4.7.2 mysqld_safe, The Wrapper Around mysqld

mysqld_safe is the recommended way to start a mysqld daemon on Unix. mysqld_safe adds some safety features such as restarting the server when an error occurs and logging run-time information to a log file.

Note: Before MySQL 4.0, mysqld_safe is named safe_mysqld. To preserve backward compatibility, MySQL binary distributions for some time will include safe_mysqld as a symbolic link to mysqld_safe.

If you don't use --mysqld=# or --mysqld-version=# mysqld_safe will use an executable named mysqld-max if it exists. If not, mysqld_safe will start mysqld. This makes it very easy to test to use mysqld-max instead of mysqld; just copy mysqld-max to where you have mysqld and it will be used.

Normally one should never edit the mysqld_safe script, but instead put the options to mysqld_safe in the [mysqld_safe] section in the `my.cnf' file. mysqld_safe reads all options from the [mysqld], [server] and [mysqld_safe] sections from the option files. (For backward compatibility, it also reads the [safe_mysqld] sections.) See section 4.1.2 `my.cnf' Option Files.

Note that all options on the command-line to mysqld_safe are passed to mysqld. If you wants to use any options in mysqld_safe that mysqld doesn't support, you must specify these in the option file.

Most of the options to mysqld_safe are the same as the options to mysqld. See section 4.1.1 mysqld Command-line Options.

mysqld_safe supports the following options:

--basedir=path

--core-file-size=#

Size of the core file mysqld should be able to create. Passed to ulimit -c.

--datadir=path

--defaults-extra-file=path

--defaults-file=path

--err-log=path (this is marked obsolete in 4.0; Use --log-error instead)

--log-error=path

Write the error log to the above file. See section 4.9.1 The Error Log.

--ledir=path

Path to mysqld

--log=path

--mysqld=mysqld-version

Name of the mysqld version in the ledir directory you want to start.

--mysqld-version=version

Similar to --mysqld= but here you only give the suffix for mysqld. For example if you use --mysqld-version=max, mysqld_safe will start the ledir/mysqld-max version. If the argument to --mysqld-version is empty, ledir/mysqld will be used.

--nice=# (added in MySQL 4.0.14)

--no-defaults

--open-files-limit=#

Number of files mysqld should be able to open. Passed to ulimit -n. Note that you need to start mysqld_safe as root for this to work properly!

--pid-file=path

--port=#

--socket=path

--timezone=#

Set the timezone (the TZ) variable to the value of this parameter.

--user=#

The mysqld_safe script is written so that it normally is able to start a server that was installed from either a source or a binary version of MySQL, even if these install the server in slightly different locations. mysqld_safe expects one of these conditions to be true:

• The server and databases can be found relative to the directory from which mysqld_safe is invoked. mysqld_safe looks under its working directory for `bin' and `data' directories (for binary distributions) or for `libexec' and `var' directories (for source distributions). 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 pathnames. Typical locations are `/usr/local/libexec' and `/usr/local/var'. The actual locations are determined when the distribution was built from which mysqld_safe comes. They should be correct if MySQL was installed in a standard location.

Because mysqld_safe will try 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 start 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 modify it to use the path to mysqld and the pathname options that are correct for your system. Note that if you upgrade MySQL in the future, your modified version of mysqld_safe will be overwritten, so you should make a copy of your edited version that you can reinstall.

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