This topic describes the limits on some metrics in Message Queue for Apache RocketMQ. To prevent program exceptions, you must set these metrics to values within these limits when you use Message Queue for Apache RocketMQ.

The following tables describe the limits.

Item Limit Description
Maximum number of Message Queue for Apache RocketMQ instances in a single region
  • Standard Edition: 8
  • Enterprise Platinum Edition: not limited
N/A
Length of a topic name 64 characters A topic name can be up to 64 characters in length. If the topic name is more than 64 characters in length, messages in the topic cannot be subscribed to or published.
Number of groups in a single instance 1,000 A maximum of 1,000 groups can be created in a single instance. We recommend that you reuse or delete groups that you do not need in a timely manner. If you require more than 1,000 groups, submit a ticket.
Message size
  • Normal message or ordered message: 4 MB
  • Transactional message, scheduled message, or delayed message: 64 KB
Note The size of attributes for a message of all types cannot exceed 16 KB.
The size of a message cannot exceed the maximum message size that corresponds to a message type. If the size of a message exceeds the upper limit, the message fails to be sent.
Message retention period Three days Messages can be retained for up to three days. After the retention period elapses, the system automatically deletes the messages.
Reset consumer offsets Three days Consumer offsets can be reset for messages that are sent at a point in time within three days before the most recent message in a specified topic is sent.
Transactions per second (TPS) for sending and receiving messages in a single Message Queue for Apache RocketMQ instance
  • Standard Edition: 5,000 messages/second.
  • Enterprise Platinum Edition: The value varies based on the purchased specification.
If you want to use Standard Edition instances that have higher specifications, specify your business requirements and computing logic and submit a ticket.

Standard Edition instances share physical resources. Resources are allocated based on physical limits such as the resource usage of all Standard Edition instances. As a result, not all applications are approved.

We recommend that you upgrade your instance from the Standard Edition to the Enterprise Platinum Edition to meet your business requirements.

Delay time of scheduled or delayed messages 40 days You can set the msg.setStartDeliverTime parameter for a message to a point in time that is within 40 days after the message is sent. The value is in milliseconds. The system cannot send the message after the 40-day period elapses.
Note A latency of 1 to 2 seconds occurs for scheduled messages.
Message sending in batches Not supported Message Queue for Apache RocketMQ does not allow you to send messages in batches.