sessionctx/variable, ddl: fix sysvar API usage (pingcap#35052)

ref pingcap#35051
xmuyoo · Jun 6, 2022 · 233a733 · 233a733
1 parent 45a6758
commit 233a733
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Showing 6 changed files with 20 additions and 27 deletions.
diff --git a/ddl/ddl_api.go b/ddl/ddl_api.go
@@ -2994,7 +2994,7 @@ func isSameTypeMultiSpecs(specs []*ast.AlterTableSpec) bool {
 }
 
 func checkMultiSpecs(sctx sessionctx.Context, specs []*ast.AlterTableSpec) error {
-	if !sctx.GetSessionVars().EnableChangeMultiSchema {
+	if !variable.EnableChangeMultiSchema.Load() {
 		if len(specs) > 1 {
 			return dbterror.ErrRunMultiSchemaChanges
 		}
@@ -4023,7 +4023,7 @@ func (d *ddl) DropColumn(ctx sessionctx.Context, ti ast.Ident, spec *ast.AlterTa
 		return err
 	}
 	var multiSchemaInfo *model.MultiSchemaInfo
-	if ctx.GetSessionVars().EnableChangeMultiSchema {
+	if variable.EnableChangeMultiSchema.Load() {
 		multiSchemaInfo = &model.MultiSchemaInfo{}
 	}
 
@@ -4102,7 +4102,7 @@ func (d *ddl) DropColumns(ctx sessionctx.Context, ti ast.Ident, specs []*ast.Alt
 		return err
 	}
 	var multiSchemaInfo *model.MultiSchemaInfo
-	if ctx.GetSessionVars().EnableChangeMultiSchema {
+	if variable.EnableChangeMultiSchema.Load() {
 		multiSchemaInfo = &model.MultiSchemaInfo{}
 	}
 
@@ -4139,7 +4139,7 @@ func checkIsDroppableColumn(ctx sessionctx.Context, t table.Table, spec *ast.Alt
 		return false, err
 	}
 
-	if err = isDroppableColumn(ctx.GetSessionVars().EnableChangeMultiSchema, tblInfo, colName); err != nil {
+	if err = isDroppableColumn(variable.EnableChangeMultiSchema.Load(), tblInfo, colName); err != nil {
 		return false, errors.Trace(err)
 	}
 	// We don't support dropping column with PK handle covered now.

diff --git a/sessionctx/variable/session.go b/sessionctx/variable/session.go
@@ -837,9 +837,6 @@ type SessionVars struct {
 	// DDLReorgPriority is the operation priority of adding indices.
 	DDLReorgPriority int
 
-	// EnableChangeMultiSchema is used to control whether to enable the multi schema change.
-	EnableChangeMultiSchema bool
-
 	// EnableAutoIncrementInGenerated is used to control whether to allow auto incremented columns in generated columns.
 	EnableAutoIncrementInGenerated bool
 
@@ -1348,7 +1345,6 @@ func NewSessionVars() *SessionVars {
 		EnableClusteredIndex:        DefTiDBEnableClusteredIndex,
 		EnableParallelApply:         DefTiDBEnableParallelApply,
 		ShardAllocateStep:           DefTiDBShardAllocateStep,
-		EnableChangeMultiSchema:     DefTiDBChangeMultiSchema,
 		EnablePointGetCache:         DefTiDBPointGetCache,
 		EnableAmendPessimisticTxn:   DefTiDBEnableAmendPessimisticTxn,
 		PartitionPruneMode:          *atomic2.NewString(DefTiDBPartitionPruneMode),

diff --git a/sessionctx/variable/sysvar.go b/sessionctx/variable/sysvar.go
@@ -465,33 +465,34 @@ var defaultSysVars = []*SysVar{
 		SetDDLReorgRowFormat(TidbOptInt64(val, DefTiDBRowFormatV2))
 		return nil
 	}},
-	{Scope: ScopeGlobal, Name: TiDBDDLReorgWorkerCount, Value: strconv.Itoa(DefTiDBDDLReorgWorkerCount), Type: TypeUnsigned, MinValue: 1, MaxValue: MaxConfigurableConcurrency, SetSession: func(s *SessionVars, val string) error {
+	{Scope: ScopeGlobal, Name: TiDBDDLReorgWorkerCount, Value: strconv.Itoa(DefTiDBDDLReorgWorkerCount), Type: TypeUnsigned, MinValue: 1, MaxValue: MaxConfigurableConcurrency, SetGlobal: func(s *SessionVars, val string) error {
 		SetDDLReorgWorkerCounter(int32(tidbOptPositiveInt32(val, DefTiDBDDLReorgWorkerCount)))
 		return nil
 	}},
-	{Scope: ScopeGlobal, Name: TiDBDDLReorgBatchSize, Value: strconv.Itoa(DefTiDBDDLReorgBatchSize), Type: TypeUnsigned, MinValue: int64(MinDDLReorgBatchSize), MaxValue: uint64(MaxDDLReorgBatchSize), SetSession: func(s *SessionVars, val string) error {
+	{Scope: ScopeGlobal, Name: TiDBDDLReorgBatchSize, Value: strconv.Itoa(DefTiDBDDLReorgBatchSize), Type: TypeUnsigned, MinValue: int64(MinDDLReorgBatchSize), MaxValue: uint64(MaxDDLReorgBatchSize), SetGlobal: func(s *SessionVars, val string) error {
 		SetDDLReorgBatchSize(int32(tidbOptPositiveInt32(val, DefTiDBDDLReorgBatchSize)))
 		return nil
 	}},
-	{Scope: ScopeGlobal, Name: TiDBDDLErrorCountLimit, Value: strconv.Itoa(DefTiDBDDLErrorCountLimit), Type: TypeUnsigned, MinValue: 0, MaxValue: math.MaxInt64, SetSession: func(s *SessionVars, val string) error {
+	{Scope: ScopeGlobal, Name: TiDBDDLErrorCountLimit, Value: strconv.Itoa(DefTiDBDDLErrorCountLimit), Type: TypeUnsigned, MinValue: 0, MaxValue: math.MaxInt64, SetGlobal: func(s *SessionVars, val string) error {
 		SetDDLErrorCountLimit(TidbOptInt64(val, DefTiDBDDLErrorCountLimit))
 		return nil
 	}},
-	{Scope: ScopeGlobal, Name: TiDBMaxDeltaSchemaCount, Value: strconv.Itoa(DefTiDBMaxDeltaSchemaCount), Type: TypeUnsigned, MinValue: 100, MaxValue: 16384, SetSession: func(s *SessionVars, val string) error {
+	{Scope: ScopeGlobal, Name: TiDBMaxDeltaSchemaCount, Value: strconv.Itoa(DefTiDBMaxDeltaSchemaCount), Type: TypeUnsigned, MinValue: 100, MaxValue: 16384, SetGlobal: func(s *SessionVars, val string) error {
 		// It's a global variable, but it also wants to be cached in server.
 		SetMaxDeltaSchemaCount(TidbOptInt64(val, DefTiDBMaxDeltaSchemaCount))
 		return nil
 	}},
-	{Scope: ScopeGlobal, Name: TiDBEnableChangeMultiSchema, Value: BoolToOnOff(DefTiDBChangeMultiSchema), Hidden: true, Type: TypeBool, SetSession: func(s *SessionVars, val string) error {
-		s.EnableChangeMultiSchema = TiDBOptOn(val)
-		return nil
-	}, SetGlobal: func(s *SessionVars, val string) error {
-		s.EnableChangeMultiSchema = TiDBOptOn(val)
+	{Scope: ScopeGlobal, Name: TiDBEnableChangeMultiSchema, Value: BoolToOnOff(DefTiDBChangeMultiSchema), Hidden: true, Type: TypeBool, SetGlobal: func(s *SessionVars, val string) error {
+		EnableChangeMultiSchema.Store(TiDBOptOn(val))
 		return nil
+	}, GetGlobal: func(s *SessionVars) (string, error) {
+		return BoolToOnOff(EnableChangeMultiSchema.Load()), nil
 	}},
-	{Scope: ScopeGlobal, Name: TiDBEnablePointGetCache, Value: BoolToOnOff(DefTiDBPointGetCache), Hidden: true, Type: TypeBool, SetSession: func(s *SessionVars, val string) error {
-		s.EnablePointGetCache = TiDBOptOn(val)
+	{Scope: ScopeGlobal, Name: TiDBEnablePointGetCache, Value: BoolToOnOff(DefTiDBPointGetCache), Hidden: true, Type: TypeBool, SetGlobal: func(s *SessionVars, val string) error {
+		EnablePointGetCache.Store(TiDBOptOn(val))
 		return nil
+	}, GetGlobal: func(s *SessionVars) (string, error) {
+		return BoolToOnOff(EnablePointGetCache.Load()), nil
 	}},
 	{Scope: ScopeGlobal, Name: TiDBScatterRegion, Value: BoolToOnOff(DefTiDBScatterRegion), Type: TypeBool},
 	{Scope: ScopeGlobal, Name: TiDBEnableStmtSummary, Value: BoolToOnOff(DefTiDBEnableStmtSummary), Type: TypeBool, AllowEmpty: true,

diff --git a/sessionctx/variable/sysvar_test.go b/sessionctx/variable/sysvar_test.go
@@ -656,10 +656,7 @@ func TestSettersandGetters(t *testing.T) {
 			// There are some historial exceptions where global variables are loaded into the session.
 			// Please don't add to this list, the behavior is not MySQL compatible.
 			switch sv.Name {
-			case TiDBEnableChangeMultiSchema, TiDBDDLReorgBatchSize,
-				TiDBMaxDeltaSchemaCount, InitConnect, MaxPreparedStmtCount,
-				TiDBDDLReorgWorkerCount, TiDBDDLErrorCountLimit, TiDBRowFormatVersion,
-				TiDBEnableTelemetry, TiDBEnablePointGetCache:
+			case TiDBRowFormatVersion:
 				continue
 			}
 			require.Nil(t, sv.SetSession)

diff --git a/sessionctx/variable/tidb_vars.go b/sessionctx/variable/tidb_vars.go
@@ -919,6 +919,8 @@ var (
 	DefExecutorConcurrency                = 5
 	MemoryUsageAlarmRatio                 = atomic.NewFloat64(config.GetGlobalConfig().Instance.MemoryUsageAlarmRatio)
 	EnableLocalTxn                        = atomic.NewBool(DefTiDBEnableLocalTxn)
+	EnablePointGetCache                   = atomic.NewBool(DefTiDBPointGetCache)
+	EnableChangeMultiSchema               = atomic.NewBool(DefTiDBChangeMultiSchema)
 	MaxTSOBatchWaitInterval               = atomic.NewFloat64(DefTiDBTSOClientBatchMaxWaitTime)
 	EnableTSOFollowerProxy                = atomic.NewBool(DefTiDBEnableTSOFollowerProxy)
 	RestrictedReadOnly                    = atomic.NewBool(DefTiDBRestrictedReadOnly)

diff --git a/sessionctx/variable/variable.go b/sessionctx/variable/variable.go
@@ -516,10 +516,7 @@ func (sv *SysVar) SkipInit() bool {
 	// These a special "Global-only" sysvars that for backward compatibility
 	// are currently cached in the session. Please don't add to this list.
 	switch sv.Name {
-	case TiDBEnableChangeMultiSchema, TiDBDDLReorgBatchSize,
-		TiDBMaxDeltaSchemaCount, InitConnect, MaxPreparedStmtCount,
-		TiDBDDLReorgWorkerCount, TiDBDDLErrorCountLimit, TiDBRowFormatVersion,
-		TiDBEnableTelemetry, TiDBEnablePointGetCache:
+	case TiDBRowFormatVersion:
 		return false
 	}
 	return !sv.HasSessionScope()