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Re: Same condition in the CTE and in the subsequent JOIN using it - Mailing list pgsql-general

From Andreas Kretschmer
Subject Re: Same condition in the CTE and in the subsequent JOIN using it
Date
Msg-id ac694010-61fb-55c0-926d-f663e183e9d2@a-kretschmer.de
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In response to Same condition in the CTE and in the subsequent JOIN using it  (Alexander Farber <alexander.farber@gmail.com>)
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Am 25.04.2018 um 17:45 schrieb Alexander Farber:
> Thank you for any hints, I apologize if my question is too specific 
> and difficult to answer...

i haven't checked the whole query, but where-conditions from the outer 
query are not pushed down into the CTE-query. First the whole CTE will 
be materialized, then the outer query executed.
that said, it is better to define the where-condition in the cte.

https://blog.2ndquadrant.com/postgresql-ctes-are-optimization-fences/

Regards, Andreas

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2ndQuadrant - The PostgreSQL Support Company.
www.2ndQuadrant.com

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