[rules-users] Drools 4 poor performance scaling?
I am testing Drools 4 for our application and while sequential mode is very fast I get
very poor scaling when I increase the number of facts for stateful or stateless sessions.
I want to make sure I'm not doing something foolish before deciding on whether or not
to use Drools because from what I am reading online it should be fast with the number of
facts I have.
The scenario: I have 1000 rules in a DRL file. They are all of the form:
rule rule0000
when
Data(type == 0, value> 0.185264);
Data(type == 3, value < 0.198202);
then
insert(new AlarmRaised(0));
warnings.setAlarm(0, true);
end
where the ranges checked on the values and the types are randomly generated. Then, I
create a Stateful session and run in a loop timing how long it takes the engine to fire
all rules as the number of inserted facts increases:
// Run
for(j=0; j < 100; j+=5) {
if (j==0) {
nfacts = 1;
} else {
nfacts = j;
}
System.out.println(nfacts + ":");
// Get a working memory
StatefulSession wm = ruleBase.newStatefulSession();
// Global - output
warnings = new Alarm();
wm.setGlobal("warnings", warnings);
// Add facts
st = (new Date()).getTime();
for(i=0; i < nfacts; i++) {
wm.insert(new Data(rand.nextInt(4), rand.nextDouble()-0.5));
}
en = (new Date()).getTime();
System.out.println(" facts = " + (en-st));
// Now run the rules
st = (new Date()).getTime();
wm.fireAllRules();
en = (new Date()).getTime();
System.out.println(" rules = " + (en-st));
// Clean up
wm.dispose();
System.out.println("\n");
}
This code is based on the HelloWorldExample.java code from the manual and the setup for
the rule base is the same as in the manual. As the number of facts increases runtime
increases dramatically:
facts -- runtime (ms)
10 -- 168
20 -- 166
30 -- 344
40 -- 587
50 -- 1215
60 -- 1931
70 -- 2262
80 -- 3000
90 -- 4754
with a maximum memory use of about 428 MB RAM. By contrast, if I use sequential stateless
sessions, everything runs in about 1-5 ms.
Is there something in my set up that would cause this, or is this how one would expect
Drools to scale? I read about people using thousands of facts so I suspect I'm
setting something up incorrectly.
Any help appreciated!
Ron
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