Re: Free Space Map data structure

Hannu Krosing wrote:
> 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 ?

It depends on architecture, I believe it's 4 bytes on 32-bit 
architectures and 8 bytes on 64-bit ones, typically. But we have to work 
on all of them.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com