[rabbitmq-discuss] Drawbacks and advantages of "autoack" mode?

Thu Apr 14 10:57:10 BST 2011

On 14/04/11 10:49, Simon MacMullen wrote:
> On 14/04/11 10:45, Alfonso Pantoja wrote:
>> specially in critical systems where losing a message is not
>> an option.
>
> In this case, use explicit acks. No excuses :)

Actually, this could have been clearer, since it's often misunderstood.

The point of explicit ack-ing is not to prove that the message traversed 
the network successfully. TCP does that for us. It's to prove that the 
consuming application has taken responsibility for the message without 
crashing - that it's made it into a database or a file, decided it can 
safely ignore it, forwarded it to another system, whatever.

That's why it has to be an explicit step - only the consuming 
application actually knows what constitutes accepting the message.

Cheers, Simon

-- 
Simon MacMullen
Staff Engineer, RabbitMQ
SpringSource, a division of VMware