Using a Postgres Version Manager

It works on my machine! I would place a confident bet every developer has said this (likely more than once!).

Chances are, you are brew updating postgres on your machine far more than your team is doing so for production. Chances are, every time there is a new postgres version brew updates for you, you have came across the nightmare of something going astray. Going down the whirlwind of fun of reading what feels like a monolith of stackoverflows and random medium articles to help you solve. Copy and pasting commands blindly out of desperation. Finally bringing yourself to completely uninstall and reinstall postgres. Yet, the mystery is still unresolved. A pid file somewhere still hanging out…more blind copy and pasting commands that look like hieroglyphics at this point. brew stop postgres && brew start postgres just can not get it together. Soul crushing...

What if you always used the postgres version that matched your production environment? What if you could have multiple postgres versions as needed for your various applications? What if you could switch versions using a tool you might already use to switch ruby versions, node versions etc?

The solution is here: asdf. As explained in the README, "asdf is a CLI tool that can manage multiple language runtime versions on a per-project basis."

Backstory:

Being a long time rvm’er for managing different ruby versions. I was not immediately ready to make the switch. I had yet to find anything note worthy for a node version manager. I decided to only use asdf for nodejs to test it out. Finally, a node version manager tool that was not trash! It worked and it worked well. Took the next big step: rvm implode. What a breath of fresh air! It is worth mentioning .default-gems is nothing short of beautiful when installing a new ruby version.

I realized there was an array of asdf plugins I had never thought to version manage that I should actually manage! Given ruby/rails are my go to loves, postgres is essentially the standard for any rails application. Therefore, it ranks high on my list of things I should have down solid on my machine.

** This assumes you already have asdf installed. See asdf install instructions to install via method of choice. **

asdf

So it begins…

$ brew uninstall postgis
$ brew uninstall postgres

# This takes some time to install compared to brew
$ asdf install postgres latest

# set as default postgres version
$ echo 'postgres 13.0' >>~/.tool-versions

# install different postgres version
$ asdf install postgres 12.4

# set `postgres 12.4` in .tool-versions of repository
$ echo 'postgres 12.4' >>~/your_repo/.tool-versions

Takeaways

• Slight change in behavior compared to brew. With brew, postgres was always running and it always "just worked". Truthfully, I never thought about postgres running. I would start a local server or open postico and everything always worked. Now, I am far more aware of things as I must explicitly start and stop postgres because I now specify which version is needed. This was similar when switching to using asdf for ruby. Before, I was inconsistent about running bundle exec before commands. With rvm, I would run into "it worked on my machine"…due to not realizing my machine had multiple versions of a gem installed and the latest one was being used. With asdf, if there is more than one version of anything, you are forced to bundle exec. This was a great habit to get into and also made me more aware of exactly what packages were being used. The difference with postgres, is there is not really an error. It is more like trying to use postico and not being able to connect because well...that version is not running. Same thing for applications, try to enter a rails console, I need to make sure to start postgres and stop postgres when I need to switch.
• The main takeaway is to remember to stop the server first when switching! For example, although asdf current said using verison 13, 12.4 was still running. When running bundle exec rails db:create, the database was created under version 12.4 and not 13. I had to stop 12.4, then start 13, then create, then all is good. It would be nice if asdf had a better way to handle this.

The commands are:

pg_ctl start
pg_ctl stop

Query for Postgres Version:

select version()

Troubleshooting:

PG::ConnectionBad: could not connect to server: No such file or directory
  Is the server running locally and accepting
  connections on Unix domain socket "/var/pgsql_socket/.s.PGSQL.5432"?

• Try echo 'export PGHOST=localhost' >>~/.bash_profile
• I only had this issue on one machine. Not sure why I did not need to do this on the second machine.

Respect

• To Jay Dorsey for introducing me to asdf.
• To markdown-to-medium. I was surprised Medium does not support markdown! Kudos to Open Source for solving!