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https://issues.apache.org/jira/browse/CASSANDRA-14194?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16386485#comment-16386485
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Ariel Weisberg commented on CASSANDRA-14194:
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RE #1 I think this is a correct fix. Totally makes sense that clobbering the
more work indicator after already starting to collect the next batch of work is
going to cause this issue.
RE #2 This won't happen because LockSupport.unpark() will cause it to wake
immediately I believe?
https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/locks/LockSupport.html#unpark(java.lang.Thread)
RE #3 looks good.
RE #4 should be fine. It's only read when doing hideously expensive operations
that dwarf the cost of a volatile read anyways.
+1
> Chain commit log marker potential performance regression in batch commit mode
> -----------------------------------------------------------------------------
>
> Key: CASSANDRA-14194
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14194
> Project: Cassandra
> Issue Type: Bug
> Components: Core, Testing
> Reporter: Ariel Weisberg
> Assignee: Jason Brown
> Priority: Major
> Fix For: 3.0.x, 3.11.x, 4.x
>
> Attachments: jstack.txt
>
>
> CASSANDRA-13987 modified how the commit log sync thread works. I noticed that
> cql3.ViewTest and ViewBuilderTaskTest have been timing out, but only in
> CircleCI. When I jstack in CircleCI what I see is that the commit log writer
> thread is parked and the threads trying to append to the commit log are
> blocked waiting on it.
> I tested the commit before 13987 and it passed in CircleCI and then I tested
> with 13987 and it timed out. I suspect this may be a general performance
> regression and not just a CircleCI issue.
> And this is with write barriers disabled (sync thread doesn't actually sync)
> so it wasn't blocked in the filesystem.
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