Horton

Re: pg15b2: large objects lost on upgrade

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Jonathan S. Katz" <jkatz@postgresql.org>
Cc: Noah Misch <noah@leadboat.com>, Robert Haas <robertmhaas@gmail.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>
Date: 2022-08-02T19:32:05Z
Lists: pgsql-hackers

Commits

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  1. Revert recent changes to 002_pg_upgrade.pl.

  2. Revise test case added in 43746996399541ecb5c7b188725a5f097c15ceae.

  3. Use TRUNCATE to preserve relfilenode for pg_largeobject + index.

  4. Preserve relfilenode of pg_largeobject and its index across pg_upgrade.

  5. Have VACUUM warn on relfrozenxid "in the future".

  6. Set relfrozenxid to oldest extant XID seen by VACUUM.

  7. pg_upgrade: Preserve relfilenodes and tablespace OIDs.

  8. Perform a lot more sanity checks when freezing tuples.

"Jonathan S. Katz" <jkatz@postgresql.org> writes:
> On 8/2/22 1:12 PM, Tom Lane wrote:
>> Sadly, we're still not out of the woods.  I see three buildfarm
>> failures in this test since Robert resolved the "-X" problem [1][2][3]:

> Looking at the test code, is there anything that could have changed the 
> relfrozenxid or relminxid independently of the test on these systems?

Hmmm ... now that you mention it, I see nothing in 002_pg_upgrade.pl
that attempts to turn off autovacuum on either the source server or
the destination.  So one plausible theory is that autovac moved the
numbers since we checked.

If that is the explanation, then it leaves us with few good options.
I am not in favor of disabling autovacuum in the test: ordinary
users are not going to do that while pg_upgrade'ing, so it'd make
the test less representative of real-world usage, which seems like
a bad idea.  We could either drop this particular check again, or
weaken it to allow new relfrozenxid >= old relfrozenxid, likewise
relminxid.

			regards, tom lane