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From: "Bob Riaz" <briaz@mum.edu>
To: "Tomcat Users List" <users@tomcat.apache.org>
Subject: RE: [OT] Tomcat causing high CPU load
Date: Thu, 8 Nov 2007 11:29:08 -0600
Message-ID: <JIEFLFNKLJCNLLACBFOOOEMDCDAA.briaz@mum.edu>
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Thanks. StringBuilder seems to be the most popular suggestion! I'm going =
to implement this and report on any changes I see in Tomcat's behavior.=20
I'm also looking at other possiblities, such as Tomcat's I/O activities =
causing thrashing if I/O is excessive. Would anybody know how I could =
monitor Tomcat's I/O activities?=20
Also, is there a way to configure Tomcat so that a connection times out =
after a certain period of time?
Thanks to everyone for your attention and help.

Bob=20

-----Original Message-----
From: Kev Jackson [mailto:foamdino@gmail.com]
Sent: Wednesday, November 07, 2007 11:14 PM
To: Tomcat Users List
Subject: Re: [OT] Tomcat causing high CPU load


Hi,
 From a programmatic point of view


> Many thanks for all the suggestions. I found a simple tool called =
StackTrace from http://www.adaptj.com/root/main/tracehowtos#ht0 to help =
me take thread dumps from Tomcat. I found when the CPU load was high =
that there was a thread from the suspect web app running. In contrast, =
thread dumps taken when CPU load was normal showed no such threads. The =
line that the web app thread was running at is a simple - data +=3D =
"\n"; - this is in a loop collecting form data from hidden vars created =
by JavaScript code. It's been suggested by ny colleagues that the JVM =
could be running out of memory since a new String object is created for =
each +=3D. The String data ends up being very long anyway. Any thoughts =
on this would be appreciated.
> Also, would anyone know how to monitor Tomcat's I/O activities? I =
understand that thrashing could be a drain on memory resources.
> Thanks again for everybody's help!

You could replace the data +=3D "\n" code with a StringBuilder (Java6) =
or=20
a StringBuffer - this would reduce the number of intermediate objects=20
being created quite significantly

Kev

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