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From Jordan Zimmerman <>
Subject Re: DistributedQueue - subscriber not receiving all messages
Date Wed, 02 Jul 2014 14:42:15 GMT
I don’t see an issue from that code snippet. What does the producer side look like? Maybe
the producer is taking the messages?


From: Donald Laidlaw
Date: July 2, 2014 at 5:01:38 AM
Subject:  DistributedQueue - subscriber not receiving all messages  

Hi All,  

Despite the advice not to use Zookeeper for queues, I thought I would try  
it for a very low volume application rather than install a dedicated  
messaging system. I already had zookeeper, so it seemed like a decent fit.  

I create a DistributedQueue<T> for my type and provide the serializer, path,  
client, and the consumer interface. I then start it and immediately  
receive any messages that are already in the queue.  

Meanwhile in another JVM (same machine) I connect to the same path with a  
DistributedQueue<T> with a null consumer interface parameter and send new  
messages. Those messages never get consumed by the consumer I created earlier.  
I can start the zookeeper shell and actually see the messages in the path.  
So I know the messages are there. If I stop the original consumer (stop the whole  
JVM, not just the DistributedQueue object)and start it again then it  
will consume the messages that were waiting there.  

I don't think this is the expected behavior, and I am not sure why it is  
happening. Can anyone see something I missed?  

Java 8 on Mac OSX Mavericks, fully updated  
Zookeeper 3.4.6  
Curator 2.4.2  

The Code ...  

QueueBuilder<NodeStateEvent> builder = QueueBuilder.builder(  
new JsonQueueSerializer<>(NodeStateEvent.class),  

DistributedQueue<NodeStateEvent> queue = builder.buildQueue();  

// At this point events already in the queue arrive and are processed by the  
// queueConsumer without any issues. However, no newly queued events are  
// ever received.  

Don Laidlaw  
866 Cobequid Rd.  
Lower Sackville, NS  
B4C 4E1  
Phone: 1-902-576-5185  
Cell: 1-902-401-6771  

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