10:28 a.m.
I am using Drools 5.1.1 to design our rule engine, the rule engine need to
dynamic loading of rules from Guvnor because our marking team need to change
the rules frequently(about 40~100 times every day), we have over 5000 rules
in Guvnor.
This is my code ahout that:
public KnowledgeBase getKnowledgeBase() {
// hold a static reference in class
if(kagent != null) {
return kagent.getKnowledgeBase();
}
ResourceChangeScannerConfiguration sconf =
ResourceFactory.getResourceChangeScannerService().newResourceChangeScannerConfiguration();
sconf.setProperty("drools.resource.scanner.interval", "5");
ResourceFactory.getResourceChangeScannerService().configure(sconf);
ResourceFactory.getResourceChangeScannerService().start();
ResourceFactory.getResourceChangeNotifierService().start();
kagent = KnowledgeAgentFactory.newKnowledgeAgent("myagent");
kagent.applyChangeSet(ResourceFactory.newClassPathResource("changeset-url.xml"));
return kagent.getKnowledgeBase();
}
This is content of changeset-url.xml:
<change-set xmlns='http://drools.org/drools-5.0/change-set'
xmlns:xs='http://www.w3.org/2001/XMLSchema-instance'
xs:schemaLocation='http://drools.org/drools-5.0/change-set
http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-api/src/...
<add
<resource
source='http://localhost:8080/drools-guvnor/org.drools.guvnor.Guvnor/package/PackageName/snapshot_release'
type='PKG' / </add </change-set
After i start my service, i found each time When i rebuild package and
created new snapshot to snapshot_release, my service indeed can find the
changing and start to reload rules from guvnor, but memory increased about
50M, it didn't down even if the reloading had finished. After i reput do
this step many times(about 25 times), OutOfMemoryError happened.
So, I want to know, why memory increased continually？It sames drools didn't
do garbage collection.
Has anyone experienced this?
Thanks
- Oliver
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6:44 p.m.
Any idea is appreciated, it's critical for my project. Thanks.
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9:26 p.m.
Try using JMAP to get a heap dump, and then find an analysis tool you like to find the
memory leak. It is probably due to a memory leak in MVEL that show itself when you do
dynamic rules allocation (I don't think it has been fixed yet), but I can't be
sure unless you find the class that is leaking.
Jason Smith
________________________________________
From: rules-users-bounces(a)lists.jboss.org [rules-users-bounces(a)lists.jboss.org] On Behalf
Of Oliver Liu [liuyy2000(a)hotmail.com]
Sent: Monday, June 20, 2011 5:44 PM
To: rules-users(a)lists.jboss.org
Subject: Re: [rules-users] OutOfMemoryError happens when dynamic loading of Rules from
Guvnor frequently
Any idea is appreciated, it's critical for my project. Thanks.
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8:41 p.m.
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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Oliver Liu