gistfile1.pl

# Create
$self->helper( mdb => sub {
   my ( $self, $arg_ref ) = @_;

   my $pg = Mojo::Pg->new(
      "postgresql://$config->{db_host}/$config->{db_name}" );
   $pg->options({ RaiseError => 1 });
   $pg->username( $arg_ref->{db_user} );
   $pg->password( $arg_ref->{db_pass} );
   my $dbh = $pg->db;
   return $dbh;
});

# Elsewhere inside a sub:

warn "mdbh = ". Dumper( $mdbh );
my $query = <<"END_QUERY";
SELECT timestamp FROM quote_id( $agent_table )
ORDER BY timestamp desc LIMIT 1
END_QUERY

Mojo::IOLoop->delay(
   sub {
      my $delay = shift;
      warn "delay = $delay";
      warn "query = $query";
      $mdbh->query( $query => $delay->begin );
   },
   sub {
      my ($delay, $err, $results) = @_;
      $data = $results->arrays;
   }
)->wait;