@rene So, I did a bit of
tinkering. The problem wasn't the post body scan, it was the inner join of p to q including coalesce (I think coalesce causes it to not use the index perhaps?). I modded it a bit so P is just answers and Q is just questions, and now it's quite fast. (I'm okay with ignoring questions with the text for the moment, as I was looking for a dup that included the values just in the answer)