@Override
    public int hashCode() {
      return catName.hashCode() * 31 + dbName.hashCode() * 31 + tblName.hashCode() * 31 +
          colName.hashCode();
    }
Key object for the stats cache hashtable
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/AggregateStatsCache.java