- 架构
mysql是cs架构，在服务端可以启动该mysqld服务，mysqld进程默认监听在tcp:3306。在客户端使用命令行工具mysql或者图形化工具navicat for mysql进行远程连接，连接信息包括user,password,host，连接池组件会到mysql.user表中验证用户和密码是否ok，登录host时候匹配。通过则登录成功。
在服务端，最外层是connector组件，用于外部应用程序访问数据。
下一层是连接池组件，用于验证等。管理服务和工具，SQL接口组件，
下面是插件式存储引擎，文件系统。
查看mysql在磁盘上的存储：
MariaDB [(none)]> show variables like 'datadir'; +---------------+-----------------+ | Variable_name | Value | +---------------+-----------------+ | datadir | /var/lib/mysql/ | +---------------+-----------------+ 1 row in set (0.00 sec)
[root@sqlm mysql]# ll -h total 47M -rw-rw---- 1 mysql mysql 16K Mar 3 10:03 aria_log.00000001 -rw-rw---- 1 mysql mysql 52 Mar 3 10:03 aria_log_control -rw-rw---- 1 mysql mysql 26M Mar 20 19:58 ibdata1 -rw-rw---- 1 mysql mysql 5.0M Mar 20 19:58 ib_logfile0 -rw-rw---- 1 mysql mysql 5.0M Mar 20 19:58 ib_logfile1 -rw-rw---- 1 mysql mysql 1.5K Feb 8 15:46 master1-bin.000001 -rw-rw---- 1 mysql mysql 1.8M Feb 11 14:35 master1-bin.000002 -rw-rw---- 1 mysql mysql 264 Mar 3 10:03 master1-bin.000003 -rw-rw---- 1 mysql mysql 8.8M Mar 6 17:09 master1-bin.000004 -rw-rw---- 1 mysql mysql 1.8K Mar 19 21:04 master1-bin.000005 -rw-rw---- 1 mysql mysql 245 Mar 20 19:41 master1-bin.000006 -rw-rw---- 1 mysql mysql 126 Mar 20 19:41 master1-bin.index
- 插件式存储引擎
存储引擎是mysql区别于其他数据库的一个最重要特性。存储引擎是表级别的，可以针对不同功能的表，设定不同的存储引擎（每个存储引擎的特点不一样），以达到最优性能。我们应该深刻的意识到，存储引擎是mysql的核心。
mysql提供了存储引擎接口，使我们可以编写自己的存储引擎。在大兴企业中，会有人员开发更加适合于自己业务的存储引擎。
show engines命令显示mysql支持的存储引擎。innodb为默认引擎。
MariaDB [(none)]> show engines; +--------------------+---------+----------------------------------------------------------------------------+--------------+------+------------+ | Engine | Support | Comment | Transactions | XA | Savepoints | +--------------------+---------+----------------------------------------------------------------------------+--------------+------+------------+ | CSV | YES | CSV storage engine | NO | NO | NO | | MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO | | MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO | | BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO | | MyISAM | YES | MyISAM storage engine | NO | NO | NO | | InnoDB | DEFAULT | Percona-XtraDB, Supports transactions, row-level locking, and foreign keys | YES | YES | YES | | ARCHIVE | YES | Archive storage engine | NO | NO | NO | | FEDERATED | YES | FederatedX pluggable storage engine | YES | NO | YES | | PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO | | Aria | YES | Crash-safe tables with MyISAM heritage | NO | NO | NO | +--------------------+---------+----------------------------------------------------------------------------+--------------+------+------------+ 10 rows in set (0.00 sec)
- 配置文件
mysql的配置文件以参数集的方式体现，每个参数集下有很多parameter=value的形式体现。[mysqld]为daemon service，[mysqld_safe]为线程安全。这些配置在3大点中有所体现。
[root@sqlm ~]# cat /etc/my.cnf [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock log-bin server_id=1 log-basename=master1 # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 # Settings user and group are ignored when systemd is used. # If you need to run mysqld under a different user or group, # customize your systemd unit file for mariadb according to the # instructions in http://fedoraproject.org/wiki/Systemd [mysqld_safe] log-error=/var/log/mariadb/mariadb.log pid-file=/var/run/mariadb/mariadb.pid # # include all files from the config directory # !includedir /etc/my.cnf.d log-bin=mysql-bin