PDC05 - Day 1 SQL Service Broker Musings

Attending the Building Distributed Asynchronous Applications with SQL Service Broker session at PDC05 and thought I'd share these notes ....

• Service Broker is for SQL Server applications
• The queues are actually database objects
• You can write these applications as stored procedures with T-SQL (or .NET). New T-SQL keywords include:
  • transaction
  • receive
  • conversation
  • waitfor(?)
  • queue
  • xml (as part of SQL Server 2005)
• Reliable messaging included for queuing across databases
• Dialogs are for two-way messaging between services
  • Guaranteed delivery, in-order delivery, secure communications
  • Dialogs can be over a long period of time, or short
• A service is a named endpoint that a message can travel to
• Some basic code might start like:
  create queue [Inventory Queue];
  create service [Inventory]
  on queue [Inventory Queue] ([DEFAULT)];
• Begin a dialog transaction "from" a service, "to" a service and pass on a defined transaction
• On target server, you select from the destination queue
• Can debug the T-SQL service from within Visual Studio.NET
• What if you don't want all the logic within stored procs? Answer: External Activation
  • Messages placed in an Event Queue where an external activitor handles the logic
• Visit www.sqlservicebroker.com
• How do you keep this working without deadlocking? Answer: Conversation Group Locking
  • Dialogs are single-threaded
  • Locking of conversations to prevent collisions [note: look at further]
• Announcing ... Indigo (WCF) channel for the Service Broker!
• Using (datbase stored) certificates and public/private keys for Dialog Security between service endpoints
• Summary: Asynchronous DB "Stuff", Reliable Messaging, Reliable SOA