title: where does df.cache() is stored
body: <p>I would like to understand in which node (driver or worker/executor) does below code is stored</p>
  
  <pre><code>df.cache() //df is a large dataframe (200GB)
  </code></pre>
  
  <p>And which has a better performance: using sql <code>cachetable</code> or <code>cache()</code>. My understanding is that one of them is lazy and the other is eager.</p>