PHP取模hash和一致性hash操作Memcached分布式集群-php教程

/usr/local/memcached/bin/memcached -d -p 11211 -u memcached -vv >> /var/log/memcached.11211.log 2>&1
/usr/local/memcached/bin/memcached -d -p 11212 -u memcached -vv >> /var/log/memcached.11212.log 2>&1
/usr/local/memcached/bin/memcached -d -p 11213 -u memcached -vv >> /var/log/memcached.11213.log 2>&1
/usr/local/memcached/bin/memcached -d -p 11214 -u memcached -vv >> /var/log/memcached.11214.log 2>&1

2.取模hash算法

php代码

<?php
/**
 * Created by PhpStorm.
 * User: jmsite.cn
 * Date: 2019/1/28
 * Time: 11:38
 */
$memcached = new Memcached();
//设置算法为取模hash
$memcached->setOptions(
    array(
        Memcached::OPT_DISTRIBUTION         => Memcached::DISTRIBUTION_MODULA,
        //Memcached::OPT_LIBKETAMA_COMPATIBLE => true,
        Memcached::OPT_REMOVE_FAILED_SERVERS=> true,
    )
);
//增加效劳器
$memcached->addServer('192.168.75.132', '11211');
$memcached->addServer('192.168.75.132', '11212');
$memcached->addServer('192.168.75.132', '11213');
$memcached->addServer('192.168.75.132', '11214');
//写入12个key
for ($i =1;$i <= 12;$i++){
    $memcached->set('key_'.$i, 'value_'.$i);
}

执行上述代码，查看log

#memcached.11211.log
<28 new auto-negotiating client connection
28: Client using the ascii protocol
<28 set key_2 0 0 7
>28 STORED
<28 set key_3 0 0 7
>28 STORED
<28 set key_4 0 0 7
>28 STORED
<28 set key_10 0 0 8
>28 STORED
<28 quit
<28 connection closed.
#memcached.11212.log
<28 new auto-negotiating client connection
28: Client using the ascii protocol
<28 set key_1 0 0 7
>28 STORED
<28 set key_6 0 0 7
>28 STORED
<28 set key_9 0 0 7
>28 STORED
<28 set key_12 0 0 8
>28 STORED
<28 quit
<28 connection closed.
#memcached.11213.log
<28 new auto-negotiating client connection
28: Client using the ascii protocol
<28 set key_7 0 0 7
>28 STORED
<28 set key_8 0 0 7
>28 STORED
<28 quit
<28 connection closed.
#memcached.11214.log
<28 new auto-negotiating client connection
28: Client using the ascii protocol
<28 set key_5 0 0 7
>28 STORED
<28 set key_11 0 0 8
>28 STORED
<28 quit
<28 connection closed.

查看key的散布

正文掉php代码中的11214//$memcached->addServer('192.168.75.132', '11214');
再次执行php代码
查看key的散布

比照两次key的散布：

key_2以及key_10掷中不变化，始终正在11211中，其余10个key由于效劳器的缩小掷中发作变动

3.分歧性hash算法

php代码

<?php
/**
 * Created by PhpStorm.
 * User: jmsite.cn
 * Date: 2019/1/28
 * Time: 11:38
 */
$memcached = new Memcached();
//设置算法为分歧性hash
$memcached->setOptions(
    array(
        Memcached::OPT_DISTRIBUTION         => Memcached::DISTRIBUTION_CONSISTENT,
        Memcached::OPT_LIBKETAMA_COMPATIBLE => true,
        Memcached::OPT_REMOVE_FAILED_SERVERS=> true,
    )
);
//增加效劳器
$memcached->addServer('192.168.75.132', '11211');
$memcached->addServer('192.168.75.132', '11212');
$memcached->addServer('192.168.75.132', '11213');
$memcached->addServer('192.168.75.132', '11214');
//写入12个key
for ($i =1;$i <= 12;$i++){
    $ret = $memcached->set('key_'.$i, 'value_'.$i);
}

执行上述代码，查看log

查看key的散布

正文掉php代码中的11214//$memcached->addServer('192.168.75.132', '11214');
再次执行php代码
查看key的散布

比照两次key的散布：

11211原本的key掷中不发作变动，新增了key_4

11212原本的key掷中不发作变动

11213原本的key掷中不发作变动，新增了key_12

有2个key由于效劳器的缩小掷中发作变动

4.比照

取模hash算法缩小一台效劳器有10个key掷中发作了变动。

分歧性hash算法缩小一台效劳器2个key掷中发作了变动。

这里只测试了12个key，模仿的数据量过小招致key散布没有平均，但效劳器缩小招致key掷中发作变动以及模仿数据量巨细有关，而是以及hash算法无关，这些测试表现了分歧性hash算法的劣势，取模hash由于效劳器的缩小招致年夜量key的取模后果发作变动，掷中的效劳器也发作了变动；而分歧性hash算法key是固定正在一个有2^32-1个节点的hash环上，效劳器缩小key正在hash环上的地位没有会发作变动，仅仅影响缩小的那台效劳器上key的掷中，添加效劳器也仅仅影响hash环上下一个地位效劳器的局部key罢了

以上就是PHP取模hash以及分歧性hash操作Memcached散布式集群的具体内容，更多请存眷资源魔其它相干文章！