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https://issues.apache.org/activemq/browse/AMQ-2159?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=50550#action_50550
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Yannick commented on AMQ-2159:
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We also discovered this problem because we were running out of memory even if a
Message Limit Strategy was activated.
> One evicted message out of two is delivered to the consumer
> -----------------------------------------------------------
>
> Key: AMQ-2159
> URL: https://issues.apache.org/activemq/browse/AMQ-2159
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.2.0
> Environment: Windows Xp, Java 5, ActiveMQ 5.2
> Reporter: Yannick
> Attachments: testActiveMQ.zip
>
>
> A problem in message eviction seems to cause a strange behavior of message
> delivery. After a slow consumer consumed it's prefetched messages, it start
> receiving one message out of two that were produced. When stepping into the
> sources I noticed that one message evicted out of two is dispatched to the
> destination even if no message have been consumed during that time. The
> problem seems to be in the class 'TopicSubscription'. This is what I found:
> - When a message is discarded dequeueCounter is incremented.
> - Then next time a message arrives it is evicted then dispatchMatched is
> called.
> - Because dequeueCounter have been called without any message dispatched,
> isFull() return false.
> - As a result it assumes there is an empty room in the prefetch and dispatch
> the message.
> The following example show what I expect against what I get when I produce
> 100 messages with a unique ID then consume 10 message and output the message
> ID. Prefetch size is 5. and constantPendingMessageLimitStrategy limit="5"
> Expected:
> 0, 1, 2, 3, 4, 95, 96, 97, 98, 99
> What I really get
> 0, 1, 2, 3, 4, 5, 7, 9, 11, 13
> I made a test application and a unit test, I didn't found how to attach it to
> the issue.
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