Ejemplo n.º 1
0
  protected RelationalNode convertNode(PlanNode node)
      throws TeiidComponentException, TeiidProcessingException {

    RelationalNode processNode = null;

    switch (node.getType()) {
      case NodeConstants.Types.PROJECT:
        GroupSymbol intoGroup = (GroupSymbol) node.getProperty(NodeConstants.Info.INTO_GROUP);
        if (intoGroup != null) {
          try {
            Insert insert = (Insert) node.getFirstChild().getProperty(Info.VIRTUAL_COMMAND);
            List<ElementSymbol> allIntoElements = insert.getVariables();

            Object groupID = intoGroup.getMetadataID();
            Object modelID = metadata.getModelID(groupID);
            String modelName = metadata.getFullName(modelID);
            if (metadata.isVirtualGroup(groupID)) {
              InsertPlanExecutionNode ipen = new InsertPlanExecutionNode(getID(), metadata);
              ipen.setProcessorPlan(
                  (ProcessorPlan) node.getFirstChild().getProperty(Info.PROCESSOR_PLAN));
              ipen.setReferences(insert.getValues());
              processNode = ipen;
            } else {
              ProjectIntoNode pinode = new ProjectIntoNode(getID());
              pinode.setIntoGroup(intoGroup);
              pinode.setIntoElements(allIntoElements);
              pinode.setModelName(modelName);
              pinode.setConstraint((Criteria) node.getProperty(Info.CONSTRAINT));
              processNode = pinode;
              SourceCapabilities caps = capFinder.findCapabilities(modelName);
              if (caps.supportsCapability(Capability.INSERT_WITH_ITERATOR)) {
                pinode.setMode(org.teiid.query.processor.relational.ProjectIntoNode.Mode.ITERATOR);
              } else if (caps.supportsCapability(Capability.BATCHED_UPDATES)) {
                pinode.setMode(org.teiid.query.processor.relational.ProjectIntoNode.Mode.BATCH);
              } else {
                pinode.setMode(org.teiid.query.processor.relational.ProjectIntoNode.Mode.SINGLE);
              }
            }
          } catch (QueryMetadataException e) {
            throw new TeiidComponentException(QueryPlugin.Event.TEIID30247, e);
          }

        } else {
          List<Expression> symbols = (List) node.getProperty(NodeConstants.Info.PROJECT_COLS);

          ProjectNode pnode = new ProjectNode(getID());
          pnode.setSelectSymbols(symbols);
          processNode = pnode;

          if (node.hasBooleanProperty(Info.HAS_WINDOW_FUNCTIONS)) {
            WindowFunctionProjectNode wfpn = new WindowFunctionProjectNode(getID());

            // with partial projection the window function may already be pushed, we'll check for
            // that here
            ArrayList<Expression> filtered = new ArrayList<Expression>();
            List<Expression> childSymbols =
                (List) node.getFirstChild().getProperty(NodeConstants.Info.OUTPUT_COLS);
            for (Expression ex : symbols) {
              ex = SymbolMap.getExpression(ex);
              if (childSymbols.contains(ex)) {
                continue;
              }
              filtered.add(ex);
            }
            Set<WindowFunction> windowFunctions =
                RuleAssignOutputElements.getWindowFunctions(filtered);
            if (!windowFunctions.isEmpty()) {
              // TODO: check for selecting all window functions
              List<Expression> outputElements = new ArrayList<Expression>(windowFunctions);
              // collect the other projected expressions
              for (Expression singleElementSymbol :
                  (List<Expression>) node.getFirstChild().getProperty(Info.OUTPUT_COLS)) {
                outputElements.add(singleElementSymbol);
              }
              wfpn.setElements(outputElements);
              wfpn.init();
              pnode.addChild(wfpn);
            }
          }
        }
        break;

      case NodeConstants.Types.JOIN:
        JoinType jtype = (JoinType) node.getProperty(NodeConstants.Info.JOIN_TYPE);
        JoinStrategyType stype =
            (JoinStrategyType) node.getProperty(NodeConstants.Info.JOIN_STRATEGY);

        JoinNode jnode = new JoinNode(getID());
        jnode.setJoinType(jtype);
        jnode.setLeftDistinct(node.hasBooleanProperty(NodeConstants.Info.IS_LEFT_DISTINCT));
        jnode.setRightDistinct(node.hasBooleanProperty(NodeConstants.Info.IS_RIGHT_DISTINCT));
        List joinCrits = (List) node.getProperty(NodeConstants.Info.JOIN_CRITERIA);
        String depValueSource =
            (String) node.getProperty(NodeConstants.Info.DEPENDENT_VALUE_SOURCE);
        SortOption leftSort = (SortOption) node.getProperty(NodeConstants.Info.SORT_LEFT);
        if (stype == JoinStrategyType.MERGE || stype == JoinStrategyType.ENHANCED_SORT) {
          MergeJoinStrategy mjStrategy = null;
          if (stype.equals(JoinStrategyType.ENHANCED_SORT)) {
            EnhancedSortMergeJoinStrategy esmjStrategy =
                new EnhancedSortMergeJoinStrategy(
                    leftSort, (SortOption) node.getProperty(NodeConstants.Info.SORT_RIGHT));
            esmjStrategy.setSemiDep(node.hasBooleanProperty(Info.IS_SEMI_DEP));
            mjStrategy = esmjStrategy;
          } else {
            mjStrategy =
                new MergeJoinStrategy(
                    leftSort, (SortOption) node.getProperty(NodeConstants.Info.SORT_RIGHT), false);
          }
          jnode.setJoinStrategy(mjStrategy);
          List leftExpressions = (List) node.getProperty(NodeConstants.Info.LEFT_EXPRESSIONS);
          List rightExpressions = (List) node.getProperty(NodeConstants.Info.RIGHT_EXPRESSIONS);
          jnode.setJoinExpressions(leftExpressions, rightExpressions);
          joinCrits = (List) node.getProperty(NodeConstants.Info.NON_EQUI_JOIN_CRITERIA);
        } else if (stype == JoinStrategyType.NESTED_TABLE) {
          NestedTableJoinStrategy ntjStrategy = new NestedTableJoinStrategy();
          jnode.setJoinStrategy(ntjStrategy);
          SymbolMap references = (SymbolMap) node.getProperty(Info.LEFT_NESTED_REFERENCES);
          ntjStrategy.setLeftMap(references);
          references = (SymbolMap) node.getProperty(Info.RIGHT_NESTED_REFERENCES);
          ntjStrategy.setRightMap(references);
        } else {
          NestedLoopJoinStrategy nljStrategy = new NestedLoopJoinStrategy();
          jnode.setJoinStrategy(nljStrategy);
        }
        Criteria joinCrit = Criteria.combineCriteria(joinCrits);
        jnode.setJoinCriteria(joinCrit);

        processNode = jnode;

        jnode.setDependentValueSource(depValueSource);

        break;

      case NodeConstants.Types.ACCESS:
        ProcessorPlan plan = (ProcessorPlan) node.getProperty(NodeConstants.Info.PROCESSOR_PLAN);
        if (plan != null) {

          PlanExecutionNode peNode = null;

          Criteria crit = (Criteria) node.getProperty(NodeConstants.Info.PROCEDURE_CRITERIA);

          if (crit != null) {
            List references = (List) node.getProperty(NodeConstants.Info.PROCEDURE_INPUTS);
            List defaults = (List) node.getProperty(NodeConstants.Info.PROCEDURE_DEFAULTS);

            peNode = new DependentProcedureExecutionNode(getID(), crit, references, defaults);
          } else {
            peNode = new PlanExecutionNode(getID());
          }

          peNode.setProcessorPlan(plan);
          processNode = peNode;

        } else {
          AccessNode aNode = null;
          Command command = (Command) node.getProperty(NodeConstants.Info.ATOMIC_REQUEST);
          Object modelID = node.getProperty(NodeConstants.Info.MODEL_ID);
          if (modelID != null) {
            String fullName = metadata.getFullName(modelID);
            if (!capFinder.isValid(fullName)) {
              // TODO: we ideally want to handle the partial resutls case here differently
              //      by adding a null node / and a source warning
              //      for now it's just as easy to say that the user needs to take steps to
              //      return static capabilities
              SourceCapabilities caps = capFinder.findCapabilities(fullName);
              Exception cause = null;
              if (caps != null) {
                cause = (Exception) caps.getSourceProperty(Capability.INVALID_EXCEPTION);
              }
              throw new QueryPlannerException(
                  QueryPlugin.Event.TEIID30498,
                  cause,
                  QueryPlugin.Util.gs(QueryPlugin.Event.TEIID30498, fullName));
            }
          }
          EvaluatableVisitor ev = null;
          if (node.hasBooleanProperty(NodeConstants.Info.IS_DEPENDENT_SET)) {
            if (command instanceof StoredProcedure) {
              List references = (List) node.getProperty(NodeConstants.Info.PROCEDURE_INPUTS);
              List defaults = (List) node.getProperty(NodeConstants.Info.PROCEDURE_DEFAULTS);
              Criteria crit = (Criteria) node.getProperty(NodeConstants.Info.PROCEDURE_CRITERIA);

              DependentProcedureAccessNode depAccessNode =
                  new DependentProcedureAccessNode(getID(), crit, references, defaults);
              processNode = depAccessNode;
              aNode = depAccessNode;
            } else {
              // create dependent access node
              DependentAccessNode depAccessNode = new DependentAccessNode(getID());

              if (modelID != null) {
                depAccessNode.setPushdown(
                    CapabilitiesUtil.supports(
                        Capability.DEPENDENT_JOIN, modelID, metadata, capFinder));
                depAccessNode.setMaxSetSize(
                    CapabilitiesUtil.getMaxInCriteriaSize(modelID, metadata, capFinder));
                depAccessNode.setMaxPredicates(
                    CapabilitiesUtil.getMaxDependentPredicates(modelID, metadata, capFinder));
                depAccessNode.setUseBindings(
                    CapabilitiesUtil.supports(
                        Capability.DEPENDENT_JOIN_BINDINGS, modelID, metadata, capFinder));
                // TODO: allow the translator to drive this property
                // simplistic check of whether this query is complex to re-execute
                Query query = (Query) command;
                if (query.getGroupBy() != null
                    || query.getFrom().getClauses().size() > 1
                    || !(query.getFrom().getClauses().get(0) instanceof UnaryFromClause)
                    || query.getWith() != null) {
                  depAccessNode.setComplexQuery(true);
                } else {
                  // check to see if there in an index on at least one of the dependent sets
                  Set<GroupSymbol> groups = new HashSet<GroupSymbol>(query.getFrom().getGroups());
                  boolean found = false;
                  for (Criteria crit : Criteria.separateCriteriaByAnd(query.getCriteria())) {
                    if (crit instanceof DependentSetCriteria) {
                      DependentSetCriteria dsc = (DependentSetCriteria) crit;
                      if (NewCalculateCostUtil.getKeyUsed(
                              ElementCollectorVisitor.getElements(dsc.getExpression(), true),
                              groups,
                              metadata,
                              null)
                          != null) {
                        found = true;
                        break;
                      }
                    }
                  }
                  if (!found) {
                    depAccessNode.setComplexQuery(true);
                  }
                }
              }
              processNode = depAccessNode;
              aNode = depAccessNode;
            }
            aNode.setShouldEvaluateExpressions(true);
          } else {

            // create access node
            aNode = new AccessNode(getID());
            processNode = aNode;
          }
          // -- special handling for system tables. currently they cannot perform projection
          try {
            if (command instanceof Query) {
              processNode = correctProjectionInternalTables(node, aNode);
            }
          } catch (QueryMetadataException err) {
            throw new TeiidComponentException(QueryPlugin.Event.TEIID30248, err);
          }
          setRoutingName(aNode, node, command);
          boolean shouldEval = false;
          if (command instanceof Insert) {
            Insert insert = (Insert) command;
            if (insert.getQueryExpression() != null) {
              insert.setQueryExpression(
                  (QueryCommand) aliasCommand(aNode, insert.getQueryExpression(), modelID));
            } else {
              for (int i = 0; i < insert.getValues().size(); i++) {
                Expression ex = (Expression) insert.getValues().get(i);
                if (!CriteriaCapabilityValidatorVisitor.canPushLanguageObject(
                    ex, modelID, metadata, capFinder, analysisRecord)) {
                  // replace with an expression symbol to let the rewriter know that it should be
                  // replaced
                  insert.getValues().set(i, new ExpressionSymbol("x", ex));
                  shouldEval = true;
                }
              }
            }
          } else if (command instanceof QueryCommand) {
            command = aliasCommand(aNode, command, modelID);
          }
          ev = EvaluatableVisitor.needsEvaluation(command, modelID, metadata, capFinder);
          aNode.setShouldEvaluateExpressions(
              ev.requiresEvaluation(EvaluationLevel.PROCESSING) || shouldEval);
          aNode.setCommand(command);
          Map<GroupSymbol, PlanNode> subPlans =
              (Map<GroupSymbol, PlanNode>) node.getProperty(Info.SUB_PLANS);

          // it makes more sense to allow the multisource affect to be elevated above just access
          // nodes
          if (aNode.getModelId() != null && metadata.isMultiSource(aNode.getModelId())) {
            VDBMetaData vdb = context.getVdb();
            aNode.setShouldEvaluateExpressions(true); // forces a rewrite
            aNode.setElements((List) node.getProperty(NodeConstants.Info.OUTPUT_COLS));
            if (node.hasBooleanProperty(Info.IS_MULTI_SOURCE)) {
              Expression ex = rewriteMultiSourceCommand(aNode.getCommand());
              aNode.setConnectorBindingExpression(ex);
              aNode.setMultiSource(true);
            } else {
              String sourceName = (String) node.getProperty(Info.SOURCE_NAME);
              aNode.setConnectorBindingExpression(new Constant(sourceName));
            }
          } else if (subPlans == null) {
            if (!aNode.isShouldEvaluate()) {
              aNode.minimizeProject(command);
            }
            // check if valid to share this with other nodes
            if (ev != null
                && ev.getDeterminismLevel().compareTo(Determinism.COMMAND_DETERMINISTIC) >= 0
                && command.areResultsCachable()) {
              checkForSharedSourceCommand(aNode);
            }
          }
          if (subPlans != null) {
            QueryCommand qc = (QueryCommand) command;
            if (qc.getWith() == null) {
              qc.setWith(new ArrayList<WithQueryCommand>(subPlans.size()));
            }
            Map<GroupSymbol, RelationalPlan> plans =
                new LinkedHashMap<GroupSymbol, RelationalPlan>();
            for (Map.Entry<GroupSymbol, PlanNode> entry : subPlans.entrySet()) {
              RelationalPlan subPlan = convert(entry.getValue());
              List<ElementSymbol> elems =
                  ResolverUtil.resolveElementsInGroup(entry.getKey(), metadata);
              subPlan.setOutputElements(elems);
              plans.put(entry.getKey(), subPlan);
              WithQueryCommand withQueryCommand = new WithQueryCommand(entry.getKey(), elems, null);
              qc.getWith().add(withQueryCommand);
            }
            aNode.setSubPlans(plans);
          }
        }
        break;

      case NodeConstants.Types.SELECT:
        Criteria crit = (Criteria) node.getProperty(NodeConstants.Info.SELECT_CRITERIA);
        if (!node.hasCollectionProperty(Info.OUTPUT_COLS)) {
          // the late optimization to create a dependent join from a subquery introduces
          // criteria that have no output elements set
          // TODO that should be cleaner, but the logic currently expects to be run after join
          // implementation
          // and rerunning assign output elements seems excessive
          node.setProperty(Info.OUTPUT_COLS, node.getFirstChild().getProperty(Info.OUTPUT_COLS));
        }
        SelectNode selnode = new SelectNode(getID());
        selnode.setCriteria(crit);
        // in case the parent was a source
        selnode.setProjectedExpressions(
            (List<Expression>) node.getProperty(NodeConstants.Info.PROJECT_COLS));
        processNode = selnode;

        break;

      case NodeConstants.Types.SORT:
      case NodeConstants.Types.DUP_REMOVE:
        if (node.getType() == NodeConstants.Types.DUP_REMOVE) {
          processNode = new DupRemoveNode(getID());
        } else {
          SortNode sortNode = new SortNode(getID());
          OrderBy orderBy = (OrderBy) node.getProperty(NodeConstants.Info.SORT_ORDER);
          if (orderBy != null) {
            sortNode.setSortElements(orderBy.getOrderByItems());
          }
          if (node.hasBooleanProperty(NodeConstants.Info.IS_DUP_REMOVAL)) {
            sortNode.setMode(Mode.DUP_REMOVE_SORT);
          }

          processNode = sortNode;
        }
        break;
      case NodeConstants.Types.GROUP:
        GroupingNode gnode = new GroupingNode(getID());
        gnode.setRollup(node.hasBooleanProperty(Info.ROLLUP));
        SymbolMap groupingMap = (SymbolMap) node.getProperty(NodeConstants.Info.SYMBOL_MAP);
        gnode.setOutputMapping(groupingMap);
        gnode.setRemoveDuplicates(node.hasBooleanProperty(NodeConstants.Info.IS_DUP_REMOVAL));
        List<Expression> gCols = (List) node.getProperty(NodeConstants.Info.GROUP_COLS);
        OrderBy orderBy = (OrderBy) node.getProperty(Info.SORT_ORDER);
        if (orderBy == null) {
          if (gCols != null) {
            LinkedHashSet<Expression> exprs = new LinkedHashSet<Expression>();
            for (Expression ex : gCols) {
              exprs.add(SymbolMap.getExpression(ex));
            }
            orderBy =
                new OrderBy(
                    RuleChooseJoinStrategy.createExpressionSymbols(
                        new ArrayList<Expression>(exprs)));
          }
        } else {
          HashSet<Expression> seen = new HashSet<Expression>();
          for (int i = 0; i < gCols.size(); i++) {
            if (i < orderBy.getOrderByItems().size()) {
              OrderByItem orderByItem = orderBy.getOrderByItems().get(i);
              Expression ex = SymbolMap.getExpression(orderByItem.getSymbol());
              if (!seen.add(ex)) {
                continue;
              }
              if (ex instanceof ElementSymbol) {
                ex = groupingMap.getMappedExpression((ElementSymbol) ex);
                orderByItem.setSymbol(new ExpressionSymbol("expr", ex)); // $NON-NLS-1$
              }
            } else {
              orderBy.addVariable(
                  new ExpressionSymbol("expr", gCols.get(i)), OrderBy.ASC); // $NON-NLS-1$
            }
          }
        }
        if (orderBy != null) {
          gnode.setOrderBy(orderBy.getOrderByItems());
        }
        processNode = gnode;
        break;

      case NodeConstants.Types.SOURCE:
        Object source = node.getProperty(NodeConstants.Info.TABLE_FUNCTION);
        if (source instanceof XMLTable) {
          XMLTable xt = (XMLTable) source;
          XMLTableNode xtn = new XMLTableNode(getID());
          // we handle the projection filtering once here rather than repeating the
          // path analysis on a per plan basis
          updateGroupName(node, xt);
          Map<Expression, Integer> elementMap =
              RelationalNode.createLookupMap(xt.getProjectedSymbols());
          List cols = (List) node.getProperty(NodeConstants.Info.OUTPUT_COLS);
          int[] projectionIndexes = RelationalNode.getProjectionIndexes(elementMap, cols);
          ArrayList<XMLColumn> filteredColumns = new ArrayList<XMLColumn>(projectionIndexes.length);
          for (int col : projectionIndexes) {
            filteredColumns.add(xt.getColumns().get(col));
          }
          xt.getXQueryExpression().useDocumentProjection(filteredColumns, analysisRecord);
          xtn.setProjectedColumns(filteredColumns);
          xtn.setTable(xt);
          processNode = xtn;
          break;
        }
        if (source instanceof ObjectTable) {
          ObjectTable ot = (ObjectTable) source;
          ObjectTableNode otn = new ObjectTableNode(getID());
          // we handle the projection filtering once here rather than repeating the
          // path analysis on a per plan basis
          updateGroupName(node, ot);
          Map<Expression, Integer> elementMap =
              RelationalNode.createLookupMap(ot.getProjectedSymbols());
          List<Expression> cols =
              (List<Expression>) node.getProperty(NodeConstants.Info.OUTPUT_COLS);
          int[] projectionIndexes = RelationalNode.getProjectionIndexes(elementMap, cols);
          ArrayList<ObjectColumn> filteredColumns =
              new ArrayList<ObjectColumn>(projectionIndexes.length);
          for (int col : projectionIndexes) {
            filteredColumns.add(ot.getColumns().get(col));
          }
          otn.setProjectedColumns(filteredColumns);
          otn.setTable(ot);
          processNode = otn;
          break;
        }
        if (source instanceof TextTable) {
          TextTableNode ttn = new TextTableNode(getID());
          TextTable tt = (TextTable) source;
          updateGroupName(node, tt);
          ttn.setTable(tt);
          processNode = ttn;
          break;
        }
        if (source instanceof ArrayTable) {
          ArrayTableNode atn = new ArrayTableNode(getID());
          ArrayTable at = (ArrayTable) source;
          updateGroupName(node, at);
          atn.setTable(at);
          processNode = atn;
          break;
        }
        SymbolMap symbolMap = (SymbolMap) node.getProperty(NodeConstants.Info.SYMBOL_MAP);
        if (symbolMap != null) {
          PlanNode child = node.getLastChild();

          if (child.getType() == NodeConstants.Types.PROJECT
              || child.getType() == NodeConstants.Types.SELECT) {
            // update the project cols based upon the original output
            child.setProperty(
                NodeConstants.Info.PROJECT_COLS, child.getProperty(NodeConstants.Info.OUTPUT_COLS));
          }
          child.setProperty(
              NodeConstants.Info.OUTPUT_COLS, node.getProperty(NodeConstants.Info.OUTPUT_COLS));
        }
        return null;
      case NodeConstants.Types.SET_OP:
        Operation setOp = (Operation) node.getProperty(NodeConstants.Info.SET_OPERATION);
        boolean useAll = ((Boolean) node.getProperty(NodeConstants.Info.USE_ALL)).booleanValue();
        if (setOp == Operation.UNION) {
          RelationalNode unionAllNode = new UnionAllNode(getID());

          if (useAll) {
            processNode = unionAllNode;
          } else {
            boolean onlyDupRemoval = node.hasBooleanProperty(NodeConstants.Info.IS_DUP_REMOVAL);
            if (onlyDupRemoval) {
              processNode = new DupRemoveNode(getID());
            } else {
              SortNode sNode = new SortNode(getID());
              sNode.setMode(Mode.DUP_REMOVE_SORT);
              processNode = sNode;
            }

            unionAllNode.setElements((List) node.getProperty(NodeConstants.Info.OUTPUT_COLS));
            processNode.addChild(unionAllNode);
          }
        } else {
          JoinNode joinAsSet = new JoinNode(getID());
          joinAsSet.setJoinStrategy(
              new MergeJoinStrategy(SortOption.SORT_DISTINCT, SortOption.SORT_DISTINCT, true));
          // If we push these sorts, we will have to enforce null order, since nulls are equal here
          List leftExpressions =
              (List) node.getFirstChild().getProperty(NodeConstants.Info.OUTPUT_COLS);
          List rightExpressions =
              (List) node.getLastChild().getProperty(NodeConstants.Info.OUTPUT_COLS);
          joinAsSet.setJoinType(
              setOp == Operation.EXCEPT ? JoinType.JOIN_ANTI_SEMI : JoinType.JOIN_SEMI);
          joinAsSet.setJoinExpressions(leftExpressions, rightExpressions);
          processNode = joinAsSet;
        }

        break;

      case NodeConstants.Types.TUPLE_LIMIT:
        Expression rowLimit = (Expression) node.getProperty(NodeConstants.Info.MAX_TUPLE_LIMIT);
        Expression offset = (Expression) node.getProperty(NodeConstants.Info.OFFSET_TUPLE_COUNT);
        LimitNode ln = new LimitNode(getID(), rowLimit, offset);
        ln.setImplicit(node.hasBooleanProperty(Info.IS_IMPLICIT_LIMIT));
        processNode = ln;
        break;

      case NodeConstants.Types.NULL:
        processNode = new NullNode(getID());
        break;

      default:
        throw new QueryPlannerException(
            QueryPlugin.Event.TEIID30250,
            QueryPlugin.Util.gs(
                QueryPlugin.Event.TEIID30250, NodeConstants.getNodeTypeString(node.getType())));
    }

    if (processNode != null) {
      processNode = prepareToAdd(node, processNode);
    }

    return processNode;
  }
Ejemplo n.º 2
0
  private PlanNode checkForProjectOptimization(
      PlanNode node,
      PlanNode root,
      QueryMetadataInterface metadata,
      CapabilitiesFinder capFinder,
      AnalysisRecord record,
      CommandContext context)
      throws QueryMetadataException, TeiidComponentException, QueryPlannerException {
    PlanNode projectNode = node.getFirstChild();
    PlanNode parent = node.getParent();
    boolean raiseAccess = false;
    // special check for unrelated order by compensation
    if (projectNode.getType() == NodeConstants.Types.ACCESS
        && RuleRaiseAccess.canRaiseOverSort(
            projectNode, metadata, capFinder, node, record, true, context)) {
      projectNode =
          NodeEditor.findNodePreOrder(
              projectNode,
              NodeConstants.Types.PROJECT,
              NodeConstants.Types.SOURCE | NodeConstants.Types.SET_OP);
      if (projectNode == null) {
        return root; // no interviening project
      }
      raiseAccess = true;
    } else if (projectNode.getType() == NodeConstants.Types.PROJECT
        && projectNode.getFirstChild() != null) {
      raiseAccess =
          projectNode.getFirstChild().getType() == NodeConstants.Types.ACCESS
              && RuleRaiseAccess.canRaiseOverSort(
                  projectNode.getFirstChild(), metadata, capFinder, node, record, false, context);

      // if we can't raise the access node and this doesn't have a limit, there's no point in
      // optimizing
      if (!raiseAccess && (parent == null || parent.getType() != NodeConstants.Types.TUPLE_LIMIT)) {
        return root;
      }
    } else {
      return root;
    }
    List<Expression> childOutputCols =
        (List<Expression>) projectNode.getFirstChild().getProperty(Info.OUTPUT_COLS);
    OrderBy orderBy = (OrderBy) node.getProperty(Info.SORT_ORDER);
    List<Expression> orderByKeys = orderBy.getSortKeys();
    LinkedHashSet<Expression> toProject = new LinkedHashSet();
    for (Expression ss : orderByKeys) {
      Expression original = ss;
      if (ss instanceof AliasSymbol) {
        ss = ((AliasSymbol) ss).getSymbol();
      }
      if (ss instanceof ExpressionSymbol) {
        if (!raiseAccess) {
          return root; // TODO: insert a new project node to handle this case
        }
      }
      if (!childOutputCols.contains(ss)) {
        if (!raiseAccess) {
          return root;
        }
        toProject.add(original);
      }
    }
    PlanNode toRepair = projectNode.getParent();
    if (!toProject.isEmpty()) {
      PlanNode intermediateProject = NodeFactory.getNewNode(NodeConstants.Types.PROJECT);
      toProject.addAll(childOutputCols);
      List<Expression> projectCols = new ArrayList<Expression>(toProject);
      childOutputCols = projectCols;
      intermediateProject.setProperty(NodeConstants.Info.PROJECT_COLS, projectCols);
      intermediateProject.setProperty(
          NodeConstants.Info.OUTPUT_COLS, new ArrayList<Expression>(projectCols));
      toRepair.getFirstChild().addAsParent(intermediateProject);
    }
    NodeEditor.removeChildNode(projectNode.getParent(), projectNode);
    if (parent != null
        && parent.getType() == NodeConstants.Types.TUPLE_LIMIT
        && parent.getParent() != null) {
      parent.addAsParent(projectNode);
    } else {
      if (parent == null) {
        root = projectNode;
      }
      if (parent != null && parent.getType() == NodeConstants.Types.TUPLE_LIMIT) {
        if (root == parent) {
          root = projectNode;
        }
        projectNode.addFirstChild(parent);
      } else {
        projectNode.addFirstChild(node);
      }
    }
    List<Expression> orderByOutputSymbols = (List<Expression>) node.getProperty(Info.OUTPUT_COLS);
    boolean unrelated = false;
    if (node.hasBooleanProperty(Info.UNRELATED_SORT)) {
      node.setProperty(Info.UNRELATED_SORT, false);
      unrelated = true;
    }
    for (OrderByItem item : orderBy.getOrderByItems()) {
      if (unrelated || !toProject.isEmpty()) {
        // update sort order
        int index = childOutputCols.indexOf(item.getSymbol());
        item.setExpressionPosition(index);
      }
      if (toProject.isEmpty()) {
        // strip alias as project was raised
        if (item.getSymbol() instanceof AliasSymbol) {
          item.setSymbol(((AliasSymbol) item.getSymbol()).getSymbol());
        }
      }
    }
    while (toRepair != node) {
      toRepair.setProperty(Info.OUTPUT_COLS, childOutputCols);
      toRepair = toRepair.getParent();
    }
    projectNode.setProperty(Info.OUTPUT_COLS, orderByOutputSymbols);
    projectNode.setProperty(Info.PROJECT_COLS, orderByOutputSymbols);
    node.setProperty(Info.OUTPUT_COLS, childOutputCols);
    if (parent != null) {
      parent.setProperty(Info.OUTPUT_COLS, childOutputCols);
    }
    if (raiseAccess) {
      PlanNode accessNode = NodeEditor.findNodePreOrder(node, NodeConstants.Types.ACCESS);

      // instead of just calling ruleraiseaccess, we're more selective
      // we do not want to raise the access node over a project that is handling an unrelated sort
      PlanNode newRoot =
          RuleRaiseAccess.raiseAccessNode(
              root, accessNode, metadata, capFinder, true, record, context);
      if (newRoot != null) {
        accessNode.setProperty(NodeConstants.Info.OUTPUT_COLS, childOutputCols);
        root = newRoot;
        if (!toProject.isEmpty()) {
          newRoot =
              RuleRaiseAccess.raiseAccessNode(
                  root, accessNode, metadata, capFinder, true, record, context);
        }
        if (newRoot != null) {
          root = newRoot;
          if (accessNode.getParent().getType() == NodeConstants.Types.TUPLE_LIMIT) {
            newRoot =
                RulePushLimit.raiseAccessOverLimit(
                    root, accessNode, metadata, capFinder, accessNode.getParent(), record);
          }
          if (newRoot != null) {
            root = newRoot;
          }
        }
      }
    }
    return root;
  }
 @Override
 public void visit(OrderByItem obj) {
   preVisitVisitor(obj);
   visitNode(obj.getSymbol());
   postVisitVisitor(obj);
 }