[rabbitmq-discuss] Acks versus Publisher confirms

Tue May 10 10:42:52 BST 2011

Simone,

Please can you, and anyone else, stop posting directly to
rabbitmq-discuss at googlegroups.com ? If you do so then there seem to be
some cases in which replies only make it to google and do not make it
back to the RabbitMQ-discuss mailing list proper.

Please always just post to rabbitmq-discuss at lists.rabbitmq.com.

On Tue, May 10, 2011 at 02:31:31AM -0700, Simone wrote:
> Hello, I read about publisher
> confirms<http://www.rabbitmq.com/blog/2011/02/10/introducing-publisher-confirms/>to
> achieve guaranteed delivery but it's not clear to me how it relates to
> acks on the consumer side in a pub-sub scenario.

It does not really relate client side acks.

Publisher confirms, as I've written before, are about the broker (or
something else further downstream) confirming that they've taken
responsibility for the further delivery of the msg, from the publisher.

Once the broker has received the msg, it will confirm it if when it is
able to.

In the case of transient msgs, this is done as soon as the msg reaches a
queue.

In the case of persistent msgs, this is done once the msg has been
written to disk _and_ fsync'd, _or_ consumed-and-acknowledged by a
consumer, whichever happens sooner.

> Specifically, if I need to achieve the strongest delivery warranty what 
> should I use?

Define "strongest delivery warranty".

Matthew