[rules-users] RES: Drools locking threads

[Stephen Masters]

My pleasure - I'm glad it helped. But I'd recommend being very thorough in your testing now … 5.5 is quite a big step up from 5.2! :)


On 28 Jan 2013, at 13:26, Nelio Alves Pereira Filho <npereira at cielo.com.br> wrote:

> Hello Stephen
>  
> Your suggestion improved a lot the performance, but after a while the application still started to execute poorly.
>  
> After more analysis, we identified that there was a memory leak behavior in Drools 5.2. I upgraded to the 5.5 version and the performance now is fantastic.
>  
> Tks
>  
>  
> De: rules-users-bounces at lists.jboss.org [mailto:rules-users-bounces at lists.jboss.org] Em nome de Stephen Masters
> Enviada em: terça-feira, 22 de janeiro de 2013 15:57
> Para: Rules Users List
> Assunto: Re: [rules-users] Drools locking threads
>  
> Hi there,
>  
> If I understand correctly, you're creating the stateless knowledge session once and then providing access to execute it from multiple threads. That's not going to work too well … especially on 5.2. For each request using a stateless knowledge session you should call kbase.newStatelessKnowledgeSession()
>  
> i.e. Create the knowledge base once, but create a session for each request.
>  
> Steve
>  
>  
> On 22 Jan 2013, at 15:14, nalvesp <npereira at cielo.com.br> wrote:
> 
> 
> I need some support with Drools. I'm using Drools 5.2 in a multi-threaded
> environment. Basicaly, every login into a website is calling an execute
> method in a StatelessKnowledgeSession. After some time, threads start to
> lock as below:
> 
> "[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default
> (self-tuning)'" id=18 idx=0xc0 tid=7267 prio=5 alive, in native, blocked,
> daemon
>    -- Blocked trying to get lock:
> org/drools/event/RuleBaseEventSupport at 0x2aab52d6f518[fat lock]
>    at jrockit/vm/Threads.waitForUnblockSignal()V(Native Method)
>    at jrockit/vm/Locks.fatLockBlockOrSpin(Locks.java:1679)[optimized]
>    at jrockit/vm/Locks.lockFat(Locks.java:1780)[optimized]
>    at
> jrockit/vm/Locks.monitorEnterSecondStageHard(Locks.java:1312)[optimized]
>    at jrockit/vm/Locks.monitorEnterSecondStage(Locks.java:1259)[optimized]
>    at
> org/drools/event/AbstractEventSupport.addEventListener(AbstractEventSupport.java:65)[inlined]
>    at
> org/drools/common/AbstractRuleBase.addEventListener(AbstractRuleBase.java:1018)[optimized]
>    at
> org/drools/impl/KnowledgeBaseImpl.addEventListener(KnowledgeBaseImpl.java:127)[optimized]
>    at
> org/jbpm/process/instance/ProcessRuntimeImpl.initProcessEventListeners(ProcessRuntimeImpl.java:201)
>    at
> org/jbpm/process/instance/ProcessRuntimeImpl.<init>(ProcessRuntimeImpl.java:68)[optimized]
>    at
> org/jbpm/process/instance/ProcessRuntimeFactoryServiceImpl.newProcessRuntime(ProcessRuntimeFactoryServiceImpl.java:10)
>    at
> org/jbpm/process/instance/ProcessRuntimeFactoryServiceImpl.newProcessRuntime(ProcessRuntimeFactoryServiceImpl.java:6)
>    at
> org/drools/runtime/process/ProcessRuntimeFactory.newProcessRuntime(ProcessRuntimeFactory.java:12)
>    at
> org/drools/common/AbstractWorkingMemory.createProcessRuntime(AbstractWorkingMemory.java:359)[inlined]
>    at
> org/drools/common/AbstractWorkingMemory.setKnowledgeRuntime(AbstractWorkingMemory.java:1260)[inlined]
>    at
> org/drools/impl/StatefulKnowledgeSessionImpl.<init>(StatefulKnowledgeSessionImpl.java:116)[inlined]
>    at
> org/drools/impl/StatelessKnowledgeSessionImpl.newWorkingMemory(StatelessKnowledgeSessionImpl.java:129)[inlined]
>    at
> org/drools/impl/StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:293)[optimized]
>    at
> br/com/cielo/engineRules/services/impl/CancelamentoRuleBean.validarRegrasCancelamento(CancelamentoRuleBean.java:79)[optimized]
>    at
> br/com/cielo/engineRules/services/impl/CancelamentoRuleEJB_vyscvn_EOImpl.validarRegrasCancelamento(CancelamentoRuleEJB_vyscvn_EOImpl.java:205)[optimized]
>    at
> br/com/cielo/engineRules/services/impl/CancelamentoRuleEJB_vyscvn_EOImpl_WLSkel.invoke(ILweblogic/rmi/spi/InboundRequest;Lweblogic/rmi/spi/OutboundResponse;Ljava/lang/Object;)Lweblogic/rmi/spi/OutboundResponse;(Unknown
> Source)[optimized]
>    at
> weblogic/rmi/internal/BasicServerRef.invoke(BasicServerRef.java:589)[optimized]
>    at
> weblogic/rmi/cluster/ClusterableServerRef.invoke(ClusterableServerRef.java:230)[optimized]
>    at
> weblogic/rmi/internal/BasicServerRef$1.run(BasicServerRef.java:477)[inlined]
>    at
> weblogic/security/acl/internal/AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)[inlined]
>    at
> weblogic/security/service/SecurityManager.runAs(Lweblogic/security/acl/internal/AuthenticatedSubject;Lweblogic/security/acl/internal/AuthenticatedSubject;Ljava/security/PrivilegedExceptionAction;)Ljava/lang/Object;(Unknown
> Source)[inlined]
>    at
> weblogic/rmi/internal/BasicServerRef.handleRequest(BasicServerRef.java:473)[inlined]
>    at
> weblogic/rmi/internal/wls/WLSExecuteRequest.run(WLSExecuteRequest.java:118)[optimized]
>    at
> weblogic/work/ExecuteThread.execute(ExecuteThread.java:201)[optimized]
>    at weblogic/work/ExecuteThread.run(ExecuteThread.java:173)
>    at jrockit/vm/RNI.c2java(JJJJJ)V(Native Method)
>    -- end of trace
> 
> I went to Drool's source code and there's a synchronized section right
> before the lock. I'm afraid Drools doesn't support multi-thread processing.
> 
> Does anyone know anything about this issue???
> 
> Tks
> 
> 
> 
> 
> --
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