Vincenzo Romano <vincenzo(dot)romano(at)gmail(dot)com> writes:
> It sounds quite strange to me that numeric is faster than bigint.
This test is 100% faulty, because it fails to consider the fact that the
accumulator used by sum() isn't necessarily the same type as the input
data. In fact we sum ints in a bigint and bigints in a numeric to avoid
overflow.
If you try it with max() you'd likely get less-surprising answers.
regards, tom lane