Re: [rules-dev] Why is this DRL twice as slow?
As I understand it, the from keyword is not optimized in the way that it's output is
not indexed. Therefore if the set of objects matched changes it must rerun. So when you
have the two rules, "hardConstraintsBroken" is reevaluated when you change the
hard constraints, and "softConstraintsBroken" is reevaluated when you change the
soft constraints. When there's just the one rule, it's reevaluated when either
the hard or soft constraints changed, but BOTH accumulate expressions are evaluated every
time. Thus, 2x the evaluation time.
--- On Sat, 8/8/09, Geoffrey De Smet <ge0ffrey.spam(a)gmail.com> wrote:
From: Geoffrey De Smet <ge0ffrey.spam(a)gmail.com>
Subject: [rules-dev] Why is this DRL twice as slow?
To: rules-dev(a)lists.jboss.org
Date: Saturday, August 8, 2009, 5:46 AM
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
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