MariaDB has many system variables that can be changed to suit your needs.
For a full list of server options, system variables and status variables, see this page.
Many of the general system variables are described on this page, but others are described elsewhere:
See also the Full list of MariaDB options, system and status variables.
Most of these can be set with command line options and many of them can be changed at runtime. Variables that can be changed at runtime (and therefore are not read-only) are described as "Dynamic" below, and elsewhere in the documentation.
There are a few ways to see the full list of server system variables:
While in the mariadb client, run:
From your shell, run mariadbd like so:
mariadbd --verbose --helpThere are several ways to set server system variables:
Specify them on the command line:
shell> ./mariadbd-safe --aria_group_commit="hard"aria_group_commit = "hard"Set them from the mariadb client using the SET command. Only variables that are dynamic can be set at runtime in this way. Note that variables set in this way will not persist after a restart.
SET GLOBAL aria_group_commit="hard";By convention, server variables have usually been specified with an underscore in the configuration files, and a dash on the command line. You can however specify underscores as dashes - they are interchangeable.
Variables that take a numeric size can either be specified in full, or with a suffix for easier readability. Valid suffixes are:
The suffix can be upper or lower-case.
List of Server System VariablesDescription: Allows use of user-defined functions consisting of only one symbol x() without corresponding x_init() or x_deinit(). That also means that one can load any function from any library, for example exit() from libc.so. Not recommended unless you require old UDFs with one symbol that cannot be recompiled. Before MariaDB 10.10, available as an option only.
Command line: --allow-suspicious-udfs
Description: The implied ALGORITHM for ALTER TABLE if no ALGORITHM clause is specified. The deprecated variable old_alter_table is an alias for this. The feature was removed in MariaDB 11.5. See ALGORITHM=DEFAULT.
COPY corresponds to the pre-MySQL 5.1 approach of creating an intermediate table, copying data one row at a time, and renaming and dropping tables.
INPLACE requests that the operation be refused if it cannot be done natively inside a the storage engine.
DEFAULT (the default) chooses INPLACE if available, and falls back to COPY.
NOCOPY refuses to copy a table.
INSTANT refuses an operation that would involve any other than metadata changes.
Command line: --alter-algorithm=default
Valid Values: DEFAULT, COPY, INPLACE, NOCOPY, INSTANT
Command line: --analyze-max-length=val
Default Value: 4294967295 (4G)
analyze_sample_percentage
Description: Percentage of rows from the table ANALYZE TABLE will sample to collect table statistics. Set to 0 to let MariaDB decide what percentage of rows to sample.
Command line: --analyze-sample-percentage=#
Default Value: 100.000000
Description: If set to 1, the default, all queries are committed immediately. The LOCK IN SHARE MODE and FOR UPDATE clauses therefore have no effect. If set to 0, they are only committed upon a COMMIT statement, or rolled back with a ROLLBACK statement. If autocommit is set to 0, and then changed to 1, all open transactions are immediately committed.
Command line: --autocommit[=#]
Description: When set to 1, the default, when a stored routine is created, the creator is automatically granted permission to ALTER (which includes dropping) and to EXECUTE the routine. If set to 0, the creator is not automatically granted these privileges.
Command line: --automatic-sp-privileges, --skip-automatic-sp-privileges
Description: Connections take a small amount of time to start, and this setting determines the number of outstanding connection requests MariaDB can have, or the size of the listen queue for incoming TCP/IP requests. Requests beyond this will be refused. Increase if you expect short bursts of connections. Cannot be set higher than the operating system limit (see the Unix listen() man page). If not set, set to 0, or the --autoset-back-log option is used, will be autoset to the lower of 900 and (50 + max_connections/5).
Command line: --back-log=#
Description: Path to the MariaDB installation directory. Other paths are usually resolved relative to this base directory.
Command line: --basedir=path or -b path
Description: If this system variable is set to 1, then temporary tables will be saved to disk intead of memory.
This system variable's original intention was to allow result sets that were too big for memory-based temporary tables and to avoid the resulting 'table full' errors.
This system variable is no longer needed, because the server can automatically convert large memory-based temporary tables into disk-based temporary tables when they exceed the value of the tmp_memory_table_size system variable.
To prevent memory-based temporary tables from being used at all, set the tmp_memory_table_size system variable to 0.
Command line: --big-tables
Description: By default, the MariaDB server listens for TCP/IP connections on all addresses. You can specify an alternative when the server starts using this option; either a host name, an IPv4 or an IPv6 address, "::" or "" (all addresses). In some systems, such as Debian and Ubuntu, the bind_address is set to 127.0.0.1, which binds the server to listen on localhost only. bind_address has always been available as a mariadbd option; from MariaDB 10.3.3 its also available as a system variable. Before MariaDB 10.6.0 "::" implied listening additionally on IPv4 addresses like "". From 10.6.0 onwards it refers to IPv6 stictly. Starting with MariaDB 10.11, a comma-separated list of addresses to bind to can be given. See also Configuring MariaDB for Remote Client Access.
Command line: --bind-address=addr
Default Value: (Empty string)
Valid Values: Host name, IPv4, IPv6, ::, *
Command line: --block-encryption-mode=val
Default Value: aes-128-ecb
Valid values: aes-128-ecb, aes-192-ecb, aes-256-ecb, aes-128-cbc, aes-192-cbc, aes-256-cbc, aes-128-ctr, aes-192-ctr, aes-256-ctr
Description: Size in bytes of the per-thread cache tree used to speed up bulk inserts into MyISAM and Aria tables. A value of 0 disables the cache tree.
Command line: --bulk-insert-buffer-size=#
Range - 32 bit: 0 to 4294967295
Range - 64 bit: 0 to 18446744073709547520
Description: Determines the character set for queries arriving from the client. It can be set per session by the client, although the server can be configured to ignore client requests with the --skip-character-set-client-handshake option. If the client does not request a character set, or requests a character set that the server does not support, the global value will be used. utf16, utf16le, utf32 and ucs2 cannot be used as client character sets. From MariaDB 10.6, the utf8 character set (and related collations) is by default an alias for utf8mb3 rather than the other way around. It can be set to imply utf8mb4 by changing the value of the old_mode system variable.
Description: Overrides for character set default collations. Takes a comma-delimited list of character set and collation settings, for example SET @@character_set_collations = 'utf8mb4=uca1400_ai_ci, latin2=latin2_hungarian_ci'; The new variable will take effect in all cases where a character set is explicitly or implicitly specified without an explicit COLLATE clause, including but not limited to:
CONVERT(expr USING csname)
CAST(expr AS CHAR CHARACTER SET csname)
'' - character string literal
_utf8mb3'text' - a character string literal with an introducer
_utf8mb3 X'61' - a character string literal with an introducer with hex notation
_utf8mb3 0x61 - a character string literal with an introducer with hex hybrid notation
@@collation_connection after a SET NAMES without COLLATE
Default Value:
utf8mb3=utf8mb3_uca1400_ai_ci, ucs2=ucs2_uca1400_ai_ci, utf8mb4=utf8mb4_uca1400_ai_ci, utf16=utf16_uca1400_ai_ci, utf32=utf32_uca1400_ai_ci (>= MariaDB 11.5)
Description: Character set used for number to string conversion, as well as for literals that don't have a character set introducer. From MariaDB 10.6, the utf8 character set (and related collations) is by default an alias for utf8mb3 rather than the other way around. It can be set to imply utf8mb4 by changing the value of the old_mode system variable.
Description: Character set used by the default database, and set by the server whenever the default database is changed. If there's no default database, character_set_database contains the same value as character_set_server. This variable is dynamic, but should not be set manually, only by the server.
Description: The character set for the filesystem. Used for converting file names specified as a string literal from character_set_client to character_set_filesystem before opening the file. By default set to binary, so no conversion takes place. This could be useful for statements such as LOAD_FILE() or LOAD DATA INFILE on system where multi-byte file names are use.
Command line: --character-set-filesystem=name
Description: Character set used for results and error messages returned to the client. From MariaDB 10.6, the utf8 character set (and related collations) is by default an alias for utf8mb3 rather than the other way around. It can be set to imply utf8mb4 by changing the value of the old_mode system variable.
Command line: --character-set-server
Description: Character set used by the server to store identifiers, always set to utf8, or its synonym utf8mb3 starting with MariaDB 10.6. From MariaDB 10.6, the utf8 character set (and related collations) is by default an alias for utf8mb3 rather than the other way around. It can be set to imply utf8mb4 by changing the value of the old_mode system variable.
Command line: --character-sets-dir=path
Description: If set to 0, will disable constraint checks, for example when loading a table that violates some constraints that you plan to fix later.
Description: Collation used for the default database. Set by the server if the default database changes, if there is no default database the value from the collation_server variable is used. This variable is dynamic, but should not be set manually, only by the server.
Command line: --collation-server=name
Default Value: latin1_swedish_ci
Description: The transaction completion type. If set to NO_CHAIN or 0 (the default), there is no effect on commits and rollbacks. If set to CHAIN or 1, a COMMIT statement is equivalent to COMMIT AND CHAIN, while a ROLLBACK is equivalent to ROLLBACK AND CHAIN, so a new transaction starts straight away with the same isolation level as transaction that's just finished. If set to RELEASE or 2, a COMMIT statement is equivalent to COMMIT RELEASE, while a ROLLBACK is equivalent to ROLLBACK RELEASE, so the server will disconnect after the transaction completes. Note that the transaction completion type only applies to explicit commits, not implicit commits.
Command line: --completion-type=name
Valid Values: 0, 1, 2, NO_CHAIN, CHAIN, RELEASE
Description: If set to AUTO or 1, the default, MariaDB allows concurrent INSERTs and SELECTs for MyISAM tables with no free blocks in the data (deleted rows in the middle). If set to NEVER or 0, concurrent inserts are disabled. If set to ALWAYS or 2, concurrent inserts are permitted for all MyISAM tables, even those with holes, in which case new rows are added at the end of a table if the table is being used by another thread. If the --skip-new option is used when starting the server, concurrent_insert is set to NEVER. Changing the variable only affects new opened tables. Use FLUSH TABLES If you want it to also affect cached tables. See Concurrent Inserts for more.
Command line: --concurrent-insert[=value]
Valid Values: 0, 1, 2, AUTO, NEVER, ALWAYS
Description: Time in seconds that the server waits for a connect packet before returning a 'Bad handshake'. Increasing may help if clients regularly encounter 'Lost connection to MySQL server at 'X', system error: error_number' type-errors.
Command line: --connect-timeout=#
Description: Write a core-file on crashes. The file name and location are system dependent. On Linux it is usually called core.${PID}, and it is usually written to the data directory. However, this can be changed.
Note that the option accepts no arguments; specifying --core-file sets the value to ON. It cannot be disabled in the case of Windows >= MariaDB 10.4.3.
Command line: --core-file
Description: Directory where the data is stored.
Command line: --datadir=path or -h path
Description: Available in debug builds only (built with -DWITH_DEBUG=1). Used in debugging through the DBUG library to write to a trace file. Just using --debug will write a trace of what mariadbd is doing to the default trace file.
Command line: -#, --debug[=debug_options]
Default Value:
= MariaDB 10.5:
d:t:i:o,/tmp/mariadbd.trace(Unix) ord:t:i:O,\mariadbd.trace(Windows)
Debug Options: See the option flags on the mysql_debug page
Description: Disable system thread alarm calls. Disabling it may be useful in debugging or testing, never do it in production.
Command line: --debug-no-thead-alarm=#
Description: Used in debugging to show the interface to the Debug Sync facility. MariaDB needs to be configured with -DENABLE_DEBUG_SYNC=1 for this variable to be available.
Default Value: OFF or ON - current signal name
default_password_lifetime
Description: This defines the global password expiration policy. 0 means automatic password expiration is disabled. If the value is a positive integer N, the passwords must be changed every N days. This behavior can be overridden using the password expiration options in ALTER USER.
Command line: --default-password-lifetime=#
Description: Introduced to address remaining incompatibilities between PCRE and the old regex library. Accepts a comma-separated list of zero or more of the following values:
. matches anything including NL
Allow duplicate names for subpatterns
Ignore white space and comments
extra features (e.g. error on unknown escape character)
^ and $ match newlines within data
Invert greediness of quantifiers
Command line: --default-regex-flags=value
Valid Values: DOTALL, DUPNAMES, EXTENDED, EXTRA, MULTILINE, UNGREEDY
Description: The default storage engine. The default storage engine must be enabled at server startup or the server won't start.
Command line: --default-storage-engine=name
Command line: --default-table-type=name
default_tmp_storage_engine
Command line: --default-tmp-storage-engine=name
Description: Default mode for the WEEK() function. See that page for details on the different modes
Command line: --default-week-format=#
Description: Specifies how MyISAM tables handles CREATE TABLE DELAY_KEY_WRITE. If set to ON, the default, any DELAY KEY WRITEs are honored. The key buffer is then flushed only when the table closes, speeding up writes. MyISAM tables should be automatically checked upon startup in this case, and --external locking should not be used, as it can lead to index corruption. If set to OFF, DELAY KEY WRITEs are ignored, while if set to ALL, all new opened tables are treated as if created with DELAY KEY WRITEs enabled.
Command line: --delay-key-write[=name]
Valid Values: ON, OFF, ALL
Description: After this many rows have been inserted with INSERT DELAYED, the handler will check for and execute any waiting SELECT statements.
Command line: --delayed-insert-limit=#
Description: Time in seconds that the INSERT DELAYED handler will wait for INSERTs before terminating.
Command line: --delayed-insert-timeout=#
Description: Number of rows, per table, that can be queued when performing INSERT DELAYED statements. If the queue becomes full, clients attempting to perform INSERT DELAYED's will wait until the queue has room available again.
Command line: --delayed-queue-size=#
disconnect_on_expired_password
Description: When a user password has expired (see User Password Expiry), this variable controls how the server handles clients that are not aware of the sandbox mode. If enabled, the client is not permitted to connect, otherwise the server puts the client in a sandbox mode.
Command line: --disconnect-on-expired-password[={0|1}]
Description: The precision of the result of the decimal division will be the larger than the precision of the dividend by that number. By default it's 4, so SELECT 2/15 would return 0.1333 and SELECT 2.0/15 would return 0.13333. After setting div_precision_increment to 6, for example, the same operation would return 0.133333 and 0.1333333 respectively.
From MariaDB 10.1.46, MariaDB 10.2.33, MariaDB 10.3.24, MariaDB 10.4.14 and MariaDB 10.5.5, div_precision_increment is taken into account in intermediate calculations. Previous versions did not, and the results were dependent on the optimizer, and therefore unpredictable.
In MariaDB 10.1.46, MariaDB 10.1.47, MariaDB 10.2.33, MariaDB 10.2.34, MariaDB 10.2.35, MariaDB 10.3.24, MariaDB 10.3.25, MariaDB 10.4.14, MariaDB 10.4.15, MariaDB 10.5.5 and MariaDB 10.5.6 only, the fix truncated decimal values after every division, resulting in lower precision in some cases for those versions only.
From MariaDB 10.1.48, MariaDB 10.2.35, MariaDB 10.3.26, MariaDB 10.4.16 and MariaDB 10.5.7, a different fix was implemented. Instead of truncating decimal values after every division, they are instead truncated for comparison purposes only.
For example
Versions other than MariaDB 10.1.46, MariaDB 10.1.47, MariaDB 10.2.33, MariaDB 10.2.34, MariaDB 10.2.35, MariaDB 10.3.24, MariaDB 10.3.25, MariaDB 10.4.14, MariaDB 10.4.15, MariaDB 10.5.5 and MariaDB 10.5.6:
SELECT (55/23244*1000);
+-----------------+
| (55/23244*1000) |
+-----------------+
| 2.3662 |
+-----------------+MariaDB 10.1.46, MariaDB 10.1.47, MariaDB 10.2.33, MariaDB 10.2.34, MariaDB 10.2.35, MariaDB 10.3.24, MariaDB 10.3.25, MariaDB 10.4.14, MariaDB 10.4.15, MariaDB 10.5.5 and MariaDB 10.5.6 only:
SELECT (55/23244*1000);
+-----------------+
| (55/23244*1000) |
+-----------------+
| 2.4000 |
+-----------------+This is because the intermediate result, SELECT 55/23244 takes into account div_precision_increment and results were truncated after every division in those versions only.
Command line: --div-precision-increment=#
Command line: --encrypt-tmp-disk-tables[={0|1}]
Description: Enables automatic encryption of temporary files, such as those created for filesort operations, binary log file caches, etc. See Data at Rest Encryption.
Command line: --encrypt-tmp-files[={0|1}]
Command line: --encryption-algorithm=value
Valid Values: none, aes_ecb, aes_cbc, aes_ctr
Description: Force the use of a particular storage engine for new tables. Used to avoid unwanted creation of tables using another engine. For example, setting to InnoDB will prevent any MyISAM tables from being created. If another engine is specified in a CREATE TABLE statement, the outcome depends on whether the NO_ENGINE_SUBSTITUTION SQL_MODE has been set or not. If set, the query will fail, while if not set, a warning will be returned and the table created according to the engine specified by this variable. The variable has a session scope, but is only modifiable by a user with the SUPER privilege.
engine_condition_pushdown
Description: Deprecated in MariaDB 5.5 and removed and replaced by the optimizer_switch engine_condition_pushdown={on|off} flag in MariaDB 10.0.. Specifies whether the engine condition pushdown optimization is enabled. Since MariaDB 10.1.1, engine condition pushdown is enabled for all engines that support it.
Command line: --engine-condition-pushdown
eq_range_index_dive_limit
Description: Limit used for speeding up queries listed by long nested INs. The optimizer will use existing index statistics instead of doing index dives for equality ranges if the number of equality ranges for the index is larger than or equal to this number. If set to 0 (unlimited), index dives are always used.
Command line: --eq-range-index-dive-limit=#
Description: Read-only variable denoting the number of errors from the most recent statement in the current session that generated errors. See SHOW_ERRORS().
Description: Status of the Event Scheduler. Can be set to ON or OFF, while DISABLED means it cannot be set at runtime. Setting the variable will cause a load of events if they were not loaded at startup.
Command line: --event-scheduler[=value]
Valid Values: ON (or 1), OFF (or 0), DISABLED
Description: Number of rows to be examined for a query to be considered expensive, that is, maximum number of rows a subquery may examine in order to be executed during optimization and used for constant optimization.
Command line: --expensive-subquery-limit=#
explicit_defaults_for_timestamp
Description: This option causes CREATE TABLE to create all TIMESTAMP columns as NULL with the DEFAULT NULL attribute, Without this option, TIMESTAMP columns are NOT NULL and have implicit DEFAULT clauses.
Command line: --explicit-defaults-for-timestamp=[={0|1}]
Description: Usually, MariaDB writes changes to disk after each SQL statement, and the operating system handles synchronizing (flushing) it to disk. If set to ON, the server will synchronize all changes to disk after each statement.
Description: Interval in seconds that tables are closed to synchronize (flush) data to disk and free up resources. If set to 0, the default, there is no automatic synchronizing tables and closing of tables. This option should not be necessary on systems with sufficient resources.
Command line: --flush_time=#
Description: If set to 1 (the default) foreign key constraints (including ON UPDATE and ON DELETE behavior) InnoDB tables are checked, while if set to 0, they are not checked. 0 is not recommended for normal use, though it can be useful in situations where you know the data is consistent, but want to reload data in a different order from that specified by parent/child relationships. Setting this variable to 1 does not retrospectively check for inconsistencies introduced while set to 0.
Description: List of operators supported by an IN BOOLEAN MODE full-text search. If you wish to change, note that each character must be ASCII and non-alphanumeric, the full string must be 14 characters and the first or second character must be a space (marking the behavior by default). Positions 10, 13 and 14 are reserved for future extensions. Also, no duplicates are permitted except for the phrase quoting characters in positions 11 and 12, which may be the same.
Command line: --ft-boolean-syntax=name
Default Value: + -><()*:""&|
Description: Maximum length for a word to be included in the MyISAM full-text index. If this variable is changed, the full-text index must be rebuilt in order for the new value to take effect. The quickest way to do this is by issuing a REPAIR TABLE table_name QUICK statement. See innodb_ft_max_token_size for the InnoDB equivalent.
Command line: --ft-max-word-len=#
Description: Minimum length for a word to be included in the MyISAM full-text index. If this variable is changed, the full-text index must be rebuilt in order for the new value to take effect. The quickest way to do this is by issuing a REPAIR TABLE table_name QUICK statement. See innodb_ft_min_token_size for the InnoDB equivalent.
Command line: --ft-min-word-len=#
Description: For full-text searches, denotes the numer of top matches when using WITH QUERY EXPANSION.
Command line: --ft-query-expansion-limit=#
Description: File containing a list of stopwords for use in MyISAM full-text searches. Unless an absolute path is specified the file will be looked for in the data directory. The file is not parsed for comments, so all words found become stopwords. By default, a built-in list of words (built from storage/myisam/ft_static.c file) is used. Stopwords can be disabled by setting this variable to '' (an empty string). If this variable is changed, the full-text index must be rebuilt. The quickest way to do this is by issuing a REPAIR TABLE table_name QUICK statement. See innodb_ft_server_stopword_table for the InnoDB equivalent.
Command line: --ft-stopword-file=file_name
Default Value: (built-in)
Description: If set to 0, the default unless the --general-log option is used, the general query log is disabled, while if set to 1, the general query log is enabled. See log_output for how log files are written. If that variable is set to NONE, no logs will be written even if general_query_log is set to 1.
Command line: --general-log
Description: Name of the general query log file. If this is not specified, the name is taken from the log-basename setting or from your system hostname with .log as a suffix. If --log-basename is also set, general_log_file should be placed after in the config files. Later settings override earlier settings, so log-basename will override any earlier log file name settings.
Command line: --general-log-file=file_name
Default Value: host_name.log
Command line: --group-concat-max-len=#
.
Description: If the zlib compression library is accessible to the server, this will be set to YES, otherwise it will be NO. The COMPRESS() and UNCOMPRESS() functions will only be available if set to YES.
Description: If the crypt() system call is available this variable will be set to YES, otherwise it will be set to NO. If set to NO, the ENCRYPT() function cannot be used.
Description: If the server supports dynamic loading of plugins, will be set to YES, otherwise will be set to NO.
Description: If the server supports spatial data types, will be set to YES, otherwise will be set to NO.
Description: If the server supports NDBCluster.
Description: If the server supports partitioning, will be set to YES, unless the --skip-partition option is used, in which case will be set to DISABLED. Will be set to NO otherwise. Removed in MariaDB 10.0 - SHOW PLUGINS should be used instead.
Description: If the server supports the query cache, will be set to YES, otherwise will be set to NO.
Description: If RTREE indexes (used for spatial indexes) are available, will be set to YES, otherwise will be set to NO.
Description: This system variable can be used to determine whether the server supports symbolic links (note that it has no meaning on Windows).
If symbolic links are supported, then the value will be YES.
If symbolic links are not supported, then the value will be NO.
If symbolic links are disabled with the --symbolic-links option and the skip option prefix (i.e. --skip-symbolic-links), then the value will be DISABLED.
Command line: --histogram-size=#
Description: Specifies the type of histograms created by ANALYZE..
SINGLE_PREC_HB - single precision height-balanced.
DOUBLE_PREC_HB - double precision height-balanced.
JSON_HB - JSON height-balanced histograms (from MariaDB 10.8)
Command line: --histogram-type=value
Description: Number of host names that will be cached to avoid resolving. Setting to 0 disables the cache. Changing the value while the server is running causes an implicit FLUSH HOSTS, clearing the host cache and truncating the performance_schema.host_cache table. If you are connecting from a lot of different machines you should consider increasing.
Command line: --host-cache-size=#.
Description: When the server starts, this variable is set to the server host name.
idle_readonly_transaction_timeout
idle_write_transaction_timeout
Description: Tells the server that this directory can never be a database. That means two things - firstly it is ignored by the SHOW DATABASES command and INFORMATION_SCHEMA tables. And secondly, USE, CREATE DATABASE and SELECT statements will return an error if the database from the ignored list specified. Use this option several times if you need to ignore more than one directory. To make the list empty set the void value to the option as --ignore-db-dir=. If the option or configuration is specified multiple times, viewing this value will list the ignore directories separated by commas.
Command line: --ignore-db-dirs=dir.
in_predicate_conversion_threshold
Command line: --in-predicate-conversion-threshold=#
Description: Session-only and read-only variable that is set to 1 if a transaction is in progress, 0 if not.
Description: String containing one or more SQL statements, separated by semicolons, that will be executed by the server for each client connecting. If there's a syntax error in the one of the statements, the client will fail to connect. For this reason, the statements are not executed for users with the SUPER privilege or, from MariaDB 10.5.2, the CONNECTION ADMIN privilege, who can then still connect and correct the error. See also init_file.
Command line: --init-connect=name
Description: Name of a file containing SQL statements that will be executed by the server on startup. Each statement should be on a new line, and end with a semicolon. See also init_connect.
Command line: init-file=file_name
Description: Value to be used for the next statement inserting a new AUTO_INCREMENT value.
Description: Time in seconds that the server waits for an interactive connection (one that connects with the mysql_real_connect() CLIENT_INTERACTIVE option) to become active before closing it. See also wait_timeout.
Command line: --interactive-timeout=#
Range: (Windows): 1 to 2147483
Range: (Other): 1 to 31536000
Description: Minimum size in bytes of the buffer used for queries that cannot use an index, and instead perform a full table scan. Increase to get faster full joins when adding indexes is not possible, although be aware of memory issues, since joins will always allocate the minimum size. Best left low globally and set high in sessions that require large full joins. In 64-bit platforms, Windows truncates values above 4GB to 4GB with a warning.
Command line: --join-buffer-size=#
Default Value: 262144 (256kB)
Range (non-Windows): 128 to 18446744073709547520
Range (Windows): 8228 to 18446744073709547520
Description: Maximum size in bytes of the query buffer, By default 102412810.
Command line: --join-buffer-space-limit=#
Range: 2048 to 18446744073709551615
Description: Controls which of the eight block-based algorithms can be used for join operations.
1 – flat (Block Nested Loop) BNL
3 – flat Block Nested Loop Hash (BNLH)
5 – flat Batch Key Access (BKA)
7 – flat Batch Key Access Hash (BKAH)
Command line: --join-cache-level=#
Description: If a MyISAM table is created with no DATA DIRECTORY option, the .MYD file is stored in the database directory. When set to 0, the default, if MariaDB finds another .MYD file in the database directory it will overwrite it. Setting this variable to 1 means that MariaDB will return an error instead, just as it usually does in the same situation outside of the database directory. The same applies for .MYI files and no INDEX DIRECTORY option. Deprecated in MariaDB 10.8.0.
Command line: --keep-files-on-create=#
Description: ON if the server if was compiled with large file support or not, else OFF
Description: Indicates the size of memory page if large page support (Linux only) is enabled. The page size is determined from the Hugepagesize setting in /proc/meminfo. See large_pages. Deprecated and unused in MariaDB 10.5.3 since multiple page size support was added.
Default Value: Autosized (see description)
Description: Indicates whether large page support (prior to MariaDB 10.5, Linux only, by now supported Windows and BSD distros, also called huge pages) is used. This is set with --large-pages or disabled with --skip-large-pages. Large pages are used for the innodb buffer pool and for online DDL (of size 3* innodb_sort_buffer_size (or 6 when encryption is used)). To use large pages, the Linux sysctl variable kernel.shmmax must be large than the llocation. Also the sysctl variable vm.nr_hugepages multipled by large-page) must be larger than the usage. The ulimit for locked memory must be sufficient to cover the amount used (ulimit -l and equalivent in /etc/security/limits.conf / or in systemd LimitMEMLOCK). If these operating system controls or insufficient free huge pages are available, the allocation of large pages will fall back to conventional memory allocation and a warning will appear in the logs. Only allocations of the default Hugepagesize currently occur (see /proc/meminfo).
Command line: --large-pages, --skip-large-pages
Description: Contains the same value as that returned by LAST_INSERT_ID(). Note that setting this variable doen't update the value returned by the underlying function.
Description: This system variable can be specified as a locale name. The language of the associated locale will be used for error messages. See Server Locales for a list of supported locales and their associated languages.
This system variable is set to en_US by default, which means that error messages are in English by default.
If this system variable is set to a valid locale name, but the server can't find an error message file for the language associated with the locale, then the default language will be used instead.
Command line: --lc-messages=name
Description: This system variable can be specified either as the path to the directory storing the server's error message files or as the path to the directory storing the specific language's error message file. See Server Locales for a list of available locales and their related languages.
The server initially tries to interpret the value of this system variable as a path to the directory storing the server's error message files. Therefore, it constructs the path to the language's error message file by concatenating the value of this system variable with the language name of the locale specified by the lc_messages system variable .
If the server does not find the error message file for the language, then it tries to interpret the value of this system variable as a direct path to the directory storing the specific language's error message file.
Command line: --lc-messages-dir=path
Data Type: directory name
Description: The locale that determines the language used for the date and time functions DAYNAME(), MONTHNAME() and DATE_FORMAT() . Locale names are language and region subtags, for example 'en_ZA' (English - South Africa) or 'es_US: Spanish - United States'. The default is always 'en-US' regardless of the system's locale setting. See server locale for a full list of supported locales.
Command line: --lc-time-names=name
legacy_xa_rollback_at_disconnect
Description: If a user session disconnects after putting a transaction into the XA PREPARE state, roll back the transaction. Can be used for backwards compatibility to enable this pre-10.5 behavior for applications that expect it. Note that this violates the XA Specification and should not be used for new code.
Description: Server license, for example GPL.
Description: If set to 1, LOCAL is supported for LOAD DATA INFILE statements. If set to 0, usually for security reasons, attempts to perform a LOAD DATA LOCAL will fail with an error message.
Command line: --local-infile=#
Command line: --lock-wait-timeout=#
Description: Indicates whether --memlock was used to lock mariadbd in memory.
Command line: -l [filename] or --log[=filename]
Description: If set, the specified type of statements (slave and/or stored procedure statements) will not be logged to the general log. Multiple values are comma-separated, without spaces.
Command line: --log-disabled_statements=value
Valid Values: slave and/or sp, or empty string for none
Description: Specifies the name of the error log. If --console is specified later in the configuration (Windows only) or this option isn't specified, errors will be logged to stderr. If no name is provided, errors will still be logged to hostname.err in the datadir directory by default. If a configuration file sets --log-error, one can reset it with --skip-log-error (useful to override a system wide configuration file). MariaDB always writes its error log, but the destination is configurable. See error log for details. Note that if --log-basename is also set, log_error should be placed after in the config files. Later settings override earlier settings, so log-basename will override any earlier log file name settings.
Command line: --log-error[=name], --skip-log-error
Default Value: (empty string)
Command line: --log-output=name
Valid Values: TABLE, FILE or NONE
log_queries_not_using_indexes
Description: Queries that don't use an index, or that perform a full index scan where the index doesn't limit the number of rows, will be logged to the slow query log (regardless of time taken). The slow query log needs to be enabled for this to have an effect. Mapped to log_slow_filter='not_using_index' from MariaDB 10.3.1.
Command line: --log-queries-not-using-indexes
log_slow_admin_statements
Command line: --log-slow-admin-statements
log_slow_disabled_statements
Command line: --log-slow-disabled_statements=value
Valid Vales: admin, call, slave and/or sp
Description: Comma-delimited string (without spaces) containing one or more settings for filtering what is logged to the slow query log. If a query matches one of the types listed in the filter, and takes longer than long_query_time, it will be logged(except for 'not_using_index' which is always logged if enabled, regardless of the time). Sets log-slow-admin-statements to ON. See also log_slow_disabled_statements.
filesort logs queries that use a filesort.
filesort_on_disk logs queries that perform a filesort on disk.
full_join logs queries that perform a join without indexes.
full_scan logs queries that perform full table scans.
query_cache log queries that are resolved by the query cache.
query_cache_miss logs queries that are not found in the query cache.
tmp_table logs queries that create an implicit temporary table.
tmp_table_on_disk logs queries that create a temporary table on disk.
Command line: log-slow-filter=value1[,value2...]
Default Value:
admin, filesort, filesort_on_disk, filesort_priority_queue, full_join, full_scan, query_cache, query_cache_miss, tmp_table, tmp_table_on_disk
Valid Values:
admin, filesort, filesort_on_disk, filesort_priority_queue, full_join, full_scan, not_using_index, query_cache, query_cache_miss, tmp_table, tmp_table_on_disk
Description: Max numbers of warnings printed to slow query log per statement
Command line: log-slow-max-warnings=#
log_slow_min_examined_row_limit
Description: Don't write queries to slow query log that examine fewer rows than the set value. If set to 0, the default, no row limit is used. min_examined_row_limit is an alias. From MariaDB 11.7, queries slower than log_slow_always_query_time will always be logged.
Command line: --log-slow-min-examined-row-limit=#
Command line: --log-slow-queries[=name]
Description: If set to 0, the default unless the --slow-query-log option is used, the slow query log is disabled, while if set to 1 (both global and session variables), the slow query log is enabled. Named slow_query_log before MariaDB 10.11.0, which is now an alias.
Command line: --slow-query-log
See also: See log_output to see how log files are written. If that variable is set to NONE, no logs will be written even if log_slow_query is set to 1.
Description: Name of the slow query log file. Before MariaDB 10.11, was named slow_query_log_file. This was named log_slow_query_file_name in the MariaDB 10.11.0 preview release. If --log-basename is also set, log_slow_query_file should be placed after in the config files. Later settings override earlier settings, so log-basename will override any earlier log file name settings.
Command line: --log-slow-query-file=file_name
Default Value: host_name-slow.log
Command line: --log-slow-query-time=#
Command line: log-slow-rate-limit=#
Description: Controls information to be added to the slow query log. Options are added in a comma-delimited string. See also Slow Query Log Extended Statistics. log_slow_verbosity is not supported when log_output='TABLE'.
query_plan logs query execution plan information
warnings Print all errors, warnings and notes for the statement to the slow query log. (from MariaDB 10.6.16).
full Enables all above options.
Command line: log-slow-verbosity=value1[,value2...]
Description: Defines the size in bytes of the memory-mapped file-based transaction coordinator log, which is only used if the binary log is disabled. If you have two or more XA-capable storage engines enabled, then a transaction coordinator log must be available. This size is defined in multiples of 4096. See Transaction Coordinator Log for more information. Also see the --log-tc server option and the --tc-heuristic-recover option.
Command line: log-tc-size=#
Range: 12288 to 18446744073709551615
Description: Determines which additional warnings are logged. Setting to 0 disables additional warning logging. Note that this does not prevent all warnings, there is a core set of warnings that will always be written to the error log. The additional warnings are as follows:
Failed setrlimit() and mlockall()
Wrong values of lower_case_table_names and stack_size
Wrong values for command line options
Start log position and some master information when starting slaves
Disabled plugins that one tried to enable or use.
UDF files that didn't include the required init functions.
Connections aborted or closed due to errors or timeouts.
Either the default master.info file or the file that is configured by the master_info_file option.
Either the default relay-log.info file or the file that is configured by the relay_log_info_file system variable.
All errors and warnings during MyISAM repair and auto recover.
Information about old-style language options.
Connections aborted due to "Too many connections" errors.
Connections closed normally without authentication.
Connections aborted due to KILL.
Connections closed due to released connections, such as when completion_type is set to RELEASE.
Could not read packet: (a lot more information)
All read/write errors for a connection are logged to the error log.
Information about initializing plugins.
Command line: -W [level] or --log-warnings[=level]
Command line: --long-query-time=#
Description: If set to 1 (0 is the default), for storage engines that use only table-level locking (Aria, MyISAM, MEMORY and MERGE), all INSERTs, UPDATEs, DELETEs and LOCK TABLE WRITEs will wait until there are no more SELECTs or LOCK TABLE READs pending on the relevant tables. Set this to 1 if reads are prioritized over writes.
Command line: --low-priority-updates
Description: Read-only variable describing whether the file system is case-sensitive. If set to OFF, file names are case-sensitive. If set to ON, they are not case-sensitive.
Description: If set to 0 (the default on Unix-based systems), table names and aliases and database names are compared in a case-sensitive manner. If set to 1 (the default on Windows), names are stored in lowercase and not compared in a case-sensitive manner. If set to 2 (the default on Mac OS X), names are stored as declared, but compared in lowercase. This system variable's value cannot be changed after the datadir has been initialized. lower_case_table_names is set when a MariaDB instance starts, and it remains constant afterwards.
Command line: --lower-case-table-names[=#]
Default Value: 0 (Unix), 1 (Windows), 2 (Mac OS X)
Description: Maximum size in bytes of a packet or a generated/intermediate string. The packet message buffer is initialized with the value from net_buffer_length, but can grow up to max_allowed_packet bytes. Set as large as the largest BLOB, in multiples of 1024. If this value is changed, it should be changed on the client side as well. See slave_max_allowed_packet for a specific limit for replication purposes.
Command line: --max-allowed-packet=#
Dynamic: Yes (Global), No (Session)
Default Value:
1073741824 (1GB) (client-side)
Range: 1024 to 1073741824
Description: Limit to the number of successive failed connects from a host before the host is blocked from making further connections. The count for a host is reset to zero if they successfully connect. To unblock, flush the host cache with a FLUSH HOSTS statement or mariadb-admin flush-hosts. The performance_schema.host_cache table contains the status of the current hosts.
Command line: --max-connect-errors=#
Description: The maximum number of simultaneous client connections. See also Handling Too Many Connections. Note that this value affects the number of file descriptors required on the operating system. Minimum was changed from 1 to 10 to avoid possible unexpected results for the user (MDEV-18252 ). Note that MariaDB always has one reserved connection for a SUPER (or CONNECTION ADMIN user). Additionally it can listen on a separate port, so will be available even when the max_connections limit is reached.
Command line: --max-connections=#
Description: Limits to the number of INSERT DELAYED threads. Once this limit is reached, the insert is handled as if there was no DELAYED attribute. If set to 0, DELAYED is ignored entirely. The session value can only be set to 0 or to the same as the global value.
Command line: --max-delayed-threads=#
Description: Maximum length considered for computing a statement digest, such as used by the Performance Schema and query rewrite plugins. Statements that differ after this many bytes produce the same digest, and are aggregated for statistics purposes. The variable is allocated per session. Increasing will allow longer statements to be distinguished from each other, but increase memory use, while decreasing will reduce memory use, but more statements may become indistinguishable.
Command line: --max-digest-length=#
Command line: --max-error-count=#
Description: Maximum size in bytes for user-created MEMORY tables. Setting the variable while the server is active has no effect on existing tables unless they are recreated or altered. The smaller of max_heap_table_size and tmp_table_size also limits internal in-memory tables. When the maximum size is reached, any further attempts to insert data will receive a "table ... is full" error. Temporary tables created with CREATE TEMPORARY will not be converted to Aria, as occurs with internal temporary tables, but will also receive a table full error.
Command line: --max-heap-table-size=#
Range : 16384 to 4294966272
max_insert_delayed_threads
Description: Statements will not be performed if they are likely to need to examine more than this number of rows, row combinations or do more disk seeks. Can prevent poorly-formatted queries from taking server resources. Changing this value to anything other the default will reset sql_big_selects to 0. If sql_big_selects is set again, max_join_size will be ignored. This limit is also ignored if the query result is sitting in the query cache. Previously named sql_max_join_size, which is still a synonym.
Command line: --max-join-size=#
Default Value: 18446744073709551615
Range: 1 to 18446744073709551615
Description: Used to decide which algorithm to choose when sorting rows. If the total size of the column data, not including columns that are part of the sort, is less than max_length_for_sort_data, then we add these to the sort key. This can speed up the sort as we don't have to re-read the same row again later. Setting the value too high can slow things down as there will be a higher disk activity for doing the sort.
Command line: --max-length-for-sort-data=#
Command line: --max-long-data-size=#
Default Value: 16777216 (16M)
Range: 1024 to 4294967295
Description: The maximum number of open cursors allowed per session.
Command line: --max-open-cursors=#
Description: The maximum permitted number of failed connection attempts due to an invalid password before a user is blocked from further connections. FLUSH_PRIVILEGES will permit the user to connect again. This limit is not applicable for users with the SUPER privilege or, from MariaDB 10.5.2, the CONNECTION ADMIN privilege, with a hostname of localhost, 127.0.0.1 or ::1. See also the Information Schema USERS table.
Command line: --max-password-errors=#
Default Value: 4294967295
Description: Maximum number of prepared statements on the server. Can help prevent certain forms of denial-of-service attacks. If set to 0, no prepared statements are permitted on the server.
Command line: --max-prepared-stmt-count=#
Description: Maximum number of iterations when executing recursive queries, used to prevent infinite loops in recursive CTEs.
Command line: --max-recursive-iterations=#
Description: The maximum size of the container of a rowid filter.
Command line: --max-rowid-filter-size=#
Range: 1024 to 18446744073709551615
Description: The optimizer assumes that the number specified here is the most key seeks required when searching with an index, regardless of the actual index cardinality. If this value is set lower than its default and maximum, indexes will tend to be preferred over table scans.
Command line: --max-seeks-for-key=#
Default Value: 4294967295
Description: Amount of memory a single user session is allowed to allocate. This limits the value of the session variable Memory_used.
Command line: --max-session-mem-used=#
Default Value: 9223372036854775807 (8192 PB)
Range: 8192 to 18446744073709551615
Description: Maximum size in bytes used for sorting data values - anything exceeding this is ignored. The server uses only the first max_sort_length bytes of each value and ignores the rest. Increasing this may require sort_buffer_size to be increased (especially if ER_OUT_OF_SORTMEMORY errors start appearing). From MariaDB 11.7, a warning is generated when max_sort_length is exceeded.
Command line: --max-sort-length=#
Description: Permitted number of recursive calls for a stored procedure. 0, the default, no recursion is permitted. Increasing this value increases the thread stack requirements, so you may need to increase thread_stack as well. This limit doesn't apply to stored functions.
Command line: --max-sp-recursion-depth[=#]
Command line: --max-statement-time[=#]
Description: Maximum simultaneous connections permitted for each user account. When set to 0, there is no per user limit. Setting it to -1 stops users without the SUPER privilege or, from MariaDB 10.5.2, the CONNECTION ADMIN privilege, from connecting to the server. The session variable is always read-only and only privileged users can modify user limits. The session variable defaults to the global max_user_connections variable, unless the user's specific MAX_USER_CONNECTIONS resource option is non-zero. When both global variable and the user resource option are set, the user's MAX_USER_CONNECTIONS is used. Note: This variable does not affect users with the SUPER privilege or, from MariaDB 10.5.2, the CONNECTION ADMIN privilege.
Command line: --max-user-connections=#
Dynamic: Yes, (except when globally set to 0 or -1)
Description: Read lock requests will be permitted for processing after this many write locks. Applies only to storage engines that use table level locks (thr_lock), so no effect with InnoDB or Archive.
Command line: --max-write-lock-count=#
Default Value: 4294967295
metadata_locks_cache_size
Description: Unused since 10.1.4
Command line: --metadata-locks-cache-size=#
metadata_locks_hash_instances
Description: Unused since 10.1.4
Command line: --metadata-locks-hash-instances=#
Description: Number of fast lanes to create for metadata locks. Can be used to improve DML scalability by eliminating MDL_lock::rwlock load. Use 1 to disable MDL fast lanes. Supported MDL namespaces: BACKUP.
Command line: --metadata-locks-instances=#
Command line: --min-examined-row-limit=#
Command line: --mrr-buffer-size=#
Command line: --multi-range-count=#
Description: If set (the default), MariaDB uses the MySQL 5.6 low level formats for TIME, DATETIME and TIMESTAMP instead of the MariaDB 5.3 version. The version MySQL introduced in 5.6 requires more storage, but potentially allows negative dates and has some advantages in replication. There should be no reason to revert to the old MariaDB 5.3 microsecond format. See also MDEV-10723 .
Command line: --mysql56-temporal-format
Description: On Windows systems, determines whether connections over named pipes are permitted.
Command line: --named-pipe
Description: The starting size, in bytes, for the connection and thread buffers for each client thread. The size can grow to max_allowed_packet. This variable's session value is read-only. Can be set to the expected length of client statements if memory is a limitation.
Command line: --net-buffer-length=#
Command line: --net-read-timeout=#
Description: Permit this many retries before aborting when attempting to read or write on a communication port. On FreeBSD systems should be set higher as threads are sent internal interrupts..
Command line: --net-retry-count=#
Command line: --net-write-timeout=#
Description: Verbosity level for note-warnings given to the user. Options are added in a comma-delimited string, except for all, which sets all options. Be aware that if the old sql_notes variable is 0, one will not get any notes. Setting note_verbosity to "" is the recommended way to disable notes.
unusable_keys Give warnings for unusable keys for SELECT, DELETE and UPDATE.
explain Give warnings for unusable keys for EXPLAIN.
all Enables all above options. This has to be given alone.
Command line: note-verbosity=value1[,value2...]
Default Value: basic,explain
Valid Values: basic,explain,unusable_keys or all.
Description: Disabled by default, enabling it reverts index hints to those used before MySQL 5.1.17. Enabling may lead to replication errors. Deprecated and replaced by old_mode from MariaDB 10.9.
Description: From MariaDB 10.3.7, an alias for alter_algorithm. Prior to that, if set to 1 (0 is default), MariaDB reverts to the non-optimized, pre-MySQL 5.1, method of processing ALTER TABLE statements. A temporary table is created, the data is copied over, and then the temporary table is renamed to the original.
Command line: --old-alter-table
Description: Used for getting MariaDB to emulate behavior from an old version of MySQL or MariaDB. See OLD Mode. Fully replaces the old variable from MariaDB 10.9. Non-default OLD_MODE options are by design deprecated and will eventually be removed.
Valid Values: See OLD Mode for the full list.
Description: If set to 1 (0 is default), MariaDB reverts to using the mysql_old_password authentication plugin by default for newly created users and passwords, instead of the mysql_native_password authentication plugin.
Description: The number of file descriptors available to MariaDB. If you are getting the Too many open files error, then you should increase this limit. If set to 0, then MariaDB will calculate a limit based on the following:
MAX(max_connections*5, max_connections +table_open_cache*2)
MariaDB sets the limit with setrlimit . MariaDB cannot set this to exceed the hard limit imposed by the operating system. Therefore, you may also need to change the hard limit. There are a few ways to do so.
Command line: --open-files-limit=count
Default Value: Autosized (see description)
optimizer_extra_pruning_depth
Description:If the optimizer needs to enumerate a join prefix of this size or larger, then it will try aggressively prune away the search space.
Command line: --optimizer-extra-pruning-depth[=#]
optimizer_join_limit_pref_ratio
Command line: --optimizer-join-limit-pref-ratio[=#]
Default Value: 0 (Disable)
optimizer_max_sel_arg_weight
Description: This is an actively enforced maximum effective SEL_ARG tree weight limit. A SEL_ARG weight is the number of effective "ranges" hanging off this root (that is, merged tree elements are "unmerged" to count the weight). During range analysis, looking for possible index merges, SEL_ARG graphs related to key ranges in query conditions are being processed. Graphs exceeding this limit will stop keys being 'and'ed and 'or'ed together to form a new larger SEL_ARG graph. After each 'and' or 'or' process, this maximum weight limit is enforced. It enforces this limit by pruning the key part being used. This key part pruning can be used to limit/disable index merge SEL_ARG graph construction on overly long query conditions.
Command line: --optimizer-max-sel-arg-weight=#
Range: 0 to 18446744073709551615
Description: The maximum number of SEL_ARG objects created when optimizing a range. If more objects would be needed, range scans will not be used by the optimizer.
Command line: --optimizer-max-sel-args=#
Description:Controls the heuristic(s) applied during query optimization to prune less-promising partial plans from the optimizer search space.
0: heuristics are disabled and an exhaustive search is performed
1: the optimizer will use heuristics to prune less-promising partial plans from the optimizer search space
2: tables using EQ_REF will be joined together as 'one entity' and the different combinations of these tables will not be considered (from MariaDB 10.10)
Command line: --optimizer-prune-level[=#]
Description: Maximum search depth by the query optimizer. Smaller values lead to less time spent on execution plans, but potentially less optimal results. If set to 0, MariaDB will automatically choose a reasonable value. Since the better results from more optimal planning usually offset the longer time spent on planning, this is set as high as possible by default. 63 is a valid value, but its effects (switching to the original find_best search) are deprecated.
Command line: --optimizer-search-depth[=#]
optimizer_selectivity_sampling_limit
Description: Controls number of record samples to check condition selectivity. Only used if [optimizer_use_condition_selectivity](server-system-variables.md#optimizer_use_condition_selectivity) > 4.
Command line: optimizer-selectivity-sampling-limit[=#]
Description: A series of flags for controlling the query optimizer. See Optimizer Switch for defaults, and a comparison to MySQL.
Command line: --optimizer-switch=value
Valid Values:
condition_pushdown_for_derived={on|off}
condition_pushdown_for_subquery={on|off}
condition_pushdown_from_having={on|off}
default - set all optimizations to their default values.
engine_condition_pushdown={on|off}. Deprecated in MariaDB 10.1.1 as engine condition pushdown is now automatically enabled for all engines that support it.
index_merge_intersection={on|off}
index_merge_sort_union={on|off}
index_merge_union={on|off}
orderby_uses_equalities={on|off} - if not set, the optimizer ignores equality propagation. See MDEV-8989 .
split_materialized={on|off}
Description: Controls storing of optimizer context of all tables that are referenced in a query.
Command line: --optimizer-record-context{=0|1}
Description: Controls tracing of the optimizer: optimizer_trace=option=val[,option=val...], where option is one of {enabled} and val is one of {on, off, default}
Command line: --optimizer-trace=value
Default Value: enabled=off
Valid Values: enabled={on|off|default}
optimizer_trace_max_mem_size
Description: Limits the memory used while tracing a query by specifying the maximum allowed cumulated size, in bytes, of stored optimizer traces.
Command line: --optimizer-trace-max-mem-size=#
Range: 1 to 18446744073709551615
optimizer_use_condition_selectivity
Description: Controls which statistics can be used by the optimizer when looking for the best query execution plan. In most cases, the default value, 4 will be suitable. However, if you are hitting some of the rare cases where this does not work well (see MDEV-23707 ), you can usually work around this by setting this variable to 1.
Command line: --optimizer-use-condition-selectivity=#
Description: Full path of the process ID file. If --log-basename is also set, pid_file should be placed after in the config files. Later settings override earlier settings, so log-basename will override any earlier log file name settings.
Command line: --pid-file=file_name
Description: Path to the plugin directory. For security reasons, either make sure this directory can only be read by the server, or set secure_file_priv.
Command line: --plugin-dir=path
Data Type: directory name
Default Value: BASEDIR/lib/plugin
Description: The lowest acceptable plugin maturity. MariaDB will not load plugins less mature than the specified level.
Command line: --plugin-maturity=level
Default Value: One less than the server maturity
Valid Values: unknown, experimental, alpha, beta, gamma, stable
Description: Port to listen for TCP/IP connections. If set to 0, will default to, in order of preference, my.cnf, the MYSQL_TCP_PORT environment variable, /etc/services, built-in default (3306).
Command line: --port=#, -P
Description: Size in bytes of the buffer allocated when indexes are preloaded.
Command line: --preload-buffer-size=#
Range: 1024 to 1073741824
Description: Number of statements about which profiling information is maintained. If set to 0, no profiles are stored. See SHOW PROFILES.
Command line: --profiling-history-size=#
Description: Time in seconds between sending progress reports to the client for time-consuming statements. If set to 0, progress reporting will be disabled.
Command line: --progress-report-time=#
Description: The version of the client/server protocol used by the MariaDB server.
Description: Enable proxy protocol for these source networks. The syntax is a comma separated list of IPv4 and IPv6 networks. If the network doesn't contain a mask, it is considered to be a single host. "*" represents all networks and must be the only directive on the line. String "localhost" represents non-TCP local connections (Unix domain socket, Windows named pipe or shared memory). See Proxy Protocol Support.
Command line: --proxy-protocol-networks=value
Description: Set to the proxy user account name if the current client is a proxy, else NULL.
Description: For internal use by the server.
Description: For internal use only.
Description: Size in bytes of the extra blocks allocated during query parsing and execution (after query_prealloc_size is used up).
Command line: --query-alloc-block-size=#
Range - 32 bit: 1024 to 4294967295
Range - 64 bit: 1024 to 18446744073709547520
Description: Size in bytes for which results larger than this are not stored in the query cache.
Command line: --query-cache-limit=#
Default Value: 1048576 (1MB)
Description: Minimum size in bytes of the blocks allocated for query cache results.
Command line: --query-cache-min-res-unit=#
Default Value: 4096 (4KB)
Range - 32 bit: 1024 to 4294967295
Range - 64 bit: 1024 to 18446744073709547520
Description: Size in bytes available to the query cache. About 40KB is needed for query cache structures, so setting a size lower than this will result in a warning. 0, the default before MariaDB 10.1.7, effectively disables the query cache.
Warning: Starting from MariaDB 10.1.7, query_cache_type is automatically set to ON if the server is started with the query_cache_size set to a non-zero (and non-default) value. This will happen even if query_cache_type is explicitly set to OFF in the configuration.
Command line: --query-cache-size=#
Default Value: 1M (although frequently given a default value in some setups)
Valid Values: 0 upwards in units of 1024.
query_cache_strip_comments
Description: If set to 1 (0 is default), the server will strip any comments from the query before searching to see if it exists in the query cache. Multiple space, line feeds, tab and other white space characters will also be removed.
Command line: query-cache-strip-comments
Description: If set to 0, the query cache is disabled (although a buffer of query_cache_size bytes is still allocated). If set to 1 all SELECT queries will be cached unless SQL_NO_CACHE is specified. If set to 2 (or DEMAND), only queries with the SQL CACHE clause will be cached. Note that if the server is started with the query cache disabled, it cannot be enabled at runtime.
Warning: Starting from MariaDB 10.1.7, query_cache_type is automatically set to ON if the server is started with the query_cache_size set to a non-zero (and non-default) value. This will happen even if query_cache_type is explicitly set to OFF in the configuration.
Command line: --query-cache-type=#
Valid Values: 0 or OFF, 1 or ON, 2 or DEMAND
query_cache_wlock_invalidate
Description: If set to 0, the default, results present in the query cache will be returned even if there's a write lock on the table. If set to 1, the client will first have to wait for the lock to be released.
Command line: --query-cache-wlock-invalidate
Description: Size in bytes of the persistent buffer for query parsing and execution, allocated on connect and freed on disconnect. Increasing may be useful if complex queries are being run, as this will reduce the need for more memory allocations during query operation. See also query_alloc_block_size.
Command line: --query-prealloc-size=#
Range: 1024 to 4294967295
Description: rand_seed1 and rand_seed2 facilitate replication of the RAND() function. The master passes the value of these to the slaves so that the random number generator is seeded in the same way, and generates the same value, on the slave as on the master. Until MariaDB 10.1.4, the variable value could not be viewed, with the SHOW VARIABLES output always displaying zero.
Range: 0 to 18446744073709551615
Description: Size in bytes of blocks allocated during range optimization. The unit size in 1024.
Command line: --range-alloc-block-size=#
Range - 32 bit: 4096 to 4294967295
Range - 64 bit: 4096 to 18446744073709547520
Description: Each thread performing a sequential scan (for MyISAM, Aria and MERGE tables) allocates a buffer of this size in bytes for each table scanned. Increase if you perform many sequential scans. If not in a multiple of 4KB, will be rounded down to the nearest multiple. Also used in ORDER BY's for caching indexes in a temporary file (not temporary table), for caching results of nested queries, for bulk inserts into partitions, and to determine the memory block size of MEMORY tables.
Command line: --read-buffer-size=#
Range: 8192 to 2147479552
Description: Do not allow changes to non-temporary tables. Options are: OFF — changes allowed; ON — Disallow changes for users without the READ ONLY ADMIN privilege; NO_LOCK — Additionally disallows LOCK TABLES and SELECT ... IN SHARE MODE; NO_LOCK_NO_ADMIN — Disallows also for users with READ_ONLY ADMIN privilege. Replication (slave) threads are not affected by this option.
Command line: --read-only
Valid values: OFF, ON, NO_LOCK, NO_LOCK_NO_ADMIN
Description: When set to 1 (0 is default), no updates are permitted except from users with the SUPER privilege or, from MariaDB 10.5.2, the READ ONLY ADMIN privilege, or replica servers updating from a primary. The read_only variable is useful for replica servers to ensure no updates are accidentally made outside of what are performed on the primary. Inserting rows to log tables, updates to temporary tables and OPTIMIZE TABLE or ANALYZE TABLE statements are excluded from this limitation. If read_only is set to 1, then the SET PASSWORD statement is limited only to users with the SUPER privilege (<= MariaDB 10.5.1) or READ ONLY ADMIN privilege (>= MariaDB 10.5.2). Attempting to set this variable to 1 will fail if the current session has table locks or transactions pending, while if other sessions hold table locks, the statement will wait until these locks are released before completing. While the attempt to set read_only is waiting, other requests for table locks or transactions will also wait until read_only has been set. See Read-Only Replicas for more. From MariaDB 10.5.2, the READ_ONLY ADMIN privilege will allow users granted that privilege to perform writes, even if the read_only variable is set. In earlier versions, and until MariaDB 10.11.0, users with the SUPER can perform writes while this variable is set.
Command line: --read-only
Description: Size in bytes of the buffer used when reading rows from a MyISAM table in sorted order after a key sort. Larger values improve ORDER BY performance, although rather increase the size by SESSION where the need arises to avoid excessive memory use.
Command line: --read-rnd-buffer-size=#
Range: 8200 to 2147483647
Command line: --redirect_url=val
Description: When this option is enabled, connections attempted using insecure transport will be rejected. Secure transports are SSL/TLS, Unix sockets or named pipes. Note that per-account requirements take precedence.
Command line: --require-secure-transport[={0|1}]
Command line: --rowid-merge-buff-size=#
Command line: --safe-show-database (until MySQL 4.1.1)
Command line: --secure-auth
Description: LOAD DATA, SELECT ... INTO and LOAD FILE() will only work with files in the specified path. If not set, the default, or set to empty string, the statements will work with any files that can be accessed.
Command line: --secure-file-priv=path
Description: Restricts direct setting of a session timestamp. Possible levels are:
YES - timestamp cannot deviate from the system clock. Intended to prevent tampering with system versioning history. Should not be used on replicas, as when a value based on the timestamp is inserted in statement mode, discrepancies can occur.
REPLICATION - replication thread can adjust timestamp to match the primary's
SUPER - a user with this privilege and a replication thread can adjust timestamp
NO - historical behavior, anyone can modify session timestamp
Command line: --secure-timestamp=value
Description: Automatically calculated server unique id hash. Added to the error log to allow one to verify if error reports are from the same server. UID is a base64-encoded SHA1 hash of the MAC address of one of the interfaces, and the tcp port that the server is listening on.
Description: Whether to track changes to the default schema within the current session.
Command line: --session-track-schema={0|1}
session_track_state_change
Description: Whether to track changes to the session state.
Command line: --session-track-state-change={0|1}
session_track_system_variables
Description: Comma-separated list of session system variables for which to track changes. For compatibility with MySQL defaults, this variable should be set to "autocommit, character_set_client, character_set_connection, character_set_results, time_zone". The * character tracks all session variables.
Command line: --session-track-system-variables=value
Default Value:
= MariaDB 11.3:
autocommit,character_set_client,character_set_connection,character_set_results,redirect_url,time_zone
<= MariaDB 11.2: autocommit, character_set_client, character_set_connection, character_set_results, time_zone
session_track_transaction_info
Description: Track changes to the transaction attributes. OFF to disable; STATE to track just transaction state (Is there an active transaction? Does it have any data? etc.); CHARACTERISTICS to track transaction state and report all statements needed to start a transaction with the same characteristics (isolation level, read only/read write,snapshot - but not any work done / data modified within the transaction).
Command line: --session-track-transaction-info=value
Valid Values: OFF, STATE, CHARACTERISTICS
Description: Windows only, determines whether the server permits shared memory connections. See also shared_memory_base_name.
Description: Windows only, specifies the name of the shared memory to use for shared memory connection. Mainly used when running more than one instance on the same physical machine. By default the name is MYSQL and is case sensitive. See also shared_memory.
Description: When ON, SHUTDOWN command runs with the implicit WAIT FOR ALL SLAVES option. That is, when running SHUTDOWN, before killing the binary log dump threads, the server will first kill all client threads and send all binary log events to all connected replicas.
Description: If this system variable is set, then some kinds of external table locks will be disabled for some storage engines.
If this system variable is set, then the MyISAM storage engine will not use file-based locks. Otherwise, it will use the fcntl() function with the F_SETLK option to get file-based locks on Unix, and it will use the LockFileEx() function to get file-based locks on Windows.
If this system variable is set, then the Aria storage engine will not lock a table when it decrements the table's in-file counter that keeps track of how many connections currently have the table open. See MDEV-19393 for more information.
Note that command line option name is the opposite of the variable name, and the value is the opposite too. --external-locking=1 means @@skip_external_locking=0, and vice versa.
Command line: --external-locking
Default Value: 1 (for the variable, that is 0 for the command line option)
Command line: --skip-grant-tables
Description: If set to 1 (0 is the default), only IP addresses are used for connections. Host names are not resolved. All host values in the GRANT tables must be IP addresses (or localhost).
Command line: --skip-name-resolve
Description: If set to 1, (0 is the default), the server does not listen for TCP/IP connections. All interaction with the server will be through socket files (Unix) or named pipes or shared memory (Windows). It's recommended to use this option if only local clients are permitted to connect to the server.
Command line: --skip-networking
Description: If set to 1, (0 is the default), only users with the SHOW DATABASES privilege can use the SHOW DATABASES statement to see all database names.
Command line: --skip-show-database
Description: Time in seconds. If a thread takes longer than this to launch, the slow_launch_threads server status variable is incremented.
Command line: --slow-launch-time=#
Description: If set to 0, the default unless the --slow-query-log option is used, the slow query log is disabled, while if set to 1 (both global and session variables), the slow query log is enabled. From MariaDB 10.11.0, an alias for log_slow_query.
Command line: --slow-query-log
See also: See log_output to see how log files are written. If that variable is set to NONE, no logs will be written even if slow_query_log is set to 1.
Description: Name of the slow query log file. From MariaDB 10.11, an alias for log_slow_query_file. If --log-basename is also set, slow_query_log_file should be placed after in the config files. Later settings override earlier settings, so log-basename will override any earlier log file name settings.
Command line: --slow-query-log-file=file_name
Default Value: host_name-slow.log
Description: On Unix-like systems, this is the name of the socket file used for local client connections, by default /tmp/mysql.sock, often changed by the distribution, for example /var/lib/mysql/mysql.sock. On Windows, this is the name of the named pipe used for local client connections, by default MySQL. On Windows, this is not case-sensitive.
Command line: --socket=name
Default Value: /tmp/mysql.sock (Unix), MySQL (Windows)
Description: Each session performing a sort allocates a buffer with this amount of memory. Not specific to any storage engine. If the status variable sort_merge_passes is too high, you may need to look at improving your query indexes, or increasing this. Consider reducing where there are many small sorts, such as OLTP, and increasing where needed by session. 16k is a suggested minimum.
Command line: --sort-buffer-size=#
Default Value: 2M (2097152) (some distributions increase the default)
Description: If set to 1, the query SELECT * FROM table_name WHERE auto_increment_column IS NULL will return an auto-increment that has just been successfully inserted, the same as the LAST_INSERT_ID() function. Some ODBC programs make use of this IS NULL comparison.
Description: If set to 0, MariaDB will not perform large SELECTs. See max_join_size for details. If max_join_size is set to anything but DEFAULT, sql_big_selects is automatically set to 0. If sql_big_selects is again set, max_join_size will be ignored.
Description: Old variable, which if set to 1, allows large result sets by saving all temporary sets to disk, avoiding 'table full' errors. No longer needed, as the server now handles this automatically.
Command line: --sql-big-tables
Description: If set to 1 (0 is default), results from SELECT statements are always placed into temporary tables. This can help the server when it takes a long time to send the results to the client by allowing the table locks to be freed early.
Description: If set to 1, adds an implicit IF EXISTS to ALTER, RENAME and DROP of TABLES, VIEWS, FUNCTIONS and PACKAGES. This variable is mainly used in replication to tag DDLs that can be ignored on the slave if the target table doesn't exist.
Command line: --sql-if-exists[={0|1}]
Description: If set to 1 (0 is the default), no logging to the general query log is done for the client. Only clients with the SUPER privilege can update this variable.
Removed: MariaDB/MySQL 5.5
Description: If set to 1 (0 is the default), for storage engines that use only table-level locking (Aria, MyISAM, MEMORY and MERGE), all INSERTs, UPDATEs, DELETEs and LOCK TABLE WRITEs will wait until there are no more SELECTs or LOCK TABLE READs pending on the relevant tables. Set this to 1 if reads are prioritized over writes.
Command line: --sql-low-priority-updates
Description: Sets the SQL Mode. Multiple modes can be set, separated by a comma.
Command line: --sql-mode=value[,value[,value...]]
Default Value:
STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
Valid Values: See SQL Mode for the full list.
Description: If set to 1, the default, warning_count is incremented each time a Note warning is encountered. If set to 0, Note warnings are not recorded. mariadb-dump has outputs to set this variable to 0 so that no unnecessary increments occur when data is reloaded. See also note_verbosity, which defines which notes should be given. The recommended way, as of MariaDB 10.6.16, to disable notes is to set note_verbosity to "".
Description: If set to 1, UPDATEs and DELETEs must be executed by using an index (simply mentioning an indexed column in a WHERE clause is not enough, optimizer must actually use it) or they must mention an indexed column and specify a LIMIT clause. Otherwise a statement will be aborted. Prevents the common mistake of accidentally deleting or updating every row in a table. Until MariaDB 10.3.11, could not be set as a command-line option or in my.cnf.
Command line: --sql-safe-updates[={0|1}]
Description: Maximum number of rows that can be returned from a SELECT query. Default is the maximum number of rows permitted per table by the server, usually 232-1 or 264-1. Can be restored to the default value after being changed by assigning it a value of DEFAULT. If a SELECT has a LIMIT clause, the LIMIT takes precedence over the value of the variable.
Default Value: 18446744073709551615
Description: If set to 1, single-row INSERTs will produce a string containing warning information if a warning occurs.
Command line: --standard-compliant-cte={0|1}
Description: Limit to the number of stored routines held in the stored procedures and stored functions caches. Each time a stored routine is executed, this limit is first checked, and if the number held in the cache exceeds this, that cache is flushed and memory freed.
Command line: --stored-program-cache=#
strict_password_validation
Description: When password validation plugins are enabled, reject passwords that cannot be validated (passwords specified as a hash). This excludes direct updates to the privilege tables.
Command line: --strict-password-validation
Description: If set to 1, the default, each time a non-temporary table is created, its .frm definition file is synced to disk. Fractionally slower, but safer in case of a crash.
Description: The system time zone is determined when the server starts. The system time zone is usually read from the operating system's environment but can be overridden by setting the 'TZ' environment variable before starting the server. See Time Zones: System Time Zone for the various ways to change the system time zone. This variable is not the same as the time_zone system variable, which is the variable that actually controls a session's active time zone. The system time zone is used for a session when time_zone is set to the special value SYSTEM.
Description: Number of table definitions that can be cached. Table definitions are taken from the .frm files, and if there are a large number of tables increasing the cache size can speed up table opening. Unlike the table_open_cache, as the table_definition_cache doesn't use file descriptors, and is much smaller.
Command line: --table-definition-cache=#
Description: Unused, and removed.
Command line: --table-lock-wait-timeout=#
Description: Maximum number of open tables cached in one table cache instance. See Optimizing table_open_cache for suggestions on optimizing. Increasing table_open_cache increases the number of file descriptors required.
Command line: --table-open-cache=#
table_open_cache_instances
Description: This system variable specifies the maximum number of table cache instances. MariaDB Server initially creates just a single instance. However, whenever it detects contention on the existing instances, it will automatically create a new instance. When the number of instances has been increased due to contention, it does not decrease again. The default value of this system variable is 8, which is expected to handle up to 100 CPU cores. If your system is larger than this, then you may benefit from increasing the value of this system variable.
Depending on the ratio of actual available file handles, and table_open_cache size, the max. instance count may be auto adjusted to a lower value on server startup.
The implementation and behavior of this feature is different than the same feature in MySQL 5.6.
Description: The interval, in seconds, between when successive keep-alive packets are sent if no acknowledgement is received. If set to 0, the system dependent default is used.
Command line: --tcp-keepalive-interval=#
Description: The number of unacknowledged probes to send before considering the connection dead and notifying the application layer. If set to 0, a system dependent default is used.
Command line: --tcp-keepalive-probes=#
Description: Timeout, in seconds, with no activity until the first TCP keep-alive packet is sent. If set to 0, a system dependent default is used.
Command line: --tcp-keepalive-time=#
Description: Set the TCP_NODELAY option (disable Nagle's algorithm) on socket.
Command line: --tcp-nodelay={0|1}
Description: Number of threads server caches for re-use. If this limit hasn't been reached, when a client disconnects, its threads are put into the cache, and re-used where possible. In MariaDB 10.MariaDB 5.5 and newer the threads are freed after 5 minutes of idle time. Normally this setting has little effect, as the other aspects of the thread implementation are more important, but increasing it can help servers with high volumes of connections per second so that most can use a cached, rather than a new, thread. The cache miss rate can be calculated as the server status variables threads_created/connections. If the thread pool is active, thread_cache_size is ignored. If thread_cache_size is set to greater than the value of max_connections, thread_cache_size will be set to the max_connections value.
Command line: --thread-cache-size=#
Default Value: 256 (adjusted if thread pool is active)
Description: Allows applications to give the system a hint about the desired number of threads. Specific to Solaris only, invokes thr_setconcurrency(). Deprecated and has no effect from MariaDB 5.5 .
Command line: --thread-concurrency=#
Description: Stack size for each thread. If set too small, limits recursion depth of stored procedures and complexity of SQL statements the server can handle in memory. Also affects limits in the crash-me test.
Command line: --thread-stack=#
Range: 131072 to 18446744073709551615
Description: The global value determines the default time zone for sessions that connect. The session value determines the session's active time zone. When it is set to SYSTEM, the session's time zone is determined by the system_time_zone system variable.
Command line: --default-time-zone=string
Description: Determines whether InnoDB mutexes are timed. OFF, the default, disables mutex timing, while ON enables it. See also SHOW ENGINE for more on mutex statistics. Deprecated and has no effect.
Command line: --timed-mutexes
Description: Sets the time for the client. This will affect the result returned by the NOW() function, not the SYSDATE() function, unless the server is started with the --sysdate-is-now option, in which case SYSDATE becomes an alias of NOW, and will also be affected. Also used to get the original timestamp when restoring rows from the binary log.
Valid Values: timestamp_value (Unix epoch timestamp, not MariaDB timestamp), DEFAULT
Description: Max size for data for an internal temporary on-disk MyISAM or Aria table. These tables are created as part of complex queries when the result doesn't fit into the memory engine. You can set this variable if you want to limit the size of temporary tables created in your temporary directory tmpdir.
Command line: --tmp-disk-table-size=#
Default Value: 18446744073709551615 (max unsigned integer, no limit)
Range: 1024 to 18446744073709551615
Command line: --tmp-memory-table-size=#
Description: The largest size for temporary tables in memory (not MEMORY tables) although if max_heap_table_size is smaller the lower limit will apply. You can see if it's necessary to increase by comparing the status variables Created_tmp_disk_tables and Created_tmp_tables to see how many temporary tables out of the total created needed to be converted to disk. Often complex GROUP BY queries are responsible for exceeding the limit. Defaults may be different on some systems, see for example Differences in MariaDB in Debian. From MariaDB 10.2.7, tmp_memory_table_size is an alias.
Command line: --tmp-table-size=#
Default Value: 16777216 (16MB)
Description: Directory for storing temporary tables and files. Can specify a list (separated by semicolons in Windows, and colons in Unix) that will then be used in round-robin fashion. This can be used for load balancing across several disks. Note that if the server is a replication replica, and slave_load_tmpdir, which overrides tmpdir for replicas, is not set, you should not set tmpdir to a directory that is cleared when the machine restarts, or else replication may fail.
Command line: --tmpdir=path or -t path
Default:
$TMPDIR (environment variable) if set
otherwise $TEMP if set and on Windows
otherwise $TMP if set and on Windows
otherwise P_tmpdir ("/tmp") or C:\TEMP (unless overridden during buid time)
transaction_alloc_block_size
Description: Size in bytes to increase the memory pool available to each transaction when the available pool is not large enough. See transaction_prealloc_size.
Command line: --transaction-alloc-block-size=#
Range: 1024 to 134217728 (128M)
Command line: --transaction-isolation=name
Default Value: REPEATABLE-READ
Valid Values: READ-UNCOMMITTED, READ-COMMITTED, REPEATABLE-READ, SERIALIZABLE
transaction_prealloc_size
Description: Initial size of a memory pool available to each transaction for various memory allocations. If the memory pool is not large enough for an allocation, it is increased by transaction_alloc_block_size bytes, and truncated back to transaction_prealloc_size bytes when the transaction is completed. If set large enough to contain all statements in a transaction, extra malloc() calls are avoided.
Command line: --transaction-prealloc-size=#
Range: 1024 to 134217728 (128M)
Description: Default transaction access mode. If set to OFF, the default, access is read/write. If set to ON, access is read-only. The SET TRANSACTION statement can also change the value of this variable. See SET TRANSACTION and START TRANSACTION.
Command line: --transaction-isolation=name
Default Value: REPEATABLE-READ
Valid Values: READ-UNCOMMITTED, READ-COMMITTED, REPEATABLE-READ, SERIALIZABLE
Description: Default transaction access mode. If set to OFF, the default, access is read/write. If set to ON, access is read-only. The SET TRANSACTION statement can also change the value of this variable. See SET TRANSACTION and START TRANSACTION. In MariaDB 11.1, this system variable is deprecated and replaced by transaction_read_only.
Command line: --transaction-read-only=#
Description: If set to 0, storage engines can (but are not required to) assume that duplicate keys are not present in input data. If set to 0, inserting duplicates into a UNIQUE index can succeed, causing the table to become corrupted. Set to 0 to speed up imports of large tables to InnoDB.
updatable_views_with_limit
Description: Determines whether view updates can be made with an UPDATE or DELETE statement with a LIMIT clause if the view does not contain all primary or not null unique key columns from the underlying table. 0 prohibits this, while 1 permits it while issuing a warning (the default).
Command line: --updatable-views-with-limit=#
Description: Controls the use of engine-independent table statistics.
never: The optimizer will not use data from statistics tables.
complementary: The optimizer uses data from statistics tables if the same kind of data is not provided by the storage engine.
preferably: Prefer the data from statistics tables, if it's not available there, use the data from the storage engine.
complementary_for_queries: Same as complementary, but for queries only (to avoid needlessly collecting for ANALYZE TABLE).
preferably_for_queries: Same as preferably, but for queries only (to avoid needlessly collecting for ANALYZE TABLE).
Command line: --use-stat-tables=mode
Default Value: preferably_for_queries
Description: Server version number. It may also include a suffix with configuration or build information. -debug indicates debugging support was enabled on the server, and -log indicates at least one of the binary log, general log or slow query log are enabled, for example 10.0.1-MariaDB-mariadb1precise-log. Can be set at startup in order to fake the server version.
Command line: -V, --version[=name]
Description: Value of the COMPILATION_COMMENT option specified by CMake when building MariaDB, for example mariadb.org binary distribution.
Description: The machine type or architecture MariaDB was built on, for example i686.
Description: Operating system that MariaDB was built on, for example debian-linux-gnu.
Description: Version of the used malloc library.
Description: Source control revision id for MariaDB source code, enabling one to see exactly which version of the source was used for a build.
Description: Time in seconds that the server waits for a connection to become active before closing it. The session value is initialized when a thread starts up from either the global value, if the connection is non-interactive, or from the interactive_timeout value, if the connection is interactive.
Command line: --wait-timeout=#
Range: (Windows): 1 to 2147483
Range: (Other): 1 to 31536000
Description: Read-only variable indicating the number of warnings, errors and notes resulting from the most recent statement that generated messages. See SHOW WARNINGS for more. Note warnings will only be recorded if sql_notes is true (the default).
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