Faster loading times with Ruby 1.9.3 and Rails 3.2

There are lots of performance improvements which got pushed with the release of Ruby 1.9.3 and Rails 3.2. I am writing about 2 major changes which has improved the Rails bootup time by upto 36% and faster development mode.

Problem with Ruby 1.9.2
When you look at the codebase of Rails, it is pretty huge and it has lot of ‘require’ statements hanging around. So what is the problem? We all know that, ruby’s require statement by itself is quite interesting. How? When you do a require in ruby, ruby will actually require the content only if it is not required before. Which means if your require something which was already required, ruby skips it. Let me show you an example.

When there were talks on how to improve the rails load time, they found that the problem was with Ruby core itself. The way ruby manages the required file information was quite aweful. Thanks to Xavier for his patch, which did the magic.

#ruby 1.9.2 way of requiring the files
def require(file)
  $loaded.each do |x|
    return false if x == file

#ruby 1.9.3 way of requiring the files
def require(file)
  return false if $loaded[file]
  $loaded[file] = true

The above code represents the rubyish way what actually Xavier’s patch is actually doing. It was that hash look-up which entirely changed the way ruby handled the require(s) and improved the performance by upto 36%. I did a benchmark by myself, both with 1.9.2 and 1.9.3, and I found it to be pretty fast. Checkout my screenshots below. Awesome! So upgrade to 1.9.3 and get a 36% faster rails bootup time.

Faster development mode in Rails 3.2
Atlast I am happy that it was not just me who got pissed of with slower developement mode in Rails. ActiveReload is the new candidate in Rails 3.2 which fastens your development mode. How? Well Rails is little stupid, it just forgets the code it executed after it processed the request. For the next request Rails again loads your code entirely. I hope you know this is how you have been skipping your server restart in dev. Now the big deal is imagine if you have changed only 1 out of 10 models, Rails is going to load all the 10 models again for the next request. ActiveReload does something interesting, it tells rails to reload only the files which has changed. So only the changed file gets loaded again. Thats cool!! Checkout Rails 3.2 release notes for further information. Happy coding.

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