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

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

4.主库db的更新事件(update、insert、delete)被写到binlog5.主库创建一个binlog dump thread，把binlog的内容发送到从库6.从库启动并发起连接，连接到主库7.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 log8.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/

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