Creating a RocketMQ Topic

Prerequisites

A RocketMQ instance has been purchased.

Creating a Topic

1. Log in to the console.
2. Click in the upper left corner to select a region.
   

   Select the region where your RocketMQ instance is located.

3. Click and choose Middleware > Distributed Message Service for RocketMQ to open the console of DMS for RocketMQ.
4. Click a RocketMQ instance to go to the instance details page.
5. In the navigation pane, choose Topics.
6. Click Create Topic.
7. Configure the topic name and other parameters by referring to Table 1 or Table 2.
   Figure 1 Creating a topic (RocketMQ 4.8.0)
   
   Figure 2 Creating a topic (RocketMQ 5.x)
   

   Table 1 Topic parameters (RocketMQ 4.8.0)

   Parameter	Description
   Topic Name	Name of the topic. A topic name must meet the following requirements: Contains 3 to 64 characters. Contains only letters, digits, percent signs (%), vertical bars (|), hyphens (-), and underscores (_). Cannot start with rmq_sys_. Cannot be the same as the following strings: TBW102 SCHEDULE_TOPIC_XXXX BenchmarkTest RMQ_SYS_TRANS_HALF_TOPIC RMQ_SYS_TRACE_TOPIC RMQ_SYS_TRANS_OP_HALF_TOPIC TRANS_CHECK_MAX_TIME_TOPIC SELF_TEST_TOPIC OFFSET_MOVED_EVENT The topic name must be unique. Otherwise, the topic cannot be created. Once the topic is created, you cannot modify its name. NOTE: A percent (%) or vertical bar (|) contained in a topic name will be converted to an underscore (_) by Cloud Eye. For example, if a topic name is test%01, it will be displayed as test_01 on Cloud Eye.
   Permission	Topic permission, which can be publish/subscribe, publish, or subscribe.
   Brokers	Specify the broker to create the topic on, and the number of queues in the topic. If the instance is deployed on multiple brokers, click Add to add more brokers and set the number of queues in the topic. To add associated brokers, increase the broker quantity. For details, see Modifying RocketMQ Specifications. Increasing the broker quantity increases the maximum topics supported. For example, increasing the broker quantity from 1 to 2 increases the maximum topics from 4,000 of one broker to 8,000 of two brokers.

   Table 2 Topic parameters (RocketMQ 5.x)

   Parameter	Description
   Topic Name	Name of the topic. A topic name must meet the following requirements: Contains 3 to 64 characters. Contains only letters, digits, percent signs (%), vertical bars (|), hyphens (-), and underscores (_). Cannot start with rmq_sys_. Cannot be the same as the following strings: TBW102 SCHEDULE_TOPIC_XXXX BenchmarkTest RMQ_SYS_TRANS_HALF_TOPIC RMQ_SYS_TRACE_TOPIC RMQ_SYS_TRANS_OP_HALF_TOPIC TRANS_CHECK_MAX_TIME_TOPIC SELF_TEST_TOPIC OFFSET_MOVED_EVENT The topic name must be unique. Otherwise, the topic cannot be created. Once the topic is created, you cannot modify its name.
   Message Type	Options: Normal, Ordered, Scheduled, and Transactional. Normal messages: Messages that do not have any features of scheduled messages, ordered messages, or transactional messages. Scheduled messages: Messages that are delivered to consumers only after a specific period after being sent from producers to DMS for RocketMQ. Ordered messages: Messages that are consumed in the exact order that they are produced. Transactional messages: Messages that achieve eventual consistency, delivering distributed transaction processing similar to X/Open XA.

8. Click OK.