From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: "Jonathan S. Katz" <jkatz@postgresql.org>, Noah Misch <noah@leadboat.com>,
        Andrew Dunstan <andrew@dunslane.net>,
 Bruce Momjian <bruce@momjian.us>,
        Michael Paquier <michael@paquier.xyz>,
        Justin Pryzby <pryzby@telsasoft.com>,
        "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>,
        Shruthi Gowda <gowdashru@gmail.com>
Subject: Re: pg15b2: large objects lost on upgrade
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Wed, 03 Aug 2022 09:59:40 -0400"
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Date: Wed, 03 Aug 2022 10:13:51 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> On Tue, Aug 2, 2022 at 3:51 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I also think that ">=" is a sufficient requirement.

> I don't really like this approach. Imagine that the code got broken in
> such a way that relfrozenxid and relminmxid were set to a value chosen
> at random - say, the contents of 4 bytes of unallocated memory that
> contained random garbage. Well, right now, the chances that this would
> cause a test failure are nearly 100%. With this change, they'd be
> nearly 0%.

If you have a different solution that you can implement by, say,
tomorrow, then go for it.  But I want to see some fix in there
within about 24 hours, because 15beta3 wraps on Monday and we
will need at least a few days to see if the buildfarm is actually
stable with whatever solution is applied.

A possible compromise is to allow new values that are between
old value and old-value-plus-a-few-dozen.

			regards, tom lane