5.1.6 Server Command Options

When you start the mysqld server, you can specify program options using any of the methods described in Section 4.2.2, “Specifying Program Options”. The most common methods are to provide options in an option file or on the command line. However, in most cases it is desirable to make sure that the server uses the same options each time it runs. The best way to ensure this is to list them in an option file. See Section 4.2.2.2, “Using Option Files”. That section also describes option file format and syntax.

mysqld reads options from the [mysqld] and [server] groups. mysqld_safe reads options from the [mysqld], [server], [mysqld_safe], and [safe_mysqld] groups. mysql.server reads options from the [mysqld] and [mysql.server] groups.

An embedded MySQL server usually reads options from the [server], [embedded], and [xxxxx_SERVER] groups, where xxxxx is the name of the application into which the server is embedded.

mysqld accepts many command options. For a brief summary, execute this command:

mysqld --help

To see the full list, use this command:

mysqld --verbose --help

Some of the items in the list are actually system variables that can be set at server startup. These can be displayed at runtime using the SHOW VARIABLES statement. Some items displayed by the preceding mysqld command do not appear in SHOW VARIABLES output; this is because they are options only and not system variables.

The following list shows some of the most common server options. Additional options are described in other sections:

• Options that affect security: See Section 6.1.4, “Security-Related mysqld Options and Variables”.

• SSL-related options: See Command Options for Encrypted Connections.

• Binary log control options: See Section 5.4.4, “The Binary Log”.

• Replication-related options: See Section 16.1.6, “Replication and Binary Logging Options and Variables”.

• Options for loading plugins such as pluggable storage engines: See Section 5.5.1, “Installing and Uninstalling Plugins”.

• Options specific to particular storage engines: See Section 14.15, “InnoDB Startup Options and System Variables” and Section 15.2.1, “MyISAM Startup Options”.

Some options control the size of buffers or caches. For a given buffer, the server might need to allocate internal data structures. These structures typically are allocated from the total memory allocated to the buffer, and the amount of space required might be platform dependent. This means that when you assign a value to an option that controls a buffer size, the amount of space actually available might differ from the value assigned. In some cases, the amount might be less than the value assigned. It is also possible that the server adjusts a value upward. For example, if you assign a value of 0 to an option for which the minimal value is 1024, the server sets the value to 1024.

Values for buffer sizes, lengths, and stack sizes are given in bytes unless otherwise specified.

Some options take file name values. Unless otherwise specified, the default file location is the data directory if the value is a relative path name. To specify the location explicitly, use an absolute path name. Suppose that the data directory is /var/mysql/data. If a file-valued option is given as a relative path name, it is located under /var/mysql/data. If the value is an absolute path name, its location is as given by the path name.

You can also set the values of server system variables at server startup by using variable names as options. To assign a value to a server system variable, use an option of the form --var_name=value. For example, --sort_buffer_size=384M sets the sort_buffer_size variable to a value of 384MB.

When you assign a value to a variable, MySQL might automatically correct the value to stay within a given range, or adjust the value to the closest permissible value if only certain values are permitted.

To restrict the maximum value to which a system variable can be set at runtime with the SET statement, specify this maximum by using an option of the form --maximum-var_name=value at server startup.

You can change the values of most system variables at runtime with the SET statement. See Section 13.7.4.1, “SET Syntax for Variable Assignment”.

Section 5.1.7, “Server System Variables”, provides a full description for all variables, and additional information for setting them at server startup and runtime. For information on changing system variables, see Section 5.1.1, “Configuring the Server”.

• --help, -?

  Command-Line Format	--help

  Display a short help message and exit. Use both the --verbose and --help options to see the full message.

• --allow-suspicious-udfs

  Command-Line Format	--allow-suspicious-udfs[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  This option controls whether loadable functions that have only an xxx symbol for the main function can be loaded. By default, the option is off and only loadable functions that have at least one auxiliary symbol can be loaded; this prevents attempts at loading functions from shared object files other than those containing legitimate functions. See Loadable Function Security Precautions.

• --ansi

  Command-Line Format	--ansi

  Use standard (ANSI) SQL syntax instead of MySQL syntax. For more precise control over the server SQL mode, use the --sql-mode option instead. See Section 1.6, “MySQL Standards Compliance”, and Section 5.1.10, “Server SQL Modes”.

• --basedir=dir_name, -b dir_name

  Command-Line Format	--basedir=dir_name
  System Variable	basedir
  Scope	Global
  Dynamic	No
  Type	Directory name
  Default Value	configuration-dependent default

  The path to the MySQL installation directory. This option sets the basedir system variable.

• --bootstrap

  Command-Line Format	--bootstrap
  Deprecated	Yes

  This option is used by the mysql_install_db program to create the MySQL privilege tables without having to start a full MySQL server.

  Note

  mysql_install_db is deprecated because its functionality has been integrated into mysqld, the MySQL server. Consequently, the --bootstrap server option that mysql_install_db passes to mysqld is also deprecated. To initialize a MySQL installation, invoke mysqld with the --initialize or --initialize-insecure option. For more information, see Section 2.9.1, “Initializing the Data Directory”. Expect mysql_install_db and the --bootstrap server option to be removed in a future release of MySQL.

  --bootstrap is mutually exclusive with --daemonize, --initialize, and --initialize-insecure.

  Global transaction identifiers (GTIDs) are not disabled when --bootstrap is used. --bootstrap was used (Bug #20980271). See Section 16.1.3, “Replication with Global Transaction Identifiers”.

  When the server operates in bootstap mode, some functionality is unavailable that limits the statements permitted in any file named by the init_file system variable. For more information, see the description of that variable. In addition, the disabled_storage_engines system variable has no effect.

• --character-set-client-handshake

  Command-Line Format	--character-set-client-handshake[={OFF|ON}]
  Type	Boolean
  Default Value	ON

  Do not ignore character set information sent by the client. To ignore client information and use the default server character set, use --skip-character-set-client-handshake; this makes MySQL behave like MySQL 4.0.

• --chroot=dir_name, -r dir_name

  Command-Line Format	--chroot=dir_name
  Type	Directory name

  Put the mysqld server in a closed environment during startup by using the chroot() system call. This is a recommended security measure. Use of this option somewhat limits LOAD DATA and SELECT ... INTO OUTFILE.

• --console

  Command-Line Format	--console
  Platform Specific	Windows

  (Windows only.) Write the error log to stderr and stdout (the console). mysqld does not close the console window if this option is used.

  --console takes precedence over --log-error if both are given. (In MySQL 5.5 and 5.6, this is reversed: --log-error takes precedence over --console if both are given.)

• --core-file

  Command-Line Format	--core-file

  When this option is used, write a core file if mysqld dies; no arguments are needed (or accepted). The name and location of the core file is system dependent. On Linux, a core file named core.pid is written to the current working directory of the process, which for mysqld is the data directory. pid represents the process ID of the server process. On macOS, a core file named core.pid is written to the /cores directory. On Solaris, use the coreadm command to specify where to write the core file and how to name it.

  For some systems, to get a core file you must also specify the --core-file-size option to mysqld_safe. See Section 4.3.2, “mysqld_safe — MySQL Server Startup Script”. On some systems, such as Solaris, you do not get a core file if you are also using the --user option. There might be additional restrictions or limitations. For example, it might be necessary to execute ulimit -c unlimited before starting the server. Consult your system documentation.

• --daemonize

  Command-Line Format	--daemonize[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  This option causes the server to run as a traditional, forking daemon, permitting it to work with operating systems that use systemd for process control. For more information, see Section 2.5.10, “Managing MySQL Server with systemd”.

  --daemonize is mutually exclusive with --bootstrap, --initialize, and --initialize-insecure.

• --datadir=dir_name, -h dir_name

  Command-Line Format	--datadir=dir_name
  System Variable	datadir
  Scope	Global
  Dynamic	No
  Type	Directory name

  The path to the MySQL server data directory. This option sets the datadir system variable. See the description of that variable.

• --debug[=debug_options], -# [debug_options]

  Command-Line Format	--debug[=debug_options]
  System Variable	debug
  Scope	Global, Session
  Dynamic	Yes
  Type	String
  Default Value (Unix)	d:t:i:o,/tmp/mysqld.trace
  Default Value (Windows)	d:t:i:O,\mysqld.trace

  If MySQL is configured with the -DWITH_DEBUG=1 CMake option, you can use this option to get a trace file of what mysqld is doing. A typical debug_options string is d:t:o,file_name. The default is d:t:i:o,/tmp/mysqld.trace on Unix and d:t:i:O,\mysqld.trace on Windows.

  Using -DWITH_DEBUG=1 to configure MySQL with debugging support enables you to use the --debug="d,parser_debug" option when you start the server. This causes the Bison parser that is used to process SQL statements to dump a parser trace to the server's standard error output. Typically, this output is written to the error log.

  This option may be given multiple times. Values that begin with + or - are added to or subtracted from the previous value. For example, --debug=T --debug=+P sets the value to P:T.

  For more information, see Section 5.8.3, “The DBUG Package”.

• --debug-sync-timeout[=N]

  Command-Line Format	--debug-sync-timeout[=#]
  Type	Integer

  Controls whether the Debug Sync facility for testing and debugging is enabled. Use of Debug Sync requires that MySQL be configured with the -DWITH_DEBUG=ON CMake option (see Section 2.8.7, “MySQL Source-Configuration Options”). If Debug Sync is not compiled in, this option is not available. The option value is a timeout in seconds. The default value is 0, which disables Debug Sync. To enable it, specify a value greater than 0; this value also becomes the default timeout for individual synchronization points. If the option is given without a value, the timeout is set to 300 seconds.

  For a description of the Debug Sync facility and how to use synchronization points, see MySQL Internals: Test Synchronization.

• --default-time-zone=timezone

  Command-Line Format	--default-time-zone=name
  Type	String

  Set the default server time zone. This option sets the global time_zone system variable. If this option is not given, the default time zone is the same as the system time zone (given by the value of the system_time_zone system variable.

  The system_time_zone variable differs from time_zone. Although they might have the same value, the latter variable is used to initialize the time zone for each client that connects. See Section 5.1.13, “MySQL Server Time Zone Support”.

• --defaults-extra-file=file_name

  Read this option file after the global option file but (on Unix) before the user option file. If the file does not exist or is otherwise inaccessible, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory. This must be the first option on the command line if it is used.

  For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.

• --defaults-file=file_name

  Read only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.

  Note

  This must be the first option on the command line if it is used, except that if the server is started with the --defaults-file and --install (or --install-manual) options, --install (or --install-manual) must be first.

  For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.

• --defaults-group-suffix=str

  Read not only the usual option groups, but also groups with the usual names and a suffix of str. For example, mysqld normally reads the [mysqld] group. If this option is given as --defaults-group-suffix=_other, mysqld also reads the [mysqld_other] group.

  For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.

• --des-key-file=file_name

  Command-Line Format	--des-key-file=file_name
  Deprecated	Yes

  Read the default DES keys from this file. These keys are used by the DES_ENCRYPT() and DES_DECRYPT() functions.

  Note

  The DES_ENCRYPT() and DES_DECRYPT() functions are deprecated in MySQL 5.7, are removed in MySQL 8.0, and should no longer be used. Consequently, --des-key-file also is deprecated and is removed in MySQL 8.0.

• --disable-partition-engine-check

  Command-Line Format	--disable-partition-engine-check[={OFF|ON}]
  Introduced	5.7.17
  Deprecated	5.7.17
  Type	Boolean
  Default Value (≥ 5.7.21)	ON
  Default Value (≥ 5.7.17, ≤ 5.7.20)	OFF

  Whether to disable the startup check for tables with nonnative partitioning.

  As of MySQL 5.7.17, the generic partitioning handler in the MySQL server is deprecated, and is removed in MySQL 8.0, when the storage engine used for a given table is expected to provide its own (“native”) partitioning handler. Currently, only the InnoDB and NDB storage engines do this.

  Use of tables with nonnative partitioning results in an ER_WARN_DEPRECATED_SYNTAX warning. In MySQL 5.7.17 through 5.7.20, the server automatically performs a check at startup to identify tables that use nonnative partitioning; for any that are found, the server writes a message to its error log. To disable this check, use the --disable-partition-engine-check option. In MySQL 5.7.21 and later, this check is not performed; in these versions, you must start the server with --disable-partition-engine-check=false, if you wish for the server to check for tables using the generic partitioning handler (Bug #85830, Bug #25846957).

  Use of tables with nonnative partitioning results in an ER_WARN_DEPRECATED_SYNTAX warning. Also, the server performs a check at startup to identify tables that use nonnative partitioning; for any found, the server writes a message to its error log. To disable this check, use the --disable-partition-engine-check option.

  To prepare for migration to MySQL 8.0, any table with nonnative partitioning should be changed to use an engine that provides native partitioning, or be made nonpartitioned. For example, to change a table to InnoDB, execute this statement:

  ALTER TABLE table_name ENGINE = INNODB;

• --early-plugin-load=plugin_list

  Command-Line Format	--early-plugin-load=plugin_list
  Introduced	5.7.11
  Type	String
  Default Value (≥ 5.7.12)	empty string
  Default Value (5.7.11)	keyring_file plugin library file name

  This option tells the server which plugins to load before loading mandatory built-in plugins and before storage engine initialization. Early loading is supported only for plugins compiled with PLUGIN_OPT_ALLOW_EARLY. If multiple --early-plugin-load options are given, only the last one applies.

  The option value is a semicolon-separated list of plugin_library and name=plugin_library values. Each plugin_library is the name of a library file that contains plugin code, and each name is the name of a plugin to load. If a plugin library is named without any preceding plugin name, the server loads all plugins in the library. With a preceding plugin name, the server loads only the named plugin from the libary. The server looks for plugin library files in the directory named by the plugin_dir system variable.

  For example, if plugins named myplug1 and myplug2 are contained in the plugin library files myplug1.so and myplug2.so, use this option to perform an early plugin load:

  mysqld --early-plugin-load="myplug1=myplug1.so;myplug2=myplug2.so"

  Quotes surround the argument value because otherwise some command interpreters interpret semicolon (;) as a special character. (For example, Unix shells treat it as a command terminator.)

  Each named plugin is loaded early for a single invocation of mysqld only. After a restart, the plugin is not loaded early unless --early-plugin-load is used again.

  If the server is started using --initialize or --initialize-insecure, plugins specified by --early-plugin-load are not loaded.

  If the server is run with --help, plugins specified by --early-plugin-load are loaded but not initialized. This behavior ensures that plugin options are displayed in the help message.

  InnoDB tablespace encryption relies on the MySQL Keyring for encryption key management, and the keyring plugin to be used must be loaded prior to storage engine initialization to facilitate InnoDB recovery for encrypted tables. For example, administrators who want the keyring_file plugin loaded at startup should use --early-plugin-load with the appropriate option value (such as keyring_file.so on Unix and Unix-like systems or keyring_file.dll on Windows).

  Important

  In MySQL 5.7.11, the default --early-plugin-load value is the name of the keyring_file plugin library file, causing that plugin to be loaded by default. In MySQL 5.7.12 and higher, the default --early-plugin-load value is empty; to load the keyring_file plugin, you must explicitly specify the option with a value naming the keyring_file plugin library file.

  This change of default --early-plugin-load value introduces an incompatibility for InnoDB tablespace encryption for upgrades from 5.7.11 to 5.7.12 or higher. Administrators who have encrypted InnoDB tablespaces must take explicit action to ensure continued loading of the keyring plugin: Start the server with an --early-plugin-load option that names the plugin library file. For additional information, see Section 6.4.4.1, “Keyring Plugin Installation”.

  For information about InnoDB tablespace encryption, see Section 14.14, “InnoDB Data-at-Rest Encryption”. For general information about plugin loading, see Section 5.5.1, “Installing and Uninstalling Plugins”.

• --exit-info[=flags], -T [flags]

  Command-Line Format	--exit-info[=flags]
  Type	Integer

  This is a bitmask of different flags that you can use for debugging the mysqld server. Do not use this option unless you know exactly what it does!

• --external-locking

  Command-Line Format	--external-locking[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  Enable external locking (system locking), which is disabled by default. If you use this option on a system on which lockd does not fully work (such as Linux), it is easy for mysqld to deadlock.

  To disable external locking explicitly, use --skip-external-locking.

  External locking affects only MyISAM table access. For more information, including conditions under which it can and cannot be used, see Section 8.11.5, “External Locking”.

• --flush

  Command-Line Format	--flush[={OFF|ON}]
  System Variable	flush
  Scope	Global
  Dynamic	Yes
  Type	Boolean
  Default Value	OFF

  Flush (synchronize) all changes to disk after each SQL statement. Normally, MySQL does a write of all changes to disk only after each SQL statement and lets the operating system handle the synchronizing to disk. See Section B.3.3.3, “What to Do If MySQL Keeps Crashing”.

  Note

  If --flush is specified, the value of flush_time does not matter and changes to flush_time have no effect on flush behavior.

• --gdb

  Command-Line Format	--gdb[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  Install an interrupt handler for SIGINT (needed to stop mysqld with ^C to set breakpoints) and disable stack tracing and core file handling. See Section 5.8.1.4, “Debugging mysqld under gdb”.

• --ignore-db-dir=dir_name

  Command-Line Format	--ignore-db-dir=dir_name
  Deprecated	5.7.16
  Type	Directory name

  This option tells the server to ignore the given directory name for purposes of the SHOW DATABASES statement or INFORMATION_SCHEMA tables. For example, if a MySQL configuration locates the data directory at the root of a file system on Unix, the system might create a lost+found directory there that the server should ignore. Starting the server with --ignore-db-dir=lost+found causes that name not to be listed as a database.

  To specify more than one name, use this option multiple times, once for each name. Specifying the option with an empty value (that is, as --ignore-db-dir=) resets the directory list to the empty list.

  Instances of this option given at server startup are used to set the ignore_db_dirs system variable.

  This option is deprecated in MySQL 5.7. With the introduction of the data dictionary in MySQL 8.0, it became superfluous and was removed in that version.

• --initialize

  Command-Line Format	--initialize[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  This option is used to initialize a MySQL installation by creating the data directory and populating the tables in the mysql system database. For more information, see Section 2.9.1, “Initializing the Data Directory”.

  This option limits the effects of, or is not compatible with, a number of other startup options for the MySQL server. Some of the most common issues of this sort are noted here:

  • We strongly recommend, when initializing the data directory with --initialize, that you specify no additional options other than --datadir, other options used for setting directory locations such as --basedir, and possibly --user, if required. Options for the running MySQL server can be specified when starting it once initialization has been completed and mysqld has shut down. This also applies when using --initialize-insecure instead of --initialize.

  • When the server is started with --initialize, some functionality is unavailable that limits the statements permitted in any file named by the init_file system variable. For more information, see the description of that variable. In addition, the disabled_storage_engines system variable has no effect.

  • The --ndbcluster option is ignored when used together with --initialize.

  • --initialize is mutually exclusive with --bootstrap and --daemonize.

  The items in the preceding list also apply when initializing the server using the --initialize-insecure option.

• --initialize-insecure

  Command-Line Format	--initialize-insecure[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  This option is used to initialize a MySQL installation by creating the data directory and populating the tables in the mysql system database. This option implies --initialize, and the same restrictions and limitations apply; for more information, see the description of that option, and Section 2.9.1, “Initializing the Data Directory”.

  Warning

  This option creates a MySQL root user with an empty password, which is insecure. For this reason, do not use it in production without setting this password manually. See Post-Initialization root Password Assignment, for information about how to do this.

• --innodb-xxx

  Set an option for the InnoDB storage engine. The InnoDB options are listed in Section 14.15, “InnoDB Startup Options and System Variables”.

• --install [service_name]

  Command-Line Format	--install [service_name]
  Platform Specific	Windows

  (Windows only) Install the server as a Windows service that starts automatically during Windows startup. The default service name is MySQL if no service_name value is given. For more information, see Section 2.3.4.8, “Starting MySQL as a Windows Service”.

  Note

  If the server is started with the --defaults-file and --install options, --install must be first.

• --install-manual [service_name]

  Command-Line Format	--install-manual [service_name]
  Platform Specific	Windows

  (Windows only) Install the server as a Windows service that must be started manually. It does not start automatically during Windows startup. The default service name is MySQL if no service_name value is given. For more information, see Section 2.3.4.8, “Starting MySQL as a Windows Service”.

  Note

  If the server is started with the --defaults-file and --install-manual options, --install-manual must be first.

• --language=lang_name, -L lang_name

  Command-Line Format	--language=name
  Deprecated	Yes; use lc-messages-dir instead
  System Variable	language
  Scope	Global
  Dynamic	No
  Type	Directory name
  Default Value	/usr/local/mysql/share/mysql/english/

  The language to use for error messages. lang_name can be given as the language name or as the full path name to the directory where the language files are installed. See Section 10.12, “Setting the Error Message Language”.

  --lc-messages-dir and --lc-messages should be used rather than --language, which is deprecated (and handled as a synonym for --lc-messages-dir). You should expect the --language option to be removed in a future release of MySQL.

• --large-pages

  Command-Line Format	--large-pages[={OFF|ON}]
  System Variable	large_pages
  Scope	Global
  Dynamic	No
  Platform Specific	Linux
  Type	Boolean
  Default Value	OFF

  Some hardware/operating system architectures support memory pages greater than the default (usually 4KB). The actual implementation of this support depends on the underlying hardware and operating system. Applications that perform a lot of memory accesses may obtain performance improvements by using large pages due to reduced Translation Lookaside Buffer (TLB) misses.

  MySQL supports the Linux implementation of large page support (which is called HugeTLB in Linux). See Section 8.12.4.3, “Enabling Large Page Support”. For Solaris support of large pages, see the description of the --super-large-pages option.

  --large-pages is disabled by default.

• --lc-messages=locale_name

  Command-Line Format	--lc-messages=name
  System Variable	lc_messages
  Scope	Global, Session
  Dynamic	Yes
  Type	String
  Default Value	en_US

  The locale to use for error messages. The default is en_US. The server converts the argument to a language name and combines it with the value of --lc-messages-dir to produce the location for the error message file. See Section 10.12, “Setting the Error Message Language”.

• --lc-messages-dir=dir_name

  Command-Line Format	--lc-messages-dir=dir_name
  System Variable	lc_messages_dir
  Scope	Global
  Dynamic	No
  Type	Directory name

  The directory where error messages are located. The server uses the value together with the value of --lc-messages to produce the location for the error message file. See Section 10.12, “Setting the Error Message Language”.

• --local-service

  Command-Line Format	--local-service

  (Windows only) A --local-service option following the service name causes the server to run using the LocalService Windows account that has limited system privileges. If both --defaults-file and --local-service are given following the service name, they can be in any order. See Section 2.3.4.8, “Starting MySQL as a Windows Service”.

• --log-error[=file_name]

  Command-Line Format	--log-error[=file_name]
  System Variable	log_error
  Scope	Global
  Dynamic	No
  Type	File name

  Write the error log and startup messages to this file. See Section 5.4.2, “The Error Log”.

  If the option names no file, the error log file name on Unix and Unix-like systems is host_name.err in the data directory. The file name on Windows is the same, unless the --pid-file option is specified. In that case, the file name is the PID file base name with a suffix of .err in the data directory.

  If the option names a file, the error log file has that name (with an .err suffix added if the name has no suffix), located under the data directory unless an absolute path name is given to specify a different location.

  On Windows, --console takes precedence over --log-error if both are given. In this case, the server writes the error log to the console rather than to a file. (In MySQL 5.5 and 5.6, this is reversed: --log-error takes precedence over --console if both are given.)

• --log-isam[=file_name]

  Command-Line Format	--log-isam[=file_name]
  Type	File name

  Log all MyISAM changes to this file (used only when debugging MyISAM).

• --log-raw

  Command-Line Format	--log-raw[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  Passwords in certain statements written to the general query log, slow query log, and binary log are rewritten by the server not to occur literally in plain text. Password rewriting can be suppressed for the general query log by starting the server with the --log-raw option. This option may be useful for diagnostic purposes, to see the exact text of statements as received by the server, but for security reasons is not recommended for production use.

  If a query rewrite plugin is installed, the --log-raw option affects statement logging as follows:

  • Without --log-raw, the server logs the statement returned by the query rewrite plugin. This may differ from the statement as received.

  • With --log-raw, the server logs the original statement as received.

  For more information, see Section 6.1.2.3, “Passwords and Logging”.

• --log-short-format

  Command-Line Format	--log-short-format[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  Log less information to the slow query log, if it has been activated.

• --log-tc=file_name

  Command-Line Format	--log-tc=file_name
  Type	File name
  Default Value	tc.log

  The name of the memory-mapped transaction coordinator log file (for XA transactions that affect multiple storage engines when the binary log is disabled). The default name is tc.log. The file is created under the data directory if not given as a full path name. This option is unused.

• --log-tc-size=size

  Command-Line Format	--log-tc-size=#
  Type	Integer
  Default Value (64-bit platforms, ≥ 5.7.21)	6 * page size
  Default Value (64-bit platforms, ≤ 5.7.20)	24576
  Default Value (32-bit platforms, ≥ 5.7.21)	6 * page size
  Default Value (32-bit platforms, ≤ 5.7.20)	24576
  Minimum Value	6 * page size
  Maximum Value (64-bit platforms)	18446744073709551615
  Maximum Value (32-bit platforms)	4294967295

  The size in bytes of the memory-mapped transaction coordinator log. The default and minimum values are 6 times the page size, and the value must be a multiple of the page size. (Before MySQL 5.7.21, the default size is 24KB.)

• --log-warnings[=level], -W [level]

  Command-Line Format	--log-warnings[=#]
  Deprecated	Yes
  System Variable	log_warnings
  Scope	Global
  Dynamic	Yes
  Type	Integer
  Default Value	2
  Minimum Value	0
  Maximum Value (64-bit platforms)	18446744073709551615
  Maximum Value (32-bit platforms)	4294967295

  Note

  The log_error_verbosity system variable is preferred over, and should be used instead of, the --log-warnings option or log_warnings system variable. For more information, see the descriptions of log_error_verbosity and log_warnings. The --log-warnings command-line option and log_warnings system variable are deprecated; expect them to be removed in a future release of MySQL.

  Whether to produce additional warning messages to the error log. This option is enabled by default. To disable it, use --log-warnings=0. Specifying the option without a level value increments the current value by 1. The server logs messages about statements that are unsafe for statement-based logging if the value is greater than 0. Aborted connections and access-denied errors for new connection attempts are logged if the value is greater than 1. See Section B.3.2.9, “Communication Errors and Aborted Connections”.

• --memlock

  Command-Line Format	--memlock[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  Lock the mysqld process in memory. This option might help if you have a problem where the operating system is causing mysqld to swap to disk.

  --memlock works on systems that support the mlockall() system call; this includes Solaris, most Linux distributions that use a 2.4 or higher kernel, and perhaps other Unix systems. On Linux systems, you can tell whether or not mlockall() (and thus this option) is supported by checking to see whether or not it is defined in the system mman.h file, like this:

  $> grep mlockall /usr/include/sys/mman.h

  If mlockall() is supported, you should see in the output of the previous command something like the following:

  extern int mlockall (int __flags) __THROW;

  Important

  Use of this option may require you to run the server as root, which, for reasons of security, is normally not a good idea. See Section 6.1.5, “How to Run MySQL as a Normal User”.

  On Linux and perhaps other systems, you can avoid the need to run the server as root by changing the limits.conf file. See the notes regarding the memlock limit in Section 8.12.4.3, “Enabling Large Page Support”.

  You must not use this option on a system that does not support the mlockall() system call; if you do so, mysqld is very likely to exit as soon as you try to start it.

• --myisam-block-size=N

  Command-Line Format	--myisam-block-size=#
  Type	Integer
  Default Value	1024
  Minimum Value	1024
  Maximum Value	16384

  The block size to be used for MyISAM index pages.

• --no-defaults

  Do not read any option files. If program startup fails due to reading unknown options from an option file, --no-defaults can be used to prevent them from being read. This must be the first option on the command line if it is used.

  For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.

• --old-style-user-limits

  Command-Line Format	--old-style-user-limits[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  Enable old-style user limits. (Before MySQL 5.0.3, account resource limits were counted separately for each host from which a user connected rather than per account row in the user table.) See Section 6.2.16, “Setting Account Resource Limits”.

• --partition[=value]

  Command-Line Format	--partition[={OFF|ON}]
  Deprecated	5.7.16
  Disabled by	skip-partition
  Type	Boolean
  Default Value	ON

  Enables or disables user-defined partitioning support in the MySQL Server.

  This option is deprecated in MySQL 5.7.16, and is removed from MySQL 8.0 because in MySQL 8.0, the partitioning engine is replaced by native partitioning, which cannot be disabled.

• --performance-schema-xxx

  Configure a Performance Schema option. For details, see Section 25.14, “Performance Schema Command Options”.

• --plugin-load=plugin_list

  Command-Line Format	--plugin-load=plugin_list
  Type	String

  This option tells the server to load the named plugins at startup. If multiple --plugin-load options are given, only the last one applies. Additional plugins to load may be specified using --plugin-load-add options.

  The option value is a semicolon-separated list of plugin_library and name=plugin_library values. Each plugin_library is the name of a library file that contains plugin code, and each name is the name of a plugin to load. If a plugin library is named without any preceding plugin name, the server loads all plugins in the library. With a preceding plugin name, the server loads only the named plugin from the libary. The server looks for plugin library files in the directory named by the plugin_dir system variable.

  For example, if plugins named myplug1 and myplug2 are contained in the plugin library files myplug1.so and myplug2.so, use this option to perform an early plugin load:

  mysqld --plugin-load="myplug1=myplug1.so;myplug2=myplug2.so"

  Quotes surround the argument value because otherwise some command interpreters interpret semicolon (;) as a special character. (For example, Unix shells treat it as a command terminator.)

  Each named plugin is loaded for a single invocation of mysqld only. After a restart, the plugin is not loaded unless --plugin-load is used again. This is in contrast to INSTALL PLUGIN, which adds an entry to the mysql.plugins table to cause the plugin to be loaded for every normal server startup.

  During the normal startup sequence, the server determines which plugins to load by reading the mysql.plugins system table. If the server is started with the --skip-grant-tables option, plugins registered in the mysql.plugins table are not loaded and are unavailable. --plugin-load enables plugins to be loaded even when --skip-grant-tables is given. --plugin-load also enables plugins to be loaded at startup that cannot be loaded at runtime.

  This option does not set a corresponding system variable. The output of SHOW PLUGINS provides information about loaded plugins. More detailed information can be found in the Information Schema PLUGINS table. See Section 5.5.2, “Obtaining Server Plugin Information”.

  For additional information about plugin loading, see Section 5.5.1, “Installing and Uninstalling Plugins”.

• --plugin-load-add=plugin_list

  Command-Line Format	--plugin-load-add=plugin_list
  Type	String

  This option complements the --plugin-load option. --plugin-load-add adds a plugin or plugins to the set of plugins to be loaded at startup. The argument format is the same as for --plugin-load. --plugin-load-add can be used to avoid specifying a large set of plugins as a single long unwieldy --plugin-load argument.

  --plugin-load-add can be given in the absence of --plugin-load, but any instance of --plugin-load-add that appears before --plugin-load. has no effect because --plugin-load resets the set of plugins to load. In other words, these options:

  --plugin-load=x --plugin-load-add=y

  are equivalent to this option:

  --plugin-load="x;y"

  But these options:

  --plugin-load-add=y --plugin-load=x

  are equivalent to this option:

  --plugin-load=x

  This option does not set a corresponding system variable. The output of SHOW PLUGINS provides information about loaded plugins. More detailed information can be found in the Information Schema PLUGINS table. See Section 5.5.2, “Obtaining Server Plugin Information”.

  For additional information about plugin loading, see Section 5.5.1, “Installing and Uninstalling Plugins”.

• --plugin-xxx

  Specifies an option that pertains to a server plugin. For example, many storage engines can be built as plugins, and for such engines, options for them can be specified with a --plugin prefix. Thus, the --innodb-file-per-table option for InnoDB can be specified as --plugin-innodb-file-per-table.

  For boolean options that can be enabled or disabled, the --skip prefix and other alternative formats are supported as well (see Section 4.2.2.4, “Program Option Modifiers”). For example, --skip-plugin-innodb-file-per-table disables innodb-file-per-table.

  The rationale for the --plugin prefix is that it enables plugin options to be specified unambiguously if there is a name conflict with a built-in server option. For example, were a plugin writer to name a plugin “sql” and implement a “mode” option, the option name might be --sql-mode, which would conflict with the built-in option of the same name. In such cases, references to the conflicting name are resolved in favor of the built-in option. To avoid the ambiguity, users can specify the plugin option as --plugin-sql-mode. Use of the --plugin prefix for plugin options is recommended to avoid any question of ambiguity.

• --port=port_num, -P port_num

  Command-Line Format	--port=port_num
  System Variable	port
  Scope	Global
  Dynamic	No
  Type	Integer
  Default Value	3306
  Minimum Value	0
  Maximum Value	65535

  The port number to use when listening for TCP/IP connections. On Unix and Unix-like systems, the port number must be 1024 or higher unless the server is started by the root operating system user. Setting this option to 0 causes the default value to be used.

• --port-open-timeout=num

  Command-Line Format	--port-open-timeout=#
  Type	Integer
  Default Value	0

  On some systems, when the server is stopped, the TCP/IP port might not become available immediately. If the server is restarted quickly afterward, its attempt to reopen the port can fail. This option indicates how many seconds the server should wait for the TCP/IP port to become free if it cannot be opened. The default is not to wait.

• --print-defaults

  Print the program name and all options that it gets from option files. Password values are masked. This must be the first option on the command line if it is used, except that it may be used immediately after --defaults-file or --defaults-extra-file.

  For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.

• --remove [service_name]

  Command-Line Format	--remove [service_name]
  Platform Specific	Windows

  (Windows only) Remove a MySQL Windows service. The default service name is MySQL if no service_name value is given. For more information, see Section 2.3.4.8, “Starting MySQL as a Windows Service”.

• --safe-user-create

  Command-Line Format	--safe-user-create[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  If this option is enabled, a user cannot create new MySQL users by using the GRANT statement unless the user has the INSERT privilege for the mysql.user system table or any column in the table. If you want a user to have the ability to create new users that have those privileges that the user has the right to grant, you should grant the user the following privilege:

  GRANT INSERT(user) ON mysql.user TO 'user_name'@'host_name';

  This ensures that the user cannot change any privilege columns directly, but has to use the GRANT statement to give privileges to other users.

• --skip-grant-tables

  Command-Line Format	--skip-grant-tables[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  This option affects the server startup sequence:

  • --skip-grant-tables causes the server not to read the grant tables in the mysql system database, and thus to start without using the privilege system at all. This gives anyone with access to the server unrestricted access to all databases.

    To cause a server started with --skip-grant-tables to load the grant tables at runtime, perform a privilege-flushing operation, which can be done in these ways:

    • Issue a MySQL FLUSH PRIVILEGES statement after connecting to the server.

    • Execute a mysqladmin flush-privileges or mysqladmin reload command from the command line.

    Privilege flushing might also occur implicitly as a result of other actions performed after startup, thus causing the server to start using the grant tables. For example, mysql_upgrade flushes the privileges during the upgrade procedure.

  • --skip-grant-tables causes the server not to load certain other objects registered in the mysql system database:

    • Plugins installed using INSTALL PLUGIN and registered in the mysql.plugin system table.

      To cause plugins to be loaded even when using --skip-grant-tables, use the --plugin-load or --plugin-load-add option.

    • Scheduled events installed using CREATE EVENT and registered in the mysql.event system table.

    • Loadable functions installed using CREATE FUNCTION and registered in the mysql.func system table.

  • --skip-grant-tables causes the disabled_storage_engines system variable to have no effect.

• --skip-host-cache

  Command-Line Format	--skip-host-cache

  Disable use of the internal host cache for faster name-to-IP resolution. With the cache disabled, the server performs a DNS lookup every time a client connects.

  Use of --skip-host-cache is similar to setting the host_cache_size system variable to 0, but host_cache_size is more flexible because it can also be used to resize, enable, or disable the host cache at runtime, not just at server startup.

  Starting the server with --skip-host-cache does not prevent runtime changes to the value of host_cache_size, but such changes have no effect and the cache is not re-enabled even if host_cache_size is set larger than 0.

  For more information about how the host cache works, see Section 5.1.11.2, “DNS Lookups and the Host Cache”.

• --skip-innodb

  Disable the InnoDB storage engine. In this case, because the default storage engine is InnoDB, the server cannot start unless you also use --default-storage-engine and --default-tmp-storage-engine to set the default to some other engine for both permanent and TEMPORARY tables.

  The InnoDB storage engine cannot be disabled, and the --skip-innodb option is deprecated and has no effect. Its use results in a warning. Expect this option to be removed in a future release of MySQL.

• --skip-new

  Command-Line Format	--skip-new

  This option disables (what used to be considered) new, possibly unsafe behaviors. It results in these settings: delay_key_write=OFF, concurrent_insert=NEVER, automatic_sp_privileges=OFF. It also causes OPTIMIZE TABLE to be mapped to ALTER TABLE for storage engines for which OPTIMIZE TABLE is not supported.

• --skip-partition

  Command-Line Format	--skip-partition --disable-partition
  Deprecated	5.7.16

  Disables user-defined partitioning. Partitioned tables can be seen using SHOW TABLES or by querying the Information Schema TABLES table, but cannot be created or modified, nor can data in such tables be accessed. All partition-specific columns in the Information Schema PARTITIONS table display NULL.

  Since DROP TABLE removes table definition (.frm) files, this statement works on partitioned tables even when partitioning is disabled using the option. The statement, however, does not remove partition definitions associated with partitioned tables in such cases. For this reason, you should avoid dropping partitioned tables with partitioning disabled, or take action to remove orphaned .par files manually (if present).

  Note

  In MySQL 5.7, partition definition (.par) files are no longer created for partitioned InnoDB tables. Instead, partition definitions are stored in the InnoDB internal data dictionary. Partition definition (.par) files continue to be used for partitioned MyISAM tables.

  This option is deprecated in MySQL 5.7.16, and is removed from MySQL 8.0 because in MySQL 8.0, the partitioning engine is replaced by native partitioning, which cannot be disabled.

• --skip-show-database

  Command-Line Format	--skip-show-database
  System Variable	skip_show_database
  Scope	Global
  Dynamic	No
  Type	Boolean
  Default Value	OFF

  This option sets the skip_show_database system variable that controls who is permitted to use the SHOW DATABASES statement. See Section 5.1.7, “Server System Variables”.

• --skip-stack-trace

  Command-Line Format	--skip-stack-trace

  Do not write stack traces. This option is useful when you are running mysqld under a debugger. On some systems, you also must use this option to get a core file. See Section 5.8, “Debugging MySQL”.

• --slow-start-timeout=timeout

  Command-Line Format	--slow-start-timeout=#
  Type	Integer
  Default Value	15000

  This option controls the Windows service control manager's service start timeout. The value is the maximum number of milliseconds that the service control manager waits before trying to kill the windows service during startup. The default value is 15000 (15 seconds). If the MySQL service takes too long to start, you may need to increase this value. A value of 0 means there is no timeout.

• --socket=path

  Command-Line Format	--socket={file_name|pipe_name}
  System Variable	socket
  Scope	Global
  Dynamic	No
  Type	String
  Default Value (Windows)	MySQL
  Default Value (Other)	/tmp/mysql.sock

  On Unix, this option specifies the Unix socket file to use when listening for local connections. The default value is /tmp/mysql.sock. If this option is given, the server creates the file in the data directory unless an absolute path name is given to specify a different directory. On Windows, the option specifies the pipe name to use when listening for local connections that use a named pipe. The default value is MySQL (not case-sensitive).

• --sql-mode=value[,value[,value...]]

  Command-Line Format	--sql-mode=name
  System Variable	sql_mode
  Scope	Global, Session
  Dynamic	Yes
  Type	Set
  Default Value	ONLY_FULL_GROUP_BY STRICT_TRANS_TABLES NO_ZERO_IN_DATE NO_ZERO_DATE ERROR_FOR_DIVISION_BY_ZERO NO_AUTO_CREATE_USER NO_ENGINE_SUBSTITUTION
  Valid Values	ALLOW_INVALID_DATES ANSI_QUOTES ERROR_FOR_DIVISION_BY_ZERO HIGH_NOT_PRECEDENCE IGNORE_SPACE NO_AUTO_CREATE_USER NO_AUTO_VALUE_ON_ZERO NO_BACKSLASH_ESCAPES NO_DIR_IN_CREATE NO_ENGINE_SUBSTITUTION NO_FIELD_OPTIONS NO_KEY_OPTIONS NO_TABLE_OPTIONS NO_UNSIGNED_SUBTRACTION NO_ZERO_DATE NO_ZERO_IN_DATE ONLY_FULL_GROUP_BY PAD_CHAR_TO_FULL_LENGTH PIPES_AS_CONCAT REAL_AS_FLOAT STRICT_ALL_TABLES STRICT_TRANS_TABLES

  Set the SQL mode. See Section 5.1.10, “Server SQL Modes”.

  Note

  MySQL installation programs may configure the SQL mode during the installation process. If the SQL mode differs from the default or from what you expect, check for a setting in an option file that the server reads at startup.

• --ssl, --skip-ssl

  Command-Line Format	--ssl[={OFF|ON}]
  Disabled by	skip-ssl
  Type	Boolean
  Default Value	ON

  The --ssl option specifies that the server permits but does not require encrypted connections. This option is enabled by default.

  --ssl can be specified in negated form as --skip-ssl or a synonym (--ssl=OFF, --disable-ssl). In this case, the option specifies that the server does not permit encrypted connections, regardless of the settings of the tls_xxx and ssl_xxx system variables.

  For more information about configuring whether the server permits clients to connect using SSL and indicating where to find SSL keys and certificates, see Section 6.3.1, “Configuring MySQL to Use Encrypted Connections”, which also describes server capabilities for certificate and key file autogeneration and autodiscovery. Consider setting at least the ssl_cert and ssl_key system variables on the server side and the --ssl-ca (or --ssl-capath) option on the client side.

• --standalone

  Command-Line Format	--standalone
  Platform Specific	Windows

  Available on Windows only; instructs the MySQL server not to run as a service.

• --super-large-pages

  Command-Line Format	--super-large-pages[={OFF|ON}]
  Platform Specific	Solaris
  Type	Boolean
  Default Value	OFF

  Standard use of large pages in MySQL attempts to use the largest size supported, up to 4MB. Under Solaris, a “super large pages” feature enables uses of pages up to 256MB. This feature is available for recent SPARC platforms. It can be enabled or disabled by using the --super-large-pages or --skip-super-large-pages option.

• --symbolic-links, --skip-symbolic-links

  Command-Line Format	--symbolic-links[={OFF|ON}]
  Type	Boolean
  Default Value	ON

  Enable or disable symbolic link support. On Unix, enabling symbolic links means that you can link a MyISAM index file or data file to another directory with the INDEX DIRECTORY or DATA DIRECTORY option of the CREATE TABLE statement. If you delete or rename the table, the files that its symbolic links point to also are deleted or renamed. See Section 8.12.3.2, “Using Symbolic Links for MyISAM Tables on Unix”.

  This option has no meaning on Windows.

• --sysdate-is-now

  Command-Line Format	--sysdate-is-now[={OFF|ON}]
  Type	Boolean
  Default Value	OFF

  SYSDATE() by default returns the time at which it executes, not the time at which the statement in which it occurs begins executing. This differs from the behavior of NOW(). This option causes SYSDATE() to be a synonym for NOW(). For information about the implications for binary logging and replication, see the description for SYSDATE() in Section 12.7, “Date and Time Functions” and for SET TIMESTAMP in Section 5.1.7, “Server System Variables”.

• --tc-heuristic-recover={COMMIT|ROLLBACK}

  Command-Line Format	--tc-heuristic-recover=name
  Type	Enumeration
  Default Value	OFF
  Valid Values	OFF COMMIT ROLLBACK

  The decision to use in a manual heuristic recovery.

  If a --tc-heuristic-recover option is specified, the server exits regardless of whether manual heuristic recovery is successful.

  On systems with more than one storage engine capable of two-phase commit, the ROLLBACK option is not safe and causes recovery to halt with the following error:

  [ERROR] --tc-heuristic-recover rollback
  strategy is not safe on systems with more than one 2-phase-commit-capable
  storage engine. Aborting crash recovery.

• --temp-pool

  Command-Line Format	--temp-pool[={OFF|ON}]
  Deprecated	5.7.18
  Type	Boolean
  Default Value (Linux)	ON
  Default Value (Other)	OFF

  This option is ignored except on Linux. On Linux, it causes most temporary files created by the server to use a small set of names, rather than a unique name for each new file. This works around a problem in the Linux kernel dealing with creating many new files with different names. With the old behavior, Linux seems to “leak” memory, because it is being allocated to the directory entry cache rather than to the disk cache.

  As of MySQL 5.7.18, this option is deprecated and is removed in MySQL 8.0.

• --transaction-isolation=level

  Command-Line Format	--transaction-isolation=name
  System Variable (≥ 5.7.20)	transaction_isolation
  Scope (≥ 5.7.20)	Global, Session
  Dynamic (≥ 5.7.20)	Yes
  Type	Enumeration
  Default Value	REPEATABLE-READ
  Valid Values	READ-UNCOMMITTED READ-COMMITTED REPEATABLE-READ SERIALIZABLE

  Sets the default transaction isolation level. The level value can be READ-UNCOMMITTED, READ-COMMITTED, REPEATABLE-READ, or SERIALIZABLE. See Section 13.3.6, “SET TRANSACTION Statement”.

  The default transaction isolation level can also be set at runtime using the SET TRANSACTION statement or by setting the tx_isolation (or, as of MySQL 5.7.20, transaction_isolation) system variable.

• --transaction-read-only

  Command-Line Format	--transaction-read-only[={OFF|ON}]
  System Variable (≥ 5.7.20)	transaction_read_only
  Scope (≥ 5.7.20)	Global, Session
  Dynamic (≥ 5.7.20)	Yes
  Type	Boolean
  Default Value	OFF

  Sets the default transaction access mode. By default, read-only mode is disabled, so the mode is read/write.

  To set the default transaction access mode at runtime, use the SET TRANSACTION statement or set the tx_read_only (or, as of MySQL 5.7.20, transaction_read_only) system variable. See Section 13.3.6, “SET TRANSACTION Statement”.

• --tmpdir=dir_name, -t dir_name

  Command-Line Format	--tmpdir=dir_name
  System Variable	tmpdir
  Scope	Global
  Dynamic	No
  Type	Directory name

  The path of the directory to use for creating temporary files. It might be useful if your default /tmp directory resides on a partition that is too small to hold temporary tables. This option accepts several paths that are used in round-robin fashion. Paths should be separated by colon characters (:) on Unix and semicolon characters (;) on Windows.

  --tmpdir can be a non-permanent location, such as a directory on a memory-based file system or a directory that is cleared when the server host restarts. If the MySQL server is acting as a replica, and you are using a non-permanent location for --tmpdir, consider setting a different temporary directory for the replica using the slave_load_tmpdir system variable. For a replication replica, the temporary files used to replicate LOAD DATA statements are stored in this directory, so with a permanent location they can survive machine restarts, although replication can now continue after a restart if the temporary files have been removed.

  For more information about the storage location of temporary files, see Section B.3.3.5, “Where MySQL Stores Temporary Files”.

• --user={user_name|user_id}, -u {user_name|user_id}

  Command-Line Format	--user=name
  Type	String

  Run the mysqld server as the user having the name user_name or the numeric user ID user_id. (“User” in this context refers to a system login account, not a MySQL user listed in the grant tables.)

  This option is mandatory when starting mysqld as root. The server changes its user ID during its startup sequence, causing it to run as that particular user rather than as root. See Section 6.1.1, “Security Guidelines”.

  To avoid a possible security hole where a user adds a --user=root option to a my.cnf file (thus causing the server to run as root), mysqld uses only the first --user option specified and produces a warning if there are multiple --user options. Options in /etc/my.cnf and $MYSQL_HOME/my.cnf are processed before command-line options, so it is recommended that you put a --user option in /etc/my.cnf and specify a value other than root. The option in /etc/my.cnf is found before any other --user options, which ensures that the server runs as a user other than root, and that a warning results if any other --user option is found.

• --validate-user-plugins[={OFF|ON}]

  Command-Line Format	--validate-user-plugins[={OFF|ON}]
  Type	Boolean
  Default Value	ON

  If this option is enabled (the default), the server checks each user account and produces a warning if conditions are found that would make the account unusable:

  • The account requires an authentication plugin that is not loaded.

  • The account requires the sha256_password authentication plugin but the server was started with neither SSL nor RSA enabled as required by this plugin.

  Enabling --validate-user-plugins slows down server initialization and FLUSH PRIVILEGES. If you do not require the additional checking, you can disable this option at startup to avoid the performance decrement.

• --verbose, -v

  Use this option with the --help option for detailed help.

• --version, -V

  Display version information and exit.