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Message Posted: Mon, 18 Aug 2008 @ 20:42:16 GMT


     
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Subj:   Column Order in Primary Index
 
From:   Goli, Srikanth

Hi -

Does the order of columns in a primary index have any impact on the hashing algorithm? My understanding is that hashing algorithm is insensitive to the order of columns in the index, and would always return the same AMP # regardless of the order of columns. Even if it were to make difference, does it make sense to order your columns in such a way that you get better distribution, like ordering columns with wider range of values to the right and columns with fewer values to the left? Is this something that Teradata commits to maintain, what if the algorithm to hashing were to change?

Thanks for your input from the members.



     
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