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From Joe Fernandez <joe.fernan...@ttmsolutions.com>
Subject Re: Question about Queue destinations in network of brokers
Date Wed, 07 Oct 2009 10:45:50 GMT

I don't have a date, but from what I understand it is getting very close to
being released.  

Joe
http://www.ttmsolutions.com


farshad wrote:
> 
> Hi Joe,
> 
> Thanks again for your reply.  Do you know when 5.3 is going to be
> released?
> 
> -Farshad
> 
> 
> Joe Fernandez wrote:
>> 
>> Hi Farshad,
>> 
>> You may have encountered the following problem:
>> http://issues.apache.org/activemq/browse/AMQ-2135
>> 
>> It is a rather nasty problem where messages become stuck in one of the
>> NoB's brokers. That is, a broker does not forward the messages to other
>> brokers in the NoB that have valid subscriptions. 
>> 
>> Not until you connect a consumer to one of the brokers that houses the
>> stuck messages, will the broker  dispatch  the message to the consumer.
>> It has to do with subscription management. 
>> 
>> There is this patch that addresses the problem, but only for
>> 'fully-connected' NoB topologies. 
>> 
>> http://issues.apache.org/activemq/secure/attachment/17800/AMQ-2135-Patch-03182009.patch
>> 
>> If you're using a ring or line topology, the patch won't work and may
>> make matters worse. 
>> 
>> You may also encounter a situation where some of the brokers’ transport
>> threads are parked (stuck) on a Java CountDownLatch object and are thus
>> unable to service their respective transport. A transport in this case is
>> used to connect two brokers and the message broker assigns a worker
>> thread to service that transport. When this occurs, the NoB is
>> compromised. Here are some relevant links for this problem. 
>> 
>> http://www.nabble.com/Network-connector-failover-problems-td10224971.html#a10275742
>> http://issues.apache.org/activemq/browse/AMQ-1827
>> 
>> Our testing indicated that the above 'parked thread' problem only occurs
>> with the failover connector. We were never able to reproduce it with the
>> static connector. 
>> 
>> I would also recommend moving to 5.3 when possible. 
>> 
>> Joe
>> http://www.ttmsolutions.com
>> 
>> 
>> farshad wrote:
>>> 
>>> Hi Joe,
>>> 
>>> Thank you for your reply.  So, I set dynamicOnly to "true" and
>>> networkTTL to 4.  The sender code puts messages in the queue and the
>>> receiver code connects and sometimes it gets all the messages and
>>> somtimes it gets some of them.  I have to reconnect to get the rest of
>>> them.  Also, if I shut down the broker that the messages were sent thru,
>>> no messages can be received.  In my activemq.xml I have one broker
>>> definition and then copy the same config file into the all broker
>>> machines.  Should each broker have its own unique broker definition? 
>>> What is the use of staticallyIncludedQuues?
>>> 
>>> Here's my config file:
>>> 
>>>  <destinations>
>>>            <queue physicalName="Document.QUEUE" />
>>>  </destinations>
>>> 
>>> <networkConnector name="myHosts"
>>> uri="static://(tcp://host1:61616,tcp://host2:61616,tcp://host3:61616,tcp://host4:61616)">
>>>              networkTTL=4
>>>              dynamicOnly=true
>>> </networkConnector>
>>> 
>>> <transportConnectors>
>>>       <transportConnector name="openwire" uri="tcp://localhost:61616"
>>> discoveryUri="multicast://default"/>
>>> </transportConnectors>
>>> 
>>> Thank you,
>>> FarshadK
>>> 
>>> 
>>> Joe Fernandez wrote:
>>>> 
>>>> You should use the static and not failover connector to configure your
>>>> network of brokers. Also make sure that you have the appropriate values
>>>> assigned to the networkTTL and dynamicOnly parameters.  
>>>> 
>>>> http://activemq.apache.org/networks-of-brokers.html
>>>> 
>>>> Joe
>>>> http://www.ttmsolutions.com
>>>> 
>>>> 
>>>> 
>>>> farshad wrote:
>>>>> 
>>>>> I have a network of 4 brokers configuration with
>>>>> failover://(tcp://host1:61616,tcp://host2:61616,...) defined.  My
>>>>> first piece of java code connects to one of these hosts (randomly) and
>>>>> puts some messages in a queue destination (e.g. Document.QUEUE).  A
>>>>> second piece of java code connects to another one of these hosts and
>>>>> fails to read the messages.  Is this expected behaviour?  If I connect
>>>>> to one host and put messages in a queue and the host goes down what do
>>>>> I have to do to receive my messages connecting to another host in the
>>>>> network?
>>>>> 
>>>>> Thank you in advance,
>>>>> FarshadK
>>>>> 
>>>> 
>>>> 
>>> 
>>> 
>> 
>> 
> 
> 

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