Re: vacuum verbose relations reporting

On Tue, 26 Aug 2008, Tom Lane wrote:

> Jeff Frost <jeff@frostconsultingllc.com> writes:
>> No I actually mean that this part:
>> Current limits are:  600000 page slots, 10000 relations, using 4587 kB.
>> NOTICE:  max_fsm_relations(10000) equals the number of relations checked
>> HINT:  You have at least 10000 relations.  Consider increasing the
>
>> Just tells me that I'm equal or greater than max_fsm_relations.
>
> Yeah, because that's all that can be told from the contents of the
> shared free space map: it's full, but we have no idea how many other
> tables might have been competing for space in it.
>
>> But vacuum verbose does tell me how many page_slots are in use even
>> when it's greater than max_fsm_pages, so you know what value to use in
>> postgresql.conf for the fsm settings.
>
> Well, no :-(.  What that number is is the number of page slots that the
> relations that are in the FSM would have liked to have --- we have the
> "request" size as well as the "allocated" size for each such relation.
> We have no idea how many slots the relations that aren't in FSM might
> have liked to have.
>
> This whole design is pretty awful, of course (I can say that because it
> was my design :-().  There is work in progress to make the fixed-size
> FSM go away entirely in 8.4, which will certainly be a boon to DBAs.

Tom, is there an easy (or hard) way to count relations from all DBs by using
the system catalogs?

--
Jeff Frost, Owner     <jeff@frostconsultingllc.com>
Frost Consulting, LLC     http://www.frostconsultingllc.com/
Phone: 916-647-6411    FAX: 916-405-4032