From: Markus Wanner <markus@bluegap.ch>
To: HMaelzer@buerotiger.de
Cc: PostgreSQL-development Hackers <pgsql-hackers@postgresql.org>
Subject: Re: [pgsql-cluster-hackers] Question: Can i cut NON-HOT chain Pointers if there are no concurrent updates?
Date: Fri, 23 Nov 2012 16:08:51 +0100
Message-ID: <50AF9183.3010308@bluegap.ch> (raw)
In-Reply-To: <20121123141759.121640@gmx.net>
References: <20121123141759.121640@gmx.net>
Henning,
On 11/23/2012 03:17 PM, "Henning Mälzer" wrote:
> Can somebody help me?
Sure, but you might get better answers on the -hackers mailing list. I'm
redirecting there. The cluster-hackers one is pretty low volume and low
subscribers, I think.
> Question:
> What would be the loss if i cut NON-HOT chain Pointers, meaning i set t_ctid=t_self in the case where it points to a tuple on another page?
READ COMMITTED would stop to work correctly in the face of concurrent
transactions, I guess. See the fine manual:
http://www.postgresql.org/docs/devel/static/transaction-iso.html#XACT-READ-COMMITTED
The problem essentially boils down to: READ COMMITTED transactions need
to learn about tuples *newer* than what their snapshot would see.
> I am working on a project based on "postgres (PostgreSQL) 8.5devel" with the code from several master thesises befor me.
Care to elaborate a bit? Can (part of) that code be released under an
open license?
Regards
Markus Wanner
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To: pgsql-hackers@postgresql.org
Cc: markus@bluegap.ch, HMaelzer@buerotiger.de
Subject: Re: [pgsql-cluster-hackers] Question: Can i cut NON-HOT chain Pointers if there are no concurrent updates?
In-Reply-To: <50AF9183.3010308@bluegap.ch>
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