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From Christian Schneider <>
Subject Re: Separate kahadb for queues and dead letter queues?
Date Fri, 29 Apr 2016 15:25:47 GMT
I just tested by sending messages into a queue test. Unfortunately the 
filter ">.DLQ" seems to include "test". So it seems everything after ">" 
is ignored.
Is there any way to express that I want all queues that end in DLQ?


On 29.04.2016 17:17, Christian Schneider wrote:
> I took a stab at creating a config with a separate kahadb for the DLQs:
>     <mKahaDB directory="${activemq.base}/data/kahadb">
>         <filteredPersistenceAdapters>
>             <filteredKahaDB queue=">.DLQ">
>                 <persistenceAdapter>
>                     <kahaDB />
>                 </persistenceAdapter>
>             </filteredKahaDB>
>             <filteredKahaDB>
>                 <persistenceAdapter>
>                     <kahaDB />
>                 </persistenceAdapter>
>             </filteredKahaDB>
>         </filteredPersistenceAdapters>
>     </mKahaDB>
> Does that make sense?
> I am unsure about the ">" wildcard as I am not sure if it can be used 
> at the start. All examples I found till now only seem to use it at the 
> end.
> I would be happy about a confirmation that what I do is correct or a 
> better solution.
> Christian
> On 29.04.2016 14:39, Christian Schneider wrote:
>> We have the issue that our journals at a customer are very large. We 
>> analyzed the messages in the system and found that most of the time
>> the normal queues stay at a very low number of messages near to 0. 
>> The only queues that hold messages for longer periods of time are the 
>> dead letter queues.
>> The journals are much bigger than the dead letter queue contents.
>> My assumption is that most of the journals only contain very few 
>> still needed messages and the ones they contain are the messages that 
>> now are in the dead letter queues.
>> Still the journals can not be cleaned up of course.
>> So what I would like to to is to use one kahadb for the regular 
>> queues and a different one for the dead letter queues. Does that make 
>> sense?
>> I will try to do this using "Multi(m) kahaDB persistence adapter": 
>> See
>> I also wonder if it would make sense that ActiveMQ cleans up its 
>> journals regularly. It could simply move all oldest messages to the 
>> newest jorunal to kind of pack if denser.
>> Would that work?
>> Christian

Christian Schneider

Open Source Architect

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