question

shouldn"t the connection method be the same with or without an account password?

when viewing the Memcached driver file of Yii2, it is found that a binary connection is made when there is an account password, otherwise a simple connection is made.

related

Yii2 version: 2.0.13
location: vendor/yiisoft/yii2/caching/MemCache.php:225

if ($this->useMemcached) {
    $this->_cache = $this->persistentId !== null ? new \Memcached($this->persistentId) : new \Memcached();
    if ($this->username !== null || $this->password !== null) {
        $this->_cache->setOption(\Memcached::OPT_BINARY_PROTOCOL, true);
        $this->_cache->setSaslAuthData($this->username, $this->password);
    }