[rules-dev] memory issue (memory leak?) on trunk (probably due true modify changes)

Sat Mar 13 18:54:40 EST 2010

Interesting error.

One explanation of it: http://stackoverflow.com/questions/1393486/what-means-the-error-message-java-lang-outofmemoryerror-gc-overhead-limit-excee

Sent from my phone.

On 13/03/2010, at 8:21 PM, Geoffrey De Smet <ge0ffrey.spam at gmail.com>  
wrote:

> Hi guys,
>
> With great improvements usually come instability for a while :)
> Trunk has memory issue, probably a memory leak of a small object.
>
> I've run ExmaminationBenchmarkApp with the program arg "short" 3 times
> with the exact same configuration (it is a 100% reproducible run):
>
> 1) Before the true modify changes with 512m max memory
> Succeeds (100 steps but even 10000 steps work) with no slow down.
>
> 2) After true modify changes with 512m max memory
> Fails after 27 steps, starts slowing down at 24 steps.
>
> 3) After true modify changes with 1024m max memory
> Fails after 57 steps, starts slowing down at 54 steps.
>
> Both 2) and 3) fail with the exception:
> Exception in thread "main" java.lang.OutOfMemoryError: GC overhead  
> limit
> exceeded
>
> So it's not a heap space error or a perm space error, but a GC  
> overhead
> limit instead. Literally this means it's doing more GC then running,
> but 99% of the time this means that the heap is so full that the GC  
> has
> little or no free space to work with.
> This kind of memory leak happens when the iteration make 101 objects  
> but
> only removes 100 objects and the iteration is run a lot (like 10000+  
> times).
> You don't get a heap space error, because before that happens,
> there is point where you have a garbaged collected free memory for 10
> objects and a ungarbaged collected free memory for 100 objects. At  
> that
> point the GC is running over 98% of the time, which is a VM treshold  
> and
> the error is thrown,
> even though 10 iterations later you would get a heap space error.
>
>
> Logs:
>
> 1)
> TODO
>
> 2)
> 2010-03-13 09:28:36,973 [main] INFO  Step index (21), time spend  
> (37245)
> taking step (323 {D180|S9} @ 9 {D210} + 5 {C65} => 52 {D210}) out of
> 1402 accepted moves.
> 2010-03-13 09:28:38,454 [main] INFO  Step index (22), time spend  
> (38727)
> taking step (367 {D190|S40} @ 28 {D210} + 5 {C65} => 19 {D210}) out of
> 1366 accepted moves.
> 2010-03-13 09:28:39,903 [main] INFO  Step index (23), time spend  
> (40176)
> taking step (230 {D120|S15} @ 7 {D210} + 3 {C60} => 12 {D210}) out of
> 1366 accepted moves.
> 2010-03-13 09:28:43,901 [main] INFO  Step index (24), time spend  
> (44174)
> taking step (190 {D90|S6} @ 1 {D210} + 3 {C60} <=> 205 {D120|S6} @ 8
> {D210} + 6 {C111}) out of 1392 accepted moves.
> 2010-03-13 09:28:50,631 [main] INFO  Step index (25), time spend  
> (50904)
> taking step (420 {D180|S6} @ 46 {D210} + 2 {C129} => 25 {D210}) out of
> 1396 accepted moves.
> 2010-03-13 09:29:06,184 [main] INFO  Step index (26), time spend  
> (66457)
> taking step (211 {D180|S53} @ 15 {D210} + 0 {C260} => 23 {D210}) out  
> of
> 1383 accepted moves.
> 2010-03-13 09:29:46,589 [main] INFO  Step index (27), time spend
> (106862) taking step (39 {D120|S15} @ 50 {D210} + 2 {C129} => 43  
> {D210})
> out of 1383 accepted moves.
> Exception in thread "main" java.lang.OutOfMemoryError: GC overhead  
> limit
> exceeded
>    at java.util.HashMap.addEntry(HashMap.java:753)
>    at java.util.HashMap.put(HashMap.java:385)
>    at java.util.HashMap.putAll(HashMap.java:524)
>    at
> org.drools.rule.GroupElement$Type.getOuterDeclarations 
> (GroupElement.java:406)
>    at org.drools.rule.GroupElement.getOuterDeclarations 
> (GroupElement.java:109)
>    at
> org.drools.base.DefaultKnowledgeHelper.getDeclaration 
> (DefaultKnowledgeHelper.java:213)
>    at
> org.drools.planner.examples.examination.solver.Rule_periodSpread_0DefaultConsequenceInvoker.evaluate( 
> Rule_periodSpread_0DefaultConsequenceInvoker.java:21)
>    at org.drools.common.DefaultAgenda.fireActivation 
> (DefaultAgenda.java:903)
>    at org.drools.common.DefaultAgenda.fireNextItem 
> (DefaultAgenda.java:850)
>    at org.drools.common.DefaultAgenda.fireAllRules 
> (DefaultAgenda.java:1061)
>    at
> org.drools.common.AbstractWorkingMemory.fireAllRules 
> (AbstractWorkingMemory.java:741)
>    at
> org.drools.common.AbstractWorkingMemory.fireAllRules 
> (AbstractWorkingMemory.java:707)
> ...
>
> 3)
> 2010-03-13 09:47:38,303 [main] INFO  Step index (55), time spend
> (114213) taking step (186 {D90|S17} @ 24 {D210} + 5 {C65} <=> 516
> {D180|S12} @ 15 {D210} + 0 {C260}) out of 1382 accepted moves.
> 2010-03-13 09:48:02,062 [main] INFO  Step index (56), time spend
> (137972) taking step (498 {D120|S17} @ 28 {D210} + 0 {C260} => 1  
> {C100})
> out of 1389 accepted moves.
> 2010-03-13 09:48:35,748 [main] INFO  Step index (57), time spend
> (171658) taking step (15 {D135|S96} @ 16 {D210} + 1 {C100} <=> 164
> {D180|S48} @ 3 {D210} + 0 {C260}) out of 1378 accepted moves.
> Exception in thread "main" java.lang.OutOfMemoryError: GC overhead  
> limit
> exceeded
>    at java.lang.Integer.valueOf(Integer.java:625)
>    at
> org.drools.common.TruthMaintenanceSystem.removeLogicalDependencies 
> (TruthMaintenanceSystem.java:180)
>    at
> org.drools.common.AbstractWorkingMemory.removeLogicalDependencies 
> (AbstractWorkingMemory.java:1455)
>    at
> org.drools.reteoo.RuleTerminalNode.retractLeftTuple 
> (RuleTerminalNode.java:266)
>    at
> org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateRetractLeftTuple( 
> SingleLeftTupleSinkAdapter.java:176)
>    at
> org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateRetractLeftTuple( 
> SingleLeftTupleSinkAdapter.java:57)
>    at
> org.drools.reteoo.EvalConditionNode.modifyLeftTuple 
> (EvalConditionNode.java:250)
>    at
> org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateModifyChildLeftTuple( 
> SingleLeftTupleSinkAdapter.java:198)
>    at org.drools.reteoo.JoinNode.modifyLeftTuple(JoinNode.java:304)
>    at
> org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateModifyChildLeftTuple( 
> SingleLeftTupleSinkAdapter.java:209)
>    at org.drools.reteoo.JoinNode.modifyRightTuple(JoinNode.java:221)
>    at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:317)
>    at
> org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject 
> (CompositeObjectSinkAdapter.java:444)
>    at
> org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject 
> (CompositeObjectSinkAdapter.java:412)
>    at org.drools.reteoo.ObjectTypeNode.modifyObject 
> (ObjectTypeNode.java:262)
>    at org.drools.reteoo.EntryPointNode.modifyObject 
> (EntryPointNode.java:174)
>    at
> org.drools.common.AbstractWorkingMemory.update 
> (AbstractWorkingMemory.java:1392)
>    at
> org.drools.common.AbstractWorkingMemory.update 
> (AbstractWorkingMemory.java:1288)
>
>
> -- 
> With kind regards,
> Geoffrey De Smet
>
> _______________________________________________
> rules-dev mailing list
> rules-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-dev