php如何实现数据库连接池监控

在PHP中实现数据库连接池监控，可以通过以下几个步骤来完成：

1. 创建一个数据库连接池类（DBPool）：

class DBPool {
    private $connections = [];
    private $maxConnections = 10;
    private $connectionTimeout = 30;
    private $dbHost = 'localhost';
    private $dbName = 'test_db';
    private $dbUser = 'username';
    private $dbPassword = 'password';

    public function getConnection() {
        if (empty($this->connections)) {
            for ($i = 0; $i < $this->maxConnections; $i++) {
                $connection = new mysqli($this->dbHost, $this->dbUser, $this->dbPassword, $this->dbName);
                if ($connection->connect_error) {
                    throw new Exception("Failed to connect to database: " . $connection->connect_error);
                }
                $this->connections[] = $connection;
            }
        }

        $key = array_rand($this->connections);
        return $this->connections[$key];
    }

    public function releaseConnection($connection) {
        if (in_array($connection, $this->connections)) {
            $connection->close();
            unset($this->connections[array_search($connection, $this->connections)]);
        }
    }
}

2. 创建一个监控类（DBPoolMonitor）：

class DBPoolMonitor {
    private $dbPool;

    public function __construct(DBPool $dbPool) {
        $this->dbPool = $dbPool;
    }

    public function getConnectionCount() {
        return count($this->dbPool->getConnections());
    }

    public function getActiveConnections() {
        $connections = [];
        foreach ($this->dbPool->getConnections() as $connection) {
            if ($connection->is_connected()) {
                $connections[] = $connection;
            }
        }
        return count($connections);
    }

    public function getIdleConnections() {
        $connections = [];
        foreach ($this->dbPool->getConnections() as $connection) {
            if (!$connection->is_connected()) {
                $connections[] = $connection;
            }
        }
        return count($connections);
    }
}

3. 使用监控类监控数据库连接池：

$dbPool = new DBPool();
$monitor = new DBPoolMonitor($dbPool);

echo "Total connections: " . $monitor->getConnectionCount() . PHP_EOL;
echo "Active connections: " . $monitor->getActiveConnections() . PHP_EOL;
echo "Idle connections: " . $monitor->getIdleConnections() . PHP_EOL;

这个示例中，我们创建了一个数据库连接池类（DBPool），用于管理数据库连接。同时，我们还创建了一个监控类（DBPoolMonitor），用于监控数据库连接池的状态，如总连接数、活动连接数和空闲连接数。最后，我们使用这两个类来监控数据库连接池。