It does not get mail for a long time. ;^)
It also can not establish a connection to the listener.
If you are on the same machine as the db, you could check
to see if the process is running. You could also setup
an inetd listener that indicates the status of the
postmaster. I have not done that in a long time, but
should be fairly simple and using tcpwrappers you can
make it reasonably safe.