MySQL Bugs: #31703: Should Throw NotSupportedException When Enlisting In Distributed Transaction

Bug #31703	Should Throw NotSupportedException When Enlisting In Distributed Transaction
Submitted:	18 Oct 2007 20:13	Modified:	13 Nov 2007 11:34
Reporter:	Dean Ward	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Connector / NET	Severity:	S2 (Serious)
Version:	5.1.3 RC	OS:	Windows (XP SP2)
Assigned to:		CPU Architecture:	Any
Tags:	Promotable Single Phase Enlistment, PSPE, TransactionScope

Description:
In MySqlConnection::EnlistConnection there is the following code:

if (this.driver.CurrentTransaction == null)
{
   MySqlPromotableTransaction promotableSinglePhaseNotification = new MySqlPromotableTransaction(this, transaction);
   transaction.EnlistPromotableSinglePhase(promotableSinglePhaseNotification);
   ...
}

As MySql Connector/Net doesn't support promotable single phase enlistment just yet it should read:

if (this.driver.CurrentTransaction == null)
{
   MySqlPromotableTransaction promotableSinglePhaseNotification = new MySqlPromotableTransaction(this, transaction);
   if (!transaction.EnlistPromotableSinglePhase(promotableSinglePhaseNotification))
      throw new NotSupportedException();
   ...
}

EnlistPromotableSinglePhase will return false if the transaction is already a distributed transaction - in which case the MySql driver will not be able to successfully participate in it.

How to repeat:
using (TransactionScope txScope = new TransactionScope())
{
   using (SqlConnection sqlConnection = new SqlConnection("Database=Test;Server=(local);Integrated Security=SSPI"))
   {
      sqlConnection.Open();
      using (SqlCommand sqlCommand = new SqlCommand("SELECT * FROM TEST", sqlConnection))
      {
         sqlCommand.ExecuteNonQuery();
      }
   }

   // the transaction scope will promote the ambient transaction
   // to a distributed transaction as soon as the second connection
   // is opened. MySql doesn't support distributed (MSDTC) transactions
   // so should throw a NotSupportedException
   using (MySqlConnection mySqlConnection = new MySqlConnection("Database=test;Server=localhost;Uid=test;Password=test"))
   {
      mySqlConnection.Open();
      using (MySqlCommand mySqlCommand = new MySqlCommand("SELECT * FROM TEST", mySqlConnection))
      {
         mySqlCommand.ExecuteNonQuery();
      }
   }

   txScope.Complete();
}

Suggested fix:
See above.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/36202

Fixed in 5.1.4

Hi Dean and thanks for your report. Our c/NET team was faster than me but I hope you don't mind that the problem is solved :-)

Thanks for your interest in MySQL.

A note has been added to the 5.1.4 changelog: 

Connector/NET would incorrectly report success when enlisting in
        a distributed transaction, although distributed transactions are
        not supported.