Server System Variables - Source

<<toc>> == About Server System Variables MariaDB has a lot of system variables that can be changed to suit your needs. Most of these can be set with [[mysqld-options-full-list|command line options]]. There are a few ways to see the full list of server system variables: * While in the mysql client, run: <<code lang=mysql inline=false>> SHOW VARIABLES; <</code>> See [[show-variables|SHOW VARIABLES]] for instructions on using this command. * From your shell, run mysqld like so:<<code lang=sh inline=false>> mysqld --verbose --help <</code>> == Setting Server System Variables There are several ways to set server system variables: * Specify them on the command line: <<code lang=sh inline=false>> shell> ./mysqld_safe --aria_group_commit="hard" <</code>> * Specify them in your my.cnf file: <<code lang=sh inline=false>> aria_group_commit = "hard" <</code>> * Set them from the mysql client using the [[set|SET]] command: <<code lang=sql inline=false>> SET GLOBAL aria_group_commit="hard"; <</code>> == List of Server System Variables New variables in MariaDB are: === ##key_cache_segments## * **Description:** The number of segments in a key cache. * **Commandline:** <<code>>--key-cache-segments=#<</code>> * **Scope:** Global * **Dynamic:** Yes * **Type:** number * **Valid values:** <<code>>0-64<</code>> * **Default value:** <<code>>0<</code>> //(non-segmented)// * **Introduced:** MariaDB 5.2.0 ---- === ##aria_group_commit## * **Description:** Specifies aria group commit mode. * **Commandline:** <<code>>--aria_group_commit="value"<</code>> * **Alias:** ##maria_group_commit## * **Scope:** Global * **Dynamic:** No * **Type:** string * **Valid values:** ** ##none## - //Group commit is disabled.// ** ##hard## - //Wait the number of microseconds specified by aria_group_commit_interval before actually doing the commit. If the interval is 0 then just check if any other threads have requested a commit during the time this commit was preparing (just before sync() file) and send their data to disk also before sync().// ** ##soft## - //The service thread will wait the specified time and then sync() to the log. If the interval is 0 then it won't wait for any commits (this is dangerous and should generally not be used in production)// * **Default value:** ##none## * **Introduced:** MariaDB 5.2 ---- === ##aria_group_commit_interval## * **Description:** Interval between commits in microseconds (1/1000000c) for other threads to come and do a commit in "hard" mode and sync()/commit at all in "soft" mode. Option only has effect if ##aria_group_commit## is used. * **Commandline:** <<code>>--aria_group_commit_interval=# <</code>> * **Alias:** ##maria_group_commit_interval## * **Scope:** Global * **Dynamic:** No * **Type:** number * **Valid values:** ** **Default:** ##0## //(no waiting)// ** **32-bit systems:** ##0-4294967295## ** **64-bit systems:** ##0-18446744073709547520## * **Introduced:** MariaDB 5.2 ---- === ##plugin_maturity## * **Description:** The lowest acceptable plugin maturity. MySQL will not load plugins less mature than that. * **Commandline:** <<code>>--plugin-maturity=level<</code>> * **Scope:** Global * **Dynamic:** No * **Type:** enum * **Valid levels:** <<code>>unknown<</code>>, <<code>>experimental<</code>>, <<code>>alpha<</code>>, <<code>>beta<</code>>, <<code>>gamma<</code>>, <<code>>stable<</code>> * **Default value:** <<code>>unknown<</code>> * **Introduced:** MariaDB 5.2.1 ---- === ##binlog_checksum## * **Description:** Enable/Disable [[binlog-event-checksums|binlog checksums]]. * **Commandline:** <<code>>--binlog_checksum=[0|1]<</code>> * **Scope:** Global * **Access Type:** Can be changed dynamically * **Data Type:** ##bool## * **Default Value:** ##OFF (0)## * **Introduced:** MariaDB 5.3 ---- === ##master_verify_checksum## * **Description:** Verify [[binlog-event-checksums|binlog checksums]] when reading events from the binlog on the master. * **Commandline:** <<code>>--master_verify_checksum=[0|1]<</code>> * **Scope:** Global * **Access Type:** Can be changed dynamically * **Data Type:** ##bool## * **Default Value:** ##OFF (0)## * **Introduced:** MariaDB 5.3 ---- === ##slave_sql_verify_checksum## * **Description:** Verify [[binlog-event-checksums|binlog checksums]] when the slave SQL thread reads events from the relay log. * **Commandline:** <<code>>--slave_sql_verify_checksum=[0|1]<</code>> * **Scope:** Global * **Access Type:** Can be changed dynamically * **Data Type:** ##bool## * **Default Value:** ##ON (1)## * **Introduced:** MariaDB 5.3 ---- Other Variables are the same as in MySQL. See [[http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html|Server System Variables]] in the MySQL Manual for the full list of MySQL server system variables.