TTT (220)
    Primary pointer page: 147377, Index root page: 147424
    Total formats: 1, used formats: 1
    Average record length: 9.00, total records: 100000
    Average version length: 0.00, total versions: 0, max versions: 0
    Average fragment length: 0.00, total fragments: 0, max fragments: 0
    Average unpacked length: 8.00, compression ratio: 0.89
    Pointer pages: 1, data page slots: 614
    Data pages: 614, average fill: 52%
    Primary pages: 614, full pages: 0, swept pages: 0
    Fill distribution:
         0 - 19% = 0
        20 - 39% = 1
        40 - 59% = 613
        60 - 79% = 0
        80 - 99% = 0

    Index RDB$PRIMARY4 (0)
        Root page: 10003, depth: 2, leaf buckets: 85, nodes: 100000
        Average node length: 4.99, total dup: 0, max dup: 0
        Average key length: 3.00, compression ratio: 1.26
        Average prefix length: 2.77, average data length: 1.00
        Clustering factor: 99815, ratio: 1.00
        Fill distribution:
             0 - 19% = 0
            20 - 39% = 0
            40 - 59% = 40
            60 - 79% = 2
            80 - 99% = 43

set term ^;
execute block as
  declare a int;
  declare b int;
  declare c cursor for ( select id from ttt where id between :a and :b order by id ) ;
  declare id int;
begin
  a = 0;
  b = 100000;
  open c;
  while(1=1) do begin
     fetch c into id;
     if ( row_count = 0 ) then leave;
      update ttt set id=id where current of c; 
  end
  close c;
end
^
set term ;^
commit;

set term ^;
execute block as
  declare a int;
  declare b int;
begin
  a = 0;
  b = 100000;
  for select id from ttt where id between :a and :b order by id  as cursor c
  do begin
     update ttt set id=id where current of c;
  end
end
^
set term ;^
commit;

set term ^;
execute block as
  declare a int;
  declare b int;
  declare dbkey char(8) character set octets;
  declare id int;
begin
  a = 0;
  b = 100000;
  for
      select rdb$db_key from ttt where id between :a and :b  order by id 
      into dbkey
  do begin
     update ttt set id=id where rdb$db_key = :dbkey;
  end
end
^
set term ;^
commit;

set term ^;
execute block as
  declare a int;
  declare b int;
  declare dbkey char(8) character set octets;
  declare id int;
begin
  a = 0;
  b = 1000000;
  for
      select rdb$db_key from ttt where id between :a and :b  order by id 
      into dbkey
  do begin
     select id from ttt where rdb$db_key = :dbkey for update with lock into id;
  end
end
^
set term ;^
commit;