Solution : https://service.sap.com/sap/support/notes/1419451 (SAP Service marketplace login required)
Key words : 
textb_date   delete bookmarks older thanb_id   delete bookmark idb_type   delete bookmark typeb_user   delete bookmarks owned bydate, bookmark deletion tty   bookmark type based selection tur   owner based selection 2, tbk   direct bookmark input tdt   date based selection tsl   selections, ondate_u   delete bookmarks older thanp_type   bookmark types_id   bookmark id, s_tmpl   web templates_tmpl_d  web templates_tmpl_u  web templates_usr   user name3, function code        delete          function text        delete          icon, title number         titleselected bookmarks   selected bookmarks, software component   sap_bw                        business inform, manual post-implementation step manually, text           delete chosen bookmarks5
Related Notes : 
       
| 1446964 | RSWR_BOOKMARK_DELETE: Performance optimization | 
| 1408383 | BEx Web 7.0: Improvements in Bookmark Maintenance | 
| 1407600 | SAPBWNews NW BW 7.02 ABAP SP03 | 
| 1407599 | Preliminary Version SAPBWNews NW BW 7.20 ABAP SP03 | 
| 1407598 | SAPBWNews NW BW 7.0 ABAP SP 24 | 
| 1392433 | SAPBINews NW7.11 BW ABAP Support Package 05 | 
| 1369294 | SAPBINews NW7.01 BW ABAP Support Package 07 | 
| 706478 | Preventing Basis tables from increasing considerably |