Persistent Work Queue in C#
Imagine I want to have a small network of worker drones possibly on separate threads and possibly on separate processes or even on different PCs. The work items are created by a central program.
I'm looking for an existing product or service that will do this all for me. I know that there is MSMQ and also MQSeries. MQSeries is too expensive. MSMQ is notoriously unreliable. A database backed system would be fine, but I don't want to own/manage/write it. I want to use someone else's work queue system.
Related Articles:
- Here is a similar question, but it's advocating building a custom queue mechanism.
- The queue that I like a lot is this one from Google App Engine.
- http://www.codeproject.com/KB/library/DotNetMQ.aspx
Answer
If you follow some guidelines you can use a database as a queue store with good success, see Using tables as Queues.
SQL Server comes with its own built-in message queuing, namely Service Broker. It allows you to avoid many of the MSMQ pitfalls when it comes to scalability, reliability and high availability and disaster recovery scenarios.
Servcie Broker is fully integrated in the database (no external store, one consistent backup/restore, one unit of failover, no need for expensive two-phase-commit DTC between message store and database, one single T-SQL API to access and program both the messages and your data) and also has some nice unique features such as transactional messaging with guaranteed Exactly-Once-In-Order delivery, correlated message locking, internal activation etc.