Tomcat CPU spikes in Jruby web app


We have a Jruby on rails application deployed in tomcat. Our Jruby
version is 1.5.1 and tomcat version is 6.0.26. However with a simple app
also the app server CPU is showing 100% utilization for a considerable
amount of time.

We also eliminated db queries , just to eliminate the db layer as a
susppect, however still there was considerable CPU utilization on the
app server. Our database is PostgreSQL version 1.8.4

Anyone has any ideas what could be happenning?

There’s actually a bug similar to this that should be fixed in JRuby
1.5.5 and the upcoming 1.6. Can you try to update and see if the
problem improves?

On Thu, Nov 18, 2010 at 11:14 PM, Prachi T.


Thanks for ur prompt reply.

Jruby 1.6 is still in dev right? When will it be released for production
use? Our app has been deployed in production. So this is a production
issue. So what do u recommend, upgrading to 1.5.5?

Yes, I would recommend upgrading to 1.5.6. If you are using OpenSSL,
make sure you’re on the latest jruby-openssl gem as well.

Some of the issues you mention have been fixed on the 1.5 branch, and
are in 1.5.6. As for JRuby 1.6, we hope to have at least RCs out this
month and a final version soon after. If you have cycles to test a
development build of 1.6, you can go to
to get one.

  • Charlie

On Fri, Nov 19, 2010 at 1:02 AM, Prachi T.