activemq-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Hiram Chirino (JIRA)" <j...@apache.org>
Subject [jira] Commented: (AMQ-1490) Deadlocks (with JUnit tests)
Date Tue, 13 Nov 2007 22:12:27 GMT

    [ https://issues.apache.org/activemq/browse/AMQ-1490?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_40601
] 

Hiram Chirino commented on AMQ-1490:
------------------------------------

I reviewed you test case and noticed that your consumer uses the same connection as the producer.
 It is possible to get into a deadlock situation when this occurs.  If your producer blocks
due to it waiting space on the broker, it will lock up the connection.  At that point the
consumer will not be able to consume anymore messages either.

I believe your deadlocks will go away if you use separate connections for the consumer and
producer threads.

> Deadlocks (with JUnit tests)
> ----------------------------
>
>                 Key: AMQ-1490
>                 URL: https://issues.apache.org/activemq/browse/AMQ-1490
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: Broker
>    Affects Versions: 5.0.0
>         Environment: Linux
>            Reporter: Rainer Klute
>             Fix For: 5.0.0
>
>         Attachments: ActiveMQ_Testcases.jar
>
>
> For some time now there have been various bug reports about ActiveMQ "blocking", "not
receiving messages", "running into a deadlock" etc. Since I encoutered such deadlocks now
and then, too, I eventually wrote up a JUnit testing scenario for this stuff. I found out
that deadlocks can be quite easily reproduced. The symptoms are that the producer thread is
sending or committing while the consumer thread is receiving or committing - and none of them
can advance. One of the threads is always stuck in a blocking queue.
> Here's a sample output of my testing class:
>  An ActiveMQ deadlock has been discovered. The following threads seem to be involved:
>  Thread "producer" is inactive since 16 seconds after 358719 status changes. The current
status is COMMITTING
>  sun.misc.Unsafe.park(Native Method)
>  java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
>   java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1889)
>  java.util.concurrent.ArrayBlockingQueue.take(ArrayBlockingQueue.java:317)
>  org.apache.activemq.transport.FutureResponse.getResult(FutureResponse.java:40)
>  org.apache.activemq.transport.ResponseCorrelator.request(ResponseCorrelator.java:76)
>  org.apache.activemq.ActiveMQConnection.syncSendPacket(ActiveMQConnection.java:1172)
>  org.apache.activemq.TransactionContext.commit(TransactionContext.java:259)
>  org.apache.activemq.ActiveMQSession.commit(ActiveMQSession.java:494)
>  de.rainer_klute.activemq.ProducerThread.run(ProducerThread.java:162)
>  Thread "consumer" is inactive since 16 seconds after 1807 status changes. The current
status is RECEIVING
>  java.lang.Object.wait(Native Method)
>  java.lang.Object.wait(Object.java:485)
>  org.apache.activemq.MessageDispatchChannel.dequeue(MessageDispatchChannel.java:75)
>  org.apache.activemq.ActiveMQMessageConsumer.dequeue(ActiveMQMessageConsumer.java:404)
>  org.apache.activemq.ActiveMQMessageConsumer.receive(ActiveMQMessageConsumer.java:452)
>  org.apache.activemq.ActiveMQMessageConsumer.receive(ActiveMQMessageConsumer.java:504)
>  de.rainer_klute.activemq.ConsumerThread.run(ConsumerThread.java:183)
> The following factors seem to increase the probability of a deadlock:
> * small values for memoryUsage
> * working transacted in the consumer (not always necessary but "helps")
> * many messages in the persistence store (to be achieved via a long delay before the
consumer starts to read messages)

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message