[jboss-jira] [JBoss JIRA] (DROOLS-309) Multiple threads working with traits against same knowledge base hangs

[Mario Fusco (JIRA)]

     [ https://issues.jboss.org/browse/DROOLS-309?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Mario Fusco resolved DROOLS-309.
--------------------------------

    Fix Version/s: 5.5.1.Final
                   6.0.0.Final
       Resolution: Done

    
> Multiple threads working with traits against same knowledge base hangs
> ----------------------------------------------------------------------
>
>                 Key: DROOLS-309
>                 URL: https://issues.jboss.org/browse/DROOLS-309
>             Project: Drools
>          Issue Type: Quality Risk
>      Security Level: Public(Everyone can see) 
>    Affects Versions: 5.5.0.Final
>            Reporter: James Myers
>            Assignee: Mario Fusco
>             Fix For: 5.5.1.Final, 6.0.0.Final
>
>
> In our web system, we are creating new StatefulKnowledgeSession per user session and executing a set of rules containing trait donning.  This starts to hang (seemingly indefinitely) with following type of stack trace (usually initiated from insert/update):
> {quote}
>    java.lang.Thread.State: RUNNABLE
> 	at org.drools.core.util.TripleStore.getAll(TripleStore.java:188)
> 	at org.drools.factmodel.traits.TripleBasedStruct.getTriplesForSubject(TripleBasedStruct.java:165)
> 	at org.drools.factmodel.traits.ThingorgdroolsfactmodeltraitsTraitSession$ItemWrapperProxyWrapper.hashCode(Unknown Source)
> 	at org.drools.factmodel.traits.TraitProxy.hashCode(TraitProxy.java:110)
> 	at org.drools.factmodel.traits.ThingorgdroolsfactmodeltraitsTraitSession$ItemWrapperProxy.hashCode(Unknown Source)
> 	at org.drools.common.DefaultFactHandle.<init>(DefaultFactHandle.java:110)
> 	at org.drools.common.DefaultFactHandle.<init>(DefaultFactHandle.java:98)
> 	at org.drools.common.TraitFactHandle.<init>(TraitFactHandle.java:26)
> 	at org.drools.reteoo.ReteooFactHandleFactory.newFactHandle(ReteooFactHandleFactory.java:80)
> 	at org.drools.common.AbstractFactHandleFactory.newFactHandle(AbstractFactHandleFactory.java:68)
> 	at org.drools.common.AbstractFactHandleFactory.newFactHandle(AbstractFactHandleFactory.java:53)
> 	at org.drools.common.NamedEntryPoint.createHandle(NamedEntryPoint.java:765)
> 	at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:301)
> 	at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:903)
> {quote}
> Here is a unit test for org.drools.factmodel.traits.TraitTest.  It's not perfect because it will spawn thread that might never die and may need thread/iteration count increased to fail consistently, but capturing a stack trace a few seconds in should show all threads in "getAll()":
> {code}
>     @Traitable
>     public static class Item {
>     	private String id;
>     	public String getId() {
>     		return id;
>     	}
>     	public void setId(String id) {
>     		this.id = id;
>     	}
>     }
>     public static class TraitRulesThread implements Runnable {
>     	int threadIndex;
>     	int numRepetitions;
>     	StatefulKnowledgeSession ksession;
>     	public TraitRulesThread(int threadIndex, int numRepetitions, final StatefulKnowledgeSession ksession) {
>     		this.threadIndex = threadIndex;
>     		this.numRepetitions = numRepetitions;
>     		this.ksession = ksession;
>     	}
>     	public void run() {
>     		for (int repetitionIndex = 0; repetitionIndex < numRepetitions; repetitionIndex++) {
>     			final Item i = new Item();
>     			i.setId(String.format("testId_%d%d", threadIndex, repetitionIndex));
>     			ksession.insert(i);
>     			ksession.fireAllRules();
>     		}
>     	}
>     }
>     @Test
>     public void testMultithreadingTraits() throws InterruptedException {
>     	final String s1 = "package test;\n" +
>     	"import org.drools.factmodel.traits.TraitTest.Item;\n" +
>     	"declare Item end\n" +
>     	"declare trait ItemStyle\n" +
>     	"	id: String\n" +
>     	"	adjustable: boolean\n" +
>     	"end\n" +
>     	"rule \"Don ItemStyle\"\n" +
>     	"	no-loop true\n" +
>     	"	when\n" +
>     	"		$p : Item ()\n" +
>     	"		not ItemStyle ( id == $p.id )\n" +
>     	"	then\n" +
>     	"		don($p, ItemStyle.class);\n" +
>     	"end\n" +
>     	"rule \"Item Style - Adjustable\"" +
>     	"	no-loop true" +
>     	"	when" +
>     	"		$style : ItemStyle ( !adjustable )" +
>     	"		Item (" +
>     	"			id == $style.id " +
>     	"		)" +
>     	"	then" +
>     	"		modify($style) {" +
>     	"			setAdjustable(true)" +
>     	"		};" +
>     	"end";
>     	final KnowledgeBase kbase = getKnowledgeBaseFromString(s1);
>     	// might need to tweak these numbers.  often works with 7-10,100,60, but often fails 15-20,100,60
>     	int MAX_THREADS = 20;
>     	int MAX_REPETITIONS = 100;
>     	int MAX_WAIT_SECONDS = 60;
>     	final ExecutorService executorService = Executors.newFixedThreadPool(MAX_THREADS);
>     	for (int threadIndex = 0; threadIndex < MAX_THREADS; threadIndex++) {
>     		executorService.execute(new TraitRulesThread(threadIndex, MAX_REPETITIONS, kbase.newStatefulKnowledgeSession()));
>     	}
>     	executorService.shutdown();
>     	executorService.awaitTermination(MAX_WAIT_SECONDS, TimeUnit.SECONDS);
>     	final List<Runnable> queuedTasks = executorService.shutdownNow();
>     	assertEquals(0, queuedTasks.size());
>     	assertEquals(true, executorService.isTerminated());
>     }
> {code}

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