private void regionMetricRegisterAndMark(Row op) {
      // Mark region metric
      String regionId = getRegionIdFromOp(op);
      if (regionId == null || regionId.isEmpty()) {
        return;
      }
      String regionRequestMeter = regionMeterName(regionId);
      regionMetricsLossyCounting.add(regionRequestMeter);
      registerAndMarkMeter(regionRequestMeter);
    }
Get regionId from Ops such as: get, put, delete.
@param op such as get, put or delete.
hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MetaTableMetrics.java