Re: Anywy to accurately predict time for long running queries?

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Tue, 10 Feb 2004 20:08:26 -0000
Message-ID: <005801c3f011$a6d800f0$6702a8c0@Primary>

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

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Original Message ----- From: <ryan.gaffuri_at_cox.net> To: <oracle-l_at_freelists.org> 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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Received on Tue Feb 10 2004 - 14:08:26 CST