On Feb 18, 2007, at 23:12 , Karsten Hilbert wrote:
On Sun, Feb 18, 2007 at 09:19:43PM +0900, Michael Glaesemann wrote:
What I don't understand, however, is exactly *why* date_trunc is
not immutable ?
I believe it's because the result of date_trunc depends on the time
zone setting for the session.
...
So, given the same arguments, ('day', and current_timestamp),
date_trunc is returning two different results. (Casting to date has
the same issue.)
Ah, I see. That makes sense.
Now, if I'd write a
date_trunc_utc(precision, timestamp with time zone)
which converts input timestamps to UTC I could fairly safely
mark that IMMUTABLE, no ?
Yeah, I think if you normalized it to UTC you could mark your new
function as immutable.
Michael Glaesemann
grzm seespotcode net
