*: remove non dry sysvar code (#38182)

close #33896

domain/BUILD.bazel

@@ -4,6 +4,7 @@ go_library(
     name = "domain",
     srcs = [
         "domain.go",
+        "domain_sysvars.go",
         "domainctx.go",
         "optimize_trace.go",
         "plan_replayer.go",

domain/domain.go

@@ -889,7 +889,7 @@ func NewDomain(store kv.Storage, ddlLease time.Duration, statsLease time.Duratio
 	do.expensiveQueryHandle = expensivequery.NewExpensiveQueryHandle(do.exit)
 	do.serverMemoryLimitHandle = servermemorylimit.NewServerMemoryLimitHandle(do.exit)
 	do.sysProcesses = SysProcesses{mu: &sync.RWMutex{}, procMap: make(map[uint64]sessionctx.Context)}
-	variable.SetStatsCacheCapacity.Store(do.SetStatsCacheCapacity)
+	do.initDomainSysVars()
 	return do
 }
 

domain/domain_sysvars.go

@@ -0,0 +1,76 @@
+// Copyright 2022 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package domain
+
+import (
+	"strconv"
+	"time"
+
+	"github.com/pingcap/tidb/sessionctx/variable"
+	"github.com/pingcap/tidb/util/logutil"
+	pd "github.com/tikv/pd/client"
+	"go.uber.org/zap"
+)
+
+// initDomainSysVars() is called when a domain is initialized.
+// These are special system variables which require the current domain.
+// They can not be SetGlobal functions in sessionctx/variable directly
+// because the domain is not available. Instead a noop func is specified,
+// which is overwritten here.
+func (do *Domain) initDomainSysVars() {
+	variable.SetStatsCacheCapacity.Store(do.setStatsCacheCapacity)
+	variable.SetPDClientDynamicOption = do.setPDClientDynamicOption
+}
+
+// setStatsCacheCapacity sets statsCache cap
+func (do *Domain) setStatsCacheCapacity(c int64) {
+	do.StatsHandle().SetStatsCacheCapacity(c)
+	logutil.BgLogger().Info("update stats cache capacity successfully", zap.Int64("capacity", c))
+}
+
+func (do *Domain) setPDClientDynamicOption(name, sVal string) {
+	switch name {
+	case variable.TiDBTSOClientBatchMaxWaitTime:
+		val, err := strconv.ParseFloat(sVal, 64)
+		if err != nil {
+			break
+		}
+		err = do.updatePDClient(pd.MaxTSOBatchWaitInterval, time.Duration(float64(time.Millisecond)*val))
+		if err != nil {
+			break
+		}
+		variable.MaxTSOBatchWaitInterval.Store(val)
+	case variable.TiDBEnableTSOFollowerProxy:
+		val := variable.TiDBOptOn(sVal)
+		err := do.updatePDClient(pd.EnableTSOFollowerProxy, val)
+		if err != nil {
+			break
+		}
+		variable.EnableTSOFollowerProxy.Store(val)
+	}
+}
+
+// updatePDClient is used to set the dynamic option into the PD client.
+func (do *Domain) updatePDClient(option pd.DynamicOption, val interface{}) error {
+	store, ok := do.store.(interface{ GetPDClient() pd.Client })
+	if !ok {
+		return nil
+	}
+	pdClient := store.GetPDClient()
+	if pdClient == nil {
+		return nil
+	}
+	return pdClient.UpdateOption(option, val)
+}

domain/sysvar_cache.go

@@ -17,16 +17,13 @@ package domain
 import (
 	"context"
 	"fmt"
-	"strconv"
 	"sync"
-	"time"
 
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/util/logutil"
 	"github.com/pingcap/tidb/util/sqlexec"
-	pd "github.com/tikv/pd/client"
 	"go.uber.org/zap"
 	"golang.org/x/exp/maps"
 )
@@ -153,11 +150,6 @@ func (do *Domain) rebuildSysVarCache(ctx sessionctx.Context) error {
 				}
 			}
 		}
-
-		// Some PD options need to be checked outside of the SetGlobal func.
-		// This is also done for the SET GLOBAL caller in executor/set.go,
-		// but here we check for other tidb instances.
-		do.checkPDClientDynamicOption(sv.Name, sVal)
 	}
 
 	logutil.BgLogger().Debug("rebuilding sysvar cache")
@@ -168,44 +160,3 @@ func (do *Domain) rebuildSysVarCache(ctx sessionctx.Context) error {
 	do.sysVarCache.global = newGlobalCache
 	return nil
 }
-
-func (do *Domain) checkPDClientDynamicOption(name, sVal string) {
-	switch name {
-	case variable.TiDBTSOClientBatchMaxWaitTime:
-		val, err := strconv.ParseFloat(sVal, 64)
-		if err != nil {
-			break
-		}
-		err = do.SetPDClientDynamicOption(pd.MaxTSOBatchWaitInterval, time.Duration(float64(time.Millisecond)*val))
-		if err != nil {
-			break
-		}
-		variable.MaxTSOBatchWaitInterval.Store(val)
-	case variable.TiDBEnableTSOFollowerProxy:
-		val := variable.TiDBOptOn(sVal)
-		err := do.SetPDClientDynamicOption(pd.EnableTSOFollowerProxy, val)
-		if err != nil {
-			break
-		}
-		variable.EnableTSOFollowerProxy.Store(val)
-	}
-}
-
-// SetPDClientDynamicOption is used to set the dynamic option into the PD client.
-func (do *Domain) SetPDClientDynamicOption(option pd.DynamicOption, val interface{}) error {
-	store, ok := do.store.(interface{ GetPDClient() pd.Client })
-	if !ok {
-		return nil
-	}
-	pdClient := store.GetPDClient()
-	if pdClient == nil {
-		return nil
-	}
-	return pdClient.UpdateOption(option, val)
-}
-
-// SetStatsCacheCapacity sets statsCache cap
-func (do *Domain) SetStatsCacheCapacity(c int64) {
-	do.StatsHandle().SetStatsCacheCapacity(c)
-	logutil.BgLogger().Info("update stats cache capacity successfully", zap.Int64("capacity", c))
-}

executor/set.go

@@ -16,9 +16,7 @@ package executor
 
 import (
 	"context"
-	"strconv"
 	"strings"
-	"time"
 
 	"github.com/pingcap/errors"
 	"github.com/pingcap/tidb/domain"
@@ -34,7 +32,6 @@ import (
 	"github.com/pingcap/tidb/util/collate"
 	"github.com/pingcap/tidb/util/gcutil"
 	"github.com/pingcap/tidb/util/logutil"
-	pd "github.com/tikv/pd/client"
 	"go.uber.org/zap"
 )
 
@@ -134,11 +131,6 @@ func (e *SetExecutor) setSysVariable(ctx context.Context, name string, v *expres
 		if err != nil {
 			return err
 		}
-		// Some PD client dynamic options need to be checked first and set here.
-		err = e.checkPDClientDynamicOption(name, sessionVars)
-		if err != nil {
-			return err
-		}
 		err = plugin.ForeachPlugin(plugin.Audit, func(p *plugin.Plugin) error {
 			auditPlugin := plugin.DeclareAuditManifest(p.Manifest)
 			if auditPlugin.OnGlobalVariableEvent != nil {
@@ -214,45 +206,6 @@ func (e *SetExecutor) setSysVariable(ctx context.Context, name string, v *expres
 	return nil
 }
 
-func (e *SetExecutor) checkPDClientDynamicOption(name string, sessionVars *variable.SessionVars) error {
-	if name != variable.TiDBTSOClientBatchMaxWaitTime &&
-		name != variable.TiDBEnableTSOFollowerProxy {
-		return nil
-	}
-	var (
-		err    error
-		valStr string
-	)
-	valStr, err = sessionVars.GlobalVarsAccessor.GetGlobalSysVar(name)
-	if err != nil {
-		return err
-	}
-	switch name {
-	case variable.TiDBTSOClientBatchMaxWaitTime:
-		var val float64
-		val, err = strconv.ParseFloat(valStr, 64)
-		if err != nil {
-			return err
-		}
-		err = domain.GetDomain(e.ctx).SetPDClientDynamicOption(
-			pd.MaxTSOBatchWaitInterval,
-			time.Duration(float64(time.Millisecond)*val),
-		)
-		if err != nil {
-			return err
-		}
-		logutil.BgLogger().Info("set pd client dynamic option", zap.Uint64("conn", sessionVars.ConnectionID), zap.String("name", name), zap.String("val", valStr))
-	case variable.TiDBEnableTSOFollowerProxy:
-		val := variable.TiDBOptOn(valStr)
-		err = domain.GetDomain(e.ctx).SetPDClientDynamicOption(pd.EnableTSOFollowerProxy, val)
-		if err != nil {
-			return err
-		}
-		logutil.BgLogger().Info("set pd client dynamic option", zap.Uint64("conn", sessionVars.ConnectionID), zap.String("name", name), zap.String("val", valStr))
-	}
-	return nil
-}
-
 func (e *SetExecutor) setCharset(cs, co string, isSetName bool) error {
 	var err error
 	sessionVars := e.ctx.GetSessionVars()

sessionctx/variable/sysvar.go

@@ -495,13 +495,13 @@ var defaultSysVars = []*SysVar{
 			return strconv.FormatFloat(MaxTSOBatchWaitInterval.Load(), 'f', -1, 64), nil
 		},
 		SetGlobal: func(s *SessionVars, val string) error {
-			MaxTSOBatchWaitInterval.Store(tidbOptFloat64(val, DefTiDBTSOClientBatchMaxWaitTime))
+			SetPDClientDynamicOption(TiDBTSOClientBatchMaxWaitTime, val)
 			return nil
 		}},
 	{Scope: ScopeGlobal, Name: TiDBEnableTSOFollowerProxy, Value: BoolToOnOff(DefTiDBEnableTSOFollowerProxy), Type: TypeBool, GetGlobal: func(sv *SessionVars) (string, error) {
 		return BoolToOnOff(EnableTSOFollowerProxy.Load()), nil
 	}, SetGlobal: func(s *SessionVars, val string) error {
-		EnableTSOFollowerProxy.Store(TiDBOptOn(val))
+		SetPDClientDynamicOption(TiDBEnableTSOFollowerProxy, val)
 		return nil
 	}},
 	{Scope: ScopeGlobal, Name: TiDBEnableLocalTxn, Value: BoolToOnOff(DefTiDBEnableLocalTxn), Hidden: true, Type: TypeBool, GetGlobal: func(sv *SessionVars) (string, error) {

sessionctx/variable/tidb_vars.go

@@ -1113,6 +1113,8 @@ var (
 	GetMemQuotaAnalyze func() int64 = nil
 	// SetStatsCacheCapacity is the func registered by domain to set statsCache memory quota.
 	SetStatsCacheCapacity atomic.Value
+	// SetPDClientDynamicOption is the func registered by domain
+	SetPDClientDynamicOption func(string, string) = nil
 	// SwitchConcurrentDDL is the func registered by DDL to switch concurrent DDL.
 	SwitchConcurrentDDL func(bool) error = nil
 	// SwitchMDL is the func registered by DDL to switch MDL.