Re: BITMAP Versus B-TREE

One other thought to throw into the conversation -- have you considered the possibility of using a function based index? Set up right they can be a great option with significant space savings and non of the DML issues bit mapped indexes have. Function based indexes work well if you are querying, and therefore indexing, on only one of the values, either YES or NO, or if there are a lot of NULLs in the column.

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Well, These indexes do exist already. For example, there is a column called FLAG with values of 'YES' or 'NO' and there are 6 Millions of rows in the index... but distinct values are only two ('YES' and 'NO')... Im just thinking to convert this to Bitmap...
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Rumpi Gravenstein

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