Automatically archive historical data and provide downsampling capabilities

[killme2008]

What type of enhancement is this?

API improvement, User experience

What does the enhancement do?

Detailed metrics or log data have relatively high storage costs.
Typically, after exceeding the TTL or a certain period, the data can be downsampled to reduce storage costs.
For example, only storing error-level logs or aggregating millisecond-level data into minute-level data using specified aggregation functions can further reduce the storage cost of historical data while continuing to provide valuable historical data queries.
If GreptimeDB could offer the ability to create archiving tasks with customizable archiving rules and calculations, it would be very convenient.

Implementation challenges

No response