title: RabbitMQ queues pile up with messages over a period of time even though there are listeners associated with those queues
body: <p>I have a situation in my rabbitmq setup. My scenario is as below,</p>
  
  <p><strong>Setup:</strong></p>
  
  <ol>
  <li>There are 2 Virtual machines involved.</li>
  <li>Both the VMs are sending 25mb size messages every  7 seconds in loop.</li>
  <li>There are shovels setup for transmitting the messages between the machines.</li>
  <li>Both the machines have listeners to consume the messages sent by the other machine.</li>
  <li>Listeners just consume the messages and comes out. There is no processing involved at the listener side.</li>
  <li>There rabbitmQ broker is <strong>SSL enabled</strong>.</li>
  <li>I am using <strong>Spring RabbitMq</strong>.</li>
  <li>I am using <strong>SimpleMessageListenerContainer</strong> for listening.</li>
  </ol>
  
  <p><strong>My Issues:</strong></p>
  
  <ol>
  <li><p>Over a period of time, say after 1.5 days of continuous message exchange, 
  there is accumulation of messages in the queues.</p></li>
  <li><p>The listeners are up but the consumption rate diminishes over a period of time 
  and the messages pile up in the queue.</p></li>
  <li><p>Some of the messages accumulated in the queue are in unacked state.</p></li>
  </ol>
  
  <p><strong>Things i want to try:</strong></p>
  
  <ol>
  <li>Increase the no. of listeners for the queue.</li>
  <li>Increase the prefetch count for the listener.</li>
  </ol>
  
  <p><strong>My Question</strong></p>
  
  <ol>
  <li>Why the messages got accumulated over the period of time.</li>
  <li>was there any network disturbance in between. Do i need to add extra parameters for listeners to tackle network disturbances.</li>
  </ol>
  
  <p>Please guide me here. I need help in fine tuning my setup to make it more robust.</p>