Codeigniter $ this-> cache-> memcached-> save（'foo'，'bar'，600）返回false

I'm testing memcached on Codeigniter 3.1.2 using MAMP. I have memcached showing on my phpinfo page (version: 2.2.0)

Below is my code.

//In the /Application/config/memcached.php file

$config = array(
    'default' => array(
        'hostname' => 'new-app.dev',
        'port' => '11211',
        'weight' => '1',
    ),
);

.

public function test_caching() {
    $this->load->driver('cache');
    var_dump($this->cache->memcached->save('foo', 'bar', 600)); // Returns false
}

The code below returns:

echo '<pre>';
print_r($this->cache->memcached->cache_info());

Array
(
    [new-app.dev:11211] => Array
        (
            [pid] => -1
            [uptime] => 0
            [threads] => 0
            [time] => 0
            [pointer_size] => 0
            [rusage_user_seconds] => 0
            [rusage_user_microseconds] => 0
            [rusage_system_seconds] => 0
            [rusage_system_microseconds] => 0
            [curr_items] => 0
            [total_items] => 0
            [limit_maxbytes] => 0
            [curr_connections] => 0
            [total_connections] => 0
            [connection_structures] => 0
            [bytes] => 0
            [cmd_get] => 0
            [cmd_set] => 0
            [get_hits] => 0
            [get_misses] => 0
            [evictions] => 0
            [bytes_read] => 0
            [bytes_written] => 0
            [version] => 
        )

)

SSL is installed on new-app.dev. Could someone please tell me what I'm missing?

Looking at uptime and pid, it looks like you did not install memcache server or it is not running. Memcache is not a part of MAMP you need to install that separately

To install Memcache server on mac simply run brew install memcached

Memcache server and Memcache php Drivers are two entirely separate things