PHP+MYSQL 读写分离简单实战

1、Introduction

之前写过2篇文章，分别是：

Mysql主从同步的原理

Myql主从同步实战

基于此，我们再实现简单的php+Mysql读写分离，从而提高数据库的负载能力。

2、代码实战

<?php  class Db  {  private $res;  function __construct($sql)  {  $querystr = strtolower(trim(substr($sql,0,6)));  //如果是select，就连接slave服务器  if($querystr == 'select')  {  $res=$this->slave_select($sql);  $this->res=$res;  }  //如果不是select，就连接master服务器  else  {  $res=$this->master_change($sql);  $this->res=$res;  }  }  /**  * slave从库返回sql查询结果  * @param $sql  * @return array  */  private function slave_select($sql){  //该处只是随机获取slave节点的ip，当然，还可以采用其他算法获取slave_ip  $slave_server=$this->get_slave_ip();  $dsn="mysql:host=$slave_server;dbname=test";  $user='root';  $pass='123456';  $dbh=new PDO($dsn, $user, $pass);  return $dbh->query($sql)->fetchAll(PDO::FETCH_ASSOC);  }  /**master主库返回sql执行结果  * @param $sql  * @return int  */  private function master_change($sql){  $master_server='192.168.33.22';  $dsn="mysql:host=$master_server;dbname=test";  $user='root';  $pass='123456';  $dbh=new PDO($dsn, $user, $pass);  return $dbh->exec($sql);  }  /**  * 随机获取slave-ip  * @return mixed  */  private function get_slave_ip(){  $slave_ips=['192.168.33.33','192.168.33.44'];  $count=count($slave_ips)-1;  $random_key=mt_rand(0,$count);  return $slave_ips[$random_key];  }  /**  * 获取结果  * @return int  */  public function get_res(){  return $this->res;  }  }  $sql1 = "select * from t1";  $sql2 = "insert into t1 (name) values ('haha')";  $sql3 = "delete from t1 where id=1";  $sql4 = "update t1 set name='Jerry' where id=2";  $db = new Db($sql1);  //$db = new Db($sql2);  //$db = new Db($sql3);  //$db = new Db($sql4);  var_dump($db->get_res());

原文链接：https://segmentfault.com/a/1190000008664288