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Posted to dev@activemq.apache.org by "Christopher L. Shannon (JIRA)" <ji...@apache.org> on 2015/04/10 00:15:12 UTC
[jira] [Comment Edited] (AMQ-5712) Broker can deadlock when using
queues while producers wait on disk space
[ https://issues.apache.org/jira/browse/AMQ-5712?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14488392#comment-14488392 ]
Christopher L. Shannon edited comment on AMQ-5712 at 4/9/15 10:15 PM:
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I started working on a unit test today to replicate this issue but I haven't quite been able to reproduce the bug in a unit test yet. In my simple unit test (just one producer), when the temp storage fills the broker detects this at line 821 of {{Queue.java}} when {{checkUsage(context, producerExchange, message);}} is called.
When I run our real broker, it gets past that line until it hits the {{cursorAdd}} method and ultimately gets stuck spinning in {{FilePendingMessageCursor.java}} on line 235 at {{if (systemUsage.getTempUsage().waitForSpace(maxWaitTime))}}
Our broker is configured for persistent messaging, but the producer is sending non-persistent messages which is why the temp store is used. I'll continue to try and put a test together next week or figure out what's different about my set up. We have some custom code that we are using so it could be that or it could just be our configuration. (Maybe something in the Queue Policy that we have configured) What I do know is that when I apply my pull request it fixes the dead lock and the broker no longer gets stuck on line 235 of {{FilePendingMessageCursor.java}}
was (Author: christopher.l.shannon):
I started working on a unit test today to replicate this issue but I haven't quite gotten it to work in a unit test yet. In my simple unit test (just one producer), when the temp storage fills the broker detects this at line 821 of {{Queue.java}} when {{checkUsage(context, producerExchange, message);}} is called.
When I run our real broker, it gets past that line until it hits the {{cursorAdd}} method and ultimately gets stuck spinning in {{FilePendingMessageCursor.java}} on line 235 at {{if (systemUsage.getTempUsage().waitForSpace(maxWaitTime))}}
Our broker is configured for persistent messaging, but the producer is sending non-persistent messages which is why the temp store is used. I'll continue to try and put a test together next week or figure out what's different about my set up. We have some custom code that we are using so it could be that or it could just be our configuration. (Maybe something in the Queue Policy that we have configured) What I do know is that when I apply my pull request it fixes the dead lock and the broker no longer gets stuck on line 235 of {{FilePendingMessageCursor.java}}
> 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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