MySQL Bugs: #83764: System.NullReferenceException: Object reference not set to an instance of an obj

Bug #83764	System.NullReferenceException: Object reference not set to an instance of an obj
Submitted:	10 Nov 2016 2:46	Modified:	11 May 2017 12:00
Reporter:	nan su	Email Updates:
Status:	Can't repeat	Impact on me:	None
Category:	MySQL Server	Severity:	S3 (Non-critical)
Version:	5.6.23-log - MySQL Community Server	OS:	Windows (WinServer2012R2 Standard)
Assigned to:		CPU Architecture:	Any
Tags:	System.NullReferenceException

Description:
I'am using TransactionScope to do insert/update SQLcmd. throw errors below:

System.NullReferenceException: Object reference not set to an instance of an object.
   at MySql.Data.MySqlClient.NativeDriver.ExecutePacket(MySqlPacket packetToExecute)
   at MySql.Data.MySqlClient.NativeDriver.SendQuery(MySqlPacket queryPacket)
   at MySql.Data.MySqlClient.Driver.SendQuery(MySqlPacket p)
   at MySql.Data.MySqlClient.Statement.ExecuteNext()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
   at MySql.Data.MySqlClient.MySqlTransaction.Rollback()
   at MySql.Data.MySqlClient.MySqlTransactionScope.Rollback(SinglePhaseEnlistment singlePhaseEnlistment)
   at MySql.Data.MySqlClient.MySqlPromotableTransaction.System.Transactions.IPromotableSinglePhaseNotification.Rollback(SinglePhaseEnlistment singlePhaseEnlistment)
   at System.Transactions.DurableEnlistmentAborting.EnterState(InternalEnlistment enlistment)
   at System.Transactions.TransactionStateAborted.EnterState(InternalTransaction tx)
   at System.Transactions.Transaction.Rollback()
   at System.Transactions.TransactionScope.InternalDispose()
   at System.Transactions.TransactionScope.Dispose()

How to repeat:
         using (var t = new TransactionScope(TransactionScopeAsyncFlowOption.Enabled))
            {
             
                this.db.MarketOrders.Add(order);
                await db.SaveChangesAsync();
                try
                {
                    if (ask)
                    {
                        await cas.LockFundsAsync 
                    }
                    else
                    {
                        await cas.LockFundsAsync 
                    }
                }
                catch (Exception ex)
                {
                    throw new Accounting.CapitalAccountNoBalanceOpException(JsonConvert.SerializeObject(order), ex);
                }
                t.Complete();
            }

        }

Hello nan,

Thank you for the bug report.
Could you please provide repeatable test case (exact steps/sample project, sample connection details etc. - please make it as private if you prefer) to confirm this issue at our end?

Thanks,
Chiranjeevi.

I'm experiencing this problem as well and so i have spent some time examining.

Doing the Rollback, the stream in NativeDriver is null when calling ExecutePacket(MySqlPacket). Unfortunately I cannot provide a simple sample project that reproduces the problem in detail. 

But I can provide the specific error message (at the end) and a corresponding test project (MySqlTestProject.rar, MySqlTestDb.rar) where I get the resulting UnhandledException :-(

Please try to deal with it contemporary. It actually affects our customers. Thank you.

*AppDomain::UnhandledException(): IsTerminating: True, Exception: System.NullReferenceException: Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt.
   bei MySql.Data.MySqlClient.NativeDriver.ExecutePacket(MySqlPacket packetToExecute)
   bei MySql.Data.MySqlClient.NativeDriver.SendQuery(MySqlPacket queryPacket)
   bei MySql.Data.MySqlClient.Driver.SendQuery(MySqlPacket p)
   bei MySql.Data.MySqlClient.Statement.ExecuteNext()
   bei MySql.Data.MySqlClient.PreparableStatement.ExecuteNext()
   bei MySql.Data.MySqlClient.PreparableStatement.Execute()
   bei MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   bei MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
   bei MySql.Data.MySqlClient.MySqlTransaction.Rollback()
   bei MySql.Data.MySqlClient.MySqlTransactionScope.Rollback(SinglePhaseEnlistment singlePhaseEnlistment)
   bei MySql.Data.MySqlClient.MySqlPromotableTransaction.System.Transactions.IPromotableSinglePhaseNotification.Rollback(SinglePhaseEnlistment singlePhaseEnlistment)
   bei System.Transactions.DurableEnlistmentAborting.EnterState(InternalEnlistment enlistment)
   bei System.Transactions.DurableEnlistmentActive.InternalAborted(InternalEnlistment enlistment)
   bei System.Transactions.TransactionStateAborted.EnterState(InternalTransaction tx)
   bei System.Transactions.TransactionStateActive.Rollback(InternalTransaction tx, Exception e)
   bei System.Transactions.EnlistableStates.Timeout(InternalTransaction tx)
   bei System.Transactions.Bucket.TimeoutTransactions()
   bei System.Transactions.BucketSet.TimeoutTransactions()
   bei System.Transactions.TransactionTable.ThreadTimer(Object state)
   bei System.Threading.TimerQueueTimer.CallCallbackInContext(Object state)
   bei System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   bei System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   bei System.Threading.TimerQueueTimer.CallCallback()
   bei System.Threading.TimerQueueTimer.Fire()
   bei System.Threading.TimerQueue.FireNextTimers()
   bei System.Threading.TimerQueue.AppDomainTimerCallback()*

Database for MySqlTestProject.rar

Attachment: MySqlTestDb.rar (application/octet-stream, text), 1.05 KiB.

Raising an UnhandledException

Attachment: MySqlTestProject.rar (application/octet-stream, text), 462.09 KiB.

I'm sure MySql.Data.dll make this error. When Sqlcommand timeout,this Exception occurs.
Upgrade this  MySql.Data.dll can fix this problem.

@nan su su 
What's the version number of (your) MySQL.Data.dll?

@Jörg Lippold

U can try this:
https://www.nuget.org/packages/MySql.Data/7.0.6-IR31

Hello nan,

Thank you for the bug feedback and testcast.
I could not repeat the issue at our end using with Visual Studio 2017, Connector/NET 6.9.9 and 7.0.6 IR3 version.

Thanks,
Chiranjeevi.

Screenshot

Attachment: 83764.JPG (image/jpeg, text), 205.02 KiB.

Hi,Chiranjeevi

I mean  7.0.6 IR3 can FIX this error.

MySql.data(version 6.9.9.0) raise TIMEOUT Exception for sure.

Hello nan,

Thank you for the feedback.
I could not repeat the issue at our end using with Visual Studio 2017, Connector/NET 6.9.9 and 7.0.6 IR3 version.
If you can provide more information, feel free to add it to this bug and change the status back to 'Open'.

Thank you for your interest in MySQL.

Thanks,
Chiranjeevi.