| I refuted what he said by pointing out that 1E9 x 1E6 = 1E15. A billion row table denormalised with a million row table = 1000 trillion row table. How big's your disk array? How are you going to ensure correctness on update? His was stupid advice and had it should not have been given. > You continue to just say it depends without giving any actual scenarios it depends. Use your common sense and then use a stopwatch, is a good start. There are entire shelves of books on this, I won't repeat them. > You make it sound like magic, but it’s not: absolutely true! > “under x and y, do z except when u” is better than it's a multidimensional problems inc. memory size, disk size, the optimiser, sizes of particular tables joined, where the hotspot is, cost of updates of non-normalised tables, etc. I can't give general advice from here. > Also, your main points are against denormalization and avoiding large table joins which are 100% rational arguments under certain workloads. I said "Denormalising is a useful tool that IME rarely gains you more than it loses you," I don't accept your criticism. |