Feedback-ID: ia2694551:Fastmail
Date: Mon, 4 Nov 2024 15:19:26 +0100
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>,
	Heikki Linnakangas <hlinnaka@iki.fi>, Pavel Borisov <pashkin.elfe@gmail.com>,
	Peter Eisentraut <peter@eisentraut.org>,
 pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: pgsql: Implement pg_wal_replay_wait() stored procedure
Message-ID: <202411041419.qif3lqaisktw@alvherre.pgsql>
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On 2024-Nov-04, Alexander Korotkov wrote:

> On Mon, Nov 4, 2024 at 8:04 AM Michael Paquier <michael@paquier.xyz> wrote:

> > Using output parameters in a procedure is something I did not recall.
> > Based on your point about not using a function due your argument based
> > on the snapshots, let's just use that and forget about the status
> > function entirely (please?).
> 
> Please, check [1].  Usage of output parameters is a bit awkward too,
> because you need to pass some value in there.  And more importantly,
> usage of output parameters also causes snapshot problem, as it causes
> another snapshot to be held.

I wonder if it would be better to go back to the original idea of using
special DDL syntax rather than a procedure.  It seems we've been piling
up hacks to get around the behavior of procedures, and we seem to have
grown one more to handle repeatable read transactions.

It's looking to me like there's just too much cruft in the quest to
avoid having to reach consensus on new syntax.  This might be a mistake.
Is it possible to backtrack on that decision?

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/
"Linux transformó mi computadora, de una `máquina para hacer cosas',
en un aparato realmente entretenido, sobre el cual cada día aprendo
algo nuevo" (Jaime Salinas)