The following rule produces a memory leak in Drools 6.1.0-SNAPSHOT:
/* If a RAISE is buffered for N seconds, send it out */
rule "forward raise"
$raise : MyEvent(eventState == EventState.RAISE, $raiseId : eventId)
System.out.println("Forwarding RAISE(" + $raiseId + ")");
I see the rule fire as expected, printing out the message 3 seconds after the event is
added into the session. While the event is waiting, I see a FactCount of 1 in the
session. After the rule fires, the fact count goes to 0. However, using JVisualVm,
querying the heap dump shows 1 instance of MyEvent, referenced by an EventFactHandle and
several other Drools objects.
Is this a bug, or is there a better way to write this rule so Drools’ internals let go of
the object after it is no longer a fact?