Rabbitmq concurrent consumers in Spring boot

Question

I'm using @RabbitListener annotation and SimpleRabbitListenerContainerFactory bean for parallel execution of rabbitmq messages and setting the min and max concurrent consumers in the following way :

@Bean
public SimpleRabbitListenerContainerFactory rabbitListenerContainerFactory() {
    SimpleRabbitListenerContainerFactory factory = new SimpleRabbitListenerContainerFactory();
    factory.setConnectionFactory(connectionFactory());
    factory.setConcurrentConsumers(MIN_RABBIT_CONCURRENT_CONSUMERS);
    factory.setMaxConcurrentConsumers(MAX_RABBIT_CONCURRENT_CONSUMERS);
    factory.setConsecutiveActiveTrigger(1);
    factory.setAcknowledgeMode(AcknowledgeMode.MANUAL);
    return factory;
}

The min limit is 3 and the max limit is 10. With this configuration, only 3 messages are getting executed parallelly, even though there are 12 messages in the queue.

Please tell me what is wrong with the config?

Solution 1

With the default configuration, a new consumer will be added every 10 seconds if the other consumers are still busy.

The algorithm (and properties to affect it) is described here.

Solution 2

You can create max concurrent consumers using rabbitMQ annotation

@RabbitListener(queues = "your-queue-name", concurrency = "4")
public void customCheck(Object requestObject) {
    // process
}

Comments

[jnodorp]

Documentation moved to docs.spring.io/spring-amqp/reference/#listener-concurrency

[Gary Russell]

Thanks; link fixed.

[Gary Russell]

Don't ask new questions on year-old answers. Yes, it comes standard with Spring AMQP. If you need more information, ask a new question.

[S Khandelwal]

Can concurrency be changed every time this method get called?

[Vinit Jordan]

S Khandelwal it will increase till the concurrent number you have added. It will not consume requests more then given concurrency.