Horton

Re: pg15b2: large objects lost on upgrade

Jonathan S. Katz <jkatz@postgresql.org>

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From: "Jonathan S. Katz" <jkatz@postgresql.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Geoghegan <pg@bowt.ie>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, 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>
Date: 2022-08-04T14:02:28Z
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.

Attachments

On 8/3/22 4:19 PM, Tom Lane wrote:
> "Jonathan S. Katz" <jkatz@postgresql.org> writes:
>> I did rule out wanting to do the "xid + $X" check after reviewing some
>> of the output. I think that both $X could end up varying, and it really
>> feels like a bandaid.
> 
> It is that.  I wouldn't feel comfortable with $X less than 100 or so,
> which is probably sloppy enough to draw Robert's ire.  Still, realizing
> that what we want right now is a band-aid for 15beta3, I don't think
> it's an unreasonable short-term option.

Attached is the "band-aid / sloppy" version of the patch. Given from the 
test examples I kept seeing deltas over 100 for relfrozenxid, I chose 
1000. The mxid delta was less, but I kept it at 1000 for consistency 
(and because I hope this test is short lived in this state), but can be 
talked into otherwise.

>> Andres suggested upthread using "txid_current()" -- for the comparison,
>> that's one thing I looked at. Would any of the XID info from
>> "pg_control_checkpoint()" also serve for this test?
> 
> I like the idea of txid_current(), but we have no comparable
> function for mxid do we?  While you could get both numbers from
> pg_control_checkpoint(), I doubt that's sufficiently up-to-date.

...unless we force a checkpoint in the test?

Jonathan