[infinispan-dev] ISPN-863 - Thoughts / Questions

[Dave]

All,

 

I am trying to test some changes that I made using Eclipse and the TestNG
plugin. I am not familiar with TestNG. Are there any settings that I should
make? Any ideas?

 

java.lang.OutOfMemoryError: Java heap space

      at
org.infinispan.util.concurrent.BoundedConcurrentHashMap$HashEntry.newArray(B
oundedConcurrentHashMap.java:295)

      at
org.infinispan.util.concurrent.BoundedConcurrentHashMap$Segment.<init>(Bound
edConcurrentHashMap.java:898)

      at
org.infinispan.util.concurrent.BoundedConcurrentHashMap.<init>(BoundedConcur
rentHashMap.java:1367)

      at
org.infinispan.container.DefaultDataContainer.<init>(DefaultDataContainer.ja
va:78)

      at
org.infinispan.container.DefaultDataContainer.<init>(DefaultDataContainer.ja
va:47)

      at
org.infinispan.container.DefaultDataContainer.unBoundedDataContainer(Default
DataContainer.java:93)

     at
org.infinispan.factories.DataContainerFactory.construct(DataContainerFactory
.java:53)

      at
org.infinispan.factories.AbstractComponentRegistry.getOrCreateComponent(Abst
ractComponentRegistry.java:315)

      at
org.infinispan.factories.AbstractComponentRegistry.invokeInjectionMethod(Abs
tractComponentRegistry.java:251)

      at
org.infinispan.factories.AbstractComponentRegistry$Component.injectDependenc
ies(AbstractComponentRegistry.java:840)

      at
org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
tComponentRegistry.java:225)

      at
org.infinispan.factories.ComponentRegistry.registerComponent(ComponentRegist
ry.java:120)

      at
org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
tComponentRegistry.java:192)

      at
org.infinispan.factories.AbstractComponentRegistry.getOrCreateComponent(Abst
ractComponentRegistry.java:323)

      at
org.infinispan.factories.AbstractComponentRegistry.invokeInjectionMethod(Abs
tractComponentRegistry.java:251)

      at
org.infinispan.factories.AbstractComponentRegistry$Component.injectDependenc
ies(AbstractComponentRegistry.java:840)

      at
org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
tComponentRegistry.java:225)

      at
org.infinispan.factories.ComponentRegistry.registerComponent(ComponentRegist
ry.java:120)

      at
org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
tComponentRegistry.java:192)

      at
org.infinispan.factories.AbstractComponentRegistry.getOrCreateComponent(Abst
ractComponentRegistry.java:323)

      at
org.infinispan.factories.AbstractComponentRegistry.invokeInjectionMethod(Abs
tractComponentRegistry.java:251)

      at
org.infinispan.factories.AbstractComponentRegistry$Component.injectDependenc
ies(AbstractComponentRegistry.java:840)

      at
org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
tComponentRegistry.java:225)

      at
org.infinispan.factories.ComponentRegistry.registerComponent(ComponentRegist
ry.java:120)

      at
org.infinispan.factories.AbstractComponentRegistry.registerComponent(Abstrac
tComponentRegistry.java:192)

     at
org.infinispan.factories.InternalCacheFactory.bootstrap(InternalCacheFactory
.java:92)

      at
org.infinispan.factories.InternalCacheFactory.createAndWire(InternalCacheFac
tory.java:78)

      at
org.infinispan.factories.InternalCacheFactory.createCache(InternalCacheFacto
ry.java:62)

      at
org.infinispan.manager.DefaultCacheManager.createCache(DefaultCacheManager.j
ava:510)

      at
org.infinispan.manager.DefaultCacheManager.getCache(DefaultCacheManager.java
:440)

      at
org.infinispan.manager.DefaultCacheManager.getCache(DefaultCacheManager.java
:409)

      at
org.infinispan.config.ConfigurationValidationTest.testDefaultMemoryGuardConf
iguration(ConfigurationValidationTest.java:100)

 

 

 

-----Original Message-----
From: infinispan-dev-bounces at lists.jboss.org
[mailto:infinispan-dev-bounces at lists.jboss.org] On Behalf Of Vladimir
Blagojevic
Sent: Friday, January 14, 2011 11:05 AM
To: infinispan -Dev List
Subject: Re: [infinispan-dev] ISPN-863 - Thoughts / Questions

 

Hey David,

First of all kudos for taking on such a non-trivial task!

On 11-01-14 12:22 AM, david marion wrote: 

1.      Modify configuration in some way so that the following can be
specified:

a.       The percentage value of used JVM memory (i.e. 95) at which entries
should be evicted to try and avoid an OOM error.

b.      The number of items that should be evicted when memory reaches this
threshold

2.      Modify LRU and LIRS Eviction class so that the accessQueue member
can be accessed by the new Eviction class so that two access queues don't
have to be maintained.

3.      Create a new Eviction class, a subclass of  LIRS, where the
accessQueue is used from the Eviction strategy the user specifies and the
for loop in the execute method is exited when the evicted set equals value
from 1.b above.

4.      Modify DataContainerFactory.construct() to call
DefaultDataContainer.boundedDataContainer() regardless of eviction policy.
This will always create a BoundedConcurrentHashMap


I don't think you have to extend LRU and LIRS, as long as you implement
EvictionPolicy you are fullfilling the contract. What extending LRU and LIRS
can do is give you some order in selecting proper elements for eviction. I
think the precise technical term in research literature is "eviction
precision". 




1.       

2.      Create an instance of the new Eviction class in each segment.

3.      Modify BoundedConcurrentHashMap.Segment put and replace methods such
that when new values are going to be put into the Segment, the memory usage
is checked and the execute method is called on the new Eviction class.


Sounds right!




1.       

 

Questions:

 

1.      What are the implications of using a BoundedConcurrentHashMap
instead of a ConcurrentHashMap when maxEntries is set to -1?


I think none except you turn on eviction by using BoundedConcurrentHashMap.




1.       

 

Thoughts

 

1.      This will not guarantee that an OOM error does not occur. It will
attempt to guard against an OOM caused by putting new values into the cache.
This will probably be more effective when the cache is being used in
client/server mode, and less effective when used in embedded mode as to
other code running in the JVM.

 

 

-- Dave Marion

 


Cheers,
Vladimir

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