implies more memory copy. The old method is still available and can be used.
It stays as default. Choosing the method is through a flag to mysqli_query()/mysqli_real_query()
New mode can be forced with an INI setting, for all extensions that support this mode
(ext/mysql and mysqli, because PDO due to it's architecture can't support it)
The setting is mysqlnd.fetch_data_copy=[0|1]
one and just one for libmysql. mysqlnd can return generate more than one error
during its work and with mysqli_error() only the last error is being reported.
In the array returned by mysqli_error_list() / $mysqli->error_list, all errors will be found.
The list is reset when the next command is executed