This matches the rule for summing .count metrics. It means
that a minimum of 0% of the existing values must be non-null
in order for the new value to be non-null. That's good for
sums of exact counts.
Change-Id: Ic3f50888ada274a36e8f0385e6fffddf88ba6dfe
Reviewed-on: https://review.openstack.org/18747
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins