Question - if the tenured space fills up in the middle of a CF request, will GC pause everything and try to clear the Heap and pickup where it left off, or will the server run out of Heap space?
Either of those can and do happen. Yes in any major GC the other threads are stop while the GC clears the street so-to-speak. But, if the GC runs into any problems and heap can't be cleared out, most JVMs will try to use some permanent space as a last ditch effort. Sometimes that still isn't enough and the JVM locks up with the Java out of memory errors. With a serious memory leak, you probably get several GC pauses during the course of the day and then the final GC that can't run fully that brings down the box. As you got from the article JVM tuning is great stuff but it's not going to work in this case because you would only make the memory leak problem worse. So the cfc in question really has to be refactor in some way to finally eliminate that leak. John Mason [EMAIL PROTECTED] 770.337.8363 www.FusionLink.com - ColdFusion and Flex hosting Now offering ColdFusion 8 Enterprise hosting FREE Subversion hosting _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Charlie Stell Sent: Friday, December 14, 2007 2:20 PM To: [email protected] Subject: Re: [ACFUG Discuss] CF8/Garbage Collection/Performance Hey John, that article was pretty much the most useful piece I've read yet on the whole issue - thanks a ton. It looks like there is a memory leak with a cfc that in one request was exceeding the Heap when at a lower size - so it was changed 10 a gig. Now that I read your article, I see that makes the problem greatly worse, as it just allows room for that many more leaks, more work for Garbage collection - which means system pauses... Question - if the tenured space fills up in the middle of a CF request, will GC pause everything and try to clear the Heap and pickup where it left off, or will the server run out of Heap space? On Dec 14, 2007 1:38 PM, John Mason <[EMAIL PROTECTED]> wrote: My article on JVM tuning will answer several of your questions.. http://labs.fusionlink.com/katapult/index.cfm?page=articles/jvmtuning <http://labs.fusionlink.com/katapult/index.cfm?page=articles/jvmtuning> Even if you are running on a non Ent version of CF. You can still use SeeFusion trial (for up to 2 hours) and FusionReactor has a trial as well. When you had or doing the monitor running. What did you see? You have a gig for your heap size. Are you filling that up several times a day? Basically you need to find the problem and fix it CF coding first. Playing around with the JVM could simply make your situation worse. John Mason [EMAIL PROTECTED] 770.337.8363 www.FusionLink.com <http://www.fusionlink.com/> - ColdFusion and Flex hosting Now offering ColdFusion 8 Enterprise hosting FREE Subversion hosting _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Charlie Stell Sent: Friday, December 14, 2007 1:16 PM To: [email protected] Subject: [ACFUG Discuss] CF8/Garbage Collection/Performance Im looking into performance issues with an application running on CF8. One of the things Im checking is the GC , Does anyone know how to pragmatically invoke GC? I know you can manually click GC if you have Server Monitor available in CfAdmin (which I did until the 30 days was up and the Standard Edition limitations kicked in). I know also through Server Monitor you can create alerts that can be based on memory stats. and that this alert can invoke GC. Can this alert be created/managed pragmatically? Based on the JVM Arguments, CF/Jrun will do GC regardless of such alert existing or not - correct? The server has a single 2.40Ghz Xeon3220 proc and 2 gigs of ram Its running Microsoft Window Server 2003/Web Ed. SP2 / IIS / CF8 Standard (8,0,0,176276). Its only use is as a CF8 application server. Java Version is 1.6.0_01. The JVM Arguments are: java.args=-server -Xms1000m -Xmx1000m -Dsun.io.useCanonCaches=false -XX:MaxPermSize=192m -XX:+UseParallelGC -Dcoldfusion.rootDir={application.home}/../ -Dcoldfusion.libPath={application.home}/../lib -Dcoldfusion.classPath={application.home}/../lib/updates ,{application.home}/../lib,{application.home}/../gateway/lib/,{application.h ome}/../wwwroot/WEB-INF/flex/jars,{application.home}/../wwwroot/WEB-INF/cffo rm/jars,c:\\coldfusion8\\cfx\\java\\CFX_PDF.jar Never had to deal with the JVM... so I'll be reading up on it this weekend, but does anyone see any obvious problems with the JVM Arguments? ------------------------------------------------------------- Annual Sponsor - Figleaf <http://www.figleaf.com/> Software To unsubscribe from this list, manage your profile @ http://www.acfug.org?fa=login.edituserform <http://www.acfug.org/?fa=login.edituserform> For more info, see http://www.acfug.org/mailinglists <http://www.acfug.org/mailinglists> Archive @ http://www.mail-archive.com/discussion%40acfug.org/ List hosted by FusionLink <http://www.fusionlink.com/> ------------------------------------------------------------- ------------------------------------------------------------- Annual Sponsor - Figleaf <http://www.figleaf.com/> Software To unsubscribe from this list, manage your profile @ http://www.acfug.org?fa=login.edituserform <http://www.acfug.org/?fa=login.edituserform> For more info, see http://www.acfug.org/mailinglists <http://www.acfug.org/mailinglists> Archive @ http://www.mail-archive.com/discussion%40acfug.org/ List hosted by FusionLink <http://www.fusionlink.com/> ------------------------------------------------------------- ------------------------------------------------------------- Annual Sponsor - Figleaf Software <http://www.figleaf.com> To unsubscribe from this list, manage your profile @ http://www.acfug.org?fa=login.edituserform For more info, see http://www.acfug.org/mailinglists Archive @ http://www.mail-archive.com/discussion%40acfug.org/ List hosted by FusionLink <http://www.fusionlink.com> ------------------------------------------------------------- ------------------------------------------------------------- Annual Sponsor FigLeaf Software - http://www.figleaf.com To unsubscribe from this list, manage your profile @ http://www.acfug.org?fa=login.edituserform For more info, see http://www.acfug.org/mailinglists Archive @ http://www.mail-archive.com/discussion%40acfug.org/ List hosted by http://www.fusionlink.com -------------------------------------------------------------
