public boolean logicalEquals(Operator other) {
    return getClass().getName().equals(other.getClass().getName()) &&
        (conf == other.getConf() || (conf != null && other.getConf() != null &&
            conf.isSame(other.getConf())));
  }
Decides whether two operators are logically the same.
This can be used to merge same operators and avoid repeated computation.
ql/src/java/org/apache/hadoop/hive/ql/exec/Operator.java