Horton

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

Ashutosh Sharma <ashu.coek88@gmail.com>

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From: Ashutosh Sharma <ashu.coek88@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, "Andrey M. Borodin" <x4mmm@yandex-team.ru>, MBeena Emerson <mbeena.emerson@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Andres Freund <andres@anarazel.de>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, Stephen Frost <sfrost@snowman.net>
Date: 2020-08-25T04:43:38Z
Lists: pgsql-hackers 
On Mon, Aug 24, 2020 at 7:15 PM Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Tue, Aug 18, 2020 at 12:14 PM Alvaro Herrera
> <alvherre@2ndquadrant.com> wrote:
> > It makes sense to recommend VACUUM after fixing the page, but I agree
> > with Sawada-san that it would be sensible to reset the VM bit while
> > doing surgery, since that's the state that the page would be in.  We
> > should certainly *strongly recommend* to do VACUUM DISABLE_PAGE_SKIPPING,
> > but if users fail to do so, then leaving the VM bit set just means that
> > we know *for certain* that there will be further corruption as soon as
> > the XID counter advances sufficiently.
>
> +1.
>

This has been taken care of in the latest v7 patch.

--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com

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.