wshwsh12
commented
1 month ago Code Analyze
- Context canceled. getNewJoinResult return joinResult without chk and error.
joinMatchedInnerRow2Chunk if joinResult.chk.IsFull() { select { case iw.resultCh <- joinResult: // <- send to resultCh the first time. case <-ctx.Done(): } failpoint.InjectCall("joinMatchedInnerRow2Chunk") joinResult, ok = iw.getNewJoinResult(ctx) if !ok { return false, joinResult } }
func (iw indexHashJoinInnerWorker) getNewJoinResult(ctx context.Context) (indexHashJoinResult, bool) { joinResult := &indexHashJoinResult{ src: iw.joinChkResourceCh, } ok := true select { // <- random select a path case joinResult.chk, ok = <-iw.joinChkResourceCh: case <-ctx.Done(): // <- choose this path return joinResult, false } return joinResult, ok }
2. doJoinUnordered return nil error.
``` go
ok, joinResult = iw.joinMatchedInnerRow2Chunk(ctx, row, task, joinResult, h, iw.joinKeyBuf)
if !ok {
return joinResult.err // nil
}- indexHashJoinInnerWorker try to handle the next task and exit. doJoinUnordered doesn't return joinResult, so indexHashJoinInnerWorker always hold the first joinResult with the same chunk.
select { //<-random select a path case <-ctx.Done(): return case task, ok = <-iw.taskCh: // <- choose this path } if !ok { break // exit this loop }
...... ...... if resultCh == iw.resultCh { if joinResult.err != nil { resultCh <- joinResult return } if joinResult.chk != nil && joinResult.chk.NumRows() > 0 { select { // <- random select a path case resultCh <- joinResult: // <- choose this path, send to resultCh the second time. case <-ctx.Done(): return } } }
4. Next() try to get the two joinResult and give back chk to joinChkResourceCh(cap 1), and hang forever.
XuHuaiyu
seiya-annie
Bug Report
Please answer these questions before submitting your issue. Thanks!
1. Minimal reproduce step (Required)
Context canceled may occur at any time if the sql is interrupted during execution.
I try to inject context cancel to indexhashjoin, to reproduce the issue. Patch this diff to index_lookup_join.go
Run the UT
2. What did you expect to see? (Required)
Can run successfully.
3. What did you see instead (Required)
Hang forever. goroutine in master.
goroutine in v6.5.6
4. What is your TiDB version? (Required)
master, v6.5.6