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From br1 <>
Subject Re: JK and IIS - troubles?
Date Thu, 09 Oct 2008 21:10:20 GMT

Hello again Rainer,

Rainer Jung-3 wrote:
> But if you are really actively using 300 connections, it means there are
> 300 requests processed in parallel inside Tomcat. So you should first
> check with the thread dump, what those are actually doing, and whether
> it's a good idea to send even more requests there. 
Definitely it is not a good idea. Details and a thread dump below. 

Rainer Jung-3 wrote:
> If the web server
> can't acquire another connection from the pool, further requests should
> fail, not block.
Totally agreed. 
Please note, if I was not clear enough before, that my goal is to avoid that
any failing Tomcat application hangs the whole web server (and site). 
This should not happen at all, whatever settings in the JK connector.. I am
not going to solve this particular application's problem before the JK
connection works properly - though I will send thread dumps as appropriate
to the application developer, and drink a beer with him when this is all
over.. but this is another story.

I changed the settings just a bit, so now the IIS side JK connections are
limited to 50 instead of the previous 250 and 300. 

I managed to schedule a few thread dumps (3, with a 5 seconds interval) and
a Tomcat restart in case of troubles, and just implemented some more
logging. I kept the faulty Tomcat app running all day. 
There were three failures today, but thanks to the logging I just added I
can be only sure about the last one, and it was blocking the whole site. As
usual, a simple Tomcat restart cured the whole site hang. 

The HTTP error the application gives, as well as the error of the site root
(that BTW is a static html page) simply is: The connection with the server
was terminated abnormally
Very strangely, an (automated) netstat in this last event shows just four
(4) ESTABLISHED connections on the Tomcat server from the IIS server when
everything was failing.

I am enclosing the last thread dump here, hoping it could shed some light.

Please let me know - and forgive me - if I forgot to provide additional
information, configuration files, etc.
Some of my colleagues use to tell me: "Someone, somewhere in the world, had
some problem using something. Can you please solve this."

Thanks for your help,
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