Paul,
> > Physical Memory: 2077264 kB
> > sort_mem = 12000
Hmmm. Someone may already have mentioned this, but that looks problematic.
You're allowing up to 12MB per sort, and up to 300 connections. Even if each
concurrent connection averages only one sort (and they can use more) that's
3600MB ... roughly 1.5 times your *total* RAM, leaving out RAM for Apache,
postmaster, shared buffers, etc.
I strongly suggest that you either decrease your total connections or your
sort_mem, or both.
--
Josh Berkus
Aglio Database Solutions
San Francisco