That sounds like you are dodging the actual problem. I mean you can put that same PageIsFull() check in master code as well and then you will most probably again see the same regression.
Well I don't see it that way. There was a specific concern about a specific workload that WARM might regress. I think this change addresses that. Sure if you pick that one piece, put it in master first and then compare against rest of the WARM code, you will see a regression.
BTW the PageIsFull() check may not help as much in master as it does with WARM. In master we anyways bail out early after couple of column checks. In master it may help to reduce the 10% drop that we see while updating last index column, but if we compare master and WARM with the patch applied, regression should be quite nominal.
