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// Copyright 2016 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package executor
import (
"context"
"fmt"
"strings"
"github.com/pingcap/errors"
"github.com/pingcap/parser/ast"
"github.com/pingcap/parser/charset"
"github.com/pingcap/parser/mysql"
"github.com/pingcap/parser/terror"
"github.com/pingcap/tidb/domain"
"github.com/pingcap/tidb/expression"
"github.com/pingcap/tidb/plugin"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/chunk"
"github.com/pingcap/tidb/util/collate"
"github.com/pingcap/tidb/util/gcutil"
"github.com/pingcap/tidb/util/logutil"
"github.com/pingcap/tidb/util/stmtsummary"
"go.uber.org/zap"
)
const (
scopeGlobal = "global"
scopeSession = "session"
)
// SetExecutor executes set statement.
type SetExecutor struct {
baseExecutor
vars []*expression.VarAssignment
done bool
}
// Next implements the Executor Next interface.
func (e *SetExecutor) Next(ctx context.Context, req *chunk.Chunk) error {
req.Reset()
if e.done {
return nil
}
e.done = true
sessionVars := e.ctx.GetSessionVars()
for _, v := range e.vars {
// Variable is case insensitive, we use lower case.
if v.Name == ast.SetNames || v.Name == ast.SetCharset {
// This is set charset stmt.
if v.IsDefault {
err := e.setCharset(mysql.DefaultCharset, "", v.Name == ast.SetNames)
if err != nil {
return err
}
continue
}
dt, err := v.Expr.(*expression.Constant).Eval(chunk.Row{})
if err != nil {
return err
}
cs := dt.GetString()
var co string
if v.ExtendValue != nil {
co = v.ExtendValue.Value.GetString()
}
err = e.setCharset(cs, co, v.Name == ast.SetNames)
if err != nil {
return err
}
continue
}
name := strings.ToLower(v.Name)
if !v.IsSystem {
// Set user variable.
value, err := v.Expr.Eval(chunk.Row{})
if err != nil {
return err
}
sessionVars.UsersLock.Lock()
if value.IsNull() {
delete(sessionVars.Users, name)
delete(sessionVars.UserVarTypes, name)
} else {
sessionVars.Users[name] = value
sessionVars.UserVarTypes[name] = v.Expr.GetType()
}
sessionVars.UsersLock.Unlock()
continue
}
syns := e.getSynonyms(name)
// Set system variable
for _, n := range syns {
err := e.setSysVariable(n, v)
if err != nil {
return err
}
}
}
return nil
}
func (e *SetExecutor) getSynonyms(varName string) []string {
synonyms, ok := variable.SynonymsSysVariables[varName]
if ok {
return synonyms
}
synonyms = []string{varName}
return synonyms
}
func (e *SetExecutor) setSysVariable(name string, v *expression.VarAssignment) error {
sessionVars := e.ctx.GetSessionVars()
sysVar := variable.GetSysVar(name)
if sysVar == nil {
return variable.ErrUnknownSystemVar.GenWithStackByArgs(name)
}
if sysVar.Scope == variable.ScopeNone {
return errors.Errorf("Variable '%s' is a read only variable", name)
}
var valStr string
var scopeStr string
if v.IsGlobal {
scopeStr = scopeGlobal
// Set global scope system variable.
if sysVar.Scope&variable.ScopeGlobal == 0 {
return errors.Errorf("Variable '%s' is a SESSION variable and can't be used with SET GLOBAL", name)
}
value, err := e.getVarValue(v, sysVar)
if err != nil {
return err
}
if value.IsNull() {
value.SetString("", mysql.DefaultCollationName)
}
valStr, err = value.ToString()
if err != nil {
return err
}
err = sessionVars.GlobalVarsAccessor.SetGlobalSysVar(name, valStr)
if err != nil {
return err
}
err = plugin.ForeachPlugin(plugin.Audit, func(p *plugin.Plugin) error {
auditPlugin := plugin.DeclareAuditManifest(p.Manifest)
if auditPlugin.OnGlobalVariableEvent != nil {
auditPlugin.OnGlobalVariableEvent(context.Background(), e.ctx.GetSessionVars(), name, valStr)
}
return nil
})
if err != nil {
return err
}
} else {
scopeStr = scopeSession
// Set session scope system variable.
if sysVar.Scope&variable.ScopeSession == 0 {
return errors.Errorf("Variable '%s' is a GLOBAL variable and should be set with SET GLOBAL", name)
}
value, err := e.getVarValue(v, nil)
if err != nil {
return err
}
oldSnapshotTS := sessionVars.SnapshotTS
if name == variable.TxnIsolationOneShot && sessionVars.InTxn() {
return errors.Trace(ErrCantChangeTxCharacteristics)
}
if name == variable.TiDBFoundInPlanCache {
sessionVars.StmtCtx.AppendWarning(fmt.Errorf("Set operation for '%s' will not take effect", variable.TiDBFoundInPlanCache))
return nil
}
err = variable.SetSessionSystemVar(sessionVars, name, value)
if err != nil {
return err
}
newSnapshotIsSet := sessionVars.SnapshotTS > 0 && sessionVars.SnapshotTS != oldSnapshotTS
if newSnapshotIsSet {
err = gcutil.ValidateSnapshot(e.ctx, sessionVars.SnapshotTS)
if err != nil {
sessionVars.SnapshotTS = oldSnapshotTS
return err
}
}
err = e.loadSnapshotInfoSchemaIfNeeded(name)
if err != nil {
sessionVars.SnapshotTS = oldSnapshotTS
return err
}
if value.IsNull() {
valStr = "NULL"
} else {
var err error
valStr, err = value.ToString()
terror.Log(err)
}
}
if scopeStr == scopeGlobal {
logutil.BgLogger().Info(fmt.Sprintf("set %s var", scopeStr), zap.Uint64("conn", sessionVars.ConnectionID), zap.String("name", name), zap.String("val", valStr))
} else {
// Clients are often noisy in setting session variables such as
// autocommit, timezone, query cache
logutil.BgLogger().Debug(fmt.Sprintf("set %s var", scopeStr), zap.Uint64("conn", sessionVars.ConnectionID), zap.String("name", name), zap.String("val", valStr))
}
switch name {
case variable.TiDBEnableStmtSummary:
return stmtsummary.StmtSummaryByDigestMap.SetEnabled(valStr, !v.IsGlobal)
case variable.TiDBStmtSummaryInternalQuery:
return stmtsummary.StmtSummaryByDigestMap.SetEnabledInternalQuery(valStr, !v.IsGlobal)
case variable.TiDBStmtSummaryRefreshInterval:
return stmtsummary.StmtSummaryByDigestMap.SetRefreshInterval(valStr, !v.IsGlobal)
case variable.TiDBStmtSummaryHistorySize:
return stmtsummary.StmtSummaryByDigestMap.SetHistorySize(valStr, !v.IsGlobal)
case variable.TiDBStmtSummaryMaxStmtCount:
return stmtsummary.StmtSummaryByDigestMap.SetMaxStmtCount(valStr, !v.IsGlobal)
case variable.TiDBStmtSummaryMaxSQLLength:
return stmtsummary.StmtSummaryByDigestMap.SetMaxSQLLength(valStr, !v.IsGlobal)
case variable.TiDBCapturePlanBaseline:
variable.CapturePlanBaseline.Set(strings.ToLower(valStr), !v.IsGlobal)
}
return nil
}
func (e *SetExecutor) setCharset(cs, co string, isSetName bool) error {
var err error
if len(co) == 0 {
if co, err = charset.GetDefaultCollation(cs); err != nil {
return err
}
} else {
var coll *charset.Collation
if coll, err = collate.GetCollationByName(co); err != nil {
return err
}
if coll.CharsetName != cs {
return charset.ErrCollationCharsetMismatch.GenWithStackByArgs(coll.Name, cs)
}
}
sessionVars := e.ctx.GetSessionVars()
if isSetName {
for _, v := range variable.SetNamesVariables {
if err = sessionVars.SetSystemVar(v, cs); err != nil {
return errors.Trace(err)
}
}
return errors.Trace(sessionVars.SetSystemVar(variable.CollationConnection, co))
}
// Set charset statement, see also https://dev.mysql.com/doc/refman/8.0/en/set-character-set.html.
for _, v := range variable.SetCharsetVariables {
if err = sessionVars.SetSystemVar(v, cs); err != nil {
return errors.Trace(err)
}
}
csDb, err := sessionVars.GlobalVarsAccessor.GetGlobalSysVar(variable.CharsetDatabase)
if err != nil {
return err
}
coDb, err := sessionVars.GlobalVarsAccessor.GetGlobalSysVar(variable.CollationDatabase)
if err != nil {
return err
}
err = sessionVars.SetSystemVar(variable.CharacterSetConnection, csDb)
if err != nil {
return errors.Trace(err)
}
return errors.Trace(sessionVars.SetSystemVar(variable.CollationConnection, coDb))
}
func (e *SetExecutor) getVarValue(v *expression.VarAssignment, sysVar *variable.SysVar) (value types.Datum, err error) {
if v.IsDefault {
// To set a SESSION variable to the GLOBAL value or a GLOBAL value
// to the compiled-in MySQL default value, use the DEFAULT keyword.
// See http://dev.mysql.com/doc/refman/5.7/en/set-statement.html
if sysVar != nil {
value = types.NewStringDatum(sysVar.Value)
} else {
s, err1 := variable.GetGlobalSystemVar(e.ctx.GetSessionVars(), v.Name)
if err1 != nil {
return value, err1
}
value = types.NewStringDatum(s)
}
return
}
value, err = v.Expr.Eval(chunk.Row{})
return value, err
}
func (e *SetExecutor) loadSnapshotInfoSchemaIfNeeded(name string) error {
if name != variable.TiDBSnapshot {
return nil
}
vars := e.ctx.GetSessionVars()
if vars.SnapshotTS == 0 {
vars.SnapshotInfoschema = nil
return nil
}
logutil.BgLogger().Info("load snapshot info schema", zap.Uint64("conn", vars.ConnectionID), zap.Uint64("SnapshotTS", vars.SnapshotTS))
dom := domain.GetDomain(e.ctx)
snapInfo, err := dom.GetSnapshotInfoSchema(vars.SnapshotTS)
if err != nil {
return err
}
vars.SnapshotInfoschema = snapInfo
return nil
}