Re: Strange query plan

On Tue, 5 Jun 2001, Tom Lane wrote:

> Oleg Bartunov <oleg@sai.msu.su> writes:
> > should be
> > select msg_prt.tid as mid from msg_prt
> >  where exists (select idx.tid from idx where msg_prt.tid=idx.tid
> >                and idx.did=1 and ( idx.lid = 1207 or idx.lid=59587 ));
> > but this is not a big win.
>
> Shouldn't be any win at all: the IN expression-list notation will get
> translated to exactly that form.

Sure

>
> > Anyway, what's about original query ?
>
> IN/EXISTS subqueries suck.  This has been true for a long time and is
> going to be true for a while longer, unless someone else fixes it before
> I have a chance to look at it.  See if you can't rewrite your query as
> a plain join.
>

That's why we've moved to GiST and feel fine :-) That query we used in
our old project, now swithing to GiST.


>             regards, tom lane
>
Regards,    Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83