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From Michael Dick <michael.d.d...@gmail.com>
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].

[1]
http://openjpa.apache.org/builds/latest/docs/manual/manual.html#openjpa.ConnectionRetainMode
[2]
http://openjpa.apache.org/builds/latest/docs/manual/manual.html#ref_guide_dbsetup_retain

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

Regards
-mike

On Tue, Sep 29, 2009 at 8:08 AM, Christopher Giblin <CGI@zurich.ibm.com>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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