Date: Wed, 11 Mar 2026 20:28:14 -0700
From: Mark Wong <markwkm@gmail.com>
To: =?iso-8859-1?Q?=C1lvaro?= Herrera <alvherre@kurilemu.de>
Cc: Chao Li <li.evan.chao@gmail.com>, pgsql-hackers@lists.postgresql.org
Subject: Re: updates for handling optional argument in system functions
Message-ID: <abIyzgOLlB2rpPBP@o>
References: <aXv4FjR1RTr386D1@o>
 <202603031619.ih6a6v4k6hd6@alvherre.pgsql>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <202603031619.ih6a6v4k6hd6@alvherre.pgsql>
Archived-At: <https://www.postgresql.org/message-id/abIyzgOLlB2rpPBP%40o>
Precedence: bulk

On Tue, Mar 03, 2026 at 05:23:58PM +0100, Álvaro Herrera wrote:
> On 2026-Jan-29, Mark Wong wrote:
> 
> > I don't have a solution for the case of a view storing the OID, but Álvaro
> > Herrera suggested to me to at least try preventing those OIDs from being
> > reused.
> > 
> > I've attached a v3 patch set that introduces src/include/catalog/pg_retired.dat
> > to store previously used OIDs and procedure names that the scripts unused_oids
> > and renumber_oids.pl can consume to prevent the reuse of retired OIDs.
> 
> Thinking about this again, I wonder where did we get the idea that
> reusing OIDs would be a problem.  How exactly would this happen?  When
> you pg_upgrade, your views are taken from a `pg_dump --binary-upgrade`
> of the original server, and then recreated using the text
> representation of the DDL.  We don't pass the function OIDs in any way
> from the old server to the new server.  And there's no other way (than
> pg_upgrade) to go from one major version to the next one where the OID
> has been reused.
> 
> So why did we think this was an actual problem?

I'm not sure.  I think I see the OID of a function get used in some places
likes rewriteDefine.c and parse_funcs.c, but I'm not sure if I see a function
OID get written out and re-read for a function name lookup in an upgrade code
path, yet...

Regards,
Mark
-- 
Mark Wong <markwkm@gmail.com>
EDB https://enterprisedb.com