title: JMeter - Graphite Backend listener rootmetricsPrefix taking previously generated value
body: <p><strong>Background</strong>:
  I am using graphite to store the data generated during the performance test and ideally, we would like to look at the historical graphs as well. Hence, I am creating a rootMetricsPrefix folder name dynamically in a setup thread group and assigning it to a property. The backend listener is in a different thread group and the configuration uses this folder name as the rootMetricsPrefix - </p>
  
  <pre><code>&lt;elementProp name="rootMetricsPrefix" elementType="Argument"&gt;
                  &lt;stringProp name="Argument.name"&gt;rootMetricsPrefix&lt;/stringProp&gt;
                  &lt;stringProp `enter code here`name="Argument.value"&gt;${__property(graphiteFolderName)}&lt;/stringProp&gt;
                  &lt;stringProp name="Argument.metadata"&gt;=&lt;/stringProp&gt;
  &lt;/elementProp&gt;
  </code></pre>
  
  <p><strong>Symptoms</strong>:
  The first time the JMeter srcript is run (after opening JMeter), no folder is generated in the Graphite DB. From the second run onwards, results are written to a folder which was defined in the previous run. For example,
  Run 1: DynamicResultsFolder_1  (No Results written)
  Run 2: DynamicResultsFolder_2 (Results written to DynamicResultsFolder_1)
  Run 3: DynamicResultsFolder_3 (Results written to DynamicResultsFolder_2)</p>
  
  <p>When I print the folder name to the log in the main thread group, the expected folder name is printed out. The issue seems to be in the way the ${__property(graphiteFolderName)} is evaluated in the BackendListener configuration. </p>
  
  <p>I have also tried assigning the the property to a local variable and using the local variable in the BackendListener config, but that does not write any results to the DB.</p>
  
  <p>Any ideas as to what is going on here or if I am missing something obvious?</p>