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https://issues.apache.org/jira/browse/METRON-728?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15880824#comment-15880824
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ASF GitHub Bot commented on METRON-728:
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Github user justinleet commented on the issue:
https://github.com/apache/incubator-metron/pull/463
@cestella The more I'm thinking about this, the more I wonder if this test
is inherently structured incorrectly. My thinking is that it seems more like
we're testing whether or not a stream can run in parallel, rather than that the
stream produced by the spliterator meets the appropriate contracts for a stream.
Is there a way to restructure this so that it just tests "Does this meet
the criteria of a Java stream?", rather than "Can a stream in Java run in
parallel?"
> ReaderSpliteratorTest fails randomly and extremely rarely
> ---------------------------------------------------------
>
> Key: METRON-728
> URL: https://issues.apache.org/jira/browse/METRON-728
> Project: Metron
> Issue Type: Bug
> Affects Versions: 0.3.1
> Reporter: Justin Leet
> Assignee: Justin Leet
>
> See logs at
> https://travis-ci.org/justinleet/incubator-metron/builds/203298348
> I was able to reproduce this locally by calling
> {{testActuallyParallel_mediumBatch}} in a {{while(true)}} loop. It can also
> occur in {{testActuallyParallel_mediumBatchImplicitlyParallel()}}. I also
> had to add
> {{forkJoinPool.shutdownNow();}} to the end of the test, because otherwise OOM
> errors occur.
> My current assumption is that there's no guarantee you ever actually end up
> running in parallel, so in extremely rare cases you just end up running one
> thread.
> I've had it vary wildly when I hit it, from within a second or two to running
> for over a minute before an assertion failure occurs.
> We could just alter the assertion to be
> {code}Assert.assertTrue(threads.size() <= (int) Math.ceil(9.0 / 2) &&
> threads.size() >= 1);{code}
> This defeats the purpose of testing the parallelism a bit, but if there's no
> guarantee we actually get parallelism there's not a fantastic way to test it.
> Given the extreme rarity, we might want to just live with the fact that
> occasionally {{threads.size() >= 1}} hits the threads.size() == 1 case on the
> two tests.
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