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

On 05/11/2016 11:41 AM, Karsten Hilbert wrote:
> On Wed, May 11, 2016 at 11:17:54AM +0200, Niels Kristian Schjødt wrote:
>
>> We have an ssh connection running from one server to our
>> postgresql database on another server. Some times we
>> experience that the ssh tunnel does not work anymore and
>> needs to be restarted, even though we use the autossh
>> package. I would like to write a script that “pings”
>> postgresql on the specified port, to check if the connection
>> goes through. I have tried with netcat, but it does not
>> really check if postgresql is in the other end of the tunnel,
>> it only check if there is as service (the tunnel) listing on
>> the port on the local machine. Is there another way of
>> pinging the port, to see if postgresql is alive at the other
>> end? If possible, I would like to NOT actually establishing a
>> connection to postgresql like if i used psql -c “select 1;”,
>> to avoid connection overhead.
>
> This
>
>     http://www.postgresql.org/docs/devel/static/libpq-connect.html
>
> talks about ping functionality. Maybe you can use a tiny
> custom piece of code ?

That tiny custom piece of code would be this:

http://www.postgresql.org/docs/current/static/app-pg-isready.html

--
Vik Fearing                                          +33 6 46 75 15 36
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support