RE: db_file_multiblock_read_count and performance
- From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
- To: <Oracle-L@xxxxxxxxxxxxx>
- Date: Tue, 7 Dec 2004 14:16:58 -0600
If anyone is vague on the distinction between "performance" and
"scalability," I wrote a paper called "Scalability is a rate of change" a
few years ago to help clarify.
You can find it at www.hotsos.com.
Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
* Nullius in verba *
Upcoming events:
- Performance Diagnosis 101: 1/4 Calgary
- SQL Optimization 101: 12/13 Atlanta
- Hotsos Symposium 2005: March 6-10 Dallas
- Visit www.hotsos.com for schedule details...
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Jared Still
Sent: Tuesday, December 07, 2004 2:07 PM
To: Post, Ethan
Cc: Christian.Antognini@xxxxxxxxxxxx; ryan_gaffuri@xxxxxxxxxxx;
Oracle-L@xxxxxxxxxxxxx
Subject: Re: db_file_multiblock_read_count and performance
Don't forget 'as scalable as possible'.
Check the stats I posted earlier.
On Tue, 7 Dec 2004 13:19:19 -0600, Post, Ethan <Ethan.Post@xxxxxx> wrote:
> I would think ideal is "as fast as possible" and assuming you tell
> Oracle the truth about speed of multiblock reads verse single block with
> optimizer_index_cost_adj everything should work out fine, even if full
> scans are favored. Of course too many scans at the same time and
> optimizer_index_cost_adj is no longer valid because IO bandwidth may
> effect response times, so I guess this is where system stats has a
> supreme advantage.
>
>
--
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
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