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.
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.