Horton

Re: pg15b2: large objects lost on upgrade

Bruce Momjian <bruce@momjian.us>

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From: Bruce Momjian <bruce@momjian.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: "Jonathan S. Katz" <jkatz@postgresql.org>, Noah Misch <noah@leadboat.com>, Robert Haas <robertmhaas@gmail.com>, Andrew Dunstan <andrew@dunslane.net>, Michael Paquier <michael@paquier.xyz>, Justin Pryzby <pryzby@telsasoft.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Shruthi Gowda <gowdashru@gmail.com>
Date: 2022-08-09T02:53:04Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  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.

On Mon, Aug  8, 2022 at 09:51:46PM -0400, Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> >> 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.
> 
> > Uh, pg_upgrade assumes autovacuum is not running, and tries to enforce
> > this:
> 
> The problems come from autovac running before or after pg_upgrade.
> 
> > Perhaps the test script should do something similar,
> 
> I'm not on board with that, for the reasons I gave upthread.

Uh, I assume it is this paragraph:

> 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.

I thought the test was setting up a configuration that would never be
used by normal servers.  Is that false?

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

  Indecision is a decision.  Inaction is an action.  Mark Batterson