Files
tidb/distsql/select_result.go
SunRunAway 1f57a538a4 distsql: make CopStream available (#11311)
All tests passed, auto merged by Bot
2019-07-30 17:10:52 +08:00

266 lines
7.0 KiB
Go

// Copyright 2018 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 distsql
import (
"context"
"fmt"
"time"
"github.com/pingcap/errors"
"github.com/pingcap/parser/terror"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/metrics"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/statistics"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/chunk"
"github.com/pingcap/tidb/util/codec"
"github.com/pingcap/tidb/util/logutil"
"github.com/pingcap/tidb/util/memory"
"github.com/pingcap/tipb/go-tipb"
"go.uber.org/zap"
)
var (
_ SelectResult = (*selectResult)(nil)
_ SelectResult = (*streamResult)(nil)
)
// SelectResult is an iterator of coprocessor partial results.
type SelectResult interface {
// Fetch fetches partial results from client.
Fetch(context.Context)
// NextRaw gets the next raw result.
NextRaw(context.Context) ([]byte, error)
// Next reads the data into chunk.
Next(context.Context, *chunk.Chunk) error
// Close closes the iterator.
Close() error
}
type resultWithErr struct {
result kv.ResultSubset
err error
}
type selectResult struct {
label string
resp kv.Response
results chan resultWithErr
closed chan struct{}
rowLen int
fieldTypes []*types.FieldType
ctx sessionctx.Context
selectResp *tipb.SelectResponse
selectRespSize int // record the selectResp.Size() when it is initialized.
respChkIdx int
feedback *statistics.QueryFeedback
partialCount int64 // number of partial results.
sqlType string
// copPlanIDs contains all copTasks' planIDs,
// which help to collect copTasks' runtime stats.
copPlanIDs []fmt.Stringer
memTracker *memory.Tracker
}
func (r *selectResult) Fetch(ctx context.Context) {
go r.fetch(ctx)
}
func (r *selectResult) fetch(ctx context.Context) {
startTime := time.Now()
defer func() {
if c := recover(); c != nil {
err := fmt.Errorf("%v", c)
logutil.Logger(ctx).Error("OOM", zap.Error(err))
r.results <- resultWithErr{err: err}
}
close(r.results)
duration := time.Since(startTime)
// TODO: Add a label to distinguish between success or failure.
// https://github.com/pingcap/tidb/issues/11397
metrics.DistSQLQueryHistgram.WithLabelValues(r.label, r.sqlType).Observe(duration.Seconds())
}()
for {
var result resultWithErr
resultSubset, err := r.resp.Next(ctx)
if err != nil {
result.err = err
} else if resultSubset == nil {
// If the result is drained, the resultSubset would be nil
return
} else {
result.result = resultSubset
r.memConsume(int64(resultSubset.MemSize()))
}
select {
case r.results <- result:
case <-r.closed:
// If selectResult called Close() already, make fetch goroutine exit.
if resultSubset != nil {
r.memConsume(-int64(resultSubset.MemSize()))
}
return
case <-ctx.Done():
if resultSubset != nil {
r.memConsume(-int64(resultSubset.MemSize()))
}
return
}
}
}
// NextRaw returns the next raw partial result.
func (r *selectResult) NextRaw(ctx context.Context) (data []byte, err error) {
re := <-r.results
r.partialCount++
r.feedback.Invalidate()
if re.result != nil && re.err == nil {
data = re.result.GetData()
}
return data, re.err
}
// Next reads data to the chunk.
func (r *selectResult) Next(ctx context.Context, chk *chunk.Chunk) error {
chk.Reset()
for !chk.IsFull() {
if r.selectResp == nil || r.respChkIdx == len(r.selectResp.Chunks) {
err := r.getSelectResp()
if err != nil || r.selectResp == nil {
return err
}
}
err := r.readRowsData(chk)
if err != nil {
return err
}
if len(r.selectResp.Chunks[r.respChkIdx].RowsData) == 0 {
r.respChkIdx++
}
}
return nil
}
func (r *selectResult) getSelectResp() error {
r.respChkIdx = 0
for {
re := <-r.results
if re.err != nil {
return errors.Trace(re.err)
}
if r.selectResp != nil {
r.memConsume(-int64(r.selectRespSize))
}
if re.result == nil {
r.selectResp = nil
return nil
}
r.memConsume(-int64(re.result.MemSize()))
r.selectResp = new(tipb.SelectResponse)
err := r.selectResp.Unmarshal(re.result.GetData())
if err != nil {
return errors.Trace(err)
}
r.selectRespSize = r.selectResp.Size()
r.memConsume(int64(r.selectRespSize))
if err := r.selectResp.Error; err != nil {
return terror.ClassTiKV.New(terror.ErrCode(err.Code), err.Msg)
}
sc := r.ctx.GetSessionVars().StmtCtx
for _, warning := range r.selectResp.Warnings {
sc.AppendWarning(terror.ClassTiKV.New(terror.ErrCode(warning.Code), warning.Msg))
}
r.updateCopRuntimeStats(re.result.GetExecDetails().CalleeAddress)
r.feedback.Update(re.result.GetStartKey(), r.selectResp.OutputCounts)
r.partialCount++
sc.MergeExecDetails(re.result.GetExecDetails(), nil)
if len(r.selectResp.Chunks) == 0 {
continue
}
return nil
}
}
func (r *selectResult) updateCopRuntimeStats(callee string) {
if r.ctx.GetSessionVars().StmtCtx.RuntimeStatsColl == nil || callee == "" {
return
}
if len(r.selectResp.GetExecutionSummaries()) != len(r.copPlanIDs) {
logutil.BgLogger().Error("invalid cop task execution summaries length",
zap.Int("expected", len(r.copPlanIDs)),
zap.Int("received", len(r.selectResp.GetExecutionSummaries())))
return
}
for i, detail := range r.selectResp.GetExecutionSummaries() {
if detail != nil && detail.TimeProcessedNs != nil &&
detail.NumProducedRows != nil && detail.NumIterations != nil {
planID := r.copPlanIDs[i]
r.ctx.GetSessionVars().StmtCtx.RuntimeStatsColl.
RecordOneCopTask(planID.String(), callee, detail)
}
}
}
func (r *selectResult) readRowsData(chk *chunk.Chunk) (err error) {
rowsData := r.selectResp.Chunks[r.respChkIdx].RowsData
decoder := codec.NewDecoder(chk, r.ctx.GetSessionVars().Location())
for !chk.IsFull() && len(rowsData) > 0 {
for i := 0; i < r.rowLen; i++ {
rowsData, err = decoder.DecodeOne(rowsData, i, r.fieldTypes[i])
if err != nil {
return err
}
}
}
r.selectResp.Chunks[r.respChkIdx].RowsData = rowsData
return nil
}
func (r *selectResult) memConsume(bytes int64) {
if r.memTracker != nil {
r.memTracker.Consume(bytes)
}
}
// Close closes selectResult.
func (r *selectResult) Close() error {
if r.feedback.Actual() >= 0 {
metrics.DistSQLScanKeysHistogram.Observe(float64(r.feedback.Actual()))
}
metrics.DistSQLPartialCountHistogram.Observe(float64(r.partialCount))
// Close this channel to tell the fetch goroutine to exit.
close(r.closed)
for re := range r.results {
if re.result != nil {
r.memConsume(-int64(re.result.MemSize()))
}
}
if r.selectResp != nil {
r.memConsume(-int64(r.selectRespSize))
}
return r.resp.Close()
}