Newbie Q: consumer group

[samal <sa...@gmail.com>]

I am having hard time understanding this. Any src where it is explained ?

"Each consumer process belongs to a consumer group and each message is
delivered to exactly one process within every consumer group. Hence a
consumer group allows many
processes or machines to logically act as a single consumer. The concept of
consumer group is very powerful
and can be used to support the semantics of either a queue or topic as
found in JMS. To support queue
semantics, we can put all consumers in a single consumer group, in which
case each message will go to a
single consumer. To support topic semantics, each consumer is put in its
own consumer group, and then all
consumers will receive each message. A more common case in our own usage is
that we have multiple logical
consumer groups, each consisting of a cluster of consuming machines that
act as a logical whole. Kafka has
the added benefit in the case of large data that no matter how many
consumers a topic has, a message is
stored only a single time."


/Samal

Re: Newbie Q: consumer group

[Jun Rao <ju...@gmail.com>]

This is described in a bit more detail in a Kafka paper:
https://cwiki.apache.org/confluence/display/KAFKA/Kafka+papers+and+presentations

Feel free to ask again if you still have questions after reading the paper.

Thanks,

Jun

On Sun, Apr 15, 2012 at 9:24 PM, samal <sa...@gmail.com> wrote:

> I am having hard time understanding this. Any src where it is explained ?
>
> "Each consumer process belongs to a consumer group and each message is
> delivered to exactly one process within every consumer group. Hence a
> consumer group allows many
> processes or machines to logically act as a single consumer. The concept of
> consumer group is very powerful
> and can be used to support the semantics of either a queue or topic as
> found in JMS. To support queue
> semantics, we can put all consumers in a single consumer group, in which
> case each message will go to a
> single consumer. To support topic semantics, each consumer is put in its
> own consumer group, and then all
> consumers will receive each message. A more common case in our own usage is
> that we have multiple logical
> consumer groups, each consisting of a cluster of consuming machines that
> act as a logical whole. Kafka has
> the added benefit in the case of large data that no matter how many
> consumers a topic has, a message is
> stored only a single time."
>
>
> /Samal
>