MySQL 复制
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概述：
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MySQL Replication：
1.主从复制的目的和架构
★Master/Slave（主/从）
Master: write/read
Slaves: read
★主从复制的目的
冗余：promte（提升为主），异地灾备
负载均衡：转移一部分“读”请求；
支援安全的备份操作；
测试；
...
★复制的方式：
☉同步复制：
所谓的同步复制，意思是master的变化，必须等待slave-1,slave-2,...,slave-n完成后才能返回。这样，显然不可取，也不是MYSQL复制的默认设置。比如，在WEB前端页面上，用户增加了条记录，需要等待很长时间。
☉异步复制：
如同AJAX请求一样。master只需要完成自己的数据库操作即可。至于slaves是否收到二进制日志，是否完成操作，不用关心。MYSQL的默认设置。
☉半同步复制：
master只保证slaves中的一个操作成功，就返回，其他slave不管。这个功能，是由google为MYSQL引入的。
★主/从架构：
一主多从；
一从一主；
级联复制；
循环复制；
双主复制；
一从多主：每个主服务器提供不同的数据库；
2.主从复制的工作流程
★整体上来说，复制有3个步骤：
master将改变记录到二进制日志(binary log)中（这些记录叫做二进制日志事件，binary log events）；
slave将master的binary log events拷贝到它的中继日志(relay log)；
slave重做中继日志中的事件，将改变反映它自己的数据。
流程图：
MySQL 复制配置
1.主从复制配置步骤及操作演示
★配置前注意事项：
时间同步；
复制的开始位置：
从0开始；
从备份中恢复到从节点后，启动复制；
主从服务器mysqld程序版本不一致？:可以，但要求从服务器版本要高于主服务器；
★主服务器：
☉配置文件my.cnf
server_id=#
log_bin=log-bin
☉启动服务：
mysql> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'USERNAME'@'HOST' IDENTIFIED BY 'YOUR_PASSWORD';
mysql> FLUSH PRIVILEGES;
★从服务器：
☉配置文件my.cnf
server_id=#
relay_log=relay-log
☉启动服务：
mysql> CHANGE MASTER TO MASTER_HOST='HOST',MASTER_USER='USERNAME',MASTER_PASSWORD='YOUR_PASSWORD',MASTER_LOG_FILE='BINLOG',MASTER_LOG_POS=#;
mysql> START SLAVE [IO_THREAD|SQL_THREAD];
mysql> SHOW SLAVE STATUS;
主从复制时应该注意的问题：
★从服务设定为“只读”；
☉在从服务器启动read_only，但仅对非SUPER权限的用户有效；
☉阻止所有用户：
mysql> FLUSH TABLES WITH READ LOCK;
不建议使用，这样的话从服务器复制的数据就写不到磁盘中了
★尽量确保复制时的事务安全
☉在master节点启用参数：
sync_binlog = ON
//每次提交立即将二进制事件从内存同步到二进制日志中
☉如果用到的是InnoDB存储引擎：
innodb_flush_logs_at_trx_commit=ON //在事务提交时立即刷写日志
innodb_support_xa=ON //支持分布式事务
★从服务器意外中止时尽量避免自动启动复制线程
★从节点：设置参数
sync_master_info=ON
sync_relay_log_info=ON
实验：配置实现主从复制
演示环境：
两台CentOS 7的虚拟主机，一台做为mysql的主服务器，一台作为从服务器；
两台服务器的MySQL的版本均为：mariadb-server-5.5.44-2.el7.centos.x86_64
操作步骤如下：
1.首先在主从节点同步时间，编辑/etc/chrony,添加时间服务器即可，如下：
[root@slave ~]# vim /etc/chrony.conf server 10.1.0.1 iburst [root@master ~]# date;ssh 10.1.249.103 'date' //主从服务器同步时间如下 Sun Dec 4 12:05:15 CST 2016 Sun Dec 4 12:05:15 CST 2016
2.编辑主节点服务器的配置文件/etc/my.cnf,并启动服务，如下：
[root@master ~]# vim /etc/my.cnf [mysqld] skip_name_resolve = ON innodb_file_per_table = ON log_bin=master-log # 添加启动二进制日志文件 server-id=1 # server-id #================================================================================================= [root@master ~]# systemctl start mariadb.service # 启动服务 [root@master ~]# ss -tnl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 25 *:514 *:* LISTEN 0 50 *:3306 *:* LISTEN 0 128 *:22 *:* LISTEN 0 128 127.0.0.1:631 *:* LISTEN 0 100 127.0.0.1:25 *:* #================================================================================================== [root@master ~]# ll /var/lib/mysql/ # 查看数据库目录 total 132012 -rw-rw---- 1 mysql mysql 16384 Dec 3 21:47 aria_log.00000001 -rw-rw---- 1 mysql mysql 52 Dec 3 21:47 aria_log_control drwx------ 2 mysql mysql 4096 Dec 3 14:48 hellodb -rw-r----- 1 mysql mysql 18874368 Dec 3 21:47 ibdata1 -rw-r----- 1 mysql mysql 50331648 Dec 4 14:14 ib_logfile0 -rw-r----- 1 mysql mysql 50331648 Dec 3 14:44 ib_logfile1 -rw-rw---- 1 mysql mysql 15530898 Dec 3 21:47 master-log.000001 # 二进制日志文件 -rw-rw---- 1 mysql mysql 40 Dec 4 14:14 master-log.index drwx------ 2 mysql mysql 49 Dec 3 14:48 mydb drwx------ 2 mysql mysql 4096 Dec 3 14:48 mysql srwxrwxrwx 1 mysql mysql 0 Dec 4 14:14 mysql.sock drwx------ 2 mysql mysql 4096 Dec 3 14:44 performance_schema drwx------ 2 mysql mysql 19 Dec 3 14:44 test drwx------ 2 mysql mysql 79 Dec 3 14:48 testdb drwx------ 2 mysql mysql 36864 Dec 3 14:48 ultrax drwx------ 2 mysql mysql 8192 Dec 3 14:48 zabbix #================================================================================================== MariaDB [(none)]> SHOW MASTER STATUS; # 查看主节点二进制日志的记录文件及Position +-------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +-------------------+----------+--------------+------------------+ | master-log.000001 | 245 | | | +-------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
3.编辑从节点服务器的配置文件/etc/my.cnf,并启动服务，如下：
[root@slave ~]# vim /etc/my.cnf [mysqld] skip-name-resolve = ON innodb-file-per-table = ON relay-log=relay-log # 中继日志 server-id=2 # server-id=2 #=================================================================================================== [root@slave ~]# systemctl start mariadb.service # 启动服务 [root@slave ~]# ss -tnl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 50 *:3306 *:* LISTEN 0 128 *:22 *:* LISTEN 0 128 127.0.0.1:631 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 127.0.0.1:6010 *:* LISTEN 0 128 127.0.0.1:6011 *:* #=================================================================================================== [root@slave ~]# ll /var/lib/mysql/ # 查看其数据库目录这时还没有发现中继日志relay-log，只有当复制数据后才会有 total 36904 -rw-rw---- 1 mysql mysql 16384 Nov 17 15:50 aria_log.00000001 -rw-rw---- 1 mysql mysql 52 Nov 17 15:50 aria_log_control -rw-rw---- 1 mysql mysql 27262976 Dec 3 15:14 ibdata1 -rw-rw---- 1 mysql mysql 5242880 Dec 3 15:14 ib_logfile0 -rw-rw---- 1 mysql mysql 5242880 Nov 17 15:23 ib_logfile1 drwx------ 2 mysql mysql 19 Oct 30 20:23 mydb drwx------ 2 mysql mysql 4096 Oct 30 20:02 mysql srwxrwxrwx 1 mysql mysql 0 Dec 3 15:14 mysql.sock drwx------ 2 mysql mysql 4096 Oct 30 20:02 performance_schema drwx------ 2 mysql mysql 6 Oct 30 20:02 test drwx------ 2 mysql mysql 8192 Nov 17 00:35 zabbix_proxy
4.在主服务器上授权一个可以连接复制的用户账号，如下：
MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'repluser'@'10.1.%.%' IDENTIFIED BY 'replpass'; Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> FLUSH PRIVILEGES; Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> SHOW MASTER STATUS; +-------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +-------------------+----------+--------------+------------------+ | master-log.000001 | 494 | | | +-------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
5.在从服务器上设置连接主服务器的相关信息，并启动复制
MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='10.1.252.153', -> MASTER_USER='repluser', -> MASTER_PASSWORD='replpass', -> MASTER_LOG_FILE='master-log.000001', # 复制主节点的二进制的日志文件 -> MASTER_LOG_POS=245; # 复制主节点二进制日志开始的位置 Query OK, 0 rows affected (0.07 sec) MariaDB [(none)]> SHOW SLAVE STATUS\G # 查看slave从节点的信息，发现还没有启动 *************************** 1. row *************************** Slave_IO_State: Master_Host: 10.1.252.153 # 连接的主节点主机 Master_User: repluser # 用户 Master_Port: 3306 # 端口 Connect_Retry: 60 # 重试时间默认为60s Master_Log_File: master-log.000001 # 复制的二进制日志文件 Read_Master_Log_Pos: 245 # 复制的二进制日志文件起始位置 Relay_Log_File: relay-log.000001 # 中继日志的日志文件 Relay_Log_Pos: 4 # 中继日志的起始位置 Relay_Master_Log_File: master-log.000001 Slave_IO_Running: No # 从主节点读取数据到中继日志中 Slave_SQL_Running: No # 从中继日志中读取事件，然后同步到本地数据库中； 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: 245 # 现在所处的复制位置 Relay_Log_Space: 245 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: NULL # 落后于主服务器多少秒 Master_SSL_Verify_Server_Cert: No # 是否基于ssl进行复制 Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 0 # 主节点的ID号 1 row in set (0.00 sec) #========================================================================================= MariaDB [(none)]> START SLAVE; # 启动复制线程 Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> SHOW SLAVE STATUS\G # 再次查看slave状态 *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 10.1.252.153 Master_User: repluser Master_Port: 3306 Connect_Retry: 60 Master_Log_File: master-log.000001 Read_Master_Log_Pos: 245 Relay_Log_File: relay-log.000002 Relay_Log_Pos: 530 Relay_Master_Log_File: master-log.000001 Slave_IO_Running: Yes # 已经启动从主节点复制数据到中继日志中 Slave_SQL_Running: Yes # 启动线程从本地中继日志中同步数据到磁盘 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: 245 Relay_Log_Space: 818 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: 1 1 row in set (0.00 sec)
6.测试，在主节点创建一个数据库并查看二进制日志的位置，然后在从节点上查看其状态是否有延迟；
# 在主节点创建数据库，查看二进制的位置 MariaDB [mysql]> SHOW MASTER STATUS; +-------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +-------------------+----------+--------------+------------------+ | master-log.000001 | 494 | | | +-------------------+----------+--------------+------------------+ 1 row in set (0.00 sec) MariaDB [mysql]> CREATE DATABASE taotao; Query OK, 1 row affected (0.01 sec) MariaDB [mysql]> SHOW MASTER STATUS; +-------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +-------------------+----------+--------------+------------------+ | master-log.000001 | 584 | | | +-------------------+----------+--------------+------------------+ 1 row in set (0.00 sec) #======================================================================================== # 在从节点查看slave状态，看是否落后于主节点 MariaDB [(none)]> SHOW SLAVE STATUS\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 10.1.252.153 Master_User: repluser Master_Port: 3306 Connect_Retry: 60 Master_Log_File: master-log.000001 Read_Master_Log_Pos: 332 Relay_Log_File: relay-log.000002 Relay_Log_Pos: 617 Relay_Master_Log_File: master-log.000001 Slave_IO_Running: Yes Slave_SQL_Running: 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: 584 # 现在复制所处的位置和主节点相同 Relay_Log_Space: 905 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 # 没有落后主节点 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: 1 1 row in set (0.00 sec) MariaDB [(none)]> SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | mydb | | mysql | | performance_schema | | taotao | # 创建的taotao数据库 | test | | zabbix_proxy | +--------------------+ 7 rows in set (0.00 sec)
7.从服务器我们要求其只能读不能写，所以要设置其全局变量参数为只读，如下：
MariaDB [(none)]> SELECT @@global.read_only; +--------------------+ | @@global.read_only | +--------------------+ | 0 | +--------------------+ 1 row in set (0.00 sec) MariaDB [(none)]> SET @@global.read_only=1; Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> SELECT @@global.read_only; +--------------------+ | @@global.read_only | +--------------------+ | 1 | +--------------------+ 1 row in set (0.00 sec)
如上，就是主从复制的整个过程...
2.主主复制配置步骤及操作演示
★互为主从：两个节点各自都要开启 binlog 和 relay log；
1.数据不一致；
2.自动增长id；
☉定义一个节点使用奇数id
auto_increment_offset=1
auto_increment_increment=2
☉另一个节点使用偶数id
auto_increment_offset=2
auto_increment_increment=2
★配置：
1.server_id必须要使用不同值；
2.均启用binlog和relay log；
3.存在自动增长id的表，为了使得id不相冲突，需要定义其自动增长方式；
☉服务启动后执行如下两步：
4.都授权有复制权限的用户账号；
5.各把对方指定为主节点；
实验：主主复制
实验环境同主从复制
这里我把主从复制生成的数据库目录/var/lib/mysql全部删除了
操作步骤如下：
1.首先配置主节点1的配置文件/etc/my.cnf,如下：
[root@master1 ~]# vim /etc/my.cnf [mysqld] skip_name_resolve = ON innodb_file_per_table = ON log_bin=master-log relay-log=relay-log # 启动中继日志 server-id=1 auto_increment_offset=1 # 定义节点的id从基数开始 auto_increment_increment=2
2.配置主节点2的配置文件/etc/my.cnf，如下：
[root@master2 ~]# vim /etc/my.cnf [mysqld] skip-name-resolve = ON innodb-file-per-table = ON log-bin=master-log # 开启二进制日志 relay-log=relay-log server-id=2 auto_increment_offset=2 # 定义节点的id从偶数开始 auto_increment_increment=2
3.分别启动两个主节点master1和master2的服务，并授权一个可以连接复制的用户账号，如下：
1）主节点master1
[root@master1 ~]# systemctl start mariadb.service MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'repluser'@'10.1.%.%' IDENTIFIED BY 'replpass'; Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> FLUSH PRIVILEGES; Query OK, 0 rows affected (0.00 sec)
2）主节点master2
[root@master2 ~]# systemctl start mariadb.service MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'repluser'@'10.1.%.%' IDENTIFIED BY 'replpass'; Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> FLUSH PRIVILEGES; Query OK, 0 rows affected (0.00 sec)
4.查看两个主节点各自是否有二进制日志，以及二进制日志的起始位置
1）master1
[root@master1 ~]# ls /var/lib/mysql/ aria_log.00000001 ibdata1 ib_logfile1 master-log.000002 master-log.index mysql.sock test aria_log_control ib_logfile0 master-log.000001 master-log.000003 mysql performance_schema MariaDB [(none)]> SHOW MASTER STATUS; +-------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +-------------------+----------+--------------+------------------+ | master-log.000003 | 504 | | | +-------------------+----------+--------------+------------------+ 1 row in set (0.01 sec)
2）master2
[root@master2 ~]# ls /var/lib/mysql/ aria_log.00000001 ibdata1 ib_logfile1 master-log.000002 master-log.index mysql.sock test aria_log_control ib_logfile0 master-log.000001 master-log.000003 mysql performance_schema MariaDB [(none)]> SHOW MASTER STATUS; +-------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +-------------------+----------+--------------+------------------+ | master-log.000003 | 504 | | | +-------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
5.在两个主节点上设置分别把对方指定为主节点
1）master1
# 设定指定master2为主节点，二进制日志的起始位置为504 MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='10.1.249.103', MASTER_USER='repluser', MASTER_PASSWORD='replpass', MASTER_LOG_FILE='master-log.000003', MASTER_LOG_POS=504; Query OK, 0 rows affected (0.09 sec) # 启动复制功能 MariaDB [(none)]> START SLAVE; Query OK, 0 rows affected (0.02 sec) # 查看Slave状态如下： MariaDB [(none)]> SHOW SLAVE STATUS\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 10.1.249.103 Master_User: repluser Master_Port: 3306 Connect_Retry: 60 Master_Log_File: master-log.000003 Read_Master_Log_Pos: 504 Relay_Log_File: relay-log.000002 Relay_Log_Pos: 530 Relay_Master_Log_File: master-log.000003 Slave_IO_Running: Yes Slave_SQL_Running: 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: 504 Relay_Log_Space: 818 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: 2 1 row in set (0.00 sec)
2）master2
# 设定指定master1为主节点，二进制日志的起始位置为504 MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='10.1.252.153', MASTER_USER='repluser', MASTER_PASSWORD='replpass', MASTER_LOG_FILE='master-log.000003', MASTER_LOG_POS=504; Query OK, 0 rows affected (0.03 sec) # 启动复制功能 MariaDB [(none)]> START SLAVE; Query OK, 0 rows affected (0.00 sec) # 查看状态如下： MariaDB [(none)]> SHOW SLAVE STATUS\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 10.1.252.153 Master_User: repluser Master_Port: 3306 Connect_Retry: 60 Master_Log_File: master-log.000003 Read_Master_Log_Pos: 504 Relay_Log_File: relay-log.000002 Relay_Log_Pos: 530 Relay_Master_Log_File: master-log.000003 Slave_IO_Running: Yes Slave_SQL_Running: 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: 504 Relay_Log_Space: 818 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: 1 1 row in set (0.00 sec)
6.测试，两节点能否互相复制；
1）在master1上创建数据库mydb
MariaDB [(none)]> CREATE DATABASE mydb; Query OK, 1 row affected (0.00 sec)
2）在master2上查看数据库mydb，并创建表tbl
MariaDB [(none)]> SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | mydb | | mysql | | performance_schema | | test | +--------------------+ 5 rows in set (0.00 sec) MariaDB [(none)]> USE mydb; Database changed MariaDB [mydb]> CREATE TABLE tbl1 (id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, name VARCHAR(30)); Query OK, 0 rows affected (0.07 sec)
3）在master1上查看创建的表tbl1
MariaDB [mydb]> SHOW TABLES; +----------------+ | Tables_in_mydb | +----------------+ | tbl1 | +----------------+ 1 row in set (0.00 sec) MariaDB [mydb]> DESC tbl1; +-------+------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+------------------+------+-----+---------+----------------+ | id | int(10) unsigned | NO | PRI | NULL | auto_increment | | name | varchar(30) | YES | | NULL | | +-------+------------------+------+-----+---------+----------------+ 2 rows in set (0.00 sec)
4）向表中插入单个数据和连续插入数据，查看序列号的排列情况
在master1上向tbl1插入数据stu1
MariaDB [mydb]> INSERT INTO tbl1 (name) VALUES ('stu1');
Query OK, 1 row affected (0.03 sec)
MariaDB [mydb]> SELECT * FROM tbl1;
+----+------+
| id | name |
+----+------+
| 1 | stu1 |
+----+------+
1 row in set (0.01 sec)
在master2上向tbl1插入数据stu2；
MariaDB [mydb]> INSERT INTO tbl1 (name) VALUES ('stu2');
Query OK, 1 row affected (0.00 sec)
MariaDB [mydb]> SELECT * FROM tbl1;
+----+------+
| id | name |
+----+------+
| 1 | stu1 |
| 2 | stu2 |
+----+------+
2 rows in set (0.00 sec)
在master1上向tbl1连续插入数据stu3，stu4，可以发现id不是按序向下排列的，是按奇数排列的，如下：
MariaDB [mydb]> INSERT INTO tbl1 (name) VALUES ('stu3'),('stu4');
Query OK, 2 rows affected (0.07 sec)
Records: 2 Duplicates: 0 Warnings: 0
MariaDB [mydb]> SELECT * FROM tbl1;
+----+------+
| id | name |
+----+------+
| 1 | stu1 |
| 2 | stu2 |
| 3 | stu3 |
| 5 | stu4 |
+----+------+
4 rows in set (0.01 sec)
在master2上向tbl1连续插入数据stu3，stu4，可以发现id不是按序向下排列的，是按偶数排列的，如下：
MariaDB [mydb]> INSERT INTO tbl1 (name) VALUES ('stu5'),('stu6');
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
MariaDB [mydb]> SELECT * FROM tbl1;
+----+------+
| id | name |
+----+------+
| 1 | stu1 |
| 2 | stu2 |
| 3 | stu3 |
| 5 | stu4 |
| 6 | stu5 |
| 8 | stu6 |
+----+------+
6 rows in set (0.00 sec)
如上，可以发现，向表中插入单个数据可以按顺序正常排列，但是如果连续插入数据的话，为了防止两个主节点冲突，所以按各自节点定义的序列号奇偶插入。
3.半同步复制
★支持多种插件：
/usr/lib64/mysql/plugins/
★需要安装插件方可使用：
mysql> INSTALL PLUGIN plugin_name SONAME 'shared_library_name';
★半同步复制：
semisync_master.so
semisync_slave.so
★主节点：
★从节点：
实验：半同步复制
实验环境：
半同步复制是基于主从复制模型的，所以实验环境是在主从复制的基础上配置的；
操作步骤如下：
1.配置主从复制的环境，如下：
1）主节点，编辑配置文件/etc/my.cnf
[root@master ~]# vim /etc/my.cnf [mysqld] skip_name_resolve = ON innodb_file_per_table = ON log_bin=master-log # 添加启动二进制日志文件 server-id=1 # server-id
2)从节点，编辑配置文件如下：
[root@slave ~]# vim /etc/my.cnf [mysqld] skip-name-resolve = ON innodb-file-per-table = ON relay-log=relay-log # 中继日志 server-id=2 # server-id=2
2.启动主节点服务器，授权一个可以连接复制的用户账号，并查看二进制日志文件的位置；
[root@master1 ~]# systemctl start mariadb.service MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'repluser'@'10.1.%.%' IDENTIFIED BY 'replpass'; Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> FLUSH PRIVILEGES; Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> SHOW MASTER STATUS; +-------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +-------------------+----------+--------------+------------------+ | master-log.000001 | 419 | | | +-------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
3.在从节点连接设置连接主节点服务器的相关信息，并启动复制功能；
MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='10.1.252.153', -> MASTER_USER='repluser', -> MASTER_PASSWORD='replpass', -> MASTER_LOG_FILE='master-log.000001', # 复制主节点的二进制的日志文件 -> MASTER_LOG_POS=419; # 复制主节点二进制日志开始的位置 Query OK, 0 rows affected (0.07 sec) MariaDB [(none)]> START SLAVE; # 启动复制线程 Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> SHOW SLAVE STATUS\G # 再次查看slave状态 *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 10.1.252.153 Master_User: repluser Master_Port: 3306 Connect_Retry: 60 Master_Log_File: master-log.000001 Read_Master_Log_Pos: 245 Relay_Log_File: relay-log.000002 Relay_Log_Pos: 530 Relay_Master_Log_File: master-log.000001 Slave_IO_Running: Yes # 已经启动从主节点复制数据到中继日志中 Slave_SQL_Running: Yes # 启动线程从本地中继日志中同步数据到磁盘 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: 245 Relay_Log_Space: 818 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: 1 1 row in set (0.00 sec)
如上，主从复制就已经配置好了，现在我们来实现半同步复制，因为我这里只有一主一从，所以，从节点和主节点之间为同步复制，如下：
4.在主节点上安装支持同步复制的插件 semisync_master.so，并启动该插件
MariaDB [(none)]> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so'; Query OK, 0 rows affected (0.16 sec) # 查看是否安装的插件 semisync_master.so 是否激活 MariaDB [(none)]> SHOW PLUGINS; +--------------------------------+----------+--------------------+--------------------+---------+ | Name | Status | Type | Library | License | +--------------------------------+----------+--------------------+--------------------+---------+ | binlog | ACTIVE | STORAGE ENGINE | NULL | GPL | | mysql_native_password | ACTIVE | AUTHENTICATION | NULL | GPL | | mysql_old_password | ACTIVE | AUTHENTICATION | NULL | GPL | | INNODB_BUFFER_PAGE_LRU | ACTIVE | INFORMATION SCHEMA | NULL | GPL | | INNODB_BUFFER_POOL_STATS | ACTIVE | INFORMATION SCHEMA | NULL | GPL | | FEDERATED | ACTIVE | STORAGE ENGINE | NULL | GPL | | BLACKHOLE | ACTIVE | STORAGE ENGINE | NULL | GPL | | Aria | ACTIVE | STORAGE ENGINE | NULL | GPL | | FEEDBACK | DISABLED | INFORMATION SCHEMA | NULL | GPL | | partition | ACTIVE | STORAGE ENGINE | NULL | GPL | | rpl_semi_sync_master | ACTIVE | REPLICATION | semisync_master.so | GPL | +--------------------------------+----------+--------------------+--------------------+---------+ 43 rows in set (0.01 sec) #======================================================================================== MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'rpl_semi%'; +------------------------------------+-------+ | Variable_name | Value | +------------------------------------+-------+ | rpl_semi_sync_master_enabled | OFF | # 现在为关闭状态 | rpl_semi_sync_master_timeout | 10000 | | rpl_semi_sync_master_trace_level | 32 | | rpl_semi_sync_master_wait_no_slave | ON | +------------------------------------+-------+ 4 rows in set (0.00 sec) MariaDB [(none)]> SET GLOBAL rpl_semi_sync_master_enabled=ON; # 启动插件 Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'rpl_semi%'; +------------------------------------+-------+ | Variable_name | Value | +------------------------------------+-------+ | rpl_semi_sync_master_enabled | ON | # 已经启动 | rpl_semi_sync_master_timeout | 10000 | # 超时时长，超过会降为异步复制 | rpl_semi_sync_master_trace_level | 32 | | rpl_semi_sync_master_wait_no_slave | ON | +------------------------------------+-------+ 4 rows in set (0.01 sec)
5.同样，在从节点上也安装支持异步复制的插件 semisync_slave.so，如下：
MariaDB [(none)]> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so'; Query OK, 0 rows affected (0.04 sec) # 确保安装的插件是激活的 MariaDB [(none)]> SHOW PLUGINS; +--------------------------------+----------+--------------------+-------------------+---------+ | Name | Status | Type | Library | License | +--------------------------------+----------+--------------------+-------------------+---------+ | binlog | ACTIVE | STORAGE ENGINE | NULL | GPL | | mysql_native_password | ACTIVE | AUTHENTICATION | NULL | GPL | | mysql_old_password | ACTIVE | AUTHENTICATION | NULL | GPL | | MRG_MYISAM | ACTIVE | STORAGE ENGINE | NULL | GPL | | MEMORY | ACTIVE | STORAGE ENGINE | NULL | GPL | |INNODB_BUFFER_POOL_STATS | ACTIVE | INFORMATION SCHEMA | NULL | GPL | | FEDERATED | ACTIVE | STORAGE ENGINE | NULL | GPL | | BLACKHOLE | ACTIVE | STORAGE ENGINE | NULL | GPL | | Aria | ACTIVE | STORAGE ENGINE | NULL | GPL | | FEEDBACK | DISABLED | INFORMATION SCHEMA | NULL | GPL | | partition | ACTIVE | STORAGE ENGINE | NULL | GPL | | rpl_semi_sync_slave | ACTIVE | REPLICATION | semisync_slave.so | GPL | +--------------------------------+----------+--------------------+-------------------+---------+ 43 rows in set (0.00 sec) #=================================================================================================== MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'rpl_semi%'; +---------------------------------+-------+ | Variable_name | Value | +---------------------------------+-------+ | rpl_semi_sync_slave_enabled | OFF | # 目前为关闭状态 | rpl_semi_sync_slave_trace_level | 32 | +---------------------------------+-------+ 2 rows in set (0.00 sec) MariaDB [(none)]> SET GLOBAL rpl_semi_sync_slave_enabled=ON; # 启动插件 Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'rpl_semi%'; +---------------------------------+-------+ | Variable_name | Value | +---------------------------------+-------+ | rpl_semi_sync_slave_enabled | ON | # 正常启动 | rpl_semi_sync_slave_trace_level | 32 | +---------------------------------+-------+ 2 rows in set (0.01 sec)
6.在从节点上首先关闭复制线程，然后再启动，在主节点上可以发现同步复制的从节点个数从0变为1；
# 在从节点上首先关闭IO复制线程，然后再启动，因为刚启动同步复制插件不会自动跳转为同步； MariaDB [(none)]> STOP SLAVE IO_THREAD; Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> START SLAVE IO_THREAD; Query OK, 0 rows affected (0.01 sec) #======================================================================================== # 在主节点上查看两次同步复制的状态 MariaDB [(none)]> SHOW GLOBAL STATUS LIKE '%semi%'; +--------------------------------------------+-------+ | Variable_name | Value | +--------------------------------------------+-------+ | Rpl_semi_sync_master_clients | 0 | # 同步复制的客户端个数为0 | Rpl_semi_sync_master_net_avg_wait_time | 0 | | Rpl_semi_sync_master_net_wait_time | 0 | | Rpl_semi_sync_master_net_waits | 0 | | Rpl_semi_sync_master_no_times | 0 | | Rpl_semi_sync_master_no_tx | 0 | | Rpl_semi_sync_master_status | ON | | Rpl_semi_sync_master_timefunc_failures | 0 | | Rpl_semi_sync_master_tx_avg_wait_time | 0 | | Rpl_semi_sync_master_tx_wait_time | 0 | | Rpl_semi_sync_master_tx_waits | 0 | | Rpl_semi_sync_master_wait_pos_backtraverse | 0 | | Rpl_semi_sync_master_wait_sessions | 0 | | Rpl_semi_sync_master_yes_tx | 0 | +--------------------------------------------+-------+ 14 rows in set (0.00 sec) MariaDB [(none)]> SHOW GLOBAL STATUS LIKE '%semi%'; +--------------------------------------------+-------+ | Variable_name | Value | +--------------------------------------------+-------+ | Rpl_semi_sync_master_clients | 1 | # 同步复制的客户端个数为1 | Rpl_semi_sync_master_net_avg_wait_time | 0 | # 等待的平均时间 | Rpl_semi_sync_master_net_wait_time | 0 | # 主节点等待次数的累计时间 | Rpl_semi_sync_master_net_waits | 0 | # 主节点等待的次数 | Rpl_semi_sync_master_no_times | 0 | | Rpl_semi_sync_master_no_tx | 0 | | Rpl_semi_sync_master_status | ON | # 主服务器节点是否启用 | Rpl_semi_sync_master_timefunc_failures | 0 | | Rpl_semi_sync_master_tx_avg_wait_time | 0 | | Rpl_semi_sync_master_tx_wait_time | 0 | | Rpl_semi_sync_master_tx_waits | 0 | | Rpl_semi_sync_master_wait_pos_backtraverse | 0 | | Rpl_semi_sync_master_wait_sessions | 0 | | Rpl_semi_sync_master_yes_tx | 0 | +--------------------------------------------+-------+ 14 rows in set (0.01 sec)
测试：
在主节点导入hellodb数据库，再次查看同步复制的状态，如下：
# 导入hellodb数据库 MariaDB [(none)]> \. /root/hellodb.sql # 查看同步复制的状态，可以发现 MariaDB [hellodb]> SHOW GLOBAL STATUS LIKE '%semi%'; +--------------------------------------------+-------+ | Variable_name | Value | +--------------------------------------------+-------+ | Rpl_semi_sync_master_clients | 1 | | Rpl_semi_sync_master_net_avg_wait_time | 1580 | # 平均等待时长1.58s | Rpl_semi_sync_master_net_wait_time | 55334 | # 累计等待时长55334ms | Rpl_semi_sync_master_net_waits | 35 | # 一共等待35次 | Rpl_semi_sync_master_no_times | 0 | | Rpl_semi_sync_master_no_tx | 0 | | Rpl_semi_sync_master_status | ON | | Rpl_semi_sync_master_timefunc_failures | 0 | | Rpl_semi_sync_master_tx_avg_wait_time | 1727 | | Rpl_semi_sync_master_tx_wait_time | 55287 | | Rpl_semi_sync_master_tx_waits | 32 | # 等待事务提交的次数 | Rpl_semi_sync_master_wait_pos_backtraverse | 0 | | Rpl_semi_sync_master_wait_sessions | 0 | | Rpl_semi_sync_master_yes_tx | 35 | +--------------------------------------------+-------+ 14 rows in set (0.00 sec)