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From "Kristian Waagan (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-5684) Explore possible istat daemon improvements and optimizations
Date Fri, 18 May 2012 13:12:06 GMT

    [ https://issues.apache.org/jira/browse/DERBY-5684?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13278792#comment-13278792
] 

Kristian Waagan commented on DERBY-5684:
----------------------------------------

I have decided to pull the plug on the possible optimization for foreign key indexes. I don't
understand it well enough, and it is hard to verify what it actually does wrt the choices
taken by the optimizer.
With that decision, the following pieces remain:
 a) Drop disposable statistics entries. I will post the patch under DERBY-5680.
 b) Skip statistics for single-column primary keys. I will post the patch under DERBY-3790
after (a) is done.
 c) Move invalidation when updating statistics. Committed as DERBY-5770.
                
> Explore possible istat daemon improvements and optimizations
> ------------------------------------------------------------
>
>                 Key: DERBY-5684
>                 URL: https://issues.apache.org/jira/browse/DERBY-5684
>             Project: Derby
>          Issue Type: Task
>            Reporter: Kristian Waagan
>         Attachments: derby-istat-exploration-1.diff, derby-istat-exploration-2.diff,
derby-istat-exploration-3.diff, derby-istat-exploration.diff
>
>
> A task tracking some experiments on the istat daemon and the statistics update code.

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