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Memory issue due to hard referenced entities [message #1017891]

Tue, 12 March 2013 18:05

Christoph Smaul

Messages: 7
Registered: April 2012

Junior Member

Hi,

we are using eclipselink 2.4.1 (in an JEE application running on JBoss 7.1) and when we started to loadtest our application we experienced OutOfMemoryErrors after a certain while.
A closer look to the heap dump shows that, even if there are no running transactions, an increasing number of entity instances are hard referenced in a path like this:

ServerSession->orderedDescriptors->queryManager->cachedExpressionQueries->..->query->session(RepeatableWriteUnitOfWork)->cloneMapping (see attached screenshot)

There are about 900 instances of RepeatableWriteUnitOfWork, which I assume, should not be the case.

I found a quite similar issue in the bug tracker, but it is fixed since 1.1.2.

So far I could not find a way to disable caching of expression queries to test, if this is the reason for our OOMErrors.

Thanks for your responses.

Edit:
I managed to set the expression query cache to 0 for all descriptors and this really fixed our memory problem. Of course that's only a workaround, since we would like to benefit from the expression query cache.
So if anyone has a suggestion to deal with this problem in another way, please tell me.

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[Updated on: Wed, 13 March 2013 15:50]

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Re: Memory issue due to hard referenced entities [message #1018882 is a reply to message #1017891]

Thu, 14 March 2013 16:03

Chris Delahunt

Messages: 1389
Registered: July 2009

Senior Member

Can you determine how you have created and initially executed the cached ReadAllQuery? I assume this is a JPA application since it is a RepeatableWriteUnitOfWork being referenced, so it might be some JPQL query if that helps.

If so, please file a bug describing how it is occurring, and possibly try against a 2.4.2 or 2.5 build to see if code changes might have resolved the issue - though I couldn't find any issues directly related other than what you've already posted.

Best regards,
Chris

[Updated on: Thu, 14 March 2013 16:04]

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Re: Memory issue due to hard referenced entities [message #1019420 is a reply to message #1018882]

Fri, 15 March 2013 16:28

Christoph Smaul

Messages: 7
Registered: April 2012

Junior Member

Thanks for your reply.

The different ReadAllQuery instances are initialized in various code locations, most of them in stateless EJBs with an injected EntityManager using the Criteria API. Others seem to be generated when accessing lazy loaded IndirectSet members in the JAXBMarshaller. I will test again against the newer versions and file a bug as you said.

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