title: How to manage Presto query session variables using REST API?
body: <p>I am using the Presto REST api to query the database, but all my sessions appear to be ephemeral. For example, if I do something like</p>
  
  <p><code>
  query_presto('set session columnar_processing = true')
  query_presto('show session')
  </code></p>
  
  <p>Despite setting the column_processing variable in the first query, the second query will show that column_processing is still the default value of false.</p>
  
  <p>I read somewhere that </p>
  
  <blockquote>
    <p>Presto maintains sessions for each authenticated user. This session
    expires if no new requests are received within the timeout period
    configured for Presto.</p>
  </blockquote>
  
  <p>However, I can't find this configuration anywhere in the code nor documentation.</p>
  
  <p>My question is how do I maintain a database session using the RESTful API?</p>