On Wed, Sep 07, 2005 at 12:22:27PM -0400, Christian Compagnon wrote:
> I'm a newbie in postgresql, I've installed it on a Windows XP machine
> ( I can't use linux, it's a company machine ), I'm courious why this
> query takes so long
It sounds like you've set work_mem too low; increasing it might help. Also
try rewriting your query to
SELECT "Rut Cliente"
FROM "Internet_Abril"
WHERE
"Rut Cliente" NOT IN ( SELECT "Rut Cliente" FROM "Internet_Enero" )
AND "Rut Cliente" NOT IN ( SELECT "Rut Cliente" FROM "Internet_Febrero" )
AND "Rut Cliente" NOT IN ( SELECT "Rut Cliente" FROM "Internet_Marzo" )
(I'm not sure how optimized UNION inside an IN/NOT IN is.)
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