怎么使用innodb行鎖

本篇內(nèi)容主要講解“怎么使用innodb行鎖”，感興趣的朋友不妨來(lái)看看。本文介紹的方法操作簡(jiǎn)單快捷，實(shí)用性強(qiáng)。下面就讓小編來(lái)帶大家學(xué)習(xí)“怎么使用innodb行鎖”吧!

三種級(jí)別

record lock  鎖住某一行記錄  

gap lock     鎖住某一段范圍中的記錄 

next key lock 是前兩者效果的疊加
實(shí)驗(yàn)環(huán)境
mysql> select @@tx_isolation;
+-----------------+
| @@tx_isolation  |
+-----------------+
| REPEATABLE-READ |
+-----------------+
1 row in set (0.00 sec)
mysql> select * from t;
+------+
| id   |
+------+
|    2 |
|    8 |
|   19 |
|   22 |
+------+
mysql> create index t_ind on t(id);
Query OK, 0 rows affected (8.52 sec)
 同時(shí)打開兩個(gè)會(huì)話，并打開事物
會(huì)話一
mysql> start transaction;
Query OK, 0 rows affected (0.00 sec)
mysql> delete from t where id=19;
Query OK, 1 row affected (0.00 sec)
會(huì)話二
mysql> start transaction;
Query OK, 0 rows affected (0.00 sec)
mysql> insert into t values(55);
Query OK, 1 row affected (0.00 sec)
mysql> insert into t values(10);
^C^C -- query aborted
ERROR 1317 (70100): Query execution was interrupted
mysql> 
mysql> insert into t values(1);
Query OK, 1 row affected (0.00 sec)

mysql> insert into t values(12);
^C^C -- query aborted
ERROR 1317 (70100): Query execution was interrupted
mysql> 
會(huì)話二說明8-22之間被鎖住了，無(wú)法插入數(shù)據(jù).這就是gap lock                                                      

取消gap lock
修改事物的隔離級(jí)別到READ COMMITTED                                                                               

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