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Message Posted: Thu, 17 Mar 2005 @ 12:10:10 GMT

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Subj:   Re: TPump Update
From:   keith.hammond


My understanding is that 2 different UPI values can have the same row hash. On the assumption that the HashRow function is the 'value' that would be locked, it is possible for a single column UPI to have 2 values with the same row hash. For example:

     Select Hashrow(5697436052);


     Select Hashrow(1402468761);

Both give the value: 53005335

Therefore if I locked the row with UPI = 5697436052 with a row hash lock, it would also lock the row with a UPI = 1402468761.

I think this is supported by Bills observations that the larger the Pack factor and/or the larger the number of sessions, the more blocking.



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