Re: Veritas Quick I/0 and Oracle/ Asycnchronous I/O

Kevin's point is probably, that if each index has a depth (blevel) of three, then each index will add three LIO's to any DELETE or INSERT statement. For UPDATE statements, only the indexes on the updated columns count. LIO's mean cpu usage and latch pressure, which is why we want to mininize them in many situations.

"Mohan, Ross" wrote:

> I suspect, as with most 'rules of thumb', that Kevin's
> does not scale well.
>
> || -----Original Message-----
> || From: Henry Poras [mailto:Henry.Poras_at_ctp.com]
> || Sent: Monday, June 11, 2001 4:42 PM
> || To: Multiple recipients of list ORACLE-L
> || Subject: RE: Veritas Quick I/0 and Oracle/ Asycnchronous I/O
> ||
> ||
> || Let's see. What was that rule of thumb I heard from Kevin
> || Loney? I think it
> || was that each index slows down DML by a factor of 3 (at
> || least for batch jobs
> || where you have to worry about recursive SQL). So 23 indexes
> || would run about
> || 70 times slower than no indexes. Do I sense a hardware
> || throwing contest??
> ||
> || Henry
> ||
> || -----Original Message-----
> || Sent: Monday, June 11, 2001 4:01 PM
> || To: Multiple recipients of list ORACLE-L
> ||
> ||
> || On Monday 11 June 2001 09:06, Rachel Carmichael wrote:
> || > OLTP system, main order table had 23 indexes on it.
> || Because they wanted to
> ||
> || ?!?!?!
> ||
> || That's just nuts.
> ||
> || > be able to search by customer first name, customer last
> || name, recipient
> || > first name, recipient last name .... and had foreign keys
> || all over the
> || > place.
> ||
> || Sounds like Data Mart was a term they were unfamiliar with.
> ||
> || Jared
> || --
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> || Author: Henry Poras
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> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Mohan, Ross
> INET: MohanR_at_STARS-SMI.com
>
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--
Venlig hilsen

Mogens Nørgaard

Technical Director
Miracle A/S, Denmark
Web: http://MiracleAS.dk
Mobile: +45 2527 7100


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