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Message Posted: Wed, 27 Mar 2002 @ 23:19:07 GMT


     
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Subj:   Re: Collect Stats on large table
 
From:   Thomas A. Fastner

Pauline,

you definitely need statistics on large tables. This will enable 'with high confidence' decisions of the optimizer and come up with the most effective access plan. In case the optimizer is missing statistics a random sample will be taken and due to the size of the table (unless the data are skewed) the optimizer will provide basically the same statistical information, but makes his decision with a lower confidence level.

If the data don't change much, like having a three year detail table and adding daily or weekly data, you should be fine for a while. In this case there is no need to refresh the statistics weekly; probably every 6 month would be enough. (The recommendation might change in V2R5 with PPI)

The note in the documentation looks to me like a left over from previous releases, when the optimizer was less sensitive and sophisticated.

Best regards,

Tom Fastner
Consultant
Teradata Certified Master
Teradata
A Division of NCR



     
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