public function getLastActivityTimestamp($include_gc_admin = false)
 {
     if ($include_gc_admin) {
         $record = $this->selectFromMdlTable('log', null, null, true, 'time DESC');
     } else {
         if (!($gc_admin = $this->getGCAdminUser())) {
             global $CFG;
             $CFG->current_app->gcError("eSchool {$this->short_name}: No gcadminuser found.");
             $gc_admin = new stdClass();
             $gc_admin->id = -1;
         }
         $sql = 'select max(time) as time from ' . $this->short_name . '.mdl_log where userid != ? order by time DESC';
         $record = $this->gcQuery($sql, array($gc_admin->getObject()->id), true);
     }
     return $record->time;
 }