<wespvp(at)syntegra(dot)com> writes:
> If I bump up max_fsm_pages to 1,000,000 and run VACUUM ANALYZE, then would
> all 900,000 rows then be available for reused?
VACUUM will fill whatever FSM space is available. You do have to
restart the postmaster to get the increased FSM size to be allocated,
but you don't have to do any magic pushups beyond that.
regards, tom lane