title: slow jms mq message sending
body: <p>We are using Websphere MQ 7.5 with the Javax-JMS-classes and have some performance-problems, which aren't reproducable. </p>
  
  <p>I have isolated the performance-issue to these two method-calls <a href="https://docs.oracle.com/javaee/7/api/javax/jms/Connection.html#createSession--" rel="nofollow"><code>createSession</code></a> and <a href="http://docs.oracle.com/javaee/1.4/api/javax/jms/MessageProducer.html#send(javax.jms.Message)" rel="nofollow"><code>send</code></a>.</p>
  
  <p>These two calls sometimes take a large amount of time(> 300ms per message). Often there is a <code>Object.wait</code> call which causes the slowdown. So maybe jms is waiting for resources.</p>
  
  <p>Sometimes I can send 500 messages without any occurence of that issue, but suddenly it's really slow. It isn't possible that the problem is in our code, because every step before doesn't take much time. Only these two JMS method calls.</p>
  
  <p>So my question is, what could be the cause for the sudden performance-drop? </p>
  
  <p>Is it possible to debug it by using the queuemanager-logs? </p>
  
  <p>Any idea is helpful.</p>
  
  <p><strong>Edit</strong>:</p>
  
  <p>We are using client-bindings and the SHARECNV-setting is set to 10.</p>