From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Steve Crawford <scrawford@pinpointresearch.com>,
        Alex Ignatov <a.ignatov@postgrespro.ru>,
        Albe Laurenz <laurenz.albe@wien.gv.at>,
        amul sul <sul_amul@yahoo.co.in>,
        PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Bug in to_timestamp().
In-reply-to: 
 <CA+Tgmoa65k+PQNNAu717DdjaA9-uGMWt=ov0NUWmUXggZRRY3A@mail.gmail.com>
References: 
 <1873520224.1784572.1465833145330.JavaMail.yahoo.ref@mail.yahoo.com>
 <1873520224.1784572.1465833145330.JavaMail.yahoo@mail.yahoo.com>
 <20932.1465834344@sss.pgh.pa.us>
 <CA+TgmoaD8TuS=sHKS1f1qAfizCBouejgmO2jYnJ_=ia343uGSA@mail.gmail.com>
 <CA+TgmoZKJOoywaBT-K_pmQT4yPuDmR5AxjcEdwiCofA5Q3S0yA@mail.gmail.com>
 <11349.1466429771@sss.pgh.pa.us>
 <A737B7A37273E048B164557ADEF4A58B53862B37@ntex2010i.host.magwien.gv.at>
 <a0c79f21-1d30-23d2-b82d-33031503c6dd@postgrespro.ru>
 <CAEfWYywsvT1_PV7pFJhJZJ03R3DmgqgDaCjHpXJdCHSfCMY6fw@mail.gmail.com>
 <CA+Tgmoa65k+PQNNAu717DdjaA9-uGMWt=ov0NUWmUXggZRRY3A@mail.gmail.com>
Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Fri, 24 Jun 2016 16:33:59 -0400"
Date: Fri, 24 Jun 2016 17:16:38 -0400
Message-ID: <845.1466802998@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

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


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers