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mysql 查看死锁和去除死锁_empty set, 1 warning (0.00 sec)

作者：cp456 | 2024-01-30 21:00:14

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empty set, 1 warning (0.00 sec)

1、查询进程

show processlist

2、查询到相对应的进程，然后 kill id

验证（kill后再看是否还有锁）

2、查询是否锁表

show OPEN TABLES where In_use > 0;

示例：

新建一个会话执行如下的显示锁示例


LOCK TABLES account_data.account READ;
SELECT SLEEP(160);
UNLOCK TABLES account_data.account;

另开启一个会话检查锁表情况：


mysql> show OPEN TABLES where In_use > 0;
+--------------+---------+--------+-------------+
| Database     | Table   | In_use | Name_locked |
+--------------+---------+--------+-------------+
| account_data | account |      1 |           0 |
+--------------+---------+--------+-------------+
1 row in set (0.00 sec)
mysql> select * from  information_schema.innodb_locks\G;
Empty set, 1 warning (0.00 sec)
ERROR:
No query specified
mysql> show processlist\G;
 1. row 
Id: 5
User: root
Host: 192.168.0.206:64294
db: NULL
Command: Sleep
Time: 4051
State:
Info: NULL
 2. row 
Id: 8
User: root
Host: 192.168.0.206:64297
db: NULL
Command: Sleep
Time: 4042
State:
Info: NULL
 3. row 
Id: 10
User: root
Host: localhost
db: NULL
Command: Query
Time: 0
State: starting
Info: show processlist
 4. row 
Id: 19
User: root
Host: 192.168.0.206:54603
db: account_data
Command: Sleep
Time: 245
State:
Info: NULL
 5. row 
Id: 20
User: root
Host: 192.168.0.206:54604
db: information_schema
Command: Query
Time: 20
State: User sleep
Info: select sleep(160)
5 rows in set (0.00 sec)
ERROR:
No query specified
mysql>

3、在5.5中，information_schema 库中增加了三个关于锁的表（innoDB引擎）：

innodb_trx ## 当前运行的所有事务
innodb_locks ## 当前出现的锁
innodb_lock_waits ## 锁等待的对应关系
先来看一下这三张表结构：


root@127.0.0.1 : information_schema 13:28:38> desc innodb_locks;
+————-+———————+——+—–+———+——-+
| Field       | Type                | Null | Key | Default | Extra |
+————-+———————+——+—–+———+——-+
| lock_id     | varchar(81)         | NO   |     |         |       |#锁ID
| lock_trx_id | varchar(18)         | NO   |     |         |       |#拥有锁的事务ID
| lock_mode   | varchar(32)         | NO   |     |         |       |#锁模式
| lock_type   | varchar(32)         | NO   |     |         |       |#锁类型
| lock_table  | varchar(1024)       | NO   |     |         |       |#被锁的表
| lock_index  | varchar(1024)       | YES  |     | NULL    |       |#被锁的索引
| lock_space  | bigint(21) unsigned | YES  |     | NULL    |       |#被锁的表空间号
| lock_page   | bigint(21) unsigned | YES  |     | NULL    |       |#被锁的页号
| lock_rec    | bigint(21) unsigned | YES  |     | NULL    |       |#被锁的记录号
| lock_data   | varchar(8192)       | YES  |     | NULL    |       |#被锁的数据
+————-+———————+——+—–+———+——-+
10 rows in set (0.00 sec)
root@127.0.0.1 : information_schema 13:28:56> desc innodb_lock_waits;
+——————-+————-+——+—–+———+——-+
| Field             | Type        | Null | Key | Default | Extra |
+——————-+————-+——+—–+———+——-+
| requesting_trx_id | varchar(18) | NO   |     |         |       |#请求锁的事务ID
| requested_lock_id | varchar(81) | NO   |     |         |       |#请求锁的锁ID
| blocking_trx_id   | varchar(18) | NO   |     |         |       |#当前拥有锁的事务ID
| blocking_lock_id  | varchar(81) | NO   |     |         |       |#当前拥有锁的锁ID
+——————-+————-+——+—–+———+——-+
4 rows in set (0.00 sec)
root@127.0.0.1 : information_schema 13:29:05> desc innodb_trx ;
+—————————-+———————+——+—–+———————+——-+
| Field                      | Type                | Null | Key | Default             | Extra |
+—————————-+———————+——+—–+———————+——-+
| trx_id                     | varchar(18)         | NO   |     |                     |       |#事务ID
| trx_state                  | varchar(13)         | NO   |     |                     |       |#事务状态：
| trx_started                | datetime            | NO   |     | 0000-00-00 00:00:00 |       |#事务开始时间；
| trx_requested_lock_id      | varchar(81)         | YES  |     | NULL                |       |#innodb_locks.lock_id
| trx_wait_started           | datetime            | YES  |     | NULL                |       |#事务开始等待的时间
| trx_weight                 | bigint(21) unsigned | NO   |     | 0                   |       |#
| trx_mysql_thread_id        | bigint(21) unsigned | NO   |     | 0                   |       |#事务线程ID
| trx_query                  | varchar(1024)       | YES  |     | NULL                |       |#具体SQL语句
| trx_operation_state        | varchar(64)         | YES  |     | NULL                |       |#事务当前操作状态
| trx_tables_in_use          | bigint(21) unsigned | NO   |     | 0                   |       |#事务中有多少个表被使用
| trx_tables_locked          | bigint(21) unsigned | NO   |     | 0                   |       |#事务拥有多少个锁
| trx_lock_structs           | bigint(21) unsigned | NO   |     | 0                   |       |#
| trx_lock_memory_bytes      | bigint(21) unsigned | NO   |     | 0                   |       |#事务锁住的内存大小（B）
| trx_rows_locked            | bigint(21) unsigned | NO   |     | 0                   |       |#事务锁住的行数
| trx_rows_modified          | bigint(21) unsigned | NO   |     | 0                   |       |#事务更改的行数
| trx_concurrency_tickets    | bigint(21) unsigned | NO   |     | 0                   |       |#事务并发票数
| trx_isolation_level        | varchar(16)         | NO   |     |                     |       |#事务隔离级别
| trx_unique_checks          | int(1)              | NO   |     | 0                   |       |#是否唯一性检查
| trx_foreign_key_checks     | int(1)              | NO   |     | 0                   |       |#是否外键检查
| trx_last_foreign_key_error | varchar(256)        | YES  |     | NULL                |       |#最后的外键错误
| trx_adaptive_hash_latched  | int(1)              | NO   |     | 0                   |       |#
| trx_adaptive_hash_timeout  | bigint(21) unsigned | NO   |     | 0                   |       |#
+—————————-+———————+——+—–+———————+——-+
22 rows in set (0.01 sec)

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

3.1 使用show processlist查看

3.2 直接使用show engine innodb status查看


------------  
TRANSACTIONS  
------------  
Trx id counter 4131  
Purge done for trx's n:o < 4119 undo n:o < 0 state: running but idle  
History list length 126  
LIST OF TRANSACTIONS FOR EACH SESSION:  
---TRANSACTION 0, not started  
MySQL thread id 2, OS thread handle 0x7f953ffff700, query id 115 localhost root init  
show engine innodb status  
---TRANSACTION 4130, ACTIVE 41 sec starting index read  
mysql tables in use 1, locked 1  
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)  
MySQL thread id 4, OS thread handle 0x7f953ff9d700, query id 112 localhost root updating  
delete from emp where empno=7788  
------- TRX HAS BEEN WAITING 41 SEC FOR THIS LOCK TO BE GRANTED:   ## 等待了41s  
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4130 lock_mode X locks rec but not gap waiting  
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0  ## 线程4在等待往test.emp中的主键上加X锁，page num=3  
 0: len 4; hex 80001e6c; asc    l;;  
 1: len 6; hex 000000001018; asc       ;;  
 2: len 7; hex 91000001420084; asc     B  ;;  
 3: len 5; hex 53434f5454; asc SCOTT;;  
 4: len 7; hex 414e414c595354; asc ANALYST;;  
 5: len 4; hex 80001d8e; asc     ;;  
 6: len 4; hex 208794f0; asc     ;;  
 7: len 4; hex 80000bb8; asc     ;;  
 8: SQL NULL;  
 9: len 4; hex 80000014; asc     ;;  
 
---TRANSACTION 4129, ACTIVE 45 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 7, OS thread handle 0x7f953ff6c700, query id 111 localhost root updating
update emp set sal=3500 where empno=7788
------- TRX HAS BEEN WAITING 45 SEC FOR THIS LOCK TO BE GRANTED:   ## 等待了45s
RECORD LOCKS space id 16 page no 3 n bits 88 index PRIMARY of table test.emp trx id 4129 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0  ## 线程7在等待往test.emp中的主键上加X锁，page num=3
0: len 4; hex 80001e6c; asc    l;;
1: len 6; hex 000000001018; asc       ;;
2: len 7; hex 91000001420084; asc     B  ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc     ;;
6: len 4; hex 208794f0; asc     ;;
7: len 4; hex 80000bb8; asc     ;;
8: SQL NULL;
9: len 4; hex 80000014; asc     ;;
 
---TRANSACTION 4128, ACTIVE 51 sec
2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 3, OS thread handle 0x7f953ffce700, query id 110 localhost root cleaning up

我们知道，主要根因还是thread=3引起的，但从innodb status中却无法分析得到这个结果。

从上面来看，线程4和线程7都在等待往test.emp中的主键上加X锁，page num=3，但是线程7等待的时间为45s，而线程4等待的时间为41s，是较线程7之后申请的锁，所以可以判断是线程7阻塞了线程4。至于线程7为什么出现等待，这里分析不到根因。

3.3 使用mysqladmin debug查看

# mysqladmin -S /tmp/mysql3306.sock debug

然后在error日志中，会看到：

Thread database.table_name          Locked/Waiting        Lock_type

3 test.t3 Locked - read Low priority read lock
7 test.emp Locked - write High priority write lock

这种方法中，能找到线程ID=3和7是阻塞者，但还是不太准确，判断不出来线程7也是被线程ID=3阻塞的。

3.4 使用innodb_lock_monitor来获取阻塞锁线程

复制代码


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)

复制代码

说明：这个在5.6中有一个warning，但不影响使用。

然后再使用show engine innodb status查看：

复制代码


------------  
TRANSACTIONS  
------------  
Trx id counter 4667  
Purge done for trx's n:o < 4659 undo n:o < 0 state: running but idle  
History list length 138  
LIST OF TRANSACTIONS FOR EACH SESSION:  
---TRANSACTION 0, not started  
MySQL thread id 9, OS thread handle 0x7f813c5f7700, query id 152 localhost root init  
show engine innodb status  
---TRANSACTION 4663, ACTIVE 78 sec starting index read  
mysql tables in use 1, locked 1  
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)  
MySQL thread id 4, OS thread handle 0x7f813c628700, query id 149 localhost root updating  
delete from emp where empno=7788  
------- TRX HAS BEEN WAITING 78 SEC FOR THIS LOCK TO BE GRANTED:   ## 等待了78s  
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4663 lock_mode X locks rec but not gap waiting  
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0  ## 线程4在等待往test.emp中的主键上加X锁，page num=3  
 0: len 4; hex 80001e6c; asc    l;;  
 1: len 6; hex 000000001018; asc       ;;  
 2: len 7; hex 91000001420084; asc     B  ;;  
 3: len 5; hex 53434f5454; asc SCOTT;;  
 4: len 7; hex 414e414c595354; asc ANALYST;;  
 5: len 4; hex 80001d8e; asc     ;;  
 6: len 4; hex 208794f0; asc     ;;  
 7: len 4; hex 80000bb8; asc     ;;  
 8: SQL NULL;  
 9: len 4; hex 80000014; asc     ;;  
  
------------------  
TABLE LOCK table `test`.`emp` trx id 4663 lock mode IX   ## 在给主键行上加X锁之前，先要在表上加意向锁IX  
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4663 lock_mode X locks rec but not gap waiting  
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0  
 0: len 4; hex 80001e6c; asc    l;;  
 1: len 6; hex 000000001018; asc       ;;  
 2: len 7; hex 91000001420084; asc     B  ;;  
 3: len 5; hex 53434f5454; asc SCOTT;;  
 4: len 7; hex 414e414c595354; asc ANALYST;;  
 5: len 4; hex 80001d8e; asc     ;;  
 6: len 4; hex 208794f0; asc     ;;  
 7: len 4; hex 80000bb8; asc     ;;  
 8: SQL NULL;  
 9: len 4; hex 80000014; asc     ;;  
  
---TRANSACTION 4662, ACTIVE 81 sec starting index read  
mysql tables in use 1, locked 1  
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)  
MySQL thread id 7, OS thread handle 0x7f813c5c6700, query id 148 localhost root updating  
update emp set sal=3500 where empno=7788  
------- TRX HAS BEEN WAITING 81 SEC FOR THIS LOCK TO BE GRANTED:  ## 等待了81s  
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4662 lock_mode X locks rec but not gap waiting  
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0  ## 线程7在等待往test.emp中的主键上加X锁，page num=3  
 0: len 4; hex 80001e6c; asc    l;;  
 1: len 6; hex 000000001018; asc       ;;  
 2: len 7; hex 91000001420084; asc     B  ;;  
 3: len 5; hex 53434f5454; asc SCOTT;;  
 4: len 7; hex 414e414c595354; asc ANALYST;;  
 5: len 4; hex 80001d8e; asc     ;;  
 6: len 4; hex 208794f0; asc     ;;  
 7: len 4; hex 80000bb8; asc     ;;  
 8: SQL NULL;  
 9: len 4; hex 80000014; asc     ;;  
  
------------------  
TABLE LOCK table `test`.`emp` trx id 4662 lock mode IX   ## 在给主键行上加X锁之前，先要在表上加意向锁IX  
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4662 lock_mode X locks rec but not gap waiting  
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0  
 0: len 4; hex 80001e6c; asc    l;;  
 1: len 6; hex 000000001018; asc       ;;  
 2: len 7; hex 91000001420084; asc     B  ;;  
 3: len 5; hex 53434f5454; asc SCOTT;;  
 4: len 7; hex 414e414c595354; asc ANALYST;;  
 5: len 4; hex 80001d8e; asc     ;;  
 6: len 4; hex 208794f0; asc     ;;  
 7: len 4; hex 80000bb8; asc     ;;  
 8: SQL NULL;  
 9: len 4; hex 80000014; asc     ;;  
  
---TRANSACTION 4615, ACTIVE 1579 sec, thread declared inside InnoDB 1222  
mysql tables in use 2, locked 0  
2 lock struct(s), heap size 360, 1 row lock(s)  
MySQL thread id 3, OS thread handle 0x7f813c659700, query id 147 localhost root Sending data  
select count(*) from t3 a,t3 b   ## 这是线程3当前正在执行的SQL  
Trx read view will not see trx with id >= 4662, sees < 4659  
TABLE LOCK table `test`.`emp` trx id 4615 lock mode IX  ## 线程3中正在拥有表上的意向IX锁，并且有test.emp表上主键的行级X锁，page num=3  
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4615 lock_mode X locks rec but not gap  
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0  
 0: len 4; hex 80001e6c; asc    l;;  
 1: len 6; hex 000000001018; asc       ;;  
 2: len 7; hex 91000001420084; asc     B  ;;  
 3: len 5; hex 53434f5454; asc SCOTT;;  
 4: len 7; hex 414e414c595354; asc ANALYST;;  
 5: len 4; hex 80001d8e; asc     ;;  
 6: len 4; hex 208794f0; asc     ;;  
 7: len 4; hex 80000bb8; asc     ;;  
 8: SQL NULL;  
 9: len 4; hex 80000014; asc     ;;

复制代码

为什么线程3当前执行的是一个select t3表操作，但却锁住了test.emp表上page num=3？
有可能是线程3之前对test.emp表的操作事务没有及时提交导致。
所以得出：线程3阻塞了线程7，而线程7又阻塞了线程4，所以根因就是线程3，让线程3尽快提交或是kill掉即可。

3.5、查看表锁的情况：

复制代码


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

复制代码

3.6、查看InnoDB_row_lock状态变量来分析系统上的行锁的争夺情况：

复制代码


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)
 
mysql>

复制代码

4. 结论

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。

参考：http://blog.csdn.net/hw_libo/article/details/39080809

如果简单看的话

第一种：

1.查询是否锁表

show OPEN TABLES where In_use > 0;

2.查询进程（如果您有SUPER权限，您可以看到所有线程。否则，您只能看到您自己的线程）

show processlist

3.杀死进程id（就是上面命令的id列）

kill id

第二种：

1.查看下在锁的事务

SELECT * FROM INFORMATION_SCHEMA.INNODB_TRX;

2.杀死进程id（就是上面命令的trx_mysql_thread_id列）

kill 线程ID

例子：

查出死锁进程：SHOW PROCESSLIST

其它关于查看死锁的命令：

1：查看当前的事务
SELECT * FROM INFORMATION_SCHEMA.INNODB_TRX;

2：查看当前锁定的事务

SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCKS;

3：查看当前等锁的事务
SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCK_WAITS;

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mysql 查看死锁和去除死锁_empty set, 1 warning (0.00 sec)

1、查询进程

查看锁阻塞线程信息

3.5、 查看表锁的情况：

3.6、查看InnoDB_row_lock状态变量来分析系统上的行锁的争夺情况：

4. 结论

3.5、查看表锁的情况：