# free -m

# ps aux | egrep 'mysqld|VSZ'

# vmstat 1

# iostat -xk 1

# mpstat -P ALL 1

mysql> SHOW GLOBAL STATUS LIKE 'Open%tables';
mysql> SHOW GLOBAL VARIABLES WHERE variable_name = 'max_connections' OR variable_name = 'table_open_cache';

mysql> SELECT COUNT(*) FROM information_schema.tables;

mysql> SELECT * FROM employee WHERE last = 'Mueller';

mysql> EXPLAIN SELECT * FROM employee WHERE last = 'Mueller';
mysql> ALTER TABLE employee ADD INDEX (last);
mysql> EXPLAIN SELECT * FROM employee WHERE last = 'Mueller';

mysql> SET GLOBAL slow_query_log = 1;
mysql> SET GLOBAL long_query_time = 0.200;

mysql> SHOW GLOBAL VARIABLES   LIKE 'slow%file';