Hi, I've been building a BRMS server over the Drools 4MR2 API. The Server has a Boot process to allow to make it become a Rule server(s). reads and XML configuration in which a user can specify the location of the DRL, XLS, CVS, etc. During the Boot proocess it verifies thew authenticity of each resource it loads. To sommarize: <Session 1 type="Stateless"> <Rule Source 1> <Rule Source 2> .. <Adapter ExternalService class="..."/> <Session> <Session 2 type="Stateful"> <Rule Source 1> <Rule Source 2> .. <Session> ..well its more, but I guess this paints the picture. It creates a Pool of Sessions. Now I know creating a Session is inexpensive, but the process of creating them and authentication of resources etc. (Required for prodcution quality system) Once the server is up, requests are serviced. the request knows which session it wants and facts are asserted per request. The request can be Synchronous or Async and single or batch. For testing I'm using: (JMeter test Case) Session mode: STATELESS Synchronous Mode: Batch of 5 facts (composing of other objects (about 5) which are asserted into the Session as well) at at a time Loop: 10,000 <-- Does not matter how fast or slow I trow this at the engine After the request is processed and results logged; Result and what rules led to that result. I even nullify the top level Business obejcts. (a desperate attempt to free memory) After about 10,000 loops the System goes out of memory. Sorry to bore you so far, but it was important you have the right context :o) QUESTION:: Is the session maintaining references to those objects ever after executing them? Why are the objects not being released? Specially I'd imagine for a STATELESS session (which is what I've set as default). Using JMeter this system crashes every time under load, even with a single Thread. Clearly objects are not being released. The error I get may help you: (Along with out of memory). This exception only comes under Load conditions. Admin:ERROR: [com.myserver.brms.demos.certify.web.servlet.CertifyWebRequests] [service] :org.drools.spi.ConsequenceException: java.lang.NullPointerException at org.drools.common.DefaultAgenda.fireActivation (DefaultAgenda.java:501) at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:461) at org.drools.common.AbstractWorkingMemory.fireAllRules (AbstractWorkingMemory.java:373) at org.drools.reteoo.ReteooStatelessSession.execute (ReteooStatelessSession.java:72) at com.myserver.brms.sessions.RulesEngineSessionJBossRules4.execute (RulesEngineSessionJBossRules4.java:113) at com.myserver.brms.services.execute.recore.batch.ExecuteSessionBatch.executeBatch (ExecuteSessionBatch.java:160) Please help me! This is the only downtime issue I face and unfortunatley its the most critical point of failure. All thats left is to build an RMI service with a console dameon shell to give it the final touches. Once this is done i'd like to share the deisng with you guys if you like it. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

> QUESTION:: Is the session maintaining references to those objects ever after > executing them? Why are the objects not being released? > > Specially I'd imagine for a STATELESS session (which is what I've set as > default). > > Using JMeter this system crashes every time under load, even with a single > Thread. Clearly objects are not being released. > > The error I get may help you: (Along with out of memory). This exception only > comes under Load conditions. > Admin:ERROR: [com.myserver.brms.demos.certify.web.servlet.CertifyWebRequests] > [service] :org.drools.spi.ConsequenceException: java.lang.NullPointerException > > at org.drools.common.DefaultAgenda.fireActivation > (DefaultAgenda.java:501) > > at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:461) > > at org.drools.common.AbstractWorkingMemory.fireAllRules > (AbstractWorkingMemory.java:373) > > at org.drools.reteoo.ReteooStatelessSession.execute > (ReteooStatelessSession.java:72) > > at com.myserver.brms.sessions.RulesEngineSessionJBossRules4.execute > (RulesEngineSessionJBossRules4.java:113) > at > > com.myserver.brms.services.execute.recore.batch.ExecuteSessionBatch.executeBatch > (ExecuteSessionBatch.java:160) > > Please help me! This is the only downtime issue I face and unfortunatley its > the most critical point of failure. > Ok, I think I figured it out. But please confirm. The Rule Engine Session DOES NOT release objects. (But hten why have a Stateless session?) if the duration of use of the session is not going to be long? The solution: Pool the RuleBase and on a request createa freesh session from it each time a request comes in! Let me know if the cocept is sound or what I'm thinking is now correct. Thanks, Arjun _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

> Stateless sessions should not hold onto any references. Stateful do, > and dispose() must be called when its finished - otherwise the rulebase > holds a reference forever. If the rulebase is holding onto stateless > sessions, then that is a bug. > Mark > Thanks a lot Mark, taking the latest binary passed the load testing one a single thread atleast. Though I need to confirm due to removal of "modify()" none of the functionality has got altered. It chokes a little in the middle but is not going out of memory so I guess the leak is really fixed. One last question on this: On the Build 4MR2, I disposed the session and created a new one from the cached RuleBase and it took the load (on the code that had the memory leak) So what approach is conceptually better; Keep the same statless session for ever or for each execution request use a new one?? I talking pure performance/memory?!?! I remember you saying creating sessions is cheap; so if I have a million requests and for each one I create a new session is it still cheap? or a single stateless session servicing the requests is better? Typical Application: telephone exchange; where numbers are bombarding the engine. For each incomming request I'd assume a single session would be the most optimal solution as long as the rules are common. Right?! I'm wondering if I should also maintain an image, object = {RuleBase + Globals} so I can create a session. but I think this would have a huge performance cost to create new sessions per request. Right? Thanks for the Fix, its life saver! Thanks, Arjun _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users