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From Rainer Jung <rainer.j...@kippdata.de>
Subject Re: java.lang.OutOfMemoryError: Java heap space
Date Tue, 06 Oct 2009 13:25:00 GMT
On 05.10.2009 18:58, Joe Hansen wrote:
> Thank you so much for your tips, Rainer!
> 
> The websites went down yet again. Increasing the java heap size took
> care of the OutOfMemoryError, but the number of httpd processes keep
> increasing until the websites crash. I haven't added any new code in
> the past few months, hence I am surprised why the requests are getting
> stuck. Here's a link to the tomcat thread dumps:
> http://pastebin.com/m17eea139
> 
> Please let me know if you cannot view it and I will email the relevant
> portion of the catalina.out file to you. Is there an easy way to find
> out what code is causing the requests to get stuck?

The dump file contains three thread dumps.

The things all dumps have in common:

- 60 threads for the quartz scheduler, all idle
- 13 threads in the AJP connection pool, connected to Apache, but idle
waiting for the next request to be send (the same threads in all three
dumps)
- 6 store plus 6 expiry threads of the EHCache, seems idle
- 1 AJP + 1 HTTP(S) thread (port 8443) waiting to accept the next new
connection to come in
- 2 AJP + 3 HTTP(S) threads (port 8443) sitting idle the pool, waiting
for work
- a couple of other normal threads not directly related to request handling

So the time you took the three dumps, this Tomcat was completely idle
and did not have a single request to handle.

If you are completely sure, you took the dumps while there was a storm
of requests and your system couldn't cope the load, something has
prevented the requests to ever reach Tomcat.

I don't have your Tomcat version at hand at the moment, but for some
time very special OutOfMemory errors (could not create native thread)
lead to a situation, where Tomcat simply wouldn't accept any new
connections. Although you report OutOfMemory errors, I'm not directly
suggesting that that is your problem here. There might still be a
relation though.

Are you sure, that you took the dumps for the right Tomcat at the right
time?

Regards,

Rainer

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