title: Is Spark zipWithIndex safe with parallel implementation?
body: <p>If I have a file, and I did an RDD zipWithIndex per row, </p>
  
  <pre><code>([row1, id1001, name, address], 0)
  ([row2, id1001, name, address], 1)
  ...
  ([row100000, id1001, name, address], 100000)
  </code></pre>
  
  <p>Will I be able to get the same index order if I reload the file? Since it runs in parallel, other rows may be partitioned differently?</p>