详解基于swoole的mysql连接池实现

swoole框架栏目介绍swoole实现mysql连接池的方法

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前言

传统的nginx+FPM模式的PHP程序而言，每次请求FPM的worker都会连接一次mysql，然后请求结束便会断开连接。对于并发小的应用来说这不会有什么问题，但是对于高并发的应用来说，频繁建立连接Connect和销毁连接Close，数据库便会成为瓶颈，相信不少人也遇到过to many connection的mysql报错吧。

连接池的优势

连接池采用的是长连接模式，会一直保持与MySQL的连接，用完后会重新放回连接池，从而节省了建立连接和断开连接的消耗，大大降低了系统IO的消耗，一定程度上提高了程序的并发性能。如果连接池空闲，就从连接池分配一个连接，否则，请求将被加入到等待队列中。

实现

我们采用swoole实现mysql连接池

连接池类

<?php  require_once "MysqlDB.php";class MysqlPool{     private static $instance;     private $pool;     private $config;     private $pool_get_timeout;      /**      * 获取mysql进程池单例      * @param null $config      * @return MysqlPool      */     public static function getInstance($config = null)     {         if (empty(self::$instance)) {             if (empty($config)) {                 throw new RuntimeException("mysql config is empty");             }             self::$instance = new static($config);         }         return self::$instance;     }      public function __construct($config)     {         if (empty($this->pool)) {             $this->config = $config;             $this->pool = new SwooleCoroutineChannel($config['pool_size']);             for ($i = 0; $i < $config['pool_size']; $i++) {                 go(function() use ($config) {                     $mysql = new MysqlDB();                     $res = $mysql->connect($config['mysql']);                     if ($res === false) {                         throw new RuntimeException("Failed to connect mysql server");                     } else {                         $this->pool->push($mysql);                     }                 });             }         }     }      public function get()     {         if ($this->pool->length() > 0) {             $mysql = $this->pool->pop($this->config['pool_get_timeout']);             if (false === $mysql) {                 throw new RuntimeException("Pop mysql timeout");             }             return $mysql;         } else {             throw new RuntimeException("Pool length <= 0");         }     }      public function recycle(MysqlDB $mysql){         $this->pool->push($mysql);     }      /**      * 获取连接池长度      * @return mixed      */     public function getPoolSize(){         return $this->pool->length();     }}

数据库DB类

<?phpclass MysqlDB{     private $connection;      public function connect($config)     {         $connection = new SwooleCoroutineMySQL();         $res = $connection->connect($config);         if ($res === false) {             throw new RuntimeException($connection->connect_error, $connection->errno);         } else {             $this->connection = $connection;         }         return $res;     }       public function query($sql){         $result = $this->connection->query($sql);         return $result;     }}

在HTTP协程服务器中创建连接池

<?php require_once "MysqlPool.php";Corun(function () {     $server = new CoHttpServer("0.0.0.0", 9501, false);     $pool = MysqlPool::getInstance([         'pool_size'=>5,         'pool_get_timeout'=>1,         'timeout'=>1,         'charset'=>'utf8',         'strict_type'=>false,         'fetch_mode'=>true,         'mysql'=>[             'host'=>'127.0.0.1',             'port'=>'3306',             'user'=>'homestead',             'password'=>'secret',             'database'=>'blog',         ]     ]);     $server->handle('/', function ($request, $response) use ($pool){         $mysql = $pool->get();         $res = $mysql->query("select id,phone,username from user limit 1");         var_dump($res);         $pool->recycle($mysql);         $response->end("<h1>Test</h1>");     });     $server->handle('/test', function ($request, $response) {         $response->end("<h1>Test</h1>");     });     $server->handle('/stop', function ($request, $response) use ($server) {         $response->end("<h1>Stop</h1>");         $server->shutdown();     });     $server->start();});

源码地址 swoole-mysql-pool

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