Remove managed iterator

Summary: Pull Request resolved: facebook#4124

Differential Revision: D8829910

Pulled By: siying

fbshipit-source-id: f3e952ccf3a631071a5d77c48e327046f8abb560

CMakeLists.txt

@@ -494,7 +494,6 @@ set(SOURCES
         db/log_reader.cc
         db/log_writer.cc
         db/malloc_stats.cc
-        db/managed_iterator.cc
         db/memtable.cc
         db/memtable_list.cc
         db/merge_helper.cc

HISTORY.md

@@ -5,6 +5,7 @@
 * With LRUCache, when high_pri_pool_ratio > 0, midpoint insertion strategy will be enabled to put low-pri items to the tail of low-pri list (the midpoint) when they first inserted into the cache. This is to make cache entries never get hit age out faster, improving cache efficiency when large background scan presents.
 * For bottommost_compression, a compatible CompressionOptions is added via `bottommost_compression_opts`. To keep backward compatible, a new boolean `enabled` is added to CompressionOptions. For compression_opts, it will be always used no matter what value of `enabled` is. For bottommost_compression_opts, it will only be used when user set `enabled=true`, otherwise, compression_opts will be used for bottommost_compression as default.
 * The "rocksdb.num.entries" table property no longer counts range deletion tombstones as entries.
+* Remove managed iterator. ReadOptions.managed is not effective anymore.
 
 ### New Features
 * Changes the format of index blocks by storing the key in their raw form rather than converting them to InternalKey. This saves 8 bytes per index key. The feature is backward compatbile but not forward compatible. It is disabled by default unless format_version 3 or above is used.

TARGETS

@@ -106,7 +106,6 @@ cpp_library(
         "db/log_writer.cc",
         "db/logs_with_prep_tracker.cc",
         "db/malloc_stats.cc",
-        "db/managed_iterator.cc",
         "db/memtable.cc",
         "db/memtable_list.cc",
         "db/merge_helper.cc",

db/db_impl.cc

@@ -41,7 +41,6 @@
 #include "db/log_reader.h"
 #include "db/log_writer.h"
 #include "db/malloc_stats.h"
-#include "db/managed_iterator.h"
 #include "db/memtable.h"
 #include "db/memtable_list.h"
 #include "db/merge_context.h"
@@ -1578,6 +1577,10 @@ bool DBImpl::KeyMayExist(const ReadOptions& read_options,
 
 Iterator* DBImpl::NewIterator(const ReadOptions& read_options,
                               ColumnFamilyHandle* column_family) {
+  if (read_options.managed) {
+    return NewErrorIterator(
+        Status::NotSupported("Managed iterator is not supported anymore."));
+  }
   Iterator* result = nullptr;
   if (read_options.read_tier == kPersistedTier) {
     return NewErrorIterator(Status::NotSupported(
@@ -1595,22 +1598,7 @@ Iterator* DBImpl::NewIterator(const ReadOptions& read_options,
   auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
   auto cfd = cfh->cfd();
   ReadCallback* read_callback = nullptr;  // No read callback provided.
-  if (read_options.managed) {
-#ifdef ROCKSDB_LITE
-    // not supported in lite version
-    result = NewErrorIterator(Status::InvalidArgument(
-        "Managed Iterators not supported in RocksDBLite."));
-#else
-    if ((read_options.tailing) || (read_options.snapshot != nullptr) ||
-        (is_snapshot_supported_)) {
-      result = new ManagedIterator(this, read_options, cfd);
-    } else {
-      // Managed iter not supported
-      result = NewErrorIterator(Status::InvalidArgument(
-          "Managed Iterators not supported without snapshots."));
-    }
-#endif
-  } else if (read_options.tailing) {
+if (read_options.tailing) {
 #ifdef ROCKSDB_LITE
     // not supported in lite version
     result = nullptr;
@@ -1705,30 +1693,17 @@ Status DBImpl::NewIterators(
     const ReadOptions& read_options,
     const std::vector<ColumnFamilyHandle*>& column_families,
     std::vector<Iterator*>* iterators) {
+  if (read_options.managed) {
+    return Status::NotSupported("Managed iterator is not supported anymore.");
+  }
   if (read_options.read_tier == kPersistedTier) {
     return Status::NotSupported(
         "ReadTier::kPersistedData is not yet supported in iterators.");
   }
   ReadCallback* read_callback = nullptr;  // No read callback provided.
   iterators->clear();
   iterators->reserve(column_families.size());
-  if (read_options.managed) {
-#ifdef ROCKSDB_LITE
-    return Status::InvalidArgument(
-        "Managed interator not supported in RocksDB lite");
-#else
-    if ((!read_options.tailing) && (read_options.snapshot == nullptr) &&
-        (!is_snapshot_supported_)) {
-      return Status::InvalidArgument(
-          "Managed interator not supported without snapshots");
-    }
-    for (auto cfh : column_families) {
-      auto cfd = reinterpret_cast<ColumnFamilyHandleImpl*>(cfh)->cfd();
-      auto iter = new ManagedIterator(this, read_options, cfd);
-      iterators->push_back(iter);
-    }
-#endif
-  } else if (read_options.tailing) {
+  if (read_options.tailing) {
 #ifdef ROCKSDB_LITE
     return Status::InvalidArgument(
         "Tailing interator not supported in RocksDB lite");

db/db_iterator_test.cc

@@ -184,73 +184,6 @@ TEST_P(DBIteratorTest, NonBlockingIteration) {
                          kSkipMmapReads));
 }
 
-#ifndef ROCKSDB_LITE
-TEST_P(DBIteratorTest, ManagedNonBlockingIteration) {
-  do {
-    ReadOptions non_blocking_opts, regular_opts;
-    Options options = CurrentOptions();
-    options.statistics = rocksdb::CreateDBStatistics();
-    non_blocking_opts.read_tier = kBlockCacheTier;
-    non_blocking_opts.managed = true;
-    CreateAndReopenWithCF({"pikachu"}, options);
-    // write one kv to the database.
-    ASSERT_OK(Put(1, "a", "b"));
-
-    // scan using non-blocking iterator. We should find it because
-    // it is in memtable.
-    Iterator* iter = NewIterator(non_blocking_opts, handles_[1]);
-    int count = 0;
-    for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
-      ASSERT_OK(iter->status());
-      count++;
-    }
-    ASSERT_EQ(count, 1);
-    delete iter;
-
-    // flush memtable to storage. Now, the key should not be in the
-    // memtable neither in the block cache.
-    ASSERT_OK(Flush(1));
-
-    // verify that a non-blocking iterator does not find any
-    // kvs. Neither does it do any IOs to storage.
-    int64_t numopen = TestGetTickerCount(options, NO_FILE_OPENS);
-    int64_t cache_added = TestGetTickerCount(options, BLOCK_CACHE_ADD);
-    iter = NewIterator(non_blocking_opts, handles_[1]);
-    count = 0;
-    for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
-      count++;
-    }
-    ASSERT_EQ(count, 0);
-    ASSERT_TRUE(iter->status().IsIncomplete());
-    ASSERT_EQ(numopen, TestGetTickerCount(options, NO_FILE_OPENS));
-    ASSERT_EQ(cache_added, TestGetTickerCount(options, BLOCK_CACHE_ADD));
-    delete iter;
-
-    // read in the specified block via a regular get
-    ASSERT_EQ(Get(1, "a"), "b");
-
-    // verify that we can find it via a non-blocking scan
-    numopen = TestGetTickerCount(options, NO_FILE_OPENS);
-    cache_added = TestGetTickerCount(options, BLOCK_CACHE_ADD);
-    iter = NewIterator(non_blocking_opts, handles_[1]);
-    count = 0;
-    for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
-      ASSERT_OK(iter->status());
-      count++;
-    }
-    ASSERT_EQ(count, 1);
-    ASSERT_EQ(numopen, TestGetTickerCount(options, NO_FILE_OPENS));
-    ASSERT_EQ(cache_added, TestGetTickerCount(options, BLOCK_CACHE_ADD));
-    delete iter;
-
-    // This test verifies block cache behaviors, which is not used by plain
-    // table format.
-    // Exclude kHashCuckoo as it does not support iteration currently
-  } while (ChangeOptions(kSkipPlainTable | kSkipNoSeekToLast | kSkipHashCuckoo |
-                         kSkipMmapReads));
-}
-#endif  // ROCKSDB_LITE
-
 TEST_P(DBIteratorTest, IterSeekBeforePrev) {
   ASSERT_OK(Put("a", "b"));
   ASSERT_OK(Put("c", "d"));