Re: free space map usage

"Jeremy M. Guthrie" <jeremy(dot)guthrie(at)berbee(dot)com> writes:
> Is there any way to determine how much of the free space map is currently i=
> n=20
> use?(ie. where and what it is tracking?) I vacuum on a regular basis but I=
> =20
> never hold in terms of disk space usage.

Not in 7.3 AFAIR. In 7.4 a full-database VACUUM VERBOSE will end with
the info you want:

regression=# vacuum verbose;
... much cruft ...
INFO: free space map: 11 relations, 144 pages stored; 272 total pages needed
DETAIL: Allocated FSM size: 1000 relations + 20000 pages = 178 kB shared memory.
VACUUM
regression=#

This tells me I'm only using about 1% of the FSM space (272 out of 20000
page slots).

> I jacked up the free space map=20
> pages but this doesn't appear to be working.

You know you have to restart the postmaster to make those changes take
effect, right?

regards, tom lane