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spring-bootrabbitmqspring-rabbit

SimpleMessageListenerContainer subscribing to multiple queues with RetryOperationsInterceptor

I am playing with the SimpleMessageListenerContainer that is subscribed to 3 different queues. The SimpleMessageListenerContainer has been configured with a RetryOperationsInterceptor that has a exponential back off policy.

My SimpleMessageListenerContainer has been configured with :

container.addQueueNames("news.politics","news.science","news.tech");
container.setMaxConcurrentConsumers(10);
container.setAdviceChain(new Advice[]{retryInterceptor});

If a message from one of the 3 queue thats been consumed enters an erroneous state resulting in an exception, the consumer triggers the exponential back of policy as predicted. However, I am noticing that the consumer STOPS doing round robin, to process messages on the other 2 queues. I was thinking since the consumer is set with "MaxConcurrentConsumer" of 10, the consumer will start to spawn consumer threads and round robin the rest of the queues.

  1. Is this the normal behavior of SimpleMessageListenerContainer?
  2. Can this behavior be adjusted?
  3. For my use-case, would it be recommended to have one SimpleMessageListenerContainer per queue to keep them segregated? Perhaps come up with a decorator CompositeSimpleMessageListener container, that has internally a map of SimpleMessageListenerContainers per queue?
Solution

  • The algorithm to increase consumers is limited; if the retry interceptor suspends the consumer thread, it will prevent new consumers from being started.

    Either increase the concurrentConsumers (to at least 3) or switch to the DirectMessageListenerContainer. See choosing a container.