tidb: enable to forbid to retry when commit, add isolation test. (pin…

…gcap#5990)

isolation_test.go

@@ -0,0 +1,263 @@
+// Copyright 2018 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tidb_test
+
+import (
+	. "github.com/pingcap/check"
+	"github.com/pingcap/tidb"
+	"github.com/pingcap/tidb/domain"
+	"github.com/pingcap/tidb/kv"
+	"github.com/pingcap/tidb/store/mockstore"
+	"github.com/pingcap/tidb/store/mockstore/mocktikv"
+	"github.com/pingcap/tidb/util/testkit"
+	"github.com/pingcap/tidb/util/testleak"
+)
+
+var _ = Suite(&testIsolationSuite{})
+
+type testIsolationSuite struct {
+	cluster   *mocktikv.Cluster
+	mvccStore *mocktikv.MvccStore
+	store     kv.Storage
+	dom       *domain.Domain
+}
+
+func (s *testIsolationSuite) SetUpSuite(c *C) {
+	testleak.BeforeTest()
+	s.cluster = mocktikv.NewCluster()
+	mocktikv.BootstrapWithSingleStore(s.cluster)
+	s.mvccStore = mocktikv.NewMvccStore()
+	store, err := mockstore.NewMockTikvStore(
+		mockstore.WithCluster(s.cluster),
+		mockstore.WithMVCCStore(s.mvccStore),
+	)
+	c.Assert(err, IsNil)
+	s.store = store
+	tidb.SetSchemaLease(0)
+	tidb.SetStatsLease(0)
+	s.dom, err = tidb.BootstrapSession(s.store)
+	c.Assert(err, IsNil)
+	tidb.SetCommitRetryLimit(0)
+}
+
+func (s *testIsolationSuite) TearDownSuite(c *C) {
+	tidb.SetCommitRetryLimit(10)
+	s.dom.Close()
+	s.store.Close()
+	testleak.AfterTest(c)()
+}
+
+/*
+These test cases come from the paper <A Critique of ANSI SQL Isolation Levels>.
+The sign 'P0', 'P1'.... can be found in the paper. These cases will run under snapshot isolation.
+*/
+func (s *testIsolationSuite) TestP0DirtyWrite(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+
+	session1.MustExec("begin;")
+	session1.MustExec("update x set c = c+1 where id = 1;")
+	session2.MustExec("begin;")
+	session2.MustExec("update x set c = c+1 where id = 1;")
+	session1.MustExec("commit;")
+	_, err := session2.Exec("commit;")
+	c.Assert(err, NotNil)
+}
+
+func (s *testIsolationSuite) TestP1DirtyRead(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+
+	session1.MustExec("begin;")
+	session1.MustExec("update x set c = c+1 where id = 1;")
+	session2.MustExec("begin;")
+	session2.MustQuery("select c from x where id = 1;").Check(testkit.Rows("1"))
+	session1.MustExec("commit;")
+	session2.MustExec("commit;")
+}
+
+func (s *testIsolationSuite) TestP2NonRepeatableRead(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("drop table if exists y;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+	session1.MustExec("create table y (id int primary key, c int);")
+	session1.MustExec("insert into y values(1, 1);")
+
+	session1.MustExec("begin;")
+	session2.MustExec("begin;")
+	session1.MustQuery("select c from x where id = 1;").Check(testkit.Rows("1"))
+	session2.MustQuery("select c from x where id = 1;").Check(testkit.Rows("1"))
+	session2.MustExec("update x set c = c+1 where id = 1;")
+	session2.MustQuery("select c from y where id = 1;").Check(testkit.Rows("1"))
+	session2.MustExec("update y set c = c+1 where id = 1;")
+	session2.MustExec("commit;")
+	session1.MustQuery("select c from y where id = 1;").Check(testkit.Rows("1"))
+	session1.MustExec("commit;")
+}
+
+func (s *testIsolationSuite) TestP3Phantom(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("drop table if exists z;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+	session1.MustExec("create table z (id int primary key, c int);")
+	session1.MustExec("insert into z values(1, 1);")
+
+	session1.MustExec("begin;")
+	session2.MustExec("begin;")
+	session1.MustQuery("select c from x where id < 5;").Check(testkit.Rows("1"))
+	session2.MustExec("insert into x values(2, 1);")
+	session2.MustQuery("select c from z where id = 1;").Check(testkit.Rows("1"))
+	session2.MustExec("update z set c = c+1 where id = 1;")
+	session2.MustExec("commit;")
+	session1.MustQuery("select c from z where id = 1;").Check(testkit.Rows("1"))
+	session1.MustExec("commit;")
+}
+
+func (s *testIsolationSuite) TestP4LostUpdate(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+
+	session1.MustExec("begin;")
+	session1.MustQuery("select c from x where id = 1;").Check(testkit.Rows("1"))
+	session2.MustExec("begin;")
+	session2.MustQuery("select c from x where id = 1;").Check(testkit.Rows("1"))
+	session2.MustExec("update x set c = c+1 where id = 1;")
+	session2.MustExec("commit;")
+	session1.MustExec("update x set c = c+1 where id = 1;")
+	_, err := session1.Exec("commit;")
+	c.Assert(err, NotNil)
+}
+
+// cursor is not supported
+func (s *testIsolationSuite) TestP4CLostUpdate(c *C) {}
+
+func (s *testIsolationSuite) TestA3Phantom(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+
+	session1.MustExec("begin;")
+	session2.MustExec("begin;")
+	session2.MustQuery("select c from x where id < 5;").Check(testkit.Rows("1"))
+	session1.MustExec("insert into x values(2, 1);")
+	session1.MustExec("commit;")
+	session2.MustQuery("select c from x where id < 5;").Check(testkit.Rows("1"))
+	session2.MustExec("commit;")
+}
+
+func (s *testIsolationSuite) TestA5AReadSkew(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("drop table if exists y;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+	session1.MustExec("create table y (id int primary key, c int);")
+	session1.MustExec("insert into y values(1, 1);")
+
+	session1.MustExec("begin;")
+	session2.MustExec("begin;")
+	session1.MustQuery("select c from x where id = 1;").Check(testkit.Rows("1"))
+	session2.MustExec("update x set c = c+1 where id = 1;")
+	session2.MustExec("update y set c = c+1 where id = 1;")
+	session2.MustExec("commit;")
+	session1.MustQuery("select c from y where id = 1;").Check(testkit.Rows("1"))
+	session1.MustExec("commit;")
+}
+
+func (s *testIsolationSuite) TestA5BWriteSkew(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("drop table if exists y;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+	session1.MustExec("create table y (id int primary key, c int);")
+	session1.MustExec("insert into y values(1, 1);")
+
+	session1.MustExec("begin;")
+	session2.MustExec("begin;")
+	session1.MustQuery("select c from x where id = 1;").Check(testkit.Rows("1"))
+	session2.MustQuery("select c from y where id = 1;").Check(testkit.Rows("1"))
+	session1.MustExec("update y set c = c+1 where id = 1;")
+	session2.MustExec("update x set c = c+1 where id = 1;")
+	session2.MustExec("commit;")
+	session1.MustExec("commit;")
+}
+
+/*
+These test cases come from the paper <Highly Available Transactions: Virtues and Limitations>
+for tidb, we support read-after-write on cluster level.
+*/
+func (s *testIsolationSuite) TestReadAfterWrite(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+
+	session1.MustExec("begin;")
+	session1.MustExec("update x set c = c+1 where id = 1;")
+	session1.MustExec("commit;")
+	session1.MustExec("begin;")
+	session2.MustQuery("select c from x where id = 1;").Check(testkit.Rows("2"))
+	session2.MustExec("commit;")
+}
+
+/*
+This case will do harm in Innodb, even if in snapshot isolation, but harmless in tidb.
+*/
+func (s *testIsolationSuite) TestPhantomReadInInnodb(c *C) {
+	session1 := testkit.NewTestKitWithInit(c, s.store)
+	session2 := testkit.NewTestKitWithInit(c, s.store)
+
+	session1.MustExec("drop table if exists x;")
+	session1.MustExec("create table x (id int primary key, c int);")
+	session1.MustExec("insert into x values(1, 1);")
+
+	session1.MustExec("begin;")
+	session1.MustQuery("select c from x where id < 5;").Check(testkit.Rows("1"))
+	session2.MustExec("begin;")
+	session2.MustExec("insert into x values(2, 1);")
+	session2.MustExec("commit;")
+	session1.MustExec("update x set c = c+1 where id < 5;")
+	session1.MustQuery("select c from x where id < 5;").Check(testkit.Rows("2"))
+	session1.MustExec("commit;")
+}

session.go

@@ -336,7 +336,7 @@ func (s *session) doCommitWithRetry(ctx context.Context) error {
 		// Don't retry in BatchInsert mode. As a counter-example, insert into t1 select * from t2,
 		// BatchInsert already commit the first batch 1000 rows, then it commit 1000-2000 and retry the statement,
 		// Finally t1 will have more data than t2, with no errors return to user!
-		if s.isRetryableError(err) && !s.sessionVars.BatchInsert {
+		if s.isRetryableError(err) && !s.sessionVars.BatchInsert && commitRetryLimit != 0 {
 			log.Warnf("[%d] retryable error: %v, txn: %v", s.sessionVars.ConnectionID, err, s.txn)
 			// Transactions will retry 2 ~ commitRetryLimit times.
 			// We make larger transactions retry less times to prevent cluster resource outage.