参考文章

在分析innodb中锁阻塞时，几种方法的对比情况：
（1）使用show processlist查看不靠谱；
（2）直接使用show engine innodb status查看，无法判断到问题的根因；
（3）使用mysqladmin debug查看，能看到所有产生锁的线程，但无法判断哪个才是根因；
（4）开启innodb_lock_monitor后，再使用show engine innodb status查看，能够找到锁阻塞的根因。

查询进程

  1. show processlist;

查询到相对应的进程，然后 kill id

kill 2323

查询是否锁表

show OPEN TABLES where In_use > 0;

查看正在锁的事务

SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCKS;

查看等待锁的事务

SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCK_WAITS;

查看锁阻塞线程信息

show engine innodb status

使用innodb_lock_monitor来获取阻塞锁线程

MySQL [test]> CREATE TABLE innodb_lock_monitor (a INT) ENGINE=INNODB;  ## 随便在一个数据库中创建这个表，就会打开lock monitor  
Query OK, 0 rows affected, 1 warning (0.07 sec)  

MySQL [test]> show warnings\G  
*************************** 1. row ***************************  
  Level: Warning  
   Code: 131  
Message: Using the table name innodb_lock_monitor to enable diagnostic output is deprecated and may be removed in future releases. Use INFORMATION_SCHEMA or PERFORMANCE_SCHEMA tables or SET GLOBAL innodb_status_output=ON.  
1 row in set (0.00 sec)

查看表锁的情况

mysql> show status like 'table%';
+----------------------------+---------+
| Variable_name | Value |
+----------------------------+---------+
| Table_locks_immediate | 100 |
| Table_locks_waited | 11 |
+----------------------------+---------+

查看InnoDB_row_lock状态变量来分析系统上的行锁的争夺情况

mysql> show status like 'InnoDB_row_lock%';
+-------------------------------+--------+
| Variable_name                 | Value  |
+-------------------------------+--------+
| Innodb_row_lock_current_waits | 0      |
| Innodb_row_lock_time          | 159372 |
| Innodb_row_lock_time_avg      | 39843  |
| Innodb_row_lock_time_max      | 51154  |
| Innodb_row_lock_waits         | 4      |
+-------------------------------+--------+
5 rows in set (0.01 sec)