Re: different behaviour between select and delete when constraint_exclusion = partition - Mailing list pgsql-general

From Tom Lane
Subject Re: different behaviour between select and delete when constraint_exclusion = partition
Date
Msg-id 16690.1269959668@sss.pgh.pa.us
Whole thread Raw
In response to different behaviour between select and delete when constraint_exclusion = partition  (Marc Cousin <cousinmarc@gmail.com>)
List pgsql-general
Marc Cousin <cousinmarc@gmail.com> writes:
> Anyway here is the problem : when using constraint_exclusion=partition, a
> delete query scans all partitions, when the same query rewritten as a select
> is removing partitions as expected. When constraint_exclusion=on, the
> partition removal works as expected with the delete too. I've tested it on 8.4
> and 9.0

Hmm, this seems like a shortcoming in the constraint_exclusion=partition
feature.  The reason it doesn't work is that inheritance expansion of a
DELETE/UPDATE target rel is handled entirely differently from expansion
of a SELECT source. But it seems like it would be desirable if it did
work.

            regards, tom lane

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