Re: OBJECT_ATTRIBUTE is useless (or: ALTER TYPE vs ALTER TABLE for composites)

Please see check_object_ownership(). It checks relation's ownership
if OBJECT_COLUMN, however, type's ownership is the correct check if
OBJECT_ATTRIBUTE.

--
NEC OSS Promotion Center / PG-Strom Project
KaiGai Kohei <kaigai@ak.jp.nec.com>


> -----Original Message-----
> From: pgsql-hackers-owner@postgresql.org
> [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Alvaro Herrera
> Sent: Tuesday, February 24, 2015 4:02 AM
> To: Pg Hackers; Peter Eisentraut
> Subject: [HACKERS] OBJECT_ATTRIBUTE is useless (or: ALTER TYPE vs ALTER TABLE
> for composites)
> 
> I found that the OBJECT_ATTRIBUTE symbol is useless.  I can just remove
> it and replace it with OBJECT_COLUMN, and everything continues to work;
> no test fails that I can find.
> 
> I thought we had a prohibition against ALTER TABLE when used on
> composites, but it's not as severe as I thought.  The following commands
> fail in master:
> 
> ALTER TABLE comptype RENAME TO comptype2;    -- HINT: Use ALTER TYPE
> ALTER TABLE comptype SET SCHEMA sch;        -- HINT: Use ALTER TYPE
> 
> However, the following command works in master:
> 
> ALTER TABLE comptype RENAME COLUMN a TO b;
> and has the same effect as this:
> ALTER TYPE comptype RENAME ATTRIBUTE a TO b;
> 
> The RENAME ATTTRIBUTE case in RenameStmt is the only thing currently
> using OBJECT_ATTRIBUTE; therefore, since in precisely that case we do
> not prohibit using ALTER TABLE, we can just remove OBJECT_ATTRIBUTE
> completely.  That leads to the attached patch, which changes no test
> result at all.
> 
> This symbol was added in
> 
> commit e440e12c562432a2a695b8054964fb34e3bd823e
> Author: Peter Eisentraut <peter_e@gmx.net>
> Date:   Sun Sep 26 14:41:03 2010 +0300
> 
>     Add ALTER TYPE ... ADD/DROP/ALTER/RENAME ATTRIBUTE
> 
>     Like with tables, this also requires allowing the existence of
>     composite types with zero attributes.
> 
>     reviewed by KaiGai Kohei
> 
> Thoughts?
> 
> --
> Álvaro Herrera                http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services