Files
tidb/session/schema_test.go

682 lines
23 KiB
Go

// Copyright 2022 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,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package session_test
import (
"context"
"fmt"
"testing"
"time"
"github.com/pingcap/failpoint"
"github.com/pingcap/tidb/domain"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/parser/model"
"github.com/pingcap/tidb/parser/terror"
plannercore "github.com/pingcap/tidb/planner/core"
"github.com/pingcap/tidb/server"
"github.com/pingcap/tidb/session"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/store/mockstore"
"github.com/pingcap/tidb/tablecodec"
"github.com/pingcap/tidb/testkit"
"github.com/stretchr/testify/require"
"github.com/tikv/client-go/v2/testutils"
)
func createMockStoreForSchemaTest(t *testing.T, opts ...mockstore.MockTiKVStoreOption) kv.Storage {
store, err := mockstore.NewMockStore(opts...)
require.NoError(t, err)
session.DisableStats4Test()
dom, err := session.BootstrapSession(store)
require.NoError(t, err)
dom.SetStatsUpdating(true)
sv := server.CreateMockServer(t, store)
sv.SetDomain(dom)
dom.InfoSyncer().SetSessionManager(sv)
t.Cleanup(func() {
dom.Close()
require.NoError(t, store.Close())
})
return store
}
func TestPrepareStmtCommitWhenSchemaChanged(t *testing.T) {
store := createMockStoreForSchemaTest(t)
setTxnTk := testkit.NewTestKit(t, store)
setTxnTk.MustExec("set global tidb_txn_mode=''")
tk1 := testkit.NewTestKit(t, store)
tk2 := testkit.NewTestKit(t, store)
tk1.MustExec("use test")
tk1.MustExec("set global tidb_enable_metadata_lock=0")
tk2.MustExec("use test")
tk1.MustExec("create table t (a int, b int)")
tk2.MustExec("prepare stmt from 'insert into t values (?, ?)'")
tk2.MustExec("set @a = 1")
// Commit find unrelated schema change.
tk2.MustExec("begin")
tk1.MustExec("create table t1 (id int)")
tk2.MustExec("execute stmt using @a, @a")
tk2.MustExec("commit")
tk2.MustExec("set @@tidb_disable_txn_auto_retry = 0")
tk2.MustExec("begin")
tk1.MustExec("alter table t drop column b")
tk2.MustExec("execute stmt using @a, @a")
err := tk2.ExecToErr("commit")
require.True(t, terror.ErrorEqual(err, plannercore.ErrWrongValueCountOnRow), fmt.Sprintf("err %v", err))
}
func TestCommitWhenSchemaChanged(t *testing.T) {
store := createMockStoreForSchemaTest(t)
setTxnTk := testkit.NewTestKit(t, store)
setTxnTk.MustExec("set global tidb_txn_mode=''")
setTxnTk.MustExec("set global tidb_enable_metadata_lock=0")
tk1 := testkit.NewTestKit(t, store)
tk2 := testkit.NewTestKit(t, store)
tk1.MustExec("use test")
tk2.MustExec("use test")
tk1.MustExec("create table t (a int, b int)")
tk2.MustExec("set @@tidb_disable_txn_auto_retry = 0")
tk2.MustExec("begin")
tk2.MustExec("insert into t values (1, 1)")
tk1.MustExec("alter table t drop column b")
// When tk2 commit, it will find schema already changed.
tk2.MustExec("insert into t values (4, 4)")
err := tk2.ExecToErr("commit")
require.True(t, terror.ErrorEqual(err, plannercore.ErrWrongValueCountOnRow), fmt.Sprintf("err %v", err))
}
func TestRetrySchemaChangeForEmptyChange(t *testing.T) {
store := createMockStoreForSchemaTest(t)
setTxnTk := testkit.NewTestKit(t, store)
setTxnTk.MustExec("set global tidb_txn_mode=''")
tk1 := testkit.NewTestKit(t, store)
tk2 := testkit.NewTestKit(t, store)
tk1.MustExec("use test")
tk2.MustExec("use test")
tk1.MustExec("create table t (i int)")
tk1.MustExec("create table t1 (i int)")
tk1.MustExec("begin")
tk2.MustExec("alter table t add j int")
tk1.MustExec("select * from t for update")
tk1.MustExec("update t set i = -i")
tk1.MustExec("delete from t")
tk1.MustExec("insert into t1 values (1)")
tk1.MustExec("commit")
}
func TestRetrySchemaChange(t *testing.T) {
store := createMockStoreForSchemaTest(t)
setTxnTk := testkit.NewTestKit(t, store)
setTxnTk.MustExec("set global tidb_txn_mode=''")
setTxnTk.MustExec("set global tidb_enable_metadata_lock=0")
tk1 := testkit.NewTestKit(t, store)
tk2 := testkit.NewTestKit(t, store)
tk1.MustExec("use test")
tk2.MustExec("use test")
tk1.MustExec("create table t (a int primary key, b int)")
tk1.MustExec("insert into t values (1, 1)")
tk2.MustExec("set @@tidb_disable_txn_auto_retry = 0")
tk2.MustExec("begin")
tk2.MustExec("update t set b = 5 where a = 1")
tk1.MustExec("alter table t add index b_i (b)")
run := false
hook := func() {
if !run {
tk1.MustExec("update t set b = 3 where a = 1")
run = true
}
}
// In order to cover a bug that statement history is not updated during retry.
// See https://github.com/pingcap/tidb/pull/5202
// Step1: when tk2 commit, it find schema changed and retry().
// Step2: during retry, hook() is called, tk1 update primary key.
// Step3: tk2 continue commit in retry() meet a retryable error(write conflict), retry again.
// Step4: tk2 retry() success, if it use the stale statement, data and index will inconsistent.
fpName := "github.com/pingcap/tidb/session/preCommitHook"
require.NoError(t, failpoint.Enable(fpName, "return"))
defer func() { require.NoError(t, failpoint.Disable(fpName)) }()
ctx := context.WithValue(context.Background(), "__preCommitHook", hook)
require.NoError(t, tk2.Session().CommitTxn(ctx))
tk1.MustQuery("select * from t where t.b = 5").Check(testkit.Rows("1 5"))
}
func TestRetryMissingUnionScan(t *testing.T) {
store := createMockStoreForSchemaTest(t)
setTxnTk := testkit.NewTestKit(t, store)
setTxnTk.MustExec("set global tidb_txn_mode=''")
tk1 := testkit.NewTestKit(t, store)
tk2 := testkit.NewTestKit(t, store)
tk1.MustExec("use test")
tk2.MustExec("use test")
tk1.MustExec("create table t (a int primary key, b int unique, c int)")
tk1.MustExec("insert into t values (1, 1, 1)")
tk2.MustExec("set @@tidb_disable_txn_auto_retry = 0")
tk2.MustExec("begin")
tk2.MustExec("update t set b = 1, c = 2 where b = 2")
tk2.MustExec("update t set b = 1, c = 2 where a = 1")
// Create a conflict to reproduces the bug that the second update statement in retry
// has a dirty table but doesn't use UnionScan.
tk1.MustExec("update t set b = 2 where a = 1")
tk2.MustExec("commit")
}
func TestTableReaderChunk(t *testing.T) {
// Since normally a single region mock tikv only returns one partial result we need to manually split the
// table to test multiple chunks.
var cluster testutils.Cluster
store := testkit.CreateMockStore(t, mockstore.WithClusterInspector(func(c testutils.Cluster) {
mockstore.BootstrapWithSingleStore(c)
cluster = c
}))
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
tk.MustExec("create table chk (a int)")
for i := 0; i < 100; i++ {
tk.MustExec(fmt.Sprintf("insert chk values (%d)", i))
}
tbl, err := domain.GetDomain(tk.Session()).InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("chk"))
require.NoError(t, err)
tableStart := tablecodec.GenTableRecordPrefix(tbl.Meta().ID)
cluster.SplitKeys(tableStart, tableStart.PrefixNext(), 10)
tk.Session().GetSessionVars().SetDistSQLScanConcurrency(1)
tk.MustExec("set tidb_init_chunk_size = 2")
defer func() {
tk.MustExec(fmt.Sprintf("set tidb_init_chunk_size = %d", variable.DefInitChunkSize))
}()
rs, err := tk.Exec("select * from chk")
require.NoError(t, err)
defer func() { require.NoError(t, rs.Close()) }()
req := rs.NewChunk(nil)
var count int
var numChunks int
for {
err = rs.Next(context.TODO(), req)
require.NoError(t, err)
numRows := req.NumRows()
if numRows == 0 {
break
}
for i := 0; i < numRows; i++ {
require.Equal(t, int64(count), req.GetRow(i).GetInt64(0))
count++
}
numChunks++
}
require.Equal(t, 100, count)
// FIXME: revert this result to new group value after distsql can handle initChunkSize.
require.Equal(t, 1, numChunks)
}
func TestInsertExecChunk(t *testing.T) {
store := createMockStoreForSchemaTest(t)
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
tk.MustExec("create table test1(a int)")
for i := 0; i < 100; i++ {
tk.MustExec(fmt.Sprintf("insert test1 values (%d)", i))
}
tk.MustExec("create table test2(a int)")
tk.Session().GetSessionVars().SetDistSQLScanConcurrency(1)
tk.MustExec("insert into test2(a) select a from test1;")
rs, err := tk.Exec("select * from test2")
require.NoError(t, err)
defer func() { require.NoError(t, rs.Close()) }()
var idx int
for {
req := rs.NewChunk(nil)
err = rs.Next(context.TODO(), req)
require.NoError(t, err)
if req.NumRows() == 0 {
break
}
for rowIdx := 0; rowIdx < req.NumRows(); rowIdx++ {
row := req.GetRow(rowIdx)
require.Equal(t, int64(idx), row.GetInt64(0))
idx++
}
}
require.Equal(t, 100, idx)
}
func TestUpdateExecChunk(t *testing.T) {
store := createMockStoreForSchemaTest(t)
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
tk.MustExec("create table chk(a int)")
for i := 0; i < 100; i++ {
tk.MustExec(fmt.Sprintf("insert chk values (%d)", i))
}
tk.Session().GetSessionVars().SetDistSQLScanConcurrency(1)
for i := 0; i < 100; i++ {
tk.MustExec(fmt.Sprintf("update chk set a = a + 100 where a = %d", i))
}
rs, err := tk.Exec("select * from chk")
require.NoError(t, err)
defer func() { require.NoError(t, rs.Close()) }()
var idx int
for {
req := rs.NewChunk(nil)
err = rs.Next(context.TODO(), req)
require.NoError(t, err)
if req.NumRows() == 0 {
break
}
for rowIdx := 0; rowIdx < req.NumRows(); rowIdx++ {
row := req.GetRow(rowIdx)
require.Equal(t, int64(idx+100), row.GetInt64(0))
idx++
}
}
require.Equal(t, 100, idx)
}
func TestDeleteExecChunk(t *testing.T) {
store := createMockStoreForSchemaTest(t)
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
tk.MustExec("create table chk(a int)")
for i := 0; i < 100; i++ {
tk.MustExec(fmt.Sprintf("insert chk values (%d)", i))
}
tk.Session().GetSessionVars().SetDistSQLScanConcurrency(1)
for i := 0; i < 99; i++ {
tk.MustExec(fmt.Sprintf("delete from chk where a = %d", i))
}
rs, err := tk.Exec("select * from chk")
require.NoError(t, err)
defer func() { require.NoError(t, rs.Close()) }()
req := rs.NewChunk(nil)
err = rs.Next(context.TODO(), req)
require.NoError(t, err)
require.Equal(t, 1, req.NumRows())
row := req.GetRow(0)
require.Equal(t, int64(99), row.GetInt64(0))
}
func TestDeleteMultiTableExecChunk(t *testing.T) {
store := createMockStoreForSchemaTest(t)
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
tk.MustExec("create table chk1(a int)")
tk.MustExec("create table chk2(a int)")
for i := 0; i < 100; i++ {
tk.MustExec(fmt.Sprintf("insert chk1 values (%d)", i))
}
for i := 0; i < 50; i++ {
tk.MustExec(fmt.Sprintf("insert chk2 values (%d)", i))
}
tk.Session().GetSessionVars().SetDistSQLScanConcurrency(1)
tk.MustExec("delete chk1, chk2 from chk1 inner join chk2 where chk1.a = chk2.a")
rs, err := tk.Exec("select * from chk1")
require.NoError(t, err)
var idx int
for {
req := rs.NewChunk(nil)
err = rs.Next(context.TODO(), req)
require.NoError(t, err)
if req.NumRows() == 0 {
break
}
for i := 0; i < req.NumRows(); i++ {
row := req.GetRow(i)
require.Equal(t, int64(idx+50), row.GetInt64(0))
idx++
}
}
require.Equal(t, 50, idx)
require.NoError(t, rs.Close())
rs, err = tk.Exec("select * from chk2")
require.NoError(t, err)
req := rs.NewChunk(nil)
err = rs.Next(context.TODO(), req)
require.NoError(t, err)
require.Equal(t, 0, req.NumRows())
require.NoError(t, rs.Close())
}
func TestIndexLookUpReaderChunk(t *testing.T) {
// Since normally a single region mock tikv only returns one partial result we need to manually split the
// table to test multiple chunks.
var cluster testutils.Cluster
store := testkit.CreateMockStore(t, mockstore.WithClusterInspector(func(c testutils.Cluster) {
mockstore.BootstrapWithSingleStore(c)
cluster = c
}))
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
tk.MustExec("drop table if exists chk")
tk.MustExec("create table chk (k int unique, c int)")
for i := 0; i < 100; i++ {
tk.MustExec(fmt.Sprintf("insert chk values (%d, %d)", i, i))
}
tbl, err := domain.GetDomain(tk.Session()).InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("chk"))
require.NoError(t, err)
indexStart := tablecodec.EncodeTableIndexPrefix(tbl.Meta().ID, tbl.Indices()[0].Meta().ID)
cluster.SplitKeys(indexStart, indexStart.PrefixNext(), 10)
tk.Session().GetSessionVars().IndexLookupSize = 10
rs, err := tk.Exec("select * from chk order by k")
require.NoError(t, err)
req := rs.NewChunk(nil)
var count int
for {
err = rs.Next(context.TODO(), req)
require.NoError(t, err)
numRows := req.NumRows()
if numRows == 0 {
break
}
for i := 0; i < numRows; i++ {
require.Equal(t, int64(count), req.GetRow(i).GetInt64(0))
require.Equal(t, int64(count), req.GetRow(i).GetInt64(1))
count++
}
}
require.Equal(t, 100, count)
require.NoError(t, rs.Close())
rs, err = tk.Exec("select k from chk where c < 90 order by k")
require.NoError(t, err)
req = rs.NewChunk(nil)
count = 0
for {
err = rs.Next(context.TODO(), req)
require.NoError(t, err)
numRows := req.NumRows()
if numRows == 0 {
break
}
for i := 0; i < numRows; i++ {
require.Equal(t, int64(count), req.GetRow(i).GetInt64(0))
count++
}
}
require.Equal(t, 90, count)
require.NoError(t, rs.Close())
}
func TestTxnSize(t *testing.T) {
store := createMockStoreForSchemaTest(t)
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
tk.MustExec("drop table if exists txn_size")
tk.MustExec("create table txn_size (k int , v varchar(64))")
tk.MustExec("begin")
tk.MustExec("insert txn_size values (1, 'dfaasdfsdf')")
tk.MustExec("insert txn_size values (2, 'dsdfaasdfsdf')")
tk.MustExec("insert txn_size values (3, 'abcdefghijkl')")
txn, err := tk.Session().Txn(false)
require.NoError(t, err)
require.Greater(t, txn.Size(), 0)
}
func TestValidationRecursion(t *testing.T) {
// We have to expect that validation functions will call GlobalVarsAccessor.GetGlobalSysVar().
// This tests for a regression where GetGlobalSysVar() can not safely call the validation
// function because it might cause infinite recursion.
// See: https://github.com/pingcap/tidb/issues/30255
sv := variable.SysVar{Scope: variable.ScopeGlobal, Name: "mynewsysvar", Value: "test", Validation: func(vars *variable.SessionVars, normalizedValue string, originalValue string, scope variable.ScopeFlag) (string, error) {
return vars.GlobalVarsAccessor.GetGlobalSysVar("mynewsysvar")
}}
variable.RegisterSysVar(&sv)
store := createMockStoreForSchemaTest(t)
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
val, err := sv.Validate(tk.Session().GetSessionVars(), "test2", variable.ScopeGlobal)
require.NoError(t, err)
require.Equal(t, "test", val)
}
func TestGlobalAndLocalTxn(t *testing.T) {
// Because the PD config of check_dev_2 test is not compatible with local/global txn yet,
// so we will skip this test for now.
store := testkit.CreateMockStore(t)
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
tk.MustExec("set global tidb_enable_local_txn = on;")
tk.MustExec("drop table if exists t1")
tk.MustExec("drop placement policy if exists p1")
tk.MustExec("drop placement policy if exists p2")
tk.MustExec("create placement policy p1 leader_constraints='[+zone=dc-1]'")
tk.MustExec("create placement policy p2 leader_constraints='[+zone=dc-2]'")
tk.MustExec(`create table t1 (c int)
PARTITION BY RANGE (c) (
PARTITION p0 VALUES LESS THAN (100) placement policy p1,
PARTITION p1 VALUES LESS THAN (200) placement policy p2
);`)
defer func() {
tk.MustExec("drop table if exists t1")
tk.MustExec("drop placement policy if exists p1")
tk.MustExec("drop placement policy if exists p2")
}()
// set txn_scope to global
tk.MustExec(fmt.Sprintf("set @@session.txn_scope = '%s';", kv.GlobalTxnScope))
result := tk.MustQuery("select @@txn_scope;")
result.Check(testkit.Rows(kv.GlobalTxnScope))
// test global txn auto commit
tk.MustExec("insert into t1 (c) values (1)") // write dc-1 with global scope
result = tk.MustQuery("select * from t1") // read dc-1 and dc-2 with global scope
require.Equal(t, 1, len(result.Rows()))
// begin and commit with global txn scope
tk.MustExec("begin")
txn, err := tk.Session().Txn(true)
require.NoError(t, err)
require.Equal(t, kv.GlobalTxnScope, tk.Session().GetSessionVars().TxnCtx.TxnScope)
require.True(t, txn.Valid())
tk.MustExec("insert into t1 (c) values (1)") // write dc-1 with global scope
result = tk.MustQuery("select * from t1") // read dc-1 and dc-2 with global scope
require.Equal(t, 2, len(result.Rows()))
require.True(t, txn.Valid())
tk.MustExec("commit")
result = tk.MustQuery("select * from t1")
require.Equal(t, 2, len(result.Rows()))
// begin and rollback with global txn scope
tk.MustExec("begin")
txn, err = tk.Session().Txn(true)
require.NoError(t, err)
require.Equal(t, kv.GlobalTxnScope, tk.Session().GetSessionVars().TxnCtx.TxnScope)
require.True(t, txn.Valid())
tk.MustExec("insert into t1 (c) values (101)") // write dc-2 with global scope
result = tk.MustQuery("select * from t1") // read dc-1 and dc-2 with global scope
require.Equal(t, 3, len(result.Rows()))
require.True(t, txn.Valid())
tk.MustExec("rollback")
result = tk.MustQuery("select * from t1")
require.Equal(t, 2, len(result.Rows()))
timeBeforeWriting := time.Now()
tk.MustExec("insert into t1 (c) values (101)") // write dc-2 with global scope
result = tk.MustQuery("select * from t1") // read dc-1 and dc-2 with global scope
require.Equal(t, 3, len(result.Rows()))
failpoint.Enable("tikvclient/injectTxnScope", `return("dc-1")`)
defer failpoint.Disable("tikvclient/injectTxnScope")
// set txn_scope to local
tk.MustExec("set @@session.txn_scope = 'local';")
result = tk.MustQuery("select @@txn_scope;")
result.Check(testkit.Rows("local"))
// test local txn auto commit
tk.MustExec("insert into t1 (c) values (1)") // write dc-1 with dc-1 scope
result = tk.MustQuery("select * from t1 where c = 1") // point get dc-1 with dc-1 scope
require.Equal(t, 3, len(result.Rows()))
result = tk.MustQuery("select * from t1 where c < 100") // read dc-1 with dc-1 scope
require.Equal(t, 3, len(result.Rows()))
// begin and commit with dc-1 txn scope
tk.MustExec("begin")
txn, err = tk.Session().Txn(true)
require.NoError(t, err)
require.Equal(t, "dc-1", tk.Session().GetSessionVars().CheckAndGetTxnScope())
require.True(t, txn.Valid())
tk.MustExec("insert into t1 (c) values (1)") // write dc-1 with dc-1 scope
result = tk.MustQuery("select * from t1 where c < 100") // read dc-1 with dc-1 scope
require.Equal(t, 4, len(result.Rows()))
require.True(t, txn.Valid())
tk.MustExec("commit")
result = tk.MustQuery("select * from t1 where c < 100")
require.Equal(t, 4, len(result.Rows()))
// begin and rollback with dc-1 txn scope
tk.MustExec("begin")
txn, err = tk.Session().Txn(true)
require.NoError(t, err)
require.Equal(t, "dc-1", tk.Session().GetSessionVars().CheckAndGetTxnScope())
require.True(t, txn.Valid())
tk.MustExec("insert into t1 (c) values (1)") // write dc-1 with dc-1 scope
result = tk.MustQuery("select * from t1 where c < 100") // read dc-1 with dc-1 scope
require.Equal(t, 5, len(result.Rows()))
require.True(t, txn.Valid())
tk.MustExec("rollback")
result = tk.MustQuery("select * from t1 where c < 100")
require.Equal(t, 4, len(result.Rows()))
// test wrong scope local txn auto commit
_, err = tk.Exec("insert into t1 (c) values (101)") // write dc-2 with dc-1 scope
require.Error(t, err)
require.Regexp(t, ".*out of txn_scope.*", err)
err = tk.ExecToErr("select * from t1 where c = 101") // point get dc-2 with dc-1 scope
require.Error(t, err)
require.Regexp(t, ".*can not be read by.*", err)
err = tk.ExecToErr("select * from t1 where c > 100") // read dc-2 with dc-1 scope
require.Error(t, err)
require.Regexp(t, ".*can not be read by.*", err)
tk.MustExec("begin")
err = tk.ExecToErr("select * from t1 where c = 101") // point get dc-2 with dc-1 scope
require.Error(t, err)
require.Regexp(t, ".*can not be read by.*", err)
err = tk.ExecToErr("select * from t1 where c > 100") // read dc-2 with dc-1 scope
require.Error(t, err)
require.Regexp(t, ".*can not be read by.*", err)
tk.MustExec("commit")
// begin and commit reading & writing the data in dc-2 with dc-1 txn scope
tk.MustExec("begin")
txn, err = tk.Session().Txn(true)
require.NoError(t, err)
require.Equal(t, "dc-1", tk.Session().GetSessionVars().CheckAndGetTxnScope())
require.True(t, txn.Valid())
tk.MustExec("insert into t1 (c) values (101)") // write dc-2 with dc-1 scope
err = tk.ExecToErr("select * from t1 where c > 100") // read dc-2 with dc-1 scope
require.Error(t, err)
require.Regexp(t, ".*can not be read by.*", err)
tk.MustExec("insert into t1 (c) values (99)") // write dc-1 with dc-1 scope
result = tk.MustQuery("select * from t1 where c < 100") // read dc-1 with dc-1 scope
require.Equal(t, 5, len(result.Rows()))
require.True(t, txn.Valid())
_, err = tk.Exec("commit")
require.Error(t, err)
require.Regexp(t, ".*out of txn_scope.*", err)
// Won't read the value 99 because the previous commit failed
result = tk.MustQuery("select * from t1 where c < 100") // read dc-1 with dc-1 scope
require.Equal(t, 4, len(result.Rows()))
// Stale Read will ignore the cross-dc txn scope.
require.Equal(t, "dc-1", tk.Session().GetSessionVars().CheckAndGetTxnScope())
result = tk.MustQuery("select @@txn_scope;")
result.Check(testkit.Rows("local"))
err = tk.ExecToErr("select * from t1 where c > 100") // read dc-2 with dc-1 scope
require.Error(t, err)
require.Regexp(t, ".*can not be read by.*", err)
// Read dc-2 with Stale Read (in dc-1 scope)
timestamp := timeBeforeWriting.Format(time.RFC3339Nano)
// TODO: check the result of Stale Read when we figure out how to make the time precision more accurate.
tk.MustExec(fmt.Sprintf("select * from t1 AS OF TIMESTAMP '%s' where c = 101", timestamp))
tk.MustExec(fmt.Sprintf("select * from t1 AS OF TIMESTAMP '%s' where c > 100", timestamp))
tk.MustExec(fmt.Sprintf("START TRANSACTION READ ONLY AS OF TIMESTAMP '%s'", timestamp))
tk.MustExec("select * from t1 where c = 101")
tk.MustExec("select * from t1 where c > 100")
tk.MustExec("commit")
tk.MustExec("set @@tidb_replica_read='closest-replicas'")
tk.MustExec(fmt.Sprintf("select * from t1 AS OF TIMESTAMP '%s' where c > 100", timestamp))
tk.MustExec(fmt.Sprintf("START TRANSACTION READ ONLY AS OF TIMESTAMP '%s'", timestamp))
tk.MustExec("select * from t1 where c = 101")
tk.MustExec("select * from t1 where c > 100")
tk.MustExec("commit")
tk.MustExec("set global tidb_enable_local_txn = off;")
}