[jboss-jira] [JBoss JIRA] Commented: (JBRULES-2865) Drools Flow execution with single RuleSet node (besides Start and Stop nodes) results with no ruleset rules execution and java.lang.OutOfMemoryError.

[Kris Verlaenen (JIRA)]

    [ https://issues.jboss.org/browse/JBRULES-2865?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12598006#comment-12598006 ] 

Kris Verlaenen commented on JBRULES-2865:
-----------------------------------------

Thanks a lot for the example project.  There indeed was a difference between the valid and invalid example in Drools 5.1.1 (which no longer exists in the latest Drools 5.2 SNAPSHOT code).   The reason that your rules are not executed (and this is actually the expected behavior) is that rules are not executed by default, only when you call fireAllRules().  So that means, if a ruleset node is reached, the process will wait until those rules are executed.  If not fireAllRules() is called, this means no rules will be executed and the process instance will simply wait.

To get the rules to fire (and the process instance to continue), simply call ksession.fireAllRules() to execute the rules after call startProcess().

The reason that there was a difference between both version is that in Drools 5.1, fireAllRules() was called automatically after completing a work item (like the log element in this case).  If you want to avoid having to call fireAllRules() manually, you can also run the engine in reactive mode, meaning it will automatically execute rules when they are activated.

> Drools Flow execution with single RuleSet node (besides Start and Stop nodes) results with no ruleset rules execution and java.lang.OutOfMemoryError.
> -----------------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: JBRULES-2865
>                 URL: https://issues.jboss.org/browse/JBRULES-2865
>             Project: Drools
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: drools-core (flow)
>    Affects Versions: 5.1.0.FINAL, 5.1.1.FINAL
>         Environment: all
>            Reporter: Marek B
>            Assignee: Kris Verlaenen
>         Attachments: jbrules_2865.zip
>
>
> Trying to invoke drools flow with single RuleSet element only (besides Start/Stop elems) results in java.lang.OutOfMemoryError: GC overhead limit exceeded.
> Also this bug affects probably all flows, with RuleSet element as first in execution flow.
> See stacktrace
>  Exception in thread "Worker#xxx.xxxxxx.xxx(3)" java.lang.OutOfMemoryError: GC overhead limit exceeded
>         at java.util.Arrays.copyOf(Arrays.java:2746)
>         at java.util.concurrent.CopyOnWriteArrayList.add(CopyOnWriteArrayList.java:420)
>         at org.drools.process.instance.event.DefaultSignalManager.addEventListener(DefaultSignalManager.java:57)
>         at org.drools.workflow.instance.impl.WorkflowProcessInstanceImpl.addEventListener(WorkflowProcessInstanceImpl.java:377)
>         at org.drools.workflow.instance.node.RuleSetNodeInstance.addRuleSetListener(RuleSetNodeInstance.java:55)
>         at org.drools.workflow.instance.node.RuleSetNodeInstance.internalTrigger(RuleSetNodeInstance.java:41)
>         at org.drools.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:117)
>         at org.drools.workflow.instance.impl.NodeInstanceImpl.triggerConnection(NodeInstanceImpl.java:178)
>         at org.drools.workflow.instance.impl.NodeInstanceImpl.triggerCompleted(NodeInstanceImpl.java:144)
>         at org.drools.workflow.instance.node.StartNodeInstance.triggerCompleted(StartNodeInstance.java:49)
>         at org.drools.workflow.instance.node.StartNodeInstance.internalTrigger(StartNodeInstance.java:41)
>         at org.drools.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:117)
>         at org.drools.ruleflow.instance.RuleFlowProcessInstance.internalStart(RuleFlowProcessInstance.java:32)
>         at org.drools.process.instance.impl.ProcessInstanceImpl.start(ProcessInstanceImpl.java:192)
>         at org.drools.workflow.instance.impl.WorkflowProcessInstanceImpl.start(WorkflowProcessInstanceImpl.java:309)
>         at org.drools.common.AbstractWorkingMemory.startProcess(AbstractWorkingMemory.java:1644)
>         at org.drools.impl.StatefulKnowledgeSessionImpl.startProcess(StatefulKnowledgeSessionImpl.java:306)

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