public static int getSchemaHash(PartitionDesc part) {
    if (part == null) {
      return SchemaAwareCacheKey.NO_SCHEMA_HASH;
    } else {
      Object columnTypes = part.getProperties().get(META_TABLE_COLUMN_TYPES);
      if (columnTypes != null) {
        return columnTypes.toString().hashCode();
      } else {
        return SchemaAwareCacheKey.NO_SCHEMA_HASH;
      }
    }
  }
Takes a Path and looks up the PartitionDesc instance associated with it in a map of Path-&gt;PartitionDesc entries.
If it is not found (e.g. Path denotes a partition path, but map contains table level instances only) we will try
to do the same with the parent of this path, traversing up until there's a match, if any.
@param path the absolute path used for the look up
@param partitionDescMap the map
@return the PartitionDesc instance if found, null if not found
ql/src/java/org/apache/hadoop/hive/llap/LlapHiveUtils.java