private void updateMachineQuotaFactors(int rsSize) {
      if (rsSize != 0) {
        // TODO if use rs group, the cluster limit should be shared by the rs group
        machineQuotaFactor = 1.0 / rsSize;
      }
    }
This will call {@link #updateMachineQuotaFactors(int)}, and then update the table machine
factors as well. This relies on a more expensive query for ClusterMetrics.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/QuotaCache.java