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From "Knut Anders Hatlen (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-4121) Documentation: more UPDATE_STATISTICS fixes needed for Reference Manual and Tuning Derby
Date Fri, 03 Apr 2009 11:12:13 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4121?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12695332#action_12695332

Knut Anders Hatlen commented on DERBY-4121:

To Mike's question, I think that (2) will be a better guess in more cases than (1). Of course,
if you have a limited number of possible/likely values, the average number of duplicates will
increase as the number of rows increases, but as long as there's a relatively high number
of possible values (2) is more likely to hold. For columns like gender, city and state, I'd
assume that (1) in many cases is a much better guess than (2), though.

> Documentation: more UPDATE_STATISTICS fixes needed for Reference Manual and Tuning Derby
> ----------------------------------------------------------------------------------------
>                 Key: DERBY-4121
>                 URL: https://issues.apache.org/jira/browse/DERBY-4121
>             Project: Derby
>          Issue Type: Bug
>          Components: Documentation
>    Affects Versions:
>            Reporter: Kim Haase
>            Priority: Minor
> Kathey Marsden comments on DERBY-3787:
> Not a show stopper for the release, but in beginning my buddy testing,
>  I noticed the examples should use CALL e.g.
> Also in the Tuning Guide under Working with Cardinality Statistics -> When Cardinality
Statistics Go Stale we should refer users to the SYSCS_UTIL.SYSCS_UPDATE_STATISTICS stored
procedure to update their statistics and cross reference the reference guide.
> Myrna van Lunteren suggests a new issue for this, so I'm filing it.

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