Пример #1
0
 public SelectExprProcessorWDeliveryCallback(EventType eventType,
                                             BindProcessor bindProcessor,
                                             SelectExprProcessorDeliveryCallback selectExprProcessorCallback)
 {
     _eventType     = eventType;
     _bindProcessor = bindProcessor;
     _selectExprProcessorCallback = selectExprProcessorCallback;
 }
Пример #2
0
        /// <summary>
        /// Returns the processor to use for a given select-clause.
        /// </summary>
        /// <param name="assignedTypeNumberStack">The assigned type number stack.</param>
        /// <param name="selectionList">the list of select clause elements/items, which are expected to have been validated</param>
        /// <param name="isUsingWildcard">true if the wildcard (*) occurs in the select clause</param>
        /// <param name="insertIntoDesc">contains column names for the optional insert-into clause (if supplied)</param>
        /// <param name="optionalInsertIntoEventType">Type of the optional insert into event.</param>
        /// <param name="forClauseSpec">For clause spec.</param>
        /// <param name="typeService">serves stream type information</param>
        /// <param name="eventAdapterService">for generating wrapper instances for events</param>
        /// <param name="statementResultService">handles listeners/subscriptions awareness to reduce output result generation</param>
        /// <param name="valueAddEventService">service that handles update events and variant events</param>
        /// <param name="selectExprEventTypeRegistry">registry for event type to statements</param>
        /// <param name="engineImportService"></param>
        /// <param name="exprEvaluatorContext">context for expression evalauation</param>
        /// <param name="variableService">The variable service.</param>
        /// <param name="scriptingService">The scripting service.</param>
        /// <param name="tableService">The table service.</param>
        /// <param name="timeProvider">The time provider.</param>
        /// <param name="engineURI">The engine URI.</param>
        /// <param name="statementId">The statement identifier.</param>
        /// <param name="statementName">Name of the statement.</param>
        /// <param name="annotations">The annotations.</param>
        /// <param name="contextDescriptor">The context descriptor.</param>
        /// <param name="configuration">The configuration.</param>
        /// <param name="selectExprProcessorCallback">The select expr processor callback.</param>
        /// <param name="namedWindowMgmtService">The named window service.</param>
        /// <param name="intoTableClause">The into table clause.</param>
        /// <param name="groupByRollupInfo"></param>
        /// <param name="statementExtensionSvcContext"></param>
        /// <returns>
        /// select-clause expression processor
        /// </returns>
        /// <exception cref="ExprValidationException">Expected any of the  + Arrays.ToString(ForClauseKeyword.Values()).ToLowerCase() +  for-clause keywords after reserved keyword 'for'
        /// or
        /// The for-clause with the  + ForClauseKeyword.GROUPED_DELIVERY.Name +  keyword requires one or more grouping expressions
        /// or
        /// The for-clause with the  + ForClauseKeyword.DISCRETE_DELIVERY.Name +  keyword does not allow grouping expressions
        /// or
        /// The for-clause with delivery keywords may only occur once in a statement
        /// or
        /// Expected any of the  + Arrays.ToString(ForClauseKeyword.Values()).ToLowerCase() +  for-clause keywords after reserved keyword 'for'</exception>
        /// <throws>ExprValidationException to indicate the select expression cannot be validated</throws>
        public static SelectExprProcessor GetProcessor(
            ICollection <int> assignedTypeNumberStack,
            SelectClauseElementCompiled[] selectionList,
            bool isUsingWildcard,
            InsertIntoDesc insertIntoDesc,
            EventType optionalInsertIntoEventType,
            ForClauseSpec forClauseSpec,
            StreamTypeService typeService,
            EventAdapterService eventAdapterService,
            StatementResultService statementResultService,
            ValueAddEventService valueAddEventService,
            SelectExprEventTypeRegistry selectExprEventTypeRegistry,
            EngineImportService engineImportService,
            ExprEvaluatorContext exprEvaluatorContext,
            VariableService variableService,
            ScriptingService scriptingService,
            TableService tableService,
            TimeProvider timeProvider,
            string engineURI,
            int statementId,
            string statementName,
            Attribute[] annotations,
            ContextDescriptor contextDescriptor,
            ConfigurationInformation configuration,
            SelectExprProcessorDeliveryCallback selectExprProcessorCallback,
            NamedWindowMgmtService namedWindowMgmtService,
            IntoTableSpec intoTableClause,
            GroupByRollupInfo groupByRollupInfo,
            StatementExtensionSvcContext statementExtensionSvcContext)
        {
            if (selectExprProcessorCallback != null)
            {
                var bindProcessor = new BindProcessor(selectionList, typeService.EventTypes, typeService.StreamNames, tableService);
                IDictionary <string, object> properties = new LinkedHashMap <string, object>();
                for (var i = 0; i < bindProcessor.ColumnNamesAssigned.Length; i++)
                {
                    properties.Put(bindProcessor.ColumnNamesAssigned[i], bindProcessor.ExpressionTypes[i]);
                }
                var eventType = eventAdapterService.CreateAnonymousObjectArrayType("Output_" + statementName, properties);
                return(new SelectExprProcessorWDeliveryCallback(eventType, bindProcessor, selectExprProcessorCallback));
            }

            var synthetic = GetProcessorInternal(
                assignedTypeNumberStack, selectionList, isUsingWildcard, insertIntoDesc, optionalInsertIntoEventType,
                typeService, eventAdapterService, valueAddEventService, selectExprEventTypeRegistry,
                engineImportService, statementId, statementName, annotations, configuration, namedWindowMgmtService, tableService,
                groupByRollupInfo);

            // Handle table as an optional service
            if (statementResultService != null)
            {
                // Handle for-clause delivery contract checking
                ExprNode[] groupedDeliveryExpr = null;
                var        forDelivery         = false;
                if (forClauseSpec != null)
                {
                    foreach (var item in forClauseSpec.Clauses)
                    {
                        if (item.Keyword == null)
                        {
                            throw new ExprValidationException("Expected any of the " + EnumHelper.GetValues <ForClauseKeyword>().Render().ToLower() + " for-clause keywords after reserved keyword 'for'");
                        }
                        try
                        {
                            ForClauseKeyword keyword = EnumHelper.Parse <ForClauseKeyword>(item.Keyword);
                            if ((keyword == ForClauseKeyword.GROUPED_DELIVERY) && (item.Expressions.IsEmpty()))
                            {
                                throw new ExprValidationException(
                                          "The for-clause with the " + ForClauseKeyword.GROUPED_DELIVERY.GetName() +
                                          " keyword requires one or more grouping expressions");
                            }
                            if ((keyword == ForClauseKeyword.DISCRETE_DELIVERY) && (!item.Expressions.IsEmpty()))
                            {
                                throw new ExprValidationException(
                                          "The for-clause with the " + ForClauseKeyword.DISCRETE_DELIVERY.GetName() +
                                          " keyword does not allow grouping expressions");
                            }
                            if (forDelivery)
                            {
                                throw new ExprValidationException(
                                          "The for-clause with delivery keywords may only occur once in a statement");
                            }
                        }
                        catch (ExprValidationException)
                        {
                            throw;
                        }
                        catch (EPException)
                        {
                            throw;
                        }
                        catch (Exception ex)
                        {
                            throw new ExprValidationException("Expected any of the " + EnumHelper.GetValues <ForClauseKeyword>().Render().ToLower() + " for-clause keywords after reserved keyword 'for'", ex);
                        }

                        StreamTypeService type = new StreamTypeServiceImpl(synthetic.ResultEventType, null, false, engineURI);
                        groupedDeliveryExpr = new ExprNode[item.Expressions.Count];
                        var validationContext = new ExprValidationContext(type, engineImportService, statementExtensionSvcContext, null, timeProvider, variableService, tableService, exprEvaluatorContext, eventAdapterService, statementName, statementId, annotations, null, scriptingService, false, false, true, false, intoTableClause == null ? null : intoTableClause.Name, false);  // no context descriptor available
                        for (var i = 0; i < item.Expressions.Count; i++)
                        {
                            groupedDeliveryExpr[i] = ExprNodeUtility.GetValidatedSubtree(ExprNodeOrigin.FORCLAUSE, item.Expressions[i], validationContext);
                        }
                        forDelivery = true;
                    }
                }

                var bindProcessor = new BindProcessor(selectionList, typeService.EventTypes, typeService.StreamNames, tableService);
                statementResultService.SetSelectClause(bindProcessor.ExpressionTypes, bindProcessor.ColumnNamesAssigned, forDelivery, ExprNodeUtility.GetEvaluators(groupedDeliveryExpr), exprEvaluatorContext);
                return(new SelectExprResultProcessor(statementResultService, synthetic, bindProcessor));
            }

            return(synthetic);
        }
        public static EPStatementStartMethodSelectDesc Prepare(
            StatementSpecCompiled statementSpec,
            EPServicesContext services,
            StatementContext statementContext,
            bool recoveringResilient,
            AgentInstanceContext defaultAgentInstanceContext,
            bool queryPlanLogging,
            ViewableActivatorFactory optionalViewableActivatorFactory,
            OutputProcessViewCallback optionalOutputProcessViewCallback,
            SelectExprProcessorDeliveryCallback selectExprProcessorDeliveryCallback)
        {
            // define stop and destroy
            var stopCallbacks    = new List <StopCallback>();
            var destroyCallbacks = new EPStatementDestroyCallbackList();

            // determine context
            var contextName             = statementSpec.OptionalContextName;
            var contextPropertyRegistry = (contextName != null) ? services.ContextManagementService.GetContextDescriptor(contextName).ContextPropertyRegistry : null;

            // Determine stream names for each stream - some streams may not have a name given
            var streamNames = EPStatementStartMethodHelperUtil.DetermineStreamNames(statementSpec.StreamSpecs);
            var numStreams  = streamNames.Length;

            if (numStreams == 0)
            {
                throw new ExprValidationException("The from-clause is required but has not been specified");
            }
            var isJoin     = statementSpec.StreamSpecs.Length > 1;
            var hasContext = statementSpec.OptionalContextName != null;

            // First we create streams for subselects, if there are any
            var subSelectStreamDesc = EPStatementStartMethodHelperSubselect.CreateSubSelectActivation(services, statementSpec, statementContext, destroyCallbacks);

            // Create streams and views
            var eventStreamParentViewableActivators = new ViewableActivator[numStreams];
            var unmaterializedViewChain             = new ViewFactoryChain[numStreams];
            var eventTypeNames           = new string[numStreams];
            var isNamedWindow            = new bool[numStreams];
            var historicalEventViewables = new HistoricalEventViewable[numStreams];

            // verify for joins that required views are present
            var joinAnalysisResult   = VerifyJoinViews(statementSpec, statementContext.NamedWindowMgmtService, defaultAgentInstanceContext);
            var evaluatorContextStmt = new ExprEvaluatorContextStatement(statementContext, false);

            for (var i = 0; i < statementSpec.StreamSpecs.Length; i++)
            {
                var streamSpec = statementSpec.StreamSpecs[i];

                var isCanIterateUnbound = streamSpec.ViewSpecs.Length == 0 &&
                                          (services.ConfigSnapshot.EngineDefaults.ViewResourcesConfig.IsIterableUnbound ||
                                           AnnotationUtil.FindAttribute(statementSpec.Annotations, typeof(IterableUnboundAttribute)) != null);

                // Create view factories and parent view based on a filter specification
                if (streamSpec is FilterStreamSpecCompiled)
                {
                    var filterStreamSpec = (FilterStreamSpecCompiled)streamSpec;
                    eventTypeNames[i] = filterStreamSpec.FilterSpec.FilterForEventTypeName;

                    // Since only for non-joins we get the existing stream's lock and try to reuse it's views
                    var filterSubselectSameStream = EPStatementStartMethodHelperUtil.DetermineSubquerySameStream(statementSpec, filterStreamSpec);

                    // create activator
                    ViewableActivator activatorDeactivator;
                    if (optionalViewableActivatorFactory != null)
                    {
                        activatorDeactivator = optionalViewableActivatorFactory.CreateActivatorSimple(filterStreamSpec);
                        if (activatorDeactivator == null)
                        {
                            throw new IllegalStateException("Viewable activate is null for " + filterStreamSpec.FilterSpec.FilterForEventType.Name);
                        }
                    }
                    else
                    {
                        if (!hasContext)
                        {
                            activatorDeactivator = services.ViewableActivatorFactory.CreateStreamReuseView(services, statementContext, statementSpec, filterStreamSpec, isJoin, evaluatorContextStmt, filterSubselectSameStream, i, isCanIterateUnbound);
                        }
                        else
                        {
                            InstrumentationAgent instrumentationAgentFilter = null;
                            if (InstrumentationHelper.ENABLED)
                            {
                                var eventTypeName = filterStreamSpec.FilterSpec.FilterForEventType.Name;
                                var streamNumber  = i;
                                instrumentationAgentFilter = new ProxyInstrumentationAgent()
                                {
                                    ProcIndicateQ = () => {
                                        InstrumentationHelper.Get().QFilterActivationStream(eventTypeName, streamNumber);
                                    },
                                    ProcIndicateA = () => {
                                        InstrumentationHelper.Get().AFilterActivationStream();
                                    },
                                };
                            }

                            activatorDeactivator = services.ViewableActivatorFactory.CreateFilterProxy(services, filterStreamSpec.FilterSpec, statementSpec.Annotations, false, instrumentationAgentFilter, isCanIterateUnbound, i);
                        }
                    }
                    eventStreamParentViewableActivators[i] = activatorDeactivator;

                    var resultEventType = filterStreamSpec.FilterSpec.ResultEventType;
                    unmaterializedViewChain[i] = services.ViewService.CreateFactories(i, resultEventType, streamSpec.ViewSpecs, streamSpec.Options, statementContext, false, -1);
                }
                // Create view factories and parent view based on a pattern expression
                else if (streamSpec is PatternStreamSpecCompiled)
                {
                    var patternStreamSpec = (PatternStreamSpecCompiled)streamSpec;
                    var usedByChildViews  = streamSpec.ViewSpecs.Length > 0 || (statementSpec.InsertIntoDesc != null);
                    var patternTypeName   = statementContext.StatementId + "_pattern_" + i;
                    var eventType         = services.EventAdapterService.CreateSemiAnonymousMapType(patternTypeName, patternStreamSpec.TaggedEventTypes, patternStreamSpec.ArrayEventTypes, usedByChildViews);
                    unmaterializedViewChain[i] = services.ViewService.CreateFactories(i, eventType, streamSpec.ViewSpecs, streamSpec.Options, statementContext, false, -1);

                    var rootFactoryNode = services.PatternNodeFactory.MakeRootNode(patternStreamSpec.EvalFactoryNode);
                    var patternContext  = statementContext.PatternContextFactory.CreateContext(statementContext, i, rootFactoryNode, patternStreamSpec.MatchedEventMapMeta, true);

                    // create activator
                    var patternActivator = services.ViewableActivatorFactory.CreatePattern(patternContext, rootFactoryNode, eventType, EPStatementStartMethodHelperUtil.IsConsumingFilters(patternStreamSpec.EvalFactoryNode), patternStreamSpec.IsSuppressSameEventMatches, patternStreamSpec.IsDiscardPartialsOnMatch, isCanIterateUnbound);
                    eventStreamParentViewableActivators[i] = patternActivator;
                }
                // Create view factories and parent view based on a database SQL statement
                else if (streamSpec is DBStatementStreamSpec)
                {
                    ValidateNoViews(streamSpec, "Historical data");
                    var sqlStreamSpec                  = (DBStatementStreamSpec)streamSpec;
                    var typeConversionHook             = (SQLColumnTypeConversion)TypeHelper.GetAnnotationHook(statementSpec.Annotations, HookType.SQLCOL, typeof(SQLColumnTypeConversion), statementContext.MethodResolutionService);
                    var outputRowConversionHook        = (SQLOutputRowConversion)TypeHelper.GetAnnotationHook(statementSpec.Annotations, HookType.SQLROW, typeof(SQLOutputRowConversion), statementContext.MethodResolutionService);
                    var epStatementAgentInstanceHandle = defaultAgentInstanceContext.EpStatementAgentInstanceHandle;
                    var historicalEventViewable        = DatabasePollingViewableFactory.CreateDBStatementView(
                        statementContext.StatementId, i, sqlStreamSpec,
                        services.DatabaseRefService,
                        services.EventAdapterService,
                        epStatementAgentInstanceHandle,
                        statementContext.Annotations,
                        typeConversionHook,
                        outputRowConversionHook,
                        statementContext.ConfigSnapshot.EngineDefaults.LoggingConfig.IsEnableADO,
                        services.DataCacheFactory,
                        statementContext);
                    historicalEventViewables[i]            = historicalEventViewable;
                    unmaterializedViewChain[i]             = ViewFactoryChain.FromTypeNoViews(historicalEventViewable.EventType);
                    eventStreamParentViewableActivators[i] = services.ViewableActivatorFactory.MakeHistorical(historicalEventViewable);
                    stopCallbacks.Add(historicalEventViewable);
                }
                else if (streamSpec is MethodStreamSpec)
                {
                    ValidateNoViews(streamSpec, "Method data");
                    var methodStreamSpec = (MethodStreamSpec)streamSpec;
                    var epStatementAgentInstanceHandle = defaultAgentInstanceContext.EpStatementAgentInstanceHandle;
                    var historicalEventViewable        = MethodPollingViewableFactory.CreatePollMethodView(
                        i, methodStreamSpec, services.EventAdapterService, epStatementAgentInstanceHandle,
                        statementContext.MethodResolutionService, services.EngineImportService,
                        statementContext.SchedulingService, statementContext.ScheduleBucket, evaluatorContextStmt,
                        statementContext.VariableService, statementContext.ContextName, services.DataCacheFactory,
                        statementContext);
                    historicalEventViewables[i]            = historicalEventViewable;
                    unmaterializedViewChain[i]             = ViewFactoryChain.FromTypeNoViews(historicalEventViewable.EventType);
                    eventStreamParentViewableActivators[i] = services.ViewableActivatorFactory.MakeHistorical(historicalEventViewable);
                    stopCallbacks.Add(historicalEventViewable);
                }
                else if (streamSpec is TableQueryStreamSpec)
                {
                    ValidateNoViews(streamSpec, "Table data");
                    var tableStreamSpec = (TableQueryStreamSpec)streamSpec;
                    if (isJoin && tableStreamSpec.FilterExpressions.Count > 0)
                    {
                        throw new ExprValidationException("Joins with tables do not allow table filter expressions, please add table filters to the where-clause instead");
                    }
                    var             metadata         = services.TableService.GetTableMetadata(tableStreamSpec.TableName);
                    ExprEvaluator[] tableFilterEvals = null;
                    if (tableStreamSpec.FilterExpressions.Count > 0)
                    {
                        tableFilterEvals = ExprNodeUtility.GetEvaluators(tableStreamSpec.FilterExpressions);
                    }
                    EPLValidationUtil.ValidateContextName(true, metadata.TableName, metadata.ContextName, statementSpec.OptionalContextName, false);
                    eventStreamParentViewableActivators[i] = services.ViewableActivatorFactory.CreateTable(metadata, tableFilterEvals);
                    unmaterializedViewChain[i]             = ViewFactoryChain.FromTypeNoViews(metadata.InternalEventType);
                    eventTypeNames[i] = tableStreamSpec.TableName;
                    joinAnalysisResult.SetTablesForStream(i, metadata);
                    if (tableStreamSpec.Options.IsUnidirectional)
                    {
                        throw new ExprValidationException("Tables cannot be marked as unidirectional");
                    }
                    if (tableStreamSpec.Options.IsRetainIntersection || tableStreamSpec.Options.IsRetainUnion)
                    {
                        throw new ExprValidationException("Tables cannot be marked with retain");
                    }
                    if (isJoin)
                    {
                        destroyCallbacks.AddCallback(new EPStatementDestroyCallbackTableIdxRef(services.TableService, metadata, statementContext.StatementName));
                    }
                    services.StatementVariableRefService.AddReferences(statementContext.StatementName, metadata.TableName);
                }
                else if (streamSpec is NamedWindowConsumerStreamSpec)
                {
                    var namedSpec       = (NamedWindowConsumerStreamSpec)streamSpec;
                    var processor       = services.NamedWindowMgmtService.GetProcessor(namedSpec.WindowName);
                    var namedWindowType = processor.TailView.EventType;
                    if (namedSpec.OptPropertyEvaluator != null)
                    {
                        namedWindowType = namedSpec.OptPropertyEvaluator.FragmentEventType;
                    }

                    eventStreamParentViewableActivators[i] = services.ViewableActivatorFactory.CreateNamedWindow(processor, namedSpec, statementContext);
                    services.NamedWindowConsumerMgmtService.AddConsumer(statementContext, namedSpec);
                    unmaterializedViewChain[i] = services.ViewService.CreateFactories(i, namedWindowType, namedSpec.ViewSpecs, namedSpec.Options, statementContext, false, -1);
                    joinAnalysisResult.SetNamedWindow(i);
                    eventTypeNames[i] = namedSpec.WindowName;
                    isNamedWindow[i]  = true;

                    // Consumers to named windows cannot declare a data window view onto the named window to avoid duplicate remove streams
                    EPStatementStartMethodHelperValidate.ValidateNoDataWindowOnNamedWindow(unmaterializedViewChain[i].FactoryChain);
                }
                else
                {
                    throw new ExprValidationException("Unknown stream specification type: " + streamSpec);
                }
            }

            // handle match-recognize pattern
            if (statementSpec.MatchRecognizeSpec != null)
            {
                if (isJoin)
                {
                    throw new ExprValidationException("Joins are not allowed when using match-recognize");
                }
                if (joinAnalysisResult.TablesPerStream[0] != null)
                {
                    throw new ExprValidationException("Tables cannot be used with match-recognize");
                }
                var isUnbound = (unmaterializedViewChain[0].FactoryChain.IsEmpty()) && (!(statementSpec.StreamSpecs[0] is NamedWindowConsumerStreamSpec));
                var factoryX  = services.RegexHandlerFactory.MakeViewFactory(unmaterializedViewChain[0], statementSpec.MatchRecognizeSpec, defaultAgentInstanceContext, isUnbound, statementSpec.Annotations, services.ConfigSnapshot.EngineDefaults.MatchRecognizeConfig);
                unmaterializedViewChain[0].FactoryChain.Add(factoryX);

                EPStatementStartMethodHelperAssignExpr.AssignAggregations(factoryX.AggregationService, factoryX.AggregationExpressions);
            }

            // Obtain event types from view factory chains
            var streamEventTypes = new EventType[statementSpec.StreamSpecs.Length];

            for (var i = 0; i < unmaterializedViewChain.Length; i++)
            {
                streamEventTypes[i] = unmaterializedViewChain[i].EventType;
            }

            // Add uniqueness information useful for joins
            joinAnalysisResult.AddUniquenessInfo(unmaterializedViewChain, statementSpec.Annotations);

            // Validate sub-select views
            var subSelectStrategyCollection = EPStatementStartMethodHelperSubselect.PlanSubSelect(services, statementContext, queryPlanLogging, subSelectStreamDesc, streamNames, streamEventTypes, eventTypeNames, statementSpec.DeclaredExpressions, contextPropertyRegistry);

            // Construct type information per stream
            StreamTypeService typeService      = new StreamTypeServiceImpl(streamEventTypes, streamNames, EPStatementStartMethodHelperUtil.GetHasIStreamOnly(isNamedWindow, unmaterializedViewChain), services.EngineURI, false);
            var viewResourceDelegateUnverified = new ViewResourceDelegateUnverified();

            // Validate views that require validation, specifically streams that don't have
            // sub-views such as DB SQL joins
            var historicalViewableDesc = new HistoricalViewableDesc(numStreams);

            for (var stream = 0; stream < historicalEventViewables.Length; stream++)
            {
                var historicalEventViewable = historicalEventViewables[stream];
                if (historicalEventViewable == null)
                {
                    continue;
                }
                historicalEventViewable.Validate(
                    services.EngineImportService,
                    typeService,
                    statementContext.MethodResolutionService,
                    statementContext.TimeProvider,
                    statementContext.VariableService, statementContext.TableService,
                    statementContext.ScriptingService, evaluatorContextStmt,
                    services.ConfigSnapshot, services.SchedulingService, services.EngineURI,
                    statementSpec.SqlParameters,
                    statementContext.EventAdapterService, statementContext);
                historicalViewableDesc.SetHistorical(stream, historicalEventViewable.RequiredStreams);
                if (historicalEventViewable.RequiredStreams.Contains(stream))
                {
                    throw new ExprValidationException("Parameters for historical stream " + stream + " indicate that the stream is subordinate to itself as stream parameters originate in the same stream");
                }
            }

            // unidirectional is not supported with into-table
            if (joinAnalysisResult.IsUnidirectional && statementSpec.IntoTableSpec != null)
            {
                throw new ExprValidationException("Into-table does not allow unidirectional joins");
            }

            // Construct a processor for results posted by views and joins, which takes care of aggregation if required.
            // May return null if we don't need to post-process results posted by views or joins.
            var resultSetProcessorPrototypeDesc = ResultSetProcessorFactoryFactory.GetProcessorPrototype(
                statementSpec, statementContext, typeService, viewResourceDelegateUnverified, joinAnalysisResult.UnidirectionalInd, true, contextPropertyRegistry, selectExprProcessorDeliveryCallback, services.ConfigSnapshot, services.ResultSetProcessorHelperFactory, false, false);

            // Validate where-clause filter tree, outer join clause and output limit expression
            EPStatementStartMethodHelperValidate.ValidateNodes(statementSpec, statementContext, typeService, viewResourceDelegateUnverified);

            // Handle 'prior' function nodes in terms of view requirements
            var viewResourceDelegateVerified = EPStatementStartMethodHelperViewResources.VerifyPreviousAndPriorRequirements(unmaterializedViewChain, viewResourceDelegateUnverified);

            // handle join
            JoinSetComposerPrototype joinSetComposerPrototype = null;

            if (numStreams > 1)
            {
                var selectsRemoveStream =
                    statementSpec.SelectStreamSelectorEnum.IsSelectsRStream() ||
                    statementSpec.OutputLimitSpec != null;
                var hasAggregations = !resultSetProcessorPrototypeDesc.AggregationServiceFactoryDesc.Expressions.IsEmpty();
                joinSetComposerPrototype = JoinSetComposerPrototypeFactory.MakeComposerPrototype(
                    statementContext.StatementName, statementContext.StatementId,
                    statementSpec.OuterJoinDescList, statementSpec.FilterRootNode, typeService.EventTypes, streamNames,
                    joinAnalysisResult, queryPlanLogging, statementContext, historicalViewableDesc, defaultAgentInstanceContext,
                    selectsRemoveStream, hasAggregations, services.TableService, false, services.EventTableIndexService.AllowInitIndex(recoveringResilient));
            }

            // obtain factory for output limiting
            var outputViewFactory = OutputProcessViewFactoryFactory.Make(statementSpec, services.InternalEventRouter, statementContext, resultSetProcessorPrototypeDesc.ResultSetProcessorFactory.ResultEventType, optionalOutputProcessViewCallback, services.TableService, resultSetProcessorPrototypeDesc.ResultSetProcessorFactory.ResultSetProcessorType, services.ResultSetProcessorHelperFactory, services.StatementVariableRefService);

            // Factory for statement-context instances
            var factory = new StatementAgentInstanceFactorySelect(
                numStreams, eventStreamParentViewableActivators,
                statementContext, statementSpec, services,
                typeService, unmaterializedViewChain, resultSetProcessorPrototypeDesc, joinAnalysisResult, recoveringResilient,
                joinSetComposerPrototype, subSelectStrategyCollection, viewResourceDelegateVerified, outputViewFactory);

            EPStatementStopMethod stopMethod = new EPStatementStopMethodImpl(statementContext, stopCallbacks);

            return(new EPStatementStartMethodSelectDesc(factory, subSelectStrategyCollection, viewResourceDelegateUnverified, resultSetProcessorPrototypeDesc, stopMethod, destroyCallbacks));
        }