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https://issues.apache.org/jira/browse/DERBY-269?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12613587#action_12613587
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Knut Anders Hatlen commented on DERBY-269:
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I've only had a brief look at the patch, so I haven't studied the details, but
the general approach looks fine to me. Some questions/comments:
- since the code is copied from UpdateStatisticsConstantAction, I assume USCA
will be removed from the repository in a later patch?
- UpdateStatisticsConstantAction uses a strange mix of tabs and spaces for
indentation. It would be great if the indentation is cleaned up when the code
is moved.
- SystemProcedures.SYSCS_UPDATE_STATISTICS() uses tabs/spaces inconsistently
- comment in upgradeTests/_Suite.java has the wrong version number:
+ {10, 4, 1, 3}, // 10.3.1.4 (April 24, 2008 / SVN 648739)
- SYSCS_UPDATE_STATISTICS is added to Changes10_2. Shouldn't that file only
test procedures that were added in Derby 10.2?
> Provide some way to update index cardinality statistics (e.g. reimplement
> update statistics)
> --------------------------------------------------------------------------------------------
>
> Key: DERBY-269
> URL: https://issues.apache.org/jira/browse/DERBY-269
> Project: Derby
> Issue Type: New Feature
> Components: SQL
> Affects Versions: 10.0.2.0, 10.0.2.1, 10.1.1.0, 10.2.2.0, 10.3.1.4
> Reporter: Stan Bradbury
> Assignee: Mamta A. Satoor
> Attachments: DERBY269_update_statistics_svndiff_ver1.txt,
> DERBY269_update_statistics_svnstat_ver1.txt
>
>
> Performance problems are being reported that can be resolved by updating the
> cardinality statistics used by the optimizer. Currently the only time the
> statistics are guaranteed to be an up-to-date is when the index is first
> created on a fully populated table. This is most easily accomplished on an
> existing table by using the command:
> alter table <table-name> compress [sequential]
> Compress table is an I/O intensive task. A better way to achieve this would
> be to re-enable parser support for the 'update statistics' command or
> re-implement the update in some other fashion.
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