| From: | Hannu Krosing <hannu(at)tm(dot)ee> |
|---|---|
| To: | Dennis Haney <davh(at)diku(dot)dk> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Another optimizer question |
| Date: | 2004-01-27 21:22:14 |
| Message-ID: | 1075238534.2554.22.camel@fuji.krosing.net |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Dennis Haney kirjutas T, 27.01.2004 kell 21:08:
> Tom Lane wrote:
> > Dennis Haney <davh(at)diku(dot)dk> writes:
> >
> > > There is no constraint on the order of 'a', so why is pull_up_subqueries
> > > explicitly ignoring subqueries that contain an 'order by'?
> > >
> > Because there would be no place to apply the sort operation.
> Then why spend time doing it at all?
> > If you are saying you don't want the sort to occur,
> >
> I'm saying the sort makes no sense. So why even bother executing it?
>
> > why did you write it?
> I believe the most common scenario would be that the subquery was
> expanded from a view...
And why is it written on the outer level of view. AFAIK any select from
that view is also free to ignore it.
-----------
Hannu
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Manfred Spraul | 2004-01-27 21:33:40 | Re: Mixing threaded and non-threaded |
| Previous Message | Dennis Bjorklund | 2004-01-27 21:16:52 | Re: Function call |