From: Jean-David Beyer <jeandavid8@verizon.net>
To: pgsql performance <pgsql-performance@postgresql.org>
Subject: Re: Curious about dead rows.
Date: Wed, 14 Nov 2007 16:51:44 -0500
Message-ID: <473B6DF0.8020206@verizon.net> (raw)
In-Reply-To: <20071114213504.GW19014@alvh.no-ip.org>
References: <4735DBDB.5050208@verizon.net>
<473B4AB4.70506@sime.com>
<473B6398.9030507@verizon.net>
<20071114213504.GW19014@alvh.no-ip.org>
Alvaro Herrera wrote:
> Jean-David Beyer wrote:
>> Mario Weilguni wrote:
>
>>> Did you rollback some transactions? It will generate dead rows too - at
>>> least I think so.
>>>
>> No, and the statistics confirm this.
>
> To recap:
>
> - your app only does inserts
True.
> - there has been no rollback lately
True.
> - there are no updates
True
> - there are no deletes
True.
>
> The only other source of dead rows I can think is triggers ... do you
> have any?
No triggers at all. I have sequences that were not in the IBM DB2 version of
this stuff. But they are all done earlier, before the CLUSTER of the entire
database. Furthermore, they are only for two tables, not the ones that
attracted my notice in the first place.
> (Not necessarily on this table -- perhaps triggers on other
> tables can cause updates on this one).
>
> Oh, rolled back COPY can cause dead rows too.
>
The only copies I ever do are those inside dbdump -- dbrestore, and they
come after all this stuff. And they do not roll back -- though I suppose
they could in principle.
--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 16:45:01 up 22 days, 10:03, 1 user, load average: 4.20, 4.22, 4.17
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-performance@postgresql.org
Cc: jeandavid8@verizon.net
Subject: Re: Curious about dead rows.
In-Reply-To: <473B6DF0.8020206@verizon.net>
* 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