Re: Possible bug in vacuum redo

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp>, Vadim Mikheev <vmikheev(at)sectorbase(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Possible bug in vacuum redo
Date: 2002-01-03 05:53:54
Message-ID: 200201030553.g035rsj14062@candle.pha.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Tom Lane wrote:
> Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp> writes:
> > In READ COMMITTED mode, an app searches valid tuples first
> > using the snapshot taken when the query started. It never
> > searches already updated(to newer ones) and committed tuples
> > at the point when the query started. Essentially t_ctid is
> > only needed by the concurrently running backends.
>
> [ thinks for awhile ] I see: you're saying that t_ctid is only
> used by transactions that are concurrent with the deleting transaction,
> so if there's a database crash there's no need to restore t_ctid.
>
> Probably true, but still mighty ugly.
>
> Meanwhile, I guess I gotta look elsewhere for a theory to explain
> those reports of duplicate rows. Oh well...

Can someone document this in the sources somewhere? I am not sure how
to do it.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Bruce Momjian 2002-01-03 06:11:14 Re: Status on RC1?
Previous Message Bruce Momjian 2002-01-03 05:39:34 Re: ADD PRIMARY KEY and ADD UNIQUE