Re: PostgreSQL and memory usage

Dann Corbit wrote:

> I have a machine with 4 CPU's and 2 gigabytes of physical ram.
>
> I would like to get PostgreSQL to use as much memory as possible. I
> can't seem to get PostgreSQL to use more than 100 megabytes or so.
>
> How can I optimize the use of PostgreSQL to get the maximum throughput
> in a configuration like that?
>
> Are there any memory usage/tuning documents I can read?
>

I'm not sure if there is a document, but there are some things you can do.

First, size the shared memory pool. I've been told by Tom that too much
is actually slower, but making it MUCH bigger than the default does help
a lot.

shared_buffer=2048
(Maybe larger, experiment)

Sort memory, this is useful for large queries that do sorting, it is
allocated as needed on a per process basis. If you run large queries
that sort, this can speed you up instead of sorting to disk.

sort_mem=16384

OK, lastly, do not dispare if PostgreSQL seems not to be using as much
memory as is in your system. Don't forget the OS disk cache is important
too.