Re: Vacuum full considered useful ;)

Patric de Waha <lists(at)p-dw(dot)com> writes:
> Yesterday I switched from 8.1 to 8.2. So I needed to dump the dbase
> and reimport it. The dbase after 4 months of running without "vacuum
> full"
> reached 60 gigabyte of diskspace. Now after a fresh import it only
> has 5 gigabyte!

> No wonder, I got IO problems with such a fragmentation.

Indeed, but routine VACUUM FULL is not the best answer. What this
suggests is that you don't have the FSM size (max_fsm_pages and possibly
max_fsm_relations) set high enough for your DB size. If it isn't
big enough then you'll "leak" reusable space over time. Also, if
you are using manual rather than autovacuum you might need to be
vacuuming more often.

regards, tom lane