There are lot of posts about the messages order (FIFO), in you have a normal situation(one producer one consumer without network problem) you don’t have any problem. But as you can read here
In particular note the "unless the redelivered field is set" condition,
which means any disconnect by consumers can cause messages pending
acknowledgement to be subsequently delivered out of order.
Also, for example if you publish a message and there is some error during the publish you have to re-publish the message in the correct order.
It means that if you need absolutely the messages order you have to implement it, for example marking each packet with a sequential number, and you should also implement confirm publish .
I think, but this is my opinion, that when you use a messages system you shouldn’t worry about the messages order, because it should be your application able to manage the data.
Having said that,if we suppose that the 100 queues have to handle the same messages kind, you could use an ThreadPoolExecutor and shared it from all consumer.
For example:
public class ActualConsumer extends DefaultConsumer {
public ActualConsumer(Channel channel) {
super(channel);
}
@Override
public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body) throws java.io.IOException {
MyMessage message = new MyMessage(body);
mythreadPoolExecutorShared.submit(new MyHandleMessage(message))
}
}
In this way you can balance the messages between the threads.
Also for the threadPool you can use different policies, for example a static allocation with fixed thread number or dynamic thread allocation.
Please read this post about the threadpool resize (Can you dynamically resize a java.util.concurrent.ThreadPoolExecutor while it still has tasks waiting)
You can apply this pattern to all nodes, in this way you can balance the dispatching messages and assign a correct threads number.
I hope it can be useful,I'd like to be more detailed, but your question is a bit generic.
