如何找到 MySQL my.cnf 位置

Question

是否有一个 MySQL 命令来定位my.cnf配置文件，类似于 PHP 的phpinfo()定位它的php.ini ？

Answer 1

There is no internal MySQL command to trace this, it's a little too abstract. The file might be in 5 (or more?) locations, and they would all be valid because they load cascading.

• /etc/my.cnf
• /etc/mysql/my.cnf
• $MYSQL_HOME/my.cnf
• [datadir]/my.cnf
• ~/.my.cnf

Those are the default locations MySQL looks at. If it finds more than one, it will load each of them & values override each other (in the listed order, I think). Also, the --defaults-file parameter can override the whole thing, so... basically, it's a huge pain in the butt.

But thanks to it being so confusing, there's a good chance it's just in /etc/my.cnf.

(If you just want to see the values: SHOW VARIABLES , but you'll need the permissions to do so.)

Run mysql --help and you will see:

Default options are read from the following files in the given order: /etc/my.cnf /etc/mysql/my.cnf ~/.my.cnf

Answer 2

You can actually "request" MySQL for a list of all locations where it searches for my.cnf (or my.ini on Windows). It is not an SQL query though. Rather, execute:

$ mysqladmin --help

or, prior 5.7:

$ mysqld --help --verbose

In the very first lines you will find a message with a list of all my.cnf locations it looks for. On my machine it is:

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

Or, on Windows:

Default options are read from the following files in the given order:
C:\Windows\my.ini
C:\Windows\my.cnf
C:\my.ini
C:\my.cnf
C:\Program Files\MySQL\MySQL Server 5.5\my.ini
C:\Program Files\MySQL\MySQL Server 5.5\my.cnf

Note however, that it might be the case that there is no my.cnf file at any of these locations . So, you can create the file on your own - use one of the sample config files provided with MySQL distribution (on Linux - see /usr/share/mysql/*.cnf files and use whichever is appropriate for you - copy it to /etc/my.cnf and then modify as needed).

Also, note that there is also a command line option --defaults-file which may define custom path to my.cnf or my.ini file. For example, this is the case for MySQL 5.5 on Windows - it points to a my.ini file in the data directory, which is not normally listed with mysqld --help --verbose . On Windows - see service properties to find out if this is the case for you.

Finally, check the https://dev.mysql.com/doc/refman/8.0/en/option-files.html - it is described there in more details.

Answer 3

你总是可以在终端中运行 find 。

find / -name my.cnf

Answer 4

mysql --help | grep /my.cnf | xargs ls

will tell you where my.cnf is located on Mac/Linux

ls: cannot access '/etc/my.cnf': No such file or directory
ls: cannot access '~/.my.cnf': No such file or directory
 /etc/mysql/my.cnf

In this case, it is in /etc/mysql/my.cnf

ls: /etc/my.cnf: No such file or directory
ls: /etc/mysql/my.cnf: No such file or directory
ls: ~/.my.cnf: No such file or directory
/usr/local/etc/my.cnf

In this case, it is in /usr/local/etc/my.cnf

Answer 5

You can use :

locate my.cnf
whereis my.cnf
find . -name my.cnf

Answer 6

This might work:

strace mysql ";" 2>&1  | grep cnf

on my machine this outputs:

stat64("/etc/my.cnf", 0xbf9faafc)       = -1 ENOENT (No such file or directory)
stat64("/etc/mysql/my.cnf", {st_mode=S_IFREG|0644, st_size=4271, ...}) = 0
open("/etc/mysql/my.cnf", O_RDONLY|O_LARGEFILE) = 3
read(3, "# /etc/mysql/my.cnf: The global "..., 4096) = 4096
stat64("/home/xxxxx/.my.cnf", 0xbf9faafc) = -1 ENOENT (No such file or directory)

So it looks like /etc/mysql/my.cnf is the one since it stat64() and read() were successful.

Answer 7

By default, mysql search my.cnf first at /etc folder. If there is no /etc/my.cnf file inside this folder, I advise you to create new one in this folder as indicated by the documentation ( https://dev.mysql.com/doc/refman/5.6/en/option-files.html ).

You can also search for existing my.cnf furnished by your mysql installation. You can launch the following command

sudo find / -name "*.cnf"

You can use the following configuration file with myisam table and without innodb mysql support (from port installation of mysql on mac os x maverick). Please verify each command in this configuration file.

# Example MySQL config file for large systems.
#
# This is for a large system with memory = 512M where the system runs mainly
# MySQL.
#
# MySQL programs look for option files in a set of
# locations which depend on the deployment platform.
# You can copy this option file to one of those
# locations. For information about these locations, see:
# http://dev.mysql.com/doc/mysql/en/option-files.html
#
# In this file, you can use all long options that a program supports.
# If you want to know which options a program supports, run the program
# with the "--help" option.

# The following options will be passed to all MySQL clients
[client]
#password   = your_password
port        = 3306
socket      = /opt/local/var/run/mysql5/mysqld.sock

# Here follows entries for some specific programs

# The MySQL server
[mysqld]
port        = 3306
socket      = /opt/local/var/run/mysql5/mysqld.sock
skip-locking
key_buffer_size = 256M
max_allowed_packet = 1M
table_open_cache = 256
sort_buffer_size = 1M
read_buffer_size = 1M
read_rnd_buffer_size = 4M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_size= 16M
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 8

# Don't listen on a TCP/IP port at all. This can be a security enhancement,
# if all processes that need to connect to mysqld run on the same host.
# All interaction with mysqld must be made via Unix sockets or named pipes.
# Note that using this option without enabling named pipes on Windows
# (via the "enable-named-pipe" option) will render mysqld useless!
# 
#skip-networking

# Replication Master Server (default)
# binary logging is required for replication
log-bin=mysql-bin

# binary logging format - mixed recommended
binlog_format=mixed

# required unique id between 1 and 2^32 - 1
# defaults to 1 if master-host is not set
# but will not function as a master if omitted
server-id   = 1

# Replication Slave (comment out master section to use this)
#
# To configure this host as a replication slave, you can choose between
# two methods :
#
# 1) Use the CHANGE MASTER TO command (fully described in our manual) -
#    the syntax is:
#
#    CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=<port>,
#    MASTER_USER=<user>, MASTER_PASSWORD=<password> ;
#
#    where you replace <host>, <user>, <password> by quoted strings and
#    <port> by the master's port number (3306 by default).
#
#    Example:
#
#    CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,
#    MASTER_USER='joe', MASTER_PASSWORD='secret';
#
# OR
#
# 2) Set the variables below. However, in case you choose this method, then
#    start replication for the first time (even unsuccessfully, for example
#    if you mistyped the password in master-password and the slave fails to
#    connect), the slave will create a master.info file, and any later
#    change in this file to the variables' values below will be ignored and
#    overridden by the content of the master.info file, unless you shutdown
#    the slave server, delete master.info and restart the slaver server.
#    For that reason, you may want to leave the lines below untouched
#    (commented) and instead use CHANGE MASTER TO (see above)
#
# required unique id between 2 and 2^32 - 1
# (and different from the master)
# defaults to 2 if master-host is set
# but will not function as a slave if omitted
#server-id       = 2
#
# The replication master for this slave - required
#master-host     =   <hostname>
#
# The username the slave will use for authentication when connecting
# to the master - required
#master-user     =   <username>
#
# The password the slave will authenticate with when connecting to
# the master - required
#master-password =   <password>
#
# The port the master is listening on.
# optional - defaults to 3306
#master-port     =  <port>
#
# binary logging - not required for slaves, but recommended
#log-bin=mysql-bin

# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /opt/local/var/db/mysql5
#innodb_data_file_path = ibdata1:10M:autoextend
#innodb_log_group_home_dir = /opt/local/var/db/mysql5
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 256M
#innodb_additional_mem_pool_size = 20M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 64M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

[mysqldump]
quick
max_allowed_packet = 16M

[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates

[myisamchk]
key_buffer_size = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout

Answer 8

对于 Ubuntu 16：/etc/mysql/mysql.conf.d/mysqld.cnf

Answer 9

As noted by konyak you can get the list of places mysql will look for your my.cnf file by running mysqladmin --help . Since this is pretty verbose you can get to the part you care about quickly with:

$ mysqladmin --help | grep -A1 'Default options'

This will give you output similar to:

Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf /usr/local/etc/my.cnf ~/.my.cnf

Depending on how you installed mysql it is possible that none of these files are present yet. You can cat them in order to see how your config is being built and create your own my.cnf if needed at your preferred location.

Answer 10

I don't know how you've setup MySQL on your Linux environment but have you checked?

• /etc/my.cnf

Answer 11

Try running mysqld --help --verbose | grep my.cnf | tr " " "\n" mysqld --help --verbose | grep my.cnf | tr " " "\n"

Output will be something like

/etc/my.cnf
/etc/mysql/my.cnf
/usr/local/etc/my.cnf
~/.my.cnf

Answer 12

您也可以运行此命令。

mysql --help | grep cnf

Answer 13

If you're on a Mac with Homebrew, use

brew info mysql

You'll see something like

$ brew info mysql
mysql: stable 5.6.13 (bottled)
http://dev.mysql.com/doc/refman/5.6/en/
Conflicts with: mariadb, mysql-cluster, percona-server
/usr/local/Cellar/mysql/5.6.13 (9381 files, 354M) *

That last line is the INSTALLERDIR per the MySQL docs

Answer 14

Be aware that although mariadDB loads configuration details from the various my.cnf files as listed in the other answers here, it can also load them from other files with different names.

That means that if you make a change in one of the my.cnf files, it may get overwritten by another file of a different name. To make the change stick, you need to change it in the right (last loaded) config file - or, maybe, change it in all of them.

So how do you find all the config files that might be loaded? Instead of looking for my.cnf files, try running:

grep -r datadir /etc/mysql/

This will find all the places in which datadir is mentioned. In my case, it produces this answer:

/etc/mysql/mariadb.conf.d/50-server.cnf:datadir     = /var/lib/mysql 

When I edit that file (/etc/mysql/mariadb.conf.d/50-server.cnf) to change the value for datadir, it works, whereas changing it in my.cnf does not. So whatever option you are wanting to change, try looking for it this way.

Answer 15

发现我的使用

mysqld --help --verbose | grep my.cnf

Answer 16

Answered for only MySQL Workbench users,

Answer 17

所有很棒的建议，就我而言，我在这些位置都没有找到它，但是在/usr/share/mysql ，我有一个 RHEL 虚拟机并且我安装了mysql5.5

Answer 18

I installed xampp bundle with apache, php and mysql in ubuntu . There my.cnf file is located in /opt/lampp/etc/ folder. Hope it'll help somebody.

Answer 19

You will have to look through the various locations depending on your version of MySQL.

mysqld --help -verbose | grep my.cnf

For Homebrew:
/usr/local/Cellar/mysql/8.0.11/bin/mysqld (mysqld 8.0.11)

Default possible locations:
/etc/my.cnf
/etc/mysql/my.cnf
~/.my.cnf

Found mine here: 
/usr/local/etc/my.cnf

Answer 20

If you are on Debian/Ubuntu system and already equipped with modern versions of the database (everything from 5.7 up, also true for mysql 8) the best way to locate the actual .cnf file I have found is:

sudo update-alternatives --config my.cnf

You should see a output like this:

There are 3 choices for the alternative my.cnf (providing /etc/mysql/my.cnf).

  Selection    Path                        Priority   Status
------------------------------------------------------------
  0            /etc/mysql/mariadb.cnf       500       auto mode
  1            /etc/mysql/mariadb.cnf       500       manual mode
  2            /etc/mysql/my.cnf.fallback   100       manual mode
* 3            /etc/mysql/mysql.cnf         300       manual mode

There are two lines in /etc/mysql/mysql.cnf that it makes sense to pay attention to:

!includedir /etc/mysql/conf.d/
!includedir /etc/mysql/mysql.conf.d/

MySQL will go watching for all .cnf files in /etc/mysql/conf.d/ , then all files in /etc/mysql/mysql.conf.d/

Happy tuning!

Answer 21

Another option is to use the whereis command.

Eg whereis my.cnf

Answer 22

在 Ubuntu 上（直接编辑）：

$ sudo nano /etc/mysql.conf.d/mysqld.cnf

Answer 23

In case you are in a VPS and are trying to edit a my.cnf on an already running server you could try:

ps aux | grep mysql

You will be show the parameters the mysql command is being run and where the --defaults-file points to

Note that your server might be running more than one MySQL/MariaDB server's. If you see a line without --defaults-file parameter, that instance might be retrieving the configuration from the .cnf's that are mentioned on mysqladmin --help as others have pointed out.

Answer 24

You can find my.cnf or any other file with find command:

find / -name my.cnf (or any other file name)

1. find is a command
2. / (slash) is a path
3. my.cnf is a file name

Answer 25

If you are using MAMP, access Templates > MySQL (my.cnf) > [version]

If you are running MAMP windowless you may need to customize the toolbar using the Customize button.

Answer 26

对我来说，我有“ENGINE=MyISAM”类型的表，一旦我将它更改为“ENGINE=InnoDB”，它就可以在 Azure App Service 上的 PhpMyAdmin 中工作:)

Answer 27

It depend on your access right but for me this work on phpmyadmin sql console

SHOW VARIABLES;

then after to change some variables you can do

SET GLOBAL max_connections = 1000;

or

SET @@GLOBAL.max_connections = 1000;

give a try

Answer 28

MySQL 配置文件：

/etc/my.cnf

Answer 29

尝试

mysql --verbose --help | grep -A 1 "Default options"

Answer 30

For MariaDB 10.5 on Ubuntu 20.04.4 LTS (Focal Fossa) :

# The MariaDB configuration file
#
# The MariaDB/MySQL tools read configuration files in the following order:
# 0. "/etc/mysql/my.cnf" symlinks to this file, reason why all the rest is read.
# 1. "/etc/mysql/mariadb.cnf" (this file) to set global defaults,
# 2. "/etc/mysql/conf.d/*.cnf" to set global options.
# 3. "/etc/mysql/mariadb.conf.d/*.cnf" to set MariaDB-only options.
# 4. "~/.my.cnf" to set user-specific options.
#
# If the same option is defined multiple times, the last one will apply.