NServicebus - One endpoint multiple handlers threading

Question

I have two endpoints.

Endpoint 1:

HandlerForMessage X
HandlerForMessage Y
HandlerForMessage Z

Web endpoint: - No handlers at this time, just sends commands to the bus.

The following happens:

Web -> Send< MessageX >(..);
Endpoint 1: Receive MessageX
Endpoint 1: Handle MessageX and in Handler Bus.Send< MessageY >() and Bus.Send< MessageZ >()
Endpoint 1: Receive MessageY, handle it (this takes 20 seconds)
Endpoint 1: 20 seconds later, after handling MessageY, receive MessageZ and handle it.

Since MessageY, MessageZ have different Handlers can't this be done simultaniously?

Creating another endpoint or moving it to an other endpoint is not an option. I just want it to be multithreaded when it comes to different types of messages (and handlers). I don't see why this is not the default behavior.

How do I configure nservicebus to handle multiple messages at the same time from a different type (with different handler)?

NServiceBus 4.6.5 (or if I need to upgrade to 5, fine I don't mind. Just want to have it multithreaded). Transport: SqlServer and for another project Windows Azure Service Bus

Trevor Pilley Trevor Pilley · Accepted Answer · 2014-12-24T08:28:46

Unless it has changed since I started using NServiceBus, the "unlicenced" version only runs 1 worker thread so it only processes 1 message at a time.

You can alter this in the config by altering the NumberOfWorkerThreads value on the transport, however you need a valid licence in order to increase the number above 1.

<MsmqTransportConfig MaxRetries="0" NumberOfWorkerThreads="1" />

In NServiceBus v4, you need to configure the MaximumConcurrencyLevel value on the TransportConfig:

<TransportConfig MaximumConcurrencyLevel="5" 
                 MaxRetries="2" 
                 MaximumMessageThroughputPerSecond="0"/>

see Failure handling & throttling

NServicebus - One endpoint multiple handlers threading

2 Answers