# High CPU load upon upgrade to 2.3.5 **URL:** \ **Category:** Rails\ **Created:** [March 1, 2010, 6:02pm UTC](https://www.ruby-forum.com/t/high-cpu-load-upon-upgrade-to-2-3-5/184371 "2010-03-01T18:02:45Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![twaters](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/a6a055/32.png) [@twaters](https://www.ruby-forum.com/u/twaters)\ **Post date:** [March 1, 2010, 6:02pm UTC](https://www.ruby-forum.com/t/high-cpu-load-upon-upgrade-to-2-3-5/184371/1 "2010-03-01T18:02:45Z")
After recently updating a rather large app from 2.0.2 to 2.3.5 (running on ruby 1.8.6, latest apache and passenger) the CPU used by the ruby process would jump to 100% for a good 3 secs and locked up the server within minutes. I was able to roll back the changes easily enough, but I am now pulling out my hair trying to figure what the issue might be. How can I figure out what it is in my large code base that has run perfectly smoothly on 2.0.2 for years, but now running on 2.3.5 causes the CPU to jump to 100% and render the app unusable? (The app runs fine and all my tests pass, it just crumbles under any load) Thanks… ---
**Author:** ![twaters](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/a6a055/32.png) [@twaters](https://www.ruby-forum.com/u/twaters)\ **Post date:** [March 3, 2010, 11:01pm UTC](https://www.ruby-forum.com/t/high-cpu-load-upon-upgrade-to-2-3-5/184371/2 "2010-03-03T23:01:54Z")
Tim W wrote: > ``` > After recently updating a rather large app from 2.0.2 to > 2.3.5 > (running on ruby 1.8.6, latest apache and passenger) the CPU used by > the ruby process would jump to 100% for a good 3 secs and locked up > the server within minutes. I was able to roll back the changes easily > enough, but I am now pulling out my hair trying to figure what the > issue might be. > > How can I figure out what it is in my large code base that has run > perfectly smoothly on 2.0.2 for years, but now running on 2.3.5 causes > the CPU to jump to 100% and render the app unusable? (The app runs > fine and all my tests pass, it just crumbles under any load) > > Thanks… > ``` Anything in the logs.  Does it work the same way in production as in development.  Have you tried it with another server (like mongrel or webrick) to see if there is any interaction with passenger....  I am a brute force debugger...I would just add some logger calls in the likely places to see what is going on... do any of the gems you use need to be updated for 2.3.5 and did any of them change?? Norm – You received this message because you are subscribed to the Google Groups “Ruby on Rails: Talk” group. To post to this group, send email to removed\_email\_address@domain.invalid. To unsubscribe from this group, send email to removed\_email\_address@domain.invalid. For more options, visit this group at [http://groups.google.com/group/rubyonrails-talk?hl=en.](http://groups.google.com/group/rubyonrails-talk?hl=en.) ---
**Author:** ![twaters](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/a6a055/32.png) [@twaters](https://www.ruby-forum.com/u/twaters)\ **Post date:** [March 4, 2010, 8:36am UTC](https://www.ruby-forum.com/t/high-cpu-load-upon-upgrade-to-2-3-5/184371/3 "2010-03-04T08:36:05Z")
Having been through similar questions I’d say… Use passenger-status (called frequently) to check the global wait queue. Use newrelic to drill down to slowest actions (and from there where the time is spent). Analyse the logs for slow requests (and what parameters were sent in/where the time was spent). I have a repo of some potentially useful utilities at - > **[GitHub - andyjeffries/rails-analysis-tools: Tools for analysing Rails and...](https://github.com/andyjeffries/rails-analysis-tools)** > > Tools for analysing Rails and Apache logs for performance - GitHub - andyjeffries/rails-analysis-tools: Tools for analysing Rails and Apache logs for performance rails\_log\_analyser might be useful (it summarises requests from a passenger log and then enables you to output just the log for that request which can be difficult when different request lines overlap). passenger\_mon\_grapher may also be useful (in reference to my first point) but you’ll need to write your own sampler to parse the output of passenger-status and write it to a CSV file every few seconds. Cheers, Andy – Andy J. [http://andyjeffries.co.uk/](http://andyjeffries.co.uk/)#rubyonrails #mysql #jquery Registered address: 64 Sish Lane, Stevenage, Herts, SG1 3LS Company number: 5452840 ---
**Author:** ![twaters](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/a6a055/32.png) [@twaters](https://www.ruby-forum.com/u/twaters)\ **Post date:** [March 4, 2010, 10:39am UTC](https://www.ruby-forum.com/t/high-cpu-load-upon-upgrade-to-2-3-5/184371/4 "2010-03-04T10:39:01Z")
On Mar 1, 5:01 pm, Tim W [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > fine and all my tests pass, it just crumbles under any load) > There was a change between 2.3.3 and 2.3.4 where escape\_once (used > among other things by form helpers) became quite a bit more expensive, > in order to fix a security bug. If your app is ok on 2.3.3 but not on > 2.3.4 then that’s probably the root cause Fred