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Posted to users@qpid.apache.org by Raphael Fuchs <ra...@gmail.com> on 2014/09/29 22:09:34 UTC
Duplicate Messages
Hello,
I am new to Qpid, starting to work on an extensive projects code base.
I am trying to find the spot in the documentation where guarantees of the
messaging system are discussed. For example: in case of a network problem,
could it happen that the broker sends the same message twice?
There is some duplicate checking and I would like to confirm it is
necessary.
Thanks for your help!
Raphael
Re: Duplicate Messages
Posted by Pavel Moravec <pm...@redhat.com>.
Hi,
you can get more duplicated messages, depending on your client's capacity/prefetch. The higher capacity is, the more messages the broker can send to the client without getting acknowledgement to prior messages. I.e. the bigger message throughput you get (until some threshold). On the other side, higher capacity means more messages in-flight/in-doubt.
Every message that the broker is re-delivering should have message header redelivered:true.
Kind regards,
Pavel
----- Original Message -----
> From: "Andreas Welchlin" <an...@welchlin.de>
> To: users@qpid.apache.org
> Sent: Tuesday, September 30, 2014 10:20:18 AM
> Subject: Re: Duplicate Messages
>
> Hi Steve,
>
> I wonder how to check for duplicates, as well. I create topics using
> --sequence like:
>
> qpid-config -b localhost exchange topic test_topic --durable
> --sequence
>
>
> I understood that the the order of messages is guaranteed, then. This
> means a duplicate message can only be the last message, I received.
> Otherwise the sequence order would have been broken.
>
> Do you think this assumption is right?
>
> Kind Regards,
> Andreas
>
>
>
>
> Am 29.09.2014 um 22:28 schrieb Steve Huston:
> > Hi Raphael,
> >
> >> I am new to Qpid, starting to work on an extensive projects code base.
> > Welcome!
> >
> >> I am trying to find the spot in the documentation where guarantees of the
> >> messaging system are discussed. For example: in case of a network problem,
> >> could it happen that the broker sends the same message twice?
> > Yes:
> > http://qpid.apache.org/releases/qpid-0.30/programming/book/acknowledgements.html
> >
> >> There is some duplicate checking and I would like to confirm it is
> >> necessary.
> > Yes, it is.
> >
> > -Steve Huston
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: users-unsubscribe@qpid.apache.org
> > For additional commands, e-mail: users-help@qpid.apache.org
> >
>
>
>
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Re: Duplicate Messages
Posted by Andreas Welchlin <an...@welchlin.de>.
Hi Steve,
I wonder how to check for duplicates, as well. I create topics using
--sequence like:
qpid-config -b localhost exchange topic test_topic --durable
--sequence
I understood that the the order of messages is guaranteed, then. This
means a duplicate message can only be the last message, I received.
Otherwise the sequence order would have been broken.
Do you think this assumption is right?
Kind Regards,
Andreas
Am 29.09.2014 um 22:28 schrieb Steve Huston:
> Hi Raphael,
>
>> I am new to Qpid, starting to work on an extensive projects code base.
> Welcome!
>
>> I am trying to find the spot in the documentation where guarantees of the
>> messaging system are discussed. For example: in case of a network problem,
>> could it happen that the broker sends the same message twice?
> Yes:
> http://qpid.apache.org/releases/qpid-0.30/programming/book/acknowledgements.html
>
>> There is some duplicate checking and I would like to confirm it is necessary.
> Yes, it is.
>
> -Steve Huston
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@qpid.apache.org
> For additional commands, e-mail: users-help@qpid.apache.org
>
---------------------------------------------------------------------
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RE: Duplicate Messages
Posted by Steve Huston <sh...@riverace.com>.
Hi Raphael,
> I am new to Qpid, starting to work on an extensive projects code base.
Welcome!
> I am trying to find the spot in the documentation where guarantees of the
> messaging system are discussed. For example: in case of a network problem,
> could it happen that the broker sends the same message twice?
Yes:
http://qpid.apache.org/releases/qpid-0.30/programming/book/acknowledgements.html
> There is some duplicate checking and I would like to confirm it is necessary.
Yes, it is.
-Steve Huston
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