title: Build project periodically only if changes are found in the repository
body: <p>I have the following setup active and working:</p>
  
  <ul>
  <li>Jenkins with Git and Sonar plugins</li>
  <li>One jenkins job ( <code>project</code> ) which polls Git each minute</li>
  <li>One jenkins job ( <code>project-sonar</code> ) which polls git each 24 hours</li>
  </ul>
  
  <p>Both jobs share the same git repository.</p>
  
  <p>This allows me to build my project for each commit and then each day, only if the project has changed, run the Sonar analysis.</p>
  
  <p>I've recently set up the git repository to send notifications to Jenkins when a project has changed, as per <a href="https://wiki.jenkins-ci.org/display/JENKINS/Git+Plugin#GitPlugin-Pushnotificationfromrepository" rel="noreferrer">Push notifications from repository</a> . This builds both projects immediately, but I want only the quick ( <code>project</code> ) job to build. If I move the <code>project-sonar</code> to be built periodically, the sonar analysis will be run even if there are no code changes, which is wasteful.</p>
  
  <p>How can I retain</p>
  
  <ul>
  <li>immediate build for the <code>project</code> build</li>
  <li>daily build for for <code>project-sonar</code> build</li>
  </ul>
  
  <p>?</p>