Using nanosecond precision in the PromQL HTTP API

[nicecui]

What type of enhancement is this?

API improvement

What does the enhancement do?

The documentation said:

The timestamp precision in PromQL is limited by its query syntax, only supporting calculations up to millisecond precision. However, GreptimeDB supports storing high-precision timestamps, such as microseconds and nanoseconds. When using PromQL for calculations, these high-precision timestamps are implicitly converted to millisecond precision.

Since GreptimeDB supports high-precision timestamps, it is better for the API endpoints to use nanosecond as the default precision to avoid loss of precision.

Implementation challenges

No response