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

Off hanbd I can't recommend anything, bur perhaps you could post the details of the tables (columns, indexes),and some
infoon 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

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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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