[rabbitmq-discuss] question on message delivery

Wed Sep 29 15:56:19 BST 2010

On Sep 29, 2010, at 9:16 AM, Vlad Alexandru Ionescu wrote:

> 
> Hi Jon,
> 
> 
> Message ordering is _only_ guaranteed if the messages follow the same path:
> 
>  Publisher Channel -> Exchange -> Queue -> Consumer Channel.
> 
> If any of these four is different for any two messages, then the messages may arrive out of order.

Assuming data like this:

KEY1
KEY1
KEY1
KEY2
KEY2
KEY2

...and assuming three consumers, can I rely on data from KEY2 to arrive after any possible data for KEY1 in each consumer? In other words, on my consumers, I will see this:

Consumer 1: KEY1    Consumer 2: KEY1    Consumer 3: KEY1
Consumer 1: KEY2    Consumer 2: KEY2    Consumer 3: KEY2

and NOT:

Consumer 1: KEY1    Consumer 2: KEY2    Consumer 3: KEY2
Consumer 1: KEY2    Consumer 2: KEY1    Consumer 3: KEY1

The only thing that's different here are the consumer channels. Everything else follows the same path.

Thanks for the info! :)

jb