Retire old database connections just like Rails v8.1

Rails v8.1 introduced some new options for managing database connections, particularly a few that are useful when running against a pooler, e.g. PgBouncer, namely:

• max_age: number of seconds the pool will allow the connection to exist before retiring it at next checkin. (default Float::INFINITY).
• pool_jitter: maximum reduction factor to apply to max_age interval (default 0.2; range 0.0-1.0).

An existing (but not well-documented) parameter that is also useful in this scenario is reaping_frequency, which determines how often the reaper thread checks for connections to retire (it defaults to 60 seconds).

However, there's a problem here: this is only supported as of Rails v8.1. Maybe your site isn't running the latest and greatest yet. Maybe... gasp maybe you're still on Ruby v2.5! What is a poor developer to do? Stop whining and update, obviously. While you're working on that, you can use this gem.

Add this line to your application's Gemfile:

gem 'activerecord_connection_reaper'

Then install it:

$ bundle install

Once you do that, you can use the max_age, pool_jitter, and reaping_frequency options in your database configuration almost as if you were actually on Rails v8.1. Note that this gem is purposefully not compatible with Rails v8.1, to make sure you remember to remove it when you ARE finally able to update.