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From "Bryan Pendleton (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-3259) Tuning manual needs performance tip on compressing tables
Date Sat, 09 Jan 2010 15:48:54 GMT

    [ https://issues.apache.org/jira/browse/DERBY-3259?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12798368#action_12798368
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Bryan Pendleton commented on DERBY-3259:
----------------------------------------

The email thread mentioned in the description contains lots of good information that
I can edit into the new doc topic.

It seems like we also need a few notes regarding SYSCS_UPDATE_STATISTICS, and
possibly also note that, negatively, SYSCS_INPLACE_COMPRESS_TABLE does *not*
update the statistics. See DERBY-4289, DERBY-4121, and DERBY-1964 for related thoughts.

I'll take a stab at creating a new "Ensure statistics are accurate" topic for the Performance
Tips
section of the Tuning guide, and post the results when I've got something ready to read. 

> Tuning manual needs performance tip on compressing tables
> ---------------------------------------------------------
>
>                 Key: DERBY-3259
>                 URL: https://issues.apache.org/jira/browse/DERBY-3259
>             Project: Derby
>          Issue Type: Improvement
>          Components: Documentation
>    Affects Versions: 10.3.1.4
>            Reporter: Kim Haase
>            Assignee: Bryan Pendleton
>
> The "Performance Tips and Tricks" section of the Tuning Derby manual needs a topic that
recommends the use of the SYSCS_UTIL.SYSCS_COMPRESS_TABLE procedure to resolve performance
problems having to do with indexes and complex table joins. (Please rephrase this if I haven't
put it correctly.)
> For details, see the discussion at http://www.nabble.com/Re%3A-FW%3A-Advice-on-*very*-badly-performing-query-tf4939807.html.

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