phpMyAdmin端口配置和mysql主从复制

phpmMyAdmin

phpMyAdmin is a free software tool written in PHP, intended to handle the administration of MySQL over the Web. phpMyAdmin supports a wide range of operations on MySQL and MariaDB.
最重要的是免费的，若不是navicat在ubuntu下没有破解版，可能根本就不会关注它了，安装可参考:
https://www.cnblogs.com/xpwi/p/9821371.html

主界面

在这里插入图片描述

基本上可以和navicat匹配，不过支持的数据库类型较navicat就差好多了。不过目前mysql的使用还是比较多的，phpMyAdmin基本足够了。

端口修改

默认端口是80，不过整个端口通常都会别占用，因此需要修改端口号。具体过程如下:

1. gedit /etc/apache2/ports.conf

# If you just change the port or add more ports here, you will likely also
# have to change the VirtualHost statement in
# /etc/apache2/sites-enabled/000-default.conf
#  change port to 8081
Listen 8081

<IfModule ssl_module>
    Listen 443
</IfModule>

<IfModule mod_gnutls.c>
    Listen 443
</IfModule>

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

2. gedit /etc/apache2/sites-available/000-default.conf

<VirtualHost *:8081>
    # The ServerName directive sets the request scheme, hostname and port that
    # the server uses to identify itself. This is used when creating
    # redirection URLs. In the context of virtual hosts, the ServerName
    # specifies what hostname must appear in the request's Host: header to
    # match this virtual host. For the default virtual host (this file) this
    # value is not decisive as it is used as a last resort host regardless.
    # However, you must set it for any further virtual host explicitly.
    #ServerName www.example.com

    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/html

    # Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
    # error, crit, alert, emerg.
    # It is also possible to configure the loglevel for particular
    # modules, e.g.
    #LogLevel info ssl:warn

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined

    # For most configuration files from conf-available/, which are
    # enabled or disabled at a global level, it is possible to
    # include a line for only one particular virtual host. For example the
    # following line enables the CGI configuration for this host only
    # after it has been globally disabled with "a2disconf".
    #Include conf-available/serve-cgi-bin.conf
</VirtualHost>

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

mysql主从复制

使用场景

1. 在业务复杂的系统中，有这么一个情景，有一句sql语句需要锁表，导致暂时不能使用读的服务，那么就很影响运行中的业务，使用主从复制，让主库负责写，从库负责读，这样，即使主库出现了锁表的情景，通过读从库也可以保证业务的正常运行。
2. 做数据的热备，主库宕机后能够及时替换主库，保证业务可用性。
3. 架构的扩展。业务量越来越大，I/O访问频率过高，单机无法满足，此时做多库的存储，降低磁盘I/O访问的频率，提高单个机器的I/O性能。

MySQL主从复制的流程

在这里插入图片描述

1. 主库db的更新事件(update、insert、delete)被写到binlog
2. 主库创建一个binlog dump thread，把binlog的内容发送到从库
3. 从库启动并发起连接，连接到主库
4. 从库启动之后，创建一个I/O线程，读取主库传过来的binlog内容并写入到relay log
5. 从库启动之后，创建一个SQL线程，从relay log里面读取内容，从Exec_Master_Log_Pos位置开始执行读取到的更新事件，将更新内容写入到slave的db

参考

https://blog.csdn.net/zai_xia/article/details/90379016
https://www.phpmyadmin.net/

写在最后

后续会持续更新工作中常用到的工具和配置，关于phpMyAdmin和mysql的任何问题，都可以私信交流。

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