@Override
      protected Ratio getRatio() {
        int numerator = 0;
        int denominator = 0;
        for (Supplier<ThreadPoolExecutor> poolSupplier : metaPools) {
          ThreadPoolExecutor pool = poolSupplier.get();
          if (pool != null) {
            int activeCount = pool.getActiveCount();
            int maxPoolSize = pool.getMaximumPoolSize();
            /* The max thread usage ratio among meta lookup pools of all connections */
            if (numerator == 0 || (numerator * maxPoolSize) < (activeCount * denominator)) {
              numerator = activeCount;
              denominator = maxPoolSize;
            }
          }
        }
        return Ratio.of(numerator, denominator);
      }
Anticipated number of concurrent accessor threads
hbase-client/src/main/java/org/apache/hadoop/hbase/client/MetricsConnection.java