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Problem determination from heapdump ?

Kevin Ramer (4.5k6171190) | asked Aug 29 '12, 3:32 p.m.

RTC instance comes crashing down due to OutOfMemory exception.  Analysing the heapdump

A Linked List Data Structure Detected.
3,591,650,456 bytes (76.85 %) of Java heap is used by 255,780 instances of java/util/LinkedList$Entry
Contains the following object:
- 255,779 instances of java/lang/Object holding 3,579,362,328 bytes

I *think* this means that the average is 139,933 bytes for those 255,779 items but together they're hitting 3.5G or there abouts.

In my jazz logs:

2012-08-27 15:01:51,854 [http-rtp-rtc8%2F9.42.60.213-9443-Processor1611]  WARN LeakWrapperLogger                                   - Aborting transact
ion Connection #34820051 has 1 open statements
2012-08-27 15:01:51,861 [jazz: AsynchronousTaskRunner-3] ERROR                             - CRJAZ1451I An exception occurred
while executing the task "ItemCleanupTask", contributed by component "".  The task will be rescheduled.

2012-08-27 15:05:53,461 [jazz: AsynchronousTaskRunner-2] ERROR nternal.service.BuildForgeEventPollerScheduledTask  - Error running event poller task.
        at java.lang.ref.ReferenceQueue.<init>(
        at java.util.WeakHashMap.<init>(

And a few more.  On the database side the nearest thing to a "problem" is:

2012-08-28-   Instance:rtcinst1   Node:000
PID:11468960(db2agent (RTCDB8) 0)   TID:107304   Appid:
data protection services  sqlpgResSpace Probe:2860   Database:RTCDB8

ADM1823E  The active log is full and is held by application handle "60621..".
Terminate this application by COMMIT, ROLLBACK or FORCE APPLICATION.

repeated several times.

This application also died in similar fashion on Aug 14 and I upped the JVM by 1G.

By the way, I've been monitoring our server farm with a self-written tool that gets the basic server info (jvm used, jvm free, jvm max, uptime) each 1/2 hr and this one's timeline did not show any usage at or near the max of its potential JVM.


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Kevin Ramer (4.5k6171190) | answered Nov 09 '12, 8:42 a.m.
A Linked List Data Structure Detected.
3,374,476,848 bytes (73.39 %) of Java heap is used by 254,114 instances of java/util/LinkedList$Entry
Contains the following object:
- 254,113 instances of java/lang/Object holding 3,362,284,984 bytes

another one bites the dust.  My suspicion is that BIRT reports are to blame as I often see java.util.LinkedList at the  top of stack traces in the "Active Services" on finding "postRenderReport" ...

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