Re: MDC does not properly clean up
On 24.09.10 17:04, Jacob Kjome wrote: Since Log4j must support JDK1.4 (actually, still 1.3, I believe), I don't see how we could use JDK1.5+ ThreadLocal.remove()? That said, there are other ways of cleaning up ThreadLocals that don't require remove(). For examples, see CrazyBob's "Hard Core Java: ThreadLocal" from back in 2006 [1]. Log4j could utilize CrazyBob's suggestions and provide an MDC cleanup method to allow users a chance to clean up. Thoughts? logback apparently had the same issue. It was fixed a few hours ago: http://jira.qos.ch/browse/LBCLASSIC-183 Also, for reference, I thought I'd provide a link to what the commons-lang guys did to fix their memory leaks, though keep in mind it depends on the JDK1.5+ ThreadLocal.remove() method [2]. They also use a WeakHashMap, which I'm not sure is necessary or not for Log4j's purposes? [1] http://blog.crazybob.org/2006/07/hard-core-java-threadlocal.html [2] https://fisheye6.atlassian.com/browse/commons/proper/lang/trunk/src/main/java/org/apache/commons/lang3/builder/ToStringStyle.java#r907126 Jake On Fri, 24 Sep 2010 09:24:10 +0200 Marcel Stör wrote: The initial problem description was sent to the users list: http://www.mail-archive.com/log4j-u...@logging.apache.org/msg11921.html However, I think it actually belongs here... I believe that the MDC should provide a method that internally calls ThreadLocal#remove which was added to the API with Java5: http://download.oracle.com/javase/6/docs/api/java/lang/ThreadLocal.html#remove%28%29 Other libraries/frameworks start fixing their issues with this, too: - https://issues.apache.org/jira/browse/LANG-586 - https://jira.springsource.org/browse/SPR-7441 - https://jira.springsource.org/browse/SEC-1578 -- Marcel Stör, http://www.frightanic.com Couchsurfing: http://www.couchsurfing.com/people/marcelstoer O< ascii ribbon campaign - stop html mail - www.asciiribbon.org - To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org For additional commands, e-mail: log4j-dev-h...@logging.apache.org
Re: MDC does not properly clean up
On 24.09.2010, at 17:04, Jacob Kjome wrote: > Since Log4j must support JDK1.4 (actually, still 1.3, I believe), I don't see > how we could use JDK1.5+ ThreadLocal.remove()? I suspected something like this...I was actually surprised to see that there's still development activity here. What I see sometimes with other libraries which have similar constraints is that they detect JVM versions and act accordingly (in some cases issuing commands via reflection). > That said, there are other ways of cleaning up ThreadLocals that don't > require remove(). For examples, see CrazyBob's "Hard Core Java: ThreadLocal" > from back in 2006 [1]. Log4j could utilize CrazyBob's suggestions and > provide an MDC cleanup method to allow users a chance to clean up. Thoughts? From a client application developer's point of view there should be "some means" to clear this that works reliably on somewhat modern JVMs. Please note that - Tomcat only runs its clean-up operations when it runs on Sun JVMs - only Sun JVMs seem to have that memory issue because they load classes into permgen - not clearing MDC ThreadLocal only becomes an issue when frequently hot-deploying an application in a container (something you don't wanna do in production environments anyway) As a client application developer I care because customers are breathing down our neck to get this fixed nonetheless. Marcel -- Marcel Stör, http://www.frightanic.com Couchsurfing: http://www.couchsurfing.com/people/marcelstoer O< ascii ribbon campaign - stop html mail - www.asciiribbon.org - To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org For additional commands, e-mail: log4j-dev-h...@logging.apache.org
Re: MDC does not properly clean up
Since Log4j must support JDK1.4 (actually, still 1.3, I believe), I don't see how we could use JDK1.5+ ThreadLocal.remove()? That said, there are other ways of cleaning up ThreadLocals that don't require remove(). For examples, see CrazyBob's "Hard Core Java: ThreadLocal" from back in 2006 [1]. Log4j could utilize CrazyBob's suggestions and provide an MDC cleanup method to allow users a chance to clean up. Thoughts? Also, for reference, I thought I'd provide a link to what the commons-lang guys did to fix their memory leaks, though keep in mind it depends on the JDK1.5+ ThreadLocal.remove() method [2]. They also use a WeakHashMap, which I'm not sure is necessary or not for Log4j's purposes? [1] http://blog.crazybob.org/2006/07/hard-core-java-threadlocal.html [2] https://fisheye6.atlassian.com/browse/commons/proper/lang/trunk/src/main/java/org/apache/commons/lang3/builder/ToStringStyle.java#r907126 Jake On Fri, 24 Sep 2010 09:24:10 +0200 Marcel Stör wrote: The initial problem description was sent to the users list: http://www.mail-archive.com/log4j-u...@logging.apache.org/msg11921.html However, I think it actually belongs here... I believe that the MDC should provide a method that internally calls ThreadLocal#remove which was added to the API with Java5: http://download.oracle.com/javase/6/docs/api/java/lang/ThreadLocal.html#remove%28%29 Other libraries/frameworks start fixing their issues with this, too: - https://issues.apache.org/jira/browse/LANG-586 - https://jira.springsource.org/browse/SPR-7441 - https://jira.springsource.org/browse/SEC-1578 Regards, Marcel P.S. I'm using the slf4j MDC but AFAIK it simply delegates to log4j. -- Marcel Stör, http://www.frightanic.com Couchsurfing: http://www.couchsurfing.com/people/marcelstoer O< ascii ribbon campaign - stop html mail - www.asciiribbon.org - To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org For additional commands, e-mail: log4j-dev-h...@logging.apache.org - To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org For additional commands, e-mail: log4j-dev-h...@logging.apache.org
MDC does not properly clean up
The initial problem description was sent to the users list: http://www.mail-archive.com/log4j-u...@logging.apache.org/msg11921.html However, I think it actually belongs here... I believe that the MDC should provide a method that internally calls ThreadLocal#remove which was added to the API with Java5: http://download.oracle.com/javase/6/docs/api/java/lang/ThreadLocal.html#remove%28%29 Other libraries/frameworks start fixing their issues with this, too: - https://issues.apache.org/jira/browse/LANG-586 - https://jira.springsource.org/browse/SPR-7441 - https://jira.springsource.org/browse/SEC-1578 Regards, Marcel P.S. I'm using the slf4j MDC but AFAIK it simply delegates to log4j. -- Marcel Stör, http://www.frightanic.com Couchsurfing: http://www.couchsurfing.com/people/marcelstoer O< ascii ribbon campaign - stop html mail - www.asciiribbon.org - To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org For additional commands, e-mail: log4j-dev-h...@logging.apache.org
