Greetings,
However, I still see where the database at times can run VERY hot.
We have set up this server to run with PostgreSQL. When I do a ps aux | grep postgres, I find a lot of processes that have been spawned to take care of mailman - a dozen or so.
Out of the box Pg performs pretty well but still benefits from tuning.
Recommend you head over to
https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server and see
what makes sense for your configuration.
Anectodally, at my work we produce an app with Pg as the backend
database. Simple tuning, including turning synchronous_commit off,
yielded us 10x better performance. Granted, our app is very write-heavy
and typically Mailman and friends will be far more read-heavy, so giving
Pg enough RAM for in-memory sorts and caching will benefit you more.
--cro