php - How to use mysqli persistent connection across different pages

Question

I have a web app that uses different PHP pages to process code.

At the top of each page, I open a mysqli connection to the same database (with the same user/password):

$link = mysqli_connect("$mysql_server", "$mysql_user", "$mysql_pw", "$mysql_db");
if (!$link) {
    die('Could not connect: ' . mysql_error());
}

I understand it's better to use a single persistent connection. How can I enable this across all pages?

Is it has easy as just using $link = mysqli_connect("p:" . $mysql_server, "$mysql_user", "$mysql_pw", "$mysql_db"); for the first connection?

Under what circumstances would this connection close?

Answer 1

$db = mysqli_connect("p:notlocalhost","notroot","","catalog") or die("Error " . mysqli_error($link));

It is "p:" - when prepended before hostname, creates persistent connection. That is later reused on different pages. You still call same constructor on every page.