panic: send on closed channel

[ChenPeng2013]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

panic: send on closed channel [recovered]
        panic: send on closed channel

goroutine 766775274 [running]:
github.com/pingcap/tidb/executor.(*IndexMergeReaderExecutor).handleHandlesFetcherPanic.func1(0x38f2ac0, 0x420f910)
        /home/jenkins/agent/workspace/optimization-build-tidb-linux-amd/go/src/github.com/pingcap/tidb/executor/index_merge_reader.go:619 +0x205
github.com/pingcap/tidb/util.WithRecovery.func1(0xc2faf42f30)
        /home/jenkins/agent/workspace/optimization-build-tidb-linux-amd/go/src/github.com/pingcap/tidb/util/misc.go:92 +0x354
panic(0x38f2ac0, 0x420f910)
        /usr/local/go/src/runtime/panic.go:965 +0x1b9
github.com/pingcap/tidb/executor.(*partialTableWorker).syncErr(...)
        /home/jenkins/agent/workspace/optimization-build-tidb-linux-amd/go/src/github.com/pingcap/tidb/executor/index_merge_reader.go:432
github.com/pingcap/tidb/executor.(*partialTableWorker).fetchHandles(0xc02cdabdd0, 0x429f548, 0xc2ec561ec0, 0xc17c86c720, 0xc13bf13320, 0xc13bf13200, 0xc17c86c5a0, 0x42cd6f8, 0xc2eb6c8d20, 0xa, ...)
        /home/jenkins/agent/workspace/optimization-build-tidb-linux-amd/go/src/github.com/pingcap/tidb/executor/index_merge_reader.go:448 +0x678
github.com/pingcap/tidb/executor.(*IndexMergeReaderExecutor).startPartialTableWorker.func1.1()
        /home/jenkins/agent/workspace/optimization-build-tidb-linux-amd/go/src/github.com/pingcap/tidb/executor/index_merge_reader.go:374 +0x5ba
github.com/pingcap/tidb/util.WithRecovery(0xc3295def08, 0xc2faf42f30)
        /home/jenkins/agent/workspace/optimization-build-tidb-linux-amd/go/src/github.com/pingcap/tidb/util/misc.go:100 +0x4f
github.com/pingcap/tidb/executor.(*IndexMergeReaderExecutor).startPartialTableWorker.func1(0x429f5f0, 0xc2f818d950, 0xc1e8ad8900, 0xc0ff91f0e0, 0x0, 0xc2f480d540, 0x1, 0x1, 0xc17c86c720, 0xc13bf13320)
        /home/jenkins/agent/workspace/optimization-build-tidb-linux-amd/go/src/github.com/pingcap/tidb/executor/index_merge_reader.go:326 +0x1e5
created by github.com/pingcap/tidb/executor.(*IndexMergeReaderExecutor).startPartialTableWorker
        /home/jenkins/agent/workspace/optimization-build-tidb-linux-amd/go/src/github.com/pingcap/tidb/executor/index_merge_reader.go:323 +0x238

2. What did you expect to see? (Required)

3. What did you see instead (Required)

4. What is your TiDB version? (Required)

Release Version: v5.3.0
Edition: Community
Git Commit Hash: bdc9987370d6d393cb8acae22e238e3350e448b5
Git Branch: heads/refs/tags/v5.3.0
UTC Build Time: 2021-11-03 13:20:53
GoVersion: go1.16.4
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false

[ChenPeng2013]

the default of tidb_enable_index_merge is off, so the severity is set to major

[fuzhe1989]

/assign @guo-shaoge

[guo-shaoge]

Is this a failed ci log? Can we reproduce this error? @ChenPeng2013

[guo-shaoge]

Why we got the error: the partialIndexWorker got an error and it tries to give this error to the main worker through resultCh. But the resultCh is already closed(maybe Close() is called already).

Because there is too little log information, it is hard to get a more accurate conclusion. IMO, it's not a big problem.

[ChenPeng2013]

Is this a failed ci log? Can we reproduce this error? @ChenPeng2013

I found it by tidb_error.log and don't have a way to reproduce

[guo-shaoge]

Is this a failed ci log? Can we reproduce this error? @ChenPeng2013

I found it by tidb_error.log and don't have a way to reproduce

I will update the pr and verify the fix.

[zanmato1984]

Adjusting severity to minor.

[guo-shaoge]

#41036
this refactor pr can fix this.