Horton

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

x4mmm@yandex-team.ru

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From: "Andrey M. Borodin" <x4mmm@yandex-team.ru>
To: Ashutosh Sharma <ashu.coek88@gmail.com>
Cc: 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>, Robert Haas <robertmhaas@gmail.com>
Date: 2020-07-31T14:57:22Z
Lists: pgsql-hackers 

> 31 июля 2020 г., в 17:32, Ashutosh Sharma <ashu.coek88@gmail.com> написал(а):
> 
> 
> On Wed, Jul 29, 2020 at 9:58 AM Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
> 
> > I think we should let VACUUM do that.
> Sometimes VACUUM will not get to these pages, because they are marked All Frozen.
> An possibly some tuples will get stale on this page again
> 
> Hmm, okay, will have a look into this. Thanks.
> 
> I had a look over this and found that one can use the DISABLE_PAGE_SKIPPING option with VACUUM to disable all its page-skipping behavior.

Oh, wow, I didn't know that. Thanks! This actually will do the trick.
I'll try to review your patch again next week.

Thanks!

Best regards, Andrey Borodin.

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.