Rails 4.2.0 beta1 was released August 20, 2014. And according to dhh’s release post, and I quote,
a lot of common queries are now no less than twice as fast in Rails 4.2!
So, what did Rails team – or more specifically – tenderlove (Aaron Patterson) do to improve Rails/ActiveRecord so much? Let’s find out through some commits.
Here are some tools Aaron has used for measuring performance according to his Cascadia Ruby 2014 talk:
You should definitely checkout these tools. It would be very useful in your daily Ruby/Rails development.