By default, a file watcher checks for new file arrivals every 10 minutes.
In order to use file watchers, the database Java Virtual Machine (JVM) component must be installed.
Change the default exection interval
Change the default execution interval to one minute:
begin
dbms_scheduler.set_attribute(
'file_watcher_schedule',
'repeat_interval',
'freq=minutely; interval=1'
);
end;
/