RabbitMQ prefetchCount and txSize in spring-rabbit

 Due to following implementation in SimpleMessageListenerContainer of spring-rabbit(1.1.2-RELEASE at this point) library, you should always change txSize as well if you want to decrease prefetchCount for some reason, otherwise txSize will override prefetchCount value.

    protected BlockingQueueConsumer createBlockingQueueConsumer() {
        BlockingQueueConsumer consumer;
        String[] queues = getRequiredQueueNames();
        // There's no point prefetching less than the tx size, otherwise the consumer will stall because the broker
        // didn't get an ack for delivered messages
        int actualPrefetchCount = prefetchCount > txSize ? prefetchCount : txSize;
        consumer = new BlockingQueueConsumer(getConnectionFactory(), this.messagePropertiesConverter, cancellationLock,
                getAcknowledgeMode(), isChannelTransacted(), actualPrefetchCount, this.defaultRequeueRejected, queues);
        return consumer;
    }

Weird RabbitMQ admin webpage behavior with ReferenceError: queue_length is not defined messages.

When you upgrade your RabbitMQ from 3.0.x to 3.1.5 or something, you might see following error on RabbitMQ admin webpage, and admin function doesn't work properly.

ReferenceError: queue_length is not defined

 One and only thing you just need to do in this case is, "Clean your web browser cache", especially cookie.
Once you remove those and reload page, RabbitMQ will require admin/password again. Do log in, you'll see problem has solved.