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Posted to users@tomcat.apache.org by Darren Kukulka <Da...@connaught.plc.uk> on 2008/09/24 09:37:48 UTC

Tomcat thread blocking

Hi,

 

I've recently observed a scenario in Tomcat 6.0.13 64-bit under SUN JDK
1.6_03 (x64 Windows platform), where a large number of threads show a
status of BLOCKED.

 

Can someone please advise the easiest and most effective way of helping
identify the original cause of the block?....or have I just opened up a
can of worms?!

 

The behaviour is not something I can replicate so I need a method for in
situ investigation, before I have to restart Tomcat to restore service
(after a while Tomcat consumes too much CPU and becomes unresponsive)

 

Any pointers would be much appreciated.

 

Darren Kukulka

Business Applications Architect

Connaught PLC

Tel: 01392 353497

 




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Winner of Partnering Contractor of the Year Award in 2005 and 2007

Tenant Care Scheme of the Year 2007

Please visit our website to see a full list of Connaught's Registered Companies www.connaught.plc.uk/Investors/Registered-Companies

 

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Re: Tomcat thread blocking

Posted by Mark Thomas <ma...@apache.org>.
Darren Kukulka wrote:
> Hi,
> 
> I've recently observed a scenario in Tomcat 6.0.13 64-bit under SUN JDK
> 1.6_03 (x64 Windows platform), where a large number of threads show a
> status of BLOCKED.
> 
> Can someone please advise the easiest and most effective way of helping
> identify the original cause of the block?....or have I just opened up a
> can of worms?!
Get 2 or 3 thread dumps ~20secs apart and analyse them.

> The behaviour is not something I can replicate so I need a method for in
> situ investigation, before I have to restart Tomcat to restore service
> (after a while Tomcat consumes too much CPU and becomes unresponsive)
Thread dumps can be generated whilst Tomcat is running.

Mark


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Re: Tomcat thread blocking

Posted by Johnny Kewl <jo...@kewlstuff.co.za>.
----- Original Message ----- 
From: "Darren Kukulka" <Da...@connaught.plc.uk>
To: <us...@tomcat.apache.org>
Sent: Wednesday, September 24, 2008 9:37 AM
Subject: Tomcat thread blocking


Hi,



I've recently observed a scenario in Tomcat 6.0.13 64-bit under SUN JDK
1.6_03 (x64 Windows platform), where a large number of threads show a
status of BLOCKED.



Can someone please advise the easiest and most effective way of helping
identify the original cause of the block?....or have I just opened up a
can of worms?!



The behaviour is not something I can replicate so I need a method for in
situ investigation, before I have to restart Tomcat to restore service
(after a while Tomcat consumes too much CPU and becomes unresponsive)



Any pointers would be much appreciated.

==============================
Google for VisualVM... its in the later Java versions....
Heap Dumps, Thread Dumps... its like JConsole on steroids ;)

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