Re: Starting PostgreSQL 8.0.4 with more memory [FreeBSD 6.0]

Vlad <marchenko(at)gmail(dot)com> writes:
> I'm looking for some help in regards to letting Posresql use more
> memory.

8.0 can't go past 2Gb of shared memory, and there is really no reason
to try because its performance will get worse not better with more than
about 50000 shared buffers.

8.1 will relax the 2Gb limit, but it's still far from clear that there's
any point in it. The conventional wisdom is that you should leave most
of memory free for kernel disk cache, not try to eat it all in shared
buffers. I haven't seen any evidence that that's changed in 8.1. It
might possibly make sense to use several Gb of shared buffers in a
machine with 16Gb or more of RAM, but not in one with only 4Gb RAM.

BTW, where did you get the idea that it was sensible to set work_mem
higher than maintenance_work_mem? That's just nuts.

See the pgsql-performance archives for past discussions of this topic.

regards, tom lane