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From "Kathey Marsden (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 Tue, 24 Mar 2009 23:45:50 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12688935#action_12688935

Kathey Marsden commented on DERBY-4116:

Well just to see if this was a really easy fix, so I could continue my testing, I tried the
trivial patch below:

--- java/engine/org/apache/derby/impl/sql/execute/AlterTableConstantAction.java (revision
+++ java/engine/org/apache/derby/impl/sql/execute/AlterTableConstantAction.java (working copy)
@@ -744,6 +744,7 @@
                                        rowBufferArray[GROUP_FETCH_SIZE - 1] = lastUniqueKey;
                                        lastUniqueKey = tmp;
                                } // while
+                               gsc.setEstimatedRowCount(numRows);
                        } // try

but it doesn't affect my test case.  I verified that with this change the code goes through
OpenBTree.setEstimatedRowCount and sets the count to 4000, but there is this comment in OpenBTree.setEstimatedRowCount():

     * This call is currently only supported on Heap conglomerates, it
     * will throw an exception if called on btree conglomerates.
It doesn't throw an exception, but it doesn't seem to do too much either. Any ideas what's

> SYSCS_UTIL.SYSCS_UPDATE_STATISTICS should update the store estimated row count for the
> --------------------------------------------------------------------------------------------
>                 Key: DERBY-4116
>                 URL: https://issues.apache.org/jira/browse/DERBY-4116
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions:,
>            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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