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Re: Cause of missing pg_clog files

From: Justin Clift <justin(at)postgresql(dot)org>
To: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Cause of missing pg_clog files
Date: 2002-09-30 14:37:13
Message-ID: 3D986199.37863C69@postgresql.org (view raw or flat)
Thread:
Lists: pgsql-hackers
Bruce Momjian wrote:
> 
> OK, we need a decision on whether we are going to do a 7.2,3 or just
> have it in beta3.  If it is in 7.2.3, I would not mention it in the
> beta3 release notes.

We definitely should have a 7.2.3.  If we can release a 7.2.2 to fix
bugs and a security flaw, then we should definitely have a 7.2.3 to
ensure the usability of the 7.2.x series.

Some places will still be using 7.2.x for 2 years to come, just because
7.2.x was what their projects started developing against, etc.

:-)

Regards and best wishes,

Justin Clift

 
> ---------------------------------------------------------------------------
> 
> Tom Lane wrote:
> > Yesterday I reported a WAL problem that could lead to tuples not being
> > marked as committed-good or committed-dead after we'd already removed
> > the pg_clog segment that had their transaction's commit status.
> > I wasn't completely satisfied with that, though, because on further
> > reflection it seemed a very low-probability mechanism.  I kept digging,
> > and finally came to the kind of bug that qualifies as a big DOH :-(
> >
> > If you run a database-wide VACUUM (one with no specific target table
> > mentioned) as a non-superuser, then the VACUUM doesn't process tables
> > that don't belong to you.  But it will advance pg_database.datvacuumxid
> > anyway, which means that pg_clog could be truncated while old transaction
> > references still remain unmarked in those other tables.
> >
> > In words of one syllable: running VACUUM as a non-superuser can cause
> > irrecoverable data loss in any 7.2.* release.
> >
> > I think this qualifies as a "must fix" bug.  I recommend we back-patch
> > a fix for this into the REL7_2 branch and put out a 7.2.3 release.
> > We should also fix the "can't wait without a PROC" bug that was solved
> > a few days ago.
> >
> >                       regards, tom lane
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 6: Have you searched our list archives?
> >
> > http://archives.postgresql.org
> >
> 
> --
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 359-1001
>   +  If your life is a hard drive,     |  13 Roberts Road
>   +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
> 
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