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From "Mamta A. Satoor (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-269) Provide some way to update index cardinality statistics (e.g. reimplement update statistics)
Date Tue, 24 Jun 2008 17:46:45 GMT

    [ https://issues.apache.org/jira/browse/DERBY-269?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12607698#action_12607698
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Mamta A. Satoor commented on DERBY-269:
---------------------------------------

I will look at adding some sort of system procedure which can be invoked by the user manually
to fix the statistics. Later on, we should look into providing a zero admin solution which
should be able to share some of the code provided by the new system procedure.

> Provide some way to update index cardinality statistics (e.g. reimplement update statistics)
> --------------------------------------------------------------------------------------------
>
>                 Key: DERBY-269
>                 URL: https://issues.apache.org/jira/browse/DERBY-269
>             Project: Derby
>          Issue Type: New Feature
>          Components: SQL
>    Affects Versions: 10.0.2.0, 10.0.2.1, 10.1.1.0, 10.2.2.0, 10.3.1.4
>            Reporter: Stan Bradbury
>            Assignee: Mamta A. Satoor
>
> Performance problems are being reported that can be resolved by updating the cardinality
statistics used by the optimizer.  Currently the only time the statistics are guaranteed to
be an up-to-date is when the index is first created on a fully populated table.  This is most
easily accomplished on an existing table by using the command: 
>    alter table <table-name> compress [sequential]  
> Compress table is an I/O intensive task.  A better way to achieve this would be to re-enable
parser support for the 'update statistics' command or re-implement the update in some other
fashion.

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