Bruce Momjian <pgman@candle.pha.pa.us> writes:
> I think we should return intervals only when we can't return meaningful
> timestamp values. I don't have any logic to back up that opinion, though.
It's easy: a value measured as an interval will be obsolete by the time
it's delivered to the client. A start timestamp is actually meaningful
information that will still be correct when used; uptime is fragile.
regards, tom lane