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. |