Archives of the TeradataForum
Message Posted: Sun, 20 Mar 2005 @ 00:59:48 GMT
you're right, but even then, what is the chance to update 2 or more rows with the same hashrow value out of 2^32 rows at the same time?
I don't know the hashing algorithm which is used - I think, it quite a good one, but ( as a rule of thumb ) collisions start to occur mainly if more than 80% of the values are already occupied: This means at a 2^32*0.8 level, which is still more than 2^31.
So the chance for 2 rows would be 1:2^31*2^31 --> 1:2^62
I would not bet a cent on this chance ;)
|Copyright 2016 - All Rights Reserved|
|Last Modified: 28 Jun 2020|