rp0428 wrote:USED in DW is fine.. I am not arguing that..
BITMAP indexes are created and are most appropriate for columns having low distinct values.
That MYTH has been busted for many years now by many people.
See Richard Foote's series of articles about this myth and many others regarding indexes.
One of the great myths in Oracle is that bitmap indexes are only suitable and should only be used with columns that have so-called low cardinality (few distinct) values
. . .
The next time you unfortunately read that bitmap indexes should only be used with very “few” distinct values and would be “huge” otherwise, well hopefully you’ll appreciate that’s simply not correct.
Thanks for sharing!!!
A gender column, which has only two distinct values (male and female), is optimal for a bitmap index. However, data warehouse administrators also build bitmap indexes on columns with higher cardinalities.
34MCA2K2 wrote:Sorry for the late response. rp0428's post is clear enough for you to understand the issue.
I am sorry for being ignorant, can you please cite any scenario of locking due to bitmap indices? A link can be useful as well.