Re: FK index q'n

Tom Lane wrote:
> rihad <rihad(at)mail(dot)ru> writes:
> > Given this table:
> > CREATE TABLE foo (
> > id integer primary key,
> > bar_id integer references bar (id)
> > );
> > and provided that bar.id is itself a PK, do I still need to create an
> > index on bar_id if often doing queries like:
> > SELECT MIN(id) FROM foo WHERE bar_id IS NULL;
>
> Now as far as the above-illustrated query goes, no simple index is going
> to help it, because IS NULL is not an indexable operation.

Unless you are on 8.3, that is.

--
Alvaro Herrera http://www.amazon.com/gp/registry/CTMLCN8V17R4
Y dijo Dios: "Que sea Satanás, para que la gente no me culpe de todo a mí."
"Y que hayan abogados, para que la gente no culpe de todo a Satanás"