What is a transaction bridge in MSDTC?

Question

When MSDTC starts up, it creates an event log entry that displays all the startup settings. One of them is "Transaction Bridge Installed". I assume this is similar to a JBoss Transaction Bridge. Google has suprisingly few search results, other than JBoss documentation and a few references on pages here and there. Not enough that I really get it.

The only MS documentation I could find is references to them in error messages, like here: http://technet.microsoft.com/en-us/library/cc726307(v=ws.10).aspx

My question is, what are some examples of Transaction Bridges for MS DTC, what do you need them for and is there any documentation on using them? Is there any documentation on creating them?

Answer 1

The transaction brigde is what MS-DTC (Distributed Transaction Coordinator) uses to manage transactions across several systems, is an implementation of the Two Phase Commit. Basically, its used internally by Windows to manage a common transaction across several systems, something like this:

Take a C# application running on IIS.

You enter a TransactionScope, and delete some records from an SQL Server instance. Now (still in the TransactionScope) you connect to Oracle, to insert some rows.

At this point, you have an open transaction in each RDBMS, but both transactions are combined into the Distributed Transaction by DTC.

When you commit your TransactionScope, a commit will be issued to both systems, and only if both systems have to successfully execute the commit for the distributed transaction to finish correctly. On the other hand if you issue a rollback, both systems will roll back their transactions.

The trasaction brigde is what its used to communicate with those other systes that understand the 2PC (Two Phase Commit) Protocol.

Hope this helps.

Answer 2

TransactionBridge Class

This API supports the .NET Framework infrastructure and is not intended to be used directly from your code. An internal class that is used for transactions.

So it is used internally by MSDTC and not intended to be called by you directly, hence there won't be any examples out there.