mysqld_safe man page on SmartOS
MYSQLD_SAFE(1) MySQL Database System MYSQLD_SAFE(1)
mysqld_safe - MySQL server startup script
mysqld_safe is the recommended way to start a mysqld server on Unix.
mysqld_safe adds some safety features such as restarting the server
when an error occurs and logging runtime information to an error log
file. A description of error logging is given later in this section.
mysqld_safe tries to start an executable named mysqld. To override the
default behavior and specify explicitly the name of the server you want
to run, specify a --mysqld or --mysqld-version option to mysqld_safe.
You can also use --ledir to indicate the directory where mysqld_safe
should look for the server.
Many of the options to mysqld_safe are the same as the options to
mysqld. See Section 5.1.3, “Server Command Options”.
Options unknown to mysqld_safe are passed to mysqld if they are
specified on the command line, but ignored if they are specified in the
[mysqld_safe] group of an option file. See Section 22.214.171.124, “Using
mysqld_safe reads all options from the [mysqld], [server], and
[mysqld_safe] sections in option files. For example, if you specify a
[mysqld] section like this, mysqld_safe will find and use the
For backward compatibility, mysqld_safe also reads [safe_mysqld]
sections, although you should rename such sections to [mysqld_safe] in
MySQL 5.6 installations.
mysqld_safe supports the following options. It also reads option files
and supports the options for processing them described at
Section 126.96.36.199, “Command-Line Options that Affect Option-File
Display a help message and exit.
The path to the MySQL installation directory.
The size of the core file that mysqld should be able to create. The
option value is passed to ulimit -c.
The path to the data directory.
The name of an option file to be read in addition to the usual
option files. This must be the first option on the command line if
it is used. If the file does not exist or is otherwise
inaccessible, the server will exit with an error.
The name of an option file to be read instead of the usual option
files. This must be the first option on the command line if it is
If mysqld_safe cannot find the server, use this option to indicate
the path name to the directory where the server is located.
Write the error log to the given file. See Section 5.2.2, “The
The name of the library to use for memory allocation instead of the
system malloc() library. Any library can be used by specifying its
path name, but there is a shortcut form to enable use of the
tcmalloc library that is shipped with binary MySQL distributions
for Linux in MySQL 5.6. It is possible that the shortcut form will
not work under certain configurations, in which case you should
specify a path name instead.
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:
· 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 use tcmalloc.
· If the option is given as --malloc-lib=tcmalloc, mysqld_safe
looks for a tcmalloc library in /usr/lib and then in the MySQL
pkglibdir location (for example, /usr/local/mysql/lib or
whatever is appropriate). If tmalloc is found, its path name is
added to the beginning of the LD_PRELOAD value for mysqld. If
tcmalloc is not found, mysqld_safe aborts with an error.
· If the option is given as --malloc-lib=/path/to/some/library,
that full path is added to the beginning of the LD_PRELOAD
value. If the full path points to a nonexistent or unreadable
file, mysqld_safe aborts with an error.
· For cases where mysqld_safe adds a path name to LD_PRELOAD, it
adds the path to the beginning of any existing value the
variable already has.
Linux users can use the libtcmalloc_minimal.so included in binary
packages by adding these lines to the my.cnf file:
Those lines also suffice for users on any platform who have
installed a tcmalloc package in /usr/lib. To use a specific
tcmalloc library, specify its full path name. Example:
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 similar to the --mysqld option, but you specify only
the suffix for the server program name. The basename 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.
Use the nice program to set the server's scheduling priority to the
Do not read any option files. This must be the first option on the
command line if it is used.
The number of files that mysqld should be able to open. The option
value is passed to ulimit -n. Note that you need to start
mysqld_safe as root for this to work properly!
The path name of the process ID file.
The path name of the plugin directory.
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.
Do not try to kill stray mysqld processes at startup. This option
works only on Linux.
The Unix socket file that the server should use when listening for
· --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, the daemon.err syslog priority/facility is
used for all log messages.
For logging to syslog, messages from mysqld_safe and mysqld are
written with a tag of mysqld_safe and mysqld, respectively. To
specify a suffix for the tag, use --syslog-tag=tag, which modifies
the tags to be mysqld_safe-tag and mysqld-tag.
Set the TZ time zone environment variable to the given option
value. Consult your operating system documentation for legal time
zone specification formats.
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.)
If you execute mysqld_safe with the --defaults-file or
--defaults-extra-file option to name an option file, the option must be
the first one given on the command line or the option file will not be
used. For example, this command will not use the named option file:
mysql> mysqld_safe --port=port_num --defaults-file=file_name
Instead, use the following command:
mysql> mysqld_safe --defaults-file=file_name --port=port_num
The mysqld_safe script is written so that it normally can start a
server that was installed from either a source or a binary distribution
of MySQL, even though these types of distributions typically install
the server in slightly different locations. (See Section 2.1.5,
“Installation Layouts”.) mysqld_safe expects one of the following
conditions to be true:
· 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
Because mysqld_safe tries to find the server and databases relative to
its own working directory, you can install a binary distribution of
MySQL anywhere, as long as you run mysqld_safe from the MySQL
shell> cd mysql_installation_directory
shell> bin/mysqld_safe &
If mysqld_safe fails, even when invoked from the MySQL installation
directory, you can specify the --ledir and --datadir options to
indicate the directories in which the server and databases are located
on your system.
In MySQL 5.6.5 and later, mysqld_safe tries to use the sleep and date
system utilities to determine how many times it has attempted to start
this second, and—if these are present and this is greater than 5 times—
is forced to wait 1 full second before starting again. This is intended
to prevent excessive CPU usage in the event of repeated failures. (Bug
#11761530, Bug #54035)
When you use mysqld_safe to start mysqld, mysqld_safe arranges for
error (and notice) messages from itself and from mysqld to go to the
There are several mysqld_safe options for controlling the destination
of these messages:
· --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.
· --log-error=file_name: Write error messages to the named error
If none of these options is given, the default is --skip-syslog.
If --syslog and --log-error are both given, a warning is issued and
--log-error takes precedence.
When mysqld_safe writes a message, notices go to the logging
destination (syslog or the error log file) and stdout. Errors go to the
logging destination and stderr.
Normally, you should not edit the mysqld_safe script. Instead,
configure mysqld_safe by using command-line options or options in the
[mysqld_safe] section of a my.cnf option file. In rare cases, it might
be necessary to edit mysqld_safe to get it to start the server
properly. However, if you do this, your modified version of mysqld_safe
might be overwritten if you upgrade MySQL in the future, so you should
make a copy of your edited version that you can reinstall.
Copyright © 1997, 2014, Oracle and/or its affiliates. All rights
This documentation is free software; you can redistribute it and/or
modify it only under the terms of the GNU General Public License as
published by the Free Software Foundation; version 2 of the License.
This documentation is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License along
with the program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see
For more information, please refer to the MySQL Reference Manual, which
may already be installed locally and which is also available online at
Oracle Corporation (http://dev.mysql.com/).
MySQL 5.6 03/14/2014 MYSQLD_SAFE(1)
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