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// Copyright 2019 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"
"hash"
"hash/fnv"
"runtime/trace"
"sync"
"sync/atomic"
"time"
"github.com/pingcap/errors"
"github.com/pingcap/failpoint"
"github.com/pingcap/tidb/expression"
plannercore "github.com/pingcap/tidb/planner/core"
"github.com/pingcap/tidb/util"
"github.com/pingcap/tidb/util/chunk"
"github.com/pingcap/tidb/util/codec"
"github.com/pingcap/tidb/util/memory"
"github.com/pingcap/tidb/util/ranger"
)
// numResChkHold indicates the number of resource chunks that an inner worker
// holds at the same time.
// It's used in 2 cases individually:
// 1. IndexMergeJoin
// 2. IndexNestedLoopHashJoin:
// It's used when IndexNestedLoopHashJoin.keepOuterOrder is true.
// Otherwise, there will be at most `concurrency` resource chunks throughout
// the execution of IndexNestedLoopHashJoin.
const numResChkHold = 4
// IndexNestedLoopHashJoin employs one outer worker and N inner workers to
// execute concurrently. The output order is not promised.
//
// The execution flow is very similar to IndexLookUpReader:
// 1. The outer worker reads N outer rows, builds a task and sends it to the
// inner worker channel.
// 2. The inner worker receives the tasks and does 3 things for every task:
// 1. builds hash table from the outer rows
// 2. builds key ranges from outer rows and fetches inner rows
// 3. probes the hash table and sends the join result to the main thread channel.
// Note: step 1 and step 2 runs concurrently.
//
// 3. The main thread receives the join results.
type IndexNestedLoopHashJoin struct {
IndexLookUpJoin
resultCh chan *indexHashJoinResult
joinChkResourceCh []chan *chunk.Chunk
// We build individual joiner for each inner worker when using chunk-based
// execution, to avoid the concurrency of joiner.chk and joiner.selected.
joiners []joiner
keepOuterOrder bool
curTask *indexHashJoinTask
// taskCh is only used when `keepOuterOrder` is true.
taskCh chan *indexHashJoinTask
stats *indexLookUpJoinRuntimeStats
}
type indexHashJoinOuterWorker struct {
outerWorker
innerCh chan *indexHashJoinTask
keepOuterOrder bool
// taskCh is only used when the outer order needs to be promised.
taskCh chan *indexHashJoinTask
}
type indexHashJoinInnerWorker struct {
innerWorker
matchedOuterPtrs []chunk.RowPtr
joiner joiner
joinChkResourceCh chan *chunk.Chunk
// resultCh is valid only when indexNestedLoopHashJoin do not need to keep
// order. Otherwise, it will be nil.
resultCh chan *indexHashJoinResult
taskCh <-chan *indexHashJoinTask
wg *sync.WaitGroup
joinKeyBuf []byte
outerRowStatus []outerRowStatusFlag
}
type indexHashJoinResult struct {
chk *chunk.Chunk
err error
src chan<- *chunk.Chunk
}
type indexHashJoinTask struct {
*lookUpJoinTask
outerRowStatus [][]outerRowStatusFlag
lookupMap *rowHashMap
err error
keepOuterOrder bool
// resultCh is only used when the outer order needs to be promised.
resultCh chan *indexHashJoinResult
// matchedInnerRowPtrs is only valid when the outer order needs to be
// promised. Otherwise, it will be nil.
// len(matchedInnerRowPtrs) equals to
// lookUpJoinTask.outerResult.NumChunks(), and the elements of every
// matchedInnerRowPtrs[chkIdx][rowIdx] indicates the matched inner row ptrs
// of the corresponding outer row.
matchedInnerRowPtrs [][][]chunk.RowPtr
}
// Open implements the IndexNestedLoopHashJoin Executor interface.
func (e *IndexNestedLoopHashJoin) Open(ctx context.Context) error {
// Be careful, very dirty hack in this line!!!
// IndexLookUpJoin need to rebuild executor (the dataReaderBuilder) during
// executing. However `executor.Next()` is lazy evaluation when the RecordSet
// result is drained.
// Lazy evaluation means the saved session context may change during executor's
// building and its running.
// A specific sequence for example:
//
// e := buildExecutor() // txn at build time
// recordSet := runStmt(e)
// session.CommitTxn() // txn closed
// recordSet.Next()
// e.dataReaderBuilder.Build() // txn is used again, which is already closed
//
// The trick here is `getSnapshotTS` will cache snapshot ts in the dataReaderBuilder,
// so even txn is destroyed later, the dataReaderBuilder could still use the
// cached snapshot ts to construct DAG.
_, err := e.innerCtx.readerBuilder.getSnapshotTS()
if err != nil {
return err
}
err = e.children[0].Open(ctx)
if err != nil {
return err
}
e.memTracker = memory.NewTracker(e.id, -1)
e.memTracker.AttachTo(e.ctx.GetSessionVars().StmtCtx.MemTracker)
e.innerPtrBytes = make([][]byte, 0, 8)
if e.runtimeStats != nil {
e.stats = &indexLookUpJoinRuntimeStats{}
e.ctx.GetSessionVars().StmtCtx.RuntimeStatsColl.RegisterStats(e.id, e.stats)
}
e.startWorkers(ctx)
return nil
}
func (e *IndexNestedLoopHashJoin) startWorkers(ctx context.Context) {
concurrency := e.ctx.GetSessionVars().IndexLookupJoinConcurrency
if e.stats != nil {
e.stats.concurrency = concurrency
}
workerCtx, cancelFunc := context.WithCancel(ctx)
e.cancelFunc = cancelFunc
innerCh := make(chan *indexHashJoinTask, concurrency)
if e.keepOuterOrder {
e.taskCh = make(chan *indexHashJoinTask, concurrency)
}
e.workerWg.Add(1)
ow := e.newOuterWorker(innerCh)
go util.WithRecovery(func() { ow.run(workerCtx) }, e.finishJoinWorkers)
if !e.keepOuterOrder {
e.resultCh = make(chan *indexHashJoinResult, concurrency)
} else {
// When `keepOuterOrder` is true, each task holds their own `resultCh`
// individually, thus we do not need a global resultCh.
e.resultCh = nil
}
e.joinChkResourceCh = make([]chan *chunk.Chunk, concurrency)
for i := int(0); i < concurrency; i++ {
if !e.keepOuterOrder {
e.joinChkResourceCh[i] = make(chan *chunk.Chunk, 1)
e.joinChkResourceCh[i] <- newFirstChunk(e)
} else {
e.joinChkResourceCh[i] = make(chan *chunk.Chunk, numResChkHold)
for j := 0; j < numResChkHold; j++ {
e.joinChkResourceCh[i] <- newFirstChunk(e)
}
}
}
e.workerWg.Add(concurrency)
for i := int(0); i < concurrency; i++ {
workerID := i
go util.WithRecovery(func() { e.newInnerWorker(innerCh, workerID).run(workerCtx, cancelFunc) }, e.finishJoinWorkers)
}
go e.wait4JoinWorkers()
}
func (e *IndexNestedLoopHashJoin) finishJoinWorkers(r interface{}) {
if r != nil {
err := errors.New(fmt.Sprintf("%v", r))
if !e.keepOuterOrder {
e.resultCh <- &indexHashJoinResult{err: err}
} else {
task := &indexHashJoinTask{err: err}
e.taskCh <- task
}
if e.cancelFunc != nil {
e.cancelFunc()
}
}
e.workerWg.Done()
}
func (e *IndexNestedLoopHashJoin) wait4JoinWorkers() {
e.workerWg.Wait()
if e.resultCh != nil {
close(e.resultCh)
}
if e.taskCh != nil {
close(e.taskCh)
}
}
// Next implements the IndexNestedLoopHashJoin Executor interface.
func (e *IndexNestedLoopHashJoin) Next(ctx context.Context, req *chunk.Chunk) error {
req.Reset()
if e.keepOuterOrder {
return e.runInOrder(ctx, req)
}
// unordered run
var (
result *indexHashJoinResult
ok bool
)
select {
case result, ok = <-e.resultCh:
if !ok {
return nil
}
if result.err != nil {
return result.err
}
case <-ctx.Done():
return ctx.Err()
}
req.SwapColumns(result.chk)
result.src <- result.chk
return nil
}
func (e *IndexNestedLoopHashJoin) runInOrder(ctx context.Context, req *chunk.Chunk) error {
var (
result *indexHashJoinResult
ok bool
)
for {
if e.isDryUpTasks(ctx) {
return nil
}
if e.curTask.err != nil {
return e.curTask.err
}
select {
case result, ok = <-e.curTask.resultCh:
if !ok {
e.curTask = nil
continue
}
if result.err != nil {
return result.err
}
case <-ctx.Done():
return ctx.Err()
}
req.SwapColumns(result.chk)
result.src <- result.chk
return nil
}
}
// isDryUpTasks indicates whether all the tasks have been processed.
func (e *IndexNestedLoopHashJoin) isDryUpTasks(ctx context.Context) bool {
if e.curTask != nil {
return false
}
var ok bool
select {
case e.curTask, ok = <-e.taskCh:
if !ok {
return true
}
case <-ctx.Done():
return true
}
return false
}
// Close implements the IndexNestedLoopHashJoin Executor interface.
func (e *IndexNestedLoopHashJoin) Close() error {
if e.cancelFunc != nil {
e.cancelFunc()
e.cancelFunc = nil
}
if e.resultCh != nil {
for range e.resultCh {
}
e.resultCh = nil
}
if e.taskCh != nil {
for range e.taskCh {
}
e.taskCh = nil
}
for i := range e.joinChkResourceCh {
close(e.joinChkResourceCh[i])
}
e.joinChkResourceCh = nil
return e.baseExecutor.Close()
}
func (ow *indexHashJoinOuterWorker) run(ctx context.Context) {
defer trace.StartRegion(ctx, "IndexHashJoinOuterWorker").End()
defer close(ow.innerCh)
for {
task, err := ow.buildTask(ctx)
failpoint.Inject("testIndexHashJoinOuterWorkerErr", func() {
err = errors.New("mockIndexHashJoinOuterWorkerErr")
})
if err != nil {
task = &indexHashJoinTask{err: err}
if ow.keepOuterOrder {
task.keepOuterOrder, task.resultCh = true, make(chan *indexHashJoinResult, 1)
ow.pushToChan(ctx, task, ow.taskCh)
}
ow.pushToChan(ctx, task, ow.innerCh)
return
}
if task == nil {
return
}
if finished := ow.pushToChan(ctx, task, ow.innerCh); finished {
return
}
if ow.keepOuterOrder {
failpoint.Inject("testIssue20779", func() {
panic("testIssue20779")
})
if finished := ow.pushToChan(ctx, task, ow.taskCh); finished {
return
}
}
}
}
func (ow *indexHashJoinOuterWorker) buildTask(ctx context.Context) (*indexHashJoinTask, error) {
task, err := ow.outerWorker.buildTask(ctx)
if task == nil || err != nil {
return nil, err
}
var (
resultCh chan *indexHashJoinResult
matchedInnerRowPtrs [][][]chunk.RowPtr
)
if ow.keepOuterOrder {
resultCh = make(chan *indexHashJoinResult, numResChkHold)
matchedInnerRowPtrs = make([][][]chunk.RowPtr, task.outerResult.NumChunks())
for i := range matchedInnerRowPtrs {
matchedInnerRowPtrs[i] = make([][]chunk.RowPtr, task.outerResult.GetChunk(i).NumRows())
}
}
numChks := task.outerResult.NumChunks()
outerRowStatus := make([][]outerRowStatusFlag, numChks)
for i := 0; i < numChks; i++ {
outerRowStatus[i] = make([]outerRowStatusFlag, task.outerResult.GetChunk(i).NumRows())
}
return &indexHashJoinTask{
lookUpJoinTask: task,
outerRowStatus: outerRowStatus,
keepOuterOrder: ow.keepOuterOrder,
resultCh: resultCh,
matchedInnerRowPtrs: matchedInnerRowPtrs,
}, nil
}
func (ow *indexHashJoinOuterWorker) pushToChan(ctx context.Context, task *indexHashJoinTask, dst chan<- *indexHashJoinTask) bool {
select {
case <-ctx.Done():
return true
case dst <- task:
}
return false
}
func (e *IndexNestedLoopHashJoin) newOuterWorker(innerCh chan *indexHashJoinTask) *indexHashJoinOuterWorker {
ow := &indexHashJoinOuterWorker{
outerWorker: outerWorker{
outerCtx: e.outerCtx,
ctx: e.ctx,
executor: e.children[0],
batchSize: 32,
maxBatchSize: e.ctx.GetSessionVars().IndexJoinBatchSize,
parentMemTracker: e.memTracker,
lookup: &e.IndexLookUpJoin,
},
innerCh: innerCh,
keepOuterOrder: e.keepOuterOrder,
taskCh: e.taskCh,
}
return ow
}
func (e *IndexNestedLoopHashJoin) newInnerWorker(taskCh chan *indexHashJoinTask, workerID int) *indexHashJoinInnerWorker {
// Since multiple inner workers run concurrently, we should copy join's indexRanges for every worker to avoid data race.
copiedRanges := make([]*ranger.Range, 0, len(e.indexRanges))
for _, ran := range e.indexRanges {
copiedRanges = append(copiedRanges, ran.Clone())
}
var innerStats *innerWorkerRuntimeStats
if e.stats != nil {
innerStats = &e.stats.innerWorker
}
iw := &indexHashJoinInnerWorker{
innerWorker: innerWorker{
innerCtx: e.innerCtx,
outerCtx: e.outerCtx,
ctx: e.ctx,
executorChk: chunk.NewChunkWithCapacity(e.innerCtx.rowTypes, e.maxChunkSize),
indexRanges: copiedRanges,
keyOff2IdxOff: e.keyOff2IdxOff,
stats: innerStats,
},
taskCh: taskCh,
joiner: e.joiners[workerID],
joinChkResourceCh: e.joinChkResourceCh[workerID],
resultCh: e.resultCh,
matchedOuterPtrs: make([]chunk.RowPtr, 0, e.maxChunkSize),
joinKeyBuf: make([]byte, 1),
outerRowStatus: make([]outerRowStatusFlag, 0, e.maxChunkSize),
}
if e.lastColHelper != nil {
// nextCwf.TmpConstant needs to be reset for every individual
// inner worker to avoid data race when the inner workers is running
// concurrently.
nextCwf := *e.lastColHelper
nextCwf.TmpConstant = make([]*expression.Constant, len(e.lastColHelper.TmpConstant))
for i := range e.lastColHelper.TmpConstant {
nextCwf.TmpConstant[i] = &expression.Constant{RetType: nextCwf.TargetCol.RetType}
}
iw.nextColCompareFilters = &nextCwf
}
return iw
}
func (iw *indexHashJoinInnerWorker) run(ctx context.Context, cancelFunc context.CancelFunc) {
defer trace.StartRegion(ctx, "IndexHashJoinInnerWorker").End()
var task *indexHashJoinTask
joinResult, ok := iw.getNewJoinResult(ctx)
if !ok {
cancelFunc()
return
}
h, resultCh := fnv.New64(), iw.resultCh
for {
select {
case <-ctx.Done():
return
case task, ok = <-iw.taskCh:
}
if !ok {
break
}
// We need to init resultCh before the err is returned.
if task.keepOuterOrder {
resultCh = task.resultCh
}
if task.err != nil {
joinResult.err = task.err
break
}
err := iw.handleTask(ctx, task, joinResult, h, resultCh)
if err != nil {
joinResult.err = err
break
}
if task.keepOuterOrder {
// We need to get a new result holder here because the old
// `joinResult` hash been sent to the `resultCh` or to the
// `joinChkResourceCh`.
joinResult, ok = iw.getNewJoinResult(ctx)
if !ok {
cancelFunc()
return
}
}
}
failpoint.Inject("testIndexHashJoinInnerWorkerErr", func() {
joinResult.err = errors.New("mockIndexHashJoinInnerWorkerErr")
})
if joinResult.err != nil {
resultCh <- joinResult
return
}
// When task.keepOuterOrder is TRUE(resultCh != iw.resultCh), the last
// joinResult will be checked when the a task has been processed, thus we do
// not need to check it here again.
if resultCh == iw.resultCh && joinResult.chk != nil && joinResult.chk.NumRows() > 0 {
select {
case resultCh <- joinResult:
case <-ctx.Done():
return
}
}
}
func (iw *indexHashJoinInnerWorker) getNewJoinResult(ctx context.Context) (*indexHashJoinResult, bool) {
joinResult := &indexHashJoinResult{
src: iw.joinChkResourceCh,
}
ok := true
select {
case joinResult.chk, ok = <-iw.joinChkResourceCh:
case <-ctx.Done():
return nil, false
}
return joinResult, ok
}
func (iw *indexHashJoinInnerWorker) buildHashTableForOuterResult(ctx context.Context, task *indexHashJoinTask, h hash.Hash64) {
if iw.stats != nil {
start := time.Now()
defer func() {
atomic.AddInt64(&iw.stats.build, int64(time.Since(start)))
}()
}
buf, numChks := make([]byte, 1), task.outerResult.NumChunks()
task.lookupMap = newRowHashMap(task.outerResult.Len())
for chkIdx := 0; chkIdx < numChks; chkIdx++ {
chk := task.outerResult.GetChunk(chkIdx)
numRows := chk.NumRows()
OUTER:
for rowIdx := 0; rowIdx < numRows; rowIdx++ {
if task.outerMatch != nil && !task.outerMatch[chkIdx][rowIdx] {
continue
}
row := chk.GetRow(rowIdx)
hashColIdx := iw.outerCtx.hashCols
for _, i := range hashColIdx {
if row.IsNull(i) {
continue OUTER
}
}
h.Reset()
err := codec.HashChunkRow(iw.ctx.GetSessionVars().StmtCtx, h, row, iw.outerCtx.rowTypes, hashColIdx, buf)
failpoint.Inject("testIndexHashJoinBuildErr", func() {
err = errors.New("mockIndexHashJoinBuildErr")
})
if err != nil {
// This panic will be recovered by the invoker.
panic(err.Error())
}
rowPtr := chunk.RowPtr{ChkIdx: uint32(chkIdx), RowIdx: uint32(rowIdx)}
task.lookupMap.Put(h.Sum64(), rowPtr)
}
}
}
func (iw *indexHashJoinInnerWorker) fetchInnerResults(ctx context.Context, task *lookUpJoinTask) error {
lookUpContents, err := iw.constructLookupContent(task)
if err != nil {
return err
}
return iw.innerWorker.fetchInnerResults(ctx, task, lookUpContents)
}
func (iw *indexHashJoinInnerWorker) handleHashJoinInnerWorkerPanic(r interface{}) {
if r != nil {
iw.resultCh <- &indexHashJoinResult{err: errors.Errorf("%v", r)}
}
iw.wg.Done()
}
func (iw *indexHashJoinInnerWorker) handleTask(ctx context.Context, task *indexHashJoinTask, joinResult *indexHashJoinResult, h hash.Hash64, resultCh chan *indexHashJoinResult) error {
var joinStartTime time.Time
if iw.stats != nil {
start := time.Now()
defer func() {
endTime := time.Now()
atomic.AddInt64(&iw.stats.totalTime, int64(endTime.Sub(start)))
atomic.AddInt64(&iw.stats.join, int64(endTime.Sub(joinStartTime)))
}()
}
iw.wg = &sync.WaitGroup{}
iw.wg.Add(1)
// TODO(XuHuaiyu): we may always use the smaller side to build the hashtable.
go util.WithRecovery(func() { iw.buildHashTableForOuterResult(ctx, task, h) }, iw.handleHashJoinInnerWorkerPanic)
err := iw.fetchInnerResults(ctx, task.lookUpJoinTask)
if err != nil {
return err
}
iw.wg.Wait()
joinStartTime = time.Now()
if !task.keepOuterOrder {
return iw.doJoinUnordered(ctx, task, joinResult, h, resultCh)
}
return iw.doJoinInOrder(ctx, task, joinResult, h, resultCh)
}
func (iw *indexHashJoinInnerWorker) doJoinUnordered(ctx context.Context, task *indexHashJoinTask, joinResult *indexHashJoinResult, h hash.Hash64, resultCh chan *indexHashJoinResult) error {
var ok bool
iter := chunk.NewIterator4List(task.innerResult)
for row := iter.Begin(); row != iter.End(); row = iter.Next() {
ok, joinResult = iw.joinMatchedInnerRow2Chunk(ctx, row, task, joinResult, h, iw.joinKeyBuf)
if !ok {
return errors.New("indexHashJoinInnerWorker.doJoinUnordered failed")
}
}
for chkIdx, outerRowStatus := range task.outerRowStatus {
chk := task.outerResult.GetChunk(chkIdx)
for rowIdx, val := range outerRowStatus {
if val == outerRowMatched {
continue
}
iw.joiner.onMissMatch(val == outerRowHasNull, chk.GetRow(rowIdx), joinResult.chk)
if joinResult.chk.IsFull() {
select {
case resultCh <- joinResult:
case <-ctx.Done():
return ctx.Err()
}
joinResult, ok = iw.getNewJoinResult(ctx)
if !ok {
return errors.New("indexHashJoinInnerWorker.doJoinUnordered failed")
}
}
}
}
return nil
}
func (iw *indexHashJoinInnerWorker) getMatchedOuterRows(innerRow chunk.Row, task *indexHashJoinTask, h hash.Hash64, buf []byte) (matchedRows []chunk.Row, matchedRowPtr []chunk.RowPtr, err error) {
h.Reset()
err = codec.HashChunkRow(iw.ctx.GetSessionVars().StmtCtx, h, innerRow, iw.rowTypes, iw.hashCols, buf)
if err != nil {
return nil, nil, err
}
iw.matchedOuterPtrs = task.lookupMap.Get(h.Sum64())
if len(iw.matchedOuterPtrs) == 0 {
return nil, nil, nil
}
joinType := JoinerType(iw.joiner)
isSemiJoin := joinType == plannercore.SemiJoin || joinType == plannercore.LeftOuterSemiJoin
matchedRows = make([]chunk.Row, 0, len(iw.matchedOuterPtrs))
matchedRowPtr = make([]chunk.RowPtr, 0, len(iw.matchedOuterPtrs))
for _, ptr := range iw.matchedOuterPtrs {
outerRow := task.outerResult.GetRow(ptr)
ok, err := codec.EqualChunkRow(iw.ctx.GetSessionVars().StmtCtx, innerRow, iw.rowTypes, iw.keyCols, outerRow, iw.outerCtx.rowTypes, iw.outerCtx.hashCols)
if err != nil {
return nil, nil, err
}
if !ok || (task.outerRowStatus[ptr.ChkIdx][ptr.RowIdx] == outerRowMatched && isSemiJoin) {
continue
}
matchedRows = append(matchedRows, outerRow)
matchedRowPtr = append(matchedRowPtr, chunk.RowPtr{ChkIdx: ptr.ChkIdx, RowIdx: ptr.RowIdx})
}
return matchedRows, matchedRowPtr, nil
}
func (iw *indexHashJoinInnerWorker) joinMatchedInnerRow2Chunk(ctx context.Context, innerRow chunk.Row, task *indexHashJoinTask,
joinResult *indexHashJoinResult, h hash.Hash64, buf []byte) (bool, *indexHashJoinResult) {
matchedOuterRows, matchedOuterRowPtr, err := iw.getMatchedOuterRows(innerRow, task, h, buf)
if err != nil {
joinResult.err = err
return false, joinResult
}
if len(matchedOuterRows) == 0 {
return true, joinResult
}
var (
ok bool
iter = chunk.NewIterator4Slice(matchedOuterRows)
cursor = 0
)
for iter.Begin(); iter.Current() != iter.End(); {
iw.outerRowStatus, err = iw.joiner.tryToMatchOuters(iter, innerRow, joinResult.chk, iw.outerRowStatus)
if err != nil {
joinResult.err = err
return false, joinResult
}
for _, status := range iw.outerRowStatus {
chkIdx, rowIdx := matchedOuterRowPtr[cursor].ChkIdx, matchedOuterRowPtr[cursor].RowIdx
if status == outerRowMatched || task.outerRowStatus[chkIdx][rowIdx] == outerRowUnmatched {
task.outerRowStatus[chkIdx][rowIdx] = status
}
cursor++
}
if joinResult.chk.IsFull() {
select {
case iw.resultCh <- joinResult:
case <-ctx.Done():
}
joinResult, ok = iw.getNewJoinResult(ctx)
if !ok {
return false, joinResult
}
}
}
return true, joinResult
}
func (iw *indexHashJoinInnerWorker) collectMatchedInnerPtrs4OuterRows(ctx context.Context, innerRow chunk.Row, innerRowPtr chunk.RowPtr,
task *indexHashJoinTask, h hash.Hash64, buf []byte) error {
_, matchedOuterRowIdx, err := iw.getMatchedOuterRows(innerRow, task, h, buf)
if err != nil {
return err
}
for _, outerRowPtr := range matchedOuterRowIdx {
chkIdx, rowIdx := outerRowPtr.ChkIdx, outerRowPtr.RowIdx
task.matchedInnerRowPtrs[chkIdx][rowIdx] = append(task.matchedInnerRowPtrs[chkIdx][rowIdx], innerRowPtr)
}
return nil
}
// doJoinInOrder follows the following steps:
// 1. collect all the matched inner row ptrs for every outer row
// 2. do the join work
// 2.1 collect all the matched inner rows using the collected ptrs for every outer row
// 2.2 call tryToMatchInners for every outer row
// 2.3 call onMissMatch when no inner rows are matched
func (iw *indexHashJoinInnerWorker) doJoinInOrder(ctx context.Context, task *indexHashJoinTask, joinResult *indexHashJoinResult, h hash.Hash64, resultCh chan *indexHashJoinResult) (err error) {
defer func() {
if err == nil && joinResult.chk != nil {
if joinResult.chk.NumRows() > 0 {
select {
case resultCh <- joinResult:
case <-ctx.Done():
return
}
} else {
joinResult.src <- joinResult.chk
}
}
close(resultCh)
}()
for i, numChunks := 0, task.innerResult.NumChunks(); i < numChunks; i++ {
for j, chk := 0, task.innerResult.GetChunk(i); j < chk.NumRows(); j++ {
row := chk.GetRow(j)
ptr := chunk.RowPtr{ChkIdx: uint32(i), RowIdx: uint32(j)}
err = iw.collectMatchedInnerPtrs4OuterRows(ctx, row, ptr, task, h, iw.joinKeyBuf)
if err != nil {
return err
}
}
}
// TODO: matchedInnerRowPtrs and matchedInnerRows can be moved to inner worker.
matchedInnerRows := make([]chunk.Row, len(task.matchedInnerRowPtrs))
var hasMatched, hasNull, ok bool
for chkIdx, innerRowPtrs4Chk := range task.matchedInnerRowPtrs {
for outerRowIdx, innerRowPtrs := range innerRowPtrs4Chk {
matchedInnerRows, hasMatched, hasNull = matchedInnerRows[:0], false, false
outerRow := task.outerResult.GetChunk(chkIdx).GetRow(outerRowIdx)
for _, ptr := range innerRowPtrs {
matchedInnerRows = append(matchedInnerRows, task.innerResult.GetRow(ptr))
}
iter := chunk.NewIterator4Slice(matchedInnerRows)
for iter.Begin(); iter.Current() != iter.End(); {
matched, isNull, err := iw.joiner.tryToMatchInners(outerRow, iter, joinResult.chk)
if err != nil {
return err
}
hasMatched, hasNull = matched || hasMatched, isNull || hasNull
if joinResult.chk.IsFull() {
select {
case resultCh <- joinResult:
case <-ctx.Done():
return ctx.Err()
}
joinResult, ok = iw.getNewJoinResult(ctx)
if !ok {
return errors.New("indexHashJoinInnerWorker.doJoinInOrder failed")
}
}
}
if !hasMatched {
iw.joiner.onMissMatch(hasNull, outerRow, joinResult.chk)
}
}
}
return nil
}