From: Tom Lane <tgl@sss.pgh.pa.us>
To: Joe Conway <mail@joeconway.com>
cc: Bruce Momjian <bruce@momjian.us>, Pete Storer <Pete.Storer@sas.com>,
        "pgsql-bugs@lists.postgresql.org" <pgsql-bugs@lists.postgresql.org>
Subject: Re: FW: Query execution failure
In-reply-to: <f0c0bfec-0571-8711-deee-f6e679846c18@joeconway.com>
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 <BL0PR05MB66282D22D96AB745FBBD521FF3CF9@BL0PR05MB6628.namprd05.prod.outlook.com>
 <2961799.1674749201@sss.pgh.pa.us> <Y9fjfNpP7HZh1YX9@momjian.us>
 <f0c0bfec-0571-8711-deee-f6e679846c18@joeconway.com>
Comments: In-reply-to Joe Conway <mail@joeconway.com>
	message dated "Mon, 30 Jan 2023 11:16:03 -0500"
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Date: Mon, 30 Jan 2023 11:29:33 -0500
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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