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@sss.pgh.pa.us> 
Sent: Monday, January 30, 2023 11:30 AM
To: Joe Conway <mail@joeconway.com>
Cc: Bruce Momjian <bruce@momjian.us>; Pete Storer <Pete.Storer@sas.com>; pgsql-bugs@lists.postgresql.org
Subject: Re: FW: Query execution failure

EXTERNAL

Joe Conway <mail@joeconway.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