This topic describes the limits when you use MNS.

The following table lists the limits on MNS queues.

Item Limit Description
Name length 120 characters If the name of a queue reaches this limit, the queue fails to be created.
Number of queues 1,000 None.
Message size 64 KB If the size of a message reaches this limit, the message is discarded.
Batch operations on messages 16 None.
Long polling 30 seconds None.
Message retention period 7 days We recommend that you specify the message retention period based on your needs. After the specified period expires, the message is deleted.
Queries per second (QPS) for a single queue 3,000 None.

The following table lists the limits on MNS topics.

Item Limit Description
Name length 120 characters If the name of a topic reaches this limit, the topic fails to be created.
Number of topics 1,000 None.
Number of subscriptions to a single topic 100 None.
Message retention period One day We recommend that you specify the message retention period based on your needs. After the specified period expires, the message is deleted.
QPS for a single topic 500 None.
Message filtering tag 1 A message filtering tag can be up to 16 characters in length.