--help

Display a help message and exit.

--basedir=dir_name

The path to the MySQL installation directory.

--core-file-size=size

The size of the core file that mysqld should be able to create. The option value is passed to ulimit -c.

--datadir=dir_name

The path to the data directory.

--defaults-extra-file=file_name

Read this option file in addition to the usual option files. If the file does not exist or is otherwise inaccessible, the server will exit with an error. file_name is interpreted relative to the current directory if given as a relative path name rather than a full path name. 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 4.2.8, “Command-Line Options that Affect Option-File Handling”.

--defaults-file=file_name

Use only the given option file. If the file does not exist or is otherwise inaccessible, the server will exit with an error. file_name is interpreted relative to the current directory if given as a relative path name rather than a full path name. 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 4.2.8, “Command-Line Options that Affect Option-File Handling”.

--ledir=dir_name

If mysqld_safe cannot find the server, use this option to indicate the path name to the directory where the server is located.

This option is accepted only on the command line, not in option files. On platforms that use systemd, the value can be specified in the value of MYSQLD_OPTS. See Section 2.5.9, “Managing MySQL Server with systemd”.

--log-error=file_name

Write the error log to the given file. See Section 5.4.2, “The Error Log”.

--mysqld-safe-log-timestamps

This option controls the format for timestamps in log output produced by mysqld_safe. The following list describes the permitted values. For any other value, mysqld_safe logs a warning and uses UTC format.

--malloc-lib=[lib_name]

The name of the library to use for memory allocation instead of the system malloc() library. The option value must be one of the directories /usr/lib, /usr/lib64, /usr/lib/i386-linux-gnu, or /usr/lib/x86_64-linux-gnu.

The --malloc-lib option works by modifying the LD_PRELOAD environment value to affect dynamic linking to enable the loader to find the memory-allocation library when mysqld runs:

Linux users can use the libtcmalloc_minimal.so library on any platform for which a tcmalloc package is installed in /usr/lib by adding these lines to the my.cnf file:

[mysqld_safe]
malloc-lib=tcmalloc

To use a specific tcmalloc library, specify its full path name. Example:

[mysqld_safe]
malloc-lib=/opt/lib/libtcmalloc_minimal.so

--mysqld=prog_name

The name of the server program (in the ledir directory) that you want to start. This option is needed if you use the MySQL binary distribution but have the data directory outside of the binary distribution. If mysqld_safe cannot find the server, use the --ledir option to indicate the path name to the directory where the server is located.

This option is accepted only on the command line, not in option files. On platforms that use systemd, the value can be specified in the value of MYSQLD_OPTS. See Section 2.5.9, “Managing MySQL Server with systemd”.

--mysqld-version=suffix

This option is similar to the --mysqld option, but you specify only the suffix for the server program name. The base name is assumed to be mysqld. For example, if you use --mysqld-version=debug, mysqld_safe starts the mysqld-debug program in the ledir directory. If the argument to --mysqld-version is empty, mysqld_safe uses mysqld in the ledir directory.

This option is accepted only on the command line, not in option files. On platforms that use systemd, the value can be specified in the value of MYSQLD_OPTS. See Section 2.5.9, “Managing MySQL Server with systemd”.

--nice=priority

Use the nice program to set the server's scheduling priority to the given value.

--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 4.2.8, “Command-Line Options that Affect Option-File Handling”.

--open-files-limit=count

The number of files that mysqld should be able to open. The option value is passed to ulimit -n.

--pid-file=file_name

The path name that mysqld should use for its process ID file.

--plugin-dir=dir_name

The path name of the plugin directory.

--port=port_num

The port number that the server should 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.

--skip-kill-mysqld

Do not try to kill stray mysqld processes at startup. This option works only on Linux.

--socket=path

The Unix socket file that the server should use when listening for local connections.

--syslog, --skip-syslog

--syslog causes error messages to be sent to syslog on systems that support the logger program. --skip-syslog suppresses the use of syslog; messages are written to an error log file.

When syslog is used for error logging, the daemon.err facility/severity is used for all log messages.

Using these options to control mysqld logging is deprecated. To write error log output to the system log, use the instructions at Section 5.4.2.3, “Error Logging to the System Log”. To control the facility, use the server log_syslog_facility system variable.

--syslog-tag=tag

For logging to syslog, messages from mysqld_safe and mysqld are written with identifiers of mysqld_safe and mysqld, respectively. To specify a suffix for the identifiers, use --syslog-tag=tag, which modifies the identifiers to be mysqld_safe-tag and mysqld-tag.

Using this option to control mysqld logging is deprecated. Use the server log_syslog_tag system variable instead. See Section 5.4.2.3, “Error Logging to the System Log”.

--timezone=timezone

Set the TZ time zone environment variable to the given option value. Consult your operating system documentation for legal time zone specification formats.

--user={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.)

The server and databases can be found relative to the working directory (the directory from which mysqld_safe is invoked). For binary distributions, mysqld_safe looks under its working directory for bin and data directories. For source distributions, it looks for libexec and var directories. This condition should be met if you execute mysqld_safe from your MySQL installation directory (for example, /usr/local/mysql for a binary distribution).

If the server and databases cannot be found relative to the working directory, mysqld_safe attempts to locate them by absolute path names. Typical locations are /usr/local/libexec and /usr/local/var. The actual locations are determined from the values configured into the distribution at the time it was built. They should be correct if MySQL is installed in the location specified at configuration time.

--log-error=file_name: Write error messages to the named error file.

--syslog: Write error messages to syslog on systems that support the logger program.

--skip-syslog: Do not write error messages to syslog. Messages are written to the default error log file (host_name.err in the data directory), or to a named file if the --log-error option is given.