_fdw</code> allows
       foreign tables to be scanned concurrently for asynchronous execution.
       It can be specified for a foreign table or a foreign server.
       A table-level option overrides a server-level option.
       The default is <code class="literal">false</code>.
      </p><p>
       In order to ensure that the data being returned from a foreign server
       is consistent, <code class="filename">postgres_fdw</code> will only open one
       connection for a given foreign server and will 