Adam, There are several ways to deal with large number of rules. For example, instead of re-compiling the whole rule set every time, you could just compile the rules that are updated/new, then adding them to the existing KnowledgeBase instance. Drools is capable to handle such usage, even during rule execution - but would not recommend to do that. API's are also available to remove packages, rules, etc. We are using something similar for generated rules. It is also important to note that it would require persisting the KnowledgeBase so it could be reloaded after restarting the application. Just a thought. -Ming From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Adam Sussman Sent: Wednesday, September 02, 2009 7:21 PM To: rules-users(a)lists.jboss.org Subject: [rules-users] Scaling to large numbers of rules I am hoping that I am doing something wrong here and that one of you can point me in the right direction. Can anyone provide some advice on scaling up the number of rules in a single KnowledgeBase? While I have seen all sorts of reports on having lots of facts, I have not seen anything about having lots of rules. I need to get to about 200K rules in a single KnowledgeBase, and also to run several of these side by side in the same system. The problem: As the number of rules increases, the time to compile and load them into memory skyrockets. Now while I realize that the Rete algorithm complexity is about the number of rules, the times I am seeing are pretty scary. Also, at about 30k rules, things just fall apart. On a 64 bit Linux OS with 2 2.4Ghz processors using a 64bit JVM from OpenJDK (1.6.1) with 1 Gig of memory allocated to the JVM, loading from .drl files: 1000 rules: KnowledgeBuilder.add: 7 seconds KnowledgeBase.addKnowledgePackages: .8 seconds 10000 rules: KnowledgeBuilder.add: 79 seconds KnowledgeBase.addKnowledgePackages: 23 seconds 15000 rules: KnowledgeBuilder.add: 138 seconds KnowledgeBase.addKnowledgePackages: 55 seconds 20000 rules: KnowledgeBuilder.add: 488 seconds KnowledgeBase.addKnowledgePackages: 100 seconds 30000 rules: KnowledgeBuilder.add: out of memory KnowledgeBase.addKnowledgePackages: never runs At this rate, 200k rules will take 13-14 hours to compile and 2-3 hours to load into RAM, assuming I can even get to that many rules. This just is not usable. Time to fire all rules is negligible (fortunately!). The rules I am testing on are very simple 1-3 variable equality whens with a simple System.out.println then clause. The benchmark code I am running is as follows: KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(); KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); kbuilder.add( ResourceFactory.newClassPathResource( drlFile, RuleRunner.class ), ResourceType.DRL ); Collection<KnowledgePackage> pkgs = kbuilder.getKnowledgePackages(); kbase.addKnowledgePackages( pkgs ); Sample rule: rule "00000005 - random rule" when Transaction(someId == 35156 && someOtherId == '79F81FB8134A129F' && someCollection contains 'EC3F2A1DCA88') then System.out.println("match rule 00000005 - random rule"); end Any help would be appreciated. Regards, Adam Sussman CONFIDENTIALITY NOTICE: This message contains information which may be confidential or privileged. If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this information is prohibited. If you have received this transmission in error, please notify me immediately by telephone.

If your 200K rules are all of the same few patterns (1, 2 and 3 attribute equalities) then expanding this into all combinations may not be the way to go. Can you provide a little more detail about whether the 1/2/3 attributes are always from the same fact type, and how many of these 1-2-3-combinations there are? Also, combinations of rules and (hash) lookup tables might reduce the number of rules by several orders of magnitude. -W 2009/9/3 Adam Sussman <adam.sussman(a)ticketmaster.com&gt;