Matthew,
> I read through the entire archive at
> http://archives.postgresql.org/pgsql-performance/ and didn't see much talk
> on the subject. It only goes back 8 months though, so I don't know if there
> is another archive that is more comprehensive...
Really? There was a long-running Mac OS X vs. Solaris thread that touched on
most major platforms, about 2-3 months ago.
> I don't suspect that individual tables will be 2GB, but that the size of all
> tables combined will be. If there is a limitation on the largest chunk of
> RAM allocated to a program, will I have problems?
No. Since PostgreSQL is a multi-process architecture, not a multi-threaded,
you only need enough RAM per process to load the current largest query.
Plus, in my experience, Disk I/O issues are vastly more important than RAM in
database performance. You're better off spending money on really fast disks
in Linux RAID or really good hardware RAID 1+0 ....
--
-Josh Berkus
Aglio Database Solutions
San Francisco