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From "Rick Hillegas (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-573) Provider support for optimizer overrides in Derby.
Date Tue, 20 Sep 2005 16:09:31 GMT
    [ http://issues.apache.org/jira/browse/DERBY-573?page=comments#action_12330018 ] 

Rick Hillegas commented on DERBY-573:
-------------------------------------

Thanks, Mamta, for pointers to these two threads. There is some discussion here about where
to put optimizer threads and how to bind them to specific queries. The consensus seems to
be to embed hints in individual queries. No argument there.

However, these threads do not address the problem of the parser silently ignoring mis-typed
optimzer directives. I think this is a brittle user api and a serious issue with the current
functional spec.

> 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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