Simple Message Queue (SMQ, formerly MNS) supports throttling policy feature to allow you to specify the maximum number of concurrent requests. This helps prevent underlying resources from being overwhelmed by traffic surges and ensure high reliability and availability of backend services.
Throttling behavior
If the number of requests exceeds the throttling threshold, the SMQ system starts the backpressure mechanism. In this case, the requests are returned after being suspended for about 500 milliseconds. This helps ensure system reliability and stability.
Error codes
The following error code is returned when the throttling policy is triggered.
HTTP status code | Error code | Description |
429 | TooManyRequests | The request is denied by cluster flow limiter for too many requests. |
Throttling description
If you require a higher throttling threshold for a specific operation, submit a ticket.
Category | Throttling threshold for each Alibaba Cloud account in each region | Calculation method | Operation |
Data stream messaging | 20,000 QPS | If you call the BatchSendMessage operation to send requests to a queue, the queries per second (QPS) of BatchSendMessage can be calculated based on the following formula: QPS = Number of BatchSendMessage requests per second × Number of messages. For example, if you call the BatchSendMessage operation to initiate 100 requests in 1 second to send 10 messages, the QPS of a single queue is calculated based on the following formula: 100 × 10 = 1000. | |
Metadata | 200 QPS | Each time a request is sent, the number of QPS is increased by 1. |