I would like to set the TTL of the state in a processwindowfunction. This state is shared across windows. This TTL needs to be based on an attribute in the event itself. So I cannot calculate the TTL in the state descriptor. Also, onTimer function is not supported in processwindowfunction.
Is there any other way to achieve this?
If the time-to-live must be computed as a function of the event itself, then you can't use the state TTL mechanism.
The only alternative is to use timers with a KeyedProcessFunction, rather than using the window API. There's an example in the flink documentation: https://ci.apache.org/projects/flink/flink-docs-stable/learn-flink/event_driven.html#example