Re: Partitioning or BitMap-Index?

From: John Russell <netnews5_at_johnrussell.mailshell.com>
Date: Thu, 13 Feb 2003 05:11:30 GMT
Message-ID: <jq9m4vgo2qsg0as5g3ea91l5qc29eu0154@4ax.com>

On 12 Feb 2003 04:17:53 -0800, cha_at_christian-hartmann.de (Christian Hartmann) wrote:
>I have 8.1.7 database and a table with a column with values of 0 and
>1.
>
>The column is used in every sql-statement against the table.
>
>For this low cardinality I wonder wheter a bitmap-index or a
>partitioning is the best way to improve the performance of this table.

I recall reading (don't have the URL handy) that if the data is evenly distributed like this across just a couple of values, like 0/1 or M/F, the bitmap index is not recommended. If you do a query on all the '0' values or all the '1' values, chances are it's going to have to read all the data blocks anyway, so going through the index hasn't really saved you any I/O.

Don't have any experience myself with partitioning. (Not yet!)

John Received on Wed Feb 12 2003 - 23:11:30 CST