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  1. Drools
  2. DROOLS-6432

Calling fireAllRules simultaneously from multiple threads sometimes causes an exception inside MVELConsequence#evaluate.

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    • Icon: Bug Bug
    • Resolution: Done
    • Icon: Major Major
    • None
    • 7.44.0.Final, 7.55.0.Final
    • core engine
    • 2021 Week 25-27 (from Jun 21)
    • Hide
      1. Extract reproducer. 
        $ unzip reproducer_mt_2a.zip
$ cd reproducer_mt_2a
      2. Build and execute the rule on a machine with many cpu/cores. 
        $ ./run_mvn

        run_mvn script builds with -DgenerateModel=NO and then runs the test (*2) 100 times. The output is written to reproducer_mt_2a_output_YYYYMMDDhhmmss.log.txt. You might be able to see exceptions like (*e1) or (*e2) several times of 100 times.

      Show
      Extract reproducer. $ unzip reproducer_mt_2a.zip $ cd reproducer_mt_2a Build and execute the rule on a machine with many cpu/cores. $ ./run_mvn run_mvn script builds with -DgenerateModel=NO and then runs the test (*2) 100 times. The output is written to reproducer_mt_2a_output_ YYYYMMDDhhmmss .log.txt . You might be able to see exceptions like (*e1) or (*e2) several times of 100 times.
    • Undefined
    • NEW
    • NEW

      When we build a rule written in MVEL dialect like (*1) with executable model disabled and run the rule using the test code like (*2), MVEL syntax error like (*e1) or (*e2) sometimes occurs though the rule normally does not cause errors. The test code simultaneously executes multiple jobs each of which creates a new KieSession, inserts objects and calls fireAllRules.

      This issue is similar to RHDM-1629. However, from the stack trace of the exception (*e1) and (*e2), it is different in the way that it does not occur inside MvelConstraint#evaluate but occurs inside MVELConsequence#evaluate (*e1-1) and (*e2-1).

      (*1)

      package com.example.reproducer

dialect "mvel"

rule "rule_mt_2a"
    when
        $bus : Bus( $title : "POWER PLANT" )
    then
        System.out.println("***** Action of rule_mt_2a");
        System.out.println("***** artist: " + $bus.karaoke.dvd[$title].artist);
end

      (*2) Test code (In the actual code in the reproducer, java.util.concurrent.Semaphore is used for making reproducibility higher.)

          KieServices kServices = KieServices.Factory.get();
    KieContainer kContainer = kServices.getKieClasspathContainer();

    int THREADS = 32;
    int REQUESTS = 10000;

    ExecutorService pool = Executors.newFixedThreadPool(THREADS);
    List<Future<?>> fs = new ArrayList<>();

    System.out.println("***** start threads");
    for (int i = 0; i < REQUESTS; i++) {
        fs.add(pool.submit(new Runnable() {
            public void run() {
                KieSession kSession = kContainer.newKieSession("session1");

                Bus bus1 = new Bus("red", 30);
                bus1.getKaraoke().getDvd().put("POWER PLANT", new Album("POWER PLANT", "GAMMA RAY"));
                bus1.getKaraoke().getDvd().put("Somewhere Out In Space", new Album("Somewhere Out In Space", "GAMMA RAY"));
                kSession.insert(bus1);

                try {
                    kSession.fireAllRules();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                
                kSession.dispose();
                kSession.destroy();
            }
        }));
    }

      (*e1)

      Exception executing consequence for rule "rule_mt_2a" in com.example.reproducer: [Error: unable to resolve method using strict-mode: java.lang.Object.artist()]
[Near : {... .out.println("***** artist: " + $bus.karaoke.dvd[$ ....}]
                                 ^
[Line: 2, Column: 35]
        at org.drools.core.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
        at org.drools.core.common.DefaultAgenda.handleException(DefaultAgenda.java:1306)
        at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:455)
        at org.drools.core.phreak.RuleExecutor.fireActivation(RuleExecutor.java:395)
        at org.drools.core.phreak.RuleExecutor.fire(RuleExecutor.java:151)
        at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:103)
        at org.drools.core.concurrent.AbstractRuleEvaluator.internalEvaluateAndFire(AbstractRuleEvaluator.java:33)
        at org.drools.core.concurrent.SequentialRuleEvaluator.evaluateAndFire(SequentialRuleEvaluator.java:43)
        at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1116)
        at org.drools.core.common.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:1063)
        at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1055)
        at org.drools.core.impl.StatefulKnowledgeSessionImpl.internalFireAllRules(StatefulKnowledgeSessionImpl.java:1346)
        at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1337)
        at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1321)
        at com.example.reproducer.DroolsTest$1.run(DroolsTest.java:73)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: [Error: unable to resolve method using strict-mode: java.lang.Object.artist()]
[Near : {... .out.println("***** artist: " + $bus.karaoke.dvd[$ ....}]
                                 ^
[Line: 2, Column: 35]
        at org.mvel2.compiler.PropertyVerifier.getMethod(PropertyVerifier.java:581)
        at org.mvel2.compiler.PropertyVerifier.getBeanProperty(PropertyVerifier.java:295)
        at org.mvel2.compiler.PropertyVerifier.analyze(PropertyVerifier.java:133)
        at org.mvel2.compiler.ExpressionCompiler.verify(ExpressionCompiler.java:400)
        at org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:259)
        at org.mvel2.util.ParseTools.subCompileExpression(ParseTools.java:2118)
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:969)
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:400)
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:167)
        at org.mvel2.ast.ASTNode.optimize(ASTNode.java:159)
        at org.mvel2.ast.ASTNode.getReducedValueAccelerated(ASTNode.java:115)
        at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)
        at org.mvel2.compiler.CompiledExpression.getDirectValue(CompiledExpression.java:123)
        at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:119)
        at org.mvel2.MVEL.executeExpression(MVEL.java:945)
        at org.drools.mvel.expr.MVELConsequence.evaluate(MVELConsequence.java:108)    .......... (*e1-1)
        at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:448)
        ... 17 more

      (*e2)

      Exception executing consequence for rule "rule_mt_2a" in com.example.reproducer: [Error: not a statement, or badly formed structure]
[Near : {... ("***** artist: " + $bus.karaoke.dvd[$title].artis ....}]
                                 ^
[Line: 2, Column: 47]
        at org.drools.core.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
        at org.drools.core.common.DefaultAgenda.handleException(DefaultAgenda.java:1306)
        at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:455)
        at org.drools.core.phreak.RuleExecutor.fireActivation(RuleExecutor.java:395)
        at org.drools.core.phreak.RuleExecutor.fire(RuleExecutor.java:151)
        at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:103)
        at org.drools.core.concurrent.AbstractRuleEvaluator.internalEvaluateAndFire(AbstractRuleEvaluator.java:33)
        at org.drools.core.concurrent.SequentialRuleEvaluator.evaluateAndFire(SequentialRuleEvaluator.java:43)
        at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1116)
        at org.drools.core.common.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:1063)
        at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1055)
        at org.drools.core.impl.StatefulKnowledgeSessionImpl.internalFireAllRules(StatefulKnowledgeSessionImpl.java:1346)
        at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1337)
        at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1321)
        at com.example.reproducer.DroolsTest$1.run(DroolsTest.java:73)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: [Error: not a statement, or badly formed structure]
[Near : {... ("***** artist: " + $bus.karaoke.dvd[$title].artis ....}]
                                 ^
[Line: 2, Column: 47]
        at org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:312)
        at org.mvel2.util.ParseTools.subCompileExpression(ParseTools.java:2118)
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:969)
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:400)
        at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:167)
        at org.mvel2.ast.ASTNode.optimize(ASTNode.java:159)
        at org.mvel2.ast.ASTNode.getReducedValueAccelerated(ASTNode.java:115)
        at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)
        at org.mvel2.compiler.CompiledExpression.getDirectValue(CompiledExpression.java:123)
        at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:119)
        at org.mvel2.MVEL.executeExpression(MVEL.java:945)
        at org.drools.mvel.expr.MVELConsequence.evaluate(MVELConsequence.java:108)    .......... (*e2-1)
        at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:448)
        ... 17 more
Caused by: java.lang.NullPointerException
        at org.mvel2.compiler.PropertyVerifier.getCollectionProperty(PropertyVerifier.java:403)
        at org.mvel2.compiler.PropertyVerifier.analyze(PropertyVerifier.java:139)
        at org.mvel2.compiler.ExpressionCompiler.verify(ExpressionCompiler.java:400)
        at org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:259)
        ... 29 more

        1. reproducer_mt_2a.zip
          11 kB

              mfusco@redhat.com Mario Fusco
              rhn-support-tkobayas Toshiya Kobayashi
              Daniel Rosa Daniel Rosa
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                Created:
                Updated:
                Resolved: