title: What is the use of queryExecution in spark dataframe?
body: <p>I have got to know about variable called queryExecution on a dataframe object and found below output in console . But it is not sure how it can be helpful .Please find the output in the console.</p>
  
  <pre><code>scala&gt; df.queryExecution
  res5: org.apache.spark.sql.SQLContext#QueryExecution =
  == Parsed Logical Plan ==
  Project [_1#0 AS ID#2,_2#1 AS Token4#3]
   LocalRelation [_1#0,_2#1], [[1,a],[2,b]]
  
  == Analyzed Logical Plan ==
  ID: int, Token4: string
  Project [_1#0 AS ID#2,_2#1 AS Token4#3]
   LocalRelation [_1#0,_2#1], [[1,a],[2,b]]
  
  == Optimized Logical Plan ==
  LocalRelation [ID#2,Token4#3], [[1,a],[2,b]]
  
  == Physical Plan ==
  LocalTableScan [ID#2,Token4#3], [[1,a],[2,b]]
  
  Code Generation: true
  </code></pre>
  
  <p>Thanks</p>