Perl client using DBD:Pg hangs with resultset > 512 rows

#! /usr/bin/perl

use strict;
use warnings;
use DBI;



my $db_type = 'Pg';
my $db_name = 'EngVDBF';
my $db_host = 'vdb.engineering.redhat.com';
my $db_port = 35432;
my $user = 'teiid';
my $pass = 'teiid';
my $attr = { AutoCommit => 0, RaiseError => 1 };

my $dsn = sprintf( "dbi:%s:dbname=%s;host=%s;port=%s",
    $db_type, $db_name, $db_host, $db_port );

my $dbh = DBI->connect( $dsn, $user, $pass, $attr );

my $limit = ( $ARGV[0] ) ? "limit $ARGV[0]" : "";

my $query = <<QUERY;
    select bugs.bug_id, bugs.priority, bugs.bug_severity
      from BugzillaS.bugs bugs $limit
QUERY

my $sth = $dbh->prepare($query);
$sth->execute();

while ( my @row = $sth->fetchrow_array() ) {
    print join( ',', map {"\"$_\""} @row ) . "\n";
}

$sth->finish();
$dbh->disconnect();