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Re: Shrinking an index??

From: Martin Smith <mfmsith_at_erols.com>
Date: 1997/04/01
Message-ID: <3341E7CB.1E4A@erols.com>#1/1

The docs say where there's a 1,000:1 ratio of rows to distinct values. So for a million-row table, "low" cardinality would be anything under 10,000 values. We have an application with about 10 keys (dimensions); ALL BUT ONE of these it bit-mapped. Works like wildfire and saves mucho storage. Plus you don't have to pre-select the index combinations you will use. Seems like a huge win, except for some minor problems like that MS Access can't link to a table that has BMI's defined. (But you can put the indexes on after the link is made.)

>
> For which rate of low cardinality do you think that is useful
> to use bitmap indexes?
>
>
>
>
> Regards,
> --
> Luis Santos
> Relacional Consultoria
> Rio de Janeiro - Brazil
Received on Tue Apr 01 1997 - 00:00:00 CST

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