Re: A couple of patches for PostgreSQL 64bit support

=?ISO-8859-1?Q?Hans-J=FCrgen_Sch=F6nig?= <postgres@cybertec.at> writes:
> There is some practical evidence. Recently the number of large boxes in
> the field is almost growing exponentially. Today I have heard somebody
> say "this box has 'just 4 gig of ram' ".
> On large installations we have already seen problems with too small
> caches (= 2gb).
> Surprisingly this has turned out to be a quite important issue in the
> field. Tests have shown that the cache provided by the OS is a lot worse
> for the database.

*What* tests?  This is all handwaving :-(

What I would find credible is a set of, say, OSDL test runs, showing a
continuing increase of performance with shared_buffers right up to the
2Gb limit.  Everything done to date says that you hit the point of
diminishing returns well before that.

            regards, tom lane