#perl

AnyEvent + pg_async

#!/usr/bin/env perl

use Modern::Perl;

use DBI;
use DBD::Pg qw(:async);

use Coro;
use AnyEvent;
use Time::HiRes qw(time);

sub query($) {
  my $start = time;

  my $sql = shift;
  my $dbh = DBI->connect('dbi:Pg:host=10.0.1.120;dbname=postgres');
  my $sth = $dbh->prepare($sql, { pg_async => PG_ASYNC });
  $sth->execute;

  until ($dbh->pg_ready) {
    my $cb = rouse_cb;
    my $readable = AE::io ($dbh->{pg_socket}, 0, $cb);  # pg_socket is readable
    my $timeout = AE::timer (1, 0, $cb);                # or one second timeout
    rouse_wait($cb);
  }

  $sth->pg_result;

  printf "Query completed in %.5fs\n", time - $start;
}

my $start = time;

my @threads = (
  async { query 'SELECT pg_sleep(1)' },
  async { query 'SELECT pg_sleep(1)' },
  async { query 'SELECT pg_sleep(1)' },
);

$_->join for @threads;

printf "Program completed in %.5fs\n", time - $start;