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Memory Leak In PermGen

frank_punzo
Guide

Hello All, 

I have an application that I suspect has a memory leak in permgen (based on Permgen OOM condition and viewing the Permgen heap graph over time). I'm wondering if there's a way using Dynatrace's memory trending snapshot or even the deep memory analysis to find out if a specific objects in the report is in Permgen. Or, is there a way to view all the objects that are currently in permgen? 

 

Thanks, 

Frank

 

5 REPLIES 5

andreas_grabner
Dynatrace Guru
Dynatrace Guru

Hi Frank

We have a great Memory Diagnostics Feature in dynatrace - check out my latest blog post which is a How-To Guide: http://apmblog.compuware.com/2014/10/28/hands-tutorial-5-steps-identify-java-net-memory-leaks/

I will double check with engineering - but - afaik - there is no option to know which objects are in which heap. However - if you want to find leaking objects (regardless of the heap) our memdump feature is perfect for that

Andi

manfred_heching
Participant

hi,

unfortunately we currently have no way to get this information from the JVMTI interface. I agree that it would be really nice to have it.

best

manfred

This would be a nice function to have... obviously I have just had this same issue!!

sreerag_mooleka
Inactive

We see a similar issue in one of our application. We first noticed increase in loaded classes over time and similar pattern for Perm Gen used.

We dint let the Perm Gen go OOM and stopped the test.

We also saw response increase and is mainly due to suspension(GC) and sync time. Thread analysis showed too many threads waiting on single thread which is doing class loading.

I think perm gen is used to store class definitions, will DT mem dump include details of perm gen?

We also see high number of unloaded classes 1 hour into the test.

We are trying to find why this many class loading and unloading is happening.

-Sreerag

sreerag_mooleka
Inactive

Here is the time breakdown chart we created in Splunk with purepath data used for the analysis.

Here is the link to RFE for this feature in Dynatrace Re: RFE: Time breakdown chart similar to layer breakdown

-Sreerag