350 lines
11 KiB
Go
350 lines
11 KiB
Go
// Copyright 2016 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package executor
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import (
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"context"
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"strings"
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"github.com/pingcap/errors"
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"github.com/pingcap/tidb/pkg/config"
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"github.com/pingcap/tidb/pkg/disttask/framework/storage"
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"github.com/pingcap/tidb/pkg/domain"
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"github.com/pingcap/tidb/pkg/executor/internal/exec"
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"github.com/pingcap/tidb/pkg/expression"
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"github.com/pingcap/tidb/pkg/parser/ast"
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"github.com/pingcap/tidb/pkg/parser/charset"
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"github.com/pingcap/tidb/pkg/parser/mysql"
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"github.com/pingcap/tidb/pkg/plugin"
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"github.com/pingcap/tidb/pkg/privilege"
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"github.com/pingcap/tidb/pkg/sessionctx"
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"github.com/pingcap/tidb/pkg/sessionctx/variable"
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"github.com/pingcap/tidb/pkg/table/temptable"
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"github.com/pingcap/tidb/pkg/util/chunk"
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"github.com/pingcap/tidb/pkg/util/collate"
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"github.com/pingcap/tidb/pkg/util/dbterror/exeerrors"
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"github.com/pingcap/tidb/pkg/util/dbterror/plannererrors"
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disttaskutil "github.com/pingcap/tidb/pkg/util/disttask"
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"github.com/pingcap/tidb/pkg/util/gcutil"
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"github.com/pingcap/tidb/pkg/util/logutil"
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"github.com/pingcap/tidb/pkg/util/sem"
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"go.uber.org/zap"
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)
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// SetExecutor executes set statement.
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type SetExecutor struct {
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exec.BaseExecutor
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vars []*expression.VarAssignment
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done bool
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}
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// Next implements the Executor Next interface.
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func (e *SetExecutor) Next(ctx context.Context, req *chunk.Chunk) error {
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req.Reset()
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if e.done {
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return nil
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}
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e.done = true
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sctx := e.Ctx()
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sessionVars := sctx.GetSessionVars()
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for _, v := range e.vars {
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// Variable is case insensitive, we use lower case.
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if v.Name == ast.SetNames || v.Name == ast.SetCharset {
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// This is set charset stmt.
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if v.IsDefault {
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err := e.setCharset(mysql.DefaultCharset, "", v.Name == ast.SetNames)
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if err != nil {
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return err
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}
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continue
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}
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dt, err := v.Expr.(*expression.Constant).Eval(sctx.GetExprCtx().GetEvalCtx(), chunk.Row{})
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if err != nil {
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return err
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}
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cs := dt.GetString()
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var co string
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if v.ExtendValue != nil {
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co = v.ExtendValue.Value.GetString()
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}
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err = e.setCharset(cs, co, v.Name == ast.SetNames)
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if err != nil {
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return err
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}
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continue
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}
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name := strings.ToLower(v.Name)
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if !v.IsSystem {
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// Set user variable.
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value, err := v.Expr.Eval(sctx.GetExprCtx().GetEvalCtx(), chunk.Row{})
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if err != nil {
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return err
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}
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if value.IsNull() {
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sessionVars.UnsetUserVar(name)
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} else {
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sessionVars.SetUserVarVal(name, value)
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sessionVars.SetUserVarType(name, v.Expr.GetType(sctx.GetExprCtx().GetEvalCtx()))
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}
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continue
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}
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if err := e.setSysVariable(ctx, name, v); err != nil {
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return err
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}
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}
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return nil
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}
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func (e *SetExecutor) setSysVariable(ctx context.Context, name string, v *expression.VarAssignment) error {
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sessionVars := e.Ctx().GetSessionVars()
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sysVar := variable.GetSysVar(name)
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if sysVar == nil {
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if variable.IsRemovedSysVar(name) {
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return nil // removed vars permit parse-but-ignore
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}
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return variable.ErrUnknownSystemVar.GenWithStackByArgs(name)
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}
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if sysVar.RequireDynamicPrivileges != nil {
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semEnabled := sem.IsEnabled()
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pm := privilege.GetPrivilegeManager(e.Ctx())
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privs := sysVar.RequireDynamicPrivileges(v.IsGlobal, semEnabled)
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for _, priv := range privs {
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if !pm.RequestDynamicVerification(sessionVars.ActiveRoles, priv, false) {
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msg := priv
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if !semEnabled {
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msg = "SUPER or " + msg
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}
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return plannererrors.ErrSpecificAccessDenied.GenWithStackByArgs(msg)
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}
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}
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}
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if sysVar.IsNoop && !variable.EnableNoopVariables.Load() {
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// The variable is a noop. For compatibility we allow it to still
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// be changed, but we append a warning since users might be expecting
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// something that's not going to happen.
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sessionVars.StmtCtx.AppendWarning(exeerrors.ErrSettingNoopVariable.FastGenByArgs(sysVar.Name))
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}
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if sysVar.HasInstanceScope() && !v.IsGlobal && sessionVars.EnableLegacyInstanceScope {
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// For backward compatibility we will change the v.IsGlobal to true,
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// and append a warning saying this will not be supported in future.
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v.IsGlobal = true
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sessionVars.StmtCtx.AppendWarning(exeerrors.ErrInstanceScope.FastGenByArgs(sysVar.Name))
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}
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if v.IsGlobal {
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valStr, err := e.getVarValue(ctx, v, sysVar)
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if err != nil {
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return err
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}
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err = sessionVars.GlobalVarsAccessor.SetGlobalSysVar(ctx, name, valStr)
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if err != nil {
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return err
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}
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err = plugin.ForeachPlugin(plugin.Audit, func(p *plugin.Plugin) error {
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auditPlugin := plugin.DeclareAuditManifest(p.Manifest)
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if auditPlugin.OnGlobalVariableEvent != nil {
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auditPlugin.OnGlobalVariableEvent(context.Background(), e.Ctx().GetSessionVars(), name, valStr)
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}
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return nil
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})
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showValStr := valStr
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if name == variable.TiDBCloudStorageURI {
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showValStr = ast.RedactURL(showValStr)
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}
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logutil.BgLogger().Info("set global var", zap.Uint64("conn", sessionVars.ConnectionID), zap.String("name", name), zap.String("val", showValStr))
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if name == variable.TiDBServiceScope {
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dom := domain.GetDomain(e.Ctx())
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oldConfig := config.GetGlobalConfig()
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if oldConfig.Instance.TiDBServiceScope != valStr {
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newConfig := *oldConfig
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newConfig.Instance.TiDBServiceScope = valStr
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config.StoreGlobalConfig(&newConfig)
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}
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serverID := disttaskutil.GenerateSubtaskExecID(ctx, dom.DDL().GetID())
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taskMgr, err := storage.GetTaskManager()
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if err != nil {
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return err
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}
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return taskMgr.InitMetaSession(ctx, e.Ctx(), serverID, valStr)
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}
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return err
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}
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// Set session variable
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valStr, err := e.getVarValue(ctx, v, nil)
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if err != nil {
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return err
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}
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getSnapshotTSByName := func() uint64 {
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if name == variable.TiDBSnapshot {
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return sessionVars.SnapshotTS
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} else if name == variable.TiDBTxnReadTS {
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return sessionVars.TxnReadTS.PeakTxnReadTS()
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}
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return 0
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}
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oldSnapshotTS := getSnapshotTSByName()
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fallbackOldSnapshotTS := func() {
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if name == variable.TiDBSnapshot {
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sessionVars.SnapshotTS = oldSnapshotTS
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} else if name == variable.TiDBTxnReadTS {
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sessionVars.TxnReadTS.SetTxnReadTS(oldSnapshotTS)
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}
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}
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if sessionVars.InTxn() {
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if name == variable.TxnIsolationOneShot ||
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name == variable.TiDBTxnReadTS {
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return errors.Trace(exeerrors.ErrCantChangeTxCharacteristics)
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}
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if name == variable.TiDBSnapshot && sessionVars.TxnCtx.IsStaleness {
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return errors.Trace(exeerrors.ErrCantChangeTxCharacteristics)
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}
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}
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err = sessionVars.SetSystemVar(name, valStr)
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if err != nil {
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return err
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}
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newSnapshotTS := getSnapshotTSByName()
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newSnapshotIsSet := newSnapshotTS > 0 && newSnapshotTS != oldSnapshotTS
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if newSnapshotIsSet {
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if name == variable.TiDBTxnReadTS {
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err = sessionctx.ValidateStaleReadTS(ctx, e.Ctx().GetSessionVars().StmtCtx, e.Ctx().GetStore(), newSnapshotTS)
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} else {
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err = sessionctx.ValidateSnapshotReadTS(ctx, e.Ctx(), newSnapshotTS)
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// Also check gc safe point for snapshot read.
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// We don't check snapshot with gc safe point for read_ts
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// Client-go will automatically check the snapshotTS with gc safe point. It's unnecessary to check gc safe point during set executor.
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if err == nil {
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err = gcutil.ValidateSnapshot(e.Ctx(), newSnapshotTS)
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}
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}
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if err != nil {
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fallbackOldSnapshotTS()
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return err
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}
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}
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err = e.loadSnapshotInfoSchemaIfNeeded(name, newSnapshotTS)
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if err != nil {
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fallbackOldSnapshotTS()
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return err
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}
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// Clients are often noisy in setting session variables such as
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// autocommit, timezone, query cache
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logutil.BgLogger().Debug("set session var", zap.Uint64("conn", sessionVars.ConnectionID), zap.String("name", name), zap.String("val", valStr))
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return nil
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}
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func (e *SetExecutor) setCharset(cs, co string, isSetName bool) error {
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var err error
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sessionVars := e.Ctx().GetSessionVars()
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if co == "" {
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if co, err = charset.GetDefaultCollation(cs); err != nil {
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return err
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}
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} else {
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var coll *charset.Collation
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if coll, err = collate.GetCollationByName(co); err != nil {
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return err
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}
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if coll.CharsetName != cs {
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return charset.ErrCollationCharsetMismatch.GenWithStackByArgs(coll.Name, cs)
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}
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}
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if isSetName {
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for _, v := range variable.SetNamesVariables {
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if err = sessionVars.SetSystemVar(v, cs); err != nil {
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return errors.Trace(err)
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}
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}
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return errors.Trace(sessionVars.SetSystemVar(variable.CollationConnection, co))
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}
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// Set charset statement, see also https://dev.mysql.com/doc/refman/8.0/en/set-character-set.html.
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for _, v := range variable.SetCharsetVariables {
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if err = sessionVars.SetSystemVar(v, cs); err != nil {
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return errors.Trace(err)
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}
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}
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csDB, err := sessionVars.GlobalVarsAccessor.GetGlobalSysVar(variable.CharsetDatabase)
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if err != nil {
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return err
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}
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coDB, err := sessionVars.GlobalVarsAccessor.GetGlobalSysVar(variable.CollationDatabase)
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if err != nil {
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return err
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}
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err = sessionVars.SetSystemVar(variable.CharacterSetConnection, csDB)
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if err != nil {
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return errors.Trace(err)
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}
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return errors.Trace(sessionVars.SetSystemVar(variable.CollationConnection, coDB))
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}
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func (e *SetExecutor) getVarValue(ctx context.Context, v *expression.VarAssignment, sysVar *variable.SysVar) (value string, err error) {
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if v.IsDefault {
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// To set a SESSION variable to the GLOBAL value or a GLOBAL value
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// to the compiled-in MySQL default value, use the DEFAULT keyword.
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// See http://dev.mysql.com/doc/refman/5.7/en/set-statement.html
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if sysVar != nil {
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defVal := variable.GlobalSystemVariableInitialValue(sysVar.Name, sysVar.Value)
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return defVal, nil
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}
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return e.Ctx().GetSessionVars().GetGlobalSystemVar(ctx, v.Name)
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}
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nativeVal, err := v.Expr.Eval(e.Ctx().GetExprCtx().GetEvalCtx(), chunk.Row{})
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if err != nil || nativeVal.IsNull() {
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return "", err
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}
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value, err = nativeVal.ToString()
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if err != nil {
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return "", err
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}
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// We need to clone the string because the value is constructed by `hack.String` in Datum which reuses the under layer `[]byte`
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// instead of allocating some new spaces. The `[]byte` in Datum will be reused in `chunk.Chunk` by different statements in session.
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// If we do not clone the value, the system variable will have a risk to be modified by other statements.
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return strings.Clone(value), nil
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}
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func (e *SetExecutor) loadSnapshotInfoSchemaIfNeeded(name string, snapshotTS uint64) error {
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if name != variable.TiDBSnapshot && name != variable.TiDBTxnReadTS {
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return nil
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}
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return loadSnapshotInfoSchemaIfNeeded(e.Ctx(), snapshotTS)
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}
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func loadSnapshotInfoSchemaIfNeeded(sctx sessionctx.Context, snapshotTS uint64) error {
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vars := sctx.GetSessionVars()
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if snapshotTS == 0 {
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vars.SnapshotInfoschema = nil
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return nil
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}
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logutil.BgLogger().Info("load snapshot info schema",
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zap.Uint64("conn", vars.ConnectionID),
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zap.Uint64("SnapshotTS", snapshotTS))
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dom := domain.GetDomain(sctx)
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snapInfo, err := dom.GetSnapshotInfoSchema(snapshotTS)
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if err != nil {
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return err
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}
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vars.SnapshotInfoschema = temptable.AttachLocalTemporaryTableInfoSchema(sctx, snapInfo)
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return nil
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}
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