RailsRequestStats provides a simple drop-in solution to expose more statistics on requests. New information is presented in your development logs, supplying you with the required information to iteratively optimize requests by noticing subtle changes in the number of queries and average runtimes.
ActiveJob in Rails provides nice benefits. The background queueing gem Sidekiq allows for tailored options that you cannot use with ActiveJob. This post looks at a project's transition from ActiveJob to Sidekiq, and how to fill the missing functionality of ActiveJob Callbacks. By the end, we come up with a way to contain the callback logic to their own modules without modifying the concrete jobs.
When you are knee deep in Ruby and dealing with objects that you never created it's sometimes a little daunting to trace everything back and figure it all out. Luckly there are a couple techniques in Ruby that can aid you. In particular, pry is an extreamly powerful tool that you should have in your toolbox.
Do you define methods within your Rake tasks? You might want to reconsider that, or you're gonna have a bad time down the road. Walkthrough an example which illustrates a tricky gotcha and solutions to avoiding it.