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From Denis Magda <dma...@gridgain.com>
Subject Re: Unexpected heap usage by GridDhtPartitionTopologyImpl
Date Wed, 06 Apr 2016 15:00:58 GMT
Hi Tolga,

GridDhtPartitionTopologyImpl contains list of partitions that belong to 
a specific node. In case of offheap caches each partition (concurrent 
map) contains set of wrappers around keys->values, stored offheap. The 
wrapper holds information that's needed to unswap a value or a key to 
Java heap from offheap when required by a user application.
So Ignite requires extra space for internal needs even when offheap mode 
is used.

I would recommend you trying to reduce 
the size of the queue that keeps deleted entries for internal needs as well.

BTW, could you explain what columns from your screenshot mean exactly? 
What tool did you use to create the memory snapshot?


On 4/6/2016 3:02 PM, Tolga Kavukcu wrote:
> Hi everyone,
> I use partitioned ignite cache for a very dynamic data. Means that 
> there are many updates,deletes and puts with around 5m~ row.
> So to avoid gc pauses i use off-heap mode. But when i analyse heap i 
> see that count and heap size of 
> /org.apache.ignite.internal.processors.cache.distributed.dht.GridDhtPartitionTopologyImpl/
> increasing constantly.
> Please see attached screenshots taken from mat heap dump.
> <bean class="org.apache.ignite.configuration.CacheConfiguration" 
> name="DEFAULT"> <property name="atomicityMode" value="ATOMIC" /> 
> <property name="cacheMode" value="PARTITIONED" /> <property 
> name="memoryMode" value="OFFHEAP_TIERED" /> <property name="backups" 
> value="1" /> <property name="affinity"> <bean 
> class="org.apache.ignite.cache.affinity.fair.FairAffinityFunction"> 
> <constructor-arg index="0" type="int" value="6"/> </bean> 
> </property><property name="writeThrough" value="false" /> <property 
> name="writeBehindEnabled" value="false" /> </bean>
> Thanks for helping out.
> There are totally 1.2 heap used by GridDhtPartitionTopologyImpl, 
> almost equals to my data size. Do you think that there are problems 
> with configuration.
> *Tolga KAVUKÇU
> *

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