public static void initializeMetadataProviderClass(List<Class<? extends RelNode>> nodeClasses) {
    // This will register the classes in the default Hive implementation
    DEFAULT.register(nodeClasses);
  }
This method can be called at startup time to pre-register all the
additional Hive classes (compared to Calcite core classes) that may
be visited during the planning phase.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/HiveDefaultRelMetadataProvider.java