In an attempt not to hijack your thread...again...I have a similar experience to you on recalculation
At the time (about 4, 5 years ago) I wrote an application that performed some calculations and it too uses a "last run time" data item to indicate when calculations last ran, and it always calculates forward from that point in time. In assumes there is some buffering of data from interfaces if PI is down or an interface is down. It also allows users to "rewind" calculations if they want to alter inputs. This was built for a specific set of calculations (still a unique set of calculations within that client ) but the principles were lifted to quite a few other applications. Since then things are getting a lot better with off the shelf calculations/analytics and when running cases/analysis or eventually event frames becomes a 'permanently exposed feature' () within AF it will tick some more boxes from my perspective. Being able to make adjustments to case data and re-run a case is a great option in a lot of scenarios.
The one part of ACE I would still like to see is a more "business user" friendly method of managing/reviewing/altering calculations, possibly with some workflow & approval steps (especially as we now get WIS on the PI server and AF) - rather than relying on having Visual Studio installed etc...I saw one client's attempt to tackle this, it was quite a good solution that gave business users a sandbox to test calculations before submitting them for production.
Thankyou for commenting and providing input, internally we have these documented (and now updated from your input!) as
1. Recalculation - A) above - User wants to rerun analytics based on changes to the input data
2. History Recovery - Run analytics for period of time the analytic scheduler was offline
3. Out of order event processing - Input data for analytics is time stamped prior to events already processed
B) and C) are scenarios that would appear to fit in with the second and third entries above or would be handled by the normal operation of a scheduler
Point about user running the recalculation also noted
As for recalculation today
- there is the recalculator for Performance Equations
- ACE supports recalculation