@Override
  public void setSerde(MapJoinObjectSerDeContext keyCtx, MapJoinObjectSerDeContext valCtx)
      throws SerDeException {
    // Do nothing in this case.

  }
HashTableLoader for Tez constructs the hashtable from records read from
a broadcast edge.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/mapjoin/fast/VectorMapJoinFastTableContainer.java