Re: CREATE OR REPLACE FUNCTION vs ownership

On 10/1/09 9:26 PM, "Robert Haas" <robertmhaas(at)gmail(dot)com> wrote:

2009/10/1 KaiGai Kohei <kaigai(at)ak(dot)jp(dot)nec(dot)com>:
> Robert Haas wrote:
>> On Thu, Oct 1, 2009 at 8:52 PM, Euler Taveira de Oliveira
>> <euler(at)timbira(dot)com> wrote:
>>> David E. Wheeler escreveu:
>>>> On Oct 1, 2009, at 3:42 PM, Tom Lane wrote:
>>>>
>>>>> My inclination is to think that the right behavior for REPLACE FUNCTION
>>>>> is to keep the old proowner and proacl values, because that's what it
>>>>> always has done and nobody's complained. But I suppose a case could
>>>>> be made that you're completely replacing the function and so you should
>>>>> replace its ownership/permissions too. The CREATE FUNCTION reference
>>>>> page fails to specify either way, which is a documentation bug as well.
>>>>>
>>>>> Comments?
>>>> The latter, I think. If I replace a function, I should be the new owner.
>>>> To me it makes no sense for someone else to own it.
>>>>
>>> Hmm... Using the same logic, if I add a new column should I be the table
>>> owner? If you're changing the function that is because you have permission.
>>>
>>> IMHO the owner should be preserved. In my mind, REPLACE is for changing the
>>> content and not the properties (name, owner, etc).
>
> If so, it seems to me CREATE OR REPLACE is equivalent to ALTER FUNCTION
> with currently unsupported option. In this case, it is not necessary to
> check CREATE privilege on the namespace because it does not affect to
> its name/schema.

Right - so the subtle point here is that ALTER means something
different from CREATE OR REPLACE. "ALTER" means to make a
modification to something; to change it; to adjust one particular
property of the object without disturbing the others. On the other
hand, "REPLACE" means to get rid of something and replace it with an
entirely new thing. I think that is exactly why we have ALTER TABLE
but CREATE OR REPLACE FUNCTION.

Now, if we want to have an ALTER FUNCTION that replaces the function
definition and leaves the owner intact - fine! But that is not what
REPLACE means.

By this argument CREATE OR REPLACE FUNCTION should be able to change the
return type of the function; which it can't.

>> I disagree. I think David has this one right. I expect the results
>> of CREATE OR REPLACE to be the same as the result of CREATE would have
>> been had the object not existed.
>
> If so, it seems to me CREATE OR REPLACE is equivalent to a pair of
> actions: 1) DROP FUNCTION (if exist) and 2) CREATE FUNCTION.

Except that you don't have to drop and recreate the dependencies, if any.

...Robert

And there are things that you can do with a real drop/create that you cannot
do with create/replace. In other words I agree with others that this is more
of an ALTER operation.

-Caleb