@Override
 protected Xowd_page_itm Get_page_or_null(Xowd_page_itm rdr_page) {
   Xow_ns ns = ns_mgr.Ids_get_or_null(rdr_page.Ns_id());
   if (ns == null)
     return null; // NOTE: ns seems to "randomly" be null when threading during redlinks; guard
                  // against null; DATE:2014-01-03
   byte[] ttl_wo_ns = rdr_page.Ttl_page_db();
   rdr_page.Ttl_(ns, ttl_wo_ns);
   return (Xowd_page_itm) hash.Get_by(rdr_page.Ttl_full_db());
 }