Florin Lazar - Consistency Checkpoint

Intro for Microsoft Azure .Net Service Bus

2009-04-03T02:10:00Z

Clemens Vasters gives a great introduction to Microsoft Azure .Net Service Bus and its 4 feature areas: Naming, Registry, Connectivity, and Eventing. Find it at http://vasters.com/clemensv/PermaLink,guid,92d78bee-2cfd-4a29-95ab-c5abb9b905e7.aspx...(read more)

Atbroker.exe application error - CTRL-ALT-END in a remote session

2008-11-26T01:20:00Z

I use remote desktop daily. The Atbroker.exe application error followed by black screen seemed to be gone for a while. Now it is back. The only solution that I know of and which works most of the times is "CTRL-ALT-END" (the equivalent of “CTRL-ALT-DEL” for remote sessions) followed by ESC. When it doesn’t work, I need to log in with another user and kill the session with the issue or reboot the box – nasty....(read more)

When not to use transactions and where you can't use transactions

2008-05-08T22:21:00Z

Transactions are great when everyone plays in. You group a set of activities together under a transaction and you start executing them. If anything bad happens along the way or something doesn't go as planned, invoke rollback and all is taking care of automatically by the infrastructure: everything is undone and the app returns to the state before the transaction started; recovery and consistency is a piece of cake with nothing to worry about. But... I can't really use transactions for long running...(read more)

MSDTC and COM+ Configuration Tool in Vista

2008-05-07T22:01:00Z

To access the MSDTC and COM+ configuration tool in Windows Vista, also known as Component Services MMC, you have the following options: 1. Run “dcomcnfg” 2. Or run: %SystemRoot%\System32\comexp.msc 3. Or if you prefer, you can add a shortcut to %SystemRoot%\System32\comexp.msc in Control Panel If you have UAC on and you want to do 3, first make a shortcut for %SystemRoot%\System32\comexp.msc on your Desktop and then move it to Control Panel....(read more)

Exception Handling without catch(Exception)

2008-05-07T06:58:00Z

The design guidelines for exception handling are quite clear on avoiding “catch all” and/or avoiding catching exceptions you can’t handle. But there are cases when you really need to know if the try block completed successfully or not, and possibly take some action. One way one could achieve this without breaking the guideline is to set a flag at the end of the try block and then query it inside finally : bool workCompleted = false ; try { DoSomething(); DoSomethingMore(); workCompleted = true ;...(read more)

Working with CMD and Long Path Names

2008-05-06T19:54:00Z

I like using the command prompt for a lot of things and working with long (or very long) path names is something that is common these days. Fortunately, you can customize cmd by using "prompt". Do a “prompt /?” in a command window to see all the options. I like it simple and I use: “PROMPT=$p$_$+$g”. This gives: C:\Windows\System32\Msdtc\Trace > To persist it, set it as an environment variable....(read more)

How to Use System.Data with System.Transactions and Maintain Atomicity and Data Consistency

2008-05-05T10:04:00Z

The Bug I call it a bug. Initially I was persuaded to believe it was a feature; later I was "convinced" that it is now a matter of app compat and it can't be changed anymore. Let’s look at the following code: SqlConnection connection1 = new SqlConnection(connectionString); using(TransactionScope txScope = new TransactionScope()) { connection1.Open(); SqlCommand command1 = new SqlCommand(commandString1, connection1); command1.ExecuteNonQuery(); SqlCommand command2 = new SqlCommand(commandString2,...(read more)

Limitation of TransactionScope (and using)

2008-05-05T08:38:00Z

If you read the documentation for TransactionScope , you will find: "If no exception occurs within the transaction scope […], then the transaction in which the scope participates is allowed to proceed. If an exception does occur within the transaction scope, the transaction in which it participates will be rolled back. " Later the doc says: “When your application completes all work it wants to perform in a transaction, you should call the Complete method only once to inform that transaction manager...(read more)

Avoiding Transaction Promotion with Multiple Connections - Improvements in System.Data and SQL Server 2008

2008-05-02T23:02:00Z

Great news! The new updates added to System.Data and SQL Server 2008 finally allow multiple Open/Close connections to the same SQL Server without promoting the transaction to MSDTC. This was by far the most requested feature for the System.Transactions/System.Data/SQL Server combination. There is no more the need to write workarounds like ConnectionScope to avoid promotions. Now I can write as many Open/Close, Open/Close as I need to, without worrying about promotion: transacted(()=> { using (SqlConnection...(read more)

A Simpler TransactionScope

2008-03-24T19:33:00Z

In .Net 3.5 I can write a transactional code block as follows: transacted(()=> { using (SqlConnection connection = new SqlConnection(connectionString)) { connection.Open(); SqlCommand command1 = new SqlCommand(commandString1, connection); command1.ExecuteNonQuery(); SqlCommand command2 = new SqlCommand(commandString2, connection); command2.ExecuteNonQuery(); } }); No need for using and no need to remember to call Complete at the end of the block. To enable this I need to write just a few lines...(read more)

Flowing or propagating transactions in .Net

2008-02-20T18:36:00Z

System.Transactions transactions are bounded to the appdomain. Which means that if you make in-appdomain calls from inside a TransactionScope, those calls will share the transaction. This also means that if you need to make a call outside the current appdomain, or outside the process, you will need to "flow" the transaction.

To flow a System.Transactions transaction, there are a few options:

a. if you are using serialization

//sender code
using(TransactionScope ts = new TransactionScope())
{
  RemoteCallUsingSerialization(Transaction.Current, other parameter); // this is the call to other appdomain/process
  // notice I added a new parameter of type System.Transactions.Transaction  

  ts.Complete();
}

//destination code
void RemoteCallUsingSerialization(System.Transactions.Transaction tx, other parameter)
{
  using(TransactionScope ts2 = new TransactionsScope(tx))
  {
   // access transactional resourses like a database; this code will execute as part of the same transaction
   ts2.Complete();
  }
}

b. if you are not using serialization

//sender code
using(TransactionScope ts = new TransactionScope())
{  
  RemoteCall(TransactionInterop.GetTransmitterPropagationToken(Transaction.Current), other parameter); // this is the remote call
  // notice I added a new parameter of type byte[]  

  ts.Complete();
}

//destination code
void RemoteCall(byte[] tx, other parameter)
{
  using(TransactionScope ts2 = new TransactionsScope(TransactionInterop.GetTransactionFromTransmitterPropagationToken(tx)))
  {
   // access transactional resourses like a database;
   // this code will execute as part of the same transaction
   ts2.Complete();
  }
}

c. if .Net 3.0 or higher is an option, you can use WCF and its support for transactions using attributes: http://msdn2.microsoft.com/en-us/library/aa347993.aspx

Remark: When the transaction is flown outside the current appdomain, it will get upgraded to a distributed transaction (or MSDTC transaction).

If you are not using .Net, see http://blogs.msdn.com/florinlazar/archive/2004/10/02/236965.aspx for propagating transactions in C++.

TIP is now deprecated

2008-01-23T01:10:00Z

TIP is getting deprecated - see the note at http://msdn2.microsoft.com/en-us/library/ms679484(VS.85).aspx
If the native OleTx protocol used by MSDTC and System.Transactions is not friendly enough for your firewall, you should consider the WS-AtomicTransactions protocol provided through Windows Communication Foundation in .Net Framework 3.0 and higher: http://msdn2.microsoft.com/en-us/library/ms730266.aspx

MSDN Magazine Article on Transactional File System

2007-07-11T18:25:00Z

Jason Olson describes the Transactional NTFS and how you can take advantage of it in your applications: http://msdn.microsoft.com/msdnmag/issues/07/07/NTFS/default.aspx

WCF in Romania

2007-05-03T06:27:00Z

These days I'm in Romania with a tour at 3 universities (in Bucharest, Cluj and Iasi) talking about Windows Communication Foundation, distributed systems and web services. Adi Oltean is also talking about storage technologies in Windows.

So far the seminars were received really well and we made a lot of friends. I'm really pleased to be able to contribute to the adoption of WCF and to demonstrate the amazing value and power of WCF with its productivity, interoperability and extensibility features.

More details at http://reg.studentclub.ro/RegisterForEvent.aspx?idEveniment=55 (in romanian).

I would like to thank Todi Pruteanu for organizing these events.

"Orcas" March 07 CTP: Support for OASIS WS-AT 1.1 and WS-Coord 1.1

2007-03-08T00:58:00Z

In the "Orcas" March 2007 CTP for Visual Studio and .Net, Windows Communication Foundation brings support for OASIS specifications WS-AtomicTransaction 1.1 and WS-Coordination 1.1. WCF will have side-by-side support with the 1.0 versions of these specs.

To use the new version of WS-AT, you can specify the new WS2007HttpBinding, or, if you already use the NetTcpBinding, you can set the TransactionProtocol to WSAtomicTransactions11.