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Date: Thu, 9 Apr 2015 21:55:12 +0000 (UTC)
From: "Timothy Bish (JIRA)" <jira@apache.org>
To: dev@activemq.apache.org
Message-ID: <JIRA.12819015.1428431504000.46371.1428616512495@Atlassian.JIRA>
In-Reply-To: <JIRA.12819015.1428431504000@Atlassian.JIRA>
References: <JIRA.12819015.1428431504000@Atlassian.JIRA>
 <JIRA.12819015.1428431504053@arcas>
Subject: [jira] [Commented] (AMQ-5712) Broker can deadlock when using queues
 while producers wait on disk space
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    [ https://issues.apache.org/jira/browse/AMQ-5712?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14488355#comment-14488355 ] 

Timothy Bish commented on AMQ-5712:
-----------------------------------

I believe I've run into this while doing some testing for AMQP flow control issues.  Once I did some debugging I remembered this issue while looking into the stack traces.  

> Broker can deadlock when using queues while producers wait on disk space
> ------------------------------------------------------------------------
>
>                 Key: AMQ-5712
>                 URL: https://issues.apache.org/jira/browse/AMQ-5712
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: Broker
>    Affects Versions: 5.11.1
>            Reporter: Christopher L. Shannon
>
> I am experiencing a deadlock when using a Queue with non-persistent messages.  The queue has a cursor high memory water mark set (right now at 70%).  When a producer is producing messages quickly to the queue and that limit gets hit, the broker can deadlock.   I have tried setting producerWindowSize and alwaysSyncSend which did not seem to help. When the broker hits that limit, I am unable to do things like purge the queue.  Consumers can also deadlock as well. 
> Note that this appears to be the same issue as described in this ticket here: AMQ-2475 .  The difference is that I am using a Queue and not a Topic and the fix for this appears to only have been for Topics.
> The problem appears to be in the Queue class on line 1852 inside the {{cursorAdd}} method.  The method being called is {{return messages.addMessageLast(msg);}} which will block indefinitely if there is no space available, which in turn ties up the {{messagesLock}} from being used by any other threads.  We have seen a deadlock where consumers can't consume because they are waiting on this lock.   It looks like in AMQ-2475 part of the fix was to replace {{messages.addMessageLast(msg)}} with {{messages.tryAddMessageLast(msg, 10)}}.  I also noticed that not all of the message cursors support {{tryAddMessageLast}}, which could be a problem.  {{FilePendingMessageCursor}} implements it but the rest of the cursors (notably {{StoreQueueCursor}}) simply delegate back to {{addMessageLast}} in the parent class.  So part of this fix may require implementing {{tryAddMessageLast}} across more cursors.
> Here is part of the thread dump showing the stuck producer:
> {code}
> "ActiveMQ Transport: ssl:///192.168.3.142:38589" daemon prio=10 tid=0x00007fb46c006000 nid=0x3b1a runnable [0x00007fb4b8a0d000]
>    java.lang.Thread.State: TIMED_WAITING (parking)
>         at sun.misc.Unsafe.park(Native Method)
>         - parking to wait for  <0x00000000cfb13cd0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
>         at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:226)
>         at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2176)
>         at org.apache.activemq.usage.Usage.waitForSpace(Usage.java:103)
>         at org.apache.activemq.usage.Usage.waitForSpace(Usage.java:90)
>         at org.apache.activemq.usage.Usage.waitForSpace(Usage.java:80)
>         at org.apache.activemq.broker.region.cursors.FilePendingMessageCursor.tryAddMessageLast(FilePendingMessageCursor.java:235)
>         - locked <0x00000000d2015ee0> (a org.apache.activemq.broker.region.cursors.FilePendingMessageCursor)
>         at org.apache.activemq.broker.region.cursors.FilePendingMessageCursor.addMessageLast(FilePendingMessageCursor.java:207)
>         - locked <0x00000000d2015ee0> (a org.apache.activemq.broker.region.cursors.FilePendingMessageCursor)
>         at org.apache.activemq.broker.region.cursors.StoreQueueCursor.addMessageLast(StoreQueueCursor.java:97)
>         - locked <0x00000000d1f20908> (a org.apache.activemq.broker.region.cursors.StoreQueueCursor)
> {code}


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