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 http://weblogs.java.net/blog/bakksjo/
