Switch The Running Postgres Server Version

I use asdf install and manage multiple versions of Postgres on my Mac OSX machine. With asdf and project-based .tools-versions files, I can control what version of Postgres (psql) I use at a project-level.

The one snag with this workflow is managing the currently running server version. Lets say I need to switch from a project using 12.3 to a project using 13.1. If the Postgres server running on my machine is using the Postgres server 12.3, then I'll need to manually stop that server and start up the Postgres server 13.1.

This can be done like so:

# stop the 12.3 server
$ $HOME/.asdf/installs/postgres/12.3/bin/pg_ctl \
    -D $HOME/.asdf/installs/postgres/12.3/data \
    stop

# start the 13.1 server
$ $HOME/.asdf/installs/postgres/13.1/bin/pg_ctl \
    -D $HOME/.asdf/installs/postgres/13.1/data \
    start

This uses the specific asdf-versioned pg_ctl command to stop and start the servers.

I've found it tedious to dig up these commands each time I need to switch, so I added a switch_pg function to my ~/.zshrc config.