[jira] [Closed] (AMQ-6231) AbortSlowConsumer Strategy Inaccurate at default Sampling Rate

["Timothy Bish (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AMQ-6231?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Timothy Bish closed AMQ-6231.
-----------------------------
    Resolution: Workaround

Use of the AbortSlowAckConsumerStrategy will fix this.

> AbortSlowConsumer Strategy Inaccurate at default Sampling Rate
> --------------------------------------------------------------
>
>                 Key: AMQ-6231
>                 URL: https://issues.apache.org/jira/browse/AMQ-6231
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: JMS client
>    Affects Versions: 5.13.2
>         Environment: Any
>            Reporter: Justin Reock
>            Priority: Minor
>
> The default period check for the AbortSlowConsumer strategy is set to 30 seconds, however, the check itself is rather simple.  It checks the the number of messages in the prefetch buffer, and if that number is the same on the next check, that consumer is considered slow and is evicted.
> This can be inaccurate though, because there is no check that actually looks at whether the messages in the prefetch buffer are the same messages as before.  In other words, if the consumer processes all the messages in prefetch, and prefetch is refilled to the same number as the previous check, the consumer will be considered slow.
> You can reproduce this issue by starting with a queue with 5000 messages in it, and a prefetch of 1000.  Attach a consumer, and enable the Logger Plugin with logAll=true.  Set the AbortSlowConsumer strategy with default options.  After 30 seconds, even though the consumer has been reasonably processing messages, the Strategy will abort the consumer anyway, and you'll see a report from the Logger plugin that the consumer was slow.
> Then, repeat the same test, but set the AbortSlowConsumer checkPeriod down to a very small value, like 5 milliseconds.  The Consumer will never be considered slow.



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