> we bite the bullet to the extent of supporting a distinction between
> physical and logical column numbers, then ISTM there's no strong need
> to do any of this other stuff at all. I'd expect that an inserted or
> updated tuple would have a NULL in any physical column position that
> doesn't have an equivalent logical column, so the space cost
> is minimal
> (zero, in fact, if there are any other NULLs in the tuple). Over time
> the space occupied by deleted-column data would gradually go away as
> tuples got updated.
This said, I think Hiroshi's patch seems a perfect starting point, no ?
Andreas