Re: recovering from "found xmin ... from before relfrozenxid ..."

Michael Banck <michael.banck@credativ.de>

From: Michael Banck <michael.banck@credativ.de>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andrey Borodin <x4mmm@yandex-team.ru>, Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Amit Kapila <amit.kapila16@gmail.com>, Ashutosh Sharma <ashu.coek88@gmail.com>, Mark Dilger <mark.dilger@enterprisedb.com>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, MBeena Emerson <mbeena.emerson@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Stephen Frost <sfrost@snowman.net>
Date: 2021-01-18T14:25:38Z
Lists: pgsql-hackers
On Mon, Jan 18, 2021 at 08:54:10AM -0500, Robert Haas wrote:
> On Sat, Jan 16, 2021 at 10:41 AM Andrey Borodin <x4mmm@yandex-team.ru> wrote:
> > Does anyone maintain opensource pg_surgery analogs for released
> > versions of PG?  It seems to me I'll have to use something like this
> > and I just though that I should consider pg_surgery in favour of our
> > pg_dirty_hands.
> 
> I do not. I'm still of the opinion that we ought to back-patch
> pg_surgery. This didn't attract a consensus before, and it's hard to
> dispute that it's a new feature in what would be a back branch. But
> it's unclear to me how users are otherwise supposed to recover from
> some of the bugs that are or have been present in those back branches.

One other possiblity would be to push a version of pg_surgery that is
compatible with the back-branches somewhere external (e.g. either
git.postgresql.org and/or Github), so that it can be picked up by
distributions and/or individual users in need.

That is Assuming it does not need assorted server changes to go with; I
did not read the thread in detail but I was under the assumption it is a
client program?


Michael

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Commits

  1. Fix wrong data table horizon computation during backend startup.

  2. Centralize horizon determination for temp tables, fixing bug due to skew.

  3. pg_surgery: Try to stabilize regression tests.

  4. New contrib module, pg_surgery, with heap surgery functions.

  5. Set cutoff xmin more aggressively when vacuuming a temporary table.

  6. snapshot scalability: Don't compute global horizons while building snapshots.

  7. Introduce vacuum errcontext to display additional information.