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Message Posted: Wed, 06 Mar 2002 @ 11:53:14 GMT
| Subj: | | Re: What information does 'collect statistics' store? |
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| From: | | David Wellman |
The result of the COLLECT STATISTICS command is a number of 'buckets' (I think @100) of information. For each 'bucket' the information
stored is maximum value, mode value (i.e. most frequently occurring), how many rows contain this mode frequency, number of distinct non-
modal values and number of rows which contain a non-modal value. This information all comes from 3Q 2001 Teradata Magazine.
As much as it 'would be nice' to store the number of rows for each value that is not practical where you have potentially millions of
distinct values for a column.
Cheers,
Dave
Ward Analytics Ltd: Information in motion (www.ward-analytics.com)
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