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From André Warnier ...@ice-sa.com>
Subject Re: server status reports long request times
Date Wed, 20 Jul 2011 09:06:25 GMT
Michael Südkamp wrote:
> Hello,
> 
>>From time to time we have customers  experiencing Tomcat going to 100% CPU.  
One customer sent us the output from the server status page from the Tomcat 6.0.32 Manager

web-app.
This page reports a lot of HTTP connector requests belonging to a certain client

can you explain "a certain client" ? is it a browser, or some other app ? is it one single

client ? from the point of view of that client, is the request finished, or is the client

still waiting for something ?

  with stage value "S" and "time" values between 1000000 and 3000000 ms, i.e. almost one 
hour.
We don't know what causes the requests to never finish.

The question is : is the request/response really finished ?

  Believe me our web-app is not in a loop.

How do you know that ? We do not believe anything or anyone here without some proof.

Maybe it's a problem with the database but we have already often spend a lot of time to 
analyze
    but couldn't find a problem on our side.

I believe that taking some thread dumps would tell you exactly what Tomcat is doing at 
such times.

Anyway,  isn't Tomcat somehow capable to detect such hanging requests (say requests that take
  longer than a minute) and kill them?

Well, if from the Tomcat point of view the request is not finished, it should not kill it,

should it ? some valid requests/responses may take a long time to finish. How is Tomcat 
supposed to know ?

I studied the HTTP connector reference but haven't found a parameter related to this.

A very long KeepAlive setting may explain connections lingering on. What is your setting ?

The system runs on a Windows Server 2008 R2 and Java 5 (OK we could ask the customer to 
upgrade Java).
> 


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