... 
my $count = $sth->execute or die;
my $total = 0;
while (my $rows = $sth->fetchall_arrayref([0], 3)) {
die "Error: $DBI::errstr" if $DBI::err; # error different
                                                 # to 'end of while'
for (@$rows) {
    print "got @$_\n";
 }
  print "---\n";
$total += scalar @$rows;
last if $total == $count;
}