watchdog_overview() is terribly slow

Ever tried to browse admin/logs with 586 891 records in the watchdog table? It takes in average about 13.9692559242 seconds on my server. I think it is important to get it lower because everytime you click on "administer" you get that watchdog overview.

My concern is about the watchdog_overview() function and especially about this code

  $header = array(
    ' ',
    array('data' => t('Type'), 'field' => 'w.type'),
    array('data' => t('Date'), 'field' => 'w.wid', 'sort' => 'desc'),
    array('data' => t('Message'), 'field' => 'w.message'),
    array('data' => t('User'), 'field' => 'u.name'),
    array('data' => t('Operations'))
  );

  $sql = "SELECT w.*, u.name, u.uid FROM {watchdog} w INNER JOIN {users} u ON w.uid = u.uid";
  $tablesort = tablesort_sql($header);
  $type = $_SESSION['watchdog_overview_filter'];
  if ($type != 'all') {
    $result = pager_query($sql ." WHERE w.type = '%s'". $tablesort, 50, 0, NULL, $type);
  }
  else {
    $result = pager_query($sql . $tablesort, 50);
  }

  while ($watchdog = db_fetch_object($result)) {
    $rows[] = array('data' =>
      array(
        // Cells
        $icons[$watchdog->severity],
        t($watchdog->type),
        format_date($watchdog->timestamp, 'small'),
        l(truncate_utf8($watchdog->message, 56, TRUE, TRUE), 'admin/logs/event/'. $watchdog->wid, array(), NULL, NULL, FALSE, TRUE),
        theme('username', $watchdog),
        $watchdog->link,
      ),
      // Attributes for tr
      'class' => "watchdog-". preg_replace('/[^a-z]/i', '-', $watchdog->type) .' '. $classes[$watchdog->severity]
    );
  }

I tried to optimize the SQL query but had no luck.
So here is one solution to bring it down to a generation time of 0.0609180927275 seconds -- but it does not provide the same functionality because the sorting by username is lost.

  // CHANGE: Sorting by username disabled
  $header = array(
    ' ',
    array('data' => t('Type'), 'field' => 'type'),
    array('data' => t('Date'), 'field' => 'wid', 'sort' => 'desc'),
    array('data' => t('Message'), 'field' => 'message'),
    array('data' => t('User'), /*'field' => 'u.name'*/),
    array('data' => t('Operations'))
  );

  // CHANGE: Fetch users seperately
  $result = db_query("SELECT uid, name FROM {users}");
  while ( $user = db_fetch_object($result) ) {
    $users[$user->uid] = $user;
  }

  // CHANGE: Replacing with this simple and fast SELECT
  //$sql = "SELECT w.*, u.name, u.uid FROM {watchdog} w INNER JOIN {users} u ON w.uid = u.uid";
  $sql = "SELECT * FROM {watchdog}";
  $tablesort = tablesort_sql($header);
  $type = $_SESSION['watchdog_overview_filter'];
  if ($type != 'all') {
    $result = pager_query($sql ." WHERE type = '%s'". $tablesort, 50, 0, NULL, $type);
  }
  else {
    $result = pager_query($sql . $tablesort, 50);
  }

  while ($watchdog = db_fetch_object($result)) {
    $rows[] = array('data' =>
      array(
        // Cells
        $icons[$watchdog->severity],
        t($watchdog->type),
        format_date($watchdog->timestamp, 'small'),
        l(truncate_utf8($watchdog->message, 56, TRUE, TRUE), 'admin/logs/event/'. $watchdog->wid, array(), NULL, NULL, FALSE, TRUE),
        // CHANGE: Format the username
        //theme('username', $watchdog),
        theme('username', $users[$watchdog->uid]),
        $watchdog->link,
      ),
      // Attributes for tr
      'class' => "watchdog-". preg_replace('/[^a-z]/i', '-', $watchdog->type) .' '. $classes[$watchdog->severity]
    );
  }

Any suggestions? Other ideas?