[rules-users] Performance issues with a rule that includes LHS functions

I have a rule that is suffering severe performance degradation as I insert facts into the (stateful) session. In my simplified example, the first 100 fact insertions take less than 10ms per fact. By the 1000th fact, insertions are taking about 850ms per fact. In production, the impact is much more severe, reaching 5000ms or more by the 1000th insertion. The number of facts per execution can vary from a few hundred to a few thousand. I've created a simplified example that demonstrates the problem: Imagine that there is a line plotted through a 3-dimensional plane and it is necessary to ensure that each plotted coordinate is an equal distance from the adjacent coordinates. I realize that the math isn't correct, but it is sufficient for the example. The constraint (and source of performance degradation) imposed by my data source is that the plane (X, Y, or Z) is variable and it is defined by an separate index that serves as a pointer into the coordinate list. If I remove the function calls, the problem disappears. Any suggestions on how I could rewrite the rule? Here is my rule: package test; declare Data plane : int coordinates : java.util.List end rule "Performance degradation with functions." dialect "mvel" when $current : Data( $currentPosition : getPosByAxis(plane, coordinates) ) $before : Data( $beforePosition : getPosByAxis(plane, coordinates) < $currentPosition) not Data( getPosByAxis(plane, coordinates) > $beforePosition && < $currentPosition) $after : Data($afterPosition : getPosByAxis(plane, coordinates) > $currentPosition) not Data(getPosByAxis(plane, coordinates) < $afterPosition && > $currentPosition) eval ( ($currentPosition - $beforePosition) == ($afterPosition - $currentPosition) ) then System.out.println("Rule RHS fired."); end function Double getPosByAxis(int plane, java.util.List coordinates) { return (Double) coordinates.get(plane); } Thanks, Mike Goldner