Difference between revisions of "MySQL"
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[[fr:MySQL]] | [[fr:MySQL]] | ||
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+ | [[zh-CN:MySQL]] | ||
MySQL is a widely spread, multi-threaded, multi-user SQL database. For more information about features, see the [http://www.mysql.com/ official homepage]. | MySQL is a widely spread, multi-threaded, multi-user SQL database. For more information about features, see the [http://www.mysql.com/ official homepage]. | ||
== Installation == | == Installation == | ||
− | Install the mysql package | + | [[pacman|Install]] the {{Pkg|mysql}} package from the [[Official Repositories|official repositories]]. |
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− | + | After installing MySQL, start the ''mysqld'' [[Daemons|daemon]]. | |
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− | # systemctl | + | Run the setup script and restart the daemon afterwards: |
+ | # mysql_secure_installation | ||
+ | # systemctl restart mysqld | ||
== Configuration == | == Configuration == | ||
Once you have started the MySQL server, you probably want to add a root account in order to maintain your MySQL users and databases. This can be done manually or automatically, as mentioned by the output of the above script. Either run the commands to set a password for the root account, or run the secure installation script. | Once you have started the MySQL server, you probably want to add a root account in order to maintain your MySQL users and databases. This can be done manually or automatically, as mentioned by the output of the above script. Either run the commands to set a password for the root account, or run the secure installation script. | ||
− | You now should be able to do further configuration using your favorite interface. For example you can use MySQL's command line tool to | + | You now should be able to do further configuration using your favorite interface. For example you can use MySQL's command line tool to log in as root into your MySQL server: |
$ mysql -p -u root | $ mysql -p -u root | ||
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=== Enable remote access === | === Enable remote access === | ||
− | The MySQL server | + | The MySQL server is not accessable from the network by default. To enable listing on TCP port 3306 to allow remote connections, comment out the following line in {{ic|/etc/mysql/my.cnf}}: |
skip-networking | skip-networking | ||
+ | |||
+ | === Enable auto-completion === | ||
+ | The MySQL client completion feature is disabled by default. To enable it system-wide edit {{ic|/etc/mysql/my.cnf}}, and replace {{ic|no-auto-rehash}} by {{ic|auto-rehash}}. Completion will be enabled next time you run the MySQL client. Please note that enabling this feature can make the client initialization longer. | ||
== Upgrading == | == Upgrading == | ||
− | + | You might consider running this command after you have upgraded MySQL and started it: | |
# mysql_upgrade -u root -p | # mysql_upgrade -u root -p | ||
− | == | + | == Backup == |
− | + | The database can be dumped to a file for easy backup. The following shell script will do this for you, creating a {{ic|db_backup.gz}} file in the same directory as the script, containing your database dump: | |
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− | + | {{bc|1= | |
− | + | #!/bin/bash | |
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− | + | THISDIR=`dirname $(readlink -f "$0")` | |
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− | + | mysqldump --single-transaction --flush-logs --master-data=2 --all-databases \ | |
− | + | <nowiki>|</nowiki> gzip > $THISDIR/db_backup.gz | |
− | + | echo 'purge master logs before date_sub(now(), interval 7 day);' <nowiki>|</nowiki> mysql | |
− | + | }} | |
− | + | See also the official [http://dev.mysql.com/doc/refman/5.6/en/mysqldump.html mysqldump page in the MySQL manual]. | |
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== Troubleshooting == | == Troubleshooting == | ||
− | === | + | === MySQL daemon cannot start === |
If you see something like this: | If you see something like this: | ||
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:: Starting MySQL [FAIL] | :: Starting MySQL [FAIL] | ||
− | and no entry in log files, you might check | + | and there is no entry in the log files, you might want to check the permissions of files in the directories {{ic|/var/lib/mysql}} and {{ic|/var/lib/mysql/mysql}}. If the owner of files in these directories is not {{ic|mysql:mysql}}, you should do the following: |
# chown mysql:mysql /var/lib/mysql -R | # chown mysql:mysql /var/lib/mysql -R | ||
− | If you run into permission problems despite having followed the above ensure that your {{ | + | If you run into permission problems despite having followed the above, ensure that your {{ic|my.cnf}} is copied to {{ic|/etc/}}: |
# cp /etc/mysql/my.cnf /etc/my.cnf | # cp /etc/mysql/my.cnf /etc/my.cnf | ||
− | Now try and | + | Now try and start the daemon. |
− | If you get these messages in your {{ | + | If you get these messages in your {{ic|/var/lib/mysql/hostname.err}} |
[ERROR] Can't start server : Bind on unix socket: Permission denied | [ERROR] Can't start server : Bind on unix socket: Permission denied | ||
[ERROR] Do you already have another mysqld server running on socket: /var/run/mysqld/mysqld.sock ? | [ERROR] Do you already have another mysqld server running on socket: /var/run/mysqld/mysqld.sock ? | ||
[ERROR] Aborting | [ERROR] Aborting | ||
− | + | The permissions of {{ic|/var/run/mysqld}} could be the culprit. | |
# chown mysql:mysql /var/run/mysqld -R | # chown mysql:mysql /var/run/mysqld -R | ||
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If you run mysqld and the following error appears: | If you run mysqld and the following error appears: | ||
Fatal error: Can’t open and lock privilege tables: Table ‘mysql.host’ doesn’t exist | Fatal error: Can’t open and lock privilege tables: Table ‘mysql.host’ doesn’t exist | ||
− | Run the following command to install the default tables: | + | Run the following command from the /usr directory to install the default tables: |
+ | # cd /usr | ||
# mysql_install_db --user=mysql --ldata=/var/lib/mysql/ | # mysql_install_db --user=mysql --ldata=/var/lib/mysql/ | ||
− | === Unable to run mysql_upgrade because MySQL cannot start | + | === Unable to run mysql_upgrade because MySQL cannot start === |
Try run MySQL in safemode: | Try run MySQL in safemode: | ||
# mysqld_safe --datadir=/var/lib/mysql/ | # mysqld_safe --datadir=/var/lib/mysql/ | ||
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# mysql_upgrade -u root -p | # mysql_upgrade -u root -p | ||
− | === | + | === Reset the root password === |
− | Stop mysqld daemon | + | Stop the ''mysqld'' [[Daemons|daemon]]. |
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# mysqld_safe --skip-grant-tables & | # mysqld_safe --skip-grant-tables & | ||
− | Connect to mysql server | + | Connect to the mysql server |
# mysql -u root mysql | # mysql -u root mysql | ||
Change root password: | Change root password: | ||
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mysql> FLUSH PRIVILEGES; | mysql> FLUSH PRIVILEGES; | ||
mysql> exit | mysql> exit | ||
− | + | Start the ''mysqld'' daemon. | |
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− | == | + | == See also == |
+ | * [[MariaDB]] | ||
* [[LAMP]] - Arch wiki article covering the setup of a LAMP server (Linux Apache MySQL PHP) | * [[LAMP]] - Arch wiki article covering the setup of a LAMP server (Linux Apache MySQL PHP) | ||
* http://www.mysql.com/ | * http://www.mysql.com/ | ||
− | * | + | * Front-ends: {{AUR|mysql-gui-tools}} {{AUR|mysql-workbench}} |
Revision as of 00:10, 16 February 2013
zh-CN:MySQL MySQL is a widely spread, multi-threaded, multi-user SQL database. For more information about features, see the official homepage.
Contents
Installation
Install the mysql package from the official repositories.
After installing MySQL, start the mysqld daemon.
Run the setup script and restart the daemon afterwards:
# mysql_secure_installation # systemctl restart mysqld
Configuration
Once you have started the MySQL server, you probably want to add a root account in order to maintain your MySQL users and databases. This can be done manually or automatically, as mentioned by the output of the above script. Either run the commands to set a password for the root account, or run the secure installation script.
You now should be able to do further configuration using your favorite interface. For example you can use MySQL's command line tool to log in as root into your MySQL server:
$ mysql -p -u root
Enable remote access
The MySQL server is not accessable from the network by default. To enable listing on TCP port 3306 to allow remote connections, comment out the following line in /etc/mysql/my.cnf
:
skip-networking
Enable auto-completion
The MySQL client completion feature is disabled by default. To enable it system-wide edit /etc/mysql/my.cnf
, and replace no-auto-rehash
by auto-rehash
. Completion will be enabled next time you run the MySQL client. Please note that enabling this feature can make the client initialization longer.
Upgrading
You might consider running this command after you have upgraded MySQL and started it:
# mysql_upgrade -u root -p
Backup
The database can be dumped to a file for easy backup. The following shell script will do this for you, creating a db_backup.gz
file in the same directory as the script, containing your database dump:
#!/bin/bash THISDIR=`dirname $(readlink -f "$0")` mysqldump --single-transaction --flush-logs --master-data=2 --all-databases \ | gzip > $THISDIR/db_backup.gz echo 'purge master logs before date_sub(now(), interval 7 day);' | mysql
See also the official mysqldump page in the MySQL manual.
Troubleshooting
MySQL daemon cannot start
If you see something like this:
:: Starting MySQL [FAIL]
and there is no entry in the log files, you might want to check the permissions of files in the directories /var/lib/mysql
and /var/lib/mysql/mysql
. If the owner of files in these directories is not mysql:mysql
, you should do the following:
# chown mysql:mysql /var/lib/mysql -R
If you run into permission problems despite having followed the above, ensure that your my.cnf
is copied to /etc/
:
# cp /etc/mysql/my.cnf /etc/my.cnf
Now try and start the daemon.
If you get these messages in your /var/lib/mysql/hostname.err
[ERROR] Can't start server : Bind on unix socket: Permission denied [ERROR] Do you already have another mysqld server running on socket: /var/run/mysqld/mysqld.sock ? [ERROR] Aborting
The permissions of /var/run/mysqld
could be the culprit.
# chown mysql:mysql /var/run/mysqld -R
If you run mysqld and the following error appears:
Fatal error: Can’t open and lock privilege tables: Table ‘mysql.host’ doesn’t exist
Run the following command from the /usr directory to install the default tables:
# cd /usr # mysql_install_db --user=mysql --ldata=/var/lib/mysql/
Unable to run mysql_upgrade because MySQL cannot start
Try run MySQL in safemode:
# mysqld_safe --datadir=/var/lib/mysql/
And then run:
# mysql_upgrade -u root -p
Reset the root password
Stop the mysqld daemon.
# mysqld_safe --skip-grant-tables &
Connect to the mysql server
# mysql -u root mysql
Change root password:
mysql> UPDATE mysql.user SET Password=PASSWORD('MyNewPass') WHERE User='root'; mysql> FLUSH PRIVILEGES; mysql> exit
Start the mysqld daemon.
See also
- MariaDB
- LAMP - Arch wiki article covering the setup of a LAMP server (Linux Apache MySQL PHP)
- http://www.mysql.com/
- Front-ends: mysql-gui-toolsAUR mysql-workbenchAUR