my $ary_ref;
my $hash_ref;
my $ary_out;
my $hash_out;

   timethese( 1_000, { 
    array_way => sub { 
          if (!$ary_ref) {
            $ary_ref  = $dbh->selectall_arrayref($statement);
            $ary_out = show_all_except($ary_ref,[0]);
          };
          print $ary_out;
          },
    hash_way  => sub { 
          if (!$hash_ref) {
            $hash_ref = $dbh->selectall_hashref($statement, $key_field);
            $hash_out = show_these($hash_ref,[ 'field1','field2','field3'  ]);
          };
          print $hash_out;
          }
            } );