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Posted to ojb-user@db.apache.org by Vasily Ivanov <ba...@gmail.com> on 2007/11/16 09:26:13 UTC
getIteratorByQuery + thousands of objects = OutOfMemoryError
Hello,
We've got a system that needs to update thousands (possibly hundreds
of thousands) of Objects.
After reading OJB FAQ I thought that
PersistenceBroker.getIteratorByQuery(query) would be the best solution
in this case. Query runs fine and returns RsIterator. However the
problems start when I try to iterate and process few thousands of
records eventually I get OutOfMemoryError (out of java heap). I did
profiling and found that QueryReferenceBroker object holds a big
ArrayList called prefetchingListeners that grows rapidly while
iterating. I think that's because OJB keeps all objects to commit when
PersistenceBroker is closed.
What I do is I call the following statement after each iteration:
((PersistenceBrokerInternal)
pb).getReferenceBroker().removePrefetchingListeners();
That helped but that's obviously not the best way of doing it and I
don't know how thread-safe it is.
Is there any more appropriate way of doing that?
Thank you,
Vasily
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Re: getIteratorByQuery + thousands of objects = OutOfMemoryError
Posted by Vasily Ivanov <ba...@gmail.com>.
We are using Ojb 1.0.4.
On 16/11/2007, Vasily Ivanov <ba...@gmail.com> wrote:
> Hello,
>
> We've got a system that needs to update thousands (possibly hundreds
> of thousands) of Objects.
>
> After reading OJB FAQ I thought that
> PersistenceBroker.getIteratorByQuery(query) would be the best solution
> in this case. Query runs fine and returns RsIterator. However the
> problems start when I try to iterate and process few thousands of
> records eventually I get OutOfMemoryError (out of java heap). I did
> profiling and found that QueryReferenceBroker object holds a big
> ArrayList called prefetchingListeners that grows rapidly while
> iterating. I think that's because OJB keeps all objects to commit when
> PersistenceBroker is closed.
>
> What I do is I call the following statement after each iteration:
> ((PersistenceBrokerInternal)
> pb).getReferenceBroker().removePrefetchingListeners();
>
> That helped but that's obviously not the best way of doing it and I
> don't know how thread-safe it is.
>
> Is there any more appropriate way of doing that?
>
> Thank you,
> Vasily
>
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