Re: different behaviour between select and delete when constraint_exclusion = partition

[Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>]

Marc Cousin <cousinmarc(at)gmail(dot)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