Re: max_fsm_pages >800k ... ?

"Marc G. Fournier" <scrappy(at)postgresql(dot)org> writes:
> Without more information to provide at this time, does the following seem
> "unusual"?

> INFO: free space map: 252 relations, 411494 pages stored; 738640 total pages needed
> DETAIL: Allocated FSM size: 2000 relations + 400000 pages = 2463 kB shared memory.

What this is saying is that you'd need 738640 fsm_pages slots to
remember every single page that has a useful amount of free space.
However, you don't necessarily have to remember all those pages.
If you remember enough pages to satisfy insert/update requests
until the next VACUUM happens, then you're good.

I think the bottom-line question is "are you seeing any database
bloat?" If yes, increase max_fsm_pages; if no, worry not.

regards, tom lane