Options that affect security: See Section 5.6.3, Security-Related mysqld Options.

SSL-related options: See Section 5.8.7.3, SSL Command Options.

Binary log control options: See Section 5.11.4, The Binary Log.

Replication-related options: See Section 6.8, Replication Startup Options.

Options specific to particular storage engines: See Section 14.1.1, MyISAM Startup Options, Section 14.5.3, BDB Startup Options, Section 14.2.5, InnoDB Startup Options and System Variables, and Section 15.6.5.1, MySQL Cluster-Related Command Options for mysqld.

--help, -?

Display a short help message and exit. Before MySQL 4.1.1, --help displays the full help message. As of 4.1.1, it displays an abbreviated message only. Use both the --verbose and --help options to see the full message.

--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. This option was added in MySQL 4.0.24, and 4.1.10a. See Section 19.2.4.6, 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 1.9.3, Running MySQL in ANSI Mode, and Section 5.2.5, SQL Modes.

--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.

--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.

--character-sets-dir=path

The directory where character sets are installed. See Section 5.10.1, 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 4.1 and higher behave like MySQL 4.0. This option was added in MySQL 4.1.15.

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

Use charset_name as the default server character set. See Section 5.10.1, 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. This option is available as of MySQL 4.1.3.

--chroot=path

Put the mysqld server in a closed environment during startup by using the chroot() system call. This is a recommended security measure as of MySQL 4.0. (MySQL 3.23 is not able to provide a chroot() jail that is 100% closed.) 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. This option is available as of MySQL 4.1.3. See Section 5.10.1, 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 5.4.1, 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 Section E.1.2, Creating Trace Files.

--default-character-set=charset_name, -C charset_name

Use charset_name as the default character set. This option is deprecated in favor of --character-set-server as of MySQL 4.1.3. See Section 5.10.1, 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 as of MySQL 4.1.3. See Section 5.10.1, The Character Set Used for Data and Sorting.

--default-storage-engine=type

This option is a synonym for --default-table-type. It is available as of MySQL 4.1.2.

--default-table-type=type

Set the default table type (storage engine) for tables. See Chapter 14, Storage Engines and Table Types.

--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. This option is available as of MySQL 4.1.3.

--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. Available as of MySQL 4.0.3. See Section 7.5.2, Tuning Server Parameters, and Section 14.1.1, MyISAM Startup Options.

Note: If you set this variable to ALL, you should not use MyISAM tables from within another program (such as another MySQL server or myisamchk) when the tables are in use. Doing so leads to index corruption.

--delay-key-write-for-all-tables

Old form of --delay-key-write=ALL for use prior to MySQL 4.0.3. As of 4.0.3, use --delay-key-write instead.

--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.

--enable-named-pipe

Enable support for named pipes. This option applies only on Windows NT, 2000, XP, and 2003 systems, and can be used only with the mysqld-nt and mysqld-max-nt servers that support named-pipe connections.

--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 was named --enable-locking before MySQL 4.0.3.

Note: If you use this option to enable updates to MyISAM tables from many MySQL processes, you must ensure that the following conditions are satisfied:

The easiest way to ensure this is to always use --external-locking together with --delay-key-write=OFF and --query-cache-size=0. (This is not done by default because in many setups it is useful to have a mixture of the preceding options.)

--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 A.4.2, What to Do If MySQL Keeps Crashing.

--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.

--innodb-safe-binlog

Adds consistency guarantees between the content of InnoDB tables and the binary log. See Section 5.11.4, The Binary Log.

--innodb-xxx

The InnoDB options are listed in Section 14.2.5, 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 5.10.2, Setting the Error Message Language.

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

Log connections and SQL statements received from clients to this file. See Section 5.11.2, The General Query Log. If you omit the filename, MySQL uses host_name.log as the filename.

--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 5.11.4, 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 A.8.4, 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 5.11.4, 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-error[=file_name]

Log errors and startup messages to this file. See Section 5.11.1, 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 ISAM/MyISAM changes to this file (used only when debugging ISAM/MyISAM).

--log-long-format

Log extra information to the update log, binary update log, and slow query log, if they have been activated. For example, the username and timestamp are logged for queries. Before MySQL 4.1, if you are using --log-slow-queries and --log-long-format, queries that are not using indexes also are logged to the slow query log. --log-long-format is deprecated as of MySQL version 4.1, when --log-short-format was introduced. (Long log format is the default setting since version 4.1.) Also note that starting with MySQL 4.1, 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-queries-not-using-indexes

If you are using this option with --log-slow-queries, queries that do not use indexes also are logged to the slow query log. This option is available as of MySQL 4.1. See Section 5.11.5, The Slow Query Log.

--log-short-format

Log less information to the update log, binary update log, and slow query log, if they have been activated. For example, the username and timestamp are not logged for queries. This option was introduced in MySQL 4.1.

--log-slow-admin-statements

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

This option was added in MySQL 4.1.13. (It is unnecessary in MySQL 4.0 because slow administrative statements are logged by default.)

--log-slow-queries[=file_name]

Log all queries that have taken more than long_query_time seconds to execute to this file. See Section 5.11.5, The Slow Query Log. Note that the default for the amount of information logged has changed in MySQL 4.1. See the --log-long-format and --log-short-format options for details.

--log-update[=file_name]

Log updates to fileN where N is a unique number if not given. See Section 5.11.3, The Update Log. The update log is now deprecated; you should use the binary log instead (--log-bin). See Section 5.11.4, The Binary Log.

--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 by default as of MySQL 4.0.19 and 4.1.2; to disable it, use --log-warnings=0. As of MySQL 4.0.21 and 4.1.3, a level argument can be given. If omitted, the default level is 1. Aborted connections are not logged to the error log unless the value is greater than 1. See Section A.2.10, Communication Errors and Aborted Connections.

Before MySQL 4.0.21 and 4.1.3, this is a boolean option, not an integer-valued option. Before 4.0, this option was named --warnings.

--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. See Section 7.3.2, Table Locking Issues.

--memlock

Lock the mysqld process in memory. This works on systems such as Solaris that support the mlockall() system call. This might help if you have a problem where the operating system is causing mysqld to swap on disk. Note that use of this option requires that you run the server as root, which is normally not a good idea for security reasons. See Section 5.6.5, How to Run MySQL as a Normal User.

--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. You can also use a value of "" to disable this option. If this option is used, 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.

This option is available as of MySQL 3.23.25.

--ndb-connectstring=connect_string

When using the NDB storage engine, it is possible to point out the management server that distributes the cluster configuration by setting the connect string option. See Section 15.4.4.2, The Cluster connectstring, for syntax.

--ndbcluster

If the binary includes support for the NDB Cluster storage engine (from version 4.1.3, the MySQL-Max binaries are built with NDB Cluster enabled), this option enables the engine, which is disabled by default. Using the NDB Cluster storage engine is necessary for using MySQL Cluster. See Chapter 15, MySQL Cluster.

--new

The --new option can be used to make the server behave as 4.1 in certain respects, easing a 4.0 to 4.1 upgrade:

This option can be used to help you see how your applications behave in MySQL 4.1, without actually upgrading to 4.1.

--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 5.7.9, Password Hashing as of MySQL 4.1.

--old-protocol, -o

Use the 3.20 protocol for compatibility with some very old clients.

--one-thread

Only use one thread (for debugging under Linux). This option is available only if the server is built with debugging enabled. See Section E.1, Debugging a MySQL Server.

--open-files-limit=count

Change the number of file descriptors available to mysqld. If this option is not set or is set to 0, mysqld uses the value to reserve file descriptors with setrlimit(). If the value is 0, mysqld reserves max_connections×5 or max_connections + table_open_cache×2 files (whichever is larger). You should try increasing this value if mysqld gives you the error Too many open files.

--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.

--port=port_num, -P port_num

The port number to use when listening for TCP/IP connections. The port number must be 1024 or higher unless the server is started by the root system user.

--safe-mode

Skip some optimization stages.

--safe-show-database

With this option, the SHOW DATABASES statement displays only the names of those databases for which the user has some kind of privilege. As of MySQL 4.0.2, this option is deprecated and does not do anything (it is enabled by default), because there is a SHOW DATABASES privilege that can be used to control access to database names on a per-account basis. See Section 5.7.3, Privileges Provided by MySQL.

--safe-user-create

If this option is enabled, a user cannot create new MySQL users by using the GRANT statement, if the user doesn't have the INSERT privilege for the mysql.user table or any column in the table.

--secure-auth

Disallow authentication by clients that attempt to use accounts that have old (pre-4.1) passwords. This option is available as of MySQL 4.1.1.

--shared-memory

Enable shared-memory connections by local clients. This option is available only on Windows. It was added in MySQL 4.1.0.

--shared-memory-base-name=name

The name of shared memory to use for shared-memory connections. This option is available only on Windows. The default name is MYSQL. The name is case sensitive. This option was added in MySQL 4.1.0.

--skip-bdb

Disable the BDB storage engine. This saves memory and might speed up some operations. Do not use this option if you require BDB tables.

--skip-concurrent-insert

Turn off the ability to select and insert at the same time on MyISAM tables. (This is to be used only if you think you have found a bug in this feature.) See Section 7.3.3, Concurrent Inserts.

--skip-delay-key-write

Ignore the DELAY_KEY_WRITE option for all tables. As of MySQL 4.0.3, you should use --delay-key-write=OFF instead. See Section 7.5.2, Tuning Server Parameters.

--skip-external-locking

Do not use external locking (system locking). With external locking disabled, you must shut down the server to use myisamchk or isamchk. See Section 1.4.3, MySQL Stability. As of MySQL 3.23, you can use the CHECK TABLE and REPAIR TABLE statements to check and repair MyISAM tables. This option previously was named --skip-locking.

External locking has been disabled by default since MySQL 4.0.

--skip-grant-tables

This option causes the server not to use the privilege system at all, which gives anyone with access to the server unrestricted access to all databases. You can cause a running server to start using the grant tables again by executing mysqladmin flush-privileges or mysqladmin reload command from a system shell, or by issuing a MySQL FLUSH PRIVILEGES statement after connecting to the server. This option also suppresses loading of user-defined functions (UDFs).

--skip-host-cache

Do not use the internal hostname cache for faster name-to-IP resolution. Instead, query the DNS server every time a client connects. See Section 7.5.5, How MySQL Uses DNS.

--skip-innodb

Disable the InnoDB storage engine. This saves memory and disk space and might speed up some operations. Do not use this option if you require InnoDB tables.

--skip-isam

Disable the ISAM storage engine. As of MySQL 4.1, ISAM is disabled by default, so this option applies only if the server was configured with support for ISAM. This option was added in MySQL 4.1.1.

--skip-merge

Disable the MERGE storage engine. This option was added in MySQL 4.1.21. It can be used if the following behavior is undesirable: If a user has access to MyISAM table t, that user can create a MERGE table m that accesses t. However, if the user's privileges on t are subsequently revoked, the user can continue to access t by doing so through m.

--skip-name-resolve

Do not resolve hostnames when checking client connections. Use only IP numbers. If you use this option, all Host column values in the grant tables must be IP numbers or localhost. See Section 7.5.5, How MySQL Uses DNS.

--skip-ndbcluster

Disable the NDB Cluster storage engine. This is the default for binaries that were built with NDB Cluster storage engine support; the server allocates memory and other resources for this storage engine only if the --ndbcluster option is given explicitly. See Section 15.4.3, Quick Test Setup of MySQL Cluster, for an example of usage.

--skip-networking

Do not listen for TCP/IP connections at all. All interaction with mysqld must be made via named pipes or shared memory (on Windows) or Unix socket files (on Unix). This option is highly recommended for systems where only local clients are allowed. See Section 7.5.5, How MySQL Uses DNS.

--skip-new

do not use new, possibly wrong routines.

--skip-symlink

This is the old form of --skip-symbolic-links, for use before MySQL 4.0.13.

--ssl*

Options that begin with --ssl specify whether to allow clients to connect via SSL and indicate where to find SSL keys and certificates. See Section 5.8.7.3, SSL Command Options.

--standalone

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

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

Enable or disable symbolic link support. This option has different effects on Windows and Unix:

This option was added in MySQL 4.0.13.

--skip-safemalloc

If MySQL is configured with --with-debug=full, all MySQL programs check for memory overruns during each memory allocation and memory freeing operation. This checking is very slow, so for the server you can avoid it when you do not need it by using the --skip-safemalloc option.

--skip-show-database

With this option, the SHOW DATABASES statement is allowed only to users who have the SHOW DATABASES privilege, and the statement displays all database names. Without this option, SHOW DATABASES is allowed to all users, but displays each database name only if the user has the SHOW DATABASES privilege or some privilege for the database. Note that any global privilege is considered a privilege for the database.

--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 E.1, Debugging a MySQL Server.

--skip-thread-priority

Disable using thread priorities for faster response time.

--socket=path

On Unix, this option specifies the Unix socket file to use when listening for local connections. The default value is /tmp/mysql.sock. 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...]]

Set the SQL mode. See Section 5.2.5, SQL Modes. This option was added in 3.23.41.

--temp-pool

This option 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.

--transaction-isolation=level

Sets the default transaction isolation level. The level value can be READ-UNCOMMITTED, READ-COMMITTED, REPEATABLE-READ, or SERIALIZABLE. See Section 13.4.6, SET TRANSACTION Syntax.

--tmpdir=path, -t path

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. Starting from MySQL 4.1.0, 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, NetWare, and OS/2. If the MySQL server is acting as a replication slave, you should not set --tmpdir to point to a directory on a memory-based filesystem or to a directory that is cleared when the server host restarts. For more information about the storage location of temporary files, see Section A.4.4, Where MySQL Stores Temporary Files. A replication slave needs some of its temporary files to survive a machine restart so that it can replicate temporary tables or LOAD DATA INFILE operations. If files in the temporary file directory are lost when the server restarts, replication fails.

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

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 5.6.1, General Security Guidelines.

Starting from MySQL 3.23.56 and 4.0.12: 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.

--version, -V

Display version information and exit.

To see the values that a server will use based on its compiled-in defaults and any option files that it reads, use this command (omit --verbose before MySQL 4.1.1):

mysqld --verbose --help

To see the values that a server will use based on its compiled-in defaults, ignoring the settings in any option files, use this command (omit --verbose before MySQL 4.1.1):

mysqld --no-defaults --verbose --help

To see the current values used by a running server, use the SHOW VARIABLES statement.

Section 5.2.3, Using System Variables, discusses the syntax for setting and displaying system variable values.

Section 5.2.3.2, Dynamic System Variables, lists the variables that can be set at runtime.

Information on tuning sytem variables can be found in Section 7.5.2, Tuning Server Parameters.

Section 14.2.5, InnoDB Startup Options and System Variables, lists InnoDB system variables.

ansi_mode

This is ON if mysqld was started with --ansi. See Section 1.9.3, Running MySQL in ANSI Mode. This variable was added in MySQL 3.23.6 and removed in 3.23.41. See the description for sql_mode.

back_log

The number of outstanding connection requests MySQL can have. This comes into play when the main MySQL thread gets very many connection requests in a very short time. It then takes some time (although very little) for the main thread to check the connection and start a new thread. The back_log value indicates how many requests can be stacked during this short time before MySQL momentarily stops answering new requests. You need to increase this only if you expect a large number of connections in a short period of time.

In other words, this value is the size of the listen queue for incoming TCP/IP connections. Your operating system has its own limit on the size of this queue. The manual page for the Unix listen() system call should have more details. Check your OS documentation for the maximum value for this variable. back_log cannot be set higher than your operating system limit.

basedir

The MySQL installation base directory. This variable can be set with the --basedir option.

bdb_cache_size

The size of the buffer that is allocated for caching indexes and rows for BDB tables. If you do not use BDB tables, you should start mysqld with --skip-bdb to not allocate memory for this cache. This variable was added in MySQL 3.23.14.

bdb_home

The base directory for BDB tables. This should be assigned the same value as the datadir variable. This variable was added in MySQL 3.23.14.

bdb_log_buffer_size

The size of the buffer that is allocated for caching indexes and rows for BDB tables. If you do not use BDB tables, you should set this to 0 or start mysqld with --skip-bdb in order not to allocate memory for this cache. This variable was added in MySQL 3.23.31.

bdb_logdir

The directory where the BDB storage engine writes its log files. This variable can be set with the --bdb-logdir option. This variable was added in MySQL 3.23.14.

bdb_max_lock

The maximum number of locks that can be active for a BDB table (10,000 by default). You should increase this value if errors such as the following occur when you perform long transactions or when mysqld has to examine many rows to calculate a query:

bdb: Lock table is out of available locks
Got error 12 from ...

This variable was added in MySQL 3.23.29.

bdb_shared_data

This is ON if you are using --bdb-shared-data to start Berkeley DB in multi-process mode. (Do not use DB_PRIVATE when initializing Berkeley DB.) This variable was added in MySQL 3.23.29.

bdb_tmpdir

The BDB temporary file directory. This variable was added in MySQL 3.23.14.

bdb_version

See the description for version_bdb.

binlog_cache_size

The size of the cache to hold the SQL statements for the binary log during a transaction. A binary log cache is allocated for each client if the server supports any transactional storage engines and, starting from MySQL 4.1.2, if the server has the binary log enabled (--log-bin option). If you often use large, multiple-statement transactions, you can increase this cache size to get more performance. The Binlog_cache_use and Binlog_cache_disk_use status variables can be useful for tuning the size of this variable. This variable was added in MySQL 3.23.29. See Section 5.11.4, The Binary Log.

bulk_insert_buffer_size

MyISAM uses a special tree-like cache to make bulk inserts faster for INSERT ... SELECT, INSERT ... VALUES (...), (...), ..., and LOAD DATA INFILE when adding data to non-empty tables. This variable limits the size of the cache tree in bytes per thread. Setting it to 0 disables this optimization. The default value is 8MB. This variable was added in MySQL 4.0.3. This variable previously was named myisam_bulk_insert_tree_size.

character_set

The default character set. This variable was added in MySQL 3.23.3, then removed in MySQL 4.1.1 and replaced by the various character_set_xxx variables.

character_set_client

The character set for statements that arrive from the client. This variable was added in MySQL 4.1.1.

character_set_connection

The character set used for literals that do not have a character set introducer and for number-to-string conversion. This variable was added in MySQL 4.1.1.

character_set_database

The character set used by the default database. The server sets this variable whenever the default database changes. If there is no default database, the variable has the same value as character_set_server. This variable was added in MySQL 4.1.1.

character_set_results

The character set used for returning query results to the client. This variable was added in MySQL 4.1.1.

character_set_server

The server default character set. This variable was added in MySQL 4.1.1.

character_set_system

The character set used by the server for storing identifiers. The value is always utf8. This variable was added in MySQL 4.1.1.

character_sets

The supported character sets. This variable was added in MySQL 3.23.15 and removed in MySQL 4.1.1. (Use SHOW CHARACTER SET for a list of character sets.)

character_sets_dir

The directory where character sets are installed. This variable was added in MySQL 4.1.2.

collation_connection

The collation of the connection character set. This variable was added in MySQL 4.1.1.

collation_database

The collation used by the default database. The server sets this variable whenever the default database changes. If there is no default database, the variable has the same value as collation_server. This variable was added in MySQL 4.1.1.

collation_server

The server default collation. This variable was added in MySQL 4.1.1.

concurrent_insert

If ON (the default), MySQL allows INSERT and SELECT statements to run concurrently for MyISAM tables that have no free blocks in the middle. You can turn this option off by starting mysqld with --safe or --skip-new. This variable was added in MySQL 3.23.7.

See also Section 7.3.3, Concurrent Inserts.

connect_timeout

The number of seconds that the mysqld server waits for a connect packet before responding with Bad handshake.

convert_character_set

The current character set mapping that was set by SET CHARACTER SET. This variable was removed in MySQL 4.1.

datadir

The MySQL data directory. This variable can be set with the --datadir option.

date_format

This variable is not implemented.

datetime_format

This variable is not implemented.

default_week_format

The default mode value to use for the WEEK() function. See Section 12.5, Date and Time Functions. This variable is available as of MySQL 4.0.14.

delay_key_write

This option applies only to MyISAM tables. It can have one of the following values to affect handling of the DELAY_KEY_WRITE table option that can be used in CREATE TABLE statements.

If DELAY_KEY_WRITE is enabled for a table, the key buffer is not flushed for the table on every index update, but only when the table is closed. This speeds up writes on keys a lot, but if you use this feature, you should add automatic checking of all MyISAM tables by starting the server with the --myisam-recover option (for example, --myisam-recover=BACKUP,FORCE). See Section 5.2.1, Command Options, and Section 14.1.1, MyISAM Startup Options.

Note that enabling external locking with --external-locking offers no protection against index corruption for tables that use delayed key writes.

This variable was added in MySQL 3.23.8.

delayed_insert_limit

After inserting delayed_insert_limit delayed rows, the INSERT DELAYED handler thread checks whether there are any SELECT statements pending. If so, it allows them to execute before continuing to insert delayed rows.

delayed_insert_timeout

How many seconds an INSERT DELAYED handler thread should wait for INSERT statements before terminating.

delayed_queue_size

This is a per-table limit on the number of rows to queue when handling INSERT DELAYED statements. If the queue becomes full, any client that issues an INSERT DELAYED statement waits until there is room in the queue again.

expire_logs_days

The number of days for automatic binary log removal. The default is 0, which means no automatic removal. Possible removals happen at startup and at binary log rotation. This variable was added in MySQL 4.1.0.

flush

If ON, the server flushes (synchronizes) 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 A.4.2, What to Do If MySQL Keeps Crashing. This variable is set to ON if you start mysqld with the --flush option. This variable was added in MySQL 3.22.9.

flush_time

If this is set to a non-zero value, all tables are closed every flush_time seconds to free up resources and synchronize unflushed data to disk. We recommend that this option be used only on Windows 9x or Me, or on systems with minimal resources. This variable was added in MySQL 3.22.18.

ft_boolean_syntax

The list of operators supported by boolean full-text searches performed using IN BOOLEAN MODE. See Section 12.7.1, Boolean Full-Text Searches. This variable was added as a read-only variable in MySQL 4.0.1. It can be modified as of MySQL 4.1.2.

The default variable value is '+ -><()~*:""&|'. The rules for changing the value are as follows:

ft_max_word_len

The maximum length of the word to be included in a FULLTEXT index. This variable was added in MySQL 4.0.0.

Note: FULLTEXT indexes must be rebuilt after changing this variable. Use REPAIR TABLE tbl_name QUICK.

ft_min_word_len

The minimum length of the word to be included in a FULLTEXT index. This variable was added in MySQL 4.0.0.

Note: FULLTEXT indexes must be rebuilt after changing this variable. Use REPAIR TABLE tbl_name QUICK.

ft_query_expansion_limit

The number of top matches to use for full-text searches performed using WITH QUERY EXPANSION. This variable was added in MySQL 4.1.1.

ft_stopword_file

The file from which to read the list of stopwords for full-text searches. All the words from the file are used; comments are not honored. By default, a built-in list of stopwords is used (as defined in the myisam/ft_static.c file). Setting this variable to the empty string ('') disables stopword filtering. This variable was added in MySQL 4.0.10.

Note: FULLTEXT indexes must be rebuilt after changing this variable or the contents of the stopword file. Use REPAIR TABLE tbl_name QUICK.

group_concat_max_len

The maximum allowed result length for the GROUP_CONCAT() function. The default is 1024. This variable was added in MySQL 4.1.0.

have_archive

YES if mysqld supports ARCHIVE tables, NO if not. This variable was added in MySQL 4.1.3.

have_bdb

YES if mysqld supports BDB tables. DISABLED if --skip-bdb is used. This variable was added in MySQL 3.23.30.

have_blackhole_engine

YES if mysqld supports BLACKHOLE tables, NO if not. This variable was added in MySQL 4.1.11.

have_compress

YES if the zlib compression library is available to the server, NO if not. If not, the COMPRESS() and UNCOMPRESS() functions cannot be used. This variable was added in MySQL 4.1.1.

have_crypt

YES if the crypt() system call is available to the server, NO if not. If not, the ENCRYPT() function cannot be used. This variable was added in MySQL 4.0.10.

have_csv

YES if mysqld supports ARCHIVE tables, NO if not. This variable was added in MySQL 4.1.4.

have_example_engine

YES if mysqld supports EXAMPLE tables, NO if not. This variable was added in MySQL 4.1.4.

have_geometry

YES if the server supports spatial data types, NO if not. This variable was added in MySQL 4.1.3.

have_innodb

YES if mysqld supports InnoDB tables. DISABLED if --skip-innodb is used. This variable was