ALTER SEQUENCE GEN_VERSION RESTART WITH 21060100;

select gen_id(GEN_VERSION, 0) from rdb$database

create or alter procedure TEST (
    N integer,
    V integer)
as
declare variable nums varchar(16) = '[-+]?[0-9]{1,10}';
declare variable b boolean;
begin
  while (n > 0) do
  begin
    if (v = 1) then
      b = '5' similar to nums;
    else if (v = 2) then
      b = '5' similar to '[-+]?[0-9]{1,10}';
    n = n - 1;
  end
end

execute procedure test(1000000, 1)

execute procedure test(1000000, 2)

CREATE SEQUENCE GEN_VERSION START WITH 21000000 INCREMENT BY 1;

ALTER SEQUENCE GEN_VERSION RESTART WITH 21060100;

select rdb$initial_value from rdb$generators where rdb$generator_name = 'GEN_VERSION'

select gen_id(gen_version, 0) from rdb$database