Message-ID: <a15cd7f9ca70a35b61faa38eccea9a7d41bdb3c2.camel@j-davis.com>
Subject: Re: New strategies for freezing, advancing relfrozenxid early
From: Jeff Davis <pgsql@j-davis.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Matthias van de Meent <boekewurm+postgres@gmail.com>, John Naylor
 <john.naylor@enterprisedb.com>, Andres Freund <andres@anarazel.de>, Justin
 Pryzby <pryzby@telsasoft.com>, PostgreSQL Hackers
 <pgsql-hackers@lists.postgresql.org>
Date: Wed, 21 Dec 2022 16:30:28 -0800
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On Tue, 2022-12-20 at 21:26 -0800, Peter Geoghegan wrote:
> When freeze_required is set to true, that means that lazy_scan_prune
> literally has no choice -- it simply must freeze the page as
> instructed by heap_prepare_freeze_tuple/FreezeMultiXactId. It's not
> just a strong suggestion -- it's crucial that lazy_scan_prune freezes
> the page as instructed.

The confusing thing to me is perhaps just the name -- to me,
"freeze_required" suggests that if it were set to true, it would cause
freezing to happen. But as far as I can tell, it does not cause
freezing to happen, it causes some other things to happen that are
necessary when freezing happens (updating and using the right
trackers).

A minor point, no need to take action here. Perhaps rename the
variable.

I think 0001+0002 are about ready.


--=20
Jeff Davis
PostgreSQL Contributor Team - AWS