What are the differences between using relative and absolute path references in PHP when handling file uploads, and which is recommended for better performance?

When handling file uploads in PHP, using relative path references can be more flexible but may cause performance issues due to the need to resolve the path. On the other hand, using absolute path references can provide better performance as they directly point to the file location on the server. It is recommended to use absolute path references for better performance when handling file uploads in PHP.

// Using absolute path reference for file upload
$uploadDir = '/var/www/html/uploads/';
$uploadFile = $uploadDir . basename($_FILES['file']['name']);

if (move_uploaded_file($_FILES['file']['tmp_name'], $uploadFile)) {
    echo "File is valid, and was successfully uploaded.";
} else {
    echo "Possible file upload attack!";
}