mysql禁用autocommit,以及遇到的问题
mysql禁用autocommit,以及遇到的问题mysql的autocommit（自动提交）默认是开启，其对mysql的性能有一定影响，举个例子来说，如果你插入了1000条数据，mysql会commit1000次的，如果我们把autocommit关闭掉，通过程序来控制，只要一次commit就可以了。
1,我们可以通过set来设置autocommit
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[*]mysql> set global init_connect="set autocommit=0";//提示你用权限更高的财户来设置
[*]ERROR 1227 (42000): Access denied; you need (at least one of) the SUPER privilege(s) for this operation
[*]mysql> set autocommit=0;
[*]Query OK, 0 rows affected (0.00 sec)
[*]
[*]mysql> select @@autocommit; //查看一下autocommit的设置
[*]+--------------+
[*]| @@autocommit |
[*]+--------------+
[*]| 0 |
[*]+--------------+
[*]1 row in set (0.00 sec)
mysql> set global init_connect="set autocommit=0";//提示你用权限更高的财户来设置
ERROR 1227 (42000): Access denied; you need (at least one of) the SUPER privilege(s) for this operation
mysql> set autocommit=0;
Query OK, 0 rows affected (0.00 sec)
mysql> select @@autocommit; //查看一下autocommit的设置
+--------------+
| @@autocommit |
+--------------+
| 0 |
+--------------+
1 row in set (0.00 sec)
2,我们可以修改mysql的配置文件my.cnf来关闭autocommit
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[*]
[*]init_connect='SET autocommit=0'//在mysqld里面加上这些内容
init_connect='SET autocommit=0'//在mysqld里面加上这些内容
用第二种方法关，有一点要注意，连接mysql用户的权限不能大于启动mysql的用户的权限，不然init_connect='SET autocommit=0'根本不会启作用，也不会报任何错误，汗一个先。看以下实例
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[*]zhangy@ubuntu:~$ mysql -umysql
[*]Welcome to the MySQL monitor.Commands end with ; or \g.
[*]Your MySQL connection id is 1
[*]Server version: 5.5.2-m2-log Source distribution
[*]
[*]Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
[*]
[*]mysql> select @@autocommit; //mysql是启动用户，关闭autocommit成功
[*]+--------------+
[*]| @@autocommit |
[*]+--------------+
[*]| 0 |
[*]+--------------+
[*]1 row in set (0.00 sec)
[*]
[*]mysql> Ctrl-C -- exit!
[*]Aborted
[*]zhangy@ubuntu:~$ mysql -uroot
[*]Welcome to the MySQL monitor.Commands end with ; or \g.
[*]Your MySQL connection id is 2
[*]Server version: 5.5.2-m2-log Source distribution
[*]
[*]Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
[*]
[*]mysql> select @@autocommit; //用root财户启动，不成功。
[*]+--------------+
[*]| @@autocommit |
[*]+--------------+
[*]| 1 |
[*]+--------------+
[*]1 row in set (0.00 sec)
zhangy@ubuntu:~$ mysql -umysql
Welcome to the MySQL monitor.Commands end with ; or \g.
Your MySQL connection>
Server version: 5.5.2-m2-log Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> select @@autocommit; //mysql是启动用户，关闭autocommit成功
+--------------+
| @@autocommit |
+--------------+
| 0 |
+--------------+
1 row in set (0.00 sec)
mysql> Ctrl-C -- exit!
Aborted
zhangy@ubuntu:~$ mysql -uroot
Welcome to the MySQL monitor.Commands end with ; or \g.
Your MySQL connection>
Server version: 5.5.2-m2-log Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> select @@autocommit; //用root财户启动，不成功。
+--------------+
| @@autocommit |
+--------------+
| 1 |
+--------------+
1 row in set (0.00 sec)
这个会不会是mysql的bug呢？我在网上找了找这方面的问题，还真有。部分内容如下：
If a user has SUPER privilege, init_connect will not execute
(otherwise if init_connect will a wrong query no one can connect to server).
Note, if init_connect is a wrong query, the connection is closing without any errors
and next command will clause 'lost connection' error.
里面有一点说的很清楚If a user has SUPER privilege, init_connect will not execute，如果用户有更高级的权限，init_connect根本不会执行。
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