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https://issues.apache.org/jira/browse/IMPALA-9611?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tim Armstrong resolved IMPALA-9611.
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Fix Version/s: Impala 4.0
Resolution: Fixed
> Hang in HandoffToProbesAndWait() for multithreaded join build
> -------------------------------------------------------------
>
> Key: IMPALA-9611
> URL: https://issues.apache.org/jira/browse/IMPALA-9611
> Project: IMPALA
> Issue Type: Bug
> Components: Backend
> Affects Versions: Impala 3.4.0
> Reporter: Tim Armstrong
> Assignee: Tim Armstrong
> Priority: Blocker
> Labels: hang
> Fix For: Impala 4.0
>
>
> I saw a hang triggered by test_failpoints in
> JoinBuilder::HandofftoProbesAndWait(), where the thread was blocked but
> build_side_state->is_cancelled_ is true.
> The sequence of events leading to the bug is as follows:
> * Thread A is in HandoffToProbesAndWait(), reads is_cancelled_ and sees
> false.
> * Thread B in RuntimeState::Cancel() sets is_cancelled_ = true, acquires
> cancellation_cvs_lock_, then calls NotifyAll() on the condition variable
> * Thread A calls Wait() on the cv, blocks forever.
> I think this is most likely if thread A is de-scheduled at the wrong time.
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