Scenario
In RocketMQ, a subscription group refers to a logical concept used to identify a group of consumers who collectively consume messages on the same topic.
A subscription group allows multiple consumers to consume messages on the same topic simultaneously for load balancing and HA of messages. When a message is sent to a topic in RocketMQ, RocketMQ pushes the message to the consumers in all subscription groups that have subscribed to the topic.
Each subscription group contains one or several consumers, which run in the same application or different applications. Consumers can consume messages in cluster or broadcasting mode.
In the cluster mode, consumers in a subscription group work together in the form of consumer groups, and a message is consumed by only one consumer in the subscription group. RocketMQ distributes messages to different consumers based on their load balancing policies, achieving load balancing and HA of messages.
In broadcasting mode, each consumer in the subscription group consumes messages independently, and each message is consumed once by all consumers in the subscription group. The broadcasting mode applies to scenarios where all consumers need to process the same message.
Subscription groups enable RocketMQ to support scale-out and fault tolerance. You can add consumers or deploy multiple consumer instances to improve consumption and availability.
In RocketMQ, each subscription group must have a unique name to differentiate it from other subscription groups. Each subscription group can subscribe to one or more topics to meet the requirements of different business scenarios.
Lists of Subscription Groups
1. Go to the subscription group management menu to view the subscription group list. If the list is empty, create a subscription group. For details about how to create a subscription group, see Specific Operation Steps.
2. You can query by cluster, broker and subscription group name. Select the query content from the drop-down menu or enter the query information. Click Query to show the required subscription group data.
3. You can view basic subscription group information, including subscription group name, BrokerName, BrokerID, start offset, consumption mechanism, and whether to enable consumption. You can also switch between Enable Consumption and Disable Consumption.
Topic List
Topic List: You can view the list of topics that can be consumed by the subscription group, and the consumption TPS limits.
1. You can enter keywords to search topic data.
2. Select the topic to be consumed and click OK to save it.
3. You can also select Subscribe to All or Cancel Order.
Download
Export the configuration and routing information of the selected subscription group as an excel file.
Note:
If you have selected a subscription group, the system exports the information of the selected subscription group. If you have not selected a subscription group, the system exports all subscription group information under the selected broker of the cluster.