Execute stored procedure

[eluser]HugoA[/eluser]
Hi!
I'm executing a store procedure like this

Code:

$query = $this->db->query('CALL getPersona()');

but it just work one time (the first one), then, I have to restart the apache server because if I don't do it I get this error

A Database Error Occurred

Unable to select the specified database: todo

If I query mi database like this

Code:

$this->db->where('idpersona','1');
$query = $this->db->get('persona');

There's no problem at all...

What I'm doing wrong when I execute the stored procedure?

Thanks!