Re: Anywy to accurately predict time for long running queries?
- From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 10 Feb 2004 20:08:26 -0000
The "silly-season" answer to your question
is to run the query through explain plan, then
multiple by the calculated cost by the manufacturer's
quoted average I/O time.
The calculated cost of a query is the CBO's estimate
of time to completion in units of single block reads,
so any other method is trying to second guess the
optimizer.
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
The educated person is not the person
who can answer the questions, but the
person who can question the answers -- T. Schick Jr
Next public appearances:
March 2004 Hotsos Symposium - The Burden of Proof
March 2004 Charlotte NC OUG - CBO Tutorial
April 2004 Iceland
One-day tutorials:
http://www.jlcomp.demon.co.uk/tutorial.html
Three-day seminar:
see http://www.jlcomp.demon.co.uk/seminar.html
____UK___February
____UK___June
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
----- Original Message -----
From: <ryan.gaffuri@xxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Tuesday, February 10, 2004 1:09 PM
Subject: Anywy to accurately predict time for long running queries?
People here want me to accurately predict how long it will take long running
SQL to execute. I'm reading carrie milsap's book now, and I believe he has
some methods that give good estimates on overall performance(I have not
gotten to that part yet).
any known methods to accurately predict sql? BTW, I dont have specs on the
hardware, its a customer site... and yes I know you really need that.
I dont think this is doable, but im wondering if anyone has put together any
papers on the subject.
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