MariaDB

Creating a new user takes two steps: create the user; grant privileges. In the below example, the user monty with some_pass as password is being created, then granted full permissions to the database mydb:

MariaDB configuration options are read from the following files in the given order (according to output):

/etc/my.cnf /etc/my.cnf.d/ ~/.my.cnf

Depending on the scope of the changes you want to make (system-wide, user-only...), use the corresponding file. See this entry of the Knowledge Base for more information.

The MySQL client completion feature is disabled by default. To enable it system-wide edit , and add under mysql. Note that this must not be placed under . Completion will be enabled next time you run the MySQL client.

Append the following values to the main configuration file located at :

Restart mariadb.service to apply the changes.

See #Maintenance to optimize and check the database health.

For InnoDB execute the following commands to support a higher character-limit:

mysql> set global innodb_file_format = BARRACUDA;
Query OK, 0 rows affected (0.00 sec)

mysql> set global innodb_file_per_table = ON;
Query OK, 0 rows affected (0.00 sec)

mysql> set global innodb_large_prefix = ON;
Query OK, 0 rows affected (0.00 sec)

Append the following lines in to always use a higher character-limit:

[mysqld]
innodb_file_format = barracuda
innodb_file_per_table = 1
innodb_large_prefix = 1

Restart mariadb.service to apply the changes.

On table creating append the as seen in the example:

mysql> create table if not exists products (
   ->   day date not null,
   ->   product_id int not null,
   ->   dimension1 varchar(500) not null,
   ->   dimension2 varchar(500) not null,
   ->   unique index unique_index (day, product_id, dimension1, dimension2)
   -> ) ENGINE=InnoDB ROW_FORMAT=DYNAMIC;
Query OK, 0 rows affected (0.02 sec)

The directory used by MySQL for storing temporary files is named tmpdir. For example, it is used to perform disk based large sorts, as well as for internal and explicit temporary tables.

Create the directory with appropriate permissions:

# mkdir -pv /var/lib/mysqltmp
# chown mysql:mysql /var/lib/mysqltmp

Add the following tmpfs mount to your file:

tmpfs   /var/lib/mysqltmp   tmpfs   rw,gid=mysql,uid=mysql,size=100M,mode=0750,noatime   0 0

Add to your file under the group:

tmpdir      = /var/lib/mysqltmp

Stop mariadb.service, mount /var/lib/mysqltmp/ and start mariadb.service.

Although time zone tables are created during the installation, they are not automatically populated. They need to be populated if you are planning on using CONVERT_TZ() in SQL queries.

To populate the time zone tables with all the time zones:

$ mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root -p mysql

Optionally, you may populate the table with specific time zone files:

$ mysql_tzinfo_to_sql timezone_file timezone_name | mysql -u root -p mysql

The command will interactively guide you through a number of recommended security measures, such as removing anonymous accounts and removing the test database:

# mysql_secure_installation

By default, MySQL will listen on the 0.0.0.0 address, which includes all network interfaces. In order to restrict MySQL to listen only to the loopback address, add the following line in :

[mysqld]
bind-address = 127.0.0.1

By default, MySQL is accessible via both Unix sockets and the network. If MySQL is only needed for the localhost, you can improve security by not listening on TCP port 3306, and only listening on Unix sockets instead. To do this, add the following line in :

[mysqld]
skip-networking

You will still be able to log in locally as before, but only using Unix sockets.

To allow remote access to the MySQL server, ensure that MySQL has networking enabled and is listening on the appropriate interface.

Grant any MySQL user remote access (example for root):

# mysql -u root -p

Check current users with remote access privileged:

SELECT User, Host FROM mysql.user WHERE Host <> 'localhost';

Now grant remote access for your user (here root):

GRANT ALL PRIVILEGES ON *.* TO 'root'@'192.168.1.%' IDENTIFIED BY 'my_optional_remote_password' WITH GRANT OPTION;

You can change the '%' wildcard to a specific host if you like. The password can be different from user's main password.

For security reasons, the systemd service file contains , which prevents MariaDB from accessing files under the , and hierarchies. The datadir has to be in an accessible location and owned by the mysql user and group.

You can modify this behavior by creating a supplementary service file as described here.

Upon a major version release of mariadb (for example mariadb-10.1.10-1 to mariadb-10.1.18-1), it is wise to upgrade databases:

# mysql_upgrade -u root -p

To upgrade from 10.1.x to 10.3.x:

• keep the 10.1.x database daemon running
• upgrade the package
• run (from the new package version) against the old still-running daemon. This will produce some error messages; however, the upgrade will succeed.
• restart the daemon, so the 10.3.x daemon runs.

Alternatively, stop the (old) daemon, run the (new) daemon in safe mode, run against that, and then start the (new) daemon as described in #Unable to run mysql_upgrade because MySQL cannot start.

mariadb ships with which can be used to check, repair, and optimize tables within databases from the shell. See the mysqlcheck man page for more. Several command tasks are shown:

To check all tables in all databases:

$ mysqlcheck --all-databases -u root -p -c

To analyze all tables in all databases:

$ mysqlcheck --all-databases -u root -p -a

To repair all tables in all databases:

$ mysqlcheck --all-databases -u root -p -r

To optimize all tables in all databases:

$ mysqlcheck --all-databases -u root -p -o

As SQL tables can get pretty large, it is recommended to pipe the output of the aforementioned command in a compression utility like :

$ mysqldump --single-transaction --flush-logs --master-data=2 --all-databases -u root -p | gzip > all_databases.sql.gz

Decompressing the backup thus created and reloading it in the server is achieved by doing:

$ zcat all_databases.sql.gz | mysql -u root -p

This will recreate and repopulate all the databases previously backed up (see this or this).

If you want to setup non-interactive backup script for use in cron jobs or systemd timers, see option files and this illustration for mysqldump.

Basically you should add the following section to the relevant configuration file:

Mentioning a user here is optional, but doing so will free you from having to mention it on the command line. If you want to set this for all tools, including mysql, use the group.

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/sh

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 page in the MySQL and MariaDB manuals.

A python-based software package named Holland Backup is available in AUR to automate all of the backup work. It supports direct mysqldump, LVM snapshots to tar files (mysqllvm), LVM snapshots with mysqldump (mysqldump-lvm), and methods to extract the data. The Holland framework supports a multitude of options and is highly configurable to address almost any backup situation.

The main holland^AUR and packages provide the core framework; one of the sub-packages (, and/or must be installed for full operation. Example configurations for each method are in the directory and can be copied to , as well as using the holland mk-config command to generate a base configuration for a named provider.

Try run MySQL in safemode:

# mysqld_safe --datadir=/var/lib/mysql/

And then run:

# mysql_upgrade -u root -p

1. Stop mariadb.service.
2. Start the mysqld server with safety features:
3. Connect to it:
4. Change root password:
5. Kill running mysqld* processes:

   # kill $(cat /var/lib/mysql/$HOSTNAME.pid)

6. Start mariadb.service.

Check and auto repair all tables in all databases, see more:

# mysqlcheck -A --auto-repair -u root -p

Forcefully optimize all tables, automatically fixing table errors that may come up.

# mysqlcheck -A --auto-repair -f -o -u root -p

If using MySQL databases on ZFS, the error may occur.

A workaround is to disable in :

This may happen if you are using a long (>70-75) password. As for 5.5.36, for some reason, mysql CLI cannot handle that many characters in readline mode. So, if you are planning to use the recommended password input mode:

Consider changing the password to smaller one.

By default, mysqld creates binary log files in . This is useful for replication master server or data recovery. But these binary logs can eat up your disk space. If you do not plan to use replication or data recovery features, you may disable binary logging by commenting out these lines in :

#log-bin=mysql-bin
#binlog_format=mixed

Or you could limit the size of the logfile like this:

expire_logs_days = 10
max_binlog_size  = 100M

Alternatively, you can purge some binary logs in to free up disk space with this command:

# mysql -u root -p"PASSWORD" -e "PURGE BINARY LOGS TO 'mysql-bin.0000xx';"

To use MySQL with OpenRC you need to add the following lines to the [mysqld] section in the MySQL configuration file, located at .

user = mysql
basedir = /usr
datadir = /var/lib/mysql
pid-file = /run/mysqld/mysql.pid

You should now be able to start MySQL using:

# rc-service mysql start

See #Increase character limit.

Increase the number of file descriptors by creating a systemd drop-in, e.g.:

Before MariaDB 10.5, redo log was unnecessarily split into multiple files.

Move the old binary logs out of the way, thus letting MariaDB 10.5 create new ones. Then restart mariadb.service and upgrade your tables with .

MariaDB in its default configuration binds to and is only accessible using IPv4. If you want to connect from hosts using IPv6 exclusively you have to change the servers bind accordingly. will listen on IPv6 and IPv4.