From: Tom Lane <tgl@sss.pgh.pa.us>
To: Stephen Frost <sfrost@snowman.net>
cc: "imai.yoshikazu@fujitsu.com" <imai.yoshikazu@fujitsu.com>,
        Euler Taveira <euler@timbira.com.br>,
        Andrew Gierth <andrew@tao11.riddles.org.uk>,
        Justin Pryzby <pryzby@telsasoft.com>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: v12 and pg_restore -f-
In-reply-to: <20191016172148.GH6962@tamriel.snowman.net>
References: <20191006190839.GE18030@telsasoft.com>
 <28770.1570394593@sss.pgh.pa.us> <875zl11tla.fsf@news-spur.riddles.org.uk>
 <30069.1570396524@sss.pgh.pa.us> <20191008180840.GQ6962@tamriel.snowman.net>
 <CAHE3wgi=VU0G9=S60=gQH+yyk8-Ke99dkt8Dp4OpZXkSu=67fQ@mail.gmail.com>
 <20191009124505.GT6962@tamriel.snowman.net>
 <OSBPR01MB4616298336E32F8EAEDA0FF394920@OSBPR01MB4616.jpnprd01.prod.outlook.com>
 <20191016172148.GH6962@tamriel.snowman.net>
Comments: In-reply-to Stephen Frost <sfrost@snowman.net>
	message dated "Wed, 16 Oct 2019 13:21:48 -0400"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <19890.1571307850.1@sss.pgh.pa.us>
Date: Thu, 17 Oct 2019 12:24:10 +0200
Message-ID: <19891.1571307850@sss.pgh.pa.us>
Precedence: bulk

Stephen Frost <sfrost@snowman.net> writes:
> First, I'd like to clarify what I believe Tom's suggestion is, and then
> talk through that, as his vote sways this topic pretty heavily.

> Tom, I take it your suggestion is to have '-f -' be accepted to mean
> 'goes to stdout' in all branches?

Yes.

> That goes against the argument that
> we don't want to break existing scripts, as it's possible that there are
> existing scripts that depend on '-f -' actually going to a './-' file.

While that's theoretically possible, I think that the number of cases
where somebody is actually expecting that is epsilon.  It seems more
useful to tell people that they can now use "-f -" in all branches,
and it's required to use it as of v12.

Alternatively, we could revoke the requirement to use "-f -" in 12,
and wait a couple releases before enforcing it.  The fundamental
problem here is that we tried to go from "-f - doesn't work" to
"you must use -f -" with no grace period where "-f - is optional".
In hindsight that was a bad idea.

> If you meant for all branches to accept '-f -' and have it go to a './-'
> file then that's just a revert of this entire change, which I can't
> agree with either

No, I'm not proposing a full revert.  But there's certainly room to
consider reverting the part that says you *must* write "-f -" to get
output to stdout.

			regards, tom lane