[GitHub] [rocketmq] Pirate-Captain edited a comment on issue #3179: autoCreateTopicEnable set false, No topic route info in name server for the topic: TBW102

[GitBox <gi...@apache.org>]

Pirate-Captain edited a comment on issue #3179:
URL: https://github.com/apache/rocketmq/issues/3179#issuecomment-887164930


   The version is 4.9.0.
   First of all, If set the autoCreateTopicEnable = false，when start the broker, the broker won't register the topic "TBW102" to the nameserver（See the constructor of TopicConfigManager, the line 70）
   ```
   if (this.brokerController.getBrokerConfig().isAutoCreateTopicEnable()) {
                   String topic = TopicValidator.AUTO_CREATE_TOPIC_KEY_TOPIC;
                   TopicConfig topicConfig = new TopicConfig(topic);
                   TopicValidator.addSystemTopic(topic);
                   topicConfig.setReadQueueNums(this.brokerController.getBrokerConfig()
                       .getDefaultTopicQueueNums());
                   topicConfig.setWriteQueueNums(this.brokerController.getBrokerConfig()
                       .getDefaultTopicQueueNums());
                   int perm = PermName.PERM_INHERIT | PermName.PERM_READ | PermName.PERM_WRITE;
                   topicConfig.setPerm(perm);
                   this.topicConfigTable.put(topicConfig.getTopicName(), topicConfig);
               }
   ```
   Second, when start a consumer, it will create a DefaultMQProducer in the MQClintInstance, and will register the producer into the producerTable(MQClientInstance.start line 244), and register the TBW102 to the DefaultMQProducerImpl's topicPublishInfoTable（DefaultMQProducerImpl line 207）
   the entry code is:
   ```
   this.defaultMQProducer.getDefaultMQProducerImpl().start(false);
   ```
   and the register code is (DefaultMQProducerImpl.start() line 199  line 207):
   ```
    boolean registerOK = mQClientFactory.registerProducer(this.defaultMQProducer.getProducerGroup(), this);
                   if (!registerOK) {
                       this.serviceState = ServiceState.CREATE_JUST;
                       throw new MQClientException("The producer group[" + this.defaultMQProducer.getProducerGroup()
                           + "] has been created before, specify another name please." + FAQUrl.suggestTodo(FAQUrl.GROUP_NAME_DUPLICATE_URL),
                           null);
                   }
   
                   this.topicPublishInfoTable.put(this.defaultMQProducer.getCreateTopicKey(), new TopicPublishInfo());
   ```
   
   So, when the MQClientInstance scheduled executes the method updateTopicRouteInfoFromNameServer, it will put the 'TBW102' topic to the topicList, see MQClientInstance.updateTopicRouteInfoFromNameServer line 347
   ```
   // Producer
           {
               Iterator<Entry<String, MQProducerInner>> it = this.producerTable.entrySet().iterator();
               while (it.hasNext()) {
                   Entry<String, MQProducerInner> entry = it.next();
                   MQProducerInner impl = entry.getValue();
                   if (impl != null) {
                       Set<String> lst = impl.getPublishTopicList();
                       topicList.addAll(lst);
                   }
               }
           }
   ```
   the code above will put the topic of  TBW102  to the topicList, the next code update every topic in the topic list.
   
   I don't know whether do i describe clearly.


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