Date: Wed, 24 Aug 2005 01:29:42 +0200
To: "William Yu" <wyu@talisys.com>, pgsql-performance@postgresql.org
Subject: Re: Caching by Postgres
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	<20050823124323.710a9dd3.frank@wiles.org>
	<430B6DE3.6040109@sun.com> <deg68k$16gh$1@news.hub.org>
From: PFC <lists@boutiquenumerique.com>
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> Josh Berkus has already mentioned this as conventional wisdom as written  
> by Oracle. This may also be legacy wisdom. Oracle/Sybase/etc has been  
> around for a long time; it was probably a clear performance win way back  
> when. Nowadays with how far open-source OS's have advanced, I'd take it  
> with a grain of salt and do my own performance analysis. I suspect the  
> big vendors wouldn't change their stance even if they knew it was no  
> longer true due to the support hassles.

	Reinvent a filesystem... that would be suicidal.

	Now, Hans Reiser has expressed interest on the ReiserFS list in tweaking  
his Reiser4 especially for Postgres. In his own words, he wants a "Killer  
app for reiser4". Reiser4 will offser transactional semantics via a  
special reiser4 syscall, so it might be possible, with a minimum of  
changes to postgres (ie maybe just another sync mode besides fsync,  
fdatasync et al) to use this. Other interesting details were exposed on  
the reiser list, too (ie. a transactional filesystems can give ACID  
guarantees to postgres without the need for fsync()).

	Very interesting.