MySQL Study之--MySQL关闭自动commit（autocommit）
MySQL Study之--MySQL关闭自动commit（autocommit）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
# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.Commands end with ; or \g.
Your MySQL connection>
Server version: 5.6.25-73.1 Percona Server (GPL),> 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> Query OK, 0 rows affected (0.00 sec)
mysql> grant all on prod.* to 'tom'@'localhost'>
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：
# mysql -u tom -p
Enter password:
Welcome to the MySQL monitor.Commands end with ; or \g.
Your MySQL connection>
Server version: 5.6.25-73.1 Percona Server (GPL),> 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> useprod;
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;
+------+------+
|> +------+------+
| 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：
# service mysql stop
Shutting down MySQL (Percona Server)....
# service mysql start
Starting MySQL (Percona Server).....
# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.Commands end with ; or \g.
Your MySQL connection>
Server version: 5.6.25-73.1 Percona Server (GPL),> 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：
# vi /etc/my.cnf
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
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：
# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.Commands end with ; or \g.
Your MySQL connection>
Server version: 5.6.25-73.1 Percona Server (GPL),> 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>
Server version: 5.6.25-73.1 Percona Server (GPL),> 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
+-------------------------------------------+-------+
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