RocketMQ-重試隊列

什麼場景下使用重試隊列

消費端一直不回傳消費結果，MQ認爲消息沒有收到，Consumer下一次拉取，Broker依然會發送該消息，所以，任何異常都要返回ConsumeConcurrentlyStatus.RECONSUME_LATER，這樣MQ會將消息放到重試隊列；

重試隊列名稱爲：%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（測試使用）

默認配置爲：messageDelayLevel=1s 5s 10s 30s 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 20m 30m 1h 2h

測試

測試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<MessageExt> 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();
    }

測試結果

死信隊列

消息在重試隊列消費16次（默認次數）後，進入死信隊列，名爲：%DLQ%+consumergroup