">SELECT</code>, <code class="command">UPDATE</code>,
  <code class="command">DELETE</code> or <code class="command">TRUNCATE</code>
  has no effect when accessing or modifying the remote table.
 </p><p>
  Note that <code class="filename">postgres_fdw</code> currently lacks support for
  <code class="command">INSERT</code> statements with an <code class="literal">ON CONFLICT DO
  UPDATE</code> clause.  However, the <code class="literal">ON CONFLICT DO NOTHING</code>
  clause is supported, provided a unique 