From: "Chad Wagner" <chad.wagner@xxxxxxxxx>
To: "Sidar López Cruz" <sidarlopez@xxxxxxxxxxx>
CC: pgsql-performance@xxxxxxxxxxxxxx
Subject: Re: [PERFORM] Very slow queries
Date: Tue, 30 Jan 2007 17:37:17 -0500
On 1/30/07, Sidar López Cruz <sidarlopez@xxxxxxxxxxx> wrote:
query: Delete From ceroriesgo.salarios Where numero_patrono Not In (Select
numero_patrono From ceroriesgo.patronos)
Seq Scan on salarios (cost=51021.78..298803854359.95 rows=14240077
width=6)
Filter: (NOT (subplan))
SubPlan
-> Materialize (cost=51021.78..69422.58 rows=1032980 width=25)
-> Seq Scan on patronos (cost=0.00..41917.80 rows=1032980
width=25)
How many rows exist in salarios, but not in patronos? How many rows are
there in salarios?
Rows:
Patronos: 1032980
Salarios: 28480200
What does the explain look like for:
delete
from ceroriesgo.salarios s
where not exists (select 1
from ceroriesgo.patronos
where numero_patrono = s.numero_patrono);
Also, is this not a case for a foreign key with a cascade delete?
No, this is not cascade delete case because I need to delete from salarios
not from patronos.
http://www.postgresql.org/docs/8.2/static/ddl-constraints.html
--
Chad
http://www.postgresqlforums.com/
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