How do I find the MySQL my.cnf location

问题:

Is there a MySQL command to locate the my.cnf configuration file, similar to how PHP\'s phpinfo() locates its php.ini?

回答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.)

回答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.

回答3:

You could always run find in a terminal.

find / -name my.cnf

回答4:

You can use :

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

回答5:

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.

回答6:

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

回答7:

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.

回答8:

Try running 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

回答9:

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

回答10:

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

回答11:

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

• /etc/my.cnf

回答12:

Found mine using

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

回答13:

Another option is to use the whereis command.

E.g. whereis my.cnf

回答14:

All great suggestions, in my case I didn\'t find it in any of those locations, but in /usr/share/mysql, I have a RHEL VM and I installed mysql5.5

回答15:

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

回答16:

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.

回答17:

Answered for only MySQL Workbench users,

回答18:

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.