How can persistent connections in PHP (mysql_pconnect) impact the efficiency of connecting to a SQL server?

Persistent connections in PHP (mysql_pconnect) can impact the efficiency of connecting to a SQL server by potentially causing resource exhaustion on the server due to a large number of persistent connections being kept open. This can lead to decreased performance and potential server crashes. To solve this issue, it is recommended to use regular connections (mysql_connect) instead of persistent connections to ensure that connections are properly closed after each use.

// Establish a regular connection to the MySQL server
$connection = mysql_connect("localhost", "username", "password");

// Check if the connection was successful
if (!$connection) {
    die("Connection failed: " . mysql_error());
}

// Select the database
mysql_select_db("database_name", $connection);