Nicola Mauri <nicola(dot)mauri(at)saga(dot)it> writes:
> Data stored in the database didn't groove very much in the last months
> (pg_dump still generates a 4GB compressed file), but data files now
> occupies 20 GB on disk.
> I know that a vacuum full or a full dump/restore is needed to reclaim
> filesystem space. However, my question is: how this could have been
> happened?
What do you have max_fsm_pages set to? If it's too small, you'll get
bloat regardless of whether autovac is doing its thing.
regards, tom lane