In an ideal situation, agreed. But surely that depends entirely on how many tables are being queried (how many tables already exist in the cache), the size of t

In an ideal situation, agreed. But surely that depends entirely on how many tables are being queried (how many tables already exist in the cache), the size of the rows, how much RAM the host has / how big the cache is, plus a few other variables most probably. What I mean is: like all other things, it depends. And with assumptions like this, it is generally better to measure.