From: Pavan Deolasee <pavan.deolasee@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: John Lister <john.lister-ps@kickstone.com>
Cc: pgsql-hackers@postgresql.org
Subject: Re: Database corruption help
Date: Wed, 25 Feb 2009 23:12:31 +0530
Message-ID: <2e78013d0902250942u7d6103fev96e3b6d4eb20e5b8@mail.gmail.com> (raw)
In-Reply-To: <3161.1234541940@sss.pgh.pa.us>
References: <507152DDF8AB4DF093BD01A8BEC7C659@squarepi.com>
<25753.1234224090@sss.pgh.pa.us>
<4991338B.704@kickstone.com>
<4994906B.6090408@kickstone.com>
<17204.1234474784@sss.pgh.pa.us>
<4994987F.1030204@kickstone.com>
<17764.1234476783@sss.pgh.pa.us>
<4994A45B.4030707@kickstone.com>
<49952D33.3000707@kickstone.com>
<3161.1234541940@sss.pgh.pa.us>
On Fri, Feb 13, 2009 at 9:49 PM, Tom Lane <tgl@sss.pgh.pa.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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To: pgsql-admin@postgresql.org
Cc: pavan.deolasee@gmail.com, tgl@sss.pgh.pa.us, john.lister-ps@kickstone.com, pgsql-hackers@postgresql.org
Subject: Re: Database corruption help
In-Reply-To: <2e78013d0902250942u7d6103fev96e3b6d4eb20e5b8@mail.gmail.com>
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