Re: Bitmap index costing - how to influence
- From: Martin Berger <martin.a.berger@xxxxxxxxx>
- To: Christo Kutrovsky <kutrovsky.oracle@xxxxxxxxx>
- Date: Sat, 28 Mar 2009 21:26:21 +0100
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.
br
Martin
Other related posts:
