Why "multiple of 5" blocks --- was Re: buffer cache -once again

Jonathan,

Just curious [and I may have read this earlier but have forgotten it if I have done so ..]
where did the "multiple of 5" blocks rule come from. It's been around since, what Oracle6 ? Why not "multiple of 4" which is a power of 2. [or did they want an extra block as a header block ?] Hemant

At 02:41 PM 12-05-03 -0800, you wrote:

>Just a throwaway idea - if you set a 128K extent
>size (minimum extent length, or initial = next)
>on an 8K block size, then oracle would round
>up to the next multiple of 5 blocks - which would
>be 160K - viz 20 blocks.
>
>
>Jonathan Lewis
>http://www.jlcomp.demon.co.uk
>
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>----- Original Message -----
>To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
>Sent: 12 May 2003 17:27
>
>
> >
> > This is on several SAP systems with DD managed extents.
> >
> > Std extent size? What's that? ;)
> >
> > I'll run it again to be sure, I could be misrembering the results.
> >
> > Jared
> >
> > On Sunday 11 May 2003 02:16, Niall Litchfield wrote:
> > > No.
> > >
> > > On a SAN attached Compaq box at work I get 128, which with an 8k
>block
> > > size, is = 1mb or SSTIOMAX. My box at home has a max effective and
> > > achieved MBRC of 64 (or 512k). 20 blocks isn't a standard extent
>size
> > > for you by any chance?
> > >
>
>
>--
>Please see the official ORACLE-L FAQ: http://www.orafaq.net
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>Author: Jonathan Lewis
> INET: jonathan_at_jlcomp.demon.co.uk
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Hemant K Chitale
My personal web site is : http://hkchital.tripod.com

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