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From "wojtek.z" <wojtek.zinc...@autodata.net>
Subject Re: Retrieving Messages Out of Sequence
Date Tue, 18 Sep 2007 13:45:41 GMT

Thanks for the replies guys

Maybe to clarify I am using a custom message listener to retrieve the
messages. I recently tried to set "exclusive consumer" as well as
"maxSessions=1" but I still get the messages out of order. The strange thing
I found was that if i put messages on the queue and my listener isnt running
and then i turn it, the messages get retrieved as 3 , 2 , 1. If I throw two
sets of 3 messages they get retrieved as 3, 2, 1, 3, 2, 1, only sometimes.

When I have my listener running as I am putting messages on the queue they
are retrieved as 1, 2, 3. Can anyone help me understand the inconsistency in
behavior ?

Here is my config sample

	<!-- ActiveMQ JCAConnectors -->
	<bean id="InQueConnector1" class="org.jencks.JCAConnector">
		<property name="jcaContainer" ref="jencks" />
		  <!-- Queue details -->
		<property name="activationSpec">
		    <bean class="org.apache.activemq.ra.ActiveMQActivationSpec">
		      <property name="destination"
value="ActiveMQ.In.Queue1?consumer.exclusive=true"/>
		      <property name="destinationType" value="javax.jms.Queue"/>
   		      <property name="maxSessions" value="1"/>
		    </bean>
		</property>
		  		
		<property name="ref" value="InQueListenerTarget1"/>
	</bean>




Daryl Richter-3 wrote:
> 
> 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
> 
> 
> 
> 
> 
> 
> 

-- 
View this message in context: http://www.nabble.com/Retrieving-Messages-Out-of-Sequence-tf4470245s2354.html#a12757410
Sent from the ActiveMQ - User mailing list archive at Nabble.com.


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