# Benchmarking various methods of accumulating a set / unique array in ruby

John Bachir's Code Blog
July 24, 2022

I recently benchmarked a few ways to accumulate a set in ruby. Here are my findings and methodology - apologies for messiness, I'm just sharing what I came up.

This is with ruby 3.1. I also ran under 2.7, I believe the set case was actually faster, but I may be misremembering.

## Results

### Time

 user system total . . .

# You can't declare after_*_commit or after_commit callbacks for the same method more than once!

### wow.

John Bachir's Code Blog
February 25, 2022

In Rails ActiveRecord, I just discovered that if you do this:

# bad code!
after_update_commit :thing
after_create_commit :thing


Only the second one will take effect! After asking in the rails slack, I was pointed to the docs which actually cover this:

Using both after_create_commit and after_update_commit . . .

# Instrumenting and Scaling the Action Cable worker pool

John Bachir's Code Blog
January 06, 2022

Action Cable (aka ActionCable or action_cable) is a mature, useful stack of tech that allows easily integrating two-way communication in a Rails app via websockets.

There seems to be a complete lack of discussion on the web about instrumenting or scaling it. Here are my findings and experiments to that end so far.

The one . . .

# How to install homebrew in a completely isolated environment

John Bachir's Code Blog
November 10, 2021

I'm a longtime macports fan and occasional evangelist. It Just Works, installs in /opt/local with sudo, and very frequently installs binaries instead of needing to build. Homebrew is widely used and supported and pretty great, but I always feel just a little better about using macports instead and haven't had a reason to switch.

. . .

# Turning off ActiveRecord query cache to improve memory consumption in background jobs

John Bachir's Code Blog
October 17, 2021

The ActiveRecord query cache can defeat effective garbage collection when working on big batches of data. Disabling it entirely in background jobs can be a solid memory consumption win. Here's how to do it:

## Sidekiq

app/lib/sidekiq_ar_cache.rb

class SidekiqArCache
def call(worker, msg, queue)
ActiveRecord:: . . .

# How to stop yourself from accidentally switching to a git branch named "master" instead of "main"

### or vice-versa

John Bachir's Code Blog
October 02, 2021

If you have various projects which used either "main" or "master" as the main branch, and also have a remote which uses the other naming (e.g. heroku or another PaaS), you might find yourself accidentally switching to the wrong branch name and working on it. Here's how to inhibit that.

Put this in . . .

# ruby Thread report_on_exception and abort_on_exception

John Bachir's Code Blog
September 25, 2021

ruby Thread has two interesting settings related to behavior when an error happens: report_on_exception and abort_on_exception.

There are a few good articles out there about this, but a couple things gets overlooked a bit:

1. behavior which depends on if a thread is joined or not
2. the interaction of the two settings . . .