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Chapter 4. MySQL Programs

Table of Contents

4.1. Overview of MySQL Programs
4.2. Using MySQL Programs
4.2.1. Invoking MySQL Programs
4.2.2. Connecting to the MySQL Server
4.2.3. Specifying Program Options
4.2.4. Setting Environment Variables
4.3. MySQL Server and Server-Startup Programs
4.3.1. mysqld — The MySQL Server
4.3.2. mysqld_safe — MySQL Server Startup Script
4.3.3. mysql.server — MySQL Server Startup Script
4.3.4. mysqld_multi — Manage Multiple MySQL Servers
4.4. MySQL Installation-Related Programs
4.4.1. comp_err — Compile MySQL Error Message File
4.4.2. make_win_bin_dist — Package MySQL Distribution as ZIP Archive
4.4.3. mysqlbug — Generate Bug Report
4.4.4. mysql_fix_privilege_tables — Upgrade MySQL System Tables
4.4.5. mysql_install_db — Initialize MySQL Data Directory
4.4.6. mysql_secure_installation — Improve MySQL Installation Security
4.4.7. mysql_tzinfo_to_sql — Load the Time Zone Tables
4.4.8. mysql_upgrade — Check Tables for MySQL Upgrade
4.5. MySQL Client Programs
4.5.1. mysql — The MySQL Command-Line Tool
4.5.2. mysqladmin — Client for Administering a MySQL Server
4.5.3. mysqlcheck — A Table Maintenance Program
4.5.4. mysqldump — A Database Backup Program
4.5.5. mysqlimport — A Data Import Program
4.5.6. mysqlshow — Display Database, Table, and Column Information
4.5.7. mysqlslap — Load Emulation Client
4.6. MySQL Administrative and Utility Programs
4.6.1. innochecksum — Offline InnoDB File Checksum Utility
4.6.2. myisam_ftdump — Display Full-Text Index information
4.6.3. myisamchk — MyISAM Table-Maintenance Utility
4.6.4. myisamlog — Display MyISAM Log File Contents
4.6.5. myisampack — Generate Compressed, Read-Only MyISAM Tables
4.6.6. mysqlaccess — Client for Checking Access Privileges
4.6.7. mysqlbinlog — Utility for Processing Binary Log Files
4.6.8. mysqldumpslow — Summarize Slow Query Log Files
4.6.9. mysqlhotcopy — A Database Backup Program
4.6.10. mysqlmanager — The MySQL Instance Manager
4.6.11. mysql_convert_table_format — Convert Tables to Use a Given Storage Engine
4.6.12. mysql_find_rows — Extract SQL Statements from Files
4.6.13. mysql_fix_extensions — Normalize Table File Name Extensions
4.6.14. mysql_setpermission — Interactively Set Permissions in Grant Tables
4.6.15. mysql_waitpid — Kill Process and Wait for Its Termination
4.6.16. mysql_zap — Kill Processes That Match a Pattern
4.7. MySQL Program Development Utilities
4.7.1. msql2mysql — Convert mSQL Programs for Use with MySQL
4.7.2. mysql_config — Get Compile Options for Compiling Clients
4.7.3. my_print_defaults — Display Options from Option Files
4.7.4. resolve_stack_dump — Resolve Numeric Stack Trace Dump to Symbols
4.8. Miscellaneous Programs
4.8.1. perror — Explain Error Codes
4.8.2. replace — A String-Replacement Utility
4.8.3. resolveip — Resolve Host name to IP Address or Vice Versa

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:

MySQL client programs:

MySQL administrative and utility programs:

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.

MYSQL_UNIX_PORTThe default Unix socket file; used for connections to localhost
MYSQL_TCP_PORTThe default port number; used for TCP/IP connections
MYSQL_PWDThe default password
MYSQL_DEBUGDebug trace options when debugging
TMPDIRThe directory where temporary tables and files are created

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 Programs

4.2.1. 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.

    --protocol ValueConnection ProtocolAllowable Operating Systems
    TCPTCP/IP connection to local or remote serverAll
    SOCKETUnix socket file connection to local serverUnix only
    PIPENamed-pipe connection to local or remote serverWindows only
    MEMORYShared-memory connection to local serverWindows only
  • --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.

Note

Option files used with MySQL Cluster programs are covered in Section 17.3, “MySQL Cluster Configuration”.

On Windows, MySQL programs read startup options from the following files.

File NamePurpose
WINDIR\my.ini, WINDIR\my.cnfGlobal options
C:\my.ini, C:\my.cnfGlobal options
INSTALLDIR\my.ini, INSTALLDIR\my.cnfGlobal options
defaults-extra-fileThe file specified with --defaults-extra-file=path, if any

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.

File NamePurpose
/etc/my.cnfGlobal options
/etc/mysql/my.cnfGlobal options (as of MySQL 5.1.15)
SYSCONFDIR/my.cnfGlobal options
$MYSQL_HOME/my.cnfServer-specific options
defaults-extra-fileThe file specified with --defaults-extra-file=path, if any
~/.my.cnfUser-specific options

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

FormatConfig FileDescriptionIntroductionDeprecatedRemoved
--autocloseautocloseOn NetWare, mysqld_safe provides a screen presence   
--basedir=pathbasedirThe path to the MySQL installation directory   
--core-file-size=sizecore-file-sizeThe size of the core file that mysqld should be able to create   
--datadir=pathdatadirThe path to the data directory   
--defaults-extra-file=pathdefaults-extra-fileThe name of an option file to be read in addition to the usual option files   
--defaults-file=file_namedefaults-fileThe name of an option file to be read instead of the usual option files   
--help Display a help message and exit   
--ledir=pathledirUse this option to indicate the path name to the directory where the server is located   
--log-error=file_namelog-errorWrite the error log to the given file   
--mysqld=prog_namemysqldThe name of the server program (in the ledir directory) that you want to start   
--mysqld-version=suffixmysqld-versionThis option is similar to the --mysqld option, but you specify only the suffix for the server program name   
--nice=priorityniceUse the nice program to set the server's scheduling priority to the given value   
--no-defaultsno-defaultsDo not read any option files   
--open-files-limit=countopen-files-limitThe number of files that mysqld should be able to open   
--pid-filepid-fileThe path name of the process ID file   
--port=numberportThe port number that the server should use when listening for TCP/IP connections   
--skip-kill-mysqldskip-kill-mysqldDo not try to kill stray mysqld processes   
--skip-syslogskip-syslogDo not write error messages to syslog; use error log file5.1.20  
--socket=pathsocketThe Unix socket file that the server should use when listening for local connections   
--syslogsyslogWrite error messages to syslog5.1.20  
--timezone=timezonetimezoneSet the TZ time zone environment variable to the given option value   
--user={user_name|user_id}userRun the mysqld server as the user having the name user_name or the numeric user ID user_id   
  • --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:

  1. Runs a number of system and option checks.

  2. Runs a check on MyISAM tables.

  3. Provides a screen presence for the MySQL server.

  4. Starts mysqld, monitors it, and restarts it if it terminates in error.

  5. Sends error messages from mysqld to the host_name.err file in the data directory.

  6. Sends mysqld_safe screen output to the host_name.safe file in the data directory.

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

Note

In MySQL 5.1.7, mysql_fix_privilege_tables was superseded by mysql_upgrade, which should be used instead. See Section 4.4.8, “mysql_upgrade — Check Tables for MySQL Upgrade”.

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:

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

4.5.1.1. mysql Options

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”.

Table 4.2. mysql Options

FormatConfig FileDescriptionIntroductionDeprecatedRemoved
--auto-rehashauto-rehashEnable automatic rehashing   
--batchbatchDon't use history file   
--character-sets-dir=namecharacter-sets-dirSet the default character set   
--column-namescolumn-namesWrite column names in results   
--column-type-infocolumn-type-infoDisplay result set metadata5.1.14  
--commentscommentsWhether to retain or strip comments in statements sent to the server5.1.23  
--compresscompressCompress all information sent between the client and the server   
--connect_timeout=valueconnect_timeoutThe number of seconds before connection timeout   
--database=dbnamedatabaseThe database to use   
--debug[=debug_options]debugWrite a debugging log   
--debug-checkdebug-checkPrint debugging information when the program exits5.1.21  
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits   
--default-character-set=charset_namedefault-character-setUse charset_name as the default character set   
--delimiter=strdelimiterSet the statement delimiter   
--execute=statementexecuteExecute the statement and quit   
--forceforceContinue even if an SQL error occurs   
--help Display help message and exit   
--host=host_namehostConnect to the MySQL server on the given host   
--htmlhtmlProduce HTML output   
--ignore-spacesignore-spacesIgnore spaces after function names   
--line-numbersline-numbersWrite line numbers for errors   
--local-infile[={0|1}]local-infileEnable or disable for LOCAL capability for LOAD DATA INFILE   
--max_allowed_packet=valuemax_allowed_packetThe maximum packet length to send to or receive from the server   
--max_join_size=valuemax_join_sizeThe automatic limit for rows in a join when using --safe-updates   
--named-commandsnamed-commandsEnable named mysql commands   
--net_buffer_length=valuenet_buffer_lengthThe buffer size for TCP/IP and socket communication   
--no-auto-rehash Disable automatic rehashing   
--no-beepno-beepDo not beep when errors occur   
--no-named-commandsno-named-commandsDisable named mysql commands   
--no-pagerno-pagerDeprecated form of --skip-pager   
--no-teeno-teeDo not copy output to a file   
--one-databaseone-databaseIgnore statements except those for the default database named on the command line   
--pager[=command]pagerUse the given command for paging query output   
--password[=password]passwordThe password to use when connecting to the server   
--port=port_numportThe TCP/IP port number to use for the connection   
--prompt=format_strpromptSet the prompt to the specified format   
--protocol=typeprotocolThe connection protocol to use   
--quickquickDo not cache each query result   
--rawrawWrite column values without escape conversion   
--reconnectreconnectIf the connection to the server is lost, automatically try to reconnect   
--safe-updatessafe-updatesAllow only UPDATE and DELETE statements that specify key values   
--secure-authsecure-authDo not send passwords to the server in old (pre-4.1.1) format   
--select_limit=valueselect_limitThe automatic limit for SELECT statements when using --safe-updates   
--show-warningsshow-warningsShow warnings after each statement if there are any   
--sigint-ignoresigint-ignoreIgnore SIGINT signals (typically the result of typing Control-C)   
--silentsilentSilent mode   
--skip-auto-rehashskip-auto-rehashDisable automatic rehashing   
--skip-column-namesskip-column-namesDo not write column names in results   
--skip-line-numbersskip-line-numbersSkip line numbers for errors   
--skip-named-commandsskip-named-commandsDisable named mysql commands   
--skip-pagerskip-pagerDisable paging   
--skip-reconnectskip-reconnectDisable reconnecting   
--socket=pathsocketFor connections to localhost   
--ssl-ca=file_namessl-caThe path to a file that contains a list of trusted SSL CAs   
--ssl-capath=directory_namessl-capathThe path to a directory that contains trusted SSL CA certificates in PEM format   
--ssl-cert=file_namessl-certThe name of the SSL certificate file to use for establishing a secure connection   
--ssl-cipher=cipher_listssl-cipherA list of allowable ciphers to use for SSL encryption   
--ssl-key=file_namessl-keyThe name of the SSL key file to use for establishing a secure connection   
--ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server   
--tabletableDisplay output in tabular format   
--tee=file_nameteeAppend a copy of output to the given file   
--unbufferedunbufferedFlush the buffer after each query   
--user=user_nameuserThe MySQL user name to use when connecting to the server   
--verbose Verbose mode   
--version Display version information and exit   
--verticalverticalPrint query output rows vertically (one line per column value)   
--waitwaitIf the connection cannot be established, wait and retry instead of aborting   
--xmlxmlProduce XML output   
  • --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.

4.5.1.2. mysql Commands

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.

OptionDescription
\cA counter that increments for each statement you issue
\DThe full current date
\dThe default database
\hThe server host
\lThe current delimiter (new in 5.1.12)
\mMinutes of the current time
\nA newline character
\OThe current month in three-letter format (Jan, Feb, …)
\oThe current month in numeric format
\Pam/pm
\pThe current TCP/IP port or socket file
\RThe current time, in 24-hour military time (0–23)
\rThe current time, standard 12-hour time (1–12)
\SSemicolon
\sSeconds of the current time
\tA tab character
\U

Your full user_name@host_name account name

\uYour user name
\vThe server version
\wThe current day of the week in three-letter format (Mon, Tue, …)
\YThe current year, four digits
\yThe current year, two digits
\_A space
A space (a space follows the backslash)
\'Single quote
\"Double quote
\\A literal “\” backslash character
\x

x, for any “x” not listed above

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 Help

mysql> 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”.

4.5.1.5. mysql Tips

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)
4.5.1.5.2. Using the --safe-updates Option

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

FormatConfig FileDescriptionIntroductionDeprecatedRemoved
--compresscompressCompress all information sent between the client and the server   
--connect_timeout=secondsconnect_timeoutThe number of seconds before connection timeout   
--count=#countThe number of iterations to make for repeated command execution   
--debug[=debug_options]debugWrite a debugging log   
--debug-checkdebug-checkPrint debugging information when the program exits5.1.21  
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits5.1.14  
--default-character-set=charset_namedefault-character-setUse charset_name as the default character set   
--forceforceContinue even if an SQL error occurs   
--help Display help message and exit   
--host=host_namehostConnect to the MySQL server on the given host   
--no-beepno-beepDo not beep when errors occur5.1.17  
--password[=password]passwordThe password to use when connecting to the server   
--pipe On Windows, connect to server via a named pipe   
--port=port_numportThe TCP/IP port number to use for the connection   
--protocol=typeprotocolThe connection protocol to use   
--relativerelativeShow the difference between the current and previous values when used with the --sleep option   
--shutdown_timeout=secondsshutdown_timeoutThe maximum number of seconds to wait for server shutdown   
--silentsilentSilent mode   
--sleep=delaysleepExecute commands repeatedly, sleeping for delay seconds in between   
--socket=pathsocketFor connections to localhost   
--ssl-ca=file_namessl-caThe path to a file that contains a list of trusted SSL CAs   
--ssl-capath=directory_namessl-capathThe path to a directory that contains trusted SSL CA certificates in PEM format   
--ssl-cert=file_namessl-certThe name of the SSL certificate file to use for establishing a secure connection   
--ssl-cipher=cipher_listssl-cipherA list of allowable ciphers to use for SSL encryption   
--ssl-key=file_namessl-keyThe name of the SSL key file to use for establishing a secure connection   
--ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server   
--user=user_name,userThe MySQL user name to use when connecting to the server   
--verbose Verbose mode   
--version Display version information and exit   
--verticalverticalPrint query output rows vertically (one line per column value)   
--waitwaitIf the connection cannot be established, wait and retry instead of aborting   
  • --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:

  • connect_timeout

    The maximum number of seconds before connection timeout. The default value is 43200 (12 hours).

  • shutdown_timeout

    The maximum number of seconds to wait for server shutdown. The default value is 3600 (1 hour).

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.

mysqlrepairThe default option is --repair
mysqlanalyzeThe default option is --analyze
mysqloptimizeThe default option is --optimize

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

FormatConfig FileDescriptionIntroductionDeprecatedRemoved
--all-databasesall-databasesCheck all tables in all databases   
--all-in-1all-in-1Execute a single statement for each database that names all the tables from that database   
--analyzeanalyzeAnalyze the tables   
--auto-repairauto-repairIf a checked table is corrupted, automatically fix it   
--character-sets-dir=pathcharacter-sets-dirThe directory where character sets are installed   
--checkcheckCheck the tables for errors   
--check-only-changedcheck-only-changedCheck only tables that have changed since the last check   
--check-upgradecheck-upgradeInvoke CHECK TABLE with the FOR UPGRADE option5.1.7  
--compresscompressCompress all information sent between the client and the server   
--databasesdatabasesProcess all tables in the named databases   
--debug[=debug_options]debugWrite a debugging log   
--debug-checkdebug-checkPrint debugging information when the program exits5.1.21  
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits5.1.14  
--default-character-set=charset_namedefault-character-setUse charset_name as the default character set   
--extendedextendedCheck and repair tables   
--fastfastCheck only tables that have not been closed properly   
--fix-db-namesfix-db-namesConvert database names to 5.1 format5.1.7  
--fix-table-namesfix-table-namesConvert table names to 5.1 format5.1.7  
--forceforceContinue even if an SQL error occurs   
--help Display help message and exit   
--host=host_namehostConnect to the MySQL server on the given host   
--medium-checkmedium-checkDo a check that is faster than an --extended operation   
--optimizeoptimizeOptimize the tables   
--password[=password]passwordThe password to use when connecting to the server   
--pipe On Windows, connect to server via a named pipe   
--port=port_numportThe TCP/IP port number to use for the connection   
--protocol=typeprotocolThe connection protocol to use   
--quickquickThe fastest method of checking   
--repairrepairPerform a repair that can fix almost anything except unique keys that are not unique   
--silentsilentSilent mode   
--socket=pathsocketFor connections to localhost   
--ssl-ca=file_namessl-caThe path to a file that contains a list of trusted SSL CAs   
--ssl-capath=directory_namessl-capathThe path to a directory that contains trusted SSL CA certificates in PEM format   
--ssl-cert=file_namessl-certThe name of the SSL certificate file to use for establishing a secure connection   
--ssl-cipher=cipher_listssl-cipherA list of allowable ciphers to use for SSL encryption   
--ssl-key=file_namessl-keyThe name of the SSL key file to use for establishing a secure connection   
--ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server   
--tablestablesOverrides the --databases or -B option   
--use-frmuse-frmFor repair operations on MyISAM tables   
--user=user_name,userThe MySQL user name to use when connecting to the server   
--verbose Verbose mode   
--version Display version information and exit   
--write-binlogwrite-binlogLog ANALYZE, OPTIMIZE, REPAIR statements to binary log. --skip-write-binlog adds NO_WRITE_TO_BINLOG to these statements.5.1.18  
  • --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:

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

FormatConfig FileDescriptionIntroductionDeprecatedRemoved
--add-drop-databaseadd-drop-databaseAdd a DROP DATABASE statement before each CREATE DATABASE statement   
--add-drop-tableadd-drop-tableAdd a DROP TABLE statement before each CREATE TABLE statement   
--add-locksadd-locksSurround each table dump with LOCK TABLES and UNLOCK TABLES statements   
--all-databasesall-databasesDump all tables in all databases   
--all-tablespacesall-tablespacesAdds to a table dump all SQL statements needed to create any tablespaces used by an NDB Cluster table5.1.6  
--allow-keywordsallow-keywordsAllow creation of column names that are keywords   
--commentscommentsAdd comments to the dump file   
--compactcompactProduce more compact output   
--compatible=name[,name,...]compatibleProduce output that is more compatible with other database systems or with older MySQL servers   
--complete-insertcomplete-insertUse complete INSERT statements that include column names   
--create-optionscreate-optionsInclude all MySQL-specific table options in CREATE TABLE statements   
--databasesdatabasesDump several databases   
--debug[=debug_options]debugWrite a debugging log   
--debug-checkdebug-checkPrint debugging information when the program exits5.1.21  
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits5.1.14  
--default-character-set=charset_namedefault-character-setUse charset_name as the default character set   
--delayed-insertdelayed-insertWrite INSERT DELAYED statements rather than INSERT statements   
--delete-master-logsdelete-master-logsOn a master replication server, delete the binary logs after performing the dump operation   
--disable-keysdisable-keysFor each table, surround the INSERT statements with statements to disable and enable keys   
--dump-datedump-dateInclude dump date as "Dump completed on" comment if --comments is given5.1.23  
--eventseventsDump events from the dumped databases5.1.8  
--extended-insertextended-insertUse multiple-row INSERT syntax that include several VALUES lists   
--fields-enclosed-by=stringfields-enclosed-byThis option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE   
--fields-escaped-byfields-escaped-byThis option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE   
--fields-optionally-enclosed-by=stringfields-optionally-enclosed-byThis option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE   
--fields-terminated-by=stringfields-terminated-byThis option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE   
--first-slavefirst-slaveDeprecated; use --lock-all-tables instead   
--flush-logsflush-logsFlush the MySQL server log files before starting the dump   
--flush-privilegesflush-privilegesEmit a FLUSH PRIVILEGES statement after dumping the mysql database   
--help Display help message and exit   
--hex-blobhex-blobDump binary columns using hexadecimal notation (for example, 'abc' becomes 0x616263)   
--hosthostHost to connect to (IP address or hostname)   
--ignore-table=db_name.tbl_nameignore-tableDo not dump the given table   
--insert-ignoreinsert-ignoreWrite INSERT IGNORE statements rather than INSERT statements   
--lines-terminated-by=stringlines-terminated-byThis option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE   
--lock-all-tableslock-all-tablesLock all tables across all databases   
--lock-tableslock-tablesLock all tables before dumping them   
--log-error=file_namelog-errorAppend warnings and errors to the named file5.1.18  
--master-data[=value]master-dataWrite the binary log file name and position to the output   
--max_allowed_packet=valuemax_allowed_packetThe maximum packet length to send to or receive from the server   
--net_buffer_length=valuenet_buffer_lengthThe buffer size for TCP/IP and socket communication   
--no-autocommitno-autocommitEnclose the INSERT statements for each dumped table within SET autocommit = 0 and COMMIT statements   
--no-create-dbno-create-dbThis option suppresses the CREATE DATABASE statements   
--no-create-infono-create-infoDo not write CREATE TABLE statements that re-create each dumped table   
--no-datano-dataDo not dump table contents   
--no-set-namesno-set-namesSame as --skip-set-charset   
--optoptShorthand for --add-drop-table --add-locks --create-options --disable-keys --extended-insert --lock-tables --quick --set-charset.   
--order-by-primaryorder-by-primaryDump each table's rows sorted by its primary key, or by its first unique index   
--password[=password]passwordThe password to use when connecting to the server   
--pipe On Windows, connect to server via a named pipe   
--port=port_numportThe TCP/IP port number to use for the connection   
--quickquickRetrieve rows for a table from the server a row at a time   
--quote-namesquote-namesQuote identifiers within backtick characters   
--replacereplaceWrite REPLACE statements rather than INSERT statements5.1.3  
--result-file=fileresult-fileDirect output to a given file   
--routinesroutinesDump stored routines (procedures and functions) from the dumped databases5.1.2  
--set-charsetset-charsetAdd SET NAMES def