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Posted to users@activemq.apache.org by bansalp <bp...@gmail.com> on 2014/09/29 13:36:33 UTC
Who will receive messages first virtual topic subscriber or logical
queue consumer?
Hi,
I am trying to use virtual topic and am unable to find answer to this
question, Can anybody help?
*Question*: I am sending to topic "VirtualTopic.Test" and have a logical
Queue "Consumer.A.VirtualTopic.Test". I have a subscriber (A) to topic and a
consumer (B) to physical queue corresponding to logical queue
("Consumer.A.VirtualTopic.Test"), among them (A and B) who will receive
message first A or B?
Thanks,
Pradeep
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Re: Who will receive messages first virtual topic subscriber or logical
queue consumer?
Posted by Andreas Gies <an...@wayofquality.de>.
Hi again,
the ActiveMQ gods may correct me, but the acknowledgement mode has nothing
to do with how the messages are actually dispatched. As I said before -
the easiest way
to grasp a Virtual topic is to to see it as a group of subscribers
acting as one.
Technically there is a queue underneath, but the broker handles that for
you. You could also
say that Virtual topics are a "Topic to Queue" bridge.
If you are asking how guaranteed delivery works:
For subscribers that are in fact real topic subscribers: those need to
be durable and you need
to send the messages persistently.
If you wanted to make a subscriber group "durable" you must
make sure the underlying queue exists by defining it in your broker
configuration. Otherwise
the group (and therefore the consumer) will only exist if at least one
group member is connected.
If you do this, you can work with normal acknowledgement operations.
Best regards
Andreas
On 29/09/14 14:32, bansalp wrote:
> Thanks Andreas
>
> So normal acknowledgement that works with persistent messages in case of
> topics with durable subscriber will not be there in case of virtual topic.
> Or will it be there and have some other behavior?
>
> Any idea on this ?
>
> Thanks,
> Pradeep
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.nabble.com/Who-will-receive-messages-first-virtual-topic-subscriber-or-logical-queue-consumer-tp4685974p4685977.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>
--
Andreas Gies
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Re: Who will receive messages first virtual topic subscriber or
logical queue consumer?
Posted by bansalp <bp...@gmail.com>.
Thanks Andreas
So normal acknowledgement that works with persistent messages in case of
topics with durable subscriber will not be there in case of virtual topic.
Or will it be there and have some other behavior?
Any idea on this ?
Thanks,
Pradeep
--
View this message in context: http://activemq.2283324.n4.nabble.com/Who-will-receive-messages-first-virtual-topic-subscriber-or-logical-queue-consumer-tp4685974p4685977.html
Sent from the ActiveMQ - User mailing list archive at Nabble.com.
Re: Who will receive messages first virtual topic subscriber or logical
queue consumer?
Posted by Andreas Gies <an...@wayofquality.de>.
Hi
I would dare to say thats fairly unpredictable.
If you are relying on the order in which multiple recipients of a topic
recieve a particular message,
then you should reconsider your appliaction design with respect to the
message flow.
In a nutshell, you can consider each virtual destination as a subscriber
group. Upon Sending a
message into a topic each subscriber AND each subscriber group will
consume an instance of
that message. Within each group you should not try to predict which
group member should
receive the message and across groups and normal subscribers you
shouldn't try to predict
the order in which the messages are dispatched to those.
This having said - if you combine virtual destinations with message
groups you can make
a group of messages stick to one group member. Again - the first message
of a group will
be consumed by a random member and the other messages of the group will
follow.
If you are using groups, don't forget to terminate message groups,
otherwise you might lose
the load balancing effect of a subscriber group.
My 2 ct
Andreas
On 29/09/14 13:36, bansalp wrote:
> Hi,
>
> I am trying to use virtual topic and am unable to find answer to this
> question, Can anybody help?
>
> *Question*: I am sending to topic "VirtualTopic.Test" and have a logical
> Queue "Consumer.A.VirtualTopic.Test". I have a subscriber (A) to topic and a
> consumer (B) to physical queue corresponding to logical queue
> ("Consumer.A.VirtualTopic.Test"), among them (A and B) who will receive
> message first A or B?
>
> Thanks,
> Pradeep
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.nabble.com/Who-will-receive-messages-first-virtual-topic-subscriber-or-logical-queue-consumer-tp4685974.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>
--
Andreas Gies
WoQ -- Way of Quality GmbH
Geschäftsführer & CTO
/eMail:/andreas@wayofquality.de <ma...@wayofquality.de>
/Tel:/ +49 151 23470823
/Fax:/ +49 1805 006534 2114
/Twitter:/ andreasgies /Skype:/ giessonic
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/Blog:/ <http://www.wayofquality.de/index.php/en/blog>
(http://www.wayofquality.de/index.php/en/blog)
/Github:/ <https://github.com/atooni> (https://github.com/atooni)
/Amtsgericht Landshut:/HRB 8352//
//
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bitte sofort den Absender telefonisch oder per Email und löschen Sie
diese Email und alle Kopien aus Ihrem System. Wir haften nicht für die
Unversehrtheit von Emails, nachdem sie unseren Einflussbereich verlassen
haben.
Disclaimer
This email may contain confidential and/or privileged information and is
intended solely for the attention and use of the named addressee(s). If
you are not the intended recipient, or a person responsible for
delivering it to the intended recipient, you are not authorized to and
must not disclose, copy, distribute, or retain this message or any part
of it without our authority. Please contact the sender by call or reply
email immediately and destroy all copies and the original message. We
are not responsible for the integrity of emails after they have left our
sphere of control.
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