Using Persistent Connections
The MySQL database extensions do not support persistent connections when used with the MySQL Client Library. However, they do when using MySQL Native Driver. When creating a connection the hostname is prepended with "p:". This is demonstrated by the following code snippet, which creates a new connection using mysqli:
$host="p:localhost";
$port=3306;
$socket="/tmp/mysql.sock";
$user="root";
$password="password";
$dbname="test";
$conn = new mysqli($host, $user, $password, $dbname, $port, $socket)
or die ('Could not connect to the database server' . mysqli_connect_error());