Re: [c3p0-users] c3p0 connection leak in a multi threaded environment

[Dobes V. <do...@gm...>]

I could be wrong, but I believe there is some kind of system where when a
connection is released it goes into a queue for a while before it is
re-used.  This might be impacted by some of the c3p0 settings.

If the connections are being re-used quickly then the thread that picks up
the "closed" connections and makes them available again might fall behind.

Hope that helps ...

Cheers,

Dobes


On Mon, Jan 24, 2011 at 8:22 AM, yaog <yai...@gm...> wrote:

>
> I've got a bug from one of our teams where they claim they see too many
> Oracle connections being opened compared to the number of threads that are
> requesting connections.
>
> I've built a simple application that demonstrates this  and very quickly I
> indeed see things like:
>
> 2011/01/24 18:16:14.180 [MultiThreadConnPoolingTest] [pool-1-thread-1]:
> INFO
> : live : 32. busy: 5. idle:  27
> 2011/01/24 18:16:14.180 [MultiThreadConnPoolingTest] [pool-1-thread-3]:
> INFO
> : live : 32. busy: 5. idle:  27
> 2011/01/24 18:16:14.181 [MultiThreadConnPoolingTest] [pool-1-thread-5]:
> INFO
> : live : 32. busy: 5. idle:  27
> 2011/01/24 18:16:14.183 [MultiThreadConnPoolingTest] [pool-1-thread-2]:
> INFO
> : live : 32. busy: 5. idle:  27
> 2011/01/24 18:16:14.183 [MultiThreadConnPoolingTest] [pool-1-thread-4]:
> INFO
> : live : 32. busy: 5. idle:  27
>
>
> You can see how the number of connections in the pool is very high and a
> high value of idle connections as well. Why would so many connections be
> opened for only 5 threads?
>
> Indeed only 5 are busy...
>
> We have concluded this is because of the very very a sync nature of
> resource
> handling in c3p0. However - it still looks like a bug that truly idle
> connections are not identified correctly.
>
> We made sure that all connection are being closed properly.
>
> Any Ideas why this is happening?
>
> Regards,
>
> Yair
> --
> View this message in context:
> http://old.nabble.com/c3p0-connection-leak-in-a-multi-threaded-environment-tp30748064p30748064.html
> Sent from the c3p0 - users mailing list archive at Nabble.com.
>
>
>
> ------------------------------------------------------------------------------
> Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)!
> Finally, a world-class log management solution at an even better
> price-free!
> Download using promo code Free_Logger_4_Dev2Dev. Offer expires
> February 28th, so secure your free ArcSight Logger TODAY!
> http://p.sf.net/sfu/arcsight-sfd2d
> _______________________________________________
> c3p0-users mailing list
> c3p...@li...
> https://lists.sourceforge.net/lists/listinfo/c3p0-users
>