Re: Query take 101 minutes, help, please

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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