declare
   error_1578 exception;
   pragma exception_init(error_1578,-1578);
   n number;
   cnt number:=0;
   badcnt number:=0;
  begin
    for cursor_lob in
          (select rowid r, &LOB_COLUMN_NAME L from &OWNER..&TABLE_NAME)
    loop
      begin
        n:=dbms_lob.instr(cursor_lob.L,hextoraw('AA25889911'),1,999999) ;
      exception
       when error_1578 then
         dbms_output.put_line('Got ORA-1578 reading LOB at '||cursor_lob.R);
         badcnt:=badcnt+1;
      end;
      cnt:=cnt+1;
    end loop;
    dbms_output.put_line('Scanned '||cnt||' rows - saw '||badcnt||' errors');
  end;