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https://issues.apache.org/jira/browse/SOLR-2342?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12990554#comment-12990554
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Michael McCandless commented on SOLR-2342:
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Fixing the client threads to not commit in the end, so no client is committing,
and then turning on Solr's auto-commit, still hits the starvation.
> Lock starvation can cause commit to never run when many clients are adding
> docs
> -------------------------------------------------------------------------------
>
> Key: SOLR-2342
> URL: https://issues.apache.org/jira/browse/SOLR-2342
> Project: Solr
> Issue Type: Bug
> Components: update
> Reporter: Michael McCandless
> Priority: Minor
>
> I have a stress test, where 100 clients add 100 1MB docs and then call commit
> in the end. It's a falldown test (try to make Solr fall down) and nowhere
> near "actual" usage.
> But, after some initial commits that succeed, I'm seeing later commits always
> time out (client side timeout @ 10 minutes). Watching Solr's logging, no
> commit ever runs.
> Looking at the stack traces in the threads, this is not deadlock: the
> add/update calls are running, and new segments are being flushed to the index.
> Digging in the code a bit, we use ReentrantReadWriteLock, with add/update
> acquiring the readLock and commit acquiring the writeLock. But, according to
> the jdocs, the writeLock isn't given any priority over the readLock (unless
> you set fairness, which we don't). So I think this explains the starvation?
> However, this is not a real world use case (most apps would/should call
> commit less often, and from on client). Also, we could set fairness, but it
> seems to have some performance penalty, and I'm not sure we should penalize
> the "normal" case for this unusual one. EG see here (thanks Mark):
> http://www.javaspecialists.eu/archive/Issue165.html.
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