RE: FW: Query execution failure

This is very interesting, guys. And it leads me to a question: Is there any way to FORCE Postgres to do a local sort/collation of any data that is accessed through a FDW?

-----Original Message-----
From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Sent: Monday, January 30, 2023 11:30 AM
To: Joe Conway <mail(at)joeconway(dot)com>
Cc: Bruce Momjian <bruce(at)momjian(dot)us>; Pete Storer <Pete(dot)Storer(at)sas(dot)com>; pgsql-bugs(at)lists(dot)postgresql(dot)org
Subject: Re: FW: Query execution failure

EXTERNAL

Joe Conway <mail(at)joeconway(dot)com> writes:
> Also I have been told (not verified by me) that MySQL at least
> supports using its own built-in collation. If so, how can we ever know
> that whatever Postgres is using will match that?

Ugh. mysql_fdw probably ought to default to no-sort-pushdown.

> I wonder if we should have an attribute of a foreign server that
> indicates whether sort pushdown is enabled or not.

This is something that would have to be implemented individually by each FDW for which it's relevant. We could set a good precedent, and perhaps standardize the option name, by doing that in postgres_fdw.

regards, tom lane