Re: reading vacuum verbose output

Tsirkin Evgeny <tsurkin(at)mail(dot)jct(dot)ac(dot)il> writes:
> INFO: --Relation public.student2maslulsign_rashum_musmach_old--
> INFO: Pages 906: Changed 0, Empty 0; Tup 846: Vac 0, Keep 0, UnUsed 96035.
> Total CPU 0.03s/0.01u sec elapsed 0.04 sec.

> If there are unused tuples why i see the Changed 0 ?

Those are unused tuple slots, not tuples. They can be re-used, but they
won't be reclaimed unless the page they are in is truncated from the
table.

> (Note :The db is vacuumed every ~5 hours ver 7.3)

It would appear that you need a round of VACUUM FULL to get these tables
back down to a reasonable physical size, and in future vacuum more often.
Check your FSM settings too.

regards, tom lane