How to check if PGSQL server is still alive with DBD::PG?

Question

I am desperately trying to find an easy way to regulary check if a PGSQL server is still alive from within a perl script. I intended to use pg_ping for this, but in my tests pg_ping always returns 1, independently of the DB server status.

Here's the code I tried it with:

#!/usr/bin/perl
use strict;
use warnings;
use DBD::Pg;

my $dbh=DBI->connect("DBI:Pg:dbname=healthcheck;host=vm0484","healthcheck","areyoustillthere");
for (my $i=1;$i<100;$i++) {
print "$i. pg_ping: ".$dbh->pg_ping."\n";
sleep(1);
}

I then used kill -9 in another window to manually terminate the PGSQL-server, but the result was still 1. Did I do something wrong?

If not, how do I best check, if the DB server is still alive?

Thanks in advance.

Answer 1

You can manually perform query like

select 1 as is_alive

as ping() also claim to do something similar,

The ping method issues an empty query and checks the result status.