Example #1
0
  @Test
  public void testSim4() throws Exception {
    PhysicalPlan php = new PhysicalPlan();

    PhysicalPlan ldGrpChain1 = GenPhyOp.loadedGrpChain();
    PhysicalPlan ldGrpChain2 = GenPhyOp.loadedGrpChain();

    php.merge(ldGrpChain1);
    php.merge(ldGrpChain2);

    POUnion un = GenPhyOp.topUnionOp();
    php.addAsLeaf(un);

    PhysicalPlan ldFil1 = GenPhyOp.loadedFilter();
    PhysicalPlan ldFil2 = GenPhyOp.loadedFilter();

    php.merge(ldFil1);
    php.connect(ldFil1.getLeaves().get(0), un);

    php.merge(ldFil2);
    php.connect(ldFil2.getLeaves().get(0), un);

    POStore st = GenPhyOp.topStoreOp();
    php.add(st);

    php.connect(un, st);
    run(php, "test/org/apache/pig/test/data/GoldenFiles/MRC4.gld");
  }
Example #2
0
  @Test
  public void testSim8() throws Exception {
    PhysicalPlan php = new PhysicalPlan();

    PhysicalPlan ldGrpChain1 = GenPhyOp.loadedGrpChain();
    PhysicalPlan ldGrpChain2 = GenPhyOp.loadedGrpChain();

    POLocalRearrange lr1 = GenPhyOp.topLocalRearrangeOp();
    POLocalRearrange lr2 = GenPhyOp.topLocalRearrangeOp();

    ldGrpChain1.addAsLeaf(lr1);
    ldGrpChain2.addAsLeaf(lr2);

    php.merge(ldGrpChain1);
    php.merge(ldGrpChain2);

    POGlobalRearrange gr = GenPhyOp.topGlobalRearrangeOp();
    php.addAsLeaf(gr);

    PhysicalPlan ldFil1 = GenPhyOp.loadedFilter();
    PhysicalPlan ldFil2 = GenPhyOp.loadedFilter();

    php.merge(ldFil1);
    php.connect(ldFil1.getLeaves().get(0), gr);

    php.merge(ldFil2);
    php.connect(ldFil2.getLeaves().get(0), gr);

    POPackage pk = GenPhyOp.topPackageOp();
    php.addAsLeaf(pk);

    POStore st = GenPhyOp.topStoreOp();
    php.addAsLeaf(st);
    run(php, "test/org/apache/pig/test/data/GoldenFiles/MRC8.gld");
  }
Example #3
0
  // Tests Single input case for both blocking and non-blocking
  // with both map and reduce phases
  @Test
  public void testSim1() throws Exception {
    PhysicalPlan php = new PhysicalPlan();
    POLoad ld = GenPhyOp.topLoadOp();
    php.add(ld);
    PhysicalPlan grpChain1 = GenPhyOp.grpChain();
    php.merge(grpChain1);

    php.connect(ld, grpChain1.getRoots().get(0));

    PhysicalOperator leaf = php.getLeaves().get(0);

    PhysicalPlan grpChain2 = GenPhyOp.grpChain();
    php.merge(grpChain2);

    php.connect(leaf, grpChain2.getRoots().get(0));

    leaf = php.getLeaves().get(0);
    POFilter fl = GenPhyOp.topFilterOp();
    php.add(fl);

    php.connect(leaf, fl);

    POStore st = GenPhyOp.topStoreOp();
    php.add(st);

    php.connect(fl, st);
    run(php, "test/org/apache/pig/test/data/GoldenFiles/MRC1.gld");
  }
Example #4
0
  /**
   * Change the algebriac function type for algebraic functions in map and combine In map and
   * combine the algebraic functions will be leaf of the plan
   *
   * @param fe
   * @param type
   * @throws PlanException
   */
  private static void changeFunc(POForEach fe, byte type) throws PlanException {
    for (PhysicalPlan plan : fe.getInputPlans()) {
      List<PhysicalOperator> leaves = plan.getLeaves();
      if (leaves == null || leaves.size() != 1) {
        int errCode = 2019;
        String msg = "Expected to find plan with single leaf. Found " + leaves.size() + " leaves.";
        throw new PlanException(msg, errCode, PigException.BUG);
      }

      PhysicalOperator leaf = leaves.get(0);
      if (leaf instanceof POProject) {
        continue;
      }
      if (!(leaf instanceof POUserFunc)) {
        int errCode = 2020;
        String msg =
            "Expected to find plan with UDF or project leaf. Found "
                + leaf.getClass().getSimpleName();
        throw new PlanException(msg, errCode, PigException.BUG);
      }

      POUserFunc func = (POUserFunc) leaf;
      try {
        func.setAlgebraicFunction(type);
      } catch (ExecException e) {
        int errCode = 2075;
        String msg = "Could not set algebraic function type.";
        throw new PlanException(msg, errCode, PigException.BUG, e);
      }
    }
  }
Example #5
0
  /**
   * Replace old POLocalRearrange with new pre-combine LR, add new map foreach, new
   * map-local-rearrange, and connect them
   *
   * @param mapPlan
   * @param preCombinerLR
   * @param mfe
   * @param mapAgg
   * @param mlr
   * @throws PlanException
   */
  private static void patchUpMap(
      PhysicalPlan mapPlan,
      POPreCombinerLocalRearrange preCombinerLR,
      POForEach mfe,
      POPartialAgg mapAgg,
      POLocalRearrange mlr)
      throws PlanException {
    POLocalRearrange oldLR = (POLocalRearrange) mapPlan.getLeaves().get(0);
    mapPlan.replace(oldLR, preCombinerLR);

    mapPlan.add(mfe);
    mapPlan.connect(preCombinerLR, mfe);

    // the operator before local rearrange
    PhysicalOperator opBeforeLR = mfe;

    if (mapAgg != null) {
      mapPlan.add(mapAgg);
      mapPlan.connect(mfe, mapAgg);
      opBeforeLR = mapAgg;
    }

    mapPlan.add(mlr);
    mapPlan.connect(opBeforeLR, mlr);
  }
    /** Configures the Reduce plan, the POPackage operator and the reporter thread */
    @SuppressWarnings("unchecked")
    @Override
    protected void setup(Context context) throws IOException, InterruptedException {
      super.setup(context);
      inIllustrator = inIllustrator(context);
      if (inIllustrator) pack = getPack(context);
      Configuration jConf = context.getConfiguration();
      SpillableMemoryManager.configure(ConfigurationUtil.toProperties(jConf));
      context
          .getConfiguration()
          .set(
              PigConstants.TASK_INDEX,
              Integer.toString(context.getTaskAttemptID().getTaskID().getId()));
      sJobContext = context;
      sJobConfInternal.set(context.getConfiguration());
      sJobConf = context.getConfiguration();
      try {
        PigContext.setPackageImportList(
            (ArrayList<String>) ObjectSerializer.deserialize(jConf.get("udf.import.list")));
        pigContext = (PigContext) ObjectSerializer.deserialize(jConf.get("pig.pigContext"));

        // This attempts to fetch all of the generated code from the distributed cache, and resolve
        // it
        SchemaTupleBackend.initialize(jConf, pigContext);

        if (rp == null)
          rp = (PhysicalPlan) ObjectSerializer.deserialize(jConf.get("pig.reducePlan"));
        stores = PlanHelper.getPhysicalOperators(rp, POStore.class);

        if (!inIllustrator)
          pack = (POPackage) ObjectSerializer.deserialize(jConf.get("pig.reduce.package"));
        // To be removed
        if (rp.isEmpty()) log.debug("Reduce Plan empty!");
        else {
          ByteArrayOutputStream baos = new ByteArrayOutputStream();
          rp.explain(baos);
          log.debug(baos.toString());
        }
        pigReporter = new ProgressableReporter();
        if (!(rp.isEmpty())) {
          roots = rp.getRoots().toArray(new PhysicalOperator[1]);
          leaf = rp.getLeaves().get(0);
        }

        // Get the UDF specific context
        MapRedUtil.setupUDFContext(jConf);

      } catch (IOException ioe) {
        String msg = "Problem while configuring reduce plan.";
        throw new RuntimeException(msg, ioe);
      }

      log.info(
          "Aliases being processed per job phase (AliasName[line,offset]): "
              + jConf.get("pig.alias.location"));

      Utils.setDefaultTimeZone(PigMapReduce.sJobConfInternal.get());
    }
Example #7
0
  @Test
  public void testSortUDF1() throws Exception {
    PhysicalPlan php = new PhysicalPlan();
    PhysicalPlan ldFil1 = GenPhyOp.loadedFilter();
    php.merge(ldFil1);

    // set up order by *
    String funcName = WeirdComparator.class.getName();
    POUserComparisonFunc comparator =
        new POUserComparisonFunc(
            new OperatorKey("", r.nextLong()), -1, null, new FuncSpec(funcName));
    POSort sort =
        new POSort(
            new OperatorKey("", r.nextLong()),
            -1,
            ldFil1.getLeaves(),
            null,
            new ArrayList<Boolean>(),
            comparator);
    sort.setRequestedParallelism(20);
    PhysicalPlan nesSortPlan = new PhysicalPlan();
    POProject topPrj = new POProject(new OperatorKey("", r.nextLong()));
    topPrj.setColumn(1);
    topPrj.setOverloaded(true);
    topPrj.setResultType(DataType.TUPLE);
    nesSortPlan.add(topPrj);

    POProject prjStar2 = new POProject(new OperatorKey("", r.nextLong()));
    prjStar2.setResultType(DataType.TUPLE);
    prjStar2.setStar(true);
    nesSortPlan.add(prjStar2);

    nesSortPlan.connect(topPrj, prjStar2);
    List<PhysicalPlan> nesSortPlanLst = new ArrayList<PhysicalPlan>();
    nesSortPlanLst.add(nesSortPlan);

    sort.setSortPlans(nesSortPlanLst);

    php.add(sort);
    php.connect(ldFil1.getLeaves().get(0), sort);
    // have a foreach which takes the sort output
    // and send it two two udfs
    List<String> udfs = new ArrayList<String>();
    udfs.add(COUNT.class.getName());
    udfs.add(SUM.class.getName());
    POForEach fe3 = GenPhyOp.topForEachOPWithUDF(udfs);
    php.add(fe3);
    php.connect(sort, fe3);

    // add a group above the foreach
    PhysicalPlan grpChain1 = GenPhyOp.grpChain();
    php.merge(grpChain1);
    php.connect(fe3, grpChain1.getRoots().get(0));

    udfs.clear();
    udfs.add(AVG.class.getName());
    POForEach fe4 = GenPhyOp.topForEachOPWithUDF(udfs);
    php.addAsLeaf(fe4);

    PhysicalPlan grpChain2 = GenPhyOp.grpChain();
    php.merge(grpChain2);
    php.connect(fe4, grpChain2.getRoots().get(0));

    udfs.clear();
    udfs.add(GFCross.class.getName() + "('1')");
    POForEach fe5 = GenPhyOp.topForEachOPWithUDF(udfs);
    php.addAsLeaf(fe5);

    POStore st = GenPhyOp.topStoreOp();
    php.addAsLeaf(st);
    run(php, "test/org/apache/pig/test/data/GoldenFiles/MRC15.gld");
  }
Example #8
0
  @Test
  public void testRun2() throws Exception {
    PhysicalPlan php = new PhysicalPlan();

    PhysicalPlan part1 = new PhysicalPlan();
    POLoad lC = GenPhyOp.topLoadOp();
    POFilter fC = GenPhyOp.topFilterOp();
    POLocalRearrange lrC = GenPhyOp.topLocalRearrangeOp();
    POGlobalRearrange grC = GenPhyOp.topGlobalRearrangeOp();
    POPackage pkC = GenPhyOp.topPackageOp();
    part1.add(lC);
    part1.add(fC);
    part1.connect(lC, fC);
    part1.add(lrC);
    part1.connect(fC, lrC);
    part1.add(grC);
    part1.connect(lrC, grC);
    part1.add(pkC);
    part1.connect(grC, pkC);

    POPackage pkD = GenPhyOp.topPackageOp();
    POLocalRearrange lrD = GenPhyOp.topLocalRearrangeOp();
    POGlobalRearrange grD = GenPhyOp.topGlobalRearrangeOp();
    POLoad lD = GenPhyOp.topLoadOp();
    part1.add(lD);
    part1.add(lrD);
    part1.connect(lD, lrD);

    part1.add(grD);
    part1.connect(lrD, grD);
    part1.add(pkD);
    part1.connect(grD, pkD);
    part1.connect(pkD, grC);

    POLoad lA = GenPhyOp.topLoadOp();
    POLoad lB = GenPhyOp.topLoadOp();

    // POLoad lC = lA;
    POFilter fA = GenPhyOp.topFilterOp();

    POLocalRearrange lrA = GenPhyOp.topLocalRearrangeOp();
    POLocalRearrange lrB = GenPhyOp.topLocalRearrangeOp();

    POGlobalRearrange grAB = GenPhyOp.topGlobalRearrangeOp();

    POPackage pkAB = GenPhyOp.topPackageOp();

    POFilter fAB = GenPhyOp.topFilterOp();
    POUnion unABC = GenPhyOp.topUnionOp();

    php.add(lA);
    php.add(lB);

    php.add(fA);

    php.connect(lA, fA);

    php.add(lrA);
    php.add(lrB);

    php.connect(fA, lrA);
    php.connect(lB, lrB);

    php.add(grAB);
    php.connect(lrA, grAB);
    php.connect(lrB, grAB);

    php.add(pkAB);
    php.connect(grAB, pkAB);

    php.add(fAB);
    php.connect(pkAB, fAB);

    php.merge(part1);

    List<PhysicalOperator> leaves = new ArrayList<PhysicalOperator>();
    for (PhysicalOperator phyOp : php.getLeaves()) {
      leaves.add(phyOp);
    }

    php.add(unABC);
    for (PhysicalOperator physicalOperator : leaves) {
      php.connect(physicalOperator, unABC);
    }

    POStore st = GenPhyOp.topStoreOp();

    php.add(st);
    php.connect(unABC, st);
    run(php, "test/org/apache/pig/test/data/GoldenFiles/MRC11.gld");
  }
Example #9
0
  /**
   * Algebraic functions and distinct in nested plan of a foreach are partially computed in the map
   * and combine phase. A new foreach statement with initial and intermediate forms of algebraic
   * functions are added to map and combine plans respectively.
   *
   * <p>If bag portion of group-by result is projected or a non algebraic expression/udf has bag as
   * input, combiner will not be used. This is because the use of combiner in such case is likely to
   * degrade performance as there will not be much reduction in data size in combine stage to offset
   * the cost of the additional number of times (de)serialization is done.
   *
   * <p>Major areas for enhancement: 1. use of combiner in cogroup 2. queries with order-by, limit
   * or sort in a nested foreach after group-by 3. case where group-by is followed by filter that
   * has algebraic expression
   */
  public static void addCombiner(
      PhysicalPlan mapPlan,
      PhysicalPlan reducePlan,
      PhysicalPlan combinePlan,
      CompilationMessageCollector messageCollector,
      boolean doMapAgg)
      throws VisitorException {

    // part one - check if this MR job represents a group-by + foreach. Find
    // the POLocalRearrange in the map. I'll need it later.
    List<PhysicalOperator> mapLeaves = mapPlan.getLeaves();
    if (mapLeaves == null || mapLeaves.size() != 1) {
      messageCollector.collect(
          "Expected map to have single leaf", MessageType.Warning, PigWarning.MULTI_LEAF_MAP);
      return;
    }
    PhysicalOperator mapLeaf = mapLeaves.get(0);
    if (!(mapLeaf instanceof POLocalRearrange)) {
      return;
    }
    POLocalRearrange rearrange = (POLocalRearrange) mapLeaf;

    List<PhysicalOperator> reduceRoots = reducePlan.getRoots();
    if (reduceRoots.size() != 1) {
      messageCollector.collect(
          "Expected reduce to have single root", MessageType.Warning, PigWarning.MULTI_ROOT_REDUCE);
      return;
    }

    // I expect that the first root should always be a POPackage. If not, I
    // don't know what's going on, so I'm out of here.
    PhysicalOperator root = reduceRoots.get(0);
    if (!(root instanceof POPackage)) {
      messageCollector.collect(
          "Expected reduce root to be a POPackage",
          MessageType.Warning,
          PigWarning.NON_PACKAGE_REDUCE_PLAN_ROOT);
      return;
    }
    POPackage pack = (POPackage) root;

    List<PhysicalOperator> packSuccessors = reducePlan.getSuccessors(root);
    if (packSuccessors == null || packSuccessors.size() != 1) {
      return;
    }
    PhysicalOperator successor = packSuccessors.get(0);

    if (successor instanceof POLimit) {
      // POLimit is acceptable, as long has it has a single foreach as
      // successor
      List<PhysicalOperator> limitSucs = reducePlan.getSuccessors(successor);
      if (limitSucs != null && limitSucs.size() == 1 && limitSucs.get(0) instanceof POForEach) {
        // the code below will now further examine the foreach
        successor = limitSucs.get(0);
      }
    }
    if (successor instanceof POForEach) {
      POForEach foreach = (POForEach) successor;
      List<PhysicalPlan> feInners = foreach.getInputPlans();

      // find algebraic operators and also check if the foreach statement
      // is suitable for combiner use
      List<Pair<PhysicalOperator, PhysicalPlan>> algebraicOps = findAlgebraicOps(feInners);
      if (algebraicOps == null || algebraicOps.size() == 0) {
        // the plan is not combinable or there is nothing to combine
        // we're done
        return;
      }
      if (combinePlan != null && combinePlan.getRoots().size() != 0) {
        messageCollector.collect(
            "Wasn't expecting to find anything already " + "in the combiner!",
            MessageType.Warning,
            PigWarning.NON_EMPTY_COMBINE_PLAN);
        return;
      }

      LOG.info("Choosing to move algebraic foreach to combiner");
      try {
        // replace PODistinct->Project[*] with distinct udf (which is Algebraic)
        for (Pair<PhysicalOperator, PhysicalPlan> op2plan : algebraicOps) {
          if (!(op2plan.first instanceof PODistinct)) {
            continue;
          }
          DistinctPatcher distinctPatcher = new DistinctPatcher(op2plan.second);
          distinctPatcher.visit();
          if (distinctPatcher.getDistinct() == null) {
            int errCode = 2073;
            String msg =
                "Problem with replacing distinct operator with distinct built-in function.";
            throw new PlanException(msg, errCode, PigException.BUG);
          }
          op2plan.first = distinctPatcher.getDistinct();
        }

        // create new map foreach
        POForEach mfe = createForEachWithGrpProj(foreach, rearrange.getKeyType());
        Map<PhysicalOperator, Integer> op2newpos = Maps.newHashMap();
        Integer pos = 1;
        // create plan for each algebraic udf and add as inner plan in map-foreach
        for (Pair<PhysicalOperator, PhysicalPlan> op2plan : algebraicOps) {
          PhysicalPlan udfPlan = createPlanWithPredecessors(op2plan.first, op2plan.second);
          mfe.addInputPlan(udfPlan, false);
          op2newpos.put(op2plan.first, pos++);
        }
        changeFunc(mfe, POUserFunc.INITIAL);

        // since we will only be creating SingleTupleBag as input to
        // the map foreach, we should flag the POProjects in the map
        // foreach inner plans to also use SingleTupleBag
        for (PhysicalPlan mpl : mfe.getInputPlans()) {
          try {
            new fixMapProjects(mpl).visit();
          } catch (VisitorException e) {
            int errCode = 2089;
            String msg = "Unable to flag project operator to use single tuple bag.";
            throw new PlanException(msg, errCode, PigException.BUG, e);
          }
        }

        // create new combine foreach
        POForEach cfe = createForEachWithGrpProj(foreach, rearrange.getKeyType());
        // add algebraic functions with appropriate projection
        addAlgebraicFuncToCombineFE(cfe, op2newpos);
        changeFunc(cfe, POUserFunc.INTERMEDIATE);

        // fix projection and function time for algebraic functions in reduce foreach
        for (Pair<PhysicalOperator, PhysicalPlan> op2plan : algebraicOps) {
          setProjectInput(op2plan.first, op2plan.second, op2newpos.get(op2plan.first));
          byte resultType = op2plan.first.getResultType();
          ((POUserFunc) op2plan.first).setAlgebraicFunction(POUserFunc.FINAL);
          op2plan.first.setResultType(resultType);
        }

        // we have modified the foreach inner plans - so set them again
        // for the foreach so that foreach can do any re-initialization
        // around them.
        // FIXME - this is a necessary evil right now because the leaves
        // are explicitly stored in the POForeach as a list rather than
        // computed each time at run time from the plans for
        // optimization. Do we want to have the Foreach compute the
        // leaves each time and have Java optimize it (will Java
        // optimize?)?
        mfe.setInputPlans(mfe.getInputPlans());
        cfe.setInputPlans(cfe.getInputPlans());
        foreach.setInputPlans(foreach.getInputPlans());

        // tell POCombinerPackage which fields need projected and which
        // placed in bags. First field is simple project rest need to go
        // into bags
        int numFields = algebraicOps.size() + 1; // algebraic funcs + group key
        boolean[] bags = new boolean[numFields];
        bags[0] = false;
        for (int i = 1; i < numFields; i++) {
          bags[i] = true;
        }

        // Use the POCombiner package in the combine plan
        // as it needs to act differently than the regular
        // package operator.
        CombinerPackager pkgr = new CombinerPackager(pack.getPkgr(), bags);
        POPackage combinePack = pack.clone();
        combinePack.setPkgr(pkgr);
        combinePack.setParentPlan(null);

        combinePlan.add(combinePack);
        combinePlan.add(cfe);
        combinePlan.connect(combinePack, cfe);

        // No need to connect projections in cfe to cp, because
        // PigCombiner directly attaches output from package to
        // root of remaining plan.

        POLocalRearrange mlr = getNewRearrange(rearrange);
        POPartialAgg mapAgg = null;
        if (doMapAgg) {
          mapAgg = createPartialAgg(cfe);
        }

        // A specialized local rearrange operator will replace
        // the normal local rearrange in the map plan. This behaves
        // like the regular local rearrange in the getNext()
        // as far as getting its input and constructing the
        // "key" out of the input. It then returns a tuple with
        // two fields - the key in the first position and the
        // "value" inside a bag in the second position. This output
        // format resembles the format out of a Package. This output
        // will feed to the map foreach which expects this format.
        // If the key field isn't in the project of the combiner or map foreach,
        // it is added to the end (This is required so that we can
        // set up the inner plan of the new Local Rearrange leaf in the map
        // and combine plan to contain just the project of the key).
        patchUpMap(mapPlan, getPreCombinerLR(rearrange), mfe, mapAgg, mlr);
        POLocalRearrange clr = getNewRearrange(rearrange);
        clr.setParentPlan(null);
        combinePlan.add(clr);
        combinePlan.connect(cfe, clr);

        // Change the package operator in the reduce plan to
        // be the POCombiner package, as it needs to act
        // differently than the regular package operator.
        pack.setPkgr(pkgr.clone());
      } catch (Exception e) {
        int errCode = 2018;
        String msg = "Internal error. Unable to introduce the combiner for optimization.";
        throw new OptimizerException(msg, errCode, PigException.BUG, e);
      }
    }
  }
      @Override
      protected void execute(LogicalExpression op) throws FrontendException {
        if (op instanceof UserFuncExpression) {
          UserFuncExpression udf = (UserFuncExpression) op;
          if (!udf.getEvalFunc().allowCompileTimeCalculation()) {
            return;
          }
        }
        boolean valSet = false;
        Object val = null;
        if (currentWalker.getPlan().getSuccessors(op) != null) {
          // If has successors and all successors are constant, calculate the constant
          for (Operator succ : currentWalker.getPlan().getSuccessors(op)) {
            if (!(succ instanceof ConstantExpression)) {
              return;
            }
          }
          // All successors are constant, calculate the value
          OperatorPlan expLogicalPlan = new LogicalExpressionPlan();
          ((BaseOperatorPlan) currentWalker.getPlan())
              .moveTree(op, (BaseOperatorPlan) expLogicalPlan);
          PhysicalPlan expPhysicalPlan = new PhysicalPlan();
          Map<Operator, PhysicalOperator> logToPhyMap = new HashMap<Operator, PhysicalOperator>();
          PlanWalker childWalker = new ReverseDependencyOrderWalkerWOSeenChk(expLogicalPlan);

          // Save the old walker and use childWalker as current Walker
          pushWalker(childWalker);
          ExpToPhyTranslationVisitor expTranslationVisitor =
              new ExpToPhyTranslationVisitor(
                  expLogicalPlan, childWalker, currentOp, expPhysicalPlan, logToPhyMap);
          expTranslationVisitor.visit();
          popWalker();
          PhysicalOperator root = expPhysicalPlan.getLeaves().get(0);
          try {
            UDFContext.getUDFContext()
                .addJobConf(ConfigurationUtil.toConfiguration(pc.getProperties(), true));
            PigHadoopLogger pigHadoopLogger = PigHadoopLogger.getInstance();
            PhysicalOperator.setPigLogger(pigHadoopLogger);
            setDefaultTimeZone();
            val = root.getNext(root.getResultType()).result;
            restoreDefaultTimeZone();
            UDFContext.getUDFContext().addJobConf(null);
          } catch (ExecException e) {
            throw new FrontendException(e);
          }
          valSet = true;
        } else if (op instanceof UserFuncExpression) {
          // If solo UDF, calculate UDF
          UserFuncExpression udf = (UserFuncExpression) op;
          try {
            UDFContext.getUDFContext()
                .addJobConf(ConfigurationUtil.toConfiguration(pc.getProperties(), true));
            setDefaultTimeZone();
            val = udf.getEvalFunc().exec(null);
            restoreDefaultTimeZone();
            UDFContext.getUDFContext().addJobConf(null);
          } catch (IOException e) {
            throw new FrontendException(e);
          }
          valSet = true;
        }
        if (valSet) {
          ConstantExpression constantExpr;
          constantExpr = new ConstantExpression(currentWalker.getPlan(), val);
          constantExpr.inheritSchema(op);
          currentWalker.getPlan().replace(op, constantExpr);
        }
      }