[rules-dev] Why is this DRL twice as slow?

[Geoffrey De Smet]

Hi guys,

I've run some experiments on the DRL's used in the drools solver 
examination example to see how the DRL affects performance.

In one experiment, I merged 2 rules into 1 rule:

I changed this DRL part of examinationScoreRules.drl:

rule "hardConstraintsBroken"
         salience -1
     when
         $hardTotal : Number() from accumulate(
             IntConstraintOccurrence(constraintType == 
ConstraintType.NEGATIVE_HARD, $weight : weight),
             sum($weight)
         );
     then
         scoreCalculator.setHardConstraintsBroken($hardTotal.intValue());
end

rule "softConstraintsBroken"
         salience -1
     when
         $softTotal : Number() from accumulate(
             IntConstraintOccurrence(constraintType == 
ConstraintType.NEGATIVE_SOFT, $weight : weight),
             sum($weight)
         );
     then
         scoreCalculator.setSoftConstraintsBroken($softTotal.intValue());
end



into this DRL part:

rule "constraintsBroken"
         salience -1
     when
         $hardTotal : Number() from accumulate(
             IntConstraintOccurrence(constraintType == 
ConstraintType.NEGATIVE_HARD, $weight : weight),
             sum($weight)
         );
         $softTotal : Number() from accumulate(
             IntConstraintOccurrence(constraintType == 
ConstraintType.NEGATIVE_SOFT, $weight : weight),
             sum($weight)
         );
     then
         scoreCalculator.setHardConstraintsBroken($hardTotal.intValue());
         scoreCalculator.setSoftConstraintsBroken($softTotal.intValue());
end


Now the performance for a 100 steps when from 71s to 172s, so it more 
then doubled.
All other code stayed the same and the output (except for the times) is 
exactly the same.
What can explain this loss in performance?

-- 
With kind regards,
Geoffrey De Smet