Hi Ayhan,
I applied the patch that is derived from the one suggested by Phil
(his patch and comments finally made the cause of the leak obvious to
me. Doh!):
https://issues.apache.org/cayenne/browse/CAY-770
I'd appreciate if you could build the code from SVN and confirm that
the fix worked. Then I'll close the issue. Let me know if you need
help with the build.
Thanks
Andrus
On Feb 21, 2007, at 10:55 AM, Ayhan Kondoz wrote:
> Hi,
>
>
>
> i think i found a possible bug / memory leak within the
> DispatchQueue and EventManager.
>
>
>
>
>
> First a little bit about my setup:
>
>
>
> I have 3 servers. Each server runs an axis service. The service
> uses cayenne 1.2.1 to connect to a database. It reads customer and
> account information from the DB etc..
>
> The servers are using cayenne's shared caching with javagroups as
> the messaging service so that changes made from one server are
> dispatched to the other servers.
>
>
>
> The avarage connections per second is somewhere around 4-5.
>
>
>
> However I have a very strange problem with this setup so I startet
> to search for the reason. The problem is that with nearly constant
> and unchanging usage the load of each server increases over time.
> To further test this I created a test server with a similar setup.
> There I created a test program that creates totally constant usage.
> But even with the unchanging usage the load of the server is
> increasing until the cpu load is so high that the requests can not
> be processed anymore.
>
>
>
> I installed a java profiler to trying to pinpoint the location of
> this error and this is what I found out.
>
>
>
> I let the server run for 24 hours and then stopped the program
> which creates the test usage.
>
> But even while the server was idle there where still a lot of
> instances in the java heap after the GC run.
>
>
>
> http://img206.imageshack.us/img206/9769/memorysy5.jpg
>
>
>
> Please note the HashMap, WeakReference and Invocation counts. I
> pressume that the $ObjectProvider_*** is cayenne aswell but I am
> not sure.
>
>
>
> Now the following image shows the cpu profile with incoming
> connections.
>
>
>
> http://img339.imageshack.us/img339/2441/cpuci0.jpg
>
>
>
> As you can see 58% of the cpu time is used within HashSet.add().
>
>
>
> So when I consider the two facts i think that there might be a
> possible problem with the EventManager. The first table tells us
> that there are over 1 million instances of HashSet's and cayenne
> Invocations. So it seems like the set's within the DispatchQueue
> are not recycled properly so that the object count rises over time
> which result in extremly high processtime when trying to add new
> HashSet's.
>
>
>
>
>
> Thanks
>
> Ayhan
>
>
>
>
>
>
>
> Ayhan Kondoz
>
>
>
> Software-Entwicklung
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