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From Rick Blair <rick.bl...@boeing.com>
Subject Re: Problem with losing acks(?)
Date Tue, 14 Oct 2008 14:06:33 GMT
Hi all,

A little more information.

I looked at the acks that were being sent back from the subscriber.  Under
heavy load the messageCount field in the ack message sometimes goes
negative.  Once that happens, it is not long before the subscriber quits
sending acks. I have tried small and large values for
prefetchSize(100,100,10000) but it makes no difference.

 I have worked around this problem by setting optimizeAcknowlege to false.
 
-- 
Tìoraidh!

Rick Blair




> From: Joe Fernandez <joe.fernandez@ttmsolutions.com>
> Reply-To: <users@activemq.apache.org>
> Date: Sun, 12 Oct 2008 18:17:05 -0700 (PDT)
> To: <users@activemq.apache.org>
> Subject: Re: Problem with losing acks(?)
> 
> 
> When creating sessions for your subscribers, what ack mode (AUTO, CLIENT, or
> DUPS_OK) are you using and are your sessions transacted?
> 
> Joe
> Get a free ActiveMQ user guide @ http://www.ttmsolutions.com
> 
> 
> Rick Blair wrote:
>> 
>> Hi all,
>> 
>> I am using ActiveMQ version 5.1 in a pub/sub system.  The broker is
>> embedded
>> with the publishers.  The publishers publish to 2 main topics with
>> selectors.  I have many subscribers distributed on the network. The
>> subscriptions are based on the selectors.  The messages are object
>> messages.
>> 
>>   During execution one subscriber(not always the same one) seems to stop
>> sending acks.  
>> 
>> In the subscriber I still see the onMessage method call being called.
>> However on the broker, using jconsole looking at the subscription, the
>> number of messages waiting for ack = the prefetch size and the number of
>> queued messages increases.
>> 
>>   This goes on until the broker memory limit hits 100% and all message
>> flow
>> stops. 
>> 
>>  We have tried to set the policies that discard older messages, but that
>> did
>> not help.  The message discard count does increase to a point, then
>> remains
>> constant, while the enqueue count still increases.  Also at this time many
>> of the stats go negative.  This very often occurs right after startup
>> under
>> heavy load on the producers.  Thread dumps show no threads blocked, the
>> CPU
>> is not heavily loaded. GC does not seem to an issue.
>> 
>> Any suggestions?
>>  
>> -- 
>> Tìoraidh!
>> 
>> Rick
>> 
>> 
>> 
> 
> -- 
> View this message in context:
> http://www.nabble.com/Problem-with-losing-acks%28-%29-tp19934087p19947672.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
> 


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