我已经同时启动了生产者和消费者。6小时后，生产者生产了大约6亿条消息进入队列，6小时后停止生产者，但消费者继续运行，即使运行18小时后，队列中仍有4亿条消息。有人能告诉我为什么消费者性能非常慢吗？
提前感谢！

@Bean
    public SimpleMessageListenerContainer listenerContainer() {
        SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
        container.setConnectionFactory(connectionFactory());
        container.setQueueNames(this.queueName);
        container.setMessageListener(new MessageListenerAdapter(new TestMessageHandler(), new JsonMessageConverter()));
        return container;
    }
@Bean
    public ConnectionFactory connectionFactory() {
        CachingConnectionFactory connectionFactory = new CachingConnectionFactory(
                "localhost");
        connectionFactory.setUsername("guest");
        connectionFactory.setPassword("guest");
        return connectionFactory;
    }

    @Bean
    public RabbitTemplate rabbitTemplate() {
        RabbitTemplate template = new RabbitTemplate(connectionFactory());
        template.setMessageConverter(new JsonMessageConverter());
        template.setRoutingKey(this.queueName);
        template.setQueue(this.queueName);
        return template;
    }

    public class TestMessageHandler  {
           // receive messages
        public void handleMessage(MessageBeanTest msgBean) {
                   //  Storing bean data into CSV file
             }
    }