public static String getOpNamePretty(Operator<?> op) {
    if (op instanceof TableScanOperator) {
      return op.toString() + " (" + ((TableScanOperator) op).getConf().getAlias() + ")";
    }
    return op.toString();
  }
Remove operator from the tree, disconnecting it from its
parents and children.
ql/src/java/org/apache/hadoop/hive/ql/exec/OperatorUtils.java