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https://issues.apache.org/jira/browse/AMQ-6239?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Timothy Bish updated AMQ-6239:
------------------------------
    Fix Version/s: 5.14.0

> Performance issue in PrioritizedPendingListIterator
> ---------------------------------------------------
>
>                 Key: AMQ-6239
>                 URL: https://issues.apache.org/jira/browse/AMQ-6239
>             Project: ActiveMQ
>          Issue Type: Improvement
>          Components: Broker
>    Affects Versions: 5.12.2
>            Reporter: Martin Lichtin
>             Fix For: 5.14.0
>
>         Attachments: AMQ-6239-yourkit-1.jpg, PrioritizedPendingList.java.patch
>
>
> Sending and consuming 5000 messages to/from a queue, one can see heavy CPU 
> use on the broker side (v 5.12.2).
> Yourkit shows 
> PrioritizedPendingList$PrioritizedPendingListIterator.<init>
> as a hot spot method. It calls ArrayList.add(Object) around 12 mio times.
> Situation is that FilePendingMessageCursor.isEmpty() iterates over in-memory 
> messages and therefore (as it is a prioritized queue) uses 
> PrioritizedPendingListIterator which uses OrderedPendingList.getAsList() 
> which overall turns out to be an expensive method as it converts the 
> self-managed linked list to a Java ArrayList and then this list is filled 
> into another ArrayList managed by PrioritizedPendingListIterator.
> PrioritizedPendingListIterator could be improved to walk the priority lists 
> via OrderedPendingList iterators, as these are implemented efficiently. 



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