PHP+MYSQL 讀寫分離簡單實戰

一、Introduction

以前寫過2篇文章，分別是：

Mysql主從同步的原理
Myql主從同步實戰

基於此，咱們再實現簡單的PHP+Mysql讀寫分離，從而提升數據庫的負載能力。

二、代碼實戰

<?php
class Db
{
    private $res;
    function __construct($sql)
    {
        $querystr = strtolower(trim(substr($sql,0,6)));
        //若是是select，就鏈接slave服務器
        if($querystr == 'select')
        {
            $res=$this->slave_select($sql);
            $this->res=$res;
        }
        //若是不是select，就鏈接master服務器
        else
        {
            $res=$this->master_change($sql);
            $this->res=$res;
        }
    }

    /**
     * slave從庫返回sql查詢結果
     * @param $sql
     * @return array
     */
    private function slave_select($sql){
        //該處只是隨機獲取slave節點的ip，固然，還能夠採用其餘算法獲取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主庫返回sql執行結果
     * @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);
    }

    /**
     * 隨機獲取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];
    }

    /**
     * 獲取結果
     * @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());

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