Hello All, I have a temporal pattern and I'm wondering what's the best way to find something like: *stream of messages of type A and B search for B and give me 5 immediate occurrences of A or B which happened before B.* example: A,A,A,B,B,A,B,A,B,A,A,A,A,A,B,A should give me: A,A,A|B A,A,A,B|B A,A,B,B,A|B B,B,A,B,A|B A,A,A,A,A|B So I made a pattern like: $e1 : Event( type== A || type == B) from entry-point "Stream" $e2 : Event( type== A || type == B, this after[1ms,1m] $e1) from entry-point "Stream" $e3 : Event( e type== A || type == B, this after[1ms,1m] $e2) from entry-point "Stream" $e4 : Event( type== A || type == B, this after[1ms,1m] $e3) from entry-point "Stream" $e5 : Event( type== A || type == B, this after[1ms,1m] $e4) from entry-point "Stream" $e : Event( type== B, this after[1ms,1m] $e5 ) from entry-point "Stream" not( Event( type== A || type == B, this after $e1, this before $e2) from entry-point "Stream" ) not( Event( type== A || type == B, this after $e2, this before $e3) from entry-point "Stream" ) not( Event( type== A || type == B, this after $e3, this before $e4) from entry-point "Stream" ) not( Event( type== A || type == B, this after $e4, this before $e5) from entry-point "Stream" ) not( Event( type== A || type == B, this after $e5, this before $e) from entry-point "Stream" ) I also put the time constraint for more constraint search, but the search is quite slow plus the memory is exploding very fast - several GB in few seconds. I also tried to accumulate last 5 events using a floating window, which helped a lot with performance, but if I would be interested to have only A preceding B, then it wouldn't help. Can you pls help me understand what is the best practice to define a drool pattern for the one I described above? Thanks a lot! Michal -- View this message in context: http://drools.46999.n3.nabble.com/drools-memory-explosion-for-quite-simpl... Sent from the Drools: User forum mailing list archive at Nabble.com.