If you are responsible for the performance of a Rails app, you will rarely get a better lesson than was provided by David Heinemeier Hansson yesterday. His company blog Signal vs. Noise carries the post where he describes his investigation into some performance issues his team was seeing in Highrise. What follows is a great example of observation, analysis and experimentation. It’s also a case study in not accepting problems at face value – David’s initial plan was to correct problems in the Notes and Contacts features code, but discovered that the root cause of the problem was a set of forms that were executing every time those features were selected.
We were pleased to see that New Relic’s RPM was one of the tools David used to diagnose and fix the problem.
Well worth reading.