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From Michael Dick <>
Subject Re: influence connection usage?
Date Tue, 29 Sep 2009 15:12:18 GMT
Hi Christopher,
Take a look at the openjpa.ConnectionRetainMode property [1] [2].


It sounds like you'd benefit from setting it to 'always' or 'transaction'.


On Tue, Sep 29, 2009 at 8:08 AM, Christopher Giblin <>wrote:

> Hi,
> Is there any way to influence OpenJPA's connection usage when not using
> connection pooling?
> I plan to move to connection pooling in the future but cannot quite at the
> moment. My OpenJPA is configured to use Derby ClientDataSource. When
> iterating over objects with lazy-loaded attributes, the query is naturally
> issued to fill the proxy as each object is accessed. However,  I never get
> through the whole array because eventually the OS has too many TCP
> connections (> 2000)  closing (in state TIME_WAIT) and can no load open any
> more connections.  It seems each access opens and closes an DB connection
> and hence a TCP connection. I get partially around this by changing queries
> and using eager loading. But I cannot do this in all cases.
> I am wondering, is it possible to get OpenJPA to reuse a connection, rather
> than opening and closing so frequently?
> Thanks,chris

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