use strict; use warnings; use feature 'say';
use Data::Dumper;

use MCE::Shared;

my $db = MCE::Shared->minidb();

my %hash = ( problem => 'foo', technique => 'blorgle', answer => 41 );
my %junk = ( problem => 'bla', technique => 'blargle' );

$db->hset( my_key => %hash );
$db->hset( junkey => %junk ); # sorry for the bad pun

my $pid = fork;
die 'Fork failed' if not defined $pid;

if ( $pid == 0 ) { # child
    $db->happend( my_key => (problem => 'bar'));
    $db->hincr( my_key => 'answer');
    $db->hset( my_key => (technique => 'frobnicate') );
    exit;
}

# parent
wait;

my @rows = $db->select_href(':hashes', ':WHERE answer > 0');

say Dumper \@rows;

__END__

##</code><code>##

$ perl monks/1226220.pl

$VAR1 = [
          [
            'my_key',
            {
              'answer' => 42,
              'problem' => 'foobar',
              'technique' => 'frobnicate'
            }
          ]
        ];