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From "Halstead, Chris" <>
Subject RE: Tomcat and multi-processor support
Date Wed, 30 Apr 2003 15:23:38 GMT
The behaviour of your app _shouldn't_ differ between machines with differing numbers of CPUs.
 Java is multithreaded by nature so I would wager that the issue lies somewhere in your code,
possibly a thread synchronization issue that does not manifest in single-cpu environments.
 Without seeing your code or having a more detailed explanation of its' flow it is very difficult
to diagnose what may be wrong.  From your description it sounds like you're storing each users'
session object in a static HashMap?

There are not different versions of Tomcat for single vs. multi-processor (CPU) use.  There
are also not different versions of Apache in this regard, but there are different _processing_
modules available (at least with Apache 2.x) - a threaded process module (each process handling
numerous requests via threading) and a multi-process module (one process per concurrent request).

Hope this helps,


> Hi,
> I'm currently testing a webapp which runs on Tomcat 4.0.6 on 
> a W2K multi-processor (dual xeon) platform. The JDK installed 
> is veriosn 1.3.0 from Sun. The webapp runs fine under NT 4 
> server and W2K, server both single processor architecture. 
> The webapp consists of a login module for user 
> authenticartion. When a user is logged in he/she can access 
> jsp's. On each jsp a authorization check is made. Here's 
> where the problem occurs. When a user logs in a hasmap is 
> created in which a webuser object is put in together with a 
> session object. This way, each user that is logged in can be 
> verified. So, when the authorization check on a jsp is made 
> on the webuser object, the webuser object seems to be null. 
> Is this a multi-processor issue with Tomcat? As I was told 
> there seem to be 2 different versions of the Apache httpd 
> server, single- and multi-processor.
> With kind regards,
> Michiel.

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