This topic describes the limits on some parameters and metrics in Message Service (MNS). To prevent application exceptions, make sure that the limits of the parameters and metrics are not exceeded when you use MNS.
The following table describes the limits on MNS queues.
Item | Limit | Description |
Name length | 120 characters | If this limit is exceeded, the queue fails to be created. |
Number of queues | 1,000 | None. |
Message size | 64 KB | If this limit is exceeded, 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 a message retention period based on your needs. After the specified period expires, the message is deleted. |
Queries per second (QPS) for a single queue | 3000 | When you call the BatchSendMessage operation to send requests to a queue, the BatchSendMessage QPS can be calculated based on the following formula: QPS = Number of BatchSendMessage requests per second × Number of messages. Assume that you call the BatchSendMessage operation to initiate 100 requests in one second to send 10 messages, the QPS of a single queue is calculated based on the following formula: 100 × 10 = 1000. |
The following table describes the limits on MNS topics.
Item | Limit | Description |
Name length | 120 characters | If this limit is exceeded, the topic fails to be created. |
Number of topics | 1,000 | None. |
Message size | 64 KB | If this limit is exceeded, the message is discarded. |
Number of subscriptions to a single topic | 100 | None. |
Message retention period | 1 day | We recommend that you specify a 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. |
The QPS for a single queue and QPS for a single topic items in the preceding tables indicate the QPS of API operations. To extend the QPS limits, submit a ticket.