Re: [SQL] query with subquery abnormally slow?

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От Tom Lane
Тема Re: [SQL] query with subquery abnormally slow?
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Msg-id 2748.941494228@sss.pgh.pa.us
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Ответ на query with subquery abnormally slow?  (Oskar Liljeblad <osk@hem.passagen.se>)
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Oskar Liljeblad <osk@hem.passagen.se> writes:
> I'm doing a SELECT query with a subquery on a table with 12K rows
> but it is very slow (10 seconds+). The query looks like this:

>   select *
>     from items
>     where package in
>       (select package
>          from items
>          where ...blah...
>          group by package)

Have you considered something like

select i1.* from items i1, items i2 where
i1.package = i2.package and i2.performer ~ '...';

This would only be fast given an index on package, I think,
but you said you had one...
        regards, tom lane


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