Re: Database corruption help

From: Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: John Lister <john(dot)lister-ps(at)kickstone(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Database corruption help
Date: 2009-02-25 17:42:31
Message-ID: 2e78013d0902250942u7d6103fev96e3b6d4eb20e5b8@mail.gmail.com
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On Fri, Feb 13, 2009 at 9:49 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> The only other corruption mechanism I can think of is that pg_clog might
> contain commit bits for some logically inconsistent set of transaction
> numbers, due to some pages of pg_clog having made it to disk and others
> not.  That could result in some of the intermediate tuples in the chain
> not being seen as dead --- but that's not what we see here either.
>

Or can it be otherwise where some transactions which in fact
committed, are marked as aborted because of clog corruption ? In that
case, some of the intermediate tuples in the HOT chain may get removed
(because we handle aborted heap-only tuples separately) and break the
HOT chain.

I am also looking at the pruning logic to see if I can spot something unusual.

Thanks,
Pavan

--
Pavan Deolasee
EnterpriseDB http://www.enterprisedb.com

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