mysqld_safe - Unix, Linux Command
NAME
mysqld_safe - MySQL server startup script
SYNOPSIS
Tag | Description |
mysqld_safe options
|
DESCRIPTION
mysqld_safe
is the recommended way to start a
mysqld
server on Unix and NetWare.
mysqld_safe
adds some safety features such as restarting the server when an error occurs and logging runtime information to an error log file. Descriptions of error logging and NetWare-specific behaviors are given later in this section.
Note
In MySQL 5.1.20 (only), the default error logging behavior with
mysqld_safe
is to write errors to
syslog
on systems that support the
logger
program. This differs from the default behavior of writing an error log file for other versions.
In 5.1.20, logging to syslog may fail to operate correctly in some cases; if so, use --skip-syslog to use the default log file or --log-error=file_name to specify a log file name explicitly.
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 5.1.2, Server Command Options\(rq.
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 4.2.3.3, \(lqUsing Option Files\(rq.
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 you should rename such sections to
[mysqld_safe]
in MySQL 5.1 installations.
mysqld_safe
supports the options in the following list. It also reads option files and supports the options for processing them described at
Section 4.2.3.3.1, \(lqCommand-Line Options that Affect Option-File Handling\(rq.
o
Tag | Description |
o
|
--help
Display a help message and exit.
|
o
Tag | Description |
o
|
--autoclose
(NetWare only) On NetWare,
mysqld_safe
provides a screen presence. When you unload (shut down) the
mysqld_safe
NLM, the screen does not by default go away. Instead, it prompts for user input:
Tag | Description |
|
*<NLM has terminated; Press any key to close the screen>*
|
|
If you want NetWare to close the screen automatically instead, use the
--autoclose
option to
mysqld_safe.
|
o
Tag | Description |
o
|
--basedir=path
The path to the MySQL installation directory.
|
o
Tag | Description |
o
|
--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.
|
o
Tag | Description |
o
|
--datadir=path
The path to the data directory.
|
o
Tag | Description |
o
|
--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.
|
o
Tag | Description |
o
|
--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.
|
o
Tag | Description |
o
|
--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.
|
o
Tag | Description |
o
|
--log-error=file_name
Write the error log to the given file. See
Section 5.2.2, \(lqThe Error Log\(rq.
|
o
Tag | Description |
o
|
--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.
|
o
Tag | Description |
o
|
--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.
|
o
Tag | Description |
o
|
--nice=priority
Use the
nice
program to set the server's scheduling priority to the given value.
|
o
Tag | Description |
o
|
--no-defaults
Do not read any option files. This must be the first option on the command line if it is used.
|
o
Tag | Description |
o
|
--open-files-limit=count
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!
|
o
Tag | Description |
o
|
--pid-file=file_name
The path name of the process ID file.
|
o
Tag | Description |
o
|
--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.
|
o
Tag | Description |
o
|
--skip-kill-mysqld
Do not try to kill stray
mysqld
processes at startup. This option works only on Linux.
|
o
Tag | Description |
o
|
--socket=path
The Unix socket file that the server should use when listening for local connections.
|
o
Tag | Description |
o
|
--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. These options were added in MySQL 5.1.20.
|
o
Tag | Description |
o
|
--syslog-tag=tag
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. This option was added in MySQL 5.1.21.
|
o
Tag | Description |
o
|
--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.
|
o
Tag | Description |
o
|
--user={user_name|user_id}
Run the
mysqld
server as the user having the name
user_name
or the numeric user ID
user_id. (\(lqUser\(rq
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, \(lqInstallation Layouts\(rq.)
mysqld_safe
expects one of the following conditions to be true:
o
Tag | Description |
o
|
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).
|
o
Tag | Description |
o
|
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, you can specify the
--ledir
and
--datadir
options to indicate the directories in which the server and databases are located on your system.
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.
As of MySQL 5.1.20, there are several
mysqld_safe
options for controlling the destination of these messages:
o
Tag | Description |
o
|
--syslog: Write error messages to
syslog
on systems that support the
logger
program.
|
o
Tag | Description |
o
|
--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.
|
o
Tag | Description |
o
|
--log-error=file_name: Write error messages to the named error file.
|
If none of these options is given, the default is
--skip-syslog.
Note
In MySQL 5.1.20
only, the default is
--syslog. This differs from logging behavior for other versions of MySQL, for which the default is to write messages to the default error log file.
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.
Before MySQL 5.1.20, error logging is controlled only with the
--log-error
option. If it is given, messages go to the named error file. Otherwise, messages go to the default error file.
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.
On NetWare,
mysqld_safe
is a NetWare Loadable Module (NLM) that is ported from the original Unix shell script. It starts the server as follows:
1.
Tag | Description |
1.
|
Runs a number of system and option checks.
|
2.
Tag | Description |
2.
|
Runs a check on
MyISAM
tables.
|
3.
Tag | Description |
3.
|
Provides a screen presence for the MySQL server.
|
4.
Tag | Description |
4.
|
Starts
mysqld, monitors it, and restarts it if it terminates in error.
|
5.
Tag | Description |
5.
|
Sends error messages from
mysqld
to the
host_name.err
file in the data directory.
|
6.
Tag | Description |
6.
|
Sends
mysqld_safe
screen output to the
host_name.safe
file in the data directory.
|
COPYRIGHT
Copyright © 1997, 2011, 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/.
SEE ALSO
which may already be installed locally and which is also available
online at http://dev.mysql.com/doc/.
AUTHOR
Oracle Corporation (http://dev.mysql.com/).
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