MySQL主从同步

WeMeHM

已于 2022-11-15 22:30:14 修改

阅读量551

点赞数

文章标签： mysql 数据库

于 2022-11-15 22:29:46 首次发布

本文链接：https://blog.youkuaiyun.com/m0_58154448/article/details/127875285

版权

原理：

1. 在master机器上的操作：

当master的数据发生变化时，此事件的变化会按照顺序写入==bin-log==中。当slave连接到master时，master机器会为slave开启==bin-log dump==线程。当master的bin-log发生变化时，bin-log dump线程会通知slave，并将相应的binlog内容发送给slave。

2. 在slave机器上的操作：

当主从同步开启的时候，slave会创建两个线程：==**I/O线程**==。该线程连接到master机器，master机器上的bin-log dump线程会将bin-log的内容发送给该I/O线程。该I/O线程接收到bin-log内容后，再将内容写入到本地的==relay log==；==**sql线程**==，该线程读取到I/O线程写入的relay log，并且根据relay log的内容对slave数据库做相应的操作。

3. 从库生成两个线程，一个I/O线程，一个SQL线程；

I/O线程去请求主库的binlog，并将得到的binlog日志写到relay log（中继日志）文件中；

主库会生成一个 log dump 线程，用来给从库I/O线程传binlog；

SQL 线程会读取relay log文件中的日志，并解析成具体操作，来实现主从的操作一致，而最终使得数据一致；

搭建过程：

attention：搭建MySQL主从同步前，需要分别在主库和从库上安装并配置好MySQL数据库！！！

环境： IP：192.168.10.21 主机名：server1 版本：MySQL5.7 角色：Master

IP：192.168.10.22 主机名：server2 版本：MySQL5.7 角色：Slave

配置master：192.168.10.21

配置/etc/my.cnf

[root@server1 ~]# vim /etc/my.cnf
2 [client]
3 port=3306
4 socket=/data/mysql/mysql.sock
5
6 [mysqld]
7 character‐set‐server=utf8
8 collation‐server=utf8_general_ci
9
10 skip‐name‐resolve
11 user=mysql
12 port=3306
13 basedir=/usr/local/mysql57
14 datadir=/data/mysql
15 tmpdir=/tmp
16 socket=/data/mysql/mysql.sock
17
18 log‐error=/data/mysql/mysqld.log
19 pid‐file=/data/mysql/mysqld.pid
20
21 log‐bin=mysql‐bin‐master #启用二进制日志
22 server‐id=1 #本机数据库ID 标示
23 binlog‐do‐db=testdb #可以被从服务器复制的库, 二进制需要同步的数据库名
24 binlog‐ignore‐db=mysql #不可以被从服务器复制的库
25 lower_case_table_names=1
26 #注意：Linux下部署安装MySQL，默认不忽略表名大小写，需要手动到/etc/my.cnf 下配置 lower_case_table_names=1 使Linux环境下MySQL忽略表名大小写，否则使用MyCAT的时候会提示找不到表的错误！

[root@server1 ~]# service mysqld restart
Shutting down MySQL. SUCCESS!
Starting MySQL. SUCCESS!

创建要同步的数据库并创建表

[root@server1 ~]# mysql -uroot -p111
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.19-log Source distribution

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 database testdb;
Query OK, 1 row affected (0.00 sec)

mysql> use testdb;
Database changed
mysql> CREATE TABLE TABLE666 (bTypeID int,bName char(16),price int,publishing char(16));
Query OK, 0 rows affected (0.00 sec)

授权

mysql> grant replication slave on *.* to slave@"192.168.10.%" identified by "111";

Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> show binlog events\G
*************************** 1. row ***************************
Log_name: mysql-bin-master.000001
Pos: 4
Event_type: Format_desc
Server_id: 1
End_log_pos: 123
Info: Server ver: 5.7.19-log, Binlog ver: 4
*************************** 2. row ***************************
Log_name: mysql-bin-master.000001
Pos: 123
Event_type: Previous_gtids
Server_id: 1
End_log_pos: 154
Info:
*************************** 3. row ***************************
Log_name: mysql-bin-master.000001
Pos: 154
Event_type: Anonymous_Gtid
Server_id: 1
End_log_pos: 219
Info: SET @@SESSION.GTID_NEXT= 'ANONYMOUS'
*************************** 4. row ***************************
Log_name: mysql-bin-master.000001
Pos: 219
Event_type: Query
Server_id: 1
End_log_pos: 398
Info: ALTER USER 'root'@'localhost' IDENTIFIED WITH 'mysql_native_password' AS '*832EB84CB764129D05D498ED9CA7E5CE9B8F83EB'
*************************** 5. row ***************************
Log_name: mysql-bin-master.000001
Pos: 398
Event_type: Anonymous_Gtid
Server_id: 1
End_log_pos: 463
Info: SET @@SESSION.GTID_NEXT= 'ANONYMOUS'
*************************** 6. row ***************************
Log_name: mysql-bin-master.000001
Pos: 463
Event_type: Query
Server_id: 1
End_log_pos: 550
Info: flush privileges
*************************** 7. row ***************************
Log_name: mysql-bin-master.000001
Pos: 550
Event_type: Stop
Server_id: 1
End_log_pos: 573
Info:
7 rows in set (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> exit
Bye
[root@server1 ~]# ls /data/mysql
auto.cnf ib_logfile1 mysql-bin-master.000002 mysql.sock testdb
ib_buffer_pool ibtmp1 mysql-bin-master.index mysql.sock.lock
ibdata1 mysql mysqld.log performance_schema
ib_logfile0 mysql-bin-master.000001 mysqld.pid sys

如果不知道这个文件在哪可以cat /etc/my.cnf查看"datadir=什么"

导出数据库并传给从服务器

[root@server1 ~]# cd /usr/local/src/mysql-5.7.19
[root@server1 mysql-5.7.19]# mysqldump -uroot -p111 -B testdb > testdb.sql
mysqldump: [Warning] Using a password on the command line interface can be insecure.
[root@server1 mysql-5.7.19]# ls
BUILD CPackConfig.cmake libbinlogevents mysys_ssl strings
client CPackSourceConfig.cmake libbinlogstandalone packaging support-files
cmake CTestTestfile.cmake libevent plugin testclients
CMakeCache.txt dbug libmysql rapid testdb.sql
CMakeFiles Docs libmysqld README unittest
cmake_install.cmake Doxyfile-perfschema libservices regex VERSION
CMakeLists.txt extra make_dist.cmake scripts VERSION.dep
cmd-line-utils include Makefile source_downloads vio
config.h.cmake info_macros.cmake man sql win
configure.cmake INSTALL mysql-test sql-common zlib
COPYING install_manifest.txt mysys storage
[root@server1 mysql-5.7.19]# scp testdb.sql 192.168.10.22:/root
The authenticity of host '192.168.10.22 (192.168.10.22)' can't be established.
ECDSA key fingerprint is 02:58:f1:1a:ea:0a:59:21:af:83:2a:2c:8e:3a:d5:fe.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.10.22' (ECDSA) to the list of known hosts.
root@192.168.10.22's password: (输入另外一台机的密码)
testdb.sql 100% 2027 2.0KB/s 00:00

配置Slave 192.168.10.22

配置/etc/my.cnf

1 [root@server2 ~]# vim /etc/my.cnf
2 [client]
3 port=3306
4 socket=/data/mysql/mysql.sock
5
6 [mysqld]
7 ctestdbracter‐set‐server=utf8
8 collation‐server=utf8_general_ci
9
10 skip‐name‐resolve
11 user=mysql
12 port=3306
13 basedir=/usr/local/mysql57
14 datadir=/data/mysql
15 tmpdir=/tmp
16 socket=/data/mysql/mysql.sock
17
18 log‐error=/data/mysql/mysqld.log
19 pid‐file=/data/mysql/mysqld.pid
20
21 server‐id=2
22 #从服务器ID号，不要和主ID相同，如果设置多个从服务器，每个从服务器必须有一个唯一的server‐id值，必须与主服务器的以及其它从服务器的不相同。可以认为server‐id值类似于IP地址：这些ID值能唯一识别复制服务器群集中的每个服务器实例。
23 lower_case_table_names=1
24 #注意：Linux下部署安装MySQL，默认不忽略表名大小写，需要手动到/etc/my.cnf 下配置 lower_case_table_names=1 使Linux环境下MySQL忽略表名大小写，否则使用MyCAT的时候会提示找不到表的错误！
[root@server2 ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL. SUCCESS!

两台数据库服务器MySQL的版本要一致
[root@server1 ~]# mysql -uroot -p111
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.19-log Source distribution

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.

[root@server2 ~]# mysql -uroot -p111
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 5.7.19 Source distribution

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.

测试连接到主数据库是否成功

[root@server2 ~]# cd /data/mysql/
[root@server2 mysql]# mysql -uslave -p111 -h 192.168.10.21
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.7.19-log Source distribution

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 |
+--------------------+
1 row in set (0.00 sec)
#这个时候看不到testdb数据库是正常的

向testdb数据库导入数据

[root@server2 mysql]# cd
[root@server2 ~]# mysql -uroot -p111 < testdb.sql
mysql: [Warning] Using a password on the command line interface can be insecure.
[root@server2 ~]# mysql -uroot -p111
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 5.7.19 Source distribution

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 testdb;
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> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| table666 |
+------------------+
1 row in set (0.00 sec)

mysql> exit
Bye

指定主数据库，然后重启slave这台机器

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> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> change master to master_host='192.168.10.21',master_user='slave',master_password='111';
Query OK, 0 rows affected, 2 warnings (0.01 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.10.21
Master_User: slave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin-master.000002
Read_Master_Log_Pos: 1153
Relay_Log_File: server2-relay-bin.000003
Relay_Log_Pos: 381
Relay_Master_Log_File: mysql-bin-master.000002
Slave_IO_Running: Yes
Slave_SQL_Running: No
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 1007
Last_Error: Error 'Can't create database 'testdb'; database exists' on query. Default database: 'testdb'. Query: 'create database testdb'
Skip_Counter: 0
Exec_Master_Log_Pos: 154
Relay_Log_Space: 2212
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
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 1007
Last_SQL_Error: Error 'Can't create database 'testdb'; database exists' on query. Default database: 'testdb'. Query: 'create database testdb'
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID: cf7b706e-64ca-11ed-a114-000c293661ae
Master_Info_File: /data/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State:
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp: 221115 20:05:58
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)

#有可能出现以上错误，解决方法如下：

mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)

mysql> set global sql_slave_skip_counter=1;
Query OK, 0 rows affected (0.00 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.10.21
Master_User: slave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin-master.000002
Read_Master_Log_Pos: 1153
Relay_Log_File: server2-relay-bin.000005
Relay_Log_Pos: 327
Relay_Master_Log_File: mysql-bin-master.000002
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: 1153
Relay_Log_Space: 709
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
Master_UUID: cf7b706e-64ca-11ed-a114-000c293661ae
Master_Info_File: /data/mysql/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:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)

Slave_IO_Running: Yes 负责与主机的I/O通信
Slave_SQL_Running: Yes 负责自己的slave mysql进程
两个均为yes就成功了！！！

再到主数据库上查看状态

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 processlist\G
*************************** 1. row ***************************
Id: 7
User: root
Host: localhost
db: NULL
Command: Query
Time: 0
State: starting
Info: show processlist
*************************** 2. row ***************************
Id: 11
User: slave
Host: 192.168.10.22:50506
db: NULL
Command: Binlog Dump
Time: 207
State: Master has sent all binlog to slave; waiting for more updates
Info: NULL
2 rows in set (0.00 sec)

测试主从同步

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 testdb;
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> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| table666 |
+------------------+
1 row in set (0.00 sec)

mysql> select * from table666;
Empty set (0.00 sec)

mysql> INSERT INTO table666(bTypeId,bName,price,publishing) VALUES('1','Linux1','70','WM');
Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO table666(bTypeId,bName,price,publishing) VALUES('2','Linux2','71','WM');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO table666(bTypeId,bName,price,publishing) VALUES('3','Linux3','72','WM');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO table666(bTypeId,bName,price,publishing) VALUES('4','MySQL1','73','QH');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO table666(bTypeId,bName,price,publishing) VALUES('5','MySQL2','74','QH');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO table666(bTypeId,bName,price,publishing) VALUES('6','MySQL3','78','QH');
Query OK, 1 row affected (0.01 sec)

mysql> select * from table666;
+---------+--------+-------+------------+
| bTypeID | bName | price | publishing |
+---------+--------+-------+------------+
| 1 | Linux1 | 70 | WM |
| 2 | Linux2 | 71 | WM |
| 3 | Linux3 | 72 | WM |
| 4 | MySQL1 | 73 | QH |
| 5 | MySQL2 | 74 | QH |
| 6 | MySQL3 | 78 | QH |
+---------+--------+-------+------------+
6 rows in set (0.00 sec)

mysql> exit
Bye

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> select * from testdb.table666;
+---------+--------+-------+------------+
| bTypeID | bName | price | publishing |
+---------+--------+-------+------------+
| 1 | Linux1 | 70 | WM |
| 2 | Linux2 | 71 | WM |
| 3 | Linux3 | 72 | WM |
| 4 | MySQL1 | 73 | QH |
| 5 | MySQL2 | 74 | QH |
| 6 | MySQL3 | 78 | QH |
+---------+--------+-------+------------+
6 rows in set (0.01 sec)

主库

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> select * from table666;
ERROR 1046 (3D000): No database selected
mysql> use testdb
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 table666;
+---------+--------+-------+------------+
| bTypeID | bName | price | publishing |
+---------+--------+-------+------------+
| 1 | Linux1 | 70 | WM |
| 2 | Linux2 | 71 | WM |
| 3 | Linux3 | 72 | WM |
| 4 | MySQL1 | 73 | QH |
| 5 | MySQL2 | 74 | QH |
| 6 | MySQL3 | 78 | QH |
+---------+--------+-------+------------+
6 rows in set (0.00 sec)

mysql> delete from table666 where bName="MySQL3";
Query OK, 1 row affected (0.00 sec)

mysql> select * from table666;
+---------+--------+-------+------------+
| bTypeID | bName | price | publishing |
+---------+--------+-------+------------+
| 1 | Linux1 | 70 | WM |
| 2 | Linux2 | 71 | WM |
| 3 | Linux3 | 72 | WM |
| 4 | MySQL1 | 73 | QH |
| 5 | MySQL2 | 74 | QH |
+---------+--------+-------+------------+
5 rows in set (0.00 sec)

mysql>

从库

mysql> select * from testdb.table666;
+---------+--------+-------+------------+
| bTypeID | bName | price | publishing |
+---------+--------+-------+------------+
| 1 | Linux1 | 70 | WM |
| 2 | Linux2 | 71 | WM |
| 3 | Linux3 | 72 | WM |
| 4 | MySQL1 | 73 | QH |
| 5 | MySQL2 | 74 | QH |
+---------+--------+-------+------------+
5 rows in set (0.00 sec)

==至此，MySQL主从同步搭建成功！！！==