MySQL主从之多源复制（3主1从）搭建及同步测试

1. 一、MySQL主从复制简介
   1. 1.1、MySQL主从复制简介
   2. 1.2、主从复制的好处
   3. 1.3、MySQL主从复制流程
   4. 1.4、主从拓扑结构
2. 二、3主1从多源复制搭建
   1. 2.1、MySQL环境初始化
   2. 2.2、主库配置
   3. 2.3、从库配置
   4. 2.4、查询多源复制
   5. 2.5、测试多源复制
   6. 2.6、注意的点

一、MySQL主从复制简介

1.1、MySQL主从复制简介

MySQL主从复制（MySQL Replication）是指从一个MySQL主服务器(master)将数据拷贝到另一台或多台MySQL从服务器(slaves)的过程。将主数据库的DDL和DML操作通过二进制日志（binlog）传到从服务器（slave）上，然后在从服务器上对这些日志重新执行，从而使得主从服务器的数据保持同步。
MySQL从3.23版本开始提供复制的功能。

MySQL的Replication是一个多MySQL数据库做主从同步的方案，广泛用在各种对MySQL有更高性能、更高可靠性要求的场合。

1.2、主从复制的好处

主从复制有以下几方面的好处：

1. 数据备份(Data Backup)
   只是简单的对数据库进行备份，降低数据丢失的风险，
2. 线下统计
   用于报表等对数据时效性要求不高的场合。
3. 负载均衡(Load Balance)、读写分离
   主要用在MySQL集群，解决单点故障或做故障切换；以降低单台服务器的负载和风险，如实现读写分离，可以使得服务器访问负荷比较均衡。
4. 数据分发(Data DistributIOn)、灾备
   主要用于多数据中心或异地备份，实现数据分发与同步。
5. 高可用和数据容错(High Availability and Failover)
   MySQL自带的健康监控和检测，根据配置的时间间隔，可以检测主库是否正常工作，一旦发现主库宕机或无法正常工作，就会选择到最好的一个备库上。

1.3、MySQL主从复制流程

1.4、主从拓扑结构

二、3主1从多源复制搭建

2.1、MySQL环境初始化

-- 搭建3主1从-- 配置网络环境docker pull mysql:5.7.30docker network create --subnet=172.72.0.0/24 mysql-network-- 创建参数目录mkdir -p /lhrmysqltest2/master1/conf.dmkdir -p /lhrmysqltest2/master2/conf.dmkdir -p /lhrmysqltest2/master3/conf.dmkdir -p /lhrmysqltest2/slave/conf.d-- 删除之前的docker rm -f mysql5730M33265 mysql5730M33266 mysql5730M33267 mysql5730S33268-- 申请主库1docker run -d --name mysql5730M33265 \   -h master1 -p 33265:3306 --net=mysql-network --ip 172.72.0.10 \   -v /lhrmysqltest2/master1/conf.d:/etc/mysql/conf.d \   -e MYSQL_ROOT_PASSWORD=lhr \   mysql:5.7.30-- 申请主库2docker run -d --name mysql5730M33266 \   -h master2 -p 33266:3306 --net=mysql-network --ip 172.72.0.11 \   -v /lhrmysqltest2/master2/conf.d:/etc/mysql/conf.d \   -e MYSQL_ROOT_PASSWORD=lhr \   mysql:5.7.30-- 申请主库3docker run -d --name mysql5730M33267 \   -h master3 -p 33267:3306 --net=mysql-network --ip 172.72.0.12 \   -v /lhrmysqltest2/master3/conf.d:/etc/mysql/conf.d \   -e MYSQL_ROOT_PASSWORD=lhr \   mysql:5.7.30-- 申请从库docker run -d --name mysql5730S33268 \   -h slave1 -p 33268:3306 --net=mysql-network --ip 172.72.0.13 \   -v /lhrmysqltest2/slave/conf.d:/etc/mysql/conf.d \   -e MYSQL_ROOT_PASSWORD=lhr \   mysql:5.7.30-- 配置主库1的参数cat > /lhrmysqltest2/master1/conf.d/my.cnf << "EOF"[mysqld]port=3306character_set_server=utf8mb4secure_file_priv=server-id = 573033265log-bin =binlog_format=rowexpire_logs_days = 30max_binlog_size  = 100Mbinlog-ignore-db = mysqlbinlog-ignore-db = information_schemabinlog-ignore-db = performance_schemabinlog-ignore-db = sysreplicate_ignore_db=information_schemareplicate_ignore_db=performance_schemareplicate_ignore_db=mysqlreplicate_ignore_db=sysgtid-mode=ONenforce-gtid-consistency=onskip_name_resolvereport_host=172.72.0.10EOF-- 配置主库2的参数cat > /lhrmysqltest2/master2/conf.d/my.cnf << "EOF"[mysqld]port=3306character_set_server=utf8mb4secure_file_priv=server-id = 573033266log-bin = binlog_format=rowexpire_logs_days = 30max_binlog_size  = 100Mbinlog-ignore-db = mysqlbinlog-ignore-db = information_schemabinlog-ignore-db = performance_schemabinlog-ignore-db = sysreplicate_ignore_db=information_schemareplicate_ignore_db=performance_schemareplicate_ignore_db=mysqlreplicate_ignore_db=sysgtid-mode=ONenforce-gtid-consistency=ONskip_name_resolvereport_host=172.72.0.11EOF-- 配置主库3的参数cat > /lhrmysqltest2/master3/conf.d/my.cnf << "EOF"[mysqld]port=3306character_set_server=utf8mb4secure_file_priv=server-id = 573033267log-bin = binlog_format=rowexpire_logs_days = 30max_binlog_size  = 100Mbinlog-ignore-db = mysqlbinlog-ignore-db = information_schemabinlog-ignore-db = performance_schemabinlog-ignore-db = sysreplicate_ignore_db=information_schemareplicate_ignore_db=performance_schemareplicate_ignore_db=mysqlreplicate_ignore_db=sysgtid-mode=ONenforce-gtid-consistency=ONskip_name_resolvereport_host=172.72.0.12EOF-- 配置从库的参数cat > /lhrmysqltest2/slave/conf.d/my.cnf << "EOF"[mysqld]port=3306character_set_server=utf8mb4secure_file_priv=server-id = 573033268log-bin = binlog_format=rowexpire_logs_days = 30max_binlog_size  = 100Mbinlog-ignore-db = mysqlbinlog-ignore-db = information_schemabinlog-ignore-db = performance_schemabinlog-ignore-db = sysreplicate_ignore_db=information_schemareplicate_ignore_db=performance_schemareplicate_ignore_db=mysqlreplicate_ignore_db=sysgtid-mode=ONenforce-gtid-consistency=ONskip_name_resolvereport_host=172.72.0.13master-info-repository = tablerelay-log-info-repository = tableEOF-- 重启主机docker restart mysql5730M33265docker restart mysql5730M33266docker restart mysql5730M33267docker restart mysql5730S33268docker psdocker exec -it mysql5730M33265 bashdocker exec -it mysql5730M33265 mysql -uroot -plhrmysql -uroot -plhr -h192.168.66.35 -P33265 -e "select @@hostname,@@server_id,@@server_uuid"mysql -uroot -plhr -h192.168.66.35 -P33266 -e "select @@hostname,@@server_id,@@server_uuid"mysql -uroot -plhr -h192.168.66.35 -P33267 -e "select @@hostname,@@server_id,@@server_uuid"mysql -uroot -plhr -h192.168.66.35 -P33268 -e "select @@hostname,@@server_id,@@server_uuid"

2.2、主库配置

-- 在3台主库分别创建复制用户mysql -uroot -plhr -h192.168.66.35 -P33265mysql -uroot -plhr -h192.168.66.35 -P33266mysql -uroot -plhr -h192.168.66.35 -P33267grant replication slave on *.* to repl@'%' identified by 'lhr';select user,host,grant_priv,password_last_changed,authentication_string from mysql.user; show master status \G;show slave hosts;select @@hostname,@@server_id,@@server_uuid;

2.3、从库配置

-- 从库做以下配置mysql -uroot -plhr -h192.168.66.35 -P33268-- 配置主库1到从库的复制路径change master to master_host='172.72.0.10',master_port=3306,master_user='repl',master_password='lhr',master_auto_position=1  FOR CHANNEL 'Master1';-- 配置主库2到从库的复制路径change master to master_host='172.72.0.11',master_port=3306,master_user='repl',master_password='lhr',master_auto_position=1  FOR CHANNEL 'Master2';-- 配置主库3到从库的复制路径change master to master_host='172.72.0.12',master_port=3306,master_user='repl',master_password='lhr',master_auto_position=1  FOR CHANNEL 'Master3';-- 启动所有SLAVEmysql> START SLAVE;-- 也可以单独启动需要同步的通道mysql> START SLAVE FOR CHANNEL 'master1';mysql> START SLAVE FOR CHANNEL 'master2';mysql> START SLAVE FOR CHANNEL 'master3';

2.4、查询多源复制

-- 在从库查询show slave status \G;-- 如果要查看单一信道的复制的详细状态，可以使用以下命令：mysql> SHOW SLAVE STATUS FOR CHANNEL 'master1'\G;-- 通过表查询select a.master_log_pos,a.host,a.user_name,a.user_password,a.port,a.uuid,a.channel_name from  mysql.slave_master_info a;select * from mysql.slave_relay_log_info;select * from mysql.slave_worker_info;select * from mysql.gtid_executed;-- 在 performance_schema 库中，提供了复制相关的一些视图，可供查看复制相关的信息。select * from performance_schema.replication_applier_configuration;select * from performance_schema.replication_applier_status;select * from performance_schema.replication_applier_status_by_coordinator;select * from performance_schema.replication_applier_status_by_worker;select * from performance_schema.replication_connection_configuration;select * from performance_schema.replication_connection_status;select * from performance_schema.replication_group_member_stats;select * from performance_schema.replication_group_members;-- 合并SQLselect rcc.CHANNEL_NAME,rcc.`HOST`,rcc.`PORT`,rcc.`USER`,rcc.CONNECTION_RETRY_COUNT,rcc.CONNECTION_RETRY_INTERVAL,rcs.SOURCE_UUID,rcs.THREAD_ID,rcs.SERVICE_STATE,rcs.COUNT_RECEIVED_HEARTBEATS,rcs.LAST_HEARTBEAT_TIMESTAMP,rcs.LAST_ERROR_NUMBER,rcs.LAST_ERROR_MESSAGE,rcs.LAST_ERROR_TIMESTAMPfrom performance_schema.replication_connection_configuration rcc,      performance_schema.replication_connection_status rcswhere rcc.CHANNEL_NAME=rcs.CHANNEL_NAME;-- 线程查询SELECT *FROM performance_schema.threads aWHERE a.`NAME` IN ( 'thread/sql/slave_IO', 'thread/sql/slave_sql' ) or a.PROCESSLIST_COMMAND in ('Binlog Dump','Binlog Dump GTID') ;SELECT * FROM  information_schema.`PROCESSLIST` a where a.USER='system user' or a.command  in ('Binlog Dump','Binlog Dump GTID') ;MySQL [(none)]> SELECT *    -> FROM performance_schema.threads a    -> WHERE a.`NAME` IN ( 'thread/sql/slave_IO', 'thread/sql/slave_sql' ) or a.PROCESSLIST_COMMAND in ('Binlog Dump','Binlog Dump GTID') ;+-----------+----------------------+------------+----------------+------------------+------------------+----------------+---------------------+------------------+--------------------------------------------------------+------------------+------------------+------+--------------+---------+-----------------+--------------+| THREAD_ID | NAME                 | TYPE       | PROCESSLIST_ID | PROCESSLIST_USER | PROCESSLIST_HOST | PROCESSLIST_DB | PROCESSLIST_COMMAND | PROCESSLIST_TIME | PROCESSLIST_STATE                                      | PROCESSLIST_INFO | PARENT_THREAD_ID | ROLE | INSTRUMENTED | HISTORY | CONNECTION_TYPE | THREAD_OS_ID |+-----------+----------------------+------------+----------------+------------------+------------------+----------------+---------------------+------------------+--------------------------------------------------------+------------------+------------------+------+--------------+---------+-----------------+--------------+|        29 | thread/sql/slave_io  | FOREGROUND |              4 | root             | 172.72.0.1       | NULL           | Connect             |              252 | Waiting for master to send event                       | NULL             |               28 | NULL | YES          | YES     | NULL            |           75 ||        30 | thread/sql/slave_sql | FOREGROUND |              5 | root             | 172.72.0.1       | NULL           | Connect             |              325 | Slave has read all relay log; waiting for more updates | NULL             |               28 | NULL | YES          | YES     | NULL            |           76 ||        31 | thread/sql/slave_io  | FOREGROUND |              6 | root             | 172.72.0.1       | NULL           | Connect             |              252 | Waiting for master to send event                       | NULL             |               28 | NULL | YES          | YES     | NULL            |           77 ||        32 | thread/sql/slave_sql | FOREGROUND |              7 | root             | 172.72.0.1       | NULL           | Connect             |              322 | Slave has read all relay log; waiting for more updates | NULL             |               28 | NULL | YES          | YES     | NULL            |           78 ||        33 | thread/sql/slave_io  | FOREGROUND |              8 | root             | 172.72.0.1       | NULL           | Connect             |              252 | Waiting for master to send event                       | NULL             |               28 | NULL | YES          | YES     | NULL            |           79 ||        34 | thread/sql/slave_sql | FOREGROUND |              9 | root             | 172.72.0.1       | NULL           | Connect             |              320 | Slave has read all relay log; waiting for more updates | NULL             |               28 | NULL | YES          | YES     | NULL            |           80 |+-----------+----------------------+------------+----------------+------------------+------------------+----------------+---------------------+------------------+--------------------------------------------------------+------------------+------------------+------+--------------+---------+-----------------+--------------+6 rows in set (0.09 sec)

2.5、测试多源复制

-- 测试多源-- mysql -uroot -plhr -h192.168.66.35 -P33265create database master1;use master1;CREATE TABLE `test1` (`id` int(11) DEFAULT NULL,`count` int(11) DEFAULT NULL);insert into test1 values(1,1);-- mysql -uroot -plhr -h192.168.66.35 -P33266create database master2;use master2;CREATE TABLE `test2` (`id` int(11) DEFAULT NULL,`count` int(11) DEFAULT NULL);insert into test2 values(2,2);-- mysql -uroot -plhr -h192.168.66.35 -P33267create database master3;use master3;CREATE TABLE `test3` (`id` int(11) DEFAULT NULL,`count` int(11) DEFAULT NULL);insert into test3 values(3,3);-- 从库查询-- mysql -uroot -plhr -h192.168.66.35 -P33268show databases;SELECT * FROM master1.test1;SELECT * FROM master2.test2;SELECT * FROM master3.test3;

从库查询：

MySQL [(none)]> show databases;+--------------------+| Database           |+--------------------+| information_schema || master1            || master2            || master3            || mysql              || performance_schema || sys                |+--------------------+7 rows in set (0.05 sec)MySQL [(none)]> SELECT * FROM master1.test1;+------+-------+| id   | count |+------+-------+|    1 |     1 |+------+-------+1 row in set (0.06 sec)MySQL [(none)]> SELECT * FROM master2.test2;+------+-------+| id   | count |+------+-------+|    2 |     2 |+------+-------+1 row in set (0.05 sec)MySQL [(none)]> SELECT * FROM master3.test3;+------+-------+| id   | count |+------+-------+|    3 |     3 |+------+-------+1 row in set (0.05 sec)MySQL [(none)]>

2.6、注意的点

1、初次配置耗时较长，需要将各个master的数据dump下来，再source到slave上。

2、需要考虑各master数据增长频率，slave的数据增长频率是这些数据的总和。如果太高，会导致大量的磁盘IO，造成数据更新延迟，最严重的是会影响正常的查询。

3、如果多个主数据库实例中存在同名的库，则同名库的表都会放到一个库中；

4、如果同名库中的表名相同且结构相同，则数据会合并到一起；如果结构不同，则先建的有效。