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From "Mike Matrigali (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-269) Provide some way to update index cardinality statistics (e.g. reimplement update statistics)
Date Fri, 27 Jun 2008 15:58:45 GMT

     [ https://issues.apache.org/jira/browse/DERBY-269?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Mike Matrigali updated DERBY-269:
---------------------------------


I am ok with following the existing paradigm that other procedures use to implement this,
ie. call the parser on new internal
syntax.  But I wonder if anyone knows how easy it might be to instead call directly whatever
the parser generates in this case.
I don't know if it really matters, and maybe the current way is best with more code sharing.
 I definitely thinks it makes sense
for the bulk of the code to go into alter table execution where it can share all the existing
code for the same type of work.

> 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
>
> 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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