mysql研究

1. mysql关键日志----慢查询日志

   查看slow log位置

mysql> show variables like '%slow%'
    -> ;
+---------------------+------------------------------------------+
| Variable_name       | Value                                    |
+---------------------+------------------------------------------+
| log_slow_queries    | OFF                                      |
| slow_launch_time    | 2                                        |
| slow_query_log      | OFF                                      |
| slow_query_log_file | /user/database/mysql/PSBJ-0-0-0-slow.log |
+---------------------+------------------------------------------+
4 rows in set (0.00 sec)

   开启慢查询：

mysql> set global  slow_query_log=on;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%slow%';
+---------------------+------------------------------------------+
| Variable_name       | Value                                    |
+---------------------+------------------------------------------+
| log_slow_queries    | ON                                       |
| slow_launch_time    | 2                                        |
| slow_query_log      | ON                                       |
| slow_query_log_file | /user/database/mysql/PSBJ-0-0-0-slow.log |
+---------------------+------------------------------------------+
4 rows in set (0.00 sec)