Question Re: Thread Dump vs Heap Dump in Technology Q&A

Thread Dump vs Heap Dump

Former Member — Mon, 31 Mar 2008 15:13:33 GMT

Hi,

The below question are related to J2EE 7.00.

- What is the difference between Thred dump and Heap dump?

- When I go to Config tool then I go to Instance ID.

There are two nodes under the Instance ID, DIspatcher and Server (could be multiple).

I see different tabs on Instance ID and they are Message Server and BootStrap, Server General. There are lots of setting under Server General tab.

My question is that what is the usage of the "Server General" tab?

Please let me know.

I will appreciate your reply.

Regards.

Sume

Re: Thread Dump vs Heap Dump

Former Member — Mon, 31 Mar 2008 22:05:03 GMT

A java engine runs all its work in 'threads' much like WP's in SM50 but unfortunately not so stand alone in 7.0.

A thread dump is a bit like taking a photo of SM50, that is why you will be asked to take 2 or 3 so as to see what sticks in threads for a while.

A java engine uses memory to store all its objects. Most memory is a single area called heap. A heap dump lists all objects in memory at the time.

Thread dump = activities working/waiting

Heap Dump = objects used

As for the configtool, I do not have one in front of me to double check but I believe you are looking at the general settings as opposed to local instance settings. So you can set parameters at a local level using an instance number or for all instances by setting it as a general setting. Quite a few settings that are set at the local level are set globally anyway so be aware that that may be the case.

Re: Thread Dump vs Heap Dump

Former Member — Tue, 01 Apr 2008 12:05:22 GMT

Hi Graham,

This question is realted to the same post but slightly diffrent. Thread dumps<>.phd & Javacore<>.txt files are filling up the server0 folder at server level. Can't we disable this option?

Please tell me if you know the procedure.

Regards,

Sree

Re: Thread Dump vs Heap Dump

Former Member — Tue, 01 Apr 2008 15:27:51 GMT

Thank you for the reply Graham.

One Clarification -

When I set anything at Server General tab for an Instance then it gets reflected for all the server(s) under that instance only. Correct?

Which one will supercede. Local or Global. I mean If X=5 is set at Server General tab for an Instance and X=3 is set at a server<n> under the same Instance then the value of X will be 5 or 3.

Last question is that if X=5 is set at Sever General then am I going to see the X=5 at server<n> as well or it will not be visible unless I want to overwrite it with X=3. I am seeing some weird results so I just wanted to confirm the fundamental.

Your help will be greately appreciated.

Thank you.

Sume

Re: Thread Dump vs Heap Dump

Former Member — Tue, 01 Apr 2008 16:17:38 GMT

should you create a new question and mark this as answered?

you can disable them, but really you should fix the problem causing them.

You disable them differently depending on system, its not something I have ever done but doing a google on Javacore.txt disable gives you ideas.

Local settings override global settings

There is some wierd things if you start saving not online the the config tool but also in the offline config tool (the pencil button in the configtool)

Edited by: Graham Newport on Apr 1, 2008 6:18 PM

Re: Thread Dump vs Heap Dump

Former Member — Tue, 01 Apr 2008 19:56:22 GMT

Thank you again Mr. Graham.

I do not know if I had to open a new question. That can be debatable.

Why I did not do it because I think they were related and my second question arised from your first reply. I do not think it was appriate to create new one in my openioun.

Anyways, I am pleased with your replies and I am closing this thread.

Regards.

Sume

Re: Thread Dump vs Heap Dump

Former Member — Tue, 01 Apr 2008 21:03:06 GMT

When I set anything at Server General tab for an Instance then it gets reflected for all the server(s) under that instance only. Correct?

No, its the other way round, anything you set in the General Tab of the Server ID get reflected finally.