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From Oyvind.Bakk...@Sun.COM
Subject Re: derby performance and 'order by'
Date Fri, 23 Sep 2005 07:35:02 GMT
Rick Hillegas wrote:
> Thanks for the pointer to this presentation, Oyvind. It's a pretty 
> startling observation though I'm not sure how to use it. I'd be 
> interested in hearing your thoughts about this some time.

The question raised in this presentation is whether the optimizers in 
the databases examined (Oracle, DB2 and SQL Server) are actually too 
clever, evaluating (in some cases) 100+ query plans for a single query 
when simply changing the selectivity on two relations. The assumption is 
that they could evaluate far less plans and still perform well.

Now, in Derby, I think we're still on the opposite side - we should 
probably investigate more optimization techniques and execution plans, 
as this thread has shown.

Oyvind Bakksjo
Sun Microsystems, Database Technology Group
Trondheim, Norway

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