Restrictions on request data rate
- Last UpdatedMar 20, 2025
- 1 minute read
- PI System
- PI Web API 2023 SP1 Patch 1
- Developer
You can limit the rate at which clients request data by setting rate limit parameters in the Configuration database.
The following configuration items are available in PI Web API:
RateLimitMaxRequests
The maximum number of requests per client (identified by IP address) over a specified duration of time. Add or set the configuration item in PI System Explorer:
|
Field |
Description or value |
|---|---|
|
Value Type |
Int32 |
|
Value |
Enter a numeric string that represents the maximum number of requests per client. Minimum value is 1. Maximum value is 2,147,483,647. The default value is 1,000. |
RateLimitDuration
The period of time, in seconds, that the client is limited to a specific number of requests. Add or set the configuration item in PI System Explorer:
|
Field |
Description or value |
|---|---|
|
Value Type |
Int32 |
|
Value |
Enter a numeric string that represents the number of seconds per client. Minimum value is 1. Maximum value is 2,147,483,647. The default value is 1. |
The rate limit per client IP address is calculated with the formula:
Rate limit per second per IP = RateLimitMaxRequests / RateLimitDuration
With default parameter values, this limit resets every single second, meaning that a maximum of 1000 requests can be made per second.
If the rate limit is reached or exceeded, a response is returned with HTTP status 429 (Too Many Requests). The response body contains the following error message:
Rate limit was reached