SqlConnection reuse / MultipleActiveResultSets=true

Hi,

When a new User is created via /userAccess/UserRegistrations, the handlers in other modules which are subscribed to NewUserRegisteredIntegrationEvent throw the error below. The issue seems to be related toSELECT/UPDATE statements performed using Dapper in inbox processing (ProcessInboxCommandHandler) and reusing the sql connection.

[19:09:45 INF] [UserAccess] [OutboxMessage:cd855ef7-de09-491b-93a1-8e22e426bc8f] Publishing CompanyName.MyMeetings.Modules.UserAccess.IntegrationEvents.NewUserRegisteredIntegrationEvent
[19:09:46 ERR] [Payments] [] Job DEFAULT.a5b45b20-44cf-4cda-9334-d412a7af9b9b threw an unhandled Exception:
System.InvalidOperationException: The connection does not support MultipleActiveResultSets.
   at System.Data.SqlClient.SqlInternalConnectionTds.ValidateConnectionForExecute(SqlCommand command)
   at System.Data.SqlClient.SqlCommand.ValidateCommand(Boolean async, String method)
   at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, Boolean sendToPipe, Int32 timeout, Boolean asyncWrite, String methodName)
   at System.Data.SqlClient.SqlCommand.BeginExecuteNonQuery(AsyncCallback callback, Object stateObject)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncImpl(Func`3 beginMethod, Func`2 endFunction, Action`1 endAction, Object state, TaskCreationOptions creationOptions)
   at System.Threading.Tasks.TaskFactory`1.FromAsync(Func`3 beginMethod, Func`2 endMethod, Object state)
   at System.Data.SqlClient.SqlCommand.ExecuteNonQueryAsync(CancellationToken cancellationToken)
--- End of stack trace from previous location where exception was thrown ---
   at Dapper.SqlMapper.ExecuteImplAsync(IDbConnection cnn, CommandDefinition command, Object param) in C:\projects\dapper\Dapper\SqlMapper.Async.cs:line 678
   at CompanyName.MyMeetings.Modules.Administration.Infrastructure.Configuration.Processing.Inbox.ProcessInboxCommandHandler.Handle(ProcessInboxCommand command, CancellationToken cancellationToken) in C:\Projects\dev\dotnet\tests\modular-monolith-with-ddd\src\Modules\Administration\Infrastructure\Configuration\Processing\Inbox\ProcessInboxCommandHandler.cs:line 60
   at CompanyName.MyMeetings.Modules.Administration.Infrastructure.Configuration.Processing.UnitOfWorkCommandHandlerWithResultDecorator`2.Handle(T command, CancellationToken cancellationToken) in C:\Projects\dev\dotnet\tests\modular-monolith-with-ddd\src\Modules\Administration\Infrastructure\Configuration\Processing\UnitOfWorkCommandHandlerWithResultDecorator.cs:line 31
   at CompanyName.MyMeetings.Modules.Administration.Infrastructure.Configuration.Processing.LoggingCommandHandlerWithResultDecorator`2.Handle(T command, CancellationToken cancellationToken) in C:\Projects\dev\dotnet\tests\modular-monolith-with-ddd\src\Modules\Administration\Infrastructure\Configuration\Processing\LoggingCommandHandlerWithResultDecorator.cs:line 35
   at MediatR.Pipeline.RequestPreProcessorBehavior`2.Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate`1 next)
   at MediatR.Pipeline.RequestPostProcessorBehavior`2.Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate`1 next)
   at CompanyName.MyMeetings.Modules.Administration.Infrastructure.Configuration.Processing.CommandsExecutor.Execute[TResult](ICommand`1 command) in C:\Projects\dev\dotnet\tests\modular-monolith-with-ddd\src\Modules\Administration\Infrastructure\Configuration\Processing\CommandsExecutor.cs:line 24
   at CompanyName.MyMeetings.Modules.Administration.Infrastructure.Configuration.Processing.Inbox.ProcessInboxJob.Execute(IJobExecutionContext context) in C:\Projects\dev\dotnet\tests\modular-monolith-with-ddd\src\Modules\Administration\Infrastructure\Configuration\Processing\Inbox\ProcessInboxJob.cs:line 11
   at Quartz.Core.JobRunShell.Run(CancellationToken cancellationToken)

When adding MultipleActiveResultSets=True to the db connection string, the issue obviously disappears. I would avoid using MARS (MultipleActiveResultSets=true) if possible.

Environment : running on Windows, with a localhost SQL Server Let me know if additional details are needed.

Thanks.

[kgrzybek]

I resolved this issue myself. The reason was missing await before command scheduling action:

_commandsScheduler.EnqueueAsync(...

I changed to

await _commandsScheduler.EnqueueAsync(...

and it works.

I don’t know why this bug didn’t occur on the local MS SQL Server on Windows OS. On Docker I had the issue.

Additionally, I changed InMemoryEventsBus to await/async

[kgrzybek]

I didn’t have time to check this issue. Maybe in the meantime, someone has resolved it?