Re: Immortal sessions in production
Re: Immortal sessions in production
- Subject: Re: Immortal sessions in production
- From: Matteo Centro <email@hidden>
- Date: Sun, 13 Jan 2013 10:40:52 +0100
It's a mess... There are ECs created in some DirectActions, and ECs
created in methods in Application but all the edit operations happen
in the Session EC. All ECs are ERXECs and no explicit locks happen.
Should I explicitly lock the session EC in the terminate method?
Matteo
On Sun, Jan 13, 2013 at 10:36 AM, Amedeo Mantica <email@hidden> wrote:
> Are you sure the ec is only referenced by the session? Maybe there are objects referencing it outside the session. Application ? Any shared object ? A thread ?
>
> Amedeo
>
> Sent from my iPhone
>
> On 12/gen/2013, at 23:01, Matteo Centro <email@hidden> wrote:
>
>> Thanks, I'll try that.
>> Anyway (I can't say it's that but this happens often in instances with
>> immortal sessions):
>> I get this in my terminate() method
>> java.lang.IllegalMonitorStateException
>> at java.util.concurrent.locks.ReentrantLock$Sync.tryRelease(ReentrantLock.java:127)
>> at java.util.concurrent.locks.AbstractQueuedSynchronizer.release(AbstractQueuedSynchronizer.java:1239)
>> at java.util.concurrent.locks.ReentrantLock.unlock(ReentrantLock.java:431)
>> at com.webobjects.eocontrol.EOObjectStoreCoordinator.unlock(EOObjectStoreCoordinator.java:460)
>> at com.webobjects.eocontrol.EOEditingContext.unlockObjectStore(EOEditingContext.java:4684)
>> at er.extensions.eof.ERXEC.unlockObjectStore(ERXEC.java:805)
>> at com.webobjects.eocontrol.EOCustomObject.willReadRelationship(EOCustomObject.java:1281)
>> at er.extensions.eof.ERXGenericRecord.willReadRelationship(ERXGenericRecord.java:378)
>> at com.webobjects.eocontrol._EOMutableKnownKeyDictionary$Initializer$_LazyGenericRecordBinding.valueInObject(_EOMutableKnownKeyDictionary.java:614)
>> at com.webobjects.eocontrol.EOCustomObject.storedValueForKey(EOCustomObject.java:1634)
>>
>> I'm using ERXEC everywhere and I'm not locking explicitly, should I
>> lock the ec in the terminate method?
>>
>>
>> Matteo
>>
>> On Sat, Jan 12, 2013 at 8:39 PM, Simon <email@hidden> wrote:
>>> stick this in your session constructor, it will log out whenever a
>>> session is created. then you can start figuring out where you are
>>> creating a session outside the RR loop which is the normal culprit...
>>>
>>> StringWriter stringWriter = new StringWriter();
>>> PrintWriter printWriter = new PrintWriter(stringWriter);
>>> (new Throwable()).printStackTrace(printWriter);
>>> String trace = stringWriter.toString();
>>> log.debug("Session count = " + application().activeSessionsCount());
>>> ClickEventLogger2.getLogger().fatal(ClickEventCode.E00129, "Session
>>> Created:\n\n " + trace,
>>> this.getClass().getSimpleName());
>>>
>>> hmmm, you'll have to replace the "ClickEventLogger2" line because
>>> that's our logging mechanism. you could log.fatal it and set up an
>>> email appender in log4j.
>>>
>>> simon
>>>
>>>
>>> On 12 January 2013 17:43, Matteo Centro <email@hidden> wrote:
>>>> Sorry to resuscitate such an old discussion but I'm having the exact
>>>> same issue...
>>>> It's an old application that we "inherited", we wonderized it as much
>>>> as it's possible but something weird happens in production, sessions
>>>> on some instances simply won't die.
>>>> Some instances go out of memory and they hang there.
>>>> I'm in trouble and I needs some hints, both to fix the issue
>>>> temporarily and to fix it for good (of course in that case I assume
>>>> I'll have to rewrite the app, if only I could find the budget).
>>>> What are the most common causes of sessions not dying?
>>>>
>>>> Thanks,
>>>>
>>>>
>>>> Matteo
>>>>
>>>> On Thu, Aug 21, 2008 at 5:35 AM, Joe Little <email@hidden> wrote:
>>>>> I had something similar with sessions going bonkers on a public WO
>>>>> page that our internal google search engine completely trashed. In the
>>>>> end, robots.txt and explicit rules to deny certain patterns were added
>>>>> to prevent this.
>>>>>
>>>>>
>>>>> On Wed, Aug 20, 2008 at 8:17 PM, D Tim Cummings <email@hidden> wrote:
>>>>>> We have a couple of sessionless apps that have started showing this problem
>>>>>> with sessions that don't terminate. It turned out the sessions were being
>>>>>> created by malformed urls coming from malicious robot web crawlers. The
>>>>>> urls were of the form
>>>>>> http://www.courses.qut.edu.au/cgi-bin/WebObjects/Courses.woa/wa/cgi-bin/WebObjects/Courses.woa
>>>>>> Maybe see if you are getting incorrect links to your sessionless login page.
>>>>>> We solved the problem by catching unknown direct actions in
>>>>>> DirectAction.java
>>>>>> @Override
>>>>>> public WOActionResults performActionNamed(String actionName) {
>>>>>> try {
>>>>>> return super.performActionNamed(actionName);
>>>>>> } catch (NSForwardException nsfe) {
>>>>>> log.info("ns forward exception - prbalby no such method for " + actionName);
>>>>>> }
>>>>>> return defaultAction();
>>>>>> }
>>>>>> and in Application.java directing exceptions back to the Main page (for URLs
>>>>>> with more than one / after wa).
>>>>>> @Override
>>>>>> public WOComponent pageWithName(String namePage, WOContext context) {
>>>>>> if ( "WOExceptionPage".equals(namePage) ) {
>>>>>> namePage = "Main";
>>>>>> }
>>>>>> if ( "WOSessionRestorationError".equals(namePage) ) {
>>>>>> namePage = "Main";
>>>>>> }
>>>>>> return super.pageWithName(namePage, context);
>>>>>> }
>>>>>>
>>>>>> and in Main.java
>>>>>> public void setException ( Exception e ) {
>>>>>> log.error("an exception occurred " + e);
>>>>>> }
>>>>>>
>>>>>> We are running apps with embedded Wonder 4 and WebObjects 5.3.3 on Mac OS X
>>>>>> Server 10.5.4 with WebObjects 5.4.2 deployment. We didn't have the problem
>>>>>> before we went to this setup, but maybe we weren't getting hit with the same
>>>>>> url format then.
>>>>>> Tim
>>>>>> On 21/08/2008, at 4:02 AM, Chuck Hill wrote:
>>>>>>
>>>>>> On Aug 20, 2008, at 9:54 AM, Simon McLean wrote:
>>>>>>
>>>>>> Hi All -
>>>>>> Wondering if someone can throw me some ideas on solving what looks like an
>>>>>> immortal session problem.
>>>>>> - Start up 1 instance in java monitor.
>>>>>> - User lands on sessionless login page. No sessions.
>>>>>> - User logs in. 1 session.
>>>>>> - User logs out. 0 sessions.
>>>>>> - User logs in. 1 session.
>>>>>> - User does nothing. Session times out. 0 sessions.
>>>>>> All looks good. However, we get to the end of the day and the instance has
>>>>>> 376 active sessions. But I know for this particular app there are only 6
>>>>>> users, because they are all sitting next door :-) Also, If i now leave this
>>>>>> instance overnight none of those active sessions will go away.
>>>>>> So what could be going on ? Something appears to be creating immortal
>>>>>> sessions, but forced session termination (by the user logging out) and
>>>>>> session expiration seem to be behaving themselves.
>>>>>>
>>>>>> If the users don't notice any problems, my money would be on an exception
>>>>>> thrown from your Session.terminate(). Also check the sleep() method to
>>>>>> ensure it can never throw.
>>>>>> I have seen a related problem where two requests come in for the same
>>>>>> session (user double clicks, Ajax etc), and the first calls terminate() on
>>>>>> the session. The second thread is stuck and the app can't gracefully shut
>>>>>> down. IIRC, you would see zero sessions in this case. The "fix" for this
>>>>>> is to not call terminate() and instead set the session timeout to a small
>>>>>> number of seconds.
>>>>>> Chuck
>>>>>> --
>>>>>> 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/products/practical_webobjects
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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