Connection pooling vs persist connection mysqli

Hi, I am php developer please answer my silly question. I've read that mysqli introduced connection pooling that was not available in mysql.http://php.net/manual/en/mysqli.quickstart.connections.php I've read this question that explains the difference between connection pooling and persist connections.In the mysqli documentation for Persistent connection they have written that:If a unused persistent connection for a given combination of host, username, password, socket, port and default database can not be found in the connection pool, then mysqli opens a new connection. So, does mysqli use connection pooling for persistent connections?If yes, then what is difference between connection pooling and persistent connections in mysqli?If no, then how does mysqli perform a lookup for a connection object for a persistent connection? http://stackoverflow.com/questions/24902615/connection-pooling-vs-persist-connection-mysqli