Re: Incorrect explain output for updates/delete operations with returning-list on partitioned tables

SAIKIRAN AVULA <avulasaikiranreddy(at)gmail(dot)com> writes:
> I have been working on partitioned tables recently, and I have noticed
> something that doesn't seem correct with the EXPLAIN output of an
> update/delete query with a returning list.

What do you think is not right exactly? The output has to use some
one of the correlation names for the partitioned table. I think
it generally chooses the one corresponding to the first Append arm,
but really any would be good enough for EXPLAIN's purposes.

> 1. In the 'grouping_planner()' function, while generating paths for the
> final relation (
> https://github.com/postgres/postgres/blob/master/src/backend/optimizer/plan/planner.c#L1857)
> we only take care of adjusting the append_rel_attributes in returningList
> for resultRelation. Shouldn't we do that for other relations as well in
> query?

If the only difference is which way variables get labeled in EXPLAIN,
I'd be kind of disinclined to spend extra cycles. But in any case,
I rather suspect you'll find that this actively breaks things.
Whether we change the varno on a Var isn't really optional, and there
are cross-checks in setrefs.c to make sure things match up.

regards, tom lane