You have a config file for a running DB with this excerpt:

[mysqld]

tmp_table_size=16M

sort_buffer_size=256k

To address a query performance problem of connecting to the DB from an application on another host, you log in and make these changes to the DB:

mysql> SET GLOBAL tmp_table_size=32000000;

mysql> SET sort_buffer_size=2000000;

This solves the problem with your queries. However, later the DB instance is restarted and the performance problem returns.

Which three best describe this scenario?