Different error messages executing CREATE TABLE or ALTER TABLE to create a column "xmin"

Hi hackers,

the attached patch fixes the problem I explained in pgsql-bugs (forwarded).
It's a trivial problem, so no initial patch design was required.

Hope to see my patch applied.
Thanks for your work.

Regards.

---------- Forwarded message ----------
From: Giuseppe Sucameli <brush(dot)tyler(at)gmail(dot)com>
Date: Sun, Jan 22, 2012 at 2:22 PM
Subject: Different error messages executing CREATE TABLE or ALTER
TABLE to create a column "xmin"
To: pgsql-bugs(at)postgresql(dot)org

Hi all,

trying to create a table with a column xmin I get the
following error message:

test=> create table lx (xmin int);
ERROR:  column name "xmin" conflicts with a system
column name

Instead I get a different (and less understandable) error
message if I try to add a column named xmin to an
existent table:

test=> create table lx (i int);
CREATE TABLE
test=> alter table lx add xmin int;
ERROR:  column "xmin" of relation "lx" already exists.

The same problem occurs using "xmax" as column name.

I'm on Ubuntu 11.04.
Tried on both PostgreSQL 8.4.10 and 9.1.2

Regards.

--
Giuseppe Sucameli

--
Giuseppe Sucameli