FYI for the group.  We seem to have solved our performance problem.

I'll describe our problem space a bit some people have some context.  We
load up about 1200 Jobs with about 3000 Stops and about 1500 Vehicles
with about 2000 Workers.  We then calculate Scores for each Vehicle for
each Job.  Some combinations get excluded for various reasons, but we
end up with 700k - 900k total facts.  We do score totaling and sorting
using accumulators.

One of our teams members (nice find Dan) decided to try to isolate the
accumulation rules until all our other facts are loaded.  Those rules
now have a "not ColdStarting()" condition and our startup code inserts a
ColdStarting fact as the first fact and retracts it when all the Jobs
and Workers have been loaded.  This changed our startup time from over
50 minutes to under 5.  There's some sort of strange propagation and
looping going on with accumulation on the fly, at least with our facts
and rules.

I'll put an entry on the wiki as well.

-----Original Message-----
[mailto:[EMAIL PROTECTED] On Behalf Of Fenderbosch,
Sent: Monday, June 30, 2008 11:46 AM
To: Rules Users List
Subject: RE: [rules-users] Drools 4 poor performance scaling?

We are having a similar problem, although our fact count is much higher.
Performance seems pretty good and consistent until about 400k facts,
then performance degrades significantly.  Part of the degradation is
from bigger and more frequent GCs, but not all of it.

Time to load first 100k facts: ~1 min
Time to load next 100k facts: ~1 min
Time to load next 100k facts: ~2 min
Time to load next 100k facts: ~4 min

This trend continues, going from 600k to 700k facts takes over 7
minutes.  We're running 4.0.7 on a 4 CPU box with 12 GB, 64 bit RH Linux
and 64 bit JRockit 5.  We've allocated a 9 GB heap for the VM using
large pages, so no memory paging is happening.  JRockit is started w/
the -XXagressive parameter, which enables large pages and the more
efficient hash function in HashMap which was introduced in Java5 update

The end state is over 700k facts, with the possibility of nearly 1M
facts in production.  After end state is reached and we issue a few GC
requests, if looks like our memory per fact is almost 9k, which seems
quite high as most of the facts are very simple.  Could that be due to
our liberal use of insertLogical and TMS?

We've tried performing a "commit" every few hundred fact insertions by
issuing a fireAllRules periodically, and that seems to have helped

I tried disabling shadow proxies and a few of our ~390 test cases fail
and one loops indefinitely.  I'm pretty sure we could fix those, but
don't want to bother if this isn't a realistic solution.

Any thoughts?



-----Original Message-----
[mailto:[EMAIL PROTECTED] On Behalf Of Ron Kneusel
Sent: Thursday, June 26, 2008 12:47 PM
Subject: [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

rule rule0000
        Data(type == 0, value> 0.185264);
        Data(type == 3, value < 0.198202);
        insert(new AlarmRaised(0));
        warnings.setAlarm(0, true);

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),
            en = (new Date()).getTime();
            System.out.println("    facts = " + (en-st));

            //  Now run the rules
            st = (new Date()).getTime();
            en = (new Date()).getTime();
            System.out.println("    rules = " + (en-st));

            //  Clean up


This code is based on the 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!


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