Re: Optimization of this SQL sentence - Mailing list pgsql-performance

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If just just realized that is a litlle faster (15% faster) with this:

CREATE INDEX idx_statustype
   ON "comment" USING btree (idstatus, ctype);

Any other ideas?


Gregory S. Williamson escribió:
> Off hanbd I can't recommend anything, bur perhaps you could post the details of the tables (columns, indexes),and
someinfo on what version of postgres you are using. 
>
> Are the tables recently analyzed ? How many rows in them ?
>
> Greg Williamson
> DBA
> GlobeXplorer LLC
>
>
> -----Original Message-----
> From:    pgsql-performance-owner@postgresql.org on behalf of Ruben Rubio
> Sent:    Tue 10/17/2006 2:05 AM
> To:    pgsql-performance@postgresql.org
> Cc:
> Subject:    [PERFORM] Optimization of this SQL sentence
>
> This SQL sentence is very simple. I need to get better results. I have
> tried some posibilities and I didn't get good results.
>
> SELECT max(idcomment)
>  FROM ficha vf
>  INNER JOIN comment c ON (vf.idficha=c.idfile AND (idestado=3 OR
> idestado=4))
>  WHERE idstatus=3
>  AND ctype=1
>
>
> QUERY PLAN
>
> Aggregate  (cost=2730.75..2730.76 rows=1 width=4) (actual
> time=188.463..188.469 rows=1 loops=1)
>
>   ->  Hash Join  (cost=1403.44..2730.72 rows=11 width=4) (actual
> time=141.464..185.404 rows=513 loops=1)
>
>         Hash Cond: ("outer".idfile = "inner".idficha)
>
>         ->  Seq Scan on "comment" c  (cost=0.00..1321.75 rows=1083
> width=8) (actual time=0.291..36.112 rows=642 loops=1)
>
>               Filter: ((idstatus = 3) AND (ctype = 1))
>
>         ->  Hash  (cost=1403.00..1403.00 rows=178 width=4) (actual
> time=141.004..141.004 rows=6282 loops=1)
>
>               ->  Seq Scan on ficha vf  (cost=0.00..1403.00 rows=178
> width=4) (actual time=0.071..97.885 rows=6282 loops=1)
>
>                     Filter: (((idestado)::text = '3'::text) OR
> ((idestado)::text = '4'::text))
>
> Total runtime: 188.809 ms
>
>
> Thanks in advance,
> Ruben Rubio

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