pg.ddx.io  pgsql-hackers@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Noah Misch <noah@leadboat.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Smolkin Grigory <smallkeen@gmail.com>
Cc: pgsql-hackers@postgresql.org
Subject: Re: race condition in pg_class
Date: Mon, 13 May 2024 13:30:38 -0700
Message-ID: <20240513203038.d7.nmisch@google.com> (raw)
In-Reply-To: <CA+TgmoZocjvRKB5Rv-8oJ5=-FVaSeFSUCC5C3HN2ZPjgZPS=jA@mail.gmail.com>
References: <CAMp+ueZQz3yDk7qg42hk6-9gxniYbp-=bG2mgqecErqR5gGGOA@mail.gmail.com>
	<20231027044404.7e.nmisch@google.com>
	<20231027184832.9b.nmisch@google.com>
	<1596629.1698435146@sss.pgh.pa.us>
	<20231027214946.79.nmisch@google.com>
	<1617596.1698446455@sss.pgh.pa.us>
	<20231027232612.99.nmisch@google.com>
	<20231102030915.d3.nmisch@google.com>
	<20240512232923.aa.nmisch@google.com>
	<CA+TgmoZocjvRKB5Rv-8oJ5=-FVaSeFSUCC5C3HN2ZPjgZPS=jA@mail.gmail.com>

On Mon, May 13, 2024 at 03:53:08PM -0400, Robert Haas wrote:
> On Sun, May 12, 2024 at 7:29 PM Noah Misch <noah@leadboat.com> wrote:
> > - [consequences limited to transient failure] Since a PROC_IN_VACUUM backend's
> >   xmin does not stop pruning, an MVCC scan in that backend can find zero
> >   tuples when one is live.  This is like what all backends got in the days of
> >   SnapshotNow catalog scans.  See the pgbench test suite addition.  (Perhaps
> >   the fix is to make VACUUM do its MVCC scans outside of PROC_IN_VACUUM,
> >   setting that flag later and unsetting it earlier.)
> 
> Are you saying that this is a problem already, or that the patch
> causes it to start happening? If it's the former, that's horrible.

The former.





view thread (86+ messages)  latest in thread

Message-ID: <20240513203038.d7.nmisch@google.com>
Permalink:  ../20240513203038.d7.nmisch@google.com/
Also on:    postgresql.org/message-id/20240513203038.d7.nmisch@google.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-hackers@postgresql.org
  Cc: noah@leadboat.com, robertmhaas@gmail.com, tgl@sss.pgh.pa.us, smallkeen@gmail.com
  Subject: Re: race condition in pg_class
  In-Reply-To: <20240513203038.d7.nmisch@google.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox