~~~ mysql> show variables like "%long%"; //查看一下默認為慢查詢的時間10秒 +--------------------------------------------------------+----------+ | Variable_name | Value | +--------------------------------------------------------+----------+ | long_query_time | 1.000000 | | performance_schema_events_stages_history_long_size | 1000 | | performance_schema_events_statements_history_long_size | 1000 | | performance_schema_events_waits_history_long_size | 1000 | +--------------------------------------------------------+----------+ 4 rows in set (0.00 sec) ~~~ ~~~ mysql> set global long_query_time=2; //設置成2秒，加上global,下次進mysql已然生效 Query OK, 0 rows affected (0.00 sec) ~~~ ~~~ mysql> show variables like "%slow%"; //查看一下慢查詢是不是已經開啟 +---------------------------+-----------------------------------+ | Variable_name | Value | +---------------------------+-----------------------------------+ | log_slow_admin_statements | OFF | | log_slow_slave_statements | OFF | | slow_launch_time | 2 | | slow_query_log | OFF | | slow_query_log_file | /var/lib/mysql/localhost-slow.log | +---------------------------+-----------------------------------+ 5 rows in set (0.00 sec) ~~~ ~~~ mysql> set slow_query_log='ON'; //加上global，不然會報錯的。 ERROR 1229 (HY000): Variable 'slow_query_log' is a GLOBAL variable and should be set with SET GLOBAL mysql> set global slow_query_log='ON'; //啟用慢查詢 Query OK, 0 rows affected (0.28 sec) ~~~ ~~~ mysql> show variables like "%slow%"; //查看是否已經開啟 +---------------------------+-----------------------------------+ | Variable_name | Value | +---------------------------+-----------------------------------+ | log_slow_admin_statements | OFF | | log_slow_slave_statements | OFF | | slow_launch_time | 2 | | slow_query_log | ON | | slow_query_log_file | /var/lib/mysql/localhost-slow.log | +---------------------------+-----------------------------------+ 5 rows in set (0.00 sec) ~~~ ~~~ set global general_log='ON'; //開啟執行sql日志 show variables like "%log%"; //查看日志是否開啟 ~~~