Is ActiveMQQueue really a Queue?

[itamara <av...@gmail.com>]

hi ActiveMQ users

I'm new to ActiveMQ (bet you never heard that before :-)).

I'm using org.apache.activemq.command.ActiveMQQueue as my destination.
For debugging purposes I log the events of sending the message and the
events of MessageListener.onMessage. I find that...

The ActiveMQQueue does not seem to act as a queue - in the "first in, first
out" sense.

Is that so?

Is it configurable?

Why do I care? Because it looks as some messages can wait in the queue
forever, can be forgotten there. And though it's not exactly my case, some
might want a pure FIFO queue implementation.

thanks for any help and clarification.
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Re: Is ActiveMQQueue really a strict FIFO queue?

[itamara <av...@gmail.com>]

The first step of solving a problem is asking the right question.

(or is it acknowledging it, and the right question is only the second?
:confused:)

I was looking for something else. Thanks a lot for all the repliers. Your
help did not go unappreciated.

Please bare with me to the following thread: 
http://www.nabble.com/Maintaining-Message-Uniqueness-in-a-Queue-td25660461.html
Maintaining Message Uniqueness in a Queue .

Thanks.
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Re: Is ActiveMQQueue really a strict FIFO queue?

[Fredrik Jonson <fr...@myrealbox.com>]

Bruce Snyder wrote:
> itamara wrote:
>
> > The ActiveMQQueue does not seem to act as a queue - in the "first in, 
> > first out" sense.
> 
>  It sounds like you might want to configure total ordering.
>  http://activemq.apache.org/total-ordering.html

Itamara mentions only queues and not topics. Does activemq really enforce a
strict order of message consumption on queues too?

http://activemq.apache.org/per-destination-policies.html

According to that document it sounds like multiple queue consumers may
behave in as a strict FIFO queue when the prefetch limit is set to 1? Which
by the sound of it would also makes the consumption serial, and perhaps not
much faster than only having a single consumer anyway?

Itamara, do observe the difference between queues and topics and that it
normally is the broker configuration that controls the behaviour of the
physical queue, not the ActivemMQQueue java class.

http://activemq.apache.org/how-does-a-queue-compare-to-a-topic.html

-- 
Fredrik Jonson

Re: Is ActiveMQQueue really a Queue?

[Bruce Snyder <br...@gmail.com>]

On Sat, Sep 26, 2009 at 7:17 AM, itamara <av...@gmail.com> wrote:
>
> hi ActiveMQ users
>
> I'm new to ActiveMQ (bet you never heard that before :-)).
>
> I'm using org.apache.activemq.command.ActiveMQQueue as my destination.
> For debugging purposes I log the events of sending the message and the
> events of MessageListener.onMessage. I find that...
>
> The ActiveMQQueue does not seem to act as a queue - in the "first in, first
> out" sense.
>
> Is that so?
>
> Is it configurable?
>
> Why do I care? Because it looks as some messages can wait in the queue
> forever, can be forgotten there. And though it's not exactly my case, some
> might want a pure FIFO queue implementation.
>
> thanks for any help and clarification.

It sounds like you might want to configure the total ordering option:

http://activemq.apache.org/total-ordering.html

Bruce
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