Re: Free Space Map data structure

From: Hannu Krosing <hannu(at)krosing(dot)net>
To: Heikki Linnakangas <heikki(at)enterprisedb(dot)com>
Cc: Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Free Space Map data structure
Date: 2008-04-09 20:55:18
Message-ID: 1207774518.6560.4.camel@huvostro
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On Wed, 2008-04-09 at 21:09 +0300, Heikki Linnakangas wrote:
> Hannu Krosing wrote:
> > Saving 1 byte is an atomic op
>
> Unfortunately, it's not. Most if not all modern CPUs will perform one
> byte modification as "load word" + "modify word" + "save word".

Hmm, maybe we I should change my design to modify page free info and its
parent together ?

or what is word ? 2 bytes ? 4 bytes ? even 8 bytes ?

------------
Hannu

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