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Re: More tablescanning fun

From: Hannu Krosing <hannu(at)tm(dot)ee>
To: jim(at)nasby(dot)net
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-performance(at)postgresql(dot)org
Subject: Re: More tablescanning fun
Date: 2003-04-25 16:28:06
Message-ID: 1051288086.1765.95.camel@fuji.krosing.net (view raw or flat)
Thread:
Lists: pgsql-performance
Jim C. Nasby kirjutas R, 25.04.2003 kell 07:59:
> > > Also, is there a TODO to impliment
> > > real clustered indexes?
> > 
> > No.  It's not apparent to me how you could do that without abandoning
> > MVCC, which we're not likely to do.
>  
> Hmm... does MVCC mandate inserts go at the end? 

I have been pondering if keeping pages half-empty (or even 70% empty)
could solve both clustering problems and longish updates for much data.

If we could place the copy in the same page than original, most big
updates would be possible by one sweep of disk heads and also clustering
order would be easier to keep if pages were kept intentionally half
empty.

So "VACUUM FULL 65% EMPTY;" could make sense ?


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


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