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Chapter 4. MySQL Programs
This chapter provides a brief overview of the MySQL command-line
programs provided by Sun Microsystems, Inc. It also discusses the
general syntax for specifying options when you run these programs.
Most programs have options that are specific to their own operation,
but the option syntax is similar for all of them. Finally, the
chapter provides more detailed descriptions of individual programs,
including which options they recognize.
4.1. Overview of MySQL Programs
There are many different programs in a MySQL installation. This
section provides a brief overview of them. Later sections provide
a more detailed description of each one, with the exception of
MySQL Cluster programs. Each program's description indicates its
invocation syntax and the options that it supports.
Chapter 17, MySQL Cluster NDB 6.X/7.X, describes programs specific to
MySQL Cluster.
Most MySQL distributions include all of these programs, except for
those programs that are platform-specific. (For example, the
server startup scripts are not used on Windows.) The exception is
that RPM distributions are more specialized. There is one RPM for
the server, another for client programs, and so forth. If you
appear to be missing one or more programs, see
Chapter 2, Installing and Upgrading MySQL, for information on types of
distributions and what they contain. It may be that you have a
distribution that does not include all programs and you need to
install an additional package.
Each MySQL program takes many different options. Most programs
provide a --help option that you can use to get a
description of the program's different options. For example, try
mysql --help.
You can override default option values for MySQL programs by
specifying options on the command line or in an option file. See
Section 4.2, “Using MySQL Programs”, for general information on
invoking programs and specifying program options.
The MySQL server, mysqld, is the main program
that does most of the work in a MySQL installation. The server is
accompanied by several related scripts that assist you in starting
and stopping the server:
There are several programs that perform setup operations during
MySQL installation or upgrading:
comp_err
This program is used during the MySQL build/installation
process. It compiles error message files from the error source
files. See Section 4.4.1, “comp_err — Compile MySQL Error Message File”.
make_binary_distribution
This program makes a binary release of a compiled MySQL. This
could be sent by FTP to
/pub/mysql/upload/ on
ftp.mysql.com for the convenience of other
MySQL users.
make_win_bin_dist
This program is used on Windows. It packages a MySQL
distribution for installation after the source distribution
has been built. See Section 4.4.2, “make_win_bin_dist — Package MySQL Distribution as ZIP Archive”.
mysql_fix_privilege_tables
This program is used after a MySQL upgrade operation. It
updates the grant tables with any changes that have been made
in newer versions of MySQL. See
Section 4.4.4, “mysql_fix_privilege_tables — Upgrade MySQL System Tables”.
Note: As of MySQL 5.1.7, this program has been superseded by
mysql_upgrade and should no longer be used.
mysql_install_db
This script creates the MySQL database and initializes the
grant tables with default privileges. It is usually executed
only once, when first installing MySQL on a system. See
Section 4.4.5, “mysql_install_db — Initialize MySQL Data Directory”,
Section 2.13.1, “Unix Post-Installation Procedures”, and
Section 4.4.5, “mysql_install_db — Initialize MySQL Data Directory”.
mysql_secure_installation
This program enables you to improve the security of your MySQL
installation. SQL. See
Section 4.4.6, “mysql_secure_installation — Improve MySQL Installation Security”.
mysql_tzinfo_to_sql
This program loads the time zone tables in the
mysql database using the contents of the
host system zoneinfo database (the set
of files describing time zones). SQL. See
Section 4.4.7, “mysql_tzinfo_to_sql — Load the Time Zone Tables”.
mysql_upgrade
This program is used after a MySQL upgrade operation. It
checks tables for incompatibilities and repairs them if
necessary, and updates the grant tables with any changes that
have been made in newer versions of MySQL. See
Section 4.4.8, “mysql_upgrade — Check Tables for MySQL Upgrade”.
MySQL client programs:
mysql
The command-line tool for interactively entering SQL
statements or executing them from a file in batch mode. See
Section 4.5.1, “mysql — The MySQL Command-Line Tool”.
mysqladmin
A client that performs administrative operations, such as
creating or dropping databases, reloading the grant tables,
flushing tables to disk, and reopening log files.
mysqladmin can also be used to retrieve
version, process, and status information from the server. See
Section 4.5.2, “mysqladmin — Client for Administering a MySQL Server”.
mysqlcheck
A table-maintenance client that checks, repairs, analyzes, and
optimizes tables. See Section 4.5.3, “mysqlcheck — A Table Maintenance Program”.
mysqldump
A client that dumps a MySQL database into a file as SQL, text,
or XML. See Section 4.5.4, “mysqldump — A Database Backup Program”.
mysqlimport
A client that imports text files into their respective tables
using LOAD DATA
INFILE. See Section 4.5.5, “mysqlimport — A Data Import Program”.
mysqlshow
A client that displays information about databases, tables,
columns, and indexes. See Section 4.5.6, “mysqlshow — Display Database, Table, and Column Information”.
mysqlslap
A client that is designed to emulate client load for a MySQL
server and report the timing of each stage. It works as if
multiple clients are accessing the server. See
Section 4.5.7, “mysqlslap — Load Emulation Client”.
MySQL administrative and utility programs:
innochecksum
An offline InnoDB offline file checksum
utility. See Section 4.6.1, “innochecksum — Offline InnoDB File Checksum Utility”.
myisam_ftdump
A utility that displays information about full-text indexes in
MyISAM tables. See
Section 4.6.2, “myisam_ftdump — Display Full-Text Index information”.
myisamchk
A utility to describe, check, optimize, and repair
MyISAM tables. See
Section 4.6.3, “myisamchk — MyISAM Table-Maintenance Utility”.
myisamlog, isamlog
A utility that processes the contents of a
MyISAM log file. See
Section 4.6.4, “myisamlog — Display MyISAM Log File Contents”.
myisampack
A utility that compresses MyISAM tables to
produce smaller read-only tables. See
Section 4.6.5, “myisampack — Generate Compressed, Read-Only MyISAM Tables”.
mysqlaccess
A script that checks the access privileges for a host name,
user name, and database combination. See
Section 4.6.6, “mysqlaccess — Client for Checking Access Privileges”.
mysqlbinlog
A utility for reading statements from a binary log. The log of
executed statements contained in the binary log files can be
used to help recover from a crash. See
Section 4.6.7, “mysqlbinlog — Utility for Processing Binary Log Files”.
mysqldumpslow
A utility to read and summarize the contents of a slow query
log. See Section 4.6.8, “mysqldumpslow — Summarize Slow Query Log Files”.
mysqlhotcopy
A utility that quickly makes backups of
MyISAM tables while the server is running.
See Section 4.6.9, “mysqlhotcopy — A Database Backup Program”.
mysqlmanager
The MySQL Instance Manager, a program for monitoring and
managing MySQL servers. See
Section 4.6.10, “mysqlmanager — The MySQL Instance Manager”.
Important
MySQL Instance Manager has been deprecated and is removed in
MySQL 5.4.
mysql_convert_table_format
A utility that converts tables in a database to use a given
storage engine. See
Section 4.6.11, “mysql_convert_table_format — Convert Tables to Use a Given Storage
Engine”.
mysql_find_rows
A utility that reads files containing SQL statements (such as
update logs) and extracts statements that match a given
regular expression. See Section 4.6.12, “mysql_find_rows — Extract SQL Statements from Files”.
mysql_fix_extensions
A utility that converts the extensions for
MyISAM table files to lowercase. This can
be useful after transferring the files from a system with
case-insensitive file names to a system with case-sensitive
file names. See Section 4.6.13, “mysql_fix_extensions — Normalize Table File Name Extensions”.
mysql_setpermission
A utility for interactively setting permissions in the MySQL
grant tables. See Section 4.6.14, “mysql_setpermission — Interactively Set Permissions in Grant
Tables”.
mysql_waitpid
A utility that kills the process with a given process ID. See
Section 4.6.15, “mysql_waitpid — Kill Process and Wait for Its Termination”.
mysql_zap
A utility that kills processes that match a pattern. See
Section 4.6.16, “mysql_zap — Kill Processes That Match a Pattern”.
MySQL program-development utilities:
Miscellaneous utilities:
Sun Microsystems, Inc. also provides several GUI tools for
administering and otherwise working with MySQL Server:
MySQL Workbench: This is the latest graphical tool for working
with MySQL databases.
MySQL Administrator: This tool is used for administering MySQL
servers, databases, tables, and user accounts.
MySQL Query Browser: This graphical tool is used for creating,
executing, and optimizing queries on MySQL databases.
MySQL Migration Toolkit: This tool helps you migrate schemas
and data from other relational database management systems for
use with MySQL.
These GUI programs are available at
http://dev.mysql.com/downloads/. Each has its own manual that
you can access at http://dev.mysql.com/doc/.
MySQL client programs that communicate with the server using the
MySQL client/server library use the following environment
variables.
For a full list of environment variables used by MySQL programs,
see Section 2.14, “Environment Variables”.
Use of MYSQL_PWD is insecure. See
Section 5.5.6.2, “End-User Guidelines for Password Security”.
4.2. Using MySQL Programs4.2.1. Invoking MySQL Programs
To invoke a MySQL program from the command line (that is, from
your shell or command prompt), enter the program name followed by
any options or other arguments needed to instruct the program what
you want it to do. The following commands show some sample program
invocations. “shell>”
represents the prompt for your command interpreter; it is not part
of what you type. The particular prompt you see depends on your
command interpreter. Typical prompts are $ for
sh or bash,
% for csh or
tcsh, and C:\> for the
Windows command.com or
cmd.exe command interpreters.
shell> mysql --user=root test
shell> mysqladmin extended-status variables
shell> mysqlshow --help
shell> mysqldump -u root personnel
Arguments that begin with a single or double dash
(“-”,
“--”) specify program options.
Options typically indicate the type of connection a program should
make to the server or affect its operational mode. Option syntax
is described in Section 4.2.3, “Specifying Program Options”.
Nonoption arguments (arguments with no leading dash) provide
additional information to the program. For example, the
mysql program interprets the first nonoption
argument as a database name, so the command mysql
--user=root test indicates that you want to use the
test database.
Later sections that describe individual programs indicate which
options a program supports and describe the meaning of any
additional nonoption arguments.
Some options are common to a number of programs. The most
frequently used of these are the
--host (or -h),
--user (or -u),
and --password (or
-p) options that specify connection parameters.
They indicate the host where the MySQL server is running, and the
user name and password of your MySQL account. All MySQL client
programs understand these options; they allow you to specify which
server to connect to and the account to use on that server. Other
connection options are --port (or
-P) to specify a TCP/IP port number and
--socket (or -S)
to specify a Unix socket file on Unix (or named pipe name on
Windows). For more information on options that specify connection
options, see Section 4.2.2, “Connecting to the MySQL Server”.
You may find it necessary to invoke MySQL programs using the path
name to the bin directory in which they are
installed. This is likely to be the case if you get a
“program not found” error whenever you attempt to run
a MySQL program from any directory other than the
bin directory. To make it more convenient to
use MySQL, you can add the path name of the
bin directory to your PATH
environment variable setting. That enables you to run a program by
typing only its name, not its entire path name. For example, if
mysql is installed in
/usr/local/mysql/bin, you can run the program
by invoking it as mysql, and it is not
necessary to invoke it as
/usr/local/mysql/bin/mysql.
Consult the documentation for your command interpreter for
instructions on setting your PATH variable. The
syntax for setting environment variables is interpreter-specific.
(Some information is given in
Section 4.2.4, “Setting Environment Variables”.) After modifying
your PATH setting, open a new console window on
Windows or log in again on Unix so that the setting goes into
effect.
4.2.2. Connecting to the MySQL Server
For a client program to be able to connect to the MySQL server, it
must use the proper connection parameters, such as the name of the
host where the server is running and the user name and password of
your MySQL account. Each connection parameter has a default value,
but you can override them as necessary using program options
specified either on the command line or in an option file.
The examples here use the mysql client program,
but the principles apply to other clients such as
mysqldump, mysqladmin, or
mysqlshow.
This command invokes mysql without specifying
any connection parameters explicitly:
shell> mysql
Because there are no parameter options, the default values apply:
The default host name is localhost. On
Unix, this has a special meaning, as described later.
The default user name is ODBC on Windows or
your Unix login name on Unix.
No password is sent if neither -p nor
--password is given.
For mysql, the first nonoption argument is
taken as the name of the default database. If there is no such
option, mysql does not select a default
database.
To specify the host name and user name explicitly, as well as a
password, supply appropriate options on the command line:
shell> mysql --host=localhost --user=myname --password=mypass mydb
shell> mysql -h localhost -u myname -pmypass mydb
For password options, the password value is optional:
If you use a -p or
--password option and specify
the password value, there must be no
space between -p or
--password= and the password
following it.
If you use a -p or
--password option but do not
specify the password value, the client program prompts you to
enter the password. The password is not displayed as you enter
it. This is more secure than giving the password on the
command line. Other users on your system may be able to see a
password specified on the command line by executing a command
such as ps auxw. See
Section 5.5.6.2, “End-User Guidelines for Password Security”.
As just mentioned, including the password value on the command
line can be a security risk. To avoid this problem, specify the
--password or -p option without
any following password value:
shell> mysql --host=localhost --user=myname --password mydb
shell> mysql -h localhost -u myname -p mydb
When the password option has no password value, the client program
prints a prompt and waits for you to enter the password. (In these
examples, mydb is not
interpreted as a password because it is separated from the
preceding password option by a space.)
On some systems, the library routine that MySQL uses to prompt for
a password automatically limits the password to eight characters.
That is a problem with the system library, not with MySQL.
Internally, MySQL does not have any limit for the length of the
password. To work around the problem, change your MySQL password
to a value that is eight or fewer characters long, or put your
password in an option file.
On Unix, MySQL programs treat the host name
localhost specially, in a way that is likely
different from what you expect compared to other network-based
programs. For connections to localhost, MySQL
programs attempt to connect to the local server by using a Unix
socket file. This occurs even if a
--port or -P
option is given to specify a port number. To ensure that the
client makes a TCP/IP connection to the local server, use
--host or -h to
specify a host name value of 127.0.0.1, or the
IP address or name of the local server. You can also specify the
connection protocol explicitly, even for
localhost, by using the
--protocol=TCP option. For
example:
shell> mysql --host=127.0.0.1
shell> mysql --protocol=TCP
The --protocol option enables you
to establish a particular type of connection even when the other
options would normally default to some other protocol.
On Windows, you can force a MySQL client to use a named-pipe
connection by specifying the
--pipe or
--protocol=PIPE option, or by
specifying . (period) as the host name. If
named-pipe connections are not enabled, an error occurs. Use the
--socket option to specify the
name of the pipe if you do not want to use the default pipe name.
Connections to remote servers always use TCP/IP. This command
connects to the server running on
remote.example.com using the default port
number (3306):
shell> mysql --host=remote.example.com
To specify a port number explicitly, use the
--port or -P
option:
shell> mysql --host=remote.example.com --port=13306
You can specify a port number for connections to a local server,
too. However, as indicated previously, connections to
localhost on Unix will use a socket file by
default. You will need to force a TCP/IP connection as already
described or any option that specifies a port number will be
ignored.
For this command, the program uses a socket file on Unix and the
--port option is ignored:
shell> mysql --port=13306 --host=localhost
To cause the port number to be used, invoke the program in either
of these ways:
shell> mysql --port=13306 --host=127.0.0.1
shell> mysql --port=13306 --protocol=TCP
The following list summarizes the options that can be used to
control how client programs connect to the server:
--host=host_name,
-h host_name
The host where the server is running. The default value is
localhost.
--password[=pass_val],
-p[pass_val]
The password of the MySQL account. As described earlier, the
password value is optional, but if given, there must be
no space between -p or
--password= and the password
following it. The default is to send no password.
--pipe, -W
On Windows, connect to the server via a named pipe. The server
must be started with the
--enable-named-pipe option to
enable named-pipe connections.
--port=port_num,
-P port_num
The port number to use for the connection, for connections
made via TCP/IP. The default port number is 3306.
--protocol={TCP|SOCKET|PIPE|MEMORY}
This option explicitly specifies a protocol to use for
connecting to the server. It is useful when the other
connection parameters normally would cause a protocol to be
used other than the one you want. For example, connections on
Unix to localhost are made via a Unix
socket file by default:
shell> mysql --host=localhost
To force a TCP/IP connection to be used instead, specify a
--protocol option:
shell> mysql --host=localhost --protocol=TCP
The following table shows the allowable
--protocol option values and
indicates the platforms on which each value may be used. The
values are not case sensitive.
--shared-memory-base-name=name
On Windows, the shared-memory name to use, for connections
made via shared memory to a local server. The default value is
MYSQL. The shared-memory name is case
sensitive.
The server must be started with the
--shared-memory option to
enable shared-memory connections.
--socket=file_name,
-S file_name
On Unix, the name of the Unix socket file to use, for
connections made via a named pipe to a local server. The
default Unix socket file name is
/tmp/mysql.sock.
On Windows, the name of the named pipe to use, for connections
to a local server. The default Windows pipe name is
MySQL. The pipe name is not case sensitive.
The server must be started with the
--enable-named-pipe option to
enable named-pipe connections.
--ssl*
Options that begin with --ssl
are used for establishing a secure connection to the server
via SSL, if the server is configured with SSL support. For
details, see Section 5.5.7.3, “SSL Command Options”.
--user=user_name,
-u user_name
The user name of the MySQL account you want to use. The
default user name is ODBC on Windows or
your Unix login name on Unix.
It is possible to specify different default values to be used when
you make a connection so that you need not enter them on the
command line each time you invoke a client program. This can be
done in a couple of ways:
4.2.3. Specifying Program Options
There are several ways to specify options for MySQL programs:
List the options on the command line following the program
name. This is most common for options that apply to a specific
invocation of the program.
List the options in an option file that the program reads when
it starts. This is common for options that you want the
program to use each time it runs.
List the options in environment variables (see
Section 4.2.4, “Setting Environment Variables”). This method
is useful for options that you want to apply each time the
program runs. In practice, option files are used more commonly
for this purpose, but Section 5.6.2, “Running Multiple Servers on Unix”,
discusses one situation in which environment variables can be
very helpful. It describes a handy technique that uses such
variables to specify the TCP/IP port number and Unix socket
file for the server and for client programs.
MySQL programs determine which options are given first by
examining environment variables, then by reading option files, and
then by checking the command line. This means that environment
variables have the lowest precedence and command-line options the
highest.
Because options are processed in order, if an option is specified
multiple times, the last occurrence takes precedence. The
following command causes mysql to connect to
the server running on localhost:
shell> mysql -h example.com -h localhost
If conflicting or related options are given, later options take
precedence over earlier options. The following command runs
mysql in “no column names” mode:
shell> mysql --column-names --skip-column-names
An option can be specified by writing it in full or as any
unambiguous prefix. For example, the
--compress option can be given
to mysqldump as --compr, but
not as --comp because the latter is ambiguous:
shell> mysqldump --comp
mysqldump: ambiguous option '--comp' (compatible, compress)
Be aware that the use of option prefixes can cause problems in the
event that new options are implemented for a program. A prefix
that is unambiguous now might become ambiguous in the future.
You can take advantage of the way that MySQL programs process
options by specifying default values for a program's options in an
option file. That enables you to avoid typing them each time you
run the program, but also allows you to override the defaults if
necessary by using command-line options.
4.2.3.1. Using Options on the Command Line
Program options specified on the command line follow these
rules:
Options are given after the command name.
An option argument begins with one dash or two dashes,
depending on whether it is a short form or long form of the
option name. Many options have both short and long forms.
For example, -? and --help
are the short and long forms of the option that instructs a
MySQL program to display its help message.
Option names are case sensitive. -v and
-V are both legal and have different
meanings. (They are the corresponding short forms of the
--verbose and --version
options.)
Some options take a value following the option name. For
example, -h localhost or
--host=localhost indicate
the MySQL server host to a client program. The option value
tells the program the name of the host where the MySQL
server is running.
For a long option that takes a value, separate the option
name and the value by an “=”
sign. For a short option that takes a value, the option
value can immediately follow the option letter, or there can
be a space between: -hlocalhost and
-h localhost are equivalent. An exception
to this rule is the option for specifying your MySQL
password. This option can be given in long form as
--password=pass_val
or as --password. In the
latter case (with no password value given), the program
prompts you for the password. The password option also may
be given in short form as
-ppass_val or as
-p. However, for the short form, if the
password value is given, it must follow the option letter
with no intervening space. The reason
for this is that if a space follows the option letter, the
program has no way to tell whether a following argument is
supposed to be the password value or some other kind of
argument. Consequently, the following two commands have two
completely different meanings:
shell> mysql -ptest
shell> mysql -p test
The first command instructs mysql to use
a password value of test, but specifies
no default database. The second instructs
mysql to prompt for the password value
and to use test as the default database.
Within option names, dash
(“-”) and underscore
(“_”) may be used
interchangeably. For example,
--skip-grant-tables and
--skip_grant_tables
are equivalent. (However, the leading dashes cannot be given
as underscores.)
Another option that may occasionally be useful with
mysql is the
--execute or -e
option, which can be used to pass SQL statements to the server.
When this option is used, mysql executes the
statements and exits. The statements must be enclosed by
quotation marks. For example, you can use the following command
to obtain a list of user accounts:
shell> mysql -u root -p --execute="SELECT User, Host FROM user" mysql
Enter password: ******
+------+-----------+
| User | Host |
+------+-----------+
| | gigan |
| root | gigan |
| | localhost |
| jon | localhost |
| root | localhost |
+------+-----------+
shell>
Note that the long form
(--execute) is followed by an
equals sign (=).
If you wish to use quoted values within a statement, you will
either need to escape the inner quotes, or use a different type
of quotes within the statement from those used to quote the
statement itself. The capabilities of your command processor
dictate your choices for whether you can use single or double
quotation marks and the syntax for escaping quote characters.
For example, if your command processor supports quoting with
single or double quotes, you can double quotes around the
statement, and single quotes for any quoted values within the
statement.
In the preceding example, the name of the
mysql database was passed as a separate
argument. However, the same statement could have been executed
using this command, which specifies no default database:
mysql> mysql -u root -p --execute="SELECT User, Host FROM mysql.user"
Multiple SQL statements may be passed on the command line,
separated by semicolons:
shell> mysql -u root -p -e "SELECT VERSION();SELECT NOW()"
Enter password: ******
+-----------------+
| VERSION() |
+-----------------+
| 5.1.5-alpha-log |
+-----------------+
+---------------------+
| NOW() |
+---------------------+
| 2006-01-05 21:19:04 |
+---------------------+
The --execute or -e option may
also be used to pass commands in an analogous fashion to the
ndb_mgm management client for MySQL Cluster.
See Section 17.2.5, “Safe Shutdown and Restart of MySQL Cluster”, for
an example.
4.2.3.2. Program Option Modifiers
Some options are “boolean” and control behavior
that can be turned on or off. For example, the
mysql client supports a
--column-names option that
determines whether or not to display a row of column names at
the beginning of query results. By default, this option is
enabled. However, you may want to disable it in some instances,
such as when sending the output of mysql into
another program that expects to see only data and not an initial
header line.
To disable column names, you can specify the option using any of
these forms:
--disable-column-names
--skip-column-names
--column-names=0
The --disable and --skip
prefixes and the =0 suffix all have the same
effect: They turn the option off.
The “enabled” form of the option may be specified
in any of these ways:
--column-names
--enable-column-names
--column-names=1
If an option is prefixed by --loose, a program
does not exit with an error if it does not recognize the option,
but instead issues only a warning:
shell> mysql --loose-no-such-option
mysql: WARNING: unknown option '--no-such-option'
The --loose prefix can be useful when you run
programs from multiple installations of MySQL on the same
machine and list options in an option file, An option that may
not be recognized by all versions of a program can be given
using the --loose prefix (or
loose in an option file). Versions of the
program that recognize the option process it normally, and
versions that do not recognize it issue a warning and ignore it.
mysqld enables a limit to be placed on how
large client programs can set dynamic system variables. To do
this, use a --maximum prefix with the variable
name. For example,
--maximum-query_cache_size=4M prevents any
client from making the query cache size larger than 4MB.
4.2.3.3. Using Option Files
Most MySQL programs can read startup options from option files
(also sometimes called configuration files). Option files
provide a convenient way to specify commonly used options so
that they need not be entered on the command line each time you
run a program. For the MySQL server, MySQL provides a number of
preconfigured option
files.
To determine whether a program reads option files, invoke it
with the --help option. (For
mysqld, use
--verbose and
--help.) If the program reads
option files, the help message indicates which files it looks
for and which option groups it recognizes.
On Windows, MySQL programs read startup options from the
following files.
WINDIR represents the location of
your Windows directory. This is commonly
C:\WINDOWS. You can determine its exact
location from the value of the WINDIR
environment variable using the following command:
C:\> echo %WINDIR%
INSTALLDIR represents the MySQL
installation directory. This is typically
C:\PROGRAMDIR\MySQL\MySQL
5.1 Server where
PROGRAMDIR represents the programs
directory (usually Program Files on
English-language versions of Windows), when MySQL
5.1 has been installed using the installation and
configuration wizards. See
The Location of the my.ini File.
On Unix, MySQL programs read startup options from the following
files.
SYSCONFDIR represents the directory
specified with the --sysconfdir option to
configure when MySQL was built. By default,
this is the etc directory located under the
compiled-in installation directory. This location is used as of
MySQL 5.1.10. (From 5.1.10 to 5.1.22, it was read last, after
~/.my.cnf.)
MYSQL_HOME is an environment variable
containing the path to the directory in which the
server-specific my.cnf file resides.
If MYSQL_HOME is not set and you start the
server using the mysqld_safe program,
mysqld_safe attempts to set
MYSQL_HOME as follows:
Let BASEDIR and
DATADIR represent the path names
of the MySQL base directory and data directory,
respectively.
If there is a my.cnf file in
DATADIR but not in
BASEDIR,
mysqld_safe sets
MYSQL_HOME to
DATADIR.
Otherwise, if MYSQL_HOME is not set and
there is no my.cnf file in
DATADIR,
mysqld_safe sets
MYSQL_HOME to
BASEDIR.
In MySQL 5.1, use of
DATADIR as the location for
my.cnf is deprecated.
Typically, DATADIR is
/usr/local/mysql/data for a binary
installation or /usr/local/var for a source
installation. Note that this is the data directory location that
was specified at configuration time, not the one specified with
the --datadir option when
mysqld starts. Use of
--datadir at runtime has no
effect on where the server looks for option files, because it
looks for them before processing any options.
MySQL looks for option files in the order just described and
reads any that exist. If an option file that you want to use
does not exist, create it with a plain text editor.
If multiple instances of a given option are found, the last
instance takes precedence. There is one exception: For
mysqld, the first
instance of the --user option is
used as a security precaution, to prevent a user specified in an
option file from being overridden on the command line.
Note
On Unix platforms, MySQL ignores configuration files that are
world-writable. This is intentional as a security measure.
Any long option that may be given on the command line when
running a MySQL program can be given in an option file as well.
To get the list of available options for a program, run it with
the --help option.
The syntax for specifying options in an option file is similar
to command-line syntax, except that you omit the leading two
dashes and you specify only one option per line. For example,
--quick and --host=localhost
on the command line should be specified as
quick and host=localhost
on separate lines in an option file. To specify an option of the
form
--loose-opt_name in
an option file, write it as
loose-opt_name.
Empty lines in option files are ignored. Nonempty lines can take
any of the following forms:
#comment,
;comment
Comment lines start with “#”
or “;”. A
“#” comment can start in the
middle of a line as well.
[group]
group is the name of the program
or group for which you want to set options. After a group
line, any option-setting lines apply to the named group
until the end of the option file or another group line is
given.
opt_name
This is equivalent to
--opt_name on
the command line.
opt_name=value
This is equivalent to
--opt_name=value
on the command line. In an option file, you can have spaces
around the “=” character,
something that is not true on the command line. You can
optionally enclose the value within single quotes or double
quotes, which is useful if the value contains a
“#” comment character.
For options that take a numeric value, the value can be given
with a suffix of K, M, or
G (either uppercase or lowercase) to indicate
a multiplier of 1024, 10242 or
10243. For example, the following
command tells mysqladmin to ping the server
1024 times, sleeping 10 seconds between each ping:
mysql> mysqladmin --count=1K --sleep=10 ping
Leading and trailing blanks are automatically deleted from
option names and values.
You can use the escape sequences
“\b”,
“\t”,
“\n”,
“\r”,
“\\”, and
“\s” in option values to
represent the backspace, tab, newline, carriage return,
backslash, and space characters. The escaping rules in option
files are:
If a backslash is followed by a valid escape sequence
character, the sequence is converted to the character
represented by the sequence. For example,
“\s” is converted to a
space.
If a backslash is not followed by a valid escape sequence
character, it remains unchanged. For example,
“\S” is retained as is.
The preceding rules mean that a literal backslash can be given
as “\\”, or as
“\” if it is not followed by a
valid escape sequence character.
The rules for escape sequences in option files differ slightly
from the rules for escape sequences in string literals in SQL
statements. In the latter context, if
“x” is not a value
escape sequence character,
“\x”
becomes “x” rather than
“\x”.
See Section 8.1.1, “Strings”.
The escaping rules for option file values are especially
pertinent for Windows path names, which use
“\” as a path name separator. A
separator in a Windows path name must be written as
“\\” if it is followed by an
escape sequence character. It can be written as
“\\” or
“\” if it is not. Alternatively,
“/” may be used in Windows path
names and will be treated as
“\”. Suppose that you want to
specify a base directory of C:\Program
Files\MySQL\MySQL Server 5.1 in an
option file. This can be done several ways. Some examples:
basedir="C:\Program Files\MySQL\MySQL Server 5.1"
basedir="C:\\Program Files\\MySQL\\MySQL Server 5.1"
basedir="C:/Program Files/MySQL/MySQL Server 5.1"
basedir=C:\\Program\sFiles\\MySQL\\MySQL\sServer\s5.1
If an option group name is the same as a program name, options
in the group apply specifically to that program. For example,
the [mysqld] and [mysql]
groups apply to the mysqld server and the
mysql client program, respectively.
The [client] option group is read by all
client programs (but not by
mysqld). This allows you to specify options
that apply to all clients. For example,
[client] is the perfect group to use to
specify the password that you use to connect to the server. (But
make sure that the option file is readable and writable only by
yourself, so that other people cannot find out your password.)
Be sure not to put an option in the [client]
group unless it is recognized by all client
programs that you use. Programs that do not understand the
option quit after displaying an error message if you try to run
them.
Here is a typical global option file:
[client]
port=3306
socket=/tmp/mysql.sock
[mysqld]
port=3306
socket=/tmp/mysql.sock
key_buffer_size=16M
max_allowed_packet=8M
[mysqldump]
quick
The preceding option file uses
var_name=value
syntax for the lines that set the
key_buffer_size and
max_allowed_packet variables.
Here is a typical user option file:
[client]
# The following password will be sent to all standard MySQL clients
password="my_password"
[mysql]
no-auto-rehash
connect_timeout=2
[mysqlhotcopy]
interactive-timeout
If you want to create option groups that should be read by
mysqld servers from a specific MySQL release
series only, you can do this by using groups with names of
[mysqld-5.0],
[mysqld-5.1], and so forth. The
following group indicates that the --new option
should be used only by MySQL servers with 5.1.x
version numbers:
[mysqld-5.1]
new
It is possible to use !include directives in
option files to include other option files and
!includedir to search specific directories
for option files. For example, to include the
/home/mydir/myopt.cnf file, use the
following directive:
!include /home/mydir/myopt.cnf
To search the /home/mydir directory and
read option files found there, use this directive:
!includedir /home/mydir
There is no guarantee about the order in which the option files
in the directory will be read.
Note
Currently, any files to be found and included using the
!includedir directive on Unix operating
systems must have file names ending in
.cnf. On Windows, this directive checks
for files with the .ini or
.cnf extension.
Write the contents of an included option file like any other
option file. That is, it should contain groups of options, each
preceded by a
[group] line that
indicates the program to which the options apply.
While an included file is being processed, only those options in
groups that the current program is looking for are used. Other
groups are ignored. Suppose that a my.cnf
file contains this line:
!include /home/mydir/myopt.cnf
And suppose that /home/mydir/myopt.cnf
looks like this:
[mysqladmin]
force
[mysqld]
key_buffer_size=16M
If my.cnf is processed by
mysqld, only the [mysqld]
group in /home/mydir/myopt.cnf is used. If
the file is processed by mysqladmin, only the
[mysqldamin] group is used. If the file is
processed by any other program, no options in
/home/mydir/myopt.cnf are used.
The !includedir directive is processed
similarly except that all option files in the named directory
are read.
4.2.3.3.1. Command-Line Options that Affect Option-File Handling
Most MySQL programs that support option files handle the
following options. They affect option-file handling, so they
must be given on the command line and not in an option file.
To work properly, each of these options must immediately
follow the command name, with the exception that
--print-defaults may be used
immediately after
--defaults-file or
--defaults-extra-file. Also,
when specifying file names, you should avoid the use of the
“~” shell metacharacter
because it might not be interpreted as you expect.
--defaults-extra-file=file_name
Read this option file after the global option file but (on
Unix) before the user option file.
file_name is the full path name
to the file. If the file does not exist or is otherwise
inaccessible, the program will exit with an error.
--defaults-file=file_name
Use only the given option file.
file_name is the full path name
to the file. If the file does not exist or is otherwise
inaccessible, the program will exit with an error.
--defaults-group-suffix=str
If this option is given, the program reads not only its
usual option groups, but also groups with the usual names
and a suffix of str. For
example, the mysql client normally
reads the [client] and
[mysql] groups. If the
--defaults-group-suffix=_other
option is given, mysql also reads the
[client_other] and
[mysql_other] groups.
--no-defaults
Do not read any option files. If a program does not start
because it is reading unknown options from an option file,
--no-defaults can be used
to prevent the program from reading them.
--print-defaults
Print the program name and all options that it gets from
option files.
4.2.3.3.2. Preconfigured Option Files
MySQL provides a number of preconfigured option files that can
be used as a basis for tuning the MySQL server. Look for files
such as my-small.cnf,
my-medium.cnf,
my-large.cnf, and
my-huge.cnf, which are sample option
files for small, medium, large, and very large systems. On
Windows, the extension is .ini rather
than .cnf.
Note
On Windows, the .ini or
.cnf option file extension might not be
displayed.
For a binary distribution, look for the files in or under your
installation directory. If you have a source distribution,
look in the support-files directory. You
can rename a copy of a sample file and place it in the
appropriate location for use as a base configuration file.
Regarding names and appropriate location, see the general
information provided in Section 4.2.3.3, “Using Option Files”.
4.2.3.4. Using Options to Set Program Variables
Many MySQL programs have internal variables that can be set at
runtime using the
SET
statement. See Section 12.5.4, “SET Syntax”, and
Section 5.1.6, “Using System Variables”.
Most of these program variables also can be set at server
startup by using the same syntax that applies to specifying
program options. For example, mysql has a
max_allowed_packet variable that controls the
maximum size of its communication buffer. To set the
max_allowed_packet variable for
mysql to a value of 16MB, use either of the
following commands:
shell> mysql --max_allowed_packet=16777216
shell> mysql --max_allowed_packet=16M
The first command specifies the value in bytes. The second
specifies the value in megabytes. For variables that take a
numeric value, the value can be given with a suffix of
K, M, or
G (either uppercase or lowercase) to indicate
a multiplier of 1024, 10242 or
10243. (For example, when used to set
max_allowed_packet, the suffixes indicate
units of kilobytes, megabytes, or gigabytes.)
In an option file, variable settings are given without the
leading dashes:
[mysql]
max_allowed_packet=16777216
Or:
[mysql]
max_allowed_packet=16M
If you like, underscores in a variable name can be specified as
dashes. The following option groups are equivalent. Both set the
size of the server's key buffer to 512MB:
[mysqld]
key_buffer_size=512M
[mysqld]
key-buffer-size=512M
A variable can be specified by writing it in full or as any
unambiguous prefix. For example, the
max_allowed_packet variable can be set for
mysql as --max_a, but not as
--max because the latter is ambiguous:
shell> mysql --max=1000000
mysql: ambiguous option '--max=1000000' (max_allowed_packet, max_join_size)
Be aware that the use of variable prefixes can cause problems in
the event that new variables are implemented for a program. A
prefix that is unambiguous now might become ambiguous in the
future.
Suffixes for specifying a value multiplier can be used when
setting a variable at server startup, but not to set the value
with SET
at runtime. On the other hand, with
SET you
can assign a variable's value using an expression, which is not
true when you set a variable at server startup. For example, the
first of the following lines is legal at server startup, but the
second is not:
shell> mysql --max_allowed_packet=16M
shell> mysql --max_allowed_packet=16*1024*1024
Conversely, the second of the following lines is legal at
runtime, but the first is not:
mysql> SET GLOBAL max_allowed_packet=16M;
mysql> SET GLOBAL max_allowed_packet=16*1024*1024;
Note
Before MySQL 4.0.2, the only syntax for setting program
variables was
--set-variable=option=value
(or
set-variable=option=value
in option files). Underscores cannot be given as dashes, and
the variable name must be specified in full. This syntax still
is recognized, but is now deprecated.
4.2.3.5. Option Defaults, Options Expecting Values, and the =
Sign
By convention, long forms of options that assign a value are
written with an equals (=) sign, like this:
shell> mysql --host=tonfisk --user=jon
For options that require a value (that is, not having a default
value), the equals sign is not required, and so the following is
also valid:
shell> mysql --host tonfisk --user jon
In both cases, the mysql client attempts to
connect to a MySQL server running on the host named
“tonfisk” using an account with the user name
“jon”.
Due to this behavior, problems can occasionally arise when no
value is provided for an option that expects one. Consider the
following example, where a user connects to a MySQL server
running on host tonfisk as user
jon:
shell> mysql --host 85.224.35.45 --user jon
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.1.45 Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> SELECT CURRENT_USER();
+----------------+
| CURRENT_USER() |
+----------------+
| jon@% |
+----------------+
1 row in set (0.00 sec)
Omitting the required value for one of these option yields an
error, such as the one shown here:
shell> mysql --host 85.224.35.45 --user
mysql: option '--user' requires an argument
In this case, mysql was unable to find a
value following the --user
option because nothing came after it on the command line.
However, if you omit the value for an option that is
not the last option to be used, you obtain
a different error that you may not be expecting:
shell> mysql --host --user jon
ERROR 2005 (HY000): Unknown MySQL server host '--user' (1)
Because mysql assumes that any string
following --host on the command
line is a host name, --host
--user is interpreted as
--host=--user, and the client
attempts to connect to a MySQL server running on a host named
“--user”.
Options having default values always require an equals sign when
assigning a value; failing to do so causes an error. For
example, the MySQL server
--log-error option has the
default value
host_name.err,
where host_name is the name of the
host on which MySQL is running. Assume that you are running
MySQL on a computer whose host name is “tonfisk”,
and consider the following invocation of
mysqld_safe:
shell> mysqld_safe &
[1] 11699
shell> 080112 12:53:40 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'.
080112 12:53:40 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var
shell>
After shutting down the server, restart it as follows:
shell> mysqld_safe --log-error &
[1] 11699
shell> 080112 12:53:40 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'.
080112 12:53:40 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var
shell>
The result is the same, since
--log-error is not followed
by anything else on the command line, and it supplies its own
default value. (The & character tells the
operating system to run MySQL in the background; it is ignored
by MySQL itself.) Now suppose that you wish to log errors to a
file named my-errors.err. You might try
starting the server with --log-error my-errors,
but this does not have the intended effect, as shown here:
shell> mysqld_safe --log-error my-errors &
[1] 31357
shell> 080111 22:53:31 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'.
080111 22:53:32 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var
080111 22:53:34 mysqld_safe mysqld from pid file /usr/local/mysql/var/tonfisk.pid ended
[1]+ Done ./mysqld_safe --log-error my-errors
The server attempted to start using
/usr/local/mysql/var/tonfisk.err as the
error log, but then shut down. Examining the last few lines of
this file shows the reason:
shell> tail /usr/local/mysql/var/tonfisk.err
080111 22:53:32 InnoDB: Started; log sequence number 0 46409
/usr/local/mysql/libexec/mysqld: Too many arguments (first extra is 'my-errors').
Use --verbose --help to get a list of available options
080111 22:53:32 [ERROR] Aborting
080111 22:53:32 InnoDB: Starting shutdown...
080111 22:53:34 InnoDB: Shutdown completed; log sequence number 0 46409
080111 22:53:34 [Note] /usr/local/mysql/libexec/mysqld: Shutdown complete
080111 22:53:34 mysqld_safe mysqld from pid file /usr/local/mysql/var/tonfisk.pid ended
Because the --log-error
option supplies a default value, you must use an equals sign to
assign a different value to it, as shown here:
shell> mysqld_safe --log-error=my-errors &
[1] 31437
shell> 080111 22:54:15 mysqld_safe Logging to '/usr/local/mysql/var/my-errors.err'.
080111 22:54:15 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var
shell>
Now the server has been started successfully, and is logging
errors to the file
/usr/local/mysql/var/my-errors.err.
Similar issues can arise when specifying option values in option
files. For example, consider a my.cnf file
that contains the following:
[mysql]
host
user
When the mysql client reads this file, these
entries are parsed as --host
--user or
--host=--user, with the result
shown here:
shell> mysql
ERROR 2005 (HY000): Unknown MySQL server host '--user' (1)
However, in option files, an equals sign is not assumed. Suppose
the my.cnf file is as shown here:
[mysql]
user jon
Trying to start mysql in this case causes a
different error:
shell> mysql
mysql: unknown option '--user jon'
A similar error would occur if you were to write host
tonfisk in the option file rather than
host=tonfisk. Instead, you must use the
equals sign:
[mysql]
user=jon
shell> mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.1.45 Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> SELECT USER();
+---------------+
| USER() |
+---------------+
| jon@localhost |
+---------------+
1 row in set (0.00 sec)
This is not the same behavior as with the command line, where
the equals sign is not required:
shell> mysql --user jon --host tonfisk
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.1.45 Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> SELECT USER();
+---------------+
| USER() |
+---------------+
| jon@tonfisk |
+---------------+
1 row in set (0.00 sec)
4.2.4. Setting Environment Variables
Environment variables can be set at the command prompt to affect
the current invocation of your command processor, or set
permanently to affect future invocations. To set a variable
permanently, you can set it in a startup file or by using the
interface provided by your system for this purpose. Consult the
documentation for your command interpreter for specific details.
Section 2.14, “Environment Variables”, lists all environment
variables that affect MySQL program operation.
To specify a value for an environment variable, use the syntax
appropriate for your command processor. For example, on Windows or
NetWare, you can set the USER variable to
specify your MySQL account name. To do so, use this syntax:
SET USER=your_name
The syntax on Unix depends on your shell. Suppose that you want to
specify the TCP/IP port number using the
MYSQL_TCP_PORT variable. Typical syntax (such
as for sh, bash,
zsh, and so on) is as follows:
MYSQL_TCP_PORT=3306
export MYSQL_TCP_PORT
The first command sets the variable, and the
export command exports the variable to the
shell environment so that its value becomes accessible to MySQL
and other processes.
For csh and tcsh, use
setenv to make the shell variable available to
the environment:
setenv MYSQL_TCP_PORT 3306
The commands to set environment variables can be executed at your
command prompt to take effect immediately, but the settings
persist only until you log out. To have the settings take effect
each time you log in, use the interface provided by your system or
place the appropriate command or commands in a startup file that
your command interpreter reads each time it starts.
On Windows, you can set environment variables using the System
Control Panel (under Advanced).
On Unix, typical shell startup files are
.bashrc or .bash_profile
for bash, or .tcshrc for
tcsh.
Suppose that your MySQL programs are installed in
/usr/local/mysql/bin and that you want to make
it easy to invoke these programs. To do this, set the value of the
PATH environment variable to include that
directory. For example, if your shell is bash,
add the following line to your .bashrc file:
PATH=${PATH}:/usr/local/mysql/bin
bash uses different startup files for login and
nonlogin shells, so you might want to add the setting to
.bashrc for login shells and to
.bash_profile for nonlogin shells to make
sure that PATH is set regardless.
If your shell is tcsh, add the following line
to your .tcshrc file:
setenv PATH ${PATH}:/usr/local/mysql/bin
If the appropriate startup file does not exist in your home
directory, create it with a text editor.
After modifying your PATH setting, open a new
console window on Windows or log in again on Unix so that the
setting goes into effect.
4.3. MySQL Server and Server-Startup Programs
This section describes mysqld, the MySQL server,
and several programs that are used to start the server.
4.3.1. mysqld — The MySQL Server
mysqld, also known as MySQL Server, is the
main program that does most of the work in a MySQL installation.
MySQL Server manages access to the MySQL data directory that
contains databases and tables. The data directory is also the
default location for other information such as log files and
status files.
When MySQL server starts, it listens for network connections
from client programs and manages access to databases on behalf
of those clients.
The mysqld program has many options that can
be specified at startup. For a complete list of options, run
this command:
shell> mysqld --verbose --help
MySQL Server also has a set of system variables that affect its
operation as it runs. System variables can be set at server
startup, and many of them can be changed at runtime to effect
dynamic server reconfiguration. MySQL Server also has a set of
status variables that provide information about its operation.
You can monitor these status variables to access runtime
performance characteristics.
For a full description of MySQL Server command options, system
variables, and status variables, see
Section 5.1, “The MySQL Server”. For information about
installing MySQL and setting up the initial configuration, see
Chapter 2, Installing and Upgrading MySQL.
4.3.2. mysqld_safe — MySQL Server Startup Script
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”.
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 Options
--help
Display a help message and exit.
--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:
*<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.
--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”.
--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 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.
--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. These options were added in MySQL 5.1.20.
--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.
--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, 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 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
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:
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
host_name.err
file in the data directory.
Sends mysqld_safe screen output to the
host_name.safe
file in the data directory.
4.3.3. mysql.server — MySQL Server Startup Script
MySQL distributions on Unix include a script named
mysql.server. It can be used on systems such
as Linux and Solaris that use System V-style run directories to
start and stop system services. It is also used by the Mac OS X
Startup Item for MySQL.
mysql.server can be found in the
support-files directory under your MySQL
installation directory or in a MySQL source distribution.
If you use the Linux server RPM package
(MySQL-server-VERSION.rpm),
the mysql.server script will be installed in
the /etc/init.d directory with the name
mysql. You need not install it manually.
See Section 2.6.1, “Installing MySQL from RPM Packages on Linux”, for more information on the
Linux RPM packages.
Some vendors provide RPM packages that install a startup script
under a different name such as mysqld.
If you install MySQL from a source distribution or using a
binary distribution format that does not install
mysql.server automatically, you can install
it manually. Instructions are provided in
Section 2.13.1.2, “Starting and Stopping MySQL Automatically”.
mysql.server reads options from the
[mysql.server] and
[mysqld] sections of option files. For
backward compatibility, it also reads
[mysql_server] sections, although you should
rename such sections to [mysql.server] when
using MySQL 5.1.
mysql.server supports the following options.
--basedir=path
The path to the MySQL installation directory.
--datadir=path
The path to the MySQL data directory.
--pid-file=file_name
The path name of the file in which the server should write
its process ID.
--service-startup-timeout=file_name
How long in seconds to wait for confirmation of server
startup. If the server does not start within this time,
mysql.server exits with an error. The
default value is 900. A value of 0 means not to wait at all
for startup. Negative values mean to wait forever (no
timeout). This option was added in MySQL 5.1.17. Before
that, a value of 900 is always used.
--use-mysqld_safe
Use mysqld_safe to start the server. This
is the default.
--use-manager
Use Instance Manager to start the server.
--user=user_name
The login user name to use for running
mysqld.
4.3.4. mysqld_multi — Manage Multiple MySQL Servers
mysqld_multi is designed to manage several
mysqld processes that listen for connections
on different Unix socket files and TCP/IP ports. It can start or
stop servers, or report their current status. The MySQL Instance
Manager is an alternative means of managing multiple servers
(see Section 4.6.10, “mysqlmanager — The MySQL Instance Manager”).
mysqld_multi searches for groups named
[mysqldN] in
my.cnf (or in the file named by the
--config-file option).
N can be any positive integer. This
number is referred to in the following discussion as the option
group number, or GNR. Group numbers
distinguish option groups from one another and are used as
arguments to mysqld_multi to specify which
servers you want to start, stop, or obtain a status report for.
Options listed in these groups are the same that you would use
in the [mysqld] group used for starting
mysqld. (See, for example,
Section 2.13.1.2, “Starting and Stopping MySQL Automatically”.) However, when using multiple
servers, it is necessary that each one use its own value for
options such as the Unix socket file and TCP/IP port number. For
more information on which options must be unique per server in a
multiple-server environment, see
Section 5.6, “Running Multiple MySQL Servers on the Same Machine”.
To invoke mysqld_multi, use the following
syntax:
shell> mysqld_multi [options] {start|stop|report} [GNR[,GNR] ...]
start, stop, and
report indicate which operation to perform.
You can perform the designated operation for a single server or
multiple servers, depending on the
GNR list that follows the option
name. If there is no list, mysqld_multi
performs the operation for all servers in the option file.
Each GNR value represents an option
group number or range of group numbers. The value should be the
number at the end of the group name in the option file. For
example, the GNR for a group named
[mysqld17] is 17. To
specify a range of numbers, separate the first and last numbers
by a dash. The GNR value
10-13 represents groups
[mysqld10] through
[mysqld13]. Multiple groups or group ranges
can be specified on the command line, separated by commas. There
must be no whitespace characters (spaces or tabs) in the
GNR list; anything after a whitespace
character is ignored.
This command starts a single server using option group
[mysqld17]:
shell> mysqld_multi start 17
This command stops several servers, using option groups
[mysqld8] and [mysqld10]
through [mysqld13]:
shell> mysqld_multi stop 8,10-13
For an example of how you might set up an option file, use this
command:
shell> mysqld_multi --example
As of MySQL 5.1.18, mysqld_multi searches for
option files as follows:
Before MySQL 5.1.18, the preceding options are not recognized.
Files in the standard locations are read, and any file named by
the
--config-file=file_name
option, if one is given. A file named by
--config-file is read only
for [mysqldN]
option groups, not the [mysqld_multi] group.
Option files read are searched for
[mysqld_multi] and
[mysqldN] option
groups. The [mysqld_multi] group can be used
for options to mysqld_multi itself.
[mysqldN] groups
can be used for options passed to specific
mysqld instances.
As of MySQL 5.1.35, the [mysqld] or
[mysqld_safe] groups can be used for common
options read by all instances of mysqld or
mysqld_safe. You can specify a
--defaults-file=file_name
option to use a different configuration file for that instance,
in which case the [mysqld] or
[mysqld_safe] groups from that file will be
used for that instance. Before MySQL 5.1.35, some versions of
mysqld_multi pass the
--no-defaults options to
instances, so these techniques are inapplicable.
mysqld_multi supports the following options.
--help
Display a help message and exit.
--config-file=file_name
As of MySQL 5.1.18, this option is deprecated. If given, it
is treated the same way as
--defaults-extra-file,
described earlier.
Before MySQL 5.1.18, this option specifies the name of an
extra option file. It affects where
mysqld_multi looks for
[mysqldN]
option groups. Without this option, all options are read
from the usual my.cnf file. The option
does not affect where mysqld_multi reads
its own options, which are always taken from the
[mysqld_multi] group in the usual
my.cnf file.
--example
Display a sample option file.
--log=file_name
Specify the name of the log file. If the file exists, log
output is appended to it.
--mysqladmin=prog_name
The mysqladmin binary to be used to stop
servers.
--mysqld=prog_name
The mysqld binary to be used. Note that
you can specify mysqld_safe as the value
for this option also. If you use
mysqld_safe to start the server, you can
include the mysqld or
ledir options in the corresponding
[mysqldN]
option group. These options indicate the name of the server
that mysqld_safe should start and the
path name of the directory where the server is located. (See
the descriptions for these options in
Section 4.3.2, “mysqld_safe — MySQL Server Startup Script”.) Example:
[mysqld38]
mysqld = mysqld-debug
ledir = /opt/local/mysql/libexec
--no-log
Print log information to stdout rather
than to the log file. By default, output goes to the log
file.
--password=password
The password of the MySQL account to use when invoking
mysqladmin. Note that the password value
is not optional for this option, unlike for other MySQL
programs.
--silent
Silent mode; disable warnings.
--tcp-ip
Connect to each MySQL server via the TCP/IP port instead of
the Unix socket file. (If a socket file is missing, the
server might still be running, but accessible only via the
TCP/IP port.) By default, connections are made using the
Unix socket file. This option affects
stop and report
operations.
--user=user_name
The user name of the MySQL account to use when invoking
mysqladmin.
--verbose
Be more verbose.
--version
Display version information and exit.
Some notes about mysqld_multi:
Most important: Before
using mysqld_multi be sure that you
understand the meanings of the options that are passed to
the mysqld servers and
why you would want to have separate
mysqld processes. Beware of the dangers
of using multiple mysqld servers with the
same data directory. Use separate data directories, unless
you know what you are doing. Starting
multiple servers with the same data directory does
not give you extra performance in a
threaded system. See Section 5.6, “Running Multiple MySQL Servers on the Same Machine”.
Important
Make sure that the data directory for each server is fully
accessible to the Unix account that the specific
mysqld process is started as.
Do not use the Unix
root account for this, unless
you know what you are doing. See
Section 5.3.5, “How to Run MySQL as a Normal User”.
Make sure that the MySQL account used for stopping the
mysqld servers (with the
mysqladmin program) has the same user
name and password for each server. Also, make sure that the
account has the SHUTDOWN
privilege. If the servers that you want to manage have
different user names or passwords for the administrative
accounts, you might want to create an account on each server
that has the same user name and password. For example, you
might set up a common multi_admin account
by executing the following commands for each server:
shell> mysql -u root -S /tmp/mysql.sock -p
Enter password:
mysql> GRANT SHUTDOWN ON *.*
-> TO 'multi_admin'@'localhost' IDENTIFIED BY 'multipass';
See Section 5.4, “The MySQL Access Privilege System”. You have to do this
for each mysqld server. Change the
connection parameters appropriately when connecting to each
one. Note that the host name part of the account name must
allow you to connect as multi_admin from
the host where you want to run
mysqld_multi.
The Unix socket file and the TCP/IP port number must be
different for every mysqld.
(Alternatively, if the host has multiple network addresses,
you can use --bind-address to
cause different servers to listen to different interfaces.)
The --pid-file option is
very important if you are using
mysqld_safe to start
mysqld (for example,
--mysqld=mysqld_safe)
Every mysqld should have its own process
ID file. The advantage of using
mysqld_safe instead of
mysqld is that
mysqld_safe monitors its
mysqld process and restarts it if the
process terminates due to a signal sent using kill
-9 or for other reasons, such as a segmentation
fault. Please note that the mysqld_safe
script might require that you start it from a certain place.
This means that you might have to change location to a
certain directory before running
mysqld_multi. If you have problems
starting, please see the mysqld_safe
script. Check especially the lines:
----------------------------------------------------------------
MY_PWD=`pwd`
# Check if we are starting this relative (for the binary release)
if test -d $MY_PWD/data/mysql -a \
-f ./share/mysql/english/errmsg.sys -a \
-x ./bin/mysqld
----------------------------------------------------------------
The test performed by these lines should be successful, or
you might encounter problems. See
Section 4.3.2, “mysqld_safe — MySQL Server Startup Script”.
You might want to use the
--user option for
mysqld, but to do this you need to run
the mysqld_multi script as the Unix
root user. Having the option in the
option file doesn't matter; you just get a warning if you
are not the superuser and the mysqld
processes are started under your own Unix account.
The following example shows how you might set up an option file
for use with mysqld_multi. The order in which
the mysqld programs are started or stopped
depends on the order in which they appear in the option file.
Group numbers need not form an unbroken sequence. The first and
fifth [mysqldN]
groups were intentionally omitted from the example to illustrate
that you can have “gaps” in the option file. This
gives you more flexibility.
# This file should probably be in your home dir (~/.my.cnf)
# or /etc/my.cnf
# Version 2.1 by Jani Tolonen
[mysqld_multi]
mysqld = /usr/local/bin/mysqld_safe
mysqladmin = /usr/local/bin/mysqladmin
user = multi_admin
password = multipass
[mysqld2]
socket = /tmp/mysql.sock2
port = 3307
pid-file = /usr/local/mysql/var2/hostname.pid2
datadir = /usr/local/mysql/var2
language = /usr/local/share/mysql/english
user = john
[mysqld3]
socket = /tmp/mysql.sock3
port = 3308
pid-file = /usr/local/mysql/var3/hostname.pid3
datadir = /usr/local/mysql/var3
language = /usr/local/share/mysql/swedish
user = monty
[mysqld4]
socket = /tmp/mysql.sock4
port = 3309
pid-file = /usr/local/mysql/var4/hostname.pid4
datadir = /usr/local/mysql/var4
language = /usr/local/share/mysql/estonia
user = tonu
[mysqld6]
socket = /tmp/mysql.sock6
port = 3311
pid-file = /usr/local/mysql/var6/hostname.pid6
datadir = /usr/local/mysql/var6
language = /usr/local/share/mysql/japanese
user = jani
See Section 4.2.3.3, “Using Option Files”.
4.4. MySQL Installation-Related Programs
The programs in this section are used when installing or upgrading
MySQL.
4.4.1. comp_err — Compile MySQL Error Message File
comp_err creates the
errmsg.sys file that is used by
mysqld to determine the error messages to
display for different error codes. comp_err
normally is run automatically when MySQL is built. It compiles
the errmsg.sys file from the plaintext file
located at sql/share/errmsg.txt in MySQL
source distributions.
comp_err also generates
mysqld_error.h,
mysqld_ername.h, and
sql_state.h header files.
For more information about how error messages are defined, see
the MySQL Internals Manual.
Invoke comp_err like this:
shell> comp_err [options]
comp_err supports the following options.
--help, -?
Display a help message and exit.
--charset=path,
-C path
The character set directory. The default is
../sql/share/charsets.
--debug=debug_options,
-# debug_options
Write a debugging log. A typical
debug_options string is
'd:t:O,file_name'.
The default is
'd:t:O,/tmp/comp_err.trace'.
--debug-info,
-T
Print some debugging information when the program exits.
--header_file=file_name,
-H file_name
The name of the error header file. The default is
mysqld_error.h.
--in_file=file_name,
-F file_name
The name of the input file. The default is
../sql/share/errmsg.txt.
--name_file=file_name,
-N file_name
The name of the error name file. The default is
mysqld_ername.h.
--out_dir=path,
-D path
The name of the output base directory. The default is
../sql/share/.
--out_file=file_name,
-O file_name
The name of the output file. The default is
errmsg.sys.
--statefile=file_name,
-S file_name
The name for the SQLSTATE header file. The default is
sql_state.h.
--version,
-V
Display version information and exit.
4.4.2. make_win_bin_dist — Package MySQL Distribution as ZIP Archive
This script is used on Windows after building a MySQL
distribution from source to create executable programs. It
packages the binaries and support files into a ZIP archive that
can be unpacked at the location where you want to install MySQL.
make_win_bin_dist is a shell script, so you
must have Cygwin installed to use it.
This program's use is subject to change. Currently, you invoke
it as follows from the root directory of your source
distribution:
shell> make_win_bin_dist [options] package_basename [copy_def ...]
The package_basename argument
provides the basename for the resulting ZIP archive. This name
will be the name of the directory that results from unpacking
the archive.
Because you might want to include files of directories from
other builds, you can instruct this script do copy them in for
you, via copy_def arguments, which of
which is of the form
relative_dest_name=source_name.
Example:
bin/mysqld-max.exe=../my-max-build/sql/release/mysqld.exe
If you specify a directory, the entire directory will be copied.
make_win_bin_dist supports the following
options.
--debug
Pack the debug binaries and produce an error if they were
not built.
--embedded
Pack the embedded server and produce an error if it was not
built. The default is to pack it if it was built.
--exe-suffix=suffix
Add a suffix to the basename of the mysql
binary. For example, a suffix of -abc
produces a binary named mysqld-abc.exe.
--no-debug
Do not pack the debug binaries even if they were built.
--no-embedded
Do not pack the embedded server even if it was built.
--only-debug
Use this option when the target for this build was
Debug, and you just want to replace the
normal binaries with debug versions (that is, do not use
separate debug directories).
4.4.3. mysqlbug — Generate Bug Report
This program enables you to generate a bug report and send it to
Sun Microsystems, Inc. It is a shell script and runs on Unix.
The normal way to report bugs is to visit
http://bugs.mysql.com/, which is the address for
our bugs database. This database is public and can be browsed
and searched by anyone. If you log in to the system, you can
enter new reports. If you have no Web access, you can generate a
bug report by using the mysqlbug script.
mysqlbug helps you generate a report by
determining much of the following information automatically, but
if something important is missing, please include it with your
message. mysqlbug can be found in the
scripts directory (source distribution) and
in the bin directory under your MySQL
installation directory (binary distribution).
Invoke mysqlbug without arguments:
shell> mysqlbug
The script will place you in an editor with a copy of the report
to be sent. Edit the lines near the beginning that indicate the
nature of the problem. Then write the file to save your changes,
quit the editor, and mysqlbug will send the
report by email.
4.4.4. mysql_fix_privilege_tables — Upgrade MySQL System Tables
Some releases of MySQL introduce changes to the structure of the
system tables in the mysql database to add
new privileges or support new features. When you update to a new
version of MySQL, you should update your system tables as well
to make sure that their structure is up to date. Otherwise,
there might be capabilities that you cannot take advantage of.
mysql_fix_privilege_tables is an older script
that previously was used to uprade the system tables in the
mysql database after a MySQL upgrade.
Before running mysql_fix_privilege_tables,
make a backup of your mysql database.
On Unix or Unix-like systems, update the system tables by
running the mysql_fix_privilege_tables
script:
shell> mysql_fix_privilege_tables
You must run this script while the server is running. It
attempts to connect to the server running on the local host as
root. If your root account
requires a password, indicate the password on the command line
like this:
shell> mysql_fix_privilege_tables --password=root_password
The mysql_fix_privilege_tables script
performs any actions necessary to convert your system tables to
the current format. You might see some Duplicate column
name warnings as it runs; you can ignore them.
After running the script, stop the server and restart it so that
any changes made to the system tables take effect.
On Windows systems, MySQL distributions include a
mysql_fix_privilege_tables.sql SQL script
that you can run using the mysql client. For
example, if your MySQL installation is located at
C:\Program Files\MySQL\MySQL Server
5.1, the commands look like this:
C:\> cd "C:\Program Files\MySQL\MySQL Server 5.1"
C:\> bin\mysql -u root -p mysql
mysql> SOURCE share/mysql_fix_privilege_tables.sql
Note
Prior to version 5.1.17, the
mysql_fix_privilege_tables.sql script is
found in the scripts directory.
The mysql command will prompt you for the
root password; enter it when prompted.
If your installation is located in some other directory, adjust
the path names appropriately.
As with the Unix procedure, you might see some
Duplicate column name warnings as
mysql processes the statements in the
mysql_fix_privilege_tables.sql script; you
can ignore them.
After running the script, stop the server and restart it.
4.4.5. mysql_install_db — Initialize MySQL Data Directory
mysql_install_db initializes the MySQL data
directory and creates the system tables that it contains, if
they do not exist.
To invoke mysql_install_db, use the following
syntax:
shell> mysql_install_db [options]
Because the MySQL server, mysqld, needs to
access the data directory when it runs later, you should either
run mysql_install_db from the same account
that will be used for running mysqld or run
it as root and use the
--user option to
indicate the user name that mysqld will run
as. It might be necessary to specify other options such as
--basedir or
--datadir if
mysql_install_db does not use the correct
locations for the installation directory or data directory. For
example:
shell> bin/mysql_install_db --user=mysql \
--basedir=/opt/mysql/mysql \
--datadir=/opt/mysql/mysql/data
mysql_install_db needs to invoke
mysqld with the
--bootstrap and
--skip-grant-tables options (see
Section 2.3.2, “Typical configure Options”). If MySQL was configured
with the
--disable-grant-options
option, --bootstrap and
--skip-grant-tables will be
disabled. To handle this, set the
MYSQLD_BOOTSTRAP environment variable to the
full path name of a server that has all options enabled.
mysql_install_db will use that server.
mysql_install_db supports the following
options, which can be specified on the command line or in the
[mysql_install_db] and (if they are common to
mysqld) [mysqld] option
file groups.
--basedir=path
The path to the MySQL installation directory.
--force
Cause mysql_install_db to run even if DNS
does not work. In that case, grant table entries that
normally use host names will use IP addresses.
--datadir=path,
--ldata=path
The path to the MySQL data directory.
--rpm
For internal use. This option is used by RPM files during
the MySQL installation process.
--skip-name-resolve
Use IP addresses rather than host names when creating grant
table entries. This option can be useful if your DNS does
not work.
--srcdir=path
For internal use. The directory under which
mysql_install_db looks for support files
such as the error message file and the file for populating
the help tables. This option was added in MySQL 5.1.14.
--user=user_name
The login user name to use for running
mysqld. Files and directories created by
mysqld will be owned by this user. You
must be root to use this option. By
default, mysqld runs using your current
login name and files and directories that it creates will be
owned by you.
--verbose
Verbose mode. Print more information about what the program
does.
--windows
For internal use. This option is used for creating Windows
distributions.
4.4.6. mysql_secure_installation — Improve MySQL Installation Security
This program enables you to improve the security of your MySQL
installation in the following ways:
You can set a password for root accounts.
You can remove root accounts that are
accessible from outside the local host.
You can remove anonymous-user accounts.
You can remove the test database, which
by default can be accessed by anonymous users.
Invoke mysql_secure_installation without
arguments:
shell> mysql_secure_installation
The script will prompt you to determine which actions to
perform.
4.4.7. mysql_tzinfo_to_sql — Load the Time Zone Tables
The mysql_tzinfo_to_sql program loads the
time zone tables in the mysql database. It is
used on systems that have a zoneinfo
database (the set of files describing time zones). Examples of
such systems are Linux, FreeBSD, Sun Solaris, and Mac OS X. One
likely location for these files is the
/usr/share/zoneinfo directory
(/usr/share/lib/zoneinfo on Solaris). If
your system does not have a zoneinfo database, you can use the
downloadable package described in
Section 9.7, “MySQL Server Time Zone Support”.
mysql_tzinfo_to_sql can be invoked several
ways:
shell> mysql_tzinfo_to_sql tz_dir
shell> mysql_tzinfo_to_sql tz_file tz_name
shell> mysql_tzinfo_to_sql --leap tz_file
For the first invocation syntax, pass the zoneinfo directory
path name to mysql_tzinfo_to_sql and send the
output into the mysql program. For example:
shell> mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root mysql
mysql_tzinfo_to_sql reads your system's time
zone files and generates SQL statements from them.
mysql processes those statements to load the
time zone tables.
The second syntax causes mysql_tzinfo_to_sql
to load a single time zone file
tz_file that corresponds to a time
zone name tz_name:
shell> mysql_tzinfo_to_sql tz_file tz_name | mysql -u root mysql
If your time zone needs to account for leap seconds, invoke
mysql_tzinfo_to_sql using the third syntax,
which initializes the leap second information.
tz_file is the name of your time zone
file:
shell> mysql_tzinfo_to_sql --leap tz_file | mysql -u root mysql
After running mysql_tzinfo_to_sql, it is best
to restart the server so that it does not continue to use any
previously cached time zone data.
4.4.8. mysql_upgrade — Check Tables for MySQL Upgrade
mysql_upgrade examines all tables in all
databases for incompatibilities with the current version of
MySQL Server. mysql_upgrade also upgrades the
system tables so that you can take advantage of new privileges
or capabilities that might have been added.
mysql_upgrade should be executed each time
you upgrade MySQL. It supersedes the older
mysql_fix_privilege_tables script, which
should no longer be used.
If a table is found to have a possible incompatibility,
mysql_upgrade performs a table check. If any
problems are found, a table repair is attempted. If the table
cannot be repaired, see Section 2.4.4, “Rebuilding or Repairing Tables or Indexes” for
manual table repair strategies.
Note
On Windows Server 2008 and Windows Vista, you must run
mysql_upgrade with administrator
privileges. You can do this by running a Command Prompt as
Administrator and running the command. Failure to do so may
result in the upgrade failing to execute correctly.
Caution
You should always back up your current MySQL installation
before performing an upgrade. See
Section 6.2, “Database Backup Methods”.
Some upgrade incompatibilities may require special handling
before you upgrade your MySQL installation and run
mysql_upgrade. See
Section 2.4.1, “Upgrading MySQL”, for instructions on determining
whether any such incompatibilities apply to your installation
and how to handle them.
To use mysql_upgrade, make sure that the
server is running, and then invoke it like this:
shell> mysql_upgrade [options]
After running mysql_upgrade, stop the server
and restart it so that any changes made to the system tables
take effect.
mysql_upgrade executes the following commands
to check and repair tables and to upgrade the system tables:
mysqlcheck --all-databases --check-upgrade --auto-repair
mysql < fix_priv_tables
mysqlcheck --all-databases --check-upgrade --fix-db-names --fix-table-names
Notes about the preceding commands:
Because mysql_upgrade invokes
mysqlcheck with the
--all-databases option,
it processes all tables in all databases, which might take a
long time to complete. Each table is locked and therefore
unavailable to other sessions while it is being processed.
Check and repair operations can be time-consuming,
particularly for large tables.
For details about what checks the
--check-upgrade option
entails, see the description of the FOR
UPGRADE option of the CHECK
TABLE statement (see
Section 12.5.2.3, “CHECK TABLE Syntax”).
fix_priv_tables represents a
script generated internally by
mysql_upgrade that contains SQL
statements to upgrade the tables in the
mysql database.
Prior to MySQL 5.1.31, mysql_upgrade does
not run the second mysqlcheck command,
which is necessary to re-encode database or table names that
contain nonalphanumeric characters. (They still appear after
the upgrade with the #mysql50# prefix
described in Section 8.2.3, “Mapping of Identifiers to File Names”.) If you
have such database or table names, execute the second
mysqlcheck command manually after
executing mysql_upgrade.
All checked and repaired tables are marked with the current
MySQL version number. This ensures that next time you run
mysql_upgrade with the same version of the
server, it can tell whether there is any need to check or repair
the table again.
mysql_upgrade also saves the MySQL version
number in a file named mysql_upgrade_info
in the data directory. This is used to quickly check whether all
tables have been checked for this release so that table-checking
can be skipped. To ignore this file and perform the check
regardless, use the
--force option.
If you install MySQL from RPM packages on Linux, you must
install the server and client RPMs.
mysql_upgrade is included in the server RPM
but requires the client RPM because the latter includes
mysqlcheck. (See
Section 2.6.1, “Installing MySQL from RPM Packages on Linux”.)
In MySQL 5.1.7, mysql_upgrade was added as a
shell script and worked only for Unix systems. As of MySQL
5.1.10, mysql_upgrade is an executable binary
and is available on all systems.
mysql_upgrade supports the following options,
which can be specified on the command line or in the
[mysql_upgrade] and
[client] option file groups. Other options
are passed to mysqlcheck. For example, it
might be necessary to specify the
--password[=password]
option. mysql_upgrade also supports the
options for processing option files described at
Section 4.2.3.3.1, “Command-Line Options that Affect Option-File Handling”.
--help
Display a short help message and exit.
--basedir=path
The path to the MySQL installation directory. This option is
accepted for backward compatibility but ignored.
--datadir=path
The path to the data directory. This option is accepted for
backward compatibility but ignored.
--debug-check
Print some debugging information when the program exits.
This option was added in MySQL 5.1.21.
--debug-info,
-T
Print debugging information and memory and CPU usage
statistics when the program exits. This option was added in
MySQL 5.1.21.
--force
Ignore the mysql_upgrade_info file and
force execution of mysqlcheck even if
mysql_upgrade has already been executed
for the current version of MySQL.
--tmpdir=path,
-t path
The path name of the directory to use for creating temporary
files. This option was added in MySQL 5.1.25.
--user=user_name,
-u user_name
The MySQL user name to use when connecting to the server.
The default user name is root.
--verbose
Verbose mode. Print more information about what the program
does.
--write-binlog
Cause binary logging to be enabled while
mysql_upgrade runs. This is the default
behavior; to disable binary logging during the upgrade, use
the inverse of this option (that is, start the program with
--skip-write-binlog).
This option was introduced in MySQL 5.1.40.
4.5. MySQL Client Programs
This section describes client programs that connect to the MySQL
server.
4.5.1. mysql — The MySQL Command-Line Tool
mysql is a simple SQL shell (with GNU
readline capabilities). It supports
interactive and noninteractive use. When used interactively,
query results are presented in an ASCII-table format. When used
noninteractively (for example, as a filter), the result is
presented in tab-separated format. The output format can be
changed using command options.
If you have problems due to insufficient memory for large result
sets, use the --quick option. This
forces mysql to retrieve results from the
server a row at a time rather than retrieving the entire result
set and buffering it in memory before displaying it. This is
done by returning the result set using the
mysql_use_result() C API
function in the client/server library rather than
mysql_store_result().
Using mysql is very easy. Invoke it from the
prompt of your command interpreter as follows:
shell> mysql db_name
Or:
shell> mysql --user=user_name --password=your_password db_name
Then type an SQL statement, end it with
“;”, \g, or
\G and press Enter.
As of MySQL 5.1.10, typing Control-C causes
mysql to attempt to kill the current
statement. If this cannot be done, or Control-C is typed again
before the statement is killed, mysql exits.
Previously, Control-C caused mysql to exit in
all cases.
You can execute SQL statements in a script file (batch file)
like this:
shell> mysql db_name < script.sql > output.tab
mysql supports the following options, which
can be specified on the command line or in the
[mysql] and [client]
option file groups. mysql also supports the
options for processing option files described at
Section 4.2.3.3.1, “Command-Line Options that Affect Option-File Handling”.
--help, -?
Display a help message and exit.
--auto-rehash
Enable automatic rehashing. This option is on by default,
which enables database, table, and column name completion.
Use
--disable-auto-rehash
to disable rehashing. That causes mysql
to start faster, but you must issue the
rehash command if you want to use name
completion.
To complete a name, enter the first part and press Tab. If
the name is unambiguous, mysql completes
it. Otherwise, you can press Tab again to see the possible
names that begin with what you have typed so far. Completion
does not occur if there is no default database.
--batch, -B
Print results using tab as the column separator, with each
row on a new line. With this option,
mysql does not use the history file.
Batch mode results in nontabular output format and escaping
of special characters. Escaping may be disabled by using raw
mode; see the description for the
--raw option.
--character-sets-dir=path
The directory where character sets are installed. See
Section 9.2, “The Character Set Used for Data and Sorting”.
--column-names
Write column names in results.
--column-type-info,
-m
Display result set metadata. This option was added in MySQL
5.1.14. (Before that, use
--debug-info.) The
-m short option was added in MySQL 5.1.21.
--comments,
-c
Whether to preserve comments in statements sent to the
server. The default is --skip-comments (discard comments),
enable with --comments (preserve comments). This option was
added in MySQL 5.1.23.
--compress,
-C
Compress all information sent between the client and the
server if both support compression.
--database=db_name,
-D db_name
The database to use. This is useful primarily in an option
file.
--debug[=debug_options],
-#
[debug_options]
Write a debugging log. A typical
debug_options string is
'd:t:o,file_name'.
The default is 'd:t:o,/tmp/mysql.trace'.
--debug-check
Print some debugging information when the program exits.
This option was added in MySQL 5.1.21.
--debug-info,
-T
Before MySQL 5.1.14, this option prints debugging
information and memory and CPU usage statistics when the
program exits, and also causes display of result set
metadata during execution. As of MySQL 5.1.14, use
--column-type-info to display
result set metadata.
--default-character-set=charset_name
Use charset_name as the default
character set for the client and connection.
A common issue that can occur when the operating system uses
utf8 or another multi-byte character set
is that output from the mysql client is
formatted incorrectly, due to the fact that the MySQL client
uses the latin1 character set by default.
You can usually fix such issues by using this option to
force the client to use the system character set instead.
See Section 9.2, “The Character Set Used for Data and Sorting”, for more
information.
--delimiter=str
Set the statement delimiter. The default is the semicolon
character (“;”).
--disable-named-commands
Disable named commands. Use the \* form
only, or use named commands only at the beginning of a line
ending with a semicolon
(“;”).
mysql starts with this option
enabled by default. However, even with
this option, long-format commands still work from the first
line. See Section 4.5.1.2, “mysql Commands”.
--execute=statement,
-e statement
Execute the statement and quit. The default output format is
like that produced with
--batch. See
Section 4.2.3.1, “Using Options on the Command Line”, for some examples.
--force, -f
Continue even if an SQL error occurs.
--host=host_name,
-h host_name
Connect to the MySQL server on the given host.
--html, -H
Produce HTML output.
--ignore-spaces,
-i
Ignore spaces after function names. The effect of this is
described in the discussion for the
IGNORE_SPACE SQL mode (see
Section 5.1.8, “Server SQL Modes”).
--line-numbers
Write line numbers for errors. Disable this with
--skip-line-numbers.
--local-infile[={0|1}]
Enable or disable LOCAL capability for
LOAD DATA
INFILE. With no value, the option enables
LOCAL. The option may be given as
--local-infile=0 or
--local-infile=1 to explicitly
disable or enable LOCAL. Enabling
LOCAL has no effect if the server does
not also support it.
MySQL Enterprise
For expert advice on the security implications of enabling
LOCAL, subscribe to the MySQL
Enterprise Monitor. For more information, see
http://www.mysql.com/products/enterprise/advisors.html.
--named-commands,
-G
Enable named mysql commands. Long-format
commands are allowed, not just short-format commands. For
example, quit and \q
both are recognized. Use
--skip-named-commands
to disable named commands. See
Section 4.5.1.2, “mysql Commands”.
--no-auto-rehash,
-A
This has the same effect as
-skip-auto-rehash.
See the description for
--auto-rehash.
--no-beep, -b
Do not beep when errors occur.
--no-named-commands,
-g
Deprecated, use
--disable-named-commands
instead.
--no-pager
Deprecated form of
--skip-pager.
See the --pager option.
--no-tee
Do not copy output to a file.
Section 4.5.1.2, “mysql Commands”, discusses tee files
further.
--one-database,
-o
Ignore statements except those for the default database
named on the command line. This is useful for skipping
updates to other databases in the binary log.
--pager[=command]
Use the given command for paging query output. If the
command is omitted, the default pager is the value of your
PAGER environment variable. Valid pagers
are less, more,
cat [> filename], and so forth. This
option works only on Unix and only in interactive mode. To
disable paging, use
--skip-pager.
Section 4.5.1.2, “mysql Commands”, discusses output paging
further.
--password[=password],
-p[password]
The password to use when connecting to the server. If you
use the short option form (-p), you
cannot have a space between the option
and the password. If you omit the
password value following the
--password or
-p option on the command line,
mysql prompts for one.
Specifying a password on the command line should be
considered insecure. See
Section 5.5.6.2, “End-User Guidelines for Password Security”. You can use an
option file to avoid giving the password on the command
line.
--pipe, -W
On Windows, connect to the server via a named pipe. This
option applies only if the server supports named-pipe
connections.
--port=port_num,
-P port_num
The TCP/IP port number to use for the connection.
--prompt=format_str
Set the prompt to the specified format. The default is
mysql>. The special sequences that the
prompt can contain are described in
Section 4.5.1.2, “mysql Commands”.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The connection protocol to use for connecting to the server.
It is useful when the other connection parameters normally
would cause a protocol to be used other than the one you
want. For details on the allowable values, see
Section 4.2.2, “Connecting to the MySQL Server”.
--quick, -q
Do not cache each query result, print each row as it is
received. This may slow down the server if the output is
suspended. With this option, mysql does
not use the history file.
--raw, -r
For tabular output, the “boxing” around columns
enables one column value to be distinguished from another.
For nontabular output (such as is produced in batch mode or
when the --batch or
--silent option is given),
special characters are escaped in the output so they can be
identified easily. Newline, tab, NUL, and
backslash are written as \n,
\t, \0, and
\\. The
--raw option disables this
character escaping.
The following example demonstrates tabular versus nontabular
output and the use of raw mode to disable escaping:
% mysql
mysql> SELECT CHAR(92);
+----------+
| CHAR(92) |
+----------+
| \ |
+----------+
% mysql -s
mysql> SELECT CHAR(92);
CHAR(92)
\\
% mysql -s -r
mysql> SELECT CHAR(92);
CHAR(92)
\
--reconnect
If the connection to the server is lost, automatically try
to reconnect. A single reconnect attempt is made each time
the connection is lost. To suppress reconnection behavior,
use
--skip-reconnect.
--safe-updates,
--i-am-a-dummy,
-U
Allow only those UPDATE and
DELETE statements that
specify which rows to modify by using key values. If you
have set this option in an option file, you can override it
by using --safe-updates on the
command line. See Section 4.5.1.5, “mysql Tips”, for more
information about this option.
--secure-auth
Do not send passwords to the server in old (pre-4.1.1)
format. This prevents connections except for servers that
use the newer password format.
MySQL Enterprise
For expert advice on database security, subscribe to the
MySQL Enterprise Monitor. For more information, see
http://www.mysql.com/products/enterprise/advisors.html.
--show-warnings
Cause warnings to be shown after each statement if there are
any. This option applies to interactive and batch mode.
--sigint-ignore
Ignore SIGINT signals (typically the
result of typing Control-C).
--silent, -s
Silent mode. Produce less output. This option can be given
multiple times to produce less and less output.
This option results in nontabular output format and escaping
of special characters. Escaping may be disabled by using raw
mode; see the description for the
--raw option.
--skip-column-names,
-N
Do not write column names in results.
--skip-line-numbers,
-L
Do not write line numbers for errors. Useful when you want
to compare result files that include error messages.
--socket=path,
-S path
For connections to localhost, the Unix
socket file to use, or, on Windows, the name of the named
pipe to use.
--ssl*
Options that begin with
--ssl specify whether to
connect to the server via SSL and indicate where to find SSL
keys and certificates. See Section 5.5.7.3, “SSL Command Options”.
--table, -t
Display output in table format. This is the default for
interactive use, but can be used to produce table output in
batch mode.
--tee=file_name
Append a copy of output to the given file. This option works
only in interactive mode. Section 4.5.1.2, “mysql Commands”,
discusses tee files further.
--unbuffered,
-n
Flush the buffer after each query.
--user=user_name,
-u user_name
The MySQL user name to use when connecting to the server.
--verbose, -v
Verbose mode. Produce more output about what the program
does. This option can be given multiple times to produce
more and more output. (For example, -v -v
-v produces table output format even in batch
mode.)
--version, -V
Display version information and exit.
--vertical,
-E
Print query output rows vertically (one line per column
value). Without this option, you can specify vertical output
for individual statements by terminating them with
\G.
--wait, -w
If the connection cannot be established, wait and retry
instead of aborting.
--xml, -X
Produce XML output.
Note
Prior to MySQL 5.1.12, there was no differentiation in the
output when using this option between columns containing
the NULL value and columns containing
the string literal 'NULL'; both were
represented as
<field name="column_name">NULL</field>
Beginning with MySQL 5.1.12, the output when
--xml is used with
mysql matches that of mysqldump
--xml. See
Section 4.5.4, “mysqldump — A Database Backup Program” for details.
Beginning with MySQL 5.1.18, the XML output also uses an XML
namespace, as shown here:
shell> mysql --xml -uroot -e "SHOW VARIABLES LIKE 'version%'"
<?xml version="1.0"?>
<resultset statement="SHOW VARIABLES LIKE 'version%'" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<row>
<field name="Variable_name">version</field>
<field name="Value">5.0.40-debug</field>
</row>
<row>
<field name="Variable_name">version_comment</field>
<field name="Value">Source distribution</field>
</row>
<row>
<field name="Variable_name">version_compile_machine</field>
<field name="Value">i686</field>
</row>
<row>
<field name="Variable_name">version_compile_os</field>
<field name="Value">suse-linux-gnu</field>
</row>
</resultset>
(See Bug#25946.)
You can also set the following variables by using
--var_name=value.
The --set-variable format is deprecated.
connect_timeout
The number of seconds before connection timeout. (Default
value is 0.)
max_allowed_packet
The maximum packet length to send to or receive from the
server. (Default value is 16MB.)
max_join_size
The automatic limit for rows in a join when using
--safe-updates. (Default value
is 1,000,000.)
net_buffer_length
The buffer size for TCP/IP and socket communication.
(Default value is 16KB.)
select_limit
The automatic limit for
SELECT statements when using
--safe-updates. (Default value
is 1,000.)
On Unix, the mysql client writes a record of
executed statements to a history file. By default, this file is
named .mysql_history and is created in your
home directory. To specify a different file, set the value of
the MYSQL_HISTFILE environment variable.
The .mysql_history should be protected with
a restrictive access mode because sensitive information might be
written to it, such as the text of SQL statements that contain
passwords. See Section 5.5.6.2, “End-User Guidelines for Password Security”.
If you do not want to maintain a history file, first remove
.mysql_history if it exists, and then use
either of the following techniques:
Set the MYSQL_HISTFILE variable to
/dev/null. To cause this setting to
take effect each time you log in, put the setting in one of
your shell's startup files.
Create .mysql_history as a symbolic
link to /dev/null:
shell> ln -s /dev/null $HOME/.mysql_history
You need do this only once.
mysql sends each SQL statement that you issue
to the server to be executed. There is also a set of commands
that mysql itself interprets. For a list of
these commands, type help or
\h at the mysql>
prompt:
mysql> help
List of all MySQL commands:
Note that all text commands must be first on line and end with ';'
? (\?) Synonym for `help'.
clear (\c) Clear command.
connect (\r) Reconnect to the server. Optional arguments are db and host.
delimiter (\d) Set statement delimiter.
edit (\e) Edit command with $EDITOR.
ego (\G) Send command to mysql server, display result vertically.
exit (\q) Exit mysql. Same as quit.
go (\g) Send command to mysql server.
help (\h) Display this help.
nopager (\n) Disable pager, print to stdout.
notee (\t) Don't write into outfile.
pager (\P) Set PAGER [to_pager]. Print the query results via PAGER.
print (\p) Print current command.
prompt (\R) Change your mysql prompt.
quit (\q) Quit mysql.
rehash (\#) Rebuild completion hash.
source (\.) Execute an SQL script file. Takes a file name as an argument.
status (\s) Get status information from the server.
system (\!) Execute a system shell command.
tee (\T) Set outfile [to_outfile]. Append everything into given
outfile.
use (\u) Use another database. Takes database name as argument.
charset (\C) Switch to another charset. Might be needed for processing
binlog with multi-byte charsets.
warnings (\W) Show warnings after every statement.
nowarning (\w) Don't show warnings after every statement.
For server side help, type 'help contents'
Each command has both a long and short form. The long form is
not case sensitive; the short form is. The long form can be
followed by an optional semicolon terminator, but the short form
should not.
The use of short-form commands within multi-line /* ...
*/ comments is not supported.
help [arg],
\h [arg],
\? [arg],
? [arg]
Display a help message listing the available
mysql commands.
If you provide an argument to the help
command, mysql uses it as a search string
to access server-side help from the contents of the MySQL
Reference Manual. For more information, see
Section 4.5.1.3, “mysql Server-Side Help”.
charset
charset_name,
\C
charset_name
Change the default character set and issue a SET
NAMES statement. This enables the character set to
remain synchronized on the client and server if
mysql is run with auto-reconnect enabled
(which is not recommended), because the specified character
set is used for reconnects. This command was added in MySQL
5.1.7.
clear, \c
Clear the current input. Use this if you change your mind
about executing the statement that you are entering.
connect [db_name
host_name]],
\r [db_name
host_name]]
Reconnect to the server. The optional database name and host
name arguments may be given to specify the default database
or the host where the server is running. If omitted, the
current values are used.
delimiter str,
\d str
Change the string that mysql interprets
as the separator between SQL statements. The default is the
semicolon character (“;”).
The delimiter can be specified as an unquoted or quoted
argument. Quoting can be done with either single quote
(') or douple quote
(") characters. To include a quote within
a quoted string, either quote the string with the other
quote character or escape the quote with a backslash
(“\”) character. Backslash
should be avoided outside of quoted strings because it is
the escape character for MySQL. For an unquoted argument,
the delmiter is read up to the first space or end of line.
For a quoted argument, the delimiter is read up to the
matching quote on the line.
When the delimiter recognized by mysql is
set to something other than the default of
“;”, instances of that
character are sent to the server without interpretation.
However, the server itself still interprets
“;” as a statement delimiter
and processes statements accordingly. This behavior on the
server side comes into play for multiple-statement execution
(see Section 21.9.12, “C API Support for Multiple Statement Execution”), and for
parsing the body of stored procedures and functions,
triggers, and events (see
Section 19.1, “Defining Stored Programs”).
edit, \e
Edit the current input statement. mysql
checks the values of the EDITOR and
VISUAL environment variables to determine
which editor to use. The default editor is
vi if neither variable is set.
The edit command works only in Unix.
ego, \G
Send the current statement to the server to be executed and
display the result using vertical format.
exit, \q
Exit mysql.
go, \g
Send the current statement to the server to be executed.
nopager, \n
Disable output paging. See the description for
pager.
The nopager command works only in Unix.
notee, \t
Disable output copying to the tee file. See the description
for tee.
nowarning, \w
Enable display of warnings after each statement.
pager
[command], \P
[command]
Enable output paging. By using the
--pager option when you invoke
mysql, it is possible to browse or search
query results in interactive mode with Unix programs such as
less, more, or any
other similar program. If you specify no value for the
option, mysql checks the value of the
PAGER environment variable and sets the
pager to that. Pager functionality works only in interactive
mode.
Output paging can be enabled interactively with the
pager command and disabled with
nopager. The command takes an optional
argument; if given, the paging program is set to that. With
no argument, the pager is set to the pager that was set on
the command line, or stdout if no pager
was specified.
Output paging works only in Unix because it uses the
popen() function, which does not exist on
Windows. For Windows, the tee option can
be used instead to save query output, although it is not as
convenient as pager for browsing output
in some situations.
print, \p
Print the current input statement without executing it.
prompt [str],
\R [str]
Reconfigure the mysql prompt to the given
string. The special character sequences that can be used in
the prompt are described later in this section.
If you specify the prompt command with no
argument, mysql resets the prompt to the
default of mysql>.
quit, \q
Exit mysql.
rehash, \#
Rebuild the completion hash that enables database, table,
and column name completion while you are entering
statements. (See the description for the
--auto-rehash option.)
source
file_name, \.
file_name
Read the named file and executes the statements contained
therein. On Windows, you can specify path name separators as
/ or \\.
status, \s
Provide status information about the connection and the
server you are using. If you are running in
--safe-updates mode,
status also prints the values for the
mysql variables that affect your queries.
system
command, \!
command
Execute the given command using your default command
interpreter.
The system command works only in Unix.
tee
[file_name],
\T [file_name]
By using the --tee option when
you invoke mysql, you can log statements
and their output. All the data displayed on the screen is
appended into a given file. This can be very useful for
debugging purposes also. mysql flushes
results to the file after each statement, just before it
prints its next prompt. Tee functionality works only in
interactive mode.
You can enable this feature interactively with the
tee command. Without a parameter, the
previous file is used. The tee file can
be disabled with the notee command.
Executing tee again re-enables logging.
use db_name,
\u db_name
Use db_name as the default
database.
warnings, \W
Enable display of warnings after each statement (if there
are any).
Here are a few tips about the pager command:
You can use it to write to a file and the results go only to
the file:
mysql> pager cat > /tmp/log.txt
You can also pass any options for the program that you want
to use as your pager:
mysql> pager less -n -i -S
In the preceding example, note the -S
option. You may find it very useful for browsing wide query
results. Sometimes a very wide result set is difficult to
read on the screen. The -S option to
less can make the result set much more
readable because you can scroll it horizontally using the
left-arrow and right-arrow keys. You can also use
-S interactively within
less to switch the horizontal-browse mode
on and off. For more information, read the
less manual page:
shell> man less
The -F and -X options may
be used with less to cause it to exit if
output fits on one screen, which is convenient when no
scrolling is necessary:
mysql> pager less -n -i -S -F -X
You can specify very complex pager commands for handling
query output:
mysql> pager cat | tee /dr1/tmp/res.txt \
| tee /dr2/tmp/res2.txt | less -n -i -S
In this example, the command would send query results to two
files in two different directories on two different file
systems mounted on /dr1 and
/dr2, yet still display the results
onscreen via less.
You can also combine the tee and
pager functions. Have a
tee file enabled and pager
set to less, and you are able to browse the
results using the less program and still have
everything appended into a file the same time. The difference
between the Unix tee used with the
pager command and the
mysql built-in tee command
is that the built-in tee works even if you do
not have the Unix tee available. The built-in
tee also logs everything that is printed on
the screen, whereas the Unix tee used with
pager does not log quite that much.
Additionally, tee file logging can be turned
on and off interactively from within mysql.
This is useful when you want to log some queries to a file, but
not others.
The prompt command reconfigures the default
mysql> prompt. The string for defining the
prompt can contain the following special sequences.
You can set the prompt in several ways:
Use an environment variable. You can
set the MYSQL_PS1 environment variable to
a prompt string. For example:
shell> export MYSQL_PS1="(\u@\h) [\d]> "
Use a command-line option. You can set
the --prompt option on the
command line to mysql. For example:
shell> mysql --prompt="(\u@\h) [\d]> "
(user@host) [database]>
Use an option file. You can set the
prompt option in the
[mysql] group of any MySQL option file,
such as /etc/my.cnf or the
.my.cnf file in your home directory.
For example:
[mysql]
prompt=(\\u@\\h) [\\d]>\\_
In this example, note that the backslashes are doubled. If
you set the prompt using the prompt
option in an option file, it is advisable to double the
backslashes when using the special prompt options. There is
some overlap in the set of allowable prompt options and the
set of special escape sequences that are recognized in
option files. (The rules for escape sequences in option
files are listed in Section 4.2.3.3, “Using Option Files”.) The
overlap may cause you problems if you use single
backslashes. For example, \s is
interpreted as a space rather than as the current seconds
value. The following example shows how to define a prompt
within an option file to include the current time in
HH:MM:SS> format:
[mysql]
prompt="\\r:\\m:\\s> "
Set the prompt interactively. You can
change your prompt interactively by using the
prompt (or \R)
command. For example:
mysql> prompt (\u@\h) [\d]>\_
PROMPT set to '(\u@\h) [\d]>\_'
(user@host) [database]>
(user@host) [database]> prompt
Returning to default PROMPT of mysql>
mysql>
4.5.1.3. mysql Server-Side Helpmysql> help search_string
If you provide an argument to the help
command, mysql uses it as a search string to
access server-side help from the contents of the MySQL Reference
Manual. The proper operation of this command requires that the
help tables in the mysql database be
initialized with help topic information (see
Section 5.1.9, “Server-Side Help”).
If there is no match for the search string, the search fails:
mysql> help me
Nothing found
Please try to run 'help contents' for a list of all accessible topics
Use help contents to see a list of the help
categories:
mysql> help contents
You asked for help about help category: "Contents"
For more information, type 'help <item>', where <item> is one of the
following categories:
Account Management
Administration
Data Definition
Data Manipulation
Data Types
Functions
Functions and Modifiers for Use with GROUP BY
Geographic Features
Language Structure
Plugins
Storage Engines
Stored Routines
Table Maintenance
Transactions
Triggers
If the search string matches multiple items,
mysql shows a list of matching topics:
mysql> help logs
Many help items for your request exist.
To make a more specific request, please type 'help <item>',
where <item> is one of the following topics:
SHOW
SHOW BINARY LOGS
SHOW ENGINE
SHOW LOGS
Use a topic as the search string to see the help entry for that
topic:
mysql> help show binary logs
Name: 'SHOW BINARY LOGS'
Description:
Syntax:
SHOW BINARY LOGS
SHOW MASTER LOGS
Lists the binary log files on the server. This statement is used as
part of the procedure described in [purge-binary-logs], that shows how
to determine which logs can be purged.
mysql> SHOW BINARY LOGS;
+---------------+-----------+
| Log_name | File_size |
+---------------+-----------+
| binlog.000015 | 724935 |
| binlog.000016 | 733481 |
+---------------+-----------+
4.5.1.4. Executing SQL Statements from a Text File
The mysql client typically is used
interactively, like this:
shell> mysql db_name
However, it is also possible to put your SQL statements in a
file and then tell mysql to read its input
from that file. To do so, create a text file
text_file that contains the
statements you wish to execute. Then invoke
mysql as shown here:
shell> mysql db_name < text_file
If you place a USE
db_name statement as the
first statement in the file, it is unnecessary to specify the
database name on the command line:
shell> mysql < text_file
If you are already running mysql, you can
execute an SQL script file using the source
command or \. command:
mysql> source file_name
mysql> \. file_name
Sometimes you may want your script to display progress
information to the user. For this you can insert statements like
this:
SELECT '<info_to_display>' AS ' ';
The statement shown outputs
<info_to_display>.
You can also invoke mysql with the
--verbose option, which causes
each statement to be displayed before the result that it
produces.
As of MySQL 5.1.23, mysql ignores Unicode
byte order mark (BOM) characters at the beginning of input
files. Previously, it read them and sent them to the server,
resulting in a syntax error. Presence of a BOM does not cause
mysql to change its default character set. To
do that, invoke mysql with an option such as
--default-character-set=utf8.
For more information about batch mode, see
Section 3.5, “Using mysql in Batch Mode”.
This section describes some techniques that can help you use
mysql more effectively.
4.5.1.5.1. Displaying Query Results Vertically
Some query results are much more readable when displayed
vertically, instead of in the usual horizontal table format.
Queries can be displayed vertically by terminating the query
with \G instead of a semicolon. For example, longer text
values that include newlines often are much easier to read
with vertical output:
mysql> SELECT * FROM mails WHERE LENGTH(txt) < 300 LIMIT 300,1\G
*************************** 1. row ***************************
msg_nro: 3068
date: 2000-03-01 23:29:50
time_zone: +0200
mail_from: Monty
reply: monty@no.spam.com
mail_to: "Thimble Smith" <tim@no.spam.com>
sbj: UTF-8
txt: >>>>> "Thimble" == Thimble Smith writes:
Thimble> Hi. I think this is a good idea. Is anyone familiar
Thimble> with UTF-8 or Unicode? Otherwise, I'll put this on my
Thimble> TODO list and see what happens.
Yes, please do that.
Regards,
Monty
file: inbox-jani-1
hash: 190402944
1 row in set (0.09 sec)
For beginners, a useful startup option is
--safe-updates (or
--i-am-a-dummy,
which has the same effect). It is helpful for cases when you
might have issued a DELETE FROM
tbl_name statement but
forgotten the WHERE clause. Normally, such
a statement deletes all rows from the table. With
--safe-updates, you can delete
rows only by specifying the key values that identify them.
This helps prevent accidents.
When you use the --safe-updates
option, mysql issues the following
statement when it connects to the MySQL server:
SET sql_safe_updates=1, sql_select_limit=1000, sql_max_join_size=1000000;
See Section 5.1.5, “Session System Variables”.
The SET
statement has the following effects:
You are not allowed to execute an
UPDATE or
DELETE statement unless you
specify a key constraint in the WHERE
clause or provide a LIMIT clause (or
both). For example:
UPDATE tbl_name SET not_key_column=val WHERE key_column=val;
UPDATE tbl_name SET not_key_column=val LIMIT 1;
The server limits all large
SELECT results to 1,000
rows unless the statement includes a
LIMIT clause.
The server aborts multiple-table
SELECT statements that
probably need to examine more than 1,000,000 row
combinations.
To specify limits different from 1,000 and 1,000,000, you can
override the defaults by using the
--select_limit and
--max_join_size options:
shell> mysql --safe-updates --select_limit=500 --max_join_size=10000
4.5.1.5.3. Disabling mysql Auto-Reconnect
If the mysql client loses its connection to
the server while sending a statement, it immediately and
automatically tries to reconnect once to the server and send
the statement again. However, even if mysql
succeeds in reconnecting, your first connection has ended and
all your previous session objects and settings are lost:
temporary tables, the autocommit mode, and user-defined and
session variables. Also, any current transaction rolls back.
This behavior may be dangerous for you, as in the following
example where the server was shut down and restarted between
the first and second statements without you knowing it:
mysql> SET @a=1;
Query OK, 0 rows affected (0.05 sec)
mysql> INSERT INTO t VALUES(@a);
ERROR 2006: MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 1
Current database: test
Query OK, 1 row affected (1.30 sec)
mysql> SELECT * FROM t;
+------+
| a |
+------+
| NULL |
+------+
1 row in set (0.05 sec)
The @a user variable has been lost with the
connection, and after the reconnection it is undefined. If it
is important to have mysql terminate with
an error if the connection has been lost, you can start the
mysql client with the
--skip-reconnect
option.
For more information about auto-reconnect and its effect on
state information when a reconnection occurs, see
Section 21.9.11, “Controlling Automatic Reconnection Behavior”.
4.5.2. mysqladmin — Client for Administering a MySQL Server
mysqladmin is a client for performing
administrative operations. You can use it to check the server's
configuration and current status, to create and drop databases,
and more.
Invoke mysqladmin like this:
shell> mysqladmin [options] command [command-arg] [command [command-arg]] ...
mysqladmin supports the following commands.
Some of the commands take an argument following the command
name.
create db_name
Create a new database named
db_name.
debug
Tell the server to write debug information to the error log.
Beginning with MySQL 5.1.12, this includes information about
the Event Scheduler. See
Section 19.4.5, “Event Scheduler Status”.
drop db_name
Delete the database named db_name
and all its tables.
extended-status
Display the server status variables and their values.
MySQL Enterprise
For expert advice on using server status variables,
subscribe to the MySQL Enterprise Monitor. For more
information, see
http://www.mysql.com/products/enterprise/advisors.html.
flush-hosts
Flush all information in the host cache.
flush-logs
Flush all logs.
flush-privileges
Reload the grant tables (same as reload).
flush-status
Clear status variables.
flush-tables
Flush all tables.
flush-threads
Flush the thread cache.
kill
id,id,...
Kill server threads. If multiple thread ID values are given,
there must be no spaces in the list.
old-password
new-password
This is like the password command but
stores the password using the old (pre-4.1) password-hashing
format. (See Section 5.5.6.3, “Password Hashing in MySQL”.)
MySQL Enterprise
For expert advice on the security implications of using
the old-password command, subscribe to
the MySQL Enterprise Monitor. For more information, see
http://www.mysql.com/products/enterprise/advisors.html.
password
new-password
Set a new password. This changes the password to
new-password for the account that
you use with mysqladmin for connecting to
the server. Thus, the next time you invoke
mysqladmin (or any other client program)
using the same account, you will need to specify the new
password.
If the new-password value
contains spaces or other characters that are special to your
command interpreter, you need to enclose it within quotes.
On Windows, be sure to use double quotes rather than single
quotes; single quotes are not stripped from the password,
but rather are interpreted as part of the password. For
example:
shell> mysqladmin password "my new password"
Caution
Do not use this command used if the server was started
with the
--skip-grant-tables option.
No password change will be applied. This is true even if
you precede the password command with
flush-privileges on the same command
line to re-enable the grant tables because the flush
operation occurs after you connect. However, you can use
mysqladmin flush-privileges to
re-enable the grant table and then use a separate
mysqladmin password command to change
the password.
ping
Check whether the server is alive. The return status from
mysqladmin is 0 if the server is running,
1 if it is not. This is 0 even in case of an error such as
Access denied, because this means that
the server is running but refused the connection, which is
different from the server not running.
processlist
Show a list of active server threads. This is like the
output of the SHOW
PROCESSLIST statement. If the
--verbose option is
given, the output is like that of
SHOW FULL
PROCESSLIST. (See
Section 12.5.5.31, “SHOW PROCESSLIST Syntax”.)
reload
Reload the grant tables.
refresh
Flush all tables and close and open log files.
shutdown
Stop the server.
start-slave
Start replication on a slave server.
status
Display a short server status message.
stop-slave
Stop replication on a slave server.
variables
Display the server system variables and their values.
MySQL Enterprise
For expert advice on using server system variables,
subscribe to the MySQL Enterprise Monitor. For more
information, see
http://www.mysql.com/products/enterprise/advisors.html.
version
Display version information from the server.
All commands can be shortened to any unique prefix. For example:
shell> mysqladmin proc stat
+----+-------+-----------+----+---------+------+-------+------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+-------+-----------+----+---------+------+-------+------------------+
| 51 | monty | localhost | | Query | 0 | | show processlist |
+----+-------+-----------+----+---------+------+-------+------------------+
Uptime: 1473624 Threads: 1 Questions: 39487
Slow queries: 0 Opens: 541 Flush tables: 1
Open tables: 19 Queries per second avg: 0.0268
The mysqladmin status command result displays
the following values:
Uptime
The number of seconds the MySQL server has been running.
Threads
The number of active threads (clients).
Questions
The number of questions (queries) from clients since the
server was started.
Slow queries
The number of queries that have taken more than
long_query_time seconds.
See Section 5.2.5, “The Slow Query Log”.
Opens
The number of tables the server has opened.
Flush tables
The number of flush-*,
refresh, and reload
commands the server has executed.
Open tables
The number of tables that currently are open.
Memory in use
The amount of memory allocated directly by
mysqld. This value is displayed only when
MySQL has been compiled with
--with-debug=full.
Maximum memory used
The maximum amount of memory allocated directly by
mysqld. This value is displayed only when
MySQL has been compiled with
--with-debug=full.
If you execute mysqladmin shutdown when
connecting to a local server using a Unix socket file,
mysqladmin waits until the server's process
ID file has been removed, to ensure that the server has stopped
properly.
mysqladmin supports the following options,
which can be specified on the command line or in the
[mysqladmin] and [client]
option file groups. mysqladmin also supports
the options for processing option files described at
Section 4.2.3.3.1, “Command-Line Options that Affect Option-File Handling”.
Table 4.3. mysqladmin Options
--help,
-?
Display a help message and exit.
--character-sets-dir=path
The directory where character sets are installed. See
Section 9.2, “The Character Set Used for Data and Sorting”.
--compress,
-C
Compress all information sent between the client and the
server if both support compression.
--count=N,
-c N
The number of iterations to make for repeated command
execution if the --sleep
option is given.
--debug[=debug_options],
-#
[debug_options]
Write a debugging log. A typical
debug_options string is
'd:t:o,file_name'.
The default is
'd:t:o,/tmp/mysqladmin.trace'.
--debug-check
Print some debugging information when the program exits.
This option was added in MySQL 5.1.21.
--debug-info
Print debugging information and memory and CPU usage
statistics when the program exits. This option was added in
MySQL 5.1.14.
--default-character-set=charset_name
Use charset_name as the default
character set. See Section 9.2, “The Character Set Used for Data and Sorting”.
--force,
-f
Do not ask for confirmation for the drop
db_name command. With
multiple commands, continue even if an error occurs.
--host=host_name,
-h host_name
Connect to the MySQL server on the given host.
--no-beep,
-b
Suppress the warning beep that is emitted by default for
errors such as a failure to connect to the server. This
option was added in MySQL 5.1.17.
--password[=password],
-p[password]
The password to use when connecting to the server. If you
use the short option form (-p), you
cannot have a space between the option
and the password. If you omit the
password value following the
--password or
-p option on the command line,
mysqladmin prompts for one.
Specifying a password on the command line should be
considered insecure. See
Section 5.5.6.2, “End-User Guidelines for Password Security”. You can use an
option file to avoid giving the password on the command
line.
--pipe,
-W
On Windows, connect to the server via a named pipe. This
option applies only if the server supports named-pipe
connections.
--port=port_num,
-P port_num
The TCP/IP port number to use for the connection.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The connection protocol to use for connecting to the server.
It is useful when the other connection parameters normally
would cause a protocol to be used other than the one you
want. For details on the allowable values, see
Section 4.2.2, “Connecting to the MySQL Server”.
--relative,
-r
Show the difference between the current and previous values
when used with the
--sleep option.
Currently, this option works only with the
extended-status command.
--silent,
-s
Exit silently if a connection to the server cannot be
established.
--sleep=delay,
-i delay
Execute commands repeatedly, sleeping for
delay seconds in between. The
--count option determines
the number of iterations. If
--count is not given,
mysqladmin executes commands indefinitely
until interrupted.
--socket=path,
-S path
For connections to localhost, the Unix
socket file to use, or, on Windows, the name of the named
pipe to use.
--ssl*
Options that begin with
--ssl specify whether to
connect to the server via SSL and indicate where to find SSL
keys and certificates. See Section 5.5.7.3, “SSL Command Options”.
--user=user_name,
-u user_name
The MySQL user name to use when connecting to the server.
--verbose,
-v
Verbose mode. Print more information about what the program
does.
--version,
-V
Display version information and exit.
--vertical,
-E
Print output vertically. This is similar to
--relative, but prints
output vertically.
--wait[=count],
-w[count]
If the connection cannot be established, wait and retry
instead of aborting. If a count
value is given, it indicates the number of times to retry.
The default is one time.
You can also set the following variables by using
--var_name=value
The --set-variable format is deprecated.
syntax:
4.5.3. mysqlcheck — A Table Maintenance Program
The mysqlcheck client performs table
maintenance: It checks, repairs, optimizes, or analyzes tables.
Each table is locked and therefore unavailable to other sessions
while it is being processed, although for check operations, the
table is locked with a READ lock only (see
Section 12.4.5, “LOCK TABLES and
UNLOCK
TABLES Syntax”, for more information about
READ and WRITE locks).
Table maintenance operations can be time-consuming, particularly
for large tables. If you use the
--databases or
--all-databases option to
process all tables in one or more databases, an invocation of
mysqlcheck might take a long time. (This is
also true for mysql_upgrade because that
program invokes mysqlcheck to check all
tables and repair them if necessary.)
mysqlcheck is similar in function to
myisamchk, but works differently. The main
operational difference is that mysqlcheck
must be used when the mysqld server is
running, whereas myisamchk should be used
when it is not. The benefit of using
mysqlcheck is that you do not have to stop
the server to perform table maintenance.
mysqlcheck uses the SQL statements
CHECK TABLE,
REPAIR TABLE,
ANALYZE TABLE, and
OPTIMIZE TABLE in a convenient
way for the user. It determines which statements to use for the
operation you want to perform, and then sends the statements to
the server to be executed. For details about which storage
engines each statement works with, see the descriptions for
those statements in Section 12.5.2, “Table Maintenance Statements”.
The MyISAM storage engine supports all four
maintenance operations, so mysqlcheck can be
used to perform any of them on MyISAM tables.
Other storage engines do not necessarily support all operations.
In such cases, an error message is displayed. For example, if
test.t is a MEMORY table,
an attempt to check it produces this result:
shell> mysqlcheck test t
test.t
note : The storage engine for the table doesn't support check
If mysqlcheck is unable to repair a table,
see Section 2.4.4, “Rebuilding or Repairing Tables or Indexes” for manual table repair
strategies. This will be the case, for example, for
InnoDB tables, which can be checked with
CHECK TABLE, but not repaired
with REPAIR TABLE.
The use of mysqlcheck with partitioned tables
is not supported before MySQL 5.1.27.
Caution
It is best to make a backup of a table before performing a
table repair operation; under some circumstances the operation
might cause data loss. Possible causes include but are not
limited to file system errors.
There are three general ways to invoke
mysqlcheck:
shell> mysqlcheck [options] db_name [tbl_name ...]
shell> mysqlcheck [options] --databases db_name ...
shell> mysqlcheck [options] --all-databases
If you do not name any tables following
db_name or if you use the
--databases or
--all-databases option,
entire databases are checked.
mysqlcheck has a special feature compared to
other client programs. The default behavior of checking tables
(--check) can be changed by
renaming the binary. If you want to have a tool that repairs
tables by default, you should just make a copy of
mysqlcheck named
mysqlrepair, or make a symbolic link to
mysqlcheck named
mysqlrepair. If you invoke
mysqlrepair, it repairs tables.
The following names can be used to change
mysqlcheck default behavior.
mysqlcheck supports the following options,
which can be specified on the command line or in the
[mysqlcheck] and [client]
option file groups. mysqlcheck also supports
the options for processing option files described at
Section 4.2.3.3.1, “Command-Line Options that Affect Option-File Handling”.
Table 4.4. mysqlcheck Options
--help,
-?
Display a help message and exit.
--all-databases,
-A
Check all tables in all databases. This is the same as using
the --databases option
and naming all the databases on the command line.
--all-in-1,
-1
Instead of issuing a statement for each table, execute a
single statement for each database that names all the tables
from that database to be processed.
--analyze,
-a
Analyze the tables.
MySQL Enterprise
For expert advice on optimizing tables, subscribe to the
MySQL Enterprise Monitor. For more information, see
http://www.mysql.com/products/enterprise/advisors.html.
--auto-repair
If a checked table is corrupted, automatically fix it. Any
necessary repairs are done after all tables have been
checked.
--character-sets-dir=path
The directory where character sets are installed. See
Section 9.2, “The Character Set Used for Data and Sorting”.
--check,
-c
Check the tables for errors. This is the default operation.
--check-only-changed,
-C
Check only tables that have changed since the last check or
that have not been closed properly.
--check-upgrade,
-g
Invoke CHECK TABLE with the
FOR UPGRADE option to check tables for
incompatibilities with the current version of the server.
This option automatically enables the
--fix-db-names and
--fix-table-names
options. --check-upgrade
was added in MySQL 5.1.7.
--compress
Compress all information sent between the client and the
server if both support compression.
--databases,
-B
Process all tables in the named databases. Normally,
mysqlcheck treats the first name argument
on the command line as a database name and following names
as table names. With this option, it treats all name
arguments as database names.
--debug[=debug_options],
-#
[debug_options]
Write a debugging log. A typical
debug_options string is
'd:t:o,file_name'.
The default is 'd:t:o'.
--debug-check
Print some debugging information when the program exits.
This option was added in MySQL 5.1.21.
--debug-info
Print debugging information and memory and CPU usage
statistics when the program exits. This option was added in
MySQL 5.1.14.
--default-character-set=charset_name
Use charset_name as the default
character set. See Section 9.2, “The Character Set Used for Data and Sorting”.
--extended,
-e
If you are using this option to check tables, it ensures
that they are 100% consistent but takes a long time.
If you are using this option to repair tables, it runs an
extended repair that may not only take a long time to
execute, but may produce a lot of garbage rows also!
--fast,
-F
Check only tables that have not been closed properly.
--fix-db-names
Convert database names to 5.1 format. Only database names
that contain special characters are affected. This option
was added in MySQL 5.1.7.
--fix-table-names
Convert table names to 5.1 format. Only table names that
contain special characters are affected. This option was
added in MySQL 5.1.7. As of MySQL 5.1.23, this option also
applies to views.
--force,
-f
Continue even if an SQL error occurs.
--host=host_name,
-h host_name
Connect to the MySQL server on the given host.
--medium-check,
-m
Do a check that is faster than an
--extended operation.
This finds only 99.99% of all errors, which should be good
enough in most cases.
--optimize,
-o
Optimize the tables.
--password[=password],
-p[password]
The password to use when connecting to the server. If you
use the short option form (-p), you
cannot have a space between the option
and the password. If you omit the
password value following the
--password or
-p option on the command line,
mysqlcheck prompts for one.
Specifying a password on the command line should be
considered insecure. See
Section 5.5.6.2, “End-User Guidelines for Password Security”. You can use an
option file to avoid giving the password on the command
line.
--pipe,
-W
On Windows, connect to the server via a named pipe. This
option applies only if the server supports named-pipe
connections.
--port=port_num,
-P port_num
The TCP/IP port number to use for the connection.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The connection protocol to use for connecting to the server.
It is useful when the other connection parameters normally
would cause a protocol to be used other than the one you
want. For details on the allowable values, see
Section 4.2.2, “Connecting to the MySQL Server”.
--quick,
-q
If you are using this option to check tables, it prevents
the check from scanning the rows to check for incorrect
links. This is the fastest check method.
If you are using this option to repair tables, it tries to
repair only the index tree. This is the fastest repair
method.
--repair,
-r
Perform a repair that can fix almost anything except unique
keys that are not unique.
--silent,
-s
Silent mode. Print only error messages.
--socket=path,
-S path
For connections to localhost, the Unix
socket file to use, or, on Windows, the name of the named
pipe to use.
--ssl*
Options that begin with
--ssl specify whether to
connect to the server via SSL and indicate where to find SSL
keys and certificates. See Section 5.5.7.3, “SSL Command Options”.
--tables
Override the --databases
or -B option. All name arguments following
the option are regarded as table names.
--use-frm
For repair operations on MyISAM tables,
get the table structure from the .frm
file so that the table can be repaired even if the
.MYI header is corrupted.
--user=user_name,
-u user_name
The MySQL user name to use when connecting to the server.
--verbose,
-v
Verbose mode. Print information about the various stages of
program operation.
--version,
-V
Display version information and exit.
--write-binlog
This option is enabled by default, so that
ANALYZE TABLE,
OPTIMIZE TABLE, and
REPAIR TABLE statements
generated by mysqlcheck are written to
the binary log. Use
--skip-write-binlog
to cause NO_WRITE_TO_BINLOG to be added
to the statements so that they are not logged. Use the
--skip-write-binlog
when these statements should not be sent to replication
slaves or run when using the binary logs for recovery from
backup. This option was added in MySQL 5.1.18.
4.5.4. mysqldump — A Database Backup Program
The mysqldump client is a backup program
originally written by Igor Romanenko. It can be used to dump a
database or a collection of databases for backup or transfer to
another SQL server (not necessarily a MySQL server). The dump
typically contains SQL statements to create the table, populate
it, or both. However, mysqldump can also be
used to generate files in CSV, other delimited text, or XML
format.
If you are doing a backup on the server and your tables all are
MyISAM tables, consider using the
mysqlhotcopy instead because it can
accomplish faster backups and faster restores. See
Section 4.6.9, “mysqlhotcopy — A Database Backup Program”.
There are three general ways to invoke
mysqldump:
shell> mysqldump [options] db_name [tbl_name ...]
shell> mysqldump [options] --databases db_name ...
shell> mysqldump [options] --all-databases
If you do not name any tables following
db_name or if you use the
--databases or
--all-databases option, entire
databases are dumped.
mysqldump does not dump the
INFORMATION_SCHEMA database by default. As of
MySQL 5.1.38, mysqldump dumps
INFORMATION_SCHEMA if you name it explicitly
on the command line, although currently you must also use the
--skip-lock-tables
option. Before 5.1.38, mysqldump silently
ignores INFORMATION_SCHEMA even if you name
it explicitly on the command line.
To see a list of the options your version of
mysqldump supports, execute
mysqldump --help.
Some mysqldump options are shorthand for
groups of other options:
Use of --opt is the same
as specifying
--add-drop-table,
--add-locks,
--create-options,
--disable-keys,
--extended-insert,
--lock-tables,
--quick, and
--set-charset. All of the
options that --opt stands
for also are on by default because
--opt is on by default.
Use of --compact is the
same as specifying
--skip-add-drop-table,
--skip-add-locks,
--skip-comments,
--skip-disable-keys,
and
--skip-set-charset
options.
To reverse the effect of a group option, uses its
--skip-xxx form
(--skip-opt or
--skip-compact).
It is also possible to select only part of the effect of a group
option by following it with options that enable or disable
specific features. Here are some examples:
When you selectively enable or disable the effect of a group
option, order is important because options are processed first
to last. For example,
--disable-keys
--lock-tables
--skip-opt would not have the
intended effect; it is the same as
--skip-opt by itself.
mysqldump can retrieve and dump table
contents row by row, or it can retrieve the entire content from
a table and buffer it in memory before dumping it. Buffering in
memory can be a problem if you are dumping large tables. To dump
tables row by row, use the
--quick option (or
--opt, which enables
--quick). The
--opt option (and hence
--quick) is enabled by
default, so to enable memory buffering, use
--skip-quick.
If you are using a recent version of
mysqldump to generate a dump to be reloaded
into a very old MySQL server, you should not use the
--opt or
--extended-insert option. Use
--skip-opt instead.
Note
mysqldump from MySQL 5.1.21 cannot be used
to create dumps from MySQL server 5.1.20 and older. This issue
is fixed in MySQL 5.1.22. (Bug#30123)
mysqldump supports the following options,
which can be specified on the command line or in the
[mysqldump] and [client]
option file groups. mysqldump also supports
the options for processing option files described at
Section 4.2.3.3.1, “Command-Line Options that Affect Option-File Handling”.
Table 4.5. mysqldump Options | |