Re: full-scan vs index for "small" tables
- From: Nuno Souto <dbvision@xxxxxxxxxxxx>
- Date: Thu, 29 Jun 2006 00:20:41 +1000
Cary Millsap wrote,on my timestamp of 28/06/2006 11:44 PM:
RBO is dramatically inferior to CBO in every case except for the one
where the operational manager doesn’t do a good job of making sure that
the statistics are a reasonable representation of the production data.
Yes Cary, I hear what you say and agree with it. But if a significant
portion of the data is dropped overnight and then is re-created, is
the ops person then supposed to reset stats with every change in
volume in the database? Based on what criteria should (s)he act, then?
Dynamic sampling is not always the perfect solution.
The problem I'm having is with the definition of "reasonable
representation" of the production data, when such data is
highly volatile. Particularly with 9ir2...
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Cheers
Nuno Souto
in sunny Sydney, Australia
dbvision@xxxxxxxxxxxx
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