Re: Bug in to_timestamp().

Robert Haas <robertmhaas@gmail.com> writes:
> On Fri, Jun 24, 2016 at 12:26 PM, Steve Crawford
> <scrawford@pinpointresearch.com> wrote:
>> To me, 2016-02-30 is an invalid date that should generate an error.

> I don't particularly disagree with that, but on the other hand, as
> mentioned earlier, to_timestamp() is here for Oracle compatibility,
> and if it doesn't do what Oracle's function does, then (1) it's not
> useful for people migrating from Oracle and (2) we're making up the
> behavior out of whole cloth.  I think things that we invent ourselves
> should reject stuff like this, but in a compatibility function we
> might want to, say, have compatibility.

Agreed, mostly, but ... how far are we prepared to go on that?  The one
thing I know about that is different from Oracle and is not something that
most people would consider clearly wrong is the behavior of the FM prefix.
We think it's a prefix that modifies only the next format code; they think
it's a toggle.  If we make that act like Oracle, we will silently break an
awful lot of applications, and there will be *no way* to write code that
is correct under both interpretations.  (And no, I do not want to hear
"let's fix it with a GUC".)  So I'm afraid we're between a rock and a hard
place on that one --- but if we let that stand, the argument that Oracle's
to_timestamp should be treated as right by definition loses a lot of air.

			regards, tom lane