Before (Rails 3.0.1pre stable branch + Arel 1.0.1): [] After (Rails 3.1.0 master branch + Arel 2.0.0dev master branch: [] Thanks to the awesome work done by Aaron Patterson (@tenderlove) and others. :-) UPDATE: After Aaron Patteron’s tweet, I ran the tests again on Rails 3.0.1pre stable branch + Arel 2.0.0dev master branch, and the result blew my mind: []