无法使用 mysqldump 导出数据库:未知变量 'datadir=/var/lib/mysql' [英] Cannot export database with mysqldump: unknown variable 'datadir=/var/lib/mysql'

问题描述

尝试导出数据库时:

mysqldump -u root -p --opt databasename > databasename.sql

它失败并显示:

mysqldump: unknown variable 'datadir=/var/lib/mysql'

<小时>

上网查了一下，发现mysql配置文件有:

---

I researched on internet and found cases where the mysql configuration file had:

[mysqldump]
datadir=/var/lib/mysql

在这些情况下，解决方案是删除 [mysqldump]/datadir 变量，但在我的情况下，我的任何配置文件中都没有该变量，因此该解决方案对我没有用.

In those cases the solution was to delete that [mysqldump]/datadir variable, but in my case I didn't have that variable in any of my configuration files, hence that solution wasn't useful for me.

为了查看所有可能的配置文件在我的系统中的位置，我使用了mysqld --verbose --help，结果显示:

To see where all the possible configuration files are located in my system, I used mysqld --verbose --help, and the result showed:

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

其中一些配置文件不存在，存在的甚至没有[mysqldump]变量组，例如我的/etc/my.cnf 有:

Some of these configuration files don't exist, and the ones that exist doesn't even have the [mysqldump] variable-group, for example my /etc/my.cnf has:

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
default-storage-engine=MyISAM
innodb_file_per_table=1
max_allowed_packet=268435456
local-infile=0
max_connections=1024
table_definition_cache=400
performance_schema=0
open_files_limit=10000

[client]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

那么原因和解决方法是什么?

Then what's the cause and solution?

推荐答案

[client]
datadir=/var/lib/mysql

删除 [client] 下的 datadir=/var/lib/mysql 行.客户端不需要知道 MySQL 服务器在哪里存储数据.

Remove the datadir=/var/lib/mysql line under [client]. The client doesn't need to know where the MySQL server is storing data.

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