@Override public synchronized PropertyMap fetchProperties(String mapKey, Function<String, PropertySchema> getSchema) {
    byte[] bytes = properties.get(mapKey);
    if (bytes != null) {
      PropertyMap map = deserialize(bytes, getSchema);
      // if read dirty, write back to make clean
      if (map.isDirty()) {
        saveProperties(mapKey, map);
      }
      return map;
    }
    return null;
  }
The digests for the stored maps.
standalone-metastore/metastore-common/src/test/java/org/apache/hadoop/hive/metastore/properties/TransientPropertyStore.java