OutOfMemoryError after 88MB on Win2K / Tomcat 4.0.4

[JB...@efcocorp.com]

We are running a heavily XML-based application on Tomcat 4.0.4 on a dual 
P4 1.4 GHz box with 4GB of RAM.  With 9 users hitting the application 
continuously, we experience OutOfMemoryErrors after tomcat.exe gets up to 
around 88MB of usage.

Has anyone else experienced strange happenings with Tomcat on Win2K JDK 
1.3.1 under load?  We're wondering if the JVM is doing this, if there's 
something in Tomcat that is causing the memory to continuously creep up 
and never go down significantly, or if we're just really overlooking 
something in our application framework that is causing objects to not go 
out of scope.  We haven't experienced this problem like this on other 
platforms (Linux and OS/400) and IBM is testing this application and not 
seeing the same kinds of results in WebSphere.

I'd appreciate any feedback from other XML users here...we have a go-live 
date just a few days off and these problems are making my life very 
difficult.  I'd like to at least be able to explain the situation, even if 
it is our fault.  Not knowing is very frustrating.

Thanks for your help!

Jon Brisbin
Sr. App. Developer
EFCO Corporation
www.efcocorp.com
417.235.3193 x2687

RE: OutOfMemoryError after 88MB on Win2K / Tomcat 4.0.4

[Michael Schulz <mi...@mschulz.net>]

Have you changed the default JVM options for Tomcat?

Here are the default JVM options:

-Xmsn
Specify the initial size, in bytes, of the memory allocation pool. This
value must be a multiple of 1024 greater than 1MB. Append the letter k or K
to indicate kilobytes, or m or M to indicate megabytes. The default value is
2MB. Examples:
       -Xms6291456
       -Xms6144k
       -Xms6m

-Xmxn
Specify the maximum size, in bytes, of the memory allocation pool. This
value must a multiple of 1024 greater than 2MB. Append the letter k or K to
indicate kilobytes, or m or M to indicate megabytes. The default value is
64MB. Examples:
       -Xmx83886080
       -Xmx81920k
       -Xmx80m


There are other JVM options available.  They are documented here:

http://java.sun.com/j2se/1.4.1/docs/tooldocs/windows/java.html

For tomcat 4.x on linux, I made my changes in the setclasspath.sh file (I'm
sure others have an opinion on this, but it works for me) by adding a
statement at the top of the file:
	JAVA_OPTS="-verbose:gc -Xms64m -Xmx128m"

(The -verbose:gc prints a message to catalina.out whenever a gc occurs).

hth,
Mike Schulz


-----Original Message-----
From: JBrisbin@efcocorp.com [mailto:JBrisbin@efcocorp.com]
Sent: Thursday, October 03, 2002 4:37 PM
To: tomcat-user@jakarta.apache.org
Subject: OutOfMemoryError after 88MB on Win2K / Tomcat 4.0.4


We are running a heavily XML-based application on Tomcat 4.0.4 on a dual
P4 1.4 GHz box with 4GB of RAM.  With 9 users hitting the application
continuously, we experience OutOfMemoryErrors after tomcat.exe gets up to
around 88MB of usage.

Has anyone else experienced strange happenings with Tomcat on Win2K JDK
1.3.1 under load?  We're wondering if the JVM is doing this, if there's
something in Tomcat that is causing the memory to continuously creep up
and never go down significantly, or if we're just really overlooking
something in our application framework that is causing objects to not go
out of scope.  We haven't experienced this problem like this on other
platforms (Linux and OS/400) and IBM is testing this application and not
seeing the same kinds of results in WebSphere.

I'd appreciate any feedback from other XML users here...we have a go-live
date just a few days off and these problems are making my life very
difficult.  I'd like to at least be able to explain the situation, even if
it is our fault.  Not knowing is very frustrating.

Thanks for your help!

Jon Brisbin
Sr. App. Developer
EFCO Corporation
www.efcocorp.com
417.235.3193 x2687


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