public boolean addElement(HashTableElement h) {
      this.batch[this.currentIndex++] = h;
      return (this.currentIndex == BATCH_SIZE);
    }
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/VectorMapJoinFastHashTableLoader.java