Received: from malur.postgresql.org ([217.196.149.56])
	by arkaria.postgresql.org with esmtps
 (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
	(Exim 4.92)
	(envelope-from <pgsql-docs-owner+archive@lists.postgresql.org>)
	id 1lzRDs-0005qF-9F
	for pgsql-docs@arkaria.postgresql.org; Fri, 02 Jul 2021 22:01:20 +0000
Received: from localhost ([127.0.0.1] helo=malur.postgresql.org)
	by malur.postgresql.org with esmtp (Exim 4.92)
	(envelope-from <pgsql-docs-owner+archive@lists.postgresql.org>)
	id 1lzRDr-0002lL-9I
	for pgsql-docs@arkaria.postgresql.org; Fri, 02 Jul 2021 22:01:19 +0000
Received: from makus.postgresql.org ([2001:4800:3e1:1::229])
	by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
	(Exim 4.92)
	(envelope-from <bruce@momjian.us>)
	id 1lzRDr-0002lB-3D
	for pgsql-docs@lists.postgresql.org; Fri, 02 Jul 2021 22:01:19 +0000
Received: from momjian.us ([72.94.173.45])
	by makus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
	(Exim 4.92)
	(envelope-from <bruce@momjian.us>)
	id 1lzRDp-0002op-0Q
	for pgsql-docs@lists.postgresql.org; Fri, 02 Jul 2021 22:01:18 +0000
Received: from bruce by momjian.us with local (Exim 4.92)
	(envelope-from <bruce@momjian.us>)
	id 1lzRDm-0000OV-2P; Fri, 02 Jul 2021 18:01:14 -0400
Date: Fri, 2 Jul 2021 18:01:14 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>, eric.mutta@gmail.com,
	pgsql-docs@lists.postgresql.org
Subject: Re: 24.1.5.1. Multixacts And Wraparound
Message-ID: <20210702220114.GD25522@momjian.us>
References: <20210624195329.GB16214@momjian.us>
 <202106242006.uyjdiujqk36b@alvherre.pgsql>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <202106242006.uyjdiujqk36b@alvherre.pgsql>
User-Agent: Mutt/1.10.1 (2018-07-13)
List-Id: <pgsql-docs.lists.postgresql.org>
List-Help: <https://lists.postgresql.org/manage/>
List-Subscribe: <https://lists.postgresql.org/manage/>
List-Post: <mailto:pgsql-docs@lists.postgresql.org>
List-Owner: <mailto:pgsql-docs-owner@lists.postgresql.org>
List-Archive: <https://www.postgresql.org/list/pgsql-docs>
Archived-At: 
 <https://www.postgresql.org/message-id/20210702220114.GD25522%40momjian.us>
Precedence: bulk

On Thu, Jun 24, 2021 at 04:06:38PM -0400, Álvaro Herrera wrote:
> On 2021-Jun-24, Bruce Momjian wrote:
> 
> > +     As a safety device, an aggressive vacuum scan will
> > +     occur for any table whose multixact-age (see <xref
> > +     linkend="vacuum-for-multixact-wraparound"/>) is greater than <xref
> > +     linkend="guc-autovacuum-multixact-freeze-max-age"/>.  Also, if the
> > +     storage occupied by multixacts exceeds 2GB, aggressive vacuum scans
> > +     will occur more often for all tables, starting with those that have
> > +     the oldest multixact-age.  Both of these kinds of aggressive scans
> > +     will occur even if autovacuum is nominally disabled.
> 
> This looks good, thanks.
> 
> I think "the space occupied by multixacts" is a bit ambiguous -- it is
> talking about pg_multixact/members only, but you could interpret that it
> talks about both that and pg_multixact/offsets.  I'm not sure we need to
> be 100% precise about that, so perhaps what you have is sufficient.  But
> if we do want to be precise, then maybe " ... if the storage occupied by
> multixact members (<literal>pg_multixact/members/</literal>) exceeds ..."
> covers it.
> 
> (At least, that's how I remember this.  I don't think things have
> changed much since 53bb309d2d5a ...)

OK, I got "members" into the doc section and applied it to master and PG
14.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  If only the physical world exists, free will is an illusion.