RocketMQ-重试队列

什么场景下使用重试队列

消费端一直不回传消费结果，MQ认为消息没有收到，Consumer下一次拉取，Broker依然会发送该消息，所以，任何异常都要返回ConsumeConcurrentlyStatus.RECONSUME_LATER，这样MQ会将消息放到重试队列；

重试队列名称为：%RETRY%+consumergroup

配置

Broker配置如下：

messageDelayLevel=5s 5s 5s 5s 5s 5s 5s 5s 5s 5s 5s 5s 5s 5s 5s 5s 5s 5s（测试使用）

默认配置为：messageDelayLevel=1s 5s 10s 30s 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 20m 30m 1h 2h

测试

测试Demo

public static void main(String[] args) throws InterruptedException, MQClientException {

		DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("RetryConsumer");
		consumer.setNamesrvAddr(ExampleConstant.NAMESERVER);
		consumer.setMessageModel(org.apache.rocketmq.common.protocol.heartbeat.MessageModel.CLUSTERING);

		consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_LAST_OFFSET);

		consumer.subscribe("TopicTest", "");

		consumer.setMessageListener(new MessageListenerConcurrently() {
			@Override
			public ConsumeConcurrentlyStatus consumeMessage(List msgs,
				ConsumeConcurrentlyContext context) {
				SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
				System.out.printf(df.format(new Date()) + ", %s Receive New Messages: %s %n", Thread.currentThread().getName(), msgs);
				return ConsumeConcurrentlyStatus.RECONSUME_LATER;
			}
		});

		consumer.start();
    }

测试结果

死信队列

消息在重试队列消费16次（默认次数）后，进入死信队列，名为：%DLQ%+consumergroup