Jeffrey Baker <jwbaker@acm.org> writes:
> Well, if the table has an associated TOAST table, it is possible
> that it will suddenly start growing out of control, and nothing you
> can do with VACUUM will help. The TOAST system has a free space map
> (FSM) with some default number of pages it can track. If you exceed
> this number, it will become completely unable to reclaim space.
That's a gross misstatement.
If you have more pages with free space than the FSM can track, it will
forget about the ones with the least free space (at least until the next
vacuum tries to reload the info). This will very possibly lead to table
growth over time, but it's hardly the same as "completely unable to
reclaim space".
BTW, TOAST has nothing to do with this. Space in main tables and
toast tables is tracked alike.
regards, tom lane