 class="literal">all</code> specifies that it
       matches all users.  Otherwise, this is either the name of a specific
       database user, a regular expression (when starting with a slash
       (<code class="literal">/</code>), or a group name preceded by <code class="literal">+</code>.
       (Recall that there is no real distinction between users and groups
       in <span class="productname">PostgreSQL</span>; a <code class="literal">+</code> mark really means
       <span class="quote">“<span cl