MySQL 安装+启动+报错的解决方案

目录

一、安装准备

1.1 下载

1.2 版本说明

二、安装步骤

2.1 解压缩

2.2 配置环境变量

2.3 配置文件

2.4 安装

2.5 启动/停止服务

三、使用说明

3.1 用户名密码登录

3.1 设置用户名密码

四、卸载步骤

4.1 卸载服务

五、安装问题

六、启动问题

6.1 提示【服务无法启动】

6.1.1 问题描述

6.1.2 解决方案

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一、安装准备

1.1 下载

       1、MySQL官网地址MySQLhttps://www.mysql.com/

        2、点击【DOWNLOAD】菜单。

        往下翻，点击【MySQL Community (GPL) Downloads】连接。

        选择【MySQL Community Server】选项，下载MySQL。

1.2 版本说明

        本文档编写时，使用的是8.0.26-win64的解压缩版本。

二、安装步骤

2.1 解压缩

        将压缩包解压缩到目标目录。

2.2 配置环境变量

        1、【我的电脑/此电脑】右键，点击【属性】，选择【高级系统配置】

        2、点击【环境变量】，在弹出框中，选择新建【系统变量】。

        变量名建议为：MYSQL_HOME；变量值为MySQL的解压路径；

        3、在【系统变量】中找到Path变量，并新增MYSQL的环境变量。

2.3 配置文件

        将如下内容拷贝到名为my.ini的文件中，并将其放入到解压根目录中。

        其中，较为重要的配置为：

        # 设置mysql客户端连接服务端时默认使用的端口；
        port=3306

        # 设置mysql的安装目录；
        basedir="D:\mysql\"

        # 设置mysql数据库的数据的存放目录；
        datadir="D:\mysql\data"

# MySQL Server Instance Configuration File
# ----------------------------------------------------------------------
# Generated by the MySQL Server Instance Configuration Wizard
#
#
# Installation Instructions
# ----------------------------------------------------------------------
#
#
# CLIENT SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by MySQL client applications.
# Note that only client applications shipped by MySQL are guaranteed
# to read this section. If you want your own MySQL client program to
# honor these values, you need to specify it as an option during the
# MySQL client library initialization.
#
[client]

# 设置mysql客户端连接服务端时默认使用的端口；
port=3306
# 绑定本地IP；
bind-address = 127.0.0.1
# 客户端默认字符集编码为utf8mb4；
default-character-set=utf8mb4

[mysql]

# MySQL默认字符集编码为utf8mb4；
default-character-set=utf8mb4

# SERVER SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by the MySQL Server. Make sure that
# you have installed the server correctly (see above) so it reads this
# file.
#
[mysqld]

# The TCP/IP Port the MySQL Server will listen on
# 设置默认端口为3306；
port=3306
# 绑定本地IP；
bind-address = 127.0.0.1

#Path to installation directory. All paths are usually resolved relative to this.
# 设置mysql的安装目录；
basedir="D:\mysql\"
#Path to the database root
# 设置mysql数据库的数据的存放目录；
datadir="D:\mysql\data"
[WinMySQLadmin]
# mysqld服务路径；
Server="D:\mysql\bin\mysqld.exe"

# The default character set that will be used when a new schema or table is
# created and no character set is defined
# 服务端默认字符集编码为utf8mb4；
default-character-set=utf8mb4

# The default storage engine that will be used when create new tables when
# 创建新表时将使用的默认存储引擎；
default-storage-engine=INNODB

# Set the SQL mode to strict
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"

# The maximum amount of concurrent sessions the MySQL server will
# allow. One of these connections will be reserved for a user with
# SUPER privileges to allow the administrator to login even if the
# connection limit has been reached.
# 允许最大连接数；
max_connections=100

# Query cache is used to cache SELECT results and later return them
# without actual executing the same query once again. Having the query
# cache enabled may result in significant speed improvements, if your
# have a lot of identical queries and rarely changing tables. See the
# "Qcache_lowmem_prunes" status variable to check if the current value
# is high enough for your load.
# Note: In case your tables change very often or if your queries are
# textually different every time, the query cache may result in a
# slowdown instead of a performance improvement.
# 查询缓存大小；
query_cache_size=0

# The number of open tables for all threads. Increasing this value
# increases the number of file descriptors that mysqld requires.
# Therefore you have to make sure to set the amount of open files
# allowed to at least 4096 in the variable "open-files-limit" in
# section 
[mysqld_safe]
# 表缓存大小；
table_cache=256

# Maximum size for internal (in-memory) temporary tables. If a table
# grows larger than this value, it is automatically converted to disk
# based table This limitation is for a single table. There can be many
# of them.
# 临时表大小；
tmp_table_size=26M

# How many threads we should keep in a cache for reuse. When a client
# disconnects, the client's threads are put in the cache if there aren't
# more than thread_cache_size threads from before.  This greatly reduces
# the amount of thread creations needed if you have a lot of new
# connections. (Normally this doesn't give a notable performance
# improvement if you have a good thread implementation.)
# 线程数；
thread_cache_size=8

#*** MyISAM Specific options

# The maximum size of the temporary file MySQL is allowed to use while
# recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
# If the file-size would be bigger than this, the index will be created
# through the key cache (which is slower).
myisam_max_sort_file_size=100G

# If the temporary file used for fast index creation would be bigger
# than using the key cache by the amount specified here, then prefer the
# key cache method.  This is mainly used to force long character keys in
# large tables to use the slower key cache method to create the index.
myisam_sort_buffer_size=52M

# Size of the Key Buffer, used to cache index blocks for MyISAM tables.
# Do not set it larger than 30% of your available memory, as some memory
# is also required by the OS to cache rows. Even if you're not using
# MyISAM tables, you should still set it to 8-64M as it will also be
# used for internal temporary disk tables.
key_buffer_size=40M

# Size of the buffer used for doing full table scans of MyISAM tables.
# Allocated per thread, if a full scan is needed.
read_buffer_size=64K
read_rnd_buffer_size=256K

# This buffer is allocated when MySQL needs to rebuild the index in
# REPAIR, OPTIMZE, ALTER table statements as well as in LOAD DATA INFILE
# into an empty table. It is allocated per thread so be careful with
# large settings.
sort_buffer_size=256K

#*** INNODB Specific options ***
# INNODB的数据存放目录；
innodb_data_home_dir="D:\mysql\data\INNODB\"

# Use this option if you have a MySQL server with InnoDB support enabled
# but you do not plan to use it. This will save memory and disk space
# and speed up some things.
#skip-innodb

# Additional memory pool that is used by InnoDB to store metadata
# information.  If InnoDB requires more memory for this purpose it will
# start to allocate it from the OS.  As this is fast enough on most
# recent operating systems, you normally do not need to change this
# value. SHOW INNODB STATUS will display the current amount used.
innodb_additional_mem_pool_size=2M

# If set to 1, InnoDB will flush (fsync) the transaction logs to the
# disk at each commit, which offers full ACID behavior. If you are
# willing to compromise this safety, and you are running small
# transactions, you may set this to 0 or 2 to reduce disk I/O to the
# logs. Value 0 means that the log is only written to the log file and
# the log file flushed to disk approximately once per second. Value 2
# means the log is written to the log file at each commit, but the log
# file is only flushed to disk approximately once per second.
innodb_flush_log_at_trx_commit=1

# The size of the buffer InnoDB uses for buffering log data. As soon as
# it is full, InnoDB will have to flush it to disk. As it is flushed
# once per second anyway, it does not make sense to have it very large
# (even with long transactions).
innodb_log_buffer_size=1M

# InnoDB, unlike MyISAM, uses a buffer pool to cache both indexes and
# row data. The bigger you set this the less disk I/O is needed to
# access data in tables. On a dedicated database server you may set this
# parameter up to 80% of the machine physical memory size. Do not set it
# too large, though, because competition of the physical memory may
# cause paging in the operating system.  Note that on 32bit systems you
# might be limited to 2-3.5G of user level memory per process, so do not
# set it too high.
innodb_buffer_pool_size=77M

# Size of each log file in a log group. You should set the combined size
# of log files to about 25%-100% of your buffer pool size to avoid
# unneeded buffer pool flush activity on log file overwrite. However,
# note that a larger logfile size will increase the time needed for the
# recovery process.
innodb_log_file_size=39M

# Number of threads allowed inside the InnoDB kernel. The optimal value
# depends highly on the application, hardware as well as the OS
# scheduler properties. A too high value may lead to thread thrashing.
innodb_thread_concurrency=8
 

2.4 安装

        1、使用管理员权限运行CMD（此处省略使用管理员运行CMD的方法）。

        2、使用盘符 + : 的形式，切换到目标盘符。

        3、使用CD切换到目标路径下。目标路径为解压缩目录\bin。

        4、运行mysqld install mysql --defaults-file="d:\mysql\my.ini"命令。

2.5 启动/停止服务

        运行net start mysql命令，服务启动成功。

        运行net stop mysql命令，服务停止成功。

三、使用说明

3.1 用户名密码登录

        服务初始化好后，会默认配置用户名和密码；

        A temporary password is generated for root@localhost: ******；

        输入mysql命令进行登录，-h代表IP地址，-u代表用户名，-p代表密码；

3.1 设置用户名密码

      登录后，执行命令：ALTER USER 'root'@'localhost' IDENTIFIED BY '新密码';，修改密码完成；

四、卸载步骤

4.1 卸载服务

        执行mysqld remove命令，卸载服务。

五、安装问题

暂无；

六、启动问题

6.1 提示【服务无法启动】

6.1.1 问题描述

       

        如图所示，提示服务无法启动。

6.1.2 解决方案

        根据2.3的配置，datadir="D:\mysql\data" 可知，在解压缩目录下的data目录中，存放有数据库相关文件。

        情况一：

        如果是手动创建了data目录，则进入目录后，可以看到后缀名为.err的文件，打开文件可以看到启动报错信息。

        报错说明初始化data目录失败。因此需要删除data目录，由mysql自己初始化data目录，此时重新尝试即可。

        情况二：

        如果使用mysqld install命令安装时，未初始化data目录，则说明安装“失败”了，启动时一定会报错。

        此时需要使用mysqld --initialize --console命令，初始化MySQL。

        初始化后，再执行mysqld install mysql --defaults-file="d:\mysql\my.ini"安装命令。

        此时，服务启动成功，可以正常使用。