Restrictions

VPC/subnet/AZ

Fixed once the instance is created.

Request-Reply

Not supported.

Configuration parameters

Cannot be modified using open-source APIs.

Maximum number of topics

Depends on the instance specifications. This limit cannot be changed.

When this limit is reached, no more topics can be created.

Automatic topic creation

Not supported.

Broker faults

When some brokers of an instance are faulty, topics cannot be created, modified, or deleted, but can be queried.

Maximum number of consumer groups

Depends on the instance specifications. This limit cannot be changed.

When this limit is reached, no more consumer groups can be created.

Creating consumer groups, consumers, and producers

Consumer groups, consumers, and producers are generated automatically when you use the instance.

Consumer offset reset

You can reset the retrieval start position to any time within two days.

Resetting the consumer offset

Messages may be consumed more than once after the offset is reset.

Broker faults

When some brokers of an instance are faulty, consumer groups cannot be created, modified, or deleted, but can be queried.

Message retention duration

The default retention period is 48 hours, which can be modified to up to 720 hours. Messages will be automatically deleted after the retention period expires.

Message size

The maximum size of a message is 4 MB. The maximum size of a message attribute is 16 KB. The message size cannot be changed.

When this limit is reached, messages will fail to be sent.

Delay of scheduled messages

The maximum delay is one year. This limit cannot be changed.

You can schedule messages to be delivered at any time within one year.

Number of users

A maximum of 1000 users can be created for a RocketMQ instance.

Broker faults

When some brokers of an instance are faulty, users cannot be created, modified, or deleted, but can be queried.