Fatal error: Uncaught Error: Call to undefined function mysql_pconnect() in /volume1/web/db.php on line 11

Error: Call to undefined function mysql_pconnect() in /volume1/web/db.php on line 11

Call Stack:
    0.0001     357824   1. {main}() /volume1/web/my_exercise.php:0
    0.0002     358712   2. include('/volume1/web/db.php') /volume1/web/my_exercise.php:4