LOOP and EXIT

Hello,

I'm new here in this group... and I hope that I find the solution for my
problem here.

I wrote a simple function which looks like this:

CREATE OR REPLACE FUNCTION watchdog() RETURNS TIME AS '
DECLARE
watchdog_control RECORD;
help RECORD;
BEGIN
LOOP
PERFORM * FROM watchdog_ctl;

IF NOT FOUND THEN
EXIT;
END IF;

PERFORM sleep(3);

END LOOP;
RETURN now();
END;
' LANGUAGE plpgsql;

That means that I want to leave the loop if there isn't an entry in the
table watchdog_ctl. This works fine if the table is empty at the startup of
the function (select watchdog();). But if I empty the table watchdog_ctl
while the function is running it seems to be an endless loop. Hay anyone of
you an idea why??

Many thanks!

Sebastian