name">postgres_fdw</code> supports asynchronous execution, which
    runs multiple parts of an <code class="structname">Append</code> node
    concurrently rather than serially to improve performance.
    This execution can be controlled using the following option:
   </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">async_capable</code> (<code class="type">boolean</code>)</span></dt><dd><p>
       This option controls whether <code class="filename">postgres