CODEWITHSUNDEEP
rabbitmq
DeepNightTwo
DeepNightTwo

Reputation: 4961

Does rabbitmq support to push the same data to multi consumers?

I have a rabbitmq cluster used as a working queue. There are 5 kinds of consumers who want to consume exactly the same data.

What I know for now is using fanout exchange to "copy" the data to 5 DIFFERENT queues. And the 5 consumers can consume different queue. This is kind of wasting resources because the data is the same in file queues.

My question is, does rabbitmq support to push the same data to multi consumers? Just like a message need to be acked for a specified times to be deleted.

I got the following answer from rabbitmq email group. In short, the answer is no... and what I did above is the correct way.

http://rabbitmq.1065348.n5.nabble.com/Does-rabbitmq-support-to-push-the-same-data-to-multi-consumers-td36169.html#a36170

Upvotes: 0

Views: 1097

Answers (1)

pinepain
pinepain

Reputation: 12879

... fanout exchange to "copy" the data to 5 DIFFERENT queues. And the 5 consumers can consume different queue. This is kind of wasting resources because the data is the same in file queues.

You can consume with 5 consumers from one queue if you do not want to duplicate messages.

does rabbitmq support to push the same data to multiple consumers

In AMQP protocol terms you publish message to exchange and then broker (RabbitMQ) decide what to do with messages - assume it figured out the queue message intended for (one or more) and then put that message on top of that queue (queues in RabbitMQ are classic FIFO queues which is somehow break AMQP implementation in RabbitMQ). Only after that message may be delivered to consumer (or die due to queue length limit or per-queue or per-message ttl, if any).

message need to be acked for a specified times to be deleted

There are no way to change message body or attributes after message being published (actually, Dead Letter Exchanges extension and some other may change routing key, for example and add,remove and change some headers, but this is very specific case). So if you want to track ack's number you have to re-publish consumed message with changed body or header (depends on where do you plan to store ack's counter, but headers fits pretty nice for this.

Also note, that there are redeliverd message attribute which denotes whether message was already was consumed, but then redelivered. This flag doesn't count redelivers number so it usage is quite limited.

Upvotes: 1

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