[rules-users] Drools compiler memory & stateless sessions?

[Kris Nuttycombe]

On Wed, Nov 26, 2008 at 1:10 PM, Edson Tirelli <tirelli at post.com> wrote:

>
>    Ok, lets start with a simple thing:
>
> 4128 instances <http://carrot.gaiam.com:7000/instances/0x2aaad6103ff0> of class
> org.drools.rule.Pattern<http://carrot.gaiam.com:7000/class/0x2aaad6103ff0>
>
>    I can't see how 16 rules can create that many patterns. Are you sure you
> are not recompiling/recreating your rulebase multiple times? If not, then we
> may have a serious problem...
>
>    []s
>    Edson



Thanks, Edson. I think that recompilation may be the problem; I'm creating
the RuleBase in a @PostConstruct method in an ejb3 stateless session bean,
and it looks like if multiple instances of the session bean are added to the
pool the rule base is compiled multiple times. So, how to get around this
problem? In another thread you said:

> Also, usage of statics is not always good, specially if you intent to run
your application in a JEE environment.

so I presume that using a regular old singleton to share the RuleBase
instance is not a good idea. Is there any approach you can suggest that will
avoid using statics? This app is running under Glassfish.

Thanks for your help,

Kris



>
>
> 2008/11/26 Kris Nuttycombe <kris.nuttycombe at gmail.com>
>
>> Hi, all,
>>
>> I'm encountering significant problems with running out of memory when
>> executing a small ruleset (only 16 rules, < 100 facts). I've run jmap on the
>> process (which has previously spawned multiple stateless sessions in
>> parallel) and it looks like Drools, and specifically the Eclipse jdt
>> compiler, is seriously eating up memory. The code calling the is fairly
>> simple; one of the initial facts is an accumulator that I refer to later:
>>
>>         StatelessSession session = ruleBase.newStatelessSession();
>>         session.execute(initialFact, accumulator);
>>
>>         accumulator.doSomething();
>>
>> where ruleBase is a shared instance, and initialFact is a base fact that
>> is expanded during rules processing. Is there something I should be doing to
>> dispose the session after use to release the objects created by the drools
>> compiler after use? I'm using a shared RuleBase, and I'm wondering whether
>> it is somehow keeping references around. Are these sorts of object counts to
>> be expected?
>>
>> Thanks,
>>
>> Kris
>> Instance Counts for All Classes (excluding platform) 104827 instances<http://carrot.gaiam.com:7000/instances/0x2aaacf5646f8>of class
>> net.jxta.impl.document.LiteXMLElement$charRange<http://carrot.gaiam.com:7000/class/0x2aaacf5646f8>
>> 26806 instances <http://carrot.gaiam.com:7000/instances/0x2aaacf5631e8>of class
>> net.jxta.impl.document.LiteXMLElement$tagRange<http://carrot.gaiam.com:7000/class/0x2aaacf5631e8>
>> 26733 instances <http://carrot.gaiam.com:7000/instances/0x2aaad66ea7f0>of class
>> org.eclipse.jdt.internal.compiler.lookup.MethodBinding<http://carrot.gaiam.com:7000/class/0x2aaad66ea7f0>
>> 17366 instances <http://carrot.gaiam.com:7000/instances/0x2aaad66e3c88>of class
>> [Lorg.eclipse.jdt.internal.compiler.lookup.TypeBinding;<http://carrot.gaiam.com:7000/class/0x2aaad66e3c88>
>> 12412 instances <http://carrot.gaiam.com:7000/instances/0x2aaacf032560>of class
>> com.sun.enterprise.loader.EJBClassLoader$SentinelInputStream<http://carrot.gaiam.com:7000/class/0x2aaacf032560>
>> 10974 instances <http://carrot.gaiam.com:7000/instances/0x2aaad5504450>of class
>> org.apache.commons.collections.SequencedHashMap$Entry<http://carrot.gaiam.com:7000/class/0x2aaad5504450>
>> 8683 instances <http://carrot.gaiam.com:7000/instances/0x2aaad68c3840> of
>> class org.eclipse.jdt.internal.compiler.codegen.CachedIndexEntry<http://carrot.gaiam.com:7000/class/0x2aaad68c3840>
>> 7708 instances <http://carrot.gaiam.com:7000/instances/0x2aaacf55e9d8> of
>> class net.jxta.impl.document.LiteXMLElement<http://carrot.gaiam.com:7000/class/0x2aaacf55e9d8>
>> 7450 instances <http://carrot.gaiam.com:7000/instances/0x2aaad5c4b6c0> of
>> class org.hibernate.engine.CollectionKey<http://carrot.gaiam.com:7000/class/0x2aaad5c4b6c0>
>> 6836 instances <http://carrot.gaiam.com:7000/instances/0x2aaaced3c3f8> of
>> class org.netbeans.modules.schema2beans.AttrProp<http://carrot.gaiam.com:7000/class/0x2aaaced3c3f8>
>> 6271 instances <http://carrot.gaiam.com:7000/instances/0x2aaad6642d18> of
>> class org.eclipse.jdt.internal.compiler.lookup.FieldBinding<http://carrot.gaiam.com:7000/class/0x2aaad6642d18>
>> 5643 instances <http://carrot.gaiam.com:7000/instances/0x2aaad6796890> of
>> class org.eclipse.jdt.internal.compiler.ast.MessageSend<http://carrot.gaiam.com:7000/class/0x2aaad6796890>
>> 4928 instances <http://carrot.gaiam.com:7000/instances/0x2aaad68a6018> of
>> class org.eclipse.jdt.internal.compiler.util.HashtableOfObject<http://carrot.gaiam.com:7000/class/0x2aaad68a6018>
>> 4895 instances <http://carrot.gaiam.com:7000/instances/0x2aaad66e3fa8> of
>> class [Lorg.eclipse.jdt.internal.compiler.lookup.ReferenceBinding;<http://carrot.gaiam.com:7000/class/0x2aaad66e3fa8>
>> 4546 instances <http://carrot.gaiam.com:7000/instances/0x2aaad669f968> of
>> class org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding<http://carrot.gaiam.com:7000/class/0x2aaad669f968>
>> 4472 instances <http://carrot.gaiam.com:7000/instances/0x2aaad687a0a8> of
>> class [Lorg.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding;<http://carrot.gaiam.com:7000/class/0x2aaad687a0a8>
>> 4128 instances <http://carrot.gaiam.com:7000/instances/0x2aaad6103ff0> of
>> class org.drools.rule.Pattern<http://carrot.gaiam.com:7000/class/0x2aaad6103ff0>
>> 3899 instances <http://carrot.gaiam.com:7000/instances/0x2aaacf493c90> of
>> class net.jxta.impl.id.UUID.UUID<http://carrot.gaiam.com:7000/class/0x2aaacf493c90>
>> 3867 instances <http://carrot.gaiam.com:7000/instances/0x2aaad5c416c0> of
>> class org.hibernate.engine.EntityEntry<http://carrot.gaiam.com:7000/class/0x2aaad5c416c0>
>> 3731 instances <http://carrot.gaiam.com:7000/instances/0x2aaad5c54d88> of
>> class org.hibernate.collection.PersistentSet<http://carrot.gaiam.com:7000/class/0x2aaad5c54d88>
>> 3685 instances <http://carrot.gaiam.com:7000/instances/0x2aaad66ca420> of
>> class org.eclipse.jdt.internal.compiler.lookup.UnresolvedReferenceBinding<http://carrot.gaiam.com:7000/class/0x2aaad66ca420>
>> 3360 instances <http://carrot.gaiam.com:7000/instances/0x2aaad6c12770> of
>> class org.drools.reteoo.SingleTupleSinkAdapter<http://carrot.gaiam.com:7000/class/0x2aaad6c12770>
>> 3266 instances <http://carrot.gaiam.com:7000/instances/0x2aaacf543dc0> of
>> class net.jxta.document.MimeMediaType<http://carrot.gaiam.com:7000/class/0x2aaacf543dc0>
>> 3264 instances <http://carrot.gaiam.com:7000/instances/0x2aaad6370288> of
>> class org.drools.spi.PatternExtractor<http://carrot.gaiam.com:7000/class/0x2aaad6370288>
>> 3163 instances <http://carrot.gaiam.com:7000/instances/0x2aaad5f8b990> of
>> class org.apache.axis.encoding.TypeMappingImpl$Pair<http://carrot.gaiam.com:7000/class/0x2aaad5f8b990>
>> 3137 instances <http://carrot.gaiam.com:7000/instances/0x2aaad5caad98> of
>> class org.hibernate.collection.PersistentBag<http://carrot.gaiam.com:7000/class/0x2aaad5caad98>
>> 2881 instances <http://carrot.gaiam.com:7000/instances/0x2aaad681b000> of
>> class org.eclipse.jdt.internal.compiler.lookup.MethodScope<http://carrot.gaiam.com:7000/class/0x2aaad681b000>
>> 2688 instances <http://carrot.gaiam.com:7000/instances/0x2aaad6161860> of
>> class org.drools.base.ClassFieldExtractor<http://carrot.gaiam.com:7000/class/0x2aaad6161860>
>>
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>>
>>
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