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Posted to derby-dev@db.apache.org by "Kathey Marsden (JIRA)" <ji...@apache.org> on 2009/03/25 00:45:50 UTC
[jira] Commented: (DERBY-4116) SYSCS_UTIL.SYSCS_UPDATE_STATISTICS
should update the store estimated row count for the table
[ 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 757498)
+++ 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
finally
{
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 wrong?
> 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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