4

I'm encountering a deadlock when using asynchronous implementation of an EF Core provider.

Say I have the following models:

public class Player
{
    public string PlayerId { get; set;}

    public string Name { get; set;}

    public List<Game> Games { get; set;}
}

public class Game
{
    public string GameId { get; set; }

    public string PlayerId { get; set; }
    public Player Player { get; set;}
}

Now I want to run the following query:

ctx.Players
.Include(p => p.Games)
.Where(p => p.PlayerId == "123")
.Select(p => new {
    PlayerId = p.PlayerId,
    Games = p.Games.ToList()
}).ToListAsync();

When I run this code via Console Application/XUnit test it works as excepted... But when I run it via ASP.Net WebApi it get into deadlock and never ends...

I used ConfigureAwait(false) all the way down in order to prevent these kind of situations but it seems that the problematic code is down underneath. I think that it might be under the System.Interactive.Async library which EFCore use - To be more specific it is under: https://github.com/Reactive-Extensions/Rx.NET/blob/develop/Ix.NET/Source/System.Interactive.Async/ToAsyncEnumerable.cs#L72 there is a call to "Result" which actually blocks the execution thread.

Does anyone encountered this behavior, maybe there is some workaround?

Notice that if I don't load the "Games" entities then everything also works fine...

Edit: Added the StackTrace: (See the call to ToEnumerable)

Not Flagged 21672   5   Worker Thread   grpc 0 (cq 0) System.Interactive.Async.dll!System.Linq.AsyncEnumerable.**ToEnumerable_**<NG.Admin.BL.DAL.Entities.Game> Normal
mscorlib.dll!System.Threading.Monitor.Wait(object obj, int millisecondsTimeout, bool exitContext)
mscorlib.dll!System.Threading.Monitor.Wait(object obj, int millisecondsTimeout)
mscorlib.dll!System.Threading.ManualResetEventSlim.Wait(int millisecondsTimeout, System.Threading.CancellationToken cancellationToken)
mscorlib.dll!System.Threading.Tasks.Task.SpinThenBlockingWait(int millisecondsTimeout, System.Threading.CancellationToken cancellationToken)
mscorlib.dll!System.Threading.Tasks.Task.InternalWait(int millisecondsTimeout, System.Threading.CancellationToken cancellationToken)
mscorlib.dll!System.Threading.Tasks.Task.GetResultCore(bool waitCompletionNotification)
mscorlib.dll!System.Threading.Tasks.Task.Result.get()
System.Interactive.Async.dll!System.Linq.AsyncEnumerable.ToEnumerable_<NG.Admin.BL.DAL.Entities.Game>(System.Collections.Generic.IAsyncEnumerable<NG.Admin.BL.DAL.Entities.Game> source)
mscorlib.dll!System.Collections.Generic.List<NG.Admin.BL.DAL.Entities.Game>.List(System.Collections.Generic.IEnumerable<NG.Admin.BL.DAL.Entities.Game> collection)
System.Core.dll!System.Linq.Enumerable.ToList<NG.Admin.BL.DAL.Entities.Game>(System.Collections.Generic.IEnumerable<NG.Admin.BL.DAL.Entities.Game> source)
[Lightweight Function]
Microsoft.EntityFrameworkCore.dll!Microsoft.EntityFrameworkCore.Query.Internal.AsyncLinqOperatorProvider.SelectAsyncEnumerable<Microsoft.EntityFrameworkCore.Storage.ValueBuffer, NG.Admin.BL.Api.Player>.SelectAsyncEnumerator.MoveNext(System.Threading.CancellationToken cancellationToken)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task.TrySetResult(bool result)
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder.SetResult(bool result)
NG.Data.Spanner.EF.dll!NG.Data.Spanner.EF.Query.Internal.SpannerAsyncQueryingEnumerable<Microsoft.EntityFrameworkCore.Storage.ValueBuffer>.SpannerAsyncEnumerator.MoveNext(System.Threading.CancellationToken cancellationToken) Line 55
[Resuming Async Method]
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task.TrySetResult(bool result)
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder.SetResult(bool result)
Microsoft.EntityFrameworkCore.dll!Microsoft.EntityFrameworkCore.Query.Internal.AsyncLinqOperatorProvider.SelectAsyncEnumerable<Microsoft.EntityFrameworkCore.Storage.ValueBuffer, Microsoft.EntityFrameworkCore.Storage.ValueBuffer>.SelectAsyncEnumerator.MoveNext(System.Threading.CancellationToken cancellationToken)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task.TrySetResult(bool result)
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder.SetResult(bool result)
Microsoft.EntityFrameworkCore.Relational.dll!Microsoft.EntityFrameworkCore.Query.Internal.AsyncQueryingEnumerable.AsyncEnumerator.MoveNext(System.Threading.CancellationToken cancellationToken)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task.TrySetResult(bool result)
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder.SetResult(bool result)
Microsoft.EntityFrameworkCore.Relational.dll!Microsoft.EntityFrameworkCore.Query.Internal.AsyncQueryingEnumerable.AsyncEnumerator.BufferlessMoveNext(bool buffer, System.Threading.CancellationToken cancellationToken)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)
mscorlib.dll!System.Threading.Tasks.TaskCompletionSource<System.__Canon>.TrySetResult(System.__Canon result)
Microsoft.EntityFrameworkCore.Relational.dll!System.Threading.Tasks.TaskExtensions.Cast.AnonymousMethod__0(System.Threading.Tasks.Task t)
mscorlib.dll!System.Threading.Tasks.ContinuationTaskFromResultTask.InnerInvoke()
mscorlib.dll!System.Threading.Tasks.Task.Execute()
mscorlib.dll!System.Threading.Tasks.Task.ExecutionContextCallback(object obj)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.Tasks.Task.ExecuteWithThreadLocal(ref System.Threading.Tasks.Task currentTaskSlot)
mscorlib.dll!System.Threading.Tasks.Task.ExecuteEntry(bool bPreventDoubleExecution)
mscorlib.dll!System.Threading.Tasks.ThreadPoolTaskScheduler.TryExecuteTaskInline(System.Threading.Tasks.Task task, bool taskWasPreviouslyQueued)
mscorlib.dll!System.Threading.Tasks.TaskScheduler.TryRunInline(System.Threading.Tasks.Task task, bool taskWasPreviouslyQueued)
mscorlib.dll!System.Threading.Tasks.TaskContinuation.InlineIfPossibleOrElseQueue(System.Threading.Tasks.Task task, bool needsProtection)
mscorlib.dll!System.Threading.Tasks.StandardTaskContinuation.Run(System.Threading.Tasks.Task completedTask, bool bCanInlineContinuationTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder.SetResult(object result)
NG.Data.Spanner.EF.dll!NG.Data.Spanner.EF.Storage.Internal.SpannerRelationalCommand.ExecuteAsync(Microsoft.EntityFrameworkCore.Storage.IRelationalConnection connection, string executeMethod, System.Collections.Generic.IReadOnlyDictionary<string, object> parameterValues, bool closeConnection, System.Threading.CancellationToken cancellationToken) Line 41
[Resuming Async Method]
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder.SetResult(object result)
NG.Data.Spanner.EF.dll!NG.Data.Spanner.EF.Storage.Internal.SpannerRelationalCommand.ExecuteAsync(NG.Data.Spanner.EF.Storage.Internal.IOBehavior ioBehavior, Microsoft.EntityFrameworkCore.Storage.IRelationalConnection connection, string executeMethod, System.Collections.Generic.IReadOnlyDictionary<string, object> parameterValues, bool closeConnection, System.Threading.CancellationToken cancellationToken) Line 128
[Resuming Async Method]
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Data.Common.DbDataReader>.SetResult(System.Data.Common.DbDataReader result)
NG.Data.Spanner.dll!NG.Data.Spanner.SpannerCommand.ExecuteDbDataReaderAsync(System.Data.CommandBehavior behavior, System.Threading.CancellationToken cancellationToken) Line 67
[Resuming Async Method]
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<Google.Cloud.Spanner.V1.ResultSet>.SetResult(Google.Cloud.Spanner.V1.ResultSet result)
NG.Data.Spanner.dll!NG.Data.Spanner.SpannerConnection.RunQuery(string commandText) Line 118
[Resuming Async Method]
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<Google.Cloud.Spanner.V1.ResultSet>.SetResult(Google.Cloud.Spanner.V1.ResultSet result)
Google.Api.Gax.Grpc.dll!Google.Api.Gax.Grpc.ApiCallRetryExtensions.WithRetry.AnonymousMethod__0(Google.Cloud.Spanner.V1.ExecuteSqlRequest request, Google.Api.Gax.Grpc.CallSettings callSettings)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()
mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)
mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()
mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()
mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)
mscorlib.dll!System.Threading.Tasks.TaskCompletionSource<System.__Canon>.TrySetResult(System.__Canon result)
mscorlib.dll!System.Threading.Tasks.TaskCompletionSource<System.__Canon>.SetResult(System.__Canon result)
Grpc.Core.dll!Grpc.Core.Internal.AsyncCall<Google.Cloud.Spanner.V1.ExecuteSqlRequest, Google.Cloud.Spanner.V1.ResultSet>.HandleUnaryResponse(bool success, Grpc.Core.Internal.ClientSideStatus receivedStatus, byte[] receivedMessage, Grpc.Core.Metadata responseHeaders)
Grpc.Core.dll!Grpc.Core.Internal.CallSafeHandle.StartUnary.AnonymousMethod__0(bool success, Grpc.Core.Internal.BatchContextSafeHandle context)
Grpc.Core.dll!Grpc.Core.Internal.CompletionRegistry.HandleBatchCompletion(bool success, Grpc.Core.Internal.BatchContextSafeHandle ctx, Grpc.Core.Internal.BatchCompletionDelegate callback)
Grpc.Core.dll!Grpc.Core.Internal.CompletionRegistry.RegisterBatchCompletion.AnonymousMethod__0(bool success)
Grpc.Core.dll!Grpc.Core.Internal.GrpcThreadPool.RunHandlerLoop(Grpc.Core.Internal.CompletionQueueSafeHandle cq, Grpc.Core.Profiling.IProfiler optionalProfiler)
Grpc.Core.dll!Grpc.Core.Internal.GrpcThreadPool.CreateAndStartThread.AnonymousMethod__0()
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart_Context(object state)
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state)
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart()
4

2 回答 2

1

所以经过很长时间的调试后，我发现了问题并做了一些工作来解决它。我将尝试解释：

我正在为Google Spanner db构建EF Core 提供程序。为此，我使用的是Google Spanner DotNet API——尽管它尚未公开且非常不成熟的 API（实际上它只是自动生成的代码）。

此 API 使用 gRPC API，我看到的是，在使用此 API 的第一次异步调用中，使用了 gRPC 线程（gRPC 有自己的线程池实现）并将用于下一次执行调用 - 因为延续将仅在 gRPC 线程池中的该线程上运行。

EFCore 为使用 System.Interactive.Async 库的“游戏”列表调用 ToEnumerable。在 ToEnumerable 实现中，它实际上调用了“ Result ”，它阻塞了执行线程并等待结果。因为使用了 gRPC 线程并等待执行完成，所以我们遇到了死锁......

我的解决方法是使用以下代码：

GrpcEnvironment.SetCompletionQueueCount(1);

这样，允许继续在 gRPC 线程池中的其他线程上运行。

这只是一种解决方法，应该使用。但是，它有助于同时解决问题...

真正的解决方案可能应该在 System.Interactive.Async lib 的 EFCore 使用中，关于 ToEnumerable...（它应该是纯异步的）。

编辑： 如果它可能与任何人相关：刚刚发布了 Google Spanner 数据库的 EF Core 提供程序： https ://github.com/NoGame/NG.Data.Spanner

于 2017-04-19T13:21:14.223 回答
0

您的问题是您试图Games同步实现和异步实现投影对象。请注意以下事项：

.Select(p => new {
    PlayerId = p.PlayerId,
    Games = p.Games.ToList() // sync over async is blocking
}).ToListAsync();

您期望的工作（例如在常规 EF 中）是：

.Select(p => new {
    PlayerId = p.PlayerId,
    Games = p.Games // let the provider handle the enumeration materialization
}).ToListAsync();

但是根据您的评论，实际上并没有返回匿名投影对象上的游戏。看来，问题在于 EF Core 似乎不允许您摆脱幼稚的分配（您应该更新问题以表明这一点）。我想知道这是否与.Include()EF Core 中的工作方式无关。除了告诉您“原因”之外，我对 EF 的核心版本还不够熟悉，无法提供很多帮助，但本质上问题是您正在等待从等待基于该枚举实现的源获取枚举器。

于 2017-04-18T15:41:19.780 回答