Hi Chuck, a follow-up on this:
Am 19.10.2012 um 20:05 schrieb Chuck Hill <ch...@global-village.net>: > Hi Maik, > > This can also indicate some other things too: > - session did not get checked in (app threw OutOfMemory, sleep() threw an > exception) > - previous request for this session is still running (deadlock, waiting, > infinite loop) > - 2+ requests for the same session in rapid sequence where the first > terminates the session Looks like my answer that OutOfMemory would be "OutOfTheQuestion" was not true. I now discovered what lead to my application hanging every afternoon, after *once* it finally cared to log a proper message before hanging: java.util.concurrent.ExecutionException: java.lang.OutOfMemoryError: PermGen space Doh, the PermGen. I totally forgot about that. I had the app at -Xmx24576m, but didn't adjust PermGen. Now with a PermGen limit of 512m (of which currently about 154m gets used max according to jvisualvm) everything is finally running smoothly. The app turns out to load about 12000 classes over a workday. I think I need to have a look at what those are sometime... Maik > > > Chuck > > > > On 2012-10-19, at 4:00 AM, Maik Musall wrote: > >> Hi, >> >> I recently discovered what may be responsible for frequent deadlocks of an >> application here. In the "jstack -l" output, I see almost all threads >> waiting on a single ReentrantLock, and this thread is what holds that lock: >> >> >> "WorkerThread4" prio=5 tid=103bc9000 nid=0x132caf000 in Object.wait() >> [132cae000] >> java.lang.Thread.State: WAITING (on object monitor) >> at java.lang.Object.wait(Native Method) >> - waiting on <22711d098> (a >> com.webobjects.appserver.WOSessionStore$TimeoutEntry) >> at java.lang.Object.wait(Object.java:485) >> at >> com.webobjects.appserver.WOSessionStore.checkOutSessionWithID(WOSessionStore.java:191) >> - locked <22711d098> (a >> com.webobjects.appserver.WOSessionStore$TimeoutEntry) >> at >> com.webobjects.appserver.WOApplication.restoreSessionWithID(WOApplication.java:1913) >> at >> er.extensions.appserver.ERXApplication.restoreSessionWithID(ERXApplication.java:2440) >> at >> er.extensions.appserver.ERXComponentRequestHandler._dispatchWithPreparedApplication(ERXComponentRequestHandler.java:260) >> at >> er.extensions.appserver.ERXComponentRequestHandler._handleRequest(ERXComponentRequestHandler.java:302) >> at >> er.extensions.appserver.ERXComponentRequestHandler.handleRequest(ERXComponentRequestHandler.java:377) >> at >> com.webobjects.appserver.WOApplication.dispatchRequest(WOApplication.java:1687) >> at >> er.extensions.appserver.ERXApplication.dispatchRequestImmediately(ERXApplication.java:2139) >> at >> er.extensions.appserver.ERXApplication.dispatchRequest(ERXApplication.java:2104) >> at >> com.webobjects.appserver._private.WOWorkerThread.runOnce(WOWorkerThread.java:144) >> at >> com.webobjects.appserver._private.WOWorkerThread.run(WOWorkerThread.java:226) >> at java.lang.Thread.run(Thread.java:680) >> >> Locked ownable synchronizers: >> - <20ce7bbc0> (a java.util.concurrent.locks.ReentrantLock$NonfairSync) >> >> >> Now, ERXApplication.restoreSessionWithID contains an interesting call to >> useSessionStoreDeadlockDetection(), but this detection only works in single >> threaded mode. I'm afraid I can't afford to switch off concurrent requests >> even for a testing period in production. >> >> I'm looking for someone with experience regarding this problem. The doc for >> that method mentions that it could help "to find cases when a session is >> checked out twice in a single RR-loop, which will lead to a session store >> lockup." Since I cannot switch on this detection, what in your experience >> could lead to that happening? >> >> Thanks >> Maik >> _______________________________________________ >> Do not post admin requests to the list. They will be ignored. >> Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) >> Help/Unsubscribe/Update your Subscription: >> https://lists.apple.com/mailman/options/webobjects-dev/chill%40global-village.net >> >> This email sent to ch...@global-village.net > > -- > Chuck Hill Senior Consultant / VP Development > > Practical WebObjects - for developers who want to increase their overall > knowledge of WebObjects or who are trying to solve specific problems. > http://www.global-village.net/gvc/practical_webobjects > > Global Village Consulting ranks 13th in 2012 in BIV's Top 100 Fastest Growing > Companies in B.C! > Global Village Consulting ranks 76th in 24th annual PROFIT 200 ranking of > Canada’s Fastest-Growing Companies by PROFIT Magazine! > > > > > > > > _______________________________________________ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
