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IndexHashJoin got performance regression because of usage of sync.Pool #38695

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guo-shaoge opened this issue Oct 27, 2022 · 2 comments · Fixed by #38741
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IndexHashJoin got performance regression because of usage of sync.Pool #38695

guo-shaoge opened this issue Oct 27, 2022 · 2 comments · Fixed by #38741
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affects-6.2 affects-6.3 found/automation Found by automation tests severity/major sig/execution SIG execution type/bug The issue is confirmed as a bug. type/performance

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@guo-shaoge
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guo-shaoge commented Oct 27, 2022 •
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Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Internal process to reproduce(incall-211).

Performance of IndexHashJoin_242 got regression compared to v6.1.0. #38591 revert this #34878, IndexHashJoin_242 is normal again.

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

image

3. What did you see instead (Required)

NewIterator4Slice() takes too much cpu.

image

4. What is your TiDB version? (Required)

v6.2/v6.3
@guo-shaoge guo-shaoge added the type/bug The issue is confirmed as a bug. label Oct 27, 2022
@guo-shaoge guo-shaoge self-assigned this Oct 28, 2022
@ti-chi-bot ti-chi-bot added may-affects-4.0 This bug maybe affects 4.0.x versions. may-affects-5.0 This bug maybe affects 5.0.x versions. may-affects-5.1 This bug maybe affects 5.1.x versions. may-affects-5.2 This bug maybe affects 5.2.x versions. may-affects-5.3 This bug maybe affects 5.3.x versions. may-affects-5.4 This bug maybe affects 5.4.x versions. may-affects-6.0 may-affects-6.1 labels Oct 28, 2022
@Yui-Song Yui-Song added sig/execution SIG execution and removed may-affects-4.0 This bug maybe affects 4.0.x versions. may-affects-5.1 This bug maybe affects 5.1.x versions. may-affects-5.2 This bug maybe affects 5.2.x versions. may-affects-5.3 This bug maybe affects 5.3.x versions. may-affects-5.4 This bug maybe affects 5.4.x versions. may-affects-5.0 This bug maybe affects 5.0.x versions. may-affects-6.0 may-affects-6.1 labels Oct 28, 2022
@XuHuaiyu
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Does it mean IndexHashJoin does not invoke the pool correctly?

@guo-shaoge
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Multiple goroutines of IndexHashJoin call NewIterator4Slice concurrently for each outer row(500W), I think the there are some lock contentions in sync.Pool.Get()

@guo-shaoge guo-shaoge mentioned this issue Oct 29, 2022
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ti-chi-bot pushed a commit that referenced this issue Oct 31, 2022
@guo-shaoge
executor: fix inl_hash join performance regression because of Iterato…
7571d55 
…r4Slice (#38741)

close #38695
@ti-chi-bot ti-chi-bot mentioned this issue Oct 31, 2022
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12 tasks
@ti-chi-bot ti-chi-bot mentioned this issue Oct 31, 2022
Closed
12 tasks
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executor: fix inl_hash join performance regression because of Iterator4Slice guo-shaoge/tidb
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@guo-shaoge @XuHuaiyu @ti-chi-bot @Yui-Song