If a message consumption exception occurs, you can check the status of consumers in the Message Queue for Apache RocketMQ console to identify the potential cause. You can view the information of consumer instances in a group identified by a group ID. You can also view the information of each consumer instance in the group.

Scenarios

The information of consumers includes the online or offline state, subscription, consumption transactions per second (TPS), message accumulation, and thread stack information. The information is often used in the following troubleshooting scenarios:

  • Subscription inconsistency
  • Message accumulation
    • Issue: On the Group Details page, the value of the Real-time Accumulated Messages field within a group ID is higher than expected.
    • Solution: For more information about how to handle accumulated messages, see How can I handle accumulated messages?

View the information of a group ID

To view the information of the consumer instances identified by a group ID, perform the following steps:

  1. Log on to the Message Queue for Apache RocketMQconsole.
  2. In the left-side navigation pane, click Instances.
  3. In the top navigation bar, select a region. In this example, select China (Hangzhou).
  4. On the Instances page, find the instance, click More in the Actions column, and then select Groups from the drop-down list.
  5. On the Groups page, find the group ID and click Details in the Actions column.

    The following figure shows a result.

    consumer_states
Table 1. Fields
Field or icon Description
Consumer Status
  • If at least one of the consumer instances within the group ID is online, Online is displayed in this field. At the bottom of the page, the information of the online consumer instances is displayed in the Client Connection Information section.
  • If all consumer instances within the group ID are offline, Offline is displayed in this field. No information is displayed in the Client Connection Information section.
Is Subscription Consistent This field indicates whether the subscription information of all consumer instances within the group ID is consistent. For more information, see Subscription consistency.
Real-time Consumption Speed The total TPS at which messages are received by the consumer instances within the group ID. Unit: messages/s.
Real-time Message Accumulation The total number of messages that are not consumed by the consumer instances within the group ID.
Last Consumed At The time when the consumer instances within the group ID last consumed a message.
Message Delay Time The difference between the production time of the earliest unconsumed message within the group ID and the current time.

View the information of a consumer instance within a group ID

If the group ID is in the Online state, you can view the information of each online consumer instance within the group ID in the Client Connection Information section. The information includes Client ID, Host IP/Public IP, Process ID, and Messages Accumulated.

View more information

If you want to view more information about a consumer instance, click More in the Actions column. The information includes the consumption statistics, consumption retry statistics, and client stack information. The following figure shows an example.

more_detialmore_detialView the alerting information within a group ID

To view the alert monitoring status within a group ID, click the Cloud Monitor tab at the bottom of the page. The following figure shows an example.

cloud_monitiorView the consumption information within a group ID

To view the total message consumption and TPS of a subscribed topic within the group ID, click the Message Consumption Chart tab at the bottom of the page. The following figure shows an example.

message_consumer_table

References

If you have set metrics and received alerts about message accumulation, see What can I do if I receive a message accumulation alert?