One other factor in upgrading to Tomcat 5.0.x: I'm using JSTL for my app, so that will mean a JSTL 1.1 JAR upgrade, too. I haven't tested anything with it yet.
% --- Peter Lin <[EMAIL PROTECTED]> wrote: > if you can upgrade to tomcat5, I would recommend it. > the reason I suggest this is TC5 has the new status > servlet, which will tell you how much heap is > actually in use currently. > > > the JVM will not release memory back to the OS that > is true. in terms of performance the biggest > indicator of poor performance is the rate at which > the heap grows and the frequency of full GC. > > > Applications that are well behaved should result in > regular intervals of full GC. Poor performing > applications wiill cause erratic and frequent full > GC. Even if you can't upgrade to TC5, it might be > worth it to d/l and install it. Once you have it > installed, you can use JMeter to view the server > load and the memory usage pattern. > > I hope that helps. > > peter > > > > Michael Duffy <[EMAIL PROTECTED]> wrote:I recently > had a problem with a Windoze server hanging > up due to memory problems. > > I've got Tomcat 4.1.29 installed to run as a service > under JDK 1.4.1_05 on this Windows 2000 server. The > Tomcat memory settings on startup are -Xms64m and > -Xmx1024m. The server has 512MB of physical RAM > installed. The Windoze task manager says Tomcat is > sitting at ~128MB of memory. > > My understanding is that Java's garbage collection > will reclaim heap-allocated memory to the JVM, but > not > necessarily to the OS. Is this true? What this means > is that a Windoze server admin could look at the > task > manager and see a large memory usage for Tomcat, but > that doesn't necessarily reflect Tomcat's current > usage. > > It's more like a high water mark on a pier: it'll > show > the highest value that Tomcat has used, but the real > value will be lower if the garbage collector runs > and > the tide goes out. If you read a lot of objects into > session you could end up with a big high water mark. > > The application is a JSP front end with a single > controller servlet that interacts with an Oracle > database. The only data members in the servlet are > some read-only map that are initialized on startup. > There are some session data that are maintained for > certain user requests, but the rest are all > stateless > request/response. > > The server admin is saying that the problem is > Windoze > memory management. When a new process starts up > outside of Tomcat, it could be that memory isn't > reachable, and the new process hangs. > > We're going to increase the virtual page size on > Windoze and change the startup settings for the > Tomcat > service to -Xms256m and -Xmx1536m. > > So my questions are: > > (1) Is my understanding of the interaction between > the > JVM and OS memory management correct? > (2) Are there any other tuning settings for Tomcat > that I need to look at? > > Thanks - % > > > > > > __________________________________ > Do you Yahoo!? > Friends. Fun. Try the all-new Yahoo! Messenger. > http://messenger.yahoo.com/ > > --------------------------------------------------------------------- > To unsubscribe, e-mail: > [EMAIL PROTECTED] > For additional commands, e-mail: > [EMAIL PROTECTED] > > > > --------------------------------- > Do you Yahoo!? > Friends. Fun. Try the all-new Yahoo! Messenger __________________________________ Do you Yahoo!? Friends. Fun. Try the all-new Yahoo! Messenger. http://messenger.yahoo.com/ --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
