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Message Posted: Fri, 25 Apr 2003 @ 13:02:30 GMT

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David,

I assume that by "bit mapping" you mean that the optimizer has selected a bit map set manipulation as part of its predicate evaluation plan. Having said that, let me note that disjunctive connectors (or's) will return more rows than conjunctive connectors (and's). So the or's in your example will wind up being estimated as costing more to process. This will often result in changing the optimizer's plan. The optimizer concluded that the plan it chose was "cheaper" than the BMSM that you were hoping for. If you think the optimizer chose incorrectly, you may be able to coax it by enhancing your statistics, or using other tactics (which may fail in future releases). Or you may want to open an issue with the GSC to have it look at the optimizer.

Pat Belle
Certified Master

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