ApsaraMQ for Kafka:View consumer status

Notes

• A consumer group should subscribe to no more than three topics to prevent message accumulation.

• When you use the assign consumption mode, commit consumer offsets promptly. This prevents consumed messages from being reported as accumulated due to uncommitted offsets.

• If a large number of messages accumulate, compare the message consumption and production rates. If the consumption rate is lower than the production rate, increase the consumption capacity.

View groups that subscribe to a topic

1. Log on to the ApsaraMQ for Kafka console. In the Resource Distribution section of the Overview page, select the region where the ApsaraMQ for Kafka instance that you want to manage resides.

2. On the Instances page, click the name of the instance that you want to manage.

3. In the left-side navigation pane, click Topics.

4. On the Topics page, click the Name of the target topic.

5. On the Topic Details page, click the Subscriptions tab.

   The Online groups that subscribe to the topic list shows all online groups that subscribe to this topic.

6. In the Online groups that subscribe to the topic list, find the target group and click Consumer Details in the Actions column.

   The list shows consumption details for each topic partition.

   Parameter	Description
   Partition ID	The topic partition ID.
   Client	The online consumer currently subscribed to the topic. Note The value is in the <Client ID>_/<IP> format. Client information for offline consumers is not available.
   Maximum Offset	The maximum consumer offset of the partition.
   Consumer Offset	The current consumer offset of the partition.
   Messages Accumulated	The number of accumulated messages in the partition, calculated as Maximum Offset - Consumer Offset. Important Accumulated message count is a key metric. A large value may indicate that consumers are blocked or that consumption is slower than production. Analyze consumer status and increase consumption capacity as needed. For more information, see Reset consumer offsets.

View topics subscribed to by a group

1. On the Instances page, click the name of the instance that you want to manage.

2. In the left-side navigation pane, click Groups.

3. On the Groups page, click the target Group ID.

4. On the Group Details page, click the Consumer Status tab.

   The list displays all topics that the group subscribes to and the Messages Accumulated for each topic.

5. In the Topic list, find the target topic and click Consumer Details in the Actions column.

   The Consumer Details list displays the consumption details of the group for each partition of the topic.

   For parameter descriptions, see the table above.

FAQ

Message accumulation with a working consumer

The consumer may be using the assign consumption mode, which requires manual offset management. Messages may appear accumulated if the consumer offset has not been committed, even after the messages are consumed. To resolve this, commit the consumer offset promptly.

How to increase consumption capacity

You can increase consumption capacity in the following ways:

• Increase the number of consumer instances. You can add instances within a process, each with its own thread, or deploy multiple consumer processes. If the number of consumer instances exceeds the number of partitions, consumption speed does not increase and some instances become idle.

• Increase the number of consumption threads. For more information, see Increase consumption speed.

Does message accumulation always indicate a problem?

Not necessarily. Consider the following scenarios:

• The last consumption time is recent, and accumulated messages fluctuate within a stable range without continuous growth. This is normal and indicates that the client is actively pulling the latest messages.

• Accumulated messages grow steadily while the consumer offset remains unchanged. This indicates that the consumer thread is blocked, has stopped processing messages, and is no longer committing offsets. This is abnormal and means messages have genuinely accumulated.

• Accumulated messages grow while the consumer offset is also advancing. This indicates that the client is still consuming messages, but consumption is slower than production. Increase consumption capacity.

For more information, see Troubleshoot message accumulation in ApsaraMQ for Kafka.

Related documents

• To query consumer status by using an API, see GetConsumerProgress.

• To skip accumulated messages instead of processing them, reset consumer offsets. For more information, see Reset consumer offsets.