CI Framework Connection database resource cannot be freed

Query data using the classes provided by the CI framework:

$this->load->database ();
$query = $this->db->query ($sql);

After the program runs for a period of time, error, inform the database too many connections

It is obvious that the MySQL database connection resource exceeds the Max_connections setting. Immediately after each query, add the resource release script:

$this->db->close ();

Still unable to release resources, how to do? After viewing the manual, you know, just set the Pconnect to False, the settings are as follows:

$db [' Default '] [' pconnect '] = FALSE;

After setting, no call $this->db->close (); To automatically close the connection.

CI Framework Connection database resource cannot be freed