Re: [rules-users] Drools stateless session question

It will be 1 trillion activations unless there is an index on the "id" property of the classes. If the right index is used, it should scan all objects of one class, and through indexes figure out the corresponding related objects of other classes. I am not sure if we can somehow tell rete to create indexes on certain attributes. I read a nice article on indexing in drools, which mentioned about Rete Beta node indexing. I am not sure if this is what drools is doing internally. Any suggestions/ideas? http://blog.decaresystems.ie/index.php/2008/02/24/rete-nodes-indexing-in-... Thanks, Malay ________________________________ From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Wolfgang Laun Sent: Monday, March 22, 2010 3:17 PM To: Rules Users List Subject: Re: [rules-users] Drools stateless session question You have calculated it correctly: 10000 A's * 10000 B's * 10000 C's results in 1,000.000,000.000 activations, which is (almost) a mind-boggling figure. I can't imagine what benefit this trillion of activations is going to have for your application. Even if you have the memory for all that, assuming that firing of one of these activations and processing of the RHS statements can be done in one microsecond, this is going to take days to complete, and it'll create a huge data set of A/B/C combinations for just this one rule. Are you sure that you are on the right track?! -W On Mon, Mar 22, 2010 at 7:46 PM, Shah, Malay <Malay.Shah@morganstanley.com<mailto:Malay.Shah@morganstanley.com>> wrote: Thanks W. Let me give you a rule that is causing us issues. Lets say we have classes: class A { int a; String id; } Class B { int b; String id; } Class C { int c; String id; } and we have 12000 objects each. These objects are connected using "id" property. If the rule is something like: Rule "ABC" When Obj_A: A(a!=1) //10000 object "A" instances have a!=1 Obj_B: B(b!=2,Obj_A.id = id) //10000 object "B" instances have b!=2 Obj_C: C(c!=3,Obj_B.id = id) //10000 object "C" instances have c!=3 Then System.out.println("Rule fired"); End This means there would be a join between A, B and C objects (10000 A's * 10000 B's * 10000 C's) to evaluate the rule. In such cases, we see very high org.drools.reteoo.LeftTuple object count while profiling the app. Is there a way to make the rete algo perform this evaluation serially, or in batches, or use some object swapping mechanism to limit creation of intermediate LeftTuple objects? Would the rete algo use indexes in this case? That would potentially decrease these intermediate objects. Currently, we use 5G heap and that is not enough for evaluating this rule. Regards, Malay -----Original Message----- From: rules-users-bounces@lists.jboss.org<mailto:rules-users-bounces@lists.jboss.org> [mailto:rules-users-bounces@lists.jboss.org<mailto:rules-users-bounces@lists.jboss.org>] On Behalf Of Wolfgang Laun Sent: Monday, March 22, 2010 12:39 PM To: Rules Users List Subject: Re: [rules-users] Drools stateless session question You have misunderstood the documentation. All eight items in the enumeration you cite from are steps performed internally by the Drools engine. The only thing you have to do is request sequential mode. Without an idea about the rule set you are using it's difficult to advise how to reduce memory consumption. -W 2010/3/22 Shah, Malay <Malay.Shah@morganstanley.com<mailto:Malay.Shah@morganstanley.com>>: _______________________________________________ rules-users mailing list rules-users@lists.jboss.org<mailto:rules-users@lists.jboss.org> https://lists.jboss.org/mailman/listinfo/rules-users -------------------------------------------------------------------------- NOTICE: If received in error, please destroy, and notify sender. Sender does not intend to waive confidentiality or privilege. Use of this email is prohibited when received in error. We may monitor and store emails to the extent permitted by applicable law. _______________________________________________ rules-users mailing list rules-users@lists.jboss.org<mailto:rules-users@lists.jboss.org> https://lists.jboss.org/mailman/listinfo/rules-users -------------------------------------------------------------------------- NOTICE: If received in error, please destroy, and notify sender. Sender does not intend to waive confidentiality or privilege. Use of this email is prohibited when received in error. We may monitor and store emails to the extent permitted by applicable law.