sessionctx: support fast analyze session control variable. (#10039)

session/session.go

@@ -1537,6 +1537,7 @@ var builtinGlobalVariable = []string{
 	variable.TiDBRetryLimit,
 	variable.TiDBDisableTxnAutoRetry,
 	variable.TiDBEnableWindowFunction,
+	variable.TiDBEnableFastAnalyze,
 }
 
 var (

sessionctx/variable/session.go

@@ -340,6 +340,9 @@ type SessionVars struct {
 
 	// SlowQueryFile indicates which slow query log file for SLOW_QUERY table to parse.
 	SlowQueryFile string
+
+	// EnableFastAnalyze indicates whether to take fast analyze.
+	EnableFastAnalyze bool
 }
 
 // ConnectionInfo present connection used by audit.
@@ -725,6 +728,8 @@ func (s *SessionVars) SetSystemVar(name string, val string) error {
 		config.GetGlobalConfig().CheckMb4ValueInUTF8 = TiDBOptOn(val)
 	case TiDBSlowQueryFile:
 		s.SlowQueryFile = val
+	case TiDBEnableFastAnalyze:
+		s.EnableFastAnalyze = TiDBOptOn(val)
 	}
 	s.systems[name] = val
 	return nil

sessionctx/variable/sysvar.go

@@ -672,6 +672,7 @@ var defaultSysVars = []*SysVar{
 	{ScopeGlobal | ScopeSession, TiDBConstraintCheckInPlace, BoolToIntStr(DefTiDBConstraintCheckInPlace)},
 	{ScopeSession, TiDBOptimizerSelectivityLevel, strconv.Itoa(DefTiDBOptimizerSelectivityLevel)},
 	{ScopeGlobal | ScopeSession, TiDBEnableWindowFunction, BoolToIntStr(DefEnableWindowFunction)},
+	{ScopeGlobal | ScopeSession, TiDBEnableFastAnalyze, BoolToIntStr(DefTiDBUseFastAnalyze)},
 	/* The following variable is defined as session scope but is actually server scope. */
 	{ScopeSession, TiDBGeneralLog, strconv.Itoa(DefTiDBGeneralLog)},
 	{ScopeSession, TiDBSlowLogThreshold, strconv.Itoa(logutil.DefaultSlowThreshold)},

sessionctx/variable/tidb_vars.go

@@ -239,6 +239,9 @@ const (
 
 	// SlowQueryFile indicates which slow query log file for SLOW_QUERY table to parse.
 	TiDBSlowQueryFile = "tidb_slow_query_file"
+
+	// TiDBEnableFastAnalyze indicates to use fast analyze.
+	TiDBEnableFastAnalyze = "tidb_enable_fast_analyze"
 )
 
 // Default TiDB system variable values.
@@ -291,6 +294,7 @@ const (
 	DefTiDBUseRadixJoin              = false
 	DefEnableWindowFunction          = false
 	DefTiDBDDLSlowOprThreshold       = 300
+	DefTiDBUseFastAnalyze            = false
 )
 
 // Process global variables.

sessionctx/variable/varsutil.go

@@ -359,7 +359,7 @@ func ValidateSetSystemVar(vars *SessionVars, name string, value string) (string,
 		}
 		return value, ErrWrongValueForVar.GenWithStackByArgs(name, value)
 	case AutocommitVar, TiDBSkipUTF8Check, TiDBOptAggPushDown,
-		TiDBOptInSubqToJoinAndAgg,
+		TiDBOptInSubqToJoinAndAgg, TiDBEnableFastAnalyze,
 		TiDBBatchInsert, TiDBDisableTxnAutoRetry, TiDBEnableStreaming,
 		TiDBBatchDelete, TiDBBatchCommit, TiDBEnableCascadesPlanner, TiDBEnableWindowFunction,
 		TiDBCheckMb4ValueInUTF8:

sessionctx/variable/varsutil_test.go

@@ -79,6 +79,7 @@ func (s *testVarsutilSuite) TestNewSessionVars(c *C) {
 	c.Assert(vars.MemQuotaNestedLoopApply, Equals, int64(DefTiDBMemQuotaNestedLoopApply))
 	c.Assert(vars.EnableRadixJoin, Equals, DefTiDBUseRadixJoin)
 	c.Assert(vars.AllowWriteRowID, Equals, DefOptWriteRowID)
+	c.Assert(vars.EnableFastAnalyze, Equals, DefTiDBUseFastAnalyze)
 
 	assertFieldsGreaterThanZero(c, reflect.ValueOf(vars.Concurrency))
 	assertFieldsGreaterThanZero(c, reflect.ValueOf(vars.MemQuota))