title: How can I reduce Qtime?
body: <p>I would like to know which parameters I need to change (if exist) to decrease the Qtime. </p>
  
  <pre><code> Qtime : The elapsed time (in milliseconds) between the arrival of the request (when the SolrQueryRequest object is created) and the completion of the request handler. It does not include time spent in the response writer formatting/streaming the response to the client.
  </code></pre>
  
  <p>I have logged curl responses when I update my documents and I have noticed that QTime increase  during the time. </p>
  
  <p>For example, my first response (corresponding to my first doc indexed) is 6293 ms. And after a large quantity of indexed documents, my QTime becomes longer : 1560781 ms so around 26 min !</p>
  
  <hr>
  
  <p><b>Edit</b></p>
  
  <p>First measure : 1 CSV file with 10000 solr docs -> QTime :6293ms</p>
  
  <p>Second measure : 1 CSV file with 10000 solr docs -> Qtime : 1560781 ms</p>
  
  <p>Delay between those measures = 32min 19s</p>
  
  <p>Number documents indexed during this interval : 26720000 documents </p>
  
  <hr>
  
  <p>I guess that is possible to improve that but I don't know witch settings modify to have better performances. </p>
  
  <p><b>Informations related to my system</b></p>
  
  <ul>
  <li>I got 1 solr instances with one core.</li>
  <li>My system works on a Virtual Machine with 8 CPUs and 16GB RAM</li>
  <li>I use around 30 % of RAM </li>
  <li>My JVM is : 1.7.0_09-icedtea
  OpenJDK Runtime Environment (rhel-2.3.8.0.el6_4-x86_64)
  OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)</li>
  </ul>
  
  <p><b>Questions</b></p>
  
  <ul>
  <li>Maybe I need to set more threads to update documents or something like that. </li>
  <li>Could this behaviour be related with Jetty ? (I don't think there is a link with Jetty, may someone could confirm it ?)</li>
  <li>How can I use more RAM to index data ? (I have allready set the JVM to allocate enough RAM for Solr with this command :  java -Xms2048M -Xmx8192M -jar start.jar)</li>
  <li>Should I use more solr instances (SolrCloud ?) to solve it ? </li>
  <li>Why Qtime increase with the update load ? Is it Solr limitations (RAM, Disk)? </li>
  </ul>
  
  <p>Any tips to help me to do the completion of my updates faster, would be appreciated. </p>
  
  <p>Thanks.</p>