memcached - PHP using memcache weights and consistent hashing not working

The weight of php calling memcahe is invalid

<code>PHP使用Memcached的扩展addServers使用权重，但是结果还是1:1，权重10:0,请问是什么原因呢？  
</code>

<code><?php
/**
 * 测试memcache一致性hash
 * 使用docker运行
 *
 * docker pull memcached
 * docker stop memcache-01
 * docker stop memcache-02
 * docker rm memcache-01
 * docker rm memcache-02
 * docker run --name memcache-01 -p 11201:11211 -d memcached
 * docker run --name memcache-02 -p 11202:11211 -d memcached
 */
$mem = new Memcached;
$mem->addServers(
    [
//        ['192.168.33.4',11201,10],
        ['192.168.33.4',11202,0]
    ]
);
//$mem->setOption(Memcached::OPT_DISTRIBUTION, Memcached::DISTRIBUTION_CONSISTENT);
//$mem->setOption(Memcached::OPT_HASH, Memcached::HASH_MD5);
for($i=0;$i<10000;$i++){
    $key = md5(uniqid($i.'_'));
    $mem->add($key,'1');
}
</code>

Reply content:

The weight of php calling memcahe is invalid

<code>PHP使用Memcached的扩展addServers使用权重，但是结果还是1:1，权重10:0,请问是什么原因呢？  
</code>

<code><?php
/**
 * 测试memcache一致性hash
 * 使用docker运行
 *
 * docker pull memcached
 * docker stop memcache-01
 * docker stop memcache-02
 * docker rm memcache-01
 * docker rm memcache-02
 * docker run --name memcache-01 -p 11201:11211 -d memcached
 * docker run --name memcache-02 -p 11202:11211 -d memcached
 */
$mem = new Memcached;
$mem->addServers(
    [
//        ['192.168.33.4',11201,10],
        ['192.168.33.4',11202,0]
    ]
);
//$mem->setOption(Memcached::OPT_DISTRIBUTION, Memcached::DISTRIBUTION_CONSISTENT);
//$mem->setOption(Memcached::OPT_HASH, Memcached::HASH_MD5);
for($i=0;$i<10000;$i++){
    $key = md5(uniqid($i.'_'));
    $mem->add($key,'1');
}
</code>

• Conclusion:

• 1 weight is only effective when using consistent hashing

• 2 OPT_LIBKETAMA_COMPATIBLE must be used for consistent hashing
  *

• Question: Two parameters must be effective at the same time, why do they need to be 2?