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Message Posted: Wed, 26 Apr 2006 @ 20:27:58 GMT


     
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Subj:   Re: How good is Explain on a SQL ?
 
From:   Christian Schiefer, makeITdone

Hi,

Ad 1.) Confidence: This depends on the "statistics" collected on the columns you are joining.

Ad 2.) As far as I know in the recent ( Releases V2R6 ), the estimated time is calculated under the assumption, that this query is getting all resources ( running alone ) on the system. I remember earlier releases, where the estimated times differed depending on the workload of the system at the time the explain ran.


Hope this helps

Christian

makeITdone IT Services
Vienna
Austria



     
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