Options that affect security: See Section 5.3.3, “Security-Related mysqld Options”.

SSL-related options: See Section 5.5.7.3, “SSL Command Options”.

Binary log control options: See Section 5.2.4, “The Binary Log”.

Replication-related options: See Section 15.1.4, “Replication Options and Variables”.

Options specific to particular storage engines: See Section 13.4.1, “MyISAM Startup Options”, and Section 13.6.4, “InnoDB Startup Options and System Variables”.

--help, -?

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

--abort-slave-event-count

When this option is set to some positive integer value other than 0 (the default) it affects replication behavior as follows: After the slave SQL thread has started, value log events are allowed to be executed; after that, the slave SQL thread does not receive any more events, just as if the network connection from the master were cut. The slave thread continues to run, and the output from SHOW SLAVE STATUS displays Yes in both the Slave_IO_Running and the Slave_SQL_Running columns, but no further events are read from the relay log.

This option is used internally by the MySQL test suite for replication testing and debugging. It is not intended for use in a production setting.

--allow-suspicious-udfs

This option controls whether user-defined functions that have only an xxx symbol for the main function can be loaded. By default, the option is off and only UDFs 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 UDFs. See Section 20.3.2.6, “User-Defined Function Security Precautions”.

--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 1.7.3, “Running MySQL in ANSI Mode”, and Section 5.1.7, “Server SQL Modes”.

--backupdir=path

The path to the default iimage file directory for BACKUP DATABASE and RESTORE operations. If an image file is named as a relative pathname, it is interpreted relative to the value of backupdir. If the value of backupdir is itself a relative pathname, its value is interpreted relative to the data directory. The default value is the data directory. This variable was added in MySQL 6.0.7.

--basedir=path, -b path

The path to the MySQL installation directory. All paths are usually resolved relative to this directory.

--big-tables

Allow large result sets by saving all temporary sets in files. This option prevents most “table full” errors, but also slows down queries for which in-memory tables would suffice. Since MySQL 3.23.2, the server is able to handle large result sets automatically by using memory for small temporary tables and switching to disk tables where necessary.

--bind-address=IP

The IP address to bind to. Only one address can be selected. If this option is specified multiple times, the last address given is used.

--binlog-format={ROW|STATEMENT|MIXED}

Specify whether to use row-based, statement-based, or mixed replication (mixed is the default in MySQL 6.0). See Section 15.1.2, “Replication Formats”.

--binlog-row-event-max-size=N

Specify the maximum size of a row-based binary log event, in bytes. Rows are grouped into events smaller than this size if possible. The value should be a multiple of 256. The default is 1024. See Section 15.1.2, “Replication Formats”.

--bootstrap

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

This option is unavailable if MySQL was configured with the --disable-grant-options option. See Section 2.9.2, “Typical configure Options”.

--character-sets-dir=path

The directory where character sets are installed. See Section 9.2, “The Character Set Used for Data and Sorting”.

--character-set-client-handshake

Don't 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.

--character-set-filesystem=charset_name

The filesystem character set. This option sets the character_set_filesystem system variable.

--character-set-server=charset_name, -C charset_name

Use charset_name as the default server character set. See Section 9.2, “The Character Set Used for Data and Sorting”. If you use this option to specify a non-default character set, you should also use --collation-server to specify the collation.

--chroot=path, -r path

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

--collation-server=collation_name

Use collation_name as the default server collation. See Section 9.2, “The Character Set Used for Data and Sorting”.

--console

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

--core-file

Write a core file if mysqld dies. For some systems, you must also specify the --core-file-size option to mysqld_safe. See Section 4.3.2, “mysqld_safe — MySQL Server Startup Script”. Note that on some systems, such as Solaris, you do not get a core file if you are also using the --user option.

--datadir=path, -h path

The path to the data directory.

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

If MySQL is configured with --with-debug, you can use this option to get a trace file of what mysqld is doing. The debug_options string often is 'd:t:o,file_name'. The default is 'd:t:i:o,mysqld.trace'. See MySQL Internals: Porting.

Using --with-debug 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.

--debug-sync-timeout[=N]

Controls whether the Debug Sync facility for testing and debugging is enabled. Use of Debug Sync requires that MySQL be configured with the ---enable-debug-sync option (see Section 2.9.2, “Typical configure 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.

This option was added in MySQL 6.0.6.

--default-character-set=charset_name (DEPRECATED)

Use charset_name as the default character set. This option is deprecated in favor of --character-set-server. See Section 9.2, “The Character Set Used for Data and Sorting”.

--default-collation=collation_name

Use collation_name as the default collation. This option is deprecated in favor of --collation-server. See Section 9.2, “The Character Set Used for Data and Sorting”.

--default-storage-engine=type

Set the default storage engine (table type) for tables. See Chapter 13, Storage Engines.

--default-table-type=type

This option is a deprecated synonym for --default-storage-engine. It has been removed as of MySQL 6.0.8.

--default-time-zone=timezone

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.

--delay-key-write[={OFF|ON|ALL}]

Specify how to use delayed key writes. Delayed key writing causes key buffers not to be flushed between writes for MyISAM tables. OFF disables delayed key writes. ON enables delayed key writes for those tables that were created with the DELAY_KEY_WRITE option. ALL delays key writes for all MyISAM tables. See Section 7.5.2, “Tuning Server Parameters”, and Section 13.4.1, “MyISAM Startup Options”.

--des-key-file=file_name

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

--disconnect-slave-event-count

This option is used internally by the MySQL test suite for replication testing and debugging.

--enable-named-pipe

Enable support for named pipes. This option applies only on Windows NT, 2000, XP, and 2003 systems.

--enable-pstack

Print a symbolic stack trace on failure.

--engine-condition-pushdown={ON|OFF}

When the value of this option is 0 (OFF), a query such as SELECT * FROM t WHERE mycol = 42, where mycol is a non-indexed column, is executed as a full table scan. The storage engine sends every row to the MySQL server, which applies the WHERE condition. If engine_condition_pushdown is set to 1 (ON), the condition is “pushed down” to the storage engine, which uses the condition to perform the scan, and sends back to the MySQL server only those rows that match the condition. By default, this variable is OFF.

In MySQL 6.0, this option can be used used only with the MyISAM storage engine. It may be implemented for additional storage engines in future MySQL releases.

For more information, see Section 7.2.7, “Condition Pushdown Optimization”.

--event-scheduler[=value]

Enable or disable, and start or stop, the event scheduler.

For detailed information, see The event-scheduler Option.

--exit-info[=flags], -T [flags]

This is a bit mask 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

Enable external locking (system locking), which is disabled by default as of MySQL 4.0. Note that 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. This option previously was named --enable-locking.

For more information about external locking, including conditions under which it can and cannot be used, see Section 7.3.4, “External Locking”.

--flush

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.1.4.2, “What to Do If MySQL Keeps Crashing”.

--gdb

Install an interrupt handler for SIGINT (needed to stop mysqld with ^C to set breakpoints) and disable stack tracing and core file handling. See MySQL Internals: Porting.

--general-log[={0|1}]

Specify the initial general query log state. With no argument or an argument of 1, the --general-log option disables the log. If omitted or given with an argument of 0, the option disables the log.

--init-file=file_name

Read SQL statements from this file at startup. Each statement must be on a single line and should not include comments.

This option is unavailable if MySQL was configured with the --disable-grant-options option. See Section 2.9.2, “Typical configure Options”.

--innodb-xxx

The InnoDB options are listed in Section 13.6.4, “InnoDB Startup Options and System Variables”.

--language=lang_name, -L lang_name

Return client error messages in the given language. lang_name can be given as the language name or as the full pathname to the directory where the language files are installed. See Section 9.3, “Setting the Error Message Language”.

--large-pages

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 OS. Applications that perform a lot of memory accesses may obtain performance improvements by using large pages due to reduced Translation Lookaside Buffer (TLB) misses.

Currently, MySQL supports only the Linux implementation of large pages support (which is called HugeTLB in Linux). We have plans to extend this support to FreeBSD, Solaris and possibly other platforms.

Before large pages can be used on Linux, it is necessary to configure the HugeTLB memory pool. For reference, consult the hugetlbpage.txt file in the Linux kernel source.

This option is disabled by default.

--log[=file_name], -l [file_name]

This option enables logging to the general query log, which contains entries that record client connections and SQL statements received from clients. The log output destination can be selected with the --log-output option. See Section 5.2.1, “Selecting General Query and Slow Query Log Output Destinations”, and Section 5.2.3, “The General Query Log”.

As of MySQL 6.0.8, the --log option is deprecated and will be removed (along with the log system variable) in MySQL 7.0. Instead, use the --general_log option to enable the general query log and the --general_log_file=file_name option to set the general query log filename.

--log-backup-output[=value,...]

This option determines the destination for MySQL Backup history and progress log output. The option value can be given as one or more of the words TABLE, FILE, or NONE. If the option is given without a value, the default is TABLE. TABLE selects logging to the backup_history and backup_progress log tables in the mysql database as a destination. FILE selects logging to log files as a destination. NONE disables logging. If NONE is present in the option value, it takes precedence over any other words that are present. TABLE and FILE can both be given to select to both log output destinations.

This option selects log output destinations, but does not enable log output. To do that, use the --backup_history_log and --backup_progress_log options. For FILE logging, the default log files are backup_history.log and backup_progress.log in the data directory. To change the names, set the global backup_history_log_file and backup_progress_log_file system variables. For more information, see Section 6.3.3.1, “MySQL Backup Log Control”.

This option was added in MySQL 6.0.8.

--log-bin[=base_name]

Enable binary logging. The server logs all statements that change data to the binary log, which is used for backup and replication. See Section 5.2.4, “The Binary Log”.

The option value, if given, is the basename for the log sequence. The server creates binary log files in sequence by adding a numeric suffix to the basename. It is recommended that you specify a basename (see Section B.1.8.1, “Open Issues in MySQL”, for the reason). Otherwise, MySQL uses host_name-bin as the basename.

--log-bin-index[=file_name]

The index file for binary log filenames. See Section 5.2.4, “The Binary Log”. If you omit the filename, and if you didn't specify one with --log-bin, MySQL uses host_name-bin.index as the filename.

--log-bin-trust-function-creators[={0|1}]

With no argument or an argument of 1, this option sets the log_bin_trust_function_creators system variable to 1. With an argument of 0, this option sets the system variable to 0. log_bin_trust_function_creators affects how MySQL enforces restrictions on stored function and trigger creation. See Section 17.6, “Binary Logging of Stored Programs”.

--log-error[=file_name]

Log errors and startup messages to this file. See Section 5.2.2, “The Error Log”. If you omit the filename, MySQL uses host_name.err. If the filename has no extension, the server adds an extension of .err.

--log-isam[=file_name]

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

--log-long-format (DEPRECATED)

Log extra information to the binary log and slow query log, if they have been activated. For example, the username and timestamp are logged for all queries. This option is deprecated, as it now represents the default logging behavior. (See the description for --log-short-format.) The --log-queries-not-using-indexes option is available for the purpose of logging queries that do not use indexes to the slow query log.

--log-output[=value,...]

This option determines the destination for general query log and slow query log output. The option value can be given as one or more of the words TABLE, FILE, or NONE. If the option is given without a value, the default is FILE. TABLE selects logging to the general_log and slow_log tables in the mysql database as a destination. FILE selects logging to log files as a destination. NONE disables logging. If NONE is present in the option value, it takes precedence over any other words that are present. TABLE and FILE can both be given to select to both log output destinations.

This option selects log output destinations, but does not enable log output. To do that, use the --general_log and --slow_query_log options. For FILE logging, the --general_log_file and -slow_query_log_file options determine the log file location. (Before MySQL 6.0.8, enable the logs with the --log and --log-slow-queries options. The options take an optional filename argument to specify the log filename.) For more information, see Section 5.2.1, “Selecting General Query and Slow Query Log Output Destinations”.

--log-queries-not-using-indexes

If you are using this option with the slow query log enabled, queries that are expected to retrieve all rows are logged. See Section 5.2.5, “The Slow Query Log”. This option does not necessarily mean that no index is used. For example, a query that uses a full index scan uses an index but would be logged because the index would not limit the number of rows.

--log-short-format

Log less information to the binary log and slow query log, if they have been activated. For example, the username and timestamp are not logged for queries.

--log-slow-admin-statements

Log slow administrative statements such as OPTIMIZE TABLE, ANALYZE TABLE, and ALTER TABLE to the slow query log.

--log-slow-queries[=file_name]

This option enables logging to the slow query log, which contains entries for all queries that have taken more than long_query_time seconds to execute. See the descriptions of the --log-long-format and --log-short-format options for details.

The log output destination can be selected with the --log-output option. If you omit the filename, MySQL uses host_name-slow.log as the filename. See Section 5.2.1, “Selecting General Query and Slow Query Log Output Destinations”, and Section 5.2.5, “The Slow Query Log”.

As of MySQL 6.0.8, the --log-slow-queries option is deprecated and will be removed (along with the log_slow_queries system variable) in MySQL 7.0. Instead, use the --slow_query_log option to enable the slow query log and the --slow_query_log_file=file_name option to set the slow query log filename.

--log-slow-slave-statements

When the slow query log is enabled, this option enables logging for queries that have taken more than long_query_time seconds to execute on the slave.

This option was added in MySQL 6.0.4.

--log-tc=file_name

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 pathname. Currently, this option is unused.

--log-tc-size=size

The size in bytes of the memory-mapped transaction coordinator log. The default size is 24KB.

--log-warnings[=level], -W [level]

Print out warnings such as Aborted connection... to the error log. Enabling this option is recommended, for example, if you use replication (you get more information about what is happening, such as messages about network failures and reconnections). This option is enabled (1) by default, and the default level value if omitted is 1. To disable this option, use --log-warnings=0. If the value is greater than 1, aborted connections are written to the error log, and access-denied errors for new connection attempts are written. See Section B.1.2.11, “Communication Errors and Aborted Connections”.

If a slave server was started with --log-warnings enabled, the slave prints messages to the error log to provide information about its status, such as the binary log and relay log coordinates where it starts its job, when it is switching to another relay log, when it reconnects after a disconnect, and so forth.

--low-priority-updates

Give table-modifying operations (INSERT, REPLACE, DELETE, UPDATE) lower priority than selects. This can also be done via {INSERT | REPLACE | DELETE | UPDATE} LOW_PRIORITY ... to lower the priority of only one query, or by SET LOW_PRIORITY_UPDATES=1 to change the priority in one thread. This affects only storage engines that use only table-level locking (MyISAM, MEMORY, MERGE). See Section 7.3.2, “Table Locking Issues”.

--min-examined-row-limit=number

When this option is set, queries which examine fewer than number rows are not written to the slow query log. The default is 0.

This option was introduced in MySQL 6.0.4.

--max-binlog-dump-events

This option is used internally by the MySQL test suite for replication testing and debugging.

--memlock

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 as well as most Linux distributions that use a 2.4 or newer kernel. 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:

shell> 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;

--myisam_block_size=size

The block size to be used for MyISAM index pages.

--myisam-recover[=option[,option]...]]

Set the MyISAM storage engine recovery mode. The option value is any combination of the values of DEFAULT, BACKUP, FORCE, or QUICK. If you specify multiple values, separate them by commas. Specifying the option with no argument is the same as specifying DEFAULT, and specifying with an explicit value of "" disables recovery (same as not giving the option). If recovery is enabled, each time mysqld opens a MyISAM table, it checks whether the table is marked as crashed or wasn't closed properly. (The last option works only if you are running with external locking disabled.) If this is the case, mysqld runs a check on the table. If the table was corrupted, mysqld attempts to repair it.

The following options affect how the repair works:

Before the server automatically repairs a table, it writes a note about the repair to the error log. If you want to be able to recover from most problems without user intervention, you should use the options BACKUP,FORCE. This forces a repair of a table even if some rows would be deleted, but it keeps the old data file as a backup so that you can later examine what happened.

See Section 13.4.1, “MyISAM Startup Options”.

--old-passwords

Force the server to generate short (pre-4.1) password hashes for new passwords. This is useful for compatibility when the server must support older client programs. See Section 5.4.8, “Password Hashing as of MySQL 4.1”.

--old-style-user-limits

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 5.5.4, “Limiting Account Resources”.

--one-thread

Only use one thread (for debugging under Linux). This option is available only if the server is built with debugging enabled. See MySQL Internals: Porting.

This option is deprecated; use --thread_handling=one-thread instead.

--open-files-limit=count

Changes the number of file descriptors available to mysqld. You should try increasing the value of this option if mysqld gives you the error Too many open files. mysqld uses the option value to reserve descriptors with setrlimit(). If the requested number of file descriptors cannot be allocated, mysqld writes a warning to the error log.

mysqld may attempt to allocate more than the requested number of descriptors (if they are available), using the values of max_connections and table_open_cache to estimate whether more descriptors will be needed.

--pid-file=path

The pathname of the process ID file. This file is used by other programs such as mysqld_safe to determine the server's process ID.

--plugin-load=plugin_list

Under normal startup, the server determines which plugins to load by reading the mysql.plugins system table. This option enables plugins to be loaded even when --skip-grant-tables is given (which tells the server not to read system tables). This option also enables plugins to be loaded at startup under configurations when plugins cannot be loaded at runtime.

The option value is a colon-separated list of name=plugin_library values. Each name is the name of the plugin, and plugin_library is the name of the shared library that contains the plugin code. Each library file must be located in the directory named by the plugin_dir system variable. For example, if plugins named myplug1 and myplug2 have library files myplug1.so and myplug2.so, use this option to load them at startup:

shell> mysqld --plugin-load=myplug1=myplug1.so:myplug2=myplug2.so

All plugins to load must be named in the same --plugin-load option. If multiple --plugin-load options are given, only the last one is used.

The plugins are loaded for a single invocation of mysqld only. After a restart, the plugins are 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.

--port=port_num, -P port_num

The port number to use when listening for TCP/IP connections