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. Descriptions 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.
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] or [mariadb_safe] groups of an option file.
mysqld_safe reads all options from the [mysqld], [server],
[mysqld_safe], and [mariadb_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 current installations.
mysqld_safe supports the options in the following list. It also
reads option files and supports the options for processing them.
• --help
Display a help message and exit.
• --basedir=path
The path to the MariaDB 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.
• --crash-script=file
Script to call in the event of mysqld crashing.
• --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.
• --flush-caches
Flush and purge buffers/caches before starting the server.
• --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.
• --malloc-lib=lib
Preload shared library lib if available.
• --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
MariaDB 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-auto-restart
Exit after starting mysqld.
• --no-defaults
Do not read any option files. This must be the first option
on the command line if it is used.
• --no-auto-restart
Exit after starting mysqld.
• --numa-interleave
Run mysqld with its memory interleaved on all NUMA nodes.
• --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!
• --pid-file=file_name
The path name of the process ID file.
• --plugin-dir=dir_name
Directory for client-side plugins.
• --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.
• --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.
• --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 MariaDB 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 MariaDB, even though these types of distributions
typically install the server in slightly different locations.
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
MariaDB 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 MariaDB 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 MariaDB anywhere, as long as you run mysqld_safe
from the MariaDB installation directory:
shell> cd mysql_installation_directory
shell> bin/mysqld_safe &
If mysqld_safe fails, even when invoked from the MariaDB
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.
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 file.
If none of these options is given, the default is --skip-syslog.
Note
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 MariaDB 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. Runs a number of system and option checks.
2. Runs a check on MyISAM tables.
3. Provides a screen presence for the MariaDB server.
4. Starts mysqld, monitors it, and restarts it if it terminates
in error.
5. Sends error messages from mysqld to the host_name.err file in
the data directory.
6. Sends mysqld_safe screen output to the host_name.safe file in
the data directory.
