private void loadOptimized(MapJoinBytesTableContainer container, ObjectInputStream in,
      Writable key, Writable value) throws Exception {
    int numKeys = in.readInt();
    for (int keyIndex = 0; keyIndex < numKeys; keyIndex++) {
      key.readFields(in);
      long numRows = in.readLong();
      for (long rowIndex = 0L; rowIndex < numRows; rowIndex++) {
        value.readFields(in);
        container.putRow(key, value);
      }
    }
  }
Loads the table container. Only used on MR path.
@param in Input stream.
@return Loaded table.
ql/src/java/org/apache/hadoop/hive/ql/exec/persistence/MapJoinTableContainerSerDe.java