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Replies:
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Last Post:
Nov 3, 2009 12:06 PM
by: vinu.josey_968
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Posts:
9
Registered:
2/4/09
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Usecase count Zero but Dead Count greater than Zero
Posted:
Feb 4, 2009 1:26 PM
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I have done some memory analysis for our J2EE application running in Websphere 5.1 with IBM JDK 1.4.x in Windows Environment. I was capturing Profiler information from a Linux pc ( snapshot details are difficult to handle in windows ). After my analysis the Snapshot details shows some application class that we developed have Dead Count over 2000 but Use case Count 0 and Heap Count 0. How this is possible ? I am confused.
is there anything that I am missing. Any explanation will be greatly appreciated.
Please refer to the attached html page I have obtained from snapshot.
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Posts:
39
Registered:
10/16/07
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Re: Usecase count Zero but Dead Count greater than Zero
Posted:
Feb 4, 2009 1:42 PM
in response to: bhabatosh.chowd...
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Helpful |
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Hello,
The good news is you're not leaking any of those instances. A brief description of the different counts available:
'Heap Count' represents the total number of instances that are live in the heap.
'Use Case Count' represents the number of instances allocated (and still live) since you started your use case.
'Dead Count' represents the number of instances allocated since you started your use case that have been reclaimed by the garbage collector.
The sequence of events was probably similar to the following:
- you started a use case,
- then allocated 2000 instances to work with (during your use case, you would have seen the 'Use Case Count' grow),
- then finished working with them,
- then the garbage collector reclaimed them (the 'Use Case Count' drops as instances are reclaimed by the garbage collector, and the 'Dead Count' goes up).
Cheers!
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Posts:
9
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2/4/09
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Re: Usecase count Zero but Dead Count greater than Zero
Posted:
Feb 4, 2009 1:48 PM
in response to: Stefan
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thanks for the explanation. too lazy to read the manuals. makes sense now.
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Posts:
3
Registered:
10/31/09
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Recorded Count and Heap Count
Posted:
Oct 31, 2009 4:12 PM
in response to: bhabatosh.chowd...
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Hi,
I have done some memory analysis for J2EE application in WebLogic10.3. After investigating the snapshot, I found that Recorded Count and Heap Count and Recorded Memory and Heap Memory, in the instance view are showing same. Is there any difference between these two ?
For a a particular object the result is
Recorded Count - 119
Recorded Memory - 22,848
Heap Count - 119
Heap Memory - 22,848
Dead Count - 1,036
Dead Memory - 198,912
Keep Alive size - 222,456
Is Recorded Count & Usecase Count same?
Any explanation will be greatly appreciated.
Thanks
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Posts:
171
Registered:
3/21/07
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Re: Recorded Count and Heap Count
Posted:
Nov 1, 2009 9:03 AM
in response to: vinu.josey_968
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Yes, they are different. Heap Count/Memory consists of all of the objects that are reachable in the Java heap space at the time that the snapshot was taken. Recorded Count/Memory consists of all of the objects that JProbe observed during the recording session that remained reachable (that is, were not garbage collected).
These will be different if and when there are reachable object instances in the Java heap that were created before your recording session starts. We usually recommend that you allow your application server to start and your application to "warm up" before you start recording. This allows you to eliminate the set of stable, long-term objects from the "recorded" set and to focus your investigation on objects created during your use case.
In your example all of the instances of the given class appear to have been created during your recording session.
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Posts:
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Registered:
10/31/09
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Re: Recorded Count and Heap Count
Posted:
Nov 3, 2009 12:06 PM
in response to: SHodgins
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Thanks for the reply.
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