@Override
  public NonMatchedSmallTableIterator createNonMatchedSmallTableIterator(
      MatchTracker matchTracker) {
    throw new RuntimeException("Not applicable");
  }
Gets the partition Id into which to spill the big table row
@return partition Id
ql/src/java/org/apache/hadoop/hive/ql/exec/persistence/HybridHashTableContainer.java