@Override
  public long getTableDevicesNumber(final String table) {
    final Long deviceNumber = tableDeviceNumber.get(table);
    return Objects.nonNull(deviceNumber) ? deviceNumber : 0;
  }
This class is used to record statistics within the SchemaRegion in Memory mode.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/rescon/MemSchemaRegionStatistics.java