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https://issues.apache.org/jira/browse/ARTEMIS-1011?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15892638#comment-15892638
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Justin Bertram commented on ARTEMIS-1011:
-----------------------------------------
Couple of things:
* This is use-case that should be handled so kudos for identifying it.
* I'm not clear why you need the {{AtomicLong messageCountSnapshot}}. Couldn't
you just invoke {{getMessageCount()}}?
* Invoking {{getMessageCount()}} will lock the queue and therefore negatively
impact performance for high-throughput use-cases. We may want to add some kind
of optimization to {{getRate()}} to avoid that call if at all possible or
perhaps avoiding the call to {{getRate()}} unless absolutely necessary.
* This changes the semantics of the method such that it no longer returns the
rate of message production on the queue between invocations so it would
probably be good to rename the method to something more accurate.
> Slow consumer detection - producer msg/s rate for queue should take into
> account messages which are already in queue
> --------------------------------------------------------------------------------------------------------------------
>
> Key: ARTEMIS-1011
> URL: https://issues.apache.org/jira/browse/ARTEMIS-1011
> Project: ActiveMQ Artemis
> Issue Type: Bug
> Components: Broker
> Affects Versions: 1.5.3
> Reporter: Miroslav Novak
> Fix For: 2.0.0, 1.5.4
>
>
> There is still a problem how producer msg/s rate is calculated in
> {{QueueImpl.getRate()}} for slow consumer detection. It calculates only
> messages added during the last slow consumer check period. As this is used to
> figure out, in which msg/s rate the queue could serve the consumer then it
> should also take into account messages which are already in queue at the
> start of queueRateCheckTime period.
> Current implementation is problem for cases when messages are sent to queue
> in bursts, for example producer sends 1000s messages in a few seconds and
> then stops and will do that again in 1 hour. QueueImpl.getRate() method
> returns 0 msg/s for slow consumer check period set to for example 5 min and
> slow consumer detection will be skipped.
> I tried to fix it by following change to QueueImpl.getRate() method and seems
> to be ok, wdyt?
> {code}
> private final AtomicLong messageCountSnapshot = new AtomicLong(0);
> public float getRate() {
> long locaMessageAdded = getMessagesAdded();
> float timeSlice = ((System.currentTimeMillis() -
> queueRateCheckTime.getAndSet(System.currentTimeMillis())) / 1000.0f);
> if (timeSlice == 0) {
> messagesAddedSnapshot.getAndSet(locaMessageAdded);
> return 0.0f;
> }
> return BigDecimal.valueOf(((locaMessageAdded -
> messagesAddedSnapshot.getAndSet(locaMessageAdded)) +
> messageCountSnapshot.getAndSet(getMessageCount())) / timeSlice).setScale(2,
> BigDecimal.ROUND_UP).floatValue();
> }
> {code}
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