MySQL结构介绍及多实例主从复制

一.mysql结构介绍

1.客户端与服务端模型

1.数据是一个典型的C/S结构的服务

mysql自带的客户端工具
	mysql
	mysqladmin
	mysqldump
	
mysql是一个二进制程序,后台守护进程
	单进程
	多线程

2.mysql的连接方式

#1.TCP/IP连接
#2.socket连接

	#tcp/ip连接
	mysql -uroot -p -h127.0.0.1
	mysql -uroot -p -h127.0.0.1 -S /tmp/mysql.sock
	
	#socket连接
	mysql -uroot -p -hlocalhost
	mysql -uroot -p
	
	#注意:
	1)不一定-h就是TCP/IP连接,如果是localhosts就是socket连接
	2)socket连接比TCP/IP连接快,TCP/IP连接需要经过三次握手,四次挥手,慢
	3)socket连接只能本地连接,远程不能使用

2.实例

#1.什么是单实例?
	一个进程 + 多个线程 + 一个预分配的内存空间
#2.什么是多实例?
	多个进程 + 多个线程 + 多个预分配的内存空间

3.mysql程序结构

1)连接层

1.验证用户身份,判断用户名和密码
2.提供两种连接方式
3.与SQL层建立交互的线程

2)sql层

1.接收连接层传过来的数据
2.判断sql语句的语法
3.判断SQL语句的语义
4.解析器:解析sql语句,生成执行计划
5.优化器:选出执行计划中最优的计划
6.执行器:执行计划
	6.1 与存储引擎层建立交互
	6.2 将优化后要执行的SQL发给存储引擎层
7.记录缓存,如果前端有redis,将数据缓存至redis
8.记录日志

3)存储引擎层

1.与sql层建立交互,接收SQL层传来的SQL语句
2.与磁盘进行交互,获取数据,将数据返回给sql层

4.mysql逻辑结构

1.库:库的下面全是表
2.表:元数据 + 真实数据行
3.元数据:列 + 其它属性(行数+占用空间大小+权限)
4.列:列名字 + 数据类型 + 其他约束(非空、唯一、主键、非负数、自增长、默认值)

5.mysql物理结构

1.MySQL的最底层的物理结构是数据文件,也就是说,存储引擎层,打交道的文件,是数据文件。
2.存储引擎分为很多种类(Linux中的FS)
3.不同存储引擎的区别:存储方式、安全性、性能

#数据库创建时,不论库名还是表名,尽量都用小写字母

6.mysql物理大小

1.段:理论上一个表就是一个段,由多个区构成,(分区表是一个分区一个段)
2.区:连续的多个页构成
3.页:最小的数据存储单元,默认是16k

4.分区表:一个区构成一张段,就是一张表

二.mysql多实例

#mysql 多实例,也是多个配置文件启动数据库

mysql多个配置文件:
1.多个端口
2.多个socket文件
3.多个日志文件
4.多个srver_id
5.多个数据目录

1.创建多实例目录

[root@db03 local]# mkdir /usr/local/{3307,3308,3309}

2.编辑配置文件

[root@db03 local]# vim /usr/local/3307/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /usr/local/3307/data
port=3307
socket=/usr/local/3307/mysql.sock
server_id=1
log_err=/usr/local/3307/data/mysql.err
log_bin=/usr/local/3307/data/mysql-bin
skip-name-resolve

[root@db03 local]# vim /usr/local/3308/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /usr/local/3308/data
port=3308
socket=/usr/local/3308/mysql.sock
server_id=2
log_err=/usr/local/3308/data/mysql.err
log_bin=/usr/local/3308/data/mysql-bin
skip-name-resolve

[root@db03 local]# vim /usr/local/3309/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /usr/local/3309/data
port=3309
socket=/usr/local/3309/mysql.sock
server_id=3
log_err=/usr/local/3309/data/mysql.err
log_bin=/usr/local/3309/data/mysql-bin
skip-name-resolve

3.初始化多实例数据目录

[root@db03 local]# cd /usr/local/mysql/scripts/

#3307
[root@db03 scripts]# ./mysql_install_db --defaults-file=/usr/local/3307/my.cnf --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/3307/data

#3308
[root@db03 scripts]# ./mysql_install_db --defaults-file=/usr/local/3308/my.cnf --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/3308/data

#3309
[root@db03 scripts]# ./mysql_install_db --defaults-file=/usr/local/3309/my.cnf --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/3309/data

4.授权目录

[root@db03 scripts]# cd /usr/local/

[root@db03 local]# chown -R mysql.mysql /usr/local/330*

5.启动多实例

#关闭mysql(3306)
[root@db03 scripts]# systemctl stop mysqld
[root@db03 local]# cd /usr/local/mysql/scripts/

#开启
[root@db03 scripts]# mysqld_safe --defaults-file=/usr/local/3307/my.cnf &
[root@db03 scripts]# mysqld_safe --defaults-file=/usr/local/3308/my.cnf &
[root@db03 scripts]# mysqld_safe --defaults-file=/usr/local/3309/my.cnf &

#查看是否启动(有的机器能启三个,有的可能有四个,所以关闭3306的mysql)
[root@db03 scripts]# netstat -lntp
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      1/systemd           
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      6680/sshd           
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      6763/master         
tcp6       0      0 :::3307                 :::*                    LISTEN      8628/mysqld         
tcp6       0      0 :::3308                 :::*                    LISTEN      8920/mysqld         
tcp6       0      0 :::3309                 :::*                    LISTEN      9283/mysqld         
tcp6       0      0 :::111                  :::*                    LISTEN      1/systemd           
tcp6       0      0 :::22                   :::*                    LISTEN      6680/sshd           
tcp6       0      0 ::1:25                  :::*                    LISTEN      6763/master         

6.连接多实例并验证

[root@db03 scripts]# mysql -S /usr/local/3307/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 1     |
+---------------+-------+
[root@db03 scripts]# mysql -S /usr/local/3308/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 2     |
+---------------+-------+
[root@db03 scripts]# mysql -S /usr/local/3309/mysql.sock -e "show variables like ‘server_id‘"
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 3     |
+---------------+-------+

7.mysql多实例设置密码

[root@db03 scripts]# mysqladmin -S /usr/local/3307/mysql.sock -uroot password ‘123‘
Warning: Using a password on the command line interface can be insecure.
[root@db03 scripts]# mysqladmin -S /usr/local/3308/mysql.sock -uroot password ‘123‘
Warning: Using a password on the command line interface can be insecure.
[root@db03 scripts]# mysqladmin -S /usr/local/3309/mysql.sock -uroot password ‘123‘
Warning: Using a password on the command line interface can be insecure.

8.设置密码后连接

[root@db03 scripts]# mysql -S /usr/local/3307/mysql.sock -uroot -p
Enter password:
#可以登陆

#1.弄一个简单的连接方式
[root@db03 scripts]# vim /usr/bin/mysql3307
mysql -S /usr/local/3307/mysql.sock -uroot -p

[root@db03 scripts]# vim /usr/bin/mysql3308
mysql -S /usr/local/3308/mysql.sock -uroot -p

[root@db03 scripts]# vim /usr/bin/mysql3309
mysql -S /usr/local/3309/mysql.sock -uroot -p

#2.授权
[root@db03 scripts]# chmod +x /usr/bin/mysql33*

#3.试试能不能用
[root@db03 scripts]# mysql3307
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.6.46-log MySQL Community Server (GPL)

Copyright (c) 2000, 2019, 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> 
#

三.数据库多实例实现主从复制

1.主库操作

1.开启binlog(前面已经写好)

[root@db03 scripts]# vim /usr/local/3307/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /usr/local/3307/data
port=3307
socket=/usr/local/3307/mysql.sock
server_id=1
log_err=/usr/local/3307/data/mysql.err
log_bin=/usr/local/3307/data/mysql-bin
skip-name-resolve

2.主库授权一个用户,给从库用来连接

mysql> grant replication slave on *.* to rep@‘172.16.1.%‘ identified by ‘123‘;
Query OK, 0 rows affected (0.18 sec)

3.主库查看binlog信息

mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000003 |      468 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.03 sec)

2.从库的操作

#从库需要知道的主库信息
主库的IP
连接主库用的用户和密码
binlog信息

1.登陆数据库,配置主从

#3308和3309都要执行操作
mysql> change master to
    -> master_host=‘172.16.1.53‘,
    -> master_user=‘rep‘,
    -> master_password=‘123‘,
    -> master_log_file=‘mysql-bin.000003‘,
    -> master_log_pos=468,
    -> master_port=3307;
Query OK, 0 rows affected, 2 warnings (0.03 sec)

2.开启主从复制

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

3.查看主从是否成功

#3308,3309都执行,IO,SQL都是yes就说明成功
mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 172.16.1.53
                  Master_User: rep
                  Master_Port: 3307
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000003
          Read_Master_Log_Pos: 468
               Relay_Log_File: db03-relay-bin.000002
                Relay_Log_Pos: 283
        Relay_Master_Log_File: mysql-bin.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: 468
              Relay_Log_Space: 455
              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: a5c9a5c5-c2b0-11ea-9dbb-000c29354aad
             Master_Info_File: /usr/local/3308/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
           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
1 row in set (0.00 sec)

4.IO线程不为YES

1.测试网络
[root@db03 ~]# ping 172.16.1.53

2.测试端口
[root@db03 ~]# telnet 172.16.1.53 3307

3.测试主库授权的用户登录
[root@db03 ~]# mysql -urep -p123 -h172.16.1.53 -P3307

4.跳过反向解析设置
[root@db03 service]# vim /service/3307/my.cnf 
skip-name-resolve

5.UUID相同
[root@db03 ~]# cat /service/3307/data/auto.cnf 
[auto]
server-uuid=527f6221-c286-11ea-9ca7-000c29e19d84

5.SQL线程不为YES

1.主库有数据,从库没有
2.从库有数据,主库没有
#主从数据库数据不一致

#解决方法:把主库的数据全部导出来,放到从库里去,保证主从库数据一致,再做一次主从复制

MySQL结构介绍及多实例主从复制

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