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From "Knut Anders Hatlen (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-4116) SYSCS_UTIL.SYSCS_UPDATE_STATISTICS should update the store estimated row count for the table
Date Wed, 25 Mar 2009 10:22:52 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12689068#action_12689068
] 

Knut Anders Hatlen commented on DERBY-4116:
-------------------------------------------

I guess it's only implemented for heap conglomerates because the row count should really be
the same in the base table and all its indexes, and there's no need to store the estimated
row count for a table more than one place. The optimizer will probably always look for the
estimate in the heap conglomerate, so it doesn't notice the estimate in the index.

Does it work as expected if you do something like this near the end of the method?

        ScanController heapSC = tc.openScan(td.getHeapConglomerateId(), ...);
        heapSC.setEstimatedRowCount(rowCount);
        heapSC.close();

> SYSCS_UTIL.SYSCS_UPDATE_STATISTICS should update the store estimated row count for the
table
> --------------------------------------------------------------------------------------------
>
>                 Key: DERBY-4116
>                 URL: https://issues.apache.org/jira/browse/DERBY-4116
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 10.5.1.0, 10.6.0.0
>            Reporter: Kathey Marsden
>
> When SYSCS_UTIL.SYSCS_UPDATE_STATISTICS is run, it doesn't update the store estimated
row count.  The program oldSelectivity.java attached to DERBY-3955 shows that the statistics
are not updated.
> See discussions in DERBY-3955
> https://issues.apache.org/jira/browse/DERBY-3955?focusedCommentId=12688789&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12688789
> https://issues.apache.org/jira/browse/DERBY-3955?focusedCommentId=12688813&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12688813

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