Thread: free space map usage
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Is there any way to determine how much of the free space map is currently in use?(ie. where and what it is tracking?) I vacuum on a regular basis but I never hold in terms of disk space usage. I jacked up the free space map pages but this doesn't appear to be working. shared_buffers = 29400 # 2*max_connections, min 16 max_fsm_relations = 1000 # min 10, fsm is free space map max_fsm_pages = 10000000 # min 1000, fsm is free space map - -- Jeremy M. Guthrie Systems Engineer Berbee 5520 Research Park Dr. Madison, WI 53711 Phone: 608-298-1061 Berbee...Decade 1. 1993-2003 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) iD8DBQE/jCo4qtjaBHGZBeURAj9EAKCL+tiioPO5K1YM1sn62yS0L1Ry5QCfVifq 22s22gFNFHAHquS+iiUZO6s= =AQ2Y -----END PGP SIGNATURE-----
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"Jeremy M. Guthrie" <jeremy.guthrie@berbee.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
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Tuesday 14 October 2003 02:16 pm, Tom Lane wrote: > "Jeremy M. Guthrie" <jeremy.guthrie@berbee.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? Yup. I still see no effect after restart. > regards, tom lane - -- Jeremy M. Guthrie Systems Engineer Berbee 5520 Research Park Dr. Madison, WI 53711 Phone: 608-298-1061 Berbee...Decade 1. 1993-2003 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) iD8DBQE/jFH8qtjaBHGZBeURAkKkAJ0cDa31C4VKxlHoByFaGY3EtQwMdwCgmA5k +Z9GUE3l7LIJVl9rII7d3TU= =gkIR -----END PGP SIGNATURE-----
On Tue, 2003-10-14 at 15:43, Jeremy M. Guthrie wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Tuesday 14 October 2003 02:16 pm, Tom Lane wrote:
> > "Jeremy M. Guthrie" <jeremy.guthrie@berbee.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?
> Yup. I still see no effect after restart.
>
Given that you knew of no way to determine how much free space map you
were using, what is your criteria for it to "appear to be working"? If
it's that space keeps growing, then your probably not vacuuming
frequently enough.
Robert Treat
--
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