Articles about Performance

Notes from The Complete Guide to Rails Performance's Workshop

If you are interested in Ruby and Rails performance, you have definitely read articles by Nate Berkopec from Speedshop. At Ombu Labs we are big fans of his work, his Complete Guide to Rails Performance book and Slack community.

When Nate announced a series of public workshops I didn't hesitate and signed up as quickly as possible. Here are my notes from my experience at the workshop on October 17th.

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Present? vs Any? vs Exists?

When working on a Rails project, you may have seen present? calls on ActiveRecord relationships. This might feel natural, mostly because present? exists on all objects via ActiveSupport, so you expect the relationship to respond to it, but it's actually not a very good idea. If all we want to do is check if the scope returns any results from the database, there are better ways than using present?.

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Hunting Down a Slow Rails Request

Recently, we started using Skylight in production for one of our clients' Rails applications, in an attempt to try to improve the performance of some of the more critical API endpoints.

Skylight reports on:

  • Time taken per request
  • Breakdown of time taken per SQL query
  • Object allocations per request

I noticed an unusually large amount of allocated objects for one request:

Skylight report

This request would take anywhere from 400ms to 3000ms to respond, which is WAY too long.

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