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From Peter Lin <>
Subject Re: Tomcat performance issue?
Date Mon, 12 Apr 2004 18:07:06 GMT
>From my own experience, this kind of behavior appears when a session isn't getting timed
out for one reason or another.  For example, say you get data from some remote site using
your own Http client libraries that is multi-threaded. If that thread sits around and the
socket it has isn't explicitly closed, it can prevent tomcat from invalidating the session.
this would create a memory leak which may not be noticeable if you don't get a lot of load.
One easy way to expose this kind of bug is to load test your webapp before deploying.
Throw the load you get in 16 hrs at tomcat and you'll likely see the memory leak. In all cases,
issues with performance was due to a bug in our application. egular load testing is the best
way to expose these issues during development.

David Rees <> wrote:
Daniel Gibby wrote:
> Tomcat config:
> > className="org.apache.catalina.connector.http.HttpConnector"
> port="8080" minProcessors="5" maxProcessors="255"
> enableLookups="true" redirectPort="8443"
> acceptCount="100" debug="0" connectionTimeout="60000"/>
> Hey, I just realized something... I think I have been having lockups
> around every 16 hours... 60000 seconds! So what does that mean about
> this configuration?

connectionTimeout is defined in milliseconds, not seconds, so that is 60
seconds, not 16 hours.

> Is some servlet not returning content but hanging on to a connection?

Could be, or could be that your server is really busy. When you look at
the server-status through Apache, does it show 255 processes busy as well?

> Could you explain a little further about 'bug in a servlet causing it to
> not return'?

You could either have a deadlock (synchronization issue) in your code, or
an infinite loop.

> I have a stack trace, but I don't see how that helps me figure out where
> my problem might be... I'm not sure what exactly to look for.

Compress it and post it to the list or put it on a public webserver so we
can take a look.



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