ubuntu系统安装多mysql服务器怎么安装。。。

php重复连接mysql会有问题吗？有什么不好的吗？如下：
<?php
$connect=new mysqli("localhost","root","123456","book_comment");
$connect1=new mysqli("localhost","root","123456","book_comment");
$connect2=new mysqli("localhost","root","123456","book_comment");
$connect3=new mysqli("localhost","root","123456","book_comment");
$connect4=new mysqli("localhost","root","123456","book_comment");
$connect5=new mysqli("localhost","root","123456","book_comment");
?>