sessionctx: add variable tidb_analyze_version

session/session.go

@@ -2288,6 +2288,7 @@ var builtinGlobalVariable = []string{
 	variable.TiDBEnableAsyncCommit,
 	variable.TiDBEnable1PC,
 	variable.TiDBGuaranteeExternalConsistency,
+	variable.TiDBAnalyzeVersion,
 }
 
 var (

sessionctx/variable/session.go

@@ -761,6 +761,9 @@ type SessionVars struct {
 	Enable1PC bool
 
 	GuaranteeExternalConsistency bool
+
+	// AnalyzeVersion indicates how TiDB collect and use analyzed statistics.
+	AnalyzeVersion int
 }
 
 // CheckAndGetTxnScope will return the transaction scope we should use in the current session.
@@ -911,6 +914,7 @@ func NewSessionVars() *SessionVars {
 		EnableAsyncCommit:            DefTiDBEnableAsyncCommit,
 		Enable1PC:                    DefTiDBEnable1PC,
 		GuaranteeExternalConsistency: DefTiDBGuaranteeExternalConsistency,
+		AnalyzeVersion:               DefTiDBAnalyzeVersion,
 	}
 	vars.KVVars = kv.NewVariables(&vars.Killed)
 	vars.Concurrency = Concurrency{
@@ -1627,6 +1631,8 @@ func (s *SessionVars) SetSystemVar(name string, val string) error {
 		s.Enable1PC = TiDBOptOn(val)
 	case TiDBGuaranteeExternalConsistency:
 		s.GuaranteeExternalConsistency = TiDBOptOn(val)
+	case TiDBAnalyzeVersion:
+		s.AnalyzeVersion = tidbOptPositiveInt32(val, DefTiDBAnalyzeVersion)
 	}
 	s.systems[name] = val
 	return nil

sessionctx/variable/sysvar.go

@@ -1156,6 +1156,7 @@ var defaultSysVars = []*SysVar{
 	{Scope: ScopeGlobal | ScopeSession, Name: TiDBEnableAsyncCommit, Value: BoolToOnOff(DefTiDBEnableAsyncCommit), Type: TypeBool},
 	{Scope: ScopeGlobal | ScopeSession, Name: TiDBEnable1PC, Value: BoolToOnOff(DefTiDBEnable1PC), Type: TypeBool},
 	{Scope: ScopeGlobal | ScopeSession, Name: TiDBGuaranteeExternalConsistency, Value: BoolToOnOff(DefTiDBGuaranteeExternalConsistency), Type: TypeBool},
+	{Scope: ScopeGlobal | ScopeSession, Name: TiDBAnalyzeVersion, Value: strconv.Itoa(DefTiDBAnalyzeVersion), Type: TypeInt, MinValue: 1, MaxValue: 1},
 }
 
 // SynonymsSysVariables is synonyms of system variables.

sessionctx/variable/tidb_vars.go

@@ -485,6 +485,9 @@ const (
 
 	// TiDBGuaranteeExternalConsistency indicates whether maintain the external consistency.
 	TiDBGuaranteeExternalConsistency = "tidb_guarantee_external_consistency"
+
+	// TiDBAnalyzeVersion indicates the how tidb collects the analyzed statistics and how use to it.
+	TiDBAnalyzeVersion = "tidb_analyze_version"
 )
 
 // Default TiDB system variable values.
@@ -601,6 +604,7 @@ const (
 	DefTiDBEnableAsyncCommit            = false
 	DefTiDBEnable1PC                    = false
 	DefTiDBGuaranteeExternalConsistency = false
+	DefTiDBAnalyzeVersion               = 1
 )
 
 // Process global variables.

sessionctx/variable/varsutil_test.go

@@ -105,6 +105,7 @@ func (s *testVarsutilSuite) TestNewSessionVars(c *C) {
 	c.Assert(vars.AllowAutoRandExplicitInsert, Equals, DefTiDBAllowAutoRandExplicitInsert)
 	c.Assert(vars.ShardAllocateStep, Equals, int64(DefTiDBShardAllocateStep))
 	c.Assert(vars.EnableChangeColumnType, Equals, DefTiDBChangeColumnType)
+	c.Assert(vars.AnalyzeVersion, Equals, DefTiDBAnalyzeVersion)
 
 	assertFieldsGreaterThanZero(c, reflect.ValueOf(vars.MemQuota))
 	assertFieldsGreaterThanZero(c, reflect.ValueOf(vars.BatchSize))
@@ -488,6 +489,9 @@ func (s *testVarsutilSuite) TestVarsutil(c *C) {
 
 	err = SetSessionSystemVar(v, "UnknownVariable", types.NewStringDatum("on"))
 	c.Assert(err, ErrorMatches, ".*]Unknown system variable 'UnknownVariable'")
+
+	err = SetSessionSystemVar(v, TiDBAnalyzeVersion, types.NewStringDatum("3"))
+	c.Assert(err, ErrorMatches, ".*Variable 'tidb_analyze_version' can't be set to the value of '3'")
 }
 
 func (s *testVarsutilSuite) TestSetOverflowBehave(c *C) {