Block detected on EF Core 5 calls

[KungFuCookie]

Started using this over the passed few days to help me mitigate threadpool starvation in Azure.
What a wonderful package this is! - well done!

I am using a .Net Core (net5.0) with EF Core 5.0.1

I keep getting warnings when making a trip to database (where everything is async/await)

[12:40:12 WRN] Blocking method has been invoked and blocked, this can lead to threadpool starvation.
at System.Threading.WaitHandle.WaitOne(Int32 millisecondsTimeout)
at Microsoft.Data.SqlClient.TdsParser.CheckResetConnection(TdsParserStateObject stateObj)
at Microsoft.Data.SqlClient.TdsParserStateObject.WritePacket(Byte flushMode, Boolean canAccumulate)
at Microsoft.Data.SqlClient.TdsParserStateObject.WriteBytes(ReadOnlySpan1 b, Int32 len, Int32 offsetBuffer, Boolean canAccumulate, TaskCompletionSource1 completion, Byte[] array)
at Microsoft.Data.SqlClient.TdsParser.WriteString(String s, Int32 length, Int32 offset, TdsParserStateObject stateObj, Boolean canAccumulate)
at Microsoft.Data.SqlClient.TdsParser.WriteUnterminatedValue(Object value, MetaType type, Byte scale, Int32 actualLength, Int32 encodingByteSize, Int32 offset, TdsParserStateObject stateObj, Int32 paramSize, Boolean isDataFeed)
at Microsoft.Data.SqlClient.TdsParser.TDSExecuteRPCAddParameter(TdsParserStateObject stateObj, SqlParameter param, MetaType mt, Byte options)
at Microsoft.Data.SqlClient.TdsParser.TdsExecuteRPC(SqlCommand cmd, _SqlRPC[] rpcArray, Int32 timeout, Boolean inSchema, SqlNotificationRequest notificationRequest, TdsParserStateObject stateObj, Boolean isCommandProc, Boolean sync, TaskCompletionSource1 completion, Int32 startRpc, Int32 startParam) at Microsoft.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean isAsync, Int32 timeout, Task& task, Boolean asyncWrite, Boolean inRetry, SqlDataReader ds, Boolean describeParameterEncryptionRequest) at Microsoft.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, TaskCompletionSource1 completion, Int32 timeout, Task& task, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry, String method)
at Microsoft.Data.SqlClient.SqlCommand.BeginExecuteReaderInternal(CommandBehavior behavior, AsyncCallback callback, Object stateObject, Int32 timeout, Boolean inRetry, Boolean asyncWrite)
at Microsoft.Data.SqlClient.SqlCommand.BeginExecuteReaderAsync(CommandBehavior behavior, AsyncCallback callback, Object stateObject)
at Microsoft.Data.SqlClient.SqlCommand.<>c__DisplayClass173_0.b__0(CommandBehavior commandBehavior, AsyncCallback callback, Object stateObject)
at System.Threading.Tasks.TaskFactory1.FromAsyncImpl[TArg1](Func4 beginMethod, Func2 endFunction, Action1 endAction, TArg1 arg1, Object state, TaskCreationOptions creationOptions)
at System.Threading.Tasks.TaskFactory1.FromAsync[TArg1](Func4 beginMethod, Func2 endMethod, TArg1 arg1, Object state) at Microsoft.Data.SqlClient.SqlCommand.ExecuteReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken) at Microsoft.Data.SqlClient.SqlCommand.ExecuteDbDataReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReaderAsync(RelationalCommandParameterObject parameterObject, CancellationToken cancellationToken) at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine) at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReaderAsync(RelationalCommandParameterObject parameterObject, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable1.AsyncEnumerator.InitializeReaderAsync(DbContext _, Boolean result, CancellationToken cancellationToken)
at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable1.AsyncEnumerator.InitializeReaderAsync(DbContext _, Boolean result, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func4 operation, Func4 verifySucceeded, CancellationToken cancellationToken) at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine) at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func4 operation, Func4 verifySucceeded, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable1.AsyncEnumerator.MoveNextAsync()
at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable1.AsyncEnumerator.MoveNextAsync() at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.SingleAsync[TSource](IAsyncEnumerable1 asyncEnumerable, CancellationToken cancellationToken)
at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.SingleAsync[TSource](IAsyncEnumerable1 asyncEnumerable, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.ExecuteAsync[TResult](Expression query, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.ExecuteAsync[TResult](Expression expression, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ExecuteAsync[TSource,TResult](MethodInfo operatorMethodInfo, IQueryable1 source, Expression expression, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ExecuteAsync[TSource,TResult](MethodInfo operatorMethodInfo, IQueryable1 source, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.SingleAsync[TSource](IQueryable1 source, CancellationToken cancellationToken)
at Unified.DAL.Repositories.ScheduleRepository.GetByIdIncludeTicketsAndBookingFeeAsync(Int32 sessionId)

... the rest is ommitted for brevity

Would these be false flags?

[KungFuCookie]

public Task<Schedule> GetByIdIncludeTicketsAndBookingFeeAsync(int sessionId) { return Context.Schedules .Where(x => x.Id == sessionId) .Include(f => f.Film) .ThenInclude(mi => mi.MediaItems) .Include(f => f.Screen) .Include(c => c.Cinema) .ThenInclude(bf => bf.BookingFee) .Include(st => st.ScheduleTickets) .ThenInclude(t => t.Ticket) .SingleAsync(); }

[jrob]

I am seeing similar messages in a similar scenario. Not sure if they are true blocks or not.

[bcronje]

Same issue here. Is this a false positive?

[KungFuCookie]

I think it is... I had issue with my app under high load in Azure, after removing the problems, the only warnings raised by this package were EF Core calls, and my app has never fallen over since .... false positive I think.