Feedback-ID: ie3de48e3:Fastmail
Date: Mon, 20 Oct 2025 16:18:50 +0200
From: =?utf-8?Q?=C3=81lvaro?= Herrera <alvherre@kurilemu.de>
To: Matheus Alcantara <matheusssilv97@gmail.com>
Cc: Joel Jacobson <joel@compiler.org>,
	Arseniy Mukhin <arseniy.mukhin.dev@gmail.com>,
 Masahiko Sawada <sawada.mshk@gmail.com>,
	Rishu Bagga <rishu.postgres@gmail.com>,
 Yura Sokolov <y.sokolov@postgrespro.ru>,
	Daniil Davydov <3danissimo@gmail.com>,
 Alexandra Wang <alexandra.wang.oss@gmail.com>,
	pgsql-hackers <pgsql-hackers@postgresql.org>, Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: LISTEN/NOTIFY bug: VACUUM sets frozenxid past a xid in async
 queue
Message-ID: <202510201414.56f2msqusjla@alvherre.pgsql>
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On 2025-Oct-20, Matheus Alcantara wrote:

> This is similar to what was already proposed at [1]. This approach was
> abandoned because a notification on the queue may block datfrozenxid
> advance and clog truncation which can cause other issues for the users [2].

Well, I think that this is the right solution for backpatching, and that
you were wrong to abandon it.  You can continue to design a better
mechanism for the master branch, but in old branches we cannot really do
all those things you're proposing to do.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"Cómo ponemos nuestros dedos en la arcilla del otro. Eso es la amistad; jugar
al alfarero y ver qué formas se pueden sacar del otro" (C. Halloway en
La Feria de las Tinieblas, R. Bradbury)