[Q] Sequences, last_value and inserts

PostgreSQL 7.2.1
RHL 7.3
DBI, DBD::Pg

I'm inserting some values into a table with a serial field.  This is being
done using Perl and the DBI.  I then pull back using 'last_value' what I
hope is the value for the insert. The thought came to mind that if the
database is getting hit pretty hard there may be another access of the
sequence and last_value will be wrong 'for me'.
   Question is how do I insure I get the correct last-value?  Enclose in a
BEGIN/END block?  (How's that done using Perl? - my DBI book isn't at
hand).


TIA,
Rod
--
  "Open Source Software - Sometimes you get more than you paid for..."