[rules-dev] Why is this DRL twice as slow? Why is calculationg from scratch faster?

[Geoffrey De Smet]

So I tried this "query from scratch each time" experiment:

query "hardConstraintsBroken"
     constraintOccurrence : IntConstraintOccurrence(constraintType == 
ConstraintType.NEGATIVE_HARD)
end
query "softConstraintsBroken"
     constraintOccurrence : IntConstraintOccurrence(constraintType == 
ConstraintType.NEGATIVE_SOFT)
end

With this java code:

         int hard = 0;
         QueryResults results = 
workingMemory.getQueryResults("hardConstraintsBroken");
         for (QueryResult result : results) {
             IntConstraintOccurrence constraintOccurrence = 
(IntConstraintOccurrence) result.get("constraintOccurrence");
             hard += constraintOccurrence.getWeight();
         }
         int soft = 0;
         results = workingMemory.getQueryResults("softConstraintsBroken");
         for (QueryResult result : results) {
             IntConstraintOccurrence constraintOccurrence = 
(IntConstraintOccurrence) result.get("constraintOccurrence");
             soft += constraintOccurrence.getWeight();
         }


That takes 118s.
So it's clearly faster than the merged rule DRL!
It's not faster than the original accumulate DRL.
- original DRL: 71s
- query from scratch each time: 118s
- merged rule DRL: 172s

So calculating everything from scratch each time (and fetching it from 
the QueryResult Map) is faster than using 2 accumulate.

With kind regards,
Geoffrey De Smet


Geoffrey De Smet schreef:
> 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?
>