Setting up a database is a relatively straightforward process (Heroku has an add-on for that), but getting it to run well in production is sometimes another matter. As your application grows and your data grows along with it, you will likely find a number of performance bottlenecks specifically related to your database, and this post aims to help you diagnose and address those issues when they arise.

As with all components of your infrastructure it’s important to have early visibility into the performance characteristics of your database. Watching this data as your application grows will give you a much better chance of spotting performance issues and regressions as they’re introduced.

I...

This blog post is adapted from a talk given by Amy Unger at RailsConf 2018 titled "Knobs, buttons & switches: Operating your application at scale."

We've all seen applications that keel over when a single, upstream service goes down. Despite our best intentions, sometimes an unexpected outage has us scrambling to make repairs. In this blog post, we'll take a look at some tools you can integrate into your application before disaster strikes. We'll talk about seven strategies that can help you shed load, fail gracefully, and protect struggling services. We'll also talk about the technical implementations of these techniques—particularly in Ruby, though the...

Debugging is an important skill to develop as you work your way up to more complex projects. Seasoned engineers have a sixth sense for squashing bugs and have built up an impressive collection of tools that help them diagnose and fix bugs.

I'm a member of Heroku’s Ruby team and creator of CodeTriage and today we’ll look at the tools that I used on a journey to fix a gnarly bug in Sprockets. Sprockets is an asset packaging system written in Ruby that lies at the heart of Rails’ asset processing pipeline.

At the end of the post, you will know how Sprockets works and how to debug in Ruby.

Unexpected Behavior in Sprockets

Sprockets gives developers a convenient way to compile, minify,...

This blog post is adapted from a talk given by Stella Cotton at RailsConf 2018 titled "So You’ve Got Yourself a Kafka."

Rails applications that use ActiveRecord objects in their cache may experience an issue where the entries cannot be invalidated if all of these conditions are true:

1. They are using Rails 5.2+
2. They have configured config.active_record.cache_versioning = true
3. They are using a cache that is not maintained by Rails, such as dalli_store (2.7.8 or prior)

In this post, we discuss the background to a change in the way that cache keys work with Rails, why this change introduced an API incompatibility with 3rd party cache stores, and finally how you can find out if your app is at risk and how to fix it.

Even if you're not at Rails 5.2 yet, you'll likely get there one day. It's...