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Message Posted: Thu, 08 Jan 2004 @ 16:20:08 GMT


     
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Subj:   Re: How to know how the hashing algorithm works
 
From:   Dieter Noeth

John Adams wrote:

  I've gotten curious about the hashing algorithm, but there's not a lot in the documentation about how it works. I'm not interested in the proprietary details of how a value is hashed, but I am curious about how multi-field index values are determined from the values of the individual fields.  


  Any guidance on this out there?  



According to the Physical Implementation training: The hashing algorithm uses multiplication and addition as commutative operators for handling a multi-column index.

PI(A, B) = PI(B, A)

Hash (A) * Hash (B) + Hash (A) + Hash (B) =
Hash (B) * Hash (A) + Hash (B) + Hash (A)


Dieter



     
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