由於CPanel即將全面升級到PHP8以上的版本，並不再支援以下的版本
所以目前再對網站進行升級準備

網站利用 session_set_save_handler 將 session 儲存在 mysql 中
升級後出現以下錯誤訊息
PHP Warning: session_start(): Failed to read session data: user (path: {主機端路徑}) in {引用檔案路徑} on line 4
原始碼如下：

<?php
	require_once dirname(__FILE__)."/define.php";  //將資料庫參數設定為靜態值的檔案

	function getConnection(){
		$conn = new PDO(DB_TYPE.':host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASSWD, array(PDO::MYSQL_ATTR_INIT_COMMAND=>"SET NAMES'utf8';"));
		$conn->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
		$conn->setAttribute(PDO::ATTR_EMULATE_PREPARES,false);
		$conn->query('SET NAMES UTF8');
		return $conn;
	}

	function sess_open($save_path, $session_name){
		$dbh = getConnection();

		try{
			$dbh->query("SELECT 1");
		}catch(PDOException $e){
			die("MySQL Error:".$e->getMessage());
		}
		return true;
	}

	function sess_close(){
		return true;
	}

	function sess_read($key){
		$dbh = getConnection();
		$sql = "SELECT `value` FROM `db_session` WHERE `sesskey`=:sesskey AND `expiry`>UNIX_TIMESTAMP()";
		$sth = $dbh->prepare($sql);
		$sth->bindParam(":sesskey", $key, PDO::PARAM_STR, 32);
		$sth->execute();
		$data = $sth->fetchAll();
		if(count($data) > 0) return $data[0]["value"];
		return false;
	}

	function sess_write($key, $val){
		$dbh = getConnection();
		$expiry = time() + SESS_LIFE;
		$sql = "INSERT INTO `db_session` (`sesskey`, `expiry`, `value`) VALUES (:sesskey, :expiry1, :value1) ON DUPLICATE KEY UPDATE `expiry`=:expiry2,`value`=:value2";
		$sth = $dbh->prepare($sql);
		$sth->bindParam(":sesskey", $key, PDO::PARAM_STR, 32);
		$sth->bindParam(":expiry1", $expiry, PDO::PARAM_INT);
		$sth->bindParam(":value1", $val, PDO::PARAM_STR);
		$sth->bindParam(":expiry2", $expiry, PDO::PARAM_INT);
		$sth->bindParam(":value2", $val, PDO::PARAM_STR);
		$sth->execute();
		return ($sth->errorCode() == "00000")?true:false;
	}

	function sess_destroy($key){
		$dbh = getConnection();
		$sql = "DELETE FROM `db_session` WHERE `sesskey`=:sesskey";
		$sth = $dbh->prepare($sql);
		$sth->bindParam(":sesskey", $key, PDO::PARAM_STR, 32);
		$sth->execute();
		return ($sth->errorCode() == "00000")?true:false;
	}

	function sess_gc($maxlifetime){
		$dbh = getConnection();
		$sql = "DELETE FROM `db_session` WHERE `expiry`<UNIX_TIMESTAMP()";
		$sth = $dbh->prepare($sql);
		$sth->execute();
		return ($sth->errorCode() == "00000")?true:false;
	}

	ini_set('session.gc_maxlifetime', SESS_LIFE);
	ini_set('session.gc_probability', '1');
	ini_set('session.gc_divisor', '1');

	session_set_save_handler("sess_open", "sess_close", "sess_read", "sess_write", "sess_destroy", "sess_gc");
?>

查了一下，PHP目前傾向 session_set_save_handler 不支援兩個以上的參數
有修改成下面的進行測試，依然不行

<?php
	require_once dirname(__FILE__)."/define.php";  //將資料庫參數設定為靜態值的檔案

	class SysSession implements SessionHandlerInterface
	{
		private $dbh;
		function __construct()
		{
			$conn = new PDO(DB_TYPE.':host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASSWD, array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES'utf8';"));
			$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
			$conn->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
			$conn->query('SET NAMES UTF8');
			$this->dbh = $conn;
		}
		public function open($savePath, $sessionName): bool
		{
			try {
				$this->dbh->query("SELECT 1");
			} catch (PDOException $e) {
				//die("MySQL Error:".$e->getMessage());
				return false;
			}
			return true;
		}
		public function close(): bool
		{
			$this->dbh = null;
			return true;
		}
		public function read($key): string | false
		{
			$sql = "SELECT `value` FROM `db_session` WHERE `sesskey`=:sesskey AND `expiry`>UNIX_TIMESTAMP()";
			$sth = $this->dbh->prepare($sql);
			$sth->bindParam(":sesskey", $key, PDO::PARAM_STR, 32);
			$sth->execute();
			$data = $sth->fetchAll();
			return count($data) ? $data[0]["value"] : false;
		}
		public function write($key, $val): bool
		{
			$expiry = time() + SESS_LIFE;
			$sql = "REPLACE INTO `db_session` (`sesskey`, `expiry`, `value`) VALUES (:sesskey, :expiry, :value)";
			$sth = $this->dbh->prepare($sql);
			$sth->bindParam(":sesskey", $key, PDO::PARAM_STR, 32);
			$sth->bindParam(":expiry", $expiry, PDO::PARAM_INT);
			$sth->bindParam(":value", $val, PDO::PARAM_STR);
			$sth->execute();
			return ($sth->errorCode() == "00000") ? true : false;
		}
		public function destroy($key): bool
		{
			$sql = "DELETE FROM `db_session` WHERE `sesskey`=:sesskey";
			$sth = $this->dbh->prepare($sql);
			$sth->bindParam(":sesskey", $key, PDO::PARAM_STR, 32);
			$sth->execute();
			return ($sth->errorCode() == "00000") ? true : false;
		}
		public function gc($maxlifetime): int | false
		{
			$sql = "DELETE FROM `db_session` WHERE `expiry`<UNIX_TIMESTAMP()";
			$sth = $this->dbh->prepare($sql);
			$sth->execute();
			return ($sth->errorCode() == "00000") ? true : false;
		}
	}

	ini_set('session.gc_maxlifetime', SESS_LIFE);
	ini_set('session.gc_probability', '1');
	ini_set('session.gc_divisor', '1');

	$handler = new SysSession();
	session_set_save_handler($handler, true);
?>

這邊是引用的測試檔

<?php
	require_once dirname(__FILE__)."/include/session_mysql.php";

	session_start();  //報錯的地方
	$a = isset($_SESSION["a"])?(int)$_SESSION["a"]:1;
	$_SESSION["a"] = $a + 1;
	echo $a;
?>

請問我是哪邊寫錯了嗎?