From: Mario Weilguni <mweilguni@sime.com>
To: pginfo <pginfo@t1.unisoftbg.com>
Cc: pgsql-general@postgresql.org
Subject: Re: query optimization
Date: Tue, 15 Oct 2002 10:12:13 +0200
Message-ID: <200210151012.13724.mweilguni@sime.com> (raw)
In-Reply-To: <3DABBE6F.67930574@t1.unisoftbg.com>
References: <3DABBE6F.67930574@t1.unisoftbg.com>
> Sort (cost=37.44..37.44 rows=1 width=1118) (actual
> time=12140.96..12141.02 rows=48 loops=1)
> -> Nested Loop (cost=0.00..37.43 rows=1 width=1118) (actual
> time=115.02..12138.57 rows=48 loops=1)
> -> Nested Loop (cost=0.00..33.42 rows=1 width=886) (actual
> time=0.58..20.77 rows=48 loops=1)
> -> Index Scan using i_sklad_ids_doc on a_sklad n
> (cost=0.00..28.58 rows=1 width=760) (actual time=0.36..8.59 rows=48
> loops=1)
> -> Index Scan using a_location_pkey on a_location sk
> (cost=0.00..4.82 rows=1 width=126) (actual time=0.09..0.12 rows=1
> loops=48)
> -> Seq Scan on a_nomen nom (cost=0.00..3.45 rows=45 width=232)
> (actual time=0.03..165.45 rows=6702 loops=48)
> Total runtime: 12142.07 msec
It seems the query planner is completly wrong here, look on the line
Seq Scan on a_nomen nom (cost=0.00..3.45 rows=45 width=232) (actual time=0.03..165.45 rows=6702 loops=48)
This means the planner expects 45 return rows (guessed from statistics), but actually gets 6702 rows.
Do "VACUUM ANALYZE a_nomen" and try your query again.
If it fails:
Do you have a unique index on a_nomen(ids)?
Regards,
Mario Weilguni
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To: pgsql-general@postgresql.org
Cc: mweilguni@sime.com, pginfo@t1.unisoftbg.com
Subject: Re: query optimization
In-Reply-To: <200210151012.13724.mweilguni@sime.com>
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