public void Special__gen(Xoa_app app, Xow_wiki wiki, Xoa_page page, Xoa_url url, Xoa_ttl ttl) {
   int slash_pos =
       Bry_find_.Find_fwd(ttl.Page_txt_wo_qargs(), Xoa_ttl.Subpage_spr); // check for slash
   byte[] special_name =
       slash_pos == Bry_find_.Not_found
           ? ttl
               .Base_txt_wo_qarg() // no slash found; use base_txt; ignore qry args and just get
                                   // page_names; EX: Search/Earth?fulltext=y;
                                   // Allpages?from=Earth...
           : Bry_.Mid(
               ttl.Page_txt_wo_qargs(),
               0,
               slash_pos); // slash found; use root page; EX: Special:ItemByTitle/enwiki/Earth
   special_name =
       Xoa_ttl.Replace_spaces(special_name); // handle spaces; EX:Spezial:Zufällige_Seite
   Xow_special_page special = (Xow_special_page) hash.Get_by_bry(special_name);
   if (special != null) { // special found; generate it;
     special = special.Special__clone();
     page.Db().Page().Modified_on_(Datetime_now.Get());
     try {
       special.Special__gen(wiki, page, url, ttl);
     } catch (Exception e) {
       Gfo_log_.Instance.Warn(
           "failed to generate special page",
           "url",
           url.To_str(),
           "err",
           Err_.Message_gplx_log(e));
     }
   }
 }
 @Override
 public void Cmd_run() {
   wiki.Init_by_wiki();
   Xow_db_file core_db = wiki.Data__core_mgr().Db__core();
   Db_conn core_db_conn = core_db.Conn();
   Gfo_usr_dlg usr_dlg = Gfo_usr_dlg_.Instance;
   usr_dlg.Plog_many("", "", "creating page_filter");
   if (!core_db_conn.Meta_tbl_exists("page_filter")) {
     core_db_conn.Meta_tbl_create(
         Dbmeta_tbl_itm.New(
             "page_filter",
             new Dbmeta_fld_itm[] {
               Dbmeta_fld_itm.new_int("page_id").Primary_y_(),
               Dbmeta_fld_itm.new_int("page_text_db_id")
             },
             Dbmeta_idx_itm.new_normal_by_tbl(
                 "page_filter", "db_id__page", "page_text_db_id", "page_id"),
             Dbmeta_idx_itm.new_normal_by_tbl("page_filter", "page_id", "page_id")));
   }
   core_db_conn.Exec_sql_plog_ntx(
       "finding missing redirects",
       String_.Concat_lines_nl_skip_last(
           "INSERT INTO page_filter (page_id, page_text_db_id)",
           "SELECT  ptr.page_id, ptr.page_text_db_id",
           "FROM    page ptr",
           "        LEFT JOIN page orig ON ptr.page_redirect_id = orig.page_id",
           "WHERE   ptr.page_is_redirect = 1",
           "AND     orig.page_id IS NULL",
           "UNION",
           "SELECT  ptr.page_id, ptr.page_text_db_id",
           "FROM    page ptr",
           "WHERE   ptr.page_is_redirect = 1",
           "AND     ptr.page_redirect_id = -1",
           ";"));
   try {
     Xow_db_file[] db_file_ary =
         core_db.Tbl__db().Select_all(wiki.Data__core_mgr().Props(), wiki.Fsys_mgr().Root_dir());
     int len = db_file_ary.length;
     for (int i = 0; i < len; ++i) {
       boolean db_file_is_text = Bool_.N, db_file_is_cat = Bool_.N, db_file_is_search = Bool_.N;
       Xow_db_file db_file = db_file_ary[i];
       switch (db_file.Tid()) {
         case Xow_db_file_.Tid__core:
         case Xow_db_file_.Tid__wiki_solo:
         case Xow_db_file_.Tid__text_solo:
           if (wiki.Data__core_mgr().Props().Layout_text().Tid_is_lot())
             continue; // if mode is lot, then "core" db does not have text, cat, search; skip;
           // DATE:2016-01-31
           db_file_is_text = db_file_is_cat = db_file_is_search = Bool_.Y;
           break;
         case Xow_db_file_.Tid__text:
           db_file_is_text = Bool_.Y;
           break;
         case Xow_db_file_.Tid__cat:
           db_file_is_cat = Bool_.Y;
           break;
         case Xow_db_file_.Tid__search_core:
           db_file_is_search = Bool_.Y;
           break;
       }
       int db_id = db_file.Id();
       if (db_file_is_text)
         Run_sql(
             core_db_conn,
             db_file.Url(),
             db_id,
             "deleting text: " + db_id,
             "DELETE FROM <data_db>text WHERE page_id IN (SELECT page_id FROM page_filter WHERE page_text_db_id = {0});");
       if (db_file_is_cat)
         Run_sql(
             core_db_conn,
             db_file.Url(),
             db_id,
             "deleting cat: " + db_id,
             "DELETE FROM <data_db>cat_link WHERE cl_from IN (SELECT page_id FROM page_filter);");
       if (db_file_is_search)
         Run_sql(
             core_db_conn,
             db_file.Url(),
             db_id,
             "deleting search:" + db_id,
             "DELETE FROM <data_db>search_link WHERE page_id IN (SELECT page_id FROM page_filter);");
       if (db_file_is_text || db_file_is_cat || db_file_is_search) db_file.Conn().Env_vacuum();
     }
   } catch (Exception e) {
     Gfo_usr_dlg_.Instance.Warn_many(
         "", "", "fatal error during page deletion: err=~{0}", Err_.Message_gplx_log(e));
   }
   core_db_conn.Exec_sql_plog_ntx(
       "deleting from table: page",
       "DELETE FROM page WHERE page_id IN (SELECT page_id FROM page_filter);");
   // core_db_conn.Meta_tbl_delete("page_filter");
   core_db_conn.Env_vacuum();
   usr_dlg.Plog_many("", "", "");
 }