PHP の高同時処理におけるリソース管理手法の探求

class DbConnectionPool {
   private static $instance;
   private $connections;
  
   private function __construct() {
      $this->connections = new SplQueue();
   }
  
   public static function getInstance() {
      if (!isset(self::$instance)) {
         self::$instance = new DbConnectionPool();
      }
      return self::$instance;
   }
  
   public function getConnection() {
      if (!$this->connections->isEmpty()) {
         return $this->connections->dequeue();
      } else {
         return $this->createConnection();
      }
   }
  
   public function releaseConnection($connection) {
      $this->connections->enqueue($connection);
   }
  
   private function createConnection() {
      // 创建数据库连接的代码
   }
}

// 获取数据库连接
$dbConnection = DbConnectionPool::getInstance()->getConnection();

// 执行数据库操作
// ...

// 释放数据库连接
DbConnectionPool::getInstance()->releaseConnection($dbConnection);

class Cache {
   private static $redis;
  
   public static function init() {
      self::$redis = new Redis();
      self::$redis->connect('127.0.0.1', 6379);
   }
  
   public static function set($key, $value, $ttl = 0) {
      self::$redis->set($key, $value);
      if ($ttl > 0) {
         self::$redis->expire($key, $ttl);
      }
   }
  
   public static function get($key) {
      return self::$redis->get($key);
   }
  
   public static function delete($key) {
      self::$redis->delete($key);
   }
  
   public static function flush() {
      self::$redis->flushAll();
   }
}

// 初始化缓存
Cache::init();

// 查询缓存
$data = Cache::get('key');
if (!$data) {
   // 从数据库查询数据
   $data = $db->query('SELECT * FROM table')->fetchAll();
   // 将查询结果存入缓存
   Cache::set('key', $data, 60); // 设置缓存生存时间为60秒
}

// 使用数据
foreach ($data as $item) {
   // ...
}

// 开始事务
$db->beginTransaction();

// 加锁
$db->query('SELECT * FROM table WHERE id = 1 FOR UPDATE');

// 读取数据并做修改
$data = $db->query('SELECT * FROM table WHERE id = 1')->fetch();
$data['field'] += 1;

// 更新数据
$db->exec('UPDATE table SET field = ' . $data['field'] . ' WHERE id = 1');

// 提交事务
$db->commit();