Re: [BUG?] strange behavior in ALTER TABLE ... RENAME TO on inherited columns

On Sun, Jan 3, 2010 at 11:18 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> 2010/1/3 KaiGai Kohei <kaigai(at)ak(dot)jp(dot)nec(dot)com>:
>>>  if (number_of_attribute_origin(myrelid, oldattname) > 1)
>>>      ereport(ERROR, ...);
>>>
>>> Am I missing something?
>
>> That sounds about right to me,
>
> It looks remarkably inefficient to me.  Do you propose to search the
> entire database's inheritance tree to derive that number?  And do it
> over again at each child table?  The method I suggested would allow the
> necessary information to be extracted during the initial search for
> child tables, which we have to do anyway.

I haven't read the code in enough detail to have an educated opinion
about whether that would induce enough overhead to be worth worrying
about it, so I will refrain from comment on this until I have done my
homework.

...Robert