MySQL 数据库的启动与关闭

MySQL数据库服务器通常指的的是mysqld，而命令行mysql则是mysql客户端程序，这两个概念通常容易混淆。通常启动mysql服务器即是启

MySQL数据库服务器通常指的的是mysqld，而命令行mysql则是mysql客户端程序，这两个概念通常容易混淆。通常启动mysql服务器即是启动mysqld进程，mysqld启动后，可以通过mysql连接到mysql服务器。本文主要描述了mysql服务器的几种启动方式以及如何关闭mysql服务器。

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Ubuntu 14.04下安装MySQL

《MySQL权威指南(原书第2版)》清晰中文扫描版 PDF

Ubuntu 14.04 LTS 安装 LNMP Nginx\PHP5 (PHP-FPM)\MySQL

Ubuntu 14.04下搭建MySQL主从服务器

Ubuntu 12.04 LTS 构建高可用分布式 MySQL 集群

Ubuntu 12.04下源代码安装MySQL5.6以及Python-MySQLdb

MySQL-5.5.38通用二进制安装

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1、直接使用mysqld启动
  mysqld 即是mysql服务器，可以调用该命令直接启动mysql服务器
  mysqld 从配置文件中读取[mysqld]以及[server]选项组的内容，，也可以通过直接在命令行跟随参数。
  mysqld服务器读取配置文件的顺序，对于有多个配置文件存在，且同一参数有多个值的情形，以最后一次读取为准。
  命令行跟随参数具有最高优先级

  #当前mysql服务器运行环境
  [root@rhel64a ~]# cat /etc/issue
  Red Hat Enterprise Linux Server release 6.4 (Santiago)
 
  #查看mysqld启动时的缺省选项
  [root@rhel64a ~]# mysqld --print-defaults
  mysqld would have been started with the following arguments:
  --socket=/tmp/mysql3306.sock --port=3306 --pid-file=/var/lib/mysql/my3306.pid --user=mysql --server-id=3306 --federated
  [root@rhel64a ~]# ps -ef|grep mysql
  root      2963  2840  0 14:10 pts/0    00:00:00 grep mysql
 
  # Author : Leshami
  # Blog  : 
 
  #查看mysqld启动配置文件的优先级
  [root@rhel64a ~]# mysqld --verbose --help |grep -A 1 "Default options"
  Default options are read from the following files in the given order:
  /etc/my.cnf /etc/mysql/my.cnf /usr/etc/my.cnf ~/.my.cnf
 
  #查看当前的my.cnf配置文件
  [root@rhel64a ~]# grep -v ^# /etc/my.cnf|head -n 7
  [mysqld]
  socket = /tmp/mysql3306.sock
  port = 3306
  pid-file = /var/lib/mysql/my3306.pid
  user = mysql
  server-id=3306
  federated
 
  #清空当前mysql服务器的错误日志文件
  [root@rhel64a ~]# cat /dev/null>/var/lib/mysql/rhel64a.ycdata.net.err
  [root@rhel64a ~]# mysqld &          #启动mysqld服务器
  [1] 3480
  [root@rhel64a ~]# 2014-10-25 14:20:42 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated.
  Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
  2014-10-25 14:20:42 3480 [Note] InnoDB: Using atomics to ref count buffer pool pages
  2014-10-25 14:20:42 3480 [Note] InnoDB: The InnoDB memory heap is disabled
  2014-10-25 14:20:42 3480 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
  2014-10-25 14:20:42 3480 [Note] InnoDB: Memory barrier is not used
  2014-10-25 14:20:42 3480 [Note] InnoDB: Compressed tables use zlib 1.2.3
  2014-10-25 14:20:42 3480 [Note] InnoDB: Using Linux native AIO
  2014-10-25 14:20:42 3480 [Note] InnoDB: Using CPU crc32 instructions
  2014-10-25 14:20:42 3480 [Note] InnoDB: Initializing buffer pool, size = 128.0M
  2014-10-25 14:20:42 3480 [Note] InnoDB: Completed initialization of buffer pool
  2014-10-25 14:20:42 3480 [Note] InnoDB: Highest supported file format is Barracuda.
  2014-10-25 14:20:42 3480 [Note] InnoDB: 128 rollback segment(s) are active.
  2014-10-25 14:20:42 3480 [Note] InnoDB: Waiting for purge to start
  2014-10-25 14:20:42 3480 [Note] InnoDB: 5.6.21 started; log sequence number 1626087
  2014-10-25 14:20:42 3480 [Note] Server hostname (bind-address): '*'; port: 3306
  2014-10-25 14:20:42 3480 [Note] IPv6 is available.
  2014-10-25 14:20:42 3480 [Note]  - '::' resolves to '::';
  2014-10-25 14:20:42 3480 [Note] Server socket created on IP: '::'.
  2014-10-25 14:20:42 3480 [Note] Event Scheduler: Loaded 0 events
  2014-10-25 14:20:42 3480 [Note] mysqld: ready for connections.
  Version: '5.6.21'  socket: '/tmp/mysql3306.sock'  port: 3306  MySQL Community Server (GPL)l
 
  #下面可以查询到mysqld进程
  [root@rhel64a ~]# ps -ef|grep mysql|grep -v grep
  mysql    18240  2641  1 20:25 pts/2    00:00:00 mysqld
  [root@rhel64a ~]# mysql -uroot -pxxx -P3306 --protocol=tcp
  root@localhost[(none)]> show variables like 'version';
  +---------------+--------+
  | Variable_name | Value  |
  +---------------+--------+
  | version      | 5.6.21 |
  +---------------+--------+

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