Re: Very slow queries

On 1/30/07, Sidar López Cruz <sidarlopez(at)hotmail(dot)com> 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?

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?

http://www.postgresql.org/docs/8.2/static/ddl-constraints.html

--
Chad
http://www.postgresqlforums.com/