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Home » Eclipse Projects » Memory Analyzer » Does Heap dump includes Thread dump?(MAT heap dump and thread dumps)
Does Heap dump includes Thread dump? [message #921778] Mon, 24 September 2012 08:15 Go to next message
vishwanath manchala is currently offline vishwanath manchala
Messages: 1
Registered: September 2012
Junior Member
Hi,
I am very new to this forum. Recently i started working on Heap Dump and Thread dumps.
Through a java program i created a .hprof file and when i load this file in Eclipse MAT tool, I see "Thread Overview" section in "Table of contents". Does it mean a Thread dump? If it is a thread dump, then can we say a Heap Dump contains a Thread Dump?

Thx in adv,
Vish
Re: Does Heap dump includes Thread dump? [message #921860 is a reply to message #921778] Mon, 24 September 2012 09:52 Go to previous messageGo to next message
Krum Tsvetkov is currently offline Krum Tsvetkov
Messages: 149
Registered: July 2009
Senior Member
Hi Vish,
Yes, some heap dumps contain also thread information.
HPROF files from JDK 1.6_20 (I think) and above do so.
In MAT you can explore the thread stacks if you open from the query menu "Java Basics" -> "Thread Stacks".
From this view you can then navigate also into the local objects of each thread frame.

IBM system dumps also contain this info.

From what I know HPROF dumps from older JVMs do not contain the info, and also PHD dumps from IBM do not contain it.

Hope this helps.
Krum
Re: Does Heap dump includes Thread dump? [message #923786 is a reply to message #921860] Wed, 26 September 2012 03:38 Go to previous messageGo to next message
Andrew Johnson is currently offline Andrew Johnson
Messages: 119
Registered: July 2009
Senior Member
Quote:
From what I know HPROF dumps from older JVMs do not contain the info, and also PHD dumps from IBM do not contain it.

It is true that PHD files do not contain thread stacks, but javacore files do contain thread stacks (with method information, but no local variables).
The IBM DTFJ feature will combine data from the javacore with the PHD if both are in the same directory. The MAT DTFJ parser will then retrieve the data and MAT can then display the thread stack.
Re: Does Heap dump includes Thread dump? [message #924912 is a reply to message #921778] Thu, 27 September 2012 04:24 Go to previous messageGo to next message
Andrew K is currently offline Andrew K
Messages: 1
Registered: September 2012
Junior Member
Hi guys,

I'm also new to this forum and I have a similiar question: Is it possible to use the MAT to analyze a thread dump only? If yes, how can this be done? Or do I always need a heap dump file which can contain thread stack information as well?

Thanks!
Re: Does Heap dump includes Thread dump? [message #926086 is a reply to message #924912] Fri, 28 September 2012 05:39 Go to previous message
Andrew Johnson is currently offline Andrew Johnson
Messages: 119
Registered: July 2009
Senior Member
You can just read a javacore file from an IBM VM with MAT, but it isn't very useful.
It has a thread stack, a list of classes and classloaders, but no information about instances of classes. I suppose you could write a query which would look at the methods being executed and make a guess as to which program was running.
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