Tim Perdue <tim@perdue.net> writes:
> Our database is about 1GB in total size, the machine has 4GB, but the entire
> system is only using 1.2 GB, even during vacuum or a daily, extremely large
> query that requires a lot of grouping and sorting.
What have you got the SortMem parameter (backend -S switch) set to?
That's about the only use I can think of for RAM beyond what's needed to
cache the whole database ...
regards, tom lane