At RubyConf X in November 2010, Aaron Patterson (a.k.a tenderlove) gave a 45 minute talk called ZOMG WHY IS THIS CODE SO SLOW? The video of this conference, as recorded by the always awesome Confreaks, is now online. It's a must watch, if only to learn how he got commit access to both Ruby and Rails (a rare feat indeed). In the talk Aaron examines his work on Arel (as used to build up SQL queries in Rails 3.0) and how he boosted its performance, a topic he also covered in an October 2010 blog post.

The official synopsis:

In this talk, we'll take a look at different tips and tricks for writing speedy code in Ruby. We'll look at techniques for analyzing our Ruby code to find the slow spots, and ways we can speed up those hot spots. MRI's VM will be analyzed in order to understand how to take maximum advantage of our Virtual Machine. Tools for uncovering the hidden algorithms used in our legacy code will be on display! Learning to mathematically represent those algorithms will be discussed so that we can slice away at our slow code! Bring your helmets and seat belts and get ready to strap yourself in for some EXTREME programming! If you attend this talk we'll give you the whole seat, but you'll only need the edge! Space is limited, so ACT NOW!

Aaron Patterson

Just go watch it folks.