title: Spark 1.6: filtering DataFrames generated by describe()
body: <p>The problem arises when I call <code>describe</code> function on a DataFrame:</p>
  
  <pre class="lang-scala prettyprint-override"><code>val statsDF = myDataFrame.describe()
  </code></pre>
  
  <p>Calling describe function yields the following output:</p>
  
  <pre><code>statsDF: org.apache.spark.sql.DataFrame = [summary: string, count: string]
  </code></pre>
  
  <p>I can show <code>statsDF</code> normally by calling <code>statsDF.show()</code></p>
  
  <pre><code>+-------+------------------+
  |summary|             count|
  +-------+------------------+
  |  count|             53173|
  |   mean|104.76128862392568|
  | stddev|3577.8184333911513|
  |    min|                 1|
  |    max|            558407|
  +-------+------------------+
  </code></pre>
  
  <p>I would like now to get the standard deviation and the mean from <code>statsDF</code>, but when I am trying to collect the values by doing something like:</p>
  
  <pre class="lang-scala prettyprint-override"><code>val temp = statsDF.where($"summary" === "stddev").collect()
  </code></pre>
  
  <p>I am getting <code>Task not serializable</code> exception.</p>
  
  <p>I am also facing the same exception when I call:</p>
  
  <pre class="lang-scala prettyprint-override"><code>statsDF.where($"summary" === "stddev").show()
  </code></pre>
  
  <p>It looks like we cannot filter DataFrames generated by <code>describe()</code> function?</p>