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From David Kerber <>
Subject Re: Problem with connection pool
Date Sat, 30 Apr 2011 13:09:17 GMT
On 4/30/2011 6:58 AM, chris derham wrote:
> All,
>> What do you mean by "swapped out"?
> Idle speculation in the face of a problem that I didn't really understand
> :-(
>>> 69% of all threads are sleeping on a monitor.
>> Fully expected, since that's what they do when waiting for work to show up.
>>> This might indicate they are waiting for some external
>>> resource (e.g. database) which is overloaded or not
>>> available
>> You don't need to speculate;
> I wasn't speculating - both lines were a quote from thread dump analyzer.
>> Using removeAbandoned and logAbandoned might be of interest.
>> ...
>> More evidence of a broken app, not returning connections to the pool when
>> it's done with them.
> Our code uses hibernate. We never touch connections directly. We ask
> hibernate to execute some SQL, and it handles all the get/return connection.
> Hence I was some what sceptical of this advice. However having followed this
> user group for a few months now, I get that you know what you are talking
> about. So I turned on the logging, and sure enough at one point during
> initialization, we obtained a connection and didn't return it. So thanks for
> pointing out that setting.
> Finally managed to track the problem down to nested transactions -
> apparently spring doesn't support them. Once removed the problem went away
> Thanks for all your help
> Chris

Glad you got it sorted out, and thanks for telling us what the problem 
was; it may save somebody else from the same headaches in the future.


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