Logging duration of batch runs

Hi,

I have a stored procedure run periodically that assign accounting records
to their respective customers based on username and other criteria.
It also does all kinds of validation work on the accounting records.

I would have liked to have the procedure log start and stop times
using RAISE NOTICE and also store start and stop time of each run
to a logging table.

I currently have following:

---snipp---
CREATE OR REPLACE FUNCTION radius.radius_acct_batch() RETURNS void
     AS '
DECLARE
         batch_id int;
         realm RECORD;
         start_time timestamp;
         stop_time timestamp;
BEGIN
         -- start new batch
         start_time := ''now'';
         INSERT INTO radius.radius_acct_batch ( radius_acct_batch_run_start ) VALUES ( start_time );
         SELECT INTO batch_id currval(''radius.radius_acct_batch_radius_acct_batch_id_seq'');

         RAISE NOTICE ''radius.radius_acct_batch, radius_acct_batch_id=%, start_time=%.'', batch_id, start_time;

         -- do actual work

     ...
     ...
     ...
     ...


         -- register end date in batch
         stop_time := ''now'';
         UPDATE radius.radius_acct_batch SET radius_acct_batch_run_end=stop_time WHERE radius_acct_batch_id=batch_id;
         RAISE NOTICE ''radius.radius_acct_batch, radius_acct_batch_id=%, stop_time=%, done.'', batch_id, stop_time;

         RETURN;
END'
     LANGUAGE plpgsql;
---snipp---

the problem is that start_time and stop_time are identical.

Is there any way I can get plpgsql to reevaluate now at the end
of the batch ???

Greetings
Christian

--
Christian Kratzer                       ck@cksoft.de
CK Software GmbH                        http://www.cksoft.de/
Phone: +49 7452 889 135                 Fax: +49 7452 889 136