private static void getAllOps(List<Operator> builder, Set<Operator> visited, Operator<?> op) {
    boolean added = visited.add(op);
    builder.add(op);
    if (!added) return;
    if (op.getNumChild() > 0) {
      List<Operator<?>> children = op.getChildOperators();
      for (int i = 0; i < children.size(); i++) {
        getAllOps(builder, visited, children.get(i));
      }
    }
  }
@param opToPartToSkewedPruner
         the opToSkewedPruner to set
ql/src/java/org/apache/hadoop/hive/ql/parse/ParseContext.java