Date: Tue, 30 Sep 2003 11:10:30 -0700 (PDT)
From: Stephan Szabo <sszabo@megazone.bigpanda.com>
To: Jan Wieck <JanWieck@Yahoo.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Bruce Momjian <pgman@candle.pha.pa.us>,
	Christopher Kings-Lynne <chriskl@familyhealth.com.au>,
	Peter Childs <Blue.Dragon@blueyonder.co.uk>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: ADD FOREIGN KEY (was Re: [GENERAL] 7.4Beta)
In-Reply-To: <3F79BD24.3090400@Yahoo.com>
Message-ID: <20030930110434.R18474@megazone.bigpanda.com>
References: <200309301233.h8UCXcQ21796@candle.pha.pa.us>
	<19140.1064930871@sss.pgh.pa.us>
	<20030930074408.H14474@megazone.bigpanda.com>
	<3F79BD24.3090400@Yahoo.com>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

On Tue, 30 Sep 2003, Jan Wieck wrote:

> Stephan Szabo wrote:
> > On Tue, 30 Sep 2003, Tom Lane wrote:
> >
> >> I see where Stephan is coming from, but in my mind disabling consistency
> >> checks ought to be a feature reserved to the DBA (ie superuser), who
> >> presumably has some clue about the tradeoffs involved.  I don't think
> >> ordinary users should be able to do it.  If we can get the cost of
> >> performing the initial check down to something reasonable (and I don't
> >> mean "near zero", I mean something that's small in comparison to the
> >> other costs of loading data and creating indexes), then I think we've
> >> done as much as we should do for ordinary users.
> >
> > Limiting the cases under which constraint ignoring works is certainly
> > fine by me, but I was assuming that we were trying to make it accessable
> > to any restore. If that's not true, then we don't need to worry about that
> > part of the issue.
>
> It is not true.
>
> Fact is that restoring can require more rights than creating the dump.
> That is already the case if you want to restore anything that contains
> objects owned by different users. Trying to enable everyone who can take
> a dump also to restore it, by whatever mechanism, gives someone the
> right to revert things in time and create a situation (consistent or
> not) that he could not (re)create without doing dump/restore. This is
> wrong and should not be possible.

I think this is a larger argument than the one that was being discussed
above. Given a dump of objects I own, can I restore them without requiring
the fk check to be done if I alter table add constraint a foreign key? If
the answer to that is no, then the option can be put in as a superuser
only option and it's relatively easy. If the answer to that is yes, then
there are additional issues that need to be resolved.