RPM Status

At NewRelic we eat our own dogfood.  We monitor the RPM site continuously to identify performance and availability problems when they occur in our server.  But as we all know, performance problems aren’t limited to the server.  Using tools like Firebug and YSlow you can identify inefficiencies in the browser rendering pages and unnecessarily fetching static assets.

Recently we identified just such a problem on rpm.newrelic.com.  We had occasional reports of sluggishness in the site and it became apparent that Firefox was not always pulling assets from its local cache but instead returning to the server for a fresh copy for every page.  It was a transient problem, hard to reproduce, and seemed to go away as quickly as it appeared.  A little more investigation revealed the problem having to do with the way Firefox caches assets for SSL sites, like ours.  For security, it caches everything in memory and priority is given to assets returned with a CacheControl of public.  We were not adding that CacheControl option so some users would experience slowdown after having their browser up for a while and visiting many SSL sites.

We don’t know how many users ran into this transient slowdown.  We only had a couple of reports about it.  But yesterday we did update our server to add the extra cache header (along with the far future expires time which was already there) so Firefox users should no longer run into this problem.

We’d love to hear from you if you notice any difference one way or another.  Let us know with an e-mail to support@newrelic.com.