概述

一般生产环境都需要定期去做一次MySQL数据库主备切换演练，这里简单记录一下，后面再演示一下备份恢复的一些演练工作。

1、查看主库状态

show processlist;
Master has sent all binlog to slave; waiting for binlog to be updated
show master status G

2、查看从库状态

show processlist;
show slave status G

3、从库停止 IO_THREAD 线程

stop slave IO_THREAD;
show processlist;
show slave status G

4、从库切换为主库

stop slave;
reset master;
reset slave all;
show master status G

5、激活帐户

SELECT DISTINCT CONCAT('User: ''',user,'''@''',host,''';') AS query FROM mysql.user;
GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%' IDENTIFIED BY 'xxx;
FLUSH PRIVILEGES;

6、切换原有主库为从库(原有主库执行)

reset master;
reset slave all;
CHANGE MASTER TO
MASTER_HOST='1xxx',
MASTER_USER='repl',
MASTER_PASSword='xxx,
MASTER_PORT=3306,
MASTER_LOG_FILE='mysql-bin.000001',
MASTER_LOG_POS=589;

7、检查主库

SHOW PROCESSLIST;
show master status G

8、启动从库

SHOW PROCESSLIST;
start slave;
show slave status G

9、MySQL主从测试

9.1插入数据

9.1.1创建测试表并插入数据

mysql> create table test123(id int(4));
Query OK, 0 rows affected (0.01 sec)
mysql> insert into test123 values(1);
Query OK, 1 row affected (0.00 sec)
mysql> insert into test123 values(2);
Query OK, 1 row affected (0.00 sec)
mysql> insert into test123 values(3);
Query OK, 1 row affected (0.00 sec)
mysql> insert into test123 values(4);
Query OK, 1 row affected (0.00 sec)

9.1.2从库查询：

9.2 删除数据

9.2.1主库删除表：

mysql> drop table test123;

9.2.2 从库查询：