SET GLOBAL mroonga_log_file = "new-mroonga.log";
SHOW GLOBAL VARIABLES LIKE 'mroonga_log_file';
Variable_name	Value
mroonga_log_file	new-mroonga.log
SET GLOBAL mroonga_log_file = "nonexistent/mroonga.log";
SHOW GLOBAL VARIABLES LIKE 'mroonga_log_file';
Variable_name	Value
mroonga_log_file	new-mroonga.log
