Tomasz Myrta <jasiek@klaster.net> writes:
> Standard Postgresql aggregate functions don't need sorted data, but my
> function needs. Look at the data:
> <value> <sum>
> 3 3
> -2 1
> 6 7 *** max_sum=7
> -3 4
> 2 6
But if the input data is sorted into increasing order, then the largest
running sum value is always at the end. Therefore max(sum()) is
equivalent to sum(); therefore you do not need the special aggregate,
nor the ordering.
regards, tom lane