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adapter.go
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// Copyright 2015 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 (
"fmt"
"math"
"strings"
"time"
"github.com/pingcap/tidb/ast"
"github.com/pingcap/tidb/config"
"github.com/pingcap/tidb/domain"
"github.com/pingcap/tidb/expression"
"github.com/pingcap/tidb/infoschema"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/metrics"
"github.com/pingcap/tidb/model"
"github.com/pingcap/tidb/mysql"
plannercore "github.com/pingcap/tidb/planner/core"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/terror"
"github.com/pingcap/tidb/util/chunk"
"github.com/pingcap/tidb/util/logutil"
"github.com/pkg/errors"
log "github.com/sirupsen/logrus"
"golang.org/x/net/context"
)
type processinfoSetter interface {
SetProcessInfo(string)
}
// recordSet wraps an executor, implements ast.RecordSet interface
type recordSet struct {
fields []*ast.ResultField
executor Executor
stmt *ExecStmt
processinfo processinfoSetter
lastErr error
txnStartTS uint64
}
func (a *recordSet) Fields() []*ast.ResultField {
if len(a.fields) == 0 {
a.fields = schema2ResultFields(a.executor.Schema(), a.stmt.Ctx.GetSessionVars().CurrentDB)
}
return a.fields
}
func schema2ResultFields(schema *expression.Schema, defaultDB string) (rfs []*ast.ResultField) {
rfs = make([]*ast.ResultField, 0, schema.Len())
for _, col := range schema.Columns {
dbName := col.DBName.O
if dbName == "" && col.TblName.L != "" {
dbName = defaultDB
}
origColName := col.OrigColName
if origColName.L == "" {
origColName = col.ColName
}
rf := &ast.ResultField{
ColumnAsName: col.ColName,
TableAsName: col.TblName,
DBName: model.NewCIStr(dbName),
Table: &model.TableInfo{Name: col.OrigTblName},
Column: &model.ColumnInfo{
FieldType: *col.RetType,
Name: origColName,
},
}
rfs = append(rfs, rf)
}
return rfs
}
// Next use uses recordSet's executor to get next available chunk for later usage.
// If chunk does not contain any rows, then we update last query found rows in session variable as current found rows.
// The reason we need update is that chunk with 0 rows indicating we already finished current query, we need prepare for
// next query.
// If stmt is not nil and chunk with some rows inside, we simply update last query found rows by the number of row in chunk.
func (a *recordSet) Next(ctx context.Context, chk *chunk.Chunk) error {
err := a.executor.Next(ctx, chk)
if err != nil {
a.lastErr = err
return errors.Trace(err)
}
numRows := chk.NumRows()
if numRows == 0 {
if a.stmt != nil {
a.stmt.Ctx.GetSessionVars().LastFoundRows = a.stmt.Ctx.GetSessionVars().StmtCtx.FoundRows()
}
return nil
}
if a.stmt != nil {
a.stmt.Ctx.GetSessionVars().StmtCtx.AddFoundRows(uint64(numRows))
}
return nil
}
// NewChunk create a new chunk using NewChunk function in chunk package.
func (a *recordSet) NewChunk() *chunk.Chunk {
return a.executor.newFirstChunk()
}
func (a *recordSet) Close() error {
err := a.executor.Close()
a.stmt.LogSlowQuery(a.txnStartTS, a.lastErr == nil)
if a.processinfo != nil {
a.processinfo.SetProcessInfo("")
}
return errors.Trace(err)
}
// ExecStmt implements the ast.Statement interface, it builds a planner.Plan to an ast.Statement.
type ExecStmt struct {
// InfoSchema stores a reference to the schema information.
InfoSchema infoschema.InfoSchema
// Plan stores a reference to the final physical plan.
Plan plannercore.Plan
// Expensive represents whether this query is an expensive one.
Expensive bool
// Cacheable represents whether the physical plan can be cached.
Cacheable bool
// Text represents the origin query text.
Text string
StmtNode ast.StmtNode
Ctx sessionctx.Context
// StartTime stands for the starting time when executing the statement.
StartTime time.Time
isPreparedStmt bool
}
// OriginText returns original statement as a string.
func (a *ExecStmt) OriginText() string {
return a.Text
}
// IsPrepared returns true if stmt is a prepare statement.
func (a *ExecStmt) IsPrepared() bool {
return a.isPreparedStmt
}
// IsReadOnly returns true if a statement is read only.
// It will update readOnlyCheckStmt if current ExecStmt can be conveted to
// a plannercore.Execute. Last step is using ast.IsReadOnly function to determine
// a statement is read only or not.
func (a *ExecStmt) IsReadOnly() bool {
readOnlyCheckStmt := a.StmtNode
if checkPlan, ok := a.Plan.(*plannercore.Execute); ok {
readOnlyCheckStmt = checkPlan.Stmt
}
return ast.IsReadOnly(readOnlyCheckStmt)
}
// RebuildPlan rebuilds current execute statement plan.
// It returns the current information schema version that 'a' is using.
func (a *ExecStmt) RebuildPlan() (int64, error) {
is := GetInfoSchema(a.Ctx)
a.InfoSchema = is
if err := plannercore.Preprocess(a.Ctx, a.StmtNode, is, false); err != nil {
return 0, errors.Trace(err)
}
p, err := plannercore.Optimize(a.Ctx, a.StmtNode, is)
if err != nil {
return 0, errors.Trace(err)
}
a.Plan = p
return is.SchemaMetaVersion(), nil
}
// Exec builds an Executor from a plan. If the Executor doesn't return result,
// like the INSERT, UPDATE statements, it executes in this function, if the Executor returns
// result, execution is done after this function returns, in the returned ast.RecordSet Next method.
func (a *ExecStmt) Exec(ctx context.Context) (ast.RecordSet, error) {
a.StartTime = time.Now()
sctx := a.Ctx
if _, ok := a.Plan.(*plannercore.Analyze); ok && sctx.GetSessionVars().InRestrictedSQL {
oriStats, _ := sctx.GetSessionVars().GetSystemVar(variable.TiDBBuildStatsConcurrency)
oriScan := sctx.GetSessionVars().DistSQLScanConcurrency
oriIndex := sctx.GetSessionVars().IndexSerialScanConcurrency
oriIso, _ := sctx.GetSessionVars().GetSystemVar(variable.TxnIsolation)
terror.Log(errors.Trace(sctx.GetSessionVars().SetSystemVar(variable.TiDBBuildStatsConcurrency, "1")))
sctx.GetSessionVars().DistSQLScanConcurrency = 1
sctx.GetSessionVars().IndexSerialScanConcurrency = 1
terror.Log(errors.Trace(sctx.GetSessionVars().SetSystemVar(variable.TxnIsolation, ast.ReadCommitted)))
defer func() {
terror.Log(errors.Trace(sctx.GetSessionVars().SetSystemVar(variable.TiDBBuildStatsConcurrency, oriStats)))
sctx.GetSessionVars().DistSQLScanConcurrency = oriScan
sctx.GetSessionVars().IndexSerialScanConcurrency = oriIndex
terror.Log(errors.Trace(sctx.GetSessionVars().SetSystemVar(variable.TxnIsolation, oriIso)))
}()
}
e, err := a.buildExecutor(sctx)
if err != nil {
return nil, errors.Trace(err)
}
if err := e.Open(ctx); err != nil {
terror.Call(e.Close)
return nil, errors.Trace(err)
}
var pi processinfoSetter
if raw, ok := sctx.(processinfoSetter); ok {
pi = raw
sql := a.OriginText()
if simple, ok := a.Plan.(*plannercore.Simple); ok && simple.Statement != nil {
if ss, ok := simple.Statement.(ast.SensitiveStmtNode); ok {
// Use SecureText to avoid leak password information.
sql = ss.SecureText()
}
}
// Update processinfo, ShowProcess() will use it.
pi.SetProcessInfo(sql)
}
// If the executor doesn't return any result to the client, we execute it without delay.
if e.Schema().Len() == 0 {
return a.handleNoDelayExecutor(ctx, sctx, e, pi)
} else if proj, ok := e.(*ProjectionExec); ok && proj.calculateNoDelay {
// Currently this is only for the "DO" statement. Take "DO 1, @a=2;" as an example:
// the Projection has two expressions and two columns in the schema, but we should
// not return the result of the two expressions.
return a.handleNoDelayExecutor(ctx, sctx, e, pi)
}
return &recordSet{
executor: e,
stmt: a,
processinfo: pi,
txnStartTS: sctx.Txn().StartTS(),
}, nil
}
func (a *ExecStmt) handleNoDelayExecutor(ctx context.Context, sctx sessionctx.Context, e Executor, pi processinfoSetter) (ast.RecordSet, error) {
// Check if "tidb_snapshot" is set for the write executors.
// In history read mode, we can not do write operations.
switch e.(type) {
case *DeleteExec, *InsertExec, *UpdateExec, *ReplaceExec, *LoadDataExec, *DDLExec:
snapshotTS := sctx.GetSessionVars().SnapshotTS
if snapshotTS != 0 {
return nil, errors.New("can not execute write statement when 'tidb_snapshot' is set")
}
}
var err error
defer func() {
if pi != nil {
pi.SetProcessInfo("")
}
terror.Log(errors.Trace(e.Close()))
txnTS := uint64(0)
if sctx.Txn() != nil {
txnTS = sctx.Txn().StartTS()
}
a.LogSlowQuery(txnTS, err == nil)
}()
err = e.Next(ctx, e.newFirstChunk())
if err != nil {
return nil, errors.Trace(err)
}
return nil, nil
}
// buildExecutor build a executor from plan, prepared statement may need additional procedure.
func (a *ExecStmt) buildExecutor(ctx sessionctx.Context) (Executor, error) {
if _, ok := a.Plan.(*plannercore.Execute); !ok {
// Do not sync transaction for Execute statement, because the real optimization work is done in
// "ExecuteExec.Build".
var err error
isPointGet := IsPointGetWithPKOrUniqueKeyByAutoCommit(ctx, a.Plan)
if isPointGet {
log.Debugf("con:%d InitTxnWithStartTS %s", ctx.GetSessionVars().ConnectionID, a.Text)
err = ctx.InitTxnWithStartTS(math.MaxUint64)
} else {
log.Debugf("con:%d ActivePendingTxn %s", ctx.GetSessionVars().ConnectionID, a.Text)
err = ctx.ActivePendingTxn()
}
if err != nil {
return nil, errors.Trace(err)
}
stmtCtx := ctx.GetSessionVars().StmtCtx
if stmtPri := stmtCtx.Priority; stmtPri == mysql.NoPriority {
switch {
case isPointGet:
stmtCtx.Priority = kv.PriorityHigh
case a.Expensive:
stmtCtx.Priority = kv.PriorityLow
}
}
}
if _, ok := a.Plan.(*plannercore.Analyze); ok && ctx.GetSessionVars().InRestrictedSQL {
ctx.GetSessionVars().StmtCtx.Priority = kv.PriorityLow
}
b := newExecutorBuilder(ctx, a.InfoSchema)
e := b.build(a.Plan)
if b.err != nil {
return nil, errors.Trace(b.err)
}
// ExecuteExec is not a real Executor, we only use it to build another Executor from a prepared statement.
if executorExec, ok := e.(*ExecuteExec); ok {
err := executorExec.Build()
if err != nil {
return nil, errors.Trace(err)
}
a.Text = executorExec.stmt.Text()
a.isPreparedStmt = true
a.Plan = executorExec.plan
e = executorExec.stmtExec
}
return e, nil
}
// QueryReplacer replaces new line and tab for grep result including query string.
var QueryReplacer = strings.NewReplacer("\r", " ", "\n", " ", "\t", " ")
// LogSlowQuery is used to print the slow query in the log files.
func (a *ExecStmt) LogSlowQuery(txnTS uint64, succ bool) {
level := log.GetLevel()
if level < log.WarnLevel {
return
}
cfg := config.GetGlobalConfig()
costTime := time.Since(a.StartTime)
threshold := time.Duration(cfg.Log.SlowThreshold) * time.Millisecond
if costTime < threshold && level < log.DebugLevel {
return
}
sql := a.Text
if len(sql) > int(cfg.Log.QueryLogMaxLen) {
sql = fmt.Sprintf("%.*q(len:%d)", cfg.Log.QueryLogMaxLen, sql, len(a.Text))
}
sql = QueryReplacer.Replace(sql)
sessVars := a.Ctx.GetSessionVars()
connID := sessVars.ConnectionID
currentDB := sessVars.CurrentDB
var tableIDs, indexIDs string
if len(sessVars.StmtCtx.TableIDs) > 0 {
tableIDs = strings.Replace(fmt.Sprintf("table_ids:%v ", a.Ctx.GetSessionVars().StmtCtx.TableIDs), " ", ",", -1)
}
if len(sessVars.StmtCtx.IndexIDs) > 0 {
indexIDs = strings.Replace(fmt.Sprintf("index_ids:%v ", a.Ctx.GetSessionVars().StmtCtx.IndexIDs), " ", ",", -1)
}
user := sessVars.User
var internal string
if sessVars.InRestrictedSQL {
internal = "[INTERNAL] "
}
execDetail := sessVars.StmtCtx.GetExecDetails()
if costTime < threshold {
logutil.SlowQueryLogger.Debugf(
"[QUERY] %vcost_time:%v %s succ:%v con:%v user:%s txn_start_ts:%v database:%v %v%vsql:%v",
internal, costTime, execDetail, succ, connID, user, txnTS, currentDB, tableIDs, indexIDs, sql)
} else {
logutil.SlowQueryLogger.Warnf(
"[SLOW_QUERY] %vcost_time:%v %s succ:%v con:%v user:%s txn_start_ts:%v database:%v %v%vsql:%v",
internal, costTime, execDetail, succ, connID, user, txnTS, currentDB, tableIDs, indexIDs, sql)
metrics.TotalQueryProcHistogram.Observe(costTime.Seconds())
metrics.TotalCopProcHistogram.Observe(execDetail.ProcessTime.Seconds())
metrics.TotalCopWaitHistogram.Observe(execDetail.WaitTime.Seconds())
var userString string
if user != nil {
userString = user.String()
}
if len(tableIDs) > 10 {
tableIDs = tableIDs[10 : len(tableIDs)-1] // Remove "table_ids:" and the last ","
}
if len(indexIDs) > 10 {
indexIDs = indexIDs[10 : len(indexIDs)-1] // Remove "index_ids:" and the last ","
}
domain.GetDomain(a.Ctx).LogSlowQuery(&domain.SlowQueryInfo{
SQL: sql,
Start: a.StartTime,
Duration: costTime,
Detail: sessVars.StmtCtx.GetExecDetails(),
Succ: succ,
ConnID: connID,
TxnTS: txnTS,
User: userString,
DB: currentDB,
TableIDs: tableIDs,
IndexIDs: indexIDs,
Internal: sessVars.InRestrictedSQL,
})
}
}
// IsPointGetWithPKOrUniqueKeyByAutoCommit returns true when meets following conditions:
// 1. ctx is auto commit tagged
// 2. txn is nil
// 2. plan is point get by pk or unique key
func IsPointGetWithPKOrUniqueKeyByAutoCommit(ctx sessionctx.Context, p plannercore.Plan) bool {
// check auto commit
if !ctx.GetSessionVars().IsAutocommit() {
return false
}
// check txn
if ctx.Txn() != nil {
return false
}
// check plan
if proj, ok := p.(*plannercore.PhysicalProjection); ok {
if len(proj.Children()) != 1 {
return false
}
p = proj.Children()[0]
}
switch v := p.(type) {
case *plannercore.PhysicalIndexReader:
indexScan := v.IndexPlans[0].(*plannercore.PhysicalIndexScan)
return indexScan.IsPointGetByUniqueKey(ctx.GetSessionVars().StmtCtx)
case *plannercore.PhysicalIndexLookUpReader:
indexScan := v.IndexPlans[0].(*plannercore.PhysicalIndexScan)
return indexScan.IsPointGetByUniqueKey(ctx.GetSessionVars().StmtCtx)
case *plannercore.PhysicalTableReader:
tableScan := v.TablePlans[0].(*plannercore.PhysicalTableScan)
return len(tableScan.Ranges) == 1 && tableScan.Ranges[0].IsPoint(ctx.GetSessionVars().StmtCtx)
case *plannercore.PointGetPlan:
return true
default:
return false
}
}