To: Gregory Stark <stark@enterprisedb.com>
cc: pgsql-hackers@postgresql.org
Subject: Re: Should creating a new base type require superuser status? 
In-reply-to: <87od4fghgd.fsf@oxford.xeocode.com> 
References: <19715.1217447413@sss.pgh.pa.us>
	<87sktrgjdj.fsf@oxford.xeocode.com>
	<23742.1217453388@sss.pgh.pa.us>
	<87od4fghgd.fsf@oxford.xeocode.com>
Comments: In-reply-to Gregory Stark <stark@enterprisedb.com>
	message dated "Wed, 30 Jul 2008 23:01:06 +0100"
Date: Wed, 30 Jul 2008 18:13:10 -0400
Message-ID: <24287.1217455990@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Gregory Stark <stark@enterprisedb.com> writes:
> "Tom Lane" <tgl@sss.pgh.pa.us> writes:
>> Unless you're going to allow them to create new C functions, I'm not
>> clear on how much they're going to be able to change the semantics.

> Well there's plenty that can be done just using text or bytea as
> representations. citext, or uuid for example.

For the sort of look-ma-no-C programming that you seem to be
envisioning, I don't think that real base types are appropriate at all.
What might make sense is to handle it as a domain over some
suitably-generic base type.  The thing we'd have to fix to make that
work is the way that the ambiguous-function resolution rules
discriminate against functions that're declared to take domains.
Which is hard, but it seems a lot less likely to lead to weird
security risks than letting untrusted users mess with the details
of base-type operations.

Elein was going to go off in a corner and think about how to make that
work better, but I dunno if she's gotten anywhere yet.

			regards, tom lane