3 messages in org.apache.jackrabbit.usersAW: dangling connections on JBoss
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Foo BarOct 12, 2007 6:22 pm 
Norbert DreisiebnerOct 15, 2007 2:43 am 
Foo BarOct 15, 2007 6:34 am 
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Subject:AW: dangling connections on JBossActions...
From:Norbert Dreisiebner (norb@hms.org)
Date:Oct 15, 2007 2:43:33 am
List:org.apache.jackrabbit.users

Hi Alexander!

I also experienced the same problems like you using the jackrabbit jca
connector.

When using jackrabbit 1.3.1 there is a workaround regarding the first issue: add
<track-connection-by-tx/> to your jackrabbit ds. That should make your
transactions work without REQUIRES_NEW.

The by far better solution imho is to upgrade to jackrabbit 1.3.3 where this bug
(JCR-1109) seems to be resolved.

Moving on to the second problem I think that you have to logout from your
sessions manually. Currently I do this the following way:

public someMethod() {

// aquire your jcr session here Session session = .....

try {

// do your business stuff....

} finally {

session.logout(); } }

Doing so, you won't run out of transaction connections.

That's the way things are running now... but I just cannot believe that that's
the best approach. Isn't the creation of a jcr session object within each method
call a huge performance overhead?

Using jackrabbit 1.3.3 the session object now also works as simple member
variable that is instantiated at bean construction - but only if I set property
"bindSessionToTransaction" in jackrabbit ds to false, otherwise I get a
"Inactive logical session handle called" exception.

The problem is that in this case the transaction handling doesn't work as
expected... (e.g. data is stored even if transaction is set to roll back) so it
seems that there's no way around instantiating the session object within every
single method call..... any ideas? :)

Best regards Norbert D

-----Ursprüngliche Nachricht----- Von: Foo Bar [mailto:mitt@gmail.com] Gesendet: Samstag, 13. Oktober 2007 03:23 An: use@jackrabbit.apache.org Betreff: dangling connections on JBoss

Hi!

I'm using JBoss 4.2.1GA and jackrabbit 1.3.1, with JCA connector 1.3.1. My config is as follows:

<pre> <tx-connection-factory> <jndi-name>jcr/local</jndi-name> <xa-transaction/> <rar-name>convertfrontend-1.0-SNAPSHOT.ear#jackrabbit-jca.rar</rar-name> <connection-definition>javax.jcr.Repository</connection-definition> <config-property name="homeDir" type="java.lang.String">/var/mediastorage/jcrstore</config-property> <config-property name="configFile" type="java.lang.String">classpath:repository.xml</config-property> <config-property name="bindSessionToTransaction" type="java.lang.Boolean">true</config-property> </tx-connection-factory> </pre>

My first issue was that I was experiencing the two-sessions per transaction deadlock, for no apparent reason (used one transaction and one session). This made me to use REQUIRES_NEW transaction attributes on all jackrabbit save operations, which surprisingly helped getting rid of the deadlock. Anyway, now that I've done that, it still seems like jackrabbit is not really logging out sessions, since I run out of transaction connections after exactly 20 fetches (reproducable):

<pre> java.lang.RuntimeException: Error initializing JCR access:javax.jcr.RepositoryException: No ManagedConnections available within configured blocking timeout ( 30000 [ms] ): No ManagedConnections available within configured blocking timeout ( 30000 [ms] ) </pre>

I also get some warnings before this happens:

<pre> [org.jboss.resource.connectionmanager.CachedConnectionManager] Could not find a close method on alleged connection objects. Please close your own connections. </pre>

I have an alternative storage implementation using java.io, and I have no such problems when I switch to that solution, so I beleive that the problem is from within jackrabbit.

My theory is that the sessions never get commited. The first workaround with the double sessions convinced me, since I was calling different session beans from a server, with no more than one jcr session in each method call. The fact that the multiple session bug was visible in this situation should indicate that the session must survive the transaction and still be attached to the current thread even after the transaction has ended.

This theory also seems logical with respect to the fact that everything started to work after REQUIRES_NEW, but that I ran out of threads.

Is there anything that I have missed to do in order to be sure that sessions get closed at the end of each transaction? Do I need to do a session logout programmatically? Does anyone have any suggestion as to what I should do to make this work? Any help is greatly appriciated.

I've searched the mailing list, and found a couple of similar issues, with no answers:
http://article.gmane.org/gmane.comp.apache.jackrabbit.user/979/match=blocking+timeout
http://article.gmane.org/gmane.comp.apache.jackrabbit.user/637/match=blocking+timeout

Best Regards

/Alexander T

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