sharad bhushan wrote:
> to keep this updated
> 
> The Issue was cache - SoftReference. 
> http://bugs.sun.com/bugdatabase/view_bug.do;jsessionid=cfd518f51afc7780e5188276b5f9?bug_id=6912889
> 
> The monitoring ran for month now and the application is stable. we changed 
> the SoftRefLRUPolicyMSPerMB.

That's a bummer.  And if true, it explains alot.


> 
> Sharad
> 
> 
> ________________________________
> From: Adam Heath <[email protected]>
> To: [email protected]
> Sent: Fri, 7 May, 2010 1:28:08 AM
> Subject: Re: Is there a possible memory issue causing objects to stay in old 
> generation for long - ofbiz and javolution
> 
> sharad bhushan wrote:
>> Hello Everyone,
>>
>> I have been trying to get the understanding of memory allocation when 
>> debugging the  load and memory issue in our ofbiz instance
>>
>> Here is the snap shot of our gc log after three days of running and this had 
>> been continuing for next two days and went  low 
>> eventually not responding.   This Full GC run as below was continuous with 
>> tenured memory not clearing and Full GC kept running all
>> together for 2 days with breaks for few hours, it still survived  "out of 
>> memory" as young generation was releasing on Full GC.
>>
>> 328821.354: [Full GC 328821.354: [Tenured: 1048576K->1048575K(1048576K), 
>> 2.9016030 secs] 1520444K->1087815K(1520448K), [Perm : 
>> 49067K->49050K(49152K)], 2.9017140 secs] [Times: user=2.90 sys=0.00, 
>> real=2.90 secs] 
>> 328825.334: [Full GC 328825.334: [Tenured: 1048575K->1048575K(1048576K), 
>> 2.4392020 secs] 1520447K->1097197K(1520448K), [Perm : 
>> 49054K->49054K(49152K)], 2.4393150 secs] [Times: user=2.43 sys=0.00, 
>> real=2.44 secs] 
>> 328828.673: [Full GC 328828.673: [Tenured: 1048575K->1048575K(1048576K), 
>> 2.4696630 secs] 1520447K->1107798K(1520448K), [Perm : 
>> 49063K->49063K(49152K)], 2.4697760 secs] [Times: user=2.46 sys=0.00, 
>> real=2.46 secs] 
>>
>> 403173.352: [Full GC 403173.352: [Tenured: 1048576K->1048576K(1048576K), 
>> 2.7718690 secs] 1520447K->1252656K(1520448K), [Perm : 
>> 49417K->49417K(49664K)], 2.7719880 secs] [Times: user=2.77 sys=0.00, 
>> real=2.77 secs] 
>> 403176.958: [Full GC 403176.958: [Tenured: 1048576K->1048576K(1048576K), 
>> 2.7772930 secs] 1520448K->1264672K(1520448K), [Perm : 
>> 49421K->49421K(49664K)], 2.7774020 secs] [Times: user=2.78 sys=0.00, 
>> real=2.77 secs] 
>> 403180.713: [Full GC 403180.713: [Tenured: 1048576K->1048576K(1048576K), 
>> 2.7374900 secs] 1520447K->1267832K(1520448K), [Perm : 
>> 49426K->49426K(49664K)], 2.7376110 secs] [Times: user=2.73 sys=0.00, 
>> real=2.74 secs] 
>>
>> With above said i would like to give the top classes on doing jmap -histo
>> javolution FastMap$Entry - ~240MB - nearly 4,900,000 objects
>> javolution FastMap$Entry[]  - ~120MB 
>> javolution HashMap$Entry - ~90MB  
> 
> You have to be very very careful.  All FastMap instances, and all
> their keys/values, and everything else they point to, including
> various chained classloaders, then the classes loaded by those
> classloaders, and all the static references in *those* classes, etc.
> 
> I've found that the various memory graph walking tools don't really
> handle finding the *correct* top-level items to show.
> 
> 
>> The java max heap  (-Xmx) is 1.5GB. 
>>
>> the tenured - old gen is ~1000MB and the above three elements are 50% 
>> occupied, certainly after drilling through few heap dumps it describes of 
>> above three classes.
>>
>> The tenured space does not get cleared, I am looking to suspect the FastMap, 
>> specifically, we have been using ofbiz cache too.
>>
>> Can there be any inputs or observation about the possible issue in memory or 
>> javolution, any directions for the above description would certainly help me.
>>
>> Regards
>> Sharad
>>
>>
>>
> 
> 

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