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From "Satheesh Bandaram (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-573) Provider support for optimizer overrides in Derby.
Date Tue, 20 Sep 2005 16:35:31 GMT
    [ http://issues.apache.org/jira/browse/DERBY-573?page=comments#action_12330020 ] 

Satheesh Bandaram commented on DERBY-573:
-----------------------------------------

It should be possible to enhance current Derby RunTimeStatistics mechanism to display user
specified optimizer directives being used if specified. Since optimizer directives are typically
used by application developer, not the end users, it should be easy for them to confirm the
directives are taking effect. Derby provides several ways to get execution plans... including
RunTimeStatistics or derby.language.logQueryPlan. These mechanisms can specify when optimizer
directives are being used.


> Provider support for optimizer overrides in Derby.
> --------------------------------------------------
>
>          Key: DERBY-573
>          URL: http://issues.apache.org/jira/browse/DERBY-573
>      Project: Derby
>         Type: New Feature
>   Components: SQL
>     Versions: 10.2.0.0
>     Reporter: Mamta A. Satoor
>     Assignee: Mamta A. Satoor
>  Attachments: optimizeroverrides.html
>
> Derby's query optimizer usually makes the best choice of join order and access path.
The default join strategy ususally works the best too. However, there are some cases in which
user may want to override the optimizer or the default values. Providing support for optimizer
overrides will allow users to hand-tune the optimizer for queries. 

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