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  1. Drools
  2. DROOLS-458

Drools lock in StatelessKnowledgeSessionImpl.

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    • Icon: Bug Bug
    • Resolution: Won't Do
    • Icon: Major Major
    • None
    • 6.0.1.Final
    • None
    • None

    • Tomcat 7

      My Tomcat HTTP BIO connector threads (129 of them) got BLOCKED in my production Tomcat 7 instance because Drool 6.0.1 wasn't releasing a lock.

      Here is a snippet of the thread dump:

      "http-bio-172.16.216.19-80-exec-37513" - Thread t@6245360
   java.lang.Thread.State: BLOCKED
	at org.drools.core.runtime.process.ProcessRuntimeFactory.getProcessRuntimeFactoryService(ProcessRuntimeFactory.java:20)
	- waiting to lock <219dcd77> (a java.lang.Class) owned by "http-bio-172.16.216.19-80-exec-37511" t@6245358
	at org.drools.core.runtime.process.ProcessRuntimeFactory.newProcessRuntime(ProcessRuntimeFactory.java:12)
	at org.drools.core.common.AbstractWorkingMemory.createProcessRuntime(AbstractWorkingMemory.java:405)
	at org.drools.core.common.AbstractWorkingMemory.setKnowledgeRuntime(AbstractWorkingMemory.java:1770)
	at org.drools.core.impl.StatefulKnowledgeSessionImpl.<init>(StatefulKnowledgeSessionImpl.java:125)
	at org.drools.core.impl.StatelessKnowledgeSessionImpl.newWorkingMemory(StatelessKnowledgeSessionImpl.java:139)
	at org.drools.core.impl.StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:397)
	at com.local.lds.RuleEngineBean.applyKnowledge(RuleEngineBean.java:50)
	at com.local.lds.LdsBean.search(LdsBean.java:200)
	at com.local.lds.servlet.SearchServlet.doGet(SearchServlet.java:55)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
	- locked <3575a054> (a org.apache.tomcat.util.net.SocketWrapper)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
	- locked <719df963> (a java.util.concurrent.ThreadPoolExecutor$Worker)

"http-bio-172.16.216.19-80-exec-37511" - Thread t@6245358
   java.lang.Thread.State: RUNNABLE
	at org.kie.internal.utils.ServiceRegistryImpl.addDefault(ServiceRegistryImpl.java:212)
	- locked <3d710637> (a org.kie.internal.utils.ServiceRegistryImpl)
	at org.kie.internal.utils.ServiceRegistryImpl.addDefault(ServiceRegistryImpl.java:207)
	- locked <3d710637> (a org.kie.internal.utils.ServiceRegistryImpl)
	at org.drools.core.runtime.process.ProcessRuntimeFactory.loadProvider(ProcessRuntimeFactory.java:27)
	at org.drools.core.runtime.process.ProcessRuntimeFactory.getProcessRuntimeFactoryService(ProcessRuntimeFactory.java:21)
	- locked <219dcd77> (a java.lang.Class)
	at org.drools.core.runtime.process.ProcessRuntimeFactory.newProcessRuntime(ProcessRuntimeFactory.java:12)
	at org.drools.core.common.AbstractWorkingMemory.createProcessRuntime(AbstractWorkingMemory.java:405)
	at org.drools.core.common.AbstractWorkingMemory.setKnowledgeRuntime(AbstractWorkingMemory.java:1770)
	at org.drools.core.impl.StatefulKnowledgeSessionImpl.<init>(StatefulKnowledgeSessionImpl.java:125)
	at org.drools.core.impl.StatelessKnowledgeSessionImpl.newWorkingMemory(StatelessKnowledgeSessionImpl.java:139)
	at org.drools.core.impl.StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:397)
	at com.local.lds.RuleEngineBean.applyKnowledge(RuleEngineBean.java:50)
	at com.local.lds.LdsBean.search(LdsBean.java:200)
	at com.local.lds.servlet.SearchServlet.doGet(SearchServlet.java:55)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
	- locked <474f2464> (a org.apache.tomcat.util.net.SocketWrapper)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
	- locked <339f344e> (a java.util.concurrent.ThreadPoolExecutor$Worker)

"http-bio-172.16.216.19-80-exec-37447" - Thread t@6233953
   java.lang.Thread.State: BLOCKED
	at org.drools.core.common.ProjectClassLoader.loadClass(ProjectClassLoader.java:82)
	- waiting to lock <555896b3> (a org.drools.core.common.ProjectClassLoader) owned by "http-bio-172.16.216.19-80-exec-37519" t@6245366
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at org.drools.core.base.ClassFieldAccessorCache.getClass(ClassFieldAccessorCache.java:122)
	at org.drools.core.base.ClassFieldAccessorCache.getClassObjectType(ClassFieldAccessorCache.java:46)
	at org.drools.core.reteoo.ClassObjectTypeConf.<init>(ClassObjectTypeConf.java:89)
	at org.drools.core.common.ObjectTypeConfigurationRegistry.getObjectTypeConf(ObjectTypeConfigurationRegistry.java:71)
	at org.drools.core.common.AbstractWorkingMemory.initInitialFact(AbstractWorkingMemory.java:385)
	at org.drools.core.common.AbstractWorkingMemory.<init>(AbstractWorkingMemory.java:378)
	at org.drools.core.common.AbstractWorkingMemory.<init>(AbstractWorkingMemory.java:261)
	at org.drools.core.common.PhreakWorkingMemoryFactory.createWorkingMemory(PhreakWorkingMemoryFactory.java:15)
	at org.drools.core.impl.StatelessKnowledgeSessionImpl.newWorkingMemory(StatelessKnowledgeSessionImpl.java:134)
	at org.drools.core.impl.StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:397)
	at com.local.lds.RuleEngineBean.applyKnowledge(RuleEngineBean.java:50)
	at com.local.lds.LdsBean.search(LdsBean.java:200)
	at com.local.lds.servlet.SearchServlet.doGet(SearchServlet.java:55)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
	- locked <57e6b780> (a org.apache.tomcat.util.net.SocketWrapper)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
	- locked <726294fc> (a java.util.concurrent.ThreadPoolExecutor$Worker)

"http-bio-172.16.216.19-80-exec-37519" - Thread t@6245366
   java.lang.Thread.State: RUNNABLE
	at java.lang.ClassLoader.findLoadedClass0(Native Method)
	at java.lang.ClassLoader.findLoadedClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	- locked <555896b3> (a org.drools.core.common.ProjectClassLoader)
	at org.drools.core.common.ProjectClassLoader.internalLoadClass(ProjectClassLoader.java:99)
	at org.drools.core.common.ProjectClassLoader.loadClass(ProjectClassLoader.java:82)
	- locked <555896b3> (a org.drools.core.common.ProjectClassLoader)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at org.drools.core.base.ClassFieldAccessorCache.getClass(ClassFieldAccessorCache.java:122)
	at org.drools.core.base.ClassFieldAccessorCache.getClassObjectType(ClassFieldAccessorCache.java:46)
	at org.drools.core.reteoo.ClassObjectTypeConf.<init>(ClassObjectTypeConf.java:89)
	at org.drools.core.common.ObjectTypeConfigurationRegistry.getObjectTypeConf(ObjectTypeConfigurationRegistry.java:71)
	at org.drools.core.common.NamedEntryPoint.insert(NamedEntryPoint.java:164)
	at org.drools.core.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:1148)
	at org.drools.core.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:1092)
	at org.drools.core.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSessionImpl.java:308)
	at org.drools.core.impl.StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:400)
	at com.local.lds.RuleEngineBean.applyKnowledge(RuleEngineBean.java:50)
	at com.local.lds.LdsBean.search(LdsBean.java:200)
	at com.local.lds.servlet.SearchServlet.doGet(SearchServlet.java:55)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
	- locked <43c2901> (a org.apache.tomcat.util.net.SocketWrapper)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
	- locked <88f8fa9> (a java.util.concurrent.ThreadPoolExecutor$Worker)

      Here is the code that I use to call Drools:

          public static Collection<ResultSet> applyRule(String rule,
            KieBase kb, Collection<ResultSet> resultSets, SearchParameters params) {
        try {
            if (kb == null) {
                return resultSets;
            }
            StatelessKieSession ksession = kb.newStatelessKieSession();
            ksession.setGlobal(OUTPUT, new ArrayList<>());
            Collection<Object> collection = new ArrayList<Object>(resultSets);
            collection.add(params);
            ksession.execute(collection);
            return (Collection<ResultSet>) ksession.getGlobals().get(OUTPUT);
        } catch (ConsequenceException e) {
            LOG.error("Error in rule: " + rule + " " + e.getRule(), e);
            throw e;
        } catch (RuntimeException e) {
            LOG.error("Error in rule: " + rule, e);
            throw e;
        }
    }

        1. la3ldspg05b.txt
          892 kB
          Desmond Silveira

              mfusco@redhat.com Mario Fusco
              dhalsim2_jira Desmond Silveira (Inactive)
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                Created:
                Updated:
                Resolved: