[
https://issues.apache.org/jira/browse/AMQ-5712?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14492775#comment-14492775
]
Christopher L. Shannon commented on AMQ-5712:
---------------------------------------------
Great, thanks for your help and for taking a look this issue in detail as it is
very important to us and it is causing us a lot of problems. I suspected my
patch may not be the best solution and would need some rework because when the
tryAdd method times out with my patch nothing is actually done with that
message. After returning false it just continues on and the message gets lost
as you pointed out. However, I figured submitting something that at least
demonstrated the issue as well as a unit test where it is consistently
reproducible would help get things started towards finding the best solution to
fix the issue permanently.
Chris
> 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}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
