Re: tablecmds.c/MergeAttributes() cleanup

Robert Haas <robertmhaas@gmail.com> writes:
> On Fri, Jan 12, 2024 at 5:32 AM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
>> In addition, it also occurs to me now that maybe it would make sense to
>> change the TupleDesc implementation to use a List of Form_pg_attribute
>> instead of an array, and do away with ->natts.  This would let us change
>> all "for ( ... natts ...)" loops into foreach_ptr() loops ...  there are
>> only five hundred of them or so --rolls eyes--.

> Open-coding stuff like this can easily work out to a loss, and I
> personally think we're overly dependent on List. It's not a
> particularly good abstraction, IMHO, and if we do a lot of work to
> start using it everywhere because a list is really an array, then what
> happens when somebody decides that a list really ought to be a
> skip-list, or a hash table, or some other crazy thing?

Without getting into opinions on whether List is a good abstraction,
I'm -1 on this idea.  It would be a large amount of code churn, with
attendant back-patching pain, and I just don't see that there is
much to be gained.

            regards, tom lane