MySQL 使用 profiling

在工作中，经常会遇到要优化语句的场景，MySQL的Query Profiler就是一个很好的工具，使用方法也很简单，介绍如下：

mysql> set profiling=1;                                /*开启profiling*/
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%profiling%';
+------------------------+-------+
| Variable_name          | Value |
+------------------------+-------+
| have_profiling         | YES   |
| profiling              | ON    |
| profiling_history_size | 15    |
+------------------------+-------+
3 rows in set (0.01 sec)

mysql> select * from user;
mysql> show profiles;
+----------+------------+--------------------+
| Query_ID | Duration   | Query              |
+----------+------------+--------------------+
|        1 | 0.00834675 | select * from user |
+----------+------------+--------------------+
1 row in set (0.00 sec)

mysql> set profiling=0;                      /*关闭profiling*/
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%profiling%';
+------------------------+-------+
| Variable_name          | Value |
+------------------------+-------+
| have_profiling         | YES   |
| profiling              | OFF   |
| profiling_history_size | 15    |
+------------------------+-------+
3 rows in set (0.00 sec)

这就是MySQL profiling的一个简单的使用方法。