On 21/10/2011 13:12, Bob DeRemer wrote: > Thanks Mark, I appreciate the offer. Let me dig into a bit today - > based on your steps. if I can't get anywhere, I'll gladly take you > up on your offer. What is the best way to communicate out-of-band if > I need to get you a snapshot?
Bob and I took at look at this off-list using the standard approach for finding web-app reload memory leaks [1] and found what appears to be an issue with Tomcat's memory leak protection for the http keep-alive thread. Tomcat only clears the WebappClassLoader from the http keep-alive thread if the thread is still running. It should clear it in all circumstances. Ill be updating Tomcat to address this shortly. Mark [1] http://people.apache.org/~markt/presentations/2010-11-04-Memory-Leaks-60mins.pdf > > -bob > > -----Original Message----- From: Mark Thomas > [mailto:ma...@apache.org] Sent: Friday, October 21, 2011 7:42 AM To: > Tomcat Users List Subject: Re: JAR locked in Tomcat after using > addUrl to dynamically add JAR to running webapp > > On 21/10/2011 12:22, Bob DeRemer wrote: >> Hi Mark, >> >> With regard to using Tomcat in production, that was meant >> sarcastically - the team has done a nice job on later Tomcat 6 and >> Tomcat 7 32/64-bit installations - including Windows Service >> support, etc. - nice work. > > That comment was more aimed at the archives than you ;) > >> With regard to using YourKit, I have a licensed copy, but must be >> missing something - where can I look to see what is holding a >> reference to the JAR? I've used it for memory analysis and CPU >> profiling - primarily, but I'm not sure where to look for JAR >> references. > > File locks can be tricky to pin down. I usually do something along > the lines of: 1. Take a memory snapshot 2. Switch to the object view > 3. Search for the name of the JAR 4. Trace the GC roots of a > promising looking object > > Normally, the JAR name appears in a String for a JarFile or File > object and that traces back to whatever is holding the reference. > > I'd be happy to take a look at the snapshot for you if you can put > the snapshot somewhere where I can download it. > > Mark > > >> >> Thanks, Bob >> >> -----Original Message----- From: Mark Thomas >> [mailto:ma...@apache.org] Sent: Friday, October 21, 2011 2:46 AM >> To: Tomcat Users List Subject: Re: JAR locked in Tomcat after using >> addUrl to dynamically add JAR to running webapp >> >> On 21/10/2011 03:00, Bob DeRemer wrote: >>> While I can appreciate the desire to never use Windows, that >>> isn't reality in many of the industries that use our product, so >>> running Tomcat on windows can't be considered an oddity or edge >>> case. If it is, we better look for another app server. >> >> If that were the case, the Tomcat devs wouldn't have put the >> investment they have into the Windows installer in recent months >> (auto detection of 32 or 64 bit JRE, greater control over ports, >> multiple service installs of the same version, ...) >> >>> With regard to finding a solution, I'll try the antiJarLocking >>> setting, but I don't have any problem with any other JARS, so I >>> don't hold out much hope for this fixing my problem. I may look >>> at upgrading to JDK 7 - which has added a "close" method to the >>> URLClassLoader. Perhaps this might fix it. >> >> Maybe. >> >>> If anyone else has any other ideas why ONLY JARs added via the >>> addURL "hack" I've shown below don't get unloaded when the WEBAPP >>> is shutdown - vs stopping Tomcat completely, I would greatly >>> appreciate it. >> >> You need to understand the root cause. I'd recommend getting a >> profiler (I use YourKit since they give free copies to Tomcat >> committers) and finding out exactly what is holding references to >> those JARs. Once you know that the next questions are 1. What >> creates those references and 2. How to get rid of them. >> >> Mark >> >> --------------------------------------------------------------------- >> >> > >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >> For additional commands, e-mail: users-h...@tomcat.apache.org >> >> >> --------------------------------------------------------------------- >> >> > >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >> For additional commands, e-mail: users-h...@tomcat.apache.org >> > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
