Strange 'System.InvalidOperationException: Invalid operation. The connection is closed.' exceptions

[schuettecarsten]

Description

Sometimes we get strange System.InvalidOperationException: Invalid operation. The connection is closed. and System.NullReferenceException: Object reference not set to an instance of an object. exceptions. Our code runs as Hangfire jobs. Most time, jobs work fine. But if we run into failure condition, we get the first exception on the first try, the second exception on the retry, then the first exception again on the next try and so on. This did not happened with earlier versions of EntityFramework.Plus libraries. This exception also occurs on the same statement, which is not the first SQL on the job.

The LINQ statement:

	var query = this.Query().Where(x => x.TenantID == tenantID);
	query = query.IncludeOptimized(x => x.GroupMemberships);
	query = query.IncludeOptimized(x => x.GroupMemberships.Select(y => y.User));
	query = query.IncludeOptimized(x => x.AssignedProduct);
	query = query.IncludeOptimized(x => x.AssignedProduct.Product);
	return query;

Exception

System.InvalidOperationException: Invalid operation. The connection is closed.
   at System.Data.SqlClient.SqlDataReader.TryHasMoreResults(Boolean& moreResults)
   at System.Data.SqlClient.SqlDataReader.TryNextResult(Boolean& more)
   at System.Data.SqlClient.SqlDataReader.NextResult()
   at Z.EntityFramework.Plus.QueryFutureBatch.ExecuteQueries()
   at Z.EntityFramework.Plus.QueryFutureEnumerable`1.GetEnumerator()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at Z.EntityFramework.Plus.QueryIncludeOptimizedParentQueryable`1.CreateEnumerable()
   at System.Threading.Tasks.Task`1.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
--- 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 Z.EntityFramework.Plus.LazyAsyncEnumerator`1.<FirstMoveNextAsync>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.Infrastructure.IDbAsyncEnumerableExtensions.<ForEachAsync>d__2`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.NullReferenceException: Object reference not set to an instance of an object.
   at System.Data.SqlClient.SqlDataReader.GetInt64(Int32 i)
   at lambda_method(Closure , Shaper )
   at System.Data.Entity.Core.Common.Internal.Materialization.Shaper.HandleEntityAppendOnly[TEntity](Func`2 constructEntityDelegate, EntityKey entityKey, EntitySet entitySet)
   at lambda_method(Closure , Shaper )
   at System.Data.Entity.Core.Common.Internal.Materialization.Coordinator`1.ReadNextElement(Shaper shaper)
   at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.RowNestedResultEnumerator.MaterializeRow()
   at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.RowNestedResultEnumerator.MoveNext()
   at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.ObjectQueryNestedEnumerator.TryReadToNextElement()
   at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.ObjectQueryNestedEnumerator.ReadElement()
   at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.ObjectQueryNestedEnumerator.MoveNext()
   at Z.EntityFramework.Plus.QueryFutureEnumerable`1.SetResult(IEnumerator`1 enumerator)
   at Z.EntityFramework.Plus.QueryFutureEnumerable`1.SetResult(DbDataReader reader)
   at Z.EntityFramework.Plus.QueryFutureBatch.ExecuteQueries()
   at Z.EntityFramework.Plus.QueryFutureEnumerable`1.GetEnumerator()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at Z.EntityFramework.Plus.QueryIncludeOptimizedParentQueryable`1.CreateEnumerable()
   at System.Threading.Tasks.Task`1.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
--- 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 Z.EntityFramework.Plus.LazyAsyncEnumerator`1.<FirstMoveNextAsync>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.Infrastructure.IDbAsyncEnumerableExtensions.<ForEachAsync>d__2`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 ...

Further technical details

• EF version: 6.2 (.NET)
• EF Plus version: 5.1.8
• Database Provider: Sql-Server (2017)

[JonathanMagnan]

Hello @schuettecarsten ,

This did not happened with earlier versions of EntityFramework.Plus libraries

Can you let us know which version of the library didn't throw the error so we could compare change?

Best Regards,

Jon

---

Performance Libraries context.BulkInsert(list, options => options.BatchSize = 1000); Entity Framework Extensions • Entity Framework Classic • Bulk Operations • Dapper Plus

Runtime Evaluation Eval.Execute("x + y", new {x = 1, y = 2}); // return 3 C# Eval Function • SQL Eval Function

[zabulus]

We also have the same exception in "Z.EntityFramework.Plus.EF6" Version="6.14.2". Will try to update to latest version and see if this will be resolved. If this helps, we experienced multiple timeout exceptions before the InvalidOperationException occurs.

[JonathanMagnan]

Hello @zabulus ,

Let us know when you will have more information.

I don't think this issue is fixed even using the latest version as it might be related to the multiple timeout exception.

Best Regards,

Jon

[JonathanMagnan]

Hello @zabulus,

Since our last conversation, we haven't heard from you.

We will close this issue, if you provide more information we will re-open it.

Don’t hesitate to contact us, we are always here to assist you.

Looking forward to hearing from you,

Jon