Ruby on Rails - 1-2-3 to performance analysis

My cool colleagues from Trex Global gave me an unusual assignment this week: profile the current implementation of our first two apps, DeferEm and DepreciateEm.

Among the requests, the usual ones:

Request response duration
Execution profile of flow (path taken, time in methods)
SQL Queries made
Analyze and Identify performance bottlenecks - in-memory, sql query exec


After the initial despair of meeting the first time such a task, I remembered: after all, the development.log file records every controller method, action, view, SQL request as well as their execution times. So my first thought was to start digging into the log/development.log file and start grepping the heck out of it.

Wait. Don’t rush into it. There are other ways to do this.

So, after A LOT of googling, I found out about the cool and great Rails-Analyzer Rails performance analysis suite.

• Step 1: gem install production_log_analyzer and gem install rails_analyzer_tools;
  try running pl_analyze log/development.log and see some weird errors related to logging.
• Step 2: check out Geoffrey’s article over here ; download his logger replacement and add the two lines
  require 'hodel_3000_compliant_logger'
config.logger = Hodel3000CompliantLogger.new(config.log_path)
  in the config/environment.rb file ; so now you get something like

  
Rails::Initializer.run do |config|
# Settings in config/environments/* take precedence those specified here
require 'hodel_3000_compliant_logger'
config.logger = Hodel3000CompliantLogger.new(config.log_path)


• Step 3: Run again the pl_analyze command:
  pl_analyze log/development.log and enjoy the coolness of a beautiful report

Now I’m a happy man. But I still have work to do: ho do I find, for instance, the worst performing SQL requests?

We’ll see about that soon..