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From "Roger Hoover" <roger.hoo...@gmail.com>
Subject Re: Priority queue/semantics of consumer priority
Date Tue, 12 Feb 2008 18:17:26 GMT
Thanks for the link, Joe.
So it looks like consumer priority is used by the broker to determine which
subscriber to choose as the exclusive consumer?

Does AMQ support message priorities?  This ticket would suggest the answer
is no (http://issues.apache.org/activemq/browse/AMQ-122)

Does anyone have any recommendations for achieving the semantics of a
priority queue?

Here's what I was thinking of doing:
- Put the messages with different priorities into different queues
- Have the clients (STOMP is this case) subscribe to the various priority
queues
- The clients select() on all the sockets and when data is ready to be read,
the client reads from socket of the highest priority queue.

Suggests welcome.  Thanks,

Roger

On Feb 12, 2008 5:36 AM, ttmdev <joe.fernandez@ttmsolutions.com> wrote:

>
> Hi Roger,
>
> I'd disregard the consumer priority feature; it does not function as
> described in the consumer priority page.
>
> Here's the exclusive consumer web page.
>
> http://activemq.apache.org/exclusive-consumer.html
>
> Joe
> www.ttmsolutions.com
>
>
>
>
>
>
> Roger Hoover wrote:
> >
> > I want to implement a priority queue (message delivery ordered by
> > priority)
> > and am trying to figure out what consumer priority means.
> >
> > After looking over the documentation (
> > http://activemq.apache.org/consumer-priority.html) and these email
> > threads,
> > the semantics of consumer priority are still not entirely clear to me.
> >
> http://www.nabble.com/Consumer-Priority-on-AMQ-5.0-to14369093s2354.html#a14369093
> >
> http://www.nabble.com/Using-different-consumer-priorities-in-the-same-connection-td14722765s2354.html#a14722765
> >
> > - Does consumer priority control the order of message delivery or does
> it
> > influence which consumer messages get sent to?
> >
> > - If it controls delivery order, what effect does setting a priority on
> a
> > consumer have?  It would seem like the priority should be set per
> message.
> >
> > - What does Hiram mean by "exclusive consumers"?  Is this different from
> > each message being delivered to one and one only consumer?
> >
> > - What is the weighting algorithm for priorities?
> >
> > - What is the ballpark performance penalty for priority evaluation on
> the
> > broker?
> >
> > - Does the priority value have any particular significance other than
> > being
> > greater or less than other priority levels?
> >   - Is there a maximum priority value?
> >   - Does priority 0 have any special meaning?
> >
> > - Does the feature exist in AMQ 4.1.1?
> >
> > - Are there any gotchas when using it with STOMP?
> >
> > I appreciate any info anyone can provide.
> >
> > Cheers,
> >
> > Roger
> >
> >
>
> --
> View this message in context:
> http://www.nabble.com/Priority-queue-semantics-of-consumer-priority-tp15427022s2354p15433256.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>
>

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