To reproduce:
1) Create a Hello World sample application (Drools Eclipse Plugin)
2) Replace Sample.drl with:
declare Message
@role(event)
end
rule "Hello World"
when
m : Message( myMessage : message )
then
System.out.println( myMessage );
end
//counts numbers of events in the previous 3 seconds
rule "slidingTimeCount"
when
$n: Number (intValue > 0) from accumulate ( $e : Message() over window:time(3s) , count($e))
then
System.out.println("Messages in last 3 seconds: " + $n);
end
3) Add this constructor to the Message class:
public Message(String m)
{
this.message = m;
}
4) In Main Method replace everything between //go and logger.close(); with:
for(int i=1;i<3;i++)
{
Thread.sleep(1001);
Message message = new Message("Hello" + i);
ksession.insert(message);
System.out.println(i + ". rule invocation");
ksession.fireAllRules();
}
Thread.sleep(3001);
Message lateMessage = new Message("Hello 3");
ksession.insert(lateMessage);
System.out.println(3 + ". rule invocation");
ksession.fireAllRules();
Thread.sleep(3001);
Message lateMessage2 = new Message("Hello 4");
ksession.insert(lateMessage2);
System.out.println(4 + ". rule invocation");
ksession.fireAllRules();
--> Run: The output will be:
1. rule invocation
Messages in last 3 seconds: 1
Hello1
2. rule invocation
Hello2
Messages in last 3 seconds: 2
3. rule invocation
Messages in last 3 seconds: 1
Hello 3
Messages in last 3 seconds: 1
4. rule invocation
Messages in last 3 seconds: 1
Hello 4
--> After "5. rule invocation" the sliding-window rule fires 2x -> it should only fire once!
More info:
- if sleep time of thread is < 2997 in any Thread.sleep() after the loop, rule is not fired twice
- bug also appears when working with SessionPseudoClock.advanceTime() instead of Thread.sleep() (also when t > 2997)
- bug appears in STREAM mode and CLOUD mode
The bug has some more quirks, e.g. somehow the condition in the erroneous firing rule seems not to work properly. For more information about the bug read this thread: http://drools.46999.n3.nabble.com/Getting-data-from-a-database-My-SQL-to-Guvnor-tt4025814.html#a4025870 (from post #2, thread was unintentionally hijacked)
Bug
Major
