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Message Posted: Tue, 13 Jun 2000 @ 16:19:44 GMT


     
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Subj:   Re: Value Ordered Index
 
From:   Michael Larkins

Hi Sam:

I think that you will find the no additional space is required for a Value Order NUSI vs an regular NUSI. In some cases, it will actually be less, due to the fact that Value Ordered NUSI must be on a number value, up to 4 bytes vs a longer character column. Therefore, DATE is the most commonly used data type. Remember that the actual data value is stored as part of the NUSI structure.

If you think about it, it makes the most sense. A lot of time, a date range is what is needed (ie. week-week, month-month, etc) Like all NUSIs, you must collect statistics or the optimizer will probably ignore them. Plus, if the value is "weakly selective'" the optimize will chose a FTS even with statistics.

This isn't a very specific answer to your question, just a couple of things to think about when considering space and access requirements.

Have a great day,

Michael Larkins



     
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