Horton

Re: pg15b2: large objects lost on upgrade

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: Justin Pryzby <pryzby@telsasoft.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Shruthi Gowda <gowdashru@gmail.com>
Date: 2022-07-07T18:38:44Z
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 Thu, Jul 7, 2022 at 2:24 PM Bruce Momjian <bruce@momjian.us> wrote:
> On Thu, Jul  7, 2022 at 01:38:44PM -0400, Robert Haas wrote:
> > On Thu, Jul 7, 2022 at 1:10 PM Justin Pryzby <pryzby@telsasoft.com> wrote:
> > > Maybe it's a good idea to check that the file is empty before unlinking...
> >
> > If we want to verify that there are no large objects in the cluster,
> > we could do that in check_new_cluster_is_empty(). However, even if
> > there aren't, the length of the file could still be more than 0, if
> > there were some large objects previously and then they were removed.
> > So it's not entirely obvious to me that we should refuse to remove a
> > non-empty file.
>
> Uh, that initdb-created pg_largeobject file should not have any data in
> it ever, as far as I know at that point in pg_upgrade.  How would values
> have gotten in there?  Via pg_dump?

I was thinking if the user had done it manually before running pg_upgrade.

-- 
Robert Haas
EDB: http://www.enterprisedb.com