Question

Something I have always wondered, it seems that virtually no PHP applications ever explicitly close MySQL connections mysqli_close().

How does this work? Does PHP automagically close MySQL connections when scripts stop executing?

Answer 1

Yes, the connection will be closed unless it is a persistent connection (opened with a p: before the host). Non-persistent resources are freed automatically at the end of the script, because there are no more references to them.

From the PHP manual:

Thanks to the reference-counting system introduced with PHP 4’s Zend Engine, a resource with no more references to it is detected automatically, and it is freed by the garbage collector. For this reason, it is rarely necessary to free the memory manually.