@Mithical I've made another change that slightly alters the stats as I'm now counting on postid instead of the revisionguid. I expect the stats shift a bit then. On the plus side: the query can now use the only extra index on the posthistory table instead of having to scan all rows feom that table. Stack Overflow is included again.
Wonderful, thank you. I'm going to bed now, but you might want to update the Meta post as well if you've already put all the effort into fixing the query :D
