> > My conclusion would be that we need both:
> > 1. a fast system table only solution with physical/logical column id
> > 2. a tool that does the cleanup (e.g. vacuum)
>
> But the peak space usage during cleanup must still be 2X.
The difference for a cleanup would be, that it does not need to
be rolled back as a whole (like current vacuum).
A cleanup could be partly done, and resumed later, thus a sofisticated
cleanup could avoid 2X.
Andreas