> > The conventional VACUUM would then be something you do as part of a DB
> > reorganization (maybe once every month or so).
>
> Yes, but in other DB's if you UPDATE all rows in the table, you don't
> double the disk space.
Sure, but what is wrong with keeping the space allocated for the next
"UPDATE all rows", if that is something the application needs to do frequently ?
PostgreSQL needs more space on disc, but we knew that already :-)
Andreas