Re: Bitmap index costing - how to influence

From: Martin Berger <>
Date: Sat, 28 Mar 2009 21:26:21 +0100
Message-Id: <>

> There are no statistics that I can manipulate on a bitmap index that
> will affect the cost by much. In this case the index access cost is 30
> out of the entire cost of the query of 180 000.
> Bitmap indexes use mainly assumptions in regards to table access cost.

I don't think about the bit map index, but the selectivity of the query.

maybe you can provide table-stats, index-stats, column-stats (histograms, if you collect some) and the position of the column within the table.
With these informations it might be possible to adjust a test-case, even with an empty table ;-)
( And I hope the query you answered Greg was somehow representative)

I know, it's not the answer, as most of the time it's the request of more informations.
sorry for this.



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Received on Sat Mar 28 2009 - 15:26:21 CDT

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