The MySQL Query Log in OS X Leopard

I installed MySQL 5.1 Community Server on my MacBook Pro using the convenient installer provided by the folks at MySQL. Something you should be aware of when doing this is that it will not install a configuration file anywhere. You'll be running with defaults unless you create a (or copy one of the provided) my.cnf file in one of the appropriate locations.

Default options may be fine for most local workstation installations. However, I wanted to see the query log. The easiest way to enable the query log is to add an entry to your my.cnf file under [mysqld] that looks something like this.

log=/var/log/mysqld.log

I initially chose /var/log becuase that's where OS X keeps some of its other log files and I thought it would be nice to keep log files together in the same place. I restarted the MySQL server and ran a couple of queries but the log file never showed up. It turns out there's a problem with the permissions on the /var/log directory. It's owned by root:wheel and is only writable by the owner. The mysql user is not in the wheel group and thus cannot create files in this directory.

Given that OS X maintains this directory I know any changes I make to it might get reverted at any point in the future. So I chose to simply create my logs in another location. An easy candidate is /usr/local/mysql/data but you can use any directory choose if you don't want to mix data and logs.