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From Daryl Richter <ng...@comcast.net>
Subject Re: Retrieving Messages Out of Sequence
Date Tue, 18 Sep 2007 00:43:38 GMT
On Sep 17, 2007, at 8:35 PM, ttmdev wrote:

>
> The fact that there are multiple consumers should not matter,  
> because the
> messages are being assigned to "message groups" and AMQ should  
> dispatch all
> messages in a particular group to one consumer thus guaranteeing  
> the order
> of the messages in the group. See
> http://activemq.apache.org/message-groups.html

Sorry, I missed the part where he mentioned the groups.  The page I  
referenced does say that Message Groups should preserve order, so  
perhaps this is a bug.


>
> I have tried this and it works fine for me. Although, I am using an
> "asynchronous listener" and not polling for  messages.
>
>
> Daryl Richter-3 wrote:
>>
>> I assume you have multiple consumers.  In this case, order is *not*
>> preserved.
>>
>> Please see this page:
>>
>> http://activemq.apache.org/how-do-i-preserve-order-of-messages.html
>>
>>
>> On Sep 17, 2007, at 5:47 PM, wojtek.z wrote:
>>
>>>
>>> Howdy
>>>
>>> We are currently experiencing a bit of a problem with one of our
>>> applications which relates to messages being retrieved from the
>>> queue not in
>>> order / sequence.
>>>
>>> The basic idea is as follows
>>>
>>> We create 3 sets of messages
>>> Each message is tagged to a unique group
>>> Each message is tagged with a sequence number of 1 - 3
>>> Each message is sent to the queue separately
>>>
>>> Now when we view the queue the messages are lined up in order ( ie
>>> Group A =
>>> 1 , 2 , 3 )
>>>
>>> When we retrieve the messages though there is a very high chance
>>> that the
>>> messages dont come off the queue in the order they were put on
>>> there. If we
>>> have to sets of 3 messages ( from group A / B ) they tend to come
>>> across
>>> along the lines of A1 , B1 , A3 , B3 , A2 , B2. Now sometimes they
>>> shuffle
>>> around sometimes they come of the queue properly ( mostly only when
>>> 1 set of
>>> messages is active any more then that and the order breaks )
>>>
>>> The way we retrieve the messages is also very simple, we simply
>>> poll the
>>> queue and grab each message one by one.
>>>
>>> I did some reading and there were a few bugs reported back in
>>> version 4.0.x
>>> that mentioned these problems. I tried this exercise with versions
>>> 4.0.1 and
>>> 4.1.1 and neither seem to work correctly.
>>>
>>> Is there a work around to this problem or maybe I am just doing
>>> something
>>> very silly that is causing this. Anyway if someone could let me
>>> know that
>>> would be most beneficial. Thanks !
>>> -- 
>>> View this message in context: http://www.nabble.com/Retrieving-
>>> Messages-Out-of-Sequence-tf4470245s2354.html#a12745847
>>> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>>>
>>
>> -- 
>> Daryl
>> http://itsallsemantics.com
>>
>> "Under capitalism, man exploits man.
>>   Under communism, it's just the opposite."
>>      -- John Kenneth Galbraith
>>
>>
>>
>
> -- 
> View this message in context: http://www.nabble.com/Retrieving- 
> Messages-Out-of-Sequence-tf4470245s2354.html#a12747860
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>

--
Daryl
http://itsallsemantics.com

"We want great men who, when fortune frowns, will not be discouraged."
     -- Colonel Henry Knox, 1776






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