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From Tim Bain <tb...@alumni.duke.edu>
Subject Re: Expired non-persistent messages on topic appear to not be discarded
Date Fri, 20 Jan 2017 13:48:41 GMT
Are your slow consumers still receiving messages properly when this
happens?  Are there any indications that this is a "real" problem rather
than just a bug in the JMX counters?

Tim

On Jan 19, 2017 8:38 AM, "Veloso, Vasco (Coriant - PT/Lisbon)" <
Vasco.Veloso@coriant.com> wrote:

> Hello,
>
>
>
> I’m using ActiveMQ 5.14.3 to test and try to find a suitable configuration
> for a scenario where we have multiple producers and multiple consumers of a
> topic, non-durable, in which some consumers may be quite slow. Also, some
> messages have TTL defined and others do not.
>
>
>
> By looking at the JMX counters for the topic, InFlightCount remains stable
> at the prefetch value for consumers. However once messages begin to expire,
> it looks like they are not discarded:
>
>
>
> ·         ExpiredCount starts to increase as messages time out;
>
> ·         InFlightCount starts to increase at the same rate as
> ExpiredCount.
>
>
>
> JMX counters for slow consumers follow the same pattern. They remain
> stable until messages begin to expire: MessageCountAwaitingAcknowledge
> remains near PrefetchSize. When messages expire then
> MessageCountAwaitingAcknowledge starts to increase as well.
>
>
>
> These counters will never decrease or stabilize as long as there are
> messages being produced.
>
>
>
> I tried many settings but I still don’t understand what is going on. It
> appears as if expired messages are forwarded to consumers or expire on
> consumers? However for this test the broker, producers and consumers are on
> the same machine so there is no clock drift. And if messages would expire
> on consumers, wouldn’t they be dropped from the topic as well?
>
>
>
> My broker configuration and test producer/consumer code is attached for
> your reference.
>
>
>
> I hope that someone can shed some light on this matter, since I can’t make
> heads or tails of it at this time.
>
>
>
> Thanks!
>
>
>
> Vasco Veloso
>
>
>

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