Re: Buffer cache statistics (ratios) and CBO SQL optimization?

From: Noons <wizofoz2k_at_yahoo.com.au.nospam>
Date: Tue, 30 Dec 2003 13:07:38 +1100
Message-ID: <3ff0ddb7$2$18746$afc38c87@news.optusnet.com.au>

"Geomancer" <pharfromhome_at_hotmail.com> wrote in message news:cf90fb89.0312291731.e99c969_at_posting.google.com...
> > well they do until you saturate it (30 mins after boot :( ).
>
> If I have a 4-gig cacje on top of a 100 gig EMC array, then I only get
> 4% caching, right?

So, all caches are useless? Familiar with the expression "working set"? Read my reply to Niall.

> I still find it hard to beleive that a logical I/O is only 10x-100x
> faster than a disk read.

and in most modern installations, a LOT less than that. Courtesy of those 4G caches...

-- 
Cheers
Nuno Souto
wizofoz2k_at_yahoo.com.au.nospam

Received on Mon Dec 29 2003 - 20:07:38 CST