L/Tcl function is first executed in a database session, or
        when an additional interpreter has to be created because a PL/Tcl
        function is called by a new SQL role.
       </p><p>
        The referenced function must be written in the <code class="literal">pltcl</code>
        language, and must not be marked <code class="literal">SECURITY DEFINER</code>.
        (These restrictions ensure that it runs in the interpreter it's
        supposed to initialize.)  The current user must have permiss