postgres on artix has caused a few headaches.
You can indeed follow most of the archwiki guide on how to set it up, but
certain things are not to be invoked due to misleading output.

As of 15.1, this works:

doas pacman -S postgresql postgresql-libs postgresql-runit (optional: postgresql-old-upgrade)

doas ln -s /etc/runit/sv/postgresql /run/runit/service/

sudo -iu postgres

[postgres]$ initdb -D /var/lib/postgres/data

You'll see the following message, do NOT invoke the pg_ctl -D command at the
end:

```
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale "C.UTF-8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory /var/lib/postgres/data ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success. You can now start the database server using:
***DO NOT INVOKE THIS***
    pg_ctl -D /var/lib/postgres/data -l logfile start

```

You'll also need to update the /etc/runit/sv/postgresql/run file to ensure that
the /run/postgresql directory is created on start up:

if [ ! -d "/run/postgresql" ]; then
	echo "creating directory /run/postgresql"

	mkdir -p "/run/postgresql"
	chown -R postgres:postgres "/run/postgresql"
fi

Using the standard sv service manager, start up postgresql (hopefully no errors
will show, to trouble should navigate to the /etc/runit/sv/postgresql
directory and invoke doas ./run and note the output).

doas sv start postgresql

Then you should be able to start it as the postgres user using psql.

From psql, create a database/user using the interactive createuser command:

createuser --interactive

For local practice work in postgresql, name this database your name and give
them superuser privileges.

And that's it. You now from your main prompt should be able to invoke psql and
start using the database.