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https://issues.apache.org/jira/browse/LUCENE-3803?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13211622#comment-13211622
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Uwe Schindler commented on LUCENE-3803:
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The problem is that you are using the same fixed thread pool for everything. If
you only have 1 or 2 threads in the pool (as noted in your mail) and one of
those threads calls searcher.search() from within its own callable,
searcher.search will try to execute the sub-searches in its own callables. If
the thread pool does not have enough free threads, it will wait for a thread to
get available (because another callable finishes). The callable that called
searcher.search will of course not finish as it waits for itsself to finish ->
deadlock.
The bad idea with thread pools that leads to your problem is: Don't start
Callables from within another Callable in the same thread pool. This almost
always leads to deadlocks.
> Using a searcher with an executor service does not work from within a
> Callable called by that same executor service
> -------------------------------------------------------------------------------------------------------------------
>
> Key: LUCENE-3803
> URL: https://issues.apache.org/jira/browse/LUCENE-3803
> Project: Lucene - Java
> Issue Type: Bug
> Components: core/search
> Affects Versions: 3.5
> Reporter: Benson Margulies
> Attachments: lucene-tc.tgz
>
>
> The test case I'm about to attach creates an executor service uses invokeAll
> to run things from it. The 'things' (Callable) that it runs in turn run
> Lucene searchers using a searcher that has the very same executor service.
> This turns out to hit some sort of deadlock related to the executor service
> queue.
> I won't be terribly surprised if this is really a matter of a fundamental
> limitation of the executor service, but if nothing else this JIRA might
> provoke a warning in the javadoc. Or, what do I know, maybe there's a way
> Lucene could interact with the executor service that gets along with this?
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