On 06/28/2011 02:34 PM, Ken Giusti wrote:
This is great feedback - thanks to all.
I think the term "Message Groups" may not be the best term to use as
the name for this feature, as proposed in the qip. I agree that the
term "Message Group" has historically implied a sticky consumer - at
least that's what Google leads me to believe.
The qip wasn't clear regarding the priority of "sticky consumer"
support - as Gordon correctly points out, this qip should lay the
foundation for supporting both behaviours, as (I believe) there is
value in both approaches.
So: 1) I'd like to rename the QIP - is there a better term to use for
the "non-sticky" case than "Message Groups"?
I actually quite like 'Message Groups' as a term, I just think there are
different ways of treating a group.
I think that rather than 'sticky' and 'non-sticky' we really just have
two modes of stickiness, i.e. two scopes for the association between
group and consumer.
In the first mode the group is tied to a consumer only while that
consumer has outstanding, unaccepted messages.
This is sufficient to guarantee strict fifo processing in a group.
It also meets Marnie's requirement of having the 'group as a whole'
processed by the client without having to have any explicit end-of-group
signal that the broker needs to recognise. The client implicitly signals
the end-of-group when it acknowledges the messages in the group.
The second mode extends the scope of the association. The group here is
tied to a consumer for the life of that consumer. This meets Rob's
further requirement of allowing any state required and/or built-up
during processing of the group to be contained within the single consumer.
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