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