What is the function mysql_pconnect() useful for?

The mysql_pconnect() function is used to establish a persistent connection to a MySQL database in PHP. A persistent connection allows the PHP script to reuse an existing database connection across multiple requests. This can help improve performance by avoiding the overhead of establishing a new connection for each request. However, it's important to note that the mysql_pconnect() function is part of the deprecated MySQL extension in PHP, and it is not recommended to use this function. Instead, you should use the MySQLi or PDO extensions to establish database connections in PHP, as they provide better security and functionality.