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eclipselink flush mode out of memory [message #1007742]

Thu, 07 February 2013 11:31

Andrew Petrov

Messages: 2
Registered: February 2013

Junior Member

In my project I use eclipselink JPA
In properties xml to encrease perfomance a make
eclipselink.persistence-context.flush-mode = COMMIT
As I see all inserts are made when transaction commit.
So when I give more test data I'l get out of memory exception.

<properties>
<property name="eclipselink.jdbc.batch-writing" value="Oracle-JDBC" />
<property name="eclipselink.jdbc.cache-statements" value="true" />
<property name="eclipselink.jdbc.native-sql" value="true" />
<property name="eclipselink.cache.size.default" value="5000" />
<property name="eclipselink.persistence-context.flush-mode" value="COMMIT" />
</properties>

Is there any option to say to JTA to flush when cache for insert too big. Or maybe I can make smth like : flush each 1000 rows. But will be cache limiting in Mb for example.

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Re: eclipselink flush mode out of memory [message #1007760 is a reply to message #1007742]

Thu, 07 February 2013 12:35

Chris Delahunt

Messages: 1240
Registered: July 2009

Senior Member

You cam control when statements are flushed using EntityManager.flush(), and clear the cache using em.clear(). Using the two at appropriate intervals to allow statements to be batched will help performance and reduce memory use, but you will need to tune it appropriately.

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Re: eclipselink flush mode out of memory [message #1007766 is a reply to message #1007760]

Thu, 07 February 2013 12:55

Andrew Petrov

Messages: 2
Registered: February 2013

Junior Member

Yes this ofcourse come to my mind. First I just give more memory to java machine, but that was not enough and I understand that I should tune it manually but hope that some configuration properties exists.
Because this property flush-mode seems like an legal memory leak. You just turn it on and there is a huge possibility to get out of memory.

Thanks for you answer, maybe there are any property that we don't know. Smth like to say : make commit every 100 sentencies

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Re: eclipselink flush mode out of memory [message #1007772 is a reply to message #1007766]

Thu, 07 February 2013 13:20

Chris Delahunt

Messages: 1240
Registered: July 2009

Senior Member

Flush mode will not drastically change the memory footprint. Statements are only generated on the flush and should be quickly garbage collected if needed, while the entity cache will still fill up unless it is cleared.

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