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From Tolga Kavukcu <kavukcu.to...@gmail.com>
Subject Re: Unexpected heap usage by GridDhtPartitionTopologyImpl
Date Thu, 07 Apr 2016 12:43:18 GMT
Hi Denis,

IGNITE_ATOMIC_CACHE_DELETE_HISTORY_SIZE parameter seems like decreased heap
usage. I will run longer tests to check heap behaviour.

Also i need another help with thread's created by ignite. I found out that
ignite creates a cleanup thread named "ttl-cleanup-worker" for each cache.
But when cache is destroyed, clean up thread does not deleted. Instead it
waits sleeping state at all.

My first question is that , is it possible to decrease thread count with a
configuration, like "thread pool with x threads" for all caches.
Secondly, is "unremoved threads" are expected behaviour.

Thanks.

On Thu, Apr 7, 2016 at 2:40 PM, Denis Magda <dmagda@gridgain.com> wrote:

> Hi Tolga,
>
> GridDhtPartitionTopologyImpl is created per cache. If you destroy a cache
> this object should be GCed. However you should use cache.destroy() for that.
>
> Please also make sure that you make "live set" heap dumps only. Try to
> perform GC explicitly before making the dump because a collector may clean
> dead objects much later depending on its heuristics.
>
> --
> Denis
>
> On 4/7/2016 8:27 AM, Tolga Kavukcu wrote:
>
> Hi Denis,
>
> Thanks for the response. I will try IGNITE_ATOMIC_CACHE_DELETE_HISTORY_SIZE parameter.
> The screnshots taken from eclipse memory analyser which opens and analyses
> heap dump. I understand heap requirement for wrapping and indexing off-heap
> entry positions. But also found out that instances of *org.apache.ignite.internal.processors.cache.distributed.dht.GridDhtPartitionTopologyImpl
> *is constantly increasing within jvm.
>
>
> I also create and destroy so many small caches during the lifecycle, do
> you think that it is possible to destroyed caches leaves a footprint in
> heap.
>
> The previous scrreenshots was dominator tree view of memory analyser. I
> attached again with headers.
>
>  You can see that each of GridDhtPartitionTopologyImpl uses 20mb~ heap.
> And there are 72 instances of GridDhtPartitionTopologyImpl living.
>
> Also i attached screenshots of leak suspect report of memory analyzer,
> which is taken periodically. You an see that instances of *GridDhtPartitionTopologyImpl
> keeps increasing. *
>
> Any ideas or suggestions?
>
> On Wed, Apr 6, 2016 at 6:00 PM, Denis Magda <dmagda@gridgain.com> wrote:
>
>> 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
>> IgniteSystemProperties.IGNITE_ATOMIC_CACHE_DELETE_HISTORY_SIZE. This is the
>> size of the queue that keeps deleted entries for internal needs as well.
>> https://apacheignite.readme.io/v1.5/docs/capacity-planning
>>
>> BTW, could you explain what columns from your screenshot mean exactly?
>> What tool did you use to create the memory snapshot?
>>
>> --
>> Denis
>>
>>
>>
>> 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*
is
>> 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 *
>>
>>
>>
>
>
> --
>
> *Tolga KAVUKÇU *
>
>
>


-- 

*Tolga KAVUKÇU*

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