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: 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: 2020-08-27T02:26:21Z
Lists: pgsql-hackers 
On Wed, Aug 26, 2020 at 9:19 PM Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Wed, Aug 26, 2020 at 7:36 AM Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
> > Removed this note from the documentation and added a note saying: "The
> > user needs to ensure that they do not operate pg_force_freeze function
> > on a deleted tuple because it may revive the deleted tuple."
>
> I do not agree with that note, either. I believe that trying to tell
> people what things specifically they should do or avoid doing with the
> tool is the wrong approach. Instead, the thrust of the message should
> be to tell people that if you use this, it may corrupt your database,
> and that's your problem. The difficulty with telling people what
> specifically they ought to avoid doing is that experts will be annoyed
> to be told that something is not safe when they know that it is fine,
> and non-experts will think that some uses are safer than they really
> are.
>

Okay, point noted.

Thanks,

--
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.