Re: Bitmap Index, when use it?

From: Richard Foote <>
Date: Fri, 01 Feb 2008 12:10:00 GMT
Message-ID: <s_Doj.9833$>

"Cassiano" <> wrote in message
> Hello,
> I've a table wich 6 milions of rows, and this table have one column
> "TYPE" char(2).
> This column is used to descript the type of the row.
> This column have 35 distict values and is frequently used in "where"
> clause.
> I think this is a good column to create an Bitmap index? It's true? or
> 35 distict values is so much to bitmap indexes?
> Thanks for help.

Hi Cassiano

This Blog entry of mine might interest you:

It discusses how bitmap indexes can actually be very beneficial with many tens of thousands of distinct column values. Suggestions that Bitmap Indexes should only be used for "handfuls" of distinct columns is one of those dear little Oracle myths we all love and know so well ...


Richard Foote Received on Fri Feb 01 2008 - 06:10:00 CST

Original text of this message