config root man

Bug#25650399: DOWNGRADE FROM MYSQL 8.0 WITH WL#10128 TO 5.7
WILL CRASH SERVER

ALTER TABLE mysql.server_cost
ADD COLUMN default_value FLOAT GENERATED ALWAYS AS (cost_name) VIRTUAL;
ALTER TABLE mysql.engine_cost
ADD COLUMN default_value FLOAT GENERATED ALWAYS AS (cost_name) VIRTUAL;
FLUSH OPTIMIZER_COSTS;
mysql.columns_priv                                 OK
mysql.db                                           OK
mysql.engine_cost                                  OK
mysql.event                                        OK
mysql.func                                         OK
mysql.general_log                                  OK
mysql.gtid_executed                                OK
mysql.help_category                                OK
mysql.help_keyword                                 OK
mysql.help_relation                                OK
mysql.help_topic                                   OK
mysql.innodb_index_stats                           OK
mysql.innodb_table_stats                           OK
mysql.ndb_binlog_index                             OK
mysql.plugin                                       OK
mysql.proc                                         OK
mysql.procs_priv                                   OK
mysql.proxies_priv                                 OK
mysql.server_cost                                  OK
mysql.servers                                      OK
mysql.slave_master_info                            OK
mysql.slave_relay_log_info                         OK
mysql.slave_worker_info                            OK
mysql.slow_log                                     OK
mysql.tables_priv                                  OK
mysql.time_zone                                    OK
mysql.time_zone_leap_second                        OK
mysql.time_zone_name                               OK
mysql.time_zone_transition                         OK
mysql.time_zone_transition_type                    OK
mysql.user                                         OK
mtr.global_suppressions                            OK
mtr.test_suppressions                              OK
sys.sys_config                                     OK
SELECT * FROM mysql.server_cost;
cost_name	cost_value	last_update	comment
disk_temptable_create_cost	NULL	#	NULL
disk_temptable_row_cost	NULL	#	NULL
key_compare_cost	NULL	#	NULL
memory_temptable_create_cost	NULL	#	NULL
memory_temptable_row_cost	NULL	#	NULL
row_evaluate_cost	NULL	#	NULL
SELECT * FROM mysql.engine_cost;
engine_name	device_type	cost_name	cost_value	last_update	comment
default	0	io_block_read_cost	NULL	#	NULL
default	0	memory_block_read_cost	NULL	#	NULL