I spent the weekend migrating from my shared hosting at Dreamhost over to VPS hosting at SilverRack. In the move, I setup my housing app to run on postgresql instead of mysql. I was in for a few surprises though.
When I ran db:migrate, I got a strange error:
rake aborted! No such file or directory - /tmp/.s.PGSQL.5432
At first I thought it was because postgres wasn't started, but that didn't make sense because I had another terminal with psql running just fine. If you follow the --trace message, you'll find that the most poorly named option in database.yml will fix this problem:
production: adapter: postgresql # ... other stuff host: /var/run/postgresql
The 'host' parameter is the directory Rails looks in to get the tmp file to determine how to connect to postgres. I guess in other *nix systems this is conventionally in tmp, but that's not true for Debian based distros.
After fixing that, I ran into another little problem:
psql: FATAL: Ident authentication failed for user "xxx"
This one comes as a result of good defaults by the Debian postgresql configs. A quick google solved this one:
# add to pg_hba.conf, found in /etc/postgresql/... local all all trust host all 127.0.0.1 255.255.255.255 trust
For a cheatsheet of setting up a Rails project with Postgresql, check out this guide I wrote a while back.