Horton

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

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Ashutosh Sharma <ashu.coek88@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Mark Dilger <mark.dilger@enterprisedb.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>, Stephen Frost <sfrost@snowman.net>
Date: 2020-09-15T19:36:22Z
Lists: pgsql-hackers 
On Mon, Sep 14, 2020 at 6:26 AM Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
> Thanks for reporting. I'm able to reproduce the issue by creating some
> delay just before "-- now create an unused line pointer" and use the
> delay to start a new session either with repeatable read or
> serializable transaction isolation level and run some query on the
> test table. To fix this, as you suggested I've converted the test
> table to the temp table. Attached is the patch with the changes.
> Please have a look and let me know about any concerns.

Tom, do you have any concerns about this fix?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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.