public int compareTo(int elementNum1, TimestampColumnVector timestampColVector2,
      int elementNum2) {
    return asScratchTimestamp(elementNum1).compareTo(
        timestampColVector2.asScratchTimestamp(elementNum2));
  }
Compare a row to another TimestampColumnVector's row.
@param elementNum1
@param timestampColVector2
@param elementNum2
@return
storage-api/src/java/org/apache/hadoop/hive/ql/exec/vector/TimestampColumnVector.java