mysqld_safe - Online in the Cloud

PROGRAM:

NAME

mysqld_safe - MySQL server startup script

SYNOPSIS

mysqld_safe options

DESCRIPTION

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 4.2.6, “Using Option Files”.

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 --log-error option:

[mysqld]
log-error=error.log

For backward compatibility, mysqld_safe also reads [safe_mysqld] sections, although it is
preferable to rename [safe_mysqld] sections to [mysqld_safe] sections.

mysqld_safe supports the following options. It also reads option files and supports the
options for processing them described at Section 4.2.7, “Command-Line Options that Affect
Option-File Handling”.

· --help

Display a help message and exit.

· --basedir=path

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=path

The path to the data directory.

· --defaults-extra-file=path

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.

· --defaults-file=file_name

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 used.

· --ledir=path

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

· --log-error=file_name

Write the error log to the given file. See Section 5.2.2, “The Error Log”.

· --malloc-lib=[lib_name]

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:

[mysqld_safe]
malloc-lib=tcmalloc

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:

[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.

· --mysqld-version=suffix

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.

· --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. This must be the first option on the command line if it
is used.

· --open-files-limit=count

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

Note
You must start mysqld_safe as root for this to function properly.

· --pid-file=file_name

The path name of the process ID file.

· --plugin-dir=path

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

· --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.

· --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.)

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 time.

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 installation directory:

shell> cd mysql_installation_directory
shell> bin/mysqld_safe &

If mysqld_safe fails, even when invoked from the MySQL installation directory, 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 same destination.

There are several mysqld_safe options for controlling the destination of these messages:

· --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.

If none of these options is given, the default is --skip-syslog.

If --log-error and --syslog 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.

COPYRIGHT

Copyright © 1997, 2014, Oracle and/or its affiliates. All rights reserved.

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 http://www.gnu.org/licenses/.

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