Re: Multiple Buffer pools

Nailah Ogeer <ogeer(at)cs(dot)queensu(dot)ca> writes:
> I am currently undergoing the project of making postgres's single buffer
> pool into multiple buffer pools hopefully to decrease the number of
> physical reads. Just wondering if anyone has done some work on this
> before.

To be honest, I think this is a complete waste of effort, as the optimal
buffering scheme for Postgres relies on OS-level caching more than
PG-internal caching. But yes, it's been discussed before. See the
archives for pgsql-performance and pgsql-hackers.

> Also, I need some information on where the number of relations in
> the system is defined.

There is no very practical way to determine that. Any one backend can
only see one database, not the entire cluster; and at the time shared
memory is sized, you don't have any database access capability at all.

regards, tom lane