@Override
  public void put(Writable currentKey, Writable currentValue) throws SerDeException {
    directWriteHelper.setKeyValue(currentKey, currentValue);
    hashMap.put(directWriteHelper, -1);
  }
If we received data with tags from ReduceSinkOperators, no keys will match. This should
not happen, but is important enough that we want to find out and work around it if some
optimized change causes RSO to pass on tags.
ql/src/java/org/apache/hadoop/hive/ql/exec/persistence/MapJoinBytesTableContainer.java