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From ttmdev <joe.fernan...@ttmsolutions.com>
Subject Re: Retrieving Messages Out of Sequence
Date Tue, 18 Sep 2007 00:35:50 GMT

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

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
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