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Subject: Re: Granting SET and ALTER SYSTE privileges for GUCs
From: Mark Dilger <mark.dilger@enterprisedb.com>
In-Reply-To: <2227120.1637076727@sss.pgh.pa.us>
Date: Tue, 16 Nov 2021 07:45:14 -0800
Cc: Robert Haas <robertmhaas@gmail.com>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>,
 Andrew Dunstan <andrew@dunslane.net>
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To: Tom Lane <tgl@sss.pgh.pa.us>
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> On Nov 16, 2021, at 7:32 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>=20
> Mark Dilger <mark.dilger@enterprisedb.com> writes:
>> I don't think we support using a .so that is mismatched against the
>> version of the extension that is installed.
>=20
> You are entirely mistaken.  That's not only "supported", it's =
*required*.
> Consider binary upgrades, where the SQL objects are transferred as-is
> but the receiving installation may have a different (hopefully newer)
> version of the .so.  That .so has to cope with the older SQL object
> definitions; it doesn't get to assume that the upgrade script has been
> run yet.

You are talking about mismatches in the other direction, aren't you?  I =
was responding to Robert's point that new gucs could appear, and old =
gucs disappear.  That seems analogous to new functions appearing and old =
functions disappearing.  If you upgrade (not downgrade) the .so, the new =
gucs and functions will be in the .so, but won't be callable/grantable =
from sql until the upgrade script runs.  The old gucs and functions will =
be missing from the .so, and attempts to call them/grant them from sql =
before the upgrade will fail.  What am I missing here?

=E2=80=94
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company