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Re[2]: How to compare two different SQL executions plans (question is more deeper then seams from first look)?

From: Edgar Chupit <edgar.chupit_at_rs.lv>
Date: Wed, 30 Jun 2004 09:21:49 +0300
Message-ID: <1218980679.20040630092149@rs.lv>


Hello J,

JVal> But for CPU utilization we canít use LIOs statistics.

sure we can't, if it would be so simple, than optimizer wouldn't need to compute cost of each query, but simply estimate lio count. I think that you are trying to simplify things.

But for your questions, to get top sql's by cpu you need to sort by cpu_time, but you have to remember, that you want to get top sql over "problematic" period of time, who cares if "huge" query is running off-hours? So you need to check queries that had been run when critical business process was running.

For a second question, you may I think lio minimization rule still apply, but developers should consider to compare estimated cost of query and latches.

--

Best regards,
 Edgar



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Received on Wed Jun 30 2004 - 01:18:32 CDT

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