About the hostname for mysql

The hostname of my system is "bob" when I echo $hostname. So I set up mysql and database.conf with that hostname. Now I read that, typically, mysql will use 'localhost' as the hostname.

Since I'm having "blank page" problems with CI 2.1.3, could I have messed things up by doing that with the hostname? On top of that, I've forgotten how I set mysql to that hostname in the first place (or did it get it from the system?).