At 16:01 22.06.2003 +0700, you wrote:

> 8: for k = 0 to result_set_record_count - 1 do
> 9: begin
>10: update one_table set one_field = a_value
> where match_conditions;
>11: commit retain;
>12: end;

The simple answer would be for you to change this bit of your pseudocode to

8: for k = 0 to result_set_record_count - 1 do
9: begin
10: update one_table set one_field = a_value
where match_conditions;
11: end;
12: commit;

Commit retain is not a proper commit, and committing for every record is
the reason for your slow updates. Your files will still grow past 4Mb, but
should grow a lot less than it currently does and you will not care since
your updates now happen in a matter of seconds, not minutes.

Set