RocketMQ is a high-performance, highly reliable, and scalable distributed message queuing system, but there are some usage limitations, as shown in the following table:

Item	Exemption
Topic Name	A name contains 2 to 64 characters and will fail to be created if it exceeds the length limit. A user-created topic can only consist of uppercase and lowercase letters, numbers, underscores (_) and hyphens (-).
Group Name	A name contains 2 to 64 characters and will fail to be created if it exceeds the length limit. A user-created subscription group can only consist of uppercase and lowercase letters, numbers, underscores (_) and hyphens (-).
AccessKey	The AccessKey that is created in role management of the advanced engine version must contain 2 to 64 characters, including uppercase and lowercase letters, numbers, and underscores (_).
SecretKey	The SecretKey that is created in role management of the advanced engine version must contain 8 to 64 characters, including uppercase and lowercase letters, numbers, and special characters (!@#$%).
Delivery Time of Delayed Messages	The longest delay is 40 days. If the delay exceeds 40 days, the transmission fails.
Message Size	The maximum size for normal and ordered messages is 4MB and that of the delayed messages is 16KB. Exceeding this limit will result in message sending failures. If the limit is exceeded, messages will fail to be sent.
Message Storage Duration	The longest message storage duration is three days, and messages exceeding the maximum storage duration will be deleted.

Distributed Message Service RocketMQ

Limitations