> There is no such concept, at present. See the archives...
Then why does this work?:
australia=# select current_timestamp; timestamp
------------------------2002-02-15 12:03:35+08
(1 row)
australia=# select current_timestamp; timestamp
------------------------2002-02-15 12:03:36+08
(1 row)
australia=# select current_timestamp; timestamp
------------------------2002-02-15 12:03:37+08
(1 row)
australia=# select current_timestamp; timestamp
------------------------2002-02-15 12:03:38+08
(1 row)
australia=# begin transaction;
BEGIN
australia=# select current_timestamp; timestamp
------------------------2002-02-15 12:03:43+08
(1 row)
australia=# select current_timestamp; timestamp
------------------------2002-02-15 12:03:43+08
(1 row)
australia=# select current_timestamp; timestamp
------------------------2002-02-15 12:03:43+08
(1 row)
australia=# select current_timestamp; timestamp
------------------------2002-02-15 12:03:43+08
(1 row)