To my concern if the data is not properly processed on nodes..in such suitations this surrogate key generates holes(simply skips the ordering )ex:aa-1bb-2ba..bg...cc-3dd-4ddd-5here for ba and bg do not have seq key ,here ba and bg have holes
The main disadvantage of this stage comes when you use it second time around..There you have to give the initial value of the surrogate key....I faced the similar situation and the only way i found wa...