Drools lock in StatelessKnowledgeSessionImpl. --------------------------------------------- Key: DROOLS-458 URL: https://issues.jboss.org/browse/DROOLS-458 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Affects Versions: 6.0.1.Final Environment: Tomcat 7 Reporter: Desmond Silveira Assignee: Mario Fusco Attachments: la3ldspg05b.txt 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: {noformat} "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) {noformat} Here is the code that I use to call Drools: {code:java} 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; } } {code}