[rules-users] OutOfMemoryError happens when dynamic loading of Rules from Guvnor frequently

[Oliver Liu]

I read the source code of org.drools.agent.impl.KnowledgeAgentImpl, in this
segment
private void rebuildResources(ChangeSetState changeSetState) {
...
        /*
         * Rebuild a new knowledge base. Try to use the old configuration if
         * possible
         */
        if (this.kbase != null) {
            this.kbase =
KnowledgeBaseFactory.newKnowledgeBase(((InternalRuleBase)
((KnowledgeBaseImpl) this.kbase).ruleBase).getConfiguration());
        } else {
            this.kbase = KnowledgeBaseFactory.newKnowledgeBase();
        }
...
}

Before giving a new value to  this.kbase, i think maybe we should release
resource in it, so i tried to change code like this:
[6/21/2011 12:34:16 PM] liuyy_skype:         if (this.kbase != null) {
            for(KnowledgePackage packs : this.kbase.getKnowledgePackages())
{             
             KnowledgePackageImp kpkg = ((KnowledgePackageImp)packs);
                for (Rule rule : kpkg.pkg.getRules()) {
                 removeKnowledgeDefinitionFromBase(rule);
                }
                for (Process process : kpkg.pkg.getRuleFlows().values()) {
                 removeKnowledgeDefinitionFromBase(process);
                }
                for (Function function : kpkg.pkg.getFunctions().values()) {
                 removeKnowledgeDefinitionFromBase(function);
                }
                for (TypeDeclaration dec :
kpkg.pkg.getTypeDeclarations().values()) { 
                 removeKnowledgeDefinitionFromBase(dec);
                }
       
                this.kbase.removeKnowledgePackage(kpkg.getName());
                kpkg.pkg.clear();       
                Runtime.getRuntime().gc();
            }

            this.kbase =
KnowledgeBaseFactory.newKnowledgeBase(((InternalRuleBase)
((KnowledgeBaseImpl) this.kbase).ruleBase).getConfiguration());
        } else {
            this.kbase = KnowledgeBaseFactory.newKnowledgeBase();
        }

Then i run my code, the memory indeed increased not so much like before, but
still rise. though the added code work, but i think there are some risk in
it, e.g. if the app are using a session which created from kbase, this code
may cause exception.

Any idea?

Thanks

Oliver

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