MySQL

MySQL is the most popular database manager in free software for two simple reasons (which are not the best technical reasons):
# It's simple and very easy to use
# It is very similar to SQLSERVER and is also used in other systems
In the world of Linux Alpine there is a software that provides it, it is the MariaDB, here we have a brief of info about compatibility and differences, but in short there's no great differences, if you have doubts check MariaDB vs MySQL section here
In the wiki there are two approaches for its use, the professional one (for servers and deploys) and the fast and simple usage (for developers and/or enthusiasts):
= MariaDB - fast and simple use =
= MySQL (MariaDB) - Production usage =
MariaDB is a community-developed fork of the MySQL relational database management system intended to remain free under the GNU GPL. It is notable for being led by the original developers of MySQL, who forked it due to concerns over its acquisition by Oracle.
This page assumed that you have a general knowledge about MariaDB, so if you are new to MySQL first take a look at the MariaDB wiki page for information about how are packaged for alpine linux.
== Installation ==
Alpine Linux has dummy counterparts packages for those that are not close to that change from mysql to mariadb naming packages, please check the MariaDB wiki page for more information.
Take in consideration that the user mysql was created during instalation of packages, in the initialization section two users will be created in database init: root and mysql, and in that point only if are in their respective system accounts, will be able to connect to the database service.
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apk add mysql mysql-client
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That will install the most used ones.. mariadb-cient and mariadb-server, rest of packages are brief described here for more information, here are listed in orden of relevance for production server
MySQL name package 	Since Alpine:	Brief usage 	Related package
mysql 	v2 	it's a dummy package to easy install of mariadb 	mariadb
mysql-client 	v2 	it's a dummy package to easy install of commands tools 	mariadb-client
mariadb 	v2 	server equivalent to mysql-server 	mariadb-common
mariadb-client 	v2 	connection command line and tools 	mariadb-common
mariadb-doc 	v3.0 	manpages are there! 	man man-pages
mariadb-connector-odbc	edge 	coding or making OS level connections, to any DB without libs install 	.
mariadb-connector-c 	v3.8 	coding connection on C sources 	mariadb-connector-c-dev
mariadb-backup 	v3.8 	to external backup devices, not widely used, in past was inside mariadb package	.
mariadb-server-utils 	v3.8 	server commands not widely used, in past was inside mariadb package 	.
mariadb-dev 	v3.1 	Need for compilations depends on source code 	.
mariadb-test 	v3.3 	testing suite from MariaDB tools 	.
mariadb-mytop 	v3.9 	data performance monitoring 	.
mariadb-plugin-rocksdb	v3.9 	plain key-value event relational for data 	.
mariadb-static 	v3.8 	static libs for static non depends linking in builds 	.
mariadb-embedded 	v3.9 	the libmysqld identical interface as the C client 	mariadb-embedded-dev
mariadb-embedded-dev 	v3.9 	use the normal mysql.h and link with libmysqld instead of libmysqlclient 	mariadb-dev
mariadb-openrc 	v3.8 	separate scripts, in past was embebed on server package 	.
== Initialization ==
The alpine package of MySQL/MariaDB are like normal tarball of MySQL one, admins must be know what they want.. there's no automatic window-like here.
The datadir are located to /var/lib/mysql must be owned by the mysql user and group. You can modify this behavior but must edit the service file at /etc/init.d directory. Also, you need to set datadir=<YOUR_DATADIR> under section [mysqld] at the config file.
# Initialize the main mysql database, and the data dir as standardized to /var/lib/mysql by the rc script
# Then initialize the service, root account and socket connection are enabled without password at this point
# Setup the root account by asignes a proper password, this are purely paranoid. due next step already do that!
# Setup and init the installation by running the mysql_secure_installation
# Setup permissions for manage others users and databases
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mysql_install_db --user=mysql --datadir=/var/lib/mysql
rc-service mariadb start
mysqladmin -u root password toor
</nowiki>
After that, all are initializated to proceed with configuration, now can be done using the 
mysql_secure_installation script at the next section:
== Configuration ==
In order to finish setup into MariaDB now provide this script called mysql_secure_instalation that also are present as mariadb-secure-installation, too. This script provides minimal and security setup to the database, and here are the questions made explained:
# Enter current password for root (enter for none): this are if you previously setup as we done in previous section a root password, just provide it and press enter, must be provided due we already set previously and from now, this sript will access to the engine and alter many setting on the database. Correct respond are OK, successfully used password, moving on...
# Switch to unix_socket authentication [Y/n] Setting the root password or using the unix_socket ensures that only admins can log into engine database. Since mysql 5.6 and mariadb 10.2 a new auth mechanish are set, by socket authentiaction, when system user are same as mysql/mariadb user, in this case, no password are need. In production servers this are not the case and must be disabled, so answer NO, and response will be ... skipping.
# Change the root password? [Y/n] this answer are here only if the first one are just enter, or if can provide a better passowrd if no unix socket are set. Just press "n" only if you provided a good password, otherwise just 
# Remove anonymous users? [Y/n] this permits remove the anonymous user created to log using socket authentication, only working on unix-like system. In any case, production system must remove it, so answer Y and proper respond must be ... Success!.
# Disallow root login remotely? [Y/n] Normally, root should only be allowed to connect from 'localhost'. This ensures that someone cannot guess at the root password from the network. For sure answer Y and proper respond must be ... Success!.
# Remove test database and access to it? [Y/n] By default, MariaDB comes with a database named 'test' that anyone can access. This is also intended only for testing, and should be removed, so answer Y and proper respond must be ... Success!.
# Reload privilege tables now? [Y/n] Reloading the privilege tables will ensure that all changes made so far will take effect immediately, so answer Y and proper respond must be ... Success!.
After reponse all the questions.. restart the service with rc-service mariadb restart
=== Configuration files ===
Due today were influenced by systemd standardization, the famous my.cnf are not more the main config file for the server engine. Now only few variables are defined there and all the settings are provided by independent files into the /etc/my.cnf.d/ directory, user own config files are under ~/.my.cnf config file of each home dir, and are read after global ones; so then we have:
Config file 	Path and name 	Versions of Alpine	Contents to configure
my.cnf 	/etc/mysql/my.cnf 	v2 to v3.8 	All the directives, Global config file
mariadb-server.cnf	/etc/my.cnf.d/mariadb-server.cnf	since 3.9 	First Global config file, main directives
.my.cnf 	$HOME 	all 	user name only config directives
=== Production settings ===
These setting are only recommended for some server settings, there are the recommendation for high production settings:
Config setting 	Default 	Recommended 	Explanation
main ram 	2G 	8G - 16G 	MariaDB/MySQL can run with 512M or 1G of ram, high production must use minimun of 4G or more.
data dir disk type 	any 	SSD 	MariaDB/MySQL must run with faster SSD if high request will be produced.
collation_server 	utf8_unicode_ci	utf8mb4_unicode_ci	With 8mb4 some characters are able to use more than a single byte.
character_set_client 	iso8859-1 	utf8 or utf8mb4 	Important due are standard, for left to right use 8mb4 flavor
max_connections 	151 	100 	total_connections = total_processes * (total_threads + script_servers + 1)
max_heap_table_size 	16M 	32M 	allocate more memory to memory tables, for memory storage engines
tmp_table_size 	16M 	32M 	It allows the sub queries to remain more in memory, making them faster
join_buffer_size 	32M 	64M 	It allows the join queries to remain more in memory rather in temp files
innodb_file_format 	unset 	Barracuda 	will allow longer indexes for important most used tables
innodb_large_prefix 	unset 	1 	Must set if Barracuda file format are choosen
innodb_buffer_pool_size 	128M 	456M 	hold as much tables and indexes in system memory as is possible
innodb_read_io_threads 	16 	32 	On high I/O systems, a value greater than 1 may allow the disk I/O to be more sequential
innodb_write_io_threads 	16 	32 	Only if you have SSD storage for the data MySQL/MariaDB database and temp files
innodb_buffer_pool_instances	1 	2 or 4 	Only for older MySQL/MariaDB engines,
innodb_io_capacity 	200 	1200 - 2600 	Only if you have SSD storage for the data MySQL/MariaDB database and temp files
innodb_io_capacity_max 	200 	2400 - 5200 	Only if you have SSD storage for the data MySQL/MariaDB database and temp files
If you have SSD disks, use the recommended suggestion, otherwise, use minimum suggested. If you have physical hard drives, use 2000 * the number of active drives in the array. If using NVMe or PCIe Flash, much larger numbers as high as 200000 can be used, but those lasted storage devices will be a short life of course.
Newer system Alpine packages can set in independent files in any case those commands always works and where are not apply just will ignore the output:
* On older Alpine system must set config files for MAX ALLOWED PACKETS to minimun proper amount:
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sed -i "s|.*max_allowed_packet\s*=.*|max_allowed_packet = 100M|g" /etc/mysql/my.cnf
sed -i "s|.*max_allowed_packet\s*=.*|max_allowed_packet = 100M|g" /etc/my.cnf.d/mariadb-server.cnf
</nowiki>
* Only allow local connections on cases where there's only one server or no expected to connect from others:
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sed -i "s|.*bind-address\s*=.*|bind-address=127.0.0.1|g" /etc/mysql/my.cnf
sed -i "s|.*bind-address\s*=.*|bind-address=127.0.0.1|g" /etc/my.cnf.d/mariadb-server.cnf
</nowiki>
* If are not in domain controller, dont search for hostnames to improve performance responses (ideal for local only servers):
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sed -i "s|.*skip-networking.*|skip-networking|g" /etc/mysql/my.cnf
sed -i "s|.*skip-networking.*|skip-networking|g" /etc/my.cnf.d/mariadb-server.cnf
</nowiki>
* Set default charset to UTF8MB4, in newer versions (since Alpine v3.9), just added a new file to added thus customization, but older versions (below Alpine v3.8)of the package does not have a charset section, so you must added manually to the main configuration in each respective section:
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cat > /etc/my.cnf.d/mariadb-server-default-charset.cnf << EOF
[client]
default-character-set = utf8mb4
[mysqld]
collation_server = utf8mb4_unicode_ci
character_set_server = utf8mb4
[mysql]
default-character-set = utf8mb4
EOF
</nowiki>
== Updating or comming from upgrading ==
Mayor Upgrades beetween Alpine linux version are so easy as change the repository version, but the MySQL/MariaDB engine need some extra steps when this are performed:
Upgrade databases on major releases
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:
# keep the old database (mysql sheme) structure of the engine daemon, currently this are not more the case, today this not make sense anymore
# upgrade the MariaDB/MySQL packages, of course with must be done if the upgrade process to mayor alpine version does not!
# run the mysql_upgrade -u root -p script, providing the password or root, (from the new package version) against the old still-running database (mysql sheme). This will produce some error messages; however, the upgrade will succeed.
# Restart the service
If are unable to run mysql_upgrade because MySQL cannot start try run MySQL in safemode with mysqld_safe --datadir=/var/lib/mysql/ command and then run the mysql_upgrade -u root -p script.
= Relevant important notes =
== File system notes about the databases managed ==
Btrfs Notes 
If the database (in /var/lib/mysql) resides on a btrfs file system, you should consider disabling Copy-on-Write for the directory before creating any database (schemes), after initialization you can enabled again. But .. on every database creation (scheme creation), you must disabled again, to avoid corrupted data.
ZFS Bock sizes
ZFS, unlike most other file systems, has a variable record size, or what is commonly referred to as a block size. By default, the recordsize on ZFS is 128KiB, which means it will dynamically allocate blocks of any size from 512B to 128KiB depending on the size of file being written. Most RDBMSes work in 8KiB-sized blocks by default. Although the block size is tunable for MySQL/MariaDB use an 8KiB block size by default.
It is usually desirable to tune ZFS instead to accommodate the databases, using a command such as zfs set recordsize=8K /var/lib/mysql (or change /var/lib/mysql to the mount point where /var/lib/mysql resides) and in the interest of saving memory, it is best to simply disable ZFS's caching of the database's file data and let the database do its own job with zfs set primarycache=metadata /var/lib/mysql (or change /var/lib/mysql to the mount point where /var/lib/mysql resides).
But beware, these kinds of tuning parameters are only if RDBMSes are setup in dedicated partitions, if your root and of course database are all in one partition, dont do that. Separate ones.
== Restore root password ==
<nowiki>
rc-service mysql stop
kill `cat /run/mysqld/mysqld.pid`
/usr/bin/mysqld --datadir=/var/lib/mysql --pid-file=/run/mysqld/mysqld.pid --skip-grant-tables --skip-networking &
mysql -e "ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';FLUSH PRIVILEGES;ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';FLUSH PRIVILEGES;set password = password('MyNewPass');"
kill `cat /run/mysqld/mysqld.pid`
rc-service mariadb restart
</nowiki>
= See Also =
* MariaDB wiki page
* Production LAMP system: Lighttpd + PHP + MySQL
Category:Newbie
Category:Server
Category:Database
Category:Development
Category:Security
Category:Production
= MariaDB vs MySQL =
It is more a matter of compatibility than of performance and characteristics (with the arrival of MySQL v8) .. and it depends on whether there is a purely business and support approach "zero concern".
MySQL, being from Oracle, establishes limits if a license is not purchased, MariaDB has a large connection pool, more than 200,000 connections, while MySQL has a smaller connection pool if it is not licensed.
However, MariaDB does not support data masking and dynamic column while MySQL supports it, also MariaDB although it has 12 new storage engines while MySQL has less these are very new and MySQL's are widely known and tested.
In terms of performance, MariaDB is only a little faster than MySQL, this is because MySQL implements more business features, but this is only noticeable using these many features.
Which is more optimal this is not clear .. in general MySQL should be less, and MariaDB faster, there is a third option which is Percona which is the same MySQL service but with special aggressive optimization patches for servers. Percona mysql code must be compiled in Alpine linux.
== Comparison table ==
Characteristic 	MariaDB 	MySQL
Storage Engines 	up to 12 but many in development stage	less but well tested
Performance 	just a little faster 	less, there is almost no difference
Initial version 	2009 (5.3) 	1995 (3.0)
Data masking 	no 	yes
dynamic columns 	no 	yes
Monitoring 	SQLyog 	MySQLworkbench
Routing 	MariaDB MaxScale 	Mysql Router
Analytics 	MariaDB ColumnStore 	not have
Git starred times (github)	around 3.6k 	around 6k
For more info check a review here: http://qgqlochekone.blogspot.com/2020/04/mariadb-mysql-and-mysqlworkbench.html
Category:Newbie
Category:Server
Category:Database
Category:Development