Esper - handle out of order events - complex-event-processing

Question

I want to monitor if an event does NOT arrive within 10 minutes of arrival of event with the same id.
This is the EPL I am currently using:
SELECT * FROM pattern[ every s=Order_Status(status="placed") -> (timer:interval(600 sec) and not e=Order_Status(status="delivered", id=s.id))]
Usually placed event arrives before delivered, but sometime because of some lag in our systems, delivered event happens to come before placed for some id.
Cases
time: 8:00 event: Order_Status{id=167, status="placed"}
time: 8:07 event: Order_Status{id=167, status="delivered"}
< No alert > (delivered within 10 minutes)
time: 8:00 event: Order_Status{id=189, status="placed"}
time: 8:17 event: Order_Status{id=189, status="delivered"}
< Alert> (delivered after 10 minutes)
time: 8:00 event: Order_Status{id=2637, status="delivered"}
time: 8:08 event: Order_Status{id=2637, status="placed"}
< Alert > (but shouldn't alert, the problem is delivered event for this id has arrived before placed)
As stated, I would get a false alert as the EPL pattern starts the window after the placed event and waits for delivered event which has already arrived.
How do I handle this scenario of out of order events ?
Note:
(Basically I want to check for every id if the time difference between placed and delivered is above a certain threshold.
I also have the timestamp fields inside each event)

Answer 1

You have a "not" in your pattern that is used to detect the absence of events. Your requirement doesn't search for absence so the "not" isn't right.
There is a requirement questions as well. You don't state what happens when there are many A events and just one B event. Are there many matches or just the match for the last A event or the first A event or something else?
Sample pattern:
pattern [A -> (timer:interval(10 minutes) and B)]
Or this is a join that would seem to match what you want:
select * from B unidirectional, A#window(10 minutes)#lastevent
The "A#window(10 minutes)#lastevent" keeps the last event for up to 10 minutes.