At 02:07 PM 18/12/2002 +0100, Roel Rozendaal - IC&S wrote:
What MAX_FSM_* settings do you recommend?
I need to see the output of a VACUUM VERBOSE to know a good answer.
Otherwise, if you can give me an upper limit on the volume of mail received
each day, we could probably go with that. eg. if you receive 8GB of mail
each day, and it is all deleted/read/removed by the end of the day, and you
only vacuum daily, then I would suggest a minimum of 1,000,000 for
MAX_FSM_PAGES, and I would be inclined to set it to 2,000,000 to be safe
(this will use 8MB of shared memory). MAX_FSM_RELATIONS is probably OK as
is, but increasing it to 250 would give you some insurance.
In a high-transience database (email), the basic rule is to set
MAX_FSM_PAGES to the number of pages you will consume between vacuums; I
would also recommend a VACUUM VERBOSE be done whenever you restart the
database server process, to rebuild the FSM.
If you have any scheduled downtime, I do also strongly recommend a VACUUM
FULL, then try VACUUM and see if it kills the server. If it does not kill
the server, schedule VACUUM VERBOSE every hour. Once this has run for a
day, you can set MAX_FSM_PAGES to a much lower value.
Note that to set the MAX_FSM_* parameters you need to restart the
postmaster; so it might be good to do it all together.
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