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Home -> Community -> Mailing Lists -> Oracle-L -> RE: The CBO Lie Detector
Bingo. Looks like they formalized a paper in Jan, 2003. And Oracle is
doing... what?
From: Job Miller [mailto:jobmiller_at_yahoo.com]
Sent: Friday, June 09, 2006 12:42 PM
To: Christian.Antognini_at_trivadis.com; Schultz, Charles
Cc: oracle-l_at_freelists.org; Wolfgang Breitling
Subject: RE: The CBO Lie Detector
Isn't this what DB2 claims LEO already does? I had to take a class once taught by an ex-IBM Autonomic Computing guy who required I learn about LEO.
"In this paper we introduce LEO, DB2's
LEarning Optimizer, as a comprehensive way to repair
incorrect statistics and cardinality estimates of a query
execution plan. By monitoring previously executed
queries, LEO compares the optimizer's estimates with
actuals at each step in a QEP, and computes
adjustments to cost estimates and statistics that may be
used during future query optimizations. This analysis
can be done either on-line or off-line on a separate
system, and either incrementally or in batches. In this
way, LEO introduces a feedback loop to query
optimization that enhances the available information on
the database where the most queries have occurred,
allowing the optimizer to actually learn from its past
mistakes."
Job Miller
oracle-l-bounce_at_freelists.org wrote:
Charles
>* I have to make a small disclaimer that I have not fully read
the
>paper, yet. I have only found an abstract, and am still looking
for the
>full thing. I did not find it on the OakTable.net or hotsos,
but am
>going through the rest of my google hits.
You find Wolfgang's paper on his homepage (www.centrexcc.com).
HTH Chris -- http://www.freelists.org/webpage/oracle-l __________________________________________________Do You Yahoo!?
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Jun 09 2006 - 12:55:34 CDT
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