python cgi problem

[etienne]

hi there !

I'm programming such a cgi:
step 1- user submits some data
step 2- cgi validates data
step 3- outputs a html file telling the user to wich url point to find
output
step 4- do the hard work.

the reason for step 3 is that step 4 needs to dig in a very large
database, and may take lot of time

everything woks fine but output of step3 comes when step 4 is over and
user needs to wait up to some minutes for his response.

cgi schema is as follow:

def main():
   # 2 
   params = validate_params()
   # 3 
   htm_out  = generate_output()
   print htm_out
   # 4
   os.system(" python my_module.py params &")


I can see results of   print htm_out when os.system(" python
my_module.py params &") is over

can i force htm_out output somehow ???

any suggestion
tnxs in advance
etienne