- MySQL 5.1 Reference Manual :: 4 MySQL Programs :: 4.3 MySQL Server and Server-Startup Programs :: 4.3.2 mysqld_safe — MySQL Server Startup Script
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- MySQL 5.1 Reference Manual
- Preface, Notes, Licenses
- 1 General Information
- 2 Installing and Upgrading MySQL
- 3 Tutorial
- 4 MySQL Programs
- 5 MySQL Server Administration
- 6 Backup and Recovery
- 7 Optimization
- 8 Language Structure
- 9 Internationalization and Localization
- 10 Data Types
- 11 Functions and Operators
- 12 SQL Statement Syntax
- 13 Storage Engines
- 14 High Availability and Scalability
- 15 MySQL Enterprise Monitor
- 16 Replication
- 17 MySQL Cluster NDB 6.X/7.X
- 18 Partitioning
- 19 Stored Programs and Views
- 20 INFORMATION_SCHEMA Tables
- 21 Connectors and APIs
- 22 Extending MySQL
- A MySQL 5.1 Frequently Asked Questions
- B Errors, Error Codes, and Common Problems
- C MySQL Change History
- D Restrictions and Limits
- Index
- Standard Index
- C Function Index
- Command Index
- Function Index
- INFORMATION_SCHEMA Index
- Transaction Isolation Level Index
- JOIN Types Index
- Operator Index
- Option Index
- Privileges Index
- SQL Modes Index
- Status Variable Index
- Statement/Syntax Index
- System Variable Index
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=
to specify a log file name explicitly.file_name
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”.
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, “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 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, “Command-Line Options that Affect Option-File Handling”.
Table 4.1.
mysqld_safe
OptionsFormat Config File Description Introduction Deprecated Removed --autoclose autoclose On NetWare, mysqld_safe provides a screen presence --basedir=path basedir The path to the MySQL installation directory --core-file-size=size core-file-size The size of the core file that mysqld should be able to create --datadir=path datadir The path to the data directory --defaults-extra-file=path defaults-extra-file The name of an option file to be read in addition to the usual option files --defaults-file=file_name defaults-file The name of an option file to be read instead of the usual option files --help Display a help message and exit --ledir=path ledir Use this option to indicate the path name to the directory where the server is located --log-error=file_name log-error Write the error log to the given file --mysqld=prog_name mysqld The name of the server program (in the ledir directory) that you want to start --mysqld-version=suffix mysqld-version This option is similar to the --mysqld option, but you specify only the suffix for the server program name --nice=priority nice Use the nice program to set the server's scheduling priority to the given value --no-defaults no-defaults Do not read any option files --open-files-limit=count open-files-limit The number of files that mysqld should be able to open --pid-file pid-file The path name of the process ID file --port=number port The port number that the server should use when listening for TCP/IP connections --skip-kill-mysqld skip-kill-mysqld Do not try to kill stray mysqld processes --skip-syslog skip-syslog Do not write error messages to syslog; use error log file 5.1.20 --socket=path socket The Unix socket file that the server should use when listening for local connections --syslog syslog Write error messages to syslog 5.1.20 --timezone=timezone timezone Set the TZ time zone environment variable to the given option value --user={user_name|user_id} user Run the mysqld server as the user having the name user_name or the numeric user ID user_id -
Display a help message and exit.
-
(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:
*<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. -
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 used.
-
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 Error Log”.
-
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 theledir
directory. If the argument to--mysqld-version
is empty, mysqld_safe uses mysqld in theledir
directory. -
Use the
nice
program to set the server's scheduling priority to the given value. -
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 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 local connections.
-
--syslog
causes error messages to be sent tosyslog
on systems that support the logger program.--skip-syslog
suppresses the use ofsyslog
; messages are written to an error log file. These options were added in MySQL 5.1.20. -
For logging to
syslog
, messages from mysqld_safe and mysqld are written with a tag ofmysqld_safe
andmysqld
, respectively. To specify a suffix for the tag, use--syslog-tag=
, which modifies the tags to betag
mysqld_safe-
andtag
mysqld-
. This option was added in MySQL 5.1.21.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 IDuser_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
anddata
directories. For source distributions, it looks forlibexec
andvar
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
shell>mysql_installation_directory
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:
--syslog
: Write error messages tosyslog
on systems that support the logger program.--skip-syslog
: Do not write error messages tosyslog
. Messages are written to the default error log file (
in the data directory), or to a named file if thehost_name
.err--log-error
option is given.--log-error=
: Write error messages to the named error file.file_name
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) andstdout
. Errors go to the logging destination andstderr
.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 amy.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:
Runs a number of system and option checks.
Runs a check on
MyISAM
tables.Provides a screen presence for the MySQL server.
Starts mysqld, monitors it, and restarts it if it terminates in error.
Sends error messages from mysqld to the
file in the data directory.host_name
.errSends mysqld_safe screen output to the
file in the data directory.host_name
.safe