Calling now() in a function - postgresql

Question

One of our Postgres tables, called rep_event, has a timestamp column that indicates when each row was inserted. But all of the rows have a timestamp value of 2000-01-01 00:00:00, so something isn't set up right.
There is a function that inserts rows into the table, and it is the only code that inserts rows into that table - no other code inserts into that table. (There also isn't any code that updates the rows in that table.) Here is the definition of the function:
CREATE FUNCTION handle_event() RETURNS "trigger"
AS $$
BEGIN
IF (TG_OP = 'DELETE') THEN
INSERT INTO rep_event SELECT 'D', TG_RELNAME, OLD.object_id, now();
RETURN OLD;
ELSIF (TG_OP = 'UPDATE') THEN
INSERT INTO rep_event SELECT 'U', TG_RELNAME, NEW.object_id, now();
RETURN NEW;
ELSIF (TG_OP = 'INSERT') THEN
INSERT INTO rep_event SELECT 'I', TG_RELNAME, NEW.object_id, now();
RETURN NEW;
END IF;
RETURN NULL;
END;
$$ LANGUAGE plpgsql;
Here is the table definition:
CREATE TABLE rep_event
(
operation character(1) NOT NULL,
table_name text NOT NULL,
object_id bigint NOT NULL,
time_stamp timestamp without time zone NOT NULL
)
As you can see, the now() function is called to get the current time. Doing a "select now()" on the database returns the correct time, so is there an issue with calling now() from within a function?

Answer 1

A simpler solution is to just modify your table definition to have NOW() be the default value:
CREATE TABLE rep_event (
operation character(1) NOT NULL,
table_name text NOT NULL,
object_id bigint NOT NULL,
time_stamp timestamp without time zone NOT NULL DEFAULT NOW()
);
Then you can get rid of the now() calls in your trigger.
Also as a side note, I strongly suggest including the column ordering in your function... IOW;
INSERT INTO rep_event (operation,table_name,object_id,time_stamp) SELECT ...
This way if you ever add a new column or make other table changes that change the internal ordering of the tables, your function won't suddenly break.

Answer 2

Your problem has to be elsewhere, as your function works well. Create test database, paste the code you cited and run:
create table events (object_id bigserial, data text);
create trigger rep_event
before insert or update or delete on events
for each row execute procedure handle_event();
insert into events (data) values ('v1'),('v2'),('v3');
delete from events where data='v2';
update events set data='v4' where data='v3';
select * from events;
object_id | data
-----------+------
1 | v1
3 | v4
select * from rep_event;
operation | table_name | object_id | time_stamp
-----------+------------+-----------+----------------------------
I | events | 1 | 2011-07-08 10:31:50.489947
I | events | 2 | 2011-07-08 10:31:50.489947
I | events | 3 | 2011-07-08 10:31:50.489947
D | events | 2 | 2011-07-08 10:32:12.65699
U | events | 3 | 2011-07-08 10:32:33.662936
(5 rows)
Check other triggers, trigger creation command etc. And change this timestamp without timezone to timestamp with timezone.