Re: VACUUM FULL vs CLUSTER

you can see that at the end of vacuum log (sorry for my english)
...
INFO: free space map: 930 relations, 48827 pages stored; 60240 total pages
needed -- NEEDED!
-- I have already configured in postgresql.conf, you can see it below
DETAIL: Allocated FSM size: 1000 relations + 70000 pages = 475 kB shared
memory. -- ALLOCATED ACCORDING TO max_fsm_pages , etc
VACUUM

You probably must adjust your shared memory, coz the database need it, but
it depends on your database...

(I could be wrong, I'm learning postgresql, please, feel free to correct me)

-----Mensaje original-----
De: pgsql-performance-owner(at)postgresql(dot)org
[mailto:pgsql-performance-owner(at)postgresql(dot)org]En nombre de Stef
Enviado el: viernes, 23 de septiembre de 2005 14:18
Para: Bruno Wolff III
CC: Markus Benne; pgsql-performance(at)postgresql(dot)org
Asunto: Re: [PERFORM] VACUUM FULL vs CLUSTER

Bruno Wolff III mentioned :
=> > => If you have a proper FSM setting you shouldn't need to do vacuum
fulls
=> > => (unless you have an older version of postgres where index bloat
might
=> > => be an issue).

Thanks Alvaro and Bruno

I just want to clarify something that I also couldn't
find a clear cut answer for before.

What is a proper fsm setting?

Someone told me to set max_fsm_relations to the number of
relations in pg_class plus a few more to allow for new relations.
And max_fsm_pages to the number of rows in the biggest table I
want to vacuum, plus a few 1000's for extra room?

Where does this free space map sit? On the disk somewhere,
or in memory, or both.

I once set the max_fsm_pages very high by mistake, and postgres
then started up and used a _lot_ of shared memory, and I had to
increase shmmax. Is there abything to watch out for when bumping this
setting up a lot?

Kind Regards
Stefan

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TIP 5: don't forget to increase your free space map settings