示例#1
0
        //---------------------------------------------------------------------------------------
        // This invokes the entire query tree, invoking the per-element action for each result.
        //

        internal void RunSynchronously()
        {
            Debug.Assert(_elementAction != null);

            // Get the enumerator w/out using pipelining. By the time this returns, the query
            // has been executed and we are done. We expect the return to be null.
            Shared <bool> dummyTopLevelDisposeFlag = new Shared <bool>(false);

            CancellationTokenSource dummyInternalCancellationTokenSource = new CancellationTokenSource();

            // stuff in appropriate defaults for unspecified options.
            QuerySettings settingsWithDefaults = SpecifiedQuerySettings
                                                 .WithPerExecutionSettings(dummyInternalCancellationTokenSource, dummyTopLevelDisposeFlag)
                                                 .WithDefaults();

            QueryLifecycle.LogicalQueryExecutionBegin(settingsWithDefaults.QueryId);

            IEnumerator <TInput>?enumerator = GetOpenedEnumerator(ParallelMergeOptions.FullyBuffered, true, true,
                                                                  settingsWithDefaults);

            settingsWithDefaults.CleanStateAtQueryEnd();
            Debug.Assert(enumerator == null);

            QueryLifecycle.LogicalQueryExecutionEnd(settingsWithDefaults.QueryId);
        }
示例#2
0
        //---------------------------------------------------------------------------------------
        // Executes the query and returns the results in an array.
        //

        internal TOutput[] ExecuteAndGetResultsAsArray()
        {
            QuerySettings querySettings =
                SpecifiedQuerySettings
                .WithPerExecutionSettings()
                .WithDefaults();

            QueryLifecycle.LogicalQueryExecutionBegin(querySettings.QueryId);
            try
            {
                Debug.Assert(querySettings.ExecutionMode != null);
                if (querySettings.ExecutionMode.Value == ParallelExecutionMode.Default && LimitsParallelism)
                {
                    IEnumerable <TOutput> opSequential = AsSequentialQuery(querySettings.CancellationState.ExternalCancellationToken);
                    IEnumerable <TOutput> opSequentialWithCancelChecks = CancellableEnumerable.Wrap(opSequential, querySettings.CancellationState.ExternalCancellationToken);
                    return(ExceptionAggregator.WrapEnumerable(opSequentialWithCancelChecks, querySettings.CancellationState).ToArray());
                }

                QueryResults <TOutput> results = GetQueryResults(querySettings);

                // Top-level preemptive cancellation test.
                // This handles situations where cancellation has occurred before execution commences
                // The handling for in-execution occurs in QueryTaskGroupState.QueryEnd()

                if (querySettings.CancellationState.MergedCancellationToken.IsCancellationRequested)
                {
                    querySettings.CancellationState.ExternalCancellationToken.ThrowIfCancellationRequested();
                    throw new OperationCanceledException();
                }

                if (results.IsIndexible && OutputOrdered)
                {
                    // The special array-based merge performs better if the output is ordered, because
                    // it does not have to pay for ordering. In the unordered case, we it appears that
                    // the stop-and-go merge performs a little better.
                    ArrayMergeHelper <TOutput> merger = new ArrayMergeHelper <TOutput>(SpecifiedQuerySettings, results);
                    merger.Execute();
                    TOutput[] output = merger.GetResultsAsArray();
                    querySettings.CleanStateAtQueryEnd();
                    return(output);
                }
                else
                {
                    Debug.Assert(querySettings.TaskScheduler != null);
                    PartitionedStreamMerger <TOutput> merger =
                        new PartitionedStreamMerger <TOutput>(false, ParallelMergeOptions.FullyBuffered, querySettings.TaskScheduler,
                                                              OutputOrdered, querySettings.CancellationState, querySettings.QueryId);
                    results.GivePartitionedStream(merger);
                    Debug.Assert(merger.MergeExecutor != null);
                    TOutput[]? output = merger.MergeExecutor.GetResultsAsArray();
                    querySettings.CleanStateAtQueryEnd();
                    Debug.Assert(output != null);
                    return(output);
                }
            }
            finally
            {
                QueryLifecycle.LogicalQueryExecutionEnd(querySettings.QueryId);
            }
        }
示例#3
0
        //---------------------------------------------------------------------------------------
        // Executes the query and returns the results in an array.
        //

        internal TOutput[] ExecuteAndGetResultsAsArray()
        {
            QuerySettings querySettings =
                SpecifiedQuerySettings
                .WithPerExecutionSettings()
                .WithDefaults();

            QueryLifecycle.LogicalQueryExecutionBegin(querySettings.QueryId);
            try
            {
                if (querySettings.ExecutionMode.Value == ParallelExecutionMode.Default && LimitsParallelism)
                {
                    IEnumerable <TOutput> opSequential = AsSequentialQuery(querySettings.CancellationState.ExternalCancellationToken);
                    IEnumerable <TOutput> opSequentialWithCancelChecks = CancellableEnumerable.Wrap(opSequential, querySettings.CancellationState.ExternalCancellationToken);
                    return(ExceptionAggregator.WrapEnumerable(opSequentialWithCancelChecks, querySettings.CancellationState).ToArray());
                }

                QueryResults <TOutput> results = GetQueryResults(querySettings);

                if (results.IsIndexible && OutputOrdered)
                {
                    // The special array-based merge performs better if the output is ordered, because
                    // it does not have to pay for ordering. In the unordered case, we it appears that
                    // the stop-and-go merge performs a little better.
                    ArrayMergeHelper <TOutput> merger = new ArrayMergeHelper <TOutput>(SpecifiedQuerySettings, results);
                    merger.Execute();
                    TOutput[] output = merger.GetResultsAsArray();
                    querySettings.CleanStateAtQueryEnd();
                    return(output);
                }
                else
                {
                    PartitionedStreamMerger <TOutput> merger =
                        new PartitionedStreamMerger <TOutput>(false, ParallelMergeOptions.FullyBuffered, querySettings.TaskScheduler,
                                                              OutputOrdered, querySettings.CancellationState, querySettings.QueryId);
                    results.GivePartitionedStream(merger);
                    TOutput[] output = merger.MergeExecutor.GetResultsAsArray();
                    querySettings.CleanStateAtQueryEnd();
                    return(output);
                }
            }
            finally
            {
                QueryLifecycle.LogicalQueryExecutionEnd(querySettings.QueryId);
            }
        }