variable: raise the upper limit of tidb_analyze_distsql_scan_concurre…

…ncy (pingcap#50529)

close pingcap#50528

pkg/sessionctx/variable/sysvar.go

@@ -1320,7 +1320,7 @@ var defaultSysVars = []*SysVar{
 		return BoolToOnOff(EnableTmpStorageOnOOM.Load()), nil
 	}},
 	{Scope: ScopeGlobal, Name: TiDBAutoBuildStatsConcurrency, Value: strconv.Itoa(DefTiDBAutoBuildStatsConcurrency), Type: TypeInt, MinValue: 1, MaxValue: MaxConfigurableConcurrency},
-	{Scope: ScopeGlobal, Name: TiDBSysProcScanConcurrency, Value: strconv.Itoa(DefTiDBSysProcScanConcurrency), Type: TypeInt, MinValue: 1, MaxValue: MaxConfigurableConcurrency},
+	{Scope: ScopeGlobal, Name: TiDBSysProcScanConcurrency, Value: strconv.Itoa(DefTiDBSysProcScanConcurrency), Type: TypeInt, MinValue: 1, MaxValue: math.MaxInt32},
 	{Scope: ScopeGlobal, Name: TiDBMemoryUsageAlarmRatio, Value: strconv.FormatFloat(DefMemoryUsageAlarmRatio, 'f', -1, 64), Type: TypeFloat, MinValue: 0.0, MaxValue: 1.0, SetGlobal: func(_ context.Context, s *SessionVars, val string) error {
 		MemoryUsageAlarmRatio.Store(tidbOptFloat64(val, DefMemoryUsageAlarmRatio))
 		return nil
@@ -1695,7 +1695,7 @@ var defaultSysVars = []*SysVar{
 		s.distSQLScanConcurrency = tidbOptPositiveInt32(val, DefDistSQLScanConcurrency)
 		return nil
 	}},
-	{Scope: ScopeGlobal | ScopeSession, Name: TiDBAnalyzeDistSQLScanConcurrency, Value: strconv.Itoa(DefAnalyzeDistSQLScanConcurrency), Type: TypeUnsigned, MinValue: 1, MaxValue: MaxConfigurableConcurrency, SetSession: func(s *SessionVars, val string) error {
+	{Scope: ScopeGlobal | ScopeSession, Name: TiDBAnalyzeDistSQLScanConcurrency, Value: strconv.Itoa(DefAnalyzeDistSQLScanConcurrency), Type: TypeUnsigned, MinValue: 1, MaxValue: math.MaxInt32, SetSession: func(s *SessionVars, val string) error {
 		s.analyzeDistSQLScanConcurrency = tidbOptPositiveInt32(val, DefAnalyzeDistSQLScanConcurrency)
 		return nil
 	}},