[rabbitmq-discuss] Prioritizing Between Queues

Sun Apr 21 12:39:43 BST 2013

Hi
Two issues, starting with the simple one:

1. If a consumer (sub) declared a queue with topic binding key that has 
wild pattern, like "type_a.*"
    Then a publisher declared a queue that meets this binding key as well 
via routing key "type_a.something".
    Will the broker dynamically 'subscribe' the consumer above to the new 
queue created by the publisher? even though the consumer did not 'declare' 
such queue specifically, during its queue declaration? i.e. will broker 
push messages to that consumer from the new queue dynamically at run time?

2.I have read everything about AMQP in-queue priority feature requirements.
  I have not found if there is a way for RabbitMQ broker to do the 
following however:

  let clients subscribe to several queues, But prioritize which queue they 
take messages from, in a fashion different than the simple round-robin.
  In other words, we wish to have some algo that Broker could decide about *prioritizing 
queues* for consumers, rather than simple round-robin to them.
  Example:
   we have Q1 responsible for messages of task type A. Type A has priority 1
   we have Q2 responsible for messages of task type B. Type B has priority 2
   .... Q3... Type C.. priority 3.
  Now consumer client(s) subscribe to consume messages from all Queues 
(1..3).
  We wish Broker could give different priority for the three queues. It 
would be even more powerful if for example:
  At some point, there are very little # of messages in Q1. However Q3 is 
'full', or to be more sophisticated, the Rate in which tasks in Q3 
  handled is too slow. We wish to Dynamically change priority for the three 
queues in such case (thus dynamic prioritization of queues)

answers for both questions will significantly influence our decisions about 
the product of choice :)

TIA
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