ActiveMQ -- message retry mechanism

Message retry mechanism

Official website address

1. Under what circumstances will it cause message resending

   • Consumers use transactions And in session Called in rollback
   • Consumers use transactions And calling commit Previously closed or not commit
   • Consumer end in SESSION_ACKNOWLEDGE In the delivery mode of , stay session Called in recover

2. Message retransmission interval and number of retransmissions

   • The time interval ：1
   • Number of retransmissions ：6

3. Toxic news Poison ACK

   A message was redelivedred Exceeds the default maximum number of repetitions ( Default 6 Time ) when , The consumer will give MQ Send a “Posion ACK”, The news is poisonous , notice broker Don't send it again . Now broker I'll put this message in DLQ（ Dead letter queue ）.

Attribute specification

collisionAvoidanceFactor： Set the positive and negative percentage of the conflict prevention range , Only enable useCollisionAvoidance Parameter . That is to add a time fluctuation range to the delay time . The default value is 0.15.

maximumRedeliveries： Maximum number of retransmissions , Throw an exception after reaching the maximum number of retransmissions . by -1 There is no limit to the number of times , by 0 It means no retransmission . The default value is 6.

maximumRedeliveryDealy： Maximum transmission delay , Only in useExponentialBackOff by true Effective when （V5.5）. Suppose the first reconnection interval is 10ms, The multiple is 2, So the second reconnection interval is 20ms, The third time is 40ms, When the reconnection interval is larger than the maximum reconnection interval , After each reconnection interval is the maximum reconnection interval .

initialRedeliveryDelay： Initial retransmission delay time , Default 1000L

redeliveryDelay： Retransmission delay time , When initialRedeliveryDelay=0 Effective when , Default 1000L

useCollissionAvoidance： Enable anti-collision , Default false

useExponentialBackOff： Enable exponential multiple increment to increase delay time , Default false

backOffMultiplier： The reconnection interval increases , Only values greater than 1 And enable useExponentialBackOff Parameter takes effect . Default 5

verification

• Start the transaction on the consumer side

Session session = connection.createSession(true,  Session.AUTO_ACKNOWLEDGE);

# Do not commit transactions 
// session.commit()

• The producer produces a message , Start consumer

  Don't use it on the consumer side MessageListener Monitor the way to test

1. Start consumers for the first time , Will consume normally once 
2. Then start up 6 Secondary consumer , Will consume data （ Default 6 Time ）
3. The first 7 Time , No message consumption 

In the 7 Next time , The message is marked as toxic , Will enter DLQ, Dead letter queue

Related configuration

If you don't want to try again 6 Next time , Then mark the message as toxic , Can be configured as 3 Time ：topicPolicy.setMaximumRedeliveries(3)

For other configurations, please refer to the official website as follows ：

ActiveMQConnection connection ...  // Create a connection

RedeliveryPolicy queuePolicy = new RedeliveryPolicy();
queuePolicy.setInitialRedeliveryDelay(0);
queuePolicy.setRedeliveryDelay(1000);
queuePolicy.setUseExponentialBackOff(false);
queuePolicy.setMaximumRedeliveries(2);

RedeliveryPolicy topicPolicy = new RedeliveryPolicy();
topicPolicy.setInitialRedeliveryDelay(0);
topicPolicy.setRedeliveryDelay(1000);
topicPolicy.setUseExponentialBackOff(false);
topicPolicy.setMaximumRedeliveries(3);

// Receive a message with the JMS API
RedeliveryPolicyMap map = connection.getRedeliveryPolicyMap();
map.put(new ActiveMQTopic(">"), topicPolicy);
map.put(new ActiveMQQueue(">"), queuePolicy);

springboot Configure retry mechanism

@Component
@EnableJms
public class ActivemqConfig {
    
    
    //.....

	@Bean
    public RedeliveryPolicy redeliveryPolicy(){
    
        RedeliveryPolicy  redeliveryPolicy=   new RedeliveryPolicy();
        // Whether after every attempt to resend failed , Increase the waiting time 
        redeliveryPolicy.setUseExponentialBackOff(true);
        // Number of retransmissions , The default is 6 Time   I'm going to set it to 10 Time 
        redeliveryPolicy.setMaximumRedeliveries(10);
        // retransmit interval , The default is 1 second 
        redeliveryPolicy.setInitialRedeliveryDelay(1);
        // Wait after the first failure before resending 500 millisecond , The second failure and wait 500 * 2 millisecond , there 2 Namely value
        redeliveryPolicy.setBackOffMultiplier(2);
        // Whether to avoid message collision 
        redeliveryPolicy.setUseCollisionAvoidance(false);
        // Set the maximum delay time for retransmission -1  There is no delay, only UseExponentialBackOff(true) by true Effective when 
        redeliveryPolicy.setMaximumRedeliveryDelay(-1);
        return redeliveryPolicy;
    }
}