Lightest way of checking if postgresql is running at the other end of an ssh tunnel?

Hi,

We have an ssh connection running from one server to our postgresql database on another server. Some times we
experiencethat the ssh tunnel does not work anymore and needs to be restarted, even though we use the autossh package.
Iwould like to write a script that “pings” postgresql on the specified port, to check if the connection goes through. I
havetried with netcat, but it does not really check if postgresql is in the other end of the tunnel, it only check if
thereis as service (the tunnel) listing on the port on the local machine. Is there another way of pinging the port, to
seeif postgresql is alive at the other end? If possible, I would like to NOT actually establishing a connection to
postgresqllike if i used psql -c “select 1;”, to avoid connection overhead. 

Any ideas?