MySQL Study之--MySQL关闭自动commit（autocommit）

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   对于mysql来讲，在事务处理时，默认是在动提交的（autocommit），以下方法可以自动关闭autocommit；案例分析：
1、在mysql登录环境下修改
[iyunv@mysql2 soft]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.6.25-73.1 Percona Server (GPL), Release 73.1, Revision 07b797f
Copyright (c) 2009-2015 Percona LLC and/or its affiliates
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.02 sec)

mysql> select version();
+-------------+
| version()   |
+-------------+
| 5.6.25-73.1 |
+-------------+
1 row in set (0.00 sec)

mysql> show variables like '%autocommit%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| autocommit    | ON    |                ；；默认autocommit是开启的
+---------------+-------+
1 row in set (0.03 sec)

在当前session关闭autocommit：
mysql> set @@session.autocommit=0;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%autocommit%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| autocommit    | OFF   |
+---------------+-------+
1 row in set (0.00 sec)

在global级别关闭autocommit：
mysql> set @@global.autocommit=0;
Query OK, 0 rows affected (0.01 sec)

创建普通用户：
mysql> create user tom identified by 'tom';
Query OK, 0 rows affected (0.00 sec)

mysql> grant all on prod.* to 'tom'@'localhost' identified by 'tom';
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

普通用户登录：
[iyunv@mysql2 ~]# mysql -u tom -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.6.25-73.1 Percona Server (GPL), Release 73.1, Revision 07b797f
Copyright (c) 2009-2015 Percona LLC and/or its affiliates
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> use mysql;
ERROR 1044 (42000): Access denied for user 'tom'@'localhost' to database 'mysql'
mysql> use  prod;
Database changed
mysql> show tables;
Empty set (0.00 sec)

mysql> show variables like '%commit%';
+-------------------------------------------+-------+
| Variable_name                             | Value |
+-------------------------------------------+-------+
| autocommit                                | OFF   |
| binlog_order_commits                      | ON    |
| innodb_api_bk_commit_interval             | 5     |
| innodb_commit_concurrency                 | 0     |
| innodb_flush_log_at_trx_commit            | 1     |
| innodb_use_global_flush_log_at_trx_commit | ON    |
+-------------------------------------------+-------+
6 rows in set (0.00 sec)

创建测试表：
mysql> create table t1(id int,name varchar(10));
Query OK, 0 rows affected (0.15 sec)

mysql> insert into t1 values (10,'tom');
Query OK, 1 row affected (0.00 sec)

mysql> select * from t1;
+------+------+
| id   | name |
+------+------+
|   10 | tom
|
+------+------+
1 row in set (0.00 sec)

事务回滚：
mysql> rollback;
Query OK, 0 rows affected (0.02 sec)

mysql> select * from t1;
Empty set (0.00 sec)

2、在mysql service重启后
mysql server 重启后：
[iyunv@mysql2 ~]# service mysql stop
Shutting down MySQL (Percona Server)....[  OK  ]
[iyunv@mysql2 ~]# service mysql start
Starting MySQL (Percona Server).....[  OK  ]
[iyunv@mysql2 ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.25-73.1 Percona Server (GPL), Release 73.1, Revision 07b797f
Copyright (c) 2009-2015 Percona LLC and/or its affiliates
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show variables like '%commit%';
+-------------------------------------------+-------+
| Variable_name                             | Value |
+-------------------------------------------+-------+
| autocommit                                | ON    |             ；；autocommit仍然是开启状态
+-------------------------------------------+-------+
6 rows in set (0.01 sec)

编辑/etc/my.cnf文件：
[iyunv@mysql2 ~]# vi /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
init_connect='set autocommit=0'                                    ；；用户登录时，关闭autocommit
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
explicit_defaults_for_timestamp=true
innodb_buffer_pool_size = 128M
join_buffer_size = 128M
sort_buffer_size = 2M
read_rnd_buffer_size = 2M

用户登录查看：
[iyunv@mysql2 ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.25-73.1 Percona Server (GPL), Release 73.1, Revision 07b797f
Copyright (c) 2009-2015 Percona LLC and/or its affiliates
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show variables like '%commit%';
+-------------------------------------------+-------+
| Variable_name                             | Value |
+-------------------------------------------+-------+
| autocommit                                | ON    |                ；；root用户不受影响（为安全起见）

mysql> system mysql -u tom -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.25-73.1 Percona Server (GPL), Release 73.1, Revision 07b797f
Copyright (c) 2009-2015 Percona LLC and/or its affiliates
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show variables like '%commit%';
+-------------------------------------------+-------+
| Variable_name                             | Value |
+-------------------------------------------+-------+
| autocommit                                | OFF   |                ；；普通用户，autocommit已被关闭
+-------------------------------------------+-------+