RabbitMQ The channelMax limit is reached. Try later. [How to Solve]

Anomaly interpretation

In a high concurrency scenario, the number of channels reaches the limit, so they cannot continue to be created

Self-built rabbitmq solution

1. Custom configuration

@Configuration
@Slf4j
public class RabbitMQConfig {


    @Bean
    public RabbitTemplate rabbitTemplate(final ConnectionFactory connectionFactory) {
        CachingConnectionFactory cachingConnectionFactory = (CachingConnectionFactory) connectionFactory;
        // set ChannelMax as 4095
        cachingConnectionFactory.getRabbitConnectionFactory().setRequestedChannelMax(4095);
        final RabbitTemplate rabbitTemplate = new RabbitTemplate(cachingConnectionFactory);
        rabbitTemplate.setMessageConverter(jackson2MessageConverter());
        rabbitTemplate.setMandatory(true);
        rabbitTemplate.setConfirmCallback((correlationData, b, s) -> {
            if(!b){
                log.error("confirmCallBack Sending failed data: {}",correlationData);
                log.error("confirmCallBack Confirmation status: {}",b);
                log.error("ConfirmCallBack Reason for sending failure: {}",s);
            }
        });
        rabbitTemplate.setReturnCallback((message, i, s, s1, s2) -> {
            log.error("returnCallBack message: {}",message);
            log.error("returnCallBack response code: {}",i);
            log.error("returnCallBack response message: {}",s);
            log.error("returnCallBack Switch: {}",s1);
            log.error("returnCallBack Routing Key.{}",s2);
        });
        return rabbitTemplate;
    }

    @Bean
    public Jackson2JsonMessageConverter jackson2MessageConverter() {
        return new Jackson2JsonMessageConverter();
    }
}

2. Modify the configuration of MQ server synchronously
rabbitmq.conf

## Set the max permissible number of channels per connection.
## 0 means "no limit".
##In the configuration file, just enter the following parameters and the value you want to set, if you don't use 2047, then you don't need to configure
# channel_max = 128

Rabbitmq solution for cloud services

For paid versions of MQ cloud services, you can try the following to configure rabbitMq connection caching

springBoot 2.3+

  rabbitmq:
    cache:
      connection:
        size: 1000
      channel:
        size: 64


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