MYSQL—GTID主从备份
GITD定义
1.全局事物标识（global transaction identifieds)
2.GTID事物是唯一性一个事务对应一个GTID
3.一个GTID在服务器上只执行一次，避免重复执行，导致数据混乱
4.使用master_auto_postion=1的方式自动匹配GTID断点进行复制
5.mysql-5.6.5开始支持，mysql-5.6.10开始完善
GTID = source_id:transation_id
GTID的组成部分
server_uuid:后面是一个序列号
uuid:每个mysql实例的唯一ID，由于会传递到slave,所以可以理解为源ID
Sequence number:在每台mysql服务器上都是从1开始自增长的序列，一个数值对应一个事务。
GTID比传统复制的优势
1.更容易实现failover,不用一千那样在需要找log_file和log_pos.
2.更简单的搭建主从复制
3.更加安全
4.GTID是连续没有空洞的，因此主从库出现数据冲突时，可以用添加空事物的方式进行跳过。
GTID工作原理
1.master更新数据时，会在事务前产生GTID，一同记录到binlog日志中
2.slave端的I/O线程将变更的binlog，写入到本地的relay log中
3.sql线程从reloy log中获取GTID，然后对比slave端的binlog是否有记录
4.如果有记录，说明该GTID的事务已经执行，slave会忽略
5.如果没有记录，slave就好从relay log中执行该GTID的事务，并记录到binglog
6.在解析过程中会判断是否有主键，如果没有就用二级索引，如果没有就用全部扫描。
MYSQL基于GTID的主从备份
准备两台虚拟机，分别两台都安装MySQL，步骤略。详情参照MySQL主从配置这篇文章。
| 数据库角色 | IP | 应用与系统版本 |
|---|---|---|
| 主数据库 | 192.168.228.23 | centos7 |
| 从数据库 | 192.168.228.30 | centos7 |
在主数据库服务器修改/etc/my.cnf配置文件
[root@yxr ~]# vim /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve
#GTID
server-id=23 //主服务器id（可以修改成自己的主机，方便区分）
gtid-mode=on //开启gtid模式
enforce-gtid-consistency=on //强制gtid一致性，开启后对于特定create table不被支持
#binlog
log_bin=master-binlog
log-slave-updates=1
binlog_format=row //强烈建议，其他格式可能导致数据不一致
#relay log
skip_slave_start=1
重启mysql服务
[root@yxr ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL.. SUCCESS!
[root@yxr ~]# ss -antl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
LISTEN 0 80 :::3306 :::*
在主数据库上创建一个同步账号授权给从数据库使用
[root@yxr ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.22-log MySQL Community Server (GPL)
Copyright (c) 2000, 2018, 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> create user 'repl'@'192.168.228.30' identified by '123456';
Query OK, 0 rows affected (0.01 sec)
mysql> grant replication slave on *.* to 'repl'@'192.168.228.30';
Query OK, 0 rows affected (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql> exit
Bye重新开一个终端，给主数据库上读锁（避免备份途中与其他人在写入导致数据同步的不一致）
[root@yxr ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.22-log MySQL Community Server (GPL)
Copyright (c) 2000, 2018, 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> flush tables with read lock;
Query OK, 0 rows affected (0.00 sec)
(注意：此锁表的终端必须在备份完成以后才能退出)在从数据库服务器操作如下
修改配置文件
[root@arongya ~]# vim /etc/my.cnf
[root@arongya ~]# cat /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve
#GTID 添加以下内容
gtid_mode=on //控制开启/关闭GTID模式
enforce_gtid_consistency=on
server_id=30
#binlog
log-bin=slave-binlog
log-slave-updates=1
binlog-format=row //强制建议，其他格式可能导致数据不一致
#relay log
skip-slave-start=1重启服务
[root@arongya ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL..... SUCCESS! 配置并启动主从复制,首先先进入mysql数据库
mysql> change master to
-> master_host='192.168.228.23',
-> master_user='repl',
-> master_password='123456',
-> master_port=3306,
-> master_auto_position=1;
Query OK, 0 rows affected, 2 warnings (0.06 sec)
mysql> start slave;
Query OK, 0 rows affected (0.06 sec)
查看从服务器的状态：
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.228.23
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: master-binlog.000001
Read_Master_Log_Pos: 773
Relay_Log_File: arongya-relay-bin.000002
Relay_Log_Pos: 994
Relay_Master_Log_File: master-binlog.000001
Slave_IO_Running: Yes //这里必须与我的一致为yes
Slave_SQL_Running: Yes //这里必须与我的一致为yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 773
Relay_Log_Space: 1203
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 128
Master_UUID: 6be5e744-b3c9-11e8-a134-000c29989243
Master_Info_File: /opt/data/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set: 6be5e744-b3c9-11e8-a134-000c29989243:1-3
Executed_Gtid_Set: 6be5e744-b3c9-11e8-a134-000c29989243:1-3
Auto_Position: 1
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)
ERROR:
No query specified解除主库的锁表状态，直接退出交互式界面即可
mysql> quit
Bye
验证,在主库创建名为yaoxiaorong的数据库，并添加内容，插入数据
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
mysql> create database yaoxiaorong;
Query OK, 1 row affected (0.02 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| yaoxiaorong |
+--------------------+
5 rows in set (0.00 sec)
mysql> use yaoxiaorong;
Database changed
mysql> create table student (id int not null,name varchar(100) not null,age tinyint);
Query OK, 0 rows affected (0.10 sec)
mysql> show tables;
+-----------------------+
| Tables_in_yaoxiaorong |
+-----------------------+
| student |
+-----------------------+
1 row in set (0.00 sec)
mysql> insert into student(id,name,age)values(1,'tom',20),(2,'jerry',28),(3,'sean',25);
Query OK, 3 rows affected (0.11 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> select * from student;
+----+-------+------+
| id | name | age |
+----+-------+------+
| 1 | tom | 20 |
| 2 | jerry | 28 |
| 3 | sean | 25 |
+----+-------+------+
3 rows in set (0.00 sec)在从数据库服务器上查看是否同步存在yaoxiaorong库
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| yaoxiaorong |
+--------------------+
5 rows in set (0.04 sec)
mysql> use yaoxiaorong;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from student;
+----+-------+------+
| id | name | age |
+----+-------+------+
| 1 | tom | 20 |
| 2 | jerry | 28 |
| 3 | sean | 25 |
+----+-------+------+
3 rows in set (0.00 sec)