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From Christopher Giblin <...@zurich.ibm.com>
Subject Re: influence connection usage?
Date Wed, 30 Sep 2009 10:59:57 GMT
Hi Mike,
Thank you very, very much. That was exactly what I needed. Works perfectly.
The OpenJPA documentation is excellent but substantial - I missed that.
Thanks, chris


> 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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