Re: Potential reuse of TagHandlers implementing JspIdConsumer?
Hi, I finally found the time to build a test case for this issue. I attach the WAR, but you still need to put the runtime library of AspectJ (aspectjrt.jar) on the classpath when running Tomcat. The behavior I observe is that whenever I load/reload the page, the JspIdConsumer objects get allocated, and some, but never all of them get GC'd. You should see messages on the console/log like Adding JspIdConsumer:someClassName:itsHashCode:theJspId and Removed someJspId You will see three Adding messages for every instance created (it's a mess to track this properly), and you should see one Removed message for every GC'd instance. When I run grep | wc on the output, the distance between the number of created and GC'd object grows over time and reloads of the test page. I had this running for a bit, trying to see if after a session timeout the remaining instances would be GC'd, but they didn't. I don't know what to make of this, but it feels like Tomcat is holding on to some of the instances for too long for no good reason. Jochen - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: Potential reuse of TagHandlers implementing JspIdConsumer?
Jochen Wuttke wrote: Hi, I finally found the time to build a test case for this issue. I attach the WAR, The users list won't accept attachments. You;ll need to open a bugzilla entry and attach your test case there. Mark but you still need to put the runtime library of AspectJ (aspectjrt.jar) on the classpath when running Tomcat. The behavior I observe is that whenever I load/reload the page, the JspIdConsumer objects get allocated, and some, but never all of them get GC'd. You should see messages on the console/log like Adding JspIdConsumer:someClassName:itsHashCode:theJspId and Removed someJspId You will see three Adding messages for every instance created (it's a mess to track this properly), and you should see one Removed message for every GC'd instance. When I run grep | wc on the output, the distance between the number of created and GC'd object grows over time and reloads of the test page. I had this running for a bit, trying to see if after a session timeout the remaining instances would be GC'd, but they didn't. I don't know what to make of this, but it feels like Tomcat is holding on to some of the instances for too long for no good reason. Jochen - 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
Re: Potential reuse of TagHandlers implementing JspIdConsumer?
Hi, I'd like to bump this issue once more. I finally had some time to run some more experiments to see what happens with TagHandlers that implement JspIdConsumer. My setup is Tomcat 6 + MyFaces + JSF CarDemo, and I'm using AspectJ to trace creation and garbage collection of objects implementing JspIdConsumer. My experiments indicate the following: 1. JspIdConsumer instances do NOT get garbage collected after a page has finished processing. 2. JspIdConsumer instances do NOT get garbage collected after a session times out. 3. SOME JspIdConsumer instances DO get garbage collected when a given JSP-generated page is reloaded or accessed in a different session. To obtain these results I ran Tomcat with very little heap memory (it seems it starts fine with the 64M default), loaded the car demo in several browser sessions and ran through all the other JSP/Servlet examples that come with Tomcat to increase the memory consumption and trigger GC. Unfortunately I don't have the time and tools to do a proper stress test. In any case, considering the specification of JspIdConsumer, which states that instances may never be reused, the caching of these instances as it is done in current JSPs is unnecessary, and since these instances don't seem to be GC'd, this seems to be a memory leak. Could the developers confirm this or suggest what is going on that I'm missing? Jochen Wuttke --- PhD Candidate Faculty of Informatics University of Lugano Via Giuseppe Buffi 13 CH-6904 Lugano - Switzerland phone: +41 58 666 4308 www.inf.unisi.ch/phd/wuttke - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Potential reuse of TagHandlers implementing JspIdConsumer?
Jochen Wuttke wrote: Hi, I'd like to bump this issue once more. I finally had some time to run some more experiments to see what happens with TagHandlers that implement JspIdConsumer. My setup is Tomcat 6 + MyFaces + JSF CarDemo, and I'm using AspectJ to trace creation and garbage collection of objects implementing JspIdConsumer. My experiments indicate the following: 1. JspIdConsumer instances do NOT get garbage collected after a page has finished processing. 2. JspIdConsumer instances do NOT get garbage collected after a session times out. 3. SOME JspIdConsumer instances DO get garbage collected when a given JSP-generated page is reloaded or accessed in a different session. To obtain these results I ran Tomcat with very little heap memory (it seems it starts fine with the 64M default), loaded the car demo in several browser sessions and ran through all the other JSP/Servlet examples that come with Tomcat to increase the memory consumption and trigger GC. Unfortunately I don't have the time and tools to do a proper stress test. In any case, considering the specification of JspIdConsumer, which states that instances may never be reused, the caching of these instances as it is done in current JSPs is unnecessary, and since these instances don't seem to be GC'd, this seems to be a memory leak. Could the developers confirm this or suggest what is going on that I'm missing? 3 looks like a possible memory leak although I can't be certain with the information provided here. A simple test case (that doesn't use JSF) would help. 1 2 could just be poor recycling rather than a leak. Again, a test case would help clarify this. Mark - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Potential reuse of TagHandlers implementing JspIdConsumer?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Jochen, I'd definitely like to know the answer to this, too. Replying to bump the topic. - -chris Jochen Wuttke wrote: Hi, for my research project I've been doing some ApsectJ magic with Tomcat and deployed WebApps. Among other things I'm interested in detecting at runtime when TagHandlers instantiated in a HttpServlet go out of scope. Since that can't be done with AspectJ I was tracking garbage collection to see when the objects get removed. To be sure that that made some sense I looked at where the servlet code instantiates the TagHandlers, and since they are created and used as local variables, I was expecting them to be collected after the servlet finishes processing. Unfortunately, a few experiments showed that that is not the case. After delving into the details of the servlet code generated for JSP pages I discovered that the methods instantiating TagHandlers also store them in TagHandlerPools using #reuse(). I'm doing my experiments with a demo application for Java Server Faces, and all JSF tag handler implement javax.servlet.jsp.tagext.JspIdConsumer. The spec says that handler implementing that interface may not be reused, so I was wondering if this is a potential bug or if I'm missing some intricate detail of how things work. Thanks, Jochen - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkj8ivkACgkQ9CaO5/Lv0PBVxgCeMV3deLI4A+CtT+WY26+DLV3/ K7IAnR0nNeb29DYPoTf6V6M88HVeeojm =rlNa -END PGP SIGNATURE- - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Potential reuse of TagHandlers implementing JspIdConsumer?
Hi, for my research project I've been doing some ApsectJ magic with Tomcat and deployed WebApps. Among other things I'm interested in detecting at runtime when TagHandlers instantiated in a HttpServlet go out of scope. Since that can't be done with AspectJ I was tracking garbage collection to see when the objects get removed. To be sure that that made some sense I looked at where the servlet code instantiates the TagHandlers, and since they are created and used as local variables, I was expecting them to be collected after the servlet finishes processing. Unfortunately, a few experiments showed that that is not the case. After delving into the details of the servlet code generated for JSP pages I discovered that the methods instantiating TagHandlers also store them in TagHandlerPools using #reuse(). I'm doing my experiments with a demo application for Java Server Faces, and all JSF tag handler implement javax.servlet.jsp.tagext.JspIdConsumer. The spec says that handler implementing that interface may not be reused, so I was wondering if this is a potential bug or if I'm missing some intricate detail of how things work. Thanks, Jochen - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
