Re: Query runs too long for indexed tables

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От Marc Morin
Тема Re: Query runs too long for indexed tables
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Msg-id 2BCEB9A37A4D354AA276774EE13FB8C2BCC556@mailserver.sandvine.com
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Ответ на Query runs too long for indexed tables  ("Andrus" <eetasoft@online.ee>)
Список pgsql-performance
Explain analyze would be nice ;-)

> -----Original Message-----
> From: pgsql-performance-owner@postgresql.org
> [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Andrus
> Sent: Tuesday, April 04, 2006 3:37 PM
> To: pgsql-performance@postgresql.org
> Subject: [PERFORM] Query runs too long for indexed tables
>
> I have relatively small tables (toode and rid) in fast server.
> Both tables are indexed on toode field.
>
> Following query takes long time to run.
> toode field type is char(20). It is difficult to change this
> field type.
>
> Any idea how to speed up this query ?
>
> UPDATE firma1.rid SET toode=NULL
>        WHERE toode IS NOT NULL AND
>        toode NOT IN (SELECT TOODE      FROM firma1.TOODE);
>
> Query returned successfully: 0 rows affected, 594813 ms
> execution time.
>
> explain window shows:
>
> Seq Scan on rid  (cost=2581.07..20862553.77 rows=51848 width=1207)
>   Filter: ((toode IS NOT NULL) AND (NOT (subplan)))
>   SubPlan
>     ->  Materialize  (cost=2581.07..2944.41 rows=14734 width=84)
>           ->  Seq Scan on toode  (cost=0.00..2350.34
> rows=14734 width=84)
>
>
> Andrus.
>
>
>
> ---------------------------(end of
> broadcast)---------------------------
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>

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