MySQL innodb行锁测试

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MySQL innodb存储引擎使用与oracle相同的行锁机制,对如何查看系统中存在的行锁情况在下面的实验中,将可以看到。下面是测试过程:
session 1:更新记录
[coolcode]
mysql> set autocommit=off;
Query OK, 0 rows affected (0.01 sec)
mysql> update t1 set email='test@test.com' where id=0;
Query OK, 4 rows affected (0.00 sec)
Rows matched: 4  Changed: 4  Warnings: 0
[/coolcode]
session 2也更新相同的记录,出现等待
[coolcode]
mysql> set autocommit=off;
Query OK, 0 rows affected (0.00 sec)
mysql> update t1 set email='abc' where id=0;
[/coolcode]
session 3:查看系统等待事件:
mysql> show status like '%lock%';
+-------------------------------+---------+
| Variable_name                 | Value   |
+-------------------------------+---------+
| Com_lock_tables               | 0       |
| Com_unlock_tables             | 0       |
| Innodb_row_lock_current_waits | 1       | --这里
| Innodb_row_lock_time          | 0       |
| Innodb_row_lock_time_avg      | 0       |
| Innodb_row_lock_time_max      | 0       |
| Innodb_row_lock_waits         | 1       |
| Key_blocks_not_flushed        | 0       |
| Key_blocks_unused             | 14497   |
| Key_blocks_used               | 0       |
| Qcache_free_blocks            | 1       |
| Qcache_total_blocks           | 1       |
| Table_locks_immediate         | 2070991 |
| Table_locks_waited            | 2       |
+-------------------------------+---------+
14 rows in set (0.01 sec)
session 1:提交记录
[coolcode]
mysql> commit;
Query OK, 0 rows affected (0.01 sec)
[/coolcode]
session 2:update立刻完成
[coolcode]
mysql> update t1 set email='abc' where id=0;
Query OK, 4 rows affected (2 min 43.44 sec)
Rows matched: 4  Changed: 4  Warnings: 0
[/coolcode]
session 3:再次查看系统等待事件
[coolcode]
mysql> show status like '%lock%';
+-------------------------------+---------+
| Variable_name                 | Value   |
+-------------------------------+---------+
| Com_lock_tables               | 0       |
| Com_unlock_tables             | 0       |
| Innodb_row_lock_current_waits | 0       |  --这里为0
| Innodb_row_lock_time          | 163436  |
| Innodb_row_lock_time_avg      | 163436  |
| Innodb_row_lock_time_max      | 163436  |
| Innodb_row_lock_waits         | 1       |
| Key_blocks_not_flushed        | 0       |
| Key_blocks_unused             | 14497   |
| Key_blocks_used               | 0       |
| Qcache_free_blocks            | 1       |
| Qcache_total_blocks           | 1       |
| Table_locks_immediate         | 2070991 |
| Table_locks_waited            | 2       |
+-------------------------------+---------+
14 rows in set (0.01 sec)
[/coolcode]
查询会话session 1,session 2的连接ID
[coolcode]
session 1:
mysql> status;
--------------
mysql  Ver 12.22 Distrib 4.0.24, for pc-solaris2.10 (i386)
Connection id:          15
session 2:
mysql> status;
--------------
mysql  Ver 12.22 Distrib 4.0.24, for pc-solaris2.10 (i386)
Connection id:          13
[/coolcode]
在上面的session 1尚没有提交的时候,可以执行下列命令,查看一些事务阻塞信息
[coolcode]
mysql> show innodb status\G;
------------
TRANSACTIONS
------------
Trx id counter 0 3852351
Purge done for trx's n:o < 0 3852350 undo n:o < 0 0
History list length 11
Total number of lock structs in row lock hash table 7
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0 0, not started, OS thread id 15
MySQL thread id 18, query id 2071119 localhost root
show innodb status
---TRANSACTION 0 3852350, ACTIVE 6 sec, OS thread id 14 starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 320
MySQL thread id 13, query id 2071118 localhost test Updating      --这里可以看到等待者
update t1 set email='abc' where id=0          --这里可以看到等待者正在执行的SQL
------- TRX HAS BEEN WAITING 6 SEC FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 0 page no 32782 n bits 1056 index `idx_t1_id` of table `dc_test/t1` trx id 0 3852350 lock_mode X waiting
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 0
0: len 4; hex 80000000; asc     ;; 1: len 6; hex 00000196fe5d; asc      ];;
------------------
---TRANSACTION 0 3852348, ACTIVE 391 sec, OS thread id 12
7 lock struct(s), heap size 1024, undo log entries 4
MySQL thread id 15, query id 2071117 localhost test
[/coolcode]
当出现行锁时,谁等待谁?在哪里得到此信息,如何kill阻塞者,不知道在Mysql数据库里怎么操作?