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Posted to derby-dev@db.apache.org by "Kristian Waagan (JIRA)" <ji...@apache.org> on 2011/03/07 20:47:59 UTC

[jira] Commented: (DERBY-4934) Provide automatic update and creation of index cardinality statistics (istat)

    [ https://issues.apache.org/jira/browse/DERBY-4934?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13003540#comment-13003540 ] 

Kristian Waagan commented on DERBY-4934:
----------------------------------------

The work on this feature is basically done for the 10.8 release, but there are still a few outstanding issues. I do plan to mark this issue as resolved before the RC is cut (please do so for me if I'm not around to do it :) ).
I added a bunch of links to DERBY-4939, see that issue for an overview over initial issues caused by this new feature.

> Provide automatic update and creation of index cardinality statistics (istat)
> -----------------------------------------------------------------------------
>
>                 Key: DERBY-4934
>                 URL: https://issues.apache.org/jira/browse/DERBY-4934
>             Project: Derby
>          Issue Type: Task
>          Components: SQL, Store
>    Affects Versions: 10.8.0.0
>            Reporter: Kristian Waagan
>            Assignee: Kristian Waagan
>
> Derby has been having problems with stale index cardinality statistics causing performance degradation because the optimizer picks a sub-optimal plan.
> This master JIRA issue tracks the addition of a feature that will automatically update and create index cardinality statistics.
> Note: For brevity I have decided to call the the feature istat during development :)

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