MSMQ one (queue) to many (listeners) scenario
I have this scenario: One client sends a message into a msmq queue instance and there are 3 processes which listen on this queue. I want to be able to let every one of those instances pick a different message and process it.
I know that is a common usage scenario for queues and i already have working code for this using MSMQ, .NET and C#.
However i am wondering if msmq is my best option here - the documentation clearly states that MSMQ is meant for "one to one" communication, meaning that there shouldnt be more than one listener.
That kind of leaves me wondering, is what i am doing the right solution for my use case? Or is it the other way round, do i have to create one queue per listener and distribute the messages in a preceeding part of the workflow?
A link to a working example demonstrating the usage of MSMQ in this type of scenario would be greatly appreciated.
Thanks
Answer
As I understand it you are using multiple listeners to do something like load balancing. This is an absolutely valid scenario and it is often used in clustered environments or in load balancing scenarios where a single listener is not able to consume all incoming messages. Btw. clustered BizTalk consumes MSMQ messages in the same way.
The one-to-one is meant as one message is passed to one listener but it doesn't mean that each queue can have only single listener. If all listeners do the same processing and it doesn't depend which one will pick the message, it is still one-to-one.
It is also possible to use one queue to deliver one message to multiple listeners. This scenario is not recommended with MSMQ even though it is technically possible with triggers.
If your listeners listen only for messages with some special properties, identifying which listener should consume the message (i.e. you search for messages in the queue), you should definitely use three queues instead.