[jira] [Updated] (AMQNET-521) LRUCache not working correctly, which can cause Memory Leak and Slowdown

["Markus Jung (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AMQNET-521?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Markus Jung updated AMQNET-521:
-------------------------------
    Attachment: LRUCache.cs.patch

The attached patch file is the fix we use.

> LRUCache not working correctly, which can cause Memory Leak and Slowdown
> ------------------------------------------------------------------------
>
>                 Key: AMQNET-521
>                 URL: https://issues.apache.org/jira/browse/AMQNET-521
>             Project: ActiveMQ .Net
>          Issue Type: Bug
>          Components: ActiveMQ
>    Affects Versions: 1.7.1
>            Reporter: Markus Jung
>            Assignee: Jim Gomes
>         Attachments: LRUCache.cs.patch
>
>
> Reason: Duplicates are not handled correctly. Which causes one of the internal lists (entries) to grow over time until handling the numberous items increases processing overhead and cause a slowdown.
> Background: We are pulling a queue using n consumers with zero prefetch for maximum round robin. (Using Failover-Transport.)
> Processing a message can take time from split a second to several hours. Prefetching a message would not be good. Nether-the-less this is a good way to do it, we discovered increasing memory usage and slowing down of our "workers".
> After a worker processed a task a new call to consumer.Receive(timeout) causes to send a new MessagePull request, which is put into the messageCache using the same id.
> (ProcessMessagePull in ConnectionStateTracker)
> This causes the grow.
> Reason: In LRUCache.this method, the call to entries.Remove uses value and not currentValue.



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