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: 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>, Tom Lane <tgl@sss.pgh.pa.us>, Stephen Frost <sfrost@snowman.net>
Date: 2020-08-28T14:08:55Z
Lists: pgsql-hackers 
On Fri, Aug 28, 2020 at 5:55 AM Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
> We can certainly do this way, but I would still prefer having a comparator function (tidcmp) here for the reasons that it makes the code look a bit cleaner, it also makes us more consistent with the way the comparator function argument is being passed to qsort at several other places in postgres which kinda of increases the code readability and simplicity. For e.g. there is a comparator function for gin that does the same thing as tidcmp is doing here.

Me too. Casting one kind of function pointer to another kind of
function pointer assumes that the compiler is using the same
argument-passing conventions in both cases, which seems slightly
risky. It also means that if the signature for the function were to
diverge further from the signature that we need in the future, the
compiler might not warn us about it. Perhaps there is some case where
the performance gains would be sufficiently to justify those risks,
but this is certainly not that case.

-- 
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.