为什么不记录慢查询？

㈠ 背景介绍： ㈡ 定位原因： INSERT INTO t (col1, col2, col3, col4, col5, col6, col7) VALUES (3532082239485507011_130_99, 130_99, 130, 99, 3532082239485507011, 2172353000317425008, 29078) ㈢ 处理思路： select trx_id,trx_state,trx_started,tr

INSERT INTO t (col1, col2, col3, col4, col5, col6, col7) VALUES ('3532082239485507011_130_99', '130_99', 130, 99, 3532082239485507011, 2172353000317425008, 29078) 

select trx_id,trx_state,trx_started,trx_requested_lock_id,trx_weight,trx_mysql_thread_id from information_schema.innodb_trx where trx_state='RUNNING';

㈣ 我的疑问：
㈤ 原来如此：
㈥ 模拟场景：

Session_A：

mysql> begin;
Query OK, 0 rows affected (0.00 sec)

mysql> select emp_no,hire_date from employees where emp_no=10170 for update;
+--------+------------+
| emp_no | hire_date  |
+--------+------------+
|  10170 | 1986-01-02 |
+--------+------------+
1 row in set (0.00 sec)

Session_B:

mysql> select emp_no,hire_date,sleep(3) from employees where emp_no=10170 for update;

过段时间在A做commit，B会执行、并被记录到slow log中：

# Time: 140818 22:37:31
# User@Host: root[root] @ localhost []  Id:     1
# Query_time: 3.049016  Lock_time: 0.018891 Rows_sent: 1  Rows_examined: 1
use employees;
SET timestamp=1408372651;
select emp_no,hire_date,sleep(3) from employees where emp_no=10170 for update;

Session_A：

mysql> begin;
Query OK, 0 rows affected (0.00 sec)

mysql> select emp_no,hire_date from employees where emp_no=10170 for update;
+--------+------------+
| emp_no | hire_date  |
+--------+------------+
|  10170 | 1986-01-02 |
+--------+------------+
1 row in set (0.00 sec)

Session_B:

mysql> select emp_no,hire_date from employees where emp_no=10170 for update;

㈦ 我的收获：

我们日常做性能剖析实际上应该包括2个方面：

1）基于执行时间的分析

2）基于等待时间的分析

By water

Good Luck！