Hi everyone, I have a keyed stream which is expecting events every fixed interval (let's say 1 minute). I want to raise alarms for any key which has received no events in n-periods. What should be the cheapest way (in term of performance ) to do this? I thought of some solutions, but don't know which one is the best: 1. Sliding window then count the number of events in each window <<< this seems quite expensive when n is big. 2. Register a timer for every single event, record the last event timestamp and check that timestamp when the timer expires. (This would be the best if there's an option to cancel/modify a timer, but it seems that feature is not available yet) 3. Session window: i haven't implemented this to verify its feasibility. Thinking of firing the alarm on every window clear event. 4. CEP. I don't know whether it's possible or not. Haven't found a guide for defining patterns of missing events.
Could you please give some advices? Thanks and best regards, Averell -- Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/
