Randomly getting "The underlying provider failed on Open"

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  I don't know if this is the best category for this.

  My MVC 5 website has been throwing this exception, randomly, for the last month.

  Randomly means it can happen once 2-3 days in a row, or not happen for also 10 days in a row.

  Restarting the app pool does not fix it, all i can do is reboot the server (Windows 2016 server).

  The application(s) connecting to this database are unable to read/write all at once, and any attempt from the code throws this:

  EXCEPTION TYPE: System.Data.Entity.Core.EntityException

  EXCEPTION MESSAGE: The underlying provider failed on Open.

  STACK TRACE: at System.Data.Entity.Core.EntityClient.EntityConnection.<OpenAsync>d__8.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at System.Data.Entity.Core.Objects.ObjectContext.<EnsureConnectionAsync>d__9.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at System.Data.Entity.Core.Objects.ObjectContext.<ExecuteInTransactionAsync>d__3d`1.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<ExecuteAsyncImplementation>d__9`1.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter`1.GetResult()

  at System.Data.Entity.Core.Objects.ObjectQuery`1.<GetResultsAsync>d__e.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter`1.GetResult()

  at System.Data.Entity.Internal.LazyAsyncEnumerator`1.<FirstMoveNextAsync>d__0.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at System.Data.Entity.Infrastructure.IDbAsyncEnumerableExtensions.<SingleOrDefaultAsync>d__38`1.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter`1.GetResult()

  at System.Data.Entity.Internal.Linq.InternalSet`1.<FindInStoreAsync>d__6.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at System.Data.Entity.Internal.Linq.InternalSet`1.<FindInternalAsync>d__0.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at Microsoft.AspNet.Identity.TaskExtensions.CultureAwaiter`1.GetResult()

  at Microsoft.AspNet.Identity.EntityFramework.UserStore`6.<GetUserAggregateAsync>d__67.MoveNext()

  --- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

  at Microsoft.AspNet.Identity.AsyncHelper.RunSync[TResult](Func`1 func)

  at LiveDispatch.Web.Services.AppService.UserCanAccessClient(String userId, Int32 clientId) in R:\Levitica\LiveDispatch\LiveDispatch.Web\Services\AppService.cs:line 621

  at LiveDispatch.Web.API.Controllers.UsersController.GetUsersByRole(Int32 clientId, String role) in R:\Levitica\LiveDispatch\LiveDispatch.Web\API\Controllers\UsersController.cs:line 148

  INNER EXCEPTION: System.Data.Entity.Core.EntityException The underlying provider failed on Open. Void MoveNext()

  InvalidOperationException Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached. System.Exception ExceptionWithStackTrace(System.Exception)

  Now, I use Entity Framework with unit of work and repositories. Every usage of the DbContext is inside a using() block.

  I don't know if this exception is due to a connection leak or a deadlock, but i don't know how to trace them.

  What are all the possible causes for this exception? It's not a connection string configuration or anything that coud fix it right away, because as i said it works well most of the time, till it doesn't suddenly.

  There are at the moment maybe like 50 users using it, most of them thru APIs from a mobile device.

  The database is SQL Server Express. My connection string is as such:

  connectionString="Data Source=localhost;Initial Catalog=my_db_name;Persist Security Info=False;User ID=my_username;Password=my_password;MultipleActiveResultSets=True;"

  Any idea?

  Thanks!

  • Moved by Wendy ZangMicrosoft contingent staff Monday, February 4, 2019 3:20 AM

  Saturday, February 2, 2019 9:51 PM