> Given the 8.0 ALTER TABLE feature of being able to rewrite the whole
> table, one could now think about doing it without decoupling logical
> and physical numbers: just rewrite the table with the new column
> inserted in the proper place. This moves the problem to a different
> area, which is being sure you have updated every place in the system
> catalogs and backend caches that references the old column numbers of
> the renumbered columns. Again, doable in theory but a lot of work,
> and it introduces a bug hazard every time someone changes these data
> structures.
Ah, I hadn't considered the references issue. Does make it quite hard :)