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For some Linux platforms, MySQL installation from RPM or Debian packages includes systemd support for managing MySQL server startup and shutdown. On these platforms,mysqld_safe is not installed because it is unnecessary. For more information, seeSection 2.5.9, “Managing MySQL Server with systemd”.

One implication of the non-use ofmysqld_safe on platforms that use systemd for server management is that use of[mysqld_safe] or[safe_mysqld] sections in option files is not supported and might lead to unexpected behavior.

Table 6.7 mysqld_safe Options

• --help

  Command-Line Format	--help

  Display a help message and exit.

• --basedir=dir_name

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

  The path to the MySQL installation directory.

• --core-file-size=size

  Command-Line Format	--core-file-size=size
  Type	String

  The size of the core file thatmysqld should be able to create. The option value is passed toulimit -c.

  Note

  Theinnodb_buffer_pool_in_core_file variable can be used to reduce the size of core files on operating systems that support it. For more information, seeSection 17.8.3.7, “Excluding or Including Buffer Pool Pages from Core Files”.

• --datadir=dir_name

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

  The path to the data directory.

• --defaults-extra-file=file_name

  Command-Line Format	--defaults-extra-file=file_name
  Type	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 exits with an error. Iffile_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, seeSection 6.2.2.3, “Command-Line Options that Affect Option-File Handling”.

• --defaults-file=file_name

  Command-Line Format	--defaults-file=file_name
  Type	File name

  Use only the given option file. If the file does not exist or is otherwise inaccessible, the server exits with an error. Iffile_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, seeSection 6.2.2.3, “Command-Line Options that Affect Option-File Handling”.

• --ledir=dir_name

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

  Ifmysqld_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 ofMYSQLD_OPTS. SeeSection 2.5.9, “Managing MySQL Server with systemd”.

• --log-error=file_name

  Command-Line Format	--log-error=file_name
  Type	File name

  Write the error log to the given file. SeeSection 7.4.2, “The Error Log”.

• --mysqld-safe-log-timestamps

  Command-Line Format	--mysqld-safe-log-timestamps=type
  Type	Enumeration
  Default Value	utc
  Valid Values	system hyphen legacy

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

  • UTC,utc

    ISO 8601 UTC format (same as--log_timestamps=UTC for the server). This is the default.

  • SYSTEM,system

    ISO 8601 local time format (same as--log_timestamps=SYSTEM for the server).

  • HYPHEN,hyphen

    YY-MM-DD h:mm:ss format, as inmysqld_safe for MySQL 5.6.

  • LEGACY,legacy

    YYMMDD hh:mm:ss format, as inmysqld_safe prior to MySQL 5.6.

• --malloc-lib=[lib_name]

  Command-Line Format	--malloc-lib=[lib-name]
  Type	String

  The name of the library to use for memory allocation instead of the systemmalloc() 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 theLD_PRELOAD environment value to affect dynamic linking to enable the loader to find the memory-allocation library whenmysqld runs:

  • If the option is not given, or is given without a value (--malloc-lib=),LD_PRELOAD is not modified and no attempt is made to usetcmalloc.

  • Prior to MySQL 8.0.21, if the option is given as--malloc-lib=tcmalloc,mysqld_safe looks for atcmalloc library in/usr/lib. Iftmalloc is found, its path name is added to the beginning of theLD_PRELOAD value formysqld. Iftcmalloc is not found,mysqld_safe aborts with an error.

    As of MySQL 8.0.21,tcmalloc is not a permitted value for the--malloc-lib option.

  • If the option is given as--malloc-lib=/path/to/some/library, that full path is added to the beginning of theLD_PRELOAD value. If the full path points to a nonexistent or unreadable file,mysqld_safe aborts with an error.

  • For cases wheremysqld_safe adds a path name toLD_PRELOAD, it adds the path to the beginning of any existing value the variable already has.

  Note

  On systems that manage the server using systemd,mysqld_safe is not available. Instead, specify the allocation library by settingLD_PRELOAD in/etc/sysconfig/mysql.

  Linux users can use thelibtcmalloc_minimal.so library on any platform for which atcmalloc package is installed in/usr/lib by adding these lines to themy.cnf file:

  [mysqld_safe]malloc-lib=tcmalloc

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

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

• --mysqld=prog_name

  Command-Line Format	--mysqld=file_name
  Type	File name

  The name of the server program (in theledir 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. Ifmysqld_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 ofMYSQLD_OPTS. SeeSection 2.5.9, “Managing MySQL Server with systemd”.

• --mysqld-version=suffix

  Command-Line Format	--mysqld-version=suffix
  Type	String

  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 bemysqld. For example, if you use--mysqld-version=debug,mysqld_safe starts themysqld-debug program in theledir directory. If the argument to--mysqld-version is empty,mysqld_safe usesmysqld in theledir 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 ofMYSQLD_OPTS. SeeSection 2.5.9, “Managing MySQL Server with systemd”.

• --nice=priority

  Command-Line Format	--nice=priority
  Type	Numeric

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

• --no-defaults

  Command-Line Format	--no-defaults
  Type	String

  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, seeSection 6.2.2.3, “Command-Line Options that Affect Option-File Handling”.

• --open-files-limit=count

  Command-Line Format	--open-files-limit=count
  Type	String

  The number of files thatmysqld should be able to open. The option value is passed toulimit -n.

  Note

  You must startmysqld_safe asroot for this to function properly.

• --pid-file=file_name

  Command-Line Format	--pid-file=file_name
  Type	File name

  The path name thatmysqld should use for its process ID file.

• --plugin-dir=dir_name

  Command-Line Format	--plugin-dir=dir_name
  Type	Directory name

  The path name of the plugin directory.

• --port=port_num

  Command-Line Format	--port=number
  Type	Numeric

  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 theroot operating system user.

• --skip-kill-mysqld

  Command-Line Format	--skip-kill-mysqld

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

• --socket=path

  Command-Line Format	--socket=file_name
  Type	File name

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

• --syslog,--skip-syslog

  Command-Line Format	--syslog
  Deprecated	Yes

  Command-Line Format	--skip-syslog
  Deprecated	Yes

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

  Whensyslog is used for error logging, thedaemon.err facility/severity is used for all log messages.

  Using these options to controlmysqld logging is deprecated. To write error log output to the system log, use the instructions atSection 7.4.2.8, “Error Logging to the System Log”. To control the facility, use the serverlog_syslog_facility system variable.

• --syslog-tag=tag

  Command-Line Format	--syslog-tag=tag
  Deprecated	Yes

  For logging tosyslog, messages frommysqld_safe andmysqld are written with identifiers ofmysqld_safe andmysqld, respectively. To specify a suffix for the identifiers, use--syslog-tag=tag, which modifies the identifiers to bemysqld_safe-tag andmysqld-tag.

  Using this option to controlmysqld logging is deprecated. Use the serverlog_syslog_tag system variable instead. SeeSection 7.4.2.8, “Error Logging to the System Log”.

• --timezone=timezone

  Command-Line Format	--timezone=timezone
  Type	String

  Set theTZ 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}

  Command-Line Format	--user={user_name|user_id}
  Type	String
  Type	Numeric

  Run themysqld server as the user having the nameuser_name or the numeric user IDuser_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 whichmysqld_safe is invoked). For binary distributions,mysqld_safe looks under its working directory forbin anddata directories. For source distributions, it looks forlibexec andvar directories. This condition should be met if you executemysqld_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 tosyslog on systems that support thelogger program.

• --skip-syslog: Do not write error messages tosyslog. 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.

Controllingmysqld logging frommysqld_safe is deprecated. Use the server's nativesyslog support instead. For more information, seeSection 7.4.2.8, “Error Logging to the System Log”.