Files
tidb/executor/analyze.go
2019-03-14 15:14:38 +08:00

384 lines
11 KiB
Go

// Copyright 2017 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"
"runtime"
"strconv"
"github.com/pingcap/errors"
"github.com/pingcap/parser/model"
"github.com/pingcap/parser/mysql"
"github.com/pingcap/tidb/distsql"
"github.com/pingcap/tidb/domain"
"github.com/pingcap/tidb/metrics"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/statistics"
"github.com/pingcap/tidb/tablecodec"
"github.com/pingcap/tidb/util/chunk"
"github.com/pingcap/tidb/util/logutil"
"github.com/pingcap/tidb/util/ranger"
"github.com/pingcap/tipb/go-tipb"
"go.uber.org/zap"
)
var _ Executor = &AnalyzeExec{}
// AnalyzeExec represents Analyze executor.
type AnalyzeExec struct {
baseExecutor
tasks []*analyzeTask
}
const (
maxSampleSize = 10000
maxRegionSampleSize = 1000
maxSketchSize = 10000
defaultCMSketchDepth = 5
defaultCMSketchWidth = 2048
)
// Next implements the Executor Next interface.
func (e *AnalyzeExec) Next(ctx context.Context, req *chunk.RecordBatch) error {
concurrency, err := getBuildStatsConcurrency(e.ctx)
if err != nil {
return errors.Trace(err)
}
taskCh := make(chan *analyzeTask, len(e.tasks))
resultCh := make(chan statistics.AnalyzeResult, len(e.tasks))
for i := 0; i < concurrency; i++ {
go e.analyzeWorker(taskCh, resultCh)
}
for _, task := range e.tasks {
taskCh <- task
}
close(taskCh)
statsHandle := domain.GetDomain(e.ctx).StatsHandle()
for i, panicCnt := 0, 0; i < len(e.tasks) && panicCnt < concurrency; i++ {
result := <-resultCh
if result.Err != nil {
err = result.Err
if errors.Trace(err) == errAnalyzeWorkerPanic {
panicCnt++
} else {
logutil.Logger(ctx).Error("analyze failed", zap.Error(err))
}
continue
}
for i, hg := range result.Hist {
err1 := statsHandle.SaveStatsToStorage(result.PhysicalTableID, result.Count, result.IsIndex, hg, result.Cms[i], 1)
if err1 != nil {
err = err1
logutil.Logger(ctx).Error("save stats to storage failed", zap.Error(err))
continue
}
}
}
if err != nil {
return errors.Trace(err)
}
return errors.Trace(statsHandle.Update(GetInfoSchema(e.ctx)))
}
func getBuildStatsConcurrency(ctx sessionctx.Context) (int, error) {
sessionVars := ctx.GetSessionVars()
concurrency, err := variable.GetSessionSystemVar(sessionVars, variable.TiDBBuildStatsConcurrency)
if err != nil {
return 0, errors.Trace(err)
}
c, err := strconv.ParseInt(concurrency, 10, 64)
return int(c), errors.Trace(err)
}
type taskType int
const (
colTask taskType = iota
idxTask
)
type analyzeTask struct {
taskType taskType
idxExec *AnalyzeIndexExec
colExec *AnalyzeColumnsExec
}
var errAnalyzeWorkerPanic = errors.New("analyze worker panic")
func (e *AnalyzeExec) analyzeWorker(taskCh <-chan *analyzeTask, resultCh chan<- statistics.AnalyzeResult) {
defer func() {
if r := recover(); r != nil {
buf := make([]byte, 4096)
stackSize := runtime.Stack(buf, false)
buf = buf[:stackSize]
logutil.Logger(context.Background()).Error("analyze worker panicked", zap.String("stack", string(buf)))
metrics.PanicCounter.WithLabelValues(metrics.LabelAnalyze).Inc()
resultCh <- statistics.AnalyzeResult{
Err: errAnalyzeWorkerPanic,
}
}
}()
for task := range taskCh {
switch task.taskType {
case colTask:
resultCh <- analyzeColumnsPushdown(task.colExec)
case idxTask:
resultCh <- analyzeIndexPushdown(task.idxExec)
}
}
}
func analyzeIndexPushdown(idxExec *AnalyzeIndexExec) statistics.AnalyzeResult {
hist, cms, err := idxExec.buildStats()
if err != nil {
return statistics.AnalyzeResult{Err: err}
}
result := statistics.AnalyzeResult{
PhysicalTableID: idxExec.physicalTableID,
Hist: []*statistics.Histogram{hist},
Cms: []*statistics.CMSketch{cms},
IsIndex: 1,
}
if hist.Len() > 0 {
result.Count = hist.Buckets[hist.Len()-1].Count
}
return result
}
// AnalyzeIndexExec represents analyze index push down executor.
type AnalyzeIndexExec struct {
ctx sessionctx.Context
physicalTableID int64
idxInfo *model.IndexInfo
concurrency int
priority int
analyzePB *tipb.AnalyzeReq
result distsql.SelectResult
maxNumBuckets uint64
}
func (e *AnalyzeIndexExec) open() error {
var builder distsql.RequestBuilder
kvReq, err := builder.SetIndexRanges(e.ctx.GetSessionVars().StmtCtx, e.physicalTableID, e.idxInfo.ID, ranger.FullRange()).
SetAnalyzeRequest(e.analyzePB).
SetKeepOrder(true).
SetConcurrency(e.concurrency).
Build()
if err != nil {
return errors.Trace(err)
}
ctx := context.TODO()
e.result, err = distsql.Analyze(ctx, e.ctx.GetClient(), kvReq, e.ctx.GetSessionVars().KVVars, e.ctx.GetSessionVars().InRestrictedSQL)
if err != nil {
return errors.Trace(err)
}
e.result.Fetch(ctx)
return nil
}
func (e *AnalyzeIndexExec) buildStats() (hist *statistics.Histogram, cms *statistics.CMSketch, err error) {
if err = e.open(); err != nil {
return nil, nil, errors.Trace(err)
}
defer func() {
if err1 := e.result.Close(); err1 != nil {
hist = nil
cms = nil
err = errors.Trace(err1)
}
}()
hist = &statistics.Histogram{}
cms = statistics.NewCMSketch(defaultCMSketchDepth, defaultCMSketchWidth)
for {
data, err := e.result.NextRaw(context.TODO())
if err != nil {
return nil, nil, errors.Trace(err)
}
if data == nil {
break
}
resp := &tipb.AnalyzeIndexResp{}
err = resp.Unmarshal(data)
if err != nil {
return nil, nil, errors.Trace(err)
}
hist, err = statistics.MergeHistograms(e.ctx.GetSessionVars().StmtCtx, hist, statistics.HistogramFromProto(resp.Hist), int(e.maxNumBuckets))
if err != nil {
return nil, nil, errors.Trace(err)
}
if resp.Cms != nil {
err := cms.MergeCMSketch(statistics.CMSketchFromProto(resp.Cms))
if err != nil {
return nil, nil, errors.Trace(err)
}
}
}
hist.ID = e.idxInfo.ID
return hist, cms, nil
}
func analyzeColumnsPushdown(colExec *AnalyzeColumnsExec) statistics.AnalyzeResult {
hists, cms, err := colExec.buildStats()
if err != nil {
return statistics.AnalyzeResult{Err: err}
}
result := statistics.AnalyzeResult{
PhysicalTableID: colExec.physicalTableID,
Hist: hists,
Cms: cms,
}
hist := hists[0]
result.Count = hist.NullCount
if hist.Len() > 0 {
result.Count += hist.Buckets[hist.Len()-1].Count
}
return result
}
// AnalyzeColumnsExec represents Analyze columns push down executor.
type AnalyzeColumnsExec struct {
ctx sessionctx.Context
physicalTableID int64
colsInfo []*model.ColumnInfo
pkInfo *model.ColumnInfo
concurrency int
priority int
analyzePB *tipb.AnalyzeReq
resultHandler *tableResultHandler
maxNumBuckets uint64
}
func (e *AnalyzeColumnsExec) open() error {
var ranges []*ranger.Range
if e.pkInfo != nil {
ranges = ranger.FullIntRange(mysql.HasUnsignedFlag(e.pkInfo.Flag))
} else {
ranges = ranger.FullIntRange(false)
}
e.resultHandler = &tableResultHandler{}
firstPartRanges, secondPartRanges := splitRanges(ranges, true)
firstResult, err := e.buildResp(firstPartRanges)
if err != nil {
return errors.Trace(err)
}
if len(secondPartRanges) == 0 {
e.resultHandler.open(nil, firstResult)
return nil
}
var secondResult distsql.SelectResult
secondResult, err = e.buildResp(secondPartRanges)
if err != nil {
return errors.Trace(err)
}
e.resultHandler.open(firstResult, secondResult)
return nil
}
func (e *AnalyzeColumnsExec) buildResp(ranges []*ranger.Range) (distsql.SelectResult, error) {
var builder distsql.RequestBuilder
// Always set KeepOrder of the request to be true, in order to compute
// correct `correlation` of columns.
kvReq, err := builder.SetTableRanges(e.physicalTableID, ranges, nil).
SetAnalyzeRequest(e.analyzePB).
SetKeepOrder(true).
SetConcurrency(e.concurrency).
Build()
if err != nil {
return nil, errors.Trace(err)
}
ctx := context.TODO()
result, err := distsql.Analyze(ctx, e.ctx.GetClient(), kvReq, e.ctx.GetSessionVars().KVVars, e.ctx.GetSessionVars().InRestrictedSQL)
if err != nil {
return nil, errors.Trace(err)
}
result.Fetch(ctx)
return result, nil
}
func (e *AnalyzeColumnsExec) buildStats() (hists []*statistics.Histogram, cms []*statistics.CMSketch, err error) {
if err = e.open(); err != nil {
return nil, nil, errors.Trace(err)
}
defer func() {
if err1 := e.resultHandler.Close(); err1 != nil {
hists = nil
cms = nil
err = errors.Trace(err1)
}
}()
pkHist := &statistics.Histogram{}
collectors := make([]*statistics.SampleCollector, len(e.colsInfo))
for i := range collectors {
collectors[i] = &statistics.SampleCollector{
IsMerger: true,
FMSketch: statistics.NewFMSketch(maxSketchSize),
MaxSampleSize: maxSampleSize,
CMSketch: statistics.NewCMSketch(defaultCMSketchDepth, defaultCMSketchWidth),
}
}
for {
data, err1 := e.resultHandler.nextRaw(context.TODO())
if err1 != nil {
return nil, nil, errors.Trace(err1)
}
if data == nil {
break
}
resp := &tipb.AnalyzeColumnsResp{}
err = resp.Unmarshal(data)
if err != nil {
return nil, nil, errors.Trace(err)
}
sc := e.ctx.GetSessionVars().StmtCtx
if e.pkInfo != nil {
pkHist, err = statistics.MergeHistograms(sc, pkHist, statistics.HistogramFromProto(resp.PkHist), int(e.maxNumBuckets))
if err != nil {
return nil, nil, errors.Trace(err)
}
}
for i, rc := range resp.Collectors {
collectors[i].MergeSampleCollector(sc, statistics.SampleCollectorFromProto(rc))
}
}
timeZone := e.ctx.GetSessionVars().Location()
if e.pkInfo != nil {
pkHist.ID = e.pkInfo.ID
err = pkHist.DecodeTo(&e.pkInfo.FieldType, timeZone)
if err != nil {
return nil, nil, errors.Trace(err)
}
hists = append(hists, pkHist)
cms = append(cms, nil)
}
for i, col := range e.colsInfo {
for j, s := range collectors[i].Samples {
collectors[i].Samples[j].Ordinal = j
collectors[i].Samples[j].Value, err = tablecodec.DecodeColumnValue(s.Value.GetBytes(), &col.FieldType, timeZone)
if err != nil {
return nil, nil, errors.Trace(err)
}
}
hg, err := statistics.BuildColumn(e.ctx, int64(e.maxNumBuckets), col.ID, collectors[i], &col.FieldType)
if err != nil {
return nil, nil, errors.Trace(err)
}
hists = append(hists, hg)
cms = append(cms, collectors[i].CMSketch)
}
return hists, cms, nil
}