doc-exports/docs/dms_rocketmq/umn/hrm-ug-008.html

Creating a RocketMQ Topic

A topic is the basic unit for sending and receiving messages. After creating a RocketMQ instance, you must manually create a topic, and publish and subscribe to messages. A message producer sends messages to this topic. A message consumer consumes messages by subscribing to this topic.

Prerequisite

A RocketMQ instance has been created.

Creating a Topic

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

   DMS instances in different regions cannot communicate with each other over an intranet. Select a nearest location for low latency and fast access.

3. Click and choose Application > Distributed Message Service for RocketMQ to open the DMS for RocketMQ page.
4. Click a RocketMQ instance name to go to the instance overview page.
5. In the navigation pane, choose Instance > Topics.
6. Click Create Topic.
7. Configure the topic name and other parameters by referring toTable 1.
   Figure 1 Creating a topic
   

   Table 1 Topic parameters

   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 (_). 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. 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	Select the message type. Options: Normal: Messages that do not have any features of scheduled messages, ordered messages, or transactional messages. Scheduled: Messages that are delivered to consumers only after a specific period after being sent from producers to DMS for RocketMQ. Ordered: Messages that are consumed in the exact order that they are produced. Transactional: Messages that achieve eventual consistency, delivering distributed transaction processing similar to X/Open XA. Default: Normal
   Description	Topic description. The value contains 0 to 200 characters.

8. Click OK.

Parent topic: Configuring a Topic