I don't think this is cheating.. if someone asks me how to design a distributed join and I answer because I worked on distributed joins directly, is that cheating?

This reminds me of a guy who, on the contrary, probably thinks I wronged him during an interview. He couldn't solve my relatively simple programming question and then remarked, sounding rather unhappy, that this question "wasn't on leetcode", and so he wasn't prepared for it ;)