[rabbitmq-discuss] Vanishing of persistent messages on durable, auto-deleting queue with dead-lettering

Mon Jul 16 11:37:44 BST 2012

First thank you for your answer. I spend some time thinking about actual 
behavior, consequences
of this status quo and also how I can achieve my goal.

2012-07-01 20:23, Matthias Radestock writes:
>
> We deliberately kept the set of operations susceptible to 
> dead-lettering small, to avoid unintended consequences. It is possible 
> that actions like auto-deletion, queue lease expiry, explicit deletion 
> and purging should all trigger the dead-letter mechanism, but I'd like 
> to see compelling use cases first before making such a change. 

I will describe the case I am dealing with:
We send some tasks to rabbit's exchange. To achieve load balancing at 
rpc servers x-consistent-hash
is used. Auto-deleting queues with dead-lettering are fitting there 
perfectly, because when one
of consuments goes down his queue is deleted and then new messages are 
distributed only between
active consumers (due to auto-deleting) and also we can preserve badly 
processed commands
for another try or examination in another queue (due to dead-lettering).

But as consequence of choosing auto-deleting queue also some part of 
messages (which won't be
dead-lettered when queue will be discarded). As there are cases when 
loosing messages is not
an option I think if actual behavior is consistent with spirit of 
dead-lettering's aims (imho to save
undeliverable messages).

I would appreciate if you could submit your view on this case.

Regards,
Ernest