* @return List<String> of the internal column names.

   */

  public List<String> getColsFromSelectExpr(SelectOperator op) {

    List<String> cols = new ArrayList<String>();

    for (exprNodeDesc expr : exprList)

      cols = Utilities.mergeUniqElems(cols, expr.getCols());

    return cols;

  }

   * @return List<String> of the internal column names.

   */

  public List<String> getSelectColsFromChildren(SelectOperator op, List<String> colList) {

    List<String> cols = new ArrayList<String>();

    for (String col : colList) {

      // col is the internal name i.e. position within the expression list

      exprNodeDesc expr = selectExprs.get(Integer.parseInt(col));

      cols = Utilities.mergeUniqElems(cols, expr.getCols());

      col_list.add(new exprNodeColumnDesc(in.getType(), internalName));

    }

    Operator output = putOpInsertMap(OperatorFactory.getAndMakeChild(

    return output;

  }

          cols = Utilities.mergeUniqElems(cols, cppCtx.getPrunedColLists().get(child));

        }

      }

        // The input to the select does not matter. Go over the expressions

        // and return the ones which have a marked column

        cppCtx.getPrunedColLists().put(op, cppCtx.getSelectColsFromChildren(op, cols));

        return null;

      }

        }

      }

      cols = cppCtx.genColLists(op);

      // The input to the select does not matter. Go over the expressions

      // and return the ones which have a marked column

      cppCtx.getPrunedColLists().put(op, cppCtx.getSelectColsFromChildren(op, cols));

     

        return null;

     

      // do we need to prune the select operator?

      List<exprNodeDesc> originalColList = op.getConf().getColList();

      List<String> columns = new ArrayList<String>();

      for (exprNodeDesc expr : originalColList)

        Utilities.mergeUniqElems(columns, expr.getCols());

      // by now, 'prunedCols' are columns used by child operators, and 'columns'

      // are columns used by this select operator.

      if (cols.size() < originalOutputColumnNames.size()) {

        ArrayList<exprNodeDesc> newColList = new ArrayList<exprNodeDesc>();

        ArrayList<String> newOutputColumnNames = new ArrayList<String>();

        Vector<ColumnInfo> rs_oldsignature = op.getSchema().getSignature();

        Vector<ColumnInfo> rs_newsignature = new Vector<ColumnInfo>();

        RowResolver old_rr = cppCtx.getOpToParseCtxMap().get(op).getRR();

        RowResolver new_rr = new RowResolver();

        for(String col : cols){

          int index = originalOutputColumnNames.indexOf(col);

          newOutputColumnNames.add(col);

          newColList.add(originalColList.get(index));

          rs_newsignature.add(rs_oldsignature.get(index));

          String[] tabcol = old_rr.reverseLookup(col);

          ColumnInfo columnInfo = old_rr.get(tabcol[0], tabcol[1]);

          new_rr.put(tabcol[0], tabcol[1], columnInfo);

        }

        cppCtx.getOpToParseCtxMap().get(op).setRR(new_rr);

        op.getSchema().setSignature(rs_newsignature);

        handleChildren(op, cols, cppCtx);

      }

      return null;

    }

          valueInfo.getType(), nm[0], valueInfo.getIsPartitionCol()));

      colExprMap.put(internalName, colDesc);

    }

   

   

    SelectOperator sel =

      (SelectOperator)putOpInsertMap(OperatorFactory.getAndMakeChild(

          select, new RowSchema(inputRR.getColumnInfos()), input), inputRR);

   

      earr.add(exprDesc2);

      ArrayList<String> outputCols = new ArrayList<String>();

      for (int i = 0; i < earr.size(); i++)

        outputCols.add("_col"+i);

      Operator<selectDesc> op = OperatorFactory.get(selectDesc.class);

      op.setConf(selectCtx);

      // fileSinkOperator to dump the output of the select

      //fileSinkDesc fsd = new fileSinkDesc ("file:///tmp" + File.separator + System.getProperty("user.name") + File.separator + "TestFileSinkOperator",

      earr.add(exprDesc2);

      ArrayList<String> outputCols = new ArrayList<String>();

      for (int i = 0; i < earr.size(); i++)

        outputCols.add("_col"+i);

      Operator<selectDesc> op = OperatorFactory.get(selectDesc.class);

      op.setConf(selectCtx);

      // scriptOperator to echo the output of the select

      tableDesc scriptOutput = PlanUtils.getDefaultTableDesc("" + Utilities.tabCode, "a,b");

                                                     (tmpdir + "mapredplan3.out",

                                                      Utilities.defaultTd, false));

    Operator<selectDesc> op5 =  OperatorFactory.get

       (Utilities.makeList

        (getStringColumn(Utilities.ReduceField.ALIAS.toString()),

         new exprNodeFieldDesc(TypeInfoFactory.stringTypeInfo,

             new exprNodeColumnDesc(TypeInfoFactory.getListTypeInfo(

                 TypeInfoFactory.stringTypeInfo),

        PlanUtils.getDefaultTableDesc("" + Utilities.tabCode, "tkey,tvalue"),

        TextRecordReader.class),

     op1);

                                     Utilities.makeList(getStringColumn("key"),

                                                        getStringColumn("value")), outputColumns), op0);

    Utilities.addMapWork(mr, src, "a", op4);

    mr.setKeyDesc(op1.getConf().getKeySerializeInfo());