In my case, I use Flink's queryable state only. In particular, I do not care about checkpoints.
Upon an event, I query the queryable state only after a maximum of X minutes. Ideally, I would delete the "old" state to save on space.
That's why I wonder: can I signal Flink's state to clear itself after some time? Through configuration? Through specific event signals? How?
One way to clear state is to explicitly call clear() on the state object (e.g., a ValueState object) when you no longer need it for a particular key. This is typically done in an onTimer() callback in a ProcessFunction.
Another possible approach would be to use state time-to-live to manage its lifecycle.
I haven't tried using state TTL with queryable state, but I can't see any reason why it shouldn't work. However, as of Flink 1.7, state TTL only actually clears state (for a key) when the state is accessed (for that key), or when taking a full state snapshot. So in your particular case, this state TTL mechanism may not be very useful.
