[jboss-jira] [JBoss JIRA] (DROOLS-1283) Memory leak using KieBuilder.build() method.

[Mario Fusco (JIRA)]

    [ https://issues.jboss.org/browse/DROOLS-1283?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13292862#comment-13292862 ] 

Mario Fusco commented on DROOLS-1283:
-------------------------------------

I reproduced the problem in a simpler way using the test case I'm pasting below. There isn't any assertion there but you can see the memory occupation constantly increasing at each loop.

{code}
    @Test
    public void testCreateKieBaseInLoop() {
        final String drl = "package " + this.getClass().getPackage().getName() + ";" +
                           " rule R1 \n" +
                           " when \n" +
                           "     String() \n" +
                           " then \n" +
                           " end ";

        final KieResources kieResources = KieServices.Factory.get().getResources();
        final org.kie.api.io.Resource drlResource = kieResources.newByteArrayResource( drl.getBytes(), "UTF-8" );
        drlResource.setTargetPath("src/main/resources/rule.drl");

        while (true) {
            createKieBase(drlResource);
            System.out.println(getUsedMemory());
        }
    }

    private void createKieBase(final org.kie.api.io.Resource... resources ) {
        final KieHelper kieHelper = new KieHelper();
        for ( org.kie.api.io.Resource resource : resources) {
            kieHelper.addResource(resource);
        }
        kieHelper.build();
    }

    private long getUsedMemory() {
        System.gc();
        final Runtime runtime = Runtime.getRuntime();
        return runtime.totalMemory() - runtime.freeMemory();
    }
{code}

The leak is not a real leak but only caused by the fact that all kcontainers are stored in this map https://github.com/droolsjbpm/drools/blob/master/drools-compiler/src/main/java/org/drools/compiler/kie/builder/impl/KieServicesImpl.java#L69

The kcontainers will be removed by that map when calling dispose() on the single kcontainer itself. The problem is that nobody is calling that dispose() method, even in our own KieHelper. Also we are not sure if we want to rely on the fact that the users will always call that dispose() method (that however is still not exposed in the public API) so we are still discussing all possible solutions.

> Memory leak using KieBuilder.build() method. 
> ---------------------------------------------
>
>                 Key: DROOLS-1283
>                 URL: https://issues.jboss.org/browse/DROOLS-1283
>             Project: Drools
>          Issue Type: Bug
>          Components: core engine
>    Affects Versions: 6.5.0.CR1
>            Reporter: Tibor Zimányi
>            Assignee: Mario Fusco
>              Labels: regression, reported-by-qe
>
> There is a memory leak when building KieBase using KieBuilder.build() method. When continuously calling kieBuilder.build() (also with no resources), the OOM exception occurs. 
> I will make PR with a reproducer for this. 



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