"Karl O. Pinc" <kop(at)meme(dot)com> writes:
> Incrementing the loop counter by a factor of 10, from 1000 to 10000
> makes the process take more than 100 times longer. (I only saw
> this happen when I happened upon using a numeric() datatype
> and then dividing i/100 to avoid overflow. It does not happen
> without the array and working with other, much larger, arrays
> of other data types you see no slowdown.)
It's the array access, not the arithmetic, that's getting you.
Since numeric is not a fixed-width datatype, accessing the N'th
element of the array requires O(N) time to find that element.
regards, tom lane