Re: zero performance on query

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От Bruno Wolff III
Тема Re: zero performance on query
Дата
Msg-id 20051026175930.GC11447@wolff.to
обсуждение исходный текст
Ответ на Re: zero performance on query  ("Jim C. Nasby" <jnasby@pervasive.com>)
Список pgsql-admin
On Tue, Oct 25, 2005 at 22:36:58 -0500,
  "Jim C. Nasby" <jnasby@pervasive.com> wrote:
> We need the output of EXPLAIN ANALYZE, from both versions if possible.

Isn't that going to be a problem in this case since it seems unlikely
that EXPLAIN ANALYZE will finish in a reasonable amount of time?

>
> Also, pgsql-performance would be a better list for this...
>
> On Tue, Oct 25, 2005 at 05:31:22PM -0600, Sidar L?pez Cruz wrote:
> > what happend with postgresql 8.1b4 performance on query?
> >
> > look at this:
> > select count(*) from fotos where archivo not in (select archivo from
> > archivos)
> > Aggregate  (cost=4899037992.36..4899037992.37 rows=1 width=0)
> >  ->  Seq Scan on fotos  (cost=22598.78..4899037338.07 rows=261716 width=0)
> >        Filter: (NOT (subplan))
> >        SubPlan
> >          ->  Materialize  (cost=22598.78..39304.22 rows=805344 width=58)
> >                ->  Seq Scan on archivos  (cost=0.00..13141.44 rows=805344
> > width=58)
> >
> > I WILL DIE WAITING FOR QUERY RESPONSE !!!
> > --
> > CREATE TABLE archivos ( archivo varchar(20)) WITHOUT OIDS;
> > CREATE INDEX archivos_archivo_idx  ON archivos  USING btree(archivo);
> > ~800000 rows
> > --
> > CREATE TABLE fotos
> > (
> >  cedula varchar(20),
> >  nombre varchar(100),
> >  apellido1 varchar(100),
> >  apellido2 varchar(100),
> >  archivo varchar(20)
> > ) WITHOUT OIDS;
> > CREATE INDEX fotos_archivo_idx  ON fotos  USING btree (archivo);
> > CREATE INDEX fotos_cedula_idx   ON fotos   USING btree (cedula);
> > ~500000 rows
> >
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> --
> Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
> Pervasive Software      http://pervasive.com    work: 512-231-6117
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