Sorry for the delay in getting to this. Very interesting idea. A couple of notes:

• This would have to be done with commit timestamps, not checkpoint timestamps, because checkpoint construction and execution are asynchronous. But the overall idea would be the same.
• I think this could be added as an extension to the system Clock object relatively easily.

The proposed sliding mechanism window is efficient in theory, but will be somewhat difficult to implement due to crash recovery requirements.

As an alternative, what if we exposed exponential moving averages for a handful of different α values? (say 0.1, 0.01, and 0.001)?