txn: tidb_constraint_check_in_place_pessimistic should not be global …

…scoped (#38767)

close #38766

config/config.go

@@ -751,6 +751,8 @@ type PessimisticTxn struct {
 	DeadlockHistoryCollectRetryable bool `toml:"deadlock-history-collect-retryable" json:"deadlock-history-collect-retryable"`
 	// PessimisticAutoCommit represents if true it means the auto-commit transactions will be in pessimistic mode.
 	PessimisticAutoCommit AtomicBool `toml:"pessimistic-auto-commit" json:"pessimistic-auto-commit"`
+	// ConstraintCheckInPlacePessimistic is the default value for the session variable `tidb_constraint_check_in_place_pessimistic`
+	ConstraintCheckInPlacePessimistic bool `toml:"constraint-check-in-place-pessimistic" json:"constraint-check-in-place-pessimistic"`
 }
 
 // TrxSummary is the config for transaction summary collecting.
@@ -772,10 +774,11 @@ func (config *TrxSummary) Valid() error {
 // DefaultPessimisticTxn returns the default configuration for PessimisticTxn
 func DefaultPessimisticTxn() PessimisticTxn {
 	return PessimisticTxn{
-		MaxRetryCount:                   256,
-		DeadlockHistoryCapacity:         10,
-		DeadlockHistoryCollectRetryable: false,
-		PessimisticAutoCommit:           *NewAtomicBool(false),
+		MaxRetryCount:                     256,
+		DeadlockHistoryCapacity:           10,
+		DeadlockHistoryCollectRetryable:   false,
+		PessimisticAutoCommit:             *NewAtomicBool(false),
+		ConstraintCheckInPlacePessimistic: true,
 	}
 }
 
@@ -1040,7 +1043,7 @@ var removedConfig = map[string]struct{}{
 	"log.query-log-max-len":              {},
 	"performance.committer-concurrency":  {},
 	"experimental.enable-global-kill":    {},
-	"performance.run-auto-analyze":       {}, //use tidb_enable_auto_analyze
+	"performance.run-auto-analyze":       {}, // use tidb_enable_auto_analyze
 	// use tidb_enable_prepared_plan_cache, tidb_prepared_plan_cache_size and tidb_prepared_plan_cache_memory_guard_ratio
 	"prepared-plan-cache.enabled":            {},
 	"prepared-plan-cache.capacity":           {},

metrics/session.go

@@ -166,7 +166,7 @@ var (
 			Namespace: "tidb",
 			Subsystem: "session",
 			Name:      "lazy_pessimistic_unique_check_set_count",
-			Help:      "Counter of setting tidb_constraint_check_in_place to false",
+			Help:      "Counter of setting tidb_constraint_check_in_place to false, note that it doesn't count the default value set by tidb config",
 		},
 	)
 )

session/session.go

@@ -1352,6 +1352,10 @@ func createSessionFunc(store kv.Storage) pools.Factory {
 		if err != nil {
 			return nil, errors.Trace(err)
 		}
+		err = se.sessionVars.SetSystemVar(variable.TiDBConstraintCheckInPlacePessimistic, variable.On)
+		if err != nil {
+			return nil, errors.Trace(err)
+		}
 		se.sessionVars.CommonGlobalLoaded = true
 		se.sessionVars.InRestrictedSQL = true
 		// Internal session uses default format to prevent memory leak problem.
@@ -1378,6 +1382,10 @@ func createSessionWithDomainFunc(store kv.Storage) func(*domain.Domain) (pools.R
 		if err != nil {
 			return nil, errors.Trace(err)
 		}
+		err = se.sessionVars.SetSystemVar(variable.TiDBConstraintCheckInPlacePessimistic, variable.On)
+		if err != nil {
+			return nil, errors.Trace(err)
+		}
 		se.sessionVars.CommonGlobalLoaded = true
 		se.sessionVars.InRestrictedSQL = true
 		// Internal session uses default format to prevent memory leak problem.

sessionctx/variable/sysvar.go

@@ -1929,7 +1929,7 @@ var defaultSysVars = []*SysVar{
 		DDLDiskQuota.Store(TidbOptUint64(val, DefTiDBDDLDiskQuota))
 		return nil
 	}},
-	{Scope: ScopeGlobal | ScopeSession, Name: TiDBConstraintCheckInPlacePessimistic, Value: BoolToOnOff(DefTiDBConstraintCheckInPlacePessimistic), Type: TypeBool,
+	{Scope: ScopeSession, Name: TiDBConstraintCheckInPlacePessimistic, Value: BoolToOnOff(config.GetGlobalConfig().PessimisticTxn.ConstraintCheckInPlacePessimistic), Type: TypeBool,
 		SetSession: func(s *SessionVars, val string) error {
 			s.ConstraintCheckInPlacePessimistic = TiDBOptOn(val)
 			if !s.ConstraintCheckInPlacePessimistic {

sessionctx/variable/tidb_vars.go

@@ -1070,19 +1070,18 @@ const (
 	DefTiDBGeneralPlanCacheSize                    = 100
 	DefTiDBEnableTiFlashReadForWriteStmt           = false
 	// MaxDDLReorgBatchSize is exported for testing.
-	MaxDDLReorgBatchSize                     int32  = 10240
-	MinDDLReorgBatchSize                     int32  = 32
-	MinExpensiveQueryTimeThreshold           uint64 = 10 // 10s
-	DefTiDBRcWriteCheckTs                           = false
-	DefTiDBConstraintCheckInPlacePessimistic        = true
-	DefTiDBForeignKeyChecks                         = false
-	DefTiDBAnalyzePartitionConcurrency              = 1
-	DefTiDBOptRangeMaxSize                          = 64 * int64(size.MB) // 64 MB
-	DefTiDBCostModelVer                             = 1
-	DefTiDBServerMemoryLimitSessMinSize             = 128 << 20
-	DefTiDBMergePartitionStatsConcurrency           = 1
-	DefTiDBServerMemoryLimitGCTrigger               = 0.7
-	DefTiDBEnableGOGCTuner                          = true
+	MaxDDLReorgBatchSize                  int32  = 10240
+	MinDDLReorgBatchSize                  int32  = 32
+	MinExpensiveQueryTimeThreshold        uint64 = 10 // 10s
+	DefTiDBRcWriteCheckTs                        = false
+	DefTiDBForeignKeyChecks                      = false
+	DefTiDBAnalyzePartitionConcurrency           = 1
+	DefTiDBOptRangeMaxSize                       = 64 * int64(size.MB) // 64 MB
+	DefTiDBCostModelVer                          = 1
+	DefTiDBServerMemoryLimitSessMinSize          = 128 << 20
+	DefTiDBMergePartitionStatsConcurrency        = 1
+	DefTiDBServerMemoryLimitGCTrigger            = 0.7
+	DefTiDBEnableGOGCTuner                       = true
 	// DefTiDBGOGCTunerThreshold is to limit TiDBGOGCTunerThreshold.
 	DefTiDBGOGCTunerThreshold       float64 = 0.6
 	DefTiDBOptPrefixIndexSingleScan         = true

table/tables/index.go

@@ -229,7 +229,8 @@ func (c *index) Create(sctx sessionctx.Context, txn kv.Transaction, indexedValue
 		}
 		if lazyCheck {
 			flags := []kv.FlagsOp{kv.SetPresumeKeyNotExists}
-			if !vars.ConstraintCheckInPlacePessimistic && vars.TxnCtx.IsPessimistic && vars.InTxn() {
+			if !vars.ConstraintCheckInPlacePessimistic && vars.TxnCtx.IsPessimistic && vars.InTxn() &&
+				!vars.InRestrictedSQL && vars.ConnectionID > 0 {
 				flags = append(flags, kv.SetNeedConstraintCheckInPrewrite)
 			}
 			err = txn.GetMemBuffer().SetWithFlags(key, idxVal, flags...)

table/tables/tables.go

@@ -854,7 +854,8 @@ func (t *TableCommon) AddRecord(sctx sessionctx.Context, r []types.Datum, opts .
 
 	if setPresume {
 		flags := []kv.FlagsOp{kv.SetPresumeKeyNotExists}
-		if !sessVars.ConstraintCheckInPlacePessimistic && sessVars.TxnCtx.IsPessimistic && sessVars.InTxn() {
+		if !sessVars.ConstraintCheckInPlacePessimistic && sessVars.TxnCtx.IsPessimistic && sessVars.InTxn() &&
+			!sessVars.InRestrictedSQL && sessVars.ConnectionID > 0 {
 			flags = append(flags, kv.SetNeedConstraintCheckInPrewrite)
 		}
 		err = memBuffer.SetWithFlags(key, value, flags...)

tidb-server/main.go

@@ -671,6 +671,7 @@ func setGlobalVars() {
 	variable.SetSysVar(variable.TiDBIsolationReadEngines, strings.Join(cfg.IsolationRead.Engines, ","))
 	variable.SetSysVar(variable.TiDBEnforceMPPExecution, variable.BoolToOnOff(config.GetGlobalConfig().Performance.EnforceMPP))
 	variable.MemoryUsageAlarmRatio.Store(cfg.Instance.MemoryUsageAlarmRatio)
+	variable.SetSysVar(variable.TiDBConstraintCheckInPlacePessimistic, variable.BoolToOnOff(cfg.PessimisticTxn.ConstraintCheckInPlacePessimistic))
 	if hostname, err := os.Hostname(); err == nil {
 		variable.SetSysVar(variable.Hostname, hostname)
 	}