed: <name>AcceptCertificateHandler</name> -->
+            <name>RejectCertificateHandler</name>
+        </invalidCertificateHandler>
+    </client>
+</openSSL>
+```
+
+## part_log {#server_configuration_parameters-part-log}
+
+Logging events that are associated with [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md). For instance, adding or merging data. You can use the log to simulate merge algorithms and compare their characteristics. You can visualize the merge process.
+
+Queries are logged in the [system.part_log](../../operations/system-tables/part_log.md#system_tables-part-log) table, not in a separate file. You can configure the name of this table in the `table` parameter (see below).
+
+Use the following parameters to configure logging:
+
+-   `database` – Name of the database.
+-   `table` – Name of the system table.
+-   `partition_by` — [Custom partitioning key](../../engines/table-engines/mergetree-family/custom-partitioning-key.md) for a system table. Can't be used if `engine` defined.
+-   `engine` - [MergeTree Engine Definition](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table) for a system table. Can't be used if `partition_by` defined.
+-   `flush_interval_milliseconds` – Interval for flushing data from the buffer in memory to the table.
+
+**Example**
+
+``` xml
+<part_log>
+    <database>system</database>
+    <table>part_log</table>
+    <partition_by>toMonday(event_date)</partition_by>
+    <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+</part_log>
+```
+
+## path {#server_configuration_parameters-path}
+
+The path to the directory containing data.
+
+:::note
+The trailing slash is mandatory.
+:::
+
+**Example**
+
+``` xml
+<path>/var/lib/clickhouse/</path>
+```
+
+## prometheus {#server_configuration_parameters-prometheus}
+
+Exposing metrics data for scraping from [Prometheus](https://prometheus.io).
+
+Settings:
+
+-   `endpoint` – HTTP endpoint for scraping metrics by prometheus server. Start from ‘/’.
+-   `port` – Port for `endpoint`.
+-   `metrics` – Flag that sets to expose metrics from the [system.metrics](../../operations/system-tables/metrics.md#system_tables-metrics) table.
+-   `events` – Flag that sets to expose metrics from the [system.events](../../operations/system-tables/events.md#system_tables-events) table.
+-   `asynchronous_metrics` – Flag that sets to expose current metrics values from the [system.asynchronous_metrics](../../operations/system-tables/asynchronous_metrics.md#system_tables-asynchronous_metrics) table.
+
+**Example**
+
+``` xml
+ <prometheus>
+        <endpoint>/metrics</endpoint>
+        <port>8001</port>
+        <metrics>true</metrics>
+        <events>true</events>
+        <asynchronous_metrics>true</asynchronous_metrics>
+    </prometheus>
+```
+
+## query_log {#server_configuration_parameters-query-log}
+
+Setting for logging queries received with the [log_queries=1](../../operations/settings/settings.md) setting.
+
+Queries are logged in the [system.query_log](../../operations/system-tables/query_log.md#system_tables-query_log) table, not in a separate file. You can change the name of the table in the `table` parameter (see below).
+
+Use the following parameters to configure logging:
+
+-   `database` – Name of the database.
+-   `table` – Name of the system table the queries will be logged in.
+-   `partition_by` — [Custom partitioning key](../../engines/table-engines/mergetree-family/custom-partitioning-key.md) for a system table. Can't be used if `engine` defined.
+-   `engine` - [MergeTree Engine Definition](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table) for a system table. Can't be used if `partition_by` defined.
+-   `flush_interval_milliseconds` – Interval for flushing data from the buffer in memory to the table.
+
+If the table does not exist, ClickHouse will create it. If the structure of the query log changed when the ClickHouse server was updated, the table with the old structure is renamed, and a new table is created automatically.
+
+**Example**
+
+``` xml
+<query_log>
+    <database>system</database>
+    <table>query_log</table>
+    <engine>Engine = MergeTree PARTITION BY event_date ORDER BY event_time TTL event_date + INTERVAL 30 day</engine>
+    <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+</query_log>
+```
+
+## query_thread_log {#server_configuration_parameters-query_thread_log}
+
+Setting for logging threads of queries received with the [log_query_threads=1](../../operations/settings/settings.md#settings-log-query-threads) setting.
+
+Queries are logged in the [system.query_thread_log](../../operations/system-tables/query_thread_log.md#system_tables-query_thread_log) table, not in a separate file. You can change the name of the table in the `table` parameter (see below).
+
+Use the following parameters to configure logging:
+
+-   `database` – Name of the database.
+-   `table` – Name of the system table the queries will be logged in.
+-   `partition_by` — [Custom partitioning key](../../engines/table-engines/mergetree-family/custom-partitioning-key.md) for a system table. Can't be used if `engine` defined.
+-   `engine` - [MergeTree Engine Definition](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table) for a system table. Can't be used if `partition_by` defined.
+-   `flush_interval_milliseconds` – Interval for flushing data from the buffer in memory to the table.
+
+If the table does not exist, ClickHouse will create it. If the structure of the query thread log changed when the ClickHouse server was updated, the table with the old structure is renamed, and a new table is created automatically.
+
+**Example**
+
+``` xml
+<query_thread_log>
+    <database>system</database>
+    <table>query_thread_log</table>
+    <partition_by>toMonday(event_date)</partition_by>
+    <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+</query_thread_log>
+```
+
+## query_views_log {#server_configuration_parameters-query_views_log}
+
+Setting for logging views (live, materialized etc) dependant of queries received with the [log_query_views=1](../../operations/settings/settings.md#settings-log-query-views) setting.
+
+Queries are logged in the [system.query_views_log](../../operations/system-tables/query_views_log.md#system_tables-query_views_log) table, not in a separate file. You can change the name of the table in the `table` parameter (see below).
+
+Use the following parameters to configure logging:
+
+-   `database` – Name of the database.
+-   `table` – Name of the system table the queries will be logged in.
+-   `partition_by` — [Custom partitioning key](../../engines/table-engines/mergetree-family/custom-partitioning-key.md) for a system table. Can't be used if `engine` defined.
+-   `engine` - [MergeTree Engine Definition](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table) for a system table. Can't be used if `partition_by` defined.
+-   `flush_interval_milliseconds` – Interval for flushing data from the buffer in memory to the table.
+
+If the table does not exist, ClickHouse will create it. If the structure of the query views log changed when the ClickHouse server was updated, the table with the old structure is renamed, and a new table is created automatically.
+
+**Example**
+
+``` xml
+<query_views_log>
+    <database>system</database>
+    <table>query_views_log</table>
+    <partition_by>toYYYYMM(event_date)</partition_by>
+    <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+</query_views_log>
+```
+
+## text_log {#server_configuration_parameters-text_log}
+
+Settings for the [text_log](../../operations/system-tables/text_log.md#system_tables-text_log) system table for logging text messages.
+
+Parameters:
+
+-   `level` — Maximum Message Level (by default `Trace`) which will be stored in a table.
+-   `database` — Database name.
+-   `table` — Table name.
+-   `partition_by` — [Custom partitioning key](../../engines/table-engines/mergetree-family/custom-partitioning-key.md) for a system table. Can't be used if `engine` defined.
+-   `engine` - [MergeTree Engine Definition](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table) for a system table. Can't be used if `partition_by` defined.
+-   `flush_interval_milliseconds` — Interval for flushing data from the buffer in memory to the table.
+
+**Example**
+```xml
+<clickhouse>
+    <text_log>
+        <level>notice</level>
+        <database>system</database>
+        <table>text_log</table>
+        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+        <!-- <partition_by>event_date</partition_by> -->
+        <engine>Engine = MergeTree PARTITION BY event_date ORDER BY event_time TTL event_date + INTERVAL 30 day</engine>
+    </text_log>
+</clickhouse>
+```
+
+
+## trace_log {#server_configuration_parameters-trace_log}
+
+Settings for the [trace_log](../../operations/system-tables/trace_log.md#system_tables-trace_log) system table operation.
+
+Parameters:
+
+-   `database` — Database for storing a table.
+-   `table` — Table name.
+-   `partition_by` — [Custom partitioning key](../../engines/table-engines/mergetree-family/custom-partitioning-key.md) for a system table. Can't be used if `engine` defined.
+-   `engine` - [MergeTree Engine Definition](../../engines/table-engines/mergetree-family/index.md) for a system table. Can't be used if `partition_by` defined.
+-   `flush_interval_milliseconds` — Interval for flushing data from the buffer in memory to the table.
+
+The default server configuration file `config.xml` contains the following settings section:
+
+``` xml
+<trace_log>
+    <database>system</database>
+    <table>trace_log</table>
+    <partition_by>toYYYYMM(event_date)</partition_by>
+    <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+</trace_log>
+```
+
+## query_masking_rules {#query-masking-rules}
+
+Regexp-based rules, which will be applied to queries as well as all log messages before storing them in server logs,
+`system.query_log`, `system.text_log`, `system.processes` tables, and in logs sent to the client. That allows preventing
+sensitive data leakage from SQL queries (like names, emails, personal identifiers or credit card numbers) to logs.
+
+**Example**
+
+``` xml
+<query_masking_rules>
+    <rule>
+        <name>hide SSN</name>
+        <regexp>(^|\D)\d{3}-\d{2}-\d{4}($|\D)</regexp>
+        <replace>000-00-0000</replace>
+    </rule>
+</query_masking_rules>
+```
+
+Config fields:
+- `name` - name for the rule (optional)
+- `regexp` - RE2 compatible regular expression (mandatory)
+- `replace` - substitution string for sensitive data (optional, by default - six asterisks)
+
+The masking rules are applied to the whole query (to prevent leaks of sensitive data from malformed / non-parsable queries).
+
+`system.events` table have counter `QueryMaskingRulesMatch` which have an overall number of query masking rules matches.
+
+For distributed queries each server have to be configured separately, otherwise, subqueries passed to other
+nodes will be stored without masking.
+
+## remote_servers {#server-settings-remote-servers}
+
+Configuration of clusters used by the [Distributed](../../engines/table-engines/special/distributed.md) table engine and by the `cluster` table function.
+
+**Example**
+
+``` xml
+<remote_servers incl="clickhouse_remote_servers" />
+```
+
+For the value of the `incl` attribute, see the section “[Configuration files](../../operations/configuration-files.md#configuration_files)”.
+
+**See Also**
+
+-   [skip_unavailable_shards](../../operations/settings/settings.md#settings-skip_unavailable_shards)
+
+## timezone {#server_configuration_parameters-timezone}
+
+The server’s time zone.
+
+Specified as an IANA identifier for the UTC timezone or geographic location (for example, Africa/Abidjan).
+
+The time zone is necessary for conversions between String and DateTime formats when DateTime fields are output to text format (printed on the screen or in a file), and when getting DateTime from a string. Besides, the time zone is used in functions that work with the time and date if they didn’t receive the time zone in the input parameters.
+
+**Example**
+
+``` xml
+<timezone>Asia/Istanbul</timezone>
+```
+
+## tcp_port {#server_configuration_parameters-tcp_port}
+
+Port for communicating with clients over the TCP protocol.
+
+**Example**
+
+``` xml
+<tcp_port>9000</tcp_port>
+```
+
+## tcp_port_secure {#server_configuration_parameters-tcp_port_secure}
+
+TCP port for secure communication with clients. Use it with [OpenSSL](#server_configuration_parameters-openssl) settings.
+
+**Possible values**
+
+Positive integer.
+
+**Default value**
+
+``` xml
+<tcp_port_secure>9440</tcp_port_secure>
+```
+
+## mysql_port {#server_configuration_parameters-mysql_port}
+
+Port for communicating with clients over MySQL protocol.
+
+**Possible values**
+
+Positive integer.
+
+Example
+
+``` xml
+<mysql_port>9004</mysql_port>
+```
+
+## postgresql_port {#server_configuration_parameters-postgresql_port}
+
+Port for communicating with clients over PostgreSQL protocol.
+
+**Possible values**
+
+Positive integer.
+
+Example
+
+``` xml
+<postgresql_port>9005</postgresql_port>
+```
+
+## tmp_path {#tmp-path}
+
+Path to temporary data for processing large queries.
+
+:::note
+The trailing slash is mandatory.
+:::
+
+**Example**
+
+``` xml
+<tmp_path>/var/lib/clickhouse/tmp/</tmp_path>
+```
+
+## tmp_policy {#tmp-policy}
+
+Policy from [storage_configuration](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes) to store temporary files.
+
+If not set, [tmp_path](#tmp-path) is used, otherwise it is ignored.
+
+:::note
+- `move_factor` is ignored.
+- `keep_free_space_bytes` is ignored.
+- `max_data_part_size_bytes` is ignored.
+- Уou must have exactly one volume in that policy.
+:::
+
+## uncompressed_cache_size {#server-settings-uncompressed_cache_size}
+
+Cache size (in bytes) for uncompressed data used by table engines from the [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md).
+
+There is one shared cache for the server. Memory is allocated on demand. The cache is used if the option [use_uncompressed_cache](../../operations/settings/settings.md#setting-use_uncompressed_cache) is enabled.
+
+The uncompressed cache is advantageous for very short queries in individual cases.
+
+**Example**
+
+``` xml
+<uncompressed_cache_size>8589934592</uncompressed_cache_size>
+```
+
+## user_files_path {#server_configuration_parameters-user_files_path}
+
+The directory with user files. Used in the table function [file()](../../sql-reference/table-functions/file.md).
+
+**Example**
+
+``` xml
+<user_files_path>/var/lib/clickhouse/user_files/</user_files_path>
+```
+
+## users_config {#users-config}
+
+Path to the file that contains:
+
+-   User configurations.
+-   Access rights.
+-   Settings profiles.
+-   Quota settings.
+
+**Example**
+
+``` xml
+<users_config>users.xml</users_config>
+```
+
+## zookeeper {#server-settings_zookeeper}
+
+Contains settings that allow ClickHouse to interact with a [ZooKeeper](http://zookeeper.apache.org/) cluster.
+
+ClickHouse uses ZooKeeper for storing metadata of replicas when using replicated tables. If replicated tables are not used, this section of parameters can be omitted.
+
+This section contains the following parameters:
+
+-   `node` — ZooKeeper endpoint. You can set multiple endpoints.
+
+    For example:
+
+<!-- -->
+
+``` xml
+    <node index="1">
+        <host>example_host</host>
+        <port>2181</port>
+    </node>
+```
+
+      The `index` attribute specifies the node order when trying to connect to the ZooKeeper cluster.
+
+- `session_timeout_ms` — Maximum timeout for the client session in milliseconds.
+- `operation_timeout_ms` — Maximum timeout for one operation in milliseconds.
+- `root` — The [znode](http://zookeeper.apache.org/doc/r3.5.5/zookeeperOver.html#Nodes+and+ephemeral+nodes) that is used as the root for znodes used by the ClickHouse server. Optional.
+- `identity` — User and password, that can be required by ZooKeeper to give access to requested znodes. Optional.
+
+**Example configuration**
+
+``` xml
+<zookeeper>
+    <node>
+        <host>example1</host>
+        <port>2181</port>
+    </node>
+    <node>
+        <host>example2</host>
+        <port>2181</port>
+    </node>
+    <session_timeout_ms>30000</session_timeout_ms>
+    <operation_timeout_ms>10000</operation_timeout_ms>
+    <!-- Optional. Chroot suffix. Should exist. -->
+    <root>/path/to/zookeeper/node</root>
+    <!-- Optional. Zookeeper digest ACL string. -->
+    <identity>user:password</identity>
+</zookeeper>
+```
+
+**See Also**
+
+-   [Replication](../../engines/table-engines/mergetree-family/replication.md)
+-   [ZooKeeper Programmer’s Guide](http://zookeeper.apache.org/doc/current/zookeeperProgrammers.html)
+-   [Optional secured communication between ClickHouse and Zookeeper](../ssl-zookeeper.md#secured-communication-with-zookeeper)
+
+## use_minimalistic_part_header_in_zookeeper {#server-settings-use_minimalistic_part_header_in_zookeeper}
+
+Storage method for data part headers in ZooKeeper.
+
+This setting only applies to the `MergeTree` family. It can be specified:
+
+-   Globally in the [merge_tree](#server_configuration_parameters-merge_tree) section of the `config.xml` file.
+
+    ClickHouse uses the setting for all the tables on the server. You can change the setting at any time. Existing tables change their behaviour when the setting changes.
+
+-   For each table.
+
+    When creating a table, specify the corresponding [engine setting](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table). The behaviour of an existing table with this setting does not change, even if the global setting changes.
+
+**Possible values**
+
+-   0 — Functionality is turned off.
+-   1 — Functionality is turned on.
+
+If `use_minimalistic_part_header_in_zookeeper = 1`, then [replicated](../../engines/table-engines/mergetree-family/replication.md) tables store the headers of the data parts compactly using a single `znode`. If the table contains many columns, this storage method significantly reduces the volume of the data stored in Zookeeper.
+
+:::note
+After applying `use_minimalistic_part_header_in_zookeeper = 1`, you can’t downgrade the ClickHouse server to a version that does not support this setting. Be careful when upgrading ClickHouse on servers in a cluster. Don’t upgrade all the servers at once. It is safer to test new versions of ClickHouse in a test environment, or on just a few servers of a cluster.
+
+Data part headers already stored with this setting can't be restored to their previous (non-compact) representation.
+:::
+
+**Default value:** 0.
+
+## disable_internal_dns_cache {#server-settings-disable-internal-dns-cache}
+
+Disables the internal DNS cache. Recommended for operating ClickHouse in systems
+with frequently changing infrastructure such as Kubernetes.
+
+**Default value:** 0.
+
+## dns_cache_update_period {#server-settings-dns-cache-update-period}
+
+The period of updating IP addresses stored in the ClickHouse internal DNS cache (in seconds).
+The update is performed asynchronously, in a separate system thread.
+
+**Default value**: 15.
+
+**See also**
+
+-   [background_schedule_pool_size](../../operations/settings/settings.md#background_schedule_pool_size)
+
+## distributed_ddl {#server-settings-distributed_ddl}
+
+Manage executing [distributed ddl queries](../../sql-reference/distributed-ddl.md)  (CREATE, DROP, ALTER, RENAME) on cluster.
+Works only if [ZooKeeper](#server-settings_zookeeper) is enabled.
+
+**Example**
+
+```xml
+<distributed_ddl>
+    <!-- Path in ZooKeeper to queue with DDL queries -->
+    <path>/clickhouse/task_queue/ddl</path>
+
+    <!-- Settings from this profile will be used to execute DDL queries -->
+    <profile>default</profile>
+
+    <!-- Controls how much ON CLUSTER queries can be run simultaneously. -->
+    <pool_size>1</pool_size>
+
+    <!--
+         Cleanup settings (active tasks will not be removed)
+    -->
+
+    <!-- Controls task TTL (default 1 week) -->
+    <task_max_lifetime>604800</task_max_lifetime>
+
+    <!-- Controls how often cleanup should be performed (in seconds) -->
+    <cleanup_delay_period>60</cleanup_delay_period>
+
+    <!-- Controls how many tasks could be in the queue -->
+    <max_tasks_in_queue>1000</max_tasks_in_queue>
+</distributed_ddl>
+```
+
+## access_control_path {#access_control_path}
+
+Path to a folder where a ClickHouse server stores user and role configurations created by SQL commands.
+
+Default value: `/var/lib/clickhouse/access/`.
+
+**See also**
+
+- [Access Control and Account Management](../../operations/access-rights.md#access-control)
+
+## user_directories {#user_directories}
+
+Section of the configuration file that contains settings:
+-   Path to configuration file with predefined users.
+-   Path to folder where users created by SQL commands are stored.
+-   ZooKeeper node path where users created by SQL commands are stored and replicated (experimental).
+
+If this section is specified, the path from [users_config](../../operations/server-configuration-parameters/settings.md#users-config) and [access_control_path](../../operations/server-configuration-parameters/settings.md#access_control_path) won't be used.
+
+The `user_directories` section can contain any number of items, the order of the items means their precedence (the higher the item the higher the precedence).
+
+**Examples**
+
+``` xml
+<user_directories>
+    <users_xml>
+        <path>/etc/clickhouse-server/users.xml</path>
+    </users_xml>
+    <local_directory>
+        <path>/var/lib/clickhouse/access/</path>
+    </local_directory>
+</user_directories>
+```
+
+Users, roles, row policies, quotas, and profiles can be also stored in ZooKeeper:
+
+``` xml
+<user_directories>
+    <users_xml>
+        <path>/etc/clickhouse-server/users.xml</path>
+    </users_xml>
+    <replicated>
+        <zookeeper_path>/clickhouse/access/</zookeeper_path>
+    </replicated>
+</user_directories>
+```
+
+You can also define sections `memory` — means storing information only in memory, without writing to disk, and `ldap` — means storing information on an LDAP server.
+
+To add an LDAP server as a remote user directory of users that are not defined locally, define a single `ldap` section with a following parameters:
+-   `server` — one of LDAP server names defined in `ldap_servers` config section. This parameter is mandatory and cannot be empty.
+-   `roles` — section with a list of locally defined roles that will be assigned to each user retrieved from the LDAP server. If no roles are specified, user will not be able to perform any actions after authentication. If any of the listed roles is not defined locally at the time of authentication, the authentication attempt will fail as if the provided password was incorrect.
+
+**Example**
+
+``` xml
+<ldap>
+    <server>my_ldap_server</server>
+        <roles>
+            <my_local_role1 />
+            <my_local_role2 />
+        </roles>
+</ldap>
+```
+
+## total_memory_profiler_step {#total-memory-profiler-step}
+
+Sets the memory size (in bytes) for a stack trace at every peak allocation step. The data is stored in the [system.trace_log](../../operations/system-tables/trace_log.md) system table with `query_id` equal to an empty string.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `4194304`.
+
+## total_memory_tracker_sample_probability {#total-memory-tracker-sample-probability}
+
+Allows to collect random allocations and deallocations and writes them in the [system.trace_log](../../operations/system-tables/trace_log.md) system table with `trace_type` equal to a `MemorySample` with the specified probability. The probability is for every allocation or deallocations, regardless of the size of the allocation. Note that sampling happens only when the amount of untracked memory exceeds the untracked memory limit (default value is `4` MiB). It can be lowered if [total_memory_profiler_step](#total-memory-profiler-step) is lowered. You can set `total_memory_profiler_step` equal to `1` for extra fine-grained sampling.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Writing of random allocations and deallocations in the `system.trace_log` system table is disabled.
+
+Default value: `0`.
+
+## mmap_cache_size {#mmap-cache-size}
+
+Sets the cache size (in bytes) for mapped files. This setting allows to avoid frequent open/[mmap/munmap](https://en.wikipedia.org/wiki/Mmap)/close calls (which are very expensive due to consequent page faults) and to reuse mappings from several threads and queries. The setting value is the number of mapped regions (usually equal to the number of mapped files). The amount of data in mapped files can be monitored in [system.metrics](../../operations/system-tables/metrics.md), [system.metric_log](../../operations/system-tables/metric_log.md) system tables by the `MMappedFiles` and `MMappedFileBytes` metrics, in [system.asynchronous_metrics](../../operations/system-tables/asynchronous_metrics.md), [system.asynchronous_metrics_log](../../operations/system-tables/asynchronous_metric_log.md) by the `MMapCacheCells` metric, and also in [system.events](../../operations/system-tables/events.md), [system.processes](../../operations/system-tables/processes.md), [system.query_log](../../operations/system-tables/query_log.md), [system.query_thread_log](../../operations/system-tables/query_thread_log.md), [system.query_views_log](../../operations/system-tables/query_views_log.md) by the `CreatedReadBufferMMap`, `CreatedReadBufferMMapFailed`, `MMappedFileCacheHits`, `MMappedFileCacheMisses` events. Note that the amount of data in mapped files does not consume memory directly and is not accounted in query or server memory usage — because this memory can be discarded similar to OS page cache. The cache is dropped (the files are closed) automatically on the removal of old parts in tables of the [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) family, also it can be dropped manually by the `SYSTEM DROP MMAP CACHE` query.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `1000`.
+
+## compiled_expression_cache_size {#compiled-expression-cache-size}
+
+Sets the cache size (in bytes) for [compiled expressions](../../operations/caches.md).
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `134217728`.
+
+## compiled_expression_cache_elements_size {#compiled_expression_cache_elements_size}
+
+Sets the cache size (in elements) for [compiled expressions](../../operations/caches.md).
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `10000`.
+
diff --git a/docs/en/reference/operations/settings/constraints-on-settings.md b/docs/en/reference/operations/settings/constraints-on-settings.md
new file mode 100644
index 00000000000..5adde60a460
--- /dev/null
+++ b/docs/en/reference/operations/settings/constraints-on-settings.md
@@ -0,0 +1,73 @@
+---
+sidebar_position: 62
+sidebar_label: Constraints on Settings
+---
+
+# Constraints on Settings {#constraints-on-settings}
+
+The constraints on settings can be defined in the `profiles` section of the `user.xml` configuration file and prohibit users from changing some of the settings with the `SET` query.
+The constraints are defined as the following:
+
+``` xml
+<profiles>
+  <user_name>
+    <constraints>
+      <setting_name_1>
+        <min>lower_boundary</min>
+      </setting_name_1>
+      <setting_name_2>
+        <max>upper_boundary</max>
+      </setting_name_2>
+      <setting_name_3>
+        <min>lower_boundary</min>
+        <max>upper_boundary</max>
+      </setting_name_3>
+      <setting_name_4>
+        <readonly/>
+      </setting_name_4>
+    </constraints>
+  </user_name>
+</profiles>
+```
+
+If the user tries to violate the constraints an exception is thrown and the setting isn’t changed.
+There are supported three types of constraints: `min`, `max`, `readonly`. The `min` and `max` constraints specify upper and lower boundaries for a numeric setting and can be used in combination. The `readonly` constraint specifies that the user cannot change the corresponding setting at all.
+
+**Example:** Let `users.xml` includes lines:
+
+``` xml
+<profiles>
+  <default>
+    <max_memory_usage>10000000000</max_memory_usage>
+    <force_index_by_date>0</force_index_by_date>
+    ...
+    <constraints>
+      <max_memory_usage>
+        <min>5000000000</min>
+        <max>20000000000</max>
+      </max_memory_usage>
+      <force_index_by_date>
+        <readonly/>
+      </force_index_by_date>
+    </constraints>
+  </default>
+</profiles>
+```
+
+The following queries all throw exceptions:
+
+``` sql
+SET max_memory_usage=20000000001;
+SET max_memory_usage=4999999999;
+SET force_index_by_date=1;
+```
+
+``` text
+Code: 452, e.displayText() = DB::Exception: Setting max_memory_usage should not be greater than 20000000000.
+Code: 452, e.displayText() = DB::Exception: Setting max_memory_usage should not be less than 5000000000.
+Code: 452, e.displayText() = DB::Exception: Setting force_index_by_date should not be changed.
+```
+
+**Note:** the `default` profile has special handling: all the constraints defined for the `default` profile become the default constraints, so they restrict all the users until they’re overridden explicitly for these users.
+
+[Original article](https://clickhouse.com/docs/en/operations/settings/constraints_on_settings/) <!--hide-->
diff --git a/docs/en/reference/operations/settings/index.md b/docs/en/reference/operations/settings/index.md
new file mode 100644
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@@ -0,0 +1,58 @@
+---
+sidebar_label: Settings
+sidebar_position: 52
+slug: index
+---
+
+# Settings 
+
+There are multiple ways to make all the settings described in this section of documentation.
+
+Settings are configured in layers, so each subsequent layer redefines the previous settings.
+
+Ways to configure settings, in order of priority:
+
+-   Settings in the `users.xml` server configuration file.
+
+    Set in the element `<profiles>`.
+
+-   Session settings.
+
+    Send `SET setting=value` from the ClickHouse console client in interactive mode.
+    Similarly, you can use ClickHouse sessions in the HTTP protocol. To do this, you need to specify the `session_id` HTTP parameter.
+
+-   Query settings.
+
+    -   When starting the ClickHouse console client in non-interactive mode, set the startup parameter `--setting=value`.
+    -   When using the HTTP API, pass CGI parameters (`URL?setting_1=value&setting_2=value...`).
+    -   Make settings in the [SETTINGS](../../sql-reference/statements/select/index.md#settings-in-select) clause of the SELECT query. The setting value is applied only to that query and is reset to default or previous value after the query is executed.
+
+Settings that can only be made in the server config file are not covered in this section.
+
+## Custom Settings {#custom_settings}
+
+In addition to the common [settings](../../operations/settings/settings.md), users can define custom settings.
+
+A custom setting name must begin with one of predefined prefixes. The list of these prefixes must be declared in the [custom_settings_prefixes](../../operations/server-configuration-parameters/settings.md#custom_settings_prefixes) parameter in the server configuration file.
+
+```xml
+<custom_settings_prefixes>custom_</custom_settings_prefixes>
+```
+
+To define a custom setting use `SET` command:
+
+```sql
+SET custom_a = 123;
+```
+
+To get the current value of a custom setting use `getSetting()` function:
+
+```sql
+SELECT getSetting('custom_a');
+```
+
+**See Also**
+
+-   [Server Configuration Settings](../../operations/server-configuration-parameters/settings.md)
+
+[Original article](https://clickhouse.com/docs/en/operations/settings/) <!--hide-->
diff --git a/docs/en/reference/operations/settings/merge-tree-settings.md b/docs/en/reference/operations/settings/merge-tree-settings.md
new file mode 100644
index 00000000000..27a0578cce2
--- /dev/null
+++ b/docs/en/reference/operations/settings/merge-tree-settings.md
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+# MergeTree tables settings {#merge-tree-settings}
+
+The values of `merge_tree` settings (for all MergeTree tables) can be viewed in the table `system.merge_tree_settings`, they can be overridden in `config.xml` in the `merge_tree` section, or set in the `SETTINGS` section of each table.
+
+Override example in `config.xml`:
+
+``` text
+<merge_tree>
+    <max_suspicious_broken_parts>5</max_suspicious_broken_parts>
+</merge_tree>
+```
+
+An example to set in `SETTINGS` for a particular table:
+
+``` sql
+CREATE TABLE foo
+(
+    `A` Int64
+)
+ENGINE = MergeTree
+ORDER BY tuple()
+SETTINGS max_suspicious_broken_parts = 500;
+```
+
+An example of changing the settings for a specific table with the `ALTER TABLE ... MODIFY SETTING` command:
+
+``` sql
+ALTER TABLE foo
+    MODIFY SETTING max_suspicious_broken_parts = 100;
+    
+-- reset to default (use value from system.merge_tree_settings)
+ALTER TABLE foo
+    RESET SETTING max_suspicious_broken_parts;
+```
+
+## parts_to_throw_insert {#parts-to-throw-insert}
+
+If the number of active parts in a single partition exceeds the `parts_to_throw_insert` value, `INSERT` is interrupted with the `Too many parts (N). Merges are processing significantly slower than inserts` exception.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 300.
+
+To achieve maximum performance of `SELECT` queries, it is necessary to minimize the number of parts processed, see [Merge Tree](../../development/architecture.md#merge-tree).
+
+You can set a larger value to 600 (1200), this will reduce the probability of the `Too many parts` error, but at the same time `SELECT` performance might degrade. Also in case of a merge issue (for example, due to insufficient disk space) you will notice it later than it could be with the original 300.
+
+
+## parts_to_delay_insert {#parts-to-delay-insert}
+
+If the number of active parts in a single partition exceeds the `parts_to_delay_insert` value, an `INSERT` artificially slows down.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 150.
+
+ClickHouse artificially executes `INSERT` longer (adds ‘sleep’) so that the background merge process can merge parts faster than they are added.
+
+## inactive_parts_to_throw_insert {#inactive-parts-to-throw-insert}
+
+If the number of inactive parts in a single partition more than the `inactive_parts_to_throw_insert` value, `INSERT` is interrupted with the "Too many inactive parts (N). Parts cleaning are processing significantly slower than inserts" exception.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 0 (unlimited).
+
+## inactive_parts_to_delay_insert {#inactive-parts-to-delay-insert}
+
+If the number of inactive parts in a single partition in the table at least that many the `inactive_parts_to_delay_insert` value, an `INSERT` artificially slows down. It is useful when a server fails to clean up parts quickly enough.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 0 (unlimited).
+
+## max_delay_to_insert {#max-delay-to-insert}
+
+The value in seconds, which is used to calculate the `INSERT` delay, if the number of active parts in a single partition exceeds the [parts_to_delay_insert](#parts-to-delay-insert) value.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 1.
+
+The delay (in milliseconds) for `INSERT` is calculated by the formula:
+
+```code
+max_k = parts_to_throw_insert - parts_to_delay_insert
+k = 1 + parts_count_in_partition - parts_to_delay_insert
+delay_milliseconds = pow(max_delay_to_insert * 1000, k / max_k)
+```
+
+For example if a partition has 299 active parts and parts_to_throw_insert = 300, parts_to_delay_insert = 150, max_delay_to_insert = 1, `INSERT` is delayed for `pow( 1 * 1000, (1 + 299 - 150) / (300 - 150) ) = 1000` milliseconds.
+
+## max_parts_in_total {#max-parts-in-total}
+
+If the total number of active parts in all partitions of a table exceeds the `max_parts_in_total` value `INSERT` is interrupted with the `Too many parts (N)` exception.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 100000.
+
+A large number of parts in a table reduces performance of ClickHouse queries and increases ClickHouse boot time. Most often this is a consequence of an incorrect design (mistakes when choosing a partitioning strategy - too small partitions).
+
+## replicated_deduplication_window {#replicated-deduplication-window}
+
+The number of most recently inserted blocks for which Zookeeper stores hash sums to check for duplicates.
+
+Possible values:
+
+-   Any positive integer.
+-   0 (disable deduplication)
+
+Default value: 100.
+
+The `Insert` command creates one or more blocks (parts). When inserting into Replicated tables, ClickHouse for [insert deduplication](../../engines/table-engines/mergetree-family/replication/) writes the hash sums of the created parts into Zookeeper. Hash sums are stored only for the most recent `replicated_deduplication_window` blocks. The oldest hash sums are removed from Zookeeper.
+A large number of `replicated_deduplication_window` slows down `Inserts` because it needs to compare more entries.
+The hash sum is calculated from the composition of the field names and types and the data of the inserted part (stream of bytes).
+
+## non_replicated_deduplication_window {#non-replicated-deduplication-window}
+
+The number of the most recently inserted blocks in the non-replicated [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) table for which hash sums are stored to check for duplicates.
+
+Possible values:
+
+-   Any positive integer.
+-   0 (disable deduplication).
+
+Default value: 0.
+
+A deduplication mechanism is used, similar to replicated tables (see [replicated_deduplication_window](#replicated-deduplication-window) setting). The hash sums of the created parts are written to a local file on a disk.
+
+## replicated_deduplication_window_seconds {#replicated-deduplication-window-seconds}
+
+The number of seconds after which the hash sums of the inserted blocks are removed from Zookeeper.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 604800 (1 week).
+
+Similar to [replicated_deduplication_window](#replicated-deduplication-window), `replicated_deduplication_window_seconds` specifies how long to store hash sums of blocks for insert deduplication. Hash sums older than `replicated_deduplication_window_seconds` are removed from Zookeeper, even if they are less than ` replicated_deduplication_window`.
+
+## replicated_fetches_http_connection_timeout {#replicated_fetches_http_connection_timeout}
+
+HTTP connection timeout (in seconds) for part fetch requests. Inherited from default profile [http_connection_timeout](./settings.md#http_connection_timeout) if not set explicitly.
+
+Possible values:
+
+-   Any positive integer.
+-   0 - Use value of `http_connection_timeout`.
+
+Default value: 0.
+
+## replicated_fetches_http_send_timeout {#replicated_fetches_http_send_timeout}
+
+HTTP send timeout (in seconds) for part fetch requests. Inherited from default profile [http_send_timeout](./settings.md#http_send_timeout) if not set explicitly.
+
+Possible values:
+
+-   Any positive integer.
+-   0 - Use value of `http_send_timeout`.
+
+Default value: 0.
+
+## replicated_fetches_http_receive_timeout {#replicated_fetches_http_receive_timeout}
+
+HTTP receive timeout (in seconds) for fetch part requests. Inherited from default profile [http_receive_timeout](./settings.md#http_receive_timeout) if not set explicitly.
+
+Possible values:
+
+-   Any positive integer.
+-   0 - Use value of `http_receive_timeout`.
+
+Default value: 0.
+
+## max_replicated_fetches_network_bandwidth {#max_replicated_fetches_network_bandwidth}
+
+Limits the maximum speed of data exchange over the network in bytes per second for [replicated](../../engines/table-engines/mergetree-family/replication.md) fetches. This setting is applied to a particular table, unlike the [max_replicated_fetches_network_bandwidth_for_server](settings.md#max_replicated_fetches_network_bandwidth_for_server) setting, which is applied to the server.
+
+You can limit both server network and network for a particular table, but for this the value of the table-level setting should be less than server-level one. Otherwise the server considers only the `max_replicated_fetches_network_bandwidth_for_server` setting.
+
+The setting isn't followed perfectly accurately.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Unlimited.
+
+Default value: `0`.
+
+**Usage**
+
+Could be used for throttling speed when replicating data to add or replace new nodes.
+
+## max_replicated_sends_network_bandwidth {#max_replicated_sends_network_bandwidth}
+
+Limits the maximum speed of data exchange over the network in bytes per second for [replicated](../../engines/table-engines/mergetree-family/replication.md) sends. This setting is applied to a particular table, unlike the [max_replicated_sends_network_bandwidth_for_server](settings.md#max_replicated_sends_network_bandwidth_for_server) setting, which is applied to the server.
+
+You can limit both server network and network for a particular table, but for this the value of the table-level setting should be less than server-level one. Otherwise the server considers only the `max_replicated_sends_network_bandwidth_for_server` setting.
+
+The setting isn't followed perfectly accurately.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Unlimited.
+
+Default value: `0`.
+
+**Usage**
+
+Could be used for throttling speed when replicating data to add or replace new nodes.
+
+## old_parts_lifetime {#old-parts-lifetime}
+
+The time (in seconds) of storing inactive parts to protect against data loss during spontaneous server reboots.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 480.
+
+After merging several parts into a new part, ClickHouse marks the original parts as inactive and deletes them only after `old_parts_lifetime` seconds.
+Inactive parts are removed if they are not used by current queries, i.e. if the `refcount` of the part is zero.
+
+`fsync` is not called for new parts, so for some time new parts exist only in the server's RAM (OS cache). If the server is rebooted spontaneously, new parts can be lost or damaged.
+To protect data inactive parts are not deleted immediately.
+
+During startup ClickHouse checks the integrity of the parts.
+If the merged part is damaged ClickHouse returns the inactive parts to the active list, and later merges them again. Then the damaged part is renamed (the `broken_` prefix is added) and moved to the `detached` folder.
+If the merged part is not damaged, then the original inactive parts are renamed (the `ignored_` prefix is added) and moved to the `detached` folder.
+
+The default `dirty_expire_centisecs` value (a Linux kernel setting) is 30 seconds (the maximum time that written data is stored only in RAM), but under heavy loads on the disk system data can be written much later. Experimentally, a value of 480 seconds was chosen for `old_parts_lifetime`, during which a new part is guaranteed to be written to disk.
+
+## max_bytes_to_merge_at_max_space_in_pool {#max-bytes-to-merge-at-max-space-in-pool}
+
+The maximum total parts size (in bytes) to be merged into one part, if there are enough resources available.
+`max_bytes_to_merge_at_max_space_in_pool` -- roughly corresponds to the maximum possible part size created by an automatic background merge.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 161061273600 (150 GB).
+
+The merge scheduler periodically analyzes the sizes and number of parts in partitions, and if there is enough free resources in the pool, it starts background merges. Merges occur until the total size of the source parts is larger than `max_bytes_to_merge_at_max_space_in_pool`.
+
+Merges initiated by [OPTIMIZE FINAL](../../sql-reference/statements/optimize.md) ignore `max_bytes_to_merge_at_max_space_in_pool` and merge parts only taking into account available resources (free disk's space) until one part remains in the partition.
+
+## max_bytes_to_merge_at_min_space_in_pool {#max-bytes-to-merge-at-min-space-in-pool}
+
+The maximum total part size (in bytes) to be merged into one part, with the minimum available resources in the background pool.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 1048576 (1 MB)
+
+`max_bytes_to_merge_at_min_space_in_pool` defines the maximum total size of parts which can be merged despite the lack of available disk space (in pool). This is necessary to reduce the number of small parts and the chance of `Too many parts` errors.
+Merges book disk space by doubling the total merged parts sizes. Thus, with a small amount of free disk space, a situation may happen that there is free space, but this space is already booked by ongoing large merges, so other merges unable to start, and the number of small parts grows with every insert.
+
+## merge_max_block_size {#merge-max-block-size}
+
+The number of rows that are read from the merged parts into memory.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 8192
+
+Merge reads rows from parts in blocks of `merge_max_block_size` rows, then merges and writes the result into a new part. The read block is placed in RAM, so `merge_max_block_size` affects the size of the RAM required for the merge. Thus, merges can consume a large amount of RAM for tables with very wide rows (if the average row size is 100kb, then when merging 10 parts, (100kb * 10 * 8192) = ~ 8GB of RAM). By decreasing `merge_max_block_size`, you can reduce the amount of RAM required for a merge but slow down a merge.
+
+## max_part_loading_threads {#max-part-loading-threads}
+
+The maximum number of threads that read parts when ClickHouse starts.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: auto (number of CPU cores).
+
+During startup ClickHouse reads all parts of all tables (reads files with metadata of parts) to build a list of all parts in memory. In some systems with a large number of parts this process can take a long time, and this time might be shortened by increasing `max_part_loading_threads` (if this process is not CPU and disk I/O bound).
+
+## max_partitions_to_read {#max-partitions-to-read}
+
+Limits the maximum number of partitions that can be accessed in one query.
+
+The setting value specified when the table is created can be overridden via query-level setting.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: -1 (unlimited).
+
+## allow_floating_point_partition_key {#allow_floating_point_partition_key}
+
+Enables to allow floating-point number as a partition key.
+
+Possible values:
+
+-   0 — Floating-point partition key not allowed.
+-   1 — Floating-point partition key allowed.
+
+Default value: `0`.
+
+## check_sample_column_is_correct {#check_sample_column_is_correct}
+
+Enables the check at table creation, that the data type of a column for sampling or sampling expression is correct. The data type must be one of unsigned [integer types](../../sql-reference/data-types/int-uint.md): `UInt8`, `UInt16`, `UInt32`, `UInt64`.
+
+Possible values:
+
+-   true  — The check is enabled.
+-   false — The check is disabled at table creation.
+
+Default value: `true`.
+
+By default, the ClickHouse server checks at table creation the data type of a column for sampling or sampling expression. If you already have tables with incorrect sampling expression and do not want the server to raise an exception during startup, set `check_sample_column_is_correct` to `false`.
+
+## min_bytes_to_rebalance_partition_over_jbod {#min-bytes-to-rebalance-partition-over-jbod}
+
+Sets minimal amount of bytes to enable balancing when distributing new big parts over volume disks [JBOD](https://en.wikipedia.org/wiki/Non-RAID_drive_architectures).
+
+Possible values:
+
+-   Positive integer.
+-   0 — Balancing is disabled.
+
+Default value: `0`.
+
+**Usage**
+
+The value of the `min_bytes_to_rebalance_partition_over_jbod` setting should not be less than the value of the [max_bytes_to_merge_at_max_space_in_pool](../../operations/settings/merge-tree-settings.md#max-bytes-to-merge-at-max-space-in-pool) / 1024. Otherwise, ClickHouse throws an exception.
+
+## detach_not_byte_identical_parts {#detach_not_byte_identical_parts}
+
+Enables or disables detaching a data part on a replica after a merge or a mutation, if it is not byte-identical to data parts on other replicas. If disabled, the data part is removed. Activate this setting if you want to analyze such parts later.
+
+The setting is applicable to `MergeTree` tables with enabled [data replication](../../engines/table-engines/mergetree-family/replication.md).
+
+Possible values:
+
+-   0 — Parts are removed.
+-   1 — Parts are detached.
+
+Default value: `0`.
+
+## merge_tree_clear_old_temporary_directories_interval_seconds {#setting-merge-tree-clear-old-temporary-directories-interval-seconds}
+
+Sets the interval in seconds for ClickHouse to execute the cleanup of old temporary directories.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: `60` seconds.
+
+## merge_tree_clear_old_parts_interval_seconds {#setting-merge-tree-clear-old-parts-interval-seconds}
+
+Sets the interval in seconds for ClickHouse to execute the cleanup of old parts, WALs, and mutations.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: `1` second.
+
diff --git a/docs/en/reference/operations/settings/permissions-for-queries.md b/docs/en/reference/operations/settings/permissions-for-queries.md
new file mode 100644
index 00000000000..ff63f524b7d
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+++ b/docs/en/reference/operations/settings/permissions-for-queries.md
@@ -0,0 +1,59 @@
+---
+sidebar_position: 58
+sidebar_label: Permissions for Queries
+---
+
+# Permissions for Queries {#permissions_for_queries}
+
+Queries in ClickHouse can be divided into several types:
+
+1.  Read data queries: `SELECT`, `SHOW`, `DESCRIBE`, `EXISTS`.
+2.  Write data queries: `INSERT`, `OPTIMIZE`.
+3.  Change settings query: `SET`, `USE`.
+4.  [DDL](https://en.wikipedia.org/wiki/Data_definition_language) queries: `CREATE`, `ALTER`, `RENAME`, `ATTACH`, `DETACH`, `DROP` `TRUNCATE`.
+5.  `KILL QUERY`.
+
+The following settings regulate user permissions by the type of query:
+
+-   [readonly](#settings_readonly) — Restricts permissions for all types of queries except DDL queries.
+-   [allow_ddl](#settings_allow_ddl) — Restricts permissions for DDL queries.
+
+`KILL QUERY` can be performed with any settings.
+
+## readonly {#settings_readonly}
+
+Restricts permissions for reading data, write data and change settings queries.
+
+See how the queries are divided into types [above](#permissions_for_queries).
+
+Possible values:
+
+-   0 — All queries are allowed.
+-   1 — Only read data queries are allowed.
+-   2 — Read data and change settings queries are allowed.
+
+After setting `readonly = 1`, the user can’t change `readonly` and `allow_ddl` settings in the current session.
+
+When using the `GET` method in the [HTTP interface](../../interfaces/http.md), `readonly = 1` is set automatically. To modify data, use the `POST` method.
+
+Setting `readonly = 1` prohibit the user from changing all the settings. There is a way to prohibit the user
+from changing only specific settings, for details see [constraints on settings](../../operations/settings/constraints-on-settings.md).
+
+Default value: 0
+
+## allow_ddl {#settings_allow_ddl}
+
+Allows or denies [DDL](https://en.wikipedia.org/wiki/Data_definition_language) queries.
+
+See how the queries are divided into types [above](#permissions_for_queries).
+
+Possible values:
+
+-   0 — DDL queries are not allowed.
+-   1 — DDL queries are allowed.
+
+You can’t execute `SET allow_ddl = 1` if `allow_ddl = 0` for the current session.
+
+Default value: 1
+
+[Original article](https://clickhouse.com/docs/en/operations/settings/permissions_for_queries/) <!--hide-->
diff --git a/docs/en/reference/operations/settings/query-complexity.md b/docs/en/reference/operations/settings/query-complexity.md
new file mode 100644
index 00000000000..c0c77bc809a
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@@ -0,0 +1,315 @@
+---
+sidebar_position: 59
+sidebar_label: Restrictions on Query Complexity
+---
+
+# Restrictions on Query Complexity {#restrictions-on-query-complexity}
+
+Restrictions on query complexity are part of the settings.
+They are used to provide safer execution from the user interface.
+Almost all the restrictions only apply to `SELECT`. For distributed query processing, restrictions are applied on each server separately.
+
+ClickHouse checks the restrictions for data parts, not for each row. It means that you can exceed the value of restriction with the size of the data part.
+
+Restrictions on the “maximum amount of something” can take the value 0, which means “unrestricted”.
+Most restrictions also have an ‘overflow_mode’ setting, meaning what to do when the limit is exceeded.
+It can take one of two values: `throw` or `break`. Restrictions on aggregation (group_by_overflow_mode) also have the value `any`.
+
+`throw` – Throw an exception (default).
+
+`break` – Stop executing the query and return the partial result, as if the source data ran out.
+
+`any (only for group_by_overflow_mode)` – Continuing aggregation for the keys that got into the set, but do not add new keys to the set.
+
+## max_memory_usage {#settings_max_memory_usage}
+
+The maximum amount of RAM to use for running a query on a single server.
+
+In the default configuration file, the maximum is 10 GB.
+
+The setting does not consider the volume of available memory or the total volume of memory on the machine.
+The restriction applies to a single query within a single server.
+You can use `SHOW PROCESSLIST` to see the current memory consumption for each query.
+Besides, the peak memory consumption is tracked for each query and written to the log.
+
+Memory usage is not monitored for the states of certain aggregate functions.
+
+Memory usage is not fully tracked for states of the aggregate functions `min`, `max`, `any`, `anyLast`, `argMin`, `argMax` from `String` and `Array` arguments.
+
+Memory consumption is also restricted by the parameters `max_memory_usage_for_user` and [max_server_memory_usage](../../operations/server-configuration-parameters/settings.md#max_server_memory_usage).
+
+## max_memory_usage_for_user {#max-memory-usage-for-user}
+
+The maximum amount of RAM to use for running a user’s queries on a single server.
+
+Default values are defined in [Settings.h](https://github.com/ClickHouse/ClickHouse/blob/master/src/Core/Settings.h#L288). By default, the amount is not restricted (`max_memory_usage_for_user = 0`).
+
+See also the description of [max_memory_usage](#settings_max_memory_usage).
+
+## max_rows_to_read {#max-rows-to-read}
+
+The following restrictions can be checked on each block (instead of on each row). That is, the restrictions can be broken a little.
+
+A maximum number of rows that can be read from a table when running a query.
+
+## max_bytes_to_read {#max-bytes-to-read}
+
+A maximum number of bytes (uncompressed data) that can be read from a table when running a query.
+
+## read_overflow_mode {#read-overflow-mode}
+
+What to do when the volume of data read exceeds one of the limits: ‘throw’ or ‘break’. By default, throw.
+
+## max_rows_to_read_leaf {#max-rows-to-read-leaf}
+
+The following restrictions can be checked on each block (instead of on each row). That is, the restrictions can be broken a little.
+
+A maximum number of rows that can be read from a local table on a leaf node when running a distributed query. While
+distributed queries can issue a multiple sub-queries to each shard (leaf) - this limit will be checked only on the read
+stage on the leaf nodes and ignored on results merging stage on the root node. For example, cluster consists of 2 shards
+and each shard contains a table with 100 rows. Then distributed query which suppose to read all the data from both
+tables with setting `max_rows_to_read=150` will fail as in total it will be 200 rows. While query
+with `max_rows_to_read_leaf=150` will succeed since leaf nodes will read 100 rows at max.
+
+## max_bytes_to_read_leaf {#max-bytes-to-read-leaf}
+
+A maximum number of bytes (uncompressed data) that can be read from a local table on a leaf node when running
+a distributed query. While distributed queries can issue a multiple sub-queries to each shard (leaf) - this limit will
+be checked only on the read stage on the leaf nodes and ignored on results merging stage on the root node.
+For example, cluster consists of 2 shards and each shard contains a table with 100 bytes of data.
+Then distributed query which suppose to read all the data from both tables with setting `max_bytes_to_read=150` will fail
+as in total it will be 200 bytes. While query with `max_bytes_to_read_leaf=150` will succeed since leaf nodes will read
+100 bytes at max.
+
+## read_overflow_mode_leaf {#read-overflow-mode-leaf}
+
+What to do when the volume of data read exceeds one of the leaf limits: ‘throw’ or ‘break’. By default, throw.
+
+## max_rows_to_group_by {#settings-max-rows-to-group-by}
+
+A maximum number of unique keys received from aggregation. This setting lets you limit memory consumption when aggregating.
+
+## group_by_overflow_mode {#group-by-overflow-mode}
+
+What to do when the number of unique keys for aggregation exceeds the limit: ‘throw’, ‘break’, or ‘any’. By default, throw.
+Using the ‘any’ value lets you run an approximation of GROUP BY. The quality of this approximation depends on the statistical nature of the data.
+
+## max_bytes_before_external_group_by {#settings-max_bytes_before_external_group_by}
+
+Enables or disables execution of `GROUP BY` clauses in external memory. See [GROUP BY in external memory](../../sql-reference/statements/select/group-by.md#select-group-by-in-external-memory).
+
+Possible values:
+
+-   Maximum volume of RAM (in bytes) that can be used by the single [GROUP BY](../../sql-reference/statements/select/group-by.md#select-group-by-clause) operation.
+-   0 — `GROUP BY` in external memory disabled.
+
+Default value: 0.
+
+## max_rows_to_sort {#max-rows-to-sort}
+
+A maximum number of rows before sorting. This allows you to limit memory consumption when sorting.
+
+## max_bytes_to_sort {#max-bytes-to-sort}
+
+A maximum number of bytes before sorting.
+
+## sort_overflow_mode {#sort-overflow-mode}
+
+What to do if the number of rows received before sorting exceeds one of the limits: ‘throw’ or ‘break’. By default, throw.
+
+## max_result_rows {#setting-max_result_rows}
+
+Limit on the number of rows in the result. Also checked for subqueries, and on remote servers when running parts of a distributed query.
+
+## max_result_bytes {#max-result-bytes}
+
+Limit on the number of bytes in the result. The same as the previous setting.
+
+## result_overflow_mode {#result-overflow-mode}
+
+What to do if the volume of the result exceeds one of the limits: ‘throw’ or ‘break’. By default, throw.
+
+Using ‘break’ is similar to using LIMIT. `Break` interrupts execution only at the block level. This means that amount of returned rows is greater than [max_result_rows](#setting-max_result_rows), multiple of [max_block_size](../../operations/settings/settings.md#setting-max_block_size) and depends on [max_threads](../../operations/settings/settings.md#settings-max_threads).
+
+Example:
+
+``` sql
+SET max_threads = 3, max_block_size = 3333;
+SET max_result_rows = 3334, result_overflow_mode = 'break';
+
+SELECT *
+FROM numbers_mt(100000)
+FORMAT Null;
+```
+
+Result:
+
+``` text
+6666 rows in set. ...
+```
+
+## max_execution_time {#max-execution-time}
+
+Maximum query execution time in seconds.
+At this time, it is not checked for one of the sorting stages, or when merging and finalizing aggregate functions.
+
+## timeout_overflow_mode {#timeout-overflow-mode}
+
+What to do if the query is run longer than ‘max_execution_time’: ‘throw’ or ‘break’. By default, throw.
+
+## min_execution_speed {#min-execution-speed}
+
+Minimal execution speed in rows per second. Checked on every data block when ‘timeout_before_checking_execution_speed’ expires. If the execution speed is lower, an exception is thrown.
+
+## min_execution_speed_bytes {#min-execution-speed-bytes}
+
+A minimum number of execution bytes per second. Checked on every data block when ‘timeout_before_checking_execution_speed’ expires. If the execution speed is lower, an exception is thrown.
+
+## max_execution_speed {#max-execution-speed}
+
+A maximum number of execution rows per second. Checked on every data block when ‘timeout_before_checking_execution_speed’ expires. If the execution speed is high, the execution speed will be reduced.
+
+## max_execution_speed_bytes {#max-execution-speed-bytes}
+
+A maximum number of execution bytes per second. Checked on every data block when ‘timeout_before_checking_execution_speed’ expires. If the execution speed is high, the execution speed will be reduced.
+
+## timeout_before_checking_execution_speed {#timeout-before-checking-execution-speed}
+
+Checks that execution speed is not too slow (no less than ‘min_execution_speed’), after the specified time in seconds has expired.
+
+## max_columns_to_read {#max-columns-to-read}
+
+A maximum number of columns that can be read from a table in a single query. If a query requires reading a greater number of columns, it throws an exception.
+
+## max_temporary_columns {#max-temporary-columns}
+
+A maximum number of temporary columns that must be kept in RAM at the same time when running a query, including constant columns. If there are more temporary columns than this, it throws an exception.
+
+## max_temporary_non_const_columns {#max-temporary-non-const-columns}
+
+The same thing as ‘max_temporary_columns’, but without counting constant columns.
+Note that constant columns are formed fairly often when running a query, but they require approximately zero computing resources.
+
+## max_subquery_depth {#max-subquery-depth}
+
+Maximum nesting depth of subqueries. If subqueries are deeper, an exception is thrown. By default, 100.
+
+## max_pipeline_depth {#max-pipeline-depth}
+
+Maximum pipeline depth. Corresponds to the number of transformations that each data block goes through during query processing. Counted within the limits of a single server. If the pipeline depth is greater, an exception is thrown. By default, 1000.
+
+## max_ast_depth {#max-ast-depth}
+
+Maximum nesting depth of a query syntactic tree. If exceeded, an exception is thrown.
+At this time, it isn’t checked during parsing, but only after parsing the query. That is, a syntactic tree that is too deep can be created during parsing, but the query will fail. By default, 1000.
+
+## max_ast_elements {#max-ast-elements}
+
+A maximum number of elements in a query syntactic tree. If exceeded, an exception is thrown.
+In the same way as the previous setting, it is checked only after parsing the query. By default, 50,000.
+
+## max_rows_in_set {#max-rows-in-set}
+
+A maximum number of rows for a data set in the IN clause created from a subquery.
+
+## max_bytes_in_set {#max-bytes-in-set}
+
+A maximum number of bytes (uncompressed data) used by a set in the IN clause created from a subquery.
+
+## set_overflow_mode {#set-overflow-mode}
+
+What to do when the amount of data exceeds one of the limits: ‘throw’ or ‘break’. By default, throw.
+
+## max_rows_in_distinct {#max-rows-in-distinct}
+
+A maximum number of different rows when using DISTINCT.
+
+## max_bytes_in_distinct {#max-bytes-in-distinct}
+
+A maximum number of bytes used by a hash table when using DISTINCT.
+
+## distinct_overflow_mode {#distinct-overflow-mode}
+
+What to do when the amount of data exceeds one of the limits: ‘throw’ or ‘break’. By default, throw.
+
+## max_rows_to_transfer {#max-rows-to-transfer}
+
+A maximum number of rows that can be passed to a remote server or saved in a temporary table when using GLOBAL IN.
+
+## max_bytes_to_transfer {#max-bytes-to-transfer}
+
+A maximum number of bytes (uncompressed data) that can be passed to a remote server or saved in a temporary table when using GLOBAL IN.
+
+## transfer_overflow_mode {#transfer-overflow-mode}
+
+What to do when the amount of data exceeds one of the limits: ‘throw’ or ‘break’. By default, throw.
+
+## max_rows_in_join {#settings-max_rows_in_join}
+
+Limits the number of rows in the hash table that is used when joining tables.
+
+This settings applies to [SELECT … JOIN](../../sql-reference/statements/select/join.md#select-join) operations and the [Join](../../engines/table-engines/special/join.md) table engine.
+
+If a query contains multiple joins, ClickHouse checks this setting for every intermediate result.
+
+ClickHouse can proceed with different actions when the limit is reached. Use the [join_overflow_mode](#settings-join_overflow_mode) setting to choose the action.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Unlimited number of rows.
+
+Default value: 0.
+
+## max_bytes_in_join {#settings-max_bytes_in_join}
+
+Limits the size in bytes of the hash table used when joining tables.
+
+This settings applies to [SELECT … JOIN](../../sql-reference/statements/select/join.md#select-join) operations and [Join table engine](../../engines/table-engines/special/join.md).
+
+If the query contains joins, ClickHouse checks this setting for every intermediate result.
+
+ClickHouse can proceed with different actions when the limit is reached. Use [join_overflow_mode](#settings-join_overflow_mode) settings to choose the action.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Memory control is disabled.
+
+Default value: 0.
+
+## join_overflow_mode {#settings-join_overflow_mode}
+
+Defines what action ClickHouse performs when any of the following join limits is reached:
+
+-   [max_bytes_in_join](#settings-max_bytes_in_join)
+-   [max_rows_in_join](#settings-max_rows_in_join)
+
+Possible values:
+
+-   `THROW` — ClickHouse throws an exception and breaks operation.
+-   `BREAK` — ClickHouse breaks operation and does not throw an exception.
+
+Default value: `THROW`.
+
+**See Also**
+
+-   [JOIN clause](../../sql-reference/statements/select/join.md#select-join)
+-   [Join table engine](../../engines/table-engines/special/join.md)
+
+## max_partitions_per_insert_block {#max-partitions-per-insert-block}
+
+Limits the maximum number of partitions in a single inserted block.
+
+-   Positive integer.
+-   0 — Unlimited number of partitions.
+
+Default value: 100.
+
+**Details**
+
+When inserting data, ClickHouse calculates the number of partitions in the inserted block. If the number of partitions is more than `max_partitions_per_insert_block`, ClickHouse throws an exception with the following text:
+
+> “Too many partitions for single INSERT block (more than” + toString(max_parts) + “). The limit is controlled by ‘max_partitions_per_insert_block’ setting. A large number of partitions is a common misconception. It will lead to severe negative performance impact, including slow server startup, slow INSERT queries and slow SELECT queries. Recommended total number of partitions for a table is under 1000..10000. Please note, that partitioning is not intended to speed up SELECT queries (ORDER BY key is sufficient to make range queries fast). Partitions are intended for data manipulation (DROP PARTITION, etc).”
+
+[Original article](https://clickhouse.com/docs/en/operations/settings/query_complexity/) <!--hide-->
diff --git a/docs/en/reference/operations/settings/settings-profiles.md b/docs/en/reference/operations/settings/settings-profiles.md
new file mode 100644
index 00000000000..b8e1e3c21c4
--- /dev/null
+++ b/docs/en/reference/operations/settings/settings-profiles.md
@@ -0,0 +1,80 @@
+---
+sidebar_position: 61
+sidebar_label: Settings Profiles
+---
+
+# Settings Profiles {#settings-profiles}
+
+A settings profile is a collection of settings grouped under the same name.
+
+:::note
+ClickHouse also supports [SQL-driven workflow](../../operations/access-rights.md#access-control) for managing settings profiles. We recommend using it.
+:::
+
+The profile can have any name. You can specify the same profile for different users. The most important thing you can write in the settings profile is `readonly=1`, which ensures read-only access.
+
+Settings profiles can inherit from each other. To use inheritance, indicate one or multiple `profile` settings before the other settings that are listed in the profile. In case when one setting is defined in different profiles, the latest defined is used.
+
+To apply all the settings in a profile, set the `profile` setting.
+
+Example:
+
+Install the `web` profile.
+
+``` sql
+SET profile = 'web'
+```
+
+Settings profiles are declared in the user config file. This is usually `users.xml`.
+
+Example:
+
+``` xml
+<!-- Settings profiles -->
+<profiles>
+    <!-- Default settings -->
+    <default>
+        <!-- The maximum number of threads when running a single query. -->
+        <max_threads>8</max_threads>
+    </default>
+
+    <!-- Settings for quries from the user interface -->
+    <web>
+        <max_rows_to_read>1000000000</max_rows_to_read>
+        <max_bytes_to_read>100000000000</max_bytes_to_read>
+
+        <max_rows_to_group_by>1000000</max_rows_to_group_by>
+        <group_by_overflow_mode>any</group_by_overflow_mode>
+
+        <max_rows_to_sort>1000000</max_rows_to_sort>
+        <max_bytes_to_sort>1000000000</max_bytes_to_sort>
+
+        <max_result_rows>100000</max_result_rows>
+        <max_result_bytes>100000000</max_result_bytes>
+        <result_overflow_mode>break</result_overflow_mode>
+
+        <max_execution_time>600</max_execution_time>
+        <min_execution_speed>1000000</min_execution_speed>
+        <timeout_before_checking_execution_speed>15</timeout_before_checking_execution_speed>
+
+        <max_columns_to_read>25</max_columns_to_read>
+        <max_temporary_columns>100</max_temporary_columns>
+        <max_temporary_non_const_columns>50</max_temporary_non_const_columns>
+
+        <max_subquery_depth>2</max_subquery_depth>
+        <max_pipeline_depth>25</max_pipeline_depth>
+        <max_ast_depth>50</max_ast_depth>
+        <max_ast_elements>100</max_ast_elements>
+
+        <readonly>1</readonly>
+    </web>
+</profiles>
+```
+
+The example specifies two profiles: `default` and `web`.
+
+The `default` profile has a special purpose: it must always be present and is applied when starting the server. In other words, the `default` profile contains default settings.
+
+The `web` profile is a regular profile that can be set using the `SET` query or using a URL parameter in an HTTP query.
+
+[Original article](https://clickhouse.com/docs/en/operations/settings/settings_profiles/) <!--hide-->
diff --git a/docs/en/reference/operations/settings/settings-users.md b/docs/en/reference/operations/settings/settings-users.md
new file mode 100644
index 00000000000..6a020be2afc
--- /dev/null
+++ b/docs/en/reference/operations/settings/settings-users.md
@@ -0,0 +1,164 @@
+---
+sidebar_position: 63
+sidebar_label: User Settings
+---
+
+# User Settings {#user-settings}
+
+The `users` section of the `user.xml` configuration file contains user settings.
+
+:::note
+ClickHouse also supports [SQL-driven workflow](../../operations/access-rights.md#access-control) for managing users. We recommend using it.
+:::
+
+Structure of the `users` section:
+
+``` xml
+<users>
+    <!-- If user name was not specified, 'default' user is used. -->
+    <user_name>
+        <password></password>
+        <!-- Or -->
+        <password_sha256_hex></password_sha256_hex>
+
+        <access_management>0|1</access_management>
+
+        <networks incl="networks" replace="replace">
+        </networks>
+
+        <profile>profile_name</profile>
+
+        <quota>default</quota>
+        <default_database>default<default_database>
+        <databases>
+            <database_name>
+                <table_name>
+                    <filter>expression</filter>
+                <table_name>
+            </database_name>
+        </databases>
+    </user_name>
+    <!-- Other users settings -->
+</users>
+```
+
+### user_name/password {#user-namepassword}
+
+Password can be specified in plaintext or in SHA256 (hex format).
+
+-   To assign a password in plaintext (**not recommended**), place it in a `password` element.
+
+    For example, `<password>qwerty</password>`. The password can be left blank.
+
+<a id="password_sha256_hex"></a>
+
+-   To assign a password using its SHA256 hash, place it in a `password_sha256_hex` element.
+
+    For example, `<password_sha256_hex>65e84be33532fb784c48129675f9eff3a682b27168c0ea744b2cf58ee02337c5</password_sha256_hex>`.
+
+    Example of how to generate a password from shell:
+
+          PASSWORD=$(base64 < /dev/urandom | head -c8); echo "$PASSWORD"; echo -n "$PASSWORD" | sha256sum | tr -d '-'
+
+    The first line of the result is the password. The second line is the corresponding SHA256 hash.
+
+<a id="password_double_sha1_hex"></a>
+
+-   For compatibility with MySQL clients, password can be specified in double SHA1 hash. Place it in `password_double_sha1_hex` element.
+
+    For example, `<password_double_sha1_hex>08b4a0f1de6ad37da17359e592c8d74788a83eb0</password_double_sha1_hex>`.
+
+    Example of how to generate a password from shell:
+
+          PASSWORD=$(base64 < /dev/urandom | head -c8); echo "$PASSWORD"; echo -n "$PASSWORD" | sha1sum | tr -d '-' | xxd -r -p | sha1sum | tr -d '-'
+
+    The first line of the result is the password. The second line is the corresponding double SHA1 hash.
+
+### access_management {#access_management-user-setting}
+
+This setting enables or disables using of SQL-driven [access control and account management](../../operations/access-rights.md#access-control) for the user.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+### user_name/networks {#user-namenetworks}
+
+List of networks from which the user can connect to the ClickHouse server.
+
+Each element of the list can have one of the following forms:
+
+-   `<ip>` — IP address or network mask.
+
+    Examples: `213.180.204.3`, `10.0.0.1/8`, `10.0.0.1/255.255.255.0`, `2a02:6b8::3`, `2a02:6b8::3/64`, `2a02:6b8::3/ffff:ffff:ffff:ffff::`.
+
+-   `<host>` — Hostname.
+
+    Example: `example01.host.ru`.
+
+    To check access, a DNS query is performed, and all returned IP addresses are compared to the peer address.
+
+-   `<host_regexp>` — Regular expression for hostnames.
+
+    Example, `^example\d\d-\d\d-\d\.host\.ru$`
+
+    To check access, a [DNS PTR query](https://en.wikipedia.org/wiki/Reverse_DNS_lookup) is performed for the peer address and then the specified regexp is applied. Then, another DNS query is performed for the results of the PTR query and all the received addresses are compared to the peer address. We strongly recommend that regexp ends with $.
+
+All results of DNS requests are cached until the server restarts.
+
+**Examples**
+
+To open access for user from any network, specify:
+
+``` xml
+<ip>::/0</ip>
+```
+
+:::warning
+It’s insecure to open access from any network unless you have a firewall properly configured or the server is not directly connected to Internet.
+:::
+
+To open access only from localhost, specify:
+
+``` xml
+<ip>::1</ip>
+<ip>127.0.0.1</ip>
+```
+
+### user_name/profile {#user-nameprofile}
+
+You can assign a settings profile for the user. Settings profiles are configured in a separate section of the `users.xml` file. For more information, see [Profiles of Settings](../../operations/settings/settings-profiles.md).
+
+### user_name/quota {#user-namequota}
+
+Quotas allow you to track or limit resource usage over a period of time. Quotas are configured in the `quotas`
+section of the `users.xml` configuration file.
+
+You can assign a quotas set for the user. For a detailed description of quotas configuration, see [Quotas](../../operations/quotas.md#quotas).
+
+### user_name/databases {#user-namedatabases}
+
+In this section, you can limit rows that are returned by ClickHouse for `SELECT` queries made by the current user, thus implementing basic row-level security.
+
+**Example**
+
+The following configuration forces that user `user1` can only see the rows of `table1` as the result of `SELECT` queries, where the value of the `id` field is 1000.
+
+``` xml
+<user1>
+    <databases>
+        <database_name>
+            <table1>
+                <filter>id = 1000</filter>
+            </table1>
+        </database_name>
+    </databases>
+</user1>
+```
+
+The `filter` can be any expression resulting in a [UInt8](../../sql-reference/data-types/int-uint.md)-type value. It usually contains comparisons and logical operators. Rows from `database_name.table1` where filter results to 0 are not returned for this user. The filtering is incompatible with `PREWHERE` operations and disables `WHERE→PREWHERE` optimization.
+
+[Original article](https://clickhouse.com/docs/en/operations/settings/settings_users/) <!--hide-->
diff --git a/docs/en/reference/operations/settings/settings.md b/docs/en/reference/operations/settings/settings.md
new file mode 100644
index 00000000000..30d7dd98ee7
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@@ -0,0 +1,4232 @@
+# Settings {#settings}
+
+## distributed_product_mode {#distributed-product-mode}
+
+Changes the behaviour of [distributed subqueries](../../sql-reference/operators/in.md).
+
+ClickHouse applies this setting when the query contains the product of distributed tables, i.e. when the query for a distributed table contains a non-GLOBAL subquery for the distributed table.
+
+Restrictions:
+
+-   Only applied for IN and JOIN subqueries.
+-   Only if the FROM section uses a distributed table containing more than one shard.
+-   If the subquery concerns a distributed table containing more than one shard.
+-   Not used for a table-valued [remote](../../sql-reference/table-functions/remote.md) function.
+
+Possible values:
+
+-   `deny` — Default value. Prohibits using these types of subqueries (returns the “Double-distributed in/JOIN subqueries is denied” exception).
+-   `local` — Replaces the database and table in the subquery with local ones for the destination server (shard), leaving the normal `IN`/`JOIN.`
+-   `global` — Replaces the `IN`/`JOIN` query with `GLOBAL IN`/`GLOBAL JOIN.`
+-   `allow` — Allows the use of these types of subqueries.
+
+## prefer_global_in_and_join {#prefer-global-in-and-join}
+
+Enables the replacement of `IN`/`JOIN` operators with `GLOBAL IN`/`GLOBAL JOIN`.
+
+Possible values:
+
+-   0 — Disabled. `IN`/`JOIN` operators are not replaced with `GLOBAL IN`/`GLOBAL JOIN`.
+-   1 — Enabled. `IN`/`JOIN` operators are replaced with `GLOBAL IN`/`GLOBAL JOIN`.
+
+Default value: `0`.
+
+**Usage**
+
+Although `SET distributed_product_mode=global` can change the queries behavior for the distributed tables, it's not suitable for local tables or tables from external resources. Here is when the `prefer_global_in_and_join` setting comes into play.
+
+For example, we have query serving nodes that contain local tables, which are not suitable for distribution. We need to scatter their data on the fly during distributed processing with the `GLOBAL` keyword — `GLOBAL IN`/`GLOBAL JOIN`.
+
+Another use case of `prefer_global_in_and_join` is accessing tables created by external engines. This setting helps to reduce the number of calls to external sources while joining such tables: only one call per query.
+
+**See also:**
+
+-   [Distributed subqueries](../../sql-reference/operators/in.md#select-distributed-subqueries) for more information on how to use `GLOBAL IN`/`GLOBAL JOIN`
+
+## enable_optimize_predicate_expression {#enable-optimize-predicate-expression}
+
+Turns on predicate pushdown in `SELECT` queries.
+
+Predicate pushdown may significantly reduce network traffic for distributed queries.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1.
+
+Usage
+
+Consider the following queries:
+
+1.  `SELECT count() FROM test_table WHERE date = '2018-10-10'`
+2.  `SELECT count() FROM (SELECT * FROM test_table) WHERE date = '2018-10-10'`
+
+If `enable_optimize_predicate_expression = 1`, then the execution time of these queries is equal because ClickHouse applies `WHERE` to the subquery when processing it.
+
+If `enable_optimize_predicate_expression = 0`, then the execution time of the second query is much longer because the `WHERE` clause applies to all the data after the subquery finishes.
+
+## fallback_to_stale_replicas_for_distributed_queries {#settings-fallback_to_stale_replicas_for_distributed_queries}
+
+Forces a query to an out-of-date replica if updated data is not available. See [Replication](../../engines/table-engines/mergetree-family/replication.md).
+
+ClickHouse selects the most relevant from the outdated replicas of the table.
+
+Used when performing `SELECT` from a distributed table that points to replicated tables.
+
+By default, 1 (enabled).
+
+## force_index_by_date {#settings-force_index_by_date}
+
+Disables query execution if the index can’t be used by date.
+
+Works with tables in the MergeTree family.
+
+If `force_index_by_date=1`, ClickHouse checks whether the query has a date key condition that can be used for restricting data ranges. If there is no suitable condition, it throws an exception. However, it does not check whether the condition reduces the amount of data to read. For example, the condition `Date != ' 2000-01-01 '` is acceptable even when it matches all the data in the table (i.e., running the query requires a full scan). For more information about ranges of data in MergeTree tables, see [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md).
+
+## force_primary_key {#force-primary-key}
+
+Disables query execution if indexing by the primary key is not possible.
+
+Works with tables in the MergeTree family.
+
+If `force_primary_key=1`, ClickHouse checks to see if the query has a primary key condition that can be used for restricting data ranges. If there is no suitable condition, it throws an exception. However, it does not check whether the condition reduces the amount of data to read. For more information about data ranges in MergeTree tables, see [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md).
+
+## use_skip_indexes {#settings-use_skip_indexes}
+
+Use data skipping indexes during query execution.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1.
+
+## force_data_skipping_indices {#settings-force_data_skipping_indices}
+
+Disables query execution if passed data skipping indices wasn't used.
+
+Consider the following example:
+
+```sql
+CREATE TABLE data
+(
+    key Int,
+    d1 Int,
+    d1_null Nullable(Int),
+    INDEX d1_idx d1 TYPE minmax GRANULARITY 1,
+    INDEX d1_null_idx assumeNotNull(d1_null) TYPE minmax GRANULARITY 1
+)
+Engine=MergeTree()
+ORDER BY key;
+
+SELECT * FROM data_01515;
+SELECT * FROM data_01515 SETTINGS force_data_skipping_indices=''; -- query will produce CANNOT_PARSE_TEXT error.
+SELECT * FROM data_01515 SETTINGS force_data_skipping_indices='d1_idx'; -- query will produce INDEX_NOT_USED error.
+SELECT * FROM data_01515 WHERE d1 = 0 SETTINGS force_data_skipping_indices='d1_idx'; -- Ok.
+SELECT * FROM data_01515 WHERE d1 = 0 SETTINGS force_data_skipping_indices='`d1_idx`'; -- Ok (example of full featured parser).
+SELECT * FROM data_01515 WHERE d1 = 0 SETTINGS force_data_skipping_indices='`d1_idx`, d1_null_idx'; -- query will produce INDEX_NOT_USED error, since d1_null_idx is not used.
+SELECT * FROM data_01515 WHERE d1 = 0 AND assumeNotNull(d1_null) = 0 SETTINGS force_data_skipping_indices='`d1_idx`, d1_null_idx'; -- Ok.
+```
+
+Works with tables in the MergeTree family.
+
+## format_schema {#format-schema}
+
+This parameter is useful when you are using formats that require a schema definition, such as [Cap’n Proto](https://capnproto.org/) or [Protobuf](https://developers.google.com/protocol-buffers/). The value depends on the format.
+
+## fsync_metadata {#fsync-metadata}
+
+Enables or disables [fsync](http://pubs.opengroup.org/onlinepubs/9699919799/functions/fsync.html) when writing `.sql` files. Enabled by default.
+
+It makes sense to disable it if the server has millions of tiny tables that are constantly being created and destroyed.
+
+## function_range_max_elements_in_block {#settings-function_range_max_elements_in_block}
+
+Sets the safety threshold for data volume generated by function [range](../../sql-reference/functions/array-functions.md#range). Defines the maximum number of values generated by function per block of data (sum of array sizes for every row in a block).
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `500,000,000`.
+
+**See Also**
+
+-   [max_block_size](#setting-max_block_size)
+-   [min_insert_block_size_rows](#min-insert-block-size-rows)
+
+## enable_http_compression {#settings-enable_http_compression}
+
+Enables or disables data compression in the response to an HTTP request.
+
+For more information, read the [HTTP interface description](../../interfaces/http.md).
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+## http_zlib_compression_level {#settings-http_zlib_compression_level}
+
+Sets the level of data compression in the response to an HTTP request if [enable_http_compression = 1](#settings-enable_http_compression).
+
+Possible values: Numbers from 1 to 9.
+
+Default value: 3.
+
+## http_native_compression_disable_checksumming_on_decompress {#settings-http_native_compression_disable_checksumming_on_decompress}
+
+Enables or disables checksum verification when decompressing the HTTP POST data from the client. Used only for ClickHouse native compression format (not used with `gzip` or `deflate`).
+
+For more information, read the [HTTP interface description](../../interfaces/http.md).
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+## http_max_uri_size {#http-max-uri-size}
+
+Sets the maximum URI length of an HTTP request.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: 1048576.
+
+## table_function_remote_max_addresses {#table_function_remote_max_addresses}
+
+Sets the maximum number of addresses generated from patterns for the [remote](../../sql-reference/table-functions/remote.md) function.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `1000`.
+
+##  glob_expansion_max_elements  {#glob_expansion_max_elements }
+
+Sets the maximum number of addresses generated from patterns for external storages and table functions (like [url](../../sql-reference/table-functions/url.md)) except the `remote` function.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `1000`.
+
+## send_progress_in_http_headers {#settings-send_progress_in_http_headers}
+
+Enables or disables `X-ClickHouse-Progress` HTTP response headers in `clickhouse-server` responses.
+
+For more information, read the [HTTP interface description](../../interfaces/http.md).
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+## max_http_get_redirects {#setting-max_http_get_redirects}
+
+Limits the maximum number of HTTP GET redirect hops for [URL](../../engines/table-engines/special/url.md)-engine tables. The setting applies to both types of tables: those created by the [CREATE TABLE](../../sql-reference/statements/create/table.md) query and by the [url](../../sql-reference/table-functions/url.md) table function.
+
+Possible values:
+
+-   Any positive integer number of hops.
+-   0 — No hops allowed.
+
+Default value: 0.
+
+## input_format_allow_errors_num {#settings-input_format_allow_errors_num}
+
+Sets the maximum number of acceptable errors when reading from text formats (CSV, TSV, etc.).
+
+The default value is 0.
+
+Always pair it with `input_format_allow_errors_ratio`.
+
+If an error occurred while reading rows but the error counter is still less than `input_format_allow_errors_num`, ClickHouse ignores the row and moves on to the next one.
+
+If both `input_format_allow_errors_num` and `input_format_allow_errors_ratio` are exceeded, ClickHouse throws an exception.
+
+## input_format_allow_errors_ratio {#settings-input_format_allow_errors_ratio}
+
+Sets the maximum percentage of errors allowed when reading from text formats (CSV, TSV, etc.).
+The percentage of errors is set as a floating-point number between 0 and 1.
+
+The default value is 0.
+
+Always pair it with `input_format_allow_errors_num`.
+
+If an error occurred while reading rows but the error counter is still less than `input_format_allow_errors_ratio`, ClickHouse ignores the row and moves on to the next one.
+
+If both `input_format_allow_errors_num` and `input_format_allow_errors_ratio` are exceeded, ClickHouse throws an exception.
+
+## input_format_parquet_import_nested {#input_format_parquet_import_nested}
+
+Enables or disables the ability to insert the data into [Nested](../../sql-reference/data-types/nested-data-structures/nested.md) columns as an array of structs in [Parquet](../../interfaces/formats.md#data-format-parquet) input format.
+
+Possible values:
+
+-   0 — Data can not be inserted into `Nested` columns as an array of structs.
+-   1 — Data can be inserted into `Nested` columns as an array of structs.
+
+Default value: `0`.
+
+## input_format_arrow_import_nested {#input_format_arrow_import_nested}
+
+Enables or disables the ability to insert the data into [Nested](../../sql-reference/data-types/nested-data-structures/nested.md) columns as an array of structs in [Arrow](../../interfaces/formats.md#data_types-matching-arrow) input format.
+
+Possible values:
+
+-   0 — Data can not be inserted into `Nested` columns as an array of structs.
+-   1 — Data can be inserted into `Nested` columns as an array of structs.
+
+Default value: `0`.
+
+## input_format_orc_import_nested {#input_format_orc_import_nested}
+
+Enables or disables the ability to insert the data into [Nested](../../sql-reference/data-types/nested-data-structures/nested.md) columns as an array of structs in [ORC](../../interfaces/formats.md#data-format-orc) input format.
+
+Possible values:
+
+-   0 — Data can not be inserted into `Nested` columns as an array of structs.
+-   1 — Data can be inserted into `Nested` columns as an array of structs.
+
+Default value: `0`.
+
+## input_format_values_interpret_expressions {#settings-input_format_values_interpret_expressions}
+
+Enables or disables the full SQL parser if the fast stream parser can’t parse the data. This setting is used only for the [Values](../../interfaces/formats.md#data-format-values) format at the data insertion. For more information about syntax parsing, see the [Syntax](../../sql-reference/syntax.md) section.
+
+Possible values:
+
+-   0 — Disabled.
+
+    In this case, you must provide formatted data. See the [Formats](../../interfaces/formats.md) section.
+
+-   1 — Enabled.
+
+    In this case, you can use an SQL expression as a value, but data insertion is much slower this way. If you insert only formatted data, then ClickHouse behaves as if the setting value is 0.
+
+Default value: 1.
+
+Example of Use
+
+Insert the [DateTime](../../sql-reference/data-types/datetime.md) type value with the different settings.
+
+``` sql
+SET input_format_values_interpret_expressions = 0;
+INSERT INTO datetime_t VALUES (now())
+```
+
+``` text
+Exception on client:
+Code: 27. DB::Exception: Cannot parse input: expected ) before: now()): (at row 1)
+```
+
+``` sql
+SET input_format_values_interpret_expressions = 1;
+INSERT INTO datetime_t VALUES (now())
+```
+
+``` text
+Ok.
+```
+
+The last query is equivalent to the following:
+
+``` sql
+SET input_format_values_interpret_expressions = 0;
+INSERT INTO datetime_t SELECT now()
+```
+
+``` text
+Ok.
+```
+
+## input_format_values_deduce_templates_of_expressions {#settings-input_format_values_deduce_templates_of_expressions}
+
+Enables or disables template deduction for SQL expressions in [Values](../../interfaces/formats.md#data-format-values) format. It allows parsing and interpreting expressions in `Values` much faster if expressions in consecutive rows have the same structure. ClickHouse tries to deduce the template of an expression, parse the following rows using this template and evaluate the expression on a batch of successfully parsed rows.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1.
+
+For the following query:
+
+``` sql
+INSERT INTO test VALUES (lower('Hello')), (lower('world')), (lower('INSERT')), (upper('Values')), ...
+```
+
+-   If `input_format_values_interpret_expressions=1` and `format_values_deduce_templates_of_expressions=0`, expressions are interpreted separately for each row (this is very slow for large number of rows).
+-   If `input_format_values_interpret_expressions=0` and `format_values_deduce_templates_of_expressions=1`, expressions in the first, second and third rows are parsed using template `lower(String)` and interpreted together, expression in the forth row is parsed with another template (`upper(String)`).
+-   If `input_format_values_interpret_expressions=1` and `format_values_deduce_templates_of_expressions=1`, the same as in previous case, but also allows fallback to interpreting expressions separately if it’s not possible to deduce template.
+
+## input_format_values_accurate_types_of_literals {#settings-input-format-values-accurate-types-of-literals}
+
+This setting is used only when `input_format_values_deduce_templates_of_expressions = 1`. Expressions for some column may have the same structure, but contain numeric literals of different types, e.g.
+
+``` sql
+(..., abs(0), ...),             -- UInt64 literal
+(..., abs(3.141592654), ...),   -- Float64 literal
+(..., abs(-1), ...),            -- Int64 literal
+```
+
+Possible values:
+
+-   0 — Disabled.
+
+    In this case, ClickHouse may use a more general type for some literals (e.g., `Float64` or `Int64` instead of `UInt64` for `42`), but it may cause overflow and precision issues.
+
+-   1 — Enabled.
+
+    In this case, ClickHouse checks the actual type of literal and uses an expression template of the corresponding type. In some cases, it may significantly slow down expression evaluation in `Values`.
+
+Default value: 1.
+
+## input_format_defaults_for_omitted_fields {#session_settings-input_format_defaults_for_omitted_fields}
+
+When performing `INSERT` queries, replace omitted input column values with default values of the respective columns. This option only applies to [JSONEachRow](../../interfaces/formats.md#jsoneachrow), [CSV](../../interfaces/formats.md#csv), [TabSeparated](../../interfaces/formats.md#tabseparated) formats and formats with `WithNames`/`WithNamesAndTypes` suffixes.
+
+:::note
+When this option is enabled, extended table metadata are sent from server to client. It consumes additional computing resources on the server and can reduce performance.
+:::
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1.
+
+## input_format_tsv_empty_as_default {#settings-input-format-tsv-empty-as-default}
+
+When enabled, replace empty input fields in TSV with default values. For complex default expressions `input_format_defaults_for_omitted_fields` must be enabled too.
+
+Disabled by default.
+
+## input_format_csv_empty_as_default {#settings-input-format-csv-empty-as-default}
+
+When enabled, replace empty input fields in CSV with default values. For complex default expressions `input_format_defaults_for_omitted_fields` must be enabled too.
+
+Enabled by default.
+
+## input_format_tsv_enum_as_number {#settings-input_format_tsv_enum_as_number}
+
+When enabled, always treat enum values as enum ids for TSV input format. It's recommended to enable this setting if data contains only enum ids to optimize enum parsing.
+
+Possible values:
+
+-   0 — Enum values are parsed as values or as enum IDs.
+-   1 — Enum values are parsed only as enum IDs.
+
+Default value: 0.
+
+**Example**
+
+Consider the table:
+
+```sql
+CREATE TABLE table_with_enum_column_for_tsv_insert (Id Int32,Value Enum('first' = 1, 'second' = 2)) ENGINE=Memory();
+```
+
+When the `input_format_tsv_enum_as_number` setting is enabled:
+
+Query:
+
+```sql
+SET input_format_tsv_enum_as_number = 1;
+INSERT INTO table_with_enum_column_for_tsv_insert FORMAT TSV 102	2;
+SELECT * FROM table_with_enum_column_for_tsv_insert;
+```
+
+Result:
+
+```text
+┌──Id─┬─Value──┐
+│ 102 │ second │
+└─────┴────────┘
+```
+
+Query:
+
+```sql
+SET input_format_tsv_enum_as_number = 1;
+INSERT INTO table_with_enum_column_for_tsv_insert FORMAT TSV 103	'first';
+```
+
+throws an exception.
+
+When the `input_format_tsv_enum_as_number` setting is disabled:
+
+Query:
+
+```sql
+SET input_format_tsv_enum_as_number = 0;
+INSERT INTO table_with_enum_column_for_tsv_insert FORMAT TSV 102	2;
+INSERT INTO table_with_enum_column_for_tsv_insert FORMAT TSV 103	'first';
+SELECT * FROM table_with_enum_column_for_tsv_insert;
+```
+
+Result:
+
+```text
+┌──Id─┬─Value──┐
+│ 102 │ second │
+└─────┴────────┘
+┌──Id─┬─Value──┐
+│ 103 │ first  │
+└─────┴────────┘
+```
+
+## input_format_null_as_default {#settings-input-format-null-as-default}
+
+Enables or disables the initialization of [NULL](../../sql-reference/syntax.md#null-literal) fields with [default values](../../sql-reference/statements/create/table.md#create-default-values), if data type of these fields is not [nullable](../../sql-reference/data-types/nullable.md#data_type-nullable).
+If column type is not nullable and this setting is disabled, then inserting `NULL` causes an exception. If column type is nullable, then `NULL` values are inserted as is, regardless of this setting.
+
+This setting is applicable to [INSERT ... VALUES](../../sql-reference/statements/insert-into.md) queries for text input formats.
+
+Possible values:
+
+-   0 — Inserting `NULL` into a not nullable column causes an exception.
+-   1 — `NULL` fields are initialized with default column values.
+
+Default value: `1`.
+
+## insert_null_as_default {#insert_null_as_default}
+
+Enables or disables the insertion of [default values](../../sql-reference/statements/create/table.md#create-default-values) instead of [NULL](../../sql-reference/syntax.md#null-literal) into columns with not [nullable](../../sql-reference/data-types/nullable.md#data_type-nullable) data type.
+If column type is not nullable and this setting is disabled, then inserting `NULL` causes an exception. If column type is nullable, then `NULL` values are inserted as is, regardless of this setting.
+
+This setting is applicable to [INSERT ... SELECT](../../sql-reference/statements/insert-into.md#insert_query_insert-select) queries. Note that `SELECT` subqueries may be concatenated with `UNION ALL` clause.
+
+Possible values:
+
+-   0 — Inserting `NULL` into a not nullable column causes an exception.
+-   1 — Default column value is inserted instead of `NULL`.
+
+Default value: `1`.
+
+## input_format_skip_unknown_fields {#settings-input-format-skip-unknown-fields}
+
+Enables or disables skipping insertion of extra data.
+
+When writing data, ClickHouse throws an exception if input data contain columns that do not exist in the target table. If skipping is enabled, ClickHouse does not insert extra data and does not throw an exception.
+
+Supported formats:
+
+-   [JSONEachRow](../../interfaces/formats.md#jsoneachrow)
+-   [CSVWithNames](../../interfaces/formats.md#csvwithnames)
+-   [TabSeparatedWithNames](../../interfaces/formats.md#tabseparatedwithnames)
+-   [TSKV](../../interfaces/formats.md#tskv)
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+## input_format_import_nested_json {#settings-input_format_import_nested_json}
+
+Enables or disables the insertion of JSON data with nested objects.
+
+Supported formats:
+
+-   [JSONEachRow](../../interfaces/formats.md#jsoneachrow)
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+See also:
+
+-   [Usage of Nested Structures](../../interfaces/formats.md#jsoneachrow-nested) with the `JSONEachRow` format.
+
+## input_format_with_names_use_header {#settings-input-format-with-names-use-header}
+
+Enables or disables checking the column order when inserting data.
+
+To improve insert performance, we recommend disabling this check if you are sure that the column order of the input data is the same as in the target table.
+
+Supported formats:
+
+- [CSVWithNames](../../interfaces/formats.md#csvwithnames)
+- [CSVWithNames](../../interfaces/formats.md#csvwithnamesandtypes)
+- [TabSeparatedWithNames](../../interfaces/formats.md#tabseparatedwithnames)
+- [TabSeparatedWithNamesAndTypes](../../interfaces/formats.md#tabseparatedwithnamesandtypes)
+- [JSONCompactEachRowWithNames](../../interfaces/formats.md#jsoncompacteachrowwithnames)
+- [JSONCompactEachRowWithNamesAndTypes](../../interfaces/formats.md#jsoncompacteachrowwithnamesandtypes)
+- [JSONCompactStringsEachRowWithNames](../../interfaces/formats.md#jsoncompactstringseachrowwithnames)
+- [JSONCompactStringsEachRowWithNamesAndTypes](../../interfaces/formats.md#jsoncompactstringseachrowwithnamesandtypes)
+- [RowBinaryWithNames](../../interfaces/formats.md#rowbinarywithnames-rowbinarywithnames)
+- [RowBinaryWithNamesAndTypes](../../interfaces/formats.md#rowbinarywithnamesandtypes-rowbinarywithnamesandtypes)
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1.
+
+## input_format_with_types_use_header {#settings-input-format-with-types-use-header}
+
+Controls whether format parser should check if data types from the input data match data types from the target table.
+
+Supported formats:
+
+- [CSVWithNames](../../interfaces/formats.md#csvwithnames)
+- [CSVWithNames](../../interfaces/formats.md#csvwithnamesandtypes)
+- [TabSeparatedWithNames](../../interfaces/formats.md#tabseparatedwithnames)
+- [TabSeparatedWithNamesAndTypes](../../interfaces/formats.md#tabseparatedwithnamesandtypes)
+- [JSONCompactEachRowWithNames](../../interfaces/formats.md#jsoncompacteachrowwithnames)
+- [JSONCompactEachRowWithNamesAndTypes](../../interfaces/formats.md#jsoncompacteachrowwithnamesandtypes)
+- [JSONCompactStringsEachRowWithNames](../../interfaces/formats.md#jsoncompactstringseachrowwithnames)
+- [JSONCompactStringsEachRowWithNamesAndTypes](../../interfaces/formats.md#jsoncompactstringseachrowwithnamesandtypes)
+- [RowBinaryWithNames](../../interfaces/formats.md#rowbinarywithnames-rowbinarywithnames)
+- [RowBinaryWithNamesAndTypes](../../interfaces/formats.md#rowbinarywithnamesandtypes-rowbinarywithnamesandtypes)
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1.
+
+## date_time_input_format {#settings-date_time_input_format}
+
+Allows choosing a parser of the text representation of date and time.
+
+The setting does not apply to [date and time functions](../../sql-reference/functions/date-time-functions.md).
+
+Possible values:
+
+-   `'best_effort'` — Enables extended parsing.
+
+    ClickHouse can parse the basic `YYYY-MM-DD HH:MM:SS` format and all [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) date and time formats. For example, `'2018-06-08T01:02:03.000Z'`.
+
+-   `'basic'` — Use basic parser.
+
+    ClickHouse can parse only the basic `YYYY-MM-DD HH:MM:SS` or `YYYY-MM-DD` format. For example, `2019-08-20 10:18:56` or `2019-08-20`.
+
+Default value: `'basic'`.
+
+See also:
+
+-   [DateTime data type.](../../sql-reference/data-types/datetime.md)
+-   [Functions for working with dates and times.](../../sql-reference/functions/date-time-functions.md)
+
+## date_time_output_format {#settings-date_time_output_format}
+
+Allows choosing different output formats of the text representation of date and time.
+
+Possible values:
+
+-   `simple` - Simple output format.
+
+    ClickHouse output date and time `YYYY-MM-DD hh:mm:ss` format. For example, `2019-08-20 10:18:56`. The calculation is performed according to the data type's time zone (if present) or server time zone.
+
+-   `iso` - ISO output format.
+
+    ClickHouse output date and time in [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) `YYYY-MM-DDThh:mm:ssZ` format. For example, `2019-08-20T10:18:56Z`. Note that output is in UTC (`Z` means UTC).
+
+-   `unix_timestamp` - Unix timestamp output format.
+
+    ClickHouse output date and time in [Unix timestamp](https://en.wikipedia.org/wiki/Unix_time) format. For example `1566285536`.
+
+Default value: `simple`.
+
+See also:
+
+-   [DateTime data type.](../../sql-reference/data-types/datetime.md)
+-   [Functions for working with dates and times.](../../sql-reference/functions/date-time-functions.md)
+
+## join_default_strictness {#settings-join_default_strictness}
+
+Sets default strictness for [JOIN clauses](../../sql-reference/statements/select/join.md#select-join).
+
+Possible values:
+
+-   `ALL` — If the right table has several matching rows, ClickHouse creates a [Cartesian product](https://en.wikipedia.org/wiki/Cartesian_product) from matching rows. This is the normal `JOIN` behaviour from standard SQL.
+-   `ANY` — If the right table has several matching rows, only the first one found is joined. If the right table has only one matching row, the results of `ANY` and `ALL` are the same.
+-   `ASOF` — For joining sequences with an uncertain match.
+-   `Empty string` — If `ALL` or `ANY` is not specified in the query, ClickHouse throws an exception.
+
+Default value: `ALL`.
+
+## join_algorithm {#settings-join_algorithm}
+
+Specifies [JOIN](../../sql-reference/statements/select/join.md) algorithm.
+
+Possible values:
+
+- `hash` — [Hash join algorithm](https://en.wikipedia.org/wiki/Hash_join) is used.
+- `partial_merge` — [Sort-merge algorithm](https://en.wikipedia.org/wiki/Sort-merge_join) is used.
+- `prefer_partial_merge` — ClickHouse always tries to use `merge` join if possible.
+- `auto` — ClickHouse tries to change `hash` join to `merge` join on the fly to avoid out of memory.
+
+Default value: `hash`.
+
+When using `hash` algorithm the right part of `JOIN` is uploaded into RAM.
+
+When using `partial_merge` algorithm ClickHouse sorts the data and dumps it to the disk. The `merge` algorithm in ClickHouse differs a bit from the classic realization. First ClickHouse sorts the right table by [join key](../../sql-reference/statements/select/join.md#select-join) in blocks and creates min-max index for sorted blocks. Then it sorts parts of left table by `join key` and joins them over right table. The min-max index is also used to skip unneeded right table blocks.
+
+## join_any_take_last_row {#settings-join_any_take_last_row}
+
+Changes behaviour of join operations with `ANY` strictness.
+
+:::warning
+This setting applies only for `JOIN` operations with [Join](../../engines/table-engines/special/join.md) engine tables.
+:::
+
+Possible values:
+
+-   0 — If the right table has more than one matching row, only the first one found is joined.
+-   1 — If the right table has more than one matching row, only the last one found is joined.
+
+Default value: 0.
+
+See also:
+
+-   [JOIN clause](../../sql-reference/statements/select/join.md#select-join)
+-   [Join table engine](../../engines/table-engines/special/join.md)
+-   [join_default_strictness](#settings-join_default_strictness)
+
+## join_use_nulls {#join_use_nulls}
+
+Sets the type of [JOIN](../../sql-reference/statements/select/join.md) behaviour. When merging tables, empty cells may appear. ClickHouse fills them differently based on this setting.
+
+Possible values:
+
+-   0 — The empty cells are filled with the default value of the corresponding field type.
+-   1 — `JOIN` behaves the same way as in standard SQL. The type of the corresponding field is converted to [Nullable](../../sql-reference/data-types/nullable.md#data_type-nullable), and empty cells are filled with [NULL](../../sql-reference/syntax.md).
+
+Default value: 0.
+
+## partial_merge_join_optimizations {#partial_merge_join_optimizations}
+
+Disables optimizations in partial merge join algorithm for [JOIN](../../sql-reference/statements/select/join.md) queries.
+
+By default, this setting enables improvements that could lead to wrong results. If you see suspicious results in your queries, disable optimizations by this setting. Optimizations can be different in different versions of the ClickHouse server.
+
+Possible values:
+
+-   0 — Optimizations disabled.
+-   1 — Optimizations enabled.
+
+Default value: 1.
+
+## partial_merge_join_rows_in_right_blocks {#partial_merge_join_rows_in_right_blocks}
+
+Limits sizes of right-hand join data blocks in partial merge join algorithm for [JOIN](../../sql-reference/statements/select/join.md) queries.
+
+ClickHouse server:
+
+1.  Splits right-hand join data into blocks with up to the specified number of rows.
+2.  Indexes each block with its minimum and maximum values.
+3.  Unloads prepared blocks to disk if it is possible.
+
+Possible values:
+
+-   Any positive integer. Recommended range of values: \[1000, 100000\].
+
+Default value: 65536.
+
+## join_on_disk_max_files_to_merge {#join_on_disk_max_files_to_merge}
+
+Limits the number of files allowed for parallel sorting in MergeJoin operations when they are executed on disk.
+
+The bigger the value of the setting, the more RAM used and the less disk I/O needed.
+
+Possible values:
+
+-   Any positive integer, starting from 2.
+
+Default value: 64.
+
+## any_join_distinct_right_table_keys {#any_join_distinct_right_table_keys}
+
+Enables legacy ClickHouse server behaviour in `ANY INNER|LEFT JOIN` operations.
+
+:::warning
+Use this setting only for backward compatibility if your use cases depend on legacy `JOIN` behaviour.
+:::
+
+When the legacy behaviour enabled:
+
+-   Results of `t1 ANY LEFT JOIN t2` and `t2 ANY RIGHT JOIN t1` operations are not equal because ClickHouse uses the logic with many-to-one left-to-right table keys mapping.
+-   Results of `ANY INNER JOIN` operations contain all rows from the left table like the `SEMI LEFT JOIN` operations do.
+
+When the legacy behaviour disabled:
+
+-   Results of `t1 ANY LEFT JOIN t2` and `t2 ANY RIGHT JOIN t1` operations are equal because ClickHouse uses the logic which provides one-to-many keys mapping in `ANY RIGHT JOIN` operations.
+-   Results of `ANY INNER JOIN` operations contain one row per key from both the left and right tables.
+
+Possible values:
+
+-   0 — Legacy behaviour is disabled.
+-   1 — Legacy behaviour is enabled.
+
+Default value: 0.
+
+See also:
+
+-   [JOIN strictness](../../sql-reference/statements/select/join.md#join-settings)
+
+## temporary_files_codec {#temporary_files_codec}
+
+Sets compression codec for temporary files used in sorting and joining operations on disk.
+
+Possible values:
+
+-   LZ4 — [LZ4](https://en.wikipedia.org/wiki/LZ4_(compression_algorithm)) compression is applied.
+-   NONE — No compression is applied.
+
+Default value: LZ4.
+
+## max_block_size {#setting-max_block_size}
+
+In ClickHouse, data is processed by blocks (sets of column parts). The internal processing cycles for a single block are efficient enough, but there are noticeable expenditures on each block. The `max_block_size` setting is a recommendation for what size of the block (in a count of rows) to load from tables. The block size shouldn’t be too small, so that the expenditures on each block are still noticeable, but not too large so that the query with LIMIT that is completed after the first block is processed quickly. The goal is to avoid consuming too much memory when extracting a large number of columns in multiple threads and to preserve at least some cache locality.
+
+Default value: 65,536.
+
+Blocks the size of `max_block_size` are not always loaded from the table. If it is obvious that less data needs to be retrieved, a smaller block is processed.
+
+## preferred_block_size_bytes {#preferred-block-size-bytes}
+
+Used for the same purpose as `max_block_size`, but it sets the recommended block size in bytes by adapting it to the number of rows in the block.
+However, the block size cannot be more than `max_block_size` rows.
+By default: 1,000,000. It only works when reading from MergeTree engines.
+
+## merge_tree_min_rows_for_concurrent_read {#setting-merge-tree-min-rows-for-concurrent-read}
+
+If the number of rows to be read from a file of a [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) table exceeds `merge_tree_min_rows_for_concurrent_read` then ClickHouse tries to perform a concurrent reading from this file on several threads.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `163840`.
+
+## merge_tree_min_rows_for_concurrent_read_for_remote_filesystem {#merge-tree-min-rows-for-concurrent-read-for-remote-filesystem}
+
+The minimum number of lines to read from one file before [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) engine can parallelize reading, when reading from remote filesystem.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `163840`.
+
+## merge_tree_min_bytes_for_concurrent_read {#setting-merge-tree-min-bytes-for-concurrent-read}
+
+If the number of bytes to read from one file of a [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md)-engine table exceeds `merge_tree_min_bytes_for_concurrent_read`, then ClickHouse tries to concurrently read from this file in several threads.
+
+Possible value:
+
+-   Positive integer.
+
+Default value: `251658240`.
+
+## merge_tree_min_bytes_for_concurrent_read_for_remote_filesystem {#merge-tree-min-bytes-for-concurrent-read-for-remote-filesystem}
+
+The minimum number of bytes to read from one file before [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) engine can parallelize reading, when reading from remote filesystem.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `251658240`.
+
+## merge_tree_min_rows_for_seek {#setting-merge-tree-min-rows-for-seek}
+
+If the distance between two data blocks to be read in one file is less than `merge_tree_min_rows_for_seek` rows, then ClickHouse does not seek through the file but reads the data sequentially.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 0.
+
+## merge_tree_min_bytes_for_seek {#setting-merge-tree-min-bytes-for-seek}
+
+If the distance between two data blocks to be read in one file is less than `merge_tree_min_bytes_for_seek` bytes, then ClickHouse sequentially reads a range of file that contains both blocks, thus avoiding extra seek.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 0.
+
+## merge_tree_coarse_index_granularity {#setting-merge-tree-coarse-index-granularity}
+
+When searching for data, ClickHouse checks the data marks in the index file. If ClickHouse finds that required keys are in some range, it divides this range into `merge_tree_coarse_index_granularity` subranges and searches the required keys there recursively.
+
+Possible values:
+
+-   Any positive even integer.
+
+Default value: 8.
+
+## merge_tree_max_rows_to_use_cache {#setting-merge-tree-max-rows-to-use-cache}
+
+If ClickHouse should read more than `merge_tree_max_rows_to_use_cache` rows in one query, it does not use the cache of uncompressed blocks.
+
+The cache of uncompressed blocks stores data extracted for queries. ClickHouse uses this cache to speed up responses to repeated small queries. This setting protects the cache from trashing by queries that read a large amount of data. The [uncompressed_cache_size](../../operations/server-configuration-parameters/settings.md#server-settings-uncompressed_cache_size) server setting defines the size of the cache of uncompressed blocks.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 128 ✕ 8192.
+
+## merge_tree_max_bytes_to_use_cache {#setting-merge-tree-max-bytes-to-use-cache}
+
+If ClickHouse should read more than `merge_tree_max_bytes_to_use_cache` bytes in one query, it does not use the cache of uncompressed blocks.
+
+The cache of uncompressed blocks stores data extracted for queries. ClickHouse uses this cache to speed up responses to repeated small queries. This setting protects the cache from trashing by queries that read a large amount of data. The [uncompressed_cache_size](../../operations/server-configuration-parameters/settings.md#server-settings-uncompressed_cache_size) server setting defines the size of the cache of uncompressed blocks.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 2013265920.
+
+## min_bytes_to_use_direct_io {#settings-min-bytes-to-use-direct-io}
+
+The minimum data volume required for using direct I/O access to the storage disk.
+
+ClickHouse uses this setting when reading data from tables. If the total storage volume of all the data to be read exceeds `min_bytes_to_use_direct_io` bytes, then ClickHouse reads the data from the storage disk with the `O_DIRECT` option.
+
+Possible values:
+
+-   0 — Direct I/O is disabled.
+-   Positive integer.
+
+Default value: 0.
+
+## network_compression_method {#network_compression_method}
+
+Sets the method of data compression that is used for communication between servers and between server and [clickhouse-client](../../interfaces/cli.md).
+
+Possible values:
+
+-   `LZ4` — sets LZ4 compression method.
+-   `ZSTD` — sets ZSTD compression method.
+
+Default value: `LZ4`.
+
+**See Also**
+
+-   [network_zstd_compression_level](#network_zstd_compression_level)
+
+## network_zstd_compression_level {#network_zstd_compression_level}
+
+Adjusts the level of ZSTD compression. Used only when [network_compression_method](#network_compression_method) is set to `ZSTD`.
+
+Possible values:
+
+-   Positive integer from 1 to 15.
+
+Default value: `1`.
+
+## log_queries {#settings-log-queries}
+
+Setting up query logging.
+
+Queries sent to ClickHouse with this setup are logged according to the rules in the [query_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-query-log) server configuration parameter.
+
+Example:
+
+``` text
+log_queries=1
+```
+
+## log_queries_min_query_duration_ms {#settings-log-queries-min-query-duration-ms}
+
+If enabled (non-zero), queries faster then the value of this setting will not be logged (you can think about this as a `long_query_time` for [MySQL Slow Query Log](https://dev.mysql.com/doc/refman/5.7/en/slow-query-log.html)), and this basically means that you will not find them in the following tables:
+
+- `system.query_log`
+- `system.query_thread_log`
+
+Only the queries with the following type will get to the log:
+
+- `QUERY_FINISH`
+- `EXCEPTION_WHILE_PROCESSING`
+
+-   Type: milliseconds
+-   Default value: 0 (any query)
+
+## log_queries_min_type {#settings-log-queries-min-type}
+
+`query_log` minimal type to log.
+
+Possible values:
+- `QUERY_START` (`=1`)
+- `QUERY_FINISH` (`=2`)
+- `EXCEPTION_BEFORE_START` (`=3`)
+- `EXCEPTION_WHILE_PROCESSING` (`=4`)
+
+Default value: `QUERY_START`.
+
+Can be used to limit which entities will go to `query_log`, say you are interested only in errors, then you can use `EXCEPTION_WHILE_PROCESSING`:
+
+``` text
+log_queries_min_type='EXCEPTION_WHILE_PROCESSING'
+```
+
+## log_query_threads {#settings-log-query-threads}
+
+Setting up query threads logging.
+
+Query threads log into [system.query_thread_log](../../operations/system-tables/query_thread_log.md) table. This setting have effect only when [log_queries](#settings-log-queries) is true. Queries’ threads run by ClickHouse with this setup are logged according to the rules in the [query_thread_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-query_thread_log) server configuration parameter.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: `1`.
+
+**Example**
+
+``` text
+log_query_threads=1
+```
+
+## log_query_views {#settings-log-query-views}
+
+Setting up query views logging.
+
+When a query run by ClickHouse with this setup on has associated views (materialized or live views), they are logged in the [query_views_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-query_views_log) server configuration parameter.
+
+Example:
+
+``` text
+log_query_views=1
+```
+
+## log_formatted_queries {#settings-log-formatted-queries}
+
+Allows to log formatted queries to the [system.query_log](../../operations/system-tables/query_log.md) system table.
+
+Possible values:
+
+-   0 — Formatted queries are not logged in the system table.
+-   1 — Formatted queries are logged in the system table.
+
+Default value: `0`.
+
+## log_comment {#settings-log-comment}
+
+Specifies the value for the `log_comment` field of the [system.query_log](../system-tables/query_log.md) table and comment text for the server log.
+
+It can be used to improve the readability of server logs. Additionally, it helps to select queries related to the test from the `system.query_log` after running [clickhouse-test](../../development/tests.md).
+
+Possible values:
+
+-   Any string no longer than [max_query_size](#settings-max_query_size). If length is exceeded, the server throws an exception.
+
+Default value: empty string.
+
+**Example**
+
+Query:
+
+``` sql
+SET log_comment = 'log_comment test', log_queries = 1;
+SELECT 1;
+SYSTEM FLUSH LOGS;
+SELECT type, query FROM system.query_log WHERE log_comment = 'log_comment test' AND event_date >= yesterday() ORDER BY event_time DESC LIMIT 2;
+```
+
+Result:
+
+``` text
+┌─type────────┬─query─────┐
+│ QueryStart  │ SELECT 1; │
+│ QueryFinish │ SELECT 1; │
+└─────────────┴───────────┘
+```
+
+## max_insert_block_size {#settings-max_insert_block_size}
+
+The size of blocks (in a count of rows) to form for insertion into a table.
+This setting only applies in cases when the server forms the blocks.
+For example, for an INSERT via the HTTP interface, the server parses the data format and forms blocks of the specified size.
+But when using clickhouse-client, the client parses the data itself, and the ‘max_insert_block_size’ setting on the server does not affect the size of the inserted blocks.
+The setting also does not have a purpose when using INSERT SELECT, since data is inserted using the same blocks that are formed after SELECT.
+
+Default value: 1,048,576.
+
+The default is slightly more than `max_block_size`. The reason for this is because certain table engines (`*MergeTree`) form a data part on the disk for each inserted block, which is a fairly large entity. Similarly, `*MergeTree` tables sort data during insertion, and a large enough block size allow sorting more data in RAM.
+
+## min_insert_block_size_rows {#min-insert-block-size-rows}
+
+Sets the minimum number of rows in the block which can be inserted into a table by an `INSERT` query. Smaller-sized blocks are squashed into bigger ones.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Squashing disabled.
+
+Default value: 1048576.
+
+## min_insert_block_size_bytes {#min-insert-block-size-bytes}
+
+Sets the minimum number of bytes in the block which can be inserted into a table by an `INSERT` query. Smaller-sized blocks are squashed into bigger ones.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Squashing disabled.
+
+Default value: 268435456.
+
+## max_replica_delay_for_distributed_queries {#settings-max_replica_delay_for_distributed_queries}
+
+Disables lagging replicas for distributed queries. See [Replication](../../engines/table-engines/mergetree-family/replication.md).
+
+Sets the time in seconds. If a replica lags more than the set value, this replica is not used.
+
+Default value: 300.
+
+Used when performing `SELECT` from a distributed table that points to replicated tables.
+
+## max_threads {#settings-max_threads}
+
+The maximum number of query processing threads, excluding threads for retrieving data from remote servers (see the ‘max_distributed_connections’ parameter).
+
+This parameter applies to threads that perform the same stages of the query processing pipeline in parallel.
+For example, when reading from a table, if it is possible to evaluate expressions with functions, filter with WHERE and pre-aggregate for GROUP BY in parallel using at least ‘max_threads’ number of threads, then ‘max_threads’ are used.
+
+Default value: the number of physical CPU cores.
+
+For queries that are completed quickly because of a LIMIT, you can set a lower ‘max_threads’. For example, if the necessary number of entries are located in every block and max_threads = 8, then 8 blocks are retrieved, although it would have been enough to read just one.
+
+The smaller the `max_threads` value, the less memory is consumed.
+
+## max_insert_threads {#settings-max-insert-threads}
+
+The maximum number of threads to execute the `INSERT SELECT` query.
+
+Possible values:
+
+-   0 (or 1) — `INSERT SELECT` no parallel execution.
+-   Positive integer. Bigger than 1.
+
+Default value: 0.
+
+Parallel `INSERT SELECT` has effect only if the `SELECT` part is executed in parallel, see [max_threads](#settings-max_threads) setting.
+Higher values will lead to higher memory usage.
+
+## max_compress_block_size {#max-compress-block-size}
+
+The maximum size of blocks of uncompressed data before compressing for writing to a table. By default, 1,048,576 (1 MiB). Specifying smaller block size generally leads to slightly reduced compression ratio, the compression and decompression speed increases slightly due to cache locality, and memory consumption is reduced.
+
+:::warning
+This is an expert-level setting, and you shouldn't change it if you're just getting started with ClickHouse.
+:::
+
+Don’t confuse blocks for compression (a chunk of memory consisting of bytes) with blocks for query processing (a set of rows from a table).
+
+## min_compress_block_size {#min-compress-block-size}
+
+For [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables. In order to reduce latency when processing queries, a block is compressed when writing the next mark if its size is at least `min_compress_block_size`. By default, 65,536.
+
+The actual size of the block, if the uncompressed data is less than `max_compress_block_size`, is no less than this value and no less than the volume of data for one mark.
+
+Let’s look at an example. Assume that `index_granularity` was set to 8192 during table creation.
+
+We are writing a UInt32-type column (4 bytes per value). When writing 8192 rows, the total will be 32 KB of data. Since min_compress_block_size = 65,536, a compressed block will be formed for every two marks.
+
+We are writing a URL column with the String type (average size of 60 bytes per value). When writing 8192 rows, the average will be slightly less than 500 KB of data. Since this is more than 65,536, a compressed block will be formed for each mark. In this case, when reading data from the disk in the range of a single mark, extra data won’t be decompressed.
+
+:::warning
+This is an expert-level setting, and you shouldn't change it if you're just getting started with ClickHouse.
+:::
+
+## max_query_size {#settings-max_query_size}
+
+The maximum part of a query that can be taken to RAM for parsing with the SQL parser.
+The INSERT query also contains data for INSERT that is processed by a separate stream parser (that consumes O(1) RAM), which is not included in this restriction.
+
+Default value: 256 KiB.
+
+## max_parser_depth {#max_parser_depth}
+
+Limits maximum recursion depth in the recursive descent parser. Allows controlling the stack size.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Recursion depth is unlimited.
+
+Default value: 1000.
+
+## interactive_delay {#interactive-delay}
+
+The interval in microseconds for checking whether request execution has been cancelled and sending the progress.
+
+Default value: 100,000 (checks for cancelling and sends the progress ten times per second).
+
+## connect_timeout, receive_timeout, send_timeout {#connect-timeout-receive-timeout-send-timeout}
+
+Timeouts in seconds on the socket used for communicating with the client.
+
+Default value: 10, 300, 300.
+
+## cancel_http_readonly_queries_on_client_close {#cancel-http-readonly-queries-on-client-close}
+
+Cancels HTTP read-only queries (e.g. SELECT) when a client closes the connection without waiting for the response.
+
+Default value: 0
+
+## poll_interval {#poll-interval}
+
+Lock in a wait loop for the specified number of seconds.
+
+Default value: 10.
+
+## max_distributed_connections {#max-distributed-connections}
+
+The maximum number of simultaneous connections with remote servers for distributed processing of a single query to a single Distributed table. We recommend setting a value no less than the number of servers in the cluster.
+
+Default value: 1024.
+
+The following parameters are only used when creating Distributed tables (and when launching a server), so there is no reason to change them at runtime.
+
+## distributed_connections_pool_size {#distributed-connections-pool-size}
+
+The maximum number of simultaneous connections with remote servers for distributed processing of all queries to a single Distributed table. We recommend setting a value no less than the number of servers in the cluster.
+
+Default value: 1024.
+
+## max_distributed_depth {#max-distributed-depth}
+
+Limits the maximum depth of recursive queries for [Distributed](../../engines/table-engines/special/distributed.md) tables.
+
+If the value is exceeded, the server throws an exception.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Unlimited depth.
+
+Default value: `5`.
+
+## max_replicated_fetches_network_bandwidth_for_server {#max_replicated_fetches_network_bandwidth_for_server}
+
+Limits the maximum speed of data exchange over the network in bytes per second for [replicated](../../engines/table-engines/mergetree-family/replication.md) fetches for the server. Only has meaning at server startup. You can also limit the speed for a particular table with [max_replicated_fetches_network_bandwidth](../../operations/settings/merge-tree-settings.md#max_replicated_fetches_network_bandwidth) setting.
+
+The setting isn't followed perfectly accurately.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Unlimited.
+
+Default value: `0`.
+
+**Usage**
+
+Could be used for throttling speed when replicating the data to add or replace new nodes.
+
+:::note
+60000000 bytes/s approximatly corresponds to 457 Mbps (60000000 / 1024 / 1024 * 8).
+:::
+
+## max_replicated_sends_network_bandwidth_for_server {#max_replicated_sends_network_bandwidth_for_server}
+
+Limits the maximum speed of data exchange over the network in bytes per second for [replicated](../../engines/table-engines/mergetree-family/replication.md) sends for the server. Only has meaning at server startup.  You can also limit the speed for a particular table with [max_replicated_sends_network_bandwidth](../../operations/settings/merge-tree-settings.md#max_replicated_sends_network_bandwidth) setting.
+
+The setting isn't followed perfectly accurately.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Unlimited.
+
+Default value: `0`.
+
+**Usage**
+
+Could be used for throttling speed when replicating the data to add or replace new nodes.
+
+:::note
+60000000 bytes/s approximatly corresponds to 457 Mbps (60000000 / 1024 / 1024 * 8).
+:::
+
+## connect_timeout_with_failover_ms {#connect-timeout-with-failover-ms}
+
+The timeout in milliseconds for connecting to a remote server for a Distributed table engine, if the ‘shard’ and ‘replica’ sections are used in the cluster definition.
+If unsuccessful, several attempts are made to connect to various replicas.
+
+Default value: 50.
+
+## connection_pool_max_wait_ms {#connection-pool-max-wait-ms}
+
+The wait time in milliseconds for a connection when the connection pool is full.
+
+Possible values:
+
+- Positive integer.
+- 0 — Infinite timeout.
+
+Default value: 0.
+
+## connections_with_failover_max_tries {#connections-with-failover-max-tries}
+
+The maximum number of connection attempts with each replica for the Distributed table engine.
+
+Default value: 3.
+
+## extremes {#extremes}
+
+Whether to count extreme values (the minimums and maximums in columns of a query result). Accepts 0 or 1. By default, 0 (disabled).
+For more information, see the section “Extreme values”.
+
+## kafka_max_wait_ms {#kafka-max-wait-ms}
+
+The wait time in milliseconds for reading messages from [Kafka](../../engines/table-engines/integrations/kafka.md#kafka) before retry.
+
+Possible values:
+
+- Positive integer.
+- 0 — Infinite timeout.
+
+Default value: 5000.
+
+See also:
+
+-   [Apache Kafka](https://kafka.apache.org/)
+
+## use_uncompressed_cache {#setting-use_uncompressed_cache}
+
+Whether to use a cache of uncompressed blocks. Accepts 0 or 1. By default, 0 (disabled).
+Using the uncompressed cache (only for tables in the MergeTree family) can significantly reduce latency and increase throughput when working with a large number of short queries. Enable this setting for users who send frequent short requests. Also pay attention to the [uncompressed_cache_size](../../operations/server-configuration-parameters/settings.md#server-settings-uncompressed_cache_size) configuration parameter (only set in the config file) – the size of uncompressed cache blocks. By default, it is 8 GiB. The uncompressed cache is filled in as needed and the least-used data is automatically deleted.
+
+For queries that read at least a somewhat large volume of data (one million rows or more), the uncompressed cache is disabled automatically to save space for truly small queries. This means that you can keep the ‘use_uncompressed_cache’ setting always set to 1.
+
+## replace_running_query {#replace-running-query}
+
+When using the HTTP interface, the ‘query_id’ parameter can be passed. This is any string that serves as the query identifier.
+If a query from the same user with the same ‘query_id’ already exists at this time, the behaviour depends on the ‘replace_running_query’ parameter.
+
+`0` (default) – Throw an exception (do not allow the query to run if a query with the same ‘query_id’ is already running).
+
+`1` – Cancel the old query and start running the new one.
+
+Set this parameter to 1 for implementing suggestions for segmentation conditions. After entering the next character, if the old query hasn’t finished yet, it should be cancelled.
+
+## replace_running_query_max_wait_ms {#replace-running-query-max-wait-ms}
+
+The wait time for running the query with the same `query_id` to finish, when the [replace_running_query](#replace-running-query) setting is active.
+
+Possible values:
+
+- Positive integer.
+- 0 — Throwing an exception that does not allow to run a new query if the server already executes a query with the same `query_id`.
+
+Default value: 5000.
+
+## stream_flush_interval_ms {#stream-flush-interval-ms}
+
+Works for tables with streaming in the case of a timeout, or when a thread generates [max_insert_block_size](#settings-max_insert_block_size) rows.
+
+The default value is 7500.
+
+The smaller the value, the more often data is flushed into the table. Setting the value too low leads to poor performance.
+
+## load_balancing {#settings-load_balancing}
+
+Specifies the algorithm of replicas selection that is used for distributed query processing.
+
+ClickHouse supports the following algorithms of choosing replicas:
+
+-   [Random](#load_balancing-random) (by default)
+-   [Nearest hostname](#load_balancing-nearest_hostname)
+-   [In order](#load_balancing-in_order)
+-   [First or random](#load_balancing-first_or_random)
+-   [Round robin](#load_balancing-round_robin)
+
+See also:
+
+-   [distributed_replica_max_ignored_errors](#settings-distributed_replica_max_ignored_errors)
+
+### Random (by Default) {#load_balancing-random}
+
+``` sql
+load_balancing = random
+```
+
+The number of errors is counted for each replica. The query is sent to the replica with the fewest errors, and if there are several of these, to anyone of them.
+Disadvantages: Server proximity is not accounted for; if the replicas have different data, you will also get different data.
+
+### Nearest Hostname {#load_balancing-nearest_hostname}
+
+``` sql
+load_balancing = nearest_hostname
+```
+
+The number of errors is counted for each replica. Every 5 minutes, the number of errors is integrally divided by 2. Thus, the number of errors is calculated for a recent time with exponential smoothing. If there is one replica with a minimal number of errors (i.e. errors occurred recently on the other replicas), the query is sent to it. If there are multiple replicas with the same minimal number of errors, the query is sent to the replica with a hostname that is most similar to the server’s hostname in the config file (for the number of different characters in identical positions, up to the minimum length of both hostnames).
+
+For instance, example01-01-1 and example01-01-2 are different in one position, while example01-01-1 and example01-02-2 differ in two places.
+This method might seem primitive, but it does not require external data about network topology, and it does not compare IP addresses, which would be complicated for our IPv6 addresses.
+
+Thus, if there are equivalent replicas, the closest one by name is preferred.
+We can also assume that when sending a query to the same server, in the absence of failures, a distributed query will also go to the same servers. So even if different data is placed on the replicas, the query will return mostly the same results.
+
+### In Order {#load_balancing-in_order}
+
+``` sql
+load_balancing = in_order
+```
+
+Replicas with the same number of errors are accessed in the same order as they are specified in the configuration.
+This method is appropriate when you know exactly which replica is preferable.
+
+### First or Random {#load_balancing-first_or_random}
+
+``` sql
+load_balancing = first_or_random
+```
+
+This algorithm chooses the first replica in the set or a random replica if the first is unavailable. It’s effective in cross-replication topology setups, but useless in other configurations.
+
+The `first_or_random` algorithm solves the problem of the `in_order` algorithm. With `in_order`, if one replica goes down, the next one gets a double load while the remaining replicas handle the usual amount of traffic. When using the `first_or_random` algorithm, the load is evenly distributed among replicas that are still available.
+
+It's possible to explicitly define what the first replica is by using the setting `load_balancing_first_offset`. This gives more control to rebalance query workloads among replicas.
+
+### Round Robin {#load_balancing-round_robin}
+
+``` sql
+load_balancing = round_robin
+```
+
+This algorithm uses a round-robin policy across replicas with the same number of errors (only the queries with `round_robin` policy is accounted).
+
+## prefer_localhost_replica {#settings-prefer-localhost-replica}
+
+Enables/disables preferable using the localhost replica when processing distributed queries.
+
+Possible values:
+
+-   1 — ClickHouse always sends a query to the localhost replica if it exists.
+-   0 — ClickHouse uses the balancing strategy specified by the [load_balancing](#settings-load_balancing) setting.
+
+Default value: 1.
+
+:::warning
+Disable this setting if you use [max_parallel_replicas](#settings-max_parallel_replicas).
+:::
+
+## totals_mode {#totals-mode}
+
+How to calculate TOTALS when HAVING is present, as well as when max_rows_to_group_by and group_by_overflow_mode = ‘any’ are present.
+See the section “WITH TOTALS modifier”.
+
+## totals_auto_threshold {#totals-auto-threshold}
+
+The threshold for `totals_mode = 'auto'`.
+See the section “WITH TOTALS modifier”.
+
+## max_parallel_replicas {#settings-max_parallel_replicas}
+
+The maximum number of replicas for each shard when executing a query.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `1`.
+
+**Additional Info**
+
+This setting is useful for replicated tables with a sampling key. A query may be processed faster if it is executed on several servers in parallel. But the query performance may degrade in the following cases:
+
+- The position of the sampling key in the partitioning key does not allow efficient range scans.
+- Adding a sampling key to the table makes filtering by other columns less efficient.
+- The sampling key is an expression that is expensive to calculate.
+- The cluster latency distribution has a long tail, so that querying more servers increases the query overall latency.
+
+:::warning
+This setting will produce incorrect results when joins or subqueries are involved, and all tables don't meet certain requirements. See [Distributed Subqueries and max_parallel_replicas](../../sql-reference/operators/in.md#max_parallel_replica-subqueries) for more details.
+:::
+
+## compile_expressions {#compile-expressions}
+
+Enables or disables compilation of frequently used simple functions and operators to native code with LLVM at runtime.
+
+Possible values:
+
+- 0 — Disabled.
+- 1 — Enabled.
+
+Default value: `1`.
+
+## min_count_to_compile_expression {#min-count-to-compile-expression}
+
+Minimum count of executing same expression before it is get compiled.
+
+Default value: `3`.
+
+## compile_aggregate_expressions {#compile_aggregate_expressions}
+
+Enables or disables JIT-compilation of aggregate functions to native code. Enabling this setting can improve the performance.
+
+Possible values:
+
+-   0 — Aggregation is done without JIT compilation.
+-   1 — Aggregation is done using JIT compilation.
+
+Default value: `1`.
+
+**See Also**
+
+-   [min_count_to_compile_aggregate_expression](#min_count_to_compile_aggregate_expression)
+
+## min_count_to_compile_aggregate_expression {#min_count_to_compile_aggregate_expression}
+
+The minimum number of identical aggregate expressions to start JIT-compilation. Works only if the [compile_aggregate_expressions](#compile_aggregate_expressions) setting is enabled.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Identical aggregate expressions are always JIT-compiled.
+
+Default value: `3`.
+
+## output_format_json_quote_64bit_integers {#session_settings-output_format_json_quote_64bit_integers}
+
+Controls quoting of 64-bit or bigger [integers](../../sql-reference/data-types/int-uint.md) (like `UInt64` or `Int128`) when they are output in a [JSON](../../interfaces/formats.md#json) format.
+Such integers are enclosed in quotes by default. This behavior is compatible with most JavaScript implementations.
+
+Possible values:
+
+-   0 — Integers are output without quotes.
+-   1 — Integers are enclosed in quotes.
+
+Default value: 1.
+
+## output_format_json_quote_denormals {#settings-output_format_json_quote_denormals}
+
+Enables `+nan`, `-nan`, `+inf`, `-inf` outputs in [JSON](../../interfaces/formats.md#json) output format.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+**Example**
+
+Consider the following table `account_orders`:
+
+```text
+┌─id─┬─name───┬─duration─┬─period─┬─area─┐
+│  1 │ Andrew │       20 │      0 │  400 │
+│  2 │ John   │       40 │      0 │    0 │
+│  3 │ Bob    │       15 │      0 │ -100 │
+└────┴────────┴──────────┴────────┴──────┘
+```
+
+When `output_format_json_quote_denormals = 0`, the query returns `null` values in output:
+
+```sql
+SELECT area/period FROM account_orders FORMAT JSON;
+```
+
+```json
+{
+        "meta":
+        [
+                {
+                        "name": "divide(area, period)",
+                        "type": "Float64"
+                }
+        ],
+
+        "data":
+        [
+                {
+                        "divide(area, period)": null
+                },
+                {
+                        "divide(area, period)": null
+                },
+                {
+                        "divide(area, period)": null
+                }
+        ],
+
+        "rows": 3,
+
+        "statistics":
+        {
+                "elapsed": 0.003648093,
+                "rows_read": 3,
+                "bytes_read": 24
+        }
+}
+```
+
+When `output_format_json_quote_denormals = 1`, the query returns:
+
+```json
+{
+        "meta":
+        [
+                {
+                        "name": "divide(area, period)",
+                        "type": "Float64"
+                }
+        ],
+
+        "data":
+        [
+                {
+                        "divide(area, period)": "inf"
+                },
+                {
+                        "divide(area, period)": "-nan"
+                },
+                {
+                        "divide(area, period)": "-inf"
+                }
+        ],
+
+        "rows": 3,
+
+        "statistics":
+        {
+                "elapsed": 0.000070241,
+                "rows_read": 3,
+                "bytes_read": 24
+        }
+}
+```
+
+## format_csv_delimiter {#settings-format_csv_delimiter}
+
+The character is interpreted as a delimiter in the CSV data. By default, the delimiter is `,`.
+
+## input_format_csv_enum_as_number {#settings-input_format_csv_enum_as_number}
+
+When enabled, always treat enum values as enum ids for CSV input format. It's recommended to enable this setting if data contains only enum ids to optimize enum parsing.
+
+Possible values:
+
+-   0 — Enum values are parsed as values or as enum IDs.
+-   1 — Enum values are parsed only as enum IDs.
+
+Default value: 0.
+
+**Examples**
+
+Consider the table:
+
+```sql
+CREATE TABLE table_with_enum_column_for_csv_insert (Id Int32,Value Enum('first' = 1, 'second' = 2)) ENGINE=Memory();
+```
+
+When the `input_format_csv_enum_as_number` setting is enabled:
+
+Query:
+
+```sql
+SET input_format_csv_enum_as_number = 1;
+INSERT INTO table_with_enum_column_for_csv_insert FORMAT CSV 102,2
+```
+
+Result:
+
+```text
+┌──Id─┬─Value──┐
+│ 102 │ second │
+└─────┴────────┘
+```
+
+Query:
+
+```sql
+SET input_format_csv_enum_as_number = 1;
+INSERT INTO table_with_enum_column_for_csv_insert FORMAT CSV 103,'first'
+```
+
+throws an exception.
+
+When the `input_format_csv_enum_as_number` setting is disabled:
+
+Query:
+
+```sql
+SET input_format_csv_enum_as_number = 0;
+INSERT INTO table_with_enum_column_for_csv_insert FORMAT CSV 102,2
+INSERT INTO table_with_enum_column_for_csv_insert FORMAT CSV 103,'first'
+SELECT * FROM table_with_enum_column_for_csv_insert;
+```
+
+Result:
+
+```text
+┌──Id─┬─Value──┐
+│ 102 │ second │
+└─────┴────────┘
+┌──Id─┬─Value─┐
+│ 103 │ first │
+└─────┴───────┘
+```
+
+## output_format_csv_crlf_end_of_line {#settings-output-format-csv-crlf-end-of-line}
+
+Use DOS/Windows-style line separator (CRLF) in CSV instead of Unix style (LF).
+
+## output_format_tsv_crlf_end_of_line {#settings-output-format-tsv-crlf-end-of-line}
+
+Use DOC/Windows-style line separator (CRLF) in TSV instead of Unix style (LF).
+
+## insert_quorum {#settings-insert_quorum}
+
+Enables the quorum writes.
+
+-   If `insert_quorum < 2`, the quorum writes are disabled.
+-   If `insert_quorum >= 2`, the quorum writes are enabled.
+
+Default value: 0.
+
+Quorum writes
+
+`INSERT` succeeds only when ClickHouse manages to correctly write data to the `insert_quorum` of replicas during the `insert_quorum_timeout`. If for any reason the number of replicas with successful writes does not reach the `insert_quorum`, the write is considered failed and ClickHouse will delete the inserted block from all the replicas where data has already been written.
+
+When `insert_quorum_parallel` is disabled, all replicas in the quorum are consistent, i.e. they contain data from all previous `INSERT` queries (the `INSERT` sequence is linearized). When reading data written using `insert_quorum` and `insert_quorum_parallel` is disabled, you can turn on sequential consistency for `SELECT` queries using [select_sequential_consistency](#settings-select_sequential_consistency).
+
+ClickHouse generates an exception:
+
+-   If the number of available replicas at the time of the query is less than the `insert_quorum`.
+-   When `insert_quorum_parallel` is disabled and an attempt to write data is made when the previous block has not yet been inserted in `insert_quorum` of replicas. This situation may occur if the user tries to perform another `INSERT` query to the same table before the previous one with `insert_quorum` is completed.
+
+See also:
+
+-   [insert_quorum_timeout](#settings-insert_quorum_timeout)
+-   [insert_quorum_parallel](#settings-insert_quorum_parallel)
+-   [select_sequential_consistency](#settings-select_sequential_consistency)
+
+## insert_quorum_timeout {#settings-insert_quorum_timeout}
+
+Write to a quorum timeout in milliseconds. If the timeout has passed and no write has taken place yet, ClickHouse will generate an exception and the client must repeat the query to write the same block to the same or any other replica.
+
+Default value: 600 000 milliseconds (ten minutes).
+
+See also:
+
+-   [insert_quorum](#settings-insert_quorum)
+-   [insert_quorum_parallel](#settings-insert_quorum_parallel)
+-   [select_sequential_consistency](#settings-select_sequential_consistency)
+
+## insert_quorum_parallel {#settings-insert_quorum_parallel}
+
+Enables or disables parallelism for quorum `INSERT` queries. If enabled, additional `INSERT` queries can be sent while previous queries have not yet finished. If disabled, additional writes to the same table will be rejected.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1.
+
+See also:
+
+-   [insert_quorum](#settings-insert_quorum)
+-   [insert_quorum_timeout](#settings-insert_quorum_timeout)
+-   [select_sequential_consistency](#settings-select_sequential_consistency)
+
+## select_sequential_consistency {#settings-select_sequential_consistency}
+
+Enables or disables sequential consistency for `SELECT` queries. Requires `insert_quorum_parallel` to be disabled (enabled by default).
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+Usage
+
+When sequential consistency is enabled, ClickHouse allows the client to execute the `SELECT` query only for those replicas that contain data from all previous `INSERT` queries executed with `insert_quorum`. If the client refers to a partial replica, ClickHouse will generate an exception. The SELECT query will not include data that has not yet been written to the quorum of replicas.
+
+When `insert_quorum_parallel` is enabled (the default), then `select_sequential_consistency` does not work. This is because parallel `INSERT` queries can be written to different sets of quorum replicas so there is no guarantee a single replica will have received all writes.
+
+See also:
+
+-   [insert_quorum](#settings-insert_quorum)
+-   [insert_quorum_timeout](#settings-insert_quorum_timeout)
+-   [insert_quorum_parallel](#settings-insert_quorum_parallel)
+
+## insert_deduplicate {#settings-insert-deduplicate}
+
+Enables or disables block deduplication of `INSERT` (for Replicated\* tables).
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1.
+
+By default, blocks inserted into replicated tables by the `INSERT` statement are deduplicated (see [Data Replication](../../engines/table-engines/mergetree-family/replication.md)).
+
+## deduplicate_blocks_in_dependent_materialized_views {#settings-deduplicate-blocks-in-dependent-materialized-views}
+
+Enables or disables the deduplication check for materialized views that receive data from Replicated\* tables.
+
+Possible values:
+
+      0 — Disabled.
+      1 — Enabled.
+
+Default value: 0.
+
+Usage
+
+By default, deduplication is not performed for materialized views but is done upstream, in the source table.
+If an INSERTed block is skipped due to deduplication in the source table, there will be no insertion into attached materialized views. This behaviour exists to enable the insertion of highly aggregated data into materialized views, for cases where inserted blocks are the same after materialized view aggregation but derived from different INSERTs into the source table.
+At the same time, this behaviour “breaks” `INSERT` idempotency. If an `INSERT` into the main table was successful and `INSERT` into a materialized view failed (e.g. because of communication failure with Zookeeper) a client will get an error and can retry the operation. However, the materialized view won’t receive the second insert because it will be discarded by deduplication in the main (source) table. The setting `deduplicate_blocks_in_dependent_materialized_views` allows for changing this behaviour. On retry, a materialized view will receive the repeat insert and will perform a deduplication check by itself,
+ignoring check result for the source table, and will insert rows lost because of the first failure.
+
+## insert_deduplication_token {#insert_deduplication_token}
+
+The setting allows a user to provide own deduplication semantic in MergeTree/ReplicatedMergeTree  
+For example, by providing a unique value for the setting in each INSERT statement,
+user can avoid the same inserted data being deduplicated.
+
+Possilbe values:
+
+-  Any string
+
+Default value: empty string (disabled)
+
+`insert_deduplication_token` is used for deduplication _only_ when not empty.
+
+Example:
+
+```sql
+CREATE TABLE test_table
+( A Int64 )
+ENGINE = MergeTree
+ORDER BY A
+SETTINGS non_replicated_deduplication_window = 100;
+
+INSERT INTO test_table Values SETTINGS insert_deduplication_token = 'test' (1);
+
+-- the next insert won't be deduplicated because insert_deduplication_token is different
+INSERT INTO test_table Values SETTINGS insert_deduplication_token = 'test1' (1);
+
+-- the next insert will be deduplicated because insert_deduplication_token 
+-- is the same as one of the previous
+INSERT INTO test_table Values SETTINGS insert_deduplication_token = 'test' (2);
+
+SELECT * FROM test_table
+
+┌─A─┐
+│ 1 │
+└───┘
+┌─A─┐
+│ 1 │
+└───┘
+```
+
+## max_network_bytes {#settings-max-network-bytes}
+
+Limits the data volume (in bytes) that is received or transmitted over the network when executing a query. This setting applies to every individual query.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Data volume control is disabled.
+
+Default value: 0.
+
+## max_network_bandwidth {#settings-max-network-bandwidth}
+
+Limits the speed of the data exchange over the network in bytes per second. This setting applies to every query.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Bandwidth control is disabled.
+
+Default value: 0.
+
+## max_network_bandwidth_for_user {#settings-max-network-bandwidth-for-user}
+
+Limits the speed of the data exchange over the network in bytes per second. This setting applies to all concurrently running queries performed by a single user.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Control of the data speed is disabled.
+
+Default value: 0.
+
+## max_network_bandwidth_for_all_users {#settings-max-network-bandwidth-for-all-users}
+
+Limits the speed that data is exchanged at over the network in bytes per second. This setting applies to all concurrently running queries on the server.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Control of the data speed is disabled.
+
+Default value: 0.
+
+## count_distinct_implementation {#settings-count_distinct_implementation}
+
+Specifies which of the `uniq*` functions should be used to perform the [COUNT(DISTINCT …)](../../sql-reference/aggregate-functions/reference/count.md#agg_function-count) construction.
+
+Possible values:
+
+-   [uniq](../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq)
+-   [uniqCombined](../../sql-reference/aggregate-functions/reference/uniqcombined.md#agg_function-uniqcombined)
+-   [uniqCombined64](../../sql-reference/aggregate-functions/reference/uniqcombined64.md#agg_function-uniqcombined64)
+-   [uniqHLL12](../../sql-reference/aggregate-functions/reference/uniqhll12.md#agg_function-uniqhll12)
+-   [uniqExact](../../sql-reference/aggregate-functions/reference/uniqexact.md#agg_function-uniqexact)
+
+Default value: `uniqExact`.
+
+## skip_unavailable_shards {#settings-skip_unavailable_shards}
+
+Enables or disables silently skipping of unavailable shards.
+
+Shard is considered unavailable if all its replicas are unavailable. A replica is unavailable in the following cases:
+
+-   ClickHouse can’t connect to replica for any reason.
+
+    When connecting to a replica, ClickHouse performs several attempts. If all these attempts fail, the replica is considered unavailable.
+
+-   Replica can’t be resolved through DNS.
+
+    If replica’s hostname can’t be resolved through DNS, it can indicate the following situations:
+
+    -   Replica’s host has no DNS record. It can occur in systems with dynamic DNS, for example, [Kubernetes](https://kubernetes.io), where nodes can be unresolvable during downtime, and this is not an error.
+
+    -   Configuration error. ClickHouse configuration file contains a wrong hostname.
+
+Possible values:
+
+-   1 — skipping enabled.
+
+    If a shard is unavailable, ClickHouse returns a result based on partial data and does not report node availability issues.
+
+-   0 — skipping disabled.
+
+    If a shard is unavailable, ClickHouse throws an exception.
+
+Default value: 0.
+
+## distributed_group_by_no_merge {#distributed-group-by-no-merge}
+
+Do not merge aggregation states from different servers for distributed query processing, you can use this in case it is for certain that there are different keys on different shards
+
+Possible values:
+
+-   `0` — Disabled (final query processing is done on the initiator node).
+-   `1` - Do not merge aggregation states from different servers for distributed query processing (query completelly processed on the shard, initiator only proxy the data), can be used in case it is for certain that there are different keys on different shards.
+-   `2` - Same as `1` but applies `ORDER BY` and `LIMIT` (it is not possible when the query processed completelly on the remote node, like for `distributed_group_by_no_merge=1`) on the initiator (can be used for queries with `ORDER BY` and/or `LIMIT`).
+
+Default value: `0`
+
+**Example**
+
+```sql
+SELECT *
+FROM remote('127.0.0.{2,3}', system.one)
+GROUP BY dummy
+LIMIT 1
+SETTINGS distributed_group_by_no_merge = 1
+FORMAT PrettyCompactMonoBlock
+
+┌─dummy─┐
+│     0 │
+│     0 │
+└───────┘
+```
+
+```sql
+SELECT *
+FROM remote('127.0.0.{2,3}', system.one)
+GROUP BY dummy
+LIMIT 1
+SETTINGS distributed_group_by_no_merge = 2
+FORMAT PrettyCompactMonoBlock
+
+┌─dummy─┐
+│     0 │
+└───────┘
+```
+
+## distributed_push_down_limit {#distributed-push-down-limit}
+
+Enables or disables [LIMIT](#limit) applying on each shard separatelly.
+
+This will allow to avoid:
+-  Sending extra rows over network;
+-  Processing rows behind the limit on the initiator.
+
+Starting from 21.9 version you cannot get inaccurate results anymore, since `distributed_push_down_limit` changes query execution only if at least one of the conditions met:
+-  [distributed_group_by_no_merge](#distributed-group-by-no-merge) > 0.
+-  Query **does not have** `GROUP BY`/`DISTINCT`/`LIMIT BY`, but it has `ORDER BY`/`LIMIT`.
+-  Query **has** `GROUP BY`/`DISTINCT`/`LIMIT BY` with `ORDER BY`/`LIMIT` and:
+    -  [optimize_skip_unused_shards](#optimize-skip-unused-shards) is enabled.
+    -  [optimize_distributed_group_by_sharding_key](#optimize-distributed-group-by-sharding-key) is enabled.
+
+Possible values:
+
+-  0 — Disabled.
+-  1 — Enabled.
+
+Default value: `1`.
+
+See also:
+
+-   [distributed_group_by_no_merge](#distributed-group-by-no-merge)
+-   [optimize_skip_unused_shards](#optimize-skip-unused-shards)
+-   [optimize_distributed_group_by_sharding_key](#optimize-distributed-group-by-sharding-key)
+
+## optimize_skip_unused_shards_limit {#optimize-skip-unused-shards-limit}
+
+Limit for number of sharding key values, turns off `optimize_skip_unused_shards` if the limit is reached.
+
+Too many values may require significant amount for processing, while the benefit is doubtful, since if you have huge number of values in `IN (...)`, then most likely the query will be sent to all shards anyway.
+
+Default value: 1000
+
+## optimize_skip_unused_shards {#optimize-skip-unused-shards}
+
+Enables or disables skipping of unused shards for [SELECT](../../sql-reference/statements/select/index.md) queries that have sharding key condition in `WHERE/PREWHERE` (assuming that the data is distributed by sharding key, otherwise a query yields incorrect result).
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0
+
+## optimize_skip_unused_shards_rewrite_in {#optimize-skip-unused-shards-rewrite-in}
+
+Rewrite IN in query for remote shards to exclude values that does not belong to the shard (requires optimize_skip_unused_shards).
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1 (since it requires `optimize_skip_unused_shards` anyway, which `0` by default)
+
+## allow_nondeterministic_optimize_skip_unused_shards {#allow-nondeterministic-optimize-skip-unused-shards}
+
+Allow nondeterministic (like `rand` or `dictGet`, since later has some caveats with updates) functions in sharding key.
+
+Possible values:
+
+-   0 — Disallowed.
+-   1 — Allowed.
+
+Default value: 0
+
+## optimize_skip_unused_shards_nesting {#optimize-skip-unused-shards-nesting}
+
+Controls [`optimize_skip_unused_shards`](#optimize-skip-unused-shards) (hence still requires [`optimize_skip_unused_shards`](#optimize-skip-unused-shards)) depends on the nesting level of the distributed query (case when you have `Distributed` table that look into another `Distributed` table).
+
+Possible values:
+
+-   0 — Disabled, `optimize_skip_unused_shards` works always.
+-   1 — Enables `optimize_skip_unused_shards` only for the first level.
+-   2 — Enables `optimize_skip_unused_shards` up to the second level.
+
+Default value: 0
+
+## force_optimize_skip_unused_shards {#force-optimize-skip-unused-shards}
+
+Enables or disables query execution if [optimize_skip_unused_shards](#optimize-skip-unused-shards) is enabled and skipping of unused shards is not possible. If the skipping is not possible and the setting is enabled, an exception will be thrown.
+
+Possible values:
+
+-   0 — Disabled. ClickHouse does not throw an exception.
+-   1 — Enabled. Query execution is disabled only if the table has a sharding key.
+-   2 — Enabled. Query execution is disabled regardless of whether a sharding key is defined for the table.
+
+Default value: 0
+
+## force_optimize_skip_unused_shards_nesting {#settings-force_optimize_skip_unused_shards_nesting}
+
+Controls [`force_optimize_skip_unused_shards`](#force-optimize-skip-unused-shards) (hence still requires [`force_optimize_skip_unused_shards`](#force-optimize-skip-unused-shards)) depends on the nesting level of the distributed query (case when you have `Distributed` table that look into another `Distributed` table).
+
+Possible values:
+
+-   0 - Disabled, `force_optimize_skip_unused_shards` works always.
+-   1 — Enables `force_optimize_skip_unused_shards` only for the first level.
+-   2 — Enables `force_optimize_skip_unused_shards` up to the second level.
+
+Default value: 0
+
+## optimize_distributed_group_by_sharding_key {#optimize-distributed-group-by-sharding-key}
+
+Optimize `GROUP BY sharding_key` queries, by avoiding costly aggregation on the initiator server (which will reduce memory usage for the query on the initiator server).
+
+The following types of queries are supported (and all combinations of them):
+
+- `SELECT DISTINCT [..., ]sharding_key[, ...] FROM dist`
+- `SELECT ... FROM dist GROUP BY sharding_key[, ...]`
+- `SELECT ... FROM dist GROUP BY sharding_key[, ...] ORDER BY x`
+- `SELECT ... FROM dist GROUP BY sharding_key[, ...] LIMIT 1`
+- `SELECT ... FROM dist GROUP BY sharding_key[, ...] LIMIT 1 BY x`
+
+The following types of queries are not supported (support for some of them may be added later):
+
+- `SELECT ... GROUP BY sharding_key[, ...] WITH TOTALS`
+- `SELECT ... GROUP BY sharding_key[, ...] WITH ROLLUP`
+- `SELECT ... GROUP BY sharding_key[, ...] WITH CUBE`
+- `SELECT ... GROUP BY sharding_key[, ...] SETTINGS extremes=1`
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0
+
+See also:
+
+-   [distributed_group_by_no_merge](#distributed-group-by-no-merge)
+-   [distributed_push_down_limit](#distributed-push-down-limit)
+-   [optimize_skip_unused_shards](#optimize-skip-unused-shards)
+
+:::note
+Right now it requires `optimize_skip_unused_shards` (the reason behind this is that one day it may be enabled by default, and it will work correctly only if data was inserted via Distributed table, i.e. data is distributed according to sharding_key).
+:::
+
+## optimize_throw_if_noop {#setting-optimize_throw_if_noop}
+
+Enables or disables throwing an exception if an [OPTIMIZE](../../sql-reference/statements/misc.md#misc_operations-optimize) query didn’t perform a merge.
+
+By default, `OPTIMIZE` returns successfully even if it didn’t do anything. This setting lets you differentiate these situations and get the reason in an exception message.
+
+Possible values:
+
+-   1 — Throwing an exception is enabled.
+-   0 — Throwing an exception is disabled.
+
+Default value: 0.
+
+## optimize_functions_to_subcolumns {#optimize-functions-to-subcolumns}
+
+Enables or disables optimization by transforming some functions to reading subcolumns. This reduces the amount of data to read.
+
+These functions can be transformed:
+
+-   [length](../../sql-reference/functions/array-functions.md#array_functions-length) to read the [size0](../../sql-reference/data-types/array.md#array-size) subcolumn.
+-   [empty](../../sql-reference/functions/array-functions.md#function-empty) to read the [size0](../../sql-reference/data-types/array.md#array-size) subcolumn.
+-   [notEmpty](../../sql-reference/functions/array-functions.md#function-notempty) to read the [size0](../../sql-reference/data-types/array.md#array-size) subcolumn.
+-   [isNull](../../sql-reference/operators/index.md#operator-is-null) to read the [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn.
+-   [isNotNull](../../sql-reference/operators/index.md#is-not-null) to read the [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn.
+-   [count](../../sql-reference/aggregate-functions/reference/count.md) to read the [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn.
+-   [mapKeys](../../sql-reference/functions/tuple-map-functions.md#mapkeys) to read the [keys](../../sql-reference/data-types/map.md#map-subcolumns) subcolumn.
+-   [mapValues](../../sql-reference/functions/tuple-map-functions.md#mapvalues) to read the [values](../../sql-reference/data-types/map.md#map-subcolumns) subcolumn.
+
+Possible values:
+
+-   0 — Optimization disabled.
+-   1 — Optimization enabled.
+
+Default value: `0`.
+
+## optimize_trivial_count_query {#optimize-trivial-count-query}
+
+Enables or disables the optimization to trivial query `SELECT count() FROM table` using metadata from MergeTree. If you need to use row-level security, disable this setting.
+
+Possible values:
+
+   - 0 — Optimization disabled.
+   - 1 — Optimization enabled.
+
+Default value: `1`.
+
+See also:
+
+-   [optimize_functions_to_subcolumns](#optimize-functions-to-subcolumns)
+
+## distributed_replica_error_half_life {#settings-distributed_replica_error_half_life}
+
+-   Type: seconds
+-   Default value: 60 seconds
+
+Controls how fast errors in distributed tables are zeroed. If a replica is unavailable for some time, accumulates 5 errors, and distributed_replica_error_half_life is set to 1 second, then the replica is considered normal 3 seconds after the last error.
+
+See also:
+
+-   [load_balancing](#load_balancing-round_robin)
+-   [Table engine Distributed](../../engines/table-engines/special/distributed.md)
+-   [distributed_replica_error_cap](#settings-distributed_replica_error_cap)
+-   [distributed_replica_max_ignored_errors](#settings-distributed_replica_max_ignored_errors)
+
+## distributed_replica_error_cap {#settings-distributed_replica_error_cap}
+
+-   Type: unsigned int
+-   Default value: 1000
+
+The error count of each replica is capped at this value, preventing a single replica from accumulating too many errors.
+
+See also:
+
+-   [load_balancing](#load_balancing-round_robin)
+-   [Table engine Distributed](../../engines/table-engines/special/distributed.md)
+-   [distributed_replica_error_half_life](#settings-distributed_replica_error_half_life)
+-   [distributed_replica_max_ignored_errors](#settings-distributed_replica_max_ignored_errors)
+
+## distributed_replica_max_ignored_errors {#settings-distributed_replica_max_ignored_errors}
+
+-   Type: unsigned int
+-   Default value: 0
+
+The number of errors that will be ignored while choosing replicas (according to `load_balancing` algorithm).
+
+See also:
+
+-   [load_balancing](#load_balancing-round_robin)
+-   [Table engine Distributed](../../engines/table-engines/special/distributed.md)
+-   [distributed_replica_error_cap](#settings-distributed_replica_error_cap)
+-   [distributed_replica_error_half_life](#settings-distributed_replica_error_half_life)
+
+## distributed_directory_monitor_sleep_time_ms {#distributed_directory_monitor_sleep_time_ms}
+
+Base interval for the [Distributed](../../engines/table-engines/special/distributed.md) table engine to send data. The actual interval grows exponentially in the event of errors.
+
+Possible values:
+
+-   A positive integer number of milliseconds.
+
+Default value: 100 milliseconds.
+
+## distributed_directory_monitor_max_sleep_time_ms {#distributed_directory_monitor_max_sleep_time_ms}
+
+Maximum interval for the [Distributed](../../engines/table-engines/special/distributed.md) table engine to send data. Limits exponential growth of the interval set in the [distributed_directory_monitor_sleep_time_ms](#distributed_directory_monitor_sleep_time_ms) setting.
+
+Possible values:
+
+-   A positive integer number of milliseconds.
+
+Default value: 30000 milliseconds (30 seconds).
+
+## distributed_directory_monitor_batch_inserts {#distributed_directory_monitor_batch_inserts}
+
+Enables/disables inserted data sending in batches.
+
+When batch sending is enabled, the [Distributed](../../engines/table-engines/special/distributed.md) table engine tries to send multiple files of inserted data in one operation instead of sending them separately. Batch sending improves cluster performance by better-utilizing server and network resources.
+
+Possible values:
+
+-   1 — Enabled.
+-   0 — Disabled.
+
+Default value: 0.
+
+## distributed_directory_monitor_split_batch_on_failure {#distributed_directory_monitor_split_batch_on_failure}
+
+Enables/disables splitting batches on failures.
+
+Sometimes sending particular batch to the remote shard may fail, because of some complex pipeline after (i.e. `MATERIALIZED VIEW` with `GROUP BY`) due to `Memory limit exceeded` or similar errors. In this case, retrying will not help (and this will stuck distributed sends for the table) but sending files from that batch one by one may succeed INSERT.
+
+So installing this setting to `1` will disable batching for such batches (i.e. temporary disables `distributed_directory_monitor_batch_inserts` for failed batches).
+
+Possible values:
+
+-   1 — Enabled.
+-   0 — Disabled.
+
+Default value: 0.
+
+:::note
+This setting also affects broken batches (that may appears because of abnormal server (machine) termination and no `fsync_after_insert`/`fsync_directories` for [Distributed](../../engines/table-engines/special/distributed.md) table engine).
+:::
+
+:::warning
+You should not rely on automatic batch splitting, since this may hurt performance.
+:::
+
+## os_thread_priority {#setting-os-thread-priority}
+
+Sets the priority ([nice](https://en.wikipedia.org/wiki/Nice_(Unix))) for threads that execute queries. The OS scheduler considers this priority when choosing the next thread to run on each available CPU core.
+
+:::warning
+To use this setting, you need to set the `CAP_SYS_NICE` capability. The `clickhouse-server` package sets it up during installation. Some virtual environments do not allow you to set the `CAP_SYS_NICE` capability. In this case, `clickhouse-server` shows a message about it at the start.
+:::
+
+Possible values:
+
+-   You can set values in the range `[-20, 19]`.
+
+Lower values mean higher priority. Threads with low `nice` priority values are executed more frequently than threads with high values. High values are preferable for long-running non-interactive queries because it allows them to quickly give up resources in favour of short interactive queries when they arrive.
+
+Default value: 0.
+
+## query_profiler_real_time_period_ns {#query_profiler_real_time_period_ns}
+
+Sets the period for a real clock timer of the [query profiler](../../operations/optimizing-performance/sampling-query-profiler.md). Real clock timer counts wall-clock time.
+
+Possible values:
+
+-   Positive integer number, in nanoseconds.
+
+    Recommended values:
+
+            - 10000000 (100 times a second) nanoseconds and less for single queries.
+            - 1000000000 (once a second) for cluster-wide profiling.
+
+-   0 for turning off the timer.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+Default value: 1000000000 nanoseconds (once a second).
+
+See also:
+
+-   System table [trace_log](../../operations/system-tables/trace_log.md#system_tables-trace_log)
+
+## query_profiler_cpu_time_period_ns {#query_profiler_cpu_time_period_ns}
+
+Sets the period for a CPU clock timer of the [query profiler](../../operations/optimizing-performance/sampling-query-profiler.md). This timer counts only CPU time.
+
+Possible values:
+
+-   A positive integer number of nanoseconds.
+
+    Recommended values:
+
+            - 10000000 (100 times a second) nanoseconds and more for single queries.
+            - 1000000000 (once a second) for cluster-wide profiling.
+
+-   0 for turning off the timer.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+Default value: 1000000000 nanoseconds.
+
+See also:
+
+-   System table [trace_log](../../operations/system-tables/trace_log.md#system_tables-trace_log)
+
+## allow_introspection_functions {#settings-allow_introspection_functions}
+
+Enables or disables [introspections functions](../../sql-reference/functions/introspection.md) for query profiling.
+
+Possible values:
+
+-   1 — Introspection functions enabled.
+-   0 — Introspection functions disabled.
+
+Default value: 0.
+
+**See Also**
+
+-   [Sampling Query Profiler](../../operations/optimizing-performance/sampling-query-profiler.md)
+-   System table [trace_log](../../operations/system-tables/trace_log.md#system_tables-trace_log)
+
+## input_format_parallel_parsing {#input-format-parallel-parsing}
+
+Enables or disables order-preserving parallel parsing of data formats. Supported only for [TSV](../../interfaces/formats.md#tabseparated), [TKSV](../../interfaces/formats.md#tskv), [CSV](../../interfaces/formats.md#csv) and [JSONEachRow](../../interfaces/formats.md#jsoneachrow) formats.
+
+Possible values:
+
+-   1 — Enabled.
+-   0 — Disabled.
+
+Default value: `1`.
+
+## output_format_parallel_formatting {#output-format-parallel-formatting}
+
+Enables or disables parallel formatting of data formats. Supported only for [TSV](../../interfaces/formats.md#tabseparated), [TKSV](../../interfaces/formats.md#tskv), [CSV](../../interfaces/formats.md#csv) and [JSONEachRow](../../interfaces/formats.md#jsoneachrow) formats.
+
+Possible values:
+
+-   1 — Enabled.
+-   0 — Disabled.
+
+Default value: `1`.
+
+## min_chunk_bytes_for_parallel_parsing {#min-chunk-bytes-for-parallel-parsing}
+
+-   Type: unsigned int
+-   Default value: 1 MiB
+
+The minimum chunk size in bytes, which each thread will parse in parallel.
+
+## output_format_avro_codec {#settings-output_format_avro_codec}
+
+Sets the compression codec used for output Avro file.
+
+Type: string
+
+Possible values:
+
+-   `null` — No compression
+-   `deflate` — Compress with Deflate (zlib)
+-   `snappy` — Compress with [Snappy](https://google.github.io/snappy/)
+
+Default value: `snappy` (if available) or `deflate`.
+
+## output_format_avro_sync_interval {#settings-output_format_avro_sync_interval}
+
+Sets minimum data size (in bytes) between synchronization markers for output Avro file.
+
+Type: unsigned int
+
+Possible values: 32 (32 bytes) - 1073741824 (1 GiB)
+
+Default value: 32768 (32 KiB)
+
+## output_format_avro_string_column_pattern {#output_format_avro_string_column_pattern}
+
+Regexp of column names of type String to output as Avro `string` (default is `bytes`).
+RE2 syntax is supported.
+
+Type: string
+
+## format_avro_schema_registry_url {#format_avro_schema_registry_url}
+
+Sets [Confluent Schema Registry](https://docs.confluent.io/current/schema-registry/index.html) URL to use with [AvroConfluent](../../interfaces/formats.md#data-format-avro-confluent) format.
+
+Default value: `Empty`.
+
+## input_format_avro_allow_missing_fields {#input_format_avro_allow_missing_fields}
+
+Enables using fields that are not specified in [Avro](../../interfaces/formats.md#data-format-avro) or [AvroConfluent](../../interfaces/formats.md#data-format-avro-confluent) format schema. When a field is not found in the schema, ClickHouse uses the default value instead of throwing an exception.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+## background_pool_size {#background_pool_size}
+
+Sets the number of threads performing background operations in table engines (for example, merges in [MergeTree engine](../../engines/table-engines/mergetree-family/index.md) tables). This setting is applied from the `default` profile at the ClickHouse server start and can’t be changed in a user session. By adjusting this setting, you manage CPU and disk load. Smaller pool size utilizes less CPU and disk resources, but background processes advance slower which might eventually impact query performance.
+
+Before changing it, please also take a look at related [MergeTree settings](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-merge_tree), such as `number_of_free_entries_in_pool_to_lower_max_size_of_merge` and `number_of_free_entries_in_pool_to_execute_mutation`.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 16.
+
+## merge_selecting_sleep_ms {#merge_selecting_sleep_ms}
+
+Sleep time for merge selecting when no part is selected. A lower setting triggers selecting tasks in `background_schedule_pool` frequently, which results in a large number of requests to Zookeeper in large-scale clusters.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: `5000`.
+
+## parallel_distributed_insert_select {#parallel_distributed_insert_select}
+
+Enables parallel distributed `INSERT ... SELECT` query.
+
+If we execute `INSERT INTO distributed_table_a SELECT ... FROM distributed_table_b` queries and both tables use the same cluster, and both tables are either [replicated](../../engines/table-engines/mergetree-family/replication.md) or non-replicated, then this query is processed locally on every shard.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — `SELECT` will be executed on each shard from the underlying table of the distributed engine.
+-   2 — `SELECT` and `INSERT` will be executed on each shard from/to the underlying table of the distributed engine.
+
+Default value: 0.
+
+## insert_distributed_sync {#insert_distributed_sync}
+
+Enables or disables synchronous data insertion into a [Distributed](../../engines/table-engines/special/distributed.md#distributed) table.
+
+By default, when inserting data into a `Distributed` table, the ClickHouse server sends data to cluster nodes in asynchronous mode. When `insert_distributed_sync=1`, the data is processed synchronously, and the `INSERT` operation succeeds only after all the data is saved on all shards (at least one replica for each shard if `internal_replication` is true).
+
+Possible values:
+
+-   0 — Data is inserted in asynchronous mode.
+-   1 — Data is inserted in synchronous mode.
+
+Default value: `0`.
+
+**See Also**
+
+-   [Distributed Table Engine](../../engines/table-engines/special/distributed.md#distributed)
+-   [Managing Distributed Tables](../../sql-reference/statements/system.md#query-language-system-distributed)
+
+## insert_distributed_one_random_shard {#insert_distributed_one_random_shard}
+
+Enables or disables random shard insertion into a [Distributed](../../engines/table-engines/special/distributed.md#distributed) table when there is no distributed key.
+
+By default, when inserting data into a `Distributed` table with more than one shard, the ClickHouse server will reject any insertion request if there is no distributed key. When `insert_distributed_one_random_shard = 1`, insertions are allowed and data is forwarded randomly among all shards.
+
+Possible values:
+
+-   0 — Insertion is rejected if there are multiple shards and no distributed key is given.
+-   1 — Insertion is done randomly among all available shards when no distributed key is given.
+
+Default value: `0`.
+
+## insert_shard_id {#insert_shard_id}
+
+If not `0`, specifies the shard of [Distributed](../../engines/table-engines/special/distributed.md#distributed) table into which the data will be inserted synchronously.
+
+If `insert_shard_id` value is incorrect, the server will throw an exception.
+
+To get the number of shards on `requested_cluster`, you can check server config or use this query:
+
+``` sql
+SELECT uniq(shard_num) FROM system.clusters WHERE cluster = 'requested_cluster';
+```
+
+Possible values:
+
+-   0 — Disabled.
+-   Any number from `1` to `shards_num` of corresponding [Distributed](../../engines/table-engines/special/distributed.md#distributed) table.
+
+Default value: `0`.
+
+**Example**
+
+Query:
+
+```sql
+CREATE TABLE x AS system.numbers ENGINE = MergeTree ORDER BY number;
+CREATE TABLE x_dist AS x ENGINE = Distributed('test_cluster_two_shards_localhost', currentDatabase(), x);
+INSERT INTO x_dist SELECT * FROM numbers(5) SETTINGS insert_shard_id = 1;
+SELECT * FROM x_dist ORDER BY number ASC;
+```
+
+Result:
+
+``` text
+┌─number─┐
+│      0 │
+│      0 │
+│      1 │
+│      1 │
+│      2 │
+│      2 │
+│      3 │
+│      3 │
+│      4 │
+│      4 │
+└────────┘
+```
+
+## use_compact_format_in_distributed_parts_names {#use_compact_format_in_distributed_parts_names}
+
+Uses compact format for storing blocks for async (`insert_distributed_sync`) INSERT into tables with `Distributed` engine.
+
+Possible values:
+
+-   0 — Uses `user[:password]@host:port#default_database` directory format.
+-   1 — Uses `[shard{shard_index}[_replica{replica_index}]]` directory format.
+
+Default value: `1`.
+
+:::note
+- with `use_compact_format_in_distributed_parts_names=0` changes from cluster definition will not be applied for async INSERT.
+- with `use_compact_format_in_distributed_parts_names=1` changing the order of the nodes in the cluster definition, will change the `shard_index`/`replica_index` so be aware.
+:::
+
+## background_buffer_flush_schedule_pool_size {#background_buffer_flush_schedule_pool_size}
+
+Sets the number of threads performing background flush in [Buffer](../../engines/table-engines/special/buffer.md)-engine tables. This setting is applied at the ClickHouse server start and can’t be changed in a user session.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 16.
+
+## background_move_pool_size {#background_move_pool_size}
+
+Sets the number of threads performing background moves of data parts for [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes)-engine tables. This setting is applied at the ClickHouse server start and can’t be changed in a user session.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 8.
+
+## background_schedule_pool_size {#background_schedule_pool_size}
+
+Sets the number of threads performing background tasks for [replicated](../../engines/table-engines/mergetree-family/replication.md) tables, [Kafka](../../engines/table-engines/integrations/kafka.md) streaming, [DNS cache updates](../../operations/server-configuration-parameters/settings.md#server-settings-dns-cache-update-period). This setting is applied at ClickHouse server start and can’t be changed in a user session.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 128.
+
+## background_fetches_pool_size {#background_fetches_pool_size}
+
+Sets the number of threads performing background fetches for [replicated](../../engines/table-engines/mergetree-family/replication.md) tables. This setting is applied at the ClickHouse server start and can’t be changed in a user session. For production usage with frequent small insertions or slow ZooKeeper cluster is recommended to use default value.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 8.
+
+## always_fetch_merged_part {#always_fetch_merged_part}
+
+Prohibits data parts merging in [Replicated\*MergeTree](../../engines/table-engines/mergetree-family/replication.md)-engine tables.
+
+When merging is prohibited, the replica never merges parts and always downloads merged parts from other replicas. If there is no required data yet, the replica waits for it. CPU and disk load on the replica server decreases, but the network load on the cluster increases. This setting can be useful on servers with relatively weak CPUs or slow disks, such as servers for backups storage.
+
+Possible values:
+
+-   0 — `Replicated*MergeTree`-engine tables merge data parts at the replica.
+-   1 — `Replicated*MergeTree`-engine tables do not merge data parts at the replica. The tables download merged data parts from other replicas.
+
+Default value: 0.
+
+**See Also**
+
+-   [Data Replication](../../engines/table-engines/mergetree-family/replication.md)
+
+## background_distributed_schedule_pool_size {#background_distributed_schedule_pool_size}
+
+Sets the number of threads performing background tasks for [distributed](../../engines/table-engines/special/distributed.md) sends. This setting is applied at the ClickHouse server start and can’t be changed in a user session.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 16.
+
+## background_message_broker_schedule_pool_size {#background_message_broker_schedule_pool_size}
+
+Sets the number of threads performing background tasks for message streaming. This setting is applied at the ClickHouse server start and can’t be changed in a user session.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 16.
+
+**See Also**
+
+-   [Kafka](../../engines/table-engines/integrations/kafka.md#kafka) engine.
+-   [RabbitMQ](../../engines/table-engines/integrations/rabbitmq.md#rabbitmq-engine) engine.
+
+## validate_polygons {#validate_polygons}
+
+Enables or disables throwing an exception in the [pointInPolygon](../../sql-reference/functions/geo/index.md#pointinpolygon) function, if the polygon is self-intersecting or self-tangent.
+
+Possible values:
+
+- 0 — Throwing an exception is disabled. `pointInPolygon` accepts invalid polygons and returns possibly incorrect results for them.
+- 1 — Throwing an exception is enabled.
+
+Default value: 1.
+
+## transform_null_in {#transform_null_in}
+
+Enables equality of [NULL](../../sql-reference/syntax.md#null-literal) values for [IN](../../sql-reference/operators/in.md) operator.
+
+By default, `NULL` values can’t be compared because `NULL` means undefined value. Thus, comparison `expr = NULL` must always return `false`. With this setting `NULL = NULL` returns `true` for `IN` operator.
+
+Possible values:
+
+-   0 — Comparison of `NULL` values in `IN` operator returns `false`.
+-   1 — Comparison of `NULL` values in `IN` operator returns `true`.
+
+Default value: 0.
+
+**Example**
+
+Consider the `null_in` table:
+
+``` text
+┌──idx─┬─────i─┐
+│    1 │     1 │
+│    2 │  NULL │
+│    3 │     3 │
+└──────┴───────┘
+```
+
+Query:
+
+``` sql
+SELECT idx, i FROM null_in WHERE i IN (1, NULL) SETTINGS transform_null_in = 0;
+```
+
+Result:
+
+``` text
+┌──idx─┬────i─┐
+│    1 │    1 │
+└──────┴──────┘
+```
+
+Query:
+
+``` sql
+SELECT idx, i FROM null_in WHERE i IN (1, NULL) SETTINGS transform_null_in = 1;
+```
+
+Result:
+
+``` text
+┌──idx─┬─────i─┐
+│    1 │     1 │
+│    2 │  NULL │
+└──────┴───────┘
+```
+
+**See Also**
+
+-   [NULL Processing in IN Operators](../../sql-reference/operators/in.md#in-null-processing)
+
+## low_cardinality_max_dictionary_size {#low_cardinality_max_dictionary_size}
+
+Sets a maximum size in rows of a shared global dictionary for the [LowCardinality](../../sql-reference/data-types/lowcardinality.md) data type that can be written to a storage file system. This setting prevents issues with RAM in case of unlimited dictionary growth. All the data that can’t be encoded due to maximum dictionary size limitation ClickHouse writes in an ordinary method.
+
+Possible values:
+
+-   Any positive integer.
+
+Default value: 8192.
+
+## low_cardinality_use_single_dictionary_for_part {#low_cardinality_use_single_dictionary_for_part}
+
+Turns on or turns off using of single dictionary for the data part.
+
+By default, the ClickHouse server monitors the size of dictionaries and if a dictionary overflows then the server starts to write the next one. To prohibit creating several dictionaries set `low_cardinality_use_single_dictionary_for_part = 1`.
+
+Possible values:
+
+-   1 — Creating several dictionaries for the data part is prohibited.
+-   0 — Creating several dictionaries for the data part is not prohibited.
+
+Default value: 0.
+
+## low_cardinality_allow_in_native_format {#low_cardinality_allow_in_native_format}
+
+Allows or restricts using the [LowCardinality](../../sql-reference/data-types/lowcardinality.md) data type with the [Native](../../interfaces/formats.md#native) format.
+
+If usage of `LowCardinality` is restricted, ClickHouse server converts `LowCardinality`-columns to ordinary ones for `SELECT` queries, and convert ordinary columns to `LowCardinality`-columns for `INSERT` queries.
+
+This setting is required mainly for third-party clients which do not support `LowCardinality` data type.
+
+Possible values:
+
+-   1 — Usage of `LowCardinality` is not restricted.
+-   0 — Usage of `LowCardinality` is restricted.
+
+Default value: 1.
+
+## allow_suspicious_low_cardinality_types {#allow_suspicious_low_cardinality_types}
+
+Allows or restricts using [LowCardinality](../../sql-reference/data-types/lowcardinality.md) with data types with fixed size of 8 bytes or less: numeric data types and `FixedString(8_bytes_or_less)`.
+
+For small fixed values using of `LowCardinality` is usually inefficient, because ClickHouse stores a numeric index for each row. As a result:
+
+-   Disk space usage can rise.
+-   RAM consumption can be higher, depending on a dictionary size.
+-   Some functions can work slower due to extra coding/encoding operations.
+
+Merge times in [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md)-engine tables can grow due to all the reasons described above.
+
+Possible values:
+
+-   1 — Usage of `LowCardinality` is not restricted.
+-   0 — Usage of `LowCardinality` is restricted.
+
+Default value: 0.
+
+## min_insert_block_size_rows_for_materialized_views {#min-insert-block-size-rows-for-materialized-views}
+
+Sets the minimum number of rows in the block which can be inserted into a table by an `INSERT` query. Smaller-sized blocks are squashed into bigger ones. This setting is applied only for blocks inserted into [materialized view](../../sql-reference/statements/create/view.md). By adjusting this setting, you control blocks squashing while pushing to materialized view and avoid excessive memory usage.
+
+Possible values:
+
+-   Any positive integer.
+-   0 — Squashing disabled.
+
+Default value: 1048576.
+
+**See Also**
+
+-   [min_insert_block_size_rows](#min-insert-block-size-rows)
+
+## min_insert_block_size_bytes_for_materialized_views {#min-insert-block-size-bytes-for-materialized-views}
+
+Sets the minimum number of bytes in the block which can be inserted into a table by an `INSERT` query. Smaller-sized blocks are squashed into bigger ones. This setting is applied only for blocks inserted into [materialized view](../../sql-reference/statements/create/view.md). By adjusting this setting, you control blocks squashing while pushing to materialized view and avoid excessive memory usage.
+
+Possible values:
+
+-   Any positive integer.
+-   0 — Squashing disabled.
+
+Default value: 268435456.
+
+**See also**
+
+-   [min_insert_block_size_bytes](#min-insert-block-size-bytes)
+
+## output_format_pretty_grid_charset {#output-format-pretty-grid-charset}
+
+Allows changing a charset which is used for printing grids borders. Available charsets are UTF-8, ASCII.
+
+**Example**
+
+``` text
+SET output_format_pretty_grid_charset = 'UTF-8';
+SELECT * FROM a;
+┌─a─┐
+│ 1 │
+└───┘
+
+SET output_format_pretty_grid_charset = 'ASCII';
+SELECT * FROM a;
++-a-+
+| 1 |
++---+
+```
+## optimize_read_in_order {#optimize_read_in_order}
+
+Enables [ORDER BY](../../sql-reference/statements/select/order-by.md#optimize_read_in_order) optimization in [SELECT](../../sql-reference/statements/select/index.md) queries for reading data from [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables.
+
+Possible values:
+
+-   0 — `ORDER BY` optimization is disabled.
+-   1 — `ORDER BY` optimization is enabled.
+
+Default value: `1`.
+
+**See Also**
+
+-   [ORDER BY Clause](../../sql-reference/statements/select/order-by.md#optimize_read_in_order)
+
+## optimize_aggregation_in_order {#optimize_aggregation_in_order}
+
+Enables [GROUP BY](../../sql-reference/statements/select/group-by.md) optimization in [SELECT](../../sql-reference/statements/select/index.md) queries for aggregating data in corresponding order in [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables.
+
+Possible values:
+
+-   0 — `GROUP BY` optimization is disabled.
+-   1 — `GROUP BY` optimization is enabled.
+
+Default value: `0`.
+
+**See Also**
+
+-   [GROUP BY optimization](../../sql-reference/statements/select/group-by.md#aggregation-in-order)
+
+## mutations_sync {#mutations_sync}
+
+Allows to execute `ALTER TABLE ... UPDATE|DELETE` queries ([mutations](../../sql-reference/statements/alter/index.md#mutations)) synchronously.
+
+Possible values:
+
+-   0 - Mutations execute asynchronously.
+-   1 - The query waits for all mutations to complete on the current server.
+-   2 - The query waits for all mutations to complete on all replicas (if they exist).
+
+Default value: `0`.
+
+**See Also**
+
+-   [Synchronicity of ALTER Queries](../../sql-reference/statements/alter/index.md#synchronicity-of-alter-queries)
+-   [Mutations](../../sql-reference/statements/alter/index.md#mutations)
+
+## ttl_only_drop_parts {#ttl_only_drop_parts}
+
+Enables or disables complete dropping of data parts where all rows are expired in [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables.
+
+When `ttl_only_drop_parts` is disabled (by default), the ClickHouse server only deletes expired rows according to their TTL.
+
+When `ttl_only_drop_parts` is enabled, the ClickHouse server drops a whole part when all rows in it are expired.
+
+Dropping whole parts instead of partial cleaning TTL-d rows allows having shorter `merge_with_ttl_timeout` times and lower impact on system performance.
+
+Possible values:
+
+-   0 — The complete dropping of data parts is disabled.
+-   1 — The complete dropping of data parts is enabled.
+
+Default value: `0`.
+
+**See Also**
+
+-   [CREATE TABLE query clauses and settings](../../engines/table-engines/mergetree-family/mergetree.md#mergetree-query-clauses) (`merge_with_ttl_timeout` setting)
+-   [Table TTL](../../engines/table-engines/mergetree-family/mergetree.md#mergetree-table-ttl)
+
+## lock_acquire_timeout {#lock_acquire_timeout}
+
+Defines how many seconds a locking request waits before failing.
+
+Locking timeout is used to protect from deadlocks while executing read/write operations with tables. When the timeout expires and the locking request fails, the ClickHouse server throws an exception "Locking attempt timed out! Possible deadlock avoided. Client should retry." with error code `DEADLOCK_AVOIDED`.
+
+Possible values:
+
+-   Positive integer (in seconds).
+-   0 — No locking timeout.
+
+Default value: `120` seconds.
+
+## cast_keep_nullable {#cast_keep_nullable}
+
+Enables or disables keeping of the `Nullable` data type in [CAST](../../sql-reference/functions/type-conversion-functions.md#type_conversion_function-cast) operations.
+
+When the setting is enabled and the argument of `CAST` function is `Nullable`, the result is also transformed to `Nullable` type. When the setting is disabled, the result always has the destination type exactly.
+
+Possible values:
+
+-  0 — The `CAST` result has exactly the destination type specified.
+-  1 — If the argument type is `Nullable`, the `CAST` result is transformed to `Nullable(DestinationDataType)`.
+
+Default value: `0`.
+
+**Examples**
+
+The following query results in the destination data type exactly:
+
+```sql
+SET cast_keep_nullable = 0;
+SELECT CAST(toNullable(toInt32(0)) AS Int32) as x, toTypeName(x);
+```
+
+Result:
+
+```text
+┌─x─┬─toTypeName(CAST(toNullable(toInt32(0)), 'Int32'))─┐
+│ 0 │ Int32                                             │
+└───┴───────────────────────────────────────────────────┘
+```
+
+The following query results in the `Nullable` modification on the destination data type:
+
+```sql
+SET cast_keep_nullable = 1;
+SELECT CAST(toNullable(toInt32(0)) AS Int32) as x, toTypeName(x);
+```
+
+Result:
+
+```text
+┌─x─┬─toTypeName(CAST(toNullable(toInt32(0)), 'Int32'))─┐
+│ 0 │ Nullable(Int32)                                   │
+└───┴───────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [CAST](../../sql-reference/functions/type-conversion-functions.md#type_conversion_function-cast) function
+
+## output_format_pretty_max_value_width {#output_format_pretty_max_value_width}
+
+Limits the width of value displayed in [Pretty](../../interfaces/formats.md#pretty) formats. If the value width exceeds the limit, the value is cut.
+
+Possible values:
+
+-   Positive integer.
+-   0 — The value is cut completely.
+
+Default value: `10000` symbols.
+
+**Examples**
+
+Query:
+```sql
+SET output_format_pretty_max_value_width = 10;
+SELECT range(number) FROM system.numbers LIMIT 10 FORMAT PrettyCompactNoEscapes;
+```
+Result:
+```text
+┌─range(number)─┐
+│ []            │
+│ [0]           │
+│ [0,1]         │
+│ [0,1,2]       │
+│ [0,1,2,3]     │
+│ [0,1,2,3,4⋯   │
+│ [0,1,2,3,4⋯   │
+│ [0,1,2,3,4⋯   │
+│ [0,1,2,3,4⋯   │
+│ [0,1,2,3,4⋯   │
+└───────────────┘
+```
+
+Query with zero width:
+```sql
+SET output_format_pretty_max_value_width = 0;
+SELECT range(number) FROM system.numbers LIMIT 5 FORMAT PrettyCompactNoEscapes;
+```
+Result:
+```text
+┌─range(number)─┐
+│ ⋯             │
+│ ⋯             │
+│ ⋯             │
+│ ⋯             │
+│ ⋯             │
+└───────────────┘
+```
+
+## output_format_pretty_row_numbers {#output_format_pretty_row_numbers}
+
+Adds row numbers to output in the [Pretty](../../interfaces/formats.md#pretty) format.
+
+Possible values:
+
+-   0 — Output without row numbers.
+-   1 — Output with row numbers.
+
+Default value: `0`.
+
+**Example**
+
+Query:
+
+```sql
+SET output_format_pretty_row_numbers = 1;
+SELECT TOP 3 name, value FROM system.settings;
+```
+
+Result:
+```text
+   ┌─name────────────────────┬─value───┐
+1. │ min_compress_block_size │ 65536   │
+2. │ max_compress_block_size │ 1048576 │
+3. │ max_block_size          │ 65505   │
+   └─────────────────────────┴─────────┘
+```
+
+## system_events_show_zero_values {#system_events_show_zero_values}
+
+Allows to select zero-valued events from [`system.events`](../../operations/system-tables/events.md).
+
+Some monitoring systems require passing all the metrics values to them for each checkpoint, even if the metric value is zero.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: `0`.
+
+**Examples**
+
+Query
+
+```sql
+SELECT * FROM system.events WHERE event='QueryMemoryLimitExceeded';
+```
+
+Result
+
+```text
+Ok.
+```
+
+Query
+```sql
+SET system_events_show_zero_values = 1;
+SELECT * FROM system.events WHERE event='QueryMemoryLimitExceeded';
+```
+
+Result
+
+```text
+┌─event────────────────────┬─value─┬─description───────────────────────────────────────────┐
+│ QueryMemoryLimitExceeded │     0 │ Number of times when memory limit exceeded for query. │
+└──────────────────────────┴───────┴───────────────────────────────────────────────────────┘
+```
+
+## persistent {#persistent}
+
+Disables persistency for the [Set](../../engines/table-engines/special/set.md#set) and [Join](../../engines/table-engines/special/join.md#join) table engines.
+
+Reduces the I/O overhead. Suitable for scenarios that pursue performance and do not require persistence.
+
+Possible values:
+
+- 1 — Enabled.
+- 0 — Disabled.
+
+Default value: `1`.
+
+## format_csv_null_representation {#format_csv_null_representation}
+
+Defines the representation of `NULL` for [CSV](../../interfaces/formats.md#csv) output and input formats. User can set any string as a value, for example, `My NULL`.
+
+Default value: `\N`.
+
+**Examples**
+
+Query
+
+```sql
+SELECT * from csv_custom_null FORMAT CSV;
+```
+
+Result
+
+```text
+788
+\N
+\N
+```
+
+Query
+
+```sql
+SET format_csv_null_representation = 'My NULL';
+SELECT * FROM csv_custom_null FORMAT CSV;
+```
+
+Result
+
+```text
+788
+My NULL
+My NULL
+```
+
+## format_tsv_null_representation {#format_tsv_null_representation}
+
+Defines the representation of `NULL` for [TSV](../../interfaces/formats.md#tabseparated) output and input formats. User can set any string as a value, for example, `My NULL`.
+
+Default value: `\N`.
+
+**Examples**
+
+Query
+
+```sql
+SELECT * FROM tsv_custom_null FORMAT TSV;
+```
+
+Result
+
+```text
+788
+\N
+\N
+```
+
+Query
+
+```sql
+SET format_tsv_null_representation = 'My NULL';
+SELECT * FROM tsv_custom_null FORMAT TSV;
+```
+
+Result
+
+```text
+788
+My NULL
+My NULL
+```
+
+## output_format_json_array_of_rows {#output-format-json-array-of-rows}
+
+Enables the ability to output all rows as a JSON array in the [JSONEachRow](../../interfaces/formats.md#jsoneachrow) format.
+
+Possible values:
+
+-   1 — ClickHouse outputs all rows as an array, each row in the `JSONEachRow` format.
+-   0 — ClickHouse outputs each row separately in the `JSONEachRow` format.
+
+Default value: `0`.
+
+**Example of a query with the enabled setting**
+
+Query:
+
+```sql
+SET output_format_json_array_of_rows = 1;
+SELECT number FROM numbers(3) FORMAT JSONEachRow;
+```
+
+Result:
+
+```text
+[
+{"number":"0"},
+{"number":"1"},
+{"number":"2"}
+]
+```
+
+**Example of a query with the disabled setting**
+
+Query:
+
+```sql
+SET output_format_json_array_of_rows = 0;
+SELECT number FROM numbers(3) FORMAT JSONEachRow;
+```
+
+Result:
+
+```text
+{"number":"0"}
+{"number":"1"}
+{"number":"2"}
+```
+
+## allow_nullable_key {#allow-nullable-key}
+
+Allows using of the [Nullable](../../sql-reference/data-types/nullable.md#data_type-nullable)-typed values in a sorting and a primary key for [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md#table_engines-mergetree) tables.
+
+Possible values:
+
+- 1 — `Nullable`-type expressions are allowed in keys.
+- 0 — `Nullable`-type expressions are not allowed in keys.
+
+Default value: `0`.
+
+:::warning
+Nullable primary key usually indicates bad design. It is forbidden in almost all main stream DBMS. The feature is mainly for [AggregatingMergeTree](../../engines/table-engines/mergetree-family/aggregatingmergetree.md) and is not heavily tested. Use with care.
+:::
+
+:::warning
+Do not enable this feature in version `<= 21.8`. It's not properly implemented and may lead to server crash.
+:::
+
+## aggregate_functions_null_for_empty {#aggregate_functions_null_for_empty}
+
+Enables or disables rewriting all aggregate functions in a query, adding [-OrNull](../../sql-reference/aggregate-functions/combinators.md#agg-functions-combinator-ornull) suffix to them. Enable it for SQL standard compatibility.
+It is implemented via query rewrite (similar to [count_distinct_implementation](#settings-count_distinct_implementation) setting) to get consistent results for distributed queries.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 0.
+
+**Example**
+
+Consider the following query with aggregate functions:
+```sql
+SELECT SUM(-1), MAX(0) FROM system.one WHERE 0;
+```
+
+With `aggregate_functions_null_for_empty = 0` it would produce:
+```text
+┌─SUM(-1)─┬─MAX(0)─┐
+│       0 │      0 │
+└─────────┴────────┘
+```
+
+With `aggregate_functions_null_for_empty = 1` the result would be:
+```text
+┌─SUMOrNull(-1)─┬─MAXOrNull(0)─┐
+│          NULL │         NULL │
+└───────────────┴──────────────┘
+```
+
+## union_default_mode {#union-default-mode}
+
+Sets a mode for combining `SELECT` query results. The setting is only used when shared with [UNION](../../sql-reference/statements/select/union.md) without explicitly specifying the `UNION ALL` or `UNION DISTINCT`.
+
+Possible values:
+
+-   `'DISTINCT'` — ClickHouse outputs rows as a result of combining queries removing duplicate rows.
+-   `'ALL'` — ClickHouse outputs all rows as a result of combining queries including duplicate rows.
+-   `''` — ClickHouse generates an exception when used with `UNION`.
+
+Default value: `''`.
+
+See examples in [UNION](../../sql-reference/statements/select/union.md).
+
+## data_type_default_nullable {#data_type_default_nullable}
+
+Allows data types without explicit modifiers [NULL or NOT NULL](../../sql-reference/statements/create/table.md#null-modifiers) in column definition will be [Nullable](../../sql-reference/data-types/nullable.md#data_type-nullable).
+
+Possible values:
+
+- 1 — The data types in column definitions are set to `Nullable` by default.
+- 0 — The data types in column definitions are set to not `Nullable` by default.
+
+Default value: `0`.
+
+## execute_merges_on_single_replica_time_threshold {#execute-merges-on-single-replica-time-threshold}
+
+Enables special logic to perform merges on replicas.
+
+Possible values:
+
+-   Positive integer (in seconds).
+-   0 — Special merges logic is not used. Merges happen in the usual way on all the replicas.
+
+Default value: `0`.
+
+**Usage**
+
+Selects one replica to perform the merge on. Sets the time threshold from the start of the merge. Other replicas wait for the merge to finish, then download the result. If the time threshold passes and the selected replica does not perform the merge, then the merge is performed on other replicas as usual.
+
+High values for that threshold may lead to replication delays.
+
+It can be useful when merges are CPU bounded not IO bounded (performing heavy data compression, calculating aggregate functions or default expressions that require a large amount of calculations, or just very high number of tiny merges).
+
+## max_final_threads {#max-final-threads}
+
+Sets the maximum number of parallel threads for the `SELECT` query data read phase with the [FINAL](../../sql-reference/statements/select/from.md#select-from-final) modifier.
+
+Possible values:
+
+-   Positive integer.
+-   0 or 1 — Disabled. `SELECT` queries are executed in a single thread.
+
+Default value: `16`.
+
+## opentelemetry_start_trace_probability {#opentelemetry-start-trace-probability}
+
+Sets the probability that the ClickHouse can start a trace for executed queries (if no parent [trace context](https://www.w3.org/TR/trace-context/) is supplied).
+
+Possible values:
+
+-   0 — The trace for all executed queries is disabled (if no parent trace context is supplied).
+-   Positive floating-point number in the range [0..1]. For example, if the setting value is `0,5`, ClickHouse can start a trace on average for half of the queries.
+-   1 — The trace for all executed queries is enabled.
+
+Default value: `0`.
+
+## optimize_on_insert {#optimize-on-insert}
+
+Enables or disables data transformation before the insertion, as if merge was done on this block (according to table engine).
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: 1.
+
+**Example**
+
+The difference between enabled and disabled:
+
+Query:
+
+```sql
+SET optimize_on_insert = 1;
+
+CREATE TABLE test1 (`FirstTable` UInt32) ENGINE = ReplacingMergeTree ORDER BY FirstTable;
+
+INSERT INTO test1 SELECT number % 2 FROM numbers(5);
+
+SELECT * FROM test1;
+
+SET optimize_on_insert = 0;
+
+CREATE TABLE test2 (`SecondTable` UInt32) ENGINE = ReplacingMergeTree ORDER BY SecondTable;
+
+INSERT INTO test2 SELECT number % 2 FROM numbers(5);
+
+SELECT * FROM test2;
+```
+
+Result:
+
+``` text
+┌─FirstTable─┐
+│          0 │
+│          1 │
+└────────────┘
+
+┌─SecondTable─┐
+│           0 │
+│           0 │
+│           0 │
+│           1 │
+│           1 │
+└─────────────┘
+```
+
+Note that this setting influences [Materialized view](../../sql-reference/statements/create/view.md#materialized) and [MaterializedMySQL](../../engines/database-engines/materialized-mysql.md) behaviour.
+
+## engine_file_empty_if_not_exists {#engine-file-empty_if-not-exists}
+
+Allows to select data from a file engine table without file.
+
+Possible values:
+- 0 — `SELECT` throws exception.
+- 1 — `SELECT` returns empty result.
+
+Default value: `0`.
+
+## engine_file_truncate_on_insert {#engine-file-truncate-on-insert}
+
+Enables or disables truncate before insert in [File](../../engines/table-engines/special/file.md) engine tables.
+
+Possible values:
+- 0 — `INSERT` query appends new data to the end of the file.
+- 1 — `INSERT` replaces existing content of the file with the new data.
+
+Default value: `0`.
+
+## allow_experimental_geo_types {#allow-experimental-geo-types}
+
+Allows working with experimental [geo data types](../../sql-reference/data-types/geo.md).
+
+Possible values:
+
+-   0 — Working with geo data types is disabled.
+-   1 — Working with geo data types is enabled.
+
+Default value: `0`.
+
+## database_atomic_wait_for_drop_and_detach_synchronously {#database_atomic_wait_for_drop_and_detach_synchronously}
+
+Adds a modifier `SYNC` to all `DROP` and `DETACH` queries.
+
+Possible values:
+
+-   0 — Queries will be executed with delay.
+-   1 — Queries will be executed without delay.
+
+Default value: `0`.
+
+## show_table_uuid_in_table_create_query_if_not_nil {#show_table_uuid_in_table_create_query_if_not_nil}
+
+Sets the `SHOW TABLE` query display.
+
+Possible values:
+
+-   0 — The query will be displayed without table UUID.
+-   1 — The query will be displayed with table UUID.
+
+Default value: `0`.
+
+## allow_experimental_live_view {#allow-experimental-live-view}
+
+Allows creation of experimental [live views](../../sql-reference/statements/create/view.md#live-view).
+
+Possible values:
+
+-   0 — Working with live views is disabled.
+-   1 — Working with live views is enabled.
+
+Default value: `0`.
+
+## live_view_heartbeat_interval {#live-view-heartbeat-interval}
+
+Sets the heartbeat interval in seconds to indicate [live view](../../sql-reference/statements/create/view.md#live-view) is alive .
+
+Default value: `15`.
+
+## max_live_view_insert_blocks_before_refresh {#max-live-view-insert-blocks-before-refresh}
+
+Sets the maximum number of inserted blocks after which mergeable blocks are dropped and query for [live view](../../sql-reference/statements/create/view.md#live-view) is re-executed.
+
+Default value: `64`.
+
+## temporary_live_view_timeout {#temporary-live-view-timeout}
+
+Sets the interval in seconds after which [live view](../../sql-reference/statements/create/view.md#live-view) with timeout is deleted.
+
+Default value: `5`.
+
+## periodic_live_view_refresh {#periodic-live-view-refresh}
+
+Sets the interval in seconds after which periodically refreshed [live view](../../sql-reference/statements/create/view.md#live-view) is forced to refresh.
+
+Default value: `60`.
+
+## http_connection_timeout {#http_connection_timeout}
+
+HTTP connection timeout (in seconds).
+
+Possible values:
+
+-   Any positive integer.
+-   0 - Disabled (infinite timeout).
+
+Default value: 1.
+
+## http_send_timeout {#http_send_timeout}
+
+HTTP send timeout (in seconds).
+
+Possible values:
+
+-   Any positive integer.
+-   0 - Disabled (infinite timeout).
+
+Default value: 1800.
+
+## http_receive_timeout {#http_receive_timeout}
+
+HTTP receive timeout (in seconds).
+
+Possible values:
+
+-   Any positive integer.
+-   0 - Disabled (infinite timeout).
+
+Default value: 1800.
+
+## check_query_single_value_result {#check_query_single_value_result}
+
+Defines the level of detail for the [CHECK TABLE](../../sql-reference/statements/check-table.md#checking-mergetree-tables) query result for `MergeTree` family engines .
+
+Possible values:
+
+-   0 — the query shows a check status for every individual data part of a table.
+-   1 — the query shows the general table check status.
+
+Default value: `0`.
+
+## prefer_column_name_to_alias {#prefer-column-name-to-alias}
+
+Enables or disables using the original column names instead of aliases in query expressions and clauses. It especially matters when alias is the same as the column name, see [Expression Aliases](../../sql-reference/syntax.md#notes-on-usage). Enable this setting to make aliases syntax rules in ClickHouse more compatible with most other database engines.
+
+Possible values:
+
+- 0 — The column name is substituted with the alias.
+- 1 — The column name is not substituted with the alias.
+
+Default value: `0`.
+
+**Example**
+
+The difference between enabled and disabled:
+
+Query:
+
+```sql
+SET prefer_column_name_to_alias = 0;
+SELECT avg(number) AS number, max(number) FROM numbers(10);
+```
+
+Result:
+
+```text
+Received exception from server (version 21.5.1):
+Code: 184. DB::Exception: Received from localhost:9000. DB::Exception: Aggregate function avg(number) is found inside another aggregate function in query: While processing avg(number) AS number.
+```
+
+Query:
+
+```sql
+SET prefer_column_name_to_alias = 1;
+SELECT avg(number) AS number, max(number) FROM numbers(10);
+```
+
+Result:
+
+```text
+┌─number─┬─max(number)─┐
+│    4.5 │           9 │
+└────────┴─────────────┘
+```
+
+## limit {#limit}
+
+Sets the maximum number of rows to get from the query result. It adjusts the value set by the [LIMIT](../../sql-reference/statements/select/limit.md#limit-clause) clause, so that the limit, specified in the query, cannot exceed the limit, set by this setting.
+
+Possible values:
+
+-   0 — The number of rows is not limited.
+-   Positive integer.
+
+Default value: `0`.
+
+## offset {#offset}
+
+Sets the number of rows to skip before starting to return rows from the query. It adjusts the offset set by the [OFFSET](../../sql-reference/statements/select/offset.md#offset-fetch) clause, so that these two values are summarized.
+
+Possible values:
+
+-   0 — No rows are skipped .
+-   Positive integer.
+
+Default value: `0`.
+
+**Example**
+
+Input table:
+
+``` sql
+CREATE TABLE test (i UInt64) ENGINE = MergeTree() ORDER BY i;
+INSERT INTO test SELECT number FROM numbers(500);
+```
+
+Query:
+
+``` sql
+SET limit = 5;
+SET offset = 7;
+SELECT * FROM test LIMIT 10 OFFSET 100;
+```
+Result:
+
+``` text
+┌───i─┐
+│ 107 │
+│ 108 │
+│ 109 │
+└─────┘
+```
+
+## optimize_syntax_fuse_functions {#optimize_syntax_fuse_functions}
+
+Enables to fuse aggregate functions with identical argument. It rewrites query contains at least two aggregate functions from [sum](../../sql-reference/aggregate-functions/reference/sum.md#agg_function-sum), [count](../../sql-reference/aggregate-functions/reference/count.md#agg_function-count) or [avg](../../sql-reference/aggregate-functions/reference/avg.md#agg_function-avg) with identical argument to [sumCount](../../sql-reference/aggregate-functions/reference/sumcount.md#agg_function-sumCount).
+
+Possible values:
+
+-   0 — Functions with identical argument are not fused.
+-   1 — Functions with identical argument are fused.
+
+Default value: `0`.
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE fuse_tbl(a Int8, b Int8) Engine = Log;
+SET optimize_syntax_fuse_functions = 1;
+EXPLAIN SYNTAX SELECT sum(a), sum(b), count(b), avg(b) from fuse_tbl FORMAT TSV;
+```
+
+Result:
+
+``` text
+SELECT
+    sum(a),
+    sumCount(b).1,
+    sumCount(b).2,
+    (sumCount(b).1) / (sumCount(b).2)
+FROM fuse_tbl
+```
+
+## allow_experimental_database_replicated {#allow_experimental_database_replicated}
+
+Enables to create databases with [Replicated](../../engines/database-engines/replicated.md) engine.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled.
+
+Default value: `0`.
+
+## database_replicated_initial_query_timeout_sec {#database_replicated_initial_query_timeout_sec}
+
+Sets how long initial DDL query should wait for Replicated database to precess previous DDL queue entries in seconds.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Unlimited.
+
+Default value: `300`.
+
+## distributed_ddl_task_timeout {#distributed_ddl_task_timeout}
+
+Sets timeout for DDL query responses from all hosts in cluster. If a DDL request has not been performed on all hosts, a response will contain a timeout error and a request will be executed in an async mode. Negative value means infinite.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Async mode.
+-   Negative integer — infinite timeout.
+
+Default value: `180`.
+
+## distributed_ddl_output_mode {#distributed_ddl_output_mode}
+
+Sets format of distributed DDL query result.
+
+Possible values:
+
+-   `throw` — Returns result set with query execution status for all hosts where query is finished. If query has failed on some hosts, then it will rethrow the first exception. If query is not finished yet on some hosts and [distributed_ddl_task_timeout](#distributed_ddl_task_timeout) exceeded, then it throws `TIMEOUT_EXCEEDED` exception.
+-   `none` — Is similar to throw, but distributed DDL query returns no result set.
+-   `null_status_on_timeout` — Returns `NULL` as execution status in some rows of result set instead of throwing `TIMEOUT_EXCEEDED` if query is not finished on the corresponding hosts.
+-   `never_throw` — Do not throw `TIMEOUT_EXCEEDED` and do not rethrow exceptions if query has failed on some hosts.
+
+Default value: `throw`.
+
+## flatten_nested {#flatten-nested}
+
+Sets the data format of a [nested](../../sql-reference/data-types/nested-data-structures/nested.md) columns.
+
+Possible values:
+
+-   1 — Nested column is flattened to separate arrays.
+-   0 — Nested column stays a single array of tuples.
+
+Default value: `1`.
+
+**Usage**
+
+If the setting is set to `0`, it is possible to use an arbitrary level of nesting.
+
+**Examples**
+
+Query:
+
+``` sql
+SET flatten_nested = 1;
+CREATE TABLE t_nest (`n` Nested(a UInt32, b UInt32)) ENGINE = MergeTree ORDER BY tuple();
+
+SHOW CREATE TABLE t_nest;
+```
+
+Result:
+
+``` text
+┌─statement───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ CREATE TABLE default.t_nest
+(
+    `n.a` Array(UInt32),
+    `n.b` Array(UInt32)
+)
+ENGINE = MergeTree
+ORDER BY tuple()
+SETTINGS index_granularity = 8192 │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SET flatten_nested = 0;
+
+CREATE TABLE t_nest (`n` Nested(a UInt32, b UInt32)) ENGINE = MergeTree ORDER BY tuple();
+
+SHOW CREATE TABLE t_nest;
+```
+
+Result:
+
+``` text
+┌─statement──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ CREATE TABLE default.t_nest
+(
+    `n` Nested(a UInt32, b UInt32)
+)
+ENGINE = MergeTree
+ORDER BY tuple()
+SETTINGS index_granularity = 8192 │
+└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+## external_table_functions_use_nulls {#external-table-functions-use-nulls}
+
+Defines how [mysql](../../sql-reference/table-functions/mysql.md), [postgresql](../../sql-reference/table-functions/postgresql.md) and [odbc](../../sql-reference/table-functions/odbc.md)] table functions use Nullable columns.
+
+Possible values:
+
+-   0 — The table function explicitly uses Nullable columns.
+-   1 — The table function implicitly uses Nullable columns.
+
+Default value: `1`.
+
+**Usage**
+
+If the setting is set to `0`, the table function does not make Nullable columns and inserts default values instead of NULL. This is also applicable for NULL values inside arrays.
+
+## output_format_arrow_low_cardinality_as_dictionary {#output-format-arrow-low-cardinality-as-dictionary}
+
+Allows to convert the [LowCardinality](../../sql-reference/data-types/lowcardinality.md) type to the `DICTIONARY` type of the [Arrow](../../interfaces/formats.md#data-format-arrow) format for `SELECT` queries.
+
+Possible values:
+
+-   0 — The `LowCardinality` type is not converted to the `DICTIONARY` type.
+-   1 — The `LowCardinality` type is converted to the `DICTIONARY` type.
+
+Default value: `0`.
+
+## allow_experimental_projection_optimization {#allow-experimental-projection-optimization}
+
+Enables or disables [projection](../../engines/table-engines/mergetree-family/mergetree.md#projections) optimization when processing `SELECT` queries.
+
+Possible values:
+
+-   0 — Projection optimization disabled.
+-   1 — Projection optimization enabled.
+
+Default value: `0`.
+
+## force_optimize_projection {#force-optimize-projection}
+
+Enables or disables the obligatory use of [projections](../../engines/table-engines/mergetree-family/mergetree.md#projections) in `SELECT` queries, when projection optimization is enabled (see [allow_experimental_projection_optimization](#allow-experimental-projection-optimization) setting).
+
+Possible values:
+
+-   0 — Projection optimization is not obligatory.
+-   1 — Projection optimization is obligatory.
+
+Default value: `0`.
+
+## replication_alter_partitions_sync {#replication-alter-partitions-sync}
+
+Allows to set up waiting for actions to be executed on replicas by [ALTER](../../sql-reference/statements/alter/index.md), [OPTIMIZE](../../sql-reference/statements/optimize.md) or [TRUNCATE](../../sql-reference/statements/truncate.md) queries.
+
+Possible values:
+
+-   0 — Do not wait.
+-   1 — Wait for own execution.
+-   2 — Wait for everyone.
+
+Default value: `1`.
+
+## replication_wait_for_inactive_replica_timeout {#replication-wait-for-inactive-replica-timeout}
+
+Specifies how long (in seconds) to wait for inactive replicas to execute [ALTER](../../sql-reference/statements/alter/index.md), [OPTIMIZE](../../sql-reference/statements/optimize.md) or [TRUNCATE](../../sql-reference/statements/truncate.md) queries.
+
+Possible values:
+
+-   0 — Do not wait.
+-   Negative integer — Wait for unlimited time.
+-   Positive integer — The number of seconds to wait.
+
+Default value: `120` seconds.
+
+## regexp_max_matches_per_row {#regexp-max-matches-per-row}
+
+Sets the maximum number of matches for a single regular expression per row. Use it to protect against memory overload when using greedy regular expression in the [extractAllGroupsHorizontal](../../sql-reference/functions/string-search-functions.md#extractallgroups-horizontal) function.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `1000`.
+
+## http_max_single_read_retries {#http-max-single-read-retries}
+
+Sets the maximum number of retries during a single HTTP read.
+
+Possible values:
+
+-   Positive integer.
+
+Default value: `1024`.
+
+## log_queries_probability {#log-queries-probability}
+
+Allows a user to write to [query_log](../../operations/system-tables/query_log.md), [query_thread_log](../../operations/system-tables/query_thread_log.md), and [query_views_log](../../operations/system-tables/query_views_log.md) system tables only a sample of queries selected randomly with the specified probability. It helps to reduce the load with a large volume of queries in a second.
+
+Possible values:
+
+-   0 — Queries are not logged in the system tables.
+-   Positive floating-point number in the range [0..1]. For example, if the setting value is `0.5`, about half of the queries are logged in the system tables.
+-   1 — All queries are logged in the system tables.
+
+Default value: `1`.
+
+## short_circuit_function_evaluation {#short-circuit-function-evaluation}
+
+Allows calculating the [if](../../sql-reference/functions/conditional-functions.md#if), [multiIf](../../sql-reference/functions/conditional-functions.md#multiif), [and](../../sql-reference/functions/logical-functions.md#logical-and-function), and [or](../../sql-reference/functions/logical-functions.md#logical-or-function) functions according to a [short scheme](https://en.wikipedia.org/wiki/Short-circuit_evaluation). This helps optimize the execution of complex expressions in these functions and prevent possible exceptions (such as division by zero when it is not expected).
+
+Possible values:
+
+-   `enable` — Enables short-circuit function evaluation for functions that are suitable for it (can throw an exception or computationally heavy).
+-   `force_enable` — Enables short-circuit function evaluation for all functions.
+-   `disable` — Disables short-circuit function evaluation.
+
+Default value: `enable`.
+
+## max_hyperscan_regexp_length {#max-hyperscan-regexp-length}
+
+Defines the maximum length for each regular expression in the [hyperscan multi-match functions](../../sql-reference/functions/string-search-functions.md#multimatchanyhaystack-pattern1-pattern2-patternn).
+
+Possible values:
+
+-   Positive integer.
+-   0 - The length is not limited.
+
+Default value: `0`.
+
+**Example**
+
+Query:
+
+```sql
+SELECT multiMatchAny('abcd', ['ab','bcd','c','d']) SETTINGS max_hyperscan_regexp_length = 3;
+```
+
+Result:
+
+```text
+┌─multiMatchAny('abcd', ['ab', 'bcd', 'c', 'd'])─┐
+│                                              1 │
+└────────────────────────────────────────────────┘
+```
+
+Query:
+
+```sql
+SELECT multiMatchAny('abcd', ['ab','bcd','c','d']) SETTINGS max_hyperscan_regexp_length = 2;
+```
+
+Result:
+
+```text
+Exception: Regexp length too large.
+```
+
+**See Also**
+
+-   [max_hyperscan_regexp_total_length](#max-hyperscan-regexp-total-length)
+
+## max_hyperscan_regexp_total_length {#max-hyperscan-regexp-total-length}
+
+Sets the maximum length total of all regular expressions in each [hyperscan multi-match function](../../sql-reference/functions/string-search-functions.md#multimatchanyhaystack-pattern1-pattern2-patternn).
+
+Possible values:
+
+-   Positive integer.
+-   0 - The length is not limited.
+
+Default value: `0`.
+
+**Example**
+
+Query:
+
+```sql
+SELECT multiMatchAny('abcd', ['a','b','c','d']) SETTINGS max_hyperscan_regexp_total_length = 5;
+```
+
+Result:
+
+```text
+┌─multiMatchAny('abcd', ['a', 'b', 'c', 'd'])─┐
+│                                           1 │
+└─────────────────────────────────────────────┘
+```
+
+Query:
+
+```sql
+SELECT multiMatchAny('abcd', ['ab','bc','c','d']) SETTINGS max_hyperscan_regexp_total_length = 5;
+```
+
+Result:
+
+```text
+Exception: Total regexp lengths too large.
+```
+
+**See Also**
+
+-   [max_hyperscan_regexp_length](#max-hyperscan-regexp-length)
+
+## enable_positional_arguments {#enable-positional-arguments}
+
+Enables or disables supporting positional arguments for [GROUP BY](../../sql-reference/statements/select/group-by.md), [LIMIT BY](../../sql-reference/statements/select/limit-by.md), [ORDER BY](../../sql-reference/statements/select/order-by.md) statements. When you want to use column numbers instead of column names in these clauses, set `enable_positional_arguments = 1`.
+
+Possible values:
+
+-   0 — Positional arguments aren't supported.
+-   1 — Positional arguments are supported: column numbers can use instead of column names.
+
+Default value: `0`.
+
+**Example**
+
+Query:
+
+```sql
+CREATE TABLE positional_arguments(one Int, two Int, three Int) ENGINE=Memory();
+
+INSERT INTO positional_arguments VALUES (10, 20, 30), (20, 20, 10), (30, 10, 20);
+
+SET enable_positional_arguments = 1;
+
+SELECT * FROM positional_arguments ORDER BY 2,3;
+```
+
+Result:
+
+```text
+┌─one─┬─two─┬─three─┐
+│  30 │  10 │   20  │
+│  20 │  20 │   10  │
+│  10 │  20 │   30  │
+└─────┴─────┴───────┘
+```
+
+## optimize_move_to_prewhere {#optimize_move_to_prewhere}
+
+Enables or disables automatic [PREWHERE](../../sql-reference/statements/select/prewhere.md) optimization in [SELECT](../../sql-reference/statements/select/index.md) queries.
+
+Works only for [*MergeTree](../../engines/table-engines/mergetree-family/index.md) tables.
+
+Possible values:
+
+-   0 — Automatic `PREWHERE` optimization is disabled.
+-   1 — Automatic `PREWHERE` optimization is enabled.
+
+Default value: `1`.
+
+## optimize_move_to_prewhere_if_final {#optimize_move_to_prewhere_if_final}
+
+Enables or disables automatic [PREWHERE](../../sql-reference/statements/select/prewhere.md) optimization in [SELECT](../../sql-reference/statements/select/index.md) queries with [FINAL](../../sql-reference/statements/select/from.md#select-from-final) modifier.
+
+Works only for [*MergeTree](../../engines/table-engines/mergetree-family/index.md) tables.
+
+Possible values:
+
+-   0 — Automatic `PREWHERE` optimization in `SELECT` queries with `FINAL` modifier is disabled.
+-   1 — Automatic `PREWHERE` optimization in `SELECT` queries with `FINAL` modifier is enabled.
+
+Default value: `0`.
+
+**See Also**
+
+-   [optimize_move_to_prewhere](#optimize_move_to_prewhere) setting
+
+## describe_include_subcolumns {#describe_include_subcolumns}
+
+Enables describing subcolumns for a [DESCRIBE](../../sql-reference/statements/describe-table.md) query. For example, members of a [Tuple](../../sql-reference/data-types/tuple.md) or subcolumns of a [Map](../../sql-reference/data-types/map.md#map-subcolumns), [Nullable](../../sql-reference/data-types/nullable.md#finding-null) or an [Array](../../sql-reference/data-types/array.md#array-size) data type.
+
+Possible values:
+
+-   0 — Subcolumns are not included in `DESCRIBE` queries.
+-   1 — Subcolumns are included in `DESCRIBE` queries.
+
+Default value: `0`.
+
+**Example**
+
+See an example for the [DESCRIBE](../../sql-reference/statements/describe-table.md) statement.
+
+## async_insert {#async-insert}
+
+Enables or disables asynchronous inserts. This makes sense only for insertion over HTTP protocol. Note that deduplication isn't working for such inserts.
+
+If enabled, the data is combined into batches before the insertion into tables, so it is possible to do small and frequent insertions into ClickHouse (up to 15000 queries per second) without buffer tables.
+
+The data is inserted either after the [async_insert_max_data_size](#async-insert-max-data-size) is exceeded or after [async_insert_busy_timeout_ms](#async-insert-busy-timeout-ms) milliseconds since the first `INSERT` query. If the [async_insert_stale_timeout_ms](#async-insert-stale-timeout-ms) is set to a non-zero value, the data is inserted after `async_insert_stale_timeout_ms` milliseconds since the last query.
+
+If [wait_for_async_insert](#wait-for-async-insert) is enabled, every client will wait for the data to be processed and flushed to the table. Otherwise, the query would be processed almost instantly, even if the data is not inserted.
+
+Possible values:
+
+-   0 — Insertions are made synchronously, one after another.
+-   1 — Multiple asynchronous insertions enabled.
+
+Default value: `0`.
+
+## async_insert_threads {#async-insert-threads}
+
+The maximum number of threads for background data parsing and insertion.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Asynchronous insertions are disabled.
+
+Default value: `16`.
+
+## wait_for_async_insert {#wait-for-async-insert}
+
+Enables or disables waiting for processing of asynchronous insertion. If enabled, server will return `OK` only after the data is inserted. Otherwise, it will return `OK` even if the data wasn't inserted.
+
+Possible values:
+
+-   0 — Server returns `OK` even if the data is not yet inserted.
+-   1 — Server returns `OK` only after the data is inserted.
+
+Default value: `1`.
+
+## wait_for_async_insert_timeout {#wait-for-async-insert-timeout}
+
+The timeout in seconds for waiting for processing of asynchronous insertion.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Disabled.
+
+Default value: [lock_acquire_timeout](#lock_acquire_timeout).
+
+## async_insert_max_data_size {#async-insert-max-data-size}
+
+The maximum size of the unparsed data in bytes collected per query before being inserted.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Asynchronous insertions are disabled.
+
+Default value: `1000000`.
+
+## async_insert_busy_timeout_ms {#async-insert-busy-timeout-ms}
+
+The maximum timeout in milliseconds since the first `INSERT` query before inserting collected data.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Timeout disabled.
+
+Default value: `200`.
+
+## async_insert_stale_timeout_ms {#async-insert-stale-timeout-ms}
+
+The maximum timeout in milliseconds since the last `INSERT` query before dumping collected data. If enabled, the settings prolongs the [async_insert_busy_timeout_ms](#async-insert-busy-timeout-ms) with every `INSERT` query as long as [async_insert_max_data_size](#async-insert-max-data-size) is not exceeded.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Timeout disabled.
+
+Default value: `0`.
+
+## alter_partition_verbose_result {#alter-partition-verbose-result}
+
+Enables or disables the display of information about the parts to which the manipulation operations with partitions and parts have been successfully applied.
+Applicable to [ATTACH PARTITION|PART](../../sql-reference/statements/alter/partition.md#alter_attach-partition) and to [FREEZE PARTITION](../../sql-reference/statements/alter/partition.md#alter_freeze-partition).
+
+Possible values:
+
+-   0 — disable verbosity.
+-   1 — enable verbosity.
+
+Default value: `0`.
+
+**Example**
+
+```sql
+CREATE TABLE test(a Int64, d Date, s String) ENGINE = MergeTree PARTITION BY toYYYYMM(d) ORDER BY a;
+INSERT INTO test VALUES(1, '2021-01-01', '');
+INSERT INTO test VALUES(1, '2021-01-01', '');
+ALTER TABLE test DETACH PARTITION ID '202101';
+
+ALTER TABLE test ATTACH PARTITION ID '202101' SETTINGS alter_partition_verbose_result = 1;
+
+┌─command_type─────┬─partition_id─┬─part_name────┬─old_part_name─┐
+│ ATTACH PARTITION │ 202101       │ 202101_7_7_0 │ 202101_5_5_0  │
+│ ATTACH PARTITION │ 202101       │ 202101_8_8_0 │ 202101_6_6_0  │
+└──────────────────┴──────────────┴──────────────┴───────────────┘
+
+ALTER TABLE test FREEZE SETTINGS alter_partition_verbose_result = 1;
+
+┌─command_type─┬─partition_id─┬─part_name────┬─backup_name─┬─backup_path───────────────────┬─part_backup_path────────────────────────────────────────────┐
+│ FREEZE ALL   │ 202101       │ 202101_7_7_0 │ 8           │ /var/lib/clickhouse/shadow/8/ │ /var/lib/clickhouse/shadow/8/data/default/test/202101_7_7_0 │
+│ FREEZE ALL   │ 202101       │ 202101_8_8_0 │ 8           │ /var/lib/clickhouse/shadow/8/ │ /var/lib/clickhouse/shadow/8/data/default/test/202101_8_8_0 │
+└──────────────┴──────────────┴──────────────┴─────────────┴───────────────────────────────┴─────────────────────────────────────────────────────────────┘
+```
+
+## format_capn_proto_enum_comparising_mode {#format-capn-proto-enum-comparising-mode}
+
+Determines how to map ClickHouse `Enum` data type and [CapnProto](../../interfaces/formats.md#capnproto) `Enum` data type from schema.
+
+Possible values:
+
+-   `'by_values'` — Values in enums should be the same, names can be different.
+-   `'by_names'` — Names in enums should be the same, values can be different.
+-   `'by_name_case_insensitive'` — Names in enums should be the same case-insensitive, values can be different.
+
+Default value: `'by_values'`.
+
+## min_bytes_to_use_mmap_io {#min-bytes-to-use-mmap-io}
+
+This is an experimental setting. Sets the minimum amount of memory for reading large files without copying data from the kernel to userspace. Recommended threshold is about 64 MB, because [mmap/munmap](https://en.wikipedia.org/wiki/Mmap) is slow. It makes sense only for large files and helps only if data reside in the page cache.
+
+Possible values:
+
+-   Positive integer.
+-   0 — Big files read with only copying data from kernel to userspace.
+
+Default value: `0`.
+
+## format_custom_escaping_rule {#format-custom-escaping-rule}
+
+Sets the field escaping rule for [CustomSeparated](../../interfaces/formats.md#format-customseparated) data format.
+
+Possible values:
+
+-   `'Escaped'` — Similarly to [TSV](../../interfaces/formats.md#tabseparated).
+-   `'Quoted'` — Similarly to [Values](../../interfaces/formats.md#data-format-values).
+-   `'CSV'` — Similarly to [CSV](../../interfaces/formats.md#csv).
+-   `'JSON'` — Similarly to [JSONEachRow](../../interfaces/formats.md#jsoneachrow).
+-   `'XML'` — Similarly to [XML](../../interfaces/formats.md#xml).
+-   `'Raw'` — Extracts subpatterns as a whole, no escaping rules, similarly to [TSVRaw](../../interfaces/formats.md#tabseparatedraw).
+
+Default value: `'Escaped'`.
+
+## format_custom_field_delimiter {#format-custom-field-delimiter}
+
+Sets the character that is interpreted as a delimiter between the fields for [CustomSeparated](../../interfaces/formats.md#format-customseparated) data format.
+
+Default value: `'\t'`.
+
+## format_custom_row_before_delimiter {#format-custom-row-before-delimiter}
+
+Sets the character that is interpreted as a delimiter before the field of the first column for [CustomSeparated](../../interfaces/formats.md#format-customseparated) data format.
+
+Default value: `''`.
+
+## format_custom_row_after_delimiter {#format-custom-row-after-delimiter}
+
+Sets the character that is interpreted as a delimiter after the field of the last column for [CustomSeparated](../../interfaces/formats.md#format-customseparated) data format.
+
+Default value: `'\n'`.
+
+## format_custom_row_between_delimiter {#format-custom-row-between-delimiter}
+
+Sets the character that is interpreted as a delimiter between the rows for [CustomSeparated](../../interfaces/formats.md#format-customseparated) data format.
+
+Default value: `''`.
+
+## format_custom_result_before_delimiter {#format-custom-result-before-delimiter}
+
+Sets the character that is interpreted as a prefix before the result set for [CustomSeparated](../../interfaces/formats.md#format-customseparated) data format.
+
+Default value: `''`.
+
+## format_custom_result_after_delimiter {#format-custom-result-after-delimiter}
+
+Sets the character that is interpreted as a suffix after the result set for [CustomSeparated](../../interfaces/formats.md#format-customseparated) data format.
+
+Default value: `''`.
+
+## shutdown_wait_unfinished_queries
+
+Enables or disables waiting unfinished queries when shutdown server.
+
+Possible values:
+
+-   0 — Disabled.
+-   1 — Enabled. The wait time equal shutdown_wait_unfinished config.
+
+Default value: 0.
+
+## shutdown_wait_unfinished
+
+The waiting time in seconds for currently handled connections when shutdown server.
+
+Default Value: 5.
diff --git a/docs/en/reference/operations/ssl-zookeeper.md b/docs/en/reference/operations/ssl-zookeeper.md
new file mode 100644
index 00000000000..d6043d521e7
--- /dev/null
+++ b/docs/en/reference/operations/ssl-zookeeper.md
@@ -0,0 +1,73 @@
+---
+sidebar_position: 45
+sidebar_label: Secured Communication with Zookeeper
+---
+
+# Optional secured communication between ClickHouse and Zookeeper {#secured-communication-with-zookeeper}
+
+You should specify `ssl.keyStore.location`, `ssl.keyStore.password` and `ssl.trustStore.location`, `ssl.trustStore.password` for communication with ClickHouse client over SSL. These options are available from Zookeeper version 3.5.2.
+
+You can add `zookeeper.crt` to trusted certificates.
+
+``` bash
+sudo cp zookeeper.crt /usr/local/share/ca-certificates/zookeeper.crt
+sudo update-ca-certificates
+```
+
+Client section in `config.xml` will look like:
+
+``` xml
+<client>
+    <certificateFile>/etc/clickhouse-server/client.crt</certificateFile>
+    <privateKeyFile>/etc/clickhouse-server/client.key</privateKeyFile>
+    <loadDefaultCAFile>true</loadDefaultCAFile>
+    <cacheSessions>true</cacheSessions>
+    <disableProtocols>sslv2,sslv3</disableProtocols>
+    <preferServerCiphers>true</preferServerCiphers>
+    <invalidCertificateHandler>
+        <name>RejectCertificateHandler</name>
+    </invalidCertificateHandler>
+</client>
+```
+
+Add Zookeeper to ClickHouse config with some cluster and macros:
+
+``` xml
+<clickhouse>
+    <zookeeper>
+        <node>
+            <host>localhost</host>
+            <port>2281</port>
+            <secure>1</secure>
+        </node>
+    </zookeeper>
+</clickhouse>
+```
+
+Start `clickhouse-server`. In logs you should see:
+
+```text
+<Trace> ZooKeeper: initialized, hosts: secure://localhost:2281
+```
+
+Prefix `secure://` indicates that connection is secured by SSL.
+
+To ensure traffic is encrypted run `tcpdump` on secured port:
+
+```bash
+tcpdump -i any dst port 2281 -nnXS
+```
+
+And query in `clickhouse-client`:
+
+```sql
+SELECT * FROM system.zookeeper WHERE path = '/';
+```
+
+On unencrypted connection you will see in `tcpdump` output something like this:
+
+```text
+..../zookeeper/quota.
+```
+
+On encrypted connection you should not see this.
diff --git a/docs/en/reference/operations/storing-data.md b/docs/en/reference/operations/storing-data.md
new file mode 100644
index 00000000000..2162ae066dd
--- /dev/null
+++ b/docs/en/reference/operations/storing-data.md
@@ -0,0 +1,318 @@
+---
+sidebar_position: 68
+sidebar_label: External Disks for Storing Data
+---
+
+# External Disks for Storing Data {#external-disks}
+
+Data, processed in ClickHouse, is usually stored in the local file system — on the same machine with the ClickHouse server. That requires large-capacity disks, which can be expensive enough. To avoid that you can store the data remotely — on [Amazon S3](https://aws.amazon.com/s3/) disks or in the Hadoop Distributed File System ([HDFS](https://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-hdfs/HdfsDesign.html)). 
+
+To work with data stored on `Amazon S3` disks use [S3](../engines/table-engines/integrations/s3.md) table engine, and to work with data in the Hadoop Distributed File System — [HDFS](../engines/table-engines/integrations/hdfs.md) table engine.
+
+To load data from a web server with static files use a disk with type [web](#storing-data-on-webserver).
+
+## Zero-copy Replication {#zero-copy}
+
+ClickHouse supports zero-copy replication for `S3` and `HDFS` disks, which means that if the data is stored remotely on several machines and needs to be synchronized, then only the metadata is replicated (paths to the data parts), but not the data itself.
+
+## Configuring HDFS {#configuring-hdfs}
+
+[MergeTree](../engines/table-engines/mergetree-family/mergetree.md) and [Log](../engines/table-engines/log-family/log.md) family table engines can store data to HDFS using a disk with type `HDFS`.
+
+Configuration markup:
+
+``` xml
+<clickhouse>
+    <storage_configuration>
+        <disks>
+            <hdfs>
+                <type>hdfs</type>
+                <endpoint>hdfs://hdfs1:9000/clickhouse/</endpoint>
+            </hdfs>
+        </disks>
+        <policies>
+            <hdfs>
+                <volumes>
+                    <main>
+                        <disk>hdfs</disk>
+                    </main>
+                </volumes>
+            </hdfs>
+        </policies>
+    </storage_configuration>
+
+    <merge_tree>
+        <min_bytes_for_wide_part>0</min_bytes_for_wide_part>
+    </merge_tree>
+</clickhouse>
+```
+
+Required parameters:
+
+-   `endpoint` — HDFS endpoint URL in `path` format. Endpoint URL should contain a root path to store data.
+
+Optional parameters:
+
+-   `min_bytes_for_seek` — The minimal number of bytes to use seek operation instead of sequential read. Default value: `1 Mb`.
+
+## Using Virtual File System for Data Encryption {#encrypted-virtual-file-system}
+
+You can encrypt the data stored on [S3](../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-s3), or [HDFS](#configuring-hdfs) external disks, or on a local disk. To turn on the encryption mode, in the configuration file you must define a disk with the type `encrypted` and choose a disk on which the data will be saved. An `encrypted` disk ciphers all written files on the fly, and when you read files from an `encrypted` disk it deciphers them automatically. So you can work with an `encrypted` disk like with a normal one.
+
+Example of disk configuration:
+
+``` xml
+<disks>
+  <disk1>
+    <type>local</type>
+    <path>/path1/</path>
+  </disk1>
+  <disk2>
+    <type>encrypted</type>
+    <disk>disk1</disk>
+    <path>path2/</path>
+    <key>_16_ascii_chars_</key>
+  </disk2>
+</disks>
+```
+
+For example, when ClickHouse writes data from some table to a file `store/all_1_1_0/data.bin` to `disk1`, then in fact this file will be written to the physical disk along the path `/path1/store/all_1_1_0/data.bin`.
+
+When writing the same file to `disk2`, it will actually be written to the physical disk at the path `/path1/path2/store/all_1_1_0/data.bin` in encrypted mode.
+
+Required parameters:
+
+-   `type` — `encrypted`. Otherwise the encrypted disk is not created.
+-   `disk` — Type of disk for data storage.
+-   `key` — The key for encryption and decryption. Type: [Uint64](../sql-reference/data-types/int-uint.md). You can use `key_hex` parameter to encrypt in hexadecimal form.
+    You can specify multiple keys using the `id` attribute (see example above).
+
+Optional parameters:
+
+-   `path` — Path to the location on the disk where the data will be saved. If not specified, the data will be saved in the root directory.
+-   `current_key_id` — The key used for encryption. All the specified keys can be used for decryption, and you can always switch to another key while maintaining access to previously encrypted data.
+-   `algorithm` — [Algorithm](../sql-reference/statements/create/table.md#create-query-encryption-codecs) for encryption. Possible values: `AES_128_CTR`, `AES_192_CTR` or `AES_256_CTR`. Default value: `AES_128_CTR`. The key length depends on the algorithm: `AES_128_CTR` — 16 bytes, `AES_192_CTR` — 24 bytes, `AES_256_CTR` — 32 bytes.
+
+Example of disk configuration:
+
+``` xml
+<clickhouse>
+    <storage_configuration>
+        <disks>
+            <disk_s3>
+                <type>s3</type>
+                <endpoint>...
+            </disk_s3>
+            <disk_s3_encrypted>
+                <type>encrypted</type>
+                <disk>disk_s3</disk>
+                <algorithm>AES_128_CTR</algorithm>
+                <key_hex id="0">00112233445566778899aabbccddeeff</key_hex>
+                <key_hex id="1">ffeeddccbbaa99887766554433221100</key_hex>
+                <current_key_id>1</current_key_id>
+            </disk_s3_encrypted>
+        </disks>
+    </storage_configuration>
+</clickhouse>
+```
+
+## Storing Data on Web Server {#storing-data-on-webserver}
+
+There is a tool `clickhouse-static-files-uploader`, which prepares a data directory for a given table (`SELECT data_paths FROM system.tables WHERE name = 'table_name'`). For each table you need, you get a directory of files. These files can be uploaded to, for example, a web server with static files. After this preparation, you can load this table into any ClickHouse server via `DiskWeb`.
+
+This is a read-only disk. Its data is only read and never modified. A new table is loaded to this disk via `ATTACH TABLE` query (see example below). Local disk is not actually used, each `SELECT` query will result in a `http` request to fetch required data. All modification of the table data will result in an exception, i.e. the following types of queries are not allowed: [CREATE TABLE](../sql-reference/statements/create/table.md), [ALTER TABLE](../sql-reference/statements/alter/index.md), [RENAME TABLE](../sql-reference/statements/rename.md#misc_operations-rename_table), [DETACH TABLE](../sql-reference/statements/detach.md) and [TRUNCATE TABLE](../sql-reference/statements/truncate.md).
+
+Web server storage is supported only for the [MergeTree](../engines/table-engines/mergetree-family/mergetree.md) and [Log](../engines/table-engines/log-family/log.md) engine families. To access the data stored on a `web` disk, use the [storage_policy](../engines/table-engines/mergetree-family/mergetree.md#terms) setting when executing the query. For example, `ATTACH TABLE table_web UUID '{}' (id Int32) ENGINE = MergeTree() ORDER BY id SETTINGS storage_policy = 'web'`.
+
+A ready test case. You need to add this configuration to config:
+
+``` xml
+<clickhouse>
+    <storage_configuration>
+        <disks>
+            <web>
+                <type>web</type>
+                <endpoint>https://clickhouse-datasets.s3.yandex.net/disk-with-static-files-tests/test-hits/</endpoint>
+            </web>
+        </disks>
+        <policies>
+            <web>
+                <volumes>
+                    <main>
+                        <disk>web</disk>
+                    </main>
+                </volumes>
+            </web>
+        </policies>
+    </storage_configuration>
+</clickhouse>
+```
+
+And then execute this query:
+
+```sql
+ATTACH TABLE test_hits UUID '1ae36516-d62d-4218-9ae3-6516d62da218'
+(
+    WatchID UInt64,
+    JavaEnable UInt8,
+    Title String,
+    GoodEvent Int16,
+    EventTime DateTime,
+    EventDate Date,
+    CounterID UInt32,
+    ClientIP UInt32,
+    ClientIP6 FixedString(16),
+    RegionID UInt32,
+    UserID UInt64,
+    CounterClass Int8,
+    OS UInt8,
+    UserAgent UInt8,
+    URL String,
+    Referer String,
+    URLDomain String,
+    RefererDomain String,
+    Refresh UInt8,
+    IsRobot UInt8,
+    RefererCategories Array(UInt16),
+    URLCategories Array(UInt16),
+    URLRegions Array(UInt32),
+    RefererRegions Array(UInt32),
+    ResolutionWidth UInt16,
+    ResolutionHeight UInt16,
+    ResolutionDepth UInt8,
+    FlashMajor UInt8,
+    FlashMinor UInt8,
+    FlashMinor2 String,
+    NetMajor UInt8,
+    NetMinor UInt8,
+    UserAgentMajor UInt16,
+    UserAgentMinor FixedString(2),
+    CookieEnable UInt8,
+    JavascriptEnable UInt8,
+    IsMobile UInt8,
+    MobilePhone UInt8,
+    MobilePhoneModel String,
+    Params String,
+    IPNetworkID UInt32,
+    TraficSourceID Int8,
+    SearchEngineID UInt16,
+    SearchPhrase String,
+    AdvEngineID UInt8,
+    IsArtifical UInt8,
+    WindowClientWidth UInt16,
+    WindowClientHeight UInt16,
+    ClientTimeZone Int16,
+    ClientEventTime DateTime,
+    SilverlightVersion1 UInt8,
+    SilverlightVersion2 UInt8,
+    SilverlightVersion3 UInt32,
+    SilverlightVersion4 UInt16,
+    PageCharset String,
+    CodeVersion UInt32,
+    IsLink UInt8,
+    IsDownload UInt8,
+    IsNotBounce UInt8,
+    FUniqID UInt64,
+    HID UInt32,
+    IsOldCounter UInt8,
+    IsEvent UInt8,
+    IsParameter UInt8,
+    DontCountHits UInt8,
+    WithHash UInt8,
+    HitColor FixedString(1),
+    UTCEventTime DateTime,
+    Age UInt8,
+    Sex UInt8,
+    Income UInt8,
+    Interests UInt16,
+    Robotness UInt8,
+    GeneralInterests Array(UInt16),
+    RemoteIP UInt32,
+    RemoteIP6 FixedString(16),
+    WindowName Int32,
+    OpenerName Int32,
+    HistoryLength Int16,
+    BrowserLanguage FixedString(2),
+    BrowserCountry FixedString(2),
+    SocialNetwork String,
+    SocialAction String,
+    HTTPError UInt16,
+    SendTiming Int32,
+    DNSTiming Int32,
+    ConnectTiming Int32,
+    ResponseStartTiming Int32,
+    ResponseEndTiming Int32,
+    FetchTiming Int32,
+    RedirectTiming Int32,
+    DOMInteractiveTiming Int32,
+    DOMContentLoadedTiming Int32,
+    DOMCompleteTiming Int32,
+    LoadEventStartTiming Int32,
+    LoadEventEndTiming Int32,
+    NSToDOMContentLoadedTiming Int32,
+    FirstPaintTiming Int32,
+    RedirectCount Int8,
+    SocialSourceNetworkID UInt8,
+    SocialSourcePage String,
+    ParamPrice Int64,
+    ParamOrderID String,
+    ParamCurrency FixedString(3),
+    ParamCurrencyID UInt16,
+    GoalsReached Array(UInt32),
+    OpenstatServiceName String,
+    OpenstatCampaignID String,
+    OpenstatAdID String,
+    OpenstatSourceID String,
+    UTMSource String,
+    UTMMedium String,
+    UTMCampaign String,
+    UTMContent String,
+    UTMTerm String,
+    FromTag String,
+    HasGCLID UInt8,
+    RefererHash UInt64,
+    URLHash UInt64,
+    CLID UInt32,
+    YCLID UInt64,
+    ShareService String,
+    ShareURL String,
+    ShareTitle String,
+    ParsedParams Nested(
+        Key1 String,
+        Key2 String,
+        Key3 String,
+        Key4 String,
+        Key5 String,
+        ValueDouble Float64),
+    IslandID FixedString(16),
+    RequestNum UInt32,
+    RequestTry UInt8
+)
+ENGINE = MergeTree()
+PARTITION BY toYYYYMM(EventDate)
+ORDER BY (CounterID, EventDate, intHash32(UserID))
+SAMPLE BY intHash32(UserID)
+SETTINGS storage_policy='web';
+```
+
+Required parameters:
+
+-   `type` — `web`. Otherwise the disk is not created.
+-   `endpoint` — The endpoint URL in `path` format. Endpoint URL must contain a root path to store data, where they were uploaded.
+
+Optional parameters:
+
+-   `min_bytes_for_seek` — The minimal number of bytes to use seek operation instead of sequential read. Default value: `1` Mb.
+-   `remote_fs_read_backoff_threashold` — The maximum wait time when trying to read data for remote disk. Default value: `10000` seconds.
+-   `remote_fs_read_backoff_max_tries` — The maximum number of attempts to read with backoff. Default value: `5`.
+
+If a query fails with an exception `DB:Exception Unreachable URL`, then you can try to adjust the settings: [http_connection_timeout](../operations/settings/settings.md#http_connection_timeout), [http_receive_timeout](../operations/settings/settings.md#http_receive_timeout), [keep_alive_timeout](../operations/server-configuration-parameters/settings.md#keep-alive-timeout).
+
+To get files for upload run:
+`clickhouse static-files-disk-uploader --metadata-path <path> --output-dir <dir>` (`--metadata-path` can be found in query `SELECT data_paths FROM system.tables WHERE name = 'table_name'`).
+
+When loading files by `endpoint`, they must be loaded into `<endpoint>/store/` path, but config must contain only `endpoint`.
+
+If URL is not reachable on disk load when the server is starting up tables, then all errors are caught. If in this case there were errors, tables can be reloaded (become visible) via `DETACH TABLE table_name` -> `ATTACH TABLE table_name`. If metadata was successfully loaded at server startup, then tables are available straight away.
+
+Use [http_max_single_read_retries](../operations/settings/settings.md#http-max-single-read-retries) setting to limit the maximum number of retries during a single HTTP read.
diff --git a/docs/en/reference/operations/system-tables/asynchronous_metric_log.md b/docs/en/reference/operations/system-tables/asynchronous_metric_log.md
new file mode 100644
index 00000000000..2233406162b
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/asynchronous_metric_log.md
@@ -0,0 +1,39 @@
+# asynchronous_metric_log {#system-tables-async-log}
+
+Contains the historical values for `system.asynchronous_metrics`, which are saved once per minute. Enabled by default.
+
+Columns:
+
+-   `event_date` ([Date](../../sql-reference/data-types/date.md)) — Event date.
+-   `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Event time.
+-   `event_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Event time with microseconds resolution.
+-   `name` ([String](../../sql-reference/data-types/string.md)) — Metric name.
+-   `value` ([Float64](../../sql-reference/data-types/float.md)) — Metric value.
+
+**Example**
+
+``` sql
+SELECT * FROM system.asynchronous_metric_log LIMIT 10
+```
+
+``` text
+┌─event_date─┬──────────event_time─┬────event_time_microseconds─┬─name─────────────────────────────────────┬─────value─┐
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ CPUFrequencyMHz_0                        │    2120.9 │
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ jemalloc.arenas.all.pmuzzy               │       743 │
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ jemalloc.arenas.all.pdirty               │     26288 │
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ jemalloc.background_thread.run_intervals │         0 │
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ jemalloc.background_thread.num_runs      │         0 │
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ jemalloc.retained                        │  60694528 │
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ jemalloc.mapped                          │ 303161344 │
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ jemalloc.resident                        │ 260931584 │
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ jemalloc.metadata                        │  12079488 │
+│ 2020-09-05 │ 2020-09-05 15:56:30 │ 2020-09-05 15:56:30.025227 │ jemalloc.allocated                       │ 133756128 │
+└────────────┴─────────────────────┴────────────────────────────┴──────────────────────────────────────────┴───────────┘
+```
+
+**See Also**
+
+- [system.asynchronous_metrics](../system-tables/asynchronous_metrics.md) — Contains metrics, calculated periodically in the background.
+- [system.metric_log](../system-tables/metric_log.md) — Contains history of metrics values from tables `system.metrics` and `system.events`, periodically flushed to disk.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/asynchronous_metric_log) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/asynchronous_metrics.md b/docs/en/reference/operations/system-tables/asynchronous_metrics.md
new file mode 100644
index 00000000000..162048b06ee
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/asynchronous_metrics.md
@@ -0,0 +1,38 @@
+# asynchronous_metrics {#system_tables-asynchronous_metrics}
+
+Contains metrics that are calculated periodically in the background. For example, the amount of RAM in use.
+
+Columns:
+
+-   `metric` ([String](../../sql-reference/data-types/string.md)) — Metric name.
+-   `value` ([Float64](../../sql-reference/data-types/float.md)) — Metric value.
+
+**Example**
+
+``` sql
+SELECT * FROM system.asynchronous_metrics LIMIT 10
+```
+
+``` text
+┌─metric──────────────────────────────────┬──────value─┐
+│ jemalloc.background_thread.run_interval │          0 │
+│ jemalloc.background_thread.num_runs     │          0 │
+│ jemalloc.background_thread.num_threads  │          0 │
+│ jemalloc.retained                       │  422551552 │
+│ jemalloc.mapped                         │ 1682989056 │
+│ jemalloc.resident                       │ 1656446976 │
+│ jemalloc.metadata_thp                   │          0 │
+│ jemalloc.metadata                       │   10226856 │
+│ UncompressedCacheCells                  │          0 │
+│ MarkCacheFiles                          │          0 │
+└─────────────────────────────────────────┴────────────┘
+```
+
+**See Also**
+
+-   [Monitoring](../../operations/monitoring.md) — Base concepts of ClickHouse monitoring.
+-   [system.metrics](../../operations/system-tables/metrics.md#system_tables-metrics) — Contains instantly calculated metrics.
+-   [system.events](../../operations/system-tables/events.md#system_tables-events) — Contains a number of events that have occurred.
+-   [system.metric_log](../../operations/system-tables/metric_log.md#system_tables-metric_log) — Contains a history of metrics values from tables `system.metrics` and `system.events`.
+
+ [Original article](https://clickhouse.com/docs/en/operations/system-tables/asynchronous_metrics) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/clusters.md b/docs/en/reference/operations/system-tables/clusters.md
new file mode 100644
index 00000000000..776c90b9936
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/clusters.md
@@ -0,0 +1,71 @@
+# clusters {#system-clusters}
+
+Contains information about clusters available in the config file and the servers in them.
+
+Columns:
+
+-   `cluster` ([String](../../sql-reference/data-types/string.md)) — The cluster name.
+-   `shard_num` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The shard number in the cluster, starting from 1.
+-   `shard_weight` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The relative weight of the shard when writing data.
+-   `replica_num` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The replica number in the shard, starting from 1.
+-   `host_name` ([String](../../sql-reference/data-types/string.md)) — The host name, as specified in the config.
+-   `host_address` ([String](../../sql-reference/data-types/string.md)) — The host IP address obtained from DNS.
+-   `port` ([UInt16](../../sql-reference/data-types/int-uint.md)) — The port to use for connecting to the server.
+-   `is_local` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag that indicates whether the host is local.
+-   `user` ([String](../../sql-reference/data-types/string.md)) — The name of the user for connecting to the server.
+-   `default_database` ([String](../../sql-reference/data-types/string.md)) — The default database name.
+-   `errors_count` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The number of times this host failed to reach replica.
+-   `slowdowns_count` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The number of slowdowns that led to changing replica when establishing a connection with hedged requests.
+-   `estimated_recovery_time` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Seconds remaining until the replica error count is zeroed and it is considered to be back to normal.
+
+**Example**
+
+Query:
+
+```sql
+SELECT * FROM system.clusters LIMIT 2 FORMAT Vertical;
+```
+
+Result:
+
+```text
+Row 1:
+──────
+cluster:                 test_cluster_two_shards
+shard_num:               1
+shard_weight:            1
+replica_num:             1
+host_name:               127.0.0.1
+host_address:            127.0.0.1
+port:                    9000
+is_local:                1
+user:                    default
+default_database:
+errors_count:            0
+slowdowns_count:         0
+estimated_recovery_time: 0
+
+Row 2:
+──────
+cluster:                 test_cluster_two_shards
+shard_num:               2
+shard_weight:            1
+replica_num:             1
+host_name:               127.0.0.2
+host_address:            127.0.0.2
+port:                    9000
+is_local:                0
+user:                    default
+default_database:
+errors_count:            0
+slowdowns_count:         0
+estimated_recovery_time: 0
+```
+
+**See Also**
+
+-   [Table engine Distributed](../../engines/table-engines/special/distributed.md)
+-   [distributed_replica_error_cap setting](../../operations/settings/settings.md#settings-distributed_replica_error_cap)
+-   [distributed_replica_error_half_life setting](../../operations/settings/settings.md#settings-distributed_replica_error_half_life)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/clusters) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/columns.md b/docs/en/reference/operations/system-tables/columns.md
new file mode 100644
index 00000000000..dd5674fe5b1
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/columns.md
@@ -0,0 +1,89 @@
+# columns {#system-columns}
+
+Contains information about columns in all the tables.
+
+You can use this table to get information similar to the [DESCRIBE TABLE](../../sql-reference/statements/misc.md#misc-describe-table) query, but for multiple tables at once.
+
+Columns from [temporary tables](../../sql-reference/statements/create/table.md#temporary-tables) are visible in the `system.columns` only in those session where they have been created. They are shown with the empty `database` field.
+
+The `system.columns` table contains the following columns (the column type is shown in brackets):
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) — Database name.
+-   `table` ([String](../../sql-reference/data-types/string.md)) — Table name.
+-   `name` ([String](../../sql-reference/data-types/string.md)) — Column name.
+-   `type` ([String](../../sql-reference/data-types/string.md)) — Column type.
+-   `position` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Ordinal position of a column in a table starting with 1.
+-   `default_kind` ([String](../../sql-reference/data-types/string.md)) — Expression type (`DEFAULT`, `MATERIALIZED`, `ALIAS`) for the default value, or an empty string if it is not defined.
+-   `default_expression` ([String](../../sql-reference/data-types/string.md)) — Expression for the default value, or an empty string if it is not defined.
+-   `data_compressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The size of compressed data, in bytes.
+-   `data_uncompressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The size of decompressed data, in bytes.
+-   `marks_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The size of marks, in bytes.
+-   `comment` ([String](../../sql-reference/data-types/string.md)) — Comment on the column, or an empty string if it is not defined.
+-   `is_in_partition_key` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag that indicates whether the column is in the partition expression.
+-   `is_in_sorting_key` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag that indicates whether the column is in the sorting key expression.
+-   `is_in_primary_key` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag that indicates whether the column is in the primary key expression.
+-   `is_in_sampling_key` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag that indicates whether the column is in the sampling key expression.
+-   `compression_codec` ([String](../../sql-reference/data-types/string.md)) — Compression codec name.
+-   `character_octet_length` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum length in bytes for binary data, character data, or text data and images. In ClickHouse makes sense only for `FixedString` data type. Otherwise, the `NULL` value is returned.
+-   `numeric_precision` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Accuracy of approximate numeric data, exact numeric data, integer data, or monetary data. In ClickHouse it is bitness for integer types and decimal precision for `Decimal` types. Otherwise, the `NULL` value is returned.
+-   `numeric_precision_radix` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The base of the number system is the accuracy of approximate numeric data, exact numeric data, integer data or monetary data. In ClickHouse it's 2 for integer types and 10 for `Decimal` types. Otherwise, the `NULL` value is returned.
+-   `numeric_scale` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The scale of approximate numeric data, exact numeric data, integer data, or monetary data. In ClickHouse makes sense only for `Decimal` types. Otherwise, the `NULL` value is returned.
+-   `datetime_precision` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Decimal precision of `DateTime64` data type. For other data types, the `NULL` value is returned.
+
+**Example**
+
+```sql
+SELECT * FROM system.columns LIMIT 2 FORMAT Vertical;
+```
+
+```text
+Row 1:
+──────
+database:                INFORMATION_SCHEMA
+table:                   COLUMNS
+name:                    table_catalog
+type:                    String
+position:                1
+default_kind:
+default_expression:
+data_compressed_bytes:   0
+data_uncompressed_bytes: 0
+marks_bytes:             0
+comment:
+is_in_partition_key:     0
+is_in_sorting_key:       0
+is_in_primary_key:       0
+is_in_sampling_key:      0
+compression_codec:
+character_octet_length:  ᴺᵁᴸᴸ
+numeric_precision:       ᴺᵁᴸᴸ
+numeric_precision_radix: ᴺᵁᴸᴸ
+numeric_scale:           ᴺᵁᴸᴸ
+datetime_precision:      ᴺᵁᴸᴸ
+
+Row 2:
+──────
+database:                INFORMATION_SCHEMA
+table:                   COLUMNS
+name:                    table_schema
+type:                    String
+position:                2
+default_kind:
+default_expression:
+data_compressed_bytes:   0
+data_uncompressed_bytes: 0
+marks_bytes:             0
+comment:
+is_in_partition_key:     0
+is_in_sorting_key:       0
+is_in_primary_key:       0
+is_in_sampling_key:      0
+compression_codec:
+character_octet_length:  ᴺᵁᴸᴸ
+numeric_precision:       ᴺᵁᴸᴸ
+numeric_precision_radix: ᴺᵁᴸᴸ
+numeric_scale:           ᴺᵁᴸᴸ
+datetime_precision:      ᴺᵁᴸᴸ
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/columns) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/contributors.md b/docs/en/reference/operations/system-tables/contributors.md
new file mode 100644
index 00000000000..3b76684b44b
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/contributors.md
@@ -0,0 +1,41 @@
+# contributors {#system-contributors}
+
+Contains information about contributors. The order is random at query execution time.
+
+Columns:
+
+-   `name` (String) — Contributor (author) name from git log.
+
+**Example**
+
+``` sql
+SELECT * FROM system.contributors LIMIT 10
+```
+
+``` text
+┌─name─────────────┐
+│ Olga Khvostikova │
+│ Max Vetrov       │
+│ LiuYangkuan      │
+│ svladykin        │
+│ zamulla          │
+│ Šimon Podlipský  │
+│ BayoNet          │
+│ Ilya Khomutov    │
+│ Amy Krishnevsky  │
+│ Loud_Scream      │
+└──────────────────┘
+```
+
+To find out yourself in the table, use a query:
+
+``` sql
+SELECT * FROM system.contributors WHERE name = 'Olga Khvostikova'
+```
+
+``` text
+┌─name─────────────┐
+│ Olga Khvostikova │
+└──────────────────┘
+```
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/contributors) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/crash-log.md b/docs/en/reference/operations/system-tables/crash-log.md
new file mode 100644
index 00000000000..be85cb78c9f
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/crash-log.md
@@ -0,0 +1,48 @@
+# crash_log {#system-tables_crash_log}
+
+Contains information about stack traces for fatal errors. The table does not exist in the database by default, it is created only when fatal errors occur.
+
+Columns:
+
+-   `event_date` ([Datetime](../../sql-reference/data-types/datetime.md)) — Date of the event.
+-   `event_time` ([Datetime](../../sql-reference/data-types/datetime.md)) — Time of the event.
+-   `timestamp_ns` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Timestamp of the event with nanoseconds.
+-   `signal` ([Int32](../../sql-reference/data-types/int-uint.md)) — Signal number.
+-   `thread_id` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Thread ID.
+-   `query_id` ([String](../../sql-reference/data-types/string.md)) — Query ID.
+-   `trace` ([Array](../../sql-reference/data-types/array.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Stack trace at the moment of crash. Each element is a virtual memory address inside ClickHouse server process.
+-   `trace_full` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Stack trace at the moment of crash. Each element contains a called method inside ClickHouse server process.
+-   `version` ([String](../../sql-reference/data-types/string.md)) — ClickHouse server version.
+-   `revision` ([UInt32](../../sql-reference/data-types/int-uint.md)) — ClickHouse server revision.
+-   `build_id` ([String](../../sql-reference/data-types/string.md)) — BuildID that is generated by compiler.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT * FROM system.crash_log ORDER BY event_time DESC LIMIT 1;
+```
+
+Result (not full):
+
+``` text
+Row 1:
+──────
+event_date:   2020-10-14
+event_time:   2020-10-14 15:47:40
+timestamp_ns: 1602679660271312710
+signal:       11
+thread_id:    23624
+query_id:     428aab7c-8f5c-44e9-9607-d16b44467e69
+trace:        [188531193,...]
+trace_full:   ['3. DB::(anonymous namespace)::FunctionFormatReadableTimeDelta::executeImpl(std::__1::vector<DB::ColumnWithTypeAndName, std::__1::allocator<DB::ColumnWithTypeAndName> >&, std::__1::vector<unsigned long, std::__1::allocator<unsigned long> > const&, unsigned long, unsigned long) const @ 0xb3cc1f9 in /home/username/work/ClickHouse/build/programs/clickhouse',...]
+version:      ClickHouse 20.11.1.1
+revision:     54442
+build_id:
+```
+
+**See also**
+-   [trace_log](../../operations/system-tables/trace_log.md) system table
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/crash-log)
diff --git a/docs/en/reference/operations/system-tables/current-roles.md b/docs/en/reference/operations/system-tables/current-roles.md
new file mode 100644
index 00000000000..81d4fad24a8
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/current-roles.md
@@ -0,0 +1,11 @@
+# current_roles {#system_tables-current_roles}
+
+Contains active roles of a current user. `SET ROLE` changes the contents of this table.
+
+Columns:
+
+ - `role_name` ([String](../../sql-reference/data-types/string.md))) — Role name.
+ - `with_admin_option` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Flag that shows whether `current_role` is a role with `ADMIN OPTION` privilege.
+ - `is_default` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Flag that shows whether `current_role` is a default role.
+
+ [Original article](https://clickhouse.com/docs/en/operations/system-tables/current-roles) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/data_skipping_indices.md b/docs/en/reference/operations/system-tables/data_skipping_indices.md
new file mode 100644
index 00000000000..71dfb046dbb
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/data_skipping_indices.md
@@ -0,0 +1,47 @@
+# data_skipping_indices {#system-data-skipping-indices}
+
+Contains information about existing data skipping indices in all the tables.
+
+Columns:
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) — Database name.
+-   `table` ([String](../../sql-reference/data-types/string.md)) — Table name.
+-   `name` ([String](../../sql-reference/data-types/string.md)) — Index name.
+-   `type` ([String](../../sql-reference/data-types/string.md)) — Index type.
+-   `expr` ([String](../../sql-reference/data-types/string.md)) — Expression for the index calculation.
+-   `granularity` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The number of granules in the block.
+-   `data_compressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The size of compressed data, in bytes.
+-   `data_uncompressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The size of decompressed data, in bytes.
+-   `marks_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The size of marks, in bytes.
+
+**Example**
+
+```sql
+SELECT * FROM system.data_skipping_indices LIMIT 2 FORMAT Vertical;
+```
+
+```text
+Row 1:
+──────
+database:    default
+table:       user_actions
+name:        clicks_idx
+type:        minmax
+expr:        clicks
+granularity: 1
+data_compressed_bytes:   58
+data_uncompressed_bytes: 6
+marks:                   48
+
+Row 2:
+──────
+database:    default
+table:       users
+name:        contacts_null_idx
+type:        minmax
+expr:        assumeNotNull(contacts_null)
+granularity: 1
+data_compressed_bytes:   58
+data_uncompressed_bytes: 6
+marks:                   48
+```
diff --git a/docs/en/reference/operations/system-tables/data_type_families.md b/docs/en/reference/operations/system-tables/data_type_families.md
new file mode 100644
index 00000000000..2e5e7b74c66
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/data_type_families.md
@@ -0,0 +1,36 @@
+# data_type_families {#system_tables-data_type_families}
+
+Contains information about supported [data types](../../sql-reference/data-types/index.md).
+
+Columns:
+
+-   `name` ([String](../../sql-reference/data-types/string.md)) — Data type name.
+-   `case_insensitive` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Property that shows whether you can use a data type name in a query in case insensitive manner or not. For example, `Date` and `date` are both valid.
+-   `alias_to` ([String](../../sql-reference/data-types/string.md)) — Data type name for which `name` is an alias.
+
+**Example**
+
+``` sql
+SELECT * FROM system.data_type_families WHERE alias_to = 'String'
+```
+
+``` text
+┌─name───────┬─case_insensitive─┬─alias_to─┐
+│ LONGBLOB   │                1 │ String   │
+│ LONGTEXT   │                1 │ String   │
+│ TINYTEXT   │                1 │ String   │
+│ TEXT       │                1 │ String   │
+│ VARCHAR    │                1 │ String   │
+│ MEDIUMBLOB │                1 │ String   │
+│ BLOB       │                1 │ String   │
+│ TINYBLOB   │                1 │ String   │
+│ CHAR       │                1 │ String   │
+│ MEDIUMTEXT │                1 │ String   │
+└────────────┴──────────────────┴──────────┘
+```
+
+**See Also**
+
+-   [Syntax](../../sql-reference/syntax.md) — Information about supported syntax.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/data_type_families) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/databases.md b/docs/en/reference/operations/system-tables/databases.md
new file mode 100644
index 00000000000..7245ecdcdec
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/databases.md
@@ -0,0 +1,37 @@
+# databases {#system-databases}
+
+Contains information about the databases that are available to the current user.
+
+Columns:
+
+-   `name` ([String](../../sql-reference/data-types/string.md)) — Database name.
+-   `engine` ([String](../../sql-reference/data-types/string.md)) — [Database engine](../../engines/database-engines/index.md).
+-   `data_path` ([String](../../sql-reference/data-types/string.md)) — Data path.
+-   `metadata_path` ([String](../../sql-reference/data-types/enum.md)) — Metadata path.
+-   `uuid` ([UUID](../../sql-reference/data-types/uuid.md)) — Database UUID.
+-   `comment` ([String](../../sql-reference/data-types/enum.md)) — Database comment.
+
+The `name` column from this system table is used for implementing the `SHOW DATABASES` query.
+
+**Example**
+
+Create a database.
+
+``` sql
+CREATE DATABASE test;
+```
+
+Check all of the available databases to the user.
+
+``` sql
+SELECT * FROM system.databases;
+```
+
+``` text
+┌─name───────────────┬─engine─┬─data_path──────────────────┬─metadata_path───────────────────────────────────────────────────────┬─uuid─────────────────────────────────┬─comment─┐
+│ INFORMATION_SCHEMA │ Memory │ /var/lib/clickhouse/       │                                                                     │ 00000000-0000-0000-0000-000000000000 │         │
+│ default            │ Atomic │ /var/lib/clickhouse/store/ │ /var/lib/clickhouse/store/d31/d317b4bd-3595-4386-81ee-c2334694128a/ │ 24363899-31d7-42a0-a436-389931d752a0 │         │
+│ information_schema │ Memory │ /var/lib/clickhouse/       │                                                                     │ 00000000-0000-0000-0000-000000000000 │         │
+│ system             │ Atomic │ /var/lib/clickhouse/store/ │ /var/lib/clickhouse/store/1d1/1d1c869d-e465-4b1b-a51f-be033436ebf9/ │ 03e9f3d1-cc88-4a49-83e9-f3d1cc881a49 │         │
+└────────────────────┴────────┴────────────────────────────┴─────────────────────────────────────────────────────────────────────┴──────────────────────────────────────┴─────────┘
+```
diff --git a/docs/en/reference/operations/system-tables/detached_parts.md b/docs/en/reference/operations/system-tables/detached_parts.md
new file mode 100644
index 00000000000..2fe354a4471
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/detached_parts.md
@@ -0,0 +1,11 @@
+# detached_parts {#system_tables-detached_parts}
+
+Contains information about detached parts of [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables. The `reason` column specifies why the part was detached.
+
+For user-detached parts, the reason is empty. Such parts can be attached with [ALTER TABLE ATTACH PARTITION\|PART](../../sql-reference/statements/alter/partition.md#alter_attach-partition) command.
+
+For the description of other columns, see [system.parts](../../operations/system-tables/parts.md#system_tables-parts).
+
+If part name is invalid, values of some columns may be `NULL`. Such parts can be deleted with [ALTER TABLE DROP DETACHED PART](../../sql-reference/statements/alter/partition.md#alter_drop-detached).
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/detached_parts) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/dictionaries.md b/docs/en/reference/operations/system-tables/dictionaries.md
new file mode 100644
index 00000000000..c41d506ff0a
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/dictionaries.md
@@ -0,0 +1,88 @@
+# dictionaries {#system_tables-dictionaries}
+
+Contains information about [external dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md).
+
+Columns:
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) — Name of the database containing the dictionary created by DDL query. Empty string for other dictionaries.
+-   `name` ([String](../../sql-reference/data-types/string.md)) — [Dictionary name](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict.md).
+-   `uuid` ([UUID](../../sql-reference/data-types/uuid.md)) — Dictionary UUID.
+-   `status` ([Enum8](../../sql-reference/data-types/enum.md)) — Dictionary status. Possible values:
+    -   `NOT_LOADED` — Dictionary was not loaded because it was not used.
+    -   `LOADED` — Dictionary loaded successfully.
+    -   `FAILED` — Unable to load the dictionary as a result of an error.
+    -   `LOADING` — Dictionary is loading now.
+    -   `LOADED_AND_RELOADING` — Dictionary is loaded successfully, and is being reloaded right now (frequent reasons: [SYSTEM RELOAD DICTIONARY](../../sql-reference/statements/system.md#query_language-system-reload-dictionary) query, timeout, dictionary config has changed).
+    -   `FAILED_AND_RELOADING` — Could not load the dictionary as a result of an error and is loading now.
+-   `origin` ([String](../../sql-reference/data-types/string.md)) — Path to the configuration file that describes the dictionary.
+-   `type` ([String](../../sql-reference/data-types/string.md)) — Type of a dictionary allocation. [Storing Dictionaries in Memory](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md).
+-   `key.names` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Array of [key names](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-key) provided by the dictionary.
+-   `key.types` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Corresponding array of [key types](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-key) provided by the dictionary.
+-   `attribute.names` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Array of [attribute names](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-attributes) provided by the dictionary.
+-   `attribute.types` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Corresponding array of [attribute types](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-attributes) provided by the dictionary.
+-   `bytes_allocated` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Amount of RAM allocated for the dictionary.
+-   `query_count` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Number of queries since the dictionary was loaded or since the last successful reboot.
+-   `hit_rate` ([Float64](../../sql-reference/data-types/float.md)) — For cache dictionaries, the percentage of uses for which the value was in the cache.
+-   `found_rate` ([Float64](../../sql-reference/data-types/float.md)) — The percentage of uses for which the value was found.
+-   `element_count` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Number of items stored in the dictionary.
+-   `load_factor` ([Float64](../../sql-reference/data-types/float.md)) — Percentage filled in the dictionary (for a hashed dictionary, the percentage filled in the hash table).
+-   `source` ([String](../../sql-reference/data-types/string.md)) — Text describing the [data source](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md) for the dictionary.
+-   `lifetime_min` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Minimum [lifetime](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md) of the dictionary in memory, after which ClickHouse tries to reload the dictionary (if `invalidate_query` is set, then only if it has changed). Set in seconds.
+-   `lifetime_max` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Maximum [lifetime](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md) of the dictionary in memory, after which ClickHouse tries to reload the dictionary (if `invalidate_query` is set, then only if it has changed). Set in seconds.
+-   `loading_start_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Start time for loading the dictionary.
+-   `last_successful_update_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — End time for loading or updating the dictionary. Helps to monitor some troubles with external sources and investigate causes.
+-   `loading_duration` ([Float32](../../sql-reference/data-types/float.md)) — Duration of a dictionary loading.
+-   `last_exception` ([String](../../sql-reference/data-types/string.md)) — Text of the error that occurs when creating or reloading the dictionary if the dictionary couldn’t be created.
+-   `comment` ([String](../../sql-reference/data-types/string.md)) — Text of the comment to dictionary.
+
+**Example**
+
+Configure the dictionary:
+
+``` sql
+CREATE DICTIONARY dictionary_with_comment
+(
+    id UInt64,
+    value String
+)
+PRIMARY KEY id
+SOURCE(CLICKHOUSE(HOST 'localhost' PORT tcpPort() TABLE 'source_table'))
+LAYOUT(FLAT())
+LIFETIME(MIN 0 MAX 1000)
+COMMENT 'The temporary dictionary';
+```
+
+Make sure that the dictionary is loaded.
+
+``` sql
+SELECT * FROM system.dictionaries LIMIT 1 FORMAT Vertical;
+```
+
+``` text
+Row 1:
+──────
+database:                    default
+name:                        dictionary_with_comment
+uuid:                        4654d460-0d03-433a-8654-d4600d03d33a
+status:                      NOT_LOADED
+origin:                      4654d460-0d03-433a-8654-d4600d03d33a
+type:
+key.names:                   ['id']
+key.types:                   ['UInt64']
+attribute.names:             ['value']
+attribute.types:             ['String']
+bytes_allocated:             0
+query_count:                 0
+hit_rate:                    0
+found_rate:                  0
+element_count:               0
+load_factor:                 0
+source:
+lifetime_min:                0
+lifetime_max:                0
+loading_start_time:          1970-01-01 00:00:00
+last_successful_update_time: 1970-01-01 00:00:00
+loading_duration:            0
+last_exception:
+comment:                     The temporary dictionary
+```
diff --git a/docs/en/reference/operations/system-tables/disks.md b/docs/en/reference/operations/system-tables/disks.md
new file mode 100644
index 00000000000..869c0f3cee5
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/disks.md
@@ -0,0 +1,27 @@
+# disks {#system_tables-disks}
+
+Contains information about disks defined in the [server configuration](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes_configure).
+
+Columns:
+
+-   `name` ([String](../../sql-reference/data-types/string.md)) — Name of a disk in the server configuration.
+-   `path` ([String](../../sql-reference/data-types/string.md)) — Path to the mount point in the file system.
+-   `free_space` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Free space on disk in bytes.
+-   `total_space` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Disk volume in bytes.
+-   `keep_free_space` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Amount of disk space that should stay free on disk in bytes. Defined in the `keep_free_space_bytes` parameter of disk configuration.
+
+**Example**
+
+```sql
+:) SELECT * FROM system.disks;
+```
+
+```text
+┌─name────┬─path─────────────────┬───free_space─┬──total_space─┬─keep_free_space─┐
+│ default │ /var/lib/clickhouse/ │ 276392587264 │ 490652508160 │               0 │
+└─────────┴──────────────────────┴──────────────┴──────────────┴─────────────────┘
+
+1 rows in set. Elapsed: 0.001 sec.
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/disks) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/distributed_ddl_queue.md b/docs/en/reference/operations/system-tables/distributed_ddl_queue.md
new file mode 100644
index 00000000000..0597972197d
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/distributed_ddl_queue.md
@@ -0,0 +1,64 @@
+# distributed_ddl_queue {#system_tables-distributed_ddl_queue}
+
+Contains information about [distributed ddl queries (ON CLUSTER clause)](../../sql-reference/distributed-ddl.md) that were executed on a cluster.
+
+Columns:
+
+-   `entry` ([String](../../sql-reference/data-types/string.md)) — Query id.
+-   `host_name` ([String](../../sql-reference/data-types/string.md)) — Hostname.
+-   `host_address` ([String](../../sql-reference/data-types/string.md)) — IP address that the Hostname resolves to.
+-   `port` ([UInt16](../../sql-reference/data-types/int-uint.md)) — Host Port.
+-   `status` ([Enum8](../../sql-reference/data-types/enum.md)) — Status of the query.
+-   `cluster` ([String](../../sql-reference/data-types/string.md)) — Cluster name.
+-   `query` ([String](../../sql-reference/data-types/string.md)) — Query executed.
+-   `initiator` ([String](../../sql-reference/data-types/string.md)) — Node that executed the query.
+-   `query_start_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Query start time.
+-   `query_finish_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Query finish time.
+-   `query_duration_ms` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Duration of query execution (in milliseconds).
+-   `exception_code` ([Enum8](../../sql-reference/data-types/enum.md)) — Exception code from [ZooKeeper](../../operations/tips.md#zookeeper).
+
+**Example**
+
+``` sql
+SELECT *
+FROM system.distributed_ddl_queue
+WHERE cluster = 'test_cluster'
+LIMIT 2
+FORMAT Vertical
+
+Query id: f544e72a-6641-43f1-836b-24baa1c9632a
+
+Row 1:
+──────
+entry:             query-0000000000
+host_name:         clickhouse01
+host_address:      172.23.0.11
+port:              9000
+status:            Finished
+cluster:           test_cluster
+query:             CREATE DATABASE test_db UUID '4a82697e-c85e-4e5b-a01e-a36f2a758456' ON CLUSTER test_cluster
+initiator:         clickhouse01:9000
+query_start_time:  2020-12-30 13:07:51
+query_finish_time: 2020-12-30 13:07:51
+query_duration_ms: 6
+exception_code:    ZOK
+
+Row 2:
+──────
+entry:             query-0000000000
+host_name:         clickhouse02
+host_address:      172.23.0.12
+port:              9000
+status:            Finished
+cluster:           test_cluster
+query:             CREATE DATABASE test_db UUID '4a82697e-c85e-4e5b-a01e-a36f2a758456' ON CLUSTER test_cluster
+initiator:         clickhouse01:9000
+query_start_time:  2020-12-30 13:07:51
+query_finish_time: 2020-12-30 13:07:51
+query_duration_ms: 6
+exception_code:    ZOK
+
+2 rows in set. Elapsed: 0.025 sec.
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system_tables/distributed_ddl_queuedistributed_ddl_queue.md) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/distribution_queue.md b/docs/en/reference/operations/system-tables/distribution_queue.md
new file mode 100644
index 00000000000..231a06458c8
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/distribution_queue.md
@@ -0,0 +1,50 @@
+# distribution_queue {#system_tables-distribution_queue}
+
+Contains information about local files that are in the queue to be sent to the shards. These local files contain new parts that are created by inserting new data into the Distributed table in asynchronous mode.
+
+Columns:
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) — Name of the database.
+
+-   `table` ([String](../../sql-reference/data-types/string.md)) — Name of the table.
+
+-   `data_path` ([String](../../sql-reference/data-types/string.md)) — Path to the folder with local files.
+
+-   `is_blocked` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag indicates whether sending local files to the server is blocked.
+
+-   `error_count` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Number of errors.
+
+-   `data_files` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Number of local files in a folder.
+
+-   `data_compressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Size of compressed data in local files, in bytes.
+
+-   `broken_data_files` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Number of files that has been marked as broken (due to an error).
+
+-   `broken_data_compressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Size of compressed data in broken files, in bytes.
+
+-   `last_exception` ([String](../../sql-reference/data-types/string.md)) — Text message about the last error that occurred (if any).
+
+**Example**
+
+``` sql
+SELECT * FROM system.distribution_queue LIMIT 1 FORMAT Vertical;
+```
+
+``` text
+Row 1:
+──────
+database:              default
+table:                 dist
+data_path:             ./store/268/268bc070-3aad-4b1a-9cf2-4987580161af/default@127%2E0%2E0%2E2:9000/
+is_blocked:            1
+error_count:           0
+data_files:            1
+data_compressed_bytes: 499
+last_exception:
+```
+
+**See Also**
+
+-   [Distributed table engine](../../engines/table-engines/special/distributed.md)
+
+[Original article](https://clickhouse.com/docs/en/operations/system_tables/distribution_queue) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/enabled-roles.md b/docs/en/reference/operations/system-tables/enabled-roles.md
new file mode 100644
index 00000000000..832fc6aba42
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/enabled-roles.md
@@ -0,0 +1,12 @@
+# enabled_roles {#system_tables-enabled_roles}
+
+Contains all active roles at the moment, including current role of the current user and granted roles for current role.
+
+Columns:
+
+- `role_name` ([String](../../sql-reference/data-types/string.md))) — Role name.
+- `with_admin_option` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Flag that shows whether `enabled_role` is a role with `ADMIN OPTION` privilege.
+- `is_current` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Flag that shows whether `enabled_role` is a current role of a current user.
+- `is_default` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Flag that shows whether `enabled_role` is a default role.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/enabled-roles) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/errors.md b/docs/en/reference/operations/system-tables/errors.md
new file mode 100644
index 00000000000..8e60cf93bfa
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/errors.md
@@ -0,0 +1,36 @@
+# errors {#system_tables-errors}
+
+Contains error codes with the number of times they have been triggered.
+
+Columns:
+
+-   `name` ([String](../../sql-reference/data-types/string.md)) — name of the error (`errorCodeToName`).
+-   `code` ([Int32](../../sql-reference/data-types/int-uint.md)) — code number of the error.
+-   `value` ([UInt64](../../sql-reference/data-types/int-uint.md)) — the number of times this error has been happened.
+-   `last_error_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — time when the last error happened.
+-   `last_error_message` ([String](../../sql-reference/data-types/string.md)) — message for the last error.
+-   `last_error_trace` ([Array(UInt64)](../../sql-reference/data-types/array.md)) — A [stack trace](https://en.wikipedia.org/wiki/Stack_trace) which represents a list of physical addresses where the called methods are stored.
+-   `remote` ([UInt8](../../sql-reference/data-types/int-uint.md)) — remote exception (i.e. received during one of the distributed query).
+
+**Example**
+
+``` sql
+SELECT name, code, value
+FROM system.errors
+WHERE value > 0
+ORDER BY code ASC
+LIMIT 1
+
+┌─name─────────────┬─code─┬─value─┐
+│ CANNOT_OPEN_FILE │   76 │     1 │
+└──────────────────┴──────┴───────┘
+```
+
+``` sql
+WITH arrayMap(x -> demangle(addressToSymbol(x)), last_error_trace) AS all
+SELECT name, arrayStringConcat(all, '\n') AS res
+FROM system.errors
+LIMIT 1
+SETTINGS allow_introspection_functions=1\G
+```
+
diff --git a/docs/en/reference/operations/system-tables/events.md b/docs/en/reference/operations/system-tables/events.md
new file mode 100644
index 00000000000..445573ec978
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/events.md
@@ -0,0 +1,34 @@
+# events {#system_tables-events}
+
+Contains information about the number of events that have occurred in the system. For example, in the table, you can find how many `SELECT` queries were processed since the ClickHouse server started.
+
+Columns:
+
+-   `event` ([String](../../sql-reference/data-types/string.md)) — Event name.
+-   `value` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Number of events occurred.
+-   `description` ([String](../../sql-reference/data-types/string.md)) — Event description.
+
+**Example**
+
+``` sql
+SELECT * FROM system.events LIMIT 5
+```
+
+``` text
+┌─event─────────────────────────────────┬─value─┬─description────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Query                                 │    12 │ Number of queries to be interpreted and potentially executed. Does not include queries that failed to parse or were rejected due to AST size limits, quota limits or limits on the number of simultaneously running queries. May include internal queries initiated by ClickHouse itself. Does not count subqueries.                  │
+│ SelectQuery                           │     8 │ Same as Query, but only for SELECT queries.                                                                                                                                                                                                                │
+│ FileOpen                              │    73 │ Number of files opened.                                                                                                                                                                                                                                    │
+│ ReadBufferFromFileDescriptorRead      │   155 │ Number of reads (read/pread) from a file descriptor. Does not include sockets.                                                                                                                                                                             │
+│ ReadBufferFromFileDescriptorReadBytes │  9931 │ Number of bytes read from file descriptors. If the file is compressed, this will show the compressed data size.                                                                                                                                              │
+└───────────────────────────────────────┴───────┴────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [system.asynchronous_metrics](../../operations/system-tables/asynchronous_metrics.md#system_tables-asynchronous_metrics) — Contains periodically calculated metrics.
+-   [system.metrics](../../operations/system-tables/metrics.md#system_tables-metrics) — Contains instantly calculated metrics.
+-   [system.metric_log](../../operations/system-tables/metric_log.md#system_tables-metric_log) — Contains a history of metrics values from tables `system.metrics` и `system.events`.
+-   [Monitoring](../../operations/monitoring.md) — Base concepts of ClickHouse monitoring.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/events) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/functions.md b/docs/en/reference/operations/system-tables/functions.md
new file mode 100644
index 00000000000..097b6ccd22a
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/functions.md
@@ -0,0 +1,33 @@
+# functions {#system-functions}
+
+Contains information about normal and aggregate functions.
+
+Columns:
+
+-   `name`(`String`) – The name of the function.
+-   `is_aggregate`(`UInt8`) — Whether the function is aggregate.
+
+**Example**
+
+```sql
+ SELECT * FROM system.functions LIMIT 10;
+```
+
+```text
+┌─name──────────────────┬─is_aggregate─┬─case_insensitive─┬─alias_to─┬─create_query─┬─origin─┐
+│ logTrace              │            0 │                0 │          │              │ System │
+│ aes_decrypt_mysql     │            0 │                0 │          │              │ System │
+│ aes_encrypt_mysql     │            0 │                0 │          │              │ System │
+│ decrypt               │            0 │                0 │          │              │ System │
+│ encrypt               │            0 │                0 │          │              │ System │
+│ toBool                │            0 │                0 │          │              │ System │
+│ windowID              │            0 │                0 │          │              │ System │
+│ hopStart              │            0 │                0 │          │              │ System │
+│ hop                   │            0 │                0 │          │              │ System │
+│ snowflakeToDateTime64 │            0 │                0 │          │              │ System │
+└───────────────────────┴──────────────┴──────────────────┴──────────┴──────────────┴────────┘
+
+10 rows in set. Elapsed: 0.002 sec.
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/functions) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/grants.md b/docs/en/reference/operations/system-tables/grants.md
new file mode 100644
index 00000000000..c848972c2d8
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/grants.md
@@ -0,0 +1,24 @@
+# grants {#system_tables-grants}
+
+Privileges granted to ClickHouse user accounts.
+
+Columns:
+-    `user_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — User name.
+
+-    `role_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Role assigned to user account.
+
+-    `access_type` ([Enum8](../../sql-reference/data-types/enum.md)) — Access parameters for ClickHouse user account.
+
+-    `database` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Name of a database.
+
+-    `table` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Name of a table.
+
+-    `column` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Name of a column to which access is granted.
+
+-    `is_partial_revoke` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Logical value. It shows whether some privileges have been revoked. Possible values:
+- `0` — The row describes a partial revoke.
+- `1` — The row describes a grant.
+
+-    `grant_option` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Permission is granted `WITH GRANT OPTION`, see [GRANT](../../sql-reference/statements/grant.md#grant-privigele-syntax).
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/grants) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/graphite_retentions.md b/docs/en/reference/operations/system-tables/graphite_retentions.md
new file mode 100644
index 00000000000..10e265815f4
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/graphite_retentions.md
@@ -0,0 +1,17 @@
+# graphite_retentions {#system-graphite-retentions}
+
+Contains information about parameters [graphite_rollup](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-graphite) which are used in tables with [\*GraphiteMergeTree](../../engines/table-engines/mergetree-family/graphitemergetree.md) engines.
+
+Columns:
+
+-   `config_name` (String) - `graphite_rollup` parameter name.
+-   `regexp` (String) - A pattern for the metric name.
+-   `function` (String) - The name of the aggregating function.
+-   `age` (UInt64) - The minimum age of the data in seconds.
+-   `precision` (UInt64) - How precisely to define the age of the data in seconds.
+-   `priority` (UInt16) - Pattern priority.
+-   `is_default` (UInt8) - Whether the pattern is the default.
+-   `Tables.database` (Array(String)) - Array of names of database tables that use the `config_name` parameter.
+-   `Tables.table` (Array(String)) - Array of table names that use the `config_name` parameter.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/graphite_retentions) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/index.md b/docs/en/reference/operations/system-tables/index.md
new file mode 100644
index 00000000000..7b977ab4d51
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/index.md
@@ -0,0 +1,74 @@
+---
+sidebar_position: 52
+sidebar_label: System Tables
+---
+
+# System Tables {#system-tables}
+
+## Introduction {#system-tables-introduction}
+
+System tables provide information about:
+
+-   Server states, processes, and environment.
+-   Server’s internal processes.
+
+System tables:
+
+-   Located in the `system` database.
+-   Available only for reading data.
+-   Can’t be dropped or altered, but can be detached.
+
+Most of system tables store their data in RAM. A ClickHouse server creates such system tables at the start.
+
+Unlike other system tables, the system log tables [metric_log](../../operations/system-tables/metric_log.md), [query_log](../../operations/system-tables/query_log.md), [query_thread_log](../../operations/system-tables/query_thread_log.md), [trace_log](../../operations/system-tables/trace_log.md), [part_log](../../operations/system-tables/part_log.md), [crash_log](../../operations/system-tables/crash-log.md) and [text_log](../../operations/system-tables/text_log.md) are served by [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) table engine and store their data in a filesystem by default. If you remove a table from a filesystem, the ClickHouse server creates the empty one again at the time of the next data writing. If system table schema changed in a new release, then ClickHouse renames the current table and creates a new one.
+
+System log tables can be customized by creating a config file with the same name as the table under `/etc/clickhouse-server/config.d/`, or setting corresponding elements in `/etc/clickhouse-server/config.xml`. Elements can be customized are:
+
+-   `database`: database the system log table belongs to. This option is deprecated now. All system log tables are under database `system`.
+-   `table`: table to insert data.
+-   `partition_by`: specify [PARTITION BY](../../engines/table-engines/mergetree-family/custom-partitioning-key.md) expression.
+-   `ttl`: specify table [TTL](../../sql-reference/statements/alter/ttl.md) expression.
+-   `flush_interval_milliseconds`: interval of flushing data to disk.
+-   `engine`: provide full engine expression (starting with `ENGINE =` ) with parameters. This option is contradict with `partition_by` and `ttl`. If set together, the server would raise an exception and exit.
+
+An example:
+
+```xml
+<clickhouse>
+    <query_log>
+        <database>system</database>
+        <table>query_log</table>
+        <partition_by>toYYYYMM(event_date)</partition_by>
+        <ttl>event_date + INTERVAL 30 DAY DELETE</ttl>
+        <!--
+        <engine>ENGINE = MergeTree PARTITION BY toYYYYMM(event_date) ORDER BY (event_date, event_time) SETTINGS index_granularity = 1024</engine>
+        -->
+        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+    </query_log>
+</clickhouse>
+```
+
+By default, table growth is unlimited. To control a size of a table, you can use [TTL](../../sql-reference/statements/alter/ttl.md#manipulations-with-table-ttl) settings for removing outdated log records. Also you can use the partitioning feature of `MergeTree`-engine tables.
+
+## Sources of System Metrics {#system-tables-sources-of-system-metrics}
+
+For collecting system metrics ClickHouse server uses:
+
+-   `CAP_NET_ADMIN` capability.
+-   [procfs](https://en.wikipedia.org/wiki/Procfs) (only in Linux).
+
+**procfs**
+
+If ClickHouse server does not have `CAP_NET_ADMIN` capability, it tries to fall back to `ProcfsMetricsProvider`. `ProcfsMetricsProvider` allows collecting per-query system metrics (for CPU and I/O).
+
+If procfs is supported and enabled on the system, ClickHouse server collects these metrics:
+
+-   `OSCPUVirtualTimeMicroseconds`
+-   `OSCPUWaitMicroseconds`
+-   `OSIOWaitMicroseconds`
+-   `OSReadChars`
+-   `OSWriteChars`
+-   `OSReadBytes`
+-   `OSWriteBytes`
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/information_schema.md b/docs/en/reference/operations/system-tables/information_schema.md
new file mode 100644
index 00000000000..df5b012f2b6
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/information_schema.md
@@ -0,0 +1,210 @@
+# INFORMATION_SCHEMA {#information-schema}
+
+`INFORMATION_SCHEMA` (`information_schema`) is a system database that contains views. Using these views, you can get information about the metadata of database objects. These views read data from the columns of the [system.columns](../../operations/system-tables/columns.md), [system.databases](../../operations/system-tables/databases.md) and [system.tables](../../operations/system-tables/tables.md) system tables.
+
+The structure and composition of system tables may change in different versions of the product, but the support of the `information_schema` makes it possible to change the structure of system tables without changing the method of access to metadata. Metadata requests do not depend on the DBMS used.
+
+``` sql
+SHOW TABLES FROM INFORMATION_SCHEMA;
+```
+
+``` text
+┌─name─────┐
+│ COLUMNS  │
+│ SCHEMATA │
+│ TABLES   │
+│ VIEWS    │
+└──────────┘
+```
+
+`INFORMATION_SCHEMA` contains the following views:
+
+-   [COLUMNS](#columns)
+-   [SCHEMATA](#schemata)
+-   [TABLES](#tables)
+-   [VIEWS](#views)
+
+## COLUMNS {#columns}
+
+Contains columns read from the [system.columns](../../operations/system-tables/columns.md) system table and columns that are not supported in ClickHouse or do not make sense (always `NULL`), but must be by the standard.
+
+Columns:
+
+-   `table_catalog` ([String](../../sql-reference/data-types/string.md)) — The name of the database in which the table is located.
+-   `table_schema` ([String](../../sql-reference/data-types/string.md)) — The name of the database in which the table is located.
+-   `table_name` ([String](../../sql-reference/data-types/string.md)) — Table name.
+-   `column_name` ([String](../../sql-reference/data-types/string.md)) — Column name.
+-   `ordinal_position` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Ordinal position of a column in a table starting with 1.
+-   `column_default` ([String](../../sql-reference/data-types/string.md)) — Expression for the default value, or an empty string if it is not defined.
+-   `is_nullable` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag that indicates whether the column type is `Nullable`.
+-   `data_type` ([String](../../sql-reference/data-types/string.md)) — Column type.
+-   `character_maximum_length` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum length in bytes for binary data, character data, or text data and images. In ClickHouse makes sense only for `FixedString` data type. Otherwise, the `NULL` value is returned.
+-   `character_octet_length` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum length in bytes for binary data, character data, or text data and images. In ClickHouse makes sense only for `FixedString` data type. Otherwise, the `NULL` value is returned.
+-   `numeric_precision` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Accuracy of approximate numeric data, exact numeric data, integer data, or monetary data. In ClickHouse it is bitness for integer types and decimal precision for `Decimal` types. Otherwise, the `NULL` value is returned.
+-   `numeric_precision_radix` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The base of the number system is the accuracy of approximate numeric data, exact numeric data, integer data or monetary data. In ClickHouse it's 2 for integer types and 10 for `Decimal` types. Otherwise, the `NULL` value is returned.
+-   `numeric_scale` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The scale of approximate numeric data, exact numeric data, integer data, or monetary data. In ClickHouse makes sense only for `Decimal` types. Otherwise, the `NULL` value is returned.
+-   `datetime_precision` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Decimal precision of `DateTime64` data type. For other data types, the `NULL` value is returned.
+-   `character_set_catalog` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `character_set_schema` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `character_set_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `collation_catalog` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `collation_schema` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `collation_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `domain_catalog` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `domain_schema` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `domain_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE (table_schema=currentDatabase() OR table_schema='') AND table_name NOT LIKE '%inner%' LIMIT 1 FORMAT Vertical;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+table_catalog:            default
+table_schema:             default
+table_name:               describe_example
+column_name:              id
+ordinal_position:         1
+column_default:
+is_nullable:              0
+data_type:                UInt64
+character_maximum_length: ᴺᵁᴸᴸ
+character_octet_length:   ᴺᵁᴸᴸ
+numeric_precision:        64
+numeric_precision_radix:  2
+numeric_scale:            0
+datetime_precision:       ᴺᵁᴸᴸ
+character_set_catalog:    ᴺᵁᴸᴸ
+character_set_schema:     ᴺᵁᴸᴸ
+character_set_name:       ᴺᵁᴸᴸ
+collation_catalog:        ᴺᵁᴸᴸ
+collation_schema:         ᴺᵁᴸᴸ
+collation_name:           ᴺᵁᴸᴸ
+domain_catalog:           ᴺᵁᴸᴸ
+domain_schema:            ᴺᵁᴸᴸ
+domain_name:              ᴺᵁᴸᴸ
+```
+
+## SCHEMATA {#schemata}
+
+Contains columns read from the [system.databases](../../operations/system-tables/databases.md) system table and columns that are not supported in ClickHouse or do not make sense (always `NULL`), but must be by the standard.
+
+Columns:
+
+-   `catalog_name` ([String](../../sql-reference/data-types/string.md)) — The name of the database.
+-   `schema_name` ([String](../../sql-reference/data-types/string.md)) — The name of the database.
+-   `schema_owner` ([String](../../sql-reference/data-types/string.md)) — Schema owner name, always `'default'`.
+-   `default_character_set_catalog` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `default_character_set_schema` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `default_character_set_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+-   `sql_path` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — `NULL`, not supported.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT * FROM information_schema.schemata WHERE schema_name ILIKE 'information_schema' LIMIT 1 FORMAT Vertical;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+catalog_name:                  INFORMATION_SCHEMA
+schema_name:                   INFORMATION_SCHEMA
+schema_owner:                  default
+default_character_set_catalog: ᴺᵁᴸᴸ
+default_character_set_schema:  ᴺᵁᴸᴸ
+default_character_set_name:    ᴺᵁᴸᴸ
+sql_path:                      ᴺᵁᴸᴸ
+```
+
+## TABLES {#tables}
+
+Contains columns read from the [system.tables](../../operations/system-tables/tables.md) system table.
+
+Columns:
+
+-   `table_catalog` ([String](../../sql-reference/data-types/string.md)) — The name of the database in which the table is located.
+-   `table_schema` ([String](../../sql-reference/data-types/string.md)) — The name of the database in which the table is located.
+-   `table_name` ([String](../../sql-reference/data-types/string.md)) — Table name.
+-   `table_type` ([Enum8](../../sql-reference/data-types/enum.md)) — Table type. Possible values:
+    -   `BASE TABLE`
+    -   `VIEW`
+    -   `FOREIGN TABLE`
+    -   `LOCAL TEMPORARY`
+    -   `SYSTEM VIEW`
+
+**Example**
+
+Query:
+
+``` sql
+SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE (table_schema = currentDatabase() OR table_schema = '') AND table_name NOT LIKE '%inner%' LIMIT 1 FORMAT Vertical;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+table_catalog: default
+table_schema:  default
+table_name:    describe_example
+table_type:    BASE TABLE
+```
+
+## VIEWS {#views}
+
+Contains columns read from the [system.tables](../../operations/system-tables/tables.md) system table, when the table engine [View](../../engines/table-engines/special/view.md) is used.
+
+Columns:
+
+-   `table_catalog` ([String](../../sql-reference/data-types/string.md)) — The name of the database in which the table is located.
+-   `table_schema` ([String](../../sql-reference/data-types/string.md)) — The name of the database in which the table is located.
+-   `table_name` ([String](../../sql-reference/data-types/string.md)) — Table name.
+-   `view_definition` ([String](../../sql-reference/data-types/string.md)) — `SELECT` query for view.
+-   `check_option` ([String](../../sql-reference/data-types/string.md)) — `NONE`, no checking.
+-   `is_updatable` ([Enum8](../../sql-reference/data-types/enum.md)) — `NO`, the view is not updated.
+-   `is_insertable_into` ([Enum8](../../sql-reference/data-types/enum.md)) — Shows whether the created view is [materialized](../../sql-reference/statements/create/view/#materialized). Possible values:
+    -   `NO` — The created view is not materialized.
+    -   `YES` — The created view is materialized.
+-   `is_trigger_updatable` ([Enum8](../../sql-reference/data-types/enum.md)) — `NO`, the trigger is not updated.
+-   `is_trigger_deletable` ([Enum8](../../sql-reference/data-types/enum.md)) — `NO`, the trigger is not deleted.
+-   `is_trigger_insertable_into` ([Enum8](../../sql-reference/data-types/enum.md)) — `NO`, no data is inserted into the trigger.
+
+**Example**
+
+Query:
+
+``` sql
+CREATE VIEW v (n Nullable(Int32), f Float64) AS SELECT n, f FROM t;
+CREATE MATERIALIZED VIEW mv ENGINE = Null AS SELECT * FROM system.one;
+SELECT * FROM information_schema.views WHERE table_schema = currentDatabase() LIMIT 1 FORMAT Vertical;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+table_catalog:              default
+table_schema:               default
+table_name:                 mv
+view_definition:            SELECT * FROM system.one
+check_option:               NONE
+is_updatable:               NO
+is_insertable_into:         YES
+is_trigger_updatable:       NO
+is_trigger_deletable:       NO
+is_trigger_insertable_into: NO
+```
diff --git a/docs/en/reference/operations/system-tables/licenses.md b/docs/en/reference/operations/system-tables/licenses.md
new file mode 100644
index 00000000000..fad6e16fd8a
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/licenses.md
@@ -0,0 +1,39 @@
+# licenses 
+
+Сontains licenses of third-party libraries that are located in the [contrib](https://github.com/ClickHouse/ClickHouse/tree/master/contrib) directory of ClickHouse sources.
+
+Columns:
+
+- `library_name` ([String](../../sql-reference/data-types/string.md)) — Name of the library, which is license connected with.
+- `license_type` ([String](../../sql-reference/data-types/string.md)) — License type — e.g. Apache, MIT.
+- `license_path` ([String](../../sql-reference/data-types/string.md)) — Path to the file with the license text.
+- `license_text` ([String](../../sql-reference/data-types/string.md)) — License text.
+
+**Example**
+
+``` sql
+SELECT library_name, license_type, license_path FROM system.licenses LIMIT 15
+```
+
+``` text
+┌─library_name───────┬─license_type─┬─license_path────────────────────────┐
+│ FastMemcpy         │ MIT          │ /contrib/FastMemcpy/LICENSE         │
+│ arrow              │ Apache       │ /contrib/arrow/LICENSE.txt          │
+│ avro               │ Apache       │ /contrib/avro/LICENSE.txt           │
+│ aws-c-common       │ Apache       │ /contrib/aws-c-common/LICENSE       │
+│ aws-c-event-stream │ Apache       │ /contrib/aws-c-event-stream/LICENSE │
+│ aws-checksums      │ Apache       │ /contrib/aws-checksums/LICENSE      │
+│ aws                │ Apache       │ /contrib/aws/LICENSE.txt            │
+│ base64             │ BSD 2-clause │ /contrib/base64/LICENSE             │
+│ boost              │ Boost        │ /contrib/boost/LICENSE_1_0.txt      │
+│ brotli             │ MIT          │ /contrib/brotli/LICENSE             │
+│ capnproto          │ MIT          │ /contrib/capnproto/LICENSE          │
+│ cassandra          │ Apache       │ /contrib/cassandra/LICENSE.txt      │
+│ cctz               │ Apache       │ /contrib/cctz/LICENSE.txt           │
+│ cityhash102        │ MIT          │ /contrib/cityhash102/COPYING        │
+│ cppkafka           │ BSD 2-clause │ /contrib/cppkafka/LICENSE           │
+└────────────────────┴──────────────┴─────────────────────────────────────┘
+
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/licenses) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/merge_tree_settings.md b/docs/en/reference/operations/system-tables/merge_tree_settings.md
new file mode 100644
index 00000000000..0324d5c633d
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/merge_tree_settings.md
@@ -0,0 +1,54 @@
+# merge_tree_settings {#system-merge_tree_settings}
+
+Contains information about settings for `MergeTree` tables.
+
+Columns:
+
+-   `name` (String) — Setting name.
+-   `value` (String) — Setting value.
+-   `description` (String) — Setting description.
+-   `type` (String) — Setting type (implementation specific string value).
+-   `changed` (UInt8) — Whether the setting was explicitly defined in the config or explicitly changed.
+
+**Example**
+```sql
+:) SELECT * FROM system.merge_tree_settings LIMIT 4 FORMAT Vertical;
+```
+
+```text
+Row 1:
+──────
+name:        index_granularity
+value:       8192
+changed:     0
+description: How many rows correspond to one primary key value.
+type:        SettingUInt64
+
+Row 2:
+──────
+name:        min_bytes_for_wide_part
+value:       0
+changed:     0
+description: Minimal uncompressed size in bytes to create part in wide format instead of compact
+type:        SettingUInt64
+
+Row 3:
+──────
+name:        min_rows_for_wide_part
+value:       0
+changed:     0
+description: Minimal number of rows to create part in wide format instead of compact
+type:        SettingUInt64
+
+Row 4:
+──────
+name:        merge_max_block_size
+value:       8192
+changed:     0
+description: How many rows in blocks should be formed for merge operations.
+type:        SettingUInt64
+
+4 rows in set. Elapsed: 0.001 sec.
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/merge_tree_settings) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/merges.md b/docs/en/reference/operations/system-tables/merges.md
new file mode 100644
index 00000000000..f512e00fc89
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/merges.md
@@ -0,0 +1,25 @@
+# merges {#system-merges}
+
+Contains information about merges and part mutations currently in process for tables in the MergeTree family.
+
+Columns:
+
+-   `database` (String) — The name of the database the table is in.
+-   `table` (String) — Table name.
+-   `elapsed` (Float64) — The time elapsed (in seconds) since the merge started.
+-   `progress` (Float64) — The percentage of completed work from 0 to 1.
+-   `num_parts` (UInt64) — The number of pieces to be merged.
+-   `result_part_name` (String) — The name of the part that will be formed as the result of merging.
+-   `is_mutation` (UInt8) — 1 if this process is a part mutation.
+-   `total_size_bytes_compressed` (UInt64) — The total size of the compressed data in the merged chunks.
+-   `total_size_marks` (UInt64) — The total number of marks in the merged parts.
+-   `bytes_read_uncompressed` (UInt64) — Number of bytes read, uncompressed.
+-   `rows_read` (UInt64) — Number of rows read.
+-   `bytes_written_uncompressed` (UInt64) — Number of bytes written, uncompressed.
+-   `rows_written` (UInt64) — Number of rows written.
+-   `memory_usage` (UInt64) — Memory consumption of the merge process.
+-   `thread_id` (UInt64) — Thread ID of the merge process.
+-   `merge_type` — The type of current merge. Empty if it's an mutation.
+-   `merge_algorithm` — The algorithm used in current merge. Empty if it's an mutation.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/merges) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/metric_log.md b/docs/en/reference/operations/system-tables/metric_log.md
new file mode 100644
index 00000000000..55b0d800ead
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/metric_log.md
@@ -0,0 +1,51 @@
+# metric_log {#system_tables-metric_log}
+
+Contains history of metrics values from tables `system.metrics` and `system.events`, periodically flushed to disk.
+
+Columns:
+-   `event_date` ([Date](../../sql-reference/data-types/date.md)) — Event date.
+-   `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Event time.
+-   `event_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Event time with microseconds resolution.
+
+**Example**
+
+``` sql
+SELECT * FROM system.metric_log LIMIT 1 FORMAT Vertical;
+```
+
+``` text
+Row 1:
+──────
+event_date:                                                      2020-09-05
+event_time:                                                      2020-09-05 16:22:33
+event_time_microseconds:                                         2020-09-05 16:22:33.196807
+milliseconds:                                                    196
+ProfileEvent_Query:                                              0
+ProfileEvent_SelectQuery:                                        0
+ProfileEvent_InsertQuery:                                        0
+ProfileEvent_FailedQuery:                                        0
+ProfileEvent_FailedSelectQuery:                                  0
+...
+...
+CurrentMetric_Revision:                                          54439
+CurrentMetric_VersionInteger:                                    20009001
+CurrentMetric_RWLockWaitingReaders:                              0
+CurrentMetric_RWLockWaitingWriters:                              0
+CurrentMetric_RWLockActiveReaders:                               0
+CurrentMetric_RWLockActiveWriters:                               0
+CurrentMetric_GlobalThread:                                      74
+CurrentMetric_GlobalThreadActive:                                26
+CurrentMetric_LocalThread:                                       0
+CurrentMetric_LocalThreadActive:                                 0
+CurrentMetric_DistributedFilesToInsert:                          0
+```
+
+**See also**
+
+-   [metric_log setting](../../operations/server-configuration-parameters/settings.md#metric_log) — Enabling and disabling the setting.
+-   [system.asynchronous_metrics](../../operations/system-tables/asynchronous_metrics.md) — Contains periodically calculated metrics.
+-   [system.events](../../operations/system-tables/events.md#system_tables-events) — Contains a number of events that occurred.
+-   [system.metrics](../../operations/system-tables/metrics.md) — Contains instantly calculated metrics.
+-   [Monitoring](../../operations/monitoring.md) — Base concepts of ClickHouse monitoring.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/metric_log) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/metrics.md b/docs/en/reference/operations/system-tables/metrics.md
new file mode 100644
index 00000000000..d4e06e1aca6
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/metrics.md
@@ -0,0 +1,41 @@
+# metrics {#system_tables-metrics}
+
+Contains metrics which can be calculated instantly, or have a current value. For example, the number of simultaneously processed queries or the current replica delay. This table is always up to date.
+
+Columns:
+
+-   `metric` ([String](../../sql-reference/data-types/string.md)) — Metric name.
+-   `value` ([Int64](../../sql-reference/data-types/int-uint.md)) — Metric value.
+-   `description` ([String](../../sql-reference/data-types/string.md)) — Metric description.
+
+The list of supported metrics you can find in the [src/Common/CurrentMetrics.cpp](https://github.com/ClickHouse/ClickHouse/blob/master/src/Common/CurrentMetrics.cpp) source file of ClickHouse.
+
+**Example**
+
+``` sql
+SELECT * FROM system.metrics LIMIT 10
+```
+
+``` text
+┌─metric─────────────────────┬─value─┬─description──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Query                      │     1 │ Number of executing queries                                                                                                                                                                      │
+│ Merge                      │     0 │ Number of executing background merges                                                                                                                                                            │
+│ PartMutation               │     0 │ Number of mutations (ALTER DELETE/UPDATE)                                                                                                                                                        │
+│ ReplicatedFetch            │     0 │ Number of data parts being fetched from replicas                                                                                                                                                │
+│ ReplicatedSend             │     0 │ Number of data parts being sent to replicas                                                                                                                                                      │
+│ ReplicatedChecks           │     0 │ Number of data parts checking for consistency                                                                                                                                                    │
+│ BackgroundPoolTask         │     0 │ Number of active tasks in BackgroundProcessingPool (merges, mutations, fetches, or replication queue bookkeeping)                                                                                │
+│ BackgroundSchedulePoolTask │     0 │ Number of active tasks in BackgroundSchedulePool. This pool is used for periodic ReplicatedMergeTree tasks, like cleaning old data parts, altering data parts, replica re-initialization, etc.   │
+│ DiskSpaceReservedForMerge  │     0 │ Disk space reserved for currently running background merges. It is slightly more than the total size of currently merging parts.                                                                     │
+│ DistributedSend            │     0 │ Number of connections to remote servers sending data that was INSERTed into Distributed tables. Both synchronous and asynchronous mode.                                                          │
+└────────────────────────────┴───────┴──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [system.asynchronous_metrics](../../operations/system-tables/asynchronous_metrics.md#system_tables-asynchronous_metrics) — Contains periodically calculated metrics.
+-   [system.events](../../operations/system-tables/events.md#system_tables-events) — Contains a number of events that occurred.
+-   [system.metric_log](../../operations/system-tables/metric_log.md#system_tables-metric_log) — Contains a history of metrics values from tables `system.metrics` and `system.events`.
+-   [Monitoring](../../operations/monitoring.md) — Base concepts of ClickHouse monitoring.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/metrics) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/mutations.md b/docs/en/reference/operations/system-tables/mutations.md
new file mode 100644
index 00000000000..507146d93de
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/mutations.md
@@ -0,0 +1,49 @@
+# mutations {#system_tables-mutations}
+
+The table contains information about [mutations](../../sql-reference/statements/alter/index.md#mutations) of [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables and their progress. Each mutation command is represented by a single row.
+
+Columns:
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) — The name of the database to which the mutation was applied.
+
+-   `table` ([String](../../sql-reference/data-types/string.md)) — The name of the table to which the mutation was applied.
+
+-   `mutation_id` ([String](../../sql-reference/data-types/string.md)) — The ID of the mutation. For replicated tables these IDs correspond to znode names in the `<table_path_in_zookeeper>/mutations/` directory in ZooKeeper. For non-replicated tables the IDs correspond to file names in the data directory of the table.
+
+-   `command` ([String](../../sql-reference/data-types/string.md)) — The mutation command string (the part of the query after `ALTER TABLE [db.]table`).
+
+-   `create_time` ([Datetime](../../sql-reference/data-types/datetime.md)) —  Date and time when the mutation command was submitted for execution.
+
+-   `block_numbers.partition_id` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — For mutations of replicated tables, the array contains the partitions' IDs (one record for each partition). For mutations of non-replicated tables the array is empty.
+
+-   `block_numbers.number` ([Array](../../sql-reference/data-types/array.md)([Int64](../../sql-reference/data-types/int-uint.md))) — For mutations of replicated tables, the array contains one record for each partition, with the block number that was acquired by the mutation. Only parts that contain blocks with numbers less than this number will be mutated in the partition.
+
+    In non-replicated tables, block numbers in all partitions form a single sequence. This means that for mutations of non-replicated tables, the column will contain one record with a single block number acquired by the mutation.
+
+-   `parts_to_do_names` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — An array of names of data parts that need to be mutated for the mutation to complete.
+
+-   `parts_to_do` ([Int64](../../sql-reference/data-types/int-uint.md)) — The number of data parts that need to be mutated for the mutation to complete.
+
+-   `is_done` ([UInt8](../../sql-reference/data-types/int-uint.md)) — The flag whether the mutation is done or not. Possible values:
+    -   `1` if the mutation is completed,
+    -   `0` if the mutation is still in process.
+
+:::note
+Even if `parts_to_do = 0` it is possible that a mutation of a replicated table is not completed yet because of a long-running `INSERT` query, that will create a new data part needed to be mutated.
+:::
+
+If there were problems with mutating some data parts, the following columns contain additional information:
+
+-   `latest_failed_part` ([String](../../sql-reference/data-types/string.md)) — The name of the most recent part that could not be mutated.
+
+-   `latest_fail_time` ([Datetime](../../sql-reference/data-types/datetime.md)) — The date and time of the most recent part mutation failure.
+
+-   `latest_fail_reason` ([String](../../sql-reference/data-types/string.md)) — The exception message that caused the most recent part mutation failure.
+
+**See Also**
+
+-   [Mutations](../../sql-reference/statements/alter/index.md#mutations)
+-   [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) table engine
+-   [ReplicatedMergeTree](../../engines/table-engines/mergetree-family/replication.md) family
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/mutations) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/numbers.md b/docs/en/reference/operations/system-tables/numbers.md
new file mode 100644
index 00000000000..29828bfe796
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/numbers.md
@@ -0,0 +1,32 @@
+# numbers {#system-numbers}
+
+This table contains a single UInt64 column named `number` that contains almost all the natural numbers starting from zero.
+
+You can use this table for tests, or if you need to do a brute force search.
+
+Reads from this table are not parallelized.
+
+**Example**
+
+```sql
+:) SELECT * FROM system.numbers LIMIT 10;
+```
+
+```text
+┌─number─┐
+│      0 │
+│      1 │
+│      2 │
+│      3 │
+│      4 │
+│      5 │
+│      6 │
+│      7 │
+│      8 │
+│      9 │
+└────────┘
+
+10 rows in set. Elapsed: 0.001 sec.
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/numbers) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/numbers_mt.md b/docs/en/reference/operations/system-tables/numbers_mt.md
new file mode 100644
index 00000000000..02155db4711
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/numbers_mt.md
@@ -0,0 +1,30 @@
+# numbers_mt {#system-numbers-mt}
+
+The same as [system.numbers](../../operations/system-tables/numbers.md) but reads are parallelized. The numbers can be returned in any order.
+
+Used for tests.
+
+**Example**
+
+```sql
+:) SELECT * FROM system.numbers_mt LIMIT 10;
+```
+
+```text
+┌─number─┐
+│      0 │
+│      1 │
+│      2 │
+│      3 │
+│      4 │
+│      5 │
+│      6 │
+│      7 │
+│      8 │
+│      9 │
+└────────┘
+
+10 rows in set. Elapsed: 0.001 sec.
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/numbers_mt) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/one.md b/docs/en/reference/operations/system-tables/one.md
new file mode 100644
index 00000000000..9b84c0bfcd6
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/one.md
@@ -0,0 +1,23 @@
+# one {#system-one}
+
+This table contains a single row with a single `dummy` UInt8 column containing the value 0.
+
+This table is used if a `SELECT` query does not specify the `FROM` clause.
+
+This is similar to the `DUAL` table found in other DBMSs.
+
+**Example**
+
+```sql
+:) SELECT * FROM system.one LIMIT 10;
+```
+
+```text
+┌─dummy─┐
+│     0 │
+└───────┘
+
+1 rows in set. Elapsed: 0.001 sec.
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/one) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/opentelemetry_span_log.md b/docs/en/reference/operations/system-tables/opentelemetry_span_log.md
new file mode 100644
index 00000000000..89af72d6620
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/opentelemetry_span_log.md
@@ -0,0 +1,53 @@
+# opentelemetry_span_log {#system_tables-opentelemetry_span_log}
+
+Contains information about [trace spans](https://opentracing.io/docs/overview/spans/) for executed queries.
+
+Columns:
+
+-   `trace_id` ([UUID](../../sql-reference/data-types/uuid.md)) — ID of the trace for executed query.
+
+-   `span_id` ([UInt64](../../sql-reference/data-types/int-uint.md)) — ID of the `trace span`.
+
+-   `parent_span_id` ([UInt64](../../sql-reference/data-types/int-uint.md)) — ID of the parent `trace span`.
+
+-   `operation_name` ([String](../../sql-reference/data-types/string.md)) — The name of the operation.
+
+-   `start_time_us` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The start time of the `trace span` (in microseconds).
+
+-   `finish_time_us` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The finish time of the `trace span` (in microseconds).
+
+-   `finish_date` ([Date](../../sql-reference/data-types/date.md)) — The finish date of the `trace span`.
+
+-   `attribute.names` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — [Attribute](https://opentelemetry.io/docs/go/instrumentation/#attributes) names depending on the `trace span`. They are filled in according to the recommendations in the [OpenTelemetry](https://opentelemetry.io/) standard.
+
+-   `attribute.values` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Attribute values depending on the `trace span`. They are filled in according to the recommendations in the `OpenTelemetry` standard.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT * FROM system.opentelemetry_span_log LIMIT 1 FORMAT Vertical;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+trace_id:         cdab0847-0d62-61d5-4d38-dd65b19a1914
+span_id:          701487461015578150
+parent_span_id:   2991972114672045096
+operation_name:   DB::Block DB::InterpreterSelectQuery::getSampleBlockImpl()
+start_time_us:    1612374594529090
+finish_time_us:   1612374594529108
+finish_date:      2021-02-03
+attribute.names:  []
+attribute.values: []
+```
+
+**See Also**
+
+-   [OpenTelemetry](../../operations/opentelemetry.md)
+
+[Original article](https://clickhouse.com/docs/en/operations/system_tables/opentelemetry_span_log) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/part_log.md b/docs/en/reference/operations/system-tables/part_log.md
new file mode 100644
index 00000000000..00eaca23862
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/part_log.md
@@ -0,0 +1,69 @@
+# part_log {#system_tables-part-log}
+
+The `system.part_log` table is created only if the [part_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-part-log) server setting is specified.
+
+This table contains information about events that occurred with [data parts](../../engines/table-engines/mergetree-family/custom-partitioning-key.md) in the [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) family tables, such as adding or merging data.
+
+The `system.part_log` table contains the following columns:
+
+-   `query_id` ([String](../../sql-reference/data-types/string.md)) — Identifier of the `INSERT` query that created this data part.
+-   `event_type` ([Enum8](../../sql-reference/data-types/enum.md)) — Type of the event that occurred with the data part. Can have one of the following values:
+    -   `NEW_PART` — Inserting of a new data part.
+    -   `MERGE_PARTS` — Merging of data parts.
+    -   `DOWNLOAD_PART` — Downloading a data part.
+    -   `REMOVE_PART` — Removing or detaching a data part using [DETACH PARTITION](../../sql-reference/statements/alter/partition.md#alter_detach-partition).
+    -   `MUTATE_PART` — Mutating of a data part.
+    -   `MOVE_PART` — Moving the data part from the one disk to another one.
+-   `event_date` ([Date](../../sql-reference/data-types/date.md)) — Event date.
+-   `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Event time.
+-   `event_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Event time with microseconds precision.
+-   `duration_ms` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Duration.
+-   `database` ([String](../../sql-reference/data-types/string.md)) — Name of the database the data part is in.
+-   `table` ([String](../../sql-reference/data-types/string.md)) — Name of the table the data part is in.
+-   `part_name` ([String](../../sql-reference/data-types/string.md)) — Name of the data part.
+-   `partition_id` ([String](../../sql-reference/data-types/string.md)) — ID of the partition that the data part was inserted to. The column takes the `all` value if the partitioning is by `tuple()`.
+-   `path_on_disk` ([String](../../sql-reference/data-types/string.md)) — Absolute path to the folder with data part files.
+-   `rows` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The number of rows in the data part.
+-   `size_in_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Size of the data part in bytes.
+-   `merged_from` ([Array(String)](../../sql-reference/data-types/array.md)) — An array of names of the parts which the current part was made up from (after the merge).
+-   `bytes_uncompressed` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Size of uncompressed bytes.
+-   `read_rows` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The number of rows was read during the merge.
+-   `read_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The number of bytes was read during the merge.
+-   `peak_memory_usage` ([Int64](../../sql-reference/data-types/int-uint.md)) — The maximum difference between the amount of allocated and freed memory in context of this thread.
+-   `error` ([UInt16](../../sql-reference/data-types/int-uint.md)) — The code number of the occurred error.
+-   `exception` ([String](../../sql-reference/data-types/string.md)) — Text message of the occurred error.
+
+The `system.part_log` table is created after the first inserting data to the `MergeTree` table.
+
+**Example**
+
+``` sql
+SELECT * FROM system.part_log LIMIT 1 FORMAT Vertical;
+```
+
+``` text
+Row 1:
+──────
+query_id:                      983ad9c7-28d5-4ae1-844e-603116b7de31
+event_type:                    NewPart
+event_date:                    2021-02-02
+event_time:                    2021-02-02 11:14:28
+event_time_microseconds:                    2021-02-02 11:14:28.861919
+duration_ms:                   35
+database:                      default
+table:                         log_mt_2
+part_name:                     all_1_1_0
+partition_id:                  all
+path_on_disk:                  db/data/default/log_mt_2/all_1_1_0/
+rows:                          115418
+size_in_bytes:                 1074311
+merged_from:                   []
+bytes_uncompressed:            0
+read_rows:                     0
+read_bytes:                    0
+peak_memory_usage:             0
+error:                         0
+exception:
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/part_log) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/parts.md b/docs/en/reference/operations/system-tables/parts.md
new file mode 100644
index 00000000000..845c63e5626
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/parts.md
@@ -0,0 +1,168 @@
+# parts {#system_tables-parts}
+
+Contains information about parts of [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables.
+
+Each row describes one data part.
+
+Columns:
+
+-   `partition` ([String](../../sql-reference/data-types/string.md)) – The partition name. To learn what a partition is, see the description of the [ALTER](../../sql-reference/statements/alter/index.md#query_language_queries_alter) query.
+
+    Formats:
+
+    -   `YYYYMM` for automatic partitioning by month.
+    -   `any_string` when partitioning manually.
+
+-   `name` ([String](../../sql-reference/data-types/string.md)) – Name of the data part.
+
+-   `part_type` ([String](../../sql-reference/data-types/string.md)) — The data part storing format.
+
+    Possible Values:
+
+    -   `Wide` — Each column is stored in a separate file in a filesystem.
+    -   `Compact` — All columns are stored in one file in a filesystem.
+
+    Data storing format is controlled by the `min_bytes_for_wide_part` and `min_rows_for_wide_part` settings of the [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) table.
+
+   -   `active` ([UInt8](../../sql-reference/data-types/int-uint.md)) – Flag that indicates whether the data part is active. If a data part is active, it’s used in a table. Otherwise, it’s deleted. Inactive data parts remain after merging.
+
+-   `marks` ([UInt64](../../sql-reference/data-types/int-uint.md)) – The number of marks. To get the approximate number of rows in a data part, multiply `marks` by the index granularity (usually 8192) (this hint does not work for adaptive granularity).
+
+-   `rows` ([UInt64](../../sql-reference/data-types/int-uint.md)) – The number of rows.
+
+-   `bytes_on_disk` ([UInt64](../../sql-reference/data-types/int-uint.md)) – Total size of all the data part files in bytes.
+
+-   `data_compressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) – Total size of compressed data in the data part. All the auxiliary files (for example, files with marks) are not included.
+
+-   `data_uncompressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) – Total size of uncompressed data in the data part. All the auxiliary files (for example, files with marks) are not included.
+
+-   `marks_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) – The size of the file with marks.
+
+-   `secondary_indices_compressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) – Total size of compressed data for secondary indices in the data part. All the auxiliary files (for example, files with marks) are not included.
+
+-   `secondary_indices_uncompressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) – Total size of uncompressed data for secondary indices in the data part. All the auxiliary files (for example, files with marks) are not included.
+
+-   `secondary_indices_marks_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) – The size of the file with marks for secondary indices.
+
+-   `modification_time` ([DateTime](../../sql-reference/data-types/datetime.md)) – The time the directory with the data part was modified. This usually corresponds to the time of data part creation.
+
+-   `remove_time` ([DateTime](../../sql-reference/data-types/datetime.md)) – The time when the data part became inactive.
+
+-   `refcount` ([UInt32](../../sql-reference/data-types/int-uint.md)) – The number of places where the data part is used. A value greater than 2 indicates that the data part is used in queries or merges.
+
+-   `min_date` ([Date](../../sql-reference/data-types/date.md)) – The minimum value of the date key in the data part.
+
+-   `max_date` ([Date](../../sql-reference/data-types/date.md)) – The maximum value of the date key in the data part.
+
+-   `min_time` ([DateTime](../../sql-reference/data-types/datetime.md)) – The minimum value of the date and time key in the data part.
+
+-   `max_time`([DateTime](../../sql-reference/data-types/datetime.md)) – The maximum value of the date and time key in the data part.
+
+-   `partition_id` ([String](../../sql-reference/data-types/string.md)) – ID of the partition.
+
+-   `min_block_number` ([UInt64](../../sql-reference/data-types/int-uint.md)) – The minimum number of data parts that make up the current part after merging.
+
+-   `max_block_number` ([UInt64](../../sql-reference/data-types/int-uint.md)) – The maximum number of data parts that make up the current part after merging.
+
+-   `level` ([UInt32](../../sql-reference/data-types/int-uint.md)) – Depth of the merge tree. Zero means that the current part was created by insert rather than by merging other parts.
+
+-   `data_version` ([UInt64](../../sql-reference/data-types/int-uint.md)) – Number that is used to determine which mutations should be applied to the data part (mutations with a version higher than `data_version`).
+
+-   `primary_key_bytes_in_memory` ([UInt64](../../sql-reference/data-types/int-uint.md)) – The amount of memory (in bytes) used by primary key values.
+
+-   `primary_key_bytes_in_memory_allocated` ([UInt64](../../sql-reference/data-types/int-uint.md)) – The amount of memory (in bytes) reserved for primary key values.
+
+-   `is_frozen` ([UInt8](../../sql-reference/data-types/int-uint.md)) – Flag that shows that a partition data backup exists. 1, the backup exists. 0, the backup does not exist. For more details, see [FREEZE PARTITION](../../sql-reference/statements/alter/partition.md#alter_freeze-partition)
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) – Name of the database.
+
+-   `table` ([String](../../sql-reference/data-types/string.md)) – Name of the table.
+
+-   `engine` ([String](../../sql-reference/data-types/string.md)) – Name of the table engine without parameters.
+
+-   `path` ([String](../../sql-reference/data-types/string.md)) – Absolute path to the folder with data part files.
+
+-   `disk_name` ([String](../../sql-reference/data-types/string.md)) – Name of a disk that stores the data part.
+
+-   `hash_of_all_files` ([String](../../sql-reference/data-types/string.md)) – [sipHash128](../../sql-reference/functions/hash-functions.md#hash_functions-siphash128) of compressed files.
+
+-   `hash_of_uncompressed_files` ([String](../../sql-reference/data-types/string.md)) – [sipHash128](../../sql-reference/functions/hash-functions.md#hash_functions-siphash128) of uncompressed files (files with marks, index file etc.).
+
+-   `uncompressed_hash_of_compressed_files` ([String](../../sql-reference/data-types/string.md)) – [sipHash128](../../sql-reference/functions/hash-functions.md#hash_functions-siphash128) of data in the compressed files as if they were uncompressed.
+
+-   `delete_ttl_info_min` ([DateTime](../../sql-reference/data-types/datetime.md)) — The minimum value of the date and time key for [TTL DELETE rule](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl).
+
+-   `delete_ttl_info_max` ([DateTime](../../sql-reference/data-types/datetime.md)) — The maximum value of the date and time key for [TTL DELETE rule](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl).
+
+-   `move_ttl_info.expression` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Array of expressions. Each expression defines a [TTL MOVE rule](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl).
+
+:::warning
+The `move_ttl_info.expression` array is kept mostly for backward compatibility, now the simpliest way to check `TTL MOVE` rule is to use the `move_ttl_info.min` and `move_ttl_info.max` fields.
+:::
+
+-   `move_ttl_info.min` ([Array](../../sql-reference/data-types/array.md)([DateTime](../../sql-reference/data-types/datetime.md))) — Array of date and time values. Each element describes the minimum key value for a [TTL MOVE rule](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl).
+
+-   `move_ttl_info.max` ([Array](../../sql-reference/data-types/array.md)([DateTime](../../sql-reference/data-types/datetime.md))) — Array of date and time values. Each element describes the maximum key value for a [TTL MOVE rule](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl).
+
+-   `bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) – Alias for `bytes_on_disk`.
+
+-   `marks_size` ([UInt64](../../sql-reference/data-types/int-uint.md)) – Alias for `marks_bytes`.
+
+**Example**
+
+``` sql
+SELECT * FROM system.parts LIMIT 1 FORMAT Vertical;
+```
+
+``` text
+Row 1:
+──────
+partition:                             tuple()
+name:                                  all_1_4_1_6
+part_type:                             Wide
+active:                                1
+marks:                                 2
+rows:                                  6
+bytes_on_disk:                         310
+data_compressed_bytes:                 157
+data_uncompressed_bytes:               91
+secondary_indices_compressed_bytes:    58
+secondary_indices_uncompressed_bytes:  6
+secondary_indices_marks_bytes:         48
+marks_bytes:                           144
+modification_time:                     2020-06-18 13:01:49
+remove_time:                           1970-01-01 00:00:00
+refcount:                              1
+min_date:                              1970-01-01
+max_date:                              1970-01-01
+min_time:                              1970-01-01 00:00:00
+max_time:                              1970-01-01 00:00:00
+partition_id:                          all
+min_block_number:                      1
+max_block_number:                      4
+level:                                 1
+data_version:                          6
+primary_key_bytes_in_memory:           8
+primary_key_bytes_in_memory_allocated: 64
+is_frozen:                             0
+database:                              default
+table:                                 months
+engine:                                MergeTree
+disk_name:                             default
+path:                                  /var/lib/clickhouse/data/default/months/all_1_4_1_6/
+hash_of_all_files:                     2d0657a16d9430824d35e327fcbd87bf
+hash_of_uncompressed_files:            84950cc30ba867c77a408ae21332ba29
+uncompressed_hash_of_compressed_files: 1ad78f1c6843bbfb99a2c931abe7df7d
+delete_ttl_info_min:                   1970-01-01 00:00:00
+delete_ttl_info_max:                   1970-01-01 00:00:00
+move_ttl_info.expression:              []
+move_ttl_info.min:                     []
+move_ttl_info.max:                     []
+```
+
+**See Also**
+
+-   [MergeTree family](../../engines/table-engines/mergetree-family/mergetree.md)
+-   [TTL for Columns and Tables](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/parts) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/parts_columns.md b/docs/en/reference/operations/system-tables/parts_columns.md
new file mode 100644
index 00000000000..e87be3fcd43
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/parts_columns.md
@@ -0,0 +1,148 @@
+# parts_columns {#system_tables-parts_columns}
+
+Contains information about parts and columns of [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables.
+
+Each row describes one data part.
+
+Columns:
+
+-   `partition` ([String](../../sql-reference/data-types/string.md)) — The partition name. To learn what a partition is, see the description of the [ALTER](../../sql-reference/statements/alter/index.md#query_language_queries_alter) query.
+
+    Formats:
+
+    -   `YYYYMM` for automatic partitioning by month.
+    -   `any_string` when partitioning manually.
+
+-   `name` ([String](../../sql-reference/data-types/string.md)) — Name of the data part.
+
+-   `part_type` ([String](../../sql-reference/data-types/string.md)) — The data part storing format.
+
+    Possible values:
+
+    -   `Wide` — Each column is stored in a separate file in a filesystem.
+    -   `Compact` — All columns are stored in one file in a filesystem.
+
+    Data storing format is controlled by the `min_bytes_for_wide_part` and `min_rows_for_wide_part` settings of the [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) table.
+
+-   `active` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag that indicates whether the data part is active. If a data part is active, it’s used in a table. Otherwise, it’s deleted. Inactive data parts remain after merging.
+
+-   `marks` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The number of marks. To get the approximate number of rows in a data part, multiply `marks` by the index granularity (usually 8192) (this hint does not work for adaptive granularity).
+
+-   `rows` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The number of rows.
+
+-   `bytes_on_disk` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Total size of all the data part files in bytes.
+
+-   `data_compressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Total size of compressed data in the data part. All the auxiliary files (for example, files with marks) are not included.
+
+-   `data_uncompressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Total size of uncompressed data in the data part. All the auxiliary files (for example, files with marks) are not included.
+
+-   `marks_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The size of the file with marks.
+
+-   `modification_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — The time the directory with the data part was modified. This usually corresponds to the time of data part creation.
+
+-   `remove_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — The time when the data part became inactive.
+
+-   `refcount` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The number of places where the data part is used. A value greater than 2 indicates that the data part is used in queries or merges.
+
+-   `min_date` ([Date](../../sql-reference/data-types/date.md)) — The minimum value of the date key in the data part.
+
+-   `max_date` ([Date](../../sql-reference/data-types/date.md)) — The maximum value of the date key in the data part.
+
+-   `partition_id` ([String](../../sql-reference/data-types/string.md)) — ID of the partition.
+
+-   `min_block_number` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The minimum number of data parts that make up the current part after merging.
+
+-   `max_block_number` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The maximum number of data parts that make up the current part after merging.
+
+-   `level` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Depth of the merge tree. Zero means that the current part was created by insert rather than by merging other parts.
+
+-   `data_version` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Number that is used to determine which mutations should be applied to the data part (mutations with a version higher than `data_version`).
+
+-   `primary_key_bytes_in_memory` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The amount of memory (in bytes) used by primary key values.
+
+-   `primary_key_bytes_in_memory_allocated` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The amount of memory (in bytes) reserved for primary key values.
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) — Name of the database.
+
+-   `table` ([String](../../sql-reference/data-types/string.md)) — Name of the table.
+
+-   `engine` ([String](../../sql-reference/data-types/string.md)) — Name of the table engine without parameters.
+
+-   `disk_name` ([String](../../sql-reference/data-types/string.md)) — Name of a disk that stores the data part.
+
+-   `path` ([String](../../sql-reference/data-types/string.md)) — Absolute path to the folder with data part files.
+
+-   `column` ([String](../../sql-reference/data-types/string.md)) — Name of the column.
+
+-   `type` ([String](../../sql-reference/data-types/string.md)) — Column type.
+
+-   `column_position` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Ordinal position of a column in a table starting with 1.
+
+-   `default_kind` ([String](../../sql-reference/data-types/string.md)) — Expression type (`DEFAULT`, `MATERIALIZED`, `ALIAS`) for the default value, or an empty string if it is not defined.
+
+-   `default_expression` ([String](../../sql-reference/data-types/string.md)) — Expression for the default value, or an empty string if it is not defined.
+
+-   `column_bytes_on_disk` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Total size of the column in bytes.
+
+-   `column_data_compressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Total size of compressed data in the column, in bytes.
+
+-   `column_data_uncompressed_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Total size of the decompressed data in the column, in bytes.
+
+-   `column_marks_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The size of the column with marks, in bytes.
+
+-   `bytes` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Alias for `bytes_on_disk`.
+
+-   `marks_size` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Alias for `marks_bytes`.
+
+**Example**
+
+``` sql
+SELECT * FROM system.parts_columns LIMIT 1 FORMAT Vertical;
+```
+
+``` text
+Row 1:
+──────
+partition:                             tuple()
+name:                                  all_1_2_1
+part_type:                             Wide
+active:                                1
+marks:                                 2
+rows:                                  2
+bytes_on_disk:                         155
+data_compressed_bytes:                 56
+data_uncompressed_bytes:               4
+marks_bytes:                           96
+modification_time:                     2020-09-23 10:13:36
+remove_time:                           2106-02-07 06:28:15
+refcount:                              1
+min_date:                              1970-01-01
+max_date:                              1970-01-01
+partition_id:                          all
+min_block_number:                      1
+max_block_number:                      2
+level:                                 1
+data_version:                          1
+primary_key_bytes_in_memory:           2
+primary_key_bytes_in_memory_allocated: 64
+database:                              default
+table:                                 53r93yleapyears
+engine:                                MergeTree
+disk_name:                             default
+path:                                  /var/lib/clickhouse/data/default/53r93yleapyears/all_1_2_1/
+column:                                id
+type:                                  Int8
+column_position:                       1
+default_kind:
+default_expression:
+column_bytes_on_disk:                  76
+column_data_compressed_bytes:          28
+column_data_uncompressed_bytes:        2
+column_marks_bytes:                    48
+```
+
+**See Also**
+
+-   [MergeTree family](../../engines/table-engines/mergetree-family/mergetree.md)
+
+[Original article](https://clickhouse.com/docs/en/operations/system_tables/parts_columns) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/processes.md b/docs/en/reference/operations/system-tables/processes.md
new file mode 100644
index 00000000000..f261ee9b696
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/processes.md
@@ -0,0 +1,61 @@
+# processes {#system_tables-processes}
+
+This system table is used for implementing the `SHOW PROCESSLIST` query.
+
+Columns:
+
+-   `user` (String) – The user who made the query. Keep in mind that for distributed processing, queries are sent to remote servers under the `default` user. The field contains the username for a specific query, not for a query that this query initiated.
+-   `address` (String) – The IP address the request was made from. The same for distributed processing. To track where a distributed query was originally made from, look at `system.processes` on the query requestor server.
+-   `elapsed` (Float64) – The time in seconds since request execution started.
+-   `rows_read` (UInt64) – The number of rows read from the table. For distributed processing, on the requestor server, this is the total for all remote servers.
+-   `bytes_read` (UInt64) – The number of uncompressed bytes read from the table. For distributed processing, on the requestor server, this is the total for all remote servers.
+-   `total_rows_approx` (UInt64) – The approximation of the total number of rows that should be read. For distributed processing, on the requestor server, this is the total for all remote servers. It can be updated during request processing, when new sources to process become known.
+-   `memory_usage` (UInt64) – Amount of RAM the request uses. It might not include some types of dedicated memory. See the [max_memory_usage](../../operations/settings/query-complexity.md#settings_max_memory_usage) setting.
+-   `query` (String) – The query text. For `INSERT`, it does not include the data to insert.
+-   `query_id` (String) – Query ID, if defined.
+
+```sql
+:) SELECT * FROM system.processes LIMIT 10 FORMAT Vertical;
+```
+
+```text
+Row 1:
+──────
+is_initial_query:     1
+user:                 default
+query_id:             35a360fa-3743-441d-8e1f-228c938268da
+address:              ::ffff:172.23.0.1
+port:                 47588
+initial_user:         default
+initial_query_id:     35a360fa-3743-441d-8e1f-228c938268da
+initial_address:      ::ffff:172.23.0.1
+initial_port:         47588
+interface:            1
+os_user:              bharatnc
+client_hostname:      tower
+client_name:          ClickHouse
+client_revision:      54437
+client_version_major: 20
+client_version_minor: 7
+client_version_patch: 2
+http_method:          0
+http_user_agent:
+quota_key:
+elapsed:              0.000582537
+is_cancelled:         0
+read_rows:            0
+read_bytes:           0
+total_rows_approx:    0
+written_rows:         0
+written_bytes:        0
+memory_usage:         0
+peak_memory_usage:    0
+query:                SELECT * from system.processes LIMIT 10 FORMAT Vertical;
+thread_ids:           [67]
+ProfileEvents:        {'Query':1,'SelectQuery':1,'ReadCompressedBytes':36,'CompressedReadBufferBlocks':1,'CompressedReadBufferBytes':10,'IOBufferAllocs':1,'IOBufferAllocBytes':89,'ContextLock':15,'RWLockAcquiredReadLocks':1}
+Settings:             {'background_pool_size':'32','load_balancing':'random','allow_suspicious_low_cardinality_types':'1','distributed_aggregation_memory_efficient':'1','skip_unavailable_shards':'1','log_queries':'1','max_bytes_before_external_group_by':'20000000000','max_bytes_before_external_sort':'20000000000','allow_introspection_functions':'1'}
+
+1 rows in set. Elapsed: 0.002 sec.
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/processes) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/query_log.md b/docs/en/reference/operations/system-tables/query_log.md
new file mode 100644
index 00000000000..a8fda41f7c2
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/query_log.md
@@ -0,0 +1,189 @@
+# query_log {#system_tables-query_log}
+
+Contains information about executed queries, for example, start time, duration of processing, error messages.
+
+:::note
+This table does not contain the ingested data for `INSERT` queries.
+:::
+
+You can change settings of queries logging in the [query_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-query-log) section of the server configuration.
+
+You can disable queries logging by setting [log_queries = 0](../../operations/settings/settings.md#settings-log-queries). We do not recommend to turn off logging because information in this table is important for solving issues.
+
+The flushing period of data is set in `flush_interval_milliseconds` parameter of the [query_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-query-log) server settings section. To force flushing, use the [SYSTEM FLUSH LOGS](../../sql-reference/statements/system.md#query_language-system-flush_logs) query.
+
+ClickHouse does not delete data from the table automatically. See [Introduction](../../operations/system-tables/index.md#system-tables-introduction) for more details.
+
+The `system.query_log` table registers two kinds of queries:
+
+1.  Initial queries that were run directly by the client.
+2.  Child queries that were initiated by other queries (for distributed query execution). For these types of queries, information about the parent queries is shown in the `initial_*` columns.
+
+Each query creates one or two rows in the `query_log` table, depending on the status (see the `type` column) of the query:
+
+1.  If the query execution was successful, two rows with the `QueryStart` and `QueryFinish` types are created.
+2.  If an error occurred during query processing, two events with the `QueryStart` and `ExceptionWhileProcessing` types are created.
+3.  If an error occurred before launching the query, a single event with the `ExceptionBeforeStart` type is created.
+
+You can use the [log_queries_probability](../../operations/settings/settings.md#log-queries-probability) setting to reduce the number of queries, registered in the `query_log` table.
+
+You can use the [log_formatted_queries](../../operations/settings/settings.md#settings-log-formatted-queries) setting to log formatted queries to the `formatted_query` column.
+
+Columns:
+
+-   `type` ([Enum8](../../sql-reference/data-types/enum.md)) — Type of an event that occurred when executing the query. Values:
+    -   `'QueryStart' = 1` — Successful start of query execution.
+    -   `'QueryFinish' = 2` — Successful end of query execution.
+    -   `'ExceptionBeforeStart' = 3` — Exception before the start of query execution.
+    -   `'ExceptionWhileProcessing' = 4` — Exception during the query execution.
+-   `event_date` ([Date](../../sql-reference/data-types/date.md)) — Query starting date.
+-   `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Query starting time.
+-   `event_time_microseconds` ([DateTime](../../sql-reference/data-types/datetime.md)) — Query starting time with microseconds precision.
+-   `query_start_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Start time of query execution.
+-   `query_start_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Start time of query execution with microsecond precision.
+-   `query_duration_ms` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Duration of query execution in milliseconds.
+-   `read_rows` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Total number of rows read from all tables and table functions participated in query. It includes usual subqueries, subqueries for `IN` and `JOIN`. For distributed queries `read_rows` includes the total number of rows read at all replicas. Each replica sends it’s `read_rows` value, and the server-initiator of the query summarizes all received and local values. The cache volumes do not affect this value.
+-   `read_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Total number of bytes read from all tables and table functions participated in query. It includes usual subqueries, subqueries for `IN` and `JOIN`. For distributed queries `read_bytes` includes the total number of rows read at all replicas. Each replica sends it’s `read_bytes` value, and the server-initiator of the query summarizes all received and local values. The cache volumes do not affect this value.
+-   `written_rows` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — For `INSERT` queries, the number of written rows. For other queries, the column value is 0.
+-   `written_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — For `INSERT` queries, the number of written bytes. For other queries, the column value is 0.
+-   `result_rows` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Number of rows in a result of the `SELECT` query, or a number of rows in the `INSERT` query.
+-   `result_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — RAM volume in bytes used to store a query result.
+-   `memory_usage` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Memory consumption by the query.
+-   `current_database` ([String](../../sql-reference/data-types/string.md)) — Name of the current database.
+-   `query` ([String](../../sql-reference/data-types/string.md)) — Query string.
+-   `formatted_query` ([String](../../sql-reference/data-types/string.md)) — Formatted query string.
+-   `normalized_query_hash` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Identical hash value without the values of literals for similar queries.
+-   `query_kind` ([LowCardinality(String)](../../sql-reference/data-types/lowcardinality.md)) — Type of the query.
+-   `databases` ([Array](../../sql-reference/data-types/array.md)([LowCardinality(String)](../../sql-reference/data-types/lowcardinality.md))) — Names of the databases present in the query.
+-   `tables` ([Array](../../sql-reference/data-types/array.md)([LowCardinality(String)](../../sql-reference/data-types/lowcardinality.md))) — Names of the tables present in the query.
+-   `views` ([Array](../../sql-reference/data-types/array.md)([LowCardinality(String)](../../sql-reference/data-types/lowcardinality.md))) — Names of the (materialized or live) views present in the query.
+-   `columns` ([Array](../../sql-reference/data-types/array.md)([LowCardinality(String)](../../sql-reference/data-types/lowcardinality.md))) — Names of the columns present in the query.
+-   `projections` ([String](../../sql-reference/data-types/string.md)) — Names of the projections used during the query execution.
+-   `exception_code` ([Int32](../../sql-reference/data-types/int-uint.md)) — Code of an exception.
+-   `exception` ([String](../../sql-reference/data-types/string.md)) — Exception message.
+-   `stack_trace` ([String](../../sql-reference/data-types/string.md)) — [Stack trace](https://en.wikipedia.org/wiki/Stack_trace). An empty string, if the query was completed successfully.
+-   `is_initial_query` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Query type. Possible values:
+    -   1 — Query was initiated by the client.
+    -   0 — Query was initiated by another query as part of distributed query execution.
+-   `user` ([String](../../sql-reference/data-types/string.md)) — Name of the user who initiated the current query.
+-   `query_id` ([String](../../sql-reference/data-types/string.md)) — ID of the query.
+-   `address` ([IPv6](../../sql-reference/data-types/domains/ipv6.md)) — IP address that was used to make the query.
+-   `port` ([UInt16](../../sql-reference/data-types/int-uint.md)) — The client port that was used to make the query.
+-   `initial_user` ([String](../../sql-reference/data-types/string.md)) — Name of the user who ran the initial query (for distributed query execution).
+-   `initial_query_id` ([String](../../sql-reference/data-types/string.md)) — ID of the initial query (for distributed query execution).
+-   `initial_address` ([IPv6](../../sql-reference/data-types/domains/ipv6.md)) — IP address that the parent query was launched from.
+-   `initial_port` ([UInt16](../../sql-reference/data-types/int-uint.md)) — The client port that was used to make the parent query.
+-   `initial_query_start_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Initial query starting time (for distributed query execution).
+-   `initial_query_start_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Initial query starting time with microseconds precision (for distributed query execution).
+-   `interface` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Interface that the query was initiated from. Possible values:
+    -   1 — TCP.
+    -   2 — HTTP.
+-   `os_user` ([String](../../sql-reference/data-types/string.md)) — Operating system username who runs [clickhouse-client](../../interfaces/cli.md).
+-   `client_hostname` ([String](../../sql-reference/data-types/string.md)) — Hostname of the client machine where the [clickhouse-client](../../interfaces/cli.md) or another TCP client is run.
+-   `client_name` ([String](../../sql-reference/data-types/string.md)) — The [clickhouse-client](../../interfaces/cli.md) or another TCP client name.
+-   `client_revision` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Revision of the [clickhouse-client](../../interfaces/cli.md) or another TCP client.
+-   `client_version_major` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Major version of the [clickhouse-client](../../interfaces/cli.md) or another TCP client.
+-   `client_version_minor` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Minor version of the [clickhouse-client](../../interfaces/cli.md) or another TCP client.
+-   `client_version_patch` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Patch component of the [clickhouse-client](../../interfaces/cli.md) or another TCP client version.
+-   `http_method` (UInt8) — HTTP method that initiated the query. Possible values:
+    -   0 — The query was launched from the TCP interface.
+    -   1 — `GET` method was used.
+    -   2 — `POST` method was used.
+-   `http_user_agent` ([String](../../sql-reference/data-types/string.md)) — HTTP header `UserAgent` passed in the HTTP query.
+-   `http_referer` ([String](../../sql-reference/data-types/string.md)) — HTTP header `Referer` passed in the HTTP query (contains an absolute or partial address of the page making the query).
+-   `forwarded_for` ([String](../../sql-reference/data-types/string.md)) — HTTP header `X-Forwarded-For` passed in the HTTP query.
+-   `quota_key` ([String](../../sql-reference/data-types/string.md)) — The `quota key` specified in the [quotas](../../operations/quotas.md) setting (see `keyed`).
+-   `revision` ([UInt32](../../sql-reference/data-types/int-uint.md)) — ClickHouse revision.
+-   `ProfileEvents` ([Map(String, UInt64)](../../sql-reference/data-types/array.md)) — ProfileEvents that measure different metrics. The description of them could be found in the table [system.events](../../operations/system-tables/events.md#system_tables-events)
+-   `Settings` ([Map(String, String)](../../sql-reference/data-types/array.md)) — Settings that were changed when the client ran the query. To enable logging changes to settings, set the `log_query_settings` parameter to 1.
+-   `log_comment` ([String](../../sql-reference/data-types/string.md)) — Log comment. It can be set to arbitrary string no longer than [max_query_size](../../operations/settings/settings.md#settings-max_query_size). An empty string if it is not defined.
+-   `thread_ids` ([Array(UInt64)](../../sql-reference/data-types/array.md)) — Thread ids that are participating in query execution.
+-   `used_aggregate_functions` ([Array(String)](../../sql-reference/data-types/array.md)) — Canonical names of `aggregate functions`, which were used during query execution.
+-   `used_aggregate_function_combinators` ([Array(String)](../../sql-reference/data-types/array.md)) — Canonical names of `aggregate functions combinators`, which were used during query execution.
+-   `used_database_engines` ([Array(String)](../../sql-reference/data-types/array.md)) — Canonical names of `database engines`, which were used during query execution.
+-   `used_data_type_families` ([Array(String)](../../sql-reference/data-types/array.md)) — Canonical names of `data type families`, which were used during query execution.
+-   `used_dictionaries` ([Array(String)](../../sql-reference/data-types/array.md)) — Canonical names of `dictionaries`, which were used during query execution.
+-   `used_formats` ([Array(String)](../../sql-reference/data-types/array.md)) — Canonical names of `formats`, which were used during query execution.
+-   `used_functions` ([Array(String)](../../sql-reference/data-types/array.md)) — Canonical names of `functions`, which were used during query execution.
+-   `used_storages` ([Array(String)](../../sql-reference/data-types/array.md)) — Canonical names of `storages`, which were used during query execution.
+-   `used_table_functions` ([Array(String)](../../sql-reference/data-types/array.md)) — Canonical names of `table functions`, which were used during query execution.
+
+**Example**
+
+``` sql
+SELECT * FROM system.query_log WHERE type = 'QueryFinish' ORDER BY query_start_time DESC LIMIT 1 FORMAT Vertical;
+```
+
+``` text
+Row 1:
+──────
+type:                                  QueryFinish
+event_date:                            2021-11-03
+event_time:                            2021-11-03 16:13:54
+event_time_microseconds:               2021-11-03 16:13:54.953024
+query_start_time:                      2021-11-03 16:13:54
+query_start_time_microseconds:         2021-11-03 16:13:54.952325
+query_duration_ms:                     0
+read_rows:                             69
+read_bytes:                            6187
+written_rows:                          0
+written_bytes:                         0
+result_rows:                           69
+result_bytes:                          48256
+memory_usage:                          0
+current_database:                      default
+query:                                 DESCRIBE TABLE system.query_log
+formatted_query:
+normalized_query_hash:                 8274064835331539124
+query_kind:
+databases:                             []
+tables:                                []
+columns:                               []
+projections:                           []
+views:                                 []
+exception_code:                        0
+exception:
+stack_trace:
+is_initial_query:                      1
+user:                                  default
+query_id:                              7c28bbbb-753b-4eba-98b1-efcbe2b9bdf6
+address:                               ::ffff:127.0.0.1
+port:                                  40452
+initial_user:                          default
+initial_query_id:                      7c28bbbb-753b-4eba-98b1-efcbe2b9bdf6
+initial_address:                       ::ffff:127.0.0.1
+initial_port:                          40452
+initial_query_start_time:              2021-11-03 16:13:54
+initial_query_start_time_microseconds: 2021-11-03 16:13:54.952325
+interface:                             1
+os_user:                               sevirov
+client_hostname:                       clickhouse.ru-central1.internal
+client_name:                           ClickHouse
+client_revision:                       54449
+client_version_major:                  21
+client_version_minor:                  10
+client_version_patch:                  1
+http_method:                           0
+http_user_agent:
+http_referer:
+forwarded_for:
+quota_key:
+revision:                              54456
+log_comment:
+thread_ids:                            [30776,31174]
+ProfileEvents:                         {'Query':1,'NetworkSendElapsedMicroseconds':59,'NetworkSendBytes':2643,'SelectedRows':69,'SelectedBytes':6187,'ContextLock':9,'RWLockAcquiredReadLocks':1,'RealTimeMicroseconds':817,'UserTimeMicroseconds':427,'SystemTimeMicroseconds':212,'OSCPUVirtualTimeMicroseconds':639,'OSReadChars':894,'OSWriteChars':319}
+Settings:                              {'load_balancing':'random','max_memory_usage':'10000000000'}
+used_aggregate_functions:              []
+used_aggregate_function_combinators:   []
+used_database_engines:                 []
+used_data_type_families:               []
+used_dictionaries:                     []
+used_formats:                          []
+used_functions:                        []
+used_storages:                         []
+used_table_functions:                  []
+```
+
+**See Also**
+
+-   [system.query_thread_log](../../operations/system-tables/query_thread_log.md#system_tables-query_thread_log) — This table contains information about each query execution thread.
diff --git a/docs/en/reference/operations/system-tables/query_thread_log.md b/docs/en/reference/operations/system-tables/query_thread_log.md
new file mode 100644
index 00000000000..072a311b7db
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/query_thread_log.md
@@ -0,0 +1,119 @@
+# query_thread_log {#system_tables-query_thread_log}
+
+Contains information about threads that execute queries, for example, thread name, thread start time, duration of query processing.
+
+To start logging:
+
+1.  Configure parameters in the [query_thread_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-query_thread_log) section.
+2.  Set [log_query_threads](../../operations/settings/settings.md#settings-log-query-threads) to 1.
+
+The flushing period of data is set in `flush_interval_milliseconds` parameter of the [query_thread_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-query_thread_log) server settings section. To force flushing, use the [SYSTEM FLUSH LOGS](../../sql-reference/statements/system.md#query_language-system-flush_logs) query.
+
+ClickHouse does not delete data from the table automatically. See [Introduction](../../operations/system-tables/index.md#system-tables-introduction) for more details.
+
+You can use the [log_queries_probability](../../operations/settings/settings.md#log-queries-probability) setting to reduce the number of queries, registered in the `query_thread_log` table.
+
+Columns:
+
+-   `event_date` ([Date](../../sql-reference/data-types/date.md)) — The date when the thread has finished execution of the query.
+-   `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — The date and time when the thread has finished execution of the query.
+-   `event_time_microsecinds` ([DateTime](../../sql-reference/data-types/datetime.md)) — The date and time when the thread has finished execution of the query with microseconds precision.
+-   `query_start_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Start time of query execution.
+-   `query_start_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Start time of query execution with microsecond precision.
+-   `query_duration_ms` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Duration of query execution.
+-   `read_rows` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Number of read rows.
+-   `read_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Number of read bytes.
+-   `written_rows` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — For `INSERT` queries, the number of written rows. For other queries, the column value is 0.
+-   `written_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — For `INSERT` queries, the number of written bytes. For other queries, the column value is 0.
+-   `memory_usage` ([Int64](../../sql-reference/data-types/int-uint.md)) — The difference between the amount of allocated and freed memory in context of this thread.
+-   `peak_memory_usage` ([Int64](../../sql-reference/data-types/int-uint.md)) — The maximum difference between the amount of allocated and freed memory in context of this thread.
+-   `thread_name` ([String](../../sql-reference/data-types/string.md)) — Name of the thread.
+-   `thread_number` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Internal thread ID.
+-   `thread_id` ([Int32](../../sql-reference/data-types/int-uint.md)) — thread ID.
+-   `master_thread_id` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — OS initial ID of initial thread.
+-   `query` ([String](../../sql-reference/data-types/string.md)) — Query string.
+-   `is_initial_query` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Query type. Possible values:
+    -   1 — Query was initiated by the client.
+    -   0 — Query was initiated by another query for distributed query execution.
+-   `user` ([String](../../sql-reference/data-types/string.md)) — Name of the user who initiated the current query.
+-   `query_id` ([String](../../sql-reference/data-types/string.md)) — ID of the query.
+-   `address` ([IPv6](../../sql-reference/data-types/domains/ipv6.md)) — IP address that was used to make the query.
+-   `port` ([UInt16](../../sql-reference/data-types/int-uint.md#uint-ranges)) — The client port that was used to make the query.
+-   `initial_user` ([String](../../sql-reference/data-types/string.md)) — Name of the user who ran the initial query (for distributed query execution).
+-   `initial_query_id` ([String](../../sql-reference/data-types/string.md)) — ID of the initial query (for distributed query execution).
+-   `initial_address` ([IPv6](../../sql-reference/data-types/domains/ipv6.md)) — IP address that the parent query was launched from.
+-   `initial_port` ([UInt16](../../sql-reference/data-types/int-uint.md#uint-ranges)) — The client port that was used to make the parent query.
+-   `interface` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Interface that the query was initiated from. Possible values:
+    -   1 — TCP.
+    -   2 — HTTP.
+-   `os_user` ([String](../../sql-reference/data-types/string.md)) — OS’s username who runs [clickhouse-client](../../interfaces/cli.md).
+-   `client_hostname` ([String](../../sql-reference/data-types/string.md)) — Hostname of the client machine where the [clickhouse-client](../../interfaces/cli.md) or another TCP client is run.
+-   `client_name` ([String](../../sql-reference/data-types/string.md)) — The [clickhouse-client](../../interfaces/cli.md) or another TCP client name.
+-   `client_revision` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Revision of the [clickhouse-client](../../interfaces/cli.md) or another TCP client.
+-   `client_version_major` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Major version of the [clickhouse-client](../../interfaces/cli.md) or another TCP client.
+-   `client_version_minor` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Minor version of the [clickhouse-client](../../interfaces/cli.md) or another TCP client.
+-   `client_version_patch` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Patch component of the [clickhouse-client](../../interfaces/cli.md) or another TCP client version.
+-   `http_method` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — HTTP method that initiated the query. Possible values:
+    -   0 — The query was launched from the TCP interface.
+    -   1 — `GET` method was used.
+    -   2 — `POST` method was used.
+-   `http_user_agent` ([String](../../sql-reference/data-types/string.md)) — The `UserAgent` header passed in the HTTP request.
+-   `quota_key` ([String](../../sql-reference/data-types/string.md)) — The “quota key” specified in the [quotas](../../operations/quotas.md) setting (see `keyed`).
+-   `revision` ([UInt32](../../sql-reference/data-types/int-uint.md)) — ClickHouse revision.
+-   `ProfileEvents` ([Map(String, UInt64)](../../sql-reference/data-types/array.md)) — ProfileEvents that measure different metrics for this thread. The description of them could be found in the table [system.events](#system_tables-events).
+
+**Example**
+
+``` sql
+ SELECT * FROM system.query_thread_log LIMIT 1 \G
+```
+
+``` text
+Row 1:
+──────
+event_date:                    2020-09-11
+event_time:                    2020-09-11 10:08:17
+event_time_microseconds:       2020-09-11 10:08:17.134042
+query_start_time:              2020-09-11 10:08:17
+query_start_time_microseconds: 2020-09-11 10:08:17.063150
+query_duration_ms:             70
+read_rows:                     0
+read_bytes:                    0
+written_rows:                  1
+written_bytes:                 12
+memory_usage:                  4300844
+peak_memory_usage:             4300844
+thread_name:                   TCPHandler
+thread_id:                     638133
+master_thread_id:              638133
+query:                         INSERT INTO test1 VALUES
+is_initial_query:              1
+user:                          default
+query_id:                      50a320fd-85a8-49b8-8761-98a86bcbacef
+address:                       ::ffff:127.0.0.1
+port:                          33452
+initial_user:                  default
+initial_query_id:              50a320fd-85a8-49b8-8761-98a86bcbacef
+initial_address:               ::ffff:127.0.0.1
+initial_port:                  33452
+interface:                     1
+os_user:                       bharatnc
+client_hostname:               tower
+client_name:                   ClickHouse
+client_revision:               54437
+client_version_major:          20
+client_version_minor:          7
+client_version_patch:          2
+http_method:                   0
+http_user_agent:
+quota_key:
+revision:                      54440
+ProfileEvents:        {'Query':1,'SelectQuery':1,'ReadCompressedBytes':36,'CompressedReadBufferBlocks':1,'CompressedReadBufferBytes':10,'IOBufferAllocs':1,'IOBufferAllocBytes':89,'ContextLock':15,'RWLockAcquiredReadLocks':1}
+```
+
+**See Also**
+
+-   [system.query_log](../../operations/system-tables/query_log.md#system_tables-query_log) — Description of the `query_log` system table which contains common information about queries execution.
+-   [system.query_views_log](../../operations/system-tables/query_views_log.md#system_tables-query_views_log) — This table contains information about each view executed during a query.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/query_thread_log) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/query_views_log.md b/docs/en/reference/operations/system-tables/query_views_log.md
new file mode 100644
index 00000000000..5aa69522869
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/query_views_log.md
@@ -0,0 +1,86 @@
+# query_views_log {#system_tables-query_views_log}
+
+Contains information about the dependent views executed when running a query, for example, the view type or the execution time.
+
+To start logging:
+
+1. Configure parameters in the [query_views_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-query_views_log) section.
+2. Set [log_query_views](../../operations/settings/settings.md#settings-log-query-views) to 1.
+
+The flushing period of data is set in `flush_interval_milliseconds` parameter of the [query_views_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-query_views_log) server settings section. To force flushing, use the [SYSTEM FLUSH LOGS](../../sql-reference/statements/system.md#query_language-system-flush_logs) query.
+
+ClickHouse does not delete data from the table automatically. See [Introduction](../../operations/system-tables/index.md#system-tables-introduction) for more details.
+
+You can use the [log_queries_probability](../../operations/settings/settings.md#log-queries-probability) setting to reduce the number of queries, registered in the `query_views_log` table.
+
+Columns:
+
+-   `event_date` ([Date](../../sql-reference/data-types/date.md)) — The date when the last event of the view happened.
+-   `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — The date and time when the view finished execution.
+-   `event_time_microseconds` ([DateTime](../../sql-reference/data-types/datetime.md)) — The date and time when the view finished execution with microseconds precision.
+-   `view_duration_ms` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Duration of view execution (sum of its stages) in milliseconds.
+-   `initial_query_id` ([String](../../sql-reference/data-types/string.md)) — ID of the initial query (for distributed query execution).
+-   `view_name` ([String](../../sql-reference/data-types/string.md)) — Name of the view.
+-   `view_uuid` ([UUID](../../sql-reference/data-types/uuid.md)) — UUID of the view.
+-   `view_type` ([Enum8](../../sql-reference/data-types/enum.md)) — Type of the view. Values:
+    -   `'Default' = 1` — [Default views](../../sql-reference/statements/create/view.md#normal). Should not appear in this log.
+    -   `'Materialized' = 2` — [Materialized views](../../sql-reference/statements/create/view.md#materialized).
+    -   `'Live' = 3` — [Live views](../../sql-reference/statements/create/view.md#live-view).
+-   `view_query` ([String](../../sql-reference/data-types/string.md)) — The query executed by the view.
+-   `view_target` ([String](../../sql-reference/data-types/string.md)) — The name of the view target table.
+-   `read_rows` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Number of read rows.
+-   `read_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Number of read bytes.
+-   `written_rows` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Number of written rows.
+-   `written_bytes` ([UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Number of written bytes.
+-   `peak_memory_usage` ([Int64](../../sql-reference/data-types/int-uint.md)) — The maximum difference between the amount of allocated and freed memory in context of this view.
+-   `ProfileEvents` ([Map(String, UInt64)](../../sql-reference/data-types/array.md)) — ProfileEvents that measure different metrics. The description of them could be found in the table [system.events](../../operations/system-tables/events.md#system_tables-events).
+-   `status` ([Enum8](../../sql-reference/data-types/enum.md)) — Status of the view. Values:
+    -   `'QueryStart' = 1` — Successful start the view execution. Should not appear.
+    -   `'QueryFinish' = 2` — Successful end of the view execution.
+    -   `'ExceptionBeforeStart' = 3` — Exception before the start of the view execution.
+    -   `'ExceptionWhileProcessing' = 4` — Exception during the view execution.
+-   `exception_code` ([Int32](../../sql-reference/data-types/int-uint.md)) — Code of an exception.
+-   `exception` ([String](../../sql-reference/data-types/string.md)) — Exception message.
+-   `stack_trace` ([String](../../sql-reference/data-types/string.md)) — [Stack trace](https://en.wikipedia.org/wiki/Stack_trace). An empty string, if the query was completed successfully.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT * FROM system.query_views_log LIMIT 1 \G;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+event_date:              2021-06-22
+event_time:              2021-06-22 13:23:07
+event_time_microseconds: 2021-06-22 13:23:07.738221
+view_duration_ms:        0
+initial_query_id:        c3a1ac02-9cad-479b-af54-9e9c0a7afd70
+view_name:               default.matview_inner
+view_uuid:               00000000-0000-0000-0000-000000000000
+view_type:               Materialized
+view_query:              SELECT * FROM default.table_b
+view_target:             default.`.inner.matview_inner`
+read_rows:               4
+read_bytes:              64
+written_rows:            2
+written_bytes:           32
+peak_memory_usage:       4196188
+ProfileEvents:           {'FileOpen':2,'WriteBufferFromFileDescriptorWrite':2,'WriteBufferFromFileDescriptorWriteBytes':187,'IOBufferAllocs':3,'IOBufferAllocBytes':3145773,'FunctionExecute':3,'DiskWriteElapsedMicroseconds':13,'InsertedRows':2,'InsertedBytes':16,'SelectedRows':4,'SelectedBytes':48,'ContextLock':16,'RWLockAcquiredReadLocks':1,'RealTimeMicroseconds':698,'SoftPageFaults':4,'OSReadChars':463}
+status:                  QueryFinish
+exception_code:          0
+exception:
+stack_trace:
+```
+
+**See Also**
+
+-   [system.query_log](../../operations/system-tables/query_log.md#system_tables-query_log) — Description of the `query_log` system table which contains common information about queries execution.
+-   [system.query_thread_log](../../operations/system-tables/query_thread_log.md#system_tables-query_thread_log) — This table contains information about each query execution thread.
+
+[Original article](https://clickhouse.com/docs/en/operations/system_tables/query_thread_log) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/quota_limits.md b/docs/en/reference/operations/system-tables/quota_limits.md
new file mode 100644
index 00000000000..e1873ecfa92
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/quota_limits.md
@@ -0,0 +1,21 @@
+# quota_limits {#system_tables-quota_limits}
+
+Contains information about maximums for all intervals of all quotas. Any number of rows or zero can correspond to one quota.
+
+Columns:
+- `quota_name` ([String](../../sql-reference/data-types/string.md)) — Quota name.
+- `duration` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Length of the time interval for calculating resource consumption, in seconds.
+- `is_randomized_interval` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Logical value. It shows whether the interval is randomized. Interval always starts at the same time if it is not randomized. For example, an interval of 1 minute always starts at an integer number of minutes (i.e. it can start at 11:20:00, but it never starts at 11:20:01), an interval of one day always starts at midnight UTC. If interval is randomized, the very first interval starts at random time, and subsequent intervals starts one by one. Values:
+- `0` — Interval is not randomized.
+- `1` — Interval is randomized.
+- `max_queries` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of queries.
+- `max_query_selects` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of select queries.
+- `max_query_inserts` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of insert queries.
+- `max_errors` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of errors.
+- `max_result_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of result rows.
+- `max_result_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of RAM volume in bytes used to store a queries result.
+- `max_read_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of rows read from all tables and table functions participated in queries.
+- `max_read_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of bytes read from all tables and table functions participated in queries.
+- `max_execution_time` ([Nullable](../../sql-reference/data-types/nullable.md)([Float64](../../sql-reference/data-types/float.md))) — Maximum of the query execution time, in seconds.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/quota_limits) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/quota_usage.md b/docs/en/reference/operations/system-tables/quota_usage.md
new file mode 100644
index 00000000000..ad9f9b8c44f
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/quota_usage.md
@@ -0,0 +1,32 @@
+# quota_usage {#system_tables-quota_usage}
+
+Quota usage by the current user: how much is used and how much is left.
+
+Columns:
+- `quota_name` ([String](../../sql-reference/data-types/string.md)) — Quota name.
+- `quota_key`([String](../../sql-reference/data-types/string.md)) — Key value. For example, if keys = \[`ip address`\], `quota_key` may have a value ‘192.168.1.1’.
+- `start_time`([Nullable](../../sql-reference/data-types/nullable.md)([DateTime](../../sql-reference/data-types/datetime.md))) — Start time for calculating resource consumption.
+- `end_time`([Nullable](../../sql-reference/data-types/nullable.md)([DateTime](../../sql-reference/data-types/datetime.md))) — End time for calculating resource consumption.
+- `duration` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Length of the time interval for calculating resource consumption, in seconds.
+- `queries` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of requests on this interval.
+- `query_selects` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of select requests on this interval.
+- `query_inserts` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of insert requests on this interval.
+- `max_queries` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of requests.
+- `errors` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The number of queries that threw an exception.
+- `max_errors` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of errors.
+- `result_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of rows given as a result.
+- `max_result_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of result rows.
+- `result_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — RAM volume in bytes used to store a queries result.
+- `max_result_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum RAM volume used to store a queries result, in bytes.
+- `read_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of source rows read from tables for running the query on all remote servers.
+- `max_read_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of rows read from all tables and table functions participated in queries.
+- `read_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of bytes read from all tables and table functions participated in queries.
+- `max_read_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum of bytes read from all tables and table functions.
+- `execution_time` ([Nullable](../../sql-reference/data-types/nullable.md)([Float64](../../sql-reference/data-types/float.md))) — The total query execution time, in seconds (wall time).
+- `max_execution_time` ([Nullable](../../sql-reference/data-types/nullable.md)([Float64](../../sql-reference/data-types/float.md))) — Maximum of query execution time.
+
+## See Also {#see-also}
+
+-   [SHOW QUOTA](../../sql-reference/statements/show.md#show-quota-statement)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/quota_usage) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/quotas.md b/docs/en/reference/operations/system-tables/quotas.md
new file mode 100644
index 00000000000..0a435919b14
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/quotas.md
@@ -0,0 +1,28 @@
+# quotas {#system_tables-quotas}
+
+Contains information about [quotas](../../operations/system-tables/quotas.md).
+
+Columns:
+- `name` ([String](../../sql-reference/data-types/string.md)) — Quota name.
+- `id` ([UUID](../../sql-reference/data-types/uuid.md)) — Quota ID.
+- `storage`([String](../../sql-reference/data-types/string.md)) — Storage of quotas. Possible value: “users.xml” if a quota configured in the users.xml file, “disk” if a quota configured by an SQL-query.
+- `keys` ([Array](../../sql-reference/data-types/array.md)([Enum8](../../sql-reference/data-types/enum.md))) — Key specifies how the quota should be shared. If two connections use the same quota and key, they share the same amounts of resources. Values:
+    - `[]` — All users share the same quota.
+    - `['user_name']` — Connections with the same user name share the same quota.
+    - `['ip_address']` — Connections from the same IP share the same quota.
+    - `['client_key']` — Connections with the same key share the same quota. A key must be explicitly provided by a client. When using [clickhouse-client](../../interfaces/cli.md), pass a key value in the `--quota_key` parameter, or use the `quota_key` parameter in the client configuration file. When using HTTP interface, use the `X-ClickHouse-Quota` header.
+    - `['user_name', 'client_key']` — Connections with the same `client_key` share the same quota. If a key isn’t provided by a client, the qouta is tracked for `user_name`.
+    - `['client_key', 'ip_address']` — Connections with the same `client_key` share the same quota. If a key isn’t provided by a client, the qouta is tracked for `ip_address`.
+- `durations` ([Array](../../sql-reference/data-types/array.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Time interval lengths in seconds.
+- `apply_to_all` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Logical value. It shows which users the quota is applied to. Values:
+    - `0` — The quota applies to users specify in the `apply_to_list`.
+    - `1` — The quota applies to all users except those listed in `apply_to_except`.
+- `apply_to_list` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — List of user names/[roles](../../operations/access-rights.md#role-management) that the quota should be applied to.
+- `apply_to_except` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — List of user names/roles that the quota should not apply to.
+
+## See Also {#see-also}
+
+-   [SHOW QUOTAS](../../sql-reference/statements/show.md#show-quotas-statement)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/quotas) <!--hide-->
+
diff --git a/docs/en/reference/operations/system-tables/quotas_usage.md b/docs/en/reference/operations/system-tables/quotas_usage.md
new file mode 100644
index 00000000000..43811a75187
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/quotas_usage.md
@@ -0,0 +1,35 @@
+# quotas_usage {#system_tables-quotas_usage}
+
+Quota usage by all users.
+
+Columns:
+- `quota_name` ([String](../../sql-reference/data-types/string.md)) — Quota name.
+- `quota_key` ([String](../../sql-reference/data-types/string.md)) — Key value.
+- `is_current` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Quota usage for current user.
+- `start_time` ([Nullable](../../sql-reference/data-types/nullable.md)([DateTime](../../sql-reference/data-types/datetime.md)))) — Start time for calculating resource consumption.
+- `end_time` ([Nullable](../../sql-reference/data-types/nullable.md)([DateTime](../../sql-reference/data-types/datetime.md)))) — End time for calculating resource consumption.
+- `duration` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt32](../../sql-reference/data-types/int-uint.md))) — Length of the time interval for calculating resource consumption, in seconds.
+- `queries` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of requests in this interval.
+- `max_queries` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of requests.
+- `query_selects` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of select requests in this interval.
+- `max_query_selects` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of select requests.
+- `query_inserts` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of insert requests in this interval.
+- `max_query_inserts` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of insert requests.
+- `errors` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The number of queries that threw an exception.
+- `max_errors` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of errors.
+- `result_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of rows given as a result.
+- `max_result_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum of source rows read from tables.
+- `result_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — RAM volume in bytes used to store a queries result.
+- `max_result_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum RAM volume used to store a queries result, in bytes.
+- `read_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md)))) — The total number of source rows read from tables for running the query on all remote servers.
+- `max_read_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum number of rows read from all tables and table functions participated in queries.
+- `read_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — The total number of bytes read from all tables and table functions participated in queries.
+- `max_read_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) — Maximum of bytes read from all tables and table functions.
+- `execution_time` ([Nullable](../../sql-reference/data-types/nullable.md)([Float64](../../sql-reference/data-types/float.md))) — The total query execution time, in seconds (wall time).
+- `max_execution_time` ([Nullable](../../sql-reference/data-types/nullable.md)([Float64](../../sql-reference/data-types/float.md))) — Maximum of query execution time.
+
+## See Also {#see-also}
+
+-   [SHOW QUOTA](../../sql-reference/statements/show.md#show-quota-statement)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/quotas_usage) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/replicas.md b/docs/en/reference/operations/system-tables/replicas.md
new file mode 100644
index 00000000000..6ec0f184e15
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/replicas.md
@@ -0,0 +1,132 @@
+# replicas {#system_tables-replicas}
+
+Contains information and status for replicated tables residing on the local server.
+This table can be used for monitoring. The table contains a row for every Replicated\* table.
+
+Example:
+
+``` sql
+SELECT *
+FROM system.replicas
+WHERE table = 'test_table'
+FORMAT Vertical
+```
+
+``` text
+Query id: dc6dcbcb-dc28-4df9-ae27-4354f5b3b13e
+
+Row 1:
+───────
+database:                    db
+table:                       test_table
+engine:                      ReplicatedMergeTree
+is_leader:                   1
+can_become_leader:           1
+is_readonly:                 0
+is_session_expired:          0
+future_parts:                0
+parts_to_check:              0
+zookeeper_path:              /test/test_table
+replica_name:                r1
+replica_path:                /test/test_table/replicas/r1
+columns_version:             -1
+queue_size:                  27
+inserts_in_queue:            27
+merges_in_queue:             0
+part_mutations_in_queue:     0
+queue_oldest_time:           2021-10-12 14:48:48
+inserts_oldest_time:         2021-10-12 14:48:48
+merges_oldest_time:          1970-01-01 03:00:00
+part_mutations_oldest_time:  1970-01-01 03:00:00
+oldest_part_to_get:          1_17_17_0
+oldest_part_to_merge_to:     
+oldest_part_to_mutate_to:    
+log_max_index:               206
+log_pointer:                 207
+last_queue_update:           2021-10-12 14:50:08
+absolute_delay:              99
+total_replicas:              5
+active_replicas:             5
+last_queue_update_exception: 
+zookeeper_exception:         
+replica_is_active:           {'r1':1,'r2':1}
+```
+
+Columns:
+
+-   `database` (`String`) - Database name
+-   `table` (`String`) - Table name
+-   `engine` (`String`) - Table engine name
+-   `is_leader` (`UInt8`) - Whether the replica is the leader.
+    Multiple replicas can be leaders at the same time. A replica can be prevented from becoming a leader using the `merge_tree` setting `replicated_can_become_leader`. The leaders are responsible for scheduling background merges.
+    Note that writes can be performed to any replica that is available and has a session in ZK, regardless of whether it is a leader.
+-   `can_become_leader` (`UInt8`) - Whether the replica can be a leader.
+-   `is_readonly` (`UInt8`) - Whether the replica is in read-only mode.
+    This mode is turned on if the config does not have sections with ZooKeeper, if an unknown error occurred when reinitializing sessions in ZooKeeper, and during session reinitialization in ZooKeeper.
+-   `is_session_expired` (`UInt8`) - the session with ZooKeeper has expired. Basically the same as `is_readonly`.
+-   `future_parts` (`UInt32`) - The number of data parts that will appear as the result of INSERTs or merges that haven’t been done yet.
+-   `parts_to_check` (`UInt32`) - The number of data parts in the queue for verification. A part is put in the verification queue if there is suspicion that it might be damaged.
+-   `zookeeper_path` (`String`) - Path to table data in ZooKeeper.
+-   `replica_name` (`String`) - Replica name in ZooKeeper. Different replicas of the same table have different names.
+-   `replica_path` (`String`) - Path to replica data in ZooKeeper. The same as concatenating ‘zookeeper_path/replicas/replica_path’.
+-   `columns_version` (`Int32`) - Version number of the table structure. Indicates how many times ALTER was performed. If replicas have different versions, it means some replicas haven’t made all of the ALTERs yet.
+-   `queue_size` (`UInt32`) - Size of the queue for operations waiting to be performed. Operations include inserting blocks of data, merges, and certain other actions. It usually coincides with `future_parts`.
+-   `inserts_in_queue` (`UInt32`) - Number of inserts of blocks of data that need to be made. Insertions are usually replicated fairly quickly. If this number is large, it means something is wrong.
+-   `merges_in_queue` (`UInt32`) - The number of merges waiting to be made. Sometimes merges are lengthy, so this value may be greater than zero for a long time.
+-   `part_mutations_in_queue` (`UInt32`) - The number of mutations waiting to be made.
+-   `queue_oldest_time` (`DateTime`) - If `queue_size` greater than 0, shows when the oldest operation was added to the queue.
+-   `inserts_oldest_time` (`DateTime`) - See `queue_oldest_time`
+-   `merges_oldest_time` (`DateTime`) - See `queue_oldest_time`
+-   `part_mutations_oldest_time` (`DateTime`) - See `queue_oldest_time`
+
+The next 4 columns have a non-zero value only where there is an active session with ZK.
+
+-   `log_max_index` (`UInt64`) - Maximum entry number in the log of general activity.
+-   `log_pointer` (`UInt64`) - Maximum entry number in the log of general activity that the replica copied to its execution queue, plus one. If `log_pointer` is much smaller than `log_max_index`, something is wrong.
+-   `last_queue_update` (`DateTime`) - When the queue was updated last time.
+-   `absolute_delay` (`UInt64`) - How big lag in seconds the current replica has.
+-   `total_replicas` (`UInt8`) - The total number of known replicas of this table.
+-   `active_replicas` (`UInt8`) - The number of replicas of this table that have a session in ZooKeeper (i.e., the number of functioning replicas).
+-   `last_queue_update_exception` (`String`) - When the queue contains broken entries. Especially important when ClickHouse breaks backward compatibility between versions and log entries written by newer versions aren't parseable by old versions.
+-   `zookeeper_exception` (`String`) - The last exception message, got if the error happened when fetching the info from ZooKeeper. 
+-   `replica_is_active` ([Map(String, UInt8)](../../sql-reference/data-types/map.md)) — Map between replica name and is replica active.
+
+If you request all the columns, the table may work a bit slowly, since several reads from ZooKeeper are made for each row.
+If you do not request the last 4 columns (log_max_index, log_pointer, total_replicas, active_replicas), the table works quickly.
+
+For example, you can check that everything is working correctly like this:
+
+``` sql
+SELECT
+    database,
+    table,
+    is_leader,
+    is_readonly,
+    is_session_expired,
+    future_parts,
+    parts_to_check,
+    columns_version,
+    queue_size,
+    inserts_in_queue,
+    merges_in_queue,
+    log_max_index,
+    log_pointer,
+    total_replicas,
+    active_replicas
+FROM system.replicas
+WHERE
+       is_readonly
+    OR is_session_expired
+    OR future_parts > 20
+    OR parts_to_check > 10
+    OR queue_size > 20
+    OR inserts_in_queue > 10
+    OR log_max_index - log_pointer > 10
+    OR total_replicas < 2
+    OR active_replicas < total_replicas
+```
+
+If this query does not return anything, it means that everything is fine.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/replicas) <!--hide-->
+
diff --git a/docs/en/reference/operations/system-tables/replicated_fetches.md b/docs/en/reference/operations/system-tables/replicated_fetches.md
new file mode 100644
index 00000000000..438d1572109
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/replicated_fetches.md
@@ -0,0 +1,70 @@
+# replicated_fetches {#system_tables-replicated_fetches}
+
+Contains information about currently running background fetches.
+
+Columns:
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) — Name of the database.
+
+-   `table` ([String](../../sql-reference/data-types/string.md)) — Name of the table.
+
+-   `elapsed` ([Float64](../../sql-reference/data-types/float.md)) — The time elapsed (in seconds) since showing currently running background fetches started.
+
+-   `progress` ([Float64](../../sql-reference/data-types/float.md)) — The percentage of completed work from 0 to 1.
+
+-   `result_part_name` ([String](../../sql-reference/data-types/string.md)) — The name of the part that will be formed as the result of showing currently running background fetches.
+
+-   `result_part_path` ([String](../../sql-reference/data-types/string.md)) — Absolute path to the part that will be formed as the result of showing currently running background fetches.
+
+-   `partition_id` ([String](../../sql-reference/data-types/string.md)) — ID of the partition.
+
+-   `total_size_bytes_compressed` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The total size (in bytes) of the compressed data in the result part.
+
+-   `bytes_read_compressed` ([UInt64](../../sql-reference/data-types/int-uint.md)) — The number of compressed bytes read from the result part.
+
+-   `source_replica_path` ([String](../../sql-reference/data-types/string.md)) — Absolute path to the source replica.
+
+-   `source_replica_hostname` ([String](../../sql-reference/data-types/string.md)) — Hostname of the source replica.
+
+-   `source_replica_port` ([UInt16](../../sql-reference/data-types/int-uint.md)) — Port number of the source replica.
+
+-   `interserver_scheme` ([String](../../sql-reference/data-types/string.md)) — Name of the interserver scheme.
+
+-   `URI` ([String](../../sql-reference/data-types/string.md)) — Uniform resource identifier.
+
+-   `to_detached` ([UInt8](../../sql-reference/data-types/int-uint.md)) — The flag indicates whether the currently running background fetch is being performed using the `TO DETACHED` expression.
+
+-   `thread_id` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Thread identifier.
+
+**Example**
+
+``` sql
+SELECT * FROM system.replicated_fetches LIMIT 1 FORMAT Vertical;
+```
+
+``` text
+Row 1:
+──────
+database:                    default
+table:                       t
+elapsed:                     7.243039876
+progress:                    0.41832135995612835
+result_part_name:            all_0_0_0
+result_part_path:            /var/lib/clickhouse/store/700/70080a04-b2de-4adf-9fa5-9ea210e81766/all_0_0_0/
+partition_id:                all
+total_size_bytes_compressed: 1052783726
+bytes_read_compressed:       440401920
+source_replica_path:         /clickhouse/test/t/replicas/1
+source_replica_hostname:     node1
+source_replica_port:         9009
+interserver_scheme:          http
+URI:                         http://node1:9009/?endpoint=DataPartsExchange%3A%2Fclickhouse%2Ftest%2Ft%2Freplicas%2F1&part=all_0_0_0&client_protocol_version=4&compress=false
+to_detached:                 0
+thread_id:                   54
+```
+
+**See Also**
+
+-   [Managing ReplicatedMergeTree Tables](../../sql-reference/statements/system/#query-language-system-replicated)
+
+[Original article](https://clickhouse.com/docs/en/operations/system_tables/replicated_fetches) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/replication_queue.md b/docs/en/reference/operations/system-tables/replication_queue.md
new file mode 100644
index 00000000000..a8a51162dae
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/replication_queue.md
@@ -0,0 +1,91 @@
+# replication_queue {#system_tables-replication_queue}
+
+Contains information about tasks from replication queues stored in ZooKeeper for tables in the `ReplicatedMergeTree` family.
+
+Columns:
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) — Name of the database.
+
+-   `table` ([String](../../sql-reference/data-types/string.md)) — Name of the table.
+
+-   `replica_name` ([String](../../sql-reference/data-types/string.md)) — Replica name in ZooKeeper. Different replicas of the same table have different names.
+
+-   `position` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Position of the task in the queue.
+
+-   `node_name` ([String](../../sql-reference/data-types/string.md)) — Node name in ZooKeeper.
+
+-   `type` ([String](../../sql-reference/data-types/string.md)) — Type of the task in the queue, one of:
+
+    -   `GET_PART` — Get the part from another replica.
+    -   `ATTACH_PART` — Attach the part, possibly from our own replica (if found in the `detached` folder). You may think of it as a `GET_PART` with some optimizations as they're nearly identical.
+    -   `MERGE_PARTS` — Merge the parts.
+    -   `DROP_RANGE` — Delete the parts in the specified partition in the specified number range.
+    -   `CLEAR_COLUMN` — NOTE: Deprecated. Drop specific column from specified partition.
+    -   `CLEAR_INDEX` — NOTE: Deprecated. Drop specific index from specified partition.
+    -   `REPLACE_RANGE` — Drop a certain range of parts and replace them with new ones.
+    -   `MUTATE_PART` — Apply one or several mutations to the part.
+    -   `ALTER_METADATA` — Apply alter modification according to global /metadata and /columns paths.
+
+-   `create_time` ([Datetime](../../sql-reference/data-types/datetime.md)) — Date and time when the task was submitted for execution.
+
+-   `required_quorum` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The number of replicas waiting for the task to complete with confirmation of completion. This column is only relevant for the `GET_PARTS` task.
+
+-   `source_replica` ([String](../../sql-reference/data-types/string.md)) — Name of the source replica.
+
+-   `new_part_name` ([String](../../sql-reference/data-types/string.md)) — Name of the new part.
+
+-   `parts_to_merge` ([Array](../../sql-reference/data-types/array.md) ([String](../../sql-reference/data-types/string.md))) — Names of parts to merge or update.
+
+-   `is_detach` ([UInt8](../../sql-reference/data-types/int-uint.md)) — The flag indicates whether the `DETACH_PARTS` task is in the queue.
+
+-   `is_currently_executing` ([UInt8](../../sql-reference/data-types/int-uint.md)) — The flag indicates whether a specific task is being performed right now.
+
+-   `num_tries` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The number of failed attempts to complete the task.
+
+-   `last_exception` ([String](../../sql-reference/data-types/string.md)) — Text message about the last error that occurred (if any).
+
+-   `last_attempt_time` ([Datetime](../../sql-reference/data-types/datetime.md)) — Date and time when the task was last attempted.
+
+-   `num_postponed` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The number of postponed tasks.
+
+-   `postpone_reason` ([String](../../sql-reference/data-types/string.md)) — The reason why the task was postponed.
+
+-   `last_postpone_time` ([Datetime](../../sql-reference/data-types/datetime.md)) — Date and time when the task was last postponed.
+
+-   `merge_type` ([String](../../sql-reference/data-types/string.md)) — Type of the current merge. Empty if it's a mutation.
+
+**Example**
+
+``` sql
+SELECT * FROM system.replication_queue LIMIT 1 FORMAT Vertical;
+```
+
+``` text
+Row 1:
+──────
+database:               merge
+table:                  visits_v2
+replica_name:           mtgiga001-1t
+position:               15
+node_name:              queue-0009325559
+type:                   MERGE_PARTS
+create_time:            2020-12-07 14:04:21
+required_quorum:        0
+source_replica:         mtgiga001-1t
+new_part_name:          20201130_121373_121384_2
+parts_to_merge:         ['20201130_121373_121378_1','20201130_121379_121379_0','20201130_121380_121380_0','20201130_121381_121381_0','20201130_121382_121382_0','20201130_121383_121383_0','20201130_121384_121384_0']
+is_detach:              0
+is_currently_executing: 0
+num_tries:              36
+last_exception:         Code: 226, e.displayText() = DB::Exception: Marks file '/opt/clickhouse/data/merge/visits_v2/tmp_fetch_20201130_121373_121384_2/CounterID.mrk' does not exist (version 20.8.7.15 (official build))
+last_attempt_time:      2020-12-08 17:35:54
+num_postponed:          0
+postpone_reason:
+last_postpone_time:     1970-01-01 03:00:00
+```
+
+**See Also**
+
+-   [Managing ReplicatedMergeTree Tables](../../sql-reference/statements/system.md#query-language-system-replicated)
+
+[Original article](https://clickhouse.com/docs/en/operations/system_tables/replication_queue) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/role-grants.md b/docs/en/reference/operations/system-tables/role-grants.md
new file mode 100644
index 00000000000..cb0c5bf0b0b
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/role-grants.md
@@ -0,0 +1,21 @@
+# role_grants 
+
+Contains the role grants for users and roles. To add entries to this table, use `GRANT role TO user`.
+
+Columns:
+
+- `user_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — User name.
+
+- `role_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Role name.
+
+- `granted_role_name` ([String](../../sql-reference/data-types/string.md)) — Name of role granted to the `role_name` role. To grant one role to another one use `GRANT role1 TO role2`.
+
+- `granted_role_is_default` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Flag that shows whether `granted_role` is a default role. Possible values:
+    -   1 — `granted_role` is a default role.
+    -   0 — `granted_role` is not a default role.
+
+- `with_admin_option` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Flag that shows whether `granted_role` is a role with [ADMIN OPTION](../../sql-reference/statements/grant.md#admin-option-privilege) privilege. Possible values:
+    -   1 — The role has `ADMIN OPTION` privilege.
+    -   0 — The role without `ADMIN OPTION` privilege.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/role-grants) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/roles.md b/docs/en/reference/operations/system-tables/roles.md
new file mode 100644
index 00000000000..1f8fe349c7f
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/roles.md
@@ -0,0 +1,15 @@
+# roles {#system_tables-roles}
+
+Contains information about configured [roles](../../operations/access-rights.md#role-management).
+
+Columns:
+
+- `name` ([String](../../sql-reference/data-types/string.md)) — Role name.
+- `id` ([UUID](../../sql-reference/data-types/uuid.md)) — Role ID.
+- `storage` ([String](../../sql-reference/data-types/string.md)) — Path to the storage of roles. Configured in the `access_control_path` parameter.
+
+## See Also {#see-also}
+
+-   [SHOW ROLES](../../sql-reference/statements/show.md#show-roles-statement)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/roles) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/row_policies.md b/docs/en/reference/operations/system-tables/row_policies.md
new file mode 100644
index 00000000000..2bff037751b
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/row_policies.md
@@ -0,0 +1,34 @@
+# row_policies {#system_tables-row_policies}
+
+Contains filters for one particular table, as well as a list of roles and/or users which should use this row policy.
+
+Columns:
+-    `name` ([String](../../sql-reference/data-types/string.md)) — Name of a row policy.
+
+-    `short_name` ([String](../../sql-reference/data-types/string.md)) — Short name of a row policy. Names of row policies are compound, for example: myfilter ON mydb.mytable. Here "myfilter ON mydb.mytable" is the name of the row policy, "myfilter" is it's short name.
+
+-    `database` ([String](../../sql-reference/data-types/string.md)) — Database name.
+
+-    `table` ([String](../../sql-reference/data-types/string.md)) — Table name.
+
+-    `id` ([UUID](../../sql-reference/data-types/uuid.md)) — Row policy ID.
+
+-    `storage` ([String](../../sql-reference/data-types/string.md)) — Name of the directory where the row policy is stored.
+
+-    `select_filter` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Condition which is used to filter rows.
+
+-    `is_restrictive` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether the row policy restricts access to rows, see [CREATE ROW POLICY](../../sql-reference/statements/create/row-policy.md#create-row-policy-as). Value:
+- `0` — The row policy is defined with `AS PERMISSIVE` clause.
+- `1` — The row policy is defined with `AS RESTRICTIVE` clause.
+
+-    `apply_to_all` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows that the row policies set for all roles and/or users.
+
+-    `apply_to_list` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — List of the roles and/or users to which the row policies is applied.
+
+-    `apply_to_except` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — The row policies is applied to all roles and/or users excepting of the listed ones.
+
+## See Also {#see-also}
+
+-   [SHOW POLICIES](../../sql-reference/statements/show.md#show-policies-statement)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/row_policies) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/session_log.md b/docs/en/reference/operations/system-tables/session_log.md
new file mode 100644
index 00000000000..9ee7e294bfd
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/session_log.md
@@ -0,0 +1,77 @@
+# session_log {#system_tables-session_log}
+
+Contains information about all successful and failed login and logout events.
+
+Columns:
+
+-   `type` ([Enum8](../../sql-reference/data-types/enum.md)) — Login/logout result. Possible values:
+    -   `LoginFailure` — Login error.
+    -   `LoginSuccess` — Successful login.
+    -   `Logout` — Logout from the system.
+-   `auth_id` ([UUID](../../sql-reference/data-types/uuid.md)) — Authentication ID, which is a UUID that is automatically generated each time user logins.
+-   `session_id` ([String](../../sql-reference/data-types/string.md)) — Session ID that is passed by client via [HTTP](../../interfaces/http.md) interface.
+-   `event_date` ([Date](../../sql-reference/data-types/date.md)) — Login/logout date.
+-   `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Login/logout time.
+-   `event_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Login/logout starting time with microseconds precision.
+-   `user` ([String](../../sql-reference/data-types/string.md)) — User name.
+-   `auth_type` ([Enum8](../../sql-reference/data-types/enum.md)) — The authentication type. Possible values:
+    -   `NO_PASSWORD`
+    -   `PLAINTEXT_PASSWORD`
+    -   `SHA256_PASSWORD`
+    -   `DOUBLE_SHA1_PASSWORD`
+    -   `LDAP`
+    -   `KERBEROS`
+-   `profiles` ([Array](../../sql-reference/data-types/array.md)([LowCardinality(String)](../../sql-reference/data-types/lowcardinality.md))) — The list of profiles set for all roles and/or users.
+-   `roles` ([Array](../../sql-reference/data-types/array.md)([LowCardinality(String)](../../sql-reference/data-types/lowcardinality.md))) — The list of roles to which the profile is applied.
+-   `settings` ([Array](../../sql-reference/data-types/array.md)([Tuple](../../sql-reference/data-types/tuple.md)([LowCardinality(String)](../../sql-reference/data-types/lowcardinality.md), [String](../../sql-reference/data-types/string.md)))) — Settings that were changed when the client logged in/out.
+-   `client_address` ([IPv6](../../sql-reference/data-types/domains/ipv6.md)) — The IP address that was used to log in/out.
+-   `client_port` ([UInt16](../../sql-reference/data-types/int-uint.md)) — The client port that was used to log in/out.
+-   `interface` ([Enum8](../../sql-reference/data-types/enum.md)) — The interface from which the login was initiated. Possible values:
+    -   `TCP`
+    -   `HTTP`
+    -   `gRPC`
+    -   `MySQL`
+    -   `PostgreSQL`
+-   `client_hostname` ([String](../../sql-reference/data-types/string.md)) — The hostname of the client machine where the [clickhouse-client](../../interfaces/cli.md) or another TCP client is run.
+-   `client_name` ([String](../../sql-reference/data-types/string.md)) — The `clickhouse-client` or another TCP client name.
+-   `client_revision` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Revision of the `clickhouse-client` or another TCP client.
+-   `client_version_major` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The major version of the `clickhouse-client` or another TCP client.
+-   `client_version_minor` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The minor version of the `clickhouse-client` or another TCP client.
+-   `client_version_patch` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Patch component of the `clickhouse-client` or another TCP client version.
+-   `failure_reason` ([String](../../sql-reference/data-types/string.md)) — The exception message containing the reason for the login/logout failure.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT * FROM system.session_log LIMIT 1 FORMAT Vertical;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+type:                    LoginSuccess
+auth_id:                 45e6bd83-b4aa-4a23-85e6-bd83b4aa1a23
+session_id:
+event_date:              2021-10-14
+event_time:              2021-10-14 20:33:52
+event_time_microseconds: 2021-10-14 20:33:52.104247
+user:                    default
+auth_type:               PLAINTEXT_PASSWORD
+profiles:                ['default']
+roles:                   []
+settings:                [('load_balancing','random'),('max_memory_usage','10000000000')]
+client_address:          ::ffff:127.0.0.1
+client_port:             38490
+interface:               TCP
+client_hostname:
+client_name:             ClickHouse client
+client_revision:         54449
+client_version_major:    21
+client_version_minor:    10
+client_version_patch:    0
+failure_reason:
+```
diff --git a/docs/en/reference/operations/system-tables/settings.md b/docs/en/reference/operations/system-tables/settings.md
new file mode 100644
index 00000000000..ce6f3cd4724
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/settings.md
@@ -0,0 +1,53 @@
+# settings {#system-tables-system-settings}
+
+Contains information about session settings for current user.
+
+Columns:
+
+-   `name` ([String](../../sql-reference/data-types/string.md)) — Setting name.
+-   `value` ([String](../../sql-reference/data-types/string.md)) — Setting value.
+-   `changed` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether a setting is changed from its default value.
+-   `description` ([String](../../sql-reference/data-types/string.md)) — Short setting description.
+-   `min` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Minimum value of the setting, if any is set via [constraints](../../operations/settings/constraints-on-settings.md#constraints-on-settings). If the setting has no minimum value, contains [NULL](../../sql-reference/syntax.md#null-literal).
+-   `max` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Maximum value of the setting, if any is set via [constraints](../../operations/settings/constraints-on-settings.md#constraints-on-settings). If the setting has no maximum value, contains [NULL](../../sql-reference/syntax.md#null-literal).
+-   `readonly` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether the current user can change the setting:
+    -   `0` — Current user can change the setting.
+    -   `1` — Current user can’t change the setting.
+
+**Example**
+
+The following example shows how to get information about settings which name contains `min_i`.
+
+``` sql
+SELECT *
+FROM system.settings
+WHERE name LIKE '%min_i%'
+```
+
+``` text
+┌─name────────────────────────────────────────┬─value─────┬─changed─┬─description───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬─min──┬─max──┬─readonly─┐
+│ min_insert_block_size_rows                  │ 1048576   │       0 │ Squash blocks passed to INSERT query to specified size in rows, if blocks are not big enough.                                                                         │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │        0 │
+│ min_insert_block_size_bytes                 │ 268435456 │       0 │ Squash blocks passed to INSERT query to specified size in bytes, if blocks are not big enough.                                                                        │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │        0 │
+│ read_backoff_min_interval_between_events_ms │ 1000      │       0 │ Settings to reduce the number of threads in case of slow reads. Do not pay attention to the event, if the previous one has passed less than a certain amount of time. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │        0 │
+└─────────────────────────────────────────────┴───────────┴─────────┴───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴──────┴──────┴──────────┘
+```
+
+Using of `WHERE changed` can be useful, for example, when you want to check:
+
+-   Whether settings in configuration files are loaded correctly and are in use.
+-   Settings that changed in the current session.
+
+<!-- -->
+
+``` sql
+SELECT * FROM system.settings WHERE changed AND name='load_balancing'
+```
+
+**See also**
+
+-   [Settings](../../operations/settings/index.md#session-settings-intro)
+-   [Permissions for Queries](../../operations/settings/permissions-for-queries.md#settings_readonly)
+-   [Constraints on Settings](../../operations/settings/constraints-on-settings.md)
+-   [SHOW SETTINGS](../../sql-reference/statements/show.md#show-settings) statement
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/settings) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/settings_profile_elements.md b/docs/en/reference/operations/system-tables/settings_profile_elements.md
new file mode 100644
index 00000000000..5a010d6239a
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/settings_profile_elements.md
@@ -0,0 +1,30 @@
+# settings_profile_elements {#system_tables-settings_profile_elements}
+
+Describes the content of the settings profile:
+
+- Сonstraints.
+- Roles and users that the setting applies to.
+- Parent settings profiles.
+
+Columns:
+-    `profile_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Setting profile name.
+
+-    `user_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — User name.
+
+-    `role_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Role name.
+
+-    `index` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Sequential number of the settings profile element.
+
+-    `setting_name` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Setting name.
+
+-    `value` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Setting value.
+
+-    `min` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — The minimum value of the setting. `NULL` if not set.
+
+-    `max` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — The maximum value of the setting. NULL if not set.
+
+-    `readonly` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges))) — Profile that allows only read queries.
+
+-    `inherit_profile` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — A parent profile for this setting profile. `NULL` if not set. Setting profile will inherit all the settings' values and constraints (`min`, `max`, `readonly`) from its parent profiles.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/settings_profile_elements) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/settings_profiles.md b/docs/en/reference/operations/system-tables/settings_profiles.md
new file mode 100644
index 00000000000..ab2020b375d
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/settings_profiles.md
@@ -0,0 +1,24 @@
+# settings_profiles {#system_tables-settings_profiles}
+
+Contains properties of configured setting profiles.
+
+Columns:
+-    `name` ([String](../../sql-reference/data-types/string.md)) — Setting profile name.
+
+-    `id` ([UUID](../../sql-reference/data-types/uuid.md)) — Setting profile ID.
+
+-    `storage` ([String](../../sql-reference/data-types/string.md)) — Path to the storage of setting profiles. Configured in the `access_control_path` parameter.
+
+-    `num_elements` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Number of elements for this profile in the `system.settings_profile_elements` table.
+
+-    `apply_to_all` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows that the settings profile set for all roles and/or users.
+
+-    `apply_to_list` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — List of the roles and/or users to which the setting profile is applied.
+
+-    `apply_to_except` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — The setting profile is applied to all roles and/or users excepting of the listed ones.
+
+## See Also {#see-also}
+
+-   [SHOW PROFILES](../../sql-reference/statements/show.md#show-profiles-statement)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/settings_profiles) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/stack_trace.md b/docs/en/reference/operations/system-tables/stack_trace.md
new file mode 100644
index 00000000000..2aa1c5af125
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/stack_trace.md
@@ -0,0 +1,91 @@
+# stack_trace {#system-tables_stack_trace}
+
+Contains stack traces of all server threads. Allows developers to introspect the server state.
+
+To analyze stack frames, use the `addressToLine`, `addressToLineWithInlines`, `addressToSymbol` and `demangle` [introspection functions](../../sql-reference/functions/introspection.md).
+
+Columns:
+
+-   `thread_name` ([String](../../sql-reference/data-types/string.md)) — Thread name.
+-   `thread_id` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Thread identifier.
+-   `query_id` ([String](../../sql-reference/data-types/string.md)) — Query identifier that can be used to get details about a query that was running from the [query_log](../system-tables/query_log.md) system table.
+-   `trace` ([Array(UInt64)](../../sql-reference/data-types/array.md)) — A [stack trace](https://en.wikipedia.org/wiki/Stack_trace) which represents a list of physical addresses where the called methods are stored.
+
+**Example**
+
+Enabling introspection functions:
+
+``` sql
+SET allow_introspection_functions = 1;
+```
+
+Getting symbols from ClickHouse object files:
+
+``` sql
+WITH arrayMap(x -> demangle(addressToSymbol(x)), trace) AS all SELECT thread_name, thread_id, query_id, arrayStringConcat(all, '\n') AS res FROM system.stack_trace LIMIT 1 \G;
+```
+
+``` text
+Row 1:
+──────
+thread_name: clickhouse-serv
+
+thread_id: 686
+query_id:  1a11f70b-626d-47c1-b948-f9c7b206395d
+res:       sigqueue
+DB::StorageSystemStackTrace::fillData(std::__1::vector<COW<DB::IColumn>::mutable_ptr<DB::IColumn>, std::__1::allocator<COW<DB::IColumn>::mutable_ptr<DB::IColumn> > >&, DB::Context const&, DB::SelectQueryInfo const&) const
+DB::IStorageSystemOneBlock<DB::StorageSystemStackTrace>::read(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&, DB::SelectQueryInfo const&, DB::Context const&, DB::QueryProcessingStage::Enum, unsigned long, unsigned int)
+DB::InterpreterSelectQuery::executeFetchColumns(DB::QueryProcessingStage::Enum, DB::QueryPipeline&, std::__1::shared_ptr<DB::PrewhereInfo> const&, std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&)
+DB::InterpreterSelectQuery::executeImpl(DB::QueryPipeline&, std::__1::shared_ptr<DB::IBlockInputStream> const&, std::__1::optional<DB::Pipe>)
+DB::InterpreterSelectQuery::execute()
+DB::InterpreterSelectWithUnionQuery::execute()
+DB::executeQueryImpl(char const*, char const*, DB::Context&, bool, DB::QueryProcessingStage::Enum, bool, DB::ReadBuffer*)
+DB::executeQuery(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, DB::Context&, bool, DB::QueryProcessingStage::Enum, bool)
+DB::TCPHandler::runImpl()
+DB::TCPHandler::run()
+Poco::Net::TCPServerConnection::start()
+Poco::Net::TCPServerDispatcher::run()
+Poco::PooledThread::run()
+Poco::ThreadImpl::runnableEntry(void*)
+start_thread
+__clone
+```
+
+Getting filenames and line numbers in ClickHouse source code:
+
+``` sql
+WITH arrayMap(x -> addressToLine(x), trace) AS all, arrayFilter(x -> x LIKE '%/dbms/%', all) AS dbms SELECT thread_name, thread_id, query_id, arrayStringConcat(notEmpty(dbms) ? dbms : all, '\n') AS res FROM system.stack_trace LIMIT 1 \G;
+```
+
+``` text
+Row 1:
+──────
+thread_name: clickhouse-serv
+
+thread_id: 686
+query_id:  cad353e7-1c29-4b2e-949f-93e597ab7a54
+res:       /lib/x86_64-linux-gnu/libc-2.27.so
+/build/obj-x86_64-linux-gnu/../src/Storages/System/StorageSystemStackTrace.cpp:182
+/build/obj-x86_64-linux-gnu/../contrib/libcxx/include/vector:656
+/build/obj-x86_64-linux-gnu/../src/Interpreters/InterpreterSelectQuery.cpp:1338
+/build/obj-x86_64-linux-gnu/../src/Interpreters/InterpreterSelectQuery.cpp:751
+/build/obj-x86_64-linux-gnu/../contrib/libcxx/include/optional:224
+/build/obj-x86_64-linux-gnu/../src/Interpreters/InterpreterSelectWithUnionQuery.cpp:192
+/build/obj-x86_64-linux-gnu/../src/Interpreters/executeQuery.cpp:384
+/build/obj-x86_64-linux-gnu/../src/Interpreters/executeQuery.cpp:643
+/build/obj-x86_64-linux-gnu/../src/Server/TCPHandler.cpp:251
+/build/obj-x86_64-linux-gnu/../src/Server/TCPHandler.cpp:1197
+/build/obj-x86_64-linux-gnu/../contrib/poco/Net/src/TCPServerConnection.cpp:57
+/build/obj-x86_64-linux-gnu/../contrib/libcxx/include/atomic:856
+/build/obj-x86_64-linux-gnu/../contrib/poco/Foundation/include/Poco/Mutex_POSIX.h:59
+/build/obj-x86_64-linux-gnu/../contrib/poco/Foundation/include/Poco/AutoPtr.h:223
+/lib/x86_64-linux-gnu/libpthread-2.27.so
+/lib/x86_64-linux-gnu/libc-2.27.so
+```
+
+**See Also**
+
+-   [Introspection Functions](../../sql-reference/functions/introspection.md) — Which introspection functions are available and how to use them.
+-   [system.trace_log](../system-tables/trace_log.md) — Contains stack traces collected by the sampling query profiler.
+-   [arrayMap](../../sql-reference/functions/array-functions.md#array-map) — Description and usage example of the `arrayMap` function.
+-   [arrayFilter](../../sql-reference/functions/array-functions.md#array-filter) — Description and usage example of the `arrayFilter` function.
diff --git a/docs/en/reference/operations/system-tables/storage_policies.md b/docs/en/reference/operations/system-tables/storage_policies.md
new file mode 100644
index 00000000000..adbb2f8434e
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/storage_policies.md
@@ -0,0 +1,17 @@
+# storage_policies {#system_tables-storage_policies}
+
+Contains information about storage policies and volumes defined in the [server configuration](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes_configure).
+
+Columns:
+
+-   `policy_name` ([String](../../sql-reference/data-types/string.md)) — Name of the storage policy.
+-   `volume_name` ([String](../../sql-reference/data-types/string.md)) — Volume name defined in the storage policy.
+-   `volume_priority` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Volume order number in the configuration, the data fills the volumes according this priority, i.e. data during inserts and merges is written to volumes with a lower priority (taking into account other rules: TTL, `max_data_part_size`, `move_factor`).
+-   `disks` ([Array(String)](../../sql-reference/data-types/array.md)) — Disk names, defined in the storage policy.
+-   `max_data_part_size` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Maximum size of a data part that can be stored on volume disks (0 — no limit).
+-   `move_factor` ([Float64](../../sql-reference/data-types/float.md)) — Ratio of free disk space. When the ratio exceeds the value of configuration parameter, ClickHouse start to move data to the next volume in order.
+-   `prefer_not_to_merge` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Value of the `prefer_not_to_merge` setting. When this setting is enabled, merging data on this volume is not allowed. This allows controlling how ClickHouse works with slow disks.
+
+If the storage policy contains more then one volume, then information for each volume is stored in the individual row of the table.
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/storage_policies) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/table_engines.md b/docs/en/reference/operations/system-tables/table_engines.md
new file mode 100644
index 00000000000..d3ac8da1d70
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/table_engines.md
@@ -0,0 +1,38 @@
+# table_engines {#system-table-engines}
+
+Contains description of table engines supported by server and their feature support information.
+
+This table contains the following columns (the column type is shown in brackets):
+
+-   `name` (String) — The name of table engine.
+-   `supports_settings` (UInt8) — Flag that indicates if table engine supports `SETTINGS` clause.
+-   `supports_skipping_indices` (UInt8) — Flag that indicates if table engine supports [skipping indices](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-data_skipping-indexes).
+-   `supports_ttl` (UInt8) — Flag that indicates if table engine supports [TTL](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl).
+-   `supports_sort_order` (UInt8) — Flag that indicates if table engine supports clauses `PARTITION_BY`, `PRIMARY_KEY`, `ORDER_BY` and `SAMPLE_BY`.
+-   `supports_replication` (UInt8) — Flag that indicates if table engine supports [data replication](../../engines/table-engines/mergetree-family/replication.md).
+-   `supports_duduplication` (UInt8) — Flag that indicates if table engine supports data deduplication.
+-   `supports_parallel_insert` (UInt8) — Flag that indicates if table engine supports parallel insert (see [`max_insert_threads`](../../operations/settings/settings.md#settings-max-insert-threads) setting).
+
+Example:
+
+``` sql
+SELECT *
+FROM system.table_engines
+WHERE name in ('Kafka', 'MergeTree', 'ReplicatedCollapsingMergeTree')
+```
+
+``` text
+┌─name──────────────────────────┬─supports_settings─┬─supports_skipping_indices─┬─supports_sort_order─┬─supports_ttl─┬─supports_replication─┬─supports_deduplication─┬─supports_parallel_insert─┐
+│ MergeTree                     │                 1 │                         1 │                   1 │            1 │                    0 │                      0 │                        1 │
+│ Kafka                         │                 1 │                         0 │                   0 │            0 │                    0 │                      0 │                        0 │
+│ ReplicatedCollapsingMergeTree │                 1 │                         1 │                   1 │            1 │                    1 │                      1 │                        1 │
+└───────────────────────────────┴───────────────────┴───────────────────────────┴─────────────────────┴──────────────┴──────────────────────┴────────────────────────┴──────────────────────────┘
+```
+
+**See also**
+
+-   MergeTree family [query clauses](../../engines/table-engines/mergetree-family/mergetree.md#mergetree-query-clauses)
+-   Kafka [settings](../../engines/table-engines/integrations/kafka.md#table_engine-kafka-creating-a-table)
+-   Join [settings](../../engines/table-engines/special/join.md#join-limitations-and-settings)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/table_engines) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/tables.md b/docs/en/reference/operations/system-tables/tables.md
new file mode 100644
index 00000000000..8286d51aed6
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/tables.md
@@ -0,0 +1,125 @@
+# tables {#system-tables}
+
+Contains metadata of each table that the server knows about.
+
+[Detached](../../sql-reference/statements/detach.md) tables are not shown in `system.tables`.
+
+[Temporary tables](../../sql-reference/statements/create/table.md#temporary-tables) are visible in the `system.tables` only in those session where they have been created. They are shown with the empty `database` field and with the `is_temporary` flag switched on.
+
+Columns:
+
+-   `database` ([String](../../sql-reference/data-types/string.md)) — The name of the database the table is in.
+
+-   `name` ([String](../../sql-reference/data-types/string.md)) — Table name.
+
+-   `engine` ([String](../../sql-reference/data-types/string.md)) — Table engine name (without parameters).
+
+-   `is_temporary` ([UInt8](../../sql-reference/data-types/int-uint.md)) - Flag that indicates whether the table is temporary.
+
+-   `data_path` ([String](../../sql-reference/data-types/string.md)) - Path to the table data in the file system.
+
+-   `metadata_path` ([String](../../sql-reference/data-types/string.md)) - Path to the table metadata in the file system.
+
+-   `metadata_modification_time` ([DateTime](../../sql-reference/data-types/datetime.md)) - Time of latest modification of the table metadata.
+
+-   `dependencies_database` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) - Database dependencies.
+
+-   `dependencies_table` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) - Table dependencies ([MaterializedView](../../engines/table-engines/special/materializedview.md) tables based on the current table).
+
+-   `create_table_query` ([String](../../sql-reference/data-types/string.md)) - The query that was used to create the table.
+
+-   `engine_full` ([String](../../sql-reference/data-types/string.md)) - Parameters of the table engine.
+
+-   `as_select` ([String](../../sql-reference/data-types/string.md)) - `SELECT` query for view.
+
+-   `partition_key` ([String](../../sql-reference/data-types/string.md)) - The partition key expression specified in the table.
+
+-   `sorting_key` ([String](../../sql-reference/data-types/string.md)) - The sorting key expression specified in the table.
+
+-   `primary_key` ([String](../../sql-reference/data-types/string.md)) - The primary key expression specified in the table.
+
+-   `sampling_key` ([String](../../sql-reference/data-types/string.md)) - The sampling key expression specified in the table.
+
+-   `storage_policy` ([String](../../sql-reference/data-types/string.md)) - The storage policy:
+
+    -   [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes)
+    -   [Distributed](../../engines/table-engines/special/distributed.md#distributed)
+
+-   `total_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) - Total number of rows, if it is possible to quickly determine exact number of rows in the table, otherwise `NULL` (including underying `Buffer` table).
+
+-   `total_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) - Total number of bytes, if it is possible to quickly determine exact number of bytes for the table on storage, otherwise `NULL` (does not includes any underlying storage).
+
+    -   If the table stores data on disk, returns used space on disk (i.e. compressed).
+    -   If the table stores data in memory, returns approximated number of used bytes in memory.
+
+-   `lifetime_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) - Total number of rows INSERTed since server start (only for `Buffer` tables).
+
+-   `lifetime_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) - Total number of bytes INSERTed since server start (only for `Buffer` tables).
+
+-   `comment` ([String](../../sql-reference/data-types/string.md)) - The comment for the table.
+
+-   `has_own_data` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag that indicates whether the table itself stores some data on disk or only accesses some other source.
+
+The `system.tables` table is used in `SHOW TABLES` query implementation.
+
+**Example**
+
+```sql
+SELECT * FROM system.tables LIMIT 2 FORMAT Vertical;
+```
+
+```text
+Row 1:
+──────
+database:                   base
+name:                       t1
+uuid:                       81b1c20a-b7c6-4116-a2ce-7583fb6b6736
+engine:                     MergeTree
+is_temporary:               0
+data_paths:                 ['/var/lib/clickhouse/store/81b/81b1c20a-b7c6-4116-a2ce-7583fb6b6736/']
+metadata_path:              /var/lib/clickhouse/store/461/461cf698-fd0b-406d-8c01-5d8fd5748a91/t1.sql
+metadata_modification_time: 2021-01-25 19:14:32
+dependencies_database:      []
+dependencies_table:         []
+create_table_query:         CREATE TABLE base.t1 (`n` UInt64) ENGINE = MergeTree ORDER BY n SETTINGS index_granularity = 8192
+engine_full:                MergeTree ORDER BY n SETTINGS index_granularity = 8192
+as_select:                  SELECT database AS table_catalog
+partition_key:
+sorting_key:                n
+primary_key:                n
+sampling_key:
+storage_policy:             default
+total_rows:                 1
+total_bytes:                99
+lifetime_rows:              ᴺᵁᴸᴸ
+lifetime_bytes:             ᴺᵁᴸᴸ
+comment:
+has_own_data:               0
+
+Row 2:
+──────
+database:                   default
+name:                       53r93yleapyears
+uuid:                       00000000-0000-0000-0000-000000000000
+engine:                     MergeTree
+is_temporary:               0
+data_paths:                 ['/var/lib/clickhouse/data/default/53r93yleapyears/']
+metadata_path:              /var/lib/clickhouse/metadata/default/53r93yleapyears.sql
+metadata_modification_time: 2020-09-23 09:05:36
+dependencies_database:      []
+dependencies_table:         []
+create_table_query:         CREATE TABLE default.`53r93yleapyears` (`id` Int8, `febdays` Int8) ENGINE = MergeTree ORDER BY id SETTINGS index_granularity = 8192
+engine_full:                MergeTree ORDER BY id SETTINGS index_granularity = 8192
+as_select:                  SELECT name AS catalog_name
+partition_key:
+sorting_key:                id
+primary_key:                id
+sampling_key:
+storage_policy:             default
+total_rows:                 2
+total_bytes:                155
+lifetime_rows:              ᴺᵁᴸᴸ
+lifetime_bytes:             ᴺᵁᴸᴸ
+comment:
+has_own_data:               0
+```
diff --git a/docs/en/reference/operations/system-tables/text_log.md b/docs/en/reference/operations/system-tables/text_log.md
new file mode 100644
index 00000000000..e4967dc8d0b
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/text_log.md
@@ -0,0 +1,53 @@
+# text_log {#system_tables-text_log}
+
+Contains logging entries. The logging level which goes to this table can be limited to the `text_log.level` server setting.
+
+Columns:
+
+-   `event_date` (Date) — Date of the entry.
+-   `event_time` (DateTime) — Time of the entry.
+-   `event_time_microseconds` (DateTime) — Time of the entry with microseconds precision.
+-   `microseconds` (UInt32) — Microseconds of the entry.
+-   `thread_name` (String) — Name of the thread from which the logging was done.
+-   `thread_id` (UInt64) — OS thread ID.
+-   `level` (`Enum8`) — Entry level. Possible values:
+    -   `1` or `'Fatal'`.
+    -   `2` or `'Critical'`.
+    -   `3` or `'Error'`.
+    -   `4` or `'Warning'`.
+    -   `5` or `'Notice'`.
+    -   `6` or `'Information'`.
+    -   `7` or `'Debug'`.
+    -   `8` or `'Trace'`.
+-   `query_id` (String) — ID of the query.
+-   `logger_name` (LowCardinality(String)) — Name of the logger (i.e. `DDLWorker`).
+-   `message` (String) — The message itself.
+-   `revision` (UInt32) — ClickHouse revision.
+-   `source_file` (LowCardinality(String)) — Source file from which the logging was done.
+-   `source_line` (UInt64) — Source line from which the logging was done.
+
+**Example**
+
+``` sql
+SELECT * FROM system.text_log LIMIT 1 \G
+```
+
+``` text
+Row 1:
+──────
+event_date:              2020-09-10
+event_time:              2020-09-10 11:23:07
+event_time_microseconds: 2020-09-10 11:23:07.871397
+microseconds:            871397
+thread_name:             clickhouse-serv
+thread_id:               564917
+level:                   Information
+query_id:
+logger_name:             DNSCacheUpdater
+message:                 Update period 15 seconds
+revision:                54440
+source_file:             /ClickHouse/src/Interpreters/DNSCacheUpdater.cpp; void DB::DNSCacheUpdater::start()
+source_line:             45
+```
+
+ [Original article](https://clickhouse.com/docs/en/operations/system-tables/text_log) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/time_zones.md b/docs/en/reference/operations/system-tables/time_zones.md
new file mode 100644
index 00000000000..899e115152f
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/time_zones.md
@@ -0,0 +1,30 @@
+# time_zones {#system-time_zones}
+
+Contains a list of time zones that are supported by the ClickHouse server. This list of timezones might vary depending on the version of ClickHouse.
+
+Columns:
+
+-   `time_zone` (String) — List of supported time zones.
+
+**Example**
+
+``` sql
+SELECT * FROM system.time_zones LIMIT 10
+```
+
+``` text
+┌─time_zone──────────┐
+│ Africa/Abidjan     │
+│ Africa/Accra       │
+│ Africa/Addis_Ababa │
+│ Africa/Algiers     │
+│ Africa/Asmara      │
+│ Africa/Asmera      │
+│ Africa/Bamako      │
+│ Africa/Bangui      │
+│ Africa/Banjul      │
+│ Africa/Bissau      │
+└────────────────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/time_zones) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/trace_log.md b/docs/en/reference/operations/system-tables/trace_log.md
new file mode 100644
index 00000000000..ace5662e919
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/trace_log.md
@@ -0,0 +1,57 @@
+# trace_log {#system_tables-trace_log}
+
+Contains stack traces collected by the sampling query profiler.
+
+ClickHouse creates this table when the [trace_log](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-trace_log) server configuration section is set. Also the [query_profiler_real_time_period_ns](../../operations/settings/settings.md#query_profiler_real_time_period_ns) and [query_profiler_cpu_time_period_ns](../../operations/settings/settings.md#query_profiler_cpu_time_period_ns) settings should be set.
+
+To analyze logs, use the `addressToLine`, `addressToLineWithInlines`, `addressToSymbol` and `demangle` introspection functions.
+
+Columns:
+
+-   `event_date` ([Date](../../sql-reference/data-types/date.md)) — Date of sampling moment.
+
+-   `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Timestamp of the sampling moment.
+
+-   `event_time_microseconds` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — Timestamp of the sampling moment with microseconds precision.
+
+-   `timestamp_ns` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Timestamp of the sampling moment in nanoseconds.
+
+-   `revision` ([UInt32](../../sql-reference/data-types/int-uint.md)) — ClickHouse server build revision.
+
+    When connecting to the server by `clickhouse-client`, you see the string similar to `Connected to ClickHouse server version 19.18.1 revision 54429.`. This field contains the `revision`, but not the `version` of a server.
+
+-   `trace_type` ([Enum8](../../sql-reference/data-types/enum.md)) — Trace type:
+
+    -   `Real` represents collecting stack traces by wall-clock time.
+    -   `CPU` represents collecting stack traces by CPU time.
+    -   `Memory` represents collecting allocations and deallocations when memory allocation exceeds the subsequent watermark.
+    -   `MemorySample` represents collecting random allocations and deallocations.
+
+-   `thread_number` ([UInt32](../../sql-reference/data-types/int-uint.md)) — Thread identifier.
+
+-   `query_id` ([String](../../sql-reference/data-types/string.md)) — Query identifier that can be used to get details about a query that was running from the [query_log](#system_tables-query_log) system table.
+
+-   `trace` ([Array(UInt64)](../../sql-reference/data-types/array.md)) — Stack trace at the moment of sampling. Each element is a virtual memory address inside ClickHouse server process.
+
+**Example**
+
+``` sql
+SELECT * FROM system.trace_log LIMIT 1 \G
+```
+
+``` text
+Row 1:
+──────
+event_date:              2020-09-10
+event_time:              2020-09-10 11:23:09
+event_time_microseconds: 2020-09-10 11:23:09.872924
+timestamp_ns:            1599762189872924510
+revision:                54440
+trace_type:              Memory
+thread_id:               564963
+query_id:
+trace:                   [371912858,371912789,371798468,371799717,371801313,371790250,624462773,566365041,566440261,566445834,566460071,566459914,566459842,566459580,566459469,566459389,566459341,566455774,371993941,371988245,372158848,372187428,372187309,372187093,372185478,140222123165193,140222122205443]
+size:                    5244400
+```
+
+ [Original article](https://clickhouse.com/docs/en/operations/system-tables/trace_log) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/users.md b/docs/en/reference/operations/system-tables/users.md
new file mode 100644
index 00000000000..95691f4497c
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/users.md
@@ -0,0 +1,34 @@
+# users {#system_tables-users}
+
+Contains a list of [user accounts](../../operations/access-rights.md#user-account-management) configured at the server.
+
+Columns:
+-    `name` ([String](../../sql-reference/data-types/string.md)) — User name.
+
+-    `id` ([UUID](../../sql-reference/data-types/uuid.md)) — User ID.
+
+-    `storage` ([String](../../sql-reference/data-types/string.md)) — Path to the storage of users. Configured in the `access_control_path` parameter.
+
+-    `auth_type` ([Enum8](../../sql-reference/data-types/enum.md)('no_password' = 0,'plaintext_password' = 1, 'sha256_password' = 2, 'double_sha1_password' = 3)) — Shows the authentication type. There are multiple ways of user identification: with no password, with plain text password, with [SHA256](https://ru.wikipedia.org/wiki/SHA-2)-encoded password or with [double SHA-1](https://ru.wikipedia.org/wiki/SHA-1)-encoded password.
+
+-    `auth_params` ([String](../../sql-reference/data-types/string.md)) — Authentication parameters in the JSON format depending on the `auth_type`.
+
+-    `host_ip` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — IP addresses of hosts that are allowed to connect to the ClickHouse server.
+
+-    `host_names` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Names of hosts that are allowed to connect to the ClickHouse server.
+
+-    `host_names_regexp` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Regular expression for host names that are allowed to connect to the ClickHouse server.
+
+-    `host_names_like` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — Names of hosts that are allowed to connect to the ClickHouse server, set using the LIKE predicate.
+
+-    `default_roles_all` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows that all granted roles set for user by default.
+
+-    `default_roles_list` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — List of granted roles provided by default.
+
+-    `default_roles_except` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) — All the granted roles set as default excepting of the listed ones.
+
+## See Also {#see-also}
+
+-   [SHOW USERS](../../sql-reference/statements/show.md#show-users-statement)
+
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/users) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/zookeeper.md b/docs/en/reference/operations/system-tables/zookeeper.md
new file mode 100644
index 00000000000..e8232483f6f
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/zookeeper.md
@@ -0,0 +1,75 @@
+# zookeeper {#system-zookeeper}
+
+The table does not exist if ZooKeeper is not configured. Allows reading data from the ZooKeeper cluster defined in the config.
+The query must either have a ‘path =’   condition or a `path IN`  condition set with the `WHERE` clause as shown below. This corresponds to the path of the children in ZooKeeper that you want to get data for.
+
+The query `SELECT * FROM system.zookeeper WHERE path = '/clickhouse'` outputs data for all children on the `/clickhouse` node.
+To output data for all root nodes, write path = ‘/’.
+If the path specified in ‘path’ does not exist, an exception will be thrown.
+
+The query `SELECT * FROM system.zookeeper WHERE path IN ('/', '/clickhouse')` outputs data for all children on the `/` and `/clickhouse` node.
+If in the specified ‘path’ collection has does not exist path, an exception will be thrown.
+It can be used to do a batch of ZooKeeper path queries.
+
+Columns:
+
+-   `name` (String) — The name of the node.
+-   `path` (String) — The path to the node.
+-   `value` (String) — Node value.
+-   `dataLength` (Int32) — Size of the value.
+-   `numChildren` (Int32) — Number of descendants.
+-   `czxid` (Int64) — ID of the transaction that created the node.
+-   `mzxid` (Int64) — ID of the transaction that last changed the node.
+-   `pzxid` (Int64) — ID of the transaction that last deleted or added descendants.
+-   `ctime` (DateTime) — Time of node creation.
+-   `mtime` (DateTime) — Time of the last modification of the node.
+-   `version` (Int32) — Node version: the number of times the node was changed.
+-   `cversion` (Int32) — Number of added or removed descendants.
+-   `aversion` (Int32) — Number of changes to the ACL.
+-   `ephemeralOwner` (Int64) — For ephemeral nodes, the ID of the session that owns this node.
+
+Example:
+
+``` sql
+SELECT *
+FROM system.zookeeper
+WHERE path = '/clickhouse/tables/01-08/visits/replicas'
+FORMAT Vertical
+```
+
+``` text
+Row 1:
+──────
+name:           example01-08-1
+value:
+czxid:          932998691229
+mzxid:          932998691229
+ctime:          2015-03-27 16:49:51
+mtime:          2015-03-27 16:49:51
+version:        0
+cversion:       47
+aversion:       0
+ephemeralOwner: 0
+dataLength:     0
+numChildren:    7
+pzxid:          987021031383
+path:           /clickhouse/tables/01-08/visits/replicas
+
+Row 2:
+──────
+name:           example01-08-2
+value:
+czxid:          933002738135
+mzxid:          933002738135
+ctime:          2015-03-27 16:57:01
+mtime:          2015-03-27 16:57:01
+version:        0
+cversion:       37
+aversion:       0
+ephemeralOwner: 0
+dataLength:     0
+numChildren:    7
+pzxid:          987021252247
+path:           /clickhouse/tables/01-08/visits/replicas
+```
+[Original article](https://clickhouse.com/docs/en/operations/system-tables/zookeeper) <!--hide-->
diff --git a/docs/en/reference/operations/system-tables/zookeeper_log.md b/docs/en/reference/operations/system-tables/zookeeper_log.md
new file mode 100644
index 00000000000..919c4245d5d
--- /dev/null
+++ b/docs/en/reference/operations/system-tables/zookeeper_log.md
@@ -0,0 +1,129 @@
+# zookeeper_log {#system-zookeeper_log}
+
+This table contains information about the parameters of the request to the ZooKeeper server and the response from it.
+
+For requests, only columns with request parameters are filled in, and the remaining columns are filled with default values (`0` or `NULL`). When the response arrives, the data from the response is added to the other columns.
+
+Columns with request parameters:
+
+-   `type` ([Enum](../../sql-reference/data-types/enum.md)) — Event type in the ZooKeeper client. Can have one of the following values:
+    -   `Request` — The request has been sent.
+    -   `Response` — The response was received.
+    -   `Finalize` — The connection is lost, no response was received.
+-   `event_date` ([Date](../../sql-reference/data-types/date.md)) — The date when the event happened.
+-   `event_time` ([DateTime64](../../sql-reference/data-types/datetime64.md)) — The date and time when the event happened.
+-   `address` ([IPv6](../../sql-reference/data-types/domains/ipv6.md)) — IP address of ZooKeeper server that was used to make the request.
+-   `port` ([UInt16](../../sql-reference/data-types/int-uint.md)) — The port of ZooKeeper server that was used to make the request.
+-   `session_id` ([Int64](../../sql-reference/data-types/int-uint.md)) — The session ID that the ZooKeeper server sets for each connection.
+-   `xid` ([Int32](../../sql-reference/data-types/int-uint.md)) — The ID of the request within the session. This is usually a sequential request number. It is the same for the request row and the paired `response`/`finalize` row.
+-   `has_watch` ([UInt8](../../sql-reference/data-types/int-uint.md)) — The request whether the [watch](https://zookeeper.apache.org/doc/r3.3.3/zookeeperProgrammers.html#ch_zkWatches) has been set.
+-   `op_num` ([Enum](../../sql-reference/data-types/enum.md)) — The type of request or response.
+-   `path` ([String](../../sql-reference/data-types/string.md)) — The path to the ZooKeeper node specified in the request, or an empty string  if the request not requires specifying a path.
+-   `data` ([String](../../sql-reference/data-types/string.md)) — The data written to the ZooKeeper node (for the `SET` and `CREATE` requests — what the request wanted to write, for the response to the `GET` request — what was read) or an empty string.
+-   `is_ephemeral` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Is the ZooKeeper node being created as an [ephemeral](https://zookeeper.apache.org/doc/r3.3.3/zookeeperProgrammers.html#Ephemeral+Nodes).
+-   `is_sequential` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Is the ZooKeeper node being created as an [sequential](https://zookeeper.apache.org/doc/r3.3.3/zookeeperProgrammers.html#Sequence+Nodes+--+Unique+Naming).
+-   `version` ([Nullable(Int32)](../../sql-reference/data-types/nullable.md)) — The version of the ZooKeeper node that the request expects when executing. This is supported for `CHECK`, `SET`, `REMOVE` requests (is relevant `-1` if the request does not check the version or `NULL` for other requests that do not support version checking).
+-   `requests_size` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The number of requests included in the multi request (this is a special request that consists of several consecutive ordinary requests and executes them atomically). All requests included in multi request will have the same `xid`.
+-   `request_idx` ([UInt32](../../sql-reference/data-types/int-uint.md)) — The number of the request included in multi request (for multi request — `0`, then in order from `1`).
+
+Columns with request response parameters:
+
+-   `zxid` ([Int64](../../sql-reference/data-types/int-uint.md)) — ZooKeeper transaction ID. The serial number issued by the ZooKeeper server in response to a successfully executed request (`0` if the request was not executed/returned an error/the client does not know whether the request was executed).
+-   `error` ([Nullable(Enum)](../../sql-reference/data-types/nullable.md)) — Error code. Can have many values, here are just some of them:
+    -   `ZOK` — The request was executed seccessfully.
+    -   `ZCONNECTIONLOSS` — The connection was lost.
+    -   `ZOPERATIONTIMEOUT` — The request execution timeout has expired.
+	-   `ZSESSIONEXPIRED` — The session has expired.
+    -   `NULL` — The request is completed.
+-   `watch_type` ([Nullable(Enum)](../../sql-reference/data-types/nullable.md)) — The type of the `watch` event (for responses with `op_num` = `Watch`), for the remaining responses: `NULL`.
+-   `watch_state` ([Nullable(Enum)](../../sql-reference/data-types/nullable.md)) — The status of the `watch` event (for responses with `op_num` = `Watch`), for the remaining responses: `NULL`.
+-   `path_created` ([String](../../sql-reference/data-types/string.md)) — The path to the created ZooKeeper node (for responses to the `CREATE` request), may differ from the `path` if the node is created as a `sequential`.
+-   `stat_czxid` ([Int64](../../sql-reference/data-types/int-uint.md)) — The `zxid` of the change that caused this ZooKeeper node to be created.
+-   `stat_mzxid` ([Int64](../../sql-reference/data-types/int-uint.md)) — The `zxid` of the change that last modified this ZooKeeper node.
+-   `stat_pzxid` ([Int64](../../sql-reference/data-types/int-uint.md)) — The transaction ID of the change that last modified childern of this ZooKeeper node.
+-   `stat_version` ([Int32](../../sql-reference/data-types/int-uint.md)) — The number of changes to the data of this ZooKeeper node.
+-   `stat_cversion` ([Int32](../../sql-reference/data-types/int-uint.md)) — The number of changes to the children of this ZooKeeper node.
+-   `stat_dataLength` ([Int32](../../sql-reference/data-types/int-uint.md)) — The length of the data field of this ZooKeeper node.
+-   `stat_numChildren` ([Int32](../../sql-reference/data-types/int-uint.md)) — The number of children of this ZooKeeper node.
+-   `children` ([Array(String)](../../sql-reference/data-types/array.md)) — The list of child ZooKeeper nodes (for responses to `LIST` request).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT * FROM system.zookeeper_log WHERE (session_id = '106662742089334927') AND (xid = '10858') FORMAT Vertical;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+type:             Request
+event_date:       2021-08-09
+event_time:       2021-08-09 21:38:30.291792
+address:          ::
+port:             2181
+session_id:       106662742089334927
+xid:              10858
+has_watch:        1
+op_num:           List
+path:             /clickhouse/task_queue/ddl
+data:             
+is_ephemeral:     0
+is_sequential:    0
+version:          ᴺᵁᴸᴸ
+requests_size:    0
+request_idx:      0
+zxid:             0
+error:            ᴺᵁᴸᴸ
+watch_type:       ᴺᵁᴸᴸ
+watch_state:      ᴺᵁᴸᴸ
+path_created:     
+stat_czxid:       0
+stat_mzxid:       0
+stat_pzxid:       0
+stat_version:     0
+stat_cversion:    0
+stat_dataLength:  0
+stat_numChildren: 0
+children:         []
+
+Row 2:
+──────
+type:             Response
+event_date:       2021-08-09
+event_time:       2021-08-09 21:38:30.292086
+address:          ::
+port:             2181
+session_id:       106662742089334927
+xid:              10858
+has_watch:        1
+op_num:           List
+path:             /clickhouse/task_queue/ddl
+data:             
+is_ephemeral:     0
+is_sequential:    0
+version:          ᴺᵁᴸᴸ
+requests_size:    0
+request_idx:      0
+zxid:             16926267
+error:            ZOK
+watch_type:       ᴺᵁᴸᴸ
+watch_state:      ᴺᵁᴸᴸ
+path_created:     
+stat_czxid:       16925469
+stat_mzxid:       16925469
+stat_pzxid:       16926179
+stat_version:     0
+stat_cversion:    7
+stat_dataLength:  0
+stat_numChildren: 7
+children:         ['query-0000000006','query-0000000005','query-0000000004','query-0000000003','query-0000000002','query-0000000001','query-0000000000']
+```
+
+**See Also**
+
+-   [ZooKeeper](../../operations/tips.md#zookeeper)
+-   [ZooKeeper guide](https://zookeeper.apache.org/doc/r3.3.3/zookeeperProgrammers.html)
diff --git a/docs/en/reference/operations/tips.md b/docs/en/reference/operations/tips.md
new file mode 100644
index 00000000000..c727c636579
--- /dev/null
+++ b/docs/en/reference/operations/tips.md
@@ -0,0 +1,279 @@
+---
+sidebar_position: 58
+sidebar_label: Usage Recommendations
+---
+
+# Usage Recommendations {#usage-recommendations}
+
+## CPU Scaling Governor {#cpu-scaling-governor}
+
+Always use the `performance` scaling governor. The `on-demand` scaling governor works much worse with constantly high demand.
+
+``` bash
+$ echo 'performance' | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
+```
+
+## CPU Limitations {#cpu-limitations}
+
+Processors can overheat. Use `dmesg` to see if the CPU’s clock rate was limited due to overheating.
+The restriction can also be set externally at the datacenter level. You can use `turbostat` to monitor it under a load.
+
+## RAM {#ram}
+
+For small amounts of data (up to ~200 GB compressed), it is best to use as much memory as the volume of data.
+For large amounts of data and when processing interactive (online) queries, you should use a reasonable amount of RAM (128 GB or more) so the hot data subset will fit in the cache of pages.
+Even for data volumes of ~50 TB per server, using 128 GB of RAM significantly improves query performance compared to 64 GB.
+
+Do not disable overcommit. The value `cat /proc/sys/vm/overcommit_memory` should be 0 or 1. Run
+
+``` bash
+$ echo 0 | sudo tee /proc/sys/vm/overcommit_memory
+```
+
+Use `perf top` to watch the time spent in the kernel for memory management.
+Permanent huge pages also do not need to be allocated.
+
+:::warning    
+If your system has less than 16 GB of RAM, you may experience various memory exceptions because default settings do not match this amount of memory. The recommended amount of RAM is 32 GB or more. You can use ClickHouse in a system with a small amount of RAM, even with 2 GB of RAM, but it requires additional tuning and can ingest at a low rate.
+:::
+
+## Storage Subsystem {#storage-subsystem}
+
+If your budget allows you to use SSD, use SSD.
+If not, use HDD. SATA HDDs 7200 RPM will do.
+
+Give preference to a lot of servers with local hard drives over a smaller number of servers with attached disk shelves.
+But for storing archives with rare queries, shelves will work.
+
+## RAID {#raid}
+
+When using HDD, you can combine their RAID-10, RAID-5, RAID-6 or RAID-50.
+For Linux, software RAID is better (with `mdadm`). We do not recommend using LVM.
+When creating RAID-10, select the `far` layout.
+If your budget allows, choose RAID-10.
+
+If you have more than 4 disks, use RAID-6 (preferred) or RAID-50, instead of RAID-5.
+When using RAID-5, RAID-6 or RAID-50, always increase stripe_cache_size, since the default value is usually not the best choice.
+
+``` bash
+$ echo 4096 | sudo tee /sys/block/md2/md/stripe_cache_size
+```
+
+Calculate the exact number from the number of devices and the block size, using the formula: `2 * num_devices * chunk_size_in_bytes / 4096`.
+
+A block size of 64 KB is sufficient for most RAID configurations. The average clickhouse-server write size is approximately 1 MB (1024 KB), and thus the recommended stripe size is also 1 MB. The block size can be optimized if needed when set to 1 MB divided by the number of non-parity disks in the RAID array, such that each write is parallelized across all available non-parity disks.
+Never set the block size too small or too large.
+
+You can use RAID-0 on SSD.
+Regardless of RAID use, always use replication for data security.
+
+Enable NCQ with a long queue. For HDD, choose the CFQ scheduler, and for SSD, choose noop. Don’t reduce the ‘readahead’ setting.
+For HDD, enable the write cache.
+
+Make sure that [fstrim](https://en.wikipedia.org/wiki/Trim_(computing)) is enabled for NVME and SSD disks in your OS (usually it's implemented using a cronjob or systemd service).
+
+## File System {#file-system}
+
+Ext4 is the most reliable option. Set the mount options `noatime`.
+XFS should be avoided. It works mostly fine but there are some reports about lower performance.
+Most other file systems should also work fine.
+
+Do not use compressed filesystems, because ClickHouse does compression on its own and better.
+It's not recommended to use encrypted filesystems, because you can use builtin encryption in ClickHouse, which is better.
+
+## Linux Kernel {#linux-kernel}
+
+Don’t use an outdated Linux kernel.
+
+## Network {#network}
+
+If you are using IPv6, increase the size of the route cache.
+The Linux kernel prior to 3.2 had a multitude of problems with IPv6 implementation.
+
+Use at least a 10 GB network, if possible. 1 Gb will also work, but it will be much worse for patching replicas with tens of terabytes of data, or for processing distributed queries with a large amount of intermediate data.
+
+## Huge Pages {#huge-pages}
+
+If you are using old Linux kernel, disable transparent huge pages. It interferes with memory allocators, which leads to significant performance degradation.
+On newer Linux kernels transparent huge pages are alright.
+
+``` bash
+$ echo 'madvise' | sudo tee /sys/kernel/mm/transparent_hugepage/enabled
+```
+
+## Hypervisor configuration
+
+If you are using OpenStack, set
+```
+cpu_mode=host-passthrough
+```
+in nova.conf.
+
+If you are using libvirt, set
+```
+<cpu mode='host-passthrough'/>
+```
+in XML configuration.
+
+This is important for ClickHouse to be able to get correct information with `cpuid` instruction.
+Otherwise you may get `Illegal instruction` crashes when hypervisor is run on old CPU models.
+
+## ZooKeeper {#zookeeper}
+
+You are probably already using ZooKeeper for other purposes. You can use the same installation of ZooKeeper, if it isn’t already overloaded.
+
+It’s best to use a fresh version of ZooKeeper – 3.4.9 or later. The version in stable Linux distributions may be outdated.
+
+You should never use manually written scripts to transfer data between different ZooKeeper clusters, because the result will be incorrect for sequential nodes. Never use the “zkcopy” utility for the same reason: https://github.com/ksprojects/zkcopy/issues/15
+
+If you want to divide an existing ZooKeeper cluster into two, the correct way is to increase the number of its replicas and then reconfigure it as two independent clusters.
+
+Do not run ZooKeeper on the same servers as ClickHouse. Because ZooKeeper is very sensitive for latency and ClickHouse may utilize all available system resources.
+
+You can have ZooKeeper observers in an ensemble but ClickHouse servers should not interact with observers.
+
+Do not change `minSessionTimeout` setting, large values may affect ClickHouse restart stability.
+
+With the default settings, ZooKeeper is a time bomb:
+
+> The ZooKeeper server won’t delete files from old snapshots and logs when using the default configuration (see autopurge), and this is the responsibility of the operator.
+
+This bomb must be defused.
+
+The ZooKeeper (3.5.1) configuration below is used in a large production environment:
+
+zoo.cfg:
+
+``` bash
+# http://hadoop.apache.org/zookeeper/docs/current/zookeeperAdmin.html
+
+# The number of milliseconds of each tick
+tickTime=2000
+# The number of ticks that the initial
+# synchronization phase can take
+# This value is not quite motivated
+initLimit=300
+# The number of ticks that can pass between
+# sending a request and getting an acknowledgement
+syncLimit=10
+
+maxClientCnxns=2000
+
+# It is the maximum value that client may request and the server will accept.
+# It is Ok to have high maxSessionTimeout on server to allow clients to work with high session timeout if they want.
+# But we request session timeout of 30 seconds by default (you can change it with session_timeout_ms in ClickHouse config).
+maxSessionTimeout=60000000
+# the directory where the snapshot is stored.
+dataDir=/opt/zookeeper/{{ '{{' }} cluster['name'] {{ '}}' }}/data
+# Place the dataLogDir to a separate physical disc for better performance
+dataLogDir=/opt/zookeeper/{{ '{{' }} cluster['name'] {{ '}}' }}/logs
+
+autopurge.snapRetainCount=10
+autopurge.purgeInterval=1
+
+
+# To avoid seeks ZooKeeper allocates space in the transaction log file in
+# blocks of preAllocSize kilobytes. The default block size is 64M. One reason
+# for changing the size of the blocks is to reduce the block size if snapshots
+# are taken more often. (Also, see snapCount).
+preAllocSize=131072
+
+# Clients can submit requests faster than ZooKeeper can process them,
+# especially if there are a lot of clients. To prevent ZooKeeper from running
+# out of memory due to queued requests, ZooKeeper will throttle clients so that
+# there is no more than globalOutstandingLimit outstanding requests in the
+# system. The default limit is 1,000.ZooKeeper logs transactions to a
+# transaction log. After snapCount transactions are written to a log file a
+# snapshot is started and a new transaction log file is started. The default
+# snapCount is 10,000.
+snapCount=3000000
+
+# If this option is defined, requests will be will logged to a trace file named
+# traceFile.year.month.day.
+#traceFile=
+
+# Leader accepts client connections. Default value is "yes". The leader machine
+# coordinates updates. For higher update throughput at thes slight expense of
+# read throughput the leader can be configured to not accept clients and focus
+# on coordination.
+leaderServes=yes
+
+standaloneEnabled=false
+dynamicConfigFile=/etc/zookeeper-{{ '{{' }} cluster['name'] {{ '}}' }}/conf/zoo.cfg.dynamic
+```
+
+Java version:
+
+``` text
+openjdk 11.0.5-shenandoah 2019-10-15
+OpenJDK Runtime Environment (build 11.0.5-shenandoah+10-adhoc.heretic.src)
+OpenJDK 64-Bit Server VM (build 11.0.5-shenandoah+10-adhoc.heretic.src, mixed mode)
+```
+
+JVM parameters:
+
+``` bash
+NAME=zookeeper-{{ '{{' }} cluster['name'] {{ '}}' }}
+ZOOCFGDIR=/etc/$NAME/conf
+
+# TODO this is really ugly
+# How to find out, which jars are needed?
+# seems, that log4j requires the log4j.properties file to be in the classpath
+CLASSPATH="$ZOOCFGDIR:/usr/build/classes:/usr/build/lib/*.jar:/usr/share/zookeeper-3.6.2/lib/audience-annotations-0.5.0.jar:/usr/share/zookeeper-3.6.2/lib/commons-cli-1.2.jar:/usr/share/zookeeper-3.6.2/lib/commons-lang-2.6.jar:/usr/share/zookeeper-3.6.2/lib/jackson-annotations-2.10.3.jar:/usr/share/zookeeper-3.6.2/lib/jackson-core-2.10.3.jar:/usr/share/zookeeper-3.6.2/lib/jackson-databind-2.10.3.jar:/usr/share/zookeeper-3.6.2/lib/javax.servlet-api-3.1.0.jar:/usr/share/zookeeper-3.6.2/lib/jetty-http-9.4.24.v20191120.jar:/usr/share/zookeeper-3.6.2/lib/jetty-io-9.4.24.v20191120.jar:/usr/share/zookeeper-3.6.2/lib/jetty-security-9.4.24.v20191120.jar:/usr/share/zookeeper-3.6.2/lib/jetty-server-9.4.24.v20191120.jar:/usr/share/zookeeper-3.6.2/lib/jetty-servlet-9.4.24.v20191120.jar:/usr/share/zookeeper-3.6.2/lib/jetty-util-9.4.24.v20191120.jar:/usr/share/zookeeper-3.6.2/lib/jline-2.14.6.jar:/usr/share/zookeeper-3.6.2/lib/json-simple-1.1.1.jar:/usr/share/zookeeper-3.6.2/lib/log4j-1.2.17.jar:/usr/share/zookeeper-3.6.2/lib/metrics-core-3.2.5.jar:/usr/share/zookeeper-3.6.2/lib/netty-buffer-4.1.50.Final.jar:/usr/share/zookeeper-3.6.2/lib/netty-codec-4.1.50.Final.jar:/usr/share/zookeeper-3.6.2/lib/netty-common-4.1.50.Final.jar:/usr/share/zookeeper-3.6.2/lib/netty-handler-4.1.50.Final.jar:/usr/share/zookeeper-3.6.2/lib/netty-resolver-4.1.50.Final.jar:/usr/share/zookeeper-3.6.2/lib/netty-transport-4.1.50.Final.jar:/usr/share/zookeeper-3.6.2/lib/netty-transport-native-epoll-4.1.50.Final.jar:/usr/share/zookeeper-3.6.2/lib/netty-transport-native-unix-common-4.1.50.Final.jar:/usr/share/zookeeper-3.6.2/lib/simpleclient-0.6.0.jar:/usr/share/zookeeper-3.6.2/lib/simpleclient_common-0.6.0.jar:/usr/share/zookeeper-3.6.2/lib/simpleclient_hotspot-0.6.0.jar:/usr/share/zookeeper-3.6.2/lib/simpleclient_servlet-0.6.0.jar:/usr/share/zookeeper-3.6.2/lib/slf4j-api-1.7.25.jar:/usr/share/zookeeper-3.6.2/lib/slf4j-log4j12-1.7.25.jar:/usr/share/zookeeper-3.6.2/lib/snappy-java-1.1.7.jar:/usr/share/zookeeper-3.6.2/lib/zookeeper-3.6.2.jar:/usr/share/zookeeper-3.6.2/lib/zookeeper-jute-3.6.2.jar:/usr/share/zookeeper-3.6.2/lib/zookeeper-prometheus-metrics-3.6.2.jar:/usr/share/zookeeper-3.6.2/etc"
+
+ZOOCFG="$ZOOCFGDIR/zoo.cfg"
+ZOO_LOG_DIR=/var/log/$NAME
+USER=zookeeper
+GROUP=zookeeper
+PIDDIR=/var/run/$NAME
+PIDFILE=$PIDDIR/$NAME.pid
+SCRIPTNAME=/etc/init.d/$NAME
+JAVA=/usr/local/jdk-11/bin/java
+ZOOMAIN="org.apache.zookeeper.server.quorum.QuorumPeerMain"
+ZOO_LOG4J_PROP="INFO,ROLLINGFILE"
+JMXLOCALONLY=false
+JAVA_OPTS="-Xms{{ '{{' }} cluster.get('xms','128M') {{ '}}' }} \
+    -Xmx{{ '{{' }} cluster.get('xmx','1G') {{ '}}' }} \
+    -Xlog:safepoint,gc*=info,age*=debug:file=/var/log/$NAME/zookeeper-gc.log:time,level,tags:filecount=16,filesize=16M
+    -verbose:gc \
+    -XX:+UseG1GC \
+    -Djute.maxbuffer=8388608 \
+    -XX:MaxGCPauseMillis=50"
+```
+
+Salt init:
+
+``` text
+description "zookeeper-{{ '{{' }} cluster['name'] {{ '}}' }} centralized coordination service"
+
+start on runlevel [2345]
+stop on runlevel [!2345]
+
+respawn
+
+limit nofile 8192 8192
+
+pre-start script
+    [ -r "/etc/zookeeper-{{ '{{' }} cluster['name'] {{ '}}' }}/conf/environment" ] || exit 0
+    . /etc/zookeeper-{{ '{{' }} cluster['name'] {{ '}}' }}/conf/environment
+    [ -d $ZOO_LOG_DIR ] || mkdir -p $ZOO_LOG_DIR
+    chown $USER:$GROUP $ZOO_LOG_DIR
+end script
+
+script
+    . /etc/zookeeper-{{ '{{' }} cluster['name'] {{ '}}' }}/conf/environment
+    [ -r /etc/default/zookeeper ] && . /etc/default/zookeeper
+    if [ -z "$JMXDISABLE" ]; then
+        JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=$JMXLOCALONLY"
+    fi
+    exec start-stop-daemon --start -c $USER --exec $JAVA --name zookeeper-{{ '{{' }} cluster['name'] {{ '}}' }} \
+        -- -cp $CLASSPATH $JAVA_OPTS -Dzookeeper.log.dir=${ZOO_LOG_DIR} \
+        -Dzookeeper.root.logger=${ZOO_LOG4J_PROP} $ZOOMAIN $ZOOCFG
+end script
+```
+
+## Antivirus software {#antivirus-software}
+
+If you use antivirus software configure it to skip folders with Clickhouse datafiles (`/var/lib/clickhouse`) otherwise performance may be reduced and you may experience unexpected errors during data ingestion and background merges.
+
+[Original article](https://clickhouse.com/docs/en/operations/tips/)
diff --git a/docs/en/reference/operations/troubleshooting.md b/docs/en/reference/operations/troubleshooting.md
new file mode 100644
index 00000000000..b67282c8aa1
--- /dev/null
+++ b/docs/en/reference/operations/troubleshooting.md
@@ -0,0 +1,144 @@
+---
+sidebar_position: 46
+sidebar_label: Troubleshooting
+---
+
+# Troubleshooting 
+
+-   [Installation](#troubleshooting-installation-errors)
+-   [Connecting to the server](#troubleshooting-accepts-no-connections)
+-   [Query processing](#troubleshooting-does-not-process-queries)
+-   [Efficiency of query processing](#troubleshooting-too-slow)
+
+## Installation {#troubleshooting-installation-errors}
+
+### You Cannot Get Deb Packages from ClickHouse Repository with Apt-get {#you-cannot-get-deb-packages-from-clickhouse-repository-with-apt-get}
+
+-   Check firewall settings.
+-   If you cannot access the repository for any reason, download packages as described in the [install guide](../install.md) article and install them manually using the `sudo dpkg -i <packages>` command. You will also need the `tzdata` package.
+
+## Connecting to the Server {#troubleshooting-accepts-no-connections}
+
+Possible issues:
+
+-   The server is not running.
+-   Unexpected or wrong configuration parameters.
+
+### Server Is Not Running {#server-is-not-running}
+
+**Check if server is runnnig**
+
+Command:
+
+``` bash
+$ sudo service clickhouse-server status
+```
+
+If the server is not running, start it with the command:
+
+``` bash
+$ sudo service clickhouse-server start
+```
+
+**Check logs**
+
+The main log of `clickhouse-server` is in `/var/log/clickhouse-server/clickhouse-server.log` by default.
+
+If the server started successfully, you should see the strings:
+
+-   `<Information> Application: starting up.` — Server started.
+-   `<Information> Application: Ready for connections.` — Server is running and ready for connections.
+
+If `clickhouse-server` start failed with a configuration error, you should see the `<Error>` string with an error description. For example:
+
+``` text
+2019.01.11 15:23:25.549505 [ 45 ] {} <Error> ExternalDictionaries: Failed reloading 'event2id' external dictionary: Poco::Exception. Code: 1000, e.code() = 111, e.displayText() = Connection refused, e.what() = Connection refused
+```
+
+If you do not see an error at the end of the file, look through the entire file starting from the string:
+
+``` text
+<Information> Application: starting up.
+```
+
+If you try to start a second instance of `clickhouse-server` on the server, you see the following log:
+
+``` text
+2019.01.11 15:25:11.151730 [ 1 ] {} <Information> : Starting ClickHouse 19.1.0 with revision 54413
+2019.01.11 15:25:11.154578 [ 1 ] {} <Information> Application: starting up
+2019.01.11 15:25:11.156361 [ 1 ] {} <Information> StatusFile: Status file ./status already exists - unclean restart. Contents:
+PID: 8510
+Started at: 2019-01-11 15:24:23
+Revision: 54413
+
+2019.01.11 15:25:11.156673 [ 1 ] {} <Error> Application: DB::Exception: Cannot lock file ./status. Another server instance in same directory is already running.
+2019.01.11 15:25:11.156682 [ 1 ] {} <Information> Application: shutting down
+2019.01.11 15:25:11.156686 [ 1 ] {} <Debug> Application: Uninitializing subsystem: Logging Subsystem
+2019.01.11 15:25:11.156716 [ 2 ] {} <Information> BaseDaemon: Stop SignalListener thread
+```
+
+**See system.d logs**
+
+If you do not find any useful information in `clickhouse-server` logs or there aren’t any logs, you can view `system.d` logs using the command:
+
+``` bash
+$ sudo journalctl -u clickhouse-server
+```
+
+**Start clickhouse-server in interactive mode**
+
+``` bash
+$ sudo -u clickhouse /usr/bin/clickhouse-server --config-file /etc/clickhouse-server/config.xml
+```
+
+This command starts the server as an interactive app with standard parameters of the autostart script. In this mode `clickhouse-server` prints all the event messages in the console.
+
+### Configuration Parameters {#configuration-parameters}
+
+Check:
+
+-   Docker settings.
+
+    If you run ClickHouse in Docker in an IPv6 network, make sure that `network=host` is set.
+
+-   Endpoint settings.
+
+    Check [listen_host](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-listen_host) and [tcp_port](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-tcp_port) settings.
+
+    ClickHouse server accepts localhost connections only by default.
+
+-   HTTP protocol settings.
+
+    Check protocol settings for the HTTP API.
+
+-   Secure connection settings.
+
+    Check:
+
+    -   The [tcp_port_secure](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-tcp_port_secure) setting.
+    -   Settings for [SSL certificates](../operations/server-configuration-parameters/settings.md#server_configuration_parameters-openssl).
+
+    Use proper parameters while connecting. For example, use the `port_secure` parameter with `clickhouse_client`.
+
+-   User settings.
+
+    You might be using the wrong user name or password.
+
+## Query Processing {#troubleshooting-does-not-process-queries}
+
+If ClickHouse is not able to process the query, it sends an error description to the client. In the `clickhouse-client` you get a description of the error in the console. If you are using the HTTP interface, ClickHouse sends the error description in the response body. For example:
+
+``` bash
+$ curl 'http://localhost:8123/' --data-binary "SELECT a"
+Code: 47, e.displayText() = DB::Exception: Unknown identifier: a. Note that there are no tables (FROM clause) in your query, context: required_names: 'a' source_tables: table_aliases: private_aliases: column_aliases: public_columns: 'a' masked_columns: array_join_columns: source_columns: , e.what() = DB::Exception
+```
+
+If you start `clickhouse-client` with the `stack-trace` parameter, ClickHouse returns the server stack trace with the description of an error.
+
+You might see a message about a broken connection. In this case, you can repeat the query. If the connection breaks every time you perform the query, check the server logs for errors.
+
+## Efficiency of Query Processing {#troubleshooting-too-slow}
+
+If you see that ClickHouse is working too slowly, you need to profile the load on the server resources and network for your queries.
+
+You can use the clickhouse-benchmark utility to profile queries. It shows the number of queries processed per second, the number of rows processed per second, and percentiles of query processing times.
diff --git a/docs/en/reference/operations/update.md b/docs/en/reference/operations/update.md
new file mode 100644
index 00000000000..fb5fb7803a9
--- /dev/null
+++ b/docs/en/reference/operations/update.md
@@ -0,0 +1,32 @@
+---
+sidebar_position: 47
+sidebar_label: ClickHouse Upgrade
+---
+
+# ClickHouse Upgrade {#clickhouse-upgrade}
+
+If ClickHouse was installed from `deb` packages, execute the following commands on the server:
+
+``` bash
+$ sudo apt-get update
+$ sudo apt-get install clickhouse-client clickhouse-server
+$ sudo service clickhouse-server restart
+```
+
+If you installed ClickHouse using something other than the recommended `deb` packages, use the appropriate update method.
+
+:::note    
+You can update multiple servers at once as soon as there is no moment when all replicas of one shard are offline.
+:::
+
+The upgrade of older version of ClickHouse to specific version:
+
+As an example:
+
+`xx.yy.a.b` is a current stable version. The latest stable version could be found [here](https://github.com/ClickHouse/ClickHouse/releases)
+
+```bash
+$ sudo apt-get update
+$ sudo apt-get install clickhouse-server=xx.yy.a.b clickhouse-client=xx.yy.a.b clickhouse-common-static=xx.yy.a.b
+$ sudo service clickhouse-server restart
+```
diff --git a/docs/en/reference/operations/utilities/clickhouse-benchmark.md b/docs/en/reference/operations/utilities/clickhouse-benchmark.md
new file mode 100644
index 00000000000..3a52ec92dc3
--- /dev/null
+++ b/docs/en/reference/operations/utilities/clickhouse-benchmark.md
@@ -0,0 +1,163 @@
+---
+sidebar_position: 61
+sidebar_label: clickhouse-benchmark
+---
+
+# clickhouse-benchmark 
+
+Connects to a ClickHouse server and repeatedly sends specified queries.
+
+**Syntax**
+
+``` bash
+$ clickhouse-benchmark --query ["single query"] [keys]
+```
+
+or
+
+``` bash
+$ echo "single query" | clickhouse-benchmark [keys]
+```
+
+or
+
+``` bash
+$ clickhouse-benchmark [keys] <<< "single query"
+```
+
+If you want to send a set of queries, create a text file and place each query on the individual string in this file. For example:
+
+``` sql
+SELECT * FROM system.numbers LIMIT 10000000;
+SELECT 1;
+```
+
+Then pass this file to a standard input of `clickhouse-benchmark`:
+
+``` bash
+clickhouse-benchmark [keys] < queries_file;
+```
+
+## Keys {#clickhouse-benchmark-keys}
+
+-   `--query=QUERY` — Query to execute. If this parameter is not passed, `clickhouse-benchmark` will read queries from standard input.
+-   `-c N`, `--concurrency=N` — Number of queries that `clickhouse-benchmark` sends simultaneously. Default value: 1.
+-   `-d N`, `--delay=N` — Interval in seconds between intermediate reports (to disable reports set 0). Default value: 1.
+-   `-h HOST`, `--host=HOST` — Server host. Default value: `localhost`. For the [comparison mode](#clickhouse-benchmark-comparison-mode) you can use multiple `-h` keys.
+-   `-p N`, `--port=N` — Server port. Default value: 9000. For the [comparison mode](#clickhouse-benchmark-comparison-mode) you can use multiple `-p` keys.
+-   `-i N`, `--iterations=N` — Total number of queries. Default value: 0 (repeat forever).
+-   `-r`, `--randomize` — Random order of queries execution if there is more than one input query.
+-   `-s`, `--secure` — Using `TLS` connection.
+-   `-t N`, `--timelimit=N` — Time limit in seconds. `clickhouse-benchmark` stops sending queries when the specified time limit is reached. Default value: 0 (time limit disabled).
+-   `--confidence=N` — Level of confidence for T-test. Possible values: 0 (80%), 1 (90%), 2 (95%), 3 (98%), 4 (99%), 5 (99.5%). Default value: 5. In the [comparison mode](#clickhouse-benchmark-comparison-mode) `clickhouse-benchmark` performs the [Independent two-sample Student’s t-test](https://en.wikipedia.org/wiki/Student%27s_t-test#Independent_two-sample_t-test) to determine whether the two distributions aren’t different with the selected level of confidence.
+-   `--cumulative` — Printing cumulative data instead of data per interval.
+-   `--database=DATABASE_NAME` — ClickHouse database name. Default value: `default`.
+-   `--json=FILEPATH` — `JSON` output. When the key is set, `clickhouse-benchmark` outputs a report to the specified JSON-file.
+-   `--user=USERNAME` — ClickHouse user name. Default value: `default`.
+-   `--password=PSWD` — ClickHouse user password. Default value: empty string.
+-   `--stacktrace` — Stack traces output. When the key is set, `clickhouse-bencmark` outputs stack traces of exceptions.
+-   `--stage=WORD` — Query processing stage at server. ClickHouse stops query processing and returns an answer to `clickhouse-benchmark` at the specified stage. Possible values: `complete`, `fetch_columns`, `with_mergeable_state`. Default value: `complete`.
+-   `--help` — Shows the help message.
+
+If you want to apply some [settings](../../operations/settings/index.md) for queries, pass them as a key `--<session setting name>= SETTING_VALUE`. For example, `--max_memory_usage=1048576`.
+
+## Output {#clickhouse-benchmark-output}
+
+By default, `clickhouse-benchmark` reports for each `--delay` interval.
+
+Example of the report:
+
+``` text
+Queries executed: 10.
+
+localhost:9000, queries 10, QPS: 6.772, RPS: 67904487.440, MiB/s: 518.070, result RPS: 67721584.984, result MiB/s: 516.675.
+
+0.000%      0.145 sec.
+10.000%     0.146 sec.
+20.000%     0.146 sec.
+30.000%     0.146 sec.
+40.000%     0.147 sec.
+50.000%     0.148 sec.
+60.000%     0.148 sec.
+70.000%     0.148 sec.
+80.000%     0.149 sec.
+90.000%     0.150 sec.
+95.000%     0.150 sec.
+99.000%     0.150 sec.
+99.900%     0.150 sec.
+99.990%     0.150 sec.
+```
+
+In the report you can find:
+
+-   Number of queries in the `Queries executed:` field.
+
+-   Status string containing (in order):
+
+    -   Endpoint of ClickHouse server.
+    -   Number of processed queries.
+    -   QPS: How many queries the server performed per second during a period specified in the `--delay` argument.
+    -   RPS: How many rows the server reads per second during a period specified in the `--delay` argument.
+    -   MiB/s: How many mebibytes the server reads per second during a period specified in the `--delay` argument.
+    -   result RPS: How many rows placed by the server to the result of a query per second during a period specified in the `--delay` argument.
+    -   result MiB/s. How many mebibytes placed by the server to the result of a query per second during a period specified in the `--delay` argument.
+
+-   Percentiles of queries execution time.
+
+## Comparison Mode {#clickhouse-benchmark-comparison-mode}
+
+`clickhouse-benchmark` can compare performances for two running ClickHouse servers.
+
+To use the comparison mode, specify endpoints of both servers by two pairs of `--host`, `--port` keys. Keys matched together by position in arguments list, the first `--host` is matched with the first `--port` and so on. `clickhouse-benchmark` establishes connections to both servers, then sends queries. Each query addressed to a randomly selected server. The results are shown for each server separately.
+
+## Example {#clickhouse-benchmark-example}
+
+``` bash
+$ echo "SELECT * FROM system.numbers LIMIT 10000000 OFFSET 10000000" | clickhouse-benchmark -i 10
+```
+
+``` text
+Loaded 1 queries.
+
+Queries executed: 6.
+
+localhost:9000, queries 6, QPS: 6.153, RPS: 123398340.957, MiB/s: 941.455, result RPS: 61532982.200, result MiB/s: 469.459.
+
+0.000%      0.159 sec.
+10.000%     0.159 sec.
+20.000%     0.159 sec.
+30.000%     0.160 sec.
+40.000%     0.160 sec.
+50.000%     0.162 sec.
+60.000%     0.164 sec.
+70.000%     0.165 sec.
+80.000%     0.166 sec.
+90.000%     0.166 sec.
+95.000%     0.167 sec.
+99.000%     0.167 sec.
+99.900%     0.167 sec.
+99.990%     0.167 sec.
+
+
+
+Queries executed: 10.
+
+localhost:9000, queries 10, QPS: 6.082, RPS: 121959604.568, MiB/s: 930.478, result RPS: 60815551.642, result MiB/s: 463.986.
+
+0.000%      0.159 sec.
+10.000%     0.159 sec.
+20.000%     0.160 sec.
+30.000%     0.163 sec.
+40.000%     0.164 sec.
+50.000%     0.165 sec.
+60.000%     0.166 sec.
+70.000%     0.166 sec.
+80.000%     0.167 sec.
+90.000%     0.167 sec.
+95.000%     0.170 sec.
+99.000%     0.172 sec.
+99.900%     0.172 sec.
+99.990%     0.172 sec.
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/utilities/clickhouse-benchmark.md) <!--hide-->
diff --git a/docs/en/reference/operations/utilities/clickhouse-compressor.md b/docs/en/reference/operations/utilities/clickhouse-compressor.md
new file mode 100644
index 00000000000..2f8f4794ba8
--- /dev/null
+++ b/docs/en/reference/operations/utilities/clickhouse-compressor.md
@@ -0,0 +1,28 @@
+
+# clickhouse-compressor 
+
+Simple program for data compression and decompression.
+
+### Examples
+
+Compress data with LZ4:
+```
+$ ./clickhouse-compressor < input_file > output_file
+```
+
+Decompress data from LZ4 format:
+```
+$ ./clickhouse-compressor --decompress < input_file > output_file
+```
+
+Compress data with ZSTD at level 5:
+
+```
+$ ./clickhouse-compressor --codec 'ZSTD(5)' < input_file > output_file
+```
+
+Compress data with Delta of four bytes and ZSTD level 10.
+
+```
+$ ./clickhouse-compressor --codec 'Delta(4)' --codec 'ZSTD(10)' < input_file > output_file
+```
diff --git a/docs/en/reference/operations/utilities/clickhouse-copier.md b/docs/en/reference/operations/utilities/clickhouse-copier.md
new file mode 100644
index 00000000000..f152c177992
--- /dev/null
+++ b/docs/en/reference/operations/utilities/clickhouse-copier.md
@@ -0,0 +1,188 @@
+---
+sidebar_position: 59
+sidebar_label: clickhouse-copier
+---
+
+# clickhouse-copier 
+
+Copies data from the tables in one cluster to tables in another (or the same) cluster.
+
+:::warning    
+To get a consistent copy, the data in the source tables and partitions should not change during the entire process.
+:::
+
+You can run multiple `clickhouse-copier` instances on different servers to perform the same job. ZooKeeper is used for syncing the processes.
+
+After starting, `clickhouse-copier`:
+
+-   Connects to ZooKeeper and receives:
+
+    -   Copying jobs.
+    -   The state of the copying jobs.
+
+-   It performs the jobs.
+
+    Each running process chooses the “closest” shard of the source cluster and copies the data into the destination cluster, resharding the data if necessary.
+
+`clickhouse-copier` tracks the changes in ZooKeeper and applies them on the fly.
+
+To reduce network traffic, we recommend running `clickhouse-copier` on the same server where the source data is located.
+
+## Running Clickhouse-copier {#running-clickhouse-copier}
+
+The utility should be run manually:
+
+``` bash
+$ clickhouse-copier --daemon --config zookeeper.xml --task-path /task/path --base-dir /path/to/dir
+```
+
+Parameters:
+
+-   `daemon` — Starts `clickhouse-copier` in daemon mode.
+-   `config` — The path to the `zookeeper.xml` file with the parameters for the connection to ZooKeeper.
+-   `task-path` — The path to the ZooKeeper node. This node is used for syncing `clickhouse-copier` processes and storing tasks. Tasks are stored in `$task-path/description`.
+-   `task-file` — Optional path to file with task configuration for initial upload to ZooKeeper.
+-   `task-upload-force` — Force upload `task-file` even if node already exists.
+-   `base-dir` — The path to logs and auxiliary files. When it starts, `clickhouse-copier` creates `clickhouse-copier_YYYYMMHHSS_<PID>` subdirectories in `$base-dir`. If this parameter is omitted, the directories are created in the directory where `clickhouse-copier` was launched.
+
+## Format of Zookeeper.xml {#format-of-zookeeper-xml}
+
+``` xml
+<clickhouse>
+    <logger>
+        <level>trace</level>
+        <size>100M</size>
+        <count>3</count>
+    </logger>
+
+    <zookeeper>
+        <node index="1">
+            <host>127.0.0.1</host>
+            <port>2181</port>
+        </node>
+    </zookeeper>
+</clickhouse>
+```
+
+## Configuration of Copying Tasks {#configuration-of-copying-tasks}
+
+``` xml
+<clickhouse>
+    <!-- Configuration of clusters as in an ordinary server config -->
+    <remote_servers>
+        <source_cluster>
+            <!--
+                source cluster & destination clusters accept exactly the same
+                parameters as parameters for the usual Distributed table
+                see https://clickhouse.com/docs/en/engines/table-engines/special/distributed/
+            -->
+            <shard>
+                <internal_replication>false</internal_replication>
+                    <replica>
+                        <host>127.0.0.1</host>
+                        <port>9000</port>
+                        <!--
+                        <user>default</user>
+                        <password>default</password>
+                        <secure>1</secure>
+                        -->
+                    </replica>
+            </shard>
+            ...
+        </source_cluster>
+
+        <destination_cluster>
+        ...
+        </destination_cluster>
+    </remote_servers>
+
+    <!-- How many simultaneously active workers are possible. If you run more workers superfluous workers will sleep. -->
+    <max_workers>2</max_workers>
+
+    <!-- Setting used to fetch (pull) data from source cluster tables -->
+    <settings_pull>
+        <readonly>1</readonly>
+    </settings_pull>
+
+    <!-- Setting used to insert (push) data to destination cluster tables -->
+    <settings_push>
+        <readonly>0</readonly>
+    </settings_push>
+
+    <!-- Common setting for fetch (pull) and insert (push) operations. Also, copier process context uses it.
+         They are overlaid by <settings_pull/> and <settings_push/> respectively. -->
+    <settings>
+        <connect_timeout>3</connect_timeout>
+        <!-- Sync insert is set forcibly, leave it here just in case. -->
+        <insert_distributed_sync>1</insert_distributed_sync>
+    </settings>
+
+    <!-- Copying tasks description.
+         You could specify several table task in the same task description (in the same ZooKeeper node), they will be performed
+         sequentially.
+    -->
+    <tables>
+        <!-- A table task, copies one table. -->
+        <table_hits>
+            <!-- Source cluster name (from <remote_servers/> section) and tables in it that should be copied -->
+            <cluster_pull>source_cluster</cluster_pull>
+            <database_pull>test</database_pull>
+            <table_pull>hits</table_pull>
+
+            <!-- Destination cluster name and tables in which the data should be inserted -->
+            <cluster_push>destination_cluster</cluster_push>
+            <database_push>test</database_push>
+            <table_push>hits2</table_push>
+
+            <!-- Engine of destination tables.
+                 If destination tables have not be created, workers create them using columns definition from source tables and engine
+                 definition from here.
+
+                 NOTE: If the first worker starts insert data and detects that destination partition is not empty then the partition will
+                 be dropped and refilled, take it into account if you already have some data in destination tables. You could directly
+                 specify partitions that should be copied in <enabled_partitions/>, they should be in quoted format like partition column of
+                 system.parts table.
+            -->
+            <engine>
+            ENGINE=ReplicatedMergeTree('/clickhouse/tables/{cluster}/{shard}/hits2', '{replica}')
+            PARTITION BY toMonday(date)
+            ORDER BY (CounterID, EventDate)
+            </engine>
+
+            <!-- Sharding key used to insert data to destination cluster -->
+            <sharding_key>jumpConsistentHash(intHash64(UserID), 2)</sharding_key>
+
+            <!-- Optional expression that filter data while pull them from source servers -->
+            <where_condition>CounterID != 0</where_condition>
+
+            <!-- This section specifies partitions that should be copied, other partition will be ignored.
+                 Partition names should have the same format as
+                 partition column of system.parts table (i.e. a quoted text).
+                 Since partition key of source and destination cluster could be different,
+                 these partition names specify destination partitions.
+
+                 NOTE: In spite of this section is optional (if it is not specified, all partitions will be copied),
+                 it is strictly recommended to specify them explicitly.
+                 If you already have some ready partitions on destination cluster they
+                 will be removed at the start of the copying since they will be interpeted
+                 as unfinished data from the previous copying!!!
+            -->
+            <enabled_partitions>
+                <partition>'2018-02-26'</partition>
+                <partition>'2018-03-05'</partition>
+                ...
+            </enabled_partitions>
+        </table_hits>
+
+        <!-- Next table to copy. It is not copied until previous table is copying. -->
+        <table_visits>
+        ...
+        </table_visits>
+        ...
+    </tables>
+</clickhouse>
+```
+
+`clickhouse-copier` tracks the changes in `/task/path/description` and applies them on the fly. For instance, if you change the value of `max_workers`, the number of processes running tasks will also change.
+
+[Original article](https://clickhouse.com/docs/en/operations/utils/clickhouse-copier/) <!--hide-->
diff --git a/docs/en/reference/operations/utilities/clickhouse-format.md b/docs/en/reference/operations/utilities/clickhouse-format.md
new file mode 100644
index 00000000000..219a170fc23
--- /dev/null
+++ b/docs/en/reference/operations/utilities/clickhouse-format.md
@@ -0,0 +1,109 @@
+# clickhouse-format 
+
+Allows formatting input queries.
+
+Keys:
+
+- `--help` or`-h` — Produce help message.
+- `--query` — Format queries of any length and complexity.
+- `--hilite` — Add syntax highlight with ANSI terminal escape sequences.
+- `--oneline` — Format in single line.
+- `--quiet` or `-q` — Just check syntax, no output on success.
+- `--multiquery` or `-n` — Allow multiple queries in the same file.
+- `--obfuscate` — Obfuscate instead of formatting.
+- `--seed <string>` — Seed arbitrary string that determines the result of obfuscation.
+- `--backslash` — Add a backslash at the end of each line of the formatted query. Can be useful when you copy a query from web or somewhere else with multiple lines, and want to execute it in command line.
+
+## Examples {#examples}
+
+1. Formatting a query:
+
+```bash
+$ clickhouse-format --query "select number from numbers(10) where number%2 order by number desc;"
+```
+
+Result:
+
+```text
+SELECT number
+FROM numbers(10)
+WHERE number % 2
+ORDER BY number DESC
+```
+
+2. Highlighting and single line:
+
+```bash
+$ clickhouse-format --oneline --hilite <<< "SELECT sum(number) FROM numbers(5);"
+```
+
+Result:
+
+```sql
+SELECT sum(number) FROM numbers(5)
+```
+
+3. Multiqueries:
+
+```bash
+$ clickhouse-format -n <<< "SELECT * FROM (SELECT 1 AS x UNION ALL SELECT 1 UNION DISTINCT SELECT 3);"
+```
+
+Result:
+
+```text
+SELECT *
+FROM
+(
+    SELECT 1 AS x
+    UNION ALL
+    SELECT 1
+    UNION DISTINCT
+    SELECT 3
+)
+;
+```
+
+4. Obfuscating:
+
+```bash
+$ clickhouse-format --seed Hello --obfuscate <<< "SELECT cost_first_screen BETWEEN a AND b, CASE WHEN x >= 123 THEN y ELSE NULL END;"
+```
+
+Result:
+
+```text
+SELECT treasury_mammoth_hazelnut BETWEEN nutmeg AND span, CASE WHEN chive >= 116 THEN switching ELSE ANYTHING END;
+```
+
+Same query and another seed string:
+
+```bash
+$ clickhouse-format --seed World --obfuscate <<< "SELECT cost_first_screen BETWEEN a AND b, CASE WHEN x >= 123 THEN y ELSE NULL END;"
+```
+
+Result:
+
+```text
+SELECT horse_tape_summer BETWEEN folklore AND moccasins, CASE WHEN intestine >= 116 THEN nonconformist ELSE FORESTRY END;
+```
+
+5. Adding backslash:
+
+```bash
+$ clickhouse-format --backslash <<< "SELECT * FROM (SELECT 1 AS x UNION ALL SELECT 1 UNION DISTINCT SELECT 3);"
+```
+
+Result:
+
+```text
+SELECT * \
+FROM  \
+( \
+    SELECT 1 AS x \
+    UNION ALL \
+    SELECT 1 \
+    UNION DISTINCT \
+    SELECT 3 \
+)
+```
diff --git a/docs/en/reference/operations/utilities/clickhouse-local.md b/docs/en/reference/operations/utilities/clickhouse-local.md
new file mode 100644
index 00000000000..3c35ab933e2
--- /dev/null
+++ b/docs/en/reference/operations/utilities/clickhouse-local.md
@@ -0,0 +1,118 @@
+---
+sidebar_position: 60
+sidebar_label: clickhouse-local
+---
+
+# clickhouse-local 
+
+The `clickhouse-local` program enables you to perform fast processing on local files, without having to deploy and configure the ClickHouse server.
+
+Accepts data that represent tables and queries them using [ClickHouse SQL dialect](../../sql-reference/index.md).
+
+`clickhouse-local` uses the same core as ClickHouse server, so it supports most of the features and the same set of formats and table engines.
+
+By default `clickhouse-local` does not have access to data on the same host, but it supports loading server configuration using `--config-file` argument.
+
+:::warning
+It is not recommended to load production server configuration into `clickhouse-local` because data can be damaged in case of human error.
+:::
+
+For temporary data, a unique temporary data directory is created by default.
+
+## Usage {#usage}
+
+Basic usage:
+
+``` bash
+$ clickhouse-local --structure "table_structure" --input-format "format_of_incoming_data" \
+    --query "query"
+```
+
+Arguments:
+
+-   `-S`, `--structure` — table structure for input data.
+-   `-if`, `--input-format` — input format, `TSV` by default.
+-   `-f`, `--file` — path to data, `stdin` by default.
+-   `-q`, `--query` — queries to execute with `;` as delimeter. You must specify either `query` or `queries-file` option.
+-   `-qf`, `--queries-file` - file path with queries to execute. You must specify either `query` or `queries-file` option.
+-   `-N`, `--table` — table name where to put output data, `table` by default.
+-   `-of`, `--format`, `--output-format` — output format, `TSV` by default.
+-   `-d`, `--database` — default database, `_local` by default.
+-   `--stacktrace` — whether to dump debug output in case of exception.
+-   `--echo` — print query before execution.
+-   `--verbose` — more details on query execution.
+-   `--logger.console` — Log to console.
+-   `--logger.log` — Log file name.
+-   `--logger.level` — Log level.
+-   `--ignore-error` — do not stop processing if a query failed.
+-   `-c`, `--config-file` — path to configuration file in same format as for ClickHouse server, by default the configuration empty.
+-   `--no-system-tables` — do not attach system tables.
+-   `--help` — arguments references for `clickhouse-local`.
+-   `-V`, `--version` — print version information and exit.
+
+Also there are arguments for each ClickHouse configuration variable which are more commonly used instead of `--config-file`.
+
+
+## Examples {#examples}
+
+``` bash
+$ echo -e "1,2\n3,4" | clickhouse-local --structure "a Int64, b Int64" \
+    --input-format "CSV" --query "SELECT * FROM table"
+Read 2 rows, 32.00 B in 0.000 sec., 5182 rows/sec., 80.97 KiB/sec.
+1   2
+3   4
+```
+
+Previous example is the same as:
+
+``` bash
+$ echo -e "1,2\n3,4" | clickhouse-local --query "
+    CREATE TABLE table (a Int64, b Int64) ENGINE = File(CSV, stdin);
+    SELECT a, b FROM table;
+    DROP TABLE table"
+Read 2 rows, 32.00 B in 0.000 sec., 4987 rows/sec., 77.93 KiB/sec.
+1   2
+3   4
+```
+
+You don't have to use `stdin` or `--file` argument, and can open any number of files using the [`file` table function](../../sql-reference/table-functions/file.md):
+
+``` bash
+$ echo 1 | tee 1.tsv
+1
+
+$ echo 2 | tee 2.tsv
+2
+
+$ clickhouse-local --query "
+    select * from file('1.tsv', TSV, 'a int') t1
+    cross join file('2.tsv', TSV, 'b int') t2"
+1	2
+```
+
+Now let’s output memory user for each Unix user:
+
+Query:
+
+``` bash
+$ ps aux | tail -n +2 | awk '{ printf("%s\t%s\n", $1, $4) }' \
+    | clickhouse-local --structure "user String, mem Float64" \
+        --query "SELECT user, round(sum(mem), 2) as memTotal
+            FROM table GROUP BY user ORDER BY memTotal DESC FORMAT Pretty"
+```
+
+Result:
+
+``` text
+Read 186 rows, 4.15 KiB in 0.035 sec., 5302 rows/sec., 118.34 KiB/sec.
+┏━━━━━━━━━━┳━━━━━━━━━━┓
+┃ user     ┃ memTotal ┃
+┡━━━━━━━━━━╇━━━━━━━━━━┩
+│ bayonet  │    113.5 │
+├──────────┼──────────┤
+│ root     │      8.8 │
+├──────────┼──────────┤
+...
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/utils/clickhouse-local/) <!--hide-->
diff --git a/docs/en/reference/operations/utilities/clickhouse-obfuscator.md b/docs/en/reference/operations/utilities/clickhouse-obfuscator.md
new file mode 100644
index 00000000000..baa0f19dda9
--- /dev/null
+++ b/docs/en/reference/operations/utilities/clickhouse-obfuscator.md
@@ -0,0 +1,42 @@
+# clickhouse-obfuscator 
+
+A simple tool for table data obfuscation.
+
+It reads an input table and produces an output table, that retains some properties of input, but contains different data.
+It allows publishing almost real production data for usage in benchmarks.
+
+It is designed to retain the following properties of data:
+- cardinalities of values (number of distinct values) for every column and every tuple of columns;
+- conditional cardinalities: number of distinct values of one column under the condition on the value of another column;
+- probability distributions of the absolute value of integers; the sign of signed integers; exponent and sign for floats;
+- probability distributions of the length of strings;
+- probability of zero values of numbers; empty strings and arrays, `NULL`s;
+
+- data compression ratio when compressed with LZ77 and entropy family of codecs;
+- continuity (magnitude of difference) of time values across the table; continuity of floating-point values;
+- date component of `DateTime` values;
+
+- UTF-8 validity of string values;
+- string values look natural.
+
+Most of the properties above are viable for performance testing:
+
+reading data, filtering, aggregatio, and sorting will work at almost the same speed
+as on original data due to saved cardinalities, magnitudes, compression ratios, etc.
+
+It works in a deterministic fashion: you define a seed value and the transformation is determined by input data and by seed.
+Some transformations are one to one and could be reversed, so you need to have a large seed and keep it in secret.
+
+It uses some cryptographic primitives to transform data but from the cryptographic point of view, it does not do it properly, that is why you should not consider the result as secure unless you have another reason. The result may retain some data you don't want to publish.
+
+
+It always leaves 0, 1, -1 numbers, dates, lengths of arrays, and null flags exactly as in source data.
+For example, you have a column `IsMobile` in your table with values 0 and 1. In transformed data, it will have the same value.
+
+So, the user will be able to count the exact ratio of mobile traffic.
+
+Let's give another example. When you have some private data in your table, like user email and you don't want to publish any single email address.
+If your table is large enough and contains multiple different emails and no email has a very high frequency than all others, it will anonymize all data. But if you have a small number of different values in a column, it can reproduce some of them.
+You should look at the working algorithm of this tool works, and fine-tune its command line parameters.
+
+This tool works fine only with an average amount of data (at least 1000s of rows).
diff --git a/docs/en/reference/operations/utilities/index.md b/docs/en/reference/operations/utilities/index.md
new file mode 100644
index 00000000000..7fdc783f9c4
--- /dev/null
+++ b/docs/en/reference/operations/utilities/index.md
@@ -0,0 +1,15 @@
+---
+sidebar_position: 56
+sidebar_label: Utilities
+---
+
+# ClickHouse Utility 
+
+-   [clickhouse-local](../../operations/utilities/clickhouse-local.md) — Allows running SQL queries on data without starting the ClickHouse server, similar to how `awk` does this.
+-   [clickhouse-copier](../../operations/utilities/clickhouse-copier.md) — Copies (and reshards) data from one cluster to another cluster.
+-   [clickhouse-benchmark](../../operations/utilities/clickhouse-benchmark.md) — Loads server with the custom queries and settings.
+-   [clickhouse-format](../../operations/utilities/clickhouse-format.md) — Enables formatting input queries.
+-   [ClickHouse obfuscator](../../operations/utilities/clickhouse-obfuscator.md) — Obfuscates data.
+-   [ClickHouse compressor](../../operations/utilities/clickhouse-compressor.md) — Compresses and decompresses data.
+-   [clickhouse-odbc-bridge](../../operations/utilities/odbc-bridge.md) — A proxy server for ODBC driver.
+
diff --git a/docs/en/reference/operations/utilities/odbc-bridge.md b/docs/en/reference/operations/utilities/odbc-bridge.md
new file mode 100644
index 00000000000..e5967085c49
--- /dev/null
+++ b/docs/en/reference/operations/utilities/odbc-bridge.md
@@ -0,0 +1,38 @@
+# clickhouse-odbc-bridge
+
+Simple HTTP-server which works like a proxy for ODBC driver. The main motivation
+was possible segfaults or another faults in ODBC implementations, which can
+crash whole clickhouse-server process.
+
+This tool works via HTTP, not via pipes, shared memory, or TCP because:
+- It's simpler to implement
+- It's simpler to debug
+- jdbc-bridge can be implemented in the same way
+
+## Usage
+
+`clickhouse-server` use this tool inside odbc table function and StorageODBC.
+However it can be used as standalone tool from command line with the following
+parameters in POST-request URL:
+- `connection_string` -- ODBC connection string.
+- `columns` -- columns in ClickHouse NamesAndTypesList format, name in backticks,
+  type as string. Name and type are space separated, rows separated with
+  newline.
+- `max_block_size` -- optional parameter, sets maximum size of single block.
+Query is send in post body. Response is returned in RowBinary format.
+
+## Example:
+
+```bash
+$ clickhouse-odbc-bridge --http-port 9018 --daemon
+
+$ curl -d "query=SELECT PageID, ImpID, AdType FROM Keys ORDER BY PageID, ImpID" --data-urlencode "connection_string=DSN=ClickHouse;DATABASE=stat" --data-urlencode "sample_block=columns format version: 1
+3 columns:
+\`PageID\` String
+\`ImpID\` String
+\`AdType\` String
+"  "http://localhost:9018/" > result.txt
+
+$ cat result.txt
+12246623837185725195925621517
+```
diff --git a/docs/en/reference/sql-reference/_category_.yml b/docs/en/reference/sql-reference/_category_.yml
new file mode 100644
index 00000000000..8c5a40b6a85
--- /dev/null
+++ b/docs/en/reference/sql-reference/_category_.yml
@@ -0,0 +1,4 @@
+position: 15
+label: 'SQL Reference'
+collapsible: true
+collapsed: true
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/combinators.md b/docs/en/reference/sql-reference/aggregate-functions/combinators.md
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+---
+sidebar_position: 37
+sidebar_label: Combinators
+---
+
+# Aggregate Function Combinators {#aggregate_functions_combinators}
+
+The name of an aggregate function can have a suffix appended to it. This changes the way the aggregate function works.
+
+## -If {#agg-functions-combinator-if}
+
+The suffix -If can be appended to the name of any aggregate function. In this case, the aggregate function accepts an extra argument – a condition (Uint8 type). The aggregate function processes only the rows that trigger the condition. If the condition was not triggered even once, it returns a default value (usually zeros or empty strings).
+
+Examples: `sumIf(column, cond)`, `countIf(cond)`, `avgIf(x, cond)`, `quantilesTimingIf(level1, level2)(x, cond)`, `argMinIf(arg, val, cond)` and so on.
+
+With conditional aggregate functions, you can calculate aggregates for several conditions at once, without using subqueries and `JOIN`s. For example, conditional aggregate functions can be used to implement the segment comparison functionality.
+
+## -Array {#agg-functions-combinator-array}
+
+The -Array suffix can be appended to any aggregate function. In this case, the aggregate function takes arguments of the ‘Array(T)’ type (arrays) instead of ‘T’ type arguments. If the aggregate function accepts multiple arguments, this must be arrays of equal lengths. When processing arrays, the aggregate function works like the original aggregate function across all array elements.
+
+Example 1: `sumArray(arr)` - Totals all the elements of all ‘arr’ arrays. In this example, it could have been written more simply: `sum(arraySum(arr))`.
+
+Example 2: `uniqArray(arr)` – Counts the number of unique elements in all ‘arr’ arrays. This could be done an easier way: `uniq(arrayJoin(arr))`, but it’s not always possible to add ‘arrayJoin’ to a query.
+
+-If and -Array can be combined. However, ‘Array’ must come first, then ‘If’. Examples: `uniqArrayIf(arr, cond)`, `quantilesTimingArrayIf(level1, level2)(arr, cond)`. Due to this order, the ‘cond’ argument won’t be an array.
+
+## -Map {#agg-functions-combinator-map}
+
+The -Map suffix can be appended to any aggregate function. This will create an aggregate function which gets Map type as an argument, and aggregates values of each key of the map separately using the specified aggregate function. The result is also of a Map type.
+
+Examples: `sumMap(map(1,1))`, `avgMap(map('a', 1))`.
+
+## -SimpleState {#agg-functions-combinator-simplestate}
+
+If you apply this combinator, the aggregate function returns the same value but with a different type. This is a [SimpleAggregateFunction(...)](../../sql-reference/data-types/simpleaggregatefunction.md) that can be stored in a table to work with [AggregatingMergeTree](../../engines/table-engines/mergetree-family/aggregatingmergetree.md) tables.
+
+**Syntax**
+
+``` sql
+<aggFunction>SimpleState(x)
+```
+
+**Arguments**
+
+-   `x` — Aggregate function parameters.
+
+**Returned values**
+
+The value of an aggregate function with the `SimpleAggregateFunction(...)` type.
+
+**Example**
+
+Query:
+
+``` sql
+WITH anySimpleState(number) AS c SELECT toTypeName(c), c FROM numbers(1);
+```
+
+Result:
+
+``` text
+┌─toTypeName(c)────────────────────────┬─c─┐
+│ SimpleAggregateFunction(any, UInt64) │ 0 │
+└──────────────────────────────────────┴───┘
+```
+
+## -State {#agg-functions-combinator-state}
+
+If you apply this combinator, the aggregate function does not return the resulting value (such as the number of unique values for the [uniq](../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq) function), but an intermediate state of the aggregation (for `uniq`, this is the hash table for calculating the number of unique values). This is an `AggregateFunction(...)` that can be used for further processing or stored in a table to finish aggregating later.
+
+To work with these states, use:
+
+-   [AggregatingMergeTree](../../engines/table-engines/mergetree-family/aggregatingmergetree.md) table engine.
+-   [finalizeAggregation](../../sql-reference/functions/other-functions.md#function-finalizeaggregation) function.
+-   [runningAccumulate](../../sql-reference/functions/other-functions.md#runningaccumulate) function.
+-   [-Merge](#aggregate_functions_combinators-merge) combinator.
+-   [-MergeState](#aggregate_functions_combinators-mergestate) combinator.
+
+## -Merge {#aggregate_functions_combinators-merge}
+
+If you apply this combinator, the aggregate function takes the intermediate aggregation state as an argument, combines the states to finish aggregation, and returns the resulting value.
+
+## -MergeState {#aggregate_functions_combinators-mergestate}
+
+Merges the intermediate aggregation states in the same way as the -Merge combinator. However, it does not return the resulting value, but an intermediate aggregation state, similar to the -State combinator.
+
+## -ForEach {#agg-functions-combinator-foreach}
+
+Converts an aggregate function for tables into an aggregate function for arrays that aggregates the corresponding array items and returns an array of results. For example, `sumForEach` for the arrays `[1, 2]`, `[3, 4, 5]`and`[6, 7]`returns the result `[10, 13, 5]` after adding together the corresponding array items.
+
+## -Distinct {#agg-functions-combinator-distinct}
+
+Every unique combination of arguments will be aggregated only once. Repeating values are ignored.
+Examples: `sum(DISTINCT x)`, `groupArray(DISTINCT x)`, `corrStableDistinct(DISTINCT x, y)` and so on.
+
+## -OrDefault {#agg-functions-combinator-ordefault}
+
+Changes behavior of an aggregate function.
+
+If an aggregate function does not have input values, with this combinator it returns the default value for its return data type. Applies to the aggregate functions that can take empty input data.
+
+`-OrDefault` can be used with other combinators.
+
+**Syntax**
+
+``` sql
+<aggFunction>OrDefault(x)
+```
+
+**Arguments**
+
+-   `x` — Aggregate function parameters.
+
+**Returned values**
+
+Returns the default value of an aggregate function’s return type if there is nothing to aggregate.
+
+Type depends on the aggregate function used.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT avg(number), avgOrDefault(number) FROM numbers(0)
+```
+
+Result:
+
+``` text
+┌─avg(number)─┬─avgOrDefault(number)─┐
+│         nan │                    0 │
+└─────────────┴──────────────────────┘
+```
+
+Also `-OrDefault` can be used with another combinators. It is useful when the aggregate function does not accept the empty input.
+
+Query:
+
+``` sql
+SELECT avgOrDefaultIf(x, x > 10)
+FROM
+(
+    SELECT toDecimal32(1.23, 2) AS x
+)
+```
+
+Result:
+
+``` text
+┌─avgOrDefaultIf(x, greater(x, 10))─┐
+│                              0.00 │
+└───────────────────────────────────┘
+```
+
+## -OrNull {#agg-functions-combinator-ornull}
+
+Changes behavior of an aggregate function.
+
+This combinator converts a result of an aggregate function to the [Nullable](../../sql-reference/data-types/nullable.md) data type. If the aggregate function does not have values to calculate it returns [NULL](../../sql-reference/syntax.md#null-literal).
+
+`-OrNull` can be used with other combinators.
+
+**Syntax**
+
+``` sql
+<aggFunction>OrNull(x)
+```
+
+**Arguments**
+
+-   `x` — Aggregate function parameters.
+
+**Returned values**
+
+-   The result of the aggregate function, converted to the `Nullable` data type.
+-   `NULL`, if there is nothing to aggregate.
+
+Type: `Nullable(aggregate function return type)`.
+
+**Example**
+
+Add `-orNull` to the end of aggregate function.
+
+Query:
+
+``` sql
+SELECT sumOrNull(number), toTypeName(sumOrNull(number)) FROM numbers(10) WHERE number > 10
+```
+
+Result:
+
+``` text
+┌─sumOrNull(number)─┬─toTypeName(sumOrNull(number))─┐
+│              ᴺᵁᴸᴸ │ Nullable(UInt64)              │
+└───────────────────┴───────────────────────────────┘
+```
+
+Also `-OrNull` can be used with another combinators. It is useful when the aggregate function does not accept the empty input.
+
+Query:
+
+``` sql
+SELECT avgOrNullIf(x, x > 10)
+FROM
+(
+    SELECT toDecimal32(1.23, 2) AS x
+)
+```
+
+Result:
+
+``` text
+┌─avgOrNullIf(x, greater(x, 10))─┐
+│                           ᴺᵁᴸᴸ │
+└────────────────────────────────┘
+```
+
+## -Resample {#agg-functions-combinator-resample}
+
+Lets you divide data into groups, and then separately aggregates the data in those groups. Groups are created by splitting the values from one column into intervals.
+
+``` sql
+<aggFunction>Resample(start, end, step)(<aggFunction_params>, resampling_key)
+```
+
+**Arguments**
+
+-   `start` — Starting value of the whole required interval for `resampling_key` values.
+-   `stop` — Ending value of the whole required interval for `resampling_key` values. The whole interval does not include the `stop` value `[start, stop)`.
+-   `step` — Step for separating the whole interval into subintervals. The `aggFunction` is executed over each of those subintervals independently.
+-   `resampling_key` — Column whose values are used for separating data into intervals.
+-   `aggFunction_params` — `aggFunction` parameters.
+
+**Returned values**
+
+-   Array of `aggFunction` results for each subinterval.
+
+**Example**
+
+Consider the `people` table with the following data:
+
+``` text
+┌─name───┬─age─┬─wage─┐
+│ John   │  16 │   10 │
+│ Alice  │  30 │   15 │
+│ Mary   │  35 │    8 │
+│ Evelyn │  48 │ 11.5 │
+│ David  │  62 │  9.9 │
+│ Brian  │  60 │   16 │
+└────────┴─────┴──────┘
+```
+
+Let’s get the names of the people whose age lies in the intervals of `[30,60)` and `[60,75)`. Since we use integer representation for age, we get ages in the `[30, 59]` and `[60,74]` intervals.
+
+To aggregate names in an array, we use the [groupArray](../../sql-reference/aggregate-functions/reference/grouparray.md#agg_function-grouparray) aggregate function. It takes one argument. In our case, it’s the `name` column. The `groupArrayResample` function should use the `age` column to aggregate names by age. To define the required intervals, we pass the `30, 75, 30` arguments into the `groupArrayResample` function.
+
+``` sql
+SELECT groupArrayResample(30, 75, 30)(name, age) FROM people
+```
+
+``` text
+┌─groupArrayResample(30, 75, 30)(name, age)─────┐
+│ [['Alice','Mary','Evelyn'],['David','Brian']] │
+└───────────────────────────────────────────────┘
+```
+
+Consider the results.
+
+`Jonh` is out of the sample because he’s too young. Other people are distributed according to the specified age intervals.
+
+Now let’s count the total number of people and their average wage in the specified age intervals.
+
+``` sql
+SELECT
+    countResample(30, 75, 30)(name, age) AS amount,
+    avgResample(30, 75, 30)(wage, age) AS avg_wage
+FROM people
+```
+
+``` text
+┌─amount─┬─avg_wage──────────────────┐
+│ [3,2]  │ [11.5,12.949999809265137] │
+└────────┴───────────────────────────┘
+```
+
diff --git a/docs/en/reference/sql-reference/aggregate-functions/index.md b/docs/en/reference/sql-reference/aggregate-functions/index.md
new file mode 100644
index 00000000000..1e6cc0f88c2
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/index.md
@@ -0,0 +1,60 @@
+---
+sidebar_label: Aggregate Functions
+sidebar_position: 33
+---
+
+# Aggregate Functions 
+
+Aggregate functions work in the [normal](http://www.sql-tutorial.com/sql-aggregate-functions-sql-tutorial) way as expected by database experts.
+
+ClickHouse also supports:
+
+-   [Parametric aggregate functions](../../sql-reference/aggregate-functions/parametric-functions.md#aggregate_functions_parametric), which accept other parameters in addition to columns.
+-   [Combinators](../../sql-reference/aggregate-functions/combinators.md#aggregate_functions_combinators), which change the behavior of aggregate functions.
+
+
+## NULL Processing {#null-processing}
+
+During aggregation, all `NULL`s are skipped.
+
+**Examples:**
+
+Consider this table:
+
+``` text
+┌─x─┬────y─┐
+│ 1 │    2 │
+│ 2 │ ᴺᵁᴸᴸ │
+│ 3 │    2 │
+│ 3 │    3 │
+│ 3 │ ᴺᵁᴸᴸ │
+└───┴──────┘
+```
+
+Let’s say you need to total the values in the `y` column:
+
+``` sql
+SELECT sum(y) FROM t_null_big
+```
+
+```text
+┌─sum(y)─┐
+│      7 │
+└────────┘
+```
+
+Now you can use the `groupArray` function to create an array from the `y` column:
+
+``` sql
+SELECT groupArray(y) FROM t_null_big
+```
+
+``` text
+┌─groupArray(y)─┐
+│ [2,2,3]       │
+└───────────────┘
+```
+
+`groupArray` does not include `NULL` in the resulting array.
+
+
diff --git a/docs/en/reference/sql-reference/aggregate-functions/parametric-functions.md b/docs/en/reference/sql-reference/aggregate-functions/parametric-functions.md
new file mode 100644
index 00000000000..7708bcb8129
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/parametric-functions.md
@@ -0,0 +1,766 @@
+---
+sidebar_position: 38
+sidebar_label: Parametric
+---
+
+# Parametric Aggregate Functions {#aggregate_functions_parametric}
+
+Some aggregate functions can accept not only argument columns (used for compression), but a set of parameters – constants for initialization. The syntax is two pairs of brackets instead of one. The first is for parameters, and the second is for arguments.
+
+## histogram {#histogram}
+
+Calculates an adaptive histogram. It does not guarantee precise results.
+
+``` sql
+histogram(number_of_bins)(values)
+```
+
+The functions uses [A Streaming Parallel Decision Tree Algorithm](http://jmlr.org/papers/volume11/ben-haim10a/ben-haim10a.pdf). The borders of histogram bins are adjusted as new data enters a function. In common case, the widths of bins are not equal.
+
+**Arguments**
+
+`values` — [Expression](../../sql-reference/syntax.md#syntax-expressions) resulting in input values.
+
+**Parameters**
+
+`number_of_bins` — Upper limit for the number of bins in the histogram. The function automatically calculates the number of bins. It tries to reach the specified number of bins, but if it fails, it uses fewer bins.
+
+**Returned values**
+
+-   [Array](../../sql-reference/data-types/array.md) of [Tuples](../../sql-reference/data-types/tuple.md) of the following format:
+
+        ```
+        [(lower_1, upper_1, height_1), ... (lower_N, upper_N, height_N)]
+        ```
+
+        - `lower` — Lower bound of the bin.
+        - `upper` — Upper bound of the bin.
+        - `height` — Calculated height of the bin.
+
+**Example**
+
+``` sql
+SELECT histogram(5)(number + 1)
+FROM (
+    SELECT *
+    FROM system.numbers
+    LIMIT 20
+)
+```
+
+``` text
+┌─histogram(5)(plus(number, 1))───────────────────────────────────────────┐
+│ [(1,4.5,4),(4.5,8.5,4),(8.5,12.75,4.125),(12.75,17,4.625),(17,20,3.25)] │
+└─────────────────────────────────────────────────────────────────────────┘
+```
+
+You can visualize a histogram with the [bar](../../sql-reference/functions/other-functions.md#function-bar) function, for example:
+
+``` sql
+WITH histogram(5)(rand() % 100) AS hist
+SELECT
+    arrayJoin(hist).3 AS height,
+    bar(height, 0, 6, 5) AS bar
+FROM
+(
+    SELECT *
+    FROM system.numbers
+    LIMIT 20
+)
+```
+
+``` text
+┌─height─┬─bar───┐
+│  2.125 │ █▋    │
+│   3.25 │ ██▌   │
+│  5.625 │ ████▏ │
+│  5.625 │ ████▏ │
+│  3.375 │ ██▌   │
+└────────┴───────┘
+```
+
+In this case, you should remember that you do not know the histogram bin borders.
+
+## sequenceMatch(pattern)(timestamp, cond1, cond2, …) {#function-sequencematch}
+
+Checks whether the sequence contains an event chain that matches the pattern.
+
+``` sql
+sequenceMatch(pattern)(timestamp, cond1, cond2, ...)
+```
+
+:::warning    
+Events that occur at the same second may lay in the sequence in an undefined order affecting the result.
+:::
+
+**Arguments**
+
+-   `timestamp` — Column considered to contain time data. Typical data types are `Date` and `DateTime`. You can also use any of the supported [UInt](../../sql-reference/data-types/int-uint.md) data types.
+
+-   `cond1`, `cond2` — Conditions that describe the chain of events. Data type: `UInt8`. You can pass up to 32 condition arguments. The function takes only the events described in these conditions into account. If the sequence contains data that isn’t described in a condition, the function skips them.
+
+**Parameters**
+
+-   `pattern` — Pattern string. See [Pattern syntax](#sequence-function-pattern-syntax).
+
+**Returned values**
+
+-   1, if the pattern is matched.
+-   0, if the pattern isn’t matched.
+
+Type: `UInt8`.
+
+<a name="sequence-function-pattern-syntax"></a>
+**Pattern syntax**
+
+-   `(?N)` — Matches the condition argument at position `N`. Conditions are numbered in the `[1, 32]` range. For example, `(?1)` matches the argument passed to the `cond1` parameter.
+
+-   `.*` — Matches any number of events. You do not need conditional arguments to match this element of the pattern.
+
+-   `(?t operator value)` — Sets the time in seconds that should separate two events. For example, pattern `(?1)(?t>1800)(?2)` matches events that occur more than 1800 seconds from each other. An arbitrary number of any events can lay between these events. You can use the `>=`, `>`, `<`, `<=`, `==` operators.
+
+**Examples**
+
+Consider data in the `t` table:
+
+``` text
+┌─time─┬─number─┐
+│    1 │      1 │
+│    2 │      3 │
+│    3 │      2 │
+└──────┴────────┘
+```
+
+Perform the query:
+
+``` sql
+SELECT sequenceMatch('(?1)(?2)')(time, number = 1, number = 2) FROM t
+```
+
+``` text
+┌─sequenceMatch('(?1)(?2)')(time, equals(number, 1), equals(number, 2))─┐
+│                                                                     1 │
+└───────────────────────────────────────────────────────────────────────┘
+```
+
+The function found the event chain where number 2 follows number 1. It skipped number 3 between them, because the number is not described as an event. If we want to take this number into account when searching for the event chain given in the example, we should make a condition for it.
+
+``` sql
+SELECT sequenceMatch('(?1)(?2)')(time, number = 1, number = 2, number = 3) FROM t
+```
+
+``` text
+┌─sequenceMatch('(?1)(?2)')(time, equals(number, 1), equals(number, 2), equals(number, 3))─┐
+│                                                                                        0 │
+└──────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+In this case, the function couldn’t find the event chain matching the pattern, because the event for number 3 occurred between 1 and 2. If in the same case we checked the condition for number 4, the sequence would match the pattern.
+
+``` sql
+SELECT sequenceMatch('(?1)(?2)')(time, number = 1, number = 2, number = 4) FROM t
+```
+
+``` text
+┌─sequenceMatch('(?1)(?2)')(time, equals(number, 1), equals(number, 2), equals(number, 4))─┐
+│                                                                                        1 │
+└──────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [sequenceCount](#function-sequencecount)
+
+## sequenceCount(pattern)(time, cond1, cond2, …) {#function-sequencecount}
+
+Counts the number of event chains that matched the pattern. The function searches event chains that do not overlap. It starts to search for the next chain after the current chain is matched.
+
+:::warning    
+Events that occur at the same second may lay in the sequence in an undefined order affecting the result.
+:::
+
+``` sql
+sequenceCount(pattern)(timestamp, cond1, cond2, ...)
+```
+
+**Arguments**
+
+-   `timestamp` — Column considered to contain time data. Typical data types are `Date` and `DateTime`. You can also use any of the supported [UInt](../../sql-reference/data-types/int-uint.md) data types.
+
+-   `cond1`, `cond2` — Conditions that describe the chain of events. Data type: `UInt8`. You can pass up to 32 condition arguments. The function takes only the events described in these conditions into account. If the sequence contains data that isn’t described in a condition, the function skips them.
+
+**Parameters**
+
+-   `pattern` — Pattern string. See [Pattern syntax](#sequence-function-pattern-syntax).
+
+**Returned values**
+
+-   Number of non-overlapping event chains that are matched.
+
+Type: `UInt64`.
+
+**Example**
+
+Consider data in the `t` table:
+
+``` text
+┌─time─┬─number─┐
+│    1 │      1 │
+│    2 │      3 │
+│    3 │      2 │
+│    4 │      1 │
+│    5 │      3 │
+│    6 │      2 │
+└──────┴────────┘
+```
+
+Count how many times the number 2 occurs after the number 1 with any amount of other numbers between them:
+
+``` sql
+SELECT sequenceCount('(?1).*(?2)')(time, number = 1, number = 2) FROM t
+```
+
+``` text
+┌─sequenceCount('(?1).*(?2)')(time, equals(number, 1), equals(number, 2))─┐
+│                                                                       2 │
+└─────────────────────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [sequenceMatch](#function-sequencematch)
+
+## windowFunnel {#windowfunnel}
+
+Searches for event chains in a sliding time window and calculates the maximum number of events that occurred from the chain.
+
+The function works according to the algorithm:
+
+-   The function searches for data that triggers the first condition in the chain and sets the event counter to 1. This is the moment when the sliding window starts.
+
+-   If events from the chain occur sequentially within the window, the counter is incremented. If the sequence of events is disrupted, the counter isn’t incremented.
+
+-   If the data has multiple event chains at varying points of completion, the function will only output the size of the longest chain.
+
+**Syntax**
+
+``` sql
+windowFunnel(window, [mode, [mode, ... ]])(timestamp, cond1, cond2, ..., condN)
+```
+
+**Arguments**
+
+-   `timestamp` — Name of the column containing the timestamp. Data types supported: [Date](../../sql-reference/data-types/date.md), [DateTime](../../sql-reference/data-types/datetime.md#data_type-datetime) and other unsigned integer types (note that even though timestamp supports the `UInt64` type, it’s value can’t exceed the Int64 maximum, which is 2^63 - 1).
+-   `cond` — Conditions or data describing the chain of events. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Parameters**
+
+-   `window` — Length of the sliding window, it is the time interval between the first and the last condition. The unit of `window` depends on the `timestamp` itself and varies. Determined using the expression `timestamp of cond1 <= timestamp of cond2 <= ... <= timestamp of condN <= timestamp of cond1 + window`.
+-   `mode` — It is an optional argument. One or more modes can be set.
+    -   `'strict_deduplication'` — If the same condition holds for the sequence of events, then such repeating event interrupts further processing.
+    -   `'strict_order'` — Don't allow interventions of other events. E.g. in the case of `A->B->D->C`, it stops finding `A->B->C` at the `D` and the max event level is 2.
+    -   `'strict_increase'` — Apply conditions only to events with strictly increasing timestamps.
+
+**Returned value**
+
+The maximum number of consecutive triggered conditions from the chain within the sliding time window.
+All the chains in the selection are analyzed.
+
+Type: `Integer`.
+
+**Example**
+
+Determine if a set period of time is enough for the user to select a phone and purchase it twice in the online store.
+
+Set the following chain of events:
+
+1.  The user logged in to their account on the store (`eventID = 1003`).
+2.  The user searches for a phone (`eventID = 1007, product = 'phone'`).
+3.  The user placed an order (`eventID = 1009`).
+4.  The user made the order again (`eventID = 1010`).
+
+Input table:
+
+``` text
+┌─event_date─┬─user_id─┬───────────timestamp─┬─eventID─┬─product─┐
+│ 2019-01-28 │       1 │ 2019-01-29 10:00:00 │    1003 │ phone   │
+└────────────┴─────────┴─────────────────────┴─────────┴─────────┘
+┌─event_date─┬─user_id─┬───────────timestamp─┬─eventID─┬─product─┐
+│ 2019-01-31 │       1 │ 2019-01-31 09:00:00 │    1007 │ phone   │
+└────────────┴─────────┴─────────────────────┴─────────┴─────────┘
+┌─event_date─┬─user_id─┬───────────timestamp─┬─eventID─┬─product─┐
+│ 2019-01-30 │       1 │ 2019-01-30 08:00:00 │    1009 │ phone   │
+└────────────┴─────────┴─────────────────────┴─────────┴─────────┘
+┌─event_date─┬─user_id─┬───────────timestamp─┬─eventID─┬─product─┐
+│ 2019-02-01 │       1 │ 2019-02-01 08:00:00 │    1010 │ phone   │
+└────────────┴─────────┴─────────────────────┴─────────┴─────────┘
+```
+
+Find out how far the user `user_id` could get through the chain in a period in January-February of 2019.
+
+Query:
+
+``` sql
+SELECT
+    level,
+    count() AS c
+FROM
+(
+    SELECT
+        user_id,
+        windowFunnel(6048000000000000)(timestamp, eventID = 1003, eventID = 1009, eventID = 1007, eventID = 1010) AS level
+    FROM trend
+    WHERE (event_date >= '2019-01-01') AND (event_date <= '2019-02-02')
+    GROUP BY user_id
+)
+GROUP BY level
+ORDER BY level ASC;
+```
+
+Result:
+
+``` text
+┌─level─┬─c─┐
+│     4 │ 1 │
+└───────┴───┘
+```
+
+## retention {#retention}
+
+The function takes as arguments a set of conditions from 1 to 32 arguments of type `UInt8` that indicate whether a certain condition was met for the event.
+Any condition can be specified as an argument (as in [WHERE](../../sql-reference/statements/select/where.md#select-where)).
+
+The conditions, except the first, apply in pairs: the result of the second will be true if the first and second are true, of the third if the first and third are true, etc.
+
+**Syntax**
+
+``` sql
+retention(cond1, cond2, ..., cond32);
+```
+
+**Arguments**
+
+-   `cond` — An expression that returns a `UInt8` result (1 or 0).
+
+**Returned value**
+
+The array of 1 or 0.
+
+-   1 — Condition was met for the event.
+-   0 — Condition wasn’t met for the event.
+
+Type: `UInt8`.
+
+**Example**
+
+Let’s consider an example of calculating the `retention` function to determine site traffic.
+
+**1.** Сreate a table to illustrate an example.
+
+``` sql
+CREATE TABLE retention_test(date Date, uid Int32) ENGINE = Memory;
+
+INSERT INTO retention_test SELECT '2020-01-01', number FROM numbers(5);
+INSERT INTO retention_test SELECT '2020-01-02', number FROM numbers(10);
+INSERT INTO retention_test SELECT '2020-01-03', number FROM numbers(15);
+```
+
+Input table:
+
+Query:
+
+``` sql
+SELECT * FROM retention_test
+```
+
+Result:
+
+``` text
+┌───────date─┬─uid─┐
+│ 2020-01-01 │   0 │
+│ 2020-01-01 │   1 │
+│ 2020-01-01 │   2 │
+│ 2020-01-01 │   3 │
+│ 2020-01-01 │   4 │
+└────────────┴─────┘
+┌───────date─┬─uid─┐
+│ 2020-01-02 │   0 │
+│ 2020-01-02 │   1 │
+│ 2020-01-02 │   2 │
+│ 2020-01-02 │   3 │
+│ 2020-01-02 │   4 │
+│ 2020-01-02 │   5 │
+│ 2020-01-02 │   6 │
+│ 2020-01-02 │   7 │
+│ 2020-01-02 │   8 │
+│ 2020-01-02 │   9 │
+└────────────┴─────┘
+┌───────date─┬─uid─┐
+│ 2020-01-03 │   0 │
+│ 2020-01-03 │   1 │
+│ 2020-01-03 │   2 │
+│ 2020-01-03 │   3 │
+│ 2020-01-03 │   4 │
+│ 2020-01-03 │   5 │
+│ 2020-01-03 │   6 │
+│ 2020-01-03 │   7 │
+│ 2020-01-03 │   8 │
+│ 2020-01-03 │   9 │
+│ 2020-01-03 │  10 │
+│ 2020-01-03 │  11 │
+│ 2020-01-03 │  12 │
+│ 2020-01-03 │  13 │
+│ 2020-01-03 │  14 │
+└────────────┴─────┘
+```
+
+**2.** Group users by unique ID `uid` using the `retention` function.
+
+Query:
+
+``` sql
+SELECT
+    uid,
+    retention(date = '2020-01-01', date = '2020-01-02', date = '2020-01-03') AS r
+FROM retention_test
+WHERE date IN ('2020-01-01', '2020-01-02', '2020-01-03')
+GROUP BY uid
+ORDER BY uid ASC
+```
+
+Result:
+
+``` text
+┌─uid─┬─r───────┐
+│   0 │ [1,1,1] │
+│   1 │ [1,1,1] │
+│   2 │ [1,1,1] │
+│   3 │ [1,1,1] │
+│   4 │ [1,1,1] │
+│   5 │ [0,0,0] │
+│   6 │ [0,0,0] │
+│   7 │ [0,0,0] │
+│   8 │ [0,0,0] │
+│   9 │ [0,0,0] │
+│  10 │ [0,0,0] │
+│  11 │ [0,0,0] │
+│  12 │ [0,0,0] │
+│  13 │ [0,0,0] │
+│  14 │ [0,0,0] │
+└─────┴─────────┘
+```
+
+**3.** Calculate the total number of site visits per day.
+
+Query:
+
+``` sql
+SELECT
+    sum(r[1]) AS r1,
+    sum(r[2]) AS r2,
+    sum(r[3]) AS r3
+FROM
+(
+    SELECT
+        uid,
+        retention(date = '2020-01-01', date = '2020-01-02', date = '2020-01-03') AS r
+    FROM retention_test
+    WHERE date IN ('2020-01-01', '2020-01-02', '2020-01-03')
+    GROUP BY uid
+)
+```
+
+Result:
+
+``` text
+┌─r1─┬─r2─┬─r3─┐
+│  5 │  5 │  5 │
+└────┴────┴────┘
+```
+
+Where:
+
+-   `r1`- the number of unique visitors who visited the site during 2020-01-01 (the `cond1` condition).
+-   `r2`- the number of unique visitors who visited the site during a specific time period between 2020-01-01 and 2020-01-02 (`cond1` and `cond2` conditions).
+-   `r3`- the number of unique visitors who visited the site during a specific time period between 2020-01-01 and 2020-01-03 (`cond1` and `cond3` conditions).
+
+## uniqUpTo(N)(x) {#uniquptonx}
+
+Calculates the number of different argument values ​​if it is less than or equal to N. If the number of different argument values is greater than N, it returns N + 1.
+
+Recommended for use with small Ns, up to 10. The maximum value of N is 100.
+
+For the state of an aggregate function, it uses the amount of memory equal to 1 + N \* the size of one value of bytes.
+For strings, it stores a non-cryptographic hash of 8 bytes. That is, the calculation is approximated for strings.
+
+The function also works for several arguments.
+
+It works as fast as possible, except for cases when a large N value is used and the number of unique values is slightly less than N.
+
+Usage example:
+
+``` text
+Problem: Generate a report that shows only keywords that produced at least 5 unique users.
+Solution: Write in the GROUP BY query SearchPhrase HAVING uniqUpTo(4)(UserID) >= 5
+```
+
+
+## sumMapFiltered(keys_to_keep)(keys, values) {#summapfilteredkeys-to-keepkeys-values}
+
+Same behavior as [sumMap](../../sql-reference/aggregate-functions/reference/summap.md#agg_functions-summap) except that an array of keys is passed as a parameter. This can be especially useful when working with a high cardinality of keys.
+
+## sequenceNextNode {#sequenceNextNode}
+
+Returns a value of the next event that matched an event chain.
+
+_Experimental function, `SET allow_experimental_funnel_functions = 1` to enable it._
+
+**Syntax**
+
+``` sql
+sequenceNextNode(direction, base)(timestamp, event_column, base_condition, event1, event2, event3, ...)
+```
+
+**Parameters**
+
+-   `direction` — Used to navigate to directions.
+    - forward — Moving forward.
+    - backward — Moving backward.
+
+-   `base` — Used to set the base point.
+    - head — Set the base point to the first event.
+    - tail — Set the base point to the last event.
+    - first_match — Set the base point to the first matched `event1`.
+    - last_match — Set the base point to the last matched `event1`.
+
+**Arguments**
+
+-   `timestamp` — Name of the column containing the timestamp. Data types supported: [Date](../../sql-reference/data-types/date.md), [DateTime](../../sql-reference/data-types/datetime.md#data_type-datetime) and other unsigned integer types.
+-   `event_column` — Name of the column containing the value of the next event to be returned. Data types supported: [String](../../sql-reference/data-types/string.md) and [Nullable(String)](../../sql-reference/data-types/nullable.md).
+-   `base_condition` — Condition that the base point must fulfill.
+-   `event1`, `event2`, ... — Conditions describing the chain of events. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-  `event_column[next_index]` — If the pattern is matched and next value exists.
+-  `NULL` - If the pattern isn’t matched or next value doesn't exist.
+
+Type: [Nullable(String)](../../sql-reference/data-types/nullable.md).
+
+**Example**
+
+It can be used when events are A->B->C->D->E and you want to know the event following B->C, which is D.
+
+The query statement searching the event following A->B:
+
+``` sql
+CREATE TABLE test_flow (
+    dt DateTime,
+    id int,
+    page String)
+ENGINE = MergeTree()
+PARTITION BY toYYYYMMDD(dt)
+ORDER BY id;
+
+INSERT INTO test_flow VALUES (1, 1, 'A') (2, 1, 'B') (3, 1, 'C') (4, 1, 'D') (5, 1, 'E');
+
+SELECT id, sequenceNextNode('forward', 'head')(dt, page, page = 'A', page = 'A', page = 'B') as next_flow FROM test_flow GROUP BY id;
+```
+
+Result:
+
+``` text
+┌─id─┬─next_flow─┐
+│  1 │ C         │
+└────┴───────────┘
+```
+
+**Behavior for `forward` and `head`**
+
+``` sql
+ALTER TABLE test_flow DELETE WHERE 1 = 1 settings mutations_sync = 1;
+
+INSERT INTO test_flow VALUES (1, 1, 'Home') (2, 1, 'Gift') (3, 1, 'Exit');
+INSERT INTO test_flow VALUES (1, 2, 'Home') (2, 2, 'Home') (3, 2, 'Gift') (4, 2, 'Basket');
+INSERT INTO test_flow VALUES (1, 3, 'Gift') (2, 3, 'Home') (3, 3, 'Gift') (4, 3, 'Basket');
+```
+
+``` sql
+SELECT id, sequenceNextNode('forward', 'head')(dt, page, page = 'Home', page = 'Home', page = 'Gift') FROM test_flow GROUP BY id;
+
+                  dt   id   page
+ 1970-01-01 09:00:01    1   Home // Base point, Matched with Home
+ 1970-01-01 09:00:02    1   Gift // Matched with Gift
+ 1970-01-01 09:00:03    1   Exit // The result
+
+ 1970-01-01 09:00:01    2   Home // Base point, Matched with Home
+ 1970-01-01 09:00:02    2   Home // Unmatched with Gift
+ 1970-01-01 09:00:03    2   Gift
+ 1970-01-01 09:00:04    2   Basket
+
+ 1970-01-01 09:00:01    3   Gift // Base point, Unmatched with Home
+ 1970-01-01 09:00:02    3   Home
+ 1970-01-01 09:00:03    3   Gift
+ 1970-01-01 09:00:04    3   Basket
+```
+
+**Behavior for `backward` and `tail`**
+
+``` sql
+SELECT id, sequenceNextNode('backward', 'tail')(dt, page, page = 'Basket', page = 'Basket', page = 'Gift') FROM test_flow GROUP BY id;
+
+                 dt   id   page
+1970-01-01 09:00:01    1   Home
+1970-01-01 09:00:02    1   Gift
+1970-01-01 09:00:03    1   Exit // Base point, Unmatched with Basket
+
+1970-01-01 09:00:01    2   Home
+1970-01-01 09:00:02    2   Home // The result
+1970-01-01 09:00:03    2   Gift // Matched with Gift
+1970-01-01 09:00:04    2   Basket // Base point, Matched with Basket
+
+1970-01-01 09:00:01    3   Gift
+1970-01-01 09:00:02    3   Home // The result
+1970-01-01 09:00:03    3   Gift // Base point, Matched with Gift
+1970-01-01 09:00:04    3   Basket // Base point, Matched with Basket
+```
+
+
+**Behavior for `forward` and `first_match`**
+
+``` sql
+SELECT id, sequenceNextNode('forward', 'first_match')(dt, page, page = 'Gift', page = 'Gift') FROM test_flow GROUP BY id;
+
+                 dt   id   page
+1970-01-01 09:00:01    1   Home
+1970-01-01 09:00:02    1   Gift // Base point
+1970-01-01 09:00:03    1   Exit // The result
+
+1970-01-01 09:00:01    2   Home
+1970-01-01 09:00:02    2   Home
+1970-01-01 09:00:03    2   Gift // Base point
+1970-01-01 09:00:04    2   Basket  The result
+
+1970-01-01 09:00:01    3   Gift // Base point
+1970-01-01 09:00:02    3   Home // The result
+1970-01-01 09:00:03    3   Gift
+1970-01-01 09:00:04    3   Basket
+```
+
+``` sql
+SELECT id, sequenceNextNode('forward', 'first_match')(dt, page, page = 'Gift', page = 'Gift', page = 'Home') FROM test_flow GROUP BY id;
+
+                 dt   id   page
+1970-01-01 09:00:01    1   Home
+1970-01-01 09:00:02    1   Gift // Base point
+1970-01-01 09:00:03    1   Exit // Unmatched with Home
+
+1970-01-01 09:00:01    2   Home
+1970-01-01 09:00:02    2   Home
+1970-01-01 09:00:03    2   Gift // Base point
+1970-01-01 09:00:04    2   Basket // Unmatched with Home
+
+1970-01-01 09:00:01    3   Gift // Base point
+1970-01-01 09:00:02    3   Home // Matched with Home
+1970-01-01 09:00:03    3   Gift // The result
+1970-01-01 09:00:04    3   Basket
+```
+
+
+**Behavior for `backward` and `last_match`**
+
+``` sql
+SELECT id, sequenceNextNode('backward', 'last_match')(dt, page, page = 'Gift', page = 'Gift') FROM test_flow GROUP BY id;
+
+                 dt   id   page
+1970-01-01 09:00:01    1   Home // The result
+1970-01-01 09:00:02    1   Gift // Base point
+1970-01-01 09:00:03    1   Exit
+
+1970-01-01 09:00:01    2   Home
+1970-01-01 09:00:02    2   Home // The result
+1970-01-01 09:00:03    2   Gift // Base point
+1970-01-01 09:00:04    2   Basket
+
+1970-01-01 09:00:01    3   Gift
+1970-01-01 09:00:02    3   Home // The result
+1970-01-01 09:00:03    3   Gift // Base point
+1970-01-01 09:00:04    3   Basket
+```
+
+``` sql
+SELECT id, sequenceNextNode('backward', 'last_match')(dt, page, page = 'Gift', page = 'Gift', page = 'Home') FROM test_flow GROUP BY id;
+
+                 dt   id   page
+1970-01-01 09:00:01    1   Home // Matched with Home, the result is null
+1970-01-01 09:00:02    1   Gift // Base point
+1970-01-01 09:00:03    1   Exit
+
+1970-01-01 09:00:01    2   Home // The result
+1970-01-01 09:00:02    2   Home // Matched with Home
+1970-01-01 09:00:03    2   Gift // Base point
+1970-01-01 09:00:04    2   Basket
+
+1970-01-01 09:00:01    3   Gift // The result
+1970-01-01 09:00:02    3   Home // Matched with Home
+1970-01-01 09:00:03    3   Gift // Base point
+1970-01-01 09:00:04    3   Basket
+```
+
+
+**Behavior for `base_condition`**
+
+``` sql
+CREATE TABLE test_flow_basecond
+(
+    `dt` DateTime,
+    `id` int,
+    `page` String,
+    `ref` String
+)
+ENGINE = MergeTree
+PARTITION BY toYYYYMMDD(dt)
+ORDER BY id;
+
+INSERT INTO test_flow_basecond VALUES (1, 1, 'A', 'ref4') (2, 1, 'A', 'ref3') (3, 1, 'B', 'ref2') (4, 1, 'B', 'ref1');
+```
+
+``` sql
+SELECT id, sequenceNextNode('forward', 'head')(dt, page, ref = 'ref1', page = 'A') FROM test_flow_basecond GROUP BY id;
+
+                  dt   id   page   ref
+ 1970-01-01 09:00:01    1   A      ref4 // The head can not be base point because the ref column of the head unmatched with 'ref1'.
+ 1970-01-01 09:00:02    1   A      ref3
+ 1970-01-01 09:00:03    1   B      ref2
+ 1970-01-01 09:00:04    1   B      ref1
+ ```
+
+``` sql
+SELECT id, sequenceNextNode('backward', 'tail')(dt, page, ref = 'ref4', page = 'B') FROM test_flow_basecond GROUP BY id;
+
+                  dt   id   page   ref
+ 1970-01-01 09:00:01    1   A      ref4
+ 1970-01-01 09:00:02    1   A      ref3
+ 1970-01-01 09:00:03    1   B      ref2
+ 1970-01-01 09:00:04    1   B      ref1 // The tail can not be base point because the ref column of the tail unmatched with 'ref4'.
+```
+
+``` sql
+SELECT id, sequenceNextNode('forward', 'first_match')(dt, page, ref = 'ref3', page = 'A') FROM test_flow_basecond GROUP BY id;
+
+                  dt   id   page   ref
+ 1970-01-01 09:00:01    1   A      ref4 // This row can not be base point because the ref column unmatched with 'ref3'.
+ 1970-01-01 09:00:02    1   A      ref3 // Base point
+ 1970-01-01 09:00:03    1   B      ref2 // The result
+ 1970-01-01 09:00:04    1   B      ref1
+```
+
+``` sql
+SELECT id, sequenceNextNode('backward', 'last_match')(dt, page, ref = 'ref2', page = 'B') FROM test_flow_basecond GROUP BY id;
+
+                  dt   id   page   ref
+ 1970-01-01 09:00:01    1   A      ref4
+ 1970-01-01 09:00:02    1   A      ref3 // The result
+ 1970-01-01 09:00:03    1   B      ref2 // Base point
+ 1970-01-01 09:00:04    1   B      ref1 // This row can not be base point because the ref column unmatched with 'ref2'.
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/any.md b/docs/en/reference/sql-reference/aggregate-functions/reference/any.md
new file mode 100644
index 00000000000..3b5539c5b8d
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/any.md
@@ -0,0 +1,13 @@
+---
+sidebar_position: 6
+---
+
+# any {#agg_function-any}
+
+Selects the first encountered value.
+The query can be executed in any order and even in a different order each time, so the result of this function is indeterminate.
+To get a determinate result, you can use the ‘min’ or ‘max’ function instead of ‘any’.
+
+In some cases, you can rely on the order of execution. This applies to cases when SELECT comes from a subquery that uses ORDER BY.
+
+When a `SELECT` query has the `GROUP BY` clause or at least one aggregate function, ClickHouse (in contrast to MySQL) requires that all expressions in the `SELECT`, `HAVING`, and `ORDER BY` clauses be calculated from keys or from aggregate functions. In other words, each column selected from the table must be used either in keys or inside aggregate functions. To get behavior like in MySQL, you can put the other columns in the `any` aggregate function.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/anyheavy.md b/docs/en/reference/sql-reference/aggregate-functions/reference/anyheavy.md
new file mode 100644
index 00000000000..29144ee2f50
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/anyheavy.md
@@ -0,0 +1,30 @@
+---
+sidebar_position: 103
+---
+
+# anyHeavy {#anyheavyx}
+
+Selects a frequently occurring value using the [heavy hitters](http://www.cs.umd.edu/~samir/498/karp.pdf) algorithm. If there is a value that occurs more than in half the cases in each of the query’s execution threads, this value is returned. Normally, the result is nondeterministic.
+
+``` sql
+anyHeavy(column)
+```
+
+**Arguments**
+
+-   `column` – The column name.
+
+**Example**
+
+Take the [OnTime](../../../example-datasets/ontime.md) data set and select any frequently occurring value in the `AirlineID` column.
+
+``` sql
+SELECT anyHeavy(AirlineID) AS res
+FROM ontime
+```
+
+``` text
+┌───res─┐
+│ 19690 │
+└───────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/anylast.md b/docs/en/reference/sql-reference/aggregate-functions/reference/anylast.md
new file mode 100644
index 00000000000..2a01a587f70
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/anylast.md
@@ -0,0 +1,8 @@
+---
+sidebar_position: 104
+---
+
+## anyLast {#anylastx}
+
+Selects the last value encountered.
+The result is just as indeterminate as for the [any](../../../sql-reference/aggregate-functions/reference/any.md) function.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/argmax.md b/docs/en/reference/sql-reference/aggregate-functions/reference/argmax.md
new file mode 100644
index 00000000000..f09bcd0bba2
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/argmax.md
@@ -0,0 +1,50 @@
+---
+sidebar_position: 106
+---
+
+# argMax {#agg-function-argmax}
+
+Calculates the `arg` value for a maximum `val` value. If there are several different values of `arg` for maximum values of `val`, returns the first of these values encountered.
+
+**Syntax**
+
+``` sql
+argMax(arg, val)
+```
+
+**Arguments**
+
+-   `arg` — Argument.
+-   `val` — Value.
+
+**Returned value**
+
+-   `arg` value that corresponds to maximum `val` value.
+
+Type: matches `arg` type.
+
+**Example**
+
+Input table:
+
+``` text
+┌─user─────┬─salary─┐
+│ director │   5000 │
+│ manager  │   3000 │
+│ worker   │   1000 │
+└──────────┴────────┘
+```
+
+Query:
+
+``` sql
+SELECT argMax(user, salary) FROM salary;
+```
+
+Result:
+
+``` text
+┌─argMax(user, salary)─┐
+│ director             │
+└──────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/argmin.md b/docs/en/reference/sql-reference/aggregate-functions/reference/argmin.md
new file mode 100644
index 00000000000..926fda5a512
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/argmin.md
@@ -0,0 +1,50 @@
+---
+sidebar_position: 105
+---
+
+# argMin {#agg-function-argmin}
+
+Calculates the `arg` value for a minimum `val` value. If there are several different values of `arg` for minimum values of `val`, returns the first of these values encountered.
+
+**Syntax**
+
+``` sql
+argMin(arg, val)
+```
+
+**Arguments**
+
+-   `arg` — Argument.
+-   `val` — Value.
+
+**Returned value**
+
+-   `arg` value that corresponds to minimum `val` value.
+
+Type: matches `arg` type.
+
+**Example**
+
+Input table:
+
+``` text
+┌─user─────┬─salary─┐
+│ director │   5000 │
+│ manager  │   3000 │
+│ worker   │   1000 │
+└──────────┴────────┘
+```
+
+Query:
+
+``` sql
+SELECT argMin(user, salary) FROM salary
+```
+
+Result:
+
+``` text
+┌─argMin(user, salary)─┐
+│ worker               │
+└──────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/avg.md b/docs/en/reference/sql-reference/aggregate-functions/reference/avg.md
new file mode 100644
index 00000000000..b7b5e9fbed4
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/avg.md
@@ -0,0 +1,66 @@
+---
+sidebar_position: 5
+---
+
+# avg {#agg_function-avg}
+
+Calculates the arithmetic mean.
+
+**Syntax**
+
+``` sql
+avg(x)
+```
+
+**Arguments**
+
+-   `x` — input values, must be [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md), or [Decimal](../../../sql-reference/data-types/decimal.md).
+
+**Returned value**
+
+-   The arithmetic mean, always as [Float64](../../../sql-reference/data-types/float.md).
+-   `NaN` if the input parameter `x` is empty.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT avg(x) FROM values('x Int8', 0, 1, 2, 3, 4, 5);
+```
+
+Result:
+
+``` text
+┌─avg(x)─┐
+│    2.5 │
+└────────┘
+```
+
+**Example**
+
+Create a temp table:
+
+Query:
+
+``` sql
+CREATE table test (t UInt8) ENGINE = Memory;
+```
+
+Get the arithmetic mean:
+
+Query:
+
+```
+SELECT avg(t) FROM test;
+```
+
+Result:
+
+``` text
+┌─avg(x)─┐
+│    nan │
+└────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/aggregate-functions/reference/avg/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/avgweighted.md b/docs/en/reference/sql-reference/aggregate-functions/reference/avgweighted.md
new file mode 100644
index 00000000000..126c0c2f1d7
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/avgweighted.md
@@ -0,0 +1,99 @@
+---
+sidebar_position: 107
+---
+
+# avgWeighted {#avgweighted}
+
+Calculates the [weighted arithmetic mean](https://en.wikipedia.org/wiki/Weighted_arithmetic_mean).
+
+**Syntax**
+
+``` sql
+avgWeighted(x, weight)
+```
+
+**Arguments**
+
+-   `x` — Values.
+-   `weight` — Weights of the values.
+
+`x` and `weight` must both be
+[Integer](../../../sql-reference/data-types/int-uint.md),
+[floating-point](../../../sql-reference/data-types/float.md), or
+[Decimal](../../../sql-reference/data-types/decimal.md),
+but may have different types.
+
+**Returned value**
+
+-   `NaN` if all the weights are equal to 0 or the supplied weights parameter is empty.
+-   Weighted mean otherwise.
+
+**Return type** is always [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT avgWeighted(x, w)
+FROM values('x Int8, w Int8', (4, 1), (1, 0), (10, 2))
+```
+
+Result:
+
+``` text
+┌─avgWeighted(x, weight)─┐
+│                      8 │
+└────────────────────────┘
+```
+
+**Example**
+
+Query:
+
+``` sql
+SELECT avgWeighted(x, w)
+FROM values('x Int8, w Float64', (4, 1), (1, 0), (10, 2))
+```
+
+Result:
+
+``` text
+┌─avgWeighted(x, weight)─┐
+│                      8 │
+└────────────────────────┘
+```
+
+**Example**
+
+Query:
+
+``` sql
+SELECT avgWeighted(x, w)
+FROM values('x Int8, w Int8', (0, 0), (1, 0), (10, 0))
+```
+
+Result:
+
+``` text
+┌─avgWeighted(x, weight)─┐
+│                    nan │
+└────────────────────────┘
+```
+
+**Example**
+
+Query:
+
+``` sql
+CREATE table test (t UInt8) ENGINE = Memory;
+SELECT avgWeighted(t) FROM test
+```
+
+Result:
+
+``` text
+┌─avgWeighted(x, weight)─┐
+│                    nan │
+└────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/categoricalinformationvalue.md b/docs/en/reference/sql-reference/aggregate-functions/reference/categoricalinformationvalue.md
new file mode 100644
index 00000000000..e836dbe868a
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/categoricalinformationvalue.md
@@ -0,0 +1,13 @@
+---
+sidebar_position: 250
+---
+
+# categoricalInformationValue {#categoricalinformationvalue}
+
+Calculates the value of `(P(tag = 1) - P(tag = 0))(log(P(tag = 1)) - log(P(tag = 0)))` for each category.
+
+``` sql
+categoricalInformationValue(category1, category2, ..., tag)
+```
+
+The result indicates how a discrete (categorical) feature `[category1, category2, ...]` contribute to a learning model which predicting the value of `tag`.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/corr.md b/docs/en/reference/sql-reference/aggregate-functions/reference/corr.md
new file mode 100644
index 00000000000..c6d7fd5baed
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/corr.md
@@ -0,0 +1,13 @@
+---
+sidebar_position: 107
+---
+
+# corr {#corrx-y}
+
+Syntax: `corr(x, y)`
+
+Calculates the Pearson correlation coefficient: `Σ((x - x̅)(y - y̅)) / sqrt(Σ((x - x̅)^2) * Σ((y - y̅)^2))`.
+
+:::note    
+This function uses a numerically unstable algorithm. If you need [numerical stability](https://en.wikipedia.org/wiki/Numerical_stability) in calculations, use the `corrStable` function. It works slower but provides a lower computational error.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/count.md b/docs/en/reference/sql-reference/aggregate-functions/reference/count.md
new file mode 100644
index 00000000000..8df4aef9d03
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/count.md
@@ -0,0 +1,72 @@
+---
+sidebar_position: 1
+---
+
+# count {#agg_function-count}
+
+Counts the number of rows or not-NULL values.
+
+ClickHouse supports the following syntaxes for `count`:
+
+-   `count(expr)` or `COUNT(DISTINCT expr)`.
+-   `count()` or `COUNT(*)`. The `count()` syntax is ClickHouse-specific.
+
+**Arguments**
+
+The function can take:
+
+-   Zero parameters.
+-   One [expression](../../../sql-reference/syntax.md#syntax-expressions).
+
+**Returned value**
+
+-   If the function is called without parameters it counts the number of rows.
+-   If the [expression](../../../sql-reference/syntax.md#syntax-expressions) is passed, then the function counts how many times this expression returned not null. If the expression returns a [Nullable](../../../sql-reference/data-types/nullable.md)-type value, then the result of `count` stays not `Nullable`. The function returns 0 if the expression returned `NULL` for all the rows.
+
+In both cases the type of the returned value is [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Details**
+
+ClickHouse supports the `COUNT(DISTINCT ...)` syntax. The behavior of this construction depends on the [count_distinct_implementation](../../../operations/settings/settings.md#settings-count_distinct_implementation) setting. It defines which of the [uniq\*](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq) functions is used to perform the operation. The default is the [uniqExact](../../../sql-reference/aggregate-functions/reference/uniqexact.md#agg_function-uniqexact) function.
+
+The `SELECT count() FROM table` query is optimized by default using metadata from MergeTree. If you need to use row-level security, disable optimization using the [optimize_trivial_count_query](../../../operations/settings/settings.md#optimize-trivial-count-query) setting.
+
+However `SELECT count(nullable_column) FROM table` query can be optimized by enabling the [optimize_functions_to_subcolumns](../../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [null](../../../sql-reference/data-types/nullable.md#finding-null) subcolumn instead of reading and processing the whole column data. The query `SELECT count(n) FROM table` transforms to `SELECT sum(NOT n.null) FROM table`.
+
+**Examples**
+
+Example 1:
+
+``` sql
+SELECT count() FROM t
+```
+
+``` text
+┌─count()─┐
+│       5 │
+└─────────┘
+```
+
+Example 2:
+
+``` sql
+SELECT name, value FROM system.settings WHERE name = 'count_distinct_implementation'
+```
+
+``` text
+┌─name──────────────────────────┬─value─────┐
+│ count_distinct_implementation │ uniqExact │
+└───────────────────────────────┴───────────┘
+```
+
+``` sql
+SELECT count(DISTINCT num) FROM t
+```
+
+``` text
+┌─uniqExact(num)─┐
+│              3 │
+└────────────────┘
+```
+
+This example shows that `count(DISTINCT num)` is performed by the `uniqExact` function according to the `count_distinct_implementation` setting value.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/covarpop.md b/docs/en/reference/sql-reference/aggregate-functions/reference/covarpop.md
new file mode 100644
index 00000000000..363a98c3f16
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/covarpop.md
@@ -0,0 +1,13 @@
+---
+sidebar_position: 36
+---
+
+# covarPop {#covarpop}
+
+Syntax: `covarPop(x, y)`
+
+Calculates the value of `Σ((x - x̅)(y - y̅)) / n`.
+
+:::note    
+This function uses a numerically unstable algorithm. If you need [numerical stability](https://en.wikipedia.org/wiki/Numerical_stability) in calculations, use the `covarPopStable` function. It works slower but provides a lower computational error.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/covarsamp.md b/docs/en/reference/sql-reference/aggregate-functions/reference/covarsamp.md
new file mode 100644
index 00000000000..977b3f3b5b4
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/covarsamp.md
@@ -0,0 +1,13 @@
+---
+sidebar_position: 37
+---
+
+# covarSamp {#covarsamp}
+
+Calculates the value of `Σ((x - x̅)(y - y̅)) / (n - 1)`.
+
+Returns Float64. When `n <= 1`, returns +∞.
+
+:::note    
+This function uses a numerically unstable algorithm. If you need [numerical stability](https://en.wikipedia.org/wiki/Numerical_stability) in calculations, use the `covarSampStable` function. It works slower but provides a lower computational error.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/deltasum.md b/docs/en/reference/sql-reference/aggregate-functions/reference/deltasum.md
new file mode 100644
index 00000000000..ac35938e26d
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/deltasum.md
@@ -0,0 +1,73 @@
+---
+sidebar_position: 141
+---
+
+# deltaSum {#agg_functions-deltasum}
+
+Sums the arithmetic difference between consecutive rows. If the difference is negative, it is ignored.
+
+:::note    
+The underlying data must be sorted for this function to work properly. If you would like to use this function in a [materialized view](../../../sql-reference/statements/create/view.md#materialized), you most likely want to use the [deltaSumTimestamp](../../../sql-reference/aggregate-functions/reference/deltasumtimestamp.md#agg_functions-deltasumtimestamp) method instead.
+:::
+
+**Syntax**
+
+``` sql
+deltaSum(value)
+```
+
+**Arguments**
+
+-   `value` — Input values, must be [Integer](../../data-types/int-uint.md) or [Float](../../data-types/float.md) type.
+
+**Returned value**
+
+- A gained arithmetic difference of the `Integer` or `Float` type.
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT deltaSum(arrayJoin([1, 2, 3]));
+```
+
+Result:
+
+``` text
+┌─deltaSum(arrayJoin([1, 2, 3]))─┐
+│                              2 │
+└────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT deltaSum(arrayJoin([1, 2, 3, 0, 3, 4, 2, 3]));
+```
+
+Result:
+
+``` text
+┌─deltaSum(arrayJoin([1, 2, 3, 0, 3, 4, 2, 3]))─┐
+│                                             7 │
+└───────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT deltaSum(arrayJoin([2.25, 3, 4.5]));
+```
+
+Result:
+
+``` text
+┌─deltaSum(arrayJoin([2.25, 3, 4.5]))─┐
+│                                2.25 │
+└─────────────────────────────────────┘
+```
+
+## See Also {#see-also}
+
+-   [runningDifference](../../functions/other-functions.md#other_functions-runningdifference)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/deltasumtimestamp.md b/docs/en/reference/sql-reference/aggregate-functions/reference/deltasumtimestamp.md
new file mode 100644
index 00000000000..e1024e58328
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/deltasumtimestamp.md
@@ -0,0 +1,45 @@
+---
+sidebar_position: 141
+---
+
+# deltaSumTimestamp {#agg_functions-deltasumtimestamp}
+
+Adds the difference between consecutive rows. If the difference is negative, it is ignored.
+
+This function is primarily for [materialized views](../../../sql-reference/statements/create/view.md#materialized) that are ordered by some time bucket-aligned timestamp, for example, a `toStartOfMinute` bucket. Because the rows in such a materialized view will all have the same timestamp, it is impossible for them to be merged in the "right" order. This function keeps track of the `timestamp` of the values it's seen, so it's possible to order the states correctly during merging.
+
+To calculate the delta sum across an ordered collection you can simply use the [deltaSum](../../../sql-reference/aggregate-functions/reference/deltasum.md#agg_functions-deltasum) function.
+
+**Syntax**
+
+``` sql
+deltaSumTimestamp(value, timestamp)
+```
+
+**Arguments**
+
+-   `value` — Input values, must be some [Integer](../../data-types/int-uint.md) type or [Float](../../data-types/float.md) type or a [Date](../../data-types/date.md) or [DateTime](../../data-types/datetime.md).
+-   `timestamp` — The parameter for order values, must be some [Integer](../../data-types/int-uint.md) type or [Float](../../data-types/float.md) type or a [Date](../../data-types/date.md) or [DateTime](../../data-types/datetime.md).
+
+**Returned value**
+
+-   Accumulated differences between consecutive values, ordered by the `timestamp` parameter.
+
+Type: [Integer](../../data-types/int-uint.md) or [Float](../../data-types/float.md) or [Date](../../data-types/date.md) or [DateTime](../../data-types/datetime.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT deltaSumTimestamp(value, timestamp)
+FROM (SELECT number AS timestamp, [0, 4, 8, 3, 0, 0, 0, 1, 3, 5][number] AS value FROM numbers(1, 10));
+```
+
+Result:
+
+``` text
+┌─deltaSumTimestamp(value, timestamp)─┐
+│                                  13 │
+└─────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/entropy.md b/docs/en/reference/sql-reference/aggregate-functions/reference/entropy.md
new file mode 100644
index 00000000000..9f1576c3ed8
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/entropy.md
@@ -0,0 +1,43 @@
+---
+sidebar_position: 302
+---
+
+# entropy {#entropy}
+
+Calculates [Shannon entropy](https://en.wikipedia.org/wiki/Entropy_(information_theory)) of a column of values.
+
+**Syntax**
+
+``` sql
+entropy(val)
+```
+
+**Arguments**
+
+-   `val` — Column of values of any type.
+
+**Returned value**
+
+-   Shannon entropy.
+
+Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE entropy (`vals` UInt32,`strings` String) ENGINE = Memory;
+
+INSERT INTO entropy VALUES (1, 'A'), (1, 'A'), (1,'A'), (1,'A'), (2,'B'), (2,'B'), (2,'C'), (2,'D');
+
+SELECT entropy(vals), entropy(strings) FROM entropy;
+```
+
+Result:
+
+``` text
+┌─entropy(vals)─┬─entropy(strings)─┐
+│             1 │             1.75 │
+└───────────────┴──────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/exponentialmovingaverage.md b/docs/en/reference/sql-reference/aggregate-functions/reference/exponentialmovingaverage.md
new file mode 100644
index 00000000000..2337a0c8dab
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/exponentialmovingaverage.md
@@ -0,0 +1,148 @@
+---
+sidebar_position: 108
+---
+
+## exponentialMovingAverage {#exponential-moving-average}
+
+Сalculates the exponential moving average of values for the determined time. 
+
+**Syntax**
+
+```sql
+exponentialMovingAverage(x)(value, timestamp)
+```
+
+Each `value` corresponds to the determinate `timestamp`. The half-life `x` is the time lag at which the exponential weights decay by one-half. The function returns a weighted average: the older the time point, the less weight the corresponding value is considered to be.
+
+**Arguments**
+
+-   `value` — Value. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
+-   `timestamp` — Timestamp. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
+
+**Parameters**
+
+-   `x` — Half-life period. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
+
+**Returned values**
+
+- Returnes an [exponentially smoothed moving average](https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average) of the values for the past `x` time at the latest point of time.
+
+Type: [Float64](../../../sql-reference/data-types/float.md#float32-float64).
+
+**Examples**
+
+Input table:
+
+``` text
+┌──temperature─┬─timestamp──┐
+│          95  │         1  │
+│          95  │         2  │
+│          95  │         3  │
+│          96  │         4  │
+│          96  │         5  │
+│          96  │         6  │
+│          96  │         7  │
+│          97  │         8  │
+│          97  │         9  │
+│          97  │        10  │
+│          97  │        11  │
+│          98  │        12  │
+│          98  │        13  │
+│          98  │        14  │
+│          98  │        15  │
+│          99  │        16  │
+│          99  │        17  │
+│          99  │        18  │
+│         100  │        19  │
+│         100  │        20  │
+└──────────────┴────────────┘
+```
+
+Query: 
+
+```sql
+SELECT exponentialMovingAverage(5)(temperature, timestamp);
+```
+
+Result:
+
+``` text
+┌──exponentialMovingAverage(5)(temperature, timestamp)──┐
+│                                    92.25779635374204  │
+└───────────────────────────────────────────────────────┘
+```
+
+Query: 
+
+```sql
+SELECT
+    value,
+    time,
+    round(exp_smooth, 3),
+    bar(exp_smooth, 0, 1, 50) AS bar
+FROM
+(
+    SELECT
+        (number = 0) OR (number >= 25) AS value,
+        number AS time,
+        exponentialMovingAverage(10)(value, time) OVER (Rows BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS exp_smooth
+    FROM numbers(50)
+)
+```
+
+Result:
+
+``` text
+┌─value─┬─time─┬─round(exp_smooth, 3)─┬─bar────────────────────────────────────────┐
+│     1 │    0 │                0.067 │ ███▎                                      │
+│     0 │    1 │                0.062 │ ███                                        │
+│     0 │    2 │                0.058 │ ██▊                                       │
+│     0 │    3 │                0.054 │ ██▋                                       │
+│     0 │    4 │                0.051 │ ██▌                                        │
+│     0 │    5 │                0.047 │ ██▎                                       │
+│     0 │    6 │                0.044 │ ██▏                                       │
+│     0 │    7 │                0.041 │ ██                                         │
+│     0 │    8 │                0.038 │ █▊                                        │
+│     0 │    9 │                0.036 │ █▋                                        │
+│     0 │   10 │                0.033 │ █▋                                        │
+│     0 │   11 │                0.031 │ █▌                                         │
+│     0 │   12 │                0.029 │ █▍                                        │
+│     0 │   13 │                0.027 │ █▎                                        │
+│     0 │   14 │                0.025 │ █▎                                        │
+│     0 │   15 │                0.024 │ █▏                                        │
+│     0 │   16 │                0.022 │ █                                          │
+│     0 │   17 │                0.021 │ █                                          │
+│     0 │   18 │                0.019 │ ▊                                         │
+│     0 │   19 │                0.018 │ ▊                                         │
+│     0 │   20 │                0.017 │ ▋                                         │
+│     0 │   21 │                0.016 │ ▋                                         │
+│     0 │   22 │                0.015 │ ▋                                         │
+│     0 │   23 │                0.014 │ ▋                                         │
+│     0 │   24 │                0.013 │ ▋                                         │
+│     1 │   25 │                0.079 │ ███▊                                      │
+│     1 │   26 │                 0.14 │ ███████                                    │
+│     1 │   27 │                0.198 │ █████████▊                                │
+│     1 │   28 │                0.252 │ ████████████▌                              │
+│     1 │   29 │                0.302 │ ███████████████                            │
+│     1 │   30 │                0.349 │ █████████████████▍                        │
+│     1 │   31 │                0.392 │ ███████████████████▌                       │
+│     1 │   32 │                0.433 │ █████████████████████▋                    │
+│     1 │   33 │                0.471 │ ███████████████████████▌                   │
+│     1 │   34 │                0.506 │ █████████████████████████▎                │
+│     1 │   35 │                0.539 │ ██████████████████████████▊               │
+│     1 │   36 │                 0.57 │ ████████████████████████████▌              │
+│     1 │   37 │                0.599 │ █████████████████████████████▊            │
+│     1 │   38 │                0.626 │ ███████████████████████████████▎          │
+│     1 │   39 │                0.651 │ ████████████████████████████████▌          │
+│     1 │   40 │                0.674 │ █████████████████████████████████▋        │
+│     1 │   41 │                0.696 │ ██████████████████████████████████▋       │
+│     1 │   42 │                0.716 │ ███████████████████████████████████▋      │
+│     1 │   43 │                0.735 │ ████████████████████████████████████▋     │
+│     1 │   44 │                0.753 │ █████████████████████████████████████▋    │
+│     1 │   45 │                 0.77 │ ██████████████████████████████████████▍   │
+│     1 │   46 │                0.785 │ ███████████████████████████████████████▎  │
+│     1 │   47 │                  0.8 │ ███████████████████████████████████████▊  │
+│     1 │   48 │                0.813 │ ████████████████████████████████████████▋ │
+│     1 │   49 │                0.825 │ █████████████████████████████████████████▎│
+└───────┴──────┴──────────────────────┴────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/grouparray.md b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparray.md
new file mode 100644
index 00000000000..348ac98c75b
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparray.md
@@ -0,0 +1,14 @@
+---
+sidebar_position: 110
+---
+
+# groupArray {#agg_function-grouparray}
+
+Syntax: `groupArray(x)` or `groupArray(max_size)(x)`
+
+Creates an array of argument values.
+Values can be added to the array in any (indeterminate) order.
+
+The second version (with the `max_size` parameter) limits the size of the resulting array to `max_size` elements. For example, `groupArray(1)(x)` is equivalent to `[any (x)]`.
+
+In some cases, you can still rely on the order of execution. This applies to cases when `SELECT` comes from a subquery that uses `ORDER BY`.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/grouparrayinsertat.md b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparrayinsertat.md
new file mode 100644
index 00000000000..0699326725e
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparrayinsertat.md
@@ -0,0 +1,91 @@
+---
+sidebar_position: 112
+---
+
+# groupArrayInsertAt {#grouparrayinsertat}
+
+Inserts a value into the array at the specified position.
+
+**Syntax**
+
+``` sql
+groupArrayInsertAt(default_x, size)(x, pos)
+```
+
+If in one query several values are inserted into the same position, the function behaves in the following ways:
+
+-   If a query is executed in a single thread, the first one of the inserted values is used.
+-   If a query is executed in multiple threads, the resulting value is an undetermined one of the inserted values.
+
+**Arguments**
+
+-   `x` — Value to be inserted. [Expression](../../../sql-reference/syntax.md#syntax-expressions) resulting in one of the [supported data types](../../../sql-reference/data-types/index.md).
+-   `pos` — Position at which the specified element `x` is to be inserted. Index numbering in the array starts from zero. [UInt32](../../../sql-reference/data-types/int-uint.md#uint-ranges).
+-   `default_x` — Default value for substituting in empty positions. Optional parameter. [Expression](../../../sql-reference/syntax.md#syntax-expressions) resulting in the data type configured for the `x` parameter. If `default_x` is not defined, the [default values](../../../sql-reference/statements/create/table.md#create-default-values) are used.
+-   `size` — Length of the resulting array. Optional parameter. When using this parameter, the default value `default_x` must be specified. [UInt32](../../../sql-reference/data-types/int-uint.md#uint-ranges).
+
+**Returned value**
+
+-   Array with inserted values.
+
+Type: [Array](../../../sql-reference/data-types/array.md#data-type-array).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT groupArrayInsertAt(toString(number), number * 2) FROM numbers(5);
+```
+
+Result:
+
+``` text
+┌─groupArrayInsertAt(toString(number), multiply(number, 2))─┐
+│ ['0','','1','','2','','3','','4']                         │
+└───────────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT groupArrayInsertAt('-')(toString(number), number * 2) FROM numbers(5);
+```
+
+Result:
+
+``` text
+┌─groupArrayInsertAt('-')(toString(number), multiply(number, 2))─┐
+│ ['0','-','1','-','2','-','3','-','4']                          │
+└────────────────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT groupArrayInsertAt('-', 5)(toString(number), number * 2) FROM numbers(5);
+```
+
+Result:
+
+``` text
+┌─groupArrayInsertAt('-', 5)(toString(number), multiply(number, 2))─┐
+│ ['0','-','1','-','2']                                             │
+└───────────────────────────────────────────────────────────────────┘
+```
+
+Multi-threaded insertion of elements into one position.
+
+Query:
+
+``` sql
+SELECT groupArrayInsertAt(number, 0) FROM numbers_mt(10) SETTINGS max_block_size = 1;
+```
+
+As a result of this query you get random integer in the `[0,9]` range. For example:
+
+``` text
+┌─groupArrayInsertAt(number, 0)─┐
+│ [7]                           │
+└───────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraymovingavg.md b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraymovingavg.md
new file mode 100644
index 00000000000..dc3cc74721e
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraymovingavg.md
@@ -0,0 +1,78 @@
+---
+sidebar_position: 114
+---
+
+# groupArrayMovingAvg {#agg_function-grouparraymovingavg}
+
+Calculates the moving average of input values.
+
+``` sql
+groupArrayMovingAvg(numbers_for_summing)
+groupArrayMovingAvg(window_size)(numbers_for_summing)
+```
+
+The function can take the window size as a parameter. If left unspecified, the function takes the window size equal to the number of rows in the column.
+
+**Arguments**
+
+-   `numbers_for_summing` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) resulting in a numeric data type value.
+-   `window_size` — Size of the calculation window.
+
+**Returned values**
+
+-   Array of the same size and type as the input data.
+
+The function uses [rounding towards zero](https://en.wikipedia.org/wiki/Rounding#Rounding_towards_zero). It truncates the decimal places insignificant for the resulting data type.
+
+**Example**
+
+The sample table `b`:
+
+``` sql
+CREATE TABLE t
+(
+    `int` UInt8,
+    `float` Float32,
+    `dec` Decimal32(2)
+)
+ENGINE = TinyLog
+```
+
+``` text
+┌─int─┬─float─┬──dec─┐
+│   1 │   1.1 │ 1.10 │
+│   2 │   2.2 │ 2.20 │
+│   4 │   4.4 │ 4.40 │
+│   7 │  7.77 │ 7.77 │
+└─────┴───────┴──────┘
+```
+
+The queries:
+
+``` sql
+SELECT
+    groupArrayMovingAvg(int) AS I,
+    groupArrayMovingAvg(float) AS F,
+    groupArrayMovingAvg(dec) AS D
+FROM t
+```
+
+``` text
+┌─I─────────┬─F───────────────────────────────────┬─D─────────────────────┐
+│ [0,0,1,3] │ [0.275,0.82500005,1.9250001,3.8675] │ [0.27,0.82,1.92,3.86] │
+└───────────┴─────────────────────────────────────┴───────────────────────┘
+```
+
+``` sql
+SELECT
+    groupArrayMovingAvg(2)(int) AS I,
+    groupArrayMovingAvg(2)(float) AS F,
+    groupArrayMovingAvg(2)(dec) AS D
+FROM t
+```
+
+``` text
+┌─I─────────┬─F────────────────────────────────┬─D─────────────────────┐
+│ [0,1,3,5] │ [0.55,1.6500001,3.3000002,6.085] │ [0.55,1.65,3.30,6.08] │
+└───────────┴──────────────────────────────────┴───────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraymovingsum.md b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraymovingsum.md
new file mode 100644
index 00000000000..563280b7dec
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraymovingsum.md
@@ -0,0 +1,76 @@
+---
+sidebar_position: 113
+---
+
+# groupArrayMovingSum {#agg_function-grouparraymovingsum}
+
+Calculates the moving sum of input values.
+
+``` sql
+groupArrayMovingSum(numbers_for_summing)
+groupArrayMovingSum(window_size)(numbers_for_summing)
+```
+
+The function can take the window size as a parameter. If left unspecified, the function takes the window size equal to the number of rows in the column.
+
+**Arguments**
+
+-   `numbers_for_summing` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) resulting in a numeric data type value.
+-   `window_size` — Size of the calculation window.
+
+**Returned values**
+
+-   Array of the same size and type as the input data.
+
+**Example**
+
+The sample table:
+
+``` sql
+CREATE TABLE t
+(
+    `int` UInt8,
+    `float` Float32,
+    `dec` Decimal32(2)
+)
+ENGINE = TinyLog
+```
+
+``` text
+┌─int─┬─float─┬──dec─┐
+│   1 │   1.1 │ 1.10 │
+│   2 │   2.2 │ 2.20 │
+│   4 │   4.4 │ 4.40 │
+│   7 │  7.77 │ 7.77 │
+└─────┴───────┴──────┘
+```
+
+The queries:
+
+``` sql
+SELECT
+    groupArrayMovingSum(int) AS I,
+    groupArrayMovingSum(float) AS F,
+    groupArrayMovingSum(dec) AS D
+FROM t
+```
+
+``` text
+┌─I──────────┬─F───────────────────────────────┬─D──────────────────────┐
+│ [1,3,7,14] │ [1.1,3.3000002,7.7000003,15.47] │ [1.10,3.30,7.70,15.47] │
+└────────────┴─────────────────────────────────┴────────────────────────┘
+```
+
+``` sql
+SELECT
+    groupArrayMovingSum(2)(int) AS I,
+    groupArrayMovingSum(2)(float) AS F,
+    groupArrayMovingSum(2)(dec) AS D
+FROM t
+```
+
+``` text
+┌─I──────────┬─F───────────────────────────────┬─D──────────────────────┐
+│ [1,3,6,11] │ [1.1,3.3000002,6.6000004,12.17] │ [1.10,3.30,6.60,12.17] │
+└────────────┴─────────────────────────────────┴────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraysample.md b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraysample.md
new file mode 100644
index 00000000000..f0406ddc93c
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraysample.md
@@ -0,0 +1,81 @@
+---
+sidebar_position: 114
+---
+
+# groupArraySample {#grouparraysample}
+
+Creates an array of sample argument values. The size of the resulting array is limited to `max_size` elements. Argument values are selected and added to the array randomly.
+
+**Syntax**
+
+``` sql
+groupArraySample(max_size[, seed])(x)
+```
+
+**Arguments**
+
+-   `max_size` — Maximum size of the resulting array. [UInt64](../../data-types/int-uint.md).
+-   `seed` — Seed for the random number generator. Optional. [UInt64](../../data-types/int-uint.md). Default value: `123456`.
+-   `x` — Argument (column name or expression).
+
+**Returned values**
+
+-   Array of randomly selected `x` arguments.
+
+Type: [Array](../../data-types/array.md).
+
+**Examples**
+
+Consider table `colors`:
+
+``` text
+┌─id─┬─color──┐
+│  1 │ red    │
+│  2 │ blue   │
+│  3 │ green  │
+│  4 │ white  │
+│  5 │ orange │
+└────┴────────┘
+```
+
+Query with column name as argument:
+
+``` sql
+SELECT groupArraySample(3)(color) as newcolors FROM colors;
+```
+
+Result:
+
+```text
+┌─newcolors──────────────────┐
+│ ['white','blue','green']   │
+└────────────────────────────┘
+```
+
+Query with column name and different seed:
+
+``` sql
+SELECT groupArraySample(3, 987654321)(color) as newcolors FROM colors;
+```
+
+Result:
+
+```text
+┌─newcolors──────────────────┐
+│ ['red','orange','green']   │
+└────────────────────────────┘
+```
+
+Query with expression as argument:
+
+``` sql
+SELECT groupArraySample(3)(concat('light-', color)) as newcolors FROM colors;
+```
+
+Result:
+
+```text
+┌─newcolors───────────────────────────────────┐
+│ ['light-blue','light-orange','light-green'] │
+└─────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraysorted.md b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraysorted.md
new file mode 100644
index 00000000000..e34fcbc5788
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/grouparraysorted.md
@@ -0,0 +1,48 @@
+---
+sidebar_position: 108
+---
+
+# groupArraySorted {#groupArraySorted}
+
+Returns an array with the first N items in ascending order.
+
+``` sql
+groupArraySorted(N)(column)
+```
+
+**Arguments**
+
+-   `N` – The number of elements to return.
+
+If the parameter is omitted, default value 10 is used.
+
+**Arguments**
+
+-   `column` – The value.
+-   `expr` — Optional. The field or expresion to sort by. If not set values are sorted by themselves.
+
+**Example**
+
+Gets the first 10 numbers:
+
+``` sql
+SELECT groupArraySorted(10)(number) FROM numbers(100)
+```
+
+``` text
+┌─groupArraySorted(10)(number)─┐
+│ [0,1,2,3,4,5,6,7,8,9]        │
+└──────────────────────────────┘
+```
+
+Or the last 10:
+
+``` sql
+SELECT groupArraySorted(10)(number, -number) FROM numbers(100)
+```
+
+``` text
+┌─groupArraySorted(10)(number, negate(number))─┐
+│ [99,98,97,96,95,94,93,92,91,90]              │
+└──────────────────────────────────────────────┘
+```
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitand.md b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitand.md
new file mode 100644
index 00000000000..0ebb9aec495
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitand.md
@@ -0,0 +1,46 @@
+---
+sidebar_position: 125
+---
+
+# groupBitAnd {#groupbitand}
+
+Applies bitwise `AND` for series of numbers.
+
+``` sql
+groupBitAnd(expr)
+```
+
+**Arguments**
+
+`expr` – An expression that results in `UInt*` type.
+
+**Return value**
+
+Value of the `UInt*` type.
+
+**Example**
+
+Test data:
+
+``` text
+binary     decimal
+00101100 = 44
+00011100 = 28
+00001101 = 13
+01010101 = 85
+```
+
+Query:
+
+``` sql
+SELECT groupBitAnd(num) FROM t
+```
+
+Where `num` is the column with the test data.
+
+Result:
+
+``` text
+binary     decimal
+00000100 = 4
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmap.md b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmap.md
new file mode 100644
index 00000000000..7f1fee6a9f0
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmap.md
@@ -0,0 +1,44 @@
+---
+sidebar_position: 128
+---
+
+# groupBitmap {#groupbitmap}
+
+Bitmap or Aggregate calculations from a unsigned integer column, return cardinality of type UInt64, if add suffix -State, then return [bitmap object](../../../sql-reference/functions/bitmap-functions.md).
+
+``` sql
+groupBitmap(expr)
+```
+
+**Arguments**
+
+`expr` – An expression that results in `UInt*` type.
+
+**Return value**
+
+Value of the `UInt64` type.
+
+**Example**
+
+Test data:
+
+``` text
+UserID
+1
+1
+2
+3
+```
+
+Query:
+
+``` sql
+SELECT groupBitmap(UserID) as num FROM t
+```
+
+Result:
+
+``` text
+num
+3
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmapand.md b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmapand.md
new file mode 100644
index 00000000000..89c94547f8b
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmapand.md
@@ -0,0 +1,46 @@
+---
+sidebar_position: 129
+---
+
+# groupBitmapAnd {#groupbitmapand}
+
+Calculations the AND of a bitmap column, return cardinality of type UInt64, if add suffix -State, then return [bitmap object](../../../sql-reference/functions/bitmap-functions.md).
+
+``` sql
+groupBitmapAnd(expr)
+```
+
+**Arguments**
+
+`expr` – An expression that results in `AggregateFunction(groupBitmap, UInt*)` type.
+
+**Return value**
+
+Value of the `UInt64` type.
+
+**Example**
+
+``` sql
+DROP TABLE IF EXISTS bitmap_column_expr_test2;
+CREATE TABLE bitmap_column_expr_test2
+(
+    tag_id String,
+    z AggregateFunction(groupBitmap, UInt32)
+)
+ENGINE = MergeTree
+ORDER BY tag_id;
+
+INSERT INTO bitmap_column_expr_test2 VALUES ('tag1', bitmapBuild(cast([1,2,3,4,5,6,7,8,9,10] as Array(UInt32))));
+INSERT INTO bitmap_column_expr_test2 VALUES ('tag2', bitmapBuild(cast([6,7,8,9,10,11,12,13,14,15] as Array(UInt32))));
+INSERT INTO bitmap_column_expr_test2 VALUES ('tag3', bitmapBuild(cast([2,4,6,8,10,12] as Array(UInt32))));
+
+SELECT groupBitmapAnd(z) FROM bitmap_column_expr_test2 WHERE like(tag_id, 'tag%');
+┌─groupBitmapAnd(z)─┐
+│               3   │
+└───────────────────┘
+
+SELECT arraySort(bitmapToArray(groupBitmapAndState(z))) FROM bitmap_column_expr_test2 WHERE like(tag_id, 'tag%');
+┌─arraySort(bitmapToArray(groupBitmapAndState(z)))─┐
+│ [6,8,10]                                         │
+└──────────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmapor.md b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmapor.md
new file mode 100644
index 00000000000..172a3bb29ac
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmapor.md
@@ -0,0 +1,46 @@
+---
+sidebar_position: 130
+---
+
+# groupBitmapOr {#groupbitmapor}
+
+Calculations the OR of a bitmap column, return cardinality of type UInt64, if add suffix -State, then return [bitmap object](../../../sql-reference/functions/bitmap-functions.md). This is equivalent to `groupBitmapMerge`.
+
+``` sql
+groupBitmapOr(expr)
+```
+
+**Arguments**
+
+`expr` – An expression that results in `AggregateFunction(groupBitmap, UInt*)` type.
+
+**Returned value**
+
+Value of the `UInt64` type.
+
+**Example**
+
+``` sql
+DROP TABLE IF EXISTS bitmap_column_expr_test2;
+CREATE TABLE bitmap_column_expr_test2
+(
+    tag_id String,
+    z AggregateFunction(groupBitmap, UInt32)
+)
+ENGINE = MergeTree
+ORDER BY tag_id;
+
+INSERT INTO bitmap_column_expr_test2 VALUES ('tag1', bitmapBuild(cast([1,2,3,4,5,6,7,8,9,10] as Array(UInt32))));
+INSERT INTO bitmap_column_expr_test2 VALUES ('tag2', bitmapBuild(cast([6,7,8,9,10,11,12,13,14,15] as Array(UInt32))));
+INSERT INTO bitmap_column_expr_test2 VALUES ('tag3', bitmapBuild(cast([2,4,6,8,10,12] as Array(UInt32))));
+
+SELECT groupBitmapOr(z) FROM bitmap_column_expr_test2 WHERE like(tag_id, 'tag%');
+┌─groupBitmapOr(z)─┐
+│             15   │
+└──────────────────┘
+
+SELECT arraySort(bitmapToArray(groupBitmapOrState(z))) FROM bitmap_column_expr_test2 WHERE like(tag_id, 'tag%');
+┌─arraySort(bitmapToArray(groupBitmapOrState(z)))─┐
+│ [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]           │
+└─────────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmapxor.md b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmapxor.md
new file mode 100644
index 00000000000..52c45815cc5
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitmapxor.md
@@ -0,0 +1,46 @@
+---
+sidebar_position: 131
+---
+
+# groupBitmapXor {#groupbitmapxor}
+
+Calculations the XOR of a bitmap column, return cardinality of type UInt64, if add suffix -State, then return [bitmap object](../../../sql-reference/functions/bitmap-functions.md).
+
+``` sql
+groupBitmapOr(expr)
+```
+
+**Arguments**
+
+`expr` – An expression that results in `AggregateFunction(groupBitmap, UInt*)` type.
+
+**Returned value**
+
+Value of the `UInt64` type.
+
+**Example**
+
+``` sql
+DROP TABLE IF EXISTS bitmap_column_expr_test2;
+CREATE TABLE bitmap_column_expr_test2
+(
+    tag_id String,
+    z AggregateFunction(groupBitmap, UInt32)
+)
+ENGINE = MergeTree
+ORDER BY tag_id;
+
+INSERT INTO bitmap_column_expr_test2 VALUES ('tag1', bitmapBuild(cast([1,2,3,4,5,6,7,8,9,10] as Array(UInt32))));
+INSERT INTO bitmap_column_expr_test2 VALUES ('tag2', bitmapBuild(cast([6,7,8,9,10,11,12,13,14,15] as Array(UInt32))));
+INSERT INTO bitmap_column_expr_test2 VALUES ('tag3', bitmapBuild(cast([2,4,6,8,10,12] as Array(UInt32))));
+
+SELECT groupBitmapXor(z) FROM bitmap_column_expr_test2 WHERE like(tag_id, 'tag%');
+┌─groupBitmapXor(z)─┐
+│              10   │
+└───────────────────┘
+
+SELECT arraySort(bitmapToArray(groupBitmapXorState(z))) FROM bitmap_column_expr_test2 WHERE like(tag_id, 'tag%');
+┌─arraySort(bitmapToArray(groupBitmapXorState(z)))─┐
+│ [1,3,5,6,8,10,11,13,14,15]                       │
+└──────────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitor.md b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitor.md
new file mode 100644
index 00000000000..c1ee1c40894
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitor.md
@@ -0,0 +1,46 @@
+---
+sidebar_position: 126
+---
+
+# groupBitOr {#groupbitor}
+
+Applies bitwise `OR` for series of numbers.
+
+``` sql
+groupBitOr(expr)
+```
+
+**Arguments**
+
+`expr` – An expression that results in `UInt*` type.
+
+**Returned value**
+
+Value of the `UInt*` type.
+
+**Example**
+
+Test data:
+
+``` text
+binary     decimal
+00101100 = 44
+00011100 = 28
+00001101 = 13
+01010101 = 85
+```
+
+Query:
+
+``` sql
+SELECT groupBitOr(num) FROM t
+```
+
+Where `num` is the column with the test data.
+
+Result:
+
+``` text
+binary     decimal
+01111101 = 125
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitxor.md b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitxor.md
new file mode 100644
index 00000000000..472bcdf65c1
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/groupbitxor.md
@@ -0,0 +1,46 @@
+---
+sidebar_position: 127
+---
+
+# groupBitXor {#groupbitxor}
+
+Applies bitwise `XOR` for series of numbers.
+
+``` sql
+groupBitXor(expr)
+```
+
+**Arguments**
+
+`expr` – An expression that results in `UInt*` type.
+
+**Return value**
+
+Value of the `UInt*` type.
+
+**Example**
+
+Test data:
+
+``` text
+binary     decimal
+00101100 = 44
+00011100 = 28
+00001101 = 13
+01010101 = 85
+```
+
+Query:
+
+``` sql
+SELECT groupBitXor(num) FROM t
+```
+
+Where `num` is the column with the test data.
+
+Result:
+
+``` text
+binary     decimal
+01101000 = 104
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/groupuniqarray.md b/docs/en/reference/sql-reference/aggregate-functions/reference/groupuniqarray.md
new file mode 100644
index 00000000000..9b5058032e5
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/groupuniqarray.md
@@ -0,0 +1,12 @@
+---
+sidebar_position: 111
+---
+
+# groupUniqArray {#groupuniqarray}
+
+Syntax: `groupUniqArray(x)` or `groupUniqArray(max_size)(x)`
+
+Creates an array from different argument values. Memory consumption is the same as for the [uniqExact](../../../sql-reference/aggregate-functions/reference/uniqexact.md) function.
+
+The second version (with the `max_size` parameter) limits the size of the resulting array to `max_size` elements.
+For example, `groupUniqArray(1)(x)` is equivalent to `[any(x)]`.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/index.md b/docs/en/reference/sql-reference/aggregate-functions/reference/index.md
new file mode 100644
index 00000000000..cd71bca2556
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/index.md
@@ -0,0 +1,76 @@
+---
+toc_folder_title: Reference
+sidebar_position: 36
+toc_hidden: true
+---
+
+# List of Aggregate Functions {#aggregate-functions-reference}
+
+Standard aggregate functions:
+
+-   [count](../../../sql-reference/aggregate-functions/reference/count.md)
+-   [min](../../../sql-reference/aggregate-functions/reference/min.md)
+-   [max](../../../sql-reference/aggregate-functions/reference/max.md)
+-   [sum](../../../sql-reference/aggregate-functions/reference/sum.md)
+-   [avg](../../../sql-reference/aggregate-functions/reference/avg.md)
+-   [any](../../../sql-reference/aggregate-functions/reference/any.md)
+-   [stddevPop](../../../sql-reference/aggregate-functions/reference/stddevpop.md)
+-   [stddevSamp](../../../sql-reference/aggregate-functions/reference/stddevsamp.md)
+-   [varPop](../../../sql-reference/aggregate-functions/reference/varpop.md)
+-   [varSamp](../../../sql-reference/aggregate-functions/reference/varsamp.md)
+-   [covarPop](../../../sql-reference/aggregate-functions/reference/covarpop.md)
+-   [covarSamp](../../../sql-reference/aggregate-functions/reference/covarsamp.md)
+
+ClickHouse-specific aggregate functions:
+
+-   [anyHeavy](../../../sql-reference/aggregate-functions/reference/anyheavy.md)
+-   [anyLast](../../../sql-reference/aggregate-functions/reference/anylast.md)
+-   [argMin](../../../sql-reference/aggregate-functions/reference/argmin.md)
+-   [argMax](../../../sql-reference/aggregate-functions/reference/argmax.md)
+-   [avgWeighted](../../../sql-reference/aggregate-functions/reference/avgweighted.md)
+-   [topK](../../../sql-reference/aggregate-functions/reference/topk.md)
+-   [topKWeighted](../../../sql-reference/aggregate-functions/reference/topkweighted.md)
+-   [groupArray](../../../sql-reference/aggregate-functions/reference/grouparray.md)
+-   [groupUniqArray](../../../sql-reference/aggregate-functions/reference/groupuniqarray.md)
+-   [groupArrayInsertAt](../../../sql-reference/aggregate-functions/reference/grouparrayinsertat.md)
+-   [groupArrayMovingAvg](../../../sql-reference/aggregate-functions/reference/grouparraymovingavg.md)
+-   [groupArrayMovingSum](../../../sql-reference/aggregate-functions/reference/grouparraymovingsum.md)
+-   [groupBitAnd](../../../sql-reference/aggregate-functions/reference/groupbitand.md)
+-   [groupBitOr](../../../sql-reference/aggregate-functions/reference/groupbitor.md)
+-   [groupBitXor](../../../sql-reference/aggregate-functions/reference/groupbitxor.md)
+-   [groupBitmap](../../../sql-reference/aggregate-functions/reference/groupbitmap.md)
+-   [groupBitmapAnd](../../../sql-reference/aggregate-functions/reference/groupbitmapand.md)
+-   [groupBitmapOr](../../../sql-reference/aggregate-functions/reference/groupbitmapor.md)
+-   [groupBitmapXor](../../../sql-reference/aggregate-functions/reference/groupbitmapxor.md)
+-   [sumWithOverflow](../../../sql-reference/aggregate-functions/reference/sumwithoverflow.md)
+-   [sumMap](../../../sql-reference/aggregate-functions/reference/summap.md)
+-   [minMap](../../../sql-reference/aggregate-functions/reference/minmap.md)
+-   [maxMap](../../../sql-reference/aggregate-functions/reference/maxmap.md)
+-   [skewSamp](../../../sql-reference/aggregate-functions/reference/skewsamp.md)
+-   [skewPop](../../../sql-reference/aggregate-functions/reference/skewpop.md)
+-   [kurtSamp](../../../sql-reference/aggregate-functions/reference/kurtsamp.md)
+-   [kurtPop](../../../sql-reference/aggregate-functions/reference/kurtpop.md)
+-   [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md)
+-   [uniqExact](../../../sql-reference/aggregate-functions/reference/uniqexact.md)
+-   [uniqCombined](../../../sql-reference/aggregate-functions/reference/uniqcombined.md)
+-   [uniqCombined64](../../../sql-reference/aggregate-functions/reference/uniqcombined64.md)
+-   [uniqHLL12](../../../sql-reference/aggregate-functions/reference/uniqhll12.md)
+-   [quantile](../../../sql-reference/aggregate-functions/reference/quantile.md)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md)
+-   [quantileExact](../../../sql-reference/aggregate-functions/reference/quantileexact.md)
+-   [quantileExactLow](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexactlow)
+-   [quantileExactHigh](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexacthigh)
+-   [quantileExactWeighted](../../../sql-reference/aggregate-functions/reference/quantileexactweighted.md)
+-   [quantileTiming](../../../sql-reference/aggregate-functions/reference/quantiletiming.md)
+-   [quantileTimingWeighted](../../../sql-reference/aggregate-functions/reference/quantiletimingweighted.md)
+-   [quantileDeterministic](../../../sql-reference/aggregate-functions/reference/quantiledeterministic.md)
+-   [quantileTDigest](../../../sql-reference/aggregate-functions/reference/quantiletdigest.md)
+-   [quantileTDigestWeighted](../../../sql-reference/aggregate-functions/reference/quantiletdigestweighted.md)
+-   [quantileBFloat16](../../../sql-reference/aggregate-functions/reference/quantilebfloat16.md#quantilebfloat16)
+-   [quantileBFloat16Weighted](../../../sql-reference/aggregate-functions/reference/quantilebfloat16.md#quantilebfloat16weighted)
+-   [simpleLinearRegression](../../../sql-reference/aggregate-functions/reference/simplelinearregression.md)
+-   [stochasticLinearRegression](../../../sql-reference/aggregate-functions/reference/stochasticlinearregression.md)
+-   [stochasticLogisticRegression](../../../sql-reference/aggregate-functions/reference/stochasticlogisticregression.md)
+-   [categoricalInformationValue](../../../sql-reference/aggregate-functions/reference/categoricalinformationvalue.md)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/aggregate-functions/reference/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/intervalLengthSum.md b/docs/en/reference/sql-reference/aggregate-functions/reference/intervalLengthSum.md
new file mode 100644
index 00000000000..33c5686cbbc
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/intervalLengthSum.md
@@ -0,0 +1,108 @@
+---
+sidebar_position: 146
+sidebar_label: intervalLengthSum
+---
+
+# intervalLengthSum {#agg_function-intervallengthsum}
+
+Calculates the total length of union of all ranges (segments on numeric axis).
+
+**Syntax**
+
+``` sql
+intervalLengthSum(start, end)
+```
+
+**Arguments**
+
+-   `start` — The starting value of the interval. [Int32](../../../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-int8-int16-int32-int64), [Int64](../../../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-int8-int16-int32-int64), [UInt32](../../../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-int8-int16-int32-int64), [UInt64](../../../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-int8-int16-int32-int64), [Float32](../../../sql-reference/data-types/float.md#float32-float64), [Float64](../../../sql-reference/data-types/float.md#float32-float64), [DateTime](../../../sql-reference/data-types/datetime.md#data_type-datetime) or [Date](../../../sql-reference/data-types/date.md#data_type-date).
+-   `end` — The ending value of the interval. [Int32](../../../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-int8-int16-int32-int64), [Int64](../../../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-int8-int16-int32-int64), [UInt32](../../../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-int8-int16-int32-int64), [UInt64](../../../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-int8-int16-int32-int64), [Float32](../../../sql-reference/data-types/float.md#float32-float64), [Float64](../../../sql-reference/data-types/float.md#float32-float64), [DateTime](../../../sql-reference/data-types/datetime.md#data_type-datetime) or [Date](../../../sql-reference/data-types/date.md#data_type-date).
+
+:::note    
+Arguments must be of the same data type. Otherwise, an exception will be thrown.
+:::
+
+**Returned value**
+
+-   Total length of union of all ranges (segments on numeric axis). Depending on the type of the argument, the return value may be [UInt64](../../../sql-reference/data-types/int-uint.md#uint8-uint16-uint32-uint64-int8-int16-int32-int64) or [Float64](../../../sql-reference/data-types/float.md#float32-float64) type.
+
+**Examples**
+
+1. Input table:
+
+``` text
+┌─id─┬─start─┬─end─┐
+│ a  │   1.1 │ 2.9 │
+│ a  │   2.5 │ 3.2 │
+│ a  │     4 │   5 │
+└────┴───────┴─────┘
+```
+
+In this example, the arguments of the Float32 type are used. The function returns a value of the Float64 type.
+
+Result is the sum of lengths of intervals `[1.1, 3.2]` (union of `[1.1, 2.9]` and `[2.5, 3.2]`) and `[4, 5]`
+
+Query:
+
+``` sql
+SELECT id, intervalLengthSum(start, end), toTypeName(intervalLengthSum(start, end)) FROM fl_interval GROUP BY id ORDER BY id;
+```
+
+Result:
+
+``` text
+┌─id─┬─intervalLengthSum(start, end)─┬─toTypeName(intervalLengthSum(start, end))─┐
+│ a  │                           3.1 │ Float64                                   │
+└────┴───────────────────────────────┴───────────────────────────────────────────┘
+```
+
+2. Input table:
+
+``` text
+┌─id─┬───────────────start─┬─────────────────end─┐
+│ a  │ 2020-01-01 01:12:30 │ 2020-01-01 02:10:10 │
+│ a  │ 2020-01-01 02:05:30 │ 2020-01-01 02:50:31 │
+│ a  │ 2020-01-01 03:11:22 │ 2020-01-01 03:23:31 │
+└────┴─────────────────────┴─────────────────────┘
+```
+
+In this example, the arguments of the DateTime type are used. The function returns a value in seconds.
+
+Query:
+
+``` sql
+SELECT id, intervalLengthSum(start, end), toTypeName(intervalLengthSum(start, end)) FROM dt_interval GROUP BY id ORDER BY id;
+```
+
+Result:
+
+``` text
+┌─id─┬─intervalLengthSum(start, end)─┬─toTypeName(intervalLengthSum(start, end))─┐
+│ a  │                          6610 │ UInt64                                    │
+└────┴───────────────────────────────┴───────────────────────────────────────────┘
+```
+
+3. Input table:
+
+``` text
+┌─id─┬──────start─┬────────end─┐
+│ a  │ 2020-01-01 │ 2020-01-04 │
+│ a  │ 2020-01-12 │ 2020-01-18 │
+└────┴────────────┴────────────┘
+```
+
+In this example, the arguments of the Date type are used. The function returns a value in days.
+
+Query:
+
+``` sql
+SELECT id, intervalLengthSum(start, end), toTypeName(intervalLengthSum(start, end)) FROM date_interval GROUP BY id ORDER BY id;
+```
+
+Result:
+
+``` text
+┌─id─┬─intervalLengthSum(start, end)─┬─toTypeName(intervalLengthSum(start, end))─┐
+│ a  │                             9 │ UInt64                                    │
+└────┴───────────────────────────────┴───────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/kurtpop.md b/docs/en/reference/sql-reference/aggregate-functions/reference/kurtpop.md
new file mode 100644
index 00000000000..5640e69ba7c
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/kurtpop.md
@@ -0,0 +1,25 @@
+---
+sidebar_position: 153
+---
+
+# kurtPop {#kurtpop}
+
+Computes the [kurtosis](https://en.wikipedia.org/wiki/Kurtosis) of a sequence.
+
+``` sql
+kurtPop(expr)
+```
+
+**Arguments**
+
+`expr` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) returning a number.
+
+**Returned value**
+
+The kurtosis of the given distribution. Type — [Float64](../../../sql-reference/data-types/float.md)
+
+**Example**
+
+``` sql
+SELECT kurtPop(value) FROM series_with_value_column;
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/kurtsamp.md b/docs/en/reference/sql-reference/aggregate-functions/reference/kurtsamp.md
new file mode 100644
index 00000000000..c0768edaf2d
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/kurtsamp.md
@@ -0,0 +1,27 @@
+---
+sidebar_position: 154
+---
+
+# kurtSamp {#kurtsamp}
+
+Computes the [sample kurtosis](https://en.wikipedia.org/wiki/Kurtosis) of a sequence.
+
+It represents an unbiased estimate of the kurtosis of a random variable if passed values form its sample.
+
+``` sql
+kurtSamp(expr)
+```
+
+**Arguments**
+
+`expr` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) returning a number.
+
+**Returned value**
+
+The kurtosis of the given distribution. Type — [Float64](../../../sql-reference/data-types/float.md). If `n <= 1` (`n` is a size of the sample), then the function returns `nan`.
+
+**Example**
+
+``` sql
+SELECT kurtSamp(value) FROM series_with_value_column;
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/mannwhitneyutest.md b/docs/en/reference/sql-reference/aggregate-functions/reference/mannwhitneyutest.md
new file mode 100644
index 00000000000..32e56b8de10
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/mannwhitneyutest.md
@@ -0,0 +1,74 @@
+---
+sidebar_position: 310
+sidebar_label: mannWhitneyUTest
+---
+
+# mannWhitneyUTest {#mannwhitneyutest}
+
+Applies the Mann-Whitney rank test to samples from two populations.
+
+**Syntax**
+
+``` sql
+mannWhitneyUTest[(alternative[, continuity_correction])](sample_data, sample_index)
+```
+
+Values of both samples are in the `sample_data` column. If `sample_index` equals to 0 then the value in that row belongs to the sample from the first population. Otherwise it belongs to the sample from the second population.
+The null hypothesis is that two populations are stochastically equal. Also one-sided hypothesises can be tested. This test does not assume that data have normal distribution.
+
+**Arguments**
+
+-   `sample_data` — sample data. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
+-   `sample_index` — sample index. [Integer](../../../sql-reference/data-types/int-uint.md).
+
+**Parameters**
+
+-   `alternative` — alternative hypothesis. (Optional, default: `'two-sided'`.) [String](../../../sql-reference/data-types/string.md).
+    -   `'two-sided'`;
+    -   `'greater'`;
+    -   `'less'`.
+-   `continuity_correction` — if not 0 then continuity correction in the normal approximation for the p-value is applied. (Optional, default: 1.) [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+[Tuple](../../../sql-reference/data-types/tuple.md) with two elements:
+
+-   calculated U-statistic. [Float64](../../../sql-reference/data-types/float.md).
+-   calculated p-value. [Float64](../../../sql-reference/data-types/float.md).
+
+
+**Example**
+
+Input table:
+
+``` text
+┌─sample_data─┬─sample_index─┐
+│          10 │            0 │
+│          11 │            0 │
+│          12 │            0 │
+│           1 │            1 │
+│           2 │            1 │
+│           3 │            1 │
+└─────────────┴──────────────┘
+```
+
+Query:
+
+``` sql
+SELECT mannWhitneyUTest('greater')(sample_data, sample_index) FROM mww_ttest;
+```
+
+Result:
+
+``` text
+┌─mannWhitneyUTest('greater')(sample_data, sample_index)─┐
+│ (9,0.04042779918503192)                                │
+└────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [Mann–Whitney U test](https://en.wikipedia.org/wiki/Mann%E2%80%93Whitney_U_test)
+-   [Stochastic ordering](https://en.wikipedia.org/wiki/Stochastic_ordering)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/aggregate-functions/reference/mannwhitneyutest/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/max.md b/docs/en/reference/sql-reference/aggregate-functions/reference/max.md
new file mode 100644
index 00000000000..845d0c5ecee
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/max.md
@@ -0,0 +1,24 @@
+---
+sidebar_position: 3
+---
+
+# max {#agg_function-max}
+
+Aggregate function that calculates the maximum across a group of values.
+
+Example:
+
+```
+SELECT max(salary) FROM employees;
+```
+
+```
+SELECT department, max(salary) FROM employees GROUP BY department;
+```
+
+If you need non-aggregate function to choose a maximum of two values, see `greatest`:
+
+```
+SELECT greatest(a, b) FROM table;
+```
+
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/maxmap.md b/docs/en/reference/sql-reference/aggregate-functions/reference/maxmap.md
new file mode 100644
index 00000000000..243a3375552
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/maxmap.md
@@ -0,0 +1,28 @@
+---
+sidebar_position: 143
+---
+
+# maxMap {#agg_functions-maxmap}
+
+Syntax: `maxMap(key, value)` or `maxMap(Tuple(key, value))`
+
+Calculates the maximum from `value` array according to the keys specified in the `key` array.
+
+Passing a tuple of keys and value arrays is identical to passing two arrays of keys and values.
+
+The number of elements in `key` and `value` must be the same for each row that is totaled.
+
+Returns a tuple of two arrays: keys and values calculated for the corresponding keys.
+
+Example:
+
+``` sql
+SELECT maxMap(a, b)
+FROM values('a Array(Int32), b Array(Int64)', ([1, 2], [2, 2]), ([2, 3], [1, 1]))
+```
+
+``` text
+┌─maxMap(a, b)──────┐
+│ ([1,2,3],[2,2,1]) │
+└───────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/meanztest.md b/docs/en/reference/sql-reference/aggregate-functions/reference/meanztest.md
new file mode 100644
index 00000000000..02b89b1b31d
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/meanztest.md
@@ -0,0 +1,70 @@
+---
+sidebar_position: 303
+sidebar_label: meanZTest
+---
+
+# meanZTest {#meanztest}
+
+Applies mean z-test to samples from two populations.
+
+**Syntax**
+
+``` sql
+meanZTest(population_variance_x, population_variance_y, confidence_level)(sample_data, sample_index)
+```
+
+Values of both samples are in the `sample_data` column. If `sample_index` equals to 0 then the value in that row belongs to the sample from the first population. Otherwise it belongs to the sample from the second population.
+The null hypothesis is that means of populations are equal. Normal distribution is assumed. Populations may have unequal variance and the variances are known.
+
+**Arguments**
+
+-   `sample_data` — Sample data. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
+-   `sample_index` — Sample index. [Integer](../../../sql-reference/data-types/int-uint.md).
+
+**Parameters**
+
+-   `population_variance_x` — Variance for population x. [Float](../../../sql-reference/data-types/float.md).
+-   `population_variance_y` — Variance for population y. [Float](../../../sql-reference/data-types/float.md).
+-   `confidence_level` — Confidence level in order to calculate confidence intervals. [Float](../../../sql-reference/data-types/float.md).
+
+**Returned values**
+
+[Tuple](../../../sql-reference/data-types/tuple.md) with four elements:
+
+-   calculated t-statistic. [Float64](../../../sql-reference/data-types/float.md).
+-   calculated p-value. [Float64](../../../sql-reference/data-types/float.md).
+-   calculated confidence-interval-low. [Float64](../../../sql-reference/data-types/float.md).
+-   calculated confidence-interval-high. [Float64](../../../sql-reference/data-types/float.md).
+
+
+**Example**
+
+Input table:
+
+``` text
+┌─sample_data─┬─sample_index─┐
+│        20.3 │            0 │
+│        21.9 │            0 │
+│        22.1 │            0 │
+│        18.9 │            1 │
+│          19 │            1 │
+│        20.3 │            1 │
+└─────────────┴──────────────┘
+```
+
+Query:
+
+``` sql
+SELECT meanZTest(0.7, 0.45, 0.95)(sample_data, sample_index) FROM mean_ztest
+```
+
+Result:
+
+``` text
+┌─meanZTest(0.7, 0.45, 0.95)(sample_data, sample_index)────────────────────────────┐
+│ (3.2841296025548123,0.0010229786769086013,0.8198428246768334,3.2468238419898365) │
+└──────────────────────────────────────────────────────────────────────────────────┘
+```
+
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/aggregate-functions/reference/meanZTest/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/median.md b/docs/en/reference/sql-reference/aggregate-functions/reference/median.md
new file mode 100644
index 00000000000..3e84b4b169c
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/median.md
@@ -0,0 +1,46 @@
+---
+sidebar_position: 212
+---
+
+# median {#median}
+
+The `median*` functions are the aliases for the corresponding `quantile*` functions. They calculate median of a numeric data sample.
+
+Functions:
+
+-   `median` — Alias for [quantile](../../../sql-reference/aggregate-functions/reference/quantile.md#quantile).
+-   `medianDeterministic` — Alias for [quantileDeterministic](../../../sql-reference/aggregate-functions/reference/quantiledeterministic.md#quantiledeterministic).
+-   `medianExact` — Alias for [quantileExact](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexact).
+-   `medianExactWeighted` — Alias for [quantileExactWeighted](../../../sql-reference/aggregate-functions/reference/quantileexactweighted.md#quantileexactweighted).
+-   `medianTiming` — Alias for [quantileTiming](../../../sql-reference/aggregate-functions/reference/quantiletiming.md#quantiletiming).
+-   `medianTimingWeighted` — Alias for [quantileTimingWeighted](../../../sql-reference/aggregate-functions/reference/quantiletimingweighted.md#quantiletimingweighted).
+-   `medianTDigest` — Alias for [quantileTDigest](../../../sql-reference/aggregate-functions/reference/quantiletdigest.md#quantiletdigest).
+-   `medianTDigestWeighted` — Alias for [quantileTDigestWeighted](../../../sql-reference/aggregate-functions/reference/quantiletdigestweighted.md#quantiletdigestweighted).
+-   `medianBFloat16` — Alias for [quantileBFloat16](../../../sql-reference/aggregate-functions/reference/quantilebfloat16.md#quantilebfloat16).
+
+**Example**
+
+Input table:
+
+``` text
+┌─val─┐
+│   1 │
+│   1 │
+│   2 │
+│   3 │
+└─────┘
+```
+
+Query:
+
+``` sql
+SELECT medianDeterministic(val, 1) FROM t;
+```
+
+Result:
+
+``` text
+┌─medianDeterministic(val, 1)─┐
+│                         1.5 │
+└─────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/min.md b/docs/en/reference/sql-reference/aggregate-functions/reference/min.md
new file mode 100644
index 00000000000..0525066e9f3
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/min.md
@@ -0,0 +1,23 @@
+---
+sidebar_position: 2
+---
+
+## min {#agg_function-min}
+
+Aggregate function that calculates the minimum across a group of values.
+
+Example:
+
+```
+SELECT min(salary) FROM employees;
+```
+
+```
+SELECT department, min(salary) FROM employees GROUP BY department;
+```
+
+If you need non-aggregate function to choose a minimum of two values, see `least`:
+
+```
+SELECT least(a, b) FROM table;
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/minmap.md b/docs/en/reference/sql-reference/aggregate-functions/reference/minmap.md
new file mode 100644
index 00000000000..8a4d50dd46c
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/minmap.md
@@ -0,0 +1,28 @@
+---
+sidebar_position: 142
+---
+
+# minMap {#agg_functions-minmap}
+
+Syntax: `minMap(key, value)` or `minMap(Tuple(key, value))`
+
+Calculates the minimum from `value` array according to the keys specified in the `key` array.
+
+Passing a tuple of keys and value ​​arrays is identical to passing two arrays of keys and values.
+
+The number of elements in `key` and `value` must be the same for each row that is totaled.
+
+Returns a tuple of two arrays: keys in sorted order, and values calculated for the corresponding keys.
+
+Example:
+
+``` sql
+SELECT minMap(a, b)
+FROM values('a Array(Int32), b Array(Int64)', ([1, 2], [2, 2]), ([2, 3], [1, 1]))
+```
+
+``` text
+┌─minMap(a, b)──────┐
+│ ([1,2,3],[2,1,1]) │
+└───────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantile.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantile.md
new file mode 100644
index 00000000000..6a0479da77f
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantile.md
@@ -0,0 +1,68 @@
+---
+sidebar_position: 200
+---
+
+# quantile {#quantile}
+
+Computes an approximate [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+This function applies [reservoir sampling](https://en.wikipedia.org/wiki/Reservoir_sampling) with a reservoir size up to 8192 and a random number generator for sampling. The result is non-deterministic. To get an exact quantile, use the [quantileExact](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexact) function.
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+Note that for an empty numeric sequence, `quantile` will return NaN, but its `quantile*` variants will return either NaN or a default value for the sequence type, depending on the variant.
+
+**Syntax**
+
+``` sql
+quantile(level)(expr)
+```
+
+Alias: `median`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+-   Approximate quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Input table:
+
+``` text
+┌─val─┐
+│   1 │
+│   1 │
+│   2 │
+│   3 │
+└─────┘
+```
+
+Query:
+
+``` sql
+SELECT quantile(val) FROM t
+```
+
+Result:
+
+``` text
+┌─quantile(val)─┐
+│           1.5 │
+└───────────────┘
+```
+
+**See Also**
+
+-   [median](../../../sql-reference/aggregate-functions/reference/median.md#median)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantilebfloat16.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantilebfloat16.md
new file mode 100644
index 00000000000..f0bd51f0add
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantilebfloat16.md
@@ -0,0 +1,68 @@
+---
+sidebar_position: 209
+---
+
+# quantileBFloat16 {#quantilebfloat16}
+
+Computes an approximate [quantile](https://en.wikipedia.org/wiki/Quantile) of a sample consisting of [bfloat16](https://en.wikipedia.org/wiki/Bfloat16_floating-point_format) numbers. `bfloat16` is a floating-point data type with 1 sign bit, 8 exponent bits and 7 fraction bits.
+The function converts input values to 32-bit floats and takes the most significant 16 bits. Then it calculates `bfloat16` quantile value and converts the result to a 64-bit float by appending zero bits.
+The function is a fast quantile estimator with a relative error no more than 0.390625%.
+
+**Syntax**
+
+``` sql
+quantileBFloat16[(level)](expr)
+```
+
+Alias: `medianBFloat16`
+
+**Arguments**
+
+-   `expr` — Column with numeric data. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md).
+
+**Parameters**
+
+-   `level` — Level of quantile. Optional. Possible values are in the range from 0 to 1. Default value: 0.5. [Float](../../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   Approximate quantile of the specified level.
+
+Type: [Float64](../../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Input table has an integer and a float columns:
+
+``` text
+┌─a─┬─────b─┐
+│ 1 │ 1.001 │
+│ 2 │ 1.002 │
+│ 3 │ 1.003 │
+│ 4 │ 1.004 │
+└───┴───────┘
+```
+
+Query to calculate 0.75-quantile (third quartile):
+
+``` sql
+SELECT quantileBFloat16(0.75)(a), quantileBFloat16(0.75)(b) FROM example_table;
+```
+
+Result:
+
+``` text
+┌─quantileBFloat16(0.75)(a)─┬─quantileBFloat16(0.75)(b)─┐
+│                         3 │                         1 │
+└───────────────────────────┴───────────────────────────┘
+```
+Note that all floating point values in the example are truncated to 1.0 when converting to `bfloat16`.
+
+# quantileBFloat16Weighted {#quantilebfloat16weighted}
+
+Like `quantileBFloat16` but takes into account the weight of each sequence member.
+
+**See Also**
+
+-   [median](../../../sql-reference/aggregate-functions/reference/median.md#median)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantiledeterministic.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiledeterministic.md
new file mode 100644
index 00000000000..bb23ce63cea
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiledeterministic.md
@@ -0,0 +1,67 @@
+---
+sidebar_position: 206
+---
+
+# quantileDeterministic {#quantiledeterministic}
+
+Computes an approximate [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+This function applies [reservoir sampling](https://en.wikipedia.org/wiki/Reservoir_sampling) with a reservoir size up to 8192 and deterministic algorithm of sampling. The result is deterministic. To get an exact quantile, use the [quantileExact](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexact) function.
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+**Syntax**
+
+``` sql
+quantileDeterministic(level)(expr, determinator)
+```
+
+Alias: `medianDeterministic`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+-   `determinator` — Number whose hash is used instead of a random number generator in the reservoir sampling algorithm to make the result of sampling deterministic. As a determinator you can use any deterministic positive number, for example, a user id or an event id. If the same determinator value occures too often, the function works incorrectly.
+
+**Returned value**
+
+-   Approximate quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Input table:
+
+``` text
+┌─val─┐
+│   1 │
+│   1 │
+│   2 │
+│   3 │
+└─────┘
+```
+
+Query:
+
+``` sql
+SELECT quantileDeterministic(val, 1) FROM t
+```
+
+Result:
+
+``` text
+┌─quantileDeterministic(val, 1)─┐
+│                           1.5 │
+└───────────────────────────────┘
+```
+
+**See Also**
+
+-   [median](../../../sql-reference/aggregate-functions/reference/median.md#median)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantileexact.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantileexact.md
new file mode 100644
index 00000000000..b3a384b0cfd
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantileexact.md
@@ -0,0 +1,270 @@
+---
+sidebar_position: 202
+---
+
+# quantileExact Functions {#quantileexact-functions}
+
+## quantileExact {#quantileexact}
+
+Exactly computes the [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+To get exact value, all the passed values ​​are combined into an array, which is then partially sorted. Therefore, the function consumes `O(n)` memory, where `n` is a number of values that were passed. However, for a small number of values, the function is very effective.
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+**Syntax**
+
+``` sql
+quantileExact(level)(expr)
+```
+
+Alias: `medianExact`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+-   Quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT quantileExact(number) FROM numbers(10)
+```
+
+Result:
+
+``` text
+┌─quantileExact(number)─┐
+│                     5 │
+└───────────────────────┘
+```
+
+## quantileExactLow {#quantileexactlow}
+
+Similar to `quantileExact`, this computes the exact [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+To get the exact value, all the passed values are combined into an array, which is then fully sorted.  The sorting [algorithm's](https://en.cppreference.com/w/cpp/algorithm/sort) complexity is `O(N·log(N))`, where `N = std::distance(first, last)` comparisons.
+
+The return value depends on the quantile level and the number of elements in the selection, i.e. if the level is 0.5, then the function returns the lower median value for an even number of elements and the middle median value for an odd number of elements. Median is calculated similarly to the [median_low](https://docs.python.org/3/library/statistics.html#statistics.median_low) implementation which is used in python.
+
+For all other levels, the element at the index corresponding to the value of `level * size_of_array` is returned. For example:
+
+``` sql
+SELECT quantileExactLow(0.1)(number) FROM numbers(10)
+
+┌─quantileExactLow(0.1)(number)─┐
+│                             1 │
+└───────────────────────────────┘
+```
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+**Syntax**
+
+``` sql
+quantileExactLow(level)(expr)
+```
+
+Alias: `medianExactLow`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+-   Quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT quantileExactLow(number) FROM numbers(10)
+```
+
+Result:
+
+``` text
+┌─quantileExactLow(number)─┐
+│                        4 │
+└──────────────────────────┘
+```
+## quantileExactHigh {#quantileexacthigh}
+
+Similar to `quantileExact`, this computes the exact [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+All the passed values are combined into an array, which is then fully sorted, to get the exact value.  The sorting [algorithm's](https://en.cppreference.com/w/cpp/algorithm/sort) complexity is `O(N·log(N))`, where `N = std::distance(first, last)` comparisons.
+
+The return value depends on the quantile level and the number of elements in the selection, i.e. if the level is 0.5, then the function returns the higher median value for an even number of elements and the middle median value for an odd number of elements. Median is calculated similarly to the [median_high](https://docs.python.org/3/library/statistics.html#statistics.median_high) implementation which is used in python. For all other levels, the element at the index corresponding to the value of `level * size_of_array` is returned.
+
+This implementation behaves exactly similar to the current `quantileExact` implementation.
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+**Syntax**
+
+``` sql
+quantileExactHigh(level)(expr)
+```
+
+Alias: `medianExactHigh`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+-   Quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT quantileExactHigh(number) FROM numbers(10)
+```
+
+Result:
+
+``` text
+┌─quantileExactHigh(number)─┐
+│                         5 │
+└───────────────────────────┘
+```
+
+## quantileExactExclusive {#quantileexactexclusive}
+
+Exactly computes the [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+To get exact value, all the passed values ​​are combined into an array, which is then partially sorted. Therefore, the function consumes `O(n)` memory, where `n` is a number of values that were passed. However, for a small number of values, the function is very effective.
+
+This function is equivalent to [PERCENTILE.EXC](https://support.microsoft.com/en-us/office/percentile-exc-function-bbaa7204-e9e1-4010-85bf-c31dc5dce4ba) Excel function, ([type R6](https://en.wikipedia.org/wiki/Quantile#Estimating_quantiles_from_a_sample)).
+
+When using multiple `quantileExactExclusive` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantilesExactExclusive](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantilesexactexclusive) function.
+
+**Syntax**
+
+``` sql
+quantileExactExclusive(level)(expr)
+```
+
+**Arguments**
+
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+
+**Parameters**
+
+-   `level` — Level of quantile. Optional. Possible values: (0, 1) — bounds not included. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median). [Float](../../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   Quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE num AS numbers(1000);
+
+SELECT quantileExactExclusive(0.6)(x) FROM (SELECT number AS x FROM num);
+```
+
+Result:
+
+``` text
+┌─quantileExactExclusive(0.6)(x)─┐
+│                          599.6 │
+└────────────────────────────────┘
+```
+
+## quantileExactInclusive {#quantileexactinclusive}
+
+Exactly computes the [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+To get exact value, all the passed values ​​are combined into an array, which is then partially sorted. Therefore, the function consumes `O(n)` memory, where `n` is a number of values that were passed. However, for a small number of values, the function is very effective.
+
+This function is equivalent to [PERCENTILE.INC](https://support.microsoft.com/en-us/office/percentile-inc-function-680f9539-45eb-410b-9a5e-c1355e5fe2ed) Excel function, ([type R7](https://en.wikipedia.org/wiki/Quantile#Estimating_quantiles_from_a_sample)).
+
+When using multiple `quantileExactInclusive` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantilesExactInclusive](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantilesexactinclusive) function.
+
+**Syntax**
+
+``` sql
+quantileExactInclusive(level)(expr)
+```
+
+**Arguments**
+
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+
+**Parameters**
+
+-   `level` — Level of quantile. Optional. Possible values: [0, 1] — bounds included. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median). [Float](../../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   Quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE num AS numbers(1000);
+
+SELECT quantileExactInclusive(0.6)(x) FROM (SELECT number AS x FROM num);
+```
+
+Result:
+
+``` text
+┌─quantileExactInclusive(0.6)(x)─┐
+│                          599.4 │
+└────────────────────────────────┘
+```
+
+**See Also**
+
+-   [median](../../../sql-reference/aggregate-functions/reference/median.md#median)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantileexactweighted.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantileexactweighted.md
new file mode 100644
index 00000000000..4740d4a26f8
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantileexactweighted.md
@@ -0,0 +1,67 @@
+---
+sidebar_position: 203
+---
+
+# quantileExactWeighted {#quantileexactweighted}
+
+Exactly computes the [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence, taking into account the weight of each element.
+
+To get exact value, all the passed values ​​are combined into an array, which is then partially sorted. Each value is counted with its weight, as if it is present `weight` times. A hash table is used in the algorithm. Because of this, if the passed values ​​are frequently repeated, the function consumes less RAM than [quantileExact](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexact). You can use this function instead of `quantileExact` and specify the weight 1.
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+**Syntax**
+
+``` sql
+quantileExactWeighted(level)(expr, weight)
+```
+
+Alias: `medianExactWeighted`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+-   `weight` — Column with weights of sequence members. Weight is a number of value occurrences.
+
+**Returned value**
+
+-   Quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Input table:
+
+``` text
+┌─n─┬─val─┐
+│ 0 │   3 │
+│ 1 │   2 │
+│ 2 │   1 │
+│ 5 │   4 │
+└───┴─────┘
+```
+
+Query:
+
+``` sql
+SELECT quantileExactWeighted(n, val) FROM t
+```
+
+Result:
+
+``` text
+┌─quantileExactWeighted(n, val)─┐
+│                             1 │
+└───────────────────────────────┘
+```
+
+**See Also**
+
+-   [median](../../../sql-reference/aggregate-functions/reference/median.md#median)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantiles.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiles.md
new file mode 100644
index 00000000000..6d0cf37f25e
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiles.md
@@ -0,0 +1,115 @@
+---
+sidebar_position: 201
+---
+
+# quantiles Functions {#quantiles-functions}
+
+## quantiles {#quantiles}
+
+Syntax: `quantiles(level1, level2, …)(x)`
+
+All the quantile functions also have corresponding quantiles functions: `quantiles`, `quantilesDeterministic`, `quantilesTiming`, `quantilesTimingWeighted`, `quantilesExact`, `quantilesExactWeighted`, `quantilesTDigest`, `quantilesBFloat16`. These functions calculate all the quantiles of the listed levels in one pass, and return an array of the resulting values.
+
+## quantilesExactExclusive {#quantilesexactexclusive}
+
+Exactly computes the [quantiles](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+To get exact value, all the passed values ​​are combined into an array, which is then partially sorted. Therefore, the function consumes `O(n)` memory, where `n` is a number of values that were passed. However, for a small number of values, the function is very effective.
+
+This function is equivalent to [PERCENTILE.EXC](https://support.microsoft.com/en-us/office/percentile-exc-function-bbaa7204-e9e1-4010-85bf-c31dc5dce4ba) Excel function, ([type R6](https://en.wikipedia.org/wiki/Quantile#Estimating_quantiles_from_a_sample)).
+
+Works more efficiently with sets of levels than [quantileExactExclusive](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexactexclusive).
+
+**Syntax**
+
+``` sql
+quantilesExactExclusive(level1, level2, ...)(expr)
+```
+
+**Arguments**
+
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+
+**Parameters**
+
+-   `level` — Levels of quantiles. Possible values: (0, 1) — bounds not included. [Float](../../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   [Array](../../../sql-reference/data-types/array.md) of quantiles of the specified levels.
+
+Type of array values:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE num AS numbers(1000);
+
+SELECT quantilesExactExclusive(0.25, 0.5, 0.75, 0.9, 0.95, 0.99, 0.999)(x) FROM (SELECT number AS x FROM num);
+```
+
+Result:
+
+``` text
+┌─quantilesExactExclusive(0.25, 0.5, 0.75, 0.9, 0.95, 0.99, 0.999)(x)─┐
+│ [249.25,499.5,749.75,899.9,949.9499999999999,989.99,998.999]        │
+└─────────────────────────────────────────────────────────────────────┘
+```
+
+## quantilesExactInclusive {#quantilesexactinclusive}
+
+Exactly computes the [quantiles](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+To get exact value, all the passed values ​​are combined into an array, which is then partially sorted. Therefore, the function consumes `O(n)` memory, where `n` is a number of values that were passed. However, for a small number of values, the function is very effective.
+
+This function is equivalent to [PERCENTILE.INC](https://support.microsoft.com/en-us/office/percentile-inc-function-680f9539-45eb-410b-9a5e-c1355e5fe2ed) Excel function, ([type R7](https://en.wikipedia.org/wiki/Quantile#Estimating_quantiles_from_a_sample)).
+
+Works more efficiently with sets of levels than [quantileExactInclusive](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexactinclusive).
+
+**Syntax**
+
+``` sql
+quantilesExactInclusive(level1, level2, ...)(expr)
+```
+
+**Arguments**
+
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+
+**Parameters**
+
+-   `level` — Levels of quantiles. Possible values: [0, 1] — bounds included. [Float](../../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   [Array](../../../sql-reference/data-types/array.md) of quantiles of the specified levels.
+
+Type of array values:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE num AS numbers(1000);
+
+SELECT quantilesExactInclusive(0.25, 0.5, 0.75, 0.9, 0.95, 0.99, 0.999)(x) FROM (SELECT number AS x FROM num);
+```
+
+Result:
+
+``` text
+┌─quantilesExactInclusive(0.25, 0.5, 0.75, 0.9, 0.95, 0.99, 0.999)(x)─┐
+│ [249.75,499.5,749.25,899.1,949.05,989.01,998.001]                   │
+└─────────────────────────────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletdigest.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletdigest.md
new file mode 100644
index 00000000000..f42c88b2aca
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletdigest.md
@@ -0,0 +1,57 @@
+---
+sidebar_position: 207
+---
+
+# quantileTDigest {#quantiletdigest}
+
+Computes an approximate [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence using the [t-digest](https://github.com/tdunning/t-digest/blob/master/docs/t-digest-paper/histo.pdf) algorithm.
+
+Memory consumption is `log(n)`, where `n` is a number of values. The result depends on the order of running the query, and is nondeterministic.
+
+The performance of the function is lower than performance of [quantile](../../../sql-reference/aggregate-functions/reference/quantile.md#quantile) or [quantileTiming](../../../sql-reference/aggregate-functions/reference/quantiletiming.md#quantiletiming). In terms of the ratio of State size to precision, this function is much better than `quantile`.
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+**Syntax**
+
+``` sql
+quantileTDigest(level)(expr)
+```
+
+Alias: `medianTDigest`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+-   Approximate quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT quantileTDigest(number) FROM numbers(10)
+```
+
+Result:
+
+``` text
+┌─quantileTDigest(number)─┐
+│                     4.5 │
+└─────────────────────────┘
+```
+
+**See Also**
+
+-   [median](../../../sql-reference/aggregate-functions/reference/median.md#median)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletdigestweighted.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletdigestweighted.md
new file mode 100644
index 00000000000..684e438f0c7
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletdigestweighted.md
@@ -0,0 +1,62 @@
+---
+sidebar_position: 208
+---
+
+# quantileTDigestWeighted {#quantiletdigestweighted}
+
+Computes an approximate [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence using the [t-digest](https://github.com/tdunning/t-digest/blob/master/docs/t-digest-paper/histo.pdf) algorithm. The function takes into account the weight of each sequence member. The maximum error is 1%. Memory consumption is `log(n)`, where `n` is a number of values.
+
+The performance of the function is lower than performance of [quantile](../../../sql-reference/aggregate-functions/reference/quantile.md#quantile) or [quantileTiming](../../../sql-reference/aggregate-functions/reference/quantiletiming.md#quantiletiming). In terms of the ratio of State size to precision, this function is much better than `quantile`.
+
+The result depends on the order of running the query, and is nondeterministic.
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+:::note    
+Using `quantileTDigestWeighted` [is not recommended for tiny data sets](https://github.com/tdunning/t-digest/issues/167#issuecomment-828650275) and can lead to significat error. In this case, consider possibility of using [`quantileTDigest`](../../../sql-reference/aggregate-functions/reference/quantiletdigest.md) instead.
+:::
+
+**Syntax**
+
+``` sql
+quantileTDigestWeighted(level)(expr, weight)
+```
+
+Alias: `medianTDigestWeighted`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+-   `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md).
+-   `weight` — Column with weights of sequence elements. Weight is a number of value occurrences.
+
+**Returned value**
+
+-   Approximate quantile of the specified level.
+
+Type:
+
+-   [Float64](../../../sql-reference/data-types/float.md) for numeric data type input.
+-   [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type.
+-   [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT quantileTDigestWeighted(number, 1) FROM numbers(10)
+```
+
+Result:
+
+``` text
+┌─quantileTDigestWeighted(number, 1)─┐
+│                                4.5 │
+└────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [median](../../../sql-reference/aggregate-functions/reference/median.md#median)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletiming.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletiming.md
new file mode 100644
index 00000000000..f282f7e2004
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletiming.md
@@ -0,0 +1,88 @@
+---
+sidebar_position: 204
+---
+
+# quantileTiming {#quantiletiming}
+
+With the determined precision computes the [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence.
+
+The result is deterministic (it does not depend on the query processing order). The function is optimized for working with sequences which describe distributions like loading web pages times or backend response times.
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+**Syntax**
+
+``` sql
+quantileTiming(level)(expr)
+```
+
+Alias: `medianTiming`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+
+-   `expr` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) over a column values returning a [Float\*](../../../sql-reference/data-types/float.md)-type number.
+
+    -   If negative values are passed to the function, the behavior is undefined.
+    -   If the value is greater than 30,000 (a page loading time of more than 30 seconds), it is assumed to be 30,000.
+
+**Accuracy**
+
+The calculation is accurate if:
+
+-   Total number of values does not exceed 5670.
+-   Total number of values exceeds 5670, but the page loading time is less than 1024ms.
+
+Otherwise, the result of the calculation is rounded to the nearest multiple of 16 ms.
+
+:::note    
+For calculating page loading time quantiles, this function is more effective and accurate than [quantile](../../../sql-reference/aggregate-functions/reference/quantile.md#quantile).
+:::
+
+**Returned value**
+
+-   Quantile of the specified level.
+
+Type: `Float32`.
+
+:::note    
+If no values are passed to the function (when using `quantileTimingIf`), [NaN](../../../sql-reference/data-types/float.md#data_type-float-nan-inf) is returned. The purpose of this is to differentiate these cases from cases that result in zero. See [ORDER BY clause](../../../sql-reference/statements/select/order-by.md#select-order-by) for notes on sorting `NaN` values.
+:::
+
+**Example**
+
+Input table:
+
+``` text
+┌─response_time─┐
+│            72 │
+│           112 │
+│           126 │
+│           145 │
+│           104 │
+│           242 │
+│           313 │
+│           168 │
+│           108 │
+└───────────────┘
+```
+
+Query:
+
+``` sql
+SELECT quantileTiming(response_time) FROM t
+```
+
+Result:
+
+``` text
+┌─quantileTiming(response_time)─┐
+│                           126 │
+└───────────────────────────────┘
+```
+
+**See Also**
+
+-   [median](../../../sql-reference/aggregate-functions/reference/median.md#median)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletimingweighted.md b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletimingweighted.md
new file mode 100644
index 00000000000..c773f900764
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/quantiletimingweighted.md
@@ -0,0 +1,121 @@
+---
+sidebar_position: 205
+---
+
+# quantileTimingWeighted {#quantiletimingweighted}
+
+With the determined precision computes the [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence according to the weight of each sequence member.
+
+The result is deterministic (it does not depend on the query processing order). The function is optimized for working with sequences which describe distributions like loading web pages times or backend response times.
+
+When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function.
+
+**Syntax**
+
+``` sql
+quantileTimingWeighted(level)(expr, weight)
+```
+
+Alias: `medianTimingWeighted`.
+
+**Arguments**
+
+-   `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median).
+
+-   `expr` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) over a column values returning a [Float\*](../../../sql-reference/data-types/float.md)-type number.
+
+        - If negative values are passed to the function, the behavior is undefined.
+        - If the value is greater than 30,000 (a page loading time of more than 30 seconds), it is assumed to be 30,000.
+
+-   `weight` — Column with weights of sequence elements. Weight is a number of value occurrences.
+
+**Accuracy**
+
+The calculation is accurate if:
+
+-   Total number of values does not exceed 5670.
+-   Total number of values exceeds 5670, but the page loading time is less than 1024ms.
+
+Otherwise, the result of the calculation is rounded to the nearest multiple of 16 ms.
+
+:::note    
+For calculating page loading time quantiles, this function is more effective and accurate than [quantile](../../../sql-reference/aggregate-functions/reference/quantile.md#quantile).
+:::
+
+**Returned value**
+
+-   Quantile of the specified level.
+
+Type: `Float32`.
+
+:::note    
+If no values are passed to the function (when using `quantileTimingIf`), [NaN](../../../sql-reference/data-types/float.md#data_type-float-nan-inf) is returned. The purpose of this is to differentiate these cases from cases that result in zero. See [ORDER BY clause](../../../sql-reference/statements/select/order-by.md#select-order-by) for notes on sorting `NaN` values.
+:::
+
+**Example**
+
+Input table:
+
+``` text
+┌─response_time─┬─weight─┐
+│            68 │      1 │
+│           104 │      2 │
+│           112 │      3 │
+│           126 │      2 │
+│           138 │      1 │
+│           162 │      1 │
+└───────────────┴────────┘
+```
+
+Query:
+
+``` sql
+SELECT quantileTimingWeighted(response_time, weight) FROM t
+```
+
+Result:
+
+``` text
+┌─quantileTimingWeighted(response_time, weight)─┐
+│                                           112 │
+└───────────────────────────────────────────────┘
+```
+
+# quantilesTimingWeighted {#quantilestimingweighted}
+
+Same as `quantileTimingWeighted`, but accept multiple parameters with quantile levels and return an Array filled with many values of that quantiles.
+
+
+**Example**
+
+Input table:
+
+``` text
+┌─response_time─┬─weight─┐
+│            68 │      1 │
+│           104 │      2 │
+│           112 │      3 │
+│           126 │      2 │
+│           138 │      1 │
+│           162 │      1 │
+└───────────────┴────────┘
+```
+
+Query:
+
+``` sql
+SELECT quantilesTimingWeighted(0,5, 0.99)(response_time, weight) FROM t
+```
+
+Result:
+
+``` text
+┌─quantilesTimingWeighted(0.5, 0.99)(response_time, weight)─┐
+│ [112,162]                                                 │
+└───────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [median](../../../sql-reference/aggregate-functions/reference/median.md#median)
+-   [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/rankCorr.md b/docs/en/reference/sql-reference/aggregate-functions/reference/rankCorr.md
new file mode 100644
index 00000000000..399fd88cf0e
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/rankCorr.md
@@ -0,0 +1,57 @@
+---
+sidebar_position: 145
+---
+
+# rankCorr {#agg_function-rankcorr}
+
+Computes a rank correlation coefficient.
+
+**Syntax**
+
+``` sql
+rankCorr(x, y)
+```
+
+**Arguments**
+
+-   `x` — Arbitrary value. [Float32](../../../sql-reference/data-types/float.md#float32-float64) or [Float64](../../../sql-reference/data-types/float.md#float32-float64).
+-   `y` — Arbitrary value. [Float32](../../../sql-reference/data-types/float.md#float32-float64) or [Float64](../../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value(s)**
+
+-   Returns a rank correlation coefficient of the ranks of x and y. The value of the correlation coefficient ranges from -1 to +1. If less than two arguments are passed, the function will return an exception. The value close to +1 denotes a high linear relationship, and with an increase of one random variable, the second random variable also increases. The value close to -1 denotes a high linear relationship, and with an increase of one random variable, the second random variable decreases. The value close or equal to 0 denotes no relationship between the two random variables.
+
+Type: [Float64](../../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT rankCorr(number, number) FROM numbers(100);
+```
+
+Result:
+
+``` text
+┌─rankCorr(number, number)─┐
+│                        1 │
+└──────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT roundBankers(rankCorr(exp(number), sin(number)), 3) FROM numbers(100);
+```
+
+Result:
+
+``` text
+┌─roundBankers(rankCorr(exp(number), sin(number)), 3)─┐
+│                                              -0.037 │
+└─────────────────────────────────────────────────────┘
+```
+**See Also**
+
+-   [Spearman's rank correlation coefficient](https://en.wikipedia.org/wiki/Spearman%27s_rank_correlation_coefficient)
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/simplelinearregression.md b/docs/en/reference/sql-reference/aggregate-functions/reference/simplelinearregression.md
new file mode 100644
index 00000000000..8684cd4c3bb
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/simplelinearregression.md
@@ -0,0 +1,42 @@
+---
+sidebar_position: 220
+---
+
+# simpleLinearRegression {#simplelinearregression}
+
+Performs simple (unidimensional) linear regression.
+
+``` sql
+simpleLinearRegression(x, y)
+```
+
+Parameters:
+
+-   `x` — Column with dependent variable values.
+-   `y` — Column with explanatory variable values.
+
+Returned values:
+
+Constants `(a, b)` of the resulting line `y = a*x + b`.
+
+**Examples**
+
+``` sql
+SELECT arrayReduce('simpleLinearRegression', [0, 1, 2, 3], [0, 1, 2, 3])
+```
+
+``` text
+┌─arrayReduce('simpleLinearRegression', [0, 1, 2, 3], [0, 1, 2, 3])─┐
+│ (1,0)                                                             │
+└───────────────────────────────────────────────────────────────────┘
+```
+
+``` sql
+SELECT arrayReduce('simpleLinearRegression', [0, 1, 2, 3], [3, 4, 5, 6])
+```
+
+``` text
+┌─arrayReduce('simpleLinearRegression', [0, 1, 2, 3], [3, 4, 5, 6])─┐
+│ (1,3)                                                             │
+└───────────────────────────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/skewpop.md b/docs/en/reference/sql-reference/aggregate-functions/reference/skewpop.md
new file mode 100644
index 00000000000..4cb3d58304f
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/skewpop.md
@@ -0,0 +1,25 @@
+---
+sidebar_position: 150
+---
+
+# skewPop {#skewpop}
+
+Computes the [skewness](https://en.wikipedia.org/wiki/Skewness) of a sequence.
+
+``` sql
+skewPop(expr)
+```
+
+**Arguments**
+
+`expr` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) returning a number.
+
+**Returned value**
+
+The skewness of the given distribution. Type — [Float64](../../../sql-reference/data-types/float.md)
+
+**Example**
+
+``` sql
+SELECT skewPop(value) FROM series_with_value_column;
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/skewsamp.md b/docs/en/reference/sql-reference/aggregate-functions/reference/skewsamp.md
new file mode 100644
index 00000000000..92e807d2d7d
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/skewsamp.md
@@ -0,0 +1,27 @@
+---
+sidebar_position: 151
+---
+
+# skewSamp {#skewsamp}
+
+Computes the [sample skewness](https://en.wikipedia.org/wiki/Skewness) of a sequence.
+
+It represents an unbiased estimate of the skewness of a random variable if passed values form its sample.
+
+``` sql
+skewSamp(expr)
+```
+
+**Arguments**
+
+`expr` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) returning a number.
+
+**Returned value**
+
+The skewness of the given distribution. Type — [Float64](../../../sql-reference/data-types/float.md). If `n <= 1` (`n` is the size of the sample), then the function returns `nan`.
+
+**Example**
+
+``` sql
+SELECT skewSamp(value) FROM series_with_value_column;
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/sparkbar.md b/docs/en/reference/sql-reference/aggregate-functions/reference/sparkbar.md
new file mode 100644
index 00000000000..ebb9cccbd40
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/sparkbar.md
@@ -0,0 +1,64 @@
+---
+sidebar_position: 311
+sidebar_label: sparkbar
+---
+
+# sparkbar {#sparkbar}
+
+The function plots a frequency histogram for values `x` and the repetition rate `y` of these values over the interval `[min_x, max_x]`.
+
+
+If no interval is specified, then the minimum `x` is used as the interval start, and the maximum `x` — as the interval end. 
+
+**Syntax**
+
+``` sql
+sparkbar(width[, min_x, max_x])(x, y)
+```
+
+**Parameters**
+
+-   `width` — The number of segments. Type: [Integer](../../../sql-reference/data-types/int-uint.md).
+-   `min_x` — The interval start. Optional parameter.
+-   `max_x` — The interval end. Optional parameter.
+
+**Arguments**
+
+-   `x` — The field with values.
+-   `y` — The field with the frequency of values.
+
+**Returned value**
+
+-   The frequency histogram.
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE spark_bar_data (`cnt` UInt64,`event_date` Date) ENGINE = MergeTree ORDER BY event_date SETTINGS index_granularity = 8192;
+ 
+INSERT INTO spark_bar_data VALUES(1,'2020-01-01'),(4,'2020-01-02'),(5,'2020-01-03'),(2,'2020-01-04'),(3,'2020-01-05'),(7,'2020-01-06'),(6,'2020-01-07'),(8,'2020-01-08'),(2,'2020-01-11');
+
+SELECT sparkbar(9)(event_date,cnt) FROM spark_bar_data;
+
+SELECT sparkbar(9,toDate('2020-01-01'),toDate('2020-01-10'))(event_date,cnt) FROM spark_bar_data;
+```
+
+Result:
+
+``` text
+
+┌─sparkbar(9)(event_date, cnt)─┐
+│                              │
+│ ▁▅▄▃██▅ ▁                   │
+│                              │
+└──────────────────────────────┘
+
+┌─sparkbar(9, toDate('2020-01-01'), toDate('2020-01-10'))(event_date, cnt)─┐
+│                                                                          │
+│▁▄▄▂▅▇█▁                                                                 │
+│                                                                          │
+└──────────────────────────────────────────────────────────────────────────┘
+```
+
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/stddevpop.md b/docs/en/reference/sql-reference/aggregate-functions/reference/stddevpop.md
new file mode 100644
index 00000000000..2b22320ae7a
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/stddevpop.md
@@ -0,0 +1,11 @@
+---
+sidebar_position: 30
+---
+
+# stddevPop {#stddevpop}
+
+The result is equal to the square root of [varPop](../../../sql-reference/aggregate-functions/reference/varpop.md).
+
+:::note    
+This function uses a numerically unstable algorithm. If you need [numerical stability](https://en.wikipedia.org/wiki/Numerical_stability) in calculations, use the `stddevPopStable` function. It works slower but provides a lower computational error.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/stddevsamp.md b/docs/en/reference/sql-reference/aggregate-functions/reference/stddevsamp.md
new file mode 100644
index 00000000000..3dcee821606
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/stddevsamp.md
@@ -0,0 +1,11 @@
+---
+sidebar_position: 31
+---
+
+# stddevSamp {#stddevsamp}
+
+The result is equal to the square root of [varSamp](../../../sql-reference/aggregate-functions/reference/varsamp.md).
+
+:::note    
+This function uses a numerically unstable algorithm. If you need [numerical stability](https://en.wikipedia.org/wiki/Numerical_stability) in calculations, use the `stddevSampStable` function. It works slower but provides a lower computational error.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/stochasticlinearregression.md b/docs/en/reference/sql-reference/aggregate-functions/reference/stochasticlinearregression.md
new file mode 100644
index 00000000000..e171629e90d
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/stochasticlinearregression.md
@@ -0,0 +1,75 @@
+---
+sidebar_position: 221
+---
+
+# stochasticLinearRegression {#agg_functions-stochasticlinearregression}
+
+This function implements stochastic linear regression. It supports custom parameters for learning rate, L2 regularization coefficient, mini-batch size and has few methods for updating weights ([Adam](https://en.wikipedia.org/wiki/Stochastic_gradient_descent#Adam) (used by default), [simple SGD](https://en.wikipedia.org/wiki/Stochastic_gradient_descent), [Momentum](https://en.wikipedia.org/wiki/Stochastic_gradient_descent#Momentum), [Nesterov](https://mipt.ru/upload/medialibrary/d7e/41-91.pdf)).
+
+### Parameters {#agg_functions-stochasticlinearregression-parameters}
+
+There are 4 customizable parameters. They are passed to the function sequentially, but there is no need to pass all four - default values will be used, however good model required some parameter tuning.
+
+``` text
+stochasticLinearRegression(1.0, 1.0, 10, 'SGD')
+```
+
+1.  `learning rate` is the coefficient on step length, when gradient descent step is performed. Too big learning rate may cause infinite weights of the model. Default is `0.00001`.
+2.  `l2 regularization coefficient` which may help to prevent overfitting. Default is `0.1`.
+3.  `mini-batch size` sets the number of elements, which gradients will be computed and summed to perform one step of gradient descent. Pure stochastic descent uses one element, however having small batches(about 10 elements) make gradient steps more stable. Default is `15`.
+4.  `method for updating weights`, they are: `Adam` (by default), `SGD`, `Momentum`, `Nesterov`. `Momentum` and `Nesterov` require little bit more computations and memory, however they happen to be useful in terms of speed of convergance and stability of stochastic gradient methods.
+
+### Usage {#agg_functions-stochasticlinearregression-usage}
+
+`stochasticLinearRegression` is used in two steps: fitting the model and predicting on new data. In order to fit the model and save its state for later usage we use `-State` combinator, which basically saves the state (model weights, etc).
+To predict we use function [evalMLMethod](../../../sql-reference/functions/machine-learning-functions.md#machine_learning_methods-evalmlmethod), which takes a state as an argument as well as features to predict on.
+
+<a name="stochasticlinearregression-usage-fitting"></a>
+
+**1.** Fitting
+
+Such query may be used.
+
+``` sql
+CREATE TABLE IF NOT EXISTS train_data
+(
+    param1 Float64,
+    param2 Float64,
+    target Float64
+) ENGINE = Memory;
+
+CREATE TABLE your_model ENGINE = Memory AS SELECT
+stochasticLinearRegressionState(0.1, 0.0, 5, 'SGD')(target, param1, param2)
+AS state FROM train_data;
+```
+
+Here we also need to insert data into `train_data` table. The number of parameters is not fixed, it depends only on number of arguments, passed into `linearRegressionState`. They all must be numeric values.
+Note that the column with target value(which we would like to learn to predict) is inserted as the first argument.
+
+**2.** Predicting
+
+After saving a state into the table, we may use it multiple times for prediction, or even merge with other states and create new even better models.
+
+``` sql
+WITH (SELECT state FROM your_model) AS model SELECT
+evalMLMethod(model, param1, param2) FROM test_data
+```
+
+The query will return a column of predicted values. Note that first argument of `evalMLMethod` is `AggregateFunctionState` object, next are columns of features.
+
+`test_data` is a table like `train_data` but may not contain target value.
+
+### Notes {#agg_functions-stochasticlinearregression-notes}
+
+1.  To merge two models user may create such query:
+    `sql  SELECT state1 + state2 FROM your_models`
+    where `your_models` table contains both models. This query will return new `AggregateFunctionState` object.
+
+2.  User may fetch weights of the created model for its own purposes without saving the model if no `-State` combinator is used.
+    `sql  SELECT stochasticLinearRegression(0.01)(target, param1, param2) FROM train_data`
+    Such query will fit the model and return its weights - first are weights, which correspond to the parameters of the model, the last one is bias. So in the example above the query will return a column with 3 values.
+
+**See Also**
+
+-   [stochasticLogisticRegression](../../../sql-reference/aggregate-functions/reference/stochasticlogisticregression.md#agg_functions-stochasticlogisticregression)
+-   [Difference between linear and logistic regressions](https://stackoverflow.com/questions/12146914/what-is-the-difference-between-linear-regression-and-logistic-regression)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/stochasticlogisticregression.md b/docs/en/reference/sql-reference/aggregate-functions/reference/stochasticlogisticregression.md
new file mode 100644
index 00000000000..a7d4c640126
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/stochasticlogisticregression.md
@@ -0,0 +1,55 @@
+---
+sidebar_position: 222
+---
+
+# stochasticLogisticRegression {#agg_functions-stochasticlogisticregression}
+
+This function implements stochastic logistic regression. It can be used for binary classification problem, supports the same custom parameters as stochasticLinearRegression and works the same way.
+
+### Parameters {#agg_functions-stochasticlogisticregression-parameters}
+
+Parameters are exactly the same as in stochasticLinearRegression:
+`learning rate`, `l2 regularization coefficient`, `mini-batch size`, `method for updating weights`.
+For more information see [parameters](#agg_functions-stochasticlinearregression-parameters).
+
+``` text
+stochasticLogisticRegression(1.0, 1.0, 10, 'SGD')
+```
+
+**1.** Fitting
+
+<!-- -->
+
+    See the `Fitting` section in the [stochasticLinearRegression](#stochasticlinearregression-usage-fitting) description.
+
+    Predicted labels have to be in \[-1, 1\].
+
+**2.** Predicting
+
+<!-- -->
+
+    Using saved state we can predict probability of object having label `1`.
+
+    ``` sql
+    WITH (SELECT state FROM your_model) AS model SELECT
+    evalMLMethod(model, param1, param2) FROM test_data
+    ```
+
+    The query will return a column of probabilities. Note that first argument of `evalMLMethod` is `AggregateFunctionState` object, next are columns of features.
+
+    We can also set a bound of probability, which assigns elements to different labels.
+
+    ``` sql
+    SELECT ans < 1.1 AND ans > 0.5 FROM
+    (WITH (SELECT state FROM your_model) AS model SELECT
+    evalMLMethod(model, param1, param2) AS ans FROM test_data)
+    ```
+
+    Then the result will be labels.
+
+    `test_data` is a table like `train_data` but may not contain target value.
+
+**See Also**
+
+-   [stochasticLinearRegression](../../../sql-reference/aggregate-functions/reference/stochasticlinearregression.md#agg_functions-stochasticlinearregression)
+-   [Difference between linear and logistic regressions.](https://stackoverflow.com/questions/12146914/what-is-the-difference-between-linear-regression-and-logistic-regression)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/studentttest.md b/docs/en/reference/sql-reference/aggregate-functions/reference/studentttest.md
new file mode 100644
index 00000000000..86207a35c04
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/studentttest.md
@@ -0,0 +1,73 @@
+---
+sidebar_position: 300
+sidebar_label: studentTTest
+---
+
+# studentTTest {#studentttest}
+
+Applies Student's t-test to samples from two populations.
+
+**Syntax**
+
+``` sql
+studentTTest([confidence_level])(sample_data, sample_index)
+```
+
+Values of both samples are in the `sample_data` column. If `sample_index` equals to 0 then the value in that row belongs to the sample from the first population. Otherwise it belongs to the sample from the second population.
+The null hypothesis is that means of populations are equal. Normal distribution with equal variances is assumed.
+
+**Arguments**
+
+-   `sample_data` — Sample data. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
+-   `sample_index` — Sample index. [Integer](../../../sql-reference/data-types/int-uint.md).
+
+**Parameters**
+
+-   `confidence_level` — Confidence level in order to calculate confidence intervals. [Float](../../../sql-reference/data-types/float.md).
+
+
+**Returned values**
+
+[Tuple](../../../sql-reference/data-types/tuple.md) with two or four elements (if the optional `confidence_level` is specified):
+
+-   calculated t-statistic. [Float64](../../../sql-reference/data-types/float.md).
+-   calculated p-value. [Float64](../../../sql-reference/data-types/float.md).
+-   [calculated confidence-interval-low.] [Float64](../../../sql-reference/data-types/float.md).
+-   [calculated confidence-interval-high.] [Float64](../../../sql-reference/data-types/float.md).
+
+
+**Example**
+
+Input table:
+
+``` text
+┌─sample_data─┬─sample_index─┐
+│        20.3 │            0 │
+│        21.1 │            0 │
+│        21.9 │            1 │
+│        21.7 │            0 │
+│        19.9 │            1 │
+│        21.8 │            1 │
+└─────────────┴──────────────┘
+```
+
+Query:
+
+``` sql
+SELECT studentTTest(sample_data, sample_index) FROM student_ttest;
+```
+
+Result:
+
+``` text
+┌─studentTTest(sample_data, sample_index)───┐
+│ (-0.21739130434783777,0.8385421208415731) │
+└───────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [Student's t-test](https://en.wikipedia.org/wiki/Student%27s_t-test)
+-   [welchTTest function](welchttest.md#welchttest)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/aggregate-functions/reference/studentttest/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/sum.md b/docs/en/reference/sql-reference/aggregate-functions/reference/sum.md
new file mode 100644
index 00000000000..b72cb84e74f
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/sum.md
@@ -0,0 +1,7 @@
+---
+sidebar_position: 4
+---
+
+# sum {#agg_function-sum}
+
+Calculates the sum. Only works for numbers.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/sumcount.md b/docs/en/reference/sql-reference/aggregate-functions/reference/sumcount.md
new file mode 100644
index 00000000000..dbc0601241e
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/sumcount.md
@@ -0,0 +1,46 @@
+---
+sidebar_position: 144
+---
+
+# sumCount {#agg_function-sumCount}
+
+Calculates the sum of the numbers and counts the number of rows at the same time. The function is used by ClickHouse query optimizer: if there are multiple `sum`, `count` or `avg` functions in a query, they can be replaced to single `sumCount` function to reuse the calculations. The function is rarely needed to use explicitly.
+
+**Syntax**
+
+``` sql
+sumCount(x)
+```
+
+**Arguments**
+
+-   `x` — Input value, must be [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md), or [Decimal](../../../sql-reference/data-types/decimal.md).
+
+**Returned value**
+
+-   Tuple `(sum, count)`, where `sum` is the sum of numbers and `count` is the number of rows with not-NULL values.
+
+Type: [Tuple](../../../sql-reference/data-types/tuple.md).
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE s_table (x Int8) Engine = Log;
+INSERT INTO s_table SELECT number FROM numbers(0, 20);
+INSERT INTO s_table VALUES (NULL);
+SELECT sumCount(x) from s_table;
+```
+
+Result:
+
+``` text
+┌─sumCount(x)─┐
+│ (190,20)    │
+└─────────────┘
+```
+
+**See also**
+
+- [optimize_syntax_fuse_functions](../../../operations/settings/settings.md#optimize_syntax_fuse_functions) setting.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/sumkahan.md b/docs/en/reference/sql-reference/aggregate-functions/reference/sumkahan.md
new file mode 100644
index 00000000000..8c96464dfd5
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/sumkahan.md
@@ -0,0 +1,40 @@
+---
+sidebar_position: 145
+---
+
+# sumKahan {#agg_function-sumKahan}
+
+Calculates the sum of the numbers with [Kahan compensated summation algorithm](https://en.wikipedia.org/wiki/Kahan_summation_algorithm)
+Slower than [sum](./sum.md) function.
+The compensation works only for [Float](../../../sql-reference/data-types/float.md) types.
+
+
+**Syntax**
+
+``` sql
+sumKahan(x)
+```
+
+**Arguments**
+
+-   `x` — Input value, must be [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md), or [Decimal](../../../sql-reference/data-types/decimal.md).
+
+**Returned value**
+
+-  the sum of numbers, with type [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md), or [Decimal](../../../sql-reference/data-types/decimal.md) depends on type of input arguments
+
+**Example**
+
+Query:
+
+``` sql
+SELECT sum(0.1), sumKahan(0.1) FROM numbers(10);
+```
+
+Result:
+
+``` text
+┌───────────sum(0.1)─┬─sumKahan(0.1)─┐
+│ 0.9999999999999999 │             1 │
+└────────────────────┴───────────────┘
+```
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/summap.md b/docs/en/reference/sql-reference/aggregate-functions/reference/summap.md
new file mode 100644
index 00000000000..78ce6a9e835
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/summap.md
@@ -0,0 +1,48 @@
+---
+sidebar_position: 141
+---
+
+# sumMap {#agg_functions-summap}
+
+Syntax: `sumMap(key, value)` or `sumMap(Tuple(key, value))`
+
+Totals the `value` array according to the keys specified in the `key` array.
+
+Passing tuple of keys and values arrays is a synonym to passing two arrays of keys and values.
+
+The number of elements in `key` and `value` must be the same for each row that is totaled.
+
+Returns a tuple of two arrays: keys in sorted order, and values ​​summed for the corresponding keys.
+
+Example:
+
+``` sql
+CREATE TABLE sum_map(
+    date Date,
+    timeslot DateTime,
+    statusMap Nested(
+        status UInt16,
+        requests UInt64
+    ),
+    statusMapTuple Tuple(Array(Int32), Array(Int32))
+) ENGINE = Log;
+INSERT INTO sum_map VALUES
+    ('2000-01-01', '2000-01-01 00:00:00', [1, 2, 3], [10, 10, 10], ([1, 2, 3], [10, 10, 10])),
+    ('2000-01-01', '2000-01-01 00:00:00', [3, 4, 5], [10, 10, 10], ([3, 4, 5], [10, 10, 10])),
+    ('2000-01-01', '2000-01-01 00:01:00', [4, 5, 6], [10, 10, 10], ([4, 5, 6], [10, 10, 10])),
+    ('2000-01-01', '2000-01-01 00:01:00', [6, 7, 8], [10, 10, 10], ([6, 7, 8], [10, 10, 10]));
+
+SELECT
+    timeslot,
+    sumMap(statusMap.status, statusMap.requests),
+    sumMap(statusMapTuple)
+FROM sum_map
+GROUP BY timeslot
+```
+
+``` text
+┌────────────timeslot─┬─sumMap(statusMap.status, statusMap.requests)─┬─sumMap(statusMapTuple)─────────┐
+│ 2000-01-01 00:00:00 │ ([1,2,3,4,5],[10,10,20,10,10])               │ ([1,2,3,4,5],[10,10,20,10,10]) │
+│ 2000-01-01 00:01:00 │ ([4,5,6,7,8],[10,10,20,10,10])               │ ([4,5,6,7,8],[10,10,20,10,10]) │
+└─────────────────────┴──────────────────────────────────────────────┴────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/sumwithoverflow.md b/docs/en/reference/sql-reference/aggregate-functions/reference/sumwithoverflow.md
new file mode 100644
index 00000000000..0582eb5fb7b
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/sumwithoverflow.md
@@ -0,0 +1,9 @@
+---
+sidebar_position: 140
+---
+
+# sumWithOverflow {#sumwithoverflowx}
+
+Computes the sum of the numbers, using the same data type for the result as for the input parameters. If the sum exceeds the maximum value for this data type, it is calculated with overflow.
+
+Only works for numbers.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/topk.md b/docs/en/reference/sql-reference/aggregate-functions/reference/topk.md
new file mode 100644
index 00000000000..d0f445c6710
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/topk.md
@@ -0,0 +1,42 @@
+---
+sidebar_position: 108
+---
+
+# topK {#topk}
+
+Returns an array of the approximately most frequent values in the specified column. The resulting array is sorted in descending order of approximate frequency of values (not by the values themselves).
+
+Implements the [Filtered Space-Saving](http://www.l2f.inesc-id.pt/~fmmb/wiki/uploads/Work/misnis.ref0a.pdf) algorithm for analyzing TopK, based on the reduce-and-combine algorithm from [Parallel Space Saving](https://arxiv.org/pdf/1401.0702.pdf).
+
+``` sql
+topK(N)(column)
+```
+
+This function does not provide a guaranteed result. In certain situations, errors might occur and it might return frequent values that aren’t the most frequent values.
+
+We recommend using the `N < 10` value; performance is reduced with large `N` values. Maximum value of `N = 65536`.
+
+**Arguments**
+
+-   `N` – The number of elements to return.
+
+If the parameter is omitted, default value 10 is used.
+
+**Arguments**
+
+-   `x` – The value to calculate frequency.
+
+**Example**
+
+Take the [OnTime](../../../example-datasets/ontime.md) data set and select the three most frequently occurring values in the `AirlineID` column.
+
+``` sql
+SELECT topK(3)(AirlineID) AS res
+FROM ontime
+```
+
+``` text
+┌─res─────────────────┐
+│ [19393,19790,19805] │
+└─────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/topkweighted.md b/docs/en/reference/sql-reference/aggregate-functions/reference/topkweighted.md
new file mode 100644
index 00000000000..2d6e86667ef
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/topkweighted.md
@@ -0,0 +1,43 @@
+---
+sidebar_position: 109
+---
+
+# topKWeighted {#topkweighted}
+
+Returns an array of the approximately most frequent values in the specified column. The resulting array is sorted in descending order of approximate frequency of values (not by the values themselves). Additionally, the weight of the value is taken into account.
+
+**Syntax**
+
+``` sql
+topKWeighted(N)(x, weight)
+```
+
+**Arguments**
+
+-   `N` — The number of elements to return.
+-   `x` — The value.
+-   `weight` — The weight. Every value is accounted `weight` times for frequency calculation. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+Returns an array of the values with maximum approximate sum of weights.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT topKWeighted(10)(number, number) FROM numbers(1000)
+```
+
+Result:
+
+``` text
+┌─topKWeighted(10)(number, number)──────────┐
+│ [999,998,997,996,995,994,993,992,991,990] │
+└───────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [topK](../../../sql-reference/aggregate-functions/reference/topk.md)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/uniq.md b/docs/en/reference/sql-reference/aggregate-functions/reference/uniq.md
new file mode 100644
index 00000000000..6e6791702ef
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/uniq.md
@@ -0,0 +1,39 @@
+---
+sidebar_position: 190
+---
+
+# uniq {#agg_function-uniq}
+
+Calculates the approximate number of different values of the argument.
+
+``` sql
+uniq(x[, ...])
+```
+
+**Arguments**
+
+The function takes a variable number of parameters. Parameters can be `Tuple`, `Array`, `Date`, `DateTime`, `String`, or numeric types.
+
+**Returned value**
+
+-   A [UInt64](../../../sql-reference/data-types/int-uint.md)-type number.
+
+**Implementation details**
+
+Function:
+
+-   Calculates a hash for all parameters in the aggregate, then uses it in calculations.
+
+-   Uses an adaptive sampling algorithm. For the calculation state, the function uses a sample of element hash values up to 65536. This algorithm is very accurate and very efficient on the CPU. When the query contains several of these functions, using `uniq` is almost as fast as using other aggregate functions.
+
+-   Provides the result deterministically (it does not depend on the query processing order).
+
+We recommend using this function in almost all scenarios.
+
+**See Also**
+
+-   [uniqCombined](../../../sql-reference/aggregate-functions/reference/uniqcombined.md#agg_function-uniqcombined)
+-   [uniqCombined64](../../../sql-reference/aggregate-functions/reference/uniqcombined64.md#agg_function-uniqcombined64)
+-   [uniqHLL12](../../../sql-reference/aggregate-functions/reference/uniqhll12.md#agg_function-uniqhll12)
+-   [uniqExact](../../../sql-reference/aggregate-functions/reference/uniqexact.md#agg_function-uniqexact)
+-   [uniqTheta](../../../sql-reference/aggregate-functions/reference/uniqthetasketch.md#agg_function-uniqthetasketch)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/uniqcombined.md b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqcombined.md
new file mode 100644
index 00000000000..79357cb14ce
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqcombined.md
@@ -0,0 +1,53 @@
+---
+sidebar_position: 192
+---
+
+# uniqCombined {#agg_function-uniqcombined}
+
+Calculates the approximate number of different argument values.
+
+``` sql
+uniqCombined(HLL_precision)(x[, ...])
+```
+
+The `uniqCombined` function is a good choice for calculating the number of different values.
+
+**Arguments**
+
+The function takes a variable number of parameters. Parameters can be `Tuple`, `Array`, `Date`, `DateTime`, `String`, or numeric types.
+
+`HLL_precision` is the base-2 logarithm of the number of cells in [HyperLogLog](https://en.wikipedia.org/wiki/HyperLogLog). Optional, you can use the function as `uniqCombined(x[, ...])`. The default value for `HLL_precision` is 17, which is effectively 96 KiB of space (2^17 cells, 6 bits each).
+
+**Returned value**
+
+-   A number [UInt64](../../../sql-reference/data-types/int-uint.md)-type number.
+
+**Implementation details**
+
+Function:
+
+-   Calculates a hash (64-bit hash for `String` and 32-bit otherwise) for all parameters in the aggregate, then uses it in calculations.
+
+-   Uses a combination of three algorithms: array, hash table, and HyperLogLog with an error correction table.
+
+        For a small number of distinct elements, an array is used. When the set size is larger, a hash table is used. For a larger number of elements, HyperLogLog is used, which will occupy a fixed amount of memory.
+
+-   Provides the result deterministically (it does not depend on the query processing order).
+
+:::note    
+Since it uses 32-bit hash for non-`String` type, the result will have very high error for cardinalities significantly larger than `UINT_MAX` (error will raise quickly after a few tens of billions of distinct values), hence in this case you should use [uniqCombined64](../../../sql-reference/aggregate-functions/reference/uniqcombined64.md#agg_function-uniqcombined64)
+:::
+
+Compared to the [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq) function, the `uniqCombined`:
+
+-   Consumes several times less memory.
+-   Calculates with several times higher accuracy.
+-   Usually has slightly lower performance. In some scenarios, `uniqCombined` can perform better than `uniq`, for example, with distributed queries that transmit a large number of aggregation states over the network.
+
+**See Also**
+
+-   [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq)
+-   [uniqCombined64](../../../sql-reference/aggregate-functions/reference/uniqcombined64.md#agg_function-uniqcombined64)
+-   [uniqHLL12](../../../sql-reference/aggregate-functions/reference/uniqhll12.md#agg_function-uniqhll12)
+-   [uniqExact](../../../sql-reference/aggregate-functions/reference/uniqexact.md#agg_function-uniqexact)
+-   [uniqTheta](../../../sql-reference/aggregate-functions/reference/uniqthetasketch.md#agg_function-uniqthetasketch)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/uniqcombined64.md b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqcombined64.md
new file mode 100644
index 00000000000..fb0be23c768
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqcombined64.md
@@ -0,0 +1,7 @@
+---
+sidebar_position: 193
+---
+
+# uniqCombined64 {#agg_function-uniqcombined64}
+
+Same as [uniqCombined](../../../sql-reference/aggregate-functions/reference/uniqcombined.md#agg_function-uniqcombined), but uses 64-bit hash for all data types.
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/uniqexact.md b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqexact.md
new file mode 100644
index 00000000000..68e6bc562f9
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqexact.md
@@ -0,0 +1,26 @@
+---
+sidebar_position: 191
+---
+
+# uniqExact {#agg_function-uniqexact}
+
+Calculates the exact number of different argument values.
+
+``` sql
+uniqExact(x[, ...])
+```
+
+Use the `uniqExact` function if you absolutely need an exact result. Otherwise use the [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq) function.
+
+The `uniqExact` function uses more memory than `uniq`, because the size of the state has unbounded growth as the number of different values increases.
+
+**Arguments**
+
+The function takes a variable number of parameters. Parameters can be `Tuple`, `Array`, `Date`, `DateTime`, `String`, or numeric types.
+
+**See Also**
+
+-   [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq)
+-   [uniqCombined](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniqcombined)
+-   [uniqHLL12](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniqhll12)
+-   [uniqTheta](../../../sql-reference/aggregate-functions/reference/uniqthetasketch.md#agg_function-uniqthetasketch)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/uniqhll12.md b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqhll12.md
new file mode 100644
index 00000000000..1a13b365560
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqhll12.md
@@ -0,0 +1,40 @@
+---
+sidebar_position: 194
+---
+
+# uniqHLL12 {#agg_function-uniqhll12}
+
+Calculates the approximate number of different argument values, using the [HyperLogLog](https://en.wikipedia.org/wiki/HyperLogLog) algorithm.
+
+``` sql
+uniqHLL12(x[, ...])
+```
+
+**Arguments**
+
+The function takes a variable number of parameters. Parameters can be `Tuple`, `Array`, `Date`, `DateTime`, `String`, or numeric types.
+
+**Returned value**
+
+-   A [UInt64](../../../sql-reference/data-types/int-uint.md)-type number.
+
+**Implementation details**
+
+Function:
+
+-   Calculates a hash for all parameters in the aggregate, then uses it in calculations.
+
+-   Uses the HyperLogLog algorithm to approximate the number of different argument values.
+
+        2^12 5-bit cells are used. The size of the state is slightly more than 2.5 KB. The result is not very accurate (up to ~10% error) for small data sets (<10K elements). However, the result is fairly accurate for high-cardinality data sets (10K-100M), with a maximum error of ~1.6%. Starting from 100M, the estimation error increases, and the function will return very inaccurate results for data sets with extremely high cardinality (1B+ elements).
+
+-   Provides the determinate result (it does not depend on the query processing order).
+
+We do not recommend using this function. In most cases, use the [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq) or [uniqCombined](../../../sql-reference/aggregate-functions/reference/uniqcombined.md#agg_function-uniqcombined) function.
+
+**See Also**
+
+-   [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq)
+-   [uniqCombined](../../../sql-reference/aggregate-functions/reference/uniqcombined.md#agg_function-uniqcombined)
+-   [uniqExact](../../../sql-reference/aggregate-functions/reference/uniqexact.md#agg_function-uniqexact)
+-   [uniqTheta](../../../sql-reference/aggregate-functions/reference/uniqthetasketch.md#agg_function-uniqthetasketch)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/uniqthetasketch.md b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqthetasketch.md
new file mode 100644
index 00000000000..9b9c16922b1
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/uniqthetasketch.md
@@ -0,0 +1,39 @@
+---
+sidebar_position: 195
+---
+
+# uniqTheta {#agg_function-uniqthetasketch}
+
+Calculates the approximate number of different argument values, using the [Theta Sketch Framework](https://datasketches.apache.org/docs/Theta/ThetaSketchFramework.html).
+
+``` sql
+uniqTheta(x[, ...])
+```
+
+**Arguments**
+
+The function takes a variable number of parameters. Parameters can be `Tuple`, `Array`, `Date`, `DateTime`, `String`, or numeric types.
+
+**Returned value**
+
+-   A [UInt64](../../../sql-reference/data-types/int-uint.md)-type number.
+
+**Implementation details**
+
+Function:
+
+-   Calculates a hash for all parameters in the aggregate, then uses it in calculations.
+
+-   Uses the [KMV](https://datasketches.apache.org/docs/Theta/InverseEstimate.html) algorithm to approximate the number of different argument values.
+
+        4096(2^12) 64-bit sketch are used. The size of the state is about 41 KB.
+
+-   The relative error is 3.125% (95% confidence), see the [relative error table](https://datasketches.apache.org/docs/Theta/ThetaErrorTable.html) for detail.
+
+**See Also**
+
+-   [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq)
+-   [uniqCombined](../../../sql-reference/aggregate-functions/reference/uniqcombined.md#agg_function-uniqcombined)
+-   [uniqCombined64](../../../sql-reference/aggregate-functions/reference/uniqcombined64.md#agg_function-uniqcombined64)
+-   [uniqHLL12](../../../sql-reference/aggregate-functions/reference/uniqhll12.md#agg_function-uniqhll12)
+-   [uniqExact](../../../sql-reference/aggregate-functions/reference/uniqexact.md#agg_function-uniqexact)
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/varpop.md b/docs/en/reference/sql-reference/aggregate-functions/reference/varpop.md
new file mode 100644
index 00000000000..f16cfcdc63f
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/varpop.md
@@ -0,0 +1,13 @@
+---
+sidebar_position: 32
+---
+
+# varPop(x) {#varpopx}
+
+Calculates the amount `Σ((x - x̅)^2) / n`, where `n` is the sample size and `x̅`is the average value of `x`.
+
+In other words, dispersion for a set of values. Returns `Float64`.
+
+:::note    
+This function uses a numerically unstable algorithm. If you need [numerical stability](https://en.wikipedia.org/wiki/Numerical_stability) in calculations, use the `varPopStable` function. It works slower but provides a lower computational error.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/varsamp.md b/docs/en/reference/sql-reference/aggregate-functions/reference/varsamp.md
new file mode 100644
index 00000000000..b323f78fbd1
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/varsamp.md
@@ -0,0 +1,15 @@
+---
+sidebar_position: 33
+---
+
+# varSamp {#varsamp}
+
+Calculates the amount `Σ((x - x̅)^2) / (n - 1)`, where `n` is the sample size and `x̅`is the average value of `x`.
+
+It represents an unbiased estimate of the variance of a random variable if passed values form its sample.
+
+Returns `Float64`. When `n <= 1`, returns `+∞`.
+
+:::note    
+This function uses a numerically unstable algorithm. If you need [numerical stability](https://en.wikipedia.org/wiki/Numerical_stability) in calculations, use the `varSampStable` function. It works slower but provides a lower computational error.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/aggregate-functions/reference/welchttest.md b/docs/en/reference/sql-reference/aggregate-functions/reference/welchttest.md
new file mode 100644
index 00000000000..0aff60e7bbf
--- /dev/null
+++ b/docs/en/reference/sql-reference/aggregate-functions/reference/welchttest.md
@@ -0,0 +1,72 @@
+---
+sidebar_position: 301
+sidebar_label: welchTTest
+---
+
+# welchTTest {#welchttest}
+
+Applies Welch's t-test to samples from two populations.
+
+**Syntax**
+
+``` sql
+welchTTest([confidence_level])(sample_data, sample_index)
+```
+
+Values of both samples are in the `sample_data` column. If `sample_index` equals to 0 then the value in that row belongs to the sample from the first population. Otherwise it belongs to the sample from the second population.
+The null hypothesis is that means of populations are equal. Normal distribution is assumed. Populations may have unequal variance.
+
+**Arguments**
+
+-   `sample_data` — Sample data. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
+-   `sample_index` — Sample index. [Integer](../../../sql-reference/data-types/int-uint.md).
+
+**Parameters**
+
+-   `confidence_level` — Confidence level in order to calculate confidence intervals. [Float](../../../sql-reference/data-types/float.md).
+
+**Returned values**
+
+[Tuple](../../../sql-reference/data-types/tuple.md) with two or four elements (if the optional `confidence_level` is specified)
+
+-   calculated t-statistic. [Float64](../../../sql-reference/data-types/float.md).
+-   calculated p-value. [Float64](../../../sql-reference/data-types/float.md).
+-   [calculated confidence-interval-low.] [Float64](../../../sql-reference/data-types/float.md).
+-   [calculated confidence-interval-high.] [Float64](../../../sql-reference/data-types/float.md).
+
+
+**Example**
+
+Input table:
+
+``` text
+┌─sample_data─┬─sample_index─┐
+│        20.3 │            0 │
+│        22.1 │            0 │
+│        21.9 │            0 │
+│        18.9 │            1 │
+│        20.3 │            1 │
+│          19 │            1 │
+└─────────────┴──────────────┘
+```
+
+Query:
+
+``` sql
+SELECT welchTTest(sample_data, sample_index) FROM welch_ttest;
+```
+
+Result:
+
+``` text
+┌─welchTTest(sample_data, sample_index)─────┐
+│ (2.7988719532211235,0.051807360348581945) │
+└───────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [Welch's t-test](https://en.wikipedia.org/wiki/Welch%27s_t-test)
+-   [studentTTest function](studentttest.md#studentttest)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/aggregate-functions/reference/welchTTest/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/ansi.md b/docs/en/reference/sql-reference/ansi.md
new file mode 100644
index 00000000000..d6473e64872
--- /dev/null
+++ b/docs/en/reference/sql-reference/ansi.md
@@ -0,0 +1,190 @@
+---
+sidebar_position: 40
+sidebar_label: ANSI Compatibility
+---
+
+# ANSI SQL Compatibility of ClickHouse SQL Dialect {#ansi-sql-compatibility-of-clickhouse-sql-dialect}
+
+:::note    
+This article relies on Table 38, “Feature taxonomy and definition for mandatory features”, Annex F of [ISO/IEC CD 9075-2:2011](https://www.iso.org/obp/ui/#iso:std:iso-iec:9075:-2:ed-4:v1:en:sec:8).
+:::
+
+## Differences in Behaviour {#differences-in-behaviour}
+
+The following table lists cases when query feature works in ClickHouse, but behaves not as specified in ANSI SQL.
+
+| Feature ID | Feature Name                | Difference                                                                                                |
+|------------|-----------------------------|-----------------------------------------------------------------------------------------------------------|
+| E011       | Numeric data types          | Numeric literal with period is interpreted as approximate (`Float64`) instead of exact (`Decimal`)        |
+| E051-05    | Select items can be renamed | Item renames have a wider visibility scope than just the SELECT result                                    |
+| E141-01    | NOT NULL constraints        | `NOT NULL` is implied for table columns by default                                                        |
+| E011-04    | Arithmetic operators        | ClickHouse overflows instead of checked arithmetic and changes the result data type based on custom rules |
+
+## Feature Status {#feature-status}
+
+| Feature ID | Feature Name                                                                                                             | Status                     | Comment                                                                                                                                                                                   |
+|------------|--------------------------------------------------------------------------------------------------------------------------|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| **E011**   | **Numeric data types**                                                                                                   | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| E011-01    | INTEGER and SMALLINT data types                                                                                          | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E011-02    | REAL, DOUBLE PRECISION and FLOAT data types data types                                                                   | <span class="text-success">Yes</span>     |                                                                                                               |
+| E011-03    | DECIMAL and NUMERIC data types                                                                                           | <span class="text-success">Yes</span>     |                                                                                                                                          |
+| E011-04    | Arithmetic operators                                                                                                     | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E011-05    | Numeric comparison                                                                                                       | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E011-06    | Implicit casting among the numeric data types                                                                            | <span class="text-danger">No</span>           | ANSI SQL allows arbitrary implicit cast between numeric types, while ClickHouse relies on functions having multiple overloads instead of implicit cast                                    |
+| **E021**   | **Character string types**                                                                                               | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| E021-01    | CHARACTER data type                                                                                                      | <span class="text-success">Yes</span>           |                                                                                                                                                                                           |
+| E021-02    | CHARACTER VARYING data type                                                                                              | <span class="text-success">Yes</span>           |                                                                                                                       |
+| E021-03    | Character literals                                                                                                       | <span class="text-success">Yes</span>     |                                                                                                               |
+| E021-04    | CHARACTER_LENGTH function                                                                                               | <span class="text-warning">Partial</span>     | No `USING` clause                                                                                                                                                                         |
+| E021-05    | OCTET_LENGTH function                                                                                                   | <span class="text-danger">No</span>           | `LENGTH` behaves similarly                                                                                                                                                                |
+| E021-06    | SUBSTRING                                                                                                                | <span class="text-warning">Partial</span>     | No support for `SIMILAR` and `ESCAPE` clauses, no `SUBSTRING_REGEX` variant                                                                                                               |
+| E021-07    | Character concatenation                                                                                                  | <span class="text-warning">Partial</span>     | No `COLLATE` clause                                                                                                                                                                       |
+| E021-08    | UPPER and LOWER functions                                                                                                | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E021-09    | TRIM function                                                                                                            | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E021-10    | Implicit casting among the fixed-length and variable-length character string types                                       | <span class="text-warning">Partial</span>           | ANSI SQL allows arbitrary implicit cast between string types, while ClickHouse relies on functions having multiple overloads instead of implicit cast                                     |
+| E021-11    | POSITION function                                                                                                        | <span class="text-warning">Partial</span>     | No support for `IN` and `USING` clauses, no `POSITION_REGEX` variant                                                                                                                      |
+| E021-12    | Character comparison                                                                                                     | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| **E031**   | **Identifiers**                                                                                                          | <span class="text-warning">Partial</span>|                                                                                                                                                                                           |
+| E031-01    | Delimited identifiers                                                                                                    | <span class="text-warning">Partial</span>     | Unicode literal support is limited                                                                                                                                                        |
+| E031-02    | Lower case identifiers                                                                                                   | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E031-03    | Trailing underscore                                                                                                      | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| **E051**   | **Basic query specification**                                                                                            | <span class="text-warning">Partial</span>|                                                                                                                                                                                           |
+| E051-01    | SELECT DISTINCT                                                                                                          | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E051-02    | GROUP BY clause                                                                                                          | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E051-04    | GROUP BY can contain columns not in `<select list>`                                                                      | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E051-05    | Select items can be renamed                                                                                              | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E051-06    | HAVING clause                                                                                                            | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E051-07    | Qualified \* in select list                                                                                              | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E051-08    | Correlation name in the FROM clause                                                                                      | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E051-09    | Rename columns in the FROM clause                                                                                        | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **E061**   | **Basic predicates and search conditions**                                                                               | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| E061-01    | Comparison predicate                                                                                                     | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E061-02    | BETWEEN predicate                                                                                                        | <span class="text-warning">Partial</span>     | No `SYMMETRIC` and `ASYMMETRIC` clause                                                                                                                                                    |
+| E061-03    | IN predicate with list of values                                                                                         | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E061-04    | LIKE predicate                                                                                                           | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E061-05    | LIKE predicate: ESCAPE clause                                                                                            | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E061-06    | NULL predicate                                                                                                           | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E061-07    | Quantified comparison predicate                                                                                          | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E061-08    | EXISTS predicate                                                                                                         | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E061-09    | Subqueries in comparison predicate                                                                                       | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E061-11    | Subqueries in IN predicate                                                                                               | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E061-12    | Subqueries in quantified comparison predicate                                                                            | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E061-13    | Correlated subqueries                                                                                                    | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E061-14    | Search condition                                                                                                         | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| **E071**   | **Basic query expressions**                                                                                              | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| E071-01    | UNION DISTINCT table operator                                                                                            | <span class="text-success">Yes</span>           |                                                                                                                                                                                           |
+| E071-02    | UNION ALL table operator                                                                                                 | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E071-03    | EXCEPT DISTINCT table operator                                                                                           | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E071-05    | Columns combined via table operators need not have exactly the same data type                                            | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E071-06    | Table operators in subqueries                                                                                            | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| **E081**   | **Basic privileges**                                                                                                     | <span class="text-success">Yes</span>             |
+| E081-01    | SELECT privilege at the table level                                                                                      | <span class="text-success">Yes</span>             | 
+| E081-02    | DELETE privilege                                                                                                         |                                                   |
+| E081-03    | INSERT privilege at the table level                                                                                      | <span class="text-success">Yes</span>             |
+| E081-04    | UPDATE privilege at the table level                                                                                      | <span class="text-success">Yes</span>             | 
+| E081-05    | UPDATE privilege at the column level                                                                                     |                                                   |
+| E081-06    | REFERENCES privilege at the table level  | | |
+| E081-07    | REFERENCES privilege at the column level | | |
+| E081-08    | WITH GRANT OPTION | <span class="text-success">Yes</span> | |
+| E081-09    | USAGE privilege | | |
+| E081-10    | EXECUTE privilege | | |
+| **E091**   | **Set functions**                                                                                                        |<span class="text-success">Yes</span>              |
+| E091-01    | AVG                                                                                                                      | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E091-02    | COUNT                                                                                                                    | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E091-03    | MAX                                                                                                                      | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E091-04    | MIN                                                                                                                      | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E091-05    | SUM                                                                                                                      | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E091-06    | ALL quantifier                                                                                                           | <span class="text-success">Yes</span>           |                                                                                                                                                                                           |
+| E091-07    | DISTINCT quantifier                                                                                                      | <span class="text-success">Yes</span>     | Not all aggregate functions supported                                                                                                                                                     |
+| **E101**   | **Basic data manipulation**                                                                                              | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| E101-01    | INSERT statement                                                                                                         | <span class="text-success">Yes</span>         | Note: primary key in ClickHouse does not imply the `UNIQUE` constraint                                                                                                                    |
+| E101-03    | Searched UPDATE statement                                                                                                | <span class="text-warning">Partial</span>           | There’s an `ALTER UPDATE` statement for batch data modification                                                                                                                           |
+| E101-04    | Searched DELETE statement                                                                                                | <span class="text-warning">Partial</span>           | There’s an `ALTER DELETE` statement for batch data removal                                                                                                                                |
+| **E111**   | **Single row SELECT statement**                                                                                          | <span class="text-danger">No</span>        |                                                                                                                                                                                           |
+| **E121**   | **Basic cursor support**                                                                                                 | <span class="text-danger">No</span>        |                                                                                                                                                                                           |
+| E121-01    | DECLARE CURSOR                                                                                                           | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E121-02    | ORDER BY columns need not be in select list                                                                              | <span class="text-success">Yes</span>           |                                                                                                                                                                                           |
+| E121-03    | Value expressions in ORDER BY clause                                                                                     | <span class="text-success">Yes</span>           |                                                                                                                                                                                           |
+| E121-04    | OPEN statement                                                                                                           | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E121-06    | Positioned UPDATE statement                                                                                              | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E121-07    | Positioned DELETE statement                                                                                              | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E121-08    | CLOSE statement                                                                                                          | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E121-10    | FETCH statement: implicit NEXT                                                                                           | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E121-17    | WITH HOLD cursors                                                                                                        | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **E131**   | **Null value support (nulls in lieu of values)**                                                                         | <span class="text-success">Yes</span>             | Some restrictions apply  |
+| **E141**   | **Basic integrity constraints**                                                                                          | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| E141-01    | NOT NULL constraints                                                                                                     | <span class="text-success">Yes</span>         | Note: `NOT NULL` is implied for table columns by default                                                                                                                                  |
+| E141-02    | UNIQUE constraint of NOT NULL columns                                                                                    | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E141-03    | PRIMARY KEY constraints                                                                                                  | <span class="text-warning">Partial</span>           |                                                                                                                                                                                           |
+| E141-04    | Basic FOREIGN KEY constraint with the NO ACTION default for both referential delete action and referential update action | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E141-06    | CHECK constraint                                                                                                         | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E141-07    | Column defaults                                                                                                          | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E141-08    | NOT NULL inferred on PRIMARY KEY                                                                                         | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| E141-10    | Names in a foreign key can be specified in any order                                                                     | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **E151**   | **Transaction support**                                                                                                  | <span class="text-danger">No</span>       |                                                                                                                                                                                           |
+| E151-01    | COMMIT statement                                                                                                         | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E151-02    | ROLLBACK statement                                                                                                       | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **E152**   | **Basic SET TRANSACTION statement**                                                                                      | <span class="text-danger">No</span>       |                                                                                                                                                                                           |
+| E152-01    | SET TRANSACTION statement: ISOLATION LEVEL SERIALIZABLE clause                                                           | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| E152-02    | SET TRANSACTION statement: READ ONLY and READ WRITE clauses                                                              | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **E153**   | **Updatable queries with subqueries**                                                                                    | <span class="text-success">Yes</span>       |                                                                                                                                                                                           |
+| **E161**   | **SQL comments using leading double minus**                                                                              | <span class="text-success">Yes</span>     |                                                                                                                                                                                           |
+| **E171**   | **SQLSTATE support**                                                                                                     | <span class="text-danger">No</span>       |                                                                                                                                                                                           |
+| **E182**   | **Host language binding**                                                                                                | <span class="text-danger">No</span>       |                                                                                                                                                                                           |
+| **F031**   | **Basic schema manipulation**                                                                                            | <span class="text-warning">Partial</span>|                                                                                                                                                                                           |
+| F031-01    | CREATE TABLE statement to create persistent base tables                                                                  | <span class="text-warning">Partial</span>     | No `SYSTEM VERSIONING`, `ON COMMIT`, `GLOBAL`, `LOCAL`, `PRESERVE`, `DELETE`, `REF IS`, `WITH OPTIONS`, `UNDER`, `LIKE`, `PERIOD FOR` clauses and no support for user resolved data types |
+| F031-02    | CREATE VIEW statement                                                                                                    | <span class="text-warning">Partial</span>     | No `RECURSIVE`, `CHECK`, `UNDER`, `WITH OPTIONS` clauses and no support for user resolved data types                                                                                      |
+| F031-03    | GRANT statement                                                                                                          | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F031-04    | ALTER TABLE statement: ADD COLUMN clause                                                                                 | <span class="text-success">Yes</span>     | No support for `GENERATED` clause and system time period                                                                                                                                  |
+| F031-13    | DROP TABLE statement: RESTRICT clause                                                                                    | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| F031-16    | DROP VIEW statement: RESTRICT clause                                                                                     | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| F031-19    | REVOKE statement: RESTRICT clause                                                                                        | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **F041**   | **Basic joined table**                                                                                                   | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| F041-01    | Inner join (but not necessarily the INNER keyword)                                                                       | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F041-02    | INNER keyword                                                                                                            | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F041-03    | LEFT OUTER JOIN                                                                                                          | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F041-04    | RIGHT OUTER JOIN                                                                                                         | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F041-05    | Outer joins can be nested                                                                                                | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F041-07    | The inner table in a left or right outer join can also be used in an inner join                                          | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F041-08    | All comparison operators are supported (rather than just =)                                                              | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **F051**   | **Basic date and time**                                                                                                  | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| F051-01    | DATE data type (including support of DATE literal)                                                                       | <span class="text-success">Yes</span>     |                       |
+| F051-02    | TIME data type (including support of TIME literal) with fractional seconds precision of at least 0                       | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| F051-03    | TIMESTAMP data type (including support of TIMESTAMP literal) with fractional seconds precision of at least 0 and 6       | <span class="text-success">Yes</span> | |
+| F051-04    | Comparison predicate on DATE, TIME, and TIMESTAMP data types                                                             | <span class="text-success">Yes</span> | |
+| F051-05    | Explicit CAST between datetime types and character string types                                                          | <span class="text-success">Yes</span> | |
+| F051-06    | CURRENT_DATE                                                                                                            | <span class="text-danger">No</span>           | `today()` is similar                                                                                                                                                                      |
+| F051-07    | LOCALTIME                                                                                                                | <span class="text-danger">No</span>           | `now()` is similar                                                                                                                                                                        |
+| F051-08    | LOCALTIMESTAMP                                                                                                           | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **F081**   | **UNION and EXCEPT in views**                                                                                            | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| **F131**   | **Grouped operations**                                                                                                   | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| F131-01    | WHERE, GROUP BY, and HAVING clauses supported in queries with grouped views                                              | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F131-02    | Multiple tables supported in queries with grouped views                                                                  | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F131-03    | Set functions supported in queries with grouped views                                                                    | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F131-04    | Subqueries with GROUP BY and HAVING clauses and grouped views                                                            | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F131-05    | Single row SELECT with GROUP BY and HAVING clauses and grouped views                                                     | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **F181**   | **Multiple module support**                                                                                              | <span class="text-danger">No</span>       |                                                                                                                                                                                           |
+| **F201**   | **CAST function**                                                                                                        | <span class="text-success">Yes</span>     |                                                                                                                                                                                           |
+| **F221**   | **Explicit defaults**                                                                                                    | <span class="text-danger">No</span>       |                                                                                                                                                                                           |
+| **F261**   | **CASE expression**                                                                                                      | <span class="text-success">Yes</span>     |                                                                                                                                                                                           |
+| F261-01    | Simple CASE                                                                                                              | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F261-02    | Searched CASE                                                                                                            | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F261-03    | NULLIF                                                                                                                   | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F261-04    | COALESCE                                                                                                                 | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| **F311**   | **Schema definition statement**                                                                                          | <span class="text-warning">Partial</span> |                                                                                                                                                                                           |
+| F311-01    | CREATE SCHEMA                                                                                                            | <span class="text-warning">Partial</span>         | See CREATE DATABASE |
+| F311-02    | CREATE TABLE for persistent base tables                                                                                  | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F311-03    | CREATE VIEW                                                                                                              | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| F311-04    | CREATE VIEW: WITH CHECK OPTION                                                                                           | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| F311-05    | GRANT statement                                                                                                          | <span class="text-success">Yes</span>         |                                                                                                                                                                                           |
+| **F471**   | **Scalar subquery values**                                                                                               | <span class="text-success">Yes</span>     |                                                                                                                                                                                           |
+| **F481**   | **Expanded NULL predicate**                                                                                              | <span class="text-success">Yes</span>     |                                                                                                                                                                                           |
+| **F812**   | **Basic flagging**                                                                                                       | <span class="text-danger">No</span>       |                                                                                                                                                                                           |
+| **S011**   | **Distinct data types** | | |
+| **T321**   | **Basic SQL-invoked routines**                                                                                           | <span class="text-danger">No</span>       |                                                                                                                                                                                           |
+| T321-01    | User-defined functions with no overloading                                                                               | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| T321-02    | User-defined stored procedures with no overloading                                                                       | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| T321-03    | Function invocation                                                                                                      | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| T321-04    | CALL statement                                                                                                           | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| T321-05    | RETURN statement                                                                                                         | <span class="text-danger">No</span>           |                                                                                                                                                                                           |
+| **T631**   | **IN predicate with one list element**                                                                                   | <span class="text-success">Yes</span>     |                                                                                                                                                                                           |
diff --git a/docs/en/reference/sql-reference/data-types/aggregatefunction.md b/docs/en/reference/sql-reference/data-types/aggregatefunction.md
new file mode 100644
index 00000000000..6dc89e2864f
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/aggregatefunction.md
@@ -0,0 +1,66 @@
+---
+sidebar_position: 53
+sidebar_label: AggregateFunction
+---
+
+# AggregateFunction {#data-type-aggregatefunction}
+
+Aggregate functions can have an implementation-defined intermediate state that can be serialized to an `AggregateFunction(…)` data type and stored in a table, usually, by means of [a materialized view](../../sql-reference/statements/create/view.md). The common way to produce an aggregate function state is by calling the aggregate function with the `-State` suffix. To get the final result of aggregation in the future, you must use the same aggregate function with the `-Merge`suffix.
+
+`AggregateFunction(name, types_of_arguments…)` — parametric data type.
+
+**Parameters**
+
+-   Name of the aggregate function. If the function is parametric, specify its parameters too.
+
+-   Types of the aggregate function arguments.
+
+**Example**
+
+``` sql
+CREATE TABLE t
+(
+    column1 AggregateFunction(uniq, UInt64),
+    column2 AggregateFunction(anyIf, String, UInt8),
+    column3 AggregateFunction(quantiles(0.5, 0.9), UInt64)
+) ENGINE = ...
+```
+
+[uniq](../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq), anyIf ([any](../../sql-reference/aggregate-functions/reference/any.md#agg_function-any)+[If](../../sql-reference/aggregate-functions/combinators.md#agg-functions-combinator-if)) and [quantiles](../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) are the aggregate functions supported in ClickHouse.
+
+## Usage {#usage}
+
+### Data Insertion {#data-insertion}
+
+To insert data, use `INSERT SELECT` with aggregate `-State`- functions.
+
+**Function examples**
+
+``` sql
+uniqState(UserID)
+quantilesState(0.5, 0.9)(SendTiming)
+```
+
+In contrast to the corresponding functions `uniq` and `quantiles`, `-State`- functions return the state, instead of the final value. In other words, they return a value of `AggregateFunction` type.
+
+In the results of `SELECT` query, the values of `AggregateFunction` type have implementation-specific binary representation for all of the ClickHouse output formats. If dump data into, for example, `TabSeparated` format with `SELECT` query, then this dump can be loaded back using `INSERT` query.
+
+### Data Selection {#data-selection}
+
+When selecting data from `AggregatingMergeTree` table, use `GROUP BY` clause and the same aggregate functions as when inserting data, but using `-Merge`suffix.
+
+An aggregate function with `-Merge` suffix takes a set of states, combines them, and returns the result of complete data aggregation.
+
+For example, the following two queries return the same result:
+
+``` sql
+SELECT uniq(UserID) FROM table
+
+SELECT uniqMerge(state) FROM (SELECT uniqState(UserID) AS state FROM table GROUP BY RegionID)
+```
+
+## Usage Example {#usage-example}
+
+See [AggregatingMergeTree](../../engines/table-engines/mergetree-family/aggregatingmergetree.md) engine description.
+
+[Original article](https://clickhouse.com/docs/en/data_types/nested_data_structures/aggregatefunction/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/array.md b/docs/en/reference/sql-reference/data-types/array.md
new file mode 100644
index 00000000000..909df86ec2f
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/array.md
@@ -0,0 +1,99 @@
+---
+sidebar_position: 52
+sidebar_label: Array(T)
+---
+
+# Array(t) {#data-type-array}
+
+An array of `T`-type items, with the starting array index as 1. `T` can be any data type, including an array.
+
+## Creating an Array {#creating-an-array}
+
+You can use a function to create an array:
+
+``` sql
+array(T)
+```
+
+You can also use square brackets.
+
+``` sql
+[]
+```
+
+Example of creating an array:
+
+``` sql
+SELECT array(1, 2) AS x, toTypeName(x)
+```
+
+``` text
+┌─x─────┬─toTypeName(array(1, 2))─┐
+│ [1,2] │ Array(UInt8)            │
+└───────┴─────────────────────────┘
+```
+
+``` sql
+SELECT [1, 2] AS x, toTypeName(x)
+```
+
+``` text
+┌─x─────┬─toTypeName([1, 2])─┐
+│ [1,2] │ Array(UInt8)       │
+└───────┴────────────────────┘
+```
+
+## Working with Data Types {#working-with-data-types}
+
+The maximum size of an array is limited to one million elements.
+
+When creating an array on the fly, ClickHouse automatically defines the argument type as the narrowest data type that can store all the listed arguments. If there are any [Nullable](../../sql-reference/data-types/nullable.md#data_type-nullable) or literal [NULL](../../sql-reference/syntax.md#null-literal) values, the type of an array element also becomes [Nullable](../../sql-reference/data-types/nullable.md).
+
+If ClickHouse couldn’t determine the data type, it generates an exception. For instance, this happens when trying to create an array with strings and numbers simultaneously (`SELECT array(1, 'a')`).
+
+Examples of automatic data type detection:
+
+``` sql
+SELECT array(1, 2, NULL) AS x, toTypeName(x)
+```
+
+``` text
+┌─x──────────┬─toTypeName(array(1, 2, NULL))─┐
+│ [1,2,NULL] │ Array(Nullable(UInt8))        │
+└────────────┴───────────────────────────────┘
+```
+
+If you try to create an array of incompatible data types, ClickHouse throws an exception:
+
+``` sql
+SELECT array(1, 'a')
+```
+
+``` text
+Received exception from server (version 1.1.54388):
+Code: 386. DB::Exception: Received from localhost:9000, 127.0.0.1. DB::Exception: There is no supertype for types UInt8, String because some of them are String/FixedString and some of them are not.
+```
+
+## Array Size {#array-size}
+
+It is possible to find the size of an array by using the `size0` subcolumn without reading the whole column. For multi-dimensional arrays you can use `sizeN-1`, where `N` is the wanted dimension.
+
+**Example**
+
+Query:
+
+```sql
+CREATE TABLE t_arr (`arr` Array(Array(Array(UInt32)))) ENGINE = MergeTree ORDER BY tuple();
+
+INSERT INTO t_arr VALUES ([[[12, 13, 0, 1],[12]]]);
+
+SELECT arr.size0, arr.size1, arr.size2 FROM t_arr;
+```
+
+Result:
+
+``` text
+┌─arr.size0─┬─arr.size1─┬─arr.size2─┐
+│         1 │ [2]       │ [[4,1]]   │
+└───────────┴───────────┴───────────┘
+```
diff --git a/docs/en/reference/sql-reference/data-types/boolean.md b/docs/en/reference/sql-reference/data-types/boolean.md
new file mode 100644
index 00000000000..a20e30777af
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/boolean.md
@@ -0,0 +1,10 @@
+---
+sidebar_position: 43
+sidebar_label: Boolean
+---
+
+# Boolean Values {#boolean-values}
+
+There is no separate type for boolean values. Use UInt8 type, restricted to the values 0 or 1.
+
+[Original article](https://clickhouse.com/docs/en/data_types/boolean/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/date.md b/docs/en/reference/sql-reference/data-types/date.md
new file mode 100644
index 00000000000..bc3fda4a9d0
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/date.md
@@ -0,0 +1,43 @@
+---
+sidebar_position: 47
+sidebar_label: Date
+---
+
+# Date {#data_type-date}
+
+A date. Stored in two bytes as the number of days since 1970-01-01 (unsigned). Allows storing values from just after the beginning of the Unix Epoch to the upper threshold defined by a constant at the compilation stage (currently, this is until the year 2149, but the final fully-supported year is 2148).
+
+Supported range of values: \[1970-01-01, 2149-06-06\].
+
+The date value is stored without the time zone.
+
+**Example**
+
+Creating a table with a `Date`-type column and inserting data into it:
+
+``` sql
+CREATE TABLE dt
+(
+    `timestamp` Date,
+    `event_id` UInt8
+)
+ENGINE = TinyLog;
+```
+
+``` sql
+INSERT INTO dt VALUES (1546300800, 1), ('2019-01-01', 2);
+SELECT * FROM dt;
+```
+
+``` text
+┌──timestamp─┬─event_id─┐
+│ 2019-01-01 │        1 │
+│ 2019-01-01 │        2 │
+└────────────┴──────────┘
+```
+
+**See Also**
+
+-   [Functions for working with dates and times](../../sql-reference/functions/date-time-functions.md)
+-   [Operators for working with dates and times](../../sql-reference/operators/index.md#operators-datetime)
+-   [`DateTime` data type](../../sql-reference/data-types/datetime.md)
diff --git a/docs/en/reference/sql-reference/data-types/date32.md b/docs/en/reference/sql-reference/data-types/date32.md
new file mode 100644
index 00000000000..46c9fe00b34
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/date32.md
@@ -0,0 +1,40 @@
+---
+sidebar_position: 48
+sidebar_label: Date32
+---
+
+# Date32 {#data_type-datetime32}
+
+A date. Supports the date range same with [Datetime64](../../sql-reference/data-types/datetime64.md). Stored in four bytes as the number of days since 1925-01-01. Allows storing values till 2283-11-11. 
+
+**Examples**
+
+Creating a table with a `Date32`-type column and inserting data into it:
+
+``` sql
+CREATE TABLE new
+(
+    `timestamp` Date32,
+    `event_id` UInt8
+)
+ENGINE = TinyLog;
+```
+
+``` sql
+INSERT INTO new VALUES (4102444800, 1), ('2100-01-01', 2);
+SELECT * FROM new;
+```
+
+``` text
+┌──timestamp─┬─event_id─┐
+│ 2100-01-01 │        1 │
+│ 2100-01-01 │        2 │
+└────────────┴──────────┘
+```
+
+**See Also**
+
+-   [toDate32](../../sql-reference/functions/type-conversion-functions.md#todate32)
+-   [toDate32OrZero](../../sql-reference/functions/type-conversion-functions.md#todate32-or-zero)
+-   [toDate32OrNull](../../sql-reference/functions/type-conversion-functions.md#todate32-or-null) 
+
diff --git a/docs/en/reference/sql-reference/data-types/datetime.md b/docs/en/reference/sql-reference/data-types/datetime.md
new file mode 100644
index 00000000000..cae83ac9a31
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/datetime.md
@@ -0,0 +1,148 @@
+---
+sidebar_position: 48
+sidebar_label: DateTime
+---
+
+# Datetime {#data_type-datetime}
+
+Allows to store an instant in time, that can be expressed as a calendar date and a time of a day.
+
+Syntax:
+
+``` sql
+DateTime([timezone])
+```
+
+Supported range of values: \[1970-01-01 00:00:00, 2106-02-07 06:28:15\].
+
+Resolution: 1 second.
+
+## Usage Remarks {#usage-remarks}
+
+The point in time is saved as a [Unix timestamp](https://en.wikipedia.org/wiki/Unix_time), regardless of the time zone or daylight saving time. The time zone affects how the values of the `DateTime` type values are displayed in text format and how the values specified as strings are parsed (‘2020-01-01 05:00:01’).
+
+Timezone agnostic unix timestamp is stored in tables, and the timezone is used to transform it to text format or back during data import/export or to make calendar calculations on the values (example: `toDate`, `toHour` functions et cetera). The time zone is not stored in the rows of the table (or in resultset), but is stored in the column metadata.
+
+A list of supported time zones can be found in the [IANA Time Zone Database](https://www.iana.org/time-zones) and also can be queried by `SELECT * FROM system.time_zones`. [The list](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones) is also available at Wikipedia.
+
+You can explicitly set a time zone for `DateTime`-type columns when creating a table. Example: `DateTime('UTC')`. If the time zone isn’t set, ClickHouse uses the value of the [timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) parameter in the server settings or the operating system settings at the moment of the ClickHouse server start.
+
+The [clickhouse-client](../../interfaces/cli.md) applies the server time zone by default if a time zone isn’t explicitly set when initializing the data type. To use the client time zone, run `clickhouse-client` with the `--use_client_time_zone` parameter.
+
+ClickHouse outputs values depending on the value of the [date_time_output_format](../../operations/settings/settings.md#settings-date_time_output_format) setting. `YYYY-MM-DD hh:mm:ss` text format by default. Additionaly you can change the output with the [formatDateTime](../../sql-reference/functions/date-time-functions.md#formatdatetime) function.
+
+When inserting data into ClickHouse, you can use different formats of date and time strings, depending on the value of the [date_time_input_format](../../operations/settings/settings.md#settings-date_time_input_format) setting.
+
+## Examples {#examples}
+
+**1.** Creating a table with a `DateTime`-type column and inserting data into it:
+
+``` sql
+CREATE TABLE dt
+(
+    `timestamp` DateTime('Asia/Istanbul'),
+    `event_id` UInt8
+)
+ENGINE = TinyLog;
+```
+
+``` sql
+INSERT INTO dt Values (1546300800, 1), ('2019-01-01 00:00:00', 2);
+```
+
+``` sql
+SELECT * FROM dt;
+```
+
+``` text
+┌───────────timestamp─┬─event_id─┐
+│ 2019-01-01 03:00:00 │        1 │
+│ 2019-01-01 00:00:00 │        2 │
+└─────────────────────┴──────────┘
+```
+
+-   When inserting datetime as an integer, it is treated as Unix Timestamp (UTC). `1546300800` represents `'2019-01-01 00:00:00'` UTC. However, as `timestamp` column has `Asia/Istanbul` (UTC+3) timezone specified, when outputting as string the value will be shown as `'2019-01-01 03:00:00'`
+-   When inserting string value as datetime, it is treated as being in column timezone. `'2019-01-01 00:00:00'` will be treated as being in `Asia/Istanbul` timezone and saved as `1546290000`.
+
+**2.** Filtering on `DateTime` values
+
+``` sql
+SELECT * FROM dt WHERE timestamp = toDateTime('2019-01-01 00:00:00', 'Asia/Istanbul')
+```
+
+``` text
+┌───────────timestamp─┬─event_id─┐
+│ 2019-01-01 00:00:00 │        2 │
+└─────────────────────┴──────────┘
+```
+
+`DateTime` column values can be filtered using a string value in `WHERE` predicate. It will be converted to `DateTime` automatically:
+
+``` sql
+SELECT * FROM dt WHERE timestamp = '2019-01-01 00:00:00'
+```
+
+``` text
+┌───────────timestamp─┬─event_id─┐
+│ 2019-01-01 03:00:00 │        1 │
+└─────────────────────┴──────────┘
+```
+
+**3.** Getting a time zone for a `DateTime`-type column:
+
+``` sql
+SELECT toDateTime(now(), 'Asia/Istanbul') AS column, toTypeName(column) AS x
+```
+
+``` text
+┌──────────────column─┬─x─────────────────────────┐
+│ 2019-10-16 04:12:04 │ DateTime('Asia/Istanbul') │
+└─────────────────────┴───────────────────────────┘
+```
+
+**4.** Timezone conversion
+
+``` sql
+SELECT
+toDateTime(timestamp, 'Europe/London') as lon_time,
+toDateTime(timestamp, 'Asia/Istanbul') as mos_time
+FROM dt
+```
+
+``` text
+┌───────────lon_time──┬────────────mos_time─┐
+│ 2019-01-01 00:00:00 │ 2019-01-01 03:00:00 │
+│ 2018-12-31 21:00:00 │ 2019-01-01 00:00:00 │
+└─────────────────────┴─────────────────────┘
+```
+
+As timezone conversion only changes the metadata, the operation has no computation cost.
+
+
+## Limitations on timezones support
+
+Some timezones may not be supported completely. There are a few cases:
+
+If the offset from UTC is not a multiple of 15 minutes, the calculation of hours and minutes can be incorrect. For example, the time zone in Monrovia, Liberia has offset UTC -0:44:30 before 7 Jan 1972. If you are doing calculations on the historical time in Monrovia timezone, the time processing functions may give incorrect results. The results after 7 Jan 1972 will be correct nevertheless.
+
+If the time transition (due to daylight saving time or for other reasons) was performed at a point of time that is not a multiple of 15 minutes, you can also get incorrect results at this specific day.
+
+Non-monotonic calendar dates. For example, in Happy Valley - Goose Bay, the time was transitioned one hour backwards at 00:01:00 7 Nov 2010 (one minute after midnight). So after 6th Nov has ended, people observed a whole one minute of 7th Nov, then time was changed back to 23:01 6th Nov and after another 59 minutes the 7th Nov started again. ClickHouse does not (yet) support this kind of fun. During these days the results of time processing functions may be slightly incorrect.
+
+Similar issue exists for Casey Antarctic station in year 2010. They changed time three hours back at 5 Mar, 02:00. If you are working in antarctic station, please don't afraid to use ClickHouse. Just make sure you set timezone to UTC or be aware of inaccuracies.
+
+Time shifts for multiple days. Some pacific islands changed their timezone offset from UTC+14 to UTC-12. That's alright but some inaccuracies may present if you do calculations with their timezone for historical time points at the days of conversion.
+
+
+## See Also {#see-also}
+
+-   [Type conversion functions](../../sql-reference/functions/type-conversion-functions.md)
+-   [Functions for working with dates and times](../../sql-reference/functions/date-time-functions.md)
+-   [Functions for working with arrays](../../sql-reference/functions/array-functions.md)
+-   [The `date_time_input_format` setting](../../operations/settings/settings.md#settings-date_time_input_format)
+-   [The `date_time_output_format` setting](../../operations/settings/settings.md#settings-date_time_output_format)
+-   [The `timezone` server configuration parameter](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone)
+-   [Operators for working with dates and times](../../sql-reference/operators/index.md#operators-datetime)
+-   [The `Date` data type](../../sql-reference/data-types/date.md)
+
+[Original article](https://clickhouse.com/docs/en/data_types/datetime/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/datetime64.md b/docs/en/reference/sql-reference/data-types/datetime64.md
new file mode 100644
index 00000000000..aefd7e4a18b
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/datetime64.md
@@ -0,0 +1,106 @@
+---
+sidebar_position: 49
+sidebar_label: DateTime64
+---
+
+# Datetime64 {#data_type-datetime64}
+
+Allows to store an instant in time, that can be expressed as a calendar date and a time of a day, with defined sub-second precision
+
+Tick size (precision): 10<sup>-precision</sup> seconds. Valid range: [ 0 : 9 ]. 
+Typically are used - 3 (milliseconds), 6 (microseconds), 9 (nanoseconds).
+
+**Syntax:**
+
+``` sql
+DateTime64(precision, [timezone])
+```
+
+Internally, stores data as a number of ‘ticks’ since epoch start (1970-01-01 00:00:00 UTC) as Int64. The tick resolution is determined by the precision parameter. Additionally, the `DateTime64` type can store time zone that is the same for the entire column, that affects how the values of the `DateTime64` type values are displayed in text format and how the values specified as strings are parsed (‘2020-01-01 05:00:01.000’). The time zone is not stored in the rows of the table (or in resultset), but is stored in the column metadata. See details in [DateTime](../../sql-reference/data-types/datetime.md).
+
+Supported range of values: \[1925-01-01 00:00:00, 2283-11-11 23:59:59.99999999\] (Note: The precision of the maximum value is 8).
+
+## Examples {#examples}
+
+1. Creating a table with `DateTime64`-type column and inserting data into it:
+
+``` sql
+CREATE TABLE dt
+(
+    `timestamp` DateTime64(3, 'Asia/Istanbul'),
+    `event_id` UInt8
+)
+ENGINE = TinyLog;
+```
+
+``` sql
+INSERT INTO dt Values (1546300800000, 1), ('2019-01-01 00:00:00', 2);
+```
+
+``` sql
+SELECT * FROM dt;
+```
+
+``` text
+┌───────────────timestamp─┬─event_id─┐
+│ 2019-01-01 03:00:00.000 │        1 │
+│ 2019-01-01 00:00:00.000 │        2 │
+└─────────────────────────┴──────────┘
+```
+
+-   When inserting datetime as an integer, it is treated as an appropriately scaled Unix Timestamp (UTC). `1546300800000` (with precision 3) represents `'2019-01-01 00:00:00'` UTC. However, as `timestamp` column has `Asia/Istanbul` (UTC+3) timezone specified, when outputting as a string the value will be shown as `'2019-01-01 03:00:00'`.
+-   When inserting string value as datetime, it is treated as being in column timezone. `'2019-01-01 00:00:00'` will be treated as being in `Asia/Istanbul` timezone and stored as `1546290000000`.
+
+2. Filtering on `DateTime64` values
+
+``` sql
+SELECT * FROM dt WHERE timestamp = toDateTime64('2019-01-01 00:00:00', 3, 'Asia/Istanbul');
+```
+
+``` text
+┌───────────────timestamp─┬─event_id─┐
+│ 2019-01-01 00:00:00.000 │        2 │
+└─────────────────────────┴──────────┘
+```
+
+Unlike `DateTime`, `DateTime64` values are not converted from `String` automatically.
+
+3. Getting a time zone for a `DateTime64`-type value:
+
+``` sql
+SELECT toDateTime64(now(), 3, 'Asia/Istanbul') AS column, toTypeName(column) AS x;
+```
+
+``` text
+┌──────────────────column─┬─x──────────────────────────────┐
+│ 2019-10-16 04:12:04.000 │ DateTime64(3, 'Asia/Istanbul') │
+└─────────────────────────┴────────────────────────────────┘
+```
+
+4. Timezone conversion
+
+``` sql
+SELECT
+toDateTime64(timestamp, 3, 'Europe/London') as lon_time,
+toDateTime64(timestamp, 3, 'Asia/Istanbul') as mos_time
+FROM dt;
+```
+
+``` text
+┌───────────────lon_time──┬────────────────mos_time─┐
+│ 2019-01-01 00:00:00.000 │ 2019-01-01 03:00:00.000 │
+│ 2018-12-31 21:00:00.000 │ 2019-01-01 00:00:00.000 │
+└─────────────────────────┴─────────────────────────┘
+```
+
+**See Also**
+
+-   [Type conversion functions](../../sql-reference/functions/type-conversion-functions.md)
+-   [Functions for working with dates and times](../../sql-reference/functions/date-time-functions.md)
+-   [Functions for working with arrays](../../sql-reference/functions/array-functions.md)
+-   [The `date_time_input_format` setting](../../operations/settings/settings.md#settings-date_time_input_format)
+-   [The `date_time_output_format` setting](../../operations/settings/settings.md#settings-date_time_output_format)
+-   [The `timezone` server configuration parameter](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone)
+-   [Operators for working with dates and times](../../sql-reference/operators/index.md#operators-datetime)
+-   [`Date` data type](../../sql-reference/data-types/date.md)
+-   [`DateTime` data type](../../sql-reference/data-types/datetime.md)
diff --git a/docs/en/reference/sql-reference/data-types/decimal.md b/docs/en/reference/sql-reference/data-types/decimal.md
new file mode 100644
index 00000000000..33b4addb54f
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/decimal.md
@@ -0,0 +1,114 @@
+---
+sidebar_position: 42
+sidebar_label: Decimal
+---
+
+# Decimal(P, S), Decimal32(S), Decimal64(S), Decimal128(S), Decimal256(S) {#decimal}
+
+Signed fixed-point numbers that keep precision during add, subtract and multiply operations. For division least significant digits are discarded (not rounded).
+
+## Parameters {#parameters}
+
+-   P - precision. Valid range: \[ 1 : 76 \]. Determines how many decimal digits number can have (including fraction).
+-   S - scale. Valid range: \[ 0 : P \]. Determines how many decimal digits fraction can have.
+
+Depending on P parameter value Decimal(P, S) is a synonym for:
+- P from \[ 1 : 9 \] - for Decimal32(S)
+- P from \[ 10 : 18 \] - for Decimal64(S)
+- P from \[ 19 : 38 \] - for Decimal128(S)
+- P from \[ 39 : 76 \] - for Decimal256(S)
+
+## Decimal Value Ranges {#decimal-value-ranges}
+
+-   Decimal32(S) - ( -1 \* 10^(9 - S), 1 \* 10^(9 - S) )
+-   Decimal64(S) - ( -1 \* 10^(18 - S), 1 \* 10^(18 - S) )
+-   Decimal128(S) - ( -1 \* 10^(38 - S), 1 \* 10^(38 - S) )
+-   Decimal256(S) - ( -1 \* 10^(76 - S), 1 \* 10^(76 - S) )
+
+For example, Decimal32(4) can contain numbers from -99999.9999 to 99999.9999 with 0.0001 step.
+
+## Internal Representation {#internal-representation}
+
+Internally data is represented as normal signed integers with respective bit width. Real value ranges that can be stored in memory are a bit larger than specified above, which are checked only on conversion from a string.
+
+Because modern CPUs do not support 128-bit integers natively, operations on Decimal128 are emulated. Because of this Decimal128 works significantly slower than Decimal32/Decimal64.
+
+## Operations and Result Type {#operations-and-result-type}
+
+Binary operations on Decimal result in wider result type (with any order of arguments).
+
+-   `Decimal64(S1) <op> Decimal32(S2) -> Decimal64(S)`
+-   `Decimal128(S1) <op> Decimal32(S2) -> Decimal128(S)`
+-   `Decimal128(S1) <op> Decimal64(S2) -> Decimal128(S)`
+-   `Decimal256(S1) <op> Decimal<32|64|128>(S2) -> Decimal256(S)`
+
+Rules for scale:
+
+-   add, subtract: S = max(S1, S2).
+-   multuply: S = S1 + S2.
+-   divide: S = S1.
+
+For similar operations between Decimal and integers, the result is Decimal of the same size as an argument.
+
+Operations between Decimal and Float32/Float64 are not defined. If you need them, you can explicitly cast one of argument using toDecimal32, toDecimal64, toDecimal128 or toFloat32, toFloat64 builtins. Keep in mind that the result will lose precision and type conversion is a computationally expensive operation.
+
+Some functions on Decimal return result as Float64 (for example, var or stddev). Intermediate calculations might still be performed in Decimal, which might lead to different results between Float64 and Decimal inputs with the same values.
+
+## Overflow Checks {#overflow-checks}
+
+During calculations on Decimal, integer overflows might happen. Excessive digits in a fraction are discarded (not rounded). Excessive digits in integer part will lead to an exception.
+
+``` sql
+SELECT toDecimal32(2, 4) AS x, x / 3
+```
+
+``` text
+┌──────x─┬─divide(toDecimal32(2, 4), 3)─┐
+│ 2.0000 │                       0.6666 │
+└────────┴──────────────────────────────┘
+```
+
+``` sql
+SELECT toDecimal32(4.2, 8) AS x, x * x
+```
+
+``` text
+DB::Exception: Scale is out of bounds.
+```
+
+``` sql
+SELECT toDecimal32(4.2, 8) AS x, 6 * x
+```
+
+``` text
+DB::Exception: Decimal math overflow.
+```
+
+Overflow checks lead to operations slowdown. If it is known that overflows are not possible, it makes sense to disable checks using `decimal_check_overflow` setting. When checks are disabled and overflow happens, the result will be incorrect:
+
+``` sql
+SET decimal_check_overflow = 0;
+SELECT toDecimal32(4.2, 8) AS x, 6 * x
+```
+
+``` text
+┌──────────x─┬─multiply(6, toDecimal32(4.2, 8))─┐
+│ 4.20000000 │                     -17.74967296 │
+└────────────┴──────────────────────────────────┘
+```
+
+Overflow checks happen not only on arithmetic operations but also on value comparison:
+
+``` sql
+SELECT toDecimal32(1, 8) < 100
+```
+
+``` text
+DB::Exception: Can't compare.
+```
+
+**See also**
+-   [isDecimalOverflow](../../sql-reference/functions/other-functions.md#is-decimal-overflow)
+-   [countDigits](../../sql-reference/functions/other-functions.md#count-digits)
+
+[Original article](https://clickhouse.com/docs/en/data_types/decimal/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/domains/index.md b/docs/en/reference/sql-reference/data-types/domains/index.md
new file mode 100644
index 00000000000..e27bf9a6d37
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/domains/index.md
@@ -0,0 +1,30 @@
+---
+sidebar_position: 56
+sidebar_label: Domains
+---
+
+# Domains {#domains}
+
+Domains are special-purpose types that add some extra features atop of existing base type, but leaving on-wire and on-disc format of the underlying data type intact. At the moment, ClickHouse does not support user-defined domains.
+
+You can use domains anywhere corresponding base type can be used, for example:
+
+-   Create a column of a domain type
+-   Read/write values from/to domain column
+-   Use it as an index if a base type can be used as an index
+-   Call functions with values of domain column
+
+### Extra Features of Domains {#extra-features-of-domains}
+
+-   Explicit column type name in `SHOW CREATE TABLE` or `DESCRIBE TABLE`
+-   Input from human-friendly format with `INSERT INTO domain_table(domain_column) VALUES(...)`
+-   Output to human-friendly format for `SELECT domain_column FROM domain_table`
+-   Loading data from an external source in the human-friendly format: `INSERT INTO domain_table FORMAT CSV ...`
+
+### Limitations {#limitations}
+
+-   Can’t convert index column of base type to domain type via `ALTER TABLE`.
+-   Can’t implicitly convert string values into domain values when inserting data from another column or table.
+-   Domain adds no constrains on stored values.
+
+[Original article](https://clickhouse.com/docs/en/data_types/domains/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/domains/ipv4.md b/docs/en/reference/sql-reference/data-types/domains/ipv4.md
new file mode 100644
index 00000000000..76d285fe34a
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/domains/ipv4.md
@@ -0,0 +1,82 @@
+---
+sidebar_position: 59
+sidebar_label: IPv4
+---
+
+## IPv4 {#ipv4}
+
+`IPv4` is a domain based on `UInt32` type and serves as a typed replacement for storing IPv4 values. It provides compact storage with the human-friendly input-output format and column type information on inspection.
+
+### Basic Usage {#basic-usage}
+
+``` sql
+CREATE TABLE hits (url String, from IPv4) ENGINE = MergeTree() ORDER BY url;
+
+DESCRIBE TABLE hits;
+```
+
+``` text
+┌─name─┬─type───┬─default_type─┬─default_expression─┬─comment─┬─codec_expression─┐
+│ url  │ String │              │                    │         │                  │
+│ from │ IPv4   │              │                    │         │                  │
+└──────┴────────┴──────────────┴────────────────────┴─────────┴──────────────────┘
+```
+
+OR you can use IPv4 domain as a key:
+
+``` sql
+CREATE TABLE hits (url String, from IPv4) ENGINE = MergeTree() ORDER BY from;
+```
+
+`IPv4` domain supports custom input format as IPv4-strings:
+
+``` sql
+INSERT INTO hits (url, from) VALUES ('https://wikipedia.org', '116.253.40.133')('https://clickhouse.com', '183.247.232.58')('https://clickhouse.com/docs/en/', '116.106.34.242');
+
+SELECT * FROM hits;
+```
+
+``` text
+┌─url────────────────────────────────┬───────────from─┐
+│ https://clickhouse.com/docs/en/ │ 116.106.34.242 │
+│ https://wikipedia.org              │ 116.253.40.133 │
+│ https://clickhouse.com          │ 183.247.232.58 │
+└────────────────────────────────────┴────────────────┘
+```
+
+Values are stored in compact binary form:
+
+``` sql
+SELECT toTypeName(from), hex(from) FROM hits LIMIT 1;
+```
+
+``` text
+┌─toTypeName(from)─┬─hex(from)─┐
+│ IPv4             │ B7F7E83A  │
+└──────────────────┴───────────┘
+```
+
+Domain values are not implicitly convertible to types other than `UInt32`.
+If you want to convert `IPv4` value to a string, you have to do that explicitly with `IPv4NumToString()` function:
+
+``` sql
+SELECT toTypeName(s), IPv4NumToString(from) as s FROM hits LIMIT 1;
+```
+
+    ┌─toTypeName(IPv4NumToString(from))─┬─s──────────────┐
+    │ String                            │ 183.247.232.58 │
+    └───────────────────────────────────┴────────────────┘
+
+Or cast to a `UInt32` value:
+
+``` sql
+SELECT toTypeName(i), CAST(from as UInt32) as i FROM hits LIMIT 1;
+```
+
+``` text
+┌─toTypeName(CAST(from, 'UInt32'))─┬──────────i─┐
+│ UInt32                           │ 3086477370 │
+└──────────────────────────────────┴────────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/data_types/domains/ipv4) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/domains/ipv6.md b/docs/en/reference/sql-reference/data-types/domains/ipv6.md
new file mode 100644
index 00000000000..c5745dcb80f
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/domains/ipv6.md
@@ -0,0 +1,84 @@
+---
+sidebar_position: 60
+sidebar_label: IPv6
+---
+
+## IPv6 {#ipv6}
+
+`IPv6` is a domain based on `FixedString(16)` type and serves as a typed replacement for storing IPv6 values. It provides compact storage with the human-friendly input-output format and column type information on inspection.
+
+### Basic Usage {#basic-usage}
+
+``` sql
+CREATE TABLE hits (url String, from IPv6) ENGINE = MergeTree() ORDER BY url;
+
+DESCRIBE TABLE hits;
+```
+
+``` text
+┌─name─┬─type───┬─default_type─┬─default_expression─┬─comment─┬─codec_expression─┐
+│ url  │ String │              │                    │         │                  │
+│ from │ IPv6   │              │                    │         │                  │
+└──────┴────────┴──────────────┴────────────────────┴─────────┴──────────────────┘
+```
+
+OR you can use `IPv6` domain as a key:
+
+``` sql
+CREATE TABLE hits (url String, from IPv6) ENGINE = MergeTree() ORDER BY from;
+```
+
+`IPv6` domain supports custom input as IPv6-strings:
+
+``` sql
+INSERT INTO hits (url, from) VALUES ('https://wikipedia.org', '2a02:aa08:e000:3100::2')('https://clickhouse.com', '2001:44c8:129:2632:33:0:252:2')('https://clickhouse.com/docs/en/', '2a02:e980:1e::1');
+
+SELECT * FROM hits;
+```
+
+``` text
+┌─url────────────────────────────────┬─from──────────────────────────┐
+│ https://clickhouse.com          │ 2001:44c8:129:2632:33:0:252:2 │
+│ https://clickhouse.com/docs/en/ │ 2a02:e980:1e::1               │
+│ https://wikipedia.org              │ 2a02:aa08:e000:3100::2        │
+└────────────────────────────────────┴───────────────────────────────┘
+```
+
+Values are stored in compact binary form:
+
+``` sql
+SELECT toTypeName(from), hex(from) FROM hits LIMIT 1;
+```
+
+``` text
+┌─toTypeName(from)─┬─hex(from)────────────────────────┐
+│ IPv6             │ 200144C8012926320033000002520002 │
+└──────────────────┴──────────────────────────────────┘
+```
+
+Domain values are not implicitly convertible to types other than `FixedString(16)`.
+If you want to convert `IPv6` value to a string, you have to do that explicitly with `IPv6NumToString()` function:
+
+``` sql
+SELECT toTypeName(s), IPv6NumToString(from) as s FROM hits LIMIT 1;
+```
+
+``` text
+┌─toTypeName(IPv6NumToString(from))─┬─s─────────────────────────────┐
+│ String                            │ 2001:44c8:129:2632:33:0:252:2 │
+└───────────────────────────────────┴───────────────────────────────┘
+```
+
+Or cast to a `FixedString(16)` value:
+
+``` sql
+SELECT toTypeName(i), CAST(from as FixedString(16)) as i FROM hits LIMIT 1;
+```
+
+``` text
+┌─toTypeName(CAST(from, 'FixedString(16)'))─┬─i───────┐
+│ FixedString(16)                           │  ��� │
+└───────────────────────────────────────────┴─────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/data_types/domains/ipv6) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/enum.md b/docs/en/reference/sql-reference/data-types/enum.md
new file mode 100644
index 00000000000..5dbec255da6
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/enum.md
@@ -0,0 +1,130 @@
+---
+sidebar_position: 50
+sidebar_label: Enum
+---
+
+# Enum {#enum}
+
+Enumerated type consisting of named values.
+
+Named values must be declared as `'string' = integer` pairs. ClickHouse stores only numbers, but supports operations with the values through their names.
+
+ClickHouse supports:
+
+-   8-bit `Enum`. It can contain up to 256 values enumerated in the `[-128, 127]` range.
+-   16-bit `Enum`. It can contain up to 65536 values enumerated in the `[-32768, 32767]` range.
+
+ClickHouse automatically chooses the type of `Enum` when data is inserted. You can also use `Enum8` or `Enum16` types to be sure in the size of storage.
+
+## Usage Examples {#usage-examples}
+
+Here we create a table with an `Enum8('hello' = 1, 'world' = 2)` type column:
+
+``` sql
+CREATE TABLE t_enum
+(
+    x Enum('hello' = 1, 'world' = 2)
+)
+ENGINE = TinyLog
+```
+
+Column `x` can only store values that are listed in the type definition: `'hello'` or `'world'`. If you try to save any other value, ClickHouse will raise an exception. 8-bit size for this `Enum` is chosen automatically.
+
+``` sql
+INSERT INTO t_enum VALUES ('hello'), ('world'), ('hello')
+```
+
+``` text
+Ok.
+```
+
+``` sql
+INSERT INTO t_enum values('a')
+```
+
+``` text
+Exception on client:
+Code: 49. DB::Exception: Unknown element 'a' for type Enum('hello' = 1, 'world' = 2)
+```
+
+When you query data from the table, ClickHouse outputs the string values from `Enum`.
+
+``` sql
+SELECT * FROM t_enum
+```
+
+``` text
+┌─x─────┐
+│ hello │
+│ world │
+│ hello │
+└───────┘
+```
+
+If you need to see the numeric equivalents of the rows, you must cast the `Enum` value to integer type.
+
+``` sql
+SELECT CAST(x, 'Int8') FROM t_enum
+```
+
+``` text
+┌─CAST(x, 'Int8')─┐
+│               1 │
+│               2 │
+│               1 │
+└─────────────────┘
+```
+
+To create an Enum value in a query, you also need to use `CAST`.
+
+``` sql
+SELECT toTypeName(CAST('a', 'Enum(\'a\' = 1, \'b\' = 2)'))
+```
+
+``` text
+┌─toTypeName(CAST('a', 'Enum(\'a\' = 1, \'b\' = 2)'))─┐
+│ Enum8('a' = 1, 'b' = 2)                             │
+└─────────────────────────────────────────────────────┘
+```
+
+## General Rules and Usage {#general-rules-and-usage}
+
+Each of the values is assigned a number in the range `-128 ... 127` for `Enum8` or in the range `-32768 ... 32767` for `Enum16`. All the strings and numbers must be different. An empty string is allowed. If this type is specified (in a table definition), numbers can be in an arbitrary order. However, the order does not matter.
+
+Neither the string nor the numeric value in an `Enum` can be [NULL](../../sql-reference/syntax.md).
+
+An `Enum` can be contained in [Nullable](../../sql-reference/data-types/nullable.md) type. So if you create a table using the query
+
+``` sql
+CREATE TABLE t_enum_nullable
+(
+    x Nullable( Enum8('hello' = 1, 'world' = 2) )
+)
+ENGINE = TinyLog
+```
+
+it can store not only `'hello'` and `'world'`, but `NULL`, as well.
+
+``` sql
+INSERT INTO t_enum_nullable Values('hello'),('world'),(NULL)
+```
+
+In RAM, an `Enum` column is stored in the same way as `Int8` or `Int16` of the corresponding numerical values.
+
+When reading in text form, ClickHouse parses the value as a string and searches for the corresponding string from the set of Enum values. If it is not found, an exception is thrown. When reading in text format, the string is read and the corresponding numeric value is looked up. An exception will be thrown if it is not found.
+When writing in text form, it writes the value as the corresponding string. If column data contains garbage (numbers that are not from the valid set), an exception is thrown. When reading and writing in binary form, it works the same way as for Int8 and Int16 data types.
+The implicit default value is the value with the lowest number.
+
+During `ORDER BY`, `GROUP BY`, `IN`, `DISTINCT` and so on, Enums behave the same way as the corresponding numbers. For example, ORDER BY sorts them numerically. Equality and comparison operators work the same way on Enums as they do on the underlying numeric values.
+
+Enum values cannot be compared with numbers. Enums can be compared to a constant string. If the string compared to is not a valid value for the Enum, an exception will be thrown. The IN operator is supported with the Enum on the left-hand side and a set of strings on the right-hand side. The strings are the values of the corresponding Enum.
+
+Most numeric and string operations are not defined for Enum values, e.g. adding a number to an Enum or concatenating a string to an Enum.
+However, the Enum has a natural `toString` function that returns its string value.
+
+Enum values are also convertible to numeric types using the `toT` function, where T is a numeric type. When T corresponds to the enum’s underlying numeric type, this conversion is zero-cost.
+The Enum type can be changed without cost using ALTER, if only the set of values is changed. It is possible to both add and remove members of the Enum using ALTER (removing is safe only if the removed value has never been used in the table). As a safeguard, changing the numeric value of a previously defined Enum member will throw an exception.
+
+Using ALTER, it is possible to change an Enum8 to an Enum16 or vice versa, just like changing an Int8 to Int16.
+
+[Original article](https://clickhouse.com/docs/en/data_types/enum/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/fixedstring.md b/docs/en/reference/sql-reference/data-types/fixedstring.md
new file mode 100644
index 00000000000..230792c19bb
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/fixedstring.md
@@ -0,0 +1,61 @@
+---
+sidebar_position: 45
+sidebar_label: FixedString(N)
+---
+
+# Fixedstring {#fixedstring}
+
+A fixed-length string of `N` bytes (neither characters nor code points).
+
+To declare a column of `FixedString` type, use the following syntax:
+
+``` sql
+<column_name> FixedString(N)
+```
+
+Where `N` is a natural number.
+
+The `FixedString` type is efficient when data has the length of precisely `N` bytes. In all other cases, it is likely to reduce efficiency.
+
+Examples of the values that can be efficiently stored in `FixedString`-typed columns:
+
+-   The binary representation of IP addresses (`FixedString(16)` for IPv6).
+-   Language codes (ru_RU, en_US … ).
+-   Currency codes (USD, RUB … ).
+-   Binary representation of hashes (`FixedString(16)` for MD5, `FixedString(32)` for SHA256).
+
+To store UUID values, use the [UUID](../../sql-reference/data-types/uuid.md) data type.
+
+When inserting the data, ClickHouse:
+
+-   Complements a string with null bytes if the string contains fewer than `N` bytes.
+-   Throws the `Too large value for FixedString(N)` exception if the string contains more than `N` bytes.
+
+When selecting the data, ClickHouse does not remove the null bytes at the end of the string. If you use the `WHERE` clause, you should add null bytes manually to match the `FixedString` value. The following example illustrates how to use the `WHERE` clause with `FixedString`.
+
+Let’s consider the following table with the single `FixedString(2)` column:
+
+``` text
+┌─name──┐
+│ b     │
+└───────┘
+```
+
+The query `SELECT * FROM FixedStringTable WHERE a = 'b'` does not return any data as a result. We should complement the filter pattern with null bytes.
+
+``` sql
+SELECT * FROM FixedStringTable
+WHERE a = 'b\0'
+```
+
+``` text
+┌─a─┐
+│ b │
+└───┘
+```
+
+This behaviour differs from MySQL for the `CHAR` type (where strings are padded with spaces, and the spaces are removed for output).
+
+Note that the length of the `FixedString(N)` value is constant. The [length](../../sql-reference/functions/array-functions.md#array_functions-length) function returns `N` even if the `FixedString(N)` value is filled only with null bytes, but the [empty](../../sql-reference/functions/string-functions.md#empty) function returns `1` in this case.
+
+[Original article](https://clickhouse.com/docs/en/data_types/fixedstring/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/float.md b/docs/en/reference/sql-reference/data-types/float.md
new file mode 100644
index 00000000000..46076e29525
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/float.md
@@ -0,0 +1,92 @@
+---
+sidebar_position: 41
+sidebar_label: Float32, Float64
+---
+
+# Float32, Float64 {#float32-float64}
+
+[Floating point numbers](https://en.wikipedia.org/wiki/IEEE_754).
+
+Types are equivalent to types of C:
+
+-   `Float32` — `float`.
+-   `Float64` — `double`.
+
+We recommend that you store data in integer form whenever possible. For example, convert fixed precision numbers to integer values, such as monetary amounts or page load times in milliseconds.
+
+Aliases:
+
+-   `Float32` — `FLOAT`.
+-   `Float64` — `DOUBLE`.
+
+When creating tables, numeric parameters for floating point numbers can be set (e.g. `FLOAT(12)`, `FLOAT(15, 22)`, `DOUBLE(12)`, `DOUBLE(4, 18)`), but ClickHouse ignores them.
+
+## Using Floating-point Numbers {#using-floating-point-numbers}
+
+-   Computations with floating-point numbers might produce a rounding error.
+
+<!-- -->
+
+``` sql
+SELECT 1 - 0.9
+```
+
+``` text
+┌───────minus(1, 0.9)─┐
+│ 0.09999999999999998 │
+└─────────────────────┘
+```
+
+-   The result of the calculation depends on the calculation method (the processor type and architecture of the computer system).
+-   Floating-point calculations might result in numbers such as infinity (`Inf`) and “not-a-number” (`NaN`). This should be taken into account when processing the results of calculations.
+-   When parsing floating-point numbers from text, the result might not be the nearest machine-representable number.
+
+## NaN and Inf {#data_type-float-nan-inf}
+
+In contrast to standard SQL, ClickHouse supports the following categories of floating-point numbers:
+
+-   `Inf` – Infinity.
+
+<!-- -->
+
+``` sql
+SELECT 0.5 / 0
+```
+
+``` text
+┌─divide(0.5, 0)─┐
+│            inf │
+└────────────────┘
+```
+
+-   `-Inf` — Negative infinity.
+
+<!-- -->
+
+``` sql
+SELECT -0.5 / 0
+```
+
+``` text
+┌─divide(-0.5, 0)─┐
+│            -inf │
+└─────────────────┘
+```
+
+-   `NaN` — Not a number.
+
+<!-- -->
+
+``` sql
+SELECT 0 / 0
+```
+
+``` text
+┌─divide(0, 0)─┐
+│          nan │
+└──────────────┘
+```
+
+See the rules for `NaN` sorting in the section [ORDER BY clause](../../sql-reference/statements/select/order-by.md).
+
+[Original article](https://clickhouse.com/docs/en/data_types/float/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/geo.md b/docs/en/reference/sql-reference/data-types/geo.md
new file mode 100644
index 00000000000..7ce863a5a10
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/geo.md
@@ -0,0 +1,107 @@
+---
+sidebar_position: 62
+sidebar_label: Geo
+---
+
+# Geo Data Types {#geo-data-types}
+
+ClickHouse supports data types for representing geographical objects — locations, lands, etc.
+
+:::warning    
+Currently geo data types are an experimental feature. To work with them you must set `allow_experimental_geo_types = 1`.
+:::
+
+**See Also**
+- [Representing simple geographical features](https://en.wikipedia.org/wiki/GeoJSON).
+- [allow_experimental_geo_types](../../operations/settings/settings.md#allow-experimental-geo-types) setting.
+
+## Point {#point-data-type}
+
+`Point` is represented by its X and Y coordinates, stored as a [Tuple](tuple.md)([Float64](float.md), [Float64](float.md)).
+
+**Example**
+
+Query:
+
+```sql
+SET allow_experimental_geo_types = 1;
+CREATE TABLE geo_point (p Point) ENGINE = Memory();
+INSERT INTO geo_point VALUES((10, 10));
+SELECT p, toTypeName(p) FROM geo_point;
+```
+Result:
+
+``` text
+┌─p─────┬─toTypeName(p)─┐
+│ (10,10) │ Point         │
+└───────┴───────────────┘
+```
+
+## Ring {#ring-data-type}
+
+`Ring` is a simple polygon without holes stored as an array of points: [Array](array.md)([Point](#point-data-type)).
+
+**Example**
+
+Query:
+
+```sql
+SET allow_experimental_geo_types = 1;
+CREATE TABLE geo_ring (r Ring) ENGINE = Memory();
+INSERT INTO geo_ring VALUES([(0, 0), (10, 0), (10, 10), (0, 10)]);
+SELECT r, toTypeName(r) FROM geo_ring;
+```
+Result:
+
+``` text
+┌─r─────────────────────────────┬─toTypeName(r)─┐
+│ [(0,0),(10,0),(10,10),(0,10)] │ Ring          │
+└───────────────────────────────┴───────────────┘
+```
+
+## Polygon {#polygon-data-type}
+
+`Polygon` is a polygon with holes stored as an array of rings: [Array](array.md)([Ring](#ring-data-type)). First element of outer array is the outer shape of polygon and all the following elements are holes.
+
+**Example**
+
+This is a polygon with one hole:
+
+```sql
+SET allow_experimental_geo_types = 1;
+CREATE TABLE geo_polygon (pg Polygon) ENGINE = Memory();
+INSERT INTO geo_polygon VALUES([[(20, 20), (50, 20), (50, 50), (20, 50)], [(30, 30), (50, 50), (50, 30)]]);
+SELECT pg, toTypeName(pg) FROM geo_polygon;
+```
+
+Result:
+
+``` text
+┌─pg────────────────────────────────────────────────────────────┬─toTypeName(pg)─┐
+│ [[(20,20),(50,20),(50,50),(20,50)],[(30,30),(50,50),(50,30)]] │ Polygon        │
+└───────────────────────────────────────────────────────────────┴────────────────┘
+```
+
+## MultiPolygon {#multipolygon-data-type}
+
+`MultiPolygon` consists of multiple polygons and is stored as an array of polygons: [Array](array.md)([Polygon](#polygon-data-type)).
+
+**Example**
+
+This multipolygon consists of two separate polygons — the first one without holes, and the second with one hole:
+
+```sql
+SET allow_experimental_geo_types = 1;
+CREATE TABLE geo_multipolygon (mpg MultiPolygon) ENGINE = Memory();
+INSERT INTO geo_multipolygon VALUES([[[(0, 0), (10, 0), (10, 10), (0, 10)]], [[(20, 20), (50, 20), (50, 50), (20, 50)],[(30, 30), (50, 50), (50, 30)]]]);
+SELECT mpg, toTypeName(mpg) FROM geo_multipolygon;
+```
+Result:
+
+``` text
+┌─mpg─────────────────────────────────────────────────────────────────────────────────────────────┬─toTypeName(mpg)─┐
+│ [[[(0,0),(10,0),(10,10),(0,10)]],[[(20,20),(50,20),(50,50),(20,50)],[(30,30),(50,50),(50,30)]]] │ MultiPolygon    │
+└─────────────────────────────────────────────────────────────────────────────────────────────────┴─────────────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/data-types/geo/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/index.md b/docs/en/reference/sql-reference/data-types/index.md
new file mode 100644
index 00000000000..ca26b89ec87
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/index.md
@@ -0,0 +1,14 @@
+---
+sidebar_label: Data Types
+sidebar_position: 37
+---
+
+# Data Types 
+
+ClickHouse can store various kinds of data in table cells.
+
+This section describes the supported data types and special considerations for using and/or implementing them if any.
+
+You can check whether data type name is case-sensitive in the [system.data_type_families](../../operations/system-tables/data_type_families.md#system_tables-data_type_families) table.
+
+[Original article](https://clickhouse.com/docs/en/data_types/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/int-uint.md b/docs/en/reference/sql-reference/data-types/int-uint.md
new file mode 100644
index 00000000000..86d587cfb55
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/int-uint.md
@@ -0,0 +1,37 @@
+---
+sidebar_position: 40
+sidebar_label: UInt8, UInt16, UInt32, UInt64, UInt128, UInt256, Int8, Int16, Int32, Int64, Int128, Int256
+---
+
+# UInt8, UInt16, UInt32, UInt64, UInt128, UInt256, Int8, Int16, Int32, Int64, Int128, Int256
+
+Fixed-length integers, with or without a sign.
+
+When creating tables, numeric parameters for integer numbers can be set (e.g. `TINYINT(8)`, `SMALLINT(16)`, `INT(32)`, `BIGINT(64)`), but ClickHouse ignores them.
+
+## Int Ranges {#int-ranges}
+
+-   `Int8` — \[-128 : 127\]
+-   `Int16` — \[-32768 : 32767\]
+-   `Int32` — \[-2147483648 : 2147483647\]
+-   `Int64` — \[-9223372036854775808 : 9223372036854775807\]
+-   `Int128` — \[-170141183460469231731687303715884105728 : 170141183460469231731687303715884105727\]
+-   `Int256` — \[-57896044618658097711785492504343953926634992332820282019728792003956564819968 : 57896044618658097711785492504343953926634992332820282019728792003956564819967\]
+
+Aliases:
+
+-   `Int8` — `TINYINT`, `BOOL`, `BOOLEAN`, `INT1`.
+-   `Int16` — `SMALLINT`, `INT2`.
+-   `Int32` — `INT`, `INT4`, `INTEGER`.
+-   `Int64` — `BIGINT`.
+
+## UInt Ranges {#uint-ranges}
+
+-   `UInt8` — \[0 : 255\]
+-   `UInt16` — \[0 : 65535\]
+-   `UInt32` — \[0 : 4294967295\]
+-   `UInt64` — \[0 : 18446744073709551615\]
+-   `UInt128` — \[0 : 340282366920938463463374607431768211455\]
+-   `UInt256` — \[0 : 115792089237316195423570985008687907853269984665640564039457584007913129639935\]
+
+[Original article](https://clickhouse.com/docs/en/data_types/int_uint/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/lowcardinality.md b/docs/en/reference/sql-reference/data-types/lowcardinality.md
new file mode 100644
index 00000000000..40105446cbe
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/lowcardinality.md
@@ -0,0 +1,59 @@
+---
+sidebar_position: 51
+sidebar_label: LowCardinality
+---
+
+# LowCardinality Data Type {#lowcardinality-data-type}
+
+Changes the internal representation of other data types to be dictionary-encoded.
+
+## Syntax {#lowcardinality-syntax}
+
+``` sql
+LowCardinality(data_type)
+```
+
+**Parameters**
+
+-   `data_type` — [String](../../sql-reference/data-types/string.md), [FixedString](../../sql-reference/data-types/fixedstring.md), [Date](../../sql-reference/data-types/date.md), [DateTime](../../sql-reference/data-types/datetime.md), and numbers excepting [Decimal](../../sql-reference/data-types/decimal.md). `LowCardinality` is not efficient for some data types, see the [allow_suspicious_low_cardinality_types](../../operations/settings/settings.md#allow_suspicious_low_cardinality_types) setting description.
+
+## Description {#lowcardinality-dscr}
+
+`LowCardinality` is a superstructure that changes a data storage method and rules of data processing. ClickHouse applies [dictionary coding](https://en.wikipedia.org/wiki/Dictionary_coder) to `LowCardinality`-columns. Operating with dictionary encoded data significantly increases performance of [SELECT](../../sql-reference/statements/select/index.md) queries for many applications.
+
+The efficiency of using `LowCardinality` data type depends on data diversity. If a dictionary contains less than 10,000 distinct values, then ClickHouse mostly shows higher efficiency of data reading and storing. If a dictionary contains more than 100,000 distinct values, then ClickHouse can perform worse in comparison with using ordinary data types.
+
+Consider using `LowCardinality` instead of [Enum](../../sql-reference/data-types/enum.md) when working with strings. `LowCardinality` provides more flexibility in use and often reveals the same or higher efficiency.
+
+## Example {#example}
+
+Create a table with a `LowCardinality`-column:
+
+``` sql
+CREATE TABLE lc_t
+(
+    `id` UInt16,
+    `strings` LowCardinality(String)
+)
+ENGINE = MergeTree()
+ORDER BY id
+```
+
+## Related Settings and Functions {#related-settings-and-functions}
+
+Settings:
+
+-   [low_cardinality_max_dictionary_size](../../operations/settings/settings.md#low_cardinality_max_dictionary_size)
+-   [low_cardinality_use_single_dictionary_for_part](../../operations/settings/settings.md#low_cardinality_use_single_dictionary_for_part)
+-   [low_cardinality_allow_in_native_format](../../operations/settings/settings.md#low_cardinality_allow_in_native_format)
+-   [allow_suspicious_low_cardinality_types](../../operations/settings/settings.md#allow_suspicious_low_cardinality_types)
+-   [output_format_arrow_low_cardinality_as_dictionary](../../operations/settings/settings.md#output-format-arrow-low-cardinality-as-dictionary)
+
+Functions:
+
+-   [toLowCardinality](../../sql-reference/functions/type-conversion-functions.md#tolowcardinality)
+
+## See Also {#see-also}
+
+-   [Reducing ClickHouse Storage Cost with the Low Cardinality Type – Lessons from an Instana Engineer](https://www.instana.com/blog/reducing-clickhouse-storage-cost-with-the-low-cardinality-type-lessons-from-an-instana-engineer/).
+-   [String Optimization (video presentation in Russian)](https://youtu.be/rqf-ILRgBdY?list=PL0Z2YDlm0b3iwXCpEFiOOYmwXzVmjJfEt). [Slides in English](https://github.com/ClickHouse/clickhouse-presentations/raw/master/meetup19/string_optimization.pdf).
diff --git a/docs/en/reference/sql-reference/data-types/map.md b/docs/en/reference/sql-reference/data-types/map.md
new file mode 100644
index 00000000000..56f4442fe5a
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/map.md
@@ -0,0 +1,111 @@
+---
+sidebar_position: 65
+sidebar_label: Map(key, value)
+---
+
+# Map(key, value) {#data_type-map}
+
+`Map(key, value)` data type stores `key:value` pairs.
+
+**Parameters**
+
+-   `key` — The key part of the pair. [String](../../sql-reference/data-types/string.md), [Integer](../../sql-reference/data-types/int-uint.md), [LowCardinality](../../sql-reference/data-types/lowcardinality.md), or [FixedString](../../sql-reference/data-types/fixedstring.md).
+-   `value` — The value part of the pair. [String](../../sql-reference/data-types/string.md), [Integer](../../sql-reference/data-types/int-uint.md), [Array](../../sql-reference/data-types/array.md), [LowCardinality](../../sql-reference/data-types/lowcardinality.md), or [FixedString](../../sql-reference/data-types/fixedstring.md).
+
+To get the value from an `a Map('key', 'value')` column, use `a['key']` syntax. This lookup works now with a linear complexity.
+
+**Examples**
+
+Consider the table:
+
+``` sql
+CREATE TABLE table_map (a Map(String, UInt64)) ENGINE=Memory;
+INSERT INTO table_map VALUES ({'key1':1, 'key2':10}), ({'key1':2,'key2':20}), ({'key1':3,'key2':30});
+```
+
+Select all `key2` values:
+
+```sql
+SELECT a['key2'] FROM table_map;
+```
+Result:
+
+```text
+┌─arrayElement(a, 'key2')─┐
+│                      10 │
+│                      20 │
+│                      30 │
+└─────────────────────────┘
+```
+
+If there's no such `key` in the `Map()` column, the query returns zeros for numerical values, empty strings or empty arrays.
+
+```sql
+INSERT INTO table_map VALUES ({'key3':100}), ({});
+SELECT a['key3'] FROM table_map;
+```
+
+Result:
+
+```text
+┌─arrayElement(a, 'key3')─┐
+│                     100 │
+│                       0 │
+└─────────────────────────┘
+┌─arrayElement(a, 'key3')─┐
+│                       0 │
+│                       0 │
+│                       0 │
+└─────────────────────────┘
+```
+
+## Convert Tuple to Map Type {#map-and-tuple}
+
+You can cast `Tuple()` as `Map()` using [CAST](../../sql-reference/functions/type-conversion-functions.md#type_conversion_function-cast) function:
+
+``` sql
+SELECT CAST(([1, 2, 3], ['Ready', 'Steady', 'Go']), 'Map(UInt8, String)') AS map;
+```
+
+``` text
+┌─map───────────────────────────┐
+│ {1:'Ready',2:'Steady',3:'Go'} │
+└───────────────────────────────┘
+```
+
+## Map.keys and Map.values Subcolumns {#map-subcolumns}
+
+To optimize `Map` column processing, in some cases you can use the `keys` and `values` subcolumns instead of reading the whole column.
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE t_map (`a` Map(String, UInt64)) ENGINE = Memory;
+
+INSERT INTO t_map VALUES (map('key1', 1, 'key2', 2, 'key3', 3));
+
+SELECT a.keys FROM t_map;
+
+SELECT a.values FROM t_map;
+```
+
+Result:
+
+``` text
+┌─a.keys─────────────────┐
+│ ['key1','key2','key3'] │
+└────────────────────────┘
+
+┌─a.values─┐
+│ [1,2,3]  │
+└──────────┘
+```
+
+**See Also**
+
+-   [map()](../../sql-reference/functions/tuple-map-functions.md#function-map) function
+-   [CAST()](../../sql-reference/functions/type-conversion-functions.md#type_conversion_function-cast) function
+
+[Original article](https://clickhouse.com/docs/en/data-types/map/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/multiword-types.md b/docs/en/reference/sql-reference/data-types/multiword-types.md
new file mode 100644
index 00000000000..ae57037b6e2
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/multiword-types.md
@@ -0,0 +1,29 @@
+---
+sidebar_position: 61
+sidebar_label: Multiword Type Names
+---
+
+# Multiword Types {#multiword-types}
+
+When creating tables, you can use data types with a name consisting of several words. This is implemented for better SQL compatibility.
+
+## Multiword Types Support {#multiword-types-support}
+
+| Multiword types                  | Simple types                                                 |
+|----------------------------------|--------------------------------------------------------------|
+| DOUBLE PRECISION                 | [Float64](../../sql-reference/data-types/float.md)           |
+| CHAR LARGE OBJECT                | [String](../../sql-reference/data-types/string.md)           |
+| CHAR VARYING                     | [String](../../sql-reference/data-types/string.md)           |
+| CHARACTER LARGE OBJECT           | [String](../../sql-reference/data-types/string.md)           |
+| CHARACTER VARYING                | [String](../../sql-reference/data-types/string.md)           |
+| NCHAR LARGE OBJECT               | [String](../../sql-reference/data-types/string.md)           |
+| NCHAR VARYING                    | [String](../../sql-reference/data-types/string.md)           |
+| NATIONAL CHARACTER LARGE OBJECT  | [String](../../sql-reference/data-types/string.md)           |
+| NATIONAL CHARACTER VARYING       | [String](../../sql-reference/data-types/string.md)           |
+| NATIONAL CHAR VARYING            | [String](../../sql-reference/data-types/string.md)           |
+| NATIONAL CHARACTER               | [String](../../sql-reference/data-types/string.md)           |
+| NATIONAL CHAR                    | [String](../../sql-reference/data-types/string.md)           |
+| BINARY LARGE OBJECT              | [String](../../sql-reference/data-types/string.md)           |
+| BINARY VARYING                   | [String](../../sql-reference/data-types/string.md)           |
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/data-types/multiword-types/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/nested-data-structures/index.md b/docs/en/reference/sql-reference/data-types/nested-data-structures/index.md
new file mode 100644
index 00000000000..c0f016ea41d
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/nested-data-structures/index.md
@@ -0,0 +1,8 @@
+---
+sidebar_label: Nested Data Structures
+sidebar_position: 54
+---
+
+# Nested Data Structures {#nested-data-structures}
+
+[Original article](https://clickhouse.com/docs/en/data_types/nested_data_structures/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/nested-data-structures/nested.md b/docs/en/reference/sql-reference/data-types/nested-data-structures/nested.md
new file mode 100644
index 00000000000..8258d8bd8e5
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/nested-data-structures/nested.md
@@ -0,0 +1,106 @@
+---
+sidebar_position: 57
+sidebar_label: Nested(Name1 Type1, Name2 Type2, ...)
+---
+
+# Nested {#nested}
+
+## Nested(name1 Type1, Name2 Type2, …) {#nestedname1-type1-name2-type2}
+
+A nested data structure is like a table inside a cell. The parameters of a nested data structure – the column names and types – are specified the same way as in a [CREATE TABLE](../../../sql-reference/statements/create/table.md) query. Each table row can correspond to any number of rows in a nested data structure.
+
+Example:
+
+``` sql
+CREATE TABLE test.visits
+(
+    CounterID UInt32,
+    StartDate Date,
+    Sign Int8,
+    IsNew UInt8,
+    VisitID UInt64,
+    UserID UInt64,
+    ...
+    Goals Nested
+    (
+        ID UInt32,
+        Serial UInt32,
+        EventTime DateTime,
+        Price Int64,
+        OrderID String,
+        CurrencyID UInt32
+    ),
+    ...
+) ENGINE = CollapsingMergeTree(StartDate, intHash32(UserID), (CounterID, StartDate, intHash32(UserID), VisitID), 8192, Sign)
+```
+
+This example declares the `Goals` nested data structure, which contains data about conversions (goals reached). Each row in the ‘visits’ table can correspond to zero or any number of conversions.
+
+When [flatten_nested](../../../operations/settings/settings.md#flatten-nested) is set to `0` (which is not by default), arbitrary levels of nesting are supported.
+
+In most cases, when working with a nested data structure, its columns are specified with column names separated by a dot. These columns make up an array of matching types. All the column arrays of a single nested data structure have the same length.
+
+Example:
+
+``` sql
+SELECT
+    Goals.ID,
+    Goals.EventTime
+FROM test.visits
+WHERE CounterID = 101500 AND length(Goals.ID) < 5
+LIMIT 10
+```
+
+``` text
+┌─Goals.ID───────────────────────┬─Goals.EventTime───────────────────────────────────────────────────────────────────────────┐
+│ [1073752,591325,591325]        │ ['2014-03-17 16:38:10','2014-03-17 16:38:48','2014-03-17 16:42:27']                       │
+│ [1073752]                      │ ['2014-03-17 00:28:25']                                                                   │
+│ [1073752]                      │ ['2014-03-17 10:46:20']                                                                   │
+│ [1073752,591325,591325,591325] │ ['2014-03-17 13:59:20','2014-03-17 22:17:55','2014-03-17 22:18:07','2014-03-17 22:18:51'] │
+│ []                             │ []                                                                                        │
+│ [1073752,591325,591325]        │ ['2014-03-17 11:37:06','2014-03-17 14:07:47','2014-03-17 14:36:21']                       │
+│ []                             │ []                                                                                        │
+│ []                             │ []                                                                                        │
+│ [591325,1073752]               │ ['2014-03-17 00:46:05','2014-03-17 00:46:05']                                             │
+│ [1073752,591325,591325,591325] │ ['2014-03-17 13:28:33','2014-03-17 13:30:26','2014-03-17 18:51:21','2014-03-17 18:51:45'] │
+└────────────────────────────────┴───────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+It is easiest to think of a nested data structure as a set of multiple column arrays of the same length.
+
+The only place where a SELECT query can specify the name of an entire nested data structure instead of individual columns is the ARRAY JOIN clause. For more information, see “ARRAY JOIN clause”. Example:
+
+``` sql
+SELECT
+    Goal.ID,
+    Goal.EventTime
+FROM test.visits
+ARRAY JOIN Goals AS Goal
+WHERE CounterID = 101500 AND length(Goals.ID) < 5
+LIMIT 10
+```
+
+``` text
+┌─Goal.ID─┬──────Goal.EventTime─┐
+│ 1073752 │ 2014-03-17 16:38:10 │
+│  591325 │ 2014-03-17 16:38:48 │
+│  591325 │ 2014-03-17 16:42:27 │
+│ 1073752 │ 2014-03-17 00:28:25 │
+│ 1073752 │ 2014-03-17 10:46:20 │
+│ 1073752 │ 2014-03-17 13:59:20 │
+│  591325 │ 2014-03-17 22:17:55 │
+│  591325 │ 2014-03-17 22:18:07 │
+│  591325 │ 2014-03-17 22:18:51 │
+│ 1073752 │ 2014-03-17 11:37:06 │
+└─────────┴─────────────────────┘
+```
+
+You can’t perform SELECT for an entire nested data structure. You can only explicitly list individual columns that are part of it.
+
+For an INSERT query, you should pass all the component column arrays of a nested data structure separately (as if they were individual column arrays). During insertion, the system checks that they have the same length.
+
+For a DESCRIBE query, the columns in a nested data structure are listed separately in the same way.
+
+The ALTER query for elements in a nested data structure has limitations.
+
+[Original article](https://clickhouse.com/docs/en/data_types/nested_data_structures/nested/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/nullable.md b/docs/en/reference/sql-reference/data-types/nullable.md
new file mode 100644
index 00000000000..f3c3dcd2326
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/nullable.md
@@ -0,0 +1,72 @@
+---
+sidebar_position: 55
+sidebar_label: Nullable
+---
+
+# Nullable(typename) {#data_type-nullable}
+
+Allows to store special marker ([NULL](../../sql-reference/syntax.md)) that denotes “missing value” alongside normal values allowed by `TypeName`. For example, a `Nullable(Int8)` type column can store `Int8` type values, and the rows that do not have a value will store `NULL`.
+
+For a `TypeName`, you can’t use composite data types [Array](../../sql-reference/data-types/array.md) and [Tuple](../../sql-reference/data-types/tuple.md). Composite data types can contain `Nullable` type values, such as `Array(Nullable(Int8))`.
+
+A `Nullable` type field can’t be included in table indexes.
+
+`NULL` is the default value for any `Nullable` type, unless specified otherwise in the ClickHouse server configuration.
+
+## Storage Features {#storage-features}
+
+To store `Nullable` type values in a table column, ClickHouse uses a separate file with `NULL` masks in addition to normal file with values. Entries in masks file allow ClickHouse to distinguish between `NULL` and a default value of corresponding data type for each table row. Because of an additional file, `Nullable` column consumes additional storage space compared to a similar normal one.
+
+:::note    
+Using `Nullable` almost always negatively affects performance, keep this in mind when designing your databases.
+:::
+
+## Finding NULL {#finding-null}
+
+It is possible to find `NULL` values in a column by using `null` subcolumn without reading the whole column. It returns `1` if the corresponding value is `NULL` and `0` otherwise.
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE nullable (`n` Nullable(UInt32)) ENGINE = MergeTree ORDER BY tuple();
+
+INSERT INTO nullable VALUES (1) (NULL) (2) (NULL);
+
+SELECT n.null FROM nullable;
+```
+
+Result:
+
+``` text
+┌─n.null─┐
+│      0 │
+│      1 │
+│      0 │
+│      1 │
+└────────┘
+```
+
+## Usage Example {#usage-example}
+
+``` sql
+CREATE TABLE t_null(x Int8, y Nullable(Int8)) ENGINE TinyLog
+```
+
+``` sql
+INSERT INTO t_null VALUES (1, NULL), (2, 3)
+```
+
+``` sql
+SELECT x + y FROM t_null
+```
+
+``` text
+┌─plus(x, y)─┐
+│       ᴺᵁᴸᴸ │
+│          5 │
+└────────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/data_types/nullable/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/simpleaggregatefunction.md b/docs/en/reference/sql-reference/data-types/simpleaggregatefunction.md
new file mode 100644
index 00000000000..1c04a71dedb
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/simpleaggregatefunction.md
@@ -0,0 +1,42 @@
+# SimpleAggregateFunction {#data-type-simpleaggregatefunction}
+
+`SimpleAggregateFunction(name, types_of_arguments…)` data type stores current value of the aggregate function, and does not store its full state as [`AggregateFunction`](../../sql-reference/data-types/aggregatefunction.md) does. This optimization can be applied to functions for which the following property holds: the result of applying a function `f` to a row set `S1 UNION ALL S2` can be obtained by applying `f` to parts of the row set separately, and then again applying `f` to the results: `f(S1 UNION ALL S2) = f(f(S1) UNION ALL f(S2))`. This property guarantees that partial aggregation results are enough to compute the combined one, so we do not have to store and process any extra data.
+
+The common way to produce an aggregate function value is by calling the aggregate function with the [-SimpleState](../../sql-reference/aggregate-functions/combinators.md#agg-functions-combinator-simplestate) suffix.
+
+The following aggregate functions are supported:
+
+-   [`any`](../../sql-reference/aggregate-functions/reference/any.md#agg_function-any)
+-   [`anyLast`](../../sql-reference/aggregate-functions/reference/anylast.md#anylastx)
+-   [`min`](../../sql-reference/aggregate-functions/reference/min.md#agg_function-min)
+-   [`max`](../../sql-reference/aggregate-functions/reference/max.md#agg_function-max)
+-   [`sum`](../../sql-reference/aggregate-functions/reference/sum.md#agg_function-sum)
+-   [`sumWithOverflow`](../../sql-reference/aggregate-functions/reference/sumwithoverflow.md#sumwithoverflowx)
+-   [`groupBitAnd`](../../sql-reference/aggregate-functions/reference/groupbitand.md#groupbitand)
+-   [`groupBitOr`](../../sql-reference/aggregate-functions/reference/groupbitor.md#groupbitor)
+-   [`groupBitXor`](../../sql-reference/aggregate-functions/reference/groupbitxor.md#groupbitxor)
+-   [`groupArrayArray`](../../sql-reference/aggregate-functions/reference/grouparray.md#agg_function-grouparray)
+-   [`groupUniqArrayArray`](../../sql-reference/aggregate-functions/reference/groupuniqarray.md)
+-   [`sumMap`](../../sql-reference/aggregate-functions/reference/summap.md#agg_functions-summap)
+-   [`minMap`](../../sql-reference/aggregate-functions/reference/minmap.md#agg_functions-minmap)
+-   [`maxMap`](../../sql-reference/aggregate-functions/reference/maxmap.md#agg_functions-maxmap)
+
+
+:::note    
+Values of the `SimpleAggregateFunction(func, Type)` look and stored the same way as `Type`, so you do not need to apply functions with `-Merge`/`-State` suffixes.
+
+`SimpleAggregateFunction` has better performance than `AggregateFunction` with same aggregation function.
+:::
+
+**Parameters**
+
+-   Name of the aggregate function.
+-   Types of the aggregate function arguments.
+
+**Example**
+
+``` sql
+CREATE TABLE simple (id UInt64, val SimpleAggregateFunction(sum, Double)) ENGINE=AggregatingMergeTree ORDER BY id;
+```
+
+[Original article](https://clickhouse.com/docs/en/data_types/simpleaggregatefunction/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/special-data-types/expression.md b/docs/en/reference/sql-reference/data-types/special-data-types/expression.md
new file mode 100644
index 00000000000..b6a2a2ebb9d
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/special-data-types/expression.md
@@ -0,0 +1,10 @@
+---
+sidebar_position: 58
+sidebar_label: Expression
+---
+
+# Expression {#expression}
+
+Expressions are used for representing lambdas in high-order functions.
+
+[Original article](https://clickhouse.com/docs/en/data_types/special_data_types/expression/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/special-data-types/index.md b/docs/en/reference/sql-reference/data-types/special-data-types/index.md
new file mode 100644
index 00000000000..5455d34a2a2
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/special-data-types/index.md
@@ -0,0 +1,10 @@
+---
+sidebar_label: Special Data Types
+sidebar_position: 55
+---
+
+# Special Data Types {#special-data-types}
+
+Special data type values can’t be serialized for saving in a table or output in query results, but can be used as an intermediate result during query execution.
+
+[Original article](https://clickhouse.com/docs/en/data_types/special_data_types/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/special-data-types/interval.md b/docs/en/reference/sql-reference/data-types/special-data-types/interval.md
new file mode 100644
index 00000000000..3ebeee01bf6
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/special-data-types/interval.md
@@ -0,0 +1,84 @@
+---
+sidebar_position: 61
+sidebar_label: Interval
+---
+
+# Interval {#data-type-interval}
+
+The family of data types representing time and date intervals. The resulting types of the [INTERVAL](../../../sql-reference/operators/index.md#operator-interval) operator.
+
+:::warning    
+`Interval` data type values can’t be stored in tables.
+:::
+
+Structure:
+
+-   Time interval as an unsigned integer value.
+-   Type of an interval.
+
+Supported interval types:
+
+-   `SECOND`
+-   `MINUTE`
+-   `HOUR`
+-   `DAY`
+-   `WEEK`
+-   `MONTH`
+-   `QUARTER`
+-   `YEAR`
+
+For each interval type, there is a separate data type. For example, the `DAY` interval corresponds to the `IntervalDay` data type:
+
+``` sql
+SELECT toTypeName(INTERVAL 4 DAY)
+```
+
+``` text
+┌─toTypeName(toIntervalDay(4))─┐
+│ IntervalDay                  │
+└──────────────────────────────┘
+```
+
+## Usage Remarks {#data-type-interval-usage-remarks}
+
+You can use `Interval`-type values in arithmetical operations with [Date](../../../sql-reference/data-types/date.md) and [DateTime](../../../sql-reference/data-types/datetime.md)-type values. For example, you can add 4 days to the current time:
+
+``` sql
+SELECT now() as current_date_time, current_date_time + INTERVAL 4 DAY
+```
+
+``` text
+┌───current_date_time─┬─plus(now(), toIntervalDay(4))─┐
+│ 2019-10-23 10:58:45 │           2019-10-27 10:58:45 │
+└─────────────────────┴───────────────────────────────┘
+```
+
+Intervals with different types can’t be combined. You can’t use intervals like `4 DAY 1 HOUR`. Specify intervals in units that are smaller or equal to the smallest unit of the interval, for example, the interval `1 day and an hour` interval can be expressed as `25 HOUR` or `90000 SECOND`.
+
+You can’t perform arithmetical operations with `Interval`-type values, but you can add intervals of different types consequently to values in `Date` or `DateTime` data types. For example:
+
+``` sql
+SELECT now() AS current_date_time, current_date_time + INTERVAL 4 DAY + INTERVAL 3 HOUR
+```
+
+``` text
+┌───current_date_time─┬─plus(plus(now(), toIntervalDay(4)), toIntervalHour(3))─┐
+│ 2019-10-23 11:16:28 │                                    2019-10-27 14:16:28 │
+└─────────────────────┴────────────────────────────────────────────────────────┘
+```
+
+The following query causes an exception:
+
+``` sql
+select now() AS current_date_time, current_date_time + (INTERVAL 4 DAY + INTERVAL 3 HOUR)
+```
+
+``` text
+Received exception from server (version 19.14.1):
+Code: 43. DB::Exception: Received from localhost:9000. DB::Exception: Wrong argument types for function plus: if one argument is Interval, then another must be Date or DateTime..
+```
+
+## See Also {#see-also}
+
+-   [INTERVAL](../../../sql-reference/operators/index.md#operator-interval) operator
+-   [toInterval](../../../sql-reference/functions/type-conversion-functions.md#function-tointerval) type conversion functions
diff --git a/docs/en/reference/sql-reference/data-types/special-data-types/nothing.md b/docs/en/reference/sql-reference/data-types/special-data-types/nothing.md
new file mode 100644
index 00000000000..f9f296f7dc4
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/special-data-types/nothing.md
@@ -0,0 +1,24 @@
+---
+sidebar_position: 60
+sidebar_label: Nothing
+---
+
+# Nothing {#nothing}
+
+The only purpose of this data type is to represent cases where a value is not expected. So you can’t create a `Nothing` type value.
+
+For example, literal [NULL](../../../sql-reference/syntax.md#null-literal) has type of `Nullable(Nothing)`. See more about [Nullable](../../../sql-reference/data-types/nullable.md).
+
+The `Nothing` type can also used to denote empty arrays:
+
+``` sql
+SELECT toTypeName(array())
+```
+
+``` text
+┌─toTypeName(array())─┐
+│ Array(Nothing)      │
+└─────────────────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/data_types/special_data_types/nothing/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/special-data-types/set.md b/docs/en/reference/sql-reference/data-types/special-data-types/set.md
new file mode 100644
index 00000000000..6d447b96f3b
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/special-data-types/set.md
@@ -0,0 +1,10 @@
+---
+sidebar_position: 59
+sidebar_label: Set
+---
+
+# Set {#set}
+
+Used for the right half of an [IN](../../../sql-reference/operators/in.md#select-in-operators) expression.
+
+[Original article](https://clickhouse.com/docs/en/data_types/special_data_types/set/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/string.md b/docs/en/reference/sql-reference/data-types/string.md
new file mode 100644
index 00000000000..e2903c7329d
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/string.md
@@ -0,0 +1,24 @@
+---
+sidebar_position: 44
+sidebar_label: String
+---
+
+# String {#string}
+
+Strings of an arbitrary length. The length is not limited. The value can contain an arbitrary set of bytes, including null bytes.
+The String type replaces the types VARCHAR, BLOB, CLOB, and others from other DBMSs.
+
+When creating tables, numeric parameters for string fields can be set (e.g. `VARCHAR(255)`), but ClickHouse ignores them.
+
+Aliases:
+
+-   `String` — `LONGTEXT`, `MEDIUMTEXT`, `TINYTEXT`, `TEXT`, `LONGBLOB`, `MEDIUMBLOB`, `TINYBLOB`, `BLOB`, `VARCHAR`, `CHAR`.
+
+## Encodings {#encodings}
+
+ClickHouse does not have the concept of encodings. Strings can contain an arbitrary set of bytes, which are stored and output as-is.
+If you need to store texts, we recommend using UTF-8 encoding. At the very least, if your terminal uses UTF-8 (as recommended), you can read and write your values without making conversions.
+Similarly, certain functions for working with strings have separate variations that work under the assumption that the string contains a set of bytes representing a UTF-8 encoded text.
+For example, the [length](../functions/string-functions.md#length) function calculates the string length in bytes, while the [lengthUTF8](../functions/string-functions.md#lengthutf8) function calculates the string length in Unicode code points, assuming that the value is UTF-8 encoded.
+
+[Original article](https://clickhouse.com/docs/en/data_types/string/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/tuple.md b/docs/en/reference/sql-reference/data-types/tuple.md
new file mode 100644
index 00000000000..eea48ab37b4
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/tuple.md
@@ -0,0 +1,78 @@
+---
+sidebar_position: 54
+sidebar_label: Tuple(T1, T2, ...)
+---
+
+# Tuple(t1, T2, …) {#tuplet1-t2}
+
+A tuple of elements, each having an individual [type](../../sql-reference/data-types/index.md#data_types).
+
+Tuples are used for temporary column grouping. Columns can be grouped when an IN expression is used in a query, and for specifying certain formal parameters of lambda functions. For more information, see the sections [IN operators](../../sql-reference/operators/in.md) and [Higher order functions](../../sql-reference/functions/index.md#higher-order-functions).
+
+Tuples can be the result of a query. In this case, for text formats other than JSON, values are comma-separated in brackets. In JSON formats, tuples are output as arrays (in square brackets).
+
+## Creating a Tuple {#creating-a-tuple}
+
+You can use a function to create a tuple:
+
+``` sql
+tuple(T1, T2, ...)
+```
+
+Example of creating a tuple:
+
+``` sql
+SELECT tuple(1,'a') AS x, toTypeName(x)
+```
+
+``` text
+┌─x───────┬─toTypeName(tuple(1, 'a'))─┐
+│ (1,'a') │ Tuple(UInt8, String)      │
+└─────────┴───────────────────────────┘
+```
+
+## Working with Data Types {#working-with-data-types}
+
+When creating a tuple on the fly, ClickHouse automatically detects the type of each argument as the minimum of the types which can store the argument value. If the argument is [NULL](../../sql-reference/syntax.md#null-literal), the type of the tuple element is [Nullable](../../sql-reference/data-types/nullable.md).
+
+Example of automatic data type detection:
+
+``` sql
+SELECT tuple(1, NULL) AS x, toTypeName(x)
+```
+
+``` text
+┌─x────────┬─toTypeName(tuple(1, NULL))──────┐
+│ (1,NULL) │ Tuple(UInt8, Nullable(Nothing)) │
+└──────────┴─────────────────────────────────┘
+```
+
+## Addressing Tuple Elements {#addressing-tuple-elements}
+
+It is possible to read elements of named tuples using indexes and names:
+
+``` sql
+CREATE TABLE named_tuples (`a` Tuple(s String, i Int64)) ENGINE = Memory;
+
+INSERT INTO named_tuples VALUES (('y', 10)), (('x',-10));
+
+SELECT a.s FROM named_tuples;
+
+SELECT a.2 FROM named_tuples;
+```
+
+Result:
+
+``` text
+┌─a.s─┐
+│ y   │
+│ x   │
+└─────┘
+
+┌─tupleElement(a, 2)─┐
+│                 10 │
+│                -10 │
+└────────────────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/data_types/tuple/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/data-types/uuid.md b/docs/en/reference/sql-reference/data-types/uuid.md
new file mode 100644
index 00000000000..010fc0b5cf5
--- /dev/null
+++ b/docs/en/reference/sql-reference/data-types/uuid.md
@@ -0,0 +1,75 @@
+---
+sidebar_position: 46
+sidebar_label: UUID
+---
+
+# UUID {#uuid-data-type}
+
+A universally unique identifier (UUID) is a 16-byte number used to identify records. For detailed information about the UUID, see [Wikipedia](https://en.wikipedia.org/wiki/Universally_unique_identifier).
+
+The example of UUID type value is represented below:
+
+``` text
+61f0c404-5cb3-11e7-907b-a6006ad3dba0
+```
+
+If you do not specify the UUID column value when inserting a new record, the UUID value is filled with zero:
+
+``` text
+00000000-0000-0000-0000-000000000000
+```
+
+## How to Generate {#how-to-generate}
+
+To generate the UUID value, ClickHouse provides the [generateUUIDv4](../../sql-reference/functions/uuid-functions.md) function.
+
+## Usage Example {#usage-example}
+
+**Example 1**
+
+This example demonstrates creating a table with the UUID type column and inserting a value into the table.
+
+``` sql
+CREATE TABLE t_uuid (x UUID, y String) ENGINE=TinyLog
+```
+
+``` sql
+INSERT INTO t_uuid SELECT generateUUIDv4(), 'Example 1'
+```
+
+``` sql
+SELECT * FROM t_uuid
+```
+
+``` text
+┌────────────────────────────────────x─┬─y─────────┐
+│ 417ddc5d-e556-4d27-95dd-a34d84e46a50 │ Example 1 │
+└──────────────────────────────────────┴───────────┘
+```
+
+**Example 2**
+
+In this example, the UUID column value is not specified when inserting a new record.
+
+``` sql
+INSERT INTO t_uuid (y) VALUES ('Example 2')
+```
+
+``` sql
+SELECT * FROM t_uuid
+```
+
+``` text
+┌────────────────────────────────────x─┬─y─────────┐
+│ 417ddc5d-e556-4d27-95dd-a34d84e46a50 │ Example 1 │
+│ 00000000-0000-0000-0000-000000000000 │ Example 2 │
+└──────────────────────────────────────┴───────────┘
+```
+
+## Restrictions {#restrictions}
+
+The UUID data type only supports functions which [String](../../sql-reference/data-types/string.md) data type also supports (for example, [min](../../sql-reference/aggregate-functions/reference/min.md#agg_function-min), [max](../../sql-reference/aggregate-functions/reference/max.md#agg_function-max), and [count](../../sql-reference/aggregate-functions/reference/count.md#agg_function-count)).
+
+The UUID data type is not supported by arithmetic operations (for example, [abs](../../sql-reference/functions/arithmetic-functions.md#arithm_func-abs)) or aggregate functions, such as [sum](../../sql-reference/aggregate-functions/reference/sum.md#agg_function-sum) and [avg](../../sql-reference/aggregate-functions/reference/avg.md#agg_function-avg).
+
+[Original article](https://clickhouse.com/docs/en/data_types/uuid/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/dictionaries/external-dictionaries/_category_.yml b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/_category_.yml
new file mode 100644
index 00000000000..02468f87a82
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/_category_.yml
@@ -0,0 +1,8 @@
+position: 37
+label: 'External Dictionaries'
+collapsible: true
+collapsed: true
+link:
+  type: generated-index
+  title: External Dictionaries
+  slug: /en/sql-reference/dictionaries/external-dictionaries
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-hierarchical.md b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-hierarchical.md
new file mode 100644
index 00000000000..6df7cf231b9
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-hierarchical.md
@@ -0,0 +1,67 @@
+---
+sidebar_position: 45
+sidebar_label: Hierarchical dictionaries
+---
+
+# Hierarchical Dictionaries 
+
+ClickHouse supports hierarchical dictionaries with a [numeric key](../../dictionaries/external-dictionaries/external-dicts-dict-structure.md#numeric-key).
+
+Look at the following hierarchical structure:
+
+``` text
+0 (Common parent)
+│
+├── 1 (Russia)
+│   │
+│   └── 2 (Moscow)
+│       │
+│       └── 3 (Center)
+│
+└── 4 (Great Britain)
+    │
+    └── 5 (London)
+```
+
+This hierarchy can be expressed as the following dictionary table.
+
+| region_id | parent_region | region_name  |
+|------------|----------------|---------------|
+| 1          | 0              | Russia        |
+| 2          | 1              | Moscow        |
+| 3          | 2              | Center        |
+| 4          | 0              | Great Britain |
+| 5          | 4              | London        |
+
+This table contains a column `parent_region` that contains the key of the nearest parent for the element.
+
+ClickHouse supports the [hierarchical](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#hierarchical-dict-attr) property for [external dictionary](../../../sql-reference/dictionaries/external-dictionaries/) attributes. This property allows you to configure the hierarchical dictionary similar to described above.
+
+The [dictGetHierarchy](../../../sql-reference/functions/ext-dict-functions.md#dictgethierarchy) function allows you to get the parent chain of an element.
+
+For our example, the structure of dictionary can be the following:
+
+``` xml
+<dictionary>
+    <structure>
+        <id>
+            <name>region_id</name>
+        </id>
+
+        <attribute>
+            <name>parent_region</name>
+            <type>UInt64</type>
+            <null_value>0</null_value>
+            <hierarchical>true</hierarchical>
+        </attribute>
+
+        <attribute>
+            <name>region_name</name>
+            <type>String</type>
+            <null_value></null_value>
+        </attribute>
+
+    </structure>
+</dictionary>
+```
+
diff --git a/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md
new file mode 100644
index 00000000000..bd88a8b09f7
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md
@@ -0,0 +1,557 @@
+---
+sidebar_position: 41
+sidebar_label: Storing Dictionaries in Memory
+---
+
+# Storing Dictionaries in Memory 
+
+There are a variety of ways to store dictionaries in memory.
+
+We recommend [flat](#flat), [hashed](#dicts-external_dicts_dict_layout-hashed) and [complex_key_hashed](#complex-key-hashed), which provide optimal processing speed.
+
+Caching is not recommended because of potentially poor performance and difficulties in selecting optimal parameters. Read more in the section [cache](#cache).
+
+There are several ways to improve dictionary performance:
+
+-   Call the function for working with the dictionary after `GROUP BY`.
+-   Mark attributes to extract as injective. An attribute is called injective if different attribute values correspond to different keys. So when `GROUP BY` uses a function that fetches an attribute value by the key, this function is automatically taken out of `GROUP BY`.
+
+ClickHouse generates an exception for errors with dictionaries. Examples of errors:
+
+-   The dictionary being accessed could not be loaded.
+-   Error querying a `cached` dictionary.
+
+You can view the list of external dictionaries and their statuses in the `system.dictionaries` table.
+
+The configuration looks like this:
+
+``` xml
+<clickhouse>
+    <dictionary>
+        ...
+        <layout>
+            <layout_type>
+                <!-- layout settings -->
+            </layout_type>
+        </layout>
+        ...
+    </dictionary>
+</clickhouse>
+```
+
+Corresponding [DDL-query](../../../sql-reference/statements/create/dictionary.md):
+
+``` sql
+CREATE DICTIONARY (...)
+...
+LAYOUT(LAYOUT_TYPE(param value)) -- layout settings
+...
+```
+
+## Ways to Store Dictionaries in Memory {#ways-to-store-dictionaries-in-memory}
+
+-   [flat](#flat)
+-   [hashed](#dicts-external_dicts_dict_layout-hashed)
+-   [sparse_hashed](#dicts-external_dicts_dict_layout-sparse_hashed)
+-   [complex_key_hashed](#complex-key-hashed)
+-   [complex_key_sparse_hashed](#complex-key-sparse-hashed)
+-   [hashed_array](#dicts-external_dicts_dict_layout-hashed-array)
+-   [complex_key_hashed_array](#complex-key-hashed-array)
+-   [range_hashed](#range-hashed)
+-   [complex_key_range_hashed](#complex-key-range-hashed)
+-   [cache](#cache)
+-   [complex_key_cache](#complex-key-cache)
+-   [ssd_cache](#ssd-cache)
+-   [complex_key_ssd_cache](#complex-key-ssd-cache)
+-   [direct](#direct)
+-   [complex_key_direct](#complex-key-direct)
+-   [ip_trie](#ip-trie)
+
+### flat {#flat}
+
+The dictionary is completely stored in memory in the form of flat arrays. How much memory does the dictionary use? The amount is proportional to the size of the largest key (in space used).
+
+The dictionary key has the [UInt64](../../../sql-reference/data-types/int-uint.md) type and the value is limited to `max_array_size` (by default — 500,000). If a larger key is discovered when creating the dictionary, ClickHouse throws an exception and does not create the dictionary. Dictionary flat arrays initial size is controlled by `initial_array_size` setting (by default — 1024).
+
+All types of sources are supported. When updating, data (from a file or from a table) is read in it entirety.
+
+This method provides the best performance among all available methods of storing the dictionary.
+
+Configuration example:
+
+``` xml
+<layout>
+  <flat>
+    <initial_array_size>50000</initial_array_size>
+    <max_array_size>5000000</max_array_size>
+  </flat>
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(FLAT(INITIAL_ARRAY_SIZE 50000 MAX_ARRAY_SIZE 5000000))
+```
+
+### hashed {#dicts-external_dicts_dict_layout-hashed}
+
+The dictionary is completely stored in memory in the form of a hash table. The dictionary can contain any number of elements with any identifiers In practice, the number of keys can reach tens of millions of items.
+
+If `preallocate` is `true` (default is `false`) the hash table will be preallocated (this will make the dictionary load faster). But note that you should use it only if:
+
+- The source support an approximate number of elements (for now it is supported only by the `ClickHouse` source).
+- There are no duplicates in the data (otherwise it may increase memory usage for the hashtable).
+
+All types of sources are supported. When updating, data (from a file or from a table) is read in its entirety.
+
+Configuration example:
+
+``` xml
+<layout>
+  <hashed>
+    <preallocate>0</preallocate>
+  </hashed>
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(HASHED(PREALLOCATE 0))
+```
+
+### sparse_hashed {#dicts-external_dicts_dict_layout-sparse_hashed}
+
+Similar to `hashed`, but uses less memory in favor more CPU usage.
+
+It will be also preallocated so as `hashed` (with `preallocate` set to `true`), and note that it is even more significant for `sparse_hashed`.
+
+Configuration example:
+
+``` xml
+<layout>
+  <sparse_hashed />
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(SPARSE_HASHED([PREALLOCATE 0]))
+```
+
+### complex_key_hashed {#complex-key-hashed}
+
+This type of storage is for use with composite [keys](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md). Similar to `hashed`.
+
+Configuration example:
+
+``` xml
+<layout>
+  <complex_key_hashed />
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(COMPLEX_KEY_HASHED())
+```
+
+### complex_key_sparse_hashed {#complex-key-sparse-hashed}
+
+This type of storage is for use with composite [keys](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md). Similar to [sparse_hashed](#dicts-external_dicts_dict_layout-sparse_hashed).
+
+Configuration example:
+
+``` xml
+<layout>
+  <complex_key_sparse_hashed />
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(COMPLEX_KEY_SPARSE_HASHED())
+```
+
+### hashed_array {#dicts-external_dicts_dict_layout-hashed-array}
+
+The dictionary is completely stored in memory. Each attribute is stored in an array. The key attribute is stored in the form of a hashed table where value is an index in the attributes array. The dictionary can contain any number of elements with any identifiers. In practice, the number of keys can reach tens of millions of items.
+
+All types of sources are supported. When updating, data (from a file or from a table) is read in its entirety.
+
+Configuration example:
+
+``` xml
+<layout>
+  <hashed_array>
+  </hashed_array>
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(HASHED_ARRAY())
+```
+
+### complex_key_hashed_array {#complex-key-hashed-array}
+
+This type of storage is for use with composite [keys](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md). Similar to [hashed_array](#dicts-external_dicts_dict_layout-hashed-array).
+
+Configuration example:
+
+``` xml
+<layout>
+  <complex_key_hashed_array />
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(COMPLEX_KEY_HASHED_ARRAY())
+```
+
+### range_hashed {#range-hashed}
+
+The dictionary is stored in memory in the form of a hash table with an ordered array of ranges and their corresponding values.
+
+This storage method works the same way as hashed and allows using date/time (arbitrary numeric type) ranges in addition to the key.
+
+Example: The table contains discounts for each advertiser in the format:
+
+``` text
++---------|-------------|-------------|------+
+| advertiser id | discount start date | discount end date | amount |
++===============+=====================+===================+========+
+| 123           | 2015-01-01          | 2015-01-15        | 0.15   |
++---------|-------------|-------------|------+
+| 123           | 2015-01-16          | 2015-01-31        | 0.25   |
++---------|-------------|-------------|------+
+| 456           | 2015-01-01          | 2015-01-15        | 0.05   |
++---------|-------------|-------------|------+
+```
+
+To use a sample for date ranges, define the `range_min` and `range_max` elements in the [structure](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md). These elements must contain elements `name` and `type` (if `type` is not specified, the default type will be used - Date). `type` can be any numeric type (Date / DateTime / UInt64 / Int32 / others).
+
+:::warning    
+Values of `range_min` and `range_max` should fit in `Int64` type.
+:::
+
+Example:
+
+``` xml
+<structure>
+    <id>
+        <name>Id</name>
+    </id>
+    <range_min>
+        <name>first</name>
+        <type>Date</type>
+    </range_min>
+    <range_max>
+        <name>last</name>
+        <type>Date</type>
+    </range_max>
+    ...
+```
+
+or
+
+``` sql
+CREATE DICTIONARY somedict (
+    id UInt64,
+    first Date,
+    last Date
+)
+PRIMARY KEY id
+LAYOUT(RANGE_HASHED())
+RANGE(MIN first MAX last)
+```
+
+To work with these dictionaries, you need to pass an additional argument to the `dictGetT` function, for which a range is selected:
+
+``` sql
+dictGetT('dict_name', 'attr_name', id, date)
+```
+
+This function returns the value for the specified `id`s and the date range that includes the passed date.
+
+Details of the algorithm:
+
+-   If the `id` is not found or a range is not found for the `id`, it returns the default value for the dictionary.
+-   If there are overlapping ranges, it returns value for any (random) range.
+-   If the range delimiter is `NULL` or an invalid date (such as 1900-01-01), the range is open. The range can be open on both sides.
+
+Configuration example:
+
+``` xml
+<clickhouse>
+    <dictionary>
+        ...
+
+        <layout>
+            <range_hashed />
+        </layout>
+
+        <structure>
+            <id>
+                <name>Abcdef</name>
+            </id>
+            <range_min>
+                <name>StartTimeStamp</name>
+                <type>UInt64</type>
+            </range_min>
+            <range_max>
+                <name>EndTimeStamp</name>
+                <type>UInt64</type>
+            </range_max>
+            <attribute>
+                <name>XXXType</name>
+                <type>String</type>
+                <null_value />
+            </attribute>
+        </structure>
+
+    </dictionary>
+</clickhouse>
+```
+
+or
+
+``` sql
+CREATE DICTIONARY somedict(
+    Abcdef UInt64,
+    StartTimeStamp UInt64,
+    EndTimeStamp UInt64,
+    XXXType String DEFAULT ''
+)
+PRIMARY KEY Abcdef
+RANGE(MIN StartTimeStamp MAX EndTimeStamp)
+```
+
+### complex_key_range_hashed {#complex-key-range-hashed}
+
+The dictionary is stored in memory in the form of a hash table with an ordered array of ranges and their corresponding values (see [range_hashed](#range-hashed)). This type of storage is for use with composite [keys](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md).
+
+Configuration example:
+
+``` sql
+CREATE DICTIONARY range_dictionary
+(
+  CountryID UInt64,
+  CountryKey String,
+  StartDate Date,
+  EndDate Date,
+  Tax Float64 DEFAULT 0.2
+)
+PRIMARY KEY CountryID, CountryKey
+SOURCE(CLICKHOUSE(TABLE 'date_table'))
+LIFETIME(MIN 1 MAX 1000)
+LAYOUT(COMPLEX_KEY_RANGE_HASHED())
+RANGE(MIN StartDate MAX EndDate);
+```
+
+### cache {#cache}
+
+The dictionary is stored in a cache that has a fixed number of cells. These cells contain frequently used elements.
+
+When searching for a dictionary, the cache is searched first. For each block of data, all keys that are not found in the cache or are outdated are requested from the source using `SELECT attrs... FROM db.table WHERE id IN (k1, k2, ...)`. The received data is then written to the cache.
+
+If keys are not found in dictionary, then update cache task is created and added into update queue. Update queue properties can be controlled with settings `max_update_queue_size`, `update_queue_push_timeout_milliseconds`, `query_wait_timeout_milliseconds`, `max_threads_for_updates`.
+
+For cache dictionaries, the expiration [lifetime](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md) of data in the cache can be set. If more time than `lifetime` has passed since loading the data in a cell, the cell’s value is not used and key becomes expired. The key is re-requested the next time it needs to be used. This behaviour can be configured with setting `allow_read_expired_keys`.
+
+This is the least effective of all the ways to store dictionaries. The speed of the cache depends strongly on correct settings and the usage scenario. A cache type dictionary performs well only when the hit rates are high enough (recommended 99% and higher). You can view the average hit rate in the [system.dictionaries](../../../operations/system-tables/dictionaries.md) table.
+
+If setting `allow_read_expired_keys` is set to 1, by default 0. Then dictionary can support asynchronous updates. If a client requests keys and all of them are in cache, but some of them are expired, then dictionary will return expired keys for a client and request them asynchronously from the source.
+
+To improve cache performance, use a subquery with `LIMIT`, and call the function with the dictionary externally.
+
+Supported [sources](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md): MySQL, ClickHouse, executable, HTTP.
+
+Example of settings:
+
+``` xml
+<layout>
+    <cache>
+        <!-- The size of the cache, in number of cells. Rounded up to a power of two. -->
+        <size_in_cells>1000000000</size_in_cells>
+        <!-- Allows to read expired keys. -->
+        <allow_read_expired_keys>0</allow_read_expired_keys>
+        <!-- Max size of update queue. -->
+        <max_update_queue_size>100000</max_update_queue_size>
+        <!-- Max timeout in milliseconds for push update task into queue. -->
+        <update_queue_push_timeout_milliseconds>10</update_queue_push_timeout_milliseconds>
+        <!-- Max wait timeout in milliseconds for update task to complete. -->
+        <query_wait_timeout_milliseconds>60000</query_wait_timeout_milliseconds>
+        <!-- Max threads for cache dictionary update. -->
+        <max_threads_for_updates>4</max_threads_for_updates>
+    </cache>
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(CACHE(SIZE_IN_CELLS 1000000000))
+```
+
+Set a large enough cache size. You need to experiment to select the number of cells:
+
+1.  Set some value.
+2.  Run queries until the cache is completely full.
+3.  Assess memory consumption using the `system.dictionaries` table.
+4.  Increase or decrease the number of cells until the required memory consumption is reached.
+
+:::warning    
+Do not use ClickHouse as a source, because it is slow to process queries with random reads.
+:::
+
+### complex_key_cache {#complex-key-cache}
+
+This type of storage is for use with composite [keys](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md). Similar to `cache`.
+
+### ssd_cache {#ssd-cache}
+
+Similar to `cache`, but stores data on SSD and index in RAM. All cache dictionary settings related to update queue can also be applied to SSD cache dictionaries.
+
+``` xml
+<layout>
+    <ssd_cache>
+        <!-- Size of elementary read block in bytes. Recommended to be equal to SSD's page size. -->
+        <block_size>4096</block_size>
+        <!-- Max cache file size in bytes. -->
+        <file_size>16777216</file_size>
+        <!-- Size of RAM buffer in bytes for reading elements from SSD. -->
+        <read_buffer_size>131072</read_buffer_size>
+        <!-- Size of RAM buffer in bytes for aggregating elements before flushing to SSD. -->
+        <write_buffer_size>1048576</write_buffer_size>
+        <!-- Path where cache file will be stored. -->
+        <path>/var/lib/clickhouse/user_files/test_dict</path>
+    </ssd_cache>
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(SSD_CACHE(BLOCK_SIZE 4096 FILE_SIZE 16777216 READ_BUFFER_SIZE 1048576
+    PATH '/var/lib/clickhouse/user_files/test_dict'))
+```
+
+### complex_key_ssd_cache {#complex-key-ssd-cache}
+
+This type of storage is for use with composite [keys](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md). Similar to `ssd_cache`.
+
+### direct {#direct}
+
+The dictionary is not stored in memory and directly goes to the source during the processing of a request.
+
+The dictionary key has the `UInt64` type.
+
+All types of [sources](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md), except local files, are supported.
+
+Configuration example:
+
+``` xml
+<layout>
+  <direct />
+</layout>
+```
+
+or
+
+``` sql
+LAYOUT(DIRECT())
+```
+
+### complex_key_direct {#complex-key-direct}
+
+This type of storage is for use with composite [keys](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md). Similar to `direct`.
+
+### ip_trie {#ip-trie}
+
+This type of storage is for mapping network prefixes (IP addresses) to metadata such as ASN.
+
+Example: The table contains network prefixes and their corresponding AS number and country code:
+
+``` text
+  +-----------|-----|------+
+  | prefix          | asn   | cca2   |
+  +=================+=======+========+
+  | 202.79.32.0/20  | 17501 | NP     |
+  +-----------|-----|------+
+  | 2620:0:870::/48 | 3856  | US     |
+  +-----------|-----|------+
+  | 2a02:6b8:1::/48 | 13238 | RU     |
+  +-----------|-----|------+
+  | 2001:db8::/32   | 65536 | ZZ     |
+  +-----------|-----|------+
+```
+
+When using this type of layout, the structure must have a composite key.
+
+Example:
+
+``` xml
+<structure>
+    <key>
+        <attribute>
+            <name>prefix</name>
+            <type>String</type>
+        </attribute>
+    </key>
+    <attribute>
+            <name>asn</name>
+            <type>UInt32</type>
+            <null_value />
+    </attribute>
+    <attribute>
+            <name>cca2</name>
+            <type>String</type>
+            <null_value>??</null_value>
+    </attribute>
+    ...
+</structure>
+<layout>
+    <ip_trie>
+        <!-- Key attribute `prefix` can be retrieved via dictGetString. -->
+        <!-- This option increases memory usage. -->
+        <access_to_key_from_attributes>true</access_to_key_from_attributes>
+    </ip_trie>
+</layout>
+```
+
+or
+
+``` sql
+CREATE DICTIONARY somedict (
+    prefix String,
+    asn UInt32,
+    cca2 String DEFAULT '??'
+)
+PRIMARY KEY prefix
+```
+
+The key must have only one String type attribute that contains an allowed IP prefix. Other types are not supported yet.
+
+For queries, you must use the same functions (`dictGetT` with a tuple) as for dictionaries with composite keys:
+
+``` sql
+dictGetT('dict_name', 'attr_name', tuple(ip))
+```
+
+The function takes either `UInt32` for IPv4, or `FixedString(16)` for IPv6:
+
+``` sql
+dictGetString('prefix', 'asn', tuple(IPv6StringToNum('2001:db8::1')))
+```
+
+Other types are not supported yet. The function returns the attribute for the prefix that corresponds to this IP address. If there are overlapping prefixes, the most specific one is returned.
+
+Data must completely fit into RAM.
diff --git a/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md
new file mode 100644
index 00000000000..ab83017f263
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md
@@ -0,0 +1,119 @@
+---
+sidebar_position: 42
+sidebar_label: Dictionary Updates
+---
+
+# Dictionary Updates 
+
+ClickHouse periodically updates the dictionaries. The update interval for fully downloaded dictionaries and the invalidation interval for cached dictionaries are defined in the `lifetime` tag in seconds.
+
+Dictionary updates (other than loading for first use) do not block queries. During updates, the old version of a dictionary is used. If an error occurs during an update, the error is written to the server log, and queries continue using the old version of dictionaries.
+
+Example of settings:
+
+``` xml
+<dictionary>
+    ...
+    <lifetime>300</lifetime>
+    ...
+</dictionary>
+```
+
+or
+
+``` sql
+CREATE DICTIONARY (...)
+...
+LIFETIME(300)
+...
+```
+
+Setting `<lifetime>0</lifetime>` (`LIFETIME(0)`) prevents dictionaries from updating.
+
+You can set a time interval for updates, and ClickHouse will choose a uniformly random time within this range. This is necessary in order to distribute the load on the dictionary source when updating on a large number of servers.
+
+Example of settings:
+
+``` xml
+<dictionary>
+    ...
+    <lifetime>
+        <min>300</min>
+        <max>360</max>
+    </lifetime>
+    ...
+</dictionary>
+```
+
+or
+
+``` sql
+LIFETIME(MIN 300 MAX 360)
+```
+
+If `<min>0</min>` and `<max>0</max>`, ClickHouse does not reload the dictionary by timeout.
+In this case, ClickHouse can reload the dictionary earlier if the dictionary configuration file was changed or the `SYSTEM RELOAD DICTIONARY` command was executed.
+
+When updating the dictionaries, the ClickHouse server applies different logic depending on the type of [source](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md):
+
+-   For a text file, it checks the time of modification. If the time differs from the previously recorded time, the dictionary is updated.
+-   For MySQL source, the time of modification is checked using a `SHOW TABLE STATUS` query (in case of MySQL 8 you need to disable meta-information caching in MySQL by `set global information_schema_stats_expiry=0`).
+-   Dictionaries from other sources are updated every time by default.
+
+For other sources (ODBC, PostgreSQL, ClickHouse, etc), you can set up a query that will update the dictionaries only if they really changed, rather than each time. To do this, follow these steps:
+
+-   The dictionary table must have a field that always changes when the source data is updated.
+-   The settings of the source must specify a query that retrieves the changing field. The ClickHouse server interprets the query result as a row, and if this row has changed relative to its previous state, the dictionary is updated. Specify the query in the `<invalidate_query>` field in the settings for the [source](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md).
+
+Example of settings:
+
+``` xml
+<dictionary>
+    ...
+    <odbc>
+      ...
+      <invalidate_query>SELECT update_time FROM dictionary_source where id = 1</invalidate_query>
+    </odbc>
+    ...
+</dictionary>
+```
+
+or
+
+``` sql
+...
+SOURCE(ODBC(... invalidate_query 'SELECT update_time FROM dictionary_source where id = 1'))
+...
+```
+
+For `Cache`, `ComplexKeyCache`, `SSDCache`, and `SSDComplexKeyCache` dictionaries both synchronious and asynchronious updates are supported.
+
+It is also possible for `Flat`, `Hashed`, `ComplexKeyHashed` dictionaries to only request data that was changed after the previous update. If `update_field` is specified as part of the dictionary source configuration, value of the previous update time in seconds will be added to the data request. Depends on source type (Executable, HTTP, MySQL, PostgreSQL, ClickHouse, or ODBC) different logic will be applied to `update_field` before request data from an external source.
+
+-   If the source is HTTP then `update_field` will be added as a query parameter with the last update time as the parameter value.
+-   If the source is Executable then `update_field` will be added as an executable script argument with the last update time as the argument value.
+-   If the source is ClickHouse, MySQL, PostgreSQL, ODBC there will be an additional part of `WHERE`, where `update_field` is compared as greater or equal with the last update time.
+
+If `update_field` option is set, additional option `update_lag` can be set. Value of `update_lag` option is subtracted from previous update time before request updated data.
+
+Example of settings:
+
+``` xml
+<dictionary>
+    ...
+        <clickhouse>
+            ...
+            <update_field>added_time</update_field>
+            <update_lag>15</update_lag>
+        </clickhouse>
+    ...
+</dictionary>
+```
+
+or
+
+``` sql
+...
+SOURCE(CLICKHOUSE(... update_field 'added_time' update_lag 15))
+...
+```
diff --git a/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-polygon.md b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-polygon.md
new file mode 100644
index 00000000000..7fcea84b55d
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-polygon.md
@@ -0,0 +1,131 @@
+---
+sidebar_position: 46
+sidebar_label: Polygon Dictionaries With Grids
+---
+
+# Polygon dictionaries 
+
+Polygon dictionaries allow you to efficiently search for the polygon containing specified points.
+For example: defining a city area by geographical coordinates.
+
+Example of a polygon dictionary configuration:
+
+``` xml
+<dictionary>
+    <structure>
+        <key>
+            <name>key</name>
+            <type>Array(Array(Array(Array(Float64))))</type>
+        </key>
+
+        <attribute>
+            <name>name</name>
+            <type>String</type>
+            <null_value></null_value>
+        </attribute>
+
+        <attribute>
+            <name>value</name>
+            <type>UInt64</type>
+            <null_value>0</null_value>
+        </attribute>
+    </structure>
+
+    <layout>
+        <polygon>
+            <store_polygon_key_column>1</store_polygon_key_column>
+        </polygon>
+    </layout>
+
+    ...
+</dictionary>
+```
+
+The corresponding [DDL-query](../../../sql-reference/statements/create/dictionary.md#create-dictionary-query):
+``` sql
+CREATE DICTIONARY polygon_dict_name (
+    key Array(Array(Array(Array(Float64)))),
+    name String,
+    value UInt64
+)
+PRIMARY KEY key
+LAYOUT(POLYGON(STORE_POLYGON_KEY_COLUMN 1))
+...
+```
+
+When configuring the polygon dictionary, the key must have one of two types:
+
+-   A simple polygon. It is an array of points.
+-   MultiPolygon. It is an array of polygons. Each polygon is a two-dimensional array of points. The first element of this array is the outer boundary of the polygon, and subsequent elements specify areas to be excluded from it.
+
+Points can be specified as an array or a tuple of their coordinates. In the current implementation, only two-dimensional points are supported.
+
+The user can [upload their own data](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md) in all formats supported by ClickHouse.
+
+There are 3 types of [in-memory storage](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md) available:
+
+-   `POLYGON_SIMPLE`. This is a naive implementation, where a linear pass through all polygons is made for each query, and membership is checked for each one without using additional indexes.
+
+-   `POLYGON_INDEX_EACH`. A separate index is built for each polygon, which allows you to quickly check whether it belongs in most cases (optimized for geographical regions).
+Also, a grid is superimposed on the area under consideration, which significantly narrows the number of polygons under consideration.
+The grid is created by recursively dividing the cell into 16 equal parts and is configured with two parameters.
+The division stops when the recursion depth reaches `MAX_DEPTH` or when the cell crosses no more than `MIN_INTERSECTIONS` polygons.
+To respond to the query, there is a corresponding cell, and the index for the polygons stored in it is accessed alternately.
+
+-   `POLYGON_INDEX_CELL`. This placement also creates the grid described above. The same options are available. For each sheet cell, an index is built on all pieces of polygons that fall into it, which allows you to quickly respond to a request.
+
+-   `POLYGON`. Synonym to `POLYGON_INDEX_CELL`.
+
+Dictionary queries are carried out using standard [functions](../../../sql-reference/functions/ext-dict-functions.md) for working with external dictionaries.
+An important difference is that here the keys will be the points for which you want to find the polygon containing them.
+
+**Example**
+
+Example of working with the dictionary defined above:
+
+``` sql
+CREATE TABLE points (
+    x Float64,
+    y Float64
+)
+...
+SELECT tuple(x, y) AS key, dictGet(dict_name, 'name', key), dictGet(dict_name, 'value', key) FROM points ORDER BY x, y;
+```
+
+As a result of executing the last command for each point in the 'points' table, a minimum area polygon containing this point will be found, and the requested attributes will be output.
+
+**Example**
+
+You can read columns from polygon dictionaries via SELECT query, just turn on the `store_polygon_key_column = 1` in the dictionary configuration or corresponding DDL-query.
+
+Query:
+
+``` sql
+CREATE TABLE polygons_test_table
+(
+    key Array(Array(Array(Tuple(Float64, Float64)))),
+    name String
+) ENGINE = TinyLog;
+
+INSERT INTO polygons_test_table VALUES ([[[(3, 1), (0, 1), (0, -1), (3, -1)]]], 'Value');
+
+CREATE DICTIONARY polygons_test_dictionary
+(
+    key Array(Array(Array(Tuple(Float64, Float64)))),
+    name String
+)
+PRIMARY KEY key
+SOURCE(CLICKHOUSE(TABLE 'polygons_test_table'))
+LAYOUT(POLYGON(STORE_POLYGON_KEY_COLUMN 1))
+LIFETIME(0);
+
+SELECT * FROM polygons_test_dictionary;
+```
+
+Result:
+
+``` text
+┌─key─────────────────────────────┬─name──┐
+│ [[[(3,1),(0,1),(0,-1),(3,-1)]]] │ Value │
+└─────────────────────────────────┴───────┘
+```
diff --git a/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md
new file mode 100644
index 00000000000..443f72ad72b
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md
@@ -0,0 +1,818 @@
+---
+sidebar_position: 43
+sidebar_label: Sources of External Dictionaries
+---
+
+# Sources of External Dictionaries 
+
+An external dictionary can be connected from many different sources.
+
+If dictionary is configured using xml-file, the configuration looks like this:
+
+``` xml
+<clickhouse>
+  <dictionary>
+    ...
+    <source>
+      <source_type>
+        <!-- Source configuration -->
+      </source_type>
+    </source>
+    ...
+  </dictionary>
+  ...
+</clickhouse>
+```
+
+In case of [DDL-query](../../../sql-reference/statements/create/dictionary.md), equal configuration will looks like:
+
+``` sql
+CREATE DICTIONARY dict_name (...)
+...
+SOURCE(SOURCE_TYPE(param1 val1 ... paramN valN)) -- Source configuration
+...
+```
+
+The source is configured in the `source` section.
+
+For source types [Local file](#dicts-external_dicts_dict_sources-local_file), [Executable file](#dicts-external_dicts_dict_sources-executable), [HTTP(s)](#dicts-external_dicts_dict_sources-http), [ClickHouse](#dicts-external_dicts_dict_sources-clickhouse)
+optional settings are available:
+
+``` xml
+<source>
+  <file>
+    <path>/opt/dictionaries/os.tsv</path>
+    <format>TabSeparated</format>
+  </file>
+  <settings>
+      <format_csv_allow_single_quotes>0</format_csv_allow_single_quotes>
+  </settings>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(FILE(path './user_files/os.tsv' format 'TabSeparated'))
+SETTINGS(format_csv_allow_single_quotes = 0)
+```
+
+Types of sources (`source_type`):
+
+-   [Local file](#dicts-external_dicts_dict_sources-local_file)
+-   [Executable File](#dicts-external_dicts_dict_sources-executable)
+-   [Executable Pool](#dicts-external_dicts_dict_sources-executable_pool)
+-   [HTTP(s)](#dicts-external_dicts_dict_sources-http)
+-   DBMS
+    -   [ODBC](#dicts-external_dicts_dict_sources-odbc)
+    -   [MySQL](#dicts-external_dicts_dict_sources-mysql)
+    -   [ClickHouse](#dicts-external_dicts_dict_sources-clickhouse)
+    -   [MongoDB](#dicts-external_dicts_dict_sources-mongodb)
+    -   [Redis](#dicts-external_dicts_dict_sources-redis)
+    -   [Cassandra](#dicts-external_dicts_dict_sources-cassandra)
+    -   [PostgreSQL](#dicts-external_dicts_dict_sources-postgresql)
+
+## Local File {#dicts-external_dicts_dict_sources-local_file}
+
+Example of settings:
+
+``` xml
+<source>
+  <file>
+    <path>/opt/dictionaries/os.tsv</path>
+    <format>TabSeparated</format>
+  </file>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(FILE(path './user_files/os.tsv' format 'TabSeparated'))
+```
+
+Setting fields:
+
+-   `path` – The absolute path to the file.
+-   `format` – The file format. All the formats described in [Formats](../../../interfaces/formats.md#formats) are supported.
+
+When dictionary with source `FILE` is created via DDL command (`CREATE DICTIONARY ...`), the source file needs to be located in `user_files` directory, to prevent DB users accessing arbitrary file on ClickHouse node.
+
+**See Also**
+
+-   [Dictionary function](../../../sql-reference/table-functions/dictionary.md#dictionary-function)
+
+## Executable File {#dicts-external_dicts_dict_sources-executable}
+
+Working with executable files depends on [how the dictionary is stored in memory](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md). If the dictionary is stored using `cache` and `complex_key_cache`, ClickHouse requests the necessary keys by sending a request to the executable file’s STDIN. Otherwise, ClickHouse starts executable file and treats its output as dictionary data.
+
+Example of settings:
+
+``` xml
+<source>
+    <executable>
+        <command>cat /opt/dictionaries/os.tsv</command>
+        <format>TabSeparated</format>
+        <implicit_key>false</implicit_key>
+    </executable>
+</source>
+```
+
+Setting fields:
+
+-   `command` — The absolute path to the executable file, or the file name (if the program directory is written to `PATH`).
+-   `format` — The file format. All the formats described in [Formats](../../../interfaces/formats.md#formats) are supported.
+-   `command_termination_timeout` — executable script should contain main read-write loop. After dictionary is destroyed, pipe is closed, and executable file will have `command_termination_timeout` seconds to shutdown, before ClickHouse will send SIGTERM signal to child process. Specified in seconds. Default value is 10. Optional parameter.
+-   `command_read_timeout` - timeout for reading data from command stdout in milliseconds. Default value 10000. Optional parameter.
+-   `command_write_timeout` - timeout for writing data to command stdin in milliseconds. Default value 10000. Optional parameter.
+-   `implicit_key` — The executable source file can return only values, and the correspondence to the requested keys is determined implicitly — by the order of rows in the result. Default value is false.
+-   `execute_direct` - If `execute_direct` = `1`, then `command` will be searched inside user_scripts folder. Additional script arguments can be specified using whitespace separator. Example: `script_name arg1 arg2`. If `execute_direct` = `0`, `command` is passed as argument for `bin/sh -c`. Default value is `0`. Optional parameter.
+-   `send_chunk_header` - controls whether to send row count before sending a chunk of data to process. Optional. Default value is `false`.
+
+That dictionary source can be configured only via XML configuration. Creating dictionaries with executable source via DDL is disabled, otherwise, the DB user would be able to execute arbitrary binary on ClickHouse node.
+
+## Executable Pool {#dicts-external_dicts_dict_sources-executable_pool}
+
+Executable pool allows loading data from pool of processes. This source does not work with dictionary layouts that need to load all data from source. Executable pool works if the dictionary [is stored](external-dicts-dict-layout.md#ways-to-store-dictionaries-in-memory) using `cache`, `complex_key_cache`, `ssd_cache`, `complex_key_ssd_cache`, `direct`, `complex_key_direct` layouts.
+
+Executable pool will spawn pool of processes with specified command and keep them running until they exit. The program should read data from STDIN while it is available and output result to STDOUT, and it can wait for next block of data on STDIN. ClickHouse will not close STDIN after processing a block of data but will pipe another chunk of data when needed. The executable script should be ready for this way of data processing — it should poll STDIN and flush data to STDOUT early.
+
+Example of settings:
+
+``` xml
+<source>
+    <executable_pool>
+        <command><command>while read key; do printf "$key\tData for key $key\n"; done</command</command>
+        <format>TabSeparated</format>
+        <pool_size>10</pool_size>
+        <max_command_execution_time>10<max_command_execution_time>
+        <implicit_key>false</implicit_key>
+    </executable_pool>
+</source>
+```
+
+Setting fields:
+
+-   `command` — The absolute path to the executable file, or the file name (if the program directory is written to `PATH`).
+-   `format` — The file format. All the formats described in “[Formats](../../../interfaces/formats.md#formats)” are supported.
+-   `pool_size` — Size of pool. If 0 is specified as `pool_size` then there is no pool size restrictions. Default value is `16`.
+-   `command_termination_timeout` — executable script should contain main read-write loop. After dictionary is destroyed, pipe is closed, and executable file will have `command_termination_timeout` seconds to shutdown, before ClickHouse will send SIGTERM signal to child process. Specified in seconds. Default value is 10. Optional parameter.
+-   `max_command_execution_time` — Maximum executable script command execution time for processing block of data. Specified in seconds. Default value is 10. Optional parameter.
+-   `command_read_timeout` - timeout for reading data from command stdout in milliseconds. Default value 10000. Optional parameter.
+-   `command_write_timeout` - timeout for writing data to command stdin in milliseconds. Default value 10000. Optional parameter.
+-   `implicit_key` — The executable source file can return only values, and the correspondence to the requested keys is determined implicitly — by the order of rows in the result. Default value is false. Optional parameter.
+-   `execute_direct` - If `execute_direct` = `1`, then `command` will be searched inside user_scripts folder. Additional script arguments can be specified using whitespace separator. Example: `script_name arg1 arg2`. If `execute_direct` = `0`, `command` is passed as argument for `bin/sh -c`. Default value is `1`. Optional parameter.
+-   `send_chunk_header` - controls whether to send row count before sending a chunk of data to process. Optional. Default value is `false`.
+
+That dictionary source can be configured only via XML configuration. Creating dictionaries with executable source via DDL is disabled, otherwise, the DB user would be able to execute arbitrary binary on ClickHouse node.
+
+## Http(s) {#dicts-external_dicts_dict_sources-http}
+
+Working with an HTTP(s) server depends on [how the dictionary is stored in memory](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md). If the dictionary is stored using `cache` and `complex_key_cache`, ClickHouse requests the necessary keys by sending a request via the `POST` method.
+
+Example of settings:
+
+``` xml
+<source>
+    <http>
+        <url>http://[::1]/os.tsv</url>
+        <format>TabSeparated</format>
+        <credentials>
+            <user>user</user>
+            <password>password</password>
+        </credentials>
+        <headers>
+            <header>
+                <name>API-KEY</name>
+                <value>key</value>
+            </header>
+        </headers>
+    </http>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(HTTP(
+    url 'http://[::1]/os.tsv'
+    format 'TabSeparated'
+    credentials(user 'user' password 'password')
+    headers(header(name 'API-KEY' value 'key'))
+))
+```
+
+In order for ClickHouse to access an HTTPS resource, you must [configure openSSL](../../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-openssl) in the server configuration.
+
+Setting fields:
+
+-   `url` – The source URL.
+-   `format` – The file format. All the formats described in “[Formats](../../../interfaces/formats.md#formats)” are supported.
+-   `credentials` – Basic HTTP authentication. Optional parameter.
+-   `user` – Username required for the authentication.
+-   `password` – Password required for the authentication.
+-   `headers` – All custom HTTP headers entries used for the HTTP request. Optional parameter.
+-   `header` – Single HTTP header entry.
+-   `name` – Identifiant name used for the header send on the request.
+-   `value` – Value set for a specific identifiant name.
+
+When creating a dictionary using the DDL command (`CREATE DICTIONARY ...`) remote hosts for HTTP dictionaries are checked against the contents of `remote_url_allow_hosts` section from config to prevent database users to access arbitrary HTTP server.
+
+### Known Vulnerability of the ODBC Dictionary Functionality {#known-vulnerability-of-the-odbc-dictionary-functionality}
+
+:::note    
+When connecting to the database through the ODBC driver connection parameter `Servername` can be substituted. In this case values of `USERNAME` and `PASSWORD` from `odbc.ini` are sent to the remote server and can be compromised.
+:::
+
+**Example of insecure use**
+
+Let’s configure unixODBC for PostgreSQL. Content of `/etc/odbc.ini`:
+
+``` text
+[gregtest]
+Driver = /usr/lib/psqlodbca.so
+Servername = localhost
+PORT = 5432
+DATABASE = test_db
+#OPTION = 3
+USERNAME = test
+PASSWORD = test
+```
+
+If you then make a query such as
+
+``` sql
+SELECT * FROM odbc('DSN=gregtest;Servername=some-server.com', 'test_db');
+```
+
+ODBC driver will send values of `USERNAME` and `PASSWORD` from `odbc.ini` to `some-server.com`.
+
+### Example of Connecting Postgresql {#example-of-connecting-postgresql}
+
+Ubuntu OS.
+
+Installing unixODBC and the ODBC driver for PostgreSQL:
+
+``` bash
+$ sudo apt-get install -y unixodbc odbcinst odbc-postgresql
+```
+
+Configuring `/etc/odbc.ini` (or `~/.odbc.ini` if you signed in under a user that runs ClickHouse):
+
+``` text
+    [DEFAULT]
+    Driver = myconnection
+
+    [myconnection]
+    Description         = PostgreSQL connection to my_db
+    Driver              = PostgreSQL Unicode
+    Database            = my_db
+    Servername          = 127.0.0.1
+    UserName            = username
+    Password            = password
+    Port                = 5432
+    Protocol            = 9.3
+    ReadOnly            = No
+    RowVersioning       = No
+    ShowSystemTables    = No
+    ConnSettings        =
+```
+
+The dictionary configuration in ClickHouse:
+
+``` xml
+<clickhouse>
+    <dictionary>
+        <name>table_name</name>
+        <source>
+            <odbc>
+                <!-- You can specify the following parameters in connection_string: -->
+                <!-- DSN=myconnection;UID=username;PWD=password;HOST=127.0.0.1;PORT=5432;DATABASE=my_db -->
+                <connection_string>DSN=myconnection</connection_string>
+                <table>postgresql_table</table>
+            </odbc>
+        </source>
+        <lifetime>
+            <min>300</min>
+            <max>360</max>
+        </lifetime>
+        <layout>
+            <hashed/>
+        </layout>
+        <structure>
+            <id>
+                <name>id</name>
+            </id>
+            <attribute>
+                <name>some_column</name>
+                <type>UInt64</type>
+                <null_value>0</null_value>
+            </attribute>
+        </structure>
+    </dictionary>
+</clickhouse>
+```
+
+or
+
+``` sql
+CREATE DICTIONARY table_name (
+    id UInt64,
+    some_column UInt64 DEFAULT 0
+)
+PRIMARY KEY id
+SOURCE(ODBC(connection_string 'DSN=myconnection' table 'postgresql_table'))
+LAYOUT(HASHED())
+LIFETIME(MIN 300 MAX 360)
+```
+
+You may need to edit `odbc.ini` to specify the full path to the library with the driver `DRIVER=/usr/local/lib/psqlodbcw.so`.
+
+### Example of Connecting MS SQL Server {#example-of-connecting-ms-sql-server}
+
+Ubuntu OS.
+
+Installing the ODBC driver for connecting to MS SQL:
+
+``` bash
+$ sudo apt-get install tdsodbc freetds-bin sqsh
+```
+
+Configuring the driver:
+
+```bash
+    $ cat /etc/freetds/freetds.conf
+    ...
+
+    [MSSQL]
+    host = 192.168.56.101
+    port = 1433
+    tds version = 7.0
+    client charset = UTF-8
+
+    # test TDS connection
+    $ sqsh -S MSSQL -D database -U user -P password
+
+
+    $ cat /etc/odbcinst.ini
+
+    [FreeTDS]
+    Description     = FreeTDS
+    Driver          = /usr/lib/x86_64-linux-gnu/odbc/libtdsodbc.so
+    Setup           = /usr/lib/x86_64-linux-gnu/odbc/libtdsS.so
+    FileUsage       = 1
+    UsageCount      = 5
+
+    $ cat /etc/odbc.ini
+    # $ cat ~/.odbc.ini # if you signed in under a user that runs ClickHouse
+
+    [MSSQL]
+    Description     = FreeTDS
+    Driver          = FreeTDS
+    Servername      = MSSQL
+    Database        = test
+    UID             = test
+    PWD             = test
+    Port            = 1433
+
+
+    # (optional) test ODBC connection (to use isql-tool install the [unixodbc](https://packages.debian.org/sid/unixodbc)-package)
+    $ isql -v MSSQL "user" "password"
+```
+
+Remarks:
+- to determine the earliest TDS version that is supported by a particular SQL Server version, refer to the product documentation or look at [MS-TDS Product Behavior](https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-tds/135d0ebe-5c4c-4a94-99bf-1811eccb9f4a)
+
+Configuring the dictionary in ClickHouse:
+
+``` xml
+<clickhouse>
+    <dictionary>
+        <name>test</name>
+        <source>
+            <odbc>
+                <table>dict</table>
+                <connection_string>DSN=MSSQL;UID=test;PWD=test</connection_string>
+            </odbc>
+        </source>
+
+        <lifetime>
+            <min>300</min>
+            <max>360</max>
+        </lifetime>
+
+        <layout>
+            <flat />
+        </layout>
+
+        <structure>
+            <id>
+                <name>k</name>
+            </id>
+            <attribute>
+                <name>s</name>
+                <type>String</type>
+                <null_value></null_value>
+            </attribute>
+        </structure>
+    </dictionary>
+</clickhouse>
+```
+
+or
+
+``` sql
+CREATE DICTIONARY test (
+    k UInt64,
+    s String DEFAULT ''
+)
+PRIMARY KEY k
+SOURCE(ODBC(table 'dict' connection_string 'DSN=MSSQL;UID=test;PWD=test'))
+LAYOUT(FLAT())
+LIFETIME(MIN 300 MAX 360)
+```
+
+## DBMS {#dbms}
+
+### ODBC {#dicts-external_dicts_dict_sources-odbc}
+
+You can use this method to connect any database that has an ODBC driver.
+
+Example of settings:
+
+``` xml
+<source>
+    <odbc>
+        <db>DatabaseName</db>
+        <table>ShemaName.TableName</table>
+        <connection_string>DSN=some_parameters</connection_string>
+        <invalidate_query>SQL_QUERY</invalidate_query>
+        <query>SELECT id, value_1, value_2 FROM ShemaName.TableName</query>
+    </odbc>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(ODBC(
+    db 'DatabaseName'
+    table 'SchemaName.TableName'
+    connection_string 'DSN=some_parameters'
+    invalidate_query 'SQL_QUERY'
+    query 'SELECT id, value_1, value_2 FROM db_name.table_name'
+))
+```
+
+Setting fields:
+
+-   `db` – Name of the database. Omit it if the database name is set in the `<connection_string>` parameters.
+-   `table` – Name of the table and schema if exists.
+-   `connection_string` – Connection string.
+-   `invalidate_query` – Query for checking the dictionary status. Optional parameter. Read more in the section [Updating dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md).
+-   `query` – The custom query. Optional parameter.
+
+:::note    
+The `table` and `query` fields cannot be used together. And either one of the `table` or `query` fields must be declared.
+:::
+
+ClickHouse receives quoting symbols from ODBC-driver and quote all settings in queries to driver, so it’s necessary to set table name accordingly to table name case in database.
+
+If you have a problems with encodings when using Oracle, see the corresponding [FAQ](../../../../faq/integration/oracle-odbc.md) item.
+
+### Mysql {#dicts-external_dicts_dict_sources-mysql}
+
+Example of settings:
+
+``` xml
+<source>
+  <mysql>
+      <port>3306</port>
+      <user>clickhouse</user>
+      <password>qwerty</password>
+      <replica>
+          <host>example01-1</host>
+          <priority>1</priority>
+      </replica>
+      <replica>
+          <host>example01-2</host>
+          <priority>1</priority>
+      </replica>
+      <db>db_name</db>
+      <table>table_name</table>
+      <where>id=10</where>
+      <invalidate_query>SQL_QUERY</invalidate_query>
+      <fail_on_connection_loss>true</fail_on_connection_loss>
+      <query>SELECT id, value_1, value_2 FROM db_name.table_name</query>
+  </mysql>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(MYSQL(
+    port 3306
+    user 'clickhouse'
+    password 'qwerty'
+    replica(host 'example01-1' priority 1)
+    replica(host 'example01-2' priority 1)
+    db 'db_name'
+    table 'table_name'
+    where 'id=10'
+    invalidate_query 'SQL_QUERY'
+    fail_on_connection_loss 'true'
+    query 'SELECT id, value_1, value_2 FROM db_name.table_name'
+))
+```
+
+Setting fields:
+
+-   `port` – The port on the MySQL server. You can specify it for all replicas, or for each one individually (inside `<replica>`).
+
+-   `user` – Name of the MySQL user. You can specify it for all replicas, or for each one individually (inside `<replica>`).
+
+-   `password` – Password of the MySQL user. You can specify it for all replicas, or for each one individually (inside `<replica>`).
+
+-   `replica` – Section of replica configurations. There can be multiple sections.
+
+        - `replica/host` – The MySQL host.
+        - `replica/priority` – The replica priority. When attempting to connect, ClickHouse traverses the replicas in order of priority. The lower the number, the higher the priority.
+
+-   `db` – Name of the database.
+
+-   `table` – Name of the table.
+
+-   `where` – The selection criteria. The syntax for conditions is the same as for `WHERE` clause in MySQL, for example, `id > 10 AND id < 20`. Optional parameter.
+
+-   `invalidate_query` – Query for checking the dictionary status. Optional parameter. Read more in the section [Updating dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md).
+
+-   `fail_on_connection_loss` – The configuration parameter that controls behavior of the server on connection loss. If `true`, an exception is thrown immediately if the connection between client and server was lost. If `false`, the ClickHouse server retries to execute the query three times before throwing an exception. Note that retrying leads to increased response times. Default value: `false`.
+
+-   `query` – The custom query. Optional parameter.
+
+:::note    
+The `table` or `where` fields cannot be used together with the `query` field. And either one of the `table` or `query` fields must be declared.
+:::
+
+MySQL can be connected on a local host via sockets. To do this, set `host` and `socket`.
+
+Example of settings:
+
+``` xml
+<source>
+  <mysql>
+      <host>localhost</host>
+      <socket>/path/to/socket/file.sock</socket>
+      <user>clickhouse</user>
+      <password>qwerty</password>
+      <db>db_name</db>
+      <table>table_name</table>
+      <where>id=10</where>
+      <invalidate_query>SQL_QUERY</invalidate_query>
+      <fail_on_connection_loss>true</fail_on_connection_loss>
+	  <query>SELECT id, value_1, value_2 FROM db_name.table_name</query>
+  </mysql>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(MYSQL(
+    host 'localhost'
+    socket '/path/to/socket/file.sock'
+    user 'clickhouse'
+    password 'qwerty'
+    db 'db_name'
+    table 'table_name'
+    where 'id=10'
+    invalidate_query 'SQL_QUERY'
+    fail_on_connection_loss 'true'
+	query 'SELECT id, value_1, value_2 FROM db_name.table_name'
+))
+```
+
+### ClickHouse {#dicts-external_dicts_dict_sources-clickhouse}
+
+Example of settings:
+
+``` xml
+<source>
+    <clickhouse>
+        <host>example01-01-1</host>
+        <port>9000</port>
+        <user>default</user>
+        <password></password>
+        <db>default</db>
+        <table>ids</table>
+        <where>id=10</where>
+        <secure>1</secure>
+		<query>SELECT id, value_1, value_2 FROM default.ids</query>
+    </clickhouse>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(CLICKHOUSE(
+    host 'example01-01-1'
+    port 9000
+    user 'default'
+    password ''
+    db 'default'
+    table 'ids'
+    where 'id=10'
+    secure 1
+	query 'SELECT id, value_1, value_2 FROM default.ids'
+));
+```
+
+Setting fields:
+
+-   `host` – The ClickHouse host. If it is a local host, the query is processed without any network activity. To improve fault tolerance, you can create a [Distributed](../../../engines/table-engines/special/distributed.md) table and enter it in subsequent configurations.
+-   `port` – The port on the ClickHouse server.
+-   `user` – Name of the ClickHouse user.
+-   `password` – Password of the ClickHouse user.
+-   `db` – Name of the database.
+-   `table` – Name of the table.
+-   `where` – The selection criteria. May be omitted.
+-   `invalidate_query` – Query for checking the dictionary status. Optional parameter. Read more in the section [Updating dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md).
+-   `secure` - Use ssl for connection.
+-   `query` – The custom query. Optional parameter.
+
+:::note    
+The `table` or `where` fields cannot be used together with the `query` field. And either one of the `table` or `query` fields must be declared.
+:::
+
+### Mongodb {#dicts-external_dicts_dict_sources-mongodb}
+
+Example of settings:
+
+``` xml
+<source>
+    <mongodb>
+        <host>localhost</host>
+        <port>27017</port>
+        <user></user>
+        <password></password>
+        <db>test</db>
+        <collection>dictionary_source</collection>
+    </mongodb>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(MONGODB(
+    host 'localhost'
+    port 27017
+    user ''
+    password ''
+    db 'test'
+    collection 'dictionary_source'
+))
+```
+
+Setting fields:
+
+-   `host` – The MongoDB host.
+-   `port` – The port on the MongoDB server.
+-   `user` – Name of the MongoDB user.
+-   `password` – Password of the MongoDB user.
+-   `db` – Name of the database.
+-   `collection` – Name of the collection.
+
+### Redis {#dicts-external_dicts_dict_sources-redis}
+
+Example of settings:
+
+``` xml
+<source>
+    <redis>
+        <host>localhost</host>
+        <port>6379</port>
+        <storage_type>simple</storage_type>
+        <db_index>0</db_index>
+    </redis>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(REDIS(
+    host 'localhost'
+    port 6379
+    storage_type 'simple'
+    db_index 0
+))
+```
+
+Setting fields:
+
+-   `host` – The Redis host.
+-   `port` – The port on the Redis server.
+-   `storage_type` – The structure of internal Redis storage using for work with keys. `simple` is for simple sources and for hashed single key sources, `hash_map` is for hashed sources with two keys. Ranged sources and cache sources with complex key are unsupported. May be omitted, default value is `simple`.
+-   `db_index` – The specific numeric index of Redis logical database. May be omitted, default value is 0.
+
+### Cassandra {#dicts-external_dicts_dict_sources-cassandra}
+
+Example of settings:
+
+``` xml
+<source>
+    <cassandra>
+        <host>localhost</host>
+        <port>9042</port>
+        <user>username</user>
+        <password>qwerty123</password>
+        <keyspase>database_name</keyspase>
+        <column_family>table_name</column_family>
+        <allow_filering>1</allow_filering>
+        <partition_key_prefix>1</partition_key_prefix>
+        <consistency>One</consistency>
+        <where>"SomeColumn" = 42</where>
+        <max_threads>8</max_threads>
+        <query>SELECT id, value_1, value_2 FROM database_name.table_name</query>
+    </cassandra>
+</source>
+```
+
+Setting fields:
+
+-   `host` – The Cassandra host or comma-separated list of hosts.
+-   `port` – The port on the Cassandra servers. If not specified, default port 9042 is used.
+-   `user` – Name of the Cassandra user.
+-   `password` – Password of the Cassandra user.
+-   `keyspace` – Name of the keyspace (database).
+-   `column_family` – Name of the column family (table).
+-   `allow_filering` – Flag to allow or not potentially expensive conditions on clustering key columns. Default value is 1.
+-   `partition_key_prefix` – Number of partition key columns in primary key of the Cassandra table. Required for compose key dictionaries. Order of key columns in the dictionary definition must be the same as in Cassandra. Default value is 1 (the first key column is a partition key and other key columns are clustering key).
+-   `consistency` – Consistency level. Possible values: `One`, `Two`, `Three`, `All`, `EachQuorum`, `Quorum`, `LocalQuorum`, `LocalOne`, `Serial`, `LocalSerial`. Default value is `One`.
+-   `where` – Optional selection criteria.
+-   `max_threads` – The maximum number of threads to use for loading data from multiple partitions in compose key dictionaries.
+-   `query` – The custom query. Optional parameter.
+
+:::note    
+The `column_family` or `where` fields cannot be used together with the `query` field. And either one of the `column_family` or `query` fields must be declared.
+:::
+
+### PostgreSQL {#dicts-external_dicts_dict_sources-postgresql}
+
+Example of settings:
+
+``` xml
+<source>
+  <postgresql>
+      <port>5432</port>
+      <user>clickhouse</user>
+      <password>qwerty</password>
+      <db>db_name</db>
+      <table>table_name</table>
+      <where>id=10</where>
+      <invalidate_query>SQL_QUERY</invalidate_query>
+      <query>SELECT id, value_1, value_2 FROM db_name.table_name</query>
+  </postgresql>
+</source>
+```
+
+or
+
+``` sql
+SOURCE(POSTGRESQL(
+    port 5432
+    host 'postgresql-hostname'
+    user 'postgres_user'
+    password 'postgres_password'
+    db 'db_name'
+    table 'table_name'
+    replica(host 'example01-1' port 5432 priority 1)
+    replica(host 'example01-2' port 5432 priority 2)
+    where 'id=10'
+    invalidate_query 'SQL_QUERY'
+    query 'SELECT id, value_1, value_2 FROM db_name.table_name'
+))
+```
+
+Setting fields:
+
+-   `host` – The host on the PostgreSQL server. You can specify it for all replicas, or for each one individually (inside `<replica>`).
+-   `port` – The port on the PostgreSQL server. You can specify it for all replicas, or for each one individually (inside `<replica>`).
+-   `user` – Name of the PostgreSQL user. You can specify it for all replicas, or for each one individually (inside `<replica>`).
+-   `password` – Password of the PostgreSQL user. You can specify it for all replicas, or for each one individually (inside `<replica>`).
+-   `replica` – Section of replica configurations. There can be multiple sections:
+    -   `replica/host` – The PostgreSQL host.
+    -   `replica/port` – The PostgreSQL port.
+    -   `replica/priority` – The replica priority. When attempting to connect, ClickHouse traverses the replicas in order of priority. The lower the number, the higher the priority.
+-   `db` – Name of the database.
+-   `table` – Name of the table.
+-   `where` – The selection criteria. The syntax for conditions is the same as for `WHERE` clause in PostgreSQL. For example, `id > 10 AND id < 20`. Optional parameter.
+-   `invalidate_query` – Query for checking the dictionary status. Optional parameter. Read more in the section [Updating dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md).
+-   `query` – The custom query. Optional parameter.
+
+:::note    
+The `table` or `where` fields cannot be used together with the `query` field. And either one of the `table` or `query` fields must be declared.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md
new file mode 100644
index 00000000000..cc98c9e666a
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md
@@ -0,0 +1,174 @@
+---
+sidebar_position: 44
+sidebar_label: Dictionary Key and Fields
+---
+
+# Dictionary Key and Fields
+
+The `structure` clause describes the dictionary key and fields available for queries.
+
+XML description:
+
+``` xml
+<dictionary>
+    <structure>
+        <id>
+            <name>Id</name>
+        </id>
+
+        <attribute>
+            <!-- Attribute parameters -->
+        </attribute>
+
+        ...
+
+    </structure>
+</dictionary>
+```
+
+Attributes are described in the elements:
+
+-   `<id>` — [Key column](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-key).
+-   `<attribute>` — [Data column](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-attributes). There can be a multiple number of attributes.
+
+DDL query:
+
+``` sql
+CREATE DICTIONARY dict_name (
+    Id UInt64,
+    -- attributes
+)
+PRIMARY KEY Id
+...
+```
+
+Attributes are described in the query body:
+
+-   `PRIMARY KEY` — [Key column](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-key)
+-   `AttrName AttrType` — [Data column](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-attributes). There can be a multiple number of attributes.
+
+## Key {#ext_dict_structure-key}
+
+ClickHouse supports the following types of keys:
+
+-   Numeric key. `UInt64`. Defined in the `<id>` tag or using `PRIMARY KEY` keyword.
+-   Composite key. Set of values of different types. Defined in the tag `<key>` or `PRIMARY KEY` keyword.
+
+An xml structure can contain either `<id>` or `<key>`. DDL-query must contain single `PRIMARY KEY`.
+
+:::warning    
+You must not describe key as an attribute.
+:::
+
+### Numeric Key {#numeric-key}
+
+Type: `UInt64`.
+
+Configuration example:
+
+``` xml
+<id>
+    <name>Id</name>
+</id>
+```
+
+Configuration fields:
+
+-   `name` – The name of the column with keys.
+
+For DDL-query:
+
+``` sql
+CREATE DICTIONARY (
+    Id UInt64,
+    ...
+)
+PRIMARY KEY Id
+...
+```
+
+-   `PRIMARY KEY` – The name of the column with keys.
+
+### Composite Key {#composite-key}
+
+The key can be a `tuple` from any types of fields. The [layout](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md) in this case must be `complex_key_hashed` or `complex_key_cache`.
+
+:::tip
+A composite key can consist of a single element. This makes it possible to use a string as the key, for instance.
+:::
+
+The key structure is set in the element `<key>`. Key fields are specified in the same format as the dictionary [attributes](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md). Example:
+
+``` xml
+<structure>
+    <key>
+        <attribute>
+            <name>field1</name>
+            <type>String</type>
+        </attribute>
+        <attribute>
+            <name>field2</name>
+            <type>UInt32</type>
+        </attribute>
+        ...
+    </key>
+...
+```
+
+or
+
+``` sql
+CREATE DICTIONARY (
+    field1 String,
+    field2 String
+    ...
+)
+PRIMARY KEY field1, field2
+...
+```
+
+For a query to the `dictGet*` function, a tuple is passed as the key. Example: `dictGetString('dict_name', 'attr_name', tuple('string for field1', num_for_field2))`.
+
+## Attributes {#ext_dict_structure-attributes}
+
+Configuration example:
+
+``` xml
+<structure>
+    ...
+    <attribute>
+        <name>Name</name>
+        <type>ClickHouseDataType</type>
+        <null_value></null_value>
+        <expression>rand64()</expression>
+        <hierarchical>true</hierarchical>
+        <injective>true</injective>
+        <is_object_id>true</is_object_id>
+    </attribute>
+</structure>
+```
+
+or
+
+``` sql
+CREATE DICTIONARY somename (
+    Name ClickHouseDataType DEFAULT '' EXPRESSION rand64() HIERARCHICAL INJECTIVE IS_OBJECT_ID
+)
+```
+
+Configuration fields:
+
+| Tag                                                  | Description                                                                                                                                                                                                                                                                                                                                     | Required |
+|------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------|
+| `name`                                               | Column name.                                                                                                                                                                                                                                                                                                                                    | Yes      |
+| `type`                                               | ClickHouse data type: [UInt8](../../../sql-reference/data-types/int-uint.md), [UInt16](../../../sql-reference/data-types/int-uint.md), [UInt32](../../../sql-reference/data-types/int-uint.md), [UInt64](../../../sql-reference/data-types/int-uint.md), [Int8](../../../sql-reference/data-types/int-uint.md), [Int16](../../../sql-reference/data-types/int-uint.md), [Int32](../../../sql-reference/data-types/int-uint.md), [Int64](../../../sql-reference/data-types/int-uint.md), [Float32](../../../sql-reference/data-types/float.md), [Float64](../../../sql-reference/data-types/float.md), [UUID](../../../sql-reference/data-types/uuid.md), [Decimal32](../../../sql-reference/data-types/decimal.md), [Decimal64](../../../sql-reference/data-types/decimal.md), [Decimal128](../../../sql-reference/data-types/decimal.md), [Decimal256](../../../sql-reference/data-types/decimal.md),[Date](../../../sql-reference/data-types/date.md), [Date32](../../../sql-reference/data-types/date32.md), [DateTime](../../../sql-reference/data-types/datetime.md), [DateTime64](../../../sql-reference/data-types/datetime64.md), [String](../../../sql-reference/data-types/string.md), [Array](../../../sql-reference/data-types/array.md).<br/>ClickHouse tries to cast value from dictionary to the specified data type. For example, for MySQL, the field might be `TEXT`, `VARCHAR`, or `BLOB` in the MySQL source table, but it can be uploaded as `String` in ClickHouse.<br/>[Nullable](../../../sql-reference/data-types/nullable.md) is currently supported for [Flat](external-dicts-dict-layout.md#flat), [Hashed](external-dicts-dict-layout.md#dicts-external_dicts_dict_layout-hashed), [ComplexKeyHashed](external-dicts-dict-layout.md#complex-key-hashed), [Direct](external-dicts-dict-layout.md#direct), [ComplexKeyDirect](external-dicts-dict-layout.md#complex-key-direct), [RangeHashed](external-dicts-dict-layout.md#range-hashed), [Polygon](external-dicts-dict-polygon.md), [Cache](external-dicts-dict-layout.md#cache), [ComplexKeyCache](external-dicts-dict-layout.md#complex-key-cache), [SSDCache](external-dicts-dict-layout.md#ssd-cache), [SSDComplexKeyCache](external-dicts-dict-layout.md#complex-key-ssd-cache) dictionaries. In [IPTrie](external-dicts-dict-layout.md#ip-trie) dictionaries `Nullable` types are not supported.       | Yes      |
+| `null_value`                                         | Default value for a non-existing element.<br/>In the example, it is an empty string. [NULL](../../syntax.md#null-literal) value can be used only for the `Nullable` types (see the previous line with types description).                                                                                                                                                                                                                       | Yes      |
+| `expression`                                         | [Expression](../../../sql-reference/syntax.md#syntax-expressions) that ClickHouse executes on the value.<br/>The expression can be a column name in the remote SQL database. Thus, you can use it to create an alias for the remote column.<br/><br/>Default value: no expression.                                                              | No       |
+| <a name="hierarchical-dict-attr"></a> `hierarchical` | If `true`, the attribute contains the value of a parent key for the current key. See [Hierarchical Dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-hierarchical.md).<br/><br/>Default value: `false`.                                                                                               | No       |
+| `injective`                                          | Flag that shows whether the `id -> attribute` image is [injective](https://en.wikipedia.org/wiki/Injective_function).<br/>If `true`, ClickHouse can automatically place after the `GROUP BY` clause the requests to dictionaries with injection. Usually it significantly reduces the amount of such requests.<br/><br/>Default value: `false`. | No       |
+| `is_object_id`                                       | Flag that shows whether the query is executed for a MongoDB document by `ObjectID`.<br/><br/>Default value: `false`.                                                                                                                                                                                                                            | No       |
+
+**See Also**
+
+-   [Functions for working with external dictionaries](../../../sql-reference/functions/ext-dict-functions.md).
+
diff --git a/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict.md b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict.md
new file mode 100644
index 00000000000..bb4fcdab51a
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts-dict.md
@@ -0,0 +1,50 @@
+---
+sidebar_position: 40
+sidebar_label: Configuring an External Dictionary
+---
+
+# Configuring an External Dictionary
+
+If dictionary is configured using xml file, than dictionary configuration has the following structure:
+
+``` xml
+<dictionary>
+    <name>dict_name</name>
+
+    <structure>
+      <!-- Complex key configuration -->
+    </structure>
+
+    <source>
+      <!-- Source configuration -->
+    </source>
+
+    <layout>
+      <!-- Memory layout configuration -->
+    </layout>
+
+    <lifetime>
+      <!-- Lifetime of dictionary in memory -->
+    </lifetime>
+</dictionary>
+```
+
+Corresponding [DDL-query](../../../sql-reference/statements/create/dictionary.md) has the following structure:
+
+``` sql
+CREATE DICTIONARY dict_name
+(
+    ... -- attributes
+)
+PRIMARY KEY ... -- complex or single key configuration
+SOURCE(...) -- Source configuration
+LAYOUT(...) -- Memory layout configuration
+LIFETIME(...) -- Lifetime of dictionary in memory
+```
+
+-   `name` – The identifier that can be used to access the dictionary. Use the characters `[a-zA-Z0-9_\-]`.
+-   [source](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md) — Source of the dictionary.
+-   [layout](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md) — Dictionary layout in memory.
+-   [structure](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md) — Structure of the dictionary . A key and attributes that can be retrieved by this key.
+-   [lifetime](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md) — Frequency of dictionary updates.
+
diff --git a/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts.md b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts.md
new file mode 100644
index 00000000000..d816888f019
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/external-dictionaries/external-dicts.md
@@ -0,0 +1,60 @@
+---
+sidebar_position: 39
+sidebar_label: General Description
+---
+
+# External Dictionaries 
+
+You can add your own dictionaries from various data sources. The data source for a dictionary can be a local text or executable file, an HTTP(s) resource, or another DBMS. For more information, see “[Sources for external dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md)”.
+
+ClickHouse:
+
+-   Fully or partially stores dictionaries in RAM.
+-   Periodically updates dictionaries and dynamically loads missing values. In other words, dictionaries can be loaded dynamically.
+-   Allows to create external dictionaries with xml files or [DDL queries](../../../sql-reference/statements/create/dictionary.md).
+
+The configuration of external dictionaries can be located in one or more xml-files. The path to the configuration is specified in the [dictionaries_config](../../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-dictionaries_config) parameter.
+
+Dictionaries can be loaded at server startup or at first use, depending on the [dictionaries_lazy_load](../../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-dictionaries_lazy_load) setting.
+
+The [dictionaries](../../../operations/system-tables/dictionaries.md#system_tables-dictionaries) system table contains information about dictionaries configured at server. For each dictionary you can find there:
+
+-   Status of the dictionary.
+-   Configuration parameters.
+-   Metrics like amount of RAM allocated for the dictionary or a number of queries since the dictionary was successfully loaded.
+
+The dictionary configuration file has the following format:
+
+``` xml
+<clickhouse>
+    <comment>An optional element with any content. Ignored by the ClickHouse server.</comment>
+
+    <!--Optional element. File name with substitutions-->
+    <include_from>/etc/metrika.xml</include_from>
+
+
+    <dictionary>
+        <!-- Dictionary configuration. -->
+        <!-- There can be any number of <dictionary> sections in the configuration file. -->
+    </dictionary>
+
+</clickhouse>
+```
+
+You can [configure](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict.md) any number of dictionaries in the same file.
+
+[DDL queries for dictionaries](../../../sql-reference/statements/create/dictionary.md) does not require any additional records in server configuration. They allow to work with dictionaries as first-class entities, like tables or views.
+
+:::note    
+You can convert values for a small dictionary by describing it in a `SELECT` query (see the [transform](../../../sql-reference/functions/other-functions.md) function). This functionality is not related to external dictionaries.
+:::
+
+## See Also {#ext-dicts-see-also}
+
+-   [Configuring an External Dictionary](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict.md)
+-   [Storing Dictionaries in Memory](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md)
+-   [Dictionary Updates](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md)
+-   [Sources of External Dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md)
+-   [Dictionary Key and Fields](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md)
+-   [Functions for Working with External Dictionaries](../../../sql-reference/functions/ext-dict-functions.md)
+
diff --git a/docs/en/reference/sql-reference/dictionaries/index.md b/docs/en/reference/sql-reference/dictionaries/index.md
new file mode 100644
index 00000000000..8e54b70eab0
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/index.md
@@ -0,0 +1,16 @@
+---
+sidebar_label: Dictionaries
+sidebar_position: 35
+---
+
+# Dictionaries {#dictionaries}
+
+A dictionary is a mapping (`key -> attributes`) that is convenient for various types of reference lists.
+
+ClickHouse supports special functions for working with dictionaries that can be used in queries. It is easier and more efficient to use dictionaries with functions than a `JOIN` with reference tables.
+
+ClickHouse supports:
+
+-   [Built-in dictionaries](../../sql-reference/dictionaries/internal-dicts.md#internal_dicts) with a specific [set of functions](../../sql-reference/functions/ym-dict-functions.md).
+-   [Plug-in (external) dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md#dicts-external-dicts) with a [set of functions](../../sql-reference/functions/ext-dict-functions.md).
+
diff --git a/docs/en/reference/sql-reference/dictionaries/internal-dicts.md b/docs/en/reference/sql-reference/dictionaries/internal-dicts.md
new file mode 100644
index 00000000000..1996c974412
--- /dev/null
+++ b/docs/en/reference/sql-reference/dictionaries/internal-dicts.md
@@ -0,0 +1,52 @@
+---
+sidebar_position: 39
+sidebar_label: Internal Dictionaries
+---
+
+# Internal Dictionaries {#internal_dicts}
+
+ClickHouse contains a built-in feature for working with a geobase.
+
+This allows you to:
+
+-   Use a region’s ID to get its name in the desired language.
+-   Use a region’s ID to get the ID of a city, area, federal district, country, or continent.
+-   Check whether a region is part of another region.
+-   Get a chain of parent regions.
+
+All the functions support “translocality,” the ability to simultaneously use different perspectives on region ownership. For more information, see the section “Functions for working with web analytics dictionaries”.
+
+The internal dictionaries are disabled in the default package.
+To enable them, uncomment the parameters `path_to_regions_hierarchy_file` and `path_to_regions_names_files` in the server configuration file.
+
+The geobase is loaded from text files.
+
+Place the `regions_hierarchy*.txt` files into the `path_to_regions_hierarchy_file` directory. This configuration parameter must contain the path to the `regions_hierarchy.txt` file (the default regional hierarchy), and the other files (`regions_hierarchy_ua.txt`) must be located in the same directory.
+
+Put the `regions_names_*.txt` files in the `path_to_regions_names_files` directory.
+
+You can also create these files yourself. The file format is as follows:
+
+`regions_hierarchy*.txt`: TabSeparated (no header), columns:
+
+-   region ID (`UInt32`)
+-   parent region ID (`UInt32`)
+-   region type (`UInt8`): 1 - continent, 3 - country, 4 - federal district, 5 - region, 6 - city; other types do not have values
+-   population (`UInt32`) — optional column
+
+`regions_names_*.txt`: TabSeparated (no header), columns:
+
+-   region ID (`UInt32`)
+-   region name (`String`) — Can’t contain tabs or line feeds, even escaped ones.
+
+A flat array is used for storing in RAM. For this reason, IDs shouldn’t be more than a million.
+
+Dictionaries can be updated without restarting the server. However, the set of available dictionaries is not updated.
+For updates, the file modification times are checked. If a file has changed, the dictionary is updated.
+The interval to check for changes is configured in the `builtin_dictionaries_reload_interval` parameter.
+Dictionary updates (other than loading at first use) do not block queries. During updates, queries use the old versions of dictionaries. If an error occurs during an update, the error is written to the server log, and queries continue using the old version of dictionaries.
+
+We recommend periodically updating the dictionaries with the geobase. During an update, generate new files and write them to a separate location. When everything is ready, rename them to the files used by the server.
+
+There are also functions for working with OS identifiers and search engines, but they shouldn’t be used.
+
diff --git a/docs/en/reference/sql-reference/distributed-ddl.md b/docs/en/reference/sql-reference/distributed-ddl.md
new file mode 100644
index 00000000000..e0eae13672a
--- /dev/null
+++ b/docs/en/reference/sql-reference/distributed-ddl.md
@@ -0,0 +1,22 @@
+---
+sidebar_position: 32
+sidebar_label: Distributed DDL
+---
+
+# Distributed DDL Queries (ON CLUSTER Clause) {#distributed-ddl-queries-on-cluster-clause}
+
+By default the `CREATE`, `DROP`, `ALTER`, and `RENAME` queries affect only the current server where they are executed. In a cluster setup, it is possible to run such queries in a distributed manner with the `ON CLUSTER` clause.
+
+For example, the following query creates the `all_hits` `Distributed` table on each host in `cluster`:
+
+``` sql
+CREATE TABLE IF NOT EXISTS all_hits ON CLUSTER cluster (p Date, i Int32) ENGINE = Distributed(cluster, default, hits)
+```
+
+In order to run these queries correctly, each host must have the same cluster definition (to simplify syncing configs, you can use substitutions from ZooKeeper). They must also connect to the ZooKeeper servers.
+
+The local version of the query will eventually be executed on each host in the cluster, even if some hosts are currently not available.
+
+:::warning    
+The order for executing queries within a single host is guaranteed.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/functions/arithmetic-functions.md b/docs/en/reference/sql-reference/functions/arithmetic-functions.md
new file mode 100644
index 00000000000..63c481c9ae6
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/arithmetic-functions.md
@@ -0,0 +1,157 @@
+---
+sidebar_position: 34
+sidebar_label: Arithmetic
+---
+
+# Arithmetic Functions {#arithmetic-functions}
+
+For all arithmetic functions, the result type is calculated as the smallest number type that the result fits in, if there is such a type. The minimum is taken simultaneously based on the number of bits, whether it is signed, and whether it floats. If there are not enough bits, the highest bit type is taken.
+
+Example:
+
+``` sql
+SELECT toTypeName(0), toTypeName(0 + 0), toTypeName(0 + 0 + 0), toTypeName(0 + 0 + 0 + 0)
+```
+
+``` text
+┌─toTypeName(0)─┬─toTypeName(plus(0, 0))─┬─toTypeName(plus(plus(0, 0), 0))─┬─toTypeName(plus(plus(plus(0, 0), 0), 0))─┐
+│ UInt8         │ UInt16                 │ UInt32                          │ UInt64                                   │
+└───────────────┴────────────────────────┴─────────────────────────────────┴──────────────────────────────────────────┘
+```
+
+Arithmetic functions work for any pair of types from UInt8, UInt16, UInt32, UInt64, Int8, Int16, Int32, Int64, Float32, or Float64.
+
+Overflow is produced the same way as in C++.
+
+## plus(a, b), a + b operator {#plusa-b-a-b-operator}
+
+Calculates the sum of the numbers.
+You can also add integer numbers with a date or date and time. In the case of a date, adding an integer means adding the corresponding number of days. For a date with time, it means adding the corresponding number of seconds.
+
+## minus(a, b), a - b operator {#minusa-b-a-b-operator}
+
+Calculates the difference. The result is always signed.
+
+You can also calculate integer numbers from a date or date with time. The idea is the same – see above for ‘plus’.
+
+## multiply(a, b), a \* b operator {#multiplya-b-a-b-operator}
+
+Calculates the product of the numbers.
+
+## divide(a, b), a / b operator {#dividea-b-a-b-operator}
+
+Calculates the quotient of the numbers. The result type is always a floating-point type.
+It is not integer division. For integer division, use the ‘intDiv’ function.
+When dividing by zero you get ‘inf’, ‘-inf’, or ‘nan’.
+
+## intDiv(a, b) {#intdiva-b}
+
+Calculates the quotient of the numbers. Divides into integers, rounding down (by the absolute value).
+An exception is thrown when dividing by zero or when dividing a minimal negative number by minus one.
+
+## intDivOrZero(a, b) {#intdivorzeroa-b}
+
+Differs from ‘intDiv’ in that it returns zero when dividing by zero or when dividing a minimal negative number by minus one.
+
+## modulo(a, b), a % b operator {#modulo}
+
+Calculates the remainder after division.
+If arguments are floating-point numbers, they are pre-converted to integers by dropping the decimal portion.
+The remainder is taken in the same sense as in C++. Truncated division is used for negative numbers.
+An exception is thrown when dividing by zero or when dividing a minimal negative number by minus one.
+
+## moduloOrZero(a, b) {#modulo-or-zero}
+
+Differs from [modulo](#modulo) in that it returns zero when the divisor is zero.
+
+## negate(a), -a operator {#negatea-a-operator}
+
+Calculates a number with the reverse sign. The result is always signed.
+
+## abs(a) {#arithm_func-abs}
+
+Calculates the absolute value of the number (a). That is, if a \< 0, it returns -a. For unsigned types it does not do anything. For signed integer types, it returns an unsigned number.
+
+## gcd(a, b) {#gcda-b}
+
+Returns the greatest common divisor of the numbers.
+An exception is thrown when dividing by zero or when dividing a minimal negative number by minus one.
+
+## lcm(a, b) {#lcma-b}
+
+Returns the least common multiple of the numbers.
+An exception is thrown when dividing by zero or when dividing a minimal negative number by minus one.
+
+## max2 {#max2}
+
+Compares two values and returns the maximum. The returned value is converted to [Float64](../../sql-reference/data-types/float.md).
+
+**Syntax**
+
+```sql
+max2(value1, value2)
+```
+
+**Arguments**
+
+-   `value1` — First value. [Int/UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
+-   `value2` — Second value. [Int/UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   The maximum of two values.
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT max2(-1, 2);
+```
+
+Result:
+
+```text
+┌─max2(-1, 2)─┐
+│           2 │
+└─────────────┘
+```
+
+## min2 {#min2}
+
+Compares two values and returns the minimum. The returned value is converted to [Float64](../../sql-reference/data-types/float.md).
+
+**Syntax**
+
+```sql
+max2(value1, value2)
+```
+
+**Arguments**
+
+-   `value1` — First value. [Int/UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
+-   `value2` — Second value. [Int/UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   The minimum of two values.
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT min2(-1, 2);
+```
+
+Result:
+
+```text
+┌─min2(-1, 2)─┐
+│          -1 │
+└─────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/array-functions.md b/docs/en/reference/sql-reference/functions/array-functions.md
new file mode 100644
index 00000000000..3f96f75e7b8
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/array-functions.md
@@ -0,0 +1,1717 @@
+---
+sidebar_position: 35
+sidebar_label: Arrays
+---
+
+# Array Functions {#functions-for-working-with-arrays}
+
+## empty {#function-empty}
+
+Checks whether the input array is empty.
+
+**Syntax**
+
+``` sql
+empty([x])
+```
+
+An array is considered empty if it does not contain any elements.
+
+:::note    
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [size0](../../sql-reference/data-types/array.md#array-size) subcolumn instead of reading and processing the whole array column. The query `SELECT empty(arr) FROM TABLE;` transforms to `SELECT arr.size0 = 0 FROM TABLE;`.
+:::
+
+The function also works for [strings](string-functions.md#empty) or [UUID](uuid-functions.md#empty).
+
+**Arguments**
+
+-   `[x]` — Input array. [Array](../data-types/array.md).
+
+**Returned value**
+
+-   Returns `1` for an empty array or `0` for a non-empty array.
+
+Type: [UInt8](../data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT empty([]);
+```
+
+Result:
+
+```text
+┌─empty(array())─┐
+│              1 │
+└────────────────┘
+```
+
+## notEmpty {#function-notempty}
+
+Checks whether the input array is non-empty.
+
+**Syntax**
+
+``` sql
+notEmpty([x])
+```
+
+An array is considered non-empty if it contains at least one element.
+
+:::note    
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [size0](../../sql-reference/data-types/array.md#array-size) subcolumn instead of reading and processing the whole array column. The query `SELECT notEmpty(arr) FROM table` transforms to `SELECT arr.size0 != 0 FROM TABLE`.
+:::
+
+The function also works for [strings](string-functions.md#notempty) or [UUID](uuid-functions.md#notempty).
+
+**Arguments**
+
+-   `[x]` — Input array. [Array](../data-types/array.md).
+
+**Returned value**
+
+-   Returns `1` for a non-empty array or `0` for an empty array.
+
+Type: [UInt8](../data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT notEmpty([1,2]);
+```
+
+Result:
+
+```text
+┌─notEmpty([1, 2])─┐
+│                1 │
+└──────────────────┘
+```
+
+## length {#array_functions-length}
+
+Returns the number of items in the array.
+The result type is UInt64.
+The function also works for strings.
+
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [size0](../../sql-reference/data-types/array.md#array-size) subcolumn instead of reading and processing the whole array column. The query `SELECT length(arr) FROM table` transforms to `SELECT arr.size0 FROM TABLE`.
+
+## emptyArrayUInt8, emptyArrayUInt16, emptyArrayUInt32, emptyArrayUInt64 {#emptyarrayuint8-emptyarrayuint16-emptyarrayuint32-emptyarrayuint64}
+
+## emptyArrayInt8, emptyArrayInt16, emptyArrayInt32, emptyArrayInt64 {#emptyarrayint8-emptyarrayint16-emptyarrayint32-emptyarrayint64}
+
+## emptyArrayFloat32, emptyArrayFloat64 {#emptyarrayfloat32-emptyarrayfloat64}
+
+## emptyArrayDate, emptyArrayDateTime {#emptyarraydate-emptyarraydatetime}
+
+## emptyArrayString {#emptyarraystring}
+
+Accepts zero arguments and returns an empty array of the appropriate type.
+
+## emptyArrayToSingle {#emptyarraytosingle}
+
+Accepts an empty array and returns a one-element array that is equal to the default value.
+
+
+## range(end), range(\[start, \] end \[, step\]) {#range}
+
+Returns an array of `UInt` numbers from `start` to `end - 1` by `step`.
+
+**Syntax**
+``` sql
+range([start, ] end [, step])
+```
+
+**Arguments**
+
+-   `start` — The first element of the array. Optional, required if `step` is used. Default value: 0. [UInt](../data-types/int-uint.md)
+-   `end` — The number before which the array is constructed. Required. [UInt](../data-types/int-uint.md)
+-   `step` — Determines the incremental step between each element in the array. Optional. Default value: 1. [UInt](../data-types/int-uint.md)
+
+**Returned value**
+
+-   Array of `UInt` numbers from `start` to `end - 1` by `step`.
+
+**Implementation details**
+
+-   All arguments must be positive values: `start`, `end`, `step` are `UInt` data types, as well as elements of the returned array.
+-   An exception is thrown if query results in arrays with a total length of more than number of elements specified by the [function_range_max_elements_in_block](../../operations/settings/settings.md#settings-function_range_max_elements_in_block) setting.
+
+
+**Examples**
+
+Query:
+``` sql
+SELECT range(5), range(1, 5), range(1, 5, 2);
+```
+Result:
+```txt
+┌─range(5)────┬─range(1, 5)─┬─range(1, 5, 2)─┐
+│ [0,1,2,3,4] │ [1,2,3,4]   │ [1,3]          │
+└─────────────┴─────────────┴────────────────┘
+```
+
+## array(x1, …), operator \[x1, …\] {#arrayx1-operator-x1}
+
+Creates an array from the function arguments.
+The arguments must be constants and have types that have the smallest common type. At least one argument must be passed, because otherwise it isn’t clear which type of array to create. That is, you can’t use this function to create an empty array (to do that, use the ‘emptyArray\*’ function described above).
+Returns an ‘Array(T)’ type result, where ‘T’ is the smallest common type out of the passed arguments.
+
+## arrayConcat {#arrayconcat}
+
+Combines arrays passed as arguments.
+
+``` sql
+arrayConcat(arrays)
+```
+
+**Arguments**
+
+-   `arrays` – Arbitrary number of arguments of [Array](../../sql-reference/data-types/array.md) type.
+    **Example**
+
+<!-- -->
+
+``` sql
+SELECT arrayConcat([1, 2], [3, 4], [5, 6]) AS res
+```
+
+``` text
+┌─res───────────┐
+│ [1,2,3,4,5,6] │
+└───────────────┘
+```
+
+## arrayElement(arr, n), operator arr\[n\] {#arrayelementarr-n-operator-arrn}
+
+Get the element with the index `n` from the array `arr`. `n` must be any integer type.
+Indexes in an array begin from one.
+Negative indexes are supported. In this case, it selects the corresponding element numbered from the end. For example, `arr[-1]` is the last item in the array.
+
+If the index falls outside of the bounds of an array, it returns some default value (0 for numbers, an empty string for strings, etc.), except for the case with a non-constant array and a constant index 0 (in this case there will be an error `Array indices are 1-based`).
+
+## has(arr, elem) {#hasarr-elem}
+
+Checks whether the ‘arr’ array has the ‘elem’ element.
+Returns 0 if the element is not in the array, or 1 if it is.
+
+`NULL` is processed as a value.
+
+``` sql
+SELECT has([1, 2, NULL], NULL)
+```
+
+``` text
+┌─has([1, 2, NULL], NULL)─┐
+│                       1 │
+└─────────────────────────┘
+```
+
+## hasAll {#hasall}
+
+Checks whether one array is a subset of another.
+
+``` sql
+hasAll(set, subset)
+```
+
+**Arguments**
+
+-   `set` – Array of any type with a set of elements.
+-   `subset` – Array of any type with elements that should be tested to be a subset of `set`.
+
+**Return values**
+
+-   `1`, if `set` contains all of the elements from `subset`.
+-   `0`, otherwise.
+
+**Peculiar properties**
+
+-   An empty array is a subset of any array.
+-   `Null` processed as a value.
+-   Order of values in both of arrays does not matter.
+
+**Examples**
+
+`SELECT hasAll([], [])` returns 1.
+
+`SELECT hasAll([1, Null], [Null])` returns 1.
+
+`SELECT hasAll([1.0, 2, 3, 4], [1, 3])` returns 1.
+
+`SELECT hasAll(['a', 'b'], ['a'])` returns 1.
+
+`SELECT hasAll([1], ['a'])` returns 0.
+
+`SELECT hasAll([[1, 2], [3, 4]], [[1, 2], [3, 5]])` returns 0.
+
+## hasAny {#hasany}
+
+Checks whether two arrays have intersection by some elements.
+
+``` sql
+hasAny(array1, array2)
+```
+
+**Arguments**
+
+-   `array1` – Array of any type with a set of elements.
+-   `array2` – Array of any type with a set of elements.
+
+**Return values**
+
+-   `1`, if `array1` and `array2` have one similar element at least.
+-   `0`, otherwise.
+
+**Peculiar properties**
+
+-   `Null` processed as a value.
+-   Order of values in both of arrays does not matter.
+
+**Examples**
+
+`SELECT hasAny([1], [])` returns `0`.
+
+`SELECT hasAny([Null], [Null, 1])` returns `1`.
+
+`SELECT hasAny([-128, 1., 512], [1])` returns `1`.
+
+`SELECT hasAny([[1, 2], [3, 4]], ['a', 'c'])` returns `0`.
+
+`SELECT hasAll([[1, 2], [3, 4]], [[1, 2], [1, 2]])` returns `1`.
+
+## hasSubstr {#hassubstr}
+
+Checks whether all the elements of array2 appear in array1 in the same exact order. Therefore, the function will return 1, if and only if `array1 = prefix + array2 + suffix`.
+
+``` sql
+hasSubstr(array1, array2)
+```
+
+In other words, the functions will check whether all the elements of `array2` are contained in `array1` like
+the `hasAll` function. In addition, it will check that the elements are observed in the same order in both `array1` and `array2`.
+
+For Example:
+- `hasSubstr([1,2,3,4], [2,3])` returns 1. However, `hasSubstr([1,2,3,4], [3,2])` will return `0`.
+- `hasSubstr([1,2,3,4], [1,2,3])` returns 1. However, `hasSubstr([1,2,3,4], [1,2,4])` will return `0`.
+
+**Arguments**
+
+-   `array1` – Array of any type with a set of elements.
+-   `array2` – Array of any type with a set of elements.
+
+**Return values**
+
+-   `1`, if `array1` contains `array2`.
+-   `0`, otherwise.
+
+**Peculiar properties**
+
+-   The function will return `1` if `array2` is empty.
+-   `Null` processed as a value. In other words `hasSubstr([1, 2, NULL, 3, 4], [2,3])` will return `0`. However, `hasSubstr([1, 2, NULL, 3, 4], [2,NULL,3])` will return `1`
+-   Order of values in both of arrays does matter.
+
+**Examples**
+
+`SELECT hasSubstr([], [])` returns 1.
+
+`SELECT hasSubstr([1, Null], [Null])` returns 1.
+
+`SELECT hasSubstr([1.0, 2, 3, 4], [1, 3])` returns 0.
+
+`SELECT hasSubstr(['a', 'b'], ['a'])` returns 1.
+
+`SELECT hasSubstr(['a', 'b' , 'c'], ['a', 'b'])` returns 1.
+
+`SELECT hasSubstr(['a', 'b' , 'c'], ['a', 'c'])` returns 0.
+
+`SELECT hasSubstr([[1, 2], [3, 4], [5, 6]], [[1, 2], [3, 4]])` returns 1.
+
+## indexOf(arr, x) {#indexofarr-x}
+
+Returns the index of the first ‘x’ element (starting from 1) if it is in the array, or 0 if it is not.
+
+Example:
+
+``` sql
+SELECT indexOf([1, 3, NULL, NULL], NULL)
+```
+
+``` text
+┌─indexOf([1, 3, NULL, NULL], NULL)─┐
+│                                 3 │
+└───────────────────────────────────┘
+```
+
+Elements set to `NULL` are handled as normal values.
+
+## arrayCount(\[func,\] arr1, …) {#array-count}
+
+Returns the number of elements in the arr array for which func returns something other than 0. If ‘func’ is not specified, it returns the number of non-zero elements in the array.
+
+Note that the `arrayCount` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument.
+
+## countEqual(arr, x) {#countequalarr-x}
+
+Returns the number of elements in the array equal to x. Equivalent to arrayCount (elem -\> elem = x, arr).
+
+`NULL` elements are handled as separate values.
+
+Example:
+
+``` sql
+SELECT countEqual([1, 2, NULL, NULL], NULL)
+```
+
+``` text
+┌─countEqual([1, 2, NULL, NULL], NULL)─┐
+│                                    2 │
+└──────────────────────────────────────┘
+```
+
+## arrayEnumerate(arr) {#array_functions-arrayenumerate}
+
+Returns the array \[1, 2, 3, …, length (arr) \]
+
+This function is normally used with ARRAY JOIN. It allows counting something just once for each array after applying ARRAY JOIN. Example:
+
+``` sql
+SELECT
+    count() AS Reaches,
+    countIf(num = 1) AS Hits
+FROM test.hits
+ARRAY JOIN
+    GoalsReached,
+    arrayEnumerate(GoalsReached) AS num
+WHERE CounterID = 160656
+LIMIT 10
+```
+
+``` text
+┌─Reaches─┬──Hits─┐
+│   95606 │ 31406 │
+└─────────┴───────┘
+```
+
+In this example, Reaches is the number of conversions (the strings received after applying ARRAY JOIN), and Hits is the number of pageviews (strings before ARRAY JOIN). In this particular case, you can get the same result in an easier way:
+
+``` sql
+SELECT
+    sum(length(GoalsReached)) AS Reaches,
+    count() AS Hits
+FROM test.hits
+WHERE (CounterID = 160656) AND notEmpty(GoalsReached)
+```
+
+``` text
+┌─Reaches─┬──Hits─┐
+│   95606 │ 31406 │
+└─────────┴───────┘
+```
+
+This function can also be used in higher-order functions. For example, you can use it to get array indexes for elements that match a condition.
+
+## arrayEnumerateUniq(arr, …) {#arrayenumerateuniqarr}
+
+Returns an array the same size as the source array, indicating for each element what its position is among elements with the same value.
+For example: arrayEnumerateUniq(\[10, 20, 10, 30\]) = \[1, 1, 2, 1\].
+
+This function is useful when using ARRAY JOIN and aggregation of array elements.
+Example:
+
+``` sql
+SELECT
+    Goals.ID AS GoalID,
+    sum(Sign) AS Reaches,
+    sumIf(Sign, num = 1) AS Visits
+FROM test.visits
+ARRAY JOIN
+    Goals,
+    arrayEnumerateUniq(Goals.ID) AS num
+WHERE CounterID = 160656
+GROUP BY GoalID
+ORDER BY Reaches DESC
+LIMIT 10
+```
+
+``` text
+┌──GoalID─┬─Reaches─┬─Visits─┐
+│   53225 │    3214 │   1097 │
+│ 2825062 │    3188 │   1097 │
+│   56600 │    2803 │    488 │
+│ 1989037 │    2401 │    365 │
+│ 2830064 │    2396 │    910 │
+│ 1113562 │    2372 │    373 │
+│ 3270895 │    2262 │    812 │
+│ 1084657 │    2262 │    345 │
+│   56599 │    2260 │    799 │
+│ 3271094 │    2256 │    812 │
+└─────────┴─────────┴────────┘
+```
+
+In this example, each goal ID has a calculation of the number of conversions (each element in the Goals nested data structure is a goal that was reached, which we refer to as a conversion) and the number of sessions. Without ARRAY JOIN, we would have counted the number of sessions as sum(Sign). But in this particular case, the rows were multiplied by the nested Goals structure, so in order to count each session one time after this, we apply a condition to the value of the arrayEnumerateUniq(Goals.ID) function.
+
+The arrayEnumerateUniq function can take multiple arrays of the same size as arguments. In this case, uniqueness is considered for tuples of elements in the same positions in all the arrays.
+
+``` sql
+SELECT arrayEnumerateUniq([1, 1, 1, 2, 2, 2], [1, 1, 2, 1, 1, 2]) AS res
+```
+
+``` text
+┌─res───────────┐
+│ [1,2,1,1,2,1] │
+└───────────────┘
+```
+
+This is necessary when using ARRAY JOIN with a nested data structure and further aggregation across multiple elements in this structure.
+
+## arrayPopBack {#arraypopback}
+
+Removes the last item from the array.
+
+``` sql
+arrayPopBack(array)
+```
+
+**Arguments**
+
+-   `array` – Array.
+
+**Example**
+
+``` sql
+SELECT arrayPopBack([1, 2, 3]) AS res;
+```
+
+``` text
+┌─res───┐
+│ [1,2] │
+└───────┘
+```
+
+## arrayPopFront {#arraypopfront}
+
+Removes the first item from the array.
+
+``` sql
+arrayPopFront(array)
+```
+
+**Arguments**
+
+-   `array` – Array.
+
+**Example**
+
+``` sql
+SELECT arrayPopFront([1, 2, 3]) AS res;
+```
+
+``` text
+┌─res───┐
+│ [2,3] │
+└───────┘
+```
+
+## arrayPushBack {#arraypushback}
+
+Adds one item to the end of the array.
+
+``` sql
+arrayPushBack(array, single_value)
+```
+
+**Arguments**
+
+-   `array` – Array.
+-   `single_value` – A single value. Only numbers can be added to an array with numbers, and only strings can be added to an array of strings. When adding numbers, ClickHouse automatically sets the `single_value` type for the data type of the array. For more information about the types of data in ClickHouse, see “[Data types](../../sql-reference/data-types/index.md#data_types)”. Can be `NULL`. The function adds a `NULL` element to an array, and the type of array elements converts to `Nullable`.
+
+**Example**
+
+``` sql
+SELECT arrayPushBack(['a'], 'b') AS res;
+```
+
+``` text
+┌─res───────┐
+│ ['a','b'] │
+└───────────┘
+```
+
+## arrayPushFront {#arraypushfront}
+
+Adds one element to the beginning of the array.
+
+``` sql
+arrayPushFront(array, single_value)
+```
+
+**Arguments**
+
+-   `array` – Array.
+-   `single_value` – A single value. Only numbers can be added to an array with numbers, and only strings can be added to an array of strings. When adding numbers, ClickHouse automatically sets the `single_value` type for the data type of the array. For more information about the types of data in ClickHouse, see “[Data types](../../sql-reference/data-types/index.md#data_types)”. Can be `NULL`. The function adds a `NULL` element to an array, and the type of array elements converts to `Nullable`.
+
+**Example**
+
+``` sql
+SELECT arrayPushFront(['b'], 'a') AS res;
+```
+
+``` text
+┌─res───────┐
+│ ['a','b'] │
+└───────────┘
+```
+
+## arrayResize {#arrayresize}
+
+Changes the length of the array.
+
+``` sql
+arrayResize(array, size[, extender])
+```
+
+**Arguments:**
+
+-   `array` — Array.
+-   `size` — Required length of the array.
+    -   If `size` is less than the original size of the array, the array is truncated from the right.
+-   If `size` is larger than the initial size of the array, the array is extended to the right with `extender` values or default values for the data type of the array items.
+-   `extender` — Value for extending an array. Can be `NULL`.
+
+**Returned value:**
+
+An array of length `size`.
+
+**Examples of calls**
+
+``` sql
+SELECT arrayResize([1], 3);
+```
+
+``` text
+┌─arrayResize([1], 3)─┐
+│ [1,0,0]             │
+└─────────────────────┘
+```
+
+``` sql
+SELECT arrayResize([1], 3, NULL);
+```
+
+``` text
+┌─arrayResize([1], 3, NULL)─┐
+│ [1,NULL,NULL]             │
+└───────────────────────────┘
+```
+
+## arraySlice {#arrayslice}
+
+Returns a slice of the array.
+
+``` sql
+arraySlice(array, offset[, length])
+```
+
+**Arguments**
+
+-   `array` – Array of data.
+-   `offset` – Indent from the edge of the array. A positive value indicates an offset on the left, and a negative value is an indent on the right. Numbering of the array items begins with 1.
+-   `length` – The length of the required slice. If you specify a negative value, the function returns an open slice `[offset, array_length - length)`. If you omit the value, the function returns the slice `[offset, the_end_of_array]`.
+
+**Example**
+
+``` sql
+SELECT arraySlice([1, 2, NULL, 4, 5], 2, 3) AS res;
+```
+
+``` text
+┌─res────────┐
+│ [2,NULL,4] │
+└────────────┘
+```
+
+Array elements set to `NULL` are handled as normal values.
+
+## arraySort(\[func,\] arr, …) {#array_functions-sort}
+
+Sorts the elements of the `arr` array in ascending order. If the `func` function is specified, sorting order is determined by the result of the `func` function applied to the elements of the array. If `func` accepts multiple arguments, the `arraySort` function is passed several arrays that the arguments of `func` will correspond to. Detailed examples are shown at the end of `arraySort` description.
+
+Example of integer values sorting:
+
+``` sql
+SELECT arraySort([1, 3, 3, 0]);
+```
+
+``` text
+┌─arraySort([1, 3, 3, 0])─┐
+│ [0,1,3,3]               │
+└─────────────────────────┘
+```
+
+Example of string values sorting:
+
+``` sql
+SELECT arraySort(['hello', 'world', '!']);
+```
+
+``` text
+┌─arraySort(['hello', 'world', '!'])─┐
+│ ['!','hello','world']              │
+└────────────────────────────────────┘
+```
+
+Consider the following sorting order for the `NULL`, `NaN` and `Inf` values:
+
+``` sql
+SELECT arraySort([1, nan, 2, NULL, 3, nan, -4, NULL, inf, -inf]);
+```
+
+``` text
+┌─arraySort([1, nan, 2, NULL, 3, nan, -4, NULL, inf, -inf])─┐
+│ [-inf,-4,1,2,3,inf,nan,nan,NULL,NULL]                     │
+└───────────────────────────────────────────────────────────┘
+```
+
+-   `-Inf` values are first in the array.
+-   `NULL` values are last in the array.
+-   `NaN` values are right before `NULL`.
+-   `Inf` values are right before `NaN`.
+
+Note that `arraySort` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument. In this case, sorting order is determined by the result of the lambda function applied to the elements of the array.
+
+Let’s consider the following example:
+
+``` sql
+SELECT arraySort((x) -> -x, [1, 2, 3]) as res;
+```
+
+``` text
+┌─res─────┐
+│ [3,2,1] │
+└─────────┘
+```
+
+For each element of the source array, the lambda function returns the sorting key, that is, \[1 –\> -1, 2 –\> -2, 3 –\> -3\]. Since the `arraySort` function sorts the keys in ascending order, the result is \[3, 2, 1\]. Thus, the `(x) –> -x` lambda function sets the [descending order](#array_functions-reverse-sort) in a sorting.
+
+The lambda function can accept multiple arguments. In this case, you need to pass the `arraySort` function several arrays of identical length that the arguments of lambda function will correspond to. The resulting array will consist of elements from the first input array; elements from the next input array(s) specify the sorting keys. For example:
+
+``` sql
+SELECT arraySort((x, y) -> y, ['hello', 'world'], [2, 1]) as res;
+```
+
+``` text
+┌─res────────────────┐
+│ ['world', 'hello'] │
+└────────────────────┘
+```
+
+Here, the elements that are passed in the second array (\[2, 1\]) define a sorting key for the corresponding element from the source array (\[‘hello’, ‘world’\]), that is, \[‘hello’ –\> 2, ‘world’ –\> 1\]. Since the lambda function does not use `x`, actual values of the source array do not affect the order in the result. So, ‘hello’ will be the second element in the result, and ‘world’ will be the first.
+
+Other examples are shown below.
+
+``` sql
+SELECT arraySort((x, y) -> y, [0, 1, 2], ['c', 'b', 'a']) as res;
+```
+
+``` text
+┌─res─────┐
+│ [2,1,0] │
+└─────────┘
+```
+
+``` sql
+SELECT arraySort((x, y) -> -y, [0, 1, 2], [1, 2, 3]) as res;
+```
+
+``` text
+┌─res─────┐
+│ [2,1,0] │
+└─────────┘
+```
+
+:::note    
+To improve sorting efficiency, the [Schwartzian transform](https://en.wikipedia.org/wiki/Schwartzian_transform) is used.
+:::
+
+## arrayReverseSort(\[func,\] arr, …) {#array_functions-reverse-sort}
+
+Sorts the elements of the `arr` array in descending order. If the `func` function is specified, `arr` is sorted according to the result of the `func` function applied to the elements of the array, and then the sorted array is reversed. If `func` accepts multiple arguments, the `arrayReverseSort` function is passed several arrays that the arguments of `func` will correspond to. Detailed examples are shown at the end of `arrayReverseSort` description.
+
+Example of integer values sorting:
+
+``` sql
+SELECT arrayReverseSort([1, 3, 3, 0]);
+```
+
+``` text
+┌─arrayReverseSort([1, 3, 3, 0])─┐
+│ [3,3,1,0]                      │
+└────────────────────────────────┘
+```
+
+Example of string values sorting:
+
+``` sql
+SELECT arrayReverseSort(['hello', 'world', '!']);
+```
+
+``` text
+┌─arrayReverseSort(['hello', 'world', '!'])─┐
+│ ['world','hello','!']                     │
+└───────────────────────────────────────────┘
+```
+
+Consider the following sorting order for the `NULL`, `NaN` and `Inf` values:
+
+``` sql
+SELECT arrayReverseSort([1, nan, 2, NULL, 3, nan, -4, NULL, inf, -inf]) as res;
+```
+
+``` text
+┌─res───────────────────────────────────┐
+│ [inf,3,2,1,-4,-inf,nan,nan,NULL,NULL] │
+└───────────────────────────────────────┘
+```
+
+-   `Inf` values are first in the array.
+-   `NULL` values are last in the array.
+-   `NaN` values are right before `NULL`.
+-   `-Inf` values are right before `NaN`.
+
+Note that the `arrayReverseSort` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument. Example is shown below.
+
+``` sql
+SELECT arrayReverseSort((x) -> -x, [1, 2, 3]) as res;
+```
+
+``` text
+┌─res─────┐
+│ [1,2,3] │
+└─────────┘
+```
+
+The array is sorted in the following way:
+
+1.  At first, the source array (\[1, 2, 3\]) is sorted according to the result of the lambda function applied to the elements of the array. The result is an array \[3, 2, 1\].
+2.  Array that is obtained on the previous step, is reversed. So, the final result is \[1, 2, 3\].
+
+The lambda function can accept multiple arguments. In this case, you need to pass the `arrayReverseSort` function several arrays of identical length that the arguments of lambda function will correspond to. The resulting array will consist of elements from the first input array; elements from the next input array(s) specify the sorting keys. For example:
+
+``` sql
+SELECT arrayReverseSort((x, y) -> y, ['hello', 'world'], [2, 1]) as res;
+```
+
+``` text
+┌─res───────────────┐
+│ ['hello','world'] │
+└───────────────────┘
+```
+
+In this example, the array is sorted in the following way:
+
+1.  At first, the source array (\[‘hello’, ‘world’\]) is sorted according to the result of the lambda function applied to the elements of the arrays. The elements that are passed in the second array (\[2, 1\]), define the sorting keys for corresponding elements from the source array. The result is an array \[‘world’, ‘hello’\].
+2.  Array that was sorted on the previous step, is reversed. So, the final result is \[‘hello’, ‘world’\].
+
+Other examples are shown below.
+
+``` sql
+SELECT arrayReverseSort((x, y) -> y, [4, 3, 5], ['a', 'b', 'c']) AS res;
+```
+
+``` text
+┌─res─────┐
+│ [5,3,4] │
+└─────────┘
+```
+
+``` sql
+SELECT arrayReverseSort((x, y) -> -y, [4, 3, 5], [1, 2, 3]) AS res;
+```
+
+``` text
+┌─res─────┐
+│ [4,3,5] │
+└─────────┘
+```
+
+## arrayUniq(arr, …) {#arrayuniqarr}
+
+If one argument is passed, it counts the number of different elements in the array.
+If multiple arguments are passed, it counts the number of different tuples of elements at corresponding positions in multiple arrays.
+
+If you want to get a list of unique items in an array, you can use arrayReduce(‘groupUniqArray’, arr).
+
+## arrayJoin(arr) {#array-functions-join}
+
+A special function. See the section [“ArrayJoin function”](../../sql-reference/functions/array-join.md#functions_arrayjoin).
+
+## arrayDifference {#arraydifference}
+
+Calculates the difference between adjacent array elements. Returns an array where the first element will be 0, the second is the difference between `a[1] - a[0]`, etc. The type of elements in the resulting array is determined by the type inference rules for subtraction (e.g. `UInt8` - `UInt8` = `Int16`).
+
+**Syntax**
+
+``` sql
+arrayDifference(array)
+```
+
+**Arguments**
+
+-   `array` – [Array](https://clickhouse.com/docs/en/data_types/array/).
+
+**Returned values**
+
+Returns an array of differences between adjacent elements.
+
+Type: [UInt\*](https://clickhouse.com/docs/en/data_types/int_uint/#uint-ranges), [Int\*](https://clickhouse.com/docs/en/data_types/int_uint/#int-ranges), [Float\*](https://clickhouse.com/docs/en/data_types/float/).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT arrayDifference([1, 2, 3, 4]);
+```
+
+Result:
+
+``` text
+┌─arrayDifference([1, 2, 3, 4])─┐
+│ [0,1,1,1]                     │
+└───────────────────────────────┘
+```
+
+Example of the overflow due to result type Int64:
+
+Query:
+
+``` sql
+SELECT arrayDifference([0, 10000000000000000000]);
+```
+
+Result:
+
+``` text
+┌─arrayDifference([0, 10000000000000000000])─┐
+│ [0,-8446744073709551616]                   │
+└────────────────────────────────────────────┘
+```
+
+## arrayDistinct {#arraydistinct}
+
+Takes an array, returns an array containing the distinct elements only.
+
+**Syntax**
+
+``` sql
+arrayDistinct(array)
+```
+
+**Arguments**
+
+-   `array` – [Array](https://clickhouse.com/docs/en/data_types/array/).
+
+**Returned values**
+
+Returns an array containing the distinct elements.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT arrayDistinct([1, 2, 2, 3, 1]);
+```
+
+Result:
+
+``` text
+┌─arrayDistinct([1, 2, 2, 3, 1])─┐
+│ [1,2,3]                        │
+└────────────────────────────────┘
+```
+
+## arrayEnumerateDense(arr) {#array_functions-arrayenumeratedense}
+
+Returns an array of the same size as the source array, indicating where each element first appears in the source array.
+
+Example:
+
+``` sql
+SELECT arrayEnumerateDense([10, 20, 10, 30])
+```
+
+``` text
+┌─arrayEnumerateDense([10, 20, 10, 30])─┐
+│ [1,2,1,3]                             │
+└───────────────────────────────────────┘
+```
+
+## arrayIntersect(arr) {#array-functions-arrayintersect}
+
+Takes multiple arrays, returns an array with elements that are present in all source arrays.
+
+Example:
+
+``` sql
+SELECT
+    arrayIntersect([1, 2], [1, 3], [2, 3]) AS no_intersect,
+    arrayIntersect([1, 2], [1, 3], [1, 4]) AS intersect
+```
+
+``` text
+┌─no_intersect─┬─intersect─┐
+│ []           │ [1]       │
+└──────────────┴───────────┘
+```
+
+## arrayReduce {#arrayreduce}
+
+Applies an aggregate function to array elements and returns its result. The name of the aggregation function is passed as a string in single quotes `'max'`, `'sum'`. When using parametric aggregate functions, the parameter is indicated after the function name in parentheses `'uniqUpTo(6)'`.
+
+**Syntax**
+
+``` sql
+arrayReduce(agg_func, arr1, arr2, ..., arrN)
+```
+
+**Arguments**
+
+-   `agg_func` — The name of an aggregate function which should be a constant [string](../../sql-reference/data-types/string.md).
+-   `arr` — Any number of [array](../../sql-reference/data-types/array.md) type columns as the parameters of the aggregation function.
+
+**Returned value**
+
+**Example**
+
+Query:
+
+``` sql
+SELECT arrayReduce('max', [1, 2, 3]);
+```
+
+Result:
+
+``` text
+┌─arrayReduce('max', [1, 2, 3])─┐
+│                             3 │
+└───────────────────────────────┘
+```
+
+If an aggregate function takes multiple arguments, then this function must be applied to multiple arrays of the same size.
+
+Query:
+
+``` sql
+SELECT arrayReduce('maxIf', [3, 5], [1, 0]);
+```
+
+Result:
+
+``` text
+┌─arrayReduce('maxIf', [3, 5], [1, 0])─┐
+│                                    3 │
+└──────────────────────────────────────┘
+```
+
+Example with a parametric aggregate function:
+
+Query:
+
+``` sql
+SELECT arrayReduce('uniqUpTo(3)', [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+```
+
+Result:
+
+``` text
+┌─arrayReduce('uniqUpTo(3)', [1, 2, 3, 4, 5, 6, 7, 8, 9, 10])─┐
+│                                                           4 │
+└─────────────────────────────────────────────────────────────┘
+```
+
+## arrayReduceInRanges {#arrayreduceinranges}
+
+Applies an aggregate function to array elements in given ranges and returns an array containing the result corresponding to each range. The function will return the same result as multiple `arrayReduce(agg_func, arraySlice(arr1, index, length), ...)`.
+
+**Syntax**
+
+``` sql
+arrayReduceInRanges(agg_func, ranges, arr1, arr2, ..., arrN)
+```
+
+**Arguments**
+
+-   `agg_func` — The name of an aggregate function which should be a constant [string](../../sql-reference/data-types/string.md).
+-   `ranges` — The ranges to aggretate which should be an [array](../../sql-reference/data-types/array.md) of [tuples](../../sql-reference/data-types/tuple.md) which containing the index and the length of each range.
+-   `arr` — Any number of [Array](../../sql-reference/data-types/array.md) type columns as the parameters of the aggregation function.
+
+**Returned value**
+
+-   Array containing results of the aggregate function over specified ranges.
+
+Type: [Array](../../sql-reference/data-types/array.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT arrayReduceInRanges(
+    'sum',
+    [(1, 5), (2, 3), (3, 4), (4, 4)],
+    [1000000, 200000, 30000, 4000, 500, 60, 7]
+) AS res
+```
+
+Result:
+
+``` text
+┌─res─────────────────────────┐
+│ [1234500,234000,34560,4567] │
+└─────────────────────────────┘
+```
+
+## arrayReverse(arr) {#arrayreverse}
+
+Returns an array of the same size as the original array containing the elements in reverse order.
+
+Example:
+
+``` sql
+SELECT arrayReverse([1, 2, 3])
+```
+
+``` text
+┌─arrayReverse([1, 2, 3])─┐
+│ [3,2,1]                 │
+└─────────────────────────┘
+```
+
+## reverse(arr) {#array-functions-reverse}
+
+Synonym for [“arrayReverse”](#arrayreverse)
+
+## arrayFlatten {#arrayflatten}
+
+Converts an array of arrays to a flat array.
+
+Function:
+
+-   Applies to any depth of nested arrays.
+-   Does not change arrays that are already flat.
+
+The flattened array contains all the elements from all source arrays.
+
+**Syntax**
+
+``` sql
+flatten(array_of_arrays)
+```
+
+Alias: `flatten`.
+
+**Arguments**
+
+-   `array_of_arrays` — [Array](../../sql-reference/data-types/array.md) of arrays. For example, `[[1,2,3], [4,5]]`.
+
+**Examples**
+
+``` sql
+SELECT flatten([[[1]], [[2], [3]]]);
+```
+
+``` text
+┌─flatten(array(array([1]), array([2], [3])))─┐
+│ [1,2,3]                                     │
+└─────────────────────────────────────────────┘
+```
+
+## arrayCompact {#arraycompact}
+
+Removes consecutive duplicate elements from an array. The order of result values is determined by the order in the source array.
+
+**Syntax**
+
+``` sql
+arrayCompact(arr)
+```
+
+**Arguments**
+
+`arr` — The [array](../../sql-reference/data-types/array.md) to inspect.
+
+**Returned value**
+
+The array without duplicate.
+
+Type: `Array`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT arrayCompact([1, 1, nan, nan, 2, 3, 3, 3]);
+```
+
+Result:
+
+``` text
+┌─arrayCompact([1, 1, nan, nan, 2, 3, 3, 3])─┐
+│ [1,nan,nan,2,3]                            │
+└────────────────────────────────────────────┘
+```
+
+## arrayZip {#arrayzip}
+
+Combines multiple arrays into a single array. The resulting array contains the corresponding elements of the source arrays grouped into tuples in the listed order of arguments.
+
+**Syntax**
+
+``` sql
+arrayZip(arr1, arr2, ..., arrN)
+```
+
+**Arguments**
+
+-   `arrN` — [Array](../../sql-reference/data-types/array.md).
+
+The function can take any number of arrays of different types. All the input arrays must be of equal size.
+
+**Returned value**
+
+-   Array with elements from the source arrays grouped into [tuples](../../sql-reference/data-types/tuple.md). Data types in the tuple are the same as types of the input arrays and in the same order as arrays are passed.
+
+Type: [Array](../../sql-reference/data-types/array.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT arrayZip(['a', 'b', 'c'], [5, 2, 1]);
+```
+
+Result:
+
+``` text
+┌─arrayZip(['a', 'b', 'c'], [5, 2, 1])─┐
+│ [('a',5),('b',2),('c',1)]            │
+└──────────────────────────────────────┘
+```
+
+## arrayAUC {#arrayauc}
+
+Calculate AUC (Area Under the Curve, which is a concept in machine learning, see more details: https://en.wikipedia.org/wiki/Receiver_operating_characteristic#Area_under_the_curve).
+
+**Syntax**
+
+``` sql
+arrayAUC(arr_scores, arr_labels)
+```
+
+**Arguments**
+
+- `arr_scores` — scores prediction model gives.
+- `arr_labels` — labels of samples, usually 1 for positive sample and 0 for negtive sample.
+
+**Returned value**
+
+Returns AUC value with type Float64.
+
+**Example**
+
+Query:
+
+``` sql
+select arrayAUC([0.1, 0.4, 0.35, 0.8], [0, 0, 1, 1]);
+```
+
+Result:
+
+``` text
+┌─arrayAUC([0.1, 0.4, 0.35, 0.8], [0, 0, 1, 1])─┐
+│                                          0.75 │
+└───────────────────────────────────────────────┘
+```
+
+## arrayMap(func, arr1, …) {#array-map}
+
+Returns an array obtained from the original application of the `func` function to each element in the `arr` array.
+
+Examples:
+
+``` sql
+SELECT arrayMap(x -> (x + 2), [1, 2, 3]) as res;
+```
+
+``` text
+┌─res─────┐
+│ [3,4,5] │
+└─────────┘
+```
+
+The following example shows how to create a tuple of elements from different arrays:
+
+``` sql
+SELECT arrayMap((x, y) -> (x, y), [1, 2, 3], [4, 5, 6]) AS res
+```
+
+``` text
+┌─res─────────────────┐
+│ [(1,4),(2,5),(3,6)] │
+└─────────────────────┘
+```
+
+Note that the `arrayMap` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arrayFilter(func, arr1, …) {#array-filter}
+
+Returns an array containing only the elements in `arr1` for which `func` returns something other than 0.
+
+Examples:
+
+``` sql
+SELECT arrayFilter(x -> x LIKE '%World%', ['Hello', 'abc World']) AS res
+```
+
+``` text
+┌─res───────────┐
+│ ['abc World'] │
+└───────────────┘
+```
+
+``` sql
+SELECT
+    arrayFilter(
+        (i, x) -> x LIKE '%World%',
+        arrayEnumerate(arr),
+        ['Hello', 'abc World'] AS arr)
+    AS res
+```
+
+``` text
+┌─res─┐
+│ [2] │
+└─────┘
+```
+
+Note that the `arrayFilter` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arrayFill(func, arr1, …) {#array-fill}
+
+Scan through `arr1` from the first element to the last element and replace `arr1[i]` by `arr1[i - 1]` if `func` returns 0. The first element of `arr1` will not be replaced.
+
+Examples:
+
+``` sql
+SELECT arrayFill(x -> not isNull(x), [1, null, 3, 11, 12, null, null, 5, 6, 14, null, null]) AS res
+```
+
+``` text
+┌─res──────────────────────────────┐
+│ [1,1,3,11,12,12,12,5,6,14,14,14] │
+└──────────────────────────────────┘
+```
+
+Note that the `arrayFill` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arrayReverseFill(func, arr1, …) {#array-reverse-fill}
+
+Scan through `arr1` from the last element to the first element and replace `arr1[i]` by `arr1[i + 1]` if `func` returns 0. The last element of `arr1` will not be replaced.
+
+Examples:
+
+``` sql
+SELECT arrayReverseFill(x -> not isNull(x), [1, null, 3, 11, 12, null, null, 5, 6, 14, null, null]) AS res
+```
+
+``` text
+┌─res────────────────────────────────┐
+│ [1,3,3,11,12,5,5,5,6,14,NULL,NULL] │
+└────────────────────────────────────┘
+```
+
+Note that the `arrayReverseFill` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arraySplit(func, arr1, …) {#array-split}
+
+Split `arr1` into multiple arrays. When `func` returns something other than 0, the array will be split on the left hand side of the element. The array will not be split before the first element.
+
+Examples:
+
+``` sql
+SELECT arraySplit((x, y) -> y, [1, 2, 3, 4, 5], [1, 0, 0, 1, 0]) AS res
+```
+
+``` text
+┌─res─────────────┐
+│ [[1,2,3],[4,5]] │
+└─────────────────┘
+```
+
+Note that the `arraySplit` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arrayReverseSplit(func, arr1, …) {#array-reverse-split}
+
+Split `arr1` into multiple arrays. When `func` returns something other than 0, the array will be split on the right hand side of the element. The array will not be split after the last element.
+
+Examples:
+
+``` sql
+SELECT arrayReverseSplit((x, y) -> y, [1, 2, 3, 4, 5], [1, 0, 0, 1, 0]) AS res
+```
+
+``` text
+┌─res───────────────┐
+│ [[1],[2,3,4],[5]] │
+└───────────────────┘
+```
+
+Note that the `arrayReverseSplit` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arrayExists(\[func,\] arr1, …) {#arrayexistsfunc-arr1}
+
+Returns 1 if there is at least one element in `arr` for which `func` returns something other than 0. Otherwise, it returns 0.
+
+Note that the `arrayExists` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument.
+
+## arrayAll(\[func,\] arr1, …) {#arrayallfunc-arr1}
+
+Returns 1 if `func` returns something other than 0 for all the elements in `arr`. Otherwise, it returns 0.
+
+Note that the `arrayAll` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument.
+
+## arrayFirst(func, arr1, …) {#array-first}
+
+Returns the first element in the `arr1` array for which `func` returns something other than 0.
+
+Note that the `arrayFirst` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arrayLast(func, arr1, …) {#array-last}
+
+Returns the last element in the `arr1` array for which `func` returns something other than 0.
+
+Note that the `arrayLast` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arrayFirstIndex(func, arr1, …) {#array-first-index}
+
+Returns the index of the first element in the `arr1` array for which `func` returns something other than 0.
+
+Note that the `arrayFirstIndex` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arrayLastIndex(func, arr1, …) {#array-last-index}
+
+Returns the index of the last element in the `arr1` array for which `func` returns something other than 0.
+
+Note that the `arrayLastIndex` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
+
+## arrayMin {#array-min}
+
+Returns the minimum of elements in the source array.
+
+If the `func` function is specified, returns the mininum of elements converted by this function.
+
+Note that the `arrayMin` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument.
+
+**Syntax**
+
+```sql
+arrayMin([func,] arr)
+```
+
+**Arguments**
+
+-   `func` — Function. [Expression](../../sql-reference/data-types/special-data-types/expression.md).
+-   `arr` — Array. [Array](../../sql-reference/data-types/array.md).
+
+**Returned value**
+
+-   The minimum of function values (or the array minimum).
+
+Type: if `func` is specified, matches `func` return value type, else matches the array elements type.
+
+**Examples**
+
+Query:
+
+```sql
+SELECT arrayMin([1, 2, 4]) AS res;
+```
+
+Result:
+
+```text
+┌─res─┐
+│   1 │
+└─────┘
+```
+
+Query:
+
+```sql
+SELECT arrayMin(x -> (-x), [1, 2, 4]) AS res;
+```
+
+Result:
+
+```text
+┌─res─┐
+│  -4 │
+└─────┘
+```
+
+## arrayMax {#array-max}
+
+Returns the maximum of elements in the source array.
+
+If the `func` function is specified, returns the maximum of elements converted by this function.
+
+Note that the `arrayMax` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument.
+
+**Syntax**
+
+```sql
+arrayMax([func,] arr)
+```
+
+**Arguments**
+
+-   `func` — Function. [Expression](../../sql-reference/data-types/special-data-types/expression.md).
+-   `arr` — Array. [Array](../../sql-reference/data-types/array.md).
+
+**Returned value**
+
+-   The maximum of function values (or the array maximum).
+
+Type: if `func` is specified, matches `func` return value type, else matches the array elements type.
+
+**Examples**
+
+Query:
+
+```sql
+SELECT arrayMax([1, 2, 4]) AS res;
+```
+
+Result:
+
+```text
+┌─res─┐
+│   4 │
+└─────┘
+```
+
+Query:
+
+```sql
+SELECT arrayMax(x -> (-x), [1, 2, 4]) AS res;
+```
+
+Result:
+
+```text
+┌─res─┐
+│  -1 │
+└─────┘
+```
+
+## arraySum {#array-sum}
+
+Returns the sum of elements in the source array.
+
+If the `func` function is specified, returns the sum of elements converted by this function.
+
+Note that the `arraySum` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument.
+
+**Syntax**
+
+```sql
+arraySum([func,] arr)
+```
+
+**Arguments**
+
+-   `func` — Function. [Expression](../../sql-reference/data-types/special-data-types/expression.md).
+-   `arr` — Array. [Array](../../sql-reference/data-types/array.md).
+
+**Returned value**
+
+-   The sum of the function values (or the array sum).
+
+Type: for decimal numbers in source array (or for converted values, if `func` is specified) — [Decimal128](../../sql-reference/data-types/decimal.md), for floating point numbers — [Float64](../../sql-reference/data-types/float.md), for numeric unsigned — [UInt64](../../sql-reference/data-types/int-uint.md), and for numeric signed — [Int64](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+Query:
+
+```sql
+SELECT arraySum([2, 3]) AS res;
+```
+
+Result:
+
+```text
+┌─res─┐
+│   5 │
+└─────┘
+```
+
+Query:
+
+```sql
+SELECT arraySum(x -> x*x, [2, 3]) AS res;
+```
+
+Result:
+
+```text
+┌─res─┐
+│  13 │
+└─────┘
+```
+
+## arrayAvg {#array-avg}
+
+Returns the average of elements in the source array.
+
+If the `func` function is specified, returns the average of elements converted by this function.
+
+Note that the `arrayAvg` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument.
+
+**Syntax**
+
+```sql
+arrayAvg([func,] arr)
+```
+
+**Arguments**
+
+-   `func` — Function. [Expression](../../sql-reference/data-types/special-data-types/expression.md).
+-   `arr` — Array. [Array](../../sql-reference/data-types/array.md).
+
+**Returned value**
+
+-   The average of function values (or the array average).
+
+Type: [Float64](../../sql-reference/data-types/float.md).
+
+**Examples**
+
+Query:
+
+```sql
+SELECT arrayAvg([1, 2, 4]) AS res;
+```
+
+Result:
+
+```text
+┌────────────────res─┐
+│ 2.3333333333333335 │
+└────────────────────┘
+```
+
+Query:
+
+```sql
+SELECT arrayAvg(x -> (x * x), [2, 4]) AS res;
+```
+
+Result:
+
+```text
+┌─res─┐
+│  10 │
+└─────┘
+```
+
+## arrayCumSum(\[func,\] arr1, …) {#arraycumsumfunc-arr1}
+
+Returns an array of partial sums of elements in the source array (a running sum). If the `func` function is specified, then the values of the array elements are converted by this function before summing.
+
+Example:
+
+``` sql
+SELECT arrayCumSum([1, 1, 1, 1]) AS res
+```
+
+``` text
+┌─res──────────┐
+│ [1, 2, 3, 4] │
+└──────────────┘
+```
+
+Note that the `arrayCumSum` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument.
+
+## arrayCumSumNonNegative(arr) {#arraycumsumnonnegativearr}
+
+Same as `arrayCumSum`, returns an array of partial sums of elements in the source array (a running sum). Different `arrayCumSum`, when then returned value contains a value less than zero, the value is replace with zero and the subsequent calculation is performed with zero parameters. For example:
+
+``` sql
+SELECT arrayCumSumNonNegative([1, 1, -4, 1]) AS res
+```
+
+``` text
+┌─res───────┐
+│ [1,2,0,1] │
+└───────────┘
+```
+Note that the `arraySumNonNegative` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You can pass a lambda function to it as the first argument.
+
+## arrayProduct {#arrayproduct}
+
+Multiplies elements of an [array](../../sql-reference/data-types/array.md).
+
+**Syntax**
+
+``` sql
+arrayProduct(arr)
+```
+
+**Arguments**
+
+-   `arr` — [Array](../../sql-reference/data-types/array.md) of numeric values.
+
+**Returned value**
+
+-   A product of array's elements.
+
+Type: [Float64](../../sql-reference/data-types/float.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT arrayProduct([1,2,3,4,5,6]) as res;
+```
+
+Result:
+
+``` text
+┌─res───┐
+│ 720   │
+└───────┘
+```
+
+Query:
+
+``` sql
+SELECT arrayProduct([toDecimal64(1,8), toDecimal64(2,8), toDecimal64(3,8)]) as res, toTypeName(res);
+```
+
+Return value type is always [Float64](../../sql-reference/data-types/float.md). Result:
+
+``` text
+┌─res─┬─toTypeName(arrayProduct(array(toDecimal64(1, 8), toDecimal64(2, 8), toDecimal64(3, 8))))─┐
+│ 6   │ Float64                                                                                  │
+└─────┴──────────────────────────────────────────────────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/array-join.md b/docs/en/reference/sql-reference/functions/array-join.md
new file mode 100644
index 00000000000..24d9c2b08d8
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/array-join.md
@@ -0,0 +1,34 @@
+---
+sidebar_position: 61
+sidebar_label: arrayJoin
+---
+
+# arrayJoin function {#functions_arrayjoin}
+
+This is a very unusual function.
+
+Normal functions do not change a set of rows, but just change the values in each row (map).
+Aggregate functions compress a set of rows (fold or reduce).
+The ‘arrayJoin’ function takes each row and generates a set of rows (unfold).
+
+This function takes an array as an argument, and propagates the source row to multiple rows for the number of elements in the array.
+All the values in columns are simply copied, except the values in the column where this function is applied; it is replaced with the corresponding array value.
+
+A query can use multiple `arrayJoin` functions. In this case, the transformation is performed multiple times.
+
+Note the ARRAY JOIN syntax in the SELECT query, which provides broader possibilities.
+
+Example:
+
+``` sql
+SELECT arrayJoin([1, 2, 3] AS src) AS dst, 'Hello', src
+```
+
+``` text
+┌─dst─┬─\'Hello\'─┬─src─────┐
+│   1 │ Hello     │ [1,2,3] │
+│   2 │ Hello     │ [1,2,3] │
+│   3 │ Hello     │ [1,2,3] │
+└─────┴───────────┴─────────┘
+```
+
diff --git a/docs/en/reference/sql-reference/functions/bit-functions.md b/docs/en/reference/sql-reference/functions/bit-functions.md
new file mode 100644
index 00000000000..c23c5ac5431
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/bit-functions.md
@@ -0,0 +1,447 @@
+---
+sidebar_position: 48
+sidebar_label: Bit
+---
+
+# Bit Functions {#bit-functions}
+
+Bit functions work for any pair of types from `UInt8`, `UInt16`, `UInt32`, `UInt64`, `Int8`, `Int16`, `Int32`, `Int64`, `Float32`, or `Float64`. Some functions support `String` and `FixedString` types.
+
+The result type is an integer with bits equal to the maximum bits of its arguments. If at least one of the arguments is signed, the result is a signed number. If an argument is a floating-point number, it is cast to Int64.
+
+## bitAnd(a, b) {#bitanda-b}
+
+## bitOr(a, b) {#bitora-b}
+
+## bitXor(a, b) {#bitxora-b}
+
+## bitNot(a) {#bitnota}
+
+## bitShiftLeft(a, b) {#bitshiftlefta-b}
+
+Shifts the binary representation of a value to the left by a specified number of bit positions.
+
+A `FixedString` or a `String` is treated as a single multibyte value.
+
+Bits of a `FixedString` value are lost as they are shifted out. On the contrary, a `String` value is extended with additional bytes, so no bits are lost.
+
+**Syntax**
+
+``` sql
+bitShiftLeft(a, b)
+```
+
+**Arguments**
+
+-   `a` — A value to shift. [Integer types](../../sql-reference/data-types/int-uint.md), [String](../../sql-reference/data-types/string.md) or [FixedString](../../sql-reference/data-types/fixedstring.md).
+-   `b` — The number of shift positions. [Unsigned integer types](../../sql-reference/data-types/int-uint.md), 64 bit types or less are allowed.
+
+**Returned value**
+
+-   Shifted value.
+
+The type of the returned value is the same as the type of the input value.
+
+**Example**
+
+In the following queries [bin](encoding-functions.md#bin) and [hex](encoding-functions.md#hex) functions are used to show bits of shifted values.
+
+``` sql
+SELECT 99 AS a, bin(a), bitShiftLeft(a, 2) AS a_shifted, bin(a_shifted);
+SELECT 'abc' AS a, hex(a), bitShiftLeft(a, 4) AS a_shifted, hex(a_shifted);
+SELECT toFixedString('abc', 3) AS a, hex(a), bitShiftLeft(a, 4) AS a_shifted, hex(a_shifted);
+```
+
+Result:
+
+``` text
+┌──a─┬─bin(99)──┬─a_shifted─┬─bin(bitShiftLeft(99, 2))─┐
+│ 99 │ 01100011 │       140 │ 10001100                 │
+└────┴──────────┴───────────┴──────────────────────────┘
+┌─a───┬─hex('abc')─┬─a_shifted─┬─hex(bitShiftLeft('abc', 4))─┐
+│ abc │ 616263     │ &0        │ 06162630                    │
+└─────┴────────────┴───────────┴─────────────────────────────┘
+┌─a───┬─hex(toFixedString('abc', 3))─┬─a_shifted─┬─hex(bitShiftLeft(toFixedString('abc', 3), 4))─┐
+│ abc │ 616263                       │ &0        │ 162630                                        │
+└─────┴──────────────────────────────┴───────────┴───────────────────────────────────────────────┘
+```
+
+## bitShiftRight(a, b) {#bitshiftrighta-b}
+
+Shifts the binary representation of a value to the right by a specified number of bit positions.
+
+A `FixedString` or a `String` is treated as a single multibyte value. Note that the length of a `String` value is reduced as bits are shifted out.
+
+**Syntax**
+
+``` sql
+bitShiftRight(a, b)
+```
+
+**Arguments**
+
+-   `a` — A value to shift. [Integer types](../../sql-reference/data-types/int-uint.md), [String](../../sql-reference/data-types/string.md) or [FixedString](../../sql-reference/data-types/fixedstring.md).
+-   `b` — The number of shift positions. [Unsigned integer types](../../sql-reference/data-types/int-uint.md), 64 bit types or less are allowed.
+
+**Returned value**
+
+-   Shifted value.
+
+The type of the returned value is the same as the type of the input value.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT 101 AS a, bin(a), bitShiftRight(a, 2) AS a_shifted, bin(a_shifted);
+SELECT 'abc' AS a, hex(a), bitShiftRight(a, 12) AS a_shifted, hex(a_shifted);
+SELECT toFixedString('abc', 3) AS a, hex(a), bitShiftRight(a, 12) AS a_shifted, hex(a_shifted);
+```
+
+Result:
+
+``` text
+┌───a─┬─bin(101)─┬─a_shifted─┬─bin(bitShiftRight(101, 2))─┐
+│ 101 │ 01100101 │        25 │ 00011001                   │
+└─────┴──────────┴───────────┴────────────────────────────┘
+┌─a───┬─hex('abc')─┬─a_shifted─┬─hex(bitShiftRight('abc', 12))─┐
+│ abc │ 616263     │           │ 0616                          │
+└─────┴────────────┴───────────┴───────────────────────────────┘
+┌─a───┬─hex(toFixedString('abc', 3))─┬─a_shifted─┬─hex(bitShiftRight(toFixedString('abc', 3), 12))─┐
+│ abc │ 616263                       │           │ 000616                                          │
+└─────┴──────────────────────────────┴───────────┴─────────────────────────────────────────────────┘
+```
+
+## bitRotateLeft(a, b) {#bitrotatelefta-b}
+
+## bitRotateRight(a, b) {#bitrotaterighta-b}
+
+## bitSlice(s, offset, length)
+
+Returns a substring starting with the bit from the ‘offset’ index that is ‘length’ bits long. bits indexing starts from
+1
+
+**Syntax**
+
+``` sql
+bitSlice(s, offset[, length])
+```
+
+**Arguments**
+
+- `s` — s is [String](../../sql-reference/data-types/string.md)
+  or [FixedString](../../sql-reference/data-types/fixedstring.md).
+- `offset` — The start index with bit, A positive value indicates an offset on the left, and a negative value is an
+  indent on the right. Numbering of the bits begins with 1.
+- `length` — The length of substring with bit. If you specify a negative value, the function returns an open substring [
+  offset, array_length - length). If you omit the value, the function returns the substring [offset, the_end_string]. 
+  If length exceeds s, it will be truncate.If length isn't multiple of 8, will fill 0 on the right.
+
+**Returned value**
+
+- The substring. [String](../../sql-reference/data-types/string.md)
+
+**Example**
+
+Query:
+
+``` sql
+select bin('Hello'), bin(bitSlice('Hello', 1, 8))
+select bin('Hello'), bin(bitSlice('Hello', 1, 2))
+select bin('Hello'), bin(bitSlice('Hello', 1, 9))
+select bin('Hello'), bin(bitSlice('Hello', -4, 8))
+```
+
+Result:
+
+``` text
+┌─bin('Hello')─────────────────────────────┬─bin(bitSlice('Hello', 1, 8))─┐
+│ 0100100001100101011011000110110001101111 │ 01001000                     │
+└──────────────────────────────────────────┴──────────────────────────────┘
+┌─bin('Hello')─────────────────────────────┬─bin(bitSlice('Hello', 1, 2))─┐
+│ 0100100001100101011011000110110001101111 │ 01000000                     │
+└──────────────────────────────────────────┴──────────────────────────────┘
+┌─bin('Hello')─────────────────────────────┬─bin(bitSlice('Hello', 1, 9))─┐
+│ 0100100001100101011011000110110001101111 │ 0100100000000000             │
+└──────────────────────────────────────────┴──────────────────────────────┘
+┌─bin('Hello')─────────────────────────────┬─bin(bitSlice('Hello', -4, 8))─┐
+│ 0100100001100101011011000110110001101111 │ 11110000                      │
+└──────────────────────────────────────────┴───────────────────────────────┘
+```
+
+## bitTest {#bittest}
+
+Takes any integer and converts it into [binary form](https://en.wikipedia.org/wiki/Binary_number), returns the value of a bit at specified position. The countdown starts from 0 from the right to the left.
+
+**Syntax**
+
+``` sql
+SELECT bitTest(number, index)
+```
+
+**Arguments**
+
+-   `number` – Integer number.
+-   `index` – Position of bit.
+
+**Returned values**
+
+Returns a value of bit at specified position.
+
+Type: `UInt8`.
+
+**Example**
+
+For example, the number 43 in base-2 (binary) numeral system is 101011.
+
+Query:
+
+``` sql
+SELECT bitTest(43, 1);
+```
+
+Result:
+
+``` text
+┌─bitTest(43, 1)─┐
+│              1 │
+└────────────────┘
+```
+
+Another example:
+
+Query:
+
+``` sql
+SELECT bitTest(43, 2);
+```
+
+Result:
+
+``` text
+┌─bitTest(43, 2)─┐
+│              0 │
+└────────────────┘
+```
+
+## bitTestAll {#bittestall}
+
+Returns result of [logical conjuction](https://en.wikipedia.org/wiki/Logical_conjunction) (AND operator) of all bits at given positions. The countdown starts from 0 from the right to the left.
+
+The conjuction for bitwise operations:
+
+0 AND 0 = 0
+
+0 AND 1 = 0
+
+1 AND 0 = 0
+
+1 AND 1 = 1
+
+**Syntax**
+
+``` sql
+SELECT bitTestAll(number, index1, index2, index3, index4, ...)
+```
+
+**Arguments**
+
+-   `number` – Integer number.
+-   `index1`, `index2`, `index3`, `index4` – Positions of bit. For example, for set of positions (`index1`, `index2`, `index3`, `index4`) is true if and only if all of its positions are true (`index1` ⋀ `index2`, ⋀ `index3` ⋀ `index4`).
+
+**Returned values**
+
+Returns result of logical conjuction.
+
+Type: `UInt8`.
+
+**Example**
+
+For example, the number 43 in base-2 (binary) numeral system is 101011.
+
+Query:
+
+``` sql
+SELECT bitTestAll(43, 0, 1, 3, 5);
+```
+
+Result:
+
+``` text
+┌─bitTestAll(43, 0, 1, 3, 5)─┐
+│                          1 │
+└────────────────────────────┘
+```
+
+Another example:
+
+Query:
+
+``` sql
+SELECT bitTestAll(43, 0, 1, 3, 5, 2);
+```
+
+Result:
+
+``` text
+┌─bitTestAll(43, 0, 1, 3, 5, 2)─┐
+│                             0 │
+└───────────────────────────────┘
+```
+
+## bitTestAny {#bittestany}
+
+Returns result of [logical disjunction](https://en.wikipedia.org/wiki/Logical_disjunction) (OR operator) of all bits at given positions. The countdown starts from 0 from the right to the left.
+
+The disjunction for bitwise operations:
+
+0 OR 0 = 0
+
+0 OR 1 = 1
+
+1 OR 0 = 1
+
+1 OR 1 = 1
+
+**Syntax**
+
+``` sql
+SELECT bitTestAny(number, index1, index2, index3, index4, ...)
+```
+
+**Arguments**
+
+-   `number` – Integer number.
+-   `index1`, `index2`, `index3`, `index4` – Positions of bit.
+
+**Returned values**
+
+Returns result of logical disjuction.
+
+Type: `UInt8`.
+
+**Example**
+
+For example, the number 43 in base-2 (binary) numeral system is 101011.
+
+Query:
+
+``` sql
+SELECT bitTestAny(43, 0, 2);
+```
+
+Result:
+
+``` text
+┌─bitTestAny(43, 0, 2)─┐
+│                    1 │
+└──────────────────────┘
+```
+
+Another example:
+
+Query:
+
+``` sql
+SELECT bitTestAny(43, 4, 2);
+```
+
+Result:
+
+``` text
+┌─bitTestAny(43, 4, 2)─┐
+│                    0 │
+└──────────────────────┘
+```
+
+## bitCount {#bitcount}
+
+Calculates the number of bits set to one in the binary representation of a number.
+
+**Syntax**
+
+``` sql
+bitCount(x)
+```
+
+**Arguments**
+
+-   `x` — [Integer](../../sql-reference/data-types/int-uint.md) or [floating-point](../../sql-reference/data-types/float.md) number. The function uses the value representation in memory. It allows supporting floating-point numbers.
+
+**Returned value**
+
+-   Number of bits set to one in the input number.
+
+The function does not convert input value to a larger type ([sign extension](https://en.wikipedia.org/wiki/Sign_extension)). So, for example, `bitCount(toUInt8(-1)) = 8`.
+
+Type: `UInt8`.
+
+**Example**
+
+Take for example the number 333. Its binary representation: 0000000101001101.
+
+Query:
+
+``` sql
+SELECT bitCount(333);
+```
+
+Result:
+
+``` text
+┌─bitCount(333)─┐
+│             5 │
+└───────────────┘
+```
+
+## bitHammingDistance {#bithammingdistance}
+
+Returns the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) between the bit representations of two integer values. Can be used with [SimHash](../../sql-reference/functions/hash-functions.md#ngramsimhash) functions for detection of semi-duplicate strings. The smaller is the distance, the more likely those strings are the same.
+
+**Syntax**
+
+``` sql
+bitHammingDistance(int1, int2)
+```
+
+**Arguments**
+
+-   `int1` — First integer value. [Int64](../../sql-reference/data-types/int-uint.md).
+-   `int2` — Second integer value. [Int64](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   The Hamming distance.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT bitHammingDistance(111, 121);
+```
+
+Result:
+
+``` text
+┌─bitHammingDistance(111, 121)─┐
+│                            3 │
+└──────────────────────────────┘
+```
+
+With [SimHash](../../sql-reference/functions/hash-functions.md#ngramsimhash):
+
+``` sql
+SELECT bitHammingDistance(ngramSimHash('cat ate rat'), ngramSimHash('rat ate cat'));
+```
+
+Result:
+
+``` text
+┌─bitHammingDistance(ngramSimHash('cat ate rat'), ngramSimHash('rat ate cat'))─┐
+│                                                                            5 │
+└──────────────────────────────────────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/bitmap-functions.md b/docs/en/reference/sql-reference/functions/bitmap-functions.md
new file mode 100644
index 00000000000..68d1fc88a31
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/bitmap-functions.md
@@ -0,0 +1,537 @@
+---
+sidebar_position: 49
+sidebar_label: Bitmap
+---
+
+# Bitmap Functions {#bitmap-functions}
+
+Bitmap functions work for two bitmaps Object value calculation, it is to return new bitmap or cardinality while using formula calculation, such as and, or, xor, and not, etc.
+
+There are 2 kinds of construction methods for Bitmap Object. One is to be constructed by aggregation function groupBitmap with -State, the other is to be constructed by Array Object. It is also to convert Bitmap Object to Array Object.
+
+RoaringBitmap is wrapped into a data structure while actual storage of Bitmap objects. When the cardinality is less than or equal to 32, it uses Set objet. When the cardinality is greater than 32, it uses RoaringBitmap object. That is why storage of low cardinality set is faster.
+
+For more information on RoaringBitmap, see: [CRoaring](https://github.com/RoaringBitmap/CRoaring).
+
+## bitmapBuild {#bitmap_functions-bitmapbuild}
+
+Build a bitmap from unsigned integer array.
+
+``` sql
+bitmapBuild(array)
+```
+
+**Arguments**
+
+-   `array` – Unsigned integer array.
+
+**Example**
+
+``` sql
+SELECT bitmapBuild([1, 2, 3, 4, 5]) AS res, toTypeName(res);
+```
+
+``` text
+┌─res─┬─toTypeName(bitmapBuild([1, 2, 3, 4, 5]))─────┐
+│     │ AggregateFunction(groupBitmap, UInt8)        │
+└─────┴──────────────────────────────────────────────┘
+```
+
+## bitmapToArray {#bitmaptoarray}
+
+Convert bitmap to integer array.
+
+``` sql
+bitmapToArray(bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapToArray(bitmapBuild([1, 2, 3, 4, 5])) AS res;
+```
+
+``` text
+┌─res─────────┐
+│ [1,2,3,4,5] │
+└─────────────┘
+```
+
+## bitmapSubsetInRange {#bitmap-functions-bitmapsubsetinrange}
+
+Return subset in specified range (not include the range_end).
+
+``` sql
+bitmapSubsetInRange(bitmap, range_start, range_end)
+```
+
+**Arguments**
+
+-   `bitmap` – [Bitmap object](#bitmap_functions-bitmapbuild).
+-   `range_start` – Range start point. Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+-   `range_end` – Range end point (excluded). Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+``` sql
+SELECT bitmapToArray(bitmapSubsetInRange(bitmapBuild([0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,100,200,500]), toUInt32(30), toUInt32(200))) AS res;
+```
+
+``` text
+┌─res───────────────┐
+│ [30,31,32,33,100] │
+└───────────────────┘
+```
+
+## bitmapSubsetLimit {#bitmapsubsetlimit}
+
+Creates a subset of bitmap with n elements taken between `range_start` and `cardinality_limit`.
+
+**Syntax**
+
+``` sql
+bitmapSubsetLimit(bitmap, range_start, cardinality_limit)
+```
+
+**Arguments**
+
+-   `bitmap` – [Bitmap object](#bitmap_functions-bitmapbuild).
+-   `range_start` – The subset starting point. Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+-   `cardinality_limit` – The subset cardinality upper limit. Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+The subset.
+
+Type: [Bitmap object](#bitmap_functions-bitmapbuild).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT bitmapToArray(bitmapSubsetLimit(bitmapBuild([0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,100,200,500]), toUInt32(30), toUInt32(200))) AS res;
+```
+
+Result:
+
+``` text
+┌─res───────────────────────┐
+│ [30,31,32,33,100,200,500] │
+└───────────────────────────┘
+```
+
+## subBitmap {#subbitmap}
+
+Returns the bitmap elements, starting from the `offset` position. The number of returned elements is limited by the `cardinality_limit` parameter. Analog of the [substring](string-functions.md#substring)) string function, but for bitmap.
+
+**Syntax**
+
+``` sql
+subBitmap(bitmap, offset, cardinality_limit)
+```
+
+**Arguments**
+
+-   `bitmap` – The bitmap. Type: [Bitmap object](#bitmap_functions-bitmapbuild).
+-   `offset` – The position of the first element of the subset. Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+-   `cardinality_limit` – The maximum number of elements in the subset. Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+The subset.
+
+Type: [Bitmap object](#bitmap_functions-bitmapbuild).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT bitmapToArray(subBitmap(bitmapBuild([0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,100,200,500]), toUInt32(10), toUInt32(10))) AS res;
+```
+
+Result:
+
+``` text
+┌─res─────────────────────────────┐
+│ [10,11,12,13,14,15,16,17,18,19] │
+└─────────────────────────────────┘
+```
+
+## bitmapContains {#bitmap_functions-bitmapcontains}
+
+Checks whether the bitmap contains an element.
+
+``` sql
+bitmapContains(haystack, needle)
+```
+
+**Arguments**
+
+-   `haystack` – [Bitmap object](#bitmap_functions-bitmapbuild), where the function searches.
+-   `needle` – Value that the function searches. Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   0 — If `haystack` does not contain `needle`.
+-   1 — If `haystack` contains `needle`.
+
+Type: `UInt8`.
+
+**Example**
+
+``` sql
+SELECT bitmapContains(bitmapBuild([1,5,7,9]), toUInt32(9)) AS res;
+```
+
+``` text
+┌─res─┐
+│  1  │
+└─────┘
+```
+
+## bitmapHasAny {#bitmaphasany}
+
+Checks whether two bitmaps have intersection by some elements.
+
+``` sql
+bitmapHasAny(bitmap1, bitmap2)
+```
+
+If you are sure that `bitmap2` contains strictly one element, consider using the [bitmapContains](#bitmap_functions-bitmapcontains) function. It works more efficiently.
+
+**Arguments**
+
+-   `bitmap*` – Bitmap object.
+
+**Return values**
+
+-   `1`, if `bitmap1` and `bitmap2` have one similar element at least.
+-   `0`, otherwise.
+
+**Example**
+
+``` sql
+SELECT bitmapHasAny(bitmapBuild([1,2,3]),bitmapBuild([3,4,5])) AS res;
+```
+
+``` text
+┌─res─┐
+│  1  │
+└─────┘
+```
+
+## bitmapHasAll {#bitmaphasall}
+
+Analogous to `hasAll(array, array)` returns 1 if the first bitmap contains all the elements of the second one, 0 otherwise.
+If the second argument is an empty bitmap then returns 1.
+
+``` sql
+bitmapHasAll(bitmap,bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapHasAll(bitmapBuild([1,2,3]),bitmapBuild([3,4,5])) AS res;
+```
+
+``` text
+┌─res─┐
+│  0  │
+└─────┘
+```
+
+## bitmapCardinality {#bitmapcardinality}
+
+Retrun bitmap cardinality of type UInt64.
+
+``` sql
+bitmapCardinality(bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapCardinality(bitmapBuild([1, 2, 3, 4, 5])) AS res;
+```
+
+``` text
+┌─res─┐
+│   5 │
+└─────┘
+```
+
+## bitmapMin {#bitmapmin}
+
+Retrun the smallest value of type UInt64 in the set, UINT32_MAX if the set is empty.
+
+    bitmapMin(bitmap)
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapMin(bitmapBuild([1, 2, 3, 4, 5])) AS res;
+```
+
+``` text
+ ┌─res─┐
+ │   1 │
+ └─────┘
+```
+
+## bitmapMax {#bitmapmax}
+
+Retrun the greatest value of type UInt64 in the set, 0 if the set is empty.
+
+    bitmapMax(bitmap)
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapMax(bitmapBuild([1, 2, 3, 4, 5])) AS res;
+```
+
+``` text
+ ┌─res─┐
+ │   5 │
+ └─────┘
+```
+
+## bitmapTransform {#bitmaptransform}
+
+Transform an array of values in a bitmap to another array of values, the result is a new bitmap.
+
+    bitmapTransform(bitmap, from_array, to_array)
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+-   `from_array` – UInt32 array. For idx in range \[0, from_array.size()), if bitmap contains from_array\[idx\], then replace it with to_array\[idx\]. Note that the result depends on array ordering if there are common elements between from_array and to_array.
+-   `to_array` – UInt32 array, its size shall be the same to from_array.
+
+**Example**
+
+``` sql
+SELECT bitmapToArray(bitmapTransform(bitmapBuild([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]), cast([5,999,2] as Array(UInt32)), cast([2,888,20] as Array(UInt32)))) AS res;
+```
+
+``` text
+ ┌─res───────────────────┐
+ │ [1,3,4,6,7,8,9,10,20] │
+ └───────────────────────┘
+```
+
+## bitmapAnd {#bitmapand}
+
+Two bitmap and calculation, the result is a new bitmap.
+
+``` sql
+bitmapAnd(bitmap,bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapToArray(bitmapAnd(bitmapBuild([1,2,3]),bitmapBuild([3,4,5]))) AS res;
+```
+
+``` text
+┌─res─┐
+│ [3] │
+└─────┘
+```
+
+## bitmapOr {#bitmapor}
+
+Two bitmap or calculation, the result is a new bitmap.
+
+``` sql
+bitmapOr(bitmap,bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapToArray(bitmapOr(bitmapBuild([1,2,3]),bitmapBuild([3,4,5]))) AS res;
+```
+
+``` text
+┌─res─────────┐
+│ [1,2,3,4,5] │
+└─────────────┘
+```
+
+## bitmapXor {#bitmapxor}
+
+Two bitmap xor calculation, the result is a new bitmap.
+
+``` sql
+bitmapXor(bitmap,bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapToArray(bitmapXor(bitmapBuild([1,2,3]),bitmapBuild([3,4,5]))) AS res;
+```
+
+``` text
+┌─res───────┐
+│ [1,2,4,5] │
+└───────────┘
+```
+
+## bitmapAndnot {#bitmapandnot}
+
+Two bitmap andnot calculation, the result is a new bitmap.
+
+``` sql
+bitmapAndnot(bitmap,bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapToArray(bitmapAndnot(bitmapBuild([1,2,3]),bitmapBuild([3,4,5]))) AS res;
+```
+
+``` text
+┌─res───┐
+│ [1,2] │
+└───────┘
+```
+
+## bitmapAndCardinality {#bitmapandcardinality}
+
+Two bitmap and calculation, return cardinality of type UInt64.
+
+``` sql
+bitmapAndCardinality(bitmap,bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapAndCardinality(bitmapBuild([1,2,3]),bitmapBuild([3,4,5])) AS res;
+```
+
+``` text
+┌─res─┐
+│   1 │
+└─────┘
+```
+
+## bitmapOrCardinality {#bitmaporcardinality}
+
+Two bitmap or calculation, return cardinality of type UInt64.
+
+``` sql
+bitmapOrCardinality(bitmap,bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapOrCardinality(bitmapBuild([1,2,3]),bitmapBuild([3,4,5])) AS res;
+```
+
+``` text
+┌─res─┐
+│   5 │
+└─────┘
+```
+
+## bitmapXorCardinality {#bitmapxorcardinality}
+
+Two bitmap xor calculation, return cardinality of type UInt64.
+
+``` sql
+bitmapXorCardinality(bitmap,bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapXorCardinality(bitmapBuild([1,2,3]),bitmapBuild([3,4,5])) AS res;
+```
+
+``` text
+┌─res─┐
+│   4 │
+└─────┘
+```
+
+## bitmapAndnotCardinality {#bitmapandnotcardinality}
+
+Two bitmap andnot calculation, return cardinality of type UInt64.
+
+``` sql
+bitmapAndnotCardinality(bitmap,bitmap)
+```
+
+**Arguments**
+
+-   `bitmap` – Bitmap object.
+
+**Example**
+
+``` sql
+SELECT bitmapAndnotCardinality(bitmapBuild([1,2,3]),bitmapBuild([3,4,5])) AS res;
+```
+
+``` text
+┌─res─┐
+│   2 │
+└─────┘
+```
+
diff --git a/docs/en/reference/sql-reference/functions/comparison-functions.md b/docs/en/reference/sql-reference/functions/comparison-functions.md
new file mode 100644
index 00000000000..b5e842ddcad
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/comparison-functions.md
@@ -0,0 +1,34 @@
+---
+sidebar_position: 36
+sidebar_label: Comparison
+---
+
+# Comparison Functions {#comparison-functions}
+
+Comparison functions always return 0 or 1 (Uint8).
+
+The following types can be compared:
+
+-   numbers
+-   strings and fixed strings
+-   dates
+-   dates with times
+
+within each group, but not between different groups.
+
+For example, you can’t compare a date with a string. You have to use a function to convert the string to a date, or vice versa.
+
+Strings are compared by bytes. A shorter string is smaller than all strings that start with it and that contain at least one more character.
+
+## equals, a = b and a == b operator {#function-equals}
+
+## notEquals, a != b and a \<\> b operator {#function-notequals}
+
+## less, \< operator {#function-less}
+
+## greater, \> operator {#function-greater}
+
+## lessOrEquals, \<= operator {#function-lessorequals}
+
+## greaterOrEquals, \>= operator {#function-greaterorequals}
+
diff --git a/docs/en/reference/sql-reference/functions/conditional-functions.md b/docs/en/reference/sql-reference/functions/conditional-functions.md
new file mode 100644
index 00000000000..21189bbb072
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/conditional-functions.md
@@ -0,0 +1,211 @@
+---
+sidebar_position: 43
+sidebar_label: 'Conditional '
+---
+
+# Conditional Functions {#conditional-functions}
+
+## if {#if}
+
+Controls conditional branching. Unlike most systems, ClickHouse always evaluate both expressions `then` and `else`.
+
+**Syntax**
+
+``` sql
+if(cond, then, else)
+```
+
+If the condition `cond` evaluates to a non-zero value, returns the result of the expression `then`, and the result of the expression `else`, if present, is skipped. If the `cond` is zero or `NULL`, then the result of the `then` expression is skipped and the result of the `else` expression, if present, is returned.
+
+You can use the [short_circuit_function_evaluation](../../operations/settings/settings.md#short-circuit-function-evaluation) setting to calculate the `if` function according to a short scheme. If this setting is enabled, `then` expression is evaluated only on rows where `cond` is true, `else` expression – where `cond` is false. For example, an exception about division by zero is not thrown when executing the query `SELECT if(number = 0, 0, intDiv(42, number)) FROM numbers(10)`, because `intDiv(42, number)` will be evaluated only for numbers that doesn't satisfy condition `number = 0`.
+
+**Arguments**
+
+-   `cond` – The condition for evaluation that can be zero or not. The type is UInt8, Nullable(UInt8) or NULL.
+-   `then` – The expression to return if condition is met.
+-   `else` – The expression to return if condition is not met.
+
+**Returned values**
+
+The function executes `then` and `else` expressions and returns its result, depending on whether the condition `cond` ended up being zero or not.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT if(1, plus(2, 2), plus(2, 6));
+```
+
+Result:
+
+``` text
+┌─plus(2, 2)─┐
+│          4 │
+└────────────┘
+```
+
+Query:
+
+``` sql
+SELECT if(0, plus(2, 2), plus(2, 6));
+```
+
+Result:
+
+``` text
+┌─plus(2, 6)─┐
+│          8 │
+└────────────┘
+```
+
+-   `then` and `else` must have the lowest common type.
+
+**Example:**
+
+Take this `LEFT_RIGHT` table:
+
+``` sql
+SELECT *
+FROM LEFT_RIGHT
+
+┌─left─┬─right─┐
+│ ᴺᵁᴸᴸ │     4 │
+│    1 │     3 │
+│    2 │     2 │
+│    3 │     1 │
+│    4 │  ᴺᵁᴸᴸ │
+└──────┴───────┘
+```
+
+The following query compares `left` and `right` values:
+
+``` sql
+SELECT
+    left,
+    right,
+    if(left < right, 'left is smaller than right', 'right is greater or equal than left') AS is_smaller
+FROM LEFT_RIGHT
+WHERE isNotNull(left) AND isNotNull(right)
+
+┌─left─┬─right─┬─is_smaller──────────────────────────┐
+│    1 │     3 │ left is smaller than right          │
+│    2 │     2 │ right is greater or equal than left │
+│    3 │     1 │ right is greater or equal than left │
+└──────┴───────┴─────────────────────────────────────┘
+```
+
+Note: `NULL` values are not used in this example, check [NULL values in conditionals](#null-values-in-conditionals) section.
+
+## Ternary Operator {#ternary-operator}
+
+It works same as `if` function.
+
+Syntax: `cond ? then : else`
+
+Returns `then` if the `cond` evaluates to be true (greater than zero), otherwise returns `else`.
+
+-   `cond` must be of type of `UInt8`, and `then` and `else` must have the lowest common type.
+
+-   `then` and `else` can be `NULL`
+
+**See also**
+
+-   [ifNotFinite](../../sql-reference/functions/other-functions.md#ifnotfinite).
+
+## multiIf {#multiif}
+
+Allows you to write the [CASE](../../sql-reference/operators/index.md#operator_case) operator more compactly in the query.
+
+**Syntax**
+
+``` sql
+multiIf(cond_1, then_1, cond_2, then_2, ..., else)
+```
+
+You can use the [short_circuit_function_evaluation](../../operations/settings/settings.md#short-circuit-function-evaluation) setting to calculate the `multiIf` function according to a short scheme. If this setting is enabled, `then_i` expression is evaluated only on rows where `((NOT cond_1) AND (NOT cond_2) AND ... AND (NOT cond_{i-1}) AND cond_i)` is true, `cond_i` will be evaluated only on rows where `((NOT cond_1) AND (NOT cond_2) AND ... AND (NOT cond_{i-1}))` is true. For example, an exception about division by zero is not thrown when executing the query `SELECT multiIf(number = 2, intDiv(1, number), number = 5) FROM numbers(10)`.
+
+**Arguments**
+
+-   `cond_N` — The condition for the function to return `then_N`.
+-   `then_N` — The result of the function when executed.
+-   `else` — The result of the function if none of the conditions is met.
+
+The function accepts `2N+1` parameters.
+
+**Returned values**
+
+The function returns one of the values `then_N` or `else`, depending on the conditions `cond_N`.
+
+**Example**
+
+Again using `LEFT_RIGHT` table.
+
+``` sql
+SELECT
+    left,
+    right,
+    multiIf(left < right, 'left is smaller', left > right, 'left is greater', left = right, 'Both equal', 'Null value') AS result
+FROM LEFT_RIGHT
+
+┌─left─┬─right─┬─result──────────┐
+│ ᴺᵁᴸᴸ │     4 │ Null value      │
+│    1 │     3 │ left is smaller │
+│    2 │     2 │ Both equal      │
+│    3 │     1 │ left is greater │
+│    4 │  ᴺᵁᴸᴸ │ Null value      │
+└──────┴───────┴─────────────────┘
+```
+
+## Using Conditional Results Directly {#using-conditional-results-directly}
+
+Conditionals always result to `0`, `1` or `NULL`. So you can use conditional results directly like this:
+
+``` sql
+SELECT left < right AS is_small
+FROM LEFT_RIGHT
+
+┌─is_small─┐
+│     ᴺᵁᴸᴸ │
+│        1 │
+│        0 │
+│        0 │
+│     ᴺᵁᴸᴸ │
+└──────────┘
+```
+
+## NULL Values in Conditionals {#null-values-in-conditionals}
+
+When `NULL` values are involved in conditionals, the result will also be `NULL`.
+
+``` sql
+SELECT
+    NULL < 1,
+    2 < NULL,
+    NULL < NULL,
+    NULL = NULL
+
+┌─less(NULL, 1)─┬─less(2, NULL)─┬─less(NULL, NULL)─┬─equals(NULL, NULL)─┐
+│ ᴺᵁᴸᴸ          │ ᴺᵁᴸᴸ          │ ᴺᵁᴸᴸ             │ ᴺᵁᴸᴸ               │
+└───────────────┴───────────────┴──────────────────┴────────────────────┘
+```
+
+So you should construct your queries carefully if the types are `Nullable`.
+
+The following example demonstrates this by failing to add equals condition to `multiIf`.
+
+``` sql
+SELECT
+    left,
+    right,
+    multiIf(left < right, 'left is smaller', left > right, 'right is smaller', 'Both equal') AS faulty_result
+FROM LEFT_RIGHT
+
+┌─left─┬─right─┬─faulty_result────┐
+│ ᴺᵁᴸᴸ │     4 │ Both equal       │
+│    1 │     3 │ left is smaller  │
+│    2 │     2 │ Both equal       │
+│    3 │     1 │ right is smaller │
+│    4 │  ᴺᵁᴸᴸ │ Both equal       │
+└──────┴───────┴──────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/date-time-functions.md b/docs/en/reference/sql-reference/functions/date-time-functions.md
new file mode 100644
index 00000000000..5f783cf4149
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/date-time-functions.md
@@ -0,0 +1,1233 @@
+---
+sidebar_position: 39
+sidebar_label: Dates and Times
+---
+
+# Functions for Working with Dates and Times {#functions-for-working-with-dates-and-times}
+
+Support for time zones.
+
+All functions for working with the date and time that have a logical use for the time zone can accept a second optional time zone argument. Example: Asia/Yekaterinburg. In this case, they use the specified time zone instead of the local (default) one.
+
+``` sql
+SELECT
+    toDateTime('2016-06-15 23:00:00') AS time,
+    toDate(time) AS date_local,
+    toDate(time, 'Asia/Yekaterinburg') AS date_yekat,
+    toString(time, 'US/Samoa') AS time_samoa
+```
+
+``` text
+┌────────────────time─┬─date_local─┬─date_yekat─┬─time_samoa──────────┐
+│ 2016-06-15 23:00:00 │ 2016-06-15 │ 2016-06-16 │ 2016-06-15 09:00:00 │
+└─────────────────────┴────────────┴────────────┴─────────────────────┘
+```
+
+## timeZone {#timezone}
+
+Returns the timezone of the server.
+If it is executed in the context of a distributed table, then it generates a normal column with values relevant to each shard. Otherwise it produces a constant value.
+
+**Syntax**
+
+``` sql
+timeZone()
+```
+
+Alias: `timezone`.
+
+**Returned value**
+
+-   Timezone.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+## toTimeZone {#totimezone}
+
+Converts time or date and time to the specified time zone. The time zone is an attribute of the `Date` and `DateTime` data types. The internal value (number of seconds) of the table field or of the resultset's column does not change, the column's type changes and its string representation changes accordingly.
+
+**Syntax**
+
+``` sql
+toTimezone(value, timezone)
+```
+
+Alias: `toTimezone`.
+
+**Arguments**
+
+-   `value` — Time or date and time. [DateTime64](../../sql-reference/data-types/datetime64.md).
+-   `timezone` — Timezone for the returned value. [String](../../sql-reference/data-types/string.md). This argument is a constant, because `toTimezone` changes the timezone of a column (timezone is an attribute of `DateTime*` types).
+
+**Returned value**
+
+-   Date and time.
+
+Type: [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT toDateTime('2019-01-01 00:00:00', 'UTC') AS time_utc,
+    toTypeName(time_utc) AS type_utc,
+    toInt32(time_utc) AS int32utc,
+    toTimeZone(time_utc, 'Asia/Yekaterinburg') AS time_yekat,
+    toTypeName(time_yekat) AS type_yekat,
+    toInt32(time_yekat) AS int32yekat,
+    toTimeZone(time_utc, 'US/Samoa') AS time_samoa,
+    toTypeName(time_samoa) AS type_samoa,
+    toInt32(time_samoa) AS int32samoa
+FORMAT Vertical;
+```
+
+Result:
+
+```text
+Row 1:
+──────
+time_utc:   2019-01-01 00:00:00
+type_utc:   DateTime('UTC')
+int32utc:   1546300800
+time_yekat: 2019-01-01 05:00:00
+type_yekat: DateTime('Asia/Yekaterinburg')
+int32yekat: 1546300800
+time_samoa: 2018-12-31 13:00:00
+type_samoa: DateTime('US/Samoa')
+int32samoa: 1546300800
+```
+
+`toTimeZone(time_utc, 'Asia/Yekaterinburg')` changes the `DateTime('UTC')` type to `DateTime('Asia/Yekaterinburg')`. The value (Unixtimestamp) 1546300800 stays the same, but the string representation (the result of the toString() function) changes from `time_utc:   2019-01-01 00:00:00` to `time_yekat: 2019-01-01 05:00:00`.
+
+## timeZoneOf {#timezoneof}
+
+Returns the timezone name of [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md) data types.
+
+**Syntax**
+
+``` sql
+timeZoneOf(value)
+```
+
+Alias: `timezoneOf`.
+
+**Arguments**
+
+-   `value` — Date and time. [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
+
+**Returned value**
+
+-   Timezone name.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+``` sql
+SELECT timezoneOf(now());
+```
+
+Result:
+``` text
+┌─timezoneOf(now())─┐
+│ Etc/UTC           │
+└───────────────────┘
+```
+
+## timeZoneOffset {#timezoneoffset}
+
+Returns a timezone offset in seconds from [UTC](https://en.wikipedia.org/wiki/Coordinated_Universal_Time). The function takes into account [daylight saving time](https://en.wikipedia.org/wiki/Daylight_saving_time) and historical timezone changes at the specified date and time.
+[IANA timezone database](https://www.iana.org/time-zones) is used to calculate the offset.
+
+**Syntax**
+
+``` sql
+timeZoneOffset(value)
+```
+
+Alias: `timezoneOffset`.
+
+**Arguments**
+
+-   `value` — Date and time. [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
+
+**Returned value**
+
+-   Offset from UTC in seconds.
+
+Type: [Int32](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toDateTime('2021-04-21 10:20:30', 'America/New_York') AS Time, toTypeName(Time) AS Type,
+       timeZoneOffset(Time) AS Offset_in_seconds, (Offset_in_seconds / 3600) AS Offset_in_hours;
+```
+
+Result:
+
+``` text
+┌────────────────Time─┬─Type─────────────────────────┬─Offset_in_seconds─┬─Offset_in_hours─┐
+│ 2021-04-21 10:20:30 │ DateTime('America/New_York') │            -14400 │              -4 │
+└─────────────────────┴──────────────────────────────┴───────────────────┴─────────────────┘
+```
+
+## toYear {#toyear}
+
+Converts a date or date with time to a UInt16 number containing the year number (AD).
+
+Alias: `YEAR`.
+
+## toQuarter {#toquarter}
+
+Converts a date or date with time to a UInt8 number containing the quarter number.
+
+Alias: `QUARTER`.
+
+## toMonth {#tomonth}
+
+Converts a date or date with time to a UInt8 number containing the month number (1-12).
+
+Alias: `MONTH`.
+
+## toDayOfYear {#todayofyear}
+
+Converts a date or date with time to a UInt16 number containing the number of the day of the year (1-366).
+
+Alias: `DAYOFYEAR`.
+
+## toDayOfMonth {#todayofmonth}
+
+Converts a date or date with time to a UInt8 number containing the number of the day of the month (1-31).
+
+Aliases: `DAYOFMONTH`, `DAY`.
+
+## toDayOfWeek {#todayofweek}
+
+Converts a date or date with time to a UInt8 number containing the number of the day of the week (Monday is 1, and Sunday is 7).
+
+Alias: `DAYOFWEEK`.
+
+## toHour {#tohour}
+
+Converts a date with time to a UInt8 number containing the number of the hour in 24-hour time (0-23).
+This function assumes that if clocks are moved ahead, it is by one hour and occurs at 2 a.m., and if clocks are moved back, it is by one hour and occurs at 3 a.m. (which is not always true – even in Moscow the clocks were twice changed at a different time).
+
+Alias: `HOUR`.
+
+## toMinute {#tominute}
+
+Converts a date with time to a UInt8 number containing the number of the minute of the hour (0-59).
+
+Alias: `MINUTE`.
+
+## toSecond {#tosecond}
+
+Converts a date with time to a UInt8 number containing the number of the second in the minute (0-59).
+Leap seconds are not accounted for.
+
+Alias: `SECOND`.
+
+## toUnixTimestamp {#to-unix-timestamp}
+
+For DateTime argument: converts value to the number with type UInt32 -- Unix Timestamp (https://en.wikipedia.org/wiki/Unix_time).
+For String argument: converts the input string to the datetime according to the timezone (optional second argument, server timezone is used by default) and returns the corresponding unix timestamp.
+
+**Syntax**
+
+``` sql
+toUnixTimestamp(datetime)
+toUnixTimestamp(str, [timezone])
+```
+
+**Returned value**
+
+-   Returns the unix timestamp.
+
+Type: `UInt32`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toUnixTimestamp('2017-11-05 08:07:47', 'Asia/Tokyo') AS unix_timestamp
+```
+
+Result:
+
+``` text
+┌─unix_timestamp─┐
+│     1509836867 │
+└────────────────┘
+```
+
+:::note    
+The return type `toStartOf*` functions described below is `Date` or `DateTime`. Though these functions can take `DateTime64` as an argument, passing them a `DateTime64` that is out of the normal range (years 1925 - 2283) will give an incorrect result.
+:::
+
+## toStartOfYear {#tostartofyear}
+
+Rounds down a date or date with time to the first day of the year.
+Returns the date.
+
+## toStartOfISOYear {#tostartofisoyear}
+
+Rounds down a date or date with time to the first day of ISO year.
+Returns the date.
+
+## toStartOfQuarter {#tostartofquarter}
+
+Rounds down a date or date with time to the first day of the quarter.
+The first day of the quarter is either 1 January, 1 April, 1 July, or 1 October.
+Returns the date.
+
+## toStartOfMonth {#tostartofmonth}
+
+Rounds down a date or date with time to the first day of the month.
+Returns the date.
+
+:::note    
+The behavior of parsing incorrect dates is implementation specific. ClickHouse may return zero date, throw an exception or do “natural” overflow.
+:::
+
+## toMonday {#tomonday}
+
+Rounds down a date or date with time to the nearest Monday.
+Returns the date.
+
+## toStartOfWeek(t\[,mode\]) {#tostartofweektmode}
+
+Rounds down a date or date with time to the nearest Sunday or Monday by mode.
+Returns the date.
+The mode argument works exactly like the mode argument to toWeek(). For the single-argument syntax, a mode value of 0 is used.
+
+## toStartOfDay {#tostartofday}
+
+Rounds down a date with time to the start of the day.
+
+## toStartOfHour {#tostartofhour}
+
+Rounds down a date with time to the start of the hour.
+
+## toStartOfMinute {#tostartofminute}
+
+Rounds down a date with time to the start of the minute.
+
+## toStartOfSecond {#tostartofsecond}
+
+Truncates sub-seconds.
+
+**Syntax**
+
+``` sql
+toStartOfSecond(value, [timezone])
+```
+
+**Arguments**
+
+-   `value` — Date and time. [DateTime64](../../sql-reference/data-types/datetime64.md).
+-   `timezone` — [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional). If not specified, the function uses the timezone of the `value` parameter. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Input value without sub-seconds.
+
+Type: [DateTime64](../../sql-reference/data-types/datetime64.md).
+
+**Examples**
+
+Query without timezone:
+
+``` sql
+WITH toDateTime64('2020-01-01 10:20:30.999', 3) AS dt64
+SELECT toStartOfSecond(dt64);
+```
+
+Result:
+
+``` text
+┌───toStartOfSecond(dt64)─┐
+│ 2020-01-01 10:20:30.000 │
+└─────────────────────────┘
+```
+
+Query with timezone:
+
+``` sql
+WITH toDateTime64('2020-01-01 10:20:30.999', 3) AS dt64
+SELECT toStartOfSecond(dt64, 'Asia/Istanbul');
+```
+
+Result:
+
+``` text
+┌─toStartOfSecond(dt64, 'Asia/Istanbul')─┐
+│                2020-01-01 13:20:30.000 │
+└────────────────────────────────────────┘
+```
+
+**See also**
+
+-   [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) server configuration parameter.
+
+## toStartOfFiveMinute {#tostartoffiveminute}
+
+Rounds down a date with time to the start of the five-minute interval.
+
+## toStartOfTenMinutes {#tostartoftenminutes}
+
+Rounds down a date with time to the start of the ten-minute interval.
+
+## toStartOfFifteenMinutes {#tostartoffifteenminutes}
+
+Rounds down the date with time to the start of the fifteen-minute interval.
+
+## toStartOfInterval(time_or_data, INTERVAL x unit \[, time_zone\]) {#tostartofintervaltime-or-data-interval-x-unit-time-zone}
+
+This is a generalization of other functions named `toStartOf*`. For example,
+`toStartOfInterval(t, INTERVAL 1 year)` returns the same as `toStartOfYear(t)`,
+`toStartOfInterval(t, INTERVAL 1 month)` returns the same as `toStartOfMonth(t)`,
+`toStartOfInterval(t, INTERVAL 1 day)` returns the same as `toStartOfDay(t)`,
+`toStartOfInterval(t, INTERVAL 15 minute)` returns the same as `toStartOfFifteenMinutes(t)` etc.
+
+## toTime {#totime}
+
+Converts a date with time to a certain fixed date, while preserving the time.
+
+## toRelativeYearNum {#torelativeyearnum}
+
+Converts a date with time or date to the number of the year, starting from a certain fixed point in the past.
+
+## toRelativeQuarterNum {#torelativequarternum}
+
+Converts a date with time or date to the number of the quarter, starting from a certain fixed point in the past.
+
+## toRelativeMonthNum {#torelativemonthnum}
+
+Converts a date with time or date to the number of the month, starting from a certain fixed point in the past.
+
+## toRelativeWeekNum {#torelativeweeknum}
+
+Converts a date with time or date to the number of the week, starting from a certain fixed point in the past.
+
+## toRelativeDayNum {#torelativedaynum}
+
+Converts a date with time or date to the number of the day, starting from a certain fixed point in the past.
+
+## toRelativeHourNum {#torelativehournum}
+
+Converts a date with time or date to the number of the hour, starting from a certain fixed point in the past.
+
+## toRelativeMinuteNum {#torelativeminutenum}
+
+Converts a date with time or date to the number of the minute, starting from a certain fixed point in the past.
+
+## toRelativeSecondNum {#torelativesecondnum}
+
+Converts a date with time or date to the number of the second, starting from a certain fixed point in the past.
+
+## toISOYear {#toisoyear}
+
+Converts a date or date with time to a UInt16 number containing the ISO Year number.
+
+## toISOWeek {#toisoweek}
+
+Converts a date or date with time to a UInt8 number containing the ISO Week number.
+
+## toWeek(date\[,mode\]) {#toweekdatemode}
+
+This function returns the week number for date or datetime. The two-argument form of toWeek() enables you to specify whether the week starts on Sunday or Monday and whether the return value should be in the range from 0 to 53 or from 1 to 53. If the mode argument is omitted, the default mode is 0.
+`toISOWeek()`is a compatibility function that is equivalent to `toWeek(date,3)`.
+The following table describes how the mode argument works.
+
+| Mode | First day of week | Range | Week 1 is the first week …    |
+|------|-------------------|-------|-------------------------------|
+| 0    | Sunday            | 0-53  | with a Sunday in this year    |
+| 1    | Monday            | 0-53  | with 4 or more days this year |
+| 2    | Sunday            | 1-53  | with a Sunday in this year    |
+| 3    | Monday            | 1-53  | with 4 or more days this year |
+| 4    | Sunday            | 0-53  | with 4 or more days this year |
+| 5    | Monday            | 0-53  | with a Monday in this year    |
+| 6    | Sunday            | 1-53  | with 4 or more days this year |
+| 7    | Monday            | 1-53  | with a Monday in this year    |
+| 8    | Sunday            | 1-53  | contains January 1            |
+| 9    | Monday            | 1-53  | contains January 1            |
+
+For mode values with a meaning of “with 4 or more days this year,” weeks are numbered according to ISO 8601:1988:
+
+-   If the week containing January 1 has 4 or more days in the new year, it is week 1.
+
+-   Otherwise, it is the last week of the previous year, and the next week is week 1.
+
+For mode values with a meaning of “contains January 1”, the week contains January 1 is week 1. It does not matter how many days in the new year the week contained, even if it contained only one day.
+
+``` sql
+toWeek(date, [, mode][, Timezone])
+```
+
+**Arguments**
+
+-   `date` – Date or DateTime.
+-   `mode` – Optional parameter, Range of values is \[0,9\], default is 0.
+-   `Timezone` – Optional parameter, it behaves like any other conversion function.
+
+**Example**
+
+``` sql
+SELECT toDate('2016-12-27') AS date, toWeek(date) AS week0, toWeek(date,1) AS week1, toWeek(date,9) AS week9;
+```
+
+``` text
+┌───────date─┬─week0─┬─week1─┬─week9─┐
+│ 2016-12-27 │    52 │    52 │     1 │
+└────────────┴───────┴───────┴───────┘
+```
+
+## toYearWeek(date\[,mode\]) {#toyearweekdatemode}
+
+Returns year and week for a date. The year in the result may be different from the year in the date argument for the first and the last week of the year.
+
+The mode argument works exactly like the mode argument to toWeek(). For the single-argument syntax, a mode value of 0 is used.
+
+`toISOYear()`is a compatibility function that is equivalent to `intDiv(toYearWeek(date,3),100)`.
+
+**Example**
+
+``` sql
+SELECT toDate('2016-12-27') AS date, toYearWeek(date) AS yearWeek0, toYearWeek(date,1) AS yearWeek1, toYearWeek(date,9) AS yearWeek9;
+```
+
+``` text
+┌───────date─┬─yearWeek0─┬─yearWeek1─┬─yearWeek9─┐
+│ 2016-12-27 │    201652 │    201652 │    201701 │
+└────────────┴───────────┴───────────┴───────────┘
+```
+
+## date\_trunc {#date_trunc}
+
+Truncates date and time data to the specified part of date.
+
+**Syntax**
+
+``` sql
+date_trunc(unit, value[, timezone])
+```
+
+Alias: `dateTrunc`.
+
+**Arguments**
+
+-   `unit` — The type of interval to truncate the result. [String Literal](../syntax.md#syntax-string-literal).
+    Possible values:
+
+    - `second`
+    - `minute`
+    - `hour`
+    - `day`
+    - `week`
+    - `month`
+    - `quarter`
+    - `year`
+
+-   `value` — Date and time. [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
+-   `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional). If not specified, the function uses the timezone of the `value` parameter. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Value, truncated to the specified part of date.
+
+Type: [Datetime](../../sql-reference/data-types/datetime.md).
+
+**Example**
+
+Query without timezone:
+
+``` sql
+SELECT now(), date_trunc('hour', now());
+```
+
+Result:
+
+``` text
+┌───────────────now()─┬─date_trunc('hour', now())─┐
+│ 2020-09-28 10:40:45 │       2020-09-28 10:00:00 │
+└─────────────────────┴───────────────────────────┘
+```
+
+Query with the specified timezone:
+
+```sql
+SELECT now(), date_trunc('hour', now(), 'Asia/Istanbul');
+```
+
+Result:
+
+```text
+┌───────────────now()─┬─date_trunc('hour', now(), 'Asia/Istanbul')─┐
+│ 2020-09-28 10:46:26 │                        2020-09-28 13:00:00 │
+└─────────────────────┴────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [toStartOfInterval](#tostartofintervaltime-or-data-interval-x-unit-time-zone)
+
+## date\_add {#date_add}
+
+Adds the time interval or date interval to the provided date or date with time.
+
+**Syntax**
+
+``` sql
+date_add(unit, value, date)
+```
+
+Aliases: `dateAdd`, `DATE_ADD`.
+
+**Arguments**
+
+-   `unit` — The type of interval to add. [String](../../sql-reference/data-types/string.md).
+    Possible values:
+
+    - `second`
+    - `minute`
+    - `hour`
+    - `day`
+    - `week`
+    - `month`
+    - `quarter`
+    - `year`
+
+-   `value` — Value of interval to add. [Int](../../sql-reference/data-types/int-uint.md).
+-   `date` — The date or date with time to which `value` is added. [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+Date or date with time obtained by adding `value`, expressed in `unit`, to `date`.
+
+Type: [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT date_add(YEAR, 3, toDate('2018-01-01'));
+```
+
+Result:
+
+```text
+┌─plus(toDate('2018-01-01'), toIntervalYear(3))─┐
+│                                    2021-01-01 │
+└───────────────────────────────────────────────┘
+```
+
+## date\_diff {#date_diff}
+
+Returns the difference between two dates or dates with time values.
+
+**Syntax**
+
+``` sql
+date_diff('unit', startdate, enddate, [timezone])
+```
+
+Aliases: `dateDiff`, `DATE_DIFF`.
+
+**Arguments**
+
+-   `unit` — The type of interval for result. [String](../../sql-reference/data-types/string.md).
+    Possible values:
+
+    - `second`
+    - `minute`
+    - `hour`
+    - `day`
+    - `week`
+    - `month`
+    - `quarter`
+    - `year`
+
+-   `startdate` — The first time value to subtract (the subtrahend). [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+-   `enddate` — The second time value to subtract from (the minuend). [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+-   `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) (optional). If specified, it is applied to both `startdate` and `enddate`. If not specified, timezones of `startdate` and `enddate` are used. If they are not the same, the result is unspecified. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+Difference between `enddate` and `startdate` expressed in `unit`.
+
+Type: [Int](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT dateDiff('hour', toDateTime('2018-01-01 22:00:00'), toDateTime('2018-01-02 23:00:00'));
+```
+
+Result:
+
+``` text
+┌─dateDiff('hour', toDateTime('2018-01-01 22:00:00'), toDateTime('2018-01-02 23:00:00'))─┐
+│                                                                                     25 │
+└────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+## date\_sub {#date_sub}
+
+Subtracts the time interval or date interval from the provided date or date with time.
+
+**Syntax**
+
+``` sql
+date_sub(unit, value, date)
+```
+
+Aliases: `dateSub`, `DATE_SUB`.
+
+**Arguments**
+
+-   `unit` — The type of interval to subtract. [String](../../sql-reference/data-types/string.md).
+    Possible values:
+
+    - `second`
+    - `minute`
+    - `hour`
+    - `day`
+    - `week`
+    - `month`
+    - `quarter`
+    - `year`
+
+-   `value` — Value of interval to subtract. [Int](../../sql-reference/data-types/int-uint.md).
+-   `date` — The date or date with time from which `value` is subtracted. [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+Date or date with time obtained by subtracting `value`, expressed in `unit`, from `date`.
+
+Type: [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT date_sub(YEAR, 3, toDate('2018-01-01'));
+```
+
+Result:
+
+``` text
+┌─minus(toDate('2018-01-01'), toIntervalYear(3))─┐
+│                                     2015-01-01 │
+└────────────────────────────────────────────────┘
+```
+
+## timestamp\_add {#timestamp_add}
+
+Adds the specified time value with the provided date or date time value.
+
+**Syntax**
+
+``` sql
+timestamp_add(date, INTERVAL value unit)
+```
+
+Aliases: `timeStampAdd`, `TIMESTAMP_ADD`.
+
+**Arguments**
+
+-   `date` — Date or date with time. [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+-   `value` — Value of interval to add. [Int](../../sql-reference/data-types/int-uint.md).
+-   `unit` — The type of interval to add. [String](../../sql-reference/data-types/string.md).
+    Possible values:
+
+    - `second`
+    - `minute`
+    - `hour`
+    - `day`
+    - `week`
+    - `month`
+    - `quarter`
+    - `year`
+
+**Returned value**
+
+Date or date with time with the specified `value` expressed in `unit` added to `date`.
+
+Type: [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Example**
+
+Query:
+
+```sql
+select timestamp_add(toDate('2018-01-01'), INTERVAL 3 MONTH);
+```
+
+Result:
+
+```text
+┌─plus(toDate('2018-01-01'), toIntervalMonth(3))─┐
+│                                     2018-04-01 │
+└────────────────────────────────────────────────┘
+```
+
+## timestamp\_sub {#timestamp_sub}
+
+Subtracts the time interval from the provided date or date with time.
+
+**Syntax**
+
+``` sql
+timestamp_sub(unit, value, date)
+```
+
+Aliases: `timeStampSub`, `TIMESTAMP_SUB`.
+
+**Arguments**
+
+-   `unit` — The type of interval to subtract. [String](../../sql-reference/data-types/string.md).
+    Possible values:
+
+    - `second`
+    - `minute`
+    - `hour`
+    - `day`
+    - `week`
+    - `month`
+    - `quarter`
+    - `year`
+
+-   `value` — Value of interval to subtract. [Int](../../sql-reference/data-types/int-uint.md).
+-   `date` — Date or date with time. [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+Date or date with time obtained by subtracting `value`, expressed in `unit`, from `date`.
+
+Type: [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Example**
+
+Query:
+
+```sql
+select timestamp_sub(MONTH, 5, toDateTime('2018-12-18 01:02:03'));
+```
+
+Result:
+
+```text
+┌─minus(toDateTime('2018-12-18 01:02:03'), toIntervalMonth(5))─┐
+│                                          2018-07-18 01:02:03 │
+└──────────────────────────────────────────────────────────────┘
+```
+
+## now {#now}
+
+Returns the current date and time.
+
+**Syntax**
+
+``` sql
+now([timezone])
+```
+
+**Arguments**
+
+-   `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional). [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Current date and time.
+
+Type: [Datetime](../../sql-reference/data-types/datetime.md).
+
+**Example**
+
+Query without timezone:
+
+``` sql
+SELECT now();
+```
+
+Result:
+
+``` text
+┌───────────────now()─┐
+│ 2020-10-17 07:42:09 │
+└─────────────────────┘
+```
+
+Query with the specified timezone:
+
+``` sql
+SELECT now('Asia/Istanbul');
+```
+
+Result:
+
+``` text
+┌─now('Asia/Istanbul')─┐
+│  2020-10-17 10:42:23 │
+└──────────────────────┘
+```
+
+## today {#today}
+
+Accepts zero arguments and returns the current date at one of the moments of request execution.
+The same as ‘toDate(now())’.
+
+## yesterday {#yesterday}
+
+Accepts zero arguments and returns yesterday’s date at one of the moments of request execution.
+The same as ‘today() - 1’.
+
+## timeSlot {#timeslot}
+
+Rounds the time to the half hour.
+
+## toYYYYMM {#toyyyymm}
+
+Converts a date or date with time to a UInt32 number containing the year and month number (YYYY \* 100 + MM).
+
+## toYYYYMMDD {#toyyyymmdd}
+
+Converts a date or date with time to a UInt32 number containing the year and month number (YYYY \* 10000 + MM \* 100 + DD).
+
+## toYYYYMMDDhhmmss {#toyyyymmddhhmmss}
+
+Converts a date or date with time to a UInt64 number containing the year and month number (YYYY \* 10000000000 + MM \* 100000000 + DD \* 1000000 + hh \* 10000 + mm \* 100 + ss).
+
+## addYears, addMonths, addWeeks, addDays, addHours, addMinutes, addSeconds, addQuarters {#addyears-addmonths-addweeks-adddays-addhours-addminutes-addseconds-addquarters}
+
+Function adds a Date/DateTime interval to a Date/DateTime and then return the Date/DateTime. For example:
+
+``` sql
+WITH
+    toDate('2018-01-01') AS date,
+    toDateTime('2018-01-01 00:00:00') AS date_time
+SELECT
+    addYears(date, 1) AS add_years_with_date,
+    addYears(date_time, 1) AS add_years_with_date_time
+```
+
+``` text
+┌─add_years_with_date─┬─add_years_with_date_time─┐
+│          2019-01-01 │      2019-01-01 00:00:00 │
+└─────────────────────┴──────────────────────────┘
+```
+
+## subtractYears, subtractMonths, subtractWeeks, subtractDays, subtractHours, subtractMinutes, subtractSeconds, subtractQuarters {#subtractyears-subtractmonths-subtractweeks-subtractdays-subtracthours-subtractminutes-subtractseconds-subtractquarters}
+
+Function subtract a Date/DateTime interval to a Date/DateTime and then return the Date/DateTime. For example:
+
+``` sql
+WITH
+    toDate('2019-01-01') AS date,
+    toDateTime('2019-01-01 00:00:00') AS date_time
+SELECT
+    subtractYears(date, 1) AS subtract_years_with_date,
+    subtractYears(date_time, 1) AS subtract_years_with_date_time
+```
+
+``` text
+┌─subtract_years_with_date─┬─subtract_years_with_date_time─┐
+│               2018-01-01 │           2018-01-01 00:00:00 │
+└──────────────────────────┴───────────────────────────────┘
+```
+
+## timeSlots(StartTime, Duration,\[, Size\]) {#timeslotsstarttime-duration-size}
+
+For a time interval starting at ‘StartTime’ and continuing for ‘Duration’ seconds, it returns an array of moments in time, consisting of points from this interval rounded down to the ‘Size’ in seconds. ‘Size’ is an optional parameter: a constant UInt32, set to 1800 by default.
+For example, `timeSlots(toDateTime('2012-01-01 12:20:00'), 600) = [toDateTime('2012-01-01 12:00:00'), toDateTime('2012-01-01 12:30:00')]`.
+This is necessary for searching for pageviews in the corresponding session.
+
+## formatDateTime {#formatdatetime}
+
+Formats a Time according to the given Format string. Format is a constant expression, so you cannot have multiple formats for a single result column.
+
+**Syntax**
+
+``` sql
+formatDateTime(Time, Format\[, Timezone\])
+```
+
+**Returned value(s)**
+
+Returns time and date values according to the determined format.
+
+**Replacement fields**
+Using replacement fields, you can define a pattern for the resulting string. “Example” column shows formatting result for `2018-01-02 22:33:44`.
+
+| Placeholder | Description                                             | Example    |
+|----------|---------------------------------------------------------|------------|
+| %C       | year divided by 100 and truncated to integer (00-99)    | 20         |
+| %d       | day of the month, zero-padded (01-31)                   | 02         |
+| %D       | Short MM/DD/YY date, equivalent to %m/%d/%y             | 01/02/18   |
+| %e       | day of the month, space-padded ( 1-31)                  | &nbsp; 2   |
+| %F       | short YYYY-MM-DD date, equivalent to %Y-%m-%d           | 2018-01-02 |
+| %G       | four-digit year format for ISO week number, calculated from the week-based year [defined by the ISO 8601](https://en.wikipedia.org/wiki/ISO_8601#Week_dates) standard, normally useful only with %V  | 2018         |
+| %g       | two-digit year format, aligned to ISO 8601, abbreviated from four-digit notation                                | 18       |
+| %H       | hour in 24h format (00-23)                              | 22         |
+| %I       | hour in 12h format (01-12)                              | 10         |
+| %j       | day of the year (001-366)                               | 002        |
+| %m       | month as a decimal number (01-12)                       | 01         |
+| %M       | minute (00-59)                                          | 33         |
+| %n       | new-line character (‘’)                                 |            |
+| %p       | AM or PM designation                                    | PM         |
+| %Q       | Quarter (1-4)                                           | 1          |
+| %R       | 24-hour HH:MM time, equivalent to %H:%M                 | 22:33      |
+| %S       | second (00-59)                                          | 44         |
+| %t       | horizontal-tab character (’)                            |            |
+| %T       | ISO 8601 time format (HH:MM:SS), equivalent to %H:%M:%S | 22:33:44   |
+| %u       | ISO 8601 weekday as number with Monday as 1 (1-7)       | 2          |
+| %V       | ISO 8601 week number (01-53)                            | 01         |
+| %w       | weekday as a decimal number with Sunday as 0 (0-6)      | 2          |
+| %y       | Year, last two digits (00-99)                           | 18         |
+| %Y       | Year                                                    | 2018       |
+| %%       | a % sign                                                | %          |
+
+**Example**
+
+Query:
+
+``` sql
+SELECT formatDateTime(toDate('2010-01-04'), '%g')
+```
+
+Result:
+
+```
+┌─formatDateTime(toDate('2010-01-04'), '%g')─┐
+│ 10                                         │
+└────────────────────────────────────────────┘
+```
+
+## dateName {#dataname}
+
+Returns specified part of date.
+
+**Syntax**
+
+``` sql
+dateName(date_part, date)
+```
+
+**Arguments**
+
+-   `date_part` — Date part. Possible values: 'year', 'quarter', 'month', 'week', 'dayofyear', 'day', 'weekday', 'hour', 'minute', 'second'. [String](../../sql-reference/data-types/string.md).
+-   `date` — Date. [Date](../../sql-reference/data-types/date.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
+-   `timezone` — Timezone. Optional. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   The specified part of date.
+
+Type: [String](../../sql-reference/data-types/string.md#string)
+
+**Example**
+
+Query:
+
+```sql
+WITH toDateTime('2021-04-14 11:22:33') AS date_value
+SELECT dateName('year', date_value), dateName('month', date_value), dateName('day', date_value);
+```
+
+Result:
+
+```text
+┌─dateName('year', date_value)─┬─dateName('month', date_value)─┬─dateName('day', date_value)─┐
+│ 2021                         │ April                         │ 14                          │
+└──────────────────────────────┴───────────────────────────────┴─────────────────────────────
+```
+
+## FROM\_UNIXTIME {#fromunixfime}
+
+Function converts Unix timestamp to a calendar date and a time of a day. When there is only a single argument of [Integer](../../sql-reference/data-types/int-uint.md) type, it acts in the same way as [toDateTime](../../sql-reference/functions/type-conversion-functions.md#todatetime) and return [DateTime](../../sql-reference/data-types/datetime.md) type.
+
+**Example:**
+
+Query:
+
+```sql
+SELECT FROM_UNIXTIME(423543535);
+```
+
+Result:
+
+```text
+┌─FROM_UNIXTIME(423543535)─┐
+│      1983-06-04 10:58:55 │
+└──────────────────────────┘
+```
+
+When there are two arguments: first is an [Integer](../../sql-reference/data-types/int-uint.md) or [DateTime](../../sql-reference/data-types/datetime.md), second is a constant format string — it acts in the same way as [formatDateTime](#formatdatetime) and return [String](../../sql-reference/data-types/string.md#string) type.
+
+For example:
+
+```sql
+SELECT FROM_UNIXTIME(1234334543, '%Y-%m-%d %R:%S') AS DateTime;
+```
+
+```text
+┌─DateTime────────────┐
+│ 2009-02-11 14:42:23 │
+└─────────────────────┘
+```
+
+## toModifiedJulianDay {#tomodifiedjulianday}
+
+Converts a [Proleptic Gregorian calendar](https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar) date in text form `YYYY-MM-DD` to a [Modified Julian Day](https://en.wikipedia.org/wiki/Julian_day#Variants) number in Int32. This function supports date from `0000-01-01` to `9999-12-31`. It raises an exception if the argument cannot be parsed as a date, or the date is invalid.
+
+**Syntax**
+
+``` sql
+toModifiedJulianDay(date)
+```
+
+**Arguments**
+
+-   `date` — Date in text form. [String](../../sql-reference/data-types/string.md) or [FixedString](../../sql-reference/data-types/fixedstring.md).
+
+**Returned value**
+
+-   Modified Julian Day number.
+
+Type: [Int32](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toModifiedJulianDay('2020-01-01');
+```
+
+Result:
+
+``` text
+┌─toModifiedJulianDay('2020-01-01')─┐
+│                             58849 │
+└───────────────────────────────────┘
+```
+
+## toModifiedJulianDayOrNull {#tomodifiedjuliandayornull}
+
+Similar to [toModifiedJulianDay()](#tomodifiedjulianday), but instead of raising exceptions it returns `NULL`.
+
+**Syntax**
+
+``` sql
+toModifiedJulianDayOrNull(date)
+```
+
+**Arguments**
+
+-   `date` — Date in text form. [String](../../sql-reference/data-types/string.md) or [FixedString](../../sql-reference/data-types/fixedstring.md).
+
+**Returned value**
+
+-   Modified Julian Day number.
+
+Type: [Nullable(Int32)](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toModifiedJulianDayOrNull('2020-01-01');
+```
+
+Result:
+
+``` text
+┌─toModifiedJulianDayOrNull('2020-01-01')─┐
+│                                   58849 │
+└─────────────────────────────────────────┘
+```
+
+## fromModifiedJulianDay {#frommodifiedjulianday}
+
+Converts a [Modified Julian Day](https://en.wikipedia.org/wiki/Julian_day#Variants) number to a [Proleptic Gregorian calendar](https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar) date in text form `YYYY-MM-DD`. This function supports day number from `-678941` to `2973119` (which represent 0000-01-01 and 9999-12-31 respectively). It raises an exception if the day number is outside of the supported range.
+
+**Syntax**
+
+``` sql
+fromModifiedJulianDay(day)
+```
+
+**Arguments**
+
+-   `day` — Modified Julian Day number. [Any integral types](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Date in text form.
+
+Type: [String](../../sql-reference/data-types/string.md)
+
+**Example**
+
+Query:
+
+``` sql
+SELECT fromModifiedJulianDay(58849);
+```
+
+Result:
+
+``` text
+┌─fromModifiedJulianDay(58849)─┐
+│ 2020-01-01                   │
+└──────────────────────────────┘
+```
+
+## fromModifiedJulianDayOrNull {#frommodifiedjuliandayornull}
+
+Similar to [fromModifiedJulianDayOrNull()](#frommodifiedjuliandayornull), but instead of raising exceptions it returns `NULL`.
+
+**Syntax**
+
+``` sql
+fromModifiedJulianDayOrNull(day)
+```
+
+**Arguments**
+
+-   `day` — Modified Julian Day number. [Any integral types](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Date in text form.
+
+Type: [Nullable(String)](../../sql-reference/data-types/string.md)
+
+**Example**
+
+Query:
+
+``` sql
+SELECT fromModifiedJulianDayOrNull(58849);
+```
+
+Result:
+
+``` text
+┌─fromModifiedJulianDayOrNull(58849)─┐
+│ 2020-01-01                         │
+└────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/encoding-functions.md b/docs/en/reference/sql-reference/functions/encoding-functions.md
new file mode 100644
index 00000000000..6e25befcbc7
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/encoding-functions.md
@@ -0,0 +1,442 @@
+---
+sidebar_position: 52
+sidebar_label: Encoding
+---
+
+# Encoding Functions {#encoding-functions}
+
+## char {#char}
+
+Returns the string with the length as the number of passed arguments and each byte has the value of corresponding argument. Accepts multiple arguments of numeric types. If the value of argument is out of range of UInt8 data type, it is converted to UInt8 with possible rounding and overflow.
+
+**Syntax**
+
+``` sql
+char(number_1, [number_2, ..., number_n]);
+```
+
+**Arguments**
+
+-   `number_1, number_2, ..., number_n` — Numerical arguments interpreted as integers. Types: [Int](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   a string of given bytes.
+
+Type: `String`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT char(104.1, 101, 108.9, 108.9, 111) AS hello;
+```
+
+Result:
+
+``` text
+┌─hello─┐
+│ hello │
+└───────┘
+```
+
+You can construct a string of arbitrary encoding by passing the corresponding bytes. Here is example for UTF-8:
+
+Query:
+
+``` sql
+SELECT char(0xD0, 0xBF, 0xD1, 0x80, 0xD0, 0xB8, 0xD0, 0xB2, 0xD0, 0xB5, 0xD1, 0x82) AS hello;
+```
+
+Result:
+
+``` text
+┌─hello──┐
+│ привет │
+└────────┘
+```
+
+Query:
+
+``` sql
+SELECT char(0xE4, 0xBD, 0xA0, 0xE5, 0xA5, 0xBD) AS hello;
+```
+
+Result:
+
+``` text
+┌─hello─┐
+│ 你好  │
+└───────┘
+```
+
+## hex {#hex}
+
+Returns a string containing the argument’s hexadecimal representation.
+
+Alias: `HEX`.
+
+**Syntax**
+
+``` sql
+hex(arg)
+```
+
+The function is using uppercase letters `A-F` and not using any prefixes (like `0x`) or suffixes (like `h`).
+
+For integer arguments, it prints hex digits (“nibbles”) from the most significant to least significant (big-endian or “human-readable” order). It starts with the most significant non-zero byte (leading zero bytes are omitted) but always prints both digits of every byte even if the leading digit is zero.
+
+Values of type [Date](../../sql-reference/data-types/date.md) and [DateTime](../../sql-reference/data-types/datetime.md) are formatted as corresponding integers (the number of days since Epoch for Date and the value of Unix Timestamp for DateTime).
+
+For [String](../../sql-reference/data-types/string.md) and [FixedString](../../sql-reference/data-types/fixedstring.md), all bytes are simply encoded as two hexadecimal numbers. Zero bytes are not omitted.
+
+Values of [Float](../../sql-reference/data-types/float.md) and [Decimal](../../sql-reference/data-types/decimal.md) types are encoded as their representation in memory. As we support little-endian architecture, they are encoded in little-endian. Zero leading/trailing bytes are not omitted.
+
+Values of [UUID](../data-types/uuid.md) type are encoded as big-endian order string.
+
+**Arguments**
+
+-   `arg` — A value to convert to hexadecimal. Types: [String](../../sql-reference/data-types/string.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md), [Decimal](../../sql-reference/data-types/decimal.md), [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+-   A string with the hexadecimal representation of the argument.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT hex(1);
+```
+
+Result:
+
+``` text
+01
+```
+
+Query:
+
+``` sql
+SELECT hex(toFloat32(number)) AS hex_presentation FROM numbers(15, 2);
+```
+
+Result:
+
+``` text
+┌─hex_presentation─┐
+│ 00007041         │
+│ 00008041         │
+└──────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT hex(toFloat64(number)) AS hex_presentation FROM numbers(15, 2);
+```
+
+Result:
+
+``` text
+┌─hex_presentation─┐
+│ 0000000000002E40 │
+│ 0000000000003040 │
+└──────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT lower(hex(toUUID('61f0c404-5cb3-11e7-907b-a6006ad3dba0'))) as uuid_hex
+```
+
+Result:
+
+``` text
+┌─uuid_hex─────────────────────────┐
+│ 61f0c4045cb311e7907ba6006ad3dba0 │
+└──────────────────────────────────┘
+```
+
+
+## unhex {#unhexstr}
+
+Performs the opposite operation of [hex](#hex). It interprets each pair of hexadecimal digits (in the argument) as a number and converts it to the byte represented by the number. The return value is a binary string (BLOB).
+
+If you want to convert the result to a number, you can use the [reverse](../../sql-reference/functions/string-functions.md#reverse) and [reinterpretAs&lt;Type&gt;](../../sql-reference/functions/type-conversion-functions.md#type-conversion-functions) functions.
+
+:::note    
+If `unhex` is invoked from within the `clickhouse-client`, binary strings display using UTF-8.
+:::
+
+Alias: `UNHEX`.
+
+**Syntax**
+
+``` sql
+unhex(arg)
+```
+
+**Arguments**
+
+-   `arg` — A string containing any number of hexadecimal digits. Type: [String](../../sql-reference/data-types/string.md).
+
+Supports both uppercase and lowercase letters `A-F`. The number of hexadecimal digits does not have to be even. If it is odd, the last digit is interpreted as the least significant half of the `00-0F` byte. If the argument string contains anything other than hexadecimal digits, some implementation-defined result is returned (an exception isn’t thrown). For a numeric argument the inverse of hex(N) is not performed by unhex().
+
+**Returned value**
+
+-   A binary string (BLOB).
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+``` sql
+SELECT unhex('303132'), UNHEX('4D7953514C');
+```
+
+Result:
+``` text
+┌─unhex('303132')─┬─unhex('4D7953514C')─┐
+│ 012             │ MySQL               │
+└─────────────────┴─────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT reinterpretAsUInt64(reverse(unhex('FFF'))) AS num;
+```
+
+Result:
+
+``` text
+┌──num─┐
+│ 4095 │
+└──────┘
+```
+
+## bin {#bin}
+
+Returns a string containing the argument’s binary representation.
+
+**Syntax**
+
+``` sql
+bin(arg)
+```
+
+Alias: `BIN`.
+
+For integer arguments, it prints bin digits from the most significant to least significant (big-endian or “human-readable” order). It starts with the most significant non-zero byte (leading zero bytes are omitted) but always prints eight digits of every byte if the leading digit is zero.
+
+Values of type [Date](../../sql-reference/data-types/date.md) and [DateTime](../../sql-reference/data-types/datetime.md) are formatted as corresponding integers (the number of days since Epoch for `Date` and the value of Unix Timestamp for `DateTime`).
+
+For [String](../../sql-reference/data-types/string.md) and [FixedString](../../sql-reference/data-types/fixedstring.md), all bytes are simply encoded as eight binary numbers. Zero bytes are not omitted.
+
+Values of [Float](../../sql-reference/data-types/float.md) and [Decimal](../../sql-reference/data-types/decimal.md) types are encoded as their representation in memory. As we support little-endian architecture, they are encoded in little-endian. Zero leading/trailing bytes are not omitted.
+
+Values of [UUID](../data-types/uuid.md) type are encoded as big-endian order string.
+
+**Arguments**
+
+-   `arg` — A value to convert to binary. [String](../../sql-reference/data-types/string.md), [FixedString](../../sql-reference/data-types/fixedstring.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md), [Decimal](../../sql-reference/data-types/decimal.md), [Date](../../sql-reference/data-types/date.md), or [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+-   A string with the binary representation of the argument.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT bin(14);
+```
+
+Result:
+
+``` text
+┌─bin(14)──┐
+│ 00001110 │
+└──────────┘
+```
+
+Query:
+
+``` sql
+SELECT bin(toFloat32(number)) AS bin_presentation FROM numbers(15, 2);
+```
+
+Result:
+
+``` text
+┌─bin_presentation─────────────────┐
+│ 00000000000000000111000001000001 │
+│ 00000000000000001000000001000001 │
+└──────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT bin(toFloat64(number)) AS bin_presentation FROM numbers(15, 2);
+```
+
+Result:
+
+``` text
+┌─bin_presentation─────────────────────────────────────────────────┐
+│ 0000000000000000000000000000000000000000000000000010111001000000 │
+│ 0000000000000000000000000000000000000000000000000011000001000000 │
+└──────────────────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT bin(toUUID('61f0c404-5cb3-11e7-907b-a6006ad3dba0')) as bin_uuid
+```
+
+Result:
+
+``` text
+┌─bin_uuid─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ 01100001111100001100010000000100010111001011001100010001111001111001000001111011101001100000000001101010110100111101101110100000 │
+└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+
+## unbin {#unbinstr}
+
+Interprets each pair of binary digits (in the argument) as a number and converts it to the byte represented by the number. The functions performs the opposite operation to [bin](#bin).
+
+**Syntax**
+
+``` sql
+unbin(arg)
+```
+
+Alias: `UNBIN`.
+
+For a numeric argument `unbin()` does not return the inverse of `bin()`. If you want to convert the result to a number, you can use the [reverse](../../sql-reference/functions/string-functions.md#reverse) and [reinterpretAs&lt;Type&gt;](../../sql-reference/functions/type-conversion-functions.md#reinterpretasuint8163264) functions.
+
+:::note    
+If `unbin` is invoked from within the `clickhouse-client`, binary strings are displayed using UTF-8.
+:::
+
+Supports binary digits `0` and `1`. The number of binary digits does not have to be multiples of eight. If the argument string contains anything other than binary digits, some implementation-defined result is returned (an exception isn’t thrown). 
+
+**Arguments**
+
+-   `arg` — A string containing any number of binary digits. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   A binary string (BLOB).
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT UNBIN('001100000011000100110010'), UNBIN('0100110101111001010100110101000101001100');
+```
+
+Result:
+
+``` text
+┌─unbin('001100000011000100110010')─┬─unbin('0100110101111001010100110101000101001100')─┐
+│ 012                               │ MySQL                                             │
+└───────────────────────────────────┴───────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT reinterpretAsUInt64(reverse(unbin('1110'))) AS num;
+```
+
+Result:
+
+``` text
+┌─num─┐
+│  14 │
+└─────┘
+```
+
+## UUIDStringToNum(str) {#uuidstringtonumstr}
+
+Accepts a string containing 36 characters in the format `123e4567-e89b-12d3-a456-426655440000`, and returns it as a set of bytes in a FixedString(16).
+
+## UUIDNumToString(str) {#uuidnumtostringstr}
+
+Accepts a FixedString(16) value. Returns a string containing 36 characters in text format.
+
+## bitmaskToList(num) {#bitmasktolistnum}
+
+Accepts an integer. Returns a string containing the list of powers of two that total the source number when summed. They are comma-separated without spaces in text format, in ascending order.
+
+## bitmaskToArray(num) {#bitmasktoarraynum}
+
+Accepts an integer. Returns an array of UInt64 numbers containing the list of powers of two that total the source number when summed. Numbers in the array are in ascending order.
+
+## bitPositionsToArray(num) {#bitpositionstoarraynum}
+
+Accepts an integer and converts it to an unsigned integer. Returns an array of `UInt64` numbers containing the list of positions of bits of `arg` that equal `1`, in ascending order.
+
+**Syntax**
+
+```sql
+bitPositionsToArray(arg)
+```
+
+**Arguments**
+
+-   `arg` — Integer value. [Int/UInt](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   An array containing a list of positions of bits that equal `1`, in ascending order.
+
+Type: [Array](../../sql-reference/data-types/array.md)([UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT bitPositionsToArray(toInt8(1)) AS bit_positions;
+```
+
+Result:
+
+``` text
+┌─bit_positions─┐
+│ [0]           │
+└───────────────┘
+```
+
+Query:
+
+``` sql
+SELECT bitPositionsToArray(toInt8(-1)) AS bit_positions;
+```
+
+Result:
+
+``` text
+┌─bit_positions─────┐
+│ [0,1,2,3,4,5,6,7] │
+└───────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/encryption-functions.md b/docs/en/reference/sql-reference/functions/encryption-functions.md
new file mode 100644
index 00000000000..942a63a48a8
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/encryption-functions.md
@@ -0,0 +1,361 @@
+---
+sidebar_position: 67
+sidebar_label: Encryption
+---
+
+# Encryption functions {#encryption-functions}
+
+These functions  implement encryption and decryption of data with AES (Advanced Encryption Standard) algorithm.
+
+Key length depends on encryption mode. It is 16, 24, and 32 bytes long for `-128-`, `-196-`, and `-256-` modes respectively.
+
+Initialization vector length is always 16 bytes (bytes in excess of 16 are ignored).
+
+Note that these functions work slowly until ClickHouse 21.1.
+
+## encrypt {#encrypt}
+
+This function encrypts data using these modes:
+
+-   aes-128-ecb, aes-192-ecb, aes-256-ecb
+-   aes-128-cbc, aes-192-cbc, aes-256-cbc
+-   aes-128-cfb1, aes-192-cfb1, aes-256-cfb1
+-   aes-128-cfb8, aes-192-cfb8, aes-256-cfb8
+-   aes-128-cfb128, aes-192-cfb128, aes-256-cfb128
+-   aes-128-ofb, aes-192-ofb, aes-256-ofb
+-   aes-128-gcm, aes-192-gcm, aes-256-gcm
+
+**Syntax**
+
+``` sql
+encrypt('mode', 'plaintext', 'key' [, iv, aad])
+```
+
+**Arguments**
+
+-   `mode` — Encryption mode. [String](../../sql-reference/data-types/string.md#string).
+-   `plaintext` — Text thats need to be encrypted. [String](../../sql-reference/data-types/string.md#string).
+-   `key` — Encryption key. [String](../../sql-reference/data-types/string.md#string).
+-   `iv` — Initialization vector. Required for `-gcm` modes, optinal for others. [String](../../sql-reference/data-types/string.md#string).
+-   `aad` — Additional authenticated data. It isn't encrypted, but it affects decryption. Works only in `-gcm` modes, for others would throw an exception. [String](../../sql-reference/data-types/string.md#string).
+
+**Returned value**
+
+-   Ciphertext binary string. [String](../../sql-reference/data-types/string.md#string).
+
+**Examples**
+
+Create this table:
+
+Query:
+
+``` sql
+CREATE TABLE encryption_test
+(
+    `comment` String,
+    `secret` String
+)
+ENGINE = Memory;
+```
+
+Insert some data (please avoid storing the keys/ivs in the database as this undermines the whole concept of encryption), also storing 'hints' is unsafe too and used only for illustrative purposes:
+
+Query:
+
+``` sql
+INSERT INTO encryption_test VALUES('aes-256-cfb128 no IV', encrypt('aes-256-cfb128', 'Secret', '12345678910121314151617181920212')),\
+('aes-256-cfb128 no IV, different key', encrypt('aes-256-cfb128', 'Secret', 'keykeykeykeykeykeykeykeykeykeyke')),\
+('aes-256-cfb128 with IV', encrypt('aes-256-cfb128', 'Secret', '12345678910121314151617181920212', 'iviviviviviviviv')),\
+('aes-256-cbc no IV', encrypt('aes-256-cbc', 'Secret', '12345678910121314151617181920212'));
+```
+
+Query:
+
+``` sql
+SELECT comment, hex(secret) FROM encryption_test;
+```
+
+Result:
+
+``` text
+┌─comment─────────────────────────────┬─hex(secret)──────────────────────┐
+│ aes-256-cfb128 no IV                │ B4972BDC4459                     │
+│ aes-256-cfb128 no IV, different key │ 2FF57C092DC9                     │
+│ aes-256-cfb128 with IV              │ 5E6CB398F653                     │
+│ aes-256-cbc no IV                   │ 1BC0629A92450D9E73A00E7D02CF4142 │
+└─────────────────────────────────────┴──────────────────────────────────┘
+```
+
+Example with `-gcm`:
+
+Query:
+
+``` sql
+INSERT INTO encryption_test VALUES('aes-256-gcm', encrypt('aes-256-gcm', 'Secret', '12345678910121314151617181920212', 'iviviviviviviviv')), \
+('aes-256-gcm with AAD', encrypt('aes-256-gcm', 'Secret', '12345678910121314151617181920212', 'iviviviviviviviv', 'aad'));
+
+SELECT comment, hex(secret) FROM encryption_test WHERE comment LIKE '%gcm%';
+```
+
+Result:
+
+``` text
+┌─comment──────────────┬─hex(secret)──────────────────────────────────┐
+│ aes-256-gcm          │ A8A3CCBC6426CFEEB60E4EAE03D3E94204C1B09E0254 │
+│ aes-256-gcm with AAD │ A8A3CCBC6426D9A1017A0A932322F1852260A4AD6837 │
+└──────────────────────┴──────────────────────────────────────────────┘
+```
+
+## aes_encrypt_mysql {#aes_encrypt_mysql}
+
+Compatible with mysql encryption and resulting ciphertext can be decrypted with [AES_DECRYPT](https://dev.mysql.com/doc/refman/8.0/en/encryption-functions.html#function_aes-decrypt) function.
+
+Will produce the same ciphertext as `encrypt` on equal inputs. But when `key` or `iv` are longer than they should normally be, `aes_encrypt_mysql` will stick to what MySQL's `aes_encrypt` does: 'fold' `key` and ignore excess bits of `iv`.
+
+Supported encryption modes:
+
+-   aes-128-ecb, aes-192-ecb, aes-256-ecb
+-   aes-128-cbc, aes-192-cbc, aes-256-cbc
+-   aes-128-cfb1, aes-192-cfb1, aes-256-cfb1
+-   aes-128-cfb8, aes-192-cfb8, aes-256-cfb8
+-   aes-128-cfb128, aes-192-cfb128, aes-256-cfb128
+-   aes-128-ofb, aes-192-ofb, aes-256-ofb
+
+**Syntax**
+
+``` sql
+aes_encrypt_mysql('mode', 'plaintext', 'key' [, iv])
+```
+
+**Arguments**
+
+-   `mode` — Encryption mode. [String](../../sql-reference/data-types/string.md#string).
+-   `plaintext` — Text that needs to be encrypted. [String](../../sql-reference/data-types/string.md#string).
+-   `key` — Encryption key. If key is longer than required by mode, MySQL-specific key folding is performed. [String](../../sql-reference/data-types/string.md#string).
+-   `iv` — Initialization vector. Optional, only first 16 bytes are taken into account [String](../../sql-reference/data-types/string.md#string).
+
+**Returned value**
+
+- Ciphertext binary string. [String](../../sql-reference/data-types/string.md#string).
+
+**Examples**
+
+Given equal input `encrypt` and `aes_encrypt_mysql` produce the same ciphertext:
+
+Query:
+
+``` sql
+SELECT encrypt('aes-256-cfb128', 'Secret', '12345678910121314151617181920212', 'iviviviviviviviv') = aes_encrypt_mysql('aes-256-cfb128', 'Secret', '12345678910121314151617181920212', 'iviviviviviviviv') AS ciphertexts_equal;
+```
+
+Result:
+
+```
+┌─ciphertexts_equal─┐
+│                 1 │
+└───────────────────┘
+```
+
+But `encrypt` fails when `key` or `iv` is longer than expected:
+
+Query:
+
+``` sql
+SELECT encrypt('aes-256-cfb128', 'Secret', '123456789101213141516171819202122', 'iviviviviviviviv123');
+```
+
+Result:
+
+``` text
+Received exception from server (version 21.1.2):
+Code: 36. DB::Exception: Received from localhost:9000. DB::Exception: Invalid key size: 33 expected 32: While processing encrypt('aes-256-cfb128', 'Secret', '123456789101213141516171819202122', 'iviviviviviviviv123').
+```
+
+While `aes_encrypt_mysql` produces MySQL-compatitalbe output:
+
+Query:
+
+``` sql
+SELECT hex(aes_encrypt_mysql('aes-256-cfb128', 'Secret', '123456789101213141516171819202122', 'iviviviviviviviv123')) AS ciphertext;
+```
+
+Result:
+
+```text
+┌─ciphertext───┐
+│ 24E9E4966469 │
+└──────────────┘
+```
+
+Notice how supplying even longer `IV` produces the same result
+
+Query:
+
+``` sql
+SELECT hex(aes_encrypt_mysql('aes-256-cfb128', 'Secret', '123456789101213141516171819202122', 'iviviviviviviviv123456')) AS ciphertext
+```
+
+Result:
+
+``` text
+┌─ciphertext───┐
+│ 24E9E4966469 │
+└──────────────┘
+```
+
+Which is binary equal to what MySQL produces on same inputs:
+
+``` sql
+mysql> SET  block_encryption_mode='aes-256-cfb128';
+Query OK, 0 rows affected (0.00 sec)
+
+mysql> SELECT aes_encrypt('Secret', '123456789101213141516171819202122', 'iviviviviviviviv123456') as ciphertext;
++------------------------+
+| ciphertext             |
++------------------------+
+| 0x24E9E4966469         |
++------------------------+
+1 row in set (0.00 sec)
+```
+
+## decrypt {#decrypt}
+
+This function decrypts ciphertext into a plaintext using these modes:
+
+-   aes-128-ecb, aes-192-ecb, aes-256-ecb
+-   aes-128-cbc, aes-192-cbc, aes-256-cbc
+-   aes-128-cfb1, aes-192-cfb1, aes-256-cfb1
+-   aes-128-cfb8, aes-192-cfb8, aes-256-cfb8
+-   aes-128-cfb128, aes-192-cfb128, aes-256-cfb128
+-   aes-128-ofb, aes-192-ofb, aes-256-ofb
+-   aes-128-gcm, aes-192-gcm, aes-256-gcm
+
+**Syntax**
+
+``` sql
+decrypt('mode', 'ciphertext', 'key' [, iv, aad])
+```
+
+**Arguments**
+
+-   `mode` — Decryption mode. [String](../../sql-reference/data-types/string.md#string).
+-   `ciphertext` — Encrypted text that needs to be decrypted. [String](../../sql-reference/data-types/string.md#string).
+-   `key` — Decryption key. [String](../../sql-reference/data-types/string.md#string).
+-   `iv` — Initialization vector. Required for `-gcm` modes, optinal for others. [String](../../sql-reference/data-types/string.md#string).
+-   `aad` — Additional authenticated data. Won't decrypt if this value is incorrect. Works only in `-gcm` modes, for others would throw an exception. [String](../../sql-reference/data-types/string.md#string).
+
+**Returned value**
+
+-   Decrypted String. [String](../../sql-reference/data-types/string.md#string).
+
+**Examples**
+
+Re-using table from [encrypt](#encrypt).
+
+Query:
+
+``` sql
+SELECT comment, hex(secret) FROM encryption_test;
+```
+
+Result:
+
+``` text
+┌─comment──────────────┬─hex(secret)──────────────────────────────────┐
+│ aes-256-gcm          │ A8A3CCBC6426CFEEB60E4EAE03D3E94204C1B09E0254 │
+│ aes-256-gcm with AAD │ A8A3CCBC6426D9A1017A0A932322F1852260A4AD6837 │
+└──────────────────────┴──────────────────────────────────────────────┘
+┌─comment─────────────────────────────┬─hex(secret)──────────────────────┐
+│ aes-256-cfb128 no IV                │ B4972BDC4459                     │
+│ aes-256-cfb128 no IV, different key │ 2FF57C092DC9                     │
+│ aes-256-cfb128 with IV              │ 5E6CB398F653                     │
+│ aes-256-cbc no IV                   │ 1BC0629A92450D9E73A00E7D02CF4142 │
+└─────────────────────────────────────┴──────────────────────────────────┘
+```
+
+Now let's try to decrypt all that data.
+
+Query:
+
+``` sql
+SELECT comment, decrypt('aes-256-cfb128', secret, '12345678910121314151617181920212') as plaintext FROM encryption_test
+```
+
+Result:
+
+``` text
+┌─comment─────────────────────────────┬─plaintext─┐
+│ aes-256-cfb128 no IV                │ Secret    │
+│ aes-256-cfb128 no IV, different key │ �4�
+                                           �         │
+│ aes-256-cfb128 with IV              │ ���6�~        │
+ │aes-256-cbc no IV                   │ �2*4�h3c�4w��@
+└─────────────────────────────────────┴───────────┘
+```
+
+Notice how only a portion of the data was properly decrypted, and the rest is gibberish since either `mode`, `key`, or `iv` were different upon encryption.
+
+## aes_decrypt_mysql {#aes_decrypt_mysql}
+
+Compatible with mysql encryption and decrypts data encrypted with [AES_ENCRYPT](https://dev.mysql.com/doc/refman/8.0/en/encryption-functions.html#function_aes-encrypt) function.
+
+Will produce same plaintext as `decrypt` on equal inputs. But when `key` or `iv` are longer than they should normally be, `aes_decrypt_mysql` will stick to what MySQL's `aes_decrypt` does: 'fold' `key` and ignore excess bits of `IV`.
+
+Supported decryption modes:
+
+-   aes-128-ecb, aes-192-ecb, aes-256-ecb
+-   aes-128-cbc, aes-192-cbc, aes-256-cbc
+-   aes-128-cfb1, aes-192-cfb1, aes-256-cfb1
+-   aes-128-cfb8, aes-192-cfb8, aes-256-cfb8
+-   aes-128-cfb128, aes-192-cfb128, aes-256-cfb128
+-   aes-128-ofb, aes-192-ofb, aes-256-ofb
+
+**Syntax**
+
+``` sql
+aes_decrypt_mysql('mode', 'ciphertext', 'key' [, iv])
+```
+
+**Arguments**
+
+-   `mode` — Decryption mode. [String](../../sql-reference/data-types/string.md#string).
+-   `ciphertext` — Encrypted text that needs to be decrypted. [String](../../sql-reference/data-types/string.md#string).
+-   `key` — Decryption key. [String](../../sql-reference/data-types/string.md#string).
+-   `iv` — Initialization vector. Optinal. [String](../../sql-reference/data-types/string.md#string).
+
+**Returned value**
+
+-   Decrypted String. [String](../../sql-reference/data-types/string.md#string).
+
+**Examples**
+
+Let's decrypt data we've previously encrypted with MySQL:
+
+``` sql
+mysql> SET  block_encryption_mode='aes-256-cfb128';
+Query OK, 0 rows affected (0.00 sec)
+
+mysql> SELECT aes_encrypt('Secret', '123456789101213141516171819202122', 'iviviviviviviviv123456') as ciphertext;
++------------------------+
+| ciphertext             |
++------------------------+
+| 0x24E9E4966469         |
++------------------------+
+1 row in set (0.00 sec)
+```
+
+Query:
+
+``` sql
+SELECT aes_decrypt_mysql('aes-256-cfb128', unhex('24E9E4966469'), '123456789101213141516171819202122', 'iviviviviviviviv123456') AS plaintext
+```
+
+Result:
+
+``` text
+┌─plaintext─┐
+│ Secret    │
+└───────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/functions/encryption_functions/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/functions/ext-dict-functions.md b/docs/en/reference/sql-reference/functions/ext-dict-functions.md
new file mode 100644
index 00000000000..1d3f5952c98
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/ext-dict-functions.md
@@ -0,0 +1,444 @@
+---
+sidebar_position: 58
+sidebar_label: External Dictionaries
+---
+
+:::note    
+For dictionaries created with [DDL queries](../../sql-reference/statements/create/dictionary.md), the `dict_name` parameter must be fully specified, like `<database>.<dict_name>`. Otherwise, the current database is used.
+:::
+
+# Functions for Working with External Dictionaries {#ext_dict_functions}
+
+For information on connecting and configuring external dictionaries, see [External dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md).
+
+## dictGet, dictGetOrDefault, dictGetOrNull {#dictget}
+
+Retrieves values from an external dictionary.
+
+``` sql
+dictGet('dict_name', attr_names, id_expr)
+dictGetOrDefault('dict_name', attr_names, id_expr, default_value_expr)
+dictGetOrNull('dict_name', attr_name, id_expr)
+```
+
+**Arguments**
+
+-   `dict_name` — Name of the dictionary. [String literal](../../sql-reference/syntax.md#syntax-string-literal).
+-   `attr_names` — Name of the column of the dictionary, [String literal](../../sql-reference/syntax.md#syntax-string-literal), or tuple of column names, [Tuple](../../sql-reference/data-types/tuple.md)([String literal](../../sql-reference/syntax.md#syntax-string-literal)).
+-   `id_expr` — Key value. [Expression](../../sql-reference/syntax.md#syntax-expressions) returning dictionary key-type value or [Tuple](../../sql-reference/data-types/tuple.md)-type value depending on the dictionary configuration.
+-   `default_value_expr` — Values returned if the dictionary does not contain a row with the `id_expr` key. [Expression](../../sql-reference/syntax.md#syntax-expressions) or [Tuple](../../sql-reference/data-types/tuple.md)([Expression](../../sql-reference/syntax.md#syntax-expressions)), returning the value (or values) in the data types configured for the `attr_names` attribute.
+
+**Returned value**
+
+-   If ClickHouse parses the attribute successfully in the [attribute’s data type](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-attributes), functions return the value of the dictionary attribute that corresponds to `id_expr`.
+
+-   If there is no the key, corresponding to `id_expr`, in the dictionary, then:
+
+        - `dictGet` returns the content of the `<null_value>` element specified for the attribute in the dictionary configuration.
+        - `dictGetOrDefault` returns the value passed as the `default_value_expr` parameter.
+        - `dictGetOrNull` returns `NULL` in case key was not found in dictionary.
+
+ClickHouse throws an exception if it cannot parse the value of the attribute or the value does not match the attribute data type.
+
+**Example for simple key dictionary**
+
+Create a text file `ext-dict-test.csv` containing the following:
+
+``` text
+1,1
+2,2
+```
+
+The first column is `id`, the second column is `c1`.
+
+Configure the external dictionary:
+
+``` xml
+<clickhouse>
+    <dictionary>
+        <name>ext-dict-test</name>
+        <source>
+            <file>
+                <path>/path-to/ext-dict-test.csv</path>
+                <format>CSV</format>
+            </file>
+        </source>
+        <layout>
+            <flat />
+        </layout>
+        <structure>
+            <id>
+                <name>id</name>
+            </id>
+            <attribute>
+                <name>c1</name>
+                <type>UInt32</type>
+                <null_value></null_value>
+            </attribute>
+        </structure>
+        <lifetime>0</lifetime>
+    </dictionary>
+</clickhouse>
+```
+
+Perform the query:
+
+``` sql
+SELECT
+    dictGetOrDefault('ext-dict-test', 'c1', number + 1, toUInt32(number * 10)) AS val,
+    toTypeName(val) AS type
+FROM system.numbers
+LIMIT 3;
+```
+
+``` text
+┌─val─┬─type───┐
+│   1 │ UInt32 │
+│   2 │ UInt32 │
+│  20 │ UInt32 │
+└─────┴────────┘
+```
+
+**Example for complex key dictionary**
+
+Create a text file `ext-dict-mult.csv` containing the following:
+
+``` text
+1,1,'1'
+2,2,'2'
+3,3,'3'
+```
+
+The first column is `id`, the second is `c1`, the third is `c2`.
+
+Configure the external dictionary:
+
+``` xml
+<clickhouse>
+    <dictionary>
+        <name>ext-dict-mult</name>
+        <source>
+            <file>
+                <path>/path-to/ext-dict-mult.csv</path>
+                <format>CSV</format>
+            </file>
+        </source>
+        <layout>
+            <flat />
+        </layout>
+        <structure>
+            <id>
+                <name>id</name>
+            </id>
+            <attribute>
+                <name>c1</name>
+                <type>UInt32</type>
+                <null_value></null_value>
+            </attribute>
+            <attribute>
+                <name>c2</name>
+                <type>String</type>
+                <null_value></null_value>
+            </attribute>
+        </structure>
+        <lifetime>0</lifetime>
+    </dictionary>
+</clickhouse>
+```
+
+Perform the query:
+
+``` sql
+SELECT
+    dictGet('ext-dict-mult', ('c1','c2'), number) AS val,
+    toTypeName(val) AS type
+FROM system.numbers
+LIMIT 3;
+```
+
+``` text
+┌─val─────┬─type──────────────────┐
+│ (1,'1') │ Tuple(UInt8, String)  │
+│ (2,'2') │ Tuple(UInt8, String)  │
+│ (3,'3') │ Tuple(UInt8, String)  │
+└─────────┴───────────────────────┘
+```
+
+**Example for range key dictionary**
+
+Input table:
+
+```sql
+CREATE TABLE range_key_dictionary_source_table
+(
+    key UInt64,
+    start_date Date,
+    end_date Date,
+    value String,
+    value_nullable Nullable(String)
+)
+ENGINE = TinyLog();
+
+INSERT INTO range_key_dictionary_source_table VALUES(1, toDate('2019-05-20'), toDate('2019-05-20'), 'First', 'First');
+INSERT INTO range_key_dictionary_source_table VALUES(2, toDate('2019-05-20'), toDate('2019-05-20'), 'Second', NULL);
+INSERT INTO range_key_dictionary_source_table VALUES(3, toDate('2019-05-20'), toDate('2019-05-20'), 'Third', 'Third');
+```
+
+Create the external dictionary:
+
+```sql
+CREATE DICTIONARY range_key_dictionary
+(
+    key UInt64,
+    start_date Date,
+    end_date Date,
+    value String,
+    value_nullable Nullable(String)
+)
+PRIMARY KEY key
+SOURCE(CLICKHOUSE(HOST 'localhost' PORT tcpPort() TABLE 'range_key_dictionary_source_table'))
+LIFETIME(MIN 1 MAX 1000)
+LAYOUT(RANGE_HASHED())
+RANGE(MIN start_date MAX end_date);
+```
+
+Perform the query:
+
+``` sql
+SELECT
+    (number, toDate('2019-05-20')),
+    dictHas('range_key_dictionary', number, toDate('2019-05-20')),
+    dictGetOrNull('range_key_dictionary', 'value', number, toDate('2019-05-20')),
+    dictGetOrNull('range_key_dictionary', 'value_nullable', number, toDate('2019-05-20')),
+    dictGetOrNull('range_key_dictionary', ('value', 'value_nullable'), number, toDate('2019-05-20'))
+FROM system.numbers LIMIT 5 FORMAT TabSeparated;
+```
+Result:
+
+``` text
+(0,'2019-05-20')        0       \N      \N      (NULL,NULL)
+(1,'2019-05-20')        1       First   First   ('First','First')
+(2,'2019-05-20')        1       Second  \N      ('Second',NULL)
+(3,'2019-05-20')        1       Third   Third   ('Third','Third')
+(4,'2019-05-20')        0       \N      \N      (NULL,NULL)
+```
+
+**See Also**
+
+-   [External Dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md)
+
+## dictHas {#dicthas}
+
+Checks whether a key is present in a dictionary.
+
+``` sql
+dictHas('dict_name', id_expr)
+```
+
+**Arguments**
+
+-   `dict_name` — Name of the dictionary. [String literal](../../sql-reference/syntax.md#syntax-string-literal).
+-   `id_expr` — Key value. [Expression](../../sql-reference/syntax.md#syntax-expressions) returning dictionary key-type value or [Tuple](../../sql-reference/data-types/tuple.md)-type value depending on the dictionary configuration.
+
+**Returned value**
+
+-   0, if there is no key.
+-   1, if there is a key.
+
+Type: `UInt8`.
+
+## dictGetHierarchy {#dictgethierarchy}
+
+Creates an array, containing all the parents of a key in the [hierarchical dictionary](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-hierarchical.md).
+
+**Syntax**
+
+``` sql
+dictGetHierarchy('dict_name', key)
+```
+
+**Arguments**
+
+-   `dict_name` — Name of the dictionary. [String literal](../../sql-reference/syntax.md#syntax-string-literal).
+-   `key` — Key value. [Expression](../../sql-reference/syntax.md#syntax-expressions) returning a [UInt64](../../sql-reference/data-types/int-uint.md)-type value.
+
+**Returned value**
+
+-   Parents for the key.
+
+Type: [Array(UInt64)](../../sql-reference/data-types/array.md).
+
+## dictIsIn {#dictisin}
+
+Checks the ancestor of a key through the whole hierarchical chain in the dictionary.
+
+``` sql
+dictIsIn('dict_name', child_id_expr, ancestor_id_expr)
+```
+
+**Arguments**
+
+-   `dict_name` — Name of the dictionary. [String literal](../../sql-reference/syntax.md#syntax-string-literal).
+-   `child_id_expr` — Key to be checked. [Expression](../../sql-reference/syntax.md#syntax-expressions) returning a [UInt64](../../sql-reference/data-types/int-uint.md)-type value.
+-   `ancestor_id_expr` — Alleged ancestor of the `child_id_expr` key. [Expression](../../sql-reference/syntax.md#syntax-expressions) returning a [UInt64](../../sql-reference/data-types/int-uint.md)-type value.
+
+**Returned value**
+
+-   0, if `child_id_expr` is not a child of `ancestor_id_expr`.
+-   1, if `child_id_expr` is a child of `ancestor_id_expr` or if `child_id_expr` is an `ancestor_id_expr`.
+
+Type: `UInt8`.
+
+## dictGetChildren {#dictgetchildren}
+
+Returns first-level children as an array of indexes. It is the inverse transformation for [dictGetHierarchy](#dictgethierarchy).
+
+**Syntax**
+
+``` sql
+dictGetChildren(dict_name, key)
+```
+
+**Arguments**
+
+-   `dict_name` — Name of the dictionary. [String literal](../../sql-reference/syntax.md#syntax-string-literal).
+-   `key` — Key value. [Expression](../../sql-reference/syntax.md#syntax-expressions) returning a [UInt64](../../sql-reference/data-types/int-uint.md)-type value.
+
+**Returned values**
+
+-   First-level descendants for the key.
+
+Type: [Array](../../sql-reference/data-types/array.md)([UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Consider the hierarchic dictionary:
+
+``` text
+┌─id─┬─parent_id─┐
+│  1 │         0 │
+│  2 │         1 │
+│  3 │         1 │
+│  4 │         2 │
+└────┴───────────┘
+```
+
+First-level children:
+
+``` sql
+SELECT dictGetChildren('hierarchy_flat_dictionary', number) FROM system.numbers LIMIT 4;
+```
+
+``` text
+┌─dictGetChildren('hierarchy_flat_dictionary', number)─┐
+│ [1]                                                  │
+│ [2,3]                                                │
+│ [4]                                                  │
+│ []                                                   │
+└──────────────────────────────────────────────────────┘
+```
+
+## dictGetDescendant {#dictgetdescendant}
+
+Returns all descendants as if [dictGetChildren](#dictgetchildren) function was applied `level` times recursively.
+
+**Syntax**
+
+``` sql
+dictGetDescendants(dict_name, key, level)
+```
+
+**Arguments**
+
+-   `dict_name` — Name of the dictionary. [String literal](../../sql-reference/syntax.md#syntax-string-literal).
+-   `key` — Key value. [Expression](../../sql-reference/syntax.md#syntax-expressions) returning a [UInt64](../../sql-reference/data-types/int-uint.md)-type value.
+-   `level` — Hierarchy level. If `level = 0` returns all descendants to the end. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Descendants for the key.
+
+Type: [Array](../../sql-reference/data-types/array.md)([UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Consider the hierarchic dictionary:
+
+``` text
+┌─id─┬─parent_id─┐
+│  1 │         0 │
+│  2 │         1 │
+│  3 │         1 │
+│  4 │         2 │
+└────┴───────────┘
+```
+All descendants:
+
+``` sql
+SELECT dictGetDescendants('hierarchy_flat_dictionary', number) FROM system.numbers LIMIT 4;
+```
+
+``` text
+┌─dictGetDescendants('hierarchy_flat_dictionary', number)─┐
+│ [1,2,3,4]                                               │
+│ [2,3,4]                                                 │
+│ [4]                                                     │
+│ []                                                      │
+└─────────────────────────────────────────────────────────┘
+```
+
+First-level descendants:
+
+``` sql
+SELECT dictGetDescendants('hierarchy_flat_dictionary', number, 1) FROM system.numbers LIMIT 4;
+```
+
+``` text
+┌─dictGetDescendants('hierarchy_flat_dictionary', number, 1)─┐
+│ [1]                                                        │
+│ [2,3]                                                      │
+│ [4]                                                        │
+│ []                                                         │
+└────────────────────────────────────────────────────────────┘
+```
+
+## Other Functions {#ext_dict_functions-other}
+
+ClickHouse supports specialized functions that convert dictionary attribute values to a specific data type regardless of the dictionary configuration.
+
+Functions:
+
+-   `dictGetInt8`, `dictGetInt16`, `dictGetInt32`, `dictGetInt64`
+-   `dictGetUInt8`, `dictGetUInt16`, `dictGetUInt32`, `dictGetUInt64`
+-   `dictGetFloat32`, `dictGetFloat64`
+-   `dictGetDate`
+-   `dictGetDateTime`
+-   `dictGetUUID`
+-   `dictGetString`
+
+All these functions have the `OrDefault` modification. For example, `dictGetDateOrDefault`.
+
+Syntax:
+
+``` sql
+dictGet[Type]('dict_name', 'attr_name', id_expr)
+dictGet[Type]OrDefault('dict_name', 'attr_name', id_expr, default_value_expr)
+```
+
+**Arguments**
+
+-   `dict_name` — Name of the dictionary. [String literal](../../sql-reference/syntax.md#syntax-string-literal).
+-   `attr_name` — Name of the column of the dictionary. [String literal](../../sql-reference/syntax.md#syntax-string-literal).
+-   `id_expr` — Key value. [Expression](../../sql-reference/syntax.md#syntax-expressions) returning a [UInt64](../../sql-reference/data-types/int-uint.md) or [Tuple](../../sql-reference/data-types/tuple.md)-type value depending on the dictionary configuration.
+-   `default_value_expr` — Value returned if the dictionary does not contain a row with the `id_expr` key. [Expression](../../sql-reference/syntax.md#syntax-expressions) returning the value in the data type configured for the `attr_name` attribute.
+
+**Returned value**
+
+-   If ClickHouse parses the attribute successfully in the [attribute’s data type](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md#ext_dict_structure-attributes), functions return the value of the dictionary attribute that corresponds to `id_expr`.
+
+-   If there is no requested `id_expr` in the dictionary then:
+
+        - `dictGet[Type]` returns the content of the `<null_value>` element specified for the attribute in the dictionary configuration.
+        - `dictGet[Type]OrDefault` returns the value passed as the `default_value_expr` parameter.
+
+ClickHouse throws an exception if it cannot parse the value of the attribute or the value does not match the attribute data type.
diff --git a/docs/en/reference/sql-reference/functions/files.md b/docs/en/reference/sql-reference/functions/files.md
new file mode 100644
index 00000000000..5bb77016039
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/files.md
@@ -0,0 +1,35 @@
+---
+sidebar_position: 43
+sidebar_label: Files
+---
+
+# Functions for Working with Files {#functions-for-working-with-files}
+
+## file {#file}
+
+Reads file as a String. The file content is not parsed, so any information is read as one string and placed into the specified column.
+
+**Syntax**
+
+``` sql
+file(path)
+```
+
+**Arguments**
+
+-   `path` — The relative path to the file from [user_files_path](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-user_files_path). Path to file support following wildcards: `*`, `?`, `{abc,def}` and `{N..M}` where `N`, `M` — numbers, `'abc', 'def'` — strings.
+
+**Example**
+
+Inserting data from files a.txt and b.txt into a table as strings:
+
+Query:
+
+``` sql
+INSERT INTO table SELECT file('a.txt'), file('b.txt');
+```
+
+**See Also**
+
+-   [user_files_path](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-user_files_path)
+-   [file](../table-functions/file.md)
diff --git a/docs/en/reference/sql-reference/functions/functions-for-nulls.md b/docs/en/reference/sql-reference/functions/functions-for-nulls.md
new file mode 100644
index 00000000000..0ff93357208
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/functions-for-nulls.md
@@ -0,0 +1,311 @@
+---
+sidebar_position: 63
+sidebar_label: Nullable
+---
+
+# Functions for Working with Nullable Values {#functions-for-working-with-nullable-aggregates}
+
+## isNull {#isnull}
+
+Checks whether the argument is [NULL](../../sql-reference/syntax.md#null-literal).
+
+``` sql
+isNull(x)
+```
+
+Alias: `ISNULL`.
+
+**Arguments**
+
+-   `x` — A value with a non-compound data type.
+
+**Returned value**
+
+-   `1` if `x` is `NULL`.
+-   `0` if `x` is not `NULL`.
+
+**Example**
+
+Input table
+
+``` text
+┌─x─┬────y─┐
+│ 1 │ ᴺᵁᴸᴸ │
+│ 2 │    3 │
+└───┴──────┘
+```
+
+Query
+
+``` sql
+SELECT x FROM t_null WHERE isNull(y);
+```
+
+``` text
+┌─x─┐
+│ 1 │
+└───┘
+```
+
+## isNotNull {#isnotnull}
+
+Checks whether the argument is [NULL](../../sql-reference/syntax.md#null-literal).
+
+``` sql
+isNotNull(x)
+```
+
+**Arguments:**
+
+-   `x` — A value with a non-compound data type.
+
+**Returned value**
+
+-   `0` if `x` is `NULL`.
+-   `1` if `x` is not `NULL`.
+
+**Example**
+
+Input table
+
+``` text
+┌─x─┬────y─┐
+│ 1 │ ᴺᵁᴸᴸ │
+│ 2 │    3 │
+└───┴──────┘
+```
+
+Query
+
+``` sql
+SELECT x FROM t_null WHERE isNotNull(y);
+```
+
+``` text
+┌─x─┐
+│ 2 │
+└───┘
+```
+
+## coalesce {#coalesce}
+
+Checks from left to right whether `NULL` arguments were passed and returns the first non-`NULL` argument.
+
+``` sql
+coalesce(x,...)
+```
+
+**Arguments:**
+
+-   Any number of parameters of a non-compound type. All parameters must be compatible by data type.
+
+**Returned values**
+
+-   The first non-`NULL` argument.
+-   `NULL`, if all arguments are `NULL`.
+
+**Example**
+
+Consider a list of contacts that may specify multiple ways to contact a customer.
+
+``` text
+┌─name─────┬─mail─┬─phone─────┬──icq─┐
+│ client 1 │ ᴺᵁᴸᴸ │ 123-45-67 │  123 │
+│ client 2 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ      │ ᴺᵁᴸᴸ │
+└──────────┴──────┴───────────┴──────┘
+```
+
+The `mail` and `phone` fields are of type String, but the `icq` field is `UInt32`, so it needs to be converted to `String`.
+
+Get the first available contact method for the customer from the contact list:
+
+``` sql
+SELECT name, coalesce(mail, phone, CAST(icq,'Nullable(String)')) FROM aBook;
+```
+
+``` text
+┌─name─────┬─coalesce(mail, phone, CAST(icq, 'Nullable(String)'))─┐
+│ client 1 │ 123-45-67                                            │
+│ client 2 │ ᴺᵁᴸᴸ                                                 │
+└──────────┴──────────────────────────────────────────────────────┘
+```
+
+## ifNull {#ifnull}
+
+Returns an alternative value if the main argument is `NULL`.
+
+``` sql
+ifNull(x,alt)
+```
+
+**Arguments:**
+
+-   `x` — The value to check for `NULL`.
+-   `alt` — The value that the function returns if `x` is `NULL`.
+
+**Returned values**
+
+-   The value `x`, if `x` is not `NULL`.
+-   The value `alt`, if `x` is `NULL`.
+
+**Example**
+
+``` sql
+SELECT ifNull('a', 'b');
+```
+
+``` text
+┌─ifNull('a', 'b')─┐
+│ a                │
+└──────────────────┘
+```
+
+``` sql
+SELECT ifNull(NULL, 'b');
+```
+
+``` text
+┌─ifNull(NULL, 'b')─┐
+│ b                 │
+└───────────────────┘
+```
+
+## nullIf {#nullif}
+
+Returns `NULL` if the arguments are equal.
+
+``` sql
+nullIf(x, y)
+```
+
+**Arguments:**
+
+`x`, `y` — Values for comparison. They must be compatible types, or ClickHouse will generate an exception.
+
+**Returned values**
+
+-   `NULL`, if the arguments are equal.
+-   The `x` value, if the arguments are not equal.
+
+**Example**
+
+``` sql
+SELECT nullIf(1, 1);
+```
+
+``` text
+┌─nullIf(1, 1)─┐
+│         ᴺᵁᴸᴸ │
+└──────────────┘
+```
+
+``` sql
+SELECT nullIf(1, 2);
+```
+
+``` text
+┌─nullIf(1, 2)─┐
+│            1 │
+└──────────────┘
+```
+
+## assumeNotNull {#assumenotnull}
+
+Results in an equivalent non-`Nullable` value for a [Nullable](../../sql-reference/data-types/nullable.md) type. In case the original value is `NULL` the result is undetermined. See also `ifNull` and `coalesce` functions.
+
+``` sql
+assumeNotNull(x)
+```
+
+**Arguments:**
+
+-   `x` — The original value.
+
+**Returned values**
+
+-   The original value from the non-`Nullable` type, if it is not `NULL`.
+-   Implementation specific result if the original value was `NULL`.
+
+**Example**
+
+Consider the `t_null` table.
+
+``` sql
+SHOW CREATE TABLE t_null;
+```
+
+``` text
+┌─statement─────────────────────────────────────────────────────────────────┐
+│ CREATE TABLE default.t_null ( x Int8,  y Nullable(Int8)) ENGINE = TinyLog │
+└───────────────────────────────────────────────────────────────────────────┘
+```
+
+``` text
+┌─x─┬────y─┐
+│ 1 │ ᴺᵁᴸᴸ │
+│ 2 │    3 │
+└───┴──────┘
+```
+
+Apply the `assumeNotNull` function to the `y` column.
+
+``` sql
+SELECT assumeNotNull(y) FROM t_null;
+```
+
+``` text
+┌─assumeNotNull(y)─┐
+│                0 │
+│                3 │
+└──────────────────┘
+```
+
+``` sql
+SELECT toTypeName(assumeNotNull(y)) FROM t_null;
+```
+
+``` text
+┌─toTypeName(assumeNotNull(y))─┐
+│ Int8                         │
+│ Int8                         │
+└──────────────────────────────┘
+```
+
+## toNullable {#tonullable}
+
+Converts the argument type to `Nullable`.
+
+``` sql
+toNullable(x)
+```
+
+**Arguments:**
+
+-   `x` — The value of any non-compound type.
+
+**Returned value**
+
+-   The input value with a `Nullable` type.
+
+**Example**
+
+``` sql
+SELECT toTypeName(10);
+```
+
+``` text
+┌─toTypeName(10)─┐
+│ UInt8          │
+└────────────────┘
+```
+
+``` sql
+SELECT toTypeName(toNullable(10));
+```
+
+``` text
+┌─toTypeName(toNullable(10))─┐
+│ Nullable(UInt8)            │
+└────────────────────────────┘
+```
+
diff --git a/docs/en/reference/sql-reference/functions/geo/coordinates.md b/docs/en/reference/sql-reference/functions/geo/coordinates.md
new file mode 100644
index 00000000000..41ba409cbc1
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/geo/coordinates.md
@@ -0,0 +1,147 @@
+---
+sidebar_label: Geographical Coordinates
+sidebar_position: 62
+---
+
+
+# Functions for Working with Geographical Coordinates {#geographical-coordinates}
+
+## greatCircleDistance {#greatcircledistance}
+
+Calculates the distance between two points on the Earth’s surface using [the great-circle formula](https://en.wikipedia.org/wiki/Great-circle_distance).
+
+``` sql
+greatCircleDistance(lon1Deg, lat1Deg, lon2Deg, lat2Deg)
+```
+
+**Input parameters**
+
+-   `lon1Deg` — Longitude of the first point in degrees. Range: `[-180°, 180°]`.
+-   `lat1Deg` — Latitude of the first point in degrees. Range: `[-90°, 90°]`.
+-   `lon2Deg` — Longitude of the second point in degrees. Range: `[-180°, 180°]`.
+-   `lat2Deg` — Latitude of the second point in degrees. Range: `[-90°, 90°]`.
+
+Positive values correspond to North latitude and East longitude, and negative values correspond to South latitude and West longitude.
+
+**Returned value**
+
+The distance between two points on the Earth’s surface, in meters.
+
+Generates an exception when the input parameter values fall outside of the range.
+
+**Example**
+
+``` sql
+SELECT greatCircleDistance(55.755831, 37.617673, -55.755831, -37.617673)
+```
+
+``` text
+┌─greatCircleDistance(55.755831, 37.617673, -55.755831, -37.617673)─┐
+│                                                14132374.194975413 │
+└───────────────────────────────────────────────────────────────────┘
+```
+
+## geoDistance
+
+Similar to `greatCircleDistance` but calculates the distance on WGS-84 ellipsoid instead of sphere. This is more precise approximation of the Earth Geoid.
+The performance is the same as for `greatCircleDistance` (no performance drawback). It is recommended to use `geoDistance` to calculate the distances on Earth.
+
+Technical note: for close enough points we calculate the distance using planar approximation with the metric on the tangent plane at the midpoint of the coordinates.
+
+## greatCircleAngle {#greatcircleangle}
+
+Calculates the central angle between two points on the Earth’s surface using [the great-circle formula](https://en.wikipedia.org/wiki/Great-circle_distance).
+
+``` sql
+greatCircleAngle(lon1Deg, lat1Deg, lon2Deg, lat2Deg)
+```
+
+**Input parameters**
+
+-   `lon1Deg` — Longitude of the first point in degrees.
+-   `lat1Deg` — Latitude of the first point in degrees.
+-   `lon2Deg` — Longitude of the second point in degrees.
+-   `lat2Deg` — Latitude of the second point in degrees.
+
+**Returned value**
+
+The central angle between two points in degrees.
+
+**Example**
+
+``` sql
+SELECT greatCircleAngle(0, 0, 45, 0) AS arc
+```
+
+``` text
+┌─arc─┐
+│  45 │
+└─────┘
+```
+
+## pointInEllipses {#pointinellipses}
+
+Checks whether the point belongs to at least one of the ellipses.
+Coordinates are geometric in the Cartesian coordinate system.
+
+``` sql
+pointInEllipses(x, y, x₀, y₀, a₀, b₀,...,xₙ, yₙ, aₙ, bₙ)
+```
+
+**Input parameters**
+
+-   `x, y` — Coordinates of a point on the plane.
+-   `xᵢ, yᵢ` — Coordinates of the center of the `i`-th ellipsis.
+-   `aᵢ, bᵢ` — Axes of the `i`-th ellipsis in units of x, y coordinates.
+
+The input parameters must be `2+4⋅n`, where `n` is the number of ellipses.
+
+**Returned values**
+
+`1` if the point is inside at least one of the ellipses; `0`if it is not.
+
+**Example**
+
+``` sql
+SELECT pointInEllipses(10., 10., 10., 9.1, 1., 0.9999)
+```
+
+``` text
+┌─pointInEllipses(10., 10., 10., 9.1, 1., 0.9999)─┐
+│                                               1 │
+└─────────────────────────────────────────────────┘
+```
+
+## pointInPolygon {#pointinpolygon}
+
+Checks whether the point belongs to the polygon on the plane.
+
+``` sql
+pointInPolygon((x, y), [(a, b), (c, d) ...], ...)
+```
+
+**Input values**
+
+-   `(x, y)` — Coordinates of a point on the plane. Data type — [Tuple](../../../sql-reference/data-types/tuple.md) — A tuple of two numbers.
+-   `[(a, b), (c, d) ...]` — Polygon vertices. Data type — [Array](../../../sql-reference/data-types/array.md). Each vertex is represented by a pair of coordinates `(a, b)`. Vertices should be specified in a clockwise or counterclockwise order. The minimum number of vertices is 3. The polygon must be constant.
+-   The function also supports polygons with holes (cut out sections). In this case, add polygons that define the cut out sections using additional arguments of the function. The function does not support non-simply-connected polygons.
+
+**Returned values**
+
+`1` if the point is inside the polygon, `0` if it is not.
+If the point is on the polygon boundary, the function may return either 0 or 1.
+
+**Example**
+
+``` sql
+SELECT pointInPolygon((3., 3.), [(6, 0), (8, 4), (5, 8), (0, 2)]) AS res
+```
+
+``` text
+┌─res─┐
+│   1 │
+└─────┘
+```
+
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/functions/geo/coordinates) <!--hide-->
diff --git a/docs/en/reference/sql-reference/functions/geo/geohash.md b/docs/en/reference/sql-reference/functions/geo/geohash.md
new file mode 100644
index 00000000000..e65456d0c40
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/geo/geohash.md
@@ -0,0 +1,114 @@
+---
+sidebar_label: Geohash
+---
+
+# Functions for Working with Geohash {#geohash}
+
+[Geohash](https://en.wikipedia.org/wiki/Geohash) is the geocode system, which subdivides Earth’s surface into buckets of grid shape and encodes each cell into a short string of letters and digits. It is a hierarchical data structure, so the longer is the geohash string, the more precise is the geographic location.
+
+If you need to manually convert geographic coordinates to geohash strings, you can use [geohash.org](http://geohash.org/).
+
+## geohashEncode {#geohashencode}
+
+Encodes latitude and longitude as a [geohash](#geohash)-string.
+
+``` sql
+geohashEncode(longitude, latitude, [precision])
+```
+
+**Input values**
+
+-   longitude - longitude part of the coordinate you want to encode. Floating in range`[-180°, 180°]`
+-   latitude - latitude part of the coordinate you want to encode. Floating in range `[-90°, 90°]`
+-   precision - Optional, length of the resulting encoded string, defaults to `12`. Integer in range `[1, 12]`. Any value less than `1` or greater than `12` is silently converted to `12`.
+
+**Returned values**
+
+-   alphanumeric `String` of encoded coordinate (modified version of the base32-encoding alphabet is used).
+
+**Example**
+
+``` sql
+SELECT geohashEncode(-5.60302734375, 42.593994140625, 0) AS res;
+```
+
+``` text
+┌─res──────────┐
+│ ezs42d000000 │
+└──────────────┘
+```
+
+## geohashDecode {#geohashdecode}
+
+Decodes any [geohash](#geohash)-encoded string into longitude and latitude.
+
+**Input values**
+
+-   encoded string - geohash-encoded string.
+
+**Returned values**
+
+-   (longitude, latitude) - 2-tuple of `Float64` values of longitude and latitude.
+
+**Example**
+
+``` sql
+SELECT geohashDecode('ezs42') AS res;
+```
+
+``` text
+┌─res─────────────────────────────┐
+│ (-5.60302734375,42.60498046875) │
+└─────────────────────────────────┘
+```
+
+## geohashesInBox {#geohashesinbox}
+
+Returns an array of [geohash](#geohash)-encoded strings of given precision that fall inside and intersect boundaries of given box, basically a 2D grid flattened into array.
+
+**Syntax**
+
+``` sql
+geohashesInBox(longitude_min, latitude_min, longitude_max, latitude_max, precision)
+```
+
+**Arguments**
+
+-   `longitude_min` — Minimum longitude. Range: `[-180°, 180°]`. Type: [Float](../../../sql-reference/data-types/float.md).
+-   `latitude_min` — Minimum latitude. Range: `[-90°, 90°]`. Type: [Float](../../../sql-reference/data-types/float.md).
+-   `longitude_max` — Maximum longitude. Range: `[-180°, 180°]`. Type: [Float](../../../sql-reference/data-types/float.md).
+-   `latitude_max` — Maximum latitude. Range: `[-90°, 90°]`. Type: [Float](../../../sql-reference/data-types/float.md).
+-   `precision` — Geohash precision. Range: `[1, 12]`. Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+:::note    
+All coordinate parameters must be of the same type: either `Float32` or `Float64`.
+:::
+
+**Returned values**
+
+-   Array of precision-long strings of geohash-boxes covering provided area, you should not rely on order of items.
+-   `[]` - Empty array if minimum latitude and longitude values aren’t less than corresponding maximum values.
+
+Type: [Array](../../../sql-reference/data-types/array.md)([String](../../../sql-reference/data-types/string.md)).
+
+:::note    
+Function throws an exception if resulting array is over 10’000’000 items long.
+:::
+
+**Example**
+
+Query:
+
+``` sql
+SELECT geohashesInBox(24.48, 40.56, 24.785, 40.81, 4) AS thasos;
+```
+
+Result:
+
+``` text
+┌─thasos──────────────────────────────────────┐
+│ ['sx1q','sx1r','sx32','sx1w','sx1x','sx38'] │
+└─────────────────────────────────────────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/functions/geo/geohash) <!--hide-->
diff --git a/docs/en/reference/sql-reference/functions/geo/h3.md b/docs/en/reference/sql-reference/functions/geo/h3.md
new file mode 100644
index 00000000000..50115dd4d75
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/geo/h3.md
@@ -0,0 +1,1029 @@
+---
+sidebar_label: H3 Indexes
+---
+
+# Functions for Working with H3 Indexes {#h3index}
+
+[H3](https://eng.uber.com/h3/) is a geographical indexing system where Earth’s surface divided into a grid of even hexagonal cells. This system is hierarchical, i. e. each hexagon on the top level ("parent") can be splitted into seven even but smaller ones ("children"), and so on.
+
+The level of the hierarchy is called `resolution` and can receive a value from `0` till `15`, where `0` is the `base` level with the largest and coarsest cells.
+
+A latitude and longitude pair can be transformed to a 64-bit H3 index, identifying a grid cell.
+
+The H3 index is used primarily for bucketing locations and other geospatial manipulations.
+
+The full description of the H3 system is available at [the Uber Engeneering site](https://eng.uber.com/h3/).
+
+## h3IsValid {#h3isvalid}
+
+Verifies whether the number is a valid [H3](#h3index) index.
+
+**Syntax**
+
+``` sql
+h3IsValid(h3index)
+```
+
+**Parameter**
+
+-   `h3index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   1 — The number is a valid H3 index.
+-   0 — The number is not a valid H3 index.
+
+Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3IsValid(630814730351855103) AS h3IsValid;
+```
+
+Result:
+
+``` text
+┌─h3IsValid─┐
+│         1 │
+└───────────┘
+```
+
+## h3GetResolution {#h3getresolution}
+
+Defines the resolution of the given [H3](#h3index) index.
+
+**Syntax**
+
+``` sql
+h3GetResolution(h3index)
+```
+
+**Parameter**
+
+-   `h3index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Index resolution. Range: `[0, 15]`.
+-   If the index is not valid, the function returns a random value. Use [h3IsValid](#h3isvalid) to verify the index.
+
+Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3GetResolution(639821929606596015) AS resolution;
+```
+
+Result:
+
+``` text
+┌─resolution─┐
+│         14 │
+└────────────┘
+```
+
+## h3EdgeAngle {#h3edgeangle}
+
+Calculates the average length of the [H3](#h3index) hexagon edge in grades.
+
+**Syntax**
+
+``` sql
+h3EdgeAngle(resolution)
+```
+
+**Parameter**
+
+-   `resolution` — Index resolution. Type: [UInt8](../../../sql-reference/data-types/int-uint.md). Range: `[0, 15]`.
+
+**Returned values**
+
+-   The average length of the [H3](#h3index) hexagon edge in grades. Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3EdgeAngle(10) AS edgeAngle;
+```
+
+Result:
+
+``` text
+┌───────h3EdgeAngle(10)─┐
+│ 0.0005927224846720883 │
+└───────────────────────┘
+```
+
+## h3EdgeLengthM {#h3edgelengthm}
+
+Calculates the average length of the [H3](#h3index) hexagon edge in meters.
+
+**Syntax**
+
+``` sql
+h3EdgeLengthM(resolution)
+```
+
+**Parameter**
+
+-   `resolution` — Index resolution. Type: [UInt8](../../../sql-reference/data-types/int-uint.md). Range: `[0, 15]`.
+
+**Returned values**
+
+-   The average length of the [H3](#h3index) hexagon edge in meters. Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3EdgeLengthM(15) AS edgeLengthM;
+```
+
+Result:
+
+``` text
+┌─edgeLengthM─┐
+│ 0.509713273 │
+└─────────────┘
+```
+
+## h3EdgeLengthKm {#h3edgelengthkm}
+
+Calculates the average length of the [H3](#h3index) hexagon edge in kilometers.
+
+**Syntax**
+
+``` sql
+h3EdgeLengthKm(resolution)
+```
+
+**Parameter**
+
+-   `resolution` — Index resolution. Type: [UInt8](../../../sql-reference/data-types/int-uint.md). Range: `[0, 15]`.
+
+**Returned values**
+
+-   The average length of the [H3](#h3index) hexagon edge in kilometers. Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3EdgeLengthKm(15) AS edgeLengthKm;
+```
+
+Result:
+
+``` text
+┌─edgeLengthKm─┐
+│  0.000509713 │
+└──────────────┘
+```
+
+## geoToH3 {#geotoh3}
+
+Returns [H3](#h3index) point index `(lon, lat)` with specified resolution.
+
+**Syntax**
+
+``` sql
+geoToH3(lon, lat, resolution)
+```
+
+**Arguments**
+
+-   `lon` — Longitude. Type: [Float64](../../../sql-reference/data-types/float.md).
+-   `lat` — Latitude. Type: [Float64](../../../sql-reference/data-types/float.md).
+-   `resolution` — Index resolution. Range: `[0, 15]`. Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Hexagon index number.
+-   0 in case of error.
+
+Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT geoToH3(37.79506683, 55.71290588, 15) AS h3Index;
+```
+
+Result:
+
+``` text
+┌────────────h3Index─┐
+│ 644325524701193974 │
+└────────────────────┘
+```
+
+## h3ToGeo {#h3togeo}
+
+Returns the centroid longitude and latitude corresponding to the provided [H3](#h3index) index.
+
+**Syntax**
+
+``` sql
+h3ToGeo(h3Index)
+```
+
+**Arguments**
+
+-   `h3Index` — H3 Index. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   A tuple consisting of two values: `tuple(lon,lat)`. `lon` — Longitude. [Float64](../../../sql-reference/data-types/float.md). `lat` — Latitude. [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3ToGeo(644325524701193974) AS coordinates;
+```
+
+Result:
+
+``` text
+┌─coordinates───────────────────────────┐
+│ (37.79506616830252,55.71290243145668) │
+└───────────────────────────────────────┘
+```
+
+## h3ToGeoBoundary {#h3togeoboundary}
+
+Returns array of pairs `(lon, lat)`, which corresponds to the boundary of the provided H3 index.
+
+**Syntax**
+
+``` sql
+h3ToGeoBoundary(h3Index)
+```
+
+**Arguments**
+
+-   `h3Index` — H3 Index. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-    Array of pairs '(lon, lat)'.
+Type: [Array](../../../sql-reference/data-types/array.md)([Float64](../../../sql-reference/data-types/float.md), [Float64](../../../sql-reference/data-types/float.md)).
+
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3ToGeoBoundary(644325524701193974) AS coordinates;
+```
+
+Result:
+
+``` text
+┌─h3ToGeoBoundary(599686042433355775)────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ [(37.2713558667319,-121.91508032705622),(37.353926450852256,-121.8622232890249),(37.42834118609435,-121.92354999630156),(37.42012867767779,-122.03773496427027),(37.33755608435299,-122.090428929044),(37.26319797461824,-122.02910130919001)] │
+└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+## h3kRing {#h3kring}
+
+ Lists all the [H3](#h3index) hexagons in the raduis of `k` from the given hexagon in random order.
+
+**Syntax**
+
+``` sql
+h3kRing(h3index, k)
+```
+
+**Arguments**
+
+-   `h3index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `k` — Radius. Type: [integer](../../../sql-reference/data-types/int-uint.md)
+
+**Returned values**
+
+-   Array of H3 indexes.
+
+Type: [Array](../../../sql-reference/data-types/array.md)([UInt64](../../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT arrayJoin(h3kRing(644325529233966508, 1)) AS h3index;
+```
+
+Result:
+
+``` text
+┌────────────h3index─┐
+│ 644325529233966508 │
+│ 644325529233966497 │
+│ 644325529233966510 │
+│ 644325529233966504 │
+│ 644325529233966509 │
+│ 644325529233966355 │
+│ 644325529233966354 │
+└────────────────────┘
+```
+
+## h3GetBaseCell {#h3getbasecell}
+
+Returns the base cell number of the [H3](#h3index) index.
+
+**Syntax**
+
+``` sql
+h3GetBaseCell(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Hexagon base cell number.
+
+Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3GetBaseCell(612916788725809151) AS basecell;
+```
+
+Result:
+
+``` text
+┌─basecell─┐
+│       12 │
+└──────────┘
+```
+
+## h3HexAreaM2 {#h3hexaream2}
+
+Returns average hexagon area in square meters at the given resolution.
+
+**Syntax**
+
+``` sql
+h3HexAreaM2(resolution)
+```
+
+**Parameter**
+
+-   `resolution` — Index resolution. Range: `[0, 15]`. Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Area in square meters.
+
+Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3HexAreaM2(13) AS area;
+```
+
+Result:
+
+``` text
+┌─area─┐
+│ 43.9 │
+└──────┘
+```
+
+## h3HexAreaKm2 {#h3hexareakm2}
+
+Returns average hexagon area in square kilometers at the given resolution.
+
+**Syntax**
+
+``` sql
+h3HexAreaKm2(resolution)
+```
+
+**Parameter**
+
+-   `resolution` — Index resolution. Range: `[0, 15]`. Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Area in square kilometers.
+
+Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3HexAreaKm2(13) AS area;
+```
+
+Result:
+
+``` text
+┌──────area─┐
+│ 0.0000439 │
+└───────────┘
+```
+
+## h3IndexesAreNeighbors {#h3indexesareneighbors}
+
+Returns whether or not the provided [H3](#h3index) indexes are neighbors.
+
+**Syntax**
+
+``` sql
+h3IndexesAreNeighbors(index1, index2)
+```
+
+**Arguments**
+
+-   `index1` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `index2` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   `1` — Indexes are neighbours.
+-   `0` — Indexes are not neighbours.
+
+Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3IndexesAreNeighbors(617420388351344639, 617420388352655359) AS n;
+```
+
+Result:
+
+``` text
+┌─n─┐
+│ 1 │
+└───┘
+```
+
+## h3ToChildren {#h3tochildren}
+
+Returns an array of child indexes for the given [H3](#h3index) index.
+
+**Syntax**
+
+``` sql
+h3ToChildren(index, resolution)
+```
+
+**Arguments**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `resolution` — Index resolution. Range: `[0, 15]`. Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Array of the child H3-indexes.
+
+Type: [Array](../../../sql-reference/data-types/array.md)([UInt64](../../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3ToChildren(599405990164561919, 6) AS children;
+```
+
+Result:
+
+``` text
+┌─children───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ [603909588852408319,603909588986626047,603909589120843775,603909589255061503,603909589389279231,603909589523496959,603909589657714687] │
+└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+## h3ToParent {#h3toparent}
+
+Returns the parent (coarser) index containing the given [H3](#h3index) index.
+
+**Syntax**
+
+``` sql
+h3ToParent(index, resolution)
+```
+
+**Arguments**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `resolution` — Index resolution. Range: `[0, 15]`. Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Parent H3 index.
+
+Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3ToParent(599405990164561919, 3) AS parent;
+```
+
+Result:
+
+``` text
+┌─────────────parent─┐
+│ 590398848891879423 │
+└────────────────────┘
+```
+
+## h3ToString {#h3tostring}
+
+Converts the `H3Index` representation of the index to the string representation.
+
+``` sql
+h3ToString(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   String representation of the H3 index.
+
+Type: [String](../../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3ToString(617420388352917503) AS h3_string;
+```
+
+Result:
+
+``` text
+┌─h3_string───────┐
+│ 89184926cdbffff │
+└─────────────────┘
+```
+
+## stringToH3 {#stringtoh3}
+
+Converts the string representation to the `H3Index` (UInt64) representation.
+
+**Syntax**
+
+``` sql
+stringToH3(index_str)
+```
+
+**Parameter**
+
+-   `index_str` — String representation of the H3 index. Type: [String](../../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Hexagon index number. Returns 0 on error. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT stringToH3('89184926cc3ffff') AS index;
+```
+
+Result:
+
+``` text
+┌──────────────index─┐
+│ 617420388351344639 │
+└────────────────────┘
+```
+
+## h3GetResolution {#h3getresolution}
+
+Returns the resolution of the [H3](#h3index) index.
+
+**Syntax**
+
+``` sql
+h3GetResolution(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Index resolution. Range: `[0, 15]`. Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3GetResolution(617420388352917503) AS res;
+```
+
+Result:
+
+``` text
+┌─res─┐
+│   9 │
+└─────┘
+```
+
+## h3IsResClassIII {#h3isresclassIII}
+
+Returns whether [H3](#h3index) index has a resolution with Class III orientation.
+
+**Syntax**
+
+``` sql
+h3IsResClassIII(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   `1` — Index has a resolution with Class III orientation.
+-   `0` — Index doesn't have a resolution with Class III orientation.
+
+Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3IsResClassIII(617420388352917503) AS res;
+```
+
+Result:
+
+``` text
+┌─res─┐
+│   1 │
+└─────┘
+```
+
+## h3IsPentagon {#h3ispentagon}
+
+Returns whether this [H3](#h3index) index represents a pentagonal cell.
+
+**Syntax**
+
+``` sql
+h3IsPentagon(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   `1` — Index represents a pentagonal cell.
+-   `0` — Index doesn't represent a pentagonal cell.
+
+Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3IsPentagon(644721767722457330) AS pentagon;
+```
+
+Result:
+
+``` text
+┌─pentagon─┐
+│        0 │
+└──────────┘
+```
+
+## h3GetFaces {#h3getfaces}
+
+Returns icosahedron faces intersected by a given [H3](#h3index) index.
+
+**Syntax**
+
+``` sql
+h3GetFaces(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Array containing icosahedron faces intersected by a given H3 index.
+
+Type: [Array](../../../sql-reference/data-types/array.md)([UInt64](../../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3GetFaces(599686042433355775) AS faces;
+```
+
+Result:
+
+``` text
+┌─faces─┐
+│ [7]   │
+└───────┘
+```
+
+## h3CellAreaM2 {#h3cellaream2}
+
+Returns the exact area of a specific cell in square meters corresponding to the given input H3 index.
+
+**Syntax**
+
+``` sql
+h3CellAreaM2(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Cell area in square meters.
+
+Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3CellAreaM2(579205133326352383) AS area;
+```
+
+Result:
+
+``` text
+┌───────────────area─┐
+│ 4106166334463.9233 │
+└────────────────────┘
+```
+
+## h3CellAreaRads2 {#h3cellarearads2}
+
+Returns the exact area of a specific cell in square radians corresponding to the given input H3 index.
+
+**Syntax**
+
+``` sql
+h3CellAreaRads2(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Cell area in square radians.
+
+Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3CellAreaRads2(579205133326352383) AS area;
+```
+
+Result:
+
+``` text
+┌────────────────area─┐
+│ 0.10116268528089567 │
+└─────────────────────┘
+```
+
+## h3ToCenterChild {#h3tocenterchild}
+
+Returns the center child (finer) [H3](#h3index) index contained by given [H3](#h3index) at the given resolution.
+
+**Syntax**
+
+``` sql
+h3ToCenterChild(index, resolution)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `resolution` — Index resolution. Range: `[0, 15]`. Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+- [H3](#h3index) index of the center child contained by given [H3](#h3index) at the given resolution.
+
+Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3ToCenterChild(577023702256844799,1) AS centerToChild;
+```
+
+Result:
+
+``` text
+┌──────centerToChild─┐
+│ 581496515558637567 │
+└────────────────────┘
+```
+
+## h3ExactEdgeLengthM {#h3exactedgelengthm}
+
+Returns the exact edge length of the unidirectional edge represented by the input h3 index in meters.
+
+**Syntax**
+
+``` sql
+h3ExactEdgeLengthM(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-  Exact edge length in meters.
+
+Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3ExactEdgeLengthM(1310277011704381439) AS exactEdgeLengthM;;
+```
+
+Result:
+
+``` text
+┌───exactEdgeLengthM─┐
+│ 195449.63163407316 │
+└────────────────────┘
+```
+
+## h3ExactEdgeLengthKm {#h3exactedgelengthkm}
+
+Returns the exact edge length of the unidirectional edge represented by the input h3 index in kilometers.
+
+**Syntax**
+
+``` sql
+h3ExactEdgeLengthKm(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-  Exact edge length in kilometers.
+
+Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3ExactEdgeLengthKm(1310277011704381439) AS exactEdgeLengthKm;;
+```
+
+Result:
+
+``` text
+┌──exactEdgeLengthKm─┐
+│ 195.44963163407317 │
+└────────────────────┘
+```
+
+## h3ExactEdgeLengthRads {#h3exactedgelengthrads}
+
+Returns the exact edge length of the unidirectional edge represented by the input h3 index in radians.
+
+**Syntax**
+
+``` sql
+h3ExactEdgeLengthRads(index)
+```
+
+**Parameter**
+
+-   `index` — Hexagon index number. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-  Exact edge length in radians.
+
+Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3ExactEdgeLengthRads(1310277011704381439) AS exactEdgeLengthRads;;
+```
+
+Result:
+
+``` text
+┌──exactEdgeLengthRads─┐
+│ 0.030677980118976447 │
+└──────────────────────┘
+```
+
+## h3NumHexagons {#h3numhexagons}
+
+Returns the number of unique H3 indices at the given resolution.
+
+**Syntax**
+
+``` sql
+h3NumHexagons(resolution)
+```
+
+**Parameter**
+
+-   `resolution` — Index resolution. Range: `[0, 15]`. Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-  Number of H3 indices.
+
+Type: [Int64](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT h3NumHexagons(3) AS numHexagons;
+```
+
+Result:
+
+``` text
+┌─numHexagons─┐
+│       41162 │
+└─────────────┘
+```
+[Original article](https://clickhouse.com/docs/en/sql-reference/functions/geo/h3) <!--hide-->
diff --git a/docs/en/reference/sql-reference/functions/geo/index.md b/docs/en/reference/sql-reference/functions/geo/index.md
new file mode 100644
index 00000000000..f76c3a3f731
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/geo/index.md
@@ -0,0 +1,8 @@
+---
+sidebar_label: Geo
+sidebar_position: 62
+---
+
+# Geo Functions
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/functions/geo/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/functions/geo/s2.md b/docs/en/reference/sql-reference/functions/geo/s2.md
new file mode 100644
index 00000000000..c3d95d2f0a9
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/geo/s2.md
@@ -0,0 +1,376 @@
+--- 
+sidebar_label: S2 Geometry
+---
+
+# Functions for Working with S2 Index {#s2index}
+
+[S2](https://s2geometry.io/) is a geographical indexing system where all geographical data is represented on a three-dimensional sphere (similar to a globe).
+
+In the S2 library points are represented as the S2 Index - a specific number which encodes internally a point on the surface of a unit sphere, unlike traditional (latitude, longitude) pairs. To get the S2 point index for a given point specified in the format (latitude, longitude) use the [geoToS2](#geotos2) function. Also, you can use the [s2ToGeo](#s2togeo) function for getting geographical coordinates corresponding to the specified S2 point index.
+
+## geoToS2 {#geotos2}
+
+Returns [S2](#s2index) point index corresponding to the provided coordinates `(longitude, latitude)`.
+
+**Syntax**
+
+``` sql
+geoToS2(lon, lat)
+```
+
+**Arguments**
+
+-   `lon` — Longitude. [Float64](../../../sql-reference/data-types/float.md).
+-   `lat` — Latitude. [Float64](../../../sql-reference/data-types/float.md).
+
+**Returned values**
+
+-   S2 point index.
+
+Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT geoToS2(37.79506683, 55.71290588) AS s2Index;
+```
+
+Result:
+
+``` text
+┌─────────────s2Index─┐
+│ 4704772434919038107 │
+└─────────────────────┘
+```
+
+## s2ToGeo {#s2togeo}
+
+Returns geo coordinates `(longitude, latitude)` corresponding to the provided [S2](#s2index) point index.
+
+**Syntax**
+
+``` sql
+s2ToGeo(s2index)
+```
+
+**Arguments**
+
+-   `s2index` — S2 Index. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   A tuple consisting of two values: `tuple(lon,lat)`.
+
+Type: `lon` — [Float64](../../../sql-reference/data-types/float.md). `lat` — [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT s2ToGeo(4704772434919038107) AS s2Coodrinates;
+```
+
+Result:
+
+``` text
+┌─s2Coodrinates────────────────────────┐
+│ (37.79506681471008,55.7129059052841) │
+└──────────────────────────────────────┘
+```
+
+## s2GetNeighbors {#s2getneighbors}
+
+Returns S2 neighbor indixes corresponding to the provided [S2](#s2index). Each cell in the S2 system is a quadrilateral bounded by four geodesics. So, each cell has 4 neighbors. 
+
+**Syntax**
+
+``` sql
+s2GetNeighbors(s2index)
+```
+
+**Arguments**
+
+-   `s2index` — S2 Index. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   An array consisting of 4 neighbor indexes: `array[s2index1, s2index3, s2index2, s2index4]`.
+
+Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT s2GetNeighbors(5074766849661468672) AS s2Neighbors;
+```
+
+Result:
+
+``` text
+┌─s2Neighbors───────────────────────────────────────────────────────────────────────┐
+│ [5074766987100422144,5074766712222515200,5074767536856236032,5074767261978329088] │
+└───────────────────────────────────────────────────────────────────────────────────┘
+```
+
+## s2CellsIntersect {#s2cellsintersect}
+
+Determines if the two provided [S2](#s2index) cells intersect or not.
+
+**Syntax**
+
+``` sql
+s2CellsIntersect(s2index1, s2index2)
+```
+
+**Arguments**
+
+-   `siIndex1`, `s2index2` — S2 Index. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   1 — If the cells intersect.
+-   0 — If the cells don't intersect.
+
+Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT s2CellsIntersect(9926595209846587392, 9926594385212866560) AS intersect;
+```
+
+Result:
+
+``` text
+┌─intersect─┐
+│         1 │
+└───────────┘
+```
+
+## s2CapContains {#s2capcontains}
+
+Determines if a cap contains a S2 point. A cap represents a part of the sphere that has been cut off by a plane. It is defined by a point on a sphere and a radius in degrees.
+
+**Syntax**
+
+``` sql
+s2CapContains(center, degrees, point)
+```
+
+**Arguments**
+
+-   `center` — S2 point index corresponding to the cap. [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `degrees` — Radius of the cap in degrees. [Float64](../../../sql-reference/data-types/float.md).
+-   `point` — S2 point index. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   1 — If the cap contains the S2 point index.
+-   0 — If the cap doesn't contain the S2 point index.
+
+Type: [UInt8](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT s2CapContains(1157339245694594829, 1.0, 1157347770437378819) AS capContains;
+```
+
+Result:
+
+``` text
+┌─capContains─┐
+│           1 │
+└─────────────┘
+```
+
+## s2CapUnion {#s2capunion}
+
+Determines the smallest cap that contains the given two input caps. A cap represents a portion of the sphere that has been cut off by a plane. It is defined by a point on a sphere and a radius in degrees.
+
+**Syntax**
+
+``` sql
+s2CapUnion(center1, radius1, center2, radius2)
+```
+
+**Arguments**
+
+-   `center1`, `center2` — S2 point indixes corresponding to the two input caps. [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `radius1`, `radius2` — Radius of the two input caps in degrees. [Float64](../../../sql-reference/data-types/float.md).
+
+**Returned values**
+
+-   `center` — S2 point index corresponding the center of the smallest cap containing the two input caps. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `radius` — Radius of the smallest cap containing the two input caps. Type: [Float64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT s2CapUnion(3814912406305146967, 1.0, 1157347770437378819, 1.0) AS capUnion;
+```
+
+Result:
+
+``` text
+┌─capUnion───────────────────────────────┐
+│ (4534655147792050737,60.2088283994957) │
+└────────────────────────────────────────┘
+```
+
+## s2RectAdd {#s2rectadd}
+
+Increases the size of the bounding rectangle to include the given S2 point. In the S2 system, a rectangle is represented by a type of S2Region called a `S2LatLngRect` that represents a rectangle in latitude-longitude space.
+
+**Syntax**
+
+``` sql
+s2RectAdd(s2pointLow, s2pointHigh, s2Point)
+```
+
+**Arguments**
+
+-   `s2PointLow` — Low S2 point index corresponding to the rectangle. [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `s2PointHigh` — High S2 point index corresponding to the rectangle. [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `s2Point` — Target S2 point index that the bound rectangle should be grown to include. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   `s2PointLow` — Low S2 cell id corresponding to the grown rectangle. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `s2PointHigh` — Hight S2 cell id corresponding to the grown rectangle. Type: [UInt64](../../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT s2RectAdd(5178914411069187297, 5177056748191934217, 5179056748191934217) AS rectAdd;
+```
+
+Result:
+
+``` text
+┌─rectAdd───────────────────────────────────┐
+│ (5179062030687166815,5177056748191934217) │
+└───────────────────────────────────────────┘
+```
+
+## s2RectContains {#s2rectcontains}
+
+Determines if a given rectangle contains a S2 point. In the S2 system, a rectangle is represented by a type of S2Region called a `S2LatLngRect` that represents a rectangle in latitude-longitude space.
+
+**Syntax**
+
+``` sql
+s2RectContains(s2PointLow, s2PointHi, s2Point)
+```
+
+**Arguments**
+
+-   `s2PointLow` — Low S2 point index corresponding to the rectangle. [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `s2PointHigh` — High S2 point index corresponding to the rectangle. [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `s2Point` — Target S2 point index. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   1 — If the rectangle contains the given S2 point.
+-   0 — If the rectangle doesn't contain the given S2 point.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT s2RectContains(5179062030687166815, 5177056748191934217, 5177914411069187297) AS rectContains;
+```
+
+Result:
+
+``` text
+┌─rectContains─┐
+│            0 │
+└──────────────┘
+```
+
+## s2RectUinion {#s2rectunion}
+
+Returns the smallest rectangle containing the union of this rectangle and the given rectangle. In the S2 system, a rectangle is represented by a type of S2Region called a `S2LatLngRect` that represents a rectangle in latitude-longitude space.
+
+**Syntax**
+
+``` sql
+s2RectUnion(s2Rect1PointLow, s2Rect1PointHi, s2Rect2PointLow, s2Rect2PointHi)
+```
+
+**Arguments**
+
+-   `s2Rect1PointLow`, `s2Rect1PointHi` — Low and High S2 point indexes corresponding to the first rectangle. [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `s2Rect2PointLow`, `s2Rect2PointHi` — Low and High S2 point indexes corresponding to the second rectangle. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   `s2UnionRect2PointLow` — Low S2 cell id corresponding to the union rectangle. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `s2UnionRect2PointHi` — High S2 cell id corresponding to the union rectangle. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT s2RectUnion(5178914411069187297, 5177056748191934217, 5179062030687166815, 5177056748191934217) AS rectUnion;
+```
+
+Result:
+
+``` text
+┌─rectUnion─────────────────────────────────┐
+│ (5179062030687166815,5177056748191934217) │
+└───────────────────────────────────────────┘
+```
+
+## s2RectIntersection {#s2rectintersection}
+
+Returns the smallest rectangle containing the intersection of this rectangle and the given rectangle. In the S2 system, a rectangle is represented by a type of S2Region called a `S2LatLngRect` that represents a rectangle in latitude-longitude space.
+
+**Syntax**
+
+``` sql
+s2RectIntersection(s2Rect1PointLow, s2Rect1PointHi, s2Rect2PointLow, s2Rect2PointHi)
+```
+
+**Arguments**
+
+-   `s2Rect1PointLow`, `s2Rect1PointHi` — Low and High S2 point indexes corresponding to the first rectangle. [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `s2Rect2PointLow`, `s2Rect2PointHi` — Low and High S2 point indexes corresponding to the second rectangle. [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   `s2UnionRect2PointLow` — Low S2 cell id corresponding to the rectangle containing the intersection of the given rectangles. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+-   `s2UnionRect2PointHi` — High S2 cell id corresponding to the rectangle containing the intersection of the given rectangles. Type: [UInt64](../../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT s2RectIntersection(5178914411069187297, 5177056748191934217, 5179062030687166815, 5177056748191934217) AS rectIntersection;
+```
+
+Result:
+
+``` text
+┌─rectIntersection──────────────────────────┐
+│ (5178914411069187297,5177056748191934217) │
+└───────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/hash-functions.md b/docs/en/reference/sql-reference/functions/hash-functions.md
new file mode 100644
index 00000000000..e4b1fdd3bbb
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/hash-functions.md
@@ -0,0 +1,1496 @@
+---
+sidebar_position: 50
+sidebar_label: Hash
+---
+
+# Hash Functions {#hash-functions}
+
+Hash functions can be used for the deterministic pseudo-random shuffling of elements.
+
+Simhash is a hash function, which returns close hash values for close (similar) arguments.
+
+## halfMD5 {#hash-functions-halfmd5}
+
+[Interprets](../../sql-reference/functions/type-conversion-functions.md#type_conversion_functions-reinterpretAsString) all the input parameters as strings and calculates the [MD5](https://en.wikipedia.org/wiki/MD5) hash value for each of them. Then combines hashes, takes the first 8 bytes of the hash of the resulting string, and interprets them as `UInt64` in big-endian byte order.
+
+``` sql
+halfMD5(par1, ...)
+```
+
+The function is relatively slow (5 million short strings per second per processor core).
+Consider using the [sipHash64](#hash_functions-siphash64) function instead.
+
+**Arguments**
+
+The function takes a variable number of input parameters. Arguments can be any of the [supported data types](../../sql-reference/data-types/index.md).
+
+**Returned Value**
+
+A [UInt64](../../sql-reference/data-types/int-uint.md) data type hash value.
+
+**Example**
+
+``` sql
+SELECT halfMD5(array('e','x','a'), 'mple', 10, toDateTime('2019-06-15 23:00:00')) AS halfMD5hash, toTypeName(halfMD5hash) AS type;
+```
+
+``` text
+┌────────halfMD5hash─┬─type───┐
+│ 186182704141653334 │ UInt64 │
+└────────────────────┴────────┘
+```
+
+## MD4 {#hash_functions-md4}
+
+Calculates the MD4 from a string and returns the resulting set of bytes as FixedString(16).
+
+## MD5 {#hash_functions-md5}
+
+Calculates the MD5 from a string and returns the resulting set of bytes as FixedString(16).
+If you do not need MD5 in particular, but you need a decent cryptographic 128-bit hash, use the ‘sipHash128’ function instead.
+If you want to get the same result as output by the md5sum utility, use lower(hex(MD5(s))).
+
+## sipHash64 {#hash_functions-siphash64}
+
+Produces a 64-bit [SipHash](https://131002.net/siphash/) hash value.
+
+``` sql
+sipHash64(par1,...)
+```
+
+This is a cryptographic hash function. It works at least three times faster than the [MD5](#hash_functions-md5) function.
+
+Function [interprets](../../sql-reference/functions/type-conversion-functions.md#type_conversion_functions-reinterpretAsString) all the input parameters as strings and calculates the hash value for each of them. Then combines hashes by the following algorithm:
+
+1.  After hashing all the input parameters, the function gets the array of hashes.
+2.  Function takes the first and the second elements and calculates a hash for the array of them.
+3.  Then the function takes the hash value, calculated at the previous step, and the third element of the initial hash array, and calculates a hash for the array of them.
+4.  The previous step is repeated for all the remaining elements of the initial hash array.
+
+**Arguments**
+
+The function takes a variable number of input parameters. Arguments can be any of the [supported data types](../../sql-reference/data-types/index.md).
+
+**Returned Value**
+
+A [UInt64](../../sql-reference/data-types/int-uint.md) data type hash value.
+
+**Example**
+
+``` sql
+SELECT sipHash64(array('e','x','a'), 'mple', 10, toDateTime('2019-06-15 23:00:00')) AS SipHash, toTypeName(SipHash) AS type;
+```
+
+``` text
+┌──────────────SipHash─┬─type───┐
+│ 13726873534472839665 │ UInt64 │
+└──────────────────────┴────────┘
+```
+
+## sipHash128 {#hash_functions-siphash128}
+
+Produces a 128-bit [SipHash](https://131002.net/siphash/) hash value. Differs from [sipHash64](#hash_functions-siphash64) in that the final xor-folding state is done up to 128 bits.
+
+**Syntax**
+
+``` sql
+sipHash128(par1,...)
+```
+
+**Arguments**
+
+The function takes a variable number of input parameters. Arguments can be any of the [supported data types](../../sql-reference/data-types/index.md).
+
+**Returned value**
+
+A 128-bit `SipHash` hash value.
+
+Type: [FixedString(16)](../../sql-reference/data-types/fixedstring.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT hex(sipHash128('foo', '\x01', 3));
+```
+
+Result:
+
+``` text
+┌─hex(sipHash128('foo', '', 3))────┐
+│ 9DE516A64A414D4B1B609415E4523F24 │
+└──────────────────────────────────┘
+```
+
+## cityHash64 {#cityhash64}
+
+Produces a 64-bit [CityHash](https://github.com/google/cityhash) hash value.
+
+``` sql
+cityHash64(par1,...)
+```
+
+This is a fast non-cryptographic hash function. It uses the CityHash algorithm for string parameters and implementation-specific fast non-cryptographic hash function for parameters with other data types. The function uses the CityHash combinator to get the final results.
+
+**Arguments**
+
+The function takes a variable number of input parameters. Arguments can be any of the [supported data types](../../sql-reference/data-types/index.md).
+
+**Returned Value**
+
+A [UInt64](../../sql-reference/data-types/int-uint.md) data type hash value.
+
+**Examples**
+
+Call example:
+
+``` sql
+SELECT cityHash64(array('e','x','a'), 'mple', 10, toDateTime('2019-06-15 23:00:00')) AS CityHash, toTypeName(CityHash) AS type;
+```
+
+``` text
+┌─────────────CityHash─┬─type───┐
+│ 12072650598913549138 │ UInt64 │
+└──────────────────────┴────────┘
+```
+
+The following example shows how to compute the checksum of the entire table with accuracy up to the row order:
+
+``` sql
+SELECT groupBitXor(cityHash64(*)) FROM table
+```
+
+## intHash32 {#inthash32}
+
+Calculates a 32-bit hash code from any type of integer.
+This is a relatively fast non-cryptographic hash function of average quality for numbers.
+
+## intHash64 {#inthash64}
+
+Calculates a 64-bit hash code from any type of integer.
+It works faster than intHash32. Average quality.
+
+## SHA1, SHA224, SHA256, SHA512 {#sha}
+
+Calculates SHA-1, SHA-224, SHA-256, SHA-512 hash from a string and returns the resulting set of bytes as [FixedString](../data-types/fixedstring.md).
+
+**Syntax**
+
+``` sql
+SHA1('s')
+...
+SHA512('s')
+```
+
+The function works fairly slowly (SHA-1 processes about 5 million short strings per second per processor core, while SHA-224 and SHA-256 process about 2.2 million).
+We recommend using this function only in cases when you need a specific hash function and you can’t select it.
+Even in these cases, we recommend applying the function offline and pre-calculating values when inserting them into the table, instead of applying it in `SELECT` queries.
+
+**Arguments**
+
+-   `s` — Input string for SHA hash calculation. [String](../data-types/string.md).
+
+**Returned value**
+
+-   SHA hash as a hex-unencoded FixedString. SHA-1 returns as FixedString(20), SHA-224 as FixedString(28), SHA-256 — FixedString(32), SHA-512 — FixedString(64).
+
+Type: [FixedString](../data-types/fixedstring.md).
+
+**Example**
+
+Use the [hex](../functions/encoding-functions.md#hex) function to represent the result as a hex-encoded string.
+
+Query:
+
+``` sql
+SELECT hex(SHA1('abc'));
+```
+
+Result:
+
+``` text
+┌─hex(SHA1('abc'))─────────────────────────┐
+│ A9993E364706816ABA3E25717850C26C9CD0D89D │
+└──────────────────────────────────────────┘
+```
+
+## URLHash(url\[, N\]) {#urlhashurl-n}
+
+A fast, decent-quality non-cryptographic hash function for a string obtained from a URL using some type of normalization.
+`URLHash(s)` – Calculates a hash from a string without one of the trailing symbols `/`,`?` or `#` at the end, if present.
+`URLHash(s, N)` – Calculates a hash from a string up to the N level in the URL hierarchy, without one of the trailing symbols `/`,`?` or `#` at the end, if present.
+Levels are the same as in URLHierarchy. 
+
+## farmFingerprint64 {#farmfingerprint64}
+
+## farmHash64 {#farmhash64}
+
+Produces a 64-bit [FarmHash](https://github.com/google/farmhash) or Fingerprint value. `farmFingerprint64` is preferred for a stable and portable value.
+
+``` sql
+farmFingerprint64(par1, ...)
+farmHash64(par1, ...)
+```
+
+These functions use the `Fingerprint64` and `Hash64` methods respectively from all [available methods](https://github.com/google/farmhash/blob/master/src/farmhash.h).
+
+**Arguments**
+
+The function takes a variable number of input parameters. Arguments can be any of the [supported data types](../../sql-reference/data-types/index.md).
+
+**Returned Value**
+
+A [UInt64](../../sql-reference/data-types/int-uint.md) data type hash value.
+
+**Example**
+
+``` sql
+SELECT farmHash64(array('e','x','a'), 'mple', 10, toDateTime('2019-06-15 23:00:00')) AS FarmHash, toTypeName(FarmHash) AS type;
+```
+
+``` text
+┌─────────────FarmHash─┬─type───┐
+│ 17790458267262532859 │ UInt64 │
+└──────────────────────┴────────┘
+```
+
+## javaHash {#hash_functions-javahash}
+
+Calculates [JavaHash](http://hg.openjdk.java.net/jdk8u/jdk8u/jdk/file/478a4add975b/src/share/classes/java/lang/String.java#l1452) from a string. This hash function is neither fast nor having a good quality. The only reason to use it is when this algorithm is already used in another system and you have to calculate exactly the same result.
+
+**Syntax**
+
+``` sql
+SELECT javaHash('')
+```
+
+**Returned value**
+
+A `Int32` data type hash value.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT javaHash('Hello, world!');
+```
+
+Result:
+
+``` text
+┌─javaHash('Hello, world!')─┐
+│               -1880044555 │
+└───────────────────────────┘
+```
+
+## javaHashUTF16LE {#javahashutf16le}
+
+Calculates [JavaHash](http://hg.openjdk.java.net/jdk8u/jdk8u/jdk/file/478a4add975b/src/share/classes/java/lang/String.java#l1452) from a string, assuming it contains bytes representing a string in UTF-16LE encoding.
+
+**Syntax**
+
+``` sql
+javaHashUTF16LE(stringUtf16le)
+```
+
+**Arguments**
+
+-   `stringUtf16le` — a string in UTF-16LE encoding.
+
+**Returned value**
+
+A `Int32` data type hash value.
+
+**Example**
+
+Correct query with UTF-16LE encoded string.
+
+Query:
+
+``` sql
+SELECT javaHashUTF16LE(convertCharset('test', 'utf-8', 'utf-16le'));
+```
+
+Result:
+
+``` text
+┌─javaHashUTF16LE(convertCharset('test', 'utf-8', 'utf-16le'))─┐
+│                                                      3556498 │
+└──────────────────────────────────────────────────────────────┘
+```
+
+## hiveHash {#hash-functions-hivehash}
+
+Calculates `HiveHash` from a string.
+
+``` sql
+SELECT hiveHash('')
+```
+
+This is just [JavaHash](#hash_functions-javahash) with zeroed out sign bit. This function is used in [Apache Hive](https://en.wikipedia.org/wiki/Apache_Hive) for versions before 3.0. This hash function is neither fast nor having a good quality. The only reason to use it is when this algorithm is already used in another system and you have to calculate exactly the same result.
+
+**Returned value**
+
+A `Int32` data type hash value.
+
+Type: `hiveHash`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT hiveHash('Hello, world!');
+```
+
+Result:
+
+``` text
+┌─hiveHash('Hello, world!')─┐
+│                 267439093 │
+└───────────────────────────┘
+```
+
+## metroHash64 {#metrohash64}
+
+Produces a 64-bit [MetroHash](http://www.jandrewrogers.com/2015/05/27/metrohash/) hash value.
+
+``` sql
+metroHash64(par1, ...)
+```
+
+**Arguments**
+
+The function takes a variable number of input parameters. Arguments can be any of the [supported data types](../../sql-reference/data-types/index.md).
+
+**Returned Value**
+
+A [UInt64](../../sql-reference/data-types/int-uint.md) data type hash value.
+
+**Example**
+
+``` sql
+SELECT metroHash64(array('e','x','a'), 'mple', 10, toDateTime('2019-06-15 23:00:00')) AS MetroHash, toTypeName(MetroHash) AS type;
+```
+
+``` text
+┌────────────MetroHash─┬─type───┐
+│ 14235658766382344533 │ UInt64 │
+└──────────────────────┴────────┘
+```
+
+## jumpConsistentHash {#jumpconsistenthash}
+
+Calculates JumpConsistentHash form a UInt64.
+Accepts two arguments: a UInt64-type key and the number of buckets. Returns Int32.
+For more information, see the link: [JumpConsistentHash](https://arxiv.org/pdf/1406.2294.pdf)
+
+## murmurHash2_32, murmurHash2_64 {#murmurhash2-32-murmurhash2-64}
+
+Produces a [MurmurHash2](https://github.com/aappleby/smhasher) hash value.
+
+``` sql
+murmurHash2_32(par1, ...)
+murmurHash2_64(par1, ...)
+```
+
+**Arguments**
+
+Both functions take a variable number of input parameters. Arguments can be any of the [supported data types](../../sql-reference/data-types/index.md).
+
+**Returned Value**
+
+-   The `murmurHash2_32` function returns hash value having the [UInt32](../../sql-reference/data-types/int-uint.md) data type.
+-   The `murmurHash2_64` function returns hash value having the [UInt64](../../sql-reference/data-types/int-uint.md) data type.
+
+**Example**
+
+``` sql
+SELECT murmurHash2_64(array('e','x','a'), 'mple', 10, toDateTime('2019-06-15 23:00:00')) AS MurmurHash2, toTypeName(MurmurHash2) AS type;
+```
+
+``` text
+┌──────────MurmurHash2─┬─type───┐
+│ 11832096901709403633 │ UInt64 │
+└──────────────────────┴────────┘
+```
+
+## gccMurmurHash {#gccmurmurhash}
+
+Calculates a 64-bit [MurmurHash2](https://github.com/aappleby/smhasher) hash value using the same hash seed as [gcc](https://github.com/gcc-mirror/gcc/blob/41d6b10e96a1de98e90a7c0378437c3255814b16/libstdc%2B%2B-v3/include/bits/functional_hash.h#L191). It is portable between CLang and GCC builds.
+
+**Syntax**
+
+``` sql
+gccMurmurHash(par1, ...)
+```
+
+**Arguments**
+
+-   `par1, ...` — A variable number of parameters that can be any of the [supported data types](../../sql-reference/data-types/index.md#data_types).
+
+**Returned value**
+
+-   Calculated hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT
+    gccMurmurHash(1, 2, 3) AS res1,
+    gccMurmurHash(('a', [1, 2, 3], 4, (4, ['foo', 'bar'], 1, (1, 2)))) AS res2
+```
+
+Result:
+
+``` text
+┌─────────────────res1─┬────────────────res2─┐
+│ 12384823029245979431 │ 1188926775431157506 │
+└──────────────────────┴─────────────────────┘
+```
+
+## murmurHash3_32, murmurHash3_64 {#murmurhash3-32-murmurhash3-64}
+
+Produces a [MurmurHash3](https://github.com/aappleby/smhasher) hash value.
+
+``` sql
+murmurHash3_32(par1, ...)
+murmurHash3_64(par1, ...)
+```
+
+**Arguments**
+
+Both functions take a variable number of input parameters. Arguments can be any of the [supported data types](../../sql-reference/data-types/index.md).
+
+**Returned Value**
+
+-   The `murmurHash3_32` function returns a [UInt32](../../sql-reference/data-types/int-uint.md) data type hash value.
+-   The `murmurHash3_64` function returns a [UInt64](../../sql-reference/data-types/int-uint.md) data type hash value.
+
+**Example**
+
+``` sql
+SELECT murmurHash3_32(array('e','x','a'), 'mple', 10, toDateTime('2019-06-15 23:00:00')) AS MurmurHash3, toTypeName(MurmurHash3) AS type;
+```
+
+``` text
+┌─MurmurHash3─┬─type───┐
+│     2152717 │ UInt32 │
+└─────────────┴────────┘
+```
+
+## murmurHash3_128 {#murmurhash3-128}
+
+Produces a 128-bit [MurmurHash3](https://github.com/aappleby/smhasher) hash value.
+
+**Syntax**
+
+``` sql
+murmurHash3_128(expr)
+```
+
+**Arguments**
+
+-   `expr` — A list of [expressions](../../sql-reference/syntax.md#syntax-expressions). [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+A 128-bit `MurmurHash3` hash value.
+
+Type: [FixedString(16)](../../sql-reference/data-types/fixedstring.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT hex(murmurHash3_128('foo', 'foo', 'foo'));
+```
+
+Result:
+
+``` text
+┌─hex(murmurHash3_128('foo', 'foo', 'foo'))─┐
+│ F8F7AD9B6CD4CF117A71E277E2EC2931          │
+└───────────────────────────────────────────┘
+```
+
+## xxHash32, xxHash64 {#hash-functions-xxhash32}
+
+Calculates `xxHash` from a string. It is proposed in two flavors, 32 and 64 bits.
+
+``` sql
+SELECT xxHash32('')
+
+OR
+
+SELECT xxHash64('')
+```
+
+**Returned value**
+
+A `Uint32` or `Uint64` data type hash value.
+
+Type: `xxHash`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT xxHash32('Hello, world!');
+```
+
+Result:
+
+``` text
+┌─xxHash32('Hello, world!')─┐
+│                 834093149 │
+└───────────────────────────┘
+```
+
+**See Also**
+
+-   [xxHash](http://cyan4973.github.io/xxHash/).
+
+## ngramSimHash {#ngramsimhash}
+
+Splits a ASCII string into n-grams of `ngramsize` symbols and returns the n-gram `simhash`. Is case sensitive.
+
+Can be used for detection of semi-duplicate strings with [bitHammingDistance](../../sql-reference/functions/bit-functions.md#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
+
+**Syntax**
+
+``` sql
+ngramSimHash(string[, ngramsize])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramSimHash('ClickHouse') AS Hash;
+```
+
+Result:
+
+``` text
+┌───────Hash─┐
+│ 1627567969 │
+└────────────┘
+```
+
+## ngramSimHashCaseInsensitive {#ngramsimhashcaseinsensitive}
+
+Splits a ASCII string into n-grams of `ngramsize` symbols and returns the n-gram `simhash`. Is case insensitive.
+
+Can be used for detection of semi-duplicate strings with [bitHammingDistance](../../sql-reference/functions/bit-functions.md#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
+
+**Syntax**
+
+``` sql
+ngramSimHashCaseInsensitive(string[, ngramsize])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramSimHashCaseInsensitive('ClickHouse') AS Hash;
+```
+
+Result:
+
+``` text
+┌──────Hash─┐
+│ 562180645 │
+└───────────┘
+```
+
+## ngramSimHashUTF8 {#ngramsimhashutf8}
+
+Splits a UTF-8 string into n-grams of `ngramsize` symbols and returns the n-gram `simhash`. Is case sensitive.
+
+Can be used for detection of semi-duplicate strings with [bitHammingDistance](../../sql-reference/functions/bit-functions.md#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
+
+**Syntax**
+
+``` sql
+ngramSimHashUTF8(string[, ngramsize])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramSimHashUTF8('ClickHouse') AS Hash;
+```
+
+Result:
+
+``` text
+┌───────Hash─┐
+│ 1628157797 │
+└────────────┘
+```
+
+## ngramSimHashCaseInsensitiveUTF8 {#ngramsimhashcaseinsensitiveutf8}
+
+Splits a UTF-8 string into n-grams of `ngramsize` symbols and returns the n-gram `simhash`. Is case insensitive.
+
+Can be used for detection of semi-duplicate strings with [bitHammingDistance](../../sql-reference/functions/bit-functions.md#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
+
+**Syntax**
+
+``` sql
+ngramSimHashCaseInsensitiveUTF8(string[, ngramsize])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramSimHashCaseInsensitiveUTF8('ClickHouse') AS Hash;
+```
+
+Result:
+
+``` text
+┌───────Hash─┐
+│ 1636742693 │
+└────────────┘
+```
+
+## wordShingleSimHash {#wordshinglesimhash}
+
+Splits a ASCII string into parts (shingles) of `shinglesize` words and returns the word shingle `simhash`. Is case sensitive.
+
+Can be used for detection of semi-duplicate strings with [bitHammingDistance](../../sql-reference/functions/bit-functions.md#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
+
+**Syntax**
+
+``` sql
+wordShingleSimHash(string[, shinglesize])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleSimHash('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Hash;
+```
+
+Result:
+
+``` text
+┌───────Hash─┐
+│ 2328277067 │
+└────────────┘
+```
+
+## wordShingleSimHashCaseInsensitive {#wordshinglesimhashcaseinsensitive}
+
+Splits a ASCII string into parts (shingles) of `shinglesize` words and returns the word shingle `simhash`. Is case insensitive.
+
+Can be used for detection of semi-duplicate strings with [bitHammingDistance](../../sql-reference/functions/bit-functions.md#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
+
+**Syntax**
+
+``` sql
+wordShingleSimHashCaseInsensitive(string[, shinglesize])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleSimHashCaseInsensitive('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Hash;
+```
+
+Result:
+
+``` text
+┌───────Hash─┐
+│ 2194812424 │
+└────────────┘
+```
+
+## wordShingleSimHashUTF8 {#wordshinglesimhashutf8}
+
+Splits a UTF-8 string into parts (shingles) of `shinglesize` words and returns the word shingle `simhash`. Is case sensitive.
+
+Can be used for detection of semi-duplicate strings with [bitHammingDistance](../../sql-reference/functions/bit-functions.md#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
+
+**Syntax**
+
+``` sql
+wordShingleSimHashUTF8(string[, shinglesize])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optinal. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleSimHashUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Hash;
+```
+
+Result:
+
+``` text
+┌───────Hash─┐
+│ 2328277067 │
+└────────────┘
+```
+
+## wordShingleSimHashCaseInsensitiveUTF8 {#wordshinglesimhashcaseinsensitiveutf8}
+
+Splits a UTF-8 string into parts (shingles) of `shinglesize` words and returns the word shingle `simhash`. Is case insensitive.
+
+Can be used for detection of semi-duplicate strings with [bitHammingDistance](../../sql-reference/functions/bit-functions.md#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
+
+**Syntax**
+
+``` sql
+wordShingleSimHashCaseInsensitiveUTF8(string[, shinglesize])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleSimHashCaseInsensitiveUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Hash;
+```
+
+Result:
+
+``` text
+┌───────Hash─┐
+│ 2194812424 │
+└────────────┘
+```
+
+## ngramMinHash {#ngramminhash}
+
+Splits a ASCII string into n-grams of `ngramsize` symbols and calculates hash values for each n-gram. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case sensitive.
+
+Can be used for detection of semi-duplicate strings with [tupleHammingDistance](../../sql-reference/functions/tuple-functions.md#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
+
+**Syntax**
+
+``` sql
+ngramMinHash(string[, ngramsize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two hashes — the minimum and the maximum.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([UInt64](../../sql-reference/data-types/int-uint.md), [UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramMinHash('ClickHouse') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple──────────────────────────────────────┐
+│ (18333312859352735453,9054248444481805918) │
+└────────────────────────────────────────────┘
+```
+
+## ngramMinHashCaseInsensitive {#ngramminhashcaseinsensitive}
+
+Splits a ASCII string into n-grams of `ngramsize` symbols and calculates hash values for each n-gram. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case insensitive.
+
+Can be used for detection of semi-duplicate strings with [tupleHammingDistance](../../sql-reference/functions/tuple-functions.md#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
+
+**Syntax**
+
+``` sql
+ngramMinHashCaseInsensitive(string[, ngramsize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two hashes — the minimum and the maximum.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([UInt64](../../sql-reference/data-types/int-uint.md), [UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramMinHashCaseInsensitive('ClickHouse') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple──────────────────────────────────────┐
+│ (2106263556442004574,13203602793651726206) │
+└────────────────────────────────────────────┘
+```
+
+## ngramMinHashUTF8 {#ngramminhashutf8}
+
+Splits a UTF-8 string into n-grams of `ngramsize` symbols and calculates hash values for each n-gram. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case sensitive.
+
+Can be used for detection of semi-duplicate strings with [tupleHammingDistance](../../sql-reference/functions/tuple-functions.md#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
+
+**Syntax**
+
+``` sql
+ngramMinHashUTF8(string[, ngramsize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two hashes — the minimum and the maximum.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([UInt64](../../sql-reference/data-types/int-uint.md), [UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramMinHashUTF8('ClickHouse') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple──────────────────────────────────────┐
+│ (18333312859352735453,6742163577938632877) │
+└────────────────────────────────────────────┘
+```
+
+## ngramMinHashCaseInsensitiveUTF8 {#ngramminhashcaseinsensitiveutf8}
+
+Splits a UTF-8 string into n-grams of `ngramsize` symbols and calculates hash values for each n-gram. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case insensitive.
+
+Can be used for detection of semi-duplicate strings with [tupleHammingDistance](../../sql-reference/functions/tuple-functions.md#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
+
+**Syntax**
+
+``` sql
+ngramMinHashCaseInsensitiveUTF8(string [, ngramsize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two hashes — the minimum and the maximum.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([UInt64](../../sql-reference/data-types/int-uint.md), [UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramMinHashCaseInsensitiveUTF8('ClickHouse') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple───────────────────────────────────────┐
+│ (12493625717655877135,13203602793651726206) │
+└─────────────────────────────────────────────┘
+```
+
+## ngramMinHashArg {#ngramminhasharg}
+
+Splits a ASCII string into n-grams of `ngramsize` symbols and returns the n-grams with minimum and maximum hashes, calculated by the [ngramMinHash](#ngramminhash) function with the same input. Is case sensitive.
+
+**Syntax**
+
+``` sql
+ngramMinHashArg(string[, ngramsize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two tuples with `hashnum` n-grams each.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md)), [Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md))).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramMinHashArg('ClickHouse') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple─────────────────────────────────────────────────────────────────────────┐
+│ (('ous','ick','lic','Hou','kHo','use'),('Hou','lic','ick','ous','ckH','Cli')) │
+└───────────────────────────────────────────────────────────────────────────────┘
+```
+
+## ngramMinHashArgCaseInsensitive {#ngramminhashargcaseinsensitive}
+
+Splits a ASCII string into n-grams of `ngramsize` symbols and returns the n-grams with minimum and maximum hashes, calculated by the [ngramMinHashCaseInsensitive](#ngramminhashcaseinsensitive) function with the same input. Is case insensitive.
+
+**Syntax**
+
+``` sql
+ngramMinHashArgCaseInsensitive(string[, ngramsize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two tuples with `hashnum` n-grams each.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md)), [Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md))).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramMinHashArgCaseInsensitive('ClickHouse') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple─────────────────────────────────────────────────────────────────────────┐
+│ (('ous','ick','lic','kHo','use','Cli'),('kHo','lic','ick','ous','ckH','Hou')) │
+└───────────────────────────────────────────────────────────────────────────────┘
+```
+
+## ngramMinHashArgUTF8 {#ngramminhashargutf8}
+
+Splits a UTF-8 string into n-grams of `ngramsize` symbols and returns the n-grams with minimum and maximum hashes, calculated by the [ngramMinHashUTF8](#ngramminhashutf8) function with the same input. Is case sensitive.
+
+**Syntax**
+
+``` sql
+ngramMinHashArgUTF8(string[, ngramsize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two tuples with `hashnum` n-grams each.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md)), [Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md))).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramMinHashArgUTF8('ClickHouse') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple─────────────────────────────────────────────────────────────────────────┐
+│ (('ous','ick','lic','Hou','kHo','use'),('kHo','Hou','lic','ick','ous','ckH')) │
+└───────────────────────────────────────────────────────────────────────────────┘
+```
+
+## ngramMinHashArgCaseInsensitiveUTF8 {#ngramminhashargcaseinsensitiveutf8}
+
+Splits a UTF-8 string into n-grams of `ngramsize` symbols and returns the n-grams with minimum and maximum hashes, calculated by the [ngramMinHashCaseInsensitiveUTF8](#ngramminhashcaseinsensitiveutf8) function with the same input. Is case insensitive.
+
+**Syntax**
+
+``` sql
+ngramMinHashArgCaseInsensitiveUTF8(string[, ngramsize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two tuples with `hashnum` n-grams each.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md)), [Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md))).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngramMinHashArgCaseInsensitiveUTF8('ClickHouse') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple─────────────────────────────────────────────────────────────────────────┐
+│ (('ckH','ous','ick','lic','kHo','use'),('kHo','lic','ick','ous','ckH','Hou')) │
+└───────────────────────────────────────────────────────────────────────────────┘
+```
+
+## wordShingleMinHash {#wordshingleminhash}
+
+Splits a ASCII string into parts (shingles) of `shinglesize` words and calculates hash values for each word shingle. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case sensitive.
+
+Can be used for detection of semi-duplicate strings with [tupleHammingDistance](../../sql-reference/functions/tuple-functions.md#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
+
+**Syntax**
+
+``` sql
+wordShingleMinHash(string[, shinglesize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two hashes — the minimum and the maximum.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([UInt64](../../sql-reference/data-types/int-uint.md), [UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleMinHash('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple──────────────────────────────────────┐
+│ (16452112859864147620,5844417301642981317) │
+└────────────────────────────────────────────┘
+```
+
+## wordShingleMinHashCaseInsensitive {#wordshingleminhashcaseinsensitive}
+
+Splits a ASCII string into parts (shingles) of `shinglesize` words and calculates hash values for each word shingle. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case insensitive.
+
+Can be used for detection of semi-duplicate strings with [tupleHammingDistance](../../sql-reference/functions/tuple-functions.md#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
+
+**Syntax**
+
+``` sql
+wordShingleMinHashCaseInsensitive(string[, shinglesize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two hashes — the minimum and the maximum.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([UInt64](../../sql-reference/data-types/int-uint.md), [UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleMinHashCaseInsensitive('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple─────────────────────────────────────┐
+│ (3065874883688416519,1634050779997673240) │
+└───────────────────────────────────────────┘
+```
+
+## wordShingleMinHashUTF8 {#wordshingleminhashutf8}
+
+Splits a UTF-8 string into parts (shingles) of `shinglesize` words and calculates hash values for each word shingle. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case sensitive.
+
+Can be used for detection of semi-duplicate strings with [tupleHammingDistance](../../sql-reference/functions/tuple-functions.md#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
+
+**Syntax**
+
+``` sql
+wordShingleMinHashUTF8(string[, shinglesize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two hashes — the minimum and the maximum.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([UInt64](../../sql-reference/data-types/int-uint.md), [UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleMinHashUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple──────────────────────────────────────┐
+│ (16452112859864147620,5844417301642981317) │
+└────────────────────────────────────────────┘
+```
+
+## wordShingleMinHashCaseInsensitiveUTF8 {#wordshingleminhashcaseinsensitiveutf8}
+
+Splits a UTF-8 string into parts (shingles) of `shinglesize` words and calculates hash values for each word shingle. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case insensitive.
+
+Can be used for detection of semi-duplicate strings with [tupleHammingDistance](../../sql-reference/functions/tuple-functions.md#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
+
+**Syntax**
+
+``` sql
+wordShingleMinHashCaseInsensitiveUTF8(string[, shinglesize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two hashes — the minimum and the maximum.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([UInt64](../../sql-reference/data-types/int-uint.md), [UInt64](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleMinHashCaseInsensitiveUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple─────────────────────────────────────┐
+│ (3065874883688416519,1634050779997673240) │
+└───────────────────────────────────────────┘
+```
+
+## wordShingleMinHashArg {#wordshingleminhasharg}
+
+Splits a ASCII string into parts (shingles) of `shinglesize` words each and returns the shingles with minimum and maximum word hashes, calculated by the [wordshingleMinHash](#wordshingleminhash) function with the same input. Is case sensitive.
+
+**Syntax**
+
+``` sql
+wordShingleMinHashArg(string[, shinglesize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two tuples with `hashnum` word shingles each.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md)), [Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md))).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleMinHashArg('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).', 1, 3) AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple─────────────────────────────────────────────────────────────────┐
+│ (('OLAP','database','analytical'),('online','oriented','processing')) │
+└───────────────────────────────────────────────────────────────────────┘
+```
+
+## wordShingleMinHashArgCaseInsensitive {#wordshingleminhashargcaseinsensitive}
+
+Splits a ASCII string into parts (shingles) of `shinglesize` words each and returns the shingles with minimum and maximum word hashes, calculated by the [wordShingleMinHashCaseInsensitive](#wordshingleminhashcaseinsensitive) function with the same input. Is case insensitive.
+
+**Syntax**
+
+``` sql
+wordShingleMinHashArgCaseInsensitive(string[, shinglesize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two tuples with `hashnum` word shingles each.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md)), [Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md))).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleMinHashArgCaseInsensitive('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).', 1, 3) AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple──────────────────────────────────────────────────────────────────┐
+│ (('queries','database','analytical'),('oriented','processing','DBMS')) │
+└────────────────────────────────────────────────────────────────────────┘
+```
+
+## wordShingleMinHashArgUTF8 {#wordshingleminhashargutf8}
+
+Splits a UTF-8 string into parts (shingles) of `shinglesize` words each and returns the shingles with minimum and maximum word hashes, calculated by the [wordShingleMinHashUTF8](#wordshingleminhashutf8) function with the same input. Is case sensitive.
+
+**Syntax**
+
+``` sql
+wordShingleMinHashArgUTF8(string[, shinglesize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two tuples with `hashnum` word shingles each.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md)), [Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md))).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleMinHashArgUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).', 1, 3) AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple─────────────────────────────────────────────────────────────────┐
+│ (('OLAP','database','analytical'),('online','oriented','processing')) │
+└───────────────────────────────────────────────────────────────────────┘
+```
+
+## wordShingleMinHashArgCaseInsensitiveUTF8 {#wordshingleminhashargcaseinsensitiveutf8}
+
+Splits a UTF-8 string into parts (shingles) of `shinglesize` words each and returns the shingles with minimum and maximum word hashes, calculated by the [wordShingleMinHashCaseInsensitiveUTF8](#wordshingleminhashcaseinsensitiveutf8) function with the same input. Is case insensitive.
+
+**Syntax**
+
+``` sql
+wordShingleMinHashArgCaseInsensitiveUTF8(string[, shinglesize, hashnum])
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md).
+-   `shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+-   Tuple with two tuples with `hashnum` word shingles each.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md)), [Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md))).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT wordShingleMinHashArgCaseInsensitiveUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).', 1, 3) AS Tuple;
+```
+
+Result:
+
+``` text
+┌─Tuple──────────────────────────────────────────────────────────────────┐
+│ (('queries','database','analytical'),('oriented','processing','DBMS')) │
+└────────────────────────────────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/in-functions.md b/docs/en/reference/sql-reference/functions/in-functions.md
new file mode 100644
index 00000000000..ab8ba93daba
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/in-functions.md
@@ -0,0 +1,11 @@
+---
+sidebar_position: 60
+sidebar_label: IN Operator
+---
+
+# Functions for Implementing the IN Operator {#functions-for-implementing-the-in-operator}
+
+## in, notIn, globalIn, globalNotIn {#in-functions}
+
+See the section [IN operators](../../sql-reference/operators/in.md#select-in-operators).
+
diff --git a/docs/en/reference/sql-reference/functions/index.md b/docs/en/reference/sql-reference/functions/index.md
new file mode 100644
index 00000000000..261cf908e07
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/index.md
@@ -0,0 +1,252 @@
+---
+sidebar_position: 32
+sidebar_label: Functions
+---
+
+# Functions 
+
+There are at least\* two types of functions - regular functions (they are just called “functions”) and aggregate functions. These are completely different concepts. Regular functions work as if they are applied to each row separately (for each row, the result of the function does not depend on the other rows). Aggregate functions accumulate a set of values from various rows (i.e. they depend on the entire set of rows).
+
+In this section we discuss regular functions. For aggregate functions, see the section “Aggregate functions”.
+
+\* - There is a third type of function that the ‘arrayJoin’ function belongs to; table functions can also be mentioned separately.\*
+
+## Strong Typing {#strong-typing}
+
+In contrast to standard SQL, ClickHouse has strong typing. In other words, it does not make implicit conversions between types. Each function works for a specific set of types. This means that sometimes you need to use type conversion functions.
+
+## Common Subexpression Elimination {#common-subexpression-elimination}
+
+All expressions in a query that have the same AST (the same record or same result of syntactic parsing) are considered to have identical values. Such expressions are concatenated and executed once. Identical subqueries are also eliminated this way.
+
+## Types of Results {#types-of-results}
+
+All functions return a single return as the result (not several values, and not zero values). The type of result is usually defined only by the types of arguments, not by the values. Exceptions are the tupleElement function (the a.N operator), and the toFixedString function.
+
+## Constants {#constants}
+
+For simplicity, certain functions can only work with constants for some arguments. For example, the right argument of the LIKE operator must be a constant.
+Almost all functions return a constant for constant arguments. The exception is functions that generate random numbers.
+The ‘now’ function returns different values for queries that were run at different times, but the result is considered a constant, since constancy is only important within a single query.
+A constant expression is also considered a constant (for example, the right half of the LIKE operator can be constructed from multiple constants).
+
+Functions can be implemented in different ways for constant and non-constant arguments (different code is executed). But the results for a constant and for a true column containing only the same value should match each other.
+
+## NULL Processing {#null-processing}
+
+Functions have the following behaviors:
+
+-   If at least one of the arguments of the function is `NULL`, the function result is also `NULL`.
+-   Special behavior that is specified individually in the description of each function. In the ClickHouse source code, these functions have `UseDefaultImplementationForNulls=false`.
+
+## Constancy {#constancy}
+
+Functions can’t change the values of their arguments – any changes are returned as the result. Thus, the result of calculating separate functions does not depend on the order in which the functions are written in the query.
+
+## Higher-order functions, `->` operator and lambda(params, expr) function {#higher-order-functions}
+
+Higher-order functions can only accept lambda functions as their functional argument. To pass a lambda function to a higher-order function use `->` operator. The left side of the arrow has a formal parameter, which is any ID, or multiple formal parameters – any IDs in a tuple. The right side of the arrow has an expression that can use these formal parameters, as well as any table columns.
+
+Examples:
+
+```
+x -> 2 * x
+str -> str != Referer
+```
+
+A lambda function that accepts multiple arguments can also be passed to a higher-order function. In this case, the higher-order function is passed several arrays of identical length that these arguments will correspond to.
+
+For some functions the first argument (the lambda function) can be omitted. In this case, identical mapping is assumed.
+
+## SQL User Defined Functions {#user-defined-functions}
+
+Custom functions from lambda expressions can be created using the [CREATE FUNCTION](../statements/create/function.md) statement. To delete these functions use the [DROP FUNCTION](../statements/drop.md#drop-function) statement.
+
+## Executable User Defined Functions {#executable-user-defined-functions}
+ClickHouse can call any external executable program or script to process data. Describe such functions in a [configuration file](../../operations/configuration-files.md) and add the path of that file to the main configuration in `user_defined_executable_functions_config` setting. If a wildcard symbol `*` is used in the path, then all files matching the pattern are loaded. Example:
+``` xml
+<user_defined_executable_functions_config>*_function.xml</user_defined_executable_functions_config>
+```
+User defined function configurations are searched relative to the path specified in the `user_files_path` setting.
+
+A function configuration contains the following settings:
+
+-   `name` - a function name.
+-   `command` - script name to execute or command if `execute_direct` is false.
+-   `argument` - argument description with the `type`, and optional `name` of an argument. Each argument is described in a separate setting. Specifying name is necessary if argument names are part of serialization for user defined function format like [Native](../../interfaces/formats.md#native) or [JSONEachRow](../../interfaces/formats.md#jsoneachrow). Default argument name value is `c` + argument_number.
+-   `format` - a [format](../../interfaces/formats.md) in which arguments are passed to the command.
+-   `return_type` - the type of a returned value.
+-   `return_name` - name of retuned value. Specifying return name is necessary if return name is part of serialization for user defined function format like [Native](../../interfaces/formats.md#native) or [JSONEachRow](../../interfaces/formats.md#jsoneachrow). Optional. Default value is `result`.
+-   `type` - an executable type. If `type` is set to `executable` then single command is started. If it is set to `executable_pool` then a pool of commands is created.
+-   `max_command_execution_time` - maximum execution time in seconds for processing block of data. This setting is valid for `executable_pool` commands only. Optional. Default value is `10`.
+-   `command_termination_timeout` - time in seconds during which a command should finish after its pipe is closed. After that time `SIGTERM` is sent to the process executing the command. Optional. Default value is `10`.
+-   `command_read_timeout` - timeout for reading data from command stdout in milliseconds. Default value 10000. Optional parameter.
+-   `command_write_timeout` - timeout for writing data to command stdin in milliseconds. Default value 10000. Optional parameter.
+-   `pool_size` - the size of a command pool. Optional. Default value is `16`.
+-   `send_chunk_header` - controls whether to send row count before sending a chunk of data to process. Optional. Default value is `false`.
+-   `execute_direct` - If `execute_direct` = `1`, then `command` will be searched inside user_scripts folder. Additional script arguments can be specified using whitespace separator. Example: `script_name arg1 arg2`. If `execute_direct` = `0`, `command` is passed as argument for `bin/sh -c`. Default value is `1`. Optional parameter.
+-   `lifetime` - the reload interval of a function in seconds. If it is set to `0` then the function is not reloaded. Default value is `0`. Optional parameter.
+
+The command must read arguments from `STDIN` and must output the result to `STDOUT`. The command must process arguments iteratively. That is after processing a chunk of arguments it must wait for the next chunk.
+
+**Example**
+Creating `test_function` using XML configuration.
+File test_function.xml.
+```xml
+<functions>
+    <function>
+        <type>executable</type>
+        <name>test_function_python</name>
+        <return_type>String</return_type>
+        <argument>
+            <type>UInt64</type>
+            <name>value</name>
+        </argument>
+        <format>TabSeparated</format>
+        <command>test_function.py</command>
+    </function>
+</functions>
+```
+
+Script file inside `user_scripts` folder `test_function.py`.
+
+```python
+#!/usr/bin/python3
+
+import sys
+
+if __name__ == '__main__':
+    for line in sys.stdin:
+        print("Value " + line, end='')
+        sys.stdout.flush()
+```
+
+Query:
+
+``` sql
+SELECT test_function_python(toUInt64(2));
+```
+
+Result:
+
+``` text
+┌─test_function_python(2)─┐
+│ Value 2                 │
+└─────────────────────────┘
+```
+
+Creating `test_function_sum` manually specifying `execute_direct` to `0` using XML configuration.
+File test_function.xml.
+```xml
+<functions>
+    <function>
+        <type>executable</type>
+        <name>test_function_sum</name>
+        <return_type>UInt64</return_type>
+        <argument>
+            <type>UInt64</type>
+            <name>lhs</name>
+        </argument>
+        <argument>
+            <type>UInt64</type>
+            <name>rhs</name>
+        </argument>
+        <format>TabSeparated</format>
+        <command>cd /; clickhouse-local --input-format TabSeparated --output-format TabSeparated --structure 'x UInt64, y UInt64' --query "SELECT x + y FROM table"</command>
+        <execute_direct>0</execute_direct>
+    </function>
+</functions>
+```
+
+Query:
+
+``` sql
+SELECT test_function_sum(2, 2);
+```
+
+Result:
+
+``` text
+┌─test_function_sum(2, 2)─┐
+│                       4 │
+└─────────────────────────┘
+```
+
+Creating `test_function_sum_json` with named arguments and format [JSONEachRow](../../interfaces/formats.md#jsoneachrow) using XML configuration.
+File test_function.xml.
+```xml
+<function>
+    <type>executable</type>
+    <name>test_function_sum_json</name>
+    <return_type>UInt64</return_type>
+    <return_name>result_name</return_name>
+    <argument>
+        <type>UInt64</type>
+        <name>argument_1</name>
+    </argument>
+    <argument>
+        <type>UInt64</type>
+        <name>argument_2</name>
+    </argument>
+    <format>JSONEachRow</format>
+    <command>test_function_sum_json.py</command>
+</function>
+```
+
+Script file inside `user_scripts` folder `test_function_sum_json.py`.
+
+```python
+#!/usr/bin/python3
+
+import sys
+import json
+
+if __name__ == '__main__':
+    for line in sys.stdin:
+        value = json.loads(line)
+        first_arg = int(value['argument_1'])
+        second_arg = int(value['argument_2'])
+        result = {'result_name': first_arg + second_arg}
+        print(json.dumps(result), end='\n')
+        sys.stdout.flush()
+```
+
+Query:
+
+``` sql
+SELECT test_function_sum_json(2, 2);
+```
+
+Result:
+
+``` text
+┌─test_function_sum_json(2, 2)─┐
+│                            4 │
+└──────────────────────────────┘
+```
+
+## Error Handling {#error-handling}
+
+Some functions might throw an exception if the data is invalid. In this case, the query is canceled and an error text is returned to the client. For distributed processing, when an exception occurs on one of the servers, the other servers also attempt to abort the query.
+
+## Evaluation of Argument Expressions {#evaluation-of-argument-expressions}
+
+In almost all programming languages, one of the arguments might not be evaluated for certain operators. This is usually the operators `&&`, `||`, and `?:`.
+But in ClickHouse, arguments of functions (operators) are always evaluated. This is because entire parts of columns are evaluated at once, instead of calculating each row separately.
+
+## Performing Functions for Distributed Query Processing {#performing-functions-for-distributed-query-processing}
+
+For distributed query processing, as many stages of query processing as possible are performed on remote servers, and the rest of the stages (merging intermediate results and everything after that) are performed on the requestor server.
+
+This means that functions can be performed on different servers.
+For example, in the query `SELECT f(sum(g(x))) FROM distributed_table GROUP BY h(y),`
+
+-   if a `distributed_table` has at least two shards, the functions ‘g’ and ‘h’ are performed on remote servers, and the function ‘f’ is performed on the requestor server.
+-   if a `distributed_table` has only one shard, all the ‘f’, ‘g’, and ‘h’ functions are performed on this shard’s server.
+
+The result of a function usually does not depend on which server it is performed on. However, sometimes this is important.
+For example, functions that work with dictionaries use the dictionary that exists on the server they are running on.
+Another example is the `hostName` function, which returns the name of the server it is running on in order to make `GROUP BY` by servers in a `SELECT` query.
+
+If a function in a query is performed on the requestor server, but you need to perform it on remote servers, you can wrap it in an ‘any’ aggregate function or add it to a key in `GROUP BY`.
+
diff --git a/docs/en/reference/sql-reference/functions/introspection.md b/docs/en/reference/sql-reference/functions/introspection.md
new file mode 100644
index 00000000000..694d07f18dc
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/introspection.md
@@ -0,0 +1,478 @@
+---
+sidebar_position: 65
+sidebar_label: Introspection
+---
+
+# Introspection Functions {#introspection-functions}
+
+You can use functions described in this chapter to introspect [ELF](https://en.wikipedia.org/wiki/Executable_and_Linkable_Format) and [DWARF](https://en.wikipedia.org/wiki/DWARF) for query profiling.
+
+:::warning    
+These functions are slow and may impose security considerations.
+:::
+
+For proper operation of introspection functions:
+
+-   Install the `clickhouse-common-static-dbg` package.
+
+-   Set the [allow_introspection_functions](../../operations/settings/settings.md#settings-allow_introspection_functions) setting to 1.
+
+        For security reasons introspection functions are disabled by default.
+
+ClickHouse saves profiler reports to the [trace_log](../../operations/system-tables/trace_log.md#system_tables-trace_log) system table. Make sure the table and profiler are configured properly.
+
+## addressToLine {#addresstoline}
+
+Converts virtual memory address inside ClickHouse server process to the filename and the line number in ClickHouse source code.
+
+If you use official ClickHouse packages, you need to install the `clickhouse-common-static-dbg` package.
+
+**Syntax**
+
+``` sql
+addressToLine(address_of_binary_instruction)
+```
+
+**Arguments**
+
+-   `address_of_binary_instruction` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Address of instruction in a running process.
+
+**Returned value**
+
+-   Source code filename and the line number in this file delimited by colon.
+
+        For example, `/build/obj-x86_64-linux-gnu/../src/Common/ThreadPool.cpp:199`, where `199` is a line number.
+
+-   Name of a binary, if the function couldn’t find the debug information.
+
+-   Empty string, if the address is not valid.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Enabling introspection functions:
+
+``` sql
+SET allow_introspection_functions=1;
+```
+
+Selecting the first string from the `trace_log` system table:
+
+``` sql
+SELECT * FROM system.trace_log LIMIT 1 \G;
+```
+
+``` text
+Row 1:
+──────
+event_date:              2019-11-19
+event_time:              2019-11-19 18:57:23
+revision:                54429
+timer_type:              Real
+thread_number:           48
+query_id:                421b6855-1858-45a5-8f37-f383409d6d72
+trace:                   [140658411141617,94784174532828,94784076370703,94784076372094,94784076361020,94784175007680,140658411116251,140658403895439]
+```
+
+The `trace` field contains the stack trace at the moment of sampling.
+
+Getting the source code filename and the line number for a single address:
+
+``` sql
+SELECT addressToLine(94784076370703) \G;
+```
+
+``` text
+Row 1:
+──────
+addressToLine(94784076370703): /build/obj-x86_64-linux-gnu/../src/Common/ThreadPool.cpp:199
+```
+
+Applying the function to the whole stack trace:
+
+``` sql
+SELECT
+    arrayStringConcat(arrayMap(x -> addressToLine(x), trace), '\n') AS trace_source_code_lines
+FROM system.trace_log
+LIMIT 1
+\G
+```
+
+The [arrayMap](../../sql-reference/functions/array-functions.md#array-map) function allows to process each individual element of the `trace` array by the `addressToLine` function. The result of this processing you see in the `trace_source_code_lines` column of output.
+
+``` text
+Row 1:
+──────
+trace_source_code_lines: /lib/x86_64-linux-gnu/libpthread-2.27.so
+/usr/lib/debug/usr/bin/clickhouse
+/build/obj-x86_64-linux-gnu/../src/Common/ThreadPool.cpp:199
+/build/obj-x86_64-linux-gnu/../src/Common/ThreadPool.h:155
+/usr/include/c++/9/bits/atomic_base.h:551
+/usr/lib/debug/usr/bin/clickhouse
+/lib/x86_64-linux-gnu/libpthread-2.27.so
+/build/glibc-OTsEL5/glibc-2.27/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:97
+```
+
+## addressToLineWithInlines {#addresstolinewithinlines}
+
+Similar to `addressToLine`, but it will return an Array with all inline functions, and will be much slower as a price.
+
+If you use official ClickHouse packages, you need to install the `clickhouse-common-static-dbg` package.
+
+**Syntax**
+
+``` sql
+addressToLineWithInlines(address_of_binary_instruction)
+```
+
+**Arguments**
+
+-   `address_of_binary_instruction` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Address of instruction in a running process.
+
+**Returned value**
+
+-   Array which first element is source code filename and the line number in this file delimited by colon. And from second element, inline functions' source code filename and line number and function name are listed.
+
+-   Array with single element which is name of a binary, if the function couldn’t find the debug information.
+
+-   Empty array, if the address is not valid.
+
+Type: [Array(String)](../../sql-reference/data-types/array.md).
+
+**Example**
+
+Enabling introspection functions:
+
+``` sql
+SET allow_introspection_functions=1;
+```
+
+Applying the function to address.
+
+```sql
+SELECT addressToLineWithInlines(531055181::UInt64);
+```
+
+``` text
+┌─addressToLineWithInlines(CAST('531055181', 'UInt64'))────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ ['./src/Functions/addressToLineWithInlines.cpp:98','./build_normal_debug/./src/Functions/addressToLineWithInlines.cpp:176:DB::(anonymous namespace)::FunctionAddressToLineWithInlines::implCached(unsigned long) const'] │
+└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+Applying the function to the whole stack trace:
+
+``` sql
+SELECT
+    ta, addressToLineWithInlines(arrayJoin(trace) as ta)
+FROM system.trace_log
+WHERE
+    query_id = '5e173544-2020-45de-b645-5deebe2aae54';
+```
+
+The [arrayJoin](../../sql-reference/functions/array-functions.md#array-functions-join) functions will split array to rows.
+
+``` text
+┌────────ta─┬─addressToLineWithInlines(arrayJoin(trace))───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ 365497529 │ ['./build_normal_debug/./contrib/libcxx/include/string_view:252']                                                                                                                                                        │
+│ 365593602 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:191']                                                                                                                                                                      │
+│ 365593866 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:0']                                                                                                                                                                        │
+│ 365592528 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:0']                                                                                                                                                                        │
+│ 365591003 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:477']                                                                                                                                                                      │
+│ 365590479 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:442']                                                                                                                                                                      │
+│ 365590600 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:457']                                                                                                                                                                      │
+│ 365598941 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:0']                                                                                                                                                                        │
+│ 365607098 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:0']                                                                                                                                                                        │
+│ 365590571 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:451']                                                                                                                                                                      │
+│ 365598941 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:0']                                                                                                                                                                        │
+│ 365607098 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:0']                                                                                                                                                                        │
+│ 365590571 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:451']                                                                                                                                                                      │
+│ 365598941 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:0']                                                                                                                                                                        │
+│ 365607098 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:0']                                                                                                                                                                        │
+│ 365590571 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:451']                                                                                                                                                                      │
+│ 365598941 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:0']                                                                                                                                                                        │
+│ 365597289 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:807']                                                                                                                                                                      │
+│ 365599840 │ ['./build_normal_debug/./src/Common/Dwarf.cpp:1118']                                                                                                                                                                     │
+│ 531058145 │ ['./build_normal_debug/./src/Functions/addressToLineWithInlines.cpp:152']                                                                                                                                                │
+│ 531055181 │ ['./src/Functions/addressToLineWithInlines.cpp:98','./build_normal_debug/./src/Functions/addressToLineWithInlines.cpp:176:DB::(anonymous namespace)::FunctionAddressToLineWithInlines::implCached(unsigned long) const'] │
+│ 422333613 │ ['./build_normal_debug/./src/Functions/IFunctionAdaptors.h:21']                                                                                                                                                          │
+│ 586866022 │ ['./build_normal_debug/./src/Functions/IFunction.cpp:216']                                                                                                                                                               │
+│ 586869053 │ ['./build_normal_debug/./src/Functions/IFunction.cpp:264']                                                                                                                                                               │
+│ 586873237 │ ['./build_normal_debug/./src/Functions/IFunction.cpp:334']                                                                                                                                                               │
+│ 597901620 │ ['./build_normal_debug/./src/Interpreters/ExpressionActions.cpp:601']                                                                                                                                                    │
+│ 597898534 │ ['./build_normal_debug/./src/Interpreters/ExpressionActions.cpp:718']                                                                                                                                                    │
+│ 630442912 │ ['./build_normal_debug/./src/Processors/Transforms/ExpressionTransform.cpp:23']                                                                                                                                          │
+│ 546354050 │ ['./build_normal_debug/./src/Processors/ISimpleTransform.h:38']                                                                                                                                                          │
+│ 626026993 │ ['./build_normal_debug/./src/Processors/ISimpleTransform.cpp:89']                                                                                                                                                        │
+│ 626294022 │ ['./build_normal_debug/./src/Processors/Executors/ExecutionThreadContext.cpp:45']                                                                                                                                        │
+│ 626293730 │ ['./build_normal_debug/./src/Processors/Executors/ExecutionThreadContext.cpp:63']                                                                                                                                        │
+│ 626169525 │ ['./build_normal_debug/./src/Processors/Executors/PipelineExecutor.cpp:213']                                                                                                                                             │
+│ 626170308 │ ['./build_normal_debug/./src/Processors/Executors/PipelineExecutor.cpp:178']                                                                                                                                             │
+│ 626166348 │ ['./build_normal_debug/./src/Processors/Executors/PipelineExecutor.cpp:329']                                                                                                                                             │
+│ 626163461 │ ['./build_normal_debug/./src/Processors/Executors/PipelineExecutor.cpp:84']                                                                                                                                              │
+│ 626323536 │ ['./build_normal_debug/./src/Processors/Executors/PullingAsyncPipelineExecutor.cpp:85']                                                                                                                                  │
+│ 626323277 │ ['./build_normal_debug/./src/Processors/Executors/PullingAsyncPipelineExecutor.cpp:112']                                                                                                                                 │
+│ 626323133 │ ['./build_normal_debug/./contrib/libcxx/include/type_traits:3682']                                                                                                                                                       │
+│ 626323041 │ ['./build_normal_debug/./contrib/libcxx/include/tuple:1415']                                                                                                                                                             │
+└───────────┴──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+
+```
+
+
+## addressToSymbol {#addresstosymbol}
+
+Converts virtual memory address inside ClickHouse server process to the symbol from ClickHouse object files.
+
+**Syntax**
+
+``` sql
+addressToSymbol(address_of_binary_instruction)
+```
+
+**Arguments**
+
+-   `address_of_binary_instruction` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Address of instruction in a running process.
+
+**Returned value**
+
+-   Symbol from ClickHouse object files.
+-   Empty string, if the address is not valid.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Enabling introspection functions:
+
+``` sql
+SET allow_introspection_functions=1;
+```
+
+Selecting the first string from the `trace_log` system table:
+
+``` sql
+SELECT * FROM system.trace_log LIMIT 1 \G;
+```
+
+``` text
+Row 1:
+──────
+event_date:    2019-11-20
+event_time:    2019-11-20 16:57:59
+revision:      54429
+timer_type:    Real
+thread_number: 48
+query_id:      724028bf-f550-45aa-910d-2af6212b94ac
+trace:         [94138803686098,94138815010911,94138815096522,94138815101224,94138815102091,94138814222988,94138806823642,94138814457211,94138806823642,94138814457211,94138806823642,94138806795179,94138806796144,94138753770094,94138753771646,94138753760572,94138852407232,140399185266395,140399178045583]
+```
+
+The `trace` field contains the stack trace at the moment of sampling.
+
+Getting a symbol for a single address:
+
+``` sql
+SELECT addressToSymbol(94138803686098) \G;
+```
+
+``` text
+Row 1:
+──────
+addressToSymbol(94138803686098): _ZNK2DB24IAggregateFunctionHelperINS_20AggregateFunctionSumImmNS_24AggregateFunctionSumDataImEEEEE19addBatchSinglePlaceEmPcPPKNS_7IColumnEPNS_5ArenaE
+```
+
+Applying the function to the whole stack trace:
+
+``` sql
+SELECT
+    arrayStringConcat(arrayMap(x -> addressToSymbol(x), trace), '\n') AS trace_symbols
+FROM system.trace_log
+LIMIT 1
+\G
+```
+
+The [arrayMap](../../sql-reference/functions/array-functions.md#array-map) function allows to process each individual element of the `trace` array by the `addressToSymbols` function. The result of this processing you see in the `trace_symbols` column of output.
+
+``` text
+Row 1:
+──────
+trace_symbols: _ZNK2DB24IAggregateFunctionHelperINS_20AggregateFunctionSumImmNS_24AggregateFunctionSumDataImEEEEE19addBatchSinglePlaceEmPcPPKNS_7IColumnEPNS_5ArenaE
+_ZNK2DB10Aggregator21executeWithoutKeyImplERPcmPNS0_28AggregateFunctionInstructionEPNS_5ArenaE
+_ZN2DB10Aggregator14executeOnBlockESt6vectorIN3COWINS_7IColumnEE13immutable_ptrIS3_EESaIS6_EEmRNS_22AggregatedDataVariantsERS1_IPKS3_SaISC_EERS1_ISE_SaISE_EERb
+_ZN2DB10Aggregator14executeOnBlockERKNS_5BlockERNS_22AggregatedDataVariantsERSt6vectorIPKNS_7IColumnESaIS9_EERS6_ISB_SaISB_EERb
+_ZN2DB10Aggregator7executeERKSt10shared_ptrINS_17IBlockInputStreamEERNS_22AggregatedDataVariantsE
+_ZN2DB27AggregatingBlockInputStream8readImplEv
+_ZN2DB17IBlockInputStream4readEv
+_ZN2DB26ExpressionBlockInputStream8readImplEv
+_ZN2DB17IBlockInputStream4readEv
+_ZN2DB26ExpressionBlockInputStream8readImplEv
+_ZN2DB17IBlockInputStream4readEv
+_ZN2DB28AsynchronousBlockInputStream9calculateEv
+_ZNSt17_Function_handlerIFvvEZN2DB28AsynchronousBlockInputStream4nextEvEUlvE_E9_M_invokeERKSt9_Any_data
+_ZN14ThreadPoolImplI20ThreadFromGlobalPoolE6workerESt14_List_iteratorIS0_E
+_ZZN20ThreadFromGlobalPoolC4IZN14ThreadPoolImplIS_E12scheduleImplIvEET_St8functionIFvvEEiSt8optionalImEEUlvE1_JEEEOS4_DpOT0_ENKUlvE_clEv
+_ZN14ThreadPoolImplISt6threadE6workerESt14_List_iteratorIS0_E
+execute_native_thread_routine
+start_thread
+clone
+```
+
+## demangle {#demangle}
+
+Converts a symbol that you can get using the [addressToSymbol](#addresstosymbol) function to the C++ function name.
+
+**Syntax**
+
+``` sql
+demangle(symbol)
+```
+
+**Arguments**
+
+-   `symbol` ([String](../../sql-reference/data-types/string.md)) — Symbol from an object file.
+
+**Returned value**
+
+-   Name of the C++ function.
+-   Empty string if a symbol is not valid.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Enabling introspection functions:
+
+``` sql
+SET allow_introspection_functions=1;
+```
+
+Selecting the first string from the `trace_log` system table:
+
+``` sql
+SELECT * FROM system.trace_log LIMIT 1 \G;
+```
+
+``` text
+Row 1:
+──────
+event_date:    2019-11-20
+event_time:    2019-11-20 16:57:59
+revision:      54429
+timer_type:    Real
+thread_number: 48
+query_id:      724028bf-f550-45aa-910d-2af6212b94ac
+trace:         [94138803686098,94138815010911,94138815096522,94138815101224,94138815102091,94138814222988,94138806823642,94138814457211,94138806823642,94138814457211,94138806823642,94138806795179,94138806796144,94138753770094,94138753771646,94138753760572,94138852407232,140399185266395,140399178045583]
+```
+
+The `trace` field contains the stack trace at the moment of sampling.
+
+Getting a function name for a single address:
+
+``` sql
+SELECT demangle(addressToSymbol(94138803686098)) \G;
+```
+
+``` text
+Row 1:
+──────
+demangle(addressToSymbol(94138803686098)): DB::IAggregateFunctionHelper<DB::AggregateFunctionSum<unsigned long, unsigned long, DB::AggregateFunctionSumData<unsigned long> > >::addBatchSinglePlace(unsigned long, char*, DB::IColumn const**, DB::Arena*) const
+```
+
+Applying the function to the whole stack trace:
+
+``` sql
+SELECT
+    arrayStringConcat(arrayMap(x -> demangle(addressToSymbol(x)), trace), '\n') AS trace_functions
+FROM system.trace_log
+LIMIT 1
+\G
+```
+
+The [arrayMap](../../sql-reference/functions/array-functions.md#array-map) function allows to process each individual element of the `trace` array by the `demangle` function. The result of this processing you see in the `trace_functions` column of output.
+
+``` text
+Row 1:
+──────
+trace_functions: DB::IAggregateFunctionHelper<DB::AggregateFunctionSum<unsigned long, unsigned long, DB::AggregateFunctionSumData<unsigned long> > >::addBatchSinglePlace(unsigned long, char*, DB::IColumn const**, DB::Arena*) const
+DB::Aggregator::executeWithoutKeyImpl(char*&, unsigned long, DB::Aggregator::AggregateFunctionInstruction*, DB::Arena*) const
+DB::Aggregator::executeOnBlock(std::vector<COW<DB::IColumn>::immutable_ptr<DB::IColumn>, std::allocator<COW<DB::IColumn>::immutable_ptr<DB::IColumn> > >, unsigned long, DB::AggregatedDataVariants&, std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> >&, std::vector<std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> >, std::allocator<std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> > > >&, bool&)
+DB::Aggregator::executeOnBlock(DB::Block const&, DB::AggregatedDataVariants&, std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> >&, std::vector<std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> >, std::allocator<std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> > > >&, bool&)
+DB::Aggregator::execute(std::shared_ptr<DB::IBlockInputStream> const&, DB::AggregatedDataVariants&)
+DB::AggregatingBlockInputStream::readImpl()
+DB::IBlockInputStream::read()
+DB::ExpressionBlockInputStream::readImpl()
+DB::IBlockInputStream::read()
+DB::ExpressionBlockInputStream::readImpl()
+DB::IBlockInputStream::read()
+DB::AsynchronousBlockInputStream::calculate()
+std::_Function_handler<void (), DB::AsynchronousBlockInputStream::next()::{lambda()#1}>::_M_invoke(std::_Any_data const&)
+ThreadPoolImpl<ThreadFromGlobalPool>::worker(std::_List_iterator<ThreadFromGlobalPool>)
+ThreadFromGlobalPool::ThreadFromGlobalPool<ThreadPoolImpl<ThreadFromGlobalPool>::scheduleImpl<void>(std::function<void ()>, int, std::optional<unsigned long>)::{lambda()#3}>(ThreadPoolImpl<ThreadFromGlobalPool>::scheduleImpl<void>(std::function<void ()>, int, std::optional<unsigned long>)::{lambda()#3}&&)::{lambda()#1}::operator()() const
+ThreadPoolImpl<std::thread>::worker(std::_List_iterator<std::thread>)
+execute_native_thread_routine
+start_thread
+clone
+```
+## tid {#tid}
+
+Returns id of the thread, in which current [Block](https://clickhouse.com/docs/en/development/architecture/#block) is processed.
+
+**Syntax**
+
+``` sql
+tid()
+```
+
+**Returned value**
+
+-   Current thread id. [Uint64](../../sql-reference/data-types/int-uint.md#uint-ranges).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT tid();
+```
+
+Result:
+
+``` text
+┌─tid()─┐
+│  3878 │
+└───────┘
+```
+
+## logTrace {#logtrace}
+
+Emits trace log message to server log for each [Block](https://clickhouse.com/docs/en/development/architecture/#block).
+
+**Syntax**
+
+``` sql
+logTrace('message')
+```
+
+**Arguments**
+
+-   `message` — Message that is emitted to server log. [String](../../sql-reference/data-types/string.md#string).
+
+**Returned value**
+
+-   Always returns 0.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT logTrace('logTrace message');
+```
+
+Result:
+
+``` text
+┌─logTrace('logTrace message')─┐
+│                            0 │
+└──────────────────────────────┘
+```
+
diff --git a/docs/en/reference/sql-reference/functions/ip-address-functions.md b/docs/en/reference/sql-reference/functions/ip-address-functions.md
new file mode 100644
index 00000000000..c293c1ff317
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/ip-address-functions.md
@@ -0,0 +1,448 @@
+---
+sidebar_position: 55
+sidebar_label: IP Addresses
+---
+
+# Functions for Working with IPv4 and IPv6 Addresses {#functions-for-working-with-ip-addresses}
+
+## IPv4NumToString(num) {#ipv4numtostringnum}
+
+Takes a UInt32 number. Interprets it as an IPv4 address in big endian. Returns a string containing the corresponding IPv4 address in the format A.B.C.d (dot-separated numbers in decimal form).
+
+Alias: `INET_NTOA`.
+
+## IPv4StringToNum(s) {#ipv4stringtonums}
+
+The reverse function of IPv4NumToString. If the IPv4 address has an invalid format, it returns 0.
+
+Alias: `INET_ATON`.
+
+## IPv4NumToStringClassC(num) {#ipv4numtostringclasscnum}
+
+Similar to IPv4NumToString, but using xxx instead of the last octet.
+
+Example:
+
+``` sql
+SELECT
+    IPv4NumToStringClassC(ClientIP) AS k,
+    count() AS c
+FROM test.hits
+GROUP BY k
+ORDER BY c DESC
+LIMIT 10
+```
+
+``` text
+┌─k──────────────┬─────c─┐
+│ 83.149.9.xxx   │ 26238 │
+│ 217.118.81.xxx │ 26074 │
+│ 213.87.129.xxx │ 25481 │
+│ 83.149.8.xxx   │ 24984 │
+│ 217.118.83.xxx │ 22797 │
+│ 78.25.120.xxx  │ 22354 │
+│ 213.87.131.xxx │ 21285 │
+│ 78.25.121.xxx  │ 20887 │
+│ 188.162.65.xxx │ 19694 │
+│ 83.149.48.xxx  │ 17406 │
+└────────────────┴───────┘
+```
+
+Since using ‘xxx’ is highly unusual, this may be changed in the future. We recommend that you do not rely on the exact format of this fragment.
+
+### IPv6NumToString(x) {#ipv6numtostringx}
+
+Accepts a FixedString(16) value containing the IPv6 address in binary format. Returns a string containing this address in text format.
+IPv6-mapped IPv4 addresses are output in the format ::ffff:111.222.33.44.
+
+Alias: `INET6_NTOA`.
+
+Examples:
+
+``` sql
+SELECT IPv6NumToString(toFixedString(unhex('2A0206B8000000000000000000000011'), 16)) AS addr;
+```
+
+``` text
+┌─addr─────────┐
+│ 2a02:6b8::11 │
+└──────────────┘
+```
+
+``` sql
+SELECT
+    IPv6NumToString(ClientIP6 AS k),
+    count() AS c
+FROM hits_all
+WHERE EventDate = today() AND substring(ClientIP6, 1, 12) != unhex('00000000000000000000FFFF')
+GROUP BY k
+ORDER BY c DESC
+LIMIT 10
+```
+
+``` text
+┌─IPv6NumToString(ClientIP6)──────────────┬─────c─┐
+│ 2a02:2168:aaa:bbbb::2                   │ 24695 │
+│ 2a02:2698:abcd:abcd:abcd:abcd:8888:5555 │ 22408 │
+│ 2a02:6b8:0:fff::ff                      │ 16389 │
+│ 2a01:4f8:111:6666::2                    │ 16016 │
+│ 2a02:2168:888:222::1                    │ 15896 │
+│ 2a01:7e00::ffff:ffff:ffff:222           │ 14774 │
+│ 2a02:8109:eee:ee:eeee:eeee:eeee:eeee    │ 14443 │
+│ 2a02:810b:8888:888:8888:8888:8888:8888  │ 14345 │
+│ 2a02:6b8:0:444:4444:4444:4444:4444      │ 14279 │
+│ 2a01:7e00::ffff:ffff:ffff:ffff          │ 13880 │
+└─────────────────────────────────────────┴───────┘
+```
+
+``` sql
+SELECT
+    IPv6NumToString(ClientIP6 AS k),
+    count() AS c
+FROM hits_all
+WHERE EventDate = today()
+GROUP BY k
+ORDER BY c DESC
+LIMIT 10
+```
+
+``` text
+┌─IPv6NumToString(ClientIP6)─┬──────c─┐
+│ ::ffff:94.26.111.111       │ 747440 │
+│ ::ffff:37.143.222.4        │ 529483 │
+│ ::ffff:5.166.111.99        │ 317707 │
+│ ::ffff:46.38.11.77         │ 263086 │
+│ ::ffff:79.105.111.111      │ 186611 │
+│ ::ffff:93.92.111.88        │ 176773 │
+│ ::ffff:84.53.111.33        │ 158709 │
+│ ::ffff:217.118.11.22       │ 154004 │
+│ ::ffff:217.118.11.33       │ 148449 │
+│ ::ffff:217.118.11.44       │ 148243 │
+└────────────────────────────┴────────┘
+```
+
+## IPv6StringToNum {#ipv6stringtonums}
+
+The reverse function of [IPv6NumToString](#ipv6numtostringx). If the IPv6 address has an invalid format, it returns a string of null bytes.
+
+If the input string contains a valid IPv4 address, returns its IPv6 equivalent.
+HEX can be uppercase or lowercase.
+
+Alias: `INET6_ATON`.
+
+**Syntax**
+
+``` sql
+IPv6StringToNum(string)
+```
+
+**Argument**
+
+-   `string` — IP address. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   IPv6 address in binary format.
+
+Type: [FixedString(16)](../../sql-reference/data-types/fixedstring.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT addr, cutIPv6(IPv6StringToNum(addr), 0, 0) FROM (SELECT ['notaddress', '127.0.0.1', '1111::ffff'] AS addr) ARRAY JOIN addr;
+```
+
+Result:
+
+``` text
+┌─addr───────┬─cutIPv6(IPv6StringToNum(addr), 0, 0)─┐
+│ notaddress │ ::                                   │
+│ 127.0.0.1  │ ::ffff:127.0.0.1                     │
+│ 1111::ffff │ 1111::ffff                           │
+└────────────┴──────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [cutIPv6](#cutipv6x-bytestocutforipv6-bytestocutforipv4).
+
+## IPv4ToIPv6(x) {#ipv4toipv6x}
+
+Takes a `UInt32` number. Interprets it as an IPv4 address in [big endian](https://en.wikipedia.org/wiki/Endianness). Returns a `FixedString(16)` value containing the IPv6 address in binary format. Examples:
+
+``` sql
+SELECT IPv6NumToString(IPv4ToIPv6(IPv4StringToNum('192.168.0.1'))) AS addr;
+```
+
+``` text
+┌─addr───────────────┐
+│ ::ffff:192.168.0.1 │
+└────────────────────┘
+```
+
+## cutIPv6(x, bytesToCutForIPv6, bytesToCutForIPv4) {#cutipv6x-bytestocutforipv6-bytestocutforipv4}
+
+Accepts a FixedString(16) value containing the IPv6 address in binary format. Returns a string containing the address of the specified number of bytes removed in text format. For example:
+
+``` sql
+WITH
+    IPv6StringToNum('2001:0DB8:AC10:FE01:FEED:BABE:CAFE:F00D') AS ipv6,
+    IPv4ToIPv6(IPv4StringToNum('192.168.0.1')) AS ipv4
+SELECT
+    cutIPv6(ipv6, 2, 0),
+    cutIPv6(ipv4, 0, 2)
+```
+
+``` text
+┌─cutIPv6(ipv6, 2, 0)─────────────────┬─cutIPv6(ipv4, 0, 2)─┐
+│ 2001:db8:ac10:fe01:feed:babe:cafe:0 │ ::ffff:192.168.0.0  │
+└─────────────────────────────────────┴─────────────────────┘
+```
+
+## IPv4CIDRToRange(ipv4, Cidr), {#ipv4cidrtorangeipv4-cidr}
+
+Accepts an IPv4 and an UInt8 value containing the [CIDR](https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing). Return a tuple with two IPv4 containing the lower range and the higher range of the subnet.
+
+``` sql
+SELECT IPv4CIDRToRange(toIPv4('192.168.5.2'), 16);
+```
+
+``` text
+┌─IPv4CIDRToRange(toIPv4('192.168.5.2'), 16)─┐
+│ ('192.168.0.0','192.168.255.255')          │
+└────────────────────────────────────────────┘
+```
+
+## IPv6CIDRToRange(ipv6, Cidr), {#ipv6cidrtorangeipv6-cidr}
+
+Accepts an IPv6 and an UInt8 value containing the CIDR. Return a tuple with two IPv6 containing the lower range and the higher range of the subnet.
+
+``` sql
+SELECT IPv6CIDRToRange(toIPv6('2001:0db8:0000:85a3:0000:0000:ac1f:8001'), 32);
+```
+
+``` text
+┌─IPv6CIDRToRange(toIPv6('2001:0db8:0000:85a3:0000:0000:ac1f:8001'), 32)─┐
+│ ('2001:db8::','2001:db8:ffff:ffff:ffff:ffff:ffff:ffff')                │
+└────────────────────────────────────────────────────────────────────────┘
+```
+
+## toIPv4(string) {#toipv4string}
+
+An alias to `IPv4StringToNum()` that takes a string form of IPv4 address and returns value of [IPv4](../../sql-reference/data-types/domains/ipv4.md) type, which is binary equal to value returned by `IPv4StringToNum()`.
+
+``` sql
+WITH
+    '171.225.130.45' as IPv4_string
+SELECT
+    toTypeName(IPv4StringToNum(IPv4_string)),
+    toTypeName(toIPv4(IPv4_string))
+```
+
+``` text
+┌─toTypeName(IPv4StringToNum(IPv4_string))─┬─toTypeName(toIPv4(IPv4_string))─┐
+│ UInt32                                   │ IPv4                            │
+└──────────────────────────────────────────┴─────────────────────────────────┘
+```
+
+``` sql
+WITH
+    '171.225.130.45' as IPv4_string
+SELECT
+    hex(IPv4StringToNum(IPv4_string)),
+    hex(toIPv4(IPv4_string))
+```
+
+``` text
+┌─hex(IPv4StringToNum(IPv4_string))─┬─hex(toIPv4(IPv4_string))─┐
+│ ABE1822D                          │ ABE1822D                 │
+└───────────────────────────────────┴──────────────────────────┘
+```
+
+## toIPv6 {#toipv6string}
+
+Converts a string form of IPv6 address to [IPv6](../../sql-reference/data-types/domains/ipv6.md) type. If the IPv6 address has an invalid format, returns an empty value.
+Similar to [IPv6StringToNum](#ipv6stringtonums) function, which converts IPv6 address to binary format.
+
+If the input string contains a valid IPv4 address, then the IPv6 equivalent of the IPv4 address is returned.
+
+**Syntax**
+
+```sql
+toIPv6(string)
+```
+
+**Argument**
+
+-   `string` — IP address. [String](../../sql-reference/data-types/string.md)
+
+**Returned value**
+
+-   IP address.
+
+Type: [IPv6](../../sql-reference/data-types/domains/ipv6.md).
+
+**Examples**
+
+Query:
+
+``` sql
+WITH '2001:438:ffff::407d:1bc1' AS IPv6_string
+SELECT
+    hex(IPv6StringToNum(IPv6_string)),
+    hex(toIPv6(IPv6_string));
+```
+
+Result:
+
+``` text
+┌─hex(IPv6StringToNum(IPv6_string))─┬─hex(toIPv6(IPv6_string))─────────┐
+│ 20010438FFFF000000000000407D1BC1  │ 20010438FFFF000000000000407D1BC1 │
+└───────────────────────────────────┴──────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT toIPv6('127.0.0.1');
+```
+
+Result:
+
+``` text
+┌─toIPv6('127.0.0.1')─┐
+│ ::ffff:127.0.0.1    │
+└─────────────────────┘
+```
+
+## isIPv4String {#isipv4string}
+
+Determines whether the input string is an IPv4 address or not. If `string` is IPv6 address returns `0`.
+
+**Syntax**
+
+```sql
+isIPv4String(string)
+```
+
+**Arguments**
+
+-   `string` — IP address. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   `1` if `string` is IPv4 address, `0` otherwise.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+Query:
+
+```sql
+SELECT addr, isIPv4String(addr) FROM ( SELECT ['0.0.0.0', '127.0.0.1', '::ffff:127.0.0.1'] AS addr ) ARRAY JOIN addr;
+```
+
+Result:
+
+``` text
+┌─addr─────────────┬─isIPv4String(addr)─┐
+│ 0.0.0.0          │                  1 │
+│ 127.0.0.1        │                  1 │
+│ ::ffff:127.0.0.1 │                  0 │
+└──────────────────┴────────────────────┘
+```
+
+## isIPv6String {#isipv6string}
+
+Determines whether the input string is an IPv6 address or not. If `string` is IPv4 address returns `0`.
+
+**Syntax**
+
+```sql
+isIPv6String(string)
+```
+
+**Arguments**
+
+-   `string` — IP address. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   `1` if `string` is IPv6 address, `0` otherwise.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT addr, isIPv6String(addr) FROM ( SELECT ['::', '1111::ffff', '::ffff:127.0.0.1', '127.0.0.1'] AS addr ) ARRAY JOIN addr;
+```
+
+Result:
+
+``` text
+┌─addr─────────────┬─isIPv6String(addr)─┐
+│ ::               │                  1 │
+│ 1111::ffff       │                  1 │
+│ ::ffff:127.0.0.1 │                  1 │
+│ 127.0.0.1        │                  0 │
+└──────────────────┴────────────────────┘
+```
+
+## isIPAddressInRange {#isipaddressinrange}
+
+Determines if an IP address is contained in a network represented in the [CIDR](https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing) notation. Returns `1` if true, or `0` otherwise.
+
+**Syntax**
+
+``` sql
+isIPAddressInRange(address, prefix)
+```
+
+This function accepts both IPv4 and IPv6 addresses (and networks) represented as strings. It returns `0` if the IP version of the address and the CIDR don't match.
+
+**Arguments**
+
+-   `address` — An IPv4 or IPv6 address. [String](../../sql-reference/data-types/string.md).
+-   `prefix` — An IPv4 or IPv6 network prefix in CIDR. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   `1` or `0`.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT isIPAddressInRange('127.0.0.1', '127.0.0.0/8');
+```
+
+Result:
+
+``` text
+┌─isIPAddressInRange('127.0.0.1', '127.0.0.0/8')─┐
+│                                              1 │
+└────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT isIPAddressInRange('127.0.0.1', 'ffff::/16');
+```
+
+Result:
+
+``` text
+┌─isIPAddressInRange('127.0.0.1', 'ffff::/16')─┐
+│                                            0 │
+└──────────────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/json-functions.md b/docs/en/reference/sql-reference/functions/json-functions.md
new file mode 100644
index 00000000000..be69b7b4f2b
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/json-functions.md
@@ -0,0 +1,466 @@
+---
+sidebar_position: 56
+sidebar_label: JSON
+---
+
+# Functions for Working with JSON {#functions-for-working-with-json}
+
+ClickHouse has special functions for working with this JSON. All the JSON functions are based on strong assumptions about what the JSON can be, but they try to do as little as possible to get the job done.
+
+The following assumptions are made:
+
+1.  The field name (function argument) must be a constant.
+2.  The field name is somehow canonically encoded in JSON. For example: `visitParamHas('{"abc":"def"}', 'abc') = 1`, but `visitParamHas('{"\\u0061\\u0062\\u0063":"def"}', 'abc') = 0`
+3.  Fields are searched for on any nesting level, indiscriminately. If there are multiple matching fields, the first occurrence is used.
+4.  The JSON does not have space characters outside of string literals.
+
+## visitParamHas(params, name) {#visitparamhasparams-name}
+
+Checks whether there is a field with the `name` name.
+
+Alias: `simpleJSONHas`.
+
+## visitParamExtractUInt(params, name) {#visitparamextractuintparams-name}
+
+Parses UInt64 from the value of the field named `name`. If this is a string field, it tries to parse a number from the beginning of the string. If the field does not exist, or it exists but does not contain a number, it returns 0.
+
+Alias: `simpleJSONExtractUInt`.
+
+## visitParamExtractInt(params, name) {#visitparamextractintparams-name}
+
+The same as for Int64.
+
+Alias: `simpleJSONExtractInt`.
+
+## visitParamExtractFloat(params, name) {#visitparamextractfloatparams-name}
+
+The same as for Float64.
+
+Alias: `simpleJSONExtractFloat`.
+
+## visitParamExtractBool(params, name) {#visitparamextractboolparams-name}
+
+Parses a true/false value. The result is UInt8.
+
+Alias: `simpleJSONExtractBool`.
+
+## visitParamExtractRaw(params, name) {#visitparamextractrawparams-name}
+
+Returns the value of a field, including separators.
+
+Alias: `simpleJSONExtractRaw`.
+
+Examples:
+
+``` sql
+visitParamExtractRaw('{"abc":"\\n\\u0000"}', 'abc') = '"\\n\\u0000"';
+visitParamExtractRaw('{"abc":{"def":[1,2,3]}}', 'abc') = '{"def":[1,2,3]}';
+```
+
+## visitParamExtractString(params, name) {#visitparamextractstringparams-name}
+
+Parses the string in double quotes. The value is unescaped. If unescaping failed, it returns an empty string.
+
+Alias: `simpleJSONExtractString`.
+
+Examples:
+
+``` sql
+visitParamExtractString('{"abc":"\\n\\u0000"}', 'abc') = '\n\0';
+visitParamExtractString('{"abc":"\\u263a"}', 'abc') = '☺';
+visitParamExtractString('{"abc":"\\u263"}', 'abc') = '';
+visitParamExtractString('{"abc":"hello}', 'abc') = '';
+```
+
+There is currently no support for code points in the format `\uXXXX\uYYYY` that are not from the basic multilingual plane (they are converted to CESU-8 instead of UTF-8).
+
+The following functions are based on [simdjson](https://github.com/lemire/simdjson) designed for more complex JSON parsing requirements. The assumption 2 mentioned above still applies.
+
+## isValidJSON(json) {#isvalidjsonjson}
+
+Checks that passed string is a valid json.
+
+Examples:
+
+``` sql
+SELECT isValidJSON('{"a": "hello", "b": [-100, 200.0, 300]}') = 1
+SELECT isValidJSON('not a json') = 0
+```
+
+## JSONHas(json\[, indices_or_keys\]…) {#jsonhasjson-indices-or-keys}
+
+If the value exists in the JSON document, `1` will be returned.
+
+If the value does not exist, `0` will be returned.
+
+Examples:
+
+``` sql
+SELECT JSONHas('{"a": "hello", "b": [-100, 200.0, 300]}', 'b') = 1
+SELECT JSONHas('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 4) = 0
+```
+
+`indices_or_keys` is a list of zero or more arguments each of them can be either string or integer.
+
+-   String = access object member by key.
+-   Positive integer = access the n-th member/key from the beginning.
+-   Negative integer = access the n-th member/key from the end.
+
+Minimum index of the element is 1. Thus the element 0 does not exist.
+
+You may use integers to access both JSON arrays and JSON objects.
+
+So, for example:
+
+``` sql
+SELECT JSONExtractKey('{"a": "hello", "b": [-100, 200.0, 300]}', 1) = 'a'
+SELECT JSONExtractKey('{"a": "hello", "b": [-100, 200.0, 300]}', 2) = 'b'
+SELECT JSONExtractKey('{"a": "hello", "b": [-100, 200.0, 300]}', -1) = 'b'
+SELECT JSONExtractKey('{"a": "hello", "b": [-100, 200.0, 300]}', -2) = 'a'
+SELECT JSONExtractString('{"a": "hello", "b": [-100, 200.0, 300]}', 1) = 'hello'
+```
+
+## JSONLength(json\[, indices_or_keys\]…) {#jsonlengthjson-indices-or-keys}
+
+Return the length of a JSON array or a JSON object.
+
+If the value does not exist or has a wrong type, `0` will be returned.
+
+Examples:
+
+``` sql
+SELECT JSONLength('{"a": "hello", "b": [-100, 200.0, 300]}', 'b') = 3
+SELECT JSONLength('{"a": "hello", "b": [-100, 200.0, 300]}') = 2
+```
+
+## JSONType(json\[, indices_or_keys\]…) {#jsontypejson-indices-or-keys}
+
+Return the type of a JSON value.
+
+If the value does not exist, `Null` will be returned.
+
+Examples:
+
+``` sql
+SELECT JSONType('{"a": "hello", "b": [-100, 200.0, 300]}') = 'Object'
+SELECT JSONType('{"a": "hello", "b": [-100, 200.0, 300]}', 'a') = 'String'
+SELECT JSONType('{"a": "hello", "b": [-100, 200.0, 300]}', 'b') = 'Array'
+```
+
+## JSONExtractUInt(json\[, indices_or_keys\]…) {#jsonextractuintjson-indices-or-keys}
+
+## JSONExtractInt(json\[, indices_or_keys\]…) {#jsonextractintjson-indices-or-keys}
+
+## JSONExtractFloat(json\[, indices_or_keys\]…) {#jsonextractfloatjson-indices-or-keys}
+
+## JSONExtractBool(json\[, indices_or_keys\]…) {#jsonextractbooljson-indices-or-keys}
+
+Parses a JSON and extract a value. These functions are similar to `visitParam` functions.
+
+If the value does not exist or has a wrong type, `0` will be returned.
+
+Examples:
+
+``` sql
+SELECT JSONExtractInt('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 1) = -100
+SELECT JSONExtractFloat('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 2) = 200.0
+SELECT JSONExtractUInt('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', -1) = 300
+```
+
+## JSONExtractString(json\[, indices_or_keys\]…) {#jsonextractstringjson-indices-or-keys}
+
+Parses a JSON and extract a string. This function is similar to `visitParamExtractString` functions.
+
+If the value does not exist or has a wrong type, an empty string will be returned.
+
+The value is unescaped. If unescaping failed, it returns an empty string.
+
+Examples:
+
+``` sql
+SELECT JSONExtractString('{"a": "hello", "b": [-100, 200.0, 300]}', 'a') = 'hello'
+SELECT JSONExtractString('{"abc":"\\n\\u0000"}', 'abc') = '\n\0'
+SELECT JSONExtractString('{"abc":"\\u263a"}', 'abc') = '☺'
+SELECT JSONExtractString('{"abc":"\\u263"}', 'abc') = ''
+SELECT JSONExtractString('{"abc":"hello}', 'abc') = ''
+```
+
+## JSONExtract(json\[, indices_or_keys…\], Return_type) {#jsonextractjson-indices-or-keys-return-type}
+
+Parses a JSON and extract a value of the given ClickHouse data type.
+
+This is a generalization of the previous `JSONExtract<type>` functions.
+This means
+`JSONExtract(..., 'String')` returns exactly the same as `JSONExtractString()`,
+`JSONExtract(..., 'Float64')` returns exactly the same as `JSONExtractFloat()`.
+
+Examples:
+
+``` sql
+SELECT JSONExtract('{"a": "hello", "b": [-100, 200.0, 300]}', 'Tuple(String, Array(Float64))') = ('hello',[-100,200,300])
+SELECT JSONExtract('{"a": "hello", "b": [-100, 200.0, 300]}', 'Tuple(b Array(Float64), a String)') = ([-100,200,300],'hello')
+SELECT JSONExtract('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 'Array(Nullable(Int8))') = [-100, NULL, NULL]
+SELECT JSONExtract('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 4, 'Nullable(Int64)') = NULL
+SELECT JSONExtract('{"passed": true}', 'passed', 'UInt8') = 1
+SELECT JSONExtract('{"day": "Thursday"}', 'day', 'Enum8(\'Sunday\' = 0, \'Monday\' = 1, \'Tuesday\' = 2, \'Wednesday\' = 3, \'Thursday\' = 4, \'Friday\' = 5, \'Saturday\' = 6)') = 'Thursday'
+SELECT JSONExtract('{"day": 5}', 'day', 'Enum8(\'Sunday\' = 0, \'Monday\' = 1, \'Tuesday\' = 2, \'Wednesday\' = 3, \'Thursday\' = 4, \'Friday\' = 5, \'Saturday\' = 6)') = 'Friday'
+```
+
+## JSONExtractKeysAndValues(json\[, indices_or_keys…\], Value_type) {#jsonextractkeysandvaluesjson-indices-or-keys-value-type}
+
+Parses key-value pairs from a JSON where the values are of the given ClickHouse data type.
+
+Example:
+
+``` sql
+SELECT JSONExtractKeysAndValues('{"x": {"a": 5, "b": 7, "c": 11}}', 'x', 'Int8') = [('a',5),('b',7),('c',11)];
+```
+
+## JSONExtractKeys {#jsonextractkeysjson-indices-or-keys}
+
+Parses a JSON string and extracts the keys.
+
+**Syntax**
+
+``` sql
+JSONExtractKeys(json[, a, b, c...])
+```
+
+**Arguments**
+
+-   `json` — [String](../../sql-reference/data-types/string.md) with valid JSON.
+-   `a, b, c...` — Comma-separated indices or keys that specify the path to the inner field in a nested JSON object. Each argument can be either a [String](../../sql-reference/data-types/string.md) to get the field by the key or an [Integer](../../sql-reference/data-types/int-uint.md) to get the N-th field (indexed from 1, negative integers count from the end). If not set, the whole JSON is parsed as the top-level object. Optional parameter.
+
+**Returned value**
+
+Array with the keys of the JSON.
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+**Example**
+
+Query:
+
+```sql
+SELECT JSONExtractKeys('{"a": "hello", "b": [-100, 200.0, 300]}');
+```
+
+Result:
+
+```
+text
+┌─JSONExtractKeys('{"a": "hello", "b": [-100, 200.0, 300]}')─┐
+│ ['a','b']                                                  │
+└────────────────────────────────────────────────────────────┘
+```
+
+## JSONExtractRaw(json\[, indices_or_keys\]…) {#jsonextractrawjson-indices-or-keys}
+
+Returns a part of JSON as unparsed string.
+
+If the part does not exist or has a wrong type, an empty string will be returned.
+
+Example:
+
+``` sql
+SELECT JSONExtractRaw('{"a": "hello", "b": [-100, 200.0, 300]}', 'b') = '[-100, 200.0, 300]';
+```
+
+## JSONExtractArrayRaw(json\[, indices_or_keys…\]) {#jsonextractarrayrawjson-indices-or-keys}
+
+Returns an array with elements of JSON array, each represented as unparsed string.
+
+If the part does not exist or isn’t array, an empty array will be returned.
+
+Example:
+
+``` sql
+SELECT JSONExtractArrayRaw('{"a": "hello", "b": [-100, 200.0, "hello"]}', 'b') = ['-100', '200.0', '"hello"'];
+```
+
+## JSONExtractKeysAndValuesRaw {#json-extract-keys-and-values-raw}
+
+Extracts raw data from a JSON object.
+
+**Syntax**
+
+``` sql
+JSONExtractKeysAndValuesRaw(json[, p, a, t, h])
+```
+
+**Arguments**
+
+-   `json` — [String](../../sql-reference/data-types/string.md) with valid JSON.
+-   `p, a, t, h` — Comma-separated indices or keys that specify the path to the inner field in a nested JSON object. Each argument can be either a [string](../../sql-reference/data-types/string.md) to get the field by the key or an [integer](../../sql-reference/data-types/int-uint.md) to get the N-th field (indexed from 1, negative integers count from the end). If not set, the whole JSON is parsed as the top-level object. Optional parameter.
+
+**Returned values**
+
+-   Array with `('key', 'value')` tuples. Both tuple members are strings.
+-   Empty array if the requested object does not exist, or input JSON is invalid.
+
+Type: [Array](../../sql-reference/data-types/array.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md), [String](../../sql-reference/data-types/string.md)).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}');
+```
+
+Result:
+
+``` text
+┌─JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}')─┐
+│ [('a','[-100,200]'),('b','{"c":{"d":"hello","f":"world"}}')]                                 │
+└──────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}', 'b');
+```
+
+Result:
+
+``` text
+┌─JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}', 'b')─┐
+│ [('c','{"d":"hello","f":"world"}')]                                                               │
+└───────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}', -1, 'c');
+```
+
+Result:
+
+``` text
+┌─JSONExtractKeysAndValuesRaw('{"a": [-100, 200.0], "b":{"c": {"d": "hello", "f": "world"}}}', -1, 'c')─┐
+│ [('d','"hello"'),('f','"world"')]                                                                     │
+└───────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+## JSON_EXISTS(json, path) {#json-exists}
+
+If the value exists in the JSON document, `1` will be returned.
+
+If the value does not exist, `0` will be returned.
+
+Examples:
+
+``` sql
+SELECT JSON_EXISTS('{"hello":1}', '$.hello');
+SELECT JSON_EXISTS('{"hello":{"world":1}}', '$.hello.world');
+SELECT JSON_EXISTS('{"hello":["world"]}', '$.hello[*]');
+SELECT JSON_EXISTS('{"hello":["world"]}', '$.hello[0]');
+```
+
+:::note    
+Before version 21.11 the order of arguments was wrong, i.e. JSON_EXISTS(path, json)
+:::
+
+## JSON_QUERY(json, path) {#json-query}
+
+Parses a JSON and extract a value as JSON array or JSON object.
+
+If the value does not exist, an empty string will be returned.
+
+Example:
+
+``` sql
+SELECT JSON_QUERY('{"hello":"world"}', '$.hello');
+SELECT JSON_QUERY('{"array":[[0, 1, 2, 3, 4, 5], [0, -1, -2, -3, -4, -5]]}', '$.array[*][0 to 2, 4]');
+SELECT JSON_QUERY('{"hello":2}', '$.hello');
+SELECT toTypeName(JSON_QUERY('{"hello":2}', '$.hello'));
+```
+
+Result:
+
+``` text
+["world"]
+[0, 1, 4, 0, -1, -4]
+[2]
+String
+```
+:::note    
+Before version 21.11 the order of arguments was wrong, i.e. JSON_QUERY(path, json)
+:::
+
+## JSON_VALUE(json, path) {#json-value}
+
+Parses a JSON and extract a value as JSON scalar.
+
+If the value does not exist, an empty string will be returned.
+
+Example:
+
+``` sql
+SELECT JSON_VALUE('{"hello":"world"}', '$.hello');
+SELECT JSON_VALUE('{"array":[[0, 1, 2, 3, 4, 5], [0, -1, -2, -3, -4, -5]]}', '$.array[*][0 to 2, 4]');
+SELECT JSON_VALUE('{"hello":2}', '$.hello');
+SELECT toTypeName(JSON_VALUE('{"hello":2}', '$.hello'));
+```
+
+Result:
+
+``` text
+"world"
+0
+2
+String
+```
+
+:::note    
+Before version 21.11 the order of arguments was wrong, i.e. JSON_VALUE(path, json)
+:::
+
+## toJSONString {#tojsonstring}
+
+Serializes a value to its JSON representation. Various data types and nested structures are supported.
+64-bit [integers](../../sql-reference/data-types/int-uint.md) or bigger (like `UInt64` or `Int128`) are enclosed in quotes by default. [output_format_json_quote_64bit_integers](../../operations/settings/settings.md#session_settings-output_format_json_quote_64bit_integers) controls this behavior.
+Special values `NaN` and `inf` are replaced with `null`. Enable [output_format_json_quote_denormals](../../operations/settings/settings.md#settings-output_format_json_quote_denormals) setting to show them.
+When serializing an [Enum](../../sql-reference/data-types/enum.md) value, the function outputs its name.
+
+**Syntax**
+
+``` sql
+toJSONString(value)
+```
+
+**Arguments**
+
+-   `value` — Value to serialize. Value may be of any data type.
+
+**Returned value**
+
+-   JSON representation of the value.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+The first example shows serialization of a [Map](../../sql-reference/data-types/map.md).
+The second example shows some special values wrapped into a [Tuple](../../sql-reference/data-types/tuple.md).
+
+Query:
+
+``` sql
+SELECT toJSONString(map('key1', 1, 'key2', 2));
+SELECT toJSONString(tuple(1.25, NULL, NaN, +inf, -inf, [])) SETTINGS output_format_json_quote_denormals = 1;
+```
+
+Result:
+
+``` text
+{"key1":1,"key2":2}
+[1.25,null,"nan","inf","-inf",[]]
+```
+
+**See Also**
+
+-   [output_format_json_quote_64bit_integers](../../operations/settings/settings.md#session_settings-output_format_json_quote_64bit_integers)
+-   [output_format_json_quote_denormals](../../operations/settings/settings.md#settings-output_format_json_quote_denormals)
diff --git a/docs/en/reference/sql-reference/functions/logical-functions.md b/docs/en/reference/sql-reference/functions/logical-functions.md
new file mode 100644
index 00000000000..0055e253951
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/logical-functions.md
@@ -0,0 +1,194 @@
+---
+sidebar_position: 37
+sidebar_label: Logical
+---
+
+# Logical Functions {#logical-functions}
+
+Performs logical operations on arguments of any numeric types, but returns a [UInt8](../../sql-reference/data-types/int-uint.md) number equal to 0, 1 or `NULL` in some cases.
+
+Zero as an argument is considered `false`, while any non-zero value is considered `true`.
+
+## and {#logical-and-function}
+
+Calculates the result of the logical conjunction between two or more values. Corresponds to [Logical AND Operator](../../sql-reference/operators/index.md#logical-and-operator).
+
+**Syntax**
+
+``` sql
+and(val1, val2...)
+```
+
+You can use the [short_circuit_function_evaluation](../../operations/settings/settings.md#short-circuit-function-evaluation) setting to calculate the `and` function according to a short scheme. If this setting is enabled, `vali` is evaluated only on rows where `(val1 AND val2 AND ... AND val{i-1})` is true. For example, an exception about division by zero is not thrown when executing the query `SELECT and(number = 2, intDiv(1, number)) FROM numbers(10)`.
+
+**Arguments**
+
+-   `val1, val2, ...` — List of at least two values. [Int](../../sql-reference/data-types/int-uint.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Nullable](../../sql-reference/data-types/nullable.md).
+
+**Returned value**
+
+-   `0`, if there is at least one zero value argument.
+-   `NULL`, if there are no zero values arguments and there is at least one `NULL` argument.
+-   `1`, otherwise.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md) or [Nullable](../../sql-reference/data-types/nullable.md)([UInt8](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT and(0, 1, -2);
+```
+
+Result:
+
+``` text
+┌─and(0, 1, -2)─┐
+│             0 │
+└───────────────┘
+```
+
+With `NULL`:
+
+``` sql
+SELECT and(NULL, 1, 10, -2);
+```
+
+Result:
+
+``` text
+┌─and(NULL, 1, 10, -2)─┐
+│                 ᴺᵁᴸᴸ │
+└──────────────────────┘
+```
+
+## or {#logical-or-function}
+
+Calculates the result of the logical disjunction between two or more values. Corresponds to [Logical OR Operator](../../sql-reference/operators/index.md#logical-or-operator).
+
+**Syntax**
+
+``` sql
+or(val1, val2...)
+```
+
+You can use the [short_circuit_function_evaluation](../../operations/settings/settings.md#short-circuit-function-evaluation) setting to calculate the `or` function according to a short scheme. If this setting is enabled, `vali` is evaluated only on rows where `((NOT val1) AND (NOT val2) AND ... AND (NOT val{i-1}))` is true. For example, an exception about division by zero is not thrown when executing the query `SELECT or(number = 0, intDiv(1, number) != 0) FROM numbers(10)`.
+
+**Arguments**
+
+-   `val1, val2, ...` — List of at least two values. [Int](../../sql-reference/data-types/int-uint.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Nullable](../../sql-reference/data-types/nullable.md).
+
+**Returned value**
+
+-   `1`, if there is at least one non-zero value.
+-   `0`, if there are only zero values.
+-   `NULL`, if there are only zero values and `NULL`.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md) or [Nullable](../../sql-reference/data-types/nullable.md)([UInt8](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT or(1, 0, 0, 2, NULL);
+```
+
+Result:
+
+``` text
+┌─or(1, 0, 0, 2, NULL)─┐
+│                    1 │
+└──────────────────────┘
+```
+
+With `NULL`:
+
+``` sql
+SELECT or(0, NULL);
+```
+
+Result:
+
+``` text
+┌─or(0, NULL)─┐
+│        ᴺᵁᴸᴸ │
+└─────────────┘
+```
+
+## not {#logical-not-function}
+
+Calculates the result of the logical negation of the value. Corresponds to [Logical Negation Operator](../../sql-reference/operators/index.md#logical-negation-operator).
+
+**Syntax**
+
+``` sql
+not(val);
+```
+
+**Arguments**
+
+-   `val` — The value. [Int](../../sql-reference/data-types/int-uint.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Nullable](../../sql-reference/data-types/nullable.md).
+
+**Returned value**
+
+-   `1`, if the `val` is `0`.
+-   `0`, if the `val` is a non-zero value.
+-   `NULL`, if the `val` is a `NULL` value.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md) or [Nullable](../../sql-reference/data-types/nullable.md)([UInt8](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT NOT(1);
+```
+
+Result:
+
+``` test
+┌─not(1)─┐
+│      0 │
+└────────┘
+```
+
+## xor {#logical-xor-function}
+
+Calculates the result of the logical exclusive disjunction between two or more values. For more than two values the function works as if it calculates `XOR` of the first two values and then uses the result with the next value to calculate `XOR` and so on.
+
+**Syntax**
+
+``` sql
+xor(val1, val2...)
+```
+
+**Arguments**
+
+-   `val1, val2, ...` — List of at least two values. [Int](../../sql-reference/data-types/int-uint.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Nullable](../../sql-reference/data-types/nullable.md).
+
+**Returned value**
+
+-   `1`, for two values: if one of the values is zero and other is not.
+-   `0`, for two values: if both values are zero or non-zero at the same time.
+-   `NULL`, if there is at least one `NULL` value.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md) or [Nullable](../../sql-reference/data-types/nullable.md)([UInt8](../../sql-reference/data-types/int-uint.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT xor(0, 1, 1);
+```
+
+Result:
+
+``` text
+┌─xor(0, 1, 1)─┐
+│            0 │
+└──────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/machine-learning-functions.md b/docs/en/reference/sql-reference/functions/machine-learning-functions.md
new file mode 100644
index 00000000000..5b3e8b87e34
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/machine-learning-functions.md
@@ -0,0 +1,18 @@
+---
+sidebar_position: 64
+sidebar_label: Machine Learning
+---
+
+# Machine Learning Functions {#machine-learning-functions}
+
+## evalMLMethod {#machine_learning_methods-evalmlmethod}
+
+Prediction using fitted regression models uses `evalMLMethod` function. See link in `linearRegression`.
+
+## stochasticLinearRegression {#stochastic-linear-regression}
+
+The [stochasticLinearRegression](../../sql-reference/aggregate-functions/reference/stochasticlinearregression.md#agg_functions-stochasticlinearregression) aggregate function implements stochastic gradient descent method using linear model and MSE loss function. Uses `evalMLMethod` to predict on new data.
+
+## stochasticLogisticRegression {#stochastic-logistic-regression}
+
+The [stochasticLogisticRegression](../../sql-reference/aggregate-functions/reference/stochasticlogisticregression.md#agg_functions-stochasticlogisticregression) aggregate function implements stochastic gradient descent method for binary classification problem. Uses `evalMLMethod` to predict on new data.
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/functions/math-functions.md b/docs/en/reference/sql-reference/functions/math-functions.md
new file mode 100644
index 00000000000..645587b4f5c
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/math-functions.md
@@ -0,0 +1,550 @@
+---
+sidebar_position: 44
+sidebar_label: Mathematical
+---
+
+# Mathematical Functions {#mathematical-functions}
+
+All the functions return a Float64 number. The accuracy of the result is close to the maximum precision possible, but the result might not coincide with the machine representable number nearest to the corresponding real number.
+
+## e() {#e}
+
+Returns a Float64 number that is close to the number e.
+
+## pi() {#pi}
+
+Returns a Float64 number that is close to the number π.
+
+## exp(x) {#expx}
+
+Accepts a numeric argument and returns a Float64 number close to the exponent of the argument.
+
+## log(x), ln(x) {#logx-lnx}
+
+Accepts a numeric argument and returns a Float64 number close to the natural logarithm of the argument.
+
+## exp2(x) {#exp2x}
+
+Accepts a numeric argument and returns a Float64 number close to 2 to the power of x.
+
+## log2(x) {#log2x}
+
+Accepts a numeric argument and returns a Float64 number close to the binary logarithm of the argument.
+
+## exp10(x) {#exp10x}
+
+Accepts a numeric argument and returns a Float64 number close to 10 to the power of x.
+
+## log10(x) {#log10x}
+
+Accepts a numeric argument and returns a Float64 number close to the decimal logarithm of the argument.
+
+## sqrt(x) {#sqrtx}
+
+Accepts a numeric argument and returns a Float64 number close to the square root of the argument.
+
+## cbrt(x) {#cbrtx}
+
+Accepts a numeric argument and returns a Float64 number close to the cubic root of the argument.
+
+## erf(x) {#erfx}
+
+If ‘x’ is non-negative, then `erf(x / σ√2)` is the probability that a random variable having a normal distribution with standard deviation ‘σ’ takes the value that is separated from the expected value by more than ‘x’.
+
+Example (three sigma rule):
+
+``` sql
+SELECT erf(3 / sqrt(2));
+```
+
+``` text
+┌─erf(divide(3, sqrt(2)))─┐
+│      0.9973002039367398 │
+└─────────────────────────┘
+```
+
+## erfc(x) {#erfcx}
+
+Accepts a numeric argument and returns a Float64 number close to 1 - erf(x), but without loss of precision for large ‘x’ values.
+
+## lgamma(x) {#lgammax}
+
+The logarithm of the gamma function.
+
+## tgamma(x) {#tgammax}
+
+Gamma function.
+
+## sin(x) {#sinx}
+
+The sine.
+
+## cos(x) {#cosx}
+
+The cosine.
+
+## tan(x) {#tanx}
+
+The tangent.
+
+## asin(x) {#asinx}
+
+The arc sine.
+
+## acos(x) {#acosx}
+
+The arc cosine.
+
+## atan(x) {#atanx}
+
+The arc tangent.
+
+## pow(x, y), power(x, y) {#powx-y-powerx-y}
+
+Takes two numeric arguments x and y. Returns a Float64 number close to x to the power of y.
+
+## intExp2 {#intexp2}
+
+Accepts a numeric argument and returns a UInt64 number close to 2 to the power of x.
+
+## intExp10 {#intexp10}
+
+Accepts a numeric argument and returns a UInt64 number close to 10 to the power of x.
+
+## cosh(x) {#coshx}
+
+[Hyperbolic cosine](https://in.mathworks.com/help/matlab/ref/cosh.html).
+
+**Syntax**
+
+``` sql
+cosh(x)
+```
+
+**Arguments**
+
+-   `x` — The angle, in radians. Values from the interval: `-∞ < x < +∞`. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   Values from the interval: `1 <= cosh(x) < +∞`.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT cosh(0);
+```
+
+Result:
+
+``` text
+┌─cosh(0)──┐
+│        1 │
+└──────────┘
+```
+
+## acosh(x) {#acoshx}
+
+[Inverse hyperbolic cosine](https://www.mathworks.com/help/matlab/ref/acosh.html).
+
+**Syntax**
+
+``` sql
+acosh(x)
+```
+
+**Arguments**
+
+-   `x` — Hyperbolic cosine of angle. Values from the interval: `1 <= x < +∞`. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   The angle, in radians. Values from the interval: `0 <= acosh(x) < +∞`.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT acosh(1);
+```
+
+Result:
+
+``` text
+┌─acosh(1)─┐
+│        0 │
+└──────────┘
+```
+
+**See Also**
+
+-   [cosh(x)](../../sql-reference/functions/math-functions.md#coshx)
+
+## sinh(x) {#sinhx}
+
+[Hyperbolic sine](https://www.mathworks.com/help/matlab/ref/sinh.html).
+
+**Syntax**
+
+``` sql
+sinh(x)
+```
+
+**Arguments**
+
+-   `x` — The angle, in radians. Values from the interval: `-∞ < x < +∞`. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   Values from the interval: `-∞ < sinh(x) < +∞`.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT sinh(0);
+```
+
+Result:
+
+``` text
+┌─sinh(0)──┐
+│        0 │
+└──────────┘
+```
+
+## asinh(x) {#asinhx}
+
+[Inverse hyperbolic sine](https://www.mathworks.com/help/matlab/ref/asinh.html).
+
+**Syntax**
+
+``` sql
+asinh(x)
+```
+
+**Arguments**
+
+-   `x` — Hyperbolic sine of angle. Values from the interval: `-∞ < x < +∞`. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   The angle, in radians. Values from the interval: `-∞ < asinh(x) < +∞`.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT asinh(0);
+```
+
+Result:
+
+``` text
+┌─asinh(0)─┐
+│        0 │
+└──────────┘
+```
+
+**See Also**
+
+-   [sinh(x)](../../sql-reference/functions/math-functions.md#sinhx)
+
+## atanh(x) {#atanhx}
+
+[Inverse hyperbolic tangent](https://www.mathworks.com/help/matlab/ref/atanh.html).
+
+**Syntax**
+
+``` sql
+atanh(x)
+```
+
+**Arguments**
+
+-   `x` — Hyperbolic tangent of angle. Values from the interval: `–1 < x < 1`. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   The angle, in radians. Values from the interval: `-∞ < atanh(x) < +∞`.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT atanh(0);
+```
+
+Result:
+
+``` text
+┌─atanh(0)─┐
+│        0 │
+└──────────┘
+```
+
+## atan2(y, x) {#atan2yx}
+
+The [function](https://en.wikipedia.org/wiki/Atan2) calculates the angle in the Euclidean plane, given in radians, between the positive x axis and the ray to the point `(x, y) ≠ (0, 0)`.
+
+**Syntax**
+
+``` sql
+atan2(y, x)
+```
+
+**Arguments**
+
+-   `y` — y-coordinate of the point through which the ray passes. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+-   `x` — x-coordinate of the point through which the ray passes. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   The angle `θ` such that `−π < θ ≤ π`, in radians.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT atan2(1, 1);
+```
+
+Result:
+
+``` text
+┌────────atan2(1, 1)─┐
+│ 0.7853981633974483 │
+└────────────────────┘
+```
+
+## hypot(x, y) {#hypotxy}
+
+Calculates the length of the hypotenuse of a right-angle triangle. The [function](https://en.wikipedia.org/wiki/Hypot) avoids problems that occur when squaring very large or very small numbers.
+
+**Syntax**
+
+``` sql
+hypot(x, y)
+```
+
+**Arguments**
+
+-   `x` — The first cathetus of a right-angle triangle. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+-   `y` — The second cathetus of a right-angle triangle. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   The length of the hypotenuse of a right-angle triangle.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT hypot(1, 1);
+```
+
+Result:
+
+``` text
+┌────────hypot(1, 1)─┐
+│ 1.4142135623730951 │
+└────────────────────┘
+```
+
+## log1p(x) {#log1px}
+
+Calculates `log(1+x)`. The [function](https://en.wikipedia.org/wiki/Natural_logarithm#lnp1) `log1p(x)` is more accurate than `log(1+x)` for small values of x.
+
+**Syntax**
+
+``` sql
+log1p(x)
+```
+
+**Arguments**
+
+-   `x` — Values from the interval: `-1 < x < +∞`. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   Values from the interval: `-∞ < log1p(x) < +∞`.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT log1p(0);
+```
+
+Result:
+
+``` text
+┌─log1p(0)─┐
+│        0 │
+└──────────┘
+```
+
+**See Also**
+
+-   [log(x)](../../sql-reference/functions/math-functions.md#logx-lnx)
+
+## sign(x) {#signx}
+
+Returns the sign of a real number.
+
+**Syntax**
+
+``` sql
+sign(x)
+```
+
+**Arguments**
+
+-   `x` — Values from  `-∞` to `+∞`. Support all numeric types in ClickHouse.
+
+**Returned value**
+
+- -1 for `x < 0`
+-  0 for `x = 0`
+-  1 for `x > 0`
+
+**Examples**
+
+Sign for the zero value:
+
+``` sql
+SELECT sign(0);
+```
+
+Result:
+
+``` text
+┌─sign(0)─┐
+│       0 │
+└─────────┘
+```
+
+Sign for the positive value:
+
+``` sql
+SELECT sign(1);
+```
+
+Result:
+
+``` text
+┌─sign(1)─┐
+│       1 │
+└─────────┘
+```
+
+Sign for the negative value:
+
+``` sql
+SELECT sign(-1);
+```
+
+Result:
+
+``` text
+┌─sign(-1)─┐
+│       -1 │
+└──────────┘
+```
+
+## degrees(x) {#degreesx}
+
+Converts the input value in radians to degrees.
+
+**Syntax**
+
+``` sql
+degrees(x)
+```
+
+**Arguments**
+
+-   `x` — Input in radians. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   Value in degrees.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT degrees(3.141592653589793);
+```
+
+Result:
+
+``` text
+┌─degrees(3.141592653589793)─┐
+│                        180 │
+└────────────────────────────┘
+```
+
+## radians(x) {#radiansx}
+
+Converts the input value in degrees to radians.
+
+**Syntax**
+
+``` sql
+radians(x)
+```
+
+**Arguments**
+
+-   `x` — Input in degrees. [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Returned value**
+
+-   Value in radians.
+
+Type: [Float64](../../sql-reference/data-types/float.md#float32-float64).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT radians(180);
+```
+
+Result:
+
+``` text
+┌──────radians(180)─┐
+│ 3.141592653589793 │
+└───────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/nlp-functions.md b/docs/en/reference/sql-reference/functions/nlp-functions.md
new file mode 100644
index 00000000000..5a00252f56c
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/nlp-functions.md
@@ -0,0 +1,133 @@
+---
+sidebar_position: 67
+sidebar_label: NLP
+---
+
+# [experimental] Natural Language Processing functions {#nlp-functions}
+
+:::warning    
+This is an experimental feature that is currently in development and is not ready for general use. It will change in unpredictable backwards-incompatible ways in future releases. Set `allow_experimental_nlp_functions = 1` to enable it.
+:::
+
+## stem {#stem}
+
+Performs stemming on a given word.
+
+**Syntax**
+
+``` sql
+stem('language', word)
+```
+
+**Arguments**
+
+-   `language` — Language which rules will be applied. Must be in lowercase. [String](../../sql-reference/data-types/string.md#string).
+-   `word` — word that needs to be stemmed. Must be in lowercase. [String](../../sql-reference/data-types/string.md#string).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT arrayMap(x -> stem('en', x), ['I', 'think', 'it', 'is', 'a', 'blessing', 'in', 'disguise']) as res;
+```
+
+Result:
+
+``` text
+┌─res────────────────────────────────────────────────┐
+│ ['I','think','it','is','a','bless','in','disguis'] │
+└────────────────────────────────────────────────────┘
+```
+
+## lemmatize {#lemmatize}
+
+Performs lemmatization on a given word. Needs dictionaries to operate, which can be obtained [here](https://github.com/vpodpecan/lemmagen3/tree/master/src/lemmagen3/models).
+
+**Syntax**
+
+``` sql
+lemmatize('language', word)
+```
+
+**Arguments**
+
+-   `language` — Language which rules will be applied. [String](../../sql-reference/data-types/string.md#string).
+-   `word` — Word that needs to be lemmatized. Must be lowercase. [String](../../sql-reference/data-types/string.md#string).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT lemmatize('en', 'wolves');
+```
+
+Result:
+
+``` text
+┌─lemmatize("wolves")─┐
+│              "wolf" │
+└─────────────────────┘
+```
+
+Configuration:
+``` xml
+<lemmatizers>
+    <lemmatizer>
+        <lang>en</lang>
+        <path>en.bin</path>
+    </lemmatizer>
+</lemmatizers>
+```
+
+## synonyms {#synonyms}
+
+Finds synonyms to a given word. There are two types of synonym extensions: `plain` and `wordnet`.
+
+With the `plain` extension type we need to provide a path to a simple text file, where each line corresponds to a certain synonym set. Words in this line must be separated with space or tab characters.
+
+With the `wordnet` extension type we need to provide a path to a directory with WordNet thesaurus in it. Thesaurus must contain a WordNet sense index.
+
+**Syntax**
+
+``` sql
+synonyms('extension_name', word)
+```
+
+**Arguments**
+
+-   `extension_name` — Name of the extension in which search will be performed. [String](../../sql-reference/data-types/string.md#string).
+-   `word` — Word that will be searched in extension. [String](../../sql-reference/data-types/string.md#string).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT synonyms('list', 'important');
+```
+
+Result:
+
+``` text
+┌─synonyms('list', 'important')────────────┐
+│ ['important','big','critical','crucial'] │
+└──────────────────────────────────────────┘
+```
+
+Configuration:
+``` xml
+<synonyms_extensions>
+    <extension>
+        <name>en</name>
+        <type>plain</type>
+        <path>en.txt</path>
+    </extension>
+    <extension>
+        <name>en</name>
+        <type>wordnet</type>
+        <path>en/</path>
+    </extension>
+</synonyms_extensions>
+```
diff --git a/docs/en/reference/sql-reference/functions/other-functions.md b/docs/en/reference/sql-reference/functions/other-functions.md
new file mode 100644
index 00000000000..14cd7337d76
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/other-functions.md
@@ -0,0 +1,2505 @@
+---
+sidebar_position: 67
+sidebar_label: Other
+---
+
+# Other Functions {#other-functions}
+
+## hostName() {#hostname}
+
+Returns a string with the name of the host that this function was performed on. For distributed processing, this is the name of the remote server host, if the function is performed on a remote server.
+If it is executed in the context of a distributed table, then it generates a normal column with values relevant to each shard. Otherwise it produces a constant value.
+
+## getMacro {#getmacro}
+
+Gets a named value from the [macros](../../operations/server-configuration-parameters/settings.md#macros) section of the server configuration.
+
+**Syntax**
+
+``` sql
+getMacro(name);
+```
+
+**Arguments**
+
+-   `name` — Name to retrieve from the `macros` section. [String](../../sql-reference/data-types/string.md#string).
+
+**Returned value**
+
+-   Value of the specified macro.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+The example `macros` section in the server configuration file:
+
+``` xml
+<macros>
+    <test>Value</test>
+</macros>
+```
+
+Query:
+
+``` sql
+SELECT getMacro('test');
+```
+
+Result:
+
+``` text
+┌─getMacro('test')─┐
+│ Value            │
+└──────────────────┘
+```
+
+An alternative way to get the same value:
+
+``` sql
+SELECT * FROM system.macros
+WHERE macro = 'test';
+```
+
+``` text
+┌─macro─┬─substitution─┐
+│ test  │ Value        │
+└───────┴──────────────┘
+```
+
+## FQDN {#fqdn}
+
+Returns the fully qualified domain name.
+
+**Syntax**
+
+``` sql
+fqdn();
+```
+
+This function is case-insensitive.
+
+**Returned value**
+
+-   String with the fully qualified domain name.
+
+Type: `String`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT FQDN();
+```
+
+Result:
+
+``` text
+┌─FQDN()──────────────────────────┐
+│ clickhouse.ru-central1.internal │
+└─────────────────────────────────┘
+```
+
+## basename {#basename}
+
+Extracts the trailing part of a string after the last slash or backslash. This function if often used to extract the filename from a path.
+
+``` sql
+basename( expr )
+```
+
+**Arguments**
+
+-   `expr` — Expression resulting in a [String](../../sql-reference/data-types/string.md) type value. All the backslashes must be escaped in the resulting value.
+
+**Returned Value**
+
+A string that contains:
+
+-   The trailing part of a string after the last slash or backslash.
+
+        If the input string contains a path ending with slash or backslash, for example, `/` or `c:\`, the function returns an empty string.
+
+-   The original string if there are no slashes or backslashes.
+
+**Example**
+
+``` sql
+SELECT 'some/long/path/to/file' AS a, basename(a)
+```
+
+``` text
+┌─a──────────────────────┬─basename('some\\long\\path\\to\\file')─┐
+│ some\long\path\to\file │ file                                   │
+└────────────────────────┴────────────────────────────────────────┘
+```
+
+``` sql
+SELECT 'some\\long\\path\\to\\file' AS a, basename(a)
+```
+
+``` text
+┌─a──────────────────────┬─basename('some\\long\\path\\to\\file')─┐
+│ some\long\path\to\file │ file                                   │
+└────────────────────────┴────────────────────────────────────────┘
+```
+
+``` sql
+SELECT 'some-file-name' AS a, basename(a)
+```
+
+``` text
+┌─a──────────────┬─basename('some-file-name')─┐
+│ some-file-name │ some-file-name             │
+└────────────────┴────────────────────────────┘
+```
+
+## visibleWidth(x) {#visiblewidthx}
+
+Calculates the approximate width when outputting values to the console in text format (tab-separated).
+This function is used by the system for implementing Pretty formats.
+
+`NULL` is represented as a string corresponding to `NULL` in `Pretty` formats.
+
+``` sql
+SELECT visibleWidth(NULL)
+```
+
+``` text
+┌─visibleWidth(NULL)─┐
+│                  4 │
+└────────────────────┘
+```
+
+## toTypeName(x) {#totypenamex}
+
+Returns a string containing the type name of the passed argument.
+
+If `NULL` is passed to the function as input, then it returns the `Nullable(Nothing)` type, which corresponds to an internal `NULL` representation in ClickHouse.
+
+## blockSize() {#function-blocksize}
+
+Gets the size of the block.
+In ClickHouse, queries are always run on blocks (sets of column parts). This function allows getting the size of the block that you called it for.
+
+## byteSize {#function-bytesize}
+
+Returns estimation of uncompressed byte size of its arguments in memory.
+
+**Syntax**
+
+```sql
+byteSize(argument [, ...])
+```
+
+**Arguments**
+
+-   `argument` — Value.
+
+**Returned value**
+
+-   Estimation of byte size of the arguments in memory.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+For [String](../../sql-reference/data-types/string.md) arguments the funtion returns the string length + 9 (terminating zero + length).
+
+Query:
+
+```sql
+SELECT byteSize('string');
+```
+
+Result:
+
+```text
+┌─byteSize('string')─┐
+│                 15 │
+└────────────────────┘
+```
+
+Query:
+
+```sql
+CREATE TABLE test
+(
+    `key` Int32,
+    `u8` UInt8,
+    `u16` UInt16,
+    `u32` UInt32,
+    `u64` UInt64,
+    `i8` Int8,
+    `i16` Int16,
+    `i32` Int32,
+    `i64` Int64,
+    `f32` Float32,
+    `f64` Float64
+)
+ENGINE = MergeTree
+ORDER BY key;
+
+INSERT INTO test VALUES(1, 8, 16, 32, 64,  -8, -16, -32, -64, 32.32, 64.64);
+
+SELECT key, byteSize(u8) AS `byteSize(UInt8)`, byteSize(u16) AS `byteSize(UInt16)`, byteSize(u32) AS `byteSize(UInt32)`, byteSize(u64) AS `byteSize(UInt64)`, byteSize(i8) AS `byteSize(Int8)`, byteSize(i16) AS `byteSize(Int16)`, byteSize(i32) AS `byteSize(Int32)`, byteSize(i64) AS `byteSize(Int64)`, byteSize(f32) AS `byteSize(Float32)`, byteSize(f64) AS `byteSize(Float64)` FROM test ORDER BY key ASC FORMAT Vertical;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+key:               1
+byteSize(UInt8):   1
+byteSize(UInt16):  2
+byteSize(UInt32):  4
+byteSize(UInt64):  8
+byteSize(Int8):    1
+byteSize(Int16):   2
+byteSize(Int32):   4
+byteSize(Int64):   8
+byteSize(Float32): 4
+byteSize(Float64): 8
+```
+
+If the function takes multiple arguments, it returns their combined byte size.
+
+Query:
+
+```sql
+SELECT byteSize(NULL, 1, 0.3, '');
+```
+
+Result:
+
+```text
+┌─byteSize(NULL, 1, 0.3, '')─┐
+│                         19 │
+└────────────────────────────┘
+```
+
+## materialize(x) {#materializex}
+
+Turns a constant into a full column containing just one value.
+In ClickHouse, full columns and constants are represented differently in memory. Functions work differently for constant arguments and normal arguments (different code is executed), although the result is almost always the same. This function is for debugging this behavior.
+
+## ignore(…) {#ignore}
+
+Accepts any arguments, including `NULL`. Always returns 0.
+However, the argument is still evaluated. This can be used for benchmarks.
+
+## sleep(seconds) {#sleepseconds}
+
+Sleeps ‘seconds’ seconds on each data block. You can specify an integer or a floating-point number.
+
+## sleepEachRow(seconds) {#sleepeachrowseconds}
+
+Sleeps ‘seconds’ seconds on each row. You can specify an integer or a floating-point number.
+
+## currentDatabase() {#currentdatabase}
+
+Returns the name of the current database.
+You can use this function in table engine parameters in a CREATE TABLE query where you need to specify the database.
+
+## currentUser() {#other-function-currentuser}
+
+Returns the login of current user. Login of user, that initiated query, will be returned in case distibuted query.
+
+``` sql
+SELECT currentUser();
+```
+
+Alias: `user()`, `USER()`.
+
+**Returned values**
+
+-   Login of current user.
+-   Login of user that initiated query in case of disributed query.
+
+Type: `String`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT currentUser();
+```
+
+Result:
+
+``` text
+┌─currentUser()─┐
+│ default       │
+└───────────────┘
+```
+
+## isConstant {#is-constant}
+
+Checks whether the argument is a constant expression.
+
+A constant expression means an expression whose resulting value is known at the query analysis (i.e. before execution). For example, expressions over [literals](../../sql-reference/syntax.md#literals) are constant expressions.
+
+The function is intended for development, debugging and demonstration.
+
+**Syntax**
+
+``` sql
+isConstant(x)
+```
+
+**Arguments**
+
+-   `x` — Expression to check.
+
+**Returned values**
+
+-   `1` — `x` is constant.
+-   `0` — `x` is non-constant.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT isConstant(x + 1) FROM (SELECT 43 AS x)
+```
+
+Result:
+
+``` text
+┌─isConstant(plus(x, 1))─┐
+│                      1 │
+└────────────────────────┘
+```
+
+Query:
+
+``` sql
+WITH 3.14 AS pi SELECT isConstant(cos(pi))
+```
+
+Result:
+
+``` text
+┌─isConstant(cos(pi))─┐
+│                   1 │
+└─────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT isConstant(number) FROM numbers(1)
+```
+
+Result:
+
+``` text
+┌─isConstant(number)─┐
+│                  0 │
+└────────────────────┘
+```
+
+## isFinite(x) {#isfinitex}
+
+Accepts Float32 and Float64 and returns UInt8 equal to 1 if the argument is not infinite and not a NaN, otherwise 0.
+
+## isInfinite(x) {#isinfinitex}
+
+Accepts Float32 and Float64 and returns UInt8 equal to 1 if the argument is infinite, otherwise 0. Note that 0 is returned for a NaN.
+
+## ifNotFinite {#ifnotfinite}
+
+Checks whether floating point value is finite.
+
+**Syntax**
+
+    ifNotFinite(x,y)
+
+**Arguments**
+
+-   `x` — Value to be checked for infinity. Type: [Float\*](../../sql-reference/data-types/float.md).
+-   `y` — Fallback value. Type: [Float\*](../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   `x` if `x` is finite.
+-   `y` if `x` is not finite.
+
+**Example**
+
+Query:
+
+    SELECT 1/0 as infimum, ifNotFinite(infimum,42)
+
+Result:
+
+    ┌─infimum─┬─ifNotFinite(divide(1, 0), 42)─┐
+    │     inf │                            42 │
+    └─────────┴───────────────────────────────┘
+
+You can get similar result by using [ternary operator](../../sql-reference/functions/conditional-functions.md#ternary-operator): `isFinite(x) ? x : y`.
+
+## isNaN(x) {#isnanx}
+
+Accepts Float32 and Float64 and returns UInt8 equal to 1 if the argument is a NaN, otherwise 0.
+
+## hasColumnInTable(\[‘hostname’\[, ‘username’\[, ‘password’\]\],\] ‘database’, ‘table’, ‘column’) {#hascolumnintablehostname-username-password-database-table-column}
+
+Accepts constant strings: database name, table name, and column name. Returns a UInt8 constant expression equal to 1 if there is a column, otherwise 0. If the hostname parameter is set, the test will run on a remote server.
+The function throws an exception if the table does not exist.
+For elements in a nested data structure, the function checks for the existence of a column. For the nested data structure itself, the function returns 0.
+
+## bar {#function-bar}
+
+Allows building a unicode-art diagram.
+
+`bar(x, min, max, width)` draws a band with a width proportional to `(x - min)` and equal to `width` characters when `x = max`.
+
+**Arguments**
+
+-   `x` — Size to display.
+-   `min, max` — Integer constants. The value must fit in `Int64`.
+-   `width` — Constant, positive integer, can be fractional.
+
+The band is drawn with accuracy to one eighth of a symbol.
+
+Example:
+
+``` sql
+SELECT
+    toHour(EventTime) AS h,
+    count() AS c,
+    bar(c, 0, 600000, 20) AS bar
+FROM test.hits
+GROUP BY h
+ORDER BY h ASC
+```
+
+``` text
+┌──h─┬──────c─┬─bar────────────────┐
+│  0 │ 292907 │ █████████▋         │
+│  1 │ 180563 │ ██████             │
+│  2 │ 114861 │ ███▋               │
+│  3 │  85069 │ ██▋                │
+│  4 │  68543 │ ██▎                │
+│  5 │  78116 │ ██▌                │
+│  6 │ 113474 │ ███▋               │
+│  7 │ 170678 │ █████▋             │
+│  8 │ 278380 │ █████████▎         │
+│  9 │ 391053 │ █████████████      │
+│ 10 │ 457681 │ ███████████████▎   │
+│ 11 │ 493667 │ ████████████████▍  │
+│ 12 │ 509641 │ ████████████████▊  │
+│ 13 │ 522947 │ █████████████████▍ │
+│ 14 │ 539954 │ █████████████████▊ │
+│ 15 │ 528460 │ █████████████████▌ │
+│ 16 │ 539201 │ █████████████████▊ │
+│ 17 │ 523539 │ █████████████████▍ │
+│ 18 │ 506467 │ ████████████████▊  │
+│ 19 │ 520915 │ █████████████████▎ │
+│ 20 │ 521665 │ █████████████████▍ │
+│ 21 │ 542078 │ ██████████████████ │
+│ 22 │ 493642 │ ████████████████▍  │
+│ 23 │ 400397 │ █████████████▎     │
+└────┴────────┴────────────────────┘
+```
+
+## transform {#transform}
+
+Transforms a value according to the explicitly defined mapping of some elements to other ones.
+There are two variations of this function:
+
+### transform(x, array_from, array_to, default) {#transformx-array-from-array-to-default}
+
+`x` – What to transform.
+
+`array_from` – Constant array of values for converting.
+
+`array_to` – Constant array of values to convert the values in ‘from’ to.
+
+`default` – Which value to use if ‘x’ is not equal to any of the values in ‘from’.
+
+`array_from` and `array_to` – Arrays of the same size.
+
+Types:
+
+`transform(T, Array(T), Array(U), U) -> U`
+
+`T` and `U` can be numeric, string, or Date or DateTime types.
+Where the same letter is indicated (T or U), for numeric types these might not be matching types, but types that have a common type.
+For example, the first argument can have the Int64 type, while the second has the Array(UInt16) type.
+
+If the ‘x’ value is equal to one of the elements in the ‘array_from’ array, it returns the existing element (that is numbered the same) from the ‘array_to’ array. Otherwise, it returns ‘default’. If there are multiple matching elements in ‘array_from’, it returns one of the matches.
+
+Example:
+
+``` sql
+SELECT
+    transform(SearchEngineID, [2, 3], ['Yandex', 'Google'], 'Other') AS title,
+    count() AS c
+FROM test.hits
+WHERE SearchEngineID != 0
+GROUP BY title
+ORDER BY c DESC
+```
+
+``` text
+┌─title─────┬──────c─┐
+│ Yandex    │ 498635 │
+│ Google    │ 229872 │
+│ Other     │ 104472 │
+└───────────┴────────┘
+```
+
+### transform(x, array_from, array_to) {#transformx-array-from-array-to}
+
+Differs from the first variation in that the ‘default’ argument is omitted.
+If the ‘x’ value is equal to one of the elements in the ‘array_from’ array, it returns the matching element (that is numbered the same) from the ‘array_to’ array. Otherwise, it returns ‘x’.
+
+Types:
+
+`transform(T, Array(T), Array(T)) -> T`
+
+Example:
+
+``` sql
+SELECT
+    transform(domain(Referer), ['yandex.ru', 'google.ru', 'vk.com'], ['www.yandex', 'example.com']) AS s,
+    count() AS c
+FROM test.hits
+GROUP BY domain(Referer)
+ORDER BY count() DESC
+LIMIT 10
+```
+
+``` text
+┌─s──────────────┬───────c─┐
+│                │ 2906259 │
+│ www.yandex     │  867767 │
+│ ███████.ru     │  313599 │
+│ mail.yandex.ru │  107147 │
+│ ██████.ru      │  100355 │
+│ █████████.ru   │   65040 │
+│ news.yandex.ru │   64515 │
+│ ██████.net     │   59141 │
+│ example.com    │   57316 │
+└────────────────┴─────────┘
+```
+
+## formatReadableSize(x) {#formatreadablesizex}
+
+Accepts the size (number of bytes). Returns a rounded size with a suffix (KiB, MiB, etc.) as a string.
+
+Example:
+
+``` sql
+SELECT
+    arrayJoin([1, 1024, 1024*1024, 192851925]) AS filesize_bytes,
+    formatReadableSize(filesize_bytes) AS filesize
+```
+
+``` text
+┌─filesize_bytes─┬─filesize───┐
+│              1 │ 1.00 B     │
+│           1024 │ 1.00 KiB   │
+│        1048576 │ 1.00 MiB   │
+│      192851925 │ 183.92 MiB │
+└────────────────┴────────────┘
+```
+
+## formatReadableQuantity(x) {#formatreadablequantityx}
+
+Accepts the number. Returns a rounded number with a suffix (thousand, million, billion, etc.) as a string.
+
+It is useful for reading big numbers by human.
+
+Example:
+
+``` sql
+SELECT
+    arrayJoin([1024, 1234 * 1000, (4567 * 1000) * 1000, 98765432101234]) AS number,
+    formatReadableQuantity(number) AS number_for_humans
+```
+
+``` text
+┌─────────number─┬─number_for_humans─┐
+│           1024 │ 1.02 thousand     │
+│        1234000 │ 1.23 million      │
+│     4567000000 │ 4.57 billion      │
+│ 98765432101234 │ 98.77 trillion    │
+└────────────────┴───────────────────┘
+```
+
+## formatReadableTimeDelta {#formatreadabletimedelta}
+
+Accepts the time delta in seconds. Returns a time delta with (year, month, day, hour, minute, second) as a string.
+
+**Syntax**
+
+``` sql
+formatReadableTimeDelta(column[, maximum_unit])
+```
+
+**Arguments**
+
+-   `column` — A column with numeric time delta.
+-   `maximum_unit` — Optional. Maximum unit to show. Acceptable values seconds, minutes, hours, days, months, years.
+
+Example:
+
+``` sql
+SELECT
+    arrayJoin([100, 12345, 432546534]) AS elapsed,
+    formatReadableTimeDelta(elapsed) AS time_delta
+```
+
+``` text
+┌────elapsed─┬─time_delta ─────────────────────────────────────────────────────┐
+│        100 │ 1 minute and 40 seconds                                         │
+│      12345 │ 3 hours, 25 minutes and 45 seconds                              │
+│  432546534 │ 13 years, 8 months, 17 days, 7 hours, 48 minutes and 54 seconds │
+└────────────┴─────────────────────────────────────────────────────────────────┘
+```
+
+``` sql
+SELECT
+    arrayJoin([100, 12345, 432546534]) AS elapsed,
+    formatReadableTimeDelta(elapsed, 'minutes') AS time_delta
+```
+
+``` text
+┌────elapsed─┬─time_delta ─────────────────────────────────────────────────────┐
+│        100 │ 1 minute and 40 seconds                                         │
+│      12345 │ 205 minutes and 45 seconds                                      │
+│  432546534 │ 7209108 minutes and 54 seconds                                  │
+└────────────┴─────────────────────────────────────────────────────────────────┘
+```
+
+## least(a, b) {#leasta-b}
+
+Returns the smallest value from a and b.
+
+## greatest(a, b) {#greatesta-b}
+
+Returns the largest value of a and b.
+
+## uptime() {#uptime}
+
+Returns the server’s uptime in seconds.
+If it is executed in the context of a distributed table, then it generates a normal column with values relevant to each shard. Otherwise it produces a constant value.
+
+## version() {#version}
+
+Returns the version of the server as a string.
+If it is executed in the context of a distributed table, then it generates a normal column with values relevant to each shard. Otherwise it produces a constant value.
+
+## buildId() {#buildid}
+
+Returns the build ID generated by a compiler for the running ClickHouse server binary.
+If it is executed in the context of a distributed table, then it generates a normal column with values relevant to each shard. Otherwise it produces a constant value.
+
+
+## blockNumber {#blocknumber}
+
+Returns the sequence number of the data block where the row is located.
+
+## rowNumberInBlock {#function-rownumberinblock}
+
+Returns the ordinal number of the row in the data block. Different data blocks are always recalculated.
+
+## rowNumberInAllBlocks() {#rownumberinallblocks}
+
+Returns the ordinal number of the row in the data block. This function only considers the affected data blocks.
+
+## neighbor {#neighbor}
+
+The window function that provides access to a row at a specified offset which comes before or after the current row of a given column.
+
+**Syntax**
+
+``` sql
+neighbor(column, offset[, default_value])
+```
+
+The result of the function depends on the affected data blocks and the order of data in the block.
+
+:::warning    
+It can reach the neighbor rows only inside the currently processed data block.
+:::
+
+The rows order used during the calculation of `neighbor` can differ from the order of rows returned to the user.
+To prevent that you can make a subquery with [ORDER BY](../../sql-reference/statements/select/order-by.md) and call the function from outside the subquery.
+
+**Arguments**
+
+-   `column` — A column name or scalar expression.
+-   `offset` — The number of rows forwards or backwards from the current row of `column`. [Int64](../../sql-reference/data-types/int-uint.md).
+-   `default_value` — Optional. The value to be returned if offset goes beyond the scope of the block. Type of data blocks affected.
+
+**Returned values**
+
+-   Value for `column` in `offset` distance from current row if `offset` value is not outside block bounds.
+-   Default value for `column` if `offset` value is outside block bounds. If `default_value` is given, then it will be used.
+
+Type: type of data blocks affected or default value type.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT number, neighbor(number, 2) FROM system.numbers LIMIT 10;
+```
+
+Result:
+
+``` text
+┌─number─┬─neighbor(number, 2)─┐
+│      0 │                   2 │
+│      1 │                   3 │
+│      2 │                   4 │
+│      3 │                   5 │
+│      4 │                   6 │
+│      5 │                   7 │
+│      6 │                   8 │
+│      7 │                   9 │
+│      8 │                   0 │
+│      9 │                   0 │
+└────────┴─────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT number, neighbor(number, 2, 999) FROM system.numbers LIMIT 10;
+```
+
+Result:
+
+``` text
+┌─number─┬─neighbor(number, 2, 999)─┐
+│      0 │                        2 │
+│      1 │                        3 │
+│      2 │                        4 │
+│      3 │                        5 │
+│      4 │                        6 │
+│      5 │                        7 │
+│      6 │                        8 │
+│      7 │                        9 │
+│      8 │                      999 │
+│      9 │                      999 │
+└────────┴──────────────────────────┘
+```
+
+This function can be used to compute year-over-year metric value:
+
+Query:
+
+``` sql
+WITH toDate('2018-01-01') AS start_date
+SELECT
+    toStartOfMonth(start_date + (number * 32)) AS month,
+    toInt32(month) % 100 AS money,
+    neighbor(money, -12) AS prev_year,
+    round(prev_year / money, 2) AS year_over_year
+FROM numbers(16)
+```
+
+Result:
+
+``` text
+┌──────month─┬─money─┬─prev_year─┬─year_over_year─┐
+│ 2018-01-01 │    32 │         0 │              0 │
+│ 2018-02-01 │    63 │         0 │              0 │
+│ 2018-03-01 │    91 │         0 │              0 │
+│ 2018-04-01 │    22 │         0 │              0 │
+│ 2018-05-01 │    52 │         0 │              0 │
+│ 2018-06-01 │    83 │         0 │              0 │
+│ 2018-07-01 │    13 │         0 │              0 │
+│ 2018-08-01 │    44 │         0 │              0 │
+│ 2018-09-01 │    75 │         0 │              0 │
+│ 2018-10-01 │     5 │         0 │              0 │
+│ 2018-11-01 │    36 │         0 │              0 │
+│ 2018-12-01 │    66 │         0 │              0 │
+│ 2019-01-01 │    97 │        32 │           0.33 │
+│ 2019-02-01 │    28 │        63 │           2.25 │
+│ 2019-03-01 │    56 │        91 │           1.62 │
+│ 2019-04-01 │    87 │        22 │           0.25 │
+└────────────┴───────┴───────────┴────────────────┘
+```
+
+## runningDifference(x) {#other_functions-runningdifference}
+
+Calculates the difference between successive row values ​​in the data block.
+Returns 0 for the first row and the difference from the previous row for each subsequent row.
+
+:::warning    
+It can reach the previous row only inside the currently processed data block.
+:::
+
+The result of the function depends on the affected data blocks and the order of data in the block.
+
+The rows order used during the calculation of `runningDifference` can differ from the order of rows returned to the user.
+To prevent that you can make a subquery with [ORDER BY](../../sql-reference/statements/select/order-by.md) and call the function from outside the subquery.
+
+Example:
+
+``` sql
+SELECT
+    EventID,
+    EventTime,
+    runningDifference(EventTime) AS delta
+FROM
+(
+    SELECT
+        EventID,
+        EventTime
+    FROM events
+    WHERE EventDate = '2016-11-24'
+    ORDER BY EventTime ASC
+    LIMIT 5
+)
+```
+
+``` text
+┌─EventID─┬───────────EventTime─┬─delta─┐
+│    1106 │ 2016-11-24 00:00:04 │     0 │
+│    1107 │ 2016-11-24 00:00:05 │     1 │
+│    1108 │ 2016-11-24 00:00:05 │     0 │
+│    1109 │ 2016-11-24 00:00:09 │     4 │
+│    1110 │ 2016-11-24 00:00:10 │     1 │
+└─────────┴─────────────────────┴───────┘
+```
+
+Please note - block size affects the result. With each new block, the `runningDifference` state is reset.
+
+``` sql
+SELECT
+    number,
+    runningDifference(number + 1) AS diff
+FROM numbers(100000)
+WHERE diff != 1
+```
+
+``` text
+┌─number─┬─diff─┐
+│      0 │    0 │
+└────────┴──────┘
+┌─number─┬─diff─┐
+│  65536 │    0 │
+└────────┴──────┘
+```
+
+``` sql
+set max_block_size=100000 -- default value is 65536!
+
+SELECT
+    number,
+    runningDifference(number + 1) AS diff
+FROM numbers(100000)
+WHERE diff != 1
+```
+
+``` text
+┌─number─┬─diff─┐
+│      0 │    0 │
+└────────┴──────┘
+```
+
+## runningDifferenceStartingWithFirstValue {#runningdifferencestartingwithfirstvalue}
+
+Same as for [runningDifference](./other-functions.md#other_functions-runningdifference), the difference is the value of the first row, returned the value of the first row, and each subsequent row returns the difference from the previous row.
+
+## runningConcurrency {#runningconcurrency}
+
+Calculates the number of concurrent events.
+Each event has a start time and an end time. The start time is included in the event, while the end time is excluded. Columns with a start time and an end time must be of the same data type.
+The function calculates the total number of active (concurrent) events for each event start time.
+
+
+:::warning    
+Events must be ordered by the start time in ascending order. If this requirement is violated the function raises an exception. Every data block is processed separately. If events from different data blocks overlap then they can not be processed correctly.
+:::
+
+**Syntax**
+
+``` sql
+runningConcurrency(start, end)
+```
+
+**Arguments**
+
+-   `start` — A column with the start time of events. [Date](../../sql-reference/data-types/date.md), [DateTime](../../sql-reference/data-types/datetime.md), or [DateTime64](../../sql-reference/data-types/datetime64.md).
+-   `end` — A column with the end time of events.  [Date](../../sql-reference/data-types/date.md), [DateTime](../../sql-reference/data-types/datetime.md), or [DateTime64](../../sql-reference/data-types/datetime64.md).
+
+**Returned values**
+
+-   The number of concurrent events at each event start time.
+
+Type: [UInt32](../../sql-reference/data-types/int-uint.md)
+
+**Example**
+
+Consider the table:
+
+``` text
+┌──────start─┬────────end─┐
+│ 2021-03-03 │ 2021-03-11 │
+│ 2021-03-06 │ 2021-03-12 │
+│ 2021-03-07 │ 2021-03-08 │
+│ 2021-03-11 │ 2021-03-12 │
+└────────────┴────────────┘
+```
+
+Query:
+
+``` sql
+SELECT start, runningConcurrency(start, end) FROM example_table;
+```
+
+Result:
+
+``` text
+┌──────start─┬─runningConcurrency(start, end)─┐
+│ 2021-03-03 │                              1 │
+│ 2021-03-06 │                              2 │
+│ 2021-03-07 │                              3 │
+│ 2021-03-11 │                              2 │
+└────────────┴────────────────────────────────┘
+```
+
+## MACNumToString(num) {#macnumtostringnum}
+
+Accepts a UInt64 number. Interprets it as a MAC address in big endian. Returns a string containing the corresponding MAC address in the format AA:BB:CC:DD:EE:FF (colon-separated numbers in hexadecimal form).
+
+## MACStringToNum(s) {#macstringtonums}
+
+The inverse function of MACNumToString. If the MAC address has an invalid format, it returns 0.
+
+## MACStringToOUI(s) {#macstringtoouis}
+
+Accepts a MAC address in the format AA:BB:CC:DD:EE:FF (colon-separated numbers in hexadecimal form). Returns the first three octets as a UInt64 number. If the MAC address has an invalid format, it returns 0.
+
+## getSizeOfEnumType {#getsizeofenumtype}
+
+Returns the number of fields in [Enum](../../sql-reference/data-types/enum.md).
+
+``` sql
+getSizeOfEnumType(value)
+```
+
+**Arguments:**
+
+-   `value` — Value of type `Enum`.
+
+**Returned values**
+
+-   The number of fields with `Enum` input values.
+-   An exception is thrown if the type is not `Enum`.
+
+**Example**
+
+``` sql
+SELECT getSizeOfEnumType( CAST('a' AS Enum8('a' = 1, 'b' = 2) ) ) AS x
+```
+
+``` text
+┌─x─┐
+│ 2 │
+└───┘
+```
+
+## blockSerializedSize {#blockserializedsize}
+
+Returns size on disk (without taking into account compression).
+
+``` sql
+blockSerializedSize(value[, value[, ...]])
+```
+
+**Arguments**
+
+-   `value` — Any value.
+
+**Returned values**
+
+-   The number of bytes that will be written to disk for block of values (without compression).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT blockSerializedSize(maxState(1)) as x
+```
+
+Result:
+
+``` text
+┌─x─┐
+│ 2 │
+└───┘
+```
+
+## toColumnTypeName {#tocolumntypename}
+
+Returns the name of the class that represents the data type of the column in RAM.
+
+``` sql
+toColumnTypeName(value)
+```
+
+**Arguments:**
+
+-   `value` — Any type of value.
+
+**Returned values**
+
+-   A string with the name of the class that is used for representing the `value` data type in RAM.
+
+**Example of the difference between`toTypeName ' and ' toColumnTypeName`**
+
+``` sql
+SELECT toTypeName(CAST('2018-01-01 01:02:03' AS DateTime))
+```
+
+``` text
+┌─toTypeName(CAST('2018-01-01 01:02:03', 'DateTime'))─┐
+│ DateTime                                            │
+└─────────────────────────────────────────────────────┘
+```
+
+``` sql
+SELECT toColumnTypeName(CAST('2018-01-01 01:02:03' AS DateTime))
+```
+
+``` text
+┌─toColumnTypeName(CAST('2018-01-01 01:02:03', 'DateTime'))─┐
+│ Const(UInt32)                                             │
+└───────────────────────────────────────────────────────────┘
+```
+
+The example shows that the `DateTime` data type is stored in memory as `Const(UInt32)`.
+
+## dumpColumnStructure {#dumpcolumnstructure}
+
+Outputs a detailed description of data structures in RAM
+
+``` sql
+dumpColumnStructure(value)
+```
+
+**Arguments:**
+
+-   `value` — Any type of value.
+
+**Returned values**
+
+-   A string describing the structure that is used for representing the `value` data type in RAM.
+
+**Example**
+
+``` sql
+SELECT dumpColumnStructure(CAST('2018-01-01 01:02:03', 'DateTime'))
+```
+
+``` text
+┌─dumpColumnStructure(CAST('2018-01-01 01:02:03', 'DateTime'))─┐
+│ DateTime, Const(size = 1, UInt32(size = 1))                  │
+└──────────────────────────────────────────────────────────────┘
+```
+
+## defaultValueOfArgumentType {#defaultvalueofargumenttype}
+
+Outputs the default value for the data type.
+
+Does not include default values for custom columns set by the user.
+
+``` sql
+defaultValueOfArgumentType(expression)
+```
+
+**Arguments:**
+
+-   `expression` — Arbitrary type of value or an expression that results in a value of an arbitrary type.
+
+**Returned values**
+
+-   `0` for numbers.
+-   Empty string for strings.
+-   `ᴺᵁᴸᴸ` for [Nullable](../../sql-reference/data-types/nullable.md).
+
+**Example**
+
+``` sql
+SELECT defaultValueOfArgumentType( CAST(1 AS Int8) )
+```
+
+``` text
+┌─defaultValueOfArgumentType(CAST(1, 'Int8'))─┐
+│                                           0 │
+└─────────────────────────────────────────────┘
+```
+
+``` sql
+SELECT defaultValueOfArgumentType( CAST(1 AS Nullable(Int8) ) )
+```
+
+``` text
+┌─defaultValueOfArgumentType(CAST(1, 'Nullable(Int8)'))─┐
+│                                                  ᴺᵁᴸᴸ │
+└───────────────────────────────────────────────────────┘
+```
+
+## defaultValueOfTypeName {#defaultvalueoftypename}
+
+Outputs the default value for given type name.
+
+Does not include default values for custom columns set by the user.
+
+``` sql
+defaultValueOfTypeName(type)
+```
+
+**Arguments:**
+
+-   `type` — A string representing a type name.
+
+**Returned values**
+
+-   `0` for numbers.
+-   Empty string for strings.
+-   `ᴺᵁᴸᴸ` for [Nullable](../../sql-reference/data-types/nullable.md).
+
+**Example**
+
+``` sql
+SELECT defaultValueOfTypeName('Int8')
+```
+
+``` text
+┌─defaultValueOfTypeName('Int8')─┐
+│                              0 │
+└────────────────────────────────┘
+```
+
+``` sql
+SELECT defaultValueOfTypeName('Nullable(Int8)')
+```
+
+``` text
+┌─defaultValueOfTypeName('Nullable(Int8)')─┐
+│                                     ᴺᵁᴸᴸ │
+└──────────────────────────────────────────┘
+```
+
+## indexHint {#indexhint}
+The function is intended for debugging and introspection purposes. The function ignores it's argument and always returns 1. Arguments are not even evaluated.
+
+But for the purpose of index analysis, the argument of this function is analyzed as if it was present directly without being wrapped inside `indexHint` function. This allows to select data in index ranges by the corresponding condition but without further filtering by this condition. The index in ClickHouse is sparse and using `indexHint` will yield more data than specifying the same condition directly.
+
+**Syntax**
+
+```sql
+SELECT * FROM table WHERE indexHint(<expression>)
+```
+
+**Returned value**
+
+1. Type: [Uint8](https://clickhouse.com/docs/en/data_types/int_uint/#diapazony-uint).
+
+**Example**
+
+Here is the example of test data from the table [ontime](../../example-datasets/ontime.md).
+
+Input table:
+
+```sql
+SELECT count() FROM ontime
+```
+
+```text
+┌─count()─┐
+│ 4276457 │
+└─────────┘
+```
+
+The table has indexes on the fields `(FlightDate, (Year, FlightDate))`.
+
+Create a query, where the index is not used.
+
+Query:
+
+```sql
+SELECT FlightDate AS k, count() FROM ontime GROUP BY k ORDER BY k
+```
+
+ClickHouse processed the entire table (`Processed 4.28 million rows`).
+
+Result:
+
+```text
+┌──────────k─┬─count()─┐
+│ 2017-01-01 │   13970 │
+│ 2017-01-02 │   15882 │
+........................
+│ 2017-09-28 │   16411 │
+│ 2017-09-29 │   16384 │
+│ 2017-09-30 │   12520 │
+└────────────┴─────────┘
+```
+
+To apply the index, select a specific date.
+
+Query:
+
+```sql
+SELECT FlightDate AS k, count() FROM ontime WHERE k = '2017-09-15' GROUP BY k ORDER BY k
+```
+
+By using the index, ClickHouse processed a significantly smaller number of rows (`Processed 32.74 thousand rows`).
+
+Result:
+
+```text
+┌──────────k─┬─count()─┐
+│ 2017-09-15 │   16428 │
+└────────────┴─────────┘
+```
+
+Now wrap the expression `k = '2017-09-15'` into `indexHint` function.
+
+Query:
+
+```sql
+SELECT
+    FlightDate AS k,
+    count()
+FROM ontime
+WHERE indexHint(k = '2017-09-15')
+GROUP BY k
+ORDER BY k ASC
+```
+
+ClickHouse used the index in the same way as the previous time (`Processed 32.74 thousand rows`).
+The expression `k = '2017-09-15'` was not used when generating the result.
+In examle the `indexHint` function allows to see adjacent dates.
+
+Result:
+
+```text
+┌──────────k─┬─count()─┐
+│ 2017-09-14 │    7071 │
+│ 2017-09-15 │   16428 │
+│ 2017-09-16 │    1077 │
+│ 2017-09-30 │    8167 │
+└────────────┴─────────┘
+```
+
+## replicate {#other-functions-replicate}
+
+Creates an array with a single value.
+
+Used for internal implementation of [arrayJoin](../../sql-reference/functions/array-join.md#functions_arrayjoin).
+
+``` sql
+SELECT replicate(x, arr);
+```
+
+**Arguments:**
+
+-   `arr` — Original array. ClickHouse creates a new array of the same length as the original and fills it with the value `x`.
+-   `x` — The value that the resulting array will be filled with.
+
+**Returned value**
+
+An array filled with the value `x`.
+
+Type: `Array`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT replicate(1, ['a', 'b', 'c'])
+```
+
+Result:
+
+``` text
+┌─replicate(1, ['a', 'b', 'c'])─┐
+│ [1,1,1]                       │
+└───────────────────────────────┘
+```
+
+## filesystemAvailable {#filesystemavailable}
+
+Returns amount of remaining space on the filesystem where the files of the databases located. It is always smaller than total free space ([filesystemFree](#filesystemfree)) because some space is reserved for OS.
+
+**Syntax**
+
+``` sql
+filesystemAvailable()
+```
+
+**Returned value**
+
+-   The amount of remaining space available in bytes.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT formatReadableSize(filesystemAvailable()) AS "Available space", toTypeName(filesystemAvailable()) AS "Type";
+```
+
+Result:
+
+``` text
+┌─Available space─┬─Type───┐
+│ 30.75 GiB       │ UInt64 │
+└─────────────────┴────────┘
+```
+
+## filesystemFree {#filesystemfree}
+
+Returns total amount of the free space on the filesystem where the files of the databases located. See also `filesystemAvailable`
+
+**Syntax**
+
+``` sql
+filesystemFree()
+```
+
+**Returned value**
+
+-   Amount of free space in bytes.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT formatReadableSize(filesystemFree()) AS "Free space", toTypeName(filesystemFree()) AS "Type";
+```
+
+Result:
+
+``` text
+┌─Free space─┬─Type───┐
+│ 32.39 GiB  │ UInt64 │
+└────────────┴────────┘
+```
+
+## filesystemCapacity {#filesystemcapacity}
+
+Returns the capacity of the filesystem in bytes. For evaluation, the [path](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-path) to the data directory must be configured.
+
+**Syntax**
+
+``` sql
+filesystemCapacity()
+```
+
+**Returned value**
+
+-   Capacity information of the filesystem in bytes.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT formatReadableSize(filesystemCapacity()) AS "Capacity", toTypeName(filesystemCapacity()) AS "Type"
+```
+
+Result:
+
+``` text
+┌─Capacity──┬─Type───┐
+│ 39.32 GiB │ UInt64 │
+└───────────┴────────┘
+```
+
+## initializeAggregation {#initializeaggregation}
+
+Calculates result of aggregate function based on single value. It is intended to use this function to initialize aggregate functions with combinator [-State](../../sql-reference/aggregate-functions/combinators.md#agg-functions-combinator-state). You can create states of aggregate functions and insert them to columns of type [AggregateFunction](../../sql-reference/data-types/aggregatefunction.md#data-type-aggregatefunction) or use initialized aggregates as default values.
+
+**Syntax**
+
+``` sql
+initializeAggregation (aggregate_function, arg1, arg2, ..., argN)
+```
+
+**Arguments**
+
+-   `aggregate_function` — Name of the aggregation function to initialize. [String](../../sql-reference/data-types/string.md).
+-   `arg` — Arguments of aggregate function.
+
+**Returned value(s)**
+
+- Result of aggregation for every row passed to the function.
+
+The return type is the same as the return type of function, that `initializeAgregation` takes as first argument.
+
+**Example**
+
+Query:
+
+```sql
+SELECT uniqMerge(state) FROM (SELECT initializeAggregation('uniqState', number % 3) AS state FROM numbers(10000));
+```
+Result:
+
+```text
+┌─uniqMerge(state)─┐
+│                3 │
+└──────────────────┘
+```
+
+Query:
+
+```sql
+SELECT finalizeAggregation(state), toTypeName(state) FROM (SELECT initializeAggregation('sumState', number % 3) AS state FROM numbers(5));
+```
+Result:
+
+```text
+┌─finalizeAggregation(state)─┬─toTypeName(state)─────────────┐
+│                          0 │ AggregateFunction(sum, UInt8) │
+│                          1 │ AggregateFunction(sum, UInt8) │
+│                          2 │ AggregateFunction(sum, UInt8) │
+│                          0 │ AggregateFunction(sum, UInt8) │
+│                          1 │ AggregateFunction(sum, UInt8) │
+└────────────────────────────┴───────────────────────────────┘
+```
+
+Example with `AggregatingMergeTree` table engine and `AggregateFunction` column:
+
+```sql
+CREATE TABLE metrics
+(
+    key UInt64,
+    value AggregateFunction(sum, UInt64) DEFAULT initializeAggregation('sumState', toUInt64(0))
+)
+ENGINE = AggregatingMergeTree
+ORDER BY key
+```
+
+```sql
+INSERT INTO metrics VALUES (0, initializeAggregation('sumState', toUInt64(42)))
+```
+
+**See Also**
+-   [arrayReduce](../../sql-reference/functions/array-functions.md#arrayreduce)
+
+## finalizeAggregation {#function-finalizeaggregation}
+
+Takes state of aggregate function. Returns result of aggregation (or finalized state when using[-State](../../sql-reference/aggregate-functions/combinators.md#agg-functions-combinator-state) combinator).
+
+**Syntax**
+
+``` sql
+finalizeAggregation(state)
+```
+
+**Arguments**
+
+-   `state` — State of aggregation. [AggregateFunction](../../sql-reference/data-types/aggregatefunction.md#data-type-aggregatefunction).
+
+**Returned value(s)**
+
+-   Value/values that was aggregated.
+
+Type: Value of any types that was aggregated.
+
+**Examples**
+
+Query:
+
+```sql
+SELECT finalizeAggregation(( SELECT countState(number) FROM numbers(10)));
+```
+
+Result:
+
+```text
+┌─finalizeAggregation(_subquery16)─┐
+│                               10 │
+└──────────────────────────────────┘
+```
+
+Query:
+
+```sql
+SELECT finalizeAggregation(( SELECT sumState(number) FROM numbers(10)));
+```
+
+Result:
+
+```text
+┌─finalizeAggregation(_subquery20)─┐
+│                               45 │
+└──────────────────────────────────┘
+```
+
+Note that `NULL` values are ignored.
+
+Query:
+
+```sql
+SELECT finalizeAggregation(arrayReduce('anyState', [NULL, 2, 3]));
+```
+
+Result:
+
+```text
+┌─finalizeAggregation(arrayReduce('anyState', [NULL, 2, 3]))─┐
+│                                                          2 │
+└────────────────────────────────────────────────────────────┘
+```
+
+Combined example:
+
+Query:
+
+```sql
+WITH initializeAggregation('sumState', number) AS one_row_sum_state
+SELECT
+    number,
+    finalizeAggregation(one_row_sum_state) AS one_row_sum,
+    runningAccumulate(one_row_sum_state) AS cumulative_sum
+FROM numbers(10);
+```
+
+Result:
+
+```text
+┌─number─┬─one_row_sum─┬─cumulative_sum─┐
+│      0 │           0 │              0 │
+│      1 │           1 │              1 │
+│      2 │           2 │              3 │
+│      3 │           3 │              6 │
+│      4 │           4 │             10 │
+│      5 │           5 │             15 │
+│      6 │           6 │             21 │
+│      7 │           7 │             28 │
+│      8 │           8 │             36 │
+│      9 │           9 │             45 │
+└────────┴─────────────┴────────────────┘
+```
+
+**See Also**
+-   [arrayReduce](../../sql-reference/functions/array-functions.md#arrayreduce)
+-   [initializeAggregation](#initializeaggregation)
+
+## runningAccumulate {#runningaccumulate}
+
+Accumulates states of an aggregate function for each row of a data block.
+
+:::warning    
+The state is reset for each new data block.
+:::
+
+**Syntax**
+
+``` sql
+runningAccumulate(agg_state[, grouping]);
+```
+
+**Arguments**
+
+-   `agg_state` — State of the aggregate function. [AggregateFunction](../../sql-reference/data-types/aggregatefunction.md#data-type-aggregatefunction).
+-   `grouping` — Grouping key. Optional. The state of the function is reset if the `grouping` value is changed. It can be any of the [supported data types](../../sql-reference/data-types/index.md) for which the equality operator is defined.
+
+**Returned value**
+
+-   Each resulting row contains a result of the aggregate function, accumulated for all the input rows from 0 to the current position. `runningAccumulate` resets states for each new data block or when the `grouping` value changes.
+
+Type depends on the aggregate function used.
+
+**Examples**
+
+Consider how you can use `runningAccumulate` to find the cumulative sum of numbers without and with grouping.
+
+Query:
+
+``` sql
+SELECT k, runningAccumulate(sum_k) AS res FROM (SELECT number as k, sumState(k) AS sum_k FROM numbers(10) GROUP BY k ORDER BY k);
+```
+
+Result:
+
+``` text
+┌─k─┬─res─┐
+│ 0 │   0 │
+│ 1 │   1 │
+│ 2 │   3 │
+│ 3 │   6 │
+│ 4 │  10 │
+│ 5 │  15 │
+│ 6 │  21 │
+│ 7 │  28 │
+│ 8 │  36 │
+│ 9 │  45 │
+└───┴─────┘
+```
+
+The subquery generates `sumState` for every number from `0` to `9`. `sumState` returns the state of the [sum](../../sql-reference/aggregate-functions/reference/sum.md) function that contains the sum of a single number.
+
+The whole query does the following:
+
+1.  For the first row, `runningAccumulate` takes `sumState(0)` and returns `0`.
+2.  For the second row, the function merges `sumState(0)` and `sumState(1)` resulting in `sumState(0 + 1)`, and returns `1` as a result.
+3.  For the third row, the function merges `sumState(0 + 1)` and `sumState(2)` resulting in `sumState(0 + 1 + 2)`, and returns `3` as a result.
+4.  The actions are repeated until the block ends.
+
+The following example shows the `groupping` parameter usage:
+
+Query:
+
+``` sql
+SELECT
+    grouping,
+    item,
+    runningAccumulate(state, grouping) AS res
+FROM
+(
+    SELECT
+        toInt8(number / 4) AS grouping,
+        number AS item,
+        sumState(number) AS state
+    FROM numbers(15)
+    GROUP BY item
+    ORDER BY item ASC
+);
+```
+
+Result:
+
+``` text
+┌─grouping─┬─item─┬─res─┐
+│        0 │    0 │   0 │
+│        0 │    1 │   1 │
+│        0 │    2 │   3 │
+│        0 │    3 │   6 │
+│        1 │    4 │   4 │
+│        1 │    5 │   9 │
+│        1 │    6 │  15 │
+│        1 │    7 │  22 │
+│        2 │    8 │   8 │
+│        2 │    9 │  17 │
+│        2 │   10 │  27 │
+│        2 │   11 │  38 │
+│        3 │   12 │  12 │
+│        3 │   13 │  25 │
+│        3 │   14 │  39 │
+└──────────┴──────┴─────┘
+```
+
+As you can see, `runningAccumulate` merges states for each group of rows separately.
+
+## joinGet {#joinget}
+
+The function lets you extract data from the table the same way as from a [dictionary](../../sql-reference/dictionaries/index.md).
+
+Gets data from [Join](../../engines/table-engines/special/join.md#creating-a-table) tables using the specified join key.
+
+Only supports tables created with the `ENGINE = Join(ANY, LEFT, <join_keys>)` statement.
+
+**Syntax**
+
+``` sql
+joinGet(join_storage_table_name, `value_column`, join_keys)
+```
+
+**Arguments**
+
+-   `join_storage_table_name` — an [identifier](../../sql-reference/syntax.md#syntax-identifiers) indicates where search is performed. The identifier is searched in the default database (see parameter `default_database` in the config file). To override the default database, use the `USE db_name` or specify the database and the table through the separator `db_name.db_table`, see the example.
+-   `value_column` — name of the column of the table that contains required data.
+-   `join_keys` — list of keys.
+
+**Returned value**
+
+Returns list of values corresponded to list of keys.
+
+If certain does not exist in source table then `0` or `null` will be returned based on [join_use_nulls](../../operations/settings/settings.md#join_use_nulls) setting.
+
+More info about `join_use_nulls` in [Join operation](../../engines/table-engines/special/join.md).
+
+**Example**
+
+Input table:
+
+``` sql
+CREATE DATABASE db_test
+CREATE TABLE db_test.id_val(`id` UInt32, `val` UInt32) ENGINE = Join(ANY, LEFT, id) SETTINGS join_use_nulls = 1
+INSERT INTO db_test.id_val VALUES (1,11)(2,12)(4,13)
+```
+
+``` text
+┌─id─┬─val─┐
+│  4 │  13 │
+│  2 │  12 │
+│  1 │  11 │
+└────┴─────┘
+```
+
+Query:
+
+``` sql
+SELECT joinGet(db_test.id_val,'val',toUInt32(number)) from numbers(4) SETTINGS join_use_nulls = 1
+```
+
+Result:
+
+``` text
+┌─joinGet(db_test.id_val, 'val', toUInt32(number))─┐
+│                                                0 │
+│                                               11 │
+│                                               12 │
+│                                                0 │
+└──────────────────────────────────────────────────┘
+```
+
+## modelEvaluate(model_name, …) {#function-modelevaluate}
+
+Evaluate external model.
+Accepts a model name and model arguments. Returns Float64.
+
+## throwIf(x\[, custom_message\]) {#throwifx-custom-message}
+
+Throw an exception if the argument is non zero.
+custom_message - is an optional parameter: a constant string, provides an error message
+
+``` sql
+SELECT throwIf(number = 3, 'Too many') FROM numbers(10);
+```
+
+``` text
+↙ Progress: 0.00 rows, 0.00 B (0.00 rows/s., 0.00 B/s.) Received exception from server (version 19.14.1):
+Code: 395. DB::Exception: Received from localhost:9000. DB::Exception: Too many.
+```
+
+## identity {#identity}
+
+Returns the same value that was used as its argument. Used for debugging and testing, allows to cancel using index, and get the query performance of a full scan. When query is analyzed for possible use of index, the analyzer does not look inside `identity` functions. Also constant folding is not applied too.
+
+**Syntax**
+
+``` sql
+identity(x)
+```
+
+**Example**
+
+Query:
+
+``` sql
+SELECT identity(42)
+```
+
+Result:
+
+``` text
+┌─identity(42)─┐
+│           42 │
+└──────────────┘
+```
+
+## randomPrintableASCII {#randomascii}
+
+Generates a string with a random set of [ASCII](https://en.wikipedia.org/wiki/ASCII#Printable_characters) printable characters.
+
+**Syntax**
+
+``` sql
+randomPrintableASCII(length)
+```
+
+**Arguments**
+
+-   `length` — Resulting string length. Positive integer.
+
+        If you pass `length < 0`, behavior of the function is undefined.
+
+**Returned value**
+
+-   String with a random set of [ASCII](https://en.wikipedia.org/wiki/ASCII#Printable_characters) printable characters.
+
+Type: [String](../../sql-reference/data-types/string.md)
+
+**Example**
+
+``` sql
+SELECT number, randomPrintableASCII(30) as str, length(str) FROM system.numbers LIMIT 3
+```
+
+``` text
+┌─number─┬─str────────────────────────────┬─length(randomPrintableASCII(30))─┐
+│      0 │ SuiCOSTvC0csfABSw=UcSzp2.`rv8x │                               30 │
+│      1 │ 1Ag NlJ &RCN:*>HVPG;PE-nO"SUFD │                               30 │
+│      2 │ /"+<"wUTh:=LjJ Vm!c&hI*m#XTfzz │                               30 │
+└────────┴────────────────────────────────┴──────────────────────────────────┘
+```
+
+## randomString {#randomstring}
+
+Generates a binary string of the specified length filled with random bytes (including zero bytes).
+
+**Syntax**
+
+``` sql
+randomString(length)
+```
+
+**Arguments**
+
+-   `length` — String length. Positive integer.
+
+**Returned value**
+
+-   String filled with random bytes.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT randomString(30) AS str, length(str) AS len FROM numbers(2) FORMAT Vertical;
+```
+
+Result:
+
+``` text
+Row 1:
+──────
+str: 3 G  :   pT ?w тi  k aV f6
+len: 30
+
+Row 2:
+──────
+str: 9 ,]    ^   )  ]??  8
+len: 30
+```
+
+**See Also**
+
+-   [generateRandom](../../sql-reference/table-functions/generate.md#generaterandom)
+-   [randomPrintableASCII](../../sql-reference/functions/other-functions.md#randomascii)
+
+
+## randomFixedString {#randomfixedstring}
+
+Generates a binary string of the specified length filled with random bytes (including zero bytes).
+
+**Syntax**
+
+``` sql
+randomFixedString(length);
+```
+
+**Arguments**
+
+-   `length` — String length in bytes. [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Returned value(s)**
+
+-   String filled with random bytes.
+
+Type: [FixedString](../../sql-reference/data-types/fixedstring.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT randomFixedString(13) as rnd, toTypeName(rnd)
+```
+
+Result:
+
+```text
+┌─rnd──────┬─toTypeName(randomFixedString(13))─┐
+│ j▒h㋖HɨZ'▒ │ FixedString(13)                 │
+└──────────┴───────────────────────────────────┘
+
+```
+
+## randomStringUTF8 {#randomstringutf8}
+
+Generates a random string of a specified length. Result string contains valid UTF-8 code points. The value of code points may be outside of the range of assigned Unicode.
+
+**Syntax**
+
+``` sql
+randomStringUTF8(length);
+```
+
+**Arguments**
+
+-   `length` — Required length of the resulting string in code points. [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Returned value(s)**
+
+-   UTF-8 random string.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT randomStringUTF8(13)
+```
+
+Result:
+
+```text
+┌─randomStringUTF8(13)─┐
+│ 𘤗𙉝д兠庇󡅴󱱎󦐪􂕌𔊹𓰛   │
+└──────────────────────┘
+
+```
+
+## getSetting {#getSetting}
+
+Returns the current value of a [custom setting](../../operations/settings/index.md#custom_settings).
+
+**Syntax**
+
+```sql
+getSetting('custom_setting');
+```
+
+**Parameter**
+
+-   `custom_setting` — The setting name. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   The setting current value.
+
+**Example**
+
+```sql
+SET custom_a = 123;
+SELECT getSetting('custom_a');
+```
+
+**Result**
+
+```
+123
+```
+
+**See Also**
+
+-   [Custom Settings](../../operations/settings/index.md#custom_settings)
+
+## isDecimalOverflow {#is-decimal-overflow}
+
+Checks whether the [Decimal](../../sql-reference/data-types/decimal.md) value is out of its (or specified) precision.
+
+**Syntax**
+
+``` sql
+isDecimalOverflow(d, [p])
+```
+
+**Arguments**
+
+-   `d` — value. [Decimal](../../sql-reference/data-types/decimal.md).
+-   `p` — precision. Optional. If omitted, the initial precision of the first argument is used. Using of this paratemer could be helpful for data extraction to another DBMS or file. [UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges).
+
+**Returned values**
+
+-   `1` — Decimal value has more digits then it's precision allow,
+-   `0` — Decimal value satisfies the specified precision.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT isDecimalOverflow(toDecimal32(1000000000, 0), 9),
+       isDecimalOverflow(toDecimal32(1000000000, 0)),
+       isDecimalOverflow(toDecimal32(-1000000000, 0), 9),
+       isDecimalOverflow(toDecimal32(-1000000000, 0));
+```
+
+Result:
+
+``` text
+1	1	1	1
+```
+
+## countDigits {#count-digits}
+
+Returns number of decimal digits you need to represent the value.
+
+**Syntax**
+
+``` sql
+countDigits(x)
+```
+
+**Arguments**
+
+-   `x` — [Int](../../sql-reference/data-types/int-uint.md) or [Decimal](../../sql-reference/data-types/decimal.md) value.
+
+**Returned value**
+
+Number of digits.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges).
+
+:::note    
+For `Decimal` values takes into account their scales: calculates result over underlying integer type which is `(value * scale)`. For example: `countDigits(42) = 2`, `countDigits(42.000) = 5`, `countDigits(0.04200) = 4`. I.e. you may check decimal overflow for `Decimal64` with `countDecimal(x) > 18`. It's a slow variant of [isDecimalOverflow](#is-decimal-overflow).
+:::
+
+**Example**
+
+Query:
+
+``` sql
+SELECT countDigits(toDecimal32(1, 9)), countDigits(toDecimal32(-1, 9)),
+       countDigits(toDecimal64(1, 18)), countDigits(toDecimal64(-1, 18)),
+       countDigits(toDecimal128(1, 38)), countDigits(toDecimal128(-1, 38));
+```
+
+Result:
+
+``` text
+10	10	19	19	39	39
+```
+
+## errorCodeToName {#error-code-to-name}
+
+**Returned value**
+
+-   Variable name for the error code.
+
+Type: [LowCardinality(String)](../../sql-reference/data-types/lowcardinality.md).
+
+**Syntax**
+
+``` sql
+errorCodeToName(1)
+```
+
+Result:
+
+``` text
+UNSUPPORTED_METHOD
+```
+
+## tcpPort {#tcpPort}
+
+Returns [native interface](../../interfaces/tcp.md) TCP port number listened by this server.
+If it is executed in the context of a distributed table, then it generates a normal column, otherwise it produces a constant value.
+
+**Syntax**
+
+``` sql
+tcpPort()
+```
+
+**Arguments**
+
+-   None.
+
+**Returned value**
+
+-   The TCP port number.
+
+Type: [UInt16](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT tcpPort();
+```
+
+Result:
+
+``` text
+┌─tcpPort()─┐
+│      9000 │
+└───────────┘
+```
+
+**See Also**
+
+-   [tcp_port](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-tcp_port)
+
+## currentProfiles {#current-profiles}
+
+Returns a list of the current [settings profiles](../../operations/access-rights.md#settings-profiles-management) for the current user. 
+
+The command [SET PROFILE](../../sql-reference/statements/set.md#query-set) could be used to change the current setting profile. If the command `SET PROFILE` was not used the function returns the profiles specified at the current user's definition (see [CREATE USER](../../sql-reference/statements/create/user.md#create-user-statement)).
+
+**Syntax**
+
+``` sql
+currentProfiles()
+```
+
+**Returned value**
+
+-   List of the current user settings profiles. 
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+## enabledProfiles {#enabled-profiles}
+
+ Returns settings profiles, assigned to the current user both explicitly and implicitly. Explicitly assigned profiles are the same as returned by the [currentProfiles](#current-profiles) function. Implicitly assigned profiles include parent profiles of other assigned profiles, profiles assigned via granted roles, profiles assigned via their own settings, and the main default profile (see the `default_profile` section in the main server configuration file).
+
+**Syntax**
+
+``` sql
+enabledProfiles()
+```
+
+**Returned value**
+
+-   List of the enabled settings profiles. 
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+## defaultProfiles {#default-profiles}
+
+Returns all the profiles specified at the current user's definition (see [CREATE USER](../../sql-reference/statements/create/user.md#create-user-statement) statement).
+
+**Syntax**
+
+``` sql
+defaultProfiles()
+```
+
+**Returned value**
+
+-   List of the default settings profiles. 
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+## currentRoles {#current-roles}
+
+Returns the names of the roles which are current for the current user. The current roles can be changed by the [SET ROLE](../../sql-reference/statements/set-role.md#set-role-statement) statement. If the `SET ROLE` statement was not used, the function `currentRoles` returns the same as `defaultRoles`.
+
+**Syntax**
+
+``` sql
+currentRoles()
+```
+
+**Returned value**
+
+-   List of the current roles for the current user. 
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+## enabledRoles {#enabled-roles}
+
+Returns the names of the current roles and the roles, granted to some of the current roles.
+
+**Syntax**
+
+``` sql
+enabledRoles()
+```
+
+**Returned value**
+
+-   List of the enabled roles for the current user. 
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+## defaultRoles {#default-roles}
+
+Returns the names of the roles which are enabled by default for the current user when he logins. Initially these are all roles granted to the current user (see [GRANT](../../sql-reference/statements/grant/#grant-select)), but that can be changed with the [SET DEFAULT ROLE](../../sql-reference/statements/set-role.md#set-default-role-statement) statement. 
+
+**Syntax**
+
+``` sql
+defaultRoles()
+```
+
+**Returned value**
+
+-   List of the default roles for the current user. 
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+## getServerPort {#getserverport}
+
+Returns the number of the server port. When the port is not used by the server, throws an exception.
+
+**Syntax**
+
+``` sql
+getServerPort(port_name)
+```
+
+**Arguments**
+
+-   `port_name` — The name of the server port. [String](../../sql-reference/data-types/string.md#string). Possible values:
+
+    -   'tcp_port'
+    -   'tcp_port_secure'
+    -   'http_port'
+    -   'https_port'
+    -   'interserver_http_port'
+    -   'interserver_https_port'
+    -   'mysql_port'
+    -   'postgresql_port'
+    -   'grpc_port'
+    -   'prometheus.port'
+
+**Returned value**
+
+-   The number of the server port.
+
+Type: [UInt16](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT getServerPort('tcp_port');
+```
+
+Result:
+
+``` text
+┌─getServerPort('tcp_port')─┐
+│ 9000                      │
+└───────────────────────────┘
+```
+
+## queryID {#query-id}
+
+Returns the ID of the current query. Other parameters of a query can be extracted from the [system.query_log](../../operations/system-tables/query_log.md) table via `query_id`.
+
+In contrast to [initialQueryID](#initial-query-id) function, `queryID` can return different results on different shards (see example).
+
+**Syntax**
+
+``` sql
+queryID()
+```
+
+**Returned value**
+
+-   The ID of the current query.
+
+Type: [String](../../sql-reference/data-types/string.md)
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE tmp (str String) ENGINE = Log;
+INSERT INTO tmp (*) VALUES ('a');
+SELECT count(DISTINCT t) FROM (SELECT queryID() AS t FROM remote('127.0.0.{1..3}', currentDatabase(), 'tmp') GROUP BY queryID());
+```
+
+Result:
+
+``` text
+┌─count()─┐
+│ 3       │
+└─────────┘
+```
+
+## initialQueryID {#initial-query-id}
+
+Returns the ID of the initial current query. Other parameters of a query can be extracted from the [system.query_log](../../operations/system-tables/query_log.md) table via `initial_query_id`.
+
+In contrast to [queryID](#query-id) function, `initialQueryID` returns the same results on different shards (see example).
+
+**Syntax**
+
+``` sql
+initialQueryID()
+```
+
+**Returned value**
+
+-   The ID of the initial current query.
+
+Type: [String](../../sql-reference/data-types/string.md)
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE tmp (str String) ENGINE = Log;
+INSERT INTO tmp (*) VALUES ('a');
+SELECT count(DISTINCT t) FROM (SELECT initialQueryID() AS t FROM remote('127.0.0.{1..3}', currentDatabase(), 'tmp') GROUP BY queryID());
+```
+
+Result:
+
+``` text
+┌─count()─┐
+│ 1       │
+└─────────┘
+```
+
+## shardNum {#shard-num}
+
+Returns the index of a shard which processes a part of data for a distributed query. Indices are started from `1`.
+If a query is not distributed then constant value `0` is returned.
+
+**Syntax**
+
+``` sql
+shardNum()
+```
+
+**Returned value**
+
+-   Shard index or constant `0`.
+
+Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+In the following example a configuration with two shards is used. The query is executed on the [system.one](../../operations/system-tables/one.md) table on every shard.
+
+Query:
+
+``` sql
+CREATE TABLE shard_num_example (dummy UInt8) 
+    ENGINE=Distributed(test_cluster_two_shards_localhost, system, one, dummy);
+SELECT dummy, shardNum(), shardCount() FROM shard_num_example;
+```
+
+Result:
+
+``` text
+┌─dummy─┬─shardNum()─┬─shardCount()─┐
+│     0 │          2 │            2 │
+│     0 │          1 │            2 │
+└───────┴────────────┴──────────────┘
+```
+
+**See Also**
+
+-   [Distributed Table Engine](../../engines/table-engines/special/distributed.md)
+
+## shardCount {#shard-count}
+
+Returns the total number of shards for a distributed query.
+If a query is not distributed then constant value `0` is returned.
+
+**Syntax**
+
+``` sql
+shardCount()
+```
+
+**Returned value**
+
+-   Total number of shards or `0`.
+
+Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+
+**See Also**
+
+- [shardNum()](#shard-num) function example also contains `shardCount()` function call.
+
+## getOSKernelVersion {#getoskernelversion}
+
+Returns a string with the current OS kernel version.
+
+**Syntax**
+
+``` sql
+getOSKernelVersion()
+```
+
+**Arguments**
+
+-   None.
+
+**Returned value**
+
+-   The current OS kernel version.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT getOSKernelVersion();
+```
+
+Result:
+
+``` text
+┌─getOSKernelVersion()────┐
+│ Linux 4.15.0-55-generic │
+└─────────────────────────┘
+```
+
+## zookeeperSessionUptime {#zookeepersessionuptime}
+
+Returns the uptime of the current ZooKeeper session in seconds.
+
+**Syntax**
+
+``` sql
+zookeeperSessionUptime()
+```
+
+**Arguments**
+
+-   None.
+
+**Returned value**
+
+-   Uptime of the current ZooKeeper session in seconds.
+
+Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT zookeeperSessionUptime();
+```
+
+Result:
+
+``` text
+┌─zookeeperSessionUptime()─┐
+│                      286 │
+└──────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/random-functions.md b/docs/en/reference/sql-reference/functions/random-functions.md
new file mode 100644
index 00000000000..5e20a93da1f
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/random-functions.md
@@ -0,0 +1,105 @@
+---
+sidebar_position: 51
+sidebar_label: Pseudo-Random Numbers
+---
+
+# Functions for Generating Pseudo-Random Numbers {#functions-for-generating-pseudo-random-numbers}
+
+All the functions accept zero arguments or one argument. If an argument is passed, it can be any type, and its value is not used for anything. The only purpose of this argument is to prevent common subexpression elimination, so that two different instances of the same function return different columns with different random numbers.
+
+:::note    
+Non-cryptographic generators of pseudo-random numbers are used.
+:::
+
+## rand, rand32 {#rand}
+
+Returns a pseudo-random UInt32 number, evenly distributed among all UInt32-type numbers.
+
+Uses a linear congruential generator.
+
+## rand64 {#rand64}
+
+Returns a pseudo-random UInt64 number, evenly distributed among all UInt64-type numbers.
+
+Uses a linear congruential generator.
+
+## randConstant {#randconstant}
+
+Produces a constant column with a random value.
+
+**Syntax**
+
+``` sql
+randConstant([x])
+```
+
+**Arguments**
+
+-   `x` — [Expression](../../sql-reference/syntax.md#syntax-expressions) resulting in any of the [supported data types](../../sql-reference/data-types/index.md#data_types). The resulting value is discarded, but the expression itself if used for bypassing [common subexpression elimination](../../sql-reference/functions/index.md#common-subexpression-elimination) if the function is called multiple times in one query. Optional parameter.
+
+**Returned value**
+
+-   Pseudo-random number.
+
+Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT rand(), rand(1), rand(number), randConstant(), randConstant(1), randConstant(number)
+FROM numbers(3)
+```
+
+Result:
+
+``` text
+┌─────rand()─┬────rand(1)─┬─rand(number)─┬─randConstant()─┬─randConstant(1)─┬─randConstant(number)─┐
+│ 3047369878 │ 4132449925 │   4044508545 │     2740811946 │      4229401477 │           1924032898 │
+│ 2938880146 │ 1267722397 │   4154983056 │     2740811946 │      4229401477 │           1924032898 │
+│  956619638 │ 4238287282 │   1104342490 │     2740811946 │      4229401477 │           1924032898 │
+└────────────┴────────────┴──────────────┴────────────────┴─────────────────┴──────────────────────┘
+```
+
+# Random Functions for Working with Strings {#random-functions-for-working-with-strings}
+
+## randomString {#random-string}
+
+## randomFixedString {#random-fixed-string}
+
+## randomPrintableASCII {#random-printable-ascii}
+
+## randomStringUTF8 {#random-string-utf8}
+
+## fuzzBits {#fuzzbits}
+
+**Syntax**
+
+``` sql
+fuzzBits([s], [prob])
+```
+
+Inverts bits of `s`, each with probability `prob`.
+
+**Arguments**
+- `s` - `String` or `FixedString`
+- `prob` - constant `Float32/64`
+
+**Returned value**
+Fuzzed string with same as s type.
+
+**Example**
+
+``` sql
+SELECT fuzzBits(materialize('abacaba'), 0.1)
+FROM numbers(3)
+```
+
+\`\`\` text
+┌─fuzzBits(materialize(‘abacaba’), 0.1)─┐
+│ abaaaja │
+│ a\*cjab+ │
+│ aeca2A │
+└───────────────────────────────────────┘
+
diff --git a/docs/en/reference/sql-reference/functions/rounding-functions.md b/docs/en/reference/sql-reference/functions/rounding-functions.md
new file mode 100644
index 00000000000..a469318e623
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/rounding-functions.md
@@ -0,0 +1,201 @@
+---
+sidebar_position: 45
+sidebar_label: Rounding
+---
+
+# Rounding Functions {#rounding-functions}
+
+## floor(x\[, N\]) {#floorx-n}
+
+Returns the largest round number that is less than or equal to `x`. A round number is a multiple of 1/10N, or the nearest number of the appropriate data type if 1 / 10N isn’t exact.
+‘N’ is an integer constant, optional parameter. By default it is zero, which means to round to an integer.
+‘N’ may be negative.
+
+Examples: `floor(123.45, 1) = 123.4, floor(123.45, -1) = 120.`
+
+`x` is any numeric type. The result is a number of the same type.
+For integer arguments, it makes sense to round with a negative `N` value (for non-negative `N`, the function does not do anything).
+If rounding causes overflow (for example, floor(-128, -1)), an implementation-specific result is returned.
+
+## ceil(x\[, N\]), ceiling(x\[, N\]) {#ceilx-n-ceilingx-n}
+
+Returns the smallest round number that is greater than or equal to `x`. In every other way, it is the same as the `floor` function (see above).
+
+## trunc(x\[, N\]), truncate(x\[, N\]) {#truncx-n-truncatex-n}
+
+Returns the round number with largest absolute value that has an absolute value less than or equal to `x`‘s. In every other way, it is the same as the ’floor’ function (see above).
+
+## round(x\[, N\]) {#rounding_functions-round}
+
+Rounds a value to a specified number of decimal places.
+
+The function returns the nearest number of the specified order. In case when given number has equal distance to surrounding numbers, the function uses banker’s rounding for float number types and rounds away from zero for the other number types (Decimal).
+
+``` sql
+round(expression [, decimal_places])
+```
+
+**Arguments**
+
+-   `expression` — A number to be rounded. Can be any [expression](../../sql-reference/syntax.md#syntax-expressions) returning the numeric [data type](../../sql-reference/data-types/index.md#data_types).
+-   `decimal-places` — An integer value.
+    -   If `decimal-places > 0` then the function rounds the value to the right of the decimal point.
+    -   If `decimal-places < 0` then the function rounds the value to the left of the decimal point.
+    -   If `decimal-places = 0` then the function rounds the value to integer. In this case the argument can be omitted.
+
+**Returned value:**
+
+The rounded number of the same type as the input number.
+
+### Examples {#examples}
+
+**Example of use with Float**
+
+``` sql
+SELECT number / 2 AS x, round(x) FROM system.numbers LIMIT 3
+```
+
+``` text
+┌───x─┬─round(divide(number, 2))─┐
+│   0 │                        0 │
+│ 0.5 │                        0 │
+│   1 │                        1 │
+└─────┴──────────────────────────┘
+```
+
+**Example of use with Decimal**
+
+``` sql
+SELECT cast(number / 2 AS  Decimal(10,4)) AS x, round(x) FROM system.numbers LIMIT 3
+```
+
+``` text
+┌──────x─┬─round(CAST(divide(number, 2), 'Decimal(10, 4)'))─┐
+│ 0.0000 │                                           0.0000 │
+│ 0.5000 │                                           1.0000 │
+│ 1.0000 │                                           1.0000 │
+└────────┴──────────────────────────────────────────────────┘
+```
+
+**Examples of rounding**
+
+Rounding to the nearest number.
+
+``` text
+round(3.2, 0) = 3
+round(4.1267, 2) = 4.13
+round(22,-1) = 20
+round(467,-2) = 500
+round(-467,-2) = -500
+```
+
+Banker’s rounding.
+
+``` text
+round(3.5) = 4
+round(4.5) = 4
+round(3.55, 1) = 3.6
+round(3.65, 1) = 3.6
+```
+
+**See Also**
+
+-   [roundBankers](#roundbankers)
+
+## roundBankers {#roundbankers}
+
+Rounds a number to a specified decimal position.
+
+-   If the rounding number is halfway between two numbers, the function uses banker’s rounding.
+
+        Banker's rounding is a method of rounding fractional numbers. When the rounding number is halfway between two numbers, it's rounded to the nearest even digit at the specified decimal position. For example: 3.5 rounds up to 4, 2.5 rounds down to 2.
+
+        It's the default rounding method for floating point numbers defined in [IEEE 754](https://en.wikipedia.org/wiki/IEEE_754#Roundings_to_nearest). The [round](#rounding_functions-round) function performs the same rounding for floating point numbers. The `roundBankers` function also rounds integers the same way, for example, `roundBankers(45, -1) = 40`.
+
+-   In other cases, the function rounds numbers to the nearest integer.
+
+Using banker’s rounding, you can reduce the effect that rounding numbers has on the results of summing or subtracting these numbers.
+
+For example, sum numbers 1.5, 2.5, 3.5, 4.5 with different rounding:
+
+-   No rounding: 1.5 + 2.5 + 3.5 + 4.5 = 12.
+-   Banker’s rounding: 2 + 2 + 4 + 4 = 12.
+-   Rounding to the nearest integer: 2 + 3 + 4 + 5 = 14.
+
+**Syntax**
+
+``` sql
+roundBankers(expression [, decimal_places])
+```
+
+**Arguments**
+
+-   `expression` — A number to be rounded. Can be any [expression](../../sql-reference/syntax.md#syntax-expressions) returning the numeric [data type](../../sql-reference/data-types/index.md#data_types).
+-   `decimal-places` — Decimal places. An integer number.
+    -   `decimal-places > 0` — The function rounds the number to the given position right of the decimal point. Example: `roundBankers(3.55, 1) = 3.6`.
+    -   `decimal-places < 0` — The function rounds the number to the given position left of the decimal point. Example: `roundBankers(24.55, -1) = 20`.
+    -   `decimal-places = 0` — The function rounds the number to an integer. In this case the argument can be omitted. Example: `roundBankers(2.5) = 2`.
+
+**Returned value**
+
+A value rounded by the banker’s rounding method.
+
+### Examples {#examples-1}
+
+**Example of use**
+
+Query:
+
+``` sql
+ SELECT number / 2 AS x, roundBankers(x, 0) AS b fROM system.numbers limit 10
+```
+
+Result:
+
+``` text
+┌───x─┬─b─┐
+│   0 │ 0 │
+│ 0.5 │ 0 │
+│   1 │ 1 │
+│ 1.5 │ 2 │
+│   2 │ 2 │
+│ 2.5 │ 2 │
+│   3 │ 3 │
+│ 3.5 │ 4 │
+│   4 │ 4 │
+│ 4.5 │ 4 │
+└─────┴───┘
+```
+
+**Examples of Banker’s rounding**
+
+``` text
+roundBankers(0.4) = 0
+roundBankers(-3.5) = -4
+roundBankers(4.5) = 4
+roundBankers(3.55, 1) = 3.6
+roundBankers(3.65, 1) = 3.6
+roundBankers(10.35, 1) = 10.4
+roundBankers(10.755, 2) = 10.76
+```
+
+**See Also**
+
+-   [round](#rounding_functions-round)
+
+## roundToExp2(num) {#roundtoexp2num}
+
+Accepts a number. If the number is less than one, it returns 0. Otherwise, it rounds the number down to the nearest (whole non-negative) degree of two.
+
+## roundDuration(num) {#rounddurationnum}
+
+Accepts a number. If the number is less than one, it returns 0. Otherwise, it rounds the number down to numbers from the set: 1, 10, 30, 60, 120, 180, 240, 300, 600, 1200, 1800, 3600, 7200, 18000, 36000. 
+
+## roundAge(num) {#roundagenum}
+
+Accepts a number. If the number is less than 18, it returns 0. Otherwise, it rounds the number down to a number from the set: 18, 25, 35, 45, 55. 
+
+## roundDown(num, arr) {#rounddownnum-arr}
+
+Accepts a number and rounds it down to an element in the specified array. If the value is less than the lowest bound, the lowest bound is returned.
+
diff --git a/docs/en/reference/sql-reference/functions/splitting-merging-functions.md b/docs/en/reference/sql-reference/functions/splitting-merging-functions.md
new file mode 100644
index 00000000000..7e94c225f6b
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/splitting-merging-functions.md
@@ -0,0 +1,339 @@
+---
+sidebar_position: 47
+sidebar_label: Splitting and Merging Strings and Arrays
+---
+
+# Functions for Splitting and Merging Strings and Arrays {#functions-for-splitting-and-merging-strings-and-arrays}
+
+## splitByChar(separator, s) {#splitbycharseparator-s}
+
+Splits a string into substrings separated by a specified character. It uses a constant string `separator` which consisting of exactly one character.
+Returns an array of selected substrings. Empty substrings may be selected if the separator occurs at the beginning or end of the string, or if there are multiple consecutive separators.
+
+**Syntax**
+
+``` sql
+splitByChar(separator, s)
+```
+
+**Arguments**
+
+-   `separator` — The separator which should contain exactly one character. [String](../../sql-reference/data-types/string.md).
+-   `s` — The string to split. [String](../../sql-reference/data-types/string.md).
+
+**Returned value(s)**
+
+Returns an array of selected substrings. Empty substrings may be selected when:
+
+-   A separator occurs at the beginning or end of the string;
+-   There are multiple consecutive separators;
+-   The original string `s` is empty.
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+**Example**
+
+``` sql
+SELECT splitByChar(',', '1,2,3,abcde');
+```
+
+``` text
+┌─splitByChar(',', '1,2,3,abcde')─┐
+│ ['1','2','3','abcde']           │
+└─────────────────────────────────┘
+```
+
+## splitByString(separator, s) {#splitbystringseparator-s}
+
+Splits a string into substrings separated by a string. It uses a constant string `separator` of multiple characters as the separator. If the string `separator` is empty, it will split the string `s` into an array of single characters.
+
+**Syntax**
+
+``` sql
+splitByString(separator, s)
+```
+
+**Arguments**
+
+-   `separator` — The separator. [String](../../sql-reference/data-types/string.md).
+-   `s` — The string to split. [String](../../sql-reference/data-types/string.md).
+
+**Returned value(s)**
+
+Returns an array of selected substrings. Empty substrings may be selected when:
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+-   A non-empty separator occurs at the beginning or end of the string;
+-   There are multiple consecutive non-empty separators;
+-   The original string `s` is empty while the separator is not empty.
+
+**Example**
+
+``` sql
+SELECT splitByString(', ', '1, 2 3, 4,5, abcde');
+```
+
+``` text
+┌─splitByString(', ', '1, 2 3, 4,5, abcde')─┐
+│ ['1','2 3','4,5','abcde']                 │
+└───────────────────────────────────────────┘
+```
+
+``` sql
+SELECT splitByString('', 'abcde');
+```
+
+``` text
+┌─splitByString('', 'abcde')─┐
+│ ['a','b','c','d','e']      │
+└────────────────────────────┘
+```
+
+## splitByRegexp(regexp, s) {#splitbyregexpseparator-s}
+
+Splits a string into substrings separated by a regular expression. It uses a regular expression string `regexp` as the separator. If the `regexp` is empty, it will split the string `s` into an array of single characters. If no match is found for this regular expression, the string `s` won't be split.
+
+**Syntax**
+
+``` sql
+splitByRegexp(regexp, s)
+```
+
+**Arguments**
+
+-   `regexp` — Regular expression. Constant. [String](../data-types/string.md) or [FixedString](../data-types/fixedstring.md).
+-   `s` — The string to split. [String](../../sql-reference/data-types/string.md).
+
+**Returned value(s)**
+
+Returns an array of selected substrings. Empty substrings may be selected when:
+
+-   A non-empty regular expression match occurs at the beginning or end of the string;
+-   There are multiple consecutive non-empty regular expression matches;
+-   The original string `s` is empty while the regular expression is not empty.
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT splitByRegexp('\\d+', 'a12bc23de345f');
+```
+
+Result:
+
+``` text
+┌─splitByRegexp('\\d+', 'a12bc23de345f')─┐
+│ ['a','bc','de','f']                    │
+└────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT splitByRegexp('', 'abcde');
+```
+
+Result:
+
+``` text
+┌─splitByRegexp('', 'abcde')─┐
+│ ['a','b','c','d','e']      │
+└────────────────────────────┘
+```
+
+## splitByWhitespace(s) {#splitbywhitespaceseparator-s}
+
+Splits a string into substrings separated by whitespace characters. 
+Returns an array of selected substrings.
+
+**Syntax**
+
+``` sql
+splitByWhitespace(s)
+```
+
+**Arguments**
+
+-   `s` — The string to split. [String](../../sql-reference/data-types/string.md).
+
+**Returned value(s)**
+
+Returns an array of selected substrings.
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+**Example**
+
+``` sql
+SELECT splitByWhitespace('  1!  a,  b.  ');
+```
+
+``` text
+┌─splitByWhitespace('  1!  a,  b.  ')─┐
+│ ['1!','a,','b.']                    │
+└─────────────────────────────────────┘
+```
+
+## splitByNonAlpha(s) {#splitbynonalphaseparator-s}
+
+Splits a string into substrings separated by whitespace and punctuation characters. 
+Returns an array of selected substrings.
+
+**Syntax**
+
+``` sql
+splitByNonAlpha(s)
+```
+
+**Arguments**
+
+-   `s` — The string to split. [String](../../sql-reference/data-types/string.md).
+
+**Returned value(s)**
+
+Returns an array of selected substrings.
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+**Example**
+
+``` sql
+SELECT splitByNonAlpha('  1!  a,  b.  ');
+```
+
+``` text
+┌─splitByNonAlpha('  1!  a,  b.  ')─┐
+│ ['1','a','b']                     │
+└───────────────────────────────────┘
+```
+
+## arrayStringConcat(arr\[, separator\]) {#arraystringconcatarr-separator}
+
+Concatenates string representations of values listed in the array with the separator. `separator` is an optional parameter: a constant string, set to an empty string by default.
+Returns the string.
+
+## alphaTokens(s) {#alphatokenss}
+
+Selects substrings of consecutive bytes from the ranges a-z and A-Z.Returns an array of substrings.
+
+**Example**
+
+``` sql
+SELECT alphaTokens('abca1abc');
+```
+
+``` text
+┌─alphaTokens('abca1abc')─┐
+│ ['abca','abc']          │
+└─────────────────────────┘
+```
+
+## extractAllGroups(text, regexp) {#extractallgroups}
+
+Extracts all groups from non-overlapping substrings matched by a regular expression.
+
+**Syntax**
+
+``` sql
+extractAllGroups(text, regexp)
+```
+
+**Arguments**
+
+-   `text` — [String](../data-types/string.md) or [FixedString](../data-types/fixedstring.md).
+-   `regexp` — Regular expression. Constant. [String](../data-types/string.md) or [FixedString](../data-types/fixedstring.md).
+
+**Returned values**
+
+-   If the function finds at least one matching group, it returns `Array(Array(String))` column, clustered by group_id (1 to N, where N is number of capturing groups in `regexp`).
+
+-   If there is no matching group, returns an empty array.
+
+Type: [Array](../data-types/array.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT extractAllGroups('abc=123, 8="hkl"', '("[^"]+"|\\w+)=("[^"]+"|\\w+)');
+```
+
+Result:
+
+``` text
+┌─extractAllGroups('abc=123, 8="hkl"', '("[^"]+"|\\w+)=("[^"]+"|\\w+)')─┐
+│ [['abc','123'],['8','"hkl"']]                                         │
+└───────────────────────────────────────────────────────────────────────┘
+```
+
+## ngrams {#ngrams}
+
+Splits the UTF-8 string into n-grams of `ngramsize` symbols.
+
+**Syntax** 
+
+``` sql
+ngrams(string, ngramsize)
+```
+
+**Arguments**
+
+-   `string` — String. [String](../../sql-reference/data-types/string.md) or [FixedString](../../sql-reference/data-types/fixedstring.md).
+-   `ngramsize` — The size of an n-gram. [UInt](../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Array with n-grams.
+
+Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT ngrams('ClickHouse', 3);
+```
+
+Result:
+
+``` text
+┌─ngrams('ClickHouse', 3)───────────────────────────┐
+│ ['Cli','lic','ick','ckH','kHo','Hou','ous','use'] │
+└───────────────────────────────────────────────────┘
+```
+
+## tokens {#tokens}
+
+Splits a string into tokens using non-alphanumeric ASCII characters as separators.
+
+**Arguments**
+
+-   `input_string` — Any set of bytes represented as the [String](../../sql-reference/data-types/string.md) data type object.
+
+**Returned value**
+
+-   The resulting array of tokens from input string.
+
+Type: [Array](../data-types/array.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT tokens('test1,;\\ test2,;\\ test3,;\\   test4') AS tokens;
+```
+
+Result:
+
+``` text
+┌─tokens────────────────────────────┐
+│ ['test1','test2','test3','test4'] │
+└───────────────────────────────────┘
+```
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/functions/string-functions.md b/docs/en/reference/sql-reference/functions/string-functions.md
new file mode 100644
index 00000000000..d63e466a836
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/string-functions.md
@@ -0,0 +1,1077 @@
+---
+sidebar_position: 40
+sidebar_label: Strings
+---
+
+# Functions for Working with Strings {#functions-for-working-with-strings}
+
+:::note    
+Functions for [searching](../../sql-reference/functions/string-search-functions.md) and [replacing](../../sql-reference/functions/string-replace-functions.md) in strings are described separately.
+:::
+
+## empty {#empty}
+
+Checks whether the input string is empty.
+
+**Syntax**
+
+``` sql
+empty(x)
+```
+
+A string is considered non-empty if it contains at least one byte, even if this is a space or a null byte.
+
+The function also works for [arrays](array-functions.md#function-empty) or [UUID](uuid-functions.md#empty).
+
+**Arguments**
+
+-   `x` — Input value. [String](../data-types/string.md).
+
+**Returned value**
+
+-   Returns `1` for an empty string or `0` for a non-empty string.
+
+Type: [UInt8](../data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT empty('');
+```
+
+Result:
+
+```text
+┌─empty('')─┐
+│         1 │
+└───────────┘
+```
+
+## notEmpty {#notempty}
+
+Checks whether the input string is non-empty.
+
+**Syntax**
+
+``` sql
+notEmpty(x)
+```
+
+A string is considered non-empty if it contains at least one byte, even if this is a space or a null byte.
+
+The function also works for [arrays](array-functions.md#function-notempty) or [UUID](uuid-functions.md#notempty).
+
+**Arguments**
+
+-   `x` — Input value. [String](../data-types/string.md).
+
+**Returned value**
+
+-   Returns `1` for a non-empty string or `0` for an empty string string.
+
+Type: [UInt8](../data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT notEmpty('text');
+```
+
+Result:
+
+```text
+┌─notEmpty('text')─┐
+│                1 │
+└──────────────────┘
+```
+
+## length {#length}
+
+Returns the length of a string in bytes (not in characters, and not in code points).
+The result type is UInt64.
+The function also works for arrays.
+
+## lengthUTF8 {#lengthutf8}
+
+Returns the length of a string in Unicode code points (not in characters), assuming that the string contains a set of bytes that make up UTF-8 encoded text. If this assumption is not met, it returns some result (it does not throw an exception).
+The result type is UInt64.
+
+## char_length, CHAR_LENGTH {#char-length}
+
+Returns the length of a string in Unicode code points (not in characters), assuming that the string contains a set of bytes that make up UTF-8 encoded text. If this assumption is not met, it returns some result (it does not throw an exception).
+The result type is UInt64.
+
+## character_length, CHARACTER_LENGTH {#character-length}
+
+Returns the length of a string in Unicode code points (not in characters), assuming that the string contains a set of bytes that make up UTF-8 encoded text. If this assumption is not met, it returns some result (it does not throw an exception).
+The result type is UInt64.
+
+## leftPad {#leftpad}
+
+Pads the current string from the left with spaces or a specified string (multiple times, if needed) until the resulting string reaches the given length. Similarly to the MySQL `LPAD` function.
+
+**Syntax**
+
+``` sql
+leftPad('string', 'length'[, 'pad_string'])
+```
+
+**Arguments**
+
+-   `string` — Input string that needs to be padded. [String](../data-types/string.md).
+-   `length` — The length of the resulting string. [UInt](../data-types/int-uint.md). If the value is less than the input string length, then the input string is returned as-is.
+-   `pad_string` — The string to pad the input string with. [String](../data-types/string.md). Optional. If not specified, then the input string is padded with spaces.
+
+**Returned value**
+
+-   The resulting string of the given length.
+
+Type: [String](../data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT leftPad('abc', 7, '*'), leftPad('def', 7);
+```
+
+Result:
+
+``` text
+┌─leftPad('abc', 7, '*')─┬─leftPad('def', 7)─┐
+│ ****abc                │     def           │
+└────────────────────────┴───────────────────┘
+```
+
+## leftPadUTF8 {#leftpadutf8}
+
+Pads the current string from the left with spaces or a specified string (multiple times, if needed) until the resulting string reaches the given length. Similarly to the MySQL `LPAD` function. While in the [leftPad](#leftpad) function the length is measured in bytes, here in the `leftPadUTF8` function it is measured in code points.
+
+**Syntax**
+
+``` sql
+leftPadUTF8('string','length'[, 'pad_string'])
+```
+
+**Arguments**
+
+-   `string` — Input string that needs to be padded. [String](../data-types/string.md).
+-   `length` — The length of the resulting string. [UInt](../data-types/int-uint.md). If the value is less than the input string length, then the input string is returned as-is.
+-   `pad_string` — The string to pad the input string with. [String](../data-types/string.md). Optional. If not specified, then the input string is padded with spaces.
+
+**Returned value**
+
+-   The resulting string of the given length.
+
+Type: [String](../data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT leftPadUTF8('абвг', 7, '*'), leftPadUTF8('дежз', 7);
+```
+
+Result:
+
+``` text
+┌─leftPadUTF8('абвг', 7, '*')─┬─leftPadUTF8('дежз', 7)─┐
+│ ***абвг                     │    дежз                │
+└─────────────────────────────┴────────────────────────┘
+```
+
+## rightPad {#rightpad}
+
+Pads the current string from the right with spaces or a specified string (multiple times, if needed) until the resulting string reaches the given length. Similarly to the MySQL `RPAD` function.
+
+**Syntax**
+
+``` sql
+rightPad('string', 'length'[, 'pad_string'])
+```
+
+**Arguments**
+
+-   `string` — Input string that needs to be padded. [String](../data-types/string.md).
+-   `length` — The length of the resulting string. [UInt](../data-types/int-uint.md). If the value is less than the input string length, then the input string is returned as-is.
+-   `pad_string` — The string to pad the input string with. [String](../data-types/string.md). Optional. If not specified, then the input string is padded with spaces.
+
+**Returned value**
+
+-   The resulting string of the given length.
+
+Type: [String](../data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT rightPad('abc', 7, '*'), rightPad('abc', 7);
+```
+
+Result:
+
+``` text
+┌─rightPad('abc', 7, '*')─┬─rightPad('abc', 7)─┐
+│ abc****                 │ abc                │
+└─────────────────────────┴────────────────────┘
+```
+
+## rightPadUTF8 {#rightpadutf8}
+
+Pads the current string from the right with spaces or a specified string (multiple times, if needed) until the resulting string reaches the given length. Similarly to the MySQL `RPAD` function. While in the [rightPad](#rightpad) function the length is measured in bytes, here in the `rightPadUTF8` function it is measured in code points.
+
+**Syntax**
+
+``` sql
+rightPadUTF8('string','length'[, 'pad_string'])
+```
+
+**Arguments**
+
+-   `string` — Input string that needs to be padded. [String](../data-types/string.md).
+-   `length` — The length of the resulting string. [UInt](../data-types/int-uint.md). If the value is less than the input string length, then the input string is returned as-is.
+-   `pad_string` — The string to pad the input string with. [String](../data-types/string.md). Optional. If not specified, then the input string is padded with spaces.
+
+**Returned value**
+
+-   The resulting string of the given length.
+
+Type: [String](../data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT rightPadUTF8('абвг', 7, '*'), rightPadUTF8('абвг', 7);
+```
+
+Result:
+
+``` text
+┌─rightPadUTF8('абвг', 7, '*')─┬─rightPadUTF8('абвг', 7)─┐
+│ абвг***                      │ абвг                    │
+└──────────────────────────────┴─────────────────────────┘
+```
+
+## lower, lcase {#lower}
+
+Converts ASCII Latin symbols in a string to lowercase.
+
+## upper, ucase {#upper}
+
+Converts ASCII Latin symbols in a string to uppercase.
+
+## lowerUTF8 {#lowerutf8}
+
+Converts a string to lowercase, assuming the string contains a set of bytes that make up a UTF-8 encoded text.
+It does not detect the language. So for Turkish the result might not be exactly correct.
+If the length of the UTF-8 byte sequence is different for upper and lower case of a code point, the result may be incorrect for this code point.
+If the string contains a set of bytes that is not UTF-8, then the behavior is undefined.
+
+## upperUTF8 {#upperutf8}
+
+Converts a string to uppercase, assuming the string contains a set of bytes that make up a UTF-8 encoded text.
+It does not detect the language. So for Turkish the result might not be exactly correct.
+If the length of the UTF-8 byte sequence is different for upper and lower case of a code point, the result may be incorrect for this code point.
+If the string contains a set of bytes that is not UTF-8, then the behavior is undefined.
+
+## isValidUTF8 {#isvalidutf8}
+
+Returns 1, if the set of bytes is valid UTF-8 encoded, otherwise 0.
+
+## toValidUTF8 {#tovalidutf8}
+
+Replaces invalid UTF-8 characters by the `�` (U+FFFD) character. All running in a row invalid characters are collapsed into the one replacement character.
+
+``` sql
+toValidUTF8(input_string)
+```
+
+**Arguments**
+
+-   `input_string` — Any set of bytes represented as the [String](../../sql-reference/data-types/string.md) data type object.
+
+Returned value: Valid UTF-8 string.
+
+**Example**
+
+``` sql
+SELECT toValidUTF8('\x61\xF0\x80\x80\x80b');
+```
+
+``` text
+┌─toValidUTF8('a����b')─┐
+│ a�b                   │
+└───────────────────────┘
+```
+
+## repeat {#repeat}
+
+Repeats a string as many times as specified and concatenates the replicated values as a single string.
+
+Alias: `REPEAT`.
+
+**Syntax**
+
+``` sql
+repeat(s, n)
+```
+
+**Arguments**
+
+-   `s` — The string to repeat. [String](../../sql-reference/data-types/string.md).
+-   `n` — The number of times to repeat the string. [UInt](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+The single string, which contains the string `s` repeated `n` times. If `n` \< 1, the function returns empty string.
+
+Type: `String`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT repeat('abc', 10);
+```
+
+Result:
+
+``` text
+┌─repeat('abc', 10)──────────────┐
+│ abcabcabcabcabcabcabcabcabcabc │
+└────────────────────────────────┘
+```
+
+## reverse {#reverse}
+
+Reverses the string (as a sequence of bytes).
+
+## reverseUTF8 {#reverseutf8}
+
+Reverses a sequence of Unicode code points, assuming that the string contains a set of bytes representing a UTF-8 text. Otherwise, it does something else (it does not throw an exception).
+
+## format(pattern, s0, s1, …) {#format}
+
+Formatting constant pattern with the string listed in the arguments. `pattern` is a simplified Python format pattern. Format string contains “replacement fields” surrounded by curly braces `{}`. Anything that is not contained in braces is considered literal text, which is copied unchanged to the output. If you need to include a brace character in the literal text, it can be escaped by doubling: `{{ '{{' }}` and `{{ '}}' }}`. Field names can be numbers (starting from zero) or empty (then they are treated as consequence numbers).
+
+``` sql
+SELECT format('{1} {0} {1}', 'World', 'Hello')
+```
+
+``` text
+┌─format('{1} {0} {1}', 'World', 'Hello')─┐
+│ Hello World Hello                       │
+└─────────────────────────────────────────┘
+```
+
+``` sql
+SELECT format('{} {}', 'Hello', 'World')
+```
+
+``` text
+┌─format('{} {}', 'Hello', 'World')─┐
+│ Hello World                       │
+└───────────────────────────────────┘
+```
+
+## concat {#concat}
+
+Concatenates the strings listed in the arguments, without a separator.
+
+**Syntax**
+
+``` sql
+concat(s1, s2, ...)
+```
+
+**Arguments**
+
+Values of type String or FixedString.
+
+**Returned values**
+
+Returns the String that results from concatenating the arguments.
+
+If any of argument values is `NULL`, `concat` returns `NULL`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT concat('Hello, ', 'World!');
+```
+
+Result:
+
+``` text
+┌─concat('Hello, ', 'World!')─┐
+│ Hello, World!               │
+└─────────────────────────────┘
+```
+
+## concatAssumeInjective {#concatassumeinjective}
+
+Same as [concat](#concat), the difference is that you need to ensure that `concat(s1, s2, ...) → sn` is injective, it will be used for optimization of GROUP BY.
+
+The function is named “injective” if it always returns different result for different values of arguments. In other words: different arguments never yield identical result.
+
+**Syntax**
+
+``` sql
+concatAssumeInjective(s1, s2, ...)
+```
+
+**Arguments**
+
+Values of type String or FixedString.
+
+**Returned values**
+
+Returns the String that results from concatenating the arguments.
+
+If any of argument values is `NULL`, `concatAssumeInjective` returns `NULL`.
+
+**Example**
+
+Input table:
+
+``` sql
+CREATE TABLE key_val(`key1` String, `key2` String, `value` UInt32) ENGINE = TinyLog;
+INSERT INTO key_val VALUES ('Hello, ','World',1), ('Hello, ','World',2), ('Hello, ','World!',3), ('Hello',', World!',2);
+SELECT * from key_val;
+```
+
+``` text
+┌─key1────┬─key2─────┬─value─┐
+│ Hello,  │ World    │     1 │
+│ Hello,  │ World    │     2 │
+│ Hello,  │ World!   │     3 │
+│ Hello   │ , World! │     2 │
+└─────────┴──────────┴───────┘
+```
+
+Query:
+
+``` sql
+SELECT concat(key1, key2), sum(value) FROM key_val GROUP BY concatAssumeInjective(key1, key2);
+```
+
+Result:
+
+``` text
+┌─concat(key1, key2)─┬─sum(value)─┐
+│ Hello, World!      │          3 │
+│ Hello, World!      │          2 │
+│ Hello, World       │          3 │
+└────────────────────┴────────────┘
+```
+
+## substring(s, offset, length), mid(s, offset, length), substr(s, offset, length) {#substring}
+
+Returns a substring starting with the byte from the ‘offset’ index that is ‘length’ bytes long. Character indexing starts from one (as in standard SQL). The ‘offset’ and ‘length’ arguments must be constants.
+
+## substringUTF8(s, offset, length) {#substringutf8}
+
+The same as ‘substring’, but for Unicode code points. Works under the assumption that the string contains a set of bytes representing a UTF-8 encoded text. If this assumption is not met, it returns some result (it does not throw an exception).
+
+## appendTrailingCharIfAbsent(s, c) {#appendtrailingcharifabsent}
+
+If the ‘s’ string is non-empty and does not contain the ‘c’ character at the end, it appends the ‘c’ character to the end.
+
+## convertCharset(s, from, to) {#convertcharset}
+
+Returns the string ‘s’ that was converted from the encoding in ‘from’ to the encoding in ‘to’.
+
+## base64Encode(s) {#base64encode}
+
+Encodes ‘s’ string into base64
+
+Alias: `TO_BASE64`.
+
+## base64Decode(s) {#base64decode}
+
+Decode base64-encoded string ‘s’ into original string. In case of failure raises an exception.
+
+Alias: `FROM_BASE64`.
+
+## tryBase64Decode(s) {#trybase64decode}
+
+Similar to base64Decode, but in case of error an empty string would be returned.
+
+## endsWith(s, suffix) {#endswith}
+
+Returns whether to end with the specified suffix. Returns 1 if the string ends with the specified suffix, otherwise it returns 0.
+
+## startsWith(str, prefix) {#startswith}
+
+Returns 1 whether string starts with the specified prefix, otherwise it returns 0.
+
+``` sql
+SELECT startsWith('Spider-Man', 'Spi');
+```
+
+**Returned values**
+
+-   1, if the string starts with the specified prefix.
+-   0, if the string does not start with the specified prefix.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT startsWith('Hello, world!', 'He');
+```
+
+Result:
+
+``` text
+┌─startsWith('Hello, world!', 'He')─┐
+│                                 1 │
+└───────────────────────────────────┘
+```
+
+## trim {#trim}
+
+Removes all specified characters from the start or end of a string.
+By default removes all consecutive occurrences of common whitespace (ASCII character 32) from both ends of a string.
+
+**Syntax**
+
+``` sql
+trim([[LEADING|TRAILING|BOTH] trim_character FROM] input_string)
+```
+
+**Arguments**
+
+-   `trim_character` — Specified characters for trim. [String](../../sql-reference/data-types/string.md).
+-   `input_string` — String for trim. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+A string without leading and (or) trailing specified characters.
+
+Type: `String`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT trim(BOTH ' ()' FROM '(   Hello, world!   )');
+```
+
+Result:
+
+``` text
+┌─trim(BOTH ' ()' FROM '(   Hello, world!   )')─┐
+│ Hello, world!                                 │
+└───────────────────────────────────────────────┘
+```
+
+## trimLeft {#trimleft}
+
+Removes all consecutive occurrences of common whitespace (ASCII character 32) from the beginning of a string. It does not remove other kinds of whitespace characters (tab, no-break space, etc.).
+
+**Syntax**
+
+``` sql
+trimLeft(input_string)
+```
+
+Alias: `ltrim(input_string)`.
+
+**Arguments**
+
+-   `input_string` — string to trim. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+A string without leading common whitespaces.
+
+Type: `String`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT trimLeft('     Hello, world!     ');
+```
+
+Result:
+
+``` text
+┌─trimLeft('     Hello, world!     ')─┐
+│ Hello, world!                       │
+└─────────────────────────────────────┘
+```
+
+## trimRight {#trimright}
+
+Removes all consecutive occurrences of common whitespace (ASCII character 32) from the end of a string. It does not remove other kinds of whitespace characters (tab, no-break space, etc.).
+
+**Syntax**
+
+``` sql
+trimRight(input_string)
+```
+
+Alias: `rtrim(input_string)`.
+
+**Arguments**
+
+-   `input_string` — string to trim. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+A string without trailing common whitespaces.
+
+Type: `String`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT trimRight('     Hello, world!     ');
+```
+
+Result:
+
+``` text
+┌─trimRight('     Hello, world!     ')─┐
+│      Hello, world!                   │
+└──────────────────────────────────────┘
+```
+
+## trimBoth {#trimboth}
+
+Removes all consecutive occurrences of common whitespace (ASCII character 32) from both ends of a string. It does not remove other kinds of whitespace characters (tab, no-break space, etc.).
+
+**Syntax**
+
+``` sql
+trimBoth(input_string)
+```
+
+Alias: `trim(input_string)`.
+
+**Arguments**
+
+-   `input_string` — string to trim. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+A string without leading and trailing common whitespaces.
+
+Type: `String`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT trimBoth('     Hello, world!     ');
+```
+
+Result:
+
+``` text
+┌─trimBoth('     Hello, world!     ')─┐
+│ Hello, world!                       │
+└─────────────────────────────────────┘
+```
+
+## CRC32(s) {#crc32}
+
+Returns the CRC32 checksum of a string, using CRC-32-IEEE 802.3 polynomial and initial value `0xffffffff` (zlib implementation).
+
+The result type is UInt32.
+
+## CRC32IEEE(s) {#crc32ieee}
+
+Returns the CRC32 checksum of a string, using CRC-32-IEEE 802.3 polynomial.
+
+The result type is UInt32.
+
+## CRC64(s) {#crc64}
+
+Returns the CRC64 checksum of a string, using CRC-64-ECMA polynomial.
+
+The result type is UInt64.
+
+## normalizeQuery {#normalized-query}
+
+Replaces literals, sequences of literals and complex aliases with placeholders.
+
+**Syntax**
+
+``` sql
+normalizeQuery(x)
+```
+
+**Arguments**
+
+-   `x` — Sequence of characters. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Sequence of characters with placeholders.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT normalizeQuery('[1, 2, 3, x]') AS query;
+```
+
+Result:
+
+``` text
+┌─query────┐
+│ [?.., x] │
+└──────────┘
+```
+
+## normalizedQueryHash {#normalized-query-hash}
+
+Returns identical 64bit hash values without the values of literals for similar queries. It helps to analyze query log.
+
+**Syntax**
+
+``` sql
+normalizedQueryHash(x)
+```
+
+**Arguments**
+
+-   `x` — Sequence of characters. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Hash value.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT normalizedQueryHash('SELECT 1 AS `xyz`') != normalizedQueryHash('SELECT 1 AS `abc`') AS res;
+```
+
+Result:
+
+``` text
+┌─res─┐
+│   1 │
+└─────┘
+```
+
+## normalizeUTF8NFC {#normalizeutf8nfc}
+
+Converts a string to [NFC normalized form](https://en.wikipedia.org/wiki/Unicode_equivalence#Normal_forms), assuming the string contains a set of bytes that make up a UTF-8 encoded text.
+
+**Syntax**
+
+``` sql
+normalizeUTF8NFC(words)
+```
+
+**Arguments**
+
+-   `words` — Input string that contains UTF-8 encoded text. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   String transformed to NFC normalization form.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT length('â'), normalizeUTF8NFC('â') AS nfc, length(nfc) AS nfc_len;
+```
+
+Result:
+
+``` text
+┌─length('â')─┬─nfc─┬─nfc_len─┐
+│           2 │ â   │       2 │
+└─────────────┴─────┴─────────┘
+```
+
+## normalizeUTF8NFD {#normalizeutf8nfd}
+
+Converts a string to [NFD normalized form](https://en.wikipedia.org/wiki/Unicode_equivalence#Normal_forms), assuming the string contains a set of bytes that make up a UTF-8 encoded text.
+
+**Syntax**
+
+``` sql
+normalizeUTF8NFD(words)
+```
+
+**Arguments**
+
+-   `words` — Input string that contains UTF-8 encoded text. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   String transformed to NFD normalization form.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT length('â'), normalizeUTF8NFD('â') AS nfd, length(nfd) AS nfd_len;
+```
+
+Result:
+
+``` text
+┌─length('â')─┬─nfd─┬─nfd_len─┐
+│           2 │ â   │       3 │
+└─────────────┴─────┴─────────┘
+```
+
+## normalizeUTF8NFKC {#normalizeutf8nfkc}
+
+Converts a string to [NFKC normalized form](https://en.wikipedia.org/wiki/Unicode_equivalence#Normal_forms), assuming the string contains a set of bytes that make up a UTF-8 encoded text.
+
+**Syntax**
+
+``` sql
+normalizeUTF8NFKC(words)
+```
+
+**Arguments**
+
+-   `words` — Input string that contains UTF-8 encoded text. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   String transformed to NFKC normalization form.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT length('â'), normalizeUTF8NFKC('â') AS nfkc, length(nfkc) AS nfkc_len;
+```
+
+Result:
+
+``` text
+┌─length('â')─┬─nfkc─┬─nfkc_len─┐
+│           2 │ â    │        2 │
+└─────────────┴──────┴──────────┘
+```
+
+## normalizeUTF8NFKD {#normalizeutf8nfkd}
+
+Converts a string to [NFKD normalized form](https://en.wikipedia.org/wiki/Unicode_equivalence#Normal_forms), assuming the string contains a set of bytes that make up a UTF-8 encoded text.
+
+**Syntax**
+
+``` sql
+normalizeUTF8NFKD(words)
+```
+
+**Arguments**
+
+-   `words` — Input string that contains UTF-8 encoded text. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   String transformed to NFKD normalization form.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT length('â'), normalizeUTF8NFKD('â') AS nfkd, length(nfkd) AS nfkd_len;
+```
+
+Result:
+
+``` text
+┌─length('â')─┬─nfkd─┬─nfkd_len─┐
+│           2 │ â    │        3 │
+└─────────────┴──────┴──────────┘
+```
+
+## encodeXMLComponent {#encode-xml-component}
+
+Escapes characters to place string into XML text node or attribute.
+
+The following five XML predefined entities will be replaced: `<`, `&`, `>`, `"`, `'`.
+
+**Syntax**
+
+``` sql
+encodeXMLComponent(x)
+```
+
+**Arguments**
+
+-   `x` — The sequence of characters. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   The sequence of characters with escape characters.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT encodeXMLComponent('Hello, "world"!');
+SELECT encodeXMLComponent('<123>');
+SELECT encodeXMLComponent('&clickhouse');
+SELECT encodeXMLComponent('\'foo\'');
+```
+
+Result:
+
+``` text
+Hello, &quot;world&quot;!
+&lt;123&gt;
+&amp;clickhouse
+&apos;foo&apos;
+```
+
+## decodeXMLComponent {#decode-xml-component}
+
+Replaces XML predefined entities with characters. Predefined entities are `&quot;` `&amp;` `&apos;` `&gt;` `&lt;`
+This function also replaces numeric character references with Unicode characters. Both decimal (like `&#10003;`) and hexadecimal (`&#x2713;`) forms are supported.
+
+**Syntax**
+
+``` sql
+decodeXMLComponent(x)
+```
+
+**Arguments**
+
+-   `x` — A sequence of characters. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   The sequence of characters after replacement.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT decodeXMLComponent('&apos;foo&apos;');
+SELECT decodeXMLComponent('&lt; &#x3A3; &gt;');
+```
+
+Result:
+
+``` text
+'foo'
+< Σ >
+```
+
+**See Also**
+
+-   [List of XML and HTML character entity references](https://en.wikipedia.org/wiki/List_of_XML_and_HTML_character_entity_references)
+
+
+
+## extractTextFromHTML {#extracttextfromhtml}
+
+A function to extract text from HTML or XHTML.
+It does not necessarily 100% conform to any of the HTML, XML or XHTML standards, but the implementation is reasonably accurate and it is fast. The rules are the following:
+
+1. Comments are skipped. Example: `<!-- test -->`. Comment must end with `-->`. Nested comments are not possible.
+Note: constructions like `<!-->` and `<!--->` are not valid comments in HTML but they are skipped by other rules.
+2. CDATA is pasted verbatim. Note: CDATA is XML/XHTML specific. But it is processed for "best-effort" approach.
+3. `script` and `style` elements are removed with all their content. Note: it is assumed that closing tag cannot appear inside content. For example, in JS string literal has to be escaped like `"<\/script>"`.
+Note: comments and CDATA are possible inside `script` or `style` - then closing tags are not searched inside CDATA. Example: `<script><![CDATA[</script>]]></script>`. But they are still searched inside comments. Sometimes it becomes complicated: `<script>var x = "<!--"; </script> var y = "-->"; alert(x + y);</script>`
+Note: `script` and `style` can be the names of XML namespaces - then they are not treated like usual `script` or `style` elements. Example: `<script:a>Hello</script:a>`.
+Note: whitespaces are possible after closing tag name: `</script >` but not before: `< / script>`.
+4. Other tags or tag-like elements are skipped without inner content. Example: `<a>.</a>`
+Note: it is expected that this HTML is illegal: `<a test=">"></a>`
+Note: it also skips something like tags: `<>`, `<!>`, etc.
+Note: tag without end is skipped to the end of input: `<hello   `
+5. HTML and XML entities are not decoded. They must be processed by separate function.
+6. Whitespaces in the text are collapsed or inserted by specific rules.
+    - Whitespaces at the beginning and at the end are removed.
+    - Consecutive whitespaces are collapsed.
+    - But if the text is separated by other elements and there is no whitespace, it is inserted.
+    - It may cause unnatural examples: `Hello<b>world</b>`, `Hello<!-- -->world` - there is no whitespace in HTML, but the function inserts it. Also consider: `Hello<p>world</p>`, `Hello<br>world`. This behavior is reasonable for data analysis, e.g. to convert HTML to a bag of words.
+7. Also note that correct handling of whitespaces requires the support of `<pre></pre>` and CSS `display` and `white-space` properties.
+
+**Syntax**
+
+``` sql
+extractTextFromHTML(x)
+```
+
+**Arguments**
+
+-   `x` — input text. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Extracted text.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+The first example contains several tags and a comment and also shows whitespace processing.
+The second example shows `CDATA` and `script` tag processing.
+In the third example text is extracted from the full HTML response received by the [url](../../sql-reference/table-functions/url.md) function.
+
+Query:
+
+``` sql
+SELECT extractTextFromHTML(' <p> A text <i>with</i><b>tags</b>. <!-- comments --> </p> ');
+SELECT extractTextFromHTML('<![CDATA[The content within <b>CDATA</b>]]> <script>alert("Script");</script>');
+SELECT extractTextFromHTML(html) FROM url('http://www.donothingfor2minutes.com/', RawBLOB, 'html String');
+```
+
+Result:
+
+``` text
+A text with tags .
+The content within <b>CDATA</b>
+Do Nothing for 2 Minutes 2:00 &nbsp;
+```
diff --git a/docs/en/reference/sql-reference/functions/string-replace-functions.md b/docs/en/reference/sql-reference/functions/string-replace-functions.md
new file mode 100644
index 00000000000..1df8bfd0c44
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/string-replace-functions.md
@@ -0,0 +1,95 @@
+---
+sidebar_position: 42
+sidebar_label: For Replacing in Strings
+---
+
+# Functions for Searching and Replacing in Strings {#functions-for-searching-and-replacing-in-strings}
+
+:::note    
+Functions for [searching](../../sql-reference/functions/string-search-functions.md) and [other manipulations with strings](../../sql-reference/functions/string-functions.md) are described separately.
+:::
+
+## replaceOne(haystack, pattern, replacement) {#replaceonehaystack-pattern-replacement}
+
+Replaces the first occurrence, if it exists, of the ‘pattern’ substring in ‘haystack’ with the ‘replacement’ substring.
+Hereafter, ‘pattern’ and ‘replacement’ must be constants.
+
+## replaceAll(haystack, pattern, replacement), replace(haystack, pattern, replacement) {#replaceallhaystack-pattern-replacement-replacehaystack-pattern-replacement}
+
+Replaces all occurrences of the ‘pattern’ substring in ‘haystack’ with the ‘replacement’ substring.
+
+## replaceRegexpOne(haystack, pattern, replacement) {#replaceregexponehaystack-pattern-replacement}
+
+Replacement using the ‘pattern’ regular expression. A re2 regular expression.
+Replaces only the first occurrence, if it exists.
+A pattern can be specified as ‘replacement’. This pattern can include substitutions `\0-\9`.
+The substitution `\0` includes the entire regular expression. Substitutions `\1-\9` correspond to the subpattern numbers.To use the `\` character in a template, escape it using `\`.
+Also keep in mind that a string literal requires an extra escape.
+
+Example 1. Converting the date to American format:
+
+``` sql
+SELECT DISTINCT
+    EventDate,
+    replaceRegexpOne(toString(EventDate), '(\\d{4})-(\\d{2})-(\\d{2})', '\\2/\\3/\\1') AS res
+FROM test.hits
+LIMIT 7
+FORMAT TabSeparated
+```
+
+``` text
+2014-03-17      03/17/2014
+2014-03-18      03/18/2014
+2014-03-19      03/19/2014
+2014-03-20      03/20/2014
+2014-03-21      03/21/2014
+2014-03-22      03/22/2014
+2014-03-23      03/23/2014
+```
+
+Example 2. Copying a string ten times:
+
+``` sql
+SELECT replaceRegexpOne('Hello, World!', '.*', '\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0') AS res
+```
+
+``` text
+┌─res────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World! │
+└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+## replaceRegexpAll(haystack, pattern, replacement) {#replaceregexpallhaystack-pattern-replacement}
+
+This does the same thing, but replaces all the occurrences. Example:
+
+``` sql
+SELECT replaceRegexpAll('Hello, World!', '.', '\\0\\0') AS res
+```
+
+``` text
+┌─res────────────────────────┐
+│ HHeelllloo,,  WWoorrlldd!! │
+└────────────────────────────┘
+```
+
+As an exception, if a regular expression worked on an empty substring, the replacement is not made more than once.
+Example:
+
+``` sql
+SELECT replaceRegexpAll('Hello, World!', '^', 'here: ') AS res
+```
+
+``` text
+┌─res─────────────────┐
+│ here: Hello, World! │
+└─────────────────────┘
+```
+
+## regexpQuoteMeta(s) {#regexpquotemetas}
+
+The function adds a backslash before some predefined characters in the string.
+Predefined characters: `\0`, `\\`, `|`, `(`, `)`, `^`, `$`, `.`, `[`, `]`, `?`, `*`, `+`, `{`, `:`, `-`.
+This implementation slightly differs from re2::RE2::QuoteMeta. It escapes zero byte as `\0` instead of `\x00` and it escapes only required characters.
+For more information, see the link: [RE2](https://github.com/google/re2/blob/master/re2/re2.cc#L473)
+
diff --git a/docs/en/reference/sql-reference/functions/string-search-functions.md b/docs/en/reference/sql-reference/functions/string-search-functions.md
new file mode 100644
index 00000000000..985d9f1e63a
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/string-search-functions.md
@@ -0,0 +1,819 @@
+---
+sidebar_position: 41
+sidebar_label: For Searching in Strings
+---
+
+# Functions for Searching in Strings {#functions-for-searching-strings}
+
+The search is case-sensitive by default in all these functions. There are separate variants for case insensitive search.
+
+:::note    
+Functions for [replacing](../../sql-reference/functions/string-replace-functions.md) and [other manipulations with strings](../../sql-reference/functions/string-functions.md) are described separately.
+:::
+
+## position(haystack, needle), locate(haystack, needle) {#position}
+
+Searches for the substring `needle` in the string `haystack`.
+
+Returns the position (in bytes) of the found substring in the string, starting from 1.
+
+For a case-insensitive search, use the function [positionCaseInsensitive](#positioncaseinsensitive).
+
+**Syntax**
+
+``` sql
+position(haystack, needle[, start_pos])
+```
+
+``` sql
+position(needle IN haystack)
+```
+
+Alias: `locate(haystack, needle[, start_pos])`.
+
+:::note    
+Syntax of `position(needle IN haystack)` provides SQL-compatibility, the function works the same way as to `position(haystack, needle)`.
+:::
+
+**Arguments**
+
+-   `haystack` — String, in which substring will to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `needle` — Substring to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `start_pos` – Position of the first character in the string to start search. [UInt](../../sql-reference/data-types/int-uint.md). Optional.
+
+**Returned values**
+
+-   Starting position in bytes (counting from 1), if substring was found.
+-   0, if the substring was not found.
+
+Type: `Integer`.
+
+**Examples**
+
+The phrase “Hello, world!” contains a set of bytes representing a single-byte encoded text. The function returns some expected result:
+
+Query:
+
+``` sql
+SELECT position('Hello, world!', '!');
+```
+
+Result:
+
+``` text
+┌─position('Hello, world!', '!')─┐
+│                             13 │
+└────────────────────────────────┘
+```
+
+``` sql
+SELECT
+    position('Hello, world!', 'o', 1),
+    position('Hello, world!', 'o', 7)
+```
+
+``` text
+┌─position('Hello, world!', 'o', 1)─┬─position('Hello, world!', 'o', 7)─┐
+│                                 5 │                                 9 │
+└───────────────────────────────────┴───────────────────────────────────┘
+```
+
+The same phrase in Russian contains characters which can’t be represented using a single byte. The function returns some unexpected result (use [positionUTF8](#positionutf8) function for multi-byte encoded text):
+
+Query:
+
+``` sql
+SELECT position('Привет, мир!', '!');
+```
+
+Result:
+
+``` text
+┌─position('Привет, мир!', '!')─┐
+│                            21 │
+└───────────────────────────────┘
+```
+
+**Examples for POSITION(needle IN haystack) syntax**
+
+Query:
+
+```sql
+SELECT 3 = position('c' IN 'abc');
+```
+
+Result:
+
+```text
+┌─equals(3, position('abc', 'c'))─┐
+│                               1 │
+└─────────────────────────────────┘
+```
+
+Query:
+
+```sql
+SELECT 6 = position('/' IN s) FROM (SELECT 'Hello/World' AS s);
+```
+
+Result:
+
+```text
+┌─equals(6, position(s, '/'))─┐
+│                           1 │
+└─────────────────────────────┘
+```
+
+## positionCaseInsensitive {#positioncaseinsensitive}
+
+The same as [position](#position) returns the position (in bytes) of the found substring in the string, starting from 1. Use the function for a case-insensitive search.
+
+Works under the assumption that the string contains a set of bytes representing a single-byte encoded text. If this assumption is not met and a character can’t be represented using a single byte, the function does not throw an exception and returns some unexpected result. If character can be represented using two bytes, it will use two bytes and so on.
+
+**Syntax**
+
+``` sql
+positionCaseInsensitive(haystack, needle[, start_pos])
+```
+
+**Arguments**
+
+-   `haystack` — String, in which substring will to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `needle` — Substring to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `start_pos` — Optional parameter, position of the first character in the string to start search. [UInt](../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Starting position in bytes (counting from 1), if substring was found.
+-   0, if the substring was not found.
+
+Type: `Integer`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT positionCaseInsensitive('Hello, world!', 'hello');
+```
+
+Result:
+
+``` text
+┌─positionCaseInsensitive('Hello, world!', 'hello')─┐
+│                                                 1 │
+└───────────────────────────────────────────────────┘
+```
+
+## positionUTF8 {#positionutf8}
+
+Returns the position (in Unicode points) of the found substring in the string, starting from 1.
+
+Works under the assumption that the string contains a set of bytes representing a UTF-8 encoded text. If this assumption is not met, the function does not throw an exception and returns some unexpected result. If character can be represented using two Unicode points, it will use two and so on.
+
+For a case-insensitive search, use the function [positionCaseInsensitiveUTF8](#positioncaseinsensitiveutf8).
+
+**Syntax**
+
+``` sql
+positionUTF8(haystack, needle[, start_pos])
+```
+
+**Arguments**
+
+-   `haystack` — String, in which substring will to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `needle` — Substring to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `start_pos` — Optional parameter, position of the first character in the string to start search. [UInt](../../sql-reference/data-types/int-uint.md)
+
+**Returned values**
+
+-   Starting position in Unicode points (counting from 1), if substring was found.
+-   0, if the substring was not found.
+
+Type: `Integer`.
+
+**Examples**
+
+The phrase “Hello, world!” in Russian contains a set of Unicode points representing a single-point encoded text. The function returns some expected result:
+
+Query:
+
+``` sql
+SELECT positionUTF8('Привет, мир!', '!');
+```
+
+Result:
+
+``` text
+┌─positionUTF8('Привет, мир!', '!')─┐
+│                                12 │
+└───────────────────────────────────┘
+```
+
+The phrase “Salut, étudiante!”, where character `é` can be represented using a one point (`U+00E9`) or two points (`U+0065U+0301`) the function can be returned some unexpected result:
+
+Query for the letter `é`, which is represented one Unicode point `U+00E9`:
+
+``` sql
+SELECT positionUTF8('Salut, étudiante!', '!');
+```
+
+Result:
+
+``` text
+┌─positionUTF8('Salut, étudiante!', '!')─┐
+│                                     17 │
+└────────────────────────────────────────┘
+```
+
+Query for the letter `é`, which is represented two Unicode points `U+0065U+0301`:
+
+``` sql
+SELECT positionUTF8('Salut, étudiante!', '!');
+```
+
+Result:
+
+``` text
+┌─positionUTF8('Salut, étudiante!', '!')─┐
+│                                     18 │
+└────────────────────────────────────────┘
+```
+
+## positionCaseInsensitiveUTF8 {#positioncaseinsensitiveutf8}
+
+The same as [positionUTF8](#positionutf8), but is case-insensitive. Returns the position (in Unicode points) of the found substring in the string, starting from 1.
+
+Works under the assumption that the string contains a set of bytes representing a UTF-8 encoded text. If this assumption is not met, the function does not throw an exception and returns some unexpected result. If character can be represented using two Unicode points, it will use two and so on.
+
+**Syntax**
+
+``` sql
+positionCaseInsensitiveUTF8(haystack, needle[, start_pos])
+```
+
+**Arguments**
+
+-   `haystack` — String, in which substring will to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `needle` — Substring to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `start_pos` — Optional parameter, position of the first character in the string to start search. [UInt](../../sql-reference/data-types/int-uint.md)
+
+**Returned value**
+
+-   Starting position in Unicode points (counting from 1), if substring was found.
+-   0, if the substring was not found.
+
+Type: `Integer`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT positionCaseInsensitiveUTF8('Привет, мир!', 'Мир');
+```
+
+Result:
+
+``` text
+┌─positionCaseInsensitiveUTF8('Привет, мир!', 'Мир')─┐
+│                                                  9 │
+└────────────────────────────────────────────────────┘
+```
+
+## multiSearchAllPositions {#multisearchallpositions}
+
+The same as [position](../../sql-reference/functions/string-search-functions.md#position) but returns `Array` of positions (in bytes) of the found corresponding substrings in the string. Positions are indexed starting from 1.
+
+The search is performed on sequences of bytes without respect to string encoding and collation.
+
+-   For case-insensitive ASCII search, use the function `multiSearchAllPositionsCaseInsensitive`.
+-   For search in UTF-8, use the function [multiSearchAllPositionsUTF8](#multiSearchAllPositionsUTF8).
+-   For case-insensitive UTF-8 search, use the function multiSearchAllPositionsCaseInsensitiveUTF8.
+
+**Syntax**
+
+``` sql
+multiSearchAllPositions(haystack, [needle1, needle2, ..., needlen])
+```
+
+**Arguments**
+
+-   `haystack` — String, in which substring will to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `needle` — Substring to be searched. [String](../../sql-reference/syntax.md#syntax-string-literal).
+
+**Returned values**
+
+-   Array of starting positions in bytes (counting from 1), if the corresponding substring was found and 0 if not found.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT multiSearchAllPositions('Hello, World!', ['hello', '!', 'world']);
+```
+
+Result:
+
+``` text
+┌─multiSearchAllPositions('Hello, World!', ['hello', '!', 'world'])─┐
+│ [0,13,0]                                                          │
+└───────────────────────────────────────────────────────────────────┘
+```
+
+## multiSearchAllPositionsUTF8 {#multiSearchAllPositionsUTF8}
+
+See `multiSearchAllPositions`.
+
+## multiSearchFirstPosition(haystack, \[needle<sub>1</sub>, needle<sub>2</sub>, …, needle<sub>n</sub>\]) {#multisearchfirstposition}
+
+The same as `position` but returns the leftmost offset of the string `haystack` that is matched to some of the needles.
+
+For a case-insensitive search or/and in UTF-8 format use functions `multiSearchFirstPositionCaseInsensitive, multiSearchFirstPositionUTF8, multiSearchFirstPositionCaseInsensitiveUTF8`.
+
+## multiSearchFirstIndex(haystack, \[needle<sub>1</sub>, needle<sub>2</sub>, …, needle<sub>n</sub>\]) {#multisearchfirstindexhaystack-needle1-needle2-needlen}
+
+Returns the index `i` (starting from 1) of the leftmost found needle<sub>i</sub> in the string `haystack` and 0 otherwise.
+
+For a case-insensitive search or/and in UTF-8 format use functions `multiSearchFirstIndexCaseInsensitive, multiSearchFirstIndexUTF8, multiSearchFirstIndexCaseInsensitiveUTF8`.
+
+## multiSearchAny(haystack, \[needle<sub>1</sub>, needle<sub>2</sub>, …, needle<sub>n</sub>\]) {#function-multisearchany}
+
+Returns 1, if at least one string needle<sub>i</sub> matches the string `haystack` and 0 otherwise.
+
+For a case-insensitive search or/and in UTF-8 format use functions `multiSearchAnyCaseInsensitive, multiSearchAnyUTF8, multiSearchAnyCaseInsensitiveUTF8`.
+
+:::note    
+In all `multiSearch*` functions the number of needles should be less than 2<sup>8</sup> because of implementation specification.
+:::
+
+## match(haystack, pattern) {#matchhaystack-pattern}
+
+Checks whether the string matches the `pattern` regular expression. A `re2` regular expression. The [syntax](https://github.com/google/re2/wiki/Syntax) of the `re2` regular expressions is more limited than the syntax of the Perl regular expressions.
+
+Returns 0 if it does not match, or 1 if it matches.
+
+The regular expression works with the string as if it is a set of bytes. The regular expression can’t contain null bytes.
+For patterns to search for substrings in a string, it is better to use LIKE or ‘position’, since they work much faster.
+
+## multiMatchAny(haystack, \[pattern<sub>1</sub>, pattern<sub>2</sub>, …, pattern<sub>n</sub>\]) {#multimatchanyhaystack-pattern1-pattern2-patternn}
+
+The same as `match`, but returns 0 if none of the regular expressions are matched and 1 if any of the patterns matches. It uses [hyperscan](https://github.com/intel/hyperscan) library. For patterns to search substrings in a string, it is better to use `multiSearchAny` since it works much faster.
+
+:::note    
+The length of any of the `haystack` string must be less than 2<sup>32</sup> bytes otherwise the exception is thrown. This restriction takes place because of hyperscan API.
+:::
+
+## multiMatchAnyIndex(haystack, \[pattern<sub>1</sub>, pattern<sub>2</sub>, …, pattern<sub>n</sub>\]) {#multimatchanyindexhaystack-pattern1-pattern2-patternn}
+
+The same as `multiMatchAny`, but returns any index that matches the haystack.
+
+## multiMatchAllIndices(haystack, \[pattern<sub>1</sub>, pattern<sub>2</sub>, …, pattern<sub>n</sub>\]) {#multimatchallindiceshaystack-pattern1-pattern2-patternn}
+
+The same as `multiMatchAny`, but returns the array of all indicies that match the haystack in any order.
+
+## multiFuzzyMatchAny(haystack, distance, \[pattern<sub>1</sub>, pattern<sub>2</sub>, …, pattern<sub>n</sub>\]) {#multifuzzymatchanyhaystack-distance-pattern1-pattern2-patternn}
+
+The same as `multiMatchAny`, but returns 1 if any pattern matches the haystack within a constant [edit distance](https://en.wikipedia.org/wiki/Edit_distance). This function relies on the experimental feature of [hyperscan](https://intel.github.io/hyperscan/dev-reference/compilation.html#approximate-matching) library, and can be slow for some corner cases. The performance depends on the edit distance value and patterns used, but it's always more expensive compared to a non-fuzzy variants.
+
+## multiFuzzyMatchAnyIndex(haystack, distance, \[pattern<sub>1</sub>, pattern<sub>2</sub>, …, pattern<sub>n</sub>\]) {#multifuzzymatchanyindexhaystack-distance-pattern1-pattern2-patternn}
+
+The same as `multiFuzzyMatchAny`, but returns any index that matches the haystack within a constant edit distance.
+
+## multiFuzzyMatchAllIndices(haystack, distance, \[pattern<sub>1</sub>, pattern<sub>2</sub>, …, pattern<sub>n</sub>\]) {#multifuzzymatchallindiceshaystack-distance-pattern1-pattern2-patternn}
+
+The same as `multiFuzzyMatchAny`, but returns the array of all indices in any order that match the haystack within a constant edit distance.
+
+:::note    
+`multiFuzzyMatch*` functions do not support UTF-8 regular expressions, and such expressions are treated as bytes because of hyperscan restriction.
+:::
+
+:::note    
+To turn off all functions that use hyperscan, use setting `SET allow_hyperscan = 0;`.
+:::
+
+## extract(haystack, pattern) {#extracthaystack-pattern}
+
+Extracts a fragment of a string using a regular expression. If ‘haystack’ does not match the ‘pattern’ regex, an empty string is returned. If the regex does not contain subpatterns, it takes the fragment that matches the entire regex. Otherwise, it takes the fragment that matches the first subpattern.
+
+## extractAll(haystack, pattern) {#extractallhaystack-pattern}
+
+Extracts all the fragments of a string using a regular expression. If ‘haystack’ does not match the ‘pattern’ regex, an empty string is returned. Returns an array of strings consisting of all matches to the regex. In general, the behavior is the same as the ‘extract’ function (it takes the first subpattern, or the entire expression if there isn’t a subpattern).
+
+## extractAllGroupsHorizontal {#extractallgroups-horizontal}
+
+Matches all groups of the `haystack` string using the `pattern` regular expression. Returns an array of arrays, where the first array includes all fragments matching the first group, the second array - matching the second group, etc.
+
+:::note    
+`extractAllGroupsHorizontal` function is slower than [extractAllGroupsVertical](#extractallgroups-vertical).
+:::
+
+**Syntax**
+
+``` sql
+extractAllGroupsHorizontal(haystack, pattern)
+```
+
+**Arguments**
+
+-   `haystack` — Input string. Type: [String](../../sql-reference/data-types/string.md).
+-   `pattern` — Regular expression with [re2 syntax](https://github.com/google/re2/wiki/Syntax). Must contain groups, each group enclosed in parentheses. If `pattern` contains no groups, an exception is thrown. Type: [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Type: [Array](../../sql-reference/data-types/array.md).
+
+If `haystack` does not match the `pattern` regex, an array of empty arrays is returned.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT extractAllGroupsHorizontal('abc=111, def=222, ghi=333', '("[^"]+"|\\w+)=("[^"]+"|\\w+)');
+```
+
+Result:
+
+``` text
+┌─extractAllGroupsHorizontal('abc=111, def=222, ghi=333', '("[^"]+"|\\w+)=("[^"]+"|\\w+)')─┐
+│ [['abc','def','ghi'],['111','222','333']]                                                │
+└──────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [extractAllGroupsVertical](#extractallgroups-vertical)
+
+## extractAllGroupsVertical {#extractallgroups-vertical}
+
+Matches all groups of the `haystack` string using the `pattern` regular expression. Returns an array of arrays, where each array includes matching fragments from every group. Fragments are grouped in order of appearance in the `haystack`.
+
+**Syntax**
+
+``` sql
+extractAllGroupsVertical(haystack, pattern)
+```
+
+**Arguments**
+
+-   `haystack` — Input string. Type: [String](../../sql-reference/data-types/string.md).
+-   `pattern` — Regular expression with [re2 syntax](https://github.com/google/re2/wiki/Syntax). Must contain groups, each group enclosed in parentheses. If `pattern` contains no groups, an exception is thrown. Type: [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Type: [Array](../../sql-reference/data-types/array.md).
+
+If `haystack` does not match the `pattern` regex, an empty array is returned.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT extractAllGroupsVertical('abc=111, def=222, ghi=333', '("[^"]+"|\\w+)=("[^"]+"|\\w+)');
+```
+
+Result:
+
+``` text
+┌─extractAllGroupsVertical('abc=111, def=222, ghi=333', '("[^"]+"|\\w+)=("[^"]+"|\\w+)')─┐
+│ [['abc','111'],['def','222'],['ghi','333']]                                            │
+└────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [extractAllGroupsHorizontal](#extractallgroups-horizontal)
+
+## like(haystack, pattern), haystack LIKE pattern operator {#function-like}
+
+Checks whether a string matches a simple regular expression.
+The regular expression can contain the metasymbols `%` and `_`.
+
+`%` indicates any quantity of any bytes (including zero characters).
+
+`_` indicates any one byte.
+
+Use the backslash (`\`) for escaping metasymbols. See the note on escaping in the description of the ‘match’ function.
+
+For regular expressions like `%needle%`, the code is more optimal and works as fast as the `position` function.
+For other regular expressions, the code is the same as for the ‘match’ function.
+
+## notLike(haystack, pattern), haystack NOT LIKE pattern operator {#function-notlike}
+
+The same thing as ‘like’, but negative.
+
+## ilike {#ilike}
+
+Case insensitive variant of [like](https://clickhouse.com/docs/en/sql-reference/functions/string-search-functions/#function-like) function. You can use `ILIKE` operator instead of the `ilike` function.
+
+**Syntax**
+
+``` sql
+ilike(haystack, pattern)
+```
+
+**Arguments**
+
+-   `haystack` — Input string. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `pattern` — If `pattern` does not contain percent signs or underscores, then the `pattern` only represents the string itself. An underscore (`_`) in `pattern` stands for (matches) any single character. A percent sign (`%`) matches any sequence of zero or more characters.
+
+Some `pattern` examples:
+
+``` text
+'abc' ILIKE 'abc'    true
+'abc' ILIKE 'a%'     true
+'abc' ILIKE '_b_'    true
+'abc' ILIKE 'c'      false
+```
+
+**Returned values**
+
+-   True, if the string matches `pattern`.
+-   False, if the string does not match `pattern`.
+
+**Example**
+
+Input table:
+
+``` text
+┌─id─┬─name─────┬─days─┐
+│  1 │ January  │   31 │
+│  2 │ February │   29 │
+│  3 │ March    │   31 │
+│  4 │ April    │   30 │
+└────┴──────────┴──────┘
+```
+
+Query:
+
+``` sql
+SELECT * FROM Months WHERE ilike(name, '%j%');
+```
+
+Result:
+
+``` text
+┌─id─┬─name────┬─days─┐
+│  1 │ January │   31 │
+└────┴─────────┴──────┘
+```
+
+**See Also**
+
+-   [like](https://clickhouse.com/docs/en/sql-reference/functions/string-search-functions/#function-like) <!--hide-->
+
+## ngramDistance(haystack, needle) {#ngramdistancehaystack-needle}
+
+Calculates the 4-gram distance between `haystack` and `needle`: counts the symmetric difference between two multisets of 4-grams and normalizes it by the sum of their cardinalities. Returns float number from 0 to 1 – the closer to zero, the more strings are similar to each other. If the constant `needle` or `haystack` is more than 32Kb, throws an exception. If some of the non-constant `haystack` or `needle` strings are more than 32Kb, the distance is always one.
+
+For case-insensitive search or/and in UTF-8 format use functions `ngramDistanceCaseInsensitive, ngramDistanceUTF8, ngramDistanceCaseInsensitiveUTF8`.
+
+## ngramSearch(haystack, needle) {#ngramsearchhaystack-needle}
+
+Same as `ngramDistance` but calculates the non-symmetric difference between `needle` and `haystack` – the number of n-grams from needle minus the common number of n-grams normalized by the number of `needle` n-grams. The closer to one, the more likely `needle` is in the `haystack`. Can be useful for fuzzy string search.
+
+For case-insensitive search or/and in UTF-8 format use functions `ngramSearchCaseInsensitive, ngramSearchUTF8, ngramSearchCaseInsensitiveUTF8`.
+
+:::note    
+For UTF-8 case we use 3-gram distance. All these are not perfectly fair n-gram distances. We use 2-byte hashes to hash n-grams and then calculate the (non-)symmetric difference between these hash tables – collisions may occur. With UTF-8 case-insensitive format we do not use fair `tolower` function – we zero the 5-th bit (starting from zero) of each codepoint byte and first bit of zeroth byte if bytes more than one – this works for Latin and mostly for all Cyrillic letters.
+:::
+
+## countSubstrings {#countSubstrings}
+
+Returns the number of substring occurrences.
+
+For a case-insensitive search, use [countSubstringsCaseInsensitive](../../sql-reference/functions/string-search-functions.md#countSubstringsCaseInsensitive) or [countSubstringsCaseInsensitiveUTF8](../../sql-reference/functions/string-search-functions.md#countSubstringsCaseInsensitiveUTF8) functions.
+
+**Syntax**
+
+``` sql
+countSubstrings(haystack, needle[, start_pos])
+```
+
+**Arguments**
+
+-   `haystack` — The string to search in. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `needle` — The substring to search for. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `start_pos` – Position of the first character in the string to start search. Optional. [UInt](../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Number of occurrences.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT countSubstrings('foobar.com', '.');
+```
+
+Result:
+
+``` text
+┌─countSubstrings('foobar.com', '.')─┐
+│                                  1 │
+└────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT countSubstrings('aaaa', 'aa');
+```
+
+Result:
+
+``` text
+┌─countSubstrings('aaaa', 'aa')─┐
+│                             2 │
+└───────────────────────────────┘
+```
+
+Query:
+
+```sql
+SELECT countSubstrings('abc___abc', 'abc', 4);
+```
+
+Result:
+
+``` text
+┌─countSubstrings('abc___abc', 'abc', 4)─┐
+│                                      1 │
+└────────────────────────────────────────┘
+```
+
+## countSubstringsCaseInsensitive {#countSubstringsCaseInsensitive}
+
+Returns the number of substring occurrences case-insensitive.
+
+**Syntax**
+
+``` sql
+countSubstringsCaseInsensitive(haystack, needle[, start_pos])
+```
+
+**Arguments**
+
+-   `haystack` — The string to search in. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `needle` — The substring to search for. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `start_pos` — Position of the first character in the string to start search. Optional. [UInt](../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Number of occurrences.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT countSubstringsCaseInsensitive('aba', 'B');
+```
+
+Result:
+
+``` text
+┌─countSubstringsCaseInsensitive('aba', 'B')─┐
+│                                          1 │
+└────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT countSubstringsCaseInsensitive('foobar.com', 'CoM');
+```
+
+Result:
+
+``` text
+┌─countSubstringsCaseInsensitive('foobar.com', 'CoM')─┐
+│                                                   1 │
+└─────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT countSubstringsCaseInsensitive('abC___abC', 'aBc', 2);
+```
+
+Result:
+
+``` text
+┌─countSubstringsCaseInsensitive('abC___abC', 'aBc', 2)─┐
+│                                                     1 │
+└───────────────────────────────────────────────────────┘
+```
+
+## countSubstringsCaseInsensitiveUTF8 {#countSubstringsCaseInsensitiveUTF8}
+
+Returns the number of substring occurrences in `UTF-8` case-insensitive.
+
+**Syntax**
+
+``` sql
+SELECT countSubstringsCaseInsensitiveUTF8(haystack, needle[, start_pos])
+```
+
+**Arguments**
+
+-   `haystack` — The string to search in. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `needle` — The substring to search for. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `start_pos` — Position of the first character in the string to start search. Optional. [UInt](../../sql-reference/data-types/int-uint.md).
+
+**Returned values**
+
+-   Number of occurrences.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT countSubstringsCaseInsensitiveUTF8('абв', 'A');
+```
+
+Result:
+
+``` text
+┌─countSubstringsCaseInsensitiveUTF8('абв', 'A')─┐
+│                                              1 │
+└────────────────────────────────────────────────┘
+```
+
+Query:
+
+```sql
+SELECT countSubstringsCaseInsensitiveUTF8('аБв__АбВ__абв', 'Абв');
+```
+
+Result:
+
+``` text
+┌─countSubstringsCaseInsensitiveUTF8('аБв__АбВ__абв', 'Абв')─┐
+│                                                          3 │
+└────────────────────────────────────────────────────────────┘
+```
+
+## countMatches(haystack, pattern) {#countmatcheshaystack-pattern}
+
+Returns the number of regular expression matches for a `pattern` in a `haystack`.
+
+**Syntax**
+
+``` sql
+countMatches(haystack, pattern)
+```
+
+**Arguments**
+
+-   `haystack` — The string to search in. [String](../../sql-reference/syntax.md#syntax-string-literal).
+-   `pattern` — The regular expression with [re2 syntax](https://github.com/google/re2/wiki/Syntax). [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   The number of matches.
+
+Type: [UInt64](../../sql-reference/data-types/int-uint.md).
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT countMatches('foobar.com', 'o+');
+```
+
+Result:
+
+``` text
+┌─countMatches('foobar.com', 'o+')─┐
+│                                2 │
+└──────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT countMatches('aaaa', 'aa');
+```
+
+Result:
+
+``` text
+┌─countMatches('aaaa', 'aa')────┐
+│                             2 │
+└───────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/time-window-functions.md b/docs/en/reference/sql-reference/functions/time-window-functions.md
new file mode 100644
index 00000000000..b45866cf931
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/time-window-functions.md
@@ -0,0 +1,112 @@
+---
+sidebar_position: 68
+sidebar_label: Time Window
+---
+
+# Time Window Functions {#time-window-functions}
+
+Time window functions return the inclusive lower and exclusive upper bound of the corresponding window. The functions for working with WindowView are listed below:
+
+## tumble {#time-window-functions-tumble}
+
+A tumbling time window assigns records to non-overlapping, continuous windows with a fixed duration (`interval`). 
+
+``` sql
+tumble(time_attr, interval [, timezone])
+```
+
+**Arguments**
+- `time_attr` - Date and time. [DateTime](../../sql-reference/data-types/datetime.md) data type.
+- `interval` - Window interval in [Interval](../../sql-reference/data-types/special-data-types/interval.md) data type.
+- `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) (optional). 
+
+**Returned values**
+
+- The inclusive lower and exclusive upper bound of the corresponding tumbling window.
+
+Type: `Tuple(DateTime, DateTime)`
+
+**Example**
+
+Query:
+
+``` sql
+SELECT tumble(now(), toIntervalDay('1'))
+```
+
+Result:
+
+``` text
+┌─tumble(now(), toIntervalDay('1'))─────────────┐
+│ ['2020-01-01 00:00:00','2020-01-02 00:00:00'] │
+└───────────────────────────────────────────────┘
+```
+
+## hop {#time-window-functions-hop}
+
+A hopping time window has a fixed duration (`window_interval`) and hops by a specified hop interval (`hop_interval`). If the `hop_interval` is smaller than the `window_interval`, hopping windows are overlapping. Thus, records can be assigned to multiple windows. 
+
+``` sql
+hop(time_attr, hop_interval, window_interval [, timezone])
+```
+
+**Arguments**
+
+- `time_attr` - Date and time. [DateTime](../../sql-reference/data-types/datetime.md) data type.
+- `hop_interval` - Hop interval in [Interval](../../sql-reference/data-types/special-data-types/interval.md) data type. Should be a positive number.
+- `window_interval` - Window interval in [Interval](../../sql-reference/data-types/special-data-types/interval.md) data type. Should be a positive number.
+- `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) (optional). 
+
+**Returned values**
+
+- The inclusive lower and exclusive upper bound of the corresponding hopping window. Since one record can be assigned to multiple hop windows, the function only returns the bound of the **first** window when hop function is used **without** `WINDOW VIEW`.
+
+Type: `Tuple(DateTime, DateTime)`
+
+**Example**
+
+Query:
+
+``` sql
+SELECT hop(now(), INTERVAL '1' SECOND, INTERVAL '2' SECOND)
+```
+
+Result:
+
+``` text
+┌─hop(now(), toIntervalSecond('1'), toIntervalSecond('2'))──┐
+│ ('2020-01-14 16:58:22','2020-01-14 16:58:24')             │
+└───────────────────────────────────────────────────────────┘
+```
+
+## tumbleStart {#time-window-functions-tumblestart}
+
+Returns the inclusive lower bound of the corresponding tumbling window.
+
+``` sql
+tumbleStart(time_attr, interval [, timezone]);
+```
+
+## tumbleEnd {#time-window-functions-tumbleend}
+
+Returns the exclusive upper bound of the corresponding tumbling window.
+
+``` sql
+tumbleEnd(time_attr, interval [, timezone]);
+```
+
+## hopStart {#time-window-functions-hopstart}
+
+Returns the inclusive lower bound of the corresponding hopping window.
+
+``` sql
+hopStart(time_attr, hop_interval, window_interval [, timezone]);
+```
+
+## hopEnd {#time-window-functions-hopend}
+
+Returns the exclusive upper bound of the corresponding hopping window.
+
+``` sql
+hopEnd(time_attr, hop_interval, window_interval [, timezone]);
+```
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/functions/tuple-functions.md b/docs/en/reference/sql-reference/functions/tuple-functions.md
new file mode 100644
index 00000000000..cfce02f4d31
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/tuple-functions.md
@@ -0,0 +1,1060 @@
+---
+sidebar_position: 66
+sidebar_label: Tuples
+---
+
+# Functions for Working with Tuples {#tuple-functions}
+
+## tuple {#tuple}
+
+A function that allows grouping multiple columns.
+For columns with the types T1, T2, …, it returns a Tuple(T1, T2, …) type tuple containing these columns. There is no cost to execute the function.
+Tuples are normally used as intermediate values for an argument of IN operators, or for creating a list of formal parameters of lambda functions. Tuples can’t be written to a table.
+
+The function implements the operator `(x, y, …)`.
+
+**Syntax**
+
+``` sql
+tuple(x, y, …)
+```
+
+## tupleElement {#tupleelement}
+
+A function that allows getting a column from a tuple.
+‘N’ is the column index, starting from 1. ‘N’ must be a constant. ‘N’ must be a strict postive integer no greater than the size of the tuple.
+There is no cost to execute the function.
+
+The function implements the operator `x.N`.
+
+**Syntax**
+
+``` sql
+tupleElement(tuple, n)
+```
+
+## untuple {#untuple}
+
+Performs syntactic substitution of [tuple](../../sql-reference/data-types/tuple.md#tuplet1-t2) elements in the call location.
+
+**Syntax**
+
+``` sql
+untuple(x)
+```
+
+You can use the `EXCEPT` expression to skip columns as a result of the query.
+
+**Arguments**
+
+-   `x` — A `tuple` function, column, or tuple of elements. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   None.
+
+**Examples**
+
+Input table:
+
+``` text
+┌─key─┬─v1─┬─v2─┬─v3─┬─v4─┬─v5─┬─v6────────┐
+│   1 │ 10 │ 20 │ 40 │ 30 │ 15 │ (33,'ab') │
+│   2 │ 25 │ 65 │ 70 │ 40 │  6 │ (44,'cd') │
+│   3 │ 57 │ 30 │ 20 │ 10 │  5 │ (55,'ef') │
+│   4 │ 55 │ 12 │  7 │ 80 │ 90 │ (66,'gh') │
+│   5 │ 30 │ 50 │ 70 │ 25 │ 55 │ (77,'kl') │
+└─────┴────┴────┴────┴────┴────┴───────────┘
+```
+
+Example of using a `Tuple`-type column as the `untuple` function parameter:
+
+Query:
+
+``` sql
+SELECT untuple(v6) FROM kv;
+```
+
+Result:
+
+``` text
+┌─_ut_1─┬─_ut_2─┐
+│    33 │ ab    │
+│    44 │ cd    │
+│    55 │ ef    │
+│    66 │ gh    │
+│    77 │ kl    │
+└───────┴───────┘
+```
+
+Note: the names are implementation specific and are subject to change. You should not assume specific names of the columns after application of the `untuple`.
+
+Example of using an `EXCEPT` expression:
+
+Query:
+
+``` sql
+SELECT untuple((* EXCEPT (v2, v3),)) FROM kv;
+```
+
+Result:
+
+``` text
+┌─key─┬─v1─┬─v4─┬─v5─┬─v6────────┐
+│   1 │ 10 │ 30 │ 15 │ (33,'ab') │
+│   2 │ 25 │ 40 │  6 │ (44,'cd') │
+│   3 │ 57 │ 10 │  5 │ (55,'ef') │
+│   4 │ 55 │ 80 │ 90 │ (66,'gh') │
+│   5 │ 30 │ 25 │ 55 │ (77,'kl') │
+└─────┴────┴────┴────┴───────────┘
+```
+
+**See Also**
+
+-   [Tuple](../../sql-reference/data-types/tuple.md)
+
+## tupleHammingDistance {#tuplehammingdistance}
+
+Returns the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) between two tuples of the same size.
+
+**Syntax**
+
+``` sql
+tupleHammingDistance(tuple1, tuple2)
+```
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple2` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+Tuples should have the same type of the elements.
+
+**Returned value**
+
+-   The Hamming distance.
+
+Type: The result type is calculed the same way it is for [Arithmetic functions](../../sql-reference/functions/arithmetic-functions.md), based on the number of elements in the input tuples.
+
+``` sql
+SELECT
+    toTypeName(tupleHammingDistance(tuple(0), tuple(0))) AS t1,
+    toTypeName(tupleHammingDistance((0, 0), (0, 0))) AS t2,
+    toTypeName(tupleHammingDistance((0, 0, 0), (0, 0, 0))) AS t3,
+    toTypeName(tupleHammingDistance((0, 0, 0, 0), (0, 0, 0, 0))) AS t4,
+    toTypeName(tupleHammingDistance((0, 0, 0, 0, 0), (0, 0, 0, 0, 0))) AS t5
+```
+
+``` text
+┌─t1────┬─t2─────┬─t3─────┬─t4─────┬─t5─────┐
+│ UInt8 │ UInt16 │ UInt32 │ UInt64 │ UInt64 │
+└───────┴────────┴────────┴────────┴────────┘
+```
+
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT tupleHammingDistance((1, 2, 3), (3, 2, 1)) AS HammingDistance;
+```
+
+Result:
+
+``` text
+┌─HammingDistance─┐
+│               2 │
+└─────────────────┘
+```
+
+Can be used with [MinHash](../../sql-reference/functions/hash-functions.md#ngramminhash) functions for detection of semi-duplicate strings:
+
+``` sql
+SELECT tupleHammingDistance(wordShingleMinHash(string), wordShingleMinHashCaseInsensitive(string)) as HammingDistance FROM (SELECT 'ClickHouse is a column-oriented database management system for online analytical processing of queries.' AS string);
+```
+
+Result:
+
+``` text
+┌─HammingDistance─┐
+│               2 │
+└─────────────────┘
+```
+
+## tupleToNameValuePairs {#tupletonamevaluepairs}
+
+Turns a named tuple into an array of (name, value) pairs. For a `Tuple(a T, b T, ..., c T)` returns `Array(Tuple(String, T), ...)`
+in which the `Strings` represents the named fields of the tuple and `T` are the values associated with those names. All values in the tuple should be of the same type.
+
+**Syntax**
+
+``` sql
+tupleToNameValuePairs(tuple)
+```
+
+**Arguments**
+
+-   `tuple` — Named tuple. [Tuple](../../sql-reference/data-types/tuple.md) with any types of values.
+
+**Returned value**
+
+-   An array with (name, value) pairs.
+
+Type: [Array](../../sql-reference/data-types/array.md)([Tuple](../../sql-reference/data-types/tuple.md)([String](../../sql-reference/data-types/string.md), ...)).
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE tupletest (`col` Tuple(user_ID UInt64, session_ID UInt64) ENGINE = Memory;
+
+INSERT INTO tupletest VALUES (tuple( 100, 2502)), (tuple(1,100));
+
+SELECT tupleToNameValuePairs(col) FROM tupletest;
+```
+
+Result:
+
+``` text
+┌─tupleToNameValuePairs(col)────────────┐
+│ [('user_ID',100),('session_ID',2502)] │
+│ [('user_ID',1),('session_ID',100)]    │
+└───────────────────────────────────────┘
+```
+
+It is possible to transform colums to rows using this function:
+
+``` sql
+CREATE TABLE tupletest (`col` Tuple(CPU Float64, Memory Float64, Disk Float64)) ENGINE = Memory;
+
+INSERT INTO tupletest VALUES(tuple(3.3, 5.5, 6.6));
+
+SELECT arrayJoin(tupleToNameValuePairs(col))FROM tupletest;
+```
+
+Result:
+
+``` text
+┌─arrayJoin(tupleToNameValuePairs(col))─┐
+│ ('CPU',3.3)                           │
+│ ('Memory',5.5)                        │
+│ ('Disk',6.6)                          │
+└───────────────────────────────────────┘
+```
+
+If you pass a simple tuple to the function, ClickHouse uses the indexes of the values as their names:
+
+``` sql
+SELECT tupleToNameValuePairs(tuple(3, 2, 1));
+```
+
+Result:
+
+``` text
+┌─tupleToNameValuePairs(tuple(3, 2, 1))─┐
+│ [('1',3),('2',2),('3',1)]             │
+└───────────────────────────────────────┘
+```
+
+## tuplePlus {#tupleplus}
+
+Calculates the sum of corresponding values of two tuples of the same size.
+
+**Syntax**
+
+```sql
+tuplePlus(tuple1, tuple2)
+```
+
+Alias: `vectorSum`.
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple2` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Tuple with the sum.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT tuplePlus((1, 2), (2, 3));
+```
+
+Result:
+
+```text
+┌─tuplePlus((1, 2), (2, 3))─┐
+│ (3,5)                     │
+└───────────────────────────┘
+```
+
+## tupleMinus {#tupleminus}
+
+Calculates the subtraction of corresponding values of two tuples of the same size.
+
+**Syntax**
+
+```sql
+tupleMinus(tuple1, tuple2)
+```
+
+Alias: `vectorDifference`.
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple2` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Tuple with the result of subtraction.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT tupleMinus((1, 2), (2, 3));
+```
+
+Result:
+
+```text
+┌─tupleMinus((1, 2), (2, 3))─┐
+│ (-1,-1)                    │
+└────────────────────────────┘
+```
+
+## tupleMultiply {#tuplemultiply}
+
+Calculates the multiplication of corresponding values of two tuples of the same size.
+
+**Syntax**
+
+```sql
+tupleMultiply(tuple1, tuple2)
+```
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple2` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Tuple with the multiplication.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT tupleMultiply((1, 2), (2, 3));
+```
+
+Result:
+
+```text
+┌─tupleMultiply((1, 2), (2, 3))─┐
+│ (2,6)                         │
+└───────────────────────────────┘
+```
+
+## tupleDivide {#tupledivide}
+
+Calculates the division of corresponding values of two tuples of the same size. Note that division by zero will return `inf`.
+
+**Syntax**
+
+```sql
+tupleDivide(tuple1, tuple2)
+```
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple2` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Tuple with the result of division.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT tupleDivide((1, 2), (2, 3));
+```
+
+Result:
+
+```text
+┌─tupleDivide((1, 2), (2, 3))─┐
+│ (0.5,0.6666666666666666)    │
+└─────────────────────────────┘
+```
+
+## tupleNegate {#tuplenegate}
+
+Calculates the negation of the tuple values.
+
+**Syntax**
+
+```sql
+tupleNegate(tuple)
+```
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Tuple with the result of negation.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT tupleNegate((1,  2));
+```
+
+Result:
+
+```text
+┌─tupleNegate((1, 2))─┐
+│ (-1,-2)             │
+└─────────────────────┘
+```
+
+## tupleMultiplyByNumber {#tuplemultiplybynumber}
+
+Returns a tuple with all values multiplied by a number.
+
+**Syntax**
+
+```sql
+tupleMultiplyByNumber(tuple, number)
+```
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+-   `number` — Multiplier. [Int/UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
+
+**Returned value**
+
+-   Tuple with multiplied values.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT tupleMultiplyByNumber((1, 2), -2.1);
+```
+
+Result:
+
+```text
+┌─tupleMultiplyByNumber((1, 2), -2.1)─┐
+│ (-2.1,-4.2)                         │
+└─────────────────────────────────────┘
+```
+
+## tupleDivideByNumber {#tupledividebynumber}
+
+Returns a tuple with all values divided by a number. Note that division by zero will return `inf`.
+
+**Syntax**
+
+```sql
+tupleDivideByNumber(tuple, number)
+```
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+-   `number` — Divider. [Int/UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
+
+**Returned value**
+
+-   Tuple with divided values.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT tupleDivideByNumber((1, 2), 0.5);
+```
+
+Result:
+
+```text
+┌─tupleDivideByNumber((1, 2), 0.5)─┐
+│ (2,4)                            │
+└──────────────────────────────────┘
+```
+
+## dotProduct {#dotproduct}
+
+Calculates the scalar product of two tuples of the same size.
+
+**Syntax**
+
+```sql
+dotProduct(tuple1, tuple2)
+```
+
+Alias: `scalarProduct`.
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple2` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Scalar product.
+
+Type: [Int/UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT dotProduct((1, 2), (2, 3));
+```
+
+Result:
+
+```text
+┌─dotProduct((1, 2), (2, 3))─┐
+│                          8 │
+└────────────────────────────┘
+```
+
+## L1Norm {#l1norm}
+
+Calculates the sum of absolute values of a tuple.
+
+**Syntax**
+
+```sql
+L1Norm(tuple)
+```
+
+Alias: `normL1`.
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   L1-norm or [taxicab geometry](https://en.wikipedia.org/wiki/Taxicab_geometry) distance.
+
+Type: [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT L1Norm((1, 2));
+```
+
+Result:
+
+```text
+┌─L1Norm((1, 2))─┐
+│              3 │
+└────────────────┘
+```
+
+## L2Norm {#l2norm}
+
+Calculates the square root of the sum of the squares of the tuple values.
+
+**Syntax**
+
+```sql
+L2Norm(tuple)
+```
+
+Alias: `normL2`.
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   L2-norm or [Euclidean distance](https://en.wikipedia.org/wiki/Euclidean_distance).
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT L2Norm((1, 2));
+```
+
+Result:
+
+```text
+┌───L2Norm((1, 2))─┐
+│ 2.23606797749979 │
+└──────────────────┘
+```
+
+## LinfNorm {#linfnorm}
+
+Calculates the maximum of absolute values of a tuple.
+
+**Syntax**
+
+```sql
+LinfNorm(tuple)
+```
+
+Alias: `normLinf`.
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Linf-norm or the maximum absolute value.
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT LinfNorm((1, -2));
+```
+
+Result:
+
+```text
+┌─LinfNorm((1, -2))─┐
+│                 2 │
+└───────────────────┘
+```
+
+## LpNorm {#lpnorm}
+
+Calculates the root of `p`-th power of the sum of the absolute values of a tuple in the power of `p`.
+
+**Syntax**
+
+```sql
+LpNorm(tuple, p)
+```
+
+Alias: `normLp`.
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+-   `p` — The power. Possible values: real number in `[1; inf)`. [UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   [Lp-norm](https://en.wikipedia.org/wiki/Norm_(mathematics)#p-norm)
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT LpNorm((1, -2), 2);
+```
+
+Result:
+
+```text
+┌─LpNorm((1, -2), 2)─┐
+│   2.23606797749979 │
+└────────────────────┘
+```
+
+## L1Distance {#l1distance}
+
+Calculates the distance between two points (the values of the tuples are the coordinates) in `L1` space (1-norm ([taxicab geometry](https://en.wikipedia.org/wiki/Taxicab_geometry) distance)).
+
+**Syntax**
+
+```sql
+L1Distance(tuple1, tuple2)
+```
+
+Alias: `distanceL1`.
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple1` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   1-norm distance.
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT L1Distance((1, 2), (2, 3));
+```
+
+Result:
+
+```text
+┌─L1Distance((1, 2), (2, 3))─┐
+│                          2 │
+└────────────────────────────┘
+```
+
+## L2Distance {#l2distance}
+
+Calculates the distance between two points (the values of the tuples are the coordinates) in Euclidean space ([Euclidean distance](https://en.wikipedia.org/wiki/Euclidean_distance)).
+
+**Syntax**
+
+```sql
+L2Distance(tuple1, tuple2)
+```
+
+Alias: `distanceL2`.
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple1` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   2-norm distance.
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT L2Distance((1, 2), (2, 3));
+```
+
+Result:
+
+```text
+┌─L2Distance((1, 2), (2, 3))─┐
+│         1.4142135623730951 │
+└────────────────────────────┘
+```
+
+## LinfDistance {#linfdistance}
+
+Calculates the distance between two points (the values of the tuples are the coordinates) in `L_{inf}` space ([maximum norm](https://en.wikipedia.org/wiki/Norm_(mathematics)#Maximum_norm_(special_case_of:_infinity_norm,_uniform_norm,_or_supremum_norm))).
+
+**Syntax**
+
+```sql
+LinfDistance(tuple1, tuple2)
+```
+
+Alias: `distanceLinf`.
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple1` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Infinity-norm distance.
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT LinfDistance((1, 2), (2, 3));
+```
+
+Result:
+
+```text
+┌─LinfDistance((1, 2), (2, 3))─┐
+│                            1 │
+└──────────────────────────────┘
+```
+
+## LpDistance {#lpdistance}
+
+Calculates the distance between two points (the values of the tuples are the coordinates) in `Lp` space ([p-norm distance](https://en.wikipedia.org/wiki/Norm_(mathematics)#p-norm)).
+
+**Syntax**
+
+```sql
+LpDistance(tuple1, tuple2, p)
+```
+
+Alias: `distanceLp`.
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple1` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `p` — The power. Possible values: real number from `[1; inf)`. [UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   p-norm distance.
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT LpDistance((1, 2), (2, 3), 3);
+```
+
+Result:
+
+```text
+┌─LpDistance((1, 2), (2, 3), 3)─┐
+│            1.2599210498948732 │
+└───────────────────────────────┘
+```
+
+## L1Normalize {#l1normalize}
+
+Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in `L1` space ([taxicab geometry](https://en.wikipedia.org/wiki/Taxicab_geometry)).
+
+**Syntax**
+
+```sql
+L1Normalize(tuple)
+```
+
+Alias: `normalizeL1`.
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Unit vector.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md) of [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT L1Normalize((1, 2));
+```
+
+Result:
+
+```text
+┌─L1Normalize((1, 2))─────────────────────┐
+│ (0.3333333333333333,0.6666666666666666) │
+└─────────────────────────────────────────┘
+```
+
+## L2Normalize {#l2normalize}
+
+Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in Euclidean space (using [Euclidean distance](https://en.wikipedia.org/wiki/Euclidean_distance)).
+
+**Syntax**
+
+```sql
+L2Normalize(tuple)
+```
+
+Alias: `normalizeL1`.
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Unit vector.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md) of [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT L2Normalize((3, 4));
+```
+
+Result:
+
+```text
+┌─L2Normalize((3, 4))─┐
+│ (0.6,0.8)           │
+└─────────────────────┘
+```
+
+## LinfNormalize {#linfnormalize}
+
+Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in `L_{inf}` space (using [maximum norm](https://en.wikipedia.org/wiki/Norm_(mathematics)#Maximum_norm_(special_case_of:_infinity_norm,_uniform_norm,_or_supremum_norm))).
+
+**Syntax**
+
+```sql
+LinfNormalize(tuple)
+```
+
+Alias: `normalizeLinf `.
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Unit vector.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md) of [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT LinfNormalize((3, 4));
+```
+
+Result:
+
+```text
+┌─LinfNormalize((3, 4))─┐
+│ (0.75,1)              │
+└───────────────────────┘
+```
+
+## LpNormalize {#lpnormalize}
+
+Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in `Lp` space (using [p-norm](https://en.wikipedia.org/wiki/Norm_(mathematics)#p-norm)).
+
+**Syntax**
+
+```sql
+LpNormalize(tuple, p)
+```
+
+Alias: `normalizeLp `.
+
+**Arguments**
+
+-   `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
+-   `p` — The power. Possible values: any number from [1;inf). [UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
+
+**Returned value**
+
+-   Unit vector.
+
+Type: [Tuple](../../sql-reference/data-types/tuple.md) of [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT LpNormalize((3, 4),5);
+```
+
+Result:
+
+```text
+┌─LpNormalize((3, 4), 5)──────────────────┐
+│ (0.7187302630182624,0.9583070173576831) │
+└─────────────────────────────────────────┘
+```
+
+## cosineDistance {#cosinedistance}
+
+Calculates the cosine distance between two vectors (the values of the tuples are the coordinates). The less the returned value is, the more similar are the vectors.
+
+**Syntax**
+
+```sql
+cosineDistance(tuple1, tuple2)
+```
+
+**Arguments**
+
+-   `tuple1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+-   `tuple2` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md).
+
+**Returned value**
+
+-   Cosine of the angle between two vectors substracted from one.
+
+Type: [Float](../../sql-reference/data-types/float.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT cosineDistance((1, 2), (2, 3));
+```
+
+Result:
+
+```text
+┌─cosineDistance((1, 2), (2, 3))─┐
+│           0.007722123286332261 │
+└────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/tuple-map-functions.md b/docs/en/reference/sql-reference/functions/tuple-map-functions.md
new file mode 100644
index 00000000000..a0d62ff5ecb
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/tuple-map-functions.md
@@ -0,0 +1,434 @@
+---
+sidebar_position: 46
+sidebar_label: Working with maps
+---
+
+# Functions for maps {#functions-for-working-with-tuple-maps}
+
+## map {#function-map}
+
+Arranges `key:value` pairs into [Map(key, value)](../../sql-reference/data-types/map.md) data type.
+
+**Syntax**
+
+```sql
+map(key1, value1[, key2, value2, ...])
+```
+
+**Arguments**
+
+-   `key` — The key part of the pair. [String](../../sql-reference/data-types/string.md) or [Integer](../../sql-reference/data-types/int-uint.md).
+-   `value` — The value part of the pair. [String](../../sql-reference/data-types/string.md), [Integer](../../sql-reference/data-types/int-uint.md) or [Array](../../sql-reference/data-types/array.md).
+
+**Returned value**
+
+-   Data structure as `key:value` pairs.
+
+Type: [Map(key, value)](../../sql-reference/data-types/map.md).
+
+**Examples**
+
+Query:
+
+```sql
+SELECT map('key1', number, 'key2', number * 2) FROM numbers(3);
+```
+
+Result:
+
+``` text
+┌─map('key1', number, 'key2', multiply(number, 2))─┐
+│ {'key1':0,'key2':0}                              │
+│ {'key1':1,'key2':2}                              │
+│ {'key1':2,'key2':4}                              │
+└──────────────────────────────────────────────────┘
+```
+
+Query:
+
+```sql
+CREATE TABLE table_map (a Map(String, UInt64)) ENGINE = MergeTree() ORDER BY a;
+INSERT INTO table_map SELECT map('key1', number, 'key2', number * 2) FROM numbers(3);
+SELECT a['key2'] FROM table_map;
+```
+
+Result:
+
+```text
+┌─arrayElement(a, 'key2')─┐
+│                       0 │
+│                       2 │
+│                       4 │
+└─────────────────────────┘
+```
+
+**See Also**
+
+-   [Map(key, value)](../../sql-reference/data-types/map.md) data type
+
+## mapAdd {#function-mapadd}
+
+Collect all the keys and sum corresponding values.
+
+**Syntax**
+
+```sql
+mapAdd(arg1, arg2 [, ...])
+```
+
+**Arguments**
+
+Arguments are [maps](../../sql-reference/data-types/map.md) or [tuples](../../sql-reference/data-types/tuple.md#tuplet1-t2) of two [arrays](../../sql-reference/data-types/array.md#data-type-array), where items in the first array represent keys, and the second array contains values for the each key. All key arrays should have same type, and all value arrays should contain items which are promoted to the one type ([Int64](../../sql-reference/data-types/int-uint.md#int-ranges), [UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges) or [Float64](../../sql-reference/data-types/float.md#float32-float64)). The common promoted type is used as a type for the result array.
+
+**Returned value**
+
+-   Depending on the arguments returns one [map](../../sql-reference/data-types/map.md) or [tuple](../../sql-reference/data-types/tuple.md#tuplet1-t2), where the first array contains the sorted keys and the second array contains values.
+
+**Example**
+
+Query with a tuple:
+
+```sql
+SELECT mapAdd(([toUInt8(1), 2], [1, 1]), ([toUInt8(1), 2], [1, 1])) as res, toTypeName(res) as type;
+```
+
+Result:
+
+```text
+┌─res───────────┬─type───────────────────────────────┐
+│ ([1,2],[2,2]) │ Tuple(Array(UInt8), Array(UInt64)) │
+└───────────────┴────────────────────────────────────┘
+```
+
+Query with `Map` type:
+
+```sql
+SELECT mapAdd(map(1,1), map(1,1));
+```
+
+Result:
+
+```text
+┌─mapAdd(map(1, 1), map(1, 1))─┐
+│ {1:2}                        │
+└──────────────────────────────┘
+```
+
+## mapSubtract {#function-mapsubtract}
+
+Collect all the keys and subtract corresponding values.
+
+**Syntax**
+
+```sql
+mapSubtract(Tuple(Array, Array), Tuple(Array, Array) [, ...])
+```
+
+**Arguments**
+
+Arguments are [maps](../../sql-reference/data-types/map.md) or [tuples](../../sql-reference/data-types/tuple.md#tuplet1-t2) of two [arrays](../../sql-reference/data-types/array.md#data-type-array), where items in the first array represent keys, and the second array contains values for the each key. All key arrays should have same type, and all value arrays should contain items which are promote to the one type ([Int64](../../sql-reference/data-types/int-uint.md#int-ranges), [UInt64](../../sql-reference/data-types/int-uint.md#uint-ranges) or [Float64](../../sql-reference/data-types/float.md#float32-float64)). The common promoted type is used as a type for the result array.
+
+**Returned value**
+
+-   Depending on the arguments returns one [map](../../sql-reference/data-types/map.md) or [tuple](../../sql-reference/data-types/tuple.md#tuplet1-t2), where the first array contains the sorted keys and the second array contains values.
+
+**Example**
+
+Query with a tuple map:
+
+```sql
+SELECT mapSubtract(([toUInt8(1), 2], [toInt32(1), 1]), ([toUInt8(1), 2], [toInt32(2), 1])) as res, toTypeName(res) as type;
+```
+
+Result:
+
+```text
+┌─res────────────┬─type──────────────────────────────┐
+│ ([1,2],[-1,0]) │ Tuple(Array(UInt8), Array(Int64)) │
+└────────────────┴───────────────────────────────────┘
+```
+
+Query with `Map` type:
+
+```sql
+SELECT mapSubtract(map(1,1), map(1,1));
+```
+
+Result:
+
+```text
+┌─mapSubtract(map(1, 1), map(1, 1))─┐
+│ {1:0}                             │
+└───────────────────────────────────┘
+```
+
+## mapPopulateSeries {#function-mappopulateseries}
+
+Fills missing keys in the maps (key and value array pair), where keys are integers. Also, it supports specifying the max key, which is used to extend the keys array.
+
+**Syntax**
+
+```sql
+mapPopulateSeries(keys, values[, max])
+mapPopulateSeries(map[, max])
+```
+
+Generates a map (a tuple with two arrays or a value of `Map` type, depending on the arguments), where keys are a series of numbers, from minimum to maximum keys (or `max` argument if it specified) taken from the map with a step size of one, and corresponding values. If the value is not specified for the key, then it uses the default value in the resulting map. For repeated keys, only the first value (in order of appearing) gets associated with the key.
+
+For array arguments the number of elements in `keys` and `values` must be the same for each row.
+
+**Arguments**
+
+Arguments are [maps](../../sql-reference/data-types/map.md) or two [arrays](../../sql-reference/data-types/array.md#data-type-array), where the first array represent keys, and the second array contains values for the each key.
+
+Mapped arrays:
+
+-   `keys` — Array of keys. [Array](../../sql-reference/data-types/array.md#data-type-array)([Int](../../sql-reference/data-types/int-uint.md#uint-ranges)).
+-   `values` — Array of values. [Array](../../sql-reference/data-types/array.md#data-type-array)([Int](../../sql-reference/data-types/int-uint.md#uint-ranges)).
+-   `max` — Maximum key value. Optional. [Int8, Int16, Int32, Int64, Int128, Int256](../../sql-reference/data-types/int-uint.md#int-ranges).
+
+or
+
+-   `map` — Map with integer keys. [Map](../../sql-reference/data-types/map.md).
+
+**Returned value**
+
+-   Depending on the arguments returns a [map](../../sql-reference/data-types/map.md) or a [tuple](../../sql-reference/data-types/tuple.md#tuplet1-t2) of two [arrays](../../sql-reference/data-types/array.md#data-type-array): keys in sorted order, and values the corresponding keys.
+
+**Example**
+
+Query with mapped arrays:
+
+```sql
+SELECT mapPopulateSeries([1,2,4], [11,22,44], 5) AS res, toTypeName(res) AS type;
+```
+
+Result:
+
+```text
+┌─res──────────────────────────┬─type──────────────────────────────┐
+│ ([1,2,3,4,5],[11,22,0,44,0]) │ Tuple(Array(UInt8), Array(UInt8)) │
+└──────────────────────────────┴───────────────────────────────────┘
+```
+
+Query with `Map` type:
+
+```sql
+SELECT mapPopulateSeries(map(1, 10, 5, 20), 6);
+```
+
+Result:
+
+```text
+┌─mapPopulateSeries(map(1, 10, 5, 20), 6)─┐
+│ {1:10,2:0,3:0,4:0,5:20,6:0}             │
+└─────────────────────────────────────────┘
+```
+
+## mapContains {#mapcontains}
+
+Determines  whether the `map` contains the `key` parameter.
+
+**Syntax**
+
+```sql
+mapContains(map, key)
+```
+
+**Parameters**
+
+-   `map` — Map. [Map](../../sql-reference/data-types/map.md).
+-   `key` — Key. Type matches the type of keys of `map` parameter.
+
+**Returned value**
+
+-   `1` if `map` contains `key`, `0` if not.
+
+Type: [UInt8](../../sql-reference/data-types/int-uint.md).
+
+**Example**
+
+Query:
+
+```sql
+CREATE TABLE test (a Map(String,String)) ENGINE = Memory;
+
+INSERT INTO test VALUES ({'name':'eleven','age':'11'}), ({'number':'twelve','position':'6.0'});
+
+SELECT mapContains(a, 'name') FROM test;
+
+```
+
+Result:
+
+```text
+┌─mapContains(a, 'name')─┐
+│                      1 │
+│                      0 │
+└────────────────────────┘
+```
+
+## mapKeys {#mapkeys}
+
+Returns all keys from the `map` parameter.
+
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [keys](../../sql-reference/data-types/map.md#map-subcolumns) subcolumn instead of reading and processing the whole column data. The query `SELECT mapKeys(m) FROM table` transforms to `SELECT m.keys FROM table`.
+
+**Syntax**
+
+```sql
+mapKeys(map)
+```
+
+**Parameters**
+
+-   `map` — Map. [Map](../../sql-reference/data-types/map.md).
+
+**Returned value**
+
+-   Array containing all keys from the `map`.
+
+Type: [Array](../../sql-reference/data-types/array.md).
+
+**Example**
+
+Query:
+
+```sql
+CREATE TABLE test (a Map(String,String)) ENGINE = Memory;
+
+INSERT INTO test VALUES ({'name':'eleven','age':'11'}), ({'number':'twelve','position':'6.0'});
+
+SELECT mapKeys(a) FROM test;
+```
+
+Result:
+
+```text
+┌─mapKeys(a)────────────┐
+│ ['name','age']        │
+│ ['number','position'] │
+└───────────────────────┘
+```
+
+## mapValues {#mapvalues}
+
+Returns all values from the `map` parameter.
+
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [values](../../sql-reference/data-types/map.md#map-subcolumns) subcolumn instead of reading and processing the whole column data. The query `SELECT mapValues(m) FROM table` transforms to `SELECT m.values FROM table`.
+
+**Syntax**
+
+```sql
+mapValues(map)
+```
+
+**Parameters**
+
+-   `map` — Map. [Map](../../sql-reference/data-types/map.md).
+
+**Returned value**
+
+-   Array containing all the values from `map`.
+
+Type: [Array](../../sql-reference/data-types/array.md).
+
+**Example**
+
+Query:
+
+```sql
+CREATE TABLE test (a Map(String,String)) ENGINE = Memory;
+
+INSERT INTO test VALUES ({'name':'eleven','age':'11'}), ({'number':'twelve','position':'6.0'});
+
+SELECT mapValues(a) FROM test;
+```
+
+Result:
+
+```text
+┌─mapValues(a)─────┐
+│ ['eleven','11']  │
+│ ['twelve','6.0'] │
+└──────────────────┘
+```  
+  
+## mapContainsKeyLike {#mapContainsKeyLike}  
+  
+**Syntax**
+
+```sql
+mapContainsKeyLike(map, pattern)
+```  
+  
+**Parameters**
+  
+-   `map` — Map. [Map](../../sql-reference/data-types/map.md).  
+-   `pattern`  - String pattern to match.  
+  
+**Returned value**
+
+-   `1` if `map` contains `key` like specified pattern, `0` if not.  
+  
+**Example**
+
+Query:
+
+```sql
+CREATE TABLE test (a Map(String,String)) ENGINE = Memory;
+
+INSERT INTO test VALUES ({'abc':'abc','def':'def'}), ({'hij':'hij','klm':'klm'});
+
+SELECT mapContainsKeyLike(a, 'a%') FROM test;
+```  
+  
+Result:  
+  
+```text
+┌─mapContainsKeyLike(a, 'a%')─┐
+│                           1 │
+│                           0 │
+└─────────────────────────────┘  
+```  
+  
+## mapExtractKeyLike {#mapExtractKeyLike}  
+  
+**Syntax**
+
+```sql
+mapExtractKeyLike(map, pattern)
+```  
+  
+**Parameters**
+  
+-   `map` — Map. [Map](../../sql-reference/data-types/map.md).  
+-   `pattern`  - String pattern to match.  
+  
+**Returned value**
+
+- A map contained elements the key of which matchs the specified pattern. If there are no elements matched the pattern, it will return an empty map.
+  
+**Example**
+
+Query:
+
+```sql
+CREATE TABLE test (a Map(String,String)) ENGINE = Memory;
+
+INSERT INTO test VALUES ({'abc':'abc','def':'def'}), ({'hij':'hij','klm':'klm'});
+
+SELECT mapExtractKeyLike(a, 'a%') FROM test;
+```  
+  
+Result:  
+  
+```text
+┌─mapExtractKeyLike(a, 'a%')─┐
+│ {'abc':'abc'}              │
+│ {}                         │
+└────────────────────────────┘
+```  
+  
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/functions/tuple-map-functions/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/functions/type-conversion-functions.md b/docs/en/reference/sql-reference/functions/type-conversion-functions.md
new file mode 100644
index 00000000000..de6ca769589
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/type-conversion-functions.md
@@ -0,0 +1,1743 @@
+---
+sidebar_position: 38
+sidebar_label: Type Conversion
+---
+
+# Type Conversion Functions {#type-conversion-functions}
+
+## Common Issues of Numeric Conversions {#numeric-conversion-issues}
+
+When you convert a value from one to another data type, you should remember that in common case, it is an unsafe operation that can lead to a data loss. A data loss can occur if you try to fit value from a larger data type to a smaller data type, or if you convert values between different data types.
+
+ClickHouse has the [same behavior as C++ programs](https://en.cppreference.com/w/cpp/language/implicit_conversion).
+
+## toInt(8\|16\|32\|64\|128\|256) {#toint8163264128256}
+
+Converts an input value to the [Int](../../sql-reference/data-types/int-uint.md) data type. This function family includes:
+
+-   `toInt8(expr)` — Results in the `Int8` data type.
+-   `toInt16(expr)` — Results in the `Int16` data type.
+-   `toInt32(expr)` — Results in the `Int32` data type.
+-   `toInt64(expr)` — Results in the `Int64` data type.
+-   `toInt128(expr)` — Results in the `Int128` data type.
+-   `toInt256(expr)` — Results in the `Int256` data type.
+
+**Arguments**
+
+-   `expr` — [Expression](../../sql-reference/syntax.md#syntax-expressions) returning a number or a string with the decimal representation of a number. Binary, octal, and hexadecimal representations of numbers are not supported. Leading zeroes are stripped.
+
+**Returned value**
+
+Integer value in the `Int8`, `Int16`, `Int32`, `Int64`, `Int128` or `Int256` data type.
+
+Functions use [rounding towards zero](https://en.wikipedia.org/wiki/Rounding#Rounding_towards_zero), meaning they truncate fractional digits of numbers.
+
+The behavior of functions for the [NaN and Inf](../../sql-reference/data-types/float.md#data_type-float-nan-inf) arguments is undefined. Remember about [numeric convertions issues](#numeric-conversion-issues), when using the functions.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toInt64(nan), toInt32(32), toInt16('16'), toInt8(8.8);
+```
+
+Result:
+
+``` text
+┌─────────toInt64(nan)─┬─toInt32(32)─┬─toInt16('16')─┬─toInt8(8.8)─┐
+│ -9223372036854775808 │          32 │            16 │           8 │
+└──────────────────────┴─────────────┴───────────────┴─────────────┘
+```
+
+## toInt(8\|16\|32\|64\|128\|256)OrZero {#toint8163264orzero}
+
+It takes an argument of type String and tries to parse it into Int (8 \| 16 \| 32 \| 64 \| 128 \| 256). If failed, returns 0.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toInt64OrZero('123123'), toInt8OrZero('123qwe123');
+```
+
+Result:
+
+``` text
+┌─toInt64OrZero('123123')─┬─toInt8OrZero('123qwe123')─┐
+│                  123123 │                         0 │
+└─────────────────────────┴───────────────────────────┘
+```
+
+## toInt(8\|16\|32\|64\|128\|256)OrNull {#toint8163264128256ornull}
+
+It takes an argument of type String and tries to parse it into Int (8 \| 16 \| 32 \| 64 \| 128 \| 256). If failed, returns NULL.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toInt64OrNull('123123'), toInt8OrNull('123qwe123');
+```
+
+Result:
+
+``` text
+┌─toInt64OrNull('123123')─┬─toInt8OrNull('123qwe123')─┐
+│                  123123 │                      ᴺᵁᴸᴸ │
+└─────────────────────────┴───────────────────────────┘
+```
+
+## toInt(8\|16\|32\|64\|128\|256)OrDefault {#toint8163264128256orDefault}
+
+It takes an argument of type String and tries to parse it into Int (8 \| 16 \| 32 \| 64 \| 128 \| 256). If failed, returns the default type value.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toInt64OrDefault('123123', cast('-1' as Int64)), toInt8OrDefault('123qwe123', cast('-1' as Int8));
+```
+
+Result:
+
+``` text
+┌─toInt64OrDefault('123123', CAST('-1', 'Int64'))─┬─toInt8OrDefault('123qwe123', CAST('-1', 'Int8'))─┐
+│                                          123123 │                                               -1 │
+└─────────────────────────────────────────────────┴──────────────────────────────────────────────────┘
+```
+
+
+## toUInt(8\|16\|32\|64\|256) {#touint8163264256}
+
+Converts an input value to the [UInt](../../sql-reference/data-types/int-uint.md) data type. This function family includes:
+
+-   `toUInt8(expr)` — Results in the `UInt8` data type.
+-   `toUInt16(expr)` — Results in the `UInt16` data type.
+-   `toUInt32(expr)` — Results in the `UInt32` data type.
+-   `toUInt64(expr)` — Results in the `UInt64` data type.
+-   `toUInt256(expr)` — Results in the `UInt256` data type.
+
+**Arguments**
+
+-   `expr` — [Expression](../../sql-reference/syntax.md#syntax-expressions) returning a number or a string with the decimal representation of a number. Binary, octal, and hexadecimal representations of numbers are not supported. Leading zeroes are stripped.
+
+**Returned value**
+
+Integer value in the `UInt8`, `UInt16`, `UInt32`, `UInt64` or `UInt256` data type.
+
+Functions use [rounding towards zero](https://en.wikipedia.org/wiki/Rounding#Rounding_towards_zero), meaning they truncate fractional digits of numbers.
+
+The behavior of functions for negative agruments and for the [NaN and Inf](../../sql-reference/data-types/float.md#data_type-float-nan-inf) arguments is undefined. If you pass a string with a negative number, for example `'-32'`, ClickHouse raises an exception. Remember about [numeric convertions issues](#numeric-conversion-issues), when using the functions.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toUInt64(nan), toUInt32(-32), toUInt16('16'), toUInt8(8.8);
+```
+
+Result:
+
+``` text
+┌───────toUInt64(nan)─┬─toUInt32(-32)─┬─toUInt16('16')─┬─toUInt8(8.8)─┐
+│ 9223372036854775808 │    4294967264 │             16 │            8 │
+└─────────────────────┴───────────────┴────────────────┴──────────────┘
+```
+
+## toUInt(8\|16\|32\|64\|256)OrZero {#touint8163264256orzero}
+
+## toUInt(8\|16\|32\|64\|256)OrNull {#touint8163264256ornull}
+
+## toUInt(8\|16\|32\|64\|256)OrDefault {#touint8163264256ordefault}
+
+## toFloat(32\|64) {#tofloat3264}
+
+## toFloat(32\|64)OrZero {#tofloat3264orzero}
+
+## toFloat(32\|64)OrNull {#tofloat3264ornull}
+
+## toFloat(32\|64)OrDefault {#tofloat3264ordefault}
+
+## toDate {#todate}
+
+Alias: `DATE`.
+
+## toDateOrZero {#todateorzero}
+
+## toDateOrNull {#todateornull}
+
+## toDateOrDefault {#todateordefault}
+
+## toDateTime {#todatetime}
+
+## toDateTimeOrZero {#todatetimeorzero}
+
+## toDateTimeOrNull {#todatetimeornull}
+
+## toDateTimeOrDefault {#todatetimeordefault}
+
+## toDate32 {#todate32}
+
+Converts the argument to the [Date32](../../sql-reference/data-types/date32.md) data type. If the value is outside the range returns the border values supported by `Date32`. If the argument has [Date](../../sql-reference/data-types/date.md) type, borders of `Date` are taken into account.
+
+**Syntax**
+
+``` sql
+toDate32(expr)
+```
+
+**Arguments**
+
+-   `expr` — The value. [String](../../sql-reference/data-types/string.md), [UInt32](../../sql-reference/data-types/int-uint.md) or [Date](../../sql-reference/data-types/date.md).
+
+**Returned value**
+
+-   A calendar date.
+
+Type: [Date32](../../sql-reference/data-types/date32.md).
+
+**Example**
+
+1. The value is within the range:
+
+``` sql
+SELECT toDate32('1955-01-01') AS value, toTypeName(value);
+```
+
+``` text
+┌──────value─┬─toTypeName(toDate32('1925-01-01'))─┐
+│ 1955-01-01 │ Date32                             │
+└────────────┴────────────────────────────────────┘
+```
+
+2. The value is outside the range:
+
+``` sql
+SELECT toDate32('1924-01-01') AS value, toTypeName(value);
+```
+
+``` text
+┌──────value─┬─toTypeName(toDate32('1925-01-01'))─┐
+│ 1925-01-01 │ Date32                             │
+└────────────┴────────────────────────────────────┘
+```
+
+3. With `Date`-type argument:
+
+``` sql
+SELECT toDate32(toDate('1924-01-01')) AS value, toTypeName(value);
+```
+
+``` text
+┌──────value─┬─toTypeName(toDate32(toDate('1924-01-01')))─┐
+│ 1970-01-01 │ Date32                                     │
+└────────────┴────────────────────────────────────────────┘
+```
+
+## toDate32OrZero {#todate32-or-zero}
+
+The same as [toDate32](#todate32) but returns the min value of [Date32](../../sql-reference/data-types/date32.md) if invalid argument is received.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toDate32OrZero('1924-01-01'), toDate32OrZero('');
+```
+
+Result:
+
+``` text
+┌─toDate32OrZero('1924-01-01')─┬─toDate32OrZero('')─┐
+│                   1925-01-01 │         1925-01-01 │
+└──────────────────────────────┴────────────────────┘
+```
+
+## toDate32OrNull {#todate32-or-null}
+
+The same as [toDate32](#todate32) but returns `NULL` if invalid argument is received.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toDate32OrNull('1955-01-01'), toDate32OrNull('');
+```
+
+Result:
+
+``` text
+┌─toDate32OrNull('1955-01-01')─┬─toDate32OrNull('')─┐
+│                   1955-01-01 │               ᴺᵁᴸᴸ │
+└──────────────────────────────┴────────────────────┘
+```
+
+## toDate32OrDefault {#todate32-or-default}
+
+Converts the argument to the [Date32](../../sql-reference/data-types/date32.md) data type. If the value is outside the range returns the lower border value supported by `Date32`. If the argument has [Date](../../sql-reference/data-types/date.md) type, borders of `Date` are taken into account. Returns default value if invalid argument is received.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT
+    toDate32OrDefault('1930-01-01', toDate32('2020-01-01')),
+    toDate32OrDefault('xx1930-01-01', toDate32('2020-01-01'));
+```
+
+Result:
+
+``` text
+┌─toDate32OrDefault('1930-01-01', toDate32('2020-01-01'))─┬─toDate32OrDefault('xx1930-01-01', toDate32('2020-01-01'))─┐
+│                                              1930-01-01 │                                                2020-01-01 │
+└─────────────────────────────────────────────────────────┴───────────────────────────────────────────────────────────┘
+```
+
+## toDecimal(32\|64\|128\|256) {#todecimal3264128256}
+
+Converts `value` to the [Decimal](../../sql-reference/data-types/decimal.md) data type with precision of `S`. The `value` can be a number or a string. The `S` (scale) parameter specifies the number of decimal places.
+
+-   `toDecimal32(value, S)`
+-   `toDecimal64(value, S)`
+-   `toDecimal128(value, S)`
+-   `toDecimal256(value, S)`
+
+## toDecimal(32\|64\|128\|256)OrNull {#todecimal3264128256ornull}
+
+Converts an input string to a [Nullable(Decimal(P,S))](../../sql-reference/data-types/decimal.md) data type value. This family of functions include:
+
+-   `toDecimal32OrNull(expr, S)` — Results in `Nullable(Decimal32(S))` data type.
+-   `toDecimal64OrNull(expr, S)` — Results in `Nullable(Decimal64(S))` data type.
+-   `toDecimal128OrNull(expr, S)` — Results in `Nullable(Decimal128(S))` data type.
+-   `toDecimal256OrNull(expr, S)` — Results in `Nullable(Decimal256(S))` data type.
+
+These functions should be used instead of `toDecimal*()` functions, if you prefer to get a `NULL` value instead of an exception in the event of an input value parsing error.
+
+**Arguments**
+
+-   `expr` — [Expression](../../sql-reference/syntax.md#syntax-expressions), returns a value in the [String](../../sql-reference/data-types/string.md) data type. ClickHouse expects the textual representation of the decimal number. For example, `'1.111'`.
+-   `S` — Scale, the number of decimal places in the resulting value.
+
+**Returned value**
+
+A value in the `Nullable(Decimal(P,S))` data type. The value contains:
+
+-   Number with `S` decimal places, if ClickHouse interprets the input string as a number.
+-   `NULL`, if ClickHouse can’t interpret the input string as a number or if the input number contains more than `S` decimal places.
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT toDecimal32OrNull(toString(-1.111), 5) AS val, toTypeName(val);
+```
+
+Result:
+
+``` text
+┌────val─┬─toTypeName(toDecimal32OrNull(toString(-1.111), 5))─┐
+│ -1.111 │ Nullable(Decimal(9, 5))                            │
+└────────┴────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT toDecimal32OrNull(toString(-1.111), 2) AS val, toTypeName(val);
+```
+
+Result:
+
+``` text
+┌──val─┬─toTypeName(toDecimal32OrNull(toString(-1.111), 2))─┐
+│ ᴺᵁᴸᴸ │ Nullable(Decimal(9, 2))                            │
+└──────┴────────────────────────────────────────────────────┘
+```
+
+
+## toDecimal(32\|64\|128\|256)OrDefault {#todecimal3264128256ordefault}
+
+Converts an input string to a [Decimal(P,S)](../../sql-reference/data-types/decimal.md) data type value. This family of functions include:
+
+-   `toDecimal32OrDefault(expr, S)` — Results in `Decimal32(S)` data type.
+-   `toDecimal64OrDefault(expr, S)` — Results in `Decimal64(S)` data type.
+-   `toDecimal128OrDefault(expr, S)` — Results in `Decimal128(S)` data type.
+-   `toDecimal256OrDefault(expr, S)` — Results in `Decimal256(S)` data type.
+
+These functions should be used instead of `toDecimal*()` functions, if you prefer to get a default value instead of an exception in the event of an input value parsing error.
+
+**Arguments**
+
+-   `expr` — [Expression](../../sql-reference/syntax.md#syntax-expressions), returns a value in the [String](../../sql-reference/data-types/string.md) data type. ClickHouse expects the textual representation of the decimal number. For example, `'1.111'`.
+-   `S` — Scale, the number of decimal places in the resulting value.
+
+**Returned value**
+
+A value in the `Decimal(P,S)` data type. The value contains:
+
+-   Number with `S` decimal places, if ClickHouse interprets the input string as a number.
+-   Default `Decimal(P,S)` data type value, if ClickHouse can’t interpret the input string as a number or if the input number contains more than `S` decimal places.
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT toDecimal32OrDefault(toString(-1.111), 5) AS val, toTypeName(val);
+```
+
+Result:
+
+``` text
+┌────val─┬─toTypeName(toDecimal32OrDefault(toString(-1.111), 5))─┐
+│ -1.111 │ Decimal(9, 5)                                         │
+└────────┴───────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT toDecimal32OrDefault(toString(-1.111), 2) AS val, toTypeName(val);
+```
+
+Result:
+
+``` text
+┌─val─┬─toTypeName(toDecimal32OrDefault(toString(-1.111), 2))─┐
+│   0 │ Decimal(9, 2)                                         │
+└─────┴───────────────────────────────────────────────────────┘
+```
+
+## toDecimal(32\|64\|128\|256)OrZero {#todecimal3264128256orzero}
+
+Converts an input value to the [Decimal(P,S)](../../sql-reference/data-types/decimal.md) data type. This family of functions include:
+
+-   `toDecimal32OrZero( expr, S)` — Results in `Decimal32(S)` data type.
+-   `toDecimal64OrZero( expr, S)` — Results in `Decimal64(S)` data type.
+-   `toDecimal128OrZero( expr, S)` — Results in `Decimal128(S)` data type.
+-   `toDecimal256OrZero( expr, S)` — Results in `Decimal256(S)` data type.
+
+These functions should be used instead of `toDecimal*()` functions, if you prefer to get a `0` value instead of an exception in the event of an input value parsing error.
+
+**Arguments**
+
+-   `expr` — [Expression](../../sql-reference/syntax.md#syntax-expressions), returns a value in the [String](../../sql-reference/data-types/string.md) data type. ClickHouse expects the textual representation of the decimal number. For example, `'1.111'`.
+-   `S` — Scale, the number of decimal places in the resulting value.
+
+**Returned value**
+
+A value in the `Nullable(Decimal(P,S))` data type. The value contains:
+
+-   Number with `S` decimal places, if ClickHouse interprets the input string as a number.
+-   0 with `S` decimal places, if ClickHouse can’t interpret the input string as a number or if the input number contains more than `S` decimal places.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toDecimal32OrZero(toString(-1.111), 5) AS val, toTypeName(val);
+```
+
+Result:
+
+``` text
+┌────val─┬─toTypeName(toDecimal32OrZero(toString(-1.111), 5))─┐
+│ -1.111 │ Decimal(9, 5)                                      │
+└────────┴────────────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT toDecimal32OrZero(toString(-1.111), 2) AS val, toTypeName(val);
+```
+
+Result:
+
+``` text
+┌──val─┬─toTypeName(toDecimal32OrZero(toString(-1.111), 2))─┐
+│ 0.00 │ Decimal(9, 2)                                      │
+└──────┴────────────────────────────────────────────────────┘
+```
+
+## toString {#tostring}
+
+Functions for converting between numbers, strings (but not fixed strings), dates, and dates with times.
+All these functions accept one argument.
+
+When converting to or from a string, the value is formatted or parsed using the same rules as for the TabSeparated format (and almost all other text formats). If the string can’t be parsed, an exception is thrown and the request is canceled.
+
+When converting dates to numbers or vice versa, the date corresponds to the number of days since the beginning of the Unix epoch.
+When converting dates with times to numbers or vice versa, the date with time corresponds to the number of seconds since the beginning of the Unix epoch.
+
+The date and date-with-time formats for the toDate/toDateTime functions are defined as follows:
+
+``` text
+YYYY-MM-DD
+YYYY-MM-DD hh:mm:ss
+```
+
+As an exception, if converting from UInt32, Int32, UInt64, or Int64 numeric types to Date, and if the number is greater than or equal to 65536, the number is interpreted as a Unix timestamp (and not as the number of days) and is rounded to the date. This allows support for the common occurrence of writing ‘toDate(unix_timestamp)’, which otherwise would be an error and would require writing the more cumbersome ‘toDate(toDateTime(unix_timestamp))’.
+
+Conversion between a date and date with time is performed the natural way: by adding a null time or dropping the time.
+
+Conversion between numeric types uses the same rules as assignments between different numeric types in C++.
+
+Additionally, the toString function of the DateTime argument can take a second String argument containing the name of the time zone. Example: `Asia/Yekaterinburg` In this case, the time is formatted according to the specified time zone.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT
+    now() AS now_local,
+    toString(now(), 'Asia/Yekaterinburg') AS now_yekat;
+```
+
+Result:
+
+``` text
+┌───────────now_local─┬─now_yekat───────────┐
+│ 2016-06-15 00:11:21 │ 2016-06-15 02:11:21 │
+└─────────────────────┴─────────────────────┘
+```
+
+Also see the `toUnixTimestamp` function.
+
+## toFixedString(s, N) {#tofixedstrings-n}
+
+Converts a String type argument to a FixedString(N) type (a string with fixed length N). N must be a constant.
+If the string has fewer bytes than N, it is padded with null bytes to the right. If the string has more bytes than N, an exception is thrown.
+
+## toStringCutToZero(s) {#tostringcuttozeros}
+
+Accepts a String or FixedString argument. Returns the String with the content truncated at the first zero byte found.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toFixedString('foo', 8) AS s, toStringCutToZero(s) AS s_cut;
+```
+
+Result:
+
+``` text
+┌─s─────────────┬─s_cut─┐
+│ foo\0\0\0\0\0 │ foo   │
+└───────────────┴───────┘
+```
+
+Query:
+
+``` sql
+SELECT toFixedString('foo\0bar', 8) AS s, toStringCutToZero(s) AS s_cut;
+```
+
+Result:
+
+``` text
+┌─s──────────┬─s_cut─┐
+│ foo\0bar\0 │ foo   │
+└────────────┴───────┘
+```
+
+## reinterpretAsUInt(8\|16\|32\|64) {#reinterpretasuint8163264}
+
+## reinterpretAsInt(8\|16\|32\|64) {#reinterpretasint8163264}
+
+## reinterpretAsFloat(32\|64) {#reinterpretasfloat3264}
+
+## reinterpretAsDate {#reinterpretasdate}
+
+## reinterpretAsDateTime {#reinterpretasdatetime}
+
+These functions accept a string and interpret the bytes placed at the beginning of the string as a number in host order (little endian). If the string isn’t long enough, the functions work as if the string is padded with the necessary number of null bytes. If the string is longer than needed, the extra bytes are ignored. A date is interpreted as the number of days since the beginning of the Unix Epoch, and a date with time is interpreted as the number of seconds since the beginning of the Unix Epoch.
+
+## reinterpretAsString {#type_conversion_functions-reinterpretAsString}
+
+This function accepts a number or date or date with time, and returns a string containing bytes representing the corresponding value in host order (little endian). Null bytes are dropped from the end. For example, a UInt32 type value of 255 is a string that is one byte long.
+
+## reinterpretAsFixedString {#reinterpretasfixedstring}
+
+This function accepts a number or date or date with time, and returns a FixedString containing bytes representing the corresponding value in host order (little endian). Null bytes are dropped from the end. For example, a UInt32 type value of 255 is a FixedString that is one byte long.
+
+## reinterpretAsUUID {#reinterpretasuuid}
+
+Accepts 16 bytes string and returns UUID containing bytes representing the corresponding value in network byte order (big-endian). If the string isn't long enough, the function works as if the string is padded with the necessary number of null bytes to the end. If the string longer than 16 bytes, the extra bytes at the end are ignored.
+
+**Syntax**
+
+``` sql
+reinterpretAsUUID(fixed_string)
+```
+
+**Arguments**
+
+-   `fixed_string` — Big-endian byte string. [FixedString](../../sql-reference/data-types/fixedstring.md#fixedstring).
+
+**Returned value**
+
+-   The UUID type value. [UUID](../../sql-reference/data-types/uuid.md#uuid-data-type).
+
+**Examples**
+
+String to UUID.
+
+Query:
+
+``` sql
+SELECT reinterpretAsUUID(reverse(unhex('000102030405060708090a0b0c0d0e0f')));
+```
+
+Result:
+
+``` text
+┌─reinterpretAsUUID(reverse(unhex('000102030405060708090a0b0c0d0e0f')))─┐
+│                                  08090a0b-0c0d-0e0f-0001-020304050607 │
+└───────────────────────────────────────────────────────────────────────┘
+```
+
+Going back and forth from String to UUID.
+
+Query:
+
+``` sql
+WITH
+    generateUUIDv4() AS uuid,
+    identity(lower(hex(reverse(reinterpretAsString(uuid))))) AS str,
+    reinterpretAsUUID(reverse(unhex(str))) AS uuid2
+SELECT uuid = uuid2;
+```
+
+Result:
+
+``` text
+┌─equals(uuid, uuid2)─┐
+│                   1 │
+└─────────────────────┘
+```
+
+## reinterpret(x, T) {#type_conversion_function-reinterpret}
+
+Uses the same source in-memory bytes sequence for `x` value and reinterprets it to destination type.
+
+**Syntax**
+
+``` sql
+reinterpret(x, type)
+```
+
+**Arguments**
+
+-   `x` — Any type.
+-   `type` — Destination type. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Destination type value.
+
+**Examples**
+
+Query:
+```sql
+SELECT reinterpret(toInt8(-1), 'UInt8') as int_to_uint,
+    reinterpret(toInt8(1), 'Float32') as int_to_float,
+    reinterpret('1', 'UInt32') as string_to_int;
+```
+
+Result:
+
+```
+┌─int_to_uint─┬─int_to_float─┬─string_to_int─┐
+│         255 │        1e-45 │            49 │
+└─────────────┴──────────────┴───────────────┘
+```
+
+## CAST(x, T) {#type_conversion_function-cast}
+
+Converts an input value to the specified data type. Unlike the [reinterpret](#type_conversion_function-reinterpret) function, `CAST` tries to present the same value using the new data type. If the conversion can not be done then an exception is raised.
+Several syntax variants are supported.
+
+**Syntax**
+
+``` sql
+CAST(x, T)
+CAST(x AS t)
+x::t
+```
+
+**Arguments**
+
+-   `x` — A value to convert. May be of any type.
+-   `T` — The name of the target data type. [String](../../sql-reference/data-types/string.md).
+-   `t` — The target data type.
+
+**Returned value**
+
+-    Converted value.
+
+:::note    
+If the input value does not fit the bounds of the target type, the result overflows. For example, `CAST(-1, 'UInt8')` returns `255`.
+:::
+
+**Examples**
+
+Query:
+
+```sql
+SELECT
+    CAST(toInt8(-1), 'UInt8') AS cast_int_to_uint,
+    CAST(1.5 AS Decimal(3,2)) AS cast_float_to_decimal,
+    '1'::Int32 AS cast_string_to_int;
+```
+
+Result:
+
+```
+┌─cast_int_to_uint─┬─cast_float_to_decimal─┬─cast_string_to_int─┐
+│              255 │                  1.50 │                  1 │
+└──────────────────┴───────────────────────┴────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT
+    '2016-06-15 23:00:00' AS timestamp,
+    CAST(timestamp AS DateTime) AS datetime,
+    CAST(timestamp AS Date) AS date,
+    CAST(timestamp, 'String') AS string,
+    CAST(timestamp, 'FixedString(22)') AS fixed_string;
+```
+
+Result:
+
+``` text
+┌─timestamp───────────┬────────────datetime─┬───────date─┬─string──────────────┬─fixed_string──────────────┐
+│ 2016-06-15 23:00:00 │ 2016-06-15 23:00:00 │ 2016-06-15 │ 2016-06-15 23:00:00 │ 2016-06-15 23:00:00\0\0\0 │
+└─────────────────────┴─────────────────────┴────────────┴─────────────────────┴───────────────────────────┘
+```
+
+Conversion to FixedString(N) only works for arguments of type [String](../../sql-reference/data-types/string.md) or [FixedString](../../sql-reference/data-types/fixedstring.md).
+
+Type conversion to [Nullable](../../sql-reference/data-types/nullable.md) and back is supported.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toTypeName(x) FROM t_null;
+```
+
+Result:
+
+``` text
+┌─toTypeName(x)─┐
+│ Int8          │
+│ Int8          │
+└───────────────┘
+```
+
+Query:
+
+``` sql
+SELECT toTypeName(CAST(x, 'Nullable(UInt16)')) FROM t_null;
+```
+
+Result:
+
+``` text
+┌─toTypeName(CAST(x, 'Nullable(UInt16)'))─┐
+│ Nullable(UInt16)                        │
+│ Nullable(UInt16)                        │
+└─────────────────────────────────────────┘
+```
+
+**See also**
+
+-   [cast_keep_nullable](../../operations/settings/settings.md#cast_keep_nullable) setting
+
+## accurateCast(x, T) {#type_conversion_function-accurate-cast}
+
+Converts `x` to the `T` data type.
+
+The difference from [cast(x, T)](#type_conversion_function-cast) is that `accurateCast` does not allow overflow of numeric types during cast if type value `x` does not fit the bounds of type `T`. For example, `accurateCast(-1, 'UInt8')` throws an exception.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT cast(-1, 'UInt8') as uint8;
+```
+
+Result:
+
+``` text
+┌─uint8─┐
+│   255 │
+└───────┘
+```
+
+Query:
+
+```sql
+SELECT accurateCast(-1, 'UInt8') as uint8;
+```
+
+Result:
+
+``` text
+Code: 70. DB::Exception: Received from localhost:9000. DB::Exception: Value in column Int8 cannot be safely converted into type UInt8: While processing accurateCast(-1, 'UInt8') AS uint8.
+```
+
+## accurateCastOrNull(x, T) {#type_conversion_function-accurate-cast_or_null}
+
+Converts input value `x` to the specified data type `T`. Always returns [Nullable](../../sql-reference/data-types/nullable.md) type and returns [NULL](../../sql-reference/syntax.md#null-literal) if the casted value is not representable in the target type.
+
+**Syntax**
+
+```sql
+accurateCastOrNull(x, T)
+```
+
+**Parameters**
+
+-   `x` — Input value.
+-   `T` — The name of the returned data type.
+
+**Returned value**
+
+-   The value, converted to the specified data type `T`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toTypeName(accurateCastOrNull(5, 'UInt8'));
+```
+
+Result:
+
+``` text
+┌─toTypeName(accurateCastOrNull(5, 'UInt8'))─┐
+│ Nullable(UInt8)                            │
+└────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT
+    accurateCastOrNull(-1, 'UInt8') as uint8,
+    accurateCastOrNull(128, 'Int8') as int8,
+    accurateCastOrNull('Test', 'FixedString(2)') as fixed_string;
+```
+
+Result:
+
+``` text
+┌─uint8─┬─int8─┬─fixed_string─┐
+│  ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ         │
+└───────┴──────┴──────────────┘
+```
+
+
+## accurateCastOrDefault(x, T[, default_value]) {#type_conversion_function-accurate-cast_or_default}
+
+Converts input value `x` to the specified data type `T`. Returns default type value or `default_value` if specified if the casted value is not representable in the target type.
+
+**Syntax**
+
+```sql
+accurateCastOrDefault(x, T)
+```
+
+**Parameters**
+
+-   `x` — Input value.
+-   `T` — The name of the returned data type.
+-   `default_value` — Default value of returned data type.
+
+**Returned value**
+
+-   The value converted to the specified data type `T`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT toTypeName(accurateCastOrDefault(5, 'UInt8'));
+```
+
+Result:
+
+``` text
+┌─toTypeName(accurateCastOrDefault(5, 'UInt8'))─┐
+│ UInt8                                         │
+└───────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT
+    accurateCastOrDefault(-1, 'UInt8') as uint8,
+    accurateCastOrDefault(-1, 'UInt8', 5) as uint8_default,
+    accurateCastOrDefault(128, 'Int8') as int8,
+    accurateCastOrDefault(128, 'Int8', 5) as int8_default,
+    accurateCastOrDefault('Test', 'FixedString(2)') as fixed_string,
+    accurateCastOrDefault('Test', 'FixedString(2)', 'Te') as fixed_string_default;
+```
+
+Result:
+
+``` text
+┌─uint8─┬─uint8_default─┬─int8─┬─int8_default─┬─fixed_string─┬─fixed_string_default─┐
+│     0 │             5 │    0 │            5 │              │ Te                   │
+└───────┴───────────────┴──────┴──────────────┴──────────────┴──────────────────────┘
+```
+
+## toInterval(Year\|Quarter\|Month\|Week\|Day\|Hour\|Minute\|Second) {#function-tointerval}
+
+Converts a Number type argument to an [Interval](../../sql-reference/data-types/special-data-types/interval.md) data type.
+
+**Syntax**
+
+``` sql
+toIntervalSecond(number)
+toIntervalMinute(number)
+toIntervalHour(number)
+toIntervalDay(number)
+toIntervalWeek(number)
+toIntervalMonth(number)
+toIntervalQuarter(number)
+toIntervalYear(number)
+```
+
+**Arguments**
+
+-   `number` — Duration of interval. Positive integer number.
+
+**Returned values**
+
+-   The value in `Interval` data type.
+
+**Example**
+
+Query:
+
+``` sql
+WITH
+    toDate('2019-01-01') AS date,
+    INTERVAL 1 WEEK AS interval_week,
+    toIntervalWeek(1) AS interval_to_week
+SELECT
+    date + interval_week,
+    date + interval_to_week;
+```
+
+Result:
+
+``` text
+┌─plus(date, interval_week)─┬─plus(date, interval_to_week)─┐
+│                2019-01-08 │                   2019-01-08 │
+└───────────────────────────┴──────────────────────────────┘
+```
+
+## parseDateTimeBestEffort {#parsedatetimebesteffort}
+## parseDateTime32BestEffort {#parsedatetime32besteffort}
+
+Converts a date and time in the [String](../../sql-reference/data-types/string.md) representation to [DateTime](../../sql-reference/data-types/datetime.md#data_type-datetime) data type.
+
+The function parses [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601), [RFC 1123 - 5.2.14 RFC-822 Date and Time Specification](https://tools.ietf.org/html/rfc1123#page-55), ClickHouse’s and some other date and time formats.
+
+**Syntax**
+
+``` sql
+parseDateTimeBestEffort(time_string [, time_zone])
+```
+
+**Arguments**
+
+-   `time_string` — String containing a date and time to convert. [String](../../sql-reference/data-types/string.md).
+-   `time_zone` — Time zone. The function parses `time_string` according to the time zone. [String](../../sql-reference/data-types/string.md).
+
+**Supported non-standard formats**
+
+-   A string containing 9..10 digit [unix timestamp](https://en.wikipedia.org/wiki/Unix_time).
+-   A string with a date and a time component: `YYYYMMDDhhmmss`, `DD/MM/YYYY hh:mm:ss`, `DD-MM-YY hh:mm`, `YYYY-MM-DD hh:mm:ss`, etc.
+-   A string with a date, but no time component: `YYYY`, `YYYYMM`, `YYYY*MM`, `DD/MM/YYYY`, `DD-MM-YY` etc.
+-   A string with a day and time: `DD`, `DD hh`, `DD hh:mm`. In this case `YYYY-MM` are substituted as `2000-01`.
+-   A string that includes the date and time along with time zone offset information: `YYYY-MM-DD hh:mm:ss ±h:mm`, etc. For example, `2020-12-12 17:36:00 -5:00`.
+
+For all of the formats with separator the function parses months names expressed by their full name or by the first three letters of a month name. Examples: `24/DEC/18`, `24-Dec-18`, `01-September-2018`.
+
+**Returned value**
+
+-   `time_string` converted to the `DateTime` data type.
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffort('12/12/2020 12:12:57')
+AS parseDateTimeBestEffort;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffort─┐
+│     2020-12-12 12:12:57 │
+└─────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffort('Sat, 18 Aug 2018 07:22:16 GMT', 'Asia/Istanbul')
+AS parseDateTimeBestEffort;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffort─┐
+│     2018-08-18 10:22:16 │
+└─────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffort('1284101485')
+AS parseDateTimeBestEffort;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffort─┐
+│     2015-07-07 12:04:41 │
+└─────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffort('2018-12-12 10:12:12')
+AS parseDateTimeBestEffort;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffort─┐
+│     2018-12-12 10:12:12 │
+└─────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffort('10 20:19');
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffort('10 20:19')─┐
+│                 2000-01-10 20:19:00 │
+└─────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [ISO 8601 announcement by @xkcd](https://xkcd.com/1179/)
+-   [RFC 1123](https://tools.ietf.org/html/rfc1123)
+-   [toDate](#todate)
+-   [toDateTime](#todatetime)
+
+## parseDateTimeBestEffortUS {#parsedatetimebesteffortUS}
+
+This function is similar to [parseDateTimeBestEffort](#parsedatetimebesteffort), the only difference is that this function prefers US date format (`MM/DD/YYYY` etc.) in case of ambiguity.
+
+**Syntax**
+
+``` sql
+parseDateTimeBestEffortUS(time_string [, time_zone])
+```
+
+**Arguments**
+
+-   `time_string` — String containing a date and time to convert. [String](../../sql-reference/data-types/string.md).
+-   `time_zone` — Time zone. The function parses `time_string` according to the time zone. [String](../../sql-reference/data-types/string.md).
+
+**Supported non-standard formats**
+
+-   A string containing 9..10 digit [unix timestamp](https://en.wikipedia.org/wiki/Unix_time).
+-   A string with a date and a time component: `YYYYMMDDhhmmss`, `MM/DD/YYYY hh:mm:ss`, `MM-DD-YY hh:mm`, `YYYY-MM-DD hh:mm:ss`, etc.
+-   A string with a date, but no time component: `YYYY`, `YYYYMM`, `YYYY*MM`, `MM/DD/YYYY`, `MM-DD-YY` etc.
+-   A string with a day and time: `DD`, `DD hh`, `DD hh:mm`. In this case, `YYYY-MM` are substituted as `2000-01`.
+-   A string that includes the date and time along with time zone offset information: `YYYY-MM-DD hh:mm:ss ±h:mm`, etc. For example, `2020-12-12 17:36:00 -5:00`.
+
+**Returned value**
+
+-   `time_string` converted to the `DateTime` data type.
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUS('09/12/2020 12:12:57')
+AS parseDateTimeBestEffortUS;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUS─┐
+│     2020-09-12 12:12:57   │
+└─────────────────────────——┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUS('09-12-2020 12:12:57')
+AS parseDateTimeBestEffortUS;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUS─┐
+│     2020-09-12 12:12:57   │
+└─────────────────────────——┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUS('09.12.2020 12:12:57')
+AS parseDateTimeBestEffortUS;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUS─┐
+│     2020-09-12 12:12:57   │
+└─────────────────────────——┘
+```
+
+## parseDateTimeBestEffortOrNull {#parsedatetimebesteffortornull}
+## parseDateTime32BestEffortOrNull {#parsedatetime32besteffortornull}
+
+Same as for [parseDateTimeBestEffort](#parsedatetimebesteffort) except that it returns `NULL` when it encounters a date format that cannot be processed.
+
+## parseDateTimeBestEffortOrZero {#parsedatetimebesteffortorzero}
+## parseDateTime32BestEffortOrZero {#parsedatetime32besteffortorzero}
+
+Same as for [parseDateTimeBestEffort](#parsedatetimebesteffort) except that it returns zero date or zero date time when it encounters a date format that cannot be processed.
+
+## parseDateTimeBestEffortUSOrNull {#parsedatetimebesteffortusornull}
+
+Same as [parseDateTimeBestEffortUS](#parsedatetimebesteffortUS) function except that it returns `NULL` when it encounters a date format that cannot be processed.
+
+**Syntax**
+
+``` sql
+parseDateTimeBestEffortUSOrNull(time_string[, time_zone])
+```
+
+**Parameters**
+
+-   `time_string` — String containing a date or date with time to convert. The date must be in the US date format (`MM/DD/YYYY`, etc). [String](../../sql-reference/data-types/string.md).
+-   `time_zone` — [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone). The function parses `time_string` according to the timezone. Optional. [String](../../sql-reference/data-types/string.md).
+
+**Supported non-standard formats**
+
+-   A string containing 9..10 digit [unix timestamp](https://en.wikipedia.org/wiki/Unix_time).
+-   A string with a date and a time components: `YYYYMMDDhhmmss`, `MM/DD/YYYY hh:mm:ss`, `MM-DD-YY hh:mm`, `YYYY-MM-DD hh:mm:ss`, etc.
+-   A string with a date, but no time component: `YYYY`, `YYYYMM`, `YYYY*MM`, `MM/DD/YYYY`, `MM-DD-YY`, etc.
+-   A string with a day and time: `DD`, `DD hh`, `DD hh:mm`. In this case, `YYYY-MM` are substituted with `2000-01`.
+-   A string that includes date and time along with timezone offset information: `YYYY-MM-DD hh:mm:ss ±h:mm`, etc. For example, `2020-12-12 17:36:00 -5:00`.
+
+**Returned values**
+
+-   `time_string` converted to the [DateTime](../../sql-reference/data-types/datetime.md) data type.
+-   `NULL` if the input string cannot be converted to the `DateTime` data type.
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUSOrNull('02/10/2021 21:12:57') AS parseDateTimeBestEffortUSOrNull;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUSOrNull─┐
+│             2021-02-10 21:12:57 │
+└─────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUSOrNull('02-10-2021 21:12:57 GMT', 'Asia/Istanbul') AS parseDateTimeBestEffortUSOrNull;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUSOrNull─┐
+│             2021-02-11 00:12:57 │
+└─────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUSOrNull('02.10.2021') AS parseDateTimeBestEffortUSOrNull;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUSOrNull─┐
+│             2021-02-10 00:00:00 │
+└─────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUSOrNull('10.2021') AS parseDateTimeBestEffortUSOrNull;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUSOrNull─┐
+│                            ᴺᵁᴸᴸ │
+└─────────────────────────────────┘
+```
+
+## parseDateTimeBestEffortUSOrZero {#parsedatetimebesteffortusorzero}
+
+Same as [parseDateTimeBestEffortUS](#parsedatetimebesteffortUS) function except that it returns zero date (`1970-01-01`) or zero date with time (`1970-01-01 00:00:00`) when it encounters a date format that cannot be processed.
+
+**Syntax**
+
+``` sql
+parseDateTimeBestEffortUSOrZero(time_string[, time_zone])
+```
+
+**Parameters**
+
+-   `time_string` — String containing a date or date with time to convert. The date must be in the US date format (`MM/DD/YYYY`, etc). [String](../../sql-reference/data-types/string.md).
+-   `time_zone` — [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone). The function parses `time_string` according to the timezone. Optional. [String](../../sql-reference/data-types/string.md).
+
+**Supported non-standard formats**
+
+-   A string containing 9..10 digit [unix timestamp](https://en.wikipedia.org/wiki/Unix_time).
+-   A string with a date and a time components: `YYYYMMDDhhmmss`, `MM/DD/YYYY hh:mm:ss`, `MM-DD-YY hh:mm`, `YYYY-MM-DD hh:mm:ss`, etc.
+-   A string with a date, but no time component: `YYYY`, `YYYYMM`, `YYYY*MM`, `MM/DD/YYYY`, `MM-DD-YY`, etc.
+-   A string with a day and time: `DD`, `DD hh`, `DD hh:mm`. In this case, `YYYY-MM` are substituted with `2000-01`.
+-   A string that includes date and time along with timezone offset information: `YYYY-MM-DD hh:mm:ss ±h:mm`, etc. For example, `2020-12-12 17:36:00 -5:00`.
+
+**Returned values**
+
+-   `time_string` converted to the [DateTime](../../sql-reference/data-types/datetime.md) data type.
+-   Zero date or zero date with time if the input string cannot be converted to the `DateTime` data type.
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUSOrZero('02/10/2021 21:12:57') AS parseDateTimeBestEffortUSOrZero;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUSOrZero─┐
+│             2021-02-10 21:12:57 │
+└─────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUSOrZero('02-10-2021 21:12:57 GMT', 'Asia/Istanbul') AS parseDateTimeBestEffortUSOrZero;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUSOrZero─┐
+│             2021-02-11 00:12:57 │
+└─────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUSOrZero('02.10.2021') AS parseDateTimeBestEffortUSOrZero;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUSOrZero─┐
+│             2021-02-10 00:00:00 │
+└─────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SELECT parseDateTimeBestEffortUSOrZero('02.2021') AS parseDateTimeBestEffortUSOrZero;
+```
+
+Result:
+
+``` text
+┌─parseDateTimeBestEffortUSOrZero─┐
+│             1970-01-01 00:00:00 │
+└─────────────────────────────────┘
+```
+
+## parseDateTime64BestEffort {#parsedatetime64besteffort}
+
+Same as [parseDateTimeBestEffort](#parsedatetimebesteffort) function but also parse milliseconds and microseconds and returns [DateTime](../../sql-reference/functions/type-conversion-functions.md#data_type-datetime) data type.
+
+**Syntax**
+
+``` sql
+parseDateTime64BestEffort(time_string [, precision [, time_zone]])
+```
+
+**Parameters**
+
+-   `time_string` — String containing a date or date with time to convert. [String](../../sql-reference/data-types/string.md).
+-   `precision` — Required precision. `3` — for milliseconds, `6` — for microseconds. Default — `3`. Optional. [UInt8](../../sql-reference/data-types/int-uint.md).
+-   `time_zone` — [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone). The function parses `time_string` according to the timezone. Optional. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   `time_string` converted to the [DateTime](../../sql-reference/data-types/datetime.md) data type.
+
+**Examples**
+
+Query:
+
+```sql
+SELECT parseDateTime64BestEffort('2021-01-01') AS a, toTypeName(a) AS t
+UNION ALL
+SELECT parseDateTime64BestEffort('2021-01-01 01:01:00.12346') AS a, toTypeName(a) AS t
+UNION ALL
+SELECT parseDateTime64BestEffort('2021-01-01 01:01:00.12346',6) AS a, toTypeName(a) AS t
+UNION ALL
+SELECT parseDateTime64BestEffort('2021-01-01 01:01:00.12346',3,'Asia/Istanbul') AS a, toTypeName(a) AS t
+FORMAT PrettyCompactMonoBlock;
+```
+
+Result:
+
+```
+┌──────────────────────────a─┬─t──────────────────────────────┐
+│ 2021-01-01 01:01:00.123000 │ DateTime64(3)                  │
+│ 2021-01-01 00:00:00.000000 │ DateTime64(3)                  │
+│ 2021-01-01 01:01:00.123460 │ DateTime64(6)                  │
+│ 2020-12-31 22:01:00.123000 │ DateTime64(3, 'Asia/Istanbul') │
+└────────────────────────────┴────────────────────────────────┘
+```
+
+## parseDateTime64BestEffortOrNull {#parsedatetime32besteffortornull}
+
+Same as for [parseDateTime64BestEffort](#parsedatetime64besteffort) except that it returns `NULL` when it encounters a date format that cannot be processed.
+
+## parseDateTime64BestEffortOrZero {#parsedatetime64besteffortorzero}
+
+Same as for [parseDateTime64BestEffort](#parsedatetimebesteffort) except that it returns zero date or zero date time when it encounters a date format that cannot be processed.
+
+
+## toLowCardinality {#tolowcardinality}
+
+Converts input parameter to the [LowCardianlity](../../sql-reference/data-types/lowcardinality.md) version of same data type.
+
+To convert data from the `LowCardinality` data type use the [CAST](#type_conversion_function-cast) function. For example, `CAST(x as String)`.
+
+**Syntax**
+
+```sql
+toLowCardinality(expr)
+```
+
+**Arguments**
+
+-   `expr` — [Expression](../../sql-reference/syntax.md#syntax-expressions) resulting in one of the [supported data types](../../sql-reference/data-types/index.md#data_types).
+
+**Returned values**
+
+-   Result of `expr`.
+
+Type: `LowCardinality(expr_result_type)`
+
+**Example**
+
+Query:
+
+```sql
+SELECT toLowCardinality('1');
+```
+
+Result:
+
+``` text
+┌─toLowCardinality('1')─┐
+│ 1                     │
+└───────────────────────┘
+```
+
+## toUnixTimestamp64Milli {#tounixtimestamp64milli}
+
+## toUnixTimestamp64Micro {#tounixtimestamp64micro}
+
+## toUnixTimestamp64Nano {#tounixtimestamp64nano}
+
+Converts a `DateTime64` to a `Int64` value with fixed sub-second precision. Input value is scaled up or down appropriately depending on it precision.
+
+:::note    
+The output value is a timestamp in UTC, not in the timezone of `DateTime64`.
+:::
+
+**Syntax**
+
+```sql
+toUnixTimestamp64Milli(value)
+```
+
+**Arguments**
+
+-   `value` — DateTime64 value with any precision.
+
+**Returned value**
+
+-   `value` converted to the `Int64` data type.
+
+**Examples**
+
+Query:
+
+```sql
+WITH toDateTime64('2019-09-16 19:20:12.345678910', 6) AS dt64
+SELECT toUnixTimestamp64Milli(dt64);
+```
+
+Result:
+
+``` text
+┌─toUnixTimestamp64Milli(dt64)─┐
+│                1568650812345 │
+└──────────────────────────────┘
+```
+
+Query:
+
+``` sql
+WITH toDateTime64('2019-09-16 19:20:12.345678910', 6) AS dt64
+SELECT toUnixTimestamp64Nano(dt64);
+```
+
+Result:
+
+``` text
+┌─toUnixTimestamp64Nano(dt64)─┐
+│         1568650812345678000 │
+└─────────────────────────────┘
+```
+
+## fromUnixTimestamp64Milli {#fromunixtimestamp64milli}
+
+## fromUnixTimestamp64Micro {#fromunixtimestamp64micro}
+
+## fromUnixTimestamp64Nano {#fromunixtimestamp64nano}
+
+Converts an `Int64` to a `DateTime64` value with fixed sub-second precision and optional timezone. Input value is scaled up or down appropriately depending on it’s precision. Please note that input value is treated as UTC timestamp, not timestamp at given (or implicit) timezone.
+
+**Syntax**
+
+``` sql
+fromUnixTimestamp64Milli(value [, ti])
+```
+
+**Arguments**
+
+-   `value` — `Int64` value with any precision.
+-   `timezone` — `String` (optional) timezone name of the result.
+
+**Returned value**
+
+-   `value` converted to the `DateTime64` data type.
+
+**Example**
+
+Query:
+
+``` sql
+WITH CAST(1234567891011, 'Int64') AS i64
+SELECT fromUnixTimestamp64Milli(i64, 'UTC');
+```
+
+Result:
+
+``` text
+┌─fromUnixTimestamp64Milli(i64, 'UTC')─┐
+│              2009-02-13 23:31:31.011 │
+└──────────────────────────────────────┘
+```
+
+## formatRow {#formatrow}
+
+Converts arbitrary expressions into a string via given format.
+
+**Syntax**
+
+``` sql
+formatRow(format, x, y, ...)
+```
+
+**Arguments**
+
+-   `format` — Text format. For example, [CSV](../../interfaces/formats.md#csv), [TSV](../../interfaces/formats.md#tabseparated).
+-   `x`,`y`, ... — Expressions.
+
+**Returned value**
+
+-   A formatted string (for text formats it's usually terminated with the new line character).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT formatRow('CSV', number, 'good')
+FROM numbers(3);
+```
+
+Result:
+
+``` text
+┌─formatRow('CSV', number, 'good')─┐
+│ 0,"good"
+                         │
+│ 1,"good"
+                         │
+│ 2,"good"
+                         │
+└──────────────────────────────────┘
+```
+
+## formatRowNoNewline {#formatrownonewline}
+
+Converts arbitrary expressions into a string via given format. The function trims the last `\n` if any.
+
+**Syntax**
+
+``` sql
+formatRowNoNewline(format, x, y, ...)
+```
+
+**Arguments**
+
+-   `format` — Text format. For example, [CSV](../../interfaces/formats.md#csv), [TSV](../../interfaces/formats.md#tabseparated).
+-   `x`,`y`, ... — Expressions.
+
+**Returned value**
+
+-   A formatted string.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT formatRowNoNewline('CSV', number, 'good')
+FROM numbers(3);
+```
+
+Result:
+
+``` text
+┌─formatRowNoNewline('CSV', number, 'good')─┐
+│ 0,"good"                                  │
+│ 1,"good"                                  │
+│ 2,"good"                                  │
+└───────────────────────────────────────────┘
+```
+
+## snowflakeToDateTime {#snowflaketodatetime}
+
+Extracts time from [Snowflake ID](https://en.wikipedia.org/wiki/Snowflake_ID) as [DateTime](../data-types/datetime.md) format.
+
+**Syntax**
+
+``` sql
+snowflakeToDateTime(value [, time_zone])
+```
+
+**Parameters**
+
+-   `value` — Snowflake ID. [Int64](../data-types/int-uint.md).
+-   `time_zone` — [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone). The function parses `time_string` according to the timezone. Optional. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-  Input value converted to the [DateTime](../data-types/datetime.md) data type.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT snowflakeToDateTime(CAST('1426860702823350272', 'Int64'), 'UTC');
+```
+
+Result:
+
+``` text
+
+┌─snowflakeToDateTime(CAST('1426860702823350272', 'Int64'), 'UTC')─┐
+│                                              2021-08-15 10:57:56 │
+└──────────────────────────────────────────────────────────────────┘
+```
+
+## snowflakeToDateTime64 {#snowflaketodatetime64}
+
+Extracts time from [Snowflake ID](https://en.wikipedia.org/wiki/Snowflake_ID) as [DateTime64](../data-types/datetime64.md) format.
+
+**Syntax**
+
+``` sql
+snowflakeToDateTime64(value [, time_zone])
+```
+
+**Parameters**
+
+-   `value` — Snowflake ID. [Int64](../data-types/int-uint.md).
+-   `time_zone` — [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone). The function parses `time_string` according to the timezone. Optional. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-  Input value converted to the [DateTime64](../data-types/datetime64.md) data type.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT snowflakeToDateTime64(CAST('1426860802823350272', 'Int64'), 'UTC');
+```
+
+Result:
+
+``` text
+
+┌─snowflakeToDateTime64(CAST('1426860802823350272', 'Int64'), 'UTC')─┐
+│                                            2021-08-15 10:58:19.841 │
+└────────────────────────────────────────────────────────────────────┘
+```
+
+## dateTimeToSnowflake {#datetimetosnowflake}
+
+Converts [DateTime](../data-types/datetime.md) value to the first [Snowflake ID](https://en.wikipedia.org/wiki/Snowflake_ID) at the giving time.
+
+**Syntax**
+
+``` sql
+dateTimeToSnowflake(value)
+```
+
+**Parameters**
+
+-   `value` — Date and time. [DateTime](../../sql-reference/data-types/datetime.md).
+
+**Returned value**
+
+-   Input value converted to the [Int64](../data-types/int-uint.md) data type as the first Snowflake ID at that time.
+
+**Example**
+
+Query:
+
+``` sql
+WITH toDateTime('2021-08-15 18:57:56', 'Asia/Shanghai') AS dt SELECT dateTimeToSnowflake(dt);
+```
+
+Result:
+
+``` text
+┌─dateTimeToSnowflake(dt)─┐
+│     1426860702823350272 │
+└─────────────────────────┘
+```
+
+## dateTime64ToSnowflake {#datetime64tosnowflake}
+
+Convert [DateTime64](../data-types/datetime64.md) to the first [Snowflake ID](https://en.wikipedia.org/wiki/Snowflake_ID) at the giving time.
+
+**Syntax**
+
+``` sql
+dateTime64ToSnowflake(value)
+```
+
+**Parameters**
+
+-   `value` — Date and time. [DateTime64](../../sql-reference/data-types/datetime64.md).
+
+**Returned value**
+
+-   Input value converted to the [Int64](../data-types/int-uint.md) data type as the first Snowflake ID at that time.
+
+**Example**
+
+Query:
+
+``` sql
+WITH toDateTime64('2021-08-15 18:57:56.492', 3, 'Asia/Shanghai') AS dt64 SELECT dateTime64ToSnowflake(dt64);
+```
+
+Result:
+
+``` text
+┌─dateTime64ToSnowflake(dt64)─┐
+│         1426860704886947840 │
+└─────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/functions/url-functions.md b/docs/en/reference/sql-reference/functions/url-functions.md
new file mode 100644
index 00000000000..c91029c4fce
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/url-functions.md
@@ -0,0 +1,467 @@
+---
+sidebar_position: 54
+sidebar_label: URLs
+---
+
+# Functions for Working with URLs {#functions-for-working-with-urls}
+
+All these functions do not follow the RFC. They are maximally simplified for improved performance.
+
+## Functions that Extract Parts of a URL {#functions-that-extract-parts-of-a-url}
+
+If the relevant part isn’t present in a URL, an empty string is returned.
+
+### protocol {#protocol}
+
+Extracts the protocol from a URL.
+
+Examples of typical returned values: http, https, ftp, mailto, tel, magnet…
+
+### domain {#domain}
+
+Extracts the hostname from a URL.
+
+``` sql
+domain(url)
+```
+
+**Arguments**
+
+-   `url` — URL. Type: [String](../../sql-reference/data-types/string.md).
+
+The URL can be specified with or without a scheme. Examples:
+
+``` text
+svn+ssh://some.svn-hosting.com:80/repo/trunk
+some.svn-hosting.com:80/repo/trunk
+https://clickhouse.com/time/
+```
+
+For these examples, the `domain` function returns the following results:
+
+``` text
+some.svn-hosting.com
+some.svn-hosting.com
+clickhouse.com
+```
+
+**Returned values**
+
+-   Host name. If ClickHouse can parse the input string as a URL.
+-   Empty string. If ClickHouse can’t parse the input string as a URL.
+
+Type: `String`.
+
+**Example**
+
+``` sql
+SELECT domain('svn+ssh://some.svn-hosting.com:80/repo/trunk');
+```
+
+``` text
+┌─domain('svn+ssh://some.svn-hosting.com:80/repo/trunk')─┐
+│ some.svn-hosting.com                                   │
+└────────────────────────────────────────────────────────┘
+```
+
+### domainWithoutWWW {#domainwithoutwww}
+
+Returns the domain and removes no more than one ‘www.’ from the beginning of it, if present.
+
+### topLevelDomain {#topleveldomain}
+
+Extracts the the top-level domain from a URL.
+
+``` sql
+topLevelDomain(url)
+```
+
+**Arguments**
+
+-   `url` — URL. Type: [String](../../sql-reference/data-types/string.md).
+
+The URL can be specified with or without a scheme. Examples:
+
+``` text
+svn+ssh://some.svn-hosting.com:80/repo/trunk
+some.svn-hosting.com:80/repo/trunk
+https://clickhouse.com/time/
+```
+
+**Returned values**
+
+-   Domain name. If ClickHouse can parse the input string as a URL.
+-   Empty string. If ClickHouse cannot parse the input string as a URL.
+
+Type: `String`.
+
+**Example**
+
+``` sql
+SELECT topLevelDomain('svn+ssh://www.some.svn-hosting.com:80/repo/trunk');
+```
+
+``` text
+┌─topLevelDomain('svn+ssh://www.some.svn-hosting.com:80/repo/trunk')─┐
+│ com                                                                │
+└────────────────────────────────────────────────────────────────────┘
+```
+
+### firstSignificantSubdomain {#firstsignificantsubdomain}
+
+Returns the “first significant subdomain”. The first significant subdomain is a second-level domain if it is ‘com’, ‘net’, ‘org’, or ‘co’. Otherwise, it is a third-level domain. For example, `firstSignificantSubdomain (‘https://news.clickhouse.com/’) = ‘clickhouse’, firstSignificantSubdomain (‘https://news.clickhouse.com.tr/’) = ‘clickhouse’`. The list of “insignificant” second-level domains and other implementation details may change in the future.
+
+### cutToFirstSignificantSubdomain {#cuttofirstsignificantsubdomain}
+
+Returns the part of the domain that includes top-level subdomains up to the “first significant subdomain” (see the explanation above).
+
+For example:
+
+-   `cutToFirstSignificantSubdomain('https://news.clickhouse.com.tr/') = 'clickhouse.com.tr'`.
+-   `cutToFirstSignificantSubdomain('www.tr') = 'tr'`.
+-   `cutToFirstSignificantSubdomain('tr') = ''`.
+
+### cutToFirstSignificantSubdomainWithWWW {#cuttofirstsignificantsubdomainwithwww}
+
+Returns the part of the domain that includes top-level subdomains up to the “first significant subdomain”, without stripping "www".
+
+For example:
+
+-   `cutToFirstSignificantSubdomain('https://news.clickhouse.com.tr/') = 'clickhouse.com.tr'`.
+-   `cutToFirstSignificantSubdomain('www.tr') = 'www.tr'`.
+-   `cutToFirstSignificantSubdomain('tr') = ''`.
+
+### cutToFirstSignificantSubdomainCustom {#cuttofirstsignificantsubdomaincustom}
+
+Returns the part of the domain that includes top-level subdomains up to the first significant subdomain. Accepts custom [TLD list](https://en.wikipedia.org/wiki/List_of_Internet_top-level_domains) name.
+
+Can be useful if you need fresh TLD list or you have custom.
+
+Configuration example:
+
+```xml
+<!-- <top_level_domains_path>/var/lib/clickhouse/top_level_domains/</top_level_domains_path> -->
+<top_level_domains_lists>
+    <!-- https://publicsuffix.org/list/public_suffix_list.dat -->
+    <public_suffix_list>public_suffix_list.dat</public_suffix_list>
+    <!-- NOTE: path is under top_level_domains_path -->
+</top_level_domains_lists>
+```
+
+**Syntax**
+
+``` sql
+cutToFirstSignificantSubdomain(URL, TLD)
+```
+
+**Parameters**
+
+-   `URL` — URL. [String](../../sql-reference/data-types/string.md).
+-   `TLD` — Custom TLD list name. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Part of the domain that includes top-level subdomains up to the first significant subdomain.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT cutToFirstSignificantSubdomainCustom('bar.foo.there-is-no-such-domain', 'public_suffix_list');
+```
+
+Result:
+
+```text
+┌─cutToFirstSignificantSubdomainCustom('bar.foo.there-is-no-such-domain', 'public_suffix_list')─┐
+│ foo.there-is-no-such-domain                                                                   │
+└───────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [firstSignificantSubdomain](#firstsignificantsubdomain).
+
+### cutToFirstSignificantSubdomainCustomWithWWW {#cuttofirstsignificantsubdomaincustomwithwww}
+
+Returns the part of the domain that includes top-level subdomains up to the first significant subdomain without stripping `www`. Accepts custom TLD list name.
+
+Can be useful if you need fresh TLD list or you have custom.
+
+Configuration example:
+
+```xml
+<!-- <top_level_domains_path>/var/lib/clickhouse/top_level_domains/</top_level_domains_path> -->
+<top_level_domains_lists>
+    <!-- https://publicsuffix.org/list/public_suffix_list.dat -->
+    <public_suffix_list>public_suffix_list.dat</public_suffix_list>
+    <!-- NOTE: path is under top_level_domains_path -->
+</top_level_domains_lists>
+```
+
+**Syntax**
+
+```sql
+cutToFirstSignificantSubdomainCustomWithWWW(URL, TLD)
+```
+
+**Parameters**
+
+-   `URL` — URL. [String](../../sql-reference/data-types/string.md).
+-   `TLD` — Custom TLD list name. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   Part of the domain that includes top-level subdomains up to the first significant subdomain without stripping `www`.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT cutToFirstSignificantSubdomainCustomWithWWW('www.foo', 'public_suffix_list');
+```
+
+Result:
+
+```text
+┌─cutToFirstSignificantSubdomainCustomWithWWW('www.foo', 'public_suffix_list')─┐
+│ www.foo                                                                      │
+└──────────────────────────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [firstSignificantSubdomain](#firstsignificantsubdomain).
+
+### firstSignificantSubdomainCustom {#firstsignificantsubdomaincustom}
+
+Returns the first significant subdomain. Accepts customs TLD list name.
+
+Can be useful if you need fresh TLD list or you have custom.
+
+Configuration example:
+
+```xml
+<!-- <top_level_domains_path>/var/lib/clickhouse/top_level_domains/</top_level_domains_path> -->
+<top_level_domains_lists>
+    <!-- https://publicsuffix.org/list/public_suffix_list.dat -->
+    <public_suffix_list>public_suffix_list.dat</public_suffix_list>
+    <!-- NOTE: path is under top_level_domains_path -->
+</top_level_domains_lists>
+```
+
+**Syntax**
+
+```sql
+firstSignificantSubdomainCustom(URL, TLD)
+```
+
+**Parameters**
+
+-   `URL` — URL. [String](../../sql-reference/data-types/string.md).
+-   `TLD` — Custom TLD list name. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   First significant subdomain.
+
+Type: [String](../../sql-reference/data-types/string.md).
+
+**Example**
+
+Query:
+
+```sql
+SELECT firstSignificantSubdomainCustom('bar.foo.there-is-no-such-domain', 'public_suffix_list');
+```
+
+Result:
+
+```text
+┌─firstSignificantSubdomainCustom('bar.foo.there-is-no-such-domain', 'public_suffix_list')─┐
+│ foo                                                                                      │
+└──────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+-   [firstSignificantSubdomain](#firstsignificantsubdomain).
+
+### port(URL\[, default_port = 0\]) {#port}
+
+Returns the port or `default_port` if there is no port in the URL (or in case of validation error).
+
+### path {#path}
+
+Returns the path. Example: `/top/news.html` The path does not include the query string.
+
+### pathFull {#pathfull}
+
+The same as above, but including query string and fragment. Example: /top/news.html?page=2#comments
+
+### queryString {#querystring}
+
+Returns the query string. Example: page=1&lr=213. query-string does not include the initial question mark, as well as # and everything after #.
+
+### fragment {#fragment}
+
+Returns the fragment identifier. fragment does not include the initial hash symbol.
+
+### queryStringAndFragment {#querystringandfragment}
+
+Returns the query string and fragment identifier. Example: page=1#29390.
+
+### extractURLParameter(URL, name) {#extracturlparameterurl-name}
+
+Returns the value of the ‘name’ parameter in the URL, if present. Otherwise, an empty string. If there are many parameters with this name, it returns the first occurrence. This function works under the assumption that the parameter name is encoded in the URL exactly the same way as in the passed argument.
+
+### extractURLParameters(URL) {#extracturlparametersurl}
+
+Returns an array of name=value strings corresponding to the URL parameters. The values are not decoded in any way.
+
+### extractURLParameterNames(URL) {#extracturlparameternamesurl}
+
+Returns an array of name strings corresponding to the names of URL parameters. The values are not decoded in any way.
+
+### URLHierarchy(URL) {#urlhierarchyurl}
+
+Returns an array containing the URL, truncated at the end by the symbols /,? in the path and query-string. Consecutive separator characters are counted as one. The cut is made in the position after all the consecutive separator characters.
+
+### URLPathHierarchy(URL) {#urlpathhierarchyurl}
+
+The same as above, but without the protocol and host in the result. The / element (root) is not included.
+
+``` text
+URLPathHierarchy('https://example.com/browse/CONV-6788') =
+[
+    '/browse/',
+    '/browse/CONV-6788'
+]
+```
+
+### encodeURLComponent(URL) {#encodeurlcomponenturl}
+
+Returns the encoded URL.
+Example:
+
+``` sql
+SELECT encodeURLComponent('http://127.0.0.1:8123/?query=SELECT 1;') AS EncodedURL;
+```
+
+``` text
+┌─EncodedURL───────────────────────────────────────────────┐
+│ http%3A%2F%2F127.0.0.1%3A8123%2F%3Fquery%3DSELECT%201%3B │
+└──────────────────────────────────────────────────────────┘
+```
+
+### decodeURLComponent(URL) {#decodeurlcomponenturl}
+
+Returns the decoded URL.
+Example:
+
+``` sql
+SELECT decodeURLComponent('http://127.0.0.1:8123/?query=SELECT%201%3B') AS DecodedURL;
+```
+
+``` text
+┌─DecodedURL─────────────────────────────┐
+│ http://127.0.0.1:8123/?query=SELECT 1; │
+└────────────────────────────────────────┘
+```
+
+### encodeURLFormComponent(URL) {#encodeurlformcomponenturl}
+
+Returns the encoded URL. Follows rfc-1866, space(` `) is encoded as plus(`+`).
+Example:
+
+``` sql
+SELECT encodeURLFormComponent('http://127.0.0.1:8123/?query=SELECT 1 2+3') AS EncodedURL;
+```
+
+``` text
+┌─EncodedURL────────────────────────────────────────────────┐
+│ http%3A%2F%2F127.0.0.1%3A8123%2F%3Fquery%3DSELECT+1+2%2B3 │
+└───────────────────────────────────────────────────────────┘
+```
+
+### decodeURLFormComponent(URL) {#decodeurlformcomponenturl}
+
+Returns the decoded URL. Follows rfc-1866, plain plus(`+`) is decoded as space(` `).
+Example:
+
+``` sql
+SELECT decodeURLFormComponent('http://127.0.0.1:8123/?query=SELECT%201+2%2B3') AS DecodedURL;
+```
+
+``` text
+┌─DecodedURL────────────────────────────────┐
+│ http://127.0.0.1:8123/?query=SELECT 1 2+3 │
+└───────────────────────────────────────────┘
+```
+
+### netloc {#netloc}
+
+Extracts network locality (`username:password@host:port`) from a URL.
+
+**Syntax**
+
+``` sql
+netloc(URL)
+```
+
+**Arguments**
+
+-   `url` — URL. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   `username:password@host:port`.
+
+Type: `String`.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT netloc('http://paul@www.example.com:80/');
+```
+
+Result:
+
+``` text
+┌─netloc('http://paul@www.example.com:80/')─┐
+│ paul@www.example.com:80                   │
+└───────────────────────────────────────────┘
+```
+
+## Functions that Remove Part of a URL {#functions-that-remove-part-of-a-url}
+
+If the URL does not have anything similar, the URL remains unchanged.
+
+### cutWWW {#cutwww}
+
+Removes no more than one ‘www.’ from the beginning of the URL’s domain, if present.
+
+### cutQueryString {#cutquerystring}
+
+Removes query string. The question mark is also removed.
+
+### cutFragment {#cutfragment}
+
+Removes the fragment identifier. The number sign is also removed.
+
+### cutQueryStringAndFragment {#cutquerystringandfragment}
+
+Removes the query string and fragment identifier. The question mark and number sign are also removed.
+
+### cutURLParameter(URL, name) {#cuturlparameterurl-name}
+
+Removes the ‘name’ URL parameter, if present. This function works under the assumption that the parameter name is encoded in the URL exactly the same way as in the passed argument.
+
diff --git a/docs/en/reference/sql-reference/functions/uuid-functions.md b/docs/en/reference/sql-reference/functions/uuid-functions.md
new file mode 100644
index 00000000000..d23b505a93f
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/uuid-functions.md
@@ -0,0 +1,266 @@
+---
+sidebar_position: 53
+sidebar_label: UUID
+---
+
+# Functions for Working with UUID {#functions-for-working-with-uuid}
+
+The functions for working with UUID are listed below.
+
+## generateUUIDv4 {#uuid-function-generate}
+
+Generates the [UUID](../data-types/uuid.md) of [version 4](https://tools.ietf.org/html/rfc4122#section-4.4).
+
+``` sql
+generateUUIDv4()
+```
+
+**Returned value**
+
+The UUID type value.
+
+**Usage example**
+
+This example demonstrates creating a table with the UUID type column and inserting a value into the table.
+
+``` sql
+CREATE TABLE t_uuid (x UUID) ENGINE=TinyLog
+
+INSERT INTO t_uuid SELECT generateUUIDv4()
+
+SELECT * FROM t_uuid
+```
+
+``` text
+┌────────────────────────────────────x─┐
+│ f4bf890f-f9dc-4332-ad5c-0c18e73f28e9 │
+└──────────────────────────────────────┘
+```
+
+## empty {#empty}
+
+Checks whether the input UUID is empty.
+
+**Syntax**
+
+```sql
+empty(UUID)
+```
+
+The UUID is considered empty if it contains all zeros (zero UUID).
+
+The function also works for [arrays](array-functions.md#function-empty) or [strings](string-functions.md#empty).
+
+**Arguments**
+
+-   `x` — Input UUID. [UUID](../data-types/uuid.md).
+
+**Returned value**
+
+-   Returns `1` for an empty UUID or `0` for a non-empty UUID. 
+
+Type: [UInt8](../data-types/int-uint.md).
+
+**Example**
+
+To generate the UUID value, ClickHouse provides the [generateUUIDv4](#uuid-function-generate) function.
+
+Query:
+
+```sql
+SELECT empty(generateUUIDv4());
+```
+
+Result:
+
+```text
+┌─empty(generateUUIDv4())─┐
+│                       0 │
+└─────────────────────────┘
+```
+
+## notEmpty {#notempty}
+
+Checks whether the input UUID is non-empty.
+
+**Syntax**
+
+```sql
+notEmpty(UUID)
+```
+
+The UUID is considered empty if it contains all zeros (zero UUID).
+
+The function also works for [arrays](array-functions.md#function-notempty) or [strings](string-functions.md#notempty).
+
+**Arguments**
+
+-   `x` — Input UUID. [UUID](../data-types/uuid.md).
+
+**Returned value**
+
+-   Returns `1` for a non-empty UUID or `0` for an empty UUID. 
+
+Type: [UInt8](../data-types/int-uint.md).
+
+**Example**
+
+To generate the UUID value, ClickHouse provides the [generateUUIDv4](#uuid-function-generate) function.
+
+Query:
+
+```sql
+SELECT notEmpty(generateUUIDv4());
+```
+
+Result:
+
+```text
+┌─notEmpty(generateUUIDv4())─┐
+│                          1 │
+└────────────────────────────┘
+```
+
+## toUUID (x) {#touuid-x}
+
+Converts String type value to UUID type.
+
+``` sql
+toUUID(String)
+```
+
+**Returned value**
+
+The UUID type value.
+
+**Usage example**
+
+``` sql
+SELECT toUUID('61f0c404-5cb3-11e7-907b-a6006ad3dba0') AS uuid
+```
+
+``` text
+┌─────────────────────────────────uuid─┐
+│ 61f0c404-5cb3-11e7-907b-a6006ad3dba0 │
+└──────────────────────────────────────┘
+```
+
+## toUUIDOrNull (x) {#touuidornull-x}
+
+It takes an argument of type String and tries to parse it into UUID. If failed, returns NULL.
+
+``` sql
+toUUIDOrNull(String)
+```
+
+**Returned value**
+
+The Nullable(UUID) type value.
+
+**Usage example**
+
+``` sql
+SELECT toUUIDOrNull('61f0c404-5cb3-11e7-907b-a6006ad3dba0T') AS uuid
+```
+
+``` text
+┌─uuid─┐
+│ ᴺᵁᴸᴸ │
+└──────┘
+```
+
+## toUUIDOrZero (x) {#touuidorzero-x}
+
+It takes an argument of type String and tries to parse it into UUID. If failed, returns zero UUID.
+
+``` sql
+toUUIDOrZero(String)
+```
+
+**Returned value**
+
+The UUID type value.
+
+**Usage example**
+
+``` sql
+SELECT toUUIDOrZero('61f0c404-5cb3-11e7-907b-a6006ad3dba0T') AS uuid
+```
+
+``` text
+┌─────────────────────────────────uuid─┐
+│ 00000000-0000-0000-0000-000000000000 │
+└──────────────────────────────────────┘
+```
+
+## UUIDStringToNum {#uuidstringtonum}
+
+Accepts a string containing 36 characters in the format `xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`, and returns it as a set of bytes in a [FixedString(16)](../../sql-reference/data-types/fixedstring.md).
+
+``` sql
+UUIDStringToNum(String)
+```
+
+**Returned value**
+
+FixedString(16)
+
+**Usage examples**
+
+``` sql
+SELECT
+    '612f3c40-5d3b-217e-707b-6a546a3d7b29' AS uuid,
+    UUIDStringToNum(uuid) AS bytes
+```
+
+``` text
+┌─uuid─────────────────────────────────┬─bytes────────────┐
+│ 612f3c40-5d3b-217e-707b-6a546a3d7b29 │ a/<@];!~p{jTj={) │
+└──────────────────────────────────────┴──────────────────┘
+```
+
+## UUIDNumToString {#uuidnumtostring}
+
+Accepts a [FixedString(16)](../../sql-reference/data-types/fixedstring.md) value, and returns a string containing 36 characters in text format.
+
+``` sql
+UUIDNumToString(FixedString(16))
+```
+
+**Returned value**
+
+String.
+
+**Usage example**
+
+``` sql
+SELECT
+    'a/<@];!~p{jTj={)' AS bytes,
+    UUIDNumToString(toFixedString(bytes, 16)) AS uuid
+```
+
+``` text
+┌─bytes────────────┬─uuid─────────────────────────────────┐
+│ a/<@];!~p{jTj={) │ 612f3c40-5d3b-217e-707b-6a546a3d7b29 │
+└──────────────────┴──────────────────────────────────────┘
+```
+
+## serverUUID() {#server-uuid}
+
+Returns the random and unique UUID, which is generated when the server is first started and stored forever. The result writes to the file `uuid` created in the ClickHouse server directory `/var/lib/clickhouse/`. 
+
+**Syntax**
+
+```sql
+serverUUID()
+```
+
+**Returned value**
+
+-   The UUID of the server. 
+
+Type: [UUID](../data-types/uuid.md).
+
+## See Also {#see-also}
+
+-   [dictGetUUID](../../sql-reference/functions/ext-dict-functions.md#ext_dict_functions-other)
diff --git a/docs/en/reference/sql-reference/functions/ym-dict-functions.md b/docs/en/reference/sql-reference/functions/ym-dict-functions.md
new file mode 100644
index 00000000000..85215957443
--- /dev/null
+++ b/docs/en/reference/sql-reference/functions/ym-dict-functions.md
@@ -0,0 +1,152 @@
+---
+sidebar_position: 59
+sidebar_label: Embedded Dictionaries
+---
+
+# Functions for Working with Embedded Dictionaries
+
+In order for the functions below to work, the server config must specify the paths and addresses for getting all the embedded dictionaries. The dictionaries are loaded at the first call of any of these functions. If the reference lists can’t be loaded, an exception is thrown.
+
+For information about creating reference lists, see the section “Dictionaries”.
+
+## Multiple Geobases {#multiple-geobases}
+
+ClickHouse supports working with multiple alternative geobases (regional hierarchies) simultaneously, in order to support various perspectives on which countries certain regions belong to.
+
+The ‘clickhouse-server’ config specifies the file with the regional hierarchy::`<path_to_regions_hierarchy_file>/opt/geo/regions_hierarchy.txt</path_to_regions_hierarchy_file>`
+
+Besides this file, it also searches for files nearby that have the _ symbol and any suffix appended to the name (before the file extension).
+For example, it will also find the file `/opt/geo/regions_hierarchy_ua.txt`, if present.
+
+`ua` is called the dictionary key. For a dictionary without a suffix, the key is an empty string.
+
+All the dictionaries are re-loaded in runtime (once every certain number of seconds, as defined in the builtin_dictionaries_reload_interval config parameter, or once an hour by default). However, the list of available dictionaries is defined one time, when the server starts.
+
+All functions for working with regions have an optional argument at the end – the dictionary key. It is referred to as the geobase.
+Example:
+
+``` sql
+regionToCountry(RegionID) – Uses the default dictionary: /opt/geo/regions_hierarchy.txt
+regionToCountry(RegionID, '') – Uses the default dictionary: /opt/geo/regions_hierarchy.txt
+regionToCountry(RegionID, 'ua') – Uses the dictionary for the 'ua' key: /opt/geo/regions_hierarchy_ua.txt
+```
+
+### regionToCity(id\[, geobase\]) {#regiontocityid-geobase}
+
+Accepts a UInt32 number – the region ID from the geobase. If this region is a city or part of a city, it returns the region ID for the appropriate city. Otherwise, returns 0.
+
+### regionToArea(id\[, geobase\]) {#regiontoareaid-geobase}
+
+Converts a region to an area (type 5 in the geobase). In every other way, this function is the same as ‘regionToCity’.
+
+``` sql
+SELECT DISTINCT regionToName(regionToArea(toUInt32(number), 'ua'))
+FROM system.numbers
+LIMIT 15
+```
+
+``` text
+┌─regionToName(regionToArea(toUInt32(number), \'ua\'))─┐
+│                                                      │
+│ Moscow and Moscow region                             │
+│ St. Petersburg and Leningrad region                  │
+│ Belgorod region                                      │
+│ Ivanovsk region                                      │
+│ Kaluga region                                        │
+│ Kostroma region                                      │
+│ Kursk region                                         │
+│ Lipetsk region                                       │
+│ Orlov region                                         │
+│ Ryazan region                                        │
+│ Smolensk region                                      │
+│ Tambov region                                        │
+│ Tver region                                          │
+│ Tula region                                          │
+└──────────────────────────────────────────────────────┘
+```
+
+### regionToDistrict(id\[, geobase\]) {#regiontodistrictid-geobase}
+
+Converts a region to a federal district (type 4 in the geobase). In every other way, this function is the same as ‘regionToCity’.
+
+``` sql
+SELECT DISTINCT regionToName(regionToDistrict(toUInt32(number), 'ua'))
+FROM system.numbers
+LIMIT 15
+```
+
+``` text
+┌─regionToName(regionToDistrict(toUInt32(number), \'ua\'))─┐
+│                                                          │
+│ Central federal district                                 │
+│ Northwest federal district                               │
+│ South federal district                                   │
+│ North Caucases federal district                          │
+│ Privolga federal district                                │
+│ Ural federal district                                    │
+│ Siberian federal district                                │
+│ Far East federal district                                │
+│ Scotland                                                 │
+│ Faroe Islands                                            │
+│ Flemish region                                           │
+│ Brussels capital region                                  │
+│ Wallonia                                                 │
+│ Federation of Bosnia and Herzegovina                     │
+└──────────────────────────────────────────────────────────┘
+```
+
+### regionToCountry(id\[, geobase\]) {#regiontocountryid-geobase}
+
+Converts a region to a country. In every other way, this function is the same as ‘regionToCity’.
+Example: `regionToCountry(toUInt32(213)) = 225` converts Moscow (213) to Russia (225).
+
+### regionToContinent(id\[, geobase\]) {#regiontocontinentid-geobase}
+
+Converts a region to a continent. In every other way, this function is the same as ‘regionToCity’.
+Example: `regionToContinent(toUInt32(213)) = 10001` converts Moscow (213) to Eurasia (10001).
+
+### regionToTopContinent (#regiontotopcontinent) {#regiontotopcontinent-regiontotopcontinent}
+
+Finds the highest continent in the hierarchy for the region.
+
+**Syntax**
+
+``` sql
+regionToTopContinent(id[, geobase])
+```
+
+**Arguments**
+
+-   `id` — Region ID from the geobase. [UInt32](../../sql-reference/data-types/int-uint.md).
+-   `geobase` — Dictionary key. See [Multiple Geobases](#multiple-geobases). [String](../../sql-reference/data-types/string.md). Optional.
+
+**Returned value**
+
+-   Identifier of the top level continent (the latter when you climb the hierarchy of regions).
+-   0, if there is none.
+
+Type: `UInt32`.
+
+### regionToPopulation(id\[, geobase\]) {#regiontopopulationid-geobase}
+
+Gets the population for a region.
+The population can be recorded in files with the geobase. See the section “External dictionaries”.
+If the population is not recorded for the region, it returns 0.
+In the geobase, the population might be recorded for child regions, but not for parent regions.
+
+### regionIn(lhs, rhs\[, geobase\]) {#regioninlhs-rhs-geobase}
+
+Checks whether a ‘lhs’ region belongs to a ‘rhs’ region. Returns a UInt8 number equal to 1 if it belongs, or 0 if it does not belong.
+The relationship is reflexive – any region also belongs to itself.
+
+### regionHierarchy(id\[, geobase\]) {#regionhierarchyid-geobase}
+
+Accepts a UInt32 number – the region ID from the geobase. Returns an array of region IDs consisting of the passed region and all parents along the chain.
+Example: `regionHierarchy(toUInt32(213)) = [213,1,3,225,10001,10000]`.
+
+### regionToName(id\[, lang\]) {#regiontonameid-lang}
+
+Accepts a UInt32 number – the region ID from the geobase. A string with the name of the language can be passed as a second argument. Supported languages are: ru, en, ua, uk, by, kz, tr. If the second argument is omitted, the language ‘ru’ is used. If the language is not supported, an exception is thrown. Returns a string – the name of the region in the corresponding language. If the region with the specified ID does not exist, an empty string is returned.
+
+`ua` and `uk` both mean Ukrainian.
+
diff --git a/docs/en/reference/sql-reference/index.md b/docs/en/reference/sql-reference/index.md
new file mode 100644
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--- /dev/null
+++ b/docs/en/reference/sql-reference/index.md
@@ -0,0 +1,16 @@
+---
+sidebar_position: 28
+sidebar_label: SQL Reference
+---
+
+# SQL Reference {#sql-reference}
+
+ClickHouse supports the following types of queries:
+
+-   [SELECT](../sql-reference/statements/select/index.md)
+-   [INSERT INTO](../sql-reference/statements/insert-into.md)
+-   [CREATE](../sql-reference/statements/create/index.md)
+-   [ALTER](../sql-reference/statements/alter/index.md)
+-   [Other types of queries](../sql-reference/statements/index.md)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/operators/exists.md b/docs/en/reference/sql-reference/operators/exists.md
new file mode 100644
index 00000000000..25413790801
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+++ b/docs/en/reference/sql-reference/operators/exists.md
@@ -0,0 +1,45 @@
+# EXISTS {#exists-operator}
+
+The `EXISTS` operator checks how many records are in the result of a subquery. If it is empty, then the operator returns `0`. Otherwise, it returns `1`.
+
+`EXISTS` can be used in a [WHERE](../../sql-reference/statements/select/where.md) clause.
+
+:::warning    
+References to main query tables and columns are not supported in a subquery.
+:::
+
+**Syntax**
+
+```sql
+WHERE EXISTS(subquery)
+```
+
+**Example**
+
+Query with a subquery returning several rows:
+
+``` sql
+SELECT count() FROM numbers(10) WHERE EXISTS(SELECT number FROM numbers(10) WHERE number > 8);
+```
+
+Result:
+
+``` text
+┌─count()─┐
+│      10 │
+└─────────┘
+```
+
+Query with a subquery that returns an empty result:
+
+``` sql
+SELECT count() FROM numbers(10) WHERE EXISTS(SELECT number FROM numbers(10) WHERE number > 11);
+```
+
+Result:
+
+``` text
+┌─count()─┐
+│       0 │
+└─────────┘
+```
diff --git a/docs/en/reference/sql-reference/operators/in.md b/docs/en/reference/sql-reference/operators/in.md
new file mode 100644
index 00000000000..5dda097e799
--- /dev/null
+++ b/docs/en/reference/sql-reference/operators/in.md
@@ -0,0 +1,251 @@
+# IN Operators {#select-in-operators}
+
+The `IN`, `NOT IN`, `GLOBAL IN`, and `GLOBAL NOT IN` operators are covered separately, since their functionality is quite rich.
+
+The left side of the operator is either a single column or a tuple.
+
+Examples:
+
+``` sql
+SELECT UserID IN (123, 456) FROM ...
+SELECT (CounterID, UserID) IN ((34, 123), (101500, 456)) FROM ...
+```
+
+If the left side is a single column that is in the index, and the right side is a set of constants, the system uses the index for processing the query.
+
+Don’t list too many values explicitly (i.e. millions). If a data set is large, put it in a temporary table (for example, see the section [External data for query processing](../../engines/table-engines/special/external-data.md)), then use a subquery.
+
+The right side of the operator can be a set of constant expressions, a set of tuples with constant expressions (shown in the examples above), or the name of a database table or SELECT subquery in brackets.
+
+ClickHouse allows types to differ in the left and the right parts of `IN` subquery. In this case it converts the left side value to the type of the right side, as if the [accurateCastOrNull](../functions/type-conversion-functions.md#type_conversion_function-accurate-cast_or_null) function is applied. That means, that the data type becomes [Nullable](../../sql-reference/data-types/nullable.md), and if the conversion cannot be performed, it returns [NULL](../../sql-reference/syntax.md#null-literal).
+
+**Example**
+
+Query:
+
+``` sql
+SELECT '1' IN (SELECT 1);
+```
+
+Result:
+
+``` text
+┌─in('1', _subquery49)─┐
+│                    1 │
+└──────────────────────┘
+```
+
+If the right side of the operator is the name of a table (for example, `UserID IN users`), this is equivalent to the subquery `UserID IN (SELECT * FROM users)`. Use this when working with external data that is sent along with the query. For example, the query can be sent together with a set of user IDs loaded to the ‘users’ temporary table, which should be filtered.
+
+If the right side of the operator is a table name that has the Set engine (a prepared data set that is always in RAM), the data set will not be created over again for each query.
+
+The subquery may specify more than one column for filtering tuples.
+Example:
+
+``` sql
+SELECT (CounterID, UserID) IN (SELECT CounterID, UserID FROM ...) FROM ...
+```
+
+The columns to the left and right of the IN operator should have the same type.
+
+The IN operator and subquery may occur in any part of the query, including in aggregate functions and lambda functions.
+Example:
+
+``` sql
+SELECT
+    EventDate,
+    avg(UserID IN
+    (
+        SELECT UserID
+        FROM test.hits
+        WHERE EventDate = toDate('2014-03-17')
+    )) AS ratio
+FROM test.hits
+GROUP BY EventDate
+ORDER BY EventDate ASC
+```
+
+``` text
+┌──EventDate─┬────ratio─┐
+│ 2014-03-17 │        1 │
+│ 2014-03-18 │ 0.807696 │
+│ 2014-03-19 │ 0.755406 │
+│ 2014-03-20 │ 0.723218 │
+│ 2014-03-21 │ 0.697021 │
+│ 2014-03-22 │ 0.647851 │
+│ 2014-03-23 │ 0.648416 │
+└────────────┴──────────┘
+```
+
+For each day after March 17th, count the percentage of pageviews made by users who visited the site on March 17th.
+A subquery in the IN clause is always run just one time on a single server. There are no dependent subqueries.
+
+## NULL Processing {#in-null-processing}
+
+During request processing, the `IN` operator assumes that the result of an operation with [NULL](../../sql-reference/syntax.md#null-literal) always equals `0`, regardless of whether `NULL` is on the right or left side of the operator. `NULL` values are not included in any dataset, do not correspond to each other and cannot be compared if [transform_null_in = 0](../../operations/settings/settings.md#transform_null_in).
+
+Here is an example with the `t_null` table:
+
+``` text
+┌─x─┬────y─┐
+│ 1 │ ᴺᵁᴸᴸ │
+│ 2 │    3 │
+└───┴──────┘
+```
+
+Running the query `SELECT x FROM t_null WHERE y IN (NULL,3)` gives you the following result:
+
+``` text
+┌─x─┐
+│ 2 │
+└───┘
+```
+
+You can see that the row in which `y = NULL` is thrown out of the query results. This is because ClickHouse can’t decide whether `NULL` is included in the `(NULL,3)` set, returns `0` as the result of the operation, and `SELECT` excludes this row from the final output.
+
+``` sql
+SELECT y IN (NULL, 3)
+FROM t_null
+```
+
+``` text
+┌─in(y, tuple(NULL, 3))─┐
+│                     0 │
+│                     1 │
+└───────────────────────┘
+```
+
+## Distributed Subqueries {#select-distributed-subqueries}
+
+There are two options for IN-s with subqueries (similar to JOINs): normal `IN` / `JOIN` and `GLOBAL IN` / `GLOBAL JOIN`. They differ in how they are run for distributed query processing.
+
+:::note    
+Remember that the algorithms described below may work differently depending on the [settings](../../operations/settings/settings.md) `distributed_product_mode` setting.
+:::
+
+When using the regular IN, the query is sent to remote servers, and each of them runs the subqueries in the `IN` or `JOIN` clause.
+
+When using `GLOBAL IN` / `GLOBAL JOINs`, first all the subqueries are run for `GLOBAL IN` / `GLOBAL JOINs`, and the results are collected in temporary tables. Then the temporary tables are sent to each remote server, where the queries are run using this temporary data.
+
+For a non-distributed query, use the regular `IN` / `JOIN`.
+
+Be careful when using subqueries in the `IN` / `JOIN` clauses for distributed query processing.
+
+Let’s look at some examples. Assume that each server in the cluster has a normal **local_table**. Each server also has a **distributed_table** table with the **Distributed** type, which looks at all the servers in the cluster.
+
+For a query to the **distributed_table**, the query will be sent to all the remote servers and run on them using the **local_table**.
+
+For example, the query
+
+``` sql
+SELECT uniq(UserID) FROM distributed_table
+```
+
+will be sent to all remote servers as
+
+``` sql
+SELECT uniq(UserID) FROM local_table
+```
+
+and run on each of them in parallel, until it reaches the stage where intermediate results can be combined. Then the intermediate results will be returned to the requestor server and merged on it, and the final result will be sent to the client.
+
+Now let’s examine a query with IN:
+
+``` sql
+SELECT uniq(UserID) FROM distributed_table WHERE CounterID = 101500 AND UserID IN (SELECT UserID FROM local_table WHERE CounterID = 34)
+```
+
+-   Calculation of the intersection of audiences of two sites.
+
+This query will be sent to all remote servers as
+
+``` sql
+SELECT uniq(UserID) FROM local_table WHERE CounterID = 101500 AND UserID IN (SELECT UserID FROM local_table WHERE CounterID = 34)
+```
+
+In other words, the data set in the IN clause will be collected on each server independently, only across the data that is stored locally on each of the servers.
+
+This will work correctly and optimally if you are prepared for this case and have spread data across the cluster servers such that the data for a single UserID resides entirely on a single server. In this case, all the necessary data will be available locally on each server. Otherwise, the result will be inaccurate. We refer to this variation of the query as “local IN”.
+
+To correct how the query works when data is spread randomly across the cluster servers, you could specify **distributed_table** inside a subquery. The query would look like this:
+
+``` sql
+SELECT uniq(UserID) FROM distributed_table WHERE CounterID = 101500 AND UserID IN (SELECT UserID FROM distributed_table WHERE CounterID = 34)
+```
+
+This query will be sent to all remote servers as
+
+``` sql
+SELECT uniq(UserID) FROM local_table WHERE CounterID = 101500 AND UserID IN (SELECT UserID FROM distributed_table WHERE CounterID = 34)
+```
+
+The subquery will begin running on each remote server. Since the subquery uses a distributed table, the subquery that is on each remote server will be resent to every remote server as
+
+``` sql
+SELECT UserID FROM local_table WHERE CounterID = 34
+```
+
+For example, if you have a cluster of 100 servers, executing the entire query will require 10,000 elementary requests, which is generally considered unacceptable.
+
+In such cases, you should always use GLOBAL IN instead of IN. Let’s look at how it works for the query
+
+``` sql
+SELECT uniq(UserID) FROM distributed_table WHERE CounterID = 101500 AND UserID GLOBAL IN (SELECT UserID FROM distributed_table WHERE CounterID = 34)
+```
+
+The requestor server will run the subquery
+
+``` sql
+SELECT UserID FROM distributed_table WHERE CounterID = 34
+```
+
+and the result will be put in a temporary table in RAM. Then the request will be sent to each remote server as
+
+``` sql
+SELECT uniq(UserID) FROM local_table WHERE CounterID = 101500 AND UserID GLOBAL IN _data1
+```
+
+and the temporary table `_data1` will be sent to every remote server with the query (the name of the temporary table is implementation-defined).
+
+This is more optimal than using the normal IN. However, keep the following points in mind:
+
+1.  When creating a temporary table, data is not made unique. To reduce the volume of data transmitted over the network, specify DISTINCT in the subquery. (You do not need to do this for a normal IN.)
+2.  The temporary table will be sent to all the remote servers. Transmission does not account for network topology. For example, if 10 remote servers reside in a datacenter that is very remote in relation to the requestor server, the data will be sent 10 times over the channel to the remote datacenter. Try to avoid large data sets when using GLOBAL IN.
+3.  When transmitting data to remote servers, restrictions on network bandwidth are not configurable. You might overload the network.
+4.  Try to distribute data across servers so that you do not need to use GLOBAL IN on a regular basis.
+5.  If you need to use GLOBAL IN often, plan the location of the ClickHouse cluster so that a single group of replicas resides in no more than one data center with a fast network between them, so that a query can be processed entirely within a single data center.
+
+It also makes sense to specify a local table in the `GLOBAL IN` clause, in case this local table is only available on the requestor server and you want to use data from it on remote servers.
+
+### Distributed Subqueries and max_rows_in_set
+
+You can use [`max_rows_in_set`](../../operations/settings/query-complexity.md#max-rows-in-set) and [`max_bytes_in_set`](../../operations/settings/query-complexity.md#max-rows-in-set) to control how much data is tranferred during distributed queries. 
+
+This is specially important if the  `global in` query returns a large amount of data. Consider the following sql - 
+```sql
+select * from table1 where col1 global in (select col1 from table2 where <some_predicate>)
+```
+ 
+If `some_predicate` is not selective enough, it will return large amount of data and cause performance issues. In such cases, it is wise to limit the data transfer over the network. Also, note that [`set_overflow_mode`](../../operations/settings/query-complexity.md#set_overflow_mode) is set to `throw` (by default) meaning that an exception is raised when these thresholds are met.
+
+### Distributed Subqueries and max_parallel_replicas {#max_parallel_replica-subqueries}
+
+When max_parallel_replicas is greater than 1, distributed queries are further transformed. For example, the following:
+
+```sql
+SELECT CounterID, count() FROM distributed_table_1 WHERE UserID IN (SELECT UserID FROM local_table_2 WHERE CounterID < 100)
+SETTINGS max_parallel_replicas=3
+```
+
+is transformed on each server into
+
+```sql
+SELECT CounterID, count() FROM local_table_1 WHERE UserID IN (SELECT UserID FROM local_table_2 WHERE CounterID < 100)
+SETTINGS parallel_replicas_count=3, parallel_replicas_offset=M
+```
+
+where M is between 1 and 3 depending on which replica the local query is executing on. These settings affect every MergeTree-family table in the query and have the same effect as applying `SAMPLE 1/3 OFFSET (M-1)/3` on each table.
+
+Therefore adding the max_parallel_replicas setting will only produce correct results if both tables have the same replication scheme and are sampled by UserID or a subkey of it. In particular, if local_table_2 does not have a sampling key, incorrect results will be produced. The same rule applies to JOIN.
+
+One workaround if local_table_2 does not meet the requirements, is to use `GLOBAL IN` or `GLOBAL JOIN`.
diff --git a/docs/en/reference/sql-reference/operators/index.md b/docs/en/reference/sql-reference/operators/index.md
new file mode 100644
index 00000000000..4761f46ec05
--- /dev/null
+++ b/docs/en/reference/sql-reference/operators/index.md
@@ -0,0 +1,377 @@
+---
+sidebar_position: 38
+sidebar_label: Operators
+---
+
+# Operators {#operators}
+
+ClickHouse transforms operators to their corresponding functions at the query parsing stage according to their priority, precedence, and associativity.
+
+## Access Operators {#access-operators}
+
+`a[N]` – Access to an element of an array. The `arrayElement(a, N)` function.
+
+`a.N` – Access to a tuple element. The `tupleElement(a, N)` function.
+
+## Numeric Negation Operator {#numeric-negation-operator}
+
+`-a` – The `negate (a)` function.
+
+For tuple negation: [tupleNegate](../../sql-reference/functions/tuple-functions.md#tuplenegate).
+
+## Multiplication and Division Operators {#multiplication-and-division-operators}
+
+`a * b` – The `multiply (a, b)` function.
+
+For multiplying tuple by number: [tupleMultiplyByNumber](../../sql-reference/functions/tuple-functions.md#tuplemultiplybynumber), for scalar profuct: [dotProduct](../../sql-reference/functions/tuple-functions.md#dotproduct).
+
+`a / b` – The `divide(a, b)` function.
+
+For dividing tuple by number: [tupleDivideByNumber](../../sql-reference/functions/tuple-functions.md#tupledividebynumber).
+
+`a % b` – The `modulo(a, b)` function.
+
+## Addition and Subtraction Operators {#addition-and-subtraction-operators}
+
+`a + b` – The `plus(a, b)` function.
+
+For tuple addiction: [tuplePlus](../../sql-reference/functions/tuple-functions.md#tupleplus).
+
+`a - b` – The `minus(a, b)` function.
+
+For tuple subtraction: [tupleMinus](../../sql-reference/functions/tuple-functions.md#tupleminus).
+
+## Comparison Operators {#comparison-operators}
+
+`a = b` – The `equals(a, b)` function.
+
+`a == b` – The `equals(a, b)` function.
+
+`a != b` – The `notEquals(a, b)` function.
+
+`a <> b` – The `notEquals(a, b)` function.
+
+`a <= b` – The `lessOrEquals(a, b)` function.
+
+`a >= b` – The `greaterOrEquals(a, b)` function.
+
+`a < b` – The `less(a, b)` function.
+
+`a > b` – The `greater(a, b)` function.
+
+`a LIKE s` – The `like(a, b)` function.
+
+`a NOT LIKE s` – The `notLike(a, b)` function.
+
+`a ILIKE s` – The `ilike(a, b)` function.
+
+`a BETWEEN b AND c` – The same as `a >= b AND a <= c`.
+
+`a NOT BETWEEN b AND c` – The same as `a < b OR a > c`.
+
+## Operators for Working with Data Sets {#operators-for-working-with-data-sets}
+
+See [IN operators](../../sql-reference/operators/in.md) and [EXISTS](../../sql-reference/operators/exists.md) operator.
+
+`a IN ...` – The `in(a, b)` function.
+
+`a NOT IN ...` – The `notIn(a, b)` function.
+
+`a GLOBAL IN ...` – The `globalIn(a, b)` function.
+
+`a GLOBAL NOT IN ...` – The `globalNotIn(a, b)` function.
+
+`a = ANY (subquery)` – The `in(a, subquery)` function.  
+
+`a != ANY (subquery)` – The same as `a NOT IN (SELECT singleValueOrNull(*) FROM subquery)`.
+
+`a = ALL (subquery)` – The same as `a IN (SELECT singleValueOrNull(*) FROM subquery)`.
+
+`a != ALL (subquery)` – The `notIn(a, subquery)` function. 
+
+
+**Examples**
+
+Query with ALL:
+
+``` sql
+SELECT number AS a FROM numbers(10) WHERE a > ALL (SELECT number FROM numbers(3, 3));
+```
+
+Result:
+
+``` text
+┌─a─┐
+│ 6 │
+│ 7 │
+│ 8 │
+│ 9 │
+└───┘
+```
+
+Query with ANY:
+
+``` sql
+SELECT number AS a FROM numbers(10) WHERE a > ANY (SELECT number FROM numbers(3, 3));
+```
+
+Result:
+
+``` text
+┌─a─┐
+│ 4 │
+│ 5 │
+│ 6 │
+│ 7 │
+│ 8 │
+│ 9 │
+└───┘
+```
+
+## Operators for Working with Dates and Times {#operators-datetime}
+
+### EXTRACT {#operator-extract}
+
+``` sql
+EXTRACT(part FROM date);
+```
+
+Extract parts from a given date. For example, you can retrieve a month from a given date, or a second from a time.
+
+The `part` parameter specifies which part of the date to retrieve. The following values are available:
+
+-   `DAY` — The day of the month. Possible values: 1–31.
+-   `MONTH` — The number of a month. Possible values: 1–12.
+-   `YEAR` — The year.
+-   `SECOND` — The second. Possible values: 0–59.
+-   `MINUTE` — The minute. Possible values: 0–59.
+-   `HOUR` — The hour. Possible values: 0–23.
+
+The `part` parameter is case-insensitive.
+
+The `date` parameter specifies the date or the time to process. Either [Date](../../sql-reference/data-types/date.md) or [DateTime](../../sql-reference/data-types/datetime.md) type is supported.
+
+Examples:
+
+``` sql
+SELECT EXTRACT(DAY FROM toDate('2017-06-15'));
+SELECT EXTRACT(MONTH FROM toDate('2017-06-15'));
+SELECT EXTRACT(YEAR FROM toDate('2017-06-15'));
+```
+
+In the following example we create a table and insert into it a value with the `DateTime` type.
+
+``` sql
+CREATE TABLE test.Orders
+(
+    OrderId UInt64,
+    OrderName String,
+    OrderDate DateTime
+)
+ENGINE = Log;
+```
+
+``` sql
+INSERT INTO test.Orders VALUES (1, 'Jarlsberg Cheese', toDateTime('2008-10-11 13:23:44'));
+```
+
+``` sql
+SELECT
+    toYear(OrderDate) AS OrderYear,
+    toMonth(OrderDate) AS OrderMonth,
+    toDayOfMonth(OrderDate) AS OrderDay,
+    toHour(OrderDate) AS OrderHour,
+    toMinute(OrderDate) AS OrderMinute,
+    toSecond(OrderDate) AS OrderSecond
+FROM test.Orders;
+```
+
+``` text
+┌─OrderYear─┬─OrderMonth─┬─OrderDay─┬─OrderHour─┬─OrderMinute─┬─OrderSecond─┐
+│      2008 │         10 │       11 │        13 │          23 │          44 │
+└───────────┴────────────┴──────────┴───────────┴─────────────┴─────────────┘
+```
+
+You can see more examples in [tests](https://github.com/ClickHouse/ClickHouse/blob/master/tests/queries/0_stateless/00619_extract.sql).
+
+### INTERVAL {#operator-interval}
+
+Creates an [Interval](../../sql-reference/data-types/special-data-types/interval.md)-type value that should be used in arithmetical operations with [Date](../../sql-reference/data-types/date.md) and [DateTime](../../sql-reference/data-types/datetime.md)-type values.
+
+Types of intervals:
+- `SECOND`
+- `MINUTE`
+- `HOUR`
+- `DAY`
+- `WEEK`
+- `MONTH`
+- `QUARTER`
+- `YEAR`
+
+You can also use a string literal when setting the `INTERVAL` value. For example, `INTERVAL 1 HOUR` is identical to the `INTERVAL '1 hour'` or `INTERVAL '1' hour`.
+
+:::warning    
+Intervals with different types can’t be combined. You can’t use expressions like `INTERVAL 4 DAY 1 HOUR`. Specify intervals in units that are smaller or equal to the smallest unit of the interval, for example, `INTERVAL 25 HOUR`. You can use consecutive operations, like in the example below.
+:::
+
+Examples:
+
+``` sql
+SELECT now() AS current_date_time, current_date_time + INTERVAL 4 DAY + INTERVAL 3 HOUR;
+```
+
+``` text
+┌───current_date_time─┬─plus(plus(now(), toIntervalDay(4)), toIntervalHour(3))─┐
+│ 2020-11-03 22:09:50 │                                    2020-11-08 01:09:50 │
+└─────────────────────┴────────────────────────────────────────────────────────┘
+```
+
+``` sql
+SELECT now() AS current_date_time, current_date_time + INTERVAL '4 day' + INTERVAL '3 hour';
+```
+
+``` text
+┌───current_date_time─┬─plus(plus(now(), toIntervalDay(4)), toIntervalHour(3))─┐
+│ 2020-11-03 22:12:10 │                                    2020-11-08 01:12:10 │
+└─────────────────────┴────────────────────────────────────────────────────────┘
+```
+
+``` sql
+SELECT now() AS current_date_time, current_date_time + INTERVAL '4' day + INTERVAL '3' hour;
+```
+
+``` text
+┌───current_date_time─┬─plus(plus(now(), toIntervalDay('4')), toIntervalHour('3'))─┐
+│ 2020-11-03 22:33:19 │                                        2020-11-08 01:33:19 │
+└─────────────────────┴────────────────────────────────────────────────────────────┘
+```
+
+You can work with dates without using `INTERVAL`, just by adding or subtracting seconds, minutes, and hours. For example, an interval of one day can be set by adding `60*60*24`.
+
+:::note    
+The `INTERVAL` syntax or `addDays` function are always preferred. Simple addition or subtraction (syntax like `now() + ...`) doesn't consider time settings. For example, daylight saving time.
+:::
+
+Examples:
+
+``` sql
+SELECT toDateTime('2014-10-26 00:00:00', 'Asia/Istanbul') AS time, time + 60 * 60 * 24 AS time_plus_24_hours, time + toIntervalDay(1) AS time_plus_1_day;
+```
+
+``` text
+┌────────────────time─┬──time_plus_24_hours─┬─────time_plus_1_day─┐
+│ 2014-10-26 00:00:00 │ 2014-10-26 23:00:00 │ 2014-10-27 00:00:00 │
+└─────────────────────┴─────────────────────┴─────────────────────┘
+```
+
+**See Also**
+
+-   [Interval](../../sql-reference/data-types/special-data-types/interval.md) data type
+-   [toInterval](../../sql-reference/functions/type-conversion-functions.md#function-tointerval) type conversion functions
+
+## Logical AND Operator {#logical-and-operator}
+
+Syntax `SELECT a AND b` — calculates logical conjunction of `a` and `b` with the function [and](../../sql-reference/functions/logical-functions.md#logical-and-function).
+
+## Logical OR Operator {#logical-or-operator}
+
+Syntax `SELECT a OR b` — calculates logical disjunction of `a` and `b` with the function [or](../../sql-reference/functions/logical-functions.md#logical-or-function).
+
+## Logical Negation Operator {#logical-negation-operator}
+
+Syntax `SELECT NOT a` — calculates logical negation of `a` with the function [not](../../sql-reference/functions/logical-functions.md#logical-not-function).
+
+## Conditional Operator {#conditional-operator}
+
+`a ? b : c` – The `if(a, b, c)` function.
+
+Note:
+
+The conditional operator calculates the values of b and c, then checks whether condition a is met, and then returns the corresponding value. If `b` or `C` is an [arrayJoin()](../../sql-reference/functions/array-join.md#functions_arrayjoin) function, each row will be replicated regardless of the “a” condition.
+
+## Conditional Expression {#operator_case}
+
+``` sql
+CASE [x]
+    WHEN a THEN b
+    [WHEN ... THEN ...]
+    [ELSE c]
+END
+```
+
+If `x` is specified, then `transform(x, [a, ...], [b, ...], c)` function is used. Otherwise – `multiIf(a, b, ..., c)`.
+
+If there is no `ELSE c` clause in the expression, the default value is `NULL`.
+
+The `transform` function does not work with `NULL`.
+
+## Concatenation Operator {#concatenation-operator}
+
+`s1 || s2` – The `concat(s1, s2) function.`
+
+## Lambda Creation Operator {#lambda-creation-operator}
+
+`x -> expr` – The `lambda(x, expr) function.`
+
+The following operators do not have a priority since they are brackets:
+
+## Array Creation Operator {#array-creation-operator}
+
+`[x1, ...]` – The `array(x1, ...) function.`
+
+## Tuple Creation Operator {#tuple-creation-operator}
+
+`(x1, x2, ...)` – The `tuple(x2, x2, ...) function.`
+
+## Associativity {#associativity}
+
+All binary operators have left associativity. For example, `1 + 2 + 3` is transformed to `plus(plus(1, 2), 3)`.
+Sometimes this does not work the way you expect. For example, `SELECT 4 > 2 > 3` will result in 0.
+
+For efficiency, the `and` and `or` functions accept any number of arguments. The corresponding chains of `AND` and `OR` operators are transformed into a single call of these functions.
+
+## Checking for `NULL` {#checking-for-null}
+
+ClickHouse supports the `IS NULL` and `IS NOT NULL` operators.
+
+### IS NULL {#operator-is-null}
+
+-   For [Nullable](../../sql-reference/data-types/nullable.md) type values, the `IS NULL` operator returns:
+    -   `1`, if the value is `NULL`.
+    -   `0` otherwise.
+-   For other values, the `IS NULL` operator always returns `0`.
+
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn instead of reading and processing the whole column data. The query `SELECT n IS NULL FROM table` transforms to `SELECT n.null FROM TABLE`.
+
+<!-- -->
+
+``` sql
+SELECT x+100 FROM t_null WHERE y IS NULL
+```
+
+``` text
+┌─plus(x, 100)─┐
+│          101 │
+└──────────────┘
+```
+
+### IS NOT NULL {#is-not-null}
+
+-   For [Nullable](../../sql-reference/data-types/nullable.md) type values, the `IS NOT NULL` operator returns:
+    -   `0`, if the value is `NULL`.
+    -   `1` otherwise.
+-   For other values, the `IS NOT NULL` operator always returns `1`.
+
+<!-- -->
+
+``` sql
+SELECT * FROM t_null WHERE y IS NOT NULL
+```
+
+``` text
+┌─x─┬─y─┐
+│ 2 │ 3 │
+└───┴───┘
+```
+
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn instead of reading and processing the whole column data. The query `SELECT n IS NOT NULL FROM table` transforms to `SELECT NOT n.null FROM TABLE`.
diff --git a/docs/en/reference/sql-reference/statements/alter/column.md b/docs/en/reference/sql-reference/statements/alter/column.md
new file mode 100644
index 00000000000..3d22146a56b
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/column.md
@@ -0,0 +1,260 @@
+---
+sidebar_position: 37
+sidebar_label: COLUMN
+---
+
+# Column Manipulations {#column-manipulations}
+
+A set of queries that allow changing the table structure.
+
+Syntax:
+
+``` sql
+ALTER TABLE [db].name [ON CLUSTER cluster] ADD|DROP|RENAME|CLEAR|COMMENT|{MODIFY|ALTER}|MATERIALIZE COLUMN ...
+```
+
+In the query, specify a list of one or more comma-separated actions.
+Each action is an operation on a column.
+
+The following actions are supported:
+
+-   [ADD COLUMN](#alter_add-column) — Adds a new column to the table.
+-   [DROP COLUMN](#alter_drop-column) — Deletes the column.
+-   [RENAME COLUMN](#alter_rename-column) — Renames an existing column.
+-   [CLEAR COLUMN](#alter_clear-column) — Resets column values.
+-   [COMMENT COLUMN](#alter_comment-column) — Adds a text comment to the column.
+-   [MODIFY COLUMN](#alter_modify-column) — Changes column’s type, default expression and TTL.
+-   [MODIFY COLUMN REMOVE](#modify-remove) — Removes one of the column properties.
+-   [MATERIALIZE COLUMN](#materialize-column) — Materializes the column in the parts where the column is missing.
+
+These actions are described in detail below.
+
+## ADD COLUMN {#alter_add-column}
+
+``` sql
+ADD COLUMN [IF NOT EXISTS] name [type] [default_expr] [codec] [AFTER name_after | FIRST]
+```
+
+Adds a new column to the table with the specified `name`, `type`, [`codec`](../create/table.md#codecs) and `default_expr` (see the section [Default expressions](../../../sql-reference/statements/create/table.md#create-default-values)).
+
+If the `IF NOT EXISTS` clause is included, the query won’t return an error if the column already exists. If you specify `AFTER name_after` (the name of another column), the column is added after the specified one in the list of table columns. If you want to add a column to the beginning of the table use the `FIRST` clause. Otherwise, the column is added to the end of the table. For a chain of actions, `name_after` can be the name of a column that is added in one of the previous actions.
+
+Adding a column just changes the table structure, without performing any actions with data. The data does not appear on the disk after `ALTER`. If the data is missing for a column when reading from the table, it is filled in with default values (by performing the default expression if there is one, or using zeros or empty strings). The column appears on the disk after merging data parts (see [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md)).
+
+This approach allows us to complete the `ALTER` query instantly, without increasing the volume of old data.
+
+Example:
+
+``` sql
+ALTER TABLE alter_test ADD COLUMN Added1 UInt32 FIRST;
+ALTER TABLE alter_test ADD COLUMN Added2 UInt32 AFTER NestedColumn;
+ALTER TABLE alter_test ADD COLUMN Added3 UInt32 AFTER ToDrop;
+DESC alter_test FORMAT TSV;
+```
+
+``` text
+Added1  UInt32
+CounterID       UInt32
+StartDate       Date
+UserID  UInt32
+VisitID UInt32
+NestedColumn.A  Array(UInt8)
+NestedColumn.S  Array(String)
+Added2  UInt32
+ToDrop  UInt32
+Added3  UInt32
+```
+
+## DROP COLUMN {#alter_drop-column}
+
+``` sql
+DROP COLUMN [IF EXISTS] name
+```
+
+Deletes the column with the name `name`. If the `IF EXISTS` clause is specified, the query won’t return an error if the column does not exist.
+
+Deletes data from the file system. Since this deletes entire files, the query is completed almost instantly.
+
+:::warning    
+You can’t delete a column if it is referenced by [materialized view](../../../sql-reference/statements/create/view.md#materialized). Otherwise, it returns an error.
+:::
+
+Example:
+
+``` sql
+ALTER TABLE visits DROP COLUMN browser
+```
+
+## RENAME COLUMN {#alter_rename-column}
+
+``` sql
+RENAME COLUMN [IF EXISTS] name to new_name
+```
+
+Renames the column `name` to `new_name`. If the `IF EXISTS` clause is specified, the query won’t return an error if the column does not exist. Since renaming does not involve the underlying data, the query is completed almost instantly.
+
+**NOTE**: Columns specified in the key expression of the table (either with `ORDER BY` or `PRIMARY KEY`) cannot be renamed. Trying to change these columns will produce `SQL Error [524]`.
+
+Example:
+
+``` sql
+ALTER TABLE visits RENAME COLUMN webBrowser TO browser
+```
+
+## CLEAR COLUMN {#alter_clear-column}
+
+``` sql
+CLEAR COLUMN [IF EXISTS] name IN PARTITION partition_name
+```
+
+Resets all data in a column for a specified partition. Read more about setting the partition name in the section [How to specify the partition expression](#alter-how-to-specify-part-expr).
+
+If the `IF EXISTS` clause is specified, the query won’t return an error if the column does not exist.
+
+Example:
+
+``` sql
+ALTER TABLE visits CLEAR COLUMN browser IN PARTITION tuple()
+```
+
+## COMMENT COLUMN {#alter_comment-column}
+
+``` sql
+COMMENT COLUMN [IF EXISTS] name 'Text comment'
+```
+
+Adds a comment to the column. If the `IF EXISTS` clause is specified, the query won’t return an error if the column does not exist.
+
+Each column can have one comment. If a comment already exists for the column, a new comment overwrites the previous comment.
+
+Comments are stored in the `comment_expression` column returned by the [DESCRIBE TABLE](../../../sql-reference/statements/misc.md#misc-describe-table) query.
+
+Example:
+
+``` sql
+ALTER TABLE visits COMMENT COLUMN browser 'The table shows the browser used for accessing the site.'
+```
+
+## MODIFY COLUMN {#alter_modify-column}
+
+``` sql
+MODIFY COLUMN [IF EXISTS] name [type] [default_expr] [codec] [TTL] [AFTER name_after | FIRST]
+ALTER COLUMN [IF EXISTS] name TYPE [type] [default_expr] [codec] [TTL] [AFTER name_after | FIRST]
+```
+
+This query changes the `name` column properties:
+
+-   Type
+
+-   Default expression
+
+-   Compression Codec
+
+-   TTL
+
+For examples of columns compression CODECS modifying, see [Column Compression Codecs](../create/table.md#codecs).
+
+For examples of columns TTL modifying, see [Column TTL](../../../engines/table-engines/mergetree-family/mergetree.md#mergetree-column-ttl).
+
+If the `IF EXISTS` clause is specified, the query won’t return an error if the column does not exist.
+
+The query also can change the order of the columns using `FIRST | AFTER` clause, see [ADD COLUMN](#alter_add-column) description.
+
+When changing the type, values are converted as if the [toType](../../../sql-reference/functions/type-conversion-functions.md) functions were applied to them. If only the default expression is changed, the query does not do anything complex, and is completed almost instantly.
+
+Example:
+
+``` sql
+ALTER TABLE visits MODIFY COLUMN browser Array(String)
+```
+
+Changing the column type is the only complex action – it changes the contents of files with data. For large tables, this may take a long time.
+
+The `ALTER` query is atomic. For MergeTree tables it is also lock-free.
+
+The `ALTER` query for changing columns is replicated. The instructions are saved in ZooKeeper, then each replica applies them. All `ALTER` queries are run in the same order. The query waits for the appropriate actions to be completed on the other replicas. However, a query to change columns in a replicated table can be interrupted, and all actions will be performed asynchronously.
+
+## MODIFY COLUMN REMOVE {#modify-remove}
+
+Removes one of the column properties: `DEFAULT`, `ALIAS`, `MATERIALIZED`, `CODEC`, `COMMENT`, `TTL`.
+
+Syntax:
+
+```sql
+ALTER TABLE table_name MODIFY column_name REMOVE property;
+```
+
+**Example**
+
+Remove TTL:
+
+```sql
+ALTER TABLE table_with_ttl MODIFY COLUMN column_ttl REMOVE TTL;
+```
+
+**See Also**
+
+- [REMOVE TTL](ttl.md).
+
+## MATERIALIZE COLUMN {#materialize-column}
+
+Materializes or updates a column with an expression for a default value (`DEFAULT` or `MATERIALIZED`).
+It is used if it is necessary to add or update a column with a complicated expression, because evaluating such an expression directly on `SELECT` executing turns out to be expensive. 
+
+Syntax:
+
+```sql
+ALTER TABLE table MATERIALIZE COLUMN col;
+```
+
+**Example**
+
+```sql
+DROP TABLE IF EXISTS tmp;
+SET mutations_sync = 2;
+CREATE TABLE tmp (x Int64) ENGINE = MergeTree() ORDER BY tuple() PARTITION BY tuple();
+INSERT INTO tmp SELECT * FROM system.numbers LIMIT 5;
+ALTER TABLE tmp ADD COLUMN s String MATERIALIZED toString(x);
+
+ALTER TABLE tmp MATERIALIZE COLUMN s;
+
+SELECT groupArray(x), groupArray(s) FROM (select x,s from tmp order by x);
+
+┌─groupArray(x)─┬─groupArray(s)─────────┐
+│ [0,1,2,3,4]   │ ['0','1','2','3','4'] │
+└───────────────┴───────────────────────┘
+
+ALTER TABLE tmp MODIFY COLUMN s String MATERIALIZED toString(round(100/x));
+
+INSERT INTO tmp SELECT * FROM system.numbers LIMIT 5,5;
+
+SELECT groupArray(x), groupArray(s) FROM tmp;
+
+┌─groupArray(x)─────────┬─groupArray(s)──────────────────────────────────┐
+│ [0,1,2,3,4,5,6,7,8,9] │ ['0','1','2','3','4','20','17','14','12','11'] │
+└───────────────────────┴────────────────────────────────────────────────┘
+
+ALTER TABLE tmp MATERIALIZE COLUMN s;
+
+SELECT groupArray(x), groupArray(s) FROM tmp;
+
+┌─groupArray(x)─────────┬─groupArray(s)─────────────────────────────────────────┐
+│ [0,1,2,3,4,5,6,7,8,9] │ ['inf','100','50','33','25','20','17','14','12','11'] │
+└───────────────────────┴───────────────────────────────────────────────────────┘
+```
+
+**See Also**
+
+- [MATERIALIZED](../../statements/create/table.md#materialized).
+
+## Limitations {#alter-query-limitations}
+
+The `ALTER` query lets you create and delete separate elements (columns) in nested data structures, but not whole nested data structures. To add a nested data structure, you can add columns with a name like `name.nested_name` and the type `Array(T)`. A nested data structure is equivalent to multiple array columns with a name that has the same prefix before the dot.
+
+There is no support for deleting columns in the primary key or the sampling key (columns that are used in the `ENGINE` expression). Changing the type for columns that are included in the primary key is only possible if this change does not cause the data to be modified (for example, you are allowed to add values to an Enum or to change a type from `DateTime` to `UInt32`).
+
+If the `ALTER` query is not sufficient to make the table changes you need, you can create a new table, copy the data to it using the [INSERT SELECT](../../../sql-reference/statements/insert-into.md#insert_query_insert-select) query, then switch the tables using the [RENAME](../../../sql-reference/statements/misc.md#misc_operations-rename) query and delete the old table. You can use the [clickhouse-copier](../../../operations/utilities/clickhouse-copier.md) as an alternative to the `INSERT SELECT` query.
+
+The `ALTER` query blocks all reads and writes for the table. In other words, if a long `SELECT` is running at the time of the `ALTER` query, the `ALTER` query will wait for it to complete. At the same time, all new queries to the same table will wait while this `ALTER` is running.
+
+For tables that do not store data themselves (such as [Merge](../../../sql-reference/statements/alter/index.md) and [Distributed](../../../sql-reference/statements/alter/index.md)), `ALTER` just changes the table structure, and does not change the structure of subordinate tables. For example, when running ALTER for a `Distributed` table, you will also need to run `ALTER` for the tables on all remote servers.
diff --git a/docs/en/reference/sql-reference/statements/alter/comment.md b/docs/en/reference/sql-reference/statements/alter/comment.md
new file mode 100644
index 00000000000..af57adcf31c
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/comment.md
@@ -0,0 +1,58 @@
+---
+sidebar_position: 51
+sidebar_label: COMMENT
+---
+
+# ALTER TABLE … MODIFY COMMENT {#alter-modify-comment}
+
+Adds, modifies, or removes comment to the table, regardless if it was set before or not. Comment change is reflected in both [system.tables](../../../operations/system-tables/tables.md) and `SHOW CREATE TABLE` query.
+
+**Syntax**
+
+``` sql
+ALTER TABLE [db].name [ON CLUSTER cluster] MODIFY COMMENT 'Comment'
+```
+
+**Examples**
+
+Creating a table with comment (for more information, see the [COMMENT] clause(../../../sql-reference/statements/create/table.md#comment-table)):
+
+``` sql
+CREATE TABLE table_with_comment
+(
+    `k` UInt64,
+    `s` String
+)
+ENGINE = Memory()
+COMMENT 'The temporary table';
+```
+
+Modifying the table comment:
+
+``` sql
+ALTER TABLE table_with_comment MODIFY COMMENT 'new comment on a table';
+SELECT comment FROM system.tables WHERE database = currentDatabase() AND name = 'table_with_comment';
+```
+
+Output of a new comment:
+
+```text
+┌─comment────────────────┐
+│ new comment on a table │
+└────────────────────────┘
+```
+
+Removing the table comment:
+
+``` sql
+ALTER TABLE table_with_comment MODIFY COMMENT '';
+SELECT comment FROM system.tables WHERE database = currentDatabase() AND name = 'table_with_comment';
+```
+
+Output of a removed comment:
+
+```text
+┌─comment─┐
+│         │
+└─────────┘
+```
diff --git a/docs/en/reference/sql-reference/statements/alter/constraint.md b/docs/en/reference/sql-reference/statements/alter/constraint.md
new file mode 100644
index 00000000000..c9517981ae7
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/constraint.md
@@ -0,0 +1,23 @@
+---
+sidebar_position: 43
+sidebar_label: CONSTRAINT
+---
+
+# Manipulating Constraints {#manipulations-with-constraints}
+
+Constraints could be added or deleted using following syntax:
+
+``` sql
+ALTER TABLE [db].name ADD CONSTRAINT constraint_name CHECK expression;
+ALTER TABLE [db].name DROP CONSTRAINT constraint_name;
+```
+
+See more on [constraints](../../../sql-reference/statements/create/table.md#constraints).
+
+Queries will add or remove metadata about constraints from table so they are processed immediately.
+
+:::warning
+Constraint check **will not be executed** on existing data if it was added.
+:::
+
+All changes on replicated tables are broadcasted to ZooKeeper and will be applied on other replicas as well.
diff --git a/docs/en/reference/sql-reference/statements/alter/delete.md b/docs/en/reference/sql-reference/statements/alter/delete.md
new file mode 100644
index 00000000000..21ae091f9e7
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/delete.md
@@ -0,0 +1,28 @@
+---
+sidebar_position: 39
+sidebar_label: DELETE
+---
+
+# ALTER TABLE … DELETE Statement {#alter-mutations}
+
+``` sql
+ALTER TABLE [db.]table [ON CLUSTER cluster] DELETE WHERE filter_expr
+```
+
+Deletes data matching the specified filtering expression. Implemented as a [mutation](../../../sql-reference/statements/alter/index.md#mutations).
+
+:::note    
+The `ALTER TABLE` prefix makes this syntax different from most other systems supporting SQL. It is intended to signify that unlike similar queries in OLTP databases this is a heavy operation not designed for frequent use.
+:::
+
+The `filter_expr` must be of type `UInt8`. The query deletes rows in the table for which this expression takes a non-zero value.
+
+One query can contain several commands separated by commas.
+
+The synchronicity of the query processing is defined by the [mutations_sync](../../../operations/settings/settings.md#mutations_sync) setting. By default, it is asynchronous.
+
+**See also**
+
+-   [Mutations](../../../sql-reference/statements/alter/index.md#mutations)
+-   [Synchronicity of ALTER Queries](../../../sql-reference/statements/alter/index.md#synchronicity-of-alter-queries)
+-   [mutations_sync](../../../operations/settings/settings.md#mutations_sync) setting
diff --git a/docs/en/reference/sql-reference/statements/alter/index.md b/docs/en/reference/sql-reference/statements/alter/index.md
new file mode 100644
index 00000000000..536da948218
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/index.md
@@ -0,0 +1,62 @@
+---
+sidebar_position: 35
+sidebar_label: ALTER
+---
+
+# ALTER
+
+Most `ALTER TABLE` queries modify table settings or data:
+
+-   [COLUMN](../../../sql-reference/statements/alter/column.md)
+-   [PARTITION](../../../sql-reference/statements/alter/partition.md)
+-   [DELETE](../../../sql-reference/statements/alter/delete.md)
+-   [UPDATE](../../../sql-reference/statements/alter/update.md)
+-   [ORDER BY](../../../sql-reference/statements/alter/order-by.md)
+-   [INDEX](../../../sql-reference/statements/alter/index/index.md)
+-   [CONSTRAINT](../../../sql-reference/statements/alter/constraint.md)
+-   [TTL](../../../sql-reference/statements/alter/ttl.md)
+
+:::note    
+Most `ALTER TABLE` queries are supported only for [\*MergeTree](../../../engines/table-engines/mergetree-family/index.md) tables, as well as [Merge](../../../engines/table-engines/special/merge.md) and [Distributed](../../../engines/table-engines/special/distributed.md).
+:::
+
+These `ALTER` statements manipulate views:
+
+-   [ALTER TABLE ... MODIFY QUERY](../../../sql-reference/statements/alter/view.md) — Modifies a [Materialized view](../create/view.md#materialized) structure.
+-   [ALTER LIVE VIEW](../../../sql-reference/statements/alter/view.md#alter-live-view) — Refreshes a [Live view](../create/view.md#live-view).
+
+These `ALTER` statements modify entities related to role-based access control:
+
+-   [USER](../../../sql-reference/statements/alter/user.md)
+-   [ROLE](../../../sql-reference/statements/alter/role.md)
+-   [QUOTA](../../../sql-reference/statements/alter/quota.md)
+-   [ROW POLICY](../../../sql-reference/statements/alter/row-policy.md)
+-   [SETTINGS PROFILE](../../../sql-reference/statements/alter/settings-profile.md)
+
+[ALTER TABLE ... MODIFY COMMENT](../../../sql-reference/statements/alter/comment.md) statement adds, modifies, or removes comments to the table, regardless if it was set before or not.
+
+## Mutations {#mutations}
+
+`ALTER` queries that are intended to manipulate table data are implemented with a mechanism called “mutations”, most notably [ALTER TABLE … DELETE](../../../sql-reference/statements/alter/delete.md) and [ALTER TABLE … UPDATE](../../../sql-reference/statements/alter/update.md). They are asynchronous background processes similar to merges in [MergeTree](../../../engines/table-engines/mergetree-family/index.md) tables that to produce new “mutated” versions of parts.
+
+For `*MergeTree` tables mutations execute by **rewriting whole data parts**. There is no atomicity - parts are substituted for mutated parts as soon as they are ready and a `SELECT` query that started executing during a mutation will see data from parts that have already been mutated along with data from parts that have not been mutated yet.
+
+Mutations are totally ordered by their creation order and are applied to each part in that order. Mutations are also partially ordered with `INSERT INTO` queries: data that was inserted into the table before the mutation was submitted will be mutated and data that was inserted after that will not be mutated. Note that mutations do not block inserts in any way.
+
+A mutation query returns immediately after the mutation entry is added (in case of replicated tables to ZooKeeper, for non-replicated tables - to the filesystem). The mutation itself executes asynchronously using the system profile settings. To track the progress of mutations you can use the [`system.mutations`](../../../operations/system-tables/mutations.md#system_tables-mutations) table. A mutation that was successfully submitted will continue to execute even if ClickHouse servers are restarted. There is no way to roll back the mutation once it is submitted, but if the mutation is stuck for some reason it can be cancelled with the [`KILL MUTATION`](../../../sql-reference/statements/misc.md#kill-mutation) query.
+
+Entries for finished mutations are not deleted right away (the number of preserved entries is determined by the `finished_mutations_to_keep` storage engine parameter). Older mutation entries are deleted.
+
+## Synchronicity of ALTER Queries {#synchronicity-of-alter-queries}
+
+For non-replicated tables, all `ALTER` queries are performed synchronously. For replicated tables, the query just adds instructions for the appropriate actions to `ZooKeeper`, and the actions themselves are performed as soon as possible. However, the query can wait for these actions to be completed on all the replicas.
+
+For all `ALTER` queries, you can use the [replication_alter_partitions_sync](../../../operations/settings/settings.md#replication-alter-partitions-sync) setting to set up waiting.
+
+You can specify how long (in seconds) to wait for inactive replicas to execute all `ALTER` queries with the [replication_wait_for_inactive_replica_timeout](../../../operations/settings/settings.md#replication-wait-for-inactive-replica-timeout) setting.
+
+:::note    
+For all `ALTER` queries, if `replication_alter_partitions_sync = 2` and some replicas are not active for more than the time, specified in the `replication_wait_for_inactive_replica_timeout` setting, then an exception `UNFINISHED` is thrown.
+:::
+
+For `ALTER TABLE ... UPDATE|DELETE` queries the synchronicity is defined by the [mutations_sync](../../../operations/settings/settings.md#mutations_sync) setting.
diff --git a/docs/en/reference/sql-reference/statements/alter/index/index.md b/docs/en/reference/sql-reference/statements/alter/index/index.md
new file mode 100644
index 00000000000..92f55792a70
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/index/index.md
@@ -0,0 +1,23 @@
+---
+toc_hidden_folder: true
+sidebar_position: 42
+sidebar_label: INDEX
+---
+
+# Manipulating Data Skipping Indices {#manipulations-with-data-skipping-indices}
+
+The following operations are available:
+
+-   `ALTER TABLE [db].name ADD INDEX name expression TYPE type GRANULARITY value [FIRST|AFTER name]` - Adds index description to tables metadata.
+
+-   `ALTER TABLE [db].name DROP INDEX name` - Removes index description from tables metadata and deletes index files from disk.
+
+-   `ALTER TABLE [db.]table MATERIALIZE INDEX name IN PARTITION partition_name` - The query rebuilds the secondary index `name` in the partition `partition_name`. Implemented as a [mutation](../../../../sql-reference/statements/alter/index.md#mutations). To rebuild index over the whole data in the table you need to remove `IN PARTITION` from query.
+
+The first two commands are lightweight in a sense that they only change metadata or remove files.
+
+Also, they are replicated, syncing indices metadata via ZooKeeper.
+
+:::note    
+Index manipulation is supported only for tables with [`*MergeTree`](../../../../engines/table-engines/mergetree-family/mergetree.md) engine (including [replicated](../../../../engines/table-engines/mergetree-family/replication.md) variants).
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/statements/alter/order-by.md b/docs/en/reference/sql-reference/statements/alter/order-by.md
new file mode 100644
index 00000000000..84d29ae8e11
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/order-by.md
@@ -0,0 +1,18 @@
+---
+sidebar_position: 41
+sidebar_label: ORDER BY
+---
+
+# Manipulating Key Expressions {#manipulations-with-key-expressions}
+
+``` sql
+ALTER TABLE [db].name [ON CLUSTER cluster] MODIFY ORDER BY new_expression
+```
+
+The command changes the [sorting key](../../../engines/table-engines/mergetree-family/mergetree.md) of the table to `new_expression` (an expression or a tuple of expressions). Primary key remains the same.
+
+The command is lightweight in a sense that it only changes metadata. To keep the property that data part rows are ordered by the sorting key expression you cannot add expressions containing existing columns to the sorting key (only columns added by the `ADD COLUMN` command in the same `ALTER` query, without default column value).
+
+:::note    
+It only works for tables in the [`MergeTree`](../../../engines/table-engines/mergetree-family/mergetree.md) family (including [replicated](../../../engines/table-engines/mergetree-family/replication.md) tables).
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/statements/alter/partition.md b/docs/en/reference/sql-reference/statements/alter/partition.md
new file mode 100644
index 00000000000..453d1bd7bf6
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/partition.md
@@ -0,0 +1,328 @@
+---
+sidebar_position: 38
+sidebar_label: PARTITION
+---
+
+# Manipulating Partitions and Parts {#alter_manipulations-with-partitions}
+
+The following operations with [partitions](../../../engines/table-engines/mergetree-family/custom-partitioning-key.md) are available:
+
+-   [DETACH PARTITION](#alter_detach-partition) — Moves a partition to the `detached` directory and forget it.
+-   [DROP PARTITION](#alter_drop-partition) — Deletes a partition.
+-   [ATTACH PART\|PARTITION](#alter_attach-partition) — Adds a part or partition from the `detached` directory to the table.
+-   [ATTACH PARTITION FROM](#alter_attach-partition-from) — Copies the data partition from one table to another and adds.
+-   [REPLACE PARTITION](#alter_replace-partition) — Copies the data partition from one table to another and replaces.
+-   [MOVE PARTITION TO TABLE](#alter_move_to_table-partition) — Moves the data partition from one table to another.
+-   [CLEAR COLUMN IN PARTITION](#alter_clear-column-partition) — Resets the value of a specified column in a partition.
+-   [CLEAR INDEX IN PARTITION](#alter_clear-index-partition) — Resets the specified secondary index in a partition.
+-   [FREEZE PARTITION](#alter_freeze-partition) — Creates a backup of a partition.
+-   [UNFREEZE PARTITION](#alter_unfreeze-partition) — Removes a backup of a partition.
+-   [FETCH PARTITION\|PART](#alter_fetch-partition) — Downloads a part or partition from another server.
+-   [MOVE PARTITION\|PART](#alter_move-partition) — Move partition/data part to another disk or volume.
+-   [UPDATE IN PARTITION](#update-in-partition) — Update data inside the partition by condition.
+-   [DELETE IN PARTITION](#delete-in-partition) — Delete data inside the partition by condition.
+
+<!-- -->
+
+## DETACH PARTITION\|PART {#alter_detach-partition}
+
+``` sql
+ALTER TABLE table_name DETACH PARTITION|PART partition_expr
+```
+
+Moves all data for the specified partition to the `detached` directory. The server forgets about the detached data partition as if it does not exist. The server will not know about this data until you make the [ATTACH](#alter_attach-partition) query.
+
+Example:
+
+``` sql
+ALTER TABLE mt DETACH PARTITION '2020-11-21';
+ALTER TABLE mt DETACH PART 'all_2_2_0';
+```
+
+Read about setting the partition expression in a section [How to specify the partition expression](#alter-how-to-specify-part-expr).
+
+After the query is executed, you can do whatever you want with the data in the `detached` directory — delete it from the file system, or just leave it.
+
+This query is replicated – it moves the data to the `detached` directory on all replicas. Note that you can execute this query only on a leader replica. To find out if a replica is a leader, perform the `SELECT` query to the [system.replicas](../../../operations/system-tables/replicas.md#system_tables-replicas) table. Alternatively, it is easier to make a `DETACH` query on all replicas - all the replicas throw an exception, except the leader replicas (as multiple leaders are allowed).
+
+## DROP PARTITION\|PART {#alter_drop-partition}
+
+``` sql
+ALTER TABLE table_name DROP PARTITION|PART partition_expr
+```
+
+Deletes the specified partition from the table. This query tags the partition as inactive and deletes data completely, approximately in 10 minutes.
+
+Read about setting the partition expression in a section [How to specify the partition expression](#alter-how-to-specify-part-expr).
+
+The query is replicated – it deletes data on all replicas.
+
+Example:
+
+``` sql
+ALTER TABLE mt DROP PARTITION '2020-11-21';
+ALTER TABLE mt DROP PART 'all_4_4_0';
+```
+
+## DROP DETACHED PARTITION\|PART {#alter_drop-detached}
+
+``` sql
+ALTER TABLE table_name DROP DETACHED PARTITION|PART partition_expr
+```
+
+Removes the specified part or all parts of the specified partition from `detached`.
+Read more about setting the partition expression in a section [How to specify the partition expression](#alter-how-to-specify-part-expr).
+
+## ATTACH PARTITION\|PART {#alter_attach-partition}
+
+``` sql
+ALTER TABLE table_name ATTACH PARTITION|PART partition_expr
+```
+
+Adds data to the table from the `detached` directory. It is possible to add data for an entire partition or for a separate part. Examples:
+
+``` sql
+ALTER TABLE visits ATTACH PARTITION 201901;
+ALTER TABLE visits ATTACH PART 201901_2_2_0;
+```
+
+Read more about setting the partition expression in a section [How to specify the partition expression](#alter-how-to-specify-part-expr).
+
+This query is replicated. The replica-initiator checks whether there is data in the `detached` directory.
+If data exists, the query checks its integrity. If everything is correct, the query adds the data to the table.
+
+If the non-initiator replica, receiving the attach command, finds the part with the correct checksums in its own `detached` folder, it attaches the data without fetching it from other replicas.
+If there is no part with the correct checksums, the data is downloaded from any replica having the part.
+
+You can put data to the `detached` directory on one replica and use the `ALTER ... ATTACH` query to add it to the table on all replicas.
+
+## ATTACH PARTITION FROM {#alter_attach-partition-from}
+
+``` sql
+ALTER TABLE table2 ATTACH PARTITION partition_expr FROM table1
+```
+
+This query copies the data partition from `table1` to `table2`.
+Note that data will be deleted neither from `table1` nor from `table2`.
+
+For the query to run successfully, the following conditions must be met:
+
+-   Both tables must have the same structure.
+-   Both tables must have the same partition key.
+
+## REPLACE PARTITION {#alter_replace-partition}
+
+``` sql
+ALTER TABLE table2 REPLACE PARTITION partition_expr FROM table1
+```
+
+This query copies the data partition from the `table1` to `table2` and replaces existing partition in the `table2`. Note that data won’t be deleted from `table1`.
+
+For the query to run successfully, the following conditions must be met:
+
+-   Both tables must have the same structure.
+-   Both tables must have the same partition key.
+
+## MOVE PARTITION TO TABLE {#alter_move_to_table-partition}
+
+``` sql
+ALTER TABLE table_source MOVE PARTITION partition_expr TO TABLE table_dest
+```
+
+This query moves the data partition from the `table_source` to `table_dest` with deleting the data from `table_source`.
+
+For the query to run successfully, the following conditions must be met:
+
+-   Both tables must have the same structure.
+-   Both tables must have the same partition key.
+-   Both tables must be the same engine family (replicated or non-replicated).
+-   Both tables must have the same storage policy.
+
+## CLEAR COLUMN IN PARTITION {#alter_clear-column-partition}
+
+``` sql
+ALTER TABLE table_name CLEAR COLUMN column_name IN PARTITION partition_expr
+```
+
+Resets all values in the specified column in a partition. If the `DEFAULT` clause was determined when creating a table, this query sets the column value to a specified default value.
+
+Example:
+
+``` sql
+ALTER TABLE visits CLEAR COLUMN hour in PARTITION 201902
+```
+
+## FREEZE PARTITION {#alter_freeze-partition}
+
+``` sql
+ALTER TABLE table_name FREEZE [PARTITION partition_expr] [WITH NAME 'backup_name']
+```
+
+This query creates a local backup of a specified partition. If the `PARTITION` clause is omitted, the query creates the backup of all partitions at once.
+
+:::note    
+The entire backup process is performed without stopping the server.
+:::
+
+Note that for old-styled tables you can specify the prefix of the partition name (for example, `2019`) - then the query creates the backup for all the corresponding partitions. Read about setting the partition expression in a section [How to specify the partition expression](#alter-how-to-specify-part-expr).
+
+At the time of execution, for a data snapshot, the query creates hardlinks to a table data. Hardlinks are placed in the directory `/var/lib/clickhouse/shadow/N/...`, where:
+
+-   `/var/lib/clickhouse/` is the working ClickHouse directory specified in the config.
+-   `N` is the incremental number of the backup.
+-   if the `WITH NAME` parameter is specified, then the value of the `'backup_name'` parameter is used instead of the incremental number. 
+
+:::note    
+If you use [a set of disks for data storage in a table](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes), the `shadow/N` directory appears on every disk, storing data parts that matched by the `PARTITION` expression.
+:::
+
+The same structure of directories is created inside the backup as inside `/var/lib/clickhouse/`. The query performs `chmod` for all files, forbidding writing into them.
+
+After creating the backup, you can copy the data from `/var/lib/clickhouse/shadow/` to the remote server and then delete it from the local server. Note that the `ALTER t FREEZE PARTITION` query is not replicated. It creates a local backup only on the local server.
+
+The query creates backup almost instantly (but first it waits for the current queries to the corresponding table to finish running).
+
+`ALTER TABLE t FREEZE PARTITION` copies only the data, not table metadata. To make a backup of table metadata, copy the file `/var/lib/clickhouse/metadata/database/table.sql`
+
+To restore data from a backup, do the following:
+
+1.  Create the table if it does not exist. To view the query, use the .sql file (replace `ATTACH` in it with `CREATE`).
+2.  Copy the data from the `data/database/table/` directory inside the backup to the `/var/lib/clickhouse/data/database/table/detached/` directory.
+3.  Run `ALTER TABLE t ATTACH PARTITION` queries to add the data to a table.
+
+Restoring from a backup does not require stopping the server.
+
+For more information about backups and restoring data, see the [Data Backup](../../../operations/backup.md) section.
+
+## UNFREEZE PARTITION {#alter_unfreeze-partition}
+
+``` sql
+ALTER TABLE 'table_name' UNFREEZE [PARTITION 'part_expr'] WITH NAME 'backup_name'
+```
+
+Removes `freezed` partitions with the specified name from the disk. If the `PARTITION` clause is omitted, the query removes the backup of all partitions at once.
+
+## CLEAR INDEX IN PARTITION {#alter_clear-index-partition}
+
+``` sql
+ALTER TABLE table_name CLEAR INDEX index_name IN PARTITION partition_expr
+```
+
+The query works similar to `CLEAR COLUMN`, but it resets an index instead of a column data.
+
+## FETCH PARTITION|PART {#alter_fetch-partition}
+
+``` sql
+ALTER TABLE table_name FETCH PARTITION|PART partition_expr FROM 'path-in-zookeeper'
+```
+
+Downloads a partition from another server. This query only works for the replicated tables.
+
+The query does the following:
+
+1.  Downloads the partition|part from the specified shard. In ‘path-in-zookeeper’ you must specify a path to the shard in ZooKeeper.
+2.  Then the query puts the downloaded data to the `detached` directory of the `table_name` table. Use the [ATTACH PARTITION\|PART](#alter_attach-partition) query to add the data to the table.
+
+For example:
+
+1. FETCH PARTITION
+``` sql
+ALTER TABLE users FETCH PARTITION 201902 FROM '/clickhouse/tables/01-01/visits';
+ALTER TABLE users ATTACH PARTITION 201902;
+```
+2. FETCH PART
+``` sql
+ALTER TABLE users FETCH PART 201901_2_2_0 FROM '/clickhouse/tables/01-01/visits';
+ALTER TABLE users ATTACH PART 201901_2_2_0;
+```
+
+Note that:
+
+-   The `ALTER ... FETCH PARTITION|PART` query isn’t replicated. It places the part or partition to the `detached` directory only on the local server.
+-   The `ALTER TABLE ... ATTACH` query is replicated. It adds the data to all replicas. The data is added to one of the replicas from the `detached` directory, and to the others - from neighboring replicas.
+
+Before downloading, the system checks if the partition exists and the table structure matches. The most appropriate replica is selected automatically from the healthy replicas.
+
+Although the query is called `ALTER TABLE`, it does not change the table structure and does not immediately change the data available in the table.
+
+## MOVE PARTITION\|PART {#alter_move-partition}
+
+Moves partitions or data parts to another volume or disk for `MergeTree`-engine tables. See [Using Multiple Block Devices for Data Storage](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes).
+
+``` sql
+ALTER TABLE table_name MOVE PARTITION|PART partition_expr TO DISK|VOLUME 'disk_name'
+```
+
+The `ALTER TABLE t MOVE` query:
+
+-   Not replicated, because different replicas can have different storage policies.
+-   Returns an error if the specified disk or volume is not configured. Query also returns an error if conditions of data moving, that specified in the storage policy, can’t be applied.
+-   Can return an error in the case, when data to be moved is already moved by a background process, concurrent `ALTER TABLE t MOVE` query or as a result of background data merging. A user shouldn’t perform any additional actions in this case.
+
+Example:
+
+``` sql
+ALTER TABLE hits MOVE PART '20190301_14343_16206_438' TO VOLUME 'slow'
+ALTER TABLE hits MOVE PARTITION '2019-09-01' TO DISK 'fast_ssd'
+```
+
+## UPDATE IN PARTITION {#update-in-partition}
+
+Manipulates data in the specifies partition matching the specified filtering expression. Implemented as a [mutation](../../../sql-reference/statements/alter/index.md#mutations).
+
+Syntax:
+
+``` sql
+ALTER TABLE [db.]table UPDATE column1 = expr1 [, ...] [IN PARTITION partition_id] WHERE filter_expr
+```
+
+### Example
+
+``` sql
+ALTER TABLE mt UPDATE x = x + 1 IN PARTITION 2 WHERE p = 2;
+```
+
+### See Also
+
+-   [UPDATE](../../../sql-reference/statements/alter/update.md#alter-table-update-statements)
+
+## DELETE IN PARTITION {#delete-in-partition}
+
+Deletes data in the specifies partition matching the specified filtering expression. Implemented as a [mutation](../../../sql-reference/statements/alter/index.md#mutations).
+
+Syntax:
+
+``` sql
+ALTER TABLE [db.]table DELETE [IN PARTITION partition_id] WHERE filter_expr
+```
+
+### Example
+
+``` sql
+ALTER TABLE mt DELETE IN PARTITION 2 WHERE p = 2;
+```
+
+### See Also
+
+-   [DELETE](../../../sql-reference/statements/alter/delete.md#alter-mutations)
+
+## How to Set Partition Expression {#alter-how-to-specify-part-expr}
+
+You can specify the partition expression in `ALTER ... PARTITION` queries in different ways:
+
+-   As a value from the `partition` column of the `system.parts` table. For example, `ALTER TABLE visits DETACH PARTITION 201901`.
+-   As a tuple of expressions or constants that matches (in types) the table partitioning keys tuple. In the case of a single element partitioning key, the expression should be wrapped in the `tuple (...)` function. For example, `ALTER TABLE visits DETACH PARTITION tuple(toYYYYMM(toDate('2019-01-25')))`.
+-   Using the partition ID. Partition ID is a string identifier of the partition (human-readable, if possible) that is used as the names of partitions in the file system and in ZooKeeper. The partition ID must be specified in the `PARTITION ID` clause, in a single quotes. For example, `ALTER TABLE visits DETACH PARTITION ID '201901'`.
+-   In the [ALTER ATTACH PART](#alter_attach-partition) and [DROP DETACHED PART](#alter_drop-detached) query, to specify the name of a part, use string literal with a value from the `name` column of the [system.detached_parts](../../../operations/system-tables/detached_parts.md#system_tables-detached_parts) table. For example, `ALTER TABLE visits ATTACH PART '201901_1_1_0'`.
+
+Usage of quotes when specifying the partition depends on the type of partition expression. For example, for the `String` type, you have to specify its name in quotes (`'`). For the `Date` and `Int*` types no quotes are needed.
+
+All the rules above are also true for the [OPTIMIZE](../../../sql-reference/statements/misc.md#misc_operations-optimize) query. If you need to specify the only partition when optimizing a non-partitioned table, set the expression `PARTITION tuple()`. For example:
+
+``` sql
+OPTIMIZE TABLE table_not_partitioned PARTITION tuple() FINAL;
+```
+
+`IN PARTITION` specifies the partition to which the [UPDATE](../../../sql-reference/statements/alter/update.md#alter-table-update-statements) or [DELETE](../../../sql-reference/statements/alter/delete.md#alter-mutations) expressions are applied as a result of the `ALTER TABLE` query. New parts are created only from the specified partition. In this way, `IN PARTITION` helps to reduce the load when the table is divided into many partitions, and you only need to update the data point-by-point.
+
+The examples of `ALTER ... PARTITION` queries are demonstrated in the tests [`00502_custom_partitioning_local`](https://github.com/ClickHouse/ClickHouse/blob/master/tests/queries/0_stateless/00502_custom_partitioning_local.sql) and [`00502_custom_partitioning_replicated_zookeeper`](https://github.com/ClickHouse/ClickHouse/blob/master/tests/queries/0_stateless/00502_custom_partitioning_replicated_zookeeper.sql).
diff --git a/docs/en/reference/sql-reference/statements/alter/projection.md b/docs/en/reference/sql-reference/statements/alter/projection.md
new file mode 100644
index 00000000000..5ccf33d2d2f
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/projection.md
@@ -0,0 +1,25 @@
+---
+sidebar_position: 49
+sidebar_label: PROJECTION
+---
+
+# Manipulating Projections {#manipulations-with-projections}
+
+The following operations with [projections](../../../engines/table-engines/mergetree-family/mergetree.md#projections) are available:
+
+-   `ALTER TABLE [db].name ADD PROJECTION name ( SELECT <COLUMN LIST EXPR> [GROUP BY] [ORDER BY] )` - Adds projection description to tables metadata.
+
+-   `ALTER TABLE [db].name DROP PROJECTION name` - Removes projection description from tables metadata and deletes projection files from disk. Implemented as a [mutation](../../../sql-reference/statements/alter/index.md#mutations).
+
+-   `ALTER TABLE [db.]table MATERIALIZE PROJECTION name IN PARTITION partition_name` - The query rebuilds the projection `name` in the partition `partition_name`. Implemented as a [mutation](../../../sql-reference/statements/alter/index.md#mutations).
+
+-   `ALTER TABLE [db.]table CLEAR PROJECTION name IN PARTITION partition_name` - Deletes projection files from disk without removing description. Implemented as a [mutation](../../../sql-reference/statements/alter/index.md#mutations).
+
+
+The commands `ADD`, `DROP` and `CLEAR` are lightweight in a sense that they only change metadata or remove files.
+
+Also, they are replicated, syncing projections metadata via ZooKeeper.
+
+:::note    
+Projection manipulation is supported only for tables with [`*MergeTree`](../../../engines/table-engines/mergetree-family/mergetree.md) engine (including [replicated](../../../engines/table-engines/mergetree-family/replication.md) variants).
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/statements/alter/quota.md b/docs/en/reference/sql-reference/statements/alter/quota.md
new file mode 100644
index 00000000000..2398a57502c
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/quota.md
@@ -0,0 +1,39 @@
+---
+sidebar_position: 46
+sidebar_label: QUOTA
+---
+
+# ALTER QUOTA {#alter-quota-statement}
+
+Changes quotas.
+
+Syntax:
+
+``` sql
+ALTER QUOTA [IF EXISTS] name [ON CLUSTER cluster_name]
+    [RENAME TO new_name]
+    [KEYED BY {user_name | ip_address | client_key | client_key,user_name | client_key,ip_address} | NOT KEYED]
+    [FOR [RANDOMIZED] INTERVAL number {second | minute | hour | day | week | month | quarter | year}
+        {MAX { {queries | query_selects | query_inserts | errors | result_rows | result_bytes | read_rows | read_bytes | execution_time} = number } [,...] |
+        NO LIMITS | TRACKING ONLY} [,...]]
+    [TO {role [,...] | ALL | ALL EXCEPT role [,...]}]
+```
+Keys `user_name`, `ip_address`, `client_key`, `client_key, user_name` and `client_key, ip_address` correspond to the fields in the [system.quotas](../../../operations/system-tables/quotas.md) table.
+
+Parameters `queries`, `query_selects`, 'query_inserts', errors`, `result_rows`, `result_bytes`, `read_rows`, `read_bytes`, `execution_time` correspond to the fields in the [system.quotas_usage](../../../operations/system-tables/quotas_usage.md) table.
+
+`ON CLUSTER` clause allows creating quotas on a cluster, see [Distributed DDL](../../../sql-reference/distributed-ddl.md).
+
+**Examples**
+
+Limit the maximum number of queries for the current user with 123 queries in 15 months constraint:
+
+``` sql
+ALTER QUOTA IF EXISTS qA FOR INTERVAL 15 month MAX queries = 123 TO CURRENT_USER;
+```
+
+For the default user limit the maximum execution time with half a second in 30 minutes, and limit the maximum number of queries with 321 and the maximum number of errors with 10 in 5 quaters:
+
+``` sql
+ALTER QUOTA IF EXISTS qB FOR INTERVAL 30 minute MAX execution_time = 0.5, FOR INTERVAL 5 quarter MAX queries = 321, errors = 10 TO default;
+```
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/statements/alter/role.md b/docs/en/reference/sql-reference/statements/alter/role.md
new file mode 100644
index 00000000000..d3cb28a1705
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/role.md
@@ -0,0 +1,16 @@
+---
+sidebar_position: 46
+sidebar_label: ROLE
+---
+
+## ALTER ROLE {#alter-role-statement}
+
+Changes roles.
+
+Syntax:
+
+``` sql
+ALTER ROLE [IF EXISTS] name1 [ON CLUSTER cluster_name1] [RENAME TO new_name1]
+        [, name2 [ON CLUSTER cluster_name2] [RENAME TO new_name2] ...]
+    [SETTINGS variable [= value] [MIN [=] min_value] [MAX [=] max_value] [READONLY|WRITABLE] | PROFILE 'profile_name'] [,...]
+```
diff --git a/docs/en/reference/sql-reference/statements/alter/row-policy.md b/docs/en/reference/sql-reference/statements/alter/row-policy.md
new file mode 100644
index 00000000000..47207d29287
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/row-policy.md
@@ -0,0 +1,19 @@
+---
+sidebar_position: 47
+sidebar_label: ROW POLICY
+---
+
+# ALTER ROW POLICY {#alter-row-policy-statement}
+
+Changes row policy.
+
+Syntax:
+
+``` sql
+ALTER [ROW] POLICY [IF EXISTS] name1 [ON CLUSTER cluster_name1] ON [database1.]table1 [RENAME TO new_name1]
+        [, name2 [ON CLUSTER cluster_name2] ON [database2.]table2 [RENAME TO new_name2] ...]
+    [AS {PERMISSIVE | RESTRICTIVE}]
+    [FOR SELECT]
+    [USING {condition | NONE}][,...]
+    [TO {role [,...] | ALL | ALL EXCEPT role [,...]}]
+```
diff --git a/docs/en/reference/sql-reference/statements/alter/sample-by.md b/docs/en/reference/sql-reference/statements/alter/sample-by.md
new file mode 100644
index 00000000000..08e4fe1066b
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/sample-by.md
@@ -0,0 +1,20 @@
+---
+sidebar_position: 41
+sidebar_label: SAMPLE BY
+---
+
+# Manipulating Sampling-Key Expressions {#manipulations-with-sampling-key-expressions}
+
+Syntax:
+
+``` sql
+ALTER TABLE [db].name [ON CLUSTER cluster] MODIFY SAMPLE BY new_expression
+```
+
+The command changes the [sampling key](../../../engines/table-engines/mergetree-family/mergetree.md) of the table to `new_expression` (an expression or a tuple of expressions).
+
+The command is lightweight in the sense that it only changes metadata. The primary key must contain the new sample key.
+
+:::note    
+It only works for tables in the [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md) family (including [replicated](../../../engines/table-engines/mergetree-family/replication.md) tables).
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/statements/alter/setting.md b/docs/en/reference/sql-reference/statements/alter/setting.md
new file mode 100644
index 00000000000..bb361e2ee6f
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/setting.md
@@ -0,0 +1,60 @@
+---
+sidebar_position: 38
+sidebar_label: SETTING
+---
+
+# Table Settings Manipulations {#table_settings_manipulations}
+
+There is a set of queries to change table settings. You can modify settings or reset them to default values. A single query can change several settings at once.
+If a setting with the specified name does not exist, then the query raises an exception.
+
+**Syntax**
+
+``` sql
+ALTER TABLE [db].name [ON CLUSTER cluster] MODIFY|RESET SETTING ...
+```
+
+:::note    
+These queries can be applied to [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md) tables only.
+:::
+
+## MODIFY SETTING {#alter_modify_setting}
+
+Changes table settings.
+
+**Syntax**
+
+```sql
+MODIFY SETTING setting_name=value [, ...]
+```
+
+**Example**
+
+```sql
+CREATE TABLE example_table (id UInt32, data String) ENGINE=MergeTree() ORDER BY id;
+
+ALTER TABLE example_table MODIFY SETTING max_part_loading_threads=8, max_parts_in_total=50000;
+```
+
+## RESET SETTING {#alter_reset_setting}
+
+Resets table settings to their default values. If a setting is in a default state, then no action is taken.
+
+**Syntax**
+
+```sql
+RESET SETTING setting_name [, ...]
+```
+
+**Example**
+
+```sql
+CREATE TABLE example_table (id UInt32, data String) ENGINE=MergeTree() ORDER BY id
+    SETTINGS max_part_loading_threads=8;
+
+ALTER TABLE example_table RESET SETTING max_part_loading_threads;
+```
+
+**See Also**
+
+-   [MergeTree settings](../../../operations/settings/merge-tree-settings.md)
diff --git a/docs/en/reference/sql-reference/statements/alter/settings-profile.md b/docs/en/reference/sql-reference/statements/alter/settings-profile.md
new file mode 100644
index 00000000000..b1728f21c08
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/settings-profile.md
@@ -0,0 +1,16 @@
+---
+sidebar_position: 48
+sidebar_label: SETTINGS PROFILE
+---
+
+## ALTER SETTINGS PROFILE {#alter-settings-profile-statement}
+
+Changes settings profiles.
+
+Syntax:
+
+``` sql
+ALTER SETTINGS PROFILE [IF EXISTS] TO name1 [ON CLUSTER cluster_name1] [RENAME TO new_name1]
+        [, name2 [ON CLUSTER cluster_name2] [RENAME TO new_name2] ...]
+    [SETTINGS variable [= value] [MIN [=] min_value] [MAX [=] max_value] [READONLY|WRITABLE] | INHERIT 'profile_name'] [,...]
+```
diff --git a/docs/en/reference/sql-reference/statements/alter/ttl.md b/docs/en/reference/sql-reference/statements/alter/ttl.md
new file mode 100644
index 00000000000..f2cf8724197
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/ttl.md
@@ -0,0 +1,85 @@
+---
+sidebar_position: 44
+sidebar_label: TTL
+---
+
+# Manipulations with Table TTL {#manipulations-with-table-ttl}
+
+## MODIFY TTL {#modify-ttl}
+
+You can change [table TTL](../../../engines/table-engines/mergetree-family/mergetree.md#mergetree-table-ttl) with a request of the following form:
+
+``` sql
+ALTER TABLE table_name MODIFY TTL ttl_expression;
+```
+
+## REMOVE TTL {#remove-ttl}
+
+TTL-property can be removed from table with the following query:
+
+```sql
+ALTER TABLE table_name REMOVE TTL
+```
+
+**Example**
+
+Consider the table with table `TTL`:
+
+```sql
+CREATE TABLE table_with_ttl
+(
+    event_time DateTime,
+    UserID UInt64,
+    Comment String
+)
+ENGINE MergeTree()
+ORDER BY tuple()
+TTL event_time + INTERVAL 3 MONTH;
+SETTINGS min_bytes_for_wide_part = 0;
+
+INSERT INTO table_with_ttl VALUES (now(), 1, 'username1');
+
+INSERT INTO table_with_ttl VALUES (now() - INTERVAL 4 MONTH, 2, 'username2');
+```
+
+Run `OPTIMIZE` to force `TTL` cleanup:
+
+```sql
+OPTIMIZE TABLE table_with_ttl FINAL;
+SELECT * FROM table_with_ttl FORMAT PrettyCompact;
+```
+Second row was deleted from table.
+
+```text
+┌─────────event_time────┬──UserID─┬─────Comment──┐
+│   2020-12-11 12:44:57 │       1 │    username1 │
+└───────────────────────┴─────────┴──────────────┘
+```
+
+Now remove table `TTL` with the following query:
+
+```sql
+ALTER TABLE table_with_ttl REMOVE TTL;
+```
+
+Re-insert the deleted row and force the `TTL` cleanup again with `OPTIMIZE`:
+
+```sql
+INSERT INTO table_with_ttl VALUES (now() - INTERVAL 4 MONTH, 2, 'username2');
+OPTIMIZE TABLE table_with_ttl FINAL;
+SELECT * FROM table_with_ttl FORMAT PrettyCompact;
+```
+
+The `TTL` is no longer there, so the second row is not deleted:
+
+```text
+┌─────────event_time────┬──UserID─┬─────Comment──┐
+│   2020-12-11 12:44:57 │       1 │    username1 │
+│   2020-08-11 12:44:57 │       2 │    username2 │
+└───────────────────────┴─────────┴──────────────┘
+```
+
+**See Also**
+
+- More about the [TTL-expression](../../../sql-reference/statements/create/table.md#ttl-expression).
+- Modify column [with TTL](../../../sql-reference/statements/alter/column.md#alter_modify-column).
diff --git a/docs/en/reference/sql-reference/statements/alter/update.md b/docs/en/reference/sql-reference/statements/alter/update.md
new file mode 100644
index 00000000000..aeff7cfa1b2
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/update.md
@@ -0,0 +1,29 @@
+---
+sidebar_position: 40
+sidebar_label: UPDATE
+---
+
+# ALTER TABLE … UPDATE Statements {#alter-table-update-statements}
+
+``` sql
+ALTER TABLE [db.]table UPDATE column1 = expr1 [, ...] WHERE filter_expr
+```
+
+Manipulates data matching the specified filtering expression. Implemented as a [mutation](../../../sql-reference/statements/alter/index.md#mutations).
+
+:::note    
+The `ALTER TABLE` prefix makes this syntax different from most other systems supporting SQL. It is intended to signify that unlike similar queries in OLTP databases this is a heavy operation not designed for frequent use.
+:::
+
+The `filter_expr` must be of type `UInt8`. This query updates values of specified columns to the values of corresponding expressions in rows for which the `filter_expr` takes a non-zero value. Values are casted to the column type using the `CAST` operator. Updating columns that are used in the calculation of the primary or the partition key is not supported.
+
+One query can contain several commands separated by commas.
+
+The synchronicity of the query processing is defined by the [mutations_sync](../../../operations/settings/settings.md#mutations_sync) setting. By default, it is asynchronous.
+
+**See also**
+
+-   [Mutations](../../../sql-reference/statements/alter/index.md#mutations)
+-   [Synchronicity of ALTER Queries](../../../sql-reference/statements/alter/index.md#synchronicity-of-alter-queries)
+-   [mutations_sync](../../../operations/settings/settings.md#mutations_sync) setting
+
diff --git a/docs/en/reference/sql-reference/statements/alter/user.md b/docs/en/reference/sql-reference/statements/alter/user.md
new file mode 100644
index 00000000000..f9b90349dab
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/user.md
@@ -0,0 +1,63 @@
+---
+sidebar_position: 45
+sidebar_label: USER
+---
+
+# ALTER USER {#alter-user-statement}
+
+Changes ClickHouse user accounts.
+
+Syntax:
+
+``` sql
+ALTER USER [IF EXISTS] name1 [ON CLUSTER cluster_name1] [RENAME TO new_name1]
+        [, name2 [ON CLUSTER cluster_name2] [RENAME TO new_name2] ...]
+    [NOT IDENTIFIED | IDENTIFIED {[WITH {no_password | plaintext_password | sha256_password | sha256_hash | double_sha1_password | double_sha1_hash}] BY {'password' | 'hash'}} | {WITH ldap SERVER 'server_name'} | {WITH kerberos [REALM 'realm']}]
+    [[ADD | DROP] HOST {LOCAL | NAME 'name' | REGEXP 'name_regexp' | IP 'address' | LIKE 'pattern'} [,...] | ANY | NONE]
+    [DEFAULT ROLE role [,...] | ALL | ALL EXCEPT role [,...] ]
+    [GRANTEES {user | role | ANY | NONE} [,...] [EXCEPT {user | role} [,...]]]
+    [SETTINGS variable [= value] [MIN [=] min_value] [MAX [=] max_value] [READONLY | WRITABLE] | PROFILE 'profile_name'] [,...]
+```
+
+To use `ALTER USER` you must have the [ALTER USER](../../../sql-reference/statements/grant.md#grant-access-management) privilege.
+
+## GRANTEES Clause {#grantees}
+
+Specifies users or roles which are allowed to receive [privileges](../../../sql-reference/statements/grant.md#grant-privileges) from this user on the condition this user has also all required access granted with [GRANT OPTION](../../../sql-reference/statements/grant.md#grant-privigele-syntax). Options of the `GRANTEES` clause:
+
+-   `user` — Specifies a user this user can grant privileges to.
+-   `role` — Specifies a role this user can grant privileges to.
+-   `ANY` — This user can grant privileges to anyone. It's the default setting.
+-   `NONE` — This user can grant privileges to none.
+
+You can exclude any user or role by using the `EXCEPT` expression. For example, `ALTER USER user1 GRANTEES ANY EXCEPT user2`. It means if `user1` has some privileges granted with `GRANT OPTION` it will be able to grant those privileges to anyone except `user2`.
+
+## Examples {#alter-user-examples}
+
+Set assigned roles as default:
+
+``` sql
+ALTER USER user DEFAULT ROLE role1, role2
+```
+
+If roles aren’t previously assigned to a user, ClickHouse throws an exception.
+
+Set all the assigned roles to default:
+
+``` sql
+ALTER USER user DEFAULT ROLE ALL
+```
+
+If a role is assigned to a user in the future, it will become default automatically.
+
+Set all the assigned roles to default, excepting `role1` and `role2`:
+
+``` sql
+ALTER USER user DEFAULT ROLE ALL EXCEPT role1, role2
+```
+
+Allows the user with `john` account to grant his privileges to the user with `jack` account:
+
+``` sql
+ALTER USER john GRANTEES jack;
+```
diff --git a/docs/en/reference/sql-reference/statements/alter/view.md b/docs/en/reference/sql-reference/statements/alter/view.md
new file mode 100644
index 00000000000..71e89aaefe8
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/alter/view.md
@@ -0,0 +1,44 @@
+---
+sidebar_position: 50
+sidebar_label: VIEW
+---
+
+# ALTER TABLE … MODIFY QUERY Statement {#alter-modify-query}
+
+You can modify `SELECT` query that was specified when a [materialized view](../create/view.md#materialized) was created with the `ALTER TABLE … MODIFY QUERY` statement. Use it when the materialized view was created without the `TO [db.]name` clause. The `allow_experimental_alter_materialized_view_structure` setting must be enabled. 
+
+If a materialized view uses the `TO [db.]name` construction, you must [DETACH](../detach.md) the view, run [ALTER TABLE](index.md) query for the target table, and then [ATTACH](../attach.md) the previously detached (`DETACH`) view.
+
+**Example**
+
+```sql
+CREATE TABLE src_table (`a` UInt32) ENGINE = MergeTree ORDER BY a;
+CREATE MATERIALIZED VIEW mv (`a` UInt32) ENGINE = MergeTree ORDER BY a AS SELECT a FROM src_table; 
+INSERT INTO src_table (a) VALUES (1), (2);
+SELECT * FROM mv;
+```
+```text
+┌─a─┐
+│ 1 │
+│ 2 │
+└───┘
+```
+```sql
+ALTER TABLE mv MODIFY QUERY SELECT a * 2 as a FROM src_table;
+INSERT INTO src_table (a) VALUES (3), (4);
+SELECT * FROM mv;
+```
+```text
+┌─a─┐
+│ 6 │
+│ 8 │
+└───┘
+┌─a─┐
+│ 1 │
+│ 2 │
+└───┘
+```
+
+## ALTER LIVE VIEW Statement {#alter-live-view}
+
+`ALTER LIVE VIEW ... REFRESH` statement refreshes a [Live view](../create/view.md#live-view). See [Force Live View Refresh](../create/view.md#live-view-alter-refresh).
diff --git a/docs/en/reference/sql-reference/statements/attach.md b/docs/en/reference/sql-reference/statements/attach.md
new file mode 100644
index 00000000000..bc7b2be333f
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/attach.md
@@ -0,0 +1,81 @@
+---
+sidebar_position: 40
+sidebar_label: ATTACH
+---
+
+# ATTACH Statement {#attach}
+
+Attaches a table or a dictionary, for example, when moving a database to another server.
+
+**Syntax**
+
+``` sql
+ATTACH TABLE|DICTIONARY [IF NOT EXISTS] [db.]name [ON CLUSTER cluster] ...
+```
+
+The query does not create data on the disk, but assumes that data is already in the appropriate places, and just adds information about the table or the dictionary to the server. After executing the `ATTACH` query, the server will know about the existence of the table or the dictionary.
+
+If a table was previously detached ([DETACH](../../sql-reference/statements/detach.md) query), meaning that its structure is known, you can use shorthand without defining the structure.
+
+## Attach Existing Table {#attach-existing-table}
+
+**Syntax**
+
+``` sql
+ATTACH TABLE [IF NOT EXISTS] [db.]name [ON CLUSTER cluster]
+```
+
+This query is used when starting the server. The server stores table metadata as files with `ATTACH` queries, which it simply runs at launch (with the exception of some system tables, which are explicitly created on the server).
+
+If the table was detached permanently, it won't be reattached at the server start, so you need to use `ATTACH` query explicitly.
+
+## Create New Table And Attach Data {#create-new-table-and-attach-data}
+
+### With Specified Path to Table Data {#attach-with-specified-path}
+
+The query creates a new table with provided structure and attaches table data from the provided directory in `user_files`.
+
+**Syntax**
+
+```sql
+ATTACH TABLE name FROM 'path/to/data/' (col1 Type1, ...)
+```
+
+**Example**
+
+Query:
+
+```sql
+DROP TABLE IF EXISTS test;
+INSERT INTO TABLE FUNCTION file('01188_attach/test/data.TSV', 'TSV', 's String, n UInt8') VALUES ('test', 42);
+ATTACH TABLE test FROM '01188_attach/test' (s String, n UInt8) ENGINE = File(TSV);
+SELECT * FROM test;
+```
+Result:
+
+```sql
+┌─s────┬──n─┐
+│ test │ 42 │
+└──────┴────┘
+```
+
+### With Specified Table UUID {#attach-with-specified-uuid}
+
+This query creates a new table with provided structure and attaches data from the table with the specified UUID.
+It is supported by the [Atomic](../../engines/database-engines/atomic.md) database engine.
+
+**Syntax**
+
+```sql
+ATTACH TABLE name UUID '<uuid>' (col1 Type1, ...)
+```
+
+## Attach Existing Dictionary {#attach-existing-dictionary}
+
+Attaches a previously detached dictionary.
+
+**Syntax**
+
+``` sql
+ATTACH DICTIONARY [IF NOT EXISTS] [db.]name [ON CLUSTER cluster]
+```
diff --git a/docs/en/reference/sql-reference/statements/check-table.md b/docs/en/reference/sql-reference/statements/check-table.md
new file mode 100644
index 00000000000..1164a8b8be6
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/check-table.md
@@ -0,0 +1,69 @@
+---
+sidebar_position: 41
+sidebar_label: CHECK
+---
+
+# CHECK TABLE Statement {#check-table}
+
+Checks if the data in the table is corrupted.
+
+``` sql
+CHECK TABLE [db.]name
+```
+
+The `CHECK TABLE` query compares actual file sizes with the expected values which are stored on the server. If the file sizes do not match the stored values, it means the data is corrupted. This can be caused, for example, by a system crash during query execution.
+
+The query response contains the `result` column with a single row. The row has a value of
+[Boolean](../../sql-reference/data-types/boolean.md) type:
+
+-   0 - The data in the table is corrupted.
+-   1 - The data maintains integrity.
+
+The `CHECK TABLE` query supports the following table engines:
+
+-   [Log](../../engines/table-engines/log-family/log.md)
+-   [TinyLog](../../engines/table-engines/log-family/tinylog.md)
+-   [StripeLog](../../engines/table-engines/log-family/stripelog.md)
+-   [MergeTree family](../../engines/table-engines/mergetree-family/mergetree.md)
+
+Performed over the tables with another table engines causes an exception.
+
+Engines from the `*Log` family do not provide automatic data recovery on failure. Use the `CHECK TABLE` query to track data loss in a timely manner.
+
+## Checking the MergeTree Family Tables {#checking-mergetree-tables}
+
+For `MergeTree` family engines, if [check_query_single_value_result](../../operations/settings/settings.md#check_query_single_value_result) = 0, the `CHECK TABLE` query shows a check status for every individual data part of a table on the local server.
+
+```sql
+SET check_query_single_value_result = 0;
+CHECK TABLE test_table;
+```
+
+```text
+┌─part_path─┬─is_passed─┬─message─┐
+│ all_1_4_1 │         1 │         │
+│ all_1_4_2 │         1 │         │
+└───────────┴───────────┴─────────┘
+```
+
+If `check_query_single_value_result` = 1, the `CHECK TABLE` query shows the general table check status.
+
+```sql
+SET check_query_single_value_result = 1;
+CHECK TABLE test_table;
+```
+
+```text
+┌─result─┐
+│      1 │
+└────────┘
+```
+
+## If the Data Is Corrupted {#if-data-is-corrupted}
+
+If the table is corrupted, you can copy the non-corrupted data to another table. To do this:
+
+1.  Create a new table with the same structure as damaged table. To do this execute the query `CREATE TABLE <new_table_name> AS <damaged_table_name>`.
+2.  Set the [max_threads](../../operations/settings/settings.md#settings-max_threads) value to 1 to process the next query in a single thread. To do this run the query `SET max_threads = 1`.
+3.  Execute the query `INSERT INTO <new_table_name> SELECT * FROM <damaged_table_name>`. This request copies the non-corrupted data from the damaged table to another table. Only the data before the corrupted part will be copied.
+4.  Restart the `clickhouse-client` to reset the `max_threads` value.
diff --git a/docs/en/reference/sql-reference/statements/create/database.md b/docs/en/reference/sql-reference/statements/create/database.md
new file mode 100644
index 00000000000..18ed94bef79
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/create/database.md
@@ -0,0 +1,58 @@
+---
+sidebar_position: 35
+sidebar_label: DATABASE
+---
+
+# CREATE DATABASE {#query-language-create-database}
+
+Creates a new database.
+
+``` sql
+CREATE DATABASE [IF NOT EXISTS] db_name [ON CLUSTER cluster] [ENGINE = engine(...)] [COMMENT 'Comment']
+```
+
+## Clauses {#clauses}
+
+### IF NOT EXISTS {#if-not-exists}
+
+If the `db_name` database already exists, then ClickHouse does not create a new database and:
+
+-   Doesn’t throw an exception if clause is specified.
+-   Throws an exception if clause isn’t specified.
+
+### ON CLUSTER {#on-cluster}
+
+ClickHouse creates the `db_name` database on all the servers of a specified cluster. More details in a [Distributed DDL](../../../sql-reference/distributed-ddl.md) article.
+
+### ENGINE {#engine}
+
+By default, ClickHouse uses its own [Atomic](../../../engines/database-engines/atomic.md) database engine. There are also [Lazy](../../../engines/database-engines/lazy.md), [MySQL](../../../engines/database-engines/mysql.md), [PostgresSQL](../../../engines/database-engines/postgresql.md), [MaterializedMySQL](../../../engines/database-engines/materialized-mysql.md), [MaterializedPostgreSQL](../../../engines/database-engines/materialized-postgresql.md), [Replicated](../../../engines/database-engines/replicated.md), [SQLite](../../../engines/database-engines/sqlite.md).
+
+### COMMENT {#comment}
+
+You can add a comment to the database when you creating it.
+
+The comment is supported for all database engines.
+
+**Syntax**
+
+``` sql
+CREATE DATABASE db_name ENGINE = engine(...) COMMENT 'Comment'
+```
+
+**Example**
+
+Query:
+
+``` sql
+CREATE DATABASE db_comment ENGINE = Memory COMMENT 'The temporary database';
+SELECT name, comment FROM system.databases WHERE name = 'db_comment';
+```
+
+Result:
+
+```text
+┌─name───────┬─comment────────────────┐
+│ db_comment │ The temporary database │
+└────────────┴────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/statements/create/dictionary.md b/docs/en/reference/sql-reference/statements/create/dictionary.md
new file mode 100644
index 00000000000..246625cc901
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/create/dictionary.md
@@ -0,0 +1,99 @@
+---
+sidebar_position: 38
+sidebar_label: DICTIONARY
+---
+
+# CREATE DICTIONARY {#create-dictionary-query}
+
+Creates a new [external dictionary](../../../sql-reference/dictionaries/external-dictionaries/external-dicts.md) with given [structure](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-structure.md), [source](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md), [layout](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md) and [lifetime](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-lifetime.md).
+
+**Syntax**
+
+``` sql
+CREATE [OR REPLACE] DICTIONARY [IF NOT EXISTS] [db.]dictionary_name [ON CLUSTER cluster]
+(
+    key1 type1  [DEFAULT|EXPRESSION expr1] [IS_OBJECT_ID],
+    key2 type2  [DEFAULT|EXPRESSION expr2],
+    attr1 type2 [DEFAULT|EXPRESSION expr3] [HIERARCHICAL|INJECTIVE],
+    attr2 type2 [DEFAULT|EXPRESSION expr4] [HIERARCHICAL|INJECTIVE]
+)
+PRIMARY KEY key1, key2
+SOURCE(SOURCE_NAME([param1 value1 ... paramN valueN]))
+LAYOUT(LAYOUT_NAME([param_name param_value]))
+LIFETIME({MIN min_val MAX max_val | max_val})
+SETTINGS(setting_name = setting_value, setting_name = setting_value, ...)
+COMMENT 'Comment'
+```
+
+External dictionary structure consists of attributes. Dictionary attributes are specified similarly to table columns. The only required attribute property is its type, all other properties may have default values.
+
+`ON CLUSTER` clause allows creating dictionary on a cluster, see [Distributed DDL](../../../sql-reference/distributed-ddl.md).
+
+Depending on dictionary [layout](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-layout.md) one or more attributes can be specified as dictionary keys.
+
+For more information, see [External Dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts.md) section.
+
+You can add a comment to the dictionary when you creating it using `COMMENT` clause.
+
+**Example**
+
+Input table `source_table`:
+
+``` text
+┌─id─┬─value──┐
+│  1 │ First  │
+│  2 │ Second │
+└────┴────────┘
+```
+
+Creating the dictionary:
+
+``` sql
+CREATE DICTIONARY dictionary_with_comment
+(
+    id UInt64,
+    value String
+)
+PRIMARY KEY id
+SOURCE(CLICKHOUSE(HOST 'localhost' PORT tcpPort() TABLE 'source_table'))
+LAYOUT(FLAT())
+LIFETIME(MIN 0 MAX 1000)
+COMMENT 'The temporary dictionary';
+```
+
+Output the dictionary:
+
+``` sql
+SHOW CREATE DICTIONARY dictionary_with_comment;
+```
+
+```text
+┌─statement───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
+│ CREATE DICTIONARY default.dictionary_with_comment
+(
+    `id` UInt64,
+    `value` String
+)
+PRIMARY KEY id
+SOURCE(CLICKHOUSE(HOST 'localhost' PORT tcpPort() TABLE 'source_table'))
+LIFETIME(MIN 0 MAX 1000)
+LAYOUT(FLAT())
+COMMENT 'The temporary dictionary' │
+└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+```
+
+Output the comment to dictionary:
+
+``` sql
+SELECT comment FROM system.dictionaries WHERE name == 'dictionary_with_comment' AND database == currentDatabase();
+```
+
+```text
+┌─comment──────────────────┐
+│ The temporary dictionary │
+└──────────────────────────┘
+```
+
+**See Also**
+
+-   [system.dictionaries](../../../operations/system-tables/dictionaries.md) — This table contains information about [external dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts.md).
diff --git a/docs/en/reference/sql-reference/statements/create/function.md b/docs/en/reference/sql-reference/statements/create/function.md
new file mode 100644
index 00000000000..a87d3d70e54
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/create/function.md
@@ -0,0 +1,59 @@
+---
+sidebar_position: 38
+sidebar_label: FUNCTION
+---
+
+# CREATE FUNCTION {#create-function}
+
+Creates a user defined function from a lambda expression. The expression must consist of function parameters, constants, operators, or other function calls.
+
+**Syntax**
+
+```sql
+CREATE FUNCTION name AS (parameter0, ...) -> expression
+```
+A function can have an arbitrary number of parameters.
+
+There are a few restrictions:
+
+-   The name of a function must be unique among user defined and system functions.
+-   Recursive functions are not allowed.
+-   All variables used by a function must be specified in its parameter list.
+
+If any restriction is violated then an exception is raised.
+
+**Example**
+
+Query:
+
+```sql
+CREATE FUNCTION linear_equation AS (x, k, b) -> k*x + b;
+SELECT number, linear_equation(number, 2, 1) FROM numbers(3);
+```
+
+Result:
+
+``` text
+┌─number─┬─plus(multiply(2, number), 1)─┐
+│      0 │                            1 │
+│      1 │                            3 │
+│      2 │                            5 │
+└────────┴──────────────────────────────┘
+```
+
+A [conditional function](../../../sql-reference/functions/conditional-functions.md) is called in a user defined function in the following query:
+
+```sql
+CREATE FUNCTION parity_str AS (n) -> if(n % 2, 'odd', 'even');
+SELECT number, parity_str(number) FROM numbers(3);
+```
+
+Result:
+
+``` text
+┌─number─┬─if(modulo(number, 2), 'odd', 'even')─┐
+│      0 │ even                                 │
+│      1 │ odd                                  │
+│      2 │ even                                 │
+└────────┴──────────────────────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/statements/create/index.md b/docs/en/reference/sql-reference/statements/create/index.md
new file mode 100644
index 00000000000..666a2c66d2f
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/create/index.md
@@ -0,0 +1,21 @@
+---
+sidebar_position: 34
+sidebar_label: CREATE
+---
+
+# CREATE Queries
+
+Create queries make a new entity of one of the following kinds:
+
+-   [DATABASE](../../../sql-reference/statements/create/database.md)
+-   [TABLE](../../../sql-reference/statements/create/table.md)
+-   [VIEW](../../../sql-reference/statements/create/view.md)
+-   [DICTIONARY](../../../sql-reference/statements/create/dictionary.md)
+-   [FUNCTION](../../../sql-reference/statements/create/function.md)
+-   [USER](../../../sql-reference/statements/create/user.md)
+-   [ROLE](../../../sql-reference/statements/create/role.md)
+-   [ROW POLICY](../../../sql-reference/statements/create/row-policy.md)
+-   [QUOTA](../../../sql-reference/statements/create/quota.md)
+-   [SETTINGS PROFILE](../../../sql-reference/statements/create/settings-profile.md)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/statements/create/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/statements/create/quota.md b/docs/en/reference/sql-reference/statements/create/quota.md
new file mode 100644
index 00000000000..931da165a73
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/create/quota.md
@@ -0,0 +1,39 @@
+---
+sidebar_position: 42
+sidebar_label: QUOTA
+---
+
+# CREATE QUOTA {#create-quota-statement}
+
+Creates a [quota](../../../operations/access-rights.md#quotas-management) that can be assigned to a user or a role.
+
+Syntax:
+
+``` sql
+CREATE QUOTA [IF NOT EXISTS | OR REPLACE] name [ON CLUSTER cluster_name]
+    [KEYED BY {user_name | ip_address | client_key | client_key,user_name | client_key,ip_address} | NOT KEYED]
+    [FOR [RANDOMIZED] INTERVAL number {second | minute | hour | day | week | month | quarter | year}
+        {MAX { {queries | query_selects | query_inserts | errors | result_rows | result_bytes | read_rows | read_bytes | execution_time} = number } [,...] |
+         NO LIMITS | TRACKING ONLY} [,...]]
+    [TO {role [,...] | ALL | ALL EXCEPT role [,...]}]
+```
+
+Keys `user_name`, `ip_address`, `client_key`, `client_key, user_name` and `client_key, ip_address` correspond to the fields in the [system.quotas](../../../operations/system-tables/quotas.md) table.
+
+Parameters `queries`, `query_selects`, `query_inserts`, `errors`, `result_rows`, `result_bytes`, `read_rows`, `read_bytes`, `execution_time` correspond to the fields in the [system.quotas_usage](../../../operations/system-tables/quotas_usage.md) table.
+
+`ON CLUSTER` clause allows creating quotas on a cluster, see [Distributed DDL](../../../sql-reference/distributed-ddl.md).
+
+**Examples**
+
+Limit the maximum number of queries for the current user with 123 queries in 15 months constraint:
+
+``` sql
+CREATE QUOTA qA FOR INTERVAL 15 month MAX queries = 123 TO CURRENT_USER;
+```
+
+For the default user limit the maximum execution time with half a second in 30 minutes, and limit the maximum number of queries with 321 and the maximum number of errors with 10 in 5 quaters:
+
+``` sql
+CREATE QUOTA qB FOR INTERVAL 30 minute MAX execution_time = 0.5, FOR INTERVAL 5 quarter MAX queries = 321, errors = 10 TO default;
+```
diff --git a/docs/en/reference/sql-reference/statements/create/role.md b/docs/en/reference/sql-reference/statements/create/role.md
new file mode 100644
index 00000000000..5f7db960f27
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/create/role.md
@@ -0,0 +1,47 @@
+---
+sidebar_position: 40
+sidebar_label: ROLE
+---
+
+# CREATE ROLE {#create-role-statement}
+
+Creates new [roles](../../../operations/access-rights.md#role-management). Role is a set of [privileges](../../../sql-reference/statements/grant.md#grant-privileges). A [user](../../../sql-reference/statements/create/user.md) assigned a role gets all the privileges of this role.
+
+Syntax:
+
+``` sql
+CREATE ROLE [IF NOT EXISTS | OR REPLACE] name1 [, name2 ...]
+    [SETTINGS variable [= value] [MIN [=] min_value] [MAX [=] max_value] [READONLY|WRITABLE] | PROFILE 'profile_name'] [,...]
+```
+
+## Managing Roles {#managing-roles}
+
+A user can be assigned multiple roles. Users can apply their assigned roles in arbitrary combinations by the [SET ROLE](../../../sql-reference/statements/set-role.md) statement. The final scope of privileges is a combined set of all the privileges of all the applied roles. If a user has privileges granted directly to it’s user account, they are also combined with the privileges granted by roles.
+
+User can have default roles which apply at user login. To set default roles, use the [SET DEFAULT ROLE](../../../sql-reference/statements/set-role.md#set-default-role-statement) statement or the [ALTER USER](../../../sql-reference/statements/alter/user.md#alter-user-statement) statement.
+
+To revoke a role, use the [REVOKE](../../../sql-reference/statements/revoke.md) statement.
+
+To delete role, use the [DROP ROLE](../../../sql-reference/statements/drop.md#drop-role-statement) statement. The deleted role is being automatically revoked from all the users and roles to which it was assigned.
+
+## Examples {#create-role-examples}
+
+``` sql
+CREATE ROLE accountant;
+GRANT SELECT ON db.* TO accountant;
+```
+
+This sequence of queries creates the role `accountant` that has the privilege of reading data from the `db` database.
+
+Assigning the role to the user `mira`:
+
+``` sql
+GRANT accountant TO mira;
+```
+
+After the role is assigned, the user can apply it and execute the allowed queries. For example:
+
+``` sql
+SET ROLE accountant;
+SELECT * FROM db.*;
+```
diff --git a/docs/en/reference/sql-reference/statements/create/row-policy.md b/docs/en/reference/sql-reference/statements/create/row-policy.md
new file mode 100644
index 00000000000..58b7b1e2cb9
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/create/row-policy.md
@@ -0,0 +1,90 @@
+---
+sidebar_position: 41
+sidebar_label: ROW POLICY
+---
+
+# CREATE ROW POLICY {#create-row-policy-statement}
+
+Creates a [row policy](../../../operations/access-rights.md#row-policy-management), i.e. a filter used to determine which rows a user can read from a table.
+
+:::warning    
+Row policies makes sense only for users with readonly access. If user can modify table or copy partitions between tables, it defeats the restrictions of row policies.
+:::
+
+Syntax:
+
+``` sql
+CREATE [ROW] POLICY [IF NOT EXISTS | OR REPLACE] policy_name1 [ON CLUSTER cluster_name1] ON [db1.]table1
+        [, policy_name2 [ON CLUSTER cluster_name2] ON [db2.]table2 ...]
+    [FOR SELECT] USING condition
+    [AS {PERMISSIVE | RESTRICTIVE}]
+    [TO {role1 [, role2 ...] | ALL | ALL EXCEPT role1 [, role2 ...]}]
+```
+
+## USING Clause {#create-row-policy-using}
+
+Allows to specify a condition to filter rows. An user will see a row if the condition is calculated to non-zero for the row.
+
+## TO Clause {#create-row-policy-to}
+
+In the section `TO` you can provide a list of users and roles this policy should work for. For example, `CREATE ROW POLICY ... TO accountant, john@localhost`.
+
+Keyword `ALL` means all the ClickHouse users including current user. Keyword `ALL EXCEPT` allow to exclude some users from the all users list, for example, `CREATE ROW POLICY ... TO ALL EXCEPT accountant, john@localhost`
+
+:::note    
+If there are no row policies defined for a table then any user can `SELECT` all the row from the table. Defining one or more row policies for the table makes the access to the table depending on the row policies no matter if those row policies are defined for the current user or not. For example, the following policy
+
+`CREATE ROW POLICY pol1 ON mydb.table1 USING b=1 TO mira, peter`
+
+forbids the users `mira` and `peter` to see the rows with `b != 1`, and any non-mentioned user (e.g., the user `paul`) will see no rows from `mydb.table1` at all.
+
+If that's not desirable it can't be fixed by adding one more row policy, like the following:
+
+`CREATE ROW POLICY pol2 ON mydb.table1 USING 1 TO ALL EXCEPT mira, peter`
+:::
+
+## AS Clause {#create-row-policy-as}
+
+It's allowed to have more than one policy enabled on the same table for the same user at the one time. So we need a way to combine the conditions from multiple policies.
+
+By default policies are combined using the boolean `OR` operator. For example, the following policies
+
+``` sql
+CREATE ROW POLICY pol1 ON mydb.table1 USING b=1 TO mira, peter
+CREATE ROW POLICY pol2 ON mydb.table1 USING c=2 TO peter, antonio
+```
+
+enables the user `peter` to see rows with either `b=1` or `c=2`.
+
+The `AS` clause specifies how policies should be combined with other policies. Policies can be either permissive or restrictive. By default policies are permissive, which means they are combined using the boolean `OR` operator.
+
+A policy can be defined as restrictive as an alternative. Restrictive policies are combined using the boolean `AND` operator.
+
+Here is the general formula:
+
+```
+row_is_visible = (one or more of the permissive policies' conditions are non-zero) AND
+                 (all of the restrictive policies's conditions are non-zero)
+```
+
+For example, the following policies
+
+``` sql
+CREATE ROW POLICY pol1 ON mydb.table1 USING b=1 TO mira, peter
+CREATE ROW POLICY pol2 ON mydb.table1 USING c=2 AS RESTRICTIVE TO peter, antonio
+```
+
+enables the user `peter` to see rows only if both `b=1` AND `c=2`.
+
+## ON CLUSTER Clause {#create-row-policy-on-cluster}
+
+Allows creating row policies on a cluster, see [Distributed DDL](../../../sql-reference/distributed-ddl.md).
+
+
+## Examples
+
+`CREATE ROW POLICY filter1 ON mydb.mytable USING a<1000 TO accountant, john@localhost`
+
+`CREATE ROW POLICY filter2 ON mydb.mytable USING a<1000 AND b=5 TO ALL EXCEPT mira`
+
+`CREATE ROW POLICY filter3 ON mydb.mytable USING 1 TO admin`
diff --git a/docs/en/reference/sql-reference/statements/create/settings-profile.md b/docs/en/reference/sql-reference/statements/create/settings-profile.md
new file mode 100644
index 00000000000..0cc633d9770
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/create/settings-profile.md
@@ -0,0 +1,26 @@
+---
+sidebar_position: 43
+sidebar_label: SETTINGS PROFILE
+---
+
+# CREATE SETTINGS PROFILE {#create-settings-profile-statement}
+
+Creates [settings profiles](../../../operations/access-rights.md#settings-profiles-management) that can be assigned to a user or a role.
+
+Syntax:
+
+``` sql
+CREATE SETTINGS PROFILE [IF NOT EXISTS | OR REPLACE] TO name1 [ON CLUSTER cluster_name1]
+        [, name2 [ON CLUSTER cluster_name2] ...]
+    [SETTINGS variable [= value] [MIN [=] min_value] [MAX [=] max_value] [READONLY|WRITABLE] | INHERIT 'profile_name'] [,...]
+```
+
+`ON CLUSTER` clause allows creating settings profiles on a cluster, see [Distributed DDL](../../../sql-reference/distributed-ddl.md).
+
+## Example {#create-settings-profile-syntax}
+
+Create the `max_memory_usage_profile` settings profile with value and constraints for the `max_memory_usage` setting and assign it to user `robin`:
+
+``` sql
+CREATE SETTINGS PROFILE max_memory_usage_profile SETTINGS max_memory_usage = 100000001 MIN 90000000 MAX 110000000 TO robin
+```
diff --git a/docs/en/reference/sql-reference/statements/create/table.md b/docs/en/reference/sql-reference/statements/create/table.md
new file mode 100644
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+---
+sidebar_position: 36
+sidebar_label: TABLE
+---
+
+# CREATE TABLE {#create-table-query}
+
+Creates a new table. This query can have various syntax forms depending on a use case.
+
+By default, tables are created only on the current server. Distributed DDL queries are implemented as `ON CLUSTER` clause, which is [described separately](../../../sql-reference/distributed-ddl.md).
+
+## Syntax Forms {#syntax-forms}
+
+### With Explicit Schema {#with-explicit-schema}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [NULL|NOT NULL] [DEFAULT|MATERIALIZED|EPHEMERAL|ALIAS expr1] [compression_codec] [TTL expr1],
+    name2 [type2] [NULL|NOT NULL] [DEFAULT|MATERIALIZED|EPHEMERAL|ALIAS expr2] [compression_codec] [TTL expr2],
+    ...
+) ENGINE = engine
+```
+
+Creates a table named `table_name` in the `db` database or the current database if `db` is not set, with the structure specified in brackets and the `engine` engine.
+The structure of the table is a list of column descriptions, secondary indexes and constraints . If [primary key](#primary-key) is supported by the engine, it will be indicated as parameter for the table engine.
+
+A column description is `name type` in the simplest case. Example: `RegionID UInt32`.
+
+Expressions can also be defined for default values (see below).
+
+If necessary, primary key can be specified, with one or more key expressions.
+
+### With a Schema Similar to Other Table {#with-a-schema-similar-to-other-table}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name AS [db2.]name2 [ENGINE = engine]
+```
+
+Creates a table with the same structure as another table. You can specify a different engine for the table. If the engine is not specified, the same engine will be used as for the `db2.name2` table.
+
+### From a Table Function {#from-a-table-function}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name AS table_function()
+```
+
+Creates a table with the same result as that of the [table function](../../../sql-reference/table-functions/index.md#table-functions) specified. The created table will also work in the same way as the corresponding table function that was specified.
+
+### From SELECT query {#from-select-query}
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name[(name1 [type1], name2 [type2], ...)] ENGINE = engine AS SELECT ...
+```
+
+Creates a table with a structure like the result of the `SELECT` query, with the `engine` engine, and fills it with data from `SELECT`. Also you can explicitly specify columns description.
+
+If the table already exists and `IF NOT EXISTS` is specified, the query won’t do anything.
+
+There can be other clauses after the `ENGINE` clause in the query. See detailed documentation on how to create tables in the descriptions of [table engines](../../../engines/table-engines/index.md#table_engines).
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE t1 (x String) ENGINE = Memory AS SELECT 1;
+SELECT x, toTypeName(x) FROM t1;
+```
+
+Result:
+
+```text
+┌─x─┬─toTypeName(x)─┐
+│ 1 │ String        │
+└───┴───────────────┘
+```
+
+## NULL Or NOT NULL Modifiers {#null-modifiers}
+
+`NULL` and `NOT NULL` modifiers after data type in column definition allow or do not allow it to be [Nullable](../../../sql-reference/data-types/nullable.md#data_type-nullable).
+
+If the type is not `Nullable` and if `NULL` is specified, it will be treated as `Nullable`; if `NOT NULL` is specified, then no. For example, `INT NULL` is the same as `Nullable(INT)`. If the type is `Nullable` and `NULL` or `NOT NULL` modifiers are specified, the exception will be thrown.
+
+See also [data_type_default_nullable](../../../operations/settings/settings.md#data_type_default_nullable) setting.
+
+## Default Values {#create-default-values}
+
+The column description can specify an expression for a default value, in one of the following ways: `DEFAULT expr`, `MATERIALIZED expr`, `ALIAS expr`.
+
+Example: `URLDomain String DEFAULT domain(URL)`.
+
+If an expression for the default value is not defined, the default values will be set to zeros for numbers, empty strings for strings, empty arrays for arrays, and `1970-01-01` for dates or zero unix timestamp for DateTime, NULL for Nullable.
+
+If the default expression is defined, the column type is optional. If there isn’t an explicitly defined type, the default expression type is used. Example: `EventDate DEFAULT toDate(EventTime)` – the ‘Date’ type will be used for the ‘EventDate’ column.
+
+If the data type and default expression are defined explicitly, this expression will be cast to the specified type using type casting functions. Example: `Hits UInt32 DEFAULT 0` means the same thing as `Hits UInt32 DEFAULT toUInt32(0)`.
+
+Default expressions may be defined as an arbitrary expression from table constants and columns. When creating and changing the table structure, it checks that expressions do not contain loops. For INSERT, it checks that expressions are resolvable – that all columns they can be calculated from have been passed.
+
+### DEFAULT {#default}
+
+`DEFAULT expr`
+
+Normal default value. If the INSERT query does not specify the corresponding column, it will be filled in by computing the corresponding expression.
+
+### MATERIALIZED {#materialized}
+
+`MATERIALIZED expr`
+
+Materialized expression. Such a column can’t be specified for INSERT, because it is always calculated.
+For an INSERT without a list of columns, these columns are not considered.
+In addition, this column is not substituted when using an asterisk in a SELECT query. This is to preserve the invariant that the dump obtained using `SELECT *` can be inserted back into the table using INSERT without specifying the list of columns.
+
+### EPHEMERAL {#ephemeral}
+
+`EPHEMERAL [expr]`
+
+Ephemeral column. Such a column isn't stored in the table and cannot be SELECTed, but can be referenced in the defaults of CREATE statement. If `expr` is omitted type for column is required.
+INSERT without list of columns will skip such column, so SELECT/INSERT invariant is preserved -  the dump obtained using `SELECT *` can be inserted back into the table using INSERT without specifying the list of columns.
+
+### ALIAS {#alias}
+
+`ALIAS expr`
+
+Synonym. Such a column isn’t stored in the table at all.
+Its values can’t be inserted in a table, and it is not substituted when using an asterisk in a SELECT query.
+It can be used in SELECTs if the alias is expanded during query parsing.
+
+When using the ALTER query to add new columns, old data for these columns is not written. Instead, when reading old data that does not have values for the new columns, expressions are computed on the fly by default. However, if running the expressions requires different columns that are not indicated in the query, these columns will additionally be read, but only for the blocks of data that need it.
+
+If you add a new column to a table but later change its default expression, the values used for old data will change (for data where values were not stored on the disk). Note that when running background merges, data for columns that are missing in one of the merging parts is written to the merged part.
+
+It is not possible to set default values for elements in nested data structures.
+
+## Primary Key {#primary-key}
+
+You can define a [primary key](../../../engines/table-engines/mergetree-family/mergetree.md#primary-keys-and-indexes-in-queries) when creating a table. Primary key can be specified in two ways:
+
+- Inside the column list
+
+``` sql
+CREATE TABLE db.table_name
+(
+    name1 type1, name2 type2, ...,
+    PRIMARY KEY(expr1[, expr2,...])]
+)
+ENGINE = engine;
+```
+
+- Outside the column list
+
+``` sql
+CREATE TABLE db.table_name
+(
+    name1 type1, name2 type2, ...
+)
+ENGINE = engine
+PRIMARY KEY(expr1[, expr2,...]);
+```
+
+:::warning    
+You can't combine both ways in one query.
+:::
+
+## Constraints {#constraints}
+
+Along with columns descriptions constraints could be defined:
+
+``` sql
+CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1] [compression_codec] [TTL expr1],
+    ...
+    CONSTRAINT constraint_name_1 CHECK boolean_expr_1,
+    ...
+) ENGINE = engine
+```
+
+`boolean_expr_1` could by any boolean expression. If constraints are defined for the table, each of them will be checked for every row in `INSERT` query. If any constraint is not satisfied — server will raise an exception with constraint name and checking expression.
+
+Adding large amount of constraints can negatively affect performance of big `INSERT` queries.
+
+## TTL Expression {#ttl-expression}
+
+Defines storage time for values. Can be specified only for MergeTree-family tables. For the detailed description, see [TTL for columns and tables](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl).
+
+## Column Compression Codecs {#codecs}
+
+By default, ClickHouse applies the `lz4` compression method. For `MergeTree`-engine family you can change the default compression method in the [compression](../../../operations/server-configuration-parameters/settings.md#server-settings-compression) section of a server configuration.
+
+You can also define the compression method for each individual column in the `CREATE TABLE` query.
+
+``` sql
+CREATE TABLE codec_example
+(
+    dt Date CODEC(ZSTD),
+    ts DateTime CODEC(LZ4HC),
+    float_value Float32 CODEC(NONE),
+    double_value Float64 CODEC(LZ4HC(9)),
+    value Float32 CODEC(Delta, ZSTD)
+)
+ENGINE = <Engine>
+...
+```
+
+The `Default` codec can be specified to reference default compression which may depend on different settings (and properties of data) in runtime.
+Example: `value UInt64 CODEC(Default)` — the same as lack of codec specification.
+
+Also you can remove current CODEC from the column and use default compression from config.xml:
+
+``` sql
+ALTER TABLE codec_example MODIFY COLUMN float_value CODEC(Default);
+```
+
+Codecs can be combined in a pipeline, for example, `CODEC(Delta, Default)`.
+
+:::warning    
+You can’t decompress ClickHouse database files with external utilities like `lz4`. Instead, use the special [clickhouse-compressor](https://github.com/ClickHouse/ClickHouse/tree/master/programs/compressor) utility.
+:::
+
+Compression is supported for the following table engines:
+
+-   [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md) family. Supports column compression codecs and selecting the default compression method by [compression](../../../operations/server-configuration-parameters/settings.md#server-settings-compression) settings.
+-   [Log](../../../engines/table-engines/log-family/index.md) family. Uses the `lz4` compression method by default and supports column compression codecs.
+-   [Set](../../../engines/table-engines/special/set.md). Only supported the default compression.
+-   [Join](../../../engines/table-engines/special/join.md). Only supported the default compression.
+
+ClickHouse supports general purpose codecs and specialized codecs.
+
+### General Purpose Codecs {#create-query-general-purpose-codecs}
+
+Codecs:
+
+-   `NONE` — No compression.
+-   `LZ4` — Lossless [data compression algorithm](https://github.com/lz4/lz4) used by default. Applies LZ4 fast compression.
+-   `LZ4HC[(level)]` — LZ4 HC (high compression) algorithm with configurable level. Default level: 9. Setting `level <= 0` applies the default level. Possible levels: \[1, 12\]. Recommended level range: \[4, 9\].
+-   `ZSTD[(level)]` — [ZSTD compression algorithm](https://en.wikipedia.org/wiki/Zstandard) with configurable `level`. Possible levels: \[1, 22\]. Default value: 1.
+
+High compression levels are useful for asymmetric scenarios, like compress once, decompress repeatedly. Higher levels mean better compression and higher CPU usage.
+
+### Specialized Codecs {#specialized-codecs}
+
+These codecs are designed to make compression more effective by using specific features of data. Some of these codecs do not compress data themself. Instead, they prepare the data for a common purpose codec, which compresses it better than without this preparation.
+
+Specialized codecs:
+
+-   `Delta(delta_bytes)` — Compression approach in which raw values are replaced by the difference of two neighboring values, except for the first value that stays unchanged. Up to `delta_bytes` are used for storing delta values, so `delta_bytes` is the maximum size of raw values. Possible `delta_bytes` values: 1, 2, 4, 8. The default value for `delta_bytes` is `sizeof(type)` if equal to 1, 2, 4, or 8. In all other cases, it’s 1.
+-   `DoubleDelta` — Calculates delta of deltas and writes it in compact binary form. Optimal compression rates are achieved for monotonic sequences with a constant stride, such as time series data. Can be used with any fixed-width type. Implements the algorithm used in Gorilla TSDB, extending it to support 64-bit types. Uses 1 extra bit for 32-byte deltas: 5-bit prefixes instead of 4-bit prefixes. For additional information, see Compressing Time Stamps in [Gorilla: A Fast, Scalable, In-Memory Time Series Database](http://www.vldb.org/pvldb/vol8/p1816-teller.pdf).
+-   `Gorilla` — Calculates XOR between current and previous value and writes it in compact binary form. Efficient when storing a series of floating point values that change slowly, because the best compression rate is achieved when neighboring values are binary equal. Implements the algorithm used in Gorilla TSDB, extending it to support 64-bit types. For additional information, see Compressing Values in [Gorilla: A Fast, Scalable, In-Memory Time Series Database](http://www.vldb.org/pvldb/vol8/p1816-teller.pdf).
+-   `T64` — Compression approach that crops unused high bits of values in integer data types (including `Enum`, `Date` and `DateTime`). At each step of its algorithm, codec takes a block of 64 values, puts them into 64x64 bit matrix, transposes it, crops the unused bits of values and returns the rest as a sequence. Unused bits are the bits, that do not differ between maximum and minimum values in the whole data part for which the compression is used.
+
+`DoubleDelta` and `Gorilla` codecs are used in Gorilla TSDB as the components of its compressing algorithm. Gorilla approach is effective in scenarios when there is a sequence of slowly changing values with their timestamps. Timestamps are effectively compressed by the `DoubleDelta` codec, and values are effectively compressed by the `Gorilla` codec. For example, to get an effectively stored table, you can create it in the following configuration:
+
+``` sql
+CREATE TABLE codec_example
+(
+    timestamp DateTime CODEC(DoubleDelta),
+    slow_values Float32 CODEC(Gorilla)
+)
+ENGINE = MergeTree()
+```
+
+### Encryption Codecs {#create-query-encryption-codecs}
+
+These codecs don't actually compress data, but instead encrypt data on disk. These are only available when an encryption key is specified by [encryption](../../../operations/server-configuration-parameters/settings.md#server-settings-encryption) settings. Note that encryption only makes sense at the end of codec pipelines, because encrypted data usually can't be compressed in any meaningful way.
+
+Encryption codecs:
+
+-   `CODEC('AES-128-GCM-SIV')` — Encrypts data with AES-128 in [RFC 8452](https://tools.ietf.org/html/rfc8452) GCM-SIV mode. 
+
+-   `CODEC('AES-256-GCM-SIV')` — Encrypts data with AES-256 in GCM-SIV mode. 
+
+These codecs use a fixed nonce and encryption is therefore deterministic. This makes it compatible with deduplicating engines such as [ReplicatedMergeTree](../../../engines/table-engines/mergetree-family/replication.md) but has a weakness: when the same data block is encrypted twice, the resulting ciphertext will be exactly the same so an adversary who can read the disk can see this equivalence (although only the equivalence, without getting its content).
+
+:::warning    
+Most engines including the "*MergeTree" family create index files on disk without applying codecs. This means plaintext will appear on disk if an encrypted column is indexed.
+:::
+
+:::warning    
+If you perform a SELECT query mentioning a specific value in an encrypted column (such as in its WHERE clause), the value may appear in [system.query_log](../../../operations/system-tables/query_log.md). You may want to disable the logging.
+:::
+
+**Example**
+
+```sql
+CREATE TABLE mytable 
+(
+    x String Codec(AES_128_GCM_SIV)
+) 
+ENGINE = MergeTree ORDER BY x;
+```
+
+:::note    
+If compression needs to be applied, it must be explicitly specified. Otherwise, only encryption will be applied to data.
+:::
+
+**Example**
+
+```sql
+CREATE TABLE mytable 
+(
+    x String Codec(Delta, LZ4, AES_128_GCM_SIV)
+) 
+ENGINE = MergeTree ORDER BY x;
+```
+
+## Temporary Tables {#temporary-tables}
+
+ClickHouse supports temporary tables which have the following characteristics:
+
+-   Temporary tables disappear when the session ends, including if the connection is lost.
+-   A temporary table uses the Memory engine only.
+-   The DB can’t be specified for a temporary table. It is created outside of databases.
+-   Impossible to create a temporary table with distributed DDL query on all cluster servers (by using `ON CLUSTER`): this table exists only in the current session.
+-   If a temporary table has the same name as another one and a query specifies the table name without specifying the DB, the temporary table will be used.
+-   For distributed query processing, temporary tables used in a query are passed to remote servers.
+
+To create a temporary table, use the following syntax:
+
+``` sql
+CREATE TEMPORARY TABLE [IF NOT EXISTS] table_name
+(
+    name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1],
+    name2 [type2] [DEFAULT|MATERIALIZED|ALIAS expr2],
+    ...
+)
+```
+
+In most cases, temporary tables are not created manually, but when using external data for a query, or for distributed `(GLOBAL) IN`. For more information, see the appropriate sections
+
+It’s possible to use tables with [ENGINE = Memory](../../../engines/table-engines/special/memory.md) instead of temporary tables.
+
+## REPLACE TABLE {#replace-table-query}
+
+'REPLACE' query allows you to update the table atomically.
+
+:::note    
+This query is supported only for [Atomic](../../../engines/database-engines/atomic.md) database engine.
+:::
+
+If you need to delete some data from a table, you can create a new table and fill it with a `SELECT` statement that does not retrieve unwanted data, then drop the old table and rename the new one:
+
+```sql
+CREATE TABLE myNewTable AS myOldTable;
+INSERT INTO myNewTable SELECT * FROM myOldTable WHERE CounterID <12345;
+DROP TABLE myOldTable;
+RENAME TABLE myNewTable TO myOldTable;
+```
+
+Instead of above, you can use the following:
+
+```sql
+REPLACE TABLE myOldTable SELECT * FROM myOldTable WHERE CounterID <12345;
+```
+
+### Syntax
+
+``` sql
+{CREATE [OR REPLACE] | REPLACE} TABLE [db.]table_name
+```
+
+All syntax forms for `CREATE` query also work for this query. `REPLACE` for a non-existent table will cause an error.
+
+### Examples:
+
+Consider the table:
+
+```sql
+CREATE DATABASE base ENGINE = Atomic;
+CREATE OR REPLACE TABLE base.t1 (n UInt64, s String) ENGINE = MergeTree ORDER BY n;
+INSERT INTO base.t1 VALUES (1, 'test');
+SELECT * FROM base.t1;
+```
+
+```text
+┌─n─┬─s────┐
+│ 1 │ test │
+└───┴──────┘
+```
+
+Using `REPLACE` query to clear all data:
+
+```sql
+CREATE OR REPLACE TABLE base.t1 (n UInt64, s Nullable(String)) ENGINE = MergeTree ORDER BY n;
+INSERT INTO base.t1 VALUES (2, null);
+SELECT * FROM base.t1;
+```
+
+```text
+┌─n─┬─s──┐
+│ 2 │ \N │
+└───┴────┘
+```
+
+Using `REPLACE` query to change table structure:
+
+```sql
+REPLACE TABLE base.t1 (n UInt64) ENGINE = MergeTree ORDER BY n;
+INSERT INTO base.t1 VALUES (3);
+SELECT * FROM base.t1;
+```
+
+```text
+┌─n─┐
+│ 3 │
+└───┘
+```
+
+## COMMENT Clause {#comment-table}
+
+You can add a comment to the table when you creating it.
+
+:::note    
+The comment is supported for all table engines except [Kafka](../../../engines/table-engines/integrations/kafka.md), [RabbitMQ](../../../engines/table-engines/integrations/rabbitmq.md) and [EmbeddedRocksDB](../../../engines/table-engines/integrations/embedded-rocksdb.md).
+:::
+
+
+**Syntax**
+
+``` sql
+CREATE TABLE db.table_name
+(
+    name1 type1, name2 type2, ...
+)
+ENGINE = engine
+COMMENT 'Comment'
+```
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE t1 (x String) ENGINE = Memory COMMENT 'The temporary table';
+SELECT name, comment FROM system.tables WHERE name = 't1';
+```
+
+Result:
+
+```text
+┌─name─┬─comment─────────────┐
+│ t1   │ The temporary table │
+└──────┴─────────────────────┘
+```
diff --git a/docs/en/reference/sql-reference/statements/create/user.md b/docs/en/reference/sql-reference/statements/create/user.md
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+---
+sidebar_position: 39
+sidebar_label: USER
+---
+
+# CREATE USER {#create-user-statement}
+
+Creates [user accounts](../../../operations/access-rights.md#user-account-management).
+
+Syntax:
+
+``` sql
+CREATE USER [IF NOT EXISTS | OR REPLACE] name1 [ON CLUSTER cluster_name1]
+        [, name2 [ON CLUSTER cluster_name2] ...]
+    [NOT IDENTIFIED | IDENTIFIED {[WITH {no_password | plaintext_password | sha256_password | sha256_hash | double_sha1_password | double_sha1_hash}] BY {'password' | 'hash'}} | {WITH ldap SERVER 'server_name'} | {WITH kerberos [REALM 'realm']}]
+    [HOST {LOCAL | NAME 'name' | REGEXP 'name_regexp' | IP 'address' | LIKE 'pattern'} [,...] | ANY | NONE]
+    [DEFAULT ROLE role [,...]]
+    [DEFAULT DATABASE database | NONE]
+    [GRANTEES {user | role | ANY | NONE} [,...] [EXCEPT {user | role} [,...]]]
+    [SETTINGS variable [= value] [MIN [=] min_value] [MAX [=] max_value] [READONLY | WRITABLE] | PROFILE 'profile_name'] [,...]
+```
+
+`ON CLUSTER` clause allows creating users on a cluster, see [Distributed DDL](../../../sql-reference/distributed-ddl.md).
+
+## Identification {#identification}
+
+There are multiple ways of user identification:
+
+-   `IDENTIFIED WITH no_password`
+-   `IDENTIFIED WITH plaintext_password BY 'qwerty'`
+-   `IDENTIFIED WITH sha256_password BY 'qwerty'` or `IDENTIFIED BY 'password'`
+-   `IDENTIFIED WITH sha256_hash BY 'hash'`
+-   `IDENTIFIED WITH double_sha1_password BY 'qwerty'`
+-   `IDENTIFIED WITH double_sha1_hash BY 'hash'`
+-   `IDENTIFIED WITH ldap SERVER 'server_name'`
+-   `IDENTIFIED WITH kerberos` or `IDENTIFIED WITH kerberos REALM 'realm'`
+
+## User Host {#user-host}
+
+User host is a host from which a connection to ClickHouse server could be established. The host can be specified in the `HOST` query section in the following ways:
+
+-   `HOST IP 'ip_address_or_subnetwork'` — User can connect to ClickHouse server only from the specified IP address or a [subnetwork](https://en.wikipedia.org/wiki/Subnetwork). Examples: `HOST IP '192.168.0.0/16'`, `HOST IP '2001:DB8::/32'`. For use in production, only specify `HOST IP` elements (IP addresses and their masks), since using `host` and `host_regexp` might cause extra latency.
+-   `HOST ANY` — User can connect from any location. This is a default option.
+-   `HOST LOCAL` — User can connect only locally.
+-   `HOST NAME 'fqdn'` — User host can be specified as FQDN. For example, `HOST NAME 'mysite.com'`.
+-   `HOST REGEXP 'regexp'` — You can use [pcre](http://www.pcre.org/) regular expressions when specifying user hosts. For example, `HOST REGEXP '.*\.mysite\.com'`.
+-   `HOST LIKE 'template'` — Allows you to use the [LIKE](../../../sql-reference/functions/string-search-functions.md#function-like) operator to filter the user hosts. For example, `HOST LIKE '%'` is equivalent to `HOST ANY`, `HOST LIKE '%.mysite.com'` filters all the hosts in the `mysite.com` domain.
+
+Another way of specifying host is to use `@` syntax following the username. Examples:
+
+-   `CREATE USER mira@'127.0.0.1'` — Equivalent to the `HOST IP` syntax.
+-   `CREATE USER mira@'localhost'` — Equivalent to the `HOST LOCAL` syntax.
+-   `CREATE USER mira@'192.168.%.%'` — Equivalent to the `HOST LIKE` syntax.
+
+:::warning    
+ClickHouse treats `user_name@'address'` as a username as a whole. Thus, technically you can create multiple users with the same `user_name` and different constructions after `@`. However, we do not recommend to do so.
+:::
+
+## GRANTEES Clause {#grantees}
+
+Specifies users or roles which are allowed to receive [privileges](../../../sql-reference/statements/grant.md#grant-privileges) from this user on the condition this user has also all required access granted with [GRANT OPTION](../../../sql-reference/statements/grant.md#grant-privigele-syntax). Options of the `GRANTEES` clause:
+
+-   `user` — Specifies a user this user can grant privileges to.
+-   `role` — Specifies a role this user can grant privileges to.
+-   `ANY` — This user can grant privileges to anyone. It's the default setting.
+-   `NONE` — This user can grant privileges to none.
+
+You can exclude any user or role by using the `EXCEPT` expression. For example, `CREATE USER user1 GRANTEES ANY EXCEPT user2`. It means if `user1` has some privileges granted with `GRANT OPTION` it will be able to grant those privileges to anyone except `user2`.
+
+## Examples {#create-user-examples}
+
+Create the user account `mira` protected by the password `qwerty`:
+
+``` sql
+CREATE USER mira HOST IP '127.0.0.1' IDENTIFIED WITH sha256_password BY 'qwerty';
+```
+
+`mira` should start client app at the host where the ClickHouse server runs.
+
+Create the user account `john`, assign roles to it and make this roles default:
+
+``` sql
+CREATE USER john DEFAULT ROLE role1, role2;
+```
+
+Create the user account `john` and make all his future roles default:
+
+``` sql
+CREATE USER john DEFAULT ROLE ALL;
+```
+
+When some role is assigned to `john` in the future, it will become default automatically.
+
+Create the user account `john` and make all his future roles default excepting `role1` and `role2`:
+
+``` sql
+CREATE USER john DEFAULT ROLE ALL EXCEPT role1, role2;
+```
+
+Create the user account `john` and allow him to grant his privileges to the user with `jack` account:
+
+``` sql
+CREATE USER john GRANTEES jack;
+```
diff --git a/docs/en/reference/sql-reference/statements/create/view.md b/docs/en/reference/sql-reference/statements/create/view.md
new file mode 100644
index 00000000000..e31d1b4473f
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/create/view.md
@@ -0,0 +1,365 @@
+---
+sidebar_position: 37
+sidebar_label: VIEW
+---
+
+# CREATE VIEW {#create-view}
+
+Creates a new view. Views can be [normal](#normal), [materialized](#materialized), [live](#live-view), and [window](#window-view) (live view and window view are experimental features).
+
+## Normal View {#normal}
+
+Syntax:
+
+``` sql
+CREATE [OR REPLACE] VIEW [IF NOT EXISTS] [db.]table_name [ON CLUSTER] AS SELECT ...
+```
+
+Normal views do not store any data. They just perform a read from another table on each access. In other words, a normal view is nothing more than a saved query. When reading from a view, this saved query is used as a subquery in the [FROM](../../../sql-reference/statements/select/from.md) clause.
+
+As an example, assume you’ve created a view:
+
+``` sql
+CREATE VIEW view AS SELECT ...
+```
+
+and written a query:
+
+``` sql
+SELECT a, b, c FROM view
+```
+
+This query is fully equivalent to using the subquery:
+
+``` sql
+SELECT a, b, c FROM (SELECT ...)
+```
+
+## Materialized View {#materialized}
+
+``` sql
+CREATE MATERIALIZED VIEW [IF NOT EXISTS] [db.]table_name [ON CLUSTER] [TO[db.]name] [ENGINE = engine] [POPULATE] AS SELECT ...
+```
+
+Materialized views store data transformed by the corresponding [SELECT](../../../sql-reference/statements/select/index.md) query.
+
+When creating a materialized view without `TO [db].[table]`, you must specify `ENGINE` – the table engine for storing data.
+
+When creating a materialized view with `TO [db].[table]`, you must not use `POPULATE`.
+
+A materialized view is implemented as follows: when inserting data to the table specified in `SELECT`, part of the inserted data is converted by this `SELECT` query, and the result is inserted in the view.
+
+:::note    
+Materialized views in ClickHouse use **column names** instead of column order during insertion into destination table. If some column names are not present in the `SELECT` query result, ClickHouse uses a default value, even if the column is not [Nullable](../../data-types/nullable.md). A safe practice would be to add aliases for every column when using Materialized views.
+
+Materialized views in ClickHouse are implemented more like insert triggers. If there’s some aggregation in the view query, it’s applied only to the batch of freshly inserted data. Any changes to existing data of source table (like update, delete, drop partition, etc.) does not change the materialized view.
+:::
+
+If you specify `POPULATE`, the existing table data is inserted into the view when creating it, as if making a `CREATE TABLE ... AS SELECT ...` . Otherwise, the query contains only the data inserted in the table after creating the view. We **do not recommend** using `POPULATE`, since data inserted in the table during the view creation will not be inserted in it.
+
+A `SELECT` query can contain `DISTINCT`, `GROUP BY`, `ORDER BY`, `LIMIT`. Note that the corresponding conversions are performed independently on each block of inserted data. For example, if `GROUP BY` is set, data is aggregated during insertion, but only within a single packet of inserted data. The data won’t be further aggregated. The exception is when using an `ENGINE` that independently performs data aggregation, such as `SummingMergeTree`.
+
+The execution of [ALTER](../../../sql-reference/statements/alter/view.md) queries on materialized views has limitations, so they might be inconvenient. If the materialized view uses the construction `TO [db.]name`, you can `DETACH` the view, run `ALTER` for the target table, and then `ATTACH` the previously detached (`DETACH`) view.
+
+Note that materialized view is influenced by [optimize_on_insert](../../../operations/settings/settings.md#optimize-on-insert) setting. The data is merged before the insertion into a view.
+
+Views look the same as normal tables. For example, they are listed in the result of the `SHOW TABLES` query.
+
+To delete a view, use [DROP VIEW](../../../sql-reference/statements/drop.md#drop-view). Although `DROP TABLE` works for VIEWs as well.
+
+## Live View [Experimental] {#live-view}
+
+:::note    
+This is an experimental feature that may change in backwards-incompatible ways in the future releases. Enable usage of live views and `WATCH` query using [allow_experimental_live_view](../../../operations/settings/settings.md#allow-experimental-live-view) setting. Input the command `set allow_experimental_live_view = 1`.
+:::
+
+```sql
+CREATE LIVE VIEW [IF NOT EXISTS] [db.]table_name [WITH [TIMEOUT [value_in_sec] [AND]] [REFRESH [value_in_sec]]] AS SELECT ...
+```
+
+Live views store result of the corresponding [SELECT](../../../sql-reference/statements/select/index.md) query and are updated any time the result of the query changes. Query result as well as partial result needed to combine with new data are stored in memory providing increased performance for repeated queries. Live views can provide push notifications when query result changes using the [WATCH](../../../sql-reference/statements/watch.md) query.
+
+Live views are triggered by insert into the innermost table specified in the query.
+
+Live views work similarly to how a query in a distributed table works. But instead of combining partial results from different servers they combine partial result from current data with partial result from the new data. When a live view query includes a subquery then the cached partial result is only stored for the innermost subquery.
+
+:::info    
+- [Table function](../../../sql-reference/table-functions/index.md) is not supported as the innermost table.
+- Tables that do not have inserts such as a [dictionary](../../../sql-reference/dictionaries/index.md), [system table](../../../operations/system-tables/index.md), a [normal view](#normal), or a [materialized view](#materialized) will not trigger a live view.
+- Only queries where one can combine partial result from the old data plus partial result from the new data will work. Live view will not work for queries that require the complete data set to compute the final result or aggregations where the state of the aggregation must be preserved.
+- Does not work with replicated or distributed tables where inserts are performed on different nodes.
+- Can't be triggered by multiple tables.
+
+See [WITH REFRESH](#live-view-with-refresh) to force periodic updates of a live view that in some cases can be used as a workaround.
+:::
+
+### Monitoring Live View Changes {#live-view-monitoring}
+
+You can monitor changes in the `LIVE VIEW` query result using [WATCH](../../../sql-reference/statements/watch.md) query.
+
+```sql
+WATCH [db.]live_view
+```
+
+**Example:**
+
+```sql
+CREATE TABLE mt (x Int8) Engine = MergeTree ORDER BY x;
+CREATE LIVE VIEW lv AS SELECT sum(x) FROM mt;
+```
+Watch a live view while doing a parallel insert into the source table.
+
+```sql
+WATCH lv;
+```
+
+```bash
+┌─sum(x)─┬─_version─┐
+│      1 │        1 │
+└────────┴──────────┘
+┌─sum(x)─┬─_version─┐
+│      3 │        2 │
+└────────┴──────────┘
+┌─sum(x)─┬─_version─┐
+│      6 │        3 │
+└────────┴──────────┘
+```
+
+```sql
+INSERT INTO mt VALUES (1);
+INSERT INTO mt VALUES (2);
+INSERT INTO mt VALUES (3);
+```
+
+Or add [EVENTS](../../../sql-reference/statements/watch.md#events-clause) clause to just get change events.
+
+```sql
+WATCH [db.]live_view EVENTS;
+```
+
+**Example:**
+
+```sql
+WATCH lv EVENTS;
+```
+
+```bash
+┌─version─┐
+│       1 │
+└─────────┘
+┌─version─┐
+│       2 │
+└─────────┘
+┌─version─┐
+│       3 │
+└─────────┘
+```
+
+You can execute [SELECT](../../../sql-reference/statements/select/index.md) query on a live view in the same way as for any regular view or a table. If the query result is cached it will return the result immediately without running the stored query on the underlying tables.
+
+```sql
+SELECT * FROM [db.]live_view WHERE ...
+```
+
+### Force Live View Refresh {#live-view-alter-refresh}
+
+You can force live view refresh using the `ALTER LIVE VIEW [db.]table_name REFRESH` statement.
+
+### WITH TIMEOUT Clause {#live-view-with-timeout}
+
+When a live view is created with a `WITH TIMEOUT` clause then the live view will be dropped automatically after the specified number of seconds elapse since the end of the last [WATCH](../../../sql-reference/statements/watch.md) query that was watching the live view.
+
+```sql
+CREATE LIVE VIEW [db.]table_name WITH TIMEOUT [value_in_sec] AS SELECT ...
+```
+
+If the timeout value is not specified then the value specified by the [temporary_live_view_timeout](../../../operations/settings/settings.md#temporary-live-view-timeout) setting is used.
+
+**Example:**
+
+```sql
+CREATE TABLE mt (x Int8) Engine = MergeTree ORDER BY x;
+CREATE LIVE VIEW lv WITH TIMEOUT 15 AS SELECT sum(x) FROM mt;
+```
+
+### WITH REFRESH Clause {#live-view-with-refresh}
+
+When a live view is created with a `WITH REFRESH` clause then it will be automatically refreshed after the specified number of seconds elapse since the last refresh or trigger.
+
+```sql
+CREATE LIVE VIEW [db.]table_name WITH REFRESH [value_in_sec] AS SELECT ...
+```
+
+If the refresh value is not specified then the value specified by the [periodic_live_view_refresh](../../../operations/settings/settings.md#periodic-live-view-refresh) setting is used.
+
+**Example:**
+
+```sql
+CREATE LIVE VIEW lv WITH REFRESH 5 AS SELECT now();
+WATCH lv
+```
+
+```bash
+┌───────────────now()─┬─_version─┐
+│ 2021-02-21 08:47:05 │        1 │
+└─────────────────────┴──────────┘
+┌───────────────now()─┬─_version─┐
+│ 2021-02-21 08:47:10 │        2 │
+└─────────────────────┴──────────┘
+┌───────────────now()─┬─_version─┐
+│ 2021-02-21 08:47:15 │        3 │
+└─────────────────────┴──────────┘
+```
+
+You can combine `WITH TIMEOUT` and `WITH REFRESH` clauses using an `AND` clause.
+
+```sql
+CREATE LIVE VIEW [db.]table_name WITH TIMEOUT [value_in_sec] AND REFRESH [value_in_sec] AS SELECT ...
+```
+
+**Example:**
+
+```sql
+CREATE LIVE VIEW lv WITH TIMEOUT 15 AND REFRESH 5 AS SELECT now();
+```
+
+After 15 sec the live view will be automatically dropped if there are no active `WATCH` queries.
+
+```sql
+WATCH lv
+```
+
+```
+Code: 60. DB::Exception: Received from localhost:9000. DB::Exception: Table default.lv does not exist..
+```
+
+### Live View Usage {#live-view-usage}
+
+Most common uses of live view tables include:
+
+- Providing push notifications for query result changes to avoid polling.
+- Caching results of most frequent queries to provide immediate query results.
+- Watching for table changes and triggering a follow-up select queries.
+- Watching metrics from system tables using periodic refresh.
+
+**See Also**
+-   [ALTER LIVE VIEW](../alter/view.md#alter-live-view)
+
+## Window View [Experimental] {#window-view}
+
+:::info    
+This is an experimental feature that may change in backwards-incompatible ways in the future releases. Enable usage of window views and `WATCH` query using [allow_experimental_window_view](../../../operations/settings/settings.md#allow-experimental-window-view) setting. Input the command `set allow_experimental_window_view = 1`.
+:::
+
+``` sql
+CREATE WINDOW VIEW [IF NOT EXISTS] [db.]table_name [TO [db.]table_name] [ENGINE = engine] [WATERMARK = strategy] [ALLOWED_LATENESS = interval_function] AS SELECT ... GROUP BY time_window_function
+```
+
+Window view can aggregate data by time window and output the results when the window is ready to fire. It stores the partial aggregation results in an inner(or specified) table to reduce latency and can push the processing result to a specified table or push notifications using the WATCH query.
+
+Creating a window view is similar to creating `MATERIALIZED VIEW`. Window view needs an inner storage engine to store intermediate data. The inner storage will use `AggregatingMergeTree` as the default engine.
+
+### Time Window Functions {#window-view-timewindowfunctions}
+
+[Time window functions](../../functions/time-window-functions.md) are used to get the lower and upper window bound of records. The window view needs to be used with a time window function.
+
+### TIME ATTRIBUTES {#window-view-timeattributes}
+
+Window view supports **processing time** and **event time** process.
+
+**Processing time** allows window view to produce results based on the local machine's time and is used by default. It is the most straightforward notion of time but does not provide determinism. The processing time attribute can be defined by setting the `time_attr` of the time window function to a table column or using the function `now()`. The following query creates a window view with processing time.
+
+``` sql
+CREATE WINDOW VIEW wv AS SELECT count(number), tumbleStart(w_id) as w_start from date GROUP BY tumble(now(), INTERVAL '5' SECOND) as w_id
+```
+
+**Event time** is the time that each individual event occurred on its producing device. This time is typically embedded within the records when it is generated. Event time processing allows for consistent results even in case of out-of-order events or late events. Window view supports event time processing by using `WATERMARK` syntax.
+
+Window view provides three watermark strategies:
+
+* `STRICTLY_ASCENDING`: Emits a watermark of the maximum observed timestamp so far. Rows that have a timestamp smaller to the max timestamp are not late.
+* `ASCENDING`: Emits a watermark of the maximum observed timestamp so far minus 1. Rows that have a timestamp equal and smaller to the max timestamp are not late.
+* `BOUNDED`: WATERMARK=INTERVAL. Emits watermarks, which are the maximum observed timestamp minus the specified delay.
+
+The following queries are examples of creating a window view with `WATERMARK`:
+
+``` sql
+CREATE WINDOW VIEW wv WATERMARK=STRICTLY_ASCENDING AS SELECT count(number) FROM date GROUP BY tumble(timestamp, INTERVAL '5' SECOND);
+CREATE WINDOW VIEW wv WATERMARK=ASCENDING AS SELECT count(number) FROM date GROUP BY tumble(timestamp, INTERVAL '5' SECOND);
+CREATE WINDOW VIEW wv WATERMARK=INTERVAL '3' SECOND AS SELECT count(number) FROM date GROUP BY tumble(timestamp, INTERVAL '5' SECOND);
+```
+
+By default, the window will be fired when the watermark comes, and elements that arrived behind the watermark will be dropped. Window view supports late event processing by setting `ALLOWED_LATENESS=INTERVAL`. An example of lateness handling is:
+
+``` sql
+CREATE WINDOW VIEW test.wv TO test.dst WATERMARK=ASCENDING ALLOWED_LATENESS=INTERVAL '2' SECOND AS SELECT count(a) AS count, tumbleEnd(wid) AS w_end FROM test.mt GROUP BY tumble(timestamp, INTERVAL '5' SECOND) AS wid;
+```
+
+Note that elements emitted by a late firing should be treated as updated results of a previous computation. Instead of firing at the end of windows, the window view will fire immediately when the late event arrives. Thus, it will result in multiple outputs for the same window. Users need to take these duplicated results into account or deduplicate them.
+
+### Monitoring New Windows {#window-view-monitoring}
+
+Window view supports the [WATCH](../../../sql-reference/statements/watch.md) query to monitoring changes, or use `TO` syntax to output the results to a table.
+
+``` sql
+WATCH [db.]window_view
+[EVENTS]
+[LIMIT n]
+[FORMAT format]
+```
+
+`WATCH` query acts similar as in `LIVE VIEW`. A `LIMIT` can be specified to set the number of updates to receive before terminating the query. The `EVENTS` clause can be used to obtain a short form of the `WATCH` query where instead of the query result you will just get the latest query watermark.
+
+### Settings {#window-view-settings}
+
+- `window_view_clean_interval`: The clean interval of window view in seconds to free outdated data. The system will retain the windows that have not been fully triggered according to the system time or `WATERMARK` configuration, and the other data will be deleted.
+- `window_view_heartbeat_interval`: The heartbeat interval in seconds to indicate the watch query is alive.
+
+### Example {#window-view-example}
+
+Suppose we need to count the number of click logs per 10 seconds in a log table called `data`, and its table structure is:
+
+``` sql
+CREATE TABLE data ( `id` UInt64, `timestamp` DateTime) ENGINE = Memory;
+```
+
+First, we create a window view with tumble window of 10 seconds interval:
+
+``` sql
+CREATE WINDOW VIEW wv as select count(id), tumbleStart(w_id) as window_start from data group by tumble(timestamp, INTERVAL '10' SECOND) as w_id
+```
+
+Then, we use the `WATCH` query to get the results.
+
+``` sql
+WATCH wv
+```
+
+When logs are inserted into table `data`,
+
+``` sql
+INSERT INTO data VALUES(1,now())
+```
+
+The `WATCH` query should print the results as follows:
+
+``` text
+┌─count(id)─┬────────window_start─┐
+│         1 │ 2020-01-14 16:56:40 │
+└───────────┴─────────────────────┘
+```
+
+Alternatively, we can attach the output to another table using `TO` syntax.
+
+``` sql
+CREATE WINDOW VIEW wv TO dst AS SELECT count(id), tumbleStart(w_id) as window_start FROM data GROUP BY tumble(timestamp, INTERVAL '10' SECOND) as w_id
+```
+
+Additional examples can be found among stateful tests of ClickHouse (they are named `*window_view*` there).
+
+### Window View Usage {#window-view-usage}
+
+The window view is useful in the following scenarios:
+
+* **Monitoring**: Aggregate and calculate the metrics logs by time, and output the results to a target table. The dashboard can use the target table as a source table.
+* **Analyzing**: Automatically aggregate and preprocess data in the time window. This can be useful when analyzing a large number of logs. The preprocessing eliminates repeated calculations in multiple queries and reduces query latency.
diff --git a/docs/en/reference/sql-reference/statements/describe-table.md b/docs/en/reference/sql-reference/statements/describe-table.md
new file mode 100644
index 00000000000..7fbe5bd2790
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/describe-table.md
@@ -0,0 +1,69 @@
+---
+sidebar_position: 42
+sidebar_label: DESCRIBE
+---
+
+# DESCRIBE TABLE {#misc-describe-table}
+
+Returns information about table columns.
+
+**Syntax**
+
+``` sql
+DESC|DESCRIBE TABLE [db.]table [INTO OUTFILE filename] [FORMAT format]
+```
+
+The `DESCRIBE` statement returns a row for each table column with the following [String](../../sql-reference/data-types/string.md) values:
+
+-   `name` — A column name.
+-   `type` — A column type.
+-   `default_type` — A clause that is used in the column [default expression](../../sql-reference/statements/create/table.md#create-default-values): `DEFAULT`, `MATERIALIZED` or `ALIAS`. If there is no default expression, then empty string is returned.
+-   `default_expression` — An expression specified after the `DEFAULT` clause.
+-   `comment` — A [column comment](../../sql-reference/statements/alter/column.md#alter_comment-column).
+-   `codec_expression` — A [codec](../../sql-reference/statements/create/table.md#codecs) that is applied to the column.
+-   `ttl_expression` — A [TTL](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl) expression.
+-   `is_subcolumn` — A flag that equals `1` for internal subcolumns. It is included into the result only if subcolumn description is enabled by the [describe_include_subcolumns](../../operations/settings/settings.md#describe_include_subcolumns) setting.
+
+All columns in [Nested](../../sql-reference/data-types/nested-data-structures/nested.md) data structures are described separately. The name of each column is prefixed with a parent column name and a dot.
+
+To show internal subcolumns of other data types, use the [describe_include_subcolumns](../../operations/settings/settings.md#describe_include_subcolumns) setting. 
+
+**Example**
+
+Query:
+
+``` sql
+CREATE TABLE describe_example (
+    id UInt64, text String DEFAULT 'unknown' CODEC(ZSTD),
+    user Tuple (name String, age UInt8)
+) ENGINE = MergeTree() ORDER BY id;
+
+DESCRIBE TABLE describe_example;
+DESCRIBE TABLE describe_example SETTINGS describe_include_subcolumns=1;
+```
+
+Result:
+
+``` text
+┌─name─┬─type──────────────────────────┬─default_type─┬─default_expression─┬─comment─┬─codec_expression─┬─ttl_expression─┐
+│ id   │ UInt64                        │              │                    │         │                  │                │
+│ text │ String                        │ DEFAULT      │ 'unknown'          │         │ ZSTD(1)          │                │
+│ user │ Tuple(name String, age UInt8) │              │                    │         │                  │                │
+└──────┴───────────────────────────────┴──────────────┴────────────────────┴─────────┴──────────────────┴────────────────┘
+```
+
+The second query additionally shows subcolumns:
+
+``` text
+┌─name──────┬─type──────────────────────────┬─default_type─┬─default_expression─┬─comment─┬─codec_expression─┬─ttl_expression─┬─is_subcolumn─┐
+│ id        │ UInt64                        │              │                    │         │                  │                │            0 │
+│ text      │ String                        │ DEFAULT      │ 'unknown'          │         │ ZSTD(1)          │                │            0 │
+│ user      │ Tuple(name String, age UInt8) │              │                    │         │                  │                │            0 │
+│ user.name │ String                        │              │                    │         │                  │                │            1 │
+│ user.age  │ UInt8                         │              │                    │         │                  │                │            1 │
+└───────────┴───────────────────────────────┴──────────────┴────────────────────┴─────────┴──────────────────┴────────────────┴──────────────┘
+```
+
+**See Also**
+
+-   [describe_include_subcolumns](../../operations/settings/settings.md#describe_include_subcolumns) setting.
diff --git a/docs/en/reference/sql-reference/statements/detach.md b/docs/en/reference/sql-reference/statements/detach.md
new file mode 100644
index 00000000000..bf20f7b3461
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/detach.md
@@ -0,0 +1,74 @@
+---
+sidebar_position: 43
+sidebar_label: DETACH
+---
+
+# DETACH Statement {#detach}
+
+Makes the server "forget" about the existence of a table, a materialized view, or a dictionary.
+
+**Syntax**
+
+``` sql
+DETACH TABLE|VIEW|DICTIONARY [IF EXISTS] [db.]name [ON CLUSTER cluster] [PERMANENTLY]
+```
+
+Detaching does not delete the data or metadata of a table, a materialized view or a dictionary. If an entity was not detached `PERMANENTLY`, on the next server launch the server will read the metadata and recall the table/view/dictionary again. If an entity was detached `PERMANENTLY`, there will be no automatic recall.
+
+Whether a table or a dictionary was detached permanently or not, in both cases you can reattach them using the [ATTACH](../../sql-reference/statements/attach.md) query.
+System log tables can be also attached back (e.g. `query_log`, `text_log`, etc). Other system tables can't be reattached. On the next server launch the server will recall those tables again.
+
+`ATTACH MATERIALIZED VIEW` does not work with short syntax (without `SELECT`), but you can attach it using the `ATTACH TABLE` query.
+
+Note that you can not detach permanently the table which is already detached (temporary). But you can attach it back and then detach permanently again.
+
+Also you can not [DROP](../../sql-reference/statements/drop.md#drop-table) the detached table, or [CREATE TABLE](../../sql-reference/statements/create/table.md) with the same name as detached permanently, or replace it with the other table with [RENAME TABLE](../../sql-reference/statements/rename.md) query.
+
+**Example**
+
+Creating a table:
+
+Query:
+
+``` sql
+CREATE TABLE test ENGINE = Log AS SELECT * FROM numbers(10);
+SELECT * FROM test;
+```
+
+Result:
+
+``` text
+┌─number─┐
+│      0 │
+│      1 │
+│      2 │
+│      3 │
+│      4 │
+│      5 │
+│      6 │
+│      7 │
+│      8 │
+│      9 │
+└────────┘
+```
+
+Detaching the table:
+
+Query:
+
+``` sql
+DETACH TABLE test;
+SELECT * FROM test;
+```
+
+Result:
+
+``` text
+Received exception from server (version 21.4.1):
+Code: 60. DB::Exception: Received from localhost:9000. DB::Exception: Table default.test does not exist.
+```
+
+**See Also**
+
+-   [Materialized View](../../sql-reference/statements/create/view.md#materialized)
+-   [Dictionaries](../../sql-reference/dictionaries/index.md)
diff --git a/docs/en/reference/sql-reference/statements/drop.md b/docs/en/reference/sql-reference/statements/drop.md
new file mode 100644
index 00000000000..0d3e1f7860d
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/drop.md
@@ -0,0 +1,116 @@
+---
+sidebar_position: 44
+sidebar_label: DROP
+---
+
+# DROP Statements {#drop}
+
+Deletes existing entity. If the `IF EXISTS` clause is specified, these queries do not return an error if the entity does not exist.
+
+## DROP DATABASE {#drop-database}
+
+Deletes all tables inside the `db` database, then deletes the `db` database itself.
+
+Syntax:
+
+``` sql
+DROP DATABASE [IF EXISTS] db [ON CLUSTER cluster]
+```
+
+## DROP TABLE {#drop-table}
+
+Deletes the table.
+
+Syntax:
+
+``` sql
+DROP [TEMPORARY] TABLE [IF EXISTS] [db.]name [ON CLUSTER cluster]
+```
+
+## DROP DICTIONARY {#drop-dictionary}
+
+Deletes the dictionary.
+
+Syntax:
+
+``` sql
+DROP DICTIONARY [IF EXISTS] [db.]name
+```
+
+## DROP USER {#drop-user-statement}
+
+Deletes a user.
+
+Syntax:
+
+``` sql
+DROP USER [IF EXISTS] name [,...] [ON CLUSTER cluster_name]
+```
+
+## DROP ROLE {#drop-role-statement}
+
+Deletes a role. The deleted role is revoked from all the entities where it was assigned.
+
+Syntax:
+
+``` sql
+DROP ROLE [IF EXISTS] name [,...] [ON CLUSTER cluster_name]
+```
+
+## DROP ROW POLICY {#drop-row-policy-statement}
+
+Deletes a row policy. Deleted row policy is revoked from all the entities where it was assigned.
+
+Syntax:
+
+``` sql
+DROP [ROW] POLICY [IF EXISTS] name [,...] ON [database.]table [,...] [ON CLUSTER cluster_name]
+```
+
+## DROP QUOTA {#drop-quota-statement}
+
+Deletes a quota. The deleted quota is revoked from all the entities where it was assigned.
+
+Syntax:
+
+``` sql
+DROP QUOTA [IF EXISTS] name [,...] [ON CLUSTER cluster_name]
+```
+
+## DROP SETTINGS PROFILE {#drop-settings-profile-statement}
+
+Deletes a settings profile. The deleted settings profile is revoked from all the entities where it was assigned.
+
+Syntax:
+
+``` sql
+DROP [SETTINGS] PROFILE [IF EXISTS] name [,...] [ON CLUSTER cluster_name]
+```
+
+## DROP VIEW {#drop-view}
+
+Deletes a view. Views can be deleted by a `DROP TABLE` command as well but `DROP VIEW` checks that `[db.]name` is a view.
+
+Syntax:
+
+``` sql
+DROP VIEW [IF EXISTS] [db.]name [ON CLUSTER cluster]
+```
+
+## DROP FUNCTION {#drop-function}
+
+Deletes a user defined function created by [CREATE FUNCTION](./create/function.md).
+System functions can not be dropped.
+
+**Syntax**
+
+``` sql
+DROP FUNCTION [IF EXISTS] function_name
+```
+
+**Example**
+
+``` sql
+CREATE FUNCTION linear_equation AS (x, k, b) -> k*x + b;
+DROP FUNCTION linear_equation;
+```
diff --git a/docs/en/reference/sql-reference/statements/exchange.md b/docs/en/reference/sql-reference/statements/exchange.md
new file mode 100644
index 00000000000..abe3d40950e
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/exchange.md
@@ -0,0 +1,43 @@
+---
+sidebar_position: 49
+sidebar_label: EXCHANGE
+---
+
+# EXCHANGE Statement {#exchange}
+
+Exchanges the names of two tables or dictionaries atomically.
+This task can also be accomplished with a [RENAME](./rename.md) query using a temporary name, but the operation is not atomic in that case.
+
+:::note    
+The `EXCHANGE` query is supported by the [Atomic](../../engines/database-engines/atomic.md) database engine only.
+:::
+
+**Syntax**
+
+```sql
+EXCHANGE TABLES|DICTIONARIES [db0.]name_A AND [db1.]name_B
+```
+
+## EXCHANGE TABLES {#exchange_tables}
+
+Exchanges the names of two tables.
+
+**Syntax**
+
+```sql
+EXCHANGE TABLES [db0.]table_A AND [db1.]table_B
+```
+
+## EXCHANGE DICTIONARIES {#exchange_dictionaries}
+
+Exchanges the names of two dictionaries.
+
+**Syntax**
+
+```sql
+EXCHANGE DICTIONARIES [db0.]dict_A AND [db1.]dict_B
+```
+
+**See Also**
+
+-   [Dictionaries](../../sql-reference/dictionaries/index.md)
diff --git a/docs/en/reference/sql-reference/statements/exists.md b/docs/en/reference/sql-reference/statements/exists.md
new file mode 100644
index 00000000000..7c6cc812665
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/exists.md
@@ -0,0 +1,12 @@
+---
+sidebar_position: 45
+sidebar_label: EXISTS
+---
+
+# EXISTS Statement {#exists-statement}
+
+``` sql
+EXISTS [TEMPORARY] [TABLE|DICTIONARY] [db.]name [INTO OUTFILE filename] [FORMAT format]
+```
+
+Returns a single `UInt8`-type column, which contains the single value `0` if the table or database does not exist, or `1` if the table exists in the specified database.
diff --git a/docs/en/reference/sql-reference/statements/explain.md b/docs/en/reference/sql-reference/statements/explain.md
new file mode 100644
index 00000000000..80f8961a3e9
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/explain.md
@@ -0,0 +1,454 @@
+---
+sidebar_position: 39
+sidebar_label: EXPLAIN
+---
+
+# EXPLAIN Statement {#explain}
+
+Shows the execution plan of a statement.
+
+Syntax:
+
+```sql
+EXPLAIN [AST | SYNTAX | PLAN | PIPELINE | TABLE OVERRIDE] [setting = value, ...]
+    [
+      SELECT ... |
+      tableFunction(...) [COLUMNS (...)] [ORDER BY ...] [PARTITION BY ...] [PRIMARY KEY] [SAMPLE BY ...] [TTL ...]
+    ]
+    [FORMAT ...]
+```
+
+Example:
+
+```sql
+EXPLAIN SELECT sum(number) FROM numbers(10) UNION ALL SELECT sum(number) FROM numbers(10) ORDER BY sum(number) ASC FORMAT TSV;
+```
+
+```sql
+Union
+  Expression (Projection)
+    Expression (Before ORDER BY and SELECT)
+      Aggregating
+        Expression (Before GROUP BY)
+          SettingQuotaAndLimits (Set limits and quota after reading from storage)
+            ReadFromStorage (SystemNumbers)
+  Expression (Projection)
+    MergingSorted (Merge sorted streams for ORDER BY)
+      MergeSorting (Merge sorted blocks for ORDER BY)
+        PartialSorting (Sort each block for ORDER BY)
+          Expression (Before ORDER BY and SELECT)
+            Aggregating
+              Expression (Before GROUP BY)
+                SettingQuotaAndLimits (Set limits and quota after reading from storage)
+                  ReadFromStorage (SystemNumbers)
+```
+
+## EXPLAIN Types {#explain-types}
+
+-  `AST` — Abstract syntax tree.
+-  `SYNTAX` — Query text after AST-level optimizations.
+-  `PLAN` — Query execution plan.
+-  `PIPELINE` — Query execution pipeline.
+
+### EXPLAIN AST {#explain-ast}
+
+Dump query AST. Supports all types of queries, not only `SELECT`.
+
+Examples:
+
+```sql
+EXPLAIN AST SELECT 1;
+```
+
+```sql
+SelectWithUnionQuery (children 1)
+ ExpressionList (children 1)
+  SelectQuery (children 1)
+   ExpressionList (children 1)
+    Literal UInt64_1
+```
+
+```sql
+EXPLAIN AST ALTER TABLE t1 DELETE WHERE date = today();
+```
+
+```sql
+  explain
+  AlterQuery  t1 (children 1)
+   ExpressionList (children 1)
+    AlterCommand 27 (children 1)
+     Function equals (children 1)
+      ExpressionList (children 2)
+       Identifier date
+       Function today (children 1)
+        ExpressionList
+```
+
+### EXPLAIN SYNTAX {#explain-syntax}
+
+Returns query after syntax optimizations.
+
+Example:
+
+```sql
+EXPLAIN SYNTAX SELECT * FROM system.numbers AS a, system.numbers AS b, system.numbers AS c;
+```
+
+```sql
+SELECT
+    `--a.number` AS `a.number`,
+    `--b.number` AS `b.number`,
+    number AS `c.number`
+FROM
+(
+    SELECT
+        number AS `--a.number`,
+        b.number AS `--b.number`
+    FROM system.numbers AS a
+    CROSS JOIN system.numbers AS b
+) AS `--.s`
+CROSS JOIN system.numbers AS c
+```
+
+### EXPLAIN PLAN {#explain-plan}
+
+Dump query plan steps.
+
+Settings:
+
+-   `header` — Prints output header for step. Default: 0.
+-   `description` — Prints step description. Default: 1.
+-   `indexes` — Shows used indexes, the number of filtered parts and the number of filtered granules for every index applied. Default: 0. Supported for [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables.
+-   `actions` — Prints detailed information about step actions. Default: 0.
+-   `json` — Prints query plan steps as a row in [JSON](../../interfaces/formats.md#json) format. Default: 0. It is recommended to use [TSVRaw](../../interfaces/formats.md#tabseparatedraw) format to avoid unnecessary escaping.
+
+Example:
+
+```sql
+EXPLAIN SELECT sum(number) FROM numbers(10) GROUP BY number % 4;
+```
+
+```sql
+Union
+  Expression (Projection)
+  Expression (Before ORDER BY and SELECT)
+    Aggregating
+      Expression (Before GROUP BY)
+        SettingQuotaAndLimits (Set limits and quota after reading from storage)
+          ReadFromStorage (SystemNumbers)
+```
+
+:::note    
+Step and query cost estimation is not supported.
+:::
+
+When `json = 1`, the query plan is represented in JSON format. Every node is a dictionary that always has the keys `Node Type` and `Plans`. `Node Type` is a string with a step name. `Plans` is an array with child step descriptions. Other optional keys may be added depending on node type and settings.
+
+Example:
+
+```sql
+EXPLAIN json = 1, description = 0 SELECT 1 UNION ALL SELECT 2 FORMAT TSVRaw;
+```
+
+```json
+[
+  {
+    "Plan": {
+      "Node Type": "Union",
+      "Plans": [
+        {
+          "Node Type": "Expression",
+          "Plans": [
+            {
+              "Node Type": "SettingQuotaAndLimits",
+              "Plans": [
+                {
+                  "Node Type": "ReadFromStorage"
+                }
+              ]
+            }
+          ]
+        },
+        {
+          "Node Type": "Expression",
+          "Plans": [
+            {
+              "Node Type": "SettingQuotaAndLimits",
+              "Plans": [
+                {
+                  "Node Type": "ReadFromStorage"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    }
+  }
+]
+```
+
+With `description` = 1, the `Description` key is added to the step:
+
+```json
+{
+  "Node Type": "ReadFromStorage",
+  "Description": "SystemOne"
+}
+```
+
+With `header` = 1, the `Header` key is added to the step as an array of columns.
+
+Example:
+
+```sql
+EXPLAIN json = 1, description = 0, header = 1 SELECT 1, 2 + dummy;
+```
+
+```json
+[
+  {
+    "Plan": {
+      "Node Type": "Expression",
+      "Header": [
+        {
+          "Name": "1",
+          "Type": "UInt8"
+        },
+        {
+          "Name": "plus(2, dummy)",
+          "Type": "UInt16"
+        }
+      ],
+      "Plans": [
+        {
+          "Node Type": "SettingQuotaAndLimits",
+          "Header": [
+            {
+              "Name": "dummy",
+              "Type": "UInt8"
+            }
+          ],
+          "Plans": [
+            {
+              "Node Type": "ReadFromStorage",
+              "Header": [
+                {
+                  "Name": "dummy",
+                  "Type": "UInt8"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    }
+  }
+]
+```
+
+With `indexes` = 1, the `Indexes` key is added. It contains an array of used indexes. Each index is described as JSON with `Type` key (a string `MinMax`, `Partition`, `PrimaryKey` or `Skip`) and optional keys:
+
+-   `Name` — An index name (for now, is used only for `Skip` index).
+-   `Keys` — An array of columns used by the index.
+-   `Condition` — A string with condition used.
+-   `Description` — An index (for now, is used only for `Skip` index).
+-   `Initial Parts` — A number of parts before the index is applied.
+-   `Selected Parts` — A number of parts after the index is applied.
+-   `Initial Granules` — A number of granules before the index is applied.
+-   `Selected Granulesis` — A number of granules after the index is applied.
+
+Example:
+
+```json
+"Node Type": "ReadFromMergeTree",
+"Indexes": [
+  {
+    "Type": "MinMax",
+    "Keys": ["y"],
+    "Condition": "(y in [1, +inf))",
+    "Initial Parts": 5,
+    "Selected Parts": 4,
+    "Initial Granules": 12,
+    "Selected Granules": 11
+  },
+  {
+    "Type": "Partition",
+    "Keys": ["y", "bitAnd(z, 3)"],
+    "Condition": "and((bitAnd(z, 3) not in [1, 1]), and((y in [1, +inf)), (bitAnd(z, 3) not in [1, 1])))",
+    "Initial Parts": 4,
+    "Selected Parts": 3,
+    "Initial Granules": 11,
+    "Selected Granules": 10
+  },
+  {
+    "Type": "PrimaryKey",
+    "Keys": ["x", "y"],
+    "Condition": "and((x in [11, +inf)), (y in [1, +inf)))",
+    "Initial Parts": 3,
+    "Selected Parts": 2,
+    "Initial Granules": 10,
+    "Selected Granules": 6
+  },
+  {
+    "Type": "Skip",
+    "Name": "t_minmax",
+    "Description": "minmax GRANULARITY 2",
+    "Initial Parts": 2,
+    "Selected Parts": 1,
+    "Initial Granules": 6,
+    "Selected Granules": 2
+  },
+  {
+    "Type": "Skip",
+    "Name": "t_set",
+    "Description": "set GRANULARITY 2",
+    "Initial Parts": 1,
+    "Selected Parts": 1,
+    "Initial Granules": 2,
+    "Selected Granules": 1
+  }
+]
+```
+
+With `actions` = 1, added keys depend on step type.
+
+Example:
+
+```sql
+EXPLAIN json = 1, actions = 1, description = 0 SELECT 1 FORMAT TSVRaw;
+```
+
+```json
+[
+  {
+    "Plan": {
+      "Node Type": "Expression",
+      "Expression": {
+        "Inputs": [],
+        "Actions": [
+          {
+            "Node Type": "Column",
+            "Result Type": "UInt8",
+            "Result Type": "Column",
+            "Column": "Const(UInt8)",
+            "Arguments": [],
+            "Removed Arguments": [],
+            "Result": 0
+          }
+        ],
+        "Outputs": [
+          {
+            "Name": "1",
+            "Type": "UInt8"
+          }
+        ],
+        "Positions": [0],
+        "Project Input": true
+      },
+      "Plans": [
+        {
+          "Node Type": "SettingQuotaAndLimits",
+          "Plans": [
+            {
+              "Node Type": "ReadFromStorage"
+            }
+          ]
+        }
+      ]
+    }
+  }
+]
+```
+
+### EXPLAIN PIPELINE {#explain-pipeline}
+
+Settings:
+
+-   `header` — Prints header for each output port. Default: 0.
+-   `graph` — Prints a graph described in the [DOT](https://en.wikipedia.org/wiki/DOT_(graph_description_language)) graph description language. Default: 0.
+-   `compact` — Prints graph in compact mode if `graph` setting is enabled. Default: 1.
+
+Example:
+
+```sql
+EXPLAIN PIPELINE SELECT sum(number) FROM numbers_mt(100000) GROUP BY number % 4;
+```
+
+```sql
+(Union)
+(Expression)
+ExpressionTransform
+  (Expression)
+  ExpressionTransform
+    (Aggregating)
+    Resize 2 → 1
+      AggregatingTransform × 2
+        (Expression)
+        ExpressionTransform × 2
+          (SettingQuotaAndLimits)
+            (ReadFromStorage)
+            NumbersMt × 2 0 → 1
+```
+### EXPLAIN ESTIMATE {#explain-estimate}
+
+Shows the estimated number of rows, marks and parts to be read from the tables while processing the query. Works with tables in the [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md#table_engines-mergetree) family. 
+
+**Example**
+
+Creating a table:
+
+```sql
+CREATE TABLE ttt (i Int64) ENGINE = MergeTree() ORDER BY i SETTINGS index_granularity = 16, write_final_mark = 0;
+INSERT INTO ttt SELECT number FROM numbers(128);
+OPTIMIZE TABLE ttt;
+```
+
+Query:
+
+```sql
+EXPLAIN ESTIMATE SELECT * FROM ttt;
+```
+
+Result:
+
+```text
+┌─database─┬─table─┬─parts─┬─rows─┬─marks─┐
+│ default  │ ttt   │     1 │  128 │     8 │
+└──────────┴───────┴───────┴──────┴───────┘
+```
+
+### EXPLAIN TABLE OVERRIDE {#explain-table-override}
+
+Shows the result of a table override on a table schema accessed through a table function.
+Also does some validation, throwing an exception if the override would have caused some kind of failure.
+
+**Example**
+
+Assume you have a remote MySQL table like this:
+
+```sql
+CREATE TABLE db.tbl (
+    id INT PRIMARY KEY,
+    created DATETIME DEFAULT now()
+)
+```
+
+```sql
+EXPLAIN TABLE OVERRIDE mysql('127.0.0.1:3306', 'db', 'tbl', 'root', 'clickhouse')
+PARTITION BY toYYYYMM(assumeNotNull(created))
+```
+
+Result:
+
+```text
+┌─explain─────────────────────────────────────────────────┐
+│ PARTITION BY uses columns: `created` Nullable(DateTime) │
+└─────────────────────────────────────────────────────────┘
+```
+
+:::note    
+The validation is not complete, so a successfull query does not guarantee that the override would not cause issues.
+:::
+
+[Оriginal article](https://clickhouse.com/docs/en/sql-reference/statements/explain/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/statements/grant.md b/docs/en/reference/sql-reference/statements/grant.md
new file mode 100644
index 00000000000..1ee330061b5
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/grant.md
@@ -0,0 +1,483 @@
+---
+sidebar_position: 38
+sidebar_label: GRANT
+---
+
+# GRANT Statement {#grant}
+
+-   Grants [privileges](#grant-privileges) to ClickHouse user accounts or roles.
+-   Assigns roles to user accounts or to the other roles.
+
+To revoke privileges, use the [REVOKE](../../sql-reference/statements/revoke.md) statement. Also you can list granted privileges with the [SHOW GRANTS](../../sql-reference/statements/show.md#show-grants-statement) statement.
+
+## Granting Privilege Syntax {#grant-privigele-syntax}
+
+``` sql
+GRANT [ON CLUSTER cluster_name] privilege[(column_name [,...])] [,...] ON {db.table|db.*|*.*|table|*} TO {user | role | CURRENT_USER} [,...] [WITH GRANT OPTION] [WITH REPLACE OPTION]
+```
+
+-   `privilege` — Type of privilege.
+-   `role` — ClickHouse user role.
+-   `user` — ClickHouse user account.
+
+The `WITH GRANT OPTION` clause grants `user` or `role` with permission to execute the `GRANT` query. Users can grant privileges of the same scope they have and less.
+The `WITH REPLACE OPTION` clause replace old privileges by new privileges for the `user` or `role`, if is not specified it appends privileges.
+
+## Assigning Role Syntax {#assign-role-syntax}
+
+``` sql
+GRANT [ON CLUSTER cluster_name] role [,...] TO {user | another_role | CURRENT_USER} [,...] [WITH ADMIN OPTION] [WITH REPLACE OPTION]
+```
+
+-   `role` — ClickHouse user role.
+-   `user` — ClickHouse user account.
+
+The `WITH ADMIN OPTION` clause grants [ADMIN OPTION](#admin-option-privilege) privilege to `user` or `role`.
+The `WITH REPLACE OPTION` clause replace old roles by new role for the `user` or `role`, if is not specified it appends roles.
+
+## Usage {#grant-usage}
+
+To use `GRANT`, your account must have the `GRANT OPTION` privilege. You can grant privileges only inside the scope of your account privileges.
+
+For example, administrator has granted privileges to the `john` account by the query:
+
+``` sql
+GRANT SELECT(x,y) ON db.table TO john WITH GRANT OPTION
+```
+
+It means that `john` has the permission to execute:
+
+-   `SELECT x,y FROM db.table`.
+-   `SELECT x FROM db.table`.
+-   `SELECT y FROM db.table`.
+
+`john` can’t execute `SELECT z FROM db.table`. The `SELECT * FROM db.table` also is not available. Processing this query, ClickHouse does not return any data, even `x` and `y`. The only exception is if a table contains only `x` and `y` columns. In this case ClickHouse returns all the data.
+
+Also `john` has the `GRANT OPTION` privilege, so it can grant other users with privileges of the same or smaller scope.
+
+Specifying privileges you can use asterisk (`*`) instead of a table or a database name. For example, the `GRANT SELECT ON db.* TO john` query allows `john` to execute the `SELECT` query over all the tables in `db` database. Also, you can omit database name. In this case privileges are granted for current database. For example, `GRANT SELECT ON * TO john` grants the privilege on all the tables in the current database, `GRANT SELECT ON mytable TO john` grants the privilege on the `mytable` table in the current database.
+
+Access to the `system` database is always allowed (since this database is used for processing queries).
+
+You can grant multiple privileges to multiple accounts in one query. The query `GRANT SELECT, INSERT ON *.* TO john, robin` allows accounts `john` and `robin` to execute the `INSERT` and `SELECT` queries over all the tables in all the databases on the server.
+
+## Privileges {#grant-privileges}
+
+Privilege is a permission to execute specific kind of queries.
+
+Privileges have a hierarchical structure. A set of permitted queries depends on the privilege scope.
+
+Hierarchy of privileges:
+
+-   [SELECT](#grant-select)
+-   [INSERT](#grant-insert)
+-   [ALTER](#grant-alter)
+    -   `ALTER TABLE`
+        -   `ALTER UPDATE`
+        -   `ALTER DELETE`
+        -   `ALTER COLUMN`
+            -   `ALTER ADD COLUMN`
+            -   `ALTER DROP COLUMN`
+            -   `ALTER MODIFY COLUMN`
+            -   `ALTER COMMENT COLUMN`
+            -   `ALTER CLEAR COLUMN`
+            -   `ALTER RENAME COLUMN`
+        -   `ALTER INDEX`
+            -   `ALTER ORDER BY`
+            -   `ALTER SAMPLE BY`
+            -   `ALTER ADD INDEX`
+            -   `ALTER DROP INDEX`
+            -   `ALTER MATERIALIZE INDEX`
+            -   `ALTER CLEAR INDEX`
+        -   `ALTER CONSTRAINT`
+            -   `ALTER ADD CONSTRAINT`
+            -   `ALTER DROP CONSTRAINT`
+        -   `ALTER TTL`
+            -   `ALTER MATERIALIZE TTL`
+        -   `ALTER SETTINGS`
+        -   `ALTER MOVE PARTITION`
+        -   `ALTER FETCH PARTITION`
+        -   `ALTER FREEZE PARTITION`
+    -   `ALTER VIEW`
+        -   `ALTER VIEW REFRESH`
+        -   `ALTER VIEW MODIFY QUERY`
+-   [CREATE](#grant-create)
+    -   `CREATE DATABASE`
+    -   `CREATE TABLE`
+        -   `CREATE TEMPORARY TABLE`
+    -   `CREATE VIEW`
+    -   `CREATE DICTIONARY`
+    -   `CREATE FUNCTION`
+-   [DROP](#grant-drop)
+    -   `DROP DATABASE`
+    -   `DROP TABLE`
+    -   `DROP VIEW`
+    -   `DROP DICTIONARY`
+    -   `DROP FUNCTION`
+-   [TRUNCATE](#grant-truncate)
+-   [OPTIMIZE](#grant-optimize)
+-   [SHOW](#grant-show)
+    -   `SHOW DATABASES`
+    -   `SHOW TABLES`
+    -   `SHOW COLUMNS`
+    -   `SHOW DICTIONARIES`
+-   [KILL QUERY](#grant-kill-query)
+-   [ACCESS MANAGEMENT](#grant-access-management)
+    -   `CREATE USER`
+    -   `ALTER USER`
+    -   `DROP USER`
+    -   `CREATE ROLE`
+    -   `ALTER ROLE`
+    -   `DROP ROLE`
+    -   `CREATE ROW POLICY`
+    -   `ALTER ROW POLICY`
+    -   `DROP ROW POLICY`
+    -   `CREATE QUOTA`
+    -   `ALTER QUOTA`
+    -   `DROP QUOTA`
+    -   `CREATE SETTINGS PROFILE`
+    -   `ALTER SETTINGS PROFILE`
+    -   `DROP SETTINGS PROFILE`
+    -   `SHOW ACCESS`
+        -   `SHOW_USERS`
+        -   `SHOW_ROLES`
+        -   `SHOW_ROW_POLICIES`
+        -   `SHOW_QUOTAS`
+        -   `SHOW_SETTINGS_PROFILES`
+    -   `ROLE ADMIN`
+-   [SYSTEM](#grant-system)
+    -   `SYSTEM SHUTDOWN`
+    -   `SYSTEM DROP CACHE`
+        -   `SYSTEM DROP DNS CACHE`
+        -   `SYSTEM DROP MARK CACHE`
+        -   `SYSTEM DROP UNCOMPRESSED CACHE`
+    -   `SYSTEM RELOAD`
+        -   `SYSTEM RELOAD CONFIG`
+        -   `SYSTEM RELOAD DICTIONARY`
+            -   `SYSTEM RELOAD EMBEDDED DICTIONARIES`
+        -   `SYSTEM RELOAD FUNCTION`
+        -   `SYSTEM RELOAD FUNCTIONS`
+    -   `SYSTEM MERGES`
+    -   `SYSTEM TTL MERGES`
+    -   `SYSTEM FETCHES`
+    -   `SYSTEM MOVES`
+    -   `SYSTEM SENDS`
+        -   `SYSTEM DISTRIBUTED SENDS`
+        -   `SYSTEM REPLICATED SENDS`
+    -   `SYSTEM REPLICATION QUEUES`
+    -   `SYSTEM SYNC REPLICA`
+    -   `SYSTEM RESTART REPLICA`
+    -   `SYSTEM FLUSH`
+        -   `SYSTEM FLUSH DISTRIBUTED`
+        -   `SYSTEM FLUSH LOGS`
+-   [INTROSPECTION](#grant-introspection)
+    -   `addressToLine`
+    -   `addressToLineWithInlines`
+    -   `addressToSymbol`
+    -   `demangle`
+-   [SOURCES](#grant-sources)
+    -   `FILE`
+    -   `URL`
+    -   `REMOTE`
+    -   `YSQL`
+    -   `ODBC`
+    -   `JDBC`
+    -   `HDFS`
+    -   `S3`
+-   [dictGet](#grant-dictget)
+
+Examples of how this hierarchy is treated:
+
+-   The `ALTER` privilege includes all other `ALTER*` privileges.
+-   `ALTER CONSTRAINT` includes `ALTER ADD CONSTRAINT` and `ALTER DROP CONSTRAINT` privileges.
+
+Privileges are applied at different levels. Knowing of a level suggests syntax available for privilege.
+
+Levels (from lower to higher):
+
+-   `COLUMN` — Privilege can be granted for column, table, database, or globally.
+-   `TABLE` — Privilege can be granted for table, database, or globally.
+-   `VIEW` — Privilege can be granted for view, database, or globally.
+-   `DICTIONARY` — Privilege can be granted for dictionary, database, or globally.
+-   `DATABASE` — Privilege can be granted for database or globally.
+-   `GLOBAL` — Privilege can be granted only globally.
+-   `GROUP` — Groups privileges of different levels. When `GROUP`-level privilege is granted, only that privileges from the group are granted which correspond to the used syntax.
+
+Examples of allowed syntax:
+
+-   `GRANT SELECT(x) ON db.table TO user`
+-   `GRANT SELECT ON db.* TO user`
+
+Examples of disallowed syntax:
+
+-   `GRANT CREATE USER(x) ON db.table TO user`
+-   `GRANT CREATE USER ON db.* TO user`
+
+The special privilege [ALL](#grant-all) grants all the privileges to a user account or a role.
+
+By default, a user account or a role has no privileges.
+
+If a user or a role has no privileges, it is displayed as [NONE](#grant-none) privilege.
+
+Some queries by their implementation require a set of privileges. For example, to execute the [RENAME](../../sql-reference/statements/misc.md#misc_operations-rename) query you need the following privileges: `SELECT`, `CREATE TABLE`, `INSERT` and `DROP TABLE`.
+
+### SELECT {#grant-select}
+
+Allows executing [SELECT](../../sql-reference/statements/select/index.md) queries.
+
+Privilege level: `COLUMN`.
+
+**Description**
+
+User granted with this privilege can execute `SELECT` queries over a specified list of columns in the specified table and database. If user includes other columns then specified a query returns no data.
+
+Consider the following privilege:
+
+``` sql
+GRANT SELECT(x,y) ON db.table TO john
+```
+
+This privilege allows `john` to execute any `SELECT` query that involves data from the `x` and/or `y` columns in `db.table`, for example, `SELECT x FROM db.table`. `john` can’t execute `SELECT z FROM db.table`. The `SELECT * FROM db.table` also is not available. Processing this query, ClickHouse does not return any data, even `x` and `y`. The only exception is if a table contains only `x` and `y` columns, in this case ClickHouse returns all the data.
+
+### INSERT {#grant-insert}
+
+Allows executing [INSERT](../../sql-reference/statements/insert-into.md) queries.
+
+Privilege level: `COLUMN`.
+
+**Description**
+
+User granted with this privilege can execute `INSERT` queries over a specified list of columns in the specified table and database. If user includes other columns then specified a query does not insert any data.
+
+**Example**
+
+``` sql
+GRANT INSERT(x,y) ON db.table TO john
+```
+
+The granted privilege allows `john` to insert data to the `x` and/or `y` columns in `db.table`.
+
+### ALTER {#grant-alter}
+
+Allows executing [ALTER](../../sql-reference/statements/alter/index.md) queries according to the following hierarchy of privileges:
+
+-   `ALTER`. Level: `COLUMN`.
+    -   `ALTER TABLE`. Level: `GROUP`
+        -   `ALTER UPDATE`. Level: `COLUMN`. Aliases: `UPDATE`
+        -   `ALTER DELETE`. Level: `COLUMN`. Aliases: `DELETE`
+        -   `ALTER COLUMN`. Level: `GROUP`
+            -   `ALTER ADD COLUMN`. Level: `COLUMN`. Aliases: `ADD COLUMN`
+            -   `ALTER DROP COLUMN`. Level: `COLUMN`. Aliases: `DROP COLUMN`
+            -   `ALTER MODIFY COLUMN`. Level: `COLUMN`. Aliases: `MODIFY COLUMN`
+            -   `ALTER COMMENT COLUMN`. Level: `COLUMN`. Aliases: `COMMENT COLUMN`
+            -   `ALTER CLEAR COLUMN`. Level: `COLUMN`. Aliases: `CLEAR COLUMN`
+            -   `ALTER RENAME COLUMN`. Level: `COLUMN`. Aliases: `RENAME COLUMN`
+        -   `ALTER INDEX`. Level: `GROUP`. Aliases: `INDEX`
+            -   `ALTER ORDER BY`. Level: `TABLE`. Aliases: `ALTER MODIFY ORDER BY`, `MODIFY ORDER BY`
+            -   `ALTER SAMPLE BY`. Level: `TABLE`. Aliases: `ALTER MODIFY SAMPLE BY`, `MODIFY SAMPLE BY`
+            -   `ALTER ADD INDEX`. Level: `TABLE`. Aliases: `ADD INDEX`
+            -   `ALTER DROP INDEX`. Level: `TABLE`. Aliases: `DROP INDEX`
+            -   `ALTER MATERIALIZE INDEX`. Level: `TABLE`. Aliases: `MATERIALIZE INDEX`
+            -   `ALTER CLEAR INDEX`. Level: `TABLE`. Aliases: `CLEAR INDEX`
+        -   `ALTER CONSTRAINT`. Level: `GROUP`. Aliases: `CONSTRAINT`
+            -   `ALTER ADD CONSTRAINT`. Level: `TABLE`. Aliases: `ADD CONSTRAINT`
+            -   `ALTER DROP CONSTRAINT`. Level: `TABLE`. Aliases: `DROP CONSTRAINT`
+        -   `ALTER TTL`. Level: `TABLE`. Aliases: `ALTER MODIFY TTL`, `MODIFY TTL`
+            -   `ALTER MATERIALIZE TTL`. Level: `TABLE`. Aliases: `MATERIALIZE TTL`
+        -   `ALTER SETTINGS`. Level: `TABLE`. Aliases: `ALTER SETTING`, `ALTER MODIFY SETTING`, `MODIFY SETTING`
+        -   `ALTER MOVE PARTITION`. Level: `TABLE`. Aliases: `ALTER MOVE PART`, `MOVE PARTITION`, `MOVE PART`
+        -   `ALTER FETCH PARTITION`. Level: `TABLE`. Aliases: `ALTER FETCH PART`, `FETCH PARTITION`, `FETCH PART`
+        -   `ALTER FREEZE PARTITION`. Level: `TABLE`. Aliases: `FREEZE PARTITION`
+    -   `ALTER VIEW` Level: `GROUP`
+        -   `ALTER VIEW REFRESH`. Level: `VIEW`. Aliases: `ALTER LIVE VIEW REFRESH`, `REFRESH VIEW`
+        -   `ALTER VIEW MODIFY QUERY`. Level: `VIEW`. Aliases: `ALTER TABLE MODIFY QUERY`
+
+Examples of how this hierarchy is treated:
+
+-   The `ALTER` privilege includes all other `ALTER*` privileges.
+-   `ALTER CONSTRAINT` includes `ALTER ADD CONSTRAINT` and `ALTER DROP CONSTRAINT` privileges.
+
+**Notes**
+
+-   The `MODIFY SETTING` privilege allows modifying table engine settings. It does not affect settings or server configuration parameters.
+-   The `ATTACH` operation needs the [CREATE](#grant-create) privilege.
+-   The `DETACH` operation needs the [DROP](#grant-drop) privilege.
+-   To stop mutation by the [KILL MUTATION](../../sql-reference/statements/misc.md#kill-mutation) query, you need to have a privilege to start this mutation. For example, if you want to stop the `ALTER UPDATE` query, you need the `ALTER UPDATE`, `ALTER TABLE`, or `ALTER` privilege.
+
+### CREATE {#grant-create}
+
+Allows executing [CREATE](../../sql-reference/statements/create/index.md) and [ATTACH](../../sql-reference/statements/misc.md#attach) DDL-queries according to the following hierarchy of privileges:
+
+-   `CREATE`. Level: `GROUP`
+    -   `CREATE DATABASE`. Level: `DATABASE`
+    -   `CREATE TABLE`. Level: `TABLE`
+        -   `CREATE TEMPORARY TABLE`. Level: `GLOBAL`
+    -   `CREATE VIEW`. Level: `VIEW`
+    -   `CREATE DICTIONARY`. Level: `DICTIONARY`
+
+**Notes**
+
+-   To delete the created table, a user needs [DROP](#grant-drop).
+
+### DROP {#grant-drop}
+
+Allows executing [DROP](../../sql-reference/statements/misc.md#drop) and [DETACH](../../sql-reference/statements/misc.md#detach) queries according to the following hierarchy of privileges:
+
+-   `DROP`. Level: `GROUP`
+    -   `DROP DATABASE`. Level: `DATABASE`
+    -   `DROP TABLE`. Level: `TABLE`
+    -   `DROP VIEW`. Level: `VIEW`
+    -   `DROP DICTIONARY`. Level: `DICTIONARY`
+
+### TRUNCATE {#grant-truncate}
+
+Allows executing [TRUNCATE](../../sql-reference/statements/misc.md#truncate-statement) queries.
+
+Privilege level: `TABLE`.
+
+### OPTIMIZE {#grant-optimize}
+
+Allows executing [OPTIMIZE TABLE](../../sql-reference/statements/misc.md#misc_operations-optimize) queries.
+
+Privilege level: `TABLE`.
+
+### SHOW {#grant-show}
+
+Allows executing `SHOW`, `DESCRIBE`, `USE`, and `EXISTS` queries according to the following hierarchy of privileges:
+
+-   `SHOW`. Level: `GROUP`
+    -   `SHOW DATABASES`. Level: `DATABASE`. Allows to execute `SHOW DATABASES`, `SHOW CREATE DATABASE`, `USE <database>` queries.
+    -   `SHOW TABLES`. Level: `TABLE`. Allows to execute `SHOW TABLES`, `EXISTS <table>`, `CHECK <table>` queries.
+    -   `SHOW COLUMNS`. Level: `COLUMN`. Allows to execute `SHOW CREATE TABLE`, `DESCRIBE` queries.
+    -   `SHOW DICTIONARIES`. Level: `DICTIONARY`. Allows to execute `SHOW DICTIONARIES`, `SHOW CREATE DICTIONARY`, `EXISTS <dictionary>` queries.
+
+**Notes**
+
+A user has the `SHOW` privilege if it has any other privilege concerning the specified table, dictionary or database.
+
+### KILL QUERY {#grant-kill-query}
+
+Allows executing [KILL](../../sql-reference/statements/misc.md#kill-query-statement) queries according to the following hierarchy of privileges:
+
+Privilege level: `GLOBAL`.
+
+**Notes**
+
+`KILL QUERY` privilege allows one user to kill queries of other users.
+
+### ACCESS MANAGEMENT {#grant-access-management}
+
+Allows a user to execute queries that manage users, roles and row policies.
+
+-   `ACCESS MANAGEMENT`. Level: `GROUP`
+    -   `CREATE USER`. Level: `GLOBAL`
+    -   `ALTER USER`. Level: `GLOBAL`
+    -   `DROP USER`. Level: `GLOBAL`
+    -   `CREATE ROLE`. Level: `GLOBAL`
+    -   `ALTER ROLE`. Level: `GLOBAL`
+    -   `DROP ROLE`. Level: `GLOBAL`
+    -   `ROLE ADMIN`. Level: `GLOBAL`
+    -   `CREATE ROW POLICY`. Level: `GLOBAL`. Aliases: `CREATE POLICY`
+    -   `ALTER ROW POLICY`. Level: `GLOBAL`. Aliases: `ALTER POLICY`
+    -   `DROP ROW POLICY`. Level: `GLOBAL`. Aliases: `DROP POLICY`
+    -   `CREATE QUOTA`. Level: `GLOBAL`
+    -   `ALTER QUOTA`. Level: `GLOBAL`
+    -   `DROP QUOTA`. Level: `GLOBAL`
+    -   `CREATE SETTINGS PROFILE`. Level: `GLOBAL`. Aliases: `CREATE PROFILE`
+    -   `ALTER SETTINGS PROFILE`. Level: `GLOBAL`. Aliases: `ALTER PROFILE`
+    -   `DROP SETTINGS PROFILE`. Level: `GLOBAL`. Aliases: `DROP PROFILE`
+    -   `SHOW ACCESS`. Level: `GROUP`
+        -   `SHOW_USERS`. Level: `GLOBAL`. Aliases: `SHOW CREATE USER`
+        -   `SHOW_ROLES`. Level: `GLOBAL`. Aliases: `SHOW CREATE ROLE`
+        -   `SHOW_ROW_POLICIES`. Level: `GLOBAL`. Aliases: `SHOW POLICIES`, `SHOW CREATE ROW POLICY`, `SHOW CREATE POLICY`
+        -   `SHOW_QUOTAS`. Level: `GLOBAL`. Aliases: `SHOW CREATE QUOTA`
+        -   `SHOW_SETTINGS_PROFILES`. Level: `GLOBAL`. Aliases: `SHOW PROFILES`, `SHOW CREATE SETTINGS PROFILE`, `SHOW CREATE PROFILE`
+
+The `ROLE ADMIN` privilege allows a user to assign and revoke any roles including those which are not assigned to the user with the admin option.
+
+### SYSTEM {#grant-system}
+
+Allows a user to execute [SYSTEM](../../sql-reference/statements/system.md) queries according to the following hierarchy of privileges.
+
+-   `SYSTEM`. Level: `GROUP`
+    -   `SYSTEM SHUTDOWN`. Level: `GLOBAL`. Aliases: `SYSTEM KILL`, `SHUTDOWN`
+    -   `SYSTEM DROP CACHE`. Aliases: `DROP CACHE`
+        -   `SYSTEM DROP DNS CACHE`. Level: `GLOBAL`. Aliases: `SYSTEM DROP DNS`, `DROP DNS CACHE`, `DROP DNS`
+        -   `SYSTEM DROP MARK CACHE`. Level: `GLOBAL`. Aliases: `SYSTEM DROP MARK`, `DROP MARK CACHE`, `DROP MARKS`
+        -   `SYSTEM DROP UNCOMPRESSED CACHE`. Level: `GLOBAL`. Aliases: `SYSTEM DROP UNCOMPRESSED`, `DROP UNCOMPRESSED CACHE`, `DROP UNCOMPRESSED`
+    -   `SYSTEM RELOAD`. Level: `GROUP`
+        -   `SYSTEM RELOAD CONFIG`. Level: `GLOBAL`. Aliases: `RELOAD CONFIG`
+        -   `SYSTEM RELOAD DICTIONARY`. Level: `GLOBAL`. Aliases: `SYSTEM RELOAD DICTIONARIES`, `RELOAD DICTIONARY`, `RELOAD DICTIONARIES`
+            -   `SYSTEM RELOAD EMBEDDED DICTIONARIES`. Level: `GLOBAL`. Aliases: `RELOAD EMBEDDED DICTIONARIES`
+    -   `SYSTEM MERGES`. Level: `TABLE`. Aliases: `SYSTEM STOP MERGES`, `SYSTEM START MERGES`, `STOP MERGES`, `START MERGES`
+    -   `SYSTEM TTL MERGES`. Level: `TABLE`. Aliases: `SYSTEM STOP TTL MERGES`, `SYSTEM START TTL MERGES`, `STOP TTL MERGES`, `START TTL MERGES`
+    -   `SYSTEM FETCHES`. Level: `TABLE`. Aliases: `SYSTEM STOP FETCHES`, `SYSTEM START FETCHES`, `STOP FETCHES`, `START FETCHES`
+    -   `SYSTEM MOVES`. Level: `TABLE`. Aliases: `SYSTEM STOP MOVES`, `SYSTEM START MOVES`, `STOP MOVES`, `START MOVES`
+    -   `SYSTEM SENDS`. Level: `GROUP`. Aliases: `SYSTEM STOP SENDS`, `SYSTEM START SENDS`, `STOP SENDS`, `START SENDS`
+        -   `SYSTEM DISTRIBUTED SENDS`. Level: `TABLE`. Aliases: `SYSTEM STOP DISTRIBUTED SENDS`, `SYSTEM START DISTRIBUTED SENDS`, `STOP DISTRIBUTED SENDS`, `START DISTRIBUTED SENDS`
+        -   `SYSTEM REPLICATED SENDS`. Level: `TABLE`. Aliases: `SYSTEM STOP REPLICATED SENDS`, `SYSTEM START REPLICATED SENDS`, `STOP REPLICATED SENDS`, `START REPLICATED SENDS`
+    -   `SYSTEM REPLICATION QUEUES`. Level: `TABLE`. Aliases: `SYSTEM STOP REPLICATION QUEUES`, `SYSTEM START REPLICATION QUEUES`, `STOP REPLICATION QUEUES`, `START REPLICATION QUEUES`
+    -   `SYSTEM SYNC REPLICA`. Level: `TABLE`. Aliases: `SYNC REPLICA`
+    -   `SYSTEM RESTART REPLICA`. Level: `TABLE`. Aliases: `RESTART REPLICA`
+    -   `SYSTEM FLUSH`. Level: `GROUP`
+        -   `SYSTEM FLUSH DISTRIBUTED`. Level: `TABLE`. Aliases: `FLUSH DISTRIBUTED`
+        -   `SYSTEM FLUSH LOGS`. Level: `GLOBAL`. Aliases: `FLUSH LOGS`
+
+The `SYSTEM RELOAD EMBEDDED DICTIONARIES` privilege implicitly granted by the `SYSTEM RELOAD DICTIONARY ON *.*` privilege.
+
+### INTROSPECTION {#grant-introspection}
+
+Allows using [introspection](../../operations/optimizing-performance/sampling-query-profiler.md) functions.
+
+-   `INTROSPECTION`. Level: `GROUP`. Aliases: `INTROSPECTION FUNCTIONS`
+    -   `addressToLine`. Level: `GLOBAL`
+    -   `addressToLineWithInlines`. Level: `GLOBAL`
+    -   `addressToSymbol`. Level: `GLOBAL`
+    -   `demangle`. Level: `GLOBAL`
+
+### SOURCES {#grant-sources}
+
+Allows using external data sources. Applies to [table engines](../../engines/table-engines/index.md) and [table functions](../../sql-reference/table-functions/index.md#table-functions).
+
+-   `SOURCES`. Level: `GROUP`
+    -   `FILE`. Level: `GLOBAL`
+    -   `URL`. Level: `GLOBAL`
+    -   `REMOTE`. Level: `GLOBAL`
+    -   `YSQL`. Level: `GLOBAL`
+    -   `ODBC`. Level: `GLOBAL`
+    -   `JDBC`. Level: `GLOBAL`
+    -   `HDFS`. Level: `GLOBAL`
+    -   `S3`. Level: `GLOBAL`
+
+The `SOURCES` privilege enables use of all the sources. Also you can grant a privilege for each source individually. To use sources, you need additional privileges.
+
+Examples:
+
+-   To create a table with the [MySQL table engine](../../engines/table-engines/integrations/mysql.md), you need `CREATE TABLE (ON db.table_name)` and `MYSQL` privileges.
+-   To use the [mysql table function](../../sql-reference/table-functions/mysql.md), you need `CREATE TEMPORARY TABLE` and `MYSQL` privileges.
+
+### dictGet {#grant-dictget}
+
+-   `dictGet`. Aliases: `dictHas`, `dictGetHierarchy`, `dictIsIn`
+
+Allows a user to execute [dictGet](../../sql-reference/functions/ext-dict-functions.md#dictget), [dictHas](../../sql-reference/functions/ext-dict-functions.md#dicthas), [dictGetHierarchy](../../sql-reference/functions/ext-dict-functions.md#dictgethierarchy), [dictIsIn](../../sql-reference/functions/ext-dict-functions.md#dictisin) functions.
+
+Privilege level: `DICTIONARY`.
+
+**Examples**
+
+-   `GRANT dictGet ON mydb.mydictionary TO john`
+-   `GRANT dictGet ON mydictionary TO john`
+
+### ALL {#grant-all}
+
+Grants all the privileges on regulated entity to a user account or a role.
+
+### NONE {#grant-none}
+
+Doesn’t grant any privileges.
+
+### ADMIN OPTION {#admin-option-privilege}
+
+The `ADMIN OPTION` privilege allows a user to grant their role to another user.
+
diff --git a/docs/en/reference/sql-reference/statements/index.md b/docs/en/reference/sql-reference/statements/index.md
new file mode 100644
index 00000000000..ab51cbb330c
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/index.md
@@ -0,0 +1,31 @@
+---
+sidebar_position: 31
+sidebar_label: Statements
+---
+
+# ClickHouse SQL Statements 
+
+Statements represent various kinds of action you can perform using SQL queries. Each kind of statement has it’s own syntax and usage details that are described separately:
+
+-   [SELECT](../../sql-reference/statements/select/index.md)
+-   [INSERT INTO](../../sql-reference/statements/insert-into.md)
+-   [CREATE](../../sql-reference/statements/create/index.md)
+-   [ALTER](../../sql-reference/statements/alter/index.md)
+-   [SYSTEM](../../sql-reference/statements/system.md)
+-   [SHOW](../../sql-reference/statements/show.md)
+-   [GRANT](../../sql-reference/statements/grant.md)
+-   [REVOKE](../../sql-reference/statements/revoke.md)
+-   [ATTACH](../../sql-reference/statements/attach.md)
+-   [CHECK TABLE](../../sql-reference/statements/check-table.md)
+-   [DESCRIBE TABLE](../../sql-reference/statements/describe-table.md)
+-   [DETACH](../../sql-reference/statements/detach.md)
+-   [DROP](../../sql-reference/statements/drop.md)
+-   [EXISTS](../../sql-reference/statements/exists.md)
+-   [KILL](../../sql-reference/statements/kill.md)
+-   [OPTIMIZE](../../sql-reference/statements/optimize.md)
+-   [RENAME](../../sql-reference/statements/rename.md)
+-   [SET](../../sql-reference/statements/set.md)
+-   [SET ROLE](../../sql-reference/statements/set-role.md)
+-   [TRUNCATE](../../sql-reference/statements/truncate.md)
+-   [USE](../../sql-reference/statements/use.md)
+-   [EXPLAIN](../../sql-reference/statements/explain.md)
diff --git a/docs/en/reference/sql-reference/statements/insert-into.md b/docs/en/reference/sql-reference/statements/insert-into.md
new file mode 100644
index 00000000000..17d6ce1809b
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/insert-into.md
@@ -0,0 +1,200 @@
+---
+sidebar_position: 33
+sidebar_label: INSERT INTO
+---
+
+# INSERT INTO Statement 
+
+Inserts data into a table.
+
+**Syntax**
+
+``` sql
+INSERT INTO [db.]table [(c1, c2, c3)] VALUES (v11, v12, v13), (v21, v22, v23), ...
+```
+
+You can specify a list of columns to insert using  the `(c1, c2, c3)`. You can also use an expression with column [matcher](../../sql-reference/statements/select/index.md#asterisk) such as `*` and/or [modifiers](../../sql-reference/statements/select/index.md#select-modifiers) such as [APPLY](../../sql-reference/statements/select/index.md#apply-modifier), [EXCEPT](../../sql-reference/statements/select/index.md#except-modifier), [REPLACE](../../sql-reference/statements/select/index.md#replace-modifier).
+
+For example, consider the table:
+
+``` sql
+SHOW CREATE insert_select_testtable;
+```
+
+```text
+CREATE TABLE insert_select_testtable
+(
+    `a` Int8,
+    `b` String,
+    `c` Int8
+)
+ENGINE = MergeTree()
+ORDER BY a
+```
+
+``` sql
+INSERT INTO insert_select_testtable (*) VALUES (1, 'a', 1) ;
+```
+
+If you want to insert data in all the columns, except 'b', you need to pass so many values how many columns you chose in parenthesis then:
+
+``` sql
+INSERT INTO insert_select_testtable (* EXCEPT(b)) Values (2, 2);
+```
+
+``` sql
+SELECT * FROM insert_select_testtable;
+```
+
+```
+┌─a─┬─b─┬─c─┐
+│ 2 │   │ 2 │
+└───┴───┴───┘
+┌─a─┬─b─┬─c─┐
+│ 1 │ a │ 1 │
+└───┴───┴───┘
+```
+
+In this example, we see that the second inserted row has `a` and `c` columns filled by the passed values, and `b` filled with value by default. It is also possible to use `DEFAULT` keyword to insert default values:
+
+``` sql
+INSERT INTO insert_select_testtable VALUES (1, DEFAULT, 1) ;
+```
+
+If a list of columns does not include all existing columns, the rest of the columns are filled with:
+
+-   The values calculated from the `DEFAULT` expressions specified in the table definition.
+-   Zeros and empty strings, if `DEFAULT` expressions are not defined.
+
+Data can be passed to the INSERT in any [format](../../interfaces/formats.md#formats) supported by ClickHouse. The format must be specified explicitly in the query:
+
+``` sql
+INSERT INTO [db.]table [(c1, c2, c3)] FORMAT format_name data_set
+```
+
+For example, the following query format is identical to the basic version of INSERT … VALUES:
+
+``` sql
+INSERT INTO [db.]table [(c1, c2, c3)] FORMAT Values (v11, v12, v13), (v21, v22, v23), ...
+```
+
+ClickHouse removes all spaces and one line feed (if there is one) before the data. When forming a query, we recommend putting the data on a new line after the query operators (this is important if the data begins with spaces).
+
+Example:
+
+``` sql
+INSERT INTO t FORMAT TabSeparated
+11  Hello, world!
+22  Qwerty
+```
+
+You can insert data separately from the query by using the command-line client or the HTTP interface. For more information, see the section “[Interfaces](../../interfaces/index.md#interfaces)”.
+
+### Constraints {#constraints}
+
+If table has [constraints](../../sql-reference/statements/create/table.md#constraints), their expressions will be checked for each row of inserted data. If any of those constraints is not satisfied — server will raise an exception containing constraint name and expression, the query will be stopped.
+
+### Inserting the Results of `SELECT` {#insert_query_insert-select}
+
+**Syntax**
+
+``` sql
+INSERT INTO [db.]table [(c1, c2, c3)] SELECT ...
+```
+
+Columns are mapped according to their position in the SELECT clause. However, their names in the SELECT expression and the table for INSERT may differ. If necessary, type casting is performed.
+
+None of the data formats except Values allow setting values to expressions such as `now()`, `1 + 2`, and so on. The Values format allows limited use of expressions, but this is not recommended, because in this case inefficient code is used for their execution.
+
+Other queries for modifying data parts are not supported: `UPDATE`, `DELETE`, `REPLACE`, `MERGE`, `UPSERT`, `INSERT UPDATE`.
+However, you can delete old data using `ALTER TABLE ... DROP PARTITION`.
+
+`FORMAT` clause must be specified in the end of query if `SELECT` clause contains table function [input()](../../sql-reference/table-functions/input.md).
+
+To insert a default value instead of `NULL` into a column with not nullable data type, enable [insert_null_as_default](../../operations/settings/settings.md#insert_null_as_default) setting.
+
+### Inserting Data from a File {#inserting-data-from-a-file}
+
+**Syntax**
+
+``` sql
+INSERT INTO [db.]table [(c1, c2, c3)] FROM INFILE file_name [COMPRESSION type] FORMAT format_name
+```
+
+Use the syntax above to insert data from a file stored on a **client** side. `file_name` and `type` are string literals. Input file [format](../../interfaces/formats.md) must be set in the `FORMAT` clause. 
+
+Compressed files are supported. Compression type is detected by the extension of the file name. Or it can be explicitly specified in a `COMPRESSION` clause. Supported types are: `'none'`, `'gzip'`, `'deflate'`, `'br'`, `'xz'`, `'zstd'`, `'lz4'`, `'bz2'`.
+
+This functionality is available in the [command-line client](../../interfaces/cli.md) and [clickhouse-local](../../operations/utilities/clickhouse-local.md).
+
+**Example**
+
+Execute the following queries using [command-line client](../../interfaces/cli.md):
+
+```bash
+echo 1,A > input.csv ; echo 2,B >> input.csv
+clickhouse-client --query="CREATE TABLE table_from_file (id UInt32, text String) ENGINE=MergeTree() ORDER BY id;"
+clickhouse-client --query="INSERT INTO table_from_file FROM INFILE 'input.csv' FORMAT CSV;"
+clickhouse-client --query="SELECT * FROM table_from_file FORMAT PrettyCompact;"
+```
+
+Result:
+
+```text
+┌─id─┬─text─┐
+│  1 │ A    │
+│  2 │ B    │
+└────┴──────┘
+```
+
+### Inserting into Table Function {#inserting-into-table-function}
+
+Data can be inserted into tables referenced by [table functions](../../sql-reference/table-functions/index.md).
+
+**Syntax**
+``` sql
+INSERT INTO [TABLE] FUNCTION table_func ...
+```
+
+**Example**
+
+[remote](../../sql-reference/table-functions/index.md#remote) table function is used in the following queries:
+
+``` sql
+CREATE TABLE simple_table (id UInt32, text String) ENGINE=MergeTree() ORDER BY id;
+INSERT INTO TABLE FUNCTION remote('localhost', default.simple_table) 
+    VALUES (100, 'inserted via remote()');
+SELECT * FROM simple_table;
+```
+
+Result:
+
+``` text
+┌──id─┬─text──────────────────┐
+│ 100 │ inserted via remote() │
+└─────┴───────────────────────┘
+```
+
+### Performance Considerations {#performance-considerations}
+
+`INSERT` sorts the input data by primary key and splits them into partitions by a partition key. If you insert data into several partitions at once, it can significantly reduce the performance of the `INSERT` query. To avoid this:
+
+-   Add data in fairly large batches, such as 100,000 rows at a time.
+-   Group data by a partition key before uploading it to ClickHouse.
+
+Performance will not decrease if:
+
+-   Data is added in real time.
+-   You upload data that is usually sorted by time.
+
+It's also possible to asynchronously insert data in small but frequent inserts. The data from such insertions is combined into batches and then safely inserted into a table. To enable the asynchronous mode, switch on the [async_insert](../../operations/settings/settings.md#async-insert) setting. Note that asynchronous insertions are supported only over HTTP protocol, and deduplication is not supported for them.
+
+**See Also**
+
+-   [async_insert](../../operations/settings/settings.md#async-insert)
+-   [async_insert_threads](../../operations/settings/settings.md#async-insert-threads)
+-   [wait_for_async_insert](../../operations/settings/settings.md#wait-for-async-insert)
+-   [wait_for_async_insert_timeout](../../operations/settings/settings.md#wait-for-async-insert-timeout)
+-   [async_insert_max_data_size](../../operations/settings/settings.md#async-insert-max-data-size)
+-   [async_insert_busy_timeout_ms](../../operations/settings/settings.md#async-insert-busy-timeout-ms)
+-   [async_insert_stale_timeout_ms](../../operations/settings/settings.md#async-insert-stale-timeout-ms)
diff --git a/docs/en/reference/sql-reference/statements/kill.md b/docs/en/reference/sql-reference/statements/kill.md
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--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/kill.md
@@ -0,0 +1,70 @@
+---
+sidebar_position: 46
+sidebar_label: KILL
+---
+
+# KILL Statements {#kill-statements}
+
+There are two kinds of kill statements: to kill a query and to kill a mutation
+
+## KILL QUERY {#kill-query-statement}
+
+``` sql
+KILL QUERY [ON CLUSTER cluster]
+  WHERE <where expression to SELECT FROM system.processes query>
+  [SYNC|ASYNC|TEST]
+  [FORMAT format]
+```
+
+Attempts to forcibly terminate the currently running queries.
+The queries to terminate are selected from the system.processes table using the criteria defined in the `WHERE` clause of the `KILL` query.
+
+Examples:
+
+``` sql
+-- Forcibly terminates all queries with the specified query_id:
+KILL QUERY WHERE query_id='2-857d-4a57-9ee0-327da5d60a90'
+
+-- Synchronously terminates all queries run by 'username':
+KILL QUERY WHERE user='username' SYNC
+```
+
+Read-only users can only stop their own queries.
+
+By default, the asynchronous version of queries is used (`ASYNC`), which does not wait for confirmation that queries have stopped.
+
+The synchronous version (`SYNC`) waits for all queries to stop and displays information about each process as it stops.
+The response contains the `kill_status` column, which can take the following values:
+
+1.  `finished` – The query was terminated successfully.
+2.  `waiting` – Waiting for the query to end after sending it a signal to terminate.
+3.  The other values ​​explain why the query can’t be stopped.
+
+A test query (`TEST`) only checks the user’s rights and displays a list of queries to stop.
+
+## KILL MUTATION {#kill-mutation}
+
+``` sql
+KILL MUTATION [ON CLUSTER cluster]
+  WHERE <where expression to SELECT FROM system.mutations query>
+  [TEST]
+  [FORMAT format]
+```
+
+Tries to cancel and remove [mutations](../../sql-reference/statements/alter/index.md#alter-mutations) that are currently executing. Mutations to cancel are selected from the [`system.mutations`](../../operations/system-tables/mutations.md#system_tables-mutations) table using the filter specified by the `WHERE` clause of the `KILL` query.
+
+A test query (`TEST`) only checks the user’s rights and displays a list of mutations to stop.
+
+Examples:
+
+``` sql
+-- Cancel and remove all mutations of the single table:
+KILL MUTATION WHERE database = 'default' AND table = 'table'
+
+-- Cancel the specific mutation:
+KILL MUTATION WHERE database = 'default' AND table = 'table' AND mutation_id = 'mutation_3.txt'
+```
+
+The query is useful when a mutation is stuck and cannot finish (e.g. if some function in the mutation query throws an exception when applied to the data contained in the table).
+
+Changes already made by the mutation are not rolled back.
diff --git a/docs/en/reference/sql-reference/statements/misc.md b/docs/en/reference/sql-reference/statements/misc.md
new file mode 100644
index 00000000000..2751c5296c2
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/misc.md
@@ -0,0 +1,20 @@
+---
+toc_hidden: true
+sidebar_position: 70
+---
+
+# Miscellaneous Statements {#miscellaneous-queries}
+
+-   [ATTACH](../../sql-reference/statements/attach.md)
+-   [CHECK TABLE](../../sql-reference/statements/check-table.md)
+-   [DESCRIBE TABLE](../../sql-reference/statements/describe-table.md)
+-   [DETACH](../../sql-reference/statements/detach.md)
+-   [DROP](../../sql-reference/statements/drop.md)
+-   [EXISTS](../../sql-reference/statements/exists.md)
+-   [KILL](../../sql-reference/statements/kill.md)
+-   [OPTIMIZE](../../sql-reference/statements/optimize.md)
+-   [RENAME](../../sql-reference/statements/rename.md)
+-   [SET](../../sql-reference/statements/set.md)
+-   [SET ROLE](../../sql-reference/statements/set-role.md)
+-   [TRUNCATE](../../sql-reference/statements/truncate.md)
+-   [USE](../../sql-reference/statements/use.md)
diff --git a/docs/en/reference/sql-reference/statements/optimize.md b/docs/en/reference/sql-reference/statements/optimize.md
new file mode 100644
index 00000000000..773284a1b30
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/optimize.md
@@ -0,0 +1,200 @@
+---
+sidebar_position: 47
+sidebar_label: OPTIMIZE
+---
+
+# OPTIMIZE Statement {#misc_operations-optimize}
+
+This query tries to initialize an unscheduled merge of data parts for tables.
+
+:::warning
+`OPTIMIZE` can’t fix the `Too many parts` error.
+:::
+
+**Syntax**
+
+``` sql
+OPTIMIZE TABLE [db.]name [ON CLUSTER cluster] [PARTITION partition | PARTITION ID 'partition_id'] [FINAL] [DEDUPLICATE [BY expression]]
+```
+
+The `OPTIMIZE` query is supported for [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) family, the [MaterializedView](../../engines/table-engines/special/materializedview.md) and the [Buffer](../../engines/table-engines/special/buffer.md) engines. Other table engines aren’t supported.
+
+When `OPTIMIZE` is used with the [ReplicatedMergeTree](../../engines/table-engines/mergetree-family/replication.md) family of table engines, ClickHouse creates a task for merging and waits for execution on all replicas (if the [replication_alter_partitions_sync](../../operations/settings/settings.md#replication-alter-partitions-sync) setting is set to `2`) or on current replica (if the [replication_alter_partitions_sync](../../operations/settings/settings.md#replication-alter-partitions-sync) setting is set to `1`).
+
+-   If `OPTIMIZE` does not perform a merge for any reason, it does not notify the client. To enable notifications, use the [optimize_throw_if_noop](../../operations/settings/settings.md#setting-optimize_throw_if_noop) setting.
+-   If you specify a `PARTITION`, only the specified partition is optimized. [How to set partition expression](../../sql-reference/statements/alter/index.md#alter-how-to-specify-part-expr).
+-   If you specify `FINAL`, optimization is performed even when all the data is already in one part. Also merge is forced even if concurrent merges are performed.
+-   If you specify `DEDUPLICATE`, then completely identical rows (unless by-clause is specified) will be deduplicated (all columns are compared), it makes sense only for the MergeTree engine.
+
+You can specify how long (in seconds) to wait for inactive replicas to execute `OPTIMIZE` queries by the [replication_wait_for_inactive_replica_timeout](../../operations/settings/settings.md#replication-wait-for-inactive-replica-timeout) setting.
+
+:::note    
+If the `replication_alter_partitions_sync` is set to `2` and some replicas are not active for more than the time, specified by the `replication_wait_for_inactive_replica_timeout` setting, then an exception `UNFINISHED` is thrown.
+:::
+
+## BY expression {#by-expression}
+
+If you want to perform deduplication on custom set of columns rather than on all, you can specify list of columns explicitly or use any combination of [`*`](../../sql-reference/statements/select/index.md#asterisk), [`COLUMNS`](../../sql-reference/statements/select/index.md#columns-expression) or [`EXCEPT`](../../sql-reference/statements/select/index.md#except-modifier) expressions. The explictly written or implicitly expanded list of columns must include all columns specified in row ordering expression (both primary and sorting keys) and partitioning expression (partitioning key).
+
+:::note    
+Notice that `*` behaves just like in `SELECT`: [MATERIALIZED](../../sql-reference/statements/create/table.md#materialized) and [ALIAS](../../sql-reference/statements/create/table.md#alias) columns are not used for expansion.
+
+Also, it is an error to specify empty list of columns, or write an expression that results in an empty list of columns, or deduplicate by an `ALIAS` column.
+:::
+
+**Syntax**
+
+``` sql
+OPTIMIZE TABLE table DEDUPLICATE; -- all columns
+OPTIMIZE TABLE table DEDUPLICATE BY *; -- excludes MATERIALIZED and ALIAS columns
+OPTIMIZE TABLE table DEDUPLICATE BY colX,colY,colZ;
+OPTIMIZE TABLE table DEDUPLICATE BY * EXCEPT colX;
+OPTIMIZE TABLE table DEDUPLICATE BY * EXCEPT (colX, colY);
+OPTIMIZE TABLE table DEDUPLICATE BY COLUMNS('column-matched-by-regex');
+OPTIMIZE TABLE table DEDUPLICATE BY COLUMNS('column-matched-by-regex') EXCEPT colX;
+OPTIMIZE TABLE table DEDUPLICATE BY COLUMNS('column-matched-by-regex') EXCEPT (colX, colY);
+```
+
+**Examples**
+
+Consider the table:
+
+``` sql
+CREATE TABLE example (
+    primary_key Int32,
+    secondary_key Int32,
+    value UInt32,
+    partition_key UInt32,
+    materialized_value UInt32 MATERIALIZED 12345,
+    aliased_value UInt32 ALIAS 2,
+    PRIMARY KEY primary_key
+) ENGINE=MergeTree
+PARTITION BY partition_key
+ORDER BY (primary_key, secondary_key);
+```
+``` sql
+INSERT INTO example (primary_key, secondary_key, value, partition_key)
+VALUES (0, 0, 0, 0), (0, 0, 0, 0), (1, 1, 2, 2), (1, 1, 2, 3), (1, 1, 3, 3);
+```
+``` sql
+SELECT * FROM example;
+```
+Result:
+```
+
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           0 │             0 │     0 │             0 │
+│           0 │             0 │     0 │             0 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             2 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             3 │
+│           1 │             1 │     3 │             3 │
+└─────────────┴───────────────┴───────┴───────────────┘
+```
+
+When columns for deduplication are not specified, all of them are taken into account. Row is removed only if all values in all columns are equal to corresponding values in previous row:
+
+``` sql
+OPTIMIZE TABLE example FINAL DEDUPLICATE;
+```
+``` sql
+SELECT * FROM example;
+```
+Result:
+```
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             2 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           0 │             0 │     0 │             0 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             3 │
+│           1 │             1 │     3 │             3 │
+└─────────────┴───────────────┴───────┴───────────────┘
+```
+
+When columns are specified implicitly, the table is deduplicated by all columns that are not `ALIAS` or `MATERIALIZED`. Considering the table above, these are `primary_key`, `secondary_key`, `value`, and `partition_key` columns:
+```sql
+OPTIMIZE TABLE example FINAL DEDUPLICATE BY *;
+```
+``` sql
+SELECT * FROM example;
+```
+Result:
+```
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             2 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           0 │             0 │     0 │             0 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             3 │
+│           1 │             1 │     3 │             3 │
+└─────────────┴───────────────┴───────┴───────────────┘
+```
+
+Deduplicate by all columns that are not `ALIAS` or `MATERIALIZED` and explicitly not `value`: `primary_key`, `secondary_key`, and `partition_key` columns.
+
+``` sql
+OPTIMIZE TABLE example FINAL DEDUPLICATE BY * EXCEPT value;
+```
+``` sql
+SELECT * FROM example;
+```
+Result:
+```
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             2 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           0 │             0 │     0 │             0 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             3 │
+└─────────────┴───────────────┴───────┴───────────────┘
+```
+
+Deduplicate explicitly by `primary_key`, `secondary_key`, and `partition_key` columns:
+```sql
+OPTIMIZE TABLE example FINAL DEDUPLICATE BY primary_key, secondary_key, partition_key;
+```
+``` sql
+SELECT * FROM example;
+```
+Result:
+```
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             2 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           0 │             0 │     0 │             0 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             3 │
+└─────────────┴───────────────┴───────┴───────────────┘
+```
+
+Deduplicate by any column matching a regex: `primary_key`, `secondary_key`, and `partition_key` columns:
+```sql
+OPTIMIZE TABLE example FINAL DEDUPLICATE BY COLUMNS('.*_key');
+```
+``` sql
+SELECT * FROM example;
+```
+Result:
+```
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           0 │             0 │     0 │             0 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             2 │
+└─────────────┴───────────────┴───────┴───────────────┘
+┌─primary_key─┬─secondary_key─┬─value─┬─partition_key─┐
+│           1 │             1 │     2 │             3 │
+└─────────────┴───────────────┴───────┴───────────────┘
+```
diff --git a/docs/en/reference/sql-reference/statements/rename.md b/docs/en/reference/sql-reference/statements/rename.md
new file mode 100644
index 00000000000..b3bea3e3c37
--- /dev/null
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@@ -0,0 +1,62 @@
+---
+sidebar_position: 48
+sidebar_label: RENAME
+---
+
+# RENAME Statement {#misc_operations-rename}
+
+Renames databases, tables, or dictionaries. Several entities can be renamed in a single query.
+Note that the `RENAME` query with several entities is non-atomic operation. To swap entities names atomically, use the [EXCHANGE](./exchange.md) statement.
+
+:::note    
+The `RENAME` query is supported by the [Atomic](../../engines/database-engines/atomic.md) database engine only.
+:::
+
+**Syntax**
+
+```sql
+RENAME DATABASE|TABLE|DICTIONARY name TO new_name [,...] [ON CLUSTER cluster]
+```
+
+## RENAME DATABASE {#misc_operations-rename_database}
+
+Renames databases.
+
+**Syntax**
+
+```sql
+RENAME DATABASE atomic_database1 TO atomic_database2 [,...] [ON CLUSTER cluster]
+```
+
+## RENAME TABLE {#misc_operations-rename_table}
+
+Renames one or more tables.
+
+Renaming tables is a light operation. If you pass a different database after `TO`, the table will be moved to this database. However, the directories with databases must reside in the same file system. Otherwise, an error is returned. 
+If you rename multiple tables in one query, the operation is not atomic. It may be partially executed, and queries in other sessions may get `Table ... does not exist ...` error.
+
+**Syntax**
+
+``` sql
+RENAME TABLE [db1.]name1 TO [db2.]name2 [,...] [ON CLUSTER cluster]
+```
+
+**Example**
+
+```sql
+RENAME TABLE table_A TO table_A_bak, table_B TO table_B_bak;
+```
+
+## RENAME DICTIONARY {#rename_dictionary}
+
+Renames one or several dictionaries. This query can be used to move dictionaries between databases.
+
+**Syntax**
+
+```sql
+RENAME DICTIONARY [db0.]dict_A TO [db1.]dict_B [,...] [ON CLUSTER cluster]
+```
+
+**See Also**
+
+-   [Dictionaries](../../sql-reference/dictionaries/index.md)
diff --git a/docs/en/reference/sql-reference/statements/revoke.md b/docs/en/reference/sql-reference/statements/revoke.md
new file mode 100644
index 00000000000..1d2e86340f3
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/revoke.md
@@ -0,0 +1,48 @@
+---
+sidebar_position: 39
+sidebar_label: REVOKE
+---
+
+# REVOKE Statement {#revoke}
+
+Revokes privileges from users or roles.
+
+## Syntax {#revoke-syntax}
+
+**Revoking privileges from users**
+
+``` sql
+REVOKE [ON CLUSTER cluster_name] privilege[(column_name [,...])] [,...] ON {db.table|db.*|*.*|table|*} FROM {user | CURRENT_USER} [,...] | ALL | ALL EXCEPT {user | CURRENT_USER} [,...]
+```
+
+**Revoking roles from users**
+
+``` sql
+REVOKE [ON CLUSTER cluster_name] [ADMIN OPTION FOR] role [,...] FROM {user | role | CURRENT_USER} [,...] | ALL | ALL EXCEPT {user_name | role_name | CURRENT_USER} [,...]
+```
+
+## Description {#revoke-description}
+
+To revoke some privilege you can use a privilege of a wider scope than you plan to revoke. For example, if a user has the `SELECT (x,y)` privilege, administrator can execute `REVOKE SELECT(x,y) ...`, or `REVOKE SELECT * ...`, or even `REVOKE ALL PRIVILEGES ...` query to revoke this privilege.
+
+### Partial Revokes {#partial-revokes-dscr}
+
+You can revoke a part of a privilege. For example, if a user has the `SELECT *.*` privilege you can revoke from it a privilege to read data from some table or a database.
+
+## Examples {#revoke-example}
+
+Grant the `john` user account with a privilege to select from all the databases, excepting the `accounts` one:
+
+``` sql
+GRANT SELECT ON *.* TO john;
+REVOKE SELECT ON accounts.* FROM john;
+```
+
+Grant the `mira` user account with a privilege to select from all the columns of the `accounts.staff` table, excepting the `wage` one.
+
+``` sql
+GRANT SELECT ON accounts.staff TO mira;
+REVOKE SELECT(wage) ON accounts.staff FROM mira;
+```
+
+[Original article](https://clickhouse.com/docs/en/operations/settings/settings/)
diff --git a/docs/en/reference/sql-reference/statements/select/all.md b/docs/en/reference/sql-reference/statements/select/all.md
new file mode 100644
index 00000000000..6b35678fd92
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/all.md
@@ -0,0 +1,21 @@
+---
+sidebar_label: ALL
+---
+
+# ALL Clause {#select-all}
+
+If there are multiple matching rows in the table, then `ALL` returns all of them. `SELECT ALL` is identical to `SELECT` without `DISTINCT`. If both `ALL` and `DISTINCT` specified, exception will be thrown.
+
+
+`ALL` can also be specified inside aggregate function with the same effect(noop), for instance:
+
+```sql
+SELECT sum(ALL number) FROM numbers(10);
+```
+equals to
+
+```sql
+SELECT sum(number) FROM numbers(10);
+```
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/statements/select/all) <!--hide-->
diff --git a/docs/en/reference/sql-reference/statements/select/array-join.md b/docs/en/reference/sql-reference/statements/select/array-join.md
new file mode 100644
index 00000000000..f7fc08ae9ba
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/array-join.md
@@ -0,0 +1,300 @@
+---
+sidebar_label: ARRAY JOIN
+---
+
+# ARRAY JOIN Clause {#select-array-join-clause}
+
+It is a common operation for tables that contain an array column to produce a new table that has a column with each individual array element of that initial column, while values of other columns are duplicated. This is the basic case of what `ARRAY JOIN` clause does.
+
+Its name comes from the fact that it can be looked at as executing `JOIN` with an array or nested data structure. The intent is similar to the [arrayJoin](../../../sql-reference/functions/array-join.md#functions_arrayjoin) function, but the clause functionality is broader.
+
+Syntax:
+
+``` sql
+SELECT <expr_list>
+FROM <left_subquery>
+[LEFT] ARRAY JOIN <array>
+[WHERE|PREWHERE <expr>]
+...
+```
+
+You can specify only one `ARRAY JOIN` clause in a `SELECT` query.
+
+Supported types of `ARRAY JOIN` are listed below:
+
+-   `ARRAY JOIN` - In base case, empty arrays are not included in the result of `JOIN`.
+-   `LEFT ARRAY JOIN` - The result of `JOIN` contains rows with empty arrays. The value for an empty array is set to the default value for the array element type (usually 0, empty string or NULL).
+
+## Basic ARRAY JOIN Examples {#basic-array-join-examples}
+
+The examples below demonstrate the usage of the `ARRAY JOIN` and `LEFT ARRAY JOIN` clauses. Let’s create a table with an [Array](../../../sql-reference/data-types/array.md) type column and insert values into it:
+
+``` sql
+CREATE TABLE arrays_test
+(
+    s String,
+    arr Array(UInt8)
+) ENGINE = Memory;
+
+INSERT INTO arrays_test
+VALUES ('Hello', [1,2]), ('World', [3,4,5]), ('Goodbye', []);
+```
+
+``` text
+┌─s───────────┬─arr─────┐
+│ Hello       │ [1,2]   │
+│ World       │ [3,4,5] │
+│ Goodbye     │ []      │
+└─────────────┴─────────┘
+```
+
+The example below uses the `ARRAY JOIN` clause:
+
+``` sql
+SELECT s, arr
+FROM arrays_test
+ARRAY JOIN arr;
+```
+
+``` text
+┌─s─────┬─arr─┐
+│ Hello │   1 │
+│ Hello │   2 │
+│ World │   3 │
+│ World │   4 │
+│ World │   5 │
+└───────┴─────┘
+```
+
+The next example uses the `LEFT ARRAY JOIN` clause:
+
+``` sql
+SELECT s, arr
+FROM arrays_test
+LEFT ARRAY JOIN arr;
+```
+
+``` text
+┌─s───────────┬─arr─┐
+│ Hello       │   1 │
+│ Hello       │   2 │
+│ World       │   3 │
+│ World       │   4 │
+│ World       │   5 │
+│ Goodbye     │   0 │
+└─────────────┴─────┘
+```
+
+## Using Aliases {#using-aliases}
+
+An alias can be specified for an array in the `ARRAY JOIN` clause. In this case, an array item can be accessed by this alias, but the array itself is accessed by the original name. Example:
+
+``` sql
+SELECT s, arr, a
+FROM arrays_test
+ARRAY JOIN arr AS a;
+```
+
+``` text
+┌─s─────┬─arr─────┬─a─┐
+│ Hello │ [1,2]   │ 1 │
+│ Hello │ [1,2]   │ 2 │
+│ World │ [3,4,5] │ 3 │
+│ World │ [3,4,5] │ 4 │
+│ World │ [3,4,5] │ 5 │
+└───────┴─────────┴───┘
+```
+
+Using aliases, you can perform `ARRAY JOIN` with an external array. For example:
+
+``` sql
+SELECT s, arr_external
+FROM arrays_test
+ARRAY JOIN [1, 2, 3] AS arr_external;
+```
+
+``` text
+┌─s───────────┬─arr_external─┐
+│ Hello       │            1 │
+│ Hello       │            2 │
+│ Hello       │            3 │
+│ World       │            1 │
+│ World       │            2 │
+│ World       │            3 │
+│ Goodbye     │            1 │
+│ Goodbye     │            2 │
+│ Goodbye     │            3 │
+└─────────────┴──────────────┘
+```
+
+Multiple arrays can be comma-separated in the `ARRAY JOIN` clause. In this case, `JOIN` is performed with them simultaneously (the direct sum, not the cartesian product). Note that all the arrays must have the same size by default. Example:
+
+``` sql
+SELECT s, arr, a, num, mapped
+FROM arrays_test
+ARRAY JOIN arr AS a, arrayEnumerate(arr) AS num, arrayMap(x -> x + 1, arr) AS mapped;
+```
+
+``` text
+┌─s─────┬─arr─────┬─a─┬─num─┬─mapped─┐
+│ Hello │ [1,2]   │ 1 │   1 │      2 │
+│ Hello │ [1,2]   │ 2 │   2 │      3 │
+│ World │ [3,4,5] │ 3 │   1 │      4 │
+│ World │ [3,4,5] │ 4 │   2 │      5 │
+│ World │ [3,4,5] │ 5 │   3 │      6 │
+└───────┴─────────┴───┴─────┴────────┘
+```
+
+The example below uses the [arrayEnumerate](../../../sql-reference/functions/array-functions.md#array_functions-arrayenumerate) function:
+
+``` sql
+SELECT s, arr, a, num, arrayEnumerate(arr)
+FROM arrays_test
+ARRAY JOIN arr AS a, arrayEnumerate(arr) AS num;
+```
+
+``` text
+┌─s─────┬─arr─────┬─a─┬─num─┬─arrayEnumerate(arr)─┐
+│ Hello │ [1,2]   │ 1 │   1 │ [1,2]               │
+│ Hello │ [1,2]   │ 2 │   2 │ [1,2]               │
+│ World │ [3,4,5] │ 3 │   1 │ [1,2,3]             │
+│ World │ [3,4,5] │ 4 │   2 │ [1,2,3]             │
+│ World │ [3,4,5] │ 5 │   3 │ [1,2,3]             │
+└───────┴─────────┴───┴─────┴─────────────────────┘
+```
+Multiple arrays with different sizes can be joined by using: `SETTINGS enable_unaligned_array_join = 1`. Example:
+
+```sql
+SELECT s, arr, a, b 
+FROM arrays_test ARRAY JOIN arr as a, [['a','b'],['c']] as b 
+SETTINGS enable_unaligned_array_join = 1;
+```
+
+```text
+┌─s───────┬─arr─────┬─a─┬─b─────────┐
+│ Hello   │ [1,2]   │ 1 │ ['a','b'] │
+│ Hello   │ [1,2]   │ 2 │ ['c']     │
+│ World   │ [3,4,5] │ 3 │ ['a','b'] │
+│ World   │ [3,4,5] │ 4 │ ['c']     │
+│ World   │ [3,4,5] │ 5 │ []        │
+│ Goodbye │ []      │ 0 │ ['a','b'] │
+│ Goodbye │ []      │ 0 │ ['c']     │
+└─────────┴─────────┴───┴───────────┘
+```
+
+## ARRAY JOIN with Nested Data Structure {#array-join-with-nested-data-structure}
+
+`ARRAY JOIN` also works with [nested data structures](../../../sql-reference/data-types/nested-data-structures/nested.md):
+
+``` sql
+CREATE TABLE nested_test
+(
+    s String,
+    nest Nested(
+    x UInt8,
+    y UInt32)
+) ENGINE = Memory;
+
+INSERT INTO nested_test
+VALUES ('Hello', [1,2], [10,20]), ('World', [3,4,5], [30,40,50]), ('Goodbye', [], []);
+```
+
+``` text
+┌─s───────┬─nest.x──┬─nest.y─────┐
+│ Hello   │ [1,2]   │ [10,20]    │
+│ World   │ [3,4,5] │ [30,40,50] │
+│ Goodbye │ []      │ []         │
+└─────────┴─────────┴────────────┘
+```
+
+``` sql
+SELECT s, `nest.x`, `nest.y`
+FROM nested_test
+ARRAY JOIN nest;
+```
+
+``` text
+┌─s─────┬─nest.x─┬─nest.y─┐
+│ Hello │      1 │     10 │
+│ Hello │      2 │     20 │
+│ World │      3 │     30 │
+│ World │      4 │     40 │
+│ World │      5 │     50 │
+└───────┴────────┴────────┘
+```
+
+When specifying names of nested data structures in `ARRAY JOIN`, the meaning is the same as `ARRAY JOIN` with all the array elements that it consists of. Examples are listed below:
+
+``` sql
+SELECT s, `nest.x`, `nest.y`
+FROM nested_test
+ARRAY JOIN `nest.x`, `nest.y`;
+```
+
+``` text
+┌─s─────┬─nest.x─┬─nest.y─┐
+│ Hello │      1 │     10 │
+│ Hello │      2 │     20 │
+│ World │      3 │     30 │
+│ World │      4 │     40 │
+│ World │      5 │     50 │
+└───────┴────────┴────────┘
+```
+
+This variation also makes sense:
+
+``` sql
+SELECT s, `nest.x`, `nest.y`
+FROM nested_test
+ARRAY JOIN `nest.x`;
+```
+
+``` text
+┌─s─────┬─nest.x─┬─nest.y─────┐
+│ Hello │      1 │ [10,20]    │
+│ Hello │      2 │ [10,20]    │
+│ World │      3 │ [30,40,50] │
+│ World │      4 │ [30,40,50] │
+│ World │      5 │ [30,40,50] │
+└───────┴────────┴────────────┘
+```
+
+An alias may be used for a nested data structure, in order to select either the `JOIN` result or the source array. Example:
+
+``` sql
+SELECT s, `n.x`, `n.y`, `nest.x`, `nest.y`
+FROM nested_test
+ARRAY JOIN nest AS n;
+```
+
+``` text
+┌─s─────┬─n.x─┬─n.y─┬─nest.x──┬─nest.y─────┐
+│ Hello │   1 │  10 │ [1,2]   │ [10,20]    │
+│ Hello │   2 │  20 │ [1,2]   │ [10,20]    │
+│ World │   3 │  30 │ [3,4,5] │ [30,40,50] │
+│ World │   4 │  40 │ [3,4,5] │ [30,40,50] │
+│ World │   5 │  50 │ [3,4,5] │ [30,40,50] │
+└───────┴─────┴─────┴─────────┴────────────┘
+```
+
+Example of using the [arrayEnumerate](../../../sql-reference/functions/array-functions.md#array_functions-arrayenumerate) function:
+
+``` sql
+SELECT s, `n.x`, `n.y`, `nest.x`, `nest.y`, num
+FROM nested_test
+ARRAY JOIN nest AS n, arrayEnumerate(`nest.x`) AS num;
+```
+
+``` text
+┌─s─────┬─n.x─┬─n.y─┬─nest.x──┬─nest.y─────┬─num─┐
+│ Hello │   1 │  10 │ [1,2]   │ [10,20]    │   1 │
+│ Hello │   2 │  20 │ [1,2]   │ [10,20]    │   2 │
+│ World │   3 │  30 │ [3,4,5] │ [30,40,50] │   1 │
+│ World │   4 │  40 │ [3,4,5] │ [30,40,50] │   2 │
+│ World │   5 │  50 │ [3,4,5] │ [30,40,50] │   3 │
+└───────┴─────┴─────┴─────────┴────────────┴─────┘
+```
+
+## Implementation Details {#implementation-details}
+
+The query execution order is optimized when running `ARRAY JOIN`. Although `ARRAY JOIN` must always be specified before the [WHERE](../../../sql-reference/statements/select/where.md)/[PREWHERE](../../../sql-reference/statements/select/prewhere.md) clause in a query, technically they can be performed in any order, unless result of `ARRAY JOIN` is used for filtering. The processing order is controlled by the query optimizer.
diff --git a/docs/en/reference/sql-reference/statements/select/distinct.md b/docs/en/reference/sql-reference/statements/select/distinct.md
new file mode 100644
index 00000000000..898de4730ae
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/distinct.md
@@ -0,0 +1,109 @@
+---
+sidebar_label: DISTINCT
+---
+
+# DISTINCT Clause {#select-distinct}
+
+If `SELECT DISTINCT` is specified, only unique rows will remain in a query result. Thus only a single row will remain out of all the sets of fully matching rows in the result.
+
+You can specify the list of columns that must have unique values: `SELECT DISTINCT ON (column1, column2,...)`. If the columns are not specified, all of them are taken into consideration.
+
+Consider the table:
+
+```text
+┌─a─┬─b─┬─c─┐
+│ 1 │ 1 │ 1 │
+│ 1 │ 1 │ 1 │
+│ 2 │ 2 │ 2 │
+│ 2 │ 2 │ 2 │
+│ 1 │ 1 │ 2 │
+│ 1 │ 2 │ 2 │
+└───┴───┴───┘
+```
+
+Using `DISTINCT` without specifying columns:
+
+```sql
+SELECT DISTINCT * FROM t1;
+```
+
+```text
+┌─a─┬─b─┬─c─┐
+│ 1 │ 1 │ 1 │
+│ 2 │ 2 │ 2 │
+│ 1 │ 1 │ 2 │
+│ 1 │ 2 │ 2 │
+└───┴───┴───┘
+```
+
+Using `DISTINCT` with specified columns:
+
+```sql
+SELECT DISTINCT ON (a,b) * FROM t1;
+```
+
+```text
+┌─a─┬─b─┬─c─┐
+│ 1 │ 1 │ 1 │
+│ 2 │ 2 │ 2 │
+│ 1 │ 2 │ 2 │
+└───┴───┴───┘
+```
+
+## DISTINCT and ORDER BY {#distinct-orderby}
+
+ClickHouse supports using the `DISTINCT` and `ORDER BY` clauses for different columns in one query. The `DISTINCT` clause is executed before the `ORDER BY` clause.
+
+Consider the table:
+
+``` text
+┌─a─┬─b─┐
+│ 2 │ 1 │
+│ 1 │ 2 │
+│ 3 │ 3 │
+│ 2 │ 4 │
+└───┴───┘
+```
+
+Selecting data:
+
+```sql
+SELECT DISTINCT a FROM t1 ORDER BY b ASC;
+```
+
+``` text
+┌─a─┐
+│ 2 │
+│ 1 │
+│ 3 │
+└───┘
+```
+Selecting data with the different sorting direction:
+
+```sql
+SELECT DISTINCT a FROM t1 ORDER BY b DESC;
+```
+
+``` text
+┌─a─┐
+│ 3 │
+│ 1 │
+│ 2 │
+└───┘
+```
+
+Row `2, 4` was cut before sorting.
+
+Take this implementation specificity into account when programming queries.
+
+## Null Processing {#null-processing}
+
+`DISTINCT` works with [NULL](../../../sql-reference/syntax.md#null-literal) as if `NULL` were a specific value, and `NULL==NULL`. In other words, in the `DISTINCT` results, different combinations with `NULL` occur only once. It differs from `NULL` processing in most other contexts.
+
+## Alternatives {#alternatives}
+
+It is possible to obtain the same result by applying [GROUP BY](../../../sql-reference/statements/select/group-by.md) across the same set of values as specified as `SELECT` clause, without using any aggregate functions. But there are few differences from `GROUP BY` approach:
+
+-   `DISTINCT` can be applied together with `GROUP BY`.
+-   When [ORDER BY](../../../sql-reference/statements/select/order-by.md) is omitted and [LIMIT](../../../sql-reference/statements/select/limit.md) is defined, the query stops running immediately after the required number of different rows has been read.
+-   Data blocks are output as they are processed, without waiting for the entire query to finish running.
diff --git a/docs/en/reference/sql-reference/statements/select/except.md b/docs/en/reference/sql-reference/statements/select/except.md
new file mode 100644
index 00000000000..dcaefd67ca9
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/except.md
@@ -0,0 +1,69 @@
+---
+sidebar_label: EXCEPT
+---
+
+# EXCEPT Clause {#except-clause}
+
+The `EXCEPT` clause returns only those rows that result from the first query without the second. The queries must match the number of columns, order, and type. The result of `EXCEPT` can contain duplicate rows.
+
+Multiple `EXCEPT` statements are executed left to right if parenthesis are not specified. The `EXCEPT` operator has the same priority as the `UNION` clause and lower priority than the `INTERSECT` clause.
+
+``` sql
+SELECT column1 [, column2 ]
+FROM table1
+[WHERE condition]
+
+EXCEPT
+
+SELECT column1 [, column2 ]
+FROM table2
+[WHERE condition]
+
+```
+The condition could be any expression based on your requirements.
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT number FROM numbers(1,10) EXCEPT SELECT number FROM numbers(3,6);
+```
+
+Result:
+
+``` text
+┌─number─┐
+│      1 │
+│      2 │
+│      9 │
+│     10 │
+└────────┘
+```
+
+Query:
+
+``` sql
+CREATE TABLE t1(one String, two String, three String) ENGINE=Memory();
+CREATE TABLE t2(four String, five String, six String) ENGINE=Memory();
+
+INSERT INTO t1 VALUES ('q', 'm', 'b'), ('s', 'd', 'f'), ('l', 'p', 'o'), ('s', 'd', 'f'), ('s', 'd', 'f'), ('k', 't', 'd'), ('l', 'p', 'o');
+INSERT INTO t2 VALUES ('q', 'm', 'b'), ('b', 'd', 'k'), ('s', 'y', 't'), ('s', 'd', 'f'), ('m', 'f', 'o'), ('k', 'k', 'd');
+
+SELECT * FROM t1 EXCEPT SELECT * FROM t2;
+```
+
+Result:
+
+``` text
+┌─one─┬─two─┬─three─┐
+│ l   │ p   │ o     │
+│ k   │ t   │ d     │
+│ l   │ p   │ o     │
+└─────┴─────┴───────┘
+```
+
+**See Also**
+
+-   [UNION](union.md#union-clause)
+-   [INTERSECT](intersect.md#intersect-clause)
diff --git a/docs/en/reference/sql-reference/statements/select/format.md b/docs/en/reference/sql-reference/statements/select/format.md
new file mode 100644
index 00000000000..a7936509ad5
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/format.md
@@ -0,0 +1,17 @@
+---
+sidebar_label: FORMAT
+---
+
+# FORMAT Clause {#format-clause}
+
+ClickHouse supports a wide range of [serialization formats](../../../interfaces/formats.md) that can be used on query results among other things. There are multiple ways to choose a format for `SELECT` output, one of them is to specify `FORMAT format` at the end of query to get resulting data in any specific format.
+
+Specific format might be used either for convenience, integration with other systems or performance gain.
+
+## Default Format {#default-format}
+
+If the `FORMAT` clause is omitted, the default format is used, which depends on both the settings and the interface used for accessing the ClickHouse server. For the [HTTP interface](../../../interfaces/http.md) and the [command-line client](../../../interfaces/cli.md) in batch mode, the default format is `TabSeparated`. For the command-line client in interactive mode, the default format is `PrettyCompact` (it produces compact human-readable tables).
+
+## Implementation Details {#implementation-details}
+
+When using the command-line client, data is always passed over the network in an internal efficient format (`Native`). The client independently interprets the `FORMAT` clause of the query and formats the data itself (thus relieving the network and the server from the extra load).
diff --git a/docs/en/reference/sql-reference/statements/select/from.md b/docs/en/reference/sql-reference/statements/select/from.md
new file mode 100644
index 00000000000..93f47c6c65b
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/from.md
@@ -0,0 +1,45 @@
+---
+sidebar_label: FROM
+---
+
+# FROM Clause {#select-from}
+
+The `FROM` clause specifies the source to read data from:
+
+-   [Table](../../../engines/table-engines/index.md)
+-   [Subquery](../../../sql-reference/statements/select/index.md) 
+-   [Table function](../../../sql-reference/table-functions/index.md#table-functions)
+
+[JOIN](../../../sql-reference/statements/select/join.md) and [ARRAY JOIN](../../../sql-reference/statements/select/array-join.md) clauses may also be used to extend the functionality of the `FROM` clause.
+
+Subquery is another `SELECT` query that may be specified in parenthesis inside `FROM` clause.
+
+`FROM` clause can contain multiple data sources, separated by commas, which is equivalent of performing [CROSS JOIN](../../../sql-reference/statements/select/join.md) on them.
+
+## FINAL Modifier {#select-from-final}
+
+When `FINAL` is specified, ClickHouse fully merges the data before returning the result and thus performs all data transformations that happen during merges for the given table engine.
+
+It is applicable when selecting data from tables that use the [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md)-engine family. Also supported for:
+
+-   [Replicated](../../../engines/table-engines/mergetree-family/replication.md) versions of `MergeTree` engines.
+-   [View](../../../engines/table-engines/special/view.md), [Buffer](../../../engines/table-engines/special/buffer.md), [Distributed](../../../engines/table-engines/special/distributed.md), and [MaterializedView](../../../engines/table-engines/special/materializedview.md) engines that operate over other engines, provided they were created over `MergeTree`-engine tables.
+
+Now `SELECT` queries with `FINAL` are executed in parallel and slightly faster. But there are drawbacks (see below). The [max_final_threads](../../../operations/settings/settings.md#max-final-threads) setting limits the number of threads used.
+
+### Drawbacks {#drawbacks}
+
+Queries that use `FINAL` are executed slightly slower than similar queries that do not, because:
+
+-   Data is merged during query execution.
+-   Queries with `FINAL` read primary key columns in addition to the columns specified in the query.
+
+**In most cases, avoid using `FINAL`.** The common approach is to use different queries that assume the background processes of the `MergeTree` engine have’t happened yet and deal with it by applying aggregation (for example, to discard duplicates).
+
+## Implementation Details {#implementation-details}
+
+If the `FROM` clause is omitted, data will be read from the `system.one` table.
+The `system.one` table contains exactly one row (this table fulfills the same purpose as the DUAL table found in other DBMSs).
+
+To execute a query, all the columns listed in the query are extracted from the appropriate table. Any columns not needed for the external query are thrown out of the subqueries.
+If a query does not list any columns (for example, `SELECT count() FROM t`), some column is extracted from the table anyway (the smallest one is preferred), in order to calculate the number of rows.
diff --git a/docs/en/reference/sql-reference/statements/select/group-by.md b/docs/en/reference/sql-reference/statements/select/group-by.md
new file mode 100644
index 00000000000..b08647271f1
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/group-by.md
@@ -0,0 +1,286 @@
+---
+sidebar_label: GROUP BY
+---
+
+# GROUP BY Clause {#select-group-by-clause}
+
+`GROUP BY` clause switches the `SELECT` query into an aggregation mode, which works as follows:
+
+-   `GROUP BY` clause contains a list of expressions (or a single expression, which is considered to be the list of length one). This list acts as a “grouping key”, while each individual expression will be referred to as a “key expression”.
+-   All the expressions in the [SELECT](../../../sql-reference/statements/select/index.md), [HAVING](../../../sql-reference/statements/select/having.md), and [ORDER BY](../../../sql-reference/statements/select/order-by.md) clauses **must** be calculated based on key expressions **or** on [aggregate functions](../../../sql-reference/aggregate-functions/index.md) over non-key expressions (including plain columns). In other words, each column selected from the table must be used either in a key expression or inside an aggregate function, but not both.
+-   Result of aggregating `SELECT` query will contain as many rows as there were unique values of “grouping key” in source table. Usually this signficantly reduces the row count, often by orders of magnitude, but not necessarily: row count stays the same if all “grouping key” values were distinct.
+
+When you want to group data in the table by column numbers instead of column names, enable the setting [enable_positional_arguments](../../../operations/settings/settings.md#enable-positional-arguments).
+
+:::note    
+There’s an additional way to run aggregation over a table. If a query contains table columns only inside aggregate functions, the `GROUP BY clause` can be omitted, and aggregation by an empty set of keys is assumed. Such queries always return exactly one row.
+:::
+
+## NULL Processing {#null-processing}
+
+For grouping, ClickHouse interprets [NULL](../../../sql-reference/syntax.md#null-literal) as a value, and `NULL==NULL`. It differs from `NULL` processing in most other contexts.
+
+Here’s an example to show what this means.
+
+Assume you have this table:
+
+``` text
+┌─x─┬────y─┐
+│ 1 │    2 │
+│ 2 │ ᴺᵁᴸᴸ │
+│ 3 │    2 │
+│ 3 │    3 │
+│ 3 │ ᴺᵁᴸᴸ │
+└───┴──────┘
+```
+
+The query `SELECT sum(x), y FROM t_null_big GROUP BY y` results in:
+
+``` text
+┌─sum(x)─┬────y─┐
+│      4 │    2 │
+│      3 │    3 │
+│      5 │ ᴺᵁᴸᴸ │
+└────────┴──────┘
+```
+
+You can see that `GROUP BY` for `y = NULL` summed up `x`, as if `NULL` is this value.
+
+If you pass several keys to `GROUP BY`, the result will give you all the combinations of the selection, as if `NULL` were a specific value.
+
+## WITH ROLLUP Modifier {#with-rollup-modifier}
+
+`WITH ROLLUP` modifier is used to calculate subtotals for the key expressions, based on their order in the `GROUP BY` list. The subtotals rows are added after the result table.
+
+The subtotals are calculated in the reverse order: at first subtotals are calculated for the last key expression in the list, then for the previous one, and so on up to the first key expression.
+
+In the subtotals rows the values of already "grouped" key expressions are set to `0` or empty line.
+
+:::note    
+Mind that [HAVING](../../../sql-reference/statements/select/having.md) clause can affect the subtotals results.
+:::
+
+**Example**
+
+Consider the table t:
+
+```text
+┌─year─┬─month─┬─day─┐
+│ 2019 │     1 │   5 │
+│ 2019 │     1 │  15 │
+│ 2020 │     1 │   5 │
+│ 2020 │     1 │  15 │
+│ 2020 │    10 │   5 │
+│ 2020 │    10 │  15 │
+└──────┴───────┴─────┘
+```
+
+Query:
+
+```sql
+SELECT year, month, day, count(*) FROM t GROUP BY year, month, day WITH ROLLUP;
+```
+As `GROUP BY` section has three key expressions, the result contains four tables with subtotals "rolled up" from right to left:
+
+- `GROUP BY year, month, day`;
+- `GROUP BY year, month` (and `day` column is filled with zeros);
+- `GROUP BY year` (now `month, day` columns are both filled with zeros);
+- and totals (and all three key expression columns are zeros).
+
+```text
+┌─year─┬─month─┬─day─┬─count()─┐
+│ 2020 │    10 │  15 │       1 │
+│ 2020 │     1 │   5 │       1 │
+│ 2019 │     1 │   5 │       1 │
+│ 2020 │     1 │  15 │       1 │
+│ 2019 │     1 │  15 │       1 │
+│ 2020 │    10 │   5 │       1 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│ 2019 │     1 │   0 │       2 │
+│ 2020 │     1 │   0 │       2 │
+│ 2020 │    10 │   0 │       2 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│ 2019 │     0 │   0 │       2 │
+│ 2020 │     0 │   0 │       4 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│    0 │     0 │   0 │       6 │
+└──────┴───────┴─────┴─────────┘
+```
+
+## WITH CUBE Modifier {#with-cube-modifier}
+
+`WITH CUBE` modifier is used to calculate subtotals for every combination of the key expressions in the `GROUP BY` list. The subtotals rows are added after the result table.
+
+In the subtotals rows the values of all "grouped" key expressions are set to `0` or empty line.
+
+:::note    
+Mind that [HAVING](../../../sql-reference/statements/select/having.md) clause can affect the subtotals results.
+:::
+
+**Example**
+
+Consider the table t:
+
+```text
+┌─year─┬─month─┬─day─┐
+│ 2019 │     1 │   5 │
+│ 2019 │     1 │  15 │
+│ 2020 │     1 │   5 │
+│ 2020 │     1 │  15 │
+│ 2020 │    10 │   5 │
+│ 2020 │    10 │  15 │
+└──────┴───────┴─────┘
+```
+
+Query:
+
+```sql
+SELECT year, month, day, count(*) FROM t GROUP BY year, month, day WITH CUBE;
+```
+
+As `GROUP BY` section has three key expressions, the result contains eight tables with subtotals for all key expression combinations:
+
+- `GROUP BY year, month, day`
+- `GROUP BY year, month`
+- `GROUP BY year, day`
+- `GROUP BY year`
+- `GROUP BY month, day`
+- `GROUP BY month`
+- `GROUP BY day`
+- and totals.
+
+Columns, excluded from `GROUP BY`, are filled with zeros.
+
+```text
+┌─year─┬─month─┬─day─┬─count()─┐
+│ 2020 │    10 │  15 │       1 │
+│ 2020 │     1 │   5 │       1 │
+│ 2019 │     1 │   5 │       1 │
+│ 2020 │     1 │  15 │       1 │
+│ 2019 │     1 │  15 │       1 │
+│ 2020 │    10 │   5 │       1 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│ 2019 │     1 │   0 │       2 │
+│ 2020 │     1 │   0 │       2 │
+│ 2020 │    10 │   0 │       2 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│ 2020 │     0 │   5 │       2 │
+│ 2019 │     0 │   5 │       1 │
+│ 2020 │     0 │  15 │       2 │
+│ 2019 │     0 │  15 │       1 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│ 2019 │     0 │   0 │       2 │
+│ 2020 │     0 │   0 │       4 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│    0 │     1 │   5 │       2 │
+│    0 │    10 │  15 │       1 │
+│    0 │    10 │   5 │       1 │
+│    0 │     1 │  15 │       2 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│    0 │     1 │   0 │       4 │
+│    0 │    10 │   0 │       2 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│    0 │     0 │   5 │       3 │
+│    0 │     0 │  15 │       3 │
+└──────┴───────┴─────┴─────────┘
+┌─year─┬─month─┬─day─┬─count()─┐
+│    0 │     0 │   0 │       6 │
+└──────┴───────┴─────┴─────────┘
+```
+
+
+## WITH TOTALS Modifier {#with-totals-modifier}
+
+If the `WITH TOTALS` modifier is specified, another row will be calculated. This row will have key columns containing default values (zeros or empty lines), and columns of aggregate functions with the values calculated across all the rows (the “total” values).
+
+This extra row is only produced in `JSON*`, `TabSeparated*`, and `Pretty*` formats, separately from the other rows:
+
+-   In `JSON*` formats, this row is output as a separate ‘totals’ field.
+-   In `TabSeparated*` formats, the row comes after the main result, preceded by an empty row (after the other data).
+-   In `Pretty*` formats, the row is output as a separate table after the main result.
+-   In the other formats it is not available.
+
+:::note    
+totals is output in the results of `SELECT` queries, and is not output in `INSERT INTO ... SELECT`. 
+:::
+
+`WITH TOTALS` can be run in different ways when [HAVING](../../../sql-reference/statements/select/having.md) is present. The behavior depends on the `totals_mode` setting.
+
+### Configuring Totals Processing {#configuring-totals-processing}
+
+By default, `totals_mode = 'before_having'`. In this case, ‘totals’ is calculated across all rows, including the ones that do not pass through HAVING and `max_rows_to_group_by`.
+
+The other alternatives include only the rows that pass through HAVING in ‘totals’, and behave differently with the setting `max_rows_to_group_by` and `group_by_overflow_mode = 'any'`.
+
+`after_having_exclusive` – Don’t include rows that didn’t pass through `max_rows_to_group_by`. In other words, ‘totals’ will have less than or the same number of rows as it would if `max_rows_to_group_by` were omitted.
+
+`after_having_inclusive` – Include all the rows that didn’t pass through ‘max_rows_to_group_by’ in ‘totals’. In other words, ‘totals’ will have more than or the same number of rows as it would if `max_rows_to_group_by` were omitted.
+
+`after_having_auto` – Count the number of rows that passed through HAVING. If it is more than a certain amount (by default, 50%), include all the rows that didn’t pass through ‘max_rows_to_group_by’ in ‘totals’. Otherwise, do not include them.
+
+`totals_auto_threshold` – By default, 0.5. The coefficient for `after_having_auto`.
+
+If `max_rows_to_group_by` and `group_by_overflow_mode = 'any'` are not used, all variations of `after_having` are the same, and you can use any of them (for example, `after_having_auto`).
+
+You can use `WITH TOTALS` in subqueries, including subqueries in the [JOIN](../../../sql-reference/statements/select/join.md) clause (in this case, the respective total values are combined).
+
+## Examples {#examples}
+
+Example:
+
+``` sql
+SELECT
+    count(),
+    median(FetchTiming > 60 ? 60 : FetchTiming),
+    count() - sum(Refresh)
+FROM hits
+```
+
+As opposed to MySQL (and conforming to standard SQL), you can’t get some value of some column that is not in a key or aggregate function (except constant expressions). To work around this, you can use the ‘any’ aggregate function (get the first encountered value) or ‘min/max’.
+
+Example:
+
+``` sql
+SELECT
+    domainWithoutWWW(URL) AS domain,
+    count(),
+    any(Title) AS title -- getting the first occurred page header for each domain.
+FROM hits
+GROUP BY domain
+```
+
+For every different key value encountered, `GROUP BY` calculates a set of aggregate function values.
+
+## Implementation Details {#implementation-details}
+
+Aggregation is one of the most important features of a column-oriented DBMS, and thus it’s implementation is one of the most heavily optimized parts of ClickHouse. By default, aggregation is done in memory using a hash-table. It has 40+ specializations that are chosen automatically depending on “grouping key” data types.
+
+### GROUP BY Optimization Depending on Table Sorting Key {#aggregation-in-order}
+
+The aggregation can be performed more effectively, if a table is sorted by some key, and `GROUP BY` expression contains at least prefix of sorting key or injective functions. In this case when a new key is read from table, the in-between result of aggregation can be finalized and sent to client. This behaviour is switched on by the [optimize_aggregation_in_order](../../../operations/settings/settings.md#optimize_aggregation_in_order) setting. Such optimization reduces memory usage during aggregation, but in some cases may slow down the query execution.
+
+### GROUP BY in External Memory {#select-group-by-in-external-memory}
+
+You can enable dumping temporary data to the disk to restrict memory usage during `GROUP BY`.
+The [max_bytes_before_external_group_by](../../../operations/settings/settings.md#settings-max_bytes_before_external_group_by) setting determines the threshold RAM consumption for dumping `GROUP BY` temporary data to the file system. If set to 0 (the default), it is disabled.
+
+When using `max_bytes_before_external_group_by`, we recommend that you set `max_memory_usage` about twice as high. This is necessary because there are two stages to aggregation: reading the data and forming intermediate data (1) and merging the intermediate data (2). Dumping data to the file system can only occur during stage 1. If the temporary data wasn’t dumped, then stage 2 might require up to the same amount of memory as in stage 1.
+
+For example, if [max_memory_usage](../../../operations/settings/settings.md#settings_max_memory_usage) was set to 10000000000 and you want to use external aggregation, it makes sense to set `max_bytes_before_external_group_by` to 10000000000, and `max_memory_usage` to 20000000000. When external aggregation is triggered (if there was at least one dump of temporary data), maximum consumption of RAM is only slightly more than `max_bytes_before_external_group_by`.
+
+With distributed query processing, external aggregation is performed on remote servers. In order for the requester server to use only a small amount of RAM, set `distributed_aggregation_memory_efficient` to 1.
+
+When merging data flushed to the disk, as well as when merging results from remote servers when the `distributed_aggregation_memory_efficient` setting is enabled, consumes up to `1/256 * the_number_of_threads` from the total amount of RAM.
+
+When external aggregation is enabled, if there was less than `max_bytes_before_external_group_by` of data (i.e. data was not flushed), the query runs just as fast as without external aggregation. If any temporary data was flushed, the run time will be several times longer (approximately three times).
+
+If you have an [ORDER BY](../../../sql-reference/statements/select/order-by.md) with a [LIMIT](../../../sql-reference/statements/select/limit.md) after `GROUP BY`, then the amount of used RAM depends on the amount of data in `LIMIT`, not in the whole table. But if the `ORDER BY` does not have `LIMIT`, do not forget to enable external sorting (`max_bytes_before_external_sort`).
diff --git a/docs/en/reference/sql-reference/statements/select/having.md b/docs/en/reference/sql-reference/statements/select/having.md
new file mode 100644
index 00000000000..9aee0cf4d63
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/having.md
@@ -0,0 +1,13 @@
+---
+sidebar_label: HAVING
+---
+
+# HAVING Clause {#having-clause}
+
+Allows filtering the aggregation results produced by [GROUP BY](../../../sql-reference/statements/select/group-by.md). It is similar to the [WHERE](../../../sql-reference/statements/select/where.md) clause, but the difference is that `WHERE` is performed before aggregation, while `HAVING` is performed after it.
+
+It is possible to reference aggregation results from `SELECT` clause in `HAVING` clause by their alias. Alternatively, `HAVING` clause can filter on results of additional aggregates that are not returned in query results.
+
+## Limitations {#limitations}
+
+`HAVING` can’t be used if aggregation is not performed. Use `WHERE` instead.
diff --git a/docs/en/reference/sql-reference/statements/select/index.md b/docs/en/reference/sql-reference/statements/select/index.md
new file mode 100644
index 00000000000..50dd8fecf3a
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/index.md
@@ -0,0 +1,285 @@
+---
+sidebar_position: 32
+sidebar_label: SELECT
+---
+
+# SELECT Query 
+
+`SELECT` queries perform data retrieval. By default, the requested data is returned to the client, while in conjunction with [INSERT INTO](../../../sql-reference/statements/insert-into.md) it can be forwarded to a different table.
+
+## Syntax {#syntax}
+
+``` sql
+[WITH expr_list|(subquery)]
+SELECT [DISTINCT [ON (column1, column2, ...)]] expr_list
+[FROM [db.]table | (subquery) | table_function] [FINAL]
+[SAMPLE sample_coeff]
+[ARRAY JOIN ...]
+[GLOBAL] [ANY|ALL|ASOF] [INNER|LEFT|RIGHT|FULL|CROSS] [OUTER|SEMI|ANTI] JOIN (subquery)|table (ON <expr_list>)|(USING <column_list>)
+[PREWHERE expr]
+[WHERE expr]
+[GROUP BY expr_list] [WITH ROLLUP|WITH CUBE] [WITH TOTALS]
+[HAVING expr]
+[ORDER BY expr_list] [WITH FILL] [FROM expr] [TO expr] [STEP expr]
+[LIMIT [offset_value, ]n BY columns]
+[LIMIT [n, ]m] [WITH TIES]
+[SETTINGS ...]
+[UNION  ...]
+[INTO OUTFILE filename [COMPRESSION type] ]
+[FORMAT format]
+```
+
+All clauses are optional, except for the required list of expressions immediately after `SELECT` which is covered in more detail [below](#select-clause).
+
+Specifics of each optional clause are covered in separate sections, which are listed in the same order as they are executed:
+
+-   [WITH clause](../../../sql-reference/statements/select/with.md)
+-   [SELECT clause](#select-clause)
+-   [DISTINCT clause](../../../sql-reference/statements/select/distinct.md)
+-   [FROM clause](../../../sql-reference/statements/select/from.md)
+-   [SAMPLE clause](../../../sql-reference/statements/select/sample.md)
+-   [JOIN clause](../../../sql-reference/statements/select/join.md)
+-   [PREWHERE clause](../../../sql-reference/statements/select/prewhere.md)
+-   [WHERE clause](../../../sql-reference/statements/select/where.md)
+-   [GROUP BY clause](../../../sql-reference/statements/select/group-by.md)
+-   [LIMIT BY clause](../../../sql-reference/statements/select/limit-by.md)
+-   [HAVING clause](../../../sql-reference/statements/select/having.md)
+-   [LIMIT clause](../../../sql-reference/statements/select/limit.md)
+-   [OFFSET clause](../../../sql-reference/statements/select/offset.md)
+-   [UNION clause](../../../sql-reference/statements/select/union.md)
+-   [INTERSECT clause](../../../sql-reference/statements/select/intersect.md)
+-   [EXCEPT clause](../../../sql-reference/statements/select/except.md)
+-   [INTO OUTFILE clause](../../../sql-reference/statements/select/into-outfile.md)
+-   [FORMAT clause](../../../sql-reference/statements/select/format.md)
+
+## SELECT Clause {#select-clause}
+
+[Expressions](../../../sql-reference/syntax.md#syntax-expressions) specified in the `SELECT` clause are calculated after all the operations in the clauses described above are finished. These expressions work as if they apply to separate rows in the result. If expressions in the `SELECT` clause contain aggregate functions, then ClickHouse processes aggregate functions and expressions used as their arguments during the [GROUP BY](../../../sql-reference/statements/select/group-by.md) aggregation.
+
+If you want to include all columns in the result, use the asterisk (`*`) symbol. For example, `SELECT * FROM ...`.
+
+
+### COLUMNS expression {#columns-expression}
+
+To match some columns in the result with a [re2](https://en.wikipedia.org/wiki/RE2_(software)) regular expression, you can use the `COLUMNS` expression.
+
+``` sql
+COLUMNS('regexp')
+```
+
+For example, consider the table:
+
+``` sql
+CREATE TABLE default.col_names (aa Int8, ab Int8, bc Int8) ENGINE = TinyLog
+```
+
+The following query selects data from all the columns containing the `a` symbol in their name.
+
+``` sql
+SELECT COLUMNS('a') FROM col_names
+```
+
+``` text
+┌─aa─┬─ab─┐
+│  1 │  1 │
+└────┴────┘
+```
+
+The selected columns are returned not in the alphabetical order.
+
+You can use multiple `COLUMNS` expressions in a query and apply functions to them.
+
+For example:
+
+``` sql
+SELECT COLUMNS('a'), COLUMNS('c'), toTypeName(COLUMNS('c')) FROM col_names
+```
+
+``` text
+┌─aa─┬─ab─┬─bc─┬─toTypeName(bc)─┐
+│  1 │  1 │  1 │ Int8           │
+└────┴────┴────┴────────────────┘
+```
+
+Each column returned by the `COLUMNS` expression is passed to the function as a separate argument. Also you can pass other arguments to the function if it supports them. Be careful when using functions. If a function does not support the number of arguments you have passed to it, ClickHouse throws an exception.
+
+For example:
+
+``` sql
+SELECT COLUMNS('a') + COLUMNS('c') FROM col_names
+```
+
+``` text
+Received exception from server (version 19.14.1):
+Code: 42. DB::Exception: Received from localhost:9000. DB::Exception: Number of arguments for function plus does not match: passed 3, should be 2.
+```
+
+In this example, `COLUMNS('a')` returns two columns: `aa` and `ab`. `COLUMNS('c')` returns the `bc` column. The `+` operator can’t apply to 3 arguments, so ClickHouse throws an exception with the relevant message.
+
+Columns that matched the `COLUMNS` expression can have different data types. If `COLUMNS` does not match any columns and is the only expression in `SELECT`, ClickHouse throws an exception.
+
+### Asterisk {#asterisk}
+
+You can put an asterisk in any part of a query instead of an expression. When the query is analyzed, the asterisk is expanded to a list of all table columns (excluding the `MATERIALIZED` and `ALIAS` columns). There are only a few cases when using an asterisk is justified:
+
+-   When creating a table dump.
+-   For tables containing just a few columns, such as system tables.
+-   For getting information about what columns are in a table. In this case, set `LIMIT 1`. But it is better to use the `DESC TABLE` query.
+-   When there is strong filtration on a small number of columns using `PREWHERE`.
+-   In subqueries (since columns that aren’t needed for the external query are excluded from subqueries).
+
+In all other cases, we do not recommend using the asterisk, since it only gives you the drawbacks of a columnar DBMS instead of the advantages. In other words using the asterisk is not recommended.
+
+### Extreme Values {#extreme-values}
+
+In addition to results, you can also get minimum and maximum values for the results columns. To do this, set the **extremes** setting to 1. Minimums and maximums are calculated for numeric types, dates, and dates with times. For other columns, the default values are output.
+
+An extra two rows are calculated – the minimums and maximums, respectively. These extra two rows are output in `JSON*`, `TabSeparated*`, and `Pretty*` [formats](../../../interfaces/formats.md), separate from the other rows. They are not output for other formats.
+
+In `JSON*` formats, the extreme values are output in a separate ‘extremes’ field. In `TabSeparated*` formats, the row comes after the main result, and after ‘totals’ if present. It is preceded by an empty row (after the other data). In `Pretty*` formats, the row is output as a separate table after the main result, and after `totals` if present.
+
+Extreme values are calculated for rows before `LIMIT`, but after `LIMIT BY`. However, when using `LIMIT offset, size`, the rows before `offset` are included in `extremes`. In stream requests, the result may also include a small number of rows that passed through `LIMIT`.
+
+### Notes {#notes}
+
+You can use synonyms (`AS` aliases) in any part of a query.
+
+The `GROUP BY`, `ORDER BY`, and `LIMIT BY` clauses can support positional arguments. To enable this, switch on the [enable_positional_arguments](../../../operations/settings/settings.md#enable-positional-arguments) setting. Then, for example, `ORDER BY 1,2` will be sorting rows in the table on the first and then the second column.
+
+## Implementation Details {#implementation-details}
+
+If the query omits the `DISTINCT`, `GROUP BY` and `ORDER BY` clauses and the `IN` and `JOIN` subqueries, the query will be completely stream processed, using O(1) amount of RAM. Otherwise, the query might consume a lot of RAM if the appropriate restrictions are not specified:
+
+-   `max_memory_usage`
+-   `max_rows_to_group_by`
+-   `max_rows_to_sort`
+-   `max_rows_in_distinct`
+-   `max_bytes_in_distinct`
+-   `max_rows_in_set`
+-   `max_bytes_in_set`
+-   `max_rows_in_join`
+-   `max_bytes_in_join`
+-   `max_bytes_before_external_sort`
+-   `max_bytes_before_external_group_by`
+
+For more information, see the section “Settings”. It is possible to use external sorting (saving temporary tables to a disk) and external aggregation.
+
+## SELECT modifiers {#select-modifiers}
+
+You can use the following modifiers in `SELECT` queries.
+
+### APPLY {#apply-modifier}
+
+Allows you to invoke some function for each row returned by an outer table expression of a query.
+
+**Syntax:**
+
+``` sql
+SELECT <expr> APPLY( <func> ) FROM [db.]table_name
+```
+
+**Example:**
+
+``` sql
+CREATE TABLE columns_transformers (i Int64, j Int16, k Int64) ENGINE = MergeTree ORDER by (i);
+INSERT INTO columns_transformers VALUES (100, 10, 324), (120, 8, 23);
+SELECT * APPLY(sum) FROM columns_transformers;
+```
+
+```
+┌─sum(i)─┬─sum(j)─┬─sum(k)─┐
+│    220 │     18 │    347 │
+└────────┴────────┴────────┘
+```
+
+### EXCEPT {#except-modifier}
+
+Specifies the names of one or more columns to exclude from the result. All matching column names are omitted from the output.
+
+**Syntax:**
+
+``` sql
+SELECT <expr> EXCEPT ( col_name1 [, col_name2, col_name3, ...] ) FROM [db.]table_name
+```
+
+**Example:**
+
+``` sql
+SELECT * EXCEPT (i) from columns_transformers;
+```
+
+```
+┌──j─┬───k─┐
+│ 10 │ 324 │
+│  8 │  23 │
+└────┴─────┘
+```
+
+### REPLACE {#replace-modifier}
+
+Specifies one or more [expression aliases](../../../sql-reference/syntax.md#syntax-expression_aliases). Each alias must match a column name from the `SELECT *` statement. In the output column list, the column that matches the alias is replaced by the expression in that `REPLACE`.
+
+This modifier does not change the names or order of columns. However, it can change the value and the value type.
+
+**Syntax:**
+
+``` sql
+SELECT <expr> REPLACE( <expr> AS col_name) from [db.]table_name
+```
+
+**Example:**
+
+``` sql
+SELECT * REPLACE(i + 1 AS i) from columns_transformers;
+```
+
+```
+┌───i─┬──j─┬───k─┐
+│ 101 │ 10 │ 324 │
+│ 121 │  8 │  23 │
+└─────┴────┴─────┘
+```
+
+### Modifier Combinations {#modifier-combinations}
+
+You can use each modifier separately or combine them.
+
+**Examples:**
+
+Using the same modifier multiple times.
+
+``` sql
+SELECT COLUMNS('[jk]') APPLY(toString) APPLY(length) APPLY(max) from columns_transformers;
+```
+
+```
+┌─max(length(toString(j)))─┬─max(length(toString(k)))─┐
+│                        2 │                        3 │
+└──────────────────────────┴──────────────────────────┘
+```
+
+Using multiple modifiers in a single query.
+
+``` sql
+SELECT * REPLACE(i + 1 AS i) EXCEPT (j) APPLY(sum) from columns_transformers;
+```
+
+```
+┌─sum(plus(i, 1))─┬─sum(k)─┐
+│             222 │    347 │
+└─────────────────┴────────┘
+```
+
+## SETTINGS in SELECT Query {#settings-in-select}
+
+You can specify the necessary settings right in the `SELECT` query. The setting value is applied only to this query and is reset to default or previous value after the query is executed.
+
+Other ways to make settings see [here](../../../operations/settings/index.md).
+
+**Example**
+
+``` sql
+SELECT * FROM some_table SETTINGS optimize_read_in_order=1, cast_keep_nullable=1;
+```
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/statements/select/)<!--hide-->
diff --git a/docs/en/reference/sql-reference/statements/select/intersect.md b/docs/en/reference/sql-reference/statements/select/intersect.md
new file mode 100644
index 00000000000..ef9868daebb
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/intersect.md
@@ -0,0 +1,73 @@
+---
+sidebar_label: INTERSECT
+---
+
+# INTERSECT Clause {#intersect-clause}
+
+The `INTERSECT` clause returns only those rows that result from both the first and the second queries. The queries must match the number of columns, order, and type. The result of `INTERSECT` can contain duplicate rows.
+
+Multiple `INTERSECT` statements are executes left to right if parenthesis are not specified. The `INTERSECT` operator has a higher priority than the `UNION` and `EXCEPT` clause.
+
+
+``` sql
+SELECT column1 [, column2 ]
+FROM table1
+[WHERE condition]
+
+INTERSECT
+
+SELECT column1 [, column2 ]
+FROM table2
+[WHERE condition]
+
+```
+The condition could be any expression based on your requirements.
+
+**Examples**
+
+Query:
+
+``` sql
+SELECT number FROM numbers(1,10) INTERSECT SELECT number FROM numbers(3,6);
+```
+
+Result:
+
+``` text
+┌─number─┐
+│      3 │
+│      4 │
+│      5 │
+│      6 │
+│      7 │
+│      8 │
+└────────┘
+```
+
+Query:
+
+``` sql
+CREATE TABLE t1(one String, two String, three String) ENGINE=Memory();
+CREATE TABLE t2(four String, five String, six String) ENGINE=Memory();
+
+INSERT INTO t1 VALUES ('q', 'm', 'b'), ('s', 'd', 'f'), ('l', 'p', 'o'), ('s', 'd', 'f'), ('s', 'd', 'f'), ('k', 't', 'd'), ('l', 'p', 'o');
+INSERT INTO t2 VALUES ('q', 'm', 'b'), ('b', 'd', 'k'), ('s', 'y', 't'), ('s', 'd', 'f'), ('m', 'f', 'o'), ('k', 'k', 'd');
+
+SELECT * FROM t1 INTERSECT SELECT * FROM t2;
+```
+
+Result:
+
+``` text
+┌─one─┬─two─┬─three─┐
+│ q   │ m   │ b     │
+│ s   │ d   │ f     │
+│ s   │ d   │ f     │
+│ s   │ d   │ f     │
+└─────┴─────┴───────┘
+```
+
+**See Also**
+
+-   [UNION](union.md#union-clause)
+-   [EXCEPT](except.md#except-clause)
diff --git a/docs/en/reference/sql-reference/statements/select/into-outfile.md b/docs/en/reference/sql-reference/statements/select/into-outfile.md
new file mode 100644
index 00000000000..b37285cb0cc
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/into-outfile.md
@@ -0,0 +1,38 @@
+---
+sidebar_label: INTO OUTFILE
+---
+
+# INTO OUTFILE Clause
+
+`INTO OUTFILE` clause redirects the result of a `SELECT` query to a file on the **client** side.
+
+Compressed files are supported. Compression type is detected by the extension of the file name (mode `'auto'` is used by default). Or it can be explicitly specified in a `COMPRESSION` clause.
+
+**Syntax**
+
+```sql
+SELECT <expr_list> INTO OUTFILE file_name [COMPRESSION type]
+```
+
+`file_name` and `type` are string literals. Supported compression types are: `'none'`, `'gzip'`, `'deflate'`, `'br'`, `'xz'`, `'zstd'`, `'lz4'`, `'bz2'`.
+
+## Implementation Details {#implementation-details}
+
+-   This functionality is available in the [command-line client](../../../interfaces/cli.md) and [clickhouse-local](../../../operations/utilities/clickhouse-local.md). Thus a query sent via [HTTP interface](../../../interfaces/http.md) will fail.
+-   The query will fail if a file with the same file name already exists.
+-   The default [output format](../../../interfaces/formats.md) is `TabSeparated` (like in the command-line client batch mode). Use [FORMAT](format.md) clause to change it.
+
+**Example**
+
+Execute the following query using [command-line client](../../../interfaces/cli.md):
+
+```bash
+clickhouse-client --query="SELECT 1,'ABC' INTO OUTFILE 'select.gz' FORMAT CSV;"
+zcat select.gz 
+```
+
+Result:
+
+```text
+1,"ABC"
+```
diff --git a/docs/en/reference/sql-reference/statements/select/join.md b/docs/en/reference/sql-reference/statements/select/join.md
new file mode 100644
index 00000000000..0cf58d0b90f
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/join.md
@@ -0,0 +1,338 @@
+---
+sidebar_label: JOIN
+---
+
+# JOIN Clause {#select-join}
+
+Join produces a new table by combining columns from one or multiple tables by using values common to each. It is a common operation in databases with SQL support, which corresponds to [relational algebra](https://en.wikipedia.org/wiki/Relational_algebra#Joins_and_join-like_operators) join. The special case of one table join is often referred to as “self-join”.
+
+**Syntax**
+
+``` sql
+SELECT <expr_list>
+FROM <left_table>
+[GLOBAL] [INNER|LEFT|RIGHT|FULL|CROSS] [OUTER|SEMI|ANTI|ANY|ASOF] JOIN <right_table>
+(ON <expr_list>)|(USING <column_list>) ...
+```
+
+Expressions from `ON` clause and columns from `USING` clause are called “join keys”. Unless otherwise stated, join produces a [Cartesian product](https://en.wikipedia.org/wiki/Cartesian_product) from rows with matching “join keys”, which might produce results with much more rows than the source tables.
+
+## Supported Types of JOIN {#select-join-types}
+
+All standard [SQL JOIN](https://en.wikipedia.org/wiki/Join_(SQL)) types are supported:
+
+-   `INNER JOIN`, only matching rows are returned.
+-   `LEFT OUTER JOIN`, non-matching rows from left table are returned in addition to matching rows.
+-   `RIGHT OUTER JOIN`, non-matching rows from right table are returned in addition to matching rows.
+-   `FULL OUTER JOIN`, non-matching rows from both tables are returned in addition to matching rows.
+-   `CROSS JOIN`, produces cartesian product of whole tables, “join keys” are **not** specified.
+
+`JOIN` without specified type implies `INNER`. Keyword `OUTER` can be safely omitted. Alternative syntax for `CROSS JOIN` is specifying multiple tables in [FROM clause](../../../sql-reference/statements/select/from.md) separated by commas.
+
+Additional join types available in ClickHouse:
+
+-   `LEFT SEMI JOIN` and `RIGHT SEMI JOIN`, a whitelist on “join keys”, without producing a cartesian product.
+-   `LEFT ANTI JOIN` and `RIGHT ANTI JOIN`, a blacklist on “join keys”, without producing a cartesian product.
+-   `LEFT ANY JOIN`, `RIGHT ANY JOIN` and `INNER ANY JOIN`, partially (for opposite side of `LEFT` and `RIGHT`) or completely (for `INNER` and `FULL`) disables the cartesian product for standard `JOIN` types.
+-   `ASOF JOIN` and `LEFT ASOF JOIN`, joining sequences with a non-exact match. `ASOF JOIN` usage is described below.
+
+:::note    
+When [join_algorithm](../../../operations/settings/settings.md#settings-join_algorithm) is set to `partial_merge`, `RIGHT JOIN` and `FULL JOIN` are supported only with `ALL` strictness (`SEMI`, `ANTI`, `ANY`, and `ASOF` are not supported).
+:::
+
+## Settings {#join-settings}
+
+The default join type can be overridden using [join_default_strictness](../../../operations/settings/settings.md#settings-join_default_strictness) setting.
+
+The behavior of ClickHouse server for `ANY JOIN` operations depends on the [any_join_distinct_right_table_keys](../../../operations/settings/settings.md#any_join_distinct_right_table_keys) setting.
+
+**See also**
+
+- [join_algorithm](../../../operations/settings/settings.md#settings-join_algorithm)
+- [join_any_take_last_row](../../../operations/settings/settings.md#settings-join_any_take_last_row)
+- [join_use_nulls](../../../operations/settings/settings.md#join_use_nulls)
+- [partial_merge_join_optimizations](../../../operations/settings/settings.md#partial_merge_join_optimizations)
+- [partial_merge_join_rows_in_right_blocks](../../../operations/settings/settings.md#partial_merge_join_rows_in_right_blocks)
+- [join_on_disk_max_files_to_merge](../../../operations/settings/settings.md#join_on_disk_max_files_to_merge)
+- [any_join_distinct_right_table_keys](../../../operations/settings/settings.md#any_join_distinct_right_table_keys)
+
+## ON Section Conditions {#on-section-conditions}
+
+An `ON` section can contain several conditions combined using the `AND` and `OR` operators. Conditions specifying join keys must refer both left and right tables and must use the equality operator. Other conditions may use other logical operators but they must refer either the left or the right table of a query.
+
+Rows are joined if the whole complex condition is met. If the conditions are not met, still rows may be included in the result depending on the `JOIN` type. Note that if the same conditions are placed in a `WHERE` section and they are not met, then rows are always filtered out from the result.
+
+The `OR` operator inside the `ON` clause works using the hash join algorithm — for each `OR` argument with join keys for `JOIN`, a separate hash table is created, so memory consumption and query execution time grow linearly with an increase in the number of expressions `OR` of the `ON` clause.
+
+:::note    
+If a condition refers columns from different tables, then only the equality operator (`=`) is supported so far.
+:::
+
+**Example**
+
+Consider `table_1` and `table_2`:
+
+```
+┌─Id─┬─name─┐     ┌─Id─┬─text───────────┬─scores─┐
+│  1 │ A    │     │  1 │ Text A         │     10 │
+│  2 │ B    │     │  1 │ Another text A │     12 │
+│  3 │ C    │     │  2 │ Text B         │     15 │
+└────┴──────┘     └────┴────────────────┴────────┘
+```
+
+Query with one join key condition and an additional condition for `table_2`:
+
+``` sql
+SELECT name, text FROM table_1 LEFT OUTER JOIN table_2 
+    ON table_1.Id = table_2.Id AND startsWith(table_2.text, 'Text');
+```
+
+Note that the result contains the row with the name `C` and the empty text column. It is included into the result because an `OUTER` type of a join is used.
+
+```
+┌─name─┬─text───┐
+│ A    │ Text A │
+│ B    │ Text B │
+│ C    │        │
+└──────┴────────┘
+```
+
+Query with `INNER` type of a join and multiple conditions:
+
+``` sql
+SELECT name, text, scores FROM table_1 INNER JOIN table_2 
+    ON table_1.Id = table_2.Id AND table_2.scores > 10 AND startsWith(table_2.text, 'Text');
+```
+
+Result:
+
+```
+┌─name─┬─text───┬─scores─┐
+│ B    │ Text B │     15 │
+└──────┴────────┴────────┘
+```
+Query with `INNER` type of a join and condition with `OR`:
+
+``` sql
+CREATE TABLE t1 (`a` Int64, `b` Int64) ENGINE = MergeTree() ORDER BY a;
+
+CREATE TABLE t2 (`key` Int32, `val` Int64) ENGINE = MergeTree() ORDER BY key;
+
+INSERT INTO t1 SELECT number as a, -a as b from numbers(5);
+
+INSERT INTO t2 SELECT if(number % 2 == 0, toInt64(number), -number) as key, number as val from numbers(5);
+
+SELECT a, b, val FROM t1 INNER JOIN t2 ON t1.a = t2.key OR t1.b = t2.key;
+```
+
+Result:
+
+```
+┌─a─┬──b─┬─val─┐
+│ 0 │  0 │   0 │
+│ 1 │ -1 │   1 │
+│ 2 │ -2 │   2 │
+│ 3 │ -3 │   3 │
+│ 4 │ -4 │   4 │
+└───┴────┴─────┘
+```
+
+Query with `INNER` type of a join and conditions with `OR` and `AND`:
+
+``` sql
+SELECT a, b, val FROM t1 INNER JOIN t2 ON t1.a = t2.key OR t1.b = t2.key AND t2.val > 3;
+```
+
+Result:
+
+```
+┌─a─┬──b─┬─val─┐
+│ 0 │  0 │   0 │
+│ 2 │ -2 │   2 │
+│ 4 │ -4 │   4 │
+└───┴────┴─────┘
+```
+## ASOF JOIN Usage {#asof-join-usage}
+
+`ASOF JOIN` is useful when you need to join records that have no exact match.
+
+Algorithm requires the special column in tables. This column:
+
+-   Must contain an ordered sequence.
+-   Can be one of the following types: [Int, UInt](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md), [Date](../../../sql-reference/data-types/date.md), [DateTime](../../../sql-reference/data-types/datetime.md), [Decimal](../../../sql-reference/data-types/decimal.md).
+-   Can’t be the only column in the `JOIN` clause.
+
+Syntax `ASOF JOIN ... ON`:
+
+``` sql
+SELECT expressions_list
+FROM table_1
+ASOF LEFT JOIN table_2
+ON equi_cond AND closest_match_cond
+```
+
+You can use any number of equality conditions and exactly one closest match condition. For example, `SELECT count() FROM table_1 ASOF LEFT JOIN table_2 ON table_1.a == table_2.b AND table_2.t <= table_1.t`.
+
+Conditions supported for the closest match: `>`, `>=`, `<`, `<=`.
+
+Syntax `ASOF JOIN ... USING`:
+
+``` sql
+SELECT expressions_list
+FROM table_1
+ASOF JOIN table_2
+USING (equi_column1, ... equi_columnN, asof_column)
+```
+
+`ASOF JOIN` uses `equi_columnX` for joining on equality and `asof_column` for joining on the closest match with the `table_1.asof_column >= table_2.asof_column` condition. The `asof_column` column is always the last one in the `USING` clause.
+
+For example, consider the following tables:
+
+         table_1                           table_2
+      event   | ev_time | user_id       event   | ev_time | user_id
+    ----------|---------|----------   ----------|---------|----------
+                  ...                               ...
+    event_1_1 |  12:00  |  42         event_2_1 |  11:59  |   42
+                  ...                 event_2_2 |  12:30  |   42
+    event_1_2 |  13:00  |  42         event_2_3 |  13:00  |   42
+                  ...                               ...
+
+`ASOF JOIN` can take the timestamp of a user event from `table_1` and find an event in `table_2` where the timestamp is closest to the timestamp of the event from `table_1` corresponding to the closest match condition. Equal timestamp values are the closest if available. Here, the `user_id` column can be used for joining on equality and the `ev_time` column can be used for joining on the closest match. In our example, `event_1_1` can be joined with `event_2_1` and `event_1_2` can be joined with `event_2_3`, but `event_2_2` can’t be joined.
+
+:::note    
+`ASOF` join is **not** supported in the [Join](../../../engines/table-engines/special/join.md) table engine.
+:::
+
+## Distributed JOIN {#global-join}
+
+There are two ways to execute join involving distributed tables:
+
+-   When using a normal `JOIN`, the query is sent to remote servers. Subqueries are run on each of them in order to make the right table, and the join is performed with this table. In other words, the right table is formed on each server separately.
+-   When using `GLOBAL ... JOIN`, first the requestor server runs a subquery to calculate the right table. This temporary table is passed to each remote server, and queries are run on them using the temporary data that was transmitted.
+
+Be careful when using `GLOBAL`. For more information, see the [Distributed subqueries](../../../sql-reference/operators/in.md#select-distributed-subqueries) section.
+
+## Implicit Type Conversion {#implicit-type-conversion}
+
+`INNER JOIN`, `LEFT JOIN`, `RIGHT JOIN`, and `FULL JOIN` queries support the implicit type conversion for "join keys". However the query can not be executed, if join keys from the left and the right tables cannot be converted to a single type (for example, there is no data type that can hold all values from both `UInt64` and `Int64`, or `String` and `Int32`).
+
+**Example**
+
+Consider the table `t_1`:
+```text
+┌─a─┬─b─┬─toTypeName(a)─┬─toTypeName(b)─┐
+│ 1 │ 1 │ UInt16        │ UInt8         │
+│ 2 │ 2 │ UInt16        │ UInt8         │
+└───┴───┴───────────────┴───────────────┘
+```
+and the table `t_2`:
+```text
+┌──a─┬────b─┬─toTypeName(a)─┬─toTypeName(b)───┐
+│ -1 │    1 │ Int16         │ Nullable(Int64) │
+│  1 │   -1 │ Int16         │ Nullable(Int64) │
+│  1 │    1 │ Int16         │ Nullable(Int64) │
+└────┴──────┴───────────────┴─────────────────┘
+```
+
+The query
+```sql
+SELECT a, b, toTypeName(a), toTypeName(b) FROM t_1 FULL JOIN t_2 USING (a, b);
+```
+returns the set:
+```text
+┌──a─┬────b─┬─toTypeName(a)─┬─toTypeName(b)───┐
+│  1 │    1 │ Int32         │ Nullable(Int64) │
+│  2 │    2 │ Int32         │ Nullable(Int64) │
+│ -1 │    1 │ Int32         │ Nullable(Int64) │
+│  1 │   -1 │ Int32         │ Nullable(Int64) │
+└────┴──────┴───────────────┴─────────────────┘
+```
+
+## Usage Recommendations {#usage-recommendations}
+
+### Processing of Empty or NULL Cells {#processing-of-empty-or-null-cells}
+
+While joining tables, the empty cells may appear. The setting [join_use_nulls](../../../operations/settings/settings.md#join_use_nulls) define how ClickHouse fills these cells.
+
+If the `JOIN` keys are [Nullable](../../../sql-reference/data-types/nullable.md) fields, the rows where at least one of the keys has the value [NULL](../../../sql-reference/syntax.md#null-literal) are not joined.
+
+### Syntax {#syntax}
+
+The columns specified in `USING` must have the same names in both subqueries, and the other columns must be named differently. You can use aliases to change the names of columns in subqueries.
+
+The `USING` clause specifies one or more columns to join, which establishes the equality of these columns. The list of columns is set without brackets. More complex join conditions are not supported.
+
+### Syntax Limitations {#syntax-limitations}
+
+For multiple `JOIN` clauses in a single `SELECT` query:
+
+-   Taking all the columns via `*` is available only if tables are joined, not subqueries.
+-   The `PREWHERE` clause is not available.
+
+For `ON`, `WHERE`, and `GROUP BY` clauses:
+
+-   Arbitrary expressions cannot be used in `ON`, `WHERE`, and `GROUP BY` clauses, but you can define an expression in a `SELECT` clause and then use it in these clauses via an alias.
+
+### Performance {#performance}
+
+When running a `JOIN`, there is no optimization of the order of execution in relation to other stages of the query. The join (a search in the right table) is run before filtering in `WHERE` and before aggregation.
+
+Each time a query is run with the same `JOIN`, the subquery is run again because the result is not cached. To avoid this, use the special [Join](../../../engines/table-engines/special/join.md) table engine, which is a prepared array for joining that is always in RAM.
+
+In some cases, it is more efficient to use [IN](../../../sql-reference/operators/in.md) instead of `JOIN`.
+
+If you need a `JOIN` for joining with dimension tables (these are relatively small tables that contain dimension properties, such as names for advertising campaigns), a `JOIN` might not be very convenient due to the fact that the right table is re-accessed for every query. For such cases, there is an “external dictionaries” feature that you should use instead of `JOIN`. For more information, see the [External dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts.md) section.
+
+### Memory Limitations {#memory-limitations}
+
+By default, ClickHouse uses the [hash join](https://en.wikipedia.org/wiki/Hash_join) algorithm. ClickHouse takes the right_table and creates a hash table for it in RAM. If `join_algorithm = 'auto'` is enabled, then after some threshold of memory consumption, ClickHouse falls back to [merge](https://en.wikipedia.org/wiki/Sort-merge_join) join algorithm. For `JOIN` algorithms description see the [join_algorithm](../../../operations/settings/settings.md#settings-join_algorithm) setting.
+
+If you need to restrict `JOIN` operation memory consumption use the following settings:
+
+-   [max_rows_in_join](../../../operations/settings/query-complexity.md#settings-max_rows_in_join) — Limits number of rows in the hash table.
+-   [max_bytes_in_join](../../../operations/settings/query-complexity.md#settings-max_bytes_in_join) — Limits size of the hash table.
+
+When any of these limits is reached, ClickHouse acts as the [join_overflow_mode](../../../operations/settings/query-complexity.md#settings-join_overflow_mode) setting instructs.
+
+## Examples {#examples}
+
+Example:
+
+``` sql
+SELECT
+    CounterID,
+    hits,
+    visits
+FROM
+(
+    SELECT
+        CounterID,
+        count() AS hits
+    FROM test.hits
+    GROUP BY CounterID
+) ANY LEFT JOIN
+(
+    SELECT
+        CounterID,
+        sum(Sign) AS visits
+    FROM test.visits
+    GROUP BY CounterID
+) USING CounterID
+ORDER BY hits DESC
+LIMIT 10
+```
+
+``` text
+┌─CounterID─┬───hits─┬─visits─┐
+│   1143050 │ 523264 │  13665 │
+│    731962 │ 475698 │ 102716 │
+│    722545 │ 337212 │ 108187 │
+│    722889 │ 252197 │  10547 │
+│   2237260 │ 196036 │   9522 │
+│  23057320 │ 147211 │   7689 │
+│    722818 │  90109 │  17847 │
+│     48221 │  85379 │   4652 │
+│  19762435 │  77807 │   7026 │
+│    722884 │  77492 │  11056 │
+└───────────┴────────┴────────┘
+```
diff --git a/docs/en/reference/sql-reference/statements/select/limit-by.md b/docs/en/reference/sql-reference/statements/select/limit-by.md
new file mode 100644
index 00000000000..913b7b40338
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/limit-by.md
@@ -0,0 +1,74 @@
+---
+sidebar_label: LIMIT BY
+---
+
+# LIMIT BY Clause {#limit-by-clause}
+
+A query with the `LIMIT n BY expressions` clause selects the first `n` rows for each distinct value of `expressions`. The key for `LIMIT BY` can contain any number of [expressions](../../../sql-reference/syntax.md#syntax-expressions).
+
+ClickHouse supports the following syntax variants:
+
+-   `LIMIT [offset_value, ]n BY expressions`
+-   `LIMIT n OFFSET offset_value BY expressions`
+
+During query processing, ClickHouse selects data ordered by sorting key. The sorting key is set explicitly using an [ORDER BY](order-by.md#select-order-by) clause or implicitly as a property of the table engine (row order is only guaranteed when using [ORDER BY](order-by.md#select-order-by), otherwise the row blocks will not be ordered due to multi-threading). Then ClickHouse applies `LIMIT n BY expressions` and returns the first `n` rows for each distinct combination of `expressions`. If `OFFSET` is specified, then for each data block that belongs to a distinct combination of `expressions`, ClickHouse skips `offset_value` number of rows from the beginning of the block and returns a maximum of `n` rows as a result. If `offset_value` is bigger than the number of rows in the data block, ClickHouse returns zero rows from the block.
+
+:::note    
+`LIMIT BY` is not related to [LIMIT](../../../sql-reference/statements/select/limit.md). They can both be used in the same query.
+:::
+
+If you want to use column numbers instead of column names in the `LIMIT BY` clause, enable the setting [enable_positional_arguments](../../../operations/settings/settings.md#enable-positional-arguments).	
+	
+
+## Examples {#examples}
+
+Sample table:
+
+``` sql
+CREATE TABLE limit_by(id Int, val Int) ENGINE = Memory;
+INSERT INTO limit_by VALUES (1, 10), (1, 11), (1, 12), (2, 20), (2, 21);
+```
+
+Queries:
+
+``` sql
+SELECT * FROM limit_by ORDER BY id, val LIMIT 2 BY id
+```
+
+``` text
+┌─id─┬─val─┐
+│  1 │  10 │
+│  1 │  11 │
+│  2 │  20 │
+│  2 │  21 │
+└────┴─────┘
+```
+
+``` sql
+SELECT * FROM limit_by ORDER BY id, val LIMIT 1, 2 BY id
+```
+
+``` text
+┌─id─┬─val─┐
+│  1 │  11 │
+│  1 │  12 │
+│  2 │  21 │
+└────┴─────┘
+```
+
+The `SELECT * FROM limit_by ORDER BY id, val LIMIT 2 OFFSET 1 BY id` query returns the same result.
+
+The following query returns the top 5 referrers for each `domain, device_type` pair with a maximum of 100 rows in total (`LIMIT n BY + LIMIT`).
+
+``` sql
+SELECT
+    domainWithoutWWW(URL) AS domain,
+    domainWithoutWWW(REFERRER_URL) AS referrer,
+    device_type,
+    count() cnt
+FROM hits
+GROUP BY domain, referrer, device_type
+ORDER BY cnt DESC
+LIMIT 5 BY domain, device_type
+LIMIT 100
+```
diff --git a/docs/en/reference/sql-reference/statements/select/limit.md b/docs/en/reference/sql-reference/statements/select/limit.md
new file mode 100644
index 00000000000..6b1c90041fe
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/limit.md
@@ -0,0 +1,66 @@
+---
+sidebar_label: LIMIT
+---
+
+# LIMIT Clause {#limit-clause}
+
+`LIMIT m` allows to select the first `m` rows from the result.
+
+`LIMIT n, m` allows to select the `m` rows from the result after skipping the first `n` rows. The `LIMIT m OFFSET n` syntax is equivalent.
+
+`n` and `m` must be non-negative integers.
+
+If there is no [ORDER BY](../../../sql-reference/statements/select/order-by.md) clause that explicitly sorts results, the choice of rows for the result may be arbitrary and non-deterministic.
+
+:::note    
+The number of rows in the result set can also depend on the [limit](../../../operations/settings/settings.md#limit) setting.
+:::
+
+## LIMIT … WITH TIES Modifier {#limit-with-ties}
+
+When you set `WITH TIES` modifier for `LIMIT n[,m]` and specify `ORDER BY expr_list`, you will get in result first `n` or `n,m` rows and all rows with same `ORDER BY` fields values equal to row at position `n` for `LIMIT n` and `m` for `LIMIT n,m`.
+
+This modifier also can be combined with [ORDER BY … WITH FILL modifier](../../../sql-reference/statements/select/order-by.md#orderby-with-fill).
+
+For example, the following query
+
+``` sql
+SELECT * FROM (
+    SELECT number%50 AS n FROM numbers(100)
+) ORDER BY n LIMIT 0,5
+```
+
+returns
+
+``` text
+┌─n─┐
+│ 0 │
+│ 0 │
+│ 1 │
+│ 1 │
+│ 2 │
+└───┘
+```
+
+but after apply `WITH TIES` modifier
+
+``` sql
+SELECT * FROM (
+    SELECT number%50 AS n FROM numbers(100)
+) ORDER BY n LIMIT 0,5 WITH TIES
+```
+
+it returns another rows set
+
+``` text
+┌─n─┐
+│ 0 │
+│ 0 │
+│ 1 │
+│ 1 │
+│ 2 │
+│ 2 │
+└───┘
+```
+
+cause row number 6 have same value “2” for field `n` as row number 5
diff --git a/docs/en/reference/sql-reference/statements/select/offset.md b/docs/en/reference/sql-reference/statements/select/offset.md
new file mode 100644
index 00000000000..e120845dbc6
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/offset.md
@@ -0,0 +1,88 @@
+---
+sidebar_label: OFFSET
+---
+
+# OFFSET FETCH Clause {#offset-fetch}
+
+`OFFSET` and `FETCH` allow you to retrieve data by portions. They specify a row block which you want to get by a single query.
+
+``` sql
+OFFSET offset_row_count {ROW | ROWS}] [FETCH {FIRST | NEXT} fetch_row_count {ROW | ROWS} {ONLY | WITH TIES}]
+```
+
+The `offset_row_count` or `fetch_row_count` value can be a number or a literal constant. You can omit `fetch_row_count`; by default, it equals to 1.
+
+`OFFSET` specifies the number of rows to skip before starting to return rows from the query result set.
+
+The `FETCH` specifies the maximum number of rows that can be in the result of a query.
+
+The `ONLY` option is used to return rows that immediately follow the rows omitted by the `OFFSET`. In this case the `FETCH` is an alternative to the [LIMIT](../../../sql-reference/statements/select/limit.md) clause. For example, the following query
+
+``` sql
+SELECT * FROM test_fetch ORDER BY a OFFSET 1 ROW FETCH FIRST 3 ROWS ONLY;
+```
+
+is identical to the query
+
+``` sql
+SELECT * FROM test_fetch ORDER BY a LIMIT 3 OFFSET 1;
+```
+
+The `WITH TIES` option is used to return any additional rows that tie for the last place in the result set according to the `ORDER BY` clause. For example, if `fetch_row_count` is set to 5 but two additional rows match the values of the `ORDER BY` columns in the fifth row, the result set will contain seven rows.
+
+:::note    
+According to the standard, the `OFFSET` clause must come before the `FETCH` clause if both are present.
+:::
+
+:::note    
+The real offset can also depend on the [offset](../../../operations/settings/settings.md#offset) setting.
+:::
+
+## Examples {#examples}
+
+Input table:
+
+``` text
+┌─a─┬─b─┐
+│ 1 │ 1 │
+│ 2 │ 1 │
+│ 3 │ 4 │
+│ 1 │ 3 │
+│ 5 │ 4 │
+│ 0 │ 6 │
+│ 5 │ 7 │
+└───┴───┘
+```
+
+Usage of the `ONLY` option:
+
+``` sql
+SELECT * FROM test_fetch ORDER BY a OFFSET 3 ROW FETCH FIRST 3 ROWS ONLY;
+```
+
+Result:
+
+``` text
+┌─a─┬─b─┐
+│ 2 │ 1 │
+│ 3 │ 4 │
+│ 5 │ 4 │
+└───┴───┘
+```
+
+Usage of the `WITH TIES` option:
+
+``` sql
+SELECT * FROM test_fetch ORDER BY a OFFSET 3 ROW FETCH FIRST 3 ROWS WITH TIES;
+```
+
+Result:
+
+``` text
+┌─a─┬─b─┐
+│ 2 │ 1 │
+│ 3 │ 4 │
+│ 5 │ 4 │
+│ 5 │ 7 │
+└───┴───┘
+```
diff --git a/docs/en/reference/sql-reference/statements/select/order-by.md b/docs/en/reference/sql-reference/statements/select/order-by.md
new file mode 100644
index 00000000000..46e483dddf4
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/order-by.md
@@ -0,0 +1,486 @@
+---
+sidebar_label: ORDER BY
+---
+
+# ORDER BY Clause {#select-order-by}
+
+The `ORDER BY` clause contains a list of expressions, which can each be attributed with `DESC` (descending) or `ASC` (ascending) modifier which determine the sorting direction. If the direction is not specified, `ASC` is assumed, so it’s usually omitted. The sorting direction applies to a single expression, not to the entire list. Example: `ORDER BY Visits DESC, SearchPhrase`.
+
+If you want to sort by column numbers instead of column names, enable the setting [enable_positional_arguments](../../../operations/settings/settings.md#enable-positional-arguments).
+
+Rows that have identical values for the list of sorting expressions are output in an arbitrary order, which can also be non-deterministic (different each time).
+If the ORDER BY clause is omitted, the order of the rows is also undefined, and may be non-deterministic as well.
+
+## Sorting of Special Values {#sorting-of-special-values}
+
+There are two approaches to `NaN` and `NULL` sorting order:
+
+-   By default or with the `NULLS LAST` modifier: first the values, then `NaN`, then `NULL`.
+-   With the `NULLS FIRST` modifier: first `NULL`, then `NaN`, then other values.
+
+### Example {#example}
+
+For the table
+
+``` text
+┌─x─┬────y─┐
+│ 1 │ ᴺᵁᴸᴸ │
+│ 2 │    2 │
+│ 1 │  nan │
+│ 2 │    2 │
+│ 3 │    4 │
+│ 5 │    6 │
+│ 6 │  nan │
+│ 7 │ ᴺᵁᴸᴸ │
+│ 6 │    7 │
+│ 8 │    9 │
+└───┴──────┘
+```
+
+Run the query `SELECT * FROM t_null_nan ORDER BY y NULLS FIRST` to get:
+
+``` text
+┌─x─┬────y─┐
+│ 1 │ ᴺᵁᴸᴸ │
+│ 7 │ ᴺᵁᴸᴸ │
+│ 1 │  nan │
+│ 6 │  nan │
+│ 2 │    2 │
+│ 2 │    2 │
+│ 3 │    4 │
+│ 5 │    6 │
+│ 6 │    7 │
+│ 8 │    9 │
+└───┴──────┘
+```
+
+When floating point numbers are sorted, NaNs are separate from the other values. Regardless of the sorting order, NaNs come at the end. In other words, for ascending sorting they are placed as if they are larger than all the other numbers, while for descending sorting they are placed as if they are smaller than the rest.
+
+## Collation Support {#collation-support}
+
+For sorting by [String](../../../sql-reference/data-types/string.md) values, you can specify collation (comparison). Example: `ORDER BY SearchPhrase COLLATE 'tr'` - for sorting by keyword in ascending order, using the Turkish alphabet, case insensitive, assuming that strings are UTF-8 encoded. `COLLATE` can be specified or not for each expression in ORDER BY independently. If `ASC` or `DESC` is specified, `COLLATE` is specified after it. When using `COLLATE`, sorting is always case-insensitive.
+
+Collate is supported in [LowCardinality](../../../sql-reference/data-types/lowcardinality.md), [Nullable](../../../sql-reference/data-types/nullable.md), [Array](../../../sql-reference/data-types/array.md) and [Tuple](../../../sql-reference/data-types/tuple.md).
+
+We only recommend using `COLLATE` for final sorting of a small number of rows, since sorting with `COLLATE` is less efficient than normal sorting by bytes.
+
+## Collation Examples {#collation-examples}
+
+Example only with [String](../../../sql-reference/data-types/string.md) values:
+
+Input table:
+
+``` text
+┌─x─┬─s────┐
+│ 1 │ bca  │
+│ 2 │ ABC  │
+│ 3 │ 123a │
+│ 4 │ abc  │
+│ 5 │ BCA  │
+└───┴──────┘
+```
+
+Query:
+
+```sql
+SELECT * FROM collate_test ORDER BY s ASC COLLATE 'en';
+```
+
+Result:
+
+``` text
+┌─x─┬─s────┐
+│ 3 │ 123a │
+│ 4 │ abc  │
+│ 2 │ ABC  │
+│ 1 │ bca  │
+│ 5 │ BCA  │
+└───┴──────┘
+```
+
+Example with [Nullable](../../../sql-reference/data-types/nullable.md):
+
+Input table:
+
+``` text
+┌─x─┬─s────┐
+│ 1 │ bca  │
+│ 2 │ ᴺᵁᴸᴸ │
+│ 3 │ ABC  │
+│ 4 │ 123a │
+│ 5 │ abc  │
+│ 6 │ ᴺᵁᴸᴸ │
+│ 7 │ BCA  │
+└───┴──────┘
+```
+
+Query:
+
+```sql
+SELECT * FROM collate_test ORDER BY s ASC COLLATE 'en';
+```
+
+Result:
+
+``` text
+┌─x─┬─s────┐
+│ 4 │ 123a │
+│ 5 │ abc  │
+│ 3 │ ABC  │
+│ 1 │ bca  │
+│ 7 │ BCA  │
+│ 6 │ ᴺᵁᴸᴸ │
+│ 2 │ ᴺᵁᴸᴸ │
+└───┴──────┘
+```
+
+Example with [Array](../../../sql-reference/data-types/array.md):
+
+Input table:
+
+``` text
+┌─x─┬─s─────────────┐
+│ 1 │ ['Z']         │
+│ 2 │ ['z']         │
+│ 3 │ ['a']         │
+│ 4 │ ['A']         │
+│ 5 │ ['z','a']     │
+│ 6 │ ['z','a','a'] │
+│ 7 │ ['']          │
+└───┴───────────────┘
+```
+
+Query:
+
+```sql
+SELECT * FROM collate_test ORDER BY s ASC COLLATE 'en';
+```
+
+Result:
+
+``` text
+┌─x─┬─s─────────────┐
+│ 7 │ ['']          │
+│ 3 │ ['a']         │
+│ 4 │ ['A']         │
+│ 2 │ ['z']         │
+│ 5 │ ['z','a']     │
+│ 6 │ ['z','a','a'] │
+│ 1 │ ['Z']         │
+└───┴───────────────┘
+```
+
+Example with [LowCardinality](../../../sql-reference/data-types/lowcardinality.md) string:
+
+Input table:
+
+```text
+┌─x─┬─s───┐
+│ 1 │ Z   │
+│ 2 │ z   │
+│ 3 │ a   │
+│ 4 │ A   │
+│ 5 │ za  │
+│ 6 │ zaa │
+│ 7 │     │
+└───┴─────┘
+```
+
+Query:
+
+```sql
+SELECT * FROM collate_test ORDER BY s ASC COLLATE 'en';
+```
+
+Result:
+
+```text
+┌─x─┬─s───┐
+│ 7 │     │
+│ 3 │ a   │
+│ 4 │ A   │
+│ 2 │ z   │
+│ 1 │ Z   │
+│ 5 │ za  │
+│ 6 │ zaa │
+└───┴─────┘
+```
+
+Example with [Tuple](../../../sql-reference/data-types/tuple.md):
+
+```text
+┌─x─┬─s───────┐
+│ 1 │ (1,'Z') │
+│ 2 │ (1,'z') │
+│ 3 │ (1,'a') │
+│ 4 │ (2,'z') │
+│ 5 │ (1,'A') │
+│ 6 │ (2,'Z') │
+│ 7 │ (2,'A') │
+└───┴─────────┘
+```
+
+Query:
+
+```sql
+SELECT * FROM collate_test ORDER BY s ASC COLLATE 'en';
+```
+
+Result:
+
+```text
+┌─x─┬─s───────┐
+│ 3 │ (1,'a') │
+│ 5 │ (1,'A') │
+│ 2 │ (1,'z') │
+│ 1 │ (1,'Z') │
+│ 7 │ (2,'A') │
+│ 4 │ (2,'z') │
+│ 6 │ (2,'Z') │
+└───┴─────────┘
+```
+
+## Implementation Details {#implementation-details}
+
+Less RAM is used if a small enough [LIMIT](../../../sql-reference/statements/select/limit.md) is specified in addition to `ORDER BY`. Otherwise, the amount of memory spent is proportional to the volume of data for sorting. For distributed query processing, if [GROUP BY](../../../sql-reference/statements/select/group-by.md) is omitted, sorting is partially done on remote servers, and the results are merged on the requestor server. This means that for distributed sorting, the volume of data to sort can be greater than the amount of memory on a single server.
+
+If there is not enough RAM, it is possible to perform sorting in external memory (creating temporary files on a disk). Use the setting `max_bytes_before_external_sort` for this purpose. If it is set to 0 (the default), external sorting is disabled. If it is enabled, when the volume of data to sort reaches the specified number of bytes, the collected data is sorted and dumped into a temporary file. After all data is read, all the sorted files are merged and the results are output. Files are written to the `/var/lib/clickhouse/tmp/` directory in the config (by default, but you can use the `tmp_path` parameter to change this setting).
+
+Running a query may use more memory than `max_bytes_before_external_sort`. For this reason, this setting must have a value significantly smaller than `max_memory_usage`. As an example, if your server has 128 GB of RAM and you need to run a single query, set `max_memory_usage` to 100 GB, and `max_bytes_before_external_sort` to 80 GB.
+
+External sorting works much less effectively than sorting in RAM.
+
+## Optimization of Data Reading {#optimize_read_in_order}
+
+ If `ORDER BY` expression has a prefix that coincides with the table sorting key, you can optimize the query by using the [optimize_read_in_order](../../../operations/settings/settings.md#optimize_read_in_order) setting.
+
+ When the `optimize_read_in_order` setting is enabled, the ClickHouse server uses the table index and reads the data in order of the `ORDER BY` key. This allows to avoid reading all data in case of specified [LIMIT](../../../sql-reference/statements/select/limit.md). So queries on big data with small limit are processed faster.
+
+Optimization works with both `ASC` and `DESC` and does not work together with [GROUP BY](../../../sql-reference/statements/select/group-by.md) clause and [FINAL](../../../sql-reference/statements/select/from.md#select-from-final) modifier.
+
+When the `optimize_read_in_order` setting is disabled, the ClickHouse server does not use the table index while processing `SELECT` queries.
+
+Consider disabling `optimize_read_in_order` manually, when running queries that have `ORDER BY` clause, large `LIMIT` and [WHERE](../../../sql-reference/statements/select/where.md) condition that requires to read huge amount of records before queried data is found.
+
+Optimization is supported in the following table engines:
+
+- [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md)
+- [Merge](../../../engines/table-engines/special/merge.md), [Buffer](../../../engines/table-engines/special/buffer.md), and [MaterializedView](../../../engines/table-engines/special/materializedview.md) table engines over `MergeTree`-engine tables
+
+In `MaterializedView`-engine tables the optimization works with views like `SELECT ... FROM merge_tree_table ORDER BY pk`. But it is not supported in the queries like `SELECT ... FROM view ORDER BY pk` if the view query does not have the `ORDER BY` clause.
+
+## ORDER BY Expr WITH FILL Modifier {#orderby-with-fill}
+
+This modifier also can be combined with [LIMIT … WITH TIES modifier](../../../sql-reference/statements/select/limit.md#limit-with-ties).
+
+`WITH FILL` modifier can be set after `ORDER BY expr` with optional `FROM expr`, `TO expr` and `STEP expr` parameters.
+All missed values of `expr` column will be filled sequentially and other columns will be filled as defaults.
+
+To fill multiple columns, add `WITH FILL` modifier with optional parameters after each field name in `ORDER BY` section.
+
+``` sql
+ORDER BY expr [WITH FILL] [FROM const_expr] [TO const_expr] [STEP const_numeric_expr], ... exprN [WITH FILL] [FROM expr] [TO expr] [STEP numeric_expr]
+```
+
+`WITH FILL` can be applied for fields with Numeric (all kinds of float, decimal, int) or Date/DateTime types. When applied for `String` fields, missed values are filled with empty strings.
+When `FROM const_expr` not defined sequence of filling use minimal `expr` field value from `ORDER BY`.
+When `TO const_expr` not defined sequence of filling use maximum `expr` field value from `ORDER BY`.
+When `STEP const_numeric_expr` defined then `const_numeric_expr` interprets `as is` for numeric types, as `days` for Date type, as `seconds` for DateTime type. It also supports [INTERVAL](https://clickhouse.com/docs/en/sql-reference/data-types/special-data-types/interval/) data type representing time and date intervals.
+When `STEP const_numeric_expr` omitted then sequence of filling use `1.0` for numeric type, `1 day` for Date type and `1 second` for DateTime type.
+
+Example of a query without `WITH FILL`:
+
+``` sql
+SELECT n, source FROM (
+   SELECT toFloat32(number % 10) AS n, 'original' AS source
+   FROM numbers(10) WHERE number % 3 = 1
+) ORDER BY n;
+```
+
+Result:
+
+``` text
+┌─n─┬─source───┐
+│ 1 │ original │
+│ 4 │ original │
+│ 7 │ original │
+└───┴──────────┘
+```
+
+Same query after applying `WITH FILL` modifier:
+
+``` sql
+SELECT n, source FROM (
+   SELECT toFloat32(number % 10) AS n, 'original' AS source
+   FROM numbers(10) WHERE number % 3 = 1
+) ORDER BY n WITH FILL FROM 0 TO 5.51 STEP 0.5;
+```
+
+Result:
+
+``` text
+┌───n─┬─source───┐
+│   0 │          │
+│ 0.5 │          │
+│   1 │ original │
+│ 1.5 │          │
+│   2 │          │
+│ 2.5 │          │
+│   3 │          │
+│ 3.5 │          │
+│   4 │ original │
+│ 4.5 │          │
+│   5 │          │
+│ 5.5 │          │
+│   7 │ original │
+└─────┴──────────┘
+```
+
+For the case with multiple fields `ORDER BY field2 WITH FILL, field1 WITH FILL` order of filling will follow the order of fields in the `ORDER BY` clause.
+
+Example:
+
+``` sql
+SELECT
+    toDate((number * 10) * 86400) AS d1,
+    toDate(number * 86400) AS d2,
+    'original' AS source
+FROM numbers(10)
+WHERE (number % 3) = 1
+ORDER BY
+    d2 WITH FILL,
+    d1 WITH FILL STEP 5;
+```
+
+Result:
+
+``` text
+┌───d1───────┬───d2───────┬─source───┐
+│ 1970-01-11 │ 1970-01-02 │ original │
+│ 1970-01-01 │ 1970-01-03 │          │
+│ 1970-01-01 │ 1970-01-04 │          │
+│ 1970-02-10 │ 1970-01-05 │ original │
+│ 1970-01-01 │ 1970-01-06 │          │
+│ 1970-01-01 │ 1970-01-07 │          │
+│ 1970-03-12 │ 1970-01-08 │ original │
+└────────────┴────────────┴──────────┘
+```
+
+Field `d1` does not fill in and use the default value cause we do not have repeated values for `d2` value, and the sequence for `d1` can’t be properly calculated.
+
+The following query with the changed field in `ORDER BY`:
+
+``` sql
+SELECT
+    toDate((number * 10) * 86400) AS d1,
+    toDate(number * 86400) AS d2,
+    'original' AS source
+FROM numbers(10)
+WHERE (number % 3) = 1
+ORDER BY
+    d1 WITH FILL STEP 5,
+    d2 WITH FILL;
+```
+
+Result:
+
+``` text
+┌───d1───────┬───d2───────┬─source───┐
+│ 1970-01-11 │ 1970-01-02 │ original │
+│ 1970-01-16 │ 1970-01-01 │          │
+│ 1970-01-21 │ 1970-01-01 │          │
+│ 1970-01-26 │ 1970-01-01 │          │
+│ 1970-01-31 │ 1970-01-01 │          │
+│ 1970-02-05 │ 1970-01-01 │          │
+│ 1970-02-10 │ 1970-01-05 │ original │
+│ 1970-02-15 │ 1970-01-01 │          │
+│ 1970-02-20 │ 1970-01-01 │          │
+│ 1970-02-25 │ 1970-01-01 │          │
+│ 1970-03-02 │ 1970-01-01 │          │
+│ 1970-03-07 │ 1970-01-01 │          │
+│ 1970-03-12 │ 1970-01-08 │ original │
+└────────────┴────────────┴──────────┘
+```
+
+The following query uses the `INTERVAL` data type of 1 day for each data filled on column `d1`:
+
+``` sql
+SELECT
+    toDate((number * 10) * 86400) AS d1,
+    toDate(number * 86400) AS d2,
+    'original' AS source
+FROM numbers(10)
+WHERE (number % 3) = 1
+ORDER BY
+    d1 WITH FILL STEP INTERVAL 1 DAY,
+    d2 WITH FILL;
+```
+
+Result:
+```
+┌─────────d1─┬─────────d2─┬─source───┐
+│ 1970-01-11 │ 1970-01-02 │ original │
+│ 1970-01-12 │ 1970-01-01 │          │
+│ 1970-01-13 │ 1970-01-01 │          │
+│ 1970-01-14 │ 1970-01-01 │          │
+│ 1970-01-15 │ 1970-01-01 │          │
+│ 1970-01-16 │ 1970-01-01 │          │
+│ 1970-01-17 │ 1970-01-01 │          │
+│ 1970-01-18 │ 1970-01-01 │          │
+│ 1970-01-19 │ 1970-01-01 │          │
+│ 1970-01-20 │ 1970-01-01 │          │
+│ 1970-01-21 │ 1970-01-01 │          │
+│ 1970-01-22 │ 1970-01-01 │          │
+│ 1970-01-23 │ 1970-01-01 │          │
+│ 1970-01-24 │ 1970-01-01 │          │
+│ 1970-01-25 │ 1970-01-01 │          │
+│ 1970-01-26 │ 1970-01-01 │          │
+│ 1970-01-27 │ 1970-01-01 │          │
+│ 1970-01-28 │ 1970-01-01 │          │
+│ 1970-01-29 │ 1970-01-01 │          │
+│ 1970-01-30 │ 1970-01-01 │          │
+│ 1970-01-31 │ 1970-01-01 │          │
+│ 1970-02-01 │ 1970-01-01 │          │
+│ 1970-02-02 │ 1970-01-01 │          │
+│ 1970-02-03 │ 1970-01-01 │          │
+│ 1970-02-04 │ 1970-01-01 │          │
+│ 1970-02-05 │ 1970-01-01 │          │
+│ 1970-02-06 │ 1970-01-01 │          │
+│ 1970-02-07 │ 1970-01-01 │          │
+│ 1970-02-08 │ 1970-01-01 │          │
+│ 1970-02-09 │ 1970-01-01 │          │
+│ 1970-02-10 │ 1970-01-05 │ original │
+│ 1970-02-11 │ 1970-01-01 │          │
+│ 1970-02-12 │ 1970-01-01 │          │
+│ 1970-02-13 │ 1970-01-01 │          │
+│ 1970-02-14 │ 1970-01-01 │          │
+│ 1970-02-15 │ 1970-01-01 │          │
+│ 1970-02-16 │ 1970-01-01 │          │
+│ 1970-02-17 │ 1970-01-01 │          │
+│ 1970-02-18 │ 1970-01-01 │          │
+│ 1970-02-19 │ 1970-01-01 │          │
+│ 1970-02-20 │ 1970-01-01 │          │
+│ 1970-02-21 │ 1970-01-01 │          │
+│ 1970-02-22 │ 1970-01-01 │          │
+│ 1970-02-23 │ 1970-01-01 │          │
+│ 1970-02-24 │ 1970-01-01 │          │
+│ 1970-02-25 │ 1970-01-01 │          │
+│ 1970-02-26 │ 1970-01-01 │          │
+│ 1970-02-27 │ 1970-01-01 │          │
+│ 1970-02-28 │ 1970-01-01 │          │
+│ 1970-03-01 │ 1970-01-01 │          │
+│ 1970-03-02 │ 1970-01-01 │          │
+│ 1970-03-03 │ 1970-01-01 │          │
+│ 1970-03-04 │ 1970-01-01 │          │
+│ 1970-03-05 │ 1970-01-01 │          │
+│ 1970-03-06 │ 1970-01-01 │          │
+│ 1970-03-07 │ 1970-01-01 │          │
+│ 1970-03-08 │ 1970-01-01 │          │
+│ 1970-03-09 │ 1970-01-01 │          │
+│ 1970-03-10 │ 1970-01-01 │          │
+│ 1970-03-11 │ 1970-01-01 │          │
+│ 1970-03-12 │ 1970-01-08 │ original │
+└────────────┴────────────┴──────────┘
+```
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/statements/select/order-by/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/statements/select/prewhere.md b/docs/en/reference/sql-reference/statements/select/prewhere.md
new file mode 100644
index 00000000000..c3aa2e14384
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/prewhere.md
@@ -0,0 +1,27 @@
+---
+sidebar_label: PREWHERE
+---
+
+# PREWHERE Clause {#prewhere-clause}
+
+Prewhere is an optimization to apply filtering more efficiently. It is enabled by default even if `PREWHERE` clause is not specified explicitly. It works by automatically moving part of [WHERE](../../../sql-reference/statements/select/where.md) condition to prewhere stage. The role of `PREWHERE` clause is only to control this optimization if you think that you know how to do it better than it happens by default.
+
+With prewhere optimization, at first only the columns necessary for executing prewhere expression are read. Then the other columns are read that are needed for running the rest of the query, but only those blocks where the prewhere expression is `true` at least for some rows. If there are a lot of blocks where prewhere expression is `false` for all rows and prewhere needs less columns than other parts of query, this often allows to read a lot less data from disk for query execution.
+
+## Controlling Prewhere Manually {#controlling-prewhere-manually}
+
+The clause has the same meaning as the `WHERE` clause. The difference is in which data is read from the table. When manually controlling `PREWHERE` for filtration conditions that are used by a minority of the columns in the query, but that provide strong data filtration. This reduces the volume of data to read.
+
+A query may simultaneously specify `PREWHERE` and `WHERE`. In this case, `PREWHERE` precedes `WHERE`.
+
+If the [optimize_move_to_prewhere](../../../operations/settings/settings.md#optimize_move_to_prewhere) setting is set to 0, heuristics to automatically move parts of expressions from `WHERE` to `PREWHERE` are disabled.
+
+If query has [FINAL](from.md#select-from-final) modifier, the `PREWHERE` optimization is not always correct. It is enabled only if both settings [optimize_move_to_prewhere](../../../operations/settings/settings.md#optimize_move_to_prewhere) and [optimize_move_to_prewhere_if_final](../../../operations/settings/settings.md#optimize_move_to_prewhere_if_final) are turned on.
+
+:::note    
+The `PREWHERE` section is executed before `FINAL`, so the results of `FROM ... FINAL` queries may be skewed when using `PREWHERE` with fields not in the `ORDER BY` section of a table.
+:::
+
+## Limitations {#limitations}
+
+`PREWHERE` is only supported by tables from the [*MergeTree](../../../engines/table-engines/mergetree-family/index.md) family.
diff --git a/docs/en/reference/sql-reference/statements/select/sample.md b/docs/en/reference/sql-reference/statements/select/sample.md
new file mode 100644
index 00000000000..3673a49a9e9
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/sample.md
@@ -0,0 +1,114 @@
+---
+sidebar_label: SAMPLE
+---
+
+# SAMPLE Clause {#select-sample-clause}
+
+The `SAMPLE` clause allows for approximated `SELECT` query processing.
+
+When data sampling is enabled, the query is not performed on all the data, but only on a certain fraction of data (sample). For example, if you need to calculate statistics for all the visits, it is enough to execute the query on the 1/10 fraction of all the visits and then multiply the result by 10.
+
+Approximated query processing can be useful in the following cases:
+
+-   When you have strict latency requirements (like below 100ms) but you can’t justify the cost of additional hardware resources to meet them.
+-   When your raw data is not accurate, so approximation does not noticeably degrade the quality.
+-   Business requirements target approximate results (for cost-effectiveness, or to market exact results to premium users).
+
+:::note    
+You can only use sampling with the tables in the [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md) family, and only if the sampling expression was specified during table creation (see [MergeTree engine](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table)).
+:::
+
+The features of data sampling are listed below:
+
+-   Data sampling is a deterministic mechanism. The result of the same `SELECT .. SAMPLE` query is always the same.
+-   Sampling works consistently for different tables. For tables with a single sampling key, a sample with the same coefficient always selects the same subset of possible data. For example, a sample of user IDs takes rows with the same subset of all the possible user IDs from different tables. This means that you can use the sample in subqueries in the [IN](../../../sql-reference/operators/in.md) clause. Also, you can join samples using the [JOIN](../../../sql-reference/statements/select/join.md) clause.
+-   Sampling allows reading less data from a disk. Note that you must specify the sampling key correctly. For more information, see [Creating a MergeTree Table](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table).
+
+For the `SAMPLE` clause the following syntax is supported:
+
+| SAMPLE Clause Syntax | Description                  |
+|----------------------|------------------------------|
+| `SAMPLE k`   |  Here `k` is the number from 0 to 1. The query is executed on `k` fraction of data. For example, `SAMPLE 0.1` runs the query on 10% of data. [Read more](#select-sample-k)      |
+| `SAMPLE n`    |  Here `n` is a sufficiently large integer. The query is executed on a sample of at least `n` rows (but not significantly more than this). For example, `SAMPLE 10000000` runs the query on a minimum of 10,000,000 rows. [Read more](#select-sample-n)  |
+| `SAMPLE k OFFSET m`  |  Here `k` and `m` are the numbers from 0 to 1. The query is executed on a sample of `k` fraction of the data. The data used for the sample is offset by `m` fraction. [Read more](#select-sample-offset)  |
+
+
+## SAMPLE K {#select-sample-k}
+
+Here `k` is the number from 0 to 1 (both fractional and decimal notations are supported). For example, `SAMPLE 1/2` or `SAMPLE 0.5`.
+
+In a `SAMPLE k` clause, the sample is taken from the `k` fraction of data. The example is shown below:
+
+``` sql
+SELECT
+    Title,
+    count() * 10 AS PageViews
+FROM hits_distributed
+SAMPLE 0.1
+WHERE
+    CounterID = 34
+GROUP BY Title
+ORDER BY PageViews DESC LIMIT 1000
+```
+
+In this example, the query is executed on a sample from 0.1 (10%) of data. Values of aggregate functions are not corrected automatically, so to get an approximate result, the value `count()` is manually multiplied by 10.
+
+## SAMPLE N {#select-sample-n}
+
+Here `n` is a sufficiently large integer. For example, `SAMPLE 10000000`.
+
+In this case, the query is executed on a sample of at least `n` rows (but not significantly more than this). For example, `SAMPLE 10000000` runs the query on a minimum of 10,000,000 rows.
+
+Since the minimum unit for data reading is one granule (its size is set by the `index_granularity` setting), it makes sense to set a sample that is much larger than the size of the granule.
+
+When using the `SAMPLE n` clause, you do not know which relative percent of data was processed. So you do not know the coefficient the aggregate functions should be multiplied by. Use the `_sample_factor` virtual column to get the approximate result.
+
+The `_sample_factor` column contains relative coefficients that are calculated dynamically. This column is created automatically when you [create](../../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-creating-a-table) a table with the specified sampling key. The usage examples of the `_sample_factor` column are shown below.
+
+Let’s consider the table `visits`, which contains the statistics about site visits. The first example shows how to calculate the number of page views:
+
+``` sql
+SELECT sum(PageViews * _sample_factor)
+FROM visits
+SAMPLE 10000000
+```
+
+The next example shows how to calculate the total number of visits:
+
+``` sql
+SELECT sum(_sample_factor)
+FROM visits
+SAMPLE 10000000
+```
+
+The example below shows how to calculate the average session duration. Note that you do not need to use the relative coefficient to calculate the average values.
+
+``` sql
+SELECT avg(Duration)
+FROM visits
+SAMPLE 10000000
+```
+
+## SAMPLE K OFFSET M {#select-sample-offset}
+
+Here `k` and `m` are numbers from 0 to 1. Examples are shown below.
+
+**Example 1**
+
+``` sql
+SAMPLE 1/10
+```
+
+In this example, the sample is 1/10th of all data:
+
+`[++------------]`
+
+**Example 2**
+
+``` sql
+SAMPLE 1/10 OFFSET 1/2
+```
+
+Here, a sample of 10% is taken from the second half of the data.
+
+`[------++------]`
diff --git a/docs/en/reference/sql-reference/statements/select/union.md b/docs/en/reference/sql-reference/statements/select/union.md
new file mode 100644
index 00000000000..8a1c7a770c9
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/union.md
@@ -0,0 +1,87 @@
+---
+sidebar_label: UNION
+---
+
+# UNION Clause {#union-clause}
+
+You can use `UNION` with explicitly specifying `UNION ALL` or `UNION DISTINCT`.
+
+If you don't specify `ALL` or `DISTINCT`, it will depend on the `union_default_mode` setting. The difference between `UNION ALL` and `UNION DISTINCT` is that `UNION DISTINCT` will do a distinct transform for union result, it is equivalent to `SELECT DISTINCT` from a subquery containing `UNION ALL`.
+
+You can use `UNION` to combine any number of `SELECT` queries by extending their results. Example:
+
+``` sql
+SELECT CounterID, 1 AS table, toInt64(count()) AS c
+    FROM test.hits
+    GROUP BY CounterID
+
+UNION ALL
+
+SELECT CounterID, 2 AS table, sum(Sign) AS c
+    FROM test.visits
+    GROUP BY CounterID
+    HAVING c > 0
+```
+
+Result columns are matched by their index (order inside `SELECT`). If column names do not match, names for the final result are taken from the first query.
+
+Type casting is performed for unions. For example, if two queries being combined have the same field with non-`Nullable` and `Nullable` types from a compatible type, the resulting `UNION` has a `Nullable` type field.
+
+Queries that are parts of `UNION` can be enclosed in round brackets. [ORDER BY](../../../sql-reference/statements/select/order-by.md) and [LIMIT](../../../sql-reference/statements/select/limit.md) are applied to separate queries, not to the final result. If you need to apply a conversion to the final result, you can put all the queries with `UNION` in a subquery in the [FROM](../../../sql-reference/statements/select/from.md) clause.
+
+If you use `UNION` without explicitly specifying `UNION ALL` or `UNION DISTINCT`, you can specify the union mode using the [union_default_mode](../../../operations/settings/settings.md#union-default-mode) setting. The setting values can be `ALL`, `DISTINCT` or an empty string. However, if you use `UNION` with `union_default_mode` setting to empty string, it will throw an exception. The following examples demonstrate the results of queries with different values setting.
+
+Query:
+
+```sql
+SET union_default_mode = 'DISTINCT';
+SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 2;
+```
+
+Result:
+
+```text
+┌─1─┐
+│ 1 │
+└───┘
+┌─1─┐
+│ 2 │
+└───┘
+┌─1─┐
+│ 3 │
+└───┘
+```
+
+Query:
+
+```sql
+SET union_default_mode = 'ALL';
+SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 2;
+```
+
+Result:
+
+```text
+┌─1─┐
+│ 1 │
+└───┘
+┌─1─┐
+│ 2 │
+└───┘
+┌─1─┐
+│ 2 │
+└───┘
+┌─1─┐
+│ 3 │
+└───┘
+```
+
+Queries that are parts of `UNION/UNION ALL/UNION DISTINCT` can be run simultaneously, and their results can be mixed together.
+
+**See Also**
+
+-   [insert_null_as_default](../../../operations/settings/settings.md#insert_null_as_default) setting.
+-   [union_default_mode](../../../operations/settings/settings.md#union-default-mode) setting.
+
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/statements/select/union/) <!-- hide -->
diff --git a/docs/en/reference/sql-reference/statements/select/where.md b/docs/en/reference/sql-reference/statements/select/where.md
new file mode 100644
index 00000000000..c68f9d39d09
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/where.md
@@ -0,0 +1,57 @@
+---
+sidebar_label: WHERE
+---
+
+# WHERE Clause {#select-where}
+
+`WHERE` clause allows to filter the data that is coming from [FROM](../../../sql-reference/statements/select/from.md) clause of `SELECT`.
+
+If there is a `WHERE` clause, it must contain an expression with the `UInt8` type. This is usually an expression with comparison and logical operators. Rows where this expression evaluates to `0` are excluded from further transformations or result.
+
+`WHERE` expression is evaluated on the ability to use indexes and partition pruning, if the underlying table engine supports that.
+
+:::note    
+There is a filtering optimization called [PREWHERE](../../../sql-reference/statements/select/prewhere.md).
+:::
+
+If you need to test a value for [NULL](../../../sql-reference/syntax.md#null-literal), use [IS NULL](../../operators/index.md#operator-is-null) and [IS NOT NULL](../../operators/index.md#is-not-null) operators or [isNull](../../../sql-reference/functions/functions-for-nulls.md#isnull) and [isNotNull](../../../sql-reference/functions/functions-for-nulls.md#isnotnull) functions.
+Otherwise an expression with `NULL` never passes.
+
+**Example**
+
+To find numbers that are multiples of 3 and are greater than 10 execute the following query on the [numbers table](../../../sql-reference/table-functions/numbers.md):
+
+``` sql
+SELECT number FROM numbers(20) WHERE (number > 10) AND (number % 3 == 0);
+```
+
+Result:
+
+``` text
+┌─number─┐
+│     12 │
+│     15 │
+│     18 │
+└────────┘
+```
+
+Queries with `NULL` values:
+
+``` sql
+CREATE TABLE t_null(x Int8, y Nullable(Int8)) ENGINE=MergeTree() ORDER BY x;
+INSERT INTO t_null VALUES (1, NULL), (2, 3);
+
+SELECT * FROM t_null WHERE y IS NULL;
+SELECT * FROM t_null WHERE y != 0;
+```
+
+Result:
+
+``` text
+┌─x─┬────y─┐
+│ 1 │ ᴺᵁᴸᴸ │
+└───┴──────┘
+┌─x─┬─y─┐
+│ 2 │ 3 │
+└───┴───┘
+```
diff --git a/docs/en/reference/sql-reference/statements/select/with.md b/docs/en/reference/sql-reference/statements/select/with.md
new file mode 100644
index 00000000000..39fcb752980
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/select/with.md
@@ -0,0 +1,70 @@
+---
+sidebar_label: WITH
+---
+
+# WITH Clause {#with-clause}
+
+ClickHouse supports Common Table Expressions ([CTE](https://en.wikipedia.org/wiki/Hierarchical_and_recursive_queries_in_SQL)), that is provides to use results of `WITH` clause in the rest of `SELECT` query. Named subqueries can be included to the current and child query context in places where table objects are allowed. Recursion is prevented by hiding the current level CTEs from the WITH expression.
+
+## Syntax
+
+``` sql
+WITH <expression> AS <identifier>
+```
+or
+``` sql
+WITH <identifier> AS <subquery expression>
+```
+
+## Examples {#examples}
+
+**Example 1:** Using constant expression as “variable”
+
+``` sql
+WITH '2019-08-01 15:23:00' as ts_upper_bound
+SELECT *
+FROM hits
+WHERE
+    EventDate = toDate(ts_upper_bound) AND
+    EventTime <= ts_upper_bound;
+```
+
+**Example 2:** Evicting a sum(bytes) expression result from the SELECT clause column list
+
+``` sql
+WITH sum(bytes) as s
+SELECT
+    formatReadableSize(s),
+    table
+FROM system.parts
+GROUP BY table
+ORDER BY s;
+```
+
+**Example 3:** Using results of a scalar subquery
+
+``` sql
+/* this example would return TOP 10 of most huge tables */
+WITH
+    (
+        SELECT sum(bytes)
+        FROM system.parts
+        WHERE active
+    ) AS total_disk_usage
+SELECT
+    (sum(bytes) / total_disk_usage) * 100 AS table_disk_usage,
+    table
+FROM system.parts
+GROUP BY table
+ORDER BY table_disk_usage DESC
+LIMIT 10;
+```
+
+**Example 4:** Reusing expression in a subquery
+
+``` sql
+WITH test1 AS (SELECT i + 1, j + 1 FROM test1)
+SELECT * FROM test1;
+```
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/statements/select/with/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/statements/set-role.md b/docs/en/reference/sql-reference/statements/set-role.md
new file mode 100644
index 00000000000..cac7ca28b92
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/set-role.md
@@ -0,0 +1,48 @@
+---
+sidebar_position: 51
+sidebar_label: SET ROLE
+---
+
+# SET ROLE Statement {#set-role-statement}
+
+Activates roles for the current user.
+
+``` sql
+SET ROLE {DEFAULT | NONE | role [,...] | ALL | ALL EXCEPT role [,...]}
+```
+
+## SET DEFAULT ROLE {#set-default-role-statement}
+
+Sets default roles to a user.
+
+Default roles are automatically activated at user login. You can set as default only the previously granted roles. If the role isn’t granted to a user, ClickHouse throws an exception.
+
+``` sql
+SET DEFAULT ROLE {NONE | role [,...] | ALL | ALL EXCEPT role [,...]} TO {user|CURRENT_USER} [,...]
+```
+
+## Examples {#set-default-role-examples}
+
+Set multiple default roles to a user:
+
+``` sql
+SET DEFAULT ROLE role1, role2, ... TO user
+```
+
+Set all the granted roles as default to a user:
+
+``` sql
+SET DEFAULT ROLE ALL TO user
+```
+
+Purge default roles from a user:
+
+``` sql
+SET DEFAULT ROLE NONE TO user
+```
+
+Set all the granted roles as default excepting some of them:
+
+``` sql
+SET DEFAULT ROLE ALL EXCEPT role1, role2 TO user
+```
diff --git a/docs/en/reference/sql-reference/statements/set.md b/docs/en/reference/sql-reference/statements/set.md
new file mode 100644
index 00000000000..d2a1d30c797
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/set.md
@@ -0,0 +1,20 @@
+---
+sidebar_position: 50
+sidebar_label: SET
+---
+
+# SET Statement {#query-set}
+
+``` sql
+SET param = value
+```
+
+Assigns `value` to the `param` [setting](../../operations/settings/index.md) for the current session. You cannot change [server settings](../../operations/server-configuration-parameters/index.md) this way.
+
+You can also set all the values from the specified settings profile in a single query.
+
+``` sql
+SET profile = 'profile-name-from-the-settings-file'
+```
+
+For more information, see [Settings](../../operations/settings/settings.md).
diff --git a/docs/en/reference/sql-reference/statements/show.md b/docs/en/reference/sql-reference/statements/show.md
new file mode 100644
index 00000000000..75c5c121946
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/show.md
@@ -0,0 +1,499 @@
+---
+sidebar_position: 37
+sidebar_label: SHOW
+---
+
+# SHOW Statements {#show-queries}
+
+## SHOW CREATE TABLE {#show-create-table}
+
+``` sql
+SHOW CREATE [TEMPORARY] [TABLE|DICTIONARY|VIEW] [db.]table|view [INTO OUTFILE filename] [FORMAT format]
+```
+
+Returns a single `String`-type ‘statement’ column, which contains a single value – the `CREATE` query used for creating the specified object.
+
+Note that if you use this statement to get `CREATE` query of system tables, you will get a *fake* query, which only declares table structure, but cannot be used to create table.
+
+## SHOW DATABASES {#show-databases}
+
+Prints a list of all databases.
+
+```sql
+SHOW DATABASES [LIKE | ILIKE | NOT LIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE filename] [FORMAT format]
+```
+
+This statement is identical to the query:
+
+```sql
+SELECT name FROM system.databases [WHERE name LIKE | ILIKE | NOT LIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE filename] [FORMAT format]
+```
+
+### Examples {#examples}
+
+Getting database names, containing the symbols sequence 'de' in their names:
+
+``` sql
+SHOW DATABASES LIKE '%de%'
+```
+
+Result:
+
+``` text
+┌─name────┐
+│ default │
+└─────────┘
+```
+
+Getting database names, containing symbols sequence 'de' in their names, in the case insensitive manner:
+
+``` sql
+SHOW DATABASES ILIKE '%DE%'
+```
+
+Result:
+
+``` text
+┌─name────┐
+│ default │
+└─────────┘
+```
+
+Getting database names, not containing the symbols sequence 'de' in their names:
+
+``` sql
+SHOW DATABASES NOT LIKE '%de%'
+```
+
+Result:
+
+``` text
+┌─name───────────────────────────┐
+│ _temporary_and_external_tables │
+│ system                         │
+│ test                           │
+│ tutorial                       │
+└────────────────────────────────┘
+```
+
+Getting the first two rows from database names:
+
+``` sql
+SHOW DATABASES LIMIT 2
+```
+
+Result:
+
+``` text
+┌─name───────────────────────────┐
+│ _temporary_and_external_tables │
+│ default                        │
+└────────────────────────────────┘
+```
+
+### See Also {#see-also}
+
+-   [CREATE DATABASE](https://clickhouse.com/docs/en/sql-reference/statements/create/database/#query-language-create-database)
+
+## SHOW PROCESSLIST {#show-processlist}
+
+``` sql
+SHOW PROCESSLIST [INTO OUTFILE filename] [FORMAT format]
+```
+
+Outputs the content of the [system.processes](../../operations/system-tables/processes.md#system_tables-processes) table, that contains a list of queries that is being processed at the moment, excepting `SHOW PROCESSLIST` queries.
+
+The `SELECT * FROM system.processes` query returns data about all the current queries.
+
+Tip (execute in the console):
+
+``` bash
+$ watch -n1 "clickhouse-client --query='SHOW PROCESSLIST'"
+```
+
+## SHOW TABLES {#show-tables}
+
+Displays a list of tables.
+
+```sql
+SHOW [TEMPORARY] TABLES [{FROM | IN} <db>] [LIKE | ILIKE | NOT LIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
+```
+
+If the `FROM` clause is not specified, the query returns the list of tables from the current database.
+
+This statement is identical to the query:
+
+```sql
+SELECT name FROM system.tables [WHERE name LIKE | ILIKE | NOT LIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
+```
+
+### Examples {#examples}
+
+Getting table names, containing the symbols sequence 'user' in their names:
+
+``` sql
+SHOW TABLES FROM system LIKE '%user%'
+```
+
+Result:
+
+``` text
+┌─name─────────────┐
+│ user_directories │
+│ users            │
+└──────────────────┘
+```
+
+Getting table names, containing sequence 'user' in their names, in the case insensitive manner:
+
+``` sql
+SHOW TABLES FROM system ILIKE '%USER%'
+```
+
+Result:
+
+``` text
+┌─name─────────────┐
+│ user_directories │
+│ users            │
+└──────────────────┘
+```
+
+Getting table names, not containing the symbol sequence 's' in their names:
+
+``` sql
+SHOW TABLES FROM system NOT LIKE '%s%'
+```
+
+Result:
+
+``` text
+┌─name─────────┐
+│ metric_log   │
+│ metric_log_0 │
+│ metric_log_1 │
+└──────────────┘
+```
+
+Getting the first two rows from table names:
+
+``` sql
+SHOW TABLES FROM system LIMIT 2
+```
+
+Result:
+
+``` text
+┌─name───────────────────────────┐
+│ aggregate_function_combinators │
+│ asynchronous_metric_log        │
+└────────────────────────────────┘
+```
+
+### See Also {#see-also}
+
+-   [Create Tables](https://clickhouse.com/docs/en/getting-started/tutorial/#create-tables)
+-   [SHOW CREATE TABLE](https://clickhouse.com/docs/en/sql-reference/statements/show/#show-create-table)
+
+## SHOW DICTIONARIES {#show-dictionaries}
+
+Displays a list of [external dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md).
+
+``` sql
+SHOW DICTIONARIES [FROM <db>] [LIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
+```
+
+If the `FROM` clause is not specified, the query returns the list of dictionaries from the current database.
+
+You can get the same results as the `SHOW DICTIONARIES` query in the following way:
+
+``` sql
+SELECT name FROM system.dictionaries WHERE database = <db> [AND name LIKE <pattern>] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
+```
+
+**Example**
+
+The following query selects the first two rows from the list of tables in the `system` database, whose names contain `reg`.
+
+``` sql
+SHOW DICTIONARIES FROM db LIKE '%reg%' LIMIT 2
+```
+
+``` text
+┌─name─────────┐
+│ regions      │
+│ region_names │
+└──────────────┘
+```
+
+## SHOW GRANTS {#show-grants-statement}
+
+Shows privileges for a user.
+
+### Syntax {#show-grants-syntax}
+
+``` sql
+SHOW GRANTS [FOR user1 [, user2 ...]]
+```
+
+If user is not specified, the query returns privileges for the current user.
+
+## SHOW CREATE USER {#show-create-user-statement}
+
+Shows parameters that were used at a [user creation](../../sql-reference/statements/create/user.md).
+
+`SHOW CREATE USER` does not output user passwords.
+
+### Syntax {#show-create-user-syntax}
+
+``` sql
+SHOW CREATE USER [name1 [, name2 ...] | CURRENT_USER]
+```
+
+## SHOW CREATE ROLE {#show-create-role-statement}
+
+Shows parameters that were used at a [role creation](../../sql-reference/statements/create/role.md).
+
+### Syntax {#show-create-role-syntax}
+
+``` sql
+SHOW CREATE ROLE name1 [, name2 ...]
+```
+
+## SHOW CREATE ROW POLICY {#show-create-row-policy-statement}
+
+Shows parameters that were used at a [row policy creation](../../sql-reference/statements/create/row-policy.md).
+
+### Syntax {#show-create-row-policy-syntax}
+
+``` sql
+SHOW CREATE [ROW] POLICY name ON [database1.]table1 [, [database2.]table2 ...]
+```
+
+## SHOW CREATE QUOTA {#show-create-quota-statement}
+
+Shows parameters that were used at a [quota creation](../../sql-reference/statements/create/quota.md).
+
+### Syntax {#show-create-quota-syntax}
+
+``` sql
+SHOW CREATE QUOTA [name1 [, name2 ...] | CURRENT]
+```
+
+## SHOW CREATE SETTINGS PROFILE {#show-create-settings-profile-statement}
+
+Shows parameters that were used at a [settings profile creation](../../sql-reference/statements/create/settings-profile.md).
+
+### Syntax {#show-create-settings-profile-syntax}
+
+``` sql
+SHOW CREATE [SETTINGS] PROFILE name1 [, name2 ...]
+```
+
+## SHOW USERS {#show-users-statement}
+
+Returns a list of [user account](../../operations/access-rights.md#user-account-management) names. To view user accounts parameters, see the system table [system.users](../../operations/system-tables/users.md#system_tables-users).
+
+### Syntax {#show-users-syntax}
+
+``` sql
+SHOW USERS
+```
+
+## SHOW ROLES {#show-roles-statement}
+
+Returns a list of [roles](../../operations/access-rights.md#role-management). To view another parameters, see system tables [system.roles](../../operations/system-tables/roles.md#system_tables-roles) and [system.role-grants](../../operations/system-tables/role-grants.md#system_tables-role_grants).
+
+### Syntax {#show-roles-syntax}
+
+``` sql
+SHOW [CURRENT|ENABLED] ROLES
+```
+## SHOW PROFILES {#show-profiles-statement}
+
+Returns a list of [setting profiles](../../operations/access-rights.md#settings-profiles-management). To view user accounts parameters, see the system table [settings_profiles](../../operations/system-tables/settings_profiles.md#system_tables-settings_profiles).
+
+### Syntax {#show-profiles-syntax}
+
+``` sql
+SHOW [SETTINGS] PROFILES
+```
+
+## SHOW POLICIES {#show-policies-statement}
+
+Returns a list of [row policies](../../operations/access-rights.md#row-policy-management) for the specified table. To view user accounts parameters, see the system table [system.row_policies](../../operations/system-tables/row_policies.md#system_tables-row_policies).
+
+### Syntax {#show-policies-syntax}
+
+``` sql
+SHOW [ROW] POLICIES [ON [db.]table]
+```
+
+## SHOW QUOTAS {#show-quotas-statement}
+
+Returns a list of [quotas](../../operations/access-rights.md#quotas-management). To view quotas parameters, see the system table [system.quotas](../../operations/system-tables/quotas.md#system_tables-quotas).
+
+### Syntax {#show-quotas-syntax}
+
+``` sql
+SHOW QUOTAS
+```
+
+## SHOW QUOTA {#show-quota-statement}
+
+Returns a [quota](../../operations/quotas.md) consumption for all users or for current user. To view another parameters, see system tables [system.quotas_usage](../../operations/system-tables/quotas_usage.md#system_tables-quotas_usage) and [system.quota_usage](../../operations/system-tables/quota_usage.md#system_tables-quota_usage).
+
+### Syntax {#show-quota-syntax}
+
+``` sql
+SHOW [CURRENT] QUOTA
+```
+## SHOW ACCESS {#show-access-statement}
+
+Shows all [users](../../operations/access-rights.md#user-account-management), [roles](../../operations/access-rights.md#role-management), [profiles](../../operations/access-rights.md#settings-profiles-management), etc. and all their [grants](../../sql-reference/statements/grant.md#grant-privileges).
+
+### Syntax {#show-access-syntax}
+
+``` sql
+SHOW ACCESS
+```
+## SHOW CLUSTER(s) {#show-cluster-statement}
+
+Returns a list of clusters. All available clusters are listed in the [system.clusters](../../operations/system-tables/clusters.md) table.
+
+:::note    
+`SHOW CLUSTER name` query displays the contents of system.clusters table for this cluster.
+:::
+
+### Syntax {#show-cluster-syntax}
+
+``` sql
+SHOW CLUSTER '<name>'
+SHOW CLUSTERS [LIKE|NOT LIKE '<pattern>'] [LIMIT <N>]
+```
+### Examples {#show-cluster-examples}
+
+Query:
+
+``` sql
+SHOW CLUSTERS;
+```
+
+Result:
+
+```text
+┌─cluster──────────────────────────────────────┐
+│ test_cluster_two_shards                      │
+│ test_cluster_two_shards_internal_replication │
+│ test_cluster_two_shards_localhost            │
+│ test_shard_localhost                         │
+│ test_shard_localhost_secure                  │
+│ test_unavailable_shard                       │
+└──────────────────────────────────────────────┘
+```
+
+Query:
+
+``` sql
+SHOW CLUSTERS LIKE 'test%' LIMIT 1;
+```
+
+Result:
+
+```text
+┌─cluster─────────────────┐
+│ test_cluster_two_shards │
+└─────────────────────────┘
+```
+
+Query:
+
+``` sql
+SHOW CLUSTER 'test_shard_localhost' FORMAT Vertical;
+```
+
+Result:
+
+```text
+Row 1:
+──────
+cluster:                 test_shard_localhost
+shard_num:               1
+shard_weight:            1
+replica_num:             1
+host_name:               localhost
+host_address:            127.0.0.1
+port:                    9000
+is_local:                1
+user:                    default
+default_database:
+errors_count:            0
+estimated_recovery_time: 0
+```
+
+## SHOW SETTINGS {#show-settings}
+
+Returns a list of system settings and their values. Selects data from the [system.settings](../../operations/system-tables/settings.md) table.
+
+**Syntax**
+
+```sql
+SHOW [CHANGED] SETTINGS LIKE|ILIKE <name>
+```
+
+**Clauses**
+
+`LIKE|ILIKE` allow to specify a matching pattern for the setting name. It can contain globs such as `%` or `_`. `LIKE` clause is case-sensitive, `ILIKE` — case insensitive.
+
+When the `CHANGED` clause is used, the query returns only settings changed from their default values.
+
+**Examples**
+
+Query with the `LIKE` clause:
+
+```sql
+SHOW SETTINGS LIKE 'send_timeout';
+```
+Result:
+
+```text
+┌─name─────────┬─type────┬─value─┐
+│ send_timeout │ Seconds │ 300   │
+└──────────────┴─────────┴───────┘
+```
+
+Query with the `ILIKE` clause:
+
+```sql
+SHOW SETTINGS ILIKE '%CONNECT_timeout%'
+```
+
+Result:
+
+```text
+┌─name────────────────────────────────────┬─type─────────┬─value─┐
+│ connect_timeout                         │ Seconds      │ 10    │
+│ connect_timeout_with_failover_ms        │ Milliseconds │ 50    │
+│ connect_timeout_with_failover_secure_ms │ Milliseconds │ 100   │
+└─────────────────────────────────────────┴──────────────┴───────┘
+```
+
+Query with the `CHANGED` clause:
+
+```sql
+SHOW CHANGED SETTINGS ILIKE '%MEMORY%'
+```
+
+Result:
+
+```text
+┌─name─────────────┬─type───┬─value───────┐
+│ max_memory_usage │ UInt64 │ 10000000000 │
+└──────────────────┴────────┴─────────────┘
+```
+
+**See Also**
+
+-   [system.settings](../../operations/system-tables/settings.md) table
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/statements/show/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/statements/system.md b/docs/en/reference/sql-reference/statements/system.md
new file mode 100644
index 00000000000..1d638ab3965
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/system.md
@@ -0,0 +1,371 @@
+---
+sidebar_position: 36
+sidebar_label: SYSTEM
+---
+
+# SYSTEM Statements {#query-language-system}
+
+The list of available `SYSTEM` statements:
+
+-   [RELOAD EMBEDDED DICTIONARIES](#query_language-system-reload-emdedded-dictionaries)
+-   [RELOAD DICTIONARIES](#query_language-system-reload-dictionaries)
+-   [RELOAD DICTIONARY](#query_language-system-reload-dictionary)
+-   [RELOAD MODELS](#query_language-system-reload-models)
+-   [RELOAD MODEL](#query_language-system-reload-model)
+-   [RELOAD FUNCTIONS](#query_language-system-reload-functions)
+-   [RELOAD FUNCTION](#query_language-system-reload-functions)
+-   [DROP DNS CACHE](#query_language-system-drop-dns-cache)
+-   [DROP MARK CACHE](#query_language-system-drop-mark-cache)
+-   [DROP UNCOMPRESSED CACHE](#query_language-system-drop-uncompressed-cache)
+-   [DROP COMPILED EXPRESSION CACHE](#query_language-system-drop-compiled-expression-cache)
+-   [DROP REPLICA](#query_language-system-drop-replica)
+-   [FLUSH LOGS](#query_language-system-flush_logs)
+-   [RELOAD CONFIG](#query_language-system-reload-config)
+-   [SHUTDOWN](#query_language-system-shutdown)
+-   [KILL](#query_language-system-kill)
+-   [STOP DISTRIBUTED SENDS](#query_language-system-stop-distributed-sends)
+-   [FLUSH DISTRIBUTED](#query_language-system-flush-distributed)
+-   [START DISTRIBUTED SENDS](#query_language-system-start-distributed-sends)
+-   [STOP MERGES](#query_language-system-stop-merges)
+-   [START MERGES](#query_language-system-start-merges)
+-   [STOP TTL MERGES](#query_language-stop-ttl-merges)
+-   [START TTL MERGES](#query_language-start-ttl-merges)
+-   [STOP MOVES](#query_language-stop-moves)
+-   [START MOVES](#query_language-start-moves)
+-   [STOP FETCHES](#query_language-system-stop-fetches)
+-   [START FETCHES](#query_language-system-start-fetches)
+-   [STOP REPLICATED SENDS](#query_language-system-start-replicated-sends)
+-   [START REPLICATED SENDS](#query_language-system-start-replicated-sends)
+-   [STOP REPLICATION QUEUES](#query_language-system-stop-replication-queues)
+-   [START REPLICATION QUEUES](#query_language-system-start-replication-queues)
+-   [SYNC REPLICA](#query_language-system-sync-replica)
+-   [RESTART REPLICA](#query_language-system-restart-replica)
+-   [RESTORE REPLICA](#query_language-system-restore-replica)
+-   [RESTART REPLICAS](#query_language-system-restart-replicas)
+
+## RELOAD EMBEDDED DICTIONARIES {#query_language-system-reload-emdedded-dictionaries}
+
+Reload all [Internal dictionaries](../../sql-reference/dictionaries/internal-dicts.md).
+By default, internal dictionaries are disabled.
+Always returns `Ok.` regardless of the result of the internal dictionary update.
+
+## RELOAD DICTIONARIES {#query_language-system-reload-dictionaries}
+
+Reloads all dictionaries that have been successfully loaded before.
+By default, dictionaries are loaded lazily (see [dictionaries_lazy_load](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-dictionaries_lazy_load)), so instead of being loaded automatically at startup, they are initialized on first access through dictGet function or SELECT from tables with ENGINE = Dictionary. The `SYSTEM RELOAD DICTIONARIES` query reloads such dictionaries (LOADED).
+Always returns `Ok.` regardless of the result of the dictionary update.
+
+## RELOAD DICTIONARY {#query_language-system-reload-dictionary}
+
+Completely reloads a dictionary `dictionary_name`, regardless of the state of the dictionary (LOADED / NOT_LOADED / FAILED).
+Always returns `Ok.` regardless of the result of updating the dictionary.
+The status of the dictionary can be checked by querying the `system.dictionaries` table.
+
+``` sql
+SELECT name, status FROM system.dictionaries;
+```
+
+## RELOAD MODELS {#query_language-system-reload-models}
+
+Reloads all [CatBoost](../../../guides/developer/apply-catboost-model.md) models if the configuration was updated without restarting the server.
+
+**Syntax**
+
+```sql
+SYSTEM RELOAD MODELS [ON CLUSTER cluster_name]
+```
+
+## RELOAD MODEL {#query_language-system-reload-model}
+
+Completely reloads a CatBoost model `model_name` if the configuration was updated without restarting the server.
+
+**Syntax**
+
+```sql
+SYSTEM RELOAD MODEL [ON CLUSTER cluster_name] <model_name>
+```
+
+## RELOAD FUNCTIONS {#query_language-system-reload-functions}
+
+Reloads all registered [executable user defined functions](../functions/index.md#executable-user-defined-functions) or one of them from a configuration file.
+
+**Syntax**
+
+```sql
+RELOAD FUNCTIONS [ON CLUSTER cluster_name]
+RELOAD FUNCTION [ON CLUSTER cluster_name] function_name
+```
+
+## DROP DNS CACHE {#query_language-system-drop-dns-cache}
+
+Resets ClickHouse’s internal DNS cache. Sometimes (for old ClickHouse versions) it is necessary to use this command when changing the infrastructure (changing the IP address of another ClickHouse server or the server used by dictionaries).
+
+For more convenient (automatic) cache management, see disable_internal_dns_cache, dns_cache_update_period parameters.
+
+## DROP MARK CACHE {#query_language-system-drop-mark-cache}
+
+Resets the mark cache. Used in development of ClickHouse and performance tests.
+
+## DROP REPLICA {#query_language-system-drop-replica}
+
+Dead replicas can be dropped using following syntax:
+
+``` sql
+SYSTEM DROP REPLICA 'replica_name' FROM TABLE database.table;
+SYSTEM DROP REPLICA 'replica_name' FROM DATABASE database;
+SYSTEM DROP REPLICA 'replica_name';
+SYSTEM DROP REPLICA 'replica_name' FROM ZKPATH '/path/to/table/in/zk';
+```
+
+Queries will remove the replica path in ZooKeeper. It is useful when the replica is dead and its metadata cannot be removed from ZooKeeper by `DROP TABLE` because there is no such table anymore. It will only drop the inactive/stale replica, and it cannot drop local replica, please use `DROP TABLE` for that. `DROP REPLICA` does not drop any tables and does not remove any data or metadata from disk.
+
+The first one removes metadata of `'replica_name'` replica of `database.table` table.
+The second one does the same for all replicated tables in the database.
+The third one does the same for all replicated tables on the local server.
+The fourth one is useful to remove metadata of dead replica when all other replicas of a table were dropped. It requires the table path to be specified explicitly. It must be the same path as was passed to the first argument of `ReplicatedMergeTree` engine on table creation.
+
+## DROP UNCOMPRESSED CACHE {#query_language-system-drop-uncompressed-cache}
+
+Reset the uncompressed data cache. Used in development of ClickHouse and performance tests.
+For manage uncompressed data cache parameters use following server level settings [uncompressed_cache_size](../../operations/server-configuration-parameters/settings.md#server-settings-uncompressed_cache_size) and query/user/profile level settings [use_uncompressed_cache](../../operations/settings/settings.md#setting-use_uncompressed_cache)
+
+## DROP COMPILED EXPRESSION CACHE {#query_language-system-drop-compiled-expression-cache}
+
+Reset the compiled expression cache. Used in development of ClickHouse and performance tests.
+Compiled expression cache used when query/user/profile enable option [compile-expressions](../../operations/settings/settings.md#compile-expressions)
+
+## FLUSH LOGS {#query_language-system-flush_logs}
+
+Flushes buffers of log messages to system tables (e.g. system.query_log). Allows you to not wait 7.5 seconds when debugging.
+This will also create system tables even if message queue is empty.
+
+## RELOAD CONFIG {#query_language-system-reload-config}
+
+Reloads ClickHouse configuration. Used when configuration is stored in ZooKeeper.
+
+## SHUTDOWN {#query_language-system-shutdown}
+
+Normally shuts down ClickHouse (like `service clickhouse-server stop` / `kill {$pid_clickhouse-server}`)
+
+## KILL {#query_language-system-kill}
+
+Aborts ClickHouse process (like `kill -9 {$ pid_clickhouse-server}`)
+
+## Managing Distributed Tables {#query-language-system-distributed}
+
+ClickHouse can manage [distributed](../../engines/table-engines/special/distributed.md) tables. When a user inserts data into these tables, ClickHouse first creates a queue of the data that should be sent to cluster nodes, then asynchronously sends it. You can manage queue processing with the [STOP DISTRIBUTED SENDS](#query_language-system-stop-distributed-sends), [FLUSH DISTRIBUTED](#query_language-system-flush-distributed), and [START DISTRIBUTED SENDS](#query_language-system-start-distributed-sends) queries. You can also synchronously insert distributed data with the [insert_distributed_sync](../../operations/settings/settings.md#insert_distributed_sync) setting.
+
+### STOP DISTRIBUTED SENDS {#query_language-system-stop-distributed-sends}
+
+Disables background data distribution when inserting data into distributed tables.
+
+``` sql
+SYSTEM STOP DISTRIBUTED SENDS [db.]<distributed_table_name>
+```
+
+### FLUSH DISTRIBUTED {#query_language-system-flush-distributed}
+
+Forces ClickHouse to send data to cluster nodes synchronously. If any nodes are unavailable, ClickHouse throws an exception and stops query execution. You can retry the query until it succeeds, which will happen when all nodes are back online.
+
+``` sql
+SYSTEM FLUSH DISTRIBUTED [db.]<distributed_table_name>
+```
+
+### START DISTRIBUTED SENDS {#query_language-system-start-distributed-sends}
+
+Enables background data distribution when inserting data into distributed tables.
+
+``` sql
+SYSTEM START DISTRIBUTED SENDS [db.]<distributed_table_name>
+```
+
+## Managing MergeTree Tables {#query-language-system-mergetree}
+
+ClickHouse can manage background processes in [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables.
+
+### STOP MERGES {#query_language-system-stop-merges}
+
+Provides possibility to stop background merges for tables in the MergeTree family:
+
+``` sql
+SYSTEM STOP MERGES [ON VOLUME <volume_name> | [db.]merge_tree_family_table_name]
+```
+
+:::note    
+`DETACH / ATTACH` table will start background merges for the table even in case when merges have been stopped for all MergeTree tables before.
+:::
+
+### START MERGES {#query_language-system-start-merges}
+
+Provides possibility to start background merges for tables in the MergeTree family:
+
+``` sql
+SYSTEM START MERGES [ON VOLUME <volume_name> | [db.]merge_tree_family_table_name]
+```
+
+### STOP TTL MERGES {#query_language-stop-ttl-merges}
+
+Provides possibility to stop background delete old data according to [TTL expression](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl) for tables in the MergeTree family:
+Returns `Ok.` even if table does not exist or table has not MergeTree engine. Returns error when database does not exist:
+
+``` sql
+SYSTEM STOP TTL MERGES [[db.]merge_tree_family_table_name]
+```
+
+### START TTL MERGES {#query_language-start-ttl-merges}
+
+Provides possibility to start background delete old data according to [TTL expression](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl) for tables in the MergeTree family:
+Returns `Ok.` even if table does not exist. Returns error when database does not exist:
+
+``` sql
+SYSTEM START TTL MERGES [[db.]merge_tree_family_table_name]
+```
+
+### STOP MOVES {#query_language-stop-moves}
+
+Provides possibility to stop background move data according to [TTL table expression with TO VOLUME or TO DISK clause](../../engines/table-engines/mergetree-family/mergetree.md#mergetree-table-ttl) for tables in the MergeTree family:
+Returns `Ok.` even if table does not exist. Returns error when database does not exist:
+
+``` sql
+SYSTEM STOP MOVES [[db.]merge_tree_family_table_name]
+```
+
+### START MOVES {#query_language-start-moves}
+
+Provides possibility to start background move data according to [TTL table expression with TO VOLUME and TO DISK clause](../../engines/table-engines/mergetree-family/mergetree.md#mergetree-table-ttl) for tables in the MergeTree family:
+Returns `Ok.` even if table does not exist. Returns error when database does not exist:
+
+``` sql
+SYSTEM START MOVES [[db.]merge_tree_family_table_name]
+```
+
+## Managing ReplicatedMergeTree Tables {#query-language-system-replicated}
+
+ClickHouse can manage background replication related processes in [ReplicatedMergeTree](../../engines/table-engines/mergetree-family/replication.md#table_engines-replication) tables.
+
+### STOP FETCHES {#query_language-system-stop-fetches}
+
+Provides possibility to stop background fetches for inserted parts for tables in the `ReplicatedMergeTree` family:
+Always returns `Ok.` regardless of the table engine and even if table or database does not exist.
+
+``` sql
+SYSTEM STOP FETCHES [[db.]replicated_merge_tree_family_table_name]
+```
+
+### START FETCHES {#query_language-system-start-fetches}
+
+Provides possibility to start background fetches for inserted parts for tables in the `ReplicatedMergeTree` family:
+Always returns `Ok.` regardless of the table engine and even if table or database does not exist.
+
+``` sql
+SYSTEM START FETCHES [[db.]replicated_merge_tree_family_table_name]
+```
+
+### STOP REPLICATED SENDS {#query_language-system-start-replicated-sends}
+
+Provides possibility to stop background sends to other replicas in cluster for new inserted parts for tables in the `ReplicatedMergeTree` family:
+
+``` sql
+SYSTEM STOP REPLICATED SENDS [[db.]replicated_merge_tree_family_table_name]
+```
+
+### START REPLICATED SENDS {#query_language-system-start-replicated-sends}
+
+Provides possibility to start background sends to other replicas in cluster for new inserted parts for tables in the `ReplicatedMergeTree` family:
+
+``` sql
+SYSTEM START REPLICATED SENDS [[db.]replicated_merge_tree_family_table_name]
+```
+
+### STOP REPLICATION QUEUES {#query_language-system-stop-replication-queues}
+
+Provides possibility to stop background fetch tasks from replication queues which stored in Zookeeper for tables in the `ReplicatedMergeTree` family. Possible background tasks types - merges, fetches, mutation, DDL statements with ON CLUSTER clause:
+
+``` sql
+SYSTEM STOP REPLICATION QUEUES [[db.]replicated_merge_tree_family_table_name]
+```
+
+### START REPLICATION QUEUES {#query_language-system-start-replication-queues}
+
+Provides possibility to start background fetch tasks from replication queues which stored in Zookeeper for tables in the `ReplicatedMergeTree` family. Possible background tasks types - merges, fetches, mutation, DDL statements with ON CLUSTER clause:
+
+``` sql
+SYSTEM START REPLICATION QUEUES [[db.]replicated_merge_tree_family_table_name]
+```
+
+### SYNC REPLICA {#query_language-system-sync-replica}
+
+Wait until a `ReplicatedMergeTree` table will be synced with other replicas in a cluster. Will run until `receive_timeout` if fetches currently disabled for the table.
+
+``` sql
+SYSTEM SYNC REPLICA [db.]replicated_merge_tree_family_table_name
+```
+
+After running this statement the `[db.]replicated_merge_tree_family_table_name` fetches commands from the common replicated log into its own replication queue, and then the query waits till the replica processes all of the fetched commands.
+
+### RESTART REPLICA {#query_language-system-restart-replica}
+
+Provides possibility to reinitialize Zookeeper sessions state for `ReplicatedMergeTree` table, will compare current state with Zookeeper as source of true and add tasks to Zookeeper queue if needed.
+Initialization replication queue based on ZooKeeper date happens in the same way as `ATTACH TABLE` statement. For a short time the table will be unavailable for any operations.
+
+``` sql
+SYSTEM RESTART REPLICA [db.]replicated_merge_tree_family_table_name
+```
+
+### RESTORE REPLICA {#query_language-system-restore-replica}
+
+Restores a replica if data is [possibly] present but Zookeeper metadata is lost.
+
+Works only on readonly `ReplicatedMergeTree` tables.
+
+One may execute query after:
+
+  - ZooKeeper root `/` loss.
+  - Replicas path `/replicas` loss.
+  - Individual replica path `/replicas/replica_name/` loss.
+
+Replica attaches locally found parts and sends info about them to Zookeeper.
+Parts present on a replica before metadata loss are not re-fetched from other ones if not being outdated (so replica restoration does not mean re-downloading all data over the network).
+
+:::warning    
+Parts in all states are moved to `detached/` folder. Parts active before data loss (committed) are attached.
+:::
+
+**Syntax**
+
+```sql
+SYSTEM RESTORE REPLICA [db.]replicated_merge_tree_family_table_name [ON CLUSTER cluster_name]
+```
+
+Alternative syntax:
+
+```sql
+SYSTEM RESTORE REPLICA [ON CLUSTER cluster_name] [db.]replicated_merge_tree_family_table_name
+```
+
+**Example**
+
+Creating a table on multiple servers. After the replica's metadata in ZooKeeper is lost, the table will attach as read-only as metadata is missing. The last query needs to execute on every replica.
+
+```sql
+CREATE TABLE test(n UInt32)
+ENGINE = ReplicatedMergeTree('/clickhouse/tables/test/', '{replica}')
+ORDER BY n PARTITION BY n % 10;
+
+INSERT INTO test SELECT * FROM numbers(1000);
+
+-- zookeeper_delete_path("/clickhouse/tables/test", recursive=True) <- root loss.
+
+SYSTEM RESTART REPLICA test;
+SYSTEM RESTORE REPLICA test;
+```
+
+Another way:
+
+```sql
+SYSTEM RESTORE REPLICA test ON CLUSTER cluster;
+```
+
+### RESTART REPLICAS {#query_language-system-restart-replicas}
+
+Provides possibility to reinitialize Zookeeper sessions state for all `ReplicatedMergeTree` tables, will compare current state with Zookeeper as source of true and add tasks to Zookeeper queue if needed
diff --git a/docs/en/reference/sql-reference/statements/truncate.md b/docs/en/reference/sql-reference/statements/truncate.md
new file mode 100644
index 00000000000..393ba82b3cd
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/truncate.md
@@ -0,0 +1,22 @@
+---
+sidebar_position: 52
+sidebar_label: TRUNCATE
+---
+
+# TRUNCATE Statement {#truncate-statement}
+
+``` sql
+TRUNCATE TABLE [IF EXISTS] [db.]name [ON CLUSTER cluster]
+```
+
+Removes all data from a table. When the clause `IF EXISTS` is omitted, the query returns an error if the table does not exist.
+
+The `TRUNCATE` query is not supported for [View](../../engines/table-engines/special/view.md), [File](../../engines/table-engines/special/file.md), [URL](../../engines/table-engines/special/url.md), [Buffer](../../engines/table-engines/special/buffer.md) and [Null](../../engines/table-engines/special/null.md) table engines.
+
+You can use the [replication_alter_partitions_sync](../../operations/settings/settings.md#replication-alter-partitions-sync) setting to set up waiting for actions to be executed on replicas.
+
+You can specify how long (in seconds) to wait for inactive replicas to execute `TRUNCATE` queries with the [replication_wait_for_inactive_replica_timeout](../../operations/settings/settings.md#replication-wait-for-inactive-replica-timeout) setting.
+
+:::note    
+If the `replication_alter_partitions_sync` is set to `2` and some replicas are not active for more than the time, specified by the `replication_wait_for_inactive_replica_timeout` setting, then an exception `UNFINISHED` is thrown.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/statements/use.md b/docs/en/reference/sql-reference/statements/use.md
new file mode 100644
index 00000000000..869bf44fdeb
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/use.md
@@ -0,0 +1,16 @@
+---
+sidebar_position: 53
+sidebar_label: USE
+---
+
+# USE Statement {#use}
+
+``` sql
+USE db
+```
+
+Lets you set the current database for the session.
+
+The current database is used for searching for tables if the database is not explicitly defined in the query with a dot before the table name.
+
+This query can’t be made when using the HTTP protocol, since there is no concept of a session.
diff --git a/docs/en/reference/sql-reference/statements/watch.md b/docs/en/reference/sql-reference/statements/watch.md
new file mode 100644
index 00000000000..688cf21e23c
--- /dev/null
+++ b/docs/en/reference/sql-reference/statements/watch.md
@@ -0,0 +1,109 @@
+---
+sidebar_position: 53
+sidebar_label: WATCH
+---
+
+# WATCH Statement (Experimental) {#watch}
+
+:::warning    
+This is an experimental feature that may change in backwards-incompatible ways in the future releases. Enable live views and `WATCH` query using `set allow_experimental_live_view = 1`.
+:::
+
+``` sql
+WATCH [db.]live_view
+[EVENTS]
+[LIMIT n]
+[FORMAT format]
+```
+
+The `WATCH` query performs continuous data retrieval from a [LIVE VIEW](./create/view.md#live-view) table. Unless the `LIMIT` clause is specified it provides an infinite stream of query results from a [LIVE VIEW](./create/view.md#live-view).
+
+```sql
+WATCH [db.]live_view [EVENTS] [LIMIT n] [FORMAT format]
+```
+
+## Virtual columns {#watch-virtual-columns}
+
+The virtual `_version` column in the query result indicates the current result version.
+
+**Example:**
+
+```sql
+CREATE LIVE VIEW lv WITH REFRESH 5 AS SELECT now();
+WATCH lv;
+```
+
+```bash
+┌───────────────now()─┬─_version─┐
+│ 2021-02-21 09:17:21 │        1 │
+└─────────────────────┴──────────┘
+┌───────────────now()─┬─_version─┐
+│ 2021-02-21 09:17:26 │        2 │
+└─────────────────────┴──────────┘
+┌───────────────now()─┬─_version─┐
+│ 2021-02-21 09:17:31 │        3 │
+└─────────────────────┴──────────┘
+...
+```
+
+By default, the requested data is returned to the client, while in conjunction with [INSERT INTO](../../sql-reference/statements/insert-into.md) it can be forwarded to a different table.
+
+**Example:**
+
+```sql
+INSERT INTO [db.]table WATCH [db.]live_view ...
+```
+
+## EVENTS Clause {#events-clause}
+
+The `EVENTS` clause can be used to obtain a short form of the `WATCH` query where instead of the query result you will just get the latest query result version.
+
+```sql
+WATCH [db.]live_view EVENTS;
+```
+
+**Example:**
+
+```sql
+CREATE LIVE VIEW lv WITH REFRESH 5 AS SELECT now();
+WATCH lv EVENTS;
+```
+
+```bash
+┌─version─┐
+│       1 │
+└─────────┘
+┌─version─┐
+│       2 │
+└─────────┘
+...
+```
+
+## LIMIT Clause {#limit-clause}
+
+The `LIMIT n` clause specifies the number of updates the `WATCH` query should wait for before terminating. By default there is no limit on the number of updates and therefore the query will not terminate. The value of `0` indicates that the `WATCH` query should not wait for any new query results and therefore will return immediately once query result is evaluated.
+
+```sql
+WATCH [db.]live_view LIMIT 1;
+```
+
+**Example:**
+
+```sql
+CREATE LIVE VIEW lv WITH REFRESH 5 AS SELECT now();
+WATCH lv EVENTS LIMIT 1;
+```
+
+```bash
+┌─version─┐
+│       1 │
+└─────────┘
+```
+
+## FORMAT Clause {#format-clause}
+
+The `FORMAT` clause works the same way as for the [SELECT](../../sql-reference/statements/select/format.md#format-clause).
+
+:::note    
+The [JSONEachRowWithProgress](../../interfaces/formats.md#jsoneachrowwithprogress) format should be used when watching [LIVE VIEW](./create/view.md#live-view) tables over the HTTP interface. The progress messages will be added to the output to keep the long-lived HTTP connection alive until the query result changes. The interval between progress messages is controlled using the [live_view_heartbeat_interval](./create/view.md#live-view-settings) setting.
+:::
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/syntax.md b/docs/en/reference/sql-reference/syntax.md
new file mode 100644
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--- /dev/null
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@@ -0,0 +1,208 @@
+---
+sidebar_position: 31
+sidebar_label: Syntax
+---
+
+# Syntax {#syntax}
+
+There are two types of parsers in the system: the full SQL parser (a recursive descent parser), and the data format parser (a fast stream parser).
+In all cases except the `INSERT` query, only the full SQL parser is used.
+The `INSERT` query uses both parsers:
+
+``` sql
+INSERT INTO t VALUES (1, 'Hello, world'), (2, 'abc'), (3, 'def')
+```
+
+The `INSERT INTO t VALUES` fragment is parsed by the full parser, and the data `(1, 'Hello, world'), (2, 'abc'), (3, 'def')` is parsed by the fast stream parser. You can also turn on the full parser for the data by using the [input_format_values_interpret_expressions](../operations/settings/settings.md#settings-input_format_values_interpret_expressions) setting. When `input_format_values_interpret_expressions = 1`, ClickHouse first tries to parse values with the fast stream parser. If it fails, ClickHouse tries to use the full parser for the data, treating it like an SQL [expression](#syntax-expressions).
+
+Data can have any format. When a query is received, the server calculates no more than [max_query_size](../operations/settings/settings.md#settings-max_query_size) bytes of the request in RAM (by default, 1 MB), and the rest is stream parsed.
+It allows for avoiding issues with large `INSERT` queries.
+
+When using the `Values` format in an `INSERT` query, it may seem that data is parsed the same as expressions in a `SELECT` query, but this is not true. The `Values` format is much more limited.
+
+The rest of this article covers the full parser. For more information about format parsers, see the [Formats](../interfaces/formats.md) section.
+
+## Spaces {#spaces}
+
+There may be any number of space symbols between syntactical constructions (including the beginning and end of a query). Space symbols include the space, tab, line feed, CR, and form feed.
+
+## Comments {#comments}
+
+ClickHouse supports either SQL-style and C-style comments:
+
+-   SQL-style comments start with `--`, `#!` or `# ` and continue to the end of the line, a space after `--` and `#!` can be omitted.
+-   C-style are from `/*` to `*/`and can be multiline, spaces are not required either.
+
+## Keywords {#syntax-keywords}
+
+Keywords are case-insensitive when they correspond to:
+
+-   SQL standard. For example, `SELECT`, `select` and `SeLeCt` are all valid.
+-   Implementation in some popular DBMS (MySQL or Postgres). For example, `DateTime` is the same as `datetime`.
+
+You can check whether a data type name is case-sensitive in the [system.data_type_families](../operations/system-tables/data_type_families.md#system_tables-data_type_families) table.
+
+In contrast to standard SQL, all other keywords (including functions names) are **case-sensitive**.
+
+Keywords are not reserved; they are treated as such only in the corresponding context. If you use [identifiers](#syntax-identifiers) with the same name as the keywords, enclose them into double-quotes or backticks. For example, the query `SELECT "FROM" FROM table_name` is valid if the table `table_name` has column with the name `"FROM"`.
+
+## Identifiers {#syntax-identifiers}
+
+Identifiers are:
+
+-   Cluster, database, table, partition, and column names.
+-   Functions.
+-   Data types.
+-   [Expression aliases](#syntax-expression_aliases).
+
+Identifiers can be quoted or non-quoted. The latter is preferred.
+
+Non-quoted identifiers must match the regex `^[a-zA-Z_][0-9a-zA-Z_]*$` and can not be equal to [keywords](#syntax-keywords). Examples: `x`, `_1`, `X_y__Z123_`.
+
+If you want to use identifiers the same as keywords or you want to use other symbols in identifiers, quote it using double quotes or backticks, for example, `"id"`, `` `id` ``.
+
+## Literals {#literals}
+
+There are numeric, string, compound, and `NULL` literals.
+
+### Numeric {#numeric}
+
+Numeric literal tries to be parsed:
+
+-   First, as a 64-bit signed number, using the [strtoull](https://en.cppreference.com/w/cpp/string/byte/strtoul) function.
+-   If unsuccessful, as a 64-bit unsigned number, using the [strtoll](https://en.cppreference.com/w/cpp/string/byte/strtol) function.
+-   If unsuccessful, as a floating-point number using the [strtod](https://en.cppreference.com/w/cpp/string/byte/strtof) function.
+-   Otherwise, it returns an error.
+
+Literal value has the smallest type that the value fits in.
+For example, 1 is parsed as `UInt8`, but 256 is parsed as `UInt16`. For more information, see [Data types](../sql-reference/data-types/index.md).
+
+Examples: `1`, `18446744073709551615`, `0xDEADBEEF`, `01`, `0.1`, `1e100`, `-1e-100`, `inf`, `nan`.
+
+### String {#syntax-string-literal}
+
+Only string literals in single quotes are supported. The enclosed characters can be backslash-escaped. The following escape sequences have a corresponding special value: `\b`, `\f`, `\r`, `\n`, `\t`, `\0`, `\a`, `\v`, `\xHH`. In all other cases, escape sequences in the format `\c`, where `c` is any character, are converted to `c`. It means that you can use the sequences `\'`and`\\`. The value will have the [String](../sql-reference/data-types/string.md) type.
+
+In string literals, you need to escape at least `'` and `\`. Single quotes can be escaped with the single quote, literals `'It\'s'` and `'It''s'` are equal.
+
+### Compound {#compound}
+
+Arrays are constructed with square brackets `[1, 2, 3]`. Tuples are constructed with round brackets `(1, 'Hello, world!', 2)`.
+Technically these are not literals, but expressions with the array creation operator and the tuple creation operator, respectively.
+An array must consist of at least one item, and a tuple must have at least two items.
+There’s a separate case when tuples appear in the `IN` clause of a `SELECT` query. Query results can include tuples, but tuples can’t be saved to a database (except of tables with [Memory](../engines/table-engines/special/memory.md) engine).
+
+### NULL {#null-literal}
+
+Indicates that the value is missing.
+
+In order to store `NULL` in a table field, it must be of the [Nullable](../sql-reference/data-types/nullable.md) type.
+
+Depending on the data format (input or output), `NULL` may have a different representation. For more information, see the documentation for [data formats](../interfaces/formats.md#formats).
+
+There are many nuances to processing `NULL`. For example, if at least one of the arguments of a comparison operation is `NULL`, the result of this operation is also `NULL`. The same is true for multiplication, addition, and other operations. For more information, read the documentation for each operation.
+
+In queries, you can check `NULL` using the [IS NULL](../sql-reference/operators/index.md#operator-is-null) and [IS NOT NULL](../sql-reference/operators/index.md) operators and the related functions `isNull` and `isNotNull`.
+
+### Heredoc {#heredeoc}
+
+A [heredoc](https://en.wikipedia.org/wiki/Here_document) is a way to define a string (often multiline), while maintaining the original formatting. A heredoc is defined as a custom string literal, placed between two `$` symbols, for example `$heredoc$`. A value between two heredocs is processed "as-is".
+
+You can use a heredoc to embed snippets of SQL, HTML, or XML code, etc.
+
+**Example**
+
+Query:
+
+```sql
+SELECT $smth$SHOW CREATE VIEW my_view$smth$;
+```
+
+Result:
+
+```text
+┌─'SHOW CREATE VIEW my_view'─┐
+│ SHOW CREATE VIEW my_view   │
+└────────────────────────────┘
+```
+
+## Functions {#functions}
+
+Function calls are written like an identifier with a list of arguments (possibly empty) in round brackets. In contrast to standard SQL, the brackets are required, even for an empty argument list. Example: `now()`.
+There are regular and aggregate functions (see the section “Aggregate functions”). Some aggregate functions can contain two lists of arguments in brackets. Example: `quantile (0.9) (x)`. These aggregate functions are called “parametric” functions, and the arguments in the first list are called “parameters”. The syntax of aggregate functions without parameters is the same as for regular functions.
+
+## Operators {#operators}
+
+Operators are converted to their corresponding functions during query parsing, taking their priority and associativity into account.
+For example, the expression `1 + 2 * 3 + 4` is transformed to `plus(plus(1, multiply(2, 3)), 4)`.
+
+## Data Types and Database Table Engines {#data_types-and-database-table-engines}
+
+Data types and table engines in the `CREATE` query are written the same way as identifiers or functions. In other words, they may or may not contain an argument list in brackets. For more information, see the sections “Data types,” “Table engines,” and “CREATE”.
+
+## Expression Aliases {#syntax-expression_aliases}
+
+An alias is a user-defined name for expression in a query.
+
+``` sql
+expr AS alias
+```
+
+-   `AS` — The keyword for defining aliases. You can define the alias for a table name or a column name in a `SELECT` clause without using the `AS` keyword.
+
+        For example, `SELECT table_name_alias.column_name FROM table_name table_name_alias`.
+
+        In the [CAST](sql_reference/functions/type_conversion_functions.md#type_conversion_function-cast) function, the `AS` keyword has another meaning. See the description of the function.
+
+-   `expr` — Any expression supported by ClickHouse.
+
+        For example, `SELECT column_name * 2 AS double FROM some_table`.
+
+-   `alias` — Name for `expr`. Aliases should comply with the [identifiers](#syntax-identifiers) syntax.
+
+        For example, `SELECT "table t".column_name FROM table_name AS "table t"`.
+
+### Notes on Usage {#notes-on-usage}
+
+Aliases are global for a query or subquery, and you can define an alias in any part of a query for any expression. For example, `SELECT (1 AS n) + 2, n`.
+
+Aliases are not visible in subqueries and between subqueries. For example, while executing the query `SELECT (SELECT sum(b.a) + num FROM b) - a.a AS num FROM a` ClickHouse generates the exception `Unknown identifier: num`.
+
+If an alias is defined for the result columns in the `SELECT` clause of a subquery, these columns are visible in the outer query. For example, `SELECT n + m FROM (SELECT 1 AS n, 2 AS m)`.
+
+Be careful with aliases that are the same as column or table names. Let’s consider the following example:
+
+``` sql
+CREATE TABLE t
+(
+    a Int,
+    b Int
+)
+ENGINE = TinyLog()
+```
+
+``` sql
+SELECT
+    argMax(a, b),
+    sum(b) AS b
+FROM t
+```
+
+``` text
+Received exception from server (version 18.14.17):
+Code: 184. DB::Exception: Received from localhost:9000, 127.0.0.1. DB::Exception: Aggregate function sum(b) is found inside another aggregate function in query.
+```
+
+In this example, we declared table `t` with column `b`. Then, when selecting data, we defined the `sum(b) AS b` alias. As aliases are global, ClickHouse substituted the literal `b` in the expression `argMax(a, b)` with the expression `sum(b)`. This substitution caused the exception. You can change this default behavior by setting [prefer_column_name_to_alias](../operations/settings/settings.md#prefer_column_name_to_alias) to `1`.
+
+## Asterisk {#asterisk}
+
+In a `SELECT` query, an asterisk can replace the expression. For more information, see the section “SELECT”.
+
+## Expressions {#syntax-expressions}
+
+An expression is a function, identifier, literal, application of an operator, expression in brackets, subquery, or asterisk. It can also contain an alias.
+A list of expressions is one or more expressions separated by commas.
+Functions and operators, in turn, can have expressions as arguments.
+
+[Original article](https://clickhouse.com/docs/en/sql_reference/syntax/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/table-functions/cluster.md b/docs/en/reference/sql-reference/table-functions/cluster.md
new file mode 100644
index 00000000000..5954ed1b439
--- /dev/null
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@@ -0,0 +1,59 @@
+---
+sidebar_position: 50
+sidebar_label: cluster
+---
+
+# cluster, clusterAllReplicas {#cluster-clusterallreplicas}
+
+Allows to access all shards in an existing cluster which configured in `remote_servers` section without creating a [Distributed](../../engines/table-engines/special/distributed.md) table. One replica of each shard is queried.
+
+`clusterAllReplicas` function — same as `cluster`, but all replicas are queried. Each replica in a cluster is used as a separate shard/connection.
+
+:::note    
+All available clusters are listed in the [system.clusters](../../operations/system-tables/clusters.md) table.
+:::
+
+**Syntax**
+
+``` sql
+cluster('cluster_name', db.table[, sharding_key])
+cluster('cluster_name', db, table[, sharding_key])
+clusterAllReplicas('cluster_name', db.table[, sharding_key])
+clusterAllReplicas('cluster_name', db, table[, sharding_key])
+```
+**Arguments**
+
+- `cluster_name` – Name of a cluster that is used to build a set of addresses and connection parameters to remote and local servers. 
+- `db.table` or `db`, `table` - Name of a database and a table.  
+- `sharding_key` -  A sharding key. Optional. Needs to be specified if the cluster has more than one shard. 
+
+**Returned value**
+
+The dataset from clusters.
+
+**Using Macros**
+
+`cluster_name` can contain macros — substitution in curly brackets. The substituted value is taken from the [macros](../../operations/server-configuration-parameters/settings.md#macros) section of the server configuration file.
+
+Example:
+
+```sql
+SELECT * FROM cluster('{cluster}', default.example_table);
+```
+
+**Usage and Recommendations**
+
+Using the `cluster` and `clusterAllReplicas` table functions are less efficient than creating a `Distributed` table because in this case, the server connection is re-established for every request. When processing a large number of queries, please always create the `Distributed` table ahead of time, and do not use the `cluster` and `clusterAllReplicas` table functions.
+
+The `cluster` and `clusterAllReplicas` table functions can be useful in the following cases:
+
+-   Accessing a specific cluster for data comparison, debugging, and testing.
+-   Queries to various ClickHouse clusters and replicas for research purposes.
+-   Infrequent distributed requests that are made manually.
+
+Connection settings like `host`, `port`, `user`, `password`, `compression`, `secure` are taken from `<remote_servers>` config section. See details in [Distributed engine](../../engines/table-engines/special/distributed.md).
+
+**See Also**
+
+-   [skip_unavailable_shards](../../operations/settings/settings.md#settings-skip_unavailable_shards)
+-   [load_balancing](../../operations/settings/settings.md#settings-load_balancing)
diff --git a/docs/en/reference/sql-reference/table-functions/dictionary.md b/docs/en/reference/sql-reference/table-functions/dictionary.md
new file mode 100644
index 00000000000..f04a4b6eb24
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/dictionary.md
@@ -0,0 +1,59 @@
+---
+sidebar_position: 54
+sidebar_label: dictionary function
+---
+
+# dictionary {#dictionary-function}
+
+Displays the [dictionary](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md) data as a ClickHouse table. Works the same way as [Dictionary](../../engines/table-engines/special/dictionary.md) engine.
+
+**Syntax**
+
+``` sql
+dictionary('dict')
+```
+
+**Arguments**
+
+-   `dict` — A dictionary name. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+A ClickHouse table.
+
+**Example**
+
+Input table `dictionary_source_table`:
+
+``` text
+┌─id─┬─value─┐
+│  0 │     0 │
+│  1 │     1 │
+└────┴───────┘
+```
+
+Create a dictionary:
+
+``` sql
+CREATE DICTIONARY new_dictionary(id UInt64, value UInt64 DEFAULT 0) PRIMARY KEY id
+SOURCE(CLICKHOUSE(HOST 'localhost' PORT tcpPort() USER 'default' TABLE 'dictionary_source_table')) LAYOUT(DIRECT());
+```
+
+Query:
+
+``` sql
+SELECT * FROM dictionary('new_dictionary');
+```
+
+Result:
+
+``` text
+┌─id─┬─value─┐
+│  0 │     0 │
+│  1 │     1 │
+└────┴───────┘
+```
+
+**See Also**
+
+-   [Dictionary engine](../../engines/table-engines/special/dictionary.md#dictionary)
diff --git a/docs/en/reference/sql-reference/table-functions/file.md b/docs/en/reference/sql-reference/table-functions/file.md
new file mode 100644
index 00000000000..4b72b0d84f5
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/file.md
@@ -0,0 +1,130 @@
+---
+sidebar_position: 37
+sidebar_label: file
+---
+
+# file {#file}
+
+Creates a table from a file. This table function is similar to [url](../../sql-reference/table-functions/url.md) and [hdfs](../../sql-reference/table-functions/hdfs.md) ones.
+
+`file` function can be used in `SELECT` and `INSERT` queries on data in [File](../../engines/table-engines/special/file.md) tables.
+
+**Syntax**
+
+``` sql
+file(path, format, structure)
+```
+
+**Parameters**
+
+-   `path` — The relative path to the file from [user_files_path](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-user_files_path). Path to file support following globs in read-only mode: `*`, `?`, `{abc,def}` and `{N..M}` where `N`, `M` — numbers, `'abc', 'def'` — strings.
+-   `format` — The [format](../../interfaces/formats.md#formats) of the file.
+-   `structure` — Structure of the table. Format: `'column1_name column1_type, column2_name column2_type, ...'`.
+
+**Returned value**
+
+A table with the specified structure for reading or writing data in the specified file.
+
+**Examples**
+
+Setting `user_files_path` and the contents of the file `test.csv`:
+
+``` bash
+$ grep user_files_path /etc/clickhouse-server/config.xml
+    <user_files_path>/var/lib/clickhouse/user_files/</user_files_path>
+
+$ cat /var/lib/clickhouse/user_files/test.csv
+    1,2,3
+    3,2,1
+    78,43,45
+```
+
+Getting data from a table in `test.csv` and selecting the first two rows from it:
+
+``` sql
+SELECT * FROM file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32') LIMIT 2;
+```
+
+``` text
+┌─column1─┬─column2─┬─column3─┐
+│       1 │       2 │       3 │
+│       3 │       2 │       1 │
+└─────────┴─────────┴─────────┘
+```
+
+Getting the first 10 lines of a table that contains 3 columns of [UInt32](../../sql-reference/data-types/int-uint.md) type from a CSV file:
+
+``` sql
+SELECT * FROM file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32') LIMIT 10;
+```
+
+Inserting data from a file into a table:
+
+``` sql
+INSERT INTO FUNCTION file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32') VALUES (1, 2, 3), (3, 2, 1);
+SELECT * FROM file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32');
+```
+
+``` text
+┌─column1─┬─column2─┬─column3─┐
+│       1 │       2 │       3 │
+│       3 │       2 │       1 │
+└─────────┴─────────┴─────────┘
+```
+
+## Globs in Path {#globs-in-path}
+
+Multiple path components can have globs. For being processed file must exist and match to the whole path pattern (not only suffix or prefix).
+
+-   `*` — Substitutes any number of any characters except `/` including empty string.
+-   `?` — Substitutes any single character.
+-   `{some_string,another_string,yet_another_one}` — Substitutes any of strings `'some_string', 'another_string', 'yet_another_one'`.
+-   `{N..M}` — Substitutes any number in range from N to M including both borders.
+
+Constructions with `{}` are similar to the [remote](remote.md) table function.
+
+**Example**
+
+Suppose we have several files with the following relative paths:
+
+-   'some_dir/some_file_1'
+-   'some_dir/some_file_2'
+-   'some_dir/some_file_3'
+-   'another_dir/some_file_1'
+-   'another_dir/some_file_2'
+-   'another_dir/some_file_3'
+
+Query the number of rows in these files:
+
+``` sql
+SELECT count(*) FROM file('{some,another}_dir/some_file_{1..3}', 'TSV', 'name String, value UInt32');
+```
+
+Query the number of rows in all files of these two directories:
+
+``` sql
+SELECT count(*) FROM file('{some,another}_dir/*', 'TSV', 'name String, value UInt32');
+```
+
+:::warning    
+If your listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
+:::
+
+**Example**
+
+Query the data from files named `file000`, `file001`, … , `file999`:
+
+``` sql
+SELECT count(*) FROM file('big_dir/file{0..9}{0..9}{0..9}', 'CSV', 'name String, value UInt32');
+```
+
+## Virtual Columns {#virtual-columns}
+
+-   `_path` — Path to the file.
+-   `_file` — Name of the file.
+
+**See Also**
+
+-   [Virtual columns](../../engines/table-engines/index.md#table_engines-virtual_columns)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/table-functions/file/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/table-functions/generate.md b/docs/en/reference/sql-reference/table-functions/generate.md
new file mode 100644
index 00000000000..bb9ad3f7551
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/generate.md
@@ -0,0 +1,41 @@
+---
+sidebar_position: 47
+sidebar_label: generateRandom
+---
+
+# generateRandom {#generaterandom}
+
+Generates random data with given schema.
+Allows to populate test tables with data.
+Supports all data types that can be stored in table except `LowCardinality` and `AggregateFunction`.
+
+``` sql
+generateRandom('name TypeName[, name TypeName]...', [, 'random_seed'[, 'max_string_length'[, 'max_array_length']]])
+```
+
+**Arguments**
+
+-   `name` — Name of corresponding column.
+-   `TypeName` — Type of corresponding column.
+-   `max_array_length` — Maximum array length for all generated arrays. Defaults to `10`.
+-   `max_string_length` — Maximum string length for all generated strings. Defaults to `10`.
+-   `random_seed` — Specify random seed manually to produce stable results. If NULL — seed is randomly generated.
+
+**Returned Value**
+
+A table object with requested schema.
+
+## Usage Example {#usage-example}
+
+``` sql
+SELECT * FROM generateRandom('a Array(Int8), d Decimal32(4), c Tuple(DateTime64(3), UUID)', 1, 10, 2) LIMIT 3;
+```
+
+``` text
+┌─a────────┬────────────d─┬─c──────────────────────────────────────────────────────────────────┐
+│ [77]     │ -124167.6723 │ ('2061-04-17 21:59:44.573','3f72f405-ec3e-13c8-44ca-66ef335f7835') │
+│ [32,110] │ -141397.7312 │ ('1979-02-09 03:43:48.526','982486d1-5a5d-a308-e525-7bd8b80ffa73') │
+│ [68]     │  -67417.0770 │ ('2080-03-12 14:17:31.269','110425e5-413f-10a6-05ba-fa6b3e929f15') │
+└──────────┴──────────────┴────────────────────────────────────────────────────────────────────┘
+```
+
diff --git a/docs/en/reference/sql-reference/table-functions/hdfs.md b/docs/en/reference/sql-reference/table-functions/hdfs.md
new file mode 100644
index 00000000000..7f7dc53d27e
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/hdfs.md
@@ -0,0 +1,102 @@
+---
+sidebar_position: 45
+sidebar_label: hdfs
+---
+
+# hdfs {#hdfs}
+
+Creates a table from files in HDFS. This table function is similar to [url](../../sql-reference/table-functions/url.md) and [file](../../sql-reference/table-functions/file.md) ones.
+
+``` sql
+hdfs(URI, format, structure)
+```
+
+**Input parameters**
+
+-   `URI` — The relative URI to the file in HDFS. Path to file support following globs in readonly mode: `*`, `?`, `{abc,def}` and `{N..M}` where `N`, `M` — numbers, \``'abc', 'def'` — strings.
+-   `format` — The [format](../../interfaces/formats.md#formats) of the file.
+-   `structure` — Structure of the table. Format `'column1_name column1_type, column2_name column2_type, ...'`.
+
+**Returned value**
+
+A table with the specified structure for reading or writing data in the specified file.
+
+**Example**
+
+Table from `hdfs://hdfs1:9000/test` and selection of the first two rows from it:
+
+``` sql
+SELECT *
+FROM hdfs('hdfs://hdfs1:9000/test', 'TSV', 'column1 UInt32, column2 UInt32, column3 UInt32')
+LIMIT 2
+```
+
+``` text
+┌─column1─┬─column2─┬─column3─┐
+│       1 │       2 │       3 │
+│       3 │       2 │       1 │
+└─────────┴─────────┴─────────┘
+```
+
+**Globs in path**
+
+Multiple path components can have globs. For being processed file should exists and matches to the whole path pattern (not only suffix or prefix).
+
+-   `*` — Substitutes any number of any characters except `/` including empty string.
+-   `?` — Substitutes any single character.
+-   `{some_string,another_string,yet_another_one}` — Substitutes any of strings `'some_string', 'another_string', 'yet_another_one'`.
+-   `{N..M}` — Substitutes any number in range from N to M including both borders.
+
+Constructions with `{}` are similar to the [remote table function](../../sql-reference/table-functions/remote.md)).
+
+**Example**
+
+1.  Suppose that we have several files with following URIs on HDFS:
+
+-   ‘hdfs://hdfs1:9000/some_dir/some_file_1’
+-   ‘hdfs://hdfs1:9000/some_dir/some_file_2’
+-   ‘hdfs://hdfs1:9000/some_dir/some_file_3’
+-   ‘hdfs://hdfs1:9000/another_dir/some_file_1’
+-   ‘hdfs://hdfs1:9000/another_dir/some_file_2’
+-   ‘hdfs://hdfs1:9000/another_dir/some_file_3’
+
+2.  Query the amount of rows in these files:
+
+<!-- -->
+
+``` sql
+SELECT count(*)
+FROM hdfs('hdfs://hdfs1:9000/{some,another}_dir/some_file_{1..3}', 'TSV', 'name String, value UInt32')
+```
+
+3.  Query the amount of rows in all files of these two directories:
+
+<!-- -->
+
+``` sql
+SELECT count(*)
+FROM hdfs('hdfs://hdfs1:9000/{some,another}_dir/*', 'TSV', 'name String, value UInt32')
+```
+
+:::warning    
+If your listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
+:::
+
+**Example**
+
+Query the data from files named `file000`, `file001`, … , `file999`:
+
+``` sql
+SELECT count(*)
+FROM hdfs('hdfs://hdfs1:9000/big_dir/file{0..9}{0..9}{0..9}', 'CSV', 'name String, value UInt32')
+```
+
+## Virtual Columns {#virtual-columns}
+
+-   `_path` — Path to the file.
+-   `_file` — Name of the file.
+
+**See Also**
+
+-   [Virtual columns](../../engines/table-engines/index.md#table_engines-virtual_columns)
+
diff --git a/docs/en/reference/sql-reference/table-functions/hdfsCluster.md b/docs/en/reference/sql-reference/table-functions/hdfsCluster.md
new file mode 100644
index 00000000000..b46b8e64a1a
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/hdfsCluster.md
@@ -0,0 +1,59 @@
+---
+sidebar_position: 55
+sidebar_label: hdfsCluster
+---
+
+# hdfsCluster Table Function {#hdfsCluster-table-function}
+
+Allows processing files from HDFS in parallel from many nodes in a specified cluster. On initiator it creates a connection to all nodes in the cluster, discloses asterics in HDFS file path, and dispatches each file dynamically. On the worker node it asks the initiator about the next task to process and processes it. This is repeated until all tasks are finished.
+
+**Syntax**
+
+``` sql
+hdfsCluster(cluster_name, URI, format, structure)
+```
+
+**Arguments**
+
+-   `cluster_name` — Name of a cluster that is used to build a set of addresses and connection parameters to remote and local servers.
+-   `URI` — URI to a file or a bunch of files. Supports following wildcards in readonly mode: `*`, `?`, `{'abc','def'}` and `{N..M}` where `N`, `M` — numbers, `abc`, `def` — strings. For more information see [Wildcards In Path](../../engines/table-engines/integrations/s3.md#wildcards-in-path).
+-   `format` — The [format](../../interfaces/formats.md#formats) of the file.
+-   `structure` — Structure of the table. Format `'column1_name column1_type, column2_name column2_type, ...'`.
+
+**Returned value**
+
+A table with the specified structure for reading data in the specified file.
+
+**Examples**
+
+1.  Suppose that we have a ClickHouse cluster named `cluster_simple`, and several files with following URIs on HDFS:
+
+-   ‘hdfs://hdfs1:9000/some_dir/some_file_1’
+-   ‘hdfs://hdfs1:9000/some_dir/some_file_2’
+-   ‘hdfs://hdfs1:9000/some_dir/some_file_3’
+-   ‘hdfs://hdfs1:9000/another_dir/some_file_1’
+-   ‘hdfs://hdfs1:9000/another_dir/some_file_2’
+-   ‘hdfs://hdfs1:9000/another_dir/some_file_3’
+
+2.  Query the amount of rows in these files:
+
+``` sql
+SELECT count(*)
+FROM hdfsCluster('cluster_simple', 'hdfs://hdfs1:9000/{some,another}_dir/some_file_{1..3}', 'TSV', 'name String, value UInt32')
+```
+
+3.  Query the amount of rows in all files of these two directories:
+
+``` sql
+SELECT count(*)
+FROM hdfsCluster('cluster_simple', 'hdfs://hdfs1:9000/{some,another}_dir/*', 'TSV', 'name String, value UInt32')
+```
+
+:::warning    
+If your listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
+:::
+
+**See Also**
+
+-   [HDFS engine](../../engines/table-engines/integrations/hdfs.md)
+-   [HDFS table function](../../sql-reference/table-functions/hdfs.md)
diff --git a/docs/en/reference/sql-reference/table-functions/index.md b/docs/en/reference/sql-reference/table-functions/index.md
new file mode 100644
index 00000000000..a51312324f0
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/index.md
@@ -0,0 +1,41 @@
+---
+sidebar_label: Table Functions
+sidebar_position: 34
+---
+
+# Table Functions 
+
+Table functions are methods for constructing tables.
+
+You can use table functions in:
+
+-   [FROM](../../sql-reference/statements/select/from.md) clause of the `SELECT` query.
+
+        The method for creating a temporary table that is available only in the current query. The table is deleted when the query finishes.
+
+-   [CREATE TABLE AS table_function()](../../sql-reference/statements/create/table.md) query.
+
+        It's one of the methods of creating a table.
+
+-   [INSERT INTO TABLE FUNCTION](../../sql-reference/statements/insert-into.md#inserting-into-table-function) query.
+
+:::warning
+You can’t use table functions if the [allow_ddl](../../operations/settings/permissions-for-queries.md#settings_allow_ddl) setting is disabled.
+:::
+
+| Function                                                         | Description                                                                                                                            |
+|------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------|
+| [file](../../sql-reference/table-functions/file.md)              | Creates a [File](../../engines/table-engines/special/file.md)-engine table.                                                            |
+| [merge](../../sql-reference/table-functions/merge.md)            | Creates a [Merge](../../engines/table-engines/special/merge.md)-engine table.                                                          |
+| [numbers](../../sql-reference/table-functions/numbers.md)        | Creates a table with a single column filled with integer numbers.                                                                      |
+| [remote](../../sql-reference/table-functions/remote.md)          | Allows you to access remote servers without creating a [Distributed](../../engines/table-engines/special/distributed.md)-engine table. |
+| [url](../../sql-reference/table-functions/url.md)                | Creates a [Url](../../engines/table-engines/special/url.md)-engine table.                                                              |
+| [mysql](../../sql-reference/table-functions/mysql.md)            | Creates a [MySQL](../../engines/table-engines/integrations/mysql.md)-engine table.                                                     |
+| [postgresql](../../sql-reference/table-functions/postgresql.md)  | Creates a [PostgreSQL](../../engines/table-engines/integrations/postgresql.md)-engine table.                                           |
+| [jdbc](../../sql-reference/table-functions/jdbc.md)              | Creates a [JDBC](../../engines/table-engines/integrations/jdbc.md)-engine table.                                                       |
+| [odbc](../../sql-reference/table-functions/odbc.md)              | Creates a [ODBC](../../engines/table-engines/integrations/odbc.md)-engine table.                                                       |
+| [hdfs](../../sql-reference/table-functions/hdfs.md)              | Creates a [HDFS](../../engines/table-engines/integrations/hdfs.md)-engine table.                                                       |
+| [s3](../../sql-reference/table-functions/s3.md)                  | Creates a [S3](../../engines/table-engines/integrations/s3.md)-engine table.                                                           |
+| [sqlite](../../sql-reference/table-functions/sqlite.md)          | Creates a [sqlite](../../engines/table-engines/integrations/sqlite.md)-engine table.                                                       |
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/table-functions/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/table-functions/input.md b/docs/en/reference/sql-reference/table-functions/input.md
new file mode 100644
index 00000000000..916abb890ff
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/input.md
@@ -0,0 +1,44 @@
+---
+sidebar_position: 46
+sidebar_label: input
+---
+
+# input {#input}
+
+`input(structure)` - table function that allows effectively convert and insert data sent to the
+server with given structure to the table with another structure.
+
+`structure` - structure of data sent to the server in following format `'column1_name column1_type, column2_name column2_type, ...'`.
+For example, `'id UInt32, name String'`.
+
+This function can be used only in `INSERT SELECT` query and only once but otherwise behaves like ordinary table function
+(for example, it can be used in subquery, etc.).
+
+Data can be sent in any way like for ordinary `INSERT` query and passed in any available [format](../../interfaces/formats.md#formats)
+that must be specified in the end of query (unlike ordinary `INSERT SELECT`).
+
+The main feature of this function is that when server receives data from client it simultaneously converts it
+according to the list of expressions in the `SELECT` clause and inserts into the target table. Temporary table
+with all transferred data is not created.
+
+**Examples**
+
+-   Let the `test` table has the following structure `(a String, b String)`
+    and data in `data.csv` has a different structure `(col1 String, col2 Date, col3 Int32)`. Query for insert
+    data from the `data.csv` into the `test` table with simultaneous conversion looks like this:
+
+<!-- -->
+
+``` bash
+$ cat data.csv | clickhouse-client --query="INSERT INTO test SELECT lower(col1), col3 * col3 FROM input('col1 String, col2 Date, col3 Int32') FORMAT CSV";
+```
+
+-   If `data.csv` contains data of the same structure `test_structure` as the table `test` then these two queries are equal:
+
+<!-- -->
+
+``` bash
+$ cat data.csv | clickhouse-client --query="INSERT INTO test FORMAT CSV"
+$ cat data.csv | clickhouse-client --query="INSERT INTO test SELECT * FROM input('test_structure') FORMAT CSV"
+```
+
diff --git a/docs/en/reference/sql-reference/table-functions/jdbc.md b/docs/en/reference/sql-reference/table-functions/jdbc.md
new file mode 100644
index 00000000000..57128f7d146
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/jdbc.md
@@ -0,0 +1,38 @@
+---
+sidebar_position: 43
+sidebar_label: jdbc
+---
+
+# jdbc {#table-function-jdbc}
+
+`jdbc(datasource, schema, table)` - returns table that is connected via JDBC driver.
+
+This table function requires separate [clickhouse-jdbc-bridge](https://github.com/ClickHouse/clickhouse-jdbc-bridge) program to be running.
+It supports Nullable types (based on DDL of remote table that is queried).
+
+**Examples**
+
+``` sql
+SELECT * FROM jdbc('jdbc:mysql://localhost:3306/?user=root&password=root', 'schema', 'table')
+```
+
+``` sql
+SELECT * FROM jdbc('mysql://localhost:3306/?user=root&password=root', 'select * from schema.table')
+```
+
+``` sql
+SELECT * FROM jdbc('mysql-dev?p1=233', 'num Int32', 'select toInt32OrZero(''{{p1}}'') as num')
+```
+
+``` sql
+SELECT *
+FROM jdbc('mysql-dev?p1=233', 'num Int32', 'select toInt32OrZero(''{{p1}}'') as num')
+```
+
+``` sql
+SELECT a.datasource AS server1, b.datasource AS server2, b.name AS db
+FROM jdbc('mysql-dev?datasource_column', 'show databases') a
+INNER JOIN jdbc('self?datasource_column', 'show databases') b ON a.Database = b.name
+```
+
+[Original article](https://clickhouse.com/docs/en/query_language/table_functions/jdbc/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/table-functions/merge.md b/docs/en/reference/sql-reference/table-functions/merge.md
new file mode 100644
index 00000000000..301f0a69caf
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/merge.md
@@ -0,0 +1,27 @@
+---
+sidebar_position: 38
+sidebar_label: merge
+---
+
+# merge {#merge}
+
+Creates a temporary [Merge](../../engines/table-engines/special/merge.md) table. The table structure is taken from the first table encountered that matches the regular expression.
+
+**Syntax**
+
+```sql
+merge('db_name', 'tables_regexp')
+```
+**Arguments**
+
+- `db_name` — Possible values:
+    - database name, 
+    - constant expression that returns a string with a database name, for example, `currentDatabase()`,
+    - `REGEXP(expression)`, where `expression` is a regular expression to match the DB names.
+
+- `tables_regexp` — A regular expression to match the table names in the specified DB or DBs.
+
+**See Also**
+
+-   [Merge](../../engines/table-engines/special/merge.md) table engine
+
diff --git a/docs/en/reference/sql-reference/table-functions/mysql.md b/docs/en/reference/sql-reference/table-functions/mysql.md
new file mode 100644
index 00000000000..c6983d8fba1
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/mysql.md
@@ -0,0 +1,114 @@
+---
+sidebar_position: 42
+sidebar_label: mysql
+---
+
+# mysql {#mysql}
+
+Allows `SELECT` and `INSERT` queries to be performed on data that is stored on a remote MySQL server.
+
+**Syntax**
+
+``` sql
+mysql('host:port', 'database', 'table', 'user', 'password'[, replace_query, 'on_duplicate_clause'])
+```
+
+**Arguments**
+
+-   `host:port` — MySQL server address.
+
+-   `database` — Remote database name.
+
+-   `table` — Remote table name.
+
+-   `user` — MySQL user.
+
+-   `password` — User password.
+
+-   `replace_query` — Flag that converts `INSERT INTO` queries to `REPLACE INTO`. Possible values:
+    - `0` - The query is executed as `INSERT INTO`.
+    - `1` - The query is executed as `REPLACE INTO`.
+
+-   `on_duplicate_clause` — The `ON DUPLICATE KEY on_duplicate_clause` expression that is added to the `INSERT` query. Can be specified only with `replace_query = 0` (if you simultaneously pass `replace_query = 1` and `on_duplicate_clause`, ClickHouse generates an exception).
+
+    Example: `INSERT INTO t (c1,c2) VALUES ('a', 2) ON DUPLICATE KEY UPDATE c2 = c2 + 1;`
+
+    `on_duplicate_clause` here is `UPDATE c2 = c2 + 1`. See the MySQL documentation to find which `on_duplicate_clause` you can use with the `ON DUPLICATE KEY` clause.
+
+Simple `WHERE` clauses such as `=, !=, >, >=, <, <=` are currently executed on the MySQL server.
+
+The rest of the conditions and the `LIMIT` sampling constraint are executed in ClickHouse only after the query to MySQL finishes.
+
+Supports multiple replicas that must be listed by `|`. For example:
+
+```sql
+SELECT name FROM mysql(`mysql{1|2|3}:3306`, 'mysql_database', 'mysql_table', 'user', 'password');
+```
+
+or
+
+```sql
+SELECT name FROM mysql(`mysql1:3306|mysql2:3306|mysql3:3306`, 'mysql_database', 'mysql_table', 'user', 'password');
+```
+
+**Returned Value**
+
+A table object with the same columns as the original MySQL table.
+
+:::note    
+In the `INSERT` query to distinguish table function `mysql(...)` from table name with column names list, you must use keywords `FUNCTION` or `TABLE FUNCTION`. See examples below.
+:::
+
+**Examples**
+
+Table in MySQL:
+
+``` text
+mysql> CREATE TABLE `test`.`test` (
+    ->   `int_id` INT NOT NULL AUTO_INCREMENT,
+    ->   `float` FLOAT NOT NULL,
+    ->   PRIMARY KEY (`int_id`));
+
+mysql> INSERT INTO test (`int_id`, `float`) VALUES (1,2);
+
+mysql> SELECT * FROM test;
++--------+-------+
+| int_id | float |
++--------+-------+
+|      1 |     2 |
++--------+-------+
+```
+
+Selecting data from ClickHouse:
+
+``` sql
+SELECT * FROM mysql('localhost:3306', 'test', 'test', 'bayonet', '123');
+```
+
+``` text
+┌─int_id─┬─float─┐
+│      1 │     2 │
+└────────┴───────┘
+```
+
+Replacing and inserting:
+
+```sql
+INSERT INTO FUNCTION mysql('localhost:3306', 'test', 'test', 'bayonet', '123', 1) (int_id, float) VALUES (1, 3);
+INSERT INTO TABLE FUNCTION mysql('localhost:3306', 'test', 'test', 'bayonet', '123', 0, 'UPDATE int_id = int_id + 1') (int_id, float) VALUES (1, 4);
+SELECT * FROM mysql('localhost:3306', 'test', 'test', 'bayonet', '123');
+```
+
+``` text
+┌─int_id─┬─float─┐
+│      1 │     3 │
+│      2 │     4 │
+└────────┴───────┘
+```
+
+**See Also**
+
+-   [The ‘MySQL’ table engine](../../engines/table-engines/integrations/mysql.md)
+-   [Using MySQL as a source of external dictionary](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-mysql)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/table_functions/mysql/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/table-functions/null.md b/docs/en/reference/sql-reference/table-functions/null.md
new file mode 100644
index 00000000000..48df12bfece
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/null.md
@@ -0,0 +1,43 @@
+---
+sidebar_position: 53
+sidebar_label: null function
+---
+
+# null {#null-function}
+
+Creates a temporary table of the specified structure with the [Null](../../engines/table-engines/special/null.md) table engine. According to the `Null`-engine properties, the table data is ignored and the table itself is immediately droped right after the query execution. The function is used for the convenience of test writing and demonstrations.
+
+**Syntax**
+
+``` sql
+null('structure')
+```
+
+**Parameter**
+
+-   `structure` — A list of columns and column types. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+A temporary `Null`-engine table with the specified structure.
+
+**Example**
+
+Query with the `null` function:
+
+``` sql
+INSERT INTO function null('x UInt64') SELECT * FROM numbers_mt(1000000000);
+```
+can replace three queries:
+
+```sql
+CREATE TABLE t (x UInt64) ENGINE = Null;
+INSERT INTO t SELECT * FROM numbers_mt(1000000000);
+DROP TABLE IF EXISTS t;
+```
+
+See also:
+
+-   [Null table engine](../../engines/table-engines/special/null.md)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/table-functions/null/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/table-functions/numbers.md b/docs/en/reference/sql-reference/table-functions/numbers.md
new file mode 100644
index 00000000000..c15c47cf725
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/numbers.md
@@ -0,0 +1,27 @@
+---
+sidebar_position: 39
+sidebar_label: numbers
+---
+
+# numbers {#numbers}
+
+`numbers(N)` – Returns a table with the single ‘number’ column (UInt64) that contains integers from 0 to N-1.
+`numbers(N, M)` - Returns a table with the single ‘number’ column (UInt64) that contains integers from N to (N + M - 1).
+
+Similar to the `system.numbers` table, it can be used for testing and generating successive values, `numbers(N, M)` more efficient than `system.numbers`.
+
+The following queries are equivalent:
+
+``` sql
+SELECT * FROM numbers(10);
+SELECT * FROM numbers(0, 10);
+SELECT * FROM system.numbers LIMIT 10;
+```
+
+Examples:
+
+``` sql
+-- Generate a sequence of dates from 2010-01-01 to 2010-12-31
+select toDate('2010-01-01') + number as d FROM numbers(365);
+```
+
diff --git a/docs/en/reference/sql-reference/table-functions/odbc.md b/docs/en/reference/sql-reference/table-functions/odbc.md
new file mode 100644
index 00000000000..d2614337cdd
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/odbc.md
@@ -0,0 +1,104 @@
+---
+sidebar_position: 44
+sidebar_label: odbc
+---
+
+# odbc {#table-functions-odbc}
+
+Returns table that is connected via [ODBC](https://en.wikipedia.org/wiki/Open_Database_Connectivity).
+
+``` sql
+odbc(connection_settings, external_database, external_table)
+```
+
+Parameters:
+
+-   `connection_settings` — Name of the section with connection settings in the `odbc.ini` file.
+-   `external_database` — Name of a database in an external DBMS.
+-   `external_table` — Name of a table in the `external_database`.
+
+To safely implement ODBC connections, ClickHouse uses a separate program `clickhouse-odbc-bridge`. If the ODBC driver is loaded directly from `clickhouse-server`, driver problems can crash the ClickHouse server. ClickHouse automatically starts `clickhouse-odbc-bridge` when it is required. The ODBC bridge program is installed from the same package as the `clickhouse-server`.
+
+The fields with the `NULL` values from the external table are converted into the default values for the base data type. For example, if a remote MySQL table field has the `INT NULL` type it is converted to 0 (the default value for ClickHouse `Int32` data type).
+
+## Usage Example {#usage-example}
+
+**Getting data from the local MySQL installation via ODBC**
+
+This example is checked for Ubuntu Linux 18.04 and MySQL server 5.7.
+
+Ensure that unixODBC and MySQL Connector are installed.
+
+By default (if installed from packages), ClickHouse starts as user `clickhouse`. Thus you need to create and configure this user in the MySQL server.
+
+``` bash
+$ sudo mysql
+```
+
+``` sql
+mysql> CREATE USER 'clickhouse'@'localhost' IDENTIFIED BY 'clickhouse';
+mysql> GRANT ALL PRIVILEGES ON *.* TO 'clickhouse'@'clickhouse' WITH GRANT OPTION;
+```
+
+Then configure the connection in `/etc/odbc.ini`.
+
+``` bash
+$ cat /etc/odbc.ini
+[mysqlconn]
+DRIVER = /usr/local/lib/libmyodbc5w.so
+SERVER = 127.0.0.1
+PORT = 3306
+DATABASE = test
+USERNAME = clickhouse
+PASSWORD = clickhouse
+```
+
+You can check the connection using the `isql` utility from the unixODBC installation.
+
+``` bash
+$ isql -v mysqlconn
++-------------------------+
+| Connected!                            |
+|                                       |
+...
+```
+
+Table in MySQL:
+
+``` text
+mysql> CREATE TABLE `test`.`test` (
+    ->   `int_id` INT NOT NULL AUTO_INCREMENT,
+    ->   `int_nullable` INT NULL DEFAULT NULL,
+    ->   `float` FLOAT NOT NULL,
+    ->   `float_nullable` FLOAT NULL DEFAULT NULL,
+    ->   PRIMARY KEY (`int_id`));
+Query OK, 0 rows affected (0,09 sec)
+
+mysql> insert into test (`int_id`, `float`) VALUES (1,2);
+Query OK, 1 row affected (0,00 sec)
+
+mysql> select * from test;
++------+----------+-----+----------+
+| int_id | int_nullable | float | float_nullable |
++------+----------+-----+----------+
+|      1 |         NULL |     2 |           NULL |
++------+----------+-----+----------+
+1 row in set (0,00 sec)
+```
+
+Retrieving data from the MySQL table in ClickHouse:
+
+``` sql
+SELECT * FROM odbc('DSN=mysqlconn', 'test', 'test')
+```
+
+``` text
+┌─int_id─┬─int_nullable─┬─float─┬─float_nullable─┐
+│      1 │            0 │     2 │              0 │
+└────────┴──────────────┴───────┴────────────────┘
+```
+
+## See Also {#see-also}
+
+-   [ODBC external dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-odbc)
+-   [ODBC table engine](../../engines/table-engines/integrations/odbc.md).
diff --git a/docs/en/reference/sql-reference/table-functions/postgresql.md b/docs/en/reference/sql-reference/table-functions/postgresql.md
new file mode 100644
index 00000000000..6a30b1f3f0c
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/postgresql.md
@@ -0,0 +1,134 @@
+---
+sidebar_position: 42
+sidebar_label: postgresql
+---
+
+# postgresql {#postgresql}
+
+Allows `SELECT` and `INSERT` queries to be performed on data that is stored on a remote PostgreSQL server.
+
+**Syntax**
+
+``` sql
+postgresql('host:port', 'database', 'table', 'user', 'password'[, `schema`])
+```
+
+**Arguments**
+
+-   `host:port` — PostgreSQL server address.
+-   `database` — Remote database name.
+-   `table` — Remote table name.
+-   `user` — PostgreSQL user.
+-   `password` — User password.
+-   `schema` — Non-default table schema. Optional.
+
+**Returned Value**
+
+A table object with the same columns as the original PostgreSQL table.
+
+:::note    
+In the `INSERT` query to distinguish table function `postgresql(...)` from table name with column names list you must use keywords `FUNCTION` or `TABLE FUNCTION`. See examples below.
+:::
+
+## Implementation Details {#implementation-details}
+
+`SELECT` queries on PostgreSQL side run as `COPY (SELECT ...) TO STDOUT` inside read-only PostgreSQL transaction with commit after each `SELECT` query.
+
+Simple `WHERE` clauses such as `=`, `!=`, `>`, `>=`, `<`, `<=`, and `IN` are executed on the PostgreSQL server.
+
+All joins, aggregations, sorting, `IN [ array ]` conditions and the `LIMIT` sampling constraint are executed in ClickHouse only after the query to PostgreSQL finishes.
+
+`INSERT` queries on PostgreSQL side run as `COPY "table_name" (field1, field2, ... fieldN) FROM STDIN` inside PostgreSQL transaction with auto-commit after each `INSERT` statement.
+
+PostgreSQL Array types converts into ClickHouse arrays.
+
+:::note    
+Be careful, in PostgreSQL an array data type column like Integer[] may contain arrays of different dimensions in different rows, but in ClickHouse it is only allowed to have multidimensional arrays of the same dimension in all rows.
+:::
+
+Supports multiple replicas that must be listed by `|`. For example:
+
+```sql
+SELECT name FROM postgresql(`postgres{1|2|3}:5432`, 'postgres_database', 'postgres_table', 'user', 'password');
+```
+
+or
+
+```sql
+SELECT name FROM postgresql(`postgres1:5431|postgres2:5432`, 'postgres_database', 'postgres_table', 'user', 'password');
+```
+
+Supports replicas priority for PostgreSQL dictionary source. The bigger the number in map, the less the priority. The highest priority is `0`.
+
+**Examples**
+
+Table in PostgreSQL:
+
+``` text
+postgres=# CREATE TABLE "public"."test" (
+"int_id" SERIAL,
+"int_nullable" INT NULL DEFAULT NULL,
+"float" FLOAT NOT NULL,
+"str" VARCHAR(100) NOT NULL DEFAULT '',
+"float_nullable" FLOAT NULL DEFAULT NULL,
+PRIMARY KEY (int_id));
+
+CREATE TABLE
+
+postgres=# INSERT INTO test (int_id, str, "float") VALUES (1,'test',2);
+INSERT 0 1
+
+postgresql> SELECT * FROM test;
+  int_id | int_nullable | float | str  | float_nullable
+ --------+--------------+-------+------+----------------
+       1 |              |     2 | test |
+(1 row)
+```
+
+Selecting data from ClickHouse:
+
+```sql
+SELECT * FROM postgresql('localhost:5432', 'test', 'test', 'postgresql_user', 'password') WHERE str IN ('test');
+```
+
+``` text
+┌─int_id─┬─int_nullable─┬─float─┬─str──┬─float_nullable─┐
+│      1 │         ᴺᵁᴸᴸ │     2 │ test │           ᴺᵁᴸᴸ │
+└────────┴──────────────┴───────┴──────┴────────────────┘
+```
+
+Inserting:
+
+```sql
+INSERT INTO TABLE FUNCTION postgresql('localhost:5432', 'test', 'test', 'postgrsql_user', 'password') (int_id, float) VALUES (2, 3);
+SELECT * FROM postgresql('localhost:5432', 'test', 'test', 'postgresql_user', 'password');
+```
+
+``` text
+┌─int_id─┬─int_nullable─┬─float─┬─str──┬─float_nullable─┐
+│      1 │         ᴺᵁᴸᴸ │     2 │ test │           ᴺᵁᴸᴸ │
+│      2 │         ᴺᵁᴸᴸ │     3 │      │           ᴺᵁᴸᴸ │
+└────────┴──────────────┴───────┴──────┴────────────────┘
+```
+
+Using Non-default Schema:
+
+```text
+postgres=# CREATE SCHEMA "nice.schema";
+
+postgres=# CREATE TABLE "nice.schema"."nice.table" (a integer);
+
+postgres=# INSERT INTO "nice.schema"."nice.table" SELECT i FROM generate_series(0, 99) as t(i)
+```
+
+```sql
+CREATE TABLE pg_table_schema_with_dots (a UInt32)
+        ENGINE PostgreSQL('localhost:5432', 'clickhouse', 'nice.table', 'postgrsql_user', 'password', 'nice.schema');
+```
+
+**See Also**
+
+-   [The PostgreSQL table engine](../../engines/table-engines/integrations/postgresql.md)
+-   [Using PostgreSQL as a source of external dictionary](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-postgresql)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/table-functions/postgresql/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/table-functions/remote.md b/docs/en/reference/sql-reference/table-functions/remote.md
new file mode 100644
index 00000000000..0eae00564ba
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/remote.md
@@ -0,0 +1,98 @@
+---
+sidebar_position: 40
+sidebar_label: remote
+---
+
+# remote, remoteSecure {#remote-remotesecure}
+
+Allows to access remote servers without creating a [Distributed](../../engines/table-engines/special/distributed.md) table. `remoteSecure` - same as `remote` but with a secured connection.
+
+Both functions can be used in `SELECT` and `INSERT` queries.
+
+**Syntax**
+
+``` sql
+remote('addresses_expr', db, table[, 'user'[, 'password'], sharding_key])
+remote('addresses_expr', db.table[, 'user'[, 'password'], sharding_key])
+remoteSecure('addresses_expr', db, table[, 'user'[, 'password'], sharding_key])
+remoteSecure('addresses_expr', db.table[, 'user'[, 'password'], sharding_key])
+```
+
+**Parameters**
+
+- `addresses_expr` — An expression that generates addresses of remote servers. This may be just one server address. The server address is `host:port`, or just `host`.
+
+    The host can be specified as the server name, or as the IPv4 or IPv6 address. An IPv6 address is specified in square brackets.
+
+    The port is the TCP port on the remote server. If the port is omitted, it uses [tcp_port](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-tcp_port) from the server’s config file in `remote` (by default, 9000) and [tcp_port_secure](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-tcp_port_secure) in `remoteSecure` (by default, 9440).
+
+    The port is required for an IPv6 address.
+
+    Type: [String](../../sql-reference/data-types/string.md).
+
+- `db` — Database name. Type: [String](../../sql-reference/data-types/string.md).
+- `table` — Table name. Type: [String](../../sql-reference/data-types/string.md).
+- `user` — User name. If the user is not specified, `default` is used. Type: [String](../../sql-reference/data-types/string.md).
+- `password` — User password. If the password is not specified, an empty password is used. Type: [String](../../sql-reference/data-types/string.md).
+- `sharding_key` — Sharding key to support distributing data across nodes. For example: `insert into remote('127.0.0.1:9000,127.0.0.2', db, table, 'default', rand())`. Type: [UInt32](../../sql-reference/data-types/int-uint.md).
+
+**Returned value**
+
+The dataset from remote servers.
+
+**Usage**
+
+Using the `remote` table function is less optimal than creating a `Distributed` table because in this case the server connection is re-established for every request. Also, if hostnames are set, the names are resolved, and errors are not counted when working with various replicas. When processing a large number of queries, always create the `Distributed` table ahead of time, and do not use the `remote` table function.
+
+The `remote` table function can be useful in the following cases:
+
+-   Accessing a specific server for data comparison, debugging, and testing.
+-   Queries between various ClickHouse clusters for research purposes.
+-   Infrequent distributed requests that are made manually.
+-   Distributed requests where the set of servers is re-defined each time.
+
+**Adresses**
+
+``` text
+example01-01-1
+example01-01-1:9000
+localhost
+127.0.0.1
+[::]:9000
+[2a02:6b8:0:1111::11]:9000
+```
+
+Multiple addresses can be comma-separated. In this case, ClickHouse will use distributed processing, so it will send the query to all specified addresses (like shards with different data). Example:
+
+``` text
+example01-01-1,example01-02-1
+```
+
+**Examples**
+
+Selecting data from a remote server:
+
+``` sql
+SELECT * FROM remote('127.0.0.1', db.remote_engine_table) LIMIT 3;
+```
+
+Inserting data from a remote server into a table:
+
+``` sql
+CREATE TABLE remote_table (name String, value UInt32) ENGINE=Memory;
+INSERT INTO FUNCTION remote('127.0.0.1', currentDatabase(), 'remote_table') VALUES ('test', 42);
+SELECT * FROM remote_table;
+```
+
+## Globs in Addresses {globs-in-addresses}
+
+Patterns in curly brackets `{ }` are used to generate a set of shards and to specify replicas. If there are multiple pairs of curly brackets, then the direct product of the corresponding sets is generated.
+The following pattern types are supported.
+
+- {*a*,*b*} - Any number of variants separated by a comma. The pattern is replaced with *a* in the first shard address and it is replaced with *b* in the second shard address and so on. For instance, `example0{1,2}-1` generates addresses `example01-1` and `example02-1`.
+- {*n*..*m*} - A range of numbers. This pattern generates shard addresses with incrementing indices from *n* to *m*. `example0{1..2}-1` generates `example01-1` and `example02-1`.
+- {*0n*..*0m*} - A range of numbers with leading zeroes. This modification preserves leading zeroes in indices. The pattern `example{01..03}-1` generates `example01-1`, `example02-1` and `example03-1`.
+- {*a*|*b*} - Any number of variants separated by a `|`. The pattern specifies replicas. For instance, `example01-{1|2}` generates replicas `example01-1` and `example01-2`.
+
+The query will be sent to the first healthy replica. However, for `remote` the replicas are iterated in the order currently set in the [load_balancing](../../operations/settings/settings.md#settings-load_balancing) setting.
+The number of generated addresses is limited by [table_function_remote_max_addresses](../../operations/settings/settings.md#table_function_remote_max_addresses) setting.
diff --git a/docs/en/reference/sql-reference/table-functions/s3.md b/docs/en/reference/sql-reference/table-functions/s3.md
new file mode 100644
index 00000000000..61dda209ee6
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/s3.md
@@ -0,0 +1,157 @@
+---
+sidebar_position: 45
+sidebar_label: s3
+---
+
+# s3 Table Function {#s3-table-function}
+
+Provides table-like interface to select/insert files in [Amazon S3](https://aws.amazon.com/s3/). This table function is similar to [hdfs](../../sql-reference/table-functions/hdfs.md), but provides S3-specific features.
+
+**Syntax**
+
+``` sql
+s3(path, [aws_access_key_id, aws_secret_access_key,] format, structure, [compression])
+```
+
+**Arguments**
+
+-   `path` — Bucket url with path to file. Supports following wildcards in readonly mode: `*`, `?`, `{abc,def}` and `{N..M}` where `N`, `M` — numbers, `'abc'`, `'def'` — strings. For more information see [here](../../engines/table-engines/integrations/s3.md#wildcards-in-path).
+-   `format` — The [format](../../interfaces/formats.md#formats) of the file.
+-   `structure` — Structure of the table. Format `'column1_name column1_type, column2_name column2_type, ...'`.
+-   `compression` — Parameter is optional. Supported values: `none`, `gzip/gz`, `brotli/br`, `xz/LZMA`, `zstd/zst`. By default, it will autodetect compression by file extension.
+
+**Returned value**
+
+A table with the specified structure for reading or writing data in the specified file.
+
+**Examples**
+
+Selecting the first two rows from the table from S3 file `https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/data.csv`:
+
+``` sql
+SELECT *
+FROM s3('https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/data.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32')
+LIMIT 2;
+```
+
+``` text
+┌─column1─┬─column2─┬─column3─┐
+│       1 │       2 │       3 │
+│       3 │       2 │       1 │
+└─────────┴─────────┴─────────┘
+```
+
+The similar but from file with `gzip` compression:
+
+``` sql
+SELECT *
+FROM s3('https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/data.csv.gz', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32', 'gzip')
+LIMIT 2;
+```
+
+``` text
+┌─column1─┬─column2─┬─column3─┐
+│       1 │       2 │       3 │
+│       3 │       2 │       1 │
+└─────────┴─────────┴─────────┘
+```
+
+## Usage {#usage-examples}
+
+Suppose that we have several files with following URIs on S3:
+
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/some_prefix/some_file_1.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/some_prefix/some_file_2.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/some_prefix/some_file_3.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/some_prefix/some_file_4.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/another_prefix/some_file_1.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/another_prefix/some_file_2.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/another_prefix/some_file_3.csv'
+-   'https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/another_prefix/some_file_4.csv'
+
+Count the amount of rows in files ending with numbers from 1 to 3:
+
+``` sql
+SELECT count(*)
+FROM s3('https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/{some,another}_prefix/some_file_{1..3}.csv', 'CSV', 'name String, value UInt32')
+```
+
+``` text
+┌─count()─┐
+│      18 │
+└─────────┘
+```
+
+Count the total amount of rows in all files in these two directories:
+
+``` sql
+SELECT count(*)
+FROM s3('https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/{some,another}_prefix/*', 'CSV', 'name String, value UInt32')
+```
+
+``` text
+┌─count()─┐
+│      24 │
+└─────────┘
+```
+
+:::warning
+If your listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
+:::
+
+Count the total amount of rows in files named `file-000.csv`, `file-001.csv`, … , `file-999.csv`:
+
+``` sql
+SELECT count(*)
+FROM s3('https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/big_prefix/file-{000..999}.csv', 'CSV', 'name String, value UInt32');
+```
+
+``` text
+┌─count()─┐
+│      12 │
+└─────────┘
+```
+
+Insert data into file `test-data.csv.gz`:
+
+``` sql
+INSERT INTO FUNCTION s3('https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/test-data.csv.gz', 'CSV', 'name String, value UInt32', 'gzip')
+VALUES ('test-data', 1), ('test-data-2', 2);
+```
+
+Insert data into file `test-data.csv.gz` from existing table:
+
+``` sql
+INSERT INTO FUNCTION s3('https://clickhouse-public-datasets.s3.amazonaws.com/my-test-bucket-768/test-data.csv.gz', 'CSV', 'name String, value UInt32', 'gzip')
+SELECT name, value FROM existing_table;
+```
+
+## Partitioned Write {#partitioned-write}
+
+If you specify `PARTITION BY` expression when inserting data into `S3` table, a separate file is created for each partition value. Splitting the data into separate files helps to improve reading operations efficiency.
+
+**Examples**
+
+1. Using partition ID in a key creates separate files:
+
+```sql
+INSERT INTO TABLE FUNCTION
+    s3('http://bucket.amazonaws.com/my_bucket/file_{_partition_id}.csv', 'CSV', 'a String, b UInt32, c UInt32')
+    PARTITION BY a VALUES ('x', 2, 3), ('x', 4, 5), ('y', 11, 12), ('y', 13, 14), ('z', 21, 22), ('z', 23, 24);
+```
+As a result, the data is written into three files: `file_x.csv`, `file_y.csv`, and `file_z.csv`.
+
+2. Using partition ID in a bucket name creates files in different buckets:
+
+```sql
+INSERT INTO TABLE FUNCTION
+    s3('http://bucket.amazonaws.com/my_bucket_{_partition_id}/file.csv', 'CSV', 'a UInt32, b UInt32, c UInt32')
+    PARTITION BY a VALUES (1, 2, 3), (1, 4, 5), (10, 11, 12), (10, 13, 14), (20, 21, 22), (20, 23, 24);
+```
+As a result, the data is written into three files in different buckets: `my_bucket_1/file.csv`, `my_bucket_10/file.csv`, and `my_bucket_20/file.csv`.
+
+**See Also**
+
+-   [S3 engine](../../engines/table-engines/integrations/s3.md)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/table-functions/s3/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/table-functions/s3Cluster.md b/docs/en/reference/sql-reference/table-functions/s3Cluster.md
new file mode 100644
index 00000000000..dbd3538c692
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/s3Cluster.md
@@ -0,0 +1,49 @@
+---
+sidebar_position: 55
+sidebar_label: s3Cluster
+---
+
+# s3Cluster Table Function {#s3Cluster-table-function}
+
+Allows processing files from [Amazon S3](https://aws.amazon.com/s3/) in parallel from many nodes in a specified cluster. On initiator it creates a connection to all nodes in the cluster, discloses asterics in S3 file path, and dispatches each file dynamically. On the worker node it asks the initiator about the next task to process and processes it. This is repeated until all tasks are finished.
+
+**Syntax**
+
+``` sql
+s3Cluster(cluster_name, source, [access_key_id, secret_access_key,] format, structure)
+```
+
+**Arguments**
+
+-   `cluster_name` — Name of a cluster that is used to build a set of addresses and connection parameters to remote and local servers.
+-   `source` — URL to a file or a bunch of files. Supports following wildcards in readonly mode: `*`, `?`, `{'abc','def'}` and `{N..M}` where `N`, `M` — numbers, `abc`, `def` — strings. For more information see [Wildcards In Path](../../engines/table-engines/integrations/s3.md#wildcards-in-path).
+-   `access_key_id` and `secret_access_key` — Keys that specify credentials to use with given endpoint. Optional.
+-   `format` — The [format](../../interfaces/formats.md#formats) of the file.
+-   `structure` — Structure of the table. Format `'column1_name column1_type, column2_name column2_type, ...'`.
+
+**Returned value**
+
+A table with the specified structure for reading or writing data in the specified file.
+
+**Examples**
+
+Select the data from all files in the cluster `cluster_simple`:
+
+``` sql
+SELECT * FROM s3Cluster('cluster_simple', 'http://minio1:9001/root/data/{clickhouse,database}/*', 'minio', 'minio123', 'CSV', 'name String, value UInt32, polygon Array(Array(Tuple(Float64, Float64)))') ORDER BY (name, value, polygon);
+```
+
+Count the total amount of rows in all files in the cluster `cluster_simple`:
+
+``` sql
+SELECT count(*) FROM s3Cluster('cluster_simple', 'http://minio1:9001/root/data/{clickhouse,database}/*', 'minio', 'minio123', 'CSV', 'name String, value UInt32, polygon Array(Array(Tuple(Float64, Float64)))');
+```
+
+:::warning    
+If your listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
+:::
+
+**See Also**
+
+-   [S3 engine](../../engines/table-engines/integrations/s3.md)
+-   [s3 table function](../../sql-reference/table-functions/s3.md)
diff --git a/docs/en/reference/sql-reference/table-functions/sqlite.md b/docs/en/reference/sql-reference/table-functions/sqlite.md
new file mode 100644
index 00000000000..6058843ae61
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/sqlite.md
@@ -0,0 +1,45 @@
+---
+sidebar_position: 55
+sidebar_label: sqlite
+---
+
+## sqlite {#sqlite}
+
+Allows to perform queries on a data stored in an [SQLite](../../engines/database-engines/sqlite.md) database.
+
+**Syntax** 
+
+``` sql
+    sqlite('db_path', 'table_name')
+```
+
+**Arguments** 
+
+-   `db_path` — Path to a file with an SQLite database. [String](../../sql-reference/data-types/string.md).
+-   `table_name` — Name of a table in the SQLite database. [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+-   A table object with the same columns as in the original `SQLite` table.
+
+**Example**
+
+Query:
+
+``` sql
+SELECT * FROM sqlite('sqlite.db', 'table1') ORDER BY col2;
+```
+
+Result:
+
+``` text
+┌─col1──┬─col2─┐
+│ line1 │    1 │
+│ line2 │    2 │
+│ line3 │    3 │
+└───────┴──────┘
+```
+
+**See Also** 
+
+-   [SQLite](../../engines/table-engines/integrations/sqlite.md) table engine
\ No newline at end of file
diff --git a/docs/en/reference/sql-reference/table-functions/url.md b/docs/en/reference/sql-reference/table-functions/url.md
new file mode 100644
index 00000000000..3f2f9c6a710
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/url.md
@@ -0,0 +1,47 @@
+---
+sidebar_position: 41
+sidebar_label: url
+---
+
+# url {#url}
+
+`url` function creates a table from the `URL` with given `format` and `structure`.
+
+`url` function may be used in `SELECT` and `INSERT` queries on data in [URL](../../engines/table-engines/special/url.md) tables.
+
+**Syntax**
+
+``` sql
+url(URL, format, structure)
+```
+
+**Parameters**
+
+- `URL` — HTTP or HTTPS server address, which can accept `GET` or `POST` requests (for `SELECT` or `INSERT` queries correspondingly). Type: [String](../../sql-reference/data-types/string.md).
+- `format` — [Format](../../interfaces/formats.md#formats) of the data. Type: [String](../../sql-reference/data-types/string.md).
+- `structure` — Table structure in `'UserID UInt64, Name String'` format. Determines column names and types. Type: [String](../../sql-reference/data-types/string.md).
+
+**Returned value**
+
+A table with the specified format and structure and with data from the defined `URL`.
+
+**Examples**
+
+Getting the first 3 lines of a table that contains columns of `String` and [UInt32](../../sql-reference/data-types/int-uint.md) type from HTTP-server which answers in [CSV](../../interfaces/formats.md#csv) format.
+
+``` sql
+SELECT * FROM url('http://127.0.0.1:12345/', CSV, 'column1 String, column2 UInt32') LIMIT 3;
+```
+
+Inserting data from a `URL` into a table:
+
+``` sql
+CREATE TABLE test_table (column1 String, column2 UInt32) ENGINE=Memory;
+INSERT INTO FUNCTION url('http://127.0.0.1:8123/?query=INSERT+INTO+test_table+FORMAT+CSV', 'CSV', 'column1 String, column2 UInt32') VALUES ('http interface', 42);
+SELECT * FROM test_table;
+```
+
+## Globs in URL {globs-in-url}
+
+Patterns in curly brackets `{ }` are used to generate a set of shards or to specify failover addresses. Supported pattern types and examples see in the description of the [remote](remote.md#globs-in-addresses) function.
+Character `|` inside patterns is used to specify failover addresses. They are iterated in the same order as listed in the pattern. The number of generated addresses is limited by [glob_expansion_max_elements](../../operations/settings/settings.md#glob_expansion_max_elements) setting.
diff --git a/docs/en/reference/sql-reference/table-functions/view.md b/docs/en/reference/sql-reference/table-functions/view.md
new file mode 100644
index 00000000000..727cc04e5a2
--- /dev/null
+++ b/docs/en/reference/sql-reference/table-functions/view.md
@@ -0,0 +1,68 @@
+---
+sidebar_position: 51
+sidebar_label: view
+---
+
+## view {#view}
+
+Turns a subquery into a table. The function implements views (see [CREATE VIEW](https://clickhouse.com/docs/en/sql-reference/statements/create/view/#create-view)). The resulting table does not store data, but only stores the specified `SELECT` query. When reading from the table, ClickHouse executes the query and deletes all unnecessary columns from the result.
+
+**Syntax**
+
+``` sql
+view(subquery)
+```
+
+**Arguments**
+
+-   `subquery` — `SELECT` query.
+
+**Returned value**
+
+-   A table.
+
+**Example**
+
+Input table:
+
+``` text
+┌─id─┬─name─────┬─days─┐
+│  1 │ January  │   31 │
+│  2 │ February │   29 │
+│  3 │ March    │   31 │
+│  4 │ April    │   30 │
+└────┴──────────┴──────┘
+```
+
+Query:
+
+``` sql
+SELECT * FROM view(SELECT name FROM months);
+```
+
+Result:
+
+``` text
+┌─name─────┐
+│ January  │
+│ February │
+│ March    │
+│ April    │
+└──────────┘
+```
+
+You can use the `view` function as a parameter of the [remote](https://clickhouse.com/docs/en/sql-reference/table-functions/remote/#remote-remotesecure) and [cluster](https://clickhouse.com/docs/en/sql-reference/table-functions/cluster/#cluster-clusterallreplicas) table functions:
+
+``` sql
+SELECT * FROM remote(`127.0.0.1`, view(SELECT a, b, c FROM table_name));
+```
+
+``` sql
+SELECT * FROM cluster(`cluster_name`, view(SELECT a, b, c FROM table_name));
+```
+
+**See Also**
+
+-   [View Table Engine](https://clickhouse.com/docs/en/engines/table-engines/special/view/)
+
+[Original article](https://clickhouse.com/docs/en/sql-reference/table-functions/view/) <!--hide-->
diff --git a/docs/en/reference/sql-reference/window-functions/index.md b/docs/en/reference/sql-reference/window-functions/index.md
new file mode 100644
index 00000000000..e9a15995a16
--- /dev/null
+++ b/docs/en/reference/sql-reference/window-functions/index.md
@@ -0,0 +1,57 @@
+---
+sidebar_position: 62
+sidebar_label: Window Functions
+---
+
+# Window Functions
+
+ClickHouse supports the standard grammar for defining windows and window functions. The following features are currently supported:
+
+| Feature | Support or workaround |
+| --------| ----------|
+| ad hoc window specification (`count(*) over (partition by id order by time desc)`) | supported |
+| expressions involving window functions, e.g. `(count(*) over ()) / 2)` | not supported, wrap in a subquery ([feature request](https://github.com/ClickHouse/ClickHouse/issues/19857)) |
+| `WINDOW` clause (`select ... from table window w as (partiton by id)`) | supported |
+| `ROWS` frame | supported |
+| `RANGE` frame | supported, the default |
+| `INTERVAL` syntax for `DateTime` `RANGE OFFSET` frame | not supported, specify the number of seconds instead |
+| `GROUPS` frame | not supported |
+| Calculating aggregate functions over a frame (`sum(value) over (order by time)`) | all aggregate functions are supported |
+| `rank()`, `dense_rank()`, `row_number()` | supported |
+| `lag/lead(value, offset)` | Not supported. Workarounds: |
+|  | 1) replace with `any(value) over (.... rows between <offset> preceding and <offset> preceding)`, or `following` for `lead`|
+|  | 2) use `lagInFrame/leadInFrame`, which are analogous, but respect the window frame. To get behavior identical to `lag/lead`, use `rows between unbounded preceding and unbounded following` |
+
+## References
+
+### GitHub Issues
+
+The roadmap for the initial support of window functions is [in this issue](https://github.com/ClickHouse/ClickHouse/issues/18097).
+
+All GitHub issues related to window funtions have the [comp-window-functions](https://github.com/ClickHouse/ClickHouse/labels/comp-window-functions) tag.
+
+### Tests
+
+These tests contain the examples of the currently supported grammar:
+
+https://github.com/ClickHouse/ClickHouse/blob/master/tests/performance/window_functions.xml
+
+https://github.com/ClickHouse/ClickHouse/blob/master/tests/queries/0_stateless/01591_window_functions.sql
+
+### Postgres Docs
+
+https://www.postgresql.org/docs/current/sql-select.html#SQL-WINDOW
+
+https://www.postgresql.org/docs/devel/sql-expressions.html#SYNTAX-WINDOW-FUNCTIONS
+
+https://www.postgresql.org/docs/devel/functions-window.html
+
+https://www.postgresql.org/docs/devel/tutorial-window.html
+
+### MySQL Docs
+
+https://dev.mysql.com/doc/refman/8.0/en/window-function-descriptions.html
+
+https://dev.mysql.com/doc/refman/8.0/en/window-functions-usage.html
+
+https://dev.mysql.com/doc/refman/8.0/en/window-functions-frames.html
diff --git a/docs/en/reference/whats-new/_category_.yml b/docs/en/reference/whats-new/_category_.yml
new file mode 100644
index 00000000000..00e1c136455
--- /dev/null
+++ b/docs/en/reference/whats-new/_category_.yml
@@ -0,0 +1,8 @@
+position: 100
+label: "What's New"
+collapsible: true
+collapsed: true
+link:
+  type: generated-index
+  title: "What's New"
+  slug: /en/whats-new
\ No newline at end of file
diff --git a/docs/en/reference/whats-new/changelog/2017.md b/docs/en/reference/whats-new/changelog/2017.md
new file mode 100644
index 00000000000..af82c69386a
--- /dev/null
+++ b/docs/en/reference/whats-new/changelog/2017.md
@@ -0,0 +1,266 @@
+---
+toc_priority: 79
+toc_title: '2017'
+---
+
+### ClickHouse Release 1.1.54327, 2017-12-21 {#clickhouse-release-1-1-54327-2017-12-21}
+
+This release contains bug fixes for the previous release 1.1.54318:
+
+-   Fixed bug with possible race condition in replication that could lead to data loss. This issue affects versions 1.1.54310 and 1.1.54318. If you use one of these versions with Replicated tables, the update is strongly recommended. This issue shows in logs in Warning messages like `Part ... from own log does not exist.` The issue is relevant even if you do not see these messages in logs.
+
+### ClickHouse Release 1.1.54318, 2017-11-30 {#clickhouse-release-1-1-54318-2017-11-30}
+
+This release contains bug fixes for the previous release 1.1.54310:
+
+-   Fixed incorrect row deletions during merges in the SummingMergeTree engine
+-   Fixed a memory leak in unreplicated MergeTree engines
+-   Fixed performance degradation with frequent inserts in MergeTree engines
+-   Fixed an issue that was causing the replication queue to stop running
+-   Fixed rotation and archiving of server logs
+
+### ClickHouse Release 1.1.54310, 2017-11-01 {#clickhouse-release-1-1-54310-2017-11-01}
+
+#### New Features: {#new-features}
+
+-   Custom partitioning key for the MergeTree family of table engines.
+-   [Kafka](https://clickhouse.com/docs/en/operations/table_engines/kafka/) table engine.
+-   Added support for loading [CatBoost](https://catboost.yandex/) models and applying them to data stored in ClickHouse.
+-   Added support for time zones with non-integer offsets from UTC.
+-   Added support for arithmetic operations with time intervals.
+-   The range of values for the Date and DateTime types is extended to the year 2105.
+-   Added the `CREATE MATERIALIZED VIEW x TO y` query (specifies an existing table for storing the data of a materialized view).
+-   Added the `ATTACH TABLE` query without arguments.
+-   The processing logic for Nested columns with names ending in -Map in a SummingMergeTree table was extracted to the sumMap aggregate function. You can now specify such columns explicitly.
+-   Max size of the IP trie dictionary is increased to 128M entries.
+-   Added the getSizeOfEnumType function.
+-   Added the sumWithOverflow aggregate function.
+-   Added support for the Cap’n Proto input format.
+-   You can now customize compression level when using the zstd algorithm.
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes}
+
+-   Creation of temporary tables with an engine other than Memory is not allowed.
+-   Explicit creation of tables with the View or MaterializedView engine is not allowed.
+-   During table creation, a new check verifies that the sampling key expression is included in the primary key.
+
+#### Bug Fixes: {#bug-fixes}
+
+-   Fixed hangups when synchronously inserting into a Distributed table.
+-   Fixed nonatomic adding and removing of parts in Replicated tables.
+-   Data inserted into a materialized view is not subjected to unnecessary deduplication.
+-   Executing a query to a Distributed table for which the local replica is lagging and remote replicas are unavailable does not result in an error anymore.
+-   Users do not need access permissions to the `default` database to create temporary tables anymore.
+-   Fixed crashing when specifying the Array type without arguments.
+-   Fixed hangups when the disk volume containing server logs is full.
+-   Fixed an overflow in the toRelativeWeekNum function for the first week of the Unix epoch.
+
+#### Build Improvements: {#build-improvements}
+
+-   Several third-party libraries (notably Poco) were updated and converted to git submodules.
+
+### ClickHouse Release 1.1.54304, 2017-10-19 {#clickhouse-release-1-1-54304-2017-10-19}
+
+#### New Features: {#new-features-1}
+
+-   TLS support in the native protocol (to enable, set `tcp_ssl_port` in `config.xml` ).
+
+#### Bug Fixes: {#bug-fixes-1}
+
+-   `ALTER` for replicated tables now tries to start running as soon as possible.
+-   Fixed crashing when reading data with the setting `preferred_block_size_bytes=0.`
+-   Fixed crashes of `clickhouse-client` when pressing `Page Down`
+-   Correct interpretation of certain complex queries with `GLOBAL IN` and `UNION ALL`
+-   `FREEZE PARTITION` always works atomically now.
+-   Empty POST requests now return a response with code 411.
+-   Fixed interpretation errors for expressions like `CAST(1 AS Nullable(UInt8)).`
+-   Fixed an error when reading `Array(Nullable(String))` columns from `MergeTree` tables.
+-   Fixed crashing when parsing queries like `SELECT dummy AS dummy, dummy AS b`
+-   Users are updated correctly with invalid `users.xml`
+-   Correct handling when an executable dictionary returns a non-zero response code.
+
+### ClickHouse Release 1.1.54292, 2017-09-20 {#clickhouse-release-1-1-54292-2017-09-20}
+
+#### New Features: {#new-features-2}
+
+-   Added the `pointInPolygon` function for working with coordinates on a coordinate plane.
+-   Added the `sumMap` aggregate function for calculating the sum of arrays, similar to `SummingMergeTree`.
+-   Added the `trunc` function. Improved performance of the rounding functions (`round`, `floor`, `ceil`, `roundToExp2`) and corrected the logic of how they work. Changed the logic of the `roundToExp2` function for fractions and negative numbers.
+-   The ClickHouse executable file is now less dependent on the libc version. The same ClickHouse executable file can run on a wide variety of Linux systems. There is still a dependency when using compiled queries (with the setting `compile = 1` , which is not used by default).
+-   Reduced the time needed for dynamic compilation of queries.
+
+#### Bug Fixes: {#bug-fixes-2}
+
+-   Fixed an error that sometimes produced `part ... intersects previous part` messages and weakened replica consistency.
+-   Fixed an error that caused the server to lock up if ZooKeeper was unavailable during shutdown.
+-   Removed excessive logging when restoring replicas.
+-   Fixed an error in the UNION ALL implementation.
+-   Fixed an error in the concat function that occurred if the first column in a block has the Array type.
+-   Progress is now displayed correctly in the system.merges table.
+
+### ClickHouse Release 1.1.54289, 2017-09-13 {#clickhouse-release-1-1-54289-2017-09-13}
+
+#### New Features: {#new-features-3}
+
+-   `SYSTEM` queries for server administration: `SYSTEM RELOAD DICTIONARY`, `SYSTEM RELOAD DICTIONARIES`, `SYSTEM DROP DNS CACHE`, `SYSTEM SHUTDOWN`, `SYSTEM KILL`.
+-   Added functions for working with arrays: `concat`, `arraySlice`, `arrayPushBack`, `arrayPushFront`, `arrayPopBack`, `arrayPopFront`.
+-   Added `root` and `identity` parameters for the ZooKeeper configuration. This allows you to isolate individual users on the same ZooKeeper cluster.
+-   Added aggregate functions `groupBitAnd`, `groupBitOr`, and `groupBitXor` (for compatibility, they are also available under the names `BIT_AND`, `BIT_OR`, and `BIT_XOR`).
+-   External dictionaries can be loaded from MySQL by specifying a socket in the filesystem.
+-   External dictionaries can be loaded from MySQL over SSL (`ssl_cert`, `ssl_key`, `ssl_ca` parameters).
+-   Added the `max_network_bandwidth_for_user` setting to restrict the overall bandwidth use for queries per user.
+-   Support for `DROP TABLE` for temporary tables.
+-   Support for reading `DateTime` values in Unix timestamp format from the `CSV` and `JSONEachRow` formats.
+-   Lagging replicas in distributed queries are now excluded by default (the default threshold is 5 minutes).
+-   FIFO locking is used during ALTER: an ALTER query isn’t blocked indefinitely for continuously running queries.
+-   Option to set `umask` in the config file.
+-   Improved performance for queries with `DISTINCT` .
+
+#### Bug Fixes: {#bug-fixes-3}
+
+-   Improved the process for deleting old nodes in ZooKeeper. Previously, old nodes sometimes didn’t get deleted if there were very frequent inserts, which caused the server to be slow to shut down, among other things.
+-   Fixed randomization when choosing hosts for the connection to ZooKeeper.
+-   Fixed the exclusion of lagging replicas in distributed queries if the replica is localhost.
+-   Fixed an error where a data part in a `ReplicatedMergeTree` table could be broken after running `ALTER MODIFY` on an element in a `Nested` structure.
+-   Fixed an error that could cause SELECT queries to “hang”.
+-   Improvements to distributed DDL queries.
+-   Fixed the query `CREATE TABLE ... AS <materialized view>`.
+-   Resolved the deadlock in the `ALTER ... CLEAR COLUMN IN PARTITION` query for `Buffer` tables.
+-   Fixed the invalid default value for `Enum` s (0 instead of the minimum) when using the `JSONEachRow` and `TSKV` formats.
+-   Resolved the appearance of zombie processes when using a dictionary with an `executable` source.
+-   Fixed segfault for the HEAD query.
+
+#### Improved Workflow for Developing and Assembling ClickHouse: {#improved-workflow-for-developing-and-assembling-clickhouse}
+
+-   You can use `pbuilder` to build ClickHouse.
+-   You can use `libc++` instead of `libstdc++` for builds on Linux.
+-   Added instructions for using static code analysis tools: `Coverage`, `clang-tidy`, `cppcheck`.
+
+#### Please Note When Upgrading: {#please-note-when-upgrading}
+
+-   There is now a higher default value for the MergeTree setting `max_bytes_to_merge_at_max_space_in_pool` (the maximum total size of data parts to merge, in bytes): it has increased from 100 GiB to 150 GiB. This might result in large merges running after the server upgrade, which could cause an increased load on the disk subsystem. If the free space available on the server is less than twice the total amount of the merges that are running, this will cause all other merges to stop running, including merges of small data parts. As a result, INSERT queries will fail with the message “Merges are processing significantly slower than inserts.” Use the `SELECT * FROM system.merges` query to monitor the situation. You can also check the `DiskSpaceReservedForMerge` metric in the `system.metrics` table, or in Graphite. You do not need to do anything to fix this, since the issue will resolve itself once the large merges finish. If you find this unacceptable, you can restore the previous value for the `max_bytes_to_merge_at_max_space_in_pool` setting. To do this, go to the `<merge_tree>` section in config.xml, set ``` <merge_tree>``<max_bytes_to_merge_at_max_space_in_pool>107374182400</max_bytes_to_merge_at_max_space_in_pool> ``` and restart the server.
+
+### ClickHouse Release 1.1.54284, 2017-08-29 {#clickhouse-release-1-1-54284-2017-08-29}
+
+-   This is a bugfix release for the previous 1.1.54282 release. It fixes leaks in the parts directory in ZooKeeper.
+
+### ClickHouse Release 1.1.54282, 2017-08-23 {#clickhouse-release-1-1-54282-2017-08-23}
+
+This release contains bug fixes for the previous release 1.1.54276:
+
+-   Fixed `DB::Exception: Assertion violation: !_path.empty()` when inserting into a Distributed table.
+-   Fixed parsing when inserting in RowBinary format if input data starts with’;’.
+-   Errors during runtime compilation of certain aggregate functions (e.g. `groupArray()`).
+
+### ClickHouse Release 1.1.54276, 2017-08-16 {#clickhouse-release-1-1-54276-2017-08-16}
+
+#### New Features: {#new-features-4}
+
+-   Added an optional WITH section for a SELECT query. Example query: `WITH 1+1 AS a SELECT a, a*a`
+-   INSERT can be performed synchronously in a Distributed table: OK is returned only after all the data is saved on all the shards. This is activated by the setting insert_distributed_sync=1.
+-   Added the UUID data type for working with 16-byte identifiers.
+-   Added aliases of CHAR, FLOAT and other types for compatibility with the Tableau.
+-   Added the functions toYYYYMM, toYYYYMMDD, and toYYYYMMDDhhmmss for converting time into numbers.
+-   You can use IP addresses (together with the hostname) to identify servers for clustered DDL queries.
+-   Added support for non-constant arguments and negative offsets in the function `substring(str, pos, len).`
+-   Added the max_size parameter for the `groupArray(max_size)(column)` aggregate function, and optimized its performance.
+
+#### Main Changes: {#main-changes}
+
+-   Security improvements: all server files are created with 0640 permissions (can be changed via `<umask>` config parameter).
+-   Improved error messages for queries with invalid syntax.
+-   Significantly reduced memory consumption and improved performance when merging large sections of MergeTree data.
+-   Significantly increased the performance of data merges for the ReplacingMergeTree engine.
+-   Improved performance for asynchronous inserts from a Distributed table by combining multiple source inserts. To enable this functionality, use the setting distributed_directory_monitor_batch_inserts=1.
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-1}
+
+-   Changed the binary format of aggregate states of `groupArray(array_column)` functions for arrays.
+
+#### Complete List of Changes: {#complete-list-of-changes}
+
+-   Added the `output_format_json_quote_denormals` setting, which enables outputting nan and inf values in JSON format.
+-   Optimized stream allocation when reading from a Distributed table.
+-   Settings can be configured in readonly mode if the value does not change.
+-   Added the ability to retrieve non-integer granules of the MergeTree engine in order to meet restrictions on the block size specified in the preferred_block_size_bytes setting. The purpose is to reduce the consumption of RAM and increase cache locality when processing queries from tables with large columns.
+-   Efficient use of indexes that contain expressions like `toStartOfHour(x)` for conditions like `toStartOfHour(x) op сonstexpr.`
+-   Added new settings for MergeTree engines (the merge_tree section in config.xml):
+    -   replicated_deduplication_window_seconds sets the number of seconds allowed for deduplicating inserts in Replicated tables.
+    -   cleanup_delay_period sets how often to start cleanup to remove outdated data.
+    -   replicated_can_become_leader can prevent a replica from becoming the leader (and assigning merges).
+-   Accelerated cleanup to remove outdated data from ZooKeeper.
+-   Multiple improvements and fixes for clustered DDL queries. Of particular interest is the new setting distributed_ddl_task_timeout, which limits the time to wait for a response from the servers in the cluster. If a ddl request has not been performed on all hosts, a response will contain a timeout error and a request will be executed in an async mode.
+-   Improved display of stack traces in the server logs.
+-   Added the “none” value for the compression method.
+-   You can use multiple dictionaries_config sections in config.xml.
+-   It is possible to connect to MySQL through a socket in the file system.
+-   The system.parts table has a new column with information about the size of marks, in bytes.
+
+#### Bug Fixes: {#bug-fixes-4}
+
+-   Distributed tables using a Merge table now work correctly for a SELECT query with a condition on the `_table` field.
+-   Fixed a rare race condition in ReplicatedMergeTree when checking data parts.
+-   Fixed possible freezing on “leader election” when starting a server.
+-   The max_replica_delay_for_distributed_queries setting was ignored when using a local replica of the data source. This has been fixed.
+-   Fixed incorrect behavior of `ALTER TABLE CLEAR COLUMN IN PARTITION` when attempting to clean a non-existing column.
+-   Fixed an exception in the multiIf function when using empty arrays or strings.
+-   Fixed excessive memory allocations when deserializing Native format.
+-   Fixed incorrect auto-update of Trie dictionaries.
+-   Fixed an exception when running queries with a GROUP BY clause from a Merge table when using SAMPLE.
+-   Fixed a crash of GROUP BY when using distributed_aggregation_memory_efficient=1.
+-   Now you can specify the database.table in the right side of IN and JOIN.
+-   Too many threads were used for parallel aggregation. This has been fixed.
+-   Fixed how the “if” function works with FixedString arguments.
+-   SELECT worked incorrectly from a Distributed table for shards with a weight of 0. This has been fixed.
+-   Running `CREATE VIEW IF EXISTS no longer causes crashes.`
+-   Fixed incorrect behavior when input_format_skip_unknown_fields=1 is set and there are negative numbers.
+-   Fixed an infinite loop in the `dictGetHierarchy()` function if there is some invalid data in the dictionary.
+-   Fixed `Syntax error: unexpected (...)` errors when running distributed queries with subqueries in an IN or JOIN clause and Merge tables.
+-   Fixed an incorrect interpretation of a SELECT query from Dictionary tables.
+-   Fixed the “Cannot mremap” error when using arrays in IN and JOIN clauses with more than 2 billion elements.
+-   Fixed the failover for dictionaries with MySQL as the source.
+
+#### Improved Workflow for Developing and Assembling ClickHouse: {#improved-workflow-for-developing-and-assembling-clickhouse-1}
+
+-   Builds can be assembled in Arcadia.
+-   You can use gcc 7 to compile ClickHouse.
+-   Parallel builds using ccache+distcc are faster now.
+
+### ClickHouse Release 1.1.54245, 2017-07-04 {#clickhouse-release-1-1-54245-2017-07-04}
+
+#### New Features: {#new-features-5}
+
+-   Distributed DDL (for example, `CREATE TABLE ON CLUSTER`)
+-   The replicated query `ALTER TABLE CLEAR COLUMN IN PARTITION.`
+-   The engine for Dictionary tables (access to dictionary data in the form of a table).
+-   Dictionary database engine (this type of database automatically has Dictionary tables available for all the connected external dictionaries).
+-   You can check for updates to the dictionary by sending a request to the source.
+-   Qualified column names
+-   Quoting identifiers using double quotation marks.
+-   Sessions in the HTTP interface.
+-   The OPTIMIZE query for a Replicated table can can run not only on the leader.
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-2}
+
+-   Removed SET GLOBAL.
+
+#### Minor Changes: {#minor-changes}
+
+-   Now after an alert is triggered, the log prints the full stack trace.
+-   Relaxed the verification of the number of damaged/extra data parts at startup (there were too many false positives).
+
+#### Bug Fixes: {#bug-fixes-5}
+
+-   Fixed a bad connection “sticking” when inserting into a Distributed table.
+-   GLOBAL IN now works for a query from a Merge table that looks at a Distributed table.
+-   The incorrect number of cores was detected on a Google Compute Engine virtual machine. This has been fixed.
+-   Changes in how an executable source of cached external dictionaries works.
+-   Fixed the comparison of strings containing null characters.
+-   Fixed the comparison of Float32 primary key fields with constants.
+-   Previously, an incorrect estimate of the size of a field could lead to overly large allocations.
+-   Fixed a crash when querying a Nullable column added to a table using ALTER.
+-   Fixed a crash when sorting by a Nullable column, if the number of rows is less than LIMIT.
+-   Fixed an ORDER BY subquery consisting of only constant values.
+-   Previously, a Replicated table could remain in the invalid state after a failed DROP TABLE.
+-   Aliases for scalar subqueries with empty results are no longer lost.
+-   Now a query that used compilation does not fail with an error if the .so file gets damaged.
diff --git a/docs/en/reference/whats-new/changelog/2018.md b/docs/en/reference/whats-new/changelog/2018.md
new file mode 100644
index 00000000000..db09bcd8a03
--- /dev/null
+++ b/docs/en/reference/whats-new/changelog/2018.md
@@ -0,0 +1,1061 @@
+---
+toc_priority: 78
+toc_title: '2018'
+---
+
+## ClickHouse Release 18.16 {#clickhouse-release-18-16}
+
+### ClickHouse Release 18.16.1, 2018-12-21 {#clickhouse-release-18-16-1-2018-12-21}
+
+#### Bug Fixes: {#bug-fixes}
+
+-   Fixed an error that led to problems with updating dictionaries with the ODBC source. [#3825](https://github.com/ClickHouse/ClickHouse/issues/3825), [#3829](https://github.com/ClickHouse/ClickHouse/issues/3829)
+-   JIT compilation of aggregate functions now works with LowCardinality columns. [#3838](https://github.com/ClickHouse/ClickHouse/issues/3838)
+
+#### Improvements: {#improvements}
+
+-   Added the `low_cardinality_allow_in_native_format` setting (enabled by default). When disabled, LowCardinality columns will be converted to ordinary columns for SELECT queries and ordinary columns will be expected for INSERT queries. [#3879](https://github.com/ClickHouse/ClickHouse/pull/3879)
+
+#### Build Improvements: {#build-improvements}
+
+-   Fixes for builds on macOS and ARM.
+
+### ClickHouse Release 18.16.0, 2018-12-14 {#clickhouse-release-18-16-0-2018-12-14}
+
+#### New Features: {#new-features}
+
+-   `DEFAULT` expressions are evaluated for missing fields when loading data in semi-structured input formats (`JSONEachRow`, `TSKV`). The feature is enabled with the `insert_sample_with_metadata` setting. [#3555](https://github.com/ClickHouse/ClickHouse/pull/3555)
+-   The `ALTER TABLE` query now has the `MODIFY ORDER BY` action for changing the sorting key when adding or removing a table column. This is useful for tables in the `MergeTree` family that perform additional tasks when merging based on this sorting key, such as `SummingMergeTree`, `AggregatingMergeTree`, and so on. [#3581](https://github.com/ClickHouse/ClickHouse/pull/3581) [#3755](https://github.com/ClickHouse/ClickHouse/pull/3755)
+-   For tables in the `MergeTree` family, now you can specify a different sorting key (`ORDER BY`) and index (`PRIMARY KEY`). The sorting key can be longer than the index. [#3581](https://github.com/ClickHouse/ClickHouse/pull/3581)
+-   Added the `hdfs` table function and the `HDFS` table engine for importing and exporting data to HDFS. [chenxing-xc](https://github.com/ClickHouse/ClickHouse/pull/3617)
+-   Added functions for working with base64: `base64Encode`, `base64Decode`, `tryBase64Decode`. [Alexander Krasheninnikov](https://github.com/ClickHouse/ClickHouse/pull/3350)
+-   Now you can use a parameter to configure the precision of the `uniqCombined` aggregate function (select the number of HyperLogLog cells). [#3406](https://github.com/ClickHouse/ClickHouse/pull/3406)
+-   Added the `system.contributors` table that contains the names of everyone who made commits in ClickHouse. [#3452](https://github.com/ClickHouse/ClickHouse/pull/3452)
+-   Added the ability to omit the partition for the `ALTER TABLE ... FREEZE` query in order to back up all partitions at once. [#3514](https://github.com/ClickHouse/ClickHouse/pull/3514)
+-   Added `dictGet` and `dictGetOrDefault` functions that do not require specifying the type of return value. The type is determined automatically from the dictionary description. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3564)
+-   Now you can specify comments for a column in the table description and change it using `ALTER`. [#3377](https://github.com/ClickHouse/ClickHouse/pull/3377)
+-   Reading is supported for `Join` type tables with simple keys. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3728)
+-   Now you can specify the options `join_use_nulls`, `max_rows_in_join`, `max_bytes_in_join`, and `join_overflow_mode` when creating a `Join` type table. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3728)
+-   Added the `joinGet` function that allows you to use a `Join` type table like a dictionary. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3728)
+-   Added the `partition_key`, `sorting_key`, `primary_key`, and `sampling_key` columns to the `system.tables` table in order to provide information about table keys. [#3609](https://github.com/ClickHouse/ClickHouse/pull/3609)
+-   Added the `is_in_partition_key`, `is_in_sorting_key`, `is_in_primary_key`, and `is_in_sampling_key` columns to the `system.columns` table. [#3609](https://github.com/ClickHouse/ClickHouse/pull/3609)
+-   Added the `min_time` and `max_time` columns to the `system.parts` table. These columns are populated when the partitioning key is an expression consisting of `DateTime` columns. [Emmanuel Donin de Rosière](https://github.com/ClickHouse/ClickHouse/pull/3800)
+
+#### Bug Fixes: {#bug-fixes-1}
+
+-   Fixes and performance improvements for the `LowCardinality` data type. `GROUP BY` using `LowCardinality(Nullable(...))`. Getting the values of `extremes`. Processing high-order functions. `LEFT ARRAY JOIN`. Distributed `GROUP BY`. Functions that return `Array`. Execution of `ORDER BY`. Writing to `Distributed` tables (nicelulu). Backward compatibility for `INSERT` queries from old clients that implement the `Native` protocol. Support for `LowCardinality` for `JOIN`. Improved performance when working in a single stream. [#3823](https://github.com/ClickHouse/ClickHouse/pull/3823) [#3803](https://github.com/ClickHouse/ClickHouse/pull/3803) [#3799](https://github.com/ClickHouse/ClickHouse/pull/3799) [#3769](https://github.com/ClickHouse/ClickHouse/pull/3769) [#3744](https://github.com/ClickHouse/ClickHouse/pull/3744) [#3681](https://github.com/ClickHouse/ClickHouse/pull/3681) [#3651](https://github.com/ClickHouse/ClickHouse/pull/3651) [#3649](https://github.com/ClickHouse/ClickHouse/pull/3649) [#3641](https://github.com/ClickHouse/ClickHouse/pull/3641) [#3632](https://github.com/ClickHouse/ClickHouse/pull/3632) [#3568](https://github.com/ClickHouse/ClickHouse/pull/3568) [#3523](https://github.com/ClickHouse/ClickHouse/pull/3523) [#3518](https://github.com/ClickHouse/ClickHouse/pull/3518)
+-   Fixed how the `select_sequential_consistency` option works. Previously, when this setting was enabled, an incomplete result was sometimes returned after beginning to write to a new partition. [#2863](https://github.com/ClickHouse/ClickHouse/pull/2863)
+-   Databases are correctly specified when executing DDL `ON CLUSTER` queries and `ALTER UPDATE/DELETE`. [#3772](https://github.com/ClickHouse/ClickHouse/pull/3772) [#3460](https://github.com/ClickHouse/ClickHouse/pull/3460)
+-   Databases are correctly specified for subqueries inside a VIEW. [#3521](https://github.com/ClickHouse/ClickHouse/pull/3521)
+-   Fixed a bug in `PREWHERE` with `FINAL` for `VersionedCollapsingMergeTree`. [7167bfd7](https://github.com/ClickHouse/ClickHouse/commit/7167bfd7b365538f7a91c4307ad77e552ab4e8c1)
+-   Now you can use `KILL QUERY` to cancel queries that have not started yet because they are waiting for the table to be locked. [#3517](https://github.com/ClickHouse/ClickHouse/pull/3517)
+-   Corrected date and time calculations if the clocks were moved back at midnight (this happens in Iran, and happened in Moscow from 1981 to 1983). Previously, this led to the time being reset a day earlier than necessary, and also caused incorrect formatting of the date and time in text format. [#3819](https://github.com/ClickHouse/ClickHouse/pull/3819)
+-   Fixed bugs in some cases of `VIEW` and subqueries that omit the database. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/3521)
+-   Fixed a race condition when simultaneously reading from a `MATERIALIZED VIEW` and deleting a `MATERIALIZED VIEW` due to not locking the internal `MATERIALIZED VIEW`. [#3404](https://github.com/ClickHouse/ClickHouse/pull/3404) [#3694](https://github.com/ClickHouse/ClickHouse/pull/3694)
+-   Fixed the error `Lock handler cannot be nullptr.` [#3689](https://github.com/ClickHouse/ClickHouse/pull/3689)
+-   Fixed query processing when the `compile_expressions` option is enabled (it’s enabled by default). Nondeterministic constant expressions like the `now` function are no longer unfolded. [#3457](https://github.com/ClickHouse/ClickHouse/pull/3457)
+-   Fixed a crash when specifying a non-constant scale argument in `toDecimal32/64/128` functions.
+-   Fixed an error when trying to insert an array with `NULL` elements in the `Values` format into a column of type `Array` without `Nullable` (if `input_format_values_interpret_expressions` = 1). [#3487](https://github.com/ClickHouse/ClickHouse/pull/3487) [#3503](https://github.com/ClickHouse/ClickHouse/pull/3503)
+-   Fixed continuous error logging in `DDLWorker` if ZooKeeper is not available. [8f50c620](https://github.com/ClickHouse/ClickHouse/commit/8f50c620334988b28018213ec0092fe6423847e2)
+-   Fixed the return type for `quantile*` functions from `Date` and `DateTime` types of arguments. [#3580](https://github.com/ClickHouse/ClickHouse/pull/3580)
+-   Fixed the `WITH` clause if it specifies a simple alias without expressions. [#3570](https://github.com/ClickHouse/ClickHouse/pull/3570)
+-   Fixed processing of queries with named sub-queries and qualified column names when `enable_optimize_predicate_expression` is enabled. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/3588)
+-   Fixed the error `Attempt to attach to nullptr thread group` when working with materialized views. [Marek Vavruša](https://github.com/ClickHouse/ClickHouse/pull/3623)
+-   Fixed a crash when passing certain incorrect arguments to the `arrayReverse` function. [73e3a7b6](https://github.com/ClickHouse/ClickHouse/commit/73e3a7b662161d6005e7727d8a711b930386b871)
+-   Fixed the buffer overflow in the `extractURLParameter` function. Improved performance. Added correct processing of strings containing zero bytes. [141e9799](https://github.com/ClickHouse/ClickHouse/commit/141e9799e49201d84ea8e951d1bed4fb6d3dacb5)
+-   Fixed buffer overflow in the `lowerUTF8` and `upperUTF8` functions. Removed the ability to execute these functions over `FixedString` type arguments. [#3662](https://github.com/ClickHouse/ClickHouse/pull/3662)
+-   Fixed a rare race condition when deleting `MergeTree` tables. [#3680](https://github.com/ClickHouse/ClickHouse/pull/3680)
+-   Fixed a race condition when reading from `Buffer` tables and simultaneously performing `ALTER` or `DROP` on the target tables. [#3719](https://github.com/ClickHouse/ClickHouse/pull/3719)
+-   Fixed a segfault if the `max_temporary_non_const_columns` limit was exceeded. [#3788](https://github.com/ClickHouse/ClickHouse/pull/3788)
+
+#### Improvements: {#improvements-1}
+
+-   The server does not write the processed configuration files to the `/etc/clickhouse-server/` directory. Instead, it saves them in the `preprocessed_configs` directory inside `path`. This means that the `/etc/clickhouse-server/` directory does not have write access for the `clickhouse` user, which improves security. [#2443](https://github.com/ClickHouse/ClickHouse/pull/2443)
+-   The `min_merge_bytes_to_use_direct_io` option is set to 10 GiB by default. A merge that forms large parts of tables from the MergeTree family will be performed in `O_DIRECT` mode, which prevents excessive page cache eviction. [#3504](https://github.com/ClickHouse/ClickHouse/pull/3504)
+-   Accelerated server start when there is a very large number of tables. [#3398](https://github.com/ClickHouse/ClickHouse/pull/3398)
+-   Added a connection pool and HTTP `Keep-Alive` for connections between replicas. [#3594](https://github.com/ClickHouse/ClickHouse/pull/3594)
+-   If the query syntax is invalid, the `400 Bad Request` code is returned in the `HTTP` interface (500 was returned previously). [31bc680a](https://github.com/ClickHouse/ClickHouse/commit/31bc680ac5f4bb1d0360a8ba4696fa84bb47d6ab)
+-   The `join_default_strictness` option is set to `ALL` by default for compatibility. [120e2cbe](https://github.com/ClickHouse/ClickHouse/commit/120e2cbe2ff4fbad626c28042d9b28781c805afe)
+-   Removed logging to `stderr` from the `re2` library for invalid or complex regular expressions. [#3723](https://github.com/ClickHouse/ClickHouse/pull/3723)
+-   Added for the `Kafka` table engine: checks for subscriptions before beginning to read from Kafka; the kafka_max_block_size setting for the table. [Marek Vavruša](https://github.com/ClickHouse/ClickHouse/pull/3396)
+-   The `cityHash64`, `farmHash64`, `metroHash64`, `sipHash64`, `halfMD5`, `murmurHash2_32`, `murmurHash2_64`, `murmurHash3_32`, and `murmurHash3_64` functions now work for any number of arguments and for arguments in the form of tuples. [#3451](https://github.com/ClickHouse/ClickHouse/pull/3451) [#3519](https://github.com/ClickHouse/ClickHouse/pull/3519)
+-   The `arrayReverse` function now works with any types of arrays. [73e3a7b6](https://github.com/ClickHouse/ClickHouse/commit/73e3a7b662161d6005e7727d8a711b930386b871)
+-   Added an optional parameter: the slot size for the `timeSlots` function. [Kirill Shvakov](https://github.com/ClickHouse/ClickHouse/pull/3724)
+-   For `FULL` and `RIGHT JOIN`, the `max_block_size` setting is used for a stream of non-joined data from the right table. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3699)
+-   Added the `--secure` command line parameter in `clickhouse-benchmark` and `clickhouse-performance-test` to enable TLS. [#3688](https://github.com/ClickHouse/ClickHouse/pull/3688) [#3690](https://github.com/ClickHouse/ClickHouse/pull/3690)
+-   Type conversion when the structure of a `Buffer` type table does not match the structure of the destination table. [Vitaly Baranov](https://github.com/ClickHouse/ClickHouse/pull/3603)
+-   Added the `tcp_keep_alive_timeout` option to enable keep-alive packets after inactivity for the specified time interval. [#3441](https://github.com/ClickHouse/ClickHouse/pull/3441)
+-   Removed unnecessary quoting of values for the partition key in the `system.parts` table if it consists of a single column. [#3652](https://github.com/ClickHouse/ClickHouse/pull/3652)
+-   The modulo function works for `Date` and `DateTime` data types. [#3385](https://github.com/ClickHouse/ClickHouse/pull/3385)
+-   Added synonyms for the `POWER`, `LN`, `LCASE`, `UCASE`, `REPLACE`, `LOCATE`, `SUBSTR`, and `MID` functions. [#3774](https://github.com/ClickHouse/ClickHouse/pull/3774) [#3763](https://github.com/ClickHouse/ClickHouse/pull/3763) Some function names are case-insensitive for compatibility with the SQL standard. Added syntactic sugar `SUBSTRING(expr FROM start FOR length)` for compatibility with SQL. [#3804](https://github.com/ClickHouse/ClickHouse/pull/3804)
+-   Added the ability to `mlock` memory pages corresponding to `clickhouse-server` executable code to prevent it from being forced out of memory. This feature is disabled by default. [#3553](https://github.com/ClickHouse/ClickHouse/pull/3553)
+-   Improved performance when reading from `O_DIRECT` (with the `min_bytes_to_use_direct_io` option enabled). [#3405](https://github.com/ClickHouse/ClickHouse/pull/3405)
+-   Improved performance of the `dictGet...OrDefault` function for a constant key argument and a non-constant default argument. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3563)
+-   The `firstSignificantSubdomain` function now processes the domains `gov`, `mil`, and `edu`. [Igor Hatarist](https://github.com/ClickHouse/ClickHouse/pull/3601) Improved performance. [#3628](https://github.com/ClickHouse/ClickHouse/pull/3628)
+-   Ability to specify custom environment variables for starting `clickhouse-server` using the `SYS-V init.d` script by defining `CLICKHOUSE_PROGRAM_ENV` in `/etc/default/clickhouse`.
+    [Pavlo Bashynskyi](https://github.com/ClickHouse/ClickHouse/pull/3612)
+-   Correct return code for the clickhouse-server init script. [#3516](https://github.com/ClickHouse/ClickHouse/pull/3516)
+-   The `system.metrics` table now has the `VersionInteger` metric, and `system.build_options` has the added line `VERSION_INTEGER`, which contains the numeric form of the ClickHouse version, such as `18016000`. [#3644](https://github.com/ClickHouse/ClickHouse/pull/3644)
+-   Removed the ability to compare the `Date` type with a number to avoid potential errors like `date = 2018-12-17`, where quotes around the date are omitted by mistake. [#3687](https://github.com/ClickHouse/ClickHouse/pull/3687)
+-   Fixed the behavior of stateful functions like `rowNumberInAllBlocks`. They previously output a result that was one number larger due to starting during query analysis. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3729)
+-   If the `force_restore_data` file can’t be deleted, an error message is displayed. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3794)
+
+#### Build Improvements: {#build-improvements-1}
+
+-   Updated the `jemalloc` library, which fixes a potential memory leak. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3557)
+-   Profiling with `jemalloc` is enabled by default in order to debug builds. [2cc82f5c](https://github.com/ClickHouse/ClickHouse/commit/2cc82f5cbe266421cd4c1165286c2c47e5ffcb15)
+-   Added the ability to run integration tests when only `Docker` is installed on the system. [#3650](https://github.com/ClickHouse/ClickHouse/pull/3650)
+-   Added the fuzz expression test in SELECT queries. [#3442](https://github.com/ClickHouse/ClickHouse/pull/3442)
+-   Added a stress test for commits, which performs functional tests in parallel and in random order to detect more race conditions. [#3438](https://github.com/ClickHouse/ClickHouse/pull/3438)
+-   Improved the method for starting clickhouse-server in a Docker image. [Elghazal Ahmed](https://github.com/ClickHouse/ClickHouse/pull/3663)
+-   For a Docker image, added support for initializing databases using files in the `/docker-entrypoint-initdb.d` directory. [Konstantin Lebedev](https://github.com/ClickHouse/ClickHouse/pull/3695)
+-   Fixes for builds on ARM. [#3709](https://github.com/ClickHouse/ClickHouse/pull/3709)
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes}
+
+-   Removed the ability to compare the `Date` type with a number. Instead of `toDate('2018-12-18') = 17883`, you must use explicit type conversion `= toDate(17883)` [#3687](https://github.com/ClickHouse/ClickHouse/pull/3687)
+
+## ClickHouse Release 18.14 {#clickhouse-release-18-14}
+
+### ClickHouse Release 18.14.19, 2018-12-19 {#clickhouse-release-18-14-19-2018-12-19}
+
+#### Bug Fixes: {#bug-fixes-2}
+
+-   Fixed an error that led to problems with updating dictionaries with the ODBC source. [#3825](https://github.com/ClickHouse/ClickHouse/issues/3825), [#3829](https://github.com/ClickHouse/ClickHouse/issues/3829)
+-   Databases are correctly specified when executing DDL `ON CLUSTER` queries. [#3460](https://github.com/ClickHouse/ClickHouse/pull/3460)
+-   Fixed a segfault if the `max_temporary_non_const_columns` limit was exceeded. [#3788](https://github.com/ClickHouse/ClickHouse/pull/3788)
+
+#### Build Improvements: {#build-improvements-2}
+
+-   Fixes for builds on ARM.
+
+### ClickHouse Release 18.14.18, 2018-12-04 {#clickhouse-release-18-14-18-2018-12-04}
+
+#### Bug Fixes: {#bug-fixes-3}
+
+-   Fixed error in `dictGet...` function for dictionaries of type `range`, if one of the arguments is constant and other is not. [#3751](https://github.com/ClickHouse/ClickHouse/pull/3751)
+-   Fixed error that caused messages `netlink: '...': attribute type 1 has an invalid length` to be printed in Linux kernel log, that was happening only on fresh enough versions of Linux kernel. [#3749](https://github.com/ClickHouse/ClickHouse/pull/3749)
+-   Fixed segfault in function `empty` for argument of `FixedString` type. [Daniel, Dao Quang Minh](https://github.com/ClickHouse/ClickHouse/pull/3703)
+-   Fixed excessive memory allocation when using large value of `max_query_size` setting (a memory chunk of `max_query_size` bytes was preallocated at once). [#3720](https://github.com/ClickHouse/ClickHouse/pull/3720)
+
+#### Build Changes: {#build-changes}
+
+-   Fixed build with LLVM/Clang libraries of version 7 from the OS packages (these libraries are used for runtime query compilation). [#3582](https://github.com/ClickHouse/ClickHouse/pull/3582)
+
+### ClickHouse Release 18.14.17, 2018-11-30 {#clickhouse-release-18-14-17-2018-11-30}
+
+#### Bug Fixes: {#bug-fixes-4}
+
+-   Fixed cases when the ODBC bridge process did not terminate with the main server process. [#3642](https://github.com/ClickHouse/ClickHouse/pull/3642)
+-   Fixed synchronous insertion into the `Distributed` table with a columns list that differs from the column list of the remote table. [#3673](https://github.com/ClickHouse/ClickHouse/pull/3673)
+-   Fixed a rare race condition that can lead to a crash when dropping a MergeTree table. [#3643](https://github.com/ClickHouse/ClickHouse/pull/3643)
+-   Fixed a query deadlock in case when query thread creation fails with the `Resource temporarily unavailable` error. [#3643](https://github.com/ClickHouse/ClickHouse/pull/3643)
+-   Fixed parsing of the `ENGINE` clause when the `CREATE AS table` syntax was used and the `ENGINE` clause was specified before the `AS table` (the error resulted in ignoring the specified engine). [#3692](https://github.com/ClickHouse/ClickHouse/pull/3692)
+
+### ClickHouse Release 18.14.15, 2018-11-21 {#clickhouse-release-18-14-15-2018-11-21}
+
+#### Bug Fixes: {#bug-fixes-5}
+
+-   The size of memory chunk was overestimated while deserializing the column of type `Array(String)` that leads to “Memory limit exceeded” errors. The issue appeared in version 18.12.13. [#3589](https://github.com/ClickHouse/ClickHouse/issues/3589)
+
+### ClickHouse Release 18.14.14, 2018-11-20 {#clickhouse-release-18-14-14-2018-11-20}
+
+#### Bug Fixes: {#bug-fixes-6}
+
+-   Fixed `ON CLUSTER` queries when cluster configured as secure (flag `<secure>`). [#3599](https://github.com/ClickHouse/ClickHouse/pull/3599)
+
+#### Build Changes: {#build-changes-1}
+
+-   Fixed problems (llvm-7 from system, macos) [#3582](https://github.com/ClickHouse/ClickHouse/pull/3582)
+
+### ClickHouse Release 18.14.13, 2018-11-08 {#clickhouse-release-18-14-13-2018-11-08}
+
+#### Bug Fixes: {#bug-fixes-7}
+
+-   Fixed the `Block structure mismatch in MergingSorted stream` error. [#3162](https://github.com/ClickHouse/ClickHouse/issues/3162)
+-   Fixed `ON CLUSTER` queries in case when secure connections were turned on in the cluster config (the `<secure>` flag). [#3465](https://github.com/ClickHouse/ClickHouse/pull/3465)
+-   Fixed an error in queries that used `SAMPLE`, `PREWHERE` and alias columns. [#3543](https://github.com/ClickHouse/ClickHouse/pull/3543)
+-   Fixed a rare `unknown compression method` error when the `min_bytes_to_use_direct_io` setting was enabled. [3544](https://github.com/ClickHouse/ClickHouse/pull/3544)
+
+#### Performance Improvements: {#performance-improvements}
+
+-   Fixed performance regression of queries with `GROUP BY` of columns of UInt16 or Date type when executing on AMD EPYC processors. [Igor Lapko](https://github.com/ClickHouse/ClickHouse/pull/3512)
+-   Fixed performance regression of queries that process long strings. [#3530](https://github.com/ClickHouse/ClickHouse/pull/3530)
+
+#### Build Improvements: {#build-improvements-3}
+
+-   Improvements for simplifying the Arcadia build. [#3475](https://github.com/ClickHouse/ClickHouse/pull/3475), [#3535](https://github.com/ClickHouse/ClickHouse/pull/3535)
+
+### ClickHouse Release 18.14.12, 2018-11-02 {#clickhouse-release-18-14-12-2018-11-02}
+
+#### Bug Fixes: {#bug-fixes-8}
+
+-   Fixed a crash on joining two unnamed subqueries. [#3505](https://github.com/ClickHouse/ClickHouse/pull/3505)
+-   Fixed generating incorrect queries (with an empty `WHERE` clause) when querying external databases. [hotid](https://github.com/ClickHouse/ClickHouse/pull/3477)
+-   Fixed using an incorrect timeout value in ODBC dictionaries. [Marek Vavruša](https://github.com/ClickHouse/ClickHouse/pull/3511)
+
+### ClickHouse Release 18.14.11, 2018-10-29 {#clickhouse-release-18-14-11-2018-10-29}
+
+#### Bug Fixes: {#bug-fixes-9}
+
+-   Fixed the error `Block structure mismatch in UNION stream: different number of columns` in LIMIT queries. [#2156](https://github.com/ClickHouse/ClickHouse/issues/2156)
+-   Fixed errors when merging data in tables containing arrays inside Nested structures. [#3397](https://github.com/ClickHouse/ClickHouse/pull/3397)
+-   Fixed incorrect query results if the `merge_tree_uniform_read_distribution` setting is disabled (it is enabled by default). [#3429](https://github.com/ClickHouse/ClickHouse/pull/3429)
+-   Fixed an error on inserts to a Distributed table in Native format. [#3411](https://github.com/ClickHouse/ClickHouse/issues/3411)
+
+### ClickHouse Release 18.14.10, 2018-10-23 {#clickhouse-release-18-14-10-2018-10-23}
+
+-   The `compile_expressions` setting (JIT compilation of expressions) is disabled by default. [#3410](https://github.com/ClickHouse/ClickHouse/pull/3410)
+-   The `enable_optimize_predicate_expression` setting is disabled by default.
+
+### ClickHouse Release 18.14.9, 2018-10-16 {#clickhouse-release-18-14-9-2018-10-16}
+
+#### New Features: {#new-features-1}
+
+-   The `WITH CUBE` modifier for `GROUP BY` (the alternative syntax `GROUP BY CUBE(...)` is also available). [#3172](https://github.com/ClickHouse/ClickHouse/pull/3172)
+-   Added the `formatDateTime` function. [Alexandr Krasheninnikov](https://github.com/ClickHouse/ClickHouse/pull/2770)
+-   Added the `JDBC` table engine and `jdbc` table function (requires installing clickhouse-jdbc-bridge). [Alexandr Krasheninnikov](https://github.com/ClickHouse/ClickHouse/pull/3210)
+-   Added functions for working with the ISO week number: `toISOWeek`, `toISOYear`, `toStartOfISOYear`, and `toDayOfYear`. [#3146](https://github.com/ClickHouse/ClickHouse/pull/3146)
+-   Now you can use `Nullable` columns for `MySQL` and `ODBC` tables. [#3362](https://github.com/ClickHouse/ClickHouse/pull/3362)
+-   Nested data structures can be read as nested objects in `JSONEachRow` format. Added the `input_format_import_nested_json` setting. [Veloman Yunkan](https://github.com/ClickHouse/ClickHouse/pull/3144)
+-   Parallel processing is available for many `MATERIALIZED VIEW`s when inserting data. See the `parallel_view_processing` setting. [Marek Vavruša](https://github.com/ClickHouse/ClickHouse/pull/3208)
+-   Added the `SYSTEM FLUSH LOGS` query (forced log flushes to system tables such as `query_log`) [#3321](https://github.com/ClickHouse/ClickHouse/pull/3321)
+-   Now you can use pre-defined `database` and `table` macros when declaring `Replicated` tables. [#3251](https://github.com/ClickHouse/ClickHouse/pull/3251)
+-   Added the ability to read `Decimal` type values in engineering notation (indicating powers of ten). [#3153](https://github.com/ClickHouse/ClickHouse/pull/3153)
+
+#### Experimental Features: {#experimental-features}
+
+-   Optimization of the GROUP BY clause for `LowCardinality data types.` [#3138](https://github.com/ClickHouse/ClickHouse/pull/3138)
+-   Optimized calculation of expressions for `LowCardinality data types.` [#3200](https://github.com/ClickHouse/ClickHouse/pull/3200)
+
+#### Improvements: {#improvements-2}
+
+-   Significantly reduced memory consumption for queries with `ORDER BY` and `LIMIT`. See the `max_bytes_before_remerge_sort` setting. [#3205](https://github.com/ClickHouse/ClickHouse/pull/3205)
+-   In the absence of `JOIN` (`LEFT`, `INNER`, …), `INNER JOIN` is assumed. [#3147](https://github.com/ClickHouse/ClickHouse/pull/3147)
+-   Qualified asterisks work correctly in queries with `JOIN`. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/3202)
+-   The `ODBC` table engine correctly chooses the method for quoting identifiers in the SQL dialect of a remote database. [Alexandr Krasheninnikov](https://github.com/ClickHouse/ClickHouse/pull/3210)
+-   The `compile_expressions` setting (JIT compilation of expressions) is enabled by default.
+-   Fixed behavior for simultaneous DROP DATABASE/TABLE IF EXISTS and CREATE DATABASE/TABLE IF NOT EXISTS. Previously, a `CREATE DATABASE ... IF NOT EXISTS` query could return the error message “File … already exists”, and the `CREATE TABLE ... IF NOT EXISTS` and `DROP TABLE IF EXISTS` queries could return `Table ... is creating or attaching right now`. [#3101](https://github.com/ClickHouse/ClickHouse/pull/3101)
+-   LIKE and IN expressions with a constant right half are passed to the remote server when querying from MySQL or ODBC tables. [#3182](https://github.com/ClickHouse/ClickHouse/pull/3182)
+-   Comparisons with constant expressions in a WHERE clause are passed to the remote server when querying from MySQL and ODBC tables. Previously, only comparisons with constants were passed. [#3182](https://github.com/ClickHouse/ClickHouse/pull/3182)
+-   Correct calculation of row width in the terminal for `Pretty` formats, including strings with hieroglyphs. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/3257).
+-   `ON CLUSTER` can be specified for `ALTER UPDATE` queries.
+-   Improved performance for reading data in `JSONEachRow` format. [#3332](https://github.com/ClickHouse/ClickHouse/pull/3332)
+-   Added synonyms for the `LENGTH` and `CHARACTER_LENGTH` functions for compatibility. The `CONCAT` function is no longer case-sensitive. [#3306](https://github.com/ClickHouse/ClickHouse/pull/3306)
+-   Added the `TIMESTAMP` synonym for the `DateTime` type. [#3390](https://github.com/ClickHouse/ClickHouse/pull/3390)
+-   There is always space reserved for query_id in the server logs, even if the log line is not related to a query. This makes it easier to parse server text logs with third-party tools.
+-   Memory consumption by a query is logged when it exceeds the next level of an integer number of gigabytes. [#3205](https://github.com/ClickHouse/ClickHouse/pull/3205)
+-   Added compatibility mode for the case when the client library that uses the Native protocol sends fewer columns by mistake than the server expects for the INSERT query. This scenario was possible when using the clickhouse-cpp library. Previously, this scenario caused the server to crash. [#3171](https://github.com/ClickHouse/ClickHouse/pull/3171)
+-   In a user-defined WHERE expression in `clickhouse-copier`, you can now use a `partition_key` alias (for additional filtering by source table partition). This is useful if the partitioning scheme changes during copying, but only changes slightly. [#3166](https://github.com/ClickHouse/ClickHouse/pull/3166)
+-   The workflow of the `Kafka` engine has been moved to a background thread pool in order to automatically reduce the speed of data reading at high loads. [Marek Vavruša](https://github.com/ClickHouse/ClickHouse/pull/3215).
+-   Support for reading `Tuple` and `Nested` values of structures like `struct` in the `Cap'n'Proto format`. [Marek Vavruša](https://github.com/ClickHouse/ClickHouse/pull/3216)
+-   The list of top-level domains for the `firstSignificantSubdomain` function now includes the domain `biz`. [decaseal](https://github.com/ClickHouse/ClickHouse/pull/3219)
+-   In the configuration of external dictionaries, `null_value` is interpreted as the value of the default data type. [#3330](https://github.com/ClickHouse/ClickHouse/pull/3330)
+-   Support for the `intDiv` and `intDivOrZero` functions for `Decimal`. [b48402e8](https://github.com/ClickHouse/ClickHouse/commit/b48402e8712e2b9b151e0eef8193811d433a1264)
+-   Support for the `Date`, `DateTime`, `UUID`, and `Decimal` types as a key for the `sumMap` aggregate function. [#3281](https://github.com/ClickHouse/ClickHouse/pull/3281)
+-   Support for the `Decimal` data type in external dictionaries. [#3324](https://github.com/ClickHouse/ClickHouse/pull/3324)
+-   Support for the `Decimal` data type in `SummingMergeTree` tables. [#3348](https://github.com/ClickHouse/ClickHouse/pull/3348)
+-   Added specializations for `UUID` in `if`. [#3366](https://github.com/ClickHouse/ClickHouse/pull/3366)
+-   Reduced the number of `open` and `close` system calls when reading from a `MergeTree table`. [#3283](https://github.com/ClickHouse/ClickHouse/pull/3283)
+-   A `TRUNCATE TABLE` query can be executed on any replica (the query is passed to the leader replica). [Kirill Shvakov](https://github.com/ClickHouse/ClickHouse/pull/3375)
+
+#### Bug Fixes: {#bug-fixes-10}
+
+-   Fixed an issue with `Dictionary` tables for `range_hashed` dictionaries. This error occurred in version 18.12.17. [#1702](https://github.com/ClickHouse/ClickHouse/pull/1702)
+-   Fixed an error when loading `range_hashed` dictionaries (the message `Unsupported type Nullable (...)`). This error occurred in version 18.12.17. [#3362](https://github.com/ClickHouse/ClickHouse/pull/3362)
+-   Fixed errors in the `pointInPolygon` function due to the accumulation of inaccurate calculations for polygons with a large number of vertices located close to each other. [#3331](https://github.com/ClickHouse/ClickHouse/pull/3331) [#3341](https://github.com/ClickHouse/ClickHouse/pull/3341)
+-   If after merging data parts, the checksum for the resulting part differs from the result of the same merge in another replica, the result of the merge is deleted and the data part is downloaded from the other replica (this is the correct behavior). But after downloading the data part, it couldn’t be added to the working set because of an error that the part already exists (because the data part was deleted with some delay after the merge). This led to cyclical attempts to download the same data. [#3194](https://github.com/ClickHouse/ClickHouse/pull/3194)
+-   Fixed incorrect calculation of total memory consumption by queries (because of incorrect calculation, the `max_memory_usage_for_all_queries` setting worked incorrectly and the `MemoryTracking` metric had an incorrect value). This error occurred in version 18.12.13. [Marek Vavruša](https://github.com/ClickHouse/ClickHouse/pull/3344)
+-   Fixed the functionality of `CREATE TABLE ... ON CLUSTER ... AS SELECT ...` This error occurred in version 18.12.13. [#3247](https://github.com/ClickHouse/ClickHouse/pull/3247)
+-   Fixed unnecessary preparation of data structures for `JOIN`s on the server that initiates the query if the `JOIN` is only performed on remote servers. [#3340](https://github.com/ClickHouse/ClickHouse/pull/3340)
+-   Fixed bugs in the `Kafka` engine: deadlocks after exceptions when starting to read data, and locks upon completion [Marek Vavruša](https://github.com/ClickHouse/ClickHouse/pull/3215).
+-   For `Kafka` tables, the optional `schema` parameter was not passed (the schema of the `Cap'n'Proto` format). [Vojtech Splichal](https://github.com/ClickHouse/ClickHouse/pull/3150)
+-   If the ensemble of ZooKeeper servers has servers that accept the connection but then immediately close it instead of responding to the handshake, ClickHouse chooses to connect another server. Previously, this produced the error `Cannot read all data. Bytes read: 0. Bytes expected: 4.` and the server couldn’t start. [8218cf3a](https://github.com/ClickHouse/ClickHouse/commit/8218cf3a5f39a43401953769d6d12a0bb8d29da9)
+-   If the ensemble of ZooKeeper servers contains servers for which the DNS query returns an error, these servers are ignored. [17b8e209](https://github.com/ClickHouse/ClickHouse/commit/17b8e209221061325ad7ba0539f03c6e65f87f29)
+-   Fixed type conversion between `Date` and `DateTime` when inserting data in the `VALUES` format (if `input_format_values_interpret_expressions = 1`). Previously, the conversion was performed between the numerical value of the number of days in Unix Epoch time and the Unix timestamp, which led to unexpected results. [#3229](https://github.com/ClickHouse/ClickHouse/pull/3229)
+-   Corrected type conversion between `Decimal` and integer numbers. [#3211](https://github.com/ClickHouse/ClickHouse/pull/3211)
+-   Fixed errors in the `enable_optimize_predicate_expression` setting. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/3231)
+-   Fixed a parsing error in CSV format with floating-point numbers if a non-default CSV separator is used, such as `;` [#3155](https://github.com/ClickHouse/ClickHouse/pull/3155)
+-   Fixed the `arrayCumSumNonNegative` function (it does not accumulate negative values if the accumulator is less than zero). [Aleksey Studnev](https://github.com/ClickHouse/ClickHouse/pull/3163)
+-   Fixed how `Merge` tables work on top of `Distributed` tables when using `PREWHERE`. [#3165](https://github.com/ClickHouse/ClickHouse/pull/3165)
+-   Bug fixes in the `ALTER UPDATE` query.
+-   Fixed bugs in the `odbc` table function that appeared in version 18.12. [#3197](https://github.com/ClickHouse/ClickHouse/pull/3197)
+-   Fixed the operation of aggregate functions with `StateArray` combinators. [#3188](https://github.com/ClickHouse/ClickHouse/pull/3188)
+-   Fixed a crash when dividing a `Decimal` value by zero. [69dd6609](https://github.com/ClickHouse/ClickHouse/commit/69dd6609193beb4e7acd3e6ad216eca0ccfb8179)
+-   Fixed output of types for operations using `Decimal` and integer arguments. [#3224](https://github.com/ClickHouse/ClickHouse/pull/3224)
+-   Fixed the segfault during `GROUP BY` on `Decimal128`. [3359ba06](https://github.com/ClickHouse/ClickHouse/commit/3359ba06c39fcd05bfdb87d6c64154819621e13a)
+-   The `log_query_threads` setting (logging information about each thread of query execution) now takes effect only if the `log_queries` option (logging information about queries) is set to 1. Since the `log_query_threads` option is enabled by default, information about threads was previously logged even if query logging was disabled. [#3241](https://github.com/ClickHouse/ClickHouse/pull/3241)
+-   Fixed an error in the distributed operation of the quantiles aggregate function (the error message `Not found column quantile...`). [292a8855](https://github.com/ClickHouse/ClickHouse/commit/292a885533b8e3b41ce8993867069d14cbd5a664)
+-   Fixed the compatibility problem when working on a cluster of version 18.12.17 servers and older servers at the same time. For distributed queries with GROUP BY keys of both fixed and non-fixed length, if there was a large amount of data to aggregate, the returned data was not always fully aggregated (two different rows contained the same aggregation keys). [#3254](https://github.com/ClickHouse/ClickHouse/pull/3254)
+-   Fixed handling of substitutions in `clickhouse-performance-test`, if the query contains only part of the substitutions declared in the test. [#3263](https://github.com/ClickHouse/ClickHouse/pull/3263)
+-   Fixed an error when using `FINAL` with `PREWHERE`. [#3298](https://github.com/ClickHouse/ClickHouse/pull/3298)
+-   Fixed an error when using `PREWHERE` over columns that were added during `ALTER`. [#3298](https://github.com/ClickHouse/ClickHouse/pull/3298)
+-   Added a check for the absence of `arrayJoin` for `DEFAULT` and `MATERIALIZED` expressions. Previously, `arrayJoin` led to an error when inserting data. [#3337](https://github.com/ClickHouse/ClickHouse/pull/3337)
+-   Added a check for the absence of `arrayJoin` in a `PREWHERE` clause. Previously, this led to messages like `Size ... does not match` or `Unknown compression method` when executing queries. [#3357](https://github.com/ClickHouse/ClickHouse/pull/3357)
+-   Fixed segfault that could occur in rare cases after optimization that replaced AND chains from equality evaluations with the corresponding IN expression. [liuyimin-bytedance](https://github.com/ClickHouse/ClickHouse/pull/3339)
+-   Minor corrections to `clickhouse-benchmark`: previously, client information was not sent to the server; now the number of queries executed is calculated more accurately when shutting down and for limiting the number of iterations. [#3351](https://github.com/ClickHouse/ClickHouse/pull/3351) [#3352](https://github.com/ClickHouse/ClickHouse/pull/3352)
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-1}
+
+-   Removed the `allow_experimental_decimal_type` option. The `Decimal` data type is available for default use. [#3329](https://github.com/ClickHouse/ClickHouse/pull/3329)
+
+## ClickHouse Release 18.12 {#clickhouse-release-18-12}
+
+### ClickHouse Release 18.12.17, 2018-09-16 {#clickhouse-release-18-12-17-2018-09-16}
+
+#### New Features: {#new-features-2}
+
+-   `invalidate_query` (the ability to specify a query to check whether an external dictionary needs to be updated) is implemented for the `clickhouse` source. [#3126](https://github.com/ClickHouse/ClickHouse/pull/3126)
+-   Added the ability to use `UInt*`, `Int*`, and `DateTime` data types (along with the `Date` type) as a `range_hashed` external dictionary key that defines the boundaries of ranges. Now `NULL` can be used to designate an open range. [Vasily Nemkov](https://github.com/ClickHouse/ClickHouse/pull/3123)
+-   The `Decimal` type now supports `var*` and `stddev*` aggregate functions. [#3129](https://github.com/ClickHouse/ClickHouse/pull/3129)
+-   The `Decimal` type now supports mathematical functions (`exp`, `sin` and so on.) [#3129](https://github.com/ClickHouse/ClickHouse/pull/3129)
+-   The `system.part_log` table now has the `partition_id` column. [#3089](https://github.com/ClickHouse/ClickHouse/pull/3089)
+
+#### Bug Fixes: {#bug-fixes-11}
+
+-   `Merge` now works correctly on `Distributed` tables. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/3159)
+-   Fixed incompatibility (unnecessary dependency on the `glibc` version) that made it impossible to run ClickHouse on `Ubuntu Precise` and older versions. The incompatibility arose in version 18.12.13. [#3130](https://github.com/ClickHouse/ClickHouse/pull/3130)
+-   Fixed errors in the `enable_optimize_predicate_expression` setting. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/3107)
+-   Fixed a minor issue with backwards compatibility that appeared when working with a cluster of replicas on versions earlier than 18.12.13 and simultaneously creating a new replica of a table on a server with a newer version (shown in the message `Can not clone replica, because the ... updated to new ClickHouse version`, which is logical, but shouldn’t happen). [#3122](https://github.com/ClickHouse/ClickHouse/pull/3122)
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-2}
+
+-   The `enable_optimize_predicate_expression` option is enabled by default (which is rather optimistic). If query analysis errors occur that are related to searching for the column names, set `enable_optimize_predicate_expression` to 0. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/3107)
+
+### ClickHouse Release 18.12.14, 2018-09-13 {#clickhouse-release-18-12-14-2018-09-13}
+
+#### New Features: {#new-features-3}
+
+-   Added support for `ALTER UPDATE` queries. [#3035](https://github.com/ClickHouse/ClickHouse/pull/3035)
+-   Added the `allow_ddl` option, which restricts the user’s access to DDL queries. [#3104](https://github.com/ClickHouse/ClickHouse/pull/3104)
+-   Added the `min_merge_bytes_to_use_direct_io` option for `MergeTree` engines, which allows you to set a threshold for the total size of the merge (when above the threshold, data part files will be handled using O_DIRECT). [#3117](https://github.com/ClickHouse/ClickHouse/pull/3117)
+-   The `system.merges` system table now contains the `partition_id` column. [#3099](https://github.com/ClickHouse/ClickHouse/pull/3099)
+
+#### Improvements {#improvements-3}
+
+-   If a data part remains unchanged during mutation, it isn’t downloaded by replicas. [#3103](https://github.com/ClickHouse/ClickHouse/pull/3103)
+-   Autocomplete is available for names of settings when working with `clickhouse-client`. [#3106](https://github.com/ClickHouse/ClickHouse/pull/3106)
+
+#### Bug Fixes: {#bug-fixes-12}
+
+-   Added a check for the sizes of arrays that are elements of `Nested` type fields when inserting. [#3118](https://github.com/ClickHouse/ClickHouse/pull/3118)
+-   Fixed an error updating external dictionaries with the `ODBC` source and `hashed` storage. This error occurred in version 18.12.13.
+-   Fixed a crash when creating a temporary table from a query with an `IN` condition. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/3098)
+-   Fixed an error in aggregate functions for arrays that can have `NULL` elements. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/3097)
+
+### ClickHouse Release 18.12.13, 2018-09-10 {#clickhouse-release-18-12-13-2018-09-10}
+
+#### New Features: {#new-features-4}
+
+-   Added the `DECIMAL(digits, scale)` data type (`Decimal32(scale)`, `Decimal64(scale)`, `Decimal128(scale)`). To enable it, use the setting `allow_experimental_decimal_type`. [#2846](https://github.com/ClickHouse/ClickHouse/pull/2846) [#2970](https://github.com/ClickHouse/ClickHouse/pull/2970) [#3008](https://github.com/ClickHouse/ClickHouse/pull/3008) [#3047](https://github.com/ClickHouse/ClickHouse/pull/3047)
+-   New `WITH ROLLUP` modifier for `GROUP BY` (alternative syntax: `GROUP BY ROLLUP(...)`). [#2948](https://github.com/ClickHouse/ClickHouse/pull/2948)
+-   In queries with JOIN, the star character expands to a list of columns in all tables, in compliance with the SQL standard. You can restore the old behavior by setting `asterisk_left_columns_only` to 1 on the user configuration level. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2787)
+-   Added support for JOIN with table functions. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2907)
+-   Autocomplete by pressing Tab in clickhouse-client. [Sergey Shcherbin](https://github.com/ClickHouse/ClickHouse/pull/2447)
+-   Ctrl+C in clickhouse-client clears a query that was entered. [#2877](https://github.com/ClickHouse/ClickHouse/pull/2877)
+-   Added the `join_default_strictness` setting (values: `"`, `'any'`, `'all'`). This allows you to not specify `ANY` or `ALL` for `JOIN`. [#2982](https://github.com/ClickHouse/ClickHouse/pull/2982)
+-   Each line of the server log related to query processing shows the query ID. [#2482](https://github.com/ClickHouse/ClickHouse/pull/2482)
+-   Now you can get query execution logs in clickhouse-client (use the `send_logs_level` setting). With distributed query processing, logs are cascaded from all the servers. [#2482](https://github.com/ClickHouse/ClickHouse/pull/2482)
+-   The `system.query_log` and `system.processes` (`SHOW PROCESSLIST`) tables now have information about all changed settings when you run a query (the nested structure of the `Settings` data). Added the `log_query_settings` setting. [#2482](https://github.com/ClickHouse/ClickHouse/pull/2482)
+-   The `system.query_log` and `system.processes` tables now show information about the number of threads that are participating in query execution (see the `thread_numbers` column). [#2482](https://github.com/ClickHouse/ClickHouse/pull/2482)
+-   Added `ProfileEvents` counters that measure the time spent on reading and writing over the network and reading and writing to disk, the number of network errors, and the time spent waiting when network bandwidth is limited. [#2482](https://github.com/ClickHouse/ClickHouse/pull/2482)
+-   Added `ProfileEvents`counters that contain the system metrics from rusage (you can use them to get information about CPU usage in userspace and the kernel, page faults, and context switches), as well as taskstats metrics (use these to obtain information about I/O wait time, CPU wait time, and the amount of data read and recorded, both with and without page cache). [#2482](https://github.com/ClickHouse/ClickHouse/pull/2482)
+-   The `ProfileEvents` counters are applied globally and for each query, as well as for each query execution thread, which allows you to profile resource consumption by query in detail. [#2482](https://github.com/ClickHouse/ClickHouse/pull/2482)
+-   Added the `system.query_thread_log` table, which contains information about each query execution thread. Added the `log_query_threads` setting. [#2482](https://github.com/ClickHouse/ClickHouse/pull/2482)
+-   The `system.metrics` and `system.events` tables now have built-in documentation. [#3016](https://github.com/ClickHouse/ClickHouse/pull/3016)
+-   Added the `arrayEnumerateDense` function. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2975)
+-   Added the `arrayCumSumNonNegative` and `arrayDifference` functions. [Aleksey Studnev](https://github.com/ClickHouse/ClickHouse/pull/2942)
+-   Added the `retention` aggregate function. [Sundy Li](https://github.com/ClickHouse/ClickHouse/pull/2887)
+-   Now you can add (merge) states of aggregate functions by using the plus operator, and multiply the states of aggregate functions by a nonnegative constant. [#3062](https://github.com/ClickHouse/ClickHouse/pull/3062) [#3034](https://github.com/ClickHouse/ClickHouse/pull/3034)
+-   Tables in the MergeTree family now have the virtual column `_partition_id`. [#3089](https://github.com/ClickHouse/ClickHouse/pull/3089)
+
+#### Experimental Features: {#experimental-features-1}
+
+-   Added the `LowCardinality(T)` data type. This data type automatically creates a local dictionary of values and allows data processing without unpacking the dictionary. [#2830](https://github.com/ClickHouse/ClickHouse/pull/2830)
+-   Added a cache of JIT-compiled functions and a counter for the number of uses before compiling. To JIT compile expressions, enable the `compile_expressions` setting. [#2990](https://github.com/ClickHouse/ClickHouse/pull/2990) [#3077](https://github.com/ClickHouse/ClickHouse/pull/3077)
+
+#### Improvements: {#improvements-4}
+
+-   Fixed the problem with unlimited accumulation of the replication log when there are abandoned replicas. Added an effective recovery mode for replicas with a long lag.
+-   Improved performance of `GROUP BY` with multiple aggregation fields when one of them is string and the others are fixed length.
+-   Improved performance when using `PREWHERE` and with implicit transfer of expressions in `PREWHERE`.
+-   Improved parsing performance for text formats (`CSV`, `TSV`). [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2977) [#2980](https://github.com/ClickHouse/ClickHouse/pull/2980)
+-   Improved performance of reading strings and arrays in binary formats. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2955)
+-   Increased performance and reduced memory consumption for queries to `system.tables` and `system.columns` when there is a very large number of tables on a single server. [#2953](https://github.com/ClickHouse/ClickHouse/pull/2953)
+-   Fixed a performance problem in the case of a large stream of queries that result in an error (the `_dl_addr` function is visible in `perf top`, but the server isn’t using much CPU). [#2938](https://github.com/ClickHouse/ClickHouse/pull/2938)
+-   Conditions are cast into the View (when `enable_optimize_predicate_expression` is enabled). [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2907)
+-   Improvements to the functionality for the `UUID` data type. [#3074](https://github.com/ClickHouse/ClickHouse/pull/3074) [#2985](https://github.com/ClickHouse/ClickHouse/pull/2985)
+-   The `UUID` data type is supported in The-Alchemist dictionaries. [#2822](https://github.com/ClickHouse/ClickHouse/pull/2822)
+-   The `visitParamExtractRaw` function works correctly with nested structures. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2974)
+-   When the `input_format_skip_unknown_fields` setting is enabled, object fields in `JSONEachRow` format are skipped correctly. [BlahGeek](https://github.com/ClickHouse/ClickHouse/pull/2958)
+-   For a `CASE` expression with conditions, you can now omit `ELSE`, which is equivalent to `ELSE NULL`. [#2920](https://github.com/ClickHouse/ClickHouse/pull/2920)
+-   The operation timeout can now be configured when working with ZooKeeper. [urykhy](https://github.com/ClickHouse/ClickHouse/pull/2971)
+-   You can specify an offset for `LIMIT n, m` as `LIMIT n OFFSET m`. [#2840](https://github.com/ClickHouse/ClickHouse/pull/2840)
+-   You can use the `SELECT TOP n` syntax as an alternative for `LIMIT`. [#2840](https://github.com/ClickHouse/ClickHouse/pull/2840)
+-   Increased the size of the queue to write to system tables, so the `SystemLog parameter queue is full` error does not happen as often.
+-   The `windowFunnel` aggregate function now supports events that meet multiple conditions. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2801)
+-   Duplicate columns can be used in a `USING` clause for `JOIN`. [#3006](https://github.com/ClickHouse/ClickHouse/pull/3006)
+-   `Pretty` formats now have a limit on column alignment by width. Use the `output_format_pretty_max_column_pad_width` setting. If a value is wider, it will still be displayed in its entirety, but the other cells in the table will not be too wide. [#3003](https://github.com/ClickHouse/ClickHouse/pull/3003)
+-   The `odbc` table function now allows you to specify the database/schema name. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2885)
+-   Added the ability to use a username specified in the `clickhouse-client` config file. [Vladimir Kozbin](https://github.com/ClickHouse/ClickHouse/pull/2909)
+-   The `ZooKeeperExceptions` counter has been split into three counters: `ZooKeeperUserExceptions`, `ZooKeeperHardwareExceptions`, and `ZooKeeperOtherExceptions`.
+-   `ALTER DELETE` queries work for materialized views.
+-   Added randomization when running the cleanup thread periodically for `ReplicatedMergeTree` tables in order to avoid periodic load spikes when there are a very large number of `ReplicatedMergeTree` tables.
+-   Support for `ATTACH TABLE ... ON CLUSTER` queries. [#3025](https://github.com/ClickHouse/ClickHouse/pull/3025)
+
+#### Bug Fixes: {#bug-fixes-13}
+
+-   Fixed an issue with `Dictionary` tables (throws the `Size of offsets does not match size of column` or `Unknown compression method` exception). This bug appeared in version 18.10.3. [#2913](https://github.com/ClickHouse/ClickHouse/issues/2913)
+-   Fixed a bug when merging `CollapsingMergeTree` tables if one of the data parts is empty (these parts are formed during merge or `ALTER DELETE` if all data was deleted), and the `vertical` algorithm was used for the merge. [#3049](https://github.com/ClickHouse/ClickHouse/pull/3049)
+-   Fixed a race condition during `DROP` or `TRUNCATE` for `Memory` tables with a simultaneous `SELECT`, which could lead to server crashes. This bug appeared in version 1.1.54388. [#3038](https://github.com/ClickHouse/ClickHouse/pull/3038)
+-   Fixed the possibility of data loss when inserting in `Replicated` tables if the `Session is expired` error is returned (data loss can be detected by the `ReplicatedDataLoss` metric). This error occurred in version 1.1.54378. [#2939](https://github.com/ClickHouse/ClickHouse/pull/2939) [#2949](https://github.com/ClickHouse/ClickHouse/pull/2949) [#2964](https://github.com/ClickHouse/ClickHouse/pull/2964)
+-   Fixed a segfault during `JOIN ... ON`. [#3000](https://github.com/ClickHouse/ClickHouse/pull/3000)
+-   Fixed the error searching column names when the `WHERE` expression consists entirely of a qualified column name, such as `WHERE table.column`. [#2994](https://github.com/ClickHouse/ClickHouse/pull/2994)
+-   Fixed the “Not found column” error that occurred when executing distributed queries if a single column consisting of an IN expression with a subquery is requested from a remote server. [#3087](https://github.com/ClickHouse/ClickHouse/pull/3087)
+-   Fixed the `Block structure mismatch in UNION stream: different number of columns` error that occurred for distributed queries if one of the shards is local and the other is not, and optimization of the move to `PREWHERE` is triggered. [#2226](https://github.com/ClickHouse/ClickHouse/pull/2226) [#3037](https://github.com/ClickHouse/ClickHouse/pull/3037) [#3055](https://github.com/ClickHouse/ClickHouse/pull/3055) [#3065](https://github.com/ClickHouse/ClickHouse/pull/3065) [#3073](https://github.com/ClickHouse/ClickHouse/pull/3073) [#3090](https://github.com/ClickHouse/ClickHouse/pull/3090) [#3093](https://github.com/ClickHouse/ClickHouse/pull/3093)
+-   Fixed the `pointInPolygon` function for certain cases of non-convex polygons. [#2910](https://github.com/ClickHouse/ClickHouse/pull/2910)
+-   Fixed the incorrect result when comparing `nan` with integers. [#3024](https://github.com/ClickHouse/ClickHouse/pull/3024)
+-   Fixed an error in the `zlib-ng` library that could lead to segfault in rare cases. [#2854](https://github.com/ClickHouse/ClickHouse/pull/2854)
+-   Fixed a memory leak when inserting into a table with `AggregateFunction` columns, if the state of the aggregate function is not simple (allocates memory separately), and if a single insertion request results in multiple small blocks. [#3084](https://github.com/ClickHouse/ClickHouse/pull/3084)
+-   Fixed a race condition when creating and deleting the same `Buffer` or `MergeTree` table simultaneously.
+-   Fixed the possibility of a segfault when comparing tuples made up of certain non-trivial types, such as tuples. [#2989](https://github.com/ClickHouse/ClickHouse/pull/2989)
+-   Fixed the possibility of a segfault when running certain `ON CLUSTER` queries. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2960)
+-   Fixed an error in the `arrayDistinct` function for `Nullable` array elements. [#2845](https://github.com/ClickHouse/ClickHouse/pull/2845) [#2937](https://github.com/ClickHouse/ClickHouse/pull/2937)
+-   The `enable_optimize_predicate_expression` option now correctly supports cases with `SELECT *`. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2929)
+-   Fixed the segfault when re-initializing the ZooKeeper session. [#2917](https://github.com/ClickHouse/ClickHouse/pull/2917)
+-   Fixed potential blocking when working with ZooKeeper.
+-   Fixed incorrect code for adding nested data structures in a `SummingMergeTree`.
+-   When allocating memory for states of aggregate functions, alignment is correctly taken into account, which makes it possible to use operations that require alignment when implementing states of aggregate functions. [chenxing-xc](https://github.com/ClickHouse/ClickHouse/pull/2808)
+
+#### Security Fix: {#security-fix}
+
+-   Safe use of ODBC data sources. Interaction with ODBC drivers uses a separate `clickhouse-odbc-bridge` process. Errors in third-party ODBC drivers no longer cause problems with server stability or vulnerabilities. [#2828](https://github.com/ClickHouse/ClickHouse/pull/2828) [#2879](https://github.com/ClickHouse/ClickHouse/pull/2879) [#2886](https://github.com/ClickHouse/ClickHouse/pull/2886) [#2893](https://github.com/ClickHouse/ClickHouse/pull/2893) [#2921](https://github.com/ClickHouse/ClickHouse/pull/2921)
+-   Fixed incorrect validation of the file path in the `catBoostPool` table function. [#2894](https://github.com/ClickHouse/ClickHouse/pull/2894)
+-   The contents of system tables (`tables`, `databases`, `parts`, `columns`, `parts_columns`, `merges`, `mutations`, `replicas`, and `replication_queue`) are filtered according to the user’s configured access to databases (`allow_databases`). [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2856)
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-3}
+
+-   In queries with JOIN, the star character expands to a list of columns in all tables, in compliance with the SQL standard. You can restore the old behavior by setting `asterisk_left_columns_only` to 1 on the user configuration level.
+
+#### Build Changes: {#build-changes-2}
+
+-   Most integration tests can now be run by commit.
+-   Code style checks can also be run by commit.
+-   The `memcpy` implementation is chosen correctly when building on CentOS7/Fedora. [Etienne Champetier](https://github.com/ClickHouse/ClickHouse/pull/2912)
+-   When using clang to build, some warnings from `-Weverything` have been added, in addition to the regular `-Wall-Wextra -Werror`. [#2957](https://github.com/ClickHouse/ClickHouse/pull/2957)
+-   Debugging the build uses the `jemalloc` debug option.
+-   The interface of the library for interacting with ZooKeeper is declared abstract. [#2950](https://github.com/ClickHouse/ClickHouse/pull/2950)
+
+## ClickHouse Release 18.10 {#clickhouse-release-18-10}
+
+### ClickHouse Release 18.10.3, 2018-08-13 {#clickhouse-release-18-10-3-2018-08-13}
+
+#### New Features: {#new-features-5}
+
+-   HTTPS can be used for replication. [#2760](https://github.com/ClickHouse/ClickHouse/pull/2760)
+-   Added the functions `murmurHash2_64`, `murmurHash3_32`, `murmurHash3_64`, and `murmurHash3_128` in addition to the existing `murmurHash2_32`. [#2791](https://github.com/ClickHouse/ClickHouse/pull/2791)
+-   Support for Nullable types in the ClickHouse ODBC driver (`ODBCDriver2` output format). [#2834](https://github.com/ClickHouse/ClickHouse/pull/2834)
+-   Support for `UUID` in the key columns.
+
+#### Improvements: {#improvements-5}
+
+-   Clusters can be removed without restarting the server when they are deleted from the config files. [#2777](https://github.com/ClickHouse/ClickHouse/pull/2777)
+-   External dictionaries can be removed without restarting the server when they are removed from config files. [#2779](https://github.com/ClickHouse/ClickHouse/pull/2779)
+-   Added `SETTINGS` support for the `Kafka` table engine. [Alexander Marshalov](https://github.com/ClickHouse/ClickHouse/pull/2781)
+-   Improvements for the `UUID` data type (not yet complete). [#2618](https://github.com/ClickHouse/ClickHouse/pull/2618)
+-   Support for empty parts after merges in the `SummingMergeTree`, `CollapsingMergeTree` and `VersionedCollapsingMergeTree` engines. [#2815](https://github.com/ClickHouse/ClickHouse/pull/2815)
+-   Old records of completed mutations are deleted (`ALTER DELETE`). [#2784](https://github.com/ClickHouse/ClickHouse/pull/2784)
+-   Added the `system.merge_tree_settings` table. [Kirill Shvakov](https://github.com/ClickHouse/ClickHouse/pull/2841)
+-   The `system.tables` table now has dependency columns: `dependencies_database` and `dependencies_table`. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2851)
+-   Added the `max_partition_size_to_drop` config option. [#2782](https://github.com/ClickHouse/ClickHouse/pull/2782)
+-   Added the `output_format_json_escape_forward_slashes` option. [Alexander Bocharov](https://github.com/ClickHouse/ClickHouse/pull/2812)
+-   Added the `max_fetch_partition_retries_count` setting. [#2831](https://github.com/ClickHouse/ClickHouse/pull/2831)
+-   Added the `prefer_localhost_replica` setting for disabling the preference for a local replica and going to a local replica without inter-process interaction. [#2832](https://github.com/ClickHouse/ClickHouse/pull/2832)
+-   The `quantileExact` aggregate function returns `nan` in the case of aggregation on an empty `Float32` or `Float64` set. [Sundy Li](https://github.com/ClickHouse/ClickHouse/pull/2855)
+
+#### Bug Fixes: {#bug-fixes-14}
+
+-   Removed unnecessary escaping of the connection string parameters for ODBC, which made it impossible to establish a connection. This error occurred in version 18.6.0.
+-   Fixed the logic for processing `REPLACE PARTITION` commands in the replication queue. If there are two `REPLACE` commands for the same partition, the incorrect logic could cause one of them to remain in the replication queue and not be executed. [#2814](https://github.com/ClickHouse/ClickHouse/pull/2814)
+-   Fixed a merge bug when all data parts were empty (parts that were formed from a merge or from `ALTER DELETE` if all data was deleted). This bug appeared in version 18.1.0. [#2930](https://github.com/ClickHouse/ClickHouse/pull/2930)
+-   Fixed an error for concurrent `Set` or `Join`. [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2823)
+-   Fixed the `Block structure mismatch in UNION stream: different number of columns` error that occurred for `UNION ALL` queries inside a sub-query if one of the `SELECT` queries contains duplicate column names. [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2094)
+-   Fixed a memory leak if an exception occurred when connecting to a MySQL server.
+-   Fixed incorrect clickhouse-client response code in case of a query error.
+-   Fixed incorrect behavior of materialized views containing DISTINCT. [#2795](https://github.com/ClickHouse/ClickHouse/issues/2795)
+
+#### Backward Incompatible Changes {#backward-incompatible-changes-4}
+
+-   Removed support for CHECK TABLE queries for Distributed tables.
+
+#### Build Changes: {#build-changes-3}
+
+-   The allocator has been replaced: `jemalloc` is now used instead of `tcmalloc`. In some scenarios, this increases speed up to 20%. However, there are queries that have slowed by up to 20%. Memory consumption has been reduced by approximately 10% in some scenarios, with improved stability. With highly competitive loads, CPU usage in userspace and in system shows just a slight increase. [#2773](https://github.com/ClickHouse/ClickHouse/pull/2773)
+-   Use of libressl from a submodule. [#1983](https://github.com/ClickHouse/ClickHouse/pull/1983) [#2807](https://github.com/ClickHouse/ClickHouse/pull/2807)
+-   Use of unixodbc from a submodule. [#2789](https://github.com/ClickHouse/ClickHouse/pull/2789)
+-   Use of mariadb-connector-c from a submodule. [#2785](https://github.com/ClickHouse/ClickHouse/pull/2785)
+-   Added functional test files to the repository that depend on the availability of test data (for the time being, without the test data itself).
+
+## ClickHouse Release 18.6 {#clickhouse-release-18-6}
+
+### ClickHouse Release 18.6.0, 2018-08-02 {#clickhouse-release-18-6-0-2018-08-02}
+
+#### New Features: {#new-features-6}
+
+-   Added support for ON expressions for the JOIN ON syntax:
+    `JOIN ON Expr([table.]column ...) = Expr([table.]column, ...) [AND Expr([table.]column, ...) = Expr([table.]column, ...) ...]`
+    The expression must be a chain of equalities joined by the AND operator. Each side of the equality can be an arbitrary expression over the columns of one of the tables. The use of fully qualified column names is supported (`table.name`, `database.table.name`, `table_alias.name`, `subquery_alias.name`) for the right table. [#2742](https://github.com/ClickHouse/ClickHouse/pull/2742)
+-   HTTPS can be enabled for replication. [#2760](https://github.com/ClickHouse/ClickHouse/pull/2760)
+
+#### Improvements: {#improvements-6}
+
+-   The server passes the patch component of its version to the client. Data about the patch version component is in `system.processes` and `query_log`. [#2646](https://github.com/ClickHouse/ClickHouse/pull/2646)
+
+## ClickHouse Release 18.5 {#clickhouse-release-18-5}
+
+### ClickHouse Release 18.5.1, 2018-07-31 {#clickhouse-release-18-5-1-2018-07-31}
+
+#### New Features: {#new-features-7}
+
+-   Added the hash function `murmurHash2_32` [#2756](https://github.com/ClickHouse/ClickHouse/pull/2756).
+
+#### Improvements: {#improvements-7}
+
+-   Now you can use the `from_env` [#2741](https://github.com/ClickHouse/ClickHouse/pull/2741) attribute to set values in config files from environment variables.
+-   Added case-insensitive versions of the `coalesce`, `ifNull`, and `nullIf functions` [#2752](https://github.com/ClickHouse/ClickHouse/pull/2752).
+
+#### Bug Fixes: {#bug-fixes-15}
+
+-   Fixed a possible bug when starting a replica [#2759](https://github.com/ClickHouse/ClickHouse/pull/2759).
+
+## ClickHouse Release 18.4 {#clickhouse-release-18-4}
+
+### ClickHouse Release 18.4.0, 2018-07-28 {#clickhouse-release-18-4-0-2018-07-28}
+
+#### New Features: {#new-features-8}
+
+-   Added system tables: `formats`, `data_type_families`, `aggregate_function_combinators`, `table_functions`, `table_engines`, `collations` [#2721](https://github.com/ClickHouse/ClickHouse/pull/2721).
+-   Added the ability to use a table function instead of a table as an argument of a `remote` or `cluster table function` [#2708](https://github.com/ClickHouse/ClickHouse/pull/2708).
+-   Support for `HTTP Basic` authentication in the replication protocol [#2727](https://github.com/ClickHouse/ClickHouse/pull/2727).
+-   The `has` function now allows searching for a numeric value in an array of `Enum` values [Maxim Khrisanfov](https://github.com/ClickHouse/ClickHouse/pull/2699).
+-   Support for adding arbitrary message separators when reading from `Kafka` [Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2701).
+
+#### Improvements: {#improvements-8}
+
+-   The `ALTER TABLE t DELETE WHERE` query does not rewrite data parts that were not affected by the WHERE condition [#2694](https://github.com/ClickHouse/ClickHouse/pull/2694).
+-   The `use_minimalistic_checksums_in_zookeeper` option for `ReplicatedMergeTree` tables is enabled by default. This setting was added in version 1.1.54378, 2018-04-16. Versions that are older than 1.1.54378 can no longer be installed.
+-   Support for running `KILL` and `OPTIMIZE` queries that specify `ON CLUSTER` [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2689).
+
+#### Bug Fixes: {#bug-fixes-16}
+
+-   Fixed the error `Column ... is not under an aggregate function and not in GROUP BY` for aggregation with an IN expression. This bug appeared in version 18.1.0. ([bbdd780b](https://github.com/ClickHouse/ClickHouse/commit/bbdd780be0be06a0f336775941cdd536878dd2c2))
+-   Fixed a bug in the `windowFunnel aggregate function` [Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2735).
+-   Fixed a bug in the `anyHeavy` aggregate function ([a2101df2](https://github.com/ClickHouse/ClickHouse/commit/a2101df25a6a0fba99aa71f8793d762af2b801ee))
+-   Fixed server crash when using the `countArray()` aggregate function.
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-5}
+
+-   Parameters for `Kafka` engine was changed from `Kafka(kafka_broker_list, kafka_topic_list, kafka_group_name, kafka_format[, kafka_schema, kafka_num_consumers])` to `Kafka(kafka_broker_list, kafka_topic_list, kafka_group_name, kafka_format[, kafka_row_delimiter, kafka_schema, kafka_num_consumers])`. If your tables use `kafka_schema` or `kafka_num_consumers` parameters, you have to manually edit the metadata files `path/metadata/database/table.sql` and add `kafka_row_delimiter` parameter with `''` value.
+
+## ClickHouse Release 18.1 {#clickhouse-release-18-1}
+
+### ClickHouse Release 18.1.0, 2018-07-23 {#clickhouse-release-18-1-0-2018-07-23}
+
+#### New Features: {#new-features-9}
+
+-   Support for the `ALTER TABLE t DELETE WHERE` query for non-replicated MergeTree tables ([#2634](https://github.com/ClickHouse/ClickHouse/pull/2634)).
+-   Support for arbitrary types for the `uniq*` family of aggregate functions ([#2010](https://github.com/ClickHouse/ClickHouse/issues/2010)).
+-   Support for arbitrary types in comparison operators ([#2026](https://github.com/ClickHouse/ClickHouse/issues/2026)).
+-   The `users.xml` file allows setting a subnet mask in the format `10.0.0.1/255.255.255.0`. This is necessary for using masks for IPv6 networks with zeros in the middle ([#2637](https://github.com/ClickHouse/ClickHouse/pull/2637)).
+-   Added the `arrayDistinct` function ([#2670](https://github.com/ClickHouse/ClickHouse/pull/2670)).
+-   The SummingMergeTree engine can now work with AggregateFunction type columns ([Constantin S. Pan](https://github.com/ClickHouse/ClickHouse/pull/2566)).
+
+#### Improvements: {#improvements-9}
+
+-   Changed the numbering scheme for release versions. Now the first part contains the year of release (A.D., Moscow timezone, minus 2000), the second part contains the number for major changes (increases for most releases), and the third part is the patch version. Releases are still backward compatible, unless otherwise stated in the changelog.
+-   Faster conversions of floating-point numbers to a string ([Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2664)).
+-   If some rows were skipped during an insert due to parsing errors (this is possible with the `input_allow_errors_num` and `input_allow_errors_ratio` settings enabled), the number of skipped rows is now written to the server log ([Leonardo Cecchi](https://github.com/ClickHouse/ClickHouse/pull/2669)).
+
+#### Bug Fixes: {#bug-fixes-17}
+
+-   Fixed the TRUNCATE command for temporary tables ([Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2624)).
+-   Fixed a rare deadlock in the ZooKeeper client library that occurred when there was a network error while reading the response ([c315200](https://github.com/ClickHouse/ClickHouse/commit/c315200e64b87e44bdf740707fc857d1fdf7e947)).
+-   Fixed an error during a CAST to Nullable types ([#1322](https://github.com/ClickHouse/ClickHouse/issues/1322)).
+-   Fixed the incorrect result of the `maxIntersection()` function when the boundaries of intervals coincided ([Michael Furmur](https://github.com/ClickHouse/ClickHouse/pull/2657)).
+-   Fixed incorrect transformation of the OR expression chain in a function argument ([chenxing-xc](https://github.com/ClickHouse/ClickHouse/pull/2663)).
+-   Fixed performance degradation for queries containing `IN (subquery)` expressions inside another subquery ([#2571](https://github.com/ClickHouse/ClickHouse/issues/2571)).
+-   Fixed incompatibility between servers with different versions in distributed queries that use a `CAST` function that isn’t in uppercase letters ([fe8c4d6](https://github.com/ClickHouse/ClickHouse/commit/fe8c4d64e434cacd4ceef34faa9005129f2190a5)).
+-   Added missing quoting of identifiers for queries to an external DBMS ([#2635](https://github.com/ClickHouse/ClickHouse/issues/2635)).
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-6}
+
+-   Converting a string containing the number zero to DateTime does not work. Example: `SELECT toDateTime('0')`. This is also the reason that `DateTime DEFAULT '0'` does not work in tables, as well as `<null_value>0</null_value>` in dictionaries. Solution: replace `0` with `0000-00-00 00:00:00`.
+
+## ClickHouse Release 1.1 {#clickhouse-release-1-1}
+
+### ClickHouse Release 1.1.54394, 2018-07-12 {#clickhouse-release-1-1-54394-2018-07-12}
+
+#### New Features: {#new-features-10}
+
+-   Added the `histogram` aggregate function ([Mikhail Surin](https://github.com/ClickHouse/ClickHouse/pull/2521)).
+-   Now `OPTIMIZE TABLE ... FINAL` can be used without specifying partitions for `ReplicatedMergeTree` ([Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2600)).
+
+#### Bug Fixes: {#bug-fixes-18}
+
+-   Fixed a problem with a very small timeout for sockets (one second) for reading and writing when sending and downloading replicated data, which made it impossible to download larger parts if there is a load on the network or disk (it resulted in cyclical attempts to download parts). This error occurred in version 1.1.54388.
+-   Fixed issues when using chroot in ZooKeeper if you inserted duplicate data blocks in the table.
+-   The `has` function now works correctly for an array with Nullable elements ([#2115](https://github.com/ClickHouse/ClickHouse/issues/2115)).
+-   The `system.tables` table now works correctly when used in distributed queries. The `metadata_modification_time` and `engine_full` columns are now non-virtual. Fixed an error that occurred if only these columns were queried from the table.
+-   Fixed how an empty `TinyLog` table works after inserting an empty data block ([#2563](https://github.com/ClickHouse/ClickHouse/issues/2563)).
+-   The `system.zookeeper` table works if the value of the node in ZooKeeper is NULL.
+
+### ClickHouse Release 1.1.54390, 2018-07-06 {#clickhouse-release-1-1-54390-2018-07-06}
+
+#### New Features: {#new-features-11}
+
+-   Queries can be sent in `multipart/form-data` format (in the `query` field), which is useful if external data is also sent for query processing ([Olga Hvostikova](https://github.com/ClickHouse/ClickHouse/pull/2490)).
+-   Added the ability to enable or disable processing single or double quotes when reading data in CSV format. You can configure this in the `format_csv_allow_single_quotes` and `format_csv_allow_double_quotes` settings ([Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2574)).
+-   Now `OPTIMIZE TABLE ... FINAL` can be used without specifying the partition for non-replicated variants of `MergeTree` ([Amos Bird](https://github.com/ClickHouse/ClickHouse/pull/2599)).
+
+#### Improvements: {#improvements-10}
+
+-   Improved performance, reduced memory consumption, and correct memory consumption tracking with use of the IN operator when a table index could be used ([#2584](https://github.com/ClickHouse/ClickHouse/pull/2584)).
+-   Removed redundant checking of checksums when adding a data part. This is important when there are a large number of replicas, because in these cases the total number of checks was equal to N^2.
+-   Added support for `Array(Tuple(...))` arguments for the `arrayEnumerateUniq` function ([#2573](https://github.com/ClickHouse/ClickHouse/pull/2573)).
+-   Added `Nullable` support for the `runningDifference` function ([#2594](https://github.com/ClickHouse/ClickHouse/pull/2594)).
+-   Improved query analysis performance when there is a very large number of expressions ([#2572](https://github.com/ClickHouse/ClickHouse/pull/2572)).
+-   Faster selection of data parts for merging in `ReplicatedMergeTree` tables. Faster recovery of the ZooKeeper session ([#2597](https://github.com/ClickHouse/ClickHouse/pull/2597)).
+-   The `format_version.txt` file for `MergeTree` tables is re-created if it is missing, which makes sense if ClickHouse is launched after copying the directory structure without files ([Ciprian Hacman](https://github.com/ClickHouse/ClickHouse/pull/2593)).
+
+#### Bug Fixes: {#bug-fixes-19}
+
+-   Fixed a bug when working with ZooKeeper that could make it impossible to recover the session and readonly states of tables before restarting the server.
+-   Fixed a bug when working with ZooKeeper that could result in old nodes not being deleted if the session is interrupted.
+-   Fixed an error in the `quantileTDigest` function for Float arguments (this bug was introduced in version 1.1.54388) ([Mikhail Surin](https://github.com/ClickHouse/ClickHouse/pull/2553)).
+-   Fixed a bug in the index for MergeTree tables if the primary key column is located inside the function for converting types between signed and unsigned integers of the same size ([#2603](https://github.com/ClickHouse/ClickHouse/pull/2603)).
+-   Fixed segfault if `macros` are used but they aren’t in the config file ([#2570](https://github.com/ClickHouse/ClickHouse/pull/2570)).
+-   Fixed switching to the default database when reconnecting the client ([#2583](https://github.com/ClickHouse/ClickHouse/pull/2583)).
+-   Fixed a bug that occurred when the `use_index_for_in_with_subqueries` setting was disabled.
+
+#### Security Fix: {#security-fix-1}
+
+-   Sending files is no longer possible when connected to MySQL (`LOAD DATA LOCAL INFILE`).
+
+### ClickHouse Release 1.1.54388, 2018-06-28 {#clickhouse-release-1-1-54388-2018-06-28}
+
+#### New Features: {#new-features-12}
+
+-   Support for the `ALTER TABLE t DELETE WHERE` query for replicated tables. Added the `system.mutations` table to track progress of this type of queries.
+-   Support for the `ALTER TABLE t [REPLACE|ATTACH] PARTITION` query for \*MergeTree tables.
+-   Support for the `TRUNCATE TABLE` query ([Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2260))
+-   Several new `SYSTEM` queries for replicated tables (`RESTART REPLICAS`, `SYNC REPLICA`, `[STOP|START] [MERGES|FETCHES|SENDS REPLICATED|REPLICATION QUEUES]`).
+-   Added the ability to write to a table with the MySQL engine and the corresponding table function ([sundy-li](https://github.com/ClickHouse/ClickHouse/pull/2294)).
+-   Added the `url()` table function and the `URL` table engine ([Alexander Sapin](https://github.com/ClickHouse/ClickHouse/pull/2501)).
+-   Added the `windowFunnel` aggregate function ([sundy-li](https://github.com/ClickHouse/ClickHouse/pull/2352)).
+-   New `startsWith` and `endsWith` functions for strings ([Vadim Plakhtinsky](https://github.com/ClickHouse/ClickHouse/pull/2429)).
+-   The `numbers()` table function now allows you to specify the offset ([Winter Zhang](https://github.com/ClickHouse/ClickHouse/pull/2535)).
+-   The password to `clickhouse-client` can be entered interactively.
+-   Server logs can now be sent to syslog ([Alexander Krasheninnikov](https://github.com/ClickHouse/ClickHouse/pull/2459)).
+-   Support for logging in dictionaries with a shared library source ([Alexander Sapin](https://github.com/ClickHouse/ClickHouse/pull/2472)).
+-   Support for custom CSV delimiters ([Ivan Zhukov](https://github.com/ClickHouse/ClickHouse/pull/2263))
+-   Added the `date_time_input_format` setting. If you switch this setting to `'best_effort'`, DateTime values will be read in a wide range of formats.
+-   Added the `clickhouse-obfuscator` utility for data obfuscation. Usage example: publishing data used in performance tests.
+
+#### Experimental Features: {#experimental-features-2}
+
+-   Added the ability to calculate `and` arguments only where they are needed ([Anastasia Tsarkova](https://github.com/ClickHouse/ClickHouse/pull/2272))
+-   JIT compilation to native code is now available for some expressions ([pyos](https://github.com/ClickHouse/ClickHouse/pull/2277)).
+
+#### Bug Fixes: {#bug-fixes-20}
+
+-   Duplicates no longer appear for a query with `DISTINCT` and `ORDER BY`.
+-   Queries with `ARRAY JOIN` and `arrayFilter` no longer return an incorrect result.
+-   Fixed an error when reading an array column from a Nested structure ([#2066](https://github.com/ClickHouse/ClickHouse/issues/2066)).
+-   Fixed an error when analyzing queries with a HAVING clause like `HAVING tuple IN (...)`.
+-   Fixed an error when analyzing queries with recursive aliases.
+-   Fixed an error when reading from ReplacingMergeTree with a condition in PREWHERE that filters all rows ([#2525](https://github.com/ClickHouse/ClickHouse/issues/2525)).
+-   User profile settings were not applied when using sessions in the HTTP interface.
+-   Fixed how settings are applied from the command line parameters in clickhouse-local.
+-   The ZooKeeper client library now uses the session timeout received from the server.
+-   Fixed a bug in the ZooKeeper client library when the client waited for the server response longer than the timeout.
+-   Fixed pruning of parts for queries with conditions on partition key columns ([#2342](https://github.com/ClickHouse/ClickHouse/issues/2342)).
+-   Merges are now possible after `CLEAR COLUMN IN PARTITION` ([#2315](https://github.com/ClickHouse/ClickHouse/issues/2315)).
+-   Type mapping in the ODBC table function has been fixed ([sundy-li](https://github.com/ClickHouse/ClickHouse/pull/2268)).
+-   Type comparisons have been fixed for `DateTime` with and without the time zone ([Alexander Bocharov](https://github.com/ClickHouse/ClickHouse/pull/2400)).
+-   Fixed syntactic parsing and formatting of the `CAST` operator.
+-   Fixed insertion into a materialized view for the Distributed table engine ([Babacar Diassé](https://github.com/ClickHouse/ClickHouse/pull/2411)).
+-   Fixed a race condition when writing data from the `Kafka` engine to materialized views ([Yangkuan Liu](https://github.com/ClickHouse/ClickHouse/pull/2448)).
+-   Fixed SSRF in the remote() table function.
+-   Fixed exit behavior of `clickhouse-client` in multiline mode ([#2510](https://github.com/ClickHouse/ClickHouse/issues/2510)).
+
+#### Improvements: {#improvements-11}
+
+-   Background tasks in replicated tables are now performed in a thread pool instead of in separate threads ([Silviu Caragea](https://github.com/ClickHouse/ClickHouse/pull/1722)).
+-   Improved LZ4 compression performance.
+-   Faster analysis for queries with a large number of JOINs and sub-queries.
+-   The DNS cache is now updated automatically when there are too many network errors.
+-   Table inserts no longer occur if the insert into one of the materialized views is not possible because it has too many parts.
+-   Corrected the discrepancy in the event counters `Query`, `SelectQuery`, and `InsertQuery`.
+-   Expressions like `tuple IN (SELECT tuple)` are allowed if the tuple types match.
+-   A server with replicated tables can start even if you haven’t configured ZooKeeper.
+-   When calculating the number of available CPU cores, limits on cgroups are now taken into account ([Atri Sharma](https://github.com/ClickHouse/ClickHouse/pull/2325)).
+-   Added chown for config directories in the systemd config file ([Mikhail Shiryaev](https://github.com/ClickHouse/ClickHouse/pull/2421)).
+
+#### Build Changes: {#build-changes-4}
+
+-   The gcc8 compiler can be used for builds.
+-   Added the ability to build llvm from submodule.
+-   The version of the librdkafka library has been updated to v0.11.4.
+-   Added the ability to use the system libcpuid library. The library version has been updated to 0.4.0.
+-   Fixed the build using the vectorclass library ([Babacar Diassé](https://github.com/ClickHouse/ClickHouse/pull/2274)).
+-   Cmake now generates files for ninja by default (like when using `-G Ninja`).
+-   Added the ability to use the libtinfo library instead of libtermcap ([Georgy Kondratiev](https://github.com/ClickHouse/ClickHouse/pull/2519)).
+-   Fixed a header file conflict in Fedora Rawhide ([#2520](https://github.com/ClickHouse/ClickHouse/issues/2520)).
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-7}
+
+-   Removed escaping in `Vertical` and `Pretty*` formats and deleted the `VerticalRaw` format.
+-   If servers with version 1.1.54388 (or newer) and servers with an older version are used simultaneously in a distributed query and the query has the `cast(x, 'Type')` expression without the `AS` keyword and does not have the word `cast` in uppercase, an exception will be thrown with a message like `Not found column cast(0, 'UInt8') in block`. Solution: Update the server on the entire cluster.
+
+### ClickHouse Release 1.1.54385, 2018-06-01 {#clickhouse-release-1-1-54385-2018-06-01}
+
+#### Bug Fixes: {#bug-fixes-21}
+
+-   Fixed an error that in some cases caused ZooKeeper operations to block.
+
+### ClickHouse Release 1.1.54383, 2018-05-22 {#clickhouse-release-1-1-54383-2018-05-22}
+
+#### Bug Fixes: {#bug-fixes-22}
+
+-   Fixed a slowdown of replication queue if a table has many replicas.
+
+### ClickHouse Release 1.1.54381, 2018-05-14 {#clickhouse-release-1-1-54381-2018-05-14}
+
+#### Bug Fixes: {#bug-fixes-23}
+
+-   Fixed a nodes leak in ZooKeeper when ClickHouse loses connection to ZooKeeper server.
+
+### ClickHouse Release 1.1.54380, 2018-04-21 {#clickhouse-release-1-1-54380-2018-04-21}
+
+#### New Features: {#new-features-13}
+
+-   Added the table function `file(path, format, structure)`. An example reading bytes from `/dev/urandom`: ``` ln -s /dev/urandom /var/lib/clickhouse/user_files/random``clickhouse-client -q "SELECT * FROM file('random', 'RowBinary', 'd UInt8') LIMIT 10" ```.
+
+#### Improvements: {#improvements-12}
+
+-   Subqueries can be wrapped in `()` brackets to enhance query readability. For example: `(SELECT 1) UNION ALL (SELECT 1)`.
+-   Simple `SELECT` queries from the `system.processes` table are not included in the `max_concurrent_queries` limit.
+
+#### Bug Fixes: {#bug-fixes-24}
+
+-   Fixed incorrect behavior of the `IN` operator when select from `MATERIALIZED VIEW`.
+-   Fixed incorrect filtering by partition index in expressions like `partition_key_column IN (...)`.
+-   Fixed inability to execute `OPTIMIZE` query on non-leader replica if `REANAME` was performed on the table.
+-   Fixed the authorization error when executing `OPTIMIZE` or `ALTER` queries on a non-leader replica.
+-   Fixed freezing of `KILL QUERY`.
+-   Fixed an error in ZooKeeper client library which led to loss of watches, freezing of distributed DDL queue, and slowdowns in the replication queue if a non-empty `chroot` prefix is used in the ZooKeeper configuration.
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-8}
+
+-   Removed support for expressions like `(a, b) IN (SELECT (a, b))` (you can use the equivalent expression `(a, b) IN (SELECT a, b)`). In previous releases, these expressions led to undetermined `WHERE` filtering or caused errors.
+
+### ClickHouse Release 1.1.54378, 2018-04-16 {#clickhouse-release-1-1-54378-2018-04-16}
+
+#### New Features: {#new-features-14}
+
+-   Logging level can be changed without restarting the server.
+-   Added the `SHOW CREATE DATABASE` query.
+-   The `query_id` can be passed to `clickhouse-client` (elBroom).
+-   New setting: `max_network_bandwidth_for_all_users`.
+-   Added support for `ALTER TABLE ... PARTITION ...` for `MATERIALIZED VIEW`.
+-   Added information about the size of data parts in uncompressed form in the system table.
+-   Server-to-server encryption support for distributed tables (`<secure>1</secure>` in the replica config in `<remote_servers>`).
+-   Configuration of the table level for the `ReplicatedMergeTree` family in order to minimize the amount of data stored in Zookeeper: : `use_minimalistic_checksums_in_zookeeper = 1`
+-   Configuration of the `clickhouse-client` prompt. By default, server names are now output to the prompt. The server’s display name can be changed. It’s also sent in the `X-ClickHouse-Display-Name` HTTP header (Kirill Shvakov).
+-   Multiple comma-separated `topics` can be specified for the `Kafka` engine (Tobias Adamson)
+-   When a query is stopped by `KILL QUERY` or `replace_running_query`, the client receives the `Query was canceled` exception instead of an incomplete result.
+
+#### Improvements: {#improvements-13}
+
+-   `ALTER TABLE ... DROP/DETACH PARTITION` queries are run at the front of the replication queue.
+-   `SELECT ... FINAL` and `OPTIMIZE ... FINAL` can be used even when the table has a single data part.
+-   A `query_log` table is recreated on the fly if it was deleted manually (Kirill Shvakov).
+-   The `lengthUTF8` function runs faster (zhang2014).
+-   Improved performance of synchronous inserts in `Distributed` tables (`insert_distributed_sync = 1`) when there is a very large number of shards.
+-   The server accepts the `send_timeout` and `receive_timeout` settings from the client and applies them when connecting to the client (they are applied in reverse order: the server socket’s `send_timeout` is set to the `receive_timeout` value received from the client, and vice versa).
+-   More robust crash recovery for asynchronous insertion into `Distributed` tables.
+-   The return type of the `countEqual` function changed from `UInt32` to `UInt64` (谢磊).
+
+#### Bug Fixes: {#bug-fixes-25}
+
+-   Fixed an error with `IN` when the left side of the expression is `Nullable`.
+-   Correct results are now returned when using tuples with `IN` when some of the tuple components are in the table index.
+-   The `max_execution_time` limit now works correctly with distributed queries.
+-   Fixed errors when calculating the size of composite columns in the `system.columns` table.
+-   Fixed an error when creating a temporary table `CREATE TEMPORARY TABLE IF NOT EXISTS.`
+-   Fixed errors in `StorageKafka` (##2075)
+-   Fixed server crashes from invalid arguments of certain aggregate functions.
+-   Fixed the error that prevented the `DETACH DATABASE` query from stopping background tasks for `ReplicatedMergeTree` tables.
+-   `Too many parts` state is less likely to happen when inserting into aggregated materialized views (##2084).
+-   Corrected recursive handling of substitutions in the config if a substitution must be followed by another substitution on the same level.
+-   Corrected the syntax in the metadata file when creating a `VIEW` that uses a query with `UNION ALL`.
+-   `SummingMergeTree` now works correctly for summation of nested data structures with a composite key.
+-   Fixed the possibility of a race condition when choosing the leader for `ReplicatedMergeTree` tables.
+
+#### Build Changes: {#build-changes-5}
+
+-   The build supports `ninja` instead of `make` and uses `ninja` by default for building releases.
+-   Renamed packages: `clickhouse-server-base` in `clickhouse-common-static`; `clickhouse-server-common` in `clickhouse-server`; `clickhouse-common-dbg` in `clickhouse-common-static-dbg`. To install, use `clickhouse-server clickhouse-client`. Packages with the old names will still load in the repositories for backward compatibility.
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-9}
+
+-   Removed the special interpretation of an IN expression if an array is specified on the left side. Previously, the expression `arr IN (set)` was interpreted as “at least one `arr` element belongs to the `set`”. To get the same behavior in the new version, write `arrayExists(x -> x IN (set), arr)`.
+-   Disabled the incorrect use of the socket option `SO_REUSEPORT`, which was incorrectly enabled by default in the Poco library. Note that on Linux there is no longer any reason to simultaneously specify the addresses `::` and `0.0.0.0` for listen – use just `::`, which allows listening to the connection both over IPv4 and IPv6 (with the default kernel config settings). You can also revert to the behavior from previous versions by specifying `<listen_reuse_port>1</listen_reuse_port>` in the config.
+
+### ClickHouse Release 1.1.54370, 2018-03-16 {#clickhouse-release-1-1-54370-2018-03-16}
+
+#### New Features: {#new-features-15}
+
+-   Added the `system.macros` table and auto updating of macros when the config file is changed.
+-   Added the `SYSTEM RELOAD CONFIG` query.
+-   Added the `maxIntersections(left_col, right_col)` aggregate function, which returns the maximum number of simultaneously intersecting intervals `[left; right]`. The `maxIntersectionsPosition(left, right)` function returns the beginning of the “maximum” interval. ([Michael Furmur](https://github.com/ClickHouse/ClickHouse/pull/2012)).
+
+#### Improvements: {#improvements-14}
+
+-   When inserting data in a `Replicated` table, fewer requests are made to `ZooKeeper` (and most of the user-level errors have disappeared from the `ZooKeeper` log).
+-   Added the ability to create aliases for data sets. Example: `WITH (1, 2, 3) AS set SELECT number IN set FROM system.numbers LIMIT 10`.
+
+#### Bug Fixes: {#bug-fixes-26}
+
+-   Fixed the `Illegal PREWHERE` error when reading from Merge tables for `Distributed`tables.
+-   Added fixes that allow you to start clickhouse-server in IPv4-only Docker containers.
+-   Fixed a race condition when reading from system `system.parts_columns tables.`
+-   Removed double buffering during a synchronous insert to a `Distributed` table, which could have caused the connection to timeout.
+-   Fixed a bug that caused excessively long waits for an unavailable replica before beginning a `SELECT` query.
+-   Fixed incorrect dates in the `system.parts` table.
+-   Fixed a bug that made it impossible to insert data in a `Replicated` table if `chroot` was non-empty in the configuration of the `ZooKeeper` cluster.
+-   Fixed the vertical merging algorithm for an empty `ORDER BY` table.
+-   Restored the ability to use dictionaries in queries to remote tables, even if these dictionaries are not present on the requestor server. This functionality was lost in release 1.1.54362.
+-   Restored the behavior for queries like `SELECT * FROM remote('server2', default.table) WHERE col IN (SELECT col2 FROM default.table)` when the right side of the `IN` should use a remote `default.table` instead of a local one. This behavior was broken in version 1.1.54358.
+-   Removed extraneous error-level logging of `Not found column ... in block`.
+
+### ClickHouse Release 1.1.54362, 2018-03-11 {#clickhouse-release-1-1-54362-2018-03-11}
+
+#### New Features: {#new-features-16}
+
+-   Aggregation without `GROUP BY` for an empty set (such as `SELECT count(*) FROM table WHERE 0`) now returns a result with one row with null values for aggregate functions, in compliance with the SQL standard. To restore the old behavior (return an empty result), set `empty_result_for_aggregation_by_empty_set` to 1.
+-   Added type conversion for `UNION ALL`. Different alias names are allowed in `SELECT` positions in `UNION ALL`, in compliance with the SQL standard.
+-   Arbitrary expressions are supported in `LIMIT BY` clauses. Previously, it was only possible to use columns resulting from `SELECT`.
+-   An index of `MergeTree` tables is used when `IN` is applied to a tuple of expressions from the columns of the primary key. Example: `WHERE (UserID, EventDate) IN ((123, '2000-01-01'), ...)` (Anastasiya Tsarkova).
+-   Added the `clickhouse-copier` tool for copying between clusters and resharding data (beta).
+-   Added consistent hashing functions: `yandexConsistentHash`, `jumpConsistentHash`, `sumburConsistentHash`. They can be used as a sharding key in order to reduce the amount of network traffic during subsequent reshardings.
+-   Added functions: `arrayAny`, `arrayAll`, `hasAny`, `hasAll`, `arrayIntersect`, `arrayResize`.
+-   Added the `arrayCumSum` function (Javi Santana).
+-   Added the `parseDateTimeBestEffort`, `parseDateTimeBestEffortOrZero`, and `parseDateTimeBestEffortOrNull` functions to read the DateTime from a string containing text in a wide variety of possible formats.
+-   Data can be partially reloaded from external dictionaries during updating (load just the records in which the value of the specified field greater than in the previous download) (Arsen Hakobyan).
+-   Added the `cluster` table function. Example: `cluster(cluster_name, db, table)`. The `remote` table function can accept the cluster name as the first argument, if it is specified as an identifier.
+-   The `remote` and `cluster` table functions can be used in `INSERT` queries.
+-   Added the `create_table_query` and `engine_full` virtual columns to the `system.tables`table . The `metadata_modification_time` column is virtual.
+-   Added the `data_path` and `metadata_path` columns to `system.tables`and`system.databases` tables, and added the `path` column to the `system.parts` and `system.parts_columns` tables.
+-   Added additional information about merges in the `system.part_log` table.
+-   An arbitrary partitioning key can be used for the `system.query_log` table (Kirill Shvakov).
+-   The `SHOW TABLES` query now also shows temporary tables. Added temporary tables and the `is_temporary` column to `system.tables` (zhang2014).
+-   Added `DROP TEMPORARY TABLE` and `EXISTS TEMPORARY TABLE` queries (zhang2014).
+-   Support for `SHOW CREATE TABLE` for temporary tables (zhang2014).
+-   Added the `system_profile` configuration parameter for the settings used by internal processes.
+-   Support for loading `object_id` as an attribute in `MongoDB` dictionaries (Pavel Litvinenko).
+-   Reading `null` as the default value when loading data for an external dictionary with the `MongoDB` source (Pavel Litvinenko).
+-   Reading `DateTime` values in the `Values` format from a Unix timestamp without single quotes.
+-   Failover is supported in `remote` table functions for cases when some of the replicas are missing the requested table.
+-   Configuration settings can be overridden in the command line when you run `clickhouse-server`. Example: `clickhouse-server -- --logger.level=information`.
+-   Implemented the `empty` function from a `FixedString` argument: the function returns 1 if the string consists entirely of null bytes (zhang2014).
+-   Added the `listen_try`configuration parameter for listening to at least one of the listen addresses without quitting, if some of the addresses can’t be listened to (useful for systems with disabled support for IPv4 or IPv6).
+-   Added the `VersionedCollapsingMergeTree` table engine.
+-   Support for rows and arbitrary numeric types for the `library` dictionary source.
+-   `MergeTree` tables can be used without a primary key (you need to specify `ORDER BY tuple()`).
+-   A `Nullable` type can be `CAST` to a non-`Nullable` type if the argument is not `NULL`.
+-   `RENAME TABLE` can be performed for `VIEW`.
+-   Added the `throwIf` function.
+-   Added the `odbc_default_field_size` option, which allows you to extend the maximum size of the value loaded from an ODBC source (by default, it is 1024).
+-   The `system.processes` table and `SHOW PROCESSLIST` now have the `is_cancelled` and `peak_memory_usage` columns.
+
+#### Improvements: {#improvements-15}
+
+-   Limits and quotas on the result are no longer applied to intermediate data for `INSERT SELECT` queries or for `SELECT` subqueries.
+-   Fewer false triggers of `force_restore_data` when checking the status of `Replicated` tables when the server starts.
+-   Added the `allow_distributed_ddl` option.
+-   Nondeterministic functions are not allowed in expressions for `MergeTree` table keys.
+-   Files with substitutions from `config.d` directories are loaded in alphabetical order.
+-   Improved performance of the `arrayElement` function in the case of a constant multidimensional array with an empty array as one of the elements. Example: `[[1], []][x]`.
+-   The server starts faster now when using configuration files with very large substitutions (for instance, very large lists of IP networks).
+-   When running a query, table valued functions run once. Previously, `remote` and `mysql` table valued functions performed the same query twice to retrieve the table structure from a remote server.
+-   The `MkDocs` documentation generator is used.
+-   When you try to delete a table column that `DEFAULT`/`MATERIALIZED` expressions of other columns depend on, an exception is thrown (zhang2014).
+-   Added the ability to parse an empty line in text formats as the number 0 for `Float` data types. This feature was previously available but was lost in release 1.1.54342.
+-   `Enum` values can be used in `min`, `max`, `sum` and some other functions. In these cases, it uses the corresponding numeric values. This feature was previously available but was lost in the release 1.1.54337.
+-   Added `max_expanded_ast_elements` to restrict the size of the AST after recursively expanding aliases.
+
+#### Bug Fixes: {#bug-fixes-27}
+
+-   Fixed cases when unnecessary columns were removed from subqueries in error, or not removed from subqueries containing `UNION ALL`.
+-   Fixed a bug in merges for `ReplacingMergeTree` tables.
+-   Fixed synchronous insertions in `Distributed` tables (`insert_distributed_sync = 1`).
+-   Fixed segfault for certain uses of `FULL` and `RIGHT JOIN` with duplicate columns in subqueries.
+-   Fixed segfault for certain uses of `replace_running_query` and `KILL QUERY`.
+-   Fixed the order of the `source` and `last_exception` columns in the `system.dictionaries` table.
+-   Fixed a bug when the `DROP DATABASE` query did not delete the file with metadata.
+-   Fixed the `DROP DATABASE` query for `Dictionary` databases.
+-   Fixed the low precision of `uniqHLL12` and `uniqCombined` functions for cardinalities greater than 100 million items (Alex Bocharov).
+-   Fixed the calculation of implicit default values when necessary to simultaneously calculate default explicit expressions in `INSERT` queries (zhang2014).
+-   Fixed a rare case when a query to a `MergeTree` table couldn’t finish (chenxing-xc).
+-   Fixed a crash that occurred when running a `CHECK` query for `Distributed` tables if all shards are local (chenxing.xc).
+-   Fixed a slight performance regression with functions that use regular expressions.
+-   Fixed a performance regression when creating multidimensional arrays from complex expressions.
+-   Fixed a bug that could cause an extra `FORMAT` section to appear in an `.sql` file with metadata.
+-   Fixed a bug that caused the `max_table_size_to_drop` limit to apply when trying to delete a `MATERIALIZED VIEW` looking at an explicitly specified table.
+-   Fixed incompatibility with old clients (old clients were sometimes sent data with the `DateTime('timezone')` type, which they do not understand).
+-   Fixed a bug when reading `Nested` column elements of structures that were added using `ALTER` but that are empty for the old partitions, when the conditions for these columns moved to `PREWHERE`.
+-   Fixed a bug when filtering tables by virtual `_table` columns in queries to `Merge` tables.
+-   Fixed a bug when using `ALIAS` columns in `Distributed` tables.
+-   Fixed a bug that made dynamic compilation impossible for queries with aggregate functions from the `quantile` family.
+-   Fixed a race condition in the query execution pipeline that occurred in very rare cases when using `Merge` tables with a large number of tables, and when using `GLOBAL` subqueries.
+-   Fixed a crash when passing arrays of different sizes to an `arrayReduce` function when using aggregate functions from multiple arguments.
+-   Prohibited the use of queries with `UNION ALL` in a `MATERIALIZED VIEW`.
+-   Fixed an error during initialization of the `part_log` system table when the server starts (by default, `part_log` is disabled).
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-10}
+
+-   Removed the `distributed_ddl_allow_replicated_alter` option. This behavior is enabled by default.
+-   Removed the `strict_insert_defaults` setting. If you were using this functionality, write to `feedback@clickhouse.com`.
+-   Removed the `UnsortedMergeTree` engine.
+
+### ClickHouse Release 1.1.54343, 2018-02-05 {#clickhouse-release-1-1-54343-2018-02-05}
+
+-   Added macros support for defining cluster names in distributed DDL queries and constructors of Distributed tables: `CREATE TABLE distr ON CLUSTER '{cluster}' (...) ENGINE = Distributed('{cluster}', 'db', 'table')`.
+-   Now queries like `SELECT ... FROM table WHERE expr IN (subquery)` are processed using the `table` index.
+-   Improved processing of duplicates when inserting to Replicated tables, so they no longer slow down execution of the replication queue.
+
+### ClickHouse Release 1.1.54342, 2018-01-22 {#clickhouse-release-1-1-54342-2018-01-22}
+
+This release contains bug fixes for the previous release 1.1.54337:
+
+-   Fixed a regression in 1.1.54337: if the default user has readonly access, then the server refuses to start up with the message `Cannot create database in readonly mode`.
+-   Fixed a regression in 1.1.54337: on systems with systemd, logs are always written to syslog regardless of the configuration; the watchdog script still uses init.d.
+-   Fixed a regression in 1.1.54337: wrong default configuration in the Docker image.
+-   Fixed nondeterministic behavior of GraphiteMergeTree (you can see it in log messages `Data after merge is not byte-identical to the data on another replicas`).
+-   Fixed a bug that may lead to inconsistent merges after OPTIMIZE query to Replicated tables (you may see it in log messages `Part ... intersects the previous part`).
+-   Buffer tables now work correctly when MATERIALIZED columns are present in the destination table (by zhang2014).
+-   Fixed a bug in implementation of NULL.
+
+### ClickHouse Release 1.1.54337, 2018-01-18 {#clickhouse-release-1-1-54337-2018-01-18}
+
+#### New Features: {#new-features-17}
+
+-   Added support for storage of multi-dimensional arrays and tuples (`Tuple` data type) in tables.
+-   Support for table functions for `DESCRIBE` and `INSERT` queries. Added support for subqueries in `DESCRIBE`. Examples: `DESC TABLE remote('host', default.hits)`; `DESC TABLE (SELECT 1)`; `INSERT INTO TABLE FUNCTION remote('host', default.hits)`. Support for `INSERT INTO TABLE` in addition to `INSERT INTO`.
+-   Improved support for time zones. The `DateTime` data type can be annotated with the timezone that is used for parsing and formatting in text formats. Example: `DateTime('Asia/Istanbul')`. When timezones are specified in functions for `DateTime` arguments, the return type will track the timezone, and the value will be displayed as expected.
+-   Added the functions `toTimeZone`, `timeDiff`, `toQuarter`, `toRelativeQuarterNum`. The `toRelativeHour`/`Minute`/`Second` functions can take a value of type `Date` as an argument. The `now` function name is case-sensitive.
+-   Added the `toStartOfFifteenMinutes` function (Kirill Shvakov).
+-   Added the `clickhouse format` tool for formatting queries.
+-   Added the `format_schema_path` configuration parameter (Marek Vavruşa). It is used for specifying a schema in `Cap'n Proto` format. Schema files can be located only in the specified directory.
+-   Added support for config substitutions (`incl` and `conf.d`) for configuration of external dictionaries and models (Pavel Yakunin).
+-   Added a column with documentation for the `system.settings` table (Kirill Shvakov).
+-   Added the `system.parts_columns` table with information about column sizes in each data part of `MergeTree` tables.
+-   Added the `system.models` table with information about loaded `CatBoost` machine learning models.
+-   Added the `mysql` and `odbc` table function and corresponding `MySQL` and `ODBC` table engines for accessing remote databases. This functionality is in the beta stage.
+-   Added the possibility to pass an argument of type `AggregateFunction` for the `groupArray` aggregate function (so you can create an array of states of some aggregate function).
+-   Removed restrictions on various combinations of aggregate function combinators. For example, you can use `avgForEachIf` as well as `avgIfForEach` aggregate functions, which have different behaviors.
+-   The `-ForEach` aggregate function combinator is extended for the case of aggregate functions of multiple arguments.
+-   Added support for aggregate functions of `Nullable` arguments even for cases when the function returns a non-`Nullable` result (added with the contribution of Silviu Caragea). Example: `groupArray`, `groupUniqArray`, `topK`.
+-   Added the `max_client_network_bandwidth` for `clickhouse-client` (Kirill Shvakov).
+-   Users with the `readonly = 2` setting are allowed to work with TEMPORARY tables (CREATE, DROP, INSERT…) (Kirill Shvakov).
+-   Added support for using multiple consumers with the `Kafka` engine. Extended configuration options for `Kafka` (Marek Vavruša).
+-   Added the `intExp3` and `intExp4` functions.
+-   Added the `sumKahan` aggregate function.
+-   Added the to \* Number\* OrNull functions, where \* Number\* is a numeric type.
+-   Added support for `WITH` clauses for an `INSERT SELECT` query (author: zhang2014).
+-   Added settings: `http_connection_timeout`, `http_send_timeout`, `http_receive_timeout`. In particular, these settings are used for downloading data parts for replication. Changing these settings allows for faster failover if the network is overloaded.
+-   Added support for `ALTER` for tables of type `Null` (Anastasiya Tsarkova).
+-   The `reinterpretAsString` function is extended for all data types that are stored contiguously in memory.
+-   Added the `--silent` option for the `clickhouse-local` tool. It suppresses printing query execution info in stderr.
+-   Added support for reading values of type `Date` from text in a format where the month and/or day of the month is specified using a single digit instead of two digits (Amos Bird).
+
+#### Performance Optimizations: {#performance-optimizations}
+
+-   Improved performance of aggregate functions `min`, `max`, `any`, `anyLast`, `anyHeavy`, `argMin`, `argMax` from string arguments.
+-   Improved performance of the functions `isInfinite`, `isFinite`, `isNaN`, `roundToExp2`.
+-   Improved performance of parsing and formatting `Date` and `DateTime` type values in text format.
+-   Improved performance and precision of parsing floating point numbers.
+-   Lowered memory usage for `JOIN` in the case when the left and right parts have columns with identical names that are not contained in `USING` .
+-   Improved performance of aggregate functions `varSamp`, `varPop`, `stddevSamp`, `stddevPop`, `covarSamp`, `covarPop`, `corr` by reducing computational stability. The old functions are available under the names `varSampStable`, `varPopStable`, `stddevSampStable`, `stddevPopStable`, `covarSampStable`, `covarPopStable`, `corrStable`.
+
+#### Bug Fixes: {#bug-fixes-28}
+
+-   Fixed data deduplication after running a `DROP` or `DETACH PARTITION` query. In the previous version, dropping a partition and inserting the same data again was not working because inserted blocks were considered duplicates.
+-   Fixed a bug that could lead to incorrect interpretation of the `WHERE` clause for `CREATE MATERIALIZED VIEW` queries with `POPULATE` .
+-   Fixed a bug in using the `root_path` parameter in the `zookeeper_servers` configuration.
+-   Fixed unexpected results of passing the `Date` argument to `toStartOfDay` .
+-   Fixed the `addMonths` and `subtractMonths` functions and the arithmetic for `INTERVAL n MONTH` in cases when the result has the previous year.
+-   Added missing support for the `UUID` data type for `DISTINCT` , `JOIN` , and `uniq` aggregate functions and external dictionaries (Evgeniy Ivanov). Support for `UUID` is still incomplete.
+-   Fixed `SummingMergeTree` behavior in cases when the rows summed to zero.
+-   Various fixes for the `Kafka` engine (Marek Vavruša).
+-   Fixed incorrect behavior of the `Join` table engine (Amos Bird).
+-   Fixed incorrect allocator behavior under FreeBSD and OS X.
+-   The `extractAll` function now supports empty matches.
+-   Fixed an error that blocked usage of `libressl` instead of `openssl` .
+-   Fixed the `CREATE TABLE AS SELECT` query from temporary tables.
+-   Fixed non-atomicity of updating the replication queue. This could lead to replicas being out of sync until the server restarts.
+-   Fixed possible overflow in `gcd` , `lcm` and `modulo` (`%` operator) (Maks Skorokhod).
+-   `-preprocessed` files are now created after changing `umask` (`umask` can be changed in the config).
+-   Fixed a bug in the background check of parts (`MergeTreePartChecker` ) when using a custom partition key.
+-   Fixed parsing of tuples (values of the `Tuple` data type) in text formats.
+-   Improved error messages about incompatible types passed to `multiIf` , `array` and some other functions.
+-   Redesigned support for `Nullable` types. Fixed bugs that may lead to a server crash. Fixed almost all other bugs related to `NULL` support: incorrect type conversions in INSERT SELECT, insufficient support for Nullable in HAVING and PREWHERE, `join_use_nulls` mode, Nullable types as arguments of `OR` operator, etc.
+-   Fixed various bugs related to internal semantics of data types. Examples: unnecessary summing of `Enum` type fields in `SummingMergeTree` ; alignment of `Enum` types in `Pretty` formats, etc.
+-   Stricter checks for allowed combinations of composite columns.
+-   Fixed the overflow when specifying a very large parameter for the `FixedString` data type.
+-   Fixed a bug in the `topK` aggregate function in a generic case.
+-   Added the missing check for equality of array sizes in arguments of n-ary variants of aggregate functions with an `-Array` combinator.
+-   Fixed a bug in `--pager` for `clickhouse-client` (author: ks1322).
+-   Fixed the precision of the `exp10` function.
+-   Fixed the behavior of the `visitParamExtract` function for better compliance with documentation.
+-   Fixed the crash when incorrect data types are specified.
+-   Fixed the behavior of `DISTINCT` in the case when all columns are constants.
+-   Fixed query formatting in the case of using the `tupleElement` function with a complex constant expression as the tuple element index.
+-   Fixed a bug in `Dictionary` tables for `range_hashed` dictionaries.
+-   Fixed a bug that leads to excessive rows in the result of `FULL` and `RIGHT JOIN` (Amos Bird).
+-   Fixed a server crash when creating and removing temporary files in `config.d` directories during config reload.
+-   Fixed the `SYSTEM DROP DNS CACHE` query: the cache was flushed but addresses of cluster nodes were not updated.
+-   Fixed the behavior of `MATERIALIZED VIEW` after executing `DETACH TABLE` for the table under the view (Marek Vavruša).
+
+#### Build Improvements: {#build-improvements-4}
+
+-   The `pbuilder` tool is used for builds. The build process is almost completely independent of the build host environment.
+-   A single build is used for different OS versions. Packages and binaries have been made compatible with a wide range of Linux systems.
+-   Added the `clickhouse-test` package. It can be used to run functional tests.
+-   The source tarball can now be published to the repository. It can be used to reproduce the build without using GitHub.
+-   Added limited integration with Travis CI. Due to limits on build time in Travis, only the debug build is tested and a limited subset of tests are run.
+-   Added support for `Cap'n'Proto` in the default build.
+-   Changed the format of documentation sources from `Restricted Text` to `Markdown`.
+-   Added support for `systemd` (Vladimir Smirnov). It is disabled by default due to incompatibility with some OS images and can be enabled manually.
+-   For dynamic code generation, `clang` and `lld` are embedded into the `clickhouse` binary. They can also be invoked as `clickhouse clang` and `clickhouse lld` .
+-   Removed usage of GNU extensions from the code. Enabled the `-Wextra` option. When building with `clang` the default is `libc++` instead of `libstdc++`.
+-   Extracted `clickhouse_parsers` and `clickhouse_common_io` libraries to speed up builds of various tools.
+
+#### Backward Incompatible Changes: {#backward-incompatible-changes-11}
+
+-   The format for marks in `Log` type tables that contain `Nullable` columns was changed in a backward incompatible way. If you have these tables, you should convert them to the `TinyLog` type before starting up the new server version. To do this, replace `ENGINE = Log` with `ENGINE = TinyLog` in the corresponding `.sql` file in the `metadata` directory. If your table does not have `Nullable` columns or if the type of your table is not `Log`, then you do not need to do anything.
+-   Removed the `experimental_allow_extended_storage_definition_syntax` setting. Now this feature is enabled by default.
+-   The `runningIncome` function was renamed to `runningDifferenceStartingWithFirstvalue` to avoid confusion.
+-   Removed the `FROM ARRAY JOIN arr` syntax when ARRAY JOIN is specified directly after FROM with no table (Amos Bird).
+-   Removed the `BlockTabSeparated` format that was used solely for demonstration purposes.
+-   Changed the state format for aggregate functions `varSamp`, `varPop`, `stddevSamp`, `stddevPop`, `covarSamp`, `covarPop`, `corr`. If you have stored states of these aggregate functions in tables (using the `AggregateFunction` data type or materialized views with corresponding states), please write to feedback@clickhouse.com.
+-   In previous server versions there was an undocumented feature: if an aggregate function depends on parameters, you can still specify it without parameters in the AggregateFunction data type. Example: `AggregateFunction(quantiles, UInt64)` instead of `AggregateFunction(quantiles(0.5, 0.9), UInt64)`. This feature was lost. Although it was undocumented, we plan to support it again in future releases.
+-   Enum data types cannot be used in min/max aggregate functions. This ability will be returned in the next release.
+
+#### Please Note When Upgrading: {#please-note-when-upgrading}
+
+-   When doing a rolling update on a cluster, at the point when some of the replicas are running the old version of ClickHouse and some are running the new version, replication is temporarily stopped and the message `unknown parameter 'shard'` appears in the log. Replication will continue after all replicas of the cluster are updated.
+-   If different versions of ClickHouse are running on the cluster servers, it is possible that distributed queries using the following functions will have incorrect results: `varSamp`, `varPop`, `stddevSamp`, `stddevPop`, `covarSamp`, `covarPop`, `corr`. You should update all cluster nodes.
+
+## [Changelog for 2017](../../whats-new/changelog/2017.md#clickhouse-release-1-1-54327-2017-12-21) {#changelog-for-2017}
diff --git a/docs/en/reference/whats-new/changelog/2019.md b/docs/en/reference/whats-new/changelog/2019.md
new file mode 100644
index 00000000000..aa06f5cb1e3
--- /dev/null
+++ b/docs/en/reference/whats-new/changelog/2019.md
@@ -0,0 +1,2072 @@
+---
+toc_priority: 77
+toc_title: '2019'
+---
+
+## ClickHouse Release 19.17 {#clickhouse-release-v19-17}
+
+### ClickHouse Release 19.17.6.36, 2019-12-27 {#clickhouse-release-v19-17-6-36-2019-12-27}
+
+#### Bug Fix {#bug-fix}
+
+-   Fixed potential buffer overflow in decompress. Malicious user can pass fabricated compressed data that could cause read after buffer. This issue was found by Eldar Zaitov from Yandex information security team. [#8404](https://github.com/ClickHouse/ClickHouse/pull/8404) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed possible server crash (`std::terminate`) when the server cannot send or write data in JSON or XML format with values of String data type (that require UTF-8 validation) or when compressing result data with Brotli algorithm or in some other rare cases. [#8384](https://github.com/ClickHouse/ClickHouse/pull/8384) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed dictionaries with source from a clickhouse `VIEW`, now reading such dictionaries does not cause the error `There is no query`. [#8351](https://github.com/ClickHouse/ClickHouse/pull/8351) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fixed checking if a client host is allowed by host_regexp specified in users.xml. [#8241](https://github.com/ClickHouse/ClickHouse/pull/8241), [#8342](https://github.com/ClickHouse/ClickHouse/pull/8342) ([Vitaly Baranov](https://github.com/vitlibar))
+-   `RENAME TABLE` for a distributed table now renames the folder containing inserted data before sending to shards. This fixes an issue with successive renames `tableA->tableB`, `tableC->tableA`. [#8306](https://github.com/ClickHouse/ClickHouse/pull/8306) ([tavplubix](https://github.com/tavplubix))
+-   `range_hashed` external dictionaries created by DDL queries now allow ranges of arbitrary numeric types. [#8275](https://github.com/ClickHouse/ClickHouse/pull/8275) ([alesapin](https://github.com/alesapin))
+-   Fixed `INSERT INTO table SELECT ... FROM mysql(...)` table function. [#8234](https://github.com/ClickHouse/ClickHouse/pull/8234) ([tavplubix](https://github.com/tavplubix))
+-   Fixed segfault in `INSERT INTO TABLE FUNCTION file()` while inserting into a file which does not exist. Now in this case file would be created and then insert would be processed. [#8177](https://github.com/ClickHouse/ClickHouse/pull/8177) ([Olga Khvostikova](https://github.com/stavrolia))
+-   Fixed bitmapAnd error when intersecting an aggregated bitmap and a scalar bitmap. [#8082](https://github.com/ClickHouse/ClickHouse/pull/8082) ([Yue Huang](https://github.com/moon03432))
+-   Fixed segfault when `EXISTS` query was used without `TABLE` or `DICTIONARY` qualifier, just like `EXISTS t`. [#8213](https://github.com/ClickHouse/ClickHouse/pull/8213) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed return type for functions `rand` and `randConstant` in case of nullable argument. Now functions always return `UInt32` and never `Nullable(UInt32)`. [#8204](https://github.com/ClickHouse/ClickHouse/pull/8204) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fixed `DROP DICTIONARY IF EXISTS db.dict`, now it does not throw exception if `db` does not exist. [#8185](https://github.com/ClickHouse/ClickHouse/pull/8185) ([Vitaly Baranov](https://github.com/vitlibar))
+-   If a table wasn’t completely dropped because of server crash, the server will try to restore and load it [#8176](https://github.com/ClickHouse/ClickHouse/pull/8176) ([tavplubix](https://github.com/tavplubix))
+-   Fixed a trivial count query for a distributed table if there are more than two shard local table. [#8164](https://github.com/ClickHouse/ClickHouse/pull/8164) ([小路](https://github.com/nicelulu))
+-   Fixed bug that lead to a data race in DB::BlockStreamProfileInfo::calculateRowsBeforeLimit() [#8143](https://github.com/ClickHouse/ClickHouse/pull/8143) ([Alexander Kazakov](https://github.com/Akazz))
+-   Fixed `ALTER table MOVE part` executed immediately after merging the specified part, which could cause moving a part which the specified part merged into. Now it correctly moves the specified part. [#8104](https://github.com/ClickHouse/ClickHouse/pull/8104) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Expressions for dictionaries can be specified as strings now. This is useful for calculation of attributes while extracting data from non-ClickHouse sources because it allows to use non-ClickHouse syntax for those expressions. [#8098](https://github.com/ClickHouse/ClickHouse/pull/8098) ([alesapin](https://github.com/alesapin))
+-   Fixed a very rare race in `clickhouse-copier` because of an overflow in ZXid. [#8088](https://github.com/ClickHouse/ClickHouse/pull/8088) ([Ding Xiang Fei](https://github.com/dingxiangfei2009))
+-   Fixed the bug when after the query failed (due to “Too many simultaneous queries” for example) it would not read external tables info, and the
+    next request would interpret this info as the beginning of the next query causing an error like `Unknown packet from client`. [#8084](https://github.com/ClickHouse/ClickHouse/pull/8084) ([Azat Khuzhin](https://github.com/azat))
+-   Avoid null dereference after “Unknown packet X from server” [#8071](https://github.com/ClickHouse/ClickHouse/pull/8071) ([Azat Khuzhin](https://github.com/azat))
+-   Restore support of all ICU locales, add the ability to apply collations for constant expressions and add language name to system.collations table. [#8051](https://github.com/ClickHouse/ClickHouse/pull/8051) ([alesapin](https://github.com/alesapin))
+-   Number of streams for read from `StorageFile` and `StorageHDFS` is now limited, to avoid exceeding the memory limit. [#7981](https://github.com/ClickHouse/ClickHouse/pull/7981) ([alesapin](https://github.com/alesapin))
+-   Fixed `CHECK TABLE` query for `*MergeTree` tables without key. [#7979](https://github.com/ClickHouse/ClickHouse/pull/7979) ([alesapin](https://github.com/alesapin))
+-   Removed the mutation number from a part name in case there were no mutations. This removing improved the compatibility with older versions. [#8250](https://github.com/ClickHouse/ClickHouse/pull/8250) ([alesapin](https://github.com/alesapin))
+-   Fixed the bug that mutations are skipped for some attached parts due to their data_version are larger than the table mutation version. [#7812](https://github.com/ClickHouse/ClickHouse/pull/7812) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Allow starting the server with redundant copies of parts after moving them to another device. [#7810](https://github.com/ClickHouse/ClickHouse/pull/7810) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Fixed the error “Sizes of columns does not match” that might appear when using aggregate function columns. [#7790](https://github.com/ClickHouse/ClickHouse/pull/7790) ([Boris Granveaud](https://github.com/bgranvea))
+-   Now an exception will be thrown in case of using WITH TIES alongside LIMIT BY. And now it’s possible to use TOP with LIMIT BY. [#7637](https://github.com/ClickHouse/ClickHouse/pull/7637) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+-   Fix dictionary reload if it has `invalidate_query`, which stopped updates and some exception on previous update tries. [#8029](https://github.com/ClickHouse/ClickHouse/pull/8029) ([alesapin](https://github.com/alesapin))
+
+### ClickHouse Release 19.17.4.11, 2019-11-22 {#clickhouse-release-v19-17-4-11-2019-11-22}
+
+#### Backward Incompatible Change {#backward-incompatible-change}
+
+-   Using column instead of AST to store scalar subquery results for better performance. Setting `enable_scalar_subquery_optimization` was added in 19.17 and it was enabled by default. It leads to errors like [this](https://github.com/ClickHouse/ClickHouse/issues/7851) during upgrade to 19.17.2 or 19.17.3 from previous versions. This setting was disabled by default in 19.17.4, to make possible upgrading from 19.16 and older versions without errors. [#7392](https://github.com/ClickHouse/ClickHouse/pull/7392) ([Amos Bird](https://github.com/amosbird))
+
+#### New Feature {#new-feature}
+
+-   Add the ability to create dictionaries with DDL queries. [#7360](https://github.com/ClickHouse/ClickHouse/pull/7360) ([alesapin](https://github.com/alesapin))
+-   Make `bloom_filter` type of index supporting `LowCardinality` and `Nullable` [#7363](https://github.com/ClickHouse/ClickHouse/issues/7363) [#7561](https://github.com/ClickHouse/ClickHouse/pull/7561) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Add function `isValidJSON` to check that passed string is a valid json. [#5910](https://github.com/ClickHouse/ClickHouse/issues/5910) [#7293](https://github.com/ClickHouse/ClickHouse/pull/7293) ([Vdimir](https://github.com/Vdimir))
+-   Implement `arrayCompact` function [#7328](https://github.com/ClickHouse/ClickHouse/pull/7328) ([Memo](https://github.com/Joeywzr))
+-   Created function `hex` for Decimal numbers. It works like `hex(reinterpretAsString())`, but does not delete last zero bytes. [#7355](https://github.com/ClickHouse/ClickHouse/pull/7355) ([Mikhail Korotov](https://github.com/millb))
+-   Add `arrayFill` and `arrayReverseFill` functions, which replace elements by other elements in front/back of them in the array. [#7380](https://github.com/ClickHouse/ClickHouse/pull/7380) ([hcz](https://github.com/hczhcz))
+-   Add `CRC32IEEE()`/`CRC64()` support [#7480](https://github.com/ClickHouse/ClickHouse/pull/7480) ([Azat Khuzhin](https://github.com/azat))
+-   Implement `char` function similar to one in [mysql](https://dev.mysql.com/doc/refman/8.0/en/string-functions.html#function_char) [#7486](https://github.com/ClickHouse/ClickHouse/pull/7486) ([sundyli](https://github.com/sundy-li))
+-   Add `bitmapTransform` function. It transforms an array of values in a bitmap to another array of values, the result is a new bitmap [#7598](https://github.com/ClickHouse/ClickHouse/pull/7598) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Implemented `javaHashUTF16LE()` function [#7651](https://github.com/ClickHouse/ClickHouse/pull/7651) ([achimbab](https://github.com/achimbab))
+-   Add `_shard_num` virtual column for the Distributed engine [#7624](https://github.com/ClickHouse/ClickHouse/pull/7624) ([Azat Khuzhin](https://github.com/azat))
+
+#### Experimental Feature {#experimental-feature}
+
+-   Support for processors (new query execution pipeline) in `MergeTree`. [#7181](https://github.com/ClickHouse/ClickHouse/pull/7181) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+
+#### Bug Fix {#bug-fix-1}
+
+-   Fix incorrect float parsing in `Values` [#7817](https://github.com/ClickHouse/ClickHouse/issues/7817) [#7870](https://github.com/ClickHouse/ClickHouse/pull/7870) ([tavplubix](https://github.com/tavplubix))
+-   Fix rare deadlock which can happen when trace_log is enabled. [#7838](https://github.com/ClickHouse/ClickHouse/pull/7838) ([filimonov](https://github.com/filimonov))
+-   Prevent message duplication when producing Kafka table has any MVs selecting from it [#7265](https://github.com/ClickHouse/ClickHouse/pull/7265) ([Ivan](https://github.com/abyss7))
+-   Support for `Array(LowCardinality(Nullable(String)))` in `IN`. Resolves [#7364](https://github.com/ClickHouse/ClickHouse/issues/7364) [#7366](https://github.com/ClickHouse/ClickHouse/pull/7366) ([achimbab](https://github.com/achimbab))
+-   Add handling of `SQL_TINYINT` and `SQL_BIGINT`, and fix handling of `SQL_FLOAT` data source types in ODBC Bridge. [#7491](https://github.com/ClickHouse/ClickHouse/pull/7491) ([Denis Glazachev](https://github.com/traceon))
+-   Fix aggregation (`avg` and quantiles) over empty decimal columns [#7431](https://github.com/ClickHouse/ClickHouse/pull/7431) ([Andrey Konyaev](https://github.com/akonyaev90))
+-   Fix `INSERT` into Distributed with `MATERIALIZED` columns [#7377](https://github.com/ClickHouse/ClickHouse/pull/7377) ([Azat Khuzhin](https://github.com/azat))
+-   Make `MOVE PARTITION` work if some parts of partition are already on destination disk or volume [#7434](https://github.com/ClickHouse/ClickHouse/pull/7434) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Fixed bug with hardlinks failing to be created during mutations in `ReplicatedMergeTree` in multi-disk configurations. [#7558](https://github.com/ClickHouse/ClickHouse/pull/7558) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Fixed a bug with a mutation on a MergeTree when whole part remains unchanged and best space is being found on another disk [#7602](https://github.com/ClickHouse/ClickHouse/pull/7602) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Fixed bug with `keep_free_space_ratio` not being read from disks configuration [#7645](https://github.com/ClickHouse/ClickHouse/pull/7645) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Fix bug with table contains only `Tuple` columns or columns with complex paths. Fixes [7541](https://github.com/ClickHouse/ClickHouse/issues/7541). [#7545](https://github.com/ClickHouse/ClickHouse/pull/7545) ([alesapin](https://github.com/alesapin))
+-   Do not account memory for Buffer engine in max_memory_usage limit [#7552](https://github.com/ClickHouse/ClickHouse/pull/7552) ([Azat Khuzhin](https://github.com/azat))
+-   Fix final mark usage in `MergeTree` tables ordered by `tuple()`. In rare cases it could lead to `Can't adjust last granule` error while select. [#7639](https://github.com/ClickHouse/ClickHouse/pull/7639) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix bug in mutations that have predicate with actions that require context (for example functions for json), which may lead to crashes or strange exceptions. [#7664](https://github.com/ClickHouse/ClickHouse/pull/7664) ([alesapin](https://github.com/alesapin))
+-   Fix mismatch of database and table names escaping in `data/` and `shadow/` directories [#7575](https://github.com/ClickHouse/ClickHouse/pull/7575) ([Alexander Burmak](https://github.com/Alex-Burmak))
+-   Support duplicated keys in RIGHT\|FULL JOINs, e.g. `ON t.x = u.x AND t.x = u.y`. Fix crash in this case. [#7586](https://github.com/ClickHouse/ClickHouse/pull/7586) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix `Not found column <expression> in block` when joining on expression with RIGHT or FULL JOIN. [#7641](https://github.com/ClickHouse/ClickHouse/pull/7641) ([Artem Zuikov](https://github.com/4ertus2))
+-   One more attempt to fix infinite loop in `PrettySpace` format [#7591](https://github.com/ClickHouse/ClickHouse/pull/7591) ([Olga Khvostikova](https://github.com/stavrolia))
+-   Fix bug in `concat` function when all arguments were `FixedString` of the same size. [#7635](https://github.com/ClickHouse/ClickHouse/pull/7635) ([alesapin](https://github.com/alesapin))
+-   Fixed exception in case of using 1 argument while defining S3, URL and HDFS storages. [#7618](https://github.com/ClickHouse/ClickHouse/pull/7618) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Fix scope of the InterpreterSelectQuery for views with query [#7601](https://github.com/ClickHouse/ClickHouse/pull/7601) ([Azat Khuzhin](https://github.com/azat))
+
+#### Improvement {#improvement}
+
+-   `Nullable` columns recognized and NULL-values handled correctly by ODBC-bridge [#7402](https://github.com/ClickHouse/ClickHouse/pull/7402) ([Vasily Nemkov](https://github.com/Enmk))
+-   Write current batch for distributed send atomically [#7600](https://github.com/ClickHouse/ClickHouse/pull/7600) ([Azat Khuzhin](https://github.com/azat))
+-   Throw an exception if we cannot detect table for column name in query. [#7358](https://github.com/ClickHouse/ClickHouse/pull/7358) ([Artem Zuikov](https://github.com/4ertus2))
+-   Add `merge_max_block_size` setting to `MergeTreeSettings` [#7412](https://github.com/ClickHouse/ClickHouse/pull/7412) ([Artem Zuikov](https://github.com/4ertus2))
+-   Queries with `HAVING` and without `GROUP BY` assume group by constant. So, `SELECT 1 HAVING 1` now returns a result. [#7496](https://github.com/ClickHouse/ClickHouse/pull/7496) ([Amos Bird](https://github.com/amosbird))
+-   Support parsing `(X,)` as tuple similar to python. [#7501](https://github.com/ClickHouse/ClickHouse/pull/7501), [#7562](https://github.com/ClickHouse/ClickHouse/pull/7562) ([Amos Bird](https://github.com/amosbird))
+-   Make `range` function behaviors almost like pythonic one. [#7518](https://github.com/ClickHouse/ClickHouse/pull/7518) ([sundyli](https://github.com/sundy-li))
+-   Add `constraints` columns to table `system.settings` [#7553](https://github.com/ClickHouse/ClickHouse/pull/7553) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Better Null format for tcp handler, so that it’s possible to use `select ignore(<expression>) from table format Null` for perf measure via clickhouse-client [#7606](https://github.com/ClickHouse/ClickHouse/pull/7606) ([Amos Bird](https://github.com/amosbird))
+-   Queries like `CREATE TABLE ... AS (SELECT (1, 2))` are parsed correctly [#7542](https://github.com/ClickHouse/ClickHouse/pull/7542) ([hcz](https://github.com/hczhcz))
+
+#### Performance Improvement {#performance-improvement}
+
+-   The performance of aggregation over short string keys is improved. [#6243](https://github.com/ClickHouse/ClickHouse/pull/6243) ([Alexander Kuzmenkov](https://github.com/akuzm), [Amos Bird](https://github.com/amosbird))
+-   Run another pass of syntax/expression analysis to get potential optimizations after constant predicates are folded. [#7497](https://github.com/ClickHouse/ClickHouse/pull/7497) ([Amos Bird](https://github.com/amosbird))
+-   Use storage meta info to evaluate trivial `SELECT count() FROM table;` [#7510](https://github.com/ClickHouse/ClickHouse/pull/7510) ([Amos Bird](https://github.com/amosbird), [alexey-milovidov](https://github.com/alexey-milovidov))
+-   Vectorize processing `arrayReduce` similar to Aggregator `addBatch`. [#7608](https://github.com/ClickHouse/ClickHouse/pull/7608) ([Amos Bird](https://github.com/amosbird))
+-   Minor improvements in performance of `Kafka` consumption [#7475](https://github.com/ClickHouse/ClickHouse/pull/7475) ([Ivan](https://github.com/abyss7))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement}
+
+-   Add support for cross-compiling to the CPU architecture AARCH64. Refactor packager script. [#7370](https://github.com/ClickHouse/ClickHouse/pull/7370) [#7539](https://github.com/ClickHouse/ClickHouse/pull/7539) ([Ivan](https://github.com/abyss7))
+-   Unpack darwin-x86_64 and linux-aarch64 toolchains into mounted Docker volume when building packages [#7534](https://github.com/ClickHouse/ClickHouse/pull/7534) ([Ivan](https://github.com/abyss7))
+-   Update Docker Image for Binary Packager [#7474](https://github.com/ClickHouse/ClickHouse/pull/7474) ([Ivan](https://github.com/abyss7))
+-   Fixed compile errors on MacOS Catalina [#7585](https://github.com/ClickHouse/ClickHouse/pull/7585) ([Ernest Poletaev](https://github.com/ernestp))
+-   Some refactoring in query analysis logic: split complex class into several simple ones. [#7454](https://github.com/ClickHouse/ClickHouse/pull/7454) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix build without submodules [#7295](https://github.com/ClickHouse/ClickHouse/pull/7295) ([proller](https://github.com/proller))
+-   Better `add_globs` in CMake files [#7418](https://github.com/ClickHouse/ClickHouse/pull/7418) ([Amos Bird](https://github.com/amosbird))
+-   Remove hardcoded paths in `unwind` target [#7460](https://github.com/ClickHouse/ClickHouse/pull/7460) ([Konstantin Podshumok](https://github.com/podshumok))
+-   Allow to use mysql format without ssl [#7524](https://github.com/ClickHouse/ClickHouse/pull/7524) ([proller](https://github.com/proller))
+
+#### Other {#other}
+
+-   Added ANTLR4 grammar for ClickHouse SQL dialect [#7595](https://github.com/ClickHouse/ClickHouse/issues/7595) [#7596](https://github.com/ClickHouse/ClickHouse/pull/7596) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+## ClickHouse Release 19.16 {#clickhouse-release-v19-16}
+
+#### ClickHouse Release 19.16.14.65, 2020-03-25 {#clickhouse-release-v19-16-14-65-2020-03-25}
+
+-   Fixed up a bug in batched calculations of ternary logical OPs on multiple arguments (more than 10). [#8718](https://github.com/ClickHouse/ClickHouse/pull/8718) ([Alexander Kazakov](https://github.com/Akazz)) This bugfix was backported to version 19.16 by a special request from Altinity.
+
+#### ClickHouse Release 19.16.14.65, 2020-03-05 {#clickhouse-release-v19-16-14-65-2020-03-05}
+
+-   Fix distributed subqueries incompatibility with older CH versions. Fixes [#7851](https://github.com/ClickHouse/ClickHouse/issues/7851)
+    [(tabplubix)](https://github.com/tavplubix)
+-   When executing `CREATE` query, fold constant expressions in storage engine arguments. Replace empty database name with current database. Fixes [#6508](https://github.com/ClickHouse/ClickHouse/issues/6508), [#3492](https://github.com/ClickHouse/ClickHouse/issues/3492). Also fix check for local address in `ClickHouseDictionarySource`.
+    [#9262](https://github.com/ClickHouse/ClickHouse/pull/9262) [(tabplubix)](https://github.com/tavplubix)
+-   Now background merges in `*MergeTree` table engines family preserve storage policy volume order more accurately.
+    [#8549](https://github.com/ClickHouse/ClickHouse/pull/8549) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Prevent losing data in `Kafka` in rare cases when exception happens after reading suffix but before commit. Fixes [#9378](https://github.com/ClickHouse/ClickHouse/issues/9378). Related: [#7175](https://github.com/ClickHouse/ClickHouse/issues/7175)
+    [#9507](https://github.com/ClickHouse/ClickHouse/pull/9507) [(filimonov)](https://github.com/filimonov)
+-   Fix bug leading to server termination when trying to use / drop `Kafka` table created with wrong parameters. Fixes [#9494](https://github.com/ClickHouse/ClickHouse/issues/9494). Incorporates [#9507](https://github.com/ClickHouse/ClickHouse/issues/9507).
+    [#9513](https://github.com/ClickHouse/ClickHouse/pull/9513) [(filimonov)](https://github.com/filimonov)
+-   Allow using `MaterializedView` with subqueries above `Kafka` tables.
+    [#8197](https://github.com/ClickHouse/ClickHouse/pull/8197) ([filimonov](https://github.com/filimonov))
+
+#### New Feature {#new-feature-1}
+
+-   Add `deduplicate_blocks_in_dependent_materialized_views` option to control the behaviour of idempotent inserts into tables with materialized views. This new feature was added to the bugfix release by a special request from Altinity.
+    [#9070](https://github.com/ClickHouse/ClickHouse/pull/9070) [(urykhy)](https://github.com/urykhy)
+
+### ClickHouse Release 19.16.2.2, 2019-10-30 {#clickhouse-release-v19-16-2-2-2019-10-30}
+
+#### Backward Incompatible Change {#backward-incompatible-change-1}
+
+-   Add missing arity validation for count/counIf.
+    [#7095](https://github.com/ClickHouse/ClickHouse/issues/7095)
+    [#7298](https://github.com/ClickHouse/ClickHouse/pull/7298) ([Vdimir](https://github.com/Vdimir))
+-   Remove legacy `asterisk_left_columns_only` setting (it was disabled by default).
+    [#7335](https://github.com/ClickHouse/ClickHouse/pull/7335) ([Artem
+    Zuikov](https://github.com/4ertus2))
+-   Format strings for Template data format are now specified in files.
+    [#7118](https://github.com/ClickHouse/ClickHouse/pull/7118)
+    ([tavplubix](https://github.com/tavplubix))
+
+#### New Feature {#new-feature-2}
+
+-   Introduce uniqCombined64() to calculate cardinality greater than UINT_MAX.
+    [#7213](https://github.com/ClickHouse/ClickHouse/pull/7213),
+    [#7222](https://github.com/ClickHouse/ClickHouse/pull/7222) ([Azat
+    Khuzhin](https://github.com/azat))
+-   Support Bloom filter indexes on Array columns.
+    [#6984](https://github.com/ClickHouse/ClickHouse/pull/6984)
+    ([achimbab](https://github.com/achimbab))
+-   Add a function `getMacro(name)` that returns String with the value of corresponding `<macros>`
+    from server configuration. [#7240](https://github.com/ClickHouse/ClickHouse/pull/7240)
+    ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Set two configuration options for a dictionary based on an HTTP source: `credentials` and
+    `http-headers`. [#7092](https://github.com/ClickHouse/ClickHouse/pull/7092) ([Guillaume
+    Tassery](https://github.com/YiuRULE))
+-   Add a new ProfileEvent `Merge` that counts the number of launched background merges.
+    [#7093](https://github.com/ClickHouse/ClickHouse/pull/7093) ([Mikhail
+    Korotov](https://github.com/millb))
+-   Add fullHostName function that returns a fully qualified domain name.
+    [#7263](https://github.com/ClickHouse/ClickHouse/issues/7263)
+    [#7291](https://github.com/ClickHouse/ClickHouse/pull/7291) ([sundyli](https://github.com/sundy-li))
+-   Add function `arraySplit` and `arrayReverseSplit` which split an array by “cut off”
+    conditions. They are useful in time sequence handling.
+    [#7294](https://github.com/ClickHouse/ClickHouse/pull/7294) ([hcz](https://github.com/hczhcz))
+-   Add new functions that return the Array of all matched indices in multiMatch family of functions.
+    [#7299](https://github.com/ClickHouse/ClickHouse/pull/7299) ([Danila
+    Kutenin](https://github.com/danlark1))
+-   Add a new database engine `Lazy` that is optimized for storing a large number of small -Log
+    tables. [#7171](https://github.com/ClickHouse/ClickHouse/pull/7171) ([Nikita
+    Vasilev](https://github.com/nikvas0))
+-   Add aggregate functions groupBitmapAnd, -Or, -Xor for bitmap columns. [#7109](https://github.com/ClickHouse/ClickHouse/pull/7109) ([Zhichang
+    Yu](https://github.com/yuzhichang))
+-   Add aggregate function combinators -OrNull and -OrDefault, which return null
+    or default values when there is nothing to aggregate.
+    [#7331](https://github.com/ClickHouse/ClickHouse/pull/7331)
+    ([hcz](https://github.com/hczhcz))
+-   Introduce CustomSeparated data format that supports custom escaping and
+    delimiter rules. [#7118](https://github.com/ClickHouse/ClickHouse/pull/7118)
+    ([tavplubix](https://github.com/tavplubix))
+-   Support Redis as source of external dictionary. [#4361](https://github.com/ClickHouse/ClickHouse/pull/4361) [#6962](https://github.com/ClickHouse/ClickHouse/pull/6962) ([comunodi](https://github.com/comunodi), [Anton
+    Popov](https://github.com/CurtizJ))
+
+#### Bug Fix {#bug-fix-2}
+
+-   Fix wrong query result if it has `WHERE IN (SELECT ...)` section and `optimize_read_in_order` is
+    used. [#7371](https://github.com/ClickHouse/ClickHouse/pull/7371) ([Anton
+    Popov](https://github.com/CurtizJ))
+-   Disabled MariaDB authentication plugin, which depends on files outside of project.
+    [#7140](https://github.com/ClickHouse/ClickHouse/pull/7140) ([Yuriy
+    Baranov](https://github.com/yurriy))
+-   Fix exception `Cannot convert column ... because it is constant but values of constants are different in source and result` which could rarely happen when functions `now()`, `today()`,
+    `yesterday()`, `randConstant()` are used.
+    [#7156](https://github.com/ClickHouse/ClickHouse/pull/7156) ([Nikolai
+    Kochetov](https://github.com/KochetovNicolai))
+-   Fixed issue of using HTTP keep alive timeout instead of TCP keep alive timeout.
+    [#7351](https://github.com/ClickHouse/ClickHouse/pull/7351) ([Vasily
+    Nemkov](https://github.com/Enmk))
+-   Fixed a segmentation fault in groupBitmapOr (issue [#7109](https://github.com/ClickHouse/ClickHouse/issues/7109)).
+    [#7289](https://github.com/ClickHouse/ClickHouse/pull/7289) ([Zhichang
+    Yu](https://github.com/yuzhichang))
+-   For materialized views the commit for Kafka is called after all data were written.
+    [#7175](https://github.com/ClickHouse/ClickHouse/pull/7175) ([Ivan](https://github.com/abyss7))
+-   Fixed wrong `duration_ms` value in `system.part_log` table. It was ten times off.
+    [#7172](https://github.com/ClickHouse/ClickHouse/pull/7172) ([Vladimir
+    Chebotarev](https://github.com/excitoon))
+-   A quick fix to resolve crash in LIVE VIEW table and re-enabling all LIVE VIEW tests.
+    [#7201](https://github.com/ClickHouse/ClickHouse/pull/7201)
+    ([vzakaznikov](https://github.com/vzakaznikov))
+-   Serialize NULL values correctly in min/max indexes of MergeTree parts.
+    [#7234](https://github.com/ClickHouse/ClickHouse/pull/7234) ([Alexander
+    Kuzmenkov](https://github.com/akuzm))
+-   Don’t put virtual columns to .sql metadata when table is created as `CREATE TABLE AS`.
+    [#7183](https://github.com/ClickHouse/ClickHouse/pull/7183) ([Ivan](https://github.com/abyss7))
+-   Fix segmentation fault in `ATTACH PART` query.
+    [#7185](https://github.com/ClickHouse/ClickHouse/pull/7185)
+    ([alesapin](https://github.com/alesapin))
+-   Fix wrong result for some queries given by the optimization of empty IN subqueries and empty
+    INNER/RIGHT JOIN. [#7284](https://github.com/ClickHouse/ClickHouse/pull/7284) ([Nikolai
+    Kochetov](https://github.com/KochetovNicolai))
+-   Fixing AddressSanitizer error in the LIVE VIEW getHeader() method.
+    [#7271](https://github.com/ClickHouse/ClickHouse/pull/7271)
+    ([vzakaznikov](https://github.com/vzakaznikov))
+
+#### Improvement {#improvement-1}
+
+-   Add a message in case of queue_wait_max_ms wait takes place.
+    [#7390](https://github.com/ClickHouse/ClickHouse/pull/7390) ([Azat
+    Khuzhin](https://github.com/azat))
+-   Made setting `s3_min_upload_part_size` table-level.
+    [#7059](https://github.com/ClickHouse/ClickHouse/pull/7059) ([Vladimir
+    Chebotarev](https://github.com/excitoon))
+-   Check TTL in StorageFactory. [#7304](https://github.com/ClickHouse/ClickHouse/pull/7304)
+    ([sundyli](https://github.com/sundy-li))
+-   Squash left-hand blocks in partial merge join (optimization).
+    [#7122](https://github.com/ClickHouse/ClickHouse/pull/7122) ([Artem
+    Zuikov](https://github.com/4ertus2))
+-   Do not allow non-deterministic functions in mutations of Replicated table engines, because this
+    can introduce inconsistencies between replicas.
+    [#7247](https://github.com/ClickHouse/ClickHouse/pull/7247) ([Alexander
+    Kazakov](https://github.com/Akazz))
+-   Disable memory tracker while converting exception stack trace to string. It can prevent the loss
+    of error messages of type `Memory limit exceeded` on server, which caused the `Attempt to read after eof` exception on client. [#7264](https://github.com/ClickHouse/ClickHouse/pull/7264)
+    ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Miscellaneous format improvements. Resolves
+    [#6033](https://github.com/ClickHouse/ClickHouse/issues/6033),
+    [#2633](https://github.com/ClickHouse/ClickHouse/issues/2633),
+    [#6611](https://github.com/ClickHouse/ClickHouse/issues/6611),
+    [#6742](https://github.com/ClickHouse/ClickHouse/issues/6742)
+    [#7215](https://github.com/ClickHouse/ClickHouse/pull/7215)
+    ([tavplubix](https://github.com/tavplubix))
+-   ClickHouse ignores values on the right side of IN operator that are not convertible to the left
+    side type. Make it work properly for compound types – Array and Tuple.
+    [#7283](https://github.com/ClickHouse/ClickHouse/pull/7283) ([Alexander
+    Kuzmenkov](https://github.com/akuzm))
+-   Support missing inequalities for ASOF JOIN. It’s possible to join less-or-equal variant and strict
+    greater and less variants for ASOF column in ON syntax.
+    [#7282](https://github.com/ClickHouse/ClickHouse/pull/7282) ([Artem
+    Zuikov](https://github.com/4ertus2))
+-   Optimize partial merge join. [#7070](https://github.com/ClickHouse/ClickHouse/pull/7070)
+    ([Artem Zuikov](https://github.com/4ertus2))
+-   Do not use more than 98K of memory in uniqCombined functions.
+    [#7236](https://github.com/ClickHouse/ClickHouse/pull/7236),
+    [#7270](https://github.com/ClickHouse/ClickHouse/pull/7270) ([Azat
+    Khuzhin](https://github.com/azat))
+-   Flush parts of right-hand joining table on disk in PartialMergeJoin (if there is not enough
+    memory). Load data back when needed. [#7186](https://github.com/ClickHouse/ClickHouse/pull/7186)
+    ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Performance Improvement {#performance-improvement-1}
+
+-   Speed up joinGet with const arguments by avoiding data duplication.
+    [#7359](https://github.com/ClickHouse/ClickHouse/pull/7359) ([Amos
+    Bird](https://github.com/amosbird))
+-   Return early if the subquery is empty.
+    [#7007](https://github.com/ClickHouse/ClickHouse/pull/7007) ([小路](https://github.com/nicelulu))
+-   Optimize parsing of SQL expression in Values.
+    [#6781](https://github.com/ClickHouse/ClickHouse/pull/6781)
+    ([tavplubix](https://github.com/tavplubix))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-1}
+
+-   Disable some contribs for cross-compilation to Mac OS.
+    [#7101](https://github.com/ClickHouse/ClickHouse/pull/7101) ([Ivan](https://github.com/abyss7))
+-   Add missing linking with PocoXML for clickhouse_common_io.
+    [#7200](https://github.com/ClickHouse/ClickHouse/pull/7200) ([Azat
+    Khuzhin](https://github.com/azat))
+-   Accept multiple test filter arguments in clickhouse-test.
+    [#7226](https://github.com/ClickHouse/ClickHouse/pull/7226) ([Alexander
+    Kuzmenkov](https://github.com/akuzm))
+-   Enable musl and jemalloc for ARM. [#7300](https://github.com/ClickHouse/ClickHouse/pull/7300)
+    ([Amos Bird](https://github.com/amosbird))
+-   Added `--client-option` parameter to `clickhouse-test` to pass additional parameters to client.
+    [#7277](https://github.com/ClickHouse/ClickHouse/pull/7277) ([Nikolai
+    Kochetov](https://github.com/KochetovNicolai))
+-   Preserve existing configs on rpm package upgrade.
+    [#7103](https://github.com/ClickHouse/ClickHouse/pull/7103)
+    ([filimonov](https://github.com/filimonov))
+-   Fix errors detected by PVS. [#7153](https://github.com/ClickHouse/ClickHouse/pull/7153) ([Artem
+    Zuikov](https://github.com/4ertus2))
+-   Fix build for Darwin. [#7149](https://github.com/ClickHouse/ClickHouse/pull/7149)
+    ([Ivan](https://github.com/abyss7))
+-   glibc 2.29 compatibility. [#7142](https://github.com/ClickHouse/ClickHouse/pull/7142) ([Amos
+    Bird](https://github.com/amosbird))
+-   Make sure dh_clean does not touch potential source files.
+    [#7205](https://github.com/ClickHouse/ClickHouse/pull/7205) ([Amos
+    Bird](https://github.com/amosbird))
+-   Attempt to avoid conflict when updating from altinity rpm - it has config file packaged separately
+    in clickhouse-server-common. [#7073](https://github.com/ClickHouse/ClickHouse/pull/7073)
+    ([filimonov](https://github.com/filimonov))
+-   Optimize some header files for faster rebuilds.
+    [#7212](https://github.com/ClickHouse/ClickHouse/pull/7212),
+    [#7231](https://github.com/ClickHouse/ClickHouse/pull/7231) ([Alexander
+    Kuzmenkov](https://github.com/akuzm))
+-   Add performance tests for Date and DateTime. [#7332](https://github.com/ClickHouse/ClickHouse/pull/7332) ([Vasily
+    Nemkov](https://github.com/Enmk))
+-   Fix some tests that contained non-deterministic mutations.
+    [#7132](https://github.com/ClickHouse/ClickHouse/pull/7132) ([Alexander
+    Kazakov](https://github.com/Akazz))
+-   Add build with MemorySanitizer to CI. [#7066](https://github.com/ClickHouse/ClickHouse/pull/7066)
+    ([Alexander Kuzmenkov](https://github.com/akuzm))
+-   Avoid use of uninitialized values in MetricsTransmitter.
+    [#7158](https://github.com/ClickHouse/ClickHouse/pull/7158) ([Azat
+    Khuzhin](https://github.com/azat))
+-   Fix some issues in Fields found by MemorySanitizer.
+    [#7135](https://github.com/ClickHouse/ClickHouse/pull/7135),
+    [#7179](https://github.com/ClickHouse/ClickHouse/pull/7179) ([Alexander
+    Kuzmenkov](https://github.com/akuzm)), [#7376](https://github.com/ClickHouse/ClickHouse/pull/7376)
+    ([Amos Bird](https://github.com/amosbird))
+-   Fix undefined behavior in murmurhash32. [#7388](https://github.com/ClickHouse/ClickHouse/pull/7388) ([Amos
+    Bird](https://github.com/amosbird))
+-   Fix undefined behavior in StoragesInfoStream. [#7384](https://github.com/ClickHouse/ClickHouse/pull/7384)
+    ([tavplubix](https://github.com/tavplubix))
+-   Fixed constant expressions folding for external database engines (MySQL, ODBC, JDBC). In previous
+    versions it wasn’t working for multiple constant expressions and was not working at all for Date,
+    DateTime and UUID. This fixes [#7245](https://github.com/ClickHouse/ClickHouse/issues/7245)
+    [#7252](https://github.com/ClickHouse/ClickHouse/pull/7252)
+    ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixing ThreadSanitizer data race error in the LIVE VIEW when accessing no_users_thread variable.
+    [#7353](https://github.com/ClickHouse/ClickHouse/pull/7353)
+    ([vzakaznikov](https://github.com/vzakaznikov))
+-   Get rid of malloc symbols in libcommon
+    [#7134](https://github.com/ClickHouse/ClickHouse/pull/7134),
+    [#7065](https://github.com/ClickHouse/ClickHouse/pull/7065) ([Amos
+    Bird](https://github.com/amosbird))
+-   Add global flag ENABLE_LIBRARIES for disabling all libraries.
+    [#7063](https://github.com/ClickHouse/ClickHouse/pull/7063)
+    ([proller](https://github.com/proller))
+
+#### Code Cleanup {#code-cleanup}
+
+-   Generalize configuration repository to prepare for DDL for Dictionaries. [#7155](https://github.com/ClickHouse/ClickHouse/pull/7155)
+    ([alesapin](https://github.com/alesapin))
+-   Parser for dictionaries DDL without any semantic.
+    [#7209](https://github.com/ClickHouse/ClickHouse/pull/7209)
+    ([alesapin](https://github.com/alesapin))
+-   Split ParserCreateQuery into different smaller parsers.
+    [#7253](https://github.com/ClickHouse/ClickHouse/pull/7253)
+    ([alesapin](https://github.com/alesapin))
+-   Small refactoring and renaming near external dictionaries.
+    [#7111](https://github.com/ClickHouse/ClickHouse/pull/7111)
+    ([alesapin](https://github.com/alesapin))
+-   Refactor some code to prepare for role-based access control. [#7235](https://github.com/ClickHouse/ClickHouse/pull/7235) ([Vitaly
+    Baranov](https://github.com/vitlibar))
+-   Some improvements in DatabaseOrdinary code.
+    [#7086](https://github.com/ClickHouse/ClickHouse/pull/7086) ([Nikita
+    Vasilev](https://github.com/nikvas0))
+-   Do not use iterators in find() and emplace() methods of hash tables.
+    [#7026](https://github.com/ClickHouse/ClickHouse/pull/7026) ([Alexander
+    Kuzmenkov](https://github.com/akuzm))
+-   Fix getMultipleValuesFromConfig in case when parameter root is not empty. [#7374](https://github.com/ClickHouse/ClickHouse/pull/7374)
+    ([Mikhail Korotov](https://github.com/millb))
+-   Remove some copy-paste (TemporaryFile and TemporaryFileStream)
+    [#7166](https://github.com/ClickHouse/ClickHouse/pull/7166) ([Artem
+    Zuikov](https://github.com/4ertus2))
+-   Improved code readability a little bit (`MergeTreeData::getActiveContainingPart`).
+    [#7361](https://github.com/ClickHouse/ClickHouse/pull/7361) ([Vladimir
+    Chebotarev](https://github.com/excitoon))
+-   Wait for all scheduled jobs, which are using local objects, if `ThreadPool::schedule(...)` throws
+    an exception. Rename `ThreadPool::schedule(...)` to `ThreadPool::scheduleOrThrowOnError(...)` and
+    fix comments to make obvious that it may throw.
+    [#7350](https://github.com/ClickHouse/ClickHouse/pull/7350)
+    ([tavplubix](https://github.com/tavplubix))
+
+## ClickHouse Release 19.15 {#clickhouse-release-19-15}
+
+### ClickHouse Release 19.15.4.10, 2019-10-31 {#clickhouse-release-19-15-4-10-2019-10-31}
+
+#### Bug Fix {#bug-fix-3}
+
+-   Added handling of SQL_TINYINT and SQL_BIGINT, and fix handling of SQL_FLOAT data source types in ODBC Bridge.
+    [#7491](https://github.com/ClickHouse/ClickHouse/pull/7491) ([Denis Glazachev](https://github.com/traceon))
+-   Allowed to have some parts on destination disk or volume in MOVE PARTITION.
+    [#7434](https://github.com/ClickHouse/ClickHouse/pull/7434) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Fixed NULL-values in nullable columns through ODBC-bridge.
+    [#7402](https://github.com/ClickHouse/ClickHouse/pull/7402) ([Vasily Nemkov](https://github.com/Enmk))
+-   Fixed INSERT into Distributed non local node with MATERIALIZED columns.
+    [#7377](https://github.com/ClickHouse/ClickHouse/pull/7377) ([Azat Khuzhin](https://github.com/azat))
+-   Fixed function getMultipleValuesFromConfig.
+    [#7374](https://github.com/ClickHouse/ClickHouse/pull/7374) ([Mikhail Korotov](https://github.com/millb))
+-   Fixed issue of using HTTP keep alive timeout instead of TCP keep alive timeout.
+    [#7351](https://github.com/ClickHouse/ClickHouse/pull/7351) ([Vasily Nemkov](https://github.com/Enmk))
+-   Wait for all jobs to finish on exception (fixes rare segfaults).
+    [#7350](https://github.com/ClickHouse/ClickHouse/pull/7350) ([tavplubix](https://github.com/tavplubix))
+-   Don’t push to MVs when inserting into Kafka table.
+    [#7265](https://github.com/ClickHouse/ClickHouse/pull/7265) ([Ivan](https://github.com/abyss7))
+-   Disable memory tracker for exception stack.
+    [#7264](https://github.com/ClickHouse/ClickHouse/pull/7264) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fixed bad code in transforming query for external database.
+    [#7252](https://github.com/ClickHouse/ClickHouse/pull/7252) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Avoid use of uninitialized values in MetricsTransmitter.
+    [#7158](https://github.com/ClickHouse/ClickHouse/pull/7158) ([Azat Khuzhin](https://github.com/azat))
+-   Added example config with macros for tests ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.15.3.6, 2019-10-09 {#clickhouse-release-19-15-3-6-2019-10-09}
+
+#### Bug Fix {#bug-fix-4}
+
+-   Fixed bad_variant in hashed dictionary.
+    ([alesapin](https://github.com/alesapin))
+-   Fixed up bug with segmentation fault in ATTACH PART query.
+    ([alesapin](https://github.com/alesapin))
+-   Fixed time calculation in `MergeTreeData`.
+    ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Commit to Kafka explicitly after the writing is finalized.
+    [#7175](https://github.com/ClickHouse/ClickHouse/pull/7175) ([Ivan](https://github.com/abyss7))
+-   Serialize NULL values correctly in min/max indexes of MergeTree parts.
+    [#7234](https://github.com/ClickHouse/ClickHouse/pull/7234) ([Alexander Kuzmenkov](https://github.com/akuzm))
+
+### ClickHouse Release 19.15.2.2, 2019-10-01 {#clickhouse-release-19-15-2-2-2019-10-01}
+
+#### New Feature {#new-feature-3}
+
+-   Tiered storage: support to use multiple storage volumes for tables with MergeTree engine. It’s possible to store fresh data on SSD and automatically move old data to HDD. ([example](https://clickhouse.github.io/clickhouse-presentations/meetup30/new_features/#12)). [#4918](https://github.com/ClickHouse/ClickHouse/pull/4918) ([Igr](https://github.com/ObjatieGroba)) [#6489](https://github.com/ClickHouse/ClickHouse/pull/6489) ([alesapin](https://github.com/alesapin))
+-   Add table function `input` for reading incoming data in `INSERT SELECT` query. [#5450](https://github.com/ClickHouse/ClickHouse/pull/5450) ([palasonic1](https://github.com/palasonic1)) [#6832](https://github.com/ClickHouse/ClickHouse/pull/6832) ([Anton Popov](https://github.com/CurtizJ))
+-   Add a `sparse_hashed` dictionary layout, that is functionally equivalent to the `hashed` layout, but is more memory efficient. It uses about twice as less memory at the cost of slower value retrieval. [#6894](https://github.com/ClickHouse/ClickHouse/pull/6894) ([Azat Khuzhin](https://github.com/azat))
+-   Implement ability to define list of users for access to dictionaries. Only current connected database using. [#6907](https://github.com/ClickHouse/ClickHouse/pull/6907) ([Guillaume Tassery](https://github.com/YiuRULE))
+-   Add `LIMIT` option to `SHOW` query. [#6944](https://github.com/ClickHouse/ClickHouse/pull/6944) ([Philipp Malkovsky](https://github.com/malkfilipp))
+-   Add `bitmapSubsetLimit(bitmap, range_start, limit)` function, that returns subset of the smallest `limit` values in set that is no smaller than `range_start`. [#6957](https://github.com/ClickHouse/ClickHouse/pull/6957) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Add `bitmapMin` and `bitmapMax` functions. [#6970](https://github.com/ClickHouse/ClickHouse/pull/6970) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Add function `repeat` related to [issue-6648](https://github.com/ClickHouse/ClickHouse/issues/6648) [#6999](https://github.com/ClickHouse/ClickHouse/pull/6999) ([flynn](https://github.com/ucasFL))
+
+#### Experimental Feature {#experimental-feature-1}
+
+-   Implement (in memory) Merge Join variant that does not change current pipeline. Result is partially sorted by merge key. Set `partial_merge_join = 1` to use this feature. The Merge Join is still in development. [#6940](https://github.com/ClickHouse/ClickHouse/pull/6940) ([Artem Zuikov](https://github.com/4ertus2))
+-   Add `S3` engine and table function. It is still in development (no authentication support yet). [#5596](https://github.com/ClickHouse/ClickHouse/pull/5596) ([Vladimir Chebotarev](https://github.com/excitoon))
+
+#### Improvement {#improvement-2}
+
+-   Every message read from Kafka is inserted atomically. This resolves almost all known issues with Kafka engine. [#6950](https://github.com/ClickHouse/ClickHouse/pull/6950) ([Ivan](https://github.com/abyss7))
+-   Improvements for failover of Distributed queries. Shorten recovery time, also it is now configurable and can be seen in `system.clusters`. [#6399](https://github.com/ClickHouse/ClickHouse/pull/6399) ([Vasily Nemkov](https://github.com/Enmk))
+-   Support numeric values for Enums directly in `IN` section. #6766 [#6941](https://github.com/ClickHouse/ClickHouse/pull/6941) ([dimarub2000](https://github.com/dimarub2000))
+-   Support (optional, disabled by default) redirects on URL storage. [#6914](https://github.com/ClickHouse/ClickHouse/pull/6914) ([maqroll](https://github.com/maqroll))
+-   Add information message when client with an older version connects to a server. [#6893](https://github.com/ClickHouse/ClickHouse/pull/6893) ([Philipp Malkovsky](https://github.com/malkfilipp))
+-   Remove maximum backoff sleep time limit for sending data in Distributed tables [#6895](https://github.com/ClickHouse/ClickHouse/pull/6895) ([Azat Khuzhin](https://github.com/azat))
+-   Add ability to send profile events (counters) with cumulative values to graphite. It can be enabled under `<events_cumulative>` in server `config.xml`. [#6969](https://github.com/ClickHouse/ClickHouse/pull/6969) ([Azat Khuzhin](https://github.com/azat))
+-   Add automatically cast type `T` to `LowCardinality(T)` while inserting data in column of type `LowCardinality(T)` in Native format via HTTP. [#6891](https://github.com/ClickHouse/ClickHouse/pull/6891) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Add ability to use function `hex` without using `reinterpretAsString` for `Float32`, `Float64`. [#7024](https://github.com/ClickHouse/ClickHouse/pull/7024) ([Mikhail Korotov](https://github.com/millb))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-2}
+
+-   Add gdb-index to clickhouse binary with debug info. It will speed up startup time of `gdb`. [#6947](https://github.com/ClickHouse/ClickHouse/pull/6947) ([alesapin](https://github.com/alesapin))
+-   Speed up deb packaging with patched dpkg-deb which uses `pigz`. [#6960](https://github.com/ClickHouse/ClickHouse/pull/6960) ([alesapin](https://github.com/alesapin))
+-   Set `enable_fuzzing = 1` to enable libfuzzer instrumentation of all the project code. [#7042](https://github.com/ClickHouse/ClickHouse/pull/7042) ([kyprizel](https://github.com/kyprizel))
+-   Add split build smoke test in CI. [#7061](https://github.com/ClickHouse/ClickHouse/pull/7061) ([alesapin](https://github.com/alesapin))
+-   Add build with MemorySanitizer to CI. [#7066](https://github.com/ClickHouse/ClickHouse/pull/7066) ([Alexander Kuzmenkov](https://github.com/akuzm))
+-   Replace `libsparsehash` with `sparsehash-c11` [#6965](https://github.com/ClickHouse/ClickHouse/pull/6965) ([Azat Khuzhin](https://github.com/azat))
+
+#### Bug Fix {#bug-fix-5}
+
+-   Fixed performance degradation of index analysis on complex keys on large tables. This fixes #6924. [#7075](https://github.com/ClickHouse/ClickHouse/pull/7075) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix logical error causing segfaults when selecting from Kafka empty topic. [#6909](https://github.com/ClickHouse/ClickHouse/pull/6909) ([Ivan](https://github.com/abyss7))
+-   Fix too early MySQL connection close in `MySQLBlockInputStream.cpp`. [#6882](https://github.com/ClickHouse/ClickHouse/pull/6882) ([Clément Rodriguez](https://github.com/clemrodriguez))
+-   Returned support for very old Linux kernels (fix [#6841](https://github.com/ClickHouse/ClickHouse/issues/6841)) [#6853](https://github.com/ClickHouse/ClickHouse/pull/6853) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix possible data loss in `insert select` query in case of empty block in input stream. #6834 #6862 [#6911](https://github.com/ClickHouse/ClickHouse/pull/6911) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix for function `АrrayEnumerateUniqRanked` with empty arrays in params [#6928](https://github.com/ClickHouse/ClickHouse/pull/6928) ([proller](https://github.com/proller))
+-   Fix complex queries with array joins and global subqueries. [#6934](https://github.com/ClickHouse/ClickHouse/pull/6934) ([Ivan](https://github.com/abyss7))
+-   Fix `Unknown identifier` error in ORDER BY and GROUP BY with multiple JOINs [#7022](https://github.com/ClickHouse/ClickHouse/pull/7022) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed `MSan` warning while executing function with `LowCardinality` argument. [#7062](https://github.com/ClickHouse/ClickHouse/pull/7062) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+
+#### Backward Incompatible Change {#backward-incompatible-change-2}
+
+-   Changed serialization format of bitmap\* aggregate function states to improve performance. Serialized states of bitmap\* from previous versions cannot be read. [#6908](https://github.com/ClickHouse/ClickHouse/pull/6908) ([Zhichang Yu](https://github.com/yuzhichang))
+
+## ClickHouse Release 19.14 {#clickhouse-release-19-14}
+
+### ClickHouse Release 19.14.7.15, 2019-10-02 {#clickhouse-release-19-14-7-15-2019-10-02}
+
+#### Bug Fix {#bug-fix-6}
+
+-   This release also contains all bug fixes from 19.11.12.69.
+-   Fixed compatibility for distributed queries between 19.14 and earlier versions. This fixes [#7068](https://github.com/ClickHouse/ClickHouse/issues/7068). [#7069](https://github.com/ClickHouse/ClickHouse/pull/7069) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.14.6.12, 2019-09-19 {#clickhouse-release-19-14-6-12-2019-09-19}
+
+#### Bug Fix {#bug-fix-7}
+
+-   Fix for function `АrrayEnumerateUniqRanked` with empty arrays in params. [#6928](https://github.com/ClickHouse/ClickHouse/pull/6928) ([proller](https://github.com/proller))
+-   Fixed subquery name in queries with `ARRAY JOIN` and `GLOBAL IN subquery` with alias. Use subquery alias for external table name if it is specified. [#6934](https://github.com/ClickHouse/ClickHouse/pull/6934) ([Ivan](https://github.com/abyss7))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-3}
+
+-   Fix [flapping](https://clickhouse-test-reports.s3.yandex.net/6944/aab95fd5175a513413c7395a73a82044bdafb906/functional_stateless_tests_(debug).html) test `00715_fetch_merged_or_mutated_part_zookeeper` by rewriting it to a shell scripts because it needs to wait for mutations to apply. [#6977](https://github.com/ClickHouse/ClickHouse/pull/6977) ([Alexander Kazakov](https://github.com/Akazz))
+-   Fixed UBSan and MemSan failure in function `groupUniqArray` with emtpy array argument. It was caused by placing of empty `PaddedPODArray` into hash table zero cell because constructor for zero cell value was not called. [#6937](https://github.com/ClickHouse/ClickHouse/pull/6937) ([Amos Bird](https://github.com/amosbird))
+
+### ClickHouse Release 19.14.3.3, 2019-09-10 {#clickhouse-release-19-14-3-3-2019-09-10}
+
+#### New Feature {#new-feature-4}
+
+-   `WITH FILL` modifier for `ORDER BY`. (continuation of [#5069](https://github.com/ClickHouse/ClickHouse/issues/5069)) [#6610](https://github.com/ClickHouse/ClickHouse/pull/6610) ([Anton Popov](https://github.com/CurtizJ))
+-   `WITH TIES` modifier for `LIMIT`. (continuation of [#5069](https://github.com/ClickHouse/ClickHouse/issues/5069)) [#6610](https://github.com/ClickHouse/ClickHouse/pull/6610) ([Anton Popov](https://github.com/CurtizJ))
+-   Parse unquoted `NULL` literal as NULL (if setting `format_csv_unquoted_null_literal_as_null=1`). Initialize null fields with default values if data type of this field is not nullable (if setting `input_format_null_as_default=1`). [#5990](https://github.com/ClickHouse/ClickHouse/issues/5990) [#6055](https://github.com/ClickHouse/ClickHouse/pull/6055) ([tavplubix](https://github.com/tavplubix))
+-   Support for wildcards in paths of table functions `file` and `hdfs`. If the path contains wildcards, the table will be readonly. Example of usage: `select * from hdfs('hdfs://hdfs1:9000/some_dir/another_dir/*/file{0..9}{0..9}')` and `select * from file('some_dir/{some_file,another_file,yet_another}.tsv', 'TSV', 'value UInt32')`. [#6092](https://github.com/ClickHouse/ClickHouse/pull/6092) ([Olga Khvostikova](https://github.com/stavrolia))
+-   New `system.metric_log` table which stores values of `system.events` and `system.metrics` with specified time interval. [#6363](https://github.com/ClickHouse/ClickHouse/issues/6363) [#6467](https://github.com/ClickHouse/ClickHouse/pull/6467) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)) [#6530](https://github.com/ClickHouse/ClickHouse/pull/6530) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Allow to write ClickHouse text logs to `system.text_log` table. [#6037](https://github.com/ClickHouse/ClickHouse/issues/6037) [#6103](https://github.com/ClickHouse/ClickHouse/pull/6103) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)) [#6164](https://github.com/ClickHouse/ClickHouse/pull/6164) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Show private symbols in stack traces (this is done via parsing symbol tables of ELF files). Added information about file and line number in stack traces if debug info is present. Speedup symbol name lookup with indexing symbols present in program. Added new SQL functions for introspection: `demangle` and `addressToLine`. Renamed function `symbolizeAddress` to `addressToSymbol` for consistency. Function `addressToSymbol` will return mangled name for performance reasons and you have to apply `demangle`. Added setting `allow_introspection_functions` which is turned off by default. [#6201](https://github.com/ClickHouse/ClickHouse/pull/6201) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Table function `values` (the name is case-insensitive). It allows to read from `VALUES` list proposed in [#5984](https://github.com/ClickHouse/ClickHouse/issues/5984). Example: `SELECT * FROM VALUES('a UInt64, s String', (1, 'one'), (2, 'two'), (3, 'three'))`. [#6217](https://github.com/ClickHouse/ClickHouse/issues/6217). [#6209](https://github.com/ClickHouse/ClickHouse/pull/6209) ([dimarub2000](https://github.com/dimarub2000))
+-   Added an ability to alter storage settings. Syntax: `ALTER TABLE <table> MODIFY SETTING <setting> = <value>`. [#6366](https://github.com/ClickHouse/ClickHouse/pull/6366) [#6669](https://github.com/ClickHouse/ClickHouse/pull/6669) [#6685](https://github.com/ClickHouse/ClickHouse/pull/6685) ([alesapin](https://github.com/alesapin))
+-   Support for removing of detached parts. Syntax: `ALTER TABLE <table_name> DROP DETACHED PART '<part_id>'`. [#6158](https://github.com/ClickHouse/ClickHouse/pull/6158) ([tavplubix](https://github.com/tavplubix))
+-   Table constraints. Allows to add constraint to table definition which will be checked at insert. [#5273](https://github.com/ClickHouse/ClickHouse/pull/5273) ([Gleb Novikov](https://github.com/NanoBjorn)) [#6652](https://github.com/ClickHouse/ClickHouse/pull/6652) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Suppport for cascaded materialized views. [#6324](https://github.com/ClickHouse/ClickHouse/pull/6324) ([Amos Bird](https://github.com/amosbird))
+-   Turn on query profiler by default to sample every query execution thread once a second. [#6283](https://github.com/ClickHouse/ClickHouse/pull/6283) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Input format `ORC`. [#6454](https://github.com/ClickHouse/ClickHouse/pull/6454) [#6703](https://github.com/ClickHouse/ClickHouse/pull/6703) ([akonyaev90](https://github.com/akonyaev90))
+-   Added two new functions: `sigmoid` and `tanh` (that are useful for machine learning applications). [#6254](https://github.com/ClickHouse/ClickHouse/pull/6254) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Function `hasToken(haystack, token)`, `hasTokenCaseInsensitive(haystack, token)` to check if given token is in haystack. Token is a maximal length substring between two non alphanumeric ASCII characters (or boundaries of haystack). Token must be a constant string. Supported by tokenbf_v1 index specialization. [#6596](https://github.com/ClickHouse/ClickHouse/pull/6596), [#6662](https://github.com/ClickHouse/ClickHouse/pull/6662) ([Vasily Nemkov](https://github.com/Enmk))
+-   New function `neighbor(value, offset[, default_value])`. Allows to reach prev/next value within column in a block of data. [#5925](https://github.com/ClickHouse/ClickHouse/pull/5925) ([Alex Krash](https://github.com/alex-krash)) [6685365ab8c5b74f9650492c88a012596eb1b0c6](https://github.com/ClickHouse/ClickHouse/commit/6685365ab8c5b74f9650492c88a012596eb1b0c6) [341e2e4587a18065c2da1ca888c73389f48ce36c](https://github.com/ClickHouse/ClickHouse/commit/341e2e4587a18065c2da1ca888c73389f48ce36c) [Alexey Milovidov](https://github.com/alexey-milovidov)
+-   Created a function `currentUser()`, returning login of authorized user. Added alias `user()` for compatibility with MySQL. [#6470](https://github.com/ClickHouse/ClickHouse/pull/6470) ([Alex Krash](https://github.com/alex-krash))
+-   New aggregate functions `quantilesExactInclusive` and `quantilesExactExclusive` which were proposed in [#5885](https://github.com/ClickHouse/ClickHouse/issues/5885). [#6477](https://github.com/ClickHouse/ClickHouse/pull/6477) ([dimarub2000](https://github.com/dimarub2000))
+-   Function `bitmapRange(bitmap, range_begin, range_end)` which returns new set with specified range (not include the `range_end`). [#6314](https://github.com/ClickHouse/ClickHouse/pull/6314) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Function `geohashesInBox(longitude_min, latitude_min, longitude_max, latitude_max, precision)` which creates array of precision-long strings of geohash-boxes covering provided area. [#6127](https://github.com/ClickHouse/ClickHouse/pull/6127) ([Vasily Nemkov](https://github.com/Enmk))
+-   Implement support for INSERT query with `Kafka` tables. [#6012](https://github.com/ClickHouse/ClickHouse/pull/6012) ([Ivan](https://github.com/abyss7))
+-   Added support for `_partition` and `_timestamp` virtual columns to Kafka engine. [#6400](https://github.com/ClickHouse/ClickHouse/pull/6400) ([Ivan](https://github.com/abyss7))
+-   Possibility to remove sensitive data from `query_log`, server logs, process list with regexp-based rules. [#5710](https://github.com/ClickHouse/ClickHouse/pull/5710) ([filimonov](https://github.com/filimonov))
+
+#### Experimental Feature {#experimental-feature-2}
+
+-   Input and output data format `Template`. It allows to specify custom format string for input and output. [#4354](https://github.com/ClickHouse/ClickHouse/issues/4354) [#6727](https://github.com/ClickHouse/ClickHouse/pull/6727) ([tavplubix](https://github.com/tavplubix))
+-   Implementation of `LIVE VIEW` tables that were originally proposed in [#2898](https://github.com/ClickHouse/ClickHouse/pull/2898), prepared in [#3925](https://github.com/ClickHouse/ClickHouse/issues/3925), and then updated in [#5541](https://github.com/ClickHouse/ClickHouse/issues/5541). See [#5541](https://github.com/ClickHouse/ClickHouse/issues/5541) for detailed description. [#5541](https://github.com/ClickHouse/ClickHouse/issues/5541) ([vzakaznikov](https://github.com/vzakaznikov)) [#6425](https://github.com/ClickHouse/ClickHouse/pull/6425) ([Nikolai Kochetov](https://github.com/KochetovNicolai)) [#6656](https://github.com/ClickHouse/ClickHouse/pull/6656) ([vzakaznikov](https://github.com/vzakaznikov)) Note that `LIVE VIEW` feature may be removed in next versions.
+
+#### Bug Fix {#bug-fix-8}
+
+-   This release also contains all bug fixes from 19.13 and 19.11.
+-   Fix segmentation fault when the table has skip indices and vertical merge happens. [#6723](https://github.com/ClickHouse/ClickHouse/pull/6723) ([alesapin](https://github.com/alesapin))
+-   Fix per-column TTL with non-trivial column defaults. Previously in case of force TTL merge with `OPTIMIZE ... FINAL` query, expired values was replaced by type defaults instead of user-specified column defaults. [#6796](https://github.com/ClickHouse/ClickHouse/pull/6796) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix Kafka messages duplication problem on normal server restart. [#6597](https://github.com/ClickHouse/ClickHouse/pull/6597) ([Ivan](https://github.com/abyss7))
+-   Fixed infinite loop when reading Kafka messages. Do not pause/resume consumer on subscription at all - otherwise it may get paused indefinitely in some scenarios. [#6354](https://github.com/ClickHouse/ClickHouse/pull/6354) ([Ivan](https://github.com/abyss7))
+-   Fix `Key expression contains comparison between inconvertible types` exception in `bitmapContains` function. [#6136](https://github.com/ClickHouse/ClickHouse/issues/6136) [#6146](https://github.com/ClickHouse/ClickHouse/issues/6146) [#6156](https://github.com/ClickHouse/ClickHouse/pull/6156) ([dimarub2000](https://github.com/dimarub2000))
+-   Fix segfault with enabled `optimize_skip_unused_shards` and missing sharding key. [#6384](https://github.com/ClickHouse/ClickHouse/pull/6384) ([Anton Popov](https://github.com/CurtizJ))
+-   Fixed wrong code in mutations that may lead to memory corruption. Fixed segfault with read of address `0x14c0` that may happed due to concurrent `DROP TABLE` and `SELECT` from `system.parts` or `system.parts_columns`. Fixed race condition in preparation of mutation queries. Fixed deadlock caused by `OPTIMIZE` of Replicated tables and concurrent modification operations like ALTERs. [#6514](https://github.com/ClickHouse/ClickHouse/pull/6514) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Removed extra verbose logging in MySQL interface [#6389](https://github.com/ClickHouse/ClickHouse/pull/6389) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Return the ability to parse boolean settings from ‘true’ and ‘false’ in the configuration file. [#6278](https://github.com/ClickHouse/ClickHouse/pull/6278) ([alesapin](https://github.com/alesapin))
+-   Fix crash in `quantile` and `median` function over `Nullable(Decimal128)`. [#6378](https://github.com/ClickHouse/ClickHouse/pull/6378) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed possible incomplete result returned by `SELECT` query with `WHERE` condition on primary key contained conversion to Float type. It was caused by incorrect checking of monotonicity in `toFloat` function. [#6248](https://github.com/ClickHouse/ClickHouse/issues/6248) [#6374](https://github.com/ClickHouse/ClickHouse/pull/6374) ([dimarub2000](https://github.com/dimarub2000))
+-   Check `max_expanded_ast_elements` setting for mutations. Clear mutations after `TRUNCATE TABLE`. [#6205](https://github.com/ClickHouse/ClickHouse/pull/6205) ([Winter Zhang](https://github.com/zhang2014))
+-   Fix JOIN results for key columns when used with `join_use_nulls`. Attach Nulls instead of columns defaults. [#6249](https://github.com/ClickHouse/ClickHouse/pull/6249) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix for skip indices with vertical merge and alter. Fix for `Bad size of marks file` exception. [#6594](https://github.com/ClickHouse/ClickHouse/issues/6594) [#6713](https://github.com/ClickHouse/ClickHouse/pull/6713) ([alesapin](https://github.com/alesapin))
+-   Fix rare crash in `ALTER MODIFY COLUMN` and vertical merge when one of merged/altered parts is empty (0 rows) [#6746](https://github.com/ClickHouse/ClickHouse/issues/6746) [#6780](https://github.com/ClickHouse/ClickHouse/pull/6780) ([alesapin](https://github.com/alesapin))
+-   Fixed bug in conversion of `LowCardinality` types in `AggregateFunctionFactory`. This fixes [#6257](https://github.com/ClickHouse/ClickHouse/issues/6257). [#6281](https://github.com/ClickHouse/ClickHouse/pull/6281) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix wrong behavior and possible segfaults in `topK` and `topKWeighted` aggregated functions. [#6404](https://github.com/ClickHouse/ClickHouse/pull/6404) ([Anton Popov](https://github.com/CurtizJ))
+-   Fixed unsafe code around `getIdentifier` function. [#6401](https://github.com/ClickHouse/ClickHouse/issues/6401) [#6409](https://github.com/ClickHouse/ClickHouse/pull/6409) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed bug in MySQL wire protocol (is used while connecting to ClickHouse form MySQL client). Caused by heap buffer overflow in `PacketPayloadWriteBuffer`. [#6212](https://github.com/ClickHouse/ClickHouse/pull/6212) ([Yuriy Baranov](https://github.com/yurriy))
+-   Fixed memory leak in `bitmapSubsetInRange` function. [#6819](https://github.com/ClickHouse/ClickHouse/pull/6819) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Fix rare bug when mutation executed after granularity change. [#6816](https://github.com/ClickHouse/ClickHouse/pull/6816) ([alesapin](https://github.com/alesapin))
+-   Allow protobuf message with all fields by default. [#6132](https://github.com/ClickHouse/ClickHouse/pull/6132) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Resolve a bug with `nullIf` function when we send a `NULL` argument on the second argument. [#6446](https://github.com/ClickHouse/ClickHouse/pull/6446) ([Guillaume Tassery](https://github.com/YiuRULE))
+-   Fix rare bug with wrong memory allocation/deallocation in complex key cache dictionaries with string fields which leads to infinite memory consumption (looks like memory leak). Bug reproduces when string size was a power of two starting from eight (8, 16, 32, etc). [#6447](https://github.com/ClickHouse/ClickHouse/pull/6447) ([alesapin](https://github.com/alesapin))
+-   Fixed Gorilla encoding on small sequences which caused exception `Cannot write after end of buffer`. [#6398](https://github.com/ClickHouse/ClickHouse/issues/6398) [#6444](https://github.com/ClickHouse/ClickHouse/pull/6444) ([Vasily Nemkov](https://github.com/Enmk))
+-   Allow to use not nullable types in JOINs with `join_use_nulls` enabled. [#6705](https://github.com/ClickHouse/ClickHouse/pull/6705) ([Artem Zuikov](https://github.com/4ertus2))
+-   Disable `Poco::AbstractConfiguration` substitutions in query in `clickhouse-client`. [#6706](https://github.com/ClickHouse/ClickHouse/pull/6706) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Avoid deadlock in `REPLACE PARTITION`. [#6677](https://github.com/ClickHouse/ClickHouse/pull/6677) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Using `arrayReduce` for constant arguments may lead to segfault. [#6242](https://github.com/ClickHouse/ClickHouse/issues/6242) [#6326](https://github.com/ClickHouse/ClickHouse/pull/6326) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix inconsistent parts which can appear if replica was restored after `DROP PARTITION`. [#6522](https://github.com/ClickHouse/ClickHouse/issues/6522) [#6523](https://github.com/ClickHouse/ClickHouse/pull/6523) ([tavplubix](https://github.com/tavplubix))
+-   Fixed hang in `JSONExtractRaw` function. [#6195](https://github.com/ClickHouse/ClickHouse/issues/6195) [#6198](https://github.com/ClickHouse/ClickHouse/pull/6198) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix bug with incorrect skip indices serialization and aggregation with adaptive granularity. [#6594](https://github.com/ClickHouse/ClickHouse/issues/6594). [#6748](https://github.com/ClickHouse/ClickHouse/pull/6748) ([alesapin](https://github.com/alesapin))
+-   Fix `WITH ROLLUP` and `WITH CUBE` modifiers of `GROUP BY` with two-level aggregation. [#6225](https://github.com/ClickHouse/ClickHouse/pull/6225) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix bug with writing secondary indices marks with adaptive granularity. [#6126](https://github.com/ClickHouse/ClickHouse/pull/6126) ([alesapin](https://github.com/alesapin))
+-   Fix initialization order while server startup. Since `StorageMergeTree::background_task_handle` is initialized in `startup()` the `MergeTreeBlockOutputStream::write()` may try to use it before initialization. Just check if it is initialized. [#6080](https://github.com/ClickHouse/ClickHouse/pull/6080) ([Ivan](https://github.com/abyss7))
+-   Clearing the data buffer from the previous read operation that was completed with an error. [#6026](https://github.com/ClickHouse/ClickHouse/pull/6026) ([Nikolay](https://github.com/bopohaa))
+-   Fix bug with enabling adaptive granularity when creating a new replica for Replicated\*MergeTree table. [#6394](https://github.com/ClickHouse/ClickHouse/issues/6394) [#6452](https://github.com/ClickHouse/ClickHouse/pull/6452) ([alesapin](https://github.com/alesapin))
+-   Fixed possible crash during server startup in case of exception happened in `libunwind` during exception at access to uninitialized `ThreadStatus` structure. [#6456](https://github.com/ClickHouse/ClickHouse/pull/6456) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+-   Fix crash in `yandexConsistentHash` function. Found by fuzz test. [#6304](https://github.com/ClickHouse/ClickHouse/issues/6304) [#6305](https://github.com/ClickHouse/ClickHouse/pull/6305) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed the possibility of hanging queries when server is overloaded and global thread pool becomes near full. This have higher chance to happen on clusters with large number of shards (hundreds), because distributed queries allocate a thread per connection to each shard. For example, this issue may reproduce if a cluster of 330 shards is processing 30 concurrent distributed queries. This issue affects all versions starting from 19.2. [#6301](https://github.com/ClickHouse/ClickHouse/pull/6301) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed logic of `arrayEnumerateUniqRanked` function. [#6423](https://github.com/ClickHouse/ClickHouse/pull/6423) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix segfault when decoding symbol table. [#6603](https://github.com/ClickHouse/ClickHouse/pull/6603) ([Amos Bird](https://github.com/amosbird))
+-   Fixed irrelevant exception in cast of `LowCardinality(Nullable)` to not-Nullable column in case if it does not contain Nulls (e.g. in query like `SELECT CAST(CAST('Hello' AS LowCardinality(Nullable(String))) AS String)`. [#6094](https://github.com/ClickHouse/ClickHouse/issues/6094) [#6119](https://github.com/ClickHouse/ClickHouse/pull/6119) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Removed extra quoting of description in `system.settings` table. [#6696](https://github.com/ClickHouse/ClickHouse/issues/6696) [#6699](https://github.com/ClickHouse/ClickHouse/pull/6699) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Avoid possible deadlock in `TRUNCATE` of Replicated table. [#6695](https://github.com/ClickHouse/ClickHouse/pull/6695) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix reading in order of sorting key. [#6189](https://github.com/ClickHouse/ClickHouse/pull/6189) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix `ALTER TABLE ... UPDATE` query for tables with `enable_mixed_granularity_parts=1`. [#6543](https://github.com/ClickHouse/ClickHouse/pull/6543) ([alesapin](https://github.com/alesapin))
+-   Fix bug opened by [#4405](https://github.com/ClickHouse/ClickHouse/pull/4405) (since 19.4.0). Reproduces in queries to Distributed tables over MergeTree tables when we does not query any columns (`SELECT 1`). [#6236](https://github.com/ClickHouse/ClickHouse/pull/6236) ([alesapin](https://github.com/alesapin))
+-   Fixed overflow in integer division of signed type to unsigned type. The behaviour was exactly as in C or C++ language (integer promotion rules) that may be surprising. Please note that the overflow is still possible when dividing large signed number to large unsigned number or vice-versa (but that case is less usual). The issue existed in all server versions. [#6214](https://github.com/ClickHouse/ClickHouse/issues/6214) [#6233](https://github.com/ClickHouse/ClickHouse/pull/6233) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Limit maximum sleep time for throttling when `max_execution_speed` or `max_execution_speed_bytes` is set. Fixed false errors like `Estimated query execution time (inf seconds) is too long`. [#5547](https://github.com/ClickHouse/ClickHouse/issues/5547) [#6232](https://github.com/ClickHouse/ClickHouse/pull/6232) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed issues about using `MATERIALIZED` columns and aliases in `MaterializedView`. [#448](https://github.com/ClickHouse/ClickHouse/issues/448) [#3484](https://github.com/ClickHouse/ClickHouse/issues/3484) [#3450](https://github.com/ClickHouse/ClickHouse/issues/3450) [#2878](https://github.com/ClickHouse/ClickHouse/issues/2878) [#2285](https://github.com/ClickHouse/ClickHouse/issues/2285) [#3796](https://github.com/ClickHouse/ClickHouse/pull/3796) ([Amos Bird](https://github.com/amosbird)) [#6316](https://github.com/ClickHouse/ClickHouse/pull/6316) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix `FormatFactory` behaviour for input streams which are not implemented as processor. [#6495](https://github.com/ClickHouse/ClickHouse/pull/6495) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fixed typo. [#6631](https://github.com/ClickHouse/ClickHouse/pull/6631) ([Alex Ryndin](https://github.com/alexryndin))
+-   Typo in the error message ( is -\> are ). [#6839](https://github.com/ClickHouse/ClickHouse/pull/6839) ([Denis Zhuravlev](https://github.com/den-crane))
+-   Fixed error while parsing of columns list from string if type contained a comma (this issue was relevant for `File`, `URL`, `HDFS` storages) [#6217](https://github.com/ClickHouse/ClickHouse/issues/6217). [#6209](https://github.com/ClickHouse/ClickHouse/pull/6209) ([dimarub2000](https://github.com/dimarub2000))
+
+#### Security Fix {#security-fix}
+
+-   This release also contains all bug security fixes from 19.13 and 19.11.
+-   Fixed the possibility of a fabricated query to cause server crash due to stack overflow in SQL parser. Fixed the possibility of stack overflow in Merge and Distributed tables, materialized views and conditions for row-level security that involve subqueries. [#6433](https://github.com/ClickHouse/ClickHouse/pull/6433) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Improvement {#improvement-3}
+
+-   Correct implementation of ternary logic for `AND/OR`. [#6048](https://github.com/ClickHouse/ClickHouse/pull/6048) ([Alexander Kazakov](https://github.com/Akazz))
+-   Now values and rows with expired TTL will be removed after `OPTIMIZE ... FINAL` query from old parts without TTL infos or with outdated TTL infos, e.g. after `ALTER ... MODIFY TTL` query. Added queries `SYSTEM STOP/START TTL MERGES` to disallow/allow assign merges with TTL and filter expired values in all merges. [#6274](https://github.com/ClickHouse/ClickHouse/pull/6274) ([Anton Popov](https://github.com/CurtizJ))
+-   Possibility to change the location of ClickHouse history file for client using `CLICKHOUSE_HISTORY_FILE` env. [#6840](https://github.com/ClickHouse/ClickHouse/pull/6840) ([filimonov](https://github.com/filimonov))
+-   Remove `dry_run` flag from `InterpreterSelectQuery`. … [#6375](https://github.com/ClickHouse/ClickHouse/pull/6375) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Support `ASOF JOIN` with `ON` section. [#6211](https://github.com/ClickHouse/ClickHouse/pull/6211) ([Artem Zuikov](https://github.com/4ertus2))
+-   Better support of skip indexes for mutations and replication. Support for `MATERIALIZE/CLEAR INDEX ... IN PARTITION` query. `UPDATE x = x` recalculates all indices that use column `x`. [#5053](https://github.com/ClickHouse/ClickHouse/pull/5053) ([Nikita Vasilev](https://github.com/nikvas0))
+-   Allow to `ATTACH` live views (for example, at the server startup) regardless to `allow_experimental_live_view` setting. [#6754](https://github.com/ClickHouse/ClickHouse/pull/6754) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   For stack traces gathered by query profiler, do not include stack frames generated by the query profiler itself. [#6250](https://github.com/ClickHouse/ClickHouse/pull/6250) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Now table functions `values`, `file`, `url`, `hdfs` have support for ALIAS columns. [#6255](https://github.com/ClickHouse/ClickHouse/pull/6255) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Throw an exception if `config.d` file does not have the corresponding root element as the config file. [#6123](https://github.com/ClickHouse/ClickHouse/pull/6123) ([dimarub2000](https://github.com/dimarub2000))
+-   Print extra info in exception message for `no space left on device`. [#6182](https://github.com/ClickHouse/ClickHouse/issues/6182), [#6252](https://github.com/ClickHouse/ClickHouse/issues/6252) [#6352](https://github.com/ClickHouse/ClickHouse/pull/6352) ([tavplubix](https://github.com/tavplubix))
+-   When determining shards of a `Distributed` table to be covered by a read query (for `optimize_skip_unused_shards` = 1) ClickHouse now checks conditions from both `prewhere` and `where` clauses of select statement. [#6521](https://github.com/ClickHouse/ClickHouse/pull/6521) ([Alexander Kazakov](https://github.com/Akazz))
+-   Enabled `SIMDJSON` for machines without AVX2 but with SSE 4.2 and PCLMUL instruction set. [#6285](https://github.com/ClickHouse/ClickHouse/issues/6285) [#6320](https://github.com/ClickHouse/ClickHouse/pull/6320) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   ClickHouse can work on filesystems without `O_DIRECT` support (such as ZFS and BtrFS) without additional tuning. [#4449](https://github.com/ClickHouse/ClickHouse/issues/4449) [#6730](https://github.com/ClickHouse/ClickHouse/pull/6730) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Support push down predicate for final subquery. [#6120](https://github.com/ClickHouse/ClickHouse/pull/6120) ([TCeason](https://github.com/TCeason)) [#6162](https://github.com/ClickHouse/ClickHouse/pull/6162) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Better `JOIN ON` keys extraction [#6131](https://github.com/ClickHouse/ClickHouse/pull/6131) ([Artem Zuikov](https://github.com/4ertus2))
+-   Upated `SIMDJSON`. [#6285](https://github.com/ClickHouse/ClickHouse/issues/6285). [#6306](https://github.com/ClickHouse/ClickHouse/pull/6306) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Optimize selecting of smallest column for `SELECT count()` query. [#6344](https://github.com/ClickHouse/ClickHouse/pull/6344) ([Amos Bird](https://github.com/amosbird))
+-   Added `strict` parameter in `windowFunnel()`. When the `strict` is set, the `windowFunnel()` applies conditions only for the unique values. [#6548](https://github.com/ClickHouse/ClickHouse/pull/6548) ([achimbab](https://github.com/achimbab))
+-   Safer interface of `mysqlxx::Pool`. [#6150](https://github.com/ClickHouse/ClickHouse/pull/6150) ([avasiliev](https://github.com/avasiliev))
+-   Options line size when executing with `--help` option now corresponds with terminal size. [#6590](https://github.com/ClickHouse/ClickHouse/pull/6590) ([dimarub2000](https://github.com/dimarub2000))
+-   Disable “read in order” optimization for aggregation without keys. [#6599](https://github.com/ClickHouse/ClickHouse/pull/6599) ([Anton Popov](https://github.com/CurtizJ))
+-   HTTP status code for `INCORRECT_DATA` and `TYPE_MISMATCH` error codes was changed from default `500 Internal Server Error` to `400 Bad Request`. [#6271](https://github.com/ClickHouse/ClickHouse/pull/6271) ([Alexander Rodin](https://github.com/a-rodin))
+-   Move Join object from `ExpressionAction` into `AnalyzedJoin`. `ExpressionAnalyzer` and `ExpressionAction` do not know about `Join` class anymore. Its logic is hidden by `AnalyzedJoin` iface. [#6801](https://github.com/ClickHouse/ClickHouse/pull/6801) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed possible deadlock of distributed queries when one of shards is localhost but the query is sent via network connection. [#6759](https://github.com/ClickHouse/ClickHouse/pull/6759) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Changed semantic of multiple tables `RENAME` to avoid possible deadlocks. [#6757](https://github.com/ClickHouse/ClickHouse/issues/6757). [#6756](https://github.com/ClickHouse/ClickHouse/pull/6756) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Rewritten MySQL compatibility server to prevent loading full packet payload in memory. Decreased memory consumption for each connection to approximately `2 * DBMS_DEFAULT_BUFFER_SIZE` (read/write buffers). [#5811](https://github.com/ClickHouse/ClickHouse/pull/5811) ([Yuriy Baranov](https://github.com/yurriy))
+-   Move AST alias interpreting logic out of parser that does not have to know anything about query semantics. [#6108](https://github.com/ClickHouse/ClickHouse/pull/6108) ([Artem Zuikov](https://github.com/4ertus2))
+-   Slightly more safe parsing of `NamesAndTypesList`. [#6408](https://github.com/ClickHouse/ClickHouse/issues/6408). [#6410](https://github.com/ClickHouse/ClickHouse/pull/6410) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   `clickhouse-copier`: Allow use `where_condition` from config with `partition_key` alias in query for checking partition existence (Earlier it was used only in reading data queries). [#6577](https://github.com/ClickHouse/ClickHouse/pull/6577) ([proller](https://github.com/proller))
+-   Added optional message argument in `throwIf`. ([#5772](https://github.com/ClickHouse/ClickHouse/issues/5772)) [#6329](https://github.com/ClickHouse/ClickHouse/pull/6329) ([Vdimir](https://github.com/Vdimir))
+-   Server exception got while sending insertion data is now being processed in client as well. [#5891](https://github.com/ClickHouse/ClickHouse/issues/5891) [#6711](https://github.com/ClickHouse/ClickHouse/pull/6711) ([dimarub2000](https://github.com/dimarub2000))
+-   Added a metric `DistributedFilesToInsert` that shows the total number of files in filesystem that are selected to send to remote servers by Distributed tables. The number is summed across all shards. [#6600](https://github.com/ClickHouse/ClickHouse/pull/6600) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Move most of JOINs prepare logic from `ExpressionAction/ExpressionAnalyzer` to `AnalyzedJoin`. [#6785](https://github.com/ClickHouse/ClickHouse/pull/6785) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix TSan [warning](https://clickhouse-test-reports.s3.yandex.net/6399/c1c1d1daa98e199e620766f1bd06a5921050a00d/functional_stateful_tests_(thread).html) ‘lock-order-inversion’. [#6740](https://github.com/ClickHouse/ClickHouse/pull/6740) ([Vasily Nemkov](https://github.com/Enmk))
+-   Better information messages about lack of Linux capabilities. Logging fatal errors with “fatal” level, that will make it easier to find in `system.text_log`. [#6441](https://github.com/ClickHouse/ClickHouse/pull/6441) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   When enable dumping temporary data to the disk to restrict memory usage during `GROUP BY`, `ORDER BY`, it didn’t check the free disk space. The fix add a new setting `min_free_disk_space`, when the free disk space it smaller then the threshold, the query will stop and throw `ErrorCodes::NOT_ENOUGH_SPACE`. [#6678](https://github.com/ClickHouse/ClickHouse/pull/6678) ([Weiqing Xu](https://github.com/weiqxu)) [#6691](https://github.com/ClickHouse/ClickHouse/pull/6691) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Removed recursive rwlock by thread. It makes no sense, because threads are reused between queries. `SELECT` query may acquire a lock in one thread, hold a lock from another thread and exit from first thread. In the same time, first thread can be reused by `DROP` query. This will lead to false “Attempt to acquire exclusive lock recursively” messages. [#6771](https://github.com/ClickHouse/ClickHouse/pull/6771) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Split `ExpressionAnalyzer.appendJoin()`. Prepare a place in `ExpressionAnalyzer` for `MergeJoin`. [#6524](https://github.com/ClickHouse/ClickHouse/pull/6524) ([Artem Zuikov](https://github.com/4ertus2))
+-   Added `mysql_native_password` authentication plugin to MySQL compatibility server. [#6194](https://github.com/ClickHouse/ClickHouse/pull/6194) ([Yuriy Baranov](https://github.com/yurriy))
+-   Less number of `clock_gettime` calls; fixed ABI compatibility between debug/release in `Allocator` (insignificant issue). [#6197](https://github.com/ClickHouse/ClickHouse/pull/6197) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Move `collectUsedColumns` from `ExpressionAnalyzer` to `SyntaxAnalyzer`. `SyntaxAnalyzer` makes `required_source_columns` itself now. [#6416](https://github.com/ClickHouse/ClickHouse/pull/6416) ([Artem Zuikov](https://github.com/4ertus2))
+-   Add setting `joined_subquery_requires_alias` to require aliases for subselects and table functions in `FROM` that more than one table is present (i.e. queries with JOINs). [#6733](https://github.com/ClickHouse/ClickHouse/pull/6733) ([Artem Zuikov](https://github.com/4ertus2))
+-   Extract `GetAggregatesVisitor` class from `ExpressionAnalyzer`. [#6458](https://github.com/ClickHouse/ClickHouse/pull/6458) ([Artem Zuikov](https://github.com/4ertus2))
+-   `system.query_log`: change data type of `type` column to `Enum`. [#6265](https://github.com/ClickHouse/ClickHouse/pull/6265) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+-   Static linking of `sha256_password` authentication plugin. [#6512](https://github.com/ClickHouse/ClickHouse/pull/6512) ([Yuriy Baranov](https://github.com/yurriy))
+-   Avoid extra dependency for the setting `compile` to work. In previous versions, the user may get error like `cannot open crti.o`, `unable to find library -lc` etc. [#6309](https://github.com/ClickHouse/ClickHouse/pull/6309) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   More validation of the input that may come from malicious replica. [#6303](https://github.com/ClickHouse/ClickHouse/pull/6303) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Now `clickhouse-obfuscator` file is available in `clickhouse-client` package. In previous versions it was available as `clickhouse obfuscator` (with whitespace). [#5816](https://github.com/ClickHouse/ClickHouse/issues/5816) [#6609](https://github.com/ClickHouse/ClickHouse/pull/6609) ([dimarub2000](https://github.com/dimarub2000))
+-   Fixed deadlock when we have at least two queries that read at least two tables in different order and another query that performs DDL operation on one of tables. Fixed another very rare deadlock. [#6764](https://github.com/ClickHouse/ClickHouse/pull/6764) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added `os_thread_ids` column to `system.processes` and `system.query_log` for better debugging possibilities. [#6763](https://github.com/ClickHouse/ClickHouse/pull/6763) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   A workaround for PHP mysqlnd extension bugs which occur when `sha256_password` is used as a default authentication plugin (described in [#6031](https://github.com/ClickHouse/ClickHouse/issues/6031)). [#6113](https://github.com/ClickHouse/ClickHouse/pull/6113) ([Yuriy Baranov](https://github.com/yurriy))
+-   Remove unneeded place with changed nullability columns. [#6693](https://github.com/ClickHouse/ClickHouse/pull/6693) ([Artem Zuikov](https://github.com/4ertus2))
+-   Set default value of `queue_max_wait_ms` to zero, because current value (five seconds) makes no sense. There are rare circumstances when this settings has any use. Added settings `replace_running_query_max_wait_ms`, `kafka_max_wait_ms` and `connection_pool_max_wait_ms` for disambiguation. [#6692](https://github.com/ClickHouse/ClickHouse/pull/6692) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Extract `SelectQueryExpressionAnalyzer` from `ExpressionAnalyzer`. Keep the last one for non-select queries. [#6499](https://github.com/ClickHouse/ClickHouse/pull/6499) ([Artem Zuikov](https://github.com/4ertus2))
+-   Removed duplicating input and output formats. [#6239](https://github.com/ClickHouse/ClickHouse/pull/6239) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Allow user to override `poll_interval` and `idle_connection_timeout` settings on connection. [#6230](https://github.com/ClickHouse/ClickHouse/pull/6230) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   `MergeTree` now has an additional option `ttl_only_drop_parts` (disabled by default) to avoid partial pruning of parts, so that they dropped completely when all the rows in a part are expired. [#6191](https://github.com/ClickHouse/ClickHouse/pull/6191) ([Sergi Vladykin](https://github.com/svladykin))
+-   Type checks for set index functions. Throw exception if function got a wrong type. This fixes fuzz test with UBSan. [#6511](https://github.com/ClickHouse/ClickHouse/pull/6511) ([Nikita Vasilev](https://github.com/nikvas0))
+
+#### Performance Improvement {#performance-improvement-2}
+
+-   Optimize queries with `ORDER BY expressions` clause, where `expressions` have coinciding prefix with sorting key in `MergeTree` tables. This optimization is controlled by `optimize_read_in_order` setting. [#6054](https://github.com/ClickHouse/ClickHouse/pull/6054) [#6629](https://github.com/ClickHouse/ClickHouse/pull/6629) ([Anton Popov](https://github.com/CurtizJ))
+-   Allow to use multiple threads during parts loading and removal. [#6372](https://github.com/ClickHouse/ClickHouse/issues/6372) [#6074](https://github.com/ClickHouse/ClickHouse/issues/6074) [#6438](https://github.com/ClickHouse/ClickHouse/pull/6438) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Implemented batch variant of updating aggregate function states. It may lead to performance benefits. [#6435](https://github.com/ClickHouse/ClickHouse/pull/6435) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Using `FastOps` library for functions `exp`, `log`, `sigmoid`, `tanh`. FastOps is a fast vector math library from Michael Parakhin (Yandex CTO). Improved performance of `exp` and `log` functions more than 6 times. The functions `exp` and `log` from `Float32` argument will return `Float32` (in previous versions they always return `Float64`). Now `exp(nan)` may return `inf`. The result of `exp` and `log` functions may be not the nearest machine representable number to the true answer. [#6254](https://github.com/ClickHouse/ClickHouse/pull/6254) ([alexey-milovidov](https://github.com/alexey-milovidov)) Using Danila Kutenin variant to make fastops working [#6317](https://github.com/ClickHouse/ClickHouse/pull/6317) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Disable consecutive key optimization for `UInt8/16`. [#6298](https://github.com/ClickHouse/ClickHouse/pull/6298) [#6701](https://github.com/ClickHouse/ClickHouse/pull/6701) ([akuzm](https://github.com/akuzm))
+-   Improved performance of `simdjson` library by getting rid of dynamic allocation in `ParsedJson::Iterator`. [#6479](https://github.com/ClickHouse/ClickHouse/pull/6479) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Pre-fault pages when allocating memory with `mmap()`. [#6667](https://github.com/ClickHouse/ClickHouse/pull/6667) ([akuzm](https://github.com/akuzm))
+-   Fix performance bug in `Decimal` comparison. [#6380](https://github.com/ClickHouse/ClickHouse/pull/6380) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-4}
+
+-   Remove Compiler (runtime template instantiation) because we’ve win over it’s performance. [#6646](https://github.com/ClickHouse/ClickHouse/pull/6646) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added performance test to show degradation of performance in gcc-9 in more isolated way. [#6302](https://github.com/ClickHouse/ClickHouse/pull/6302) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added table function `numbers_mt`, which is multithreaded version of `numbers`. Updated performance tests with hash functions. [#6554](https://github.com/ClickHouse/ClickHouse/pull/6554) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Comparison mode in `clickhouse-benchmark` [#6220](https://github.com/ClickHouse/ClickHouse/issues/6220) [#6343](https://github.com/ClickHouse/ClickHouse/pull/6343) ([dimarub2000](https://github.com/dimarub2000))
+-   Best effort for printing stack traces. Also added `SIGPROF` as a debugging signal to print stack trace of a running thread. [#6529](https://github.com/ClickHouse/ClickHouse/pull/6529) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Every function in its own file, part 10. [#6321](https://github.com/ClickHouse/ClickHouse/pull/6321) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Remove doubled const `TABLE_IS_READ_ONLY`. [#6566](https://github.com/ClickHouse/ClickHouse/pull/6566) ([filimonov](https://github.com/filimonov))
+-   Formatting changes for `StringHashMap` PR [#5417](https://github.com/ClickHouse/ClickHouse/issues/5417). [#6700](https://github.com/ClickHouse/ClickHouse/pull/6700) ([akuzm](https://github.com/akuzm))
+-   Better subquery for join creation in `ExpressionAnalyzer`. [#6824](https://github.com/ClickHouse/ClickHouse/pull/6824) ([Artem Zuikov](https://github.com/4ertus2))
+-   Remove a redundant condition (found by PVS Studio). [#6775](https://github.com/ClickHouse/ClickHouse/pull/6775) ([akuzm](https://github.com/akuzm))
+-   Separate the hash table interface for `ReverseIndex`. [#6672](https://github.com/ClickHouse/ClickHouse/pull/6672) ([akuzm](https://github.com/akuzm))
+-   Refactoring of settings. [#6689](https://github.com/ClickHouse/ClickHouse/pull/6689) ([alesapin](https://github.com/alesapin))
+-   Add comments for `set` index functions. [#6319](https://github.com/ClickHouse/ClickHouse/pull/6319) ([Nikita Vasilev](https://github.com/nikvas0))
+-   Increase OOM score in debug version on Linux. [#6152](https://github.com/ClickHouse/ClickHouse/pull/6152) ([akuzm](https://github.com/akuzm))
+-   HDFS HA now work in debug build. [#6650](https://github.com/ClickHouse/ClickHouse/pull/6650) ([Weiqing Xu](https://github.com/weiqxu))
+-   Added a test to `transform_query_for_external_database`. [#6388](https://github.com/ClickHouse/ClickHouse/pull/6388) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add test for multiple materialized views for Kafka table. [#6509](https://github.com/ClickHouse/ClickHouse/pull/6509) ([Ivan](https://github.com/abyss7))
+-   Make a better build scheme. [#6500](https://github.com/ClickHouse/ClickHouse/pull/6500) ([Ivan](https://github.com/abyss7))
+-   Fixed `test_external_dictionaries` integration in case it was executed under non root user. [#6507](https://github.com/ClickHouse/ClickHouse/pull/6507) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   The bug reproduces when total size of written packets exceeds `DBMS_DEFAULT_BUFFER_SIZE`. [#6204](https://github.com/ClickHouse/ClickHouse/pull/6204) ([Yuriy Baranov](https://github.com/yurriy))
+-   Added a test for `RENAME` table race condition [#6752](https://github.com/ClickHouse/ClickHouse/pull/6752) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Avoid data race on Settings in `KILL QUERY`. [#6753](https://github.com/ClickHouse/ClickHouse/pull/6753) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add integration test for handling errors by a cache dictionary. [#6755](https://github.com/ClickHouse/ClickHouse/pull/6755) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Disable parsing of ELF object files on Mac OS, because it makes no sense. [#6578](https://github.com/ClickHouse/ClickHouse/pull/6578) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Attempt to make changelog generator better. [#6327](https://github.com/ClickHouse/ClickHouse/pull/6327) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Adding `-Wshadow` switch to the GCC. [#6325](https://github.com/ClickHouse/ClickHouse/pull/6325) ([kreuzerkrieg](https://github.com/kreuzerkrieg))
+-   Removed obsolete code for `mimalloc` support. [#6715](https://github.com/ClickHouse/ClickHouse/pull/6715) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   `zlib-ng` determines x86 capabilities and saves this info to global variables. This is done in defalteInit call, which may be made by different threads simultaneously. To avoid multithreaded writes, do it on library startup. [#6141](https://github.com/ClickHouse/ClickHouse/pull/6141) ([akuzm](https://github.com/akuzm))
+-   Regression test for a bug which in join which was fixed in [#5192](https://github.com/ClickHouse/ClickHouse/issues/5192). [#6147](https://github.com/ClickHouse/ClickHouse/pull/6147) ([Bakhtiyor Ruziev](https://github.com/theruziev))
+-   Fixed MSan report. [#6144](https://github.com/ClickHouse/ClickHouse/pull/6144) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix flapping TTL test. [#6782](https://github.com/ClickHouse/ClickHouse/pull/6782) ([Anton Popov](https://github.com/CurtizJ))
+-   Fixed false data race in `MergeTreeDataPart::is_frozen` field. [#6583](https://github.com/ClickHouse/ClickHouse/pull/6583) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed timeouts in fuzz test. In previous version, it managed to find false hangup in query `SELECT * FROM numbers_mt(gccMurmurHash(''))`. [#6582](https://github.com/ClickHouse/ClickHouse/pull/6582) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added debug checks to `static_cast` of columns. [#6581](https://github.com/ClickHouse/ClickHouse/pull/6581) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Support for Oracle Linux in official RPM packages. [#6356](https://github.com/ClickHouse/ClickHouse/issues/6356) [#6585](https://github.com/ClickHouse/ClickHouse/pull/6585) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Changed json perftests from `once` to `loop` type. [#6536](https://github.com/ClickHouse/ClickHouse/pull/6536) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   `odbc-bridge.cpp` defines `main()` so it should not be included in `clickhouse-lib`. [#6538](https://github.com/ClickHouse/ClickHouse/pull/6538) ([Orivej Desh](https://github.com/orivej))
+-   Test for crash in `FULL|RIGHT JOIN` with nulls in right table’s keys. [#6362](https://github.com/ClickHouse/ClickHouse/pull/6362) ([Artem Zuikov](https://github.com/4ertus2))
+-   Added a test for the limit on expansion of aliases just in case. [#6442](https://github.com/ClickHouse/ClickHouse/pull/6442) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Switched from `boost::filesystem` to `std::filesystem` where appropriate. [#6253](https://github.com/ClickHouse/ClickHouse/pull/6253) [#6385](https://github.com/ClickHouse/ClickHouse/pull/6385) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added RPM packages to website. [#6251](https://github.com/ClickHouse/ClickHouse/pull/6251) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add a test for fixed `Unknown identifier` exception in `IN` section. [#6708](https://github.com/ClickHouse/ClickHouse/pull/6708) ([Artem Zuikov](https://github.com/4ertus2))
+-   Simplify `shared_ptr_helper` because people facing difficulties understanding it. [#6675](https://github.com/ClickHouse/ClickHouse/pull/6675) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added performance tests for fixed Gorilla and DoubleDelta codec. [#6179](https://github.com/ClickHouse/ClickHouse/pull/6179) ([Vasily Nemkov](https://github.com/Enmk))
+-   Split the integration test `test_dictionaries` into 4 separate tests. [#6776](https://github.com/ClickHouse/ClickHouse/pull/6776) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fix PVS-Studio warning in `PipelineExecutor`. [#6777](https://github.com/ClickHouse/ClickHouse/pull/6777) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Allow to use `library` dictionary source with ASan. [#6482](https://github.com/ClickHouse/ClickHouse/pull/6482) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added option to generate changelog from a list of PRs. [#6350](https://github.com/ClickHouse/ClickHouse/pull/6350) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Lock the `TinyLog` storage when reading. [#6226](https://github.com/ClickHouse/ClickHouse/pull/6226) ([akuzm](https://github.com/akuzm))
+-   Check for broken symlinks in CI. [#6634](https://github.com/ClickHouse/ClickHouse/pull/6634) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Increase timeout for “stack overflow” test because it may take a long time in debug build. [#6637](https://github.com/ClickHouse/ClickHouse/pull/6637) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added a check for double whitespaces. [#6643](https://github.com/ClickHouse/ClickHouse/pull/6643) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix `new/delete` memory tracking when build with sanitizers. Tracking is not clear. It only prevents memory limit exceptions in tests. [#6450](https://github.com/ClickHouse/ClickHouse/pull/6450) ([Artem Zuikov](https://github.com/4ertus2))
+-   Enable back the check of undefined symbols while linking. [#6453](https://github.com/ClickHouse/ClickHouse/pull/6453) ([Ivan](https://github.com/abyss7))
+-   Avoid rebuilding `hyperscan` every day. [#6307](https://github.com/ClickHouse/ClickHouse/pull/6307) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed UBSan report in `ProtobufWriter`. [#6163](https://github.com/ClickHouse/ClickHouse/pull/6163) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Don’t allow to use query profiler with sanitizers because it is not compatible. [#6769](https://github.com/ClickHouse/ClickHouse/pull/6769) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add test for reloading a dictionary after fail by timer. [#6114](https://github.com/ClickHouse/ClickHouse/pull/6114) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fix inconsistency in `PipelineExecutor::prepareProcessor` argument type. [#6494](https://github.com/ClickHouse/ClickHouse/pull/6494) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Added a test for bad URIs. [#6493](https://github.com/ClickHouse/ClickHouse/pull/6493) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added more checks to `CAST` function. This should get more information about segmentation fault in fuzzy test. [#6346](https://github.com/ClickHouse/ClickHouse/pull/6346) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Added `gcc-9` support to `docker/builder` container that builds image locally. [#6333](https://github.com/ClickHouse/ClickHouse/pull/6333) ([Gleb Novikov](https://github.com/NanoBjorn))
+-   Test for primary key with `LowCardinality(String)`. [#5044](https://github.com/ClickHouse/ClickHouse/issues/5044) [#6219](https://github.com/ClickHouse/ClickHouse/pull/6219) ([dimarub2000](https://github.com/dimarub2000))
+-   Fixed tests affected by slow stack traces printing. [#6315](https://github.com/ClickHouse/ClickHouse/pull/6315) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add a test case for crash in `groupUniqArray` fixed in [#6029](https://github.com/ClickHouse/ClickHouse/pull/6029). [#4402](https://github.com/ClickHouse/ClickHouse/issues/4402) [#6129](https://github.com/ClickHouse/ClickHouse/pull/6129) ([akuzm](https://github.com/akuzm))
+-   Fixed indices mutations tests. [#6645](https://github.com/ClickHouse/ClickHouse/pull/6645) ([Nikita Vasilev](https://github.com/nikvas0))
+-   In performance test, do not read query log for queries we didn’t run. [#6427](https://github.com/ClickHouse/ClickHouse/pull/6427) ([akuzm](https://github.com/akuzm))
+-   Materialized view now could be created with any low cardinality types regardless to the setting about suspicious low cardinality types. [#6428](https://github.com/ClickHouse/ClickHouse/pull/6428) ([Olga Khvostikova](https://github.com/stavrolia))
+-   Updated tests for `send_logs_level` setting. [#6207](https://github.com/ClickHouse/ClickHouse/pull/6207) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix build under gcc-8.2. [#6196](https://github.com/ClickHouse/ClickHouse/pull/6196) ([Max Akhmedov](https://github.com/zlobober))
+-   Fix build with internal libc++. [#6724](https://github.com/ClickHouse/ClickHouse/pull/6724) ([Ivan](https://github.com/abyss7))
+-   Fix shared build with `rdkafka` library [#6101](https://github.com/ClickHouse/ClickHouse/pull/6101) ([Ivan](https://github.com/abyss7))
+-   Fixes for Mac OS build (incomplete). [#6390](https://github.com/ClickHouse/ClickHouse/pull/6390) ([alexey-milovidov](https://github.com/alexey-milovidov)) [#6429](https://github.com/ClickHouse/ClickHouse/pull/6429) ([alex-zaitsev](https://github.com/alex-zaitsev))
+-   Fix “splitted” build. [#6618](https://github.com/ClickHouse/ClickHouse/pull/6618) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Other build fixes: [#6186](https://github.com/ClickHouse/ClickHouse/pull/6186) ([Amos Bird](https://github.com/amosbird)) [#6486](https://github.com/ClickHouse/ClickHouse/pull/6486) [#6348](https://github.com/ClickHouse/ClickHouse/pull/6348) ([vxider](https://github.com/Vxider)) [#6744](https://github.com/ClickHouse/ClickHouse/pull/6744) ([Ivan](https://github.com/abyss7)) [#6016](https://github.com/ClickHouse/ClickHouse/pull/6016) [#6421](https://github.com/ClickHouse/ClickHouse/pull/6421) [#6491](https://github.com/ClickHouse/ClickHouse/pull/6491) ([proller](https://github.com/proller))
+
+#### Backward Incompatible Change {#backward-incompatible-change-3}
+
+-   Removed rarely used table function `catBoostPool` and storage `CatBoostPool`. If you have used this table function, please write email to `clickhouse-feedback@yandex-team.com`. Note that CatBoost integration remains and will be supported. [#6279](https://github.com/ClickHouse/ClickHouse/pull/6279) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Disable `ANY RIGHT JOIN` and `ANY FULL JOIN` by default. Set `any_join_distinct_right_table_keys` setting to enable them. [#5126](https://github.com/ClickHouse/ClickHouse/issues/5126) [#6351](https://github.com/ClickHouse/ClickHouse/pull/6351) ([Artem Zuikov](https://github.com/4ertus2))
+
+## ClickHouse Release 19.13 {#clickhouse-release-19-13}
+
+### ClickHouse Release 19.13.6.51, 2019-10-02 {#clickhouse-release-19-13-6-51-2019-10-02}
+
+#### Bug Fix {#bug-fix-9}
+
+-   This release also contains all bug fixes from 19.11.12.69.
+
+### ClickHouse Release 19.13.5.44, 2019-09-20 {#clickhouse-release-19-13-5-44-2019-09-20}
+
+#### Bug Fix {#bug-fix-10}
+
+-   This release also contains all bug fixes from 19.14.6.12.
+-   Fixed possible inconsistent state of table while executing `DROP` query for replicated table while zookeeper is not accessible. [#6045](https://github.com/ClickHouse/ClickHouse/issues/6045) [#6413](https://github.com/ClickHouse/ClickHouse/pull/6413) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+-   Fix for data race in StorageMerge [#6717](https://github.com/ClickHouse/ClickHouse/pull/6717) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix bug introduced in query profiler which leads to endless recv from socket. [#6386](https://github.com/ClickHouse/ClickHouse/pull/6386) ([alesapin](https://github.com/alesapin))
+-   Fix excessive CPU usage while executing `JSONExtractRaw` function over a boolean value. [#6208](https://github.com/ClickHouse/ClickHouse/pull/6208) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fixes the regression while pushing to materialized view. [#6415](https://github.com/ClickHouse/ClickHouse/pull/6415) ([Ivan](https://github.com/abyss7))
+-   Table function `url` had the vulnerability allowed the attacker to inject arbitrary HTTP headers in the request. This issue was found by [Nikita Tikhomirov](https://github.com/NSTikhomirov). [#6466](https://github.com/ClickHouse/ClickHouse/pull/6466) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix useless `AST` check in Set index. [#6510](https://github.com/ClickHouse/ClickHouse/issues/6510) [#6651](https://github.com/ClickHouse/ClickHouse/pull/6651) ([Nikita Vasilev](https://github.com/nikvas0))
+-   Fixed parsing of `AggregateFunction` values embedded in query. [#6575](https://github.com/ClickHouse/ClickHouse/issues/6575) [#6773](https://github.com/ClickHouse/ClickHouse/pull/6773) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Fixed wrong behaviour of `trim` functions family. [#6647](https://github.com/ClickHouse/ClickHouse/pull/6647) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.13.4.32, 2019-09-10 {#clickhouse-release-19-13-4-32-2019-09-10}
+
+#### Bug Fix {#bug-fix-11}
+
+-   This release also contains all bug security fixes from 19.11.9.52 and 19.11.10.54.
+-   Fixed data race in `system.parts` table and `ALTER` query. [#6245](https://github.com/ClickHouse/ClickHouse/issues/6245) [#6513](https://github.com/ClickHouse/ClickHouse/pull/6513) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed mismatched header in streams happened in case of reading from empty distributed table with sample and prewhere. [#6167](https://github.com/ClickHouse/ClickHouse/issues/6167) ([Lixiang Qian](https://github.com/fancyqlx)) [#6823](https://github.com/ClickHouse/ClickHouse/pull/6823) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fixed crash when using `IN` clause with a subquery with a tuple. [#6125](https://github.com/ClickHouse/ClickHouse/issues/6125) [#6550](https://github.com/ClickHouse/ClickHouse/pull/6550) ([tavplubix](https://github.com/tavplubix))
+-   Fix case with same column names in `GLOBAL JOIN ON` section. [#6181](https://github.com/ClickHouse/ClickHouse/pull/6181) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix crash when casting types to `Decimal` that do not support it. Throw exception instead. [#6297](https://github.com/ClickHouse/ClickHouse/pull/6297) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed crash in `extractAll()` function. [#6644](https://github.com/ClickHouse/ClickHouse/pull/6644) ([Artem Zuikov](https://github.com/4ertus2))
+-   Query transformation for `MySQL`, `ODBC`, `JDBC` table functions now works properly for `SELECT WHERE` queries with multiple `AND` expressions. [#6381](https://github.com/ClickHouse/ClickHouse/issues/6381) [#6676](https://github.com/ClickHouse/ClickHouse/pull/6676) ([dimarub2000](https://github.com/dimarub2000))
+-   Added previous declaration checks for MySQL 8 integration. [#6569](https://github.com/ClickHouse/ClickHouse/pull/6569) ([Rafael David Tinoco](https://github.com/rafaeldtinoco))
+
+#### Security Fix {#security-fix-1}
+
+-   Fix two vulnerabilities in codecs in decompression phase (malicious user can fabricate compressed data that will lead to buffer overflow in decompression). [#6670](https://github.com/ClickHouse/ClickHouse/pull/6670) ([Artem Zuikov](https://github.com/4ertus2))
+
+### ClickHouse Release 19.13.3.26, 2019-08-22 {#clickhouse-release-19-13-3-26-2019-08-22}
+
+#### Bug Fix {#bug-fix-12}
+
+-   Fix `ALTER TABLE ... UPDATE` query for tables with `enable_mixed_granularity_parts=1`. [#6543](https://github.com/ClickHouse/ClickHouse/pull/6543) ([alesapin](https://github.com/alesapin))
+-   Fix NPE when using IN clause with a subquery with a tuple. [#6125](https://github.com/ClickHouse/ClickHouse/issues/6125) [#6550](https://github.com/ClickHouse/ClickHouse/pull/6550) ([tavplubix](https://github.com/tavplubix))
+-   Fixed an issue that if a stale replica becomes alive, it may still have data parts that were removed by DROP PARTITION. [#6522](https://github.com/ClickHouse/ClickHouse/issues/6522) [#6523](https://github.com/ClickHouse/ClickHouse/pull/6523) ([tavplubix](https://github.com/tavplubix))
+-   Fixed issue with parsing CSV [#6426](https://github.com/ClickHouse/ClickHouse/issues/6426) [#6559](https://github.com/ClickHouse/ClickHouse/pull/6559) ([tavplubix](https://github.com/tavplubix))
+-   Fixed data race in system.parts table and ALTER query. This fixes [#6245](https://github.com/ClickHouse/ClickHouse/issues/6245). [#6513](https://github.com/ClickHouse/ClickHouse/pull/6513) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed wrong code in mutations that may lead to memory corruption. Fixed segfault with read of address `0x14c0` that may happed due to concurrent `DROP TABLE` and `SELECT` from `system.parts` or `system.parts_columns`. Fixed race condition in preparation of mutation queries. Fixed deadlock caused by `OPTIMIZE` of Replicated tables and concurrent modification operations like ALTERs. [#6514](https://github.com/ClickHouse/ClickHouse/pull/6514) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed possible data loss after `ALTER DELETE` query on table with skipping index. [#6224](https://github.com/ClickHouse/ClickHouse/issues/6224) [#6282](https://github.com/ClickHouse/ClickHouse/pull/6282) ([Nikita Vasilev](https://github.com/nikvas0))
+
+#### Security Fix {#security-fix-2}
+
+-   If the attacker has write access to ZooKeeper and is able to run custom server available from the network where ClickHouse run, it can create custom-built malicious server that will act as ClickHouse replica and register it in ZooKeeper. When another replica will fetch data part from malicious replica, it can force clickhouse-server to write to arbitrary path on filesystem. Found by Eldar Zaitov, information security team at Yandex. [#6247](https://github.com/ClickHouse/ClickHouse/pull/6247) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.13.2.19, 2019-08-14 {#clickhouse-release-19-13-2-19-2019-08-14}
+
+#### New Feature {#new-feature-5}
+
+-   Sampling profiler on query level. [Example](https://gist.github.com/alexey-milovidov/92758583dd41c24c360fdb8d6a4da194). [#4247](https://github.com/ClickHouse/ClickHouse/issues/4247) ([laplab](https://github.com/laplab)) [#6124](https://github.com/ClickHouse/ClickHouse/pull/6124) ([alexey-milovidov](https://github.com/alexey-milovidov)) [#6250](https://github.com/ClickHouse/ClickHouse/pull/6250) [#6283](https://github.com/ClickHouse/ClickHouse/pull/6283) [#6386](https://github.com/ClickHouse/ClickHouse/pull/6386)
+-   Allow to specify a list of columns with `COLUMNS('regexp')` expression that works like a more sophisticated variant of `*` asterisk. [#5951](https://github.com/ClickHouse/ClickHouse/pull/5951) ([mfridental](https://github.com/mfridental)), ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   `CREATE TABLE AS table_function()` is now possible [#6057](https://github.com/ClickHouse/ClickHouse/pull/6057) ([dimarub2000](https://github.com/dimarub2000))
+-   Adam optimizer for stochastic gradient descent is used by default in `stochasticLinearRegression()` and `stochasticLogisticRegression()` aggregate functions, because it shows good quality without almost any tuning. [#6000](https://github.com/ClickHouse/ClickHouse/pull/6000) ([Quid37](https://github.com/Quid37))
+-   Added functions for working with the сustom week number [#5212](https://github.com/ClickHouse/ClickHouse/pull/5212) ([Andy Yang](https://github.com/andyyzh))
+-   `RENAME` queries now work with all storages. [#5953](https://github.com/ClickHouse/ClickHouse/pull/5953) ([Ivan](https://github.com/abyss7))
+-   Now client receive logs from server with any desired level by setting `send_logs_level` regardless to the log level specified in server settings. [#5964](https://github.com/ClickHouse/ClickHouse/pull/5964) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+
+#### Backward Incompatible Change {#backward-incompatible-change-4}
+
+-   The setting `input_format_defaults_for_omitted_fields` is enabled by default. Inserts in Distributed tables need this setting to be the same on cluster (you need to set it before rolling update). It enables calculation of complex default expressions for omitted fields in `JSONEachRow` and `CSV*` formats. It should be the expected behavior but may lead to negligible performance difference. [#6043](https://github.com/ClickHouse/ClickHouse/pull/6043) ([Artem Zuikov](https://github.com/4ertus2)), [#5625](https://github.com/ClickHouse/ClickHouse/pull/5625) ([akuzm](https://github.com/akuzm))
+
+#### Experimental Features {#experimental-features}
+
+-   New query processing pipeline. Use `experimental_use_processors=1` option to enable it. Use for your own trouble. [#4914](https://github.com/ClickHouse/ClickHouse/pull/4914) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+
+#### Bug Fix {#bug-fix-13}
+
+-   Kafka integration has been fixed in this version.
+-   Fixed `DoubleDelta` encoding of `Int64` for large `DoubleDelta` values, improved `DoubleDelta` encoding for random data for `Int32`. [#5998](https://github.com/ClickHouse/ClickHouse/pull/5998) ([Vasily Nemkov](https://github.com/Enmk))
+-   Fixed overestimation of `max_rows_to_read` if the setting `merge_tree_uniform_read_distribution` is set to 0. [#6019](https://github.com/ClickHouse/ClickHouse/pull/6019) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Improvement {#improvement-4}
+
+-   Throws an exception if `config.d` file does not have the corresponding root element as the config file [#6123](https://github.com/ClickHouse/ClickHouse/pull/6123) ([dimarub2000](https://github.com/dimarub2000))
+
+#### Performance Improvement {#performance-improvement-3}
+
+-   Optimize `count()`. Now it uses the smallest column (if possible). [#6028](https://github.com/ClickHouse/ClickHouse/pull/6028) ([Amos Bird](https://github.com/amosbird))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-5}
+
+-   Report memory usage in performance tests. [#5899](https://github.com/ClickHouse/ClickHouse/pull/5899) ([akuzm](https://github.com/akuzm))
+-   Fix build with external `libcxx` [#6010](https://github.com/ClickHouse/ClickHouse/pull/6010) ([Ivan](https://github.com/abyss7))
+-   Fix shared build with `rdkafka` library [#6101](https://github.com/ClickHouse/ClickHouse/pull/6101) ([Ivan](https://github.com/abyss7))
+
+## ClickHouse Release 19.11 {#clickhouse-release-19-11}
+
+### ClickHouse Release 19.11.13.74, 2019-11-01 {#clickhouse-release-19-11-13-74-2019-11-01}
+
+#### Bug Fix {#bug-fix-14}
+
+-   Fixed rare crash in `ALTER MODIFY COLUMN` and vertical merge when one of merged/altered parts is empty (0 rows). [#6780](https://github.com/ClickHouse/ClickHouse/pull/6780) ([alesapin](https://github.com/alesapin))
+-   Manual update of `SIMDJSON`. This fixes possible flooding of stderr files with bogus json diagnostic messages. [#7548](https://github.com/ClickHouse/ClickHouse/pull/7548) ([Alexander Kazakov](https://github.com/Akazz))
+-   Fixed bug with `mrk` file extension for mutations ([alesapin](https://github.com/alesapin))
+
+### ClickHouse Release 19.11.12.69, 2019-10-02 {#clickhouse-release-19-11-12-69-2019-10-02}
+
+#### Bug Fix {#bug-fix-15}
+
+-   Fixed performance degradation of index analysis on complex keys on large tables. This fixes [#6924](https://github.com/ClickHouse/ClickHouse/issues/6924). [#7075](https://github.com/ClickHouse/ClickHouse/pull/7075) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Avoid rare SIGSEGV while sending data in tables with Distributed engine (`Failed to send batch: file with index XXXXX is absent`). [#7032](https://github.com/ClickHouse/ClickHouse/pull/7032) ([Azat Khuzhin](https://github.com/azat))
+-   Fix `Unknown identifier` with multiple joins. This fixes [#5254](https://github.com/ClickHouse/ClickHouse/issues/5254). [#7022](https://github.com/ClickHouse/ClickHouse/pull/7022) ([Artem Zuikov](https://github.com/4ertus2))
+
+### ClickHouse Release 19.11.11.57, 2019-09-13 {#clickhouse-release-19-11-11-57-2019-09-13}
+
+-   Fix logical error causing segfaults when selecting from Kafka empty topic. [#6902](https://github.com/ClickHouse/ClickHouse/issues/6902) [#6909](https://github.com/ClickHouse/ClickHouse/pull/6909) ([Ivan](https://github.com/abyss7))
+-   Fix for function `АrrayEnumerateUniqRanked` with empty arrays in params. [#6928](https://github.com/ClickHouse/ClickHouse/pull/6928) ([proller](https://github.com/proller))
+
+### ClickHouse Release 19.11.10.54, 2019-09-10 {#clickhouse-release-19-11-10-54-2019-09-10}
+
+#### Bug Fix {#bug-fix-16}
+
+-   Do store offsets for Kafka messages manually to be able to commit them all at once for all partitions. Fixes potential duplication in “one consumer - many partitions” scenario. [#6872](https://github.com/ClickHouse/ClickHouse/pull/6872) ([Ivan](https://github.com/abyss7))
+
+### ClickHouse Release 19.11.9.52, 2019-09-6 {#clickhouse-release-19-11-9-52-2019-09-6}
+
+-   Improve error handling in cache dictionaries. [#6737](https://github.com/ClickHouse/ClickHouse/pull/6737) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fixed bug in function `arrayEnumerateUniqRanked`. [#6779](https://github.com/ClickHouse/ClickHouse/pull/6779) ([proller](https://github.com/proller))
+-   Fix `JSONExtract` function while extracting a `Tuple` from JSON. [#6718](https://github.com/ClickHouse/ClickHouse/pull/6718) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fixed possible data loss after `ALTER DELETE` query on table with skipping index. [#6224](https://github.com/ClickHouse/ClickHouse/issues/6224) [#6282](https://github.com/ClickHouse/ClickHouse/pull/6282) ([Nikita Vasilev](https://github.com/nikvas0))
+-   Fixed performance test. [#6392](https://github.com/ClickHouse/ClickHouse/pull/6392) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Parquet: Fix reading boolean columns. [#6579](https://github.com/ClickHouse/ClickHouse/pull/6579) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed wrong behaviour of `nullIf` function for constant arguments. [#6518](https://github.com/ClickHouse/ClickHouse/pull/6518) ([Guillaume Tassery](https://github.com/YiuRULE)) [#6580](https://github.com/ClickHouse/ClickHouse/pull/6580) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix Kafka messages duplication problem on normal server restart. [#6597](https://github.com/ClickHouse/ClickHouse/pull/6597) ([Ivan](https://github.com/abyss7))
+-   Fixed an issue when long `ALTER UPDATE` or `ALTER DELETE` may prevent regular merges to run. Prevent mutations from executing if there is no enough free threads available. [#6502](https://github.com/ClickHouse/ClickHouse/issues/6502) [#6617](https://github.com/ClickHouse/ClickHouse/pull/6617) ([tavplubix](https://github.com/tavplubix))
+-   Fixed error with processing “timezone” in server configuration file. [#6709](https://github.com/ClickHouse/ClickHouse/pull/6709) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix kafka tests. [#6805](https://github.com/ClickHouse/ClickHouse/pull/6805) ([Ivan](https://github.com/abyss7))
+
+#### Security Fix {#security-fix-3}
+
+-   If the attacker has write access to ZooKeeper and is able to run custom server available from the network where ClickHouse runs, it can create custom-built malicious server that will act as ClickHouse replica and register it in ZooKeeper. When another replica will fetch data part from malicious replica, it can force clickhouse-server to write to arbitrary path on filesystem. Found by Eldar Zaitov, information security team at Yandex. [#6247](https://github.com/ClickHouse/ClickHouse/pull/6247) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.11.8.46, 2019-08-22 {#clickhouse-release-19-11-8-46-2019-08-22}
+
+#### Bug Fix {#bug-fix-17}
+
+-   Fix `ALTER TABLE ... UPDATE` query for tables with `enable_mixed_granularity_parts=1`. [#6543](https://github.com/ClickHouse/ClickHouse/pull/6543) ([alesapin](https://github.com/alesapin))
+-   Fix NPE when using IN clause with a subquery with a tuple. [#6125](https://github.com/ClickHouse/ClickHouse/issues/6125) [#6550](https://github.com/ClickHouse/ClickHouse/pull/6550) ([tavplubix](https://github.com/tavplubix))
+-   Fixed an issue that if a stale replica becomes alive, it may still have data parts that were removed by DROP PARTITION. [#6522](https://github.com/ClickHouse/ClickHouse/issues/6522) [#6523](https://github.com/ClickHouse/ClickHouse/pull/6523) ([tavplubix](https://github.com/tavplubix))
+-   Fixed issue with parsing CSV [#6426](https://github.com/ClickHouse/ClickHouse/issues/6426) [#6559](https://github.com/ClickHouse/ClickHouse/pull/6559) ([tavplubix](https://github.com/tavplubix))
+-   Fixed data race in system.parts table and ALTER query. This fixes [#6245](https://github.com/ClickHouse/ClickHouse/issues/6245). [#6513](https://github.com/ClickHouse/ClickHouse/pull/6513) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed wrong code in mutations that may lead to memory corruption. Fixed segfault with read of address `0x14c0` that may happed due to concurrent `DROP TABLE` and `SELECT` from `system.parts` or `system.parts_columns`. Fixed race condition in preparation of mutation queries. Fixed deadlock caused by `OPTIMIZE` of Replicated tables and concurrent modification operations like ALTERs. [#6514](https://github.com/ClickHouse/ClickHouse/pull/6514) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.11.7.40, 2019-08-14 {#clickhouse-release-19-11-7-40-2019-08-14}
+
+#### Bug Fix {#bug-fix-18}
+
+-   Kafka integration has been fixed in this version.
+-   Fix segfault when using `arrayReduce` for constant arguments. [#6326](https://github.com/ClickHouse/ClickHouse/pull/6326) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed `toFloat()` monotonicity. [#6374](https://github.com/ClickHouse/ClickHouse/pull/6374) ([dimarub2000](https://github.com/dimarub2000))
+-   Fix segfault with enabled `optimize_skip_unused_shards` and missing sharding key. [#6384](https://github.com/ClickHouse/ClickHouse/pull/6384) ([CurtizJ](https://github.com/CurtizJ))
+-   Fixed logic of `arrayEnumerateUniqRanked` function. [#6423](https://github.com/ClickHouse/ClickHouse/pull/6423) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Removed extra verbose logging from MySQL handler. [#6389](https://github.com/ClickHouse/ClickHouse/pull/6389) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix wrong behavior and possible segfaults in `topK` and `topKWeighted` aggregated functions. [#6404](https://github.com/ClickHouse/ClickHouse/pull/6404) ([CurtizJ](https://github.com/CurtizJ))
+-   Do not expose virtual columns in `system.columns` table. This is required for backward compatibility. [#6406](https://github.com/ClickHouse/ClickHouse/pull/6406) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix bug with memory allocation for string fields in complex key cache dictionary. [#6447](https://github.com/ClickHouse/ClickHouse/pull/6447) ([alesapin](https://github.com/alesapin))
+-   Fix bug with enabling adaptive granularity when creating new replica for `Replicated*MergeTree` table. [#6452](https://github.com/ClickHouse/ClickHouse/pull/6452) ([alesapin](https://github.com/alesapin))
+-   Fix infinite loop when reading Kafka messages. [#6354](https://github.com/ClickHouse/ClickHouse/pull/6354) ([abyss7](https://github.com/abyss7))
+-   Fixed the possibility of a fabricated query to cause server crash due to stack overflow in SQL parser and possibility of stack overflow in `Merge` and `Distributed` tables [#6433](https://github.com/ClickHouse/ClickHouse/pull/6433) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed Gorilla encoding error on small sequences. [#6444](https://github.com/ClickHouse/ClickHouse/pull/6444) ([Enmk](https://github.com/Enmk))
+
+#### Improvement {#improvement-5}
+
+-   Allow user to override `poll_interval` and `idle_connection_timeout` settings on connection. [#6230](https://github.com/ClickHouse/ClickHouse/pull/6230) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.11.5.28, 2019-08-05 {#clickhouse-release-19-11-5-28-2019-08-05}
+
+#### Bug Fix {#bug-fix-19}
+
+-   Fixed the possibility of hanging queries when server is overloaded. [#6301](https://github.com/ClickHouse/ClickHouse/pull/6301) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix FPE in yandexConsistentHash function. This fixes [#6304](https://github.com/ClickHouse/ClickHouse/issues/6304). [#6126](https://github.com/ClickHouse/ClickHouse/pull/6126) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed bug in conversion of `LowCardinality` types in `AggregateFunctionFactory`. This fixes [#6257](https://github.com/ClickHouse/ClickHouse/issues/6257). [#6281](https://github.com/ClickHouse/ClickHouse/pull/6281) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix parsing of `bool` settings from `true` and `false` strings in configuration files. [#6278](https://github.com/ClickHouse/ClickHouse/pull/6278) ([alesapin](https://github.com/alesapin))
+-   Fix rare bug with incompatible stream headers in queries to `Distributed` table over `MergeTree` table when part of `WHERE` moves to `PREWHERE`. [#6236](https://github.com/ClickHouse/ClickHouse/pull/6236) ([alesapin](https://github.com/alesapin))
+-   Fixed overflow in integer division of signed type to unsigned type. This fixes [#6214](https://github.com/ClickHouse/ClickHouse/issues/6214). [#6233](https://github.com/ClickHouse/ClickHouse/pull/6233) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Backward Incompatible Change {#backward-incompatible-change-5}
+
+-   `Kafka` still broken.
+
+### ClickHouse Release 19.11.4.24, 2019-08-01 {#clickhouse-release-19-11-4-24-2019-08-01}
+
+#### Bug Fix {#bug-fix-20}
+
+-   Fix bug with writing secondary indices marks with adaptive granularity. [#6126](https://github.com/ClickHouse/ClickHouse/pull/6126) ([alesapin](https://github.com/alesapin))
+-   Fix `WITH ROLLUP` and `WITH CUBE` modifiers of `GROUP BY` with two-level aggregation. [#6225](https://github.com/ClickHouse/ClickHouse/pull/6225) ([Anton Popov](https://github.com/CurtizJ))
+-   Fixed hang in `JSONExtractRaw` function. Fixed [#6195](https://github.com/ClickHouse/ClickHouse/issues/6195) [#6198](https://github.com/ClickHouse/ClickHouse/pull/6198) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix segfault in ExternalLoader::reloadOutdated(). [#6082](https://github.com/ClickHouse/ClickHouse/pull/6082) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fixed the case when server may close listening sockets but not shutdown and continue serving remaining queries. You may end up with two running clickhouse-server processes. Sometimes, the server may return an error `bad_function_call` for remaining queries. [#6231](https://github.com/ClickHouse/ClickHouse/pull/6231) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed useless and incorrect condition on update field for initial loading of external dictionaries via ODBC, MySQL, ClickHouse and HTTP. This fixes [#6069](https://github.com/ClickHouse/ClickHouse/issues/6069) [#6083](https://github.com/ClickHouse/ClickHouse/pull/6083) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed irrelevant exception in cast of `LowCardinality(Nullable)` to not-Nullable column in case if it does not contain Nulls (e.g. in query like `SELECT CAST(CAST('Hello' AS LowCardinality(Nullable(String))) AS String)`. [#6094](https://github.com/ClickHouse/ClickHouse/issues/6094) [#6119](https://github.com/ClickHouse/ClickHouse/pull/6119) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix non-deterministic result of “uniq” aggregate function in extreme rare cases. The bug was present in all ClickHouse versions. [#6058](https://github.com/ClickHouse/ClickHouse/pull/6058) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Segfault when we set a little bit too high CIDR on the function `IPv6CIDRToRange`. [#6068](https://github.com/ClickHouse/ClickHouse/pull/6068) ([Guillaume Tassery](https://github.com/YiuRULE))
+-   Fixed small memory leak when server throw many exceptions from many different contexts. [#6144](https://github.com/ClickHouse/ClickHouse/pull/6144) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix the situation when consumer got paused before subscription and not resumed afterwards. [#6075](https://github.com/ClickHouse/ClickHouse/pull/6075) ([Ivan](https://github.com/abyss7)) Note that Kafka is broken in this version.
+-   Clearing the Kafka data buffer from the previous read operation that was completed with an error [#6026](https://github.com/ClickHouse/ClickHouse/pull/6026) ([Nikolay](https://github.com/bopohaa)) Note that Kafka is broken in this version.
+-   Since `StorageMergeTree::background_task_handle` is initialized in `startup()` the `MergeTreeBlockOutputStream::write()` may try to use it before initialization. Just check if it is initialized. [#6080](https://github.com/ClickHouse/ClickHouse/pull/6080) ([Ivan](https://github.com/abyss7))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-6}
+
+-   Added official `rpm` packages. [#5740](https://github.com/ClickHouse/ClickHouse/pull/5740) ([proller](https://github.com/proller)) ([alesapin](https://github.com/alesapin))
+-   Add an ability to build `.rpm` and `.tgz` packages with `packager` script. [#5769](https://github.com/ClickHouse/ClickHouse/pull/5769) ([alesapin](https://github.com/alesapin))
+-   Fixes for “Arcadia” build system. [#6223](https://github.com/ClickHouse/ClickHouse/pull/6223) ([proller](https://github.com/proller))
+
+#### Backward Incompatible Change {#backward-incompatible-change-6}
+
+-   `Kafka` is broken in this version.
+
+### ClickHouse Release 19.11.3.11, 2019-07-18 {#clickhouse-release-19-11-3-11-2019-07-18}
+
+#### New Feature {#new-feature-6}
+
+-   Added support for prepared statements. [#5331](https://github.com/ClickHouse/ClickHouse/pull/5331/) ([Alexander](https://github.com/sanych73)) [#5630](https://github.com/ClickHouse/ClickHouse/pull/5630) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   `DoubleDelta` and `Gorilla` column codecs [#5600](https://github.com/ClickHouse/ClickHouse/pull/5600) ([Vasily Nemkov](https://github.com/Enmk))
+-   Added `os_thread_priority` setting that allows to control the “nice” value of query processing threads that is used by OS to adjust dynamic scheduling priority. It requires `CAP_SYS_NICE` capabilities to work. This implements [#5858](https://github.com/ClickHouse/ClickHouse/issues/5858) [#5909](https://github.com/ClickHouse/ClickHouse/pull/5909) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Implement `_topic`, `_offset`, `_key` columns for Kafka engine [#5382](https://github.com/ClickHouse/ClickHouse/pull/5382) ([Ivan](https://github.com/abyss7)) Note that Kafka is broken in this version.
+-   Add aggregate function combinator `-Resample` [#5590](https://github.com/ClickHouse/ClickHouse/pull/5590) ([hcz](https://github.com/hczhcz))
+-   Aggregate functions `groupArrayMovingSum(win_size)(x)` and `groupArrayMovingAvg(win_size)(x)`, which calculate moving sum/avg with or without window-size limitation. [#5595](https://github.com/ClickHouse/ClickHouse/pull/5595) ([inv2004](https://github.com/inv2004))
+-   Add synonim `arrayFlatten` \<-\> `flatten` [#5764](https://github.com/ClickHouse/ClickHouse/pull/5764) ([hcz](https://github.com/hczhcz))
+-   Intergate H3 function `geoToH3` from Uber. [#4724](https://github.com/ClickHouse/ClickHouse/pull/4724) ([Remen Ivan](https://github.com/BHYCHIK)) [#5805](https://github.com/ClickHouse/ClickHouse/pull/5805) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Bug Fix {#bug-fix-21}
+
+-   Implement DNS cache with asynchronous update. Separate thread resolves all hosts and updates DNS cache with period (setting `dns_cache_update_period`). It should help, when ip of hosts changes frequently. [#5857](https://github.com/ClickHouse/ClickHouse/pull/5857) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix segfault in `Delta` codec which affects columns with values less than 32 bits size. The bug led to random memory corruption. [#5786](https://github.com/ClickHouse/ClickHouse/pull/5786) ([alesapin](https://github.com/alesapin))
+-   Fix segfault in TTL merge with non-physical columns in block. [#5819](https://github.com/ClickHouse/ClickHouse/pull/5819) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix rare bug in checking of part with `LowCardinality` column. Previously `checkDataPart` always fails for part with `LowCardinality` column. [#5832](https://github.com/ClickHouse/ClickHouse/pull/5832) ([alesapin](https://github.com/alesapin))
+-   Avoid hanging connections when server thread pool is full. It is important for connections from `remote` table function or connections to a shard without replicas when there is long connection timeout. This fixes [#5878](https://github.com/ClickHouse/ClickHouse/issues/5878) [#5881](https://github.com/ClickHouse/ClickHouse/pull/5881) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Support for constant arguments to `evalMLModel` function. This fixes [#5817](https://github.com/ClickHouse/ClickHouse/issues/5817) [#5820](https://github.com/ClickHouse/ClickHouse/pull/5820) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed the issue when ClickHouse determines default time zone as `UCT` instead of `UTC`. This fixes [#5804](https://github.com/ClickHouse/ClickHouse/issues/5804). [#5828](https://github.com/ClickHouse/ClickHouse/pull/5828) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed buffer underflow in `visitParamExtractRaw`. This fixes [#5901](https://github.com/ClickHouse/ClickHouse/issues/5901) [#5902](https://github.com/ClickHouse/ClickHouse/pull/5902) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Now distributed `DROP/ALTER/TRUNCATE/OPTIMIZE ON CLUSTER` queries will be executed directly on leader replica. [#5757](https://github.com/ClickHouse/ClickHouse/pull/5757) ([alesapin](https://github.com/alesapin))
+-   Fix `coalesce` for `ColumnConst` with `ColumnNullable` + related changes. [#5755](https://github.com/ClickHouse/ClickHouse/pull/5755) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix the `ReadBufferFromKafkaConsumer` so that it keeps reading new messages after `commit()` even if it was stalled before [#5852](https://github.com/ClickHouse/ClickHouse/pull/5852) ([Ivan](https://github.com/abyss7))
+-   Fix `FULL` and `RIGHT` JOIN results when joining on `Nullable` keys in right table. [#5859](https://github.com/ClickHouse/ClickHouse/pull/5859) ([Artem Zuikov](https://github.com/4ertus2))
+-   Possible fix of infinite sleeping of low-priority queries. [#5842](https://github.com/ClickHouse/ClickHouse/pull/5842) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix race condition, which cause that some queries may not appear in query_log after `SYSTEM FLUSH LOGS` query. [#5456](https://github.com/ClickHouse/ClickHouse/issues/5456) [#5685](https://github.com/ClickHouse/ClickHouse/pull/5685) ([Anton Popov](https://github.com/CurtizJ))
+-   Fixed `heap-use-after-free` ASan warning in ClusterCopier caused by watch which try to use already removed copier object. [#5871](https://github.com/ClickHouse/ClickHouse/pull/5871) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fixed wrong `StringRef` pointer returned by some implementations of `IColumn::deserializeAndInsertFromArena`. This bug affected only unit-tests. [#5973](https://github.com/ClickHouse/ClickHouse/pull/5973) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Prevent source and intermediate array join columns of masking same name columns. [#5941](https://github.com/ClickHouse/ClickHouse/pull/5941) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix insert and select query to MySQL engine with MySQL style identifier quoting. [#5704](https://github.com/ClickHouse/ClickHouse/pull/5704) ([Winter Zhang](https://github.com/zhang2014))
+-   Now `CHECK TABLE` query can work with MergeTree engine family. It returns check status and message if any for each part (or file in case of simplier engines). Also, fix bug in fetch of a broken part. [#5865](https://github.com/ClickHouse/ClickHouse/pull/5865) ([alesapin](https://github.com/alesapin))
+-   Fix SPLIT_SHARED_LIBRARIES runtime [#5793](https://github.com/ClickHouse/ClickHouse/pull/5793) ([Danila Kutenin](https://github.com/danlark1))
+-   Fixed time zone initialization when `/etc/localtime` is a relative symlink like `../usr/share/zoneinfo/Asia/Istanbul` [#5922](https://github.com/ClickHouse/ClickHouse/pull/5922) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   clickhouse-copier: Fix use-after free on shutdown [#5752](https://github.com/ClickHouse/ClickHouse/pull/5752) ([proller](https://github.com/proller))
+-   Updated `simdjson`. Fixed the issue that some invalid JSONs with zero bytes successfully parse. [#5938](https://github.com/ClickHouse/ClickHouse/pull/5938) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix shutdown of SystemLogs [#5802](https://github.com/ClickHouse/ClickHouse/pull/5802) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix hanging when condition in invalidate_query depends on a dictionary. [#6011](https://github.com/ClickHouse/ClickHouse/pull/6011) ([Vitaly Baranov](https://github.com/vitlibar))
+
+#### Improvement {#improvement-6}
+
+-   Allow unresolvable addresses in cluster configuration. They will be considered unavailable and tried to resolve at every connection attempt. This is especially useful for Kubernetes. This fixes [#5714](https://github.com/ClickHouse/ClickHouse/issues/5714) [#5924](https://github.com/ClickHouse/ClickHouse/pull/5924) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Close idle TCP connections (with one hour timeout by default). This is especially important for large clusters with multiple distributed tables on every server, because every server can possibly keep a connection pool to every other server, and after peak query concurrency, connections will stall. This fixes [#5879](https://github.com/ClickHouse/ClickHouse/issues/5879) [#5880](https://github.com/ClickHouse/ClickHouse/pull/5880) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Better quality of `topK` function. Changed the SavingSpace set behavior to remove the last element if the new element have a bigger weight. [#5833](https://github.com/ClickHouse/ClickHouse/issues/5833) [#5850](https://github.com/ClickHouse/ClickHouse/pull/5850) ([Guillaume Tassery](https://github.com/YiuRULE))
+-   URL functions to work with domains now can work for incomplete URLs without scheme [#5725](https://github.com/ClickHouse/ClickHouse/pull/5725) ([alesapin](https://github.com/alesapin))
+-   Checksums added to the `system.parts_columns` table. [#5874](https://github.com/ClickHouse/ClickHouse/pull/5874) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+-   Added `Enum` data type as a synonim for `Enum8` or `Enum16`. [#5886](https://github.com/ClickHouse/ClickHouse/pull/5886) ([dimarub2000](https://github.com/dimarub2000))
+-   Full bit transpose variant for `T64` codec. Could lead to better compression with `zstd`. [#5742](https://github.com/ClickHouse/ClickHouse/pull/5742) ([Artem Zuikov](https://github.com/4ertus2))
+-   Condition on `startsWith` function now can uses primary key. This fixes [#5310](https://github.com/ClickHouse/ClickHouse/issues/5310) and [#5882](https://github.com/ClickHouse/ClickHouse/issues/5882) [#5919](https://github.com/ClickHouse/ClickHouse/pull/5919) ([dimarub2000](https://github.com/dimarub2000))
+-   Allow to use `clickhouse-copier` with cross-replication cluster topology by permitting empty database name. [#5745](https://github.com/ClickHouse/ClickHouse/pull/5745) ([nvartolomei](https://github.com/nvartolomei))
+-   Use `UTC` as default timezone on a system without `tzdata` (e.g. bare Docker container). Before this patch, error message `Could not determine local time zone` was printed and server or client refused to start. [#5827](https://github.com/ClickHouse/ClickHouse/pull/5827) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Returned back support for floating point argument in function `quantileTiming` for backward compatibility. [#5911](https://github.com/ClickHouse/ClickHouse/pull/5911) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Show which table is missing column in error messages. [#5768](https://github.com/ClickHouse/ClickHouse/pull/5768) ([Ivan](https://github.com/abyss7))
+-   Disallow run query with same query_id by various users [#5430](https://github.com/ClickHouse/ClickHouse/pull/5430) ([proller](https://github.com/proller))
+-   More robust code for sending metrics to Graphite. It will work even during long multiple `RENAME TABLE` operation. [#5875](https://github.com/ClickHouse/ClickHouse/pull/5875) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   More informative error messages will be displayed when ThreadPool cannot schedule a task for execution. This fixes [#5305](https://github.com/ClickHouse/ClickHouse/issues/5305) [#5801](https://github.com/ClickHouse/ClickHouse/pull/5801) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Inverting ngramSearch to be more intuitive [#5807](https://github.com/ClickHouse/ClickHouse/pull/5807) ([Danila Kutenin](https://github.com/danlark1))
+-   Add user parsing in HDFS engine builder [#5946](https://github.com/ClickHouse/ClickHouse/pull/5946) ([akonyaev90](https://github.com/akonyaev90))
+-   Update default value of `max_ast_elements parameter` [#5933](https://github.com/ClickHouse/ClickHouse/pull/5933) ([Artem Konovalov](https://github.com/izebit))
+-   Added a notion of obsolete settings. The obsolete setting `allow_experimental_low_cardinality_type` can be used with no effect. [0f15c01c6802f7ce1a1494c12c846be8c98944cd](https://github.com/ClickHouse/ClickHouse/commit/0f15c01c6802f7ce1a1494c12c846be8c98944cd) [Alexey Milovidov](https://github.com/alexey-milovidov)
+
+#### Performance Improvement {#performance-improvement-4}
+
+-   Increase number of streams to SELECT from Merge table for more uniform distribution of threads. Added setting `max_streams_multiplier_for_merge_tables`. This fixes [#5797](https://github.com/ClickHouse/ClickHouse/issues/5797) [#5915](https://github.com/ClickHouse/ClickHouse/pull/5915) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-7}
+
+-   Add a backward compatibility test for client-server interaction with different versions of clickhouse. [#5868](https://github.com/ClickHouse/ClickHouse/pull/5868) ([alesapin](https://github.com/alesapin))
+-   Test coverage information in every commit and pull request. [#5896](https://github.com/ClickHouse/ClickHouse/pull/5896) ([alesapin](https://github.com/alesapin))
+-   Cooperate with address sanitizer to support our custom allocators (`Arena` and `ArenaWithFreeLists`) for better debugging of “use-after-free” errors. [#5728](https://github.com/ClickHouse/ClickHouse/pull/5728) ([akuzm](https://github.com/akuzm))
+-   Switch to [LLVM libunwind implementation](https://github.com/llvm-mirror/libunwind) for C++ exception handling and for stack traces printing [#4828](https://github.com/ClickHouse/ClickHouse/pull/4828) ([Nikita Lapkov](https://github.com/laplab))
+-   Add two more warnings from -Weverything [#5923](https://github.com/ClickHouse/ClickHouse/pull/5923) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Allow to build ClickHouse with Memory Sanitizer. [#3949](https://github.com/ClickHouse/ClickHouse/pull/3949) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed ubsan report about `bitTest` function in fuzz test. [#5943](https://github.com/ClickHouse/ClickHouse/pull/5943) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Docker: added possibility to init a ClickHouse instance which requires authentication. [#5727](https://github.com/ClickHouse/ClickHouse/pull/5727) ([Korviakov Andrey](https://github.com/shurshun))
+-   Update librdkafka to version 1.1.0 [#5872](https://github.com/ClickHouse/ClickHouse/pull/5872) ([Ivan](https://github.com/abyss7))
+-   Add global timeout for integration tests and disable some of them in tests code. [#5741](https://github.com/ClickHouse/ClickHouse/pull/5741) ([alesapin](https://github.com/alesapin))
+-   Fix some ThreadSanitizer failures. [#5854](https://github.com/ClickHouse/ClickHouse/pull/5854) ([akuzm](https://github.com/akuzm))
+-   The `--no-undefined` option forces the linker to check all external names for existence while linking. It’s very useful to track real dependencies between libraries in the split build mode. [#5855](https://github.com/ClickHouse/ClickHouse/pull/5855) ([Ivan](https://github.com/abyss7))
+-   Added performance test for [#5797](https://github.com/ClickHouse/ClickHouse/issues/5797) [#5914](https://github.com/ClickHouse/ClickHouse/pull/5914) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed compatibility with gcc-7. [#5840](https://github.com/ClickHouse/ClickHouse/pull/5840) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added support for gcc-9. This fixes [#5717](https://github.com/ClickHouse/ClickHouse/issues/5717) [#5774](https://github.com/ClickHouse/ClickHouse/pull/5774) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed error when libunwind can be linked incorrectly. [#5948](https://github.com/ClickHouse/ClickHouse/pull/5948) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed a few warnings found by PVS-Studio. [#5921](https://github.com/ClickHouse/ClickHouse/pull/5921) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added initial support for `clang-tidy` static analyzer. [#5806](https://github.com/ClickHouse/ClickHouse/pull/5806) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Convert BSD/Linux endian macros( ‘be64toh’ and ‘htobe64’) to the Mac OS X equivalents [#5785](https://github.com/ClickHouse/ClickHouse/pull/5785) ([Fu Chen](https://github.com/fredchenbj))
+-   Improved integration tests guide. [#5796](https://github.com/ClickHouse/ClickHouse/pull/5796) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Fixing build at macosx + gcc9 [#5822](https://github.com/ClickHouse/ClickHouse/pull/5822) ([filimonov](https://github.com/filimonov))
+-   Fix a hard-to-spot typo: aggreAGte -\> aggregate. [#5753](https://github.com/ClickHouse/ClickHouse/pull/5753) ([akuzm](https://github.com/akuzm))
+-   Fix freebsd build [#5760](https://github.com/ClickHouse/ClickHouse/pull/5760) ([proller](https://github.com/proller))
+-   Add link to experimental YouTube channel to website [#5845](https://github.com/ClickHouse/ClickHouse/pull/5845) ([Ivan Blinkov](https://github.com/blinkov))
+-   CMake: add option for coverage flags: WITH_COVERAGE [#5776](https://github.com/ClickHouse/ClickHouse/pull/5776) ([proller](https://github.com/proller))
+-   Fix initial size of some inline PODArray’s. [#5787](https://github.com/ClickHouse/ClickHouse/pull/5787) ([akuzm](https://github.com/akuzm))
+-   clickhouse-server.postinst: fix os detection for centos 6 [#5788](https://github.com/ClickHouse/ClickHouse/pull/5788) ([proller](https://github.com/proller))
+-   Added Arch linux package generation. [#5719](https://github.com/ClickHouse/ClickHouse/pull/5719) ([Vladimir Chebotarev](https://github.com/excitoon))
+-   Split Common/config.h by libs (dbms) [#5715](https://github.com/ClickHouse/ClickHouse/pull/5715) ([proller](https://github.com/proller))
+-   Fixes for “Arcadia” build platform [#5795](https://github.com/ClickHouse/ClickHouse/pull/5795) ([proller](https://github.com/proller))
+-   Fixes for unconventional build (gcc9, no submodules) [#5792](https://github.com/ClickHouse/ClickHouse/pull/5792) ([proller](https://github.com/proller))
+-   Require explicit type in unalignedStore because it was proven to be bug-prone [#5791](https://github.com/ClickHouse/ClickHouse/pull/5791) ([akuzm](https://github.com/akuzm))
+-   Fixes MacOS build [#5830](https://github.com/ClickHouse/ClickHouse/pull/5830) ([filimonov](https://github.com/filimonov))
+-   Performance test concerning the new JIT feature with bigger dataset, as requested here [#5263](https://github.com/ClickHouse/ClickHouse/issues/5263) [#5887](https://github.com/ClickHouse/ClickHouse/pull/5887) ([Guillaume Tassery](https://github.com/YiuRULE))
+-   Run stateful tests in stress test [12693e568722f11e19859742f56428455501fd2a](https://github.com/ClickHouse/ClickHouse/commit/12693e568722f11e19859742f56428455501fd2a) ([alesapin](https://github.com/alesapin))
+
+#### Backward Incompatible Change {#backward-incompatible-change-7}
+
+-   `Kafka` is broken in this version.
+-   Enable `adaptive_index_granularity` = 10MB by default for new `MergeTree` tables. If you created new MergeTree tables on version 19.11+, downgrade to versions prior to 19.6 will be impossible. [#5628](https://github.com/ClickHouse/ClickHouse/pull/5628) ([alesapin](https://github.com/alesapin))
+-   Removed obsolete undocumented embedded dictionaries that were used by Yandex.Metrica. The functions `OSIn`, `SEIn`, `OSToRoot`, `SEToRoot`, `OSHierarchy`, `SEHierarchy` are no longer available. If you are using these functions, write email to clickhouse-feedback@yandex-team.com. Note: at the last moment we decided to keep these functions for a while. [#5780](https://github.com/ClickHouse/ClickHouse/pull/5780) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+## ClickHouse Release 19.10 {#clickhouse-release-19-10}
+
+### ClickHouse Release 19.10.1.5, 2019-07-12 {#clickhouse-release-19-10-1-5-2019-07-12}
+
+#### New Feature {#new-feature-7}
+
+-   Add new column codec: `T64`. Made for (U)IntX/EnumX/Data(Time)/DecimalX columns. It should be good for columns with constant or small range values. Codec itself allows enlarge or shrink data type without re-compression. [#5557](https://github.com/ClickHouse/ClickHouse/pull/5557) ([Artem Zuikov](https://github.com/4ertus2))
+-   Add database engine `MySQL` that allow to view all the tables in remote MySQL server [#5599](https://github.com/ClickHouse/ClickHouse/pull/5599) ([Winter Zhang](https://github.com/zhang2014))
+-   `bitmapContains` implementation. It’s 2x faster than `bitmapHasAny` if the second bitmap contains one element. [#5535](https://github.com/ClickHouse/ClickHouse/pull/5535) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Support for `crc32` function (with behaviour exactly as in MySQL or PHP). Do not use it if you need a hash function. [#5661](https://github.com/ClickHouse/ClickHouse/pull/5661) ([Remen Ivan](https://github.com/BHYCHIK))
+-   Implemented `SYSTEM START/STOP DISTRIBUTED SENDS` queries to control asynchronous inserts into `Distributed` tables. [#4935](https://github.com/ClickHouse/ClickHouse/pull/4935) ([Winter Zhang](https://github.com/zhang2014))
+
+#### Bug Fix {#bug-fix-22}
+
+-   Ignore query execution limits and max parts size for merge limits while executing mutations. [#5659](https://github.com/ClickHouse/ClickHouse/pull/5659) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix bug which may lead to deduplication of normal blocks (extremely rare) and insertion of duplicate blocks (more often). [#5549](https://github.com/ClickHouse/ClickHouse/pull/5549) ([alesapin](https://github.com/alesapin))
+-   Fix of function `arrayEnumerateUniqRanked` for arguments with empty arrays [#5559](https://github.com/ClickHouse/ClickHouse/pull/5559) ([proller](https://github.com/proller))
+-   Don’t subscribe to Kafka topics without intent to poll any messages. [#5698](https://github.com/ClickHouse/ClickHouse/pull/5698) ([Ivan](https://github.com/abyss7))
+-   Make setting `join_use_nulls` get no effect for types that cannot be inside Nullable [#5700](https://github.com/ClickHouse/ClickHouse/pull/5700) ([Olga Khvostikova](https://github.com/stavrolia))
+-   Fixed `Incorrect size of index granularity` errors [#5720](https://github.com/ClickHouse/ClickHouse/pull/5720) ([coraxster](https://github.com/coraxster))
+-   Fix Float to Decimal convert overflow [#5607](https://github.com/ClickHouse/ClickHouse/pull/5607) ([coraxster](https://github.com/coraxster))
+-   Flush buffer when `WriteBufferFromHDFS`’s destructor is called. This fixes writing into `HDFS`. [#5684](https://github.com/ClickHouse/ClickHouse/pull/5684) ([Xindong Peng](https://github.com/eejoin))
+
+#### Improvement {#improvement-7}
+
+-   Treat empty cells in `CSV` as default values when the setting `input_format_defaults_for_omitted_fields` is enabled. [#5625](https://github.com/ClickHouse/ClickHouse/pull/5625) ([akuzm](https://github.com/akuzm))
+-   Non-blocking loading of external dictionaries. [#5567](https://github.com/ClickHouse/ClickHouse/pull/5567) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Network timeouts can be dynamically changed for already established connections according to the settings. [#4558](https://github.com/ClickHouse/ClickHouse/pull/4558) ([Konstantin Podshumok](https://github.com/podshumok))
+-   Using “public_suffix_list” for functions `firstSignificantSubdomain`, `cutToFirstSignificantSubdomain`. It’s using a perfect hash table generated by `gperf` with a list generated from the file: https://publicsuffix.org/list/public_suffix_list.dat. (for example, now we recognize the domain `ac.uk` as non-significant). [#5030](https://github.com/ClickHouse/ClickHouse/pull/5030) ([Guillaume Tassery](https://github.com/YiuRULE))
+-   Adopted `IPv6` data type in system tables; unified client info columns in `system.processes` and `system.query_log` [#5640](https://github.com/ClickHouse/ClickHouse/pull/5640) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Using sessions for connections with MySQL compatibility protocol. #5476 [#5646](https://github.com/ClickHouse/ClickHouse/pull/5646) ([Yuriy Baranov](https://github.com/yurriy))
+-   Support more `ALTER` queries `ON CLUSTER`. [#5593](https://github.com/ClickHouse/ClickHouse/pull/5593) [#5613](https://github.com/ClickHouse/ClickHouse/pull/5613) ([sundyli](https://github.com/sundy-li))
+-   Support `<logger>` section in `clickhouse-local` config file. [#5540](https://github.com/ClickHouse/ClickHouse/pull/5540) ([proller](https://github.com/proller))
+-   Allow run query with `remote` table function in `clickhouse-local` [#5627](https://github.com/ClickHouse/ClickHouse/pull/5627) ([proller](https://github.com/proller))
+
+#### Performance Improvement {#performance-improvement-5}
+
+-   Add the possibility to write the final mark at the end of MergeTree columns. It allows to avoid useless reads for keys that are out of table data range. It is enabled only if adaptive index granularity is in use. [#5624](https://github.com/ClickHouse/ClickHouse/pull/5624) ([alesapin](https://github.com/alesapin))
+-   Improved performance of MergeTree tables on very slow filesystems by reducing number of `stat` syscalls. [#5648](https://github.com/ClickHouse/ClickHouse/pull/5648) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed performance degradation in reading from MergeTree tables that was introduced in version 19.6. Fixes #5631. [#5633](https://github.com/ClickHouse/ClickHouse/pull/5633) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-8}
+
+-   Implemented `TestKeeper` as an implementation of ZooKeeper interface used for testing [#5643](https://github.com/ClickHouse/ClickHouse/pull/5643) ([alexey-milovidov](https://github.com/alexey-milovidov)) ([levushkin aleksej](https://github.com/alexey-milovidov))
+-   From now on `.sql` tests can be run isolated by server, in parallel, with random database. It allows to run them faster, add new tests with custom server configurations, and be sure that different tests does not affect each other. [#5554](https://github.com/ClickHouse/ClickHouse/pull/5554) ([Ivan](https://github.com/abyss7))
+-   Remove `<name>` and `<metrics>` from performance tests [#5672](https://github.com/ClickHouse/ClickHouse/pull/5672) ([Olga Khvostikova](https://github.com/stavrolia))
+-   Fixed “select_format” performance test for `Pretty` formats [#5642](https://github.com/ClickHouse/ClickHouse/pull/5642) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+## ClickHouse Release 19.9 {#clickhouse-release-19-9}
+
+### ClickHouse Release 19.9.3.31, 2019-07-05 {#clickhouse-release-19-9-3-31-2019-07-05}
+
+#### Bug Fix {#bug-fix-23}
+
+-   Fix segfault in Delta codec which affects columns with values less than 32 bits size. The bug led to random memory corruption. [#5786](https://github.com/ClickHouse/ClickHouse/pull/5786) ([alesapin](https://github.com/alesapin))
+-   Fix rare bug in checking of part with LowCardinality column. [#5832](https://github.com/ClickHouse/ClickHouse/pull/5832) ([alesapin](https://github.com/alesapin))
+-   Fix segfault in TTL merge with non-physical columns in block. [#5819](https://github.com/ClickHouse/ClickHouse/pull/5819) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix potential infinite sleeping of low-priority queries. [#5842](https://github.com/ClickHouse/ClickHouse/pull/5842) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix how ClickHouse determines default time zone as UCT instead of UTC. [#5828](https://github.com/ClickHouse/ClickHouse/pull/5828) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix bug about executing distributed DROP/ALTER/TRUNCATE/OPTIMIZE ON CLUSTER queries on follower replica before leader replica. Now they will be executed directly on leader replica. [#5757](https://github.com/ClickHouse/ClickHouse/pull/5757) ([alesapin](https://github.com/alesapin))
+-   Fix race condition, which cause that some queries may not appear in query_log instantly after SYSTEM FLUSH LOGS query. [#5685](https://github.com/ClickHouse/ClickHouse/pull/5685) ([Anton Popov](https://github.com/CurtizJ))
+-   Added missing support for constant arguments to `evalMLModel` function. [#5820](https://github.com/ClickHouse/ClickHouse/pull/5820) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.9.2.4, 2019-06-24 {#clickhouse-release-19-9-2-4-2019-06-24}
+
+#### New Feature {#new-feature-8}
+
+-   Print information about frozen parts in `system.parts` table. [#5471](https://github.com/ClickHouse/ClickHouse/pull/5471) ([proller](https://github.com/proller))
+-   Ask client password on clickhouse-client start on tty if not set in arguments [#5092](https://github.com/ClickHouse/ClickHouse/pull/5092) ([proller](https://github.com/proller))
+-   Implement `dictGet` and `dictGetOrDefault` functions for Decimal types. [#5394](https://github.com/ClickHouse/ClickHouse/pull/5394) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Improvement {#improvement-8}
+
+-   Debian init: Add service stop timeout [#5522](https://github.com/ClickHouse/ClickHouse/pull/5522) ([proller](https://github.com/proller))
+-   Add setting forbidden by default to create table with suspicious types for LowCardinality [#5448](https://github.com/ClickHouse/ClickHouse/pull/5448) ([Olga Khvostikova](https://github.com/stavrolia))
+-   Regression functions return model weights when not used as State in function `evalMLMethod`. [#5411](https://github.com/ClickHouse/ClickHouse/pull/5411) ([Quid37](https://github.com/Quid37))
+-   Rename and improve regression methods. [#5492](https://github.com/ClickHouse/ClickHouse/pull/5492) ([Quid37](https://github.com/Quid37))
+-   Clearer interfaces of string searchers. [#5586](https://github.com/ClickHouse/ClickHouse/pull/5586) ([Danila Kutenin](https://github.com/danlark1))
+
+#### Bug Fix {#bug-fix-24}
+
+-   Fix potential data loss in Kafka [#5445](https://github.com/ClickHouse/ClickHouse/pull/5445) ([Ivan](https://github.com/abyss7))
+-   Fix potential infinite loop in `PrettySpace` format when called with zero columns [#5560](https://github.com/ClickHouse/ClickHouse/pull/5560) ([Olga Khvostikova](https://github.com/stavrolia))
+-   Fixed UInt32 overflow bug in linear models. Allow eval ML model for non-const model argument. [#5516](https://github.com/ClickHouse/ClickHouse/pull/5516) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   `ALTER TABLE ... DROP INDEX IF EXISTS ...` should not raise an exception if provided index does not exist [#5524](https://github.com/ClickHouse/ClickHouse/pull/5524) ([Gleb Novikov](https://github.com/NanoBjorn))
+-   Fix segfault with `bitmapHasAny` in scalar subquery [#5528](https://github.com/ClickHouse/ClickHouse/pull/5528) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Fixed error when replication connection pool does not retry to resolve host, even when DNS cache was dropped. [#5534](https://github.com/ClickHouse/ClickHouse/pull/5534) ([alesapin](https://github.com/alesapin))
+-   Fixed `ALTER ... MODIFY TTL` on ReplicatedMergeTree. [#5539](https://github.com/ClickHouse/ClickHouse/pull/5539) ([Anton Popov](https://github.com/CurtizJ))
+-   Fix INSERT into Distributed table with MATERIALIZED column [#5429](https://github.com/ClickHouse/ClickHouse/pull/5429) ([Azat Khuzhin](https://github.com/azat))
+-   Fix bad alloc when truncate Join storage [#5437](https://github.com/ClickHouse/ClickHouse/pull/5437) ([TCeason](https://github.com/TCeason))
+-   In recent versions of package tzdata some of files are symlinks now. The current mechanism for detecting default timezone gets broken and gives wrong names for some timezones. Now at least we force the timezone name to the contents of TZ if provided. [#5443](https://github.com/ClickHouse/ClickHouse/pull/5443) ([Ivan](https://github.com/abyss7))
+-   Fix some extremely rare cases with MultiVolnitsky searcher when the constant needles in sum are at least 16KB long. The algorithm missed or overwrote the previous results which can lead to the incorrect result of `multiSearchAny`. [#5588](https://github.com/ClickHouse/ClickHouse/pull/5588) ([Danila Kutenin](https://github.com/danlark1))
+-   Fix the issue when settings for ExternalData requests couldn’t use ClickHouse settings. Also, for now, settings `date_time_input_format` and `low_cardinality_allow_in_native_format` cannot be used because of the ambiguity of names (in external data it can be interpreted as table format and in the query it can be a setting). [#5455](https://github.com/ClickHouse/ClickHouse/pull/5455) ([Danila Kutenin](https://github.com/danlark1))
+-   Fix bug when parts were removed only from FS without dropping them from Zookeeper. [#5520](https://github.com/ClickHouse/ClickHouse/pull/5520) ([alesapin](https://github.com/alesapin))
+-   Remove debug logging from MySQL protocol [#5478](https://github.com/ClickHouse/ClickHouse/pull/5478) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Skip ZNONODE during DDL query processing [#5489](https://github.com/ClickHouse/ClickHouse/pull/5489) ([Azat Khuzhin](https://github.com/azat))
+-   Fix mix `UNION ALL` result column type. There were cases with inconsistent data and column types of resulting columns. [#5503](https://github.com/ClickHouse/ClickHouse/pull/5503) ([Artem Zuikov](https://github.com/4ertus2))
+-   Throw an exception on wrong integers in `dictGetT` functions instead of crash. [#5446](https://github.com/ClickHouse/ClickHouse/pull/5446) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix wrong element_count and load_factor for hashed dictionary in `system.dictionaries` table. [#5440](https://github.com/ClickHouse/ClickHouse/pull/5440) ([Azat Khuzhin](https://github.com/azat))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-9}
+
+-   Fixed build without `Brotli` HTTP compression support (`ENABLE_BROTLI=OFF` cmake variable). [#5521](https://github.com/ClickHouse/ClickHouse/pull/5521) ([Anton Yuzhaninov](https://github.com/citrin))
+-   Include roaring.h as roaring/roaring.h [#5523](https://github.com/ClickHouse/ClickHouse/pull/5523) ([Orivej Desh](https://github.com/orivej))
+-   Fix gcc9 warnings in hyperscan (#line directive is evil!) [#5546](https://github.com/ClickHouse/ClickHouse/pull/5546) ([Danila Kutenin](https://github.com/danlark1))
+-   Fix all warnings when compiling with gcc-9. Fix some contrib issues. Fix gcc9 ICE and submit it to bugzilla. [#5498](https://github.com/ClickHouse/ClickHouse/pull/5498) ([Danila Kutenin](https://github.com/danlark1))
+-   Fixed linking with lld [#5477](https://github.com/ClickHouse/ClickHouse/pull/5477) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Remove unused specializations in dictionaries [#5452](https://github.com/ClickHouse/ClickHouse/pull/5452) ([Artem Zuikov](https://github.com/4ertus2))
+-   Improvement performance tests for formatting and parsing tables for different types of files [#5497](https://github.com/ClickHouse/ClickHouse/pull/5497) ([Olga Khvostikova](https://github.com/stavrolia))
+-   Fixes for parallel test run [#5506](https://github.com/ClickHouse/ClickHouse/pull/5506) ([proller](https://github.com/proller))
+-   Docker: use configs from clickhouse-test [#5531](https://github.com/ClickHouse/ClickHouse/pull/5531) ([proller](https://github.com/proller))
+-   Fix compile for FreeBSD [#5447](https://github.com/ClickHouse/ClickHouse/pull/5447) ([proller](https://github.com/proller))
+-   Upgrade boost to 1.70 [#5570](https://github.com/ClickHouse/ClickHouse/pull/5570) ([proller](https://github.com/proller))
+-   Fix build clickhouse as submodule [#5574](https://github.com/ClickHouse/ClickHouse/pull/5574) ([proller](https://github.com/proller))
+-   Improve JSONExtract performance tests [#5444](https://github.com/ClickHouse/ClickHouse/pull/5444) ([Vitaly Baranov](https://github.com/vitlibar))
+
+## ClickHouse Release 19.8 {#clickhouse-release-19-8}
+
+### ClickHouse Release 19.8.3.8, 2019-06-11 {#clickhouse-release-19-8-3-8-2019-06-11}
+
+#### New Features {#new-features}
+
+-   Added functions to work with JSON [#4686](https://github.com/ClickHouse/ClickHouse/pull/4686) ([hcz](https://github.com/hczhcz)) [#5124](https://github.com/ClickHouse/ClickHouse/pull/5124). ([Vitaly Baranov](https://github.com/vitlibar))
+-   Add a function basename, with a similar behaviour to a basename function, which exists in a lot of languages (`os.path.basename` in python, `basename` in PHP, etc…). Work with both an UNIX-like path or a Windows path. [#5136](https://github.com/ClickHouse/ClickHouse/pull/5136) ([Guillaume Tassery](https://github.com/YiuRULE))
+-   Added `LIMIT n, m BY` or `LIMIT m OFFSET n BY` syntax to set offset of n for LIMIT BY clause. [#5138](https://github.com/ClickHouse/ClickHouse/pull/5138) ([Anton Popov](https://github.com/CurtizJ))
+-   Added new data type `SimpleAggregateFunction`, which allows to have columns with light aggregation in an `AggregatingMergeTree`. This can only be used with simple functions like `any`, `anyLast`, `sum`, `min`, `max`. [#4629](https://github.com/ClickHouse/ClickHouse/pull/4629) ([Boris Granveaud](https://github.com/bgranvea))
+-   Added support for non-constant arguments in function `ngramDistance` [#5198](https://github.com/ClickHouse/ClickHouse/pull/5198) ([Danila Kutenin](https://github.com/danlark1))
+-   Added functions `skewPop`, `skewSamp`, `kurtPop` and `kurtSamp` to compute for sequence skewness, sample skewness, kurtosis and sample kurtosis respectively. [#5200](https://github.com/ClickHouse/ClickHouse/pull/5200) ([hcz](https://github.com/hczhcz))
+-   Support rename operation for `MaterializeView` storage. [#5209](https://github.com/ClickHouse/ClickHouse/pull/5209) ([Guillaume Tassery](https://github.com/YiuRULE))
+-   Added server which allows connecting to ClickHouse using MySQL client. [#4715](https://github.com/ClickHouse/ClickHouse/pull/4715) ([Yuriy Baranov](https://github.com/yurriy))
+-   Add `toDecimal*OrZero` and `toDecimal*OrNull` functions. [#5291](https://github.com/ClickHouse/ClickHouse/pull/5291) ([Artem Zuikov](https://github.com/4ertus2))
+-   Support Decimal types in functions: `quantile`, `quantiles`, `median`, `quantileExactWeighted`, `quantilesExactWeighted`, medianExactWeighted. [#5304](https://github.com/ClickHouse/ClickHouse/pull/5304) ([Artem Zuikov](https://github.com/4ertus2))
+-   Added `toValidUTF8` function, which replaces all invalid UTF-8 characters by replacement character � (U+FFFD). [#5322](https://github.com/ClickHouse/ClickHouse/pull/5322) ([Danila Kutenin](https://github.com/danlark1))
+-   Added `format` function. Formatting constant pattern (simplified Python format pattern) with the strings listed in the arguments. [#5330](https://github.com/ClickHouse/ClickHouse/pull/5330) ([Danila Kutenin](https://github.com/danlark1))
+-   Added `system.detached_parts` table containing information about detached parts of `MergeTree` tables. [#5353](https://github.com/ClickHouse/ClickHouse/pull/5353) ([akuzm](https://github.com/akuzm))
+-   Added `ngramSearch` function to calculate the non-symmetric difference between needle and haystack. [#5418](https://github.com/ClickHouse/ClickHouse/pull/5418)[#5422](https://github.com/ClickHouse/ClickHouse/pull/5422) ([Danila Kutenin](https://github.com/danlark1))
+-   Implementation of basic machine learning methods (stochastic linear regression and logistic regression) using aggregate functions interface. Has different strategies for updating model weights (simple gradient descent, momentum method, Nesterov method). Also supports mini-batches of custom size. [#4943](https://github.com/ClickHouse/ClickHouse/pull/4943) ([Quid37](https://github.com/Quid37))
+-   Implementation of `geohashEncode` and `geohashDecode` functions. [#5003](https://github.com/ClickHouse/ClickHouse/pull/5003) ([Vasily Nemkov](https://github.com/Enmk))
+-   Added aggregate function `timeSeriesGroupSum`, which can aggregate different time series that sample timestamp not alignment. It will use linear interpolation between two sample timestamp and then sum time-series together. Added aggregate function `timeSeriesGroupRateSum`, which calculates the rate of time-series and then sum rates together. [#4542](https://github.com/ClickHouse/ClickHouse/pull/4542) ([Yangkuan Liu](https://github.com/LiuYangkuan))
+-   Added functions `IPv4CIDRtoIPv4Range` and `IPv6CIDRtoIPv6Range` to calculate the lower and higher bounds for an IP in the subnet using a CIDR. [#5095](https://github.com/ClickHouse/ClickHouse/pull/5095) ([Guillaume Tassery](https://github.com/YiuRULE))
+-   Add a X-ClickHouse-Summary header when we send a query using HTTP with enabled setting `send_progress_in_http_headers`. Return the usual information of X-ClickHouse-Progress, with additional information like how many rows and bytes were inserted in the query. [#5116](https://github.com/ClickHouse/ClickHouse/pull/5116) ([Guillaume Tassery](https://github.com/YiuRULE))
+
+#### Improvements {#improvements}
+
+-   Added `max_parts_in_total` setting for MergeTree family of tables (default: 100 000) that prevents unsafe specification of partition key #5166. [#5171](https://github.com/ClickHouse/ClickHouse/pull/5171) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   `clickhouse-obfuscator`: derive seed for individual columns by combining initial seed with column name, not column position. This is intended to transform datasets with multiple related tables, so that tables will remain JOINable after transformation. [#5178](https://github.com/ClickHouse/ClickHouse/pull/5178) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added functions `JSONExtractRaw`, `JSONExtractKeyAndValues`. Renamed functions `jsonExtract<type>` to `JSONExtract<type>`. When something goes wrong these functions return the correspondent values, not `NULL`. Modified function `JSONExtract`, now it gets the return type from its last parameter and does not inject nullables. Implemented fallback to RapidJSON in case AVX2 instructions are not available. Simdjson library updated to a new version. [#5235](https://github.com/ClickHouse/ClickHouse/pull/5235) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Now `if` and `multiIf` functions do not rely on the condition’s `Nullable`, but rely on the branches for sql compatibility. [#5238](https://github.com/ClickHouse/ClickHouse/pull/5238) ([Jian Wu](https://github.com/janplus))
+-   `In` predicate now generates `Null` result from `Null` input like the `Equal` function. [#5152](https://github.com/ClickHouse/ClickHouse/pull/5152) ([Jian Wu](https://github.com/janplus))
+-   Check the time limit every (flush_interval / poll_timeout) number of rows from Kafka. This allows to break the reading from Kafka consumer more frequently and to check the time limits for the top-level streams [#5249](https://github.com/ClickHouse/ClickHouse/pull/5249) ([Ivan](https://github.com/abyss7))
+-   Link rdkafka with bundled SASL. It should allow to use SASL SCRAM authentication [#5253](https://github.com/ClickHouse/ClickHouse/pull/5253) ([Ivan](https://github.com/abyss7))
+-   Batched version of RowRefList for ALL JOINS. [#5267](https://github.com/ClickHouse/ClickHouse/pull/5267) ([Artem Zuikov](https://github.com/4ertus2))
+-   clickhouse-server: more informative listen error messages. [#5268](https://github.com/ClickHouse/ClickHouse/pull/5268) ([proller](https://github.com/proller))
+-   Support dictionaries in clickhouse-copier for functions in `<sharding_key>` [#5270](https://github.com/ClickHouse/ClickHouse/pull/5270) ([proller](https://github.com/proller))
+-   Add new setting `kafka_commit_every_batch` to regulate Kafka committing policy.
+    It allows to set commit mode: after every batch of messages is handled, or after the whole block is written to the storage. It’s a trade-off between losing some messages or reading them twice in some extreme situations. [#5308](https://github.com/ClickHouse/ClickHouse/pull/5308) ([Ivan](https://github.com/abyss7))
+-   Make `windowFunnel` support other Unsigned Integer Types. [#5320](https://github.com/ClickHouse/ClickHouse/pull/5320) ([sundyli](https://github.com/sundy-li))
+-   Allow to shadow virtual column `_table` in Merge engine. [#5325](https://github.com/ClickHouse/ClickHouse/pull/5325) ([Ivan](https://github.com/abyss7))
+-   Make `sequenceMatch` aggregate functions support other unsigned Integer types [#5339](https://github.com/ClickHouse/ClickHouse/pull/5339) ([sundyli](https://github.com/sundy-li))
+-   Better error messages if checksum mismatch is most likely caused by hardware failures. [#5355](https://github.com/ClickHouse/ClickHouse/pull/5355) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Check that underlying tables support sampling for `StorageMerge` [#5366](https://github.com/ClickHouse/ClickHouse/pull/5366) ([Ivan](https://github.com/abyss7))
+-   Сlose MySQL connections after their usage in external dictionaries. It is related to issue #893. [#5395](https://github.com/ClickHouse/ClickHouse/pull/5395) ([Clément Rodriguez](https://github.com/clemrodriguez))
+-   Improvements of MySQL Wire Protocol. Changed name of format to MySQLWire. Using RAII for calling RSA_free. Disabling SSL if context cannot be created. [#5419](https://github.com/ClickHouse/ClickHouse/pull/5419) ([Yuriy Baranov](https://github.com/yurriy))
+-   clickhouse-client: allow to run with unaccessable history file (read-only, no disk space, file is directory, …). [#5431](https://github.com/ClickHouse/ClickHouse/pull/5431) ([proller](https://github.com/proller))
+-   Respect query settings in asynchronous INSERTs into Distributed tables. [#4936](https://github.com/ClickHouse/ClickHouse/pull/4936) ([TCeason](https://github.com/TCeason))
+-   Renamed functions `leastSqr` to `simpleLinearRegression`, `LinearRegression` to `linearRegression`, `LogisticRegression` to `logisticRegression`. [#5391](https://github.com/ClickHouse/ClickHouse/pull/5391) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+
+#### Performance Improvements {#performance-improvements}
+
+-   Parallelize processing of parts of non-replicated MergeTree tables in ALTER MODIFY query. [#4639](https://github.com/ClickHouse/ClickHouse/pull/4639) ([Ivan Kush](https://github.com/IvanKush))
+-   Optimizations in regular expressions extraction. [#5193](https://github.com/ClickHouse/ClickHouse/pull/5193) [#5191](https://github.com/ClickHouse/ClickHouse/pull/5191) ([Danila Kutenin](https://github.com/danlark1))
+-   Do not add right join key column to join result if it’s used only in join on section. [#5260](https://github.com/ClickHouse/ClickHouse/pull/5260) ([Artem Zuikov](https://github.com/4ertus2))
+-   Freeze the Kafka buffer after first empty response. It avoids multiple invokations of `ReadBuffer::next()` for empty result in some row-parsing streams. [#5283](https://github.com/ClickHouse/ClickHouse/pull/5283) ([Ivan](https://github.com/abyss7))
+-   `concat` function optimization for multiple arguments. [#5357](https://github.com/ClickHouse/ClickHouse/pull/5357) ([Danila Kutenin](https://github.com/danlark1))
+-   Query optimisation. Allow push down IN statement while rewriting commа/cross join into inner one. [#5396](https://github.com/ClickHouse/ClickHouse/pull/5396) ([Artem Zuikov](https://github.com/4ertus2))
+-   Upgrade our LZ4 implementation with reference one to have faster decompression. [#5070](https://github.com/ClickHouse/ClickHouse/pull/5070) ([Danila Kutenin](https://github.com/danlark1))
+-   Implemented MSD radix sort (based on kxsort), and partial sorting. [#5129](https://github.com/ClickHouse/ClickHouse/pull/5129) ([Evgenii Pravda](https://github.com/kvinty))
+
+#### Bug Fixes {#bug-fixes}
+
+-   Fix push require columns with join [#5192](https://github.com/ClickHouse/ClickHouse/pull/5192) ([Winter Zhang](https://github.com/zhang2014))
+-   Fixed bug, when ClickHouse is run by systemd, the command `sudo service clickhouse-server forcerestart` was not working as expected. [#5204](https://github.com/ClickHouse/ClickHouse/pull/5204) ([proller](https://github.com/proller))
+-   Fix http error codes in DataPartsExchange (interserver http server on 9009 port always returned code 200, even on errors). [#5216](https://github.com/ClickHouse/ClickHouse/pull/5216) ([proller](https://github.com/proller))
+-   Fix SimpleAggregateFunction for String longer than MAX_SMALL_STRING_SIZE [#5311](https://github.com/ClickHouse/ClickHouse/pull/5311) ([Azat Khuzhin](https://github.com/azat))
+-   Fix error for `Decimal` to `Nullable(Decimal)` conversion in IN. Support other Decimal to Decimal conversions (including different scales). [#5350](https://github.com/ClickHouse/ClickHouse/pull/5350) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed FPU clobbering in simdjson library that lead to wrong calculation of `uniqHLL` and `uniqCombined` aggregate function and math functions such as `log`. [#5354](https://github.com/ClickHouse/ClickHouse/pull/5354) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed handling mixed const/nonconst cases in JSON functions. [#5435](https://github.com/ClickHouse/ClickHouse/pull/5435) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fix `retention` function. Now all conditions that satisfy in a row of data are added to the data state. [#5119](https://github.com/ClickHouse/ClickHouse/pull/5119) ([小路](https://github.com/nicelulu))
+-   Fix result type for `quantileExact` with Decimals. [#5304](https://github.com/ClickHouse/ClickHouse/pull/5304) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Documentation {#documentation}
+
+-   Translate documentation for `CollapsingMergeTree` to chinese. [#5168](https://github.com/ClickHouse/ClickHouse/pull/5168) ([张风啸](https://github.com/AlexZFX))
+-   Translate some documentation about table engines to chinese.
+    [#5134](https://github.com/ClickHouse/ClickHouse/pull/5134)
+    [#5328](https://github.com/ClickHouse/ClickHouse/pull/5328)
+    ([never lee](https://github.com/neverlee))
+
+#### Build/Testing/Packaging Improvements {#buildtestingpackaging-improvements}
+
+-   Fix some sanitizer reports that show probable use-after-free.[#5139](https://github.com/ClickHouse/ClickHouse/pull/5139) [#5143](https://github.com/ClickHouse/ClickHouse/pull/5143) [#5393](https://github.com/ClickHouse/ClickHouse/pull/5393) ([Ivan](https://github.com/abyss7))
+-   Move performance tests out of separate directories for convenience. [#5158](https://github.com/ClickHouse/ClickHouse/pull/5158) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix incorrect performance tests. [#5255](https://github.com/ClickHouse/ClickHouse/pull/5255) ([alesapin](https://github.com/alesapin))
+-   Added a tool to calculate checksums caused by bit flips to debug hardware issues. [#5334](https://github.com/ClickHouse/ClickHouse/pull/5334) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Make runner script more usable. [#5340](https://github.com/ClickHouse/ClickHouse/pull/5340)[#5360](https://github.com/ClickHouse/ClickHouse/pull/5360) ([filimonov](https://github.com/filimonov))
+-   Add small instruction how to write performance tests. [#5408](https://github.com/ClickHouse/ClickHouse/pull/5408) ([alesapin](https://github.com/alesapin))
+-   Add ability to make substitutions in create, fill and drop query in performance tests [#5367](https://github.com/ClickHouse/ClickHouse/pull/5367) ([Olga Khvostikova](https://github.com/stavrolia))
+
+## ClickHouse Release 19.7 {#clickhouse-release-19-7}
+
+### ClickHouse Release 19.7.5.29, 2019-07-05 {#clickhouse-release-19-7-5-29-2019-07-05}
+
+#### Bug Fix {#bug-fix-25}
+
+-   Fix performance regression in some queries with JOIN. [#5192](https://github.com/ClickHouse/ClickHouse/pull/5192) ([Winter Zhang](https://github.com/zhang2014))
+
+### ClickHouse Release 19.7.5.27, 2019-06-09 {#clickhouse-release-19-7-5-27-2019-06-09}
+
+#### New Features {#new-features-1}
+
+-   Added bitmap related functions `bitmapHasAny` and `bitmapHasAll` analogous to `hasAny` and `hasAll` functions for arrays. [#5279](https://github.com/ClickHouse/ClickHouse/pull/5279) ([Sergi Vladykin](https://github.com/svladykin))
+
+#### Bug Fixes {#bug-fixes-1}
+
+-   Fix segfault on `minmax` INDEX with Null value. [#5246](https://github.com/ClickHouse/ClickHouse/pull/5246) ([Nikita Vasilev](https://github.com/nikvas0))
+-   Mark all input columns in LIMIT BY as required output. It fixes ‘Not found column’ error in some distributed queries. [#5407](https://github.com/ClickHouse/ClickHouse/pull/5407) ([Constantin S. Pan](https://github.com/kvap))
+-   Fix “Column ‘0’ already exists” error in `SELECT .. PREWHERE` on column with DEFAULT [#5397](https://github.com/ClickHouse/ClickHouse/pull/5397) ([proller](https://github.com/proller))
+-   Fix `ALTER MODIFY TTL` query on `ReplicatedMergeTree`. [#5539](https://github.com/ClickHouse/ClickHouse/pull/5539/commits) ([Anton Popov](https://github.com/CurtizJ))
+-   Don’t crash the server when Kafka consumers have failed to start. [#5285](https://github.com/ClickHouse/ClickHouse/pull/5285) ([Ivan](https://github.com/abyss7))
+-   Fixed bitmap functions produce wrong result. [#5359](https://github.com/ClickHouse/ClickHouse/pull/5359) ([Andy Yang](https://github.com/andyyzh))
+-   Fix element_count for hashed dictionary (do not include duplicates) [#5440](https://github.com/ClickHouse/ClickHouse/pull/5440) ([Azat Khuzhin](https://github.com/azat))
+-   Use contents of environment variable TZ as the name for timezone. It helps to correctly detect default timezone in some cases.[#5443](https://github.com/ClickHouse/ClickHouse/pull/5443) ([Ivan](https://github.com/abyss7))
+-   Do not try to convert integers in `dictGetT` functions, because it does not work correctly. Throw an exception instead. [#5446](https://github.com/ClickHouse/ClickHouse/pull/5446) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix settings in ExternalData HTTP request. [#5455](https://github.com/ClickHouse/ClickHouse/pull/5455) ([Danila
+    Kutenin](https://github.com/danlark1))
+-   Fix bug when parts were removed only from FS without dropping them from Zookeeper. [#5520](https://github.com/ClickHouse/ClickHouse/pull/5520) ([alesapin](https://github.com/alesapin))
+-   Fix segmentation fault in `bitmapHasAny` function. [#5528](https://github.com/ClickHouse/ClickHouse/pull/5528) ([Zhichang Yu](https://github.com/yuzhichang))
+-   Fixed error when replication connection pool does not retry to resolve host, even when DNS cache was dropped. [#5534](https://github.com/ClickHouse/ClickHouse/pull/5534) ([alesapin](https://github.com/alesapin))
+-   Fixed `DROP INDEX IF EXISTS` query. Now `ALTER TABLE ... DROP INDEX IF EXISTS ...` query does not raise an exception if provided index does not exist. [#5524](https://github.com/ClickHouse/ClickHouse/pull/5524) ([Gleb Novikov](https://github.com/NanoBjorn))
+-   Fix union all supertype column. There were cases with inconsistent data and column types of resulting columns. [#5503](https://github.com/ClickHouse/ClickHouse/pull/5503) ([Artem Zuikov](https://github.com/4ertus2))
+-   Skip ZNONODE during DDL query processing. Before if another node removes the znode in task queue, the one that
+    did not process it, but already get list of children, will terminate the DDLWorker thread. [#5489](https://github.com/ClickHouse/ClickHouse/pull/5489) ([Azat Khuzhin](https://github.com/azat))
+-   Fix INSERT into Distributed() table with MATERIALIZED column. [#5429](https://github.com/ClickHouse/ClickHouse/pull/5429) ([Azat Khuzhin](https://github.com/azat))
+
+### ClickHouse Release 19.7.3.9, 2019-05-30 {#clickhouse-release-19-7-3-9-2019-05-30}
+
+#### New Features {#new-features-2}
+
+-   Allow to limit the range of a setting that can be specified by user.
+    These constraints can be set up in user settings profile.
+    [#4931](https://github.com/ClickHouse/ClickHouse/pull/4931) ([Vitaly
+    Baranov](https://github.com/vitlibar))
+-   Add a second version of the function `groupUniqArray` with an optional
+    `max_size` parameter that limits the size of the resulting array. This
+    behavior is similar to `groupArray(max_size)(x)` function.
+    [#5026](https://github.com/ClickHouse/ClickHouse/pull/5026) ([Guillaume
+    Tassery](https://github.com/YiuRULE))
+-   For TSVWithNames/CSVWithNames input file formats, column order can now be
+    determined from file header. This is controlled by
+    `input_format_with_names_use_header` parameter.
+    [#5081](https://github.com/ClickHouse/ClickHouse/pull/5081)
+    ([Alexander](https://github.com/Akazz))
+
+#### Bug Fixes {#bug-fixes-2}
+
+-   Crash with uncompressed_cache + JOIN during merge (#5197)
+    [#5133](https://github.com/ClickHouse/ClickHouse/pull/5133) ([Danila
+    Kutenin](https://github.com/danlark1))
+-   Segmentation fault on a clickhouse-client query to system tables. #5066
+    [#5127](https://github.com/ClickHouse/ClickHouse/pull/5127)
+    ([Ivan](https://github.com/abyss7))
+-   Data loss on heavy load via KafkaEngine (#4736)
+    [#5080](https://github.com/ClickHouse/ClickHouse/pull/5080)
+    ([Ivan](https://github.com/abyss7))
+-   Fixed very rare data race condition that could happen when executing a query with UNION ALL involving at least two SELECTs from system.columns, system.tables, system.parts, system.parts_tables or tables of Merge family and performing ALTER of columns of the related tables concurrently. [#5189](https://github.com/ClickHouse/ClickHouse/pull/5189) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Performance Improvements {#performance-improvements-1}
+
+-   Use radix sort for sorting by single numeric column in `ORDER BY` without
+    `LIMIT`. [#5106](https://github.com/ClickHouse/ClickHouse/pull/5106),
+    [#4439](https://github.com/ClickHouse/ClickHouse/pull/4439)
+    ([Evgenii Pravda](https://github.com/kvinty),
+    [alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Documentation {#documentation-1}
+
+-   Translate documentation for some table engines to Chinese.
+    [#5107](https://github.com/ClickHouse/ClickHouse/pull/5107),
+    [#5094](https://github.com/ClickHouse/ClickHouse/pull/5094),
+    [#5087](https://github.com/ClickHouse/ClickHouse/pull/5087)
+    ([张风啸](https://github.com/AlexZFX)),
+    [#5068](https://github.com/ClickHouse/ClickHouse/pull/5068) ([never
+    lee](https://github.com/neverlee))
+
+#### Build/Testing/Packaging Improvements {#buildtestingpackaging-improvements-1}
+
+-   Print UTF-8 characters properly in `clickhouse-test`.
+    [#5084](https://github.com/ClickHouse/ClickHouse/pull/5084)
+    ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add command line parameter for clickhouse-client to always load suggestion
+    data. [#5102](https://github.com/ClickHouse/ClickHouse/pull/5102)
+    ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Resolve some of PVS-Studio warnings.
+    [#5082](https://github.com/ClickHouse/ClickHouse/pull/5082)
+    ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Update LZ4 [#5040](https://github.com/ClickHouse/ClickHouse/pull/5040) ([Danila
+    Kutenin](https://github.com/danlark1))
+-   Add gperf to build requirements for upcoming pull request #5030.
+    [#5110](https://github.com/ClickHouse/ClickHouse/pull/5110)
+    ([proller](https://github.com/proller))
+
+## ClickHouse Release 19.6 {#clickhouse-release-19-6}
+
+### ClickHouse Release 19.6.3.18, 2019-06-13 {#clickhouse-release-19-6-3-18-2019-06-13}
+
+#### Bug Fixes {#bug-fixes-3}
+
+-   Fixed IN condition pushdown for queries from table functions `mysql` and `odbc` and corresponding table engines. This fixes #3540 and #2384. [#5313](https://github.com/ClickHouse/ClickHouse/pull/5313) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix deadlock in Zookeeper. [#5297](https://github.com/ClickHouse/ClickHouse/pull/5297) ([github1youlc](https://github.com/github1youlc))
+-   Allow quoted decimals in CSV. [#5284](https://github.com/ClickHouse/ClickHouse/pull/5284) ([Artem Zuikov](https://github.com/4ertus2)
+-   Disallow conversion from float Inf/NaN into Decimals (throw exception). [#5282](https://github.com/ClickHouse/ClickHouse/pull/5282) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix data race in rename query. [#5247](https://github.com/ClickHouse/ClickHouse/pull/5247) ([Winter Zhang](https://github.com/zhang2014))
+-   Temporarily disable LFAlloc. Usage of LFAlloc might lead to a lot of MAP_FAILED in allocating UncompressedCache and in a result to crashes of queries at high loaded servers. [cfdba93](https://github.com/ClickHouse/ClickHouse/commit/cfdba938ce22f16efeec504f7f90206a515b1280)([Danila Kutenin](https://github.com/danlark1))
+
+### ClickHouse Release 19.6.2.11, 2019-05-13 {#clickhouse-release-19-6-2-11-2019-05-13}
+
+#### New Features {#new-features-3}
+
+-   TTL expressions for columns and tables. [#4212](https://github.com/ClickHouse/ClickHouse/pull/4212) ([Anton Popov](https://github.com/CurtizJ))
+-   Added support for `brotli` compression for HTTP responses (Accept-Encoding: br) [#4388](https://github.com/ClickHouse/ClickHouse/pull/4388) ([Mikhail](https://github.com/fandyushin))
+-   Added new function `isValidUTF8` for checking whether a set of bytes is correctly utf-8 encoded. [#4934](https://github.com/ClickHouse/ClickHouse/pull/4934) ([Danila Kutenin](https://github.com/danlark1))
+-   Add new load balancing policy `first_or_random` which sends queries to the first specified host and if it’s inaccessible send queries to random hosts of shard. Useful for cross-replication topology setups. [#5012](https://github.com/ClickHouse/ClickHouse/pull/5012) ([nvartolomei](https://github.com/nvartolomei))
+
+#### Experimental Features {#experimental-features-1}
+
+-   Add setting `index_granularity_bytes` (adaptive index granularity) for MergeTree\* tables family. [#4826](https://github.com/ClickHouse/ClickHouse/pull/4826) ([alesapin](https://github.com/alesapin))
+
+#### Improvements {#improvements-1}
+
+-   Added support for non-constant and negative size and length arguments for function `substringUTF8`. [#4989](https://github.com/ClickHouse/ClickHouse/pull/4989) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Disable push-down to right table in left join, left table in right join, and both tables in full join. This fixes wrong JOIN results in some cases. [#4846](https://github.com/ClickHouse/ClickHouse/pull/4846) ([Ivan](https://github.com/abyss7))
+-   `clickhouse-copier`: auto upload task configuration from `--task-file` option [#4876](https://github.com/ClickHouse/ClickHouse/pull/4876) ([proller](https://github.com/proller))
+-   Added typos handler for storage factory and table functions factory. [#4891](https://github.com/ClickHouse/ClickHouse/pull/4891) ([Danila Kutenin](https://github.com/danlark1))
+-   Support asterisks and qualified asterisks for multiple joins without subqueries [#4898](https://github.com/ClickHouse/ClickHouse/pull/4898) ([Artem Zuikov](https://github.com/4ertus2))
+-   Make missing column error message more user friendly. [#4915](https://github.com/ClickHouse/ClickHouse/pull/4915) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Performance Improvements {#performance-improvements-2}
+
+-   Significant speedup of ASOF JOIN [#4924](https://github.com/ClickHouse/ClickHouse/pull/4924) ([Martijn Bakker](https://github.com/Gladdy))
+
+#### Backward Incompatible Changes {#backward-incompatible-changes}
+
+-   HTTP header `Query-Id` was renamed to `X-ClickHouse-Query-Id` for consistency. [#4972](https://github.com/ClickHouse/ClickHouse/pull/4972) ([Mikhail](https://github.com/fandyushin))
+
+#### Bug Fixes {#bug-fixes-4}
+
+-   Fixed potential null pointer dereference in `clickhouse-copier`. [#4900](https://github.com/ClickHouse/ClickHouse/pull/4900) ([proller](https://github.com/proller))
+-   Fixed error on query with JOIN + ARRAY JOIN [#4938](https://github.com/ClickHouse/ClickHouse/pull/4938) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed hanging on start of the server when a dictionary depends on another dictionary via a database with engine=Dictionary. [#4962](https://github.com/ClickHouse/ClickHouse/pull/4962) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Partially fix distributed_product_mode = local. It’s possible to allow columns of local tables in where/having/order by/… via table aliases. Throw exception if table does not have alias. There’s not possible to access to the columns without table aliases yet. [#4986](https://github.com/ClickHouse/ClickHouse/pull/4986) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix potentially wrong result for `SELECT DISTINCT` with `JOIN` [#5001](https://github.com/ClickHouse/ClickHouse/pull/5001) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed very rare data race condition that could happen when executing a query with UNION ALL involving at least two SELECTs from system.columns, system.tables, system.parts, system.parts_tables or tables of Merge family and performing ALTER of columns of the related tables concurrently. [#5189](https://github.com/ClickHouse/ClickHouse/pull/5189) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Build/Testing/Packaging Improvements {#buildtestingpackaging-improvements-2}
+
+-   Fixed test failures when running clickhouse-server on different host [#4713](https://github.com/ClickHouse/ClickHouse/pull/4713) ([Vasily Nemkov](https://github.com/Enmk))
+-   clickhouse-test: Disable color control sequences in non tty environment. [#4937](https://github.com/ClickHouse/ClickHouse/pull/4937) ([alesapin](https://github.com/alesapin))
+-   clickhouse-test: Allow use any test database (remove `test.` qualification where it possible) [#5008](https://github.com/ClickHouse/ClickHouse/pull/5008) ([proller](https://github.com/proller))
+-   Fix ubsan errors [#5037](https://github.com/ClickHouse/ClickHouse/pull/5037) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Yandex LFAlloc was added to ClickHouse to allocate MarkCache and UncompressedCache data in different ways to catch segfaults more reliable [#4995](https://github.com/ClickHouse/ClickHouse/pull/4995) ([Danila Kutenin](https://github.com/danlark1))
+-   Python util to help with backports and changelogs. [#4949](https://github.com/ClickHouse/ClickHouse/pull/4949) ([Ivan](https://github.com/abyss7))
+
+## ClickHouse Release 19.5 {#clickhouse-release-19-5}
+
+### ClickHouse Release 19.5.4.22, 2019-05-13 {#clickhouse-release-19-5-4-22-2019-05-13}
+
+#### Bug Fixes {#bug-fixes-5}
+
+-   Fixed possible crash in bitmap\* functions [#5220](https://github.com/ClickHouse/ClickHouse/pull/5220) [#5228](https://github.com/ClickHouse/ClickHouse/pull/5228) ([Andy Yang](https://github.com/andyyzh))
+-   Fixed very rare data race condition that could happen when executing a query with UNION ALL involving at least two SELECTs from system.columns, system.tables, system.parts, system.parts_tables or tables of Merge family and performing ALTER of columns of the related tables concurrently. [#5189](https://github.com/ClickHouse/ClickHouse/pull/5189) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed error `Set for IN is not created yet in case of using single LowCardinality column in the left part of IN`. This error happened if LowCardinality column was the part of primary key. #5031 [#5154](https://github.com/ClickHouse/ClickHouse/pull/5154) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Modification of retention function: If a row satisfies both the first and NTH condition, only the first satisfied condition is added to the data state. Now all conditions that satisfy in a row of data are added to the data state. [#5119](https://github.com/ClickHouse/ClickHouse/pull/5119) ([小路](https://github.com/nicelulu))
+
+### ClickHouse Release 19.5.3.8, 2019-04-18 {#clickhouse-release-19-5-3-8-2019-04-18}
+
+#### Bug Fixes {#bug-fixes-6}
+
+-   Fixed type of setting `max_partitions_per_insert_block` from boolean to UInt64. [#5028](https://github.com/ClickHouse/ClickHouse/pull/5028) ([Mohammad Hossein Sekhavat](https://github.com/mhsekhavat))
+
+### ClickHouse Release 19.5.2.6, 2019-04-15 {#clickhouse-release-19-5-2-6-2019-04-15}
+
+#### New Features {#new-features-4}
+
+-   [Hyperscan](https://github.com/intel/hyperscan) multiple regular expression matching was added (functions `multiMatchAny`, `multiMatchAnyIndex`, `multiFuzzyMatchAny`, `multiFuzzyMatchAnyIndex`). [#4780](https://github.com/ClickHouse/ClickHouse/pull/4780), [#4841](https://github.com/ClickHouse/ClickHouse/pull/4841) ([Danila Kutenin](https://github.com/danlark1))
+-   `multiSearchFirstPosition` function was added. [#4780](https://github.com/ClickHouse/ClickHouse/pull/4780) ([Danila Kutenin](https://github.com/danlark1))
+-   Implement the predefined expression filter per row for tables. [#4792](https://github.com/ClickHouse/ClickHouse/pull/4792) ([Ivan](https://github.com/abyss7))
+-   A new type of data skipping indices based on bloom filters (can be used for `equal`, `in` and `like` functions). [#4499](https://github.com/ClickHouse/ClickHouse/pull/4499) ([Nikita Vasilev](https://github.com/nikvas0))
+-   Added `ASOF JOIN` which allows to run queries that join to the most recent value known. [#4774](https://github.com/ClickHouse/ClickHouse/pull/4774) [#4867](https://github.com/ClickHouse/ClickHouse/pull/4867) [#4863](https://github.com/ClickHouse/ClickHouse/pull/4863) [#4875](https://github.com/ClickHouse/ClickHouse/pull/4875) ([Martijn Bakker](https://github.com/Gladdy), [Artem Zuikov](https://github.com/4ertus2))
+-   Rewrite multiple `COMMA JOIN` to `CROSS JOIN`. Then rewrite them to `INNER JOIN` if possible. [#4661](https://github.com/ClickHouse/ClickHouse/pull/4661) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Improvement {#improvement-9}
+
+-   `topK` and `topKWeighted` now supports custom `loadFactor` (fixes issue [#4252](https://github.com/ClickHouse/ClickHouse/issues/4252)). [#4634](https://github.com/ClickHouse/ClickHouse/pull/4634) ([Kirill Danshin](https://github.com/kirillDanshin))
+-   Allow to use `parallel_replicas_count > 1` even for tables without sampling (the setting is simply ignored for them). In previous versions it was lead to exception. [#4637](https://github.com/ClickHouse/ClickHouse/pull/4637) ([Alexey Elymanov](https://github.com/digitalist))
+-   Support for `CREATE OR REPLACE VIEW`. Allow to create a view or set a new definition in a single statement. [#4654](https://github.com/ClickHouse/ClickHouse/pull/4654) ([Boris Granveaud](https://github.com/bgranvea))
+-   `Buffer` table engine now supports `PREWHERE`. [#4671](https://github.com/ClickHouse/ClickHouse/pull/4671) ([Yangkuan Liu](https://github.com/LiuYangkuan))
+-   Add ability to start replicated table without metadata in zookeeper in `readonly` mode. [#4691](https://github.com/ClickHouse/ClickHouse/pull/4691) ([alesapin](https://github.com/alesapin))
+-   Fixed flicker of progress bar in clickhouse-client. The issue was most noticeable when using `FORMAT Null` with streaming queries. [#4811](https://github.com/ClickHouse/ClickHouse/pull/4811) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Allow to disable functions with `hyperscan` library on per user basis to limit potentially excessive and uncontrolled resource usage. [#4816](https://github.com/ClickHouse/ClickHouse/pull/4816) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add version number logging in all errors. [#4824](https://github.com/ClickHouse/ClickHouse/pull/4824) ([proller](https://github.com/proller))
+-   Added restriction to the `multiMatch` functions which requires string size to fit into `unsigned int`. Also added the number of arguments limit to the `multiSearch` functions. [#4834](https://github.com/ClickHouse/ClickHouse/pull/4834) ([Danila Kutenin](https://github.com/danlark1))
+-   Improved usage of scratch space and error handling in Hyperscan. [#4866](https://github.com/ClickHouse/ClickHouse/pull/4866) ([Danila Kutenin](https://github.com/danlark1))
+-   Fill `system.graphite_detentions` from a table config of `*GraphiteMergeTree` engine tables. [#4584](https://github.com/ClickHouse/ClickHouse/pull/4584) ([Mikhail f. Shiryaev](https://github.com/Felixoid))
+-   Rename `trigramDistance` function to `ngramDistance` and add more functions with `CaseInsensitive` and `UTF`. [#4602](https://github.com/ClickHouse/ClickHouse/pull/4602) ([Danila Kutenin](https://github.com/danlark1))
+-   Improved data skipping indices calculation. [#4640](https://github.com/ClickHouse/ClickHouse/pull/4640) ([Nikita Vasilev](https://github.com/nikvas0))
+-   Keep ordinary, `DEFAULT`, `MATERIALIZED` and `ALIAS` columns in a single list (fixes issue [#2867](https://github.com/ClickHouse/ClickHouse/issues/2867)). [#4707](https://github.com/ClickHouse/ClickHouse/pull/4707) ([Alex Zatelepin](https://github.com/ztlpn))
+
+#### Bug Fix {#bug-fix-26}
+
+-   Avoid `std::terminate` in case of memory allocation failure. Now `std::bad_alloc` exception is thrown as expected. [#4665](https://github.com/ClickHouse/ClickHouse/pull/4665) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixes capnproto reading from buffer. Sometimes files wasn’t loaded successfully by HTTP. [#4674](https://github.com/ClickHouse/ClickHouse/pull/4674) ([Vladislav](https://github.com/smirnov-vs))
+-   Fix error `Unknown log entry type: 0` after `OPTIMIZE TABLE FINAL` query. [#4683](https://github.com/ClickHouse/ClickHouse/pull/4683) ([Amos Bird](https://github.com/amosbird))
+-   Wrong arguments to `hasAny` or `hasAll` functions may lead to segfault. [#4698](https://github.com/ClickHouse/ClickHouse/pull/4698) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Deadlock may happen while executing `DROP DATABASE dictionary` query. [#4701](https://github.com/ClickHouse/ClickHouse/pull/4701) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix undefined behavior in `median` and `quantile` functions. [#4702](https://github.com/ClickHouse/ClickHouse/pull/4702) ([hcz](https://github.com/hczhcz))
+-   Fix compression level detection when `network_compression_method` in lowercase. Broken in v19.1. [#4706](https://github.com/ClickHouse/ClickHouse/pull/4706) ([proller](https://github.com/proller))
+-   Fixed ignorance of `<timezone>UTC</timezone>` setting (fixes issue [#4658](https://github.com/ClickHouse/ClickHouse/issues/4658)). [#4718](https://github.com/ClickHouse/ClickHouse/pull/4718) ([proller](https://github.com/proller))
+-   Fix `histogram` function behaviour with `Distributed` tables. [#4741](https://github.com/ClickHouse/ClickHouse/pull/4741) ([olegkv](https://github.com/olegkv))
+-   Fixed tsan report `destroy of a locked mutex`. [#4742](https://github.com/ClickHouse/ClickHouse/pull/4742) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed TSan report on shutdown due to race condition in system logs usage. Fixed potential use-after-free on shutdown when part_log is enabled. [#4758](https://github.com/ClickHouse/ClickHouse/pull/4758) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix recheck parts in `ReplicatedMergeTreeAlterThread` in case of error. [#4772](https://github.com/ClickHouse/ClickHouse/pull/4772) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Arithmetic operations on intermediate aggregate function states were not working for constant arguments (such as subquery results). [#4776](https://github.com/ClickHouse/ClickHouse/pull/4776) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Always backquote column names in metadata. Otherwise it’s impossible to create a table with column named `index` (server won’t restart due to malformed `ATTACH` query in metadata). [#4782](https://github.com/ClickHouse/ClickHouse/pull/4782) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix crash in `ALTER ... MODIFY ORDER BY` on `Distributed` table. [#4790](https://github.com/ClickHouse/ClickHouse/pull/4790) ([TCeason](https://github.com/TCeason))
+-   Fix segfault in `JOIN ON` with enabled `enable_optimize_predicate_expression`. [#4794](https://github.com/ClickHouse/ClickHouse/pull/4794) ([Winter Zhang](https://github.com/zhang2014))
+-   Fix bug with adding an extraneous row after consuming a protobuf message from Kafka. [#4808](https://github.com/ClickHouse/ClickHouse/pull/4808) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fix crash of `JOIN` on not-nullable vs nullable column. Fix `NULLs` in right keys in `ANY JOIN` + `join_use_nulls`. [#4815](https://github.com/ClickHouse/ClickHouse/pull/4815) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix segmentation fault in `clickhouse-copier`. [#4835](https://github.com/ClickHouse/ClickHouse/pull/4835) ([proller](https://github.com/proller))
+-   Fixed race condition in `SELECT` from `system.tables` if the table is renamed or altered concurrently. [#4836](https://github.com/ClickHouse/ClickHouse/pull/4836) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed data race when fetching data part that is already obsolete. [#4839](https://github.com/ClickHouse/ClickHouse/pull/4839) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed rare data race that can happen during `RENAME` table of MergeTree family. [#4844](https://github.com/ClickHouse/ClickHouse/pull/4844) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed segmentation fault in function `arrayIntersect`. Segmentation fault could happen if function was called with mixed constant and ordinary arguments. [#4847](https://github.com/ClickHouse/ClickHouse/pull/4847) ([Lixiang Qian](https://github.com/fancyqlx))
+-   Fixed reading from `Array(LowCardinality)` column in rare case when column contained a long sequence of empty arrays. [#4850](https://github.com/ClickHouse/ClickHouse/pull/4850) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix crash in `FULL/RIGHT JOIN` when we joining on nullable vs not nullable. [#4855](https://github.com/ClickHouse/ClickHouse/pull/4855) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix `No message received` exception while fetching parts between replicas. [#4856](https://github.com/ClickHouse/ClickHouse/pull/4856) ([alesapin](https://github.com/alesapin))
+-   Fixed `arrayIntersect` function wrong result in case of several repeated values in single array. [#4871](https://github.com/ClickHouse/ClickHouse/pull/4871) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix a race condition during concurrent `ALTER COLUMN` queries that could lead to a server crash (fixes issue [#3421](https://github.com/ClickHouse/ClickHouse/issues/3421)). [#4592](https://github.com/ClickHouse/ClickHouse/pull/4592) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Fix incorrect result in `FULL/RIGHT JOIN` with const column. [#4723](https://github.com/ClickHouse/ClickHouse/pull/4723) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix duplicates in `GLOBAL JOIN` with asterisk. [#4705](https://github.com/ClickHouse/ClickHouse/pull/4705) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix parameter deduction in `ALTER MODIFY` of column `CODEC` when column type is not specified. [#4883](https://github.com/ClickHouse/ClickHouse/pull/4883) ([alesapin](https://github.com/alesapin))
+-   Functions `cutQueryStringAndFragment()` and `queryStringAndFragment()` now works correctly when `URL` contains a fragment and no query. [#4894](https://github.com/ClickHouse/ClickHouse/pull/4894) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fix rare bug when setting `min_bytes_to_use_direct_io` is greater than zero, which occures when thread have to seek backward in column file. [#4897](https://github.com/ClickHouse/ClickHouse/pull/4897) ([alesapin](https://github.com/alesapin))
+-   Fix wrong argument types for aggregate functions with `LowCardinality` arguments (fixes issue [#4919](https://github.com/ClickHouse/ClickHouse/issues/4919)). [#4922](https://github.com/ClickHouse/ClickHouse/pull/4922) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix wrong name qualification in `GLOBAL JOIN`. [#4969](https://github.com/ClickHouse/ClickHouse/pull/4969) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix function `toISOWeek` result for year 1970. [#4988](https://github.com/ClickHouse/ClickHouse/pull/4988) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix `DROP`, `TRUNCATE` and `OPTIMIZE` queries duplication, when executed on `ON CLUSTER` for `ReplicatedMergeTree*` tables family. [#4991](https://github.com/ClickHouse/ClickHouse/pull/4991) ([alesapin](https://github.com/alesapin))
+
+#### Backward Incompatible Change {#backward-incompatible-change-8}
+
+-   Rename setting `insert_sample_with_metadata` to setting `input_format_defaults_for_omitted_fields`. [#4771](https://github.com/ClickHouse/ClickHouse/pull/4771) ([Artem Zuikov](https://github.com/4ertus2))
+-   Added setting `max_partitions_per_insert_block` (with value 100 by default). If inserted block contains larger number of partitions, an exception is thrown. Set it to 0 if you want to remove the limit (not recommended). [#4845](https://github.com/ClickHouse/ClickHouse/pull/4845) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Multi-search functions were renamed (`multiPosition` to `multiSearchAllPositions`, `multiSearch` to `multiSearchAny`, `firstMatch` to `multiSearchFirstIndex`). [#4780](https://github.com/ClickHouse/ClickHouse/pull/4780) ([Danila Kutenin](https://github.com/danlark1))
+
+#### Performance Improvement {#performance-improvement-6}
+
+-   Optimize Volnitsky searcher by inlining, giving about 5-10% search improvement for queries with many needles or many similar bigrams. [#4862](https://github.com/ClickHouse/ClickHouse/pull/4862) ([Danila Kutenin](https://github.com/danlark1))
+-   Fix performance issue when setting `use_uncompressed_cache` is greater than zero, which appeared when all read data contained in cache. [#4913](https://github.com/ClickHouse/ClickHouse/pull/4913) ([alesapin](https://github.com/alesapin))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-10}
+
+-   Hardening debug build: more granular memory mappings and ASLR; add memory protection for mark cache and index. This allows to find more memory stomping bugs in case when ASan and MSan cannot do it. [#4632](https://github.com/ClickHouse/ClickHouse/pull/4632) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add support for cmake variables `ENABLE_PROTOBUF`, `ENABLE_PARQUET` and `ENABLE_BROTLI` which allows to enable/disable the above features (same as we can do for librdkafka, mysql, etc). [#4669](https://github.com/ClickHouse/ClickHouse/pull/4669) ([Silviu Caragea](https://github.com/silviucpp))
+-   Add ability to print process list and stacktraces of all threads if some queries are hung after test run. [#4675](https://github.com/ClickHouse/ClickHouse/pull/4675) ([alesapin](https://github.com/alesapin))
+-   Add retries on `Connection loss` error in `clickhouse-test`. [#4682](https://github.com/ClickHouse/ClickHouse/pull/4682) ([alesapin](https://github.com/alesapin))
+-   Add freebsd build with vagrant and build with thread sanitizer to packager script. [#4712](https://github.com/ClickHouse/ClickHouse/pull/4712) [#4748](https://github.com/ClickHouse/ClickHouse/pull/4748) ([alesapin](https://github.com/alesapin))
+-   Now user asked for password for user `'default'` during installation. [#4725](https://github.com/ClickHouse/ClickHouse/pull/4725) ([proller](https://github.com/proller))
+-   Suppress warning in `rdkafka` library. [#4740](https://github.com/ClickHouse/ClickHouse/pull/4740) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Allow ability to build without ssl. [#4750](https://github.com/ClickHouse/ClickHouse/pull/4750) ([proller](https://github.com/proller))
+-   Add a way to launch clickhouse-server image from a custom user. [#4753](https://github.com/ClickHouse/ClickHouse/pull/4753) ([Mikhail f. Shiryaev](https://github.com/Felixoid))
+-   Upgrade contrib boost to 1.69. [#4793](https://github.com/ClickHouse/ClickHouse/pull/4793) ([proller](https://github.com/proller))
+-   Disable usage of `mremap` when compiled with Thread Sanitizer. Surprisingly enough, TSan does not intercept `mremap` (though it does intercept `mmap`, `munmap`) that leads to false positives. Fixed TSan report in stateful tests. [#4859](https://github.com/ClickHouse/ClickHouse/pull/4859) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add test checking using format schema via HTTP interface. [#4864](https://github.com/ClickHouse/ClickHouse/pull/4864) ([Vitaly Baranov](https://github.com/vitlibar))
+
+## ClickHouse Release 19.4 {#clickhouse-release-19-4}
+
+### ClickHouse Release 19.4.4.33, 2019-04-17 {#clickhouse-release-19-4-4-33-2019-04-17}
+
+#### Bug Fixes {#bug-fixes-7}
+
+-   Avoid `std::terminate` in case of memory allocation failure. Now `std::bad_alloc` exception is thrown as expected. [#4665](https://github.com/ClickHouse/ClickHouse/pull/4665) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixes capnproto reading from buffer. Sometimes files wasn’t loaded successfully by HTTP. [#4674](https://github.com/ClickHouse/ClickHouse/pull/4674) ([Vladislav](https://github.com/smirnov-vs))
+-   Fix error `Unknown log entry type: 0` after `OPTIMIZE TABLE FINAL` query. [#4683](https://github.com/ClickHouse/ClickHouse/pull/4683) ([Amos Bird](https://github.com/amosbird))
+-   Wrong arguments to `hasAny` or `hasAll` functions may lead to segfault. [#4698](https://github.com/ClickHouse/ClickHouse/pull/4698) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Deadlock may happen while executing `DROP DATABASE dictionary` query. [#4701](https://github.com/ClickHouse/ClickHouse/pull/4701) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix undefined behavior in `median` and `quantile` functions. [#4702](https://github.com/ClickHouse/ClickHouse/pull/4702) ([hcz](https://github.com/hczhcz))
+-   Fix compression level detection when `network_compression_method` in lowercase. Broken in v19.1. [#4706](https://github.com/ClickHouse/ClickHouse/pull/4706) ([proller](https://github.com/proller))
+-   Fixed ignorance of `<timezone>UTC</timezone>` setting (fixes issue [#4658](https://github.com/ClickHouse/ClickHouse/issues/4658)). [#4718](https://github.com/ClickHouse/ClickHouse/pull/4718) ([proller](https://github.com/proller))
+-   Fix `histogram` function behaviour with `Distributed` tables. [#4741](https://github.com/ClickHouse/ClickHouse/pull/4741) ([olegkv](https://github.com/olegkv))
+-   Fixed tsan report `destroy of a locked mutex`. [#4742](https://github.com/ClickHouse/ClickHouse/pull/4742) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed TSan report on shutdown due to race condition in system logs usage. Fixed potential use-after-free on shutdown when part_log is enabled. [#4758](https://github.com/ClickHouse/ClickHouse/pull/4758) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix recheck parts in `ReplicatedMergeTreeAlterThread` in case of error. [#4772](https://github.com/ClickHouse/ClickHouse/pull/4772) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Arithmetic operations on intermediate aggregate function states were not working for constant arguments (such as subquery results). [#4776](https://github.com/ClickHouse/ClickHouse/pull/4776) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Always backquote column names in metadata. Otherwise it’s impossible to create a table with column named `index` (server won’t restart due to malformed `ATTACH` query in metadata). [#4782](https://github.com/ClickHouse/ClickHouse/pull/4782) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix crash in `ALTER ... MODIFY ORDER BY` on `Distributed` table. [#4790](https://github.com/ClickHouse/ClickHouse/pull/4790) ([TCeason](https://github.com/TCeason))
+-   Fix segfault in `JOIN ON` with enabled `enable_optimize_predicate_expression`. [#4794](https://github.com/ClickHouse/ClickHouse/pull/4794) ([Winter Zhang](https://github.com/zhang2014))
+-   Fix bug with adding an extraneous row after consuming a protobuf message from Kafka. [#4808](https://github.com/ClickHouse/ClickHouse/pull/4808) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fix segmentation fault in `clickhouse-copier`. [#4835](https://github.com/ClickHouse/ClickHouse/pull/4835) ([proller](https://github.com/proller))
+-   Fixed race condition in `SELECT` from `system.tables` if the table is renamed or altered concurrently. [#4836](https://github.com/ClickHouse/ClickHouse/pull/4836) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed data race when fetching data part that is already obsolete. [#4839](https://github.com/ClickHouse/ClickHouse/pull/4839) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed rare data race that can happen during `RENAME` table of MergeTree family. [#4844](https://github.com/ClickHouse/ClickHouse/pull/4844) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed segmentation fault in function `arrayIntersect`. Segmentation fault could happen if function was called with mixed constant and ordinary arguments. [#4847](https://github.com/ClickHouse/ClickHouse/pull/4847) ([Lixiang Qian](https://github.com/fancyqlx))
+-   Fixed reading from `Array(LowCardinality)` column in rare case when column contained a long sequence of empty arrays. [#4850](https://github.com/ClickHouse/ClickHouse/pull/4850) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix `No message received` exception while fetching parts between replicas. [#4856](https://github.com/ClickHouse/ClickHouse/pull/4856) ([alesapin](https://github.com/alesapin))
+-   Fixed `arrayIntersect` function wrong result in case of several repeated values in single array. [#4871](https://github.com/ClickHouse/ClickHouse/pull/4871) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix a race condition during concurrent `ALTER COLUMN` queries that could lead to a server crash (fixes issue [#3421](https://github.com/ClickHouse/ClickHouse/issues/3421)). [#4592](https://github.com/ClickHouse/ClickHouse/pull/4592) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Fix parameter deduction in `ALTER MODIFY` of column `CODEC` when column type is not specified. [#4883](https://github.com/ClickHouse/ClickHouse/pull/4883) ([alesapin](https://github.com/alesapin))
+-   Functions `cutQueryStringAndFragment()` and `queryStringAndFragment()` now works correctly when `URL` contains a fragment and no query. [#4894](https://github.com/ClickHouse/ClickHouse/pull/4894) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Fix rare bug when setting `min_bytes_to_use_direct_io` is greater than zero, which occures when thread have to seek backward in column file. [#4897](https://github.com/ClickHouse/ClickHouse/pull/4897) ([alesapin](https://github.com/alesapin))
+-   Fix wrong argument types for aggregate functions with `LowCardinality` arguments (fixes issue [#4919](https://github.com/ClickHouse/ClickHouse/issues/4919)). [#4922](https://github.com/ClickHouse/ClickHouse/pull/4922) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fix function `toISOWeek` result for year 1970. [#4988](https://github.com/ClickHouse/ClickHouse/pull/4988) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix `DROP`, `TRUNCATE` and `OPTIMIZE` queries duplication, when executed on `ON CLUSTER` for `ReplicatedMergeTree*` tables family. [#4991](https://github.com/ClickHouse/ClickHouse/pull/4991) ([alesapin](https://github.com/alesapin))
+
+#### Improvements {#improvements-2}
+
+-   Keep ordinary, `DEFAULT`, `MATERIALIZED` and `ALIAS` columns in a single list (fixes issue [#2867](https://github.com/ClickHouse/ClickHouse/issues/2867)). [#4707](https://github.com/ClickHouse/ClickHouse/pull/4707) ([Alex Zatelepin](https://github.com/ztlpn))
+
+### ClickHouse Release 19.4.3.11, 2019-04-02 {#clickhouse-release-19-4-3-11-2019-04-02}
+
+#### Bug Fixes {#bug-fixes-8}
+
+-   Fix crash in `FULL/RIGHT JOIN` when we joining on nullable vs not nullable. [#4855](https://github.com/ClickHouse/ClickHouse/pull/4855) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix segmentation fault in `clickhouse-copier`. [#4835](https://github.com/ClickHouse/ClickHouse/pull/4835) ([proller](https://github.com/proller))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-11}
+
+-   Add a way to launch clickhouse-server image from a custom user. [#4753](https://github.com/ClickHouse/ClickHouse/pull/4753) ([Mikhail f. Shiryaev](https://github.com/Felixoid))
+
+### ClickHouse Release 19.4.2.7, 2019-03-30 {#clickhouse-release-19-4-2-7-2019-03-30}
+
+#### Bug Fixes {#bug-fixes-9}
+
+-   Fixed reading from `Array(LowCardinality)` column in rare case when column contained a long sequence of empty arrays. [#4850](https://github.com/ClickHouse/ClickHouse/pull/4850) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+
+### ClickHouse Release 19.4.1.3, 2019-03-19 {#clickhouse-release-19-4-1-3-2019-03-19}
+
+#### Bug Fixes {#bug-fixes-10}
+
+-   Fixed remote queries which contain both `LIMIT BY` and `LIMIT`. Previously, if `LIMIT BY` and `LIMIT` were used for remote query, `LIMIT` could happen before `LIMIT BY`, which led to too filtered result. [#4708](https://github.com/ClickHouse/ClickHouse/pull/4708) ([Constantin S. Pan](https://github.com/kvap))
+
+### ClickHouse Release 19.4.0.49, 2019-03-09 {#clickhouse-release-19-4-0-49-2019-03-09}
+
+#### New Features {#new-features-5}
+
+-   Added full support for `Protobuf` format (input and output, nested data structures). [#4174](https://github.com/ClickHouse/ClickHouse/pull/4174) [#4493](https://github.com/ClickHouse/ClickHouse/pull/4493) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Added bitmap functions with Roaring Bitmaps. [#4207](https://github.com/ClickHouse/ClickHouse/pull/4207) ([Andy Yang](https://github.com/andyyzh)) [#4568](https://github.com/ClickHouse/ClickHouse/pull/4568) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Parquet format support. [#4448](https://github.com/ClickHouse/ClickHouse/pull/4448) ([proller](https://github.com/proller))
+-   N-gram distance was added for fuzzy string comparison. It is similar to q-gram metrics in R language. [#4466](https://github.com/ClickHouse/ClickHouse/pull/4466) ([Danila Kutenin](https://github.com/danlark1))
+-   Combine rules for graphite rollup from dedicated aggregation and retention patterns. [#4426](https://github.com/ClickHouse/ClickHouse/pull/4426) ([Mikhail f. Shiryaev](https://github.com/Felixoid))
+-   Added `max_execution_speed` and `max_execution_speed_bytes` to limit resource usage. Added `min_execution_speed_bytes` setting to complement the `min_execution_speed`. [#4430](https://github.com/ClickHouse/ClickHouse/pull/4430) ([Winter Zhang](https://github.com/zhang2014))
+-   Implemented function `flatten`. [#4555](https://github.com/ClickHouse/ClickHouse/pull/4555) [#4409](https://github.com/ClickHouse/ClickHouse/pull/4409) ([alexey-milovidov](https://github.com/alexey-milovidov), [kzon](https://github.com/kzon))
+-   Added functions `arrayEnumerateDenseRanked` and `arrayEnumerateUniqRanked` (it’s like `arrayEnumerateUniq` but allows to fine tune array depth to look inside multidimensional arrays). [#4475](https://github.com/ClickHouse/ClickHouse/pull/4475) ([proller](https://github.com/proller)) [#4601](https://github.com/ClickHouse/ClickHouse/pull/4601) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Multiple JOINS with some restrictions: no asterisks, no complex aliases in ON/WHERE/GROUP BY/… [#4462](https://github.com/ClickHouse/ClickHouse/pull/4462) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Bug Fixes {#bug-fixes-11}
+
+-   This release also contains all bug fixes from 19.3 and 19.1.
+-   Fixed bug in data skipping indices: order of granules after INSERT was incorrect. [#4407](https://github.com/ClickHouse/ClickHouse/pull/4407) ([Nikita Vasilev](https://github.com/nikvas0))
+-   Fixed `set` index for `Nullable` and `LowCardinality` columns. Before it, `set` index with `Nullable` or `LowCardinality` column led to error `Data type must be deserialized with multiple streams` while selecting. [#4594](https://github.com/ClickHouse/ClickHouse/pull/4594) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Correctly set update_time on full `executable` dictionary update. [#4551](https://github.com/ClickHouse/ClickHouse/pull/4551) ([Tema Novikov](https://github.com/temoon))
+-   Fix broken progress bar in 19.3. [#4627](https://github.com/ClickHouse/ClickHouse/pull/4627) ([filimonov](https://github.com/filimonov))
+-   Fixed inconsistent values of MemoryTracker when memory region was shrinked, in certain cases. [#4619](https://github.com/ClickHouse/ClickHouse/pull/4619) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed undefined behaviour in ThreadPool. [#4612](https://github.com/ClickHouse/ClickHouse/pull/4612) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed a very rare crash with the message `mutex lock failed: Invalid argument` that could happen when a MergeTree table was dropped concurrently with a SELECT. [#4608](https://github.com/ClickHouse/ClickHouse/pull/4608) ([Alex Zatelepin](https://github.com/ztlpn))
+-   ODBC driver compatibility with `LowCardinality` data type. [#4381](https://github.com/ClickHouse/ClickHouse/pull/4381) ([proller](https://github.com/proller))
+-   FreeBSD: Fixup for `AIOcontextPool: Found io_event with unknown id 0` error. [#4438](https://github.com/ClickHouse/ClickHouse/pull/4438) ([urgordeadbeef](https://github.com/urgordeadbeef))
+-   `system.part_log` table was created regardless to configuration. [#4483](https://github.com/ClickHouse/ClickHouse/pull/4483) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix undefined behaviour in `dictIsIn` function for cache dictionaries. [#4515](https://github.com/ClickHouse/ClickHouse/pull/4515) ([alesapin](https://github.com/alesapin))
+-   Fixed a deadlock when a SELECT query locks the same table multiple times (e.g. from different threads or when executing multiple subqueries) and there is a concurrent DDL query. [#4535](https://github.com/ClickHouse/ClickHouse/pull/4535) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Disable compile_expressions by default until we get own `llvm` contrib and can test it with `clang` and `asan`. [#4579](https://github.com/ClickHouse/ClickHouse/pull/4579) ([alesapin](https://github.com/alesapin))
+-   Prevent `std::terminate` when `invalidate_query` for `clickhouse` external dictionary source has returned wrong resultset (empty or more than one row or more than one column). Fixed issue when the `invalidate_query` was performed every five seconds regardless to the `lifetime`. [#4583](https://github.com/ClickHouse/ClickHouse/pull/4583) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Avoid deadlock when the `invalidate_query` for a dictionary with `clickhouse` source was involving `system.dictionaries` table or `Dictionaries` database (rare case). [#4599](https://github.com/ClickHouse/ClickHouse/pull/4599) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixes for CROSS JOIN with empty WHERE. [#4598](https://github.com/ClickHouse/ClickHouse/pull/4598) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed segfault in function “replicate” when constant argument is passed. [#4603](https://github.com/ClickHouse/ClickHouse/pull/4603) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix lambda function with predicate optimizer. [#4408](https://github.com/ClickHouse/ClickHouse/pull/4408) ([Winter Zhang](https://github.com/zhang2014))
+-   Multiple JOINs multiple fixes. [#4595](https://github.com/ClickHouse/ClickHouse/pull/4595) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Improvements {#improvements-3}
+
+-   Support aliases in JOIN ON section for right table columns. [#4412](https://github.com/ClickHouse/ClickHouse/pull/4412) ([Artem Zuikov](https://github.com/4ertus2))
+-   Result of multiple JOINs need correct result names to be used in subselects. Replace flat aliases with source names in result. [#4474](https://github.com/ClickHouse/ClickHouse/pull/4474) ([Artem Zuikov](https://github.com/4ertus2))
+-   Improve push-down logic for joined statements. [#4387](https://github.com/ClickHouse/ClickHouse/pull/4387) ([Ivan](https://github.com/abyss7))
+
+#### Performance Improvements {#performance-improvements-3}
+
+-   Improved heuristics of “move to PREWHERE” optimization. [#4405](https://github.com/ClickHouse/ClickHouse/pull/4405) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Use proper lookup tables that uses HashTable’s API for 8-bit and 16-bit keys. [#4536](https://github.com/ClickHouse/ClickHouse/pull/4536) ([Amos Bird](https://github.com/amosbird))
+-   Improved performance of string comparison. [#4564](https://github.com/ClickHouse/ClickHouse/pull/4564) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Cleanup distributed DDL queue in a separate thread so that it does not slow down the main loop that processes distributed DDL tasks. [#4502](https://github.com/ClickHouse/ClickHouse/pull/4502) ([Alex Zatelepin](https://github.com/ztlpn))
+-   When `min_bytes_to_use_direct_io` is set to 1, not every file was opened with O_DIRECT mode because the data size to read was sometimes underestimated by the size of one compressed block. [#4526](https://github.com/ClickHouse/ClickHouse/pull/4526) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-12}
+
+-   Added support for clang-9 [#4604](https://github.com/ClickHouse/ClickHouse/pull/4604) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix wrong `__asm__` instructions (again) [#4621](https://github.com/ClickHouse/ClickHouse/pull/4621) ([Konstantin Podshumok](https://github.com/podshumok))
+-   Add ability to specify settings for `clickhouse-performance-test` from command line. [#4437](https://github.com/ClickHouse/ClickHouse/pull/4437) ([alesapin](https://github.com/alesapin))
+-   Add dictionaries tests to integration tests. [#4477](https://github.com/ClickHouse/ClickHouse/pull/4477) ([alesapin](https://github.com/alesapin))
+-   Added queries from the benchmark on the website to automated performance tests. [#4496](https://github.com/ClickHouse/ClickHouse/pull/4496) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   `xxhash.h` does not exist in external lz4 because it is an implementation detail and its symbols are namespaced with `XXH_NAMESPACE` macro. When lz4 is external, xxHash has to be external too, and the dependents have to link to it. [#4495](https://github.com/ClickHouse/ClickHouse/pull/4495) ([Orivej Desh](https://github.com/orivej))
+-   Fixed a case when `quantileTiming` aggregate function can be called with negative or floating point argument (this fixes fuzz test with undefined behaviour sanitizer). [#4506](https://github.com/ClickHouse/ClickHouse/pull/4506) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Spelling error correction. [#4531](https://github.com/ClickHouse/ClickHouse/pull/4531) ([sdk2](https://github.com/sdk2))
+-   Fix compilation on Mac. [#4371](https://github.com/ClickHouse/ClickHouse/pull/4371) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Build fixes for FreeBSD and various unusual build configurations. [#4444](https://github.com/ClickHouse/ClickHouse/pull/4444) ([proller](https://github.com/proller))
+
+## ClickHouse Release 19.3 {#clickhouse-release-19-3}
+
+### ClickHouse Release 19.3.9.1, 2019-04-02 {#clickhouse-release-19-3-9-1-2019-04-02}
+
+#### Bug Fixes {#bug-fixes-12}
+
+-   Fix crash in `FULL/RIGHT JOIN` when we joining on nullable vs not nullable. [#4855](https://github.com/ClickHouse/ClickHouse/pull/4855) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fix segmentation fault in `clickhouse-copier`. [#4835](https://github.com/ClickHouse/ClickHouse/pull/4835) ([proller](https://github.com/proller))
+-   Fixed reading from `Array(LowCardinality)` column in rare case when column contained a long sequence of empty arrays. [#4850](https://github.com/ClickHouse/ClickHouse/pull/4850) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+
+#### Build/Testing/Packaging Improvement {#buildtestingpackaging-improvement-13}
+
+-   Add a way to launch clickhouse-server image from a custom user [#4753](https://github.com/ClickHouse/ClickHouse/pull/4753) ([Mikhail f. Shiryaev](https://github.com/Felixoid))
+
+### ClickHouse Release 19.3.7, 2019-03-12 {#clickhouse-release-19-3-7-2019-03-12}
+
+#### Bug Fixes {#bug-fixes-13}
+
+-   Fixed error in #3920. This error manifests itself as random cache corruption (messages `Unknown codec family code`, `Cannot seek through file`) and segfaults. This bug first appeared in version 19.1 and is present in versions up to 19.1.10 and 19.3.6. [#4623](https://github.com/ClickHouse/ClickHouse/pull/4623) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.3.6, 2019-03-02 {#clickhouse-release-19-3-6-2019-03-02}
+
+#### Bug Fixes {#bug-fixes-14}
+
+-   When there are more than 1000 threads in a thread pool, `std::terminate` may happen on thread exit. [Azat Khuzhin](https://github.com/azat) [#4485](https://github.com/ClickHouse/ClickHouse/pull/4485) [#4505](https://github.com/ClickHouse/ClickHouse/pull/4505) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Now it’s possible to create `ReplicatedMergeTree*` tables with comments on columns without defaults and tables with columns codecs without comments and defaults. Also fix comparison of codecs. [#4523](https://github.com/ClickHouse/ClickHouse/pull/4523) ([alesapin](https://github.com/alesapin))
+-   Fixed crash on JOIN with array or tuple. [#4552](https://github.com/ClickHouse/ClickHouse/pull/4552) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed crash in clickhouse-copier with the message `ThreadStatus not created`. [#4540](https://github.com/ClickHouse/ClickHouse/pull/4540) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed hangup on server shutdown if distributed DDLs were used. [#4472](https://github.com/ClickHouse/ClickHouse/pull/4472) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Incorrect column numbers were printed in error message about text format parsing for columns with number greater than 10. [#4484](https://github.com/ClickHouse/ClickHouse/pull/4484) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Build/Testing/Packaging Improvements {#buildtestingpackaging-improvements-3}
+
+-   Fixed build with AVX enabled. [#4527](https://github.com/ClickHouse/ClickHouse/pull/4527) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Enable extended accounting and IO accounting based on good known version instead of kernel under which it is compiled. [#4541](https://github.com/ClickHouse/ClickHouse/pull/4541) ([nvartolomei](https://github.com/nvartolomei))
+-   Allow to skip setting of core_dump.size_limit, warning instead of throw if limit set fail. [#4473](https://github.com/ClickHouse/ClickHouse/pull/4473) ([proller](https://github.com/proller))
+-   Removed the `inline` tags of `void readBinary(...)` in `Field.cpp`. Also merged redundant `namespace DB` blocks. [#4530](https://github.com/ClickHouse/ClickHouse/pull/4530) ([hcz](https://github.com/hczhcz))
+
+### ClickHouse Release 19.3.5, 2019-02-21 {#clickhouse-release-19-3-5-2019-02-21}
+
+#### Bug Fixes {#bug-fixes-15}
+
+-   Fixed bug with large http insert queries processing. [#4454](https://github.com/ClickHouse/ClickHouse/pull/4454) ([alesapin](https://github.com/alesapin))
+-   Fixed backward incompatibility with old versions due to wrong implementation of `send_logs_level` setting. [#4445](https://github.com/ClickHouse/ClickHouse/pull/4445) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed backward incompatibility of table function `remote` introduced with column comments. [#4446](https://github.com/ClickHouse/ClickHouse/pull/4446) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.3.4, 2019-02-16 {#clickhouse-release-19-3-4-2019-02-16}
+
+#### Improvements {#improvements-4}
+
+-   Table index size is not accounted for memory limits when doing `ATTACH TABLE` query. Avoided the possibility that a table cannot be attached after being detached. [#4396](https://github.com/ClickHouse/ClickHouse/pull/4396) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Slightly raised up the limit on max string and array size received from ZooKeeper. It allows to continue to work with increased size of `CLIENT_JVMFLAGS=-Djute.maxbuffer=...` on ZooKeeper. [#4398](https://github.com/ClickHouse/ClickHouse/pull/4398) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Allow to repair abandoned replica even if it already has huge number of nodes in its queue. [#4399](https://github.com/ClickHouse/ClickHouse/pull/4399) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Add one required argument to `SET` index (max stored rows number). [#4386](https://github.com/ClickHouse/ClickHouse/pull/4386) ([Nikita Vasilev](https://github.com/nikvas0))
+
+#### Bug Fixes {#bug-fixes-16}
+
+-   Fixed `WITH ROLLUP` result for group by single `LowCardinality` key. [#4384](https://github.com/ClickHouse/ClickHouse/pull/4384) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Fixed bug in the set index (dropping a granule if it contains more than `max_rows` rows). [#4386](https://github.com/ClickHouse/ClickHouse/pull/4386) ([Nikita Vasilev](https://github.com/nikvas0))
+-   A lot of FreeBSD build fixes. [#4397](https://github.com/ClickHouse/ClickHouse/pull/4397) ([proller](https://github.com/proller))
+-   Fixed aliases substitution in queries with subquery containing same alias (issue [#4110](https://github.com/ClickHouse/ClickHouse/issues/4110)). [#4351](https://github.com/ClickHouse/ClickHouse/pull/4351) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Build/Testing/Packaging Improvements {#buildtestingpackaging-improvements-4}
+
+-   Add ability to run `clickhouse-server` for stateless tests in docker image. [#4347](https://github.com/ClickHouse/ClickHouse/pull/4347) ([Vasily Nemkov](https://github.com/Enmk))
+
+### ClickHouse Release 19.3.3, 2019-02-13 {#clickhouse-release-19-3-3-2019-02-13}
+
+#### New Features {#new-features-6}
+
+-   Added the `KILL MUTATION` statement that allows removing mutations that are for some reasons stuck. Added `latest_failed_part`, `latest_fail_time`, `latest_fail_reason` fields to the `system.mutations` table for easier troubleshooting. [#4287](https://github.com/ClickHouse/ClickHouse/pull/4287) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Added aggregate function `entropy` which computes Shannon entropy. [#4238](https://github.com/ClickHouse/ClickHouse/pull/4238) ([Quid37](https://github.com/Quid37))
+-   Added ability to send queries `INSERT INTO tbl VALUES (....` to server without splitting on `query` and `data` parts. [#4301](https://github.com/ClickHouse/ClickHouse/pull/4301) ([alesapin](https://github.com/alesapin))
+-   Generic implementation of `arrayWithConstant` function was added. [#4322](https://github.com/ClickHouse/ClickHouse/pull/4322) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Implemented `NOT BETWEEN` comparison operator. [#4228](https://github.com/ClickHouse/ClickHouse/pull/4228) ([Dmitry Naumov](https://github.com/nezed))
+-   Implement `sumMapFiltered` in order to be able to limit the number of keys for which values will be summed by `sumMap`. [#4129](https://github.com/ClickHouse/ClickHouse/pull/4129) ([Léo Ercolanelli](https://github.com/ercolanelli-leo))
+-   Added support of `Nullable` types in `mysql` table function. [#4198](https://github.com/ClickHouse/ClickHouse/pull/4198) ([Emmanuel Donin de Rosière](https://github.com/edonin))
+-   Support for arbitrary constant expressions in `LIMIT` clause. [#4246](https://github.com/ClickHouse/ClickHouse/pull/4246) ([k3box](https://github.com/k3box))
+-   Added `topKWeighted` aggregate function that takes additional argument with (unsigned integer) weight. [#4245](https://github.com/ClickHouse/ClickHouse/pull/4245) ([Andrew Golman](https://github.com/andrewgolman))
+-   `StorageJoin` now supports `join_any_take_last_row` setting that allows overwriting existing values of the same key. [#3973](https://github.com/ClickHouse/ClickHouse/pull/3973) ([Amos Bird](https://github.com/amosbird)
+-   Added function `toStartOfInterval`. [#4304](https://github.com/ClickHouse/ClickHouse/pull/4304) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Added `RowBinaryWithNamesAndTypes` format. [#4200](https://github.com/ClickHouse/ClickHouse/pull/4200) ([Oleg V. Kozlyuk](https://github.com/DarkWanderer))
+-   Added `IPv4` and `IPv6` data types. More effective implementations of `IPv*` functions. [#3669](https://github.com/ClickHouse/ClickHouse/pull/3669) ([Vasily Nemkov](https://github.com/Enmk))
+-   Added function `toStartOfTenMinutes()`. [#4298](https://github.com/ClickHouse/ClickHouse/pull/4298) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Added `Protobuf` output format. [#4005](https://github.com/ClickHouse/ClickHouse/pull/4005) [#4158](https://github.com/ClickHouse/ClickHouse/pull/4158) ([Vitaly Baranov](https://github.com/vitlibar))
+-   Added brotli support for HTTP interface for data import (INSERTs). [#4235](https://github.com/ClickHouse/ClickHouse/pull/4235) ([Mikhail](https://github.com/fandyushin))
+-   Added hints while user make typo in function name or type in command line client. [#4239](https://github.com/ClickHouse/ClickHouse/pull/4239) ([Danila Kutenin](https://github.com/danlark1))
+-   Added `Query-Id` to Server’s HTTP Response header. [#4231](https://github.com/ClickHouse/ClickHouse/pull/4231) ([Mikhail](https://github.com/fandyushin))
+
+#### Experimental Features {#experimental-features-2}
+
+-   Added `minmax` and `set` data skipping indices for MergeTree table engines family. [#4143](https://github.com/ClickHouse/ClickHouse/pull/4143) ([Nikita Vasilev](https://github.com/nikvas0))
+-   Added conversion of `CROSS JOIN` to `INNER JOIN` if possible. [#4221](https://github.com/ClickHouse/ClickHouse/pull/4221) [#4266](https://github.com/ClickHouse/ClickHouse/pull/4266) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Bug Fixes {#bug-fixes-17}
+
+-   Fixed `Not found column` for duplicate columns in `JOIN ON` section. [#4279](https://github.com/ClickHouse/ClickHouse/pull/4279) ([Artem Zuikov](https://github.com/4ertus2))
+-   Make `START REPLICATED SENDS` command start replicated sends. [#4229](https://github.com/ClickHouse/ClickHouse/pull/4229) ([nvartolomei](https://github.com/nvartolomei))
+-   Fixed aggregate functions execution with `Array(LowCardinality)` arguments. [#4055](https://github.com/ClickHouse/ClickHouse/pull/4055) ([KochetovNicolai](https://github.com/KochetovNicolai))
+-   Fixed wrong behaviour when doing `INSERT ... SELECT ... FROM file(...)` query and file has `CSVWithNames` or `TSVWIthNames` format and the first data row is missing. [#4297](https://github.com/ClickHouse/ClickHouse/pull/4297) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed crash on dictionary reload if dictionary not available. This bug was appeared in 19.1.6. [#4188](https://github.com/ClickHouse/ClickHouse/pull/4188) ([proller](https://github.com/proller))
+-   Fixed `ALL JOIN` with duplicates in right table. [#4184](https://github.com/ClickHouse/ClickHouse/pull/4184) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed segmentation fault with `use_uncompressed_cache=1` and exception with wrong uncompressed size. This bug was appeared in 19.1.6. [#4186](https://github.com/ClickHouse/ClickHouse/pull/4186) ([alesapin](https://github.com/alesapin))
+-   Fixed `compile_expressions` bug with comparison of big (more than int16) dates. [#4341](https://github.com/ClickHouse/ClickHouse/pull/4341) ([alesapin](https://github.com/alesapin))
+-   Fixed infinite loop when selecting from table function `numbers(0)`. [#4280](https://github.com/ClickHouse/ClickHouse/pull/4280) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Temporarily disable predicate optimization for `ORDER BY`. [#3890](https://github.com/ClickHouse/ClickHouse/pull/3890) ([Winter Zhang](https://github.com/zhang2014))
+-   Fixed `Illegal instruction` error when using base64 functions on old CPUs. This error has been reproduced only when ClickHouse was compiled with gcc-8. [#4275](https://github.com/ClickHouse/ClickHouse/pull/4275) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed `No message received` error when interacting with PostgreSQL ODBC Driver through TLS connection. Also fixes segfault when using MySQL ODBC Driver. [#4170](https://github.com/ClickHouse/ClickHouse/pull/4170) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed incorrect result when `Date` and `DateTime` arguments are used in branches of conditional operator (function `if`). Added generic case for function `if`. [#4243](https://github.com/ClickHouse/ClickHouse/pull/4243) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   ClickHouse dictionaries now load within `clickhouse` process. [#4166](https://github.com/ClickHouse/ClickHouse/pull/4166) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed deadlock when `SELECT` from a table with `File` engine was retried after `No such file or directory` error. [#4161](https://github.com/ClickHouse/ClickHouse/pull/4161) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed race condition when selecting from `system.tables` may give `table does not exist` error. [#4313](https://github.com/ClickHouse/ClickHouse/pull/4313) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   `clickhouse-client` can segfault on exit while loading data for command line suggestions if it was run in interactive mode. [#4317](https://github.com/ClickHouse/ClickHouse/pull/4317) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed a bug when the execution of mutations containing `IN` operators was producing incorrect results. [#4099](https://github.com/ClickHouse/ClickHouse/pull/4099) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Fixed error: if there is a database with `Dictionary` engine, all dictionaries forced to load at server startup, and if there is a dictionary with ClickHouse source from localhost, the dictionary cannot load. [#4255](https://github.com/ClickHouse/ClickHouse/pull/4255) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed error when system logs are tried to create again at server shutdown. [#4254](https://github.com/ClickHouse/ClickHouse/pull/4254) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Correctly return the right type and properly handle locks in `joinGet` function. [#4153](https://github.com/ClickHouse/ClickHouse/pull/4153) ([Amos Bird](https://github.com/amosbird))
+-   Added `sumMapWithOverflow` function. [#4151](https://github.com/ClickHouse/ClickHouse/pull/4151) ([Léo Ercolanelli](https://github.com/ercolanelli-leo))
+-   Fixed segfault with `allow_experimental_multiple_joins_emulation`. [52de2c](https://github.com/ClickHouse/ClickHouse/commit/52de2cd927f7b5257dd67e175f0a5560a48840d0) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed bug with incorrect `Date` and `DateTime` comparison. [#4237](https://github.com/ClickHouse/ClickHouse/pull/4237) ([valexey](https://github.com/valexey))
+-   Fixed fuzz test under undefined behavior sanitizer: added parameter type check for `quantile*Weighted` family of functions. [#4145](https://github.com/ClickHouse/ClickHouse/pull/4145) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed rare race condition when removing of old data parts can fail with `File not found` error. [#4378](https://github.com/ClickHouse/ClickHouse/pull/4378) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix install package with missing /etc/clickhouse-server/config.xml. [#4343](https://github.com/ClickHouse/ClickHouse/pull/4343) ([proller](https://github.com/proller))
+
+#### Build/Testing/Packaging Improvements {#buildtestingpackaging-improvements-5}
+
+-   Debian package: correct /etc/clickhouse-server/preprocessed link according to config. [#4205](https://github.com/ClickHouse/ClickHouse/pull/4205) ([proller](https://github.com/proller))
+-   Various build fixes for FreeBSD. [#4225](https://github.com/ClickHouse/ClickHouse/pull/4225) ([proller](https://github.com/proller))
+-   Added ability to create, fill and drop tables in perftest. [#4220](https://github.com/ClickHouse/ClickHouse/pull/4220) ([alesapin](https://github.com/alesapin))
+-   Added a script to check for duplicate includes. [#4326](https://github.com/ClickHouse/ClickHouse/pull/4326) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added ability to run queries by index in performance test. [#4264](https://github.com/ClickHouse/ClickHouse/pull/4264) ([alesapin](https://github.com/alesapin))
+-   Package with debug symbols is suggested to be installed. [#4274](https://github.com/ClickHouse/ClickHouse/pull/4274) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Refactoring of performance-test. Better logging and signals handling. [#4171](https://github.com/ClickHouse/ClickHouse/pull/4171) ([alesapin](https://github.com/alesapin))
+-   Added docs to anonymized Yandex.Metrika datasets. [#4164](https://github.com/ClickHouse/ClickHouse/pull/4164) ([alesapin](https://github.com/alesapin))
+-   Аdded tool for converting an old month-partitioned part to the custom-partitioned format. [#4195](https://github.com/ClickHouse/ClickHouse/pull/4195) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Added docs about two datasets in s3. [#4144](https://github.com/ClickHouse/ClickHouse/pull/4144) ([alesapin](https://github.com/alesapin))
+-   Added script which creates changelog from pull requests description. [#4169](https://github.com/ClickHouse/ClickHouse/pull/4169) [#4173](https://github.com/ClickHouse/ClickHouse/pull/4173) ([KochetovNicolai](https://github.com/KochetovNicolai)) ([KochetovNicolai](https://github.com/KochetovNicolai))
+-   Added puppet module for ClickHouse. [#4182](https://github.com/ClickHouse/ClickHouse/pull/4182) ([Maxim Fedotov](https://github.com/MaxFedotov))
+-   Added docs for a group of undocumented functions. [#4168](https://github.com/ClickHouse/ClickHouse/pull/4168) ([Winter Zhang](https://github.com/zhang2014))
+-   ARM build fixes. [#4210](https://github.com/ClickHouse/ClickHouse/pull/4210)[#4306](https://github.com/ClickHouse/ClickHouse/pull/4306) [#4291](https://github.com/ClickHouse/ClickHouse/pull/4291) ([proller](https://github.com/proller)) ([proller](https://github.com/proller))
+-   Dictionary tests now able to run from `ctest`. [#4189](https://github.com/ClickHouse/ClickHouse/pull/4189) ([proller](https://github.com/proller))
+-   Now `/etc/ssl` is used as default directory with SSL certificates. [#4167](https://github.com/ClickHouse/ClickHouse/pull/4167) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added checking SSE and AVX instruction at start. [#4234](https://github.com/ClickHouse/ClickHouse/pull/4234) ([Igr](https://github.com/igron99))
+-   Init script will wait server until start. [#4281](https://github.com/ClickHouse/ClickHouse/pull/4281) ([proller](https://github.com/proller))
+
+#### Backward Incompatible Changes {#backward-incompatible-changes-1}
+
+-   Removed `allow_experimental_low_cardinality_type` setting. `LowCardinality` data types are production ready. [#4323](https://github.com/ClickHouse/ClickHouse/pull/4323) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Reduce mark cache size and uncompressed cache size accordingly to available memory amount. [#4240](https://github.com/ClickHouse/ClickHouse/pull/4240) ([Lopatin Konstantin](https://github.com/k-lopatin)
+-   Added keyword `INDEX` in `CREATE TABLE` query. A column with name `index` must be quoted with backticks or double quotes: `` `index` ``. [#4143](https://github.com/ClickHouse/ClickHouse/pull/4143) ([Nikita Vasilev](https://github.com/nikvas0))
+-   `sumMap` now promote result type instead of overflow. The old `sumMap` behavior can be obtained by using `sumMapWithOverflow` function. [#4151](https://github.com/ClickHouse/ClickHouse/pull/4151) ([Léo Ercolanelli](https://github.com/ercolanelli-leo))
+
+#### Performance Improvements {#performance-improvements-4}
+
+-   `std::sort` replaced by `pdqsort` for queries without `LIMIT`. [#4236](https://github.com/ClickHouse/ClickHouse/pull/4236) ([Evgenii Pravda](https://github.com/kvinty))
+-   Now server reuse threads from global thread pool. This affects performance in some corner cases. [#4150](https://github.com/ClickHouse/ClickHouse/pull/4150) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Improvements {#improvements-5}
+
+-   Implemented AIO support for FreeBSD. [#4305](https://github.com/ClickHouse/ClickHouse/pull/4305) ([urgordeadbeef](https://github.com/urgordeadbeef))
+-   `SELECT * FROM a JOIN b USING a, b` now return `a` and `b` columns only from the left table. [#4141](https://github.com/ClickHouse/ClickHouse/pull/4141) ([Artem Zuikov](https://github.com/4ertus2))
+-   Allow `-C` option of client to work as `-c` option. [#4232](https://github.com/ClickHouse/ClickHouse/pull/4232) ([syominsergey](https://github.com/syominsergey))
+-   Now option `--password` used without value requires password from stdin. [#4230](https://github.com/ClickHouse/ClickHouse/pull/4230) ([BSD_Conqueror](https://github.com/bsd-conqueror))
+-   Added highlighting of unescaped metacharacters in string literals that contain `LIKE` expressions or regexps. [#4327](https://github.com/ClickHouse/ClickHouse/pull/4327) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added cancelling of HTTP read only queries if client socket goes away. [#4213](https://github.com/ClickHouse/ClickHouse/pull/4213) ([nvartolomei](https://github.com/nvartolomei))
+-   Now server reports progress to keep client connections alive. [#4215](https://github.com/ClickHouse/ClickHouse/pull/4215) ([Ivan](https://github.com/abyss7))
+-   Slightly better message with reason for OPTIMIZE query with `optimize_throw_if_noop` setting enabled. [#4294](https://github.com/ClickHouse/ClickHouse/pull/4294) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added support of `--version` option for clickhouse server. [#4251](https://github.com/ClickHouse/ClickHouse/pull/4251) ([Lopatin Konstantin](https://github.com/k-lopatin))
+-   Added `--help/-h` option to `clickhouse-server`. [#4233](https://github.com/ClickHouse/ClickHouse/pull/4233) ([Yuriy Baranov](https://github.com/yurriy))
+-   Added support for scalar subqueries with aggregate function state result. [#4348](https://github.com/ClickHouse/ClickHouse/pull/4348) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+-   Improved server shutdown time and ALTERs waiting time. [#4372](https://github.com/ClickHouse/ClickHouse/pull/4372) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added info about the replicated_can_become_leader setting to system.replicas and add logging if the replica won’t try to become leader. [#4379](https://github.com/ClickHouse/ClickHouse/pull/4379) ([Alex Zatelepin](https://github.com/ztlpn))
+
+## ClickHouse Release 19.1 {#clickhouse-release-19-1}
+
+### ClickHouse Release 19.1.14, 2019-03-14 {#clickhouse-release-19-1-14-2019-03-14}
+
+-   Fixed error `Column ... queried more than once` that may happen if the setting `asterisk_left_columns_only` is set to 1 in case of using `GLOBAL JOIN` with `SELECT *` (rare case). The issue does not exist in 19.3 and newer. [6bac7d8d](https://github.com/ClickHouse/ClickHouse/pull/4692/commits/6bac7d8d11a9b0d6de0b32b53c47eb2f6f8e7062) ([Artem Zuikov](https://github.com/4ertus2))
+
+### ClickHouse Release 19.1.13, 2019-03-12 {#clickhouse-release-19-1-13-2019-03-12}
+
+This release contains exactly the same set of patches as 19.3.7.
+
+### ClickHouse Release 19.1.10, 2019-03-03 {#clickhouse-release-19-1-10-2019-03-03}
+
+This release contains exactly the same set of patches as 19.3.6.
+
+## ClickHouse Release 19.1 {#clickhouse-release-19-1-1}
+
+### ClickHouse Release 19.1.9, 2019-02-21 {#clickhouse-release-19-1-9-2019-02-21}
+
+#### Bug Fixes {#bug-fixes-18}
+
+-   Fixed backward incompatibility with old versions due to wrong implementation of `send_logs_level` setting. [#4445](https://github.com/ClickHouse/ClickHouse/pull/4445) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed backward incompatibility of table function `remote` introduced with column comments. [#4446](https://github.com/ClickHouse/ClickHouse/pull/4446) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.1.8, 2019-02-16 {#clickhouse-release-19-1-8-2019-02-16}
+
+#### Bug Fixes {#bug-fixes-19}
+
+-   Fix install package with missing /etc/clickhouse-server/config.xml. [#4343](https://github.com/ClickHouse/ClickHouse/pull/4343) ([proller](https://github.com/proller))
+
+## ClickHouse Release 19.1 {#clickhouse-release-19-1-2}
+
+### ClickHouse Release 19.1.7, 2019-02-15 {#clickhouse-release-19-1-7-2019-02-15}
+
+#### Bug Fixes {#bug-fixes-20}
+
+-   Correctly return the right type and properly handle locks in `joinGet` function. [#4153](https://github.com/ClickHouse/ClickHouse/pull/4153) ([Amos Bird](https://github.com/amosbird))
+-   Fixed error when system logs are tried to create again at server shutdown. [#4254](https://github.com/ClickHouse/ClickHouse/pull/4254) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed error: if there is a database with `Dictionary` engine, all dictionaries forced to load at server startup, and if there is a dictionary with ClickHouse source from localhost, the dictionary cannot load. [#4255](https://github.com/ClickHouse/ClickHouse/pull/4255) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed a bug when the execution of mutations containing `IN` operators was producing incorrect results. [#4099](https://github.com/ClickHouse/ClickHouse/pull/4099) ([Alex Zatelepin](https://github.com/ztlpn))
+-   `clickhouse-client` can segfault on exit while loading data for command line suggestions if it was run in interactive mode. [#4317](https://github.com/ClickHouse/ClickHouse/pull/4317) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed race condition when selecting from `system.tables` may give `table does not exist` error. [#4313](https://github.com/ClickHouse/ClickHouse/pull/4313) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed deadlock when `SELECT` from a table with `File` engine was retried after `No such file or directory` error. [#4161](https://github.com/ClickHouse/ClickHouse/pull/4161) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed an issue: local ClickHouse dictionaries are loaded via TCP, but should load within process. [#4166](https://github.com/ClickHouse/ClickHouse/pull/4166) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed `No message received` error when interacting with PostgreSQL ODBC Driver through TLS connection. Also fixes segfault when using MySQL ODBC Driver. [#4170](https://github.com/ClickHouse/ClickHouse/pull/4170) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Temporarily disable predicate optimization for `ORDER BY`. [#3890](https://github.com/ClickHouse/ClickHouse/pull/3890) ([Winter Zhang](https://github.com/zhang2014))
+-   Fixed infinite loop when selecting from table function `numbers(0)`. [#4280](https://github.com/ClickHouse/ClickHouse/pull/4280) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed `compile_expressions` bug with comparison of big (more than int16) dates. [#4341](https://github.com/ClickHouse/ClickHouse/pull/4341) ([alesapin](https://github.com/alesapin))
+-   Fixed segmentation fault with `uncompressed_cache=1` and exception with wrong uncompressed size. [#4186](https://github.com/ClickHouse/ClickHouse/pull/4186) ([alesapin](https://github.com/alesapin))
+-   Fixed `ALL JOIN` with duplicates in right table. [#4184](https://github.com/ClickHouse/ClickHouse/pull/4184) ([Artem Zuikov](https://github.com/4ertus2))
+-   Fixed wrong behaviour when doing `INSERT ... SELECT ... FROM file(...)` query and file has `CSVWithNames` or `TSVWIthNames` format and the first data row is missing. [#4297](https://github.com/ClickHouse/ClickHouse/pull/4297) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed aggregate functions execution with `Array(LowCardinality)` arguments. [#4055](https://github.com/ClickHouse/ClickHouse/pull/4055) ([KochetovNicolai](https://github.com/KochetovNicolai))
+-   Debian package: correct /etc/clickhouse-server/preprocessed link according to config. [#4205](https://github.com/ClickHouse/ClickHouse/pull/4205) ([proller](https://github.com/proller))
+-   Fixed fuzz test under undefined behavior sanitizer: added parameter type check for `quantile*Weighted` family of functions. [#4145](https://github.com/ClickHouse/ClickHouse/pull/4145) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Make `START REPLICATED SENDS` command start replicated sends. [#4229](https://github.com/ClickHouse/ClickHouse/pull/4229) ([nvartolomei](https://github.com/nvartolomei))
+-   Fixed `Not found column` for duplicate columns in JOIN ON section. [#4279](https://github.com/ClickHouse/ClickHouse/pull/4279) ([Artem Zuikov](https://github.com/4ertus2))
+-   Now `/etc/ssl` is used as default directory with SSL certificates. [#4167](https://github.com/ClickHouse/ClickHouse/pull/4167) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed crash on dictionary reload if dictionary not available. [#4188](https://github.com/ClickHouse/ClickHouse/pull/4188) ([proller](https://github.com/proller))
+-   Fixed bug with incorrect `Date` and `DateTime` comparison. [#4237](https://github.com/ClickHouse/ClickHouse/pull/4237) ([valexey](https://github.com/valexey))
+-   Fixed incorrect result when `Date` and `DateTime` arguments are used in branches of conditional operator (function `if`). Added generic case for function `if`. [#4243](https://github.com/ClickHouse/ClickHouse/pull/4243) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+### ClickHouse Release 19.1.6, 2019-01-24 {#clickhouse-release-19-1-6-2019-01-24}
+
+#### New Features {#new-features-7}
+
+-   Custom per column compression codecs for tables. [#3899](https://github.com/ClickHouse/ClickHouse/pull/3899) [#4111](https://github.com/ClickHouse/ClickHouse/pull/4111) ([alesapin](https://github.com/alesapin), [Winter Zhang](https://github.com/zhang2014), [Anatoly](https://github.com/Sindbag))
+-   Added compression codec `Delta`. [#4052](https://github.com/ClickHouse/ClickHouse/pull/4052) ([alesapin](https://github.com/alesapin))
+-   Allow to `ALTER` compression codecs. [#4054](https://github.com/ClickHouse/ClickHouse/pull/4054) ([alesapin](https://github.com/alesapin))
+-   Added functions `left`, `right`, `trim`, `ltrim`, `rtrim`, `timestampadd`, `timestampsub` for SQL standard compatibility. [#3826](https://github.com/ClickHouse/ClickHouse/pull/3826) ([Ivan Blinkov](https://github.com/blinkov))
+-   Support for write in `HDFS` tables and `hdfs` table function. [#4084](https://github.com/ClickHouse/ClickHouse/pull/4084) ([alesapin](https://github.com/alesapin))
+-   Added functions to search for multiple constant strings from big haystack: `multiPosition`, `multiSearch` ,`firstMatch` also with `-UTF8`, `-CaseInsensitive`, and `-CaseInsensitiveUTF8` variants. [#4053](https://github.com/ClickHouse/ClickHouse/pull/4053) ([Danila Kutenin](https://github.com/danlark1))
+-   Pruning of unused shards if `SELECT` query filters by sharding key (setting `optimize_skip_unused_shards`). [#3851](https://github.com/ClickHouse/ClickHouse/pull/3851) ([Gleb Kanterov](https://github.com/kanterov), [Ivan](https://github.com/abyss7))
+-   Allow `Kafka` engine to ignore some number of parsing errors per block. [#4094](https://github.com/ClickHouse/ClickHouse/pull/4094) ([Ivan](https://github.com/abyss7))
+-   Added support for `CatBoost` multiclass models evaluation. Function `modelEvaluate` returns tuple with per-class raw predictions for multiclass models. `libcatboostmodel.so` should be built with [#607](https://github.com/catboost/catboost/pull/607). [#3959](https://github.com/ClickHouse/ClickHouse/pull/3959) ([KochetovNicolai](https://github.com/KochetovNicolai))
+-   Added functions `filesystemAvailable`, `filesystemFree`, `filesystemCapacity`. [#4097](https://github.com/ClickHouse/ClickHouse/pull/4097) ([Boris Granveaud](https://github.com/bgranvea))
+-   Added hashing functions `xxHash64` and `xxHash32`. [#3905](https://github.com/ClickHouse/ClickHouse/pull/3905) ([filimonov](https://github.com/filimonov))
+-   Added `gccMurmurHash` hashing function (GCC flavoured Murmur hash) which uses the same hash seed as [gcc](https://github.com/gcc-mirror/gcc/blob/41d6b10e96a1de98e90a7c0378437c3255814b16/libstdc%2B%2B-v3/include/bits/functional_hash.h#L191) [#4000](https://github.com/ClickHouse/ClickHouse/pull/4000) ([sundyli](https://github.com/sundy-li))
+-   Added hashing functions `javaHash`, `hiveHash`. [#3811](https://github.com/ClickHouse/ClickHouse/pull/3811) ([shangshujie365](https://github.com/shangshujie365))
+-   Added table function `remoteSecure`. Function works as `remote`, but uses secure connection. [#4088](https://github.com/ClickHouse/ClickHouse/pull/4088) ([proller](https://github.com/proller))
+
+#### Experimental Features {#experimental-features-3}
+
+-   Added multiple JOINs emulation (`allow_experimental_multiple_joins_emulation` setting). [#3946](https://github.com/ClickHouse/ClickHouse/pull/3946) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Bug Fixes {#bug-fixes-21}
+
+-   Make `compiled_expression_cache_size` setting limited by default to lower memory consumption. [#4041](https://github.com/ClickHouse/ClickHouse/pull/4041) ([alesapin](https://github.com/alesapin))
+-   Fix a bug that led to hangups in threads that perform ALTERs of Replicated tables and in the thread that updates configuration from ZooKeeper. [#2947](https://github.com/ClickHouse/ClickHouse/issues/2947) [#3891](https://github.com/ClickHouse/ClickHouse/issues/3891) [#3934](https://github.com/ClickHouse/ClickHouse/pull/3934) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Fixed a race condition when executing a distributed ALTER task. The race condition led to more than one replica trying to execute the task and all replicas except one failing with a ZooKeeper error. [#3904](https://github.com/ClickHouse/ClickHouse/pull/3904) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Fix a bug when `from_zk` config elements weren’t refreshed after a request to ZooKeeper timed out. [#2947](https://github.com/ClickHouse/ClickHouse/issues/2947) [#3947](https://github.com/ClickHouse/ClickHouse/pull/3947) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Fix bug with wrong prefix for IPv4 subnet masks. [#3945](https://github.com/ClickHouse/ClickHouse/pull/3945) ([alesapin](https://github.com/alesapin))
+-   Fixed crash (`std::terminate`) in rare cases when a new thread cannot be created due to exhausted resources. [#3956](https://github.com/ClickHouse/ClickHouse/pull/3956) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix bug when in `remote` table function execution when wrong restrictions were used for in `getStructureOfRemoteTable`. [#4009](https://github.com/ClickHouse/ClickHouse/pull/4009) ([alesapin](https://github.com/alesapin))
+-   Fix a leak of netlink sockets. They were placed in a pool where they were never deleted and new sockets were created at the start of a new thread when all current sockets were in use. [#4017](https://github.com/ClickHouse/ClickHouse/pull/4017) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Fix bug with closing `/proc/self/fd` directory earlier than all fds were read from `/proc` after forking `odbc-bridge` subprocess. [#4120](https://github.com/ClickHouse/ClickHouse/pull/4120) ([alesapin](https://github.com/alesapin))
+-   Fixed String to UInt monotonic conversion in case of usage String in primary key. [#3870](https://github.com/ClickHouse/ClickHouse/pull/3870) ([Winter Zhang](https://github.com/zhang2014))
+-   Fixed error in calculation of integer conversion function monotonicity. [#3921](https://github.com/ClickHouse/ClickHouse/pull/3921) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed segfault in `arrayEnumerateUniq`, `arrayEnumerateDense` functions in case of some invalid arguments. [#3909](https://github.com/ClickHouse/ClickHouse/pull/3909) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fix UB in StorageMerge. [#3910](https://github.com/ClickHouse/ClickHouse/pull/3910) ([Amos Bird](https://github.com/amosbird))
+-   Fixed segfault in functions `addDays`, `subtractDays`. [#3913](https://github.com/ClickHouse/ClickHouse/pull/3913) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed error: functions `round`, `floor`, `trunc`, `ceil` may return bogus result when executed on integer argument and large negative scale. [#3914](https://github.com/ClickHouse/ClickHouse/pull/3914) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed a bug induced by ‘kill query sync’ which leads to a core dump. [#3916](https://github.com/ClickHouse/ClickHouse/pull/3916) ([muVulDeePecker](https://github.com/fancyqlx))
+-   Fix bug with long delay after empty replication queue. [#3928](https://github.com/ClickHouse/ClickHouse/pull/3928) [#3932](https://github.com/ClickHouse/ClickHouse/pull/3932) ([alesapin](https://github.com/alesapin))
+-   Fixed excessive memory usage in case of inserting into table with `LowCardinality` primary key. [#3955](https://github.com/ClickHouse/ClickHouse/pull/3955) ([KochetovNicolai](https://github.com/KochetovNicolai))
+-   Fixed `LowCardinality` serialization for `Native` format in case of empty arrays. [#3907](https://github.com/ClickHouse/ClickHouse/issues/3907) [#4011](https://github.com/ClickHouse/ClickHouse/pull/4011) ([KochetovNicolai](https://github.com/KochetovNicolai))
+-   Fixed incorrect result while using distinct by single LowCardinality numeric column. [#3895](https://github.com/ClickHouse/ClickHouse/issues/3895) [#4012](https://github.com/ClickHouse/ClickHouse/pull/4012) ([KochetovNicolai](https://github.com/KochetovNicolai))
+-   Fixed specialized aggregation with LowCardinality key (in case when `compile` setting is enabled). [#3886](https://github.com/ClickHouse/ClickHouse/pull/3886) ([KochetovNicolai](https://github.com/KochetovNicolai))
+-   Fix user and password forwarding for replicated tables queries. [#3957](https://github.com/ClickHouse/ClickHouse/pull/3957) ([alesapin](https://github.com/alesapin)) ([小路](https://github.com/nicelulu))
+-   Fixed very rare race condition that can happen when listing tables in Dictionary database while reloading dictionaries. [#3970](https://github.com/ClickHouse/ClickHouse/pull/3970) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed incorrect result when HAVING was used with ROLLUP or CUBE. [#3756](https://github.com/ClickHouse/ClickHouse/issues/3756) [#3837](https://github.com/ClickHouse/ClickHouse/pull/3837) ([Sam Chou](https://github.com/reflection))
+-   Fixed column aliases for query with `JOIN ON` syntax and distributed tables. [#3980](https://github.com/ClickHouse/ClickHouse/pull/3980) ([Winter Zhang](https://github.com/zhang2014))
+-   Fixed error in internal implementation of `quantileTDigest` (found by Artem Vakhrushev). This error never happens in ClickHouse and was relevant only for those who use ClickHouse codebase as a library directly. [#3935](https://github.com/ClickHouse/ClickHouse/pull/3935) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Improvements {#improvements-6}
+
+-   Support for `IF NOT EXISTS` in `ALTER TABLE ADD COLUMN` statements along with `IF EXISTS` in `DROP/MODIFY/CLEAR/COMMENT COLUMN`. [#3900](https://github.com/ClickHouse/ClickHouse/pull/3900) ([Boris Granveaud](https://github.com/bgranvea))
+-   Function `parseDateTimeBestEffort`: support for formats `DD.MM.YYYY`, `DD.MM.YY`, `DD-MM-YYYY`, `DD-Mon-YYYY`, `DD/Month/YYYY` and similar. [#3922](https://github.com/ClickHouse/ClickHouse/pull/3922) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   `CapnProtoInputStream` now support jagged structures. [#4063](https://github.com/ClickHouse/ClickHouse/pull/4063) ([Odin Hultgren Van Der Horst](https://github.com/Miniwoffer))
+-   Usability improvement: added a check that server process is started from the data directory’s owner. Do not allow to start server from root if the data belongs to non-root user. [#3785](https://github.com/ClickHouse/ClickHouse/pull/3785) ([sergey-v-galtsev](https://github.com/sergey-v-galtsev))
+-   Better logic of checking required columns during analysis of queries with JOINs. [#3930](https://github.com/ClickHouse/ClickHouse/pull/3930) ([Artem Zuikov](https://github.com/4ertus2))
+-   Decreased the number of connections in case of large number of Distributed tables in a single server. [#3726](https://github.com/ClickHouse/ClickHouse/pull/3726) ([Winter Zhang](https://github.com/zhang2014))
+-   Supported totals row for `WITH TOTALS` query for ODBC driver. [#3836](https://github.com/ClickHouse/ClickHouse/pull/3836) ([Maksim Koritckiy](https://github.com/nightweb))
+-   Allowed to use `Enum`s as integers inside if function. [#3875](https://github.com/ClickHouse/ClickHouse/pull/3875) ([Ivan](https://github.com/abyss7))
+-   Added `low_cardinality_allow_in_native_format` setting. If disabled, do not use `LowCadrinality` type in `Native` format. [#3879](https://github.com/ClickHouse/ClickHouse/pull/3879) ([KochetovNicolai](https://github.com/KochetovNicolai))
+-   Removed some redundant objects from compiled expressions cache to lower memory usage. [#4042](https://github.com/ClickHouse/ClickHouse/pull/4042) ([alesapin](https://github.com/alesapin))
+-   Add check that `SET send_logs_level = 'value'` query accept appropriate value. [#3873](https://github.com/ClickHouse/ClickHouse/pull/3873) ([Sabyanin Maxim](https://github.com/s-mx))
+-   Fixed data type check in type conversion functions. [#3896](https://github.com/ClickHouse/ClickHouse/pull/3896) ([Winter Zhang](https://github.com/zhang2014))
+
+#### Performance Improvements {#performance-improvements-5}
+
+-   Add a MergeTree setting `use_minimalistic_part_header_in_zookeeper`. If enabled, Replicated tables will store compact part metadata in a single part znode. This can dramatically reduce ZooKeeper snapshot size (especially if the tables have a lot of columns). Note that after enabling this setting you will not be able to downgrade to a version that does not support it. [#3960](https://github.com/ClickHouse/ClickHouse/pull/3960) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Add an DFA-based implementation for functions `sequenceMatch` and `sequenceCount` in case pattern does not contain time. [#4004](https://github.com/ClickHouse/ClickHouse/pull/4004) ([Léo Ercolanelli](https://github.com/ercolanelli-leo))
+-   Performance improvement for integer numbers serialization. [#3968](https://github.com/ClickHouse/ClickHouse/pull/3968) ([Amos Bird](https://github.com/amosbird))
+-   Zero left padding PODArray so that -1 element is always valid and zeroed. It’s used for branchless calculation of offsets. [#3920](https://github.com/ClickHouse/ClickHouse/pull/3920) ([Amos Bird](https://github.com/amosbird))
+-   Reverted `jemalloc` version which lead to performance degradation. [#4018](https://github.com/ClickHouse/ClickHouse/pull/4018) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Backward Incompatible Changes {#backward-incompatible-changes-2}
+
+-   Removed undocumented feature `ALTER MODIFY PRIMARY KEY` because it was superseded by the `ALTER MODIFY ORDER BY` command. [#3887](https://github.com/ClickHouse/ClickHouse/pull/3887) ([Alex Zatelepin](https://github.com/ztlpn))
+-   Removed function `shardByHash`. [#3833](https://github.com/ClickHouse/ClickHouse/pull/3833) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Forbid using scalar subqueries with result of type `AggregateFunction`. [#3865](https://github.com/ClickHouse/ClickHouse/pull/3865) ([Ivan](https://github.com/abyss7))
+
+#### Build/Testing/Packaging Improvements {#buildtestingpackaging-improvements-6}
+
+-   Added support for PowerPC (`ppc64le`) build. [#4132](https://github.com/ClickHouse/ClickHouse/pull/4132) ([Danila Kutenin](https://github.com/danlark1))
+-   Stateful functional tests are run on public available dataset. [#3969](https://github.com/ClickHouse/ClickHouse/pull/3969) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed error when the server cannot start with the `bash: /usr/bin/clickhouse-extract-from-config: Operation not permitted` message within Docker or systemd-nspawn. [#4136](https://github.com/ClickHouse/ClickHouse/pull/4136) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Updated `rdkafka` library to v1.0.0-RC5. Used cppkafka instead of raw C interface. [#4025](https://github.com/ClickHouse/ClickHouse/pull/4025) ([Ivan](https://github.com/abyss7))
+-   Updated `mariadb-client` library. Fixed one of issues found by UBSan. [#3924](https://github.com/ClickHouse/ClickHouse/pull/3924) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Some fixes for UBSan builds. [#3926](https://github.com/ClickHouse/ClickHouse/pull/3926) [#3021](https://github.com/ClickHouse/ClickHouse/pull/3021) [#3948](https://github.com/ClickHouse/ClickHouse/pull/3948) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added per-commit runs of tests with UBSan build.
+-   Added per-commit runs of PVS-Studio static analyzer.
+-   Fixed bugs found by PVS-Studio. [#4013](https://github.com/ClickHouse/ClickHouse/pull/4013) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed glibc compatibility issues. [#4100](https://github.com/ClickHouse/ClickHouse/pull/4100) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Move Docker images to 18.10 and add compatibility file for glibc \>= 2.28 [#3965](https://github.com/ClickHouse/ClickHouse/pull/3965) ([alesapin](https://github.com/alesapin))
+-   Add env variable if user do not want to chown directories in server Docker image. [#3967](https://github.com/ClickHouse/ClickHouse/pull/3967) ([alesapin](https://github.com/alesapin))
+-   Enabled most of the warnings from `-Weverything` in clang. Enabled `-Wpedantic`. [#3986](https://github.com/ClickHouse/ClickHouse/pull/3986) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Added a few more warnings that are available only in clang 8. [#3993](https://github.com/ClickHouse/ClickHouse/pull/3993) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Link to `libLLVM` rather than to individual LLVM libs when using shared linking. [#3989](https://github.com/ClickHouse/ClickHouse/pull/3989) ([Orivej Desh](https://github.com/orivej))
+-   Added sanitizer variables for test images. [#4072](https://github.com/ClickHouse/ClickHouse/pull/4072) ([alesapin](https://github.com/alesapin))
+-   `clickhouse-server` debian package will recommend `libcap2-bin` package to use `setcap` tool for setting capabilities. This is optional. [#4093](https://github.com/ClickHouse/ClickHouse/pull/4093) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Improved compilation time, fixed includes. [#3898](https://github.com/ClickHouse/ClickHouse/pull/3898) ([proller](https://github.com/proller))
+-   Added performance tests for hash functions. [#3918](https://github.com/ClickHouse/ClickHouse/pull/3918) ([filimonov](https://github.com/filimonov))
+-   Fixed cyclic library dependences. [#3958](https://github.com/ClickHouse/ClickHouse/pull/3958) ([proller](https://github.com/proller))
+-   Improved compilation with low available memory. [#4030](https://github.com/ClickHouse/ClickHouse/pull/4030) ([proller](https://github.com/proller))
+-   Added test script to reproduce performance degradation in `jemalloc`. [#4036](https://github.com/ClickHouse/ClickHouse/pull/4036) ([alexey-milovidov](https://github.com/alexey-milovidov))
+-   Fixed misspells in comments and string literals under `dbms`. [#4122](https://github.com/ClickHouse/ClickHouse/pull/4122) ([maiha](https://github.com/maiha))
+-   Fixed typos in comments. [#4089](https://github.com/ClickHouse/ClickHouse/pull/4089) ([Evgenii Pravda](https://github.com/kvinty))
+
+## [Changelog for 2018](../../whats-new/changelog/2018.md#clickhouse-release-18-16) {#changelog-for-2018}
diff --git a/docs/en/reference/whats-new/changelog/2020.md b/docs/en/reference/whats-new/changelog/2020.md
new file mode 100644
index 00000000000..e0afe256777
--- /dev/null
+++ b/docs/en/reference/whats-new/changelog/2020.md
@@ -0,0 +1,3532 @@
+---
+toc_priority: 76
+toc_title: '2020'
+---
+
+### ClickHouse release 20.12
+
+### ClickHouse release v20.12.5.14-stable, 2020-12-28
+
+#### Bug Fix
+
+* Disable write with AIO during merges because it can lead to extremely rare data corruption of primary key columns during merge. [#18481](https://github.com/ClickHouse/ClickHouse/pull/18481) ([alesapin](https://github.com/alesapin)).
+* Fixed `value is too short` error when executing `toType(...)` functions (`toDate`, `toUInt32`, etc) with argument of type `Nullable(String)`. Now such functions return `NULL` on parsing errors instead of throwing exception. Fixes [#7673](https://github.com/ClickHouse/ClickHouse/issues/7673). [#18445](https://github.com/ClickHouse/ClickHouse/pull/18445) ([tavplubix](https://github.com/tavplubix)).
+* Restrict merges from wide to compact parts. In case of vertical merge it led to broken result part. [#18381](https://github.com/ClickHouse/ClickHouse/pull/18381) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix filling table `system.settings_profile_elements`. This PR fixes [#18231](https://github.com/ClickHouse/ClickHouse/issues/18231). [#18379](https://github.com/ClickHouse/ClickHouse/pull/18379) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix possible crashes in aggregate functions with combinator `Distinct`, while using two-level aggregation. Fixes [#17682](https://github.com/ClickHouse/ClickHouse/issues/17682). [#18365](https://github.com/ClickHouse/ClickHouse/pull/18365) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix error when query `MODIFY COLUMN ... REMOVE TTL` does not actually remove column TTL. [#18130](https://github.com/ClickHouse/ClickHouse/pull/18130) ([alesapin](https://github.com/alesapin)).
+
+#### Build/Testing/Packaging Improvement
+
+* Update timezones info to 2020e. [#18531](https://github.com/ClickHouse/ClickHouse/pull/18531) ([alesapin](https://github.com/alesapin)).
+
+
+### ClickHouse release v20.12.4.5-stable, 2020-12-24
+
+#### Bug Fix
+
+* Fixed issue when `clickhouse-odbc-bridge` process is unreachable by server on machines with dual IPv4/IPv6 stack; - Fixed issue when ODBC dictionary updates are performed using malformed queries and/or cause crashes; Possibly closes [#14489](https://github.com/ClickHouse/ClickHouse/issues/14489). [#18278](https://github.com/ClickHouse/ClickHouse/pull/18278) ([Denis Glazachev](https://github.com/traceon)).
+* Fixed key comparison between Enum and Int types. This fixes [#17989](https://github.com/ClickHouse/ClickHouse/issues/17989). [#18214](https://github.com/ClickHouse/ClickHouse/pull/18214) ([Amos Bird](https://github.com/amosbird)).
+* Fixed unique key convert crash in `MaterializeMySQL` database engine. This fixes [#18186](https://github.com/ClickHouse/ClickHouse/issues/18186) and fixes [#16372](https://github.com/ClickHouse/ClickHouse/issues/16372)  [#18211](https://github.com/ClickHouse/ClickHouse/pull/18211) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed `std::out_of_range: basic_string` in S3 URL parsing. [#18059](https://github.com/ClickHouse/ClickHouse/pull/18059) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fixed the issue when some tables not synchronized to ClickHouse from MySQL caused by the fact that convertion MySQL prefix index wasn't supported for MaterializeMySQL. This fixes [#15187](https://github.com/ClickHouse/ClickHouse/issues/15187) and fixes [#17912](https://github.com/ClickHouse/ClickHouse/issues/17912)  [#17944](https://github.com/ClickHouse/ClickHouse/pull/17944) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed the issue when query optimization was producing wrong result if query contains `ARRAY JOIN`. [#17887](https://github.com/ClickHouse/ClickHouse/pull/17887) ([sundyli](https://github.com/sundy-li)).
+* Fixed possible segfault in `topK` aggregate function. This closes [#17404](https://github.com/ClickHouse/ClickHouse/issues/17404). [#17845](https://github.com/ClickHouse/ClickHouse/pull/17845) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fixed empty `system.stack_trace` table when server is running in daemon mode. [#17630](https://github.com/ClickHouse/ClickHouse/pull/17630) ([Amos Bird](https://github.com/amosbird)).
+
+
+### ClickHouse release v20.12.3.3-stable, 2020-12-13
+
+#### Backward Incompatible Change
+
+* Enable `use_compact_format_in_distributed_parts_names` by default (see the documentation for the reference). [#16728](https://github.com/ClickHouse/ClickHouse/pull/16728) ([Azat Khuzhin](https://github.com/azat)).
+* Accept user settings related to file formats (e.g. `format_csv_delimiter`) in the `SETTINGS` clause when creating a table that uses `File` engine, and use these settings in all `INSERT`s and `SELECT`s. The file format settings changed in the current user session, or in the `SETTINGS` clause of a DML query itself, no longer affect the query. [#16591](https://github.com/ClickHouse/ClickHouse/pull/16591) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+
+#### New Feature
+
+* add `*.xz` compression/decompression support.It enables using `*.xz` in `file()` function. This closes [#8828](https://github.com/ClickHouse/ClickHouse/issues/8828). [#16578](https://github.com/ClickHouse/ClickHouse/pull/16578) ([Abi Palagashvili](https://github.com/fibersel)).
+* Introduce the query `ALTER TABLE ... DROP|DETACH PART 'part_name'`. [#15511](https://github.com/ClickHouse/ClickHouse/pull/15511) ([nvartolomei](https://github.com/nvartolomei)).
+* Added new ALTER UPDATE/DELETE IN PARTITION syntax. [#13403](https://github.com/ClickHouse/ClickHouse/pull/13403) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Allow formatting named tuples as JSON objects when using JSON input/output formats, controlled by the `output_format_json_named_tuples_as_objects` setting, disabled by default. [#17175](https://github.com/ClickHouse/ClickHouse/pull/17175) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Add a possibility to input enum value as it's id in TSV and CSV formats by default. [#16834](https://github.com/ClickHouse/ClickHouse/pull/16834) ([Kruglov Pavel](https://github.com/Avogar)).
+* Add COLLATE support for Nullable, LowCardinality, Array and Tuple, where nested type is String. Also refactor the code associated with collations in ColumnString.cpp. [#16273](https://github.com/ClickHouse/ClickHouse/pull/16273) ([Kruglov Pavel](https://github.com/Avogar)).
+* New `tcpPort` function returns TCP port listened by this server. [#17134](https://github.com/ClickHouse/ClickHouse/pull/17134) ([Ivan](https://github.com/abyss7)).
+* Add new math functions: `acosh`, `asinh`, `atan2`, `atanh`, `cosh`, `hypot`, `log1p`, `sinh`. [#16636](https://github.com/ClickHouse/ClickHouse/pull/16636) ([Konstantin Malanchev](https://github.com/hombit)).
+* Possibility to distribute the merges between different replicas. Introduces the `execute_merges_on_single_replica_time_threshold` mergetree setting. [#16424](https://github.com/ClickHouse/ClickHouse/pull/16424) ([filimonov](https://github.com/filimonov)).
+* Add setting `aggregate_functions_null_for_empty` for SQL standard compatibility. This option will rewrite all aggregate functions in a query, adding -OrNull suffix to them. Implements [10273](https://github.com/ClickHouse/ClickHouse/issues/10273). [#16123](https://github.com/ClickHouse/ClickHouse/pull/16123) ([flynn](https://github.com/ucasFL)).
+* Updated DateTime, DateTime64 parsing to accept string Date literal format. [#16040](https://github.com/ClickHouse/ClickHouse/pull/16040) ([Maksim Kita](https://github.com/kitaisreal)).
+* Make it possible to change the path to history file in `clickhouse-client` using the `--history_file` parameter. [#15960](https://github.com/ClickHouse/ClickHouse/pull/15960) ([Maksim Kita](https://github.com/kitaisreal)).
+
+#### Bug Fix
+
+* Fix the issue when server can stop accepting connections in very rare cases. [#17542](https://github.com/ClickHouse/ClickHouse/pull/17542) ([Amos Bird](https://github.com/amosbird)).
+* Fixed `Function not implemented` error when executing `RENAME` query in `Atomic` database with ClickHouse running on Windows Subsystem for Linux. Fixes [#17661](https://github.com/ClickHouse/ClickHouse/issues/17661). [#17664](https://github.com/ClickHouse/ClickHouse/pull/17664) ([tavplubix](https://github.com/tavplubix)).
+* Do not restore parts from WAL if `in_memory_parts_enable_wal` is disabled. [#17802](https://github.com/ClickHouse/ClickHouse/pull/17802) ([detailyang](https://github.com/detailyang)).
+* fix incorrect initialization of `max_compress_block_size` of MergeTreeWriterSettings with `min_compress_block_size`. [#17833](https://github.com/ClickHouse/ClickHouse/pull/17833) ([flynn](https://github.com/ucasFL)).
+* Exception message about max table size to drop was displayed incorrectly. [#17764](https://github.com/ClickHouse/ClickHouse/pull/17764) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed possible segfault when there is not enough space when inserting into `Distributed` table. [#17737](https://github.com/ClickHouse/ClickHouse/pull/17737) ([tavplubix](https://github.com/tavplubix)).
+* Fixed problem when ClickHouse fails to resume connection to MySQL servers. [#17681](https://github.com/ClickHouse/ClickHouse/pull/17681) ([Alexander Kazakov](https://github.com/Akazz)).
+* In might be determined incorrectly if cluster is circular- (cross-) replicated or not when executing `ON CLUSTER` query due to race condition when `pool_size` > 1. It's fixed. [#17640](https://github.com/ClickHouse/ClickHouse/pull/17640) ([tavplubix](https://github.com/tavplubix)).
+* Exception `fmt::v7::format_error` can be logged in background for MergeTree tables. This fixes [#17613](https://github.com/ClickHouse/ClickHouse/issues/17613). [#17615](https://github.com/ClickHouse/ClickHouse/pull/17615) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* When clickhouse-client is used in interactive mode with multiline queries, single line comment was erronously extended till the end of query. This fixes [#13654](https://github.com/ClickHouse/ClickHouse/issues/13654). [#17565](https://github.com/ClickHouse/ClickHouse/pull/17565) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix alter query hang when the corresponding mutation was killed on the different replica. Fixes [#16953](https://github.com/ClickHouse/ClickHouse/issues/16953). [#17499](https://github.com/ClickHouse/ClickHouse/pull/17499) ([alesapin](https://github.com/alesapin)).
+* Fix issue when mark cache size was underestimated by clickhouse. It may happen when there are a lot of tiny files with marks. [#17496](https://github.com/ClickHouse/ClickHouse/pull/17496) ([alesapin](https://github.com/alesapin)).
+* Fix `ORDER BY` with enabled setting `optimize_redundant_functions_in_order_by`. [#17471](https://github.com/ClickHouse/ClickHouse/pull/17471) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix duplicates after `DISTINCT` which were possible because of incorrect optimization. Fixes [#17294](https://github.com/ClickHouse/ClickHouse/issues/17294). [#17296](https://github.com/ClickHouse/ClickHouse/pull/17296) ([li chengxiang](https://github.com/chengxianglibra)). [#17439](https://github.com/ClickHouse/ClickHouse/pull/17439) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix crash while reading from `JOIN` table with `LowCardinality` types. Fixes [#17228](https://github.com/ClickHouse/ClickHouse/issues/17228). [#17397](https://github.com/ClickHouse/ClickHouse/pull/17397) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* fix `toInt256(inf)` stack overflow. Int256 is an experimental feature. Closed [#17235](https://github.com/ClickHouse/ClickHouse/issues/17235). [#17257](https://github.com/ClickHouse/ClickHouse/pull/17257) ([flynn](https://github.com/ucasFL)).
+* Fix possible `Unexpected packet Data received from client` error logged for Distributed queries with `LIMIT`. [#17254](https://github.com/ClickHouse/ClickHouse/pull/17254) ([Azat Khuzhin](https://github.com/azat)).
+* Fix set index invalidation when there are const columns in the subquery. This fixes [#17246](https://github.com/ClickHouse/ClickHouse/issues/17246). [#17249](https://github.com/ClickHouse/ClickHouse/pull/17249) ([Amos Bird](https://github.com/amosbird)).
+* Fix possible wrong index analysis when the types of the index comparison are different. This fixes [#17122](https://github.com/ClickHouse/ClickHouse/issues/17122). [#17145](https://github.com/ClickHouse/ClickHouse/pull/17145) ([Amos Bird](https://github.com/amosbird)).
+* Fix ColumnConst comparison which leads to crash. This fixed [#17088](https://github.com/ClickHouse/ClickHouse/issues/17088) . [#17135](https://github.com/ClickHouse/ClickHouse/pull/17135) ([Amos Bird](https://github.com/amosbird)).
+* Multiple fixed for MaterializeMySQL (experimental feature). Fixes [#16923](https://github.com/ClickHouse/ClickHouse/issues/16923) Fixes [#15883](https://github.com/ClickHouse/ClickHouse/issues/15883) Fix MaterializeMySQL SYNC failure when the modify MySQL binlog_checksum. [#17091](https://github.com/ClickHouse/ClickHouse/pull/17091) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix bug when `ON CLUSTER` queries may hang forever for non-leader ReplicatedMergeTreeTables. [#17089](https://github.com/ClickHouse/ClickHouse/pull/17089) ([alesapin](https://github.com/alesapin)).
+* Fixed crash on `CREATE TABLE ... AS some_table` query when `some_table` was created `AS table_function()` Fixes [#16944](https://github.com/ClickHouse/ClickHouse/issues/16944). [#17072](https://github.com/ClickHouse/ClickHouse/pull/17072) ([tavplubix](https://github.com/tavplubix)).
+* Bug unfinished implementation for funciton fuzzBits, related issue: [#16980](https://github.com/ClickHouse/ClickHouse/issues/16980). [#17051](https://github.com/ClickHouse/ClickHouse/pull/17051) ([hexiaoting](https://github.com/hexiaoting)).
+* Fix LLVM's libunwind in the case when CFA register is RAX. This is the [bug](https://bugs.llvm.org/show_bug.cgi?id=48186) in [LLVM's libunwind](https://github.com/llvm/llvm-project/tree/master/libunwind). We already have workarounds for this bug. [#17046](https://github.com/ClickHouse/ClickHouse/pull/17046) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Avoid unnecessary network errors for remote queries which may be cancelled while execution, like queries with `LIMIT`. [#17006](https://github.com/ClickHouse/ClickHouse/pull/17006) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `optimize_distributed_group_by_sharding_key` setting (that is disabled by default) for query with OFFSET only. [#16996](https://github.com/ClickHouse/ClickHouse/pull/16996) ([Azat Khuzhin](https://github.com/azat)).
+* Fix for Merge tables over Distributed tables with JOIN. [#16993](https://github.com/ClickHouse/ClickHouse/pull/16993) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed wrong result in big integers (128, 256 bit) when casting from double. Big integers support is experimental. [#16986](https://github.com/ClickHouse/ClickHouse/pull/16986) ([Mike](https://github.com/myrrc)).
+* Fix possible server crash after `ALTER TABLE ... MODIFY COLUMN ... NewType` when `SELECT` have `WHERE` expression on altering column and alter does not finished yet. [#16968](https://github.com/ClickHouse/ClickHouse/pull/16968) ([Amos Bird](https://github.com/amosbird)).
+* Blame info was not calculated correctly in `clickhouse-git-import`. [#16959](https://github.com/ClickHouse/ClickHouse/pull/16959) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix order by optimization with monotonous functions. Fixes [#16107](https://github.com/ClickHouse/ClickHouse/issues/16107). [#16956](https://github.com/ClickHouse/ClickHouse/pull/16956) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix optimization of group by with enabled setting `optimize_aggregators_of_group_by_keys` and joins. Fixes [#12604](https://github.com/ClickHouse/ClickHouse/issues/12604). [#16951](https://github.com/ClickHouse/ClickHouse/pull/16951) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix possible error `Illegal type of argument` for queries with `ORDER BY`. Fixes [#16580](https://github.com/ClickHouse/ClickHouse/issues/16580). [#16928](https://github.com/ClickHouse/ClickHouse/pull/16928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix strange code in InterpreterShowAccessQuery. [#16866](https://github.com/ClickHouse/ClickHouse/pull/16866) ([tavplubix](https://github.com/tavplubix)).
+* Prevent clickhouse server crashes when using the function `timeSeriesGroupSum`. The function is removed from newer ClickHouse releases. [#16865](https://github.com/ClickHouse/ClickHouse/pull/16865) ([filimonov](https://github.com/filimonov)).
+* Fix rare silent crashes when query profiler is on and ClickHouse is installed on OS with glibc version that has (supposedly) broken asynchronous unwind tables for some functions. This fixes [#15301](https://github.com/ClickHouse/ClickHouse/issues/15301). This fixes [#13098](https://github.com/ClickHouse/ClickHouse/issues/13098). [#16846](https://github.com/ClickHouse/ClickHouse/pull/16846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash when using `any` without any arguments. This is for [#16803](https://github.com/ClickHouse/ClickHouse/issues/16803) . cc @azat. [#16826](https://github.com/ClickHouse/ClickHouse/pull/16826) ([Amos Bird](https://github.com/amosbird)).
+* If no memory can be allocated while writing table metadata on disk, broken metadata file can be written. [#16772](https://github.com/ClickHouse/ClickHouse/pull/16772) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix trivial query optimization with partition predicate. [#16767](https://github.com/ClickHouse/ClickHouse/pull/16767) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `IN` operator over several columns and tuples with enabled `transform_null_in` setting. Fixes [#15310](https://github.com/ClickHouse/ClickHouse/issues/15310). [#16722](https://github.com/ClickHouse/ClickHouse/pull/16722) ([Anton Popov](https://github.com/CurtizJ)).
+* Return number of affected rows for INSERT queries via MySQL protocol. Previously ClickHouse used to always return 0, it's fixed. Fixes [#16605](https://github.com/ClickHouse/ClickHouse/issues/16605). [#16715](https://github.com/ClickHouse/ClickHouse/pull/16715) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix remote query failure when using 'if' suffix aggregate function. Fixes [#16574](https://github.com/ClickHouse/ClickHouse/issues/16574) Fixes [#16231](https://github.com/ClickHouse/ClickHouse/issues/16231) [#16610](https://github.com/ClickHouse/ClickHouse/pull/16610) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix inconsistent behavior caused by `select_sequential_consistency` for optimized trivial count query and system.tables. [#16309](https://github.com/ClickHouse/ClickHouse/pull/16309) ([Hao Chen](https://github.com/haoch)).
+
+#### Improvement
+
+* Remove empty parts after they were pruned by TTL, mutation, or collapsing merge algorithm. [#16895](https://github.com/ClickHouse/ClickHouse/pull/16895) ([Anton Popov](https://github.com/CurtizJ)).
+* Enable compact format of directories for asynchronous sends in Distributed tables: `use_compact_format_in_distributed_parts_names` is set to 1 by default. [#16788](https://github.com/ClickHouse/ClickHouse/pull/16788) ([Azat Khuzhin](https://github.com/azat)).
+* Abort multipart upload if no data was written to S3. [#16840](https://github.com/ClickHouse/ClickHouse/pull/16840) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Reresolve the IP of the `format_avro_schema_registry_url` in case of errors. [#16985](https://github.com/ClickHouse/ClickHouse/pull/16985) ([filimonov](https://github.com/filimonov)).
+* Mask password in data_path in the system.distribution_queue. [#16727](https://github.com/ClickHouse/ClickHouse/pull/16727) ([Azat Khuzhin](https://github.com/azat)).
+* Throw error when use column transformer replaces non existing column. [#16183](https://github.com/ClickHouse/ClickHouse/pull/16183) ([hexiaoting](https://github.com/hexiaoting)).
+* Turn off parallel parsing when there is no enough memory for all threads to work simultaneously. Also there could be exceptions like "Memory limit exceeded" when somebody will try to insert extremely huge rows (> min_chunk_bytes_for_parallel_parsing), because each piece to parse has to be independent set of strings (one or more). [#16721](https://github.com/ClickHouse/ClickHouse/pull/16721) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Install script should always create subdirs in config folders. This is only relevant for Docker build with custom config. [#16936](https://github.com/ClickHouse/ClickHouse/pull/16936) ([filimonov](https://github.com/filimonov)).
+* Correct grammar in error message in JSONEachRow, JSONCompactEachRow, and RegexpRow input formats. [#17205](https://github.com/ClickHouse/ClickHouse/pull/17205) ([nico piderman](https://github.com/sneako)).
+* Set default `host` and `port` parameters for `SOURCE(CLICKHOUSE(...))` to current instance and set default `user` value to `'default'`. [#16997](https://github.com/ClickHouse/ClickHouse/pull/16997) ([vdimir](https://github.com/vdimir)).
+* Throw an informative error message when doing `ATTACH/DETACH TABLE <DICTIONARY>`. Before this PR, `detach table <dict>` works but leads to an ill-formed in-memory metadata. [#16885](https://github.com/ClickHouse/ClickHouse/pull/16885) ([Amos Bird](https://github.com/amosbird)).
+* Add cutToFirstSignificantSubdomainWithWWW(). [#16845](https://github.com/ClickHouse/ClickHouse/pull/16845) ([Azat Khuzhin](https://github.com/azat)).
+* Server refused to startup with exception message if wrong config is given (`metric_log`.`collect_interval_milliseconds` is missing). [#16815](https://github.com/ClickHouse/ClickHouse/pull/16815) ([Ivan](https://github.com/abyss7)).
+* Better exception message when configuration for distributed DDL is absent. This fixes [#5075](https://github.com/ClickHouse/ClickHouse/issues/5075). [#16769](https://github.com/ClickHouse/ClickHouse/pull/16769) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Usability improvement: better suggestions in syntax error message when `CODEC` expression is misplaced in `CREATE TABLE` query. This fixes [#12493](https://github.com/ClickHouse/ClickHouse/issues/12493). [#16768](https://github.com/ClickHouse/ClickHouse/pull/16768) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove empty directories for async INSERT at start of Distributed engine. [#16729](https://github.com/ClickHouse/ClickHouse/pull/16729) ([Azat Khuzhin](https://github.com/azat)).
+* Workaround for use S3 with nginx server as proxy. Nginx currenty does not accept urls with empty path like `http://domain.com?delete`, but vanilla aws-sdk-cpp produces this kind of urls. This commit uses patched aws-sdk-cpp version, which makes urls with "/" as path in this cases, like `http://domain.com/?delete`. [#16709](https://github.com/ClickHouse/ClickHouse/pull/16709) ([ianton-ru](https://github.com/ianton-ru)).
+* Allow `reinterpretAs*` functions to work for integers and floats of the same size. Implements [16640](https://github.com/ClickHouse/ClickHouse/issues/16640). [#16657](https://github.com/ClickHouse/ClickHouse/pull/16657) ([flynn](https://github.com/ucasFL)).
+* Now, `<auxiliary_zookeepers>` configuration can be changed in `config.xml` and reloaded without server startup. [#16627](https://github.com/ClickHouse/ClickHouse/pull/16627) ([Amos Bird](https://github.com/amosbird)).
+* Support SNI in https connections to remote resources. This will allow to connect to Cloudflare servers that require SNI. This fixes [#10055](https://github.com/ClickHouse/ClickHouse/issues/10055). [#16252](https://github.com/ClickHouse/ClickHouse/pull/16252) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make it possible to connect to `clickhouse-server` secure endpoint which requires SNI. This is possible when `clickhouse-server` is hosted behind TLS proxy. [#16938](https://github.com/ClickHouse/ClickHouse/pull/16938) ([filimonov](https://github.com/filimonov)).
+* Fix possible stack overflow if a loop of materialized views is created. This closes [#15732](https://github.com/ClickHouse/ClickHouse/issues/15732). [#16048](https://github.com/ClickHouse/ClickHouse/pull/16048) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Simplify the implementation of background tasks processing for the MergeTree table engines family. There should be no visible changes for user. [#15983](https://github.com/ClickHouse/ClickHouse/pull/15983) ([alesapin](https://github.com/alesapin)).
+* Improvement for MaterializeMySQL (experimental feature). Throw exception about right sync privileges when MySQL sync user has error privileges. [#15977](https://github.com/ClickHouse/ClickHouse/pull/15977) ([TCeason](https://github.com/TCeason)).
+* Made `indexOf()` use BloomFilter. [#14977](https://github.com/ClickHouse/ClickHouse/pull/14977) ([achimbab](https://github.com/achimbab)).
+
+#### Performance Improvement
+
+* Use Floyd-Rivest algorithm, it is the best for the ClickHouse use case of partial sorting. Bechmarks are in https://github.com/danlark1/miniselect and [here](https://drive.google.com/drive/folders/1DHEaeXgZuX6AJ9eByeZ8iQVQv0ueP8XM). [#16825](https://github.com/ClickHouse/ClickHouse/pull/16825) ([Danila Kutenin](https://github.com/danlark1)).
+* Now `ReplicatedMergeTree` tree engines family uses a separate thread pool for replicated fetches. Size of the pool limited by setting `background_fetches_pool_size` which can be tuned with a server restart. The default value of the setting is 3 and it means that the maximum amount of parallel fetches is equal to 3 (and it allows to utilize 10G network). Fixes #520. [#16390](https://github.com/ClickHouse/ClickHouse/pull/16390) ([alesapin](https://github.com/alesapin)).
+* Fixed uncontrolled growth of the state of `quantileTDigest`. [#16680](https://github.com/ClickHouse/ClickHouse/pull/16680) ([hrissan](https://github.com/hrissan)).
+* Add `VIEW` subquery description to `EXPLAIN`. Limit push down optimisation for `VIEW`. Add local replicas of `Distributed` to query plan. [#14936](https://github.com/ClickHouse/ClickHouse/pull/14936) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix optimize_read_in_order/optimize_aggregation_in_order with max_threads > 0 and expression in ORDER BY. [#16637](https://github.com/ClickHouse/ClickHouse/pull/16637) ([Azat Khuzhin](https://github.com/azat)).
+* Fix performance of reading from `Merge` tables over huge number of `MergeTree` tables. Fixes [#7748](https://github.com/ClickHouse/ClickHouse/issues/7748). [#16988](https://github.com/ClickHouse/ClickHouse/pull/16988) ([Anton Popov](https://github.com/CurtizJ)).
+* Now we can safely prune partitions with exact match. Useful case: Suppose table is partitioned by `intHash64(x) % 100` and the query has condition on `intHash64(x) % 100` verbatim, not on x. [#16253](https://github.com/ClickHouse/ClickHouse/pull/16253) ([Amos Bird](https://github.com/amosbird)).
+
+#### Experimental Feature
+
+* Add `EmbeddedRocksDB` table engine (can be used for dictionaries). [#15073](https://github.com/ClickHouse/ClickHouse/pull/15073) ([sundyli](https://github.com/sundy-li)).
+
+#### Build/Testing/Packaging Improvement
+
+* Improvements in test coverage building images. [#17233](https://github.com/ClickHouse/ClickHouse/pull/17233) ([alesapin](https://github.com/alesapin)).
+* Update embedded timezone data to version 2020d (also update cctz to the latest master). [#17204](https://github.com/ClickHouse/ClickHouse/pull/17204) ([filimonov](https://github.com/filimonov)).
+* Fix UBSan report in Poco. This closes [#12719](https://github.com/ClickHouse/ClickHouse/issues/12719). [#16765](https://github.com/ClickHouse/ClickHouse/pull/16765) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Do not instrument 3rd-party libraries with UBSan. [#16764](https://github.com/ClickHouse/ClickHouse/pull/16764) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix UBSan report in cache dictionaries. This closes [#12641](https://github.com/ClickHouse/ClickHouse/issues/12641). [#16763](https://github.com/ClickHouse/ClickHouse/pull/16763) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix UBSan report when trying to convert infinite floating point number to integer. This closes [#14190](https://github.com/ClickHouse/ClickHouse/issues/14190). [#16677](https://github.com/ClickHouse/ClickHouse/pull/16677) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+
+## ClickHouse release 20.11
+
+### ClickHouse release v20.11.7.16-stable, 2021-03-02
+
+#### Improvement
+
+* Explicitly set uid / gid of clickhouse user & group to the fixed values (101) in clickhouse-server images. [#19096](https://github.com/ClickHouse/ClickHouse/pull/19096) ([filimonov](https://github.com/filimonov)).
+
+#### Bug Fix
+
+* BloomFilter index crash fix. Fixes [#19757](https://github.com/ClickHouse/ClickHouse/issues/19757). [#19884](https://github.com/ClickHouse/ClickHouse/pull/19884) ([Maksim Kita](https://github.com/kitaisreal)).
+* Deadlock was possible if system.text_log is enabled. This fixes [#19874](https://github.com/ClickHouse/ClickHouse/issues/19874). [#19875](https://github.com/ClickHouse/ClickHouse/pull/19875) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* In previous versions, unusual arguments for function arrayEnumerateUniq may cause crash or infinite loop. This closes [#19787](https://github.com/ClickHouse/ClickHouse/issues/19787). [#19788](https://github.com/ClickHouse/ClickHouse/pull/19788) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed stack overflow when using accurate comparison of arithmetic type with string type. [#19773](https://github.com/ClickHouse/ClickHouse/pull/19773) ([tavplubix](https://github.com/tavplubix)).
+* Fix a segmentation fault in `bitmapAndnot` function. Fixes [#19668](https://github.com/ClickHouse/ClickHouse/issues/19668). [#19713](https://github.com/ClickHouse/ClickHouse/pull/19713) ([Maksim Kita](https://github.com/kitaisreal)).
+* Some functions with big integers may cause segfault. Big integers is experimental feature. This closes [#19667](https://github.com/ClickHouse/ClickHouse/issues/19667). [#19672](https://github.com/ClickHouse/ClickHouse/pull/19672) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix wrong result of function `neighbor` for `LowCardinality` argument. Fixes [#10333](https://github.com/ClickHouse/ClickHouse/issues/10333). [#19617](https://github.com/ClickHouse/ClickHouse/pull/19617) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix use-after-free of the CompressedWriteBuffer in Connection after disconnect. [#19599](https://github.com/ClickHouse/ClickHouse/pull/19599) ([Azat Khuzhin](https://github.com/azat)).
+* `DROP/DETACH TABLE table ON CLUSTER cluster SYNC` query might hang, it's fixed. Fixes [#19568](https://github.com/ClickHouse/ClickHouse/issues/19568). [#19572](https://github.com/ClickHouse/ClickHouse/pull/19572) ([tavplubix](https://github.com/tavplubix)).
+* Query CREATE DICTIONARY id expression fix. [#19571](https://github.com/ClickHouse/ClickHouse/pull/19571) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix SIGSEGV with merge_tree_min_rows_for_concurrent_read/merge_tree_min_bytes_for_concurrent_read=0/UINT64_MAX. [#19528](https://github.com/ClickHouse/ClickHouse/pull/19528) ([Azat Khuzhin](https://github.com/azat)).
+* Buffer overflow (on memory read) was possible if `addMonth` function was called with specifically crafted arguments. This fixes [#19441](https://github.com/ClickHouse/ClickHouse/issues/19441). This fixes [#19413](https://github.com/ClickHouse/ClickHouse/issues/19413). [#19472](https://github.com/ClickHouse/ClickHouse/pull/19472) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Mark distributed batch as broken in case of empty data block in one of files. [#19449](https://github.com/ClickHouse/ClickHouse/pull/19449) ([Azat Khuzhin](https://github.com/azat)).
+* Fix possible buffer overflow in Uber H3 library. See https://github.com/uber/h3/issues/392. This closes [#19219](https://github.com/ClickHouse/ClickHouse/issues/19219). [#19383](https://github.com/ClickHouse/ClickHouse/pull/19383) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix system.parts _state column (LOGICAL_ERROR when querying this column, due to incorrect order). [#19346](https://github.com/ClickHouse/ClickHouse/pull/19346) ([Azat Khuzhin](https://github.com/azat)).
+* Fix error `Cannot convert column now64() because it is constant but values of constants are different in source and result`. Continuation of [#7156](https://github.com/ClickHouse/ClickHouse/issues/7156). [#19316](https://github.com/ClickHouse/ClickHouse/pull/19316) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug when concurrent `ALTER` and `DROP` queries may hang while processing ReplicatedMergeTree table. [#19237](https://github.com/ClickHouse/ClickHouse/pull/19237) ([alesapin](https://github.com/alesapin)).
+* Fix infinite reading from file in `ORC` format (was introduced in [#10580](https://github.com/ClickHouse/ClickHouse/issues/10580)). Fixes [#19095](https://github.com/ClickHouse/ClickHouse/issues/19095). [#19134](https://github.com/ClickHouse/ClickHouse/pull/19134) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix startup bug when clickhouse was not able to read compression codec from `LowCardinality(Nullable(...))` and throws exception `Attempt to read after EOF`. Fixes [#18340](https://github.com/ClickHouse/ClickHouse/issues/18340). [#19101](https://github.com/ClickHouse/ClickHouse/pull/19101) ([alesapin](https://github.com/alesapin)).
+* Fixed `There is no checkpoint` error when inserting data through http interface using `Template` or `CustomSeparated` format. Fixes [#19021](https://github.com/ClickHouse/ClickHouse/issues/19021). [#19072](https://github.com/ClickHouse/ClickHouse/pull/19072) ([tavplubix](https://github.com/tavplubix)).
+* Restrict `MODIFY TTL` queries for `MergeTree` tables created in old syntax. Previously the query succeeded, but actually it had no effect. [#19064](https://github.com/ClickHouse/ClickHouse/pull/19064) ([Anton Popov](https://github.com/CurtizJ)).
+* Make sure `groupUniqArray` returns correct type for argument of Enum type. This closes [#17875](https://github.com/ClickHouse/ClickHouse/issues/17875). [#19019](https://github.com/ClickHouse/ClickHouse/pull/19019) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible error `Expected single dictionary argument for function` if use function `ignore` with `LowCardinality` argument. Fixes [#14275](https://github.com/ClickHouse/ClickHouse/issues/14275). [#19016](https://github.com/ClickHouse/ClickHouse/pull/19016) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix inserting of `LowCardinality` column to table with `TinyLog` engine. Fixes [#18629](https://github.com/ClickHouse/ClickHouse/issues/18629). [#19010](https://github.com/ClickHouse/ClickHouse/pull/19010) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Disable `optimize_move_functions_out_of_any` because optimization is not always correct. This closes [#18051](https://github.com/ClickHouse/ClickHouse/issues/18051). This closes [#18973](https://github.com/ClickHouse/ClickHouse/issues/18973). [#18981](https://github.com/ClickHouse/ClickHouse/pull/18981) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed very rare deadlock at shutdown. [#18977](https://github.com/ClickHouse/ClickHouse/pull/18977) ([tavplubix](https://github.com/tavplubix)).
+* Fix bug when mutation with some escaped text (like `ALTER ... UPDATE e = CAST('foo', 'Enum8(\'foo\' = 1')` serialized incorrectly. Fixes [#18878](https://github.com/ClickHouse/ClickHouse/issues/18878). [#18944](https://github.com/ClickHouse/ClickHouse/pull/18944) ([alesapin](https://github.com/alesapin)).
+* Attach partition should reset the mutation. [#18804](https://github.com/ClickHouse/ClickHouse/issues/18804). [#18935](https://github.com/ClickHouse/ClickHouse/pull/18935) ([fastio](https://github.com/fastio)).
+* Fix possible hang at shutdown in clickhouse-local. This fixes [#18891](https://github.com/ClickHouse/ClickHouse/issues/18891). [#18893](https://github.com/ClickHouse/ClickHouse/pull/18893) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix *If combinator with unary function and Nullable types. [#18806](https://github.com/ClickHouse/ClickHouse/pull/18806) ([Azat Khuzhin](https://github.com/azat)).
+* Asynchronous distributed INSERTs can be rejected by the server if the setting `network_compression_method` is globally set to non-default value. This fixes [#18741](https://github.com/ClickHouse/ClickHouse/issues/18741). [#18776](https://github.com/ClickHouse/ClickHouse/pull/18776) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `Attempt to read after eof` error when trying to `CAST` `NULL` from `Nullable(String)` to `Nullable(Decimal(P, S))`. Now function `CAST` returns `NULL` when it cannot parse decimal from nullable string. Fixes [#7690](https://github.com/ClickHouse/ClickHouse/issues/7690). [#18718](https://github.com/ClickHouse/ClickHouse/pull/18718) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix Logger with unmatched arg size. [#18717](https://github.com/ClickHouse/ClickHouse/pull/18717) ([sundyli](https://github.com/sundy-li)).
+* Add FixedString Data type support. I'll get this exception "Code: 50, e.displayText() = DB::Exception: Unsupported type FixedString(1)" when replicating data from MySQL to ClickHouse. This patch fixes bug [#18450](https://github.com/ClickHouse/ClickHouse/issues/18450) Also fixes [#6556](https://github.com/ClickHouse/ClickHouse/issues/6556). [#18553](https://github.com/ClickHouse/ClickHouse/pull/18553) ([awesomeleo](https://github.com/awesomeleo)).
+* Fix possible `Pipeline stuck` error while using `ORDER BY` after subquery with `RIGHT` or `FULL` join. [#18550](https://github.com/ClickHouse/ClickHouse/pull/18550) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug which may lead to `ALTER` queries hung after corresponding mutation kill. Found by thread fuzzer. [#18518](https://github.com/ClickHouse/ClickHouse/pull/18518) ([alesapin](https://github.com/alesapin)).
+* Disable write with AIO during merges because it can lead to extremely rare data corruption of primary key columns during merge. [#18481](https://github.com/ClickHouse/ClickHouse/pull/18481) ([alesapin](https://github.com/alesapin)).
+* Disable constant folding for subqueries on the analysis stage, when the result cannot be calculated. [#18446](https://github.com/ClickHouse/ClickHouse/pull/18446) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed `value is too short` error when executing `toType(...)` functions (`toDate`, `toUInt32`, etc) with argument of type `Nullable(String)`. Now such functions return `NULL` on parsing errors instead of throwing exception. Fixes [#7673](https://github.com/ClickHouse/ClickHouse/issues/7673). [#18445](https://github.com/ClickHouse/ClickHouse/pull/18445) ([tavplubix](https://github.com/tavplubix)).
+* Restrict merges from wide to compact parts. In case of vertical merge it led to broken result part. [#18381](https://github.com/ClickHouse/ClickHouse/pull/18381) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix filling table `system.settings_profile_elements`. This PR fixes [#18231](https://github.com/ClickHouse/ClickHouse/issues/18231). [#18379](https://github.com/ClickHouse/ClickHouse/pull/18379) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix index analysis of binary functions with constant argument which leads to wrong query results. This fixes [#18364](https://github.com/ClickHouse/ClickHouse/issues/18364). [#18373](https://github.com/ClickHouse/ClickHouse/pull/18373) ([Amos Bird](https://github.com/amosbird)).
+* Fix possible crashes in aggregate functions with combinator `Distinct`, while using two-level aggregation. Fixes [#17682](https://github.com/ClickHouse/ClickHouse/issues/17682). [#18365](https://github.com/ClickHouse/ClickHouse/pull/18365) ([Anton Popov](https://github.com/CurtizJ)).
+* `SELECT count() FROM table` now can be executed if only one any column can be selected from the `table`. This PR fixes [#10639](https://github.com/ClickHouse/ClickHouse/issues/10639). [#18233](https://github.com/ClickHouse/ClickHouse/pull/18233) ([Vitaly Baranov](https://github.com/vitlibar)).
+* `SELECT JOIN` now requires the `SELECT` privilege on each of the joined tables. This PR fixes [#17654](https://github.com/ClickHouse/ClickHouse/issues/17654). [#18232](https://github.com/ClickHouse/ClickHouse/pull/18232) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix possible incomplete query result while reading from `MergeTree*` in case of read backoff (message `<Debug> MergeTreeReadPool: Will lower number of threads` in logs). Was introduced in [#16423](https://github.com/ClickHouse/ClickHouse/issues/16423). Fixes [#18137](https://github.com/ClickHouse/ClickHouse/issues/18137). [#18216](https://github.com/ClickHouse/ClickHouse/pull/18216) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix error when query `MODIFY COLUMN ... REMOVE TTL` does not actually remove column TTL. [#18130](https://github.com/ClickHouse/ClickHouse/pull/18130) ([alesapin](https://github.com/alesapin)).
+* Fix indeterministic functions with predicate optimizer. This fixes [#17244](https://github.com/ClickHouse/ClickHouse/issues/17244). [#17273](https://github.com/ClickHouse/ClickHouse/pull/17273) ([Winter Zhang](https://github.com/zhang2014)).
+* Mutation might hang waiting for some non-existent part after `MOVE` or `REPLACE PARTITION` or, in rare cases, after `DETACH` or `DROP PARTITION`. It's fixed. [#15537](https://github.com/ClickHouse/ClickHouse/pull/15537) ([tavplubix](https://github.com/tavplubix)).
+
+#### Build/Testing/Packaging Improvement
+
+* Update timezones info to 2020e. [#18531](https://github.com/ClickHouse/ClickHouse/pull/18531) ([alesapin](https://github.com/alesapin)).
+
+
+
+### ClickHouse release v20.11.6.6-stable, 2020-12-24
+
+#### Bug Fix
+
+* Fixed issue when `clickhouse-odbc-bridge` process is unreachable by server on machines with dual `IPv4/IPv6 stack` and fixed issue when ODBC dictionary updates are performed using malformed queries and/or cause crashes. This possibly closes [#14489](https://github.com/ClickHouse/ClickHouse/issues/14489). [#18278](https://github.com/ClickHouse/ClickHouse/pull/18278) ([Denis Glazachev](https://github.com/traceon)).
+* Fixed key comparison between Enum and Int types. This fixes [#17989](https://github.com/ClickHouse/ClickHouse/issues/17989). [#18214](https://github.com/ClickHouse/ClickHouse/pull/18214) ([Amos Bird](https://github.com/amosbird)).
+* Fixed unique key convert crash in `MaterializeMySQL` database engine. This fixes [#18186](https://github.com/ClickHouse/ClickHouse/issues/18186) and fixes [#16372](https://github.com/ClickHouse/ClickHouse/issues/16372)  [#18211](https://github.com/ClickHouse/ClickHouse/pull/18211) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed `std::out_of_range: basic_string` in S3 URL parsing. [#18059](https://github.com/ClickHouse/ClickHouse/pull/18059) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fixed the issue when some tables not synchronized to ClickHouse from MySQL caused by the fact that convertion MySQL prefix index wasn't supported for MaterializeMySQL. This fixes [#15187](https://github.com/ClickHouse/ClickHouse/issues/15187) and fixes [#17912](https://github.com/ClickHouse/ClickHouse/issues/17912)  [#17944](https://github.com/ClickHouse/ClickHouse/pull/17944) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed the issue when query optimization was producing wrong result if query contains `ARRAY JOIN`. [#17887](https://github.com/ClickHouse/ClickHouse/pull/17887) ([sundyli](https://github.com/sundy-li)).
+* Fix possible segfault in `topK` aggregate function. This closes [#17404](https://github.com/ClickHouse/ClickHouse/issues/17404). [#17845](https://github.com/ClickHouse/ClickHouse/pull/17845) ([Maksim Kita](https://github.com/kitaisreal)).
+* Do not restore parts from WAL if `in_memory_parts_enable_wal` is disabled. [#17802](https://github.com/ClickHouse/ClickHouse/pull/17802) ([detailyang](https://github.com/detailyang)).
+* Fixed problem when ClickHouse fails to resume connection to MySQL servers. [#17681](https://github.com/ClickHouse/ClickHouse/pull/17681) ([Alexander Kazakov](https://github.com/Akazz)).
+* Fixed inconsistent behaviour of `optimize_trivial_count_query` with partition predicate. [#17644](https://github.com/ClickHouse/ClickHouse/pull/17644) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed empty `system.stack_trace` table when server is running in daemon mode. [#17630](https://github.com/ClickHouse/ClickHouse/pull/17630) ([Amos Bird](https://github.com/amosbird)).
+* Fixed the behaviour when xxception `fmt::v7::format_error` can be logged in background for MergeTree tables. This fixes [#17613](https://github.com/ClickHouse/ClickHouse/issues/17613). [#17615](https://github.com/ClickHouse/ClickHouse/pull/17615) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the behaviour when clickhouse-client is used in interactive mode with multiline queries and single line comment was erronously extended till the end of query. This fixes [#13654](https://github.com/ClickHouse/ClickHouse/issues/13654). [#17565](https://github.com/ClickHouse/ClickHouse/pull/17565) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the issue when server can stop accepting connections in very rare cases. [#17542](https://github.com/ClickHouse/ClickHouse/pull/17542) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed alter query hang when the corresponding mutation was killed on the different replica. This fixes [#16953](https://github.com/ClickHouse/ClickHouse/issues/16953). [#17499](https://github.com/ClickHouse/ClickHouse/pull/17499) ([alesapin](https://github.com/alesapin)).
+* Fixed bug when mark cache size was underestimated by clickhouse. It may happen when there are a lot of tiny files with marks. [#17496](https://github.com/ClickHouse/ClickHouse/pull/17496) ([alesapin](https://github.com/alesapin)).
+* Fixed `ORDER BY` with enabled setting `optimize_redundant_functions_in_order_by`. [#17471](https://github.com/ClickHouse/ClickHouse/pull/17471) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed duplicates after `DISTINCT` which were possible because of incorrect optimization. This fixes [#17294](https://github.com/ClickHouse/ClickHouse/issues/17294). [#17296](https://github.com/ClickHouse/ClickHouse/pull/17296) ([li chengxiang](https://github.com/chengxianglibra)). [#17439](https://github.com/ClickHouse/ClickHouse/pull/17439) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed crash while reading from `JOIN` table with `LowCardinality` types. This fixes [#17228](https://github.com/ClickHouse/ClickHouse/issues/17228). [#17397](https://github.com/ClickHouse/ClickHouse/pull/17397) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed set index invalidation when there are const columns in the subquery. This fixes [#17246](https://github.com/ClickHouse/ClickHouse/issues/17246) . [#17249](https://github.com/ClickHouse/ClickHouse/pull/17249) ([Amos Bird](https://github.com/amosbird)).
+* Fixed possible wrong index analysis when the types of the index comparison are different. This fixes [#17122](https://github.com/ClickHouse/ClickHouse/issues/17122). [#17145](https://github.com/ClickHouse/ClickHouse/pull/17145) ([Amos Bird](https://github.com/amosbird)).
+* Fixed `ColumnConst` comparison which leads to crash. This fixes [#17088](https://github.com/ClickHouse/ClickHouse/issues/17088) . [#17135](https://github.com/ClickHouse/ClickHouse/pull/17135) ([Amos Bird](https://github.com/amosbird)).
+* Fixed bug when `ON CLUSTER` queries may hang forever for non-leader `ReplicatedMergeTreeTables`. [#17089](https://github.com/ClickHouse/ClickHouse/pull/17089) ([alesapin](https://github.com/alesapin)).
+* Fixed fuzzer-found bug in funciton `fuzzBits`. This fixes [#16980](https://github.com/ClickHouse/ClickHouse/issues/16980). [#17051](https://github.com/ClickHouse/ClickHouse/pull/17051) ([hexiaoting](https://github.com/hexiaoting)).
+* Avoid unnecessary network errors for remote queries which may be cancelled while execution, like queries with `LIMIT`. [#17006](https://github.com/ClickHouse/ClickHouse/pull/17006) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed wrong result in big integers (128, 256 bit) when casting from double. [#16986](https://github.com/ClickHouse/ClickHouse/pull/16986) ([Mike](https://github.com/myrrc)).
+* Reresolve the IP of the `format_avro_schema_registry_url` in case of errors. [#16985](https://github.com/ClickHouse/ClickHouse/pull/16985) ([filimonov](https://github.com/filimonov)).
+* Fixed possible server crash after `ALTER TABLE ... MODIFY COLUMN ... NewType` when `SELECT` have `WHERE` expression on altering column and alter does not finished yet. [#16968](https://github.com/ClickHouse/ClickHouse/pull/16968) ([Amos Bird](https://github.com/amosbird)).
+* Blame info was not calculated correctly in `clickhouse-git-import`. [#16959](https://github.com/ClickHouse/ClickHouse/pull/16959) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed order by optimization with monotonous functions. Fixes [#16107](https://github.com/ClickHouse/ClickHouse/issues/16107). [#16956](https://github.com/ClickHouse/ClickHouse/pull/16956) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed optimization of group by with enabled setting `optimize_aggregators_of_group_by_keys` and joins. This fixes [#12604](https://github.com/ClickHouse/ClickHouse/issues/12604). [#16951](https://github.com/ClickHouse/ClickHouse/pull/16951) ([Anton Popov](https://github.com/CurtizJ)).
+* Install script should always create subdirs in config folders. This is only relevant for Docker build with custom config. [#16936](https://github.com/ClickHouse/ClickHouse/pull/16936) ([filimonov](https://github.com/filimonov)).
+* Fixed possible error `Illegal type of argument` for queries with `ORDER BY`. This fixes [#16580](https://github.com/ClickHouse/ClickHouse/issues/16580). [#16928](https://github.com/ClickHouse/ClickHouse/pull/16928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Abort multipart upload if no data was written to WriteBufferFromS3. [#16840](https://github.com/ClickHouse/ClickHouse/pull/16840) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fixed crash when using `any` without any arguments. This fixes [#16803](https://github.com/ClickHouse/ClickHouse/issues/16803). [#16826](https://github.com/ClickHouse/ClickHouse/pull/16826) ([Amos Bird](https://github.com/amosbird)).
+* Fixed the behaviour when ClickHouse used to always return 0 insted of a number of affected rows for `INSERT` queries via MySQL protocol. This fixes [#16605](https://github.com/ClickHouse/ClickHouse/issues/16605). [#16715](https://github.com/ClickHouse/ClickHouse/pull/16715) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed uncontrolled growth of TDigest. [#16680](https://github.com/ClickHouse/ClickHouse/pull/16680) ([hrissan](https://github.com/hrissan)).
+* Fixed remote query failure when using suffix `if` in Aggregate function. This fixes [#16574](https://github.com/ClickHouse/ClickHouse/issues/16574) fixes [#16231](https://github.com/ClickHouse/ClickHouse/issues/16231) [#16610](https://github.com/ClickHouse/ClickHouse/pull/16610) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed inconsistent behavior caused by `select_sequential_consistency` for optimized trivial count query and system.tables. [#16309](https://github.com/ClickHouse/ClickHouse/pull/16309) ([Hao Chen](https://github.com/haoch)).
+* Throw error when use ColumnTransformer replace non exist column. [#16183](https://github.com/ClickHouse/ClickHouse/pull/16183) ([hexiaoting](https://github.com/hexiaoting)).
+
+
+### ClickHouse release v20.11.3.3-stable, 2020-11-13
+
+#### Bug Fix
+
+* Fix rare silent crashes when query profiler is on and ClickHouse is installed on OS with glibc version that has (supposedly) broken asynchronous unwind tables for some functions. This fixes [#15301](https://github.com/ClickHouse/ClickHouse/issues/15301). This fixes [#13098](https://github.com/ClickHouse/ClickHouse/issues/13098). [#16846](https://github.com/ClickHouse/ClickHouse/pull/16846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+
+### ClickHouse release v20.11.2.1, 2020-11-11
+
+#### Backward Incompatible Change
+
+* If some `profile` was specified in `distributed_ddl` config section, then this profile could overwrite settings of `default` profile on server startup. It's fixed, now settings of distributed DDL queries should not affect global server settings. [#16635](https://github.com/ClickHouse/ClickHouse/pull/16635) ([tavplubix](https://github.com/tavplubix)).
+* Restrict to use of non-comparable data types (like `AggregateFunction`) in keys (Sorting key, Primary key, Partition key, and so on). [#16601](https://github.com/ClickHouse/ClickHouse/pull/16601) ([alesapin](https://github.com/alesapin)).
+* Remove `ANALYZE` and `AST` queries, and make the setting `enable_debug_queries` obsolete since now it is the part of full featured `EXPLAIN` query. [#16536](https://github.com/ClickHouse/ClickHouse/pull/16536) ([Ivan](https://github.com/abyss7)).
+* Aggregate functions `boundingRatio`, `rankCorr`, `retention`, `timeSeriesGroupSum`, `timeSeriesGroupRateSum`, `windowFunnel` were erroneously made case-insensitive. Now their names are made case sensitive as designed. Only functions that are specified in SQL standard or made for compatibility with other DBMS or functions similar to those should be case-insensitive. [#16407](https://github.com/ClickHouse/ClickHouse/pull/16407) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make `rankCorr` function return nan on insufficient data [#16124](https://github.com/ClickHouse/ClickHouse/issues/16124). [#16135](https://github.com/ClickHouse/ClickHouse/pull/16135) ([hexiaoting](https://github.com/hexiaoting)).
+* When upgrading from versions older than 20.5, if rolling update is performed and cluster contains both versions 20.5 or greater and less than 20.5, if ClickHouse nodes with old versions are restarted and old version has been started up in presence of newer versions, it may lead to `Part ... intersects previous part` errors. To prevent this error, first install newer clickhouse-server packages on all cluster nodes and then do restarts (so, when clickhouse-server is restarted, it will start up with the new version).
+
+#### New Feature
+
+* Added support of LDAP as a user directory for locally non-existent users. [#12736](https://github.com/ClickHouse/ClickHouse/pull/12736) ([Denis Glazachev](https://github.com/traceon)).
+* Add `system.replicated_fetches` table which shows currently running background fetches. [#16428](https://github.com/ClickHouse/ClickHouse/pull/16428) ([alesapin](https://github.com/alesapin)).
+* Added setting `date_time_output_format`. [#15845](https://github.com/ClickHouse/ClickHouse/pull/15845) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added minimal web UI to ClickHouse. [#16158](https://github.com/ClickHouse/ClickHouse/pull/16158) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allows to read/write Single protobuf message at once (w/o length-delimiters). [#15199](https://github.com/ClickHouse/ClickHouse/pull/15199) ([filimonov](https://github.com/filimonov)).
+* Added initial OpenTelemetry support. ClickHouse now accepts OpenTelemetry traceparent headers over Native and HTTP protocols, and passes them downstream in some cases. The trace spans for executed queries are saved into the `system.opentelemetry_span_log` table. [#14195](https://github.com/ClickHouse/ClickHouse/pull/14195) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Allow specify primary key in column list of `CREATE TABLE` query. This is needed for compatibility with other SQL dialects. [#15823](https://github.com/ClickHouse/ClickHouse/pull/15823) ([Maksim Kita](https://github.com/kitaisreal)).
+* Implement `OFFSET offset_row_count {ROW | ROWS} FETCH {FIRST | NEXT} fetch_row_count {ROW | ROWS} {ONLY | WITH TIES}` in SELECT query with ORDER BY. This is the SQL-standard way to specify `LIMIT`. [#15855](https://github.com/ClickHouse/ClickHouse/pull/15855) ([hexiaoting](https://github.com/hexiaoting)).
+* `errorCodeToName` function - return variable name of the error (useful for analyzing query_log and similar). `system.errors` table - shows how many times errors has been happened (respects `system_events_show_zero_values`). [#16438](https://github.com/ClickHouse/ClickHouse/pull/16438) ([Azat Khuzhin](https://github.com/azat)).
+* Added function `untuple` which is a special function which can introduce new columns to the SELECT list by expanding a named tuple. [#16242](https://github.com/ClickHouse/ClickHouse/pull/16242) ([Nikolai Kochetov](https://github.com/KochetovNicolai), [Amos Bird](https://github.com/amosbird)).
+* Now we can provide identifiers via query parameters. And these parameters can be used as table objects or columns. [#16594](https://github.com/ClickHouse/ClickHouse/pull/16594) ([Amos Bird](https://github.com/amosbird)).
+* Added big integers (UInt256, Int128, Int256) and UUID data types support for MergeTree BloomFilter index. Big integers is an experimental feature. [#16642](https://github.com/ClickHouse/ClickHouse/pull/16642) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add `farmFingerprint64` function (non-cryptographic string hashing). [#16570](https://github.com/ClickHouse/ClickHouse/pull/16570) ([Jacob Hayes](https://github.com/JacobHayes)).
+* Add `log_queries_min_query_duration_ms`, only queries slower than the value of this setting will go to `query_log`/`query_thread_log` (i.e. something like `slow_query_log` in mysql). [#16529](https://github.com/ClickHouse/ClickHouse/pull/16529) ([Azat Khuzhin](https://github.com/azat)).
+* Ability to create a docker image on the top of `Alpine`. Uses precompiled binary and glibc components from ubuntu 20.04. [#16479](https://github.com/ClickHouse/ClickHouse/pull/16479) ([filimonov](https://github.com/filimonov)).
+* Added `toUUIDOrNull`, `toUUIDOrZero` cast functions. [#16337](https://github.com/ClickHouse/ClickHouse/pull/16337) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add `max_concurrent_queries_for_all_users` setting, see [#6636](https://github.com/ClickHouse/ClickHouse/issues/6636) for use cases. [#16154](https://github.com/ClickHouse/ClickHouse/pull/16154) ([nvartolomei](https://github.com/nvartolomei)).
+* Add a new option `print_query_id` to clickhouse-client. It helps generate arbitrary strings with the current query id generated by the client. Also print query id in clickhouse-client by default. [#15809](https://github.com/ClickHouse/ClickHouse/pull/15809) ([Amos Bird](https://github.com/amosbird)).
+* Add `tid` and `logTrace` functions. This closes [#9434](https://github.com/ClickHouse/ClickHouse/issues/9434). [#15803](https://github.com/ClickHouse/ClickHouse/pull/15803) ([flynn](https://github.com/ucasFL)).
+* Add function `formatReadableTimeDelta` that format time delta to human readable string ... [#15497](https://github.com/ClickHouse/ClickHouse/pull/15497) ([Filipe Caixeta](https://github.com/filipecaixeta)).
+* Added `disable_merges` option for volumes in multi-disk configuration. [#13956](https://github.com/ClickHouse/ClickHouse/pull/13956) ([Vladimir Chebotarev](https://github.com/excitoon)).
+
+#### Experimental Feature
+
+* New functions `encrypt`, `aes_encrypt_mysql`, `decrypt`, `aes_decrypt_mysql`. These functions are working slowly, so we consider it as an experimental feature. [#11844](https://github.com/ClickHouse/ClickHouse/pull/11844) ([Vasily Nemkov](https://github.com/Enmk)).
+
+#### Bug Fix
+
+* Mask password in data_path in the `system.distribution_queue`. [#16727](https://github.com/ClickHouse/ClickHouse/pull/16727) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `IN` operator over several columns and tuples with enabled `transform_null_in` setting. Fixes [#15310](https://github.com/ClickHouse/ClickHouse/issues/15310). [#16722](https://github.com/ClickHouse/ClickHouse/pull/16722) ([Anton Popov](https://github.com/CurtizJ)).
+* The setting `max_parallel_replicas` worked incorrectly if the queried table has no sampling. This fixes [#5733](https://github.com/ClickHouse/ClickHouse/issues/5733). [#16675](https://github.com/ClickHouse/ClickHouse/pull/16675) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix optimize_read_in_order/optimize_aggregation_in_order with max_threads > 0 and expression in ORDER BY. [#16637](https://github.com/ClickHouse/ClickHouse/pull/16637) ([Azat Khuzhin](https://github.com/azat)).
+* Calculation of `DEFAULT` expressions was involving possible name collisions (that was very unlikely to encounter). This fixes [#9359](https://github.com/ClickHouse/ClickHouse/issues/9359). [#16612](https://github.com/ClickHouse/ClickHouse/pull/16612) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `query_thread_log.query_duration_ms` unit. [#16563](https://github.com/ClickHouse/ClickHouse/pull/16563) ([Azat Khuzhin](https://github.com/azat)).
+* Fix a bug when using MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL Engine. `MaterializeMySQL` is an experimental feature. [#16504](https://github.com/ClickHouse/ClickHouse/pull/16504) ([TCeason](https://github.com/TCeason)).
+* Specifically crafted argument of `round` function with `Decimal` was leading to integer division by zero. This fixes [#13338](https://github.com/ClickHouse/ClickHouse/issues/13338). [#16451](https://github.com/ClickHouse/ClickHouse/pull/16451) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix DROP TABLE for Distributed (racy with INSERT). [#16409](https://github.com/ClickHouse/ClickHouse/pull/16409) ([Azat Khuzhin](https://github.com/azat)).
+* Fix processing of very large entries in replication queue. Very large entries may appear in ALTER queries if table structure is extremely large (near 1 MB). This fixes [#16307](https://github.com/ClickHouse/ClickHouse/issues/16307). [#16332](https://github.com/ClickHouse/ClickHouse/pull/16332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the inconsistent behaviour when a part of return data could be dropped because the set for its filtration wasn't created. [#16308](https://github.com/ClickHouse/ClickHouse/pull/16308) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix dictGet in sharding_key (and similar places, i.e. when the function context is stored permanently). [#16205](https://github.com/ClickHouse/ClickHouse/pull/16205) ([Azat Khuzhin](https://github.com/azat)).
+* Fix the exception thrown in `clickhouse-local` when trying to execute `OPTIMIZE` command. Fixes [#16076](https://github.com/ClickHouse/ClickHouse/issues/16076). [#16192](https://github.com/ClickHouse/ClickHouse/pull/16192) ([filimonov](https://github.com/filimonov)).
+* Fixes [#15780](https://github.com/ClickHouse/ClickHouse/issues/15780) regression, e.g. `indexOf([1, 2, 3], toLowCardinality(1))` now is prohibited but it should not be. [#16038](https://github.com/ClickHouse/ClickHouse/pull/16038) ([Mike](https://github.com/myrrc)).
+* Fix bug with MySQL database. When MySQL server used as database engine is down some queries raise Exception, because they try to get tables from disabled server, while it's unnecessary. For example, query `SELECT ... FROM system.parts` should work only with MergeTree tables and don't touch MySQL database at all. [#16032](https://github.com/ClickHouse/ClickHouse/pull/16032) ([Kruglov Pavel](https://github.com/Avogar)).
+* Now exception will be thrown when `ALTER MODIFY COLUMN ... DEFAULT ...` has incompatible default with column type. Fixes [#15854](https://github.com/ClickHouse/ClickHouse/issues/15854). [#15858](https://github.com/ClickHouse/ClickHouse/pull/15858) ([alesapin](https://github.com/alesapin)).
+* Fixed IPv4CIDRToRange/IPv6CIDRToRange functions to accept const IP-column values. [#15856](https://github.com/ClickHouse/ClickHouse/pull/15856) ([vladimir-golovchenko](https://github.com/vladimir-golovchenko)).
+
+#### Improvement
+
+* Treat `INTERVAL '1 hour'` as equivalent to `INTERVAL 1 HOUR`, to be compatible with Postgres and similar. This fixes [#15637](https://github.com/ClickHouse/ClickHouse/issues/15637). [#15978](https://github.com/ClickHouse/ClickHouse/pull/15978) ([flynn](https://github.com/ucasFL)).
+* Enable parsing enum values by their numeric ids for CSV, TSV and JSON input formats. [#15685](https://github.com/ClickHouse/ClickHouse/pull/15685) ([vivarum](https://github.com/vivarum)).
+* Better read task scheduling for JBOD architecture and `MergeTree` storage. New setting `read_backoff_min_concurrency` which serves as the lower limit to the number of reading threads. [#16423](https://github.com/ClickHouse/ClickHouse/pull/16423) ([Amos Bird](https://github.com/amosbird)).
+* Add missing support for `LowCardinality` in `Avro` format. [#16521](https://github.com/ClickHouse/ClickHouse/pull/16521) ([Mike](https://github.com/myrrc)).
+* Workaround for use `S3` with nginx server as proxy. Nginx currenty does not accept urls with empty path like `http://domain.com?delete`, but vanilla aws-sdk-cpp produces this kind of urls. This commit uses patched aws-sdk-cpp version, which makes urls with "/" as path in this cases, like `http://domain.com/?delete`. [#16814](https://github.com/ClickHouse/ClickHouse/pull/16814) ([ianton-ru](https://github.com/ianton-ru)).
+* Better diagnostics on parse errors in input data. Provide row number on `Cannot read all data` errors. [#16644](https://github.com/ClickHouse/ClickHouse/pull/16644) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make the behaviour of `minMap` and `maxMap` more desireable. It will not skip zero values in the result. Fixes [#16087](https://github.com/ClickHouse/ClickHouse/issues/16087). [#16631](https://github.com/ClickHouse/ClickHouse/pull/16631) ([Ildus Kurbangaliev](https://github.com/ildus)).
+* Better update of ZooKeeper configuration in runtime. [#16630](https://github.com/ClickHouse/ClickHouse/pull/16630) ([sundyli](https://github.com/sundy-li)).
+* Apply SETTINGS clause as early as possible. It allows to modify more settings in the query. This closes [#3178](https://github.com/ClickHouse/ClickHouse/issues/3178). [#16619](https://github.com/ClickHouse/ClickHouse/pull/16619) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now `event_time_microseconds` field stores in Decimal64, not UInt64. [#16617](https://github.com/ClickHouse/ClickHouse/pull/16617) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Now paratmeterized functions can be used in `APPLY` column transformer. [#16589](https://github.com/ClickHouse/ClickHouse/pull/16589) ([Amos Bird](https://github.com/amosbird)).
+* Improve scheduling of background task which removes data of dropped tables in `Atomic` databases. `Atomic` databases do not create broken symlink to table data directory if table actually has no data directory. [#16584](https://github.com/ClickHouse/ClickHouse/pull/16584) ([tavplubix](https://github.com/tavplubix)).
+* Subqueries in `WITH` section (CTE) can reference previous subqueries in `WITH` section by their name. [#16575](https://github.com/ClickHouse/ClickHouse/pull/16575) ([Amos Bird](https://github.com/amosbird)).
+* Add current_database into `system.query_thread_log`. [#16558](https://github.com/ClickHouse/ClickHouse/pull/16558) ([Azat Khuzhin](https://github.com/azat)).
+* Allow to fetch parts that are already committed or outdated in the current instance into the detached directory. It's useful when migrating tables from another cluster and having N to 1 shards mapping. It's also consistent with the current fetchPartition implementation. [#16538](https://github.com/ClickHouse/ClickHouse/pull/16538) ([Amos Bird](https://github.com/amosbird)).
+* Multiple improvements for `RabbitMQ`: Fixed bug for [#16263](https://github.com/ClickHouse/ClickHouse/issues/16263). Also minimized event loop lifetime. Added more efficient queues setup. [#16426](https://github.com/ClickHouse/ClickHouse/pull/16426) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix debug assertion in `quantileDeterministic` function. In previous version it may also transfer up to two times more data over the network. Although no bug existed. This fixes [#15683](https://github.com/ClickHouse/ClickHouse/issues/15683). [#16410](https://github.com/ClickHouse/ClickHouse/pull/16410) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add `TablesToDropQueueSize` metric. It's equal to number of dropped tables, that are waiting for background data removal. [#16364](https://github.com/ClickHouse/ClickHouse/pull/16364) ([tavplubix](https://github.com/tavplubix)).
+* Better diagnostics when client has dropped connection. In previous versions, `Attempt to read after EOF` and `Broken pipe` exceptions were logged in server. In new version, it's information message `Client has dropped the connection, cancel the query.`. [#16329](https://github.com/ClickHouse/ClickHouse/pull/16329) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add total_rows/total_bytes (from system.tables) support for Set/Join table engines. [#16306](https://github.com/ClickHouse/ClickHouse/pull/16306) ([Azat Khuzhin](https://github.com/azat)).
+* Now it's possible to specify `PRIMARY KEY` without `ORDER BY` for MergeTree table engines family. Closes [#15591](https://github.com/ClickHouse/ClickHouse/issues/15591). [#16284](https://github.com/ClickHouse/ClickHouse/pull/16284) ([alesapin](https://github.com/alesapin)).
+* If there is no tmp folder in the system (chroot, misconfigutation etc) `clickhouse-local` will create temporary subfolder in the current directory. [#16280](https://github.com/ClickHouse/ClickHouse/pull/16280) ([filimonov](https://github.com/filimonov)).
+* Add support for nested data types (like named tuple) as sub-types. Fixes [#15587](https://github.com/ClickHouse/ClickHouse/issues/15587). [#16262](https://github.com/ClickHouse/ClickHouse/pull/16262) ([Ivan](https://github.com/abyss7)).
+* Support for `database_atomic_wait_for_drop_and_detach_synchronously`/`NO DELAY`/`SYNC` for `DROP DATABASE`. [#16127](https://github.com/ClickHouse/ClickHouse/pull/16127) ([Azat Khuzhin](https://github.com/azat)).
+* Add `allow_nondeterministic_optimize_skip_unused_shards` (to allow non deterministic like `rand()` or `dictGet()` in sharding key). [#16105](https://github.com/ClickHouse/ClickHouse/pull/16105) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `memory_profiler_step`/`max_untracked_memory` for queries via HTTP (test included). Fix the issue that adjusting this value globally in xml config does not help either, since those settings are not applied anyway, only default (4MB) value is [used](https://github.com/ClickHouse/ClickHouse/blob/17731245336d8c84f75e4c0894c5797ed7732190/src/Common/ThreadStatus.h#L104). Fix `query_id` for the most root ThreadStatus of the http query (by initializing QueryScope after reading query_id). [#16101](https://github.com/ClickHouse/ClickHouse/pull/16101) ([Azat Khuzhin](https://github.com/azat)).
+* Now it's allowed to execute `ALTER ... ON CLUSTER` queries regardless of the `<internal_replication>` setting in cluster config. [#16075](https://github.com/ClickHouse/ClickHouse/pull/16075) ([alesapin](https://github.com/alesapin)).
+* Fix rare issue when `clickhouse-client` may abort on exit due to loading of suggestions. This fixes [#16035](https://github.com/ClickHouse/ClickHouse/issues/16035). [#16047](https://github.com/ClickHouse/ClickHouse/pull/16047) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add support of `cache` layout for `Redis` dictionaries with complex key. [#15985](https://github.com/ClickHouse/ClickHouse/pull/15985) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix query hang (endless loop) in case of misconfiguration (`connections_with_failover_max_tries` set to 0). [#15876](https://github.com/ClickHouse/ClickHouse/pull/15876) ([Azat Khuzhin](https://github.com/azat)).
+* Change level of some log messages from information to debug, so information messages will not appear for every query. This closes [#5293](https://github.com/ClickHouse/ClickHouse/issues/5293). [#15816](https://github.com/ClickHouse/ClickHouse/pull/15816) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove `MemoryTrackingInBackground*` metrics to avoid potentially misleading results. This fixes [#15684](https://github.com/ClickHouse/ClickHouse/issues/15684). [#15813](https://github.com/ClickHouse/ClickHouse/pull/15813) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add reconnects to `zookeeper-dump-tree` tool. [#15711](https://github.com/ClickHouse/ClickHouse/pull/15711) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow explicitly specify columns list in `CREATE TABLE table AS table_function(...)` query. Fixes [#9249](https://github.com/ClickHouse/ClickHouse/issues/9249) Fixes [#14214](https://github.com/ClickHouse/ClickHouse/issues/14214). [#14295](https://github.com/ClickHouse/ClickHouse/pull/14295) ([tavplubix](https://github.com/tavplubix)).
+
+#### Performance Improvement
+
+* Do not merge parts across partitions in SELECT FINAL. [#15938](https://github.com/ClickHouse/ClickHouse/pull/15938) ([Kruglov Pavel](https://github.com/Avogar)).
+* Improve performance of `-OrNull` and `-OrDefault` aggregate functions. [#16661](https://github.com/ClickHouse/ClickHouse/pull/16661) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve performance of `quantileMerge`. In previous versions it was obnoxiously slow. This closes [#1463](https://github.com/ClickHouse/ClickHouse/issues/1463). [#16643](https://github.com/ClickHouse/ClickHouse/pull/16643) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve performance of logical functions a little. [#16347](https://github.com/ClickHouse/ClickHouse/pull/16347) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improved performance of merges assignment in MergeTree table engines. Shouldn't be visible for the user. [#16191](https://github.com/ClickHouse/ClickHouse/pull/16191) ([alesapin](https://github.com/alesapin)).
+* Speedup hashed/sparse_hashed dictionary loading by preallocating the hash table. [#15454](https://github.com/ClickHouse/ClickHouse/pull/15454) ([Azat Khuzhin](https://github.com/azat)).
+* Now trivial count optimization becomes slightly non-trivial. Predicates that contain exact partition expr can be optimized too. This also fixes [#11092](https://github.com/ClickHouse/ClickHouse/issues/11092) which returns wrong count when `max_parallel_replicas > 1`. [#15074](https://github.com/ClickHouse/ClickHouse/pull/15074) ([Amos Bird](https://github.com/amosbird)).
+
+#### Build/Testing/Packaging Improvement
+
+* Add flaky check for stateless tests. It will detect potentially flaky functional tests in advance, before they are merged. [#16238](https://github.com/ClickHouse/ClickHouse/pull/16238) ([alesapin](https://github.com/alesapin)).
+* Use proper version for `croaring` instead of amalgamation. [#16285](https://github.com/ClickHouse/ClickHouse/pull/16285) ([sundyli](https://github.com/sundy-li)).
+* Improve generation of build files for `ya.make` build system (Arcadia). [#16700](https://github.com/ClickHouse/ClickHouse/pull/16700) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add MySQL BinLog file check tool for `MaterializeMySQL` database engine. `MaterializeMySQL` is an experimental feature. [#16223](https://github.com/ClickHouse/ClickHouse/pull/16223) ([Winter Zhang](https://github.com/zhang2014)).
+* Check for executable bit on non-executable files. People often accidentially commit executable files from Windows. [#15843](https://github.com/ClickHouse/ClickHouse/pull/15843) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Check for `#pragma once` in headers. [#15818](https://github.com/ClickHouse/ClickHouse/pull/15818) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix illegal code style `&vector[idx]` in libhdfs3. This fixes libcxx debug build. See also https://github.com/ClickHouse-Extras/libhdfs3/pull/8 . [#15815](https://github.com/ClickHouse/ClickHouse/pull/15815) ([Amos Bird](https://github.com/amosbird)).
+* Fix build of one miscellaneous example tool on Mac OS. Note that we don't build examples on Mac OS in our CI (we build only ClickHouse binary), so there is zero chance it will not break again. This fixes [#15804](https://github.com/ClickHouse/ClickHouse/issues/15804). [#15808](https://github.com/ClickHouse/ClickHouse/pull/15808) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Simplify Sys/V init script. [#14135](https://github.com/ClickHouse/ClickHouse/pull/14135) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added `boost::program_options` to `db_generator` in order to increase its usability. This closes [#15940](https://github.com/ClickHouse/ClickHouse/issues/15940). [#15973](https://github.com/ClickHouse/ClickHouse/pull/15973) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+
+
+## ClickHouse release 20.10
+
+### ClickHouse release v20.10.7.4-stable, 2020-12-24
+
+#### Bug Fix
+
+* Fixed issue when `clickhouse-odbc-bridge` process is unreachable by server on machines with dual `IPv4/IPv6` stack and fixed issue when ODBC dictionary updates are performed using malformed queries and/or cause crashes. This possibly closes [#14489](https://github.com/ClickHouse/ClickHouse/issues/14489). [#18278](https://github.com/ClickHouse/ClickHouse/pull/18278) ([Denis Glazachev](https://github.com/traceon)).
+* Fix key comparison between Enum and Int types. This fixes [#17989](https://github.com/ClickHouse/ClickHouse/issues/17989). [#18214](https://github.com/ClickHouse/ClickHouse/pull/18214) ([Amos Bird](https://github.com/amosbird)).
+* Fixed unique key convert crash in `MaterializeMySQL` database engine. This fixes [#18186](https://github.com/ClickHouse/ClickHouse/issues/18186) and fixes [#16372](https://github.com/ClickHouse/ClickHouse/issues/16372)  [#18211](https://github.com/ClickHouse/ClickHouse/pull/18211) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed `std::out_of_range: basic_string` in S3 URL parsing. [#18059](https://github.com/ClickHouse/ClickHouse/pull/18059) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fixed the issue when some tables not synchronized to ClickHouse from MySQL caused by the fact that convertion MySQL prefix index wasn't supported for MaterializeMySQL. This fixes [#15187](https://github.com/ClickHouse/ClickHouse/issues/15187) and fixes [#17912](https://github.com/ClickHouse/ClickHouse/issues/17912)  [#17944](https://github.com/ClickHouse/ClickHouse/pull/17944) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix possible segfault in `topK` aggregate function. This closes [#17404](https://github.com/ClickHouse/ClickHouse/issues/17404). [#17845](https://github.com/ClickHouse/ClickHouse/pull/17845) ([Maksim Kita](https://github.com/kitaisreal)).
+* Do not restore parts from `WAL` if `in_memory_parts_enable_wal` is disabled. [#17802](https://github.com/ClickHouse/ClickHouse/pull/17802) ([detailyang](https://github.com/detailyang)).
+* Fixed problem when ClickHouse fails to resume connection to MySQL servers. [#17681](https://github.com/ClickHouse/ClickHouse/pull/17681) ([Alexander Kazakov](https://github.com/Akazz)).
+* Fixed empty `system.stack_trace` table when server is running in daemon mode. [#17630](https://github.com/ClickHouse/ClickHouse/pull/17630) ([Amos Bird](https://github.com/amosbird)).
+* Fixed the behaviour when `clickhouse-client` is used in interactive mode with multiline queries and single line comment was erronously extended till the end of query. This fixes [#13654](https://github.com/ClickHouse/ClickHouse/issues/13654). [#17565](https://github.com/ClickHouse/ClickHouse/pull/17565) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the issue when server can stop accepting connections in very rare cases. [#17542](https://github.com/ClickHouse/ClickHouse/pull/17542) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `ALTER` query hang when the corresponding mutation was killed on the different replica. This fixes [#16953](https://github.com/ClickHouse/ClickHouse/issues/16953). [#17499](https://github.com/ClickHouse/ClickHouse/pull/17499) ([alesapin](https://github.com/alesapin)).
+* Fixed bug when mark cache size was underestimated by clickhouse. It may happen when there are a lot of tiny files with marks. [#17496](https://github.com/ClickHouse/ClickHouse/pull/17496) ([alesapin](https://github.com/alesapin)).
+* Fixed `ORDER BY` with enabled setting `optimize_redundant_functions_in_order_by`. [#17471](https://github.com/ClickHouse/ClickHouse/pull/17471) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed duplicates after `DISTINCT` which were possible because of incorrect optimization. Fixes [#17294](https://github.com/ClickHouse/ClickHouse/issues/17294). [#17296](https://github.com/ClickHouse/ClickHouse/pull/17296) ([li chengxiang](https://github.com/chengxianglibra)). [#17439](https://github.com/ClickHouse/ClickHouse/pull/17439) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed crash while reading from `JOIN` table with `LowCardinality` types. This fixes [#17228](https://github.com/ClickHouse/ClickHouse/issues/17228). [#17397](https://github.com/ClickHouse/ClickHouse/pull/17397) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed set index invalidation when there are const columns in the subquery. This fixes [#17246](https://github.com/ClickHouse/ClickHouse/issues/17246) . [#17249](https://github.com/ClickHouse/ClickHouse/pull/17249) ([Amos Bird](https://github.com/amosbird)).
+* Fixed `ColumnConst` comparison which leads to crash. This fixed [#17088](https://github.com/ClickHouse/ClickHouse/issues/17088) . [#17135](https://github.com/ClickHouse/ClickHouse/pull/17135) ([Amos Bird](https://github.com/amosbird)).
+* Fixed bug when `ON CLUSTER` queries may hang forever for non-leader `ReplicatedMergeTreeTables`. [#17089](https://github.com/ClickHouse/ClickHouse/pull/17089) ([alesapin](https://github.com/alesapin)).
+* Fixed fuzzer-found bug in function `fuzzBits`. This fixes [#16980](https://github.com/ClickHouse/ClickHouse/issues/16980). [#17051](https://github.com/ClickHouse/ClickHouse/pull/17051) ([hexiaoting](https://github.com/hexiaoting)).
+* Avoid unnecessary network errors for remote queries which may be cancelled while execution, like queries with `LIMIT`. [#17006](https://github.com/ClickHouse/ClickHouse/pull/17006) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed wrong result in big integers (128, 256 bit) when casting from double. [#16986](https://github.com/ClickHouse/ClickHouse/pull/16986) ([Mike](https://github.com/myrrc)).
+* Reresolve the IP of the `format_avro_schema_registry_url` in case of errors. [#16985](https://github.com/ClickHouse/ClickHouse/pull/16985) ([filimonov](https://github.com/filimonov)).
+* Fixed possible server crash after `ALTER TABLE ... MODIFY COLUMN ... NewType` when `SELECT` have `WHERE` expression on altering column and alter does not finished yet. [#16968](https://github.com/ClickHouse/ClickHouse/pull/16968) ([Amos Bird](https://github.com/amosbird)).
+* Blame info was not calculated correctly in `clickhouse-git-import`. [#16959](https://github.com/ClickHouse/ClickHouse/pull/16959) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed order by optimization with monotonous functions. This fixes [#16107](https://github.com/ClickHouse/ClickHouse/issues/16107). [#16956](https://github.com/ClickHouse/ClickHouse/pull/16956) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixrf optimization of group by with enabled setting `optimize_aggregators_of_group_by_keys` and joins. This fixes [#12604](https://github.com/ClickHouse/ClickHouse/issues/12604). [#16951](https://github.com/ClickHouse/ClickHouse/pull/16951) ([Anton Popov](https://github.com/CurtizJ)).
+* Install script should always create subdirs in config folders. This is only relevant for Docker build with custom config. [#16936](https://github.com/ClickHouse/ClickHouse/pull/16936) ([filimonov](https://github.com/filimonov)).
+* Fixrf possible error `Illegal type of argument` for queries with `ORDER BY`. This fixes [#16580](https://github.com/ClickHouse/ClickHouse/issues/16580). [#16928](https://github.com/ClickHouse/ClickHouse/pull/16928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Abort multipart upload if no data was written to `WriteBufferFromS3`. [#16840](https://github.com/ClickHouse/ClickHouse/pull/16840) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fixed crash when using `any` without any arguments. This fixes [#16803](https://github.com/ClickHouse/ClickHouse/issues/16803). [#16826](https://github.com/ClickHouse/ClickHouse/pull/16826) ([Amos Bird](https://github.com/amosbird)).
+* Fixed the behaviour when ClickHouse used to always return 0 insted of a number of affected rows for `INSERT` queries via MySQL protocol. This fixes [#16605](https://github.com/ClickHouse/ClickHouse/issues/16605). [#16715](https://github.com/ClickHouse/ClickHouse/pull/16715) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed uncontrolled growth of `TDigest`. [#16680](https://github.com/ClickHouse/ClickHouse/pull/16680) ([hrissan](https://github.com/hrissan)).
+* Fixed remote query failure when using suffix `if` in Aggregate function. This fixes [#16574](https://github.com/ClickHouse/ClickHouse/issues/16574) fixes [#16231](https://github.com/ClickHouse/ClickHouse/issues/16231) [#16610](https://github.com/ClickHouse/ClickHouse/pull/16610) ([Winter Zhang](https://github.com/zhang2014)).
+
+
+### ClickHouse release v20.10.4.1-stable, 2020-11-13
+
+#### Bug Fix
+
+* Fix rare silent crashes when query profiler is on and ClickHouse is installed on OS with glibc version that has (supposedly) broken asynchronous unwind tables for some functions. This fixes [#15301](https://github.com/ClickHouse/ClickHouse/issues/15301). This fixes [#13098](https://github.com/ClickHouse/ClickHouse/issues/13098). [#16846](https://github.com/ClickHouse/ClickHouse/pull/16846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `IN` operator over several columns and tuples with enabled `transform_null_in` setting. Fixes [#15310](https://github.com/ClickHouse/ClickHouse/issues/15310). [#16722](https://github.com/ClickHouse/ClickHouse/pull/16722) ([Anton Popov](https://github.com/CurtizJ)).
+* This will fix optimize_read_in_order/optimize_aggregation_in_order with max_threads>0 and expression in ORDER BY. [#16637](https://github.com/ClickHouse/ClickHouse/pull/16637) ([Azat Khuzhin](https://github.com/azat)).
+* Now when parsing AVRO from input the LowCardinality is removed from type. Fixes [#16188](https://github.com/ClickHouse/ClickHouse/issues/16188). [#16521](https://github.com/ClickHouse/ClickHouse/pull/16521) ([Mike](https://github.com/myrrc)).
+* Fix rapid growth of metadata when using MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL Engine, and `slave_parallel_worker` enabled on MySQL Slave, by properly shrinking GTID sets. This fixes [#15951](https://github.com/ClickHouse/ClickHouse/issues/15951). [#16504](https://github.com/ClickHouse/ClickHouse/pull/16504) ([TCeason](https://github.com/TCeason)).
+* Fix DROP TABLE for Distributed (racy with INSERT). [#16409](https://github.com/ClickHouse/ClickHouse/pull/16409) ([Azat Khuzhin](https://github.com/azat)).
+* Fix processing of very large entries in replication queue. Very large entries may appear in ALTER queries if table structure is extremely large (near 1 MB). This fixes [#16307](https://github.com/ClickHouse/ClickHouse/issues/16307). [#16332](https://github.com/ClickHouse/ClickHouse/pull/16332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bug with MySQL database. When MySQL server used as database engine is down some queries raise Exception, because they try to get tables from disabled server, while it's unnecessary. For example, query `SELECT ... FROM system.parts` should work only with MergeTree tables and don't touch MySQL database at all. [#16032](https://github.com/ClickHouse/ClickHouse/pull/16032) ([Kruglov Pavel](https://github.com/Avogar)).
+
+#### Improvement
+
+* Workaround for use S3 with nginx server as proxy. Nginx currenty does not accept urls with empty path like http://domain.com?delete, but vanilla aws-sdk-cpp produces this kind of urls. This commit uses patched aws-sdk-cpp version, which makes urls with "/" as path in this cases, like http://domain.com/?delete. [#16813](https://github.com/ClickHouse/ClickHouse/pull/16813) ([ianton-ru](https://github.com/ianton-ru)).
+
+
+### ClickHouse release v20.10.3.30, 2020-10-28
+
+#### Backward Incompatible Change
+
+* Make `multiple_joins_rewriter_version` obsolete. Remove first version of joins rewriter. [#15472](https://github.com/ClickHouse/ClickHouse/pull/15472) ([Artem Zuikov](https://github.com/4ertus2)).
+* Change default value of `format_regexp_escaping_rule` setting (it's related to `Regexp` format) to `Raw` (it means - read whole subpattern as a value) to make the behaviour more like to what users expect. [#15426](https://github.com/ClickHouse/ClickHouse/pull/15426) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add support for nested multiline comments `/* comment /* comment */ */` in SQL. This conforms to the SQL standard. [#14655](https://github.com/ClickHouse/ClickHouse/pull/14655) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added MergeTree settings (`max_replicated_merges_with_ttl_in_queue` and `max_number_of_merges_with_ttl_in_pool`) to control the number of merges with TTL in the background pool and replicated queue. This change breaks compatibility with older versions only if you use delete TTL. Otherwise, replication will stay compatible. You can avoid incompatibility issues if you update all shard replicas at once or execute `SYSTEM STOP TTL MERGES` until you finish the update of all replicas. If you'll get an incompatible entry in the replication queue, first of all, execute `SYSTEM STOP TTL MERGES` and after `ALTER TABLE ... DETACH PARTITION ...` the partition where incompatible TTL merge was assigned. Attach it back on a single replica. [#14490](https://github.com/ClickHouse/ClickHouse/pull/14490) ([alesapin](https://github.com/alesapin)).
+* When upgrading from versions older than 20.5, if rolling update is performed and cluster contains both versions 20.5 or greater and less than 20.5, if ClickHouse nodes with old versions are restarted and old version has been started up in presence of newer versions, it may lead to `Part ... intersects previous part` errors. To prevent this error, first install newer clickhouse-server packages on all cluster nodes and then do restarts (so, when clickhouse-server is restarted, it will start up with the new version).
+
+#### New Feature
+
+* Background data recompression. Add the ability to specify `TTL ... RECOMPRESS codec_name` for MergeTree table engines family. [#14494](https://github.com/ClickHouse/ClickHouse/pull/14494) ([alesapin](https://github.com/alesapin)).
+* Add parallel quorum inserts. This closes [#15601](https://github.com/ClickHouse/ClickHouse/issues/15601). [#15601](https://github.com/ClickHouse/ClickHouse/pull/15601) ([Latysheva Alexandra](https://github.com/alexelex)).
+* Settings for additional enforcement of data durability. Useful for non-replicated setups. [#11948](https://github.com/ClickHouse/ClickHouse/pull/11948) ([Anton Popov](https://github.com/CurtizJ)).
+* When duplicate block is written to replica where it does not exist locally (has not been fetched from replicas), don't ignore it and write locally to achieve the same effect as if it was successfully replicated. [#11684](https://github.com/ClickHouse/ClickHouse/pull/11684) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now we support `WITH <identifier> AS (subquery) ... ` to introduce named subqueries in the query context. This closes [#2416](https://github.com/ClickHouse/ClickHouse/issues/2416). This closes [#4967](https://github.com/ClickHouse/ClickHouse/issues/4967). [#14771](https://github.com/ClickHouse/ClickHouse/pull/14771) ([Amos Bird](https://github.com/amosbird)).
+* Introduce `enable_global_with_statement` setting which propagates the first select's `WITH` statements to other select queries at the same level, and makes aliases in `WITH` statements visible to subqueries. [#15451](https://github.com/ClickHouse/ClickHouse/pull/15451) ([Amos Bird](https://github.com/amosbird)).
+* Secure inter-cluster query execution (with initial_user as current query user). [#13156](https://github.com/ClickHouse/ClickHouse/pull/13156) ([Azat Khuzhin](https://github.com/azat)). [#15551](https://github.com/ClickHouse/ClickHouse/pull/15551) ([Azat Khuzhin](https://github.com/azat)).
+* Add the ability to remove column properties and table TTLs. Introduced queries `ALTER TABLE MODIFY COLUMN col_name REMOVE what_to_remove` and `ALTER TABLE REMOVE TTL`. Both operations are lightweight and executed at the metadata level. [#14742](https://github.com/ClickHouse/ClickHouse/pull/14742) ([alesapin](https://github.com/alesapin)).
+* Added format `RawBLOB`. It is intended for input or output a single value without any escaping and delimiters. This closes [#15349](https://github.com/ClickHouse/ClickHouse/issues/15349). [#15364](https://github.com/ClickHouse/ClickHouse/pull/15364) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add the `reinterpretAsUUID` function that allows to convert a big-endian byte string to UUID. [#15480](https://github.com/ClickHouse/ClickHouse/pull/15480) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Implement `force_data_skipping_indices` setting. [#15642](https://github.com/ClickHouse/ClickHouse/pull/15642) ([Azat Khuzhin](https://github.com/azat)).
+* Add a setting `output_format_pretty_row_numbers` to numerate the result in Pretty formats. This closes [#15350](https://github.com/ClickHouse/ClickHouse/issues/15350). [#15443](https://github.com/ClickHouse/ClickHouse/pull/15443) ([flynn](https://github.com/ucasFL)).
+* Added query obfuscation tool. It allows to share more queries for better testing. This closes [#15268](https://github.com/ClickHouse/ClickHouse/issues/15268). [#15321](https://github.com/ClickHouse/ClickHouse/pull/15321) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add table function `null('structure')`. [#14797](https://github.com/ClickHouse/ClickHouse/pull/14797) ([vxider](https://github.com/Vxider)).
+* Added `formatReadableQuantity` function. It is useful for reading big numbers by human. [#14725](https://github.com/ClickHouse/ClickHouse/pull/14725) ([Artem Hnilov](https://github.com/BooBSD)).
+* Add format `LineAsString` that accepts a sequence of lines separated by newlines, every line is parsed as a whole as a single String field. [#14703](https://github.com/ClickHouse/ClickHouse/pull/14703) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)), [#13846](https://github.com/ClickHouse/ClickHouse/pull/13846) ([hexiaoting](https://github.com/hexiaoting)).
+* Add `JSONStrings` format which output data in arrays of strings. [#14333](https://github.com/ClickHouse/ClickHouse/pull/14333) ([hcz](https://github.com/hczhcz)).
+* Add support for "Raw" column format for `Regexp` format. It allows to simply extract subpatterns as a whole without any escaping rules. [#15363](https://github.com/ClickHouse/ClickHouse/pull/15363) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow configurable `NULL` representation for `TSV` output format. It is controlled by the setting `output_format_tsv_null_representation` which is `\N` by default. This closes [#9375](https://github.com/ClickHouse/ClickHouse/issues/9375). Note that the setting only controls output format and `\N` is the only supported `NULL` representation for `TSV` input format. [#14586](https://github.com/ClickHouse/ClickHouse/pull/14586) ([Kruglov Pavel](https://github.com/Avogar)).
+* Support Decimal data type for `MaterializeMySQL`. `MaterializeMySQL` is an experimental feature. [#14535](https://github.com/ClickHouse/ClickHouse/pull/14535) ([Winter Zhang](https://github.com/zhang2014)).
+* Add new feature: `SHOW DATABASES LIKE 'xxx'`. [#14521](https://github.com/ClickHouse/ClickHouse/pull/14521) ([hexiaoting](https://github.com/hexiaoting)).
+* Added a script to import (arbitrary) git repository to ClickHouse as a sample dataset. [#14471](https://github.com/ClickHouse/ClickHouse/pull/14471) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now insert statements can have asterisk (or variants) with column transformers in the column list. [#14453](https://github.com/ClickHouse/ClickHouse/pull/14453) ([Amos Bird](https://github.com/amosbird)).
+* New query complexity limit settings `max_rows_to_read_leaf`, `max_bytes_to_read_leaf` for distributed queries to limit max rows/bytes read on the leaf nodes. Limit is applied for local reads only, *excluding* the final merge stage on the root node. [#14221](https://github.com/ClickHouse/ClickHouse/pull/14221) ([Roman Khavronenko](https://github.com/hagen1778)).
+* Allow user to specify settings for `ReplicatedMergeTree*` storage in `<replicated_merge_tree>` section of config file. It works similarly to `<merge_tree>` section. For `ReplicatedMergeTree*` storages settings from `<merge_tree>` and `<replicated_merge_tree>` are applied together, but settings from `<replicated_merge_tree>` has higher priority. Added `system.replicated_merge_tree_settings` table. [#13573](https://github.com/ClickHouse/ClickHouse/pull/13573) ([Amos Bird](https://github.com/amosbird)).
+* Add `mapPopulateSeries` function. [#13166](https://github.com/ClickHouse/ClickHouse/pull/13166) ([Ildus Kurbangaliev](https://github.com/ildus)).
+* Supporting MySQL types: `decimal` (as ClickHouse `Decimal`) and `datetime` with sub-second precision (as `DateTime64`). [#11512](https://github.com/ClickHouse/ClickHouse/pull/11512) ([Vasily Nemkov](https://github.com/Enmk)).
+* Introduce `event_time_microseconds` field to `system.text_log`, `system.trace_log`, `system.query_log` and `system.query_thread_log` tables. [#14760](https://github.com/ClickHouse/ClickHouse/pull/14760) ([Bharat Nallan](https://github.com/bharatnc)).
+* Add `event_time_microseconds` to `system.asynchronous_metric_log` & `system.metric_log` tables. [#14514](https://github.com/ClickHouse/ClickHouse/pull/14514) ([Bharat Nallan](https://github.com/bharatnc)).
+* Add `query_start_time_microseconds` field to `system.query_log` & `system.query_thread_log` tables. [#14252](https://github.com/ClickHouse/ClickHouse/pull/14252) ([Bharat Nallan](https://github.com/bharatnc)).
+
+#### Bug Fix
+
+* Fix the case when memory can be overallocated regardless to the limit. This closes [#14560](https://github.com/ClickHouse/ClickHouse/issues/14560). [#16206](https://github.com/ClickHouse/ClickHouse/pull/16206) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `executable` dictionary source hang. In previous versions, when using some formats (e.g. `JSONEachRow`) data was not feed to a child process before it outputs at least something. This closes [#1697](https://github.com/ClickHouse/ClickHouse/issues/1697). This closes [#2455](https://github.com/ClickHouse/ClickHouse/issues/2455). [#14525](https://github.com/ClickHouse/ClickHouse/pull/14525) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix double free in case of exception in function `dictGet`. It could have happened if dictionary was loaded with error. [#16429](https://github.com/ClickHouse/ClickHouse/pull/16429) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix group by with totals/rollup/cube modifers and min/max functions over group by keys. Fixes [#16393](https://github.com/ClickHouse/ClickHouse/issues/16393). [#16397](https://github.com/ClickHouse/ClickHouse/pull/16397) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix async Distributed INSERT with prefer_localhost_replica=0 and internal_replication. [#16358](https://github.com/ClickHouse/ClickHouse/pull/16358) ([Azat Khuzhin](https://github.com/azat)).
+* Fix a very wrong code in TwoLevelStringHashTable implementation, which might lead to memory leak. [#16264](https://github.com/ClickHouse/ClickHouse/pull/16264) ([Amos Bird](https://github.com/amosbird)).
+* Fix segfault in some cases of wrong aggregation in lambdas. [#16082](https://github.com/ClickHouse/ClickHouse/pull/16082) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix `ALTER MODIFY ... ORDER BY` query hang for `ReplicatedVersionedCollapsingMergeTree`. This fixes [#15980](https://github.com/ClickHouse/ClickHouse/issues/15980). [#16011](https://github.com/ClickHouse/ClickHouse/pull/16011) ([alesapin](https://github.com/alesapin)).
+* `MaterializeMySQL` (experimental feature): Fix collate name & charset name parser and support `length = 0` for string type. [#16008](https://github.com/ClickHouse/ClickHouse/pull/16008) ([Winter Zhang](https://github.com/zhang2014)).
+* Allow to use `direct` layout for dictionaries with complex keys. [#16007](https://github.com/ClickHouse/ClickHouse/pull/16007) ([Anton Popov](https://github.com/CurtizJ)).
+* Prevent replica hang for 5-10 mins when replication error happens after a period of inactivity. [#15987](https://github.com/ClickHouse/ClickHouse/pull/15987) ([filimonov](https://github.com/filimonov)).
+* Fix rare segfaults when inserting into or selecting from MaterializedView and concurrently dropping target table (for Atomic database engine). [#15984](https://github.com/ClickHouse/ClickHouse/pull/15984) ([tavplubix](https://github.com/tavplubix)).
+* Fix ambiguity in parsing of settings profiles: `CREATE USER ... SETTINGS profile readonly` is now considered as using a profile named `readonly`, not a setting named `profile` with the readonly constraint. This fixes [#15628](https://github.com/ClickHouse/ClickHouse/issues/15628). [#15982](https://github.com/ClickHouse/ClickHouse/pull/15982) ([Vitaly Baranov](https://github.com/vitlibar)).
+* `MaterializeMySQL` (experimental feature): Fix crash on create database failure. [#15954](https://github.com/ClickHouse/ClickHouse/pull/15954) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed `DROP TABLE IF EXISTS` failure with `Table ... does not exist` error when table is concurrently renamed (for Atomic database engine). Fixed rare deadlock when concurrently executing some DDL queries with multiple tables (like `DROP DATABASE` and `RENAME TABLE`) - Fixed `DROP/DETACH DATABASE` failure with `Table ... does not exist` when concurrently executing `DROP/DETACH TABLE`. [#15934](https://github.com/ClickHouse/ClickHouse/pull/15934) ([tavplubix](https://github.com/tavplubix)).
+* Fix incorrect empty result for query from `Distributed` table if query has `WHERE`, `PREWHERE` and `GLOBAL IN`. Fixes [#15792](https://github.com/ClickHouse/ClickHouse/issues/15792). [#15933](https://github.com/ClickHouse/ClickHouse/pull/15933) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixes [#12513](https://github.com/ClickHouse/ClickHouse/issues/12513): difference expressions with same alias when query is reanalyzed. [#15886](https://github.com/ClickHouse/ClickHouse/pull/15886) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix possible very rare deadlocks in RBAC implementation. [#15875](https://github.com/ClickHouse/ClickHouse/pull/15875) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix exception `Block structure mismatch` in `SELECT ... ORDER BY DESC` queries which were executed after `ALTER MODIFY COLUMN` query. Fixes [#15800](https://github.com/ClickHouse/ClickHouse/issues/15800). [#15852](https://github.com/ClickHouse/ClickHouse/pull/15852) ([alesapin](https://github.com/alesapin)).
+* `MaterializeMySQL` (experimental feature): Fix `select count()` inaccuracy. [#15767](https://github.com/ClickHouse/ClickHouse/pull/15767) ([tavplubix](https://github.com/tavplubix)).
+* Fix some cases of queries, in which only virtual columns are selected. Previously `Not found column _nothing in block` exception may be thrown. Fixes [#12298](https://github.com/ClickHouse/ClickHouse/issues/12298). [#15756](https://github.com/ClickHouse/ClickHouse/pull/15756) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix drop of materialized view with inner table in Atomic database (hangs all subsequent DROP TABLE due to hang of the worker thread, due to recursive DROP TABLE for inner table of MV). [#15743](https://github.com/ClickHouse/ClickHouse/pull/15743) ([Azat Khuzhin](https://github.com/azat)).
+* Possibility to move part to another disk/volume if the first attempt was failed. [#15723](https://github.com/ClickHouse/ClickHouse/pull/15723) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fix error `Cannot find column` which may happen at insertion into `MATERIALIZED VIEW` in case if query for `MV` containes `ARRAY JOIN`. [#15717](https://github.com/ClickHouse/ClickHouse/pull/15717) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed too low default value of `max_replicated_logs_to_keep` setting, which might cause replicas to become lost too often. Improve lost replica recovery process by choosing the most up-to-date replica to clone. Also do not remove old parts from lost replica, detach them instead. [#15701](https://github.com/ClickHouse/ClickHouse/pull/15701) ([tavplubix](https://github.com/tavplubix)).
+* Fix rare race condition in dictionaries and tables from MySQL. [#15686](https://github.com/ClickHouse/ClickHouse/pull/15686) ([alesapin](https://github.com/alesapin)).
+* Fix (benign) race condition in AMQP-CPP. [#15667](https://github.com/ClickHouse/ClickHouse/pull/15667) ([alesapin](https://github.com/alesapin)).
+* Fix error `Cannot add simple transform to empty Pipe` which happened while reading from `Buffer` table which has different structure than destination table. It was possible if destination table returned empty result for query. Fixes [#15529](https://github.com/ClickHouse/ClickHouse/issues/15529). [#15662](https://github.com/ClickHouse/ClickHouse/pull/15662) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Proper error handling during insert into MergeTree with S3. MergeTree over S3 is an experimental feature. [#15657](https://github.com/ClickHouse/ClickHouse/pull/15657) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fixed bug with S3 table function: region from URL was not applied to S3 client configuration. [#15646](https://github.com/ClickHouse/ClickHouse/pull/15646) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fix the order of destruction for resources in `ReadFromStorage` step of query plan. It might cause crashes in rare cases. Possibly connected with [#15610](https://github.com/ClickHouse/ClickHouse/issues/15610). [#15645](https://github.com/ClickHouse/ClickHouse/pull/15645) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Subtract `ReadonlyReplica` metric when detach readonly tables. [#15592](https://github.com/ClickHouse/ClickHouse/pull/15592) ([sundyli](https://github.com/sundy-li)).
+* Fixed `Element ... is not a constant expression` error when using `JSON*` function result in `VALUES`, `LIMIT` or right side of `IN` operator. [#15589](https://github.com/ClickHouse/ClickHouse/pull/15589) ([tavplubix](https://github.com/tavplubix)).
+* Query will finish faster in case of exception. Cancel execution on remote replicas if exception happens. [#15578](https://github.com/ClickHouse/ClickHouse/pull/15578) ([Azat Khuzhin](https://github.com/azat)).
+* Prevent the possibility of error message `Could not calculate available disk space (statvfs), errno: 4, strerror: Interrupted system call`. This fixes [#15541](https://github.com/ClickHouse/ClickHouse/issues/15541). [#15557](https://github.com/ClickHouse/ClickHouse/pull/15557) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `Database <db> does not exist.` in queries with IN and Distributed table when there's no database on initiator. [#15538](https://github.com/ClickHouse/ClickHouse/pull/15538) ([Artem Zuikov](https://github.com/4ertus2)).
+* Mutation might hang waiting for some non-existent part after `MOVE` or `REPLACE PARTITION` or, in rare cases, after `DETACH` or `DROP PARTITION`. It's fixed. [#15537](https://github.com/ClickHouse/ClickHouse/pull/15537) ([tavplubix](https://github.com/tavplubix)).
+* Fix bug when `ILIKE` operator stops being case insensitive if `LIKE` with the same pattern was executed. [#15536](https://github.com/ClickHouse/ClickHouse/pull/15536) ([alesapin](https://github.com/alesapin)).
+* Fix `Missing columns` errors when selecting columns which absent in data, but depend on other columns which also absent in data. Fixes [#15530](https://github.com/ClickHouse/ClickHouse/issues/15530). [#15532](https://github.com/ClickHouse/ClickHouse/pull/15532) ([alesapin](https://github.com/alesapin)).
+* Throw an error when a single parameter is passed to ReplicatedMergeTree instead of ignoring it. [#15516](https://github.com/ClickHouse/ClickHouse/pull/15516) ([nvartolomei](https://github.com/nvartolomei)).
+* Fix bug with event subscription in DDLWorker which rarely may lead to query hangs in `ON CLUSTER`. Introduced in [#13450](https://github.com/ClickHouse/ClickHouse/issues/13450). [#15477](https://github.com/ClickHouse/ClickHouse/pull/15477) ([alesapin](https://github.com/alesapin)).
+* Report proper error when the second argument of `boundingRatio` aggregate function has a wrong type. [#15407](https://github.com/ClickHouse/ClickHouse/pull/15407) ([detailyang](https://github.com/detailyang)).
+* Fixes [#15365](https://github.com/ClickHouse/ClickHouse/issues/15365): attach a database with MySQL engine throws exception (no query context). [#15384](https://github.com/ClickHouse/ClickHouse/pull/15384) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix the case of multiple occurrences of column transformers in a select query. [#15378](https://github.com/ClickHouse/ClickHouse/pull/15378) ([Amos Bird](https://github.com/amosbird)).
+* Fixed compression in `S3` storage. [#15376](https://github.com/ClickHouse/ClickHouse/pull/15376) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fix bug where queries like `SELECT toStartOfDay(today())` fail complaining about empty time_zone argument. [#15319](https://github.com/ClickHouse/ClickHouse/pull/15319) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix race condition during MergeTree table rename and background cleanup. [#15304](https://github.com/ClickHouse/ClickHouse/pull/15304) ([alesapin](https://github.com/alesapin)).
+* Fix rare race condition on server startup when system logs are enabled. [#15300](https://github.com/ClickHouse/ClickHouse/pull/15300) ([alesapin](https://github.com/alesapin)).
+* Fix hang of queries with a lot of subqueries to same table of `MySQL` engine. Previously, if there were more than 16 subqueries to same `MySQL` table in query, it hang forever. [#15299](https://github.com/ClickHouse/ClickHouse/pull/15299) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix MSan report in QueryLog. Uninitialized memory can be used for the field `memory_usage`. [#15258](https://github.com/ClickHouse/ClickHouse/pull/15258) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix 'Unknown identifier' in GROUP BY when query has JOIN over Merge table. [#15242](https://github.com/ClickHouse/ClickHouse/pull/15242) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix instance crash when using `joinGet` with `LowCardinality` types. This fixes [#15214](https://github.com/ClickHouse/ClickHouse/issues/15214). [#15220](https://github.com/ClickHouse/ClickHouse/pull/15220) ([Amos Bird](https://github.com/amosbird)).
+* Fix bug in table engine `Buffer` which does not allow to insert data of new structure into `Buffer` after `ALTER` query. Fixes [#15117](https://github.com/ClickHouse/ClickHouse/issues/15117). [#15192](https://github.com/ClickHouse/ClickHouse/pull/15192) ([alesapin](https://github.com/alesapin)).
+* Adjust Decimal field size in MySQL column definition packet. [#15152](https://github.com/ClickHouse/ClickHouse/pull/15152) ([maqroll](https://github.com/maqroll)).
+* Fixes `Data compressed with different methods` in `join_algorithm='auto'`. Keep LowCardinality as type for left table join key in `join_algorithm='partial_merge'`. [#15088](https://github.com/ClickHouse/ClickHouse/pull/15088) ([Artem Zuikov](https://github.com/4ertus2)).
+* Update `jemalloc` to fix `percpu_arena` with affinity mask. [#15035](https://github.com/ClickHouse/ClickHouse/pull/15035) ([Azat Khuzhin](https://github.com/azat)). [#14957](https://github.com/ClickHouse/ClickHouse/pull/14957) ([Azat Khuzhin](https://github.com/azat)).
+* We already use padded comparison between String and FixedString (https://github.com/ClickHouse/ClickHouse/blob/master/src/Functions/FunctionsComparison.h#L333). This PR applies the same logic to field comparison which corrects the usage of FixedString as primary keys. This fixes [#14908](https://github.com/ClickHouse/ClickHouse/issues/14908). [#15033](https://github.com/ClickHouse/ClickHouse/pull/15033) ([Amos Bird](https://github.com/amosbird)).
+* If function `bar` was called with specifically crafted arguments, buffer overflow was possible. This closes [#13926](https://github.com/ClickHouse/ClickHouse/issues/13926). [#15028](https://github.com/ClickHouse/ClickHouse/pull/15028) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `Cannot rename ... errno: 22, strerror: Invalid argument` error on DDL query execution in Atomic database when running clickhouse-server in Docker on Mac OS. [#15024](https://github.com/ClickHouse/ClickHouse/pull/15024) ([tavplubix](https://github.com/tavplubix)).
+* Fix crash in RIGHT or FULL JOIN with join_algorith='auto' when memory limit exceeded and we should change HashJoin with MergeJoin. [#15002](https://github.com/ClickHouse/ClickHouse/pull/15002) ([Artem Zuikov](https://github.com/4ertus2)).
+* Now settings `number_of_free_entries_in_pool_to_execute_mutation` and `number_of_free_entries_in_pool_to_lower_max_size_of_merge` can be equal to `background_pool_size`. [#14975](https://github.com/ClickHouse/ClickHouse/pull/14975) ([alesapin](https://github.com/alesapin)).
+* Fix to make predicate push down work when subquery contains `finalizeAggregation` function. Fixes [#14847](https://github.com/ClickHouse/ClickHouse/issues/14847). [#14937](https://github.com/ClickHouse/ClickHouse/pull/14937) ([filimonov](https://github.com/filimonov)).
+* Publish CPU frequencies per logical core in `system.asynchronous_metrics`. This fixes [#14923](https://github.com/ClickHouse/ClickHouse/issues/14923). [#14924](https://github.com/ClickHouse/ClickHouse/pull/14924) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* `MaterializeMySQL` (experimental feature): Fixed `.metadata.tmp File exists` error. [#14898](https://github.com/ClickHouse/ClickHouse/pull/14898) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix the issue when some invocations of `extractAllGroups` function may trigger "Memory limit exceeded" error. This fixes [#13383](https://github.com/ClickHouse/ClickHouse/issues/13383). [#14889](https://github.com/ClickHouse/ClickHouse/pull/14889) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix SIGSEGV for an attempt to INSERT into StorageFile with file descriptor. [#14887](https://github.com/ClickHouse/ClickHouse/pull/14887) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed segfault in `cache` dictionary [#14837](https://github.com/ClickHouse/ClickHouse/issues/14837). [#14879](https://github.com/ClickHouse/ClickHouse/pull/14879) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* `MaterializeMySQL` (experimental feature): Fixed bug in parsing MySQL binlog events, which causes `Attempt to read after eof` and `Packet payload is not fully read` in `MaterializeMySQL` database engine. [#14852](https://github.com/ClickHouse/ClickHouse/pull/14852) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix rare error in `SELECT` queries when the queried column has `DEFAULT` expression which depends on the other column which also has `DEFAULT` and not present in select query and not exists on disk. Partially fixes [#14531](https://github.com/ClickHouse/ClickHouse/issues/14531). [#14845](https://github.com/ClickHouse/ClickHouse/pull/14845) ([alesapin](https://github.com/alesapin)).
+* Fix a problem where the server may get stuck on startup while talking to ZooKeeper, if the configuration files have to be fetched from ZK (using the `from_zk` include option). This fixes [#14814](https://github.com/ClickHouse/ClickHouse/issues/14814). [#14843](https://github.com/ClickHouse/ClickHouse/pull/14843) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fix wrong monotonicity detection for shrunk `Int -> Int` cast of signed types. It might lead to incorrect query result. This bug is unveiled in [#14513](https://github.com/ClickHouse/ClickHouse/issues/14513). [#14783](https://github.com/ClickHouse/ClickHouse/pull/14783) ([Amos Bird](https://github.com/amosbird)).
+* `Replace` column transformer should replace identifiers with cloned ASTs. This fixes [#14695](https://github.com/ClickHouse/ClickHouse/issues/14695) . [#14734](https://github.com/ClickHouse/ClickHouse/pull/14734) ([Amos Bird](https://github.com/amosbird)).
+* Fixed missed default database name in metadata of materialized view when executing `ALTER ... MODIFY QUERY`. [#14664](https://github.com/ClickHouse/ClickHouse/pull/14664) ([tavplubix](https://github.com/tavplubix)).
+* Fix bug when `ALTER UPDATE` mutation with `Nullable` column in assignment expression and constant value (like `UPDATE x = 42`) leads to incorrect value in column or segfault. Fixes [#13634](https://github.com/ClickHouse/ClickHouse/issues/13634), [#14045](https://github.com/ClickHouse/ClickHouse/issues/14045). [#14646](https://github.com/ClickHouse/ClickHouse/pull/14646) ([alesapin](https://github.com/alesapin)).
+* Fix wrong Decimal multiplication result caused wrong decimal scale of result column. [#14603](https://github.com/ClickHouse/ClickHouse/pull/14603) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix function `has` with `LowCardinality` of `Nullable`. [#14591](https://github.com/ClickHouse/ClickHouse/pull/14591) ([Mike](https://github.com/myrrc)).
+* Cleanup data directory after Zookeeper exceptions during CreateQuery for StorageReplicatedMergeTree Engine. [#14563](https://github.com/ClickHouse/ClickHouse/pull/14563) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix rare segfaults in functions with combinator `-Resample`, which could appear in result of overflow with very large parameters. [#14562](https://github.com/ClickHouse/ClickHouse/pull/14562) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix a bug when converting `Nullable(String)` to Enum. Introduced by [#12745](https://github.com/ClickHouse/ClickHouse/pull/12745). This fixes [#14435](https://github.com/ClickHouse/ClickHouse/issues/14435). [#14530](https://github.com/ClickHouse/ClickHouse/pull/14530) ([Amos Bird](https://github.com/amosbird)).
+* Fixed the incorrect sorting order of `Nullable` column. This fixes [#14344](https://github.com/ClickHouse/ClickHouse/issues/14344). [#14495](https://github.com/ClickHouse/ClickHouse/pull/14495) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix `currentDatabase()` function cannot be used in `ON CLUSTER` ddl query. [#14211](https://github.com/ClickHouse/ClickHouse/pull/14211) ([Winter Zhang](https://github.com/zhang2014)).
+* `MaterializeMySQL` (experimental feature): Fixed `Packet payload is not fully read` error in `MaterializeMySQL` database engine. [#14696](https://github.com/ClickHouse/ClickHouse/pull/14696) ([BohuTANG](https://github.com/BohuTANG)).
+
+#### Improvement
+
+* Enable `Atomic` database engine by default for newly created databases. [#15003](https://github.com/ClickHouse/ClickHouse/pull/15003) ([tavplubix](https://github.com/tavplubix)).
+* Add the ability to specify specialized codecs like `Delta`, `T64`, etc. for columns with subtypes. Implements [#12551](https://github.com/ClickHouse/ClickHouse/issues/12551), fixes [#11397](https://github.com/ClickHouse/ClickHouse/issues/11397), fixes [#4609](https://github.com/ClickHouse/ClickHouse/issues/4609). [#15089](https://github.com/ClickHouse/ClickHouse/pull/15089) ([alesapin](https://github.com/alesapin)).
+* Dynamic reload of zookeeper config. [#14678](https://github.com/ClickHouse/ClickHouse/pull/14678) ([sundyli](https://github.com/sundy-li)).
+* Now it's allowed to execute `ALTER ... ON CLUSTER` queries regardless of the `<internal_replication>` setting in cluster config. [#16075](https://github.com/ClickHouse/ClickHouse/pull/16075) ([alesapin](https://github.com/alesapin)).
+* Now `joinGet` supports multi-key lookup. Continuation of [#12418](https://github.com/ClickHouse/ClickHouse/issues/12418). [#13015](https://github.com/ClickHouse/ClickHouse/pull/13015) ([Amos Bird](https://github.com/amosbird)).
+* Wait for `DROP/DETACH TABLE` to actually finish if `NO DELAY` or `SYNC` is specified for `Atomic` database. [#15448](https://github.com/ClickHouse/ClickHouse/pull/15448) ([tavplubix](https://github.com/tavplubix)).
+* Now it's possible to change the type of version column for `VersionedCollapsingMergeTree` with `ALTER` query. [#15442](https://github.com/ClickHouse/ClickHouse/pull/15442) ([alesapin](https://github.com/alesapin)).
+* Unfold `{database}`, `{table}` and `{uuid}` macros in `zookeeper_path` on replicated table creation. Do not allow `RENAME TABLE` if it may break `zookeeper_path` after server restart. Fixes [#6917](https://github.com/ClickHouse/ClickHouse/issues/6917). [#15348](https://github.com/ClickHouse/ClickHouse/pull/15348) ([tavplubix](https://github.com/tavplubix)).
+* The function `now` allows an argument with timezone. This closes [15264](https://github.com/ClickHouse/ClickHouse/issues/15264). [#15285](https://github.com/ClickHouse/ClickHouse/pull/15285) ([flynn](https://github.com/ucasFL)).
+* Do not allow connections to ClickHouse server until all scripts in `/docker-entrypoint-initdb.d/` are executed. [#15244](https://github.com/ClickHouse/ClickHouse/pull/15244) ([Aleksei Kozharin](https://github.com/alekseik1)).
+* Added `optimize` setting to `EXPLAIN PLAN` query. If enabled, query plan level optimisations are applied. Enabled by default. [#15201](https://github.com/ClickHouse/ClickHouse/pull/15201) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Proper exception message for wrong number of arguments of CAST. This closes [#13992](https://github.com/ClickHouse/ClickHouse/issues/13992). [#15029](https://github.com/ClickHouse/ClickHouse/pull/15029) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add option to disable TTL move on data part insert. [#15000](https://github.com/ClickHouse/ClickHouse/pull/15000) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Ignore key constraints when doing mutations. Without this pull request, it's not possible to do mutations when `force_index_by_date = 1` or `force_primary_key = 1`. [#14973](https://github.com/ClickHouse/ClickHouse/pull/14973) ([Amos Bird](https://github.com/amosbird)).
+* Allow to drop Replicated table if previous drop attempt was failed due to ZooKeeper session expiration. This fixes [#11891](https://github.com/ClickHouse/ClickHouse/issues/11891). [#14926](https://github.com/ClickHouse/ClickHouse/pull/14926) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed excessive settings constraint violation when running SELECT with SETTINGS from a distributed table. [#14876](https://github.com/ClickHouse/ClickHouse/pull/14876) ([Amos Bird](https://github.com/amosbird)).
+* Provide a `load_balancing_first_offset` query setting to explicitly state what the first replica is. It's used together with `FIRST_OR_RANDOM` load balancing strategy, which allows to control replicas workload. [#14867](https://github.com/ClickHouse/ClickHouse/pull/14867) ([Amos Bird](https://github.com/amosbird)).
+* Show subqueries for `SET` and `JOIN` in `EXPLAIN` result. [#14856](https://github.com/ClickHouse/ClickHouse/pull/14856) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Allow using multi-volume storage configuration in storage `Distributed`. [#14839](https://github.com/ClickHouse/ClickHouse/pull/14839) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Construct `query_start_time` and `query_start_time_microseconds` from the same timespec. [#14831](https://github.com/ClickHouse/ClickHouse/pull/14831) ([Bharat Nallan](https://github.com/bharatnc)).
+* Support for disabling persistency for `StorageJoin` and `StorageSet`, this feature is controlled by setting `disable_set_and_join_persistency`. And this PR solved issue [#6318](https://github.com/ClickHouse/ClickHouse/issues/6318). [#14776](https://github.com/ClickHouse/ClickHouse/pull/14776) ([vxider](https://github.com/Vxider)).
+* Now `COLUMNS` can be used to wrap over a list of columns and apply column transformers afterwards. [#14775](https://github.com/ClickHouse/ClickHouse/pull/14775) ([Amos Bird](https://github.com/amosbird)).
+* Add `merge_algorithm` to `system.merges` table to improve merging inspections. [#14705](https://github.com/ClickHouse/ClickHouse/pull/14705) ([Amos Bird](https://github.com/amosbird)).
+* Fix potential memory leak caused by zookeeper exists watch. [#14693](https://github.com/ClickHouse/ClickHouse/pull/14693) ([hustnn](https://github.com/hustnn)).
+* Allow parallel execution of distributed DDL. [#14684](https://github.com/ClickHouse/ClickHouse/pull/14684) ([Azat Khuzhin](https://github.com/azat)).
+* Add `QueryMemoryLimitExceeded` event counter. This closes [#14589](https://github.com/ClickHouse/ClickHouse/issues/14589). [#14647](https://github.com/ClickHouse/ClickHouse/pull/14647) ([fastio](https://github.com/fastio)).
+* Fix some trailing whitespaces in query formatting. [#14595](https://github.com/ClickHouse/ClickHouse/pull/14595) ([Azat Khuzhin](https://github.com/azat)).
+* ClickHouse treats partition expr and key expr differently. Partition expr is used to construct an minmax index containing related columns, while primary key expr is stored as an expr. Sometimes user might partition a table at coarser levels, such as `partition by i / 1000`. However, binary operators are not monotonic and this PR tries to fix that. It might also benifit other use cases. [#14513](https://github.com/ClickHouse/ClickHouse/pull/14513) ([Amos Bird](https://github.com/amosbird)).
+* Add an option to skip access checks for `DiskS3`. `s3` disk is an experimental feature. [#14497](https://github.com/ClickHouse/ClickHouse/pull/14497) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Speed up server shutdown process if there are ongoing S3 requests. [#14496](https://github.com/ClickHouse/ClickHouse/pull/14496) ([Pavel Kovalenko](https://github.com/Jokser)).
+* `SYSTEM RELOAD CONFIG` now throws an exception if failed to reload and continues using the previous users.xml. The background periodic reloading also continues using the previous users.xml if failed to reload. [#14492](https://github.com/ClickHouse/ClickHouse/pull/14492) ([Vitaly Baranov](https://github.com/vitlibar)).
+* For INSERTs with inline data in VALUES format in the script mode of `clickhouse-client`, support semicolon as the data terminator, in addition to the new line. Closes [#12288](https://github.com/ClickHouse/ClickHouse/issues/12288). [#13192](https://github.com/ClickHouse/ClickHouse/pull/13192) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Support custom codecs in compact parts. [#12183](https://github.com/ClickHouse/ClickHouse/pull/12183) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Performance Improvement
+
+* Enable compact parts by default for small parts. This will allow to process frequent inserts slightly more efficiently (4..100 times). [#11913](https://github.com/ClickHouse/ClickHouse/pull/11913) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve `quantileTDigest` performance. This fixes [#2668](https://github.com/ClickHouse/ClickHouse/issues/2668). [#15542](https://github.com/ClickHouse/ClickHouse/pull/15542) ([Kruglov Pavel](https://github.com/Avogar)).
+* Significantly reduce memory usage in AggregatingInOrderTransform/optimize_aggregation_in_order. [#15543](https://github.com/ClickHouse/ClickHouse/pull/15543) ([Azat Khuzhin](https://github.com/azat)).
+* Faster 256-bit multiplication. [#15418](https://github.com/ClickHouse/ClickHouse/pull/15418) ([Artem Zuikov](https://github.com/4ertus2)).
+* Improve performance of 256-bit types using (u)int64_t as base type for wide integers. Original wide integers use 8-bit types as base. [#14859](https://github.com/ClickHouse/ClickHouse/pull/14859) ([Artem Zuikov](https://github.com/4ertus2)).
+* Explicitly use a temporary disk to store vertical merge temporary data. [#15639](https://github.com/ClickHouse/ClickHouse/pull/15639) ([Grigory Pervakov](https://github.com/GrigoryPervakov)).
+* Use one S3 DeleteObjects request instead of multiple DeleteObject in a loop. No any functionality changes, so covered by existing tests like integration/test_log_family_s3. [#15238](https://github.com/ClickHouse/ClickHouse/pull/15238) ([ianton-ru](https://github.com/ianton-ru)).
+* Fix `DateTime <op> DateTime` mistakenly choosing the slow generic implementation. This fixes [#15153](https://github.com/ClickHouse/ClickHouse/issues/15153). [#15178](https://github.com/ClickHouse/ClickHouse/pull/15178) ([Amos Bird](https://github.com/amosbird)).
+* Improve performance of GROUP BY key of type `FixedString`. [#15034](https://github.com/ClickHouse/ClickHouse/pull/15034) ([Amos Bird](https://github.com/amosbird)).
+* Only `mlock` code segment when starting clickhouse-server. In previous versions, all mapped regions were locked in memory, including debug info. Debug info is usually splitted to a separate file but if it isn't, it led to +2..3 GiB memory usage. [#14929](https://github.com/ClickHouse/ClickHouse/pull/14929) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* ClickHouse binary become smaller due to link time optimization.
+
+#### Build/Testing/Packaging Improvement
+
+* Now we use clang-11 for production ClickHouse build. [#15239](https://github.com/ClickHouse/ClickHouse/pull/15239) ([alesapin](https://github.com/alesapin)).
+* Now we use clang-11 to build ClickHouse in CI. [#14846](https://github.com/ClickHouse/ClickHouse/pull/14846) ([alesapin](https://github.com/alesapin)).
+* Switch binary builds (Linux, Darwin, AArch64, FreeDSD) to clang-11. [#15622](https://github.com/ClickHouse/ClickHouse/pull/15622) ([Ilya Yatsishin](https://github.com/qoega)).
+* Now all test images use `llvm-symbolizer-11`. [#15069](https://github.com/ClickHouse/ClickHouse/pull/15069) ([alesapin](https://github.com/alesapin)).
+* Allow to build with llvm-11. [#15366](https://github.com/ClickHouse/ClickHouse/pull/15366) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Switch from `clang-tidy-10` to `clang-tidy-11`. [#14922](https://github.com/ClickHouse/ClickHouse/pull/14922) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Use LLVM's experimental pass manager by default. [#15608](https://github.com/ClickHouse/ClickHouse/pull/15608) ([Danila Kutenin](https://github.com/danlark1)).
+* Don't allow any C++ translation unit to build more than 10 minutes or to use more than 10 GB or memory. This fixes [#14925](https://github.com/ClickHouse/ClickHouse/issues/14925). [#15060](https://github.com/ClickHouse/ClickHouse/pull/15060) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make performance test more stable and representative by splitting test runs and profile runs. [#15027](https://github.com/ClickHouse/ClickHouse/pull/15027) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Attempt to make performance test more reliable. It is done by remapping the executable memory of the process on the fly with `madvise` to use transparent huge pages - it can lower the number of iTLB misses which is the main source of instabilities in performance tests. [#14685](https://github.com/ClickHouse/ClickHouse/pull/14685) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Convert to python3. This closes [#14886](https://github.com/ClickHouse/ClickHouse/issues/14886). [#15007](https://github.com/ClickHouse/ClickHouse/pull/15007) ([Azat Khuzhin](https://github.com/azat)).
+* Fail early in functional tests if server failed to respond. This closes [#15262](https://github.com/ClickHouse/ClickHouse/issues/15262). [#15267](https://github.com/ClickHouse/ClickHouse/pull/15267) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow to run AArch64 version of clickhouse-server without configs. This facilitates [#15174](https://github.com/ClickHouse/ClickHouse/issues/15174). [#15266](https://github.com/ClickHouse/ClickHouse/pull/15266) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improvements in CI docker images: get rid of ZooKeeper and single script for test configs installation. [#15215](https://github.com/ClickHouse/ClickHouse/pull/15215) ([alesapin](https://github.com/alesapin)).
+* Fix CMake options forwarding in fast test script. Fixes error in [#14711](https://github.com/ClickHouse/ClickHouse/issues/14711). [#15155](https://github.com/ClickHouse/ClickHouse/pull/15155) ([alesapin](https://github.com/alesapin)).
+* Added a script to perform hardware benchmark in a single command. [#15115](https://github.com/ClickHouse/ClickHouse/pull/15115) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Splitted huge test `test_dictionaries_all_layouts_and_sources` into smaller ones. [#15110](https://github.com/ClickHouse/ClickHouse/pull/15110) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Maybe fix MSan report in base64 (on servers with AVX-512). This fixes [#14006](https://github.com/ClickHouse/ClickHouse/issues/14006). [#15030](https://github.com/ClickHouse/ClickHouse/pull/15030) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Reformat and cleanup code in all integration test *.py files. [#14864](https://github.com/ClickHouse/ClickHouse/pull/14864) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix MaterializeMySQL empty transaction unstable test case found in CI. [#14854](https://github.com/ClickHouse/ClickHouse/pull/14854) ([Winter Zhang](https://github.com/zhang2014)).
+* Attempt to speed up build a little. [#14808](https://github.com/ClickHouse/ClickHouse/pull/14808) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Speed up build a little by removing unused headers. [#14714](https://github.com/ClickHouse/ClickHouse/pull/14714) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix build failure in OSX. [#14761](https://github.com/ClickHouse/ClickHouse/pull/14761) ([Winter Zhang](https://github.com/zhang2014)).
+* Enable ccache by default in cmake if it's found in OS. [#14575](https://github.com/ClickHouse/ClickHouse/pull/14575) ([alesapin](https://github.com/alesapin)).
+* Control CI builds configuration from the ClickHouse repository. [#14547](https://github.com/ClickHouse/ClickHouse/pull/14547) ([alesapin](https://github.com/alesapin)).
+* In CMake files: - Moved some options' descriptions' parts to comments above. - Replace 0 -> `OFF`, 1 -> `ON` in `option`s default values. - Added some descriptions and links to docs to the options. - Replaced `FUZZER` option (there is another option `ENABLE_FUZZING` which also enables same functionality). - Removed `ENABLE_GTEST_LIBRARY` option as there is `ENABLE_TESTS`. See the full description in PR: [#14711](https://github.com/ClickHouse/ClickHouse/pull/14711) ([Mike](https://github.com/myrrc)).
+* Make binary a bit smaller (~50 Mb for debug version). [#14555](https://github.com/ClickHouse/ClickHouse/pull/14555) ([Artem Zuikov](https://github.com/4ertus2)).
+* Use std::filesystem::path in ConfigProcessor for concatenating file paths. [#14558](https://github.com/ClickHouse/ClickHouse/pull/14558) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix debug assertion in `bitShiftLeft()` when called with negative big integer. [#14697](https://github.com/ClickHouse/ClickHouse/pull/14697) ([Artem Zuikov](https://github.com/4ertus2)).
+
+
+## ClickHouse release 20.9
+
+### ClickHouse release v20.9.7.11-stable, 2020-12-07
+
+#### Performance Improvement
+
+* Fix performance of reading from `Merge` tables over huge number of `MergeTree` tables. Fixes [#7748](https://github.com/ClickHouse/ClickHouse/issues/7748). [#16988](https://github.com/ClickHouse/ClickHouse/pull/16988) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Bug Fix
+
+* Do not restore parts from WAL if `in_memory_parts_enable_wal` is disabled. [#17802](https://github.com/ClickHouse/ClickHouse/pull/17802) ([detailyang](https://github.com/detailyang)).
+* Fixed segfault when there is not enough space when inserting into `Distributed` table. [#17737](https://github.com/ClickHouse/ClickHouse/pull/17737) ([tavplubix](https://github.com/tavplubix)).
+* Fixed problem when ClickHouse fails to resume connection to MySQL servers. [#17681](https://github.com/ClickHouse/ClickHouse/pull/17681) ([Alexander Kazakov](https://github.com/Akazz)).
+* Fixed `Function not implemented` error when executing `RENAME` query in `Atomic` database with ClickHouse running on Windows Subsystem for Linux. Fixes [#17661](https://github.com/ClickHouse/ClickHouse/issues/17661). [#17664](https://github.com/ClickHouse/ClickHouse/pull/17664) ([tavplubix](https://github.com/tavplubix)).
+* When clickhouse-client is used in interactive mode with multiline queries, single line comment was erronously extended till the end of query. This fixes [#13654](https://github.com/ClickHouse/ClickHouse/issues/13654). [#17565](https://github.com/ClickHouse/ClickHouse/pull/17565) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix the issue when server can stop accepting connections in very rare cases. [#17542](https://github.com/ClickHouse/ClickHouse/pull/17542) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix alter query hang when the corresponding mutation was killed on the different replica. Fixes [#16953](https://github.com/ClickHouse/ClickHouse/issues/16953). [#17499](https://github.com/ClickHouse/ClickHouse/pull/17499) ([alesapin](https://github.com/alesapin)).
+* Fix bug when mark cache size was underestimated by clickhouse. It may happen when there are a lot of tiny files with marks. [#17496](https://github.com/ClickHouse/ClickHouse/pull/17496) ([alesapin](https://github.com/alesapin)).
+* Fix `ORDER BY` with enabled setting `optimize_redundant_functions_in_order_by`. [#17471](https://github.com/ClickHouse/ClickHouse/pull/17471) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix duplicates after `DISTINCT` which were possible because of incorrect optimization. Fixes [#17294](https://github.com/ClickHouse/ClickHouse/issues/17294). [#17296](https://github.com/ClickHouse/ClickHouse/pull/17296) ([li chengxiang](https://github.com/chengxianglibra)). [#17439](https://github.com/ClickHouse/ClickHouse/pull/17439) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix crash while reading from `JOIN` table with `LowCardinality` types. Fixes [#17228](https://github.com/ClickHouse/ClickHouse/issues/17228). [#17397](https://github.com/ClickHouse/ClickHouse/pull/17397) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix set index invalidation when there are const columns in the subquery. This fixes [#17246](https://github.com/ClickHouse/ClickHouse/issues/17246) . [#17249](https://github.com/ClickHouse/ClickHouse/pull/17249) ([Amos Bird](https://github.com/amosbird)).
+* Fix ColumnConst comparison which leads to crash. This fixed [#17088](https://github.com/ClickHouse/ClickHouse/issues/17088) . [#17135](https://github.com/ClickHouse/ClickHouse/pull/17135) ([Amos Bird](https://github.com/amosbird)).
+* Fixed crash on `CREATE TABLE ... AS some_table` query when `some_table` was created `AS table_function()` Fixes [#16944](https://github.com/ClickHouse/ClickHouse/issues/16944). [#17072](https://github.com/ClickHouse/ClickHouse/pull/17072) ([tavplubix](https://github.com/tavplubix)).
+* Bug fix for funciton fuzzBits, related issue: [#16980](https://github.com/ClickHouse/ClickHouse/issues/16980). [#17051](https://github.com/ClickHouse/ClickHouse/pull/17051) ([hexiaoting](https://github.com/hexiaoting)).
+* Avoid unnecessary network errors for remote queries which may be cancelled while execution, like queries with `LIMIT`. [#17006](https://github.com/ClickHouse/ClickHouse/pull/17006) ([Azat Khuzhin](https://github.com/azat)).
+* TODO. [#16866](https://github.com/ClickHouse/ClickHouse/pull/16866) ([tavplubix](https://github.com/tavplubix)).
+* Return number of affected rows for INSERT queries via MySQL protocol. Previously ClickHouse used to always return 0, it's fixed. Fixes [#16605](https://github.com/ClickHouse/ClickHouse/issues/16605). [#16715](https://github.com/ClickHouse/ClickHouse/pull/16715) ([Winter Zhang](https://github.com/zhang2014)).
+
+#### Build/Testing/Packaging Improvement
+
+* Update embedded timezone data to version 2020d (also update cctz to the latest master). [#17204](https://github.com/ClickHouse/ClickHouse/pull/17204) ([filimonov](https://github.com/filimonov)).
+
+
+### ClickHouse release v20.9.6.14-stable, 2020-11-20
+
+#### Improvement
+
+* Make it possible to connect to `clickhouse-server` secure endpoint which requires SNI. This is possible when `clickhouse-server` is hosted behind TLS proxy. [#16938](https://github.com/ClickHouse/ClickHouse/pull/16938) ([filimonov](https://github.com/filimonov)).
+* Conditional aggregate functions (for example: `avgIf`, `sumIf`, `maxIf`) should return `NULL` when miss rows and use nullable arguments. [#13964](https://github.com/ClickHouse/ClickHouse/pull/13964) ([Winter Zhang](https://github.com/zhang2014)).
+
+#### Bug Fix
+
+* Fix bug when `ON CLUSTER` queries may hang forever for non-leader ReplicatedMergeTreeTables. [#17089](https://github.com/ClickHouse/ClickHouse/pull/17089) ([alesapin](https://github.com/alesapin)).
+* Reresolve the IP of the `format_avro_schema_registry_url` in case of errors. [#16985](https://github.com/ClickHouse/ClickHouse/pull/16985) ([filimonov](https://github.com/filimonov)).
+* Fix possible server crash after `ALTER TABLE ... MODIFY COLUMN ... NewType` when `SELECT` have `WHERE` expression on altering column and alter does not finished yet. [#16968](https://github.com/ClickHouse/ClickHouse/pull/16968) ([Amos Bird](https://github.com/amosbird)).
+* Install script should always create subdirs in config folders. This is only relevant for Docker build with custom config. [#16936](https://github.com/ClickHouse/ClickHouse/pull/16936) ([filimonov](https://github.com/filimonov)).
+* Fix possible error `Illegal type of argument` for queries with `ORDER BY`. Fixes [#16580](https://github.com/ClickHouse/ClickHouse/issues/16580). [#16928](https://github.com/ClickHouse/ClickHouse/pull/16928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Abort multipart upload if no data was written to WriteBufferFromS3. [#16840](https://github.com/ClickHouse/ClickHouse/pull/16840) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fix crash when using `any` without any arguments. This is for [#16803](https://github.com/ClickHouse/ClickHouse/issues/16803) . cc @azat. [#16826](https://github.com/ClickHouse/ClickHouse/pull/16826) ([Amos Bird](https://github.com/amosbird)).
+* Fix `IN` operator over several columns and tuples with enabled `transform_null_in` setting. Fixes [#15310](https://github.com/ClickHouse/ClickHouse/issues/15310). [#16722](https://github.com/ClickHouse/ClickHouse/pull/16722) ([Anton Popov](https://github.com/CurtizJ)).
+* This will fix optimize_read_in_order/optimize_aggregation_in_order with max_threads>0 and expression in ORDER BY. [#16637](https://github.com/ClickHouse/ClickHouse/pull/16637) ([Azat Khuzhin](https://github.com/azat)).
+* fixes [#16574](https://github.com/ClickHouse/ClickHouse/issues/16574) fixes [#16231](https://github.com/ClickHouse/ClickHouse/issues/16231) fix remote query failure when using 'if' suffix aggregate function. [#16610](https://github.com/ClickHouse/ClickHouse/pull/16610) ([Winter Zhang](https://github.com/zhang2014)).
+* Query is finished faster in case of exception. Cancel execution on remote replicas if exception happens. [#15578](https://github.com/ClickHouse/ClickHouse/pull/15578) ([Azat Khuzhin](https://github.com/azat)).
+
+
+### ClickHouse release v20.9.5.5-stable, 2020-11-13
+
+#### Bug Fix
+
+* Fix rare silent crashes when query profiler is on and ClickHouse is installed on OS with glibc version that has (supposedly) broken asynchronous unwind tables for some functions. This fixes [#15301](https://github.com/ClickHouse/ClickHouse/issues/15301). This fixes [#13098](https://github.com/ClickHouse/ClickHouse/issues/13098). [#16846](https://github.com/ClickHouse/ClickHouse/pull/16846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now when parsing AVRO from input the LowCardinality is removed from type. Fixes [#16188](https://github.com/ClickHouse/ClickHouse/issues/16188). [#16521](https://github.com/ClickHouse/ClickHouse/pull/16521) ([Mike](https://github.com/myrrc)).
+* Fix rapid growth of metadata when using MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL Engine, and `slave_parallel_worker` enabled on MySQL Slave, by properly shrinking GTID sets. This fixes [#15951](https://github.com/ClickHouse/ClickHouse/issues/15951). [#16504](https://github.com/ClickHouse/ClickHouse/pull/16504) ([TCeason](https://github.com/TCeason)).
+* Fix DROP TABLE for Distributed (racy with INSERT). [#16409](https://github.com/ClickHouse/ClickHouse/pull/16409) ([Azat Khuzhin](https://github.com/azat)).
+* Fix processing of very large entries in replication queue. Very large entries may appear in ALTER queries if table structure is extremely large (near 1 MB). This fixes [#16307](https://github.com/ClickHouse/ClickHouse/issues/16307). [#16332](https://github.com/ClickHouse/ClickHouse/pull/16332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the inconsistent behaviour when a part of return data could be dropped because the set for its filtration wasn't created. [#16308](https://github.com/ClickHouse/ClickHouse/pull/16308) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix bug with MySQL database. When MySQL server used as database engine is down some queries raise Exception, because they try to get tables from disabled server, while it's unnecessary. For example, query `SELECT ... FROM system.parts` should work only with MergeTree tables and don't touch MySQL database at all. [#16032](https://github.com/ClickHouse/ClickHouse/pull/16032) ([Kruglov Pavel](https://github.com/Avogar)).
+
+
+### ClickHouse release v20.9.4.76-stable (2020-10-29)
+
+#### Bug Fix
+
+* Fix double free in case of exception in function `dictGet`. It could have happened if dictionary was loaded with error. [#16429](https://github.com/ClickHouse/ClickHouse/pull/16429) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix group by with totals/rollup/cube modifers and min/max functions over group by keys. Fixes [#16393](https://github.com/ClickHouse/ClickHouse/issues/16393). [#16397](https://github.com/ClickHouse/ClickHouse/pull/16397) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix async Distributed INSERT w/ prefer_localhost_replica=0 and internal_replication. [#16358](https://github.com/ClickHouse/ClickHouse/pull/16358) ([Azat Khuzhin](https://github.com/azat)).
+* Fix a very wrong code in TwoLevelStringHashTable implementation, which might lead to memory leak. I'm suprised how this bug can lurk for so long.... [#16264](https://github.com/ClickHouse/ClickHouse/pull/16264) ([Amos Bird](https://github.com/amosbird)).
+* Fix the case when memory can be overallocated regardless to the limit. This closes [#14560](https://github.com/ClickHouse/ClickHouse/issues/14560). [#16206](https://github.com/ClickHouse/ClickHouse/pull/16206) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `ALTER MODIFY ... ORDER BY` query hang for `ReplicatedVersionedCollapsingMergeTree`. This fixes [#15980](https://github.com/ClickHouse/ClickHouse/issues/15980). [#16011](https://github.com/ClickHouse/ClickHouse/pull/16011) ([alesapin](https://github.com/alesapin)).
+* Fix collate name & charset name parser and support `length = 0` for string type. [#16008](https://github.com/ClickHouse/ClickHouse/pull/16008) ([Winter Zhang](https://github.com/zhang2014)).
+* Allow to use direct layout for dictionaries with complex keys. [#16007](https://github.com/ClickHouse/ClickHouse/pull/16007) ([Anton Popov](https://github.com/CurtizJ)).
+* Prevent replica hang for 5-10 mins when replication error happens after a period of inactivity. [#15987](https://github.com/ClickHouse/ClickHouse/pull/15987) ([filimonov](https://github.com/filimonov)).
+* Fix rare segfaults when inserting into or selecting from MaterializedView and concurrently dropping target table (for Atomic database engine). [#15984](https://github.com/ClickHouse/ClickHouse/pull/15984) ([tavplubix](https://github.com/tavplubix)).
+* Fix ambiguity in parsing of settings profiles: `CREATE USER ... SETTINGS profile readonly` is now considered as using a profile named `readonly`, not a setting named `profile` with the readonly constraint. This fixes [#15628](https://github.com/ClickHouse/ClickHouse/issues/15628). [#15982](https://github.com/ClickHouse/ClickHouse/pull/15982) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix a crash when database creation fails. [#15954](https://github.com/ClickHouse/ClickHouse/pull/15954) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed `DROP TABLE IF EXISTS` failure with `Table ... does not exist` error when table is concurrently renamed (for Atomic database engine). Fixed rare deadlock when concurrently executing some DDL queries with multiple tables (like `DROP DATABASE` and `RENAME TABLE`) Fixed `DROP/DETACH DATABASE` failure with `Table ... does not exist` when concurrently executing `DROP/DETACH TABLE`. [#15934](https://github.com/ClickHouse/ClickHouse/pull/15934) ([tavplubix](https://github.com/tavplubix)).
+* Fix incorrect empty result for query from `Distributed` table if query has `WHERE`, `PREWHERE` and `GLOBAL IN`. Fixes [#15792](https://github.com/ClickHouse/ClickHouse/issues/15792). [#15933](https://github.com/ClickHouse/ClickHouse/pull/15933) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix possible deadlocks in RBAC. [#15875](https://github.com/ClickHouse/ClickHouse/pull/15875) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix exception `Block structure mismatch` in `SELECT ... ORDER BY DESC` queries which were executed after `ALTER MODIFY COLUMN` query. Fixes [#15800](https://github.com/ClickHouse/ClickHouse/issues/15800). [#15852](https://github.com/ClickHouse/ClickHouse/pull/15852) ([alesapin](https://github.com/alesapin)).
+* Fix `select count()` inaccuracy for MaterializeMySQL. [#15767](https://github.com/ClickHouse/ClickHouse/pull/15767) ([tavplubix](https://github.com/tavplubix)).
+* Fix some cases of queries, in which only virtual columns are selected. Previously `Not found column _nothing in block` exception may be thrown. Fixes [#12298](https://github.com/ClickHouse/ClickHouse/issues/12298). [#15756](https://github.com/ClickHouse/ClickHouse/pull/15756) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed too low default value of `max_replicated_logs_to_keep` setting, which might cause replicas to become lost too often. Improve lost replica recovery process by choosing the most up-to-date replica to clone. Also do not remove old parts from lost replica, detach them instead. [#15701](https://github.com/ClickHouse/ClickHouse/pull/15701) ([tavplubix](https://github.com/tavplubix)).
+* Fix error `Cannot add simple transform to empty Pipe` which happened while reading from `Buffer` table which has different structure than destination table. It was possible if destination table returned empty result for query. Fixes [#15529](https://github.com/ClickHouse/ClickHouse/issues/15529). [#15662](https://github.com/ClickHouse/ClickHouse/pull/15662) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed bug with globs in S3 table function, region from URL was not applied to S3 client configuration. [#15646](https://github.com/ClickHouse/ClickHouse/pull/15646) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Decrement the `ReadonlyReplica` metric when detaching read-only tables. This fixes [#15598](https://github.com/ClickHouse/ClickHouse/issues/15598). [#15592](https://github.com/ClickHouse/ClickHouse/pull/15592) ([sundyli](https://github.com/sundy-li)).
+* Throw an error when a single parameter is passed to ReplicatedMergeTree instead of ignoring it. [#15516](https://github.com/ClickHouse/ClickHouse/pull/15516) ([nvartolomei](https://github.com/nvartolomei)).
+
+#### Improvement
+
+* Now it's allowed to execute `ALTER ... ON CLUSTER` queries regardless of the `<internal_replication>` setting in cluster config. [#16075](https://github.com/ClickHouse/ClickHouse/pull/16075) ([alesapin](https://github.com/alesapin)).
+* Unfold `{database}`, `{table}` and `{uuid}` macros in `ReplicatedMergeTree` arguments on table creation. [#16160](https://github.com/ClickHouse/ClickHouse/pull/16160) ([tavplubix](https://github.com/tavplubix)).
+
+
+### ClickHouse release v20.9.3.45-stable (2020-10-09)
+
+#### Bug Fix
+
+* Fix error `Cannot find column` which may happen at insertion into `MATERIALIZED VIEW` in case if query for `MV` containes `ARRAY JOIN`. [#15717](https://github.com/ClickHouse/ClickHouse/pull/15717) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix race condition in AMQP-CPP. [#15667](https://github.com/ClickHouse/ClickHouse/pull/15667) ([alesapin](https://github.com/alesapin)).
+* Fix the order of destruction for resources in `ReadFromStorage` step of query plan. It might cause crashes in rare cases. Possibly connected with [#15610](https://github.com/ClickHouse/ClickHouse/issues/15610). [#15645](https://github.com/ClickHouse/ClickHouse/pull/15645) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed `Element ... is not a constant expression` error when using `JSON*` function result in `VALUES`, `LIMIT` or right side of `IN` operator. [#15589](https://github.com/ClickHouse/ClickHouse/pull/15589) ([tavplubix](https://github.com/tavplubix)).
+* Prevent the possibility of error message `Could not calculate available disk space (statvfs), errno: 4, strerror: Interrupted system call`. This fixes [#15541](https://github.com/ClickHouse/ClickHouse/issues/15541). [#15557](https://github.com/ClickHouse/ClickHouse/pull/15557) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Significantly reduce memory usage in AggregatingInOrderTransform/optimize_aggregation_in_order. [#15543](https://github.com/ClickHouse/ClickHouse/pull/15543) ([Azat Khuzhin](https://github.com/azat)).
+* Mutation might hang waiting for some non-existent part after `MOVE` or `REPLACE PARTITION` or, in rare cases, after `DETACH` or `DROP PARTITION`. It's fixed. [#15537](https://github.com/ClickHouse/ClickHouse/pull/15537) ([tavplubix](https://github.com/tavplubix)).
+* Fix bug when `ILIKE` operator stops being case insensitive if `LIKE` with the same pattern was executed. [#15536](https://github.com/ClickHouse/ClickHouse/pull/15536) ([alesapin](https://github.com/alesapin)).
+* Fix `Missing columns` errors when selecting columns which absent in data, but depend on other columns which also absent in data. Fixes [#15530](https://github.com/ClickHouse/ClickHouse/issues/15530). [#15532](https://github.com/ClickHouse/ClickHouse/pull/15532) ([alesapin](https://github.com/alesapin)).
+* Fix bug with event subscription in DDLWorker which rarely may lead to query hangs in `ON CLUSTER`. Introduced in [#13450](https://github.com/ClickHouse/ClickHouse/issues/13450). [#15477](https://github.com/ClickHouse/ClickHouse/pull/15477) ([alesapin](https://github.com/alesapin)).
+* Report proper error when the second argument of `boundingRatio` aggregate function has a wrong type. [#15407](https://github.com/ClickHouse/ClickHouse/pull/15407) ([detailyang](https://github.com/detailyang)).
+* Fix bug where queries like `SELECT toStartOfDay(today())` fail complaining about empty time_zone argument. [#15319](https://github.com/ClickHouse/ClickHouse/pull/15319) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix race condition during MergeTree table rename and background cleanup. [#15304](https://github.com/ClickHouse/ClickHouse/pull/15304) ([alesapin](https://github.com/alesapin)).
+* Fix rare race condition on server startup when system.logs are enabled. [#15300](https://github.com/ClickHouse/ClickHouse/pull/15300) ([alesapin](https://github.com/alesapin)).
+* Fix MSan report in QueryLog. Uninitialized memory can be used for the field `memory_usage`. [#15258](https://github.com/ClickHouse/ClickHouse/pull/15258) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix instance crash when using joinGet with LowCardinality types. This fixes [#15214](https://github.com/ClickHouse/ClickHouse/issues/15214). [#15220](https://github.com/ClickHouse/ClickHouse/pull/15220) ([Amos Bird](https://github.com/amosbird)).
+* Fix bug in table engine `Buffer` which does not allow to insert data of new structure into `Buffer` after `ALTER` query. Fixes [#15117](https://github.com/ClickHouse/ClickHouse/issues/15117). [#15192](https://github.com/ClickHouse/ClickHouse/pull/15192) ([alesapin](https://github.com/alesapin)).
+* Adjust decimals field size in mysql column definition packet. [#15152](https://github.com/ClickHouse/ClickHouse/pull/15152) ([maqroll](https://github.com/maqroll)).
+* Fixed `Cannot rename ... errno: 22, strerror: Invalid argument` error on DDL query execution in Atomic database when running clickhouse-server in docker on Mac OS. [#15024](https://github.com/ClickHouse/ClickHouse/pull/15024) ([tavplubix](https://github.com/tavplubix)).
+* Fix to make predicate push down work when subquery contains finalizeAggregation function. Fixes [#14847](https://github.com/ClickHouse/ClickHouse/issues/14847). [#14937](https://github.com/ClickHouse/ClickHouse/pull/14937) ([filimonov](https://github.com/filimonov)).
+* Fix a problem where the server may get stuck on startup while talking to ZooKeeper, if the configuration files have to be fetched from ZK (using the `from_zk` include option). This fixes [#14814](https://github.com/ClickHouse/ClickHouse/issues/14814). [#14843](https://github.com/ClickHouse/ClickHouse/pull/14843) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+
+#### Improvement
+
+* Now it's possible to change the type of version column for `VersionedCollapsingMergeTree` with `ALTER` query. [#15442](https://github.com/ClickHouse/ClickHouse/pull/15442) ([alesapin](https://github.com/alesapin)).
+
+
+### ClickHouse release v20.9.2.20, 2020-09-22
+
+#### Backward Incompatible Change
+
+* When upgrading from versions older than 20.5, if rolling update is performed and cluster contains both versions 20.5 or greater and less than 20.5, if ClickHouse nodes with old versions are restarted and old version has been started up in presence of newer versions, it may lead to `Part ... intersects previous part` errors. To prevent this error, first install newer clickhouse-server packages on all cluster nodes and then do restarts (so, when clickhouse-server is restarted, it will start up with the new version).
+
+#### New Feature
+
+* Added column transformers `EXCEPT`, `REPLACE`, `APPLY`, which can be applied to the list of selected columns (after `*` or `COLUMNS(...)`). For example, you can write `SELECT * EXCEPT(URL) REPLACE(number + 1 AS number)`. Another example: `select * apply(length) apply(max) from wide_string_table` to find out the maxium length of all string columns. [#14233](https://github.com/ClickHouse/ClickHouse/pull/14233) ([Amos Bird](https://github.com/amosbird)).
+* Added an aggregate function `rankCorr` which computes a rank correlation coefficient. [#11769](https://github.com/ClickHouse/ClickHouse/pull/11769) ([antikvist](https://github.com/antikvist)) [#14411](https://github.com/ClickHouse/ClickHouse/pull/14411) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Added table function `view` which turns a subquery into a table object. This helps passing queries around. For instance, it can be used in remote/cluster table functions. [#12567](https://github.com/ClickHouse/ClickHouse/pull/12567) ([Amos Bird](https://github.com/amosbird)).
+
+#### Bug Fix
+
+* Fix bug when `ALTER UPDATE` mutation with Nullable column in assignment expression and constant value (like `UPDATE x = 42`) leads to incorrect value in column or segfault. Fixes [#13634](https://github.com/ClickHouse/ClickHouse/issues/13634), [#14045](https://github.com/ClickHouse/ClickHouse/issues/14045). [#14646](https://github.com/ClickHouse/ClickHouse/pull/14646) ([alesapin](https://github.com/alesapin)).
+* Fix wrong Decimal multiplication result caused wrong decimal scale of result column. [#14603](https://github.com/ClickHouse/ClickHouse/pull/14603) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixed the incorrect sorting order of `Nullable` column. This fixes [#14344](https://github.com/ClickHouse/ClickHouse/issues/14344). [#14495](https://github.com/ClickHouse/ClickHouse/pull/14495) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed inconsistent comparison with primary key of type `FixedString` on index analysis if they're compered with a string of less size. This fixes [#14908](https://github.com/ClickHouse/ClickHouse/issues/14908). [#15033](https://github.com/ClickHouse/ClickHouse/pull/15033) ([Amos Bird](https://github.com/amosbird)).
+* Fix bug which leads to wrong merges assignment if table has partitions with a single part. [#14444](https://github.com/ClickHouse/ClickHouse/pull/14444) ([alesapin](https://github.com/alesapin)).
+* If function `bar` was called with specifically crafted arguments, buffer overflow was possible. This closes [#13926](https://github.com/ClickHouse/ClickHouse/issues/13926). [#15028](https://github.com/ClickHouse/ClickHouse/pull/15028) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Publish CPU frequencies per logical core in `system.asynchronous_metrics`. This fixes [#14923](https://github.com/ClickHouse/ClickHouse/issues/14923). [#14924](https://github.com/ClickHouse/ClickHouse/pull/14924) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fixed `.metadata.tmp File exists` error when using `MaterializeMySQL` database engine. [#14898](https://github.com/ClickHouse/ClickHouse/pull/14898) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix the issue when some invocations of `extractAllGroups` function may trigger "Memory limit exceeded" error. This fixes [#13383](https://github.com/ClickHouse/ClickHouse/issues/13383). [#14889](https://github.com/ClickHouse/ClickHouse/pull/14889) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix SIGSEGV for an attempt to INSERT into StorageFile(fd). [#14887](https://github.com/ClickHouse/ClickHouse/pull/14887) ([Azat Khuzhin](https://github.com/azat)).
+* Fix rare error in `SELECT` queries when the queried column has `DEFAULT` expression which depends on the other column which also has `DEFAULT` and not present in select query and not exists on disk. Partially fixes [#14531](https://github.com/ClickHouse/ClickHouse/issues/14531). [#14845](https://github.com/ClickHouse/ClickHouse/pull/14845) ([alesapin](https://github.com/alesapin)).
+* Fix wrong monotonicity detection for shrunk `Int -> Int` cast of signed types. It might lead to incorrect query result. This bug is unveiled in [#14513](https://github.com/ClickHouse/ClickHouse/issues/14513). [#14783](https://github.com/ClickHouse/ClickHouse/pull/14783) ([Amos Bird](https://github.com/amosbird)).
+* Fixed missed default database name in metadata of materialized view when executing `ALTER ... MODIFY QUERY`. [#14664](https://github.com/ClickHouse/ClickHouse/pull/14664) ([tavplubix](https://github.com/tavplubix)).
+* Fix possibly incorrect result of function `has` when LowCardinality and Nullable types are involved. [#14591](https://github.com/ClickHouse/ClickHouse/pull/14591) ([Mike](https://github.com/myrrc)).
+* Cleanup data directory after Zookeeper exceptions during CREATE query for tables with ReplicatedMergeTree Engine. [#14563](https://github.com/ClickHouse/ClickHouse/pull/14563) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix rare segfaults in functions with combinator `-Resample`, which could appear in result of overflow with very large parameters. [#14562](https://github.com/ClickHouse/ClickHouse/pull/14562) ([Anton Popov](https://github.com/CurtizJ)).
+* Check for array size overflow in `topK` aggregate function. Without this check the user may send a query with carefully crafted parameters that will lead to server crash. This closes [#14452](https://github.com/ClickHouse/ClickHouse/issues/14452). [#14467](https://github.com/ClickHouse/ClickHouse/pull/14467) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Proxy restart/start/stop/reload of SysVinit to systemd (if it is used). [#14460](https://github.com/ClickHouse/ClickHouse/pull/14460) ([Azat Khuzhin](https://github.com/azat)).
+* Stop query execution if exception happened in `PipelineExecutor` itself. This could prevent rare possible query hung. [#14334](https://github.com/ClickHouse/ClickHouse/pull/14334) [#14402](https://github.com/ClickHouse/ClickHouse/pull/14402) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix crash during `ALTER` query for table which was created `AS table_function`. Fixes [#14212](https://github.com/ClickHouse/ClickHouse/issues/14212). [#14326](https://github.com/ClickHouse/ClickHouse/pull/14326) ([alesapin](https://github.com/alesapin)).
+* Fix exception during ALTER LIVE VIEW query with REFRESH command. LIVE VIEW is an experimental feature. [#14320](https://github.com/ClickHouse/ClickHouse/pull/14320) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix QueryPlan lifetime (for EXPLAIN PIPELINE graph=1) for queries with nested interpreter. [#14315](https://github.com/ClickHouse/ClickHouse/pull/14315) ([Azat Khuzhin](https://github.com/azat)).
+* Better check for tuple size in SSD cache complex key external dictionaries. This fixes [#13981](https://github.com/ClickHouse/ClickHouse/issues/13981). [#14313](https://github.com/ClickHouse/ClickHouse/pull/14313) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Disallows `CODEC` on `ALIAS` column type. Fixes [#13911](https://github.com/ClickHouse/ClickHouse/issues/13911). [#14263](https://github.com/ClickHouse/ClickHouse/pull/14263) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix GRANT ALL statement when executed on a non-global level. [#13987](https://github.com/ClickHouse/ClickHouse/pull/13987) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix arrayJoin() capturing in lambda (exception with logical error message was thrown). [#13792](https://github.com/ClickHouse/ClickHouse/pull/13792) ([Azat Khuzhin](https://github.com/azat)).
+
+#### Experimental Feature
+
+* Added `db-generator` tool for random database generation by given SELECT queries. It may faciliate reproducing issues when there is only incomplete bug report from the user. [#14442](https://github.com/ClickHouse/ClickHouse/pull/14442) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)) [#10973](https://github.com/ClickHouse/ClickHouse/issues/10973) ([ZeDRoman](https://github.com/ZeDRoman)).
+
+#### Improvement
+
+* Allow using multi-volume storage configuration in storage Distributed. [#14839](https://github.com/ClickHouse/ClickHouse/pull/14839) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Disallow empty time_zone argument in `toStartOf*` type of functions. [#14509](https://github.com/ClickHouse/ClickHouse/pull/14509) ([Bharat Nallan](https://github.com/bharatnc)).
+* MySQL handler returns `OK` for queries like `SET @@var = value`. Such statement is ignored. It is needed because some MySQL drivers send `SET @@` query for setup after handshake https://github.com/ClickHouse/ClickHouse/issues/9336#issuecomment-686222422 . [#14469](https://github.com/ClickHouse/ClickHouse/pull/14469) ([BohuTANG](https://github.com/BohuTANG)).
+* Now TTLs will be applied during merge if they were not previously materialized. [#14438](https://github.com/ClickHouse/ClickHouse/pull/14438) ([alesapin](https://github.com/alesapin)).
+* Now `clickhouse-obfuscator` supports UUID type as proposed in [#13163](https://github.com/ClickHouse/ClickHouse/issues/13163). [#14409](https://github.com/ClickHouse/ClickHouse/pull/14409) ([dimarub2000](https://github.com/dimarub2000)).
+* Added new setting `system_events_show_zero_values` as proposed in [#11384](https://github.com/ClickHouse/ClickHouse/issues/11384). [#14404](https://github.com/ClickHouse/ClickHouse/pull/14404) ([dimarub2000](https://github.com/dimarub2000)).
+* Implicitly convert primary key to not null in `MaterializeMySQL` (Same as `MySQL`). Fixes [#14114](https://github.com/ClickHouse/ClickHouse/issues/14114). [#14397](https://github.com/ClickHouse/ClickHouse/pull/14397) ([Winter Zhang](https://github.com/zhang2014)).
+* Replace wide integers (256 bit) from boost multiprecision with implementation from https://github.com/cerevra/int. 256bit integers are experimental. [#14229](https://github.com/ClickHouse/ClickHouse/pull/14229) ([Artem Zuikov](https://github.com/4ertus2)).
+* Add default compression codec for parts in `system.part_log` with the name `default_compression_codec`. [#14116](https://github.com/ClickHouse/ClickHouse/pull/14116) ([alesapin](https://github.com/alesapin)).
+* Add precision argument for `DateTime` type. It allows to use `DateTime` name instead of `DateTime64`. [#13761](https://github.com/ClickHouse/ClickHouse/pull/13761) ([Winter Zhang](https://github.com/zhang2014)).
+* Added requirepass authorization for `Redis` external dictionary. [#13688](https://github.com/ClickHouse/ClickHouse/pull/13688) ([Ivan Torgashov](https://github.com/it1804)).
+* Improvements in `RabbitMQ` engine: added connection and channels failure handling, proper commits, insert failures handling, better exchanges, queue durability and queue resume opportunity, new queue settings. Fixed tests. [#12761](https://github.com/ClickHouse/ClickHouse/pull/12761) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Support custom codecs in compact parts. [#12183](https://github.com/ClickHouse/ClickHouse/pull/12183) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Performance Improvement
+
+* Optimize queries with LIMIT/LIMIT BY/ORDER BY for distributed with GROUP BY sharding_key (under `optimize_skip_unused_shards` and `optimize_distributed_group_by_sharding_key`). [#10373](https://github.com/ClickHouse/ClickHouse/pull/10373) ([Azat Khuzhin](https://github.com/azat)).
+* Creating sets for multiple `JOIN` and `IN` in parallel. It may slightly improve performance for queries with several different `IN subquery` expressions. [#14412](https://github.com/ClickHouse/ClickHouse/pull/14412) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Improve Kafka engine performance by providing independent thread for each consumer. Separate thread pool for streaming engines (like Kafka). [#13939](https://github.com/ClickHouse/ClickHouse/pull/13939) ([fastio](https://github.com/fastio)).
+
+#### Build/Testing/Packaging Improvement
+
+* Lower binary size in debug build by removing debug info from `Functions`. This is needed only for one internal project in Yandex who is using very old linker. [#14549](https://github.com/ClickHouse/ClickHouse/pull/14549) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Prepare for build with clang 11. [#14455](https://github.com/ClickHouse/ClickHouse/pull/14455) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix the logic in backport script. In previous versions it was triggered for any labels of 100% red color. It was strange. [#14433](https://github.com/ClickHouse/ClickHouse/pull/14433) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Integration tests use default base config. All config changes are explicit with main_configs, user_configs and dictionaries parameters for instance. [#13647](https://github.com/ClickHouse/ClickHouse/pull/13647) ([Ilya Yatsishin](https://github.com/qoega)).
+
+
+
+## ClickHouse release 20.8
+
+### ClickHouse release v20.8.12.2-lts, 2021-01-16
+
+#### Bug Fix
+
+* Fix *If combinator with unary function and Nullable types. [#18806](https://github.com/ClickHouse/ClickHouse/pull/18806) ([Azat Khuzhin](https://github.com/azat)).
+* Restrict merges from wide to compact parts. In case of vertical merge it led to broken result part. [#18381](https://github.com/ClickHouse/ClickHouse/pull/18381) ([Anton Popov](https://github.com/CurtizJ)).
+
+
+### ClickHouse release v20.8.11.17-lts, 2020-12-25
+
+#### Bug Fix
+
+* Disable write with AIO during merges because it can lead to extremely rare data corruption of primary key columns during merge. [#18481](https://github.com/ClickHouse/ClickHouse/pull/18481) ([alesapin](https://github.com/alesapin)).
+* Fixed `value is too short` error when executing `toType(...)` functions (`toDate`, `toUInt32`, etc) with argument of type `Nullable(String)`. Now such functions return `NULL` on parsing errors instead of throwing exception. Fixes [#7673](https://github.com/ClickHouse/ClickHouse/issues/7673). [#18445](https://github.com/ClickHouse/ClickHouse/pull/18445) ([tavplubix](https://github.com/tavplubix)).
+* Fix possible crashes in aggregate functions with combinator `Distinct`, while using two-level aggregation. Fixes [#17682](https://github.com/ClickHouse/ClickHouse/issues/17682). [#18365](https://github.com/ClickHouse/ClickHouse/pull/18365) ([Anton Popov](https://github.com/CurtizJ)).
+
+
+### ClickHouse release v20.8.10.13-lts, 2020-12-24
+
+#### Bug Fix
+
+* When server log rotation was configured using `logger.size` parameter with numeric value larger than 2^32, the logs were not rotated properly. [#17905](https://github.com/ClickHouse/ClickHouse/pull/17905) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fixed incorrect initialization of `max_compress_block_size` in MergeTreeWriterSettings with `min_compress_block_size`. [#17833](https://github.com/ClickHouse/ClickHouse/pull/17833) ([flynn](https://github.com/ucasFL)).
+* Fixed problem when ClickHouse fails to resume connection to MySQL servers. [#17681](https://github.com/ClickHouse/ClickHouse/pull/17681) ([Alexander Kazakov](https://github.com/Akazz)).
+* Fixed `ALTER` query hang when the corresponding mutation was killed on the different replica. This fixes [#16953](https://github.com/ClickHouse/ClickHouse/issues/16953). [#17499](https://github.com/ClickHouse/ClickHouse/pull/17499) ([alesapin](https://github.com/alesapin)).
+* Fixed a bug when mark cache size was underestimated by ClickHouse. It may happen when there are a lot of tiny files with marks. [#17496](https://github.com/ClickHouse/ClickHouse/pull/17496) ([alesapin](https://github.com/alesapin)).
+* Fixed `ORDER BY` with enabled setting `optimize_redundant_functions_in_order_by`. [#17471](https://github.com/ClickHouse/ClickHouse/pull/17471) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed `ColumnConst` comparison which leads to crash. This fixed [#17088](https://github.com/ClickHouse/ClickHouse/issues/17088) . [#17135](https://github.com/ClickHouse/ClickHouse/pull/17135) ([Amos Bird](https://github.com/amosbird)).
+* Fixed bug when `ON CLUSTER` queries may hang forever for non-leader ReplicatedMergeTreeTables. [#17089](https://github.com/ClickHouse/ClickHouse/pull/17089) ([alesapin](https://github.com/alesapin)).
+* Avoid unnecessary network errors for remote queries which may be cancelled while execution, like queries with `LIMIT`. [#17006](https://github.com/ClickHouse/ClickHouse/pull/17006) ([Azat Khuzhin](https://github.com/azat)).
+* Reresolve the IP of the `format_avro_schema_registry_url` in case of errors. [#16985](https://github.com/ClickHouse/ClickHouse/pull/16985) ([filimonov](https://github.com/filimonov)).
+* Fixed possible server crash after `ALTER TABLE ... MODIFY COLUMN ... NewType` when `SELECT` have `WHERE` expression on altering column and alter does not finished yet. [#16968](https://github.com/ClickHouse/ClickHouse/pull/16968) ([Amos Bird](https://github.com/amosbird)).
+* Install script should always create subdirs in config folders. This is only relevant for Docker build with custom config. [#16936](https://github.com/ClickHouse/ClickHouse/pull/16936) ([filimonov](https://github.com/filimonov)).
+* Fixed possible error `Illegal type of argument` for queries with `ORDER BY`. Fixes [#16580](https://github.com/ClickHouse/ClickHouse/issues/16580). [#16928](https://github.com/ClickHouse/ClickHouse/pull/16928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Abort multipart upload if no data was written to WriteBufferFromS3. [#16840](https://github.com/ClickHouse/ClickHouse/pull/16840) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fixed crash when using `any` without any arguments. This fixes [#16803](https://github.com/ClickHouse/ClickHouse/issues/16803). [#16826](https://github.com/ClickHouse/ClickHouse/pull/16826) ([Amos Bird](https://github.com/amosbird)).
+* Fixed `IN` operator over several columns and tuples with enabled `transform_null_in` setting. Fixes [#15310](https://github.com/ClickHouse/ClickHouse/issues/15310). [#16722](https://github.com/ClickHouse/ClickHouse/pull/16722) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed inconsistent behaviour of `optimize_read_in_order/optimize_aggregation_in_order` with max_threads > 0 and expression in ORDER BY. [#16637](https://github.com/ClickHouse/ClickHouse/pull/16637) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed the issue when query optimization was producing wrong result if query contains `ARRAY JOIN`. [#17887](https://github.com/ClickHouse/ClickHouse/pull/17887) ([sundyli](https://github.com/sundy-li)).
+* Query is finished faster in case of exception. Cancel execution on remote replicas if exception happens. [#15578](https://github.com/ClickHouse/ClickHouse/pull/15578) ([Azat Khuzhin](https://github.com/azat)).
+
+
+### ClickHouse release v20.8.6.6-lts, 2020-11-13
+
+#### Bug Fix
+
+* Fix rare silent crashes when query profiler is on and ClickHouse is installed on OS with glibc version that has (supposedly) broken asynchronous unwind tables for some functions. This fixes [#15301](https://github.com/ClickHouse/ClickHouse/issues/15301). This fixes [#13098](https://github.com/ClickHouse/ClickHouse/issues/13098). [#16846](https://github.com/ClickHouse/ClickHouse/pull/16846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now when parsing AVRO from input the LowCardinality is removed from type. Fixes [#16188](https://github.com/ClickHouse/ClickHouse/issues/16188). [#16521](https://github.com/ClickHouse/ClickHouse/pull/16521) ([Mike](https://github.com/myrrc)).
+* Fix rapid growth of metadata when using MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL Engine, and `slave_parallel_worker` enabled on MySQL Slave, by properly shrinking GTID sets. This fixes [#15951](https://github.com/ClickHouse/ClickHouse/issues/15951). [#16504](https://github.com/ClickHouse/ClickHouse/pull/16504) ([TCeason](https://github.com/TCeason)).
+* Fix DROP TABLE for Distributed (racy with INSERT). [#16409](https://github.com/ClickHouse/ClickHouse/pull/16409) ([Azat Khuzhin](https://github.com/azat)).
+* Fix processing of very large entries in replication queue. Very large entries may appear in ALTER queries if table structure is extremely large (near 1 MB). This fixes [#16307](https://github.com/ClickHouse/ClickHouse/issues/16307). [#16332](https://github.com/ClickHouse/ClickHouse/pull/16332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the inconsistent behaviour when a part of return data could be dropped because the set for its filtration wasn't created. [#16308](https://github.com/ClickHouse/ClickHouse/pull/16308) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix bug with MySQL database. When MySQL server used as database engine is down some queries raise Exception, because they try to get tables from disabled server, while it's unnecessary. For example, query `SELECT ... FROM system.parts` should work only with MergeTree tables and don't touch MySQL database at all. [#16032](https://github.com/ClickHouse/ClickHouse/pull/16032) ([Kruglov Pavel](https://github.com/Avogar)).
+
+
+### ClickHouse release v20.8.5.45-lts, 2020-10-29
+
+#### Bug Fix
+
+* Fix double free in case of exception in function `dictGet`. It could have happened if dictionary was loaded with error. [#16429](https://github.com/ClickHouse/ClickHouse/pull/16429) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix group by with totals/rollup/cube modifers and min/max functions over group by keys. Fixes [#16393](https://github.com/ClickHouse/ClickHouse/issues/16393). [#16397](https://github.com/ClickHouse/ClickHouse/pull/16397) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix async Distributed INSERT w/ prefer_localhost_replica=0 and internal_replication. [#16358](https://github.com/ClickHouse/ClickHouse/pull/16358) ([Azat Khuzhin](https://github.com/azat)).
+* Fix a possible memory leak during `GROUP BY` with string keys, caused by an error in `TwoLevelStringHashTable` implementation. [#16264](https://github.com/ClickHouse/ClickHouse/pull/16264) ([Amos Bird](https://github.com/amosbird)).
+* Fix the case when memory can be overallocated regardless to the limit. This closes [#14560](https://github.com/ClickHouse/ClickHouse/issues/14560). [#16206](https://github.com/ClickHouse/ClickHouse/pull/16206) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `ALTER MODIFY ... ORDER BY` query hang for `ReplicatedVersionedCollapsingMergeTree`. This fixes [#15980](https://github.com/ClickHouse/ClickHouse/issues/15980). [#16011](https://github.com/ClickHouse/ClickHouse/pull/16011) ([alesapin](https://github.com/alesapin)).
+* Fix collate name & charset name parser and support `length = 0` for string type. [#16008](https://github.com/ClickHouse/ClickHouse/pull/16008) ([Winter Zhang](https://github.com/zhang2014)).
+* Allow to use direct layout for dictionaries with complex keys. [#16007](https://github.com/ClickHouse/ClickHouse/pull/16007) ([Anton Popov](https://github.com/CurtizJ)).
+* Prevent replica hang for 5-10 mins when replication error happens after a period of inactivity. [#15987](https://github.com/ClickHouse/ClickHouse/pull/15987) ([filimonov](https://github.com/filimonov)).
+* Fix rare segfaults when inserting into or selecting from MaterializedView and concurrently dropping target table (for Atomic database engine). [#15984](https://github.com/ClickHouse/ClickHouse/pull/15984) ([tavplubix](https://github.com/tavplubix)).
+* Fix ambiguity in parsing of settings profiles: `CREATE USER ... SETTINGS profile readonly` is now considered as using a profile named `readonly`, not a setting named `profile` with the readonly constraint. This fixes [#15628](https://github.com/ClickHouse/ClickHouse/issues/15628). [#15982](https://github.com/ClickHouse/ClickHouse/pull/15982) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix a crash when database creation fails. [#15954](https://github.com/ClickHouse/ClickHouse/pull/15954) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed `DROP TABLE IF EXISTS` failure with `Table ... does not exist` error when table is concurrently renamed (for Atomic database engine). Fixed rare deadlock when concurrently executing some DDL queries with multiple tables (like `DROP DATABASE` and `RENAME TABLE`) Fixed `DROP/DETACH DATABASE` failure with `Table ... does not exist` when concurrently executing `DROP/DETACH TABLE`. [#15934](https://github.com/ClickHouse/ClickHouse/pull/15934) ([tavplubix](https://github.com/tavplubix)).
+* Fix incorrect empty result for query from `Distributed` table if query has `WHERE`, `PREWHERE` and `GLOBAL IN`. Fixes [#15792](https://github.com/ClickHouse/ClickHouse/issues/15792). [#15933](https://github.com/ClickHouse/ClickHouse/pull/15933) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix possible deadlocks in RBAC. [#15875](https://github.com/ClickHouse/ClickHouse/pull/15875) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix exception `Block structure mismatch` in `SELECT ... ORDER BY DESC` queries which were executed after `ALTER MODIFY COLUMN` query. Fixes [#15800](https://github.com/ClickHouse/ClickHouse/issues/15800). [#15852](https://github.com/ClickHouse/ClickHouse/pull/15852) ([alesapin](https://github.com/alesapin)).
+* Fix some cases of queries, in which only virtual columns are selected. Previously `Not found column _nothing in block` exception may be thrown. Fixes [#12298](https://github.com/ClickHouse/ClickHouse/issues/12298). [#15756](https://github.com/ClickHouse/ClickHouse/pull/15756) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix error `Cannot find column` which may happen at insertion into `MATERIALIZED VIEW` in case if query for `MV` containes `ARRAY JOIN`. [#15717](https://github.com/ClickHouse/ClickHouse/pull/15717) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed too low default value of `max_replicated_logs_to_keep` setting, which might cause replicas to become lost too often. Improve lost replica recovery process by choosing the most up-to-date replica to clone. Also do not remove old parts from lost replica, detach them instead. [#15701](https://github.com/ClickHouse/ClickHouse/pull/15701) ([tavplubix](https://github.com/tavplubix)).
+* Fix error `Cannot add simple transform to empty Pipe` which happened while reading from `Buffer` table which has different structure than destination table. It was possible if destination table returned empty result for query. Fixes [#15529](https://github.com/ClickHouse/ClickHouse/issues/15529). [#15662](https://github.com/ClickHouse/ClickHouse/pull/15662) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed bug with globs in S3 table function, region from URL was not applied to S3 client configuration. [#15646](https://github.com/ClickHouse/ClickHouse/pull/15646) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Decrement the `ReadonlyReplica` metric when detaching read-only tables. This fixes [#15598](https://github.com/ClickHouse/ClickHouse/issues/15598). [#15592](https://github.com/ClickHouse/ClickHouse/pull/15592) ([sundyli](https://github.com/sundy-li)).
+* Throw an error when a single parameter is passed to ReplicatedMergeTree instead of ignoring it. [#15516](https://github.com/ClickHouse/ClickHouse/pull/15516) ([nvartolomei](https://github.com/nvartolomei)).
+
+#### Improvement
+
+* Now it's allowed to execute `ALTER ... ON CLUSTER` queries regardless of the `<internal_replication>` setting in cluster config. [#16075](https://github.com/ClickHouse/ClickHouse/pull/16075) ([alesapin](https://github.com/alesapin)).
+* Unfold `{database}`, `{table}` and `{uuid}` macros in `ReplicatedMergeTree` arguments on table creation. [#16159](https://github.com/ClickHouse/ClickHouse/pull/16159) ([tavplubix](https://github.com/tavplubix)).
+
+
+### ClickHouse release v20.8.4.11-lts, 2020-10-09
+
+#### Bug Fix
+
+* Fix the order of destruction for resources in `ReadFromStorage` step of query plan. It might cause crashes in rare cases. Possibly connected with [#15610](https://github.com/ClickHouse/ClickHouse/issues/15610). [#15645](https://github.com/ClickHouse/ClickHouse/pull/15645) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed `Element ... is not a constant expression` error when using `JSON*` function result in `VALUES`, `LIMIT` or right side of `IN` operator. [#15589](https://github.com/ClickHouse/ClickHouse/pull/15589) ([tavplubix](https://github.com/tavplubix)).
+* Prevent the possibility of error message `Could not calculate available disk space (statvfs), errno: 4, strerror: Interrupted system call`. This fixes [#15541](https://github.com/ClickHouse/ClickHouse/issues/15541). [#15557](https://github.com/ClickHouse/ClickHouse/pull/15557) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Significantly reduce memory usage in AggregatingInOrderTransform/optimize_aggregation_in_order. [#15543](https://github.com/ClickHouse/ClickHouse/pull/15543) ([Azat Khuzhin](https://github.com/azat)).
+* Mutation might hang waiting for some non-existent part after `MOVE` or `REPLACE PARTITION` or, in rare cases, after `DETACH` or `DROP PARTITION`. It's fixed. [#15537](https://github.com/ClickHouse/ClickHouse/pull/15537) ([tavplubix](https://github.com/tavplubix)).
+* Fix bug when `ILIKE` operator stops being case insensitive if `LIKE` with the same pattern was executed. [#15536](https://github.com/ClickHouse/ClickHouse/pull/15536) ([alesapin](https://github.com/alesapin)).
+* Fix `Missing columns` errors when selecting columns which absent in data, but depend on other columns which also absent in data. Fixes [#15530](https://github.com/ClickHouse/ClickHouse/issues/15530). [#15532](https://github.com/ClickHouse/ClickHouse/pull/15532) ([alesapin](https://github.com/alesapin)).
+* Fix bug with event subscription in DDLWorker which rarely may lead to query hangs in `ON CLUSTER`. Introduced in [#13450](https://github.com/ClickHouse/ClickHouse/issues/13450). [#15477](https://github.com/ClickHouse/ClickHouse/pull/15477) ([alesapin](https://github.com/alesapin)).
+* Report proper error when the second argument of `boundingRatio` aggregate function has a wrong type. [#15407](https://github.com/ClickHouse/ClickHouse/pull/15407) ([detailyang](https://github.com/detailyang)).
+* Fix race condition during MergeTree table rename and background cleanup. [#15304](https://github.com/ClickHouse/ClickHouse/pull/15304) ([alesapin](https://github.com/alesapin)).
+* Fix rare race condition on server startup when system.logs are enabled. [#15300](https://github.com/ClickHouse/ClickHouse/pull/15300) ([alesapin](https://github.com/alesapin)).
+* Fix MSan report in QueryLog. Uninitialized memory can be used for the field `memory_usage`. [#15258](https://github.com/ClickHouse/ClickHouse/pull/15258) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix instance crash when using joinGet with LowCardinality types. This fixes [#15214](https://github.com/ClickHouse/ClickHouse/issues/15214). [#15220](https://github.com/ClickHouse/ClickHouse/pull/15220) ([Amos Bird](https://github.com/amosbird)).
+* Fix bug in table engine `Buffer` which does not allow to insert data of new structure into `Buffer` after `ALTER` query. Fixes [#15117](https://github.com/ClickHouse/ClickHouse/issues/15117). [#15192](https://github.com/ClickHouse/ClickHouse/pull/15192) ([alesapin](https://github.com/alesapin)).
+* Adjust decimals field size in mysql column definition packet. [#15152](https://github.com/ClickHouse/ClickHouse/pull/15152) ([maqroll](https://github.com/maqroll)).
+* We already use padded comparison between String and FixedString (https://github.com/ClickHouse/ClickHouse/blob/master/src/Functions/FunctionsComparison.h#L333). This PR applies the same logic to field comparison which corrects the usage of FixedString as primary keys. This fixes [#14908](https://github.com/ClickHouse/ClickHouse/issues/14908). [#15033](https://github.com/ClickHouse/ClickHouse/pull/15033) ([Amos Bird](https://github.com/amosbird)).
+* If function `bar` was called with specifically crafted arguments, buffer overflow was possible. This closes [#13926](https://github.com/ClickHouse/ClickHouse/issues/13926). [#15028](https://github.com/ClickHouse/ClickHouse/pull/15028) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `Cannot rename ... errno: 22, strerror: Invalid argument` error on DDL query execution in Atomic database when running clickhouse-server in docker on Mac OS. [#15024](https://github.com/ClickHouse/ClickHouse/pull/15024) ([tavplubix](https://github.com/tavplubix)).
+* Now settings `number_of_free_entries_in_pool_to_execute_mutation` and `number_of_free_entries_in_pool_to_lower_max_size_of_merge` can be equal to `background_pool_size`. [#14975](https://github.com/ClickHouse/ClickHouse/pull/14975) ([alesapin](https://github.com/alesapin)).
+* Fix to make predicate push down work when subquery contains finalizeAggregation function. Fixes [#14847](https://github.com/ClickHouse/ClickHouse/issues/14847). [#14937](https://github.com/ClickHouse/ClickHouse/pull/14937) ([filimonov](https://github.com/filimonov)).
+* Publish CPU frequencies per logical core in `system.asynchronous_metrics`. This fixes [#14923](https://github.com/ClickHouse/ClickHouse/issues/14923). [#14924](https://github.com/ClickHouse/ClickHouse/pull/14924) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fixed `.metadata.tmp File exists` error when using `MaterializeMySQL` database engine. [#14898](https://github.com/ClickHouse/ClickHouse/pull/14898) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix a problem where the server may get stuck on startup while talking to ZooKeeper, if the configuration files have to be fetched from ZK (using the `from_zk` include option). This fixes [#14814](https://github.com/ClickHouse/ClickHouse/issues/14814). [#14843](https://github.com/ClickHouse/ClickHouse/pull/14843) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fix wrong monotonicity detection for shrunk `Int -> Int` cast of signed types. It might lead to incorrect query result. This bug is unveiled in [#14513](https://github.com/ClickHouse/ClickHouse/issues/14513). [#14783](https://github.com/ClickHouse/ClickHouse/pull/14783) ([Amos Bird](https://github.com/amosbird)).
+* Fixed the incorrect sorting order of `Nullable` column. This fixes [#14344](https://github.com/ClickHouse/ClickHouse/issues/14344). [#14495](https://github.com/ClickHouse/ClickHouse/pull/14495) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+
+#### Improvement
+
+* Now it's possible to change the type of version column for `VersionedCollapsingMergeTree` with `ALTER` query. [#15442](https://github.com/ClickHouse/ClickHouse/pull/15442) ([alesapin](https://github.com/alesapin)).
+
+
+### ClickHouse release v20.8.3.18-stable, 2020-09-18
+
+#### Bug Fix
+
+* Fix the issue when some invocations of `extractAllGroups` function may trigger "Memory limit exceeded" error. This fixes [#13383](https://github.com/ClickHouse/ClickHouse/issues/13383). [#14889](https://github.com/ClickHouse/ClickHouse/pull/14889) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix SIGSEGV for an attempt to INSERT into StorageFile(fd). [#14887](https://github.com/ClickHouse/ClickHouse/pull/14887) ([Azat Khuzhin](https://github.com/azat)).
+* Fix rare error in `SELECT` queries when the queried column has `DEFAULT` expression which depends on the other column which also has `DEFAULT` and not present in select query and not exists on disk. Partially fixes [#14531](https://github.com/ClickHouse/ClickHouse/issues/14531). [#14845](https://github.com/ClickHouse/ClickHouse/pull/14845) ([alesapin](https://github.com/alesapin)).
+* Fixed missed default database name in metadata of materialized view when executing `ALTER ... MODIFY QUERY`. [#14664](https://github.com/ClickHouse/ClickHouse/pull/14664) ([tavplubix](https://github.com/tavplubix)).
+* Fix bug when `ALTER UPDATE` mutation with Nullable column in assignment expression and constant value (like `UPDATE x = 42`) leads to incorrect value in column or segfault. Fixes [#13634](https://github.com/ClickHouse/ClickHouse/issues/13634), [#14045](https://github.com/ClickHouse/ClickHouse/issues/14045). [#14646](https://github.com/ClickHouse/ClickHouse/pull/14646) ([alesapin](https://github.com/alesapin)).
+* Fix wrong Decimal multiplication result caused wrong decimal scale of result column. [#14603](https://github.com/ClickHouse/ClickHouse/pull/14603) ([Artem Zuikov](https://github.com/4ertus2)).
+* Added the checker as neither calling `lc->isNullable()` nor calling `ls->getDictionaryPtr()->isNullable()` would return the correct result. [#14591](https://github.com/ClickHouse/ClickHouse/pull/14591) ([myrrc](https://github.com/myrrc)).
+* Cleanup data directory after Zookeeper exceptions during CreateQuery for StorageReplicatedMergeTree Engine. [#14563](https://github.com/ClickHouse/ClickHouse/pull/14563) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix rare segfaults in functions with combinator -Resample, which could appear in result of overflow with very large parameters. [#14562](https://github.com/ClickHouse/ClickHouse/pull/14562) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Improvement
+
+* Speed up server shutdown process if there are ongoing S3 requests. [#14858](https://github.com/ClickHouse/ClickHouse/pull/14858) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Allow using multi-volume storage configuration in storage Distributed. [#14839](https://github.com/ClickHouse/ClickHouse/pull/14839) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Speed up server shutdown process if there are ongoing S3 requests. [#14496](https://github.com/ClickHouse/ClickHouse/pull/14496) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Support custom codecs in compact parts. [#12183](https://github.com/ClickHouse/ClickHouse/pull/12183) ([Anton Popov](https://github.com/CurtizJ)).
+
+
+### ClickHouse release v20.8.2.3-stable, 2020-09-08
+
+#### Backward Incompatible Change
+
+* Now `OPTIMIZE FINAL` query does not recalculate TTL for parts that were added before TTL was created. Use `ALTER TABLE ... MATERIALIZE TTL` once to calculate them, after that `OPTIMIZE FINAL` will evaluate TTL's properly. This behavior never worked for replicated tables. [#14220](https://github.com/ClickHouse/ClickHouse/pull/14220) ([alesapin](https://github.com/alesapin)).
+* Extend `parallel_distributed_insert_select` setting, adding an option to run `INSERT` into local table. The setting changes type from `Bool` to `UInt64`, so the values `false` and `true` are no longer supported. If you have these values in server configuration, the server will not start. Please replace them with `0` and `1`, respectively. [#14060](https://github.com/ClickHouse/ClickHouse/pull/14060) ([Azat Khuzhin](https://github.com/azat)).
+* Remove support for the `ODBCDriver` input/output format. This was a deprecated format once used for communication with the ClickHouse ODBC driver, now long superseded by the `ODBCDriver2` format. Resolves [#13629](https://github.com/ClickHouse/ClickHouse/issues/13629). [#13847](https://github.com/ClickHouse/ClickHouse/pull/13847) ([hexiaoting](https://github.com/hexiaoting)).
+* When upgrading from versions older than 20.5, if rolling update is performed and cluster contains both versions 20.5 or greater and less than 20.5, if ClickHouse nodes with old versions are restarted and old version has been started up in presence of newer versions, it may lead to `Part ... intersects previous part` errors. To prevent this error, first install newer clickhouse-server packages on all cluster nodes and then do restarts (so, when clickhouse-server is restarted, it will start up with the new version).
+
+#### New Feature
+
+* Add the ability to specify `Default` compression codec for columns that correspond to settings specified in `config.xml`. Implements: [#9074](https://github.com/ClickHouse/ClickHouse/issues/9074). [#14049](https://github.com/ClickHouse/ClickHouse/pull/14049) ([alesapin](https://github.com/alesapin)).
+* Support Kerberos authentication in Kafka, using `krb5` and `cyrus-sasl` libraries. [#12771](https://github.com/ClickHouse/ClickHouse/pull/12771) ([Ilya Golshtein](https://github.com/ilejn)).
+* Add function `normalizeQuery` that replaces literals, sequences of literals and complex aliases with placeholders. Add function `normalizedQueryHash` that returns identical 64bit hash values for similar queries. It helps to analyze query log. This closes [#11271](https://github.com/ClickHouse/ClickHouse/issues/11271). [#13816](https://github.com/ClickHouse/ClickHouse/pull/13816) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add `time_zones` table. [#13880](https://github.com/ClickHouse/ClickHouse/pull/13880) ([Bharat Nallan](https://github.com/bharatnc)).
+* Add function `defaultValueOfTypeName` that returns the default value for a given type. [#13877](https://github.com/ClickHouse/ClickHouse/pull/13877) ([hcz](https://github.com/hczhcz)).
+* Add `countDigits(x)` function that count number of decimal digits in integer or decimal column. Add `isDecimalOverflow(d, [p])` function that checks if the value in Decimal column is out of its (or specified) precision. [#14151](https://github.com/ClickHouse/ClickHouse/pull/14151) ([Artem Zuikov](https://github.com/4ertus2)).
+* Add `quantileExactLow` and `quantileExactHigh` implementations with respective aliases for `medianExactLow` and `medianExactHigh`. [#13818](https://github.com/ClickHouse/ClickHouse/pull/13818) ([Bharat Nallan](https://github.com/bharatnc)).
+* Added `date_trunc` function that truncates a date/time value to a specified date/time part. [#13888](https://github.com/ClickHouse/ClickHouse/pull/13888) ([Vladimir Golovchenko](https://github.com/vladimir-golovchenko)).
+* Add new optional section `<user_directories>` to the main config. [#13425](https://github.com/ClickHouse/ClickHouse/pull/13425) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Add `ALTER SAMPLE BY` statement that allows to change table sample clause. [#13280](https://github.com/ClickHouse/ClickHouse/pull/13280) ([Amos Bird](https://github.com/amosbird)).
+* Function `position` now supports optional `start_pos` argument. [#13237](https://github.com/ClickHouse/ClickHouse/pull/13237) ([vdimir](https://github.com/vdimir)).
+
+#### Bug Fix
+
+* Fix visible data clobbering by progress bar in client in interactive mode. This fixes [#12562](https://github.com/ClickHouse/ClickHouse/issues/12562) and [#13369](https://github.com/ClickHouse/ClickHouse/issues/13369) and [#13584](https://github.com/ClickHouse/ClickHouse/issues/13584) and fixes [#12964](https://github.com/ClickHouse/ClickHouse/issues/12964). [#13691](https://github.com/ClickHouse/ClickHouse/pull/13691) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed incorrect sorting order if `LowCardinality` column when sorting by multiple columns. This fixes [#13958](https://github.com/ClickHouse/ClickHouse/issues/13958). [#14223](https://github.com/ClickHouse/ClickHouse/pull/14223) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Check for array size overflow in `topK` aggregate function. Without this check the user may send a query with carefully crafted parameters that will lead to server crash. This closes [#14452](https://github.com/ClickHouse/ClickHouse/issues/14452). [#14467](https://github.com/ClickHouse/ClickHouse/pull/14467) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bug which can lead to wrong merges assignment if table has partitions with a single part. [#14444](https://github.com/ClickHouse/ClickHouse/pull/14444) ([alesapin](https://github.com/alesapin)).
+* Stop query execution if exception happened in `PipelineExecutor` itself. This could prevent rare possible query hung. Continuation of [#14334](https://github.com/ClickHouse/ClickHouse/issues/14334). [#14402](https://github.com/ClickHouse/ClickHouse/pull/14402) [#14334](https://github.com/ClickHouse/ClickHouse/pull/14334) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix crash during `ALTER` query for table which was created `AS table_function`. Fixes [#14212](https://github.com/ClickHouse/ClickHouse/issues/14212). [#14326](https://github.com/ClickHouse/ClickHouse/pull/14326) ([alesapin](https://github.com/alesapin)).
+* Fix exception during ALTER LIVE VIEW query with REFRESH command. Live view is an experimental feature. [#14320](https://github.com/ClickHouse/ClickHouse/pull/14320) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix QueryPlan lifetime (for EXPLAIN PIPELINE graph=1) for queries with nested interpreter. [#14315](https://github.com/ClickHouse/ClickHouse/pull/14315) ([Azat Khuzhin](https://github.com/azat)).
+* Fix segfault in `clickhouse-odbc-bridge` during schema fetch from some external sources. This PR fixes [#13861](https://github.com/ClickHouse/ClickHouse/issues/13861). [#14267](https://github.com/ClickHouse/ClickHouse/pull/14267) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix crash in mark inclusion search introduced in [#12277](https://github.com/ClickHouse/ClickHouse/pull/12277). [#14225](https://github.com/ClickHouse/ClickHouse/pull/14225) ([Amos Bird](https://github.com/amosbird)).
+* Fix creation of tables with named tuples. This fixes [#13027](https://github.com/ClickHouse/ClickHouse/issues/13027). [#14143](https://github.com/ClickHouse/ClickHouse/pull/14143) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix formatting of minimal negative decimal numbers. This fixes [#14111](https://github.com/ClickHouse/ClickHouse/issues/14111). [#14119](https://github.com/ClickHouse/ClickHouse/pull/14119) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fix `DistributedFilesToInsert` metric (zeroed when it should not). [#14095](https://github.com/ClickHouse/ClickHouse/pull/14095) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `pointInPolygon` with const 2d array as polygon. [#14079](https://github.com/ClickHouse/ClickHouse/pull/14079) ([Alexey Ilyukhov](https://github.com/livace)).
+* Fixed wrong mount point in extra info for `Poco::Exception: no space left on device`. [#14050](https://github.com/ClickHouse/ClickHouse/pull/14050) ([tavplubix](https://github.com/tavplubix)).
+* Fix GRANT ALL statement when executed on a non-global level. [#13987](https://github.com/ClickHouse/ClickHouse/pull/13987) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix parser to reject create table as table function with engine. [#13940](https://github.com/ClickHouse/ClickHouse/pull/13940) ([hcz](https://github.com/hczhcz)).
+* Fix wrong results in select queries with `DISTINCT` keyword and subqueries with UNION ALL in case `optimize_duplicate_order_by_and_distinct` setting is enabled. [#13925](https://github.com/ClickHouse/ClickHouse/pull/13925) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixed potential deadlock when renaming `Distributed` table. [#13922](https://github.com/ClickHouse/ClickHouse/pull/13922) ([tavplubix](https://github.com/tavplubix)).
+* Fix incorrect sorting for `FixedString` columns when sorting by multiple columns. Fixes [#13182](https://github.com/ClickHouse/ClickHouse/issues/13182). [#13887](https://github.com/ClickHouse/ClickHouse/pull/13887) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix potentially imprecise result of `topK`/`topKWeighted` merge (with non-default parameters). [#13817](https://github.com/ClickHouse/ClickHouse/pull/13817) ([Azat Khuzhin](https://github.com/azat)).
+* Fix reading from MergeTree table with INDEX of type SET fails when comparing against NULL. This fixes [#13686](https://github.com/ClickHouse/ClickHouse/issues/13686). [#13793](https://github.com/ClickHouse/ClickHouse/pull/13793) ([Amos Bird](https://github.com/amosbird)).
+* Fix `arrayJoin` capturing in lambda (LOGICAL_ERROR). [#13792](https://github.com/ClickHouse/ClickHouse/pull/13792) ([Azat Khuzhin](https://github.com/azat)).
+* Add step overflow check in function `range`. [#13790](https://github.com/ClickHouse/ClickHouse/pull/13790) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed `Directory not empty` error when concurrently executing `DROP DATABASE` and `CREATE TABLE`. [#13756](https://github.com/ClickHouse/ClickHouse/pull/13756) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add range check for `h3KRing` function. This fixes [#13633](https://github.com/ClickHouse/ClickHouse/issues/13633). [#13752](https://github.com/ClickHouse/ClickHouse/pull/13752) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix race condition between DETACH and background merges. Parts may revive after detach. This is continuation of [#8602](https://github.com/ClickHouse/ClickHouse/issues/8602) that did not fix the issue but introduced a test that started to fail in very rare cases, demonstrating the issue. [#13746](https://github.com/ClickHouse/ClickHouse/pull/13746) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix logging Settings.Names/Values when log_queries_min_type > QUERY_START. [#13737](https://github.com/ClickHouse/ClickHouse/pull/13737) ([Azat Khuzhin](https://github.com/azat)).
+* Fixes `/replicas_status` endpoint response status code when verbose=1. [#13722](https://github.com/ClickHouse/ClickHouse/pull/13722) ([javi santana](https://github.com/javisantana)).
+* Fix incorrect message in `clickhouse-server.init` while checking user and group. [#13711](https://github.com/ClickHouse/ClickHouse/pull/13711) ([ylchou](https://github.com/ylchou)).
+* Do not optimize any(arrayJoin()) -> arrayJoin() under `optimize_move_functions_out_of_any` setting. [#13681](https://github.com/ClickHouse/ClickHouse/pull/13681) ([Azat Khuzhin](https://github.com/azat)).
+* Fix crash in JOIN with StorageMerge and `set enable_optimize_predicate_expression=1`. [#13679](https://github.com/ClickHouse/ClickHouse/pull/13679) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix typo in error message about `The value of 'number_of_free_entries_in_pool_to_lower_max_size_of_merge' setting`. [#13678](https://github.com/ClickHouse/ClickHouse/pull/13678) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Concurrent `ALTER ... REPLACE/MOVE PARTITION ...` queries might cause deadlock. It's fixed. [#13626](https://github.com/ClickHouse/ClickHouse/pull/13626) ([tavplubix](https://github.com/tavplubix)).
+* Fixed the behaviour when sometimes cache-dictionary returned default value instead of present value from source. [#13624](https://github.com/ClickHouse/ClickHouse/pull/13624) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix secondary indices corruption in compact parts. Compact parts are experimental feature. [#13538](https://github.com/ClickHouse/ClickHouse/pull/13538) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix premature `ON CLUSTER` timeouts for queries that must be executed on a single replica. Fixes [#6704](https://github.com/ClickHouse/ClickHouse/issues/6704), [#7228](https://github.com/ClickHouse/ClickHouse/issues/7228), [#13361](https://github.com/ClickHouse/ClickHouse/issues/13361), [#11884](https://github.com/ClickHouse/ClickHouse/issues/11884). [#13450](https://github.com/ClickHouse/ClickHouse/pull/13450) ([alesapin](https://github.com/alesapin)).
+* Fix wrong code in function `netloc`. This fixes [#13335](https://github.com/ClickHouse/ClickHouse/issues/13335). [#13446](https://github.com/ClickHouse/ClickHouse/pull/13446) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible race in `StorageMemory`. [#13416](https://github.com/ClickHouse/ClickHouse/pull/13416) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix missing or excessive headers in `TSV/CSVWithNames` formats in HTTP protocol. This fixes [#12504](https://github.com/ClickHouse/ClickHouse/issues/12504). [#13343](https://github.com/ClickHouse/ClickHouse/pull/13343) ([Azat Khuzhin](https://github.com/azat)).
+* Fix parsing row policies from users.xml when names of databases or tables contain dots. This fixes [#5779](https://github.com/ClickHouse/ClickHouse/issues/5779), [#12527](https://github.com/ClickHouse/ClickHouse/issues/12527). [#13199](https://github.com/ClickHouse/ClickHouse/pull/13199) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix access to `redis` dictionary after connection was dropped once. It may happen with `cache` and `direct` dictionary layouts. [#13082](https://github.com/ClickHouse/ClickHouse/pull/13082) ([Anton Popov](https://github.com/CurtizJ)).
+* Removed wrong auth access check when using ClickHouseDictionarySource to query remote tables. [#12756](https://github.com/ClickHouse/ClickHouse/pull/12756) ([sundyli](https://github.com/sundy-li)).
+* Properly distinguish subqueries in some cases for common subexpression elimination. [#8333](https://github.com/ClickHouse/ClickHouse/issues/8333). [#8367](https://github.com/ClickHouse/ClickHouse/pull/8367) ([Amos Bird](https://github.com/amosbird)).
+
+#### Improvement
+
+* Disallows `CODEC` on `ALIAS` column type. Fixes [#13911](https://github.com/ClickHouse/ClickHouse/issues/13911). [#14263](https://github.com/ClickHouse/ClickHouse/pull/14263) ([Bharat Nallan](https://github.com/bharatnc)).
+* When waiting for a dictionary update to complete, use the timeout specified by `query_wait_timeout_milliseconds` setting instead of a hard-coded value. [#14105](https://github.com/ClickHouse/ClickHouse/pull/14105) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Add setting `min_index_granularity_bytes` that protects against accidentally creating a table with very low `index_granularity_bytes` setting. [#14139](https://github.com/ClickHouse/ClickHouse/pull/14139) ([Bharat Nallan](https://github.com/bharatnc)).
+* Now it's possible to fetch partitions from clusters that use different ZooKeeper: `ALTER TABLE table_name FETCH PARTITION partition_expr FROM 'zk-name:/path-in-zookeeper'`. It's useful for shipping data to new clusters. [#14155](https://github.com/ClickHouse/ClickHouse/pull/14155) ([Amos Bird](https://github.com/amosbird)).
+* Slightly better performance of Memory table if it was constructed from a huge number of very small blocks (that's unlikely). Author of the idea: [Mark Papadakis](https://github.com/markpapadakis). Closes [#14043](https://github.com/ClickHouse/ClickHouse/issues/14043). [#14056](https://github.com/ClickHouse/ClickHouse/pull/14056) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Conditional aggregate functions (for example: `avgIf`, `sumIf`, `maxIf`) should return `NULL` when miss rows and use nullable arguments. [#13964](https://github.com/ClickHouse/ClickHouse/pull/13964) ([Winter Zhang](https://github.com/zhang2014)).
+* Increase limit in -Resample combinator to 1M. [#13947](https://github.com/ClickHouse/ClickHouse/pull/13947) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
+* Corrected an error in AvroConfluent format that caused the Kafka table engine to stop processing messages when an abnormally small, malformed, message was received. [#13941](https://github.com/ClickHouse/ClickHouse/pull/13941) ([Gervasio Varela](https://github.com/gervarela)).
+* Fix wrong error for long queries. It was possible to get syntax error other than `Max query size exceeded` for correct query. [#13928](https://github.com/ClickHouse/ClickHouse/pull/13928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Better error message for null value of `TabSeparated` format. [#13906](https://github.com/ClickHouse/ClickHouse/pull/13906) ([jiang tao](https://github.com/tomjiang1987)).
+* Function `arrayCompact` will compare NaNs bitwise if the type of array elements is Float32/Float64. In previous versions NaNs were always not equal if the type of array elements is Float32/Float64 and were always equal if the type is more complex, like Nullable(Float64). This closes [#13857](https://github.com/ClickHouse/ClickHouse/issues/13857). [#13868](https://github.com/ClickHouse/ClickHouse/pull/13868) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix data race in `lgamma` function. This race was caught only in `tsan`, no side effects a really happened. [#13842](https://github.com/ClickHouse/ClickHouse/pull/13842) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Avoid too slow queries when arrays are manipulated as fields. Throw exception instead. [#13753](https://github.com/ClickHouse/ClickHouse/pull/13753) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added Redis requirepass authorization (for redis dictionary source). [#13688](https://github.com/ClickHouse/ClickHouse/pull/13688) ([Ivan Torgashov](https://github.com/it1804)).
+* Add MergeTree Write-Ahead-Log (WAL) dump tool. WAL is an experimental feature. [#13640](https://github.com/ClickHouse/ClickHouse/pull/13640) ([BohuTANG](https://github.com/BohuTANG)).
+* In previous versions `lcm` function may produce assertion violation in debug build if called with specifically crafted arguments. This fixes [#13368](https://github.com/ClickHouse/ClickHouse/issues/13368). [#13510](https://github.com/ClickHouse/ClickHouse/pull/13510) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Provide monotonicity for `toDate/toDateTime` functions in more cases. Monotonicity information is used for index analysis (more complex queries will be able to use index). Now the input arguments are saturated more naturally and provides better monotonicity. [#13497](https://github.com/ClickHouse/ClickHouse/pull/13497) ([Amos Bird](https://github.com/amosbird)).
+* Support compound identifiers for custom settings. Custom settings is an integration point of ClickHouse codebase with other codebases (no benefits for ClickHouse itself) [#13496](https://github.com/ClickHouse/ClickHouse/pull/13496) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Move parts from DiskLocal to DiskS3 in parallel. `DiskS3` is an experimental feature. [#13459](https://github.com/ClickHouse/ClickHouse/pull/13459) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Enable mixed granularity parts by default. [#13449](https://github.com/ClickHouse/ClickHouse/pull/13449) ([alesapin](https://github.com/alesapin)).
+* Proper remote host checking in S3 redirects (security-related thing). [#13404](https://github.com/ClickHouse/ClickHouse/pull/13404) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Add `QueryTimeMicroseconds`, `SelectQueryTimeMicroseconds` and `InsertQueryTimeMicroseconds` to system.events. [#13336](https://github.com/ClickHouse/ClickHouse/pull/13336) ([ianton-ru](https://github.com/ianton-ru)).
+* Fix debug assertion when Decimal has too large negative exponent. Fixes [#13188](https://github.com/ClickHouse/ClickHouse/issues/13188). [#13228](https://github.com/ClickHouse/ClickHouse/pull/13228) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added cache layer for DiskS3 (cache to local disk mark and index files). `DiskS3` is an experimental feature. [#13076](https://github.com/ClickHouse/ClickHouse/pull/13076) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fix readline so it dumps history to file now. [#13600](https://github.com/ClickHouse/ClickHouse/pull/13600) ([Amos Bird](https://github.com/amosbird)).
+* Create `system` database with `Atomic` engine by default (a preparation to enable `Atomic` database engine by default everywhere). [#13680](https://github.com/ClickHouse/ClickHouse/pull/13680) ([tavplubix](https://github.com/tavplubix)).
+
+#### Performance Improvement
+
+* Slightly optimize very short queries with `LowCardinality`. [#14129](https://github.com/ClickHouse/ClickHouse/pull/14129) ([Anton Popov](https://github.com/CurtizJ)).
+* Enable parallel INSERTs for table engines `Null`, `Memory`, `Distributed` and `Buffer` when the setting `max_insert_threads` is set. [#14120](https://github.com/ClickHouse/ClickHouse/pull/14120) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fail fast if `max_rows_to_read` limit is exceeded on parts scan. The motivation behind this change is to skip ranges scan for all selected parts if it is clear that `max_rows_to_read` is already exceeded. The change is quite noticeable for queries over big number of parts. [#13677](https://github.com/ClickHouse/ClickHouse/pull/13677) ([Roman Khavronenko](https://github.com/hagen1778)).
+* Slightly improve performance of aggregation by UInt8/UInt16 keys. [#13099](https://github.com/ClickHouse/ClickHouse/pull/13099) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Optimize `has()`, `indexOf()` and `countEqual()` functions for `Array(LowCardinality(T))` and constant right arguments. [#12550](https://github.com/ClickHouse/ClickHouse/pull/12550) ([myrrc](https://github.com/myrrc)).
+* When performing trivial `INSERT SELECT` queries, automatically set `max_threads` to 1 or `max_insert_threads`, and set `max_block_size` to `min_insert_block_size_rows`. Related to [#5907](https://github.com/ClickHouse/ClickHouse/issues/5907). [#12195](https://github.com/ClickHouse/ClickHouse/pull/12195) ([flynn](https://github.com/ucasFL)).
+
+#### Experimental Feature
+
+* ClickHouse can work as MySQL replica - it is implemented by `MaterializeMySQL` database engine. Implements [#4006](https://github.com/ClickHouse/ClickHouse/issues/4006). [#10851](https://github.com/ClickHouse/ClickHouse/pull/10851) ([Winter Zhang](https://github.com/zhang2014)).
+* Add types `Int128`, `Int256`, `UInt256` and related functions for them. Extend Decimals with Decimal256 (precision up to 76 digits). New types are under the setting `allow_experimental_bigint_types`. It is working extremely slow and bad. The implementation is incomplete. Please don't use this feature. [#13097](https://github.com/ClickHouse/ClickHouse/pull/13097) ([Artem Zuikov](https://github.com/4ertus2)).
+
+#### Build/Testing/Packaging Improvement
+
+* Added `clickhouse install` script, that is useful if you only have a single binary. [#13528](https://github.com/ClickHouse/ClickHouse/pull/13528) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow to run `clickhouse` binary without configuration. [#13515](https://github.com/ClickHouse/ClickHouse/pull/13515) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Enable check for typos in code with `codespell`. [#13513](https://github.com/ClickHouse/ClickHouse/pull/13513) [#13511](https://github.com/ClickHouse/ClickHouse/pull/13511) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Enable Shellcheck in CI as a linter of .sh tests. This closes [#13168](https://github.com/ClickHouse/ClickHouse/issues/13168). [#13530](https://github.com/ClickHouse/ClickHouse/pull/13530) [#13529](https://github.com/ClickHouse/ClickHouse/pull/13529) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add a CMake option to fail configuration instead of auto-reconfiguration, enabled by default. [#13687](https://github.com/ClickHouse/ClickHouse/pull/13687) ([Konstantin](https://github.com/podshumok)).
+* Expose version of embedded tzdata via TZDATA_VERSION in system.build_options. [#13648](https://github.com/ClickHouse/ClickHouse/pull/13648) ([filimonov](https://github.com/filimonov)).
+* Improve generation of system.time_zones table during build. Closes [#14209](https://github.com/ClickHouse/ClickHouse/issues/14209). [#14215](https://github.com/ClickHouse/ClickHouse/pull/14215) ([filimonov](https://github.com/filimonov)).
+* Build ClickHouse with the most fresh tzdata from package repository. [#13623](https://github.com/ClickHouse/ClickHouse/pull/13623) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add the ability to write js-style comments in skip_list.json. [#14159](https://github.com/ClickHouse/ClickHouse/pull/14159) ([alesapin](https://github.com/alesapin)).
+* Ensure that there is no copy-pasted GPL code. [#13514](https://github.com/ClickHouse/ClickHouse/pull/13514) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Switch tests docker images to use test-base parent. [#14167](https://github.com/ClickHouse/ClickHouse/pull/14167) ([Ilya Yatsishin](https://github.com/qoega)).
+* Adding retry logic when bringing up docker-compose cluster; Increasing COMPOSE_HTTP_TIMEOUT. [#14112](https://github.com/ClickHouse/ClickHouse/pull/14112) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Enabled `system.text_log` in stress test to find more bugs. [#13855](https://github.com/ClickHouse/ClickHouse/pull/13855) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Testflows LDAP module: adding missing certificates and dhparam.pem for openldap4. [#13780](https://github.com/ClickHouse/ClickHouse/pull/13780) ([vzakaznikov](https://github.com/vzakaznikov)).
+* ZooKeeper cannot work reliably in unit tests in CI infrastructure. Using unit tests for ZooKeeper interaction with real ZooKeeper is bad idea from the start (unit tests are not supposed to verify complex distributed systems). We already using integration tests for this purpose and they are better suited. [#13745](https://github.com/ClickHouse/ClickHouse/pull/13745) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added docker image for style check. Added style check that all docker and docker compose files are located in docker directory. [#13724](https://github.com/ClickHouse/ClickHouse/pull/13724) ([Ilya Yatsishin](https://github.com/qoega)).
+* Fix cassandra build on Mac OS. [#13708](https://github.com/ClickHouse/ClickHouse/pull/13708) ([Ilya Yatsishin](https://github.com/qoega)).
+* Fix link error in shared build. [#13700](https://github.com/ClickHouse/ClickHouse/pull/13700) ([Amos Bird](https://github.com/amosbird)).
+* Updating LDAP user authentication suite to check that it works with RBAC. [#13656](https://github.com/ClickHouse/ClickHouse/pull/13656) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Removed `-DENABLE_CURL_CLIENT` for `contrib/aws`. [#13628](https://github.com/ClickHouse/ClickHouse/pull/13628) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Increasing health-check timeouts for ClickHouse nodes and adding support to dump docker-compose logs if unhealthy containers found. [#13612](https://github.com/ClickHouse/ClickHouse/pull/13612) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Make sure [#10977](https://github.com/ClickHouse/ClickHouse/issues/10977) is invalid. [#13539](https://github.com/ClickHouse/ClickHouse/pull/13539) ([Amos Bird](https://github.com/amosbird)).
+* Skip PR's from robot-clickhouse. [#13489](https://github.com/ClickHouse/ClickHouse/pull/13489) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Move Dockerfiles from integration tests to `docker/test` directory. docker_compose files are available in `runner` docker container. Docker images are built in CI and not in integration tests. [#13448](https://github.com/ClickHouse/ClickHouse/pull/13448) ([Ilya Yatsishin](https://github.com/qoega)).
+
+
+## ClickHouse release 20.7
+
+### ClickHouse release v20.7.2.30-stable, 2020-08-31
+
+#### Backward Incompatible Change
+
+* Function `modulo` (operator `%`) with at least one floating point number as argument will calculate remainder of division directly on floating point numbers without converting both arguments to integers. It makes behaviour compatible with most of DBMS. This also applicable for Date and DateTime data types. Added alias `mod`. This closes [#7323](https://github.com/ClickHouse/ClickHouse/issues/7323). [#12585](https://github.com/ClickHouse/ClickHouse/pull/12585) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Deprecate special printing of zero Date/DateTime values as `0000-00-00` and `0000-00-00 00:00:00`. [#12442](https://github.com/ClickHouse/ClickHouse/pull/12442) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* The function `groupArrayMoving*` was not working for distributed queries. It's result was calculated within incorrect data type (without promotion to the largest type). The function `groupArrayMovingAvg` was returning integer number that was inconsistent with the `avg` function. This fixes [#12568](https://github.com/ClickHouse/ClickHouse/issues/12568). [#12622](https://github.com/ClickHouse/ClickHouse/pull/12622) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add sanity check for MergeTree settings. If the settings are incorrect, the server will refuse to start or to create a table, printing detailed explanation to the user. [#13153](https://github.com/ClickHouse/ClickHouse/pull/13153) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Protect from the cases when user may set `background_pool_size` to value lower than `number_of_free_entries_in_pool_to_execute_mutation` or `number_of_free_entries_in_pool_to_lower_max_size_of_merge`. In these cases ALTERs won't work or the maximum size of merge will be too limited. It will throw exception explaining what to do. This closes [#10897](https://github.com/ClickHouse/ClickHouse/issues/10897). [#12728](https://github.com/ClickHouse/ClickHouse/pull/12728) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* When upgrading from versions older than 20.5, if rolling update is performed and cluster contains both versions 20.5 or greater and less than 20.5, if ClickHouse nodes with old versions are restarted and old version has been started up in presence of newer versions, it may lead to `Part ... intersects previous part` errors. To prevent this error, first install newer clickhouse-server packages on all cluster nodes and then do restarts (so, when clickhouse-server is restarted, it will start up with the new version).
+
+#### New Feature
+
+* Polygon dictionary type that provides efficient "reverse geocoding" lookups - to find the region by coordinates in a dictionary of many polygons (world map). It is using carefully optimized algorithm with recursive grids to maintain low CPU and memory usage. [#9278](https://github.com/ClickHouse/ClickHouse/pull/9278) ([achulkov2](https://github.com/achulkov2)).
+* Added support of LDAP authentication for preconfigured users ("Simple Bind" method). [#11234](https://github.com/ClickHouse/ClickHouse/pull/11234) ([Denis Glazachev](https://github.com/traceon)).
+* Introduce setting `alter_partition_verbose_result` which outputs information about touched parts for some types of `ALTER TABLE ... PARTITION ...` queries (currently `ATTACH` and `FREEZE`). Closes [#8076](https://github.com/ClickHouse/ClickHouse/issues/8076). [#13017](https://github.com/ClickHouse/ClickHouse/pull/13017) ([alesapin](https://github.com/alesapin)).
+* Add `bayesAB` function for bayesian-ab-testing. [#12327](https://github.com/ClickHouse/ClickHouse/pull/12327) ([achimbab](https://github.com/achimbab)).
+* Added `system.crash_log` table into which stack traces for fatal errors are collected. This table should be empty. [#12316](https://github.com/ClickHouse/ClickHouse/pull/12316) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added http headers `X-ClickHouse-Database` and `X-ClickHouse-Format` which may be used to set default database and output format. [#12981](https://github.com/ClickHouse/ClickHouse/pull/12981) ([hcz](https://github.com/hczhcz)).
+* Add `minMap` and `maxMap` functions support to `SimpleAggregateFunction`. [#12662](https://github.com/ClickHouse/ClickHouse/pull/12662) ([Ildus Kurbangaliev](https://github.com/ildus)).
+* Add setting `allow_non_metadata_alters` which restricts to execute `ALTER` queries which modify data on disk. Disabled be default. Closes [#11547](https://github.com/ClickHouse/ClickHouse/issues/11547). [#12635](https://github.com/ClickHouse/ClickHouse/pull/12635) ([alesapin](https://github.com/alesapin)).
+* A function `formatRow` is added to support turning arbitrary expressions into a string via given format. It's useful for manipulating SQL outputs and is quite versatile combined with the `columns` function. [#12574](https://github.com/ClickHouse/ClickHouse/pull/12574) ([Amos Bird](https://github.com/amosbird)).
+* Add `FROM_UNIXTIME` function for compatibility with MySQL, related to [12149](https://github.com/ClickHouse/ClickHouse/issues/12149). [#12484](https://github.com/ClickHouse/ClickHouse/pull/12484) ([flynn](https://github.com/ucasFL)).
+* Allow Nullable types as keys in MergeTree tables if `allow_nullable_key` table setting is enabled. Closes [#5319](https://github.com/ClickHouse/ClickHouse/issues/5319). [#12433](https://github.com/ClickHouse/ClickHouse/pull/12433) ([Amos Bird](https://github.com/amosbird)).
+* Integration with [COS](https://intl.cloud.tencent.com/product/cos). [#12386](https://github.com/ClickHouse/ClickHouse/pull/12386) ([fastio](https://github.com/fastio)).
+* Add `mapAdd` and `mapSubtract` functions for adding/subtracting key-mapped values. [#11735](https://github.com/ClickHouse/ClickHouse/pull/11735) ([Ildus Kurbangaliev](https://github.com/ildus)).
+
+#### Bug Fix
+
+* Fix premature `ON CLUSTER` timeouts for queries that must be executed on a single replica. Fixes [#6704](https://github.com/ClickHouse/ClickHouse/issues/6704), [#7228](https://github.com/ClickHouse/ClickHouse/issues/7228), [#13361](https://github.com/ClickHouse/ClickHouse/issues/13361), [#11884](https://github.com/ClickHouse/ClickHouse/issues/11884). [#13450](https://github.com/ClickHouse/ClickHouse/pull/13450) ([alesapin](https://github.com/alesapin)).
+* Fix crash in mark inclusion search introduced in [#12277](https://github.com/ClickHouse/ClickHouse/pull/12277). [#14225](https://github.com/ClickHouse/ClickHouse/pull/14225) ([Amos Bird](https://github.com/amosbird)).
+* Fix race condition in external dictionaries with cache layout which can lead server crash. [#12566](https://github.com/ClickHouse/ClickHouse/pull/12566) ([alesapin](https://github.com/alesapin)).
+* Fix visible data clobbering by progress bar in client in interactive mode. This fixes [#12562](https://github.com/ClickHouse/ClickHouse/issues/12562) and [#13369](https://github.com/ClickHouse/ClickHouse/issues/13369) and [#13584](https://github.com/ClickHouse/ClickHouse/issues/13584) and fixes [#12964](https://github.com/ClickHouse/ClickHouse/issues/12964). [#13691](https://github.com/ClickHouse/ClickHouse/pull/13691) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed incorrect sorting order for `LowCardinality` columns when ORDER BY multiple columns is used. This fixes [#13958](https://github.com/ClickHouse/ClickHouse/issues/13958). [#14223](https://github.com/ClickHouse/ClickHouse/pull/14223) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Removed hardcoded timeout, which wrongly overruled `query_wait_timeout_milliseconds` setting for cache-dictionary. [#14105](https://github.com/ClickHouse/ClickHouse/pull/14105) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed wrong mount point in extra info for `Poco::Exception: no space left on device`. [#14050](https://github.com/ClickHouse/ClickHouse/pull/14050) ([tavplubix](https://github.com/tavplubix)).
+* Fix wrong query optimization of select queries with `DISTINCT` keyword when subqueries also have `DISTINCT` in case `optimize_duplicate_order_by_and_distinct` setting is enabled. [#13925](https://github.com/ClickHouse/ClickHouse/pull/13925) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixed potential deadlock when renaming `Distributed` table. [#13922](https://github.com/ClickHouse/ClickHouse/pull/13922) ([tavplubix](https://github.com/tavplubix)).
+* Fix incorrect sorting for `FixedString` columns when ORDER BY multiple columns is used. Fixes [#13182](https://github.com/ClickHouse/ClickHouse/issues/13182). [#13887](https://github.com/ClickHouse/ClickHouse/pull/13887) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix potentially lower precision of `topK`/`topKWeighted` aggregations (with non-default parameters). [#13817](https://github.com/ClickHouse/ClickHouse/pull/13817) ([Azat Khuzhin](https://github.com/azat)).
+* Fix reading from MergeTree table with INDEX of type SET fails when compared against NULL. This fixes [#13686](https://github.com/ClickHouse/ClickHouse/issues/13686). [#13793](https://github.com/ClickHouse/ClickHouse/pull/13793) ([Amos Bird](https://github.com/amosbird)).
+* Fix step overflow in function `range()`. [#13790](https://github.com/ClickHouse/ClickHouse/pull/13790) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed `Directory not empty` error when concurrently executing `DROP DATABASE` and `CREATE TABLE`. [#13756](https://github.com/ClickHouse/ClickHouse/pull/13756) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add range check for `h3KRing` function. This fixes [#13633](https://github.com/ClickHouse/ClickHouse/issues/13633). [#13752](https://github.com/ClickHouse/ClickHouse/pull/13752) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix race condition between DETACH and background merges. Parts may revive after detach. This is continuation of [#8602](https://github.com/ClickHouse/ClickHouse/issues/8602) that did not fix the issue but introduced a test that started to fail in very rare cases, demonstrating the issue. [#13746](https://github.com/ClickHouse/ClickHouse/pull/13746) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix logging Settings.Names/Values when `log_queries_min_type` greater than `QUERY_START`. [#13737](https://github.com/ClickHouse/ClickHouse/pull/13737) ([Azat Khuzhin](https://github.com/azat)).
+* Fix incorrect message in `clickhouse-server.init` while checking user and group. [#13711](https://github.com/ClickHouse/ClickHouse/pull/13711) ([ylchou](https://github.com/ylchou)).
+* Do not optimize `any(arrayJoin())` to `arrayJoin()` under `optimize_move_functions_out_of_any`. [#13681](https://github.com/ClickHouse/ClickHouse/pull/13681) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed possible deadlock in concurrent `ALTER ... REPLACE/MOVE PARTITION ...` queries. [#13626](https://github.com/ClickHouse/ClickHouse/pull/13626) ([tavplubix](https://github.com/tavplubix)).
+* Fixed the behaviour when sometimes cache-dictionary returned default value instead of present value from source. [#13624](https://github.com/ClickHouse/ClickHouse/pull/13624) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix secondary indices corruption in compact parts (compact parts is an experimental feature). [#13538](https://github.com/ClickHouse/ClickHouse/pull/13538) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix wrong code in function `netloc`. This fixes [#13335](https://github.com/ClickHouse/ClickHouse/issues/13335). [#13446](https://github.com/ClickHouse/ClickHouse/pull/13446) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix error in `parseDateTimeBestEffort` function when unix timestamp was passed as an argument. This fixes [#13362](https://github.com/ClickHouse/ClickHouse/issues/13362). [#13441](https://github.com/ClickHouse/ClickHouse/pull/13441) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix invalid return type for comparison of tuples with `NULL` elements. Fixes [#12461](https://github.com/ClickHouse/ClickHouse/issues/12461). [#13420](https://github.com/ClickHouse/ClickHouse/pull/13420) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix wrong optimization caused `aggregate function any(x) is found inside another aggregate function in query` error with `SET optimize_move_functions_out_of_any = 1` and aliases inside `any()`. [#13419](https://github.com/ClickHouse/ClickHouse/pull/13419) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix possible race in `StorageMemory`. [#13416](https://github.com/ClickHouse/ClickHouse/pull/13416) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix empty output for `Arrow` and `Parquet` formats in case if query return zero rows. It was done because empty output is not valid for this formats. [#13399](https://github.com/ClickHouse/ClickHouse/pull/13399) ([hcz](https://github.com/hczhcz)).
+* Fix select queries with constant columns and prefix of primary key in `ORDER BY` clause. [#13396](https://github.com/ClickHouse/ClickHouse/pull/13396) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix `PrettyCompactMonoBlock` for clickhouse-local. Fix extremes/totals with `PrettyCompactMonoBlock`. Fixes [#7746](https://github.com/ClickHouse/ClickHouse/issues/7746). [#13394](https://github.com/ClickHouse/ClickHouse/pull/13394) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed deadlock in system.text_log. [#12452](https://github.com/ClickHouse/ClickHouse/pull/12452) ([alexey-milovidov](https://github.com/alexey-milovidov)). It is a part of [#12339](https://github.com/ClickHouse/ClickHouse/issues/12339). This fixes [#12325](https://github.com/ClickHouse/ClickHouse/issues/12325). [#13386](https://github.com/ClickHouse/ClickHouse/pull/13386) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed `File(TSVWithNames*)` (header was written multiple times), fixed `clickhouse-local --format CSVWithNames*` (lacks header, broken after [#12197](https://github.com/ClickHouse/ClickHouse/issues/12197)), fixed `clickhouse-local --format CSVWithNames*` with zero rows (lacks header). [#13343](https://github.com/ClickHouse/ClickHouse/pull/13343) ([Azat Khuzhin](https://github.com/azat)).
+* Fix segfault when function `groupArrayMovingSum` deserializes empty state. Fixes [#13339](https://github.com/ClickHouse/ClickHouse/issues/13339). [#13341](https://github.com/ClickHouse/ClickHouse/pull/13341) ([alesapin](https://github.com/alesapin)).
+* Throw error on `arrayJoin()` function in `JOIN ON` section. [#13330](https://github.com/ClickHouse/ClickHouse/pull/13330) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix crash in `LEFT ASOF JOIN` with `join_use_nulls=1`. [#13291](https://github.com/ClickHouse/ClickHouse/pull/13291) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix possible error `Totals having transform was already added to pipeline` in case of a query from delayed replica. [#13290](https://github.com/ClickHouse/ClickHouse/pull/13290) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* The server may crash if user passed specifically crafted arguments to the function `h3ToChildren`. This fixes [#13275](https://github.com/ClickHouse/ClickHouse/issues/13275). [#13277](https://github.com/ClickHouse/ClickHouse/pull/13277) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix potentially low performance and slightly incorrect result for `uniqExact`, `topK`, `sumDistinct` and similar aggregate functions called on Float types with `NaN` values. It also triggered assert in debug build. This fixes [#12491](https://github.com/ClickHouse/ClickHouse/issues/12491). [#13254](https://github.com/ClickHouse/ClickHouse/pull/13254) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix assertion in KeyCondition when primary key contains expression with monotonic function and query contains comparison with constant whose type is different. This fixes [#12465](https://github.com/ClickHouse/ClickHouse/issues/12465). [#13251](https://github.com/ClickHouse/ClickHouse/pull/13251) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Return passed number for numbers with MSB set in function roundUpToPowerOfTwoOrZero(). It prevents potential errors in case of overflow of array sizes. [#13234](https://github.com/ClickHouse/ClickHouse/pull/13234) ([Azat Khuzhin](https://github.com/azat)).
+* Fix function if with nullable constexpr as cond that is not literal NULL. Fixes [#12463](https://github.com/ClickHouse/ClickHouse/issues/12463). [#13226](https://github.com/ClickHouse/ClickHouse/pull/13226) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix assert in `arrayElement` function in case of array elements are Nullable and array subscript is also Nullable. This fixes [#12172](https://github.com/ClickHouse/ClickHouse/issues/12172). [#13224](https://github.com/ClickHouse/ClickHouse/pull/13224) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix DateTime64 conversion functions with constant argument. [#13205](https://github.com/ClickHouse/ClickHouse/pull/13205) ([Azat Khuzhin](https://github.com/azat)).
+* Fix parsing row policies from users.xml when names of databases or tables contain dots. This fixes [#5779](https://github.com/ClickHouse/ClickHouse/issues/5779), [#12527](https://github.com/ClickHouse/ClickHouse/issues/12527). [#13199](https://github.com/ClickHouse/ClickHouse/pull/13199) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix access to `redis` dictionary after connection was dropped once. It may happen with `cache` and `direct` dictionary layouts. [#13082](https://github.com/ClickHouse/ClickHouse/pull/13082) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix wrong index analysis with functions. It could lead to some data parts being skipped when reading from `MergeTree` tables. Fixes [#13060](https://github.com/ClickHouse/ClickHouse/issues/13060). Fixes [#12406](https://github.com/ClickHouse/ClickHouse/issues/12406). [#13081](https://github.com/ClickHouse/ClickHouse/pull/13081) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix error `Cannot convert column because it is constant but values of constants are different in source and result` for remote queries which use deterministic functions in scope of query, but not deterministic between queries, like `now()`, `now64()`, `randConstant()`. Fixes [#11327](https://github.com/ClickHouse/ClickHouse/issues/11327). [#13075](https://github.com/ClickHouse/ClickHouse/pull/13075) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix crash which was possible for queries with `ORDER BY` tuple and small `LIMIT`. Fixes [#12623](https://github.com/ClickHouse/ClickHouse/issues/12623). [#13009](https://github.com/ClickHouse/ClickHouse/pull/13009) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix `Block structure mismatch` error for queries with `UNION` and `JOIN`. Fixes [#12602](https://github.com/ClickHouse/ClickHouse/issues/12602). [#12989](https://github.com/ClickHouse/ClickHouse/pull/12989) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Corrected `merge_with_ttl_timeout` logic which did not work well when expiration affected more than one partition over one time interval. (Authored by @excitoon). [#12982](https://github.com/ClickHouse/ClickHouse/pull/12982) ([Alexander Kazakov](https://github.com/Akazz)).
+* Fix columns duplication for range hashed dictionary created from DDL query. This fixes [#10605](https://github.com/ClickHouse/ClickHouse/issues/10605). [#12857](https://github.com/ClickHouse/ClickHouse/pull/12857) ([alesapin](https://github.com/alesapin)).
+* Fix unnecessary limiting for the number of threads for selects from local replica. [#12840](https://github.com/ClickHouse/ClickHouse/pull/12840) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix rare bug when `ALTER DELETE` and `ALTER MODIFY COLUMN` queries executed simultaneously as a single mutation. Bug leads to an incorrect amount of rows in `count.txt` and as a consequence incorrect data in part. Also, fix a small bug with simultaneous `ALTER RENAME COLUMN` and `ALTER ADD COLUMN`. [#12760](https://github.com/ClickHouse/ClickHouse/pull/12760) ([alesapin](https://github.com/alesapin)).
+* Wrong credentials being used when using `clickhouse` dictionary source to query remote tables. [#12756](https://github.com/ClickHouse/ClickHouse/pull/12756) ([sundyli](https://github.com/sundy-li)).
+* Fix `CAST(Nullable(String), Enum())`. [#12745](https://github.com/ClickHouse/ClickHouse/pull/12745) ([Azat Khuzhin](https://github.com/azat)).
+* Fix performance with large tuples, which are interpreted as functions in `IN` section. The case when user writes `WHERE x IN tuple(1, 2, ...)` instead of `WHERE x IN (1, 2, ...)` for some obscure reason. [#12700](https://github.com/ClickHouse/ClickHouse/pull/12700) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix memory tracking for input_format_parallel_parsing (by attaching thread to group). [#12672](https://github.com/ClickHouse/ClickHouse/pull/12672) ([Azat Khuzhin](https://github.com/azat)).
+* Fix wrong optimization `optimize_move_functions_out_of_any=1` in case of `any(func(<lambda>))`. [#12664](https://github.com/ClickHouse/ClickHouse/pull/12664) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixed [#10572](https://github.com/ClickHouse/ClickHouse/issues/10572) fix bloom filter index with const expression. [#12659](https://github.com/ClickHouse/ClickHouse/pull/12659) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix SIGSEGV in StorageKafka when broker is unavailable (and not only). [#12658](https://github.com/ClickHouse/ClickHouse/pull/12658) ([Azat Khuzhin](https://github.com/azat)).
+* Add support for function `if` with `Array(UUID)` arguments. This fixes [#11066](https://github.com/ClickHouse/ClickHouse/issues/11066). [#12648](https://github.com/ClickHouse/ClickHouse/pull/12648) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* CREATE USER IF NOT EXISTS now does not throw exception if the user exists. This fixes [#12507](https://github.com/ClickHouse/ClickHouse/issues/12507). [#12646](https://github.com/ClickHouse/ClickHouse/pull/12646) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Exception `There is no supertype...` can be thrown during `ALTER ... UPDATE` in unexpected cases (e.g. when subtracting from UInt64 column). This fixes [#7306](https://github.com/ClickHouse/ClickHouse/issues/7306). This fixes [#4165](https://github.com/ClickHouse/ClickHouse/issues/4165). [#12633](https://github.com/ClickHouse/ClickHouse/pull/12633) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible `Pipeline stuck` error for queries with external sorting. Fixes [#12617](https://github.com/ClickHouse/ClickHouse/issues/12617). [#12618](https://github.com/ClickHouse/ClickHouse/pull/12618) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix error `Output of TreeExecutor is not sorted` for `OPTIMIZE DEDUPLICATE`. Fixes [#11572](https://github.com/ClickHouse/ClickHouse/issues/11572). [#12613](https://github.com/ClickHouse/ClickHouse/pull/12613) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix the issue when alias on result of function `any` can be lost during query optimization. [#12593](https://github.com/ClickHouse/ClickHouse/pull/12593) ([Anton Popov](https://github.com/CurtizJ)).
+* Remove data for Distributed tables (blocks from async INSERTs) on DROP TABLE. [#12556](https://github.com/ClickHouse/ClickHouse/pull/12556) ([Azat Khuzhin](https://github.com/azat)).
+* Now ClickHouse will recalculate checksums for parts when file `checksums.txt` is absent. Broken since [#9827](https://github.com/ClickHouse/ClickHouse/issues/9827). [#12545](https://github.com/ClickHouse/ClickHouse/pull/12545) ([alesapin](https://github.com/alesapin)).
+* Fix bug which lead to broken old parts after `ALTER DELETE` query when `enable_mixed_granularity_parts=1`. Fixes [#12536](https://github.com/ClickHouse/ClickHouse/issues/12536). [#12543](https://github.com/ClickHouse/ClickHouse/pull/12543) ([alesapin](https://github.com/alesapin)).
+* Fixing race condition in live view tables which could cause data duplication. LIVE VIEW is an experimental feature. [#12519](https://github.com/ClickHouse/ClickHouse/pull/12519) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Fix backwards compatibility in binary format of `AggregateFunction(avg, ...)` values. This fixes [#12342](https://github.com/ClickHouse/ClickHouse/issues/12342). [#12486](https://github.com/ClickHouse/ClickHouse/pull/12486) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash in JOIN with dictionary when we are joining over expression of dictionary key: `t JOIN dict ON expr(dict.id) = t.id`. Disable dictionary join optimisation for this case. [#12458](https://github.com/ClickHouse/ClickHouse/pull/12458) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix overflow when very large LIMIT or OFFSET is specified. This fixes [#10470](https://github.com/ClickHouse/ClickHouse/issues/10470). This fixes [#11372](https://github.com/ClickHouse/ClickHouse/issues/11372). [#12427](https://github.com/ClickHouse/ClickHouse/pull/12427) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* kafka: fix SIGSEGV if there is a message with error in the middle of the batch. [#12302](https://github.com/ClickHouse/ClickHouse/pull/12302) ([Azat Khuzhin](https://github.com/azat)).
+
+#### Improvement
+
+* Keep smaller amount of logs in ZooKeeper. Avoid excessive growing of ZooKeeper nodes in case of offline replicas when having many servers/tables/inserts. [#13100](https://github.com/ClickHouse/ClickHouse/pull/13100) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now exceptions forwarded to the client if an error happened during ALTER or mutation. Closes [#11329](https://github.com/ClickHouse/ClickHouse/issues/11329). [#12666](https://github.com/ClickHouse/ClickHouse/pull/12666) ([alesapin](https://github.com/alesapin)).
+* Add `QueryTimeMicroseconds`, `SelectQueryTimeMicroseconds` and `InsertQueryTimeMicroseconds` to `system.events`, along with system.metrics, processes, query_log, etc. [#13028](https://github.com/ClickHouse/ClickHouse/pull/13028) ([ianton-ru](https://github.com/ianton-ru)).
+* Added `SelectedRows` and `SelectedBytes` to `system.events`, along with system.metrics, processes, query_log, etc. [#12638](https://github.com/ClickHouse/ClickHouse/pull/12638) ([ianton-ru](https://github.com/ianton-ru)).
+* Added `current_database` information to `system.query_log`. [#12652](https://github.com/ClickHouse/ClickHouse/pull/12652) ([Amos Bird](https://github.com/amosbird)).
+* Allow `TabSeparatedRaw` as input format. [#12009](https://github.com/ClickHouse/ClickHouse/pull/12009) ([hcz](https://github.com/hczhcz)).
+* Now `joinGet` supports multi-key lookup. [#12418](https://github.com/ClickHouse/ClickHouse/pull/12418) ([Amos Bird](https://github.com/amosbird)).
+* Allow `*Map` aggregate functions to work on Arrays with NULLs. Fixes [#13157](https://github.com/ClickHouse/ClickHouse/issues/13157). [#13225](https://github.com/ClickHouse/ClickHouse/pull/13225) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Avoid overflow in parsing of DateTime values that will lead to negative unix timestamp in their timezone (for example, `1970-01-01 00:00:00` in Moscow). Saturate to zero instead. This fixes [#3470](https://github.com/ClickHouse/ClickHouse/issues/3470). This fixes [#4172](https://github.com/ClickHouse/ClickHouse/issues/4172). [#12443](https://github.com/ClickHouse/ClickHouse/pull/12443) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* AvroConfluent: Skip Kafka tombstone records - Support skipping broken records [#13203](https://github.com/ClickHouse/ClickHouse/pull/13203) ([Andrew Onyshchuk](https://github.com/oandrew)).
+* Fix wrong error for long queries. It was possible to get syntax error other than `Max query size exceeded` for correct query. [#13928](https://github.com/ClickHouse/ClickHouse/pull/13928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix data race in `lgamma` function. This race was caught only in `tsan`, no side effects really happened. [#13842](https://github.com/ClickHouse/ClickHouse/pull/13842) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix a 'Week'-interval formatting for ATTACH/ALTER/CREATE QUOTA-statements. [#13417](https://github.com/ClickHouse/ClickHouse/pull/13417) ([vladimir-golovchenko](https://github.com/vladimir-golovchenko)).
+* Now broken parts are also reported when encountered in compact part processing. Compact parts is an experimental feature. [#13282](https://github.com/ClickHouse/ClickHouse/pull/13282) ([Amos Bird](https://github.com/amosbird)).
+* Fix assert in `geohashesInBox`. This fixes [#12554](https://github.com/ClickHouse/ClickHouse/issues/12554). [#13229](https://github.com/ClickHouse/ClickHouse/pull/13229) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix assert in `parseDateTimeBestEffort`. This fixes [#12649](https://github.com/ClickHouse/ClickHouse/issues/12649). [#13227](https://github.com/ClickHouse/ClickHouse/pull/13227) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Minor optimization in Processors/PipelineExecutor: breaking out of a loop because it makes sense to do so. [#13058](https://github.com/ClickHouse/ClickHouse/pull/13058) ([Mark Papadakis](https://github.com/markpapadakis)).
+* Support TRUNCATE table without TABLE keyword. [#12653](https://github.com/ClickHouse/ClickHouse/pull/12653) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix explain query format overwrite by default. This fixes [#12541](https://github.com/ClickHouse/ClickHouse/issues/12432). [#12541](https://github.com/ClickHouse/ClickHouse/pull/12541) ([BohuTANG](https://github.com/BohuTANG)).
+* Allow to set JOIN kind and type in more standad way: `LEFT SEMI JOIN` instead of `SEMI LEFT JOIN`. For now both are correct. [#12520](https://github.com/ClickHouse/ClickHouse/pull/12520) ([Artem Zuikov](https://github.com/4ertus2)).
+* Changes default value for `multiple_joins_rewriter_version` to 2. It enables new multiple joins rewriter that knows about column names. [#12469](https://github.com/ClickHouse/ClickHouse/pull/12469) ([Artem Zuikov](https://github.com/4ertus2)).
+* Add several metrics for requests to S3 storages. [#12464](https://github.com/ClickHouse/ClickHouse/pull/12464) ([ianton-ru](https://github.com/ianton-ru)).
+* Use correct default secure port for clickhouse-benchmark with `--secure` argument. This fixes [#11044](https://github.com/ClickHouse/ClickHouse/issues/11044). [#12440](https://github.com/ClickHouse/ClickHouse/pull/12440) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Rollback insertion errors in `Log`, `TinyLog`, `StripeLog` engines. In previous versions insertion error lead to inconsisent table state (this works as documented and it is normal for these table engines). This fixes [#12402](https://github.com/ClickHouse/ClickHouse/issues/12402). [#12426](https://github.com/ClickHouse/ClickHouse/pull/12426) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Implement `RENAME DATABASE` and `RENAME DICTIONARY` for `Atomic` database engine - Add implicit `{uuid}` macro, which can be used in ZooKeeper path for `ReplicatedMergeTree`. It works with `CREATE ... ON CLUSTER ...` queries. Set `show_table_uuid_in_table_create_query_if_not_nil` to `true` to use it. - Make `ReplicatedMergeTree` engine arguments optional, `/clickhouse/tables/{uuid}/{shard}/` and `{replica}` are used by default. Closes [#12135](https://github.com/ClickHouse/ClickHouse/issues/12135). - Minor fixes. - These changes break backward compatibility of `Atomic` database engine. Previously created `Atomic` databases must be manually converted to new format. Atomic database is an experimental feature. [#12343](https://github.com/ClickHouse/ClickHouse/pull/12343) ([tavplubix](https://github.com/tavplubix)).
+* Separated `AWSAuthV4Signer` into different logger, removed excessive `AWSClient: AWSClient` from log messages. [#12320](https://github.com/ClickHouse/ClickHouse/pull/12320) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Better exception message in disk access storage. [#12625](https://github.com/ClickHouse/ClickHouse/pull/12625) ([alesapin](https://github.com/alesapin)).
+* Better exception for function `in` with invalid number of arguments. [#12529](https://github.com/ClickHouse/ClickHouse/pull/12529) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix error message about adaptive granularity. [#12624](https://github.com/ClickHouse/ClickHouse/pull/12624) ([alesapin](https://github.com/alesapin)).
+* Fix SETTINGS parse after FORMAT. [#12480](https://github.com/ClickHouse/ClickHouse/pull/12480) ([Azat Khuzhin](https://github.com/azat)).
+* If MergeTree table does not contain ORDER BY or PARTITION BY, it was possible to request ALTER to CLEAR all the columns and ALTER will stuck. Fixed [#7941](https://github.com/ClickHouse/ClickHouse/issues/7941). [#12382](https://github.com/ClickHouse/ClickHouse/pull/12382) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Avoid re-loading completion from the history file after each query (to avoid history overlaps with other client sessions). [#13086](https://github.com/ClickHouse/ClickHouse/pull/13086) ([Azat Khuzhin](https://github.com/azat)).
+
+#### Performance Improvement
+
+* Lower memory usage for some operations up to 2 times. [#12424](https://github.com/ClickHouse/ClickHouse/pull/12424) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Optimize PK lookup for queries that match exact PK range. [#12277](https://github.com/ClickHouse/ClickHouse/pull/12277) ([Ivan Babrou](https://github.com/bobrik)).
+* Slightly optimize very short queries with `LowCardinality`. [#14129](https://github.com/ClickHouse/ClickHouse/pull/14129) ([Anton Popov](https://github.com/CurtizJ)).
+* Slightly improve performance of aggregation by UInt8/UInt16 keys. [#13091](https://github.com/ClickHouse/ClickHouse/pull/13091) and [#13055](https://github.com/ClickHouse/ClickHouse/pull/13055) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Push down `LIMIT` step for query plan (inside subqueries). [#13016](https://github.com/ClickHouse/ClickHouse/pull/13016) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Parallel primary key lookup and skipping index stages on parts, as described in [#11564](https://github.com/ClickHouse/ClickHouse/issues/11564). [#12589](https://github.com/ClickHouse/ClickHouse/pull/12589) ([Ivan Babrou](https://github.com/bobrik)).
+* Converting String-type arguments of function "if" and "transform" into enum if `set optimize_if_transform_strings_to_enum = 1`. [#12515](https://github.com/ClickHouse/ClickHouse/pull/12515) ([Artem Zuikov](https://github.com/4ertus2)).
+* Replaces monotonic functions with its argument in `ORDER BY` if `set optimize_monotonous_functions_in_order_by=1`. [#12467](https://github.com/ClickHouse/ClickHouse/pull/12467) ([Artem Zuikov](https://github.com/4ertus2)).
+* Add order by optimization that rewrites `ORDER BY x, f(x)` with `ORDER by x` if `set optimize_redundant_functions_in_order_by = 1`. [#12404](https://github.com/ClickHouse/ClickHouse/pull/12404) ([Artem Zuikov](https://github.com/4ertus2)).
+* Allow pushdown predicate when subquery contains `WITH` clause. This fixes [#12293](https://github.com/ClickHouse/ClickHouse/issues/12293) [#12663](https://github.com/ClickHouse/ClickHouse/pull/12663) ([Winter Zhang](https://github.com/zhang2014)).
+* Improve performance of reading from compact parts. Compact parts is an experimental feature. [#12492](https://github.com/ClickHouse/ClickHouse/pull/12492) ([Anton Popov](https://github.com/CurtizJ)).
+* Attempt to implement streaming optimization in `DiskS3`. DiskS3 is an experimental feature. [#12434](https://github.com/ClickHouse/ClickHouse/pull/12434) ([Vladimir Chebotarev](https://github.com/excitoon)).
+
+#### Build/Testing/Packaging Improvement
+
+* Use `shellcheck` for sh tests linting. [#13200](https://github.com/ClickHouse/ClickHouse/pull/13200) [#13207](https://github.com/ClickHouse/ClickHouse/pull/13207) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add script which set labels for pull requests in GitHub hook. [#13183](https://github.com/ClickHouse/ClickHouse/pull/13183) ([alesapin](https://github.com/alesapin)).
+* Remove some of recursive submodules. See [#13378](https://github.com/ClickHouse/ClickHouse/issues/13378). [#13379](https://github.com/ClickHouse/ClickHouse/pull/13379) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Ensure that all the submodules are from proper URLs. Continuation of [#13379](https://github.com/ClickHouse/ClickHouse/issues/13379). This fixes [#13378](https://github.com/ClickHouse/ClickHouse/issues/13378). [#13397](https://github.com/ClickHouse/ClickHouse/pull/13397) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added support for user-declared settings, which can be accessed from inside queries. This is needed when ClickHouse engine is used as a component of another system. [#13013](https://github.com/ClickHouse/ClickHouse/pull/13013) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Added testing for RBAC functionality of INSERT privilege in TestFlows. Expanded tables on which SELECT is being tested. Added Requirements to match new table engine tests. [#13340](https://github.com/ClickHouse/ClickHouse/pull/13340) ([MyroTk](https://github.com/MyroTk)).
+* Fix timeout error during server restart in the stress test. [#13321](https://github.com/ClickHouse/ClickHouse/pull/13321) ([alesapin](https://github.com/alesapin)).
+* Now fast test will wait server with retries. [#13284](https://github.com/ClickHouse/ClickHouse/pull/13284) ([alesapin](https://github.com/alesapin)).
+* Function `materialize()` (the function for ClickHouse testing) will work for NULL as expected - by transforming it to non-constant column. [#13212](https://github.com/ClickHouse/ClickHouse/pull/13212) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix libunwind build in AArch64. This fixes [#13204](https://github.com/ClickHouse/ClickHouse/issues/13204). [#13208](https://github.com/ClickHouse/ClickHouse/pull/13208) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Even more retries in zkutil gtest to prevent test flakiness. [#13165](https://github.com/ClickHouse/ClickHouse/pull/13165) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Small fixes to the RBAC TestFlows. [#13152](https://github.com/ClickHouse/ClickHouse/pull/13152) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Fixing `00960_live_view_watch_events_live.py` test. [#13108](https://github.com/ClickHouse/ClickHouse/pull/13108) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Improve cache purge in documentation deploy script. [#13107](https://github.com/ClickHouse/ClickHouse/pull/13107) ([alesapin](https://github.com/alesapin)).
+* Rewrote some orphan tests to gtest. Removed useless includes from tests. [#13073](https://github.com/ClickHouse/ClickHouse/pull/13073) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Added tests for RBAC functionality of `SELECT` privilege in TestFlows. [#13061](https://github.com/ClickHouse/ClickHouse/pull/13061) ([Ritaank Tiwari](https://github.com/ritaank)).
+* Rerun some tests in fast test check. [#12992](https://github.com/ClickHouse/ClickHouse/pull/12992) ([alesapin](https://github.com/alesapin)).
+* Fix MSan error in "rdkafka" library. This closes [#12990](https://github.com/ClickHouse/ClickHouse/issues/12990). Updated `rdkafka` to version 1.5 (master). [#12991](https://github.com/ClickHouse/ClickHouse/pull/12991) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix UBSan report in base64 if tests were run on server with AVX-512. This fixes [#12318](https://github.com/ClickHouse/ClickHouse/issues/12318). Author: @qoega. [#12441](https://github.com/ClickHouse/ClickHouse/pull/12441) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix UBSan report in HDFS library. This closes [#12330](https://github.com/ClickHouse/ClickHouse/issues/12330). [#12453](https://github.com/ClickHouse/ClickHouse/pull/12453) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Check an ability that we able to restore the backup from an old version to the new version. This closes [#8979](https://github.com/ClickHouse/ClickHouse/issues/8979). [#12959](https://github.com/ClickHouse/ClickHouse/pull/12959) ([alesapin](https://github.com/alesapin)).
+* Do not build helper_container image inside integrational tests. Build docker container in CI and use pre-built helper_container in integration tests. [#12953](https://github.com/ClickHouse/ClickHouse/pull/12953) ([Ilya Yatsishin](https://github.com/qoega)).
+* Add a test for `ALTER TABLE CLEAR COLUMN` query for primary key columns. [#12951](https://github.com/ClickHouse/ClickHouse/pull/12951) ([alesapin](https://github.com/alesapin)).
+* Increased timeouts in testflows tests. [#12949](https://github.com/ClickHouse/ClickHouse/pull/12949) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Fix build of test under Mac OS X. This closes [#12767](https://github.com/ClickHouse/ClickHouse/issues/12767). [#12772](https://github.com/ClickHouse/ClickHouse/pull/12772) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Connector-ODBC updated to mysql-connector-odbc-8.0.21. [#12739](https://github.com/ClickHouse/ClickHouse/pull/12739) ([Ilya Yatsishin](https://github.com/qoega)).
+* Adding RBAC syntax tests in TestFlows. [#12642](https://github.com/ClickHouse/ClickHouse/pull/12642) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Improve performance of TestKeeper. This will speedup tests with heavy usage of Replicated tables. [#12505](https://github.com/ClickHouse/ClickHouse/pull/12505) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now we check that server is able to start after stress tests run. This fixes [#12473](https://github.com/ClickHouse/ClickHouse/issues/12473). [#12496](https://github.com/ClickHouse/ClickHouse/pull/12496) ([alesapin](https://github.com/alesapin)).
+* Update fmtlib to master (7.0.1). [#12446](https://github.com/ClickHouse/ClickHouse/pull/12446) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add docker image for fast tests. [#12294](https://github.com/ClickHouse/ClickHouse/pull/12294) ([alesapin](https://github.com/alesapin)).
+* Rework configuration paths for integration tests. [#12285](https://github.com/ClickHouse/ClickHouse/pull/12285) ([Ilya Yatsishin](https://github.com/qoega)).
+* Add compiler option to control that stack frames are not too large. This will help to run the code in fibers with small stack size. [#11524](https://github.com/ClickHouse/ClickHouse/pull/11524) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Update gitignore-files. [#13447](https://github.com/ClickHouse/ClickHouse/pull/13447) ([vladimir-golovchenko](https://github.com/vladimir-golovchenko)).
+
+
+## ClickHouse release 20.6
+
+### ClickHouse release v20.6.3.28-stable
+
+#### Backward Incompatible Change
+
+* When upgrading from versions older than 20.5, if rolling update is performed and cluster contains both versions 20.5 or greater and less than 20.5, if ClickHouse nodes with old versions are restarted and old version has been started up in presence of newer versions, it may lead to `Part ... intersects previous part` errors. To prevent this error, first install newer clickhouse-server packages on all cluster nodes and then do restarts (so, when clickhouse-server is restarted, it will start up with the new version).
+
+#### New Feature
+
+* Added an initial implementation of `EXPLAIN` query. Syntax: `EXPLAIN SELECT ...`. This fixes [#1118](https://github.com/ClickHouse/ClickHouse/issues/1118). [#11873](https://github.com/ClickHouse/ClickHouse/pull/11873) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Added storage `RabbitMQ`. [#11069](https://github.com/ClickHouse/ClickHouse/pull/11069) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Implemented PostgreSQL-like `ILIKE` operator for [#11710](https://github.com/ClickHouse/ClickHouse/issues/11710). [#12125](https://github.com/ClickHouse/ClickHouse/pull/12125) ([Mike](https://github.com/myrrc)).
+* Supported RIGHT and FULL JOIN with `SET join_algorithm = 'partial_merge'`. Only ALL strictness is allowed (ANY, SEMI, ANTI, ASOF are not). [#12118](https://github.com/ClickHouse/ClickHouse/pull/12118) ([Artem Zuikov](https://github.com/4ertus2)).
+* Added a function `initializeAggregation` to initialize an aggregation based on a single value. [#12109](https://github.com/ClickHouse/ClickHouse/pull/12109) ([Guillaume Tassery](https://github.com/YiuRULE)).
+* Supported `ALTER TABLE ... [ADD|MODIFY] COLUMN ... FIRST` [#4006](https://github.com/ClickHouse/ClickHouse/issues/4006). [#12073](https://github.com/ClickHouse/ClickHouse/pull/12073) ([Winter Zhang](https://github.com/zhang2014)).
+* Added function `parseDateTimeBestEffortUS`. [#12028](https://github.com/ClickHouse/ClickHouse/pull/12028) ([flynn](https://github.com/ucasFL)).
+* Support format `ORC` for output (was supported only for input). [#11662](https://github.com/ClickHouse/ClickHouse/pull/11662) ([Kruglov Pavel](https://github.com/Avogar)).
+
+#### Bug Fix
+
+* Fixed `aggregate function any(x) is found inside another aggregate function in query` error with `SET optimize_move_functions_out_of_any = 1` and aliases inside `any()`. [#13419](https://github.com/ClickHouse/ClickHouse/pull/13419) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixed `PrettyCompactMonoBlock` for clickhouse-local. Fixed extremes/totals with `PrettyCompactMonoBlock`. This fixes [#7746](https://github.com/ClickHouse/ClickHouse/issues/7746). [#13394](https://github.com/ClickHouse/ClickHouse/pull/13394) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed possible error `Totals having transform was already added to pipeline` in case of a query from delayed replica. [#13290](https://github.com/ClickHouse/ClickHouse/pull/13290) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* The server may crash if user passed specifically crafted arguments to the function `h3ToChildren`. This fixes [#13275](https://github.com/ClickHouse/ClickHouse/issues/13275). [#13277](https://github.com/ClickHouse/ClickHouse/pull/13277) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potentially low performance and slightly incorrect result for `uniqExact`, `topK`, `sumDistinct` and similar aggregate functions called on Float types with NaN values. It also triggered assert in debug build. This fixes [#12491](https://github.com/ClickHouse/ClickHouse/issues/12491). [#13254](https://github.com/ClickHouse/ClickHouse/pull/13254) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed function if with nullable constexpr as cond that is not literal NULL. Fixes [#12463](https://github.com/ClickHouse/ClickHouse/issues/12463). [#13226](https://github.com/ClickHouse/ClickHouse/pull/13226) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed assert in `arrayElement` function in case of array elements are Nullable and array subscript is also Nullable. This fixes [#12172](https://github.com/ClickHouse/ClickHouse/issues/12172). [#13224](https://github.com/ClickHouse/ClickHouse/pull/13224) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `DateTime64` conversion functions with constant argument. [#13205](https://github.com/ClickHouse/ClickHouse/pull/13205) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed wrong index analysis with functions. It could lead to pruning wrong parts, while reading from `MergeTree` tables. Fixes [#13060](https://github.com/ClickHouse/ClickHouse/issues/13060). Fixes [#12406](https://github.com/ClickHouse/ClickHouse/issues/12406). [#13081](https://github.com/ClickHouse/ClickHouse/pull/13081) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed error `Cannot convert column because it is constant but values of constants are different in source and result` for remote queries which use deterministic functions in scope of query, but not deterministic between queries, like `now()`, `now64()`, `randConstant()`. Fixes [#11327](https://github.com/ClickHouse/ClickHouse/issues/11327). [#13075](https://github.com/ClickHouse/ClickHouse/pull/13075) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed unnecessary limiting for the number of threads for selects from local replica. [#12840](https://github.com/ClickHouse/ClickHouse/pull/12840) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed rare bug when `ALTER DELETE` and `ALTER MODIFY COLUMN` queries executed simultaneously as a single mutation. Bug leads to an incorrect amount of rows in `count.txt` and as a consequence incorrect data in part. Also, fix a small bug with simultaneous `ALTER RENAME COLUMN` and `ALTER ADD COLUMN`. [#12760](https://github.com/ClickHouse/ClickHouse/pull/12760) ([alesapin](https://github.com/alesapin)).
+* Fixed `CAST(Nullable(String), Enum())`. [#12745](https://github.com/ClickHouse/ClickHouse/pull/12745) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed a performance with large tuples, which are interpreted as functions in `IN` section. The case when user write `WHERE x IN tuple(1, 2, ...)` instead of `WHERE x IN (1, 2, ...)` for some obscure reason. [#12700](https://github.com/ClickHouse/ClickHouse/pull/12700) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed memory tracking for `input_format_parallel_parsing` (by attaching thread to group). [#12672](https://github.com/ClickHouse/ClickHouse/pull/12672) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed bloom filter index with const expression. This fixes [#10572](https://github.com/ClickHouse/ClickHouse/issues/10572). [#12659](https://github.com/ClickHouse/ClickHouse/pull/12659) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed `SIGSEGV` in `StorageKafka` when broker is unavailable (and not only). [#12658](https://github.com/ClickHouse/ClickHouse/pull/12658) ([Azat Khuzhin](https://github.com/azat)).
+* Added support for function `if` with `Array(UUID)` arguments. This fixes [#11066](https://github.com/ClickHouse/ClickHouse/issues/11066). [#12648](https://github.com/ClickHouse/ClickHouse/pull/12648) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* `CREATE USER IF NOT EXISTS` now does not throw exception if the user exists. This fixes [#12507](https://github.com/ClickHouse/ClickHouse/issues/12507). [#12646](https://github.com/ClickHouse/ClickHouse/pull/12646) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Better exception message in disk access storage. [#12625](https://github.com/ClickHouse/ClickHouse/pull/12625) ([alesapin](https://github.com/alesapin)).
+* The function `groupArrayMoving*` was not working for distributed queries. It's result was calculated within incorrect data type (without promotion to the largest type). The function `groupArrayMovingAvg` was returning integer number that was inconsistent with the `avg` function. This fixes [#12568](https://github.com/ClickHouse/ClickHouse/issues/12568). [#12622](https://github.com/ClickHouse/ClickHouse/pull/12622) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed lack of aliases with function `any`. [#12593](https://github.com/ClickHouse/ClickHouse/pull/12593) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed race condition in external dictionaries with cache layout which can lead server crash. [#12566](https://github.com/ClickHouse/ClickHouse/pull/12566) ([alesapin](https://github.com/alesapin)).
+* Remove data for Distributed tables (blocks from async INSERTs) on DROP TABLE. [#12556](https://github.com/ClickHouse/ClickHouse/pull/12556) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed bug which lead to broken old parts after `ALTER DELETE` query when `enable_mixed_granularity_parts=1`. Fixes [#12536](https://github.com/ClickHouse/ClickHouse/issues/12536). [#12543](https://github.com/ClickHouse/ClickHouse/pull/12543) ([alesapin](https://github.com/alesapin)).
+* Better exception for function `in` with invalid number of arguments. [#12529](https://github.com/ClickHouse/ClickHouse/pull/12529) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixing race condition in live view tables which could cause data duplication. [#12519](https://github.com/ClickHouse/ClickHouse/pull/12519) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Fixed performance issue, while reading from compact parts. [#12492](https://github.com/ClickHouse/ClickHouse/pull/12492) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed backwards compatibility in binary format of `AggregateFunction(avg, ...)` values. This fixes [#12342](https://github.com/ClickHouse/ClickHouse/issues/12342). [#12486](https://github.com/ClickHouse/ClickHouse/pull/12486) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed SETTINGS parse after FORMAT. [#12480](https://github.com/ClickHouse/ClickHouse/pull/12480) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed the deadlock if `text_log` is enabled. [#12452](https://github.com/ClickHouse/ClickHouse/pull/12452) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed overflow when very large `LIMIT` or `OFFSET` is specified. This fixes [#10470](https://github.com/ClickHouse/ClickHouse/issues/10470). This fixes [#11372](https://github.com/ClickHouse/ClickHouse/issues/11372). [#12427](https://github.com/ClickHouse/ClickHouse/pull/12427) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed possible segfault if `StorageMerge`. This fixes [#12054](https://github.com/ClickHouse/ClickHouse/issues/12054). [#12401](https://github.com/ClickHouse/ClickHouse/pull/12401) ([tavplubix](https://github.com/tavplubix)).
+* Reverted change introduced in [#11079](https://github.com/ClickHouse/ClickHouse/issues/11079) to resolve [#12098](https://github.com/ClickHouse/ClickHouse/issues/12098). [#12397](https://github.com/ClickHouse/ClickHouse/pull/12397) ([Mike](https://github.com/myrrc)).
+* Additional check for arguments of bloom filter index. This fixes [#11408](https://github.com/ClickHouse/ClickHouse/issues/11408). [#12388](https://github.com/ClickHouse/ClickHouse/pull/12388) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Avoid exception when negative or floating point constant is used in WHERE condition for indexed tables. This fixes [#11905](https://github.com/ClickHouse/ClickHouse/issues/11905). [#12384](https://github.com/ClickHouse/ClickHouse/pull/12384) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allowed to `CLEAR` column even if there are depending `DEFAULT` expressions. This fixes [#12333](https://github.com/ClickHouse/ClickHouse/issues/12333). [#12378](https://github.com/ClickHouse/ClickHouse/pull/12378) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `TOTALS/ROLLUP/CUBE` for aggregate functions with `-State` and `Nullable` arguments. This fixes [#12163](https://github.com/ClickHouse/ClickHouse/issues/12163). [#12376](https://github.com/ClickHouse/ClickHouse/pull/12376) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed error message and exit codes for `ALTER RENAME COLUMN` queries, when `RENAME` is not allowed. Fixes [#12301](https://github.com/ClickHouse/ClickHouse/issues/12301) and [#12303](https://github.com/ClickHouse/ClickHouse/issues/12303). [#12335](https://github.com/ClickHouse/ClickHouse/pull/12335) ([alesapin](https://github.com/alesapin)).
+* Fixed very rare race condition in `ReplicatedMergeTreeQueue`. [#12315](https://github.com/ClickHouse/ClickHouse/pull/12315) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* When using codec `Delta` or `DoubleDelta` with non fixed width types, exception with code `LOGICAL_ERROR` was returned instead of exception with code `BAD_ARGUMENTS` (we ensure that exceptions with code logical error never happen). This fixes [#12110](https://github.com/ClickHouse/ClickHouse/issues/12110). [#12308](https://github.com/ClickHouse/ClickHouse/pull/12308) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed order of columns in `WITH FILL` modifier. Previously order of columns of `ORDER BY` statement wasn't respected. [#12306](https://github.com/ClickHouse/ClickHouse/pull/12306) ([Anton Popov](https://github.com/CurtizJ)).
+* Avoid "bad cast" exception when there is an expression that filters data by virtual columns (like `_table` in `Merge` tables) or by "index" columns in system tables such as filtering by database name when querying from `system.tables`, and this expression returns `Nullable` type. This fixes [#12166](https://github.com/ClickHouse/ClickHouse/issues/12166). [#12305](https://github.com/ClickHouse/ClickHouse/pull/12305) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `TTL` after renaming column, on which depends TTL expression. [#12304](https://github.com/ClickHouse/ClickHouse/pull/12304) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed SIGSEGV if there is an message with error in the middle of the batch in `Kafka` Engine. [#12302](https://github.com/ClickHouse/ClickHouse/pull/12302) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed the situation when some threads might randomly hang for a few seconds during `DNS` cache updating. [#12296](https://github.com/ClickHouse/ClickHouse/pull/12296) ([tavplubix](https://github.com/tavplubix)).
+* Fixed typo in setting name. [#12292](https://github.com/ClickHouse/ClickHouse/pull/12292) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Show error after `TrieDictionary` failed to load. [#12290](https://github.com/ClickHouse/ClickHouse/pull/12290) ([Vitaly Baranov](https://github.com/vitlibar)).
+* The function `arrayFill` worked incorrectly for empty arrays that may lead to crash. This fixes [#12263](https://github.com/ClickHouse/ClickHouse/issues/12263). [#12279](https://github.com/ClickHouse/ClickHouse/pull/12279) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Implement conversions to the common type for `LowCardinality` types. This allows to execute UNION ALL of tables with columns of LowCardinality and other columns. This fixes [#8212](https://github.com/ClickHouse/ClickHouse/issues/8212). This fixes [#4342](https://github.com/ClickHouse/ClickHouse/issues/4342). [#12275](https://github.com/ClickHouse/ClickHouse/pull/12275) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the behaviour on reaching redirect limit in request to `S3` storage. [#12256](https://github.com/ClickHouse/ClickHouse/pull/12256) ([ianton-ru](https://github.com/ianton-ru)).
+* Fixed the behaviour when during multiple sequential inserts in `StorageFile` header for some special types was written more than once. This fixed [#6155](https://github.com/ClickHouse/ClickHouse/issues/6155). [#12197](https://github.com/ClickHouse/ClickHouse/pull/12197) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed logical functions for UInt8 values when they are not equal to 0 or 1. [#12196](https://github.com/ClickHouse/ClickHouse/pull/12196) ([Alexander Kazakov](https://github.com/Akazz)).
+* Cap max_memory_usage* limits to the process resident memory. [#12182](https://github.com/ClickHouse/ClickHouse/pull/12182) ([Azat Khuzhin](https://github.com/azat)).
+* Fix dictGet arguments check during `GROUP BY` injective functions elimination. [#12179](https://github.com/ClickHouse/ClickHouse/pull/12179) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed the behaviour when `SummingMergeTree` engine sums up columns from partition key. Added an exception in case of explicit definition of columns to sum which intersects with partition key columns. This fixes [#7867](https://github.com/ClickHouse/ClickHouse/issues/7867). [#12173](https://github.com/ClickHouse/ClickHouse/pull/12173) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Don't split the dictionary source's table name into schema and table name itself if ODBC connection does not support schema. [#12165](https://github.com/ClickHouse/ClickHouse/pull/12165) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed wrong logic in `ALTER DELETE` that leads to deleting of records when condition evaluates to NULL. This fixes [#9088](https://github.com/ClickHouse/ClickHouse/issues/9088). This closes [#12106](https://github.com/ClickHouse/ClickHouse/issues/12106). [#12153](https://github.com/ClickHouse/ClickHouse/pull/12153) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed transform of query to send to external DBMS (e.g. MySQL, ODBC) in presense of aliases. This fixes [#12032](https://github.com/ClickHouse/ClickHouse/issues/12032). [#12151](https://github.com/ClickHouse/ClickHouse/pull/12151) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed bad code in redundant ORDER BY optimization. The bug was introduced in [#10067](https://github.com/ClickHouse/ClickHouse/issues/10067). [#12148](https://github.com/ClickHouse/ClickHouse/pull/12148) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential overflow in integer division. This fixes [#12119](https://github.com/ClickHouse/ClickHouse/issues/12119). [#12140](https://github.com/ClickHouse/ClickHouse/pull/12140) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential infinite loop in `greatCircleDistance`, `geoDistance`. This fixes [#12117](https://github.com/ClickHouse/ClickHouse/issues/12117). [#12137](https://github.com/ClickHouse/ClickHouse/pull/12137) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Normalize "pid" file handling. In previous versions the server may refuse to start if it was killed without proper shutdown and if there is another process that has the same pid as previously runned server. Also pid file may be removed in unsuccessful server startup even if there is another server running. This fixes [#3501](https://github.com/ClickHouse/ClickHouse/issues/3501). [#12133](https://github.com/ClickHouse/ClickHouse/pull/12133) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed bug which leads to incorrect table metadata in ZooKeepeer for ReplicatedVersionedCollapsingMergeTree tables. Fixes [#12093](https://github.com/ClickHouse/ClickHouse/issues/12093). [#12121](https://github.com/ClickHouse/ClickHouse/pull/12121) ([alesapin](https://github.com/alesapin)).
+* Avoid "There is no query" exception for materialized views with joins or with subqueries attached to system logs (system.query_log, metric_log, etc) or to engine=Buffer underlying table. [#12120](https://github.com/ClickHouse/ClickHouse/pull/12120) ([filimonov](https://github.com/filimonov)).
+* Fixed handling dependency of table with ENGINE=Dictionary on dictionary. This fixes [#10994](https://github.com/ClickHouse/ClickHouse/issues/10994). This fixes [#10397](https://github.com/ClickHouse/ClickHouse/issues/10397). [#12116](https://github.com/ClickHouse/ClickHouse/pull/12116) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Format `Parquet` now properly works with `LowCardinality` and `LowCardinality(Nullable)` types. Fixes [#12086](https://github.com/ClickHouse/ClickHouse/issues/12086), [#8406](https://github.com/ClickHouse/ClickHouse/issues/8406). [#12108](https://github.com/ClickHouse/ClickHouse/pull/12108) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed performance for selects with `UNION` caused by wrong limit for the total number of threads. Fixes [#12030](https://github.com/ClickHouse/ClickHouse/issues/12030). [#12103](https://github.com/ClickHouse/ClickHouse/pull/12103) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed segfault with `-StateResample` combinators. [#12092](https://github.com/ClickHouse/ClickHouse/pull/12092) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed empty `result_rows` and `result_bytes` metrics in `system.quey_log` for selects. Fixes [#11595](https://github.com/ClickHouse/ClickHouse/issues/11595). [#12089](https://github.com/ClickHouse/ClickHouse/pull/12089) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed unnecessary limiting the number of threads for selects from `VIEW`. Fixes [#11937](https://github.com/ClickHouse/ClickHouse/issues/11937). [#12085](https://github.com/ClickHouse/ClickHouse/pull/12085) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed SIGSEGV in StorageKafka on DROP TABLE. [#12075](https://github.com/ClickHouse/ClickHouse/pull/12075) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed possible crash while using wrong type for `PREWHERE`. Fixes [#12053](https://github.com/ClickHouse/ClickHouse/issues/12053), [#12060](https://github.com/ClickHouse/ClickHouse/issues/12060). [#12060](https://github.com/ClickHouse/ClickHouse/pull/12060) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed error `Cannot capture column` for higher-order functions with `Tuple(LowCardinality)` argument. Fixes [#9766](https://github.com/ClickHouse/ClickHouse/issues/9766). [#12055](https://github.com/ClickHouse/ClickHouse/pull/12055) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed constraints check if constraint is a constant expression. This fixes [#11360](https://github.com/ClickHouse/ClickHouse/issues/11360). [#12042](https://github.com/ClickHouse/ClickHouse/pull/12042) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed wrong result and potential crash when invoking function `if` with arguments of type `FixedString` with different sizes. This fixes [#11362](https://github.com/ClickHouse/ClickHouse/issues/11362). [#12021](https://github.com/ClickHouse/ClickHouse/pull/12021) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### Improvement
+
+* Allowed to set `JOIN` kind and type in more standard way: `LEFT SEMI JOIN` instead of `SEMI LEFT JOIN`. For now both are correct. [#12520](https://github.com/ClickHouse/ClickHouse/pull/12520) ([Artem Zuikov](https://github.com/4ertus2)).
+* lifetime_rows/lifetime_bytes for Buffer engine. [#12421](https://github.com/ClickHouse/ClickHouse/pull/12421) ([Azat Khuzhin](https://github.com/azat)).
+* Write the detail exception message to the client instead of 'MySQL server has gone away'. [#12383](https://github.com/ClickHouse/ClickHouse/pull/12383) ([BohuTANG](https://github.com/BohuTANG)).
+* Allows to change a charset which is used for printing grids borders. Available charsets are following: UTF-8, ASCII. Setting `output_format_pretty_grid_charset` enables this feature. [#12372](https://github.com/ClickHouse/ClickHouse/pull/12372) ([Sabyanin Maxim](https://github.com/s-mx)).
+* Supported MySQL 'SELECT DATABASE()' [#9336](https://github.com/ClickHouse/ClickHouse/issues/9336) 2. Add MySQL replacement query integration test. [#12314](https://github.com/ClickHouse/ClickHouse/pull/12314) ([BohuTANG](https://github.com/BohuTANG)).
+* Added `KILL QUERY [connection_id]` for the MySQL client/driver to cancel the long query, issue [#12038](https://github.com/ClickHouse/ClickHouse/issues/12038). [#12152](https://github.com/ClickHouse/ClickHouse/pull/12152) ([BohuTANG](https://github.com/BohuTANG)).
+* Added support for `%g` (two digit ISO year) and `%G` (four digit ISO year) substitutions in `formatDateTime` function. [#12136](https://github.com/ClickHouse/ClickHouse/pull/12136) ([vivarum](https://github.com/vivarum)).
+* Added 'type' column in system.disks. [#12115](https://github.com/ClickHouse/ClickHouse/pull/12115) ([ianton-ru](https://github.com/ianton-ru)).
+* Improved `REVOKE` command: now it requires grant/admin option for only access which will be revoked. For example, to execute `REVOKE ALL ON *.* FROM user1` now it does not require to have full access rights granted with grant option. Added command `REVOKE ALL FROM user1` - it revokes all granted roles from `user1`. [#12083](https://github.com/ClickHouse/ClickHouse/pull/12083) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Added replica priority for load_balancing (for manual prioritization of the load balancing). [#11995](https://github.com/ClickHouse/ClickHouse/pull/11995) ([Azat Khuzhin](https://github.com/azat)).
+* Switched paths in S3 metadata to relative which allows to handle S3 blobs more easily. [#11892](https://github.com/ClickHouse/ClickHouse/pull/11892) ([Vladimir Chebotarev](https://github.com/excitoon)).
+
+#### Performance Improvement
+
+* Improved performace of 'ORDER BY' and 'GROUP BY' by prefix of sorting key (enabled with `optimize_aggregation_in_order` setting, disabled by default). [#11696](https://github.com/ClickHouse/ClickHouse/pull/11696) ([Anton Popov](https://github.com/CurtizJ)).
+* Removed injective functions inside `uniq*()` if `set optimize_injective_functions_inside_uniq=1`. [#12337](https://github.com/ClickHouse/ClickHouse/pull/12337) ([Ruslan Kamalov](https://github.com/kamalov-ruslan)).
+* Index not used for IN operator with literals, performance regression introduced around v19.3. This fixes [#10574](https://github.com/ClickHouse/ClickHouse/issues/10574). [#12062](https://github.com/ClickHouse/ClickHouse/pull/12062) ([nvartolomei](https://github.com/nvartolomei)).
+* Implemented single part uploads for DiskS3 (experimental feature). [#12026](https://github.com/ClickHouse/ClickHouse/pull/12026) ([Vladimir Chebotarev](https://github.com/excitoon)).
+
+#### Experimental Feature
+* Added new in-memory format of parts in `MergeTree`-family tables, which stores data in memory. Parts are written on disk at first merge. Part will be created in in-memory format if its size in rows or bytes is below thresholds `min_rows_for_compact_part` and `min_bytes_for_compact_part`. Also optional support of Write-Ahead-Log is available, which is enabled by default and is controlled by setting `in_memory_parts_enable_wal`. [#10697](https://github.com/ClickHouse/ClickHouse/pull/10697) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Build/Testing/Packaging Improvement
+
+* Implement AST-based query fuzzing mode for clickhouse-client. See [this label](https://github.com/ClickHouse/ClickHouse/issues?q=label%3Afuzz+is%3Aissue) for the list of issues we recently found by fuzzing. Most of them were found by this tool, and a couple by SQLancer and `00746_sql_fuzzy.pl`. [#12111](https://github.com/ClickHouse/ClickHouse/pull/12111) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Add new type of tests based on Testflows framework. [#12090](https://github.com/ClickHouse/ClickHouse/pull/12090) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Added S3 HTTPS integration test. [#12412](https://github.com/ClickHouse/ClickHouse/pull/12412) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Log sanitizer trap messages from separate thread. This will prevent possible deadlock under thread sanitizer. [#12313](https://github.com/ClickHouse/ClickHouse/pull/12313) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now functional and stress tests will be able to run with old version of `clickhouse-test` script. [#12287](https://github.com/ClickHouse/ClickHouse/pull/12287) ([alesapin](https://github.com/alesapin)).
+* Remove strange file creation during build in `orc`. [#12258](https://github.com/ClickHouse/ClickHouse/pull/12258) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Place common docker compose files to integration docker container. [#12168](https://github.com/ClickHouse/ClickHouse/pull/12168) ([Ilya Yatsishin](https://github.com/qoega)).
+* Fix warnings from CodeQL. `CodeQL` is another static analyzer that we will use along with `clang-tidy` and `PVS-Studio` that we use already. [#12138](https://github.com/ClickHouse/ClickHouse/pull/12138) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Minor CMake fixes for UNBUNDLED build. [#12131](https://github.com/ClickHouse/ClickHouse/pull/12131) ([Matwey V. Kornilov](https://github.com/matwey)).
+* Added a showcase of the minimal Docker image without using any Linux distribution. [#12126](https://github.com/ClickHouse/ClickHouse/pull/12126) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Perform an upgrade of system packages in the `clickhouse-server` docker image. [#12124](https://github.com/ClickHouse/ClickHouse/pull/12124) ([Ivan Blinkov](https://github.com/blinkov)).
+* Add `UNBUNDLED` flag to `system.build_options` table. Move skip lists for `clickhouse-test` to clickhouse repo. [#12107](https://github.com/ClickHouse/ClickHouse/pull/12107) ([alesapin](https://github.com/alesapin)).
+* Regular check by [Anchore Container Analysis](https://docs.anchore.com) security analysis tool that looks for [CVE](https://cve.mitre.org/) in `clickhouse-server` Docker image. Also confirms that `Dockerfile` is buildable. Runs daily on `master` and on pull-requests to `Dockerfile`. [#12102](https://github.com/ClickHouse/ClickHouse/pull/12102) ([Ivan Blinkov](https://github.com/blinkov)).
+* Daily check by [GitHub CodeQL](https://securitylab.github.com/tools/codeql) security analysis tool that looks for [CWE](https://cwe.mitre.org/). [#12101](https://github.com/ClickHouse/ClickHouse/pull/12101) ([Ivan Blinkov](https://github.com/blinkov)).
+* Install `ca-certificates` before the first `apt-get update` in Dockerfile. [#12095](https://github.com/ClickHouse/ClickHouse/pull/12095) ([Ivan Blinkov](https://github.com/blinkov)).
+
+## ClickHouse release 20.5
+
+### ClickHouse release v20.5.4.40-stable 2020-08-10
+
+#### Bug Fix
+
+* Fixed wrong index analysis with functions. It could lead to pruning wrong parts, while reading from `MergeTree` tables. Fixes [#13060](https://github.com/ClickHouse/ClickHouse/issues/13060). Fixes [#12406](https://github.com/ClickHouse/ClickHouse/issues/12406). [#13081](https://github.com/ClickHouse/ClickHouse/pull/13081) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed unnecessary limiting for the number of threads for selects from local replica. [#12840](https://github.com/ClickHouse/ClickHouse/pull/12840) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed performance with large tuples, which are interpreted as functions in `IN` section. The case when user write `WHERE x IN tuple(1, 2, ...)` instead of `WHERE x IN (1, 2, ...)` for some obscure reason. [#12700](https://github.com/ClickHouse/ClickHouse/pull/12700) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed memory tracking for input_format_parallel_parsing (by attaching thread to group). [#12672](https://github.com/ClickHouse/ClickHouse/pull/12672) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed bloom filter index with const expression. This fixes [#10572](https://github.com/ClickHouse/ClickHouse/issues/10572). [#12659](https://github.com/ClickHouse/ClickHouse/pull/12659) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed `SIGSEGV` in `StorageKafka` when broker is unavailable (and not only). [#12658](https://github.com/ClickHouse/ClickHouse/pull/12658) ([Azat Khuzhin](https://github.com/azat)).
+* Added support for function `if` with `Array(UUID)` arguments. This fixes [#11066](https://github.com/ClickHouse/ClickHouse/issues/11066). [#12648](https://github.com/ClickHouse/ClickHouse/pull/12648) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed lack of aliases with function `any`. [#12593](https://github.com/ClickHouse/ClickHouse/pull/12593) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed race condition in external dictionaries with cache layout which can lead server crash. [#12566](https://github.com/ClickHouse/ClickHouse/pull/12566) ([alesapin](https://github.com/alesapin)).
+* Remove data for Distributed tables (blocks from async INSERTs) on DROP TABLE. [#12556](https://github.com/ClickHouse/ClickHouse/pull/12556) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed bug which lead to broken old parts after `ALTER DELETE` query when `enable_mixed_granularity_parts=1`. Fixes [#12536](https://github.com/ClickHouse/ClickHouse/issues/12536). [#12543](https://github.com/ClickHouse/ClickHouse/pull/12543) ([alesapin](https://github.com/alesapin)).
+* Better exception for function `in` with invalid number of arguments. [#12529](https://github.com/ClickHouse/ClickHouse/pull/12529) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed race condition in live view tables which could cause data duplication. [#12519](https://github.com/ClickHouse/ClickHouse/pull/12519) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Fixed performance issue, while reading from compact parts. [#12492](https://github.com/ClickHouse/ClickHouse/pull/12492) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed backwards compatibility in binary format of `AggregateFunction(avg, ...)` values. This fixes [#12342](https://github.com/ClickHouse/ClickHouse/issues/12342). [#12486](https://github.com/ClickHouse/ClickHouse/pull/12486) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the deadlock if `text_log` is enabled. [#12452](https://github.com/ClickHouse/ClickHouse/pull/12452) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed overflow when very large LIMIT or OFFSET is specified. This fixes [#10470](https://github.com/ClickHouse/ClickHouse/issues/10470). This fixes [#11372](https://github.com/ClickHouse/ClickHouse/issues/11372). [#12427](https://github.com/ClickHouse/ClickHouse/pull/12427) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed possible segfault if StorageMerge. Closes [#12054](https://github.com/ClickHouse/ClickHouse/issues/12054). [#12401](https://github.com/ClickHouse/ClickHouse/pull/12401) ([tavplubix](https://github.com/tavplubix)).
+* Reverts change introduced in [#11079](https://github.com/ClickHouse/ClickHouse/issues/11079) to resolve [#12098](https://github.com/ClickHouse/ClickHouse/issues/12098). [#12397](https://github.com/ClickHouse/ClickHouse/pull/12397) ([Mike](https://github.com/myrrc)).
+* Avoid exception when negative or floating point constant is used in WHERE condition for indexed tables. This fixes [#11905](https://github.com/ClickHouse/ClickHouse/issues/11905). [#12384](https://github.com/ClickHouse/ClickHouse/pull/12384) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow to CLEAR column even if there are depending DEFAULT expressions. This fixes [#12333](https://github.com/ClickHouse/ClickHouse/issues/12333). [#12378](https://github.com/ClickHouse/ClickHouse/pull/12378) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed TOTALS/ROLLUP/CUBE for aggregate functions with `-State` and `Nullable` arguments. This fixes [#12163](https://github.com/ClickHouse/ClickHouse/issues/12163). [#12376](https://github.com/ClickHouse/ClickHouse/pull/12376) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed SIGSEGV if there is an message with error in the middle of the batch in `Kafka` Engine. [#12302](https://github.com/ClickHouse/ClickHouse/pull/12302) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed the behaviour when `SummingMergeTree` engine sums up columns from partition key. Added an exception in case of explicit definition of columns to sum which intersects with partition key columns. This fixes [#7867](https://github.com/ClickHouse/ClickHouse/issues/7867). [#12173](https://github.com/ClickHouse/ClickHouse/pull/12173) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed transform of query to send to external DBMS (e.g. MySQL, ODBC) in presense of aliases. This fixes [#12032](https://github.com/ClickHouse/ClickHouse/issues/12032). [#12151](https://github.com/ClickHouse/ClickHouse/pull/12151) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed bug which leads to incorrect table metadata in ZooKeepeer for ReplicatedVersionedCollapsingMergeTree tables. Fixes [#12093](https://github.com/ClickHouse/ClickHouse/issues/12093). [#12121](https://github.com/ClickHouse/ClickHouse/pull/12121) ([alesapin](https://github.com/alesapin)).
+* Fixed unnecessary limiting the number of threads for selects from `VIEW`. Fixes [#11937](https://github.com/ClickHouse/ClickHouse/issues/11937). [#12085](https://github.com/ClickHouse/ClickHouse/pull/12085) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed crash in JOIN with LowCardinality type with `join_algorithm=partial_merge`. [#12035](https://github.com/ClickHouse/ClickHouse/pull/12035) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixed wrong result for `if()` with NULLs in condition. [#11807](https://github.com/ClickHouse/ClickHouse/pull/11807) ([Artem Zuikov](https://github.com/4ertus2)).
+
+#### Performance Improvement
+
+* Index not used for IN operator with literals, performance regression introduced around v19.3. This fixes [#10574](https://github.com/ClickHouse/ClickHouse/issues/10574). [#12062](https://github.com/ClickHouse/ClickHouse/pull/12062) ([nvartolomei](https://github.com/nvartolomei)).
+
+#### Build/Testing/Packaging Improvement
+
+* Install `ca-certificates` before the first `apt-get update` in Dockerfile. [#12095](https://github.com/ClickHouse/ClickHouse/pull/12095) ([Ivan Blinkov](https://github.com/blinkov)).
+
+
+### ClickHouse release v20.5.2.7-stable 2020-07-02
+
+#### Backward Incompatible Change
+
+* Return non-Nullable result from COUNT(DISTINCT), and `uniq` aggregate functions family. If all passed values are NULL, return zero instead. This improves SQL compatibility. [#11661](https://github.com/ClickHouse/ClickHouse/pull/11661) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added a check for the case when user-level setting is specified in a wrong place. User-level settings should be specified in `users.xml` inside `<profile>` section for specific user profile (or in `<default>` for default settings). The server won't start with exception message in log. This fixes [#9051](https://github.com/ClickHouse/ClickHouse/issues/9051). If you want to skip the check, you can either move settings to the appropriate place or add `<skip_check_for_incorrect_settings>1</skip_check_for_incorrect_settings>` to config.xml. [#11449](https://github.com/ClickHouse/ClickHouse/pull/11449) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* The setting `input_format_with_names_use_header` is enabled by default. It will affect parsing of input formats `-WithNames` and `-WithNamesAndTypes`. [#10937](https://github.com/ClickHouse/ClickHouse/pull/10937) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove `experimental_use_processors` setting. It is enabled by default. [#10924](https://github.com/ClickHouse/ClickHouse/pull/10924) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Update `zstd` to 1.4.4. It has some minor improvements in performance and compression ratio. If you run replicas with different versions of ClickHouse you may see reasonable error messages `Data after merge is not byte-identical to data on another replicas.` with explanation. These messages are Ok and you should not worry. This change is backward compatible but we list it here in changelog in case you will wonder about these messages. [#10663](https://github.com/ClickHouse/ClickHouse/pull/10663) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added a check for meaningless codecs and a setting `allow_suspicious_codecs` to control this check. This closes [#4966](https://github.com/ClickHouse/ClickHouse/issues/4966). [#10645](https://github.com/ClickHouse/ClickHouse/pull/10645) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Several Kafka setting changes their defaults. See [#11388](https://github.com/ClickHouse/ClickHouse/pull/11388).
+* When upgrading from versions older than 20.5, if rolling update is performed and cluster contains both versions 20.5 or greater and less than 20.5, if ClickHouse nodes with old versions are restarted and old version has been started up in presence of newer versions, it may lead to `Part ... intersects previous part` errors. To prevent this error, first install newer clickhouse-server packages on all cluster nodes and then do restarts (so, when clickhouse-server is restarted, it will start up with the new version).
+
+#### New Feature
+
+* `TTL DELETE WHERE` and `TTL GROUP BY` for automatic data coarsening and rollup in tables. [#10537](https://github.com/ClickHouse/ClickHouse/pull/10537) ([expl0si0nn](https://github.com/expl0si0nn)).
+* Implementation of PostgreSQL wire protocol. [#10242](https://github.com/ClickHouse/ClickHouse/pull/10242) ([Movses](https://github.com/MovElb)).
+* Added system tables for users, roles, grants, settings profiles, quotas, row policies; added commands SHOW USER, SHOW [CURRENT|ENABLED] ROLES, SHOW SETTINGS PROFILES. [#10387](https://github.com/ClickHouse/ClickHouse/pull/10387) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Support writes in ODBC Table function [#10554](https://github.com/ClickHouse/ClickHouse/pull/10554) ([ageraab](https://github.com/ageraab)). [#10901](https://github.com/ClickHouse/ClickHouse/pull/10901) ([tavplubix](https://github.com/tavplubix)).
+* Add query performance metrics based on Linux `perf_events` (these metrics are calculated with hardware CPU counters and OS counters). It is optional and requires `CAP_SYS_ADMIN` to be set on clickhouse binary. [#9545](https://github.com/ClickHouse/ClickHouse/pull/9545) [Andrey Skobtsov](https://github.com/And42). [#11226](https://github.com/ClickHouse/ClickHouse/pull/11226) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Now support `NULL` and `NOT NULL` modifiers for data types in `CREATE` query. [#11057](https://github.com/ClickHouse/ClickHouse/pull/11057) ([Павел Потемкин](https://github.com/Potya)).
+* Add `ArrowStream` input and output format. [#11088](https://github.com/ClickHouse/ClickHouse/pull/11088) ([hcz](https://github.com/hczhcz)).
+* Support Cassandra as external dictionary source. [#4978](https://github.com/ClickHouse/ClickHouse/pull/4978) ([favstovol](https://github.com/favstovol)).
+* Added a new layout `direct` which loads all the data directly from the source for each query, without storing or caching data. [#10622](https://github.com/ClickHouse/ClickHouse/pull/10622) ([Artem Streltsov](https://github.com/kekekekule)).
+* Added new `complex_key_direct` layout to dictionaries, that does not store anything locally during query execution. [#10850](https://github.com/ClickHouse/ClickHouse/pull/10850) ([Artem Streltsov](https://github.com/kekekekule)).
+* Added support for MySQL style global variables syntax (stub). This is needed for compatibility of MySQL protocol. [#11832](https://github.com/ClickHouse/ClickHouse/pull/11832) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added syntax highligting to `clickhouse-client` using `replxx`. [#11422](https://github.com/ClickHouse/ClickHouse/pull/11422) ([Tagir Kuskarov](https://github.com/kuskarov)).
+* `minMap` and `maxMap` functions were added. [#11603](https://github.com/ClickHouse/ClickHouse/pull/11603) ([Ildus Kurbangaliev](https://github.com/ildus)).
+* Add the `system.asynchronous_metric_log` table that logs historical metrics from `system.asynchronous_metrics`. [#11588](https://github.com/ClickHouse/ClickHouse/pull/11588) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Add functions `extractAllGroupsHorizontal(haystack, re)` and `extractAllGroupsVertical(haystack, re)`. [#11554](https://github.com/ClickHouse/ClickHouse/pull/11554) ([Vasily Nemkov](https://github.com/Enmk)).
+* Add SHOW CLUSTER(S) queries. [#11467](https://github.com/ClickHouse/ClickHouse/pull/11467) ([hexiaoting](https://github.com/hexiaoting)).
+* Add `netloc` function for extracting network location, similar to `urlparse(url)`, `netloc` in python. [#11356](https://github.com/ClickHouse/ClickHouse/pull/11356) ([Guillaume Tassery](https://github.com/YiuRULE)).
+* Add 2 more virtual columns for engine=Kafka to access message headers. [#11283](https://github.com/ClickHouse/ClickHouse/pull/11283) ([filimonov](https://github.com/filimonov)).
+* Add `_timestamp_ms` virtual column for Kafka engine (type is `Nullable(DateTime64(3))`). [#11260](https://github.com/ClickHouse/ClickHouse/pull/11260) ([filimonov](https://github.com/filimonov)).
+* Add function `randomFixedString`. [#10866](https://github.com/ClickHouse/ClickHouse/pull/10866) ([Andrei Nekrashevich](https://github.com/xolm)).
+* Add function `fuzzBits` that randomly flips bits in a string with given probability. [#11237](https://github.com/ClickHouse/ClickHouse/pull/11237) ([Andrei Nekrashevich](https://github.com/xolm)).
+* Allow comparison of numbers with constant string in comparison operators, IN and VALUES sections. [#11647](https://github.com/ClickHouse/ClickHouse/pull/11647) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add `round_robin` load_balancing mode. [#11645](https://github.com/ClickHouse/ClickHouse/pull/11645) ([Azat Khuzhin](https://github.com/azat)).
+* Add `cast_keep_nullable` setting. If set `CAST(something_nullable AS Type)` return `Nullable(Type)`. [#11733](https://github.com/ClickHouse/ClickHouse/pull/11733) ([Artem Zuikov](https://github.com/4ertus2)).
+* Added column `position` to `system.columns` table and `column_position` to `system.parts_columns` table. It contains ordinal position of a column in a table starting with 1. This closes [#7744](https://github.com/ClickHouse/ClickHouse/issues/7744). [#11655](https://github.com/ClickHouse/ClickHouse/pull/11655) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* ON CLUSTER support for SYSTEM {FLUSH DISTRIBUTED,STOP/START DISTRIBUTED SEND}. [#11415](https://github.com/ClickHouse/ClickHouse/pull/11415) ([Azat Khuzhin](https://github.com/azat)).
+* Add system.distribution_queue table. [#11394](https://github.com/ClickHouse/ClickHouse/pull/11394) ([Azat Khuzhin](https://github.com/azat)).
+* Support for all format settings in Kafka, expose some setting on table level, adjust the defaults for better performance. [#11388](https://github.com/ClickHouse/ClickHouse/pull/11388) ([filimonov](https://github.com/filimonov)).
+* Add `port` function (to extract port from URL). [#11120](https://github.com/ClickHouse/ClickHouse/pull/11120) ([Azat Khuzhin](https://github.com/azat)).
+* Now `dictGet*` functions accept table names. [#11050](https://github.com/ClickHouse/ClickHouse/pull/11050) ([Vitaly Baranov](https://github.com/vitlibar)).
+* The `clickhouse-format` tool is now able to format multiple queries when the `-n` argument is used. [#10852](https://github.com/ClickHouse/ClickHouse/pull/10852) ([Darío](https://github.com/dgrr)).
+* Possibility to configure proxy-resolver for DiskS3. [#10744](https://github.com/ClickHouse/ClickHouse/pull/10744) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Make `pointInPolygon` work with non-constant polygon. PointInPolygon now can take Array(Array(Tuple(..., ...))) as second argument, array of polygon and holes. [#10623](https://github.com/ClickHouse/ClickHouse/pull/10623) ([Alexey Ilyukhov](https://github.com/livace)) [#11421](https://github.com/ClickHouse/ClickHouse/pull/11421) ([Alexey Ilyukhov](https://github.com/livace)).
+* Added `move_ttl_info` to `system.parts` in order to provide introspection of move TTL functionality. [#10591](https://github.com/ClickHouse/ClickHouse/pull/10591) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Possibility to work with S3 through proxies. [#10576](https://github.com/ClickHouse/ClickHouse/pull/10576) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Add `NCHAR` and `NVARCHAR` synonims for data types. [#11025](https://github.com/ClickHouse/ClickHouse/pull/11025) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Resolved [#7224](https://github.com/ClickHouse/ClickHouse/issues/7224): added `FailedQuery`, `FailedSelectQuery` and `FailedInsertQuery` metrics to `system.events` table. [#11151](https://github.com/ClickHouse/ClickHouse/pull/11151) ([Nikita Orlov](https://github.com/naorlov)).
+* Add more `jemalloc` statistics to `system.asynchronous_metrics`, and ensure that we see up-to-date values for them. [#11748](https://github.com/ClickHouse/ClickHouse/pull/11748) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Allow to specify default S3 credentials and custom auth headers. [#11134](https://github.com/ClickHouse/ClickHouse/pull/11134) ([Grigory Pervakov](https://github.com/GrigoryPervakov)).
+* Added new functions to import/export DateTime64 as Int64 with various precision: `to-/fromUnixTimestamp64Milli/-Micro/-Nano`. [#10923](https://github.com/ClickHouse/ClickHouse/pull/10923) ([Vasily Nemkov](https://github.com/Enmk)).
+* Allow specifying `mongodb://` URI for MongoDB dictionaries. [#10915](https://github.com/ClickHouse/ClickHouse/pull/10915) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* OFFSET keyword can now be used without an affiliated LIMIT clause. [#10802](https://github.com/ClickHouse/ClickHouse/pull/10802) ([Guillaume Tassery](https://github.com/YiuRULE)).
+* Added `system.licenses` table. This table contains licenses of third-party libraries that are located in `contrib` directory. This closes [#2890](https://github.com/ClickHouse/ClickHouse/issues/2890). [#10795](https://github.com/ClickHouse/ClickHouse/pull/10795) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* New function function toStartOfSecond(DateTime64) -> DateTime64 that nullifies sub-second part of DateTime64 value. [#10722](https://github.com/ClickHouse/ClickHouse/pull/10722) ([Vasily Nemkov](https://github.com/Enmk)).
+* Add new input format `JSONAsString` that accepts a sequence of JSON objects separated by newlines, spaces and/or commas. [#10607](https://github.com/ClickHouse/ClickHouse/pull/10607) ([Kruglov Pavel](https://github.com/Avogar)).
+* Allowed to profile memory with finer granularity steps than 4 MiB. Added sampling memory profiler to capture random allocations/deallocations. [#10598](https://github.com/ClickHouse/ClickHouse/pull/10598) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* `SimpleAggregateFunction` now also supports `sumMap`. [#10000](https://github.com/ClickHouse/ClickHouse/pull/10000) ([Ildus Kurbangaliev](https://github.com/ildus)).
+* Support `ALTER RENAME COLUMN` for the distributed table engine. Continuation of [#10727](https://github.com/ClickHouse/ClickHouse/issues/10727). Fixes [#10747](https://github.com/ClickHouse/ClickHouse/issues/10747). [#10887](https://github.com/ClickHouse/ClickHouse/pull/10887) ([alesapin](https://github.com/alesapin)).
+
+#### Bug Fix
+
+* Fix UBSan report in Decimal parse. This fixes [#7540](https://github.com/ClickHouse/ClickHouse/issues/7540). [#10512](https://github.com/ClickHouse/ClickHouse/pull/10512) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix potential floating point exception when parsing DateTime64. This fixes [#11374](https://github.com/ClickHouse/ClickHouse/issues/11374). [#11875](https://github.com/ClickHouse/ClickHouse/pull/11875) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix rare crash caused by using `Nullable` column in prewhere condition. [#11895](https://github.com/ClickHouse/ClickHouse/pull/11895) [#11608](https://github.com/ClickHouse/ClickHouse/issues/11608) [#11869](https://github.com/ClickHouse/ClickHouse/pull/11869) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Don't allow arrayJoin inside higher order functions. It was leading to broken protocol synchronization. This closes [#3933](https://github.com/ClickHouse/ClickHouse/issues/3933). [#11846](https://github.com/ClickHouse/ClickHouse/pull/11846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix wrong result of comparison of FixedString with constant String. This fixes [#11393](https://github.com/ClickHouse/ClickHouse/issues/11393). This bug appeared in version 20.4. [#11828](https://github.com/ClickHouse/ClickHouse/pull/11828) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix wrong result for `if` with NULLs in condition. [#11807](https://github.com/ClickHouse/ClickHouse/pull/11807) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix using too many threads for queries. [#11788](https://github.com/ClickHouse/ClickHouse/pull/11788) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed `Scalar does not exist` exception when using `WITH <scalar subquery> ...` in `SELECT ... FROM merge_tree_table ...` [#11621](https://github.com/ClickHouse/ClickHouse/issues/11621). [#11767](https://github.com/ClickHouse/ClickHouse/pull/11767) ([Amos Bird](https://github.com/amosbird)).
+* Fix unexpected behaviour of queries like `SELECT *, xyz.*` which were success while an error expected. [#11753](https://github.com/ClickHouse/ClickHouse/pull/11753) ([hexiaoting](https://github.com/hexiaoting)).
+* Now replicated fetches will be cancelled during metadata alter. [#11744](https://github.com/ClickHouse/ClickHouse/pull/11744) ([alesapin](https://github.com/alesapin)).
+* Parse metadata stored in zookeeper before checking for equality. [#11739](https://github.com/ClickHouse/ClickHouse/pull/11739) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed LOGICAL_ERROR caused by wrong type deduction of complex literals in Values input format. [#11732](https://github.com/ClickHouse/ClickHouse/pull/11732) ([tavplubix](https://github.com/tavplubix)).
+* Fix `ORDER BY ... WITH FILL` over const columns. [#11697](https://github.com/ClickHouse/ClickHouse/pull/11697) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix very rare race condition in SYSTEM SYNC REPLICA. If the replicated table is created and at the same time from the separate connection another client is issuing `SYSTEM SYNC REPLICA` command on that table (this is unlikely, because another client should be aware that the table is created), it's possible to get nullptr dereference. [#11691](https://github.com/ClickHouse/ClickHouse/pull/11691) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Pass proper timeouts when communicating with XDBC bridge. Recently timeouts were not respected when checking bridge liveness and receiving meta info. [#11690](https://github.com/ClickHouse/ClickHouse/pull/11690) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `LIMIT n WITH TIES` usage together with `ORDER BY` statement, which contains aliases. [#11689](https://github.com/ClickHouse/ClickHouse/pull/11689) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix possible `Pipeline stuck` for selects with parallel `FINAL`. Fixes [#11636](https://github.com/ClickHouse/ClickHouse/issues/11636). [#11682](https://github.com/ClickHouse/ClickHouse/pull/11682) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix error which leads to an incorrect state of `system.mutations`. It may show that whole mutation is already done but the server still has `MUTATE_PART` tasks in the replication queue and tries to execute them. This fixes [#11611](https://github.com/ClickHouse/ClickHouse/issues/11611). [#11681](https://github.com/ClickHouse/ClickHouse/pull/11681) ([alesapin](https://github.com/alesapin)).
+* Fix syntax hilite in CREATE USER query. [#11664](https://github.com/ClickHouse/ClickHouse/pull/11664) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add support for regular expressions with case-insensitive flags. This fixes [#11101](https://github.com/ClickHouse/ClickHouse/issues/11101) and fixes [#11506](https://github.com/ClickHouse/ClickHouse/issues/11506). [#11649](https://github.com/ClickHouse/ClickHouse/pull/11649) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove trivial count query optimization if row-level security is set. In previous versions the user get total count of records in a table instead filtered. This fixes [#11352](https://github.com/ClickHouse/ClickHouse/issues/11352). [#11644](https://github.com/ClickHouse/ClickHouse/pull/11644) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bloom filters for String (data skipping indices). [#11638](https://github.com/ClickHouse/ClickHouse/pull/11638) ([Azat Khuzhin](https://github.com/azat)).
+* Without `-q` option the database does not get created at startup. [#11604](https://github.com/ClickHouse/ClickHouse/pull/11604) ([giordyb](https://github.com/giordyb)).
+* Fix error `Block structure mismatch` for queries with sampling reading from `Buffer` table. [#11602](https://github.com/ClickHouse/ClickHouse/pull/11602) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix wrong exit code of the clickhouse-client, when `exception.code() % 256 == 0`. [#11601](https://github.com/ClickHouse/ClickHouse/pull/11601) ([filimonov](https://github.com/filimonov)).
+* Fix race conditions in CREATE/DROP of different replicas of ReplicatedMergeTree. Continue to work if the table was not removed completely from ZooKeeper or not created successfully. This fixes [#11432](https://github.com/ClickHouse/ClickHouse/issues/11432). [#11592](https://github.com/ClickHouse/ClickHouse/pull/11592) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix trivial error in log message about "Mark cache size was lowered" at server startup. This closes [#11399](https://github.com/ClickHouse/ClickHouse/issues/11399). [#11589](https://github.com/ClickHouse/ClickHouse/pull/11589) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix error `Size of offsets does not match size of column` for queries with `PREWHERE column in (subquery)` and `ARRAY JOIN`. [#11580](https://github.com/ClickHouse/ClickHouse/pull/11580) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed rare segfault in `SHOW CREATE TABLE` Fixes [#11490](https://github.com/ClickHouse/ClickHouse/issues/11490). [#11579](https://github.com/ClickHouse/ClickHouse/pull/11579) ([tavplubix](https://github.com/tavplubix)).
+* All queries in HTTP session have had the same query_id. It is fixed. [#11578](https://github.com/ClickHouse/ClickHouse/pull/11578) ([tavplubix](https://github.com/tavplubix)).
+* Now clickhouse-server docker container will prefer IPv6 checking server aliveness. [#11550](https://github.com/ClickHouse/ClickHouse/pull/11550) ([Ivan Starkov](https://github.com/istarkov)).
+* Fix the error `Data compressed with different methods` that can happen if `min_bytes_to_use_direct_io` is enabled and PREWHERE is active and using SAMPLE or high number of threads. This fixes [#11539](https://github.com/ClickHouse/ClickHouse/issues/11539). [#11540](https://github.com/ClickHouse/ClickHouse/pull/11540) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix shard_num/replica_num for `<node>` (breaks use_compact_format_in_distributed_parts_names). [#11528](https://github.com/ClickHouse/ClickHouse/pull/11528) ([Azat Khuzhin](https://github.com/azat)).
+* Fix async INSERT into Distributed for prefer_localhost_replica=0 and w/o internal_replication. [#11527](https://github.com/ClickHouse/ClickHouse/pull/11527) ([Azat Khuzhin](https://github.com/azat)).
+* Fix memory leak when exception is thrown in the middle of aggregation with `-State` functions. This fixes [#8995](https://github.com/ClickHouse/ClickHouse/issues/8995). [#11496](https://github.com/ClickHouse/ClickHouse/pull/11496) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `Pipeline stuck` exception for `INSERT SELECT FINAL` where `SELECT` (`max_threads`>1) has multiple streams but `INSERT` has only one (`max_insert_threads`==0). [#11455](https://github.com/ClickHouse/ClickHouse/pull/11455) ([Azat Khuzhin](https://github.com/azat)).
+* Fix wrong result in queries like `select count() from t, u`. [#11454](https://github.com/ClickHouse/ClickHouse/pull/11454) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix return compressed size for codecs. [#11448](https://github.com/ClickHouse/ClickHouse/pull/11448) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix server crash when a column has compression codec with non-literal arguments. Fixes [#11365](https://github.com/ClickHouse/ClickHouse/issues/11365). [#11431](https://github.com/ClickHouse/ClickHouse/pull/11431) ([alesapin](https://github.com/alesapin)).
+* Fix potential uninitialized memory read in MergeTree shutdown if table was not created successfully. [#11420](https://github.com/ClickHouse/ClickHouse/pull/11420) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash in JOIN over `LowCarinality(T)` and `Nullable(T)`. [#11380](https://github.com/ClickHouse/ClickHouse/issues/11380). [#11414](https://github.com/ClickHouse/ClickHouse/pull/11414) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix error code for wrong `USING` key. [#11373](https://github.com/ClickHouse/ClickHouse/issues/11373). [#11404](https://github.com/ClickHouse/ClickHouse/pull/11404) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixed `geohashesInBox` with arguments outside of latitude/longitude range. [#11403](https://github.com/ClickHouse/ClickHouse/pull/11403) ([Vasily Nemkov](https://github.com/Enmk)).
+* Better errors for `joinGet()` functions. [#11389](https://github.com/ClickHouse/ClickHouse/pull/11389) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix possible `Pipeline stuck` error for queries with external sort and limit. Fixes [#11359](https://github.com/ClickHouse/ClickHouse/issues/11359). [#11366](https://github.com/ClickHouse/ClickHouse/pull/11366) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Remove redundant lock during parts send in ReplicatedMergeTree. [#11354](https://github.com/ClickHouse/ClickHouse/pull/11354) ([alesapin](https://github.com/alesapin)).
+* Fix support for `\G` (vertical output) in clickhouse-client in multiline mode. This closes [#9933](https://github.com/ClickHouse/ClickHouse/issues/9933). [#11350](https://github.com/ClickHouse/ClickHouse/pull/11350) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix potential segfault when using `Lazy` database. [#11348](https://github.com/ClickHouse/ClickHouse/pull/11348) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash in direct selects from `Join` table engine (without JOIN) and wrong nullability. [#11340](https://github.com/ClickHouse/ClickHouse/pull/11340) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix crash in `quantilesExactWeightedArray`. [#11337](https://github.com/ClickHouse/ClickHouse/pull/11337) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Now merges stopped before change metadata in `ALTER` queries. [#11335](https://github.com/ClickHouse/ClickHouse/pull/11335) ([alesapin](https://github.com/alesapin)).
+* Make writing to `MATERIALIZED VIEW` with setting `parallel_view_processing = 1` parallel again. Fixes [#10241](https://github.com/ClickHouse/ClickHouse/issues/10241). [#11330](https://github.com/ClickHouse/ClickHouse/pull/11330) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix `visitParamExtractRaw` when extracted JSON has strings with unbalanced { or [. [#11318](https://github.com/ClickHouse/ClickHouse/pull/11318) ([Ewout](https://github.com/devwout)).
+* Fix very rare race condition in ThreadPool. [#11314](https://github.com/ClickHouse/ClickHouse/pull/11314) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix insignificant data race in `clickhouse-copier`. Found by integration tests. [#11313](https://github.com/ClickHouse/ClickHouse/pull/11313) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix potential uninitialized memory in conversion. Example: `SELECT toIntervalSecond(now64())`. [#11311](https://github.com/ClickHouse/ClickHouse/pull/11311) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix the issue when index analysis cannot work if a table has Array column in primary key and if a query is filtering by this column with `empty` or `notEmpty` functions. This fixes [#11286](https://github.com/ClickHouse/ClickHouse/issues/11286). [#11303](https://github.com/ClickHouse/ClickHouse/pull/11303) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bug when query speed estimation can be incorrect and the limit of `min_execution_speed` may not work or work incorrectly if the query is throttled by `max_network_bandwidth`, `max_execution_speed` or `priority` settings. Change the default value of `timeout_before_checking_execution_speed` to non-zero, because otherwise the settings `min_execution_speed` and `max_execution_speed` have no effect. This fixes [#11297](https://github.com/ClickHouse/ClickHouse/issues/11297). This fixes [#5732](https://github.com/ClickHouse/ClickHouse/issues/5732). This fixes [#6228](https://github.com/ClickHouse/ClickHouse/issues/6228). Usability improvement: avoid concatenation of exception message with progress bar in `clickhouse-client`. [#11296](https://github.com/ClickHouse/ClickHouse/pull/11296) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash when `SET DEFAULT ROLE` is called with wrong arguments. This fixes [#10586](https://github.com/ClickHouse/ClickHouse/issues/10586). [#11278](https://github.com/ClickHouse/ClickHouse/pull/11278) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix crash while reading malformed data in `Protobuf` format. This fixes [#5957](https://github.com/ClickHouse/ClickHouse/issues/5957), fixes [#11203](https://github.com/ClickHouse/ClickHouse/issues/11203). [#11258](https://github.com/ClickHouse/ClickHouse/pull/11258) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed a bug when `cache` dictionary could return default value instead of normal (when there are only expired keys). This affects only string fields. [#11233](https://github.com/ClickHouse/ClickHouse/pull/11233) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix error `Block structure mismatch in QueryPipeline` while reading from `VIEW` with constants in inner query. Fixes [#11181](https://github.com/ClickHouse/ClickHouse/issues/11181). [#11205](https://github.com/ClickHouse/ClickHouse/pull/11205) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix possible exception `Invalid status for associated output`. [#11200](https://github.com/ClickHouse/ClickHouse/pull/11200) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Now `primary.idx` will be checked if it's defined in `CREATE` query. [#11199](https://github.com/ClickHouse/ClickHouse/pull/11199) ([alesapin](https://github.com/alesapin)).
+* Fix possible error `Cannot capture column` for higher-order functions with `Array(Array(LowCardinality))` captured argument. [#11185](https://github.com/ClickHouse/ClickHouse/pull/11185) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed `S3` globbing which could fail in case of more than 1000 keys and some backends. [#11179](https://github.com/ClickHouse/ClickHouse/pull/11179) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* If data skipping index is dependent on columns that are going to be modified during background merge (for SummingMergeTree, AggregatingMergeTree as well as for TTL GROUP BY), it was calculated incorrectly. This issue is fixed by moving index calculation after merge so the index is calculated on merged data. [#11162](https://github.com/ClickHouse/ClickHouse/pull/11162) ([Azat Khuzhin](https://github.com/azat)).
+* Fix for the hang which was happening sometimes during DROP of table engine=Kafka (or during server restarts). [#11145](https://github.com/ClickHouse/ClickHouse/pull/11145) ([filimonov](https://github.com/filimonov)).
+* Fix excessive reserving of threads for simple queries (optimization for reducing the number of threads, which was partly broken after changes in pipeline). [#11114](https://github.com/ClickHouse/ClickHouse/pull/11114) ([Azat Khuzhin](https://github.com/azat)).
+* Remove logging from mutation finalization task if nothing was finalized. [#11109](https://github.com/ClickHouse/ClickHouse/pull/11109) ([alesapin](https://github.com/alesapin)).
+* Fixed deadlock during server startup after update with changes in structure of system log tables. [#11106](https://github.com/ClickHouse/ClickHouse/pull/11106) ([alesapin](https://github.com/alesapin)).
+* Fixed memory leak in registerDiskS3. [#11074](https://github.com/ClickHouse/ClickHouse/pull/11074) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fix error `No such name in Block::erase()` when JOIN appears with PREWHERE or `optimize_move_to_prewhere` makes PREWHERE from WHERE. [#11051](https://github.com/ClickHouse/ClickHouse/pull/11051) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixes the potential missed data during termination of Kafka engine table. [#11048](https://github.com/ClickHouse/ClickHouse/pull/11048) ([filimonov](https://github.com/filimonov)).
+* Fixed parseDateTime64BestEffort argument resolution bugs. [#10925](https://github.com/ClickHouse/ClickHouse/issues/10925). [#11038](https://github.com/ClickHouse/ClickHouse/pull/11038) ([Vasily Nemkov](https://github.com/Enmk)).
+* Now it's possible to `ADD/DROP` and `RENAME` the same one column in a single `ALTER` query. Exception message for simultaneous `MODIFY` and `RENAME` became more clear. Partially fixes [#10669](https://github.com/ClickHouse/ClickHouse/issues/10669). [#11037](https://github.com/ClickHouse/ClickHouse/pull/11037) ([alesapin](https://github.com/alesapin)).
+* Fixed parsing of S3 URLs. [#11036](https://github.com/ClickHouse/ClickHouse/pull/11036) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fix memory tracking for two-level `GROUP BY` when there is a `LIMIT`. [#11022](https://github.com/ClickHouse/ClickHouse/pull/11022) ([Azat Khuzhin](https://github.com/azat)).
+* Fix very rare potential use-after-free error in MergeTree if table was not created successfully. [#10986](https://github.com/ClickHouse/ClickHouse/pull/10986) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix metadata (relative path for rename) and data (relative path for symlink) handling for Atomic database. [#10980](https://github.com/ClickHouse/ClickHouse/pull/10980) ([Azat Khuzhin](https://github.com/azat)).
+* Fix server crash on concurrent `ALTER` and `DROP DATABASE` queries with `Atomic` database engine. [#10968](https://github.com/ClickHouse/ClickHouse/pull/10968) ([tavplubix](https://github.com/tavplubix)).
+* Fix incorrect raw data size in method getRawData(). [#10964](https://github.com/ClickHouse/ClickHouse/pull/10964) ([Igr](https://github.com/ObjatieGroba)).
+* Fix incompatibility of two-level aggregation between versions 20.1 and earlier. This incompatibility happens when different versions of ClickHouse are used on initiator node and remote nodes and the size of GROUP BY result is large and aggregation is performed by a single String field. It leads to several unmerged rows for a single key in result. [#10952](https://github.com/ClickHouse/ClickHouse/pull/10952) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Avoid sending partially written files by the DistributedBlockOutputStream. [#10940](https://github.com/ClickHouse/ClickHouse/pull/10940) ([Azat Khuzhin](https://github.com/azat)).
+* Fix crash in `SELECT count(notNullIn(NULL, []))`. [#10920](https://github.com/ClickHouse/ClickHouse/pull/10920) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix for the hang which was happening sometimes during DROP of table engine=Kafka (or during server restarts). [#10910](https://github.com/ClickHouse/ClickHouse/pull/10910) ([filimonov](https://github.com/filimonov)).
+* Now it's possible to execute multiple `ALTER RENAME` like `a TO b, c TO a`. [#10895](https://github.com/ClickHouse/ClickHouse/pull/10895) ([alesapin](https://github.com/alesapin)).
+* Fix possible race which could happen when you get result from aggregate function state from multiple thread for the same column. The only way (which I found) it can happen is when you use `finalizeAggregation` function while reading from table with `Memory` engine which stores `AggregateFunction` state for `quanite*` function. [#10890](https://github.com/ClickHouse/ClickHouse/pull/10890) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix backward compatibility with tuples in Distributed tables. [#10889](https://github.com/ClickHouse/ClickHouse/pull/10889) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix SIGSEGV in StringHashTable (if such key does not exist). [#10870](https://github.com/ClickHouse/ClickHouse/pull/10870) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed `WATCH` hangs after `LiveView` table was dropped from database with `Atomic` engine. [#10859](https://github.com/ClickHouse/ClickHouse/pull/10859) ([tavplubix](https://github.com/tavplubix)).
+* Fixed bug in `ReplicatedMergeTree` which might cause some `ALTER` on `OPTIMIZE` query to hang waiting for some replica after it become inactive. [#10849](https://github.com/ClickHouse/ClickHouse/pull/10849) ([tavplubix](https://github.com/tavplubix)).
+* Now constraints are updated if the column participating in `CONSTRAINT` expression was renamed. Fixes [#10844](https://github.com/ClickHouse/ClickHouse/issues/10844). [#10847](https://github.com/ClickHouse/ClickHouse/pull/10847) ([alesapin](https://github.com/alesapin)).
+* Fix potential read of uninitialized memory in cache dictionary. [#10834](https://github.com/ClickHouse/ClickHouse/pull/10834) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix columns order after Block::sortColumns() (also add a test that shows that it affects some real use case - Buffer engine). [#10826](https://github.com/ClickHouse/ClickHouse/pull/10826) ([Azat Khuzhin](https://github.com/azat)).
+* Fix the issue with ODBC bridge when no quoting of identifiers is requested. This fixes [#7984](https://github.com/ClickHouse/ClickHouse/issues/7984). [#10821](https://github.com/ClickHouse/ClickHouse/pull/10821) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix UBSan and MSan report in DateLUT. [#10798](https://github.com/ClickHouse/ClickHouse/pull/10798) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make use of `src_type` for correct type conversion in key conditions. Fixes [#6287](https://github.com/ClickHouse/ClickHouse/issues/6287). [#10791](https://github.com/ClickHouse/ClickHouse/pull/10791) ([Andrew Onyshchuk](https://github.com/oandrew)).
+* Get rid of old libunwind patches. https://github.com/ClickHouse-Extras/libunwind/commit/500aa227911bd185a94bfc071d68f4d3b03cb3b1#r39048012 This allows to disable `-fno-omit-frame-pointer` in `clang` builds that improves performance at least by 1% in average. [#10761](https://github.com/ClickHouse/ClickHouse/pull/10761) ([Amos Bird](https://github.com/amosbird)).
+* Fix avgWeighted when using floating-point weight over multiple shards. [#10758](https://github.com/ClickHouse/ClickHouse/pull/10758) ([Baudouin Giard](https://github.com/bgiard)).
+* Fix `parallel_view_processing` behavior. Now all insertions into `MATERIALIZED VIEW` without exception should be finished if exception happened. Fixes [#10241](https://github.com/ClickHouse/ClickHouse/issues/10241). [#10757](https://github.com/ClickHouse/ClickHouse/pull/10757) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix combinator -OrNull and -OrDefault when combined with -State. [#10741](https://github.com/ClickHouse/ClickHouse/pull/10741) ([hcz](https://github.com/hczhcz)).
+* Fix crash in `generateRandom` with nested types. Fixes [#10583](https://github.com/ClickHouse/ClickHouse/issues/10583). [#10734](https://github.com/ClickHouse/ClickHouse/pull/10734) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix data corruption for `LowCardinality(FixedString)` key column in `SummingMergeTree` which could have happened after merge. Fixes [#10489](https://github.com/ClickHouse/ClickHouse/issues/10489). [#10721](https://github.com/ClickHouse/ClickHouse/pull/10721) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix usage of primary key wrapped into a function with 'FINAL' modifier and 'ORDER BY' optimization. [#10715](https://github.com/ClickHouse/ClickHouse/pull/10715) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix possible buffer overflow in function `h3EdgeAngle`. [#10711](https://github.com/ClickHouse/ClickHouse/pull/10711) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix disappearing totals. Totals could have being filtered if query had had join or subquery with external where condition. Fixes [#10674](https://github.com/ClickHouse/ClickHouse/issues/10674). [#10698](https://github.com/ClickHouse/ClickHouse/pull/10698) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix atomicity of HTTP insert. This fixes [#9666](https://github.com/ClickHouse/ClickHouse/issues/9666). [#10687](https://github.com/ClickHouse/ClickHouse/pull/10687) ([Andrew Onyshchuk](https://github.com/oandrew)).
+* Fix multiple usages of `IN` operator with the identical set in one query. [#10686](https://github.com/ClickHouse/ClickHouse/pull/10686) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed bug, which causes http requests stuck on client close when `readonly=2` and `cancel_http_readonly_queries_on_client_close=1`. Fixes [#7939](https://github.com/ClickHouse/ClickHouse/issues/7939), [#7019](https://github.com/ClickHouse/ClickHouse/issues/7019), [#7736](https://github.com/ClickHouse/ClickHouse/issues/7736), [#7091](https://github.com/ClickHouse/ClickHouse/issues/7091). [#10684](https://github.com/ClickHouse/ClickHouse/pull/10684) ([tavplubix](https://github.com/tavplubix)).
+* Fix order of parameters in AggregateTransform constructor. [#10667](https://github.com/ClickHouse/ClickHouse/pull/10667) ([palasonic1](https://github.com/palasonic1)).
+* Fix the lack of parallel execution of remote queries with `distributed_aggregation_memory_efficient` enabled. Fixes [#10655](https://github.com/ClickHouse/ClickHouse/issues/10655). [#10664](https://github.com/ClickHouse/ClickHouse/pull/10664) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix possible incorrect number of rows for queries with `LIMIT`. Fixes [#10566](https://github.com/ClickHouse/ClickHouse/issues/10566), [#10709](https://github.com/ClickHouse/ClickHouse/issues/10709). [#10660](https://github.com/ClickHouse/ClickHouse/pull/10660) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug which locks concurrent alters when table has a lot of parts. [#10659](https://github.com/ClickHouse/ClickHouse/pull/10659) ([alesapin](https://github.com/alesapin)).
+* Fix nullptr dereference in StorageBuffer if server was shutdown before table startup. [#10641](https://github.com/ClickHouse/ClickHouse/pull/10641) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix predicates optimization for distributed queries (`enable_optimize_predicate_expression=1`) for queries with `HAVING` section (i.e. when filtering on the server initiator is required), by preserving the order of expressions (and this is enough to fix), and also force aggregator use column names over indexes. Fixes: [#10613](https://github.com/ClickHouse/ClickHouse/issues/10613), [#11413](https://github.com/ClickHouse/ClickHouse/issues/11413). [#10621](https://github.com/ClickHouse/ClickHouse/pull/10621) ([Azat Khuzhin](https://github.com/azat)).
+* Fix optimize_skip_unused_shards with LowCardinality. [#10611](https://github.com/ClickHouse/ClickHouse/pull/10611) ([Azat Khuzhin](https://github.com/azat)).
+* Fix segfault in StorageBuffer when exception on server startup. Fixes [#10550](https://github.com/ClickHouse/ClickHouse/issues/10550). [#10609](https://github.com/ClickHouse/ClickHouse/pull/10609) ([tavplubix](https://github.com/tavplubix)).
+* On `SYSTEM DROP DNS CACHE` query also drop caches, which are used to check if user is allowed to connect from some IP addresses. [#10608](https://github.com/ClickHouse/ClickHouse/pull/10608) ([tavplubix](https://github.com/tavplubix)).
+* Fixed incorrect scalar results inside inner query of `MATERIALIZED VIEW` in case if this query contained dependent table. [#10603](https://github.com/ClickHouse/ClickHouse/pull/10603) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed handling condition variable for synchronous mutations. In some cases signals to that condition variable could be lost. [#10588](https://github.com/ClickHouse/ClickHouse/pull/10588) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fixes possible crash `createDictionary()` is called before `loadStoredObject()` has finished. [#10587](https://github.com/ClickHouse/ClickHouse/pull/10587) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix error `the BloomFilter false positive must be a double number between 0 and 1` [#10551](https://github.com/ClickHouse/ClickHouse/issues/10551). [#10569](https://github.com/ClickHouse/ClickHouse/pull/10569) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix SELECT of column ALIAS which default expression type different from column type. [#10563](https://github.com/ClickHouse/ClickHouse/pull/10563) ([Azat Khuzhin](https://github.com/azat)).
+* Implemented comparison between DateTime64 and String values (just like for DateTime). [#10560](https://github.com/ClickHouse/ClickHouse/pull/10560) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fix index corruption, which may occur in some cases after merge compact parts into another compact part. [#10531](https://github.com/ClickHouse/ClickHouse/pull/10531) ([Anton Popov](https://github.com/CurtizJ)).
+* Disable GROUP BY sharding_key optimization by default (`optimize_distributed_group_by_sharding_key` had been introduced and turned of by default, due to trickery of sharding_key analyzing, simple example is `if` in sharding key) and fix it for WITH ROLLUP/CUBE/TOTALS. [#10516](https://github.com/ClickHouse/ClickHouse/pull/10516) ([Azat Khuzhin](https://github.com/azat)).
+* Fixes: [#10263](https://github.com/ClickHouse/ClickHouse/issues/10263) (after that PR dist send via INSERT had been postponing on each INSERT) Fixes: [#8756](https://github.com/ClickHouse/ClickHouse/issues/8756) (that PR breaks distributed sends with all of the following conditions met (unlikely setup for now I guess): `internal_replication == false`, multiple local shards (activates the hardlinking code) and `distributed_storage_policy` (makes `link(2)` fails on `EXDEV`)). [#10486](https://github.com/ClickHouse/ClickHouse/pull/10486) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed error with "max_rows_to_sort" limit. [#10268](https://github.com/ClickHouse/ClickHouse/pull/10268) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Get dictionary and check access rights only once per each call of any function reading external dictionaries. [#10928](https://github.com/ClickHouse/ClickHouse/pull/10928) ([Vitaly Baranov](https://github.com/vitlibar)).
+
+#### Improvement
+
+* Apply `TTL` for old data, after `ALTER MODIFY TTL` query. This behaviour is controlled by setting `materialize_ttl_after_modify`, which is enabled by default. [#11042](https://github.com/ClickHouse/ClickHouse/pull/11042) ([Anton Popov](https://github.com/CurtizJ)).
+* When parsing C-style backslash escapes in string literals, VALUES and various text formats (this is an extension to SQL standard that is endemic for ClickHouse and MySQL), keep backslash if unknown escape sequence is found (e.g. `\%` or `\w`) that will make usage of `LIKE` and `match` regular expressions more convenient (it's enough to write `name LIKE 'used\_cars'` instead of `name LIKE 'used\\_cars'`) and more compatible at the same time. This fixes [#10922](https://github.com/ClickHouse/ClickHouse/issues/10922). [#11208](https://github.com/ClickHouse/ClickHouse/pull/11208) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* When reading Decimal value, cut extra digits after point. This behaviour is more compatible with MySQL and PostgreSQL. This fixes [#10202](https://github.com/ClickHouse/ClickHouse/issues/10202). [#11831](https://github.com/ClickHouse/ClickHouse/pull/11831) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow to DROP replicated table if the metadata in ZooKeeper was already removed and does not exist (this is also the case when using TestKeeper for testing and the server was restarted). Allow to RENAME replicated table even if there is an error communicating with ZooKeeper. This fixes [#10720](https://github.com/ClickHouse/ClickHouse/issues/10720). [#11652](https://github.com/ClickHouse/ClickHouse/pull/11652) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Slightly improve diagnostic of reading decimal from string. This closes [#10202](https://github.com/ClickHouse/ClickHouse/issues/10202). [#11829](https://github.com/ClickHouse/ClickHouse/pull/11829) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix sleep invocation in signal handler. It was sleeping for less amount of time than expected. [#11825](https://github.com/ClickHouse/ClickHouse/pull/11825) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* (Only Linux) OS related performance metrics (for CPU and I/O) will work even without `CAP_NET_ADMIN` capability. [#10544](https://github.com/ClickHouse/ClickHouse/pull/10544) ([Alexander Kazakov](https://github.com/Akazz)).
+* Added `hostname` as an alias to function `hostName`. This feature was suggested by Victor Tarnavskiy from Yandex.Metrica. [#11821](https://github.com/ClickHouse/ClickHouse/pull/11821) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added support for distributed `DDL` (update/delete/drop partition) on cross replication clusters. [#11703](https://github.com/ClickHouse/ClickHouse/pull/11703) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Emit warning instead of error in server log at startup if we cannot listen one of the listen addresses (e.g. IPv6 is unavailable inside Docker). Note that if server fails to listen all listed addresses, it will refuse to startup as before. This fixes [#4406](https://github.com/ClickHouse/ClickHouse/issues/4406). [#11687](https://github.com/ClickHouse/ClickHouse/pull/11687) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Default user and database creation on docker image starting. [#10637](https://github.com/ClickHouse/ClickHouse/pull/10637) ([Paramtamtam](https://github.com/tarampampam)).
+* When multiline query is printed to server log, the lines are joined. Make it to work correct in case of multiline string literals, identifiers and single-line comments. This fixes [#3853](https://github.com/ClickHouse/ClickHouse/issues/3853). [#11686](https://github.com/ClickHouse/ClickHouse/pull/11686) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Multiple names are now allowed in commands: CREATE USER, CREATE ROLE, ALTER USER, SHOW CREATE USER, SHOW GRANTS and so on. [#11670](https://github.com/ClickHouse/ClickHouse/pull/11670) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Add support for distributed DDL (`UPDATE/DELETE/DROP PARTITION`) on cross replication clusters. [#11508](https://github.com/ClickHouse/ClickHouse/pull/11508) ([frank lee](https://github.com/etah000)).
+* Clear password from command line in `clickhouse-client` and `clickhouse-benchmark` if the user has specified it with explicit value. This prevents password exposure by `ps` and similar tools. [#11665](https://github.com/ClickHouse/ClickHouse/pull/11665) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Don't use debug info from ELF file if it does not correspond to the running binary. It is needed to avoid printing wrong function names and source locations in stack traces. This fixes [#7514](https://github.com/ClickHouse/ClickHouse/issues/7514). [#11657](https://github.com/ClickHouse/ClickHouse/pull/11657) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Return NULL/zero when value is not parsed completely in parseDateTimeBestEffortOrNull/Zero functions. This fixes [#7876](https://github.com/ClickHouse/ClickHouse/issues/7876). [#11653](https://github.com/ClickHouse/ClickHouse/pull/11653) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Skip empty parameters in requested URL. They may appear when you write `http://localhost:8123/?&a=b` or `http://localhost:8123/?a=b&&c=d`. This closes [#10749](https://github.com/ClickHouse/ClickHouse/issues/10749). [#11651](https://github.com/ClickHouse/ClickHouse/pull/11651) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow using `groupArrayArray` and `groupUniqArrayArray` as `SimpleAggregateFunction`. [#11650](https://github.com/ClickHouse/ClickHouse/pull/11650) ([Volodymyr Kuznetsov](https://github.com/ksvladimir)).
+* Allow comparison with constant strings by implicit conversions when analysing index conditions on other types. This may close [#11630](https://github.com/ClickHouse/ClickHouse/issues/11630). [#11648](https://github.com/ClickHouse/ClickHouse/pull/11648) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* https://github.com/ClickHouse/ClickHouse/pull/7572#issuecomment-642815377 Support config default HTTPHandlers. [#11628](https://github.com/ClickHouse/ClickHouse/pull/11628) ([Winter Zhang](https://github.com/zhang2014)).
+* Make more input formats to work with Kafka engine. Fix the issue with premature flushes. Fix the performance issue when `kafka_num_consumers` is greater than number of partitions in topic. [#11599](https://github.com/ClickHouse/ClickHouse/pull/11599) ([filimonov](https://github.com/filimonov)).
+* Improve `multiple_joins_rewriter_version=2` logic. Fix unknown columns error for lambda aliases. [#11587](https://github.com/ClickHouse/ClickHouse/pull/11587) ([Artem Zuikov](https://github.com/4ertus2)).
+* Better exception message when cannot parse columns declaration list. This closes [#10403](https://github.com/ClickHouse/ClickHouse/issues/10403). [#11537](https://github.com/ClickHouse/ClickHouse/pull/11537) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve `enable_optimize_predicate_expression=1` logic for VIEW. [#11513](https://github.com/ClickHouse/ClickHouse/pull/11513) ([Artem Zuikov](https://github.com/4ertus2)).
+* Adding support for PREWHERE in live view tables. [#11495](https://github.com/ClickHouse/ClickHouse/pull/11495) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Automatically update DNS cache, which is used to check if user is allowed to connect from an address. [#11487](https://github.com/ClickHouse/ClickHouse/pull/11487) ([tavplubix](https://github.com/tavplubix)).
+* OPTIMIZE FINAL will force merge even if concurrent merges are performed. This closes [#11309](https://github.com/ClickHouse/ClickHouse/issues/11309) and closes [#11322](https://github.com/ClickHouse/ClickHouse/issues/11322). [#11346](https://github.com/ClickHouse/ClickHouse/pull/11346) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Suppress output of cancelled queries in clickhouse-client. In previous versions result may continue to print in terminal even after you press Ctrl+C to cancel query. This closes [#9473](https://github.com/ClickHouse/ClickHouse/issues/9473). [#11342](https://github.com/ClickHouse/ClickHouse/pull/11342) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now history file is updated after each query and there is no race condition if multiple clients use one history file. This fixes [#9897](https://github.com/ClickHouse/ClickHouse/issues/9897). [#11453](https://github.com/ClickHouse/ClickHouse/pull/11453) ([Tagir Kuskarov](https://github.com/kuskarov)).
+* Better log messages in while reloading configuration. [#11341](https://github.com/ClickHouse/ClickHouse/pull/11341) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove trailing whitespaces from formatted queries in `clickhouse-client` or `clickhouse-format` in some cases. [#11325](https://github.com/ClickHouse/ClickHouse/pull/11325) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add setting "output_format_pretty_max_value_width". If value is longer, it will be cut to avoid output of too large values in terminal. This closes [#11140](https://github.com/ClickHouse/ClickHouse/issues/11140). [#11324](https://github.com/ClickHouse/ClickHouse/pull/11324) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Better exception message in case when there is shortage of memory mappings. This closes [#11027](https://github.com/ClickHouse/ClickHouse/issues/11027). [#11316](https://github.com/ClickHouse/ClickHouse/pull/11316) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support (U)Int8, (U)Int16, Date in ASOF JOIN. [#11301](https://github.com/ClickHouse/ClickHouse/pull/11301) ([Artem Zuikov](https://github.com/4ertus2)).
+* Support kafka_client_id parameter for Kafka tables. It also changes the default `client.id` used by ClickHouse when communicating with Kafka to be more verbose and usable. [#11252](https://github.com/ClickHouse/ClickHouse/pull/11252) ([filimonov](https://github.com/filimonov)).
+* Keep the value of `DistributedFilesToInsert` metric on exceptions. In previous versions, the value was set when we are going to send some files, but it is zero, if there was an exception and some files are still pending. Now it corresponds to the number of pending files in filesystem. [#11220](https://github.com/ClickHouse/ClickHouse/pull/11220) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add support for multi-word data type names (such as `DOUBLE PRECISION` and `CHAR VARYING`) for better SQL compatibility. [#11214](https://github.com/ClickHouse/ClickHouse/pull/11214) ([Павел Потемкин](https://github.com/Potya)).
+* Provide synonyms for some data types. [#10856](https://github.com/ClickHouse/ClickHouse/pull/10856) ([Павел Потемкин](https://github.com/Potya)).
+* The query log is now enabled by default. [#11184](https://github.com/ClickHouse/ClickHouse/pull/11184) ([Ivan Blinkov](https://github.com/blinkov)).
+* Show authentication type in table system.users and while executing SHOW CREATE USER query. [#11080](https://github.com/ClickHouse/ClickHouse/pull/11080) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Remove data on explicit `DROP DATABASE` for `Memory` database engine. Fixes [#10557](https://github.com/ClickHouse/ClickHouse/issues/10557). [#11021](https://github.com/ClickHouse/ClickHouse/pull/11021) ([tavplubix](https://github.com/tavplubix)).
+* Set thread names for internal threads of rdkafka library. Make logs from rdkafka available in server logs. [#10983](https://github.com/ClickHouse/ClickHouse/pull/10983) ([Azat Khuzhin](https://github.com/azat)).
+* Support for unicode whitespaces in queries. This helps when queries are copy-pasted from Word or from web page. This fixes [#10896](https://github.com/ClickHouse/ClickHouse/issues/10896). [#10903](https://github.com/ClickHouse/ClickHouse/pull/10903) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow large UInt types as the index in function `tupleElement`. [#10874](https://github.com/ClickHouse/ClickHouse/pull/10874) ([hcz](https://github.com/hczhcz)).
+* Respect prefer_localhost_replica/load_balancing on INSERT into Distributed. [#10867](https://github.com/ClickHouse/ClickHouse/pull/10867) ([Azat Khuzhin](https://github.com/azat)).
+* Introduce `min_insert_block_size_rows_for_materialized_views`, `min_insert_block_size_bytes_for_materialized_views` settings. This settings are similar to `min_insert_block_size_rows` and `min_insert_block_size_bytes`, but applied only for blocks inserted into `MATERIALIZED VIEW`. It helps to control blocks squashing while pushing to MVs and avoid excessive memory usage. [#10858](https://github.com/ClickHouse/ClickHouse/pull/10858) ([Azat Khuzhin](https://github.com/azat)).
+* Get rid of exception from replicated queue during server shutdown. Fixes [#10819](https://github.com/ClickHouse/ClickHouse/issues/10819). [#10841](https://github.com/ClickHouse/ClickHouse/pull/10841) ([alesapin](https://github.com/alesapin)).
+* Ensure that `varSamp`, `varPop` cannot return negative results due to numerical errors and that `stddevSamp`, `stddevPop` cannot be calculated from negative variance. This fixes [#10532](https://github.com/ClickHouse/ClickHouse/issues/10532). [#10829](https://github.com/ClickHouse/ClickHouse/pull/10829) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Better DNS exception message. This fixes [#10813](https://github.com/ClickHouse/ClickHouse/issues/10813). [#10828](https://github.com/ClickHouse/ClickHouse/pull/10828) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Change HTTP response code in case of some parse errors to 400 Bad Request. This fix [#10636](https://github.com/ClickHouse/ClickHouse/issues/10636). [#10640](https://github.com/ClickHouse/ClickHouse/pull/10640) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Print a message if clickhouse-client is newer than clickhouse-server. [#10627](https://github.com/ClickHouse/ClickHouse/pull/10627) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Adding support for `INSERT INTO [db.]table WATCH` query. [#10498](https://github.com/ClickHouse/ClickHouse/pull/10498) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Allow to pass quota_key in clickhouse-client. This closes [#10227](https://github.com/ClickHouse/ClickHouse/issues/10227). [#10270](https://github.com/ClickHouse/ClickHouse/pull/10270) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### Performance Improvement
+
+* Allow multiple replicas to assign merges, mutations, partition drop, move and replace concurrently. This closes [#10367](https://github.com/ClickHouse/ClickHouse/issues/10367). [#11639](https://github.com/ClickHouse/ClickHouse/pull/11639) ([alexey-milovidov](https://github.com/alexey-milovidov)) [#11795](https://github.com/ClickHouse/ClickHouse/pull/11795) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Optimization of GROUP BY with respect to table sorting key, enabled with `optimize_aggregation_in_order` setting. [#9113](https://github.com/ClickHouse/ClickHouse/pull/9113) ([dimarub2000](https://github.com/dimarub2000)).
+* Selects with final are executed in parallel. Added setting `max_final_threads` to limit the number of threads used. [#10463](https://github.com/ClickHouse/ClickHouse/pull/10463) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Improve performance for INSERT queries via `INSERT SELECT` or INSERT with clickhouse-client when small blocks are generated (typical case with parallel parsing). This fixes [#11275](https://github.com/ClickHouse/ClickHouse/issues/11275). Fix the issue that CONSTRAINTs were not working for DEFAULT fields. This fixes [#11273](https://github.com/ClickHouse/ClickHouse/issues/11273). Fix the issue that CONSTRAINTS were ignored for TEMPORARY tables. This fixes [#11274](https://github.com/ClickHouse/ClickHouse/issues/11274). [#11276](https://github.com/ClickHouse/ClickHouse/pull/11276) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Optimization that eliminates min/max/any aggregators of GROUP BY keys in SELECT section, enabled with `optimize_aggregators_of_group_by_keys` setting. [#11667](https://github.com/ClickHouse/ClickHouse/pull/11667) ([xPoSx](https://github.com/xPoSx)). [#11806](https://github.com/ClickHouse/ClickHouse/pull/11806) ([Azat Khuzhin](https://github.com/azat)).
+* New optimization that takes all operations out of `any` function, enabled with `optimize_move_functions_out_of_any` [#11529](https://github.com/ClickHouse/ClickHouse/pull/11529) ([Ruslan](https://github.com/kamalov-ruslan)).
+* Improve performance of `clickhouse-client` in interactive mode when Pretty formats are used. In previous versions, significant amount of time can be spent calculating visible width of UTF-8 string. This closes [#11323](https://github.com/ClickHouse/ClickHouse/issues/11323). [#11323](https://github.com/ClickHouse/ClickHouse/pull/11323) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improved performance for queries with `ORDER BY` and small `LIMIT` (less, then `max_block_size`). [#11171](https://github.com/ClickHouse/ClickHouse/pull/11171) ([Albert Kidrachev](https://github.com/Provet)).
+* Add runtime CPU detection to select and dispatch the best function implementation. Add support for codegeneration for multiple targets. This closes [#1017](https://github.com/ClickHouse/ClickHouse/issues/1017). [#10058](https://github.com/ClickHouse/ClickHouse/pull/10058) ([DimasKovas](https://github.com/DimasKovas)).
+* Enable `mlock` of clickhouse binary by default. It will prevent clickhouse executable from being paged out under high IO load. [#11139](https://github.com/ClickHouse/ClickHouse/pull/11139) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make queries with `sum` aggregate function and without GROUP BY keys to run multiple times faster. [#10992](https://github.com/ClickHouse/ClickHouse/pull/10992) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improving radix sort (used in `ORDER BY` with simple keys) by removing some redundant data moves. [#10981](https://github.com/ClickHouse/ClickHouse/pull/10981) ([Arslan Gumerov](https://github.com/g-arslan)).
+* Sort bigger parts of the left table in MergeJoin. Buffer left blocks in memory. Add `partial_merge_join_left_table_buffer_bytes` setting to manage the left blocks buffers sizes. [#10601](https://github.com/ClickHouse/ClickHouse/pull/10601) ([Artem Zuikov](https://github.com/4ertus2)).
+* Remove duplicate ORDER BY and DISTINCT from subqueries, this optimization is enabled with `optimize_duplicate_order_by_and_distinct` [#10067](https://github.com/ClickHouse/ClickHouse/pull/10067) ([Mikhail Malafeev](https://github.com/demo-99)).
+* This feature eliminates functions of other keys in GROUP BY section, enabled with `optimize_group_by_function_keys` [#10051](https://github.com/ClickHouse/ClickHouse/pull/10051) ([xPoSx](https://github.com/xPoSx)).
+* New optimization that takes arithmetic operations out of aggregate functions, enabled with `optimize_arithmetic_operations_in_aggregate_functions` [#10047](https://github.com/ClickHouse/ClickHouse/pull/10047) ([Ruslan](https://github.com/kamalov-ruslan)).
+* Use HTTP client for S3 based on Poco instead of curl. This will improve performance and lower memory usage of s3 storage and table functions. [#11230](https://github.com/ClickHouse/ClickHouse/pull/11230) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fix Kafka performance issue related to reschedules based on limits, which were always applied. [#11149](https://github.com/ClickHouse/ClickHouse/pull/11149) ([filimonov](https://github.com/filimonov)).
+* Enable percpu_arena:percpu for jemalloc (This will reduce memory fragmentation due to thread pool). [#11084](https://github.com/ClickHouse/ClickHouse/pull/11084) ([Azat Khuzhin](https://github.com/azat)).
+* Optimize memory usage when reading a response from an S3 HTTP client. [#11561](https://github.com/ClickHouse/ClickHouse/pull/11561) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Adjust the default Kafka settings for better performance. [#11388](https://github.com/ClickHouse/ClickHouse/pull/11388) ([filimonov](https://github.com/filimonov)).
+
+#### Experimental Feature
+
+* Add data type `Point` (Tuple(Float64, Float64)) and `Polygon` (Array(Array(Tuple(Float64, Float64))). [#10678](https://github.com/ClickHouse/ClickHouse/pull/10678) ([Alexey Ilyukhov](https://github.com/livace)).
+* Add's a `hasSubstr` function that allows for look for subsequences in arrays. Note: this function is likely to be renamed without further notice. [#11071](https://github.com/ClickHouse/ClickHouse/pull/11071) ([Ryad Zenine](https://github.com/r-zenine)).
+* Added OpenCL support and bitonic sort algorithm, which can be used for sorting integer types of data in single column. Needs to be build with flag `-DENABLE_OPENCL=1`. For using bitonic sort algorithm instead of others you need to set `bitonic_sort` for Setting's option `special_sort` and make sure that OpenCL is available. This feature does not improve performance or anything else, it is only provided as an example and for demonstration purposes. It is likely to be removed in near future if there will be no further development in this direction. [#10232](https://github.com/ClickHouse/ClickHouse/pull/10232) ([Ri](https://github.com/margaritiko)).
+
+#### Build/Testing/Packaging Improvement
+
+* Enable clang-tidy for programs and utils. [#10991](https://github.com/ClickHouse/ClickHouse/pull/10991) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove dependency on `tzdata`: do not fail if `/usr/share/zoneinfo` directory does not exist. Note that all timezones work in ClickHouse even without tzdata installed in system. [#11827](https://github.com/ClickHouse/ClickHouse/pull/11827) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added MSan and UBSan stress tests. Note that we already have MSan, UBSan for functional tests and "stress" test is another kind of tests. [#10871](https://github.com/ClickHouse/ClickHouse/pull/10871) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Print compiler build id in crash messages. It will make us slightly more certain about what binary has crashed. Added new function `buildId`. [#11824](https://github.com/ClickHouse/ClickHouse/pull/11824) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added a test to ensure that mutations continue to work after FREEZE query. [#11820](https://github.com/ClickHouse/ClickHouse/pull/11820) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Don't allow tests with "fail" substring in their names because it makes looking at the tests results in browser less convenient when you type Ctrl+F and search for "fail". [#11817](https://github.com/ClickHouse/ClickHouse/pull/11817) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Removes unused imports from HTTPHandlerFactory. [#11660](https://github.com/ClickHouse/ClickHouse/pull/11660) ([Bharat Nallan](https://github.com/bharatnc)).
+* Added a random sampling of instances where copier is executed. It is needed to avoid `Too many simultaneous queries` error. Also increased timeout and decreased fault probability. [#11573](https://github.com/ClickHouse/ClickHouse/pull/11573) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix missed include. [#11525](https://github.com/ClickHouse/ClickHouse/pull/11525) ([Matwey V. Kornilov](https://github.com/matwey)).
+* Speed up build by removing old example programs. Also found some orphan functional test. [#11486](https://github.com/ClickHouse/ClickHouse/pull/11486) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Increase ccache size for builds in CI. [#11450](https://github.com/ClickHouse/ClickHouse/pull/11450) ([alesapin](https://github.com/alesapin)).
+* Leave only unit_tests_dbms in deb build. [#11429](https://github.com/ClickHouse/ClickHouse/pull/11429) ([Ilya Yatsishin](https://github.com/qoega)).
+* Update librdkafka to version [1.4.2](https://github.com/edenhill/librdkafka/releases/tag/v1.4.2). [#11256](https://github.com/ClickHouse/ClickHouse/pull/11256) ([filimonov](https://github.com/filimonov)).
+* Refactor CMake build files. [#11390](https://github.com/ClickHouse/ClickHouse/pull/11390) ([Ivan](https://github.com/abyss7)).
+* Fix several flaky integration tests. [#11355](https://github.com/ClickHouse/ClickHouse/pull/11355) ([alesapin](https://github.com/alesapin)).
+* Add support for unit tests run with UBSan. [#11345](https://github.com/ClickHouse/ClickHouse/pull/11345) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove redundant timeout from integration test `test_insertion_sync_fails_with_timeout`. [#11343](https://github.com/ClickHouse/ClickHouse/pull/11343) ([alesapin](https://github.com/alesapin)).
+* Better check for hung queries in clickhouse-test. [#11321](https://github.com/ClickHouse/ClickHouse/pull/11321) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Emit a warning if server was build in debug or with sanitizers. [#11304](https://github.com/ClickHouse/ClickHouse/pull/11304) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now clickhouse-test check the server aliveness before tests run. [#11285](https://github.com/ClickHouse/ClickHouse/pull/11285) ([alesapin](https://github.com/alesapin)).
+* Fix potentially flacky test `00731_long_merge_tree_select_opened_files.sh`. It does not fail frequently but we have discovered potential race condition in this test while experimenting with ThreadFuzzer: [#9814](https://github.com/ClickHouse/ClickHouse/issues/9814) See [link](https://clickhouse-test-reports.s3.yandex.net/9814/40e3023e215df22985d275bf85f4d2290897b76b/functional_stateless_tests_(unbundled).html#fail1) for the example. [#11270](https://github.com/ClickHouse/ClickHouse/pull/11270) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Repeat test in CI if `curl` invocation was timed out. It is possible due to system hangups for 10+ seconds that are typical in our CI infrastructure. This fixes [#11267](https://github.com/ClickHouse/ClickHouse/issues/11267). [#11268](https://github.com/ClickHouse/ClickHouse/pull/11268) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add a test for Join table engine from @donmikel. This closes [#9158](https://github.com/ClickHouse/ClickHouse/issues/9158). [#11265](https://github.com/ClickHouse/ClickHouse/pull/11265) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix several non significant errors in unit tests. [#11262](https://github.com/ClickHouse/ClickHouse/pull/11262) ([alesapin](https://github.com/alesapin)).
+* Now parts of linker command for `cctz` library will not be shuffled with other libraries. [#11213](https://github.com/ClickHouse/ClickHouse/pull/11213) ([alesapin](https://github.com/alesapin)).
+* Split /programs/server into actual program and library. [#11186](https://github.com/ClickHouse/ClickHouse/pull/11186) ([Ivan](https://github.com/abyss7)).
+* Improve build scripts for protobuf & gRPC. [#11172](https://github.com/ClickHouse/ClickHouse/pull/11172) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Enable performance test that was not working. [#11158](https://github.com/ClickHouse/ClickHouse/pull/11158) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Create root S3 bucket for tests before any CH instance is started. [#11142](https://github.com/ClickHouse/ClickHouse/pull/11142) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Add performance test for non-constant polygons. [#11141](https://github.com/ClickHouse/ClickHouse/pull/11141) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixing `00979_live_view_watch_continuous_aggregates` test. [#11024](https://github.com/ClickHouse/ClickHouse/pull/11024) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Add ability to run zookeeper in integration tests over tmpfs. [#11002](https://github.com/ClickHouse/ClickHouse/pull/11002) ([alesapin](https://github.com/alesapin)).
+* Wait for odbc-bridge with exponential backoff. Previous wait time of 200 ms was not enough in our CI environment. [#10990](https://github.com/ClickHouse/ClickHouse/pull/10990) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix non-deterministic test. [#10989](https://github.com/ClickHouse/ClickHouse/pull/10989) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added a test for empty external data. [#10926](https://github.com/ClickHouse/ClickHouse/pull/10926) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Database is recreated for every test. This improves separation of tests. [#10902](https://github.com/ClickHouse/ClickHouse/pull/10902) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added more asserts in columns code. [#10833](https://github.com/ClickHouse/ClickHouse/pull/10833) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Better cooperation with sanitizers. Print information about query_id in the message of sanitizer failure. [#10832](https://github.com/ClickHouse/ClickHouse/pull/10832) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix obvious race condition in "Split build smoke test" check. [#10820](https://github.com/ClickHouse/ClickHouse/pull/10820) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix (false) MSan report in MergeTreeIndexFullText. The issue first appeared in [#9968](https://github.com/ClickHouse/ClickHouse/issues/9968). [#10801](https://github.com/ClickHouse/ClickHouse/pull/10801) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add MSan suppression for MariaDB Client library. [#10800](https://github.com/ClickHouse/ClickHouse/pull/10800) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* GRPC make couldn't find protobuf files, changed make file by adding the right link. [#10794](https://github.com/ClickHouse/ClickHouse/pull/10794) ([mnkonkova](https://github.com/mnkonkova)).
+* Enable extra warnings (`-Weverything`) for base, utils, programs. Note that we already have it for the most of the code. [#10779](https://github.com/ClickHouse/ClickHouse/pull/10779) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Suppressions of warnings from libraries was mistakenly declared as public in [#10396](https://github.com/ClickHouse/ClickHouse/issues/10396). [#10776](https://github.com/ClickHouse/ClickHouse/pull/10776) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Restore a patch that was accidentially deleted in [#10396](https://github.com/ClickHouse/ClickHouse/issues/10396). [#10774](https://github.com/ClickHouse/ClickHouse/pull/10774) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix performance tests errors, part 2. [#10773](https://github.com/ClickHouse/ClickHouse/pull/10773) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix performance test errors. [#10766](https://github.com/ClickHouse/ClickHouse/pull/10766) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Update cross-builds to use clang-10 compiler. [#10724](https://github.com/ClickHouse/ClickHouse/pull/10724) ([Ivan](https://github.com/abyss7)).
+* Update instruction to install RPM packages. This was suggested by Denis (TG login @ldviolet) and implemented by Arkady Shejn. [#10707](https://github.com/ClickHouse/ClickHouse/pull/10707) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Trying to fix `tests/queries/0_stateless/01246_insert_into_watch_live_view.py` test. [#10670](https://github.com/ClickHouse/ClickHouse/pull/10670) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Fixing and re-enabling 00979_live_view_watch_continuous_aggregates.py test. [#10658](https://github.com/ClickHouse/ClickHouse/pull/10658) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Fix OOM in ASan stress test. [#10646](https://github.com/ClickHouse/ClickHouse/pull/10646) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix UBSan report (adding zero to nullptr) in HashTable that appeared after migration to clang-10. [#10638](https://github.com/ClickHouse/ClickHouse/pull/10638) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove external call to `ld` (bfd) linker during tzdata processing in compile time. [#10634](https://github.com/ClickHouse/ClickHouse/pull/10634) ([alesapin](https://github.com/alesapin)).
+* Allow to use `lld` to link blobs (resources). [#10632](https://github.com/ClickHouse/ClickHouse/pull/10632) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix UBSan report in `LZ4` library. [#10631](https://github.com/ClickHouse/ClickHouse/pull/10631) ([alexey-milovidov](https://github.com/alexey-milovidov)). See also [https://github.com/lz4/lz4/issues/857](https://github.com/lz4/lz4/issues/857)
+* Update LZ4 to the latest dev branch. [#10630](https://github.com/ClickHouse/ClickHouse/pull/10630) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added auto-generated machine-readable file with the list of stable versions. [#10628](https://github.com/ClickHouse/ClickHouse/pull/10628) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `capnproto` version check for `capnp::UnalignedFlatArrayMessageReader`. [#10618](https://github.com/ClickHouse/ClickHouse/pull/10618) ([Matwey V. Kornilov](https://github.com/matwey)).
+* Lower memory usage in tests. [#10617](https://github.com/ClickHouse/ClickHouse/pull/10617) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixing hard coded timeouts in new live view tests. [#10604](https://github.com/ClickHouse/ClickHouse/pull/10604) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Increasing timeout when opening a client in tests/queries/0_stateless/helpers/client.py. [#10599](https://github.com/ClickHouse/ClickHouse/pull/10599) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Enable ThinLTO for clang builds, continuation of [#10435](https://github.com/ClickHouse/ClickHouse/pull/10435). [#10585](https://github.com/ClickHouse/ClickHouse/pull/10585) ([Amos Bird](https://github.com/amosbird)).
+* Adding fuzzers and preparing for oss-fuzz integration. [#10546](https://github.com/ClickHouse/ClickHouse/pull/10546) ([kyprizel](https://github.com/kyprizel)).
+* Fix FreeBSD build. [#10150](https://github.com/ClickHouse/ClickHouse/pull/10150) ([Ivan](https://github.com/abyss7)).
+* Add new build for query tests using pytest framework. [#10039](https://github.com/ClickHouse/ClickHouse/pull/10039) ([Ivan](https://github.com/abyss7)).
+
+
+## ClickHouse release v20.4
+
+### ClickHouse release v20.4.8.99-stable 2020-08-10
+
+#### Bug Fix
+
+* Fixed error in `parseDateTimeBestEffort` function when unix timestamp was passed as an argument. This fixes [#13362](https://github.com/ClickHouse/ClickHouse/issues/13362). [#13441](https://github.com/ClickHouse/ClickHouse/pull/13441) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potentially low performance and slightly incorrect result for `uniqExact`, `topK`, `sumDistinct` and similar aggregate functions called on Float types with NaN values. It also triggered assert in debug build. This fixes [#12491](https://github.com/ClickHouse/ClickHouse/issues/12491). [#13254](https://github.com/ClickHouse/ClickHouse/pull/13254) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed function if with nullable constexpr as cond that is not literal NULL. Fixes [#12463](https://github.com/ClickHouse/ClickHouse/issues/12463). [#13226](https://github.com/ClickHouse/ClickHouse/pull/13226) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed assert in `arrayElement` function in case of array elements are Nullable and array subscript is also Nullable. This fixes [#12172](https://github.com/ClickHouse/ClickHouse/issues/12172). [#13224](https://github.com/ClickHouse/ClickHouse/pull/13224) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed wrong index analysis with functions. It could lead to pruning wrong parts, while reading from `MergeTree` tables. Fixes [#13060](https://github.com/ClickHouse/ClickHouse/issues/13060). Fixes [#12406](https://github.com/ClickHouse/ClickHouse/issues/12406). [#13081](https://github.com/ClickHouse/ClickHouse/pull/13081) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed unnecessary limiting for the number of threads for selects from local replica. [#12840](https://github.com/ClickHouse/ClickHouse/pull/12840) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed possible extra overflow row in data which could appear for queries `WITH TOTALS`. [#12747](https://github.com/ClickHouse/ClickHouse/pull/12747) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed performance with large tuples, which are interpreted as functions in `IN` section. The case when user write `WHERE x IN tuple(1, 2, ...)` instead of `WHERE x IN (1, 2, ...)` for some obscure reason. [#12700](https://github.com/ClickHouse/ClickHouse/pull/12700) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed memory tracking for `input_format_parallel_parsing` (by attaching thread to group). [#12672](https://github.com/ClickHouse/ClickHouse/pull/12672) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed [#12293](https://github.com/ClickHouse/ClickHouse/issues/12293) allow push predicate when subquery contains with clause. [#12663](https://github.com/ClickHouse/ClickHouse/pull/12663) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed [#10572](https://github.com/ClickHouse/ClickHouse/issues/10572) fix bloom filter index with const expression. [#12659](https://github.com/ClickHouse/ClickHouse/pull/12659) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed `SIGSEGV` in `StorageKafka` when broker is unavailable (and not only). [#12658](https://github.com/ClickHouse/ClickHouse/pull/12658) ([Azat Khuzhin](https://github.com/azat)).
+* Added support for function `if` with `Array(UUID)` arguments. This fixes [#11066](https://github.com/ClickHouse/ClickHouse/issues/11066). [#12648](https://github.com/ClickHouse/ClickHouse/pull/12648) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed race condition in external dictionaries with cache layout which can lead server crash. [#12566](https://github.com/ClickHouse/ClickHouse/pull/12566) ([alesapin](https://github.com/alesapin)).
+* Removed data for Distributed tables (blocks from async INSERTs) on DROP TABLE. [#12556](https://github.com/ClickHouse/ClickHouse/pull/12556) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed bug which lead to broken old parts after `ALTER DELETE` query when `enable_mixed_granularity_parts=1`. Fixes [#12536](https://github.com/ClickHouse/ClickHouse/issues/12536). [#12543](https://github.com/ClickHouse/ClickHouse/pull/12543) ([alesapin](https://github.com/alesapin)).
+* Better exception for function `in` with invalid number of arguments. [#12529](https://github.com/ClickHouse/ClickHouse/pull/12529) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed performance issue, while reading from compact parts. [#12492](https://github.com/ClickHouse/ClickHouse/pull/12492) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed crash in JOIN with dictionary when we are joining over expression of dictionary key: `t JOIN dict ON expr(dict.id) = t.id`. Disable dictionary join optimisation for this case. [#12458](https://github.com/ClickHouse/ClickHouse/pull/12458) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixed possible segfault if StorageMerge. Closes [#12054](https://github.com/ClickHouse/ClickHouse/issues/12054). [#12401](https://github.com/ClickHouse/ClickHouse/pull/12401) ([tavplubix](https://github.com/tavplubix)).
+* Fixed order of columns in `WITH FILL` modifier. Previously order of columns of `ORDER BY` statement wasn't respected. [#12306](https://github.com/ClickHouse/ClickHouse/pull/12306) ([Anton Popov](https://github.com/CurtizJ)).
+* Avoid "bad cast" exception when there is an expression that filters data by virtual columns (like `_table` in `Merge` tables) or by "index" columns in system tables such as filtering by database name when querying from `system.tables`, and this expression returns `Nullable` type. This fixes [#12166](https://github.com/ClickHouse/ClickHouse/issues/12166). [#12305](https://github.com/ClickHouse/ClickHouse/pull/12305) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Show error after TrieDictionary failed to load. [#12290](https://github.com/ClickHouse/ClickHouse/pull/12290) ([Vitaly Baranov](https://github.com/vitlibar)).
+* The function `arrayFill` worked incorrectly for empty arrays that may lead to crash. This fixes [#12263](https://github.com/ClickHouse/ClickHouse/issues/12263). [#12279](https://github.com/ClickHouse/ClickHouse/pull/12279) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Implemented conversions to the common type for `LowCardinality` types. This allows to execute UNION ALL of tables with columns of LowCardinality and other columns. This fixes [#8212](https://github.com/ClickHouse/ClickHouse/issues/8212). This fixes [#4342](https://github.com/ClickHouse/ClickHouse/issues/4342). [#12275](https://github.com/ClickHouse/ClickHouse/pull/12275) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the behaviour when during multiple sequential inserts in `StorageFile` header for some special types was written more than once. This fixed [#6155](https://github.com/ClickHouse/ClickHouse/issues/6155). [#12197](https://github.com/ClickHouse/ClickHouse/pull/12197) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed logical functions for UInt8 values when they are not equal to 0 or 1. [#12196](https://github.com/ClickHouse/ClickHouse/pull/12196) ([Alexander Kazakov](https://github.com/Akazz)).
+* Cap max_memory_usage* limits to the process resident memory. [#12182](https://github.com/ClickHouse/ClickHouse/pull/12182) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed `dictGet` arguments check during GROUP BY injective functions elimination. [#12179](https://github.com/ClickHouse/ClickHouse/pull/12179) ([Azat Khuzhin](https://github.com/azat)).
+* Don't split the dictionary source's table name into schema and table name itself if ODBC connection does not support schema. [#12165](https://github.com/ClickHouse/ClickHouse/pull/12165) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed wrong logic in `ALTER DELETE` that leads to deleting of records when condition evaluates to NULL. This fixes [#9088](https://github.com/ClickHouse/ClickHouse/issues/9088). This closes [#12106](https://github.com/ClickHouse/ClickHouse/issues/12106). [#12153](https://github.com/ClickHouse/ClickHouse/pull/12153) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed transform of query to send to external DBMS (e.g. MySQL, ODBC) in presense of aliases. This fixes [#12032](https://github.com/ClickHouse/ClickHouse/issues/12032). [#12151](https://github.com/ClickHouse/ClickHouse/pull/12151) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential overflow in integer division. This fixes [#12119](https://github.com/ClickHouse/ClickHouse/issues/12119). [#12140](https://github.com/ClickHouse/ClickHouse/pull/12140) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential infinite loop in `greatCircleDistance`, `geoDistance`. This fixes [#12117](https://github.com/ClickHouse/ClickHouse/issues/12117). [#12137](https://github.com/ClickHouse/ClickHouse/pull/12137) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Normalize "pid" file handling. In previous versions the server may refuse to start if it was killed without proper shutdown and if there is another process that has the same pid as previously runned server. Also pid file may be removed in unsuccessful server startup even if there is another server running. This fixes [#3501](https://github.com/ClickHouse/ClickHouse/issues/3501). [#12133](https://github.com/ClickHouse/ClickHouse/pull/12133) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed handling dependency of table with ENGINE=Dictionary on dictionary. This fixes [#10994](https://github.com/ClickHouse/ClickHouse/issues/10994). This fixes [#10397](https://github.com/ClickHouse/ClickHouse/issues/10397). [#12116](https://github.com/ClickHouse/ClickHouse/pull/12116) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed performance for selects with `UNION` caused by wrong limit for the total number of threads. Fixes [#12030](https://github.com/ClickHouse/ClickHouse/issues/12030). [#12103](https://github.com/ClickHouse/ClickHouse/pull/12103) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed segfault with `-StateResample` combinators. [#12092](https://github.com/ClickHouse/ClickHouse/pull/12092) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed empty `result_rows` and `result_bytes` metrics in `system.quey_log` for selects. Fixes [#11595](https://github.com/ClickHouse/ClickHouse/issues/11595). [#12089](https://github.com/ClickHouse/ClickHouse/pull/12089) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed unnecessary limiting the number of threads for selects from `VIEW`. Fixes [#11937](https://github.com/ClickHouse/ClickHouse/issues/11937). [#12085](https://github.com/ClickHouse/ClickHouse/pull/12085) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed possible crash while using wrong type for `PREWHERE`. Fixes [#12053](https://github.com/ClickHouse/ClickHouse/issues/12053), [#12060](https://github.com/ClickHouse/ClickHouse/issues/12060). [#12060](https://github.com/ClickHouse/ClickHouse/pull/12060) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed error `Expected single dictionary argument for function` for function `defaultValueOfArgumentType` with `LowCardinality` type. Fixes [#11808](https://github.com/ClickHouse/ClickHouse/issues/11808). [#12056](https://github.com/ClickHouse/ClickHouse/pull/12056) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed error `Cannot capture column` for higher-order functions with `Tuple(LowCardinality)` argument. Fixes [#9766](https://github.com/ClickHouse/ClickHouse/issues/9766). [#12055](https://github.com/ClickHouse/ClickHouse/pull/12055) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Parse tables metadata in parallel when loading database. This fixes slow server startup when there are large number of tables. [#12045](https://github.com/ClickHouse/ClickHouse/pull/12045) ([tavplubix](https://github.com/tavplubix)).
+* Make `topK` aggregate function return Enum for Enum types. This fixes [#3740](https://github.com/ClickHouse/ClickHouse/issues/3740). [#12043](https://github.com/ClickHouse/ClickHouse/pull/12043) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed constraints check if constraint is a constant expression. This fixes [#11360](https://github.com/ClickHouse/ClickHouse/issues/11360). [#12042](https://github.com/ClickHouse/ClickHouse/pull/12042) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed incorrect comparison of tuples with `Nullable` columns. Fixes [#11985](https://github.com/ClickHouse/ClickHouse/issues/11985). [#12039](https://github.com/ClickHouse/ClickHouse/pull/12039) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed calculation of access rights when allow_introspection_functions=0. [#12031](https://github.com/ClickHouse/ClickHouse/pull/12031) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed wrong result and potential crash when invoking function `if` with arguments of type `FixedString` with different sizes. This fixes [#11362](https://github.com/ClickHouse/ClickHouse/issues/11362). [#12021](https://github.com/ClickHouse/ClickHouse/pull/12021) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* A query with function `neighbor` as the only returned expression may return empty result if the function is called with offset `-9223372036854775808`. This fixes [#11367](https://github.com/ClickHouse/ClickHouse/issues/11367). [#12019](https://github.com/ClickHouse/ClickHouse/pull/12019) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed calculation of access rights when allow_ddl=0. [#12015](https://github.com/ClickHouse/ClickHouse/pull/12015) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed potential array size overflow in generateRandom that may lead to crash. This fixes [#11371](https://github.com/ClickHouse/ClickHouse/issues/11371). [#12013](https://github.com/ClickHouse/ClickHouse/pull/12013) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential floating point exception. This closes [#11378](https://github.com/ClickHouse/ClickHouse/issues/11378). [#12005](https://github.com/ClickHouse/ClickHouse/pull/12005) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed wrong setting name in log message at server startup. [#11997](https://github.com/ClickHouse/ClickHouse/pull/11997) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `Query parameter was not set` in `Values` format. Fixes [#11918](https://github.com/ClickHouse/ClickHouse/issues/11918). [#11936](https://github.com/ClickHouse/ClickHouse/pull/11936) ([tavplubix](https://github.com/tavplubix)).
+* Keep aliases for substitutions in query (parametrized queries). This fixes [#11914](https://github.com/ClickHouse/ClickHouse/issues/11914). [#11916](https://github.com/ClickHouse/ClickHouse/pull/11916) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed bug with no moves when changing storage policy from default one. [#11893](https://github.com/ClickHouse/ClickHouse/pull/11893) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fixed potential floating point exception when parsing `DateTime64`. This fixes [#11374](https://github.com/ClickHouse/ClickHouse/issues/11374). [#11875](https://github.com/ClickHouse/ClickHouse/pull/11875) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed memory accounting via HTTP interface (can be significant with `wait_end_of_query=1`). [#11840](https://github.com/ClickHouse/ClickHouse/pull/11840) ([Azat Khuzhin](https://github.com/azat)).
+* Parse metadata stored in zookeeper before checking for equality. [#11739](https://github.com/ClickHouse/ClickHouse/pull/11739) ([Azat Khuzhin](https://github.com/azat)).
+
+#### Performance Improvement
+
+* Index not used for IN operator with literals, performance regression introduced around v19.3. This fixes [#10574](https://github.com/ClickHouse/ClickHouse/issues/10574). [#12062](https://github.com/ClickHouse/ClickHouse/pull/12062) ([nvartolomei](https://github.com/nvartolomei)).
+
+#### Build/Testing/Packaging Improvement
+
+* Install `ca-certificates` before the first `apt-get update` in Dockerfile. [#12095](https://github.com/ClickHouse/ClickHouse/pull/12095) ([Ivan Blinkov](https://github.com/blinkov)).
+
+
+### ClickHouse release v20.4.6.53-stable 2020-06-25
+
+#### Bug Fix
+
+* Fix rare crash caused by using `Nullable` column in prewhere condition. Continuation of [#11608](https://github.com/ClickHouse/ClickHouse/issues/11608). [#11869](https://github.com/ClickHouse/ClickHouse/pull/11869) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Don't allow arrayJoin inside higher order functions. It was leading to broken protocol synchronization. This closes [#3933](https://github.com/ClickHouse/ClickHouse/issues/3933). [#11846](https://github.com/ClickHouse/ClickHouse/pull/11846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix wrong result of comparison of FixedString with constant String. This fixes [#11393](https://github.com/ClickHouse/ClickHouse/issues/11393). This bug appeared in version 20.4. [#11828](https://github.com/ClickHouse/ClickHouse/pull/11828) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix wrong result for `if()` with NULLs in condition. [#11807](https://github.com/ClickHouse/ClickHouse/pull/11807) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix using too many threads for queries. [#11788](https://github.com/ClickHouse/ClickHouse/pull/11788) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix unexpected behaviour of queries like `SELECT *, xyz.*` which were success while an error expected. [#11753](https://github.com/ClickHouse/ClickHouse/pull/11753) ([hexiaoting](https://github.com/hexiaoting)).
+* Now replicated fetches will be cancelled during metadata alter. [#11744](https://github.com/ClickHouse/ClickHouse/pull/11744) ([alesapin](https://github.com/alesapin)).
+* Fixed LOGICAL_ERROR caused by wrong type deduction of complex literals in Values input format. [#11732](https://github.com/ClickHouse/ClickHouse/pull/11732) ([tavplubix](https://github.com/tavplubix)).
+* Fix `ORDER BY ... WITH FILL` over const columns. [#11697](https://github.com/ClickHouse/ClickHouse/pull/11697) ([Anton Popov](https://github.com/CurtizJ)).
+* Pass proper timeouts when communicating with XDBC bridge. Recently timeouts were not respected when checking bridge liveness and receiving meta info. [#11690](https://github.com/ClickHouse/ClickHouse/pull/11690) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `LIMIT n WITH TIES` usage together with `ORDER BY` statement, which contains aliases. [#11689](https://github.com/ClickHouse/ClickHouse/pull/11689) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix error which leads to an incorrect state of `system.mutations`. It may show that whole mutation is already done but the server still has `MUTATE_PART` tasks in the replication queue and tries to execute them. This fixes [#11611](https://github.com/ClickHouse/ClickHouse/issues/11611). [#11681](https://github.com/ClickHouse/ClickHouse/pull/11681) ([alesapin](https://github.com/alesapin)).
+* Add support for regular expressions with case-insensitive flags. This fixes [#11101](https://github.com/ClickHouse/ClickHouse/issues/11101) and fixes [#11506](https://github.com/ClickHouse/ClickHouse/issues/11506). [#11649](https://github.com/ClickHouse/ClickHouse/pull/11649) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove trivial count query optimization if row-level security is set. In previous versions the user get total count of records in a table instead filtered. This fixes [#11352](https://github.com/ClickHouse/ClickHouse/issues/11352). [#11644](https://github.com/ClickHouse/ClickHouse/pull/11644) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bloom filters for String (data skipping indices). [#11638](https://github.com/ClickHouse/ClickHouse/pull/11638) ([Azat Khuzhin](https://github.com/azat)).
+* Fix rare crash caused by using `Nullable` column in prewhere condition. (Probably it is connected with [#11572](https://github.com/ClickHouse/ClickHouse/issues/11572) somehow). [#11608](https://github.com/ClickHouse/ClickHouse/pull/11608) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix error `Block structure mismatch` for queries with sampling reading from `Buffer` table. [#11602](https://github.com/ClickHouse/ClickHouse/pull/11602) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix wrong exit code of the clickhouse-client, when exception.code() % 256 = 0. [#11601](https://github.com/ClickHouse/ClickHouse/pull/11601) ([filimonov](https://github.com/filimonov)).
+* Fix trivial error in log message about "Mark cache size was lowered" at server startup. This closes [#11399](https://github.com/ClickHouse/ClickHouse/issues/11399). [#11589](https://github.com/ClickHouse/ClickHouse/pull/11589) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix error `Size of offsets does not match size of column` for queries with `PREWHERE column in (subquery)` and `ARRAY JOIN`. [#11580](https://github.com/ClickHouse/ClickHouse/pull/11580) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed rare segfault in `SHOW CREATE TABLE` Fixes [#11490](https://github.com/ClickHouse/ClickHouse/issues/11490). [#11579](https://github.com/ClickHouse/ClickHouse/pull/11579) ([tavplubix](https://github.com/tavplubix)).
+* All queries in HTTP session have had the same query_id. It is fixed. [#11578](https://github.com/ClickHouse/ClickHouse/pull/11578) ([tavplubix](https://github.com/tavplubix)).
+* Now clickhouse-server docker container will prefer IPv6 checking server aliveness. [#11550](https://github.com/ClickHouse/ClickHouse/pull/11550) ([Ivan Starkov](https://github.com/istarkov)).
+* Fix shard_num/replica_num for `<node>` (breaks use_compact_format_in_distributed_parts_names). [#11528](https://github.com/ClickHouse/ClickHouse/pull/11528) ([Azat Khuzhin](https://github.com/azat)).
+* Fix race condition which may lead to an exception during table drop. It's a bit tricky and not dangerous at all. If you want an explanation, just notice me in telegram. [#11523](https://github.com/ClickHouse/ClickHouse/pull/11523) ([alesapin](https://github.com/alesapin)).
+* Fix memory leak when exception is thrown in the middle of aggregation with -State functions. This fixes [#8995](https://github.com/ClickHouse/ClickHouse/issues/8995). [#11496](https://github.com/ClickHouse/ClickHouse/pull/11496) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* If data skipping index is dependent on columns that are going to be modified during background merge (for SummingMergeTree, AggregatingMergeTree as well as for TTL GROUP BY), it was calculated incorrectly. This issue is fixed by moving index calculation after merge so the index is calculated on merged data. [#11162](https://github.com/ClickHouse/ClickHouse/pull/11162) ([Azat Khuzhin](https://github.com/azat)).
+* Get rid of old libunwind patches. https://github.com/ClickHouse-Extras/libunwind/commit/500aa227911bd185a94bfc071d68f4d3b03cb3b1#r39048012 This allows to disable `-fno-omit-frame-pointer` in `clang` builds that improves performance at least by 1% in average. [#10761](https://github.com/ClickHouse/ClickHouse/pull/10761) ([Amos Bird](https://github.com/amosbird)).
+* Fix usage of primary key wrapped into a function with 'FINAL' modifier and 'ORDER BY' optimization. [#10715](https://github.com/ClickHouse/ClickHouse/pull/10715) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Build/Testing/Packaging Improvement
+
+* Fix several non significant errors in unit tests. [#11262](https://github.com/ClickHouse/ClickHouse/pull/11262) ([alesapin](https://github.com/alesapin)).
+* Fix (false) MSan report in MergeTreeIndexFullText. The issue first appeared in [#9968](https://github.com/ClickHouse/ClickHouse/issues/9968). [#10801](https://github.com/ClickHouse/ClickHouse/pull/10801) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+
+### ClickHouse release v20.4.5.36-stable 2020-06-10
+
+#### Bug Fix
+
+* Fix the error `Data compressed with different methods` that can happen if `min_bytes_to_use_direct_io` is enabled and PREWHERE is active and using SAMPLE or high number of threads. This fixes [#11539](https://github.com/ClickHouse/ClickHouse/issues/11539). [#11540](https://github.com/ClickHouse/ClickHouse/pull/11540) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix return compressed size for codecs. [#11448](https://github.com/ClickHouse/ClickHouse/pull/11448) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix server crash when a column has compression codec with non-literal arguments. Fixes [#11365](https://github.com/ClickHouse/ClickHouse/issues/11365). [#11431](https://github.com/ClickHouse/ClickHouse/pull/11431) ([alesapin](https://github.com/alesapin)).
+* Fix pointInPolygon with nan as point. Fixes [#11375](https://github.com/ClickHouse/ClickHouse/issues/11375). [#11421](https://github.com/ClickHouse/ClickHouse/pull/11421) ([Alexey Ilyukhov](https://github.com/livace)).
+* Fix potential uninitialized memory read in MergeTree shutdown if table was not created successfully. [#11420](https://github.com/ClickHouse/ClickHouse/pull/11420) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed geohashesInBox with arguments outside of latitude/longitude range. [#11403](https://github.com/ClickHouse/ClickHouse/pull/11403) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fix possible `Pipeline stuck` error for queries with external sort and limit. Fixes [#11359](https://github.com/ClickHouse/ClickHouse/issues/11359). [#11366](https://github.com/ClickHouse/ClickHouse/pull/11366) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Remove redundant lock during parts send in ReplicatedMergeTree. [#11354](https://github.com/ClickHouse/ClickHouse/pull/11354) ([alesapin](https://github.com/alesapin)).
+* Fix support for `\G` (vertical output) in clickhouse-client in multiline mode. This closes [#9933](https://github.com/ClickHouse/ClickHouse/issues/9933). [#11350](https://github.com/ClickHouse/ClickHouse/pull/11350) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix potential segfault when using `Lazy` database. [#11348](https://github.com/ClickHouse/ClickHouse/pull/11348) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash in `quantilesExactWeightedArray`. [#11337](https://github.com/ClickHouse/ClickHouse/pull/11337) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Now merges stopped before change metadata in `ALTER` queries. [#11335](https://github.com/ClickHouse/ClickHouse/pull/11335) ([alesapin](https://github.com/alesapin)).
+* Make writing to `MATERIALIZED VIEW` with setting `parallel_view_processing = 1` parallel again. Fixes [#10241](https://github.com/ClickHouse/ClickHouse/issues/10241). [#11330](https://github.com/ClickHouse/ClickHouse/pull/11330) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix visitParamExtractRaw when extracted JSON has strings with unbalanced { or [. [#11318](https://github.com/ClickHouse/ClickHouse/pull/11318) ([Ewout](https://github.com/devwout)).
+* Fix very rare race condition in ThreadPool. [#11314](https://github.com/ClickHouse/ClickHouse/pull/11314) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix insignificant data race in clickhouse-copier. Found by integration tests. [#11313](https://github.com/ClickHouse/ClickHouse/pull/11313) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix potential uninitialized memory in conversion. Example: `SELECT toIntervalSecond(now64())`. [#11311](https://github.com/ClickHouse/ClickHouse/pull/11311) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix the issue when index analysis cannot work if a table has Array column in primary key and if a query is filtering by this column with `empty` or `notEmpty` functions. This fixes [#11286](https://github.com/ClickHouse/ClickHouse/issues/11286). [#11303](https://github.com/ClickHouse/ClickHouse/pull/11303) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bug when query speed estimation can be incorrect and the limit of `min_execution_speed` may not work or work incorrectly if the query is throttled by `max_network_bandwidth`, `max_execution_speed` or `priority` settings. Change the default value of `timeout_before_checking_execution_speed` to non-zero, because otherwise the settings `min_execution_speed` and `max_execution_speed` have no effect. This fixes [#11297](https://github.com/ClickHouse/ClickHouse/issues/11297). This fixes [#5732](https://github.com/ClickHouse/ClickHouse/issues/5732). This fixes [#6228](https://github.com/ClickHouse/ClickHouse/issues/6228). Usability improvement: avoid concatenation of exception message with progress bar in `clickhouse-client`. [#11296](https://github.com/ClickHouse/ClickHouse/pull/11296) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash when SET DEFAULT ROLE is called with wrong arguments. This fixes [#10586](https://github.com/ClickHouse/ClickHouse/issues/10586). [#11278](https://github.com/ClickHouse/ClickHouse/pull/11278) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix crash while reading malformed data in Protobuf format. This fixes [#5957](https://github.com/ClickHouse/ClickHouse/issues/5957), fixes [#11203](https://github.com/ClickHouse/ClickHouse/issues/11203). [#11258](https://github.com/ClickHouse/ClickHouse/pull/11258) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed a bug when cache-dictionary could return default value instead of normal (when there are only expired keys). This affects only string fields. [#11233](https://github.com/ClickHouse/ClickHouse/pull/11233) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix error `Block structure mismatch in QueryPipeline` while reading from `VIEW` with constants in inner query. Fixes [#11181](https://github.com/ClickHouse/ClickHouse/issues/11181). [#11205](https://github.com/ClickHouse/ClickHouse/pull/11205) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix possible exception `Invalid status for associated output`. [#11200](https://github.com/ClickHouse/ClickHouse/pull/11200) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix possible error `Cannot capture column` for higher-order functions with `Array(Array(LowCardinality))` captured argument. [#11185](https://github.com/ClickHouse/ClickHouse/pull/11185) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed S3 globbing which could fail in case of more than 1000 keys and some backends. [#11179](https://github.com/ClickHouse/ClickHouse/pull/11179) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* If data skipping index is dependent on columns that are going to be modified during background merge (for SummingMergeTree, AggregatingMergeTree as well as for TTL GROUP BY), it was calculated incorrectly. This issue is fixed by moving index calculation after merge so the index is calculated on merged data. [#11162](https://github.com/ClickHouse/ClickHouse/pull/11162) ([Azat Khuzhin](https://github.com/azat)).
+* Fix Kafka performance issue related to reschedules based on limits, which were always applied. [#11149](https://github.com/ClickHouse/ClickHouse/pull/11149) ([filimonov](https://github.com/filimonov)).
+* Fix for the hang which was happening sometimes during DROP of table engine=Kafka (or during server restarts). [#11145](https://github.com/ClickHouse/ClickHouse/pull/11145) ([filimonov](https://github.com/filimonov)).
+* Fix excessive reserving of threads for simple queries (optimization for reducing the number of threads, which was partly broken after changes in pipeline). [#11114](https://github.com/ClickHouse/ClickHouse/pull/11114) ([Azat Khuzhin](https://github.com/azat)).
+* Fix predicates optimization for distributed queries (`enable_optimize_predicate_expression=1`) for queries with `HAVING` section (i.e. when filtering on the server initiator is required), by preserving the order of expressions (and this is enough to fix), and also force aggregator use column names over indexes. Fixes: [#10613](https://github.com/ClickHouse/ClickHouse/issues/10613), [#11413](https://github.com/ClickHouse/ClickHouse/issues/11413). [#10621](https://github.com/ClickHouse/ClickHouse/pull/10621) ([Azat Khuzhin](https://github.com/azat)).
+
+#### Build/Testing/Packaging Improvement
+
+* Fix several flaky integration tests. [#11355](https://github.com/ClickHouse/ClickHouse/pull/11355) ([alesapin](https://github.com/alesapin)).
+
+### ClickHouse release v20.4.4.18-stable 2020-05-26
+
+No changes compared to v20.4.3.16-stable.
+
+### ClickHouse release v20.4.3.16-stable 2020-05-23
+
+#### Bug Fix
+
+* Removed logging from mutation finalization task if nothing was finalized. [#11109](https://github.com/ClickHouse/ClickHouse/pull/11109) ([alesapin](https://github.com/alesapin)).
+* Fixed memory leak in registerDiskS3. [#11074](https://github.com/ClickHouse/ClickHouse/pull/11074) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fixed the potential missed data during termination of Kafka engine table. [#11048](https://github.com/ClickHouse/ClickHouse/pull/11048) ([filimonov](https://github.com/filimonov)).
+* Fixed `parseDateTime64BestEffort` argument resolution bugs. [#11038](https://github.com/ClickHouse/ClickHouse/pull/11038) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fixed very rare potential use-after-free error in `MergeTree` if table was not created successfully. [#10986](https://github.com/ClickHouse/ClickHouse/pull/10986), [#10970](https://github.com/ClickHouse/ClickHouse/pull/10970) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed metadata (relative path for rename) and data (relative path for symlink) handling for Atomic database. [#10980](https://github.com/ClickHouse/ClickHouse/pull/10980) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed server crash on concurrent `ALTER` and `DROP DATABASE` queries with `Atomic` database engine. [#10968](https://github.com/ClickHouse/ClickHouse/pull/10968) ([tavplubix](https://github.com/tavplubix)).
+* Fixed incorrect raw data size in `getRawData()` method. [#10964](https://github.com/ClickHouse/ClickHouse/pull/10964) ([Igr](https://github.com/ObjatieGroba)).
+* Fixed incompatibility of two-level aggregation between versions 20.1 and earlier. This incompatibility happens when different versions of ClickHouse are used on initiator node and remote nodes and the size of GROUP BY result is large and aggregation is performed by a single String field. It leads to several unmerged rows for a single key in result. [#10952](https://github.com/ClickHouse/ClickHouse/pull/10952) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed sending partially written files by the `DistributedBlockOutputStream`. [#10940](https://github.com/ClickHouse/ClickHouse/pull/10940) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed crash in `SELECT count(notNullIn(NULL, []))`. [#10920](https://github.com/ClickHouse/ClickHouse/pull/10920) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed the hang which was happening sometimes during `DROP` of `Kafka` table engine. (or during server restarts). [#10910](https://github.com/ClickHouse/ClickHouse/pull/10910) ([filimonov](https://github.com/filimonov)).
+* Fixed the impossibility of executing multiple `ALTER RENAME` like `a TO b, c TO a`. [#10895](https://github.com/ClickHouse/ClickHouse/pull/10895) ([alesapin](https://github.com/alesapin)).
+* Fixed possible race which could happen when you get result from aggregate function state from multiple thread for the same column. The only way it can happen is when you use `finalizeAggregation` function while reading from table with `Memory` engine which stores `AggregateFunction` state for `quantile*` function. [#10890](https://github.com/ClickHouse/ClickHouse/pull/10890) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed backward compatibility with tuples in Distributed tables. [#10889](https://github.com/ClickHouse/ClickHouse/pull/10889) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed `SIGSEGV` in `StringHashTable` if such a key does not exist. [#10870](https://github.com/ClickHouse/ClickHouse/pull/10870) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed `WATCH` hangs after `LiveView` table was dropped from database with `Atomic` engine. [#10859](https://github.com/ClickHouse/ClickHouse/pull/10859) ([tavplubix](https://github.com/tavplubix)).
+* Fixed bug in `ReplicatedMergeTree` which might cause some `ALTER` on `OPTIMIZE` query to hang waiting for some replica after it become inactive. [#10849](https://github.com/ClickHouse/ClickHouse/pull/10849) ([tavplubix](https://github.com/tavplubix)).
+* Now constraints are updated if the column participating in `CONSTRAINT` expression was renamed. Fixes [#10844](https://github.com/ClickHouse/ClickHouse/issues/10844). [#10847](https://github.com/ClickHouse/ClickHouse/pull/10847) ([alesapin](https://github.com/alesapin)).
+* Fixed potential read of uninitialized memory in cache-dictionary. [#10834](https://github.com/ClickHouse/ClickHouse/pull/10834) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed columns order after `Block::sortColumns()`. [#10826](https://github.com/ClickHouse/ClickHouse/pull/10826) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed the issue with `ODBC` bridge when no quoting of identifiers is requested. Fixes [#7984](https://github.com/ClickHouse/ClickHouse/issues/7984). [#10821](https://github.com/ClickHouse/ClickHouse/pull/10821) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `UBSan` and `MSan` report in `DateLUT`. [#10798](https://github.com/ClickHouse/ClickHouse/pull/10798) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed incorrect type conversion in key conditions. Fixes [#6287](https://github.com/ClickHouse/ClickHouse/issues/6287). [#10791](https://github.com/ClickHouse/ClickHouse/pull/10791) ([Andrew Onyshchuk](https://github.com/oandrew)).
+* Fixed `parallel_view_processing` behavior. Now all insertions into `MATERIALIZED VIEW` without exception should be finished if exception happened. Fixes [#10241](https://github.com/ClickHouse/ClickHouse/issues/10241). [#10757](https://github.com/ClickHouse/ClickHouse/pull/10757) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed combinator `-OrNull` and `-OrDefault` when combined with `-State`. [#10741](https://github.com/ClickHouse/ClickHouse/pull/10741) ([hcz](https://github.com/hczhcz)).
+* Fixed possible buffer overflow in function `h3EdgeAngle`. [#10711](https://github.com/ClickHouse/ClickHouse/pull/10711) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed bug which locks concurrent alters when table has a lot of parts. [#10659](https://github.com/ClickHouse/ClickHouse/pull/10659) ([alesapin](https://github.com/alesapin)).
+* Fixed `nullptr` dereference in `StorageBuffer` if server was shutdown before table startup. [#10641](https://github.com/ClickHouse/ClickHouse/pull/10641) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `optimize_skip_unused_shards` with `LowCardinality`. [#10611](https://github.com/ClickHouse/ClickHouse/pull/10611) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed handling condition variable for synchronous mutations. In some cases signals to that condition variable could be lost. [#10588](https://github.com/ClickHouse/ClickHouse/pull/10588) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fixed possible crash when `createDictionary()` is called before `loadStoredObject()` has finished. [#10587](https://github.com/ClickHouse/ClickHouse/pull/10587) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed `SELECT` of column `ALIAS` which default expression type different from column type. [#10563](https://github.com/ClickHouse/ClickHouse/pull/10563) ([Azat Khuzhin](https://github.com/azat)).
+* Implemented comparison between DateTime64 and String values. [#10560](https://github.com/ClickHouse/ClickHouse/pull/10560) ([Vasily Nemkov](https://github.com/Enmk)).
+* Disable `GROUP BY` sharding_key optimization by default (`optimize_distributed_group_by_sharding_key` had been introduced and turned of by default, due to trickery of sharding_key analyzing, simple example is `if` in sharding key) and fix it for `WITH ROLLUP/CUBE/TOTALS`. [#10516](https://github.com/ClickHouse/ClickHouse/pull/10516) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed [#10263](https://github.com/ClickHouse/ClickHouse/issues/10263). [#10486](https://github.com/ClickHouse/ClickHouse/pull/10486) ([Azat Khuzhin](https://github.com/azat)).
+* Added tests about `max_rows_to_sort` setting. [#10268](https://github.com/ClickHouse/ClickHouse/pull/10268) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added backward compatibility for create bloom filter index. [#10551](https://github.com/ClickHouse/ClickHouse/issues/10551). [#10569](https://github.com/ClickHouse/ClickHouse/pull/10569) ([Winter Zhang](https://github.com/zhang2014)).
+
+### ClickHouse release v20.4.2.9, 2020-05-12
+
+#### Backward Incompatible Change
+* System tables (e.g. system.query_log, system.trace_log, system.metric_log) are using compact data part format for parts smaller than 10 MiB in size. Compact data part format is supported since version 20.3. If you are going to downgrade to version less than 20.3, you should manually delete table data for system logs in `/var/lib/clickhouse/data/system/`.
+* When string comparison involves FixedString and compared arguments are of different sizes, do comparison as if smaller string is padded to the length of the larger. This is intented for SQL compatibility if we imagine that FixedString data type corresponds to SQL CHAR. This closes [#9272](https://github.com/ClickHouse/ClickHouse/issues/9272). [#10363](https://github.com/ClickHouse/ClickHouse/pull/10363) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Make SHOW CREATE TABLE multiline. Now it is more readable and more like MySQL. [#10049](https://github.com/ClickHouse/ClickHouse/pull/10049) ([Azat Khuzhin](https://github.com/azat))
+* Added a setting `validate_polygons` that is used in `pointInPolygon` function and enabled by default. [#9857](https://github.com/ClickHouse/ClickHouse/pull/9857) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### New Feature
+* Add support for secured connection from ClickHouse to Zookeeper [#10184](https://github.com/ClickHouse/ClickHouse/pull/10184) ([Konstantin Lebedev](https://github.com/xzkostyan))
+* Support custom HTTP handlers. See [#5436](https://github.com/ClickHouse/ClickHouse/issues/5436) for description. [#7572](https://github.com/ClickHouse/ClickHouse/pull/7572) ([Winter Zhang](https://github.com/zhang2014))
+* Add MessagePack Input/Output format. [#9889](https://github.com/ClickHouse/ClickHouse/pull/9889) ([Kruglov Pavel](https://github.com/Avogar))
+* Add Regexp input format. [#9196](https://github.com/ClickHouse/ClickHouse/pull/9196) ([Kruglov Pavel](https://github.com/Avogar))
+* Added output format `Markdown` for embedding tables in markdown documents. [#10317](https://github.com/ClickHouse/ClickHouse/pull/10317) ([Kruglov Pavel](https://github.com/Avogar))
+* Added support for custom settings section in dictionaries. Also fixes issue [#2829](https://github.com/ClickHouse/ClickHouse/issues/2829). [#10137](https://github.com/ClickHouse/ClickHouse/pull/10137) ([Artem Streltsov](https://github.com/kekekekule))
+* Added custom settings support in DDL-queries for `CREATE DICTIONARY` [#10465](https://github.com/ClickHouse/ClickHouse/pull/10465) ([Artem Streltsov](https://github.com/kekekekule))
+* Add simple server-wide memory profiler that will collect allocation contexts when server memory usage becomes higher than the next allocation threshold. [#10444](https://github.com/ClickHouse/ClickHouse/pull/10444) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add setting `always_fetch_merged_part` which restrict replica to merge parts by itself and always prefer dowloading from other replicas. [#10379](https://github.com/ClickHouse/ClickHouse/pull/10379) ([alesapin](https://github.com/alesapin))
+* Add function `JSONExtractKeysAndValuesRaw` which extracts raw data from JSON objects [#10378](https://github.com/ClickHouse/ClickHouse/pull/10378) ([hcz](https://github.com/hczhcz))
+* Add memory usage from OS to `system.asynchronous_metrics`. [#10361](https://github.com/ClickHouse/ClickHouse/pull/10361) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added generic variants for functions `least` and `greatest`. Now they work with arbitrary number of arguments of arbitrary types. This fixes [#4767](https://github.com/ClickHouse/ClickHouse/issues/4767) [#10318](https://github.com/ClickHouse/ClickHouse/pull/10318) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Now ClickHouse controls timeouts of dictionary sources on its side. Two new settings added to cache dictionary configuration: `strict_max_lifetime_seconds`, which is `max_lifetime` by default, and `query_wait_timeout_milliseconds`, which is one minute by default. The first settings is also useful with `allow_read_expired_keys` settings (to forbid reading very expired keys). [#10337](https://github.com/ClickHouse/ClickHouse/pull/10337) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Add log_queries_min_type to filter which entries will be written to query_log [#10053](https://github.com/ClickHouse/ClickHouse/pull/10053) ([Azat Khuzhin](https://github.com/azat))
+* Added function `isConstant`. This function checks whether its argument is constant expression and returns 1 or 0. It is intended for development, debugging and demonstration purposes. [#10198](https://github.com/ClickHouse/ClickHouse/pull/10198) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* add joinGetOrNull to return NULL when key is missing instead of returning the default value. [#10094](https://github.com/ClickHouse/ClickHouse/pull/10094) ([Amos Bird](https://github.com/amosbird))
+* Consider `NULL` to be equal to `NULL` in `IN` operator, if the option `transform_null_in` is set. [#10085](https://github.com/ClickHouse/ClickHouse/pull/10085) ([achimbab](https://github.com/achimbab))
+* Add `ALTER TABLE ... RENAME COLUMN` for MergeTree table engines family. [#9948](https://github.com/ClickHouse/ClickHouse/pull/9948) ([alesapin](https://github.com/alesapin))
+* Support parallel distributed INSERT SELECT. [#9759](https://github.com/ClickHouse/ClickHouse/pull/9759) ([vxider](https://github.com/Vxider))
+* Add ability to query Distributed over Distributed (w/o `distributed_group_by_no_merge`) ... [#9923](https://github.com/ClickHouse/ClickHouse/pull/9923) ([Azat Khuzhin](https://github.com/azat))
+* Add function `arrayReduceInRanges` which aggregates array elements in given ranges. [#9598](https://github.com/ClickHouse/ClickHouse/pull/9598) ([hcz](https://github.com/hczhcz))
+* Add Dictionary Status on prometheus exporter. [#9622](https://github.com/ClickHouse/ClickHouse/pull/9622) ([Guillaume Tassery](https://github.com/YiuRULE))
+* Add function `arrayAUC` [#8698](https://github.com/ClickHouse/ClickHouse/pull/8698) ([taiyang-li](https://github.com/taiyang-li))
+* Support `DROP VIEW` statement for better TPC-H compatibility. [#9831](https://github.com/ClickHouse/ClickHouse/pull/9831) ([Amos Bird](https://github.com/amosbird))
+* Add 'strict_order' option to windowFunnel() [#9773](https://github.com/ClickHouse/ClickHouse/pull/9773) ([achimbab](https://github.com/achimbab))
+* Support `DATE` and `TIMESTAMP` SQL operators, e.g. `SELECT date '2001-01-01'` [#9691](https://github.com/ClickHouse/ClickHouse/pull/9691) ([Artem Zuikov](https://github.com/4ertus2))
+
+#### Experimental Feature
+* Added experimental database engine Atomic. It supports non-blocking `DROP` and `RENAME TABLE` queries and atomic `EXCHANGE TABLES t1 AND t2` query [#7512](https://github.com/ClickHouse/ClickHouse/pull/7512) ([tavplubix](https://github.com/tavplubix))
+* Initial support for ReplicatedMergeTree over S3 (it works in suboptimal way) [#10126](https://github.com/ClickHouse/ClickHouse/pull/10126) ([Pavel Kovalenko](https://github.com/Jokser))
+
+#### Bug Fix
+* Fixed incorrect scalar results inside inner query of `MATERIALIZED VIEW` in case if this query contained dependent table [#10603](https://github.com/ClickHouse/ClickHouse/pull/10603) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fixed bug, which caused HTTP requests to get stuck on client closing connection when `readonly=2` and `cancel_http_readonly_queries_on_client_close=1`. [#10684](https://github.com/ClickHouse/ClickHouse/pull/10684) ([tavplubix](https://github.com/tavplubix))
+* Fix segfault in StorageBuffer when exception is thrown on server startup. Fixes [#10550](https://github.com/ClickHouse/ClickHouse/issues/10550) [#10609](https://github.com/ClickHouse/ClickHouse/pull/10609) ([tavplubix](https://github.com/tavplubix))
+* The query`SYSTEM DROP DNS CACHE` now also drops caches used to check if user is allowed to connect from some IP addresses [#10608](https://github.com/ClickHouse/ClickHouse/pull/10608) ([tavplubix](https://github.com/tavplubix))
+* Fix usage of multiple `IN` operators with an identical set in one query. Fixes [#10539](https://github.com/ClickHouse/ClickHouse/issues/10539) [#10686](https://github.com/ClickHouse/ClickHouse/pull/10686) ([Anton Popov](https://github.com/CurtizJ))
+* Fix crash in `generateRandom` with nested types. Fixes [#10583](https://github.com/ClickHouse/ClickHouse/issues/10583). [#10734](https://github.com/ClickHouse/ClickHouse/pull/10734) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix data corruption for `LowCardinality(FixedString)` key column in `SummingMergeTree` which could have happened after merge. Fixes [#10489](https://github.com/ClickHouse/ClickHouse/issues/10489). [#10721](https://github.com/ClickHouse/ClickHouse/pull/10721) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix logic for aggregation_memory_efficient_merge_threads setting. [#10667](https://github.com/ClickHouse/ClickHouse/pull/10667) ([palasonic1](https://github.com/palasonic1))
+* Fix disappearing totals. Totals could have being filtered if query had `JOIN` or subquery with external `WHERE` condition. Fixes [#10674](https://github.com/ClickHouse/ClickHouse/issues/10674) [#10698](https://github.com/ClickHouse/ClickHouse/pull/10698) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix the lack of parallel execution of remote queries with `distributed_aggregation_memory_efficient` enabled. Fixes [#10655](https://github.com/ClickHouse/ClickHouse/issues/10655) [#10664](https://github.com/ClickHouse/ClickHouse/pull/10664) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix possible incorrect number of rows for queries with `LIMIT`. Fixes [#10566](https://github.com/ClickHouse/ClickHouse/issues/10566), [#10709](https://github.com/ClickHouse/ClickHouse/issues/10709) [#10660](https://github.com/ClickHouse/ClickHouse/pull/10660) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix index corruption, which may occur in some cases after merging compact parts into another compact part. [#10531](https://github.com/ClickHouse/ClickHouse/pull/10531) ([Anton Popov](https://github.com/CurtizJ))
+* Fix the situation, when mutation finished all parts, but hung up in `is_done=0`. [#10526](https://github.com/ClickHouse/ClickHouse/pull/10526) ([alesapin](https://github.com/alesapin))
+* Fix overflow at beginning of unix epoch for timezones with fractional offset from UTC. Fixes [#9335](https://github.com/ClickHouse/ClickHouse/issues/9335). [#10513](https://github.com/ClickHouse/ClickHouse/pull/10513) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Better diagnostics for input formats. Fixes [#10204](https://github.com/ClickHouse/ClickHouse/issues/10204) [#10418](https://github.com/ClickHouse/ClickHouse/pull/10418) ([tavplubix](https://github.com/tavplubix))
+* Fix numeric overflow in `simpleLinearRegression()` over large integers [#10474](https://github.com/ClickHouse/ClickHouse/pull/10474) ([hcz](https://github.com/hczhcz))
+* Fix use-after-free in Distributed shutdown, avoid waiting for sending all batches [#10491](https://github.com/ClickHouse/ClickHouse/pull/10491) ([Azat Khuzhin](https://github.com/azat))
+* Add CA certificates to clickhouse-server docker image [#10476](https://github.com/ClickHouse/ClickHouse/pull/10476) ([filimonov](https://github.com/filimonov))
+* Fix a rare endless loop that might have occurred when using the `addressToLine` function or AggregateFunctionState columns. [#10466](https://github.com/ClickHouse/ClickHouse/pull/10466) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Handle zookeeper "no node error" during distributed query [#10050](https://github.com/ClickHouse/ClickHouse/pull/10050) ([Daniel Chen](https://github.com/Phantomape))
+* Fix bug when server cannot attach table after column's default was altered. [#10441](https://github.com/ClickHouse/ClickHouse/pull/10441) ([alesapin](https://github.com/alesapin))
+* Implicitly cast the default expression type to the column type for the ALIAS columns [#10563](https://github.com/ClickHouse/ClickHouse/pull/10563) ([Azat Khuzhin](https://github.com/azat))
+* Don't remove metadata directory if `ATTACH DATABASE` fails [#10442](https://github.com/ClickHouse/ClickHouse/pull/10442) ([Winter Zhang](https://github.com/zhang2014))
+* Avoid dependency on system tzdata. Fixes loading of `Africa/Casablanca` timezone on CentOS 8. Fixes [#10211](https://github.com/ClickHouse/ClickHouse/issues/10211) [#10425](https://github.com/ClickHouse/ClickHouse/pull/10425) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix some issues if data is inserted with quorum and then gets deleted (DROP PARTITION, TTL, etc.). It led to stuck of INSERTs or false-positive exceptions in SELECTs. Fixes [#9946](https://github.com/ClickHouse/ClickHouse/issues/9946) [#10188](https://github.com/ClickHouse/ClickHouse/pull/10188) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Check the number and type of arguments when creating BloomFilter index [#9623](https://github.com/ClickHouse/ClickHouse/issues/9623) [#10431](https://github.com/ClickHouse/ClickHouse/pull/10431) ([Winter Zhang](https://github.com/zhang2014))
+* Prefer `fallback_to_stale_replicas` over `skip_unavailable_shards`, otherwise when both settings specified and there are no up-to-date replicas the query will fail (patch from @alex-zaitsev ) [#10422](https://github.com/ClickHouse/ClickHouse/pull/10422) ([Azat Khuzhin](https://github.com/azat))
+* Fix the issue when a query with ARRAY JOIN, ORDER BY and LIMIT may return incomplete result. Fixes [#10226](https://github.com/ClickHouse/ClickHouse/issues/10226). [#10427](https://github.com/ClickHouse/ClickHouse/pull/10427) ([Vadim Plakhtinskiy](https://github.com/VadimPlh))
+* Add database name to dictionary name after DETACH/ATTACH. Fixes system.dictionaries table and `SYSTEM RELOAD` query [#10415](https://github.com/ClickHouse/ClickHouse/pull/10415) ([Azat Khuzhin](https://github.com/azat))
+* Fix possible incorrect result for extremes in processors pipeline. [#10131](https://github.com/ClickHouse/ClickHouse/pull/10131) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix possible segfault when the setting `distributed_group_by_no_merge` is enabled (introduced in 20.3.7.46 by [#10131](https://github.com/ClickHouse/ClickHouse/issues/10131)). [#10399](https://github.com/ClickHouse/ClickHouse/pull/10399) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix wrong flattening of `Array(Tuple(...))` data types. Fixes [#10259](https://github.com/ClickHouse/ClickHouse/issues/10259) [#10390](https://github.com/ClickHouse/ClickHouse/pull/10390) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix column names of constants inside JOIN that may clash with names of constants outside of JOIN [#9950](https://github.com/ClickHouse/ClickHouse/pull/9950) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Fix order of columns after Block::sortColumns() [#10826](https://github.com/ClickHouse/ClickHouse/pull/10826) ([Azat Khuzhin](https://github.com/azat))
+* Fix possible `Pipeline stuck` error in `ConcatProcessor` which may happen in remote query. [#10381](https://github.com/ClickHouse/ClickHouse/pull/10381) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Don't make disk reservations for aggregations. Fixes [#9241](https://github.com/ClickHouse/ClickHouse/issues/9241) [#10375](https://github.com/ClickHouse/ClickHouse/pull/10375) ([Azat Khuzhin](https://github.com/azat))
+* Fix wrong behaviour of datetime functions for timezones that has altered between positive and negative offsets from UTC (e.g. Pacific/Kiritimati). Fixes [#7202](https://github.com/ClickHouse/ClickHouse/issues/7202) [#10369](https://github.com/ClickHouse/ClickHouse/pull/10369) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Avoid infinite loop in `dictIsIn` function. Fixes #515 [#10365](https://github.com/ClickHouse/ClickHouse/pull/10365) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Disable GROUP BY sharding_key optimization by default and fix it for WITH ROLLUP/CUBE/TOTALS [#10516](https://github.com/ClickHouse/ClickHouse/pull/10516) ([Azat Khuzhin](https://github.com/azat))
+* Check for error code when checking parts and don't mark part as broken if the error is like "not enough memory". Fixes [#6269](https://github.com/ClickHouse/ClickHouse/issues/6269) [#10364](https://github.com/ClickHouse/ClickHouse/pull/10364) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Show information about not loaded dictionaries in system tables. [#10234](https://github.com/ClickHouse/ClickHouse/pull/10234) ([Vitaly Baranov](https://github.com/vitlibar))
+* Fix nullptr dereference in StorageBuffer if server was shutdown before table startup. [#10641](https://github.com/ClickHouse/ClickHouse/pull/10641) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed `DROP` vs `OPTIMIZE` race in `ReplicatedMergeTree`. `DROP` could left some garbage in replica path in ZooKeeper if there was concurrent `OPTIMIZE` query. [#10312](https://github.com/ClickHouse/ClickHouse/pull/10312) ([tavplubix](https://github.com/tavplubix))
+* Fix 'Logical error: CROSS JOIN has expressions' error for queries with comma and names joins mix. Fixes [#9910](https://github.com/ClickHouse/ClickHouse/issues/9910) [#10311](https://github.com/ClickHouse/ClickHouse/pull/10311) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix queries with `max_bytes_before_external_group_by`. [#10302](https://github.com/ClickHouse/ClickHouse/pull/10302) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix the issue with limiting maximum recursion depth in parser in certain cases. This fixes [#10283](https://github.com/ClickHouse/ClickHouse/issues/10283) This fix may introduce minor incompatibility: long and deep queries via clickhouse-client may refuse to work, and you should adjust settings `max_query_size` and `max_parser_depth` accordingly. [#10295](https://github.com/ClickHouse/ClickHouse/pull/10295) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Allow to use `count(*)` with multiple JOINs. Fixes [#9853](https://github.com/ClickHouse/ClickHouse/issues/9853) [#10291](https://github.com/ClickHouse/ClickHouse/pull/10291) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix error `Pipeline stuck` with `max_rows_to_group_by` and `group_by_overflow_mode = 'break'`. [#10279](https://github.com/ClickHouse/ClickHouse/pull/10279) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix 'Cannot add column' error while creating `range_hashed` dictionary using DDL query. Fixes [#10093](https://github.com/ClickHouse/ClickHouse/issues/10093). [#10235](https://github.com/ClickHouse/ClickHouse/pull/10235) ([alesapin](https://github.com/alesapin))
+* Fix rare possible exception `Cannot drain connections: cancel first`. [#10239](https://github.com/ClickHouse/ClickHouse/pull/10239) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fixed bug where ClickHouse would throw "Unknown function lambda." error message when user tries to run ALTER UPDATE/DELETE on tables with ENGINE = Replicated*. Check for nondeterministic functions now handles lambda expressions correctly. [#10237](https://github.com/ClickHouse/ClickHouse/pull/10237) ([Alexander Kazakov](https://github.com/Akazz))
+* Fixed reasonably rare segfault in StorageSystemTables that happens when SELECT ... FROM system.tables is run on a database with Lazy engine. [#10209](https://github.com/ClickHouse/ClickHouse/pull/10209) ([Alexander Kazakov](https://github.com/Akazz))
+* Fix possible infinite query execution when the query actually should stop on LIMIT, while reading from infinite source like `system.numbers` or `system.zeros`. [#10206](https://github.com/ClickHouse/ClickHouse/pull/10206) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fixed "generateRandom" function for Date type. This fixes [#9973](https://github.com/ClickHouse/ClickHouse/issues/9973). Fix an edge case when dates with year 2106 are inserted to MergeTree tables with old-style partitioning but partitions are named with year 1970. [#10218](https://github.com/ClickHouse/ClickHouse/pull/10218) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Convert types if the table definition of a View does not correspond to the SELECT query. This fixes [#10180](https://github.com/ClickHouse/ClickHouse/issues/10180) and [#10022](https://github.com/ClickHouse/ClickHouse/issues/10022) [#10217](https://github.com/ClickHouse/ClickHouse/pull/10217) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix `parseDateTimeBestEffort` for strings in RFC-2822 when day of week is Tuesday or Thursday. This fixes [#10082](https://github.com/ClickHouse/ClickHouse/issues/10082) [#10214](https://github.com/ClickHouse/ClickHouse/pull/10214) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix column names of constants inside JOIN that may clash with names of constants outside of JOIN. [#10207](https://github.com/ClickHouse/ClickHouse/pull/10207) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix move-to-prewhere optimization in presense of arrayJoin functions (in certain cases). This fixes [#10092](https://github.com/ClickHouse/ClickHouse/issues/10092) [#10195](https://github.com/ClickHouse/ClickHouse/pull/10195) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix issue with separator appearing in SCRAMBLE for native mysql-connector-java (JDBC) [#10140](https://github.com/ClickHouse/ClickHouse/pull/10140) ([BohuTANG](https://github.com/BohuTANG))
+* Fix using the current database for an access checking when the database isn't specified. [#10192](https://github.com/ClickHouse/ClickHouse/pull/10192) ([Vitaly Baranov](https://github.com/vitlibar))
+* Fix ALTER of tables with compact parts. [#10130](https://github.com/ClickHouse/ClickHouse/pull/10130) ([Anton Popov](https://github.com/CurtizJ))
+* Add the ability to relax the restriction on non-deterministic functions usage in mutations with `allow_nondeterministic_mutations` setting. [#10186](https://github.com/ClickHouse/ClickHouse/pull/10186) ([filimonov](https://github.com/filimonov))
+* Fix `DROP TABLE` invoked for dictionary [#10165](https://github.com/ClickHouse/ClickHouse/pull/10165) ([Azat Khuzhin](https://github.com/azat))
+* Convert blocks if structure does not match when doing `INSERT` into Distributed table [#10135](https://github.com/ClickHouse/ClickHouse/pull/10135) ([Azat Khuzhin](https://github.com/azat))
+* The number of rows was logged incorrectly (as sum across all parts) when inserted block is split by parts with partition key. [#10138](https://github.com/ClickHouse/ClickHouse/pull/10138) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add some arguments check and support identifier arguments for MySQL Database Engine [#10077](https://github.com/ClickHouse/ClickHouse/pull/10077) ([Winter Zhang](https://github.com/zhang2014))
+* Fix incorrect `index_granularity_bytes` check while creating new replica. Fixes [#10098](https://github.com/ClickHouse/ClickHouse/issues/10098). [#10121](https://github.com/ClickHouse/ClickHouse/pull/10121) ([alesapin](https://github.com/alesapin))
+* Fix bug in `CHECK TABLE` query when table contain skip indices. [#10068](https://github.com/ClickHouse/ClickHouse/pull/10068) ([alesapin](https://github.com/alesapin))
+* Fix Distributed-over-Distributed with the only one shard in a nested table [#9997](https://github.com/ClickHouse/ClickHouse/pull/9997) ([Azat Khuzhin](https://github.com/azat))
+* Fix possible rows loss for queries with `JOIN` and `UNION ALL`. Fixes [#9826](https://github.com/ClickHouse/ClickHouse/issues/9826), [#10113](https://github.com/ClickHouse/ClickHouse/issues/10113). ... [#10099](https://github.com/ClickHouse/ClickHouse/pull/10099) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix bug in dictionary when local clickhouse server is used as source. It may caused memory corruption if types in dictionary and source are not compatible. [#10071](https://github.com/ClickHouse/ClickHouse/pull/10071) ([alesapin](https://github.com/alesapin))
+* Fixed replicated tables startup when updating from an old ClickHouse version where `/table/replicas/replica_name/metadata` node does not exist. Fixes [#10037](https://github.com/ClickHouse/ClickHouse/issues/10037). [#10095](https://github.com/ClickHouse/ClickHouse/pull/10095) ([alesapin](https://github.com/alesapin))
+* Fix error `Cannot clone block with columns because block has 0 columns ... While executing GroupingAggregatedTransform`. It happened when setting `distributed_aggregation_memory_efficient` was enabled, and distributed query read aggregating data with mixed single and two-level aggregation from different shards.  [#10063](https://github.com/ClickHouse/ClickHouse/pull/10063) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix deadlock when database with materialized view failed attach at start [#10054](https://github.com/ClickHouse/ClickHouse/pull/10054) ([Azat Khuzhin](https://github.com/azat))
+* Fix a segmentation fault that could occur in GROUP BY over string keys containing trailing zero bytes ([#8636](https://github.com/ClickHouse/ClickHouse/issues/8636), [#8925](https://github.com/ClickHouse/ClickHouse/issues/8925)). ... [#10025](https://github.com/ClickHouse/ClickHouse/pull/10025) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Fix wrong results of distributed queries when alias could override qualified column name. Fixes [#9672](https://github.com/ClickHouse/ClickHouse/issues/9672) [#9714](https://github.com/ClickHouse/ClickHouse/issues/9714) [#9972](https://github.com/ClickHouse/ClickHouse/pull/9972) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix possible deadlock in `SYSTEM RESTART REPLICAS` [#9955](https://github.com/ClickHouse/ClickHouse/pull/9955) ([tavplubix](https://github.com/tavplubix))
+* Fix the number of threads used for remote query execution (performance regression, since 20.3). This happened when query from `Distributed` table was executed simultaneously on local and remote shards. Fixes [#9965](https://github.com/ClickHouse/ClickHouse/issues/9965) [#9971](https://github.com/ClickHouse/ClickHouse/pull/9971) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fixed `DeleteOnDestroy` logic in `ATTACH PART` which could lead to automatic removal of attached part and added few tests [#9410](https://github.com/ClickHouse/ClickHouse/pull/9410) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix a bug with `ON CLUSTER` DDL queries freezing on server startup. [#9927](https://github.com/ClickHouse/ClickHouse/pull/9927) ([Gagan Arneja](https://github.com/garneja))
+* Fix bug in which the necessary tables weren't retrieved at one of the processing stages of queries to some databases. Fixes [#9699](https://github.com/ClickHouse/ClickHouse/issues/9699). [#9949](https://github.com/ClickHouse/ClickHouse/pull/9949) ([achulkov2](https://github.com/achulkov2))
+* Fix 'Not found column in block' error when `JOIN` appears with `TOTALS`. Fixes [#9839](https://github.com/ClickHouse/ClickHouse/issues/9839) [#9939](https://github.com/ClickHouse/ClickHouse/pull/9939) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix parsing multiple hosts set in the CREATE USER command [#9924](https://github.com/ClickHouse/ClickHouse/pull/9924) ([Vitaly Baranov](https://github.com/vitlibar))
+* Fix `TRUNCATE` for Join table engine ([#9917](https://github.com/ClickHouse/ClickHouse/issues/9917)). [#9920](https://github.com/ClickHouse/ClickHouse/pull/9920) ([Amos Bird](https://github.com/amosbird))
+* Fix race condition between drop and optimize in `ReplicatedMergeTree`. [#9901](https://github.com/ClickHouse/ClickHouse/pull/9901) ([alesapin](https://github.com/alesapin))
+* Fix `DISTINCT` for Distributed when `optimize_skip_unused_shards` is set. [#9808](https://github.com/ClickHouse/ClickHouse/pull/9808) ([Azat Khuzhin](https://github.com/azat))
+* Fix "scalar does not exist" error in ALTERs ([#9878](https://github.com/ClickHouse/ClickHouse/issues/9878)). ... [#9904](https://github.com/ClickHouse/ClickHouse/pull/9904) ([Amos Bird](https://github.com/amosbird))
+* Fix error with qualified names in `distributed_product_mode=\'local\'`. Fixes [#4756](https://github.com/ClickHouse/ClickHouse/issues/4756) [#9891](https://github.com/ClickHouse/ClickHouse/pull/9891) ([Artem Zuikov](https://github.com/4ertus2))
+* For INSERT queries shards now do clamp the settings from the initiator to their constraints instead of throwing an exception. This fix allows to send INSERT queries to a shard with another constraints. This change improves fix [#9447](https://github.com/ClickHouse/ClickHouse/issues/9447). [#9852](https://github.com/ClickHouse/ClickHouse/pull/9852) ([Vitaly Baranov](https://github.com/vitlibar))
+* Add some retries when commiting offsets to Kafka broker, since it can reject commit if during `offsets.commit.timeout.ms` there were no enough replicas available for the `__consumer_offsets` topic [#9884](https://github.com/ClickHouse/ClickHouse/pull/9884) ([filimonov](https://github.com/filimonov))
+* Fix Distributed engine behavior when virtual columns of the underlying table used in `WHERE` [#9847](https://github.com/ClickHouse/ClickHouse/pull/9847) ([Azat Khuzhin](https://github.com/azat))
+* Fixed some cases when timezone of the function argument wasn't used properly. [#9574](https://github.com/ClickHouse/ClickHouse/pull/9574) ([Vasily Nemkov](https://github.com/Enmk))
+* Fix 'Different expressions with the same alias' error when query has PREWHERE and WHERE on distributed table and `SET distributed_product_mode = 'local'`. [#9871](https://github.com/ClickHouse/ClickHouse/pull/9871) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix mutations excessive memory consumption for tables with a composite primary key. This fixes [#9850](https://github.com/ClickHouse/ClickHouse/issues/9850). [#9860](https://github.com/ClickHouse/ClickHouse/pull/9860) ([alesapin](https://github.com/alesapin))
+* Fix calculating grants for introspection functions from the setting `allow_introspection_functions`. [#9840](https://github.com/ClickHouse/ClickHouse/pull/9840) ([Vitaly Baranov](https://github.com/vitlibar))
+* Fix max_distributed_connections (w/ and w/o Processors) [#9673](https://github.com/ClickHouse/ClickHouse/pull/9673) ([Azat Khuzhin](https://github.com/azat))
+* Fix possible exception `Got 0 in totals chunk, expected 1` on client. It happened for queries with `JOIN` in case if right joined table had zero rows. Example: `select * from system.one t1 join system.one t2 on t1.dummy = t2.dummy limit 0 FORMAT TabSeparated;`. Fixes [#9777](https://github.com/ClickHouse/ClickHouse/issues/9777). ... [#9823](https://github.com/ClickHouse/ClickHouse/pull/9823) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix 'COMMA to CROSS JOIN rewriter is not enabled or cannot rewrite query' error in case of subqueries with COMMA JOIN out of tables lists (i.e. in WHERE). Fixes [#9782](https://github.com/ClickHouse/ClickHouse/issues/9782) [#9830](https://github.com/ClickHouse/ClickHouse/pull/9830) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix server crashing when `optimize_skip_unused_shards` is set and expression for key can't be converted to its field type [#9804](https://github.com/ClickHouse/ClickHouse/pull/9804) ([Azat Khuzhin](https://github.com/azat))
+* Fix empty string handling in `splitByString`. [#9767](https://github.com/ClickHouse/ClickHouse/pull/9767) ([hcz](https://github.com/hczhcz))
+* Fix broken `ALTER TABLE DELETE COLUMN` query for compact parts. [#9779](https://github.com/ClickHouse/ClickHouse/pull/9779) ([alesapin](https://github.com/alesapin))
+* Fixed missing `rows_before_limit_at_least` for queries over http (with processors pipeline). Fixes [#9730](https://github.com/ClickHouse/ClickHouse/issues/9730) [#9757](https://github.com/ClickHouse/ClickHouse/pull/9757) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix excessive memory consumption in `ALTER` queries (mutations). This fixes [#9533](https://github.com/ClickHouse/ClickHouse/issues/9533) and [#9670](https://github.com/ClickHouse/ClickHouse/issues/9670). [#9754](https://github.com/ClickHouse/ClickHouse/pull/9754) ([alesapin](https://github.com/alesapin))
+* Fix possible permanent "Cannot schedule a task" error. [#9154](https://github.com/ClickHouse/ClickHouse/pull/9154) ([Azat Khuzhin](https://github.com/azat))
+* Fix bug in backquoting in external dictionaries DDL. Fixes [#9619](https://github.com/ClickHouse/ClickHouse/issues/9619). [#9734](https://github.com/ClickHouse/ClickHouse/pull/9734) ([alesapin](https://github.com/alesapin))
+* Fixed data race in `text_log`. It does not correspond to any real bug. [#9726](https://github.com/ClickHouse/ClickHouse/pull/9726) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix bug in a replication that does not allow replication to work if the user has executed mutations on the previous version. This fixes [#9645](https://github.com/ClickHouse/ClickHouse/issues/9645). [#9652](https://github.com/ClickHouse/ClickHouse/pull/9652) ([alesapin](https://github.com/alesapin))
+* Fixed incorrect internal function names for `sumKahan` and `sumWithOverflow`. It led to exception while using this functions in remote queries. [#9636](https://github.com/ClickHouse/ClickHouse/pull/9636) ([Azat Khuzhin](https://github.com/azat))
+* Add setting `use_compact_format_in_distributed_parts_names` which allows to write files for `INSERT` queries into `Distributed` table with more compact format. This fixes [#9647](https://github.com/ClickHouse/ClickHouse/issues/9647). [#9653](https://github.com/ClickHouse/ClickHouse/pull/9653) ([alesapin](https://github.com/alesapin))
+* Fix RIGHT and FULL JOIN with LowCardinality in JOIN keys. [#9610](https://github.com/ClickHouse/ClickHouse/pull/9610) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix possible exceptions `Size of filter does not match size of column` and `Invalid number of rows in Chunk` in `MergeTreeRangeReader`. They could appear while executing `PREWHERE` in some cases. [#9612](https://github.com/ClickHouse/ClickHouse/pull/9612) ([Anton Popov](https://github.com/CurtizJ))
+* Allow `ALTER ON CLUSTER` of Distributed tables with internal replication. This fixes [#3268](https://github.com/ClickHouse/ClickHouse/issues/3268) [#9617](https://github.com/ClickHouse/ClickHouse/pull/9617) ([shinoi2](https://github.com/shinoi2))
+* Fix issue when timezone was not preserved if you write a simple arithmetic expression like `time + 1` (in contrast to an expression like `time + INTERVAL 1 SECOND`). This fixes [#5743](https://github.com/ClickHouse/ClickHouse/issues/5743) [#9323](https://github.com/ClickHouse/ClickHouse/pull/9323) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Improvement
+* Use time zone when comparing DateTime with string literal. This fixes [#5206](https://github.com/ClickHouse/ClickHouse/issues/5206). [#10515](https://github.com/ClickHouse/ClickHouse/pull/10515) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Print verbose diagnostic info if Decimal value cannot be parsed from text input format. [#10205](https://github.com/ClickHouse/ClickHouse/pull/10205) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add tasks/memory metrics for distributed/buffer schedule pools [#10449](https://github.com/ClickHouse/ClickHouse/pull/10449) ([Azat Khuzhin](https://github.com/azat))
+* Display result as soon as it's ready for SELECT DISTINCT queries in clickhouse-local and HTTP interface. This fixes [#8951](https://github.com/ClickHouse/ClickHouse/issues/8951) [#9559](https://github.com/ClickHouse/ClickHouse/pull/9559) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Allow to use `SAMPLE OFFSET` query instead of `cityHash64(PRIMARY KEY) % N == n` for splitting in `clickhouse-copier`. To use this feature, pass `--experimental-use-sample-offset 1` as a command line argument. [#10414](https://github.com/ClickHouse/ClickHouse/pull/10414) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Allow to parse BOM in TSV if the first column cannot contain BOM in its value. This fixes [#10301](https://github.com/ClickHouse/ClickHouse/issues/10301) [#10424](https://github.com/ClickHouse/ClickHouse/pull/10424) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add Avro nested fields insert support [#10354](https://github.com/ClickHouse/ClickHouse/pull/10354) ([Andrew Onyshchuk](https://github.com/oandrew))
+* Allowed to alter column in non-modifying data mode when the same type is specified. [#10382](https://github.com/ClickHouse/ClickHouse/pull/10382) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Auto `distributed_group_by_no_merge` on GROUP BY sharding key (if `optimize_skip_unused_shards` is set) [#10341](https://github.com/ClickHouse/ClickHouse/pull/10341) ([Azat Khuzhin](https://github.com/azat))
+* Optimize queries with LIMIT/LIMIT BY/ORDER BY for distributed with GROUP BY sharding_key [#10373](https://github.com/ClickHouse/ClickHouse/pull/10373) ([Azat Khuzhin](https://github.com/azat))
+* Added a setting `max_server_memory_usage` to limit total memory usage of the server. The metric `MemoryTracking` is now calculated without a drift. The setting `max_memory_usage_for_all_queries` is now obsolete and does nothing. This closes [#10293](https://github.com/ClickHouse/ClickHouse/issues/10293). [#10362](https://github.com/ClickHouse/ClickHouse/pull/10362) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add config option `system_tables_lazy_load`. If it's set to false, then system tables with logs are loaded at the server startup. [Alexander Burmak](https://github.com/Alex-Burmak), [Svyatoslav Tkhon Il Pak](https://github.com/DeifyTheGod), [#9642](https://github.com/ClickHouse/ClickHouse/pull/9642) [#10359](https://github.com/ClickHouse/ClickHouse/pull/10359) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Use background thread pool (background_schedule_pool_size) for distributed sends [#10263](https://github.com/ClickHouse/ClickHouse/pull/10263) ([Azat Khuzhin](https://github.com/azat))
+* Use background thread pool for background buffer flushes. [#10315](https://github.com/ClickHouse/ClickHouse/pull/10315) ([Azat Khuzhin](https://github.com/azat))
+* Support for one special case of removing incompletely written parts. This fixes [#9940](https://github.com/ClickHouse/ClickHouse/issues/9940). [#10221](https://github.com/ClickHouse/ClickHouse/pull/10221) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Use isInjective() over manual list of such functions for GROUP BY optimization. [#10342](https://github.com/ClickHouse/ClickHouse/pull/10342) ([Azat Khuzhin](https://github.com/azat))
+* Avoid printing error message in log if client sends RST packet immediately on connect. It is typical behaviour of IPVS balancer with keepalived and VRRP. This fixes [#1851](https://github.com/ClickHouse/ClickHouse/issues/1851) [#10274](https://github.com/ClickHouse/ClickHouse/pull/10274) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Allow to parse `+inf` for floating point types. This closes [#1839](https://github.com/ClickHouse/ClickHouse/issues/1839) [#10272](https://github.com/ClickHouse/ClickHouse/pull/10272) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Implemented `generateRandom` table function for Nested types. This closes [#9903](https://github.com/ClickHouse/ClickHouse/issues/9903) [#10219](https://github.com/ClickHouse/ClickHouse/pull/10219) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Provide `max_allowed_packed` in MySQL compatibility interface that will help some clients to communicate with ClickHouse via MySQL protocol. [#10199](https://github.com/ClickHouse/ClickHouse/pull/10199) ([BohuTANG](https://github.com/BohuTANG))
+* Allow literals for GLOBAL IN (i.e. `SELECT * FROM remote('localhost', system.one) WHERE dummy global in (0)`) [#10196](https://github.com/ClickHouse/ClickHouse/pull/10196) ([Azat Khuzhin](https://github.com/azat))
+* Fix various small issues in interactive mode of clickhouse-client [#10194](https://github.com/ClickHouse/ClickHouse/pull/10194) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Avoid superfluous dictionaries load (system.tables, DROP/SHOW CREATE TABLE) [#10164](https://github.com/ClickHouse/ClickHouse/pull/10164) ([Azat Khuzhin](https://github.com/azat))
+* Update to RWLock: timeout parameter for getLock() + implementation reworked to be phase fair [#10073](https://github.com/ClickHouse/ClickHouse/pull/10073) ([Alexander Kazakov](https://github.com/Akazz))
+* Enhanced compatibility with native mysql-connector-java(JDBC) [#10021](https://github.com/ClickHouse/ClickHouse/pull/10021) ([BohuTANG](https://github.com/BohuTANG))
+* The function `toString` is considered monotonic and can be used for index analysis even when applied in tautological cases with String or LowCardinality(String) argument. [#10110](https://github.com/ClickHouse/ClickHouse/pull/10110) ([Amos Bird](https://github.com/amosbird))
+* Add `ON CLUSTER` clause support to commands `{CREATE|DROP} USER/ROLE/ROW POLICY/SETTINGS PROFILE/QUOTA`, `GRANT`. [#9811](https://github.com/ClickHouse/ClickHouse/pull/9811) ([Vitaly Baranov](https://github.com/vitlibar))
+* Virtual hosted-style support for S3 URI [#9998](https://github.com/ClickHouse/ClickHouse/pull/9998) ([Pavel Kovalenko](https://github.com/Jokser))
+* Now layout type for dictionaries with no arguments can be specified without round brackets in dictionaries DDL-queries. Fixes [#10057](https://github.com/ClickHouse/ClickHouse/issues/10057). [#10064](https://github.com/ClickHouse/ClickHouse/pull/10064) ([alesapin](https://github.com/alesapin))
+* Add ability to use number ranges with leading zeros in filepath [#9989](https://github.com/ClickHouse/ClickHouse/pull/9989) ([Olga Khvostikova](https://github.com/stavrolia))
+* Better memory usage in CROSS JOIN. [#10029](https://github.com/ClickHouse/ClickHouse/pull/10029) ([Artem Zuikov](https://github.com/4ertus2))
+* Try to connect to all shards in cluster when getting structure of remote table and skip_unavailable_shards is set. [#7278](https://github.com/ClickHouse/ClickHouse/pull/7278) ([nvartolomei](https://github.com/nvartolomei))
+* Add `total_rows`/`total_bytes` into the `system.tables` table. [#9919](https://github.com/ClickHouse/ClickHouse/pull/9919) ([Azat Khuzhin](https://github.com/azat))
+* System log tables now use polymorpic parts by default. [#9905](https://github.com/ClickHouse/ClickHouse/pull/9905) ([Anton Popov](https://github.com/CurtizJ))
+* Add type column into system.settings/merge_tree_settings [#9909](https://github.com/ClickHouse/ClickHouse/pull/9909) ([Azat Khuzhin](https://github.com/azat))
+* Check for available CPU instructions at server startup as early as possible. [#9888](https://github.com/ClickHouse/ClickHouse/pull/9888) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Remove `ORDER BY` stage from mutations because we read from a single ordered part in a single thread. Also add check that the rows in mutation are ordered by sorting key and this order is not violated. [#9886](https://github.com/ClickHouse/ClickHouse/pull/9886) ([alesapin](https://github.com/alesapin))
+* Implement operator LIKE for FixedString at left hand side. This is needed to better support TPC-DS queries. [#9890](https://github.com/ClickHouse/ClickHouse/pull/9890) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add `force_optimize_skip_unused_shards_no_nested` that will disable `force_optimize_skip_unused_shards` for nested Distributed table [#9812](https://github.com/ClickHouse/ClickHouse/pull/9812) ([Azat Khuzhin](https://github.com/azat))
+* Now columns size is calculated only once for MergeTree data parts. [#9827](https://github.com/ClickHouse/ClickHouse/pull/9827) ([alesapin](https://github.com/alesapin))
+* Evaluate constant expressions for `optimize_skip_unused_shards` (i.e. `SELECT * FROM foo_dist WHERE key=xxHash32(0)`) [#8846](https://github.com/ClickHouse/ClickHouse/pull/8846) ([Azat Khuzhin](https://github.com/azat))
+* Check for using `Date` or `DateTime` column from TTL expressions was removed. [#9967](https://github.com/ClickHouse/ClickHouse/pull/9967) ([Vladimir Chebotarev](https://github.com/excitoon))
+* DiskS3 hard links optimal implementation. [#9760](https://github.com/ClickHouse/ClickHouse/pull/9760) ([Pavel Kovalenko](https://github.com/Jokser))
+* If `set multiple_joins_rewriter_version = 2` enables second version of multiple JOIN rewrites that keeps not clashed column names as is. It supports multiple JOINs with `USING` and allow `select *` for JOINs with subqueries. [#9739](https://github.com/ClickHouse/ClickHouse/pull/9739) ([Artem Zuikov](https://github.com/4ertus2))
+* Implementation of "non-blocking" alter for StorageMergeTree [#9606](https://github.com/ClickHouse/ClickHouse/pull/9606) ([alesapin](https://github.com/alesapin))
+* Add MergeTree full support for DiskS3 [#9646](https://github.com/ClickHouse/ClickHouse/pull/9646) ([Pavel Kovalenko](https://github.com/Jokser))
+* Extend `splitByString` to support empty strings as separators. [#9742](https://github.com/ClickHouse/ClickHouse/pull/9742) ([hcz](https://github.com/hczhcz))
+* Add a `timestamp_ns` column to `system.trace_log`. It contains a high-definition timestamp of the trace event, and allows to build timelines of thread profiles ("flame charts"). [#9696](https://github.com/ClickHouse/ClickHouse/pull/9696) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* When the setting `send_logs_level` is enabled, avoid intermixing of log messages and query progress. [#9634](https://github.com/ClickHouse/ClickHouse/pull/9634) ([Azat Khuzhin](https://github.com/azat))
+* Added support of `MATERIALIZE TTL IN PARTITION`. [#9581](https://github.com/ClickHouse/ClickHouse/pull/9581) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Support complex types inside Avro nested fields [#10502](https://github.com/ClickHouse/ClickHouse/pull/10502) ([Andrew Onyshchuk](https://github.com/oandrew))
+
+#### Performance Improvement
+* Better insert logic for right table for Partial MergeJoin. [#10467](https://github.com/ClickHouse/ClickHouse/pull/10467) ([Artem Zuikov](https://github.com/4ertus2))
+* Improved performance of row-oriented formats (more than 10% for CSV and more than 35% for Avro in case of narrow tables). [#10503](https://github.com/ClickHouse/ClickHouse/pull/10503) ([Andrew Onyshchuk](https://github.com/oandrew))
+* Improved performance of queries with explicitly defined sets at right side of IN operator and tuples on the left side. [#10385](https://github.com/ClickHouse/ClickHouse/pull/10385) ([Anton Popov](https://github.com/CurtizJ))
+* Use less memory for hash table in HashJoin. [#10416](https://github.com/ClickHouse/ClickHouse/pull/10416) ([Artem Zuikov](https://github.com/4ertus2))
+* Special HashJoin over StorageDictionary. Allow rewrite `dictGet()` functions with JOINs. It's not backward incompatible itself but could uncover [#8400](https://github.com/ClickHouse/ClickHouse/issues/8400) on some installations. [#10133](https://github.com/ClickHouse/ClickHouse/pull/10133) ([Artem Zuikov](https://github.com/4ertus2))
+* Enable parallel insert of materialized view when its target table supports. [#10052](https://github.com/ClickHouse/ClickHouse/pull/10052) ([vxider](https://github.com/Vxider))
+* Improved performance of index analysis with monotonic functions. [#9607](https://github.com/ClickHouse/ClickHouse/pull/9607)[#10026](https://github.com/ClickHouse/ClickHouse/pull/10026) ([Anton Popov](https://github.com/CurtizJ))
+* Using SSE2 or SSE4.2 SIMD intrinsics to speed up tokenization in bloom filters. [#9968](https://github.com/ClickHouse/ClickHouse/pull/9968) ([Vasily Nemkov](https://github.com/Enmk))
+* Improved performance of queries with explicitly defined sets at right side of `IN` operator. This fixes performance regression in version 20.3. [#9740](https://github.com/ClickHouse/ClickHouse/pull/9740) ([Anton Popov](https://github.com/CurtizJ))
+* Now clickhouse-copier splits each partition in number of pieces and copies them independently. [#9075](https://github.com/ClickHouse/ClickHouse/pull/9075) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Adding more aggregation methods. For example TPC-H query 1 will now pick `FixedHashMap<UInt16, AggregateDataPtr>` and gets 25% performance gain [#9829](https://github.com/ClickHouse/ClickHouse/pull/9829) ([Amos Bird](https://github.com/amosbird))
+* Use single row counter for multiple streams in pre-limit transform. This helps to avoid uniting pipeline streams in queries with `limit` but without `order by` (like `select f(x) from (select x from t limit 1000000000)`) and use multiple threads for further processing. [#9602](https://github.com/ClickHouse/ClickHouse/pull/9602) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+
+#### Build/Testing/Packaging Improvement
+* Use a fork of AWS SDK libraries from ClickHouse-Extras [#10527](https://github.com/ClickHouse/ClickHouse/pull/10527) ([Pavel Kovalenko](https://github.com/Jokser))
+* Add integration tests for new ALTER RENAME COLUMN query. [#10654](https://github.com/ClickHouse/ClickHouse/pull/10654) ([vzakaznikov](https://github.com/vzakaznikov))
+* Fix possible signed integer overflow in invocation of function `now64` with wrong arguments. This fixes [#8973](https://github.com/ClickHouse/ClickHouse/issues/8973) [#10511](https://github.com/ClickHouse/ClickHouse/pull/10511) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Split fuzzer and sanitizer configurations to make build config compatible with Oss-fuzz. [#10494](https://github.com/ClickHouse/ClickHouse/pull/10494) ([kyprizel](https://github.com/kyprizel))
+* Fixes for clang-tidy on clang-10. [#10420](https://github.com/ClickHouse/ClickHouse/pull/10420) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Display absolute paths in error messages. Otherwise KDevelop fails to navigate to correct file and opens a new file instead. [#10434](https://github.com/ClickHouse/ClickHouse/pull/10434) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added `ASAN_OPTIONS` environment variable to investigate errors in CI stress tests with Address sanitizer. [#10440](https://github.com/ClickHouse/ClickHouse/pull/10440) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Enable ThinLTO for clang builds (experimental). [#10435](https://github.com/ClickHouse/ClickHouse/pull/10435) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Remove accidential dependency on Z3 that may be introduced if the system has Z3 solver installed. [#10426](https://github.com/ClickHouse/ClickHouse/pull/10426) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Move integration tests docker files to docker/ directory. [#10335](https://github.com/ClickHouse/ClickHouse/pull/10335) ([Ilya Yatsishin](https://github.com/qoega))
+* Allow to use `clang-10` in CI. It ensures that [#10238](https://github.com/ClickHouse/ClickHouse/issues/10238) is fixed. [#10384](https://github.com/ClickHouse/ClickHouse/pull/10384) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Update OpenSSL to upstream master. Fixed the issue when TLS connections may fail with the message `OpenSSL SSL_read: error:14094438:SSL routines:ssl3_read_bytes:tlsv1 alert internal error` and `SSL Exception: error:2400006E:random number generator::error retrieving entropy`. The issue was present in version 20.1. [#8956](https://github.com/ClickHouse/ClickHouse/pull/8956) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix clang-10 build. [#10238](https://github.com/ClickHouse/ClickHouse/issues/10238) [#10370](https://github.com/ClickHouse/ClickHouse/pull/10370) ([Amos Bird](https://github.com/amosbird))
+* Add performance test for [Parallel INSERT for materialized view](https://github.com/ClickHouse/ClickHouse/pull/10052). [#10345](https://github.com/ClickHouse/ClickHouse/pull/10345) ([vxider](https://github.com/Vxider))
+* Fix flaky test `test_settings_constraints_distributed.test_insert_clamps_settings`. [#10346](https://github.com/ClickHouse/ClickHouse/pull/10346) ([Vitaly Baranov](https://github.com/vitlibar))
+* Add util to test results upload in CI ClickHouse [#10330](https://github.com/ClickHouse/ClickHouse/pull/10330) ([Ilya Yatsishin](https://github.com/qoega))
+* Convert test results to JSONEachRow format in junit_to_html tool [#10323](https://github.com/ClickHouse/ClickHouse/pull/10323) ([Ilya Yatsishin](https://github.com/qoega))
+* Update cctz. [#10215](https://github.com/ClickHouse/ClickHouse/pull/10215) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Allow to create HTML report from the purest JUnit XML report. [#10247](https://github.com/ClickHouse/ClickHouse/pull/10247) ([Ilya Yatsishin](https://github.com/qoega))
+* Update the check for minimal compiler version. Fix the root cause of the issue [#10250](https://github.com/ClickHouse/ClickHouse/issues/10250) [#10256](https://github.com/ClickHouse/ClickHouse/pull/10256) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Initial support for live view tables over distributed [#10179](https://github.com/ClickHouse/ClickHouse/pull/10179) ([vzakaznikov](https://github.com/vzakaznikov))
+* Fix (false) MSan report in MergeTreeIndexFullText. The issue first appeared in [#9968](https://github.com/ClickHouse/ClickHouse/issues/9968). [#10801](https://github.com/ClickHouse/ClickHouse/pull/10801) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* clickhouse-docker-util [#10151](https://github.com/ClickHouse/ClickHouse/pull/10151) ([filimonov](https://github.com/filimonov))
+* Update pdqsort to recent version [#10171](https://github.com/ClickHouse/ClickHouse/pull/10171) ([Ivan](https://github.com/abyss7))
+* Update libdivide to v3.0 [#10169](https://github.com/ClickHouse/ClickHouse/pull/10169) ([Ivan](https://github.com/abyss7))
+* Add check with enabled polymorphic parts. [#10086](https://github.com/ClickHouse/ClickHouse/pull/10086) ([Anton Popov](https://github.com/CurtizJ))
+* Add cross-compile build for FreeBSD. This fixes [#9465](https://github.com/ClickHouse/ClickHouse/issues/9465) [#9643](https://github.com/ClickHouse/ClickHouse/pull/9643) ([Ivan](https://github.com/abyss7))
+* Add performance test for [#6924](https://github.com/ClickHouse/ClickHouse/issues/6924) [#6980](https://github.com/ClickHouse/ClickHouse/pull/6980) ([filimonov](https://github.com/filimonov))
+* Add support of `/dev/null` in the `File` engine for better performance testing [#8455](https://github.com/ClickHouse/ClickHouse/pull/8455) ([Amos Bird](https://github.com/amosbird))
+* Move all folders inside /dbms one level up [#9974](https://github.com/ClickHouse/ClickHouse/pull/9974) ([Ivan](https://github.com/abyss7))
+* Add a test that checks that read from MergeTree with single thread is performed in order. Addition to [#9670](https://github.com/ClickHouse/ClickHouse/issues/9670) [#9762](https://github.com/ClickHouse/ClickHouse/pull/9762) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix the `00964_live_view_watch_events_heartbeat.py` test to avoid race condition. [#9944](https://github.com/ClickHouse/ClickHouse/pull/9944) ([vzakaznikov](https://github.com/vzakaznikov))
+* Fix integration test `test_settings_constraints` [#9962](https://github.com/ClickHouse/ClickHouse/pull/9962) ([Vitaly Baranov](https://github.com/vitlibar))
+* Every function in its own file, part 12. [#9922](https://github.com/ClickHouse/ClickHouse/pull/9922) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added performance test for the case of extremely slow analysis of array of tuples. [#9872](https://github.com/ClickHouse/ClickHouse/pull/9872) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Update zstd to 1.4.4. It has some minor improvements in performance and compression ratio. If you run replicas with different versions of ClickHouse you may see reasonable error messages `Data after merge is not byte-identical to data on another replicas.` with explanation. These messages are Ok and you should not worry. [#10663](https://github.com/ClickHouse/ClickHouse/pull/10663) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix TSan report in `system.stack_trace`. [#9832](https://github.com/ClickHouse/ClickHouse/pull/9832) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Removed dependency on `clock_getres`. [#9833](https://github.com/ClickHouse/ClickHouse/pull/9833) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added identifier names check with clang-tidy. [#9799](https://github.com/ClickHouse/ClickHouse/pull/9799) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Update "builder" docker image. This image is not used in CI but is useful for developers. [#9809](https://github.com/ClickHouse/ClickHouse/pull/9809) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Remove old `performance-test` tool that is no longer used in CI. `clickhouse-performance-test` is great but now we are using way superior tool that is doing comparison testing with sophisticated statistical formulas to achieve confident results regardless to various changes in environment. [#9796](https://github.com/ClickHouse/ClickHouse/pull/9796) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added most of clang-static-analyzer checks. [#9765](https://github.com/ClickHouse/ClickHouse/pull/9765) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Update Poco to 1.9.3 in preparation for MongoDB URI support. [#6892](https://github.com/ClickHouse/ClickHouse/pull/6892) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Fix build with `-DUSE_STATIC_LIBRARIES=0 -DENABLE_JEMALLOC=0` [#9651](https://github.com/ClickHouse/ClickHouse/pull/9651) ([Artem Zuikov](https://github.com/4ertus2))
+* For change log script, if merge commit was cherry-picked to release branch, take PR name from commit description. [#9708](https://github.com/ClickHouse/ClickHouse/pull/9708) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Support `vX.X-conflicts` tag in backport script. [#9705](https://github.com/ClickHouse/ClickHouse/pull/9705) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix `auto-label` for backporting script. [#9685](https://github.com/ClickHouse/ClickHouse/pull/9685) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Use libc++ in Darwin cross-build to make it consistent with native build. [#9665](https://github.com/ClickHouse/ClickHouse/pull/9665) ([Hui Wang](https://github.com/huiwang))
+* Fix flacky test `01017_uniqCombined_memory_usage`. Continuation of [#7236](https://github.com/ClickHouse/ClickHouse/issues/7236). [#9667](https://github.com/ClickHouse/ClickHouse/pull/9667) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix build for native MacOS Clang compiler [#9649](https://github.com/ClickHouse/ClickHouse/pull/9649) ([Ivan](https://github.com/abyss7))
+* Allow to add various glitches around `pthread_mutex_lock`, `pthread_mutex_unlock` functions. [#9635](https://github.com/ClickHouse/ClickHouse/pull/9635) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add support for `clang-tidy` in `packager` script. [#9625](https://github.com/ClickHouse/ClickHouse/pull/9625) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add ability to use unbundled msgpack. [#10168](https://github.com/ClickHouse/ClickHouse/pull/10168) ([Azat Khuzhin](https://github.com/azat))
+
+
+## ClickHouse release v20.3
+
+
+### ClickHouse release v20.3.21.2-lts, 2020-11-02
+
+#### Bug Fix
+
+* Fix dictGet in sharding_key (and similar places, i.e. when the function context is stored permanently). [#16205](https://github.com/ClickHouse/ClickHouse/pull/16205) ([Azat Khuzhin](https://github.com/azat)).
+* Fix incorrect empty result for query from `Distributed` table if query has `WHERE`, `PREWHERE` and `GLOBAL IN`. Fixes [#15792](https://github.com/ClickHouse/ClickHouse/issues/15792). [#15933](https://github.com/ClickHouse/ClickHouse/pull/15933) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix missing or excessive headers in `TSV/CSVWithNames` formats. This fixes [#12504](https://github.com/ClickHouse/ClickHouse/issues/12504). [#13343](https://github.com/ClickHouse/ClickHouse/pull/13343) ([Azat Khuzhin](https://github.com/azat)).
+
+
+### ClickHouse release v20.3.20.6-lts, 2020-10-09
+
+#### Bug Fix
+
+* Mutation might hang waiting for some non-existent part after `MOVE` or `REPLACE PARTITION` or, in rare cases, after `DETACH` or `DROP PARTITION`. It's fixed. [#15724](https://github.com/ClickHouse/ClickHouse/pull/15724), [#15537](https://github.com/ClickHouse/ClickHouse/pull/15537) ([tavplubix](https://github.com/tavplubix)).
+* Fix hang of queries with a lot of subqueries to same table of `MySQL` engine. Previously, if there were more than 16 subqueries to same `MySQL` table in query, it hang forever. [#15299](https://github.com/ClickHouse/ClickHouse/pull/15299) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix 'Unknown identifier' in GROUP BY when query has JOIN over Merge table. [#15242](https://github.com/ClickHouse/ClickHouse/pull/15242) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix to make predicate push down work when subquery contains finalizeAggregation function. Fixes [#14847](https://github.com/ClickHouse/ClickHouse/issues/14847). [#14937](https://github.com/ClickHouse/ClickHouse/pull/14937) ([filimonov](https://github.com/filimonov)).
+* Concurrent `ALTER ... REPLACE/MOVE PARTITION ...` queries might cause deadlock. It's fixed. [#13626](https://github.com/ClickHouse/ClickHouse/pull/13626) ([tavplubix](https://github.com/tavplubix)).
+
+
+### ClickHouse release v20.3.19.4-lts, 2020-09-18
+
+#### Bug Fix
+
+* Fix rare error in `SELECT` queries when the queried column has `DEFAULT` expression which depends on the other column which also has `DEFAULT` and not present in select query and not exists on disk. Partially fixes [#14531](https://github.com/ClickHouse/ClickHouse/issues/14531). [#14845](https://github.com/ClickHouse/ClickHouse/pull/14845) ([alesapin](https://github.com/alesapin)).
+* Fix bug when `ALTER UPDATE` mutation with Nullable column in assignment expression and constant value (like `UPDATE x = 42`) leads to incorrect value in column or segfault. Fixes [#13634](https://github.com/ClickHouse/ClickHouse/issues/13634), [#14045](https://github.com/ClickHouse/ClickHouse/issues/14045). [#14646](https://github.com/ClickHouse/ClickHouse/pull/14646) ([alesapin](https://github.com/alesapin)).
+* Fix wrong Decimal multiplication result caused wrong decimal scale of result column. [#14603](https://github.com/ClickHouse/ClickHouse/pull/14603) ([Artem Zuikov](https://github.com/4ertus2)).
+
+#### Improvement
+
+* Support custom codecs in compact parts. [#12183](https://github.com/ClickHouse/ClickHouse/pull/12183) ([Anton Popov](https://github.com/CurtizJ)).
+
+
+### ClickHouse release v20.3.18.10-lts, 2020-09-08
+
+#### Bug Fix
+
+* Stop query execution if exception happened in `PipelineExecutor` itself. This could prevent rare possible query hung. Continuation of [#14334](https://github.com/ClickHouse/ClickHouse/issues/14334). [#14402](https://github.com/ClickHouse/ClickHouse/pull/14402) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed the behaviour when sometimes cache-dictionary returned default value instead of present value from source. [#13624](https://github.com/ClickHouse/ClickHouse/pull/13624) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix parsing row policies from users.xml when names of databases or tables contain dots. This fixes [#5779](https://github.com/ClickHouse/ClickHouse/issues/5779), [#12527](https://github.com/ClickHouse/ClickHouse/issues/12527). [#13199](https://github.com/ClickHouse/ClickHouse/pull/13199) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix CAST(Nullable(String), Enum()). [#12745](https://github.com/ClickHouse/ClickHouse/pull/12745) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed data race in `text_log`. It does not correspond to any real bug. [#9726](https://github.com/ClickHouse/ClickHouse/pull/9726) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### Improvement
+
+* Fix wrong error for long queries. It was possible to get syntax error other than `Max query size exceeded` for correct query. [#13928](https://github.com/ClickHouse/ClickHouse/pull/13928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Return NULL/zero when value is not parsed completely in parseDateTimeBestEffortOrNull/Zero functions. This fixes [#7876](https://github.com/ClickHouse/ClickHouse/issues/7876). [#11653](https://github.com/ClickHouse/ClickHouse/pull/11653) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### Performance Improvement
+
+* Slightly optimize very short queries with LowCardinality. [#14129](https://github.com/ClickHouse/ClickHouse/pull/14129) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Build/Testing/Packaging Improvement
+
+* Fix UBSan report (adding zero to nullptr) in HashTable that appeared after migration to clang-10. [#10638](https://github.com/ClickHouse/ClickHouse/pull/10638) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+
+### ClickHouse release v20.3.17.173-lts, 2020-08-15
+
+#### Bug Fix
+
+* Fix crash in JOIN with StorageMerge and `set enable_optimize_predicate_expression=1`. [#13679](https://github.com/ClickHouse/ClickHouse/pull/13679) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix invalid return type for comparison of tuples with `NULL` elements. Fixes [#12461](https://github.com/ClickHouse/ClickHouse/issues/12461). [#13420](https://github.com/ClickHouse/ClickHouse/pull/13420) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix queries with constant columns and `ORDER BY` prefix of primary key. [#13396](https://github.com/ClickHouse/ClickHouse/pull/13396) ([Anton Popov](https://github.com/CurtizJ)).
+* Return passed number for numbers with MSB set in roundUpToPowerOfTwoOrZero(). [#13234](https://github.com/ClickHouse/ClickHouse/pull/13234) ([Azat Khuzhin](https://github.com/azat)).
+
+
+### ClickHouse release v20.3.16.165-lts 2020-08-10
+
+#### Bug Fix
+
+* Fixed error in `parseDateTimeBestEffort` function when unix timestamp was passed as an argument. This fixes [#13362](https://github.com/ClickHouse/ClickHouse/issues/13362). [#13441](https://github.com/ClickHouse/ClickHouse/pull/13441) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potentially low performance and slightly incorrect result for `uniqExact`, `topK`, `sumDistinct` and similar aggregate functions called on Float types with `NaN` values. It also triggered assert in debug build. This fixes [#12491](https://github.com/ClickHouse/ClickHouse/issues/12491). [#13254](https://github.com/ClickHouse/ClickHouse/pull/13254) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed function if with nullable constexpr as cond that is not literal NULL. Fixes [#12463](https://github.com/ClickHouse/ClickHouse/issues/12463). [#13226](https://github.com/ClickHouse/ClickHouse/pull/13226) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed assert in `arrayElement` function in case of array elements are Nullable and array subscript is also Nullable. This fixes [#12172](https://github.com/ClickHouse/ClickHouse/issues/12172). [#13224](https://github.com/ClickHouse/ClickHouse/pull/13224) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed unnecessary limiting for the number of threads for selects from local replica. [#12840](https://github.com/ClickHouse/ClickHouse/pull/12840) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed possible extra overflow row in data which could appear for queries `WITH TOTALS`. [#12747](https://github.com/ClickHouse/ClickHouse/pull/12747) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed performance with large tuples, which are interpreted as functions in `IN` section. The case when user write `WHERE x IN tuple(1, 2, ...)` instead of `WHERE x IN (1, 2, ...)` for some obscure reason. [#12700](https://github.com/ClickHouse/ClickHouse/pull/12700) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed memory tracking for input_format_parallel_parsing (by attaching thread to group). [#12672](https://github.com/ClickHouse/ClickHouse/pull/12672) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed [#12293](https://github.com/ClickHouse/ClickHouse/issues/12293) allow push predicate when subquery contains with clause. [#12663](https://github.com/ClickHouse/ClickHouse/pull/12663) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed [#10572](https://github.com/ClickHouse/ClickHouse/issues/10572) fix bloom filter index with const expression. [#12659](https://github.com/ClickHouse/ClickHouse/pull/12659) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed SIGSEGV in StorageKafka when broker is unavailable (and not only). [#12658](https://github.com/ClickHouse/ClickHouse/pull/12658) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed race condition in external dictionaries with cache layout which can lead server crash. [#12566](https://github.com/ClickHouse/ClickHouse/pull/12566) ([alesapin](https://github.com/alesapin)).
+* Fixed bug which lead to broken old parts after `ALTER DELETE` query when `enable_mixed_granularity_parts=1`. Fixes [#12536](https://github.com/ClickHouse/ClickHouse/issues/12536). [#12543](https://github.com/ClickHouse/ClickHouse/pull/12543) ([alesapin](https://github.com/alesapin)).
+* Better exception for function `in` with invalid number of arguments. [#12529](https://github.com/ClickHouse/ClickHouse/pull/12529) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed performance issue, while reading from compact parts. [#12492](https://github.com/ClickHouse/ClickHouse/pull/12492) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed the deadlock if `text_log` is enabled. [#12452](https://github.com/ClickHouse/ClickHouse/pull/12452) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed possible segfault if StorageMerge. Closes [#12054](https://github.com/ClickHouse/ClickHouse/issues/12054). [#12401](https://github.com/ClickHouse/ClickHouse/pull/12401) ([tavplubix](https://github.com/tavplubix)).
+* Fixed `TOTALS/ROLLUP/CUBE` for aggregate functions with `-State` and `Nullable` arguments. This fixes [#12163](https://github.com/ClickHouse/ClickHouse/issues/12163). [#12376](https://github.com/ClickHouse/ClickHouse/pull/12376) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed order of columns in `WITH FILL` modifier. Previously order of columns of `ORDER BY` statement wasn't respected. [#12306](https://github.com/ClickHouse/ClickHouse/pull/12306) ([Anton Popov](https://github.com/CurtizJ)).
+* Avoid "bad cast" exception when there is an expression that filters data by virtual columns (like `_table` in `Merge` tables) or by "index" columns in system tables such as filtering by database name when querying from `system.tables`, and this expression returns `Nullable` type. This fixes [#12166](https://github.com/ClickHouse/ClickHouse/issues/12166). [#12305](https://github.com/ClickHouse/ClickHouse/pull/12305) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Show error after `TrieDictionary` failed to load. [#12290](https://github.com/ClickHouse/ClickHouse/pull/12290) ([Vitaly Baranov](https://github.com/vitlibar)).
+* The function `arrayFill` worked incorrectly for empty arrays that may lead to crash. This fixes [#12263](https://github.com/ClickHouse/ClickHouse/issues/12263). [#12279](https://github.com/ClickHouse/ClickHouse/pull/12279) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Implement conversions to the common type for `LowCardinality` types. This allows to execute UNION ALL of tables with columns of LowCardinality and other columns. This fixes [#8212](https://github.com/ClickHouse/ClickHouse/issues/8212). This fixes [#4342](https://github.com/ClickHouse/ClickHouse/issues/4342). [#12275](https://github.com/ClickHouse/ClickHouse/pull/12275) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the behaviour when during multiple sequential inserts in `StorageFile` header for some special types was written more than once. This fixed [#6155](https://github.com/ClickHouse/ClickHouse/issues/6155). [#12197](https://github.com/ClickHouse/ClickHouse/pull/12197) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed logical functions for UInt8 values when they are not equal to 0 or 1. [#12196](https://github.com/ClickHouse/ClickHouse/pull/12196) ([Alexander Kazakov](https://github.com/Akazz)).
+* Fixed `dictGet` arguments check during GROUP BY injective functions elimination. [#12179](https://github.com/ClickHouse/ClickHouse/pull/12179) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed wrong logic in `ALTER DELETE` that leads to deleting of records when condition evaluates to NULL. This fixes [#9088](https://github.com/ClickHouse/ClickHouse/issues/9088). This closes [#12106](https://github.com/ClickHouse/ClickHouse/issues/12106). [#12153](https://github.com/ClickHouse/ClickHouse/pull/12153) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed transform of query to send to external DBMS (e.g. MySQL, ODBC) in presense of aliases. This fixes [#12032](https://github.com/ClickHouse/ClickHouse/issues/12032). [#12151](https://github.com/ClickHouse/ClickHouse/pull/12151) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential overflow in integer division. This fixes [#12119](https://github.com/ClickHouse/ClickHouse/issues/12119). [#12140](https://github.com/ClickHouse/ClickHouse/pull/12140) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential infinite loop in `greatCircleDistance`, `geoDistance`. This fixes [#12117](https://github.com/ClickHouse/ClickHouse/issues/12117). [#12137](https://github.com/ClickHouse/ClickHouse/pull/12137) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Avoid `There is no query` exception for materialized views with joins or with subqueries attached to system logs (system.query_log, metric_log, etc) or to engine=Buffer underlying table. [#12120](https://github.com/ClickHouse/ClickHouse/pull/12120) ([filimonov](https://github.com/filimonov)).
+* Fixed performance for selects with `UNION` caused by wrong limit for the total number of threads. Fixes [#12030](https://github.com/ClickHouse/ClickHouse/issues/12030). [#12103](https://github.com/ClickHouse/ClickHouse/pull/12103) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed segfault with `-StateResample` combinators. [#12092](https://github.com/ClickHouse/ClickHouse/pull/12092) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed unnecessary limiting the number of threads for selects from `VIEW`. Fixes [#11937](https://github.com/ClickHouse/ClickHouse/issues/11937). [#12085](https://github.com/ClickHouse/ClickHouse/pull/12085) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed possible crash while using wrong type for `PREWHERE`. Fixes [#12053](https://github.com/ClickHouse/ClickHouse/issues/12053), [#12060](https://github.com/ClickHouse/ClickHouse/issues/12060). [#12060](https://github.com/ClickHouse/ClickHouse/pull/12060) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed error `Expected single dictionary argument for function` for function `defaultValueOfArgumentType` with `LowCardinality` type. Fixes [#11808](https://github.com/ClickHouse/ClickHouse/issues/11808). [#12056](https://github.com/ClickHouse/ClickHouse/pull/12056) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed error `Cannot capture column` for higher-order functions with `Tuple(LowCardinality)` argument. Fixes [#9766](https://github.com/ClickHouse/ClickHouse/issues/9766). [#12055](https://github.com/ClickHouse/ClickHouse/pull/12055) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Parse tables metadata in parallel when loading database. This fixes slow server startup when there are large number of tables. [#12045](https://github.com/ClickHouse/ClickHouse/pull/12045) ([tavplubix](https://github.com/tavplubix)).
+* Make `topK` aggregate function return Enum for Enum types. This fixes [#3740](https://github.com/ClickHouse/ClickHouse/issues/3740). [#12043](https://github.com/ClickHouse/ClickHouse/pull/12043) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed constraints check if constraint is a constant expression. This fixes [#11360](https://github.com/ClickHouse/ClickHouse/issues/11360). [#12042](https://github.com/ClickHouse/ClickHouse/pull/12042) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed incorrect comparison of tuples with `Nullable` columns. Fixes [#11985](https://github.com/ClickHouse/ClickHouse/issues/11985). [#12039](https://github.com/ClickHouse/ClickHouse/pull/12039) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed wrong result and potential crash when invoking function `if` with arguments of type `FixedString` with different sizes. This fixes [#11362](https://github.com/ClickHouse/ClickHouse/issues/11362). [#12021](https://github.com/ClickHouse/ClickHouse/pull/12021) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* A query with function `neighbor` as the only returned expression may return empty result if the function is called with offset `-9223372036854775808`. This fixes [#11367](https://github.com/ClickHouse/ClickHouse/issues/11367). [#12019](https://github.com/ClickHouse/ClickHouse/pull/12019) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential array size overflow in generateRandom that may lead to crash. This fixes [#11371](https://github.com/ClickHouse/ClickHouse/issues/11371). [#12013](https://github.com/ClickHouse/ClickHouse/pull/12013) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential floating point exception. This closes [#11378](https://github.com/ClickHouse/ClickHouse/issues/11378). [#12005](https://github.com/ClickHouse/ClickHouse/pull/12005) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed wrong setting name in log message at server startup. [#11997](https://github.com/ClickHouse/ClickHouse/pull/11997) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `Query parameter was not set` in `Values` format. Fixes [#11918](https://github.com/ClickHouse/ClickHouse/issues/11918). [#11936](https://github.com/ClickHouse/ClickHouse/pull/11936) ([tavplubix](https://github.com/tavplubix)).
+* Keep aliases for substitutions in query (parametrized queries). This fixes [#11914](https://github.com/ClickHouse/ClickHouse/issues/11914). [#11916](https://github.com/ClickHouse/ClickHouse/pull/11916) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed potential floating point exception when parsing DateTime64. This fixes [#11374](https://github.com/ClickHouse/ClickHouse/issues/11374). [#11875](https://github.com/ClickHouse/ClickHouse/pull/11875) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed memory accounting via `HTTP` interface (can be significant with `wait_end_of_query=1`). [#11840](https://github.com/ClickHouse/ClickHouse/pull/11840) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed wrong result for `if()` with NULLs in condition. [#11807](https://github.com/ClickHouse/ClickHouse/pull/11807) ([Artem Zuikov](https://github.com/4ertus2)).
+* Parse metadata stored in zookeeper before checking for equality. [#11739](https://github.com/ClickHouse/ClickHouse/pull/11739) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed `LIMIT n WITH TIES` usage together with `ORDER BY` statement, which contains aliases. [#11689](https://github.com/ClickHouse/ClickHouse/pull/11689) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix potential read of uninitialized memory in cache dictionary. [#10834](https://github.com/ClickHouse/ClickHouse/pull/10834) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### Performance Improvement
+
+* Index not used for IN operator with literals, performance regression introduced around v19.3. This fixes [#10574](https://github.com/ClickHouse/ClickHouse/issues/10574). [#12062](https://github.com/ClickHouse/ClickHouse/pull/12062) ([nvartolomei](https://github.com/nvartolomei)).
+
+
+### ClickHouse release v20.3.12.112-lts 2020-06-25
+
+#### Bug Fix
+
+* Fix rare crash caused by using `Nullable` column in prewhere condition. Continuation of [#11608](https://github.com/ClickHouse/ClickHouse/issues/11608). [#11869](https://github.com/ClickHouse/ClickHouse/pull/11869) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Don't allow arrayJoin inside higher order functions. It was leading to broken protocol synchronization. This closes [#3933](https://github.com/ClickHouse/ClickHouse/issues/3933). [#11846](https://github.com/ClickHouse/ClickHouse/pull/11846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix using too many threads for queries. [#11788](https://github.com/ClickHouse/ClickHouse/pull/11788) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix unexpected behaviour of queries like `SELECT *, xyz.*` which were success while an error expected. [#11753](https://github.com/ClickHouse/ClickHouse/pull/11753) ([hexiaoting](https://github.com/hexiaoting)).
+* Now replicated fetches will be cancelled during metadata alter. [#11744](https://github.com/ClickHouse/ClickHouse/pull/11744) ([alesapin](https://github.com/alesapin)).
+* Fixed LOGICAL_ERROR caused by wrong type deduction of complex literals in Values input format. [#11732](https://github.com/ClickHouse/ClickHouse/pull/11732) ([tavplubix](https://github.com/tavplubix)).
+* Fix `ORDER BY ... WITH FILL` over const columns. [#11697](https://github.com/ClickHouse/ClickHouse/pull/11697) ([Anton Popov](https://github.com/CurtizJ)).
+* Pass proper timeouts when communicating with XDBC bridge. Recently timeouts were not respected when checking bridge liveness and receiving meta info. [#11690](https://github.com/ClickHouse/ClickHouse/pull/11690) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix error which leads to an incorrect state of `system.mutations`. It may show that whole mutation is already done but the server still has `MUTATE_PART` tasks in the replication queue and tries to execute them. This fixes [#11611](https://github.com/ClickHouse/ClickHouse/issues/11611). [#11681](https://github.com/ClickHouse/ClickHouse/pull/11681) ([alesapin](https://github.com/alesapin)).
+* Add support for regular expressions with case-insensitive flags. This fixes [#11101](https://github.com/ClickHouse/ClickHouse/issues/11101) and fixes [#11506](https://github.com/ClickHouse/ClickHouse/issues/11506). [#11649](https://github.com/ClickHouse/ClickHouse/pull/11649) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove trivial count query optimization if row-level security is set. In previous versions the user get total count of records in a table instead filtered. This fixes [#11352](https://github.com/ClickHouse/ClickHouse/issues/11352). [#11644](https://github.com/ClickHouse/ClickHouse/pull/11644) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bloom filters for String (data skipping indices). [#11638](https://github.com/ClickHouse/ClickHouse/pull/11638) ([Azat Khuzhin](https://github.com/azat)).
+* Fix rare crash caused by using `Nullable` column in prewhere condition. (Probably it is connected with [#11572](https://github.com/ClickHouse/ClickHouse/issues/11572) somehow). [#11608](https://github.com/ClickHouse/ClickHouse/pull/11608) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix error `Block structure mismatch` for queries with sampling reading from `Buffer` table. [#11602](https://github.com/ClickHouse/ClickHouse/pull/11602) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix wrong exit code of the clickhouse-client, when exception.code() % 256 = 0. [#11601](https://github.com/ClickHouse/ClickHouse/pull/11601) ([filimonov](https://github.com/filimonov)).
+* Fix trivial error in log message about "Mark cache size was lowered" at server startup. This closes [#11399](https://github.com/ClickHouse/ClickHouse/issues/11399). [#11589](https://github.com/ClickHouse/ClickHouse/pull/11589) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix error `Size of offsets does not match size of column` for queries with `PREWHERE column in (subquery)` and `ARRAY JOIN`. [#11580](https://github.com/ClickHouse/ClickHouse/pull/11580) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* All queries in HTTP session have had the same query_id. It is fixed. [#11578](https://github.com/ClickHouse/ClickHouse/pull/11578) ([tavplubix](https://github.com/tavplubix)).
+* Now clickhouse-server docker container will prefer IPv6 checking server aliveness. [#11550](https://github.com/ClickHouse/ClickHouse/pull/11550) ([Ivan Starkov](https://github.com/istarkov)).
+* Fix shard_num/replica_num for `<node>` (breaks use_compact_format_in_distributed_parts_names). [#11528](https://github.com/ClickHouse/ClickHouse/pull/11528) ([Azat Khuzhin](https://github.com/azat)).
+* Fix memory leak when exception is thrown in the middle of aggregation with -State functions. This fixes [#8995](https://github.com/ClickHouse/ClickHouse/issues/8995). [#11496](https://github.com/ClickHouse/ClickHouse/pull/11496) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix wrong results of distributed queries when alias could override qualified column name. Fixes [#9672](https://github.com/ClickHouse/ClickHouse/issues/9672) [#9714](https://github.com/ClickHouse/ClickHouse/issues/9714). [#9972](https://github.com/ClickHouse/ClickHouse/pull/9972) ([Artem Zuikov](https://github.com/4ertus2)).
+
+
+### ClickHouse release v20.3.11.97-lts 2020-06-10
+
+#### New Feature
+
+* Now ClickHouse controls timeouts of dictionary sources on its side. Two new settings added to cache dictionary configuration: `strict_max_lifetime_seconds`, which is `max_lifetime` by default and `query_wait_timeout_milliseconds`, which is one minute by default. The first settings is also useful with `allow_read_expired_keys` settings (to forbid reading very expired keys). [#10337](https://github.com/ClickHouse/ClickHouse/pull/10337) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+
+#### Bug Fix
+
+* Fix the error `Data compressed with different methods` that can happen if `min_bytes_to_use_direct_io` is enabled and PREWHERE is active and using SAMPLE or high number of threads. This fixes [#11539](https://github.com/ClickHouse/ClickHouse/issues/11539). [#11540](https://github.com/ClickHouse/ClickHouse/pull/11540) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix return compressed size for codecs. [#11448](https://github.com/ClickHouse/ClickHouse/pull/11448) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix server crash when a column has compression codec with non-literal arguments. Fixes [#11365](https://github.com/ClickHouse/ClickHouse/issues/11365). [#11431](https://github.com/ClickHouse/ClickHouse/pull/11431) ([alesapin](https://github.com/alesapin)).
+* Fix pointInPolygon with nan as point. Fixes [#11375](https://github.com/ClickHouse/ClickHouse/issues/11375). [#11421](https://github.com/ClickHouse/ClickHouse/pull/11421) ([Alexey Ilyukhov](https://github.com/livace)).
+* Fix crash in JOIN over LowCarinality(T) and Nullable(T). [#11380](https://github.com/ClickHouse/ClickHouse/issues/11380). [#11414](https://github.com/ClickHouse/ClickHouse/pull/11414) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix error code for wrong `USING` key. [#11373](https://github.com/ClickHouse/ClickHouse/issues/11373). [#11404](https://github.com/ClickHouse/ClickHouse/pull/11404) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fixed geohashesInBox with arguments outside of latitude/longitude range. [#11403](https://github.com/ClickHouse/ClickHouse/pull/11403) ([Vasily Nemkov](https://github.com/Enmk)).
+* Better errors for `joinGet()` functions. [#11389](https://github.com/ClickHouse/ClickHouse/pull/11389) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix possible `Pipeline stuck` error for queries with external sort and limit. Fixes [#11359](https://github.com/ClickHouse/ClickHouse/issues/11359). [#11366](https://github.com/ClickHouse/ClickHouse/pull/11366) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Remove redundant lock during parts send in ReplicatedMergeTree. [#11354](https://github.com/ClickHouse/ClickHouse/pull/11354) ([alesapin](https://github.com/alesapin)).
+* Fix support for `\G` (vertical output) in clickhouse-client in multiline mode. This closes [#9933](https://github.com/ClickHouse/ClickHouse/issues/9933). [#11350](https://github.com/ClickHouse/ClickHouse/pull/11350) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash in direct selects from StorageJoin (without JOIN) and wrong nullability. [#11340](https://github.com/ClickHouse/ClickHouse/pull/11340) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix crash in `quantilesExactWeightedArray`. [#11337](https://github.com/ClickHouse/ClickHouse/pull/11337) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Now merges stopped before change metadata in `ALTER` queries. [#11335](https://github.com/ClickHouse/ClickHouse/pull/11335) ([alesapin](https://github.com/alesapin)).
+* Make writing to `MATERIALIZED VIEW` with setting `parallel_view_processing = 1` parallel again. Fixes [#10241](https://github.com/ClickHouse/ClickHouse/issues/10241). [#11330](https://github.com/ClickHouse/ClickHouse/pull/11330) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix visitParamExtractRaw when extracted JSON has strings with unbalanced { or [. [#11318](https://github.com/ClickHouse/ClickHouse/pull/11318) ([Ewout](https://github.com/devwout)).
+* Fix very rare race condition in ThreadPool. [#11314](https://github.com/ClickHouse/ClickHouse/pull/11314) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix potential uninitialized memory in conversion. Example: `SELECT toIntervalSecond(now64())`. [#11311](https://github.com/ClickHouse/ClickHouse/pull/11311) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix the issue when index analysis cannot work if a table has Array column in primary key and if a query is filtering by this column with `empty` or `notEmpty` functions. This fixes [#11286](https://github.com/ClickHouse/ClickHouse/issues/11286). [#11303](https://github.com/ClickHouse/ClickHouse/pull/11303) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bug when query speed estimation can be incorrect and the limit of `min_execution_speed` may not work or work incorrectly if the query is throttled by `max_network_bandwidth`, `max_execution_speed` or `priority` settings. Change the default value of `timeout_before_checking_execution_speed` to non-zero, because otherwise the settings `min_execution_speed` and `max_execution_speed` have no effect. This fixes [#11297](https://github.com/ClickHouse/ClickHouse/issues/11297). This fixes [#5732](https://github.com/ClickHouse/ClickHouse/issues/5732). This fixes [#6228](https://github.com/ClickHouse/ClickHouse/issues/6228). Usability improvement: avoid concatenation of exception message with progress bar in `clickhouse-client`. [#11296](https://github.com/ClickHouse/ClickHouse/pull/11296) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash while reading malformed data in Protobuf format. This fixes [#5957](https://github.com/ClickHouse/ClickHouse/issues/5957), fixes [#11203](https://github.com/ClickHouse/ClickHouse/issues/11203). [#11258](https://github.com/ClickHouse/ClickHouse/pull/11258) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed a bug when cache-dictionary could return default value instead of normal (when there are only expired keys). This affects only string fields. [#11233](https://github.com/ClickHouse/ClickHouse/pull/11233) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix error `Block structure mismatch in QueryPipeline` while reading from `VIEW` with constants in inner query. Fixes [#11181](https://github.com/ClickHouse/ClickHouse/issues/11181). [#11205](https://github.com/ClickHouse/ClickHouse/pull/11205) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix possible exception `Invalid status for associated output`. [#11200](https://github.com/ClickHouse/ClickHouse/pull/11200) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix possible error `Cannot capture column` for higher-order functions with `Array(Array(LowCardinality))` captured argument. [#11185](https://github.com/ClickHouse/ClickHouse/pull/11185) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed S3 globbing which could fail in case of more than 1000 keys and some backends. [#11179](https://github.com/ClickHouse/ClickHouse/pull/11179) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* If data skipping index is dependent on columns that are going to be modified during background merge (for SummingMergeTree, AggregatingMergeTree as well as for TTL GROUP BY), it was calculated incorrectly. This issue is fixed by moving index calculation after merge so the index is calculated on merged data. [#11162](https://github.com/ClickHouse/ClickHouse/pull/11162) ([Azat Khuzhin](https://github.com/azat)).
+* Fix excessive reserving of threads for simple queries (optimization for reducing the number of threads, which was partly broken after changes in pipeline). [#11114](https://github.com/ClickHouse/ClickHouse/pull/11114) ([Azat Khuzhin](https://github.com/azat)).
+* Fix predicates optimization for distributed queries (`enable_optimize_predicate_expression=1`) for queries with `HAVING` section (i.e. when filtering on the server initiator is required), by preserving the order of expressions (and this is enough to fix), and also force aggregator use column names over indexes. Fixes: [#10613](https://github.com/ClickHouse/ClickHouse/issues/10613), [#11413](https://github.com/ClickHouse/ClickHouse/issues/11413). [#10621](https://github.com/ClickHouse/ClickHouse/pull/10621) ([Azat Khuzhin](https://github.com/azat)).
+* Introduce commit retry logic to decrease the possibility of getting duplicates from Kafka in rare cases when offset commit was failed. [#9884](https://github.com/ClickHouse/ClickHouse/pull/9884) ([filimonov](https://github.com/filimonov)).
+
+#### Performance Improvement
+
+* Get dictionary and check access rights only once per each call of any function reading external dictionaries. [#10928](https://github.com/ClickHouse/ClickHouse/pull/10928) ([Vitaly Baranov](https://github.com/vitlibar)).
+
+#### Build/Testing/Packaging Improvement
+
+* Fix several flaky integration tests. [#11355](https://github.com/ClickHouse/ClickHouse/pull/11355) ([alesapin](https://github.com/alesapin)).
+
+### ClickHouse release v20.3.10.75-lts 2020-05-23
+
+#### Bug Fix
+
+* Removed logging from mutation finalization task if nothing was finalized. [#11109](https://github.com/ClickHouse/ClickHouse/pull/11109) ([alesapin](https://github.com/alesapin)).
+* Fixed `parseDateTime64BestEffort` argument resolution bugs. [#11038](https://github.com/ClickHouse/ClickHouse/pull/11038) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fixed incorrect raw data size in method `getRawData()`. [#10964](https://github.com/ClickHouse/ClickHouse/pull/10964) ([Igr](https://github.com/ObjatieGroba)).
+* Fixed incompatibility of two-level aggregation between versions 20.1 and earlier. This incompatibility happens when different versions of ClickHouse are used on initiator node and remote nodes and the size of `GROUP BY` result is large and aggregation is performed by a single `String` field. It leads to several unmerged rows for a single key in result. [#10952](https://github.com/ClickHouse/ClickHouse/pull/10952) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed backward compatibility with tuples in `Distributed` tables. [#10889](https://github.com/ClickHouse/ClickHouse/pull/10889) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed `SIGSEGV` in `StringHashTable` if such a key does not exist. [#10870](https://github.com/ClickHouse/ClickHouse/pull/10870) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed bug in `ReplicatedMergeTree` which might cause some `ALTER` on `OPTIMIZE` query to hang waiting for some replica after it become inactive. [#10849](https://github.com/ClickHouse/ClickHouse/pull/10849) ([tavplubix](https://github.com/tavplubix)).
+* Fixed columns order after `Block::sortColumns()`. [#10826](https://github.com/ClickHouse/ClickHouse/pull/10826) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed the issue with `ODBC` bridge when no quoting of identifiers is requested. Fixes [#7984](https://github.com/ClickHouse/ClickHouse/issues/7984). [#10821](https://github.com/ClickHouse/ClickHouse/pull/10821) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `UBSan` and `MSan` report in `DateLUT`. [#10798](https://github.com/ClickHouse/ClickHouse/pull/10798) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed incorrect type conversion in key conditions. Fixes [#6287](https://github.com/ClickHouse/ClickHouse/issues/6287). [#10791](https://github.com/ClickHouse/ClickHouse/pull/10791) ([Andrew Onyshchuk](https://github.com/oandrew))
+* Fixed `parallel_view_processing` behavior. Now all insertions into `MATERIALIZED VIEW` without exception should be finished if exception happened. Fixes [#10241](https://github.com/ClickHouse/ClickHouse/issues/10241). [#10757](https://github.com/ClickHouse/ClickHouse/pull/10757) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed combinator -`OrNull` and `-OrDefault` when combined with `-State`. [#10741](https://github.com/ClickHouse/ClickHouse/pull/10741) ([hcz](https://github.com/hczhcz)).
+* Fixed crash in `generateRandom` with nested types. Fixes [#10583](https://github.com/ClickHouse/ClickHouse/issues/10583). [#10734](https://github.com/ClickHouse/ClickHouse/pull/10734) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed data corruption for `LowCardinality(FixedString)` key column in `SummingMergeTree` which could have happened after merge. Fixes [#10489](https://github.com/ClickHouse/ClickHouse/issues/10489). [#10721](https://github.com/ClickHouse/ClickHouse/pull/10721) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed possible buffer overflow in function `h3EdgeAngle`. [#10711](https://github.com/ClickHouse/ClickHouse/pull/10711) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed disappearing totals. Totals could have being filtered if query had had join or subquery with external where condition. Fixes [#10674](https://github.com/ClickHouse/ClickHouse/issues/10674). [#10698](https://github.com/ClickHouse/ClickHouse/pull/10698) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed multiple usages of `IN` operator with the identical set in one query. [#10686](https://github.com/ClickHouse/ClickHouse/pull/10686) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed bug, which causes http requests stuck on client close when `readonly=2` and `cancel_http_readonly_queries_on_client_close=1`. Fixes [#7939](https://github.com/ClickHouse/ClickHouse/issues/7939), [#7019](https://github.com/ClickHouse/ClickHouse/issues/7019), [#7736](https://github.com/ClickHouse/ClickHouse/issues/7736), [#7091](https://github.com/ClickHouse/ClickHouse/issues/7091). [#10684](https://github.com/ClickHouse/ClickHouse/pull/10684) ([tavplubix](https://github.com/tavplubix)).
+* Fixed order of parameters in `AggregateTransform` constructor. [#10667](https://github.com/ClickHouse/ClickHouse/pull/10667) ([palasonic1](https://github.com/palasonic1)).
+* Fixed the lack of parallel execution of remote queries with `distributed_aggregation_memory_efficient` enabled. Fixes [#10655](https://github.com/ClickHouse/ClickHouse/issues/10655). [#10664](https://github.com/ClickHouse/ClickHouse/pull/10664) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed possible incorrect number of rows for queries with `LIMIT`. Fixes [#10566](https://github.com/ClickHouse/ClickHouse/issues/10566), [#10709](https://github.com/ClickHouse/ClickHouse/issues/10709). [#10660](https://github.com/ClickHouse/ClickHouse/pull/10660) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed a bug which locks concurrent alters when table has a lot of parts. [#10659](https://github.com/ClickHouse/ClickHouse/pull/10659) ([alesapin](https://github.com/alesapin)).
+* Fixed a bug when on `SYSTEM DROP DNS CACHE` query also drop caches, which are used to check if user is allowed to connect from some IP addresses. [#10608](https://github.com/ClickHouse/ClickHouse/pull/10608) ([tavplubix](https://github.com/tavplubix)).
+* Fixed incorrect scalar results inside inner query of `MATERIALIZED VIEW` in case if this query contained dependent table. [#10603](https://github.com/ClickHouse/ClickHouse/pull/10603) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed `SELECT` of column `ALIAS` which default expression type different from column type. [#10563](https://github.com/ClickHouse/ClickHouse/pull/10563) ([Azat Khuzhin](https://github.com/azat)).
+* Implemented comparison between DateTime64 and String values. [#10560](https://github.com/ClickHouse/ClickHouse/pull/10560) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fixed index corruption, which may occur in some cases after merge compact parts into another compact part. [#10531](https://github.com/ClickHouse/ClickHouse/pull/10531) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed the situation, when mutation finished all parts, but hung up in `is_done=0`. [#10526](https://github.com/ClickHouse/ClickHouse/pull/10526) ([alesapin](https://github.com/alesapin)).
+* Fixed overflow at beginning of unix epoch for timezones with fractional offset from `UTC`. This fixes [#9335](https://github.com/ClickHouse/ClickHouse/issues/9335). [#10513](https://github.com/ClickHouse/ClickHouse/pull/10513) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed improper shutdown of `Distributed` storage. [#10491](https://github.com/ClickHouse/ClickHouse/pull/10491) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed numeric overflow in `simpleLinearRegression` over large integers. [#10474](https://github.com/ClickHouse/ClickHouse/pull/10474) ([hcz](https://github.com/hczhcz)).
+
+
+#### Build/Testing/Packaging Improvement
+
+* Fix UBSan report in LZ4 library. [#10631](https://github.com/ClickHouse/ClickHouse/pull/10631) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix clang-10 build. [#10238](https://github.com/ClickHouse/ClickHouse/issues/10238). [#10370](https://github.com/ClickHouse/ClickHouse/pull/10370) ([Amos Bird](https://github.com/amosbird)).
+* Added failing tests about `max_rows_to_sort` setting. [#10268](https://github.com/ClickHouse/ClickHouse/pull/10268) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added some improvements in printing diagnostic info in input formats. Fixes [#10204](https://github.com/ClickHouse/ClickHouse/issues/10204). [#10418](https://github.com/ClickHouse/ClickHouse/pull/10418) ([tavplubix](https://github.com/tavplubix)).
+* Added CA certificates to clickhouse-server docker image. [#10476](https://github.com/ClickHouse/ClickHouse/pull/10476) ([filimonov](https://github.com/filimonov)).
+
+#### Bug fix
+
+* Fix error `the BloomFilter false positive must be a double number between 0 and 1` [#10551](https://github.com/ClickHouse/ClickHouse/issues/10551). [#10569](https://github.com/ClickHouse/ClickHouse/pull/10569) ([Winter Zhang](https://github.com/zhang2014)).
+
+
+### ClickHouse release v20.3.8.53, 2020-04-23
+
+#### Bug Fix
+* Fixed wrong behaviour of datetime functions for timezones that has altered between positive and negative offsets from UTC (e.g. Pacific/Kiritimati). This fixes [#7202](https://github.com/ClickHouse/ClickHouse/issues/7202) [#10369](https://github.com/ClickHouse/ClickHouse/pull/10369) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix possible segfault with `distributed_group_by_no_merge` enabled (introduced in 20.3.7.46 by [#10131](https://github.com/ClickHouse/ClickHouse/issues/10131)). [#10399](https://github.com/ClickHouse/ClickHouse/pull/10399) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix wrong flattening of `Array(Tuple(...))` data types. This fixes [#10259](https://github.com/ClickHouse/ClickHouse/issues/10259) [#10390](https://github.com/ClickHouse/ClickHouse/pull/10390) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Drop disks reservation in Aggregator. This fixes bug in disk space reservation, which may cause big external aggregation to fail even if it could be completed successfully [#10375](https://github.com/ClickHouse/ClickHouse/pull/10375) ([Azat Khuzhin](https://github.com/azat))
+* Fixed `DROP` vs `OPTIMIZE` race in `ReplicatedMergeTree`. `DROP` could left some garbage in replica path in ZooKeeper if there was concurrent `OPTIMIZE` query. [#10312](https://github.com/ClickHouse/ClickHouse/pull/10312) ([tavplubix](https://github.com/tavplubix))
+* Fix bug when server cannot attach table after column default was altered. [#10441](https://github.com/ClickHouse/ClickHouse/pull/10441) ([alesapin](https://github.com/alesapin))
+* Do not remove metadata directory when attach database fails before loading tables.  [#10442](https://github.com/ClickHouse/ClickHouse/pull/10442) ([Winter Zhang](https://github.com/zhang2014))
+* Fixed several bugs when some data was inserted with quorum, then deleted somehow (DROP PARTITION, TTL) and this leaded to the stuck of INSERTs or false-positive exceptions in SELECTs. This fixes [#9946](https://github.com/ClickHouse/ClickHouse/issues/9946) [#10188](https://github.com/ClickHouse/ClickHouse/pull/10188) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Fix possible `Pipeline stuck` error in `ConcatProcessor` which could have happened in remote query. [#10381](https://github.com/ClickHouse/ClickHouse/pull/10381) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fixed wrong behavior in HashTable that caused compilation error when trying to read HashMap from buffer. [#10386](https://github.com/ClickHouse/ClickHouse/pull/10386) ([palasonic1](https://github.com/palasonic1))
+* Allow to use `count(*)` with multiple JOINs. Fixes [#9853](https://github.com/ClickHouse/ClickHouse/issues/9853) [#10291](https://github.com/ClickHouse/ClickHouse/pull/10291) ([Artem Zuikov](https://github.com/4ertus2))
+* Prefer `fallback_to_stale_replicas` over `skip_unavailable_shards`, otherwise when both settings specified and there are no up-to-date replicas the query will fail (patch from @alex-zaitsev). Fixes: [#2564](https://github.com/ClickHouse/ClickHouse/issues/2564). [#10422](https://github.com/ClickHouse/ClickHouse/pull/10422) ([Azat Khuzhin](https://github.com/azat))
+* Fix the issue when a query with ARRAY JOIN, ORDER BY and LIMIT may return incomplete result. This fixes [#10226](https://github.com/ClickHouse/ClickHouse/issues/10226). Author: [Vadim Plakhtinskiy](https://github.com/VadimPlh). [#10427](https://github.com/ClickHouse/ClickHouse/pull/10427) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Check the number and type of arguments when creating BloomFilter index [#9623](https://github.com/ClickHouse/ClickHouse/issues/9623) [#10431](https://github.com/ClickHouse/ClickHouse/pull/10431) ([Winter Zhang](https://github.com/zhang2014))
+
+#### Performance Improvement
+* Improved performance of queries with explicitly defined sets at right side of `IN` operator and tuples in the left side. This fixes performance regression in version 20.3. [#9740](https://github.com/ClickHouse/ClickHouse/pull/9740), [#10385](https://github.com/ClickHouse/ClickHouse/pull/10385) ([Anton Popov](https://github.com/CurtizJ))
+
+### ClickHouse release v20.3.7.46, 2020-04-17
+
+#### Bug Fix
+
+* Fix `Logical error: CROSS JOIN has expressions` error for queries with comma and names joins mix. [#10311](https://github.com/ClickHouse/ClickHouse/pull/10311) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix queries with `max_bytes_before_external_group_by`. [#10302](https://github.com/ClickHouse/ClickHouse/pull/10302) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix move-to-prewhere optimization in presense of arrayJoin functions (in certain cases). This fixes [#10092](https://github.com/ClickHouse/ClickHouse/issues/10092). [#10195](https://github.com/ClickHouse/ClickHouse/pull/10195) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add the ability to relax the restriction on non-deterministic functions usage in mutations with `allow_nondeterministic_mutations` setting. [#10186](https://github.com/ClickHouse/ClickHouse/pull/10186) ([filimonov](https://github.com/filimonov)).
+
+### ClickHouse release v20.3.6.40, 2020-04-16
+
+#### New Feature
+
+* Added function `isConstant`. This function checks whether its argument is constant expression and returns 1 or 0. It is intended for development, debugging and demonstration purposes. [#10198](https://github.com/ClickHouse/ClickHouse/pull/10198) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### Bug Fix
+
+* Fix error `Pipeline stuck` with `max_rows_to_group_by` and `group_by_overflow_mode = 'break'`. [#10279](https://github.com/ClickHouse/ClickHouse/pull/10279) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix rare possible exception `Cannot drain connections: cancel first`. [#10239](https://github.com/ClickHouse/ClickHouse/pull/10239) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed bug where ClickHouse would throw "Unknown function lambda." error message when user tries to run ALTER UPDATE/DELETE on tables with ENGINE = Replicated*. Check for nondeterministic functions now handles lambda expressions correctly. [#10237](https://github.com/ClickHouse/ClickHouse/pull/10237) ([Alexander Kazakov](https://github.com/Akazz)).
+* Fixed "generateRandom" function for Date type. This fixes [#9973](https://github.com/ClickHouse/ClickHouse/issues/9973). Fix an edge case when dates with year 2106 are inserted to MergeTree tables with old-style partitioning but partitions are named with year 1970. [#10218](https://github.com/ClickHouse/ClickHouse/pull/10218) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Convert types if the table definition of a View does not correspond to the SELECT query. This fixes [#10180](https://github.com/ClickHouse/ClickHouse/issues/10180) and [#10022](https://github.com/ClickHouse/ClickHouse/issues/10022). [#10217](https://github.com/ClickHouse/ClickHouse/pull/10217) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `parseDateTimeBestEffort` for strings in RFC-2822 when day of week is Tuesday or Thursday. This fixes [#10082](https://github.com/ClickHouse/ClickHouse/issues/10082). [#10214](https://github.com/ClickHouse/ClickHouse/pull/10214) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix column names of constants inside JOIN that may clash with names of constants outside of JOIN. [#10207](https://github.com/ClickHouse/ClickHouse/pull/10207) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible inifinite query execution when the query actually should stop on LIMIT, while reading from infinite source like `system.numbers` or `system.zeros`. [#10206](https://github.com/ClickHouse/ClickHouse/pull/10206) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix using the current database for access checking when the database isn't specified. [#10192](https://github.com/ClickHouse/ClickHouse/pull/10192) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Convert blocks if structure does not match on INSERT into Distributed(). [#10135](https://github.com/ClickHouse/ClickHouse/pull/10135) ([Azat Khuzhin](https://github.com/azat)).
+* Fix possible incorrect result for extremes in processors pipeline. [#10131](https://github.com/ClickHouse/ClickHouse/pull/10131) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix some kinds of alters with compact parts. [#10130](https://github.com/ClickHouse/ClickHouse/pull/10130) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix incorrect `index_granularity_bytes` check while creating new replica. Fixes [#10098](https://github.com/ClickHouse/ClickHouse/issues/10098). [#10121](https://github.com/ClickHouse/ClickHouse/pull/10121) ([alesapin](https://github.com/alesapin)).
+* Fix SIGSEGV on INSERT into Distributed table when its structure differs from the underlying tables. [#10105](https://github.com/ClickHouse/ClickHouse/pull/10105) ([Azat Khuzhin](https://github.com/azat)).
+* Fix possible rows loss for queries with `JOIN` and `UNION ALL`. Fixes [#9826](https://github.com/ClickHouse/ClickHouse/issues/9826), [#10113](https://github.com/ClickHouse/ClickHouse/issues/10113). [#10099](https://github.com/ClickHouse/ClickHouse/pull/10099) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed replicated tables startup when updating from an old ClickHouse version where `/table/replicas/replica_name/metadata` node does not exist. Fixes [#10037](https://github.com/ClickHouse/ClickHouse/issues/10037). [#10095](https://github.com/ClickHouse/ClickHouse/pull/10095) ([alesapin](https://github.com/alesapin)).
+* Add some arguments check and support identifier arguments for MySQL Database Engine. [#10077](https://github.com/ClickHouse/ClickHouse/pull/10077) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix bug in clickhouse dictionary source from localhost clickhouse server. The bug may lead to memory corruption if types in dictionary and source are not compatible. [#10071](https://github.com/ClickHouse/ClickHouse/pull/10071) ([alesapin](https://github.com/alesapin)).
+* Fix bug in `CHECK TABLE` query when table contain skip indices. [#10068](https://github.com/ClickHouse/ClickHouse/pull/10068) ([alesapin](https://github.com/alesapin)).
+* Fix error `Cannot clone block with columns because block has 0 columns ... While executing GroupingAggregatedTransform`. It happened when setting `distributed_aggregation_memory_efficient` was enabled, and distributed query read aggregating data with different level from different shards (mixed single and two level aggregation). [#10063](https://github.com/ClickHouse/ClickHouse/pull/10063) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix a segmentation fault that could occur in GROUP BY over string keys containing trailing zero bytes ([#8636](https://github.com/ClickHouse/ClickHouse/issues/8636), [#8925](https://github.com/ClickHouse/ClickHouse/issues/8925)). [#10025](https://github.com/ClickHouse/ClickHouse/pull/10025) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fix the number of threads used for remote query execution (performance regression, since 20.3). This happened when query from `Distributed` table was executed simultaneously on local and remote shards. Fixes [#9965](https://github.com/ClickHouse/ClickHouse/issues/9965). [#9971](https://github.com/ClickHouse/ClickHouse/pull/9971) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug in which the necessary tables weren't retrieved at one of the processing stages of queries to some databases. Fixes [#9699](https://github.com/ClickHouse/ClickHouse/issues/9699). [#9949](https://github.com/ClickHouse/ClickHouse/pull/9949) ([achulkov2](https://github.com/achulkov2)).
+* Fix 'Not found column in block' error when `JOIN` appears with `TOTALS`. Fixes [#9839](https://github.com/ClickHouse/ClickHouse/issues/9839). [#9939](https://github.com/ClickHouse/ClickHouse/pull/9939) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix a bug with `ON CLUSTER` DDL queries freezing on server startup. [#9927](https://github.com/ClickHouse/ClickHouse/pull/9927) ([Gagan Arneja](https://github.com/garneja)).
+* Fix parsing multiple hosts set in the CREATE USER command, e.g. `CREATE USER user6 HOST NAME REGEXP 'lo.?*host', NAME REGEXP 'lo*host'`. [#9924](https://github.com/ClickHouse/ClickHouse/pull/9924) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix `TRUNCATE` for Join table engine ([#9917](https://github.com/ClickHouse/ClickHouse/issues/9917)). [#9920](https://github.com/ClickHouse/ClickHouse/pull/9920) ([Amos Bird](https://github.com/amosbird)).
+* Fix "scalar does not exist" error in ALTERs ([#9878](https://github.com/ClickHouse/ClickHouse/issues/9878)). [#9904](https://github.com/ClickHouse/ClickHouse/pull/9904) ([Amos Bird](https://github.com/amosbird)).
+* Fix race condition between drop and optimize in `ReplicatedMergeTree`. [#9901](https://github.com/ClickHouse/ClickHouse/pull/9901) ([alesapin](https://github.com/alesapin)).
+* Fix error with qualified names in `distributed_product_mode='local'`. Fixes [#4756](https://github.com/ClickHouse/ClickHouse/issues/4756). [#9891](https://github.com/ClickHouse/ClickHouse/pull/9891) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix calculating grants for introspection functions from the setting 'allow_introspection_functions'. [#9840](https://github.com/ClickHouse/ClickHouse/pull/9840) ([Vitaly Baranov](https://github.com/vitlibar)).
+
+#### Build/Testing/Packaging Improvement
+
+* Fix integration test `test_settings_constraints`. [#9962](https://github.com/ClickHouse/ClickHouse/pull/9962) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Removed dependency on `clock_getres`. [#9833](https://github.com/ClickHouse/ClickHouse/pull/9833) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+
+### ClickHouse release v20.3.5.21, 2020-03-27
+
+#### Bug Fix
+
+* Fix 'Different expressions with the same alias' error when query has PREWHERE and WHERE on distributed table and `SET distributed_product_mode = 'local'`. [#9871](https://github.com/ClickHouse/ClickHouse/pull/9871) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix mutations excessive memory consumption for tables with a composite primary key. This fixes [#9850](https://github.com/ClickHouse/ClickHouse/issues/9850). [#9860](https://github.com/ClickHouse/ClickHouse/pull/9860) ([alesapin](https://github.com/alesapin)).
+* For INSERT queries shard now clamps the settings got from the initiator to the shard's constaints instead of throwing an exception. This fix allows to send INSERT queries to a shard with another constraints. This change improves fix [#9447](https://github.com/ClickHouse/ClickHouse/issues/9447). [#9852](https://github.com/ClickHouse/ClickHouse/pull/9852) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix 'COMMA to CROSS JOIN rewriter is not enabled or cannot rewrite query' error in case of subqueries with COMMA JOIN out of tables lists (i.e. in WHERE). Fixes [#9782](https://github.com/ClickHouse/ClickHouse/issues/9782). [#9830](https://github.com/ClickHouse/ClickHouse/pull/9830) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix possible exception `Got 0 in totals chunk, expected 1` on client. It happened for queries with `JOIN` in case if right joined table had zero rows. Example: `select * from system.one t1 join system.one t2 on t1.dummy = t2.dummy limit 0 FORMAT TabSeparated;`. Fixes [#9777](https://github.com/ClickHouse/ClickHouse/issues/9777). [#9823](https://github.com/ClickHouse/ClickHouse/pull/9823) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix SIGSEGV with optimize_skip_unused_shards when type cannot be converted. [#9804](https://github.com/ClickHouse/ClickHouse/pull/9804) ([Azat Khuzhin](https://github.com/azat)).
+* Fix broken `ALTER TABLE DELETE COLUMN` query for compact parts. [#9779](https://github.com/ClickHouse/ClickHouse/pull/9779) ([alesapin](https://github.com/alesapin)).
+* Fix max_distributed_connections (w/ and w/o Processors). [#9673](https://github.com/ClickHouse/ClickHouse/pull/9673) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed a few cases when timezone of the function argument wasn't used properly. [#9574](https://github.com/ClickHouse/ClickHouse/pull/9574) ([Vasily Nemkov](https://github.com/Enmk)).
+
+#### Improvement
+
+* Remove order by stage from mutations because we read from a single ordered part in a single thread. Also add check that the order of rows in mutation is ordered in sorting key order and this order is not violated. [#9886](https://github.com/ClickHouse/ClickHouse/pull/9886) ([alesapin](https://github.com/alesapin)).
+
+
+### ClickHouse release v20.3.4.10, 2020-03-20
+
+#### Bug Fix
+* This release also contains all bug fixes from 20.1.8.41
+* Fix missing `rows_before_limit_at_least` for queries over http (with processors pipeline). This fixes [#9730](https://github.com/ClickHouse/ClickHouse/issues/9730). [#9757](https://github.com/ClickHouse/ClickHouse/pull/9757) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+
+
+### ClickHouse release v20.3.3.6, 2020-03-17
+
+#### Bug Fix
+* This release also contains all bug fixes from 20.1.7.38
+* Fix bug in a replication that does not allow replication to work if the user has executed mutations on the previous version. This fixes [#9645](https://github.com/ClickHouse/ClickHouse/issues/9645). [#9652](https://github.com/ClickHouse/ClickHouse/pull/9652) ([alesapin](https://github.com/alesapin)). It makes version 20.3 backward compatible again.
+* Add setting `use_compact_format_in_distributed_parts_names` which allows to write files for `INSERT` queries into `Distributed` table with more compact format. This fixes [#9647](https://github.com/ClickHouse/ClickHouse/issues/9647). [#9653](https://github.com/ClickHouse/ClickHouse/pull/9653) ([alesapin](https://github.com/alesapin)). It makes version 20.3 backward compatible again.
+
+### ClickHouse release v20.3.2.1, 2020-03-12
+
+#### Backward Incompatible Change
+
+* Fixed the issue `file name too long` when sending data for `Distributed` tables for a large number of replicas. Fixed the issue that replica credentials were exposed in the server log. The format of directory name on disk was changed to `[shard{shard_index}[_replica{replica_index}]]`. [#8911](https://github.com/ClickHouse/ClickHouse/pull/8911) ([Mikhail Korotov](https://github.com/millb)) After you upgrade to the new version, you will not be able to downgrade without manual intervention, because old server version does not recognize the new directory format. If you want to downgrade, you have to manually rename the corresponding directories to the old format. This change is relevant only if you have used asynchronous `INSERT`s to `Distributed` tables. In the version 20.3.3 we will introduce a setting that will allow you to enable the new format gradually.
+* Changed the format of replication log entries for mutation commands. You have to wait for old mutations to process before installing the new version.
+* Implement simple memory profiler that dumps stacktraces to `system.trace_log` every N bytes over soft allocation limit [#8765](https://github.com/ClickHouse/ClickHouse/pull/8765) ([Ivan](https://github.com/abyss7)) [#9472](https://github.com/ClickHouse/ClickHouse/pull/9472) ([alexey-milovidov](https://github.com/alexey-milovidov)) The column of `system.trace_log` was renamed from `timer_type` to `trace_type`. This will require changes in third-party performance analysis and flamegraph processing tools.
+* Use OS thread id everywhere instead of internal thread number. This fixes [#7477](https://github.com/ClickHouse/ClickHouse/issues/7477) Old `clickhouse-client` cannot receive logs that are send from the server when the setting `send_logs_level` is enabled, because the names and types of the structured log messages were changed. On the other hand, different server versions can send logs with different types to each other. When you don't use the `send_logs_level` setting, you should not care. [#8954](https://github.com/ClickHouse/ClickHouse/pull/8954) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Remove `indexHint` function [#9542](https://github.com/ClickHouse/ClickHouse/pull/9542) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Remove `findClusterIndex`, `findClusterValue` functions. This fixes [#8641](https://github.com/ClickHouse/ClickHouse/issues/8641). If you were using these functions, send an email to `clickhouse-feedback@yandex-team.com` [#9543](https://github.com/ClickHouse/ClickHouse/pull/9543) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Now it's not allowed to create columns or add columns with `SELECT` subquery as default expression. [#9481](https://github.com/ClickHouse/ClickHouse/pull/9481) ([alesapin](https://github.com/alesapin))
+* Require aliases for subqueries in JOIN. [#9274](https://github.com/ClickHouse/ClickHouse/pull/9274) ([Artem Zuikov](https://github.com/4ertus2))
+* Improved `ALTER MODIFY/ADD` queries logic. Now you cannot `ADD` column without type, `MODIFY` default expression does not change type of column and `MODIFY` type does not loose default expression value. Fixes [#8669](https://github.com/ClickHouse/ClickHouse/issues/8669). [#9227](https://github.com/ClickHouse/ClickHouse/pull/9227) ([alesapin](https://github.com/alesapin))
+* Require server to be restarted to apply the changes in logging configuration. This is a temporary workaround to avoid the bug where the server logs to a deleted log file (see [#8696](https://github.com/ClickHouse/ClickHouse/issues/8696)). [#8707](https://github.com/ClickHouse/ClickHouse/pull/8707) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* The setting `experimental_use_processors` is enabled by default. This setting enables usage of the new query pipeline. This is internal refactoring and we expect no visible changes. If you will see any issues, set it to back zero. [#8768](https://github.com/ClickHouse/ClickHouse/pull/8768) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### New Feature
+* Add `Avro` and `AvroConfluent` input/output formats [#8571](https://github.com/ClickHouse/ClickHouse/pull/8571) ([Andrew Onyshchuk](https://github.com/oandrew)) [#8957](https://github.com/ClickHouse/ClickHouse/pull/8957) ([Andrew Onyshchuk](https://github.com/oandrew)) [#8717](https://github.com/ClickHouse/ClickHouse/pull/8717) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Multi-threaded and non-blocking updates of expired keys in `cache` dictionaries (with optional permission to read old ones). [#8303](https://github.com/ClickHouse/ClickHouse/pull/8303) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Add query `ALTER ... MATERIALIZE TTL`. It runs mutation that forces to remove expired data by TTL and recalculates meta-information about TTL in all parts. [#8775](https://github.com/ClickHouse/ClickHouse/pull/8775) ([Anton Popov](https://github.com/CurtizJ))
+* Switch from HashJoin to MergeJoin (on disk) if needed [#9082](https://github.com/ClickHouse/ClickHouse/pull/9082) ([Artem Zuikov](https://github.com/4ertus2))
+* Added `MOVE PARTITION` command for `ALTER TABLE` [#4729](https://github.com/ClickHouse/ClickHouse/issues/4729) [#6168](https://github.com/ClickHouse/ClickHouse/pull/6168) ([Guillaume Tassery](https://github.com/YiuRULE))
+* Reloading storage configuration from configuration file on the fly. [#8594](https://github.com/ClickHouse/ClickHouse/pull/8594) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Allowed to change `storage_policy` to not less rich one. [#8107](https://github.com/ClickHouse/ClickHouse/pull/8107) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Added support for globs/wildcards for S3 storage and table function. [#8851](https://github.com/ClickHouse/ClickHouse/pull/8851) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Implement `bitAnd`, `bitOr`, `bitXor`, `bitNot` for `FixedString(N)` datatype. [#9091](https://github.com/ClickHouse/ClickHouse/pull/9091) ([Guillaume Tassery](https://github.com/YiuRULE))
+* Added function `bitCount`. This fixes [#8702](https://github.com/ClickHouse/ClickHouse/issues/8702). [#8708](https://github.com/ClickHouse/ClickHouse/pull/8708) ([alexey-milovidov](https://github.com/alexey-milovidov)) [#8749](https://github.com/ClickHouse/ClickHouse/pull/8749) ([ikopylov](https://github.com/ikopylov))
+* Add `generateRandom` table function to generate random rows with given schema. Allows to populate arbitrary test table with data. [#8994](https://github.com/ClickHouse/ClickHouse/pull/8994) ([Ilya Yatsishin](https://github.com/qoega))
+* `JSONEachRowFormat`: support special case when objects enclosed in top-level array. [#8860](https://github.com/ClickHouse/ClickHouse/pull/8860) ([Kruglov Pavel](https://github.com/Avogar))
+* Now it's possible to create a column with `DEFAULT` expression which depends on a column with default `ALIAS` expression. [#9489](https://github.com/ClickHouse/ClickHouse/pull/9489) ([alesapin](https://github.com/alesapin))
+* Allow to specify `--limit` more than the source data size in `clickhouse-obfuscator`. The data will repeat itself with different random seed. [#9155](https://github.com/ClickHouse/ClickHouse/pull/9155) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added `groupArraySample` function (similar to `groupArray`) with reservior sampling algorithm. [#8286](https://github.com/ClickHouse/ClickHouse/pull/8286) ([Amos Bird](https://github.com/amosbird))
+* Now you can monitor the size of update queue in `cache`/`complex_key_cache` dictionaries via system metrics. [#9413](https://github.com/ClickHouse/ClickHouse/pull/9413) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Allow to use CRLF as a line separator in CSV output format with setting `output_format_csv_crlf_end_of_line` is set to 1 [#8934](https://github.com/ClickHouse/ClickHouse/pull/8934) [#8935](https://github.com/ClickHouse/ClickHouse/pull/8935) [#8963](https://github.com/ClickHouse/ClickHouse/pull/8963) ([Mikhail Korotov](https://github.com/millb))
+* Implement more functions of the [H3](https://github.com/uber/h3) API: `h3GetBaseCell`, `h3HexAreaM2`, `h3IndexesAreNeighbors`, `h3ToChildren`, `h3ToString` and `stringToH3` [#8938](https://github.com/ClickHouse/ClickHouse/pull/8938) ([Nico Mandery](https://github.com/nmandery))
+* New setting introduced: `max_parser_depth` to control maximum stack size and allow large complex queries. This fixes [#6681](https://github.com/ClickHouse/ClickHouse/issues/6681) and [#7668](https://github.com/ClickHouse/ClickHouse/issues/7668). [#8647](https://github.com/ClickHouse/ClickHouse/pull/8647) ([Maxim Smirnov](https://github.com/qMBQx8GH))
+* Add a setting `force_optimize_skip_unused_shards` setting to throw if skipping of unused shards is not possible [#8805](https://github.com/ClickHouse/ClickHouse/pull/8805) ([Azat Khuzhin](https://github.com/azat))
+* Allow to configure multiple disks/volumes for storing data for send in `Distributed` engine [#8756](https://github.com/ClickHouse/ClickHouse/pull/8756) ([Azat Khuzhin](https://github.com/azat))
+* Support storage policy (`<tmp_policy>`) for storing temporary data. [#8750](https://github.com/ClickHouse/ClickHouse/pull/8750) ([Azat Khuzhin](https://github.com/azat))
+* Added `X-ClickHouse-Exception-Code` HTTP header that is set if exception was thrown before sending data. This implements [#4971](https://github.com/ClickHouse/ClickHouse/issues/4971). [#8786](https://github.com/ClickHouse/ClickHouse/pull/8786) ([Mikhail Korotov](https://github.com/millb))
+* Added function `ifNotFinite`. It is just a syntactic sugar: `ifNotFinite(x, y) = isFinite(x) ? x : y`. [#8710](https://github.com/ClickHouse/ClickHouse/pull/8710) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added `last_successful_update_time` column in `system.dictionaries` table [#9394](https://github.com/ClickHouse/ClickHouse/pull/9394) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Add `blockSerializedSize` function (size on disk without compression) [#8952](https://github.com/ClickHouse/ClickHouse/pull/8952) ([Azat Khuzhin](https://github.com/azat))
+* Add function `moduloOrZero` [#9358](https://github.com/ClickHouse/ClickHouse/pull/9358) ([hcz](https://github.com/hczhcz))
+* Added system tables `system.zeros` and `system.zeros_mt` as well as tale functions `zeros()` and `zeros_mt()`. Tables (and table functions) contain single column with name `zero` and type `UInt8`. This column contains zeros. It is needed for test purposes as the fastest method to generate many rows. This fixes [#6604](https://github.com/ClickHouse/ClickHouse/issues/6604) [#9593](https://github.com/ClickHouse/ClickHouse/pull/9593) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+
+#### Experimental Feature
+* Add new compact format of parts in `MergeTree`-family tables in which all columns are stored in one file. It helps to increase performance of small and frequent inserts. The old format (one file per column) is now called wide. Data storing format is controlled by settings `min_bytes_for_wide_part` and `min_rows_for_wide_part`. [#8290](https://github.com/ClickHouse/ClickHouse/pull/8290) ([Anton Popov](https://github.com/CurtizJ))
+* Support for S3 storage for `Log`, `TinyLog` and `StripeLog` tables. [#8862](https://github.com/ClickHouse/ClickHouse/pull/8862) ([Pavel Kovalenko](https://github.com/Jokser))
+
+#### Bug Fix
+* Fixed inconsistent whitespaces in log messages. [#9322](https://github.com/ClickHouse/ClickHouse/pull/9322) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix bug in which arrays of unnamed tuples were flattened as Nested structures on table creation. [#8866](https://github.com/ClickHouse/ClickHouse/pull/8866) ([achulkov2](https://github.com/achulkov2))
+* Fixed the issue when "Too many open files" error may happen if there are too many files matching glob pattern in `File` table or `file` table function. Now files are opened lazily. This fixes [#8857](https://github.com/ClickHouse/ClickHouse/issues/8857) [#8861](https://github.com/ClickHouse/ClickHouse/pull/8861) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* DROP TEMPORARY TABLE now drops only temporary table. [#8907](https://github.com/ClickHouse/ClickHouse/pull/8907) ([Vitaly Baranov](https://github.com/vitlibar))
+* Remove outdated partition when we shutdown the server or DETACH/ATTACH a table. [#8602](https://github.com/ClickHouse/ClickHouse/pull/8602) ([Guillaume Tassery](https://github.com/YiuRULE))
+* For how the default disk calculates the free space from `data` subdirectory. Fixed the issue when the amount of free space is not calculated correctly if the `data` directory is mounted to a separate device (rare case). This fixes [#7441](https://github.com/ClickHouse/ClickHouse/issues/7441) [#9257](https://github.com/ClickHouse/ClickHouse/pull/9257) ([Mikhail Korotov](https://github.com/millb))
+* Allow comma (cross) join with IN () inside. [#9251](https://github.com/ClickHouse/ClickHouse/pull/9251) ([Artem Zuikov](https://github.com/4ertus2))
+* Allow to rewrite CROSS to INNER JOIN if there's [NOT] LIKE operator in WHERE section. [#9229](https://github.com/ClickHouse/ClickHouse/pull/9229) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix possible incorrect result after `GROUP BY` with enabled setting `distributed_aggregation_memory_efficient`. Fixes [#9134](https://github.com/ClickHouse/ClickHouse/issues/9134). [#9289](https://github.com/ClickHouse/ClickHouse/pull/9289) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Found keys were counted as missed in metrics of cache dictionaries. [#9411](https://github.com/ClickHouse/ClickHouse/pull/9411) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Fix replication protocol incompatibility introduced in [#8598](https://github.com/ClickHouse/ClickHouse/issues/8598). [#9412](https://github.com/ClickHouse/ClickHouse/pull/9412) ([alesapin](https://github.com/alesapin))
+* Fixed race condition on `queue_task_handle` at the startup of `ReplicatedMergeTree` tables. [#9552](https://github.com/ClickHouse/ClickHouse/pull/9552) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* The token `NOT` did not work in `SHOW TABLES NOT LIKE` query [#8727](https://github.com/ClickHouse/ClickHouse/issues/8727) [#8940](https://github.com/ClickHouse/ClickHouse/pull/8940) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added range check to function `h3EdgeLengthM`. Without this check, buffer overflow is possible. [#8945](https://github.com/ClickHouse/ClickHouse/pull/8945) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed up a bug in batched calculations of ternary logical OPs on multiple arguments (more than 10). [#8718](https://github.com/ClickHouse/ClickHouse/pull/8718) ([Alexander Kazakov](https://github.com/Akazz))
+* Fix error of PREWHERE optimization, which could lead to segfaults or `Inconsistent number of columns got from MergeTreeRangeReader` exception. [#9024](https://github.com/ClickHouse/ClickHouse/pull/9024) ([Anton Popov](https://github.com/CurtizJ))
+* Fix unexpected `Timeout exceeded while reading from socket` exception, which randomly happens on secure connection before timeout actually exceeded and when query profiler is enabled. Also add `connect_timeout_with_failover_secure_ms` settings (default 100ms), which is similar to `connect_timeout_with_failover_ms`, but is used for secure connections (because SSL handshake is slower, than ordinary TCP connection) [#9026](https://github.com/ClickHouse/ClickHouse/pull/9026) ([tavplubix](https://github.com/tavplubix))
+* Fix bug with mutations finalization, when mutation may hang in state with `parts_to_do=0` and `is_done=0`. [#9022](https://github.com/ClickHouse/ClickHouse/pull/9022) ([alesapin](https://github.com/alesapin))
+* Use new ANY JOIN logic with `partial_merge_join` setting. It's possible to make `ANY|ALL|SEMI LEFT` and `ALL INNER` joins with `partial_merge_join=1` now. [#8932](https://github.com/ClickHouse/ClickHouse/pull/8932) ([Artem Zuikov](https://github.com/4ertus2))
+* Shard now clamps the settings got from the initiator to the shard's constaints instead of throwing an exception. This fix allows to send queries to a shard with another constraints. [#9447](https://github.com/ClickHouse/ClickHouse/pull/9447) ([Vitaly Baranov](https://github.com/vitlibar))
+* Fixed memory management problem in `MergeTreeReadPool`. [#8791](https://github.com/ClickHouse/ClickHouse/pull/8791) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix `toDecimal*OrNull()` functions family when called with string `e`. Fixes [#8312](https://github.com/ClickHouse/ClickHouse/issues/8312) [#8764](https://github.com/ClickHouse/ClickHouse/pull/8764) ([Artem Zuikov](https://github.com/4ertus2))
+* Make sure that `FORMAT Null` sends no data to the client. [#8767](https://github.com/ClickHouse/ClickHouse/pull/8767) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Fix bug that timestamp in `LiveViewBlockInputStream` will not updated. `LIVE VIEW` is an experimental feature. [#8644](https://github.com/ClickHouse/ClickHouse/pull/8644) ([vxider](https://github.com/Vxider)) [#8625](https://github.com/ClickHouse/ClickHouse/pull/8625) ([vxider](https://github.com/Vxider))
+* Fixed `ALTER MODIFY TTL` wrong behavior which did not allow to delete old TTL expressions. [#8422](https://github.com/ClickHouse/ClickHouse/pull/8422) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fixed UBSan report in MergeTreeIndexSet. This fixes [#9250](https://github.com/ClickHouse/ClickHouse/issues/9250) [#9365](https://github.com/ClickHouse/ClickHouse/pull/9365) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed the behaviour of `match` and `extract` functions when haystack has zero bytes. The behaviour was wrong when haystack was constant. This fixes [#9160](https://github.com/ClickHouse/ClickHouse/issues/9160) [#9163](https://github.com/ClickHouse/ClickHouse/pull/9163) ([alexey-milovidov](https://github.com/alexey-milovidov)) [#9345](https://github.com/ClickHouse/ClickHouse/pull/9345) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Avoid throwing from destructor in Apache Avro 3rd-party library. [#9066](https://github.com/ClickHouse/ClickHouse/pull/9066) ([Andrew Onyshchuk](https://github.com/oandrew))
+* Don't commit a batch polled from `Kafka` partially as it can lead to holes in data. [#8876](https://github.com/ClickHouse/ClickHouse/pull/8876) ([filimonov](https://github.com/filimonov))
+* Fix `joinGet` with nullable return types. [#8919](https://github.com/ClickHouse/ClickHouse/issues/8919) [#9014](https://github.com/ClickHouse/ClickHouse/pull/9014) ([Amos Bird](https://github.com/amosbird))
+* Fix data incompatibility when compressed with `T64` codec. [#9016](https://github.com/ClickHouse/ClickHouse/pull/9016) ([Artem Zuikov](https://github.com/4ertus2)) Fix data type ids in `T64` compression codec that leads to wrong (de)compression in affected versions. [#9033](https://github.com/ClickHouse/ClickHouse/pull/9033) ([Artem Zuikov](https://github.com/4ertus2))
+* Add setting `enable_early_constant_folding` and disable it in some cases that leads to errors. [#9010](https://github.com/ClickHouse/ClickHouse/pull/9010) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix pushdown predicate optimizer with VIEW and enable the test [#9011](https://github.com/ClickHouse/ClickHouse/pull/9011) ([Winter Zhang](https://github.com/zhang2014))
+* Fix segfault in `Merge` tables, that can happen when reading from `File` storages [#9387](https://github.com/ClickHouse/ClickHouse/pull/9387) ([tavplubix](https://github.com/tavplubix))
+* Added a check for storage policy in `ATTACH PARTITION FROM`, `REPLACE PARTITION`, `MOVE TO TABLE`. Otherwise it could make data of part inaccessible after restart and prevent ClickHouse to start. [#9383](https://github.com/ClickHouse/ClickHouse/pull/9383) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix alters if there is TTL set for table. [#8800](https://github.com/ClickHouse/ClickHouse/pull/8800) ([Anton Popov](https://github.com/CurtizJ))
+* Fix race condition that can happen when `SYSTEM RELOAD ALL DICTIONARIES` is executed while some dictionary is being modified/added/removed. [#8801](https://github.com/ClickHouse/ClickHouse/pull/8801) ([Vitaly Baranov](https://github.com/vitlibar))
+* In previous versions `Memory` database engine use empty data path, so tables are created in `path` directory (e.g. `/var/lib/clickhouse/`), not in data directory of database (e.g. `/var/lib/clickhouse/db_name`). [#8753](https://github.com/ClickHouse/ClickHouse/pull/8753) ([tavplubix](https://github.com/tavplubix))
+* Fixed wrong log messages about missing default disk or policy. [#9530](https://github.com/ClickHouse/ClickHouse/pull/9530) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix not(has()) for the bloom_filter index of array types. [#9407](https://github.com/ClickHouse/ClickHouse/pull/9407) ([achimbab](https://github.com/achimbab))
+* Allow first column(s) in a table with `Log` engine be an alias [#9231](https://github.com/ClickHouse/ClickHouse/pull/9231) ([Ivan](https://github.com/abyss7))
+* Fix order of ranges while reading from `MergeTree` table in one thread. It could lead to exceptions from `MergeTreeRangeReader` or wrong query results. [#9050](https://github.com/ClickHouse/ClickHouse/pull/9050) ([Anton Popov](https://github.com/CurtizJ))
+* Make `reinterpretAsFixedString` to return `FixedString` instead of `String`. [#9052](https://github.com/ClickHouse/ClickHouse/pull/9052) ([Andrew Onyshchuk](https://github.com/oandrew))
+* Avoid extremely rare cases when the user can get wrong error message (`Success` instead of detailed error description). [#9457](https://github.com/ClickHouse/ClickHouse/pull/9457) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Do not crash when using `Template` format with empty row template. [#8785](https://github.com/ClickHouse/ClickHouse/pull/8785) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Metadata files for system tables could be created in wrong place [#8653](https://github.com/ClickHouse/ClickHouse/pull/8653) ([tavplubix](https://github.com/tavplubix)) Fixes [#8581](https://github.com/ClickHouse/ClickHouse/issues/8581).
+* Fix data race on exception_ptr in cache dictionary [#8303](https://github.com/ClickHouse/ClickHouse/issues/8303). [#9379](https://github.com/ClickHouse/ClickHouse/pull/9379) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Do not throw an exception for query `ATTACH TABLE IF NOT EXISTS`. Previously it was thrown if table already exists, despite the `IF NOT EXISTS` clause. [#8967](https://github.com/ClickHouse/ClickHouse/pull/8967) ([Anton Popov](https://github.com/CurtizJ))
+* Fixed missing closing paren in exception message. [#8811](https://github.com/ClickHouse/ClickHouse/pull/8811) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Avoid message `Possible deadlock avoided` at the startup of clickhouse-client in interactive mode. [#9455](https://github.com/ClickHouse/ClickHouse/pull/9455) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed the issue when padding at the end of base64 encoded value can be malformed. Update base64 library. This fixes [#9491](https://github.com/ClickHouse/ClickHouse/issues/9491), closes [#9492](https://github.com/ClickHouse/ClickHouse/issues/9492) [#9500](https://github.com/ClickHouse/ClickHouse/pull/9500) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Prevent losing data in `Kafka` in rare cases when exception happens after reading suffix but before commit. Fixes [#9378](https://github.com/ClickHouse/ClickHouse/issues/9378) [#9507](https://github.com/ClickHouse/ClickHouse/pull/9507) ([filimonov](https://github.com/filimonov))
+* Fixed exception in `DROP TABLE IF EXISTS` [#8663](https://github.com/ClickHouse/ClickHouse/pull/8663) ([Nikita Vasilev](https://github.com/nikvas0))
+* Fix crash when a user tries to `ALTER MODIFY SETTING` for old-formated `MergeTree` table engines family. [#9435](https://github.com/ClickHouse/ClickHouse/pull/9435) ([alesapin](https://github.com/alesapin))
+* Support for UInt64 numbers that don't fit in Int64 in JSON-related functions. Update SIMDJSON to master. This fixes [#9209](https://github.com/ClickHouse/ClickHouse/issues/9209) [#9344](https://github.com/ClickHouse/ClickHouse/pull/9344) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed execution of inversed predicates when non-strictly monotinic functional index is used. [#9223](https://github.com/ClickHouse/ClickHouse/pull/9223) ([Alexander Kazakov](https://github.com/Akazz))
+* Don't try to fold `IN` constant in `GROUP BY` [#8868](https://github.com/ClickHouse/ClickHouse/pull/8868) ([Amos Bird](https://github.com/amosbird))
+* Fix bug in `ALTER DELETE` mutations which leads to index corruption. This fixes [#9019](https://github.com/ClickHouse/ClickHouse/issues/9019) and [#8982](https://github.com/ClickHouse/ClickHouse/issues/8982). Additionally fix extremely rare race conditions in `ReplicatedMergeTree` `ALTER` queries. [#9048](https://github.com/ClickHouse/ClickHouse/pull/9048) ([alesapin](https://github.com/alesapin))
+* When the setting `compile_expressions` is enabled, you can get `unexpected column` in `LLVMExecutableFunction` when we use `Nullable` type [#8910](https://github.com/ClickHouse/ClickHouse/pull/8910) ([Guillaume Tassery](https://github.com/YiuRULE))
+* Multiple fixes for `Kafka` engine: 1) fix duplicates that were appearing during consumer group rebalance. 2) Fix rare 'holes' appeared when data were polled from several partitions with one poll and committed partially (now we always process / commit the whole polled block of messages). 3) Fix flushes by block size (before that only flushing by timeout was working properly). 4) better subscription procedure (with assignment feedback). 5) Make tests work faster (with default intervals and timeouts). Due to the fact that data was not flushed by block size before (as it should according to documentation), that PR may lead to some performance degradation with default settings (due to more often & tinier flushes which are less optimal). If you encounter the performance issue after that change - please increase `kafka_max_block_size` in the table to the bigger value ( for example `CREATE TABLE ...Engine=Kafka ... SETTINGS ... kafka_max_block_size=524288`). Fixes [#7259](https://github.com/ClickHouse/ClickHouse/issues/7259) [#8917](https://github.com/ClickHouse/ClickHouse/pull/8917) ([filimonov](https://github.com/filimonov))
+* Fix `Parameter out of bound` exception in some queries after PREWHERE optimizations. [#8914](https://github.com/ClickHouse/ClickHouse/pull/8914) ([Baudouin Giard](https://github.com/bgiard))
+* Fixed the case of mixed-constness of arguments of function `arrayZip`. [#8705](https://github.com/ClickHouse/ClickHouse/pull/8705) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* When executing `CREATE` query, fold constant expressions in storage engine arguments. Replace empty database name with current database. Fixes [#6508](https://github.com/ClickHouse/ClickHouse/issues/6508), [#3492](https://github.com/ClickHouse/ClickHouse/issues/3492) [#9262](https://github.com/ClickHouse/ClickHouse/pull/9262) ([tavplubix](https://github.com/tavplubix))
+* Now it's not possible to create or add columns with simple cyclic aliases like `a DEFAULT b, b DEFAULT a`. [#9603](https://github.com/ClickHouse/ClickHouse/pull/9603) ([alesapin](https://github.com/alesapin))
+* Fixed a bug with double move which may corrupt original part. This is relevant if you use `ALTER TABLE MOVE` [#8680](https://github.com/ClickHouse/ClickHouse/pull/8680) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Allow `interval` identifier to correctly parse without backticks. Fixed issue when a query cannot be executed even if the `interval` identifier is enclosed in backticks or double quotes. This fixes [#9124](https://github.com/ClickHouse/ClickHouse/issues/9124). [#9142](https://github.com/ClickHouse/ClickHouse/pull/9142) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed fuzz test and incorrect behaviour of `bitTestAll`/`bitTestAny` functions. [#9143](https://github.com/ClickHouse/ClickHouse/pull/9143) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix possible crash/wrong number of rows in `LIMIT n WITH TIES` when there are a lot of rows equal to n'th row. [#9464](https://github.com/ClickHouse/ClickHouse/pull/9464) ([tavplubix](https://github.com/tavplubix))
+* Fix mutations with parts written with enabled `insert_quorum`. [#9463](https://github.com/ClickHouse/ClickHouse/pull/9463) ([alesapin](https://github.com/alesapin))
+* Fix data race at destruction of `Poco::HTTPServer`. It could happen when server is started and immediately shut down. [#9468](https://github.com/ClickHouse/ClickHouse/pull/9468) ([Anton Popov](https://github.com/CurtizJ))
+* Fix bug in which a misleading error message was shown when running `SHOW CREATE TABLE a_table_that_does_not_exist`. [#8899](https://github.com/ClickHouse/ClickHouse/pull/8899) ([achulkov2](https://github.com/achulkov2))
+* Fixed `Parameters are out of bound` exception in some rare cases when we have a constant in the `SELECT` clause when we have an `ORDER BY` and a `LIMIT` clause. [#8892](https://github.com/ClickHouse/ClickHouse/pull/8892) ([Guillaume Tassery](https://github.com/YiuRULE))
+* Fix mutations finalization, when already done mutation can have status `is_done=0`. [#9217](https://github.com/ClickHouse/ClickHouse/pull/9217) ([alesapin](https://github.com/alesapin))
+* Prevent from executing `ALTER ADD INDEX` for MergeTree tables with old syntax, because it does not work. [#8822](https://github.com/ClickHouse/ClickHouse/pull/8822) ([Mikhail Korotov](https://github.com/millb))
+* During server startup do not access table, which `LIVE VIEW` depends on, so server will be able to start. Also remove `LIVE VIEW` dependencies when detaching `LIVE VIEW`. `LIVE VIEW` is an experimental feature. [#8824](https://github.com/ClickHouse/ClickHouse/pull/8824) ([tavplubix](https://github.com/tavplubix))
+* Fix possible segfault in `MergeTreeRangeReader`, while executing `PREWHERE`. [#9106](https://github.com/ClickHouse/ClickHouse/pull/9106) ([Anton Popov](https://github.com/CurtizJ))
+* Fix possible mismatched checksums with column TTLs. [#9451](https://github.com/ClickHouse/ClickHouse/pull/9451) ([Anton Popov](https://github.com/CurtizJ))
+* Fixed a bug when parts were not being moved in background by TTL rules in case when there is only one volume. [#8672](https://github.com/ClickHouse/ClickHouse/pull/8672) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fixed the issue `Method createColumn() is not implemented for data type Set`. This fixes [#7799](https://github.com/ClickHouse/ClickHouse/issues/7799). [#8674](https://github.com/ClickHouse/ClickHouse/pull/8674) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Now we will try finalize mutations more frequently. [#9427](https://github.com/ClickHouse/ClickHouse/pull/9427) ([alesapin](https://github.com/alesapin))
+* Fix `intDiv` by minus one constant [#9351](https://github.com/ClickHouse/ClickHouse/pull/9351) ([hcz](https://github.com/hczhcz))
+* Fix possible race condition in `BlockIO`. [#9356](https://github.com/ClickHouse/ClickHouse/pull/9356) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix bug leading to server termination when trying to use / drop `Kafka` table created with wrong parameters. [#9513](https://github.com/ClickHouse/ClickHouse/pull/9513) ([filimonov](https://github.com/filimonov))
+* Added workaround if OS returns wrong result for `timer_create` function. [#8837](https://github.com/ClickHouse/ClickHouse/pull/8837) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed error in usage of `min_marks_for_seek` parameter. Fixed the error message when there is no sharding key in Distributed table and we try to skip unused shards. [#8908](https://github.com/ClickHouse/ClickHouse/pull/8908) ([Azat Khuzhin](https://github.com/azat))
+
+#### Improvement
+* Implement `ALTER MODIFY/DROP` queries on top of mutations for `ReplicatedMergeTree*` engines family. Now `ALTERS` blocks only at the metadata update stage, and don't block after that. [#8701](https://github.com/ClickHouse/ClickHouse/pull/8701) ([alesapin](https://github.com/alesapin))
+* Add ability to rewrite CROSS to INNER JOINs with `WHERE` section containing unqialified names. [#9512](https://github.com/ClickHouse/ClickHouse/pull/9512) ([Artem Zuikov](https://github.com/4ertus2))
+* Make `SHOW TABLES` and `SHOW DATABASES` queries support the `WHERE` expressions and `FROM`/`IN` [#9076](https://github.com/ClickHouse/ClickHouse/pull/9076) ([sundyli](https://github.com/sundy-li))
+* Added a setting `deduplicate_blocks_in_dependent_materialized_views`. [#9070](https://github.com/ClickHouse/ClickHouse/pull/9070) ([urykhy](https://github.com/urykhy))
+* After recent changes MySQL client started to print binary strings in hex thereby making them not readable ([#9032](https://github.com/ClickHouse/ClickHouse/issues/9032)). The workaround in ClickHouse is to mark string columns as UTF-8, which is not always, but usually the case. [#9079](https://github.com/ClickHouse/ClickHouse/pull/9079) ([Yuriy Baranov](https://github.com/yurriy))
+* Add support of String and FixedString keys for `sumMap` [#8903](https://github.com/ClickHouse/ClickHouse/pull/8903) ([Baudouin Giard](https://github.com/bgiard))
+* Support string keys in SummingMergeTree maps [#8933](https://github.com/ClickHouse/ClickHouse/pull/8933) ([Baudouin Giard](https://github.com/bgiard))
+* Signal termination of thread to the thread pool even if the thread has thrown exception [#8736](https://github.com/ClickHouse/ClickHouse/pull/8736) ([Ding Xiang Fei](https://github.com/dingxiangfei2009))
+* Allow to set `query_id` in `clickhouse-benchmark` [#9416](https://github.com/ClickHouse/ClickHouse/pull/9416) ([Anton Popov](https://github.com/CurtizJ))
+* Don't allow strange expressions in `ALTER TABLE ... PARTITION partition` query. This addresses [#7192](https://github.com/ClickHouse/ClickHouse/issues/7192) [#8835](https://github.com/ClickHouse/ClickHouse/pull/8835) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* The table `system.table_engines` now provides information about feature support (like `supports_ttl` or `supports_sort_order`). [#8830](https://github.com/ClickHouse/ClickHouse/pull/8830) ([Max Akhmedov](https://github.com/zlobober))
+* Enable `system.metric_log` by default. It will contain rows with values of ProfileEvents, CurrentMetrics collected with "collect_interval_milliseconds" interval (one second by default). The table is very small (usually in order of megabytes) and collecting this data by default is reasonable. [#9225](https://github.com/ClickHouse/ClickHouse/pull/9225) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Initialize query profiler for all threads in a group, e.g. it allows to fully profile insert-queries. Fixes [#6964](https://github.com/ClickHouse/ClickHouse/issues/6964) [#8874](https://github.com/ClickHouse/ClickHouse/pull/8874) ([Ivan](https://github.com/abyss7))
+* Now temporary `LIVE VIEW` is created by `CREATE LIVE VIEW name WITH TIMEOUT [42] ...` instead of `CREATE TEMPORARY LIVE VIEW ...`, because the previous syntax was not consistent with `CREATE TEMPORARY TABLE ...` [#9131](https://github.com/ClickHouse/ClickHouse/pull/9131) ([tavplubix](https://github.com/tavplubix))
+* Add text_log.level configuration parameter to limit entries that goes to `system.text_log` table [#8809](https://github.com/ClickHouse/ClickHouse/pull/8809) ([Azat Khuzhin](https://github.com/azat))
+* Allow to put downloaded part to a disks/volumes according to TTL rules [#8598](https://github.com/ClickHouse/ClickHouse/pull/8598) ([Vladimir Chebotarev](https://github.com/excitoon))
+* For external MySQL dictionaries, allow to mutualize MySQL connection pool to "share" them among dictionaries. This option significantly reduces the number of connections to MySQL servers. [#9409](https://github.com/ClickHouse/ClickHouse/pull/9409) ([Clément Rodriguez](https://github.com/clemrodriguez))
+* Show nearest query execution time for quantiles in `clickhouse-benchmark` output instead of interpolated values. It's better to show values that correspond to the execution time of some queries. [#8712](https://github.com/ClickHouse/ClickHouse/pull/8712) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Possibility to add key & timestamp for the message when inserting data to Kafka. Fixes [#7198](https://github.com/ClickHouse/ClickHouse/issues/7198) [#8969](https://github.com/ClickHouse/ClickHouse/pull/8969) ([filimonov](https://github.com/filimonov))
+* If server is run from terminal, highlight thread number, query id and log priority by colors. This is for improved readability of correlated log messages for developers. [#8961](https://github.com/ClickHouse/ClickHouse/pull/8961) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Better exception message while loading tables for `Ordinary` database. [#9527](https://github.com/ClickHouse/ClickHouse/pull/9527) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Implement `arraySlice` for arrays with aggregate function states. This fixes [#9388](https://github.com/ClickHouse/ClickHouse/issues/9388) [#9391](https://github.com/ClickHouse/ClickHouse/pull/9391) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Allow constant functions and constant arrays to be used on the right side of IN operator. [#8813](https://github.com/ClickHouse/ClickHouse/pull/8813) ([Anton Popov](https://github.com/CurtizJ))
+* If zookeeper exception has happened while fetching data for system.replicas, display it in a separate column. This implements [#9137](https://github.com/ClickHouse/ClickHouse/issues/9137) [#9138](https://github.com/ClickHouse/ClickHouse/pull/9138) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Atomically remove MergeTree data parts on destroy. [#8402](https://github.com/ClickHouse/ClickHouse/pull/8402) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Support row-level security for Distributed tables. [#8926](https://github.com/ClickHouse/ClickHouse/pull/8926) ([Ivan](https://github.com/abyss7))
+* Now we recognize suffix (like KB, KiB...) in settings values. [#8072](https://github.com/ClickHouse/ClickHouse/pull/8072) ([Mikhail Korotov](https://github.com/millb))
+* Prevent out of memory while constructing result of a large JOIN. [#8637](https://github.com/ClickHouse/ClickHouse/pull/8637) ([Artem Zuikov](https://github.com/4ertus2))
+* Added names of clusters to suggestions in interactive mode in `clickhouse-client`. [#8709](https://github.com/ClickHouse/ClickHouse/pull/8709) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Initialize query profiler for all threads in a group, e.g. it allows to fully profile insert-queries [#8820](https://github.com/ClickHouse/ClickHouse/pull/8820) ([Ivan](https://github.com/abyss7))
+* Added column `exception_code` in `system.query_log` table. [#8770](https://github.com/ClickHouse/ClickHouse/pull/8770) ([Mikhail Korotov](https://github.com/millb))
+* Enabled MySQL compatibility server on port `9004` in the default server configuration file. Fixed password generation command in the example in configuration. [#8771](https://github.com/ClickHouse/ClickHouse/pull/8771) ([Yuriy Baranov](https://github.com/yurriy))
+* Prevent abort on shutdown if the filesystem is readonly. This fixes [#9094](https://github.com/ClickHouse/ClickHouse/issues/9094) [#9100](https://github.com/ClickHouse/ClickHouse/pull/9100) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Better exception message when length is required in HTTP POST query. [#9453](https://github.com/ClickHouse/ClickHouse/pull/9453) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add `_path` and `_file` virtual columns to `HDFS` and `File` engines and `hdfs` and `file` table functions [#8489](https://github.com/ClickHouse/ClickHouse/pull/8489) ([Olga Khvostikova](https://github.com/stavrolia))
+* Fix error `Cannot find column` while inserting into `MATERIALIZED VIEW` in case if new column was added to view's internal table. [#8766](https://github.com/ClickHouse/ClickHouse/pull/8766) [#8788](https://github.com/ClickHouse/ClickHouse/pull/8788) ([vzakaznikov](https://github.com/vzakaznikov)) [#8788](https://github.com/ClickHouse/ClickHouse/issues/8788) [#8806](https://github.com/ClickHouse/ClickHouse/pull/8806) ([Nikolai Kochetov](https://github.com/KochetovNicolai)) [#8803](https://github.com/ClickHouse/ClickHouse/pull/8803) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix progress over native client-server protocol, by send progress after final update (like logs). This may be relevant only to some third-party tools that are using native protocol. [#9495](https://github.com/ClickHouse/ClickHouse/pull/9495) ([Azat Khuzhin](https://github.com/azat))
+* Add a system metric tracking the number of client connections using MySQL protocol ([#9013](https://github.com/ClickHouse/ClickHouse/issues/9013)). [#9015](https://github.com/ClickHouse/ClickHouse/pull/9015) ([Eugene Klimov](https://github.com/Slach))
+* From now on, HTTP responses will have `X-ClickHouse-Timezone` header set to the same timezone value that `SELECT timezone()` would report. [#9493](https://github.com/ClickHouse/ClickHouse/pull/9493) ([Denis Glazachev](https://github.com/traceon))
+
+#### Performance Improvement
+* Improve performance of analysing index with IN [#9261](https://github.com/ClickHouse/ClickHouse/pull/9261) ([Anton Popov](https://github.com/CurtizJ))
+* Simpler and more efficient code in Logical Functions + code cleanups. A followup to [#8718](https://github.com/ClickHouse/ClickHouse/issues/8718) [#8728](https://github.com/ClickHouse/ClickHouse/pull/8728) ([Alexander Kazakov](https://github.com/Akazz))
+* Overall performance improvement (in range of 5%..200% for affected queries) by ensuring even more strict aliasing with C++20 features. [#9304](https://github.com/ClickHouse/ClickHouse/pull/9304) ([Amos Bird](https://github.com/amosbird))
+* More strict aliasing for inner loops of comparison functions. [#9327](https://github.com/ClickHouse/ClickHouse/pull/9327) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* More strict aliasing for inner loops of arithmetic functions. [#9325](https://github.com/ClickHouse/ClickHouse/pull/9325) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* A ~3 times faster implementation for ColumnVector::replicate(), via which ColumnConst::convertToFullColumn() is implemented. Also will be useful in tests when materializing constants. [#9293](https://github.com/ClickHouse/ClickHouse/pull/9293) ([Alexander Kazakov](https://github.com/Akazz))
+* Another minor performance improvement to `ColumnVector::replicate()` (this speeds up the `materialize` function and higher order functions) an even further improvement to [#9293](https://github.com/ClickHouse/ClickHouse/issues/9293) [#9442](https://github.com/ClickHouse/ClickHouse/pull/9442) ([Alexander Kazakov](https://github.com/Akazz))
+* Improved performance of `stochasticLinearRegression` aggregate function. This patch is contributed by Intel. [#8652](https://github.com/ClickHouse/ClickHouse/pull/8652) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Improve performance of `reinterpretAsFixedString` function. [#9342](https://github.com/ClickHouse/ClickHouse/pull/9342) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Do not send blocks to client for `Null` format in processors pipeline. [#8797](https://github.com/ClickHouse/ClickHouse/pull/8797) ([Nikolai Kochetov](https://github.com/KochetovNicolai)) [#8767](https://github.com/ClickHouse/ClickHouse/pull/8767) ([Alexander Kuzmenkov](https://github.com/akuzm))
+
+#### Build/Testing/Packaging Improvement
+* Exception handling now works correctly on Windows Subsystem for Linux. See https://github.com/ClickHouse-Extras/libunwind/pull/3 This fixes [#6480](https://github.com/ClickHouse/ClickHouse/issues/6480) [#9564](https://github.com/ClickHouse/ClickHouse/pull/9564) ([sobolevsv](https://github.com/sobolevsv))
+* Replace `readline` with `replxx` for interactive line editing in `clickhouse-client` [#8416](https://github.com/ClickHouse/ClickHouse/pull/8416) ([Ivan](https://github.com/abyss7))
+* Better build time and less template instantiations in FunctionsComparison. [#9324](https://github.com/ClickHouse/ClickHouse/pull/9324) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added integration with `clang-tidy` in CI. See also [#6044](https://github.com/ClickHouse/ClickHouse/issues/6044) [#9566](https://github.com/ClickHouse/ClickHouse/pull/9566) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Now we link ClickHouse in CI using `lld` even for `gcc`. [#9049](https://github.com/ClickHouse/ClickHouse/pull/9049) ([alesapin](https://github.com/alesapin))
+* Allow to randomize thread scheduling and insert glitches when `THREAD_FUZZER_*` environment variables are set. This helps testing. [#9459](https://github.com/ClickHouse/ClickHouse/pull/9459) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Enable secure sockets in stateless tests [#9288](https://github.com/ClickHouse/ClickHouse/pull/9288) ([tavplubix](https://github.com/tavplubix))
+* Make SPLIT_SHARED_LIBRARIES=OFF more robust [#9156](https://github.com/ClickHouse/ClickHouse/pull/9156) ([Azat Khuzhin](https://github.com/azat))
+* Make "performance_introspection_and_logging" test reliable to random server stuck. This may happen in CI environment. See also [#9515](https://github.com/ClickHouse/ClickHouse/issues/9515) [#9528](https://github.com/ClickHouse/ClickHouse/pull/9528) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Validate XML in style check. [#9550](https://github.com/ClickHouse/ClickHouse/pull/9550) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed race condition in test `00738_lock_for_inner_table`. This test relied on sleep. [#9555](https://github.com/ClickHouse/ClickHouse/pull/9555) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Remove performance tests of type `once`. This is needed to run all performance tests in statistical comparison mode (more reliable). [#9557](https://github.com/ClickHouse/ClickHouse/pull/9557) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added performance test for arithmetic functions. [#9326](https://github.com/ClickHouse/ClickHouse/pull/9326) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added performance test for `sumMap` and `sumMapWithOverflow` aggregate functions. Follow-up for [#8933](https://github.com/ClickHouse/ClickHouse/issues/8933) [#8947](https://github.com/ClickHouse/ClickHouse/pull/8947) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Ensure style of ErrorCodes by style check. [#9370](https://github.com/ClickHouse/ClickHouse/pull/9370) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add script for tests history. [#8796](https://github.com/ClickHouse/ClickHouse/pull/8796) ([alesapin](https://github.com/alesapin))
+* Add GCC warning `-Wsuggest-override` to locate and fix all places where `override` keyword must be used. [#8760](https://github.com/ClickHouse/ClickHouse/pull/8760) ([kreuzerkrieg](https://github.com/kreuzerkrieg))
+* Ignore weak symbol under Mac OS X because it must be defined [#9538](https://github.com/ClickHouse/ClickHouse/pull/9538) ([Deleted user](https://github.com/ghost))
+* Normalize running time of some queries in performance tests. This is done in preparation to run all the performance tests in comparison mode. [#9565](https://github.com/ClickHouse/ClickHouse/pull/9565) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix some tests to support pytest with query tests [#9062](https://github.com/ClickHouse/ClickHouse/pull/9062) ([Ivan](https://github.com/abyss7))
+* Enable SSL in build with MSan, so server will not fail at startup when running stateless tests [#9531](https://github.com/ClickHouse/ClickHouse/pull/9531) ([tavplubix](https://github.com/tavplubix))
+* Fix database substitution in test results [#9384](https://github.com/ClickHouse/ClickHouse/pull/9384) ([Ilya Yatsishin](https://github.com/qoega))
+* Build fixes for miscellaneous platforms [#9381](https://github.com/ClickHouse/ClickHouse/pull/9381) ([proller](https://github.com/proller)) [#8755](https://github.com/ClickHouse/ClickHouse/pull/8755) ([proller](https://github.com/proller)) [#8631](https://github.com/ClickHouse/ClickHouse/pull/8631) ([proller](https://github.com/proller))
+* Added disks section to stateless-with-coverage test docker image [#9213](https://github.com/ClickHouse/ClickHouse/pull/9213) ([Pavel Kovalenko](https://github.com/Jokser))
+* Get rid of in-source-tree files when building with GRPC [#9588](https://github.com/ClickHouse/ClickHouse/pull/9588) ([Amos Bird](https://github.com/amosbird))
+* Slightly faster build time by removing SessionCleaner from Context. Make the code of SessionCleaner more simple. [#9232](https://github.com/ClickHouse/ClickHouse/pull/9232) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Updated checking for hung queries in clickhouse-test script [#8858](https://github.com/ClickHouse/ClickHouse/pull/8858) ([Alexander Kazakov](https://github.com/Akazz))
+* Removed some useless files from repository. [#8843](https://github.com/ClickHouse/ClickHouse/pull/8843) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Changed type of math perftests from `once` to `loop`. [#8783](https://github.com/ClickHouse/ClickHouse/pull/8783) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Add docker image which allows to build interactive code browser HTML report for our codebase. [#8781](https://github.com/ClickHouse/ClickHouse/pull/8781) ([alesapin](https://github.com/alesapin)) See [Woboq Code Browser](https://clickhouse-test-reports.s3.yandex.net/codebrowser/ClickHouse/dbms/index.html)
+* Suppress some test failures under MSan. [#8780](https://github.com/ClickHouse/ClickHouse/pull/8780) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Speedup "exception while insert" test. This test often time out in debug-with-coverage build. [#8711](https://github.com/ClickHouse/ClickHouse/pull/8711) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Updated `libcxx` and `libcxxabi` to master. In preparation to [#9304](https://github.com/ClickHouse/ClickHouse/issues/9304) [#9308](https://github.com/ClickHouse/ClickHouse/pull/9308) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix flacky test `00910_zookeeper_test_alter_compression_codecs`. [#9525](https://github.com/ClickHouse/ClickHouse/pull/9525) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Clean up duplicated linker flags. Make sure the linker won't look up an unexpected symbol. [#9433](https://github.com/ClickHouse/ClickHouse/pull/9433) ([Amos Bird](https://github.com/amosbird))
+* Add `clickhouse-odbc` driver into test images. This allows to test interaction of ClickHouse with ClickHouse via its own ODBC driver. [#9348](https://github.com/ClickHouse/ClickHouse/pull/9348) ([filimonov](https://github.com/filimonov))
+* Fix several bugs in unit tests. [#9047](https://github.com/ClickHouse/ClickHouse/pull/9047) ([alesapin](https://github.com/alesapin))
+* Enable `-Wmissing-include-dirs` GCC warning to eliminate all non-existing includes - mostly as a result of CMake scripting errors [#8704](https://github.com/ClickHouse/ClickHouse/pull/8704) ([kreuzerkrieg](https://github.com/kreuzerkrieg))
+* Describe reasons if query profiler cannot work. This is intended for [#9049](https://github.com/ClickHouse/ClickHouse/issues/9049) [#9144](https://github.com/ClickHouse/ClickHouse/pull/9144) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Update OpenSSL to upstream master. Fixed the issue when TLS connections may fail with the message `OpenSSL SSL_read: error:14094438:SSL routines:ssl3_read_bytes:tlsv1 alert internal error` and `SSL Exception: error:2400006E:random number generator::error retrieving entropy`. The issue was present in version 20.1. [#8956](https://github.com/ClickHouse/ClickHouse/pull/8956) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Update Dockerfile for server [#8893](https://github.com/ClickHouse/ClickHouse/pull/8893) ([Ilya Mazaev](https://github.com/ne-ray))
+* Minor fixes in build-gcc-from-sources script [#8774](https://github.com/ClickHouse/ClickHouse/pull/8774) ([Michael Nacharov](https://github.com/mnach))
+* Replace `numbers` to `zeros` in perftests where `number` column is not used. This will lead to more clean test results. [#9600](https://github.com/ClickHouse/ClickHouse/pull/9600) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix stack overflow issue when using initializer_list in Column constructors. [#9367](https://github.com/ClickHouse/ClickHouse/pull/9367) ([Deleted user](https://github.com/ghost))
+* Upgrade librdkafka to v1.3.0. Enable bundled `rdkafka` and `gsasl` libraries on Mac OS X. [#9000](https://github.com/ClickHouse/ClickHouse/pull/9000) ([Andrew Onyshchuk](https://github.com/oandrew))
+* build fix on GCC 9.2.0 [#9306](https://github.com/ClickHouse/ClickHouse/pull/9306) ([vxider](https://github.com/Vxider))
+
+
+## ClickHouse release v20.1
+
+### ClickHouse release v20.1.16.120-stable 2020-60-26
+
+#### Bug Fix
+
+* Fix rare crash caused by using `Nullable` column in prewhere condition. Continuation of [#11608](https://github.com/ClickHouse/ClickHouse/issues/11608). [#11869](https://github.com/ClickHouse/ClickHouse/pull/11869) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Don't allow arrayJoin inside higher order functions. It was leading to broken protocol synchronization. This closes [#3933](https://github.com/ClickHouse/ClickHouse/issues/3933). [#11846](https://github.com/ClickHouse/ClickHouse/pull/11846) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix unexpected behaviour of queries like `SELECT *, xyz.*` which were success while an error expected. [#11753](https://github.com/ClickHouse/ClickHouse/pull/11753) ([hexiaoting](https://github.com/hexiaoting)).
+* Fixed LOGICAL_ERROR caused by wrong type deduction of complex literals in Values input format. [#11732](https://github.com/ClickHouse/ClickHouse/pull/11732) ([tavplubix](https://github.com/tavplubix)).
+* Fix `ORDER BY ... WITH FILL` over const columns. [#11697](https://github.com/ClickHouse/ClickHouse/pull/11697) ([Anton Popov](https://github.com/CurtizJ)).
+* Pass proper timeouts when communicating with XDBC bridge. Recently timeouts were not respected when checking bridge liveness and receiving meta info. [#11690](https://github.com/ClickHouse/ClickHouse/pull/11690) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add support for regular expressions with case-insensitive flags. This fixes [#11101](https://github.com/ClickHouse/ClickHouse/issues/11101) and fixes [#11506](https://github.com/ClickHouse/ClickHouse/issues/11506). [#11649](https://github.com/ClickHouse/ClickHouse/pull/11649) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bloom filters for String (data skipping indices). [#11638](https://github.com/ClickHouse/ClickHouse/pull/11638) ([Azat Khuzhin](https://github.com/azat)).
+* Fix rare crash caused by using `Nullable` column in prewhere condition. (Probably it is connected with [#11572](https://github.com/ClickHouse/ClickHouse/issues/11572) somehow). [#11608](https://github.com/ClickHouse/ClickHouse/pull/11608) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix wrong exit code of the clickhouse-client, when exception.code() % 256 = 0. [#11601](https://github.com/ClickHouse/ClickHouse/pull/11601) ([filimonov](https://github.com/filimonov)).
+* Fix trivial error in log message about "Mark cache size was lowered" at server startup. This closes [#11399](https://github.com/ClickHouse/ClickHouse/issues/11399). [#11589](https://github.com/ClickHouse/ClickHouse/pull/11589) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now clickhouse-server docker container will prefer IPv6 checking server aliveness. [#11550](https://github.com/ClickHouse/ClickHouse/pull/11550) ([Ivan Starkov](https://github.com/istarkov)).
+* Fix memory leak when exception is thrown in the middle of aggregation with -State functions. This fixes [#8995](https://github.com/ClickHouse/ClickHouse/issues/8995). [#11496](https://github.com/ClickHouse/ClickHouse/pull/11496) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix usage of primary key wrapped into a function with 'FINAL' modifier and 'ORDER BY' optimization. [#10715](https://github.com/ClickHouse/ClickHouse/pull/10715) ([Anton Popov](https://github.com/CurtizJ)).
+
+
+### ClickHouse release v20.1.15.109-stable 2020-06-19
+
+#### Bug Fix
+
+* Fix excess lock for structure during alter. [#11790](https://github.com/ClickHouse/ClickHouse/pull/11790) ([alesapin](https://github.com/alesapin)).
+
+
+### ClickHouse release v20.1.14.107-stable 2020-06-11
+
+#### Bug Fix
+
+* Fix error `Size of offsets does not match size of column` for queries with `PREWHERE column in (subquery)` and `ARRAY JOIN`. [#11580](https://github.com/ClickHouse/ClickHouse/pull/11580) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+
+
+### ClickHouse release v20.1.13.105-stable 2020-06-10
+
+#### Bug Fix
+
+* Fix the error `Data compressed with different methods` that can happen if `min_bytes_to_use_direct_io` is enabled and PREWHERE is active and using SAMPLE or high number of threads. This fixes [#11539](https://github.com/ClickHouse/ClickHouse/issues/11539). [#11540](https://github.com/ClickHouse/ClickHouse/pull/11540) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix return compressed size for codecs. [#11448](https://github.com/ClickHouse/ClickHouse/pull/11448) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix server crash when a column has compression codec with non-literal arguments. Fixes [#11365](https://github.com/ClickHouse/ClickHouse/issues/11365). [#11431](https://github.com/ClickHouse/ClickHouse/pull/11431) ([alesapin](https://github.com/alesapin)).
+* Fix pointInPolygon with nan as point. Fixes [#11375](https://github.com/ClickHouse/ClickHouse/issues/11375). [#11421](https://github.com/ClickHouse/ClickHouse/pull/11421) ([Alexey Ilyukhov](https://github.com/livace)).
+* Fixed geohashesInBox with arguments outside of latitude/longitude range. [#11403](https://github.com/ClickHouse/ClickHouse/pull/11403) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fix possible `Pipeline stuck` error for queries with external sort and limit. Fixes [#11359](https://github.com/ClickHouse/ClickHouse/issues/11359). [#11366](https://github.com/ClickHouse/ClickHouse/pull/11366) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix crash in `quantilesExactWeightedArray`. [#11337](https://github.com/ClickHouse/ClickHouse/pull/11337) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Make writing to `MATERIALIZED VIEW` with setting `parallel_view_processing = 1` parallel again. Fixes [#10241](https://github.com/ClickHouse/ClickHouse/issues/10241). [#11330](https://github.com/ClickHouse/ClickHouse/pull/11330) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix visitParamExtractRaw when extracted JSON has strings with unbalanced { or [. [#11318](https://github.com/ClickHouse/ClickHouse/pull/11318) ([Ewout](https://github.com/devwout)).
+* Fix very rare race condition in ThreadPool. [#11314](https://github.com/ClickHouse/ClickHouse/pull/11314) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix potential uninitialized memory in conversion. Example: `SELECT toIntervalSecond(now64())`. [#11311](https://github.com/ClickHouse/ClickHouse/pull/11311) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix the issue when index analysis cannot work if a table has Array column in primary key and if a query is filtering by this column with `empty` or `notEmpty` functions. This fixes [#11286](https://github.com/ClickHouse/ClickHouse/issues/11286). [#11303](https://github.com/ClickHouse/ClickHouse/pull/11303) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix bug when query speed estimation can be incorrect and the limit of `min_execution_speed` may not work or work incorrectly if the query is throttled by `max_network_bandwidth`, `max_execution_speed` or `priority` settings. Change the default value of `timeout_before_checking_execution_speed` to non-zero, because otherwise the settings `min_execution_speed` and `max_execution_speed` have no effect. This fixes [#11297](https://github.com/ClickHouse/ClickHouse/issues/11297). This fixes [#5732](https://github.com/ClickHouse/ClickHouse/issues/5732). This fixes [#6228](https://github.com/ClickHouse/ClickHouse/issues/6228). Usability improvement: avoid concatenation of exception message with progress bar in `clickhouse-client`. [#11296](https://github.com/ClickHouse/ClickHouse/pull/11296) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash while reading malformed data in Protobuf format. This fixes [#5957](https://github.com/ClickHouse/ClickHouse/issues/5957), fixes [#11203](https://github.com/ClickHouse/ClickHouse/issues/11203). [#11258](https://github.com/ClickHouse/ClickHouse/pull/11258) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix possible error `Cannot capture column` for higher-order functions with `Array(Array(LowCardinality))` captured argument. [#11185](https://github.com/ClickHouse/ClickHouse/pull/11185) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* If data skipping index is dependent on columns that are going to be modified during background merge (for SummingMergeTree, AggregatingMergeTree as well as for TTL GROUP BY), it was calculated incorrectly. This issue is fixed by moving index calculation after merge so the index is calculated on merged data. [#11162](https://github.com/ClickHouse/ClickHouse/pull/11162) ([Azat Khuzhin](https://github.com/azat)).
+* Remove logging from mutation finalization task if nothing was finalized. [#11109](https://github.com/ClickHouse/ClickHouse/pull/11109) ([alesapin](https://github.com/alesapin)).
+* Fixed parseDateTime64BestEffort argument resolution bugs. [#10925](https://github.com/ClickHouse/ClickHouse/issues/10925). [#11038](https://github.com/ClickHouse/ClickHouse/pull/11038) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fix incorrect raw data size in method getRawData(). [#10964](https://github.com/ClickHouse/ClickHouse/pull/10964) ([Igr](https://github.com/ObjatieGroba)).
+* Fix backward compatibility with tuples in Distributed tables. [#10889](https://github.com/ClickHouse/ClickHouse/pull/10889) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix SIGSEGV in StringHashTable (if such key does not exist). [#10870](https://github.com/ClickHouse/ClickHouse/pull/10870) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed bug in `ReplicatedMergeTree` which might cause some `ALTER` on `OPTIMIZE` query to hang waiting for some replica after it become inactive. [#10849](https://github.com/ClickHouse/ClickHouse/pull/10849) ([tavplubix](https://github.com/tavplubix)).
+* Fix columns order after Block::sortColumns() (also add a test that shows that it affects some real use case - Buffer engine). [#10826](https://github.com/ClickHouse/ClickHouse/pull/10826) ([Azat Khuzhin](https://github.com/azat)).
+* Fix the issue with ODBC bridge when no quoting of identifiers is requested. This fixes [#7984](https://github.com/ClickHouse/ClickHouse/issues/7984). [#10821](https://github.com/ClickHouse/ClickHouse/pull/10821) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix UBSan and MSan report in DateLUT. [#10798](https://github.com/ClickHouse/ClickHouse/pull/10798) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* - Make use of `src_type` for correct type conversion in key conditions. Fixes [#6287](https://github.com/ClickHouse/ClickHouse/issues/6287). [#10791](https://github.com/ClickHouse/ClickHouse/pull/10791) ([Andrew Onyshchuk](https://github.com/oandrew)).
+* Fix `parallel_view_processing` behavior. Now all insertions into `MATERIALIZED VIEW` without exception should be finished if exception happened. Fixes [#10241](https://github.com/ClickHouse/ClickHouse/issues/10241). [#10757](https://github.com/ClickHouse/ClickHouse/pull/10757) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix combinator -OrNull and -OrDefault when combined with -State. [#10741](https://github.com/ClickHouse/ClickHouse/pull/10741) ([hcz](https://github.com/hczhcz)).
+* Fix disappearing totals. Totals could have being filtered if query had had join or subquery with external where condition. Fixes [#10674](https://github.com/ClickHouse/ClickHouse/issues/10674). [#10698](https://github.com/ClickHouse/ClickHouse/pull/10698) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix multiple usages of `IN` operator with the identical set in one query. [#10686](https://github.com/ClickHouse/ClickHouse/pull/10686) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix order of parameters in AggregateTransform constructor. [#10667](https://github.com/ClickHouse/ClickHouse/pull/10667) ([palasonic1](https://github.com/palasonic1)).
+* Fix the lack of parallel execution of remote queries with `distributed_aggregation_memory_efficient` enabled. Fixes [#10655](https://github.com/ClickHouse/ClickHouse/issues/10655). [#10664](https://github.com/ClickHouse/ClickHouse/pull/10664) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix predicates optimization for distributed queries (`enable_optimize_predicate_expression=1`) for queries with `HAVING` section (i.e. when filtering on the server initiator is required), by preserving the order of expressions (and this is enough to fix), and also force aggregator use column names over indexes. Fixes: [#10613](https://github.com/ClickHouse/ClickHouse/issues/10613), [#11413](https://github.com/ClickHouse/ClickHouse/issues/11413). [#10621](https://github.com/ClickHouse/ClickHouse/pull/10621) ([Azat Khuzhin](https://github.com/azat)).
+* Fix error `the BloomFilter false positive must be a double number between 0 and 1` [#10551](https://github.com/ClickHouse/ClickHouse/issues/10551). [#10569](https://github.com/ClickHouse/ClickHouse/pull/10569) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix SELECT of column ALIAS which default expression type different from column type. [#10563](https://github.com/ClickHouse/ClickHouse/pull/10563) ([Azat Khuzhin](https://github.com/azat)).
+* * Implemented comparison between DateTime64 and String values (just like for DateTime). [#10560](https://github.com/ClickHouse/ClickHouse/pull/10560) ([Vasily Nemkov](https://github.com/Enmk)).
+
+
+### ClickHouse release v20.1.12.86, 2020-05-26
+
+#### Bug Fix
+
+* Fixed incompatibility of two-level aggregation between versions 20.1 and earlier. This incompatibility happens when different versions of ClickHouse are used on initiator node and remote nodes and the size of GROUP BY result is large and aggregation is performed by a single String field. It leads to several unmerged rows for a single key in result. [#10952](https://github.com/ClickHouse/ClickHouse/pull/10952) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed data corruption for `LowCardinality(FixedString)` key column in `SummingMergeTree` which could have happened after merge. Fixes [#10489](https://github.com/ClickHouse/ClickHouse/issues/10489). [#10721](https://github.com/ClickHouse/ClickHouse/pull/10721) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed bug, which causes http requests stuck on client close when `readonly=2` and `cancel_http_readonly_queries_on_client_close=1`. Fixes [#7939](https://github.com/ClickHouse/ClickHouse/issues/7939), [#7019](https://github.com/ClickHouse/ClickHouse/issues/7019), [#7736](https://github.com/ClickHouse/ClickHouse/issues/7736), [#7091](https://github.com/ClickHouse/ClickHouse/issues/7091). [#10684](https://github.com/ClickHouse/ClickHouse/pull/10684) ([tavplubix](https://github.com/tavplubix)).
+* Fixed a bug when on `SYSTEM DROP DNS CACHE` query also drop caches, which are used to check if user is allowed to connect from some IP addresses. [#10608](https://github.com/ClickHouse/ClickHouse/pull/10608) ([tavplubix](https://github.com/tavplubix)).
+* Fixed incorrect scalar results inside inner query of `MATERIALIZED VIEW` in case if this query contained dependent table. [#10603](https://github.com/ClickHouse/ClickHouse/pull/10603) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed the situation when mutation finished all parts, but hung up in `is_done=0`. [#10526](https://github.com/ClickHouse/ClickHouse/pull/10526) ([alesapin](https://github.com/alesapin)).
+* Fixed overflow at beginning of unix epoch for timezones with fractional offset from UTC. This fixes [#9335](https://github.com/ClickHouse/ClickHouse/issues/9335). [#10513](https://github.com/ClickHouse/ClickHouse/pull/10513) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed improper shutdown of Distributed storage. [#10491](https://github.com/ClickHouse/ClickHouse/pull/10491) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed numeric overflow in `simpleLinearRegression` over large integers. [#10474](https://github.com/ClickHouse/ClickHouse/pull/10474) ([hcz](https://github.com/hczhcz)).
+* Fixed removing metadata directory when attach database fails. [#10442](https://github.com/ClickHouse/ClickHouse/pull/10442) ([Winter Zhang](https://github.com/zhang2014)).
+* Added a check of number and type of arguments when creating `BloomFilter` index [#9623](https://github.com/ClickHouse/ClickHouse/issues/9623). [#10431](https://github.com/ClickHouse/ClickHouse/pull/10431) ([Winter Zhang](https://github.com/zhang2014)).
+* Fixed the issue when a query with `ARRAY JOIN`, `ORDER BY` and `LIMIT` may return incomplete result. This fixes [#10226](https://github.com/ClickHouse/ClickHouse/issues/10226). [#10427](https://github.com/ClickHouse/ClickHouse/pull/10427) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Prefer `fallback_to_stale_replicas` over `skip_unavailable_shards`. [#10422](https://github.com/ClickHouse/ClickHouse/pull/10422) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed wrong flattening of `Array(Tuple(...))` data types. This fixes [#10259](https://github.com/ClickHouse/ClickHouse/issues/10259). [#10390](https://github.com/ClickHouse/ClickHouse/pull/10390) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed wrong behavior in `HashTable` that caused compilation error when trying to read HashMap from buffer. [#10386](https://github.com/ClickHouse/ClickHouse/pull/10386) ([palasonic1](https://github.com/palasonic1)).
+* Fixed possible `Pipeline stuck` error in `ConcatProcessor` which could have happened in remote query. [#10381](https://github.com/ClickHouse/ClickHouse/pull/10381) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed error `Pipeline stuck` with `max_rows_to_group_by` and `group_by_overflow_mode = 'break'`. [#10279](https://github.com/ClickHouse/ClickHouse/pull/10279) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed several bugs when some data was inserted with quorum, then deleted somehow (DROP PARTITION, TTL) and this leaded to the stuck of INSERTs or false-positive exceptions in SELECTs. This fixes [#9946](https://github.com/ClickHouse/ClickHouse/issues/9946). [#10188](https://github.com/ClickHouse/ClickHouse/pull/10188) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed incompatibility when versions prior to 18.12.17 are used on remote servers and newer is used on initiating server, and GROUP BY both fixed and non-fixed keys, and when two-level group by method is activated. [#3254](https://github.com/ClickHouse/ClickHouse/pull/3254) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### Build/Testing/Packaging Improvement
+
+* Added CA certificates to clickhouse-server docker image. [#10476](https://github.com/ClickHouse/ClickHouse/pull/10476) ([filimonov](https://github.com/filimonov)).
+
+
+### ClickHouse release v20.1.10.70, 2020-04-17
+
+#### Bug Fix
+
+* Fix rare possible exception `Cannot drain connections: cancel first`. [#10239](https://github.com/ClickHouse/ClickHouse/pull/10239) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed bug where ClickHouse would throw `'Unknown function lambda.'` error message when user tries to run `ALTER UPDATE/DELETE` on tables with `ENGINE = Replicated*`. Check for nondeterministic functions now handles lambda expressions correctly. [#10237](https://github.com/ClickHouse/ClickHouse/pull/10237) ([Alexander Kazakov](https://github.com/Akazz)).
+* Fix `parseDateTimeBestEffort` for strings in RFC-2822 when day of week is Tuesday or Thursday. This fixes [#10082](https://github.com/ClickHouse/ClickHouse/issues/10082). [#10214](https://github.com/ClickHouse/ClickHouse/pull/10214) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix column names of constants inside `JOIN` that may clash with names of constants outside of `JOIN`. [#10207](https://github.com/ClickHouse/ClickHouse/pull/10207) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible inifinite query execution when the query actually should stop on LIMIT, while reading from infinite source like `system.numbers` or `system.zeros`. [#10206](https://github.com/ClickHouse/ClickHouse/pull/10206) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix move-to-prewhere optimization in presense of `arrayJoin` functions (in certain cases). This fixes [#10092](https://github.com/ClickHouse/ClickHouse/issues/10092). [#10195](https://github.com/ClickHouse/ClickHouse/pull/10195) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add the ability to relax the restriction on non-deterministic functions usage in mutations with `allow_nondeterministic_mutations` setting. [#10186](https://github.com/ClickHouse/ClickHouse/pull/10186) ([filimonov](https://github.com/filimonov)).
+* Convert blocks if structure does not match on `INSERT` into table with `Distributed` engine. [#10135](https://github.com/ClickHouse/ClickHouse/pull/10135) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `SIGSEGV` on `INSERT` into `Distributed` table when its structure differs from the underlying tables. [#10105](https://github.com/ClickHouse/ClickHouse/pull/10105) ([Azat Khuzhin](https://github.com/azat)).
+* Fix possible rows loss for queries with `JOIN` and `UNION ALL`. Fixes [#9826](https://github.com/ClickHouse/ClickHouse/issues/9826), [#10113](https://github.com/ClickHouse/ClickHouse/issues/10113). [#10099](https://github.com/ClickHouse/ClickHouse/pull/10099) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Add arguments check and support identifier arguments for MySQL Database Engine. [#10077](https://github.com/ClickHouse/ClickHouse/pull/10077) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix bug in clickhouse dictionary source from localhost clickhouse server. The bug may lead to memory corruption if types in dictionary and source are not compatible. [#10071](https://github.com/ClickHouse/ClickHouse/pull/10071) ([alesapin](https://github.com/alesapin)).
+* Fix error `Cannot clone block with columns because block has 0 columns ... While executing GroupingAggregatedTransform`. It happened when setting `distributed_aggregation_memory_efficient` was enabled, and distributed query read aggregating data with different level from different shards (mixed single and two level aggregation). [#10063](https://github.com/ClickHouse/ClickHouse/pull/10063) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix a segmentation fault that could occur in `GROUP BY` over string keys containing trailing zero bytes ([#8636](https://github.com/ClickHouse/ClickHouse/issues/8636), [#8925](https://github.com/ClickHouse/ClickHouse/issues/8925)). [#10025](https://github.com/ClickHouse/ClickHouse/pull/10025) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fix bug in which the necessary tables weren't retrieved at one of the processing stages of queries to some databases. Fixes [#9699](https://github.com/ClickHouse/ClickHouse/issues/9699). [#9949](https://github.com/ClickHouse/ClickHouse/pull/9949) ([achulkov2](https://github.com/achulkov2)).
+* Fix `'Not found column in block'` error when `JOIN` appears with `TOTALS`. Fixes [#9839](https://github.com/ClickHouse/ClickHouse/issues/9839). [#9939](https://github.com/ClickHouse/ClickHouse/pull/9939) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix a bug with `ON CLUSTER` DDL queries freezing on server startup. [#9927](https://github.com/ClickHouse/ClickHouse/pull/9927) ([Gagan Arneja](https://github.com/garneja)).
+* Fix `TRUNCATE` for Join table engine ([#9917](https://github.com/ClickHouse/ClickHouse/issues/9917)). [#9920](https://github.com/ClickHouse/ClickHouse/pull/9920) ([Amos Bird](https://github.com/amosbird)).
+* Fix `'scalar does not exist'` error in ALTER queries ([#9878](https://github.com/ClickHouse/ClickHouse/issues/9878)). [#9904](https://github.com/ClickHouse/ClickHouse/pull/9904) ([Amos Bird](https://github.com/amosbird)).
+* Fix race condition between drop and optimize in `ReplicatedMergeTree`. [#9901](https://github.com/ClickHouse/ClickHouse/pull/9901) ([alesapin](https://github.com/alesapin)).
+* Fixed `DeleteOnDestroy` logic in `ATTACH PART` which could lead to automatic removal of attached part and added few tests. [#9410](https://github.com/ClickHouse/ClickHouse/pull/9410) ([Vladimir Chebotarev](https://github.com/excitoon)).
+
+#### Build/Testing/Packaging Improvement
+
+* Fix unit test `collapsing_sorted_stream`. [#9367](https://github.com/ClickHouse/ClickHouse/pull/9367) ([Deleted user](https://github.com/ghost)).
+
+### ClickHouse release v20.1.9.54, 2020-03-28
+
+#### Bug Fix
+
+* Fix `'Different expressions with the same alias'` error when query has `PREWHERE` and `WHERE` on distributed table and `SET distributed_product_mode = 'local'`. [#9871](https://github.com/ClickHouse/ClickHouse/pull/9871) ([Artem Zuikov](https://github.com/4ertus2)).
+* Fix mutations excessive memory consumption for tables with a composite primary key. This fixes [#9850](https://github.com/ClickHouse/ClickHouse/issues/9850). [#9860](https://github.com/ClickHouse/ClickHouse/pull/9860) ([alesapin](https://github.com/alesapin)).
+* For INSERT queries shard now clamps the settings got from the initiator to the shard's constaints instead of throwing an exception. This fix allows to send `INSERT` queries to a shard with another constraints. This change improves fix [#9447](https://github.com/ClickHouse/ClickHouse/issues/9447). [#9852](https://github.com/ClickHouse/ClickHouse/pull/9852) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix possible exception `Got 0 in totals chunk, expected 1` on client. It happened for queries with `JOIN` in case if right joined table had zero rows. Example: `select * from system.one t1 join system.one t2 on t1.dummy = t2.dummy limit 0 FORMAT TabSeparated;`. Fixes [#9777](https://github.com/ClickHouse/ClickHouse/issues/9777). [#9823](https://github.com/ClickHouse/ClickHouse/pull/9823) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix `SIGSEGV` with `optimize_skip_unused_shards` when type cannot be converted. [#9804](https://github.com/ClickHouse/ClickHouse/pull/9804) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed a few cases when timezone of the function argument wasn't used properly. [#9574](https://github.com/ClickHouse/ClickHouse/pull/9574) ([Vasily Nemkov](https://github.com/Enmk)).
+
+#### Improvement
+
+* Remove `ORDER BY` stage from mutations because we read from a single ordered part in a single thread. Also add check that the order of rows in mutation is ordered in sorting key order and this order is not violated. [#9886](https://github.com/ClickHouse/ClickHouse/pull/9886) ([alesapin](https://github.com/alesapin)).
+
+#### Build/Testing/Packaging Improvement
+
+* Clean up duplicated linker flags. Make sure the linker won't look up an unexpected symbol. [#9433](https://github.com/ClickHouse/ClickHouse/pull/9433) ([Amos Bird](https://github.com/amosbird)).
+
+### ClickHouse release v20.1.8.41, 2020-03-20
+
+#### Bug Fix
+* Fix possible permanent `Cannot schedule a task` error (due to unhandled exception in `ParallelAggregatingBlockInputStream::Handler::onFinish/onFinishThread`). This fixes [#6833](https://github.com/ClickHouse/ClickHouse/issues/6833). [#9154](https://github.com/ClickHouse/ClickHouse/pull/9154) ([Azat Khuzhin](https://github.com/azat))
+* Fix excessive memory consumption in `ALTER` queries (mutations). This fixes [#9533](https://github.com/ClickHouse/ClickHouse/issues/9533) and [#9670](https://github.com/ClickHouse/ClickHouse/issues/9670). [#9754](https://github.com/ClickHouse/ClickHouse/pull/9754) ([alesapin](https://github.com/alesapin))
+* Fix bug in backquoting in external dictionaries DDL. This fixes [#9619](https://github.com/ClickHouse/ClickHouse/issues/9619). [#9734](https://github.com/ClickHouse/ClickHouse/pull/9734) ([alesapin](https://github.com/alesapin))
+
+### ClickHouse release v20.1.7.38, 2020-03-18
+
+#### Bug Fix
+* Fixed incorrect internal function names for `sumKahan` and `sumWithOverflow`. I lead to exception while using this functions in remote queries. [#9636](https://github.com/ClickHouse/ClickHouse/pull/9636) ([Azat Khuzhin](https://github.com/azat)). This issue was in all ClickHouse releases.
+* Allow `ALTER ON CLUSTER` of `Distributed` tables with internal replication. This fixes [#3268](https://github.com/ClickHouse/ClickHouse/issues/3268). [#9617](https://github.com/ClickHouse/ClickHouse/pull/9617) ([shinoi2](https://github.com/shinoi2)). This issue was in all ClickHouse releases.
+* Fix possible exceptions `Size of filter does not match size of column` and `Invalid number of rows in Chunk` in `MergeTreeRangeReader`. They could appear while executing `PREWHERE` in some cases. Fixes [#9132](https://github.com/ClickHouse/ClickHouse/issues/9132). [#9612](https://github.com/ClickHouse/ClickHouse/pull/9612) ([Anton Popov](https://github.com/CurtizJ))
+* Fixed the issue: timezone was not preserved if you write a simple arithmetic expression like `time + 1` (in contrast to an expression like `time + INTERVAL 1 SECOND`). This fixes [#5743](https://github.com/ClickHouse/ClickHouse/issues/5743). [#9323](https://github.com/ClickHouse/ClickHouse/pull/9323) ([alexey-milovidov](https://github.com/alexey-milovidov)). This issue was in all ClickHouse releases.
+* Now it's not possible to create or add columns with simple cyclic aliases like `a DEFAULT b, b DEFAULT a`. [#9603](https://github.com/ClickHouse/ClickHouse/pull/9603) ([alesapin](https://github.com/alesapin))
+* Fixed the issue when padding at the end of base64 encoded value can be malformed. Update base64 library. This fixes [#9491](https://github.com/ClickHouse/ClickHouse/issues/9491), closes [#9492](https://github.com/ClickHouse/ClickHouse/issues/9492) [#9500](https://github.com/ClickHouse/ClickHouse/pull/9500) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix data race at destruction of `Poco::HTTPServer`. It could happen when server is started and immediately shut down. [#9468](https://github.com/ClickHouse/ClickHouse/pull/9468) ([Anton Popov](https://github.com/CurtizJ))
+* Fix possible crash/wrong number of rows in `LIMIT n WITH TIES` when there are a lot of rows equal to n'th row. [#9464](https://github.com/ClickHouse/ClickHouse/pull/9464) ([tavplubix](https://github.com/tavplubix))
+* Fix possible mismatched checksums with column TTLs. [#9451](https://github.com/ClickHouse/ClickHouse/pull/9451) ([Anton Popov](https://github.com/CurtizJ))
+* Fix crash when a user tries to `ALTER MODIFY SETTING` for old-formated `MergeTree` table engines family. [#9435](https://github.com/ClickHouse/ClickHouse/pull/9435) ([alesapin](https://github.com/alesapin))
+* Now we will try finalize mutations more frequently. [#9427](https://github.com/ClickHouse/ClickHouse/pull/9427) ([alesapin](https://github.com/alesapin))
+* Fix replication protocol incompatibility introduced in [#8598](https://github.com/ClickHouse/ClickHouse/issues/8598). [#9412](https://github.com/ClickHouse/ClickHouse/pull/9412) ([alesapin](https://github.com/alesapin))
+* Fix not(has()) for the bloom_filter index of array types. [#9407](https://github.com/ClickHouse/ClickHouse/pull/9407) ([achimbab](https://github.com/achimbab))
+* Fixed the behaviour of `match` and `extract` functions when haystack has zero bytes. The behaviour was wrong when haystack was constant. This fixes [#9160](https://github.com/ClickHouse/ClickHouse/issues/9160) [#9163](https://github.com/ClickHouse/ClickHouse/pull/9163) ([alexey-milovidov](https://github.com/alexey-milovidov)) [#9345](https://github.com/ClickHouse/ClickHouse/pull/9345) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Build/Testing/Packaging Improvement
+
+* Exception handling now works correctly on Windows Subsystem for Linux. See https://github.com/ClickHouse-Extras/libunwind/pull/3 This fixes [#6480](https://github.com/ClickHouse/ClickHouse/issues/6480) [#9564](https://github.com/ClickHouse/ClickHouse/pull/9564) ([sobolevsv](https://github.com/sobolevsv))
+
+
+### ClickHouse release v20.1.6.30, 2020-03-05
+
+#### Bug Fix
+
+* Fix data incompatibility when compressed with `T64` codec.
+[#9039](https://github.com/ClickHouse/ClickHouse/pull/9039) [(abyss7)](https://github.com/abyss7)
+* Fix order of ranges while reading from MergeTree table in one thread. Fixes [#8964](https://github.com/ClickHouse/ClickHouse/issues/8964).
+[#9050](https://github.com/ClickHouse/ClickHouse/pull/9050) [(CurtizJ)](https://github.com/CurtizJ)
+* Fix possible segfault in `MergeTreeRangeReader`, while executing `PREWHERE`. Fixes [#9064](https://github.com/ClickHouse/ClickHouse/issues/9064).
+[#9106](https://github.com/ClickHouse/ClickHouse/pull/9106) [(CurtizJ)](https://github.com/CurtizJ)
+* Fix `reinterpretAsFixedString` to return `FixedString` instead of `String`.
+[#9052](https://github.com/ClickHouse/ClickHouse/pull/9052) [(oandrew)](https://github.com/oandrew)
+* Fix `joinGet` with nullable return types. Fixes [#8919](https://github.com/ClickHouse/ClickHouse/issues/8919)
+[#9014](https://github.com/ClickHouse/ClickHouse/pull/9014) [(amosbird)](https://github.com/amosbird)
+* Fix fuzz test and incorrect behaviour of bitTestAll/bitTestAny functions.
+[#9143](https://github.com/ClickHouse/ClickHouse/pull/9143) [(alexey-milovidov)](https://github.com/alexey-milovidov)
+* Fix the behaviour of match and extract functions when haystack has zero bytes. The behaviour was wrong when haystack was constant. Fixes [#9160](https://github.com/ClickHouse/ClickHouse/issues/9160)
+[#9163](https://github.com/ClickHouse/ClickHouse/pull/9163) [(alexey-milovidov)](https://github.com/alexey-milovidov)
+* Fixed execution of inversed predicates when non-strictly monotinic functional index is used. Fixes [#9034](https://github.com/ClickHouse/ClickHouse/issues/9034)
+[#9223](https://github.com/ClickHouse/ClickHouse/pull/9223) [(Akazz)](https://github.com/Akazz)
+* Allow to rewrite `CROSS` to `INNER JOIN` if there's `[NOT] LIKE` operator in `WHERE` section. Fixes [#9191](https://github.com/ClickHouse/ClickHouse/issues/9191)
+[#9229](https://github.com/ClickHouse/ClickHouse/pull/9229) [(4ertus2)](https://github.com/4ertus2)
+* Allow first column(s) in a table with Log engine be an alias.
+[#9231](https://github.com/ClickHouse/ClickHouse/pull/9231) [(abyss7)](https://github.com/abyss7)
+* Allow comma join with `IN()` inside. Fixes [#7314](https://github.com/ClickHouse/ClickHouse/issues/7314).
+[#9251](https://github.com/ClickHouse/ClickHouse/pull/9251) [(4ertus2)](https://github.com/4ertus2)
+* Improve `ALTER MODIFY/ADD` queries logic. Now you cannot `ADD` column without type, `MODIFY` default expression does not change type of column and `MODIFY` type does not loose default expression value. Fixes [#8669](https://github.com/ClickHouse/ClickHouse/issues/8669).
+[#9227](https://github.com/ClickHouse/ClickHouse/pull/9227)  [(alesapin)](https://github.com/alesapin)
+* Fix mutations finalization, when already done mutation can have status is_done=0.
+[#9217](https://github.com/ClickHouse/ClickHouse/pull/9217) [(alesapin)](https://github.com/alesapin)
+* Support "Processors" pipeline for system.numbers and system.numbers_mt. This also fixes the bug when `max_execution_time` is not respected.
+[#7796](https://github.com/ClickHouse/ClickHouse/pull/7796)  [(KochetovNicolai)](https://github.com/KochetovNicolai)
+* Fix wrong counting of `DictCacheKeysRequestedFound` metric.
+[#9411](https://github.com/ClickHouse/ClickHouse/pull/9411) [(nikitamikhaylov)](https://github.com/nikitamikhaylov)
+* Added a check for storage policy in `ATTACH PARTITION FROM`, `REPLACE PARTITION`, `MOVE TO TABLE` which otherwise could make data of part inaccessible after restart and prevent ClickHouse to start.
+[#9383](https://github.com/ClickHouse/ClickHouse/pull/9383) [(excitoon)](https://github.com/excitoon)
+* Fixed UBSan report in `MergeTreeIndexSet`. This fixes [#9250](https://github.com/ClickHouse/ClickHouse/issues/9250)
+[#9365](https://github.com/ClickHouse/ClickHouse/pull/9365) [(alexey-milovidov)](https://github.com/alexey-milovidov)
+* Fix possible datarace in BlockIO.
+[#9356](https://github.com/ClickHouse/ClickHouse/pull/9356) [(KochetovNicolai)](https://github.com/KochetovNicolai)
+* Support for `UInt64` numbers that don't fit in Int64 in JSON-related functions. Update `SIMDJSON` to master. This fixes [#9209](https://github.com/ClickHouse/ClickHouse/issues/9209)
+[#9344](https://github.com/ClickHouse/ClickHouse/pull/9344) [(alexey-milovidov)](https://github.com/alexey-milovidov)
+* Fix the issue when the amount of free space is not calculated correctly if the data directory is mounted to a separate device. For default disk calculate the free space from data subdirectory. This fixes [#7441](https://github.com/ClickHouse/ClickHouse/issues/7441)
+[#9257](https://github.com/ClickHouse/ClickHouse/pull/9257) [(millb)](https://github.com/millb)
+* Fix the issue when TLS connections may fail with the message `OpenSSL SSL_read: error:14094438:SSL routines:ssl3_read_bytes:tlsv1 alert internal error and SSL Exception: error:2400006E:random number generator::error retrieving entropy.` Update OpenSSL to upstream master.
+[#8956](https://github.com/ClickHouse/ClickHouse/pull/8956) [(alexey-milovidov)](https://github.com/alexey-milovidov)
+* When executing `CREATE` query, fold constant expressions in storage engine arguments. Replace empty database name with current database. Fixes [#6508](https://github.com/ClickHouse/ClickHouse/issues/6508), [#3492](https://github.com/ClickHouse/ClickHouse/issues/3492). Also fix check for local address in ClickHouseDictionarySource.
+[#9262](https://github.com/ClickHouse/ClickHouse/pull/9262) [(tabplubix)](https://github.com/tavplubix)
+* Fix segfault in `StorageMerge`, which can happen when reading from StorageFile.
+[#9387](https://github.com/ClickHouse/ClickHouse/pull/9387) [(tabplubix)](https://github.com/tavplubix)
+* Prevent losing data in `Kafka` in rare cases when exception happens after reading suffix but before commit. Fixes [#9378](https://github.com/ClickHouse/ClickHouse/issues/9378). Related: [#7175](https://github.com/ClickHouse/ClickHouse/issues/7175)
+[#9507](https://github.com/ClickHouse/ClickHouse/pull/9507) [(filimonov)](https://github.com/filimonov)
+* Fix bug leading to server termination when trying to use / drop `Kafka` table created with wrong parameters. Fixes [#9494](https://github.com/ClickHouse/ClickHouse/issues/9494). Incorporates [#9507](https://github.com/ClickHouse/ClickHouse/issues/9507).
+[#9513](https://github.com/ClickHouse/ClickHouse/pull/9513) [(filimonov)](https://github.com/filimonov)
+
+#### New Feature
+* Add `deduplicate_blocks_in_dependent_materialized_views` option to control the behaviour of idempotent inserts into tables with materialized views. This new feature was added to the bugfix release by a special request from Altinity.
+[#9070](https://github.com/ClickHouse/ClickHouse/pull/9070) [(urykhy)](https://github.com/urykhy)
+
+### ClickHouse release v20.1.2.4, 2020-01-22
+
+#### Backward Incompatible Change
+* Make the setting `merge_tree_uniform_read_distribution` obsolete. The server still recognizes this setting but it has no effect. [#8308](https://github.com/ClickHouse/ClickHouse/pull/8308) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Changed return type of the function `greatCircleDistance` to `Float32` because now the result of calculation is `Float32`. [#7993](https://github.com/ClickHouse/ClickHouse/pull/7993) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Now it's expected that query parameters are represented in "escaped" format. For example, to pass string `a<tab>b` you have to write `a\tb` or `a\<tab>b` and respectively, `a%5Ctb` or `a%5C%09b` in URL. This is needed to add the possibility to pass NULL as `\N`. This fixes [#7488](https://github.com/ClickHouse/ClickHouse/issues/7488). [#8517](https://github.com/ClickHouse/ClickHouse/pull/8517) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Enable `use_minimalistic_part_header_in_zookeeper` setting for `ReplicatedMergeTree` by default. This will significantly reduce amount of data stored in ZooKeeper. This setting is supported since version 19.1 and we already use it in production in multiple services without any issues for more than half a year. Disable this setting if you have a chance to downgrade to versions older than 19.1. [#6850](https://github.com/ClickHouse/ClickHouse/pull/6850) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Data skipping indices are production ready and enabled by default. The settings `allow_experimental_data_skipping_indices`, `allow_experimental_cross_to_join_conversion` and `allow_experimental_multiple_joins_emulation` are now obsolete and do nothing. [#7974](https://github.com/ClickHouse/ClickHouse/pull/7974) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add new `ANY JOIN` logic for `StorageJoin` consistent with `JOIN` operation. To upgrade without changes in behaviour you need add `SETTINGS any_join_distinct_right_table_keys = 1` to Engine Join tables metadata or recreate these tables after upgrade. [#8400](https://github.com/ClickHouse/ClickHouse/pull/8400) ([Artem Zuikov](https://github.com/4ertus2))
+* Require server to be restarted to apply the changes in logging configuration. This is a temporary workaround to avoid the bug where the server logs to a deleted log file (see [#8696](https://github.com/ClickHouse/ClickHouse/issues/8696)). [#8707](https://github.com/ClickHouse/ClickHouse/pull/8707) ([Alexander Kuzmenkov](https://github.com/akuzm))
+
+#### New Feature
+* Added information about part paths to `system.merges`. [#8043](https://github.com/ClickHouse/ClickHouse/pull/8043) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Add ability to execute `SYSTEM RELOAD DICTIONARY` query in `ON CLUSTER` mode. [#8288](https://github.com/ClickHouse/ClickHouse/pull/8288) ([Guillaume Tassery](https://github.com/YiuRULE))
+* Add ability to execute `CREATE DICTIONARY` queries in `ON CLUSTER` mode. [#8163](https://github.com/ClickHouse/ClickHouse/pull/8163) ([alesapin](https://github.com/alesapin))
+* Now user's profile in `users.xml` can inherit multiple profiles. [#8343](https://github.com/ClickHouse/ClickHouse/pull/8343) ([Mikhail f. Shiryaev](https://github.com/Felixoid))
+* Added `system.stack_trace` table that allows to look at stack traces of all server threads. This is useful for developers to introspect server state. This fixes [#7576](https://github.com/ClickHouse/ClickHouse/issues/7576). [#8344](https://github.com/ClickHouse/ClickHouse/pull/8344) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add `DateTime64` datatype with configurable sub-second precision. [#7170](https://github.com/ClickHouse/ClickHouse/pull/7170) ([Vasily Nemkov](https://github.com/Enmk))
+* Add table function `clusterAllReplicas` which allows to query all the nodes in the cluster. [#8493](https://github.com/ClickHouse/ClickHouse/pull/8493) ([kiran sunkari](https://github.com/kiransunkari))
+* Add aggregate function `categoricalInformationValue` which calculates the information value of a discrete feature. [#8117](https://github.com/ClickHouse/ClickHouse/pull/8117) ([hcz](https://github.com/hczhcz))
+* Speed up parsing of data files in `CSV`, `TSV` and `JSONEachRow` format by doing it in parallel. [#7780](https://github.com/ClickHouse/ClickHouse/pull/7780) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Add function `bankerRound` which performs banker's rounding. [#8112](https://github.com/ClickHouse/ClickHouse/pull/8112) ([hcz](https://github.com/hczhcz))
+* Support more languages in embedded dictionary for region names: 'ru', 'en', 'ua', 'uk', 'by', 'kz', 'tr', 'de', 'uz', 'lv', 'lt', 'et', 'pt', 'he', 'vi'. [#8189](https://github.com/ClickHouse/ClickHouse/pull/8189) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Improvements in consistency of `ANY JOIN` logic. Now `t1 ANY LEFT JOIN t2` equals `t2 ANY RIGHT JOIN t1`. [#7665](https://github.com/ClickHouse/ClickHouse/pull/7665) ([Artem Zuikov](https://github.com/4ertus2))
+* Add setting `any_join_distinct_right_table_keys` which enables old behaviour for `ANY INNER JOIN`. [#7665](https://github.com/ClickHouse/ClickHouse/pull/7665) ([Artem Zuikov](https://github.com/4ertus2))
+* Add new `SEMI` and `ANTI JOIN`. Old `ANY INNER JOIN` behaviour now available as `SEMI LEFT JOIN`. [#7665](https://github.com/ClickHouse/ClickHouse/pull/7665) ([Artem Zuikov](https://github.com/4ertus2))
+* Added `Distributed` format for `File` engine and `file` table function which allows to read from `.bin` files generated by asynchronous  inserts into `Distributed` table. [#8535](https://github.com/ClickHouse/ClickHouse/pull/8535) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Add optional reset column argument for `runningAccumulate` which allows to reset aggregation results for each new key value. [#8326](https://github.com/ClickHouse/ClickHouse/pull/8326) ([Sergey Kononenko](https://github.com/kononencheg))
+* Add ability to use ClickHouse as Prometheus endpoint. [#7900](https://github.com/ClickHouse/ClickHouse/pull/7900) ([vdimir](https://github.com/Vdimir))
+* Add section `<remote_url_allow_hosts>` in `config.xml` which restricts allowed hosts for remote table engines and table functions `URL`, `S3`, `HDFS`. [#7154](https://github.com/ClickHouse/ClickHouse/pull/7154) ([Mikhail Korotov](https://github.com/millb))
+* Added function `greatCircleAngle` which calculates the distance on a sphere in degrees. [#8105](https://github.com/ClickHouse/ClickHouse/pull/8105) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Changed Earth radius to be consistent with H3 library. [#8105](https://github.com/ClickHouse/ClickHouse/pull/8105) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added `JSONCompactEachRow` and `JSONCompactEachRowWithNamesAndTypes` formats for input and output. [#7841](https://github.com/ClickHouse/ClickHouse/pull/7841) ([Mikhail Korotov](https://github.com/millb))
+* Added feature for file-related table engines and table functions (`File`, `S3`, `URL`, `HDFS`) which allows to read and write `gzip` files based on additional engine parameter or file extension. [#7840](https://github.com/ClickHouse/ClickHouse/pull/7840) ([Andrey Bodrov](https://github.com/apbodrov))
+* Added the `randomASCII(length)` function, generating a string with a random set of [ASCII](https://en.wikipedia.org/wiki/ASCII#Printable_characters) printable characters. [#8401](https://github.com/ClickHouse/ClickHouse/pull/8401) ([BayoNet](https://github.com/BayoNet))
+* Added function `JSONExtractArrayRaw` which returns an array on unparsed json array elements from `JSON` string. [#8081](https://github.com/ClickHouse/ClickHouse/pull/8081) ([Oleg Matrokhin](https://github.com/errx))
+* Add `arrayZip` function which allows to combine multiple arrays of equal lengths into one array of tuples. [#8149](https://github.com/ClickHouse/ClickHouse/pull/8149) ([Winter Zhang](https://github.com/zhang2014))
+* Add ability to move data between disks according to configured `TTL`-expressions for `*MergeTree` table engines family. [#8140](https://github.com/ClickHouse/ClickHouse/pull/8140) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Added new aggregate function `avgWeighted` which allows to calculate weighted average. [#7898](https://github.com/ClickHouse/ClickHouse/pull/7898) ([Andrey Bodrov](https://github.com/apbodrov))
+* Now parallel parsing is enabled by default for `TSV`, `TSKV`, `CSV` and `JSONEachRow` formats. [#7894](https://github.com/ClickHouse/ClickHouse/pull/7894) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Add several geo functions from `H3` library: `h3GetResolution`, `h3EdgeAngle`, `h3EdgeLength`, `h3IsValid` and `h3kRing`. [#8034](https://github.com/ClickHouse/ClickHouse/pull/8034) ([Konstantin Malanchev](https://github.com/hombit))
+* Added support for brotli (`br`) compression in file-related storages and table functions. This fixes [#8156](https://github.com/ClickHouse/ClickHouse/issues/8156). [#8526](https://github.com/ClickHouse/ClickHouse/pull/8526) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add `groupBit*` functions for the `SimpleAggregationFunction` type. [#8485](https://github.com/ClickHouse/ClickHouse/pull/8485) ([Guillaume Tassery](https://github.com/YiuRULE))
+
+#### Bug Fix
+* Fix rename of tables with `Distributed` engine. Fixes issue [#7868](https://github.com/ClickHouse/ClickHouse/issues/7868). [#8306](https://github.com/ClickHouse/ClickHouse/pull/8306) ([tavplubix](https://github.com/tavplubix))
+* Now dictionaries support `EXPRESSION` for attributes in arbitrary string in non-ClickHouse SQL dialect. [#8098](https://github.com/ClickHouse/ClickHouse/pull/8098) ([alesapin](https://github.com/alesapin))
+* Fix broken `INSERT SELECT FROM mysql(...)` query. This fixes [#8070](https://github.com/ClickHouse/ClickHouse/issues/8070) and [#7960](https://github.com/ClickHouse/ClickHouse/issues/7960). [#8234](https://github.com/ClickHouse/ClickHouse/pull/8234) ([tavplubix](https://github.com/tavplubix))
+* Fix error "Mismatch column sizes" when inserting default `Tuple` from `JSONEachRow`. This fixes [#5653](https://github.com/ClickHouse/ClickHouse/issues/5653). [#8606](https://github.com/ClickHouse/ClickHouse/pull/8606) ([tavplubix](https://github.com/tavplubix))
+* Now an exception will be thrown in case of using `WITH TIES` alongside `LIMIT BY`. Also add ability to use `TOP` with `LIMIT BY`. This fixes [#7472](https://github.com/ClickHouse/ClickHouse/issues/7472). [#7637](https://github.com/ClickHouse/ClickHouse/pull/7637) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Fix unintendent dependency from fresh glibc version in `clickhouse-odbc-bridge` binary. [#8046](https://github.com/ClickHouse/ClickHouse/pull/8046) ([Amos Bird](https://github.com/amosbird))
+* Fix bug in check function of `*MergeTree` engines family. Now it does not fail in case when we have equal amount of rows in last granule and last mark (non-final). [#8047](https://github.com/ClickHouse/ClickHouse/pull/8047) ([alesapin](https://github.com/alesapin))
+* Fix insert into `Enum*` columns after `ALTER` query, when underlying numeric type is equal to table specified type. This fixes [#7836](https://github.com/ClickHouse/ClickHouse/issues/7836). [#7908](https://github.com/ClickHouse/ClickHouse/pull/7908) ([Anton Popov](https://github.com/CurtizJ))
+* Allowed non-constant negative "size" argument for function `substring`. It was not allowed by mistake. This fixes [#4832](https://github.com/ClickHouse/ClickHouse/issues/4832). [#7703](https://github.com/ClickHouse/ClickHouse/pull/7703) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix parsing bug when wrong number of arguments passed to `(O|J)DBC` table engine. [#7709](https://github.com/ClickHouse/ClickHouse/pull/7709) ([alesapin](https://github.com/alesapin))
+* Using command name of the running clickhouse process when sending logs to syslog. In previous versions, empty string was used instead of command name. [#8460](https://github.com/ClickHouse/ClickHouse/pull/8460) ([Michael Nacharov](https://github.com/mnach))
+* Fix check of allowed hosts for `localhost`. This PR fixes the solution provided in [#8241](https://github.com/ClickHouse/ClickHouse/pull/8241). [#8342](https://github.com/ClickHouse/ClickHouse/pull/8342) ([Vitaly Baranov](https://github.com/vitlibar))
+* Fix rare crash in `argMin` and `argMax` functions for long string arguments, when result is used in `runningAccumulate` function. This fixes [#8325](https://github.com/ClickHouse/ClickHouse/issues/8325) [#8341](https://github.com/ClickHouse/ClickHouse/pull/8341) ([dinosaur](https://github.com/769344359))
+* Fix memory overcommit for tables with `Buffer` engine. [#8345](https://github.com/ClickHouse/ClickHouse/pull/8345) ([Azat Khuzhin](https://github.com/azat))
+* Fixed potential bug in functions that can take `NULL` as one of the arguments and return non-NULL. [#8196](https://github.com/ClickHouse/ClickHouse/pull/8196) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Better metrics calculations in thread pool for background processes for `MergeTree` table engines. [#8194](https://github.com/ClickHouse/ClickHouse/pull/8194) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix function `IN` inside `WHERE` statement when row-level table filter is present. Fixes [#6687](https://github.com/ClickHouse/ClickHouse/issues/6687) [#8357](https://github.com/ClickHouse/ClickHouse/pull/8357) ([Ivan](https://github.com/abyss7))
+* Now an exception is thrown if the integral value is not parsed completely for settings values. [#7678](https://github.com/ClickHouse/ClickHouse/pull/7678) ([Mikhail Korotov](https://github.com/millb))
+* Fix exception when aggregate function is used in query to distributed table with more than two local shards. [#8164](https://github.com/ClickHouse/ClickHouse/pull/8164) ([小路](https://github.com/nicelulu))
+* Now bloom filter can handle zero length arrays and does not perform redundant calculations. [#8242](https://github.com/ClickHouse/ClickHouse/pull/8242) ([achimbab](https://github.com/achimbab))
+* Fixed checking if a client host is allowed by matching the client host to `host_regexp` specified in `users.xml`. [#8241](https://github.com/ClickHouse/ClickHouse/pull/8241) ([Vitaly Baranov](https://github.com/vitlibar))
+* Relax ambiguous column check that leads to false positives in multiple `JOIN ON` section. [#8385](https://github.com/ClickHouse/ClickHouse/pull/8385) ([Artem Zuikov](https://github.com/4ertus2))
+* Fixed possible server crash (`std::terminate`) when the server cannot send or write data in `JSON` or `XML` format with values of `String` data type (that require `UTF-8` validation) or when compressing result data with Brotli algorithm or in some other rare cases. This fixes [#7603](https://github.com/ClickHouse/ClickHouse/issues/7603) [#8384](https://github.com/ClickHouse/ClickHouse/pull/8384) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix race condition in `StorageDistributedDirectoryMonitor` found by CI. This fixes [#8364](https://github.com/ClickHouse/ClickHouse/issues/8364). [#8383](https://github.com/ClickHouse/ClickHouse/pull/8383) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Now background merges in `*MergeTree` table engines family preserve storage policy volume order more accurately. [#8549](https://github.com/ClickHouse/ClickHouse/pull/8549) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Now table engine `Kafka` works properly with `Native` format. This fixes [#6731](https://github.com/ClickHouse/ClickHouse/issues/6731) [#7337](https://github.com/ClickHouse/ClickHouse/issues/7337) [#8003](https://github.com/ClickHouse/ClickHouse/issues/8003). [#8016](https://github.com/ClickHouse/ClickHouse/pull/8016) ([filimonov](https://github.com/filimonov))
+* Fixed formats with headers (like `CSVWithNames`) which were throwing exception about EOF for table engine `Kafka`. [#8016](https://github.com/ClickHouse/ClickHouse/pull/8016) ([filimonov](https://github.com/filimonov))
+* Fixed a bug with making set from subquery in right part of `IN` section. This fixes [#5767](https://github.com/ClickHouse/ClickHouse/issues/5767) and [#2542](https://github.com/ClickHouse/ClickHouse/issues/2542). [#7755](https://github.com/ClickHouse/ClickHouse/pull/7755) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Fix possible crash while reading from storage `File`. [#7756](https://github.com/ClickHouse/ClickHouse/pull/7756) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fixed reading of the files in `Parquet` format containing columns of type `list`. [#8334](https://github.com/ClickHouse/ClickHouse/pull/8334) ([maxulan](https://github.com/maxulan))
+* Fix error `Not found column` for distributed queries with `PREWHERE` condition dependent on sampling key if `max_parallel_replicas > 1`. [#7913](https://github.com/ClickHouse/ClickHouse/pull/7913) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix error `Not found column` if query used `PREWHERE` dependent on table's alias and the result set was empty because of primary key condition. [#7911](https://github.com/ClickHouse/ClickHouse/pull/7911) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fixed return type for functions `rand` and `randConstant` in case of `Nullable` argument. Now functions always return `UInt32` and never `Nullable(UInt32)`. [#8204](https://github.com/ClickHouse/ClickHouse/pull/8204) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Disabled predicate push-down for `WITH FILL` expression. This fixes [#7784](https://github.com/ClickHouse/ClickHouse/issues/7784). [#7789](https://github.com/ClickHouse/ClickHouse/pull/7789) ([Winter Zhang](https://github.com/zhang2014))
+* Fixed incorrect `count()` result for `SummingMergeTree` when `FINAL` section is used. [#3280](https://github.com/ClickHouse/ClickHouse/issues/3280) [#7786](https://github.com/ClickHouse/ClickHouse/pull/7786) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Fix possible incorrect result for constant functions from remote servers. It happened for queries with functions like `version()`, `uptime()`, etc. which returns different constant values for different servers. This fixes [#7666](https://github.com/ClickHouse/ClickHouse/issues/7666). [#7689](https://github.com/ClickHouse/ClickHouse/pull/7689) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix complicated bug in push-down predicate optimization which leads to wrong results. This fixes a lot of issues on push-down predicate optimization. [#8503](https://github.com/ClickHouse/ClickHouse/pull/8503) ([Winter Zhang](https://github.com/zhang2014))
+* Fix crash in `CREATE TABLE .. AS dictionary` query. [#8508](https://github.com/ClickHouse/ClickHouse/pull/8508) ([Azat Khuzhin](https://github.com/azat))
+* Several improvements ClickHouse grammar in `.g4` file. [#8294](https://github.com/ClickHouse/ClickHouse/pull/8294) ([taiyang-li](https://github.com/taiyang-li))
+* Fix bug that leads to crashes in `JOIN`s with tables with engine `Join`. This fixes [#7556](https://github.com/ClickHouse/ClickHouse/issues/7556) [#8254](https://github.com/ClickHouse/ClickHouse/issues/8254) [#7915](https://github.com/ClickHouse/ClickHouse/issues/7915) [#8100](https://github.com/ClickHouse/ClickHouse/issues/8100). [#8298](https://github.com/ClickHouse/ClickHouse/pull/8298) ([Artem Zuikov](https://github.com/4ertus2))
+* Fix redundant dictionaries reload on `CREATE DATABASE`. [#7916](https://github.com/ClickHouse/ClickHouse/pull/7916) ([Azat Khuzhin](https://github.com/azat))
+* Limit maximum number of streams for read from `StorageFile` and `StorageHDFS`. Fixes [#7650](https://github.com/ClickHouse/ClickHouse/issues/7650). [#7981](https://github.com/ClickHouse/ClickHouse/pull/7981) ([alesapin](https://github.com/alesapin))
+* Fix bug in `ALTER ... MODIFY ... CODEC` query, when user specify both default expression and codec. Fixes [8593](https://github.com/ClickHouse/ClickHouse/issues/8593). [#8614](https://github.com/ClickHouse/ClickHouse/pull/8614) ([alesapin](https://github.com/alesapin))
+* Fix error in background merge of columns with `SimpleAggregateFunction(LowCardinality)` type. [#8613](https://github.com/ClickHouse/ClickHouse/pull/8613) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fixed type check in function `toDateTime64`. [#8375](https://github.com/ClickHouse/ClickHouse/pull/8375) ([Vasily Nemkov](https://github.com/Enmk))
+* Now server do not crash on `LEFT` or `FULL JOIN` with and Join engine and unsupported `join_use_nulls` settings. [#8479](https://github.com/ClickHouse/ClickHouse/pull/8479) ([Artem Zuikov](https://github.com/4ertus2))
+* Now `DROP DICTIONARY IF EXISTS db.dict` query does not throw exception if `db` does not exist. [#8185](https://github.com/ClickHouse/ClickHouse/pull/8185) ([Vitaly Baranov](https://github.com/vitlibar))
+* Fix possible crashes in table functions (`file`, `mysql`, `remote`) caused by usage of reference to removed `IStorage` object. Fix incorrect parsing of columns specified at insertion into table function. [#7762](https://github.com/ClickHouse/ClickHouse/pull/7762) ([tavplubix](https://github.com/tavplubix))
+* Ensure network be up before starting `clickhouse-server`. This fixes [#7507](https://github.com/ClickHouse/ClickHouse/issues/7507). [#8570](https://github.com/ClickHouse/ClickHouse/pull/8570) ([Zhichang Yu](https://github.com/yuzhichang))
+* Fix timeouts handling for secure connections, so queries does not hang indefenitely. This fixes [#8126](https://github.com/ClickHouse/ClickHouse/issues/8126). [#8128](https://github.com/ClickHouse/ClickHouse/pull/8128) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix `clickhouse-copier`'s redundant contention between concurrent workers. [#7816](https://github.com/ClickHouse/ClickHouse/pull/7816) ([Ding Xiang Fei](https://github.com/dingxiangfei2009))
+* Now mutations does not skip attached parts, even if their mutation version were larger than current mutation version. [#7812](https://github.com/ClickHouse/ClickHouse/pull/7812) ([Zhichang Yu](https://github.com/yuzhichang)) [#8250](https://github.com/ClickHouse/ClickHouse/pull/8250) ([alesapin](https://github.com/alesapin))
+* Ignore redundant copies of `*MergeTree` data parts after move to another disk and server restart. [#7810](https://github.com/ClickHouse/ClickHouse/pull/7810) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix crash in `FULL JOIN` with `LowCardinality` in `JOIN` key. [#8252](https://github.com/ClickHouse/ClickHouse/pull/8252) ([Artem Zuikov](https://github.com/4ertus2))
+* Forbidden to use column name more than once in insert query like `INSERT INTO tbl (x, y, x)`. This fixes [#5465](https://github.com/ClickHouse/ClickHouse/issues/5465), [#7681](https://github.com/ClickHouse/ClickHouse/issues/7681). [#7685](https://github.com/ClickHouse/ClickHouse/pull/7685) ([alesapin](https://github.com/alesapin))
+* Added fallback for detection the number of physical CPU cores for unknown CPUs (using the number of logical CPU cores). This fixes [#5239](https://github.com/ClickHouse/ClickHouse/issues/5239). [#7726](https://github.com/ClickHouse/ClickHouse/pull/7726) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix `There's no column` error for materialized and alias columns. [#8210](https://github.com/ClickHouse/ClickHouse/pull/8210) ([Artem Zuikov](https://github.com/4ertus2))
+* Fixed sever crash when `EXISTS` query was used without `TABLE` or `DICTIONARY` qualifier. Just like `EXISTS t`. This fixes [#8172](https://github.com/ClickHouse/ClickHouse/issues/8172). This bug was introduced in version 19.17. [#8213](https://github.com/ClickHouse/ClickHouse/pull/8213) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix rare bug with error `"Sizes of columns does not match"` that might appear when using `SimpleAggregateFunction` column. [#7790](https://github.com/ClickHouse/ClickHouse/pull/7790) ([Boris Granveaud](https://github.com/bgranvea))
+* Fix bug where user with empty `allow_databases` got access to all databases (and same for `allow_dictionaries`). [#7793](https://github.com/ClickHouse/ClickHouse/pull/7793) ([DeifyTheGod](https://github.com/DeifyTheGod))
+* Fix client crash when server already disconnected from client. [#8071](https://github.com/ClickHouse/ClickHouse/pull/8071) ([Azat Khuzhin](https://github.com/azat))
+* Fix `ORDER BY` behaviour in case of sorting by primary key prefix and non primary key suffix. [#7759](https://github.com/ClickHouse/ClickHouse/pull/7759) ([Anton Popov](https://github.com/CurtizJ))
+* Check if qualified column present in the table. This fixes [#6836](https://github.com/ClickHouse/ClickHouse/issues/6836). [#7758](https://github.com/ClickHouse/ClickHouse/pull/7758) ([Artem Zuikov](https://github.com/4ertus2))
+* Fixed behavior with `ALTER MOVE` ran immediately after merge finish moves superpart of specified. Fixes [#8103](https://github.com/ClickHouse/ClickHouse/issues/8103). [#8104](https://github.com/ClickHouse/ClickHouse/pull/8104) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix possible server crash while using `UNION` with different number of columns. Fixes [#7279](https://github.com/ClickHouse/ClickHouse/issues/7279). [#7929](https://github.com/ClickHouse/ClickHouse/pull/7929) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix size of result substring for function `substr` with negative size. [#8589](https://github.com/ClickHouse/ClickHouse/pull/8589) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Now server does not execute part mutation in `MergeTree` if there are not enough free threads in background pool.  [#8588](https://github.com/ClickHouse/ClickHouse/pull/8588) ([tavplubix](https://github.com/tavplubix))
+* Fix a minor typo on formatting `UNION ALL` AST. [#7999](https://github.com/ClickHouse/ClickHouse/pull/7999) ([litao91](https://github.com/litao91))
+* Fixed incorrect bloom filter results for negative numbers. This fixes [#8317](https://github.com/ClickHouse/ClickHouse/issues/8317). [#8566](https://github.com/ClickHouse/ClickHouse/pull/8566) ([Winter Zhang](https://github.com/zhang2014))
+* Fixed potential buffer overflow in decompress. Malicious user can pass fabricated compressed data that will cause read after buffer. This issue was found by Eldar Zaitov from Yandex information security team. [#8404](https://github.com/ClickHouse/ClickHouse/pull/8404) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix incorrect result because of integers overflow in `arrayIntersect`. [#7777](https://github.com/ClickHouse/ClickHouse/pull/7777) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Now `OPTIMIZE TABLE` query will not wait for offline replicas to perform the operation. [#8314](https://github.com/ClickHouse/ClickHouse/pull/8314) ([javi santana](https://github.com/javisantana))
+* Fixed `ALTER TTL` parser for `Replicated*MergeTree` tables. [#8318](https://github.com/ClickHouse/ClickHouse/pull/8318) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix communication between server and client, so server read temporary tables info after query failure. [#8084](https://github.com/ClickHouse/ClickHouse/pull/8084) ([Azat Khuzhin](https://github.com/azat))
+* Fix `bitmapAnd` function error when intersecting an aggregated bitmap and a scalar bitmap. [#8082](https://github.com/ClickHouse/ClickHouse/pull/8082) ([Yue Huang](https://github.com/moon03432))
+* Refine the definition of `ZXid` according to the ZooKeeper Programmer's Guide which fixes bug in `clickhouse-cluster-copier`. [#8088](https://github.com/ClickHouse/ClickHouse/pull/8088) ([Ding Xiang Fei](https://github.com/dingxiangfei2009))
+* `odbc` table function now respects `external_table_functions_use_nulls` setting. [#7506](https://github.com/ClickHouse/ClickHouse/pull/7506) ([Vasily Nemkov](https://github.com/Enmk))
+* Fixed bug that lead to a rare data race. [#8143](https://github.com/ClickHouse/ClickHouse/pull/8143) ([Alexander Kazakov](https://github.com/Akazz))
+* Now `SYSTEM RELOAD DICTIONARY` reloads a dictionary completely, ignoring `update_field`. This fixes [#7440](https://github.com/ClickHouse/ClickHouse/issues/7440). [#8037](https://github.com/ClickHouse/ClickHouse/pull/8037) ([Vitaly Baranov](https://github.com/vitlibar))
+* Add ability to check if dictionary exists in create query. [#8032](https://github.com/ClickHouse/ClickHouse/pull/8032) ([alesapin](https://github.com/alesapin))
+* Fix `Float*` parsing in `Values` format. This fixes [#7817](https://github.com/ClickHouse/ClickHouse/issues/7817). [#7870](https://github.com/ClickHouse/ClickHouse/pull/7870) ([tavplubix](https://github.com/tavplubix))
+* Fix crash when we cannot reserve space in some background operations of `*MergeTree` table engines family. [#7873](https://github.com/ClickHouse/ClickHouse/pull/7873) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix crash of merge operation when table contains `SimpleAggregateFunction(LowCardinality)` column. This fixes [#8515](https://github.com/ClickHouse/ClickHouse/issues/8515). [#8522](https://github.com/ClickHouse/ClickHouse/pull/8522) ([Azat Khuzhin](https://github.com/azat))
+* Restore support of all ICU locales and add the ability to apply collations for constant expressions. Also add language name to `system.collations` table. [#8051](https://github.com/ClickHouse/ClickHouse/pull/8051) ([alesapin](https://github.com/alesapin))
+* Fix bug when external dictionaries with zero minimal lifetime (`LIFETIME(MIN 0 MAX N)`, `LIFETIME(N)`) don't update in background. [#7983](https://github.com/ClickHouse/ClickHouse/pull/7983) ([alesapin](https://github.com/alesapin))
+* Fix crash when external dictionary with ClickHouse source has subquery in query. [#8351](https://github.com/ClickHouse/ClickHouse/pull/8351) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fix incorrect parsing of file extension in table with engine `URL`. This fixes [#8157](https://github.com/ClickHouse/ClickHouse/issues/8157). [#8419](https://github.com/ClickHouse/ClickHouse/pull/8419) ([Andrey Bodrov](https://github.com/apbodrov))
+* Fix `CHECK TABLE` query for `*MergeTree` tables without key. Fixes [#7543](https://github.com/ClickHouse/ClickHouse/issues/7543). [#7979](https://github.com/ClickHouse/ClickHouse/pull/7979) ([alesapin](https://github.com/alesapin))
+* Fixed conversion of `Float64` to MySQL type. [#8079](https://github.com/ClickHouse/ClickHouse/pull/8079) ([Yuriy Baranov](https://github.com/yurriy))
+* Now if table was not completely dropped because of server crash, server will try to restore and load it. [#8176](https://github.com/ClickHouse/ClickHouse/pull/8176) ([tavplubix](https://github.com/tavplubix))
+* Fixed crash in table function `file` while inserting into file that does not exist. Now in this case file would be created and then insert would be processed. [#8177](https://github.com/ClickHouse/ClickHouse/pull/8177) ([Olga Khvostikova](https://github.com/stavrolia))
+* Fix rare deadlock which can happen when `trace_log` is in enabled. [#7838](https://github.com/ClickHouse/ClickHouse/pull/7838) ([filimonov](https://github.com/filimonov))
+* Add ability to work with different types besides `Date` in `RangeHashed` external dictionary created from DDL query. Fixes [7899](https://github.com/ClickHouse/ClickHouse/issues/7899). [#8275](https://github.com/ClickHouse/ClickHouse/pull/8275) ([alesapin](https://github.com/alesapin))
+* Fixes crash when `now64()` is called with result of another function. [#8270](https://github.com/ClickHouse/ClickHouse/pull/8270) ([Vasily Nemkov](https://github.com/Enmk))
+* Fixed bug with detecting client IP for connections through mysql wire protocol. [#7743](https://github.com/ClickHouse/ClickHouse/pull/7743) ([Dmitry Muzyka](https://github.com/dmitriy-myz))
+* Fix empty array handling in `arraySplit` function. This fixes [#7708](https://github.com/ClickHouse/ClickHouse/issues/7708). [#7747](https://github.com/ClickHouse/ClickHouse/pull/7747) ([hcz](https://github.com/hczhcz))
+* Fixed the issue when `pid-file` of another running `clickhouse-server` may be deleted. [#8487](https://github.com/ClickHouse/ClickHouse/pull/8487) ([Weiqing Xu](https://github.com/weiqxu))
+* Fix dictionary reload if it has `invalidate_query`, which stopped updates and some exception on previous update tries. [#8029](https://github.com/ClickHouse/ClickHouse/pull/8029) ([alesapin](https://github.com/alesapin))
+* Fixed error in function `arrayReduce` that may lead to "double free" and error in aggregate function combinator `Resample` that may lead to memory leak. Added aggregate function `aggThrow`. This function can be used for testing purposes. [#8446](https://github.com/ClickHouse/ClickHouse/pull/8446) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Improvement
+* Improved logging when working with `S3` table engine. [#8251](https://github.com/ClickHouse/ClickHouse/pull/8251) ([Grigory Pervakov](https://github.com/GrigoryPervakov))
+* Printed help message when no arguments are passed when calling `clickhouse-local`. This fixes [#5335](https://github.com/ClickHouse/ClickHouse/issues/5335). [#8230](https://github.com/ClickHouse/ClickHouse/pull/8230) ([Andrey Nagorny](https://github.com/Melancholic))
+* Add setting `mutations_sync` which allows to wait `ALTER UPDATE/DELETE` queries synchronously. [#8237](https://github.com/ClickHouse/ClickHouse/pull/8237) ([alesapin](https://github.com/alesapin))
+* Allow to set up relative `user_files_path` in `config.xml` (in the way similar to `format_schema_path`). [#7632](https://github.com/ClickHouse/ClickHouse/pull/7632) ([hcz](https://github.com/hczhcz))
+* Add exception for illegal types for conversion functions with `-OrZero` postfix. [#7880](https://github.com/ClickHouse/ClickHouse/pull/7880) ([Andrey Konyaev](https://github.com/akonyaev90))
+* Simplify format of the header of data sending to a shard in a distributed query. [#8044](https://github.com/ClickHouse/ClickHouse/pull/8044) ([Vitaly Baranov](https://github.com/vitlibar))
+* `Live View` table engine refactoring. [#8519](https://github.com/ClickHouse/ClickHouse/pull/8519) ([vzakaznikov](https://github.com/vzakaznikov))
+* Add additional checks for external dictionaries created from DDL-queries. [#8127](https://github.com/ClickHouse/ClickHouse/pull/8127) ([alesapin](https://github.com/alesapin))
+* Fix error `Column ... already exists` while using `FINAL` and `SAMPLE` together, e.g. `select count() from table final sample 1/2`. Fixes [#5186](https://github.com/ClickHouse/ClickHouse/issues/5186). [#7907](https://github.com/ClickHouse/ClickHouse/pull/7907) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Now table the first argument of `joinGet` function can be table identifier. [#7707](https://github.com/ClickHouse/ClickHouse/pull/7707) ([Amos Bird](https://github.com/amosbird))
+* Allow using `MaterializedView` with subqueries above `Kafka` tables. [#8197](https://github.com/ClickHouse/ClickHouse/pull/8197) ([filimonov](https://github.com/filimonov))
+* Now background moves between disks run it the seprate thread pool. [#7670](https://github.com/ClickHouse/ClickHouse/pull/7670) ([Vladimir Chebotarev](https://github.com/excitoon))
+* `SYSTEM RELOAD DICTIONARY` now executes synchronously. [#8240](https://github.com/ClickHouse/ClickHouse/pull/8240) ([Vitaly Baranov](https://github.com/vitlibar))
+* Stack traces now display physical addresses (offsets in object file) instead of virtual memory addresses (where the object file was loaded). That allows the use of `addr2line` when binary is position independent and ASLR is active. This fixes [#8360](https://github.com/ClickHouse/ClickHouse/issues/8360). [#8387](https://github.com/ClickHouse/ClickHouse/pull/8387) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Support new syntax for row-level security filters: `<table name='table_name'>…</table>`. Fixes [#5779](https://github.com/ClickHouse/ClickHouse/issues/5779). [#8381](https://github.com/ClickHouse/ClickHouse/pull/8381) ([Ivan](https://github.com/abyss7))
+* Now `cityHash` function can work with `Decimal` and `UUID` types. Fixes [#5184](https://github.com/ClickHouse/ClickHouse/issues/5184). [#7693](https://github.com/ClickHouse/ClickHouse/pull/7693) ([Mikhail Korotov](https://github.com/millb))
+* Removed fixed index granularity (it was 1024) from system logs because it's obsolete after implementation of adaptive granularity. [#7698](https://github.com/ClickHouse/ClickHouse/pull/7698) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Enabled MySQL compatibility server when ClickHouse is compiled without SSL. [#7852](https://github.com/ClickHouse/ClickHouse/pull/7852) ([Yuriy Baranov](https://github.com/yurriy))
+* Now server checksums distributed batches, which gives more verbose errors in case of corrupted data in batch. [#7914](https://github.com/ClickHouse/ClickHouse/pull/7914) ([Azat Khuzhin](https://github.com/azat))
+* Support `DROP DATABASE`, `DETACH TABLE`, `DROP TABLE` and `ATTACH TABLE` for `MySQL` database engine. [#8202](https://github.com/ClickHouse/ClickHouse/pull/8202) ([Winter Zhang](https://github.com/zhang2014))
+* Add authentication in S3 table function and table engine. [#7623](https://github.com/ClickHouse/ClickHouse/pull/7623) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Added check for extra parts of `MergeTree` at different disks, in order to not allow to miss data parts at undefined disks. [#8118](https://github.com/ClickHouse/ClickHouse/pull/8118) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Enable SSL support for Mac client and server. [#8297](https://github.com/ClickHouse/ClickHouse/pull/8297) ([Ivan](https://github.com/abyss7))
+* Now ClickHouse can work as MySQL federated server (see https://dev.mysql.com/doc/refman/5.7/en/federated-create-server.html). [#7717](https://github.com/ClickHouse/ClickHouse/pull/7717) ([Maxim Fedotov](https://github.com/MaxFedotov))
+* `clickhouse-client` now only enable `bracketed-paste` when multiquery is on and multiline is off. This fixes [#7757](https://github.com/ClickHouse/ClickHouse/issues/7757). [#7761](https://github.com/ClickHouse/ClickHouse/pull/7761) ([Amos Bird](https://github.com/amosbird))
+* Support `Array(Decimal)` in `if` function. [#7721](https://github.com/ClickHouse/ClickHouse/pull/7721) ([Artem Zuikov](https://github.com/4ertus2))
+* Support Decimals in `arrayDifference`, `arrayCumSum` and `arrayCumSumNegative` functions. [#7724](https://github.com/ClickHouse/ClickHouse/pull/7724) ([Artem Zuikov](https://github.com/4ertus2))
+* Added `lifetime` column to `system.dictionaries` table. [#6820](https://github.com/ClickHouse/ClickHouse/issues/6820) [#7727](https://github.com/ClickHouse/ClickHouse/pull/7727) ([kekekekule](https://github.com/kekekekule))
+* Improved check for existing parts on different disks for `*MergeTree` table engines. Addresses [#7660](https://github.com/ClickHouse/ClickHouse/issues/7660). [#8440](https://github.com/ClickHouse/ClickHouse/pull/8440) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Integration with `AWS SDK` for `S3` interactions which allows to use all S3 features out of the box. [#8011](https://github.com/ClickHouse/ClickHouse/pull/8011) ([Pavel Kovalenko](https://github.com/Jokser))
+* Added support for subqueries in `Live View` tables. [#7792](https://github.com/ClickHouse/ClickHouse/pull/7792) ([vzakaznikov](https://github.com/vzakaznikov))
+* Check for using `Date` or `DateTime` column from `TTL` expressions was removed. [#7920](https://github.com/ClickHouse/ClickHouse/pull/7920) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Information about disk was added to `system.detached_parts` table. [#7833](https://github.com/ClickHouse/ClickHouse/pull/7833) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Now settings `max_(table|partition)_size_to_drop` can be changed without a restart. [#7779](https://github.com/ClickHouse/ClickHouse/pull/7779) ([Grigory Pervakov](https://github.com/GrigoryPervakov))
+* Slightly better usability of error messages. Ask user not to remove the lines below `Stack trace:`. [#7897](https://github.com/ClickHouse/ClickHouse/pull/7897) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Better reading messages from `Kafka` engine in various formats after [#7935](https://github.com/ClickHouse/ClickHouse/issues/7935). [#8035](https://github.com/ClickHouse/ClickHouse/pull/8035) ([Ivan](https://github.com/abyss7))
+* Better compatibility with MySQL clients which don't support `sha2_password` auth plugin. [#8036](https://github.com/ClickHouse/ClickHouse/pull/8036) ([Yuriy Baranov](https://github.com/yurriy))
+* Support more column types in MySQL compatibility server. [#7975](https://github.com/ClickHouse/ClickHouse/pull/7975) ([Yuriy Baranov](https://github.com/yurriy))
+* Implement `ORDER BY` optimization for `Merge`, `Buffer` and `Materilized View` storages with underlying `MergeTree` tables. [#8130](https://github.com/ClickHouse/ClickHouse/pull/8130) ([Anton Popov](https://github.com/CurtizJ))
+* Now we always use POSIX implementation of `getrandom` to have better compatibility with old kernels (< 3.17). [#7940](https://github.com/ClickHouse/ClickHouse/pull/7940) ([Amos Bird](https://github.com/amosbird))
+* Better check for valid destination in a move TTL rule. [#8410](https://github.com/ClickHouse/ClickHouse/pull/8410) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Better checks for broken insert batches for `Distributed` table engine. [#7933](https://github.com/ClickHouse/ClickHouse/pull/7933) ([Azat Khuzhin](https://github.com/azat))
+* Add column with array of parts name which mutations must process in future to `system.mutations` table. [#8179](https://github.com/ClickHouse/ClickHouse/pull/8179) ([alesapin](https://github.com/alesapin))
+* Parallel merge sort optimization for processors. [#8552](https://github.com/ClickHouse/ClickHouse/pull/8552) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* The settings `mark_cache_min_lifetime` is now obsolete and does nothing. In previous versions, mark cache can grow in memory larger than `mark_cache_size` to accomodate data within `mark_cache_min_lifetime` seconds. That was leading to confusion and higher memory usage than expected, that is especially bad on memory constrained systems. If you will see performance degradation after installing this release, you should increase the `mark_cache_size`. [#8484](https://github.com/ClickHouse/ClickHouse/pull/8484) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Preparation to use `tid` everywhere. This is needed for [#7477](https://github.com/ClickHouse/ClickHouse/issues/7477). [#8276](https://github.com/ClickHouse/ClickHouse/pull/8276) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+#### Performance Improvement
+* Performance optimizations in processors pipeline. [#7988](https://github.com/ClickHouse/ClickHouse/pull/7988) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Non-blocking updates of expired keys in cache dictionaries (with permission to read old ones). [#8303](https://github.com/ClickHouse/ClickHouse/pull/8303) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Compile ClickHouse without `-fno-omit-frame-pointer` globally to spare one more register. [#8097](https://github.com/ClickHouse/ClickHouse/pull/8097) ([Amos Bird](https://github.com/amosbird))
+* Speedup `greatCircleDistance` function and add performance tests for it. [#7307](https://github.com/ClickHouse/ClickHouse/pull/7307) ([Olga Khvostikova](https://github.com/stavrolia))
+* Improved performance of function `roundDown`. [#8465](https://github.com/ClickHouse/ClickHouse/pull/8465) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Improved performance of `max`, `min`, `argMin`, `argMax` for `DateTime64` data type. [#8199](https://github.com/ClickHouse/ClickHouse/pull/8199) ([Vasily Nemkov](https://github.com/Enmk))
+* Improved performance of sorting without a limit or with big limit and external sorting. [#8545](https://github.com/ClickHouse/ClickHouse/pull/8545) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Improved performance of formatting floating point numbers up to 6 times. [#8542](https://github.com/ClickHouse/ClickHouse/pull/8542) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Improved performance of `modulo` function. [#7750](https://github.com/ClickHouse/ClickHouse/pull/7750) ([Amos Bird](https://github.com/amosbird))
+* Optimized `ORDER BY` and merging with single column key. [#8335](https://github.com/ClickHouse/ClickHouse/pull/8335) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Better implementation for `arrayReduce`, `-Array` and `-State` combinators.  [#7710](https://github.com/ClickHouse/ClickHouse/pull/7710) ([Amos Bird](https://github.com/amosbird))
+* Now `PREWHERE` should be optimized to be at least as efficient as `WHERE`. [#7769](https://github.com/ClickHouse/ClickHouse/pull/7769) ([Amos Bird](https://github.com/amosbird))
+* Improve the way `round` and `roundBankers` handling negative numbers. [#8229](https://github.com/ClickHouse/ClickHouse/pull/8229) ([hcz](https://github.com/hczhcz))
+* Improved decoding performance of `DoubleDelta` and `Gorilla` codecs by roughly 30-40%. This fixes [#7082](https://github.com/ClickHouse/ClickHouse/issues/7082). [#8019](https://github.com/ClickHouse/ClickHouse/pull/8019) ([Vasily Nemkov](https://github.com/Enmk))
+* Improved performance of `base64` related functions. [#8444](https://github.com/ClickHouse/ClickHouse/pull/8444) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Added a function `geoDistance`. It is similar to `greatCircleDistance` but uses approximation to WGS-84 ellipsoid model. The performance of both functions are near the same. [#8086](https://github.com/ClickHouse/ClickHouse/pull/8086) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Faster `min` and `max` aggregation functions for `Decimal` data type. [#8144](https://github.com/ClickHouse/ClickHouse/pull/8144) ([Artem Zuikov](https://github.com/4ertus2))
+* Vectorize processing `arrayReduce`. [#7608](https://github.com/ClickHouse/ClickHouse/pull/7608) ([Amos Bird](https://github.com/amosbird))
+* `if` chains are now optimized as `multiIf`. [#8355](https://github.com/ClickHouse/ClickHouse/pull/8355) ([kamalov-ruslan](https://github.com/kamalov-ruslan))
+* Fix performance regression of `Kafka` table engine introduced in 19.15. This fixes [#7261](https://github.com/ClickHouse/ClickHouse/issues/7261). [#7935](https://github.com/ClickHouse/ClickHouse/pull/7935) ([filimonov](https://github.com/filimonov))
+* Removed "pie" code generation that `gcc` from Debian packages occasionally brings by default. [#8483](https://github.com/ClickHouse/ClickHouse/pull/8483) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Parallel parsing data formats [#6553](https://github.com/ClickHouse/ClickHouse/pull/6553) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
+* Enable optimized parser of `Values` with expressions by default (`input_format_values_deduce_templates_of_expressions=1`). [#8231](https://github.com/ClickHouse/ClickHouse/pull/8231) ([tavplubix](https://github.com/tavplubix))
+
+#### Build/Testing/Packaging Improvement
+* Build fixes for `ARM` and in minimal mode. [#8304](https://github.com/ClickHouse/ClickHouse/pull/8304) ([proller](https://github.com/proller))
+* Add coverage file flush for `clickhouse-server` when std::atexit is not called. Also slightly improved logging in stateless tests with coverage. [#8267](https://github.com/ClickHouse/ClickHouse/pull/8267) ([alesapin](https://github.com/alesapin))
+* Update LLVM library in contrib. Avoid using LLVM from OS packages. [#8258](https://github.com/ClickHouse/ClickHouse/pull/8258) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Make bundled `curl` build fully quiet. [#8232](https://github.com/ClickHouse/ClickHouse/pull/8232) [#8203](https://github.com/ClickHouse/ClickHouse/pull/8203) ([Pavel Kovalenko](https://github.com/Jokser))
+* Fix some `MemorySanitizer` warnings. [#8235](https://github.com/ClickHouse/ClickHouse/pull/8235) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Use `add_warning` and `no_warning` macros in `CMakeLists.txt`. [#8604](https://github.com/ClickHouse/ClickHouse/pull/8604) ([Ivan](https://github.com/abyss7))
+* Add support of Minio S3 Compatible object (https://min.io/) for better integration tests. [#7863](https://github.com/ClickHouse/ClickHouse/pull/7863) [#7875](https://github.com/ClickHouse/ClickHouse/pull/7875) ([Pavel Kovalenko](https://github.com/Jokser))
+* Imported `libc` headers to contrib. It allows to make builds more consistent across various systems (only for `x86_64-linux-gnu`). [#5773](https://github.com/ClickHouse/ClickHouse/pull/5773) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Remove `-fPIC` from some libraries. [#8464](https://github.com/ClickHouse/ClickHouse/pull/8464) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Clean `CMakeLists.txt` for curl. See https://github.com/ClickHouse/ClickHouse/pull/8011#issuecomment-569478910 [#8459](https://github.com/ClickHouse/ClickHouse/pull/8459) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Silent warnings in `CapNProto` library. [#8220](https://github.com/ClickHouse/ClickHouse/pull/8220) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Add performance tests for short string optimized hash tables. [#7679](https://github.com/ClickHouse/ClickHouse/pull/7679) ([Amos Bird](https://github.com/amosbird))
+* Now ClickHouse will build on `AArch64` even if `MADV_FREE` is not available. This fixes [#8027](https://github.com/ClickHouse/ClickHouse/issues/8027). [#8243](https://github.com/ClickHouse/ClickHouse/pull/8243) ([Amos Bird](https://github.com/amosbird))
+* Update `zlib-ng` to fix memory sanitizer problems. [#7182](https://github.com/ClickHouse/ClickHouse/pull/7182) [#8206](https://github.com/ClickHouse/ClickHouse/pull/8206) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Enable internal MySQL library on non-Linux system, because usage of OS packages is very fragile and usually does not work at all. This fixes [#5765](https://github.com/ClickHouse/ClickHouse/issues/5765). [#8426](https://github.com/ClickHouse/ClickHouse/pull/8426) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed build on some systems after enabling `libc++`. This supersedes [#8374](https://github.com/ClickHouse/ClickHouse/issues/8374). [#8380](https://github.com/ClickHouse/ClickHouse/pull/8380) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Make `Field` methods more type-safe to find more errors. [#7386](https://github.com/ClickHouse/ClickHouse/pull/7386) [#8209](https://github.com/ClickHouse/ClickHouse/pull/8209) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Added missing files to the `libc-headers` submodule. [#8507](https://github.com/ClickHouse/ClickHouse/pull/8507) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix wrong `JSON` quoting in performance test output. [#8497](https://github.com/ClickHouse/ClickHouse/pull/8497) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Now stack trace is displayed for `std::exception` and `Poco::Exception`. In previous versions it was available only for `DB::Exception`. This improves diagnostics. [#8501](https://github.com/ClickHouse/ClickHouse/pull/8501) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Porting `clock_gettime` and `clock_nanosleep` for fresh glibc versions. [#8054](https://github.com/ClickHouse/ClickHouse/pull/8054) ([Amos Bird](https://github.com/amosbird))
+* Enable `part_log` in example config for developers. [#8609](https://github.com/ClickHouse/ClickHouse/pull/8609) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix async nature of reload in `01036_no_superfluous_dict_reload_on_create_database*`. [#8111](https://github.com/ClickHouse/ClickHouse/pull/8111) ([Azat Khuzhin](https://github.com/azat))
+* Fixed codec performance tests. [#8615](https://github.com/ClickHouse/ClickHouse/pull/8615) ([Vasily Nemkov](https://github.com/Enmk))
+* Add install scripts for `.tgz` build and documentation for them. [#8612](https://github.com/ClickHouse/ClickHouse/pull/8612) [#8591](https://github.com/ClickHouse/ClickHouse/pull/8591) ([alesapin](https://github.com/alesapin))
+* Removed old `ZSTD` test (it was created in year 2016 to reproduce the bug that pre 1.0 version of ZSTD has had). This fixes [#8618](https://github.com/ClickHouse/ClickHouse/issues/8618). [#8619](https://github.com/ClickHouse/ClickHouse/pull/8619) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed build on Mac OS Catalina. [#8600](https://github.com/ClickHouse/ClickHouse/pull/8600) ([meo](https://github.com/meob))
+* Increased number of rows in codec performance tests to make results noticeable. [#8574](https://github.com/ClickHouse/ClickHouse/pull/8574) ([Vasily Nemkov](https://github.com/Enmk))
+* In debug builds, treat `LOGICAL_ERROR` exceptions as assertion failures, so that they are easier to notice. [#8475](https://github.com/ClickHouse/ClickHouse/pull/8475) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Make formats-related performance test more deterministic. [#8477](https://github.com/ClickHouse/ClickHouse/pull/8477) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Update `lz4` to fix a MemorySanitizer failure. [#8181](https://github.com/ClickHouse/ClickHouse/pull/8181) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Suppress a known MemorySanitizer false positive in exception handling. [#8182](https://github.com/ClickHouse/ClickHouse/pull/8182) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Update `gcc` and `g++` to version 9 in `build/docker/build.sh` [#7766](https://github.com/ClickHouse/ClickHouse/pull/7766) ([TLightSky](https://github.com/tlightsky))
+* Add performance test case to test that `PREWHERE` is worse than `WHERE`.  [#7768](https://github.com/ClickHouse/ClickHouse/pull/7768) ([Amos Bird](https://github.com/amosbird))
+* Progress towards fixing one flacky test. [#8621](https://github.com/ClickHouse/ClickHouse/pull/8621) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Avoid MemorySanitizer report for data from `libunwind`. [#8539](https://github.com/ClickHouse/ClickHouse/pull/8539) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Updated `libc++` to the latest version. [#8324](https://github.com/ClickHouse/ClickHouse/pull/8324) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Build ICU library from sources. This fixes [#6460](https://github.com/ClickHouse/ClickHouse/issues/6460). [#8219](https://github.com/ClickHouse/ClickHouse/pull/8219) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Switched from `libressl` to `openssl`. ClickHouse should support TLS 1.3 and SNI after this change. This fixes [#8171](https://github.com/ClickHouse/ClickHouse/issues/8171). [#8218](https://github.com/ClickHouse/ClickHouse/pull/8218) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixed UBSan report when using `chacha20_poly1305` from SSL (happens on connect to https://yandex.ru/). [#8214](https://github.com/ClickHouse/ClickHouse/pull/8214) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix mode of default password file for `.deb` linux distros. [#8075](https://github.com/ClickHouse/ClickHouse/pull/8075) ([proller](https://github.com/proller))
+* Improved expression for getting `clickhouse-server` PID in `clickhouse-test`. [#8063](https://github.com/ClickHouse/ClickHouse/pull/8063) ([Alexander Kazakov](https://github.com/Akazz))
+* Updated contrib/googletest to v1.10.0. [#8587](https://github.com/ClickHouse/ClickHouse/pull/8587) ([Alexander Burmak](https://github.com/Alex-Burmak))
+* Fixed ThreadSaninitizer report in `base64` library. Also updated this library to the latest version, but it does not matter. This fixes [#8397](https://github.com/ClickHouse/ClickHouse/issues/8397). [#8403](https://github.com/ClickHouse/ClickHouse/pull/8403) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fix `00600_replace_running_query` for processors. [#8272](https://github.com/ClickHouse/ClickHouse/pull/8272) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Remove support for `tcmalloc` to make `CMakeLists.txt` simpler. [#8310](https://github.com/ClickHouse/ClickHouse/pull/8310) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Release gcc builds now use `libc++` instead of `libstdc++`. Recently `libc++` was used only with clang. This will improve consistency of build configurations and portability. [#8311](https://github.com/ClickHouse/ClickHouse/pull/8311) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Enable ICU library for build with MemorySanitizer. [#8222](https://github.com/ClickHouse/ClickHouse/pull/8222) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Suppress warnings from `CapNProto` library. [#8224](https://github.com/ClickHouse/ClickHouse/pull/8224) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Removed special cases of code for `tcmalloc`, because it's no longer supported. [#8225](https://github.com/ClickHouse/ClickHouse/pull/8225) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* In CI coverage task, kill the server gracefully to allow it to save the coverage report. This fixes incomplete coverage reports we've been seeing lately. [#8142](https://github.com/ClickHouse/ClickHouse/pull/8142) ([alesapin](https://github.com/alesapin))
+* Performance tests for all codecs against `Float64` and `UInt64` values. [#8349](https://github.com/ClickHouse/ClickHouse/pull/8349) ([Vasily Nemkov](https://github.com/Enmk))
+* `termcap` is very much deprecated and lead to various problems (f.g. missing "up" cap and echoing `^J` instead of multi line) . Favor `terminfo` or bundled `ncurses`. [#7737](https://github.com/ClickHouse/ClickHouse/pull/7737) ([Amos Bird](https://github.com/amosbird))
+* Fix `test_storage_s3` integration test. [#7734](https://github.com/ClickHouse/ClickHouse/pull/7734) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Support `StorageFile(<format>, null) ` to insert block into given format file without actually write to disk. This is required for performance tests. [#8455](https://github.com/ClickHouse/ClickHouse/pull/8455) ([Amos Bird](https://github.com/amosbird))
+* Added argument `--print-time` to functional tests which prints execution time per test. [#8001](https://github.com/ClickHouse/ClickHouse/pull/8001) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Added asserts to `KeyCondition` while evaluating RPN. This will fix warning from gcc-9. [#8279](https://github.com/ClickHouse/ClickHouse/pull/8279) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Dump cmake options in CI builds. [#8273](https://github.com/ClickHouse/ClickHouse/pull/8273) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Don't generate debug info for some fat libraries. [#8271](https://github.com/ClickHouse/ClickHouse/pull/8271) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Make `log_to_console.xml` always log to stderr, regardless of is it interactive or not. [#8395](https://github.com/ClickHouse/ClickHouse/pull/8395) ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Removed some unused features from `clickhouse-performance-test` tool. [#8555](https://github.com/ClickHouse/ClickHouse/pull/8555) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Now we will also search for `lld-X` with corresponding `clang-X` version. [#8092](https://github.com/ClickHouse/ClickHouse/pull/8092) ([alesapin](https://github.com/alesapin))
+* Parquet build improvement. [#8421](https://github.com/ClickHouse/ClickHouse/pull/8421) ([maxulan](https://github.com/maxulan))
+* More GCC warnings [#8221](https://github.com/ClickHouse/ClickHouse/pull/8221) ([kreuzerkrieg](https://github.com/kreuzerkrieg))
+* Package for Arch Linux now allows to run ClickHouse server, and not only client. [#8534](https://github.com/ClickHouse/ClickHouse/pull/8534) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fix test with processors. Tiny performance fixes. [#7672](https://github.com/ClickHouse/ClickHouse/pull/7672) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Update contrib/protobuf. [#8256](https://github.com/ClickHouse/ClickHouse/pull/8256) ([Matwey V. Kornilov](https://github.com/matwey))
+* In preparation of switching to c++20 as a new year celebration. "May the C++ force be with ClickHouse." [#8447](https://github.com/ClickHouse/ClickHouse/pull/8447) ([Amos Bird](https://github.com/amosbird))
+
+#### Experimental Feature
+* Added experimental setting `min_bytes_to_use_mmap_io`. It allows to read big files without copying data from kernel to userspace. The setting is disabled by default. Recommended threshold is about 64 MB, because mmap/munmap is slow. [#8520](https://github.com/ClickHouse/ClickHouse/pull/8520) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Reworked quotas as a part of access control system. Added new table `system.quotas`, new functions `currentQuota`, `currentQuotaKey`, new SQL syntax `CREATE QUOTA`, `ALTER QUOTA`, `DROP QUOTA`, `SHOW QUOTA`. [#7257](https://github.com/ClickHouse/ClickHouse/pull/7257) ([Vitaly Baranov](https://github.com/vitlibar))
+* Allow skipping unknown settings with warnings instead of throwing exceptions. [#7653](https://github.com/ClickHouse/ClickHouse/pull/7653) ([Vitaly Baranov](https://github.com/vitlibar))
+* Reworked row policies as a part of access control system. Added new table `system.row_policies`, new function `currentRowPolicies()`, new SQL syntax `CREATE POLICY`, `ALTER POLICY`, `DROP POLICY`, `SHOW CREATE POLICY`, `SHOW POLICIES`. [#7808](https://github.com/ClickHouse/ClickHouse/pull/7808) ([Vitaly Baranov](https://github.com/vitlibar))
+
+#### Security Fix
+* Fixed the possibility of reading directories structure in tables with `File` table engine. This fixes [#8536](https://github.com/ClickHouse/ClickHouse/issues/8536). [#8537](https://github.com/ClickHouse/ClickHouse/pull/8537) ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+## [Changelog for 2019](https://github.com/ClickHouse/ClickHouse/blob/master/docs/en/whats-new/changelog/2019.md)
diff --git a/docs/en/reference/whats-new/changelog/2021.md b/docs/en/reference/whats-new/changelog/2021.md
new file mode 100644
index 00000000000..2e81d981990
--- /dev/null
+++ b/docs/en/reference/whats-new/changelog/2021.md
@@ -0,0 +1,2053 @@
+---
+toc_priority: 75
+toc_title: '2021'
+---
+
+### ClickHouse release v21.12, 2021-12-15
+
+#### Backward Incompatible Change
+
+* *A fix for a feature that previously had unwanted behaviour.* Do not allow direct select for Kafka/RabbitMQ/FileLog. Can be enabled by setting `stream_like_engine_allow_direct_select`. Direct select will be not allowed even if enabled by setting, in case there is an attached materialized view. For Kafka and RabbitMQ direct selectm if allowed, will not commit massages by default. To enable commits with direct select, user must use storage level setting `kafka{rabbitmq}_commit_on_select=1` (default `0`). [#31053](https://github.com/ClickHouse/ClickHouse/pull/31053) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* *A slight change in behaviour of a new function.* Return unquoted string in JSON_VALUE. Closes [#27965](https://github.com/ClickHouse/ClickHouse/issues/27965). [#31008](https://github.com/ClickHouse/ClickHouse/pull/31008) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* *Setting rename.* Add custom null representation support for TSV/CSV input formats. Fix deserialing Nullable(String) in TSV/CSV/JSONCompactStringsEachRow/JSONStringsEachRow input formats. Rename `output_format_csv_null_representation` and `output_format_tsv_null_representation` to `format_csv_null_representation` and `format_tsv_null_representation` accordingly. [#30497](https://github.com/ClickHouse/ClickHouse/pull/30497) ([Kruglov Pavel](https://github.com/Avogar)).
+* *Further deprecation of already unused code.* This is relevant only for users of ClickHouse versions older than 20.6. A "leader election" mechanism is removed from `ReplicatedMergeTree`, because multiple leaders are supported since 20.6. If you are upgrading from an older version and some replica with an old version is a leader, then server will fail to start after upgrade. Stop replicas with old version to make new version start. After that it will not be possible to downgrade to version older than 20.6. [#32140](https://github.com/ClickHouse/ClickHouse/pull/32140) ([tavplubix](https://github.com/tavplubix)).
+
+#### New Feature
+
+* Implemented more of the ZooKeeper Four Letter Words commands in clickhouse-keeper: https://zookeeper.apache.org/doc/r3.4.8/zookeeperAdmin.html#sc_zkCommands. [#28981](https://github.com/ClickHouse/ClickHouse/pull/28981) ([JackyWoo](https://github.com/JackyWoo)). Now `clickhouse-keeper` is feature complete.
+* Support for `Bool` data type. [#31072](https://github.com/ClickHouse/ClickHouse/pull/31072) ([kevin wan](https://github.com/MaxWk)).
+* Support for `PARTITION BY` in File, URL, HDFS storages and with `INSERT INTO` table function. Closes [#30273](https://github.com/ClickHouse/ClickHouse/issues/30273). [#30690](https://github.com/ClickHouse/ClickHouse/pull/30690) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Added `CONSTRAINT ... ASSUME ...` (without checking during `INSERT`). Added query transformation to CNF (https://github.com/ClickHouse/ClickHouse/issues/11749) for more convenient optimization. Added simple query rewriting using constraints (only simple matching now, will be improved to support <,=,>... later). Added ability to replace heavy columns with light columns if it's possible. [#18787](https://github.com/ClickHouse/ClickHouse/pull/18787) ([Nikita Vasilev](https://github.com/nikvas0)).
+* Basic access authentication for http/url functions. [#31648](https://github.com/ClickHouse/ClickHouse/pull/31648) ([michael1589](https://github.com/michael1589)).
+* Support `INTERVAL` type in `STEP` clause for `WITH FILL` modifier. [#30927](https://github.com/ClickHouse/ClickHouse/pull/30927) ([Anton Popov](https://github.com/CurtizJ)).
+* Add support for parallel reading from multiple files and support globs in `FROM INFILE` clause. [#30135](https://github.com/ClickHouse/ClickHouse/pull/30135) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
+* Add support for `Identifier` table and database query parameters. Closes [#27226](https://github.com/ClickHouse/ClickHouse/issues/27226). [#28668](https://github.com/ClickHouse/ClickHouse/pull/28668) ([Nikolay Degterinsky](https://github.com/evillique)).
+* *TLDR: Major improvements of completeness and consistency of text formats.* Refactor formats `TSV`, `TSVRaw`, `CSV` and `JSONCompactEachRow`, `JSONCompactStringsEachRow`, remove code duplication, add base interface for formats with `-WithNames` and `-WithNamesAndTypes` suffixes. Add formats `CSVWithNamesAndTypes`, `TSVRawWithNames`, `TSVRawWithNamesAndTypes`, `JSONCompactEachRowWIthNames`, `JSONCompactStringsEachRowWIthNames`, `RowBinaryWithNames`. Support parallel parsing for formats `TSVWithNamesAndTypes`, `TSVRaw(WithNames/WIthNamesAndTypes)`, `CSVWithNamesAndTypes`, `JSONCompactEachRow(WithNames/WIthNamesAndTypes)`, `JSONCompactStringsEachRow(WithNames/WIthNamesAndTypes)`. Support columns mapping and types checking for `RowBinaryWithNamesAndTypes` format. Add setting `input_format_with_types_use_header` which specify if we should check that types written in <format_name>`WIthNamesAndTypes` format matches with table structure. Add setting `input_format_csv_empty_as_default` and use it in CSV format instead of `input_format_defaults_for_omitted_fields` (because this setting should not control `csv_empty_as_default`). Fix usage of setting `input_format_defaults_for_omitted_fields` (it was used only as `csv_empty_as_default`, but it should control calculation of default expressions for omitted fields). Fix Nullable input/output in `TSVRaw` format, make this format fully compatible with inserting into TSV. Fix inserting NULLs in `LowCardinality(Nullable)` when `input_format_null_as_default` is enabled (previously default values was inserted instead of actual NULLs). Fix strings deserialization in `JSONStringsEachRow`/`JSONCompactStringsEachRow` formats (strings were parsed just until first '\n' or '\t'). Add ability to use `Raw` escaping rule in Template input format. Add diagnostic info for JSONCompactEachRow(WithNames/WIthNamesAndTypes) input format. Fix bug with parallel parsing of `-WithNames` formats in case when setting `min_chunk_bytes_for_parallel_parsing` is less than bytes in a single row. [#30178](https://github.com/ClickHouse/ClickHouse/pull/30178) ([Kruglov Pavel](https://github.com/Avogar)). Allow to print/parse names and types of colums in `CustomSeparated` input/output format. Add formats `CustomSeparatedWithNames/WithNamesAndTypes` similar to `TSVWithNames/WithNamesAndTypes`. [#31434](https://github.com/ClickHouse/ClickHouse/pull/31434) ([Kruglov Pavel](https://github.com/Avogar)).
+* Aliyun OSS Storage support. [#31286](https://github.com/ClickHouse/ClickHouse/pull/31286) ([cfcz48](https://github.com/cfcz48)).
+* Exposes all settings of the global thread pool in the configuration file. [#31285](https://github.com/ClickHouse/ClickHouse/pull/31285) ([Tomáš Hromada](https://github.com/gyfis)).
+* Introduced window functions `exponentialTimeDecayedSum`, `exponentialTimeDecayedMax`, `exponentialTimeDecayedCount` and `exponentialTimeDecayedAvg` which are more effective than `exponentialMovingAverage` for bigger windows. Also more use-cases were covered. [#29799](https://github.com/ClickHouse/ClickHouse/pull/29799) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Add option to compress logs before writing them to a file using LZ4. Closes [#23860](https://github.com/ClickHouse/ClickHouse/issues/23860). [#29219](https://github.com/ClickHouse/ClickHouse/pull/29219) ([Nikolay Degterinsky](https://github.com/evillique)).
+* Support `JOIN ON 1 = 1` that have CROSS JOIN semantic. This closes [#25578](https://github.com/ClickHouse/ClickHouse/issues/25578). [#25894](https://github.com/ClickHouse/ClickHouse/pull/25894) ([Vladimir C](https://github.com/vdimir)).
+* Add Map combinator for `Map` type. - Rename old `sum-, min-, max- Map` for mapped arrays to `sum-, min-, max- MappedArrays`. [#24539](https://github.com/ClickHouse/ClickHouse/pull/24539) ([Ildus Kurbangaliev](https://github.com/ildus)).
+* Make reading from HTTP retriable. Closes [#29696](https://github.com/ClickHouse/ClickHouse/issues/29696). [#29894](https://github.com/ClickHouse/ClickHouse/pull/29894) ([Kseniia Sumarokova](https://github.com/kssenii)).
+
+#### Experimental Feature
+
+* `WINDOW VIEW` to enable stream processing in ClickHouse. [#8331](https://github.com/ClickHouse/ClickHouse/pull/8331) ([vxider](https://github.com/Vxider)).
+* Drop support for using Ordinary databases with `MaterializedMySQL`. [#31292](https://github.com/ClickHouse/ClickHouse/pull/31292) ([Stig Bakken](https://github.com/stigsb)).
+* Implement the commands BACKUP and RESTORE for the Log family. This feature is under development. [#30688](https://github.com/ClickHouse/ClickHouse/pull/30688) ([Vitaly Baranov](https://github.com/vitlibar)).
+
+#### Performance Improvement
+
+* Reduce memory usage when reading with `s3` / `url` / `hdfs` formats `Parquet`, `ORC`, `Arrow` (controlled by setting `input_format_allow_seeks`, enabled by default). Also add setting `remote_read_min_bytes_for_seek` to control seeks. Closes [#10461](https://github.com/ClickHouse/ClickHouse/issues/10461). Closes [#16857](https://github.com/ClickHouse/ClickHouse/issues/16857). [#30936](https://github.com/ClickHouse/ClickHouse/pull/30936) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add optimizations for constant conditions in JOIN ON, ref [#26928](https://github.com/ClickHouse/ClickHouse/issues/26928). [#27021](https://github.com/ClickHouse/ClickHouse/pull/27021) ([Vladimir C](https://github.com/vdimir)).
+* Support parallel formatting for all text formats, except `JSONEachRowWithProgress` and `PrettyCompactMonoBlock`. [#31489](https://github.com/ClickHouse/ClickHouse/pull/31489) ([Kruglov Pavel](https://github.com/Avogar)).
+* Speed up count over nullable columns. [#31806](https://github.com/ClickHouse/ClickHouse/pull/31806) ([Raúl Marín](https://github.com/Algunenano)).
+* Speed up `avg` and `sumCount` aggregate functions. [#31694](https://github.com/ClickHouse/ClickHouse/pull/31694) ([Raúl Marín](https://github.com/Algunenano)).
+* Improve performance of JSON and XML output formats. [#31673](https://github.com/ClickHouse/ClickHouse/pull/31673) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve performance of syncing data to block device. This closes [#31181](https://github.com/ClickHouse/ClickHouse/issues/31181). [#31229](https://github.com/ClickHouse/ClickHouse/pull/31229) ([zhanglistar](https://github.com/zhanglistar)).
+* Fixing query performance issue in `LiveView` tables. Fixes [#30831](https://github.com/ClickHouse/ClickHouse/issues/30831). [#31006](https://github.com/ClickHouse/ClickHouse/pull/31006) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Speed up query parsing. [#31949](https://github.com/ClickHouse/ClickHouse/pull/31949) ([Raúl Marín](https://github.com/Algunenano)).
+* Allow to split `GraphiteMergeTree` rollup rules for plain/tagged metrics (optional `rule_type` field). [#25122](https://github.com/ClickHouse/ClickHouse/pull/25122) ([Michail Safronov](https://github.com/msaf1980)).
+* Remove excessive `DESC TABLE` requests for `remote()` (in case of `remote('127.1', system.one)` (i.e. identifier as the db.table instead of string) there was excessive `DESC TABLE` request). [#32019](https://github.com/ClickHouse/ClickHouse/pull/32019) ([Azat Khuzhin](https://github.com/azat)).
+* Optimize function `tupleElement` to reading of subcolumn with enabled setting `optimize_functions_to_subcolumns`. [#31261](https://github.com/ClickHouse/ClickHouse/pull/31261) ([Anton Popov](https://github.com/CurtizJ)).
+* Optimize function `mapContains` to reading of subcolumn `key` with enabled settings `optimize_functions_to_subcolumns`. [#31218](https://github.com/ClickHouse/ClickHouse/pull/31218) ([Anton Popov](https://github.com/CurtizJ)).
+* Add settings `merge_tree_min_rows_for_concurrent_read_for_remote_filesystem` and `merge_tree_min_bytes_for_concurrent_read_for_remote_filesystem`. [#30970](https://github.com/ClickHouse/ClickHouse/pull/30970) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Skipping mutations of different partitions in `StorageMergeTree`. [#21326](https://github.com/ClickHouse/ClickHouse/pull/21326) ([Vladimir Chebotarev](https://github.com/excitoon)).
+
+#### Improvement
+
+* Do not allow to drop a table or dictionary if some tables or dictionaries depend on it. [#30977](https://github.com/ClickHouse/ClickHouse/pull/30977) ([tavplubix](https://github.com/tavplubix)).
+* Allow versioning of aggregate function states. Now we can introduce backward compatible changes in serialization format of aggregate function states. Closes [#12552](https://github.com/ClickHouse/ClickHouse/issues/12552). [#24820](https://github.com/ClickHouse/ClickHouse/pull/24820) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Support PostgreSQL style `ALTER MODIFY COLUMN` syntax. [#32003](https://github.com/ClickHouse/ClickHouse/pull/32003) ([SuperDJY](https://github.com/cmsxbc)).
+* Added `update_field` support for `RangeHashedDictionary`, `ComplexKeyRangeHashedDictionary`. [#32185](https://github.com/ClickHouse/ClickHouse/pull/32185) ([Maksim Kita](https://github.com/kitaisreal)).
+* The `murmurHash3_128` and `sipHash128` functions now accept an arbitrary number of arguments. This closes [#28774](https://github.com/ClickHouse/ClickHouse/issues/28774). [#28965](https://github.com/ClickHouse/ClickHouse/pull/28965) ([小路](https://github.com/nicelulu)).
+* Support default expression for `HDFS` storage and optimize fetching when source is column oriented. [#32256](https://github.com/ClickHouse/ClickHouse/pull/32256) ([李扬](https://github.com/taiyang-li)).
+* Improve the operation name of an opentelemetry span. [#32234](https://github.com/ClickHouse/ClickHouse/pull/32234) ([Frank Chen](https://github.com/FrankChen021)).
+* Use `Content-Type: application/x-ndjson` (http://ndjson.org/) for output format `JSONEachRow`. [#32223](https://github.com/ClickHouse/ClickHouse/pull/32223) ([Dmitriy Dorofeev](https://github.com/deem0n)).
+* Improve skipping unknown fields with quoted escaping rule in Template/CustomSeparated formats. Previously you could skip only quoted strings, now you can skip values with any type. [#32204](https://github.com/ClickHouse/ClickHouse/pull/32204) ([Kruglov Pavel](https://github.com/Avogar)).
+* Now `clickhouse-keeper` refuses to start or apply configuration changes when they contain duplicated IDs or endpoints. Fixes [#31339](https://github.com/ClickHouse/ClickHouse/issues/31339). [#32121](https://github.com/ClickHouse/ClickHouse/pull/32121) ([alesapin](https://github.com/alesapin)).
+* Set Content-Type in HTTP packets issued from URL engine. [#32113](https://github.com/ClickHouse/ClickHouse/pull/32113) ([Frank Chen](https://github.com/FrankChen021)).
+* Return Content-Type as 'application/json' for `JSONEachRow` format if `output_format_json_array_of_rows` is enabled. [#32112](https://github.com/ClickHouse/ClickHouse/pull/32112) ([Frank Chen](https://github.com/FrankChen021)).
+* Allow to parse `+` before `Float32`/`Float64` values. [#32079](https://github.com/ClickHouse/ClickHouse/pull/32079) ([Kruglov Pavel](https://github.com/Avogar)).
+* Allow a user configured `hdfs_replication` parameter for `DiskHDFS` and `StorageHDFS`. Closes [#32039](https://github.com/ClickHouse/ClickHouse/issues/32039). [#32049](https://github.com/ClickHouse/ClickHouse/pull/32049) ([leosunli](https://github.com/leosunli)).
+* Added ClickHouse `exception` and `exception_code` fields to opentelemetry span log. [#32040](https://github.com/ClickHouse/ClickHouse/pull/32040) ([Frank Chen](https://github.com/FrankChen021)).
+* Improve opentelemetry span log duration - it was is zero at the query level if there is a query exception. [#32038](https://github.com/ClickHouse/ClickHouse/pull/32038) ([Frank Chen](https://github.com/FrankChen021)).
+* Fix the issue that `LowCardinality` of `Int256` cannot be created. [#31832](https://github.com/ClickHouse/ClickHouse/pull/31832) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Recreate `system.*_log` tables in case of different engine/partition_by. [#31824](https://github.com/ClickHouse/ClickHouse/pull/31824) ([Azat Khuzhin](https://github.com/azat)).
+* `MaterializedMySQL`: Fix issue with table named 'table'. [#31781](https://github.com/ClickHouse/ClickHouse/pull/31781) ([Håvard Kvålen](https://github.com/havardk)).
+* ClickHouse dictionary source: support predefined connections. Closes [#31705](https://github.com/ClickHouse/ClickHouse/issues/31705). [#31749](https://github.com/ClickHouse/ClickHouse/pull/31749) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Allow to use predefined connections configuration for Kafka and RabbitMQ engines (the same way as for other integration table engines). [#31691](https://github.com/ClickHouse/ClickHouse/pull/31691) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Always re-render prompt while navigating history in clickhouse-client. This will improve usability of manipulating very long queries that don't fit on screen. [#31675](https://github.com/ClickHouse/ClickHouse/pull/31675) ([alexey-milovidov](https://github.com/alexey-milovidov)) (author: Amos Bird).
+* Add key bindings for navigating through history (instead of lines/history). [#31641](https://github.com/ClickHouse/ClickHouse/pull/31641) ([Azat Khuzhin](https://github.com/azat)).
+* Improve the `max_execution_time` checks. Fixed some cases when timeout checks do not happen and query could run too long. [#31636](https://github.com/ClickHouse/ClickHouse/pull/31636) ([Raúl Marín](https://github.com/Algunenano)).
+* Better exception message when `users.xml` cannot be loaded due to bad password hash. This closes [#24126](https://github.com/ClickHouse/ClickHouse/issues/24126). [#31557](https://github.com/ClickHouse/ClickHouse/pull/31557) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Use shard and replica name from `Replicated` database arguments when expanding macros in `ReplicatedMergeTree` arguments if these macros are not defined in config. Closes [#31471](https://github.com/ClickHouse/ClickHouse/issues/31471). [#31488](https://github.com/ClickHouse/ClickHouse/pull/31488) ([tavplubix](https://github.com/tavplubix)).
+* Better analysis for `min/max/count` projection. Now, with enabled `allow_experimental_projection_optimization`, virtual `min/max/count` projection can be used together with columns from partition key. [#31474](https://github.com/ClickHouse/ClickHouse/pull/31474) ([Amos Bird](https://github.com/amosbird)).
+* Add `--pager` support for `clickhouse-local`. [#31457](https://github.com/ClickHouse/ClickHouse/pull/31457) ([Azat Khuzhin](https://github.com/azat)).
+* Fix waiting of the editor during interactive query edition (`waitpid()` returns -1 on `SIGWINCH` and `EDITOR` and `clickhouse-local`/`clickhouse-client` works concurrently). [#31456](https://github.com/ClickHouse/ClickHouse/pull/31456) ([Azat Khuzhin](https://github.com/azat)).
+* Throw an exception if there is some garbage after field in `JSONCompactStrings(EachRow)` format. [#31455](https://github.com/ClickHouse/ClickHouse/pull/31455) ([Kruglov Pavel](https://github.com/Avogar)).
+* Default value of `http_send_timeout` and `http_receive_timeout` settings changed from 1800 (30 minutes) to 180 (3 minutes). [#31450](https://github.com/ClickHouse/ClickHouse/pull/31450) ([tavplubix](https://github.com/tavplubix)).
+* `MaterializedMySQL` now handles `CREATE TABLE ... LIKE ...` DDL queries. [#31410](https://github.com/ClickHouse/ClickHouse/pull/31410) ([Stig Bakken](https://github.com/stigsb)).
+* Return artificial create query when executing `show create table` on system's tables. [#31391](https://github.com/ClickHouse/ClickHouse/pull/31391) ([SuperDJY](https://github.com/cmsxbc)).
+* Previously progress was shown only for `numbers` table function. Now for `numbers_mt` it is also shown. [#31318](https://github.com/ClickHouse/ClickHouse/pull/31318) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Initial user's roles are used now to find row policies, see [#31080](https://github.com/ClickHouse/ClickHouse/issues/31080). [#31262](https://github.com/ClickHouse/ClickHouse/pull/31262) ([Vitaly Baranov](https://github.com/vitlibar)).
+* If some obsolete setting is changed - show warning in `system.warnings`. [#31252](https://github.com/ClickHouse/ClickHouse/pull/31252) ([tavplubix](https://github.com/tavplubix)).
+* Improved backoff for background cleanup tasks in `MergeTree`. Settings `merge_tree_clear_old_temporary_directories_interval_seconds` and `merge_tree_clear_old_parts_interval_seconds` moved from users settings to merge tree settings. [#31180](https://github.com/ClickHouse/ClickHouse/pull/31180) ([tavplubix](https://github.com/tavplubix)).
+* Now every replica will send to client only incremental information about profile events counters. [#31155](https://github.com/ClickHouse/ClickHouse/pull/31155) ([Dmitry Novik](https://github.com/novikd)). This makes `--hardware_utilization` option in `clickhouse-client` usable.
+* Enable multiline editing in clickhouse-client by default. This addresses [#31121](https://github.com/ClickHouse/ClickHouse/issues/31121) . [#31123](https://github.com/ClickHouse/ClickHouse/pull/31123) ([Amos Bird](https://github.com/amosbird)).
+* Function name normalization for `ALTER` queries. This helps avoid metadata mismatch between creating table with indices/projections and adding indices/projections via alter commands. This is a follow-up PR of https://github.com/ClickHouse/ClickHouse/pull/20174. Mark as improvements as there are no bug reports and the senario is somehow rare. [#31095](https://github.com/ClickHouse/ClickHouse/pull/31095) ([Amos Bird](https://github.com/amosbird)).
+* Support `IF EXISTS` modifier for `RENAME DATABASE`/`TABLE`/`DICTIONARY` query. If this directive is used, one will not get an error if the DATABASE/TABLE/DICTIONARY to be renamed doesn't exist. [#31081](https://github.com/ClickHouse/ClickHouse/pull/31081) ([victorgao](https://github.com/kafka1991)).
+* Cancel vertical merges when partition is dropped. This is a follow-up of https://github.com/ClickHouse/ClickHouse/pull/25684 and https://github.com/ClickHouse/ClickHouse/pull/30996. [#31057](https://github.com/ClickHouse/ClickHouse/pull/31057) ([Amos Bird](https://github.com/amosbird)).
+* The local session inside a Clickhouse dictionary source won't send its events to the session log anymore. This fixes a possible deadlock (tsan alert) on shutdown. Also this PR fixes flaky `test_dictionaries_dependency_xml/`. [#31013](https://github.com/ClickHouse/ClickHouse/pull/31013) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Less locking in ALTER command. [#31010](https://github.com/ClickHouse/ClickHouse/pull/31010) ([Amos Bird](https://github.com/amosbird)).
+* Fix `--verbose` option in clickhouse-local interactive mode and allow logging into file. [#30881](https://github.com/ClickHouse/ClickHouse/pull/30881) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Added `\l`, `\d`, `\c` commands in `clickhouse-client` like in MySQL and PostgreSQL. [#30876](https://github.com/ClickHouse/ClickHouse/pull/30876) ([Pavel Medvedev](https://github.com/pmed)).
+* For clickhouse-local or clickhouse-client: if there is `--interactive` option with `--query` or `--queries-file`, then first execute them like in non-interactive and then start interactive mode. [#30851](https://github.com/ClickHouse/ClickHouse/pull/30851) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix possible "The local set of parts of X doesn't look like the set of parts in ZooKeeper" error (if DROP fails during removing znodes from zookeeper). [#30826](https://github.com/ClickHouse/ClickHouse/pull/30826) ([Azat Khuzhin](https://github.com/azat)).
+* Avro format works against Kafka. Setting `output_format_avro_rows_in_file` added. [#30351](https://github.com/ClickHouse/ClickHouse/pull/30351) ([Ilya Golshtein](https://github.com/ilejn)).
+* Allow to specify one or any number of PostgreSQL schemas for one `MaterializedPostgreSQL` database. Closes [#28901](https://github.com/ClickHouse/ClickHouse/issues/28901). Closes [#29324](https://github.com/ClickHouse/ClickHouse/issues/29324). [#28933](https://github.com/ClickHouse/ClickHouse/pull/28933) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Replaced default ports for clickhouse-keeper internal communication from 44444 to 9234. Fixes [#30879](https://github.com/ClickHouse/ClickHouse/issues/30879). [#31799](https://github.com/ClickHouse/ClickHouse/pull/31799) ([alesapin](https://github.com/alesapin)).
+* Implement function transform with Decimal arguments. [#31839](https://github.com/ClickHouse/ClickHouse/pull/31839) ([李帅](https://github.com/loneylee)).
+* Fix abort in debug server and `DB::Exception: std::out_of_range: basic_string` error in release server in case of bad hdfs url by adding additional check of hdfs url structure. [#31042](https://github.com/ClickHouse/ClickHouse/pull/31042) ([Kruglov Pavel](https://github.com/Avogar)).
+* Fix possible assert in `hdfs` table function/engine, add test. [#31036](https://github.com/ClickHouse/ClickHouse/pull/31036) ([Kruglov Pavel](https://github.com/Avogar)).
+
+#### Bug Fixes
+
+* Fix group by / order by / limit by aliases with positional arguments enabled. Closes [#31173](https://github.com/ClickHouse/ClickHouse/issues/31173). [#31741](https://github.com/ClickHouse/ClickHouse/pull/31741) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix usage of `Buffer` table engine with type `Map`. Fixes [#30546](https://github.com/ClickHouse/ClickHouse/issues/30546). [#31742](https://github.com/ClickHouse/ClickHouse/pull/31742) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix reading from `MergeTree` tables with enabled `use_uncompressed_cache`. [#31826](https://github.com/ClickHouse/ClickHouse/pull/31826) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed the behavior when mutations that have nothing to do are stuck (with enabled setting `empty_result_for_aggregation_by_empty_set`). [#32358](https://github.com/ClickHouse/ClickHouse/pull/32358) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix skipping columns while writing protobuf. This PR fixes [#31160](https://github.com/ClickHouse/ClickHouse/issues/31160), see the comment [#31160](https://github.com/ClickHouse/ClickHouse/issues/31160)#issuecomment-980595318. [#31988](https://github.com/ClickHouse/ClickHouse/pull/31988) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix bug when remove unneeded columns in subquery. If there is an aggregation function in query without group by, do not remove if it is unneeded. [#32289](https://github.com/ClickHouse/ClickHouse/pull/32289) ([dongyifeng](https://github.com/dyf6372)).
+* Quota limit was not reached, but the limit was exceeded. This PR fixes [#31174](https://github.com/ClickHouse/ClickHouse/issues/31174). [#31337](https://github.com/ClickHouse/ClickHouse/pull/31337) ([sunny](https://github.com/sunny19930321)).
+* Fix SHOW GRANTS when partial revokes are used. This PR fixes [#31138](https://github.com/ClickHouse/ClickHouse/issues/31138). [#31249](https://github.com/ClickHouse/ClickHouse/pull/31249) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Memory amount was incorrectly estimated when ClickHouse is run in containers with cgroup limits. [#31157](https://github.com/ClickHouse/ClickHouse/pull/31157) ([Pavel Medvedev](https://github.com/pmed)).
+* Fix `ALTER ... MATERIALIZE COLUMN ...` queries in case when data type of default expression is not equal to the data type of column. [#32348](https://github.com/ClickHouse/ClickHouse/pull/32348) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed crash with SIGFPE in aggregate function `avgWeighted` with `Decimal` argument. Fixes [#32053](https://github.com/ClickHouse/ClickHouse/issues/32053). [#32303](https://github.com/ClickHouse/ClickHouse/pull/32303) ([tavplubix](https://github.com/tavplubix)).
+* Server might fail to start with `Cannot attach 1 tables due to cyclic dependencies` error if `Dictionary` table looks at XML-dictionary with the same name, it's fixed. Fixes [#31315](https://github.com/ClickHouse/ClickHouse/issues/31315). [#32288](https://github.com/ClickHouse/ClickHouse/pull/32288) ([tavplubix](https://github.com/tavplubix)).
+* Fix parsing error while NaN deserializing for `Nullable(Float)` for `Quoted` escaping rule. [#32190](https://github.com/ClickHouse/ClickHouse/pull/32190) ([Kruglov Pavel](https://github.com/Avogar)).
+* XML dictionaries: identifiers, used in table create query, can be qualified to `default_database` during upgrade to newer version. Closes [#31963](https://github.com/ClickHouse/ClickHouse/issues/31963). [#32187](https://github.com/ClickHouse/ClickHouse/pull/32187) ([Maksim Kita](https://github.com/kitaisreal)).
+* Number of active replicas might be determined incorrectly when inserting with quorum if setting `replicated_can_become_leader` is disabled on some replicas. It's fixed. [#32157](https://github.com/ClickHouse/ClickHouse/pull/32157) ([tavplubix](https://github.com/tavplubix)).
+* Dictionaries: fix cases when `{condition}` does not work for custom database queries. [#32117](https://github.com/ClickHouse/ClickHouse/pull/32117) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix `CAST` from `Nullable` with `cast_keep_nullable` (`PARAMETER_OUT_OF_BOUND` error before for i.e. `toUInt32OrDefault(toNullable(toUInt32(1)))`). [#32080](https://github.com/ClickHouse/ClickHouse/pull/32080) ([Azat Khuzhin](https://github.com/azat)).
+* Fix CREATE TABLE of Join Storage in some obscure cases. Close [#31680](https://github.com/ClickHouse/ClickHouse/issues/31680). [#32066](https://github.com/ClickHouse/ClickHouse/pull/32066) ([SuperDJY](https://github.com/cmsxbc)).
+* Fixed `Directory ... already exists and is not empty` error when detaching part. [#32063](https://github.com/ClickHouse/ClickHouse/pull/32063) ([tavplubix](https://github.com/tavplubix)).
+* `MaterializedMySQL` (experimental feature): Fix misinterpretation of `DECIMAL` data from MySQL. [#31990](https://github.com/ClickHouse/ClickHouse/pull/31990) ([Håvard Kvålen](https://github.com/havardk)).
+* `FileLog` (experimental feature) engine unnesessary created meta data directory when create table failed. Fix [#31962](https://github.com/ClickHouse/ClickHouse/issues/31962). [#31967](https://github.com/ClickHouse/ClickHouse/pull/31967) ([flynn](https://github.com/ucasfl)).
+* Some `GET_PART` entry might hang in replication queue if part is lost on all replicas and there are no other parts in the same partition. It's fixed in cases when partition key contains only columns of integer types or `Date[Time]`. Fixes [#31485](https://github.com/ClickHouse/ClickHouse/issues/31485). [#31887](https://github.com/ClickHouse/ClickHouse/pull/31887) ([tavplubix](https://github.com/tavplubix)).
+* Fix functions `empty` and `notEmpty` with arguments of `UUID` type. Fixes [#31819](https://github.com/ClickHouse/ClickHouse/issues/31819). [#31883](https://github.com/ClickHouse/ClickHouse/pull/31883) ([Anton Popov](https://github.com/CurtizJ)).
+* Change configuration path from `keeper_server.session_timeout_ms` to `keeper_server.coordination_settings.session_timeout_ms` when constructing a `KeeperTCPHandler`. Same with `operation_timeout`. [#31859](https://github.com/ClickHouse/ClickHouse/pull/31859) ([JackyWoo](https://github.com/JackyWoo)).
+* Fix invalid cast of Nullable type when nullable primary key is used. (Nullable primary key is a discouraged feature - please do not use). This fixes [#31075](https://github.com/ClickHouse/ClickHouse/issues/31075). [#31823](https://github.com/ClickHouse/ClickHouse/pull/31823) ([Amos Bird](https://github.com/amosbird)).
+* Fix crash in recursive UDF in SQL. Closes [#30856](https://github.com/ClickHouse/ClickHouse/issues/30856). [#31820](https://github.com/ClickHouse/ClickHouse/pull/31820) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix crash when function `dictGet` with type is used for dictionary attribute when type is `Nullable`. Fixes [#30980](https://github.com/ClickHouse/ClickHouse/issues/30980). [#31800](https://github.com/ClickHouse/ClickHouse/pull/31800) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix crash with empty result of ODBC query (with some ODBC drivers). Closes [#31465](https://github.com/ClickHouse/ClickHouse/issues/31465). [#31766](https://github.com/ClickHouse/ClickHouse/pull/31766) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix disabling query profiler (In case of `query_profiler_real_time_period_ns>0`/`query_profiler_cpu_time_period_ns>0` query profiler can stayed enabled even after query finished). [#31740](https://github.com/ClickHouse/ClickHouse/pull/31740) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed rare segfault on concurrent `ATTACH PARTITION` queries. [#31738](https://github.com/ClickHouse/ClickHouse/pull/31738) ([tavplubix](https://github.com/tavplubix)).
+* Fix race in JSONEachRowWithProgress output format when data and lines with progress are mixed in output. [#31736](https://github.com/ClickHouse/ClickHouse/pull/31736) ([Kruglov Pavel](https://github.com/Avogar)).
+* Fixed `there are no such cluster here` error on execution of `ON CLUSTER` query if specified cluster name is name of `Replicated` database. [#31723](https://github.com/ClickHouse/ClickHouse/pull/31723) ([tavplubix](https://github.com/tavplubix)).
+* Fix exception on some of the applications of `decrypt` function on Nullable columns. This closes [#31662](https://github.com/ClickHouse/ClickHouse/issues/31662). This closes [#31426](https://github.com/ClickHouse/ClickHouse/issues/31426). [#31707](https://github.com/ClickHouse/ClickHouse/pull/31707) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed function ngrams when string contains UTF-8 characters. [#31706](https://github.com/ClickHouse/ClickHouse/pull/31706) ([yandd](https://github.com/yandd)).
+* Settings `input_format_allow_errors_num` and `input_format_allow_errors_ratio` did not work for parsing of domain types, such as `IPv4`, it's fixed. Fixes [#31686](https://github.com/ClickHouse/ClickHouse/issues/31686). [#31697](https://github.com/ClickHouse/ClickHouse/pull/31697) ([tavplubix](https://github.com/tavplubix)).
+* Fixed null pointer exception in `MATERIALIZE COLUMN`. [#31679](https://github.com/ClickHouse/ClickHouse/pull/31679) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* `RENAME TABLE` query worked incorrectly on attempt to rename an DDL dictionary in `Ordinary` database, it's fixed. [#31638](https://github.com/ClickHouse/ClickHouse/pull/31638) ([tavplubix](https://github.com/tavplubix)).
+* Implement `sparkbar` aggregate function as it was intended, see: [#26175](https://github.com/ClickHouse/ClickHouse/issues/26175)#issuecomment-960353867, [comment](https://github.com/ClickHouse/ClickHouse/issues/26175#issuecomment-961155065). [#31624](https://github.com/ClickHouse/ClickHouse/pull/31624) ([小路](https://github.com/nicelulu)).
+* Fix invalid generated JSON when only column names contain invalid UTF-8 sequences. [#31534](https://github.com/ClickHouse/ClickHouse/pull/31534) ([Kevin Michel](https://github.com/kmichel-aiven)).
+* Disable `partial_merge_join_left_table_buffer_bytes` before bug in this optimization is fixed. See [#31009](https://github.com/ClickHouse/ClickHouse/issues/31009)). Remove redundant option `partial_merge_join_optimizations`. [#31528](https://github.com/ClickHouse/ClickHouse/pull/31528) ([Vladimir C](https://github.com/vdimir)).
+* Fix progress for short `INSERT SELECT` queries. [#31510](https://github.com/ClickHouse/ClickHouse/pull/31510) ([Azat Khuzhin](https://github.com/azat)).
+* Fix wrong behavior with group by and positional arguments. Closes [#31280](https://github.com/ClickHouse/ClickHouse/issues/31280)#issuecomment-968696186. [#31420](https://github.com/ClickHouse/ClickHouse/pull/31420) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Resolve `nullptr` in STS credentials provider for S3. [#31409](https://github.com/ClickHouse/ClickHouse/pull/31409) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Remove `notLike` function from index analysis, because it was wrong. [#31169](https://github.com/ClickHouse/ClickHouse/pull/31169) ([sundyli](https://github.com/sundy-li)).
+* Fix bug in Keeper which can lead to inability to start when some coordination logs was lost and we have more fresh snapshot than our latest log. [#31150](https://github.com/ClickHouse/ClickHouse/pull/31150) ([alesapin](https://github.com/alesapin)).
+* Rewrite right distributed table in local join. solves [#25809](https://github.com/ClickHouse/ClickHouse/issues/25809). [#31105](https://github.com/ClickHouse/ClickHouse/pull/31105) ([abel-cheng](https://github.com/abel-cheng)).
+* Fix `Merge` table with aliases and where (it did not work before at all). Closes [#28802](https://github.com/ClickHouse/ClickHouse/issues/28802). [#31044](https://github.com/ClickHouse/ClickHouse/pull/31044) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix JSON_VALUE/JSON_QUERY with quoted identifiers. This allows to have spaces in json path. Closes [#30971](https://github.com/ClickHouse/ClickHouse/issues/30971). [#31003](https://github.com/ClickHouse/ClickHouse/pull/31003) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Using `formatRow` function with not row-oriented formats led to segfault. Don't allow to use this function with such formats (because it doesn't make sense). [#31001](https://github.com/ClickHouse/ClickHouse/pull/31001) ([Kruglov Pavel](https://github.com/Avogar)).
+* Fix bug which broke select queries if they happened after dropping materialized view. Found in [#30691](https://github.com/ClickHouse/ClickHouse/issues/30691). [#30997](https://github.com/ClickHouse/ClickHouse/pull/30997) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Skip `max_partition_size_to_drop check` in case of ATTACH PARTITION ... FROM and MOVE PARTITION ... [#30995](https://github.com/ClickHouse/ClickHouse/pull/30995) ([Amr Alaa](https://github.com/amralaa-MSFT)).
+* Fix some corner cases with `INTERSECT` and `EXCEPT` operators. Closes [#30803](https://github.com/ClickHouse/ClickHouse/issues/30803). [#30965](https://github.com/ClickHouse/ClickHouse/pull/30965) ([Kseniia Sumarokova](https://github.com/kssenii)).
+
+#### Build/Testing/Packaging Improvement
+
+* Fix incorrect filtering result on non-x86 builds. This closes [#31417](https://github.com/ClickHouse/ClickHouse/issues/31417). This closes [#31524](https://github.com/ClickHouse/ClickHouse/issues/31524). [#31574](https://github.com/ClickHouse/ClickHouse/pull/31574) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make ClickHouse build fully reproducible (byte identical on different machines). This closes [#22113](https://github.com/ClickHouse/ClickHouse/issues/22113). [#31899](https://github.com/ClickHouse/ClickHouse/pull/31899) ([alexey-milovidov](https://github.com/alexey-milovidov)). Remove filesystem path to the build directory from binaries to enable reproducible builds. This needed for [#22113](https://github.com/ClickHouse/ClickHouse/issues/22113). [#31838](https://github.com/ClickHouse/ClickHouse/pull/31838) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Use our own CMakeLists for `zlib-ng`, `cassandra`, `mariadb-connector-c` and `xz`, `re2`, `sentry`, `gsasl`, `arrow`, `protobuf`. This is needed for [#20151](https://github.com/ClickHouse/ClickHouse/issues/20151). Part of [#9226](https://github.com/ClickHouse/ClickHouse/issues/9226). A small step towards removal of annoying trash from the build system. [#30599](https://github.com/ClickHouse/ClickHouse/pull/30599) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Hermetic builds: use fixed version of libc and make sure that no source or binary files from the host OS are using during build. This closes [#27133](https://github.com/ClickHouse/ClickHouse/issues/27133). This closes [#21435](https://github.com/ClickHouse/ClickHouse/issues/21435). This closes [#30462](https://github.com/ClickHouse/ClickHouse/issues/30462). [#30011](https://github.com/ClickHouse/ClickHouse/pull/30011) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Adding function `getFuzzerData()` to easily fuzz particular functions. This closes [#23227](https://github.com/ClickHouse/ClickHouse/issues/23227). [#27526](https://github.com/ClickHouse/ClickHouse/pull/27526) ([Alexey Boykov](https://github.com/mathalex)).
+* More correct setting up capabilities inside Docker. [#31802](https://github.com/ClickHouse/ClickHouse/pull/31802) ([Constantine Peresypkin](https://github.com/pkit)).
+* Enable clang `-fstrict-vtable-pointers`, `-fwhole-program-vtables` compile options. [#20151](https://github.com/ClickHouse/ClickHouse/pull/20151) ([Maksim Kita](https://github.com/kitaisreal)).
+* Avoid downloading toolchain tarballs for cross-compiling for FreeBSD. [#31672](https://github.com/ClickHouse/ClickHouse/pull/31672) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Initial support for risc-v. See development/build-cross-riscv for quirks and build command that was tested. [#31309](https://github.com/ClickHouse/ClickHouse/pull/31309) ([Vladimir Smirnov](https://github.com/Civil)).
+* Support compile in arm machine with parameter "-DENABLE_TESTS=OFF". [#31007](https://github.com/ClickHouse/ClickHouse/pull/31007) ([zhanghuajie](https://github.com/zhanghuajieHIT)).
+
+
+### ClickHouse release v21.11, 2021-11-09
+
+#### Backward Incompatible Change
+
+* Change order of json_path and json arguments in SQL/JSON functions (to be consistent with the standard). Closes [#30449](https://github.com/ClickHouse/ClickHouse/issues/30449). [#30474](https://github.com/ClickHouse/ClickHouse/pull/30474) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Remove `MergeTree` table setting `write_final_mark`. It will be always `true`. [#30455](https://github.com/ClickHouse/ClickHouse/pull/30455) ([Kseniia Sumarokova](https://github.com/kssenii)). No actions required, all tables are compatible with the new version.
+* Function `bayesAB` is removed. Please help to return this function back, refreshed. This closes [#26233](https://github.com/ClickHouse/ClickHouse/issues/26233). [#29934](https://github.com/ClickHouse/ClickHouse/pull/29934) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* This is relevant only if you already started using the experimental `clickhouse-keeper` support. Now ClickHouse Keeper snapshots compressed with `ZSTD` codec by default instead of custom ClickHouse LZ4 block compression. This behavior can be turned off with `compress_snapshots_with_zstd_format` coordination setting (must be equal on all quorum replicas). Backward incompatibility is quite rare and may happen only when new node will send snapshot (happens in case of recovery) to the old node which is unable to read snapshots in ZSTD format. [#29417](https://github.com/ClickHouse/ClickHouse/pull/29417) ([alesapin](https://github.com/alesapin)).
+
+#### New Feature
+
+* New asynchronous INSERT mode allows to accumulate inserted data and store it in a single batch in background. On client it can be enabled by setting `async_insert` for `INSERT` queries with data inlined in query or in separate buffer (e.g. for `INSERT` queries via HTTP protocol). If `wait_for_async_insert` is true (by default) the client will wait until data will be flushed to table. On server-side it controlled by the settings `async_insert_threads`, `async_insert_max_data_size` and `async_insert_busy_timeout_ms`. Implements [#18282](https://github.com/ClickHouse/ClickHouse/issues/18282). [#27537](https://github.com/ClickHouse/ClickHouse/pull/27537) ([Anton Popov](https://github.com/CurtizJ)). [#20557](https://github.com/ClickHouse/ClickHouse/pull/20557) ([Ivan](https://github.com/abyss7)). Notes on performance: with asynchronous inserts you can do up to around 10 000 individual INSERT queries per second, so it is still recommended to insert in batches if you want to achieve performance up to millions inserted rows per second.
+* Add interactive mode for `clickhouse-local`. So, you can just run `clickhouse-local` to get a command line ClickHouse interface without connecting to a server and process data from files and external data sources. Also merge the code of `clickhouse-client` and `clickhouse-local` together. Closes [#7203](https://github.com/ClickHouse/ClickHouse/issues/7203). Closes [#25516](https://github.com/ClickHouse/ClickHouse/issues/25516). Closes [#22401](https://github.com/ClickHouse/ClickHouse/issues/22401). [#26231](https://github.com/ClickHouse/ClickHouse/pull/26231) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Added support for executable (scriptable) user defined functions. These are UDFs that can be written in any programming language. [#28803](https://github.com/ClickHouse/ClickHouse/pull/28803) ([Maksim Kita](https://github.com/kitaisreal)).
+* Allow predefined connections to external data sources. This allows to avoid specifying credentials or addresses while using external data sources, they can be referenced by names instead. Closes [#28367](https://github.com/ClickHouse/ClickHouse/issues/28367). [#28577](https://github.com/ClickHouse/ClickHouse/pull/28577) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Added `INFORMATION_SCHEMA` database with `SCHEMATA`, `TABLES`, `VIEWS` and `COLUMNS` views to the corresponding tables in `system` database. Closes [#9770](https://github.com/ClickHouse/ClickHouse/issues/9770). [#28691](https://github.com/ClickHouse/ClickHouse/pull/28691) ([tavplubix](https://github.com/tavplubix)).
+* Support `EXISTS (subquery)`. Closes [#6852](https://github.com/ClickHouse/ClickHouse/issues/6852). [#29731](https://github.com/ClickHouse/ClickHouse/pull/29731) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Session logging for audit. Logging all successful and failed login and logout events to a new `system.session_log` table. [#22415](https://github.com/ClickHouse/ClickHouse/pull/22415) ([Vasily Nemkov](https://github.com/Enmk)) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Support multidimensional cosine distance and euclidean distance functions; L1, L2, Lp, Linf distances and norms. Scalar product on tuples and various arithmetic operators on tuples. This fully closes [#4509](https://github.com/ClickHouse/ClickHouse/issues/4509) and even more. [#27933](https://github.com/ClickHouse/ClickHouse/pull/27933) ([Alexey Boykov](https://github.com/mathalex)).
+* Add support for compression and decompression for `INTO OUTFILE` and `FROM INFILE` (with autodetect or with additional optional parameter). [#27135](https://github.com/ClickHouse/ClickHouse/pull/27135) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
+* Add CORS (Cross Origin Resource Sharing) support with HTTP `OPTIONS` request. It means, now Grafana will work with serverless requests without a kludges. Closes [#18693](https://github.com/ClickHouse/ClickHouse/issues/18693). [#29155](https://github.com/ClickHouse/ClickHouse/pull/29155) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
+* Queries with JOIN ON now supports disjunctions (OR). [#21320](https://github.com/ClickHouse/ClickHouse/pull/21320) ([Ilya Golshtein](https://github.com/ilejn)).
+* Added function `tokens`. That allow to split string into tokens using non-alpha numeric ASCII characters as separators. [#29981](https://github.com/ClickHouse/ClickHouse/pull/29981) ([Maksim Kita](https://github.com/kitaisreal)). Added function `ngrams` to extract ngrams from text. Closes [#29699](https://github.com/ClickHouse/ClickHouse/issues/29699). [#29738](https://github.com/ClickHouse/ClickHouse/pull/29738) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add functions for Unicode normalization: `normalizeUTF8NFC`, `normalizeUTF8NFD`, `normalizeUTF8NFKC`, `normalizeUTF8NFKD` functions. [#28633](https://github.com/ClickHouse/ClickHouse/pull/28633) ([darkkeks](https://github.com/darkkeks)).
+* Streaming consumption of application log files in ClickHouse with `FileLog` table engine. It's like `Kafka` or `RabbitMQ` engine but for append-only and rotated logs in local filesystem. Closes [#6953](https://github.com/ClickHouse/ClickHouse/issues/6953). [#25969](https://github.com/ClickHouse/ClickHouse/pull/25969) ([flynn](https://github.com/ucasfl)) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add `CapnProto` output format, refactor `CapnProto` input format. [#29291](https://github.com/ClickHouse/ClickHouse/pull/29291) ([Kruglov Pavel](https://github.com/Avogar)).
+* Allow to write number in query as binary literal. Example `SELECT 0b001;`. [#29304](https://github.com/ClickHouse/ClickHouse/pull/29304) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added `hashed_array` dictionary type. It saves memory when using dictionaries with multiple attributes. Closes [#30236](https://github.com/ClickHouse/ClickHouse/issues/30236). [#30242](https://github.com/ClickHouse/ClickHouse/pull/30242) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added `JSONExtractKeys` function. [#30056](https://github.com/ClickHouse/ClickHouse/pull/30056) ([Vitaly](https://github.com/orloffv)).
+* Add a function `getOSKernelVersion` - it returns a string with OS kernel version. [#29755](https://github.com/ClickHouse/ClickHouse/pull/29755) ([Memo](https://github.com/Joeywzr)).
+* Added `MD4` and `SHA384` functions. MD4 is an obsolete and insecure hash function, it can be used only in rare cases when MD4 is already being used in some legacy system and you need to get exactly the same result. [#29602](https://github.com/ClickHouse/ClickHouse/pull/29602) ([Nikita Tikhomirov](https://github.com/NSTikhomirov)).
+* HSTS can be enabled for Clickhouse HTTP server by setting `hsts_max_age` in configuration file with a positive number. [#29516](https://github.com/ClickHouse/ClickHouse/pull/29516) ([凌涛](https://github.com/lingtaolf)).
+* Huawei OBS Storage support. Closes [#24294](https://github.com/ClickHouse/ClickHouse/issues/24294). [#29511](https://github.com/ClickHouse/ClickHouse/pull/29511) ([kevin wan](https://github.com/MaxWk)).
+* New function `mapContainsKeyLike` to get the map that key matches a simple regular expression. [#29471](https://github.com/ClickHouse/ClickHouse/pull/29471) ([凌涛](https://github.com/lingtaolf)). New function `mapExtractKeyLike` to get the map only kept elements matched specified pattern. [#30793](https://github.com/ClickHouse/ClickHouse/pull/30793) ([凌涛](https://github.com/lingtaolf)).
+* Implemented `ALTER TABLE x MODIFY COMMENT`. [#29264](https://github.com/ClickHouse/ClickHouse/pull/29264) ([Vasily Nemkov](https://github.com/Enmk)).
+* Adds H3 inspection functions that are missing from ClickHouse but are available via the H3 api: https://h3geo.org/docs/api/inspection. [#29209](https://github.com/ClickHouse/ClickHouse/pull/29209) ([Bharat Nallan](https://github.com/bharatnc)).
+* Allow non-replicated ALTER TABLE FETCH and ATTACH in Replicated databases. [#29202](https://github.com/ClickHouse/ClickHouse/pull/29202) ([Kevin Michel](https://github.com/kmichel-aiven)).
+* Added a setting `output_format_csv_null_representation`: This is the same as `output_format_tsv_null_representation` but is for CSV output. [#29123](https://github.com/ClickHouse/ClickHouse/pull/29123) ([PHO](https://github.com/depressed-pho)).
+* Added function `zookeeperSessionUptime()` which returns uptime of current ZooKeeper session in seconds. [#28983](https://github.com/ClickHouse/ClickHouse/pull/28983) ([tavplubix](https://github.com/tavplubix)).
+* Implements the `h3ToGeoBoundary` function. [#28952](https://github.com/ClickHouse/ClickHouse/pull/28952) ([Ivan Veselov](https://github.com/fuzzERot)).
+* Add aggregate function `exponentialMovingAverage` that can be used as window function. This closes [#27511](https://github.com/ClickHouse/ClickHouse/issues/27511). [#28914](https://github.com/ClickHouse/ClickHouse/pull/28914) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow to include subcolumns of table columns into `DESCRIBE` query result (can be enabled by setting `describe_include_subcolumns`). [#28905](https://github.com/ClickHouse/ClickHouse/pull/28905) ([Anton Popov](https://github.com/CurtizJ)).
+* `Executable`, `ExecutablePool` added option `send_chunk_header`. If this option is true then chunk rows_count with line break will be sent to client before chunk. [#28833](https://github.com/ClickHouse/ClickHouse/pull/28833) ([Maksim Kita](https://github.com/kitaisreal)).
+* `tokenbf_v1` and `ngram` support Map with key of String of FixedSring type. It enhance data skipping in query with map key filter. ```sql CREATE TABLE map_tokenbf ( row_id UInt32, map Map(String, String), INDEX map_tokenbf map TYPE ngrambf_v1(4,256,2,0) GRANULARITY 1 ) Engine=MergeTree() Order by id ``` With table above, the query `select * from map_tokebf where map['K']='V'` will skip the granule that doesn't contain key `A` . Of course, how many rows will skipped is depended on the `granularity` and `index_granularity` you set. [#28511](https://github.com/ClickHouse/ClickHouse/pull/28511) ([凌涛](https://github.com/lingtaolf)).
+* Send profile events from server to client. New packet type `ProfileEvents` was introduced. Closes [#26177](https://github.com/ClickHouse/ClickHouse/issues/26177). [#28364](https://github.com/ClickHouse/ClickHouse/pull/28364) ([Dmitry Novik](https://github.com/novikd)).
+* Bit shift operations for `FixedString` and `String` data types. This closes [#27763](https://github.com/ClickHouse/ClickHouse/issues/27763). [#28325](https://github.com/ClickHouse/ClickHouse/pull/28325) ([小路](https://github.com/nicelulu)).
+* Support adding / deleting tables to replication from PostgreSQL dynamically in database engine MaterializedPostgreSQL. Support alter for database settings. Closes [#27573](https://github.com/ClickHouse/ClickHouse/issues/27573). [#28301](https://github.com/ClickHouse/ClickHouse/pull/28301) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Added function accurateCastOrDefault(x, T). Closes [#21330](https://github.com/ClickHouse/ClickHouse/issues/21330). Authors @taiyang-li. [#23028](https://github.com/ClickHouse/ClickHouse/pull/23028) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add Function `toUUIDOrDefault`, `toUInt8/16/32/64/256OrDefault`, `toInt8/16/32/64/128/256OrDefault`, which enables user defining default value(not null) when string parsing is failed. [#21330](https://github.com/ClickHouse/ClickHouse/pull/21330) ([taiyang-li](https://github.com/taiyang-li)).
+
+#### Performance Improvement
+
+* Background merges can be preempted by each other and they are scheduled with appropriate priorities. Now long running merges won't prevent short merges to proceed. This is needed for a better scheduling and controlling of merges execution. It reduces the chances to get "too many parts" error. [#22381](https://github.com/ClickHouse/ClickHouse/issues/22381). [#25165](https://github.com/ClickHouse/ClickHouse/pull/25165) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)). Added an ability to execute more merges and mutations than the number of threads in background pool. Merges and mutations will be executed step by step according to their sizes (lower is more prioritized). The ratio of the number of tasks to threads to execute is controlled by a setting `background_merges_mutations_concurrency_ratio`, 2 by default. [#29140](https://github.com/ClickHouse/ClickHouse/pull/29140) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Allow to use asynchronous reads for remote filesystems. Lower the number of seeks while reading from remote filesystems. It improves performance tremendously and makes the experimental `web` and `s3` disks to work faster than EBS under certain conditions. [#29205](https://github.com/ClickHouse/ClickHouse/pull/29205) ([Kseniia Sumarokova](https://github.com/kssenii)). In the meantime, the `web` disk type (static dataset hosted on a web server) is graduated from being experimental to be production ready.
+* Queries with `INTO OUTFILE` in `clickhouse-client` will use multiple threads. Fix the issue with flickering progress-bar when using `INTO OUTFILE`. This closes [#30873](https://github.com/ClickHouse/ClickHouse/issues/30873). This closes [#30872](https://github.com/ClickHouse/ClickHouse/issues/30872). [#30886](https://github.com/ClickHouse/ClickHouse/pull/30886) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Reduce amount of redundant compressed data read from disk for some types `SELECT` queries (only for `MergeTree` engines family). [#30111](https://github.com/ClickHouse/ClickHouse/pull/30111) ([alesapin](https://github.com/alesapin)).
+* Remove some redundant `seek` calls while reading compressed blocks in MergeTree table engines family. [#29766](https://github.com/ClickHouse/ClickHouse/pull/29766) ([alesapin](https://github.com/alesapin)).
+* Make `url` table function to process multiple URLs in parallel. This closes [#29670](https://github.com/ClickHouse/ClickHouse/issues/29670) and closes [#29671](https://github.com/ClickHouse/ClickHouse/issues/29671). [#29673](https://github.com/ClickHouse/ClickHouse/pull/29673) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve performance of aggregation in order of primary key (with enabled setting `optimize_aggregation_in_order`). [#30266](https://github.com/ClickHouse/ClickHouse/pull/30266) ([Anton Popov](https://github.com/CurtizJ)).
+* Now clickhouse is using DNS cache while communicating with external S3. [#29999](https://github.com/ClickHouse/ClickHouse/pull/29999) ([alesapin](https://github.com/alesapin)).
+* Add support for pushdown of `IS NULL`/`IS NOT NULL` to external databases (i.e. MySQL). [#29463](https://github.com/ClickHouse/ClickHouse/pull/29463) ([Azat Khuzhin](https://github.com/azat)). Transform `isNull`/`isNotNull` to `IS NULL`/`IS NOT NULL` (for external dbs, i.e. MySQL). [#29446](https://github.com/ClickHouse/ClickHouse/pull/29446) ([Azat Khuzhin](https://github.com/azat)).
+* SELECT queries from Dictionary tables will use multiple threads. [#30500](https://github.com/ClickHouse/ClickHouse/pull/30500) ([Maksim Kita](https://github.com/kitaisreal)).
+* Improve performance for filtering (WHERE operation) of `Decimal` columns. [#30431](https://github.com/ClickHouse/ClickHouse/pull/30431) ([Jun Jin](https://github.com/vesslanjin)).
+* Remove branchy code in filter operation with a better implementation with popcnt/ctz which have better performance. [#29881](https://github.com/ClickHouse/ClickHouse/pull/29881) ([Jun Jin](https://github.com/vesslanjin)).
+* Improve filter bytemask generator (used for WHERE operator) function all in one with SSE/AVX2/AVX512 instructions. Note that by default ClickHouse is only using SSE, so it's only relevant for custom builds. [#30014](https://github.com/ClickHouse/ClickHouse/pull/30014) ([jasperzhu](https://github.com/jinjunzh)). [#30670](https://github.com/ClickHouse/ClickHouse/pull/30670) ([jasperzhu](https://github.com/jinjunzh)).
+* Improve the performance of SUM aggregate function of Nullable floating point numbers. [#28906](https://github.com/ClickHouse/ClickHouse/pull/28906) ([Raúl Marín](https://github.com/Algunenano)).
+* Speed up part loading process with multiple disks are in use. The idea is similar to https://github.com/ClickHouse/ClickHouse/pull/16423 . Prod env shows improvement: 24 min -> 16 min . [#28363](https://github.com/ClickHouse/ClickHouse/pull/28363) ([Amos Bird](https://github.com/amosbird)).
+* Reduce default settings for S3 multipart upload part size to lower memory usage. [#28679](https://github.com/ClickHouse/ClickHouse/pull/28679) ([ianton-ru](https://github.com/ianton-ru)).
+* Speed up `bitmapAnd` function. [#28332](https://github.com/ClickHouse/ClickHouse/pull/28332) ([dddounaiking](https://github.com/OodounaikingoO)).
+* Removed sub-optimal mutation notifications in `StorageMergeTree` when merges are still going. [#27552](https://github.com/ClickHouse/ClickHouse/pull/27552) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Attempt to improve performance of string comparison. [#28767](https://github.com/ClickHouse/ClickHouse/pull/28767) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Primary key index and partition filter can work in tuple. [#29281](https://github.com/ClickHouse/ClickHouse/pull/29281) ([凌涛](https://github.com/lingtaolf)).
+* If query has multiple quantile aggregate functions with the same arguments but different level parameter, they will be fused together and executed in one pass if the setting `optimize_syntax_fuse_functions` is enabled. [#26657](https://github.com/ClickHouse/ClickHouse/pull/26657) ([hexiaoting](https://github.com/hexiaoting)).
+* Now min-max aggregation over the first expression of primary key is optimized by projection. This is for [#329](https://github.com/ClickHouse/ClickHouse/issues/329). [#29918](https://github.com/ClickHouse/ClickHouse/pull/29918) ([Amos Bird](https://github.com/amosbird)).
+
+#### Experimental Feature
+
+* Add ability to change nodes configuration (in `.xml` file) for ClickHouse Keeper. [#30372](https://github.com/ClickHouse/ClickHouse/pull/30372) ([alesapin](https://github.com/alesapin)).
+* Add `sparkbar` aggregate function. This closes [#26175](https://github.com/ClickHouse/ClickHouse/issues/26175). [#27481](https://github.com/ClickHouse/ClickHouse/pull/27481) ([小路](https://github.com/nicelulu)). Note: there is one flaw in this function, the behaviour will be changed in future releases.
+
+#### Improvement
+
+* Allow user to change log levels without restart. [#29586](https://github.com/ClickHouse/ClickHouse/pull/29586) ([Nikolay Degterinsky](https://github.com/evillique)).
+* Multiple improvements for SQL UDF. Queries for manipulation of SQL User Defined Functions now support ON CLUSTER clause. Example `CREATE FUNCTION test_function ON CLUSTER 'cluster' AS x -> x + 1;`. Closes [#30666](https://github.com/ClickHouse/ClickHouse/issues/30666). [#30734](https://github.com/ClickHouse/ClickHouse/pull/30734) ([Maksim Kita](https://github.com/kitaisreal)). Support `CREATE OR REPLACE`, `CREATE IF NOT EXISTS` syntaxes. [#30454](https://github.com/ClickHouse/ClickHouse/pull/30454) ([Maksim Kita](https://github.com/kitaisreal)). Added DROP IF EXISTS support. Example `DROP FUNCTION IF EXISTS test_function`. [#30437](https://github.com/ClickHouse/ClickHouse/pull/30437) ([Maksim Kita](https://github.com/kitaisreal)). Support lambdas. Example `CREATE FUNCTION lambda_function AS x -> arrayMap(element -> element * 2, x);`. [#30435](https://github.com/ClickHouse/ClickHouse/pull/30435) ([Maksim Kita](https://github.com/kitaisreal)). Support SQL user defined functions for `clickhouse-local`. [#30179](https://github.com/ClickHouse/ClickHouse/pull/30179) ([Maksim Kita](https://github.com/kitaisreal)).
+* Enable per-query memory profiler (set to `memory_profiler_step` = 4MiB) globally. [#29455](https://github.com/ClickHouse/ClickHouse/pull/29455) ([Azat Khuzhin](https://github.com/azat)).
+* Added columns `data_compressed_bytes`, `data_uncompressed_bytes`, `marks_bytes` into `system.data_skipping_indices`. Added columns `secondary_indices_compressed_bytes`, `secondary_indices_uncompressed_bytes`, `secondary_indices_marks_bytes` into `system.parts`. Closes [#29697](https://github.com/ClickHouse/ClickHouse/issues/29697). [#29896](https://github.com/ClickHouse/ClickHouse/pull/29896) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add `table` alias to system.tables and `database` alias to system.databases [#29677](https://github.com/ClickHouse/ClickHouse/issues/29677). [#29882](https://github.com/ClickHouse/ClickHouse/pull/29882) ([kevin wan](https://github.com/MaxWk)).
+* Correctly resolve interdependencies between tables on server startup. Closes [#8004](https://github.com/ClickHouse/ClickHouse/issues/8004), closes [#15170](https://github.com/ClickHouse/ClickHouse/issues/15170). [#28373](https://github.com/ClickHouse/ClickHouse/pull/28373) ([tavplubix](https://github.com/tavplubix)).
+* Avoid error "Division by zero" when denominator is Nullable in functions `divide`, `intDiv` and `modulo`. Closes [#22621](https://github.com/ClickHouse/ClickHouse/issues/22621). [#28352](https://github.com/ClickHouse/ClickHouse/pull/28352) ([Kruglov Pavel](https://github.com/Avogar)).
+* Allow to parse values of `Date` data type in text formats as `YYYYMMDD` in addition to `YYYY-MM-DD`. This closes [#30870](https://github.com/ClickHouse/ClickHouse/issues/30870). [#30871](https://github.com/ClickHouse/ClickHouse/pull/30871) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Web UI: render bars in table cells. [#29792](https://github.com/ClickHouse/ClickHouse/pull/29792) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* User can now create dictionaries with comments: `CREATE DICTIONARY ... COMMENT 'vaue'` ... [#29899](https://github.com/ClickHouse/ClickHouse/pull/29899) ([Vasily Nemkov](https://github.com/Enmk)). Users now can set comments to database in `CREATE DATABASE` statement ... [#29429](https://github.com/ClickHouse/ClickHouse/pull/29429) ([Vasily Nemkov](https://github.com/Enmk)).
+* Introduce `compiled_expression_cache_elements_size` setting. If you will ever want to use this setting, you will already know what it does. [#30667](https://github.com/ClickHouse/ClickHouse/pull/30667) ([Maksim Kita](https://github.com/kitaisreal)).
+* clickhouse-format now supports option `--query`. In previous versions you have to pass the query to stdin. [#29325](https://github.com/ClickHouse/ClickHouse/pull/29325) ([凌涛](https://github.com/lingtaolf)).
+* Support `ALTER TABLE` for tables in `Memory` databases. Memory databases are used in `clickhouse-local`. [#30866](https://github.com/ClickHouse/ClickHouse/pull/30866) ([tavplubix](https://github.com/tavplubix)).
+* Arrays of all serializable types are now supported by `arrayStringConcat`. [#30840](https://github.com/ClickHouse/ClickHouse/pull/30840) ([Nickita Taranov](https://github.com/nickitat)).
+* ClickHouse now will account docker/cgroups limitations to get system memory amount. See [#25662](https://github.com/ClickHouse/ClickHouse/issues/25662). [#30574](https://github.com/ClickHouse/ClickHouse/pull/30574) ([Pavel Medvedev](https://github.com/pmed)).
+* Fetched table structure for PostgreSQL database is more reliable now. [#30477](https://github.com/ClickHouse/ClickHouse/pull/30477) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Full support of positional arguments in GROUP BY and ORDER BY. [#30433](https://github.com/ClickHouse/ClickHouse/pull/30433) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Allow extracting non-string element as string using JSONExtractString. This is for [pull/25452#issuecomment-927123287](https://github.com/ClickHouse/ClickHouse/pull/25452#issuecomment-927123287). [#30426](https://github.com/ClickHouse/ClickHouse/pull/30426) ([Amos Bird](https://github.com/amosbird)).
+* Added an ability to use FINAL clause in SELECT queries from `GraphiteMergeTree`. [#30360](https://github.com/ClickHouse/ClickHouse/pull/30360) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Minor improvements in replica cloning and enqueuing fetch for broken parts, that should avoid extremely rare hanging of `GET_PART` entries in replication queue. [#30346](https://github.com/ClickHouse/ClickHouse/pull/30346) ([tavplubix](https://github.com/tavplubix)).
+* Allow symlinks to files in `user_files` directory for file table function. [#30309](https://github.com/ClickHouse/ClickHouse/pull/30309) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fixed comparison of `Date32` with `Date`, `DateTime`, `DateTime64` and `String`. [#30219](https://github.com/ClickHouse/ClickHouse/pull/30219) ([liang.huang](https://github.com/lhuang09287750)).
+* Allow to remove `SAMPLE BY` expression from `MergeTree` tables (`ALTER TABLE <table> REMOVE SAMPLE BY`). [#30180](https://github.com/ClickHouse/ClickHouse/pull/30180) ([Anton Popov](https://github.com/CurtizJ)).
+* Now `Keeper` (as part of `clickhouse-server`) will start asynchronously if it can connect to some other node. [#30170](https://github.com/ClickHouse/ClickHouse/pull/30170) ([alesapin](https://github.com/alesapin)).
+* Now `clickhouse-client` supports native multi-line editing. [#30143](https://github.com/ClickHouse/ClickHouse/pull/30143) ([Amos Bird](https://github.com/amosbird)).
+* `polygon` dictionaries (reverse geocoding): added support for reading the dictionary content with SELECT query method if setting `store_polygon_key_column` = true. Closes [#30090](https://github.com/ClickHouse/ClickHouse/issues/30090). [#30142](https://github.com/ClickHouse/ClickHouse/pull/30142) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add ClickHouse logo to Play UI. [#29674](https://github.com/ClickHouse/ClickHouse/pull/29674) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Better exception message while reading column from Arrow-supported formats like `Arrow`, `ArrowStream`, `Parquet` and `ORC`. This closes [#29926](https://github.com/ClickHouse/ClickHouse/issues/29926). [#29927](https://github.com/ClickHouse/ClickHouse/pull/29927) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix data-race between flush and startup in `Buffer` tables. This can appear in tests. [#29930](https://github.com/ClickHouse/ClickHouse/pull/29930) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `lock-order-inversion` between `DROP TABLE` for `DatabaseMemory` and `LiveView`. Live View is an experimental feature. Memory database is used in clickhouse-local. [#29929](https://github.com/ClickHouse/ClickHouse/pull/29929) ([Azat Khuzhin](https://github.com/azat)).
+* Fix lock-order-inversion between periodic dictionary reload and config reload. [#29928](https://github.com/ClickHouse/ClickHouse/pull/29928) ([Azat Khuzhin](https://github.com/azat)).
+* Update zoneinfo files to 2021c. [#29925](https://github.com/ClickHouse/ClickHouse/pull/29925) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add ability to configure retries and delays between them for `clickhouse-copier`. [#29921](https://github.com/ClickHouse/ClickHouse/pull/29921) ([Azat Khuzhin](https://github.com/azat)).
+* Add `shutdown_wait_unfinished_queries` server setting to allowing waiting for running queries up to `shutdown_wait_unfinished` time. This is for [#24451](https://github.com/ClickHouse/ClickHouse/issues/24451). [#29914](https://github.com/ClickHouse/ClickHouse/pull/29914) ([Amos Bird](https://github.com/amosbird)).
+* Add ability to trace peak memory usage (with new trace_type in `system.trace_log` - `MemoryPeak`). [#29858](https://github.com/ClickHouse/ClickHouse/pull/29858) ([Azat Khuzhin](https://github.com/azat)).
+* PostgreSQL foreign tables: Added partitioned table prefix 'p' for the query for fetching replica identity index. [#29828](https://github.com/ClickHouse/ClickHouse/pull/29828) ([Shoh Jahon](https://github.com/Shohjahon)).
+* Apply `max_untracked_memory`/`memory_profiler_step`/`memory_profiler_sample_probability` during mutate/merge to profile memory usage during merges. [#29681](https://github.com/ClickHouse/ClickHouse/pull/29681) ([Azat Khuzhin](https://github.com/azat)).
+* Query obfuscator: `clickhouse-format --obfuscate` now works with more types of queries. [#29672](https://github.com/ClickHouse/ClickHouse/pull/29672) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the issue: `clickhouse-format --obfuscate` cannot process queries with embedded dictionaries (functions `regionTo...`). [#29667](https://github.com/ClickHouse/ClickHouse/pull/29667) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix incorrect Nullable processing of JSON functions. This fixes [#29615](https://github.com/ClickHouse/ClickHouse/issues/29615) . Mark as improvement because https://github.com/ClickHouse/ClickHouse/pull/28012 is not released. [#29659](https://github.com/ClickHouse/ClickHouse/pull/29659) ([Amos Bird](https://github.com/amosbird)).
+* Increase `listen_backlog` by default (to match default in newer linux kernel). [#29643](https://github.com/ClickHouse/ClickHouse/pull/29643) ([Azat Khuzhin](https://github.com/azat)).
+* Reload dictionaries, models, user defined executable functions if servers config `dictionaries_config`, `models_config`, `user_defined_executable_functions_config` changes. Closes [#28142](https://github.com/ClickHouse/ClickHouse/issues/28142). [#29529](https://github.com/ClickHouse/ClickHouse/pull/29529) ([Maksim Kita](https://github.com/kitaisreal)).
+* Get rid of pointless restriction on projection name. Now projection name can start with `tmp_`. [#29520](https://github.com/ClickHouse/ClickHouse/pull/29520) ([Amos Bird](https://github.com/amosbird)).
+* Fixed `There is no query or query context has expired` error in mutations with nested subqueries. Do not allow subqueries in mutation if table is replicated and `allow_nondeterministic_mutations` setting is disabled. [#29495](https://github.com/ClickHouse/ClickHouse/pull/29495) ([tavplubix](https://github.com/tavplubix)).
+* Apply config changes to `max_concurrent_queries` during runtime (no need to restart). [#29414](https://github.com/ClickHouse/ClickHouse/pull/29414) ([Raúl Marín](https://github.com/Algunenano)).
+* Added setting `use_skip_indexes`. [#29405](https://github.com/ClickHouse/ClickHouse/pull/29405) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add support for `FREEZE`ing in-memory parts (for backups). [#29376](https://github.com/ClickHouse/ClickHouse/pull/29376) ([Mo Xuan](https://github.com/mo-avatar)).
+* Pass through initial query_id for `clickhouse-benchmark` (previously if you run remote query via `clickhouse-benchmark`, queries on shards will not be linked to the initial query via `initial_query_id`). [#29364](https://github.com/ClickHouse/ClickHouse/pull/29364) ([Azat Khuzhin](https://github.com/azat)).
+* Skip indexes `tokenbf_v1` and `ngrambf_v1`: added support for `Array` data type with key of `String` of `FixedString` type. [#29280](https://github.com/ClickHouse/ClickHouse/pull/29280) ([Maksim Kita](https://github.com/kitaisreal)). Skip indexes `tokenbf_v1` and `ngrambf_v1` added support for `Map` data type with key of `String` of `FixedString` type. Author @lingtaolf. [#29220](https://github.com/ClickHouse/ClickHouse/pull/29220) ([Maksim Kita](https://github.com/kitaisreal)).
+* Function `has`: added support for `Map` data type. [#29267](https://github.com/ClickHouse/ClickHouse/pull/29267) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add `compress_logs` settings for clickhouse-keeper which allow to compress clickhouse-keeper logs (for replicated state machine) in `ZSTD` . Implements: [#26977](https://github.com/ClickHouse/ClickHouse/issues/26977). [#29223](https://github.com/ClickHouse/ClickHouse/pull/29223) ([alesapin](https://github.com/alesapin)).
+* Add a setting `external_table_strict_query` - it will force passing the whole WHERE expression in queries to foreign databases even if it is incompatible. [#29206](https://github.com/ClickHouse/ClickHouse/pull/29206) ([Azat Khuzhin](https://github.com/azat)).
+* Disable projections when `ARRAY JOIN` is used. In previous versions projection analysis may break aliases in array join. [#29139](https://github.com/ClickHouse/ClickHouse/pull/29139) ([Amos Bird](https://github.com/amosbird)).
+* Support more types in `MsgPack` input/output format. [#29077](https://github.com/ClickHouse/ClickHouse/pull/29077) ([Kruglov Pavel](https://github.com/Avogar)).
+* Allow to input and output `LowCardinality` columns in `ORC` input/output format. [#29062](https://github.com/ClickHouse/ClickHouse/pull/29062) ([Kruglov Pavel](https://github.com/Avogar)).
+* Select from `system.distributed_ddl_queue` might show incorrect values, it's fixed. [#29061](https://github.com/ClickHouse/ClickHouse/pull/29061) ([tavplubix](https://github.com/tavplubix)).
+* Correct behaviour with unknown methods for HTTP connection. Solves [#29050](https://github.com/ClickHouse/ClickHouse/issues/29050). [#29057](https://github.com/ClickHouse/ClickHouse/pull/29057) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
+* `clickhouse-keeper`: Fix bug in `clickhouse-keeper-converter` which can lead to some data loss while restoring from ZooKeeper logs (not snapshot). [#29030](https://github.com/ClickHouse/ClickHouse/pull/29030) ([小路](https://github.com/nicelulu)). Fix bug in `clickhouse-keeper-converter` which can lead to incorrect ZooKeeper log deserialization. [#29071](https://github.com/ClickHouse/ClickHouse/pull/29071) ([小路](https://github.com/nicelulu)).
+* Apply settings from `CREATE ... AS SELECT` queries (fixes: [#28810](https://github.com/ClickHouse/ClickHouse/issues/28810)). [#28962](https://github.com/ClickHouse/ClickHouse/pull/28962) ([Azat Khuzhin](https://github.com/azat)).
+* Respect default database setting for ALTER TABLE ... ON CLUSTER ... REPLACE/MOVE PARTITION FROM/TO ... [#28955](https://github.com/ClickHouse/ClickHouse/pull/28955) ([anneji-dev](https://github.com/anneji-dev)).
+* gRPC protocol: Allow change server-side compression from client. [#28953](https://github.com/ClickHouse/ClickHouse/pull/28953) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Skip "no data" exception when reading thermal sensors for asynchronous metrics. This closes [#28852](https://github.com/ClickHouse/ClickHouse/issues/28852). [#28882](https://github.com/ClickHouse/ClickHouse/pull/28882) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed logical race condition that might cause `Dictionary not found` error for existing dictionary in rare cases. [#28853](https://github.com/ClickHouse/ClickHouse/pull/28853) ([tavplubix](https://github.com/tavplubix)).
+* Relax nested function for If-combinator check (but forbid nested identical combinators). [#28828](https://github.com/ClickHouse/ClickHouse/pull/28828) ([Azat Khuzhin](https://github.com/azat)).
+* Fix possible uncaught exception during server termination. [#28761](https://github.com/ClickHouse/ClickHouse/pull/28761) ([Azat Khuzhin](https://github.com/azat)).
+* Forbid cleaning of tmp directories that can be used by an active mutation/merge if mutation/merge is extraordinarily long. [#28760](https://github.com/ClickHouse/ClickHouse/pull/28760) ([Azat Khuzhin](https://github.com/azat)).
+* Allow optimization `optimize_arithmetic_operations_in_aggregate_functions = 1` when alias is used. [#28746](https://github.com/ClickHouse/ClickHouse/pull/28746) ([Amos Bird](https://github.com/amosbird)).
+* Implement `detach_not_byte_identical_parts` setting for `ReplicatedMergeTree`, that will detach instead of remove not byte-identical parts (after mege/mutate). [#28708](https://github.com/ClickHouse/ClickHouse/pull/28708) ([Azat Khuzhin](https://github.com/azat)).
+* Implement `max_suspicious_broken_parts_bytes` setting for `MergeTree` (to limit total size of all broken parts, default is `1GiB`). [#28707](https://github.com/ClickHouse/ClickHouse/pull/28707) ([Azat Khuzhin](https://github.com/azat)).
+* Enable expanding macros in `RabbitMQ` table settings. [#28683](https://github.com/ClickHouse/ClickHouse/pull/28683) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Restore the possibility to read data of a table using the `Log` engine in multiple threads. [#28125](https://github.com/ClickHouse/ClickHouse/pull/28125) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix misbehavior of NULL column handling in JSON functions. This fixes [#27930](https://github.com/ClickHouse/ClickHouse/issues/27930). [#28012](https://github.com/ClickHouse/ClickHouse/pull/28012) ([Amos Bird](https://github.com/amosbird)).
+* Allow to set the size of Mark/Uncompressed cache for skip indices separately from columns. [#27961](https://github.com/ClickHouse/ClickHouse/pull/27961) ([Amos Bird](https://github.com/amosbird)).
+* Allow to mix JOIN with `USING` with other JOIN types. [#23881](https://github.com/ClickHouse/ClickHouse/pull/23881) ([darkkeks](https://github.com/darkkeks)).
+* Update aws-sdk submodule for throttling in Yandex Cloud S3. [#30646](https://github.com/ClickHouse/ClickHouse/pull/30646) ([ianton-ru](https://github.com/ianton-ru)).
+* Fix releasing query ID and session ID at the end of query processing while handing gRPC call. [#29954](https://github.com/ClickHouse/ClickHouse/pull/29954) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix shutdown of `AccessControlManager` to fix flaky test. [#29951](https://github.com/ClickHouse/ClickHouse/pull/29951) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix failed assertion in reading from `HDFS`. Update libhdfs3 library to be able to run in tests in debug. Closes [#29251](https://github.com/ClickHouse/ClickHouse/issues/29251). Closes [#27814](https://github.com/ClickHouse/ClickHouse/issues/27814). [#29276](https://github.com/ClickHouse/ClickHouse/pull/29276) ([Kseniia Sumarokova](https://github.com/kssenii)).
+
+
+#### Build/Testing/Packaging Improvement
+
+* Add support for FreeBSD builds for Aarch64 machines. [#29952](https://github.com/ClickHouse/ClickHouse/pull/29952) ([MikaelUrankar](https://github.com/MikaelUrankar)).
+* Recursive submodules are no longer needed for ClickHouse. [#30315](https://github.com/ClickHouse/ClickHouse/pull/30315) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* ClickHouse can be statically built with Musl. This is added as experiment, it does not support building `odbc-bridge`, `library-bridge`, integration with CatBoost and some libraries. [#30248](https://github.com/ClickHouse/ClickHouse/pull/30248) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Enable `Protobuf`, `Arrow`, `ORC`, `Parquet` for `AArch64` and `Darwin` (macOS) builds. This closes [#29248](https://github.com/ClickHouse/ClickHouse/issues/29248). This closes [#28018](https://github.com/ClickHouse/ClickHouse/issues/28018). [#30015](https://github.com/ClickHouse/ClickHouse/pull/30015) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add cross-build for PowerPC (powerpc64le). This closes [#9589](https://github.com/ClickHouse/ClickHouse/issues/9589). Enable support for interaction with MySQL for AArch64 and PowerPC. This closes [#26301](https://github.com/ClickHouse/ClickHouse/issues/26301). [#30010](https://github.com/ClickHouse/ClickHouse/pull/30010) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Leave only required files in cross-compile toolchains. Include them as submodules (earlier they were downloaded as tarballs). [#29974](https://github.com/ClickHouse/ClickHouse/pull/29974) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Implemented structure-aware fuzzing approach in ClickHouse for select statement parser. [#30012](https://github.com/ClickHouse/ClickHouse/pull/30012) ([Paul](https://github.com/PaulCher)).
+* Turning on experimental constexpr expressions evaluator for clang to speed up template code compilation. [#29668](https://github.com/ClickHouse/ClickHouse/pull/29668) ([myrrc](https://github.com/myrrc)).
+* Add ability to compile using newer version fo glibc without using new symbols. [#29594](https://github.com/ClickHouse/ClickHouse/pull/29594) ([Azat Khuzhin](https://github.com/azat)).
+* Reduce Debug build binary size by clang optimization option. [#28736](https://github.com/ClickHouse/ClickHouse/pull/28736) ([flynn](https://github.com/ucasfl)).
+* Now all images for CI will be placed in the separate dockerhub repo. [#28656](https://github.com/ClickHouse/ClickHouse/pull/28656) ([alesapin](https://github.com/alesapin)).
+* Improve support for build with clang-13. [#28046](https://github.com/ClickHouse/ClickHouse/pull/28046) ([Sergei Semin](https://github.com/syominsergey)).
+* Add ability to print raw profile events to `clickhouse-client` (This can be useful for debugging and for testing). [#30064](https://github.com/ClickHouse/ClickHouse/pull/30064) ([Azat Khuzhin](https://github.com/azat)).
+* Add time dependency for clickhouse-server unit (systemd and sysvinit init). [#28891](https://github.com/ClickHouse/ClickHouse/pull/28891) ([Azat Khuzhin](https://github.com/azat)).
+* Reload stacktrace cache when symbol is reloaded. [#28137](https://github.com/ClickHouse/ClickHouse/pull/28137) ([Amos Bird](https://github.com/amosbird)).
+
+#### Bug Fix
+
+* Functions for case-insensitive search in UTF-8 strings like `positionCaseInsensitiveUTF8` and `countSubstringsCaseInsensitiveUTF8` might find substrings that actually does not match in very rare cases, it's fixed. [#30663](https://github.com/ClickHouse/ClickHouse/pull/30663) ([tavplubix](https://github.com/tavplubix)).
+* Fix reading from empty file on encrypted disk. [#30494](https://github.com/ClickHouse/ClickHouse/pull/30494) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix transformation of disjunctions chain to `IN` (controlled by settings `optimize_min_equality_disjunction_chain_length`) in distributed queries with settings `legacy_column_name_of_tuple_literal = 0`. [#28658](https://github.com/ClickHouse/ClickHouse/pull/28658) ([Anton Popov](https://github.com/CurtizJ)).
+* Allow using a materialized column as the sharding key in a distributed table even if `insert_allow_materialized_columns=0`:. [#28637](https://github.com/ClickHouse/ClickHouse/pull/28637) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix `ORDER BY ... WITH FILL` with set `TO` and `FROM` and no rows in result set. [#30888](https://github.com/ClickHouse/ClickHouse/pull/30888) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix set index not used in AND/OR expressions when there are more than two operands. This fixes [#30416](https://github.com/ClickHouse/ClickHouse/issues/30416) . [#30887](https://github.com/ClickHouse/ClickHouse/pull/30887) ([Amos Bird](https://github.com/amosbird)).
+* Fix crash when projection with hashing function is materialized. This fixes [#30861](https://github.com/ClickHouse/ClickHouse/issues/30861) . The issue is similar to https://github.com/ClickHouse/ClickHouse/pull/28560 which is a lack of proper understanding of the invariant of header's emptyness. [#30877](https://github.com/ClickHouse/ClickHouse/pull/30877) ([Amos Bird](https://github.com/amosbird)).
+* Fixed ambiguity when extracting auxiliary ZooKeeper name from ZooKeeper path in `ReplicatedMergeTree`. Previously server might fail to start with `Unknown auxiliary ZooKeeper name` if ZooKeeper path contains a colon. Fixes [#29052](https://github.com/ClickHouse/ClickHouse/issues/29052). Also it was allowed to specify ZooKeeper path that does not start with slash, but now it's deprecated and creation of new tables with such path is not allowed. Slashes and colons in auxiliary ZooKeeper names are not allowed too. [#30822](https://github.com/ClickHouse/ClickHouse/pull/30822) ([tavplubix](https://github.com/tavplubix)).
+* Clean temporary directory when localBackup failed by some reason. [#30797](https://github.com/ClickHouse/ClickHouse/pull/30797) ([ianton-ru](https://github.com/ianton-ru)).
+* Fixed a race condition between `REPLACE/MOVE PARTITION` and background merge in non-replicated `MergeTree` that might cause a part of moved/replaced data to remain in partition. Fixes [#29327](https://github.com/ClickHouse/ClickHouse/issues/29327). [#30717](https://github.com/ClickHouse/ClickHouse/pull/30717) ([tavplubix](https://github.com/tavplubix)).
+* Fix PREWHERE with WHERE in case of always true PREWHERE. [#30668](https://github.com/ClickHouse/ClickHouse/pull/30668) ([Azat Khuzhin](https://github.com/azat)).
+* Limit push down optimization could cause a error `Cannot find column`. Fixes [#30438](https://github.com/ClickHouse/ClickHouse/issues/30438). [#30562](https://github.com/ClickHouse/ClickHouse/pull/30562) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Add missing parenthesis for `isNotNull`/`isNull` rewrites to `IS [NOT] NULL` (fixes queries that has something like `isNotNull(1)+isNotNull(2)`). [#30520](https://github.com/ClickHouse/ClickHouse/pull/30520) ([Azat Khuzhin](https://github.com/azat)).
+* Fix deadlock on ALTER with scalar subquery to the same table, close [#30461](https://github.com/ClickHouse/ClickHouse/issues/30461). [#30492](https://github.com/ClickHouse/ClickHouse/pull/30492) ([Vladimir C](https://github.com/vdimir)).
+* Fixed segfault which might happen if session expired during execution of REPLACE PARTITION. [#30432](https://github.com/ClickHouse/ClickHouse/pull/30432) ([tavplubix](https://github.com/tavplubix)).
+* Queries with condition like `IN (subquery)` could return incorrect result in case if aggregate projection applied. Fixed creation of sets for projections. [#30310](https://github.com/ClickHouse/ClickHouse/pull/30310) ([Amos Bird](https://github.com/amosbird)).
+* Fix column alias resolution of JOIN queries when projection is enabled. This fixes [#30146](https://github.com/ClickHouse/ClickHouse/issues/30146). [#30293](https://github.com/ClickHouse/ClickHouse/pull/30293) ([Amos Bird](https://github.com/amosbird)).
+* Fix some deficiency in `replaceRegexpAll` function. [#30292](https://github.com/ClickHouse/ClickHouse/pull/30292) ([Memo](https://github.com/Joeywzr)).
+* Fix ComplexKeyHashedDictionary, ComplexKeySparseHashedDictionary parsing `preallocate` option from layout config. [#30246](https://github.com/ClickHouse/ClickHouse/pull/30246) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix `[I]LIKE` function. Closes [#28661](https://github.com/ClickHouse/ClickHouse/issues/28661). [#30244](https://github.com/ClickHouse/ClickHouse/pull/30244) ([Nikolay Degterinsky](https://github.com/evillique)).
+* Fix crash with shortcircuit and lowcardinality in multiIf. [#30243](https://github.com/ClickHouse/ClickHouse/pull/30243) ([Raúl Marín](https://github.com/Algunenano)).
+* FlatDictionary, HashedDictionary fix bytes_allocated calculation for nullable attributes. [#30238](https://github.com/ClickHouse/ClickHouse/pull/30238) ([Maksim Kita](https://github.com/kitaisreal)).
+* Allow identifiers starting with numbers in multiple joins. [#30230](https://github.com/ClickHouse/ClickHouse/pull/30230) ([Vladimir C](https://github.com/vdimir)).
+* Fix reading from `MergeTree` with `max_read_buffer_size = 0` (when the user wants to shoot himself in the foot) (can lead to exceptions `Can't adjust last granule`, `LOGICAL_ERROR`, or even data loss). [#30192](https://github.com/ClickHouse/ClickHouse/pull/30192) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `pread_fake_async`/`pread_threadpool` with `min_bytes_to_use_direct_io`. [#30191](https://github.com/ClickHouse/ClickHouse/pull/30191) ([Azat Khuzhin](https://github.com/azat)).
+* Fix INSERT SELECT incorrectly fills MATERIALIZED column based of Nullable column. [#30189](https://github.com/ClickHouse/ClickHouse/pull/30189) ([Azat Khuzhin](https://github.com/azat)).
+* Support nullable arguments in function `initializeAggregation`. [#30177](https://github.com/ClickHouse/ClickHouse/pull/30177) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix error `Port is already connected` for queries with `GLOBAL IN` and `WITH TOTALS`. Only for 21.9 and 21.10. [#30086](https://github.com/ClickHouse/ClickHouse/pull/30086) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix race between MOVE PARTITION and merges/mutations for MergeTree. [#30074](https://github.com/ClickHouse/ClickHouse/pull/30074) ([Azat Khuzhin](https://github.com/azat)).
+* Dropped `Memory` database might reappear after server restart, it's fixed ([#29795](https://github.com/ClickHouse/ClickHouse/issues/29795)). Also added `force_remove_data_recursively_on_drop` setting as a workaround for `Directory not empty` error when dropping `Ordinary` database (because it's not possible to remove data leftovers manually in cloud environment). [#30054](https://github.com/ClickHouse/ClickHouse/pull/30054) ([tavplubix](https://github.com/tavplubix)).
+* Fix crash of sample by `tuple()`, closes [#30004](https://github.com/ClickHouse/ClickHouse/issues/30004). [#30016](https://github.com/ClickHouse/ClickHouse/pull/30016) ([flynn](https://github.com/ucasfl)).
+* try to close issue: [#29965](https://github.com/ClickHouse/ClickHouse/issues/29965). [#29976](https://github.com/ClickHouse/ClickHouse/pull/29976) ([hexiaoting](https://github.com/hexiaoting)).
+* Fix possible data-race between `FileChecker` and `StorageLog`/`StorageStripeLog`. [#29959](https://github.com/ClickHouse/ClickHouse/pull/29959) ([Azat Khuzhin](https://github.com/azat)).
+* Fix data-race between `LogSink::writeMarks()` and `LogSource` in `StorageLog`. [#29946](https://github.com/ClickHouse/ClickHouse/pull/29946) ([Azat Khuzhin](https://github.com/azat)).
+* Fix potential resource leak of the concurrent query limit of merge tree tables introduced in https://github.com/ClickHouse/ClickHouse/pull/19544. [#29879](https://github.com/ClickHouse/ClickHouse/pull/29879) ([Amos Bird](https://github.com/amosbird)).
+* Fix system tables recreation check (fails to detect changes in enum values). [#29857](https://github.com/ClickHouse/ClickHouse/pull/29857) ([Azat Khuzhin](https://github.com/azat)).
+* MaterializedMySQL: Fix an issue where if the connection to MySQL was lost, only parts of a transaction could be processed. [#29837](https://github.com/ClickHouse/ClickHouse/pull/29837) ([Håvard Kvålen](https://github.com/havardk)).
+* Avoid `Timeout exceeded: elapsed 18446744073.709553 seconds` error that might happen in extremely rare cases, presumably due to some bug in kernel. Fixes [#29154](https://github.com/ClickHouse/ClickHouse/issues/29154). [#29811](https://github.com/ClickHouse/ClickHouse/pull/29811) ([tavplubix](https://github.com/tavplubix)).
+* Fix bad cast in `ATTACH TABLE ... FROM 'path'` query when non-string literal is used instead of path. It may lead to reading of uninitialized memory. [#29790](https://github.com/ClickHouse/ClickHouse/pull/29790) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix concurrent access to `LowCardinality` during `GROUP BY` (in combination with `Buffer` tables it may lead to troubles). [#29782](https://github.com/ClickHouse/ClickHouse/pull/29782) ([Azat Khuzhin](https://github.com/azat)).
+* Fix incorrect `GROUP BY` (multiple rows with the same keys in result) in case of distributed query when shards had mixed versions `<= 21.3` and `>= 21.4`, `GROUP BY` key had several columns all with fixed size, and two-level aggregation was activated (see `group_by_two_level_threshold` and `group_by_two_level_threshold_bytes`). Fixes [#29580](https://github.com/ClickHouse/ClickHouse/issues/29580). [#29735](https://github.com/ClickHouse/ClickHouse/pull/29735) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed incorrect behaviour of setting `materialized_postgresql_tables_list` at server restart. Found in [#28529](https://github.com/ClickHouse/ClickHouse/issues/28529). [#29686](https://github.com/ClickHouse/ClickHouse/pull/29686) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Condition in filter predicate could be lost after push-down optimisation. [#29625](https://github.com/ClickHouse/ClickHouse/pull/29625) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix JIT expression compilation with aliases and short-circuit expression evaluation. Closes [#29403](https://github.com/ClickHouse/ClickHouse/issues/29403). [#29574](https://github.com/ClickHouse/ClickHouse/pull/29574) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix rare segfault in `ALTER MODIFY` query when using incorrect table identifier in `DEFAULT` expression like `x.y.z...` Fixes [#29184](https://github.com/ClickHouse/ClickHouse/issues/29184). [#29573](https://github.com/ClickHouse/ClickHouse/pull/29573) ([alesapin](https://github.com/alesapin)).
+* Fix nullptr deference for `GROUP BY WITH TOTALS HAVING` (when the column from `HAVING` wasn't selected). [#29553](https://github.com/ClickHouse/ClickHouse/pull/29553) ([Azat Khuzhin](https://github.com/azat)).
+* Avoid deadlocks when reading and writting on Join table engine tables at the same time. [#29544](https://github.com/ClickHouse/ClickHouse/pull/29544) ([Raúl Marín](https://github.com/Algunenano)).
+* Fix bug in check `pathStartsWith` becuase there was bug with the usage of `std::mismatch`: ` The behavior is undefined if the second range is shorter than the first range.`. [#29531](https://github.com/ClickHouse/ClickHouse/pull/29531) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* In ODBC bridge add retries for error Invalid cursor state. It is a retriable error. Closes [#29473](https://github.com/ClickHouse/ClickHouse/issues/29473). [#29518](https://github.com/ClickHouse/ClickHouse/pull/29518) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fixed incorrect table name parsing on loading of `Lazy` database. Fixes [#29456](https://github.com/ClickHouse/ClickHouse/issues/29456). [#29476](https://github.com/ClickHouse/ClickHouse/pull/29476) ([tavplubix](https://github.com/tavplubix)).
+* Fix possible `Block structure mismatch` for subqueries with pushed-down `HAVING` predicate. Fixes [#29010](https://github.com/ClickHouse/ClickHouse/issues/29010). [#29475](https://github.com/ClickHouse/ClickHouse/pull/29475) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix Logical error `Cannot capture columns` in functions greatest/least. Closes [#29334](https://github.com/ClickHouse/ClickHouse/issues/29334). [#29454](https://github.com/ClickHouse/ClickHouse/pull/29454) ([Kruglov Pavel](https://github.com/Avogar)).
+* RocksDB table engine: fix race condition during multiple DB opening (and get back some tests that triggers the problem on CI). [#29393](https://github.com/ClickHouse/ClickHouse/pull/29393) ([Azat Khuzhin](https://github.com/azat)).
+* Fix replicated access storage not shutting down cleanly when misconfigured. [#29388](https://github.com/ClickHouse/ClickHouse/pull/29388) ([Kevin Michel](https://github.com/kmichel-aiven)).
+* Remove window function `nth_value` as it is not memory-safe. This closes [#29347](https://github.com/ClickHouse/ClickHouse/issues/29347). [#29348](https://github.com/ClickHouse/ClickHouse/pull/29348) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix vertical merges of projection parts. This fixes [#29253](https://github.com/ClickHouse/ClickHouse/issues/29253) . This PR also fixes several projection merge/mutation issues introduced in https://github.com/ClickHouse/ClickHouse/pull/25165. [#29337](https://github.com/ClickHouse/ClickHouse/pull/29337) ([Amos Bird](https://github.com/amosbird)).
+* Fix hanging DDL queries on Replicated database while adding a new replica. [#29328](https://github.com/ClickHouse/ClickHouse/pull/29328) ([Kevin Michel](https://github.com/kmichel-aiven)).
+* Fix connection timeouts (`send_timeout`/`receive_timeout`). [#29282](https://github.com/ClickHouse/ClickHouse/pull/29282) ([Azat Khuzhin](https://github.com/azat)).
+* Fix possible `Table columns structure in ZooKeeper is different from local table structure` exception while recreating or creating new replicas of `ReplicatedMergeTree`, when one of table columns have default expressions with case-insensitive functions. [#29266](https://github.com/ClickHouse/ClickHouse/pull/29266) ([Anton Popov](https://github.com/CurtizJ)).
+* Send normal `Database doesn't exist error` (`UNKNOWN_DATABASE`) to the client (via TCP) instead of `Attempt to read after eof` (`ATTEMPT_TO_READ_AFTER_EOF`). [#29229](https://github.com/ClickHouse/ClickHouse/pull/29229) ([Azat Khuzhin](https://github.com/azat)).
+* Fix segfault while inserting into column with type LowCardinality(Nullable) in Avro input format. [#29132](https://github.com/ClickHouse/ClickHouse/pull/29132) ([Kruglov Pavel](https://github.com/Avogar)).
+* Do not allow to reuse previous credentials in case of inter-server secret (Before INSERT via Buffer/Kafka to Distributed table with interserver secret configured for that cluster, may re-use previously set user for that connection). [#29060](https://github.com/ClickHouse/ClickHouse/pull/29060) ([Azat Khuzhin](https://github.com/azat)).
+* Handle `any_join_distinct_right_table_keys` when join with dictionary, close [#29007](https://github.com/ClickHouse/ClickHouse/issues/29007). [#29014](https://github.com/ClickHouse/ClickHouse/pull/29014) ([Vladimir C](https://github.com/vdimir)).
+* Fix "Not found column ... in block" error, when join on alias column, close [#26980](https://github.com/ClickHouse/ClickHouse/issues/26980). [#29008](https://github.com/ClickHouse/ClickHouse/pull/29008) ([Vladimir C](https://github.com/vdimir)).
+* Fix the number of threads used in `GLOBAL IN` subquery (it was executed in single threads since [#19414](https://github.com/ClickHouse/ClickHouse/issues/19414) bugfix). [#28997](https://github.com/ClickHouse/ClickHouse/pull/28997) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bad optimizations of ORDER BY if it contains WITH FILL. This closes [#28908](https://github.com/ClickHouse/ClickHouse/issues/28908). This closes [#26049](https://github.com/ClickHouse/ClickHouse/issues/26049). [#28910](https://github.com/ClickHouse/ClickHouse/pull/28910) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix higher-order array functions (`SIGSEGV` for `arrayCompact`/`ILLEGAL_COLUMN` for `arrayDifference`/`arrayCumSumNonNegative`) with consts. [#28904](https://github.com/ClickHouse/ClickHouse/pull/28904) ([Azat Khuzhin](https://github.com/azat)).
+* Fix waiting for mutation with `mutations_sync=2`. [#28889](https://github.com/ClickHouse/ClickHouse/pull/28889) ([Azat Khuzhin](https://github.com/azat)).
+* Fix queries to external databases (i.e. MySQL) with multiple columns in IN ( i.e. `(k,v) IN ((1, 2))` ). [#28888](https://github.com/ClickHouse/ClickHouse/pull/28888) ([Azat Khuzhin](https://github.com/azat)).
+* Fix bug with `LowCardinality` in short-curcuit function evaluation. Closes [#28884](https://github.com/ClickHouse/ClickHouse/issues/28884). [#28887](https://github.com/ClickHouse/ClickHouse/pull/28887) ([Kruglov Pavel](https://github.com/Avogar)).
+* Fix reading of subcolumns from compact parts. [#28873](https://github.com/ClickHouse/ClickHouse/pull/28873) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed a race condition between `DROP PART` and `REPLACE/MOVE PARTITION` that might cause replicas to diverge in rare cases. [#28864](https://github.com/ClickHouse/ClickHouse/pull/28864) ([tavplubix](https://github.com/tavplubix)).
+* Fix expressions compilation with short circuit evaluation. [#28821](https://github.com/ClickHouse/ClickHouse/pull/28821) ([Azat Khuzhin](https://github.com/azat)).
+* Fix extremely rare case when ReplicatedMergeTree replicas can diverge after hard reboot of all replicas. The error looks like `Part ... intersects (previous|next) part ...`. [#28817](https://github.com/ClickHouse/ClickHouse/pull/28817) ([alesapin](https://github.com/alesapin)).
+* Better check for connection usability and also catch any exception in `RabbitMQ` shutdown just in case. [#28797](https://github.com/ClickHouse/ClickHouse/pull/28797) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix benign race condition in ReplicatedMergeTreeQueue. Shouldn't be visible for user, but can lead to subtle bugs. [#28734](https://github.com/ClickHouse/ClickHouse/pull/28734) ([alesapin](https://github.com/alesapin)).
+* Fix possible crash for `SELECT` with partially created aggregate projection in case of exception. [#28700](https://github.com/ClickHouse/ClickHouse/pull/28700) ([Amos Bird](https://github.com/amosbird)).
+* Fix the coredump in the creation of distributed tables, when the parameters passed in are wrong. [#28686](https://github.com/ClickHouse/ClickHouse/pull/28686) ([Zhiyong Wang](https://github.com/ljcui)).
+* Add Settings.Names, Settings.Values aliases for system.processes table. [#28685](https://github.com/ClickHouse/ClickHouse/pull/28685) ([Vitaly](https://github.com/orloffv)).
+* Support for S2 Geometry library: Fix the number of arguments required by `s2RectAdd` and `s2RectContains` functions. [#28663](https://github.com/ClickHouse/ClickHouse/pull/28663) ([Bharat Nallan](https://github.com/bharatnc)).
+* Fix invalid constant type conversion when Nullable or LowCardinality primary key is used. [#28636](https://github.com/ClickHouse/ClickHouse/pull/28636) ([Amos Bird](https://github.com/amosbird)).
+* Fix "Column is not under aggregate function and not in GROUP BY" with PREWHERE (Fixes: [#28461](https://github.com/ClickHouse/ClickHouse/issues/28461)). [#28502](https://github.com/ClickHouse/ClickHouse/pull/28502) ([Azat Khuzhin](https://github.com/azat)).
+
+
+### ClickHouse release v21.10, 2021-10-16
+
+#### Backward Incompatible Change
+
+* Now the following MergeTree table-level settings: `replicated_max_parallel_sends`, `replicated_max_parallel_sends_for_table`, `replicated_max_parallel_fetches`, `replicated_max_parallel_fetches_for_table` do nothing. They never worked well and were replaced with `max_replicated_fetches_network_bandwidth`, `max_replicated_sends_network_bandwidth` and `background_fetches_pool_size`. [#28404](https://github.com/ClickHouse/ClickHouse/pull/28404) ([alesapin](https://github.com/alesapin)).
+
+#### New Feature
+
+* Add feature for creating user-defined functions (UDF) as lambda expressions. Syntax `CREATE FUNCTION {function_name} as ({parameters}) -> {function core}`. Example `CREATE FUNCTION plus_one as (a) -> a + 1`. Authors @Realist007. [#27796](https://github.com/ClickHouse/ClickHouse/pull/27796) ([Maksim Kita](https://github.com/kitaisreal)) [#23978](https://github.com/ClickHouse/ClickHouse/pull/23978) ([Realist007](https://github.com/Realist007)).
+* Added `Executable` storage engine and `executable` table function. It enables data processing with external scripts in streaming fashion. [#28102](https://github.com/ClickHouse/ClickHouse/pull/28102) ([Maksim Kita](https://github.com/kitaisreal)) ([ruct](https://github.com/ruct)).
+* Added `ExecutablePool` storage engine. Similar to `Executable` but it's using a pool of long running processes. [#28518](https://github.com/ClickHouse/ClickHouse/pull/28518) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add `ALTER TABLE ... MATERIALIZE COLUMN` query. [#27038](https://github.com/ClickHouse/ClickHouse/pull/27038) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Support for partitioned write into `s3` table function. [#23051](https://github.com/ClickHouse/ClickHouse/pull/23051) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Support `lz4` compression format (in addition to `gz`, `bz2`, `xz`, `zstd`) for data import / export. [#25310](https://github.com/ClickHouse/ClickHouse/pull/25310) ([Bharat Nallan](https://github.com/bharatnc)).
+* Allow positional arguments under setting `enable_positional_arguments`. Closes [#2592](https://github.com/ClickHouse/ClickHouse/issues/2592). [#27530](https://github.com/ClickHouse/ClickHouse/pull/27530) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Accept user settings related to file formats in `SETTINGS` clause in `CREATE` query for s3 tables. This closes [#27580](https://github.com/ClickHouse/ClickHouse/issues/27580). [#28037](https://github.com/ClickHouse/ClickHouse/pull/28037) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Allow SSL connection for `RabbitMQ` engine. [#28365](https://github.com/ClickHouse/ClickHouse/pull/28365) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add `getServerPort` function to allow getting server port. When the port is not used by the server, throw an exception. [#27900](https://github.com/ClickHouse/ClickHouse/pull/27900) ([Amos Bird](https://github.com/amosbird)).
+* Add conversion functions between "snowflake id" and `DateTime`, `DateTime64`. See [#27058](https://github.com/ClickHouse/ClickHouse/issues/27058). [#27704](https://github.com/ClickHouse/ClickHouse/pull/27704) ([jasine](https://github.com/jasine)).
+* Add function `SHA512`. [#27830](https://github.com/ClickHouse/ClickHouse/pull/27830) ([zhanglistar](https://github.com/zhanglistar)).
+* Add `log_queries_probability` setting that allows user to write to query_log only a sample of queries. Closes [#16609](https://github.com/ClickHouse/ClickHouse/issues/16609). [#27527](https://github.com/ClickHouse/ClickHouse/pull/27527) ([Nikolay Degterinsky](https://github.com/evillique)).
+
+#### Experimental Feature
+
+* `web` type of disks to store readonly tables on web server in form of static files. See [#23982](https://github.com/ClickHouse/ClickHouse/issues/23982). [#25251](https://github.com/ClickHouse/ClickHouse/pull/25251) ([Kseniia Sumarokova](https://github.com/kssenii)). This is mostly needed to faciliate testing of operation on shared storage and for easy importing of datasets. Not recommended to use before release 21.11.
+* Added new commands `BACKUP` and `RESTORE`. [#21945](https://github.com/ClickHouse/ClickHouse/pull/21945) ([Vitaly Baranov](https://github.com/vitlibar)). This is under development and not intended to be used in current version.
+
+#### Performance Improvement
+
+* Speed up `sumIf` and `countIf` aggregation functions. [#28272](https://github.com/ClickHouse/ClickHouse/pull/28272) ([Raúl Marín](https://github.com/Algunenano)).
+* Create virtual projection for `minmax` indices. Now, when `allow_experimental_projection_optimization` is enabled, queries will use minmax index instead of reading the data when possible. [#26286](https://github.com/ClickHouse/ClickHouse/pull/26286) ([Amos Bird](https://github.com/amosbird)).
+* Introducing two checks in `sequenceMatch` and `sequenceCount` that allow for early exit when some deterministic part of the sequence pattern is missing from the events list. This change unlocks many queries that would previously fail due to reaching operations cap, and generally speeds up the pipeline. [#27729](https://github.com/ClickHouse/ClickHouse/pull/27729) ([Jakub Kuklis](https://github.com/jkuklis)).
+* Enhance primary key analysis with always monotonic information of binary functions, notably non-zero constant division. [#28302](https://github.com/ClickHouse/ClickHouse/pull/28302) ([Amos Bird](https://github.com/amosbird)).
+* Make `hasAll` filter condition leverage bloom filter data-skipping indexes. [#27984](https://github.com/ClickHouse/ClickHouse/pull/27984) ([Braulio Valdivielso Martínez](https://github.com/BraulioVM)).
+* Speed up data parts loading by delaying table startup process. [#28313](https://github.com/ClickHouse/ClickHouse/pull/28313) ([Amos Bird](https://github.com/amosbird)).
+* Fixed possible excessive number of conditions moved from `WHERE` to `PREWHERE` (optimization controlled by settings `optimize_move_to_prewhere`). [#28139](https://github.com/ClickHouse/ClickHouse/pull/28139) ([lthaooo](https://github.com/lthaooo)).
+* Enable `optimize_distributed_group_by_sharding_key` by default. [#28105](https://github.com/ClickHouse/ClickHouse/pull/28105) ([Azat Khuzhin](https://github.com/azat)).
+
+#### Improvement
+
+* Check cluster name before creating `Distributed` table, do not allow to create a table with incorrect cluster name. Fixes [#27832](https://github.com/ClickHouse/ClickHouse/issues/27832). [#27927](https://github.com/ClickHouse/ClickHouse/pull/27927) ([tavplubix](https://github.com/tavplubix)).
+* Add aggregate function `quantileBFloat16Weighted` similarly to other quantile...Weighted functions. This closes [#27745](https://github.com/ClickHouse/ClickHouse/issues/27745). [#27758](https://github.com/ClickHouse/ClickHouse/pull/27758) ([Ivan Novitskiy](https://github.com/RedClusive)).
+* Allow to create dictionaries with empty attributes list. [#27905](https://github.com/ClickHouse/ClickHouse/pull/27905) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add interactive documentation in `clickhouse-client` about how to reset the password. This is useful in scenario when user has installed ClickHouse, set up the password and instantly forget it. See [#27750](https://github.com/ClickHouse/ClickHouse/issues/27750). [#27903](https://github.com/ClickHouse/ClickHouse/pull/27903) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support the case when the data is enclosed in array in `JSONAsString` input format. Closes [#25517](https://github.com/ClickHouse/ClickHouse/issues/25517). [#25633](https://github.com/ClickHouse/ClickHouse/pull/25633) ([Kruglov Pavel](https://github.com/Avogar)).
+* Add new column `last_queue_update_exception` to `system.replicas` table. [#26843](https://github.com/ClickHouse/ClickHouse/pull/26843) ([nvartolomei](https://github.com/nvartolomei)).
+* Support reconnections on failover for `MaterializedPostgreSQL` tables. Closes [#28529](https://github.com/ClickHouse/ClickHouse/issues/28529). [#28614](https://github.com/ClickHouse/ClickHouse/pull/28614) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Generate a unique server UUID on first server start. [#20089](https://github.com/ClickHouse/ClickHouse/pull/20089) ([Bharat Nallan](https://github.com/bharatnc)).
+* Introduce `connection_wait_timeout` (default to 5 seconds, 0 - do not wait) setting for `MySQL` engine. [#28474](https://github.com/ClickHouse/ClickHouse/pull/28474) ([Azat Khuzhin](https://github.com/azat)).
+* Do not allow creating `MaterializedPostgreSQL` with bad arguments. Closes [#28423](https://github.com/ClickHouse/ClickHouse/issues/28423). [#28430](https://github.com/ClickHouse/ClickHouse/pull/28430) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Use real tmp file instead of predefined "rows_sources" for vertical merges. This avoids generating garbage directories in tmp disks. [#28299](https://github.com/ClickHouse/ClickHouse/pull/28299) ([Amos Bird](https://github.com/amosbird)).
+* Added `libhdfs3_conf` in server config instead of export env `LIBHDFS3_CONF` in clickhouse-server.service. This is for configuration of interaction with HDFS. [#28268](https://github.com/ClickHouse/ClickHouse/pull/28268) ([Zhichang Yu](https://github.com/yuzhichang)).
+* Fix removing of parts in a Temporary state which can lead to an unexpected exception (`Part %name% doesn't exist`). Fixes [#23661](https://github.com/ClickHouse/ClickHouse/issues/23661). [#28221](https://github.com/ClickHouse/ClickHouse/pull/28221) [#28221](https://github.com/ClickHouse/ClickHouse/issues/28221)) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `zookeeper_log.address` (before the first patch in this PR the address was always `::`) and reduce number of calls `getpeername(2)` for this column (since each time entry for `zookeeper_log` is added `getpeername()` is called, cache this address in the zookeeper client to avoid this). [#28212](https://github.com/ClickHouse/ClickHouse/pull/28212) ([Azat Khuzhin](https://github.com/azat)).
+* Support implicit conversions between index in operator `[]` and key of type `Map` (e.g. different `Int` types, `String` and `FixedString`). [#28096](https://github.com/ClickHouse/ClickHouse/pull/28096) ([Anton Popov](https://github.com/CurtizJ)).
+* Support `ON CONFLICT` clause when inserting into PostgreSQL table engine or table function. Closes [#27727](https://github.com/ClickHouse/ClickHouse/issues/27727). [#28081](https://github.com/ClickHouse/ClickHouse/pull/28081) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Lower restrictions for `Enum` data type to allow attaching compatible data. Closes [#26672](https://github.com/ClickHouse/ClickHouse/issues/26672). [#28028](https://github.com/ClickHouse/ClickHouse/pull/28028) ([Dmitry Novik](https://github.com/novikd)).
+* Add a setting `empty_result_for_aggregation_by_constant_keys_on_empty_set` to control the behavior of grouping by constant keys on empty set. This is to bring back the old baviour of [#6842](https://github.com/ClickHouse/ClickHouse/issues/6842). [#27932](https://github.com/ClickHouse/ClickHouse/pull/27932) ([Amos Bird](https://github.com/amosbird)).
+* Added `replication_wait_for_inactive_replica_timeout` setting. It allows to specify how long to wait for inactive replicas to execute `ALTER`/`OPTIMZE`/`TRUNCATE` query (default is 120 seconds). If `replication_alter_partitions_sync` is 2 and some replicas are not active for more than `replication_wait_for_inactive_replica_timeout` seconds, then `UNFINISHED` will be thrown. [#27931](https://github.com/ClickHouse/ClickHouse/pull/27931) ([tavplubix](https://github.com/tavplubix)).
+* Support lambda argument for `APPLY` column transformer which allows applying functions with more than one argument. This is for [#27877](https://github.com/ClickHouse/ClickHouse/issues/27877). [#27901](https://github.com/ClickHouse/ClickHouse/pull/27901) ([Amos Bird](https://github.com/amosbird)).
+* Enable `tcp_keep_alive_timeout` by default. [#27882](https://github.com/ClickHouse/ClickHouse/pull/27882) ([Azat Khuzhin](https://github.com/azat)).
+* Improve remote query cancelation (in case of remote server abnormaly terminated). [#27881](https://github.com/ClickHouse/ClickHouse/pull/27881) ([Azat Khuzhin](https://github.com/azat)).
+* Use Multipart copy upload for large S3 objects. [#27858](https://github.com/ClickHouse/ClickHouse/pull/27858) ([ianton-ru](https://github.com/ianton-ru)).
+* Allow symlink traversal for library dictionaty path. [#27815](https://github.com/ClickHouse/ClickHouse/pull/27815) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Now `ALTER MODIFY COLUM` `T` to `Nullable(T)` doesn't require mutation. [#27787](https://github.com/ClickHouse/ClickHouse/pull/27787) ([victorgao](https://github.com/kafka1991)).
+* Don't silently ignore errors and don't count delays in `ReadBufferFromS3`. [#27484](https://github.com/ClickHouse/ClickHouse/pull/27484) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Improve `ALTER ... MATERIALIZE TTL` by recalculating metadata only without actual TTL action. [#27019](https://github.com/ClickHouse/ClickHouse/pull/27019) ([lthaooo](https://github.com/lthaooo)).
+* Allow reading the list of custom top level domains without a new line at EOF. [#28213](https://github.com/ClickHouse/ClickHouse/pull/28213) ([Azat Khuzhin](https://github.com/azat)).
+
+#### Bug Fix
+
+* Fix cases, when reading compressed data from `carbon-clickhouse` fails with 'attempt to read after end of file'. Closes [#26149](https://github.com/ClickHouse/ClickHouse/issues/26149). [#28150](https://github.com/ClickHouse/ClickHouse/pull/28150) ([FArthur-cmd](https://github.com/FArthur-cmd)).
+* Fix checking access grants when executing `GRANT WITH REPLACE` statement with `ON CLUSTER` clause. This PR improves fix [#27001](https://github.com/ClickHouse/ClickHouse/pull/27701). [#27983](https://github.com/ClickHouse/ClickHouse/pull/27983) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Allow selecting with `extremes = 1` from a column of the type `LowCardinality(UUID)`. [#27918](https://github.com/ClickHouse/ClickHouse/pull/27918) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix PostgreSQL-style cast (`::` operator) with negative numbers. [#27876](https://github.com/ClickHouse/ClickHouse/pull/27876) ([Anton Popov](https://github.com/CurtizJ)).
+* After [#26864](https://github.com/ClickHouse/ClickHouse/pull/26864). Fix shutdown of `NamedSessionStorage`: session contexts stored in `NamedSessionStorage` are now destroyed before destroying the global context. [#27875](https://github.com/ClickHouse/ClickHouse/pull/27875) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Bugfix for `windowFunnel` "strict" mode. This fixes [#27469](https://github.com/ClickHouse/ClickHouse/issues/27469). [#27563](https://github.com/ClickHouse/ClickHouse/pull/27563) ([achimbab](https://github.com/achimbab)).
+* Fix infinite loop while reading truncated `bzip2` archive. [#28543](https://github.com/ClickHouse/ClickHouse/pull/28543) ([Azat Khuzhin](https://github.com/azat)).
+* Fix UUID overlap in `DROP TABLE` for internal DDL from `MaterializedMySQL`. MaterializedMySQL is an experimental feature. [#28533](https://github.com/ClickHouse/ClickHouse/pull/28533) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `There is no subcolumn` error, while select from tables, which have `Nested` columns and scalar columns with dot in name and the same prefix as `Nested` (e.g. `n.id UInt32, n.arr1 Array(UInt64), n.arr2 Array(UInt64)`). [#28531](https://github.com/ClickHouse/ClickHouse/pull/28531) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix bug which can lead to error `Existing table metadata in ZooKeeper differs in sorting key expression.` after ALTER of `ReplicatedVersionedCollapsingMergeTree`. Fixes [#28515](https://github.com/ClickHouse/ClickHouse/issues/28515). [#28528](https://github.com/ClickHouse/ClickHouse/pull/28528) ([alesapin](https://github.com/alesapin)).
+* Fixed possible ZooKeeper watches leak (minor issue) on background processing of distributed DDL queue. Closes [#26036](https://github.com/ClickHouse/ClickHouse/issues/26036). [#28446](https://github.com/ClickHouse/ClickHouse/pull/28446) ([tavplubix](https://github.com/tavplubix)).
+* Fix missing quoting of table names in `MaterializedPostgreSQL` engine. Closes [#28316](https://github.com/ClickHouse/ClickHouse/issues/28316). [#28433](https://github.com/ClickHouse/ClickHouse/pull/28433) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix the wrong behaviour of non joined rows from nullable column. Close [#27691](https://github.com/ClickHouse/ClickHouse/issues/27691). [#28349](https://github.com/ClickHouse/ClickHouse/pull/28349) ([vdimir](https://github.com/vdimir)).
+* Fix NOT-IN index optimization when not all key columns are used. This fixes [#28120](https://github.com/ClickHouse/ClickHouse/issues/28120). [#28315](https://github.com/ClickHouse/ClickHouse/pull/28315) ([Amos Bird](https://github.com/amosbird)).
+* Fix intersecting parts due to new part had been replaced with an empty part. [#28310](https://github.com/ClickHouse/ClickHouse/pull/28310) ([Azat Khuzhin](https://github.com/azat)).
+* Fix inconsistent result in queries with `ORDER BY` and `Merge` tables with enabled setting `optimize_read_in_order`. [#28266](https://github.com/ClickHouse/ClickHouse/pull/28266) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix possible read of uninitialized memory for queries with `Nullable(LowCardinality)` type and the setting `extremes` set to 1. Fixes [#28165](https://github.com/ClickHouse/ClickHouse/issues/28165). [#28205](https://github.com/ClickHouse/ClickHouse/pull/28205) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Multiple small fixes for projections. See detailed description in the PR. [#28178](https://github.com/ClickHouse/ClickHouse/pull/28178) ([Amos Bird](https://github.com/amosbird)).
+* Fix extremely rare segfaults on shutdown due to incorrect order of context/config reloader shutdown. [#28088](https://github.com/ClickHouse/ClickHouse/pull/28088) ([nvartolomei](https://github.com/nvartolomei)).
+* Fix handling null value with type of `Nullable(String)` in function `JSONExtract`. This fixes [#27929](https://github.com/ClickHouse/ClickHouse/issues/27929) and [#27930](https://github.com/ClickHouse/ClickHouse/issues/27930). This was introduced in https://github.com/ClickHouse/ClickHouse/pull/25452 . [#27939](https://github.com/ClickHouse/ClickHouse/pull/27939) ([Amos Bird](https://github.com/amosbird)).
+* Multiple fixes for the new `clickhouse-keeper` tool. Fix a rare bug in `clickhouse-keeper` when the client can receive a watch response before request-response. [#28197](https://github.com/ClickHouse/ClickHouse/pull/28197) ([alesapin](https://github.com/alesapin)). Fix incorrect behavior in `clickhouse-keeper` when list watches (`getChildren`) triggered with `set` requests for children. [#28190](https://github.com/ClickHouse/ClickHouse/pull/28190) ([alesapin](https://github.com/alesapin)). Fix rare case when changes of `clickhouse-keeper` settings may lead to lost logs and server hung. [#28360](https://github.com/ClickHouse/ClickHouse/pull/28360) ([alesapin](https://github.com/alesapin)). Fix bug in `clickhouse-keeper` which can lead to endless logs when `rotate_logs_interval` decreased. [#28152](https://github.com/ClickHouse/ClickHouse/pull/28152) ([alesapin](https://github.com/alesapin)).
+
+#### Build/Testing/Packaging Improvement
+
+* Enable Thread Fuzzer in Stress Test. Thread Fuzzer is ClickHouse feature that allows to test more permutations of thread scheduling and discover more potential issues. This closes [#9813](https://github.com/ClickHouse/ClickHouse/issues/9813). This closes [#9814](https://github.com/ClickHouse/ClickHouse/issues/9814). This closes [#9515](https://github.com/ClickHouse/ClickHouse/issues/9515). This closes [#9516](https://github.com/ClickHouse/ClickHouse/issues/9516). [#27538](https://github.com/ClickHouse/ClickHouse/pull/27538) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add new log level `test` for testing environments. It is even more verbose than the default `trace`. [#28559](https://github.com/ClickHouse/ClickHouse/pull/28559) ([alesapin](https://github.com/alesapin)).
+* Print out git status information at CMake configure stage. [#28047](https://github.com/ClickHouse/ClickHouse/pull/28047) ([Braulio Valdivielso Martínez](https://github.com/BraulioVM)).
+* Temporarily switched ubuntu apt repository to mirror ru.archive.ubuntu.com as the default one (archive.ubuntu.com) is not responding from our CI. [#28016](https://github.com/ClickHouse/ClickHouse/pull/28016) ([Ilya Yatsishin](https://github.com/qoega)).
+
+
+
+### ClickHouse release v21.9, 2021-09-09
+
+#### Backward Incompatible Change
+
+* Do not output trailing zeros in text representation of `Decimal` types. Example: `1.23` will be printed instead of `1.230000` for decimal with scale 6. This closes [#15794](https://github.com/ClickHouse/ClickHouse/issues/15794). It may introduce slight incompatibility if your applications somehow relied on the trailing zeros. Serialization in output formats can be controlled with the setting `output_format_decimal_trailing_zeros`. Implementation of `toString` and casting to String is changed unconditionally. [#27680](https://github.com/ClickHouse/ClickHouse/pull/27680) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Do not allow to apply parametric aggregate function with `-Merge` combinator to aggregate function state if state was produced by aggregate function with different parameters. For example, state of `fooState(42)(x)` cannot be finalized with `fooMerge(s)` or `fooMerge(123)(s)`, parameters must be specified explicitly like `fooMerge(42)(s)` and must be equal. It does not affect some special aggregate functions like `quantile` and `sequence*` that use parameters for finalization only. [#26847](https://github.com/ClickHouse/ClickHouse/pull/26847) ([tavplubix](https://github.com/tavplubix)).
+* Under clickhouse-local, always treat local addresses with a port as remote. [#26736](https://github.com/ClickHouse/ClickHouse/pull/26736) ([Raúl Marín](https://github.com/Algunenano)).
+* Fix the issue that in case of some sophisticated query with column aliases identical to the names of expressions, bad cast may happen. This fixes [#25447](https://github.com/ClickHouse/ClickHouse/issues/25447). This fixes [#26914](https://github.com/ClickHouse/ClickHouse/issues/26914). This fix may introduce backward incompatibility: if there are different expressions with identical names, exception will be thrown. It may break some rare cases when `enable_optimize_predicate_expression` is set. [#26639](https://github.com/ClickHouse/ClickHouse/pull/26639) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now, scalar subquery always returns `Nullable` result if it's type can be `Nullable`. It is needed because in case of empty subquery it's result should be `Null`. Previously, it was possible to get error about incompatible types (type deduction does not execute scalar subquery, and it could use not-nullable type). Scalar subquery with empty result which can't be converted to `Nullable` (like `Array` or `Tuple`) now throws error. Fixes [#25411](https://github.com/ClickHouse/ClickHouse/issues/25411). [#26423](https://github.com/ClickHouse/ClickHouse/pull/26423) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Introduce syntax for here documents. Example `SELECT $doc$ VALUE $doc$`. [#26671](https://github.com/ClickHouse/ClickHouse/pull/26671) ([Maksim Kita](https://github.com/kitaisreal)). This change is backward incompatible if in query there are identifiers that contain `$` [#28768](https://github.com/ClickHouse/ClickHouse/issues/28768).
+* Now indices can handle Nullable types, including `isNull` and `isNotNull`. [#12433](https://github.com/ClickHouse/ClickHouse/pull/12433) and [#12455](https://github.com/ClickHouse/ClickHouse/pull/12455) ([Amos Bird](https://github.com/amosbird)) and [#27250](https://github.com/ClickHouse/ClickHouse/pull/27250) ([Azat Khuzhin](https://github.com/azat)). But this was done with on-disk format changes, and even though new server can read old data, old server cannot. Also, in case you have `MINMAX` data skipping indices, you may get `Data after mutation/merge is not byte-identical` error, since new index will have `.idx2` extension while before it was `.idx`. That said, that you should not delay updating all existing replicas, in this case, otherwise, if old replica (<21.9) will download data from new replica with 21.9+ it will not be able to apply index for downloaded part.
+
+#### New Feature
+
+* Implementation of short circuit function evaluation, closes [#12587](https://github.com/ClickHouse/ClickHouse/issues/12587). Add settings `short_circuit_function_evaluation` to configure short circuit function evaluation. [#23367](https://github.com/ClickHouse/ClickHouse/pull/23367) ([Kruglov Pavel](https://github.com/Avogar)).
+* Add support for INTERSECT, EXCEPT, ANY, ALL operators. [#24757](https://github.com/ClickHouse/ClickHouse/pull/24757) ([Kirill Ershov](https://github.com/zdikov)). ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add support for encryption at the virtual file system level (data encryption at rest) using AES-CTR algorithm. [#24206](https://github.com/ClickHouse/ClickHouse/pull/24206) ([Latysheva Alexandra](https://github.com/alexelex)). ([Vitaly Baranov](https://github.com/vitlibar)) [#26733](https://github.com/ClickHouse/ClickHouse/pull/26733) [#26377](https://github.com/ClickHouse/ClickHouse/pull/26377) [#26465](https://github.com/ClickHouse/ClickHouse/pull/26465).
+* Added natural language processing (NLP) functions for tokenization, stemming, lemmatizing and search in synonyms extensions. [#24997](https://github.com/ClickHouse/ClickHouse/pull/24997) ([Nikolay Degterinsky](https://github.com/evillique)).
+* Added integration with S2 geometry library. [#24980](https://github.com/ClickHouse/ClickHouse/pull/24980) ([Andr0901](https://github.com/Andr0901)). ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Add SQLite table engine, table function, database engine. [#24194](https://github.com/ClickHouse/ClickHouse/pull/24194) ([Arslan Gumerov](https://github.com/g-arslan)). ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Added support for custom query for `MySQL`, `PostgreSQL`, `ClickHouse`, `JDBC`, `Cassandra` dictionary source. Closes [#1270](https://github.com/ClickHouse/ClickHouse/issues/1270). [#26995](https://github.com/ClickHouse/ClickHouse/pull/26995) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add shared (replicated) storage of user, roles, row policies, quotas and settings profiles through ZooKeeper. [#27426](https://github.com/ClickHouse/ClickHouse/pull/27426) ([Kevin Michel](https://github.com/kmichel-aiven)).
+* Add compression for `INTO OUTFILE` that automatically choose compression algorithm. Closes [#3473](https://github.com/ClickHouse/ClickHouse/issues/3473). [#27134](https://github.com/ClickHouse/ClickHouse/pull/27134) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
+* Add `INSERT ... FROM INFILE` similarly to `SELECT ... INTO OUTFILE`. [#27655](https://github.com/ClickHouse/ClickHouse/pull/27655) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
+* Added `complex_key_range_hashed` dictionary. Closes [#22029](https://github.com/ClickHouse/ClickHouse/issues/22029). [#27629](https://github.com/ClickHouse/ClickHouse/pull/27629) ([Maksim Kita](https://github.com/kitaisreal)).
+* Support expressions in JOIN ON section. Close [#21868](https://github.com/ClickHouse/ClickHouse/issues/21868). [#24420](https://github.com/ClickHouse/ClickHouse/pull/24420) ([Vladimir C](https://github.com/vdimir)).
+* When client connects to server, it receives information about all warnings that are already were collected by server. (It can be disabled by using option `--no-warnings`). Add `system.warnings` table to collect warnings about server configuration. [#26246](https://github.com/ClickHouse/ClickHouse/pull/26246) ([Filatenkov Artur](https://github.com/FArthur-cmd)). [#26282](https://github.com/ClickHouse/ClickHouse/pull/26282) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
+* Allow using constant expressions from with and select in aggregate function parameters. Close [#10945](https://github.com/ClickHouse/ClickHouse/issues/10945). [#27531](https://github.com/ClickHouse/ClickHouse/pull/27531) ([abel-cheng](https://github.com/abel-cheng)).
+* Add `tupleToNameValuePairs`, a function that turns a named tuple into an array of pairs. [#27505](https://github.com/ClickHouse/ClickHouse/pull/27505) ([Braulio Valdivielso Martínez](https://github.com/BraulioVM)).
+* Add support for `bzip2` compression method for import/export. Closes [#22428](https://github.com/ClickHouse/ClickHouse/issues/22428). [#27377](https://github.com/ClickHouse/ClickHouse/pull/27377) ([Nikolay Degterinsky](https://github.com/evillique)).
+* Added `bitmapSubsetOffsetLimit(bitmap, offset, cardinality_limit)` function. It creates a subset of bitmap limit the results to `cardinality_limit` with offset of `offset`. [#27234](https://github.com/ClickHouse/ClickHouse/pull/27234) ([DHBin](https://github.com/DHBin)).
+* Add column `default_database` to `system.users`. [#27054](https://github.com/ClickHouse/ClickHouse/pull/27054) ([kevin wan](https://github.com/MaxWk)).
+* Supported `cluster` macros inside table functions 'cluster' and 'clusterAllReplicas'. [#26913](https://github.com/ClickHouse/ClickHouse/pull/26913) ([polyprogrammist](https://github.com/PolyProgrammist)).
+* Add new functions `currentRoles()`, `enabledRoles()`, `defaultRoles()`. [#26780](https://github.com/ClickHouse/ClickHouse/pull/26780) ([Vitaly Baranov](https://github.com/vitlibar)).
+* New functions `currentProfiles()`, `enabledProfiles()`, `defaultProfiles()`. [#26714](https://github.com/ClickHouse/ClickHouse/pull/26714) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Add functions that return (initial_)query_id of the current query. This closes [#23682](https://github.com/ClickHouse/ClickHouse/issues/23682). [#26410](https://github.com/ClickHouse/ClickHouse/pull/26410) ([Alexey Boykov](https://github.com/mathalex)).
+* Add `REPLACE GRANT` feature. [#26384](https://github.com/ClickHouse/ClickHouse/pull/26384) ([Caspian](https://github.com/Cas-pian)).
+* `EXPLAIN` query now has `EXPLAIN ESTIMATE ...` mode that will show information about read rows, marks and parts from MergeTree tables. Closes [#23941](https://github.com/ClickHouse/ClickHouse/issues/23941). [#26131](https://github.com/ClickHouse/ClickHouse/pull/26131) ([fastio](https://github.com/fastio)).
+* Added `system.zookeeper_log` table. All actions of ZooKeeper client are logged into this table. Implements [#25449](https://github.com/ClickHouse/ClickHouse/issues/25449). [#26129](https://github.com/ClickHouse/ClickHouse/pull/26129) ([tavplubix](https://github.com/tavplubix)).
+* Zero-copy replication for `ReplicatedMergeTree` over `HDFS` storage. [#25918](https://github.com/ClickHouse/ClickHouse/pull/25918) ([Zhichang Yu](https://github.com/yuzhichang)).
+* Allow to insert Nested type as array of structs in `Arrow`, `ORC` and `Parquet` input format. [#25902](https://github.com/ClickHouse/ClickHouse/pull/25902) ([Kruglov Pavel](https://github.com/Avogar)).
+* Add a new datatype `Date32` (store data as Int32), support date range same with `DateTime64` support load parquet date32 to ClickHouse `Date32` Add new function `toDate32` like `toDate`. [#25774](https://github.com/ClickHouse/ClickHouse/pull/25774) ([LiuNeng](https://github.com/liuneng1994)).
+* Allow setting default database for users. [#25268](https://github.com/ClickHouse/ClickHouse/issues/25268). [#25687](https://github.com/ClickHouse/ClickHouse/pull/25687) ([kevin wan](https://github.com/MaxWk)).
+* Add an optional parameter to `MongoDB` engine to accept connection string options and support SSL connection. Closes [#21189](https://github.com/ClickHouse/ClickHouse/issues/21189). Closes [#21041](https://github.com/ClickHouse/ClickHouse/issues/21041). [#22045](https://github.com/ClickHouse/ClickHouse/pull/22045) ([Omar Bazaraa](https://github.com/OmarBazaraa)).
+
+#### Experimental Feature
+
+* Added a compression codec `AES_128_GCM_SIV` which encrypts columns instead of compressing them. [#19896](https://github.com/ClickHouse/ClickHouse/pull/19896) ([PHO](https://github.com/depressed-pho)). Will be rewritten, do not use.
+* Rename `MaterializeMySQL` to `MaterializedMySQL`. [#26822](https://github.com/ClickHouse/ClickHouse/pull/26822) ([tavplubix](https://github.com/tavplubix)).
+
+#### Performance Improvement
+
+* Improve the performance of fast queries when `max_execution_time = 0` by reducing the number of `clock_gettime` system calls. [#27325](https://github.com/ClickHouse/ClickHouse/pull/27325) ([filimonov](https://github.com/filimonov)).
+* Specialize date time related comparison to achieve better performance. This fixes [#27083](https://github.com/ClickHouse/ClickHouse/issues/27083) . [#27122](https://github.com/ClickHouse/ClickHouse/pull/27122) ([Amos Bird](https://github.com/amosbird)).
+* Share file descriptors in concurrent reads of the same files. There is no noticeable performance difference on Linux. But the number of opened files will be significantly (10..100 times) lower on typical servers and it makes operations easier. See [#26214](https://github.com/ClickHouse/ClickHouse/issues/26214). [#26768](https://github.com/ClickHouse/ClickHouse/pull/26768) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve latency of short queries, that require reading from tables with large number of columns. [#26371](https://github.com/ClickHouse/ClickHouse/pull/26371) ([Anton Popov](https://github.com/CurtizJ)).
+* Don't build sets for indices when analyzing a query. [#26365](https://github.com/ClickHouse/ClickHouse/pull/26365) ([Raúl Marín](https://github.com/Algunenano)).
+* Vectorize the SUM of Nullable integer types with native representation ([David Manzanares](https://github.com/davidmanzanares), [Raúl Marín](https://github.com/Algunenano)). [#26248](https://github.com/ClickHouse/ClickHouse/pull/26248) ([Raúl Marín](https://github.com/Algunenano)).
+* Compile expressions involving columns with `Enum` types. [#26237](https://github.com/ClickHouse/ClickHouse/pull/26237) ([Maksim Kita](https://github.com/kitaisreal)).
+* Compile aggregate functions `groupBitOr`, `groupBitAnd`, `groupBitXor`. [#26161](https://github.com/ClickHouse/ClickHouse/pull/26161) ([Maksim Kita](https://github.com/kitaisreal)).
+* Improved memory usage with better block size prediction when reading empty DEFAULT columns. Closes [#17317](https://github.com/ClickHouse/ClickHouse/issues/17317). [#25917](https://github.com/ClickHouse/ClickHouse/pull/25917) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Reduce memory usage and number of read rows in queries with `ORDER BY primary_key`. [#25721](https://github.com/ClickHouse/ClickHouse/pull/25721) ([Anton Popov](https://github.com/CurtizJ)).
+* Enable `distributed_push_down_limit` by default. [#27104](https://github.com/ClickHouse/ClickHouse/pull/27104) ([Azat Khuzhin](https://github.com/azat)).
+* Make `toTimeZone` monotonicity when timeZone is a constant value to support partition puring when use sql like:. [#26261](https://github.com/ClickHouse/ClickHouse/pull/26261) ([huangzhaowei](https://github.com/SaintBacchus)).
+
+#### Improvement
+
+* Mark window functions as ready for general use. Remove the `allow_experimental_window_functions` setting. [#27184](https://github.com/ClickHouse/ClickHouse/pull/27184) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Improve compatibility with non-whole-minute timezone offsets. [#27080](https://github.com/ClickHouse/ClickHouse/pull/27080) ([Raúl Marín](https://github.com/Algunenano)).
+* If file descriptor in `File` table is regular file - allow to read multiple times from it. It allows `clickhouse-local` to read multiple times from stdin (with multiple SELECT queries or subqueries) if stdin is a regular file like `clickhouse-local --query "SELECT * FROM table UNION ALL SELECT * FROM table" ... < file`. This closes [#11124](https://github.com/ClickHouse/ClickHouse/issues/11124). Co-authored with ([alexey-milovidov](https://github.com/alexey-milovidov)). [#25960](https://github.com/ClickHouse/ClickHouse/pull/25960) ([BoloniniD](https://github.com/BoloniniD)).
+* Remove duplicate index analysis and avoid possible invalid limit checks during projection analysis. [#27742](https://github.com/ClickHouse/ClickHouse/pull/27742) ([Amos Bird](https://github.com/amosbird)).
+* Enable query parameters to be passed in the body of HTTP requests. [#27706](https://github.com/ClickHouse/ClickHouse/pull/27706) ([Hermano Lustosa](https://github.com/hllustosa)).
+* Disallow `arrayJoin` on partition expressions. [#27648](https://github.com/ClickHouse/ClickHouse/pull/27648) ([Raúl Marín](https://github.com/Algunenano)).
+* Log client IP address if authentication fails. [#27514](https://github.com/ClickHouse/ClickHouse/pull/27514) ([Misko Lee](https://github.com/imiskolee)).
+* Use bytes instead of strings for binary data in the GRPC protocol. [#27431](https://github.com/ClickHouse/ClickHouse/pull/27431) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Send response with error message if HTTP port is not set and user tries to send HTTP request to TCP port. [#27385](https://github.com/ClickHouse/ClickHouse/pull/27385) ([Braulio Valdivielso Martínez](https://github.com/BraulioVM)).
+* Add `_CAST` function for internal usage, which will not preserve type nullability, but non-internal cast will preserve according to setting `cast_keep_nullable`. Closes [#12636](https://github.com/ClickHouse/ClickHouse/issues/12636). [#27382](https://github.com/ClickHouse/ClickHouse/pull/27382) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add setting `log_formatted_queries` to log additional formatted query into `system.query_log`. It's useful for normalized query analysis because functions like `normalizeQuery` and `normalizeQueryKeepNames` don't parse/format queries in order to achieve better performance. [#27380](https://github.com/ClickHouse/ClickHouse/pull/27380) ([Amos Bird](https://github.com/amosbird)).
+* Add two settings `max_hyperscan_regexp_length` and `max_hyperscan_regexp_total_length` to prevent huge regexp being used in hyperscan related functions, such as `multiMatchAny`. [#27378](https://github.com/ClickHouse/ClickHouse/pull/27378) ([Amos Bird](https://github.com/amosbird)).
+* Memory consumed by bitmap aggregate functions now is taken into account for memory limits. This closes [#26555](https://github.com/ClickHouse/ClickHouse/issues/26555). [#27252](https://github.com/ClickHouse/ClickHouse/pull/27252) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add 10 seconds cache for S3 proxy resolver. [#27216](https://github.com/ClickHouse/ClickHouse/pull/27216) ([ianton-ru](https://github.com/ianton-ru)).
+* Split global mutex into individual regexp construction. This helps avoid huge regexp construction blocking other related threads. [#27211](https://github.com/ClickHouse/ClickHouse/pull/27211) ([Amos Bird](https://github.com/amosbird)).
+* Support schema for PostgreSQL database engine. Closes [#27166](https://github.com/ClickHouse/ClickHouse/issues/27166). [#27198](https://github.com/ClickHouse/ClickHouse/pull/27198) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Track memory usage in clickhouse-client. [#27191](https://github.com/ClickHouse/ClickHouse/pull/27191) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
+* Try recording `query_kind` in `system.query_log` even when query fails to start. [#27182](https://github.com/ClickHouse/ClickHouse/pull/27182) ([Amos Bird](https://github.com/amosbird)).
+* Added columns `replica_is_active` that maps replica name to is replica active status to table `system.replicas`. Closes [#27138](https://github.com/ClickHouse/ClickHouse/issues/27138). [#27180](https://github.com/ClickHouse/ClickHouse/pull/27180) ([Maksim Kita](https://github.com/kitaisreal)).
+* Allow to pass query settings via server URI in Web UI. [#27177](https://github.com/ClickHouse/ClickHouse/pull/27177) ([kolsys](https://github.com/kolsys)).
+* Add a new metric called `MaxPushedDDLEntryID` which is the maximum ddl entry id that current node push to zookeeper. [#27174](https://github.com/ClickHouse/ClickHouse/pull/27174) ([Fuwang Hu](https://github.com/fuwhu)).
+* Improved the existence condition judgment and empty string node judgment when `clickhouse-keeper` creates znode. [#27125](https://github.com/ClickHouse/ClickHouse/pull/27125) ([小路](https://github.com/nicelulu)).
+* Merge JOIN correctly handles empty set in the right. [#27078](https://github.com/ClickHouse/ClickHouse/pull/27078) ([Vladimir C](https://github.com/vdimir)).
+* Now functions can be shard-level constants, which means if it's executed in the context of some distributed table, it generates a normal column, otherwise it produces a constant value. Notable functions are: `hostName()`, `tcpPort()`, `version()`, `buildId()`, `uptime()`, etc. [#27020](https://github.com/ClickHouse/ClickHouse/pull/27020) ([Amos Bird](https://github.com/amosbird)).
+* Updated `extractAllGroupsHorizontal` - upper limit on the number of matches per row can be set via optional third argument. [#26961](https://github.com/ClickHouse/ClickHouse/pull/26961) ([Vasily Nemkov](https://github.com/Enmk)).
+* Expose `RocksDB` statistics via system.rocksdb table. Read rocksdb options from ClickHouse config (`rocksdb...` keys). NOTE: ClickHouse does not rely on RocksDB, it is just one of the additional integration storage engines. [#26821](https://github.com/ClickHouse/ClickHouse/pull/26821) ([Azat Khuzhin](https://github.com/azat)).
+* Less verbose internal RocksDB logs. NOTE: ClickHouse does not rely on RocksDB, it is just one of the additional integration storage engines. This closes [#26252](https://github.com/ClickHouse/ClickHouse/issues/26252). [#26789](https://github.com/ClickHouse/ClickHouse/pull/26789) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Changing default roles affects new sessions only. [#26759](https://github.com/ClickHouse/ClickHouse/pull/26759) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Watchdog is disabled in docker by default. Fix for not handling ctrl+c. [#26757](https://github.com/ClickHouse/ClickHouse/pull/26757) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
+* `SET PROFILE` now applies constraints too if they're set for a passed profile. [#26730](https://github.com/ClickHouse/ClickHouse/pull/26730) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Improve handling of `KILL QUERY` requests. [#26675](https://github.com/ClickHouse/ClickHouse/pull/26675) ([Raúl Marín](https://github.com/Algunenano)).
+* `mapPopulatesSeries` function supports `Map` type. [#26663](https://github.com/ClickHouse/ClickHouse/pull/26663) ([Ildus Kurbangaliev](https://github.com/ildus)).
+* Fix excessive (x2) connect attempts with `skip_unavailable_shards`. [#26658](https://github.com/ClickHouse/ClickHouse/pull/26658) ([Azat Khuzhin](https://github.com/azat)).
+* Avoid hanging `clickhouse-benchmark` if connection fails (i.e. on EMFILE). [#26656](https://github.com/ClickHouse/ClickHouse/pull/26656) ([Azat Khuzhin](https://github.com/azat)).
+* Allow more threads to be used by the Kafka engine. [#26642](https://github.com/ClickHouse/ClickHouse/pull/26642) ([feihengye](https://github.com/feihengye)).
+* Add round-robin support for `clickhouse-benchmark` (it does not differ from the regular multi host/port run except for statistics report). [#26607](https://github.com/ClickHouse/ClickHouse/pull/26607) ([Azat Khuzhin](https://github.com/azat)).
+* Executable dictionaries (`executable`, `executable_pool`) enable creation with DDL query using `clickhouse-local`. Closes [#22355](https://github.com/ClickHouse/ClickHouse/issues/22355). [#26510](https://github.com/ClickHouse/ClickHouse/pull/26510) ([Maksim Kita](https://github.com/kitaisreal)).
+* Set client query kind for `mysql` and `postgresql` compatibility protocol handlers. [#26498](https://github.com/ClickHouse/ClickHouse/pull/26498) ([anneji-dev](https://github.com/anneji-dev)).
+* Apply `LIMIT` on the shards for queries like `SELECT * FROM dist ORDER BY key LIMIT 10` w/ `distributed_push_down_limit=1`. Avoid running `Distinct`/`LIMIT BY` steps for queries like `SELECT DISTINCT shading_key FROM dist ORDER BY key`. Now `distributed_push_down_limit` is respected by `optimize_distributed_group_by_sharding_key` optimization. [#26466](https://github.com/ClickHouse/ClickHouse/pull/26466) ([Azat Khuzhin](https://github.com/azat)).
+* Updated protobuf to 3.17.3. Changelogs are available on https://github.com/protocolbuffers/protobuf/releases. [#26424](https://github.com/ClickHouse/ClickHouse/pull/26424) ([Ilya Yatsishin](https://github.com/qoega)).
+* Enable `use_hedged_requests` setting that allows to mitigate tail latencies on large clusters. [#26380](https://github.com/ClickHouse/ClickHouse/pull/26380) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve behaviour with non-existing host in user allowed host list. [#26368](https://github.com/ClickHouse/ClickHouse/pull/26368) ([ianton-ru](https://github.com/ianton-ru)).
+* Add ability to set `Distributed` directory monitor settings via CREATE TABLE (i.e. `CREATE TABLE dist (key Int) Engine=Distributed(cluster, db, table) SETTINGS monitor_batch_inserts=1` and similar). [#26336](https://github.com/ClickHouse/ClickHouse/pull/26336) ([Azat Khuzhin](https://github.com/azat)).
+* Save server address in history URLs in web UI if it differs from the origin of web UI. This closes [#26044](https://github.com/ClickHouse/ClickHouse/issues/26044). [#26322](https://github.com/ClickHouse/ClickHouse/pull/26322) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add events to profile calls to `sleep` / `sleepEachRow`. [#26320](https://github.com/ClickHouse/ClickHouse/pull/26320) ([Raúl Marín](https://github.com/Algunenano)).
+* Allow to reuse connections of shards among different clusters. It also avoids creating new connections when using `cluster` table function. [#26318](https://github.com/ClickHouse/ClickHouse/pull/26318) ([Amos Bird](https://github.com/amosbird)).
+* Control the execution period of clear old temporary directories by parameter with default value. [#26212](https://github.com/ClickHouse/ClickHouse/issues/26212). [#26313](https://github.com/ClickHouse/ClickHouse/pull/26313) ([fastio](https://github.com/fastio)).
+* Add a setting `function_range_max_elements_in_block` to tune the safety threshold for data volume generated by function `range`. This closes [#26303](https://github.com/ClickHouse/ClickHouse/issues/26303). [#26305](https://github.com/ClickHouse/ClickHouse/pull/26305) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Check hash function at table creation, not at sampling. Add settings for MergeTree, if someone create a table with incorrect sampling column but sampling never be used, disable this settings for starting the server without exception. [#26256](https://github.com/ClickHouse/ClickHouse/pull/26256) ([zhaoyu](https://github.com/zxc111)).
+* Added `output_format_avro_string_column_pattern` setting to put specified String columns to Avro as string instead of default bytes. Implements [#22414](https://github.com/ClickHouse/ClickHouse/issues/22414). [#26245](https://github.com/ClickHouse/ClickHouse/pull/26245) ([Ilya Golshtein](https://github.com/ilejn)).
+* Add information about column sizes in `system.columns` table for `Log` and `TinyLog` tables. This closes [#9001](https://github.com/ClickHouse/ClickHouse/issues/9001). [#26241](https://github.com/ClickHouse/ClickHouse/pull/26241) ([Nikolay Degterinsky](https://github.com/evillique)).
+* Don't throw exception when querying `system.detached_parts` table if there is custom disk configuration and `detached` directory does not exist on some disks. This closes [#26078](https://github.com/ClickHouse/ClickHouse/issues/26078). [#26236](https://github.com/ClickHouse/ClickHouse/pull/26236) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Check for non-deterministic functions in keys, including constant expressions like `now()`, `today()`. This closes [#25875](https://github.com/ClickHouse/ClickHouse/issues/25875). This closes [#11333](https://github.com/ClickHouse/ClickHouse/issues/11333). [#26235](https://github.com/ClickHouse/ClickHouse/pull/26235) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* convert timestamp and timestamptz data types to `DateTime64` in PostgreSQL table engine. [#26234](https://github.com/ClickHouse/ClickHouse/pull/26234) ([jasine](https://github.com/jasine)).
+* Apply aggressive IN index analysis for projections so that better projection candidate can be selected. [#26218](https://github.com/ClickHouse/ClickHouse/pull/26218) ([Amos Bird](https://github.com/amosbird)).
+* Remove GLOBAL keyword for IN when scalar function is passed. In previous versions, if user specified `GLOBAL IN f(x)` exception was thrown. [#26217](https://github.com/ClickHouse/ClickHouse/pull/26217) ([Amos Bird](https://github.com/amosbird)).
+* Add error id (like `BAD_ARGUMENTS`) to exception messages. This closes [#25862](https://github.com/ClickHouse/ClickHouse/issues/25862). [#26172](https://github.com/ClickHouse/ClickHouse/pull/26172) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix incorrect output with --progress option for clickhouse-local. Progress bar will be cleared once it gets to 100% - same as it is done for clickhouse-client. Closes [#17484](https://github.com/ClickHouse/ClickHouse/issues/17484). [#26128](https://github.com/ClickHouse/ClickHouse/pull/26128) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add `merge_selecting_sleep_ms` setting. [#26120](https://github.com/ClickHouse/ClickHouse/pull/26120) ([lthaooo](https://github.com/lthaooo)).
+* Remove complicated usage of Linux AIO with one block readahead and replace it with plain simple synchronous IO with O_DIRECT. In previous versions, the setting `min_bytes_to_use_direct_io` may not work correctly if `max_threads` is greater than one. Reading with direct IO (that is disabled by default for queries and enabled by default for large merges) will work in less efficient way. This closes [#25997](https://github.com/ClickHouse/ClickHouse/issues/25997). [#26003](https://github.com/ClickHouse/ClickHouse/pull/26003) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Flush `Distributed` table on `REPLACE TABLE` query. Resolves [#24566](https://github.com/ClickHouse/ClickHouse/issues/24566) - Do not replace (or create) table on `[CREATE OR] REPLACE TABLE ... AS SELECT` query if insertion into new table fails. Resolves [#23175](https://github.com/ClickHouse/ClickHouse/issues/23175). [#25895](https://github.com/ClickHouse/ClickHouse/pull/25895) ([tavplubix](https://github.com/tavplubix)).
+* Add `views` column to system.query_log containing the names of the (materialized or live) views executed by the query. Adds a new log table (`system.query_views_log`) that contains information about each view executed during a query. Modifies view execution: When an exception is thrown while executing a view, any view that has already startedwill continue running until it finishes. This used to be the behaviour under parallel_view_processing=true and now it's always the same behaviour. - Dependent views now report reading progress to the context. [#25714](https://github.com/ClickHouse/ClickHouse/pull/25714) ([Raúl Marín](https://github.com/Algunenano)).
+* Do connection draining asynchonously upon finishing executing distributed queries. A new server setting is added `max_threads_for_connection_collector` which specifies the number of workers to recycle connections in background. If the pool is full, connection will be drained synchronously but a bit different than before: It's drained after we send EOS to client, query will succeed immediately after receiving enough data, and any exception will be logged instead of throwing to the client. Added setting `drain_timeout` (3 seconds by default). Connection draining will disconnect upon timeout. [#25674](https://github.com/ClickHouse/ClickHouse/pull/25674) ([Amos Bird](https://github.com/amosbird)).
+* Support for multiple includes in configuration. It is possible to include users configuration, remote servers configuration from multiple sources. Simply place `<include />` element with `from_zk`, `from_env` or `incl` attribute and it will be replaced with the substitution. [#24404](https://github.com/ClickHouse/ClickHouse/pull/24404) ([nvartolomei](https://github.com/nvartolomei)).
+* Fix multiple block insertion into distributed table with `insert_distributed_one_random_shard = 1`. This is a marginal feature. Mark as improvement. [#23140](https://github.com/ClickHouse/ClickHouse/pull/23140) ([Amos Bird](https://github.com/amosbird)).
+* Support `LowCardinality` and `FixedString` keys/values for `Map` type. [#21543](https://github.com/ClickHouse/ClickHouse/pull/21543) ([hexiaoting](https://github.com/hexiaoting)).
+* Enable reloading of local disk config. [#19526](https://github.com/ClickHouse/ClickHouse/pull/19526) ([taiyang-li](https://github.com/taiyang-li)).
+
+#### Bug Fix
+
+* Fix a couple of bugs that may cause replicas to diverge. [#27808](https://github.com/ClickHouse/ClickHouse/pull/27808) ([tavplubix](https://github.com/tavplubix)).
+* Fix a rare bug in `DROP PART` which can lead to the error `Unexpected merged part intersects drop range`. [#27807](https://github.com/ClickHouse/ClickHouse/pull/27807) ([alesapin](https://github.com/alesapin)).
+* Prevent crashes for some formats when NULL (tombstone) message was coming from Kafka. Closes [#19255](https://github.com/ClickHouse/ClickHouse/issues/19255). [#27794](https://github.com/ClickHouse/ClickHouse/pull/27794) ([filimonov](https://github.com/filimonov)).
+* Fix column filtering with union distinct in subquery. Closes [#27578](https://github.com/ClickHouse/ClickHouse/issues/27578). [#27689](https://github.com/ClickHouse/ClickHouse/pull/27689) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix bad type cast when functions like `arrayHas` are applied to arrays of LowCardinality of Nullable of different non-numeric types like `DateTime` and `DateTime64`. In previous versions bad cast occurs. In new version it will lead to exception. This closes [#26330](https://github.com/ClickHouse/ClickHouse/issues/26330). [#27682](https://github.com/ClickHouse/ClickHouse/pull/27682) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix postgresql table function resulting in non-closing connections. Closes [#26088](https://github.com/ClickHouse/ClickHouse/issues/26088). [#27662](https://github.com/ClickHouse/ClickHouse/pull/27662) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fixed another case of `Unexpected merged part ... intersecting drop range ...` error. [#27656](https://github.com/ClickHouse/ClickHouse/pull/27656) ([tavplubix](https://github.com/tavplubix)).
+* Fix an error with aliased column in `Distributed` table. [#27652](https://github.com/ClickHouse/ClickHouse/pull/27652) ([Vladimir C](https://github.com/vdimir)).
+* After setting `max_memory_usage*` to non-zero value it was not possible to reset it back to 0 (unlimited). It's fixed. [#27638](https://github.com/ClickHouse/ClickHouse/pull/27638) ([tavplubix](https://github.com/tavplubix)).
+* Fixed underflow of the time value when constructing it from components. Closes [#27193](https://github.com/ClickHouse/ClickHouse/issues/27193). [#27605](https://github.com/ClickHouse/ClickHouse/pull/27605) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fix crash during projection materialization when some parts contain missing columns. This fixes [#27512](https://github.com/ClickHouse/ClickHouse/issues/27512). [#27528](https://github.com/ClickHouse/ClickHouse/pull/27528) ([Amos Bird](https://github.com/amosbird)).
+* fix metric `BackgroundMessageBrokerSchedulePoolTask`, maybe mistyped. [#27452](https://github.com/ClickHouse/ClickHouse/pull/27452) ([Ben](https://github.com/benbiti)).
+* Fix distributed queries with zero shards and aggregation. [#27427](https://github.com/ClickHouse/ClickHouse/pull/27427) ([Azat Khuzhin](https://github.com/azat)).
+* Compatibility when `/proc/meminfo` does not contain KB suffix. [#27361](https://github.com/ClickHouse/ClickHouse/pull/27361) ([Mike Kot](https://github.com/myrrc)).
+* Fix incorrect result for query with row-level security, PREWHERE and LowCardinality filter. Fixes [#27179](https://github.com/ClickHouse/ClickHouse/issues/27179). [#27329](https://github.com/ClickHouse/ClickHouse/pull/27329) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed incorrect validation of partition id for MergeTree tables that created with old syntax. [#27328](https://github.com/ClickHouse/ClickHouse/pull/27328) ([tavplubix](https://github.com/tavplubix)).
+* Fix MySQL protocol when using parallel formats (CSV / TSV). [#27326](https://github.com/ClickHouse/ClickHouse/pull/27326) ([Raúl Marín](https://github.com/Algunenano)).
+* Fix `Cannot find column` error for queries with sampling. Was introduced in [#24574](https://github.com/ClickHouse/ClickHouse/issues/24574). Fixes [#26522](https://github.com/ClickHouse/ClickHouse/issues/26522). [#27301](https://github.com/ClickHouse/ClickHouse/pull/27301) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix errors like `Expected ColumnLowCardinality, gotUInt8` or `Bad cast from type DB::ColumnVector<char8_t> to DB::ColumnLowCardinality` for some queries with `LowCardinality` in `PREWHERE`. And more importantly, fix the lack of whitespace in the error message. Fixes [#23515](https://github.com/ClickHouse/ClickHouse/issues/23515). [#27298](https://github.com/ClickHouse/ClickHouse/pull/27298) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix `distributed_group_by_no_merge = 2` with `distributed_push_down_limit = 1` or `optimize_distributed_group_by_sharding_key = 1` with `LIMIT BY` and `LIMIT OFFSET`. [#27249](https://github.com/ClickHouse/ClickHouse/pull/27249) ([Azat Khuzhin](https://github.com/azat)). These are obscure combination of settings that no one is using.
+* Fix mutation stuck on invalid partitions in non-replicated MergeTree. [#27248](https://github.com/ClickHouse/ClickHouse/pull/27248) ([Azat Khuzhin](https://github.com/azat)).
+* In case of ambiguity, lambda functions prefer its arguments to other aliases or identifiers. [#27235](https://github.com/ClickHouse/ClickHouse/pull/27235) ([Raúl Marín](https://github.com/Algunenano)).
+* Fix column structure in merge join, close [#27091](https://github.com/ClickHouse/ClickHouse/issues/27091). [#27217](https://github.com/ClickHouse/ClickHouse/pull/27217) ([Vladimir C](https://github.com/vdimir)).
+* In rare cases `system.detached_parts` table might contain incorrect information for some parts, it's fixed. Fixes [#27114](https://github.com/ClickHouse/ClickHouse/issues/27114). [#27183](https://github.com/ClickHouse/ClickHouse/pull/27183) ([tavplubix](https://github.com/tavplubix)).
+* Fix uninitialized memory in functions `multiSearch*` with empty array, close [#27169](https://github.com/ClickHouse/ClickHouse/issues/27169). [#27181](https://github.com/ClickHouse/ClickHouse/pull/27181) ([Vladimir C](https://github.com/vdimir)).
+* Fix synchronization in GRPCServer. This PR fixes [#27024](https://github.com/ClickHouse/ClickHouse/issues/27024). [#27064](https://github.com/ClickHouse/ClickHouse/pull/27064) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed `cache`, `complex_key_cache`, `ssd_cache`, `complex_key_ssd_cache` configuration parsing. Options `allow_read_expired_keys`, `max_update_queue_size`, `update_queue_push_timeout_milliseconds`, `query_wait_timeout_milliseconds` were not parsed for dictionaries with non `cache` type. [#27032](https://github.com/ClickHouse/ClickHouse/pull/27032) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix possible mutation stack due to race with DROP_RANGE. [#27002](https://github.com/ClickHouse/ClickHouse/pull/27002) ([Azat Khuzhin](https://github.com/azat)).
+* Now partition ID in queries like `ALTER TABLE ... PARTITION ID xxx` validates for correctness. Fixes [#25718](https://github.com/ClickHouse/ClickHouse/issues/25718). [#26963](https://github.com/ClickHouse/ClickHouse/pull/26963) ([alesapin](https://github.com/alesapin)).
+* Fix "Unknown column name" error with multiple JOINs in some cases, close [#26899](https://github.com/ClickHouse/ClickHouse/issues/26899). [#26957](https://github.com/ClickHouse/ClickHouse/pull/26957) ([Vladimir C](https://github.com/vdimir)).
+* Fix reading of custom TLDs (stops processing with lower buffer or bigger file). [#26948](https://github.com/ClickHouse/ClickHouse/pull/26948) ([Azat Khuzhin](https://github.com/azat)).
+* Fix error `Missing columns: 'xxx'` when `DEFAULT` column references other non materialized column without `DEFAULT` expression. Fixes [#26591](https://github.com/ClickHouse/ClickHouse/issues/26591). [#26900](https://github.com/ClickHouse/ClickHouse/pull/26900) ([alesapin](https://github.com/alesapin)).
+* Fix loading of dictionary keys in `library-bridge` for `library` dictionary source. [#26834](https://github.com/ClickHouse/ClickHouse/pull/26834) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Aggregate function parameters might be lost when applying some combinators causing exceptions like `Conversion from AggregateFunction(topKArray, Array(String)) to AggregateFunction(topKArray(10), Array(String)) is not supported`. It's fixed. Fixes [#26196](https://github.com/ClickHouse/ClickHouse/issues/26196) and [#26433](https://github.com/ClickHouse/ClickHouse/issues/26433). [#26814](https://github.com/ClickHouse/ClickHouse/pull/26814) ([tavplubix](https://github.com/tavplubix)).
+* Add `event_time_microseconds` value for `REMOVE_PART` in `system.part_log`. In previous versions is was not set. [#26720](https://github.com/ClickHouse/ClickHouse/pull/26720) ([Azat Khuzhin](https://github.com/azat)).
+* Do not remove data on ReplicatedMergeTree table shutdown to avoid creating data to metadata inconsistency. [#26716](https://github.com/ClickHouse/ClickHouse/pull/26716) ([nvartolomei](https://github.com/nvartolomei)).
+* Sometimes `SET ROLE` could work incorrectly, this PR fixes that. [#26707](https://github.com/ClickHouse/ClickHouse/pull/26707) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Some fixes for parallel formatting (https://github.com/ClickHouse/ClickHouse/issues/26694). [#26703](https://github.com/ClickHouse/ClickHouse/pull/26703) ([Raúl Marín](https://github.com/Algunenano)).
+* Fix potential nullptr dereference in window functions. This fixes [#25276](https://github.com/ClickHouse/ClickHouse/issues/25276). [#26668](https://github.com/ClickHouse/ClickHouse/pull/26668) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fix clickhouse-client history file conversion (when upgrading from the format of 3 years old version of clickhouse-client) if file is empty. [#26589](https://github.com/ClickHouse/ClickHouse/pull/26589) ([Azat Khuzhin](https://github.com/azat)).
+* Fix incorrect function names of groupBitmapAnd/Or/Xor (can be displayed in some occasions). This fixes. [#26557](https://github.com/ClickHouse/ClickHouse/pull/26557) ([Amos Bird](https://github.com/amosbird)).
+* Update `chown` cmd check in clickhouse-server docker entrypoint. It fixes the bug that cluster pod restart failed (or timeout) on kubernetes. [#26545](https://github.com/ClickHouse/ClickHouse/pull/26545) ([Ky Li](https://github.com/Kylinrix)).
+* Fix crash in `RabbitMQ` shutdown in case `RabbitMQ` setup was not started. Closes [#26504](https://github.com/ClickHouse/ClickHouse/issues/26504). [#26529](https://github.com/ClickHouse/ClickHouse/pull/26529) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix issues with `CREATE DICTIONARY` query if dictionary name or database name was quoted. Closes [#26491](https://github.com/ClickHouse/ClickHouse/issues/26491). [#26508](https://github.com/ClickHouse/ClickHouse/pull/26508) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix broken column name resolution after rewriting column aliases. This fixes [#26432](https://github.com/ClickHouse/ClickHouse/issues/26432). [#26475](https://github.com/ClickHouse/ClickHouse/pull/26475) ([Amos Bird](https://github.com/amosbird)).
+* Fix some fuzzed msan crash. Fixes [#22517](https://github.com/ClickHouse/ClickHouse/issues/22517). [#26428](https://github.com/ClickHouse/ClickHouse/pull/26428) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix infinite non joined block stream in `partial_merge_join` close [#26325](https://github.com/ClickHouse/ClickHouse/issues/26325). [#26374](https://github.com/ClickHouse/ClickHouse/pull/26374) ([Vladimir C](https://github.com/vdimir)).
+* Fix possible crash when login as dropped user. This PR fixes [#26073](https://github.com/ClickHouse/ClickHouse/issues/26073). [#26363](https://github.com/ClickHouse/ClickHouse/pull/26363) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix `optimize_distributed_group_by_sharding_key` for multiple columns (leads to incorrect result w/ `optimize_skip_unused_shards=1`/`allow_nondeterministic_optimize_skip_unused_shards=1` and multiple columns in sharding key expression). [#26353](https://github.com/ClickHouse/ClickHouse/pull/26353) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed rare bug in lost replica recovery that may cause replicas to diverge. [#26321](https://github.com/ClickHouse/ClickHouse/pull/26321) ([tavplubix](https://github.com/tavplubix)).
+* Fix zstd decompression (for import/export in zstd framing format that is unrelated to tables data) in case there are escape sequences at the end of internal buffer. Closes [#26013](https://github.com/ClickHouse/ClickHouse/issues/26013). [#26314](https://github.com/ClickHouse/ClickHouse/pull/26314) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix logical error on join with totals, close [#26017](https://github.com/ClickHouse/ClickHouse/issues/26017). [#26250](https://github.com/ClickHouse/ClickHouse/pull/26250) ([Vladimir C](https://github.com/vdimir)).
+* Remove excessive newline in `thread_name` column in `system.stack_trace` table. This fixes [#24124](https://github.com/ClickHouse/ClickHouse/issues/24124). [#26210](https://github.com/ClickHouse/ClickHouse/pull/26210) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix potential crash if more than one `untuple` expression is used. [#26179](https://github.com/ClickHouse/ClickHouse/pull/26179) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Don't throw exception in `toString` for Nullable Enum if Enum does not have a value for zero, close [#25806](https://github.com/ClickHouse/ClickHouse/issues/25806). [#26123](https://github.com/ClickHouse/ClickHouse/pull/26123) ([Vladimir C](https://github.com/vdimir)).
+* Fixed incorrect `sequence_id` in MySQL protocol packets that ClickHouse sends on exception during query execution. It might cause MySQL client to reset connection to ClickHouse server. Fixes [#21184](https://github.com/ClickHouse/ClickHouse/issues/21184). [#26051](https://github.com/ClickHouse/ClickHouse/pull/26051) ([tavplubix](https://github.com/tavplubix)).
+* Fix for the case that `cutToFirstSignificantSubdomainCustom()`/`cutToFirstSignificantSubdomainCustomWithWWW()`/`firstSignificantSubdomainCustom()` returns incorrect type for consts, and hence `optimize_skip_unused_shards` does not work:. [#26041](https://github.com/ClickHouse/ClickHouse/pull/26041) ([Azat Khuzhin](https://github.com/azat)).
+* Fix possible mismatched header when using normal projection with prewhere. This fixes [#26020](https://github.com/ClickHouse/ClickHouse/issues/26020). [#26038](https://github.com/ClickHouse/ClickHouse/pull/26038) ([Amos Bird](https://github.com/amosbird)).
+* Fix sharding_key from column w/o function for remote() (before `select * from remote('127.1', system.one, dummy)` leads to `Unknown column: dummy, there are only columns .` error). [#25824](https://github.com/ClickHouse/ClickHouse/pull/25824) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed `Not found column ...` and `Missing column ...` errors when selecting from `MaterializeMySQL`. Fixes [#23708](https://github.com/ClickHouse/ClickHouse/issues/23708), [#24830](https://github.com/ClickHouse/ClickHouse/issues/24830), [#25794](https://github.com/ClickHouse/ClickHouse/issues/25794). [#25822](https://github.com/ClickHouse/ClickHouse/pull/25822) ([tavplubix](https://github.com/tavplubix)).
+* Fix `optimize_skip_unused_shards_rewrite_in` for non-UInt64 types (may select incorrect shards eventually or throw `Cannot infer type of an empty tuple` or `Function tuple requires at least one argument`). [#25798](https://github.com/ClickHouse/ClickHouse/pull/25798) ([Azat Khuzhin](https://github.com/azat)).
+
+#### Build/Testing/Packaging Improvement
+
+* Now we ran stateful and stateless tests in random timezones. Fixes [#12439](https://github.com/ClickHouse/ClickHouse/issues/12439). Reading String as DateTime and writing DateTime as String in Protobuf format now respect timezone. Reading UInt16 as DateTime in Arrow and Parquet formats now treat it as Date and then converts to DateTime with respect to DateTime's timezone, because Date is serialized in Arrow and Parquet as UInt16. GraphiteMergeTree now respect time zone for rounding of times. Fixes [#5098](https://github.com/ClickHouse/ClickHouse/issues/5098). Author: @alexey-milovidov. [#15408](https://github.com/ClickHouse/ClickHouse/pull/15408) ([alesapin](https://github.com/alesapin)).
+* `clickhouse-test` supports SQL tests with [Jinja2](https://jinja.palletsprojects.com/en/3.0.x/templates/#synopsis) templates. [#26579](https://github.com/ClickHouse/ClickHouse/pull/26579) ([Vladimir C](https://github.com/vdimir)).
+* Add support for build with `clang-13`. This closes [#27705](https://github.com/ClickHouse/ClickHouse/issues/27705). [#27714](https://github.com/ClickHouse/ClickHouse/pull/27714) ([alexey-milovidov](https://github.com/alexey-milovidov)). [#27777](https://github.com/ClickHouse/ClickHouse/pull/27777) ([Sergei Semin](https://github.com/syominsergey))
+* Add CMake options to build with or without specific CPU instruction set. This is for [#17469](https://github.com/ClickHouse/ClickHouse/issues/17469) and [#27509](https://github.com/ClickHouse/ClickHouse/issues/27509). [#27508](https://github.com/ClickHouse/ClickHouse/pull/27508) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix linking of auxiliar programs when using dynamic libraries. [#26958](https://github.com/ClickHouse/ClickHouse/pull/26958) ([Raúl Marín](https://github.com/Algunenano)).
+* Update RocksDB to `2021-07-16` master. [#26411](https://github.com/ClickHouse/ClickHouse/pull/26411) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+
+### ClickHouse release v21.8, 2021-08-12
+
+#### Upgrade Notes
+* New version is using `Map` data type for system logs tables (`system.query_log`, `system.query_thread_log`, `system.processes`, `system.opentelemetry_span_log`). These tables will be auto-created with new data types. Virtual columns are created to support old queries. Closes [#18698](https://github.com/ClickHouse/ClickHouse/issues/18698). [#23934](https://github.com/ClickHouse/ClickHouse/pull/23934), [#25773](https://github.com/ClickHouse/ClickHouse/pull/25773) ([hexiaoting](https://github.com/hexiaoting), [sundy-li](https://github.com/sundy-li), [Maksim Kita](https://github.com/kitaisreal)). If you want to *downgrade* from version 21.8 to older versions, you will need to cleanup system tables with logs manually. Look at `/var/lib/clickhouse/data/system/*_log`.
+
+#### New Features
+
+* Add support for a part of SQL/JSON standard. [#24148](https://github.com/ClickHouse/ClickHouse/pull/24148) ([l1tsolaiki](https://github.com/l1tsolaiki), [Kseniia Sumarokova](https://github.com/kssenii)).
+* Collect common system metrics (in `system.asynchronous_metrics` and `system.asynchronous_metric_log`) on CPU usage, disk usage, memory usage, IO, network, files, load average, CPU frequencies, thermal sensors, EDAC counters, system uptime; also added metrics about the scheduling jitter and the time spent collecting the metrics. It works similar to `atop` in ClickHouse and allows access to monitoring data even if you have no additional tools installed. Close [#9430](https://github.com/ClickHouse/ClickHouse/issues/9430). [#24416](https://github.com/ClickHouse/ClickHouse/pull/24416) ([alexey-milovidov](https://github.com/alexey-milovidov), [Yegor Levankov](https://github.com/elevankoff)).
+* Add MaterializedPostgreSQL table engine and database engine. This database engine allows replicating a whole database or any subset of database tables. [#20470](https://github.com/ClickHouse/ClickHouse/pull/20470) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add new functions `leftPad()`, `rightPad()`, `leftPadUTF8()`, `rightPadUTF8()`. [#26075](https://github.com/ClickHouse/ClickHouse/pull/26075) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Add the `FIRST` keyword to the `ADD INDEX` command to be able to add the index at the beginning of the indices list. [#25904](https://github.com/ClickHouse/ClickHouse/pull/25904) ([xjewer](https://github.com/xjewer)).
+* Introduce `system.data_skipping_indices` table containing information about existing data skipping indices. Close [#7659](https://github.com/ClickHouse/ClickHouse/issues/7659). [#25693](https://github.com/ClickHouse/ClickHouse/pull/25693) ([Dmitry Novik](https://github.com/novikd)).
+* Add `bin`/`unbin` functions. [#25609](https://github.com/ClickHouse/ClickHouse/pull/25609) ([zhaoyu](https://github.com/zxc111)).
+* Support `Map` and `UInt128`, `Int128`, `UInt256`, `Int256` types in `mapAdd` and `mapSubtract` functions. [#25596](https://github.com/ClickHouse/ClickHouse/pull/25596) ([Ildus Kurbangaliev](https://github.com/ildus)).
+* Support `DISTINCT ON (columns)` expression, close [#25404](https://github.com/ClickHouse/ClickHouse/issues/25404). [#25589](https://github.com/ClickHouse/ClickHouse/pull/25589) ([Zijie Lu](https://github.com/TszKitLo40)).
+* Add an ability to reset a custom setting to default and remove it from the table's metadata. It allows rolling back the change without knowing the system/config's default.  Closes [#14449](https://github.com/ClickHouse/ClickHouse/issues/14449). [#17769](https://github.com/ClickHouse/ClickHouse/pull/17769) ([xjewer](https://github.com/xjewer)).
+* Render pipelines as graphs in Web UI if `EXPLAIN PIPELINE graph = 1` query is submitted. [#26067](https://github.com/ClickHouse/ClickHouse/pull/26067) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### Performance Improvements
+
+* Compile aggregate functions. Use option `compile_aggregate_expressions` to enable it. [#24789](https://github.com/ClickHouse/ClickHouse/pull/24789) ([Maksim Kita](https://github.com/kitaisreal)).
+* Improve latency of short queries that require reading from tables with many columns. [#26371](https://github.com/ClickHouse/ClickHouse/pull/26371) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Improvements
+
+* Use `Map` data type for system logs tables (`system.query_log`, `system.query_thread_log`, `system.processes`, `system.opentelemetry_span_log`). These tables will be auto-created with new data types. Virtual columns are created to support old queries. Closes [#18698](https://github.com/ClickHouse/ClickHouse/issues/18698). [#23934](https://github.com/ClickHouse/ClickHouse/pull/23934), [#25773](https://github.com/ClickHouse/ClickHouse/pull/25773) ([hexiaoting](https://github.com/hexiaoting), [sundy-li](https://github.com/sundy-li), [Maksim Kita](https://github.com/kitaisreal)).
+* For a dictionary with a complex key containing only one attribute, allow not wrapping the key expression in tuple for functions `dictGet`, `dictHas`. [#26130](https://github.com/ClickHouse/ClickHouse/pull/26130) ([Maksim Kita](https://github.com/kitaisreal)).
+* Implement function `bin`/`hex` from `AggregateFunction` states. [#26094](https://github.com/ClickHouse/ClickHouse/pull/26094) ([zhaoyu](https://github.com/zxc111)).
+* Support arguments of `UUID` type for `empty` and `notEmpty` functions. `UUID` is empty if it is all zeros (nil UUID). Closes [#3446](https://github.com/ClickHouse/ClickHouse/issues/3446). [#25974](https://github.com/ClickHouse/ClickHouse/pull/25974) ([zhaoyu](https://github.com/zxc111)).
+* Add support for `SET SQL_SELECT_LIMIT` in MySQL protocol. Closes [#17115](https://github.com/ClickHouse/ClickHouse/issues/17115). [#25972](https://github.com/ClickHouse/ClickHouse/pull/25972) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* More instrumentation for network interaction: add counters for recv/send bytes; add gauges for recvs/sends. Added missing documentation. Close [#5897](https://github.com/ClickHouse/ClickHouse/issues/5897). [#25962](https://github.com/ClickHouse/ClickHouse/pull/25962) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add setting `optimize_move_to_prewhere_if_final`. If query has `FINAL`, the optimization `move_to_prewhere` will be enabled only if both `optimize_move_to_prewhere` and `optimize_move_to_prewhere_if_final` are enabled. Closes [#8684](https://github.com/ClickHouse/ClickHouse/issues/8684). [#25940](https://github.com/ClickHouse/ClickHouse/pull/25940) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Allow complex quoted identifiers of JOINed tables. Close [#17861](https://github.com/ClickHouse/ClickHouse/issues/17861). [#25924](https://github.com/ClickHouse/ClickHouse/pull/25924) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add support for Unicode (e.g. Chinese, Cyrillic) components in `Nested` data types. Close [#25594](https://github.com/ClickHouse/ClickHouse/issues/25594). [#25923](https://github.com/ClickHouse/ClickHouse/pull/25923) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow `quantiles*` functions to work with `aggregate_functions_null_for_empty`. Close [#25892](https://github.com/ClickHouse/ClickHouse/issues/25892). [#25919](https://github.com/ClickHouse/ClickHouse/pull/25919) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow parameters for parametric aggregate functions to be arbitrary constant expressions (e.g., `1 + 2`), not just literals. It also allows using the query parameters (in parameterized queries like `{param:UInt8}`) inside parametric aggregate functions. Closes [#11607](https://github.com/ClickHouse/ClickHouse/issues/11607). [#25910](https://github.com/ClickHouse/ClickHouse/pull/25910) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Correctly throw the exception on the attempt to parse an invalid `Date`. Closes [#6481](https://github.com/ClickHouse/ClickHouse/issues/6481). [#25909](https://github.com/ClickHouse/ClickHouse/pull/25909) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support for multiple includes in configuration. It is possible to include users configuration, remote server configuration from multiple sources. Simply place `<include />` element with `from_zk`, `from_env` or `incl` attribute, and it will be replaced with the substitution. [#24404](https://github.com/ClickHouse/ClickHouse/pull/24404) ([nvartolomei](https://github.com/nvartolomei)).
+* Support for queries with a column named `"null"` (it must be specified in back-ticks or double quotes) and `ON CLUSTER`. Closes [#24035](https://github.com/ClickHouse/ClickHouse/issues/24035). [#25907](https://github.com/ClickHouse/ClickHouse/pull/25907) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support `LowCardinality`, `Decimal`, and `UUID` for `JSONExtract`. Closes [#24606](https://github.com/ClickHouse/ClickHouse/issues/24606). [#25900](https://github.com/ClickHouse/ClickHouse/pull/25900) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Convert history file from `readline` format to `replxx` format. [#25888](https://github.com/ClickHouse/ClickHouse/pull/25888) ([Azat Khuzhin](https://github.com/azat)).
+* Fix an issue which can lead to intersecting parts after `DROP PART` or background deletion of an empty part. [#25884](https://github.com/ClickHouse/ClickHouse/pull/25884) ([alesapin](https://github.com/alesapin)).
+* Better handling of lost parts for `ReplicatedMergeTree` tables. Fixes rare inconsistencies in `ReplicationQueue`. Fixes [#10368](https://github.com/ClickHouse/ClickHouse/issues/10368). [#25820](https://github.com/ClickHouse/ClickHouse/pull/25820) ([alesapin](https://github.com/alesapin)).
+* Allow starting clickhouse-client with unreadable working directory. [#25817](https://github.com/ClickHouse/ClickHouse/pull/25817) ([ianton-ru](https://github.com/ianton-ru)).
+* Fix "No available columns" error for `Merge` storage. [#25801](https://github.com/ClickHouse/ClickHouse/pull/25801) ([Azat Khuzhin](https://github.com/azat)).
+* MySQL Engine now supports the exchange of column comments between MySQL and ClickHouse. [#25795](https://github.com/ClickHouse/ClickHouse/pull/25795) ([Storozhuk Kostiantyn](https://github.com/sand6255)).
+* Fix inconsistent behaviour of `GROUP BY` constant on empty set. Closes [#6842](https://github.com/ClickHouse/ClickHouse/issues/6842). [#25786](https://github.com/ClickHouse/ClickHouse/pull/25786) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Cancel already running merges in partition on `DROP PARTITION` and `TRUNCATE` for `ReplicatedMergeTree`. Resolves [#17151](https://github.com/ClickHouse/ClickHouse/issues/17151). [#25684](https://github.com/ClickHouse/ClickHouse/pull/25684) ([tavplubix](https://github.com/tavplubix)).
+* Support ENUM` data type for MaterializeMySQL. [#25676](https://github.com/ClickHouse/ClickHouse/pull/25676) ([Storozhuk Kostiantyn](https://github.com/sand6255)).
+* Support materialized and aliased columns in JOIN, close [#13274](https://github.com/ClickHouse/ClickHouse/issues/13274). [#25634](https://github.com/ClickHouse/ClickHouse/pull/25634) ([Vladimir C](https://github.com/vdimir)).
+* Fix possible logical race condition between `ALTER TABLE ... DETACH` and background merges. [#25605](https://github.com/ClickHouse/ClickHouse/pull/25605) ([Azat Khuzhin](https://github.com/azat)).
+* Make `NetworkReceiveElapsedMicroseconds` metric to correctly include the time spent waiting for data from the client to `INSERT`. Close [#9958](https://github.com/ClickHouse/ClickHouse/issues/9958). [#25602](https://github.com/ClickHouse/ClickHouse/pull/25602) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support `TRUNCATE TABLE` for S3 and HDFS. Close [#25530](https://github.com/ClickHouse/ClickHouse/issues/25530). [#25550](https://github.com/ClickHouse/ClickHouse/pull/25550) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Support for dynamic reloading of config to change number of threads in pool for background jobs execution (merges, mutations, fetches). [#25548](https://github.com/ClickHouse/ClickHouse/pull/25548) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Allow extracting of non-string element as string using `JSONExtract`. This is for [#25414](https://github.com/ClickHouse/ClickHouse/issues/25414). [#25452](https://github.com/ClickHouse/ClickHouse/pull/25452) ([Amos Bird](https://github.com/amosbird)).
+* Support regular expression in `Database` argument for `StorageMerge`. Close [#776](https://github.com/ClickHouse/ClickHouse/issues/776). [#25064](https://github.com/ClickHouse/ClickHouse/pull/25064) ([flynn](https://github.com/ucasfl)).
+* Web UI: if the value looks like a URL, automatically generate a link. [#25965](https://github.com/ClickHouse/ClickHouse/pull/25965) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make `sudo service clickhouse-server start` to work on systems with `systemd` like Centos 8. Close [#14298](https://github.com/ClickHouse/ClickHouse/issues/14298). Close [#17799](https://github.com/ClickHouse/ClickHouse/issues/17799). [#25921](https://github.com/ClickHouse/ClickHouse/pull/25921) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### Bug Fixes
+
+* Fix incorrect `SET ROLE` in some cases. [#26707](https://github.com/ClickHouse/ClickHouse/pull/26707) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix potential `nullptr` dereference in window functions. Fix [#25276](https://github.com/ClickHouse/ClickHouse/issues/25276). [#26668](https://github.com/ClickHouse/ClickHouse/pull/26668) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fix incorrect function names of `groupBitmapAnd/Or/Xor`. Fix [#26557](https://github.com/ClickHouse/ClickHouse/pull/26557) ([Amos Bird](https://github.com/amosbird)).
+* Fix crash in RabbitMQ shutdown in case RabbitMQ setup was not started. Closes [#26504](https://github.com/ClickHouse/ClickHouse/issues/26504). [#26529](https://github.com/ClickHouse/ClickHouse/pull/26529) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix issues with `CREATE DICTIONARY` query if dictionary name or database name was quoted. Closes [#26491](https://github.com/ClickHouse/ClickHouse/issues/26491). [#26508](https://github.com/ClickHouse/ClickHouse/pull/26508) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix broken name resolution after rewriting column aliases. Fix [#26432](https://github.com/ClickHouse/ClickHouse/issues/26432). [#26475](https://github.com/ClickHouse/ClickHouse/pull/26475) ([Amos Bird](https://github.com/amosbird)).
+* Fix infinite non-joined block stream in `partial_merge_join` close [#26325](https://github.com/ClickHouse/ClickHouse/issues/26325). [#26374](https://github.com/ClickHouse/ClickHouse/pull/26374) ([Vladimir C](https://github.com/vdimir)).
+* Fix possible crash when login as dropped user. Fix [#26073](https://github.com/ClickHouse/ClickHouse/issues/26073). [#26363](https://github.com/ClickHouse/ClickHouse/pull/26363) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix `optimize_distributed_group_by_sharding_key` for multiple columns (leads to incorrect result w/ `optimize_skip_unused_shards=1`/`allow_nondeterministic_optimize_skip_unused_shards=1` and multiple columns in sharding key expression). [#26353](https://github.com/ClickHouse/ClickHouse/pull/26353) ([Azat Khuzhin](https://github.com/azat)).
+* `CAST` from `Date` to `DateTime` (or `DateTime64`) was not using the timezone of the `DateTime` type. It can also affect the comparison between `Date` and `DateTime`. Inference of the common type for `Date` and `DateTime` also was not using the corresponding timezone. It affected the results of function `if` and array construction. Closes [#24128](https://github.com/ClickHouse/ClickHouse/issues/24128). [#24129](https://github.com/ClickHouse/ClickHouse/pull/24129) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fixed rare bug in lost replica recovery that may cause replicas to diverge. [#26321](https://github.com/ClickHouse/ClickHouse/pull/26321) ([tavplubix](https://github.com/tavplubix)).
+* Fix zstd decompression in case there are escape sequences at the end of internal buffer. Closes [#26013](https://github.com/ClickHouse/ClickHouse/issues/26013). [#26314](https://github.com/ClickHouse/ClickHouse/pull/26314) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix logical error on join with totals, close [#26017](https://github.com/ClickHouse/ClickHouse/issues/26017). [#26250](https://github.com/ClickHouse/ClickHouse/pull/26250) ([Vladimir C](https://github.com/vdimir)).
+* Remove excessive newline in `thread_name` column in `system.stack_trace` table. Fix [#24124](https://github.com/ClickHouse/ClickHouse/issues/24124). [#26210](https://github.com/ClickHouse/ClickHouse/pull/26210) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `joinGet` with `LowCarinality` columns, close [#25993](https://github.com/ClickHouse/ClickHouse/issues/25993). [#26118](https://github.com/ClickHouse/ClickHouse/pull/26118) ([Vladimir C](https://github.com/vdimir)).
+* Fix possible crash in `pointInPolygon` if the setting `validate_polygons` is turned off. [#26113](https://github.com/ClickHouse/ClickHouse/pull/26113) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix throwing exception when iterate over non-existing remote directory. [#26087](https://github.com/ClickHouse/ClickHouse/pull/26087) ([ianton-ru](https://github.com/ianton-ru)).
+* Fix rare server crash because of `abort` in ZooKeeper client. Fixes [#25813](https://github.com/ClickHouse/ClickHouse/issues/25813). [#26079](https://github.com/ClickHouse/ClickHouse/pull/26079) ([alesapin](https://github.com/alesapin)).
+* Fix wrong thread count estimation for right subquery join in some cases. Close [#24075](https://github.com/ClickHouse/ClickHouse/issues/24075). [#26052](https://github.com/ClickHouse/ClickHouse/pull/26052) ([Vladimir C](https://github.com/vdimir)).
+* Fixed incorrect `sequence_id` in MySQL protocol packets that ClickHouse sends on exception during query execution. It might cause MySQL client to reset connection to ClickHouse server. Fixes [#21184](https://github.com/ClickHouse/ClickHouse/issues/21184). [#26051](https://github.com/ClickHouse/ClickHouse/pull/26051) ([tavplubix](https://github.com/tavplubix)).
+* Fix possible mismatched header when using normal projection with `PREWHERE`. Fix [#26020](https://github.com/ClickHouse/ClickHouse/issues/26020). [#26038](https://github.com/ClickHouse/ClickHouse/pull/26038) ([Amos Bird](https://github.com/amosbird)).
+* Fix formatting of type `Map` with integer keys to `JSON`. [#25982](https://github.com/ClickHouse/ClickHouse/pull/25982) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix possible deadlock during query profiler stack unwinding. Fix [#25968](https://github.com/ClickHouse/ClickHouse/issues/25968). [#25970](https://github.com/ClickHouse/ClickHouse/pull/25970) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix crash on call `dictGet()` with bad arguments. [#25913](https://github.com/ClickHouse/ClickHouse/pull/25913) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed `scram-sha-256` authentication for PostgreSQL engines. Closes [#24516](https://github.com/ClickHouse/ClickHouse/issues/24516). [#25906](https://github.com/ClickHouse/ClickHouse/pull/25906) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix extremely long backoff for background tasks when the background pool is full. Fixes [#25836](https://github.com/ClickHouse/ClickHouse/issues/25836). [#25893](https://github.com/ClickHouse/ClickHouse/pull/25893) ([alesapin](https://github.com/alesapin)).
+* Fix ARM exception handling with non default page size. Fixes [#25512](https://github.com/ClickHouse/ClickHouse/issues/25512), [#25044](https://github.com/ClickHouse/ClickHouse/issues/25044), [#24901](https://github.com/ClickHouse/ClickHouse/issues/24901), [#23183](https://github.com/ClickHouse/ClickHouse/issues/23183), [#20221](https://github.com/ClickHouse/ClickHouse/issues/20221), [#19703](https://github.com/ClickHouse/ClickHouse/issues/19703), [#19028](https://github.com/ClickHouse/ClickHouse/issues/19028), [#18391](https://github.com/ClickHouse/ClickHouse/issues/18391), [#18121](https://github.com/ClickHouse/ClickHouse/issues/18121), [#17994](https://github.com/ClickHouse/ClickHouse/issues/17994), [#12483](https://github.com/ClickHouse/ClickHouse/issues/12483). [#25854](https://github.com/ClickHouse/ClickHouse/pull/25854) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix sharding_key from column w/o function for `remote()` (before `select * from remote('127.1', system.one, dummy)` leads to `Unknown column: dummy, there are only columns .` error). [#25824](https://github.com/ClickHouse/ClickHouse/pull/25824) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed `Not found column ...` and `Missing column ...` errors when selecting from `MaterializeMySQL`. Fixes [#23708](https://github.com/ClickHouse/ClickHouse/issues/23708), [#24830](https://github.com/ClickHouse/ClickHouse/issues/24830), [#25794](https://github.com/ClickHouse/ClickHouse/issues/25794). [#25822](https://github.com/ClickHouse/ClickHouse/pull/25822) ([tavplubix](https://github.com/tavplubix)).
+* Fix `optimize_skip_unused_shards_rewrite_in` for non-UInt64 types (may select incorrect shards eventually or throw `Cannot infer type of an empty tuple` or `Function tuple requires at least one argument`). [#25798](https://github.com/ClickHouse/ClickHouse/pull/25798) ([Azat Khuzhin](https://github.com/azat)).
+* Fix rare bug with `DROP PART` query for `ReplicatedMergeTree` tables which can lead to error message `Unexpected merged part intersecting drop range`. [#25783](https://github.com/ClickHouse/ClickHouse/pull/25783) ([alesapin](https://github.com/alesapin)).
+* Fix bug in `TTL` with `GROUP BY` expression which refuses to execute `TTL` after first execution in part. [#25743](https://github.com/ClickHouse/ClickHouse/pull/25743) ([alesapin](https://github.com/alesapin)).
+* Allow StorageMerge to access tables with aliases. Closes [#6051](https://github.com/ClickHouse/ClickHouse/issues/6051). [#25694](https://github.com/ClickHouse/ClickHouse/pull/25694) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix slow dict join in some cases, close [#24209](https://github.com/ClickHouse/ClickHouse/issues/24209). [#25618](https://github.com/ClickHouse/ClickHouse/pull/25618) ([Vladimir C](https://github.com/vdimir)).
+* Fix `ALTER MODIFY COLUMN` of columns, which participates in TTL expressions. [#25554](https://github.com/ClickHouse/ClickHouse/pull/25554) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix assertion in `PREWHERE` with non-UInt8 type, close [#19589](https://github.com/ClickHouse/ClickHouse/issues/19589). [#25484](https://github.com/ClickHouse/ClickHouse/pull/25484) ([Vladimir C](https://github.com/vdimir)).
+* Fix some fuzzed msan crash. Fixes [#22517](https://github.com/ClickHouse/ClickHouse/issues/22517). [#26428](https://github.com/ClickHouse/ClickHouse/pull/26428) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Update `chown` cmd check in `clickhouse-server` docker entrypoint. It fixes error 'cluster pod restart failed (or timeout)' on kubernetes. [#26545](https://github.com/ClickHouse/ClickHouse/pull/26545) ([Ky Li](https://github.com/Kylinrix)).
+
+
+### ClickHouse release v21.7, 2021-07-09
+
+#### Backward Incompatible Change
+
+* Improved performance of queries with explicitly defined large sets. Added compatibility setting `legacy_column_name_of_tuple_literal`. It makes sense to set it to `true`, while doing rolling update of cluster from version lower than 21.7 to any higher version. Otherwise distributed queries with explicitly defined sets at `IN` clause may fail during update. [#25371](https://github.com/ClickHouse/ClickHouse/pull/25371) ([Anton Popov](https://github.com/CurtizJ)).
+* Forward/backward incompatible change of maximum buffer size in clickhouse-keeper (an experimental alternative to ZooKeeper). Better to do it now (before production), than later. [#25421](https://github.com/ClickHouse/ClickHouse/pull/25421) ([alesapin](https://github.com/alesapin)).
+
+#### New Feature
+
+* Support configuration in YAML format as alternative to XML. This closes [#3607](https://github.com/ClickHouse/ClickHouse/issues/3607). [#21858](https://github.com/ClickHouse/ClickHouse/pull/21858) ([BoloniniD](https://github.com/BoloniniD)).
+* Provides a way to restore replicated table when the data is (possibly) present, but the ZooKeeper metadata is lost. Resolves [#13458](https://github.com/ClickHouse/ClickHouse/issues/13458). [#13652](https://github.com/ClickHouse/ClickHouse/pull/13652) ([Mike Kot](https://github.com/myrrc)).
+* Support structs and maps in Arrow/Parquet/ORC and dictionaries in Arrow input/output formats. Present new setting `output_format_arrow_low_cardinality_as_dictionary`. [#24341](https://github.com/ClickHouse/ClickHouse/pull/24341) ([Kruglov Pavel](https://github.com/Avogar)).
+* Added support for `Array` type in dictionaries. [#25119](https://github.com/ClickHouse/ClickHouse/pull/25119) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added function `bitPositionsToArray`. Closes [#23792](https://github.com/ClickHouse/ClickHouse/issues/23792). Author [Kevin Wan] (@MaxWk). [#25394](https://github.com/ClickHouse/ClickHouse/pull/25394) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added function `dateName` to return names like 'Friday' or 'April'. Author [Daniil Kondratyev] (@dankondr). [#25372](https://github.com/ClickHouse/ClickHouse/pull/25372) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add `toJSONString` function to serialize columns to their JSON representations. [#25164](https://github.com/ClickHouse/ClickHouse/pull/25164) ([Amos Bird](https://github.com/amosbird)).
+* Now `query_log` has two new columns: `initial_query_start_time`, `initial_query_start_time_microsecond` that record the starting time of a distributed query if any. [#25022](https://github.com/ClickHouse/ClickHouse/pull/25022) ([Amos Bird](https://github.com/amosbird)).
+* Add aggregate function `segmentLengthSum`. [#24250](https://github.com/ClickHouse/ClickHouse/pull/24250) ([flynn](https://github.com/ucasfl)).
+* Add a new boolean setting `prefer_global_in_and_join` which defaults all IN/JOIN as GLOBAL IN/JOIN. [#23434](https://github.com/ClickHouse/ClickHouse/pull/23434) ([Amos Bird](https://github.com/amosbird)).
+* Support `ALTER DELETE` queries for `Join` table engine. [#23260](https://github.com/ClickHouse/ClickHouse/pull/23260) ([foolchi](https://github.com/foolchi)).
+* Add `quantileBFloat16` aggregate function as well as the corresponding `quantilesBFloat16` and `medianBFloat16`. It is very simple and fast quantile estimator with relative error not more than 0.390625%. This closes [#16641](https://github.com/ClickHouse/ClickHouse/issues/16641). [#23204](https://github.com/ClickHouse/ClickHouse/pull/23204) ([Ivan Novitskiy](https://github.com/RedClusive)).
+* Implement `sequenceNextNode()` function useful for `flow analysis`. [#19766](https://github.com/ClickHouse/ClickHouse/pull/19766) ([achimbab](https://github.com/achimbab)).
+
+#### Experimental Feature
+
+* Add support for virtual filesystem over HDFS. [#11058](https://github.com/ClickHouse/ClickHouse/pull/11058) ([overshov](https://github.com/overshov)) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Now clickhouse-keeper (an experimental alternative to ZooKeeper) supports ZooKeeper-like `digest` ACLs. [#24448](https://github.com/ClickHouse/ClickHouse/pull/24448) ([alesapin](https://github.com/alesapin)).
+
+#### Performance Improvement
+
+* Added optimization that transforms some functions to reading of subcolumns to reduce amount of read data. E.g., statement `col IS NULL` is transformed to reading of subcolumn `col.null`. Optimization can be enabled by setting `optimize_functions_to_subcolumns` which is currently off by default. [#24406](https://github.com/ClickHouse/ClickHouse/pull/24406) ([Anton Popov](https://github.com/CurtizJ)).
+* Rewrite more columns to possible alias expressions. This may enable better optimization, such as projections. [#24405](https://github.com/ClickHouse/ClickHouse/pull/24405) ([Amos Bird](https://github.com/amosbird)).
+* Index of type `bloom_filter` can be used for expressions with `hasAny` function with constant arrays. This closes: [#24291](https://github.com/ClickHouse/ClickHouse/issues/24291). [#24900](https://github.com/ClickHouse/ClickHouse/pull/24900) ([Vasily Nemkov](https://github.com/Enmk)).
+* Add exponential backoff to reschedule read attempt in case RabbitMQ queues are empty. (ClickHouse has support for importing data from RabbitMQ). Closes [#24340](https://github.com/ClickHouse/ClickHouse/issues/24340). [#24415](https://github.com/ClickHouse/ClickHouse/pull/24415) ([Kseniia Sumarokova](https://github.com/kssenii)).
+
+#### Improvement
+
+* Allow to limit bandwidth for replication. Add two Replicated\*MergeTree settings: `max_replicated_fetches_network_bandwidth` and `max_replicated_sends_network_bandwidth` which allows to limit maximum speed of replicated fetches/sends for table. Add two server-wide settings (in `default` user profile): `max_replicated_fetches_network_bandwidth_for_server` and `max_replicated_sends_network_bandwidth_for_server` which limit maximum speed of replication for all tables. The settings are not followed perfectly accurately. Turned off by default. Fixes [#1821](https://github.com/ClickHouse/ClickHouse/issues/1821). [#24573](https://github.com/ClickHouse/ClickHouse/pull/24573) ([alesapin](https://github.com/alesapin)).
+* Resource constraints and isolation for ODBC and Library bridges. Use separate `clickhouse-bridge` group and user for bridge processes. Set oom_score_adj so the bridges will be first subjects for OOM killer. Set set maximum RSS to 1 GiB. Closes [#23861](https://github.com/ClickHouse/ClickHouse/issues/23861). [#25280](https://github.com/ClickHouse/ClickHouse/pull/25280) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add standalone `clickhouse-keeper` symlink to the main `clickhouse` binary. Now it's possible to run coordination without the main clickhouse server. [#24059](https://github.com/ClickHouse/ClickHouse/pull/24059) ([alesapin](https://github.com/alesapin)).
+* Use global settings for query to `VIEW`. Fixed the behavior when queries to `VIEW` use local settings, that leads to errors if setting on `CREATE VIEW` and `SELECT` were different. As for now, `VIEW` won't use these modified settings, but you can still pass additional settings in `SETTINGS` section of `CREATE VIEW` query. Close [#20551](https://github.com/ClickHouse/ClickHouse/issues/20551). [#24095](https://github.com/ClickHouse/ClickHouse/pull/24095) ([Vladimir](https://github.com/vdimir)).
+* On server start, parts with incorrect partition ID would not be ever removed, but always detached. [#25070](https://github.com/ClickHouse/ClickHouse/issues/25070). [#25166](https://github.com/ClickHouse/ClickHouse/pull/25166) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Increase size of background schedule pool to 128 (`background_schedule_pool_size` setting). It allows avoiding replication queue hung on slow zookeeper connection. [#25072](https://github.com/ClickHouse/ClickHouse/pull/25072) ([alesapin](https://github.com/alesapin)).
+* Add merge tree setting `max_parts_to_merge_at_once` which limits the number of parts that can be merged in the background at once. Doesn't affect `OPTIMIZE FINAL` query. Fixes [#1820](https://github.com/ClickHouse/ClickHouse/issues/1820). [#24496](https://github.com/ClickHouse/ClickHouse/pull/24496) ([alesapin](https://github.com/alesapin)).
+* Allow `NOT IN` operator to be used in partition pruning. [#24894](https://github.com/ClickHouse/ClickHouse/pull/24894) ([Amos Bird](https://github.com/amosbird)).
+* Recognize IPv4 addresses like `127.0.1.1` as local. This is controversial and closes [#23504](https://github.com/ClickHouse/ClickHouse/issues/23504). Michael Filimonov will test this feature. [#24316](https://github.com/ClickHouse/ClickHouse/pull/24316) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* ClickHouse database created with MaterializeMySQL (it is an experimental feature) now contains all column comments from the MySQL database that materialized. [#25199](https://github.com/ClickHouse/ClickHouse/pull/25199) ([Storozhuk Kostiantyn](https://github.com/sand6255)).
+* Add settings (`connection_auto_close`/`connection_max_tries`/`connection_pool_size`) for MySQL storage engine. [#24146](https://github.com/ClickHouse/ClickHouse/pull/24146) ([Azat Khuzhin](https://github.com/azat)).
+* Improve startup time of Distributed engine. [#25663](https://github.com/ClickHouse/ClickHouse/pull/25663) ([Azat Khuzhin](https://github.com/azat)).
+* Improvement for Distributed tables. Drop replicas from dirname for internal_replication=true (allows INSERT into Distributed with cluster from any number of replicas, before only 15 replicas was supported, everything more will fail with ENAMETOOLONG while creating directory for async blocks). [#25513](https://github.com/ClickHouse/ClickHouse/pull/25513) ([Azat Khuzhin](https://github.com/azat)).
+* Added support `Interval` type for `LowCardinality`. It is needed for intermediate values of some expressions. Closes [#21730](https://github.com/ClickHouse/ClickHouse/issues/21730). [#25410](https://github.com/ClickHouse/ClickHouse/pull/25410) ([Vladimir](https://github.com/vdimir)).
+* Add `==` operator on time conditions for `sequenceMatch` and `sequenceCount` functions. For eg: sequenceMatch('(?1)(?t==1)(?2)')(time, data = 1, data = 2). [#25299](https://github.com/ClickHouse/ClickHouse/pull/25299) ([Christophe Kalenzaga](https://github.com/mga-chka)).
+* Add settings `http_max_fields`, `http_max_field_name_size`, `http_max_field_value_size`. [#25296](https://github.com/ClickHouse/ClickHouse/pull/25296) ([Ivan](https://github.com/abyss7)).
+* Add support for function `if` with `Decimal` and `Int` types on its branches. This closes [#20549](https://github.com/ClickHouse/ClickHouse/issues/20549). This closes [#10142](https://github.com/ClickHouse/ClickHouse/issues/10142). [#25283](https://github.com/ClickHouse/ClickHouse/pull/25283) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Update prompt in `clickhouse-client` and display a message when reconnecting. This closes [#10577](https://github.com/ClickHouse/ClickHouse/issues/10577). [#25281](https://github.com/ClickHouse/ClickHouse/pull/25281) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Correct memory tracking in aggregate function `topK`. This closes [#25259](https://github.com/ClickHouse/ClickHouse/issues/25259). [#25260](https://github.com/ClickHouse/ClickHouse/pull/25260) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix `topLevelDomain` for IDN hosts (i.e. `example.рф`), before it returns empty string for such hosts. [#25103](https://github.com/ClickHouse/ClickHouse/pull/25103) ([Azat Khuzhin](https://github.com/azat)).
+* Detect Linux kernel version at runtime (for worked nested epoll, that is required for `async_socket_for_remote`/`use_hedged_requests`, otherwise remote queries may stuck). [#25067](https://github.com/ClickHouse/ClickHouse/pull/25067) ([Azat Khuzhin](https://github.com/azat)).
+* For distributed query, when `optimize_skip_unused_shards=1`, allow to skip shard with condition like `(sharding key) IN (one-element-tuple)`. (Tuples with many elements were supported. Tuple with single element did not work because it is parsed as literal). [#24930](https://github.com/ClickHouse/ClickHouse/pull/24930) ([Amos Bird](https://github.com/amosbird)).
+* Improved log messages of S3 errors, no more double whitespaces in case of empty keys and buckets. [#24897](https://github.com/ClickHouse/ClickHouse/pull/24897) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Some queries require multi-pass semantic analysis. Try reusing built sets for `IN` in this case. [#24874](https://github.com/ClickHouse/ClickHouse/pull/24874) ([Amos Bird](https://github.com/amosbird)).
+* Respect `max_distributed_connections` for `insert_distributed_sync` (otherwise for huge clusters and sync insert it may run out of `max_thread_pool_size`). [#24754](https://github.com/ClickHouse/ClickHouse/pull/24754) ([Azat Khuzhin](https://github.com/azat)).
+* Avoid hiding errors like `Limit for rows or bytes to read exceeded` for scalar subqueries. [#24545](https://github.com/ClickHouse/ClickHouse/pull/24545) ([nvartolomei](https://github.com/nvartolomei)).
+* Make String-to-Int parser stricter so that `toInt64('+')` will throw. [#24475](https://github.com/ClickHouse/ClickHouse/pull/24475) ([Amos Bird](https://github.com/amosbird)).
+* If `SSD_CACHE` is created with DDL query, it can be created only inside `user_files` directory. [#24466](https://github.com/ClickHouse/ClickHouse/pull/24466) ([Maksim Kita](https://github.com/kitaisreal)).
+* PostgreSQL support for specifying non default schema for insert queries. Closes [#24149](https://github.com/ClickHouse/ClickHouse/issues/24149). [#24413](https://github.com/ClickHouse/ClickHouse/pull/24413) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix IPv6 addresses resolving (i.e. fixes `select * from remote('[::1]', system.one)`). [#24319](https://github.com/ClickHouse/ClickHouse/pull/24319) ([Azat Khuzhin](https://github.com/azat)).
+* Fix trailing whitespaces in FROM clause with subqueries in multiline mode, and also changes the output of the queries slightly in a more human friendly way. [#24151](https://github.com/ClickHouse/ClickHouse/pull/24151) ([Azat Khuzhin](https://github.com/azat)).
+* Improvement for Distributed tables. Add ability to split distributed batch on failures (i.e. due to memory limits, corruptions), under `distributed_directory_monitor_split_batch_on_failure` (OFF by default). [#23864](https://github.com/ClickHouse/ClickHouse/pull/23864) ([Azat Khuzhin](https://github.com/azat)).
+* Handle column name clashes for `Join` table engine. Closes [#20309](https://github.com/ClickHouse/ClickHouse/issues/20309). [#23769](https://github.com/ClickHouse/ClickHouse/pull/23769) ([Vladimir](https://github.com/vdimir)).
+* Display progress for `File` table engine in `clickhouse-local` and on INSERT query in `clickhouse-client` when data is passed to stdin. Closes [#18209](https://github.com/ClickHouse/ClickHouse/issues/18209). [#23656](https://github.com/ClickHouse/ClickHouse/pull/23656) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Bugfixes and improvements of `clickhouse-copier`. Allow to copy tables with different (but compatible schemas). Closes [#9159](https://github.com/ClickHouse/ClickHouse/issues/9159). Added test to copy ReplacingMergeTree. Closes [#22711](https://github.com/ClickHouse/ClickHouse/issues/22711). Support TTL on columns and Data Skipping Indices. It simply removes it to create internal Distributed table (underlying table will have TTL and skipping indices). Closes [#19384](https://github.com/ClickHouse/ClickHouse/issues/19384). Allow to copy MATERIALIZED and ALIAS columns. There are some cases in which it could be helpful (e.g. if this column is in PRIMARY KEY). Now it could be allowed by setting `allow_to_copy_alias_and_materialized_columns` property to true in task configuration. Closes [#9177](https://github.com/ClickHouse/ClickHouse/issues/9177). Closes [#11007] (https://github.com/ClickHouse/ClickHouse/issues/11007). Closes [#9514](https://github.com/ClickHouse/ClickHouse/issues/9514). Added a property `allow_to_drop_target_partitions` in task configuration to drop partition in original table before moving helping tables. Closes [#20957](https://github.com/ClickHouse/ClickHouse/issues/20957). Get rid of `OPTIMIZE DEDUPLICATE` query. This hack was needed, because `ALTER TABLE MOVE PARTITION` was retried many times and plain MergeTree tables don't have deduplication. Closes [#17966](https://github.com/ClickHouse/ClickHouse/issues/17966). Write progress to ZooKeeper node on path `task_path + /status` in JSON format. Closes [#20955](https://github.com/ClickHouse/ClickHouse/issues/20955). Support for ReplicatedTables without arguments. Closes [#24834](https://github.com/ClickHouse/ClickHouse/issues/24834) .[#23518](https://github.com/ClickHouse/ClickHouse/pull/23518) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Added sleep with backoff between read retries from S3. [#23461](https://github.com/ClickHouse/ClickHouse/pull/23461) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Respect `insert_allow_materialized_columns` (allows materialized columns) for INSERT into `Distributed` table. [#23349](https://github.com/ClickHouse/ClickHouse/pull/23349) ([Azat Khuzhin](https://github.com/azat)).
+* Add ability to push down LIMIT for distributed queries. [#23027](https://github.com/ClickHouse/ClickHouse/pull/23027) ([Azat Khuzhin](https://github.com/azat)).
+* Fix zero-copy replication with several S3 volumes (Fixes [#22679](https://github.com/ClickHouse/ClickHouse/issues/22679)). [#22864](https://github.com/ClickHouse/ClickHouse/pull/22864) ([ianton-ru](https://github.com/ianton-ru)).
+* Resolve the actual port number bound when a user requests any available port from the operating system to show it in the log message. [#25569](https://github.com/ClickHouse/ClickHouse/pull/25569) ([bnaecker](https://github.com/bnaecker)).
+* Fixed case, when sometimes conversion of postgres arrays resulted in String data type, not n-dimensional array, because `attndims` works incorrectly in some cases. Closes [#24804](https://github.com/ClickHouse/ClickHouse/issues/24804). [#25538](https://github.com/ClickHouse/ClickHouse/pull/25538) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix convertion of DateTime with timezone for MySQL, PostgreSQL, ODBC. Closes [#5057](https://github.com/ClickHouse/ClickHouse/issues/5057). [#25528](https://github.com/ClickHouse/ClickHouse/pull/25528) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Distinguish KILL MUTATION for different tables (fixes unexpected `Cancelled mutating parts` error). [#25025](https://github.com/ClickHouse/ClickHouse/pull/25025) ([Azat Khuzhin](https://github.com/azat)).
+* Allow to declare S3 disk at root of bucket (S3 virtual filesystem is an experimental feature under development). [#24898](https://github.com/ClickHouse/ClickHouse/pull/24898) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Enable reading of subcolumns (e.g. components of Tuples) for distributed tables. [#24472](https://github.com/ClickHouse/ClickHouse/pull/24472) ([Anton Popov](https://github.com/CurtizJ)).
+* A feature for MySQL compatibility protocol: make `user` function to return correct output. Closes [#25697](https://github.com/ClickHouse/ClickHouse/pull/25697). [#25697](https://github.com/ClickHouse/ClickHouse/pull/25697) ([sundyli](https://github.com/sundy-li)).
+
+#### Bug Fix
+
+* Improvement for backward compatibility. Use old modulo function version when used in partition key. Closes [#23508](https://github.com/ClickHouse/ClickHouse/issues/23508). [#24157](https://github.com/ClickHouse/ClickHouse/pull/24157) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix extremely rare bug on low-memory servers which can lead to the inability to perform merges without restart. Possibly fixes [#24603](https://github.com/ClickHouse/ClickHouse/issues/24603). [#24872](https://github.com/ClickHouse/ClickHouse/pull/24872) ([alesapin](https://github.com/alesapin)).
+* Fix extremely rare error `Tagging already tagged part` in replication queue during concurrent `alter move/replace partition`. Possibly fixes [#22142](https://github.com/ClickHouse/ClickHouse/issues/22142). [#24961](https://github.com/ClickHouse/ClickHouse/pull/24961) ([alesapin](https://github.com/alesapin)).
+* Fix potential crash when calculating aggregate function states by aggregation of aggregate function states of other aggregate functions (not a practical use case). See [#24523](https://github.com/ClickHouse/ClickHouse/issues/24523). [#25015](https://github.com/ClickHouse/ClickHouse/pull/25015) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed the behavior when query `SYSTEM RESTART REPLICA` or `SYSTEM SYNC REPLICA` does not finish. This was detected on server with extremely low amount of RAM. [#24457](https://github.com/ClickHouse/ClickHouse/pull/24457) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix bug which can lead to ZooKeeper client hung inside clickhouse-server. [#24721](https://github.com/ClickHouse/ClickHouse/pull/24721) ([alesapin](https://github.com/alesapin)).
+* If ZooKeeper connection was lost and replica was cloned after restoring the connection, its replication queue might contain outdated entries. Fixed failed assertion when replication queue contains intersecting virtual parts. It may rarely happen if some data part was lost. Print error in log instead of terminating. [#24777](https://github.com/ClickHouse/ClickHouse/pull/24777) ([tavplubix](https://github.com/tavplubix)).
+* Fix lost `WHERE` condition in expression-push-down optimization of query plan (setting `query_plan_filter_push_down = 1` by default). Fixes [#25368](https://github.com/ClickHouse/ClickHouse/issues/25368). [#25370](https://github.com/ClickHouse/ClickHouse/pull/25370) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug which can lead to intersecting parts after merges with TTL: `Part all_40_40_0 is covered by all_40_40_1 but should be merged into all_40_41_1. This shouldn't happen often.`. [#25549](https://github.com/ClickHouse/ClickHouse/pull/25549) ([alesapin](https://github.com/alesapin)).
+* On ZooKeeper connection loss `ReplicatedMergeTree` table might wait for background operations to complete before trying to reconnect. It's fixed, now background operations are stopped forcefully. [#25306](https://github.com/ClickHouse/ClickHouse/pull/25306) ([tavplubix](https://github.com/tavplubix)).
+* Fix error `Key expression contains comparison between inconvertible types` for queries with `ARRAY JOIN` in case if array is used in primary key. Fixes [#8247](https://github.com/ClickHouse/ClickHouse/issues/8247). [#25546](https://github.com/ClickHouse/ClickHouse/pull/25546) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix wrong totals for query `WITH TOTALS` and `WITH FILL`. Fixes [#20872](https://github.com/ClickHouse/ClickHouse/issues/20872). [#25539](https://github.com/ClickHouse/ClickHouse/pull/25539) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix data race when querying `system.clusters` while reloading the cluster configuration at the same time. [#25737](https://github.com/ClickHouse/ClickHouse/pull/25737) ([Amos Bird](https://github.com/amosbird)).
+* Fixed `No such file or directory` error on moving `Distributed` table between databases. Fixes [#24971](https://github.com/ClickHouse/ClickHouse/issues/24971). [#25667](https://github.com/ClickHouse/ClickHouse/pull/25667) ([tavplubix](https://github.com/tavplubix)).
+* `REPLACE PARTITION` might be ignored in rare cases if the source partition was empty. It's fixed. Fixes [#24869](https://github.com/ClickHouse/ClickHouse/issues/24869). [#25665](https://github.com/ClickHouse/ClickHouse/pull/25665) ([tavplubix](https://github.com/tavplubix)).
+* Fixed a bug in `Replicated` database engine that might rarely cause some replica to skip enqueued DDL query. [#24805](https://github.com/ClickHouse/ClickHouse/pull/24805) ([tavplubix](https://github.com/tavplubix)).
+* Fix null pointer dereference in `EXPLAIN AST` without query. [#25631](https://github.com/ClickHouse/ClickHouse/pull/25631) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix waiting of automatic dropping of empty parts. It could lead to full filling of background pool and stuck of replication. [#23315](https://github.com/ClickHouse/ClickHouse/pull/23315) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix restore of a table stored in S3 virtual filesystem (it is an experimental feature not ready for production). [#25601](https://github.com/ClickHouse/ClickHouse/pull/25601) ([ianton-ru](https://github.com/ianton-ru)).
+* Fix nullptr dereference in `Arrow` format when using `Decimal256`. Add `Decimal256` support for `Arrow` format. [#25531](https://github.com/ClickHouse/ClickHouse/pull/25531) ([Kruglov Pavel](https://github.com/Avogar)).
+* Fix excessive underscore before the names of the preprocessed configuration files. [#25431](https://github.com/ClickHouse/ClickHouse/pull/25431) ([Vitaly Baranov](https://github.com/vitlibar)).
+* A fix for `clickhouse-copier` tool: Fix segfault when sharding_key is absent in task config for copier. [#25419](https://github.com/ClickHouse/ClickHouse/pull/25419) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix `REPLACE` column transformer when used in DDL by correctly quoting the formated query. This fixes [#23925](https://github.com/ClickHouse/ClickHouse/issues/23925). [#25391](https://github.com/ClickHouse/ClickHouse/pull/25391) ([Amos Bird](https://github.com/amosbird)).
+* Fix the possibility of non-deterministic behaviour of the `quantileDeterministic` function and similar. This closes [#20480](https://github.com/ClickHouse/ClickHouse/issues/20480). [#25313](https://github.com/ClickHouse/ClickHouse/pull/25313) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support `SimpleAggregateFunction(LowCardinality)` for `SummingMergeTree`. Fixes [#25134](https://github.com/ClickHouse/ClickHouse/issues/25134). [#25300](https://github.com/ClickHouse/ClickHouse/pull/25300) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix logical error with exception message "Cannot sum Array/Tuple in min/maxMap". [#25298](https://github.com/ClickHouse/ClickHouse/pull/25298) ([Kruglov Pavel](https://github.com/Avogar)).
+* Fix error `Bad cast from type DB::ColumnLowCardinality to DB::ColumnVector<char8_t>` for queries where `LowCardinality` argument was used for IN (this bug appeared in 21.6). Fixes [#25187](https://github.com/ClickHouse/ClickHouse/issues/25187). [#25290](https://github.com/ClickHouse/ClickHouse/pull/25290) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix incorrect behaviour of `joinGetOrNull` with not-nullable columns. This fixes [#24261](https://github.com/ClickHouse/ClickHouse/issues/24261). [#25288](https://github.com/ClickHouse/ClickHouse/pull/25288) ([Amos Bird](https://github.com/amosbird)).
+* Fix incorrect behaviour and UBSan report in big integers. In previous versions `CAST(1e19 AS UInt128)` returned zero. [#25279](https://github.com/ClickHouse/ClickHouse/pull/25279) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed an error which occurred while inserting a subset of columns using CSVWithNames format. Fixes [#25129](https://github.com/ClickHouse/ClickHouse/issues/25129). [#25169](https://github.com/ClickHouse/ClickHouse/pull/25169) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Do not use table's projection for `SELECT` with `FINAL`. It is not supported yet. [#25163](https://github.com/ClickHouse/ClickHouse/pull/25163) ([Amos Bird](https://github.com/amosbird)).
+* Fix possible parts loss after updating up to 21.5 in case table used `UUID` in partition key. (It is not recommended to use `UUID` in partition key). Fixes [#25070](https://github.com/ClickHouse/ClickHouse/issues/25070). [#25127](https://github.com/ClickHouse/ClickHouse/pull/25127) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix crash in query with cross join and `joined_subquery_requires_alias = 0`. Fixes [#24011](https://github.com/ClickHouse/ClickHouse/issues/24011). [#25082](https://github.com/ClickHouse/ClickHouse/pull/25082) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug with constant maps in mapContains function that lead to error `empty column was returned by function mapContains`. Closes [#25077](https://github.com/ClickHouse/ClickHouse/issues/25077). [#25080](https://github.com/ClickHouse/ClickHouse/pull/25080) ([Kruglov Pavel](https://github.com/Avogar)).
+* Remove possibility to create tables with columns referencing themselves like `a UInt32 ALIAS a + 1` or `b UInt32 MATERIALIZED b`. Fixes [#24910](https://github.com/ClickHouse/ClickHouse/issues/24910), [#24292](https://github.com/ClickHouse/ClickHouse/issues/24292). [#25059](https://github.com/ClickHouse/ClickHouse/pull/25059) ([alesapin](https://github.com/alesapin)).
+* Fix wrong result when using aggregate projection with *not empty* `GROUP BY` key to execute query with `GROUP BY` by *empty* key. [#25055](https://github.com/ClickHouse/ClickHouse/pull/25055) ([Amos Bird](https://github.com/amosbird)).
+* Fix serialization of splitted nested messages in Protobuf format. This PR fixes [#24647](https://github.com/ClickHouse/ClickHouse/issues/24647). [#25000](https://github.com/ClickHouse/ClickHouse/pull/25000) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix limit/offset settings for distributed queries (ignore on the remote nodes). [#24940](https://github.com/ClickHouse/ClickHouse/pull/24940) ([Azat Khuzhin](https://github.com/azat)).
+* Fix possible heap-buffer-overflow in `Arrow` format. [#24922](https://github.com/ClickHouse/ClickHouse/pull/24922) ([Kruglov Pavel](https://github.com/Avogar)).
+* Fixed possible error 'Cannot read from istream at offset 0' when reading a file from DiskS3 (S3 virtual filesystem is an experimental feature under development that should not be used in production). [#24885](https://github.com/ClickHouse/ClickHouse/pull/24885) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fix "Missing columns" exception when joining Distributed Materialized View. [#24870](https://github.com/ClickHouse/ClickHouse/pull/24870) ([Azat Khuzhin](https://github.com/azat)).
+* Allow `NULL` values in postgresql compatibility protocol. Closes [#22622](https://github.com/ClickHouse/ClickHouse/issues/22622). [#24857](https://github.com/ClickHouse/ClickHouse/pull/24857) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix bug when exception `Mutation was killed` can be thrown to the client on mutation wait when mutation not loaded into memory yet. [#24809](https://github.com/ClickHouse/ClickHouse/pull/24809) ([alesapin](https://github.com/alesapin)).
+* Fixed bug in deserialization of random generator state with might cause some data types such as `AggregateFunction(groupArraySample(N), T))` to behave in a non-deterministic way. [#24538](https://github.com/ClickHouse/ClickHouse/pull/24538) ([tavplubix](https://github.com/tavplubix)).
+* Disallow building uniqXXXXStates of other aggregation states. [#24523](https://github.com/ClickHouse/ClickHouse/pull/24523) ([Raúl Marín](https://github.com/Algunenano)). Then allow it back by actually eliminating the root cause of the related issue. ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix usage of tuples in `CREATE .. AS SELECT` queries. [#24464](https://github.com/ClickHouse/ClickHouse/pull/24464) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix computation of total bytes in `Buffer` table. In current ClickHouse version total_writes.bytes counter decreases too much during the buffer flush. It leads to counter overflow and totalBytes return something around 17.44 EB some time after the flush. [#24450](https://github.com/ClickHouse/ClickHouse/pull/24450) ([DimasKovas](https://github.com/DimasKovas)).
+* Fix incorrect information about the monotonicity of toWeek function. This fixes [#24422](https://github.com/ClickHouse/ClickHouse/issues/24422) . This bug was introduced in https://github.com/ClickHouse/ClickHouse/pull/5212 , and was exposed later by smarter partition pruner. [#24446](https://github.com/ClickHouse/ClickHouse/pull/24446) ([Amos Bird](https://github.com/amosbird)).
+* When user authentication is managed by LDAP. Fixed potential deadlock that can happen during LDAP role (re)mapping, when LDAP group is mapped to a nonexistent local role. [#24431](https://github.com/ClickHouse/ClickHouse/pull/24431) ([Denis Glazachev](https://github.com/traceon)).
+* In "multipart/form-data" message consider the CRLF preceding a boundary as part of it. Fixes [#23905](https://github.com/ClickHouse/ClickHouse/issues/23905). [#24399](https://github.com/ClickHouse/ClickHouse/pull/24399) ([Ivan](https://github.com/abyss7)).
+* Fix drop partition with intersect fake parts. In rare cases there might be parts with mutation version greater than current block number. [#24321](https://github.com/ClickHouse/ClickHouse/pull/24321) ([Amos Bird](https://github.com/amosbird)).
+* Fixed a bug in moving Materialized View from Ordinary to Atomic database (`RENAME TABLE` query). Now inner table is moved to new database together with Materialized View. Fixes [#23926](https://github.com/ClickHouse/ClickHouse/issues/23926). [#24309](https://github.com/ClickHouse/ClickHouse/pull/24309) ([tavplubix](https://github.com/tavplubix)).
+* Allow empty HTTP headers. Fixes [#23901](https://github.com/ClickHouse/ClickHouse/issues/23901). [#24285](https://github.com/ClickHouse/ClickHouse/pull/24285) ([Ivan](https://github.com/abyss7)).
+* Correct processing of mutations (ALTER UPDATE/DELETE) in Memory tables. Closes [#24274](https://github.com/ClickHouse/ClickHouse/issues/24274). [#24275](https://github.com/ClickHouse/ClickHouse/pull/24275) ([flynn](https://github.com/ucasfl)).
+* Make column LowCardinality property in JOIN output the same as in the input, close [#23351](https://github.com/ClickHouse/ClickHouse/issues/23351), close [#20315](https://github.com/ClickHouse/ClickHouse/issues/20315). [#24061](https://github.com/ClickHouse/ClickHouse/pull/24061) ([Vladimir](https://github.com/vdimir)).
+* A fix for Kafka tables. Fix the bug in failover behavior when Engine = Kafka was not able to start consumption if the same consumer had an empty assignment previously. Closes [#21118](https://github.com/ClickHouse/ClickHouse/issues/21118). [#21267](https://github.com/ClickHouse/ClickHouse/pull/21267) ([filimonov](https://github.com/filimonov)).
+
+#### Build/Testing/Packaging Improvement
+
+* Add `darwin-aarch64` (Mac M1 / Apple Silicon) builds in CI [#25560](https://github.com/ClickHouse/ClickHouse/pull/25560) ([Ivan](https://github.com/abyss7)) and put the links to the docs and website ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Adds cross-platform embedding of binary resources into executables. It works on Illumos. [#25146](https://github.com/ClickHouse/ClickHouse/pull/25146) ([bnaecker](https://github.com/bnaecker)).
+* Add join related options to stress tests to improve fuzzing. [#25200](https://github.com/ClickHouse/ClickHouse/pull/25200) ([Vladimir](https://github.com/vdimir)).
+* Enable build with s3 module in osx [#25217](https://github.com/ClickHouse/ClickHouse/issues/25217). [#25218](https://github.com/ClickHouse/ClickHouse/pull/25218) ([kevin wan](https://github.com/MaxWk)).
+* Add integration test cases to cover JDBC bridge. [#25047](https://github.com/ClickHouse/ClickHouse/pull/25047) ([Zhichun Wu](https://github.com/zhicwu)).
+* Integration tests configuration has special treatment for dictionaries. Removed remaining dictionaries manual setup. [#24728](https://github.com/ClickHouse/ClickHouse/pull/24728) ([Ilya Yatsishin](https://github.com/qoega)).
+* Add libfuzzer tests for YAMLParser class. [#24480](https://github.com/ClickHouse/ClickHouse/pull/24480) ([BoloniniD](https://github.com/BoloniniD)).
+* Ubuntu 20.04 is now used to run integration tests, docker-compose version used to run integration tests is updated to 1.28.2. Environment variables now take effect on docker-compose. Rework test_dictionaries_all_layouts_separate_sources to allow parallel run. [#20393](https://github.com/ClickHouse/ClickHouse/pull/20393) ([Ilya Yatsishin](https://github.com/qoega)).
+* Fix TOCTOU error in installation script. [#25277](https://github.com/ClickHouse/ClickHouse/pull/25277) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+
+### ClickHouse release 21.6, 2021-06-05
+
+#### Backward Incompatible Change
+* uniqState / uniqHLL12State / uniqCombinedState / uniqCombined64State produce incompatible states with `UUID` type. [#33607](https://github.com/ClickHouse/ClickHouse/issues/33607).
+
+#### Upgrade Notes
+
+* `zstd` compression library is updated to v1.5.0. You may get messages about "checksum does not match" in replication. These messages are expected due to update of compression algorithm and you can ignore them. These messages are informational and do not indicate any kinds of undesired behaviour.
+* The setting `compile_expressions` is enabled by default. Although it has been heavily tested on variety of scenarios, if you find some undesired behaviour on your servers, you can try turning this setting off.
+* Values of `UUID` type cannot be compared with integer. For example, instead of writing `uuid != 0` type `uuid != '00000000-0000-0000-0000-000000000000'`.
+
+#### New Feature
+
+* Add Postgres-like cast operator (`::`). E.g.: `[1, 2]::Array(UInt8)`, `0.1::Decimal(4, 4)`, `number::UInt16`. [#23871](https://github.com/ClickHouse/ClickHouse/pull/23871) ([Anton Popov](https://github.com/CurtizJ)).
+* Make big integers production ready. Add support for `UInt128` data type. Fix known issues with the `Decimal256` data type. Support big integers in dictionaries. Support `gcd`/`lcm` functions for big integers. Support big integers in array search and conditional functions. Support `LowCardinality(UUID)`. Support big integers in `generateRandom` table function and `clickhouse-obfuscator`. Fix error with returning `UUID` from scalar subqueries. This fixes [#7834](https://github.com/ClickHouse/ClickHouse/issues/7834). This fixes [#23936](https://github.com/ClickHouse/ClickHouse/issues/23936). This fixes [#4176](https://github.com/ClickHouse/ClickHouse/issues/4176). This fixes [#24018](https://github.com/ClickHouse/ClickHouse/issues/24018). Backward incompatible change: values of `UUID` type cannot be compared with integer. For example, instead of writing `uuid != 0` type `uuid != '00000000-0000-0000-0000-000000000000'`. [#23631](https://github.com/ClickHouse/ClickHouse/pull/23631) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support `Array` data type for inserting and selecting data in `Arrow`, `Parquet` and `ORC` formats. [#21770](https://github.com/ClickHouse/ClickHouse/pull/21770) ([taylor12805](https://github.com/taylor12805)).
+* Implement table comments. Closes [#23225](https://github.com/ClickHouse/ClickHouse/issues/23225). [#23548](https://github.com/ClickHouse/ClickHouse/pull/23548) ([flynn](https://github.com/ucasFL)).
+* Support creating dictionaries with DDL queries in `clickhouse-local`. Closes [#22354](https://github.com/ClickHouse/ClickHouse/issues/22354). Added support for `DETACH DICTIONARY PERMANENTLY`. Added support for `EXCHANGE DICTIONARIES` for `Atomic` database engine. Added support for moving dictionaries between databases using `RENAME DICTIONARY`. [#23436](https://github.com/ClickHouse/ClickHouse/pull/23436) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add aggregate function `uniqTheta` to support [Theta Sketch](https://datasketches.apache.org/docs/Theta/ThetaSketchFramework.html) in ClickHouse. [#23894](https://github.com/ClickHouse/ClickHouse/pull/23894). [#22609](https://github.com/ClickHouse/ClickHouse/pull/22609) ([Ping Yu](https://github.com/pingyu)).
+* Add function `splitByRegexp`. [#24077](https://github.com/ClickHouse/ClickHouse/pull/24077) ([abel-cheng](https://github.com/abel-cheng)).
+* Add function `arrayProduct` which accept an array as the parameter, and return the product of all the elements in array. Closes [#21613](https://github.com/ClickHouse/ClickHouse/issues/21613). [#23782](https://github.com/ClickHouse/ClickHouse/pull/23782) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add `thread_name` column in `system.stack_trace`. This closes [#23256](https://github.com/ClickHouse/ClickHouse/issues/23256). [#24124](https://github.com/ClickHouse/ClickHouse/pull/24124) ([abel-cheng](https://github.com/abel-cheng)).
+* If `insert_null_as_default` = 1, insert default values instead of NULL in `INSERT ... SELECT` and `INSERT ... SELECT ... UNION ALL ...` queries. Closes [#22832](https://github.com/ClickHouse/ClickHouse/issues/22832). [#23524](https://github.com/ClickHouse/ClickHouse/pull/23524) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add support for progress indication in `clickhouse-local` with `--progress` option. [#23196](https://github.com/ClickHouse/ClickHouse/pull/23196) ([Egor Savin](https://github.com/Amesaru)).
+* Add support for HTTP compression (determined by `Content-Encoding` HTTP header) in `http` dictionary source. This fixes [#8912](https://github.com/ClickHouse/ClickHouse/issues/8912). [#23946](https://github.com/ClickHouse/ClickHouse/pull/23946) ([FArthur-cmd](https://github.com/FArthur-cmd)).
+* Added `SYSTEM QUERY RELOAD MODEL`, `SYSTEM QUERY RELOAD MODELS`. Closes [#18722](https://github.com/ClickHouse/ClickHouse/issues/18722). [#23182](https://github.com/ClickHouse/ClickHouse/pull/23182) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add setting `json` (boolean, 0 by default) for `EXPLAIN PLAN` query. When enabled, query output will be a single `JSON` row. It is recommended to use `TSVRaw` format to avoid unnecessary escaping. [#23082](https://github.com/ClickHouse/ClickHouse/pull/23082) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Add setting `indexes` (boolean, disabled by default) to `EXPLAIN PIPELINE` query. When enabled, shows used indexes, number of filtered parts and granules for every index applied. Supported for `MergeTree*` tables. [#22352](https://github.com/ClickHouse/ClickHouse/pull/22352) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* LDAP: implemented user DN detection functionality to use when mapping Active Directory groups to ClickHouse roles. [#22228](https://github.com/ClickHouse/ClickHouse/pull/22228) ([Denis Glazachev](https://github.com/traceon)).
+* New aggregate function `deltaSumTimestamp` for summing the difference between consecutive rows while maintaining ordering during merge by storing timestamps. [#21888](https://github.com/ClickHouse/ClickHouse/pull/21888) ([Russ Frank](https://github.com/rf)).
+* Added less secure IMDS credentials provider for S3 which works under docker correctly. [#21852](https://github.com/ClickHouse/ClickHouse/pull/21852) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Add back `indexHint` function. This is for [#21238](https://github.com/ClickHouse/ClickHouse/issues/21238). This reverts [#9542](https://github.com/ClickHouse/ClickHouse/pull/9542). This fixes [#9540](https://github.com/ClickHouse/ClickHouse/issues/9540). [#21304](https://github.com/ClickHouse/ClickHouse/pull/21304) ([Amos Bird](https://github.com/amosbird)).
+
+#### Experimental Feature
+
+* Add `PROJECTION` support for `MergeTree*` tables. [#20202](https://github.com/ClickHouse/ClickHouse/pull/20202) ([Amos Bird](https://github.com/amosbird)).
+
+#### Performance Improvement
+
+* Enable `compile_expressions` setting by default. When this setting enabled, compositions of simple functions and operators will be compiled to native code with LLVM at runtime. [#8482](https://github.com/ClickHouse/ClickHouse/pull/8482) ([Maksim Kita](https://github.com/kitaisreal), [alexey-milovidov](https://github.com/alexey-milovidov)). Note: if you feel in trouble, turn this option off.
+* Update `re2` library. Performance of regular expressions matching is improved. Also this PR adds compatibility with gcc-11. [#24196](https://github.com/ClickHouse/ClickHouse/pull/24196) ([Raúl Marín](https://github.com/Algunenano)).
+* ORC input format reading by stripe instead of reading entire table into memory by once which is cost memory when file size is huge. [#23102](https://github.com/ClickHouse/ClickHouse/pull/23102) ([Chao Ma](https://github.com/godliness)).
+* Fusion of aggregate functions `sum`, `count` and `avg` in a query into single aggregate function. The optimization is controlled with the `optimize_fuse_sum_count_avg` setting. This is implemented with a new aggregate function `sumCount`. This function returns a tuple of two fields: `sum` and `count`. [#21337](https://github.com/ClickHouse/ClickHouse/pull/21337) ([hexiaoting](https://github.com/hexiaoting)).
+* Update `zstd` to v1.5.0. The performance of compression is improved for single digits percentage. [#24135](https://github.com/ClickHouse/ClickHouse/pull/24135) ([Raúl Marín](https://github.com/Algunenano)). Note: you may get messages about "checksum does not match" in replication. These messages are expected due to update of compression algorithm and you can ignore them.
+* Improved performance of `Buffer` tables: do not acquire lock for total_bytes/total_rows for `Buffer` engine. [#24066](https://github.com/ClickHouse/ClickHouse/pull/24066) ([Azat Khuzhin](https://github.com/azat)).
+* Preallocate support for hashed/sparse_hashed dictionaries is returned. [#23979](https://github.com/ClickHouse/ClickHouse/pull/23979) ([Azat Khuzhin](https://github.com/azat)).
+* Enable `async_socket_for_remote` by default (lower amount of threads in querying Distributed tables with large fanout). [#23683](https://github.com/ClickHouse/ClickHouse/pull/23683) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+
+#### Improvement
+
+* Add `_partition_value` virtual column to MergeTree table family. It can be used to prune partition in a deterministic way. It's needed to implement partition matcher for mutations. [#23673](https://github.com/ClickHouse/ClickHouse/pull/23673) ([Amos Bird](https://github.com/amosbird)).
+* Added `region` parameter for S3 storage and disk. [#23846](https://github.com/ClickHouse/ClickHouse/pull/23846) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Allow configuring different log levels for different logging channels. Closes [#19569](https://github.com/ClickHouse/ClickHouse/issues/19569). [#23857](https://github.com/ClickHouse/ClickHouse/pull/23857) ([filimonov](https://github.com/filimonov)).
+* Keep default timezone on `DateTime` operations if it was not provided explicitly. For example, if you add one second to a value of `DateTime` type without timezone it will remain `DateTime` without timezone. In previous versions the value of default timezone was placed to the returned data type explicitly so it becomes DateTime('something'). This closes [#4854](https://github.com/ClickHouse/ClickHouse/issues/4854). [#23392](https://github.com/ClickHouse/ClickHouse/pull/23392) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow user to specify empty string instead of database name for `MySQL` storage. Default database will be used for queries. In previous versions it was working for SELECT queries and not support for INSERT was also added. This closes [#19281](https://github.com/ClickHouse/ClickHouse/issues/19281). This can be useful working with `Sphinx` or other MySQL-compatible foreign databases. [#23319](https://github.com/ClickHouse/ClickHouse/pull/23319) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `quantile(s)TDigest`. Added special handling of singleton centroids according to tdunning/t-digest 3.2+. Also a bug with over-compression of centroids in implementation of earlier version of the algorithm was fixed. [#23314](https://github.com/ClickHouse/ClickHouse/pull/23314) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Function `now64` now supports optional timezone argument. [#24091](https://github.com/ClickHouse/ClickHouse/pull/24091) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fix the case when a progress bar in interactive mode in clickhouse-client that appear in the middle of the data may rewrite some parts of visible data in terminal. This closes [#19283](https://github.com/ClickHouse/ClickHouse/issues/19283). [#23050](https://github.com/ClickHouse/ClickHouse/pull/23050) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix crash when memory allocation fails in simdjson. https://github.com/simdjson/simdjson/pull/1567 . Mark as improvement because it's a very rare bug. [#24147](https://github.com/ClickHouse/ClickHouse/pull/24147) ([Amos Bird](https://github.com/amosbird)).
+* Preserve dictionaries until storage shutdown (this will avoid possible `external dictionary 'DICT' not found` errors at server shutdown during final flush of the `Buffer` engine). [#24068](https://github.com/ClickHouse/ClickHouse/pull/24068) ([Azat Khuzhin](https://github.com/azat)).
+* Flush `Buffer` tables before shutting down tables (within one database), to avoid discarding blocks due to underlying table had been already detached (and `Destination table default.a_data_01870 doesn't exist. Block of data is discarded` error in the log). [#24067](https://github.com/ClickHouse/ClickHouse/pull/24067) ([Azat Khuzhin](https://github.com/azat)).
+* Now `prefer_column_name_to_alias = 1` will also favor column names for `group by`, `having` and `order by`. This fixes [#23882](https://github.com/ClickHouse/ClickHouse/issues/23882). [#24022](https://github.com/ClickHouse/ClickHouse/pull/24022) ([Amos Bird](https://github.com/amosbird)).
+* Add support for `ORDER BY WITH FILL` with `DateTime64`. [#24016](https://github.com/ClickHouse/ClickHouse/pull/24016) ([kevin wan](https://github.com/MaxWk)).
+* Enable `DateTime64` to be a version column in `ReplacingMergeTree`. [#23992](https://github.com/ClickHouse/ClickHouse/pull/23992) ([kevin wan](https://github.com/MaxWk)).
+* Log information about OS name, kernel version and CPU architecture on server startup. [#23988](https://github.com/ClickHouse/ClickHouse/pull/23988) ([Azat Khuzhin](https://github.com/azat)).
+* Support specifying table schema for `postgresql` dictionary source. Closes [#23958](https://github.com/ClickHouse/ClickHouse/issues/23958). [#23980](https://github.com/ClickHouse/ClickHouse/pull/23980) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add hints for names of `Enum` elements (suggest names in case of typos). Closes [#17112](https://github.com/ClickHouse/ClickHouse/issues/17112). [#23919](https://github.com/ClickHouse/ClickHouse/pull/23919) ([flynn](https://github.com/ucasFL)).
+* Measure found rate (the percentage for which the value was found) for dictionaries (see `found_rate` in `system.dictionaries`). [#23916](https://github.com/ClickHouse/ClickHouse/pull/23916) ([Azat Khuzhin](https://github.com/azat)).
+* Allow to add specific queue settings via table settng `rabbitmq_queue_settings_list`. (Closes [#23737](https://github.com/ClickHouse/ClickHouse/issues/23737) and [#23918](https://github.com/ClickHouse/ClickHouse/issues/23918)). Allow user to control all RabbitMQ setup: if table setting `rabbitmq_queue_consume` is set to `1` - RabbitMQ table engine will only connect to specified queue and will not perform any RabbitMQ consumer-side setup like declaring exchange, queues, bindings. (Closes [#21757](https://github.com/ClickHouse/ClickHouse/issues/21757)). Add proper cleanup when RabbitMQ table is dropped - delete queues, which the table has declared and all bound exchanges - if they were created by the table. [#23887](https://github.com/ClickHouse/ClickHouse/pull/23887) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add `broken_data_files`/`broken_data_compressed_bytes` into `system.distribution_queue`. Add metric for number of files for asynchronous insertion into Distributed tables that has been marked as broken (`BrokenDistributedFilesToInsert`). [#23885](https://github.com/ClickHouse/ClickHouse/pull/23885) ([Azat Khuzhin](https://github.com/azat)).
+* Querying `system.tables` does not go to ZooKeeper anymore. [#23793](https://github.com/ClickHouse/ClickHouse/pull/23793) ([Fuwang Hu](https://github.com/fuwhu)).
+* Respect `lock_acquire_timeout_for_background_operations` for `OPTIMIZE` queries. [#23623](https://github.com/ClickHouse/ClickHouse/pull/23623) ([Azat Khuzhin](https://github.com/azat)).
+* Possibility to change `S3` disk settings in runtime via new `SYSTEM RESTART DISK` SQL command. [#23429](https://github.com/ClickHouse/ClickHouse/pull/23429) ([Pavel Kovalenko](https://github.com/Jokser)).
+* If user applied a misconfiguration by mistakenly setting `max_distributed_connections` to value zero, every query to a `Distributed` table will throw exception with a message containing "logical error". But it's really an expected behaviour, not a logical error, so the exception message was slightly incorrect. It also triggered checks in our CI enviroment that ensures that no logical errors ever happen. Instead we will treat `max_distributed_connections` misconfigured to zero as the minimum possible value (one). [#23348](https://github.com/ClickHouse/ClickHouse/pull/23348) ([Azat Khuzhin](https://github.com/azat)).
+* Disable `min_bytes_to_use_mmap_io` by default. [#23322](https://github.com/ClickHouse/ClickHouse/pull/23322) ([Azat Khuzhin](https://github.com/azat)).
+* Support `LowCardinality` nullability with `join_use_nulls`, close [#15101](https://github.com/ClickHouse/ClickHouse/issues/15101). [#23237](https://github.com/ClickHouse/ClickHouse/pull/23237) ([vdimir](https://github.com/vdimir)).
+* Added possibility to restore `MergeTree` parts to `detached` directory for `S3` disk. [#23112](https://github.com/ClickHouse/ClickHouse/pull/23112) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Retries on HTTP connection drops in S3. [#22988](https://github.com/ClickHouse/ClickHouse/pull/22988) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Add settings `external_storage_max_read_rows` and `external_storage_max_read_rows` for MySQL table engine, dictionary source and MaterializeMySQL minor data fetches. [#22697](https://github.com/ClickHouse/ClickHouse/pull/22697) ([TCeason](https://github.com/TCeason)).
+* `MaterializeMySQL` (experimental feature): Previously, MySQL 5.7.9 was not supported due to SQL incompatibility. Now leave MySQL parameter verification to the MaterializeMySQL. [#23413](https://github.com/ClickHouse/ClickHouse/pull/23413) ([TCeason](https://github.com/TCeason)).
+* Enable reading of subcolumns for distributed tables. [#24472](https://github.com/ClickHouse/ClickHouse/pull/24472) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix usage of tuples in `CREATE .. AS SELECT` queries. [#24464](https://github.com/ClickHouse/ClickHouse/pull/24464) ([Anton Popov](https://github.com/CurtizJ)).
+* Support for `Parquet` format in `Kafka` tables. [#23412](https://github.com/ClickHouse/ClickHouse/pull/23412) ([Chao Ma](https://github.com/godliness)).
+
+#### Bug Fix
+
+* Use old modulo function version when used in partition key and primary key. Closes [#23508](https://github.com/ClickHouse/ClickHouse/issues/23508). [#24157](https://github.com/ClickHouse/ClickHouse/pull/24157) ([Kseniia Sumarokova](https://github.com/kssenii)). It was a source of backward incompatibility in previous releases.
+* Fixed the behavior when query `SYSTEM RESTART REPLICA` or `SYSTEM SYNC REPLICA` is being processed infinitely. This was detected on server with extremely little amount of RAM. [#24457](https://github.com/ClickHouse/ClickHouse/pull/24457) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix incorrect monotonicity of `toWeek` function. This fixes [#24422](https://github.com/ClickHouse/ClickHouse/issues/24422) . This bug was introduced in [#5212](https://github.com/ClickHouse/ClickHouse/pull/5212), and was exposed later by smarter partition pruner. [#24446](https://github.com/ClickHouse/ClickHouse/pull/24446) ([Amos Bird](https://github.com/amosbird)).
+* Fix drop partition with intersect fake parts. In rare cases there might be parts with mutation version greater than current block number. [#24321](https://github.com/ClickHouse/ClickHouse/pull/24321) ([Amos Bird](https://github.com/amosbird)).
+* Fixed a bug in moving Materialized View from Ordinary to Atomic database (`RENAME TABLE` query). Now inner table is moved to new database together with Materialized View. Fixes [#23926](https://github.com/ClickHouse/ClickHouse/issues/23926). [#24309](https://github.com/ClickHouse/ClickHouse/pull/24309) ([tavplubix](https://github.com/tavplubix)).
+* Allow empty HTTP headers in client requests. Fixes [#23901](https://github.com/ClickHouse/ClickHouse/issues/23901). [#24285](https://github.com/ClickHouse/ClickHouse/pull/24285) ([Ivan](https://github.com/abyss7)).
+* Set `max_threads = 1` to fix mutation fail of `Memory` tables. Closes [#24274](https://github.com/ClickHouse/ClickHouse/issues/24274). [#24275](https://github.com/ClickHouse/ClickHouse/pull/24275) ([flynn](https://github.com/ucasFL)).
+* Fix typo in implementation of `Memory` tables, this bug was introduced at [#15127](https://github.com/ClickHouse/ClickHouse/issues/15127). Closes [#24192](https://github.com/ClickHouse/ClickHouse/issues/24192). [#24193](https://github.com/ClickHouse/ClickHouse/pull/24193) ([张中南](https://github.com/plugine)).
+* Fix abnormal server termination due to `HDFS` becoming not accessible during query execution. Closes [#24117](https://github.com/ClickHouse/ClickHouse/issues/24117). [#24191](https://github.com/ClickHouse/ClickHouse/pull/24191) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix crash on updating of `Nested` column with const condition. [#24183](https://github.com/ClickHouse/ClickHouse/pull/24183) ([hexiaoting](https://github.com/hexiaoting)).
+* Fix race condition which could happen in RBAC under a heavy load. This PR fixes [#24090](https://github.com/ClickHouse/ClickHouse/issues/24090), [#24134](https://github.com/ClickHouse/ClickHouse/issues/24134),. [#24176](https://github.com/ClickHouse/ClickHouse/pull/24176) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix a rare bug that could lead to a partially initialized table that can serve write requests (insert/alter/so on). Now such tables will be in readonly mode. [#24122](https://github.com/ClickHouse/ClickHouse/pull/24122) ([alesapin](https://github.com/alesapin)).
+* Fix an issue: `EXPLAIN PIPELINE` with `SELECT xxx FINAL` showed a wrong pipeline. ([hexiaoting](https://github.com/hexiaoting)).
+* Fixed using const `DateTime` value vs `DateTime64` column in `WHERE`. [#24100](https://github.com/ClickHouse/ClickHouse/pull/24100) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fix crash in merge JOIN, closes [#24010](https://github.com/ClickHouse/ClickHouse/issues/24010). [#24013](https://github.com/ClickHouse/ClickHouse/pull/24013) ([vdimir](https://github.com/vdimir)).
+* Some `ALTER PARTITION` queries might cause `Part A intersects previous part B` and `Unexpected merged part C intersecting drop range D` errors in replication queue. It's fixed. Fixes [#23296](https://github.com/ClickHouse/ClickHouse/issues/23296). [#23997](https://github.com/ClickHouse/ClickHouse/pull/23997) ([tavplubix](https://github.com/tavplubix)).
+* Fix SIGSEGV for external GROUP BY and overflow row (i.e. queries like `SELECT FROM GROUP BY WITH TOTALS SETTINGS max_bytes_before_external_group_by>0, max_rows_to_group_by>0, group_by_overflow_mode='any', totals_mode='before_having'`). [#23962](https://github.com/ClickHouse/ClickHouse/pull/23962) ([Azat Khuzhin](https://github.com/azat)).
+* Fix keys metrics accounting for `CACHE` dictionary with duplicates in the source (leads to `DictCacheKeysRequestedMiss` overflows). [#23929](https://github.com/ClickHouse/ClickHouse/pull/23929) ([Azat Khuzhin](https://github.com/azat)).
+* Fix implementation of connection pool of `PostgreSQL` engine. Closes [#23897](https://github.com/ClickHouse/ClickHouse/issues/23897). [#23909](https://github.com/ClickHouse/ClickHouse/pull/23909) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix `distributed_group_by_no_merge = 2` with `GROUP BY` and aggregate function wrapped into regular function (had been broken in [#23546](https://github.com/ClickHouse/ClickHouse/issues/23546)). Throw exception in case of someone trying to use `distributed_group_by_no_merge = 2` with window functions. Disable `optimize_distributed_group_by_sharding_key` for queries with window functions. [#23906](https://github.com/ClickHouse/ClickHouse/pull/23906) ([Azat Khuzhin](https://github.com/azat)).
+* A fix for `s3` table function: better handling of HTTP errors. Response bodies of HTTP errors were being ignored earlier. [#23844](https://github.com/ClickHouse/ClickHouse/pull/23844) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* A fix for `s3` table function: better handling of URI's. Fixed an incompatibility with URLs containing `+` symbol, data with such keys could not be read previously. [#23822](https://github.com/ClickHouse/ClickHouse/pull/23822) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fix error `Can't initialize pipeline with empty pipe` for queries with `GLOBAL IN/JOIN` and `use_hedged_requests`. Fixes [#23431](https://github.com/ClickHouse/ClickHouse/issues/23431). [#23805](https://github.com/ClickHouse/ClickHouse/pull/23805) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix `CLEAR COLUMN` does not work when it is referenced by materialized view. Close [#23764](https://github.com/ClickHouse/ClickHouse/issues/23764). [#23781](https://github.com/ClickHouse/ClickHouse/pull/23781) ([flynn](https://github.com/ucasFL)).
+* Fix heap use after free when reading from HDFS if `Values` format is used. [#23761](https://github.com/ClickHouse/ClickHouse/pull/23761) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Avoid possible "Cannot schedule a task" error (in case some exception had been occurred) on INSERT into Distributed. [#23744](https://github.com/ClickHouse/ClickHouse/pull/23744) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed a bug in recovery of staled `ReplicatedMergeTree` replica. Some metadata updates could be ignored by staled replica if `ALTER` query was executed during downtime of the replica. [#23742](https://github.com/ClickHouse/ClickHouse/pull/23742) ([tavplubix](https://github.com/tavplubix)).
+* Fix a bug with `Join` and `WITH TOTALS`, close [#17718](https://github.com/ClickHouse/ClickHouse/issues/17718). [#23549](https://github.com/ClickHouse/ClickHouse/pull/23549) ([vdimir](https://github.com/vdimir)).
+* Fix possible `Block structure mismatch` error for queries with `UNION` which could possibly happen after filter-pushdown optimization. Fixes [#23029](https://github.com/ClickHouse/ClickHouse/issues/23029). [#23359](https://github.com/ClickHouse/ClickHouse/pull/23359) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Add type conversion when the setting `optimize_skip_unused_shards_rewrite_in` is enabled. This fixes MSan report. [#23219](https://github.com/ClickHouse/ClickHouse/pull/23219) ([Azat Khuzhin](https://github.com/azat)).
+* Add a missing check when updating nested subcolumns, close issue: [#22353](https://github.com/ClickHouse/ClickHouse/issues/22353). [#22503](https://github.com/ClickHouse/ClickHouse/pull/22503) ([hexiaoting](https://github.com/hexiaoting)).
+
+#### Build/Testing/Packaging Improvement
+
+* Support building on Illumos. [#24144](https://github.com/ClickHouse/ClickHouse/pull/24144). Adds support for building on Solaris-derived operating systems. [#23746](https://github.com/ClickHouse/ClickHouse/pull/23746) ([bnaecker](https://github.com/bnaecker)).
+* Add more benchmarks for hash tables, including the Swiss Table from Google (that appeared to be slower than ClickHouse hash map in our specific usage scenario). [#24111](https://github.com/ClickHouse/ClickHouse/pull/24111) ([Maksim Kita](https://github.com/kitaisreal)).
+* Update librdkafka 1.6.0-RC3 to 1.6.1. [#23874](https://github.com/ClickHouse/ClickHouse/pull/23874) ([filimonov](https://github.com/filimonov)).
+* Always enable `asynchronous-unwind-tables` explicitly. It may fix query profiler on AArch64. [#23602](https://github.com/ClickHouse/ClickHouse/pull/23602) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Avoid possible build dependency on locale and filesystem order. This allows reproducible builds. [#23600](https://github.com/ClickHouse/ClickHouse/pull/23600) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove a source of nondeterminism from build. Now builds at different point of time will produce byte-identical binaries. Partially addressed [#22113](https://github.com/ClickHouse/ClickHouse/issues/22113). [#23559](https://github.com/ClickHouse/ClickHouse/pull/23559) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add simple tool for benchmarking (Zoo)Keeper. [#23038](https://github.com/ClickHouse/ClickHouse/pull/23038) ([alesapin](https://github.com/alesapin)).
+
+
+## ClickHouse release 21.5, 2021-05-20
+
+#### Backward Incompatible Change
+
+* Change comparison of integers and floating point numbers when integer is not exactly representable in the floating point data type. In new version comparison will return false as the rounding error will occur. Example: `9223372036854775808.0 != 9223372036854775808`, because the number `9223372036854775808` is not representable as floating point number exactly (and `9223372036854775808.0` is rounded to `9223372036854776000.0`). But in previous version the comparison will return as the numbers are equal, because if the floating point number `9223372036854776000.0` get converted back to UInt64, it will yield `9223372036854775808`. For the reference, the Python programming language also treats these numbers as equal. But this behaviour was dependend on CPU model (different results on AMD64 and AArch64 for some out-of-range numbers), so we make the comparison more precise. It will treat int and float numbers equal only if int is represented in floating point type exactly. [#22595](https://github.com/ClickHouse/ClickHouse/pull/22595) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove support for `argMin` and `argMax` for single `Tuple` argument. The code was not memory-safe. The feature was added by mistake and it is confusing for people. These functions can be reintroduced under different names later. This fixes [#22384](https://github.com/ClickHouse/ClickHouse/issues/22384) and reverts [#17359](https://github.com/ClickHouse/ClickHouse/issues/17359). [#23393](https://github.com/ClickHouse/ClickHouse/pull/23393) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### New Feature
+
+* Added functions `dictGetChildren(dictionary, key)`, `dictGetDescendants(dictionary, key, level)`. Function `dictGetChildren` return all children as an array if indexes. It is a inverse transformation for `dictGetHierarchy`. Function `dictGetDescendants` return all descendants as if `dictGetChildren` was applied `level` times recursively. Zero `level` value is equivalent to infinity. Improved performance of `dictGetHierarchy`, `dictIsIn` functions. Closes [#14656](https://github.com/ClickHouse/ClickHouse/issues/14656). [#22096](https://github.com/ClickHouse/ClickHouse/pull/22096) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added function `dictGetOrNull`. It works like `dictGet`, but return `Null` in case key was not found in dictionary. Closes [#22375](https://github.com/ClickHouse/ClickHouse/issues/22375). [#22413](https://github.com/ClickHouse/ClickHouse/pull/22413) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added a table function `s3Cluster`, which allows to process files from `s3` in parallel on every node of a specified cluster. [#22012](https://github.com/ClickHouse/ClickHouse/pull/22012) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Added support for replicas and shards in MySQL/PostgreSQL table engine / table function. You can write `SELECT * FROM mysql('host{1,2}-{1|2}', ...)`. Closes [#20969](https://github.com/ClickHouse/ClickHouse/issues/20969). [#22217](https://github.com/ClickHouse/ClickHouse/pull/22217) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Added `ALTER TABLE ... FETCH PART ...` query. It's similar to `FETCH PARTITION`, but fetches only one part. [#22706](https://github.com/ClickHouse/ClickHouse/pull/22706) ([turbo jason](https://github.com/songenjie)).
+* Added a setting `max_distributed_depth` that limits the depth of recursive queries to `Distributed` tables. Closes [#20229](https://github.com/ClickHouse/ClickHouse/issues/20229). [#21942](https://github.com/ClickHouse/ClickHouse/pull/21942) ([flynn](https://github.com/ucasFL)).
+
+#### Performance Improvement
+
+* Improved performance of `intDiv` by dynamic dispatch for AVX2. This closes [#22314](https://github.com/ClickHouse/ClickHouse/issues/22314). [#23000](https://github.com/ClickHouse/ClickHouse/pull/23000) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improved performance of reading from `ArrowStream` input format for sources other then local file (e.g. URL). [#22673](https://github.com/ClickHouse/ClickHouse/pull/22673) ([nvartolomei](https://github.com/nvartolomei)).
+* Disabled compression by default when interacting with localhost (with clickhouse-client or server to server with distributed queries) via native protocol. It may improve performance of some import/export operations. This closes [#22234](https://github.com/ClickHouse/ClickHouse/issues/22234). [#22237](https://github.com/ClickHouse/ClickHouse/pull/22237) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Exclude values that does not belong to the shard from right part of IN section for distributed queries (under `optimize_skip_unused_shards_rewrite_in`, enabled by default, since it still requires `optimize_skip_unused_shards`). [#21511](https://github.com/ClickHouse/ClickHouse/pull/21511) ([Azat Khuzhin](https://github.com/azat)).
+* Improved performance of reading a subset of columns with File-like table engine and column-oriented format like Parquet, Arrow or ORC. This closes [#issue:20129](https://github.com/ClickHouse/ClickHouse/issues/20129). [#21302](https://github.com/ClickHouse/ClickHouse/pull/21302) ([keenwolf](https://github.com/keen-wolf)).
+* Allow to move more conditions to `PREWHERE` as it was before version 21.1 (adjustment of internal heuristics). Insufficient number of moved condtions could lead to worse performance. [#23397](https://github.com/ClickHouse/ClickHouse/pull/23397) ([Anton Popov](https://github.com/CurtizJ)).
+* Improved performance of ODBC connections and fixed all the outstanding issues from the backlog. Using `nanodbc` library instead of `Poco::ODBC`. Closes [#9678](https://github.com/ClickHouse/ClickHouse/issues/9678). Add support for DateTime64 and Decimal* for ODBC table engine. Closes [#21961](https://github.com/ClickHouse/ClickHouse/issues/21961). Fixed issue with cyrillic text being truncated. Closes [#16246](https://github.com/ClickHouse/ClickHouse/issues/16246). Added connection pools for odbc bridge. [#21972](https://github.com/ClickHouse/ClickHouse/pull/21972) ([Kseniia Sumarokova](https://github.com/kssenii)).
+
+#### Improvement
+
+* Increase `max_uri_size` (the maximum size of URL in HTTP interface) to 1 MiB by default. This closes [#21197](https://github.com/ClickHouse/ClickHouse/issues/21197). [#22997](https://github.com/ClickHouse/ClickHouse/pull/22997) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Set `background_fetches_pool_size` to `8` that is better for production usage with frequent small insertions or slow ZooKeeper cluster. [#22945](https://github.com/ClickHouse/ClickHouse/pull/22945) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* FlatDictionary added `initial_array_size`, `max_array_size` options. [#22521](https://github.com/ClickHouse/ClickHouse/pull/22521) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add new setting `non_replicated_deduplication_window` for non-replicated MergeTree inserts deduplication. [#22514](https://github.com/ClickHouse/ClickHouse/pull/22514) ([alesapin](https://github.com/alesapin)).
+* Update paths to the `CatBoost` model configs in config reloading. [#22434](https://github.com/ClickHouse/ClickHouse/pull/22434) ([Kruglov Pavel](https://github.com/Avogar)).
+* Added `Decimal256` type support in dictionaries. `Decimal256` is experimental feature. Closes [#20979](https://github.com/ClickHouse/ClickHouse/issues/20979). [#22960](https://github.com/ClickHouse/ClickHouse/pull/22960) ([Maksim Kita](https://github.com/kitaisreal)).
+* Enabled `async_socket_for_remote` by default (using less amount of OS threads for distributed queries). [#23683](https://github.com/ClickHouse/ClickHouse/pull/23683) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed `quantile(s)TDigest`. Added special handling of singleton centroids according to tdunning/t-digest 3.2+. Also a bug with over-compression of centroids in implementation of earlier version of the algorithm was fixed. [#23314](https://github.com/ClickHouse/ClickHouse/pull/23314) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Make function name `unhex` case insensitive for compatibility with MySQL. [#23229](https://github.com/ClickHouse/ClickHouse/pull/23229) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Implement functions `arrayHasAny`, `arrayHasAll`, `has`, `indexOf`, `countEqual` for generic case when types of array elements are different. In previous versions the functions `arrayHasAny`, `arrayHasAll` returned false and `has`, `indexOf`, `countEqual` thrown exception. Also add support for `Decimal` and big integer types in functions `has` and similar. This closes [#20272](https://github.com/ClickHouse/ClickHouse/issues/20272). [#23044](https://github.com/ClickHouse/ClickHouse/pull/23044) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Raised the threshold on max number of matches in result of the function `extractAllGroupsHorizontal`. [#23036](https://github.com/ClickHouse/ClickHouse/pull/23036) ([Vasily Nemkov](https://github.com/Enmk)).
+* Do not perform `optimize_skip_unused_shards` for cluster with one node. [#22999](https://github.com/ClickHouse/ClickHouse/pull/22999) ([Azat Khuzhin](https://github.com/azat)).
+* Added ability to run clickhouse-keeper (experimental drop-in replacement to ZooKeeper) with SSL. Config settings `keeper_server.tcp_port_secure` can be used for secure interaction between client and keeper-server. `keeper_server.raft_configuration.secure` can be used to enable internal secure communication between nodes. [#22992](https://github.com/ClickHouse/ClickHouse/pull/22992) ([alesapin](https://github.com/alesapin)).
+* Added ability to flush buffer only in background for `Buffer` tables. [#22986](https://github.com/ClickHouse/ClickHouse/pull/22986) ([Azat Khuzhin](https://github.com/azat)).
+* When selecting from MergeTree table with NULL in WHERE condition, in rare cases, exception was thrown. This closes [#20019](https://github.com/ClickHouse/ClickHouse/issues/20019). [#22978](https://github.com/ClickHouse/ClickHouse/pull/22978) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix error handling in Poco HTTP Client for AWS. [#22973](https://github.com/ClickHouse/ClickHouse/pull/22973) ([kreuzerkrieg](https://github.com/kreuzerkrieg)).
+* Respect `max_part_removal_threads` for `ReplicatedMergeTree`. [#22971](https://github.com/ClickHouse/ClickHouse/pull/22971) ([Azat Khuzhin](https://github.com/azat)).
+* Fix obscure corner case of MergeTree settings inactive_parts_to_throw_insert = 0 with inactive_parts_to_delay_insert > 0. [#22947](https://github.com/ClickHouse/ClickHouse/pull/22947) ([Azat Khuzhin](https://github.com/azat)).
+* `dateDiff` now works with `DateTime64` arguments (even for values outside of `DateTime` range) [#22931](https://github.com/ClickHouse/ClickHouse/pull/22931) ([Vasily Nemkov](https://github.com/Enmk)).
+* MaterializeMySQL (experimental feature): added an ability to replicate MySQL databases containing views without failing. This is accomplished by ignoring the views. [#22760](https://github.com/ClickHouse/ClickHouse/pull/22760) ([Christian](https://github.com/cfroystad)).
+* Allow RBAC row policy via postgresql protocol. Closes [#22658](https://github.com/ClickHouse/ClickHouse/issues/22658). PostgreSQL protocol is enabled in configuration by default. [#22755](https://github.com/ClickHouse/ClickHouse/pull/22755) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Add metric to track how much time is spend during waiting for Buffer layer lock. [#22725](https://github.com/ClickHouse/ClickHouse/pull/22725) ([Azat Khuzhin](https://github.com/azat)).
+* Allow to use CTE in VIEW definition. This closes [#22491](https://github.com/ClickHouse/ClickHouse/issues/22491). [#22657](https://github.com/ClickHouse/ClickHouse/pull/22657) ([Amos Bird](https://github.com/amosbird)).
+* Clear the rest of the screen and show cursor in `clickhouse-client` if previous program has left garbage in terminal. This closes [#16518](https://github.com/ClickHouse/ClickHouse/issues/16518). [#22634](https://github.com/ClickHouse/ClickHouse/pull/22634) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make `round` function to behave consistently on non-x86_64 platforms. Rounding half to nearest even (Banker's rounding) is used. [#22582](https://github.com/ClickHouse/ClickHouse/pull/22582) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Correctly check structure of blocks of data that are sending by Distributed tables. [#22325](https://github.com/ClickHouse/ClickHouse/pull/22325) ([Azat Khuzhin](https://github.com/azat)).
+* Allow publishing Kafka errors to a virtual column of Kafka engine, controlled by the `kafka_handle_error_mode` setting. [#21850](https://github.com/ClickHouse/ClickHouse/pull/21850) ([fastio](https://github.com/fastio)).
+* Add aliases `simpleJSONExtract/simpleJSONHas` to `visitParam/visitParamExtract{UInt, Int, Bool, Float, Raw, String}`. Fixes [#21383](https://github.com/ClickHouse/ClickHouse/issues/21383). [#21519](https://github.com/ClickHouse/ClickHouse/pull/21519) ([fastio](https://github.com/fastio)).
+* Add `clickhouse-library-bridge` for library dictionary source. Closes [#9502](https://github.com/ClickHouse/ClickHouse/issues/9502). [#21509](https://github.com/ClickHouse/ClickHouse/pull/21509) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Forbid to drop a column if it's referenced by materialized view. Closes [#21164](https://github.com/ClickHouse/ClickHouse/issues/21164). [#21303](https://github.com/ClickHouse/ClickHouse/pull/21303) ([flynn](https://github.com/ucasFL)).
+* Support dynamic interserver credentials (rotating credentials without downtime). [#14113](https://github.com/ClickHouse/ClickHouse/pull/14113) ([johnskopis](https://github.com/johnskopis)).
+* Add support for Kafka storage with `Arrow` and `ArrowStream` format messages. [#23415](https://github.com/ClickHouse/ClickHouse/pull/23415) ([Chao Ma](https://github.com/godliness)).
+* Fixed missing semicolon in exception message. The user may find this exception message unpleasant to read. [#23208](https://github.com/ClickHouse/ClickHouse/pull/23208) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed missing whitespace in some exception messages about `LowCardinality` type. [#23207](https://github.com/ClickHouse/ClickHouse/pull/23207) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Some values were formatted with alignment in center in table cells in `Markdown` format. Not anymore. [#23096](https://github.com/ClickHouse/ClickHouse/pull/23096) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove non-essential details from suggestions in clickhouse-client. This closes [#22158](https://github.com/ClickHouse/ClickHouse/issues/22158). [#23040](https://github.com/ClickHouse/ClickHouse/pull/23040) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Correct calculation of `bytes_allocated` field in system.dictionaries for sparse_hashed dictionaries. [#22867](https://github.com/ClickHouse/ClickHouse/pull/22867) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed approximate total rows accounting for reverse reading from MergeTree. [#22726](https://github.com/ClickHouse/ClickHouse/pull/22726) ([Azat Khuzhin](https://github.com/azat)).
+* Fix the case when it was possible to configure dictionary with clickhouse source that was looking to itself that leads to infinite loop. Closes [#14314](https://github.com/ClickHouse/ClickHouse/issues/14314). [#22479](https://github.com/ClickHouse/ClickHouse/pull/22479) ([Maksim Kita](https://github.com/kitaisreal)).
+
+#### Bug Fix
+
+* Multiple fixes for hedged requests. Fixed an error `Can't initialize pipeline with empty pipe` for queries with `GLOBAL IN/JOIN` when the setting `use_hedged_requests` is enabled. Fixes [#23431](https://github.com/ClickHouse/ClickHouse/issues/23431). [#23805](https://github.com/ClickHouse/ClickHouse/pull/23805) ([Nikolai Kochetov](https://github.com/KochetovNicolai)). Fixed a race condition in hedged connections which leads to crash. This fixes [#22161](https://github.com/ClickHouse/ClickHouse/issues/22161). [#22443](https://github.com/ClickHouse/ClickHouse/pull/22443) ([Kruglov Pavel](https://github.com/Avogar)). Fix possible crash in case if `unknown packet` was received from remote query (with `async_socket_for_remote` enabled). Fixes [#21167](https://github.com/ClickHouse/ClickHouse/issues/21167). [#23309](https://github.com/ClickHouse/ClickHouse/pull/23309) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed the behavior when disabling `input_format_with_names_use_header ` setting discards all the input with CSVWithNames format. This fixes [#22406](https://github.com/ClickHouse/ClickHouse/issues/22406). [#23202](https://github.com/ClickHouse/ClickHouse/pull/23202) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed remote JDBC bridge timeout connection issue. Closes [#9609](https://github.com/ClickHouse/ClickHouse/issues/9609). [#23771](https://github.com/ClickHouse/ClickHouse/pull/23771) ([Maksim Kita](https://github.com/kitaisreal), [alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix the logic of initial load of `complex_key_hashed` if `update_field` is specified. Closes [#23800](https://github.com/ClickHouse/ClickHouse/issues/23800). [#23824](https://github.com/ClickHouse/ClickHouse/pull/23824) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fixed crash when `PREWHERE` and row policy filter are both in effect with empty result. [#23763](https://github.com/ClickHouse/ClickHouse/pull/23763) ([Amos Bird](https://github.com/amosbird)).
+* Avoid possible "Cannot schedule a task" error (in case some exception had been occurred) on INSERT into Distributed. [#23744](https://github.com/ClickHouse/ClickHouse/pull/23744) ([Azat Khuzhin](https://github.com/azat)).
+* Added an exception in case of completely the same values in both samples in aggregate function `mannWhitneyUTest`. This fixes [#23646](https://github.com/ClickHouse/ClickHouse/issues/23646). [#23654](https://github.com/ClickHouse/ClickHouse/pull/23654) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed server fault when inserting data through HTTP caused an exception. This fixes [#23512](https://github.com/ClickHouse/ClickHouse/issues/23512). [#23643](https://github.com/ClickHouse/ClickHouse/pull/23643) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fixed misinterpretation of some `LIKE` expressions with escape sequences. [#23610](https://github.com/ClickHouse/ClickHouse/pull/23610) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed restart / stop command hanging. Closes [#20214](https://github.com/ClickHouse/ClickHouse/issues/20214). [#23552](https://github.com/ClickHouse/ClickHouse/pull/23552) ([filimonov](https://github.com/filimonov)).
+* Fixed `COLUMNS` matcher in case of multiple JOINs in select query. Closes [#22736](https://github.com/ClickHouse/ClickHouse/issues/22736). [#23501](https://github.com/ClickHouse/ClickHouse/pull/23501) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fixed a crash when modifying column's default value when a column itself is used as `ReplacingMergeTree`'s parameter. [#23483](https://github.com/ClickHouse/ClickHouse/pull/23483) ([hexiaoting](https://github.com/hexiaoting)).
+* Fixed corner cases in vertical merges with `ReplacingMergeTree`. In rare cases they could lead to fails of merges with exceptions like `Incomplete granules are not allowed while blocks are granules size`. [#23459](https://github.com/ClickHouse/ClickHouse/pull/23459) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed bug that does not allow cast from empty array literal, to array with dimensions greater than 1, e.g. `CAST([] AS Array(Array(String)))`. Closes [#14476](https://github.com/ClickHouse/ClickHouse/issues/14476). [#23456](https://github.com/ClickHouse/ClickHouse/pull/23456) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fixed a bug when `deltaSum` aggregate function produced incorrect result after resetting the counter. [#23437](https://github.com/ClickHouse/ClickHouse/pull/23437) ([Russ Frank](https://github.com/rf)).
+* Fixed `Cannot unlink file` error on unsuccessful creation of ReplicatedMergeTree table with multidisk configuration. This closes [#21755](https://github.com/ClickHouse/ClickHouse/issues/21755). [#23433](https://github.com/ClickHouse/ClickHouse/pull/23433) ([tavplubix](https://github.com/tavplubix)).
+* Fixed incompatible constant expression generation during partition pruning based on virtual columns. This fixes https://github.com/ClickHouse/ClickHouse/pull/21401#discussion_r611888913. [#23366](https://github.com/ClickHouse/ClickHouse/pull/23366) ([Amos Bird](https://github.com/amosbird)).
+* Fixed a crash when setting join_algorithm is set to 'auto' and Join is performed with a Dictionary. Close [#23002](https://github.com/ClickHouse/ClickHouse/issues/23002). [#23312](https://github.com/ClickHouse/ClickHouse/pull/23312) ([Vladimir](https://github.com/vdimir)).
+* Don't relax NOT conditions during partition pruning. This fixes [#23305](https://github.com/ClickHouse/ClickHouse/issues/23305) and [#21539](https://github.com/ClickHouse/ClickHouse/issues/21539). [#23310](https://github.com/ClickHouse/ClickHouse/pull/23310) ([Amos Bird](https://github.com/amosbird)).
+* Fixed very rare race condition on background cleanup of old blocks. It might cause a block not to be deduplicated if it's too close to the end of deduplication window. [#23301](https://github.com/ClickHouse/ClickHouse/pull/23301) ([tavplubix](https://github.com/tavplubix)).
+* Fixed very rare (distributed) race condition between creation and removal of ReplicatedMergeTree tables. It might cause exceptions like `node doesn't exist` on attempt to create replicated table. Fixes [#21419](https://github.com/ClickHouse/ClickHouse/issues/21419). [#23294](https://github.com/ClickHouse/ClickHouse/pull/23294) ([tavplubix](https://github.com/tavplubix)).
+* Fixed simple key dictionary from DDL creation if primary key is not first attribute. Fixes [#23236](https://github.com/ClickHouse/ClickHouse/issues/23236). [#23262](https://github.com/ClickHouse/ClickHouse/pull/23262) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fixed reading from ODBC when there are many long column names in a table. Closes [#8853](https://github.com/ClickHouse/ClickHouse/issues/8853). [#23215](https://github.com/ClickHouse/ClickHouse/pull/23215) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* MaterializeMySQL (experimental feature): fixed `Not found column` error when selecting from `MaterializeMySQL` with condition on key column. Fixes [#22432](https://github.com/ClickHouse/ClickHouse/issues/22432). [#23200](https://github.com/ClickHouse/ClickHouse/pull/23200) ([tavplubix](https://github.com/tavplubix)).
+* Correct aliases handling if subquery was optimized to constant. Fixes [#22924](https://github.com/ClickHouse/ClickHouse/issues/22924). Fixes [#10401](https://github.com/ClickHouse/ClickHouse/issues/10401). [#23191](https://github.com/ClickHouse/ClickHouse/pull/23191) ([Maksim Kita](https://github.com/kitaisreal)).
+* Server might fail to start if `data_type_default_nullable` setting is enabled in default profile, it's fixed. Fixes [#22573](https://github.com/ClickHouse/ClickHouse/issues/22573). [#23185](https://github.com/ClickHouse/ClickHouse/pull/23185) ([tavplubix](https://github.com/tavplubix)).
+* Fixed a crash on shutdown which happened because of wrong accounting of current connections. [#23154](https://github.com/ClickHouse/ClickHouse/pull/23154) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed `Table .inner_id... doesn't exist` error when selecting from Materialized View after detaching it from Atomic database and attaching back. [#23047](https://github.com/ClickHouse/ClickHouse/pull/23047) ([tavplubix](https://github.com/tavplubix)).
+* Fix error `Cannot find column in ActionsDAG result` which may happen if subquery uses `untuple`. Fixes [#22290](https://github.com/ClickHouse/ClickHouse/issues/22290). [#22991](https://github.com/ClickHouse/ClickHouse/pull/22991) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix usage of constant columns of type `Map` with nullable values. [#22939](https://github.com/ClickHouse/ClickHouse/pull/22939) ([Anton Popov](https://github.com/CurtizJ)).
+* fixed `formatDateTime()` on `DateTime64` and "%C" format specifier fixed `toDateTime64()` for large values and non-zero scale. [#22937](https://github.com/ClickHouse/ClickHouse/pull/22937) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fixed a crash when using `mannWhitneyUTest` and `rankCorr` with window functions. This fixes [#22728](https://github.com/ClickHouse/ClickHouse/issues/22728). [#22876](https://github.com/ClickHouse/ClickHouse/pull/22876) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* LIVE VIEW (experimental feature): fixed possible hanging in concurrent DROP/CREATE of TEMPORARY LIVE VIEW in `TemporaryLiveViewCleaner`, [see](https://gist.github.com/vzakaznikov/0c03195960fc86b56bfe2bc73a90019e). [#22858](https://github.com/ClickHouse/ClickHouse/pull/22858) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed pushdown of `HAVING` in case, when filter column is used in aggregation. [#22763](https://github.com/ClickHouse/ClickHouse/pull/22763) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed possible hangs in Zookeeper requests in case of OOM exception. Fixes [#22438](https://github.com/ClickHouse/ClickHouse/issues/22438). [#22684](https://github.com/ClickHouse/ClickHouse/pull/22684) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed wait for mutations on several replicas for ReplicatedMergeTree table engines. Previously, mutation/alter query may finish before mutation actually executed on other replicas. [#22669](https://github.com/ClickHouse/ClickHouse/pull/22669) ([alesapin](https://github.com/alesapin)).
+* Fixed exception for Log with nested types without columns in the SELECT clause. [#22654](https://github.com/ClickHouse/ClickHouse/pull/22654) ([Azat Khuzhin](https://github.com/azat)).
+* Fix unlimited wait for auxiliary AWS requests. [#22594](https://github.com/ClickHouse/ClickHouse/pull/22594) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fixed a crash when client closes connection very early [#22579](https://github.com/ClickHouse/ClickHouse/issues/22579). [#22591](https://github.com/ClickHouse/ClickHouse/pull/22591) ([nvartolomei](https://github.com/nvartolomei)).
+* `Map` data type (experimental feature): fixed an incorrect formatting of function `map` in distributed queries. [#22588](https://github.com/ClickHouse/ClickHouse/pull/22588) ([foolchi](https://github.com/foolchi)).
+* Fixed deserialization of empty string without newline at end of TSV format. This closes [#20244](https://github.com/ClickHouse/ClickHouse/issues/20244). Possible workaround without version update: set `input_format_null_as_default` to zero. It was zero in old versions. [#22527](https://github.com/ClickHouse/ClickHouse/pull/22527) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed wrong cast of a column of `LowCardinality` type in Merge Join algorithm. Close [#22386](https://github.com/ClickHouse/ClickHouse/issues/22386), close [#22388](https://github.com/ClickHouse/ClickHouse/issues/22388). [#22510](https://github.com/ClickHouse/ClickHouse/pull/22510) ([Vladimir](https://github.com/vdimir)).
+* Buffer overflow (on read) was possible in `tokenbf_v1` full text index. The excessive bytes are not used but the read operation may lead to crash in rare cases. This closes [#19233](https://github.com/ClickHouse/ClickHouse/issues/19233). [#22421](https://github.com/ClickHouse/ClickHouse/pull/22421) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Do not limit HTTP chunk size. Fixes [#21907](https://github.com/ClickHouse/ClickHouse/issues/21907). [#22322](https://github.com/ClickHouse/ClickHouse/pull/22322) ([Ivan](https://github.com/abyss7)).
+* Fixed a bug, which leads to underaggregation of data in case of enabled `optimize_aggregation_in_order` and many parts in table. Slightly improve performance of aggregation with enabled `optimize_aggregation_in_order`. [#21889](https://github.com/ClickHouse/ClickHouse/pull/21889) ([Anton Popov](https://github.com/CurtizJ)).
+* Check if table function view is used as a column. This complements #20350. [#21465](https://github.com/ClickHouse/ClickHouse/pull/21465) ([Amos Bird](https://github.com/amosbird)).
+* Fix "unknown column" error for tables with `Merge` engine in queris with `JOIN` and aggregation. Closes [#18368](https://github.com/ClickHouse/ClickHouse/issues/18368), close [#22226](https://github.com/ClickHouse/ClickHouse/issues/22226). [#21370](https://github.com/ClickHouse/ClickHouse/pull/21370) ([Vladimir](https://github.com/vdimir)).
+* Fixed name clashes in pushdown optimization. It caused incorrect `WHERE` filtration after FULL JOIN. Close [#20497](https://github.com/ClickHouse/ClickHouse/issues/20497). [#20622](https://github.com/ClickHouse/ClickHouse/pull/20622) ([Vladimir](https://github.com/vdimir)).
+* Fixed very rare bug when quorum insert with `quorum_parallel=1` is not really "quorum" because of deduplication. [#18215](https://github.com/ClickHouse/ClickHouse/pull/18215) ([filimonov](https://github.com/filimonov) - reported, [alesapin](https://github.com/alesapin) - fixed).
+
+#### Build/Testing/Packaging Improvement
+
+* Run stateless tests in parallel in CI. [#22300](https://github.com/ClickHouse/ClickHouse/pull/22300) ([alesapin](https://github.com/alesapin)).
+* Simplify debian packages. This fixes [#21698](https://github.com/ClickHouse/ClickHouse/issues/21698). [#22976](https://github.com/ClickHouse/ClickHouse/pull/22976) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added support for ClickHouse build on Apple M1. [#21639](https://github.com/ClickHouse/ClickHouse/pull/21639) ([changvvb](https://github.com/changvvb)).
+* Fixed ClickHouse Keeper build for MacOS. [#22860](https://github.com/ClickHouse/ClickHouse/pull/22860) ([alesapin](https://github.com/alesapin)).
+* Fixed some tests on AArch64 platform. [#22596](https://github.com/ClickHouse/ClickHouse/pull/22596) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Added function alignment for possibly better performance. [#21431](https://github.com/ClickHouse/ClickHouse/pull/21431) ([Danila Kutenin](https://github.com/danlark1)).
+* Adjust some tests to output identical results on amd64 and aarch64 (qemu). The result was depending on implementation specific CPU behaviour. [#22590](https://github.com/ClickHouse/ClickHouse/pull/22590) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow query profiling only on x86_64. See [#15174](https://github.com/ClickHouse/ClickHouse/issues/15174#issuecomment-812954965) and [#15638](https://github.com/ClickHouse/ClickHouse/issues/15638#issuecomment-703805337). This closes [#15638](https://github.com/ClickHouse/ClickHouse/issues/15638). [#22580](https://github.com/ClickHouse/ClickHouse/pull/22580) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow building with unbundled xz (lzma) using `USE_INTERNAL_XZ_LIBRARY=OFF` CMake option. [#22571](https://github.com/ClickHouse/ClickHouse/pull/22571) ([Kfir Itzhak](https://github.com/mastertheknife)).
+* Enable bundled `openldap` on `ppc64le` [#22487](https://github.com/ClickHouse/ClickHouse/pull/22487) ([Kfir Itzhak](https://github.com/mastertheknife)).
+* Disable incompatible libraries (platform specific typically) on `ppc64le` [#22475](https://github.com/ClickHouse/ClickHouse/pull/22475) ([Kfir Itzhak](https://github.com/mastertheknife)).
+* Add Jepsen test in CI for clickhouse Keeper. [#22373](https://github.com/ClickHouse/ClickHouse/pull/22373) ([alesapin](https://github.com/alesapin)).
+* Build `jemalloc` with support for [heap profiling](https://github.com/jemalloc/jemalloc/wiki/Use-Case%3A-Heap-Profiling). [#22834](https://github.com/ClickHouse/ClickHouse/pull/22834) ([nvartolomei](https://github.com/nvartolomei)).
+* Avoid UB in `*Log` engines for rwlock unlock due to unlock from another thread. [#22583](https://github.com/ClickHouse/ClickHouse/pull/22583) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed UB by unlocking the rwlock of the TinyLog from the same thread. [#22560](https://github.com/ClickHouse/ClickHouse/pull/22560) ([Azat Khuzhin](https://github.com/azat)).
+
+
+## ClickHouse release 21.4
+
+### ClickHouse release 21.4.1 2021-04-12
+
+#### Backward Incompatible Change
+
+* The `toStartOfIntervalFunction` will align hour intervals to the midnight (in previous versions they were aligned to the start of unix epoch). For example, `toStartOfInterval(x, INTERVAL 11 HOUR)` will split every day into three intervals: `00:00:00..10:59:59`, `11:00:00..21:59:59` and `22:00:00..23:59:59`. This behaviour is more suited for practical needs. This closes [#9510](https://github.com/ClickHouse/ClickHouse/issues/9510). [#22060](https://github.com/ClickHouse/ClickHouse/pull/22060) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* `Age` and `Precision` in graphite rollup configs should increase from retention to retention. Now it's checked and the wrong config raises an exception. [#21496](https://github.com/ClickHouse/ClickHouse/pull/21496) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
+* Fix `cutToFirstSignificantSubdomainCustom()`/`firstSignificantSubdomainCustom()` returning wrong result for 3+ level domains present in custom top-level domain list. For input domains matching these custom top-level domains, the third-level domain was considered to be the first significant one. This is now fixed. This change may introduce incompatibility if the function is used in e.g. the sharding key. [#21946](https://github.com/ClickHouse/ClickHouse/pull/21946) ([Azat Khuzhin](https://github.com/azat)).
+* Column `keys` in table `system.dictionaries` was replaced to columns `key.names` and `key.types`. Columns `key.names`, `key.types`, `attribute.names`, `attribute.types` from `system.dictionaries` table does not require dictionary to be loaded. [#21884](https://github.com/ClickHouse/ClickHouse/pull/21884) ([Maksim Kita](https://github.com/kitaisreal)).
+* Now replicas that are processing the `ALTER TABLE ATTACH PART[ITION]` command search in their `detached/` folders before fetching the data from other replicas. As an implementation detail, a new command `ATTACH_PART` is introduced in the replicated log. Parts are searched and compared by their checksums. [#18978](https://github.com/ClickHouse/ClickHouse/pull/18978) ([Mike Kot](https://github.com/myrrc)). **Note**:
+  * `ATTACH PART[ITION]` queries may not work during cluster upgrade.
+  * It's not possible to rollback to older ClickHouse version after executing `ALTER ... ATTACH` query in new version as the old servers would fail to pass the `ATTACH_PART` entry in the replicated log.
+* In this version, empty `<remote_url_allow_hosts></remote_url_allow_hosts>` will block all access to remote hosts while in previous versions it did nothing. If you want to keep old behaviour and you have empty `remote_url_allow_hosts` element in configuration file, remove it. [#20058](https://github.com/ClickHouse/ClickHouse/pull/20058) ([Vladimir Chebotarev](https://github.com/excitoon)).
+
+
+#### New Feature
+
+* Extended range of `DateTime64` to support dates from year 1925 to 2283. Improved support of `DateTime` around zero date (`1970-01-01`). [#9404](https://github.com/ClickHouse/ClickHouse/pull/9404) ([alexey-milovidov](https://github.com/alexey-milovidov), [Vasily Nemkov](https://github.com/Enmk)). Not every time and date functions are working for extended range of dates.
+* Added support of Kerberos authentication for preconfigured users and HTTP requests (GSS-SPNEGO). [#14995](https://github.com/ClickHouse/ClickHouse/pull/14995) ([Denis Glazachev](https://github.com/traceon)).
+* Add `prefer_column_name_to_alias` setting to use original column names instead of aliases. it is needed to be more compatible with common databases' aliasing rules. This is for [#9715](https://github.com/ClickHouse/ClickHouse/issues/9715) and [#9887](https://github.com/ClickHouse/ClickHouse/issues/9887). [#22044](https://github.com/ClickHouse/ClickHouse/pull/22044) ([Amos Bird](https://github.com/amosbird)).
+* Added functions `dictGetChildren(dictionary, key)`, `dictGetDescendants(dictionary, key, level)`. Function `dictGetChildren` return all children as an array if indexes. It is a inverse transformation for `dictGetHierarchy`. Function `dictGetDescendants` return all descendants as if `dictGetChildren` was applied `level` times recursively. Zero `level` value is equivalent to infinity. Closes [#14656](https://github.com/ClickHouse/ClickHouse/issues/14656). [#22096](https://github.com/ClickHouse/ClickHouse/pull/22096) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added `executable_pool` dictionary source. Close [#14528](https://github.com/ClickHouse/ClickHouse/issues/14528). [#21321](https://github.com/ClickHouse/ClickHouse/pull/21321) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added table function `dictionary`. It works the same way as `Dictionary` engine. Closes [#21560](https://github.com/ClickHouse/ClickHouse/issues/21560). [#21910](https://github.com/ClickHouse/ClickHouse/pull/21910) ([Maksim Kita](https://github.com/kitaisreal)).
+* Support `Nullable` type for `PolygonDictionary` attribute. [#21890](https://github.com/ClickHouse/ClickHouse/pull/21890) ([Maksim Kita](https://github.com/kitaisreal)).
+* Functions `dictGet`, `dictHas` use current database name if it is not specified for dictionaries created with DDL. Closes [#21632](https://github.com/ClickHouse/ClickHouse/issues/21632). [#21859](https://github.com/ClickHouse/ClickHouse/pull/21859) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added function `dictGetOrNull`. It works like `dictGet`, but return `Null` in case key was not found in dictionary. Closes [#22375](https://github.com/ClickHouse/ClickHouse/issues/22375). [#22413](https://github.com/ClickHouse/ClickHouse/pull/22413) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added async update in `ComplexKeyCache`, `SSDCache`, `SSDComplexKeyCache` dictionaries. Added support for `Nullable` type in `Cache`, `ComplexKeyCache`, `SSDCache`, `SSDComplexKeyCache` dictionaries. Added support for multiple attributes fetch with `dictGet`, `dictGetOrDefault` functions. Fixes [#21517](https://github.com/ClickHouse/ClickHouse/issues/21517). [#20595](https://github.com/ClickHouse/ClickHouse/pull/20595) ([Maksim Kita](https://github.com/kitaisreal)).
+* Support `dictHas` function for `RangeHashedDictionary`. Fixes [#6680](https://github.com/ClickHouse/ClickHouse/issues/6680). [#19816](https://github.com/ClickHouse/ClickHouse/pull/19816) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add function `timezoneOf` that returns the timezone name of `DateTime` or `DateTime64` data types. This does not close [#9959](https://github.com/ClickHouse/ClickHouse/issues/9959). Fix inconsistencies in function names: add aliases `timezone` and `timeZone` as well as `toTimezone` and `toTimeZone` and `timezoneOf` and `timeZoneOf`. [#22001](https://github.com/ClickHouse/ClickHouse/pull/22001) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add new optional clause `GRANTEES` for `CREATE/ALTER USER` commands. It specifies users or roles which are allowed to receive grants from this user on condition this user has also all required access granted with grant option. By default `GRANTEES ANY` is used which means a user with grant option can grant to anyone. Syntax: `CREATE USER ... GRANTEES {user | role | ANY | NONE} [,...] [EXCEPT {user | role} [,...]]`. [#21641](https://github.com/ClickHouse/ClickHouse/pull/21641) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Add new column `slowdowns_count` to `system.clusters`. When using hedged requests, it shows how many times we switched to another replica because this replica was responding slowly. Also show actual value of `errors_count` in `system.clusters`. [#21480](https://github.com/ClickHouse/ClickHouse/pull/21480) ([Kruglov Pavel](https://github.com/Avogar)).
+* Add `_partition_id` virtual column for `MergeTree*` engines. Allow to prune partitions by `_partition_id`. Add `partitionID()` function to calculate partition id string. [#21401](https://github.com/ClickHouse/ClickHouse/pull/21401) ([Amos Bird](https://github.com/amosbird)).
+* Add function `isIPAddressInRange` to test if an IPv4 or IPv6 address is contained in a given CIDR network prefix. [#21329](https://github.com/ClickHouse/ClickHouse/pull/21329) ([PHO](https://github.com/depressed-pho)).
+* Added new SQL command `ALTER TABLE 'table_name' UNFREEZE [PARTITION 'part_expr'] WITH NAME 'backup_name'`. This command is needed to properly remove 'freezed' partitions from all disks. [#21142](https://github.com/ClickHouse/ClickHouse/pull/21142) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Supports implicit key type conversion for JOIN. [#19885](https://github.com/ClickHouse/ClickHouse/pull/19885) ([Vladimir](https://github.com/vdimir)).
+
+#### Experimental Feature
+
+* Support `RANGE OFFSET` frame (for window functions) for floating point types. Implement `lagInFrame`/`leadInFrame` window functions, which are analogous to `lag`/`lead`, but respect the window frame. They are identical when the frame is `between unbounded preceding and unbounded following`. This closes [#5485](https://github.com/ClickHouse/ClickHouse/issues/5485). [#21895](https://github.com/ClickHouse/ClickHouse/pull/21895) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Zero-copy replication for `ReplicatedMergeTree` over S3 storage. [#16240](https://github.com/ClickHouse/ClickHouse/pull/16240) ([ianton-ru](https://github.com/ianton-ru)).
+* Added possibility to migrate existing S3 disk to the schema with backup-restore capabilities. [#22070](https://github.com/ClickHouse/ClickHouse/pull/22070) ([Pavel Kovalenko](https://github.com/Jokser)).
+
+#### Performance Improvement
+
+* Supported parallel formatting in `clickhouse-local` and everywhere else. [#21630](https://github.com/ClickHouse/ClickHouse/pull/21630) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Support parallel parsing for `CSVWithNames` and `TSVWithNames` formats. This closes [#21085](https://github.com/ClickHouse/ClickHouse/issues/21085). [#21149](https://github.com/ClickHouse/ClickHouse/pull/21149) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Enable read with mmap IO for file ranges from 64 MiB (the settings `min_bytes_to_use_mmap_io`). It may lead to moderate performance improvement. [#22326](https://github.com/ClickHouse/ClickHouse/pull/22326) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add cache for files read with `min_bytes_to_use_mmap_io` setting. It makes significant (2x and more) performance improvement when the value of the setting is small by avoiding frequent mmap/munmap calls and the consequent page faults. Note that mmap IO has major drawbacks that makes it less reliable in production (e.g. hung or SIGBUS on faulty disks; less controllable memory usage). Nevertheless it is good in benchmarks. [#22206](https://github.com/ClickHouse/ClickHouse/pull/22206) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Avoid unnecessary data copy when using codec `NONE`. Please note that codec `NONE` is mostly useless - it's recommended to always use compression (`LZ4` is by default). Despite the common belief, disabling compression may not improve performance (the opposite effect is possible). The `NONE` codec is useful in some cases: - when data is uncompressable; - for synthetic benchmarks. [#22145](https://github.com/ClickHouse/ClickHouse/pull/22145) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Faster `GROUP BY` with small `max_rows_to_group_by` and `group_by_overflow_mode='any'`. [#21856](https://github.com/ClickHouse/ClickHouse/pull/21856) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Optimize performance of queries like `SELECT ... FINAL ... WHERE`. Now in queries with `FINAL` it's allowed to move to `PREWHERE` columns, which are in sorting key. [#21830](https://github.com/ClickHouse/ClickHouse/pull/21830) ([foolchi](https://github.com/foolchi)).
+* Improved performance by replacing `memcpy` to another implementation. This closes [#18583](https://github.com/ClickHouse/ClickHouse/issues/18583). [#21520](https://github.com/ClickHouse/ClickHouse/pull/21520) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve performance of aggregation in order of sorting key (with enabled setting `optimize_aggregation_in_order`). [#19401](https://github.com/ClickHouse/ClickHouse/pull/19401) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Improvement
+
+* Add connection pool for PostgreSQL table/database engine and dictionary source. Should fix [#21444](https://github.com/ClickHouse/ClickHouse/issues/21444). [#21839](https://github.com/ClickHouse/ClickHouse/pull/21839) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Support non-default table schema for postgres storage/table-function. Closes [#21701](https://github.com/ClickHouse/ClickHouse/issues/21701). [#21711](https://github.com/ClickHouse/ClickHouse/pull/21711) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Support replicas priority for postgres dictionary source. [#21710](https://github.com/ClickHouse/ClickHouse/pull/21710) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Introduce a new merge tree setting `min_bytes_to_rebalance_partition_over_jbod` which allows assigning new parts to different disks of a JBOD volume in a balanced way. [#16481](https://github.com/ClickHouse/ClickHouse/pull/16481) ([Amos Bird](https://github.com/amosbird)).
+* Added `Grant`, `Revoke` and `System` values of `query_kind` column for corresponding queries in `system.query_log`. [#21102](https://github.com/ClickHouse/ClickHouse/pull/21102) ([Vasily Nemkov](https://github.com/Enmk)).
+* Allow customizing timeouts for HTTP connections used for replication independently from other HTTP timeouts. [#20088](https://github.com/ClickHouse/ClickHouse/pull/20088) ([nvartolomei](https://github.com/nvartolomei)).
+* Better exception message in client in case of exception while server is writing blocks. In previous versions client may get misleading message like `Data compressed with different methods`. [#22427](https://github.com/ClickHouse/ClickHouse/pull/22427) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix error `Directory tmp_fetch_XXX already exists` which could happen after failed fetch part. Delete temporary fetch directory if it already exists. Fixes [#14197](https://github.com/ClickHouse/ClickHouse/issues/14197). [#22411](https://github.com/ClickHouse/ClickHouse/pull/22411) ([nvartolomei](https://github.com/nvartolomei)).
+* Fix MSan report for function `range` with `UInt256` argument (support for large integers is experimental). This closes [#22157](https://github.com/ClickHouse/ClickHouse/issues/22157). [#22387](https://github.com/ClickHouse/ClickHouse/pull/22387) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add `current_database` column to `system.processes` table. It contains the current database of the query. [#22365](https://github.com/ClickHouse/ClickHouse/pull/22365) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Add case-insensitive history search/navigation and subword movement features to `clickhouse-client`. [#22105](https://github.com/ClickHouse/ClickHouse/pull/22105) ([Amos Bird](https://github.com/amosbird)).
+* If tuple of NULLs, e.g. `(NULL, NULL)` is on the left hand side of `IN` operator with tuples of non-NULLs on the right hand side, e.g. `SELECT (NULL, NULL) IN ((0, 0), (3, 1))` return 0 instead of throwing an exception about incompatible types. The expression may also appear due to optimization of something like `SELECT (NULL, NULL) = (8, 0) OR (NULL, NULL) = (3, 2) OR (NULL, NULL) = (0, 0) OR (NULL, NULL) = (3, 1)`. This closes [#22017](https://github.com/ClickHouse/ClickHouse/issues/22017). [#22063](https://github.com/ClickHouse/ClickHouse/pull/22063) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Update used version of simdjson to 0.9.1. This fixes [#21984](https://github.com/ClickHouse/ClickHouse/issues/21984). [#22057](https://github.com/ClickHouse/ClickHouse/pull/22057) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Added case insensitive aliases for `CONNECTION_ID()` and `VERSION()` functions. This fixes [#22028](https://github.com/ClickHouse/ClickHouse/issues/22028). [#22042](https://github.com/ClickHouse/ClickHouse/pull/22042) ([Eugene Klimov](https://github.com/Slach)).
+* Add option `strict_increase` to `windowFunnel` function to calculate each event once (resolve [#21835](https://github.com/ClickHouse/ClickHouse/issues/21835)). [#22025](https://github.com/ClickHouse/ClickHouse/pull/22025) ([Vladimir](https://github.com/vdimir)).
+* If partition key of a `MergeTree` table does not include `Date` or `DateTime` columns but includes exactly one `DateTime64` column, expose its values in the `min_time` and `max_time` columns in `system.parts` and `system.parts_columns` tables. Add `min_time` and `max_time` columns to `system.parts_columns` table (these was inconsistency to the `system.parts` table). This closes [#18244](https://github.com/ClickHouse/ClickHouse/issues/18244). [#22011](https://github.com/ClickHouse/ClickHouse/pull/22011) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Supported `replication_alter_partitions_sync=1` setting in `clickhouse-copier` for moving partitions from helping table to destination. Decreased default timeouts. Fixes [#21911](https://github.com/ClickHouse/ClickHouse/issues/21911). [#21912](https://github.com/ClickHouse/ClickHouse/pull/21912) ([turbo jason](https://github.com/songenjie)).
+* Show path to data directory of `EmbeddedRocksDB` tables in system tables. [#21903](https://github.com/ClickHouse/ClickHouse/pull/21903) ([tavplubix](https://github.com/tavplubix)).
+* Add profile event `HedgedRequestsChangeReplica`, change read data timeout from sec to ms. [#21886](https://github.com/ClickHouse/ClickHouse/pull/21886) ([Kruglov Pavel](https://github.com/Avogar)).
+* DiskS3 (experimental feature under development). Fixed bug with the impossibility to move directory if the destination is not empty and cache disk is used. [#21837](https://github.com/ClickHouse/ClickHouse/pull/21837) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Better formatting for `Array` and `Map` data types in Web UI. [#21798](https://github.com/ClickHouse/ClickHouse/pull/21798) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Update clusters only if their configurations were updated. [#21685](https://github.com/ClickHouse/ClickHouse/pull/21685) ([Kruglov Pavel](https://github.com/Avogar)).
+* Propagate query and session settings for distributed DDL queries. Set `distributed_ddl_entry_format_version` to 2 to enable this. Added `distributed_ddl_output_mode` setting. Supported modes: `none`, `throw` (default), `null_status_on_timeout` and `never_throw`. Miscellaneous fixes and improvements for `Replicated` database engine. [#21535](https://github.com/ClickHouse/ClickHouse/pull/21535) ([tavplubix](https://github.com/tavplubix)).
+* If `PODArray` was instantiated with element size that is neither a fraction or a multiple of 16, buffer overflow was possible. No bugs in current releases exist. [#21533](https://github.com/ClickHouse/ClickHouse/pull/21533) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add `last_error_time`/`last_error_message`/`last_error_stacktrace`/`remote` columns for `system.errors`. [#21529](https://github.com/ClickHouse/ClickHouse/pull/21529) ([Azat Khuzhin](https://github.com/azat)).
+* Add aliases `simpleJSONExtract/simpleJSONHas` to `visitParam/visitParamExtract{UInt, Int, Bool, Float, Raw, String}`. Fixes #21383. [#21519](https://github.com/ClickHouse/ClickHouse/pull/21519) ([fastio](https://github.com/fastio)).
+* Add setting `optimize_skip_unused_shards_limit` to limit the number of sharding key values for `optimize_skip_unused_shards`. [#21512](https://github.com/ClickHouse/ClickHouse/pull/21512) ([Azat Khuzhin](https://github.com/azat)).
+* Improve `clickhouse-format` to not throw exception when there are extra spaces or comment after the last query, and throw exception early with readable message when format `ASTInsertQuery` with data . [#21311](https://github.com/ClickHouse/ClickHouse/pull/21311) ([flynn](https://github.com/ucasFL)).
+* Improve support of integer keys in data type `Map`. [#21157](https://github.com/ClickHouse/ClickHouse/pull/21157) ([Anton Popov](https://github.com/CurtizJ)).
+* MaterializeMySQL: attempt to reconnect to MySQL if the connection is lost. [#20961](https://github.com/ClickHouse/ClickHouse/pull/20961) ([Håvard Kvålen](https://github.com/havardk)).
+* Support more cases to rewrite `CROSS JOIN` to `INNER JOIN`. [#20392](https://github.com/ClickHouse/ClickHouse/pull/20392) ([Vladimir](https://github.com/vdimir)).
+* Do not create empty parts on INSERT when `optimize_on_insert` setting enabled. Fixes [#20304](https://github.com/ClickHouse/ClickHouse/issues/20304). [#20387](https://github.com/ClickHouse/ClickHouse/pull/20387) ([Kruglov Pavel](https://github.com/Avogar)).
+* `MaterializeMySQL`: add minmax skipping index for `_version` column. [#20382](https://github.com/ClickHouse/ClickHouse/pull/20382) ([Stig Bakken](https://github.com/stigsb)).
+* Add option `--backslash` for `clickhouse-format`, which can add a backslash at the end of each line of the formatted query. [#21494](https://github.com/ClickHouse/ClickHouse/pull/21494) ([flynn](https://github.com/ucasFL)).
+* Now clickhouse will not throw `LOGICAL_ERROR` exception when we try to mutate the already covered part. Fixes [#22013](https://github.com/ClickHouse/ClickHouse/issues/22013). [#22291](https://github.com/ClickHouse/ClickHouse/pull/22291) ([alesapin](https://github.com/alesapin)).
+
+#### Bug Fix
+
+* Remove socket from epoll before cancelling packet receiver in `HedgedConnections` to prevent possible race. Fixes [#22161](https://github.com/ClickHouse/ClickHouse/issues/22161). [#22443](https://github.com/ClickHouse/ClickHouse/pull/22443) ([Kruglov Pavel](https://github.com/Avogar)).
+* Add (missing) memory accounting in parallel parsing routines. In previous versions OOM was possible when the resultset contains very large blocks of data. This closes [#22008](https://github.com/ClickHouse/ClickHouse/issues/22008). [#22425](https://github.com/ClickHouse/ClickHouse/pull/22425) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix exception which may happen when `SELECT` has constant `WHERE` condition and source table has columns which names are digits. [#22270](https://github.com/ClickHouse/ClickHouse/pull/22270) ([LiuNeng](https://github.com/liuneng1994)).
+* Fix query cancellation with `use_hedged_requests=0` and `async_socket_for_remote=1`. [#22183](https://github.com/ClickHouse/ClickHouse/pull/22183) ([Azat Khuzhin](https://github.com/azat)).
+* Fix uncaught exception in `InterserverIOHTTPHandler`. [#22146](https://github.com/ClickHouse/ClickHouse/pull/22146) ([Azat Khuzhin](https://github.com/azat)).
+* Fix docker entrypoint in case `http_port` is not in the config. [#22132](https://github.com/ClickHouse/ClickHouse/pull/22132) ([Ewout](https://github.com/devwout)).
+* Fix error `Invalid number of rows in Chunk` in `JOIN` with `TOTALS` and `arrayJoin`. Closes [#19303](https://github.com/ClickHouse/ClickHouse/issues/19303). [#22129](https://github.com/ClickHouse/ClickHouse/pull/22129) ([Vladimir](https://github.com/vdimir)).
+* Fix the background thread pool name which used to poll message from Kafka. The Kafka engine with the broken thread pool will not consume the message from message queue. [#22122](https://github.com/ClickHouse/ClickHouse/pull/22122) ([fastio](https://github.com/fastio)).
+* Fix waiting for `OPTIMIZE` and `ALTER` queries for `ReplicatedMergeTree` table engines. Now the query will not hang when the table was detached or restarted. [#22118](https://github.com/ClickHouse/ClickHouse/pull/22118) ([alesapin](https://github.com/alesapin)).
+* Disable `async_socket_for_remote`/`use_hedged_requests` for buggy Linux kernels. [#22109](https://github.com/ClickHouse/ClickHouse/pull/22109) ([Azat Khuzhin](https://github.com/azat)).
+* Docker entrypoint: avoid chown of `.` in case when `LOG_PATH` is empty. Closes [#22100](https://github.com/ClickHouse/ClickHouse/issues/22100). [#22102](https://github.com/ClickHouse/ClickHouse/pull/22102) ([filimonov](https://github.com/filimonov)).
+* The function `decrypt` was lacking a check for the minimal size of data encrypted in `AEAD` mode. This closes [#21897](https://github.com/ClickHouse/ClickHouse/issues/21897). [#22064](https://github.com/ClickHouse/ClickHouse/pull/22064) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* In rare case, merge for `CollapsingMergeTree` may create granule with `index_granularity + 1` rows. Because of this, internal check, added in [#18928](https://github.com/ClickHouse/ClickHouse/issues/18928) (affects 21.2 and 21.3), may fail with error `Incomplete granules are not allowed while blocks are granules size`. This error did not allow parts to merge. [#21976](https://github.com/ClickHouse/ClickHouse/pull/21976) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Reverted [#15454](https://github.com/ClickHouse/ClickHouse/issues/15454) that may cause significant increase in memory usage while loading external dictionaries of hashed type. This closes [#21935](https://github.com/ClickHouse/ClickHouse/issues/21935). [#21948](https://github.com/ClickHouse/ClickHouse/pull/21948) ([Maksim Kita](https://github.com/kitaisreal)).
+* Prevent hedged connections overlaps (`Unknown packet 9 from server` error). [#21941](https://github.com/ClickHouse/ClickHouse/pull/21941) ([Azat Khuzhin](https://github.com/azat)).
+* Fix reading the HTTP POST request with "multipart/form-data" content type in some cases. [#21936](https://github.com/ClickHouse/ClickHouse/pull/21936) ([Ivan](https://github.com/abyss7)).
+* Fix wrong `ORDER BY` results when a query contains window functions, and optimization for reading in primary key order is applied. Fixes [#21828](https://github.com/ClickHouse/ClickHouse/issues/21828). [#21915](https://github.com/ClickHouse/ClickHouse/pull/21915) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Fix deadlock in first catboost model execution. Closes [#13832](https://github.com/ClickHouse/ClickHouse/issues/13832). [#21844](https://github.com/ClickHouse/ClickHouse/pull/21844) ([Kruglov Pavel](https://github.com/Avogar)).
+* Fix incorrect query result (and possible crash) which could happen when `WHERE` or `HAVING` condition is pushed before `GROUP BY`. Fixes [#21773](https://github.com/ClickHouse/ClickHouse/issues/21773). [#21841](https://github.com/ClickHouse/ClickHouse/pull/21841) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Better error handling and logging in `WriteBufferFromS3`. [#21836](https://github.com/ClickHouse/ClickHouse/pull/21836) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Fix possible crashes in aggregate functions with combinator `Distinct`, while using two-level aggregation. This is a follow-up fix of [#18365](https://github.com/ClickHouse/ClickHouse/pull/18365) . Can only reproduced in production env. [#21818](https://github.com/ClickHouse/ClickHouse/pull/21818) ([Amos Bird](https://github.com/amosbird)).
+* Fix scalar subquery index analysis. This fixes [#21717](https://github.com/ClickHouse/ClickHouse/issues/21717) , which was introduced in [#18896](https://github.com/ClickHouse/ClickHouse/pull/18896). [#21766](https://github.com/ClickHouse/ClickHouse/pull/21766) ([Amos Bird](https://github.com/amosbird)).
+* Fix bug for `ReplicatedMerge` table engines when `ALTER MODIFY COLUMN` query doesn't change the type of `Decimal` column if its size (32 bit or 64 bit) doesn't change. [#21728](https://github.com/ClickHouse/ClickHouse/pull/21728) ([alesapin](https://github.com/alesapin)).
+* Fix possible infinite waiting when concurrent `OPTIMIZE` and `DROP` are run for `ReplicatedMergeTree`. [#21716](https://github.com/ClickHouse/ClickHouse/pull/21716) ([Azat Khuzhin](https://github.com/azat)).
+* Fix function `arrayElement` with type `Map` for constant integer arguments. [#21699](https://github.com/ClickHouse/ClickHouse/pull/21699) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix SIGSEGV on not existing attributes from `ip_trie` with `access_to_key_from_attributes`. [#21692](https://github.com/ClickHouse/ClickHouse/pull/21692) ([Azat Khuzhin](https://github.com/azat)).
+* Server now start accepting connections only after `DDLWorker` and dictionaries initialization. [#21676](https://github.com/ClickHouse/ClickHouse/pull/21676) ([Azat Khuzhin](https://github.com/azat)).
+* Add type conversion for keys of tables of type `Join` (previously led to SIGSEGV). [#21646](https://github.com/ClickHouse/ClickHouse/pull/21646) ([Azat Khuzhin](https://github.com/azat)).
+* Fix distributed requests cancellation (for example simple select from multiple shards with limit, i.e. `select * from remote('127.{2,3}', system.numbers) limit 100`) with `async_socket_for_remote=1`. [#21643](https://github.com/ClickHouse/ClickHouse/pull/21643) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `fsync_part_directory` for horizontal merge. [#21642](https://github.com/ClickHouse/ClickHouse/pull/21642) ([Azat Khuzhin](https://github.com/azat)).
+* Remove unknown columns from joined table in `WHERE` for queries to external database engines (MySQL, PostgreSQL). close [#14614](https://github.com/ClickHouse/ClickHouse/issues/14614), close [#19288](https://github.com/ClickHouse/ClickHouse/issues/19288) (dup), close [#19645](https://github.com/ClickHouse/ClickHouse/issues/19645) (dup). [#21640](https://github.com/ClickHouse/ClickHouse/pull/21640) ([Vladimir](https://github.com/vdimir)).
+* `std::terminate` was called if there is an error writing data into s3. [#21624](https://github.com/ClickHouse/ClickHouse/pull/21624) ([Vladimir](https://github.com/vdimir)).
+* Fix possible error `Cannot find column` when `optimize_skip_unused_shards` is enabled and zero shards are used. [#21579](https://github.com/ClickHouse/ClickHouse/pull/21579) ([Azat Khuzhin](https://github.com/azat)).
+* In case if query has constant `WHERE` condition, and setting `optimize_skip_unused_shards` enabled, all shards may be skipped and query could return incorrect empty result. [#21550](https://github.com/ClickHouse/ClickHouse/pull/21550) ([Amos Bird](https://github.com/amosbird)).
+* Fix table function `clusterAllReplicas` returns wrong `_shard_num`. close [#21481](https://github.com/ClickHouse/ClickHouse/issues/21481). [#21498](https://github.com/ClickHouse/ClickHouse/pull/21498) ([flynn](https://github.com/ucasFL)).
+* Fix that S3 table holds old credentials after config update. [#21457](https://github.com/ClickHouse/ClickHouse/pull/21457) ([Grigory Pervakov](https://github.com/GrigoryPervakov)).
+* Fixed race on SSL object inside `SecureSocket` in Poco. [#21456](https://github.com/ClickHouse/ClickHouse/pull/21456) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix `Avro` format parsing for `Kafka`. Fixes [#21437](https://github.com/ClickHouse/ClickHouse/issues/21437). [#21438](https://github.com/ClickHouse/ClickHouse/pull/21438) ([Ilya Golshtein](https://github.com/ilejn)).
+* Fix receive and send timeouts and non-blocking read in secure socket. [#21429](https://github.com/ClickHouse/ClickHouse/pull/21429) ([Kruglov Pavel](https://github.com/Avogar)).
+* `force_drop_table` flag didn't work for `MATERIALIZED VIEW`, it's fixed. Fixes [#18943](https://github.com/ClickHouse/ClickHouse/issues/18943). [#20626](https://github.com/ClickHouse/ClickHouse/pull/20626) ([tavplubix](https://github.com/tavplubix)).
+* Fix name clashes in `PredicateRewriteVisitor`. It caused incorrect `WHERE` filtration after full join. Close [#20497](https://github.com/ClickHouse/ClickHouse/issues/20497). [#20622](https://github.com/ClickHouse/ClickHouse/pull/20622) ([Vladimir](https://github.com/vdimir)).
+
+#### Build/Testing/Packaging Improvement
+
+* Add [Jepsen](https://github.com/jepsen-io/jepsen) tests for ClickHouse Keeper. [#21677](https://github.com/ClickHouse/ClickHouse/pull/21677) ([alesapin](https://github.com/alesapin)).
+* Run stateless tests in parallel in CI. Depends on [#22181](https://github.com/ClickHouse/ClickHouse/issues/22181). [#22300](https://github.com/ClickHouse/ClickHouse/pull/22300) ([alesapin](https://github.com/alesapin)).
+* Enable status check for [SQLancer](https://github.com/sqlancer/sqlancer) CI run. [#22015](https://github.com/ClickHouse/ClickHouse/pull/22015) ([Ilya Yatsishin](https://github.com/qoega)).
+* Multiple preparations for PowerPC builds: Enable the bundled openldap on `ppc64le`. [#22487](https://github.com/ClickHouse/ClickHouse/pull/22487) ([Kfir Itzhak](https://github.com/mastertheknife)).  Enable compiling on `ppc64le` with Clang. [#22476](https://github.com/ClickHouse/ClickHouse/pull/22476) ([Kfir Itzhak](https://github.com/mastertheknife)). Fix compiling boost on `ppc64le`. [#22474](https://github.com/ClickHouse/ClickHouse/pull/22474) ([Kfir Itzhak](https://github.com/mastertheknife)). Fix CMake error about internal CMake variable `CMAKE_ASM_COMPILE_OBJECT` not set on `ppc64le`. [#22469](https://github.com/ClickHouse/ClickHouse/pull/22469) ([Kfir Itzhak](https://github.com/mastertheknife)). Fix Fedora/RHEL/CentOS not finding `libclang_rt.builtins` on `ppc64le`. [#22458](https://github.com/ClickHouse/ClickHouse/pull/22458) ([Kfir Itzhak](https://github.com/mastertheknife)).  Enable building with `jemalloc` on `ppc64le`. [#22447](https://github.com/ClickHouse/ClickHouse/pull/22447) ([Kfir Itzhak](https://github.com/mastertheknife)). Fix ClickHouse's config embedding and cctz's timezone embedding on `ppc64le`. [#22445](https://github.com/ClickHouse/ClickHouse/pull/22445) ([Kfir Itzhak](https://github.com/mastertheknife)). Fixed compiling on `ppc64le` and use the correct instruction pointer register on `ppc64le`. [#22430](https://github.com/ClickHouse/ClickHouse/pull/22430) ([Kfir Itzhak](https://github.com/mastertheknife)).
+* Re-enable the S3 (AWS) library on `aarch64`. [#22484](https://github.com/ClickHouse/ClickHouse/pull/22484) ([Kfir Itzhak](https://github.com/mastertheknife)).
+* Add `tzdata` to Docker containers because reading `ORC` formats requires it. This closes [#14156](https://github.com/ClickHouse/ClickHouse/issues/14156). [#22000](https://github.com/ClickHouse/ClickHouse/pull/22000) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Introduce 2 arguments for `clickhouse-server` image Dockerfile: `deb_location` & `single_binary_location`. [#21977](https://github.com/ClickHouse/ClickHouse/pull/21977) ([filimonov](https://github.com/filimonov)).
+* Allow to use clang-tidy with release builds by enabling assertions if it is used. [#21914](https://github.com/ClickHouse/ClickHouse/pull/21914) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add llvm-12 binaries name to search in cmake scripts. Implicit constants conversions to mute clang warnings. Updated submodules to build with CMake 3.19. Mute recursion in macro expansion in `readpassphrase` library. Deprecated `-fuse-ld` changed to `--ld-path` for clang. [#21597](https://github.com/ClickHouse/ClickHouse/pull/21597) ([Ilya Yatsishin](https://github.com/qoega)).
+* Updating `docker/test/testflows/runner/dockerd-entrypoint.sh` to use Yandex dockerhub-proxy, because Docker Hub has enabled very restrictive rate limits [#21551](https://github.com/ClickHouse/ClickHouse/pull/21551) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Fix macOS shared lib build. [#20184](https://github.com/ClickHouse/ClickHouse/pull/20184) ([nvartolomei](https://github.com/nvartolomei)).
+* Add `ctime` option to `zookeeper-dump-tree`. It allows to dump node creation time. [#21842](https://github.com/ClickHouse/ClickHouse/pull/21842) ([Ilya](https://github.com/HumanUser)).
+
+
+## ClickHouse release 21.3 (LTS)
+
+### ClickHouse release v21.3, 2021-03-12
+
+#### Backward Incompatible Change
+
+* Now it's not allowed to create MergeTree tables in old syntax with table TTL because it's just ignored. Attach of old tables is still possible. [#20282](https://github.com/ClickHouse/ClickHouse/pull/20282) ([alesapin](https://github.com/alesapin)).
+* Now all case-insensitive function names will be rewritten to their canonical representations. This is needed for projection query routing (the upcoming feature). [#20174](https://github.com/ClickHouse/ClickHouse/pull/20174) ([Amos Bird](https://github.com/amosbird)).
+* Fix creation of `TTL` in cases, when its expression is a function and it is the same as `ORDER BY` key. Now it's allowed to set custom aggregation to primary key columns in `TTL` with `GROUP BY`. Backward incompatible: For primary key columns, which are not in `GROUP BY` and aren't set explicitly now is applied function `any` instead of `max`, when TTL is expired. Also if you use TTL with `WHERE` or `GROUP BY` you can see exceptions at merges, while making rolling update. [#15450](https://github.com/ClickHouse/ClickHouse/pull/15450) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### New Feature
+
+* Add file engine settings: `engine_file_empty_if_not_exists` and `engine_file_truncate_on_insert`. [#20620](https://github.com/ClickHouse/ClickHouse/pull/20620) ([M0r64n](https://github.com/M0r64n)).
+* Add aggregate function `deltaSum` for summing the differences between consecutive rows. [#20057](https://github.com/ClickHouse/ClickHouse/pull/20057) ([Russ Frank](https://github.com/rf)).
+* New `event_time_microseconds` column in `system.part_log` table. [#20027](https://github.com/ClickHouse/ClickHouse/pull/20027) ([Bharat Nallan](https://github.com/bharatnc)).
+* Added `timezoneOffset(datetime)` function which will give the offset from UTC in seconds. This close [#issue:19850](https://github.com/ClickHouse/ClickHouse/issues/19850). [#19962](https://github.com/ClickHouse/ClickHouse/pull/19962) ([keenwolf](https://github.com/keen-wolf)).
+* Add setting `insert_shard_id` to support insert data into specific shard from distributed table. [#19961](https://github.com/ClickHouse/ClickHouse/pull/19961) ([flynn](https://github.com/ucasFL)).
+* Function `reinterpretAs` updated to support big integers. Fixes [#19691](https://github.com/ClickHouse/ClickHouse/issues/19691). [#19858](https://github.com/ClickHouse/ClickHouse/pull/19858) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added Server Side Encryption Customer Keys (the `x-amz-server-side-encryption-customer-(key/md5)` header) support in S3 client. See [the link](https://docs.aws.amazon.com/AmazonS3/latest/dev/ServerSideEncryptionCustomerKeys.html). Closes [#19428](https://github.com/ClickHouse/ClickHouse/issues/19428). [#19748](https://github.com/ClickHouse/ClickHouse/pull/19748) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Added `implicit_key` option for `executable` dictionary source. It allows to avoid printing key for every record if records comes in the same order as the input keys. Implements [#14527](https://github.com/ClickHouse/ClickHouse/issues/14527). [#19677](https://github.com/ClickHouse/ClickHouse/pull/19677) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add quota type `query_selects` and `query_inserts`. [#19603](https://github.com/ClickHouse/ClickHouse/pull/19603) ([JackyWoo](https://github.com/JackyWoo)).
+* Add function `extractTextFromHTML` [#19600](https://github.com/ClickHouse/ClickHouse/pull/19600) ([zlx19950903](https://github.com/zlx19950903)), ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Tables with `MergeTree*` engine now have two new table-level settings for query concurrency control. Setting `max_concurrent_queries` limits the number of concurrently executed queries which are related to this table. Setting `min_marks_to_honor_max_concurrent_queries` tells to apply previous setting only if query reads at least this number of marks. [#19544](https://github.com/ClickHouse/ClickHouse/pull/19544) ([Amos Bird](https://github.com/amosbird)).
+* Added `file` function to read file from user_files directory as a String. This is different from the `file` table function. This implements [#issue:18851](https://github.com/ClickHouse/ClickHouse/issues/18851). [#19204](https://github.com/ClickHouse/ClickHouse/pull/19204) ([keenwolf](https://github.com/keen-wolf)).
+
+#### Experimental feature
+
+* Add experimental `Replicated` database engine. It replicates DDL queries across multiple hosts. [#16193](https://github.com/ClickHouse/ClickHouse/pull/16193) ([tavplubix](https://github.com/tavplubix)).
+* Introduce experimental support for window functions, enabled with `allow_experimental_window_functions = 1`. This is a preliminary, alpha-quality implementation that is not suitable for production use and will change in backward-incompatible ways in future releases. Please see [the documentation](https://github.com/ClickHouse/ClickHouse/blob/master/docs/en/sql-reference/window-functions/index.md#experimental-window-functions) for the list of supported features. [#20337](https://github.com/ClickHouse/ClickHouse/pull/20337) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Add the ability to backup/restore metadata files for DiskS3. [#18377](https://github.com/ClickHouse/ClickHouse/pull/18377) ([Pavel Kovalenko](https://github.com/Jokser)).
+
+#### Performance Improvement
+
+* Hedged requests for remote queries. When setting `use_hedged_requests` enabled (off by default), allow to establish many connections with different replicas for query. New connection is enabled in case existent connection(s) with replica(s) were not established within `hedged_connection_timeout` or no data was received within `receive_data_timeout`. Query uses the first connection which send non empty progress packet (or data packet, if `allow_changing_replica_until_first_data_packet`); other connections are cancelled. Queries with `max_parallel_replicas > 1` are supported. [#19291](https://github.com/ClickHouse/ClickHouse/pull/19291) ([Kruglov Pavel](https://github.com/Avogar)). This allows to significantly reduce tail latencies on very large clusters.
+* Added support for `PREWHERE` (and enable the corresponding optimization) when tables have row-level security expressions specified. [#19576](https://github.com/ClickHouse/ClickHouse/pull/19576) ([Denis Glazachev](https://github.com/traceon)).
+* The setting `distributed_aggregation_memory_efficient` is enabled by default. It will lower memory usage and improve performance of distributed queries. [#20599](https://github.com/ClickHouse/ClickHouse/pull/20599) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve performance of GROUP BY multiple fixed size keys. [#20472](https://github.com/ClickHouse/ClickHouse/pull/20472) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve performance of aggregate functions by more strict aliasing. [#19946](https://github.com/ClickHouse/ClickHouse/pull/19946) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Speed up reading from `Memory` tables in extreme cases (when reading speed is in order of 50 GB/sec) by simplification of pipeline and (consequently) less lock contention in pipeline scheduling. [#20468](https://github.com/ClickHouse/ClickHouse/pull/20468) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Partially reimplement HTTP server to make it making less copies of incoming and outgoing data. It gives up to 1.5 performance improvement on inserting long records over HTTP. [#19516](https://github.com/ClickHouse/ClickHouse/pull/19516) ([Ivan](https://github.com/abyss7)).
+* Add `compress` setting for `Memory` tables. If it's enabled the table will use less RAM. On some machines and datasets it can also work faster on SELECT, but it is not always the case. This closes [#20093](https://github.com/ClickHouse/ClickHouse/issues/20093). Note: there are reasons why Memory tables can work slower than MergeTree: (1) lack of compression (2) static size of blocks (3) lack of indices and prewhere... [#20168](https://github.com/ClickHouse/ClickHouse/pull/20168) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Slightly better code in aggregation. [#20978](https://github.com/ClickHouse/ClickHouse/pull/20978) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add back `intDiv`/`modulo` specializations for better performance. This fixes [#21293](https://github.com/ClickHouse/ClickHouse/issues/21293) . The regression was introduced in https://github.com/ClickHouse/ClickHouse/pull/18145 . [#21307](https://github.com/ClickHouse/ClickHouse/pull/21307) ([Amos Bird](https://github.com/amosbird)).
+* Do not squash blocks too much on INSERT SELECT if inserting into Memory table. In previous versions inefficient data representation was created in Memory table after INSERT SELECT. This closes [#13052](https://github.com/ClickHouse/ClickHouse/issues/13052). [#20169](https://github.com/ClickHouse/ClickHouse/pull/20169) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix at least one case when DataType parser may have exponential complexity (found by fuzzer). This closes [#20096](https://github.com/ClickHouse/ClickHouse/issues/20096). [#20132](https://github.com/ClickHouse/ClickHouse/pull/20132) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Parallelize SELECT with FINAL for single part with level > 0 when `do_not_merge_across_partitions_select_final` setting is 1. [#19375](https://github.com/ClickHouse/ClickHouse/pull/19375) ([Kruglov Pavel](https://github.com/Avogar)).
+* Fill only requested columns when querying `system.parts` and `system.parts_columns`. Closes [#19570](https://github.com/ClickHouse/ClickHouse/issues/19570). [#21035](https://github.com/ClickHouse/ClickHouse/pull/21035) ([Anmol Arora](https://github.com/anmolarora)).
+* Perform algebraic optimizations of arithmetic expressions inside `avg` aggregate function. close [#20092](https://github.com/ClickHouse/ClickHouse/issues/20092). [#20183](https://github.com/ClickHouse/ClickHouse/pull/20183) ([flynn](https://github.com/ucasFL)).
+
+#### Improvement
+
+* Case-insensitive compression methods for table functions. Also fixed LZMA compression method which was checked in upper case. [#21416](https://github.com/ClickHouse/ClickHouse/pull/21416) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Add two settings to delay or throw error during insertion when there are too many inactive parts. This is useful when server fails to clean up parts quickly enough. [#20178](https://github.com/ClickHouse/ClickHouse/pull/20178) ([Amos Bird](https://github.com/amosbird)).
+* Provide better compatibility for mysql clients. 1. mysql jdbc 2. mycli. [#21367](https://github.com/ClickHouse/ClickHouse/pull/21367) ([Amos Bird](https://github.com/amosbird)).
+* Forbid to drop a column if it's referenced by materialized view. Closes [#21164](https://github.com/ClickHouse/ClickHouse/issues/21164). [#21303](https://github.com/ClickHouse/ClickHouse/pull/21303) ([flynn](https://github.com/ucasFL)).
+* MySQL dictionary source will now retry unexpected connection failures (Lost connection to MySQL server during query) which sometimes happen on SSL/TLS connections. [#21237](https://github.com/ClickHouse/ClickHouse/pull/21237) ([Alexander Kazakov](https://github.com/Akazz)).
+* Usability improvement: more consistent `DateTime64` parsing: recognize the case when unix timestamp with subsecond resolution is specified as scaled integer (like `1111111111222` instead of `1111111111.222`). This closes [#13194](https://github.com/ClickHouse/ClickHouse/issues/13194). [#21053](https://github.com/ClickHouse/ClickHouse/pull/21053) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Do only merging of sorted blocks on initiator with distributed_group_by_no_merge. [#20882](https://github.com/ClickHouse/ClickHouse/pull/20882) ([Azat Khuzhin](https://github.com/azat)).
+* When loading config for mysql source ClickHouse will now randomize the list of replicas with the same priority to ensure the round-robin logics of picking mysql endpoint. This closes [#20629](https://github.com/ClickHouse/ClickHouse/issues/20629). [#20632](https://github.com/ClickHouse/ClickHouse/pull/20632) ([Alexander Kazakov](https://github.com/Akazz)).
+* Function 'reinterpretAs(x, Type)' renamed into 'reinterpret(x, Type)'. [#20611](https://github.com/ClickHouse/ClickHouse/pull/20611) ([Maksim Kita](https://github.com/kitaisreal)).
+* Support vhost for RabbitMQ engine [#20576](https://github.com/ClickHouse/ClickHouse/issues/20576). [#20596](https://github.com/ClickHouse/ClickHouse/pull/20596) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Improved serialization for data types combined of Arrays and Tuples. Improved matching enum data types to protobuf enum type. Fixed serialization of the `Map` data type. Omitted values are now set by default. [#20506](https://github.com/ClickHouse/ClickHouse/pull/20506) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fixed race between execution of distributed DDL tasks and cleanup of DDL queue. Now DDL task cannot be removed from ZooKeeper if there are active workers. Fixes [#20016](https://github.com/ClickHouse/ClickHouse/issues/20016). [#20448](https://github.com/ClickHouse/ClickHouse/pull/20448) ([tavplubix](https://github.com/tavplubix)).
+* Make FQDN and other DNS related functions work correctly in alpine images. [#20336](https://github.com/ClickHouse/ClickHouse/pull/20336) ([filimonov](https://github.com/filimonov)).
+* Do not allow early constant folding of explicitly forbidden functions. [#20303](https://github.com/ClickHouse/ClickHouse/pull/20303) ([Azat Khuzhin](https://github.com/azat)).
+* Implicit conversion from integer to Decimal type might succeeded if integer value doe not fit into Decimal type. Now it throws `ARGUMENT_OUT_OF_BOUND`. [#20232](https://github.com/ClickHouse/ClickHouse/pull/20232) ([tavplubix](https://github.com/tavplubix)).
+* Lockless `SYSTEM FLUSH DISTRIBUTED`. [#20215](https://github.com/ClickHouse/ClickHouse/pull/20215) ([Azat Khuzhin](https://github.com/azat)).
+* Normalize count(constant), sum(1) to count(). This is needed for projection query routing. [#20175](https://github.com/ClickHouse/ClickHouse/pull/20175) ([Amos Bird](https://github.com/amosbird)).
+* Support all native integer types in bitmap functions. [#20171](https://github.com/ClickHouse/ClickHouse/pull/20171) ([Amos Bird](https://github.com/amosbird)).
+* Updated `CacheDictionary`, `ComplexCacheDictionary`, `SSDCacheDictionary`, `SSDComplexKeyDictionary` to use LRUHashMap as underlying index. [#20164](https://github.com/ClickHouse/ClickHouse/pull/20164) ([Maksim Kita](https://github.com/kitaisreal)).
+* The setting `access_management` is now configurable on startup by providing `CLICKHOUSE_DEFAULT_ACCESS_MANAGEMENT`, defaults to disabled (`0`) which was the prior value. [#20139](https://github.com/ClickHouse/ClickHouse/pull/20139) ([Marquitos](https://github.com/sonirico)).
+* Fix toDateTime64(toDate()/toDateTime()) for DateTime64 - Implement DateTime64 clamping to match DateTime behaviour. [#20131](https://github.com/ClickHouse/ClickHouse/pull/20131) ([Azat Khuzhin](https://github.com/azat)).
+* Quota improvements: SHOW TABLES is now considered as one query in the quota calculations, not two queries. SYSTEM queries now consume quota. Fix calculation of interval's end in quota consumption. [#20106](https://github.com/ClickHouse/ClickHouse/pull/20106) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Supports `path IN (set)` expressions for `system.zookeeper` table. [#20105](https://github.com/ClickHouse/ClickHouse/pull/20105) ([小路](https://github.com/nicelulu)).
+* Show full details of `MaterializeMySQL` tables in `system.tables`. [#20051](https://github.com/ClickHouse/ClickHouse/pull/20051) ([Stig Bakken](https://github.com/stigsb)).
+* Fix data race in executable dictionary that was possible only on misuse (when the script returns data ignoring its input). [#20045](https://github.com/ClickHouse/ClickHouse/pull/20045) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* The value of MYSQL_OPT_RECONNECT option can now be controlled by "opt_reconnect" parameter in the config section of mysql replica. [#19998](https://github.com/ClickHouse/ClickHouse/pull/19998) ([Alexander Kazakov](https://github.com/Akazz)).
+* If user calls `JSONExtract` function with `Float32` type requested, allow inaccurate conversion to the result type. For example the number `0.1` in JSON is double precision and is not representable in Float32, but the user still wants to get it. Previous versions return 0 for non-Nullable type and NULL for Nullable type to indicate that conversion is imprecise. The logic was 100% correct but it was surprising to users and leading to questions. This closes [#13962](https://github.com/ClickHouse/ClickHouse/issues/13962). [#19960](https://github.com/ClickHouse/ClickHouse/pull/19960) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add conversion of block structure for INSERT into Distributed tables if it does not match. [#19947](https://github.com/ClickHouse/ClickHouse/pull/19947) ([Azat Khuzhin](https://github.com/azat)).
+* Improvement for the `system.distributed_ddl_queue` table. Initialize MaxDDLEntryID to the last value after restarting. Before this PR, MaxDDLEntryID will remain zero until a new DDLTask is processed. [#19924](https://github.com/ClickHouse/ClickHouse/pull/19924) ([Amos Bird](https://github.com/amosbird)).
+* Show `MaterializeMySQL` tables in `system.parts`. [#19770](https://github.com/ClickHouse/ClickHouse/pull/19770) ([Stig Bakken](https://github.com/stigsb)).
+* Add separate config directive for `Buffer` profile. [#19721](https://github.com/ClickHouse/ClickHouse/pull/19721) ([Azat Khuzhin](https://github.com/azat)).
+* Move conditions that are not related to JOIN to WHERE clause. [#18720](https://github.com/ClickHouse/ClickHouse/issues/18720). [#19685](https://github.com/ClickHouse/ClickHouse/pull/19685) ([hexiaoting](https://github.com/hexiaoting)).
+* Add ability to throttle INSERT into Distributed based on amount of pending bytes for async send (`bytes_to_delay_insert`/`max_delay_to_insert` and `bytes_to_throw_insert` settings for `Distributed` engine has been added). [#19673](https://github.com/ClickHouse/ClickHouse/pull/19673) ([Azat Khuzhin](https://github.com/azat)).
+* Fix some rare cases when write errors can be ignored in destructors. [#19451](https://github.com/ClickHouse/ClickHouse/pull/19451) ([Azat Khuzhin](https://github.com/azat)).
+* Print inline frames in stack traces for fatal errors. [#19317](https://github.com/ClickHouse/ClickHouse/pull/19317) ([Ivan](https://github.com/abyss7)).
+
+#### Bug Fix
+
+* Fix redundant reconnects to ZooKeeper and the possibility of two active sessions for a single clickhouse server. Both problems introduced in #14678. [#21264](https://github.com/ClickHouse/ClickHouse/pull/21264) ([alesapin](https://github.com/alesapin)).
+* Fix error `Bad cast from type ... to DB::ColumnLowCardinality` while inserting into table with `LowCardinality` column from `Values` format. Fixes #21140 [#21357](https://github.com/ClickHouse/ClickHouse/pull/21357) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix a deadlock in `ALTER DELETE` mutations for non replicated MergeTree table engines when the predicate contains the table itself. Fixes [#20558](https://github.com/ClickHouse/ClickHouse/issues/20558). [#21477](https://github.com/ClickHouse/ClickHouse/pull/21477) ([alesapin](https://github.com/alesapin)).
+* Fix SIGSEGV for distributed queries on failures. [#21434](https://github.com/ClickHouse/ClickHouse/pull/21434) ([Azat Khuzhin](https://github.com/azat)).
+* Now `ALTER MODIFY COLUMN` queries will correctly affect changes in partition key, skip indices, TTLs, and so on. Fixes [#13675](https://github.com/ClickHouse/ClickHouse/issues/13675). [#21334](https://github.com/ClickHouse/ClickHouse/pull/21334) ([alesapin](https://github.com/alesapin)).
+* Fix bug with `join_use_nulls` and joining `TOTALS` from subqueries. This closes [#19362](https://github.com/ClickHouse/ClickHouse/issues/19362) and [#21137](https://github.com/ClickHouse/ClickHouse/issues/21137). [#21248](https://github.com/ClickHouse/ClickHouse/pull/21248) ([vdimir](https://github.com/vdimir)).
+* Fix crash in `EXPLAIN` for query with `UNION`. Fixes [#20876](https://github.com/ClickHouse/ClickHouse/issues/20876), [#21170](https://github.com/ClickHouse/ClickHouse/issues/21170). [#21246](https://github.com/ClickHouse/ClickHouse/pull/21246) ([flynn](https://github.com/ucasFL)).
+* Now mutations allowed only for table engines that support them (MergeTree family, Memory, MaterializedView). Other engines will report a more clear error. Fixes [#21168](https://github.com/ClickHouse/ClickHouse/issues/21168). [#21183](https://github.com/ClickHouse/ClickHouse/pull/21183) ([alesapin](https://github.com/alesapin)).
+* Fixes [#21112](https://github.com/ClickHouse/ClickHouse/issues/21112). Fixed bug that could cause duplicates with insert query (if one of the callbacks came a little too late). [#21138](https://github.com/ClickHouse/ClickHouse/pull/21138) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix `input_format_null_as_default` take effective when types are nullable. This fixes [#21116](https://github.com/ClickHouse/ClickHouse/issues/21116) . [#21121](https://github.com/ClickHouse/ClickHouse/pull/21121) ([Amos Bird](https://github.com/amosbird)).
+* fix bug related to cast Tuple to Map. Closes [#21029](https://github.com/ClickHouse/ClickHouse/issues/21029). [#21120](https://github.com/ClickHouse/ClickHouse/pull/21120) ([hexiaoting](https://github.com/hexiaoting)).
+* Fix the metadata leak when the Replicated*MergeTree with custom (non default) ZooKeeper cluster is dropped. [#21119](https://github.com/ClickHouse/ClickHouse/pull/21119) ([fastio](https://github.com/fastio)).
+* Fix type mismatch issue when using LowCardinality keys in joinGet. This fixes [#21114](https://github.com/ClickHouse/ClickHouse/issues/21114). [#21117](https://github.com/ClickHouse/ClickHouse/pull/21117) ([Amos Bird](https://github.com/amosbird)).
+* fix default_replica_path and default_replica_name values are useless on Replicated(*)MergeTree engine when the engine needs specify other parameters. [#21060](https://github.com/ClickHouse/ClickHouse/pull/21060) ([mxzlxy](https://github.com/mxzlxy)).
+* Out of bound memory access was possible when formatting specifically crafted out of range value of type `DateTime64`. This closes [#20494](https://github.com/ClickHouse/ClickHouse/issues/20494). This closes [#20543](https://github.com/ClickHouse/ClickHouse/issues/20543). [#21023](https://github.com/ClickHouse/ClickHouse/pull/21023) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Block parallel insertions into storage join. [#21009](https://github.com/ClickHouse/ClickHouse/pull/21009) ([vdimir](https://github.com/vdimir)).
+* Fixed behaviour, when `ALTER MODIFY COLUMN` created mutation, that will knowingly fail. [#21007](https://github.com/ClickHouse/ClickHouse/pull/21007) ([Anton Popov](https://github.com/CurtizJ)).
+* Closes [#9969](https://github.com/ClickHouse/ClickHouse/issues/9969). Fixed Brotli http compression error, which reproduced for large data sizes, slightly complicated structure and with json output format. Update Brotli to the latest version to include the "fix rare access to uninitialized data in ring-buffer". [#20991](https://github.com/ClickHouse/ClickHouse/pull/20991) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Fix 'Empty task was returned from async task queue' on query cancellation. [#20881](https://github.com/ClickHouse/ClickHouse/pull/20881) ([Azat Khuzhin](https://github.com/azat)).
+* `USE database;` query did not work when using MySQL 5.7 client to connect to ClickHouse server, it's fixed. Fixes [#18926](https://github.com/ClickHouse/ClickHouse/issues/18926). [#20878](https://github.com/ClickHouse/ClickHouse/pull/20878) ([tavplubix](https://github.com/tavplubix)).
+* Fix usage of `-Distinct` combinator with `-State` combinator in aggregate functions. [#20866](https://github.com/ClickHouse/ClickHouse/pull/20866) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix subquery with union distinct and limit clause. close [#20597](https://github.com/ClickHouse/ClickHouse/issues/20597). [#20610](https://github.com/ClickHouse/ClickHouse/pull/20610) ([flynn](https://github.com/ucasFL)).
+* Fixed inconsistent behavior of dictionary in case of queries where we look for absent keys in dictionary. [#20578](https://github.com/ClickHouse/ClickHouse/pull/20578) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix the number of threads for scalar subqueries and subqueries for index (after [#19007](https://github.com/ClickHouse/ClickHouse/issues/19007) single thread was always used). Fixes [#20457](https://github.com/ClickHouse/ClickHouse/issues/20457), [#20512](https://github.com/ClickHouse/ClickHouse/issues/20512). [#20550](https://github.com/ClickHouse/ClickHouse/pull/20550) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix crash which could happen if unknown packet was received from remove query (was introduced in [#17868](https://github.com/ClickHouse/ClickHouse/issues/17868)). [#20547](https://github.com/ClickHouse/ClickHouse/pull/20547) ([Azat Khuzhin](https://github.com/azat)).
+* Add proper checks while parsing directory names for async INSERT (fixes SIGSEGV). [#20498](https://github.com/ClickHouse/ClickHouse/pull/20498) ([Azat Khuzhin](https://github.com/azat)).
+* Fix function `transform` does not work properly for floating point keys. Closes [#20460](https://github.com/ClickHouse/ClickHouse/issues/20460). [#20479](https://github.com/ClickHouse/ClickHouse/pull/20479) ([flynn](https://github.com/ucasFL)).
+* Fix infinite loop when propagating WITH aliases to subqueries. This fixes [#20388](https://github.com/ClickHouse/ClickHouse/issues/20388). [#20476](https://github.com/ClickHouse/ClickHouse/pull/20476) ([Amos Bird](https://github.com/amosbird)).
+* Fix abnormal server termination when http client goes away. [#20464](https://github.com/ClickHouse/ClickHouse/pull/20464) ([Azat Khuzhin](https://github.com/azat)).
+* Fix `LOGICAL_ERROR` for `join_use_nulls=1` when JOIN contains const from SELECT. [#20461](https://github.com/ClickHouse/ClickHouse/pull/20461) ([Azat Khuzhin](https://github.com/azat)).
+* Check if table function `view` is used in expression list and throw an error. This fixes [#20342](https://github.com/ClickHouse/ClickHouse/issues/20342). [#20350](https://github.com/ClickHouse/ClickHouse/pull/20350) ([Amos Bird](https://github.com/amosbird)).
+* Avoid invalid dereference in RANGE_HASHED() dictionary. [#20345](https://github.com/ClickHouse/ClickHouse/pull/20345) ([Azat Khuzhin](https://github.com/azat)).
+* Fix null dereference with `join_use_nulls=1`. [#20344](https://github.com/ClickHouse/ClickHouse/pull/20344) ([Azat Khuzhin](https://github.com/azat)).
+* Fix incorrect result of binary operations between two constant decimals of different scale. Fixes [#20283](https://github.com/ClickHouse/ClickHouse/issues/20283). [#20339](https://github.com/ClickHouse/ClickHouse/pull/20339) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix too often retries of failed background tasks for `ReplicatedMergeTree` table engines family. This could lead to too verbose logging and increased CPU load. Fixes [#20203](https://github.com/ClickHouse/ClickHouse/issues/20203). [#20335](https://github.com/ClickHouse/ClickHouse/pull/20335) ([alesapin](https://github.com/alesapin)).
+* Restrict to `DROP` or `RENAME` version column of `*CollapsingMergeTree` and `ReplacingMergeTree` table engines. [#20300](https://github.com/ClickHouse/ClickHouse/pull/20300) ([alesapin](https://github.com/alesapin)).
+* Fixed the behavior when in case of broken JSON we tried to read the whole file into memory which leads to exception from the allocator. Fixes [#19719](https://github.com/ClickHouse/ClickHouse/issues/19719). [#20286](https://github.com/ClickHouse/ClickHouse/pull/20286) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix exception during vertical merge for `MergeTree` table engines family which don't allow to perform vertical merges. Fixes [#20259](https://github.com/ClickHouse/ClickHouse/issues/20259). [#20279](https://github.com/ClickHouse/ClickHouse/pull/20279) ([alesapin](https://github.com/alesapin)).
+* Fix rare server crash on config reload during the shutdown. Fixes [#19689](https://github.com/ClickHouse/ClickHouse/issues/19689). [#20224](https://github.com/ClickHouse/ClickHouse/pull/20224) ([alesapin](https://github.com/alesapin)).
+* Fix CTE when using in INSERT SELECT. This fixes [#20187](https://github.com/ClickHouse/ClickHouse/issues/20187), fixes [#20195](https://github.com/ClickHouse/ClickHouse/issues/20195). [#20211](https://github.com/ClickHouse/ClickHouse/pull/20211) ([Amos Bird](https://github.com/amosbird)).
+* Fixes [#19314](https://github.com/ClickHouse/ClickHouse/issues/19314). [#20156](https://github.com/ClickHouse/ClickHouse/pull/20156) ([Ivan](https://github.com/abyss7)).
+* fix toMinute function to handle special timezone correctly. [#20149](https://github.com/ClickHouse/ClickHouse/pull/20149) ([keenwolf](https://github.com/keen-wolf)).
+* Fix server crash after query with `if` function with `Tuple` type of then/else branches result. `Tuple` type must contain `Array` or another complex type. Fixes [#18356](https://github.com/ClickHouse/ClickHouse/issues/18356). [#20133](https://github.com/ClickHouse/ClickHouse/pull/20133) ([alesapin](https://github.com/alesapin)).
+* The `MongoDB` table engine now establishes connection only when it's going to read data. `ATTACH TABLE` won't try to connect anymore. [#20110](https://github.com/ClickHouse/ClickHouse/pull/20110) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Bugfix in StorageJoin. [#20079](https://github.com/ClickHouse/ClickHouse/pull/20079) ([vdimir](https://github.com/vdimir)).
+* Fix the case when calculating modulo of division of negative number by small divisor, the resulting data type was not large enough to accomodate the negative result. This closes [#20052](https://github.com/ClickHouse/ClickHouse/issues/20052). [#20067](https://github.com/ClickHouse/ClickHouse/pull/20067) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* MaterializeMySQL: Fix replication for statements that update several tables. [#20066](https://github.com/ClickHouse/ClickHouse/pull/20066) ([Håvard Kvålen](https://github.com/havardk)).
+* Prevent "Connection refused" in docker during initialization script execution. [#20012](https://github.com/ClickHouse/ClickHouse/pull/20012) ([filimonov](https://github.com/filimonov)).
+* `EmbeddedRocksDB` is an experimental storage. Fix the issue with lack of proper type checking. Simplified code. This closes [#19967](https://github.com/ClickHouse/ClickHouse/issues/19967). [#19972](https://github.com/ClickHouse/ClickHouse/pull/19972) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix a segfault in function `fromModifiedJulianDay` when the argument type is `Nullable(T)` for any integral types other than Int32. [#19959](https://github.com/ClickHouse/ClickHouse/pull/19959) ([PHO](https://github.com/depressed-pho)).
+* BloomFilter index crash fix. Fixes [#19757](https://github.com/ClickHouse/ClickHouse/issues/19757). [#19884](https://github.com/ClickHouse/ClickHouse/pull/19884) ([Maksim Kita](https://github.com/kitaisreal)).
+* Deadlock was possible if system.text_log is enabled. This fixes [#19874](https://github.com/ClickHouse/ClickHouse/issues/19874). [#19875](https://github.com/ClickHouse/ClickHouse/pull/19875) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix starting the server with tables having default expressions containing dictGet(). Allow getting return type of dictGet() without loading dictionary. [#19805](https://github.com/ClickHouse/ClickHouse/pull/19805) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix clickhouse-client abort exception while executing only `select`. [#19790](https://github.com/ClickHouse/ClickHouse/pull/19790) ([taiyang-li](https://github.com/taiyang-li)).
+* Fix a bug that moving pieces to destination table may failed in case of launching multiple clickhouse-copiers. [#19743](https://github.com/ClickHouse/ClickHouse/pull/19743) ([madianjun](https://github.com/mdianjun)).
+* Background thread which executes `ON CLUSTER` queries might hang waiting for dropped replicated table to do something. It's fixed. [#19684](https://github.com/ClickHouse/ClickHouse/pull/19684) ([yiguolei](https://github.com/yiguolei)).
+
+#### Build/Testing/Packaging Improvement
+
+* Allow to build ClickHouse with AVX-2 enabled globally. It gives slight performance benefits on modern CPUs. Not recommended for production and will not be supported as official build for now. [#20180](https://github.com/ClickHouse/ClickHouse/pull/20180) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix some of the issues found by Coverity. See [#19964](https://github.com/ClickHouse/ClickHouse/issues/19964). [#20010](https://github.com/ClickHouse/ClickHouse/pull/20010) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow to start up with modified binary under gdb. In previous version if you set up breakpoint in gdb before start, server will refuse to start up due to failed integrity check. [#21258](https://github.com/ClickHouse/ClickHouse/pull/21258) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add a test for different compression methods in Kafka. [#21111](https://github.com/ClickHouse/ClickHouse/pull/21111) ([filimonov](https://github.com/filimonov)).
+* Fixed port clash from test_storage_kerberized_hdfs test. [#19974](https://github.com/ClickHouse/ClickHouse/pull/19974) ([Ilya Yatsishin](https://github.com/qoega)).
+* Print `stdout` and `stderr` to log when failed to start docker in integration tests. Before this PR there was a very short error message in this case which didn't help to investigate the problems. [#20631](https://github.com/ClickHouse/ClickHouse/pull/20631) ([Vitaly Baranov](https://github.com/vitlibar)).
+
+
+## ClickHouse release 21.2
+
+### ClickHouse release v21.2.2.8-stable, 2021-02-07
+
+#### Backward Incompatible Change
+
+* Bitwise functions (`bitAnd`, `bitOr`, etc) are forbidden for floating point arguments. Now you have to do explicit cast to integer. [#19853](https://github.com/ClickHouse/ClickHouse/pull/19853) ([Azat Khuzhin](https://github.com/azat)).
+* Forbid `lcm`/`gcd` for floats. [#19532](https://github.com/ClickHouse/ClickHouse/pull/19532) ([Azat Khuzhin](https://github.com/azat)).
+* Fix memory tracking for `OPTIMIZE TABLE`/merges; account query memory limits and sampling for `OPTIMIZE TABLE`/merges. [#18772](https://github.com/ClickHouse/ClickHouse/pull/18772) ([Azat Khuzhin](https://github.com/azat)).
+* Disallow floating point column as partition key, see [#18421](https://github.com/ClickHouse/ClickHouse/issues/18421#event-4147046255). [#18464](https://github.com/ClickHouse/ClickHouse/pull/18464) ([hexiaoting](https://github.com/hexiaoting)).
+* Excessive parenthesis in type definitions no longer supported, example: `Array((UInt8))`.
+
+#### New Feature
+
+* Added `PostgreSQL` table engine (both select/insert, with support for multidimensional arrays), also as table function. Added `PostgreSQL` dictionary source. Added `PostgreSQL` database engine. [#18554](https://github.com/ClickHouse/ClickHouse/pull/18554) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Data type `Nested` now supports arbitrary levels of nesting. Introduced subcolumns of complex types, such as `size0` in `Array`, `null` in `Nullable`, names of `Tuple` elements, which can be read without reading of whole column. [#17310](https://github.com/ClickHouse/ClickHouse/pull/17310) ([Anton Popov](https://github.com/CurtizJ)).
+* Added `Nullable` support for `FlatDictionary`, `HashedDictionary`, `ComplexKeyHashedDictionary`, `DirectDictionary`, `ComplexKeyDirectDictionary`, `RangeHashedDictionary`. [#18236](https://github.com/ClickHouse/ClickHouse/pull/18236) ([Maksim Kita](https://github.com/kitaisreal)).
+* Adds a new table called `system.distributed_ddl_queue` that displays the queries in the DDL worker queue. [#17656](https://github.com/ClickHouse/ClickHouse/pull/17656) ([Bharat Nallan](https://github.com/bharatnc)).
+* Added support of mapping LDAP group names, and attribute values in general, to local roles for users from ldap user directories. [#17211](https://github.com/ClickHouse/ClickHouse/pull/17211) ([Denis Glazachev](https://github.com/traceon)).
+* Support insert into table function `cluster`, and for both table functions `remote` and `cluster`, support distributing data across nodes by specify sharding key. Close [#16752](https://github.com/ClickHouse/ClickHouse/issues/16752). [#18264](https://github.com/ClickHouse/ClickHouse/pull/18264) ([flynn](https://github.com/ucasFL)).
+* Add function `decodeXMLComponent` to decode characters for XML. Example: `SELECT decodeXMLComponent('Hello,&quot;world&quot;!')` [#17659](https://github.com/ClickHouse/ClickHouse/issues/17659). [#18542](https://github.com/ClickHouse/ClickHouse/pull/18542) ([nauta](https://github.com/nautaa)).
+* Added functions `parseDateTimeBestEffortUSOrZero`, `parseDateTimeBestEffortUSOrNull`. [#19712](https://github.com/ClickHouse/ClickHouse/pull/19712) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add `sign` math function. [#19527](https://github.com/ClickHouse/ClickHouse/pull/19527) ([flynn](https://github.com/ucasFL)).
+* Add information about used features (functions, table engines, etc) into system.query_log. [#18495](https://github.com/ClickHouse/ClickHouse/issues/18495). [#19371](https://github.com/ClickHouse/ClickHouse/pull/19371) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Function `formatDateTime` support the `%Q` modification to format date to quarter. [#19224](https://github.com/ClickHouse/ClickHouse/pull/19224) ([Jianmei Zhang](https://github.com/zhangjmruc)).
+* Support MetaKey+Enter hotkey binding in play UI. [#19012](https://github.com/ClickHouse/ClickHouse/pull/19012) ([sundyli](https://github.com/sundy-li)).
+* Add three functions for map data type: 1. `mapContains(map, key)` to check weather map.keys include the second parameter key. 2. `mapKeys(map)` return all the keys in Array format 3. `mapValues(map)` return all the values in Array format. [#18788](https://github.com/ClickHouse/ClickHouse/pull/18788) ([hexiaoting](https://github.com/hexiaoting)).
+* Add `log_comment` setting related to [#18494](https://github.com/ClickHouse/ClickHouse/issues/18494). [#18549](https://github.com/ClickHouse/ClickHouse/pull/18549) ([Zijie Lu](https://github.com/TszKitLo40)).
+* Add support of tuple argument to `argMin` and `argMax` functions. [#17359](https://github.com/ClickHouse/ClickHouse/pull/17359) ([Ildus Kurbangaliev](https://github.com/ildus)).
+* Support `EXISTS VIEW` syntax. [#18552](https://github.com/ClickHouse/ClickHouse/pull/18552) ([Du Chuan](https://github.com/spongedu)).
+* Add `SELECT ALL` syntax. closes [#18706](https://github.com/ClickHouse/ClickHouse/issues/18706). [#18723](https://github.com/ClickHouse/ClickHouse/pull/18723) ([flynn](https://github.com/ucasFL)).
+
+#### Performance Improvement
+
+* Faster parts removal by lowering the number of `stat` syscalls. This returns the optimization that existed while ago. More safe interface of `IDisk`. This closes [#19065](https://github.com/ClickHouse/ClickHouse/issues/19065). [#19086](https://github.com/ClickHouse/ClickHouse/pull/19086) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Aliases declared in `WITH` statement are properly used in index analysis. Queries like `WITH column AS alias SELECT ... WHERE alias = ...` may use index now. [#18896](https://github.com/ClickHouse/ClickHouse/pull/18896) ([Amos Bird](https://github.com/amosbird)).
+* Add `optimize_alias_column_prediction` (on by default), that will: - Respect aliased columns in WHERE during partition pruning and skipping data using secondary indexes; - Respect aliased columns in WHERE for trivial count queries for optimize_trivial_count; - Respect aliased columns in GROUP BY/ORDER BY for optimize_aggregation_in_order/optimize_read_in_order. [#16995](https://github.com/ClickHouse/ClickHouse/pull/16995) ([sundyli](https://github.com/sundy-li)).
+* Speed up aggregate function `sum`. Improvement only visible on synthetic benchmarks and not very practical. [#19216](https://github.com/ClickHouse/ClickHouse/pull/19216) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Update libc++ and use another ABI to provide better performance. [#18914](https://github.com/ClickHouse/ClickHouse/pull/18914) ([Danila Kutenin](https://github.com/danlark1)).
+* Rewrite `sumIf()` and `sum(if())` function to `countIf()` function when logically equivalent. [#17041](https://github.com/ClickHouse/ClickHouse/pull/17041) ([flynn](https://github.com/ucasFL)).
+* Use a connection pool for S3 connections, controlled by the `s3_max_connections` settings. [#13405](https://github.com/ClickHouse/ClickHouse/pull/13405) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Add support for zstd long option for better compression of string columns to save space. [#17184](https://github.com/ClickHouse/ClickHouse/pull/17184) ([ygrek](https://github.com/ygrek)).
+* Slightly improve server latency by removing access to configuration on every connection. [#19863](https://github.com/ClickHouse/ClickHouse/pull/19863) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Reduce lock contention for multiple layers of the `Buffer` engine. [#19379](https://github.com/ClickHouse/ClickHouse/pull/19379) ([Azat Khuzhin](https://github.com/azat)).
+* Support splitting `Filter` step of query plan into `Expression + Filter` pair. Together with `Expression + Expression` merging optimization ([#17458](https://github.com/ClickHouse/ClickHouse/issues/17458)) it may delay execution for some expressions after `Filter` step. [#19253](https://github.com/ClickHouse/ClickHouse/pull/19253) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+
+#### Improvement
+
+* `SELECT count() FROM table` now can be executed if only one any column can be selected from the `table`. This PR fixes [#10639](https://github.com/ClickHouse/ClickHouse/issues/10639). [#18233](https://github.com/ClickHouse/ClickHouse/pull/18233) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Set charset to `utf8mb4` when interacting with remote MySQL servers. Fixes [#19795](https://github.com/ClickHouse/ClickHouse/issues/19795). [#19800](https://github.com/ClickHouse/ClickHouse/pull/19800) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* `S3` table function now supports `auto` compression mode (autodetect). This closes [#18754](https://github.com/ClickHouse/ClickHouse/issues/18754). [#19793](https://github.com/ClickHouse/ClickHouse/pull/19793) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Correctly output infinite arguments for `formatReadableTimeDelta` function. In previous versions, there was implicit conversion to implementation specific integer value. [#19791](https://github.com/ClickHouse/ClickHouse/pull/19791) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Table function `S3` will use global region if the region can't be determined exactly. This closes [#10998](https://github.com/ClickHouse/ClickHouse/issues/10998). [#19750](https://github.com/ClickHouse/ClickHouse/pull/19750) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* In distributed queries if the setting `async_socket_for_remote` is enabled, it was possible to get stack overflow at least in debug build configuration if very deeply nested data type is used in table (e.g. `Array(Array(Array(...more...)))`). This fixes [#19108](https://github.com/ClickHouse/ClickHouse/issues/19108). This change introduces minor backward incompatibility: excessive parenthesis in type definitions no longer supported, example: `Array((UInt8))`. [#19736](https://github.com/ClickHouse/ClickHouse/pull/19736) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add separate pool for message brokers (RabbitMQ and Kafka). [#19722](https://github.com/ClickHouse/ClickHouse/pull/19722) ([Azat Khuzhin](https://github.com/azat)).
+* Fix rare `max_number_of_merges_with_ttl_in_pool` limit overrun (more merges with TTL can be assigned) for non-replicated MergeTree. [#19708](https://github.com/ClickHouse/ClickHouse/pull/19708) ([alesapin](https://github.com/alesapin)).
+* Dictionary: better error message during attribute parsing. [#19678](https://github.com/ClickHouse/ClickHouse/pull/19678) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add an option to disable validation of checksums on reading. Should never be used in production. Please do not expect any benefits in disabling it. It may only be used for experiments and benchmarks. The setting only applicable for tables of MergeTree family. Checksums are always validated for other table engines and when receiving data over network. In my observations there is no performance difference or it is less than 0.5%. [#19588](https://github.com/ClickHouse/ClickHouse/pull/19588) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support constant result in function `multiIf`. [#19533](https://github.com/ClickHouse/ClickHouse/pull/19533) ([Maksim Kita](https://github.com/kitaisreal)).
+* Enable function length/empty/notEmpty for datatype Map, which returns keys number in Map. [#19530](https://github.com/ClickHouse/ClickHouse/pull/19530) ([taiyang-li](https://github.com/taiyang-li)).
+* Add `--reconnect` option to `clickhouse-benchmark`. When this option is specified, it will reconnect before every request. This is needed for testing. [#19872](https://github.com/ClickHouse/ClickHouse/pull/19872) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support using the new location of `.debug` file. This fixes [#19348](https://github.com/ClickHouse/ClickHouse/issues/19348). [#19520](https://github.com/ClickHouse/ClickHouse/pull/19520) ([Amos Bird](https://github.com/amosbird)).
+* `toIPv6` function parses `IPv4` addresses. [#19518](https://github.com/ClickHouse/ClickHouse/pull/19518) ([Bharat Nallan](https://github.com/bharatnc)).
+* Add `http_referer` field to `system.query_log`, `system.processes`, etc. This closes [#19389](https://github.com/ClickHouse/ClickHouse/issues/19389). [#19390](https://github.com/ClickHouse/ClickHouse/pull/19390) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Improve MySQL compatibility by making more functions case insensitive and adding aliases. [#19387](https://github.com/ClickHouse/ClickHouse/pull/19387) ([Daniil Kondratyev](https://github.com/dankondr)).
+* Add metrics for MergeTree parts (Wide/Compact/InMemory) types. [#19381](https://github.com/ClickHouse/ClickHouse/pull/19381) ([Azat Khuzhin](https://github.com/azat)).
+* Allow docker to be executed with arbitrary uid. [#19374](https://github.com/ClickHouse/ClickHouse/pull/19374) ([filimonov](https://github.com/filimonov)).
+* Fix wrong alignment of values of `IPv4` data type in Pretty formats. They were aligned to the right, not to the left. This closes [#19184](https://github.com/ClickHouse/ClickHouse/issues/19184). [#19339](https://github.com/ClickHouse/ClickHouse/pull/19339) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow change `max_server_memory_usage` without restart. This closes [#18154](https://github.com/ClickHouse/ClickHouse/issues/18154). [#19186](https://github.com/ClickHouse/ClickHouse/pull/19186) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* The exception when function `bar` is called with certain NaN argument may be slightly misleading in previous versions. This fixes [#19088](https://github.com/ClickHouse/ClickHouse/issues/19088). [#19107](https://github.com/ClickHouse/ClickHouse/pull/19107) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Explicitly set uid / gid of clickhouse user & group to the fixed values (101) in clickhouse-server images. [#19096](https://github.com/ClickHouse/ClickHouse/pull/19096) ([filimonov](https://github.com/filimonov)).
+* Fixed `PeekableReadBuffer: Memory limit exceed` error when inserting data with huge strings. Fixes [#18690](https://github.com/ClickHouse/ClickHouse/issues/18690). [#18979](https://github.com/ClickHouse/ClickHouse/pull/18979) ([tavplubix](https://github.com/tavplubix)).
+* Docker image: several improvements for clickhouse-server entrypoint. [#18954](https://github.com/ClickHouse/ClickHouse/pull/18954) ([filimonov](https://github.com/filimonov)).
+* Add `normalizeQueryKeepNames` and `normalizedQueryHashKeepNames` to normalize queries without masking long names with `?`. This helps better analyze complex query logs. [#18910](https://github.com/ClickHouse/ClickHouse/pull/18910) ([Amos Bird](https://github.com/amosbird)).
+* Check per-block checksum of the distributed batch on the sender before sending (without reading the file twice, the checksums will be verified while reading), this will avoid stuck of the INSERT on the receiver (on truncated .bin file on the sender). Avoid reading .bin files twice for batched INSERT (it was required to calculate rows/bytes to take squashing into account, now this information included into the header, backward compatible is preserved). [#18853](https://github.com/ClickHouse/ClickHouse/pull/18853) ([Azat Khuzhin](https://github.com/azat)).
+* Fix issues with RIGHT and FULL JOIN of tables with aggregate function states. In previous versions exception about `cloneResized` method was thrown. [#18818](https://github.com/ClickHouse/ClickHouse/pull/18818) ([templarzq](https://github.com/templarzq)).
+* Added prefix-based S3 endpoint settings. [#18812](https://github.com/ClickHouse/ClickHouse/pull/18812) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Add [UInt8, UInt16, UInt32, UInt64] arguments types support for bitmapTransform, bitmapSubsetInRange, bitmapSubsetLimit, bitmapContains functions. This closes [#18713](https://github.com/ClickHouse/ClickHouse/issues/18713). [#18791](https://github.com/ClickHouse/ClickHouse/pull/18791) ([sundyli](https://github.com/sundy-li)).
+* Allow CTE (Common Table Expressions) to be further aliased. Propagate CSE (Common Subexpressions Elimination) to subqueries in the same level when `enable_global_with_statement = 1`. This fixes [#17378](https://github.com/ClickHouse/ClickHouse/issues/17378) . This fixes https://github.com/ClickHouse/ClickHouse/pull/16575#issuecomment-753416235 . [#18684](https://github.com/ClickHouse/ClickHouse/pull/18684) ([Amos Bird](https://github.com/amosbird)).
+* Update librdkafka to v1.6.0-RC2. Fixes [#18668](https://github.com/ClickHouse/ClickHouse/issues/18668). [#18671](https://github.com/ClickHouse/ClickHouse/pull/18671) ([filimonov](https://github.com/filimonov)).
+* In case of unexpected exceptions automatically restart background thread which is responsible for execution of distributed DDL queries. Fixes [#17991](https://github.com/ClickHouse/ClickHouse/issues/17991). [#18285](https://github.com/ClickHouse/ClickHouse/pull/18285) ([徐炘](https://github.com/weeds085490)).
+* Updated AWS C++ SDK in order to utilize global regions in S3. [#17870](https://github.com/ClickHouse/ClickHouse/pull/17870) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Added support for `WITH ... [AND] [PERIODIC] REFRESH [interval_in_sec]` clause when creating `LIVE VIEW` tables. [#14822](https://github.com/ClickHouse/ClickHouse/pull/14822) ([vzakaznikov](https://github.com/vzakaznikov)).
+* Restrict `MODIFY TTL` queries for `MergeTree` tables created in old syntax. Previously the query succeeded, but actually it had no effect. [#19064](https://github.com/ClickHouse/ClickHouse/pull/19064) ([Anton Popov](https://github.com/CurtizJ)).
+
+#### Bug Fix
+
+* Fix index analysis of binary functions with constant argument which leads to wrong query results. This fixes [#18364](https://github.com/ClickHouse/ClickHouse/issues/18364). [#18373](https://github.com/ClickHouse/ClickHouse/pull/18373) ([Amos Bird](https://github.com/amosbird)).
+* Fix starting the server with tables having default expressions containing dictGet(). Allow getting return type of dictGet() without loading dictionary. [#19805](https://github.com/ClickHouse/ClickHouse/pull/19805) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix server crash after query with `if` function with `Tuple` type of then/else branches result. `Tuple` type must contain `Array` or another complex type. Fixes [#18356](https://github.com/ClickHouse/ClickHouse/issues/18356). [#20133](https://github.com/ClickHouse/ClickHouse/pull/20133) ([alesapin](https://github.com/alesapin)).
+* `MaterializeMySQL` (experimental feature): Fix replication for statements that update several tables. [#20066](https://github.com/ClickHouse/ClickHouse/pull/20066) ([Håvard Kvålen](https://github.com/havardk)).
+* Prevent "Connection refused" in docker during initialization script execution. [#20012](https://github.com/ClickHouse/ClickHouse/pull/20012) ([filimonov](https://github.com/filimonov)).
+* `EmbeddedRocksDB` is an experimental storage. Fix the issue with lack of proper type checking. Simplified code. This closes [#19967](https://github.com/ClickHouse/ClickHouse/issues/19967). [#19972](https://github.com/ClickHouse/ClickHouse/pull/19972) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix a segfault in function `fromModifiedJulianDay` when the argument type is `Nullable(T)` for any integral types other than Int32. [#19959](https://github.com/ClickHouse/ClickHouse/pull/19959) ([PHO](https://github.com/depressed-pho)).
+* The function `greatCircleAngle` returned inaccurate results in previous versions. This closes [#19769](https://github.com/ClickHouse/ClickHouse/issues/19769). [#19789](https://github.com/ClickHouse/ClickHouse/pull/19789) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix rare bug when some replicated operations (like mutation) cannot process some parts after data corruption. Fixes [#19593](https://github.com/ClickHouse/ClickHouse/issues/19593). [#19702](https://github.com/ClickHouse/ClickHouse/pull/19702) ([alesapin](https://github.com/alesapin)).
+* Background thread which executes `ON CLUSTER` queries might hang waiting for dropped replicated table to do something. It's fixed. [#19684](https://github.com/ClickHouse/ClickHouse/pull/19684) ([yiguolei](https://github.com/yiguolei)).
+* Fix wrong deserialization of columns description. It makes INSERT into a table with a column named `\` impossible. [#19479](https://github.com/ClickHouse/ClickHouse/pull/19479) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Mark distributed batch as broken in case of empty data block in one of files. [#19449](https://github.com/ClickHouse/ClickHouse/pull/19449) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed very rare bug that might cause mutation to hang after `DROP/DETACH/REPLACE/MOVE PARTITION`. It was partially fixed by [#15537](https://github.com/ClickHouse/ClickHouse/issues/15537) for the most cases. [#19443](https://github.com/ClickHouse/ClickHouse/pull/19443) ([tavplubix](https://github.com/tavplubix)).
+* Fix possible error `Extremes transform was already added to pipeline`. Fixes [#14100](https://github.com/ClickHouse/ClickHouse/issues/14100). [#19430](https://github.com/ClickHouse/ClickHouse/pull/19430) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix default value in join types with non-zero default (e.g. some Enums). Closes [#18197](https://github.com/ClickHouse/ClickHouse/issues/18197). [#19360](https://github.com/ClickHouse/ClickHouse/pull/19360) ([vdimir](https://github.com/vdimir)).
+* Do not mark file for distributed send as broken on EOF. [#19290](https://github.com/ClickHouse/ClickHouse/pull/19290) ([Azat Khuzhin](https://github.com/azat)).
+* Fix leaking of pipe fd for `async_socket_for_remote`. [#19153](https://github.com/ClickHouse/ClickHouse/pull/19153) ([Azat Khuzhin](https://github.com/azat)).
+* Fix infinite reading from file in `ORC` format (was introduced in [#10580](https://github.com/ClickHouse/ClickHouse/issues/10580)). Fixes [#19095](https://github.com/ClickHouse/ClickHouse/issues/19095). [#19134](https://github.com/ClickHouse/ClickHouse/pull/19134) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix issue in merge tree data writer which can lead to marks with bigger size than fixed granularity size. Fixes [#18913](https://github.com/ClickHouse/ClickHouse/issues/18913). [#19123](https://github.com/ClickHouse/ClickHouse/pull/19123) ([alesapin](https://github.com/alesapin)).
+* Fix startup bug when clickhouse was not able to read compression codec from `LowCardinality(Nullable(...))` and throws exception `Attempt to read after EOF`. Fixes [#18340](https://github.com/ClickHouse/ClickHouse/issues/18340). [#19101](https://github.com/ClickHouse/ClickHouse/pull/19101) ([alesapin](https://github.com/alesapin)).
+* Simplify the implementation of `tupleHammingDistance`. Support for tuples of any equal length. Fixes [#19029](https://github.com/ClickHouse/ClickHouse/issues/19029). [#19084](https://github.com/ClickHouse/ClickHouse/pull/19084) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Make sure `groupUniqArray` returns correct type for argument of Enum type. This closes [#17875](https://github.com/ClickHouse/ClickHouse/issues/17875). [#19019](https://github.com/ClickHouse/ClickHouse/pull/19019) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible error `Expected single dictionary argument for function` if use function `ignore` with `LowCardinality` argument. Fixes [#14275](https://github.com/ClickHouse/ClickHouse/issues/14275). [#19016](https://github.com/ClickHouse/ClickHouse/pull/19016) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix inserting of `LowCardinality` column to table with `TinyLog` engine. Fixes [#18629](https://github.com/ClickHouse/ClickHouse/issues/18629). [#19010](https://github.com/ClickHouse/ClickHouse/pull/19010) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix minor issue in JOIN: Join tries to materialize const columns, but our code waits for them in other places. [#18982](https://github.com/ClickHouse/ClickHouse/pull/18982) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Disable `optimize_move_functions_out_of_any` because optimization is not always correct. This closes [#18051](https://github.com/ClickHouse/ClickHouse/issues/18051). This closes [#18973](https://github.com/ClickHouse/ClickHouse/issues/18973). [#18981](https://github.com/ClickHouse/ClickHouse/pull/18981) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible exception `QueryPipeline stream: different number of columns` caused by merging of query plan's `Expression` steps. Fixes [#18190](https://github.com/ClickHouse/ClickHouse/issues/18190). [#18980](https://github.com/ClickHouse/ClickHouse/pull/18980) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed very rare deadlock at shutdown. [#18977](https://github.com/ClickHouse/ClickHouse/pull/18977) ([tavplubix](https://github.com/tavplubix)).
+* Fixed rare crashes when server run out of memory. [#18976](https://github.com/ClickHouse/ClickHouse/pull/18976) ([tavplubix](https://github.com/tavplubix)).
+* Fix incorrect behavior when `ALTER TABLE ... DROP PART 'part_name'` query removes all deduplication blocks for the whole partition. Fixes [#18874](https://github.com/ClickHouse/ClickHouse/issues/18874). [#18969](https://github.com/ClickHouse/ClickHouse/pull/18969) ([alesapin](https://github.com/alesapin)).
+* Fixed issue [#18894](https://github.com/ClickHouse/ClickHouse/issues/18894) Add a check to avoid exception when long column alias('table.column' style, usually auto-generated by BI tools like Looker) equals to long table name. [#18968](https://github.com/ClickHouse/ClickHouse/pull/18968) ([Daniel Qin](https://github.com/mathfool)).
+* Fix error `Task was not found in task queue` (possible only for remote queries, with `async_socket_for_remote = 1`). [#18964](https://github.com/ClickHouse/ClickHouse/pull/18964) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug when mutation with some escaped text (like `ALTER ... UPDATE e = CAST('foo', 'Enum8(\'foo\' = 1')` serialized incorrectly. Fixes [#18878](https://github.com/ClickHouse/ClickHouse/issues/18878). [#18944](https://github.com/ClickHouse/ClickHouse/pull/18944) ([alesapin](https://github.com/alesapin)).
+* ATTACH PARTITION will reset mutations. [#18804](https://github.com/ClickHouse/ClickHouse/issues/18804). [#18935](https://github.com/ClickHouse/ClickHouse/pull/18935) ([fastio](https://github.com/fastio)).
+* Fix issue with `bitmapOrCardinality` that may lead to nullptr dereference. This closes [#18911](https://github.com/ClickHouse/ClickHouse/issues/18911). [#18912](https://github.com/ClickHouse/ClickHouse/pull/18912) ([sundyli](https://github.com/sundy-li)).
+* Fixed `Attempt to read after eof` error when trying to `CAST` `NULL` from `Nullable(String)` to `Nullable(Decimal(P, S))`. Now function `CAST` returns `NULL` when it cannot parse decimal from nullable string. Fixes [#7690](https://github.com/ClickHouse/ClickHouse/issues/7690). [#18718](https://github.com/ClickHouse/ClickHouse/pull/18718) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix data type convert issue for MySQL engine. [#18124](https://github.com/ClickHouse/ClickHouse/pull/18124) ([bo zeng](https://github.com/mis98zb)).
+* Fix clickhouse-client abort exception while executing only `select`. [#19790](https://github.com/ClickHouse/ClickHouse/pull/19790) ([taiyang-li](https://github.com/taiyang-li)).
+
+
+#### Build/Testing/Packaging Improvement
+
+* Run [SQLancer](https://twitter.com/RiggerManuel/status/1352345625480884228) (logical SQL fuzzer) in CI. [#19006](https://github.com/ClickHouse/ClickHouse/pull/19006) ([Ilya Yatsishin](https://github.com/qoega)).
+* Query Fuzzer will fuzz newly added tests more extensively. This closes [#18916](https://github.com/ClickHouse/ClickHouse/issues/18916). [#19185](https://github.com/ClickHouse/ClickHouse/pull/19185) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Integrate with [Big List of Naughty Strings](https://github.com/minimaxir/big-list-of-naughty-strings/) for better fuzzing. [#19480](https://github.com/ClickHouse/ClickHouse/pull/19480) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add integration tests run with MSan. [#18974](https://github.com/ClickHouse/ClickHouse/pull/18974) ([alesapin](https://github.com/alesapin)).
+* Fixed MemorySanitizer errors in cyrus-sasl and musl. [#19821](https://github.com/ClickHouse/ClickHouse/pull/19821) ([Ilya Yatsishin](https://github.com/qoega)).
+* Insuffiient arguments check in `positionCaseInsensitiveUTF8` function triggered address sanitizer. [#19720](https://github.com/ClickHouse/ClickHouse/pull/19720) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove --project-directory for docker-compose in integration test. Fix logs formatting from docker container. [#19706](https://github.com/ClickHouse/ClickHouse/pull/19706) ([Ilya Yatsishin](https://github.com/qoega)).
+* Made generation of macros.xml easier for integration tests. No more excessive logging from dicttoxml. dicttoxml project is not active for 5+ years. [#19697](https://github.com/ClickHouse/ClickHouse/pull/19697) ([Ilya Yatsishin](https://github.com/qoega)).
+* Allow to explicitly enable or disable watchdog via environment variable `CLICKHOUSE_WATCHDOG_ENABLE`. By default it is enabled if server is not attached to terminal. [#19522](https://github.com/ClickHouse/ClickHouse/pull/19522) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow building ClickHouse with Kafka support on arm64. [#19369](https://github.com/ClickHouse/ClickHouse/pull/19369) ([filimonov](https://github.com/filimonov)).
+* Allow building librdkafka without ssl. [#19337](https://github.com/ClickHouse/ClickHouse/pull/19337) ([filimonov](https://github.com/filimonov)).
+* Restore Kafka input in FreeBSD builds. [#18924](https://github.com/ClickHouse/ClickHouse/pull/18924) ([Alexandre Snarskii](https://github.com/snar)).
+* Fix potential nullptr dereference in table function `VALUES`. [#19357](https://github.com/ClickHouse/ClickHouse/pull/19357) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Avoid UBSan reports in `arrayElement` function, `substring` and `arraySum`. Fixes [#19305](https://github.com/ClickHouse/ClickHouse/issues/19305). Fixes [#19287](https://github.com/ClickHouse/ClickHouse/issues/19287). This closes [#19336](https://github.com/ClickHouse/ClickHouse/issues/19336). [#19347](https://github.com/ClickHouse/ClickHouse/pull/19347) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+
+## ClickHouse release 21.1
+
+### ClickHouse release v21.1.3.32-stable, 2021-02-03
+
+#### Bug Fix
+
+* BloomFilter index crash fix. Fixes [#19757](https://github.com/ClickHouse/ClickHouse/issues/19757). [#19884](https://github.com/ClickHouse/ClickHouse/pull/19884) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix crash when pushing down predicates to union distinct subquery. This fixes [#19855](https://github.com/ClickHouse/ClickHouse/issues/19855). [#19861](https://github.com/ClickHouse/ClickHouse/pull/19861) ([Amos Bird](https://github.com/amosbird)).
+* Fix filtering by UInt8 greater than 127. [#19799](https://github.com/ClickHouse/ClickHouse/pull/19799) ([Anton Popov](https://github.com/CurtizJ)).
+* In previous versions, unusual arguments for function arrayEnumerateUniq may cause crash or infinite loop. This closes [#19787](https://github.com/ClickHouse/ClickHouse/issues/19787). [#19788](https://github.com/ClickHouse/ClickHouse/pull/19788) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed stack overflow when using accurate comparison of arithmetic type with string type. [#19773](https://github.com/ClickHouse/ClickHouse/pull/19773) ([tavplubix](https://github.com/tavplubix)).
+* Fix crash when nested column name was used in `WHERE` or `PREWHERE`. Fixes [#19755](https://github.com/ClickHouse/ClickHouse/issues/19755). [#19763](https://github.com/ClickHouse/ClickHouse/pull/19763) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix a segmentation fault in `bitmapAndnot` function. Fixes [#19668](https://github.com/ClickHouse/ClickHouse/issues/19668). [#19713](https://github.com/ClickHouse/ClickHouse/pull/19713) ([Maksim Kita](https://github.com/kitaisreal)).
+* Some functions with big integers may cause segfault. Big integers is experimental feature. This closes [#19667](https://github.com/ClickHouse/ClickHouse/issues/19667). [#19672](https://github.com/ClickHouse/ClickHouse/pull/19672) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix wrong result of function `neighbor` for `LowCardinality` argument. Fixes [#10333](https://github.com/ClickHouse/ClickHouse/issues/10333). [#19617](https://github.com/ClickHouse/ClickHouse/pull/19617) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix use-after-free of the CompressedWriteBuffer in Connection after disconnect. [#19599](https://github.com/ClickHouse/ClickHouse/pull/19599) ([Azat Khuzhin](https://github.com/azat)).
+* `DROP/DETACH TABLE table ON CLUSTER cluster SYNC` query might hang, it's fixed. Fixes [#19568](https://github.com/ClickHouse/ClickHouse/issues/19568). [#19572](https://github.com/ClickHouse/ClickHouse/pull/19572) ([tavplubix](https://github.com/tavplubix)).
+* Query CREATE DICTIONARY id expression fix. [#19571](https://github.com/ClickHouse/ClickHouse/pull/19571) ([Maksim Kita](https://github.com/kitaisreal)).
+* Fix SIGSEGV with merge_tree_min_rows_for_concurrent_read/merge_tree_min_bytes_for_concurrent_read=0/UINT64_MAX. [#19528](https://github.com/ClickHouse/ClickHouse/pull/19528) ([Azat Khuzhin](https://github.com/azat)).
+* Buffer overflow (on memory read) was possible if `addMonth` function was called with specifically crafted arguments. This fixes [#19441](https://github.com/ClickHouse/ClickHouse/issues/19441). This fixes [#19413](https://github.com/ClickHouse/ClickHouse/issues/19413). [#19472](https://github.com/ClickHouse/ClickHouse/pull/19472) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Uninitialized memory read was possible in encrypt/decrypt functions if empty string was passed as IV. This closes [#19391](https://github.com/ClickHouse/ClickHouse/issues/19391). [#19397](https://github.com/ClickHouse/ClickHouse/pull/19397) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible buffer overflow in Uber H3 library. See https://github.com/uber/h3/issues/392. This closes [#19219](https://github.com/ClickHouse/ClickHouse/issues/19219). [#19383](https://github.com/ClickHouse/ClickHouse/pull/19383) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix system.parts _state column (LOGICAL_ERROR when querying this column, due to incorrect order). [#19346](https://github.com/ClickHouse/ClickHouse/pull/19346) ([Azat Khuzhin](https://github.com/azat)).
+* Fixed possible wrong result or segfault on aggregation when Materialized View and its target table have different structure. Fixes [#18063](https://github.com/ClickHouse/ClickHouse/issues/18063). [#19322](https://github.com/ClickHouse/ClickHouse/pull/19322) ([tavplubix](https://github.com/tavplubix)).
+* Fix error `Cannot convert column now64() because it is constant but values of constants are different in source and result`. Continuation of [#7156](https://github.com/ClickHouse/ClickHouse/issues/7156). [#19316](https://github.com/ClickHouse/ClickHouse/pull/19316) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug when concurrent `ALTER` and `DROP` queries may hang while processing ReplicatedMergeTree table. [#19237](https://github.com/ClickHouse/ClickHouse/pull/19237) ([alesapin](https://github.com/alesapin)).
+* Fixed `There is no checkpoint` error when inserting data through http interface using `Template` or `CustomSeparated` format. Fixes [#19021](https://github.com/ClickHouse/ClickHouse/issues/19021). [#19072](https://github.com/ClickHouse/ClickHouse/pull/19072) ([tavplubix](https://github.com/tavplubix)).
+* Disable constant folding for subqueries on the analysis stage, when the result cannot be calculated. [#18446](https://github.com/ClickHouse/ClickHouse/pull/18446) ([Azat Khuzhin](https://github.com/azat)).
+* Mutation might hang waiting for some non-existent part after `MOVE` or `REPLACE PARTITION` or, in rare cases, after `DETACH` or `DROP PARTITION`. It's fixed. [#15537](https://github.com/ClickHouse/ClickHouse/pull/15537) ([tavplubix](https://github.com/tavplubix)).
+
+
+
+### ClickHouse release v21.1.2.15-stable 2021-01-18
+
+#### Backward Incompatible Change
+
+* The setting `input_format_null_as_default` is enabled by default. [#17525](https://github.com/ClickHouse/ClickHouse/pull/17525) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Check settings constraints for profile settings from config. Server will fail to start if users.xml contain settings that do not meet corresponding constraints. [#18486](https://github.com/ClickHouse/ClickHouse/pull/18486) ([tavplubix](https://github.com/tavplubix)).
+* Restrict `ALTER MODIFY SETTING` from changing storage settings that affects data parts (`write_final_mark` and `enable_mixed_granularity_parts`). [#18306](https://github.com/ClickHouse/ClickHouse/pull/18306) ([Amos Bird](https://github.com/amosbird)).
+* Set `insert_quorum_parallel` to 1 by default. It is significantly more convenient to use than "sequential" quorum inserts. But if you rely to sequential consistency, you should set the setting back to zero. [#17567](https://github.com/ClickHouse/ClickHouse/pull/17567) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Remove `sumburConsistentHash` function. This closes [#18120](https://github.com/ClickHouse/ClickHouse/issues/18120). [#18656](https://github.com/ClickHouse/ClickHouse/pull/18656) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Removed aggregate functions `timeSeriesGroupSum`, `timeSeriesGroupRateSum` because a friend of mine said they never worked. This fixes [#16869](https://github.com/ClickHouse/ClickHouse/issues/16869). If you have luck using these functions, write a email to clickhouse-feedback@yandex-team.com. [#17423](https://github.com/ClickHouse/ClickHouse/pull/17423) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Prohibit toUnixTimestamp(Date()) (before it just returns UInt16 representation of Date). [#17376](https://github.com/ClickHouse/ClickHouse/pull/17376) ([Azat Khuzhin](https://github.com/azat)).
+* Allow using extended integer types (`Int128`, `Int256`, `UInt256`) in `avg` and `avgWeighted` functions. Also allow using different types (integer, decimal, floating point) for value and for weight in `avgWeighted` function. This is a backward-incompatible change: now the `avg` and `avgWeighted` functions always return `Float64` (as documented). Before this change the return type for `Decimal` arguments was also `Decimal`. [#15419](https://github.com/ClickHouse/ClickHouse/pull/15419) ([Mike](https://github.com/myrrc)).
+* Expression `toUUID(N)` no longer works. Replace with `toUUID('00000000-0000-0000-0000-000000000000')`. This change is motivated by non-obvious results of `toUUID(N)` where N is non zero.
+* SSL Certificates with incorrect "key usage" are rejected. In previous versions they are used to work. See [#19262](https://github.com/ClickHouse/ClickHouse/issues/19262).
+* `incl` references to substitutions file (`/etc/metrika.xml`) were removed from the default config (`<remote_servers>`, `<zookeeper>`, `<macros>`, `<compression>`, `<networks>`). If you were using substitutions file and were relying on those implicit references, you should put them back manually and explicitly by adding corresponding sections with `incl="..."` attributes before the update. See [#18740](https://github.com/ClickHouse/ClickHouse/pull/18740) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+
+#### New Feature
+
+* Implement gRPC protocol in ClickHouse. [#15111](https://github.com/ClickHouse/ClickHouse/pull/15111) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Allow to use multiple zookeeper clusters. [#17070](https://github.com/ClickHouse/ClickHouse/pull/17070) ([fastio](https://github.com/fastio)).
+* Implemented `REPLACE TABLE` and `CREATE OR REPLACE TABLE` queries. [#18521](https://github.com/ClickHouse/ClickHouse/pull/18521) ([tavplubix](https://github.com/tavplubix)).
+* Implement `UNION DISTINCT` and treat the plain `UNION` clause as `UNION DISTINCT` by default. Add a setting `union_default_mode` that allows to treat it as `UNION ALL` or require explicit mode specification. [#16338](https://github.com/ClickHouse/ClickHouse/pull/16338) ([flynn](https://github.com/ucasFL)).
+* Added function `accurateCastOrNull`. This closes [#10290](https://github.com/ClickHouse/ClickHouse/issues/10290). Add type conversions in `x IN (subquery)` expressions. This closes [#10266](https://github.com/ClickHouse/ClickHouse/issues/10266). [#16724](https://github.com/ClickHouse/ClickHouse/pull/16724) ([Maksim Kita](https://github.com/kitaisreal)).
+* IP Dictionary supports `IPv4` / `IPv6` types directly. [#17571](https://github.com/ClickHouse/ClickHouse/pull/17571) ([vdimir](https://github.com/vdimir)).
+* IP Dictionary supports key fetching. Resolves [#18241](https://github.com/ClickHouse/ClickHouse/issues/18241). [#18480](https://github.com/ClickHouse/ClickHouse/pull/18480) ([vdimir](https://github.com/vdimir)).
+* Add `*.zst` compression/decompression support for data import and export. It enables using `*.zst` in `file()` function and `Content-encoding: zstd` in HTTP client. This closes [#16791 ](https://github.com/ClickHouse/ClickHouse/issues/16791). [#17144](https://github.com/ClickHouse/ClickHouse/pull/17144) ([Abi Palagashvili](https://github.com/fibersel)).
+* Added `mannWitneyUTest`, `studentTTest` and `welchTTest` aggregate functions. Refactored `rankCorr` a bit. [#16883](https://github.com/ClickHouse/ClickHouse/pull/16883) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Add functions `countMatches`/`countMatchesCaseInsensitive`. [#17459](https://github.com/ClickHouse/ClickHouse/pull/17459) ([Azat Khuzhin](https://github.com/azat)).
+* Implement `countSubstrings()`/`countSubstringsCaseInsensitive()`/`countSubstringsCaseInsensitiveUTF8()` (Count the number of substring occurrences). [#17347](https://github.com/ClickHouse/ClickHouse/pull/17347) ([Azat Khuzhin](https://github.com/azat)).
+* Add information about used databases, tables and columns in system.query_log. Add `query_kind` and `normalized_query_hash` fields. [#17726](https://github.com/ClickHouse/ClickHouse/pull/17726) ([Amos Bird](https://github.com/amosbird)).
+* Add a setting `optimize_on_insert`. When enabled, do the same transformation for INSERTed block of data as if merge was done on this block (e.g. Replacing, Collapsing, Aggregating...). This setting is enabled by default. This can influence Materialized View and MaterializeMySQL behaviour (see detailed description). This closes [#10683](https://github.com/ClickHouse/ClickHouse/issues/10683). [#16954](https://github.com/ClickHouse/ClickHouse/pull/16954) ([Kruglov Pavel](https://github.com/Avogar)).
+* Kerberos Authenticaiton for HDFS. [#16621](https://github.com/ClickHouse/ClickHouse/pull/16621) ([Ilya Golshtein](https://github.com/ilejn)).
+* Support `SHOW SETTINGS` statement to show parameters in system.settings. `SHOW CHANGED SETTINGS` and `LIKE/ILIKE` clause are also supported. [#18056](https://github.com/ClickHouse/ClickHouse/pull/18056) ([Jianmei Zhang](https://github.com/zhangjmruc)).
+* Function `position` now supports `POSITION(needle IN haystack)` synax for SQL compatibility. This closes [#18701](https://github.com/ClickHouse/ClickHouse/issues/18701). ... [#18779](https://github.com/ClickHouse/ClickHouse/pull/18779) ([Jianmei Zhang](https://github.com/zhangjmruc)).
+* Now we have a new storage setting `max_partitions_to_read` for tables in the MergeTree family. It limits the max number of partitions that can be accessed in one query. A user setting `force_max_partition_limit` is also added to enforce this constraint. [#18712](https://github.com/ClickHouse/ClickHouse/pull/18712) ([Amos Bird](https://github.com/amosbird)).
+* Add `query_id` column to `system.part_log` for inserted parts. Closes [#10097](https://github.com/ClickHouse/ClickHouse/issues/10097). [#18644](https://github.com/ClickHouse/ClickHouse/pull/18644) ([flynn](https://github.com/ucasFL)).
+* Allow create table as select with columns specification. Example `CREATE TABLE t1 (x String) ENGINE = Memory AS SELECT 1;`. [#18060](https://github.com/ClickHouse/ClickHouse/pull/18060) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added `arrayMin`, `arrayMax`, `arrayAvg` aggregation functions. [#18032](https://github.com/ClickHouse/ClickHouse/pull/18032) ([Maksim Kita](https://github.com/kitaisreal)).
+* Implemented `ATTACH TABLE name FROM 'path/to/data/' (col1 Type1, ...` query. It creates new table with provided structure and attaches table data from provided directory in `user_files`. [#17903](https://github.com/ClickHouse/ClickHouse/pull/17903) ([tavplubix](https://github.com/tavplubix)).
+* Add mutation support for StorageMemory. This closes [#9117](https://github.com/ClickHouse/ClickHouse/issues/9117). [#15127](https://github.com/ClickHouse/ClickHouse/pull/15127) ([flynn](https://github.com/ucasFL)).
+* Support syntax `EXISTS DATABASE name`. [#18458](https://github.com/ClickHouse/ClickHouse/pull/18458) ([Du Chuan](https://github.com/spongedu)).
+* Support builtin function `isIPv4String` && `isIPv6String` like [MySQL](https://github.com/ClickHouse/ClickHouse/compare/master...spongedu:support_is_ipv4?expand=1). [#18349](https://github.com/ClickHouse/ClickHouse/pull/18349) ([Du Chuan](https://github.com/spongedu)).
+* Add a new setting `insert_distributed_one_random_shard = 1` to allow insertion into multi-sharded distributed table without any distributed key. [#18294](https://github.com/ClickHouse/ClickHouse/pull/18294) ([Amos Bird](https://github.com/amosbird)).
+* Add settings `min_compress_block_size` and `max_compress_block_size` to MergeTreeSettings, which have higher priority than the global settings and take effect when they are set. close [13890](https://github.com/ClickHouse/ClickHouse/issues/13890). [#17867](https://github.com/ClickHouse/ClickHouse/pull/17867) ([flynn](https://github.com/ucasFL)).
+* Add support for 64bit roaring bitmaps. [#17858](https://github.com/ClickHouse/ClickHouse/pull/17858) ([Andy Yang](https://github.com/andyyzh)).
+* Extended `OPTIMIZE ... DEDUPLICATE` syntax to allow explicit (or implicit with asterisk/column transformers) list of columns to check for duplicates on. ... [#17846](https://github.com/ClickHouse/ClickHouse/pull/17846) ([Vasily Nemkov](https://github.com/Enmk)).
+* Added functions `toModifiedJulianDay`, `fromModifiedJulianDay`, `toModifiedJulianDayOrNull`, and `fromModifiedJulianDayOrNull`. These functions convert between Proleptic Gregorian calendar date and Modified Julian Day number. [#17750](https://github.com/ClickHouse/ClickHouse/pull/17750) ([PHO](https://github.com/depressed-pho)).
+* Add ability to use custom TLD list: added functions `firstSignificantSubdomainCustom`, `cutToFirstSignificantSubdomainCustom`. [#17748](https://github.com/ClickHouse/ClickHouse/pull/17748) ([Azat Khuzhin](https://github.com/azat)).
+* Add support for `PROXYv1` protocol to wrap native TCP interface. Allow quotas to be keyed by proxy-forwarded IP address (applied for `PROXYv1` address and for `X-Forwarded-For` from HTTP interface). This is useful when you provide access to ClickHouse only via trusted proxy (e.g. CloudFlare) but want to account user resources by their original IP addresses. This fixes [#17268](https://github.com/ClickHouse/ClickHouse/issues/17268). [#17707](https://github.com/ClickHouse/ClickHouse/pull/17707) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now clickhouse-client supports opening `EDITOR` to edit commands. `Alt-Shift-E`. [#17665](https://github.com/ClickHouse/ClickHouse/pull/17665) ([Amos Bird](https://github.com/amosbird)).
+* Add function `encodeXMLComponent` to escape characters to place string into XML text node or attribute. [#17659](https://github.com/ClickHouse/ClickHouse/pull/17659) ([nauta](https://github.com/nautaa)).
+* Introduce `DETACH TABLE/VIEW ... PERMANENTLY` syntax, so that after restarting the table does not reappear back automatically on restart (only by explicit request). The table can still be attached back using the short syntax ATTACH TABLE. Implements [#5555](https://github.com/ClickHouse/ClickHouse/issues/5555). Fixes [#13850](https://github.com/ClickHouse/ClickHouse/issues/13850). [#17642](https://github.com/ClickHouse/ClickHouse/pull/17642) ([filimonov](https://github.com/filimonov)).
+* Add asynchronous metrics on total amount of rows, bytes and parts in MergeTree tables. This fix [#11714](https://github.com/ClickHouse/ClickHouse/issues/11714). [#17639](https://github.com/ClickHouse/ClickHouse/pull/17639) ([flynn](https://github.com/ucasFL)).
+* Add settings `limit` and `offset` for out-of-SQL pagination: [#16176](https://github.com/ClickHouse/ClickHouse/issues/16176) They are useful for building APIs. These two settings will affect SELECT query as if it is added like `select * from (your_original_select_query) t limit xxx offset xxx;`. [#17633](https://github.com/ClickHouse/ClickHouse/pull/17633) ([hexiaoting](https://github.com/hexiaoting)).
+* Provide a new aggregator combinator : `-SimpleState` to build `SimpleAggregateFunction` types via query. It's useful for defining MaterializedView of AggregatingMergeTree engine, and will benefit projections too. [#16853](https://github.com/ClickHouse/ClickHouse/pull/16853) ([Amos Bird](https://github.com/amosbird)).
+* Added `queries-file` parameter for `clickhouse-client` and `clickhouse-local`. [#15930](https://github.com/ClickHouse/ClickHouse/pull/15930) ([Maksim Kita](https://github.com/kitaisreal)).
+* Added `query` parameter for `clickhouse-benchmark`. [#17832](https://github.com/ClickHouse/ClickHouse/pull/17832) ([Maksim Kita](https://github.com/kitaisreal)).
+* `EXPLAIN AST` now support queries other then `SELECT`. [#18136](https://github.com/ClickHouse/ClickHouse/pull/18136) ([taiyang-li](https://github.com/taiyang-li)).
+
+
+#### Experimental Feature
+
+* Added functions for calculation of minHash and simHash of text n-grams and shingles. They are intended for semi-duplicate search. Also functions `bitHammingDistance` and `tupleHammingDistance` are added. [#7649](https://github.com/ClickHouse/ClickHouse/pull/7649) ([flynn](https://github.com/ucasFL)).
+* Add new data type `Map`. See [#1841](https://github.com/ClickHouse/ClickHouse/issues/1841). First version for Map only supports `String` type of key and value. [#15806](https://github.com/ClickHouse/ClickHouse/pull/15806) ([hexiaoting](https://github.com/hexiaoting)).
+* Implement alternative SQL parser based on ANTLR4 runtime and generated from EBNF grammar. [#11298](https://github.com/ClickHouse/ClickHouse/pull/11298) ([Ivan](https://github.com/abyss7)).
+
+
+#### Performance Improvement
+
+* New IP Dictionary implementation with lower memory consumption, improved performance for some cases, and fixed bugs. [#16804](https://github.com/ClickHouse/ClickHouse/pull/16804) ([vdimir](https://github.com/vdimir)).
+* Parallel formatting for data export. [#11617](https://github.com/ClickHouse/ClickHouse/pull/11617) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* LDAP integration: Added `verification_cooldown` parameter in LDAP server connection configuration to allow caching of successful "bind" attempts for configurable period of time. [#15988](https://github.com/ClickHouse/ClickHouse/pull/15988) ([Denis Glazachev](https://github.com/traceon)).
+* Add `--no-system-table` option for `clickhouse-local` to run without system tables. This avoids initialization of `DateLUT` that may take noticeable amount of time (tens of milliseconds) at startup. [#18899](https://github.com/ClickHouse/ClickHouse/pull/18899) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Replace `PODArray` with `PODArrayWithStackMemory` in `AggregateFunctionWindowFunnelData` to improve `windowFunnel` function performance. [#18817](https://github.com/ClickHouse/ClickHouse/pull/18817) ([flynn](https://github.com/ucasFL)).
+* Don't send empty blocks to shards on synchronous INSERT into Distributed table. This closes [#14571](https://github.com/ClickHouse/ClickHouse/issues/14571). [#18775](https://github.com/ClickHouse/ClickHouse/pull/18775) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Optimized read for StorageMemory. [#18052](https://github.com/ClickHouse/ClickHouse/pull/18052) ([Maksim Kita](https://github.com/kitaisreal)).
+* Using Dragonbox algorithm for float to string conversion instead of ryu. This improves performance of float to string conversion significantly. [#17831](https://github.com/ClickHouse/ClickHouse/pull/17831) ([Maksim Kita](https://github.com/kitaisreal)).
+* Speedup `IPv6CIDRToRange` implementation. [#17569](https://github.com/ClickHouse/ClickHouse/pull/17569) ([vdimir](https://github.com/vdimir)).
+* Add `remerge_sort_lowered_memory_bytes_ratio` setting (If memory usage after remerge does not reduced by this ratio, remerge will be disabled). [#17539](https://github.com/ClickHouse/ClickHouse/pull/17539) ([Azat Khuzhin](https://github.com/azat)).
+* Improve performance of AggregatingMergeTree with SimpleAggregateFunction(String) in PK. [#17109](https://github.com/ClickHouse/ClickHouse/pull/17109) ([Azat Khuzhin](https://github.com/azat)).
+* Now the `-If` combinator is devirtualized, and `count` is properly vectorized. It is for [this PR](https://github.com/ClickHouse/ClickHouse/pull/17041). [#17043](https://github.com/ClickHouse/ClickHouse/pull/17043) ([Amos Bird](https://github.com/amosbird)).
+* Fix performance of reading from `Merge` tables over huge number of `MergeTree` tables. Fixes [#7748](https://github.com/ClickHouse/ClickHouse/issues/7748). [#16988](https://github.com/ClickHouse/ClickHouse/pull/16988) ([Anton Popov](https://github.com/CurtizJ)).
+* Improved performance of function `repeat`. [#16937](https://github.com/ClickHouse/ClickHouse/pull/16937) ([satanson](https://github.com/satanson)).
+* Slightly improved performance of float parsing. [#16809](https://github.com/ClickHouse/ClickHouse/pull/16809) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add possibility to skip merged partitions for `OPTIMIZE TABLE ... FINAL`. [#15939](https://github.com/ClickHouse/ClickHouse/pull/15939) ([Kruglov Pavel](https://github.com/Avogar)).
+* Integrate with [fast_float from Daniel Lemire](https://github.com/lemire/fast_float) to parse floating point numbers. [#16787](https://github.com/ClickHouse/ClickHouse/pull/16787) ([Maksim Kita](https://github.com/kitaisreal)). It is not enabled, because performance its performance is still lower than rough float parser in ClickHouse.
+* Fix max_distributed_connections (affects `prefer_localhost_replica = 1` and `max_threads != max_distributed_connections`). [#17848](https://github.com/ClickHouse/ClickHouse/pull/17848) ([Azat Khuzhin](https://github.com/azat)).
+* Adaptive choice of single/multi part upload when sending data to S3. Single part upload is controlled by a new setting `max_single_part_upload_size`. [#17934](https://github.com/ClickHouse/ClickHouse/pull/17934) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Support for async tasks in `PipelineExecutor`. Initial support of async sockets for remote queries. [#17868](https://github.com/ClickHouse/ClickHouse/pull/17868) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Allow to use `optimize_move_to_prewhere` optimization with compact parts, when sizes of columns are unknown. [#17330](https://github.com/ClickHouse/ClickHouse/pull/17330) ([Anton Popov](https://github.com/CurtizJ)).
+
+
+#### Improvement
+
+* Avoid deadlock when executing INSERT SELECT into itself from a table with `TinyLog` or `Log` table engines. This closes [#6802](https://github.com/ClickHouse/ClickHouse/issues/6802). This closes [#18691](https://github.com/ClickHouse/ClickHouse/issues/18691). This closes [#16812](https://github.com/ClickHouse/ClickHouse/issues/16812). This closes [#14570](https://github.com/ClickHouse/ClickHouse/issues/14570). [#15260](https://github.com/ClickHouse/ClickHouse/pull/15260) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Support `SHOW CREATE VIEW name` syntax like [MySQL](https://dev.mysql.com/doc/refman/5.7/en/show-create-view.html). [#18095](https://github.com/ClickHouse/ClickHouse/pull/18095) ([Du Chuan](https://github.com/spongedu)).
+* All queries of type `Decimal * Float` or vice versa are allowed, including aggregate ones (e.g. `SELECT sum(decimal_field * 1.1)` or `SELECT dec_col * float_col`), the result type is Float32 or Float64. [#18145](https://github.com/ClickHouse/ClickHouse/pull/18145) ([Mike](https://github.com/myrrc)).
+* Improved minimal Web UI: add history; add sharing support; avoid race condition of different requests; add request in-flight and ready indicators; add favicon; detect Ctrl+Enter if textarea is not in focus. [#17293](https://github.com/ClickHouse/ClickHouse/pull/17293) [#17770](https://github.com/ClickHouse/ClickHouse/pull/17770) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* clickhouse-server didn't send `close` request to ZooKeeper server. [#16837](https://github.com/ClickHouse/ClickHouse/pull/16837) ([alesapin](https://github.com/alesapin)).
+* Avoid server abnormal termination in case of too low memory limits (`max_memory_usage = 1` / `max_untracked_memory = 1`). [#17453](https://github.com/ClickHouse/ClickHouse/pull/17453) ([Azat Khuzhin](https://github.com/azat)).
+* Fix non-deterministic result of `windowFunnel` function in case of same timestamp for different events. [#18884](https://github.com/ClickHouse/ClickHouse/pull/18884) ([Fuwang Hu](https://github.com/fuwhu)).
+* Docker: Explicitly set uid / gid of clickhouse user & group to the fixed values (101) in clickhouse-server Docker images. [#19096](https://github.com/ClickHouse/ClickHouse/pull/19096) ([filimonov](https://github.com/filimonov)).
+* Asynchronous INSERTs to `Distributed` tables: Two new settings (by analogy with MergeTree family) has been added: - `fsync_after_insert` - Do fsync for every inserted. Will decreases performance of inserts. - `fsync_directories` - Do fsync for temporary directory (that is used for async INSERT only) after all operations (writes, renames, etc.). [#18864](https://github.com/ClickHouse/ClickHouse/pull/18864) ([Azat Khuzhin](https://github.com/azat)).
+* `SYSTEM KILL` command started to work in Docker. This closes [#18847](https://github.com/ClickHouse/ClickHouse/issues/18847). [#18848](https://github.com/ClickHouse/ClickHouse/pull/18848) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Expand macros in the zk path when executing `FETCH PARTITION`. [#18839](https://github.com/ClickHouse/ClickHouse/pull/18839) ([fastio](https://github.com/fastio)).
+* Apply `ALTER TABLE <replicated_table> ON CLUSTER MODIFY SETTING ...` to all replicas. Because we don't replicate such alter commands. [#18789](https://github.com/ClickHouse/ClickHouse/pull/18789) ([Amos Bird](https://github.com/amosbird)).
+* Allow column transformer `EXCEPT` to accept a string as regular expression matcher. This resolves [#18685](https://github.com/ClickHouse/ClickHouse/issues/18685) . [#18699](https://github.com/ClickHouse/ClickHouse/pull/18699) ([Amos Bird](https://github.com/amosbird)).
+* Fix SimpleAggregateFunction in SummingMergeTree. Now it works like AggregateFunction. In previous versions values were summed together regardless to the aggregate function. This fixes [#18564](https://github.com/ClickHouse/ClickHouse/issues/18564) . [#8052](https://github.com/ClickHouse/ClickHouse/issues/8052). [#18637](https://github.com/ClickHouse/ClickHouse/pull/18637) ([Amos Bird](https://github.com/amosbird)). Another fix of using `SimpleAggregateFunction` in `SummingMergeTree`. This fixes [#18676](https://github.com/ClickHouse/ClickHouse/issues/18676) . [#18677](https://github.com/ClickHouse/ClickHouse/pull/18677) ([Amos Bird](https://github.com/amosbird)).
+* Fixed assertion error inside allocator in case when last argument of function bar is NaN. Now simple ClickHouse's exception is being thrown. This fixes [#17876](https://github.com/ClickHouse/ClickHouse/issues/17876). [#18520](https://github.com/ClickHouse/ClickHouse/pull/18520) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix usability issue: no newline after exception message in some tools. [#18444](https://github.com/ClickHouse/ClickHouse/pull/18444) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Add ability to modify primary and partition key column type from `LowCardinality(Type)` to `Type` and vice versa. Also add an ability to modify primary key column type from `EnumX ` to `IntX` type. Fixes [#5604](https://github.com/ClickHouse/ClickHouse/issues/5604). [#18362](https://github.com/ClickHouse/ClickHouse/pull/18362) ([alesapin](https://github.com/alesapin)).
+* Implement `untuple` field access. [#18133](https://github.com/ClickHouse/ClickHouse/issues/18133). [#18309](https://github.com/ClickHouse/ClickHouse/pull/18309) ([hexiaoting](https://github.com/hexiaoting)).
+* Allow to parse Array fields from CSV if it is represented as a string containing array that was serialized as nested CSV. Example: `"[""Hello"", ""world"", ""42"""" TV""]"` will parse as `['Hello', 'world', '42" TV']`. Allow to parse array in CSV in a string without enclosing braces. Example: `"'Hello', 'world', '42"" TV'"` will parse as `['Hello', 'world', '42" TV']`. [#18271](https://github.com/ClickHouse/ClickHouse/pull/18271) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Make better adaptive granularity calculation for merge tree wide parts. [#18223](https://github.com/ClickHouse/ClickHouse/pull/18223) ([alesapin](https://github.com/alesapin)).
+* Now `clickhouse install` could work on Mac. The problem was that there is no procfs on this platform. [#18201](https://github.com/ClickHouse/ClickHouse/pull/18201) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Better hints for `SHOW ...` query syntax. [#18183](https://github.com/ClickHouse/ClickHouse/pull/18183) ([Du Chuan](https://github.com/spongedu)).
+* Array aggregation `arrayMin`, `arrayMax`, `arraySum`, `arrayAvg` support for `Int128`, `Int256`, `UInt256`. [#18147](https://github.com/ClickHouse/ClickHouse/pull/18147) ([Maksim Kita](https://github.com/kitaisreal)).
+* Add `disk` to Set and Join storage settings. [#18112](https://github.com/ClickHouse/ClickHouse/pull/18112) ([Grigory Pervakov](https://github.com/GrigoryPervakov)).
+* Access control: Now table function `merge()` requires current user to have `SELECT` privilege on each table it receives data from. This PR fixes [#16964](https://github.com/ClickHouse/ClickHouse/issues/16964). [#18104](https://github.com/ClickHouse/ClickHouse/pull/18104) [#17983](https://github.com/ClickHouse/ClickHouse/pull/17983) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Temporary tables are visible in the system tables `system.tables` and `system.columns` now only in those session where they have been created. The internal database `_temporary_and_external_tables` is now hidden in those system tables; temporary tables are shown as tables with empty database with the `is_temporary` flag set instead. [#18014](https://github.com/ClickHouse/ClickHouse/pull/18014) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix clickhouse-client rendering issue when the size of terminal window changes. [#18009](https://github.com/ClickHouse/ClickHouse/pull/18009) ([Amos Bird](https://github.com/amosbird)).
+* Decrease log verbosity of the events when the client drops the connection from Warning to Information. [#18005](https://github.com/ClickHouse/ClickHouse/pull/18005) ([filimonov](https://github.com/filimonov)).
+* Forcibly removing empty or bad metadata files from filesystem for DiskS3. S3 is an experimental feature. [#17935](https://github.com/ClickHouse/ClickHouse/pull/17935) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Access control: `allow_introspection_functions=0` prohibits usage of introspection functions but doesn't prohibit giving grants for them anymore (the grantee will need to set `allow_introspection_functions=1` for himself to be able to use that grant). Similarly `allow_ddl=0` prohibits usage of DDL commands but doesn't prohibit giving grants for them anymore. [#17908](https://github.com/ClickHouse/ClickHouse/pull/17908) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Usability improvement: hints for column names. [#17112](https://github.com/ClickHouse/ClickHouse/issues/17112). [#17857](https://github.com/ClickHouse/ClickHouse/pull/17857) ([fastio](https://github.com/fastio)).
+* Add diagnostic information when two merge tables try to read each other's data. [#17854](https://github.com/ClickHouse/ClickHouse/pull/17854) ([徐炘](https://github.com/weeds085490)).
+* Let the possibility to override timeout value for running script using the ClickHouse docker image. [#17818](https://github.com/ClickHouse/ClickHouse/pull/17818) ([Guillaume Tassery](https://github.com/YiuRULE)).
+* Check system log tables' engine definition grammar to prevent some configuration errors. Notes that this grammar check is not semantical, that means such mistakes as non-existent columns / expression functions would be not found out util the table is created. [#17739](https://github.com/ClickHouse/ClickHouse/pull/17739) ([Du Chuan](https://github.com/spongedu)).
+* Removed exception throwing at `RabbitMQ` table initialization if there was no connection (it will be reconnecting in the background). [#17709](https://github.com/ClickHouse/ClickHouse/pull/17709) ([Kseniia Sumarokova](https://github.com/kssenii)).
+* Do not ignore server memory limits during Buffer flush. [#17646](https://github.com/ClickHouse/ClickHouse/pull/17646) ([Azat Khuzhin](https://github.com/azat)).
+* Switch to patched version of RocksDB (from ClickHouse-Extras) to fix use-after-free error. [#17643](https://github.com/ClickHouse/ClickHouse/pull/17643) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Added an offset to exception message for parallel parsing. This fixes [#17457](https://github.com/ClickHouse/ClickHouse/issues/17457). [#17641](https://github.com/ClickHouse/ClickHouse/pull/17641) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Don't throw "Too many parts" error in the middle of INSERT query. [#17566](https://github.com/ClickHouse/ClickHouse/pull/17566) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Allow query parameters in UPDATE statement of ALTER query. Fixes [#10976](https://github.com/ClickHouse/ClickHouse/issues/10976). [#17563](https://github.com/ClickHouse/ClickHouse/pull/17563) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Query obfuscator: avoid usage of some SQL keywords for identifier names. [#17526](https://github.com/ClickHouse/ClickHouse/pull/17526) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Export current max ddl entry executed by DDLWorker via server metric. It's useful to check if DDLWorker hangs somewhere. [#17464](https://github.com/ClickHouse/ClickHouse/pull/17464) ([Amos Bird](https://github.com/amosbird)).
+* Export asynchronous metrics of all servers current threads. It's useful to track down issues like [this](https://github.com/ClickHouse-Extras/poco/pull/28). [#17463](https://github.com/ClickHouse/ClickHouse/pull/17463) ([Amos Bird](https://github.com/amosbird)).
+* Include dynamic columns like MATERIALIZED / ALIAS for wildcard query when settings `asterisk_include_materialized_columns` and `asterisk_include_alias_columns` are turned on. [#17462](https://github.com/ClickHouse/ClickHouse/pull/17462) ([Ken Chen](https://github.com/chenziliang)).
+* Allow specifying [TTL](https://clickhouse.com/docs/en/engines/table-engines/mergetree-family/mergetree/#mergetree-table-ttl) to remove old entries from [system log tables](https://clickhouse.com/docs/en/operations/system-tables/), using the `<ttl>` attribute in `config.xml`. [#17438](https://github.com/ClickHouse/ClickHouse/pull/17438) ([Du Chuan](https://github.com/spongedu)).
+* Now queries coming to the server via MySQL and PostgreSQL protocols have distinctive interface types (which can be seen in the `interface` column of the table`system.query_log`): `4` for MySQL, and `5` for PostgreSQL, instead of formerly used `1` which is now used for the native protocol only. [#17437](https://github.com/ClickHouse/ClickHouse/pull/17437) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix parsing of SETTINGS clause of the `INSERT ... SELECT ... SETTINGS` query. [#17414](https://github.com/ClickHouse/ClickHouse/pull/17414) ([Azat Khuzhin](https://github.com/azat)).
+* Correctly account memory in RadixSort. [#17412](https://github.com/ClickHouse/ClickHouse/pull/17412) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Add eof check in `receiveHello` in server to prevent getting `Attempt to read after eof` exception. [#17365](https://github.com/ClickHouse/ClickHouse/pull/17365) ([Kruglov Pavel](https://github.com/Avogar)).
+* Avoid possible stack overflow in bigint conversion. Big integers are experimental. [#17269](https://github.com/ClickHouse/ClickHouse/pull/17269) ([flynn](https://github.com/ucasFL)).
+* Now `set` indices will work with `GLOBAL IN`. This fixes [#17232](https://github.com/ClickHouse/ClickHouse/issues/17232) , [#5576](https://github.com/ClickHouse/ClickHouse/issues/5576) . [#17253](https://github.com/ClickHouse/ClickHouse/pull/17253) ([Amos Bird](https://github.com/amosbird)).
+* Add limit for http redirects in request to S3 storage (`s3_max_redirects`). [#17220](https://github.com/ClickHouse/ClickHouse/pull/17220) ([ianton-ru](https://github.com/ianton-ru)).
+* When `-OrNull` combinator combined `-If`, `-Merge`, `-MergeState`, `-State` combinators, we should put `-OrNull` in front. [#16935](https://github.com/ClickHouse/ClickHouse/pull/16935) ([flynn](https://github.com/ucasFL)).
+* Support HTTP proxy and HTTPS S3 endpoint configuration. [#16861](https://github.com/ClickHouse/ClickHouse/pull/16861) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Added proper authentication using environment, `~/.aws` and `AssumeRole` for S3 client. [#16856](https://github.com/ClickHouse/ClickHouse/pull/16856) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Add more OpenTelemetry spans. Add an example of how to export the span data to Zipkin. [#16535](https://github.com/ClickHouse/ClickHouse/pull/16535) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Cache dictionaries: Completely eliminate callbacks and locks for acquiring them. Keys are not divided into "not found" and "expired", but stored in the same map during query. [#14958](https://github.com/ClickHouse/ClickHouse/pull/14958) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix never worked `fsync_part_directory`/`fsync_after_insert`/`in_memory_parts_insert_sync` (experimental feature). [#18845](https://github.com/ClickHouse/ClickHouse/pull/18845) ([Azat Khuzhin](https://github.com/azat)).
+* Allow using `Atomic` engine for nested database of `MaterializeMySQL` engine. [#14849](https://github.com/ClickHouse/ClickHouse/pull/14849) ([tavplubix](https://github.com/tavplubix)).
+
+
+#### Bug Fix
+
+* Fix the issue when server can stop accepting connections in very rare cases. [#17542](https://github.com/ClickHouse/ClickHouse/pull/17542) (Amos Bird, [alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix index analysis of binary functions with constant argument which leads to wrong query results. This fixes [#18364](https://github.com/ClickHouse/ClickHouse/issues/18364). [#18373](https://github.com/ClickHouse/ClickHouse/pull/18373) ([Amos Bird](https://github.com/amosbird)).
+* Fix possible wrong index analysis when the types of the index comparison are different. This fixes [#17122](https://github.com/ClickHouse/ClickHouse/issues/17122). [#17145](https://github.com/ClickHouse/ClickHouse/pull/17145) ([Amos Bird](https://github.com/amosbird)).
+* Disable write with AIO during merges because it can lead to extremely rare data corruption of primary key columns during merge. [#18481](https://github.com/ClickHouse/ClickHouse/pull/18481) ([alesapin](https://github.com/alesapin)).
+* Restrict merges from wide to compact parts. In case of vertical merge it led to broken result part. [#18381](https://github.com/ClickHouse/ClickHouse/pull/18381) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix possible incomplete query result while reading from `MergeTree*` in case of read backoff (message `<Debug> MergeTreeReadPool: Will lower number of threads` in logs). Was introduced in [#16423](https://github.com/ClickHouse/ClickHouse/issues/16423). Fixes [#18137](https://github.com/ClickHouse/ClickHouse/issues/18137). [#18216](https://github.com/ClickHouse/ClickHouse/pull/18216) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix use after free bug in `rocksdb` library. [#18862](https://github.com/ClickHouse/ClickHouse/pull/18862) ([sundyli](https://github.com/sundy-li)).
+* Fix infinite reading from file in `ORC` format (was introduced in [#10580](https://github.com/ClickHouse/ClickHouse/issues/10580)). Fixes [#19095](https://github.com/ClickHouse/ClickHouse/issues/19095). [#19134](https://github.com/ClickHouse/ClickHouse/pull/19134) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug in merge tree data writer which can lead to marks with bigger size than fixed granularity size. Fixes [#18913](https://github.com/ClickHouse/ClickHouse/issues/18913). [#19123](https://github.com/ClickHouse/ClickHouse/pull/19123) ([alesapin](https://github.com/alesapin)).
+* Fix startup bug when clickhouse was not able to read compression codec from `LowCardinality(Nullable(...))` and throws exception `Attempt to read after EOF`. Fixes [#18340](https://github.com/ClickHouse/ClickHouse/issues/18340). [#19101](https://github.com/ClickHouse/ClickHouse/pull/19101) ([alesapin](https://github.com/alesapin)).
+* Restrict `MODIFY TTL` queries for `MergeTree` tables created in old syntax. Previously the query succeeded, but actually it had no effect. [#19064](https://github.com/ClickHouse/ClickHouse/pull/19064) ([Anton Popov](https://github.com/CurtizJ)).
+* Make sure `groupUniqArray` returns correct type for argument of Enum type. This closes [#17875](https://github.com/ClickHouse/ClickHouse/issues/17875). [#19019](https://github.com/ClickHouse/ClickHouse/pull/19019) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible error `Expected single dictionary argument for function` if use function `ignore` with `LowCardinality` argument. Fixes [#14275](https://github.com/ClickHouse/ClickHouse/issues/14275). [#19016](https://github.com/ClickHouse/ClickHouse/pull/19016) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix inserting of `LowCardinality` column to table with `TinyLog` engine. Fixes [#18629](https://github.com/ClickHouse/ClickHouse/issues/18629). [#19010](https://github.com/ClickHouse/ClickHouse/pull/19010) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Join tries to materialize const columns, but our code wants them in other places. [#18982](https://github.com/ClickHouse/ClickHouse/pull/18982) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Disable `optimize_move_functions_out_of_any` because optimization is not always correct. This closes [#18051](https://github.com/ClickHouse/ClickHouse/issues/18051). This closes [#18973](https://github.com/ClickHouse/ClickHouse/issues/18973). [#18981](https://github.com/ClickHouse/ClickHouse/pull/18981) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix possible exception `QueryPipeline stream: different number of columns` caused by merging of query plan's `Expression` steps. Fixes [#18190](https://github.com/ClickHouse/ClickHouse/issues/18190). [#18980](https://github.com/ClickHouse/ClickHouse/pull/18980) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed very rare deadlock at shutdown. [#18977](https://github.com/ClickHouse/ClickHouse/pull/18977) ([tavplubix](https://github.com/tavplubix)).
+* Fix incorrect behavior when `ALTER TABLE ... DROP PART 'part_name'` query removes all deduplication blocks for the whole partition. Fixes [#18874](https://github.com/ClickHouse/ClickHouse/issues/18874). [#18969](https://github.com/ClickHouse/ClickHouse/pull/18969) ([alesapin](https://github.com/alesapin)).
+* Attach partition should reset the mutation. [#18804](https://github.com/ClickHouse/ClickHouse/issues/18804). [#18935](https://github.com/ClickHouse/ClickHouse/pull/18935) ([fastio](https://github.com/fastio)).
+* Fix issue with `bitmapOrCardinality` that may lead to nullptr dereference. This closes [#18911](https://github.com/ClickHouse/ClickHouse/issues/18911). [#18912](https://github.com/ClickHouse/ClickHouse/pull/18912) ([sundyli](https://github.com/sundy-li)).
+* Fix possible hang at shutdown in `clickhouse-local`. This fixes [#18891](https://github.com/ClickHouse/ClickHouse/issues/18891). [#18893](https://github.com/ClickHouse/ClickHouse/pull/18893) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Queries for external databases (MySQL, ODBC, JDBC) were incorrectly rewritten if there was an expression in form of `x IN table`. This fixes [#9756](https://github.com/ClickHouse/ClickHouse/issues/9756). [#18876](https://github.com/ClickHouse/ClickHouse/pull/18876) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix *If combinator with unary function and Nullable types. [#18806](https://github.com/ClickHouse/ClickHouse/pull/18806) ([Azat Khuzhin](https://github.com/azat)).
+* Fix the issue that asynchronous distributed INSERTs can be rejected by the server if the setting `network_compression_method` is globally set to non-default value. This fixes [#18741](https://github.com/ClickHouse/ClickHouse/issues/18741). [#18776](https://github.com/ClickHouse/ClickHouse/pull/18776) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed `Attempt to read after eof` error when trying to `CAST` `NULL` from `Nullable(String)` to `Nullable(Decimal(P, S))`. Now function `CAST` returns `NULL` when it cannot parse decimal from nullable string. Fixes [#7690](https://github.com/ClickHouse/ClickHouse/issues/7690). [#18718](https://github.com/ClickHouse/ClickHouse/pull/18718) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix minor issue with logging. [#18717](https://github.com/ClickHouse/ClickHouse/pull/18717) ([sundyli](https://github.com/sundy-li)).
+* Fix removing of empty parts in `ReplicatedMergeTree` tables, created with old syntax. Fixes [#18582](https://github.com/ClickHouse/ClickHouse/issues/18582). [#18614](https://github.com/ClickHouse/ClickHouse/pull/18614) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix previous bug when date overflow with different values. Strict Date value limit to "2106-02-07", cast date > "2106-02-07" to value 0. [#18565](https://github.com/ClickHouse/ClickHouse/pull/18565) ([hexiaoting](https://github.com/hexiaoting)).
+* Add FixedString data type support for replication from MySQL. Replication from MySQL is an experimental feature. This patch fixes [#18450](https://github.com/ClickHouse/ClickHouse/issues/18450) Also fixes [#6556](https://github.com/ClickHouse/ClickHouse/issues/6556). [#18553](https://github.com/ClickHouse/ClickHouse/pull/18553) ([awesomeleo](https://github.com/awesomeleo)).
+* Fix possible `Pipeline stuck` error while using `ORDER BY` after subquery with `RIGHT` or `FULL` join. [#18550](https://github.com/ClickHouse/ClickHouse/pull/18550) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fix bug which may lead to `ALTER` queries hung after corresponding mutation kill. Found by thread fuzzer. [#18518](https://github.com/ClickHouse/ClickHouse/pull/18518) ([alesapin](https://github.com/alesapin)).
+* Proper support for 12AM in `parseDateTimeBestEffort` function. This fixes [#18402](https://github.com/ClickHouse/ClickHouse/issues/18402). [#18449](https://github.com/ClickHouse/ClickHouse/pull/18449) ([vladimir-golovchenko](https://github.com/vladimir-golovchenko)).
+* Fixed `value is too short` error when executing `toType(...)` functions (`toDate`, `toUInt32`, etc) with argument of type `Nullable(String)`. Now such functions return `NULL` on parsing errors instead of throwing exception. Fixes [#7673](https://github.com/ClickHouse/ClickHouse/issues/7673). [#18445](https://github.com/ClickHouse/ClickHouse/pull/18445) ([tavplubix](https://github.com/tavplubix)).
+* Fix the unexpected behaviour of `SHOW TABLES`. [#18431](https://github.com/ClickHouse/ClickHouse/pull/18431) ([fastio](https://github.com/fastio)).
+* Fix -SimpleState combinator generates incompatible arugment type and return type. [#18404](https://github.com/ClickHouse/ClickHouse/pull/18404) ([Amos Bird](https://github.com/amosbird)).
+* Fix possible race condition in concurrent usage of `Set` or `Join` tables and selects from `system.tables`. [#18385](https://github.com/ClickHouse/ClickHouse/pull/18385) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix filling table `system.settings_profile_elements`. This PR fixes [#18231](https://github.com/ClickHouse/ClickHouse/issues/18231). [#18379](https://github.com/ClickHouse/ClickHouse/pull/18379) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix possible crashes in aggregate functions with combinator `Distinct`, while using two-level aggregation. Fixes [#17682](https://github.com/ClickHouse/ClickHouse/issues/17682). [#18365](https://github.com/ClickHouse/ClickHouse/pull/18365) ([Anton Popov](https://github.com/CurtizJ)).
+* Fixed issue when `clickhouse-odbc-bridge` process is unreachable by server on machines with dual IPv4/IPv6 stack; Fixed issue when ODBC dictionary updates are performed using malformed queries and/or cause crashes of the odbc-bridge process; Possibly closes [#14489](https://github.com/ClickHouse/ClickHouse/issues/14489). [#18278](https://github.com/ClickHouse/ClickHouse/pull/18278) ([Denis Glazachev](https://github.com/traceon)).
+* Access control: `SELECT count() FROM table` now can be executed if the user has access to at least single column from a table. This PR fixes [#10639](https://github.com/ClickHouse/ClickHouse/issues/10639). [#18233](https://github.com/ClickHouse/ClickHouse/pull/18233) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Access control: `SELECT JOIN` now requires the `SELECT` privilege on each of the joined tables. This PR fixes [#17654](https://github.com/ClickHouse/ClickHouse/issues/17654). [#18232](https://github.com/ClickHouse/ClickHouse/pull/18232) ([Vitaly Baranov](https://github.com/vitlibar)).
+* Fix key comparison between Enum and Int types. This fixes [#17989](https://github.com/ClickHouse/ClickHouse/issues/17989). [#18214](https://github.com/ClickHouse/ClickHouse/pull/18214) ([Amos Bird](https://github.com/amosbird)).
+* Replication from MySQL (experimental feature). Fixes [#18186](https://github.com/ClickHouse/ClickHouse/issues/18186) Fixes [#16372](https://github.com/ClickHouse/ClickHouse/issues/16372) Fix unique key convert issue in MaterializeMySQL database engine. [#18211](https://github.com/ClickHouse/ClickHouse/pull/18211) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix inconsistency for queries with both `WITH FILL` and `WITH TIES` [#17466](https://github.com/ClickHouse/ClickHouse/issues/17466). [#18188](https://github.com/ClickHouse/ClickHouse/pull/18188) ([hexiaoting](https://github.com/hexiaoting)).
+* Fix inserting a row with default value in case of parsing error in the last column. Fixes [#17712](https://github.com/ClickHouse/ClickHouse/issues/17712). [#18182](https://github.com/ClickHouse/ClickHouse/pull/18182) ([Jianmei Zhang](https://github.com/zhangjmruc)).
+* Fix `Unknown setting profile` error on attempt to set settings profile. [#18167](https://github.com/ClickHouse/ClickHouse/pull/18167) ([tavplubix](https://github.com/tavplubix)).
+* Fix error when query `MODIFY COLUMN ... REMOVE TTL` doesn't actually remove column TTL. [#18130](https://github.com/ClickHouse/ClickHouse/pull/18130) ([alesapin](https://github.com/alesapin)).
+* Fixed `std::out_of_range: basic_string` in S3 URL parsing. [#18059](https://github.com/ClickHouse/ClickHouse/pull/18059) ([Vladimir Chebotarev](https://github.com/excitoon)).
+* Fix comparison of `DateTime64` and `Date`. Fixes [#13804](https://github.com/ClickHouse/ClickHouse/issues/13804) and [#11222](https://github.com/ClickHouse/ClickHouse/issues/11222). ... [#18050](https://github.com/ClickHouse/ClickHouse/pull/18050) ([Vasily Nemkov](https://github.com/Enmk)).
+* Replication from MySQL (experimental feature): Fixes [#15187](https://github.com/ClickHouse/ClickHouse/issues/15187) Fixes [#17912](https://github.com/ClickHouse/ClickHouse/issues/17912) support convert MySQL prefix index for MaterializeMySQL. [#17944](https://github.com/ClickHouse/ClickHouse/pull/17944) ([Winter Zhang](https://github.com/zhang2014)).
+* When server log rotation was configured using `logger.size` parameter with numeric value larger than 2^32, the logs were not rotated properly. This is fixed. [#17905](https://github.com/ClickHouse/ClickHouse/pull/17905) ([Alexander Kuzmenkov](https://github.com/akuzm)).
+* Trivial query optimization was producing wrong result if query contains ARRAY JOIN (so query is actually non trivial). [#17887](https://github.com/ClickHouse/ClickHouse/pull/17887) ([sundyli](https://github.com/sundy-li)).
+* Fix possible segfault in `topK` aggregate function. This closes [#17404](https://github.com/ClickHouse/ClickHouse/issues/17404). [#17845](https://github.com/ClickHouse/ClickHouse/pull/17845) ([Maksim Kita](https://github.com/kitaisreal)).
+* WAL (experimental feature): Do not restore parts from WAL if `in_memory_parts_enable_wal` is disabled. [#17802](https://github.com/ClickHouse/ClickHouse/pull/17802) ([detailyang](https://github.com/detailyang)).
+* Exception message about max table size to drop was displayed incorrectly. [#17764](https://github.com/ClickHouse/ClickHouse/pull/17764) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fixed possible segfault when there is not enough space when inserting into `Distributed` table. [#17737](https://github.com/ClickHouse/ClickHouse/pull/17737) ([tavplubix](https://github.com/tavplubix)).
+* Fixed problem when ClickHouse fails to resume connection to MySQL servers. [#17681](https://github.com/ClickHouse/ClickHouse/pull/17681) ([Alexander Kazakov](https://github.com/Akazz)).
+* Windows: Fixed `Function not implemented` error when executing `RENAME` query in `Atomic` database with ClickHouse running on Windows Subsystem for Linux. Fixes [#17661](https://github.com/ClickHouse/ClickHouse/issues/17661). [#17664](https://github.com/ClickHouse/ClickHouse/pull/17664) ([tavplubix](https://github.com/tavplubix)).
+* In might be determined incorrectly if cluster is circular- (cross-) replicated or not when executing `ON CLUSTER` query due to race condition when `pool_size` > 1. It's fixed. [#17640](https://github.com/ClickHouse/ClickHouse/pull/17640) ([tavplubix](https://github.com/tavplubix)).
+* Fix empty `system.stack_trace` table when server is running in daemon mode. [#17630](https://github.com/ClickHouse/ClickHouse/pull/17630) ([Amos Bird](https://github.com/amosbird)).
+* Exception `fmt::v7::format_error` can be logged in background for MergeTree tables. This fixes [#17613](https://github.com/ClickHouse/ClickHouse/issues/17613). [#17615](https://github.com/ClickHouse/ClickHouse/pull/17615) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* When clickhouse-client is used in interactive mode with multiline queries, single line comment was erronously extended till the end of query. This fixes [#13654](https://github.com/ClickHouse/ClickHouse/issues/13654). [#17565](https://github.com/ClickHouse/ClickHouse/pull/17565) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix alter query hang when the corresponding mutation was killed on the different replica. Fixes [#16953](https://github.com/ClickHouse/ClickHouse/issues/16953). [#17499](https://github.com/ClickHouse/ClickHouse/pull/17499) ([alesapin](https://github.com/alesapin)).
+* Fix issue with memory accounting when mark cache size was underestimated by clickhouse. It may happen when there are a lot of tiny files with marks. [#17496](https://github.com/ClickHouse/ClickHouse/pull/17496) ([alesapin](https://github.com/alesapin)).
+* Fix `ORDER BY` with enabled setting `optimize_redundant_functions_in_order_by`. [#17471](https://github.com/ClickHouse/ClickHouse/pull/17471) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix duplicates after `DISTINCT` which were possible because of incorrect optimization. Fixes [#17294](https://github.com/ClickHouse/ClickHouse/issues/17294). [#17296](https://github.com/ClickHouse/ClickHouse/pull/17296) ([li chengxiang](https://github.com/chengxianglibra)). [#17439](https://github.com/ClickHouse/ClickHouse/pull/17439) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Fixed high CPU usage in background tasks of *MergeTree tables. [#17416](https://github.com/ClickHouse/ClickHouse/pull/17416) ([tavplubix](https://github.com/tavplubix)).
+* Fix possible crash while reading from `JOIN` table with `LowCardinality` types. Fixes [#17228](https://github.com/ClickHouse/ClickHouse/issues/17228). [#17397](https://github.com/ClickHouse/ClickHouse/pull/17397) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
+* Replication from MySQL (experimental feature): Fixes [#16835](https://github.com/ClickHouse/ClickHouse/issues/16835) try fix miss match header with MySQL SHOW statement. [#17366](https://github.com/ClickHouse/ClickHouse/pull/17366) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix nondeterministic functions with predicate optimizer. This fixes [#17244](https://github.com/ClickHouse/ClickHouse/issues/17244). [#17273](https://github.com/ClickHouse/ClickHouse/pull/17273) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix possible `Unexpected packet Data received from client` error for Distributed queries with `LIMIT`. [#17254](https://github.com/ClickHouse/ClickHouse/pull/17254) ([Azat Khuzhin](https://github.com/azat)).
+* Fix set index invalidation when there are const columns in the subquery. This fixes [#17246](https://github.com/ClickHouse/ClickHouse/issues/17246). [#17249](https://github.com/ClickHouse/ClickHouse/pull/17249) ([Amos Bird](https://github.com/amosbird)).
+* clickhouse-copier: Fix for non-partitioned tables [#15235](https://github.com/ClickHouse/ClickHouse/issues/15235). [#17248](https://github.com/ClickHouse/ClickHouse/pull/17248) ([Qi Chen](https://github.com/kaka11chen)).
+* Fixed possible not-working mutations for parts stored on S3 disk (experimental feature). [#17227](https://github.com/ClickHouse/ClickHouse/pull/17227) ([Pavel Kovalenko](https://github.com/Jokser)).
+* Bug fix for funciton `fuzzBits`, related issue: [#16980](https://github.com/ClickHouse/ClickHouse/issues/16980). [#17051](https://github.com/ClickHouse/ClickHouse/pull/17051) ([hexiaoting](https://github.com/hexiaoting)).
+* Fix `optimize_distributed_group_by_sharding_key` for query with OFFSET only. [#16996](https://github.com/ClickHouse/ClickHouse/pull/16996) ([Azat Khuzhin](https://github.com/azat)).
+* Fix queries from `Merge` tables over `Distributed` tables with JOINs. [#16993](https://github.com/ClickHouse/ClickHouse/pull/16993) ([Azat Khuzhin](https://github.com/azat)).
+* Fix order by optimization with monotonic functions. Fixes [#16107](https://github.com/ClickHouse/ClickHouse/issues/16107). [#16956](https://github.com/ClickHouse/ClickHouse/pull/16956) ([Anton Popov](https://github.com/CurtizJ)).
+* Fix incorrect comparison of types `DateTime64` with different scales. Fixes [#16655](https://github.com/ClickHouse/ClickHouse/issues/16655) ... [#16952](https://github.com/ClickHouse/ClickHouse/pull/16952) ([Vasily Nemkov](https://github.com/Enmk)).
+* Fix optimization of group by with enabled setting `optimize_aggregators_of_group_by_keys` and joins. Fixes [#12604](https://github.com/ClickHouse/ClickHouse/issues/12604). [#16951](https://github.com/ClickHouse/ClickHouse/pull/16951) ([Anton Popov](https://github.com/CurtizJ)).
+* Minor fix in SHOW ACCESS query. [#16866](https://github.com/ClickHouse/ClickHouse/pull/16866) ([tavplubix](https://github.com/tavplubix)).
+* Fix the behaviour with enabled `optimize_trivial_count_query` setting with partition predicate. [#16767](https://github.com/ClickHouse/ClickHouse/pull/16767) ([Azat Khuzhin](https://github.com/azat)).
+* Return number of affected rows for INSERT queries via MySQL wire protocol. Previously ClickHouse used to always return 0, it's fixed. Fixes [#16605](https://github.com/ClickHouse/ClickHouse/issues/16605). [#16715](https://github.com/ClickHouse/ClickHouse/pull/16715) ([Winter Zhang](https://github.com/zhang2014)).
+* Fix inconsistent behavior caused by `select_sequential_consistency` for optimized trivial count query and system tables. [#16309](https://github.com/ClickHouse/ClickHouse/pull/16309) ([Hao Chen](https://github.com/haoch)).
+* Throw error when `REPLACE` column transformer operates on non existing column. [#16183](https://github.com/ClickHouse/ClickHouse/pull/16183) ([hexiaoting](https://github.com/hexiaoting)).
+* Throw exception in case of not equi-join ON expression in RIGH|FULL JOIN. [#15162](https://github.com/ClickHouse/ClickHouse/pull/15162) ([Artem Zuikov](https://github.com/4ertus2)).
+
+
+#### Build/Testing/Packaging Improvement
+
+* Add simple integrity check for ClickHouse binary. It allows to detect corruption due to faulty hardware (bit rot on storage media or bit flips in RAM). [#18811](https://github.com/ClickHouse/ClickHouse/pull/18811) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Change `OpenSSL` to `BoringSSL`. It allows to avoid issues with sanitizers. This fixes [#12490](https://github.com/ClickHouse/ClickHouse/issues/12490). This fixes [#17502](https://github.com/ClickHouse/ClickHouse/issues/17502). This fixes [#12952](https://github.com/ClickHouse/ClickHouse/issues/12952). [#18129](https://github.com/ClickHouse/ClickHouse/pull/18129) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Simplify `Sys/V` init script. It was not working on Ubuntu 12.04 or older. [#17428](https://github.com/ClickHouse/ClickHouse/pull/17428) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Multiple improvements in `./clickhouse install` script. [#17421](https://github.com/ClickHouse/ClickHouse/pull/17421) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now ClickHouse can pretend to be a fake ZooKeeper. Currently, storage implementation is just stored in-memory hash-table, and server partially support ZooKeeper protocol. [#16877](https://github.com/ClickHouse/ClickHouse/pull/16877) ([alesapin](https://github.com/alesapin)).
+* Fix dead list watches removal for TestKeeperStorage (a mock for ZooKeeper). [#18065](https://github.com/ClickHouse/ClickHouse/pull/18065) ([alesapin](https://github.com/alesapin)).
+* Add `SYSTEM SUSPEND` command for fault injection. It can be used to faciliate failover tests. This closes [#15979](https://github.com/ClickHouse/ClickHouse/issues/15979). [#18850](https://github.com/ClickHouse/ClickHouse/pull/18850) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Generate build id when ClickHouse is linked with `lld`. It's appeared that `lld` does not generate it by default on my machine. Build id is used for crash reports and introspection. [#18808](https://github.com/ClickHouse/ClickHouse/pull/18808) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Fix shellcheck errors in style check. [#18566](https://github.com/ClickHouse/ClickHouse/pull/18566) ([Ilya Yatsishin](https://github.com/qoega)).
+* Update timezones info to 2020e. [#18531](https://github.com/ClickHouse/ClickHouse/pull/18531) ([alesapin](https://github.com/alesapin)).
+* Fix codespell warnings. Split style checks into separate parts. Update style checks docker image. [#18463](https://github.com/ClickHouse/ClickHouse/pull/18463) ([Ilya Yatsishin](https://github.com/qoega)).
+* Automated check for leftovers of conflict markers in docs. [#18332](https://github.com/ClickHouse/ClickHouse/pull/18332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Enable Thread Fuzzer for stateless tests flaky check. [#18299](https://github.com/ClickHouse/ClickHouse/pull/18299) ([alesapin](https://github.com/alesapin)).
+* Do not use non thread-safe function `strerror`. [#18204](https://github.com/ClickHouse/ClickHouse/pull/18204) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Update `anchore/scan-action@main` workflow action (was moved from `master` to `main`). [#18192](https://github.com/ClickHouse/ClickHouse/pull/18192) ([Stig Bakken](https://github.com/stigsb)).
+* Now `clickhouse-test` does DROP/CREATE databases with a timeout. [#18098](https://github.com/ClickHouse/ClickHouse/pull/18098) ([alesapin](https://github.com/alesapin)).
+* Enable experimental support for Pytest framework for stateless tests. [#17902](https://github.com/ClickHouse/ClickHouse/pull/17902) ([Ivan](https://github.com/abyss7)).
+* Now we use the fresh docker daemon version in integration tests. [#17671](https://github.com/ClickHouse/ClickHouse/pull/17671) ([alesapin](https://github.com/alesapin)).
+* Send info about official build, memory, cpu and free disk space to Sentry if it is enabled. Sentry is opt-in feature to help ClickHouse developers. This closes [#17279](https://github.com/ClickHouse/ClickHouse/issues/17279). [#17543](https://github.com/ClickHouse/ClickHouse/pull/17543) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* There was an uninitialized variable in the code of clickhouse-copier. [#17363](https://github.com/ClickHouse/ClickHouse/pull/17363) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix [one MSan report](https://clickhouse-test-reports.s3.yandex.net/17309/065cd002578f2e8228f12a2744bd40c970065e0c/stress_test_(memory)/stderr.log) from [#17309](https://github.com/ClickHouse/ClickHouse/issues/17309). [#17344](https://github.com/ClickHouse/ClickHouse/pull/17344) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
+* Fix for the issue with IPv6 in Arrow Flight library. See [the comments](https://github.com/ClickHouse/ClickHouse/pull/16243#issuecomment-720830294) for details. [#16664](https://github.com/ClickHouse/ClickHouse/pull/16664) ([Zhanna](https://github.com/FawnD2)).
+* Add a library that replaces some `libc` functions to traps that will terminate the process. [#16366](https://github.com/ClickHouse/ClickHouse/pull/16366) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Provide diagnostics in server logs in case of stack overflow, send error message to clickhouse-client. This closes [#14840](https://github.com/ClickHouse/ClickHouse/issues/14840). [#16346](https://github.com/ClickHouse/ClickHouse/pull/16346) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Now we can run almost all stateless functional tests in parallel. [#15236](https://github.com/ClickHouse/ClickHouse/pull/15236) ([alesapin](https://github.com/alesapin)).
+* Fix corruption in `librdkafka` snappy decompression (was a problem only for gcc10 builds, but official builds uses clang already, so at least recent official releases are not affected). [#18053](https://github.com/ClickHouse/ClickHouse/pull/18053) ([Azat Khuzhin](https://github.com/azat)).
+* If server was terminated by OOM killer, print message in log. [#13516](https://github.com/ClickHouse/ClickHouse/pull/13516) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* PODArray: Avoid call to memcpy with (nullptr, 0) arguments (Fix UBSan report). This fixes [#18525](https://github.com/ClickHouse/ClickHouse/issues/18525). [#18526](https://github.com/ClickHouse/ClickHouse/pull/18526) ([alexey-milovidov](https://github.com/alexey-milovidov)).
+* Minor improvement for path concatenation of zookeeper paths inside DDLWorker. [#17767](https://github.com/ClickHouse/ClickHouse/pull/17767) ([Bharat Nallan](https://github.com/bharatnc)).
+* Allow to reload symbols from debug file. This PR also fixes a build-id issue. [#17637](https://github.com/ClickHouse/ClickHouse/pull/17637) ([Amos Bird](https://github.com/amosbird)).
+
+
+## [Changelog for 2020](https://github.com/ClickHouse/ClickHouse/blob/master/docs/en/whats-new/changelog/2020.md)
diff --git a/docs/en/reference/whats-new/changelog/index.md b/docs/en/reference/whats-new/changelog/index.md
new file mode 100644
index 00000000000..517ea16f3e7
--- /dev/null
+++ b/docs/en/reference/whats-new/changelog/index.md
@@ -0,0 +1,7 @@
+---
+toc_folder_title: Changelog
+toc_priority: 74
+toc_title: '2022'
+---
+
+{% include "content/changelog.md" %}
diff --git a/docs/en/reference/whats-new/index.md b/docs/en/reference/whats-new/index.md
new file mode 100644
index 00000000000..8033fdf71d9
--- /dev/null
+++ b/docs/en/reference/whats-new/index.md
@@ -0,0 +1,8 @@
+---
+toc_folder_title: What's New
+toc_priority: 82
+---
+
+# What’s New in ClickHouse? {#whats-new-in-clickhouse}
+
+There’s a short high-level [roadmap](../whats-new/roadmap.md) and a detailed [changelog](../whats-new/changelog/index.md) for releases that have already been published.
diff --git a/docs/en/reference/whats-new/roadmap.md b/docs/en/reference/whats-new/roadmap.md
new file mode 100644
index 00000000000..54f8f9d68a3
--- /dev/null
+++ b/docs/en/reference/whats-new/roadmap.md
@@ -0,0 +1,10 @@
+---
+toc_priority: 74
+toc_title: Roadmap
+---
+
+# Roadmap {#roadmap}
+
+The roadmap for the year 2022 is published for open discussion [here](https://github.com/ClickHouse/ClickHouse/issues/32513).
+
+{## [Original article](https://clickhouse.com/docs/en/roadmap/) ##}
diff --git a/docs/en/reference/whats-new/security-changelog.md b/docs/en/reference/whats-new/security-changelog.md
new file mode 100644
index 00000000000..685f1c6d21d
--- /dev/null
+++ b/docs/en/reference/whats-new/security-changelog.md
@@ -0,0 +1,127 @@
+---
+toc_priority: 76
+toc_title: Security Changelog
+---
+## Fixed in ClickHouse 21.10.2.15, 2021-10-18 {#fixed-in-clickhouse-release-21-10-2-215-2021-10-18}
+
+### CVE-2021-43304 {#cve-2021-43304}
+
+Heap buffer overflow in Clickhouse's LZ4 compression codec when parsing a malicious query. There is no verification that the copy operations in the LZ4::decompressImpl loop and especially the arbitrary copy operation wildCopy<copy_amount>(op, ip, copy_end), don’t exceed the destination buffer’s limits.
+
+Credits: JFrog Security Research Team
+
+### CVE-2021-43305 {#cve-2021-43305}
+
+Heap buffer overflow in Clickhouse's LZ4 compression codec when parsing a malicious query. There is no verification that the copy operations in the LZ4::decompressImpl loop and especially the arbitrary copy operation wildCopy<copy_amount>(op, ip, copy_end), don’t exceed the destination buffer’s limits. This issue is very similar to CVE-2021-43304, but the vulnerable copy operation is in a different wildCopy call.
+
+Credits: JFrog Security Research Team
+
+### CVE-2021-42387 {#cve-2021-42387}
+
+Heap out-of-bounds read in Clickhouse's LZ4 compression codec when parsing a malicious query. As part of the LZ4::decompressImpl() loop, a 16-bit unsigned user-supplied value ('offset') is read from the compressed data. The offset is later used in the length of a copy operation, without checking the upper bounds of the source of the copy operation.
+
+Credits: JFrog Security Research Team
+
+### CVE-2021-42388 {#cve-2021-42388}
+
+Heap out-of-bounds read in Clickhouse's LZ4 compression codec when parsing a malicious query. As part of the LZ4::decompressImpl() loop, a 16-bit unsigned user-supplied value ('offset') is read from the compressed data. The offset is later used in the length of a copy operation, without checking the lower bounds of the source of the copy operation.
+
+Credits: JFrog Security Research Team
+
+### CVE-2021-42389 {#cve-2021-42389}
+
+Divide-by-zero in Clickhouse's Delta compression codec when parsing a malicious query. The first byte of the compressed buffer is used in a modulo operation without being checked for 0.
+
+Credits: JFrog Security Research Team
+
+### CVE-2021-42390 {#cve-2021-42390}
+
+Divide-by-zero in Clickhouse's DeltaDouble compression codec when parsing a malicious query. The first byte of the compressed buffer is used in a modulo operation without being checked for 0.
+
+Credits: JFrog Security Research Team
+
+### CVE-2021-42391 {#cve-2021-42391}
+
+Divide-by-zero in Clickhouse's Gorilla compression codec when parsing a malicious query. The first byte of the compressed buffer is used in a modulo operation without being checked for 0.
+
+Credits: JFrog Security Research Team
+
+## Fixed in ClickHouse 21.4.3.21, 2021-04-12 {#fixed-in-clickhouse-release-21-4-3-21-2021-04-12}
+
+### CVE-2021-25263 {#cve-2021-25263}
+
+An attacker that has CREATE DICTIONARY privilege, can read arbitary file outside permitted directory.
+
+Fix has been pushed to versions 20.8.18.32-lts, 21.1.9.41-stable, 21.2.9.41-stable, 21.3.6.55-lts, 21.4.3.21-stable and later.
+
+Credits: [Vyacheslav Egoshin](https://twitter.com/vegoshin)
+
+## Fixed in ClickHouse Release 19.14.3.3, 2019-09-10 {#fixed-in-clickhouse-release-19-14-3-3-2019-09-10}
+
+### CVE-2019-15024 {#cve-2019-15024}
+
+Аn attacker that has write access to ZooKeeper and who can run a custom server available from the network where ClickHouse runs, can create a custom-built malicious server that will act as a ClickHouse replica and register it in ZooKeeper. When another replica will fetch data part from the malicious replica, it can force clickhouse-server to write to arbitrary path on filesystem.
+
+Credits: Eldar Zaitov of Yandex Information Security Team
+
+### CVE-2019-16535 {#cve-2019-16535}
+
+Аn OOB read, OOB write and integer underflow in decompression algorithms can be used to achieve RCE or DoS via native protocol.
+
+Credits: Eldar Zaitov of Yandex Information Security Team
+
+### CVE-2019-16536 {#cve-2019-16536}
+
+Stack overflow leading to DoS can be triggered by a malicious authenticated client.
+
+Credits: Eldar Zaitov of Yandex Information Security Team
+
+## Fixed in ClickHouse Release 19.13.6.1, 2019-09-20 {#fixed-in-clickhouse-release-19-13-6-1-2019-09-20}
+
+### CVE-2019-18657 {#cve-2019-18657}
+
+Table function `url` had the vulnerability allowed the attacker to inject arbitrary HTTP headers in the request.
+
+Credits: [Nikita Tikhomirov](https://github.com/NSTikhomirov)
+
+## Fixed in ClickHouse Release 18.12.13, 2018-09-10 {#fixed-in-clickhouse-release-18-12-13-2018-09-10}
+
+### CVE-2018-14672 {#cve-2018-14672}
+
+Functions for loading CatBoost models allowed path traversal and reading arbitrary files through error messages.
+
+Credits: Andrey Krasichkov of Yandex Information Security Team
+
+## Fixed in ClickHouse Release 18.10.3, 2018-08-13 {#fixed-in-clickhouse-release-18-10-3-2018-08-13}
+
+### CVE-2018-14671 {#cve-2018-14671}
+
+unixODBC allowed loading arbitrary shared objects from the file system which led to a Remote Code Execution vulnerability.
+
+Credits: Andrey Krasichkov and Evgeny Sidorov of Yandex Information Security Team
+
+## Fixed in ClickHouse Release 1.1.54388, 2018-06-28 {#fixed-in-clickhouse-release-1-1-54388-2018-06-28}
+
+### CVE-2018-14668 {#cve-2018-14668}
+
+“remote” table function allowed arbitrary symbols in “user”, “password” and “default_database” fields which led to Cross Protocol Request Forgery Attacks.
+
+Credits: Andrey Krasichkov of Yandex Information Security Team
+
+## Fixed in ClickHouse Release 1.1.54390, 2018-07-06 {#fixed-in-clickhouse-release-1-1-54390-2018-07-06}
+
+### CVE-2018-14669 {#cve-2018-14669}
+
+ClickHouse MySQL client had “LOAD DATA LOCAL INFILE” functionality enabled that allowed a malicious MySQL database read arbitrary files from the connected ClickHouse server.
+
+Credits: Andrey Krasichkov and Evgeny Sidorov of Yandex Information Security Team
+
+## Fixed in ClickHouse Release 1.1.54131, 2017-01-10 {#fixed-in-clickhouse-release-1-1-54131-2017-01-10}
+
+### CVE-2018-14670 {#cve-2018-14670}
+
+Incorrect configuration in deb package could lead to the unauthorized use of the database.
+
+Credits: the UK’s National Cyber Security Centre (NCSC)
+
+{## [Original article](https://clickhouse.com/docs/en/security_changelog/) ##}