Глава 4. MySQL Programs

Содержание

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. mysqlbug — Generate Bug Report
4.4.3. mysql_install_db — Initialize MySQL Data Directory
4.4.4. mysql_plugin — Configure MySQL Server Plugins
4.4.5. mysql_secure_installation — Improve MySQL Installation Security
4.4.6. mysql_tzinfo_to_sql — Load the Time Zone Tables
4.4.7. 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. mysql_convert_table_format — Convert Tables to Use a Given Storage Engine
4.6.11. mysql_find_rows — Extract SQL Statements from Files
4.6.12. mysql_fix_extensions — Normalize Table File Name Extensions
4.6.13. mysql_setpermission — Interactively Set Permissions in Grant Tables
4.6.14. mysql_waitpid — Kill Process and Wait for Its Termination
4.6.15. 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 Oracle Corporation. 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. Глава 16, MySQL Cluster NDB 7.2, 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 Глава 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:

Several programs perform setup operations during MySQL installation or upgrading:

MySQL client programs that connect to the MySQL server:

MySQL administrative and utility programs:

MySQL program-development utilities:

Miscellaneous utilities:

Oracle Corporation 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.

Environment VariableMeaning
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 2.12, “Environment Variables”.

Use of MYSQL_PWD is insecure. See Section 5.3.2.2, “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 enable 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 5.3.2.2, “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 using 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 using 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 using 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 permissible --protocol option values and indicates the platforms on which each value may be used. The values are not case sensitive.

    --protocol ValueConnection ProtocolPermissible 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 using 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 using 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 using SSL, if the server is configured with SSL support. For details, see Section 5.5.8.3, “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 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 5.6.3, “Running Multiple MySQL Instances 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.

Options are processed in order, so 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

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.

You can take advantage of the way that MySQL programs process options by specifying default option values for a program in an option file. That enables you to avoid typing them each time you run the program while enabling you to override the defaults if necessary by using command-line options.

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.

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.)

  • 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
    

Option values that contain spaces must be quoted when given on the command line. For example, the --execute (or -e) option can be used with mysql to pass SQL statements to the server. When this option is used, mysql executes the statements in the option value 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:

mysql> mysql -u root -p --execute="SELECT User, Host FROM mysql.user"
Enter password: ******
+------+-----------+
| User | Host      |
+------+-----------+
|      | gigan     |
| root | gigan     |
|      | localhost |
| jon  | localhost |
| root | localhost |
+------+-----------+
shell>

Note that the long form (--execute) is followed by an equal sign (=).

If you wish to use quoted values within a statement, you will either need to escape the inner quotation marks, or use a different type of quotation marks 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 quotation marks, you can use double quotation marks around the statement, and single quotation marks for any quoted values within the statement.

Multiple SQL statements may be passed in the option value 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 |
+---------------------+

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

As of MySQL 5.5.10, the values ON, TRUE, OFF, and FALSE are also recognized for boolean options (not case sensitive).

If an option is prefixed by --loose, a program does not exit with an error if it does not recognize the option, but instead issues only a warning:

shell> mysql --loose-no-such-option
mysql: WARNING: unknown option '--no-such-option'

The --loose prefix can be useful when you run programs from multiple installations of MySQL on the same machine and list options in an option file, An option that may not be recognized by all versions of a program can be given using the --loose prefix (or loose in an option file). Versions of the program that recognize the option process it normally, and versions that do not recognize it issue a warning and ignore it.

mysqld enables a limit to be placed on how large client programs can set dynamic system variables. To do this, use a --maximum prefix with the variable name. For example, --maximum-query_cache_size=4M prevents any client from making the query cache size larger than 4MB.

4.2.3.3. Using Option Files

Most MySQL programs can read startup options from option files (also sometimes called configuration files). Option files provide a convenient way to specify commonly used options so that they need not be entered on the command line each time you run a program. For the MySQL server, MySQL provides a number of preconfigured option files.

To determine whether a program reads option files, invoke it with the --help option. (For mysqld, use --verbose and --help.) If the program reads option files, the help message indicates which files it looks for and which option groups it recognizes.

On Windows, MySQL programs read startup options from the following files, in the specified order (top items are used first).

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 5.5 Server where PROGRAMDIR represents the programs directory (usually Program Files on English-language versions of Windows), when MySQL 5.5 has been installed using the installation and configuration wizards. See Section 2.3.5.1, “Starting the MySQL Server Instance Configuration Wizard”.

On Unix, Linux and Mac OS X, MySQL programs read startup options from the following files, in the specified order (top items are used first).

File NamePurpose
/etc/my.cnfGlobal options
/etc/mysql/my.cnfGlobal options
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

~ represents the current user's home directory (the value of $HOME).

SYSCONFDIR represents the directory specified with the SYSCONFDIR option to CMake when MySQL was built. By default, this is the etc directory located under the compiled-in installation directory.

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 5.5, 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.

Замечание

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 (see Section 4.2.3.1, “Using Options on the Command Line”). However, in an option file, you omit the leading two dashes from the option name 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 quotation marks or double quotation marks, which is useful if the value contains a “#” comment character.

Leading and trailing spaces 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, “String Literals”.

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 5.5 in an option file. This can be done several ways. Some examples:

basedir="C:\Program Files\MySQL\MySQL Server 5.5"
basedir="C:\\Program Files\\MySQL\\MySQL Server 5.5"
basedir="C:/Program Files/MySQL/MySQL Server 5.5"
basedir=C:\\Program\sFiles\\MySQL\\MySQL\sServer\s5.5

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 enables 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-5.1], [mysqld-5.5], and so forth. The following group indicates that the --new option should be used only by MySQL servers with 5.5.x version numbers:

[mysqld-5.5]
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.

Замечание

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 [mysqladmin] 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 these exceptions:

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. If the file does not exist or is otherwise inaccessible, the program exits with an error. Before MySQL 5.5.8, file_name must be the full path name to the file. As of MySQL 5.5.8, the name is interpreted relative to the current directory if given as a relative path name.

  • --defaults-file=file_name

    Use only the given option file. If the file does not exist or is otherwise inaccessible, the program exits with an error. Before MySQL 5.5.8, file_name must be the full path name to the file. As of MySQL 5.5.8, the name is interpreted relative to the current directory if given as a relative path name.

  • --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.

Замечание

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 12.7.4, “SET Синтаксис”, and Section 5.1.4, “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;
Замечание

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 is deprecated and was removed in MySQL 5.5.3.

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 equal 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: 5.5.22 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 equal 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 equal 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 equal 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 equal sign:

[mysql]

user=jon

Now the login attempt succeeds:

shell> mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.5.22 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: 5.5.22 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)

In MySQL 5.5, specifying an option requiring a value without a value in an option file causes the server to abort with an error. Suppose that my.cnf contains the following:

[mysqld]
log_error
relay_log
relay_log_index

This causes the server to fail on startup, as shown here:

shell> mysqld_safe &

090514 09:48:39 mysqld_safe Logging to '/home/jon/bin/mysql-5.5/var/tonfisk.err'.
090514 09:48:39 mysqld_safe Starting mysqld daemon with databases from /home/jon/bin/mysql-5.5/var
090514 09:48:39 mysqld_safe mysqld from pid file /home/jon/bin/mysql-5.5/var/tonfisk.pid ended

The --log-error option does not require an argument; however, the --relay-log option requires one, as shown in the error log (which in the absence of a specified value, defaults to datadir/hostname.err):

shell> tail -n 3 ../var/tonfisk.err

090514 09:48:39 mysqld_safe Starting mysqld daemon with databases from /home/jon/bin/mysql-5.5/var
090514  9:48:39 [ERROR] /home/jon/bin/mysql-5.5/libexec/mysqld: option '--relay-log' requires an argument
090514  9:48:39 [ERROR] Aborting

This is a change from previous behavior, where the server would have interpreted the last two lines in the example my.cnf file as --relay-log=relay_log_index and created a relay log file using “relay_log_index” as the basename. (Bug #25192)

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 2.12, “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, 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 Глава 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. mysqld_safe adds some safety features such as restarting the server when an error occurs and logging runtime information to an error log file. A description of error logging is given later in this section.

mysqld_safe tries to start an executable named mysqld. To override the default behavior and specify explicitly the name of the server you want to run, specify a --mysqld or --mysqld-version option to mysqld_safe. You can also use --ledir to indicate the directory where mysqld_safe should look for the server.

Many of the options to mysqld_safe are the same as the options to mysqld. 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 5.5 installations.

mysqld_safe supports the following options. 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

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--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   
--malloc-lib=[lib-name]malloc-libAlternative malloc library to use for mysqld   
--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-file=file_namepid-file=file_nameThe 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 file   
--socket=pathsocketThe Unix socket file that the server should use when listening for local connections   
--syslogsyslogWrite error messages to syslog   
--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.

  • --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”.

  • --malloc-lib=[lib_name]

    The name of the library to use for memory allocation instead of the system malloc() library. Any library can be used by specifying its path name, but there is a shortcut form to enable use of the tcmalloc library that is shipped with binary MySQL distributions for Linux in MySQL 5.5.

    The --malloc-lib option works by modifying the LD_PRELOAD environment value to affect dynamic linking to enable the loader to find the memory-allocation library when mysqld runs:

    • If the option is not given, or is given without a value (--malloc-lib=), LD_PRELOAD is not modified and no attempt is made to use tcmalloc.

    • If the option is given as --malloc-lib=tcmalloc, mysqld_safe looks for a tcmalloc library in /usr/lib and then in the MySQL pkglibdir location (for example, /usr/local/mysql/lib or whatever is appropriate). If tmalloc is found, its path name is added to the beginning of the LD_PRELOAD value for mysqld. If tcmalloc is not found, mysqld_safe aborts with an error.

    • If the option is given as --malloc-lib=/path/to/some/library, that full path is added to the beginning of the LD_PRELOAD value. If the full path points to a nonexistent or unreadable file, mysqld_safe aborts with an error.

    • For cases where mysqld_safe adds a path name to LD_PRELOAD, it adds the path to the beginning of any existing value the variable already has.

    Linux users can use the libtcmalloc_minimal.so included in binary packages by adding these lines to the my.cnf file:

    [mysqld_safe]
    malloc-lib=tcmalloc

    Those lines also suffice for users on any platform who have installed a tcmalloc package in /usr/lib. To use a specific tcmalloc library, specify its full path name. Пример:

    [mysqld_safe]
    malloc-lib=/opt/lib/libtcmalloc_minimal.so
  • --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.

  • --syslog-tag=tag

    For logging to syslog, messages from mysqld_safe and mysqld are written with a tag of mysqld_safe and mysqld, respectively. To specify a suffix for the tag, use --syslog-tag=tag, which modifies the tags to be mysqld_safe-tag and mysqld-tag.

  • --timezone=timezone

    Set the TZ time zone environment variable to the given option value. Consult your operating system documentation for legal time zone specification formats.

  • --user={user_name|user_id}

    Run the mysqld server as the user having the name user_name or the numeric user ID user_id. (“User” in this context refers to a system login account, not a 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.

Beginning with MySQL 5.5.21, mysqld_safe tries to use the sleep and date system utilities to determine how many times it has attempted to start this second, and—if these are present and this is greater than 5 times—is forced to wait 1 full second before starting again. This is intended to prevent excessive CPU usage in the event of repeated failures. (Bug #11761530, Bug #54035)

When you use mysqld_safe to start mysqld, mysqld_safe arranges for error (and notice) messages from itself and from mysqld to go to the same destination.

There are several mysqld_safe options for controlling the destination of these messages:

  • --syslog: Write error messages to syslog on systems that support the logger program.

  • --skip-syslog: Do not write error messages to syslog. Messages are written to the default error log file (host_name.err in the data directory), or to a named file if the --log-error option is given.

  • --log-error=file_name: Write error messages to the named error file.

If none of these options is given, the default is --skip-syslog.

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. Ошибки go to the logging destination and stderr.

Normally, you should not edit the mysqld_safe script. Instead, configure mysqld_safe by using command-line options or options in the [mysqld_safe] section of a my.cnf option file. In rare cases, it might be necessary to edit mysqld_safe to get it to start the server properly. However, if you do this, your modified version of mysqld_safe might be overwritten if you upgrade MySQL in the future, so you should make a copy of your edited version that you can reinstall.

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 2.5.1, “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 2.10.1.2, “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 5.5.

mysql.server supports the following options.

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.

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 2.10.1.2, “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 Instances on One 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

mysqld_multi searches for option files as follows:

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.

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.

mysqld_multi supports the following options.

  • --help

    Display a help message and exit.

  • --config-file=file_name

    This option is deprecated. If given, it is treated the same way as --defaults-extra-file, described earlier. --config-file was removed in MySQL 5.5.3.

  • --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”.) Пример:

    [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 through 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 through 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 Instances on One 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 5.3.6, “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 permit 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 superuser (root). 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, available at http://forge.mysql.com/wiki/MySQL_Internals.

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. mysqlbug — Generate Bug Report

This program is obsolete.

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.

4.4.3. 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> scripts/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. If MySQL was configured with the DISABLE_GRANT_OPTIONS compiler flag, --bootstrap and --skip-grant-tables will be disabled (see Section 2.9.4, “MySQL Source-Configuration Options”). 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.

Замечание

If you have set a custom TMPDIR variable when performing the installation, and the specified directory is not accessible, the execution of mysql_install_db may fail. You should unset TMPDIR, or set TMPDIR to point to the system temporary directory (usually /tmp).

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] groups of an option file. Other options are passed to mysqld. For information about option files, see Section 4.2.3.3, “Using Option Files”. mysql_install_db also supports the options for processing option files described at Section 4.2.3.3.1, “Command-Line Options that Affect Option-File Handling”.

  • --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.

  • --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.

4.4.4. mysql_plugin — Configure MySQL Server Plugins

The mysql_plugin utility enables MySQL administrators to manage which plugins a MySQL server loads. It provides an alternative to manually specifying the --plugin-load option at server startup or using the INSTALL PLUGIN and UNINSTALL PLUGIN statements at runtime. mysql_plugin is available as of MySQL 5.5.16.

Depending on whether mysql_plugin is invoked to enable or disable plugins, it inserts or deletes rows in the mysql.plugin table that serves as a plugin registry. (To perform this operation, mysql_plugin invokes the MySQL server in bootstrap mode. This means that the server must not already be running.) For normal server startups, the server loads and enables plugins listed in mysql.plugin automatically. For additional control over plugin activation, use --plugin_name options named for specific plugins, as described in Section 5.1.7.1, “Installing and Uninstalling Plugins”.

Each invocation of mysql_plugin reads a configuration file to determine how to configure the plugins contained in a single plugin library object file. To invoke mysql_plugin, use this syntax:

mysql_plugin [options] plugin {ENABLE|DISABLE}

plugin is the name of the plugin to configure. ENABLE or DISABLE (not case sensitive) specify whether to enable or disable components of the plugin library named in the configuration file. The order of the plugin and ENABLE or DISABLE arguments does not matter.

For example, to configure components of a plugin library file named myplugins.so on Linux or myplugins.dll on Windows, specify a plugin value of myplugins. Suppose that this plugin library contains three plugins, plugin1, plugin2, and plugin3, all of which should be configured under mysql_plugin control. By convention, configuration files have a suffix of .ini and the same basename as the plugin library, so the default configuration file name for this plugin library is myplugins.ini. The configuration file contents look like this:

myplugins
plugin1
plugin2
plugin3

The first line in the myplugins.ini file is the name of the library object file, without any extension such as .so or .dll. The remaining lines are the names of the components to be enabled or disabled. Each value in the file should be on a separate line. Lines on which the first character is '#' are taken as comments and ignored.

To enable the plugins listed in the configuration file, invoke mysql_plugin this way:

shell> mysql_plugin myplugins ENABLE

To disable the plugins, use DISABLE rather than ENABLE.

An error occurs if mysql_plugin cannot find the configuration file or plugin library file, or if mysql_plugin cannot start the MySQL server.

mysql_plugin supports the following options, which can be specified on the command line or in the [mysqld] group of any option file. For options specified in a [mysqld] group, mysql_plugin recognizes the --basedir, --datadir, and --plugin-dir options and ignores others. For information about option files, see Section 4.2.3.3, “Using Option Files”.

mysql_plugin Options

  • --help, -?

    Display a help message and exit.

  • --basedir=path, -b path

    The server base directory.

  • --datadir=path, -d path

    The server data directory.

  • --my-print-defaults=path, -b path

    The path to the my_print_defaults program.

  • --mysqld=path, -b path

    The path to the mysqld server.

  • --no-defaults, -p

    Do not read values from the configuration file. This option enables an administrator to skip reading defaults from the configuration file.

    With mysql_plugin, this option need not be given first on the command line, unlike most other MySQL programs that support --no-defaults.

  • --plugin-dir=path, -p path

    The server plugin directory.

  • --plugin-ini=file_name, -i file_name

    The mysql_plugin configuration file. Relative path names are interpreted relative to the current directory. If this option is not given, the default is plugin.ini in the plugin directory, where plugin is the plugin argument on the command line.

  • --print-defaults, -P

    Display the default values from the configuration file. This option causes mysql_plugin to print the defaults for --basedir, --datadir, and --plugin-dir if they are found in the configuration file. If no value for a variable is found, nothing is shown.

    With mysql_plugin, this option need not be given first on the command line, unlike most other MySQL programs that support --print-defaults.

  • --verbose, -v

    Verbose mode. Print more information about what the program does. This option can be used multiple times to increase the amount of information.

  • --version, -V

    Display version information and exit.

4.4.5. 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 all users, even anonymous users), and privileges that permit anyone to access databases with names that start with test_.

mysql_secure_installation helps you implement security recommendations similar to those described at Section 2.10.2, “Securing the Initial MySQL Accounts”.

Invoke mysql_secure_installation without arguments:

shell> mysql_secure_installation

The script will prompt you to determine which actions to perform.

mysql_secure_installation is not available on Windows.

4.4.6. 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, 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 9.6, “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.

4.4.7. 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 has been removed in MySQL 5.5.

If mysql_upgrade finds that a table has a possible incompatibility, it performs a table check and, if problems are found, attempts a table repair. If the table cannot be repaired, see Section 2.11.4, “Rebuilding or Repairing Tables or Indexes” for manual table repair strategies.

Замечание

On Windows Server 2008, Vista, and newer, 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 2.11.1, “Upgrading MySQL”, for instructions on determining whether any such incompatibilities apply to your installation and how to handle them.

To use mysql_upgrade, make sure that the server is running, and then invoke it like this:

shell> mysql_upgrade [options]

After running mysql_upgrade, stop the server and restart it so that any changes made to the system tables take effect.

mysql_upgrade executes the following commands to check and repair tables and to upgrade the system tables:

mysqlcheck --all-databases --check-upgrade --auto-repair
mysql < fix_priv_tables
mysqlcheck --all-databases --check-upgrade --fix-db-names --fix-table-names

Notes about the preceding commands:

  • Because mysql_upgrade invokes mysqlcheck with the --all-databases option, it processes all tables in all databases, which might take a long time to complete. Each table is locked and therefore unavailable to other sessions while it is being processed. Check and repair operations can be time-consuming, particularly for large tables.

  • For details about what checks the --check-upgrade option entails, see the description of the FOR UPGRADE option of the CHECK TABLE statement (see Section 12.7.2.2, “CHECK TABLE Синтаксис”).

  • fix_priv_tables represents a script generated internally by mysql_upgrade that contains SQL statements to upgrade the tables in the mysql database.

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 2.5.1, “Installing MySQL from RPM Packages on Linux”.)

mysql_upgrade does not upgrade the contents of the help tables. For upgrade instructions, see Section 5.1.8, “Server-Side Help”.

mysql_upgrade supports the following options, which can be specified on the command line or in the [mysql_upgrade] and [client] groups of an option file. 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”.

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.

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

On Unix, the mysql client writes a record of executed statements to a history file. See Section 4.5.1.3, “mysql History File”.

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] groups of an option file. 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

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--auto-rehashauto-rehashEnable automatic rehashing   
--auto-vertical-outputauto-vertical-outputEnable automatic vertical result set display5.5.3  
--batchbatchDon't use history file   
--character-sets-dir=pathcharacter-sets-dirSet the default character set   
--column-namescolumn-namesWrite column names in results   
--column-type-infocolumn-type-infoDisplay result set metadata   
--commentscommentsWhether to retain or strip comments in statements sent to the server   
--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 exits   
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits   
--default-auth=plugindefault-auth=pluginThe authentication plugin to use5.5.7  
--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  5.5.3
--no-pagerno-pagerDeprecated form of --skip-pager  5.5.3
--no-teeno-teeDo not copy output to a file  5.5.3
--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   
--plugin-dir=pathplugin-dir=pathThe directory where plugins are located5.5.7  
--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=dir_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.

  • --auto-vertical-output

    Cause result sets to be displayed vertically if they are too wide for the current window, and using normal tabular format otherwise. (This applies to statements terminated by ; or \G.) This option was added in MySQL 5.5.3.

  • --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.

  • --bind-address=ip_address

    On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server.

    This option is supported only in the version of the mysql client that is supplied with MySQL Cluster. It is not available in standard MySQL Server 5.5 releases.

  • --character-sets-dir=path

    The directory where character sets are installed. See Section 9.5, “Character Set Configuration”.

  • --column-names

    Write column names in results.

  • --column-type-info, -m

    Display result set metadata.

  • --comments, -c

    Whether to preserve comments in statements sent to the server. The default is --skip-comments (discard comments), enable with --comments (preserve comments).

  • --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.

  • --debug-info, -T

    Print debugging information and memory and CPU usage statistics when the program exits.

  • --default-auth=plugin

    The client-side authentication plugin to use. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.7.

  • --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 9.5, “Character Set Configuration”, 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. With this option, mysql does not use the history file.

  • --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 5.1.6, “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.

  • --named-commands, -G

    Enable named mysql commands. Long-format commands are permitted, 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-named-commands was removed in MySQL 5.5.3.

  • --no-pager

    Deprecated form of --skip-pager. See the --pager option. --no-pager was removed in MySQL 5.5.3.

  • --no-tee

    Deprecated form of --skip-tee. See the --tee option. --no-tee is removed in MySQL 5.5.3.

  • --one-database, -o

    Ignore statements except those that occur while the default database is the one named on the command line. This option is rudimentary and should be used with care. Statement filtering is based only on USE statements.

    Initially, mysql executes statements in the input because specifying a database db_name on the command line is equivalent to inserting USE db_name at the beginning of the input. Then, for each USE statement encountered, mysql accepts or rejects following statements depending on whether the database named is the one on the command line. The content of the statements is immaterial.

    Suppose that mysql is invoked to process this set of statements:

    DELETE FROM db2.t2;
    USE db2;
    DROP TABLE db1.t1;
    CREATE TABLE db1.t1 (i INT);
    USE db1;
    INSERT INTO t1 (i) VALUES(1);
    CREATE TABLE db2.t1 (j INT);

    If the command line is mysql --force --one-database db1, mysql handles the input as follows:

    • The DELETE statement is executed because the default database is db1, even though the statement names a table in a different database.

    • The DROP TABLE and CREATE TABLE statements are not executed because the default database is not db1, even though the statements name a table in db1.

    • The INSERT and CREATE TABLE statements are executed because the default database is db1, even though the CREATE TABLE statement names a table in a different database.

  • --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 5.3.2.2, “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 using a named pipe. This option applies only if the server supports named-pipe connections.

  • --plugin-dir=path

    The directory in which to look for plugins. It may be necessary to specify this option if the --default-auth option is used to specify an authentication plugin but mysql does not find it. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.7.

  • --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 permissible 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

    Permit 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 4.5.1.6, “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.

  • --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 using SSL and indicate where to find SSL keys and certificates. See Section 5.5.8.3, “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.

    <field name="column_name">NULL</field>
    

    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.

    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 and was removed in MySQL 5.5.3.

  • 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.)

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 Справочное Руководство. For more information, see Section 4.5.1.4, “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.

  • 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 string can be specified as an unquoted or quoted argument on the delimiter command line. Quoting can be done with either single quote ('), douple quote ("), or backtick (`) characters. To include a quote within a quoted string, either quote the string with a different 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 delimiter 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.

    mysql interprets instances of the delimiter string as a statement delimiter anywhere it occurs, except within quoted strings. Be careful about defining a delimiter that might occur within other words. For example, if you define the delimiter as X, you will be unable to use the word INDEX in statements. mysql interprets this as INDE followed by the delimiter X.

    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 21.9.13, “C API Support for Multiple Statement Execution”), and for parsing the body of stored procedures and functions, triggers, and events (see Section 18.1, “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 using 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.

OptionОписание
\cA counter that increments for each statement you issue
\DThe full current date
\dThe default database
\hThe server host
\lThe current delimiter
\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 permissible 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 History File

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 5.3.2.2, “End-User Guidelines for Password Security”.

It is possible to suppress logging of statements to the history file by using the --batch or --execute option.

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.

4.5.1.4. 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 5.1.8, “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'
Описание:
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 |
+---------------+-----------+

4.5.1.5. 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.

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”.

4.5.1.6. mysql Tips

This section describes some techniques that can help you use mysql more effectively.

4.5.1.6.1. 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)
4.5.1.6.2. 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 5.1.3, “Server System Variables”.

The SET statement has the following effects:

  • You are not permitted 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
4.5.1.6.3. 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 21.9.12, “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.

    This includes information about the Event Scheduler. See Section 18.4.5, “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.

  • 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 5.3.2.3, “Password Hashing in MySQL”.)

  • 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 quotation marks. On Windows, be sure to use double quotation marks rather than single quotation marks; single quotation marks are not stripped from the password, but rather are interpreted as part of the password. For example:

    shell> mysqladmin password "my new password"
    

    As of MySQL 5.5.3, the new password can be omitted following the password command. In this case, mysqladmin prompts for the password value, which enables you to avoid specifying the password on the command line. Omitting the password value should be done only if password is the final command on the mysqladmin command line. Otherwise, the next argument is taken as the 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 available. 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 12.7.5.30, “SHOW PROCESSLIST Синтаксис”.)

  • 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.

  • 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 safemalloc, which is available only before MySQL 5.5.6.

  • Maximum memory used

    The maximum amount of memory allocated directly by mysqld. This value is displayed only when MySQL has been compiled with safemalloc, which is available only before MySQL 5.5.6.

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] groups of an option file. 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

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--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 exits   
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits   
--default-auth=plugindefault-auth=pluginThe authentication plugin to use5.5.9  
--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 occur   
--password[=password]passwordThe password to use when connecting to the server   
--pipe On Windows, connect to server using a named pipe   
--plugin-dir=pathplugin-dir=pathThe directory where plugins are located5.5.9  
--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=dir_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.

  • --bind-address=ip_address

    On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server.

    This option is supported only in the version of mysqladmin that is supplied with MySQL Cluster. It is not available in standard MySQL Server 5.5 releases.

  • --character-sets-dir=path

    The directory where character sets are installed. See Section 9.5, “Character Set Configuration”.

  • --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.

  • --debug-info

    Print debugging information and memory and CPU usage statistics when the program exits.

  • --default-auth=plugin

    The client-side authentication plugin to use. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.9.

  • --default-character-set=charset_name

    Use charset_name as the default character set. See Section 9.5, “Character Set Configuration”.

  • --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.

  • --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 5.3.2.2, “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 using a named pipe. This option applies only if the server supports named-pipe connections.

  • --plugin-dir=path

    The directory in which to look for plugins. It may be necessary to specify this option if the --default-auth option is used to specify an authentication plugin but mysqladmin does not find it. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.9.

  • --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 permissible 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. 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 using SSL and indicate where to find SSL keys and certificates. See Section 5.5.8.3, “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 and was removed in MySQL 5.5.3. 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 12.3.5, “LOCK TABLES and UNLOCK TABLES Синтаксис”, 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 12.7.2, “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 2.11.4, “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.

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 names shown in the following table can be used to change mysqlcheck default behavior.

CommandMeaning
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] groups of an option file. 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

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--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 option   
--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 exits   
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits   
--default-auth=plugindefault-auth=pluginThe authentication plugin to use5.5.10  
--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 format   
--fix-table-namesfix-table-namesConvert table names to 5.1 format   
--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 using a named pipe   
--plugin-dir=pathplugin-dir=pathThe directory where plugins are located5.5.10  
--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=dir_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.   
  • --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.

  • --auto-repair

    If a checked table is corrupted, automatically fix it. Any necessary repairs are done after all tables have been checked.

  • --bind-address=ip_address

    On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server.

    This option is supported only in the version of mysqlcheck that is supplied with MySQL Cluster. It is not available in standard MySQL Server 5.5 releases.

  • --character-sets-dir=path

    The directory where character sets are installed. See Section 9.5, “Character Set Configuration”.

  • --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.

  • --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.

  • --debug-info

    Print debugging information and memory and CPU usage statistics when the program exits.

  • --default-character-set=charset_name

    Use charset_name as the default character set. See Section 9.5, “Character Set Configuration”.

  • --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!

  • --default-auth=plugin

    The client-side authentication plugin to use. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.10.

  • --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.

  • --fix-table-names

    Convert table names to 5.1 format. Only table names that contain special characters are affected. 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 5.3.2.2, “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 using a named pipe. This option applies only if the server supports named-pipe connections.

  • --plugin-dir=path

    The directory in which to look for plugins. It may be necessary to specify this option if the --default-auth option is used to specify an authentication plugin but mysqlcheck does not find it. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.10.

  • --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 permissible 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 using SSL and indicate where to find SSL keys and certificates. See Section 5.5.8.3, “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.

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. mysqldump dumps INFORMATION_SCHEMA only if you name it explicitly on the command line, although currently you must also use the --skip-lock-tables option. Before MySQL 5.5 mysqldump silently ignores INFORMATION_SCHEMA even if you name it explicitly on the command line.

mysqldump does not dump the performance_schema database.

mysqldump also does not dump the MySQL Cluster ndbinfo information database.

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.

For additional information about mysqldump, see Section 6.4, “Using mysqldump for Backups”.

mysqldump supports the following options, which can be specified on the command line or in the [mysqldump] and [client] groups of an option file. 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

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--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   
--allow-keywordsallow-keywordsAllow creation of column names that are keywords   
--apply-slave-statementsapply-slave-statementsInclude STOP SLAVE prior to CHANGE MASTER statement and START SLAVE at end of output5.5.3  
--bind-address=ip_addressbind-addressUse the specified network interface to connect to the MySQL Server5.5.8  
--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 exits   
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits   
--default-auth=plugindefault-auth=pluginThe authentication plugin to use5.5.9  
--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 given   
--dump-slave[=value]dump-slaveInclude CHANGE MASTER statement that lists binary log coordinates of slave's master5.5.3  
--eventseventsDump events from the dumped databases   
--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  5.5.3
--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   
--include-master-host-portinclude-master-host-portInclude MASTER_HOST/MASTER_PORT options in CHANGE MASTER statement produced with --dump-slave5.5.3  
--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 file   
--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   
--no-tablespacesno-tablespacesDo not write any CREATE LOGFILE GROUP or CREATE TABLESPACE statements in output   
--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 using a named pipe   
--plugin-dir=pathplugin-dir=pathThe directory where plugins are located5.5.9  
--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 statements   
--result-file=fileresult-fileDirect output to a given file   
--routinesroutinesDump stored routines (procedures and functions) from the dumped databases   
--set-charsetset-charsetAdd SET NAMES default_character_set to the output   
--single-transactionsingle-transactionThis option issues a BEGIN SQL statement before dumping data from the server   
--skip-add-drop-tableskip-add-drop-tableDo not add a DROP TABLE statement before each CREATE TABLE statement   
--skip-add-locksskip-add-locksDo not add locks   
--skip-commentsskip-commentsDo not add comments to the dump file   
--skip-compactskip-compactDo not produce more compact output   
--skip-disable-keysskip-disable-keysDo not disable keys   
--skip-extended-insertskip-extended-insertTurn off extended-insert   
--skip-optskip-optTurn off the options set by --opt   
--skip-quickskip-quickDo not retrieve rows for a table from the server a row at a time   
--skip-quote-namesskip-quote-namesDo not quote identifiers   
--skip-set-charsetskip-set-charsetSuppress the SET NAMES statement   
--skip-triggersskip-triggersDo not dump triggers   
--skip-tz-utcskip-tz-utcTurn off tz-utc   
--ssl-ca=file_namessl-caThe path to a file that contains a list of trusted SSL CAs   
--ssl-capath=dir_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   
--tab=pathtabProduce tab-separated data files   
--tablestablesOverride the --databases or -B option   
--triggerstriggersDump triggers for each dumped table   
--tz-utctz-utcAdd SET TIME_ZONE='+00:00' to the dump file   
--user=user_nameuserThe MySQL user name to use when connecting to the server   
--verbose Verbose mode   
--version Display version information and exit   
--where='where_condition'whereDump only rows selected by the given WHERE condition   
--xmlxmlProduce XML output   
  • --help, -?

    Display a help message and exit.

  • --add-drop-database

    Add a DROP DATABASE statement before each CREATE DATABASE statement. This option is typically used in conjunction with the --all-databases or --databases option because no CREATE DATABASE statements are written unless one of those options is specified.

  • --add-drop-table

    Add a DROP TABLE statement before each CREATE TABLE statement.

  • --add-drop-trigger

    Add a DROP TRIGGER statement before each CREATE TRIGGER statement.

    Замечание

    This option is supported only by mysqldump as supplied with MySQL Cluster. It is not available when using MySQL Server 5.5.

  • --add-locks

    Surround each table dump with LOCK TABLES and UNLOCK TABLES statements. This results in faster inserts when the dump file is reloaded. See Section 7.2.2.1, “Speed of INSERT Statements”.

  • --all-databases, -A

    Dump all tables in all databases. This is the same as using the --databases option and naming all the databases on the command line.

  • --all-tablespaces, -Y

    Adds to a table dump all SQL statements needed to create any tablespaces used by an NDBCLUSTER table. This information is not otherwise included in the output from mysqldump. This option is currently relevant only to MySQL Cluster tables.

  • --allow-keywords

    Permit creation of column names that are keywords. This works by prefixing each column name with the table name.

  • --apply-slave-statements

    For a slave dump produced with the --dump-slave option, add a STOP SLAVE statement before the CHANGE MASTER TO statement and a START SLAVE statement at the end of the output. This option was added in MySQL 5.5.3.

  • --bind-address=ip_address

    On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server.

    This option is supported only in the version of mysqldump that is supplied with MySQL Cluster. It is not available in standard MySQL Server 5.5 releases.

  • --character-sets-dir=path

    The directory where character sets are installed. See Section 9.5, “Character Set Configuration”.

  • --comments, -i

    Write additional information in the dump file such as program version, server version, and host. This option is enabled by default. To suppress this additional information, use --skip-comments.

  • --compact

    Produce more compact output. This option enables the --skip-add-drop-table, --skip-add-locks, --skip-comments, --skip-disable-keys, and --skip-set-charset options.

  • --compatible=name

    Produce output that is more compatible with other database systems or with older MySQL servers. The value of name can be ansi, mysql323, mysql40, postgresql, oracle, mssql, db2, maxdb, no_key_options, no_table_options, or no_field_options. To use several values, separate them by commas. These values have the same meaning as the corresponding options for setting the server SQL mode. See Section 5.1.6, “Server SQL Modes”.

    This option does not guarantee compatibility with other servers. It only enables those SQL mode values that are currently available for making dump output more compatible. For example, --compatible=oracle does not map data types to Oracle types or use Oracle comment syntax.

    This option requires a server version of 4.1.0 or higher. With older servers, it does nothing.

  • --complete-insert, -c

    Use complete INSERT statements that include column names.

  • --compress, -C

    Compress all information sent between the client and the server if both support compression.

  • --create-options

    Include all MySQL-specific table options in the CREATE TABLE statements.

  • --databases, -B

    Dump several databases. Normally, mysqldump 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. CREATE DATABASE and USE statements are included in the output before each new database.

  • --debug[=debug_options], -# [debug_options]

    Write a debugging log. A typical debug_options string is 'd:t:o,file_name'. The default value is 'd:t:o,/tmp/mysqldump.trace'.

  • --debug-check

    Print some debugging information when the program exits.

  • --debug-info

    Print debugging information and memory and CPU usage statistics when the program exits.

  • --default-auth=plugin

    The client-side authentication plugin to use. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.9.

  • --default-character-set=charset_name

    Use charset_name as the default character set. See Section 9.5, “Character Set Configuration”. If no character set is specified, mysqldump uses utf8, and earlier versions use latin1.

  • --delayed-insert

    Write INSERT DELAYED statements rather than INSERT statements.

  • --delete-master-logs

    On a master replication server, delete the binary logs by sending a PURGE BINARY LOGS statement to the server after performing the dump operation. This option automatically enables --master-data.

  • --disable-keys, -K

    For each table, surround the INSERT statements with /*!40000 ALTER TABLE tbl_name DISABLE KEYS */; and /*!40000 ALTER TABLE tbl_name ENABLE KEYS */; statements. This makes loading the dump file faster because the indexes are created after all rows are inserted. This option is effective only for nonunique indexes of MyISAM tables.

  • --dump-date

    If the --comments option is given, mysqldump produces a comment at the end of the dump of the following form:

    -- Dump completed on DATE
    

    However, the date causes dump files taken at different times to appear to be different, even if the data are otherwise identical. --dump-date and --skip-dump-date control whether the date is added to the comment. The default is --dump-date (include the date in the comment). --skip-dump-date suppresses date printing.

  • --dump-slave[=value]

    This option is similar to --master-data except that it is used to dump a replication slave server to produce a dump file that can be used to set up another server as a slave that has the same master as the dumped server. It causes the dump output to include a CHANGE MASTER TO statement that indicates the binary log coordinates (file name and position) of the dumped slave's master (rather than the coordinates of the dumped server, as is done by the --master-data option). These are the master server coordinates from which the slave should start replicating. This option was added in MySQL 5.5.3.

    The option value is handled the same way as for --master-data and has the same effect as --master-data in terms of enabling or disabling other options and in how locking is handled.

    In conjunction with --dump-slave, the --apply-slave-statements and --include-master-host-port options can also be used.

  • --events, -E

    Include Event Scheduler events for the dumped databases in the output.

  • --extended-insert, -e

    Use multiple-row INSERT syntax that include several VALUES lists. This results in a smaller dump file and speeds up inserts when the file is reloaded.

  • --fields-terminated-by=..., --fields-enclosed-by=..., --fields-optionally-enclosed-by=..., --fields-escaped-by=...

    These options are used with the --tab option and have the same meaning as the corresponding FIELDS clauses for LOAD DATA INFILE. See Section 12.2.6, “LOAD DATA INFILE Синтаксис”.

  • --first-slave

    Deprecated. Use --lock-all-tables instead. --first-slave was removed in MySQL 5.5.3.

  • --flush-logs, -F

    Flush the MySQL server log files before starting the dump. This option requires the RELOAD privilege. If you use this option in combination with the --all-databases option, the logs are flushed for each database dumped. The exception is when using --lock-all-tables or --master-data: In this case, the logs are flushed only once, corresponding to the moment that all tables are locked. If you want your dump and the log flush to happen at exactly the same moment, you should use --flush-logs together with either --lock-all-tables or --master-data.

  • --flush-privileges

    Send a FLUSH PRIVILEGES statement to the server after dumping the mysql database. This option should be used any time the dump contains the mysql database and any other database that depends on the data in the mysql database for proper restoration.

  • --force, -f

    Continue even if an SQL error occurs during a table dump.

    One use for this option is to cause mysqldump to continue executing even when it encounters a view that has become invalid because the definition refers to a table that has been dropped. Without --force, mysqldump exits with an error message. With --force, mysqldump prints the error message, but it also writes an SQL comment containing the view definition to the dump output and continues executing.

  • --host=host_name, -h host_name

    Dump data from the MySQL server on the given host. The default host is localhost.

  • --hex-blob

    Dump binary columns using hexadecimal notation (for example, 'abc' becomes 0x616263). The affected data types are BINARY, VARBINARY, the BLOB types, and BIT.

  • --include-master-host-port

    For the CHANGE MASTER TO statement in a slave dump produced with the --dump-slave option, add MASTER_PORT and MASTER_PORT options for the host name and TCP/IP port number of the slave's master. This option was added in MySQL 5.5.3.

  • --ignore-table=db_name.tbl_name

    Do not dump the given table, which must be specified using both the database and table names. To ignore multiple tables, use this option multiple times. This option also can be used to ignore views.

  • --insert-ignore

    Write INSERT IGNORE statements rather than INSERT statements.

  • --lines-terminated-by=...

    This option is used with the --tab option and has the same meaning as the corresponding LINES clause for LOAD DATA INFILE. See Section 12.2.6, “LOAD DATA INFILE Синтаксис”.

  • --lock-all-tables, -x

    Lock all tables across all databases. This is achieved by acquiring a global read lock for the duration of the whole dump. This option automatically turns off --single-transaction and --lock-tables.

  • --lock-tables, -l

    For each dumped database, lock all tables to be dumped before dumping them. The tables are locked with READ LOCAL to permit concurrent inserts in the case of MyISAM tables. For transactional tables such as InnoDB, --single-transaction is a much better option than --lock-tables because it does not need to lock the tables at all.

    Because --lock-tables locks tables for each database separately, this option does not guarantee that the tables in the dump file are logically consistent between databases. Tables in different databases may be dumped in completely different states.

  • --log-error=file_name

    Log warnings and errors by appending them to the named file. The default is to do no logging.

  • --master-data[=value]

    Use this option to dump a master replication server to produce a dump file that can be used to set up another server as a slave of the master. It causes the dump output to include a CHANGE MASTER TO statement that indicates the binary log coordinates (file name and position) of the dumped server. These are the master server coordinates from which the slave should start replicating after you load the dump file into the slave.

    If the option value is 2, the CHANGE MASTER TO statement is written as an SQL comment, and thus is informative only; it has no effect when the dump file is reloaded. If the option value is 1, the statement is not written as a comment and takes effect when the dump file is reloaded. If no option value is specified, the default value is 1.

    This option requires the RELOAD privilege and the binary log must be enabled.

    The --master-data option automatically turns off --lock-tables. It also turns on --lock-all-tables, unless --single-transaction also is specified, in which case, a global read lock is acquired only for a short time at the beginning of the dump (see the description for --single-transaction). In all cases, any action on logs happens at the exact moment of the dump.

    It is also possible to set up a slave by dumping an existing slave of the master. To do this, use the following procedure on the existing slave:

    1. Stop the slave's SQL thread and get its current status:

      mysql> STOP SLAVE SQL_THREAD;
      mysql> SHOW SLAVE STATUS;
      
    2. From the output of the SHOW SLAVE STATUS statement, the binary log coordinates of the master server from which the new slave should start replicating are the values of the Relay_Master_Log_File and Exec_Master_Log_Pos fields. Denote those values as file_name and file_pos.

    3. Dump the slave server:

      shell> mysqldump --master-data=2 --all-databases > dumpfile
      

      Using --master-data=2 works only if binary logging has been enabled on the slave. Otherwise, mysqldump fails with the error Binlogging on server not active. In this case you must handle any locking issues in another manner, using one or more of --add-locks, --lock-tables, --lock-all-tables, or --single-transaction, as required by your application and environment.

    4. Restart the slave:

      mysql> START SLAVE;
      
    5. On the new slave, load the dump file:

      shell> mysql < dumpfile
      
    6. On the new slave, set the replication coordinates to those of the master server obtained earlier:

      mysql> CHANGE MASTER TO
          -> MASTER_LOG_FILE = 'file_name', MASTER_LOG_POS = file_pos;
      

      The CHANGE MASTER TO statement might also need other parameters, such as MASTER_HOST to point the slave to the correct master server host. Add any such parameters as necessary.

  • --no-autocommit

    Enclose the INSERT statements for each dumped table within SET autocommit = 0 and COMMIT statements.

  • --no-create-db, -n

    This option suppresses the CREATE DATABASE statements that are otherwise included in the output if the --databases or --all-databases option is given.

  • --no-create-info, -t

    Do not write CREATE TABLE statements that re-create each dumped table.

    Замечание

    This option does not not exclude statements creating log file groups or tablespaces from mysqldump output; however, you can use the --no-tablespaces option for this purpose.

  • --no-data, -d

    Do not write any table row information (that is, do not dump table contents). This is useful if you want to dump only the CREATE TABLE statement for the table (for example, to create an empty copy of the table by loading the dump file).

  • --no-set-names, -N

    This has the same effect as --skip-set-charset.

  • --no-tablespaces, -y

    This option suppresses all CREATE LOGFILE GROUP and CREATE TABLESPACE statements in the output of mysqldump.

  • --opt

    This option is shorthand. It is the same as specifying --add-drop-table --add-locks --create-options --disable-keys --extended-insert --lock-tables --quick --set-charset. It should give you a fast dump operation and produce a dump file that can be reloaded into a MySQL server quickly.

    The --opt option is enabled by default. Use --skip-opt to disable it. See the discussion at the beginning of this section for information about selectively enabling or disabling a subset of the options affected by --opt.

  • --order-by-primary

    Dump each table's rows sorted by its primary key, or by its first unique index, if such an index exists. This is useful when dumping a MyISAM table to be loaded into an InnoDB table, but will make the dump operation take considerably longer.

  • --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, mysqldump prompts for one.

    Specifying a password on the command line should be considered insecure. See Section 5.3.2.2, “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 using a named pipe. This option applies only if the server supports named-pipe connections.

  • --plugin-dir=path

    The directory in which to look for plugins. It may be necessary to specify this option if the --default-auth option is used to specify an authentication plugin but mysqldump does not find it. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.9.

  • --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 permissible values, see Section 4.2.2, “Connecting to the MySQL Server”.

  • --quick, -q

    This option is useful for dumping large tables. It forces mysqldump to retrieve rows for a table from the server a row at a time rather than retrieving the entire row set and buffering it in memory before writing it out.

  • --quote-names, -Q

    Quote identifiers (such as database, table, and column names) within “`” characters. If the ANSI_QUOTES SQL mode is enabled, identifiers are quoted within “"” characters. This option is enabled by default. It can be disabled with --skip-quote-names, but this option should be given after any option such as --compatible that may enable --quote-names.

  • --replace

    Write REPLACE statements rather than INSERT statements.

  • --result-file=file_name, -r file_name

    Direct output to a given file. This option should be used on Windows to prevent newline “\n” characters from being converted to “\r\n” carriage return/newline sequences. The result file is created and its previous contents overwritten, even if an error occurs while generating the dump.

  • --routines, -R

    Included stored routines (procedures and functions) for the dumped databases in the output. Use of this option requires the SELECT privilege for the mysql.proc table. The output generated by using --routines contains CREATE PROCEDURE and CREATE FUNCTION statements to re-create the routines. However, these statements do not include attributes such as the routine creation and modification timestamps. This means that when the routines are reloaded, they will be created with the timestamps equal to the reload time.

    If you require routines to be re-created with their original timestamp attributes, do not use --routines. Instead, dump and reload the contents of the mysql.proc table directly, using a MySQL account that has appropriate privileges for the mysql database.

    Prior to MySQL 5.5.21, this option had no effect when used together with the --xml option. (Bug #11760384, Bug #52792)

  • --set-charset

    Add SET NAMES default_character_set to the output. This option is enabled by default. To suppress the SET NAMES statement, use --skip-set-charset.

  • --single-transaction

    This option sends a START TRANSACTION SQL statement to the server before dumping data. It is useful only with transactional tables such as InnoDB, because then it dumps the consistent state of the database at the time when BEGIN was issued without blocking any applications.

    When using this option, you should keep in mind that only InnoDB tables are dumped in a consistent state. For example, any MyISAM or MEMORY tables dumped while using this option may still change state.

    While a --single-transaction dump is in process, to ensure a valid dump file (correct table contents and binary log coordinates), no other connection should use the following statements: ALTER TABLE, CREATE TABLE, DROP TABLE, RENAME TABLE, TRUNCATE TABLE. A consistent read is not isolated from those statements, so use of them on a table to be dumped can cause the SELECT that is performed by mysqldump to retrieve the table contents to obtain incorrect contents or fail.

    The --single-transaction option and the --lock-tables option are mutually exclusive because LOCK TABLES causes any pending transactions to be committed implicitly.

    This option is not supported for MySQL Cluster tables; the results cannot be guaranteed to be consistent due to the fact that the NDBCLUSTER storage engine supports only the READ_COMMITTED transaction isolation level. You should always use NDB backup and restore instead.

    To dump large tables, you should combine the --single-transaction option with --quick.

  • --skip-comments

    See the description for the --comments option.

  • --skip-opt

    See the description for the --opt option.

  • --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 using SSL and indicate where to find SSL keys and certificates. See Section 5.5.8.3, “SSL Command Options”.

  • --tab=path, -T path

    Produce tab-separated text-format data files. For each dumped table, mysqldump creates a tbl_name.sql file that contains the CREATE TABLE statement that creates the table, and the server writes a tbl_name.txt file that contains its data. The option value is the directory in which to write the files.

    Замечание

    This option should be used only when mysqldump is run on the same machine as the mysqld server. You must have the FILE privilege, and the server must have permission to write files in the directory that you specify.

    By default, the .txt data files are formatted using tab characters between column values and a newline at the end of each line. The format can be specified explicitly using the --fields-xxx and --lines-terminated-by options.

    Column values are converted to the character set specified by the --default-character-set option.

  • --tables

    Override the --databases or -B option. mysqldump regards all name arguments following the option as table names.

  • --triggers

    Include triggers for each dumped table in the output. This option is enabled by default; disable it with --skip-triggers.

  • --tz-utc

    This option enables TIMESTAMP columns to be dumped and reloaded between servers in different time zones. mysqldump sets its connection time zone to UTC and adds SET TIME_ZONE='+00:00' to the dump file. Without this option, TIMESTAMP columns are dumped and reloaded in the time zones local to the source and destination servers, which can cause the values to change if the servers are in different time zones. --tz-utc also protects against changes due to daylight saving time. --tz-utc is enabled by default. To disable it, use --skip-tz-utc.

  • --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.

  • --where='where_condition', -w 'where_condition'

    Dump only rows selected by the given WHERE condition. Quotes around the condition are mandatory if it contains spaces or other characters that are special to your command interpreter.

    Examples:

    --where="user='jimf'"
    -w"userid>1"
    -w"userid<1"
  • --xml, -X

    Write dump output as well-formed XML.

    NULL, 'NULL', and Empty Values: For a column named column_name, the NULL value, an empty string, and the string value 'NULL' are distinguished from one another in the output generated by this option as follows.

    Value:XML Representation:
    NULL (unknown value)

    <field name="column_name" xsi:nil="true" />

    '' (empty string)

    <field name="column_name"></field>

    'NULL' (string value)

    <field name="column_name">NULL</field>

    The output from the mysql client when run using the --xml option also follows the preceding rules. (See Section 4.5.1.1, “mysql Options”.)

    XML output from mysqldump includes the XML namespace, as shown here:

    shell> mysqldump --xml -u root world City
    <?xml version="1.0"?>
    <mysqldump xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <database name="world">
    <table_structure name="City">
    <field Field="ID" Type="int(11)" Null="NO" Key="PRI" Extra="auto_increment" />
    <field Field="Name" Type="char(35)" Null="NO" Key="" Default="" Extra="" />
    <field Field="CountryCode" Type="char(3)" Null="NO" Key="" Default="" Extra="" />
    <field Field="District" Type="char(20)" Null="NO" Key="" Default="" Extra="" />
    <field Field="Population" Type="int(11)" Null="NO" Key="" Default="0" Extra="" />
    <key Table="City" Non_unique="0" Key_name="PRIMARY" Seq_in_index="1" Column_name="ID"
    Collation="A" Cardinality="4079" Null="" Index_type="BTREE" Comment="" />
    <options Name="City" Engine="MyISAM" Version="10" Row_format="Fixed" Rows="4079"
    Avg_row_length="67" Data_length="273293" Max_data_length="18858823439613951"
    Index_length="43008" Data_free="0" Auto_increment="4080"
    Create_time="2007-03-31 01:47:01" Update_time="2007-03-31 01:47:02"
    Collation="latin1_swedish_ci" Create_options="" Comment="" />
    </table_structure>
    <table_data name="City">
    <row>
    <field name="ID">1</field>
    <field name="Name">Kabul</field>
    <field name="CountryCode">AFG</field>
    <field name="District">Kabol</field>
    <field name="Population">1780000</field>
    </row>
    
    ...
    
    <row>
    <field name="ID">4079</field>
    <field name="Name">Rafah</field>
    <field name="CountryCode">PSE</field>
    <field name="District">Rafah</field>
    <field name="Population">92020</field>
    </row>
    </table_data>
    </database>
    </mysqldump>
    

Prior to MySQL 5.5.21, this option prevented the --routines option from working correctly—that is, no stored routines, triggers, or events could be dumped in XML format. (Bug #11760384, Bug #52792)

You can also set the following variables by using --var_name=value syntax:

  • max_allowed_packet

    The maximum size of the buffer for client/server communication. The maximum is 1GB.

  • net_buffer_length

    The initial size of the buffer for client/server communication. When creating multiple-row INSERT statements (as with the --extended-insert or --opt option), mysqldump creates rows up to net_buffer_length length. If you increase this variable, you should also ensure that the net_buffer_length variable in the MySQL server is at least this large.

A common use of mysqldump is for making a backup of an entire database:

shell> mysqldump db_name > backup-file.sql

You can load the dump file back into the server like this:

shell> mysql db_name < backup-file.sql

Or like this:

shell> mysql -e "source /path-to-backup/backup-file.sql" db_name

mysqldump is also very useful for populating databases by copying data from one MySQL server to another:

shell> mysqldump --opt db_name | mysql --host=remote_host -C db_name

It is possible to dump several databases with one command:

shell> mysqldump --databases db_name1 [db_name2 ...] > my_databases.sql

To dump all databases, use the --all-databases option:

shell> mysqldump --all-databases > all_databases.sql

For InnoDB tables, mysqldump provides a way of making an online backup:

shell> mysqldump --all-databases --single-transaction > all_databases.sql

This backup acquires a global read lock on all tables (using FLUSH TABLES WITH READ LOCK) at the beginning of the dump. As soon as this lock has been acquired, the binary log coordinates are read and the lock is released. If long updating statements are running when the FLUSH statement is issued, the MySQL server may get stalled until those statements finish. After that, the dump becomes lock free and does not disturb reads and writes on the tables. If the update statements that the MySQL server receives are short (in terms of execution time), the initial lock period should not be noticeable, even with many updates.

For point-in-time recovery (also known as “roll-forward,” when you need to restore an old backup and replay the changes that happened since that backup), it is often useful to rotate the binary log (see Section 5.2.4, “The Binary Log”) or at least know the binary log coordinates to which the dump corresponds:

shell> mysqldump --all-databases --master-data=2 > all_databases.sql

Or:

shell> mysqldump --all-databases --flush-logs --master-data=2
              > all_databases.sql

The --master-data and --single-transaction options can be used simultaneously, which provides a convenient way to make an online backup suitable for use prior to point-in-time recovery if tables are stored using the InnoDB storage engine.

For more information on making backups, see Section 6.2, “Database Backup Methods”, and Section 6.3, “Пример Backup and Recovery Strategy”.

If you encounter problems backing up views, please read the section that covers restrictions on views which describes a workaround for backing up views when this fails due to insufficient privileges. See Section E.5, “Restrictions on Views”.

4.5.5. mysqlimport — A Data Import Program

The mysqlimport client provides a command-line interface to the LOAD DATA INFILE SQL statement. Most options to mysqlimport correspond directly to clauses of LOAD DATA INFILE syntax. See Section 12.2.6, “LOAD DATA INFILE Синтаксис”.

Invoke mysqlimport like this:

shell> mysqlimport [options] db_name textfile1 [textfile2 ...]

For each text file named on the command line, mysqlimport strips any extension from the file name and uses the result to determine the name of the table into which to import the file's contents. For example, files named patient.txt, patient.text, and patient all would be imported into a table named patient.

For additional information about mysqldump, see Section 6.4, “Using mysqldump for Backups”.

mysqlimport supports the following options, which can be specified on the command line or in the [mysqlimport] and [client] groups of an option file. mysqlimport 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 4.6. mysqlimport Options

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--columns=column_listcolumnsThis option takes a comma-separated list of column names as its value   
--compresscompressCompress all information sent between the client and the server   
--debug[=debug_options]debugWrite a debugging log   
--debug-checkdebug-checkPrint debugging information when the program exits   
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits   
--default-auth=plugindefault-auth=pluginThe authentication plugin to use5.5.10  
--default-character-set=charset_namedefault-character-setUse charset_name as the default character set   
--deletedeleteEmpty the table before importing the text file   
--fields-enclosed-by=stringfields-enclosed-byThis option has the same meaning as the corresponding clause for LOAD DATA INFILE   
--fields-escaped-byfields-escaped-byThis option has the same meaning as the corresponding clause for LOAD DATA INFILE   
--fields-optionally-enclosed-by=stringfields-optionally-enclosed-byThis option has the same meaning as the corresponding clause for LOAD DATA INFILE   
--fields-terminated-by=stringfields-terminated-by-- This option has the same meaning as the corresponding clause for LOAD DATA INFILE   
--forceforceContinue even if an SQL error occurs   
--help Display help message and exit   
--host=host_namehostConnect to the MySQL server on the given host   
--ignoreignoreSee the description for the --replace option   
--ignore-lines=#ignore-linesIgnore the first N lines of the data file   
--lines-terminated-by=stringlines-terminated-byThis option has the same meaning as the corresponding clause for LOAD DATA INFILE   
--locallocalRead input files locally from the client host   
--lock-tableslock-tablesLock all tables for writing before processing any text files   
--low-prioritylow-priorityUse LOW_PRIORITY when loading the table.   
--password[=password]passwordThe password to use when connecting to the server   
--pipe On Windows, connect to server using a named pipe   
--plugin-dir=pathplugin-dir=pathThe directory where plugins are located5.5.10  
--port=port_numportThe TCP/IP port number to use for the connection   
--protocol=typeprotocolThe connection protocol to use   
--replacereplaceThe --replace and --ignore options control handling of input rows that duplicate existing rows on unique key values   
--silentsilentProduce output only when errors occur   
--socket=pathsocketFor connections to localhost   
--ssl-ca=file_namessl-caThe path to a file that contains a list of trusted SSL CAs   
--ssl-capath=dir_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   
--use-threads=#use-threadsThe number of threads for parallel file-loading   
--user=user_name,userThe MySQL user name to use when connecting to the server   
--verbose Verbose mode   
--version Display version information and exit   

Here is a sample session that demonstrates use of mysqlimport:

shell> mysql -e 'CREATE TABLE imptest(id INT, n VARCHAR(30))' test
shell> ed
a
100     Max Sydow
101     Count Dracula
.
w imptest.txt
32
q
shell> od -c imptest.txt
0000000   1   0   0  \t   M   a   x       S   y   d   o   w  \n   1   0
0000020   1  \t   C   o   u   n   t       D   r   a   c   u   l   a  \n
0000040
shell> mysqlimport --local test imptest.txt
test.imptest: Records: 2  Deleted: 0  Skipped: 0  Warnings: 0
shell> mysql -e 'SELECT * FROM imptest' test
+------+---------------+
| id   | n             |
+------+---------------+
|  100 | Max Sydow     |
|  101 | Count Dracula |
+------+---------------+

4.5.6. mysqlshow — Display Database, Table, and Column Information

The mysqlshow client can be used to quickly see which databases exist, their tables, or a table's columns or indexes.

mysqlshow provides a command-line interface to several SQL SHOW statements. See Section 12.7.5, “SHOW Синтаксис”. The same information can be obtained by using those statements directly. For example, you can issue them from the mysql client program.

Invoke mysqlshow like this:

shell> mysqlshow [options] [db_name [tbl_name [col_name]]]
  • If no database is given, a list of database names is shown.

  • If no table is given, all matching tables in the database are shown.

  • If no column is given, all matching columns and column types in the table are shown.

The output displays only the names of those databases, tables, or columns for which you have some privileges.

If the last argument contains shell or SQL wildcard characters (“*”, “?”, “%”, or “_”), only those names that are matched by the wildcard are shown. If a database name contains any underscores, those should be escaped with a backslash (some Unix shells require two) to get a list of the proper tables or columns. “*” and “?” characters are converted into SQL “%” and “_” wildcard characters. This might cause some confusion when you try to display the columns for a table with a “_” in the name, because in this case, mysqlshow shows you only the table names that match the pattern. This is easily fixed by adding an extra “%” last on the command line as a separate argument.

mysqlshow supports the following options, which can be specified on the command line or in the [mysqlshow] and [client] groups of an option file. mysqlshow 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 4.7. mysqlshow Options

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--bind-address=ip_addressbind-addressUse the specified network interface to connect to the MySQL Server5.5.8  
--compresscompressCompress all information sent between the client and the server   
--countcountShow the number of rows per table   
--debug[=debug_options]debugWrite a debugging log   
--debug-checkdebug-checkPrint debugging information when the program exits   
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits   
--default-auth=plugindefault-auth=pluginThe authentication plugin to use5.5.10  
--default-character-set=charset_namedefault-character-setUse charset_name as the default character set   
--help Display help message and exit   
--host=host_namehostConnect to the MySQL server on the given host   
--keyskeysShow table indexes   
--password[=password]passwordThe password to use when connecting to the server   
--pipe On Windows, connect to server using a named pipe   
--plugin-dir=pathplugin-dir=pathThe directory where plugins are located5.5.10  
--port=port_numportThe TCP/IP port number to use for the connection   
--protocol=typeprotocolThe connection protocol to use   
--show-table-type Show a column indicating the table type   
--socket=pathsocketFor connections to localhost   
--ssl-ca=file_namessl-caThe path to a file that contains a list of trusted SSL CAs   
--ssl-capath=dir_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   
--statusstatusDisplay extra information about each table   
--user=user_name,userThe MySQL user name to use when connecting to the server   
--verbose Verbose mode   
--version Display version information and exit   

4.5.7. mysqlslap — Load Emulation Client

mysqlslap is a diagnostic program designed to emulate client load for a MySQL server and to report the timing of each stage. It works as if multiple clients are accessing the server.

Invoke mysqlslap like this:

shell> mysqlslap [options]

Some options such as --create or --query enable you to specify a string containing an SQL statement or a file containing statements. If you specify a file, by default it must contain one statement per line. (That is, the implicit statement delimiter is the newline character.) Use the --delimiter option to specify a different delimiter, which enables you to specify statements that span multiple lines or place multiple statements on a single line. You cannot include comments in a file; mysqlslap does not understand them.

mysqlslap runs in three stages:

  1. Create schema, table, and optionally any stored programs or data you want to using for the test. This stage uses a single client connection.

  2. Run the load test. This stage can use many client connections.

  3. Clean up (disconnect, drop table if specified). This stage uses a single client connection.

Examples:

Supply your own create and query SQL statements, with 50 clients querying and 200 selects for each:

mysqlslap --delimiter=";" \
  --create="CREATE TABLE a (b int);INSERT INTO a VALUES (23)" \
  --query="SELECT * FROM a" --concurrency=50 --iterations=200

Let mysqlslap build the query SQL statement with a table of two INT columns and three VARCHAR columns. Use five clients querying 20 times each. Do not create the table or insert the data (that is, use the previous test's schema and data):

mysqlslap --concurrency=5 --iterations=20 \
  --number-int-cols=2 --number-char-cols=3 \
  --auto-generate-sql

Tell the program to load the create, insert, and query SQL statements from the specified files, where the create.sql file has multiple table creation statements delimited by ';' and multiple insert statements delimited by ';'. The --query file will have multiple queries delimited by ';'. Run all the load statements, then run all the queries in the query file with five clients (five times each):

mysqlslap --concurrency=5 \
  --iterations=5 --query=query.sql --create=create.sql \
  --delimiter=";"

mysqlslap supports the following options, which can be specified on the command line or in the [mysqlslap] and [client] groups of an option file. mysqlslap 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 4.8. mysqlslap Options

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--auto-generate-sqlauto-generate-sqlGenerate SQL statements automatically when they are not supplied in files or using command options   
--auto-generate-sql-add-autoincrementauto-generate-sql-add-autoincrementAdd AUTO_INCREMENT column to automatically generated tables   
--auto-generate-sql-execute-number=#auto-generate-sql-execute-numberSpecify how many queries to generate automatically   
--auto-generate-sql-guid-primaryauto-generate-sql-guid-primaryAdd a GUID-based primary key to automatically generated tables   
--auto-generate-sql-load-type=typeauto-generate-sql-load-typeSpecify how many queries to generate automatically   
--auto-generate-sql-secondary-indexes=#auto-generate-sql-secondary-indexesSpecify how many secondary indexes to add to automatically generated tables   
--auto-generate-sql-unique-query-number=#auto-generate-sql-unique-query-numberHow many different queries to generate for automatic tests.   
--auto-generate-sql-unique-write-number=#auto-generate-sql-unique-write-numberHow many different queries to generate for --auto-generate-sql-write-number   
--auto-generate-sql-write-number=#auto-generate-sql-write-numberHow many row inserts to perform on each thread   
--commit=#commitHow many statements to execute before committing.   
--compresscompressCompress all information sent between the client and the server   
--concurrency=#concurrencyThe number of clients to simulate when issuing the SELECT statement   
--create=valuecreateThe file or string containing the statement to use for creating the table   
--create-and-drop-schema=valuecreate-and-drop-schemaThe schema in which to run the tests; dropped at the end of the test run5.5.12  
--create-schema=valuecreate-schemaThe schema in which to run the tests   
--csv=[file]csvGenerate output in comma-separated values format   
--debug[=debug_options]debugWrite a debugging log   
--debug-checkdebug-checkPrint debugging information when the program exits   
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits   
--default-auth=plugindefault-auth=pluginThe authentication plugin to use5.5.10  
--delimiter=strdelimiterThe delimiter to use in SQL statements   
--detach=#detachDetach (close and reopen) each connection after each N statements   
--engine=engine_nameengineThe storage engine to use for creating the table   
--help Display help message and exit   
--host=host_namehostConnect to the MySQL server on the given host   
--iterations=#iterationsThe number of times to run the tests   
--number-char-cols=#number-char-colsThe number of VARCHAR columns to use if --auto-generate-sql is specified   
--number-int-cols=#number-int-colsThe number of INT columns to use if --auto-generate-sql is specified   
--number-of-queries=#number-of-queriesLimit each client to approximately this number of queries   
--only-printonly-printDo not connect to databases. mysqlslap only prints what it would have done   
--password[=password]passwordThe password to use when connecting to the server   
--pipe On Windows, connect to server using a named pipe   
--plugin-dir=pathplugin-dir=pathThe directory where plugins are located5.5.10  
--port=port_numportThe TCP/IP port number to use for the connection   
--post-query=valuepost-queryThe file or string containing the statement to execute after the tests have completed   
--post-system=strpost-systemThe string to execute using system() after the tests have completed   
--pre-query=valuepre-queryThe file or string containing the statement to execute before running the tests   
--pre-system=strpre-systemThe string to execute using system() before running the tests   
--protocol=typeprotocolThe connection protocol to use   
--query=valuequeryThe file or string containing the SELECT statement to use for retrieving data   
--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=dir_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   
  • --help, -?

    Display a help message and exit.

  • --auto-generate-sql, -a

    Generate SQL statements automatically when they are not supplied in files or using command options.

  • --auto-generate-sql-add-autoincrement

    Add an AUTO_INCREMENT column to automatically generated tables.

  • --auto-generate-sql-execute-number=N

    Specify how many queries to generate automatically.

  • --auto-generate-sql-guid-primary

    Add a GUID-based primary key to automatically generated tables.

  • --auto-generate-sql-load-type=type

    Specify the test load type. The permissible values are read (scan tables), write (insert into tables), key (read primary keys), update (update primary keys), or mixed (half inserts, half scanning selects). The default is mixed.

  • --auto-generate-sql-secondary-indexes=N

    Specify how many secondary indexes to add to automatically generated tables. By default, none are added.

  • --auto-generate-sql-unique-query-number=N

    How many different queries to generate for automatic tests. For example, if you run a key test that performs 1000 selects, you can use this option with a value of 1000 to run 1000 unique queries, or with a value of 50 to perform 50 different selects. The default is 10.

  • --auto-generate-sql-unique-write-number=N

    How many different queries to generate for --auto-generate-sql-write-number. The default is 10.

  • --auto-generate-sql-write-number=N

    How many row inserts to perform on each thread. The default is 100.

  • --commit=N

    How many statements to execute before committing. The default is 0 (no commits are done).

  • --compress, -C

    Compress all information sent between the client and the server if both support compression.

  • --concurrency=N, -c N

    The number of clients to simulate when issuing the SELECT statement.

  • --create=value

    The file or string containing the statement to use for creating the table.

  • --create-and-drop-schema=value

    The schema in which to run the tests. mysqlslap drops the schema at the end of the test run. This option was added in MySQL 5.5.12.

  • --create-schema=value

    The schema in which to run the tests.

    Замечание

    If the --auto-generate-sql option is also given, mysqlslap drops the schema at the end of the test run. To avoid this, use the --create-and-drop-schema option instead.

  • --csv[=file_name]

    Generate output in comma-separated values format. The output goes to the named file, or to the standard output if no file 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/mysqlslap.trace'.

  • --debug-check

    Print some debugging information when the program exits.

  • --debug-info, -T

    Print debugging information and memory and CPU usage statistics when the program exits.

  • --default-auth=plugin

    The client-side authentication plugin to use. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.10.

  • --delimiter=str, -F str

    The delimiter to use in SQL statements supplied in files or using command options.

  • --detach=N

    Detach (close and reopen) each connection after each N statements. The default is 0 (connections are not detached).

  • --engine=engine_name, -e engine_name

    The storage engine to use for creating tables.

  • --host=host_name, -h host_name

    Connect to the MySQL server on the given host.

  • --iterations=N, -i N

    The number of times to run the tests.

  • --number-char-cols=N, -x N

    The number of VARCHAR columns to use if --auto-generate-sql is specified.

  • --number-int-cols=N, -y N

    The number of INT columns to use if --auto-generate-sql is specified.

  • --number-of-queries=N

    Limit each client to approximately this many queries. Query counting takes into account the statement delimiter. For example, if you invoke mysqlslap as follows, the ; delimiter is recognized so that each instance of the query string counts as two queries. As a result, 5 rows (not 10) are inserted.

    shell> mysqlslap --delimiter=";" --number-of-queries=10
             --query="use test;insert into t values(null)"
    
  • --only-print

    Do not connect to databases. mysqlslap only prints what it would have done.

  • --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, mysqlslap prompts for one.

    Specifying a password on the command line should be considered insecure. See Section 5.3.2.2, “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 using a named pipe. This option applies only if the server supports named-pipe connections.

  • --plugin-dir=path

    The directory in which to look for plugins. It may be necessary to specify this option if the --default-auth option is used to specify an authentication plugin but mysqlslap does not find it. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.10.

  • --port=port_num, -P port_num

    The TCP/IP port number to use for the connection.

  • --post-query=value

    The file or string containing the statement to execute after the tests have completed. This execution is not counted for timing purposes.

  • --shared-memory-base-name=name

    On Windows, the shared-memory name to use, for connections made using shared memory to a local server. This option applies only if the server supports shared-memory connections.

  • --post-system=str

    The string to execute using system() after the tests have completed. This execution is not counted for timing purposes.

  • --pre-query=value

    The file or string containing the statement to execute before running the tests. This execution is not counted for timing purposes.

  • --pre-system=str

    The string to execute using system() before running the tests. This execution is not counted for timing purposes.

  • --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 permissible values, see Section 4.2.2, “Connecting to the MySQL Server”.

  • --query=value, -q value

    The file or string containing the SELECT statement to use for retrieving data.

  • --silent, -s

    Silent mode. No output.

  • --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 using SSL and indicate where to find SSL keys and certificates. See Section 5.5.8.3, “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. This option can be used multiple times to increase the amount of information.

  • --version, -V

    Display version information and exit.

4.6. MySQL Administrative and Utility Programs

This section describes administrative programs and programs that perform miscellaneous utility operations.

4.6.1. innochecksum — Offline InnoDB File Checksum Utility

innochecksum prints checksums for InnoDB files. This tool reads an InnoDB tablespace file, calculates the checksum for each page, compares the calculated checksum to the stored checksum, and reports mismatches, which indicate damaged pages. It was originally developed to speed up verifying the integrity of tablespace files after power outages but can also be used after file copies. Because checksum mismatches will cause InnoDB to deliberately shut down a running server, it can be preferable to use this tool rather than waiting for a server in production usage to encounter the damaged pages.

innochecksum cannot be used on tablespace files that the server already has open. For such files, you should use CHECK TABLE to check tables within the tablespace.

If checksum mismatches are found, you would normally restore the tablespace from backup or start the server and attempt to use mysqldump to make a backup of the tables within the tablespace.

Invoke innochecksum like this:

shell> innochecksum [options] file_name

innochecksum supports the following options. For options that refer to page numbers, the numbers are zero-based.

  • -c

    Print a count of the number of pages in the file.

  • -d

    Debug mode; prints checksums for each page.

  • -e num

    End at this page number.

  • -p num

    Check only this page number.

  • -s num

    Start at this page number.

  • -v

    Verbose mode; print a progress indicator every five seconds.

4.6.2. myisam_ftdump — Display Full-Text Index information

myisam_ftdump displays information about FULLTEXT indexes in MyISAM tables. It reads the MyISAM index file directly, so it must be run on the server host where the table is located. Before using myisam_ftdump, be sure to issue a FLUSH TABLES statement first if the server is running.

myisam_ftdump scans and dumps the entire index, which is not particularly fast. On the other hand, the distribution of words changes infrequently, so it need not be run often.

Invoke myisam_ftdump like this:

shell> myisam_ftdump [options] tbl_name index_num

The tbl_name argument should be the name of a MyISAM table. You can also specify a table by naming its index file (the file with the .MYI suffix). If you do not invoke myisam_ftdump in the directory where the table files are located, the table or index file name must be preceded by the path name to the table's database directory. Index numbers begin with 0.

Пример: Suppose that the test database contains a table named mytexttablel that has the following definition:

CREATE TABLE mytexttable
(
  id   INT NOT NULL,
  txt  TEXT NOT NULL,
  PRIMARY KEY (id),
  FULLTEXT (txt)
) ENGINE=MyISAM;

The index on id is index 0 and the FULLTEXT index on txt is index 1. If your working directory is the test database directory, invoke myisam_ftdump as follows:

shell> myisam_ftdump mytexttable 1

If the path name to the test database directory is /usr/local/mysql/data/test, you can also specify the table name argument using that path name. This is useful if you do not invoke myisam_ftdump in the database directory:

shell> myisam_ftdump /usr/local/mysql/data/test/mytexttable 1

You can use myisam_ftdump to generate a list of index entries in order of frequency of occurrence like this:

shell> myisam_ftdump -c mytexttable 1 | sort -r

myisam_ftdump supports the following options:

  • --help, -h -?

    Display a help message and exit.

  • --count, -c

    Calculate per-word statistics (counts and global weights).

  • --dump, -d

    Dump the index, including data offsets and word weights.

  • --length, -l

    Report the length distribution.

  • --stats, -s

    Report global index statistics. This is the default operation if no other operation is specified.

  • --verbose, -v

    Verbose mode. Print more output about what the program does.

4.6.3. myisamchk — MyISAM Table-Maintenance Utility

The myisamchk utility gets information about your database tables or checks, repairs, or optimizes them. myisamchk works with MyISAM tables (tables that have .MYD and .MYI files for storing data and indexes).

You can also use the CHECK TABLE and REPAIR TABLE statements to check and repair MyISAM tables. See Section 12.7.2.2, “CHECK TABLE Синтаксис”, and Section 12.7.2.5, “REPAIR TABLE Синтаксис”.

The use of myisamchk with partitioned tables is not supported.

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.

Invoke myisamchk like this:

shell> myisamchk [options] tbl_name ...

The options specify what you want myisamchk to do. They are described in the following sections. You can also get a list of options by invoking myisamchk --help.

With no options, myisamchk simply checks your table as the default operation. To get more information or to tell myisamchk to take corrective action, specify options as described in the following discussion.

tbl_name is the database table you want to check or repair. If you run myisamchk somewhere other than in the database directory, you must specify the path to the database directory, because myisamchk has no idea where the database is located. In fact, myisamchk does not actually care whether the files you are working on are located in a database directory. You can copy the files that correspond to a database table into some other location and perform recovery operations on them there.

You can name several tables on the myisamchk command line if you wish. You can also specify a table by naming its index file (the file with the .MYI suffix). This enables you to specify all tables in a directory by using the pattern *.MYI. For example, if you are in a database directory, you can check all the MyISAM tables in that directory like this:

shell> myisamchk *.MYI

If you are not in the database directory, you can check all the tables there by specifying the path to the directory:

shell> myisamchk /path/to/database_dir/*.MYI

You can even check all tables in all databases by specifying a wildcard with the path to the MySQL data directory:

shell> myisamchk /path/to/datadir/*/*.MYI

The recommended way to quickly check all MyISAM tables is:

shell> myisamchk --silent --fast /path/to/datadir/*/*.MYI

If you want to check all MyISAM tables and repair any that are corrupted, you can use the following command:

shell> myisamchk --silent --force --fast --update-state \
          --key_buffer_size=64M --sort_buffer_size=64M \
          --read_buffer_size=1M --write_buffer_size=1M \
          /path/to/datadir/*/*.MYI

This command assumes that you have more than 64MB free. For more information about memory allocation with myisamchk, see Section 4.6.3.6, “myisamchk Memory Usage”.

For additional information about using myisamchk, see Section 6.6, “MyISAM Table Maintenance and Crash Recovery”.

Important

You must ensure that no other program is using the tables while you are running myisamchk. The most effective means of doing so is to shut down the MySQL server while running myisamchk, or to lock all tables that myisamchk is being used on.

Otherwise, when you run myisamchk, it may display the following error message:

warning: clients are using or haven't closed the table properly

This means that you are trying to check a table that has been updated by another program (such as the mysqld server) that hasn't yet closed the file or that has died without closing the file properly, which can sometimes lead to the corruption of one or more MyISAM tables.

If mysqld is running, you must force it to flush any table modifications that are still buffered in memory by using FLUSH TABLES. You should then ensure that no one is using the tables while you are running myisamchk

However, the easiest way to avoid this problem is to use CHECK TABLE instead of myisamchk to check tables. See Section 12.7.2.2, “CHECK TABLE Синтаксис”.

myisamchk supports the following options, which can be specified on the command line or in the [myisamchk] group of an option file. myisamchk 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 4.9. myisamchk Options

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--analyzeanalyzeAnalyze the distribution of key values   
--backupbackupMake a backup of the .MYD file as file_name-time.BAK   
--block-search=offsetblock-searchFind the record that a block at the given offset belongs to   
--checkcheckCheck the table for errors   
--check-only-changedcheck-only-changedCheck only tables that have changed since the last check   
--correct-checksumcorrect-checksumCorrect the checksum information for the table   
--data-file-length=lendata-file-lengthMaximum length of the data file (when re-creating data file when it is full)   
--debug[=debug_options]debugWrite a debugging log   
decode_bits=#decode_bitsDecode_bits   
--descriptiondescriptionPrint some descriptive information about the table   
--extend-checkextend-checkDo very thorough table check or repair that tries to recover every possible row from the data file   
--fastfastCheck only tables that haven't been closed properly   
--forceforceDo a repair operation automatically if myisamchk finds any errors in the table   
--forceforce-recoverOverwrite old temporary files. For use with the -r or -o option   
ft_max_word_len=#ft_max_word_lenMaximum word length for FULLTEXT indexes   
ft_min_word_len=#ft_min_word_lenMinimum word length for FULLTEXT indexes   
ft_stopword_file=valueft_stopword_fileUse stopwords from this file instead of built-in list   
--HELP Display help message and exit   
--help Display help message and exit   
--informationinformationPrint informational statistics about the table that is checked   
key_buffer_size=#key_buffer_sizeThe size of the buffer used for index blocks for MyISAM tables   
--keys-used=valkeys-usedA bit-value that indicates which indexes to update   
--max-record-length=lenmax-record-lengthSkip rows larger than the given length if myisamchk cannot allocate memory to hold them   
--medium-checkmedium-checkDo a check that is faster than an --extend-check operation   
myisam_block_size=#myisam_block_sizeBlock size to be used for MyISAM index pages   
--parallel-recoverparallel-recoverUses the same technique as -r and -n, but creates all the keys in parallel, using different threads (beta)   
--quickquickAchieve a faster repair by not modifying the data file.   
read_buffer_size=#read_buffer_sizeEach thread that does a sequential scan allocates a buffer of this size for each table it scans   
--read-onlyread-onlyDon't mark the table as checked   
--recoverrecoverDo a repair that can fix almost any problem except unique keys that aren't unique   
--safe-recoversafe-recoverDo a repair using an old recovery method that reads through all rows in order and updates all index trees based on the rows found   
--set-auto-increment[=value]set-auto-incrementForce AUTO_INCREMENT numbering for new records to start at the given value   
--set-collation=nameset-collationSpecify the collation to use for sorting table indexes   
--silentsilentSilent mode   
sort_buffer_size=#sort_buffer_sizeThe buffer that is allocated when sorting the index when doing a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE   
--sort-indexsort-indexSort the index tree blocks in high-low order   
sort_key_blocks=#sort_key_blockssort_key_blocks   
--sort-records=#sort-recordsSort records according to a particular index   
--sort-recoversort-recoverForce myisamchk to use sorting to resolve the keys even if the temporary files would be very large   
stats_method=valuestats_methodSpecifies how MyISAM index statistics collection code should treat NULLs   
--tmpdir=pathtmpdirPath of the directory to be used for storing temporary files   
--unpackunpackUnpack a table that was packed with myisampack   
--update-stateupdate-stateStore information in the .MYI file to indicate when the table was checked and whether the table crashed   
--verbose Verbose mode   
--version Display version information and exit   
write_buffer_size=#write_buffer_sizeWrite buffer size   

4.6.3.1. myisamchk General Options

The options described in this section can be used for any type of table maintenance operation performed by myisamchk. The sections following this one describe options that pertain only to specific operations, such as table checking or repairing.

  • --help, -?

    Display a help message and exit. Options are grouped by type of operation.

  • --HELP, -H

    Display a help message and exit. Options are presented in a single list.

  • --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/myisamchk.trace'.

  • --silent, -s

    Silent mode. Write output only when errors occur. You can use -s twice (-ss) to make myisamchk very silent.

  • --verbose, -v

    Verbose mode. Print more information about what the program does. This can be used with -d and -e. Use -v multiple times (-vv, -vvv) for even more output.

  • --version, -V

    Display version information and exit.

  • --wait, -w

    Instead of terminating with an error if the table is locked, wait until the table is unlocked before continuing. If you are running mysqld with external locking disabled, the table can be locked only by another myisamchk command.

You can also set the following variables by using --var_name=value syntax:

VariableDefault Value
decode_bits9
ft_max_word_lenversion-dependent
ft_min_word_len4
ft_stopword_filebuilt-in list
key_buffer_size523264
myisam_block_size1024
read_buffer_size262136
sort_buffer_size2097144
sort_key_blocks16
stats_methodnulls_unequal
write_buffer_size262136

The possible myisamchk variables and their default values can be examined with myisamchk --help:

sort_buffer_size is used when the keys are repaired by sorting keys, which is the normal case when you use --recover.

key_buffer_size is used when you are checking the table with --extend-check or when the keys are repaired by inserting keys row by row into the table (like when doing normal inserts). Repairing through the key buffer is used in the following cases:

  • You use --safe-recover.

  • The temporary files needed to sort the keys would be more than twice as big as when creating the key file directly. This is often the case when you have large key values for CHAR, VARCHAR, or TEXT columns, because the sort operation needs to store the complete key values as it proceeds. If you have lots of temporary space and you can force myisamchk to repair by sorting, you can use the --sort-recover option.

Repairing through the key buffer takes much less disk space than using sorting, but is also much slower.

If you want a faster repair, set the key_buffer_size and sort_buffer_size variables to about 25% of your available memory. You can set both variables to large values, because only one of them is used at a time.

myisam_block_size is the size used for index blocks.

stats_method influences how NULL values are treated for index statistics collection when the --analyze option is given. It acts like the myisam_stats_method system variable. For more information, see the description of myisam_stats_method in Section 5.1.3, “Server System Variables”, and Section 7.3.7, “InnoDB and MyISAM Index Statistics Collection”.

ft_min_word_len and ft_max_word_len indicate the minimum and maximum word length for FULLTEXT indexes. ft_stopword_file names the stopword file. These need to be set under the following circumstances.

If you use myisamchk to perform an operation that modifies table indexes (such as repair or analyze), the FULLTEXT indexes are rebuilt using the default full-text parameter values for minimum and maximum word length and the stopword file unless you specify otherwise. This can result in queries failing.

The problem occurs because these parameters are known only by the server. They are not stored in MyISAM index files. To avoid the problem if you have modified the minimum or maximum word length or the stopword file in the server, specify the same ft_min_word_len, ft_max_word_len, and ft_stopword_file values to myisamchk that you use for mysqld. For example, if you have set the minimum word length to 3, you can repair a table with myisamchk like this:

shell> myisamchk --recover --ft_min_word_len=3 tbl_name.MYI

To ensure that myisamchk and the server use the same values for full-text parameters, you can place each one in both the [mysqld] and [myisamchk] sections of an option file:

[mysqld]
ft_min_word_len=3

[myisamchk]
ft_min_word_len=3

An alternative to using myisamchk is to use the REPAIR TABLE, ANALYZE TABLE, OPTIMIZE TABLE, or ALTER TABLE. These statements are performed by the server, which knows the proper full-text parameter values to use.

4.6.3.2. myisamchk Check Options

myisamchk supports the following options for table checking operations:

  • --check, -c

    Check the table for errors. This is the default operation if you specify no option that selects an operation type explicitly.

  • --check-only-changed, -C

    Check only tables that have changed since the last check.

  • --extend-check, -e

    Check the table very thoroughly. This is quite slow if the table has many indexes. This option should only be used in extreme cases. Normally, myisamchk or myisamchk --medium-check should be able to determine whether there are any errors in the table.

    If you are using --extend-check and have plenty of memory, setting the key_buffer_size variable to a large value helps the repair operation run faster.

    See also the description of this option under table repair options.

    For a description of the output format, see Section 4.6.3.5, “Obtaining Table Information with myisamchk.

  • --fast, -F

    Check only tables that haven't been closed properly.

  • --force, -f

    Do a repair operation automatically if myisamchk finds any errors in the table. The repair type is the same as that specified with the --recover or -r option.

  • --information, -i

    Print informational statistics about the table that is checked.

  • --medium-check, -m

    Do a check that is faster than an --extend-check operation. This finds only 99.99% of all errors, which should be good enough in most cases.

  • --read-only, -T

    Do not mark the table as checked. This is useful if you use myisamchk to check a table that is in use by some other application that does not use locking, such as mysqld when run with external locking disabled.

  • --update-state, -U

    Store information in the .MYI file to indicate when the table was checked and whether the table crashed. This should be used to get full benefit of the --check-only-changed option, but you shouldn't use this option if the mysqld server is using the table and you are running it with external locking disabled.

4.6.3.3. myisamchk Repair Options

myisamchk supports the following options for table repair operations (operations performed when an option such as --recover or --safe-recover is given):

  • --backup, -B

    Make a backup of the .MYD file as file_name-time.BAK

  • --character-sets-dir=path

    The directory where character sets are installed. See Section 9.5, “Character Set Configuration”.

  • --correct-checksum

    Correct the checksum information for the table.

  • --data-file-length=len, -D len

    The maximum length of the data file (when re-creating data file when it is “full”).

  • --extend-check, -e

    Do a repair that tries to recover every possible row from the data file. Normally, this also finds a lot of garbage rows. Do not use this option unless you are desperate.

    See also the description of this option under table checking options.

    For a description of the output format, see Section 4.6.3.5, “Obtaining Table Information with myisamchk.

  • --force, -f

    Overwrite old intermediate files (files with names like tbl_name.TMD) instead of aborting.

  • --keys-used=val, -k val

    For myisamchk, the option value is a bit-value that indicates which indexes to update. Each binary bit of the option value corresponds to a table index, where the first index is bit 0. An option value of 0 disables updates to all indexes, which can be used to get faster inserts. Deactivated indexes can be reactivated by using myisamchk -r.

  • --no-symlinks, -l

    Do not follow symbolic links. Normally myisamchk repairs the table that a symlink points to. This option does not exist as of MySQL 4.0 because versions from 4.0 on do not remove symlinks during repair operations.

  • --max-record-length=len

    Skip rows larger than the given length if myisamchk cannot allocate memory to hold them.

  • --parallel-recover, -p

    Use the same technique as -r and -n, but create all the keys in parallel, using different threads. This is beta-quality code. Use at your own risk!

  • --quick, -q

    Achieve a faster repair by modifying only the index file, not the data file. You can specify this option twice to force myisamchk to modify the original data file in case of duplicate keys.

  • --recover, -r

    Do a repair that can fix almost any problem except unique keys that are not unique (which is an extremely unlikely error with MyISAM tables). If you want to recover a table, this is the option to try first. You should try --safe-recover only if myisamchk reports that the table cannot be recovered using --recover. (In the unlikely case that --recover fails, the data file remains intact.)

    If you have lots of memory, you should increase the value of sort_buffer_size.

  • --safe-recover, -o

    Do a repair using an old recovery method that reads through all rows in order and updates all index trees based on the rows found. This is an order of magnitude slower than --recover, but can handle a couple of very unlikely cases that --recover cannot. This recovery method also uses much less disk space than --recover. Normally, you should repair first using --recover, and then with --safe-recover only if --recover fails.

    If you have lots of memory, you should increase the value of key_buffer_size.

  • --set-character-set=name

    Change the character set used by the table indexes. This option was replaced by --set-collation in MySQL 5.0.3.

  • --set-collation=name

    Specify the collation to use for sorting table indexes. The character set name is implied by the first part of the collation name.

  • --sort-recover, -n

    Force myisamchk to use sorting to resolve the keys even if the temporary files would be very large.

  • --tmpdir=path, -t path

    The path of the directory to be used for storing temporary files. If this is not set, myisamchk uses the value of the TMPDIR environment variable. --tmpdir can be set to a list of directory paths that are used successively in round-robin fashion for creating temporary files. The separator character between directory names is the colon (“:”) on Unix and the semicolon (“;”) on Windows.

  • --unpack, -u

    Unpack a table that was packed with myisampack.

4.6.3.4. Other myisamchk Options

myisamchk supports the following options for actions other than table checks and repairs:

  • --analyze, -a

    Analyze the distribution of key values. This improves join performance by enabling the join optimizer to better choose the order in which to join the tables and which indexes it should use. To obtain information about the key distribution, use a myisamchk --description --verbose tbl_name command or the SHOW INDEX FROM tbl_name statement.

  • --block-search=offset, -b offset

    Find the record that a block at the given offset belongs to.

  • --description, -d

    Print some descriptive information about the table. Specifying the --verbose option once or twice produces additional information. See Section 4.6.3.5, “Obtaining Table Information with myisamchk.

  • --set-auto-increment[=value], -A[value]

    Force AUTO_INCREMENT numbering for new records to start at the given value (or higher, if there are existing records with AUTO_INCREMENT values this large). If value is not specified, AUTO_INCREMENT numbers for new records begin with the largest value currently in the table, plus one.

  • --sort-index, -S

    Sort the index tree blocks in high-low order. This optimizes seeks and makes table scans that use indexes faster.

  • --sort-records=N, -R N

    Sort records according to a particular index. This makes your data much more localized and may speed up range-based SELECT and ORDER BY operations that use this index. (The first time you use this option to sort a table, it may be very slow.) To determine a table's index numbers, use SHOW INDEX, which displays a table's indexes in the same order that myisamchk sees them. Indexes are numbered beginning with 1.

    If keys are not packed (PACK_KEYS=0), they have the same length, so when myisamchk sorts and moves records, it just overwrites record offsets in the index. If keys are packed (PACK_KEYS=1), myisamchk must unpack key blocks first, then re-create indexes and pack the key blocks again. (In this case, re-creating indexes is faster than updating offsets for each index.)

4.6.3.5. Obtaining Table Information with myisamchk

To obtain a description of a MyISAM table or statistics about it, use the commands shown here. The output from these commands is explained later in this section.

  • myisamchk -d tbl_name

    Runs myisamchk in “describe mode” to produce a description of your table. If you start the MySQL server with external locking disabled, myisamchk may report an error for a table that is updated while it runs. However, because myisamchk does not change the table in describe mode, there is no risk of destroying data.

  • myisamchk -dv tbl_name

    Adding -v runs myisamchk in verbose mode so that it produces more information about the table. Adding -v a second time produces even more information.

  • myisamchk -eis tbl_name

    Shows only the most important information from a table. This operation is slow because it must read the entire table.

  • myisamchk -eiv tbl_name

    This is like -eis, but tells you what is being done.

The tbl_name argument can be either the name of a MyISAM table or the name of its index file, as described in Section 4.6.3, “myisamchk — MyISAM Table-Maintenance Utility”. Multiple tbl_name arguments can be given.

Suppose that a table named person has the following structure. (The MAX_ROWS table option is included so that in the example output from myisamchk shown later, some values are smaller and fit the output format more easily.)

CREATE TABLE person
(
  id         INT NOT NULL AUTO_INCREMENT,
  last_name  VARCHAR(20) NOT NULL,
  first_name VARCHAR(20) NOT NULL,
  birth      DATE,
  death      DATE,
  PRIMARY KEY (id),
  INDEX (last_name, first_name),
  INDEX (birth)
) MAX_ROWS = 1000000;

Suppose also that the table has these data and index file sizes:

-rw-rw----  1 mysql  mysql  9347072 Aug 19 11:47 person.MYD
-rw-rw----  1 mysql  mysql  6066176 Aug 19 11:47 person.MYI

Пример of myisamchk -dvv output:

MyISAM file:         person
Record format:       Packed
Character set:       latin1_swedish_ci (8)
File-version:        1
Creation time:       2009-08-19 16:47:41
Recover time:        2009-08-19 16:47:56
Status:              checked,analyzed,optimized keys
Auto increment key:              1  Last value:                306688
Data records:               306688  Deleted blocks:                 0
Datafile parts:             306688  Deleted data:                   0
Datafile pointer (bytes):        4  Keyfile pointer (bytes):        3
Datafile length:           9347072  Keyfile length:           6066176
Max datafile length:    4294967294  Max keyfile length:   17179868159
Recordlength:                   54

table description:
Key Start Len Index   Type                 Rec/key         Root  Blocksize
1   2     4   unique  long                       1        99328       1024
2   6     20  multip. varchar prefix           512      3563520       1024
    27    20          varchar                  512
3   48    3   multip. uint24 NULL           306688      6065152       1024

Field Start Length Nullpos Nullbit Type
1     1     1
2     2     4                      no zeros
3     6     21                     varchar
4     27    21                     varchar
5     48    3      1       1       no zeros
6     51    3      1       2       no zeros

Explanations for the types of information myisamchk produces are given here. “Keyfile” refers to the index file. “Record” and “row” are synonymous, as are “field” and “column.

The initial part of the table description contains these values:

  • MyISAM file

    Name of the MyISAM (index) file.

  • Record format

    The format used to store table rows. The preceding examples use Fixed length. Other possible values are Compressed and Packed. (Packed corresponds to what SHOW TABLE STATUS reports as Dynamic.)

  • Chararacter set

    The table default character set.

  • File-version

    Version of MyISAM format. Currently always 1.

  • Creation time

    When the data file was created.

  • Recover time

    When the index/data file was last reconstructed.

  • Status

    Table status flags. Possible values are crashed, open, changed, analyzed, optimized keys, and sorted index pages.

  • Auto increment key, Last value

    The key number associated the table's AUTO_INCREMENT column, and the most recently generated value for this column. These fields do not appear if there is no such column.

  • Data records

    The number of rows in the table.

  • Deleted blocks

    How many deleted blocks still have reserved space. You can optimize your table to minimize this space. See Section 6.6.4, “MyISAM Table Optimization”.

  • Datafile parts

    For dynamic-row format, this indicates how many data blocks there are. For an optimized table without fragmented rows, this is the same as Data records.

  • Deleted data

    How many bytes of unreclaimed deleted data there are. You can optimize your table to minimize this space. See Section 6.6.4, “MyISAM Table Optimization”.

  • Datafile pointer

    The size of the data file pointer, in bytes. It is usually 2, 3, 4, or 5 bytes. Most tables manage with 2 bytes, but this cannot be controlled from MySQL yet. For fixed tables, this is a row address. For dynamic tables, this is a byte address.

  • Keyfile pointer

    The size of the index file pointer, in bytes. It is usually 1, 2, or 3 bytes. Most tables manage with 2 bytes, but this is calculated automatically by MySQL. It is always a block address.

  • Max datafile length

    How long the table data file can become, in bytes.

  • Max keyfile length

    How long the table index file can become, in bytes.

  • Recordlength

    How much space each row takes, in bytes.

The table description part of the output includes a list of all keys in the table. For each key, myisamchk displays some low-level information:

  • Key

    This key's number. This value is shown only for the first column of the key. If this value is missing, the line corresponds to the second or later column of a multiple-column key. For the table shown in the example, there are two table description lines for the second index. This indicates that it is a multiple-part index with two parts.

  • Start

    Where in the row this portion of the index starts.

  • Len

    How long this portion of the index is. For packed numbers, this should always be the full length of the column. For strings, it may be shorter than the full length of the indexed column, because you can index a prefix of a string column. The total length of a multiple-part key is the sum of the Len values for all key parts.

  • Index

    Whether a key value can exist multiple times in the index. Possible values are unique or multip. (multiple).

  • Type

    What data type this portion of the index has. This is a MyISAM data type with the possible values packed, stripped, or empty.

  • Root

    Address of the root index block.

  • Blocksize

    The size of each index block. By default this is 1024, but the value may be changed at compile time when MySQL is built from source.

  • Rec/key

    This is a statistical value used by the optimizer. It tells how many rows there are per value for this index. A unique index always has a value of 1. This may be updated after a table is loaded (or greatly changed) with myisamchk -a. If this is not updated at all, a default value of 30 is given.

The last part of the output provides information about each column:

  • Field

    The column number.

  • Start

    The byte position of the column within table rows.

  • Length

    The length of the column in bytes.

  • Nullpos, Nullbit

    For columns that can be NULL, MyISAM stores NULL values as a flag in a byte. Depending on how many nullable columns there are, there can be one or more bytes used for this purpose. The Nullpos and Nullbit values, if nonempty, indicate which byte and bit contains that flag indicating whether the column is NULL.

    The position and number of bytes used to store NULL flags is shown in the line for field 1. This is why there are six Field lines for the person table even though it has only five columns.

  • Type

    The data type. The value may contain any of the following descriptors:

    • constant

      All rows have the same value.

    • no endspace

      Do not store endspace.

    • no endspace, not_always

      Do not store endspace and do not do endspace compression for all values.

    • no endspace, no empty

      Do not store endspace. Do not store empty values.

    • table-lookup

      The column was converted to an ENUM.

    • zerofill(N)

      The most significant N bytes in the value are always 0 and are not stored.

    • no zeros

      Do not store zeros.

    • always zero

      Zero values are stored using one bit.

  • Huff tree

    The number of the Huffman tree associated with the column.

  • Bits

    The number of bits used in the Huffman tree.

The Huff tree and Bits fields are displayed if the table has been compressed with myisampack. See Section 4.6.5, “myisampack — Generate Compressed, Read-Only MyISAM Tables”, for an example of this information.

Пример of myisamchk -eiv output:

Checking MyISAM file: person
Data records:  306688   Deleted blocks:       0
- check file-size
- check record delete-chain
No recordlinks
- check key delete-chain
block_size 1024:
- check index reference
- check data record references index: 1
Key:  1:  Keyblocks used:  98%  Packed:    0%  Max levels:  3
- check data record references index: 2
Key:  2:  Keyblocks used:  99%  Packed:   97%  Max levels:  3
- check data record references index: 3
Key:  3:  Keyblocks used:  98%  Packed:  -14%  Max levels:  3
Total:    Keyblocks used:  98%  Packed:   89%

- check records and index references*** LOTS OF ROW NUMBERS DELETED ***

Records:            306688  M.recordlength:       25  Packed:            83%
Recordspace used:       97% Empty space:           2% Blocks/Record:   1.00
Record blocks:      306688  Delete blocks:         0
Record data:       7934464  Deleted data:          0
Lost space:         256512  Linkdata:        1156096

User time 43.08, System time 1.68
Maximum resident set size 0, Integral resident set size 0
Non-physical pagefaults 0, Physical pagefaults 0, Swaps 0
Blocks in 0 out 7, Messages in 0 out 0, Signals 0
Voluntary context switches 0, Involuntary context switches 0
Maximum memory usage: 1046926 bytes (1023k)

myisamchk -eiv output includes the following information:

  • Data records

    The number of rows in the table.

  • Deleted blocks

    How many deleted blocks still have reserved space. You can optimize your table to minimize this space. See Section 6.6.4, “MyISAM Table Optimization”.

  • Key

    The key number.

  • Keyblocks used

    What percentage of the keyblocks are used. When a table has just been reorganized with myisamchk, the values are very high (very near theoretical maximum).

  • Packed

    MySQL tries to pack key values that have a common suffix. This can only be used for indexes on CHAR and VARCHAR columns. For long indexed strings that have similar leftmost parts, this can significantly reduce the space used. In the preceding example, the second key is 40 bytes long and a 97% reduction in space is achieved.

  • Max levels

    How deep the B-tree for this key is. Large tables with long key values get high values.

  • Records

    How many rows are in the table.

  • M.recordlength

    The average row length. This is the exact row length for tables with fixed-length rows, because all rows have the same length.

  • Packed

    MySQL strips spaces from the end of strings. The Packed value indicates the percentage of savings achieved by doing this.

  • Recordspace used

    What percentage of the data file is used.

  • Empty space

    What percentage of the data file is unused.

  • Blocks/Record

    Average number of blocks per row (that is, how many links a fragmented row is composed of). This is always 1.0 for fixed-format tables. This value should stay as close to 1.0 as possible. If it gets too large, you can reorganize the table. See Section 6.6.4, “MyISAM Table Optimization”.

  • Recordblocks

    How many blocks (links) are used. For fixed-format tables, this is the same as the number of rows.

  • Deleteblocks

    How many blocks (links) are deleted.

  • Recorddata

    How many bytes in the data file are used.

  • Deleted data

    How many bytes in the data file are deleted (unused).

  • Lost space

    If a row is updated to a shorter length, some space is lost. This is the sum of all such losses, in bytes.

  • Linkdata

    When the dynamic table format is used, row fragments are linked with pointers (4 to 7 bytes each). Linkdata is the sum of the amount of storage used by all such pointers.

4.6.3.6. myisamchk Memory Usage

Memory allocation is important when you run myisamchk. myisamchk uses no more memory than its memory-related variables are set to. If you are going to use myisamchk on very large tables, you should first decide how much memory you want it to use. The default is to use only about 3MB to perform repairs. By using larger values, you can get myisamchk to operate faster. For example, if you have more than 512MB RAM available, you could use options such as these (in addition to any other options you might specify):

shell> myisamchk --sort_buffer_size=256M \
           --key_buffer_size=512M \
           --read_buffer_size=64M \
           --write_buffer_size=64M ...

Using --sort_buffer_size=16M is probably enough for most cases.

Be aware that myisamchk uses temporary files in TMPDIR. If TMPDIR points to a memory file system, out of memory errors can easily occur. If this happens, run myisamchk with the --tmpdir=path option to specify a directory located on a file system that has more space.

When performing repair operations, myisamchk also needs a lot of disk space:

  • Twice the size of the data file (the original file and a copy). This space is not needed if you do a repair with --quick; in this case, only the index file is re-created. This space must be available on the same file system as the original data file, as the copy is created in the same directory as the original.

  • Space for the new index file that replaces the old one. The old index file is truncated at the start of the repair operation, so you usually ignore this space. This space must be available on the same file system as the original data file.

  • When using --recover or --sort-recover (but not when using --safe-recover), you need space on disk for sorting. This space is allocated in the temporary directory (specified by TMPDIR or --tmpdir=path). The following formula yields the amount of space required:

    (largest_key + row_pointer_length) * number_of_rows * 2
    

    You can check the length of the keys and the row_pointer_length with myisamchk -dv tbl_name (see Section 4.6.3.5, “Obtaining Table Information with myisamchk). The row_pointer_length and number_of_rows values are the Datafile pointer and Data records values in the table description. To determine the largest_key value, check the Key lines in the table description. The Len column indicates the number of bytes for each key part. For a multiple-column index, the key size is the sum of the Len values for all key parts.

If you have a problem with disk space during repair, you can try --safe-recover instead of --recover.

4.6.4. myisamlog — Display MyISAM Log File Contents

myisamlog processes the contents of a MyISAM log file.

Invoke myisamlog like this:

shell> myisamlog [options] [log_file [tbl_name] ...]
shell> isamlog [options] [log_file [tbl_name] ...]

The default operation is update (-u). If a recovery is done (-r), all writes and possibly updates and deletes are done and errors are only counted. The default log file name is myisam.log for myisamlog and isam.log for isamlog if no log_file argument is given. If tables are named on the command line, only those tables are updated.

myisamlog supports the following options:

  • -?, -I

    Display a help message and exit.

  • -c N

    Execute only N commands.

  • -f N

    Specify the maximum number of open files.

  • -i

    Display extra information before exiting.

  • -o offset

    Specify the starting offset.

  • -p N

    Remove N components from path.

  • -r

    Perform a recovery operation.

  • -R record_pos_file record_pos

    Specify record position file and record position.

  • -u

    Perform an update operation.

  • -v

    Verbose mode. Print more output about what the program does. This option can be given multiple times to produce more and more output.

  • -w write_file

    Specify the write file.

  • -V

    Display version information.

4.6.5. myisampack — Generate Compressed, Read-Only MyISAM Tables

The myisampack utility compresses MyISAM tables. myisampack works by compressing each column in the table separately. Usually, myisampack packs the data file 40% to 70%.

When the table is used later, the server reads into memory the information needed to decompress columns. This results in much better performance when accessing individual rows, because you only have to uncompress exactly one row.

MySQL uses mmap() when possible to perform memory mapping on compressed tables. If mmap() does not work, MySQL falls back to normal read/write file operations.

Please note the following:

  • If the mysqld server was invoked with external locking disabled, it is not a good idea to invoke myisampack if the table might be updated by the server during the packing process. It is safest to compress tables with the server stopped.

  • After packing a table, it becomes read only. This is generally intended (such as when accessing packed tables on a CD).

Invoke myisampack like this:

shell> myisampack [options] file_name ...

Each file name argument should be the name of an index (.MYI) file. If you are not in the database directory, you should specify the path name to the file. It is permissible to omit the .MYI extension.

After you compress a table with myisampack, you should use myisamchk -rq to rebuild its indexes. Section 4.6.3, “myisamchk — MyISAM Table-Maintenance Utility”.

myisampack supports the following options. 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”.

  • --help, -?

    Display a help message and exit.

  • --backup, -b

    Make a backup of each table's data file using the name tbl_name.OLD.

  • --character-sets-dir=path

    The directory where character sets are installed. See Section 9.5, “Character Set Configuration”.

  • --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'.

  • --force, -f

    Produce a packed table even if it becomes larger than the original or if the intermediate file from an earlier invocation of myisampack exists. (myisampack creates an intermediate file named tbl_name.TMD in the database directory while it compresses the table. If you kill myisampack, the .TMD file might not be deleted.) Normally, myisampack exits with an error if it finds that tbl_name.TMD exists. With --force, myisampack packs the table anyway.

  • --join=big_tbl_name, -j big_tbl_name

    Join all tables named on the command line into a single packed table big_tbl_name. All tables that are to be combined must have identical structure (same column names and types, same indexes, and so forth).

    big_tbl_name must not exist prior to the join operation. All source tables named on the command line to be merged into big_tbl_name must exist. The source tables are read for the join operation but not modified. The join operation does not create a .frm file for big_tbl_name, so after the join operation finishes, copy the .frm file from one of the source tables and name it big_tbl_name.frm.

  • --silent, -s

    Silent mode. Write output only when errors occur.

  • --test, -t

    Do not actually pack the table, just test packing it.

  • --tmpdir=path, -T path

    Use the named directory as the location where myisampack creates temporary files.

  • --verbose, -v

    Verbose mode. Write information about the progress of the packing operation and its result.

  • --version, -V

    Display version information and exit.

  • --wait, -w

    Wait and retry if the table is in use. If the mysqld server was invoked with external locking disabled, it is not a good idea to invoke myisampack if the table might be updated by the server during the packing process.

The following sequence of commands illustrates a typical table compression session:

shell> ls -l station.*
-rw-rw-r--   1 monty    my         994128 Apr 17 19:00 station.MYD
-rw-rw-r--   1 monty    my          53248 Apr 17 19:00 station.MYI
-rw-rw-r--   1 monty    my           5767 Apr 17 19:00 station.frm

shell> myisamchk -dvv station

MyISAM file:     station
Isam-version:  2
Creation time: 1996-03-13 10:08:58
Recover time:  1997-02-02  3:06:43
Data records:              1192  Deleted blocks:              0
Datafile parts:            1192  Deleted data:                0
Datafile pointer (bytes):     2  Keyfile pointer (bytes):     2
Max datafile length:   54657023  Max keyfile length:   33554431
Recordlength:               834
Record format: Fixed length

table description:
Key Start Len Index   Type                 Root  Blocksize    Rec/key
1   2     4   unique  unsigned long        1024       1024          1
2   32    30  multip. text                10240       1024          1

Field Start Length Type
1     1     1
2     2     4
3     6     4
4     10    1
5     11    20
6     31    1
7     32    30
8     62    35
9     97    35
10    132   35
11    167   4
12    171   16
13    187   35
14    222   4
15    226   16
16    242   20
17    262   20
18    282   20
19    302   30
20    332   4
21    336   4
22    340   1
23    341   8
24    349   8
25    357   8
26    365   2
27    367   2
28    369   4
29    373   4
30    377   1
31    378   2
32    380   8
33    388   4
34    392   4
35    396   4
36    400   4
37    404   1
38    405   4
39    409   4
40    413   4
41    417   4
42    421   4
43    425   4
44    429   20
45    449   30
46    479   1
47    480   1
48    481   79
49    560   79
50    639   79
51    718   79
52    797   8
53    805   1
54    806   1
55    807   20
56    827   4
57    831   4

shell> myisampack station.MYI
Compressing station.MYI: (1192 records)
- Calculating statistics

normal:     20  empty-space:   16  empty-zero:     12  empty-fill:  11
pre-space:   0  end-space:     12  table-lookups:   5  zero:         7
Original trees:  57  After join: 17
- Compressing file
87.14%
Remember to run myisamchk -rq on compressed tables

shell> ls -l station.*
-rw-rw-r--   1 monty    my         127874 Apr 17 19:00 station.MYD
-rw-rw-r--   1 monty    my          55296 Apr 17 19:04 station.MYI
-rw-rw-r--   1 monty    my           5767 Apr 17 19:00 station.frm

shell> myisamchk -dvv station

MyISAM file:     station
Isam-version:  2
Creation time: 1996-03-13 10:08:58
Recover time:  1997-04-17 19:04:26
Data records:               1192  Deleted blocks:              0
Datafile parts:             1192  Deleted data:                0
Datafile pointer (bytes):      3  Keyfile pointer (bytes):     1
Max datafile length:    16777215  Max keyfile length:     131071
Recordlength:                834
Record format: Compressed

table description:
Key Start Len Index   Type                 Root  Blocksize    Rec/key
1   2     4   unique  unsigned long       10240       1024          1
2   32    30  multip. text                54272       1024          1

Field Start Length Type                         Huff tree  Bits
1     1     1      constant                             1     0
2     2     4      zerofill(1)                          2     9
3     6     4      no zeros, zerofill(1)                2     9
4     10    1                                           3     9
5     11    20     table-lookup                         4     0
6     31    1                                           3     9
7     32    30     no endspace, not_always              5     9
8     62    35     no endspace, not_always, no empty    6     9
9     97    35     no empty                             7     9
10    132   35     no endspace, not_always, no empty    6     9
11    167   4      zerofill(1)                          2     9
12    171   16     no endspace, not_always, no empty    5     9
13    187   35     no endspace, not_always, no empty    6     9
14    222   4      zerofill(1)                          2     9
15    226   16     no endspace, not_always, no empty    5     9
16    242   20     no endspace, not_always              8     9
17    262   20     no endspace, no empty                8     9
18    282   20     no endspace, no empty                5     9
19    302   30     no endspace, no empty                6     9
20    332   4      always zero                          2     9
21    336   4      always zero                          2     9
22    340   1                                           3     9
23    341   8      table-lookup                         9     0
24    349   8      table-lookup                        10     0
25    357   8      always zero                          2     9
26    365   2                                           2     9
27    367   2      no zeros, zerofill(1)                2     9
28    369   4      no zeros, zerofill(1)                2     9
29    373   4      table-lookup                        11     0
30    377   1                                           3     9
31    378   2      no zeros, zerofill(1)                2     9
32    380   8      no zeros                             2     9
33    388   4      always zero                          2     9
34    392   4      table-lookup                        12     0
35    396   4      no zeros, zerofill(1)               13     9
36    400   4      no zeros, zerofill(1)                2     9
37    404   1                                           2     9
38    405   4      no zeros                             2     9
39    409   4      always zero                          2     9
40    413   4      no zeros                             2     9
41    417   4      always zero                          2     9
42    421   4      no zeros                             2     9
43    425   4      always zero                          2     9
44    429   20     no empty                             3     9
45    449   30     no empty                             3     9
46    479   1                                          14     4
47    480   1                                          14     4
48    481   79     no endspace, no empty               15     9
49    560   79     no empty                             2     9
50    639   79     no empty                             2     9
51    718   79     no endspace                         16     9
52    797   8      no empty                             2     9
53    805   1                                          17     1
54    806   1                                           3     9
55    807   20     no empty                             3     9
56    827   4      no zeros, zerofill(2)                2     9
57    831   4      no zeros, zerofill(1)                2     9

myisampack displays the following kinds of information:

  • normal

    The number of columns for which no extra packing is used.

  • empty-space

    The number of columns containing values that are only spaces. These occupy one bit.

  • empty-zero

    The number of columns containing values that are only binary zeros. These occupy one bit.

  • empty-fill

    The number of integer columns that do not occupy the full byte range of their type. These are changed to a smaller type. For example, a BIGINT column (eight bytes) can be stored as a TINYINT column (one byte) if all its values are in the range from -128 to 127.

  • pre-space

    The number of decimal columns that are stored with leading spaces. In this case, each value contains a count for the number of leading spaces.

  • end-space

    The number of columns that have a lot of trailing spaces. In this case, each value contains a count for the number of trailing spaces.

  • table-lookup

    The column had only a small number of different values, which were converted to an ENUM before Huffman compression.

  • zero

    The number of columns for which all values are zero.

  • Original trees

    The initial number of Huffman trees.

  • After join

    The number of distinct Huffman trees left after joining trees to save some header space.

After a table has been compressed, the Field lines displayed by myisamchk -dvv include additional information about each column:

  • Type

    The data type. The value may contain any of the following descriptors:

    • constant

      All rows have the same value.

    • no endspace

      Do not store endspace.

    • no endspace, not_always

      Do not store endspace and do not do endspace compression for all values.

    • no endspace, no empty

      Do not store endspace. Do not store empty values.

    • table-lookup

      The column was converted to an ENUM.

    • zerofill(N)

      The most significant N bytes in the value are always 0 and are not stored.

    • no zeros

      Do not store zeros.

    • always zero

      Zero values are stored using one bit.

  • Huff tree

    The number of the Huffman tree associated with the column.

  • Bits

    The number of bits used in the Huffman tree.

After you run myisampack, you must run myisamchk to re-create any indexes. At this time, you can also sort the index blocks and create statistics needed for the MySQL optimizer to work more efficiently:

shell> myisamchk -rq --sort-index --analyze tbl_name.MYI

After you have installed the packed table into the MySQL database directory, you should execute mysqladmin flush-tables to force mysqld to start using the new table.

To unpack a packed table, use the --unpack option to myisamchk.

4.6.6. mysqlaccess — Client for Checking Access Privileges

mysqlaccess is a diagnostic tool that Yves Carlier has provided for the MySQL distribution. It checks the access privileges for a host name, user name, and database combination. Note that mysqlaccess checks access using only the user, db, and host tables. It does not check table, column, or routine privileges specified in the tables_priv, columns_priv, or procs_priv tables.

Invoke mysqlaccess like this:

shell> mysqlaccess [host_name [user_name [db_name]]] [options]

mysqlaccess supports the following options.

Table 4.10. mysqlaccess Options

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--briefbriefGenerate reports in single-line tabular format   
--commitcommitCopy the new access privileges from the temporary tables to the original grant tables   
--copycopyReload the temporary grant tables from original ones   
--db=db_namedbSpecify the database name   
--debug=#debugSpecify the debug level   
--help Display help message and exit   
--host=host_namehostConnect to the MySQL server on the given host   
--howtohowtoDisplay some examples that show how to use mysqlaccess   
--old_serverold_serverAssume that the server is an old MySQL server (prior to MySQL 3.21)   
--password[=password]passwordThe password to use when connecting to the server   
--planplanDisplay suggestions and ideas for future releases   
--previewpreviewShow the privilege differences after making changes to the temporary grant tables   
--relnotesrelnotesDisplay the release notes   
--rhost=host_namerhostConnect to the MySQL server on the given host   
--rollbackrollbackUndo the most recent changes to the temporary grant tables.   
--spassword[=password]spasswordThe password to use when connecting to the server as the superuser   
--superuser=user_namesuperuserSpecify the user name for connecting as the superuser   
--tabletableGenerate reports in table format   
--user=user_name,userThe MySQL user name to use when connecting   
--version Display version information and exit   

If your MySQL distribution is installed in some nonstandard location, you must change the location where mysqlaccess expects to find the mysql client. Edit the mysqlaccess script at approximately line 18. Search for a line that looks like this:

$MYSQL     = '/usr/local/bin/mysql';    # path to mysql executable

Change the path to reflect the location where mysql actually is stored on your system. If you do not do this, a Broken pipe error will occur when you run mysqlaccess.

4.6.7. mysqlbinlog — Utility for Processing Binary Log Files

The server's binary log consists of files containing “events” that describe modifications to database contents. The server writes these files in binary format. To display their contents in text format, use the mysqlbinlog utility. You can also use mysqlbinlog to display the contents of relay log files written by a slave server in a replication setup because relay logs have the same format as binary logs. The binary log and relay log are discussed further in Section 5.2.4, “The Binary Log”, and Section 15.2.2, “Replication Relay and Status Logs”.

Invoke mysqlbinlog like this:

shell> mysqlbinlog [options] log_file ...

For example, to display the contents of the binary log file named binlog.000003, use this command:

shell> mysqlbinlog binlog.0000003

The output includes events contained in binlog.000003. For statement-based logging, event information includes the SQL statement, the ID of the server on which it was executed, the timestamp when the statement was executed, how much time it took, and so forth. For row-based logging, the event indicates a row change rather than an SQL statement. See Section 15.1.2, “Replication Formats”, for information about logging modes.

Events are preceded by header comments that provide additional information. For example:

# at 141
#100309  9:28:36 server id 123  end_log_pos 245
  Query thread_id=3350  exec_time=11  error_code=0

In the first line, the number following at indicates the starting position of the event in the binary log file.

The second line starts with a date and time indicating when the statement started on the server where the event originated. For replication, this timestamp is propagated to slave servers. server id is the server_id value of the server where the event originated. end_log_pos indicates where the next event starts (that is, it is the end position of the current event + 1). thread_id indicates which thread executed the event. exec_time is the time spent executing the event, on a master server. On a slave, it is the difference of the end execution time on the slave minus the beginning execution time on the master. The difference serves as an indicator of how much replication lags behind the master. error_code indicates the result from executing the event. Zero means that no error occurred.

The output from mysqlbinlog can be re-executed (for example, by using it as input to mysql) to redo the statements in the log. This is useful for recovery operations after a server crash. For other usage examples, see the discussion later in this section and in Section 6.5, “Point-in-Time (Incremental) Recovery Using the Binary Log”.

Normally, you use mysqlbinlog to read binary log files directly and apply them to the local MySQL server. It is also possible to read binary logs from a remote server by using the --read-from-remote-server option. To read remote binary logs, the connection parameter options can be given to indicate how to connect to the server. These options are --host, --password, --port, --protocol, --socket, and --user; they are ignored except when you also use the --read-from-remote-server option.

mysqlbinlog supports the following options, which can be specified on the command line or in the [mysqlbinlog] and [client] groups of an option file. mysqlbinlog 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 4.11. mysqlbinlog Options

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--base64-output[=value]base64-outputPrint binary log entries using base-64 encoding   
--character-sets-dir=pathcharacter-sets-dirThe directory where character sets are installed   
--database=db_namedatabaseList entries for just this database   
--debug[=debug_options]debugWrite a debugging log   
--debug-checkdebug-checkPrint debugging information when the program exits   
--debug-infodebug-infoPrint debugging information, memory and CPU statistics when the program exits   
--default-auth=plugindefault-auth=pluginThe authentication plugin to use5.5.10  
--disable-log-bindisable-log-binDisable binary logging   
--force-readforce-readIf mysqlbinlog reads a binary log event that it does not recognize, it prints a warning   
--help Display help message and exit   
--hexdumphexdumpDisplay a hex dump of the log in comments   
--host=host_namehostConnect to the MySQL server on the given host   
--local-load=pathlocal-loadPrepare local temporary files for LOAD DATA INFILE in the specified directory   
--offset=#offsetSkip the first N entries in the log   
--password[=password]passwordThe password to use when connecting to the server   
--plugin-dir=pathplugin-dir=pathThe directory where plugins are located5.5.10  
--port=port_numportThe TCP/IP port number to use for the connection   
--protocol=typeprotocolThe connection protocol to use   
--read-from-remote-serverread-from-remote-serverRead the binary log from a MySQL server rather than reading a local log file   
--result-file=nameresult-fileDirect output to the given file   
--server-id=idserver-idExtract only those events created by the server having the given server ID   
--set-charset=charset_nameset-charsetAdd a SET NAMES charset_name statement to the output   
--short-formshort-formDisplay only the statements contained in the log   
--socket=pathsocketFor connections to localhost   
--start-datetime=datetimestart-datetimeStart reading the binary log at the first event having a timestamp equal to or later than the datetime argument   
--start-position=#start-positionStart reading the binary log at the first event having a position equal to or greater than the argument   
--stop-datetime=datetimestop-datetimeStop reading the binary log at the first event having a timestamp equal to or greater than the datetime argument   
--stop-position=#stop-positionStop reading the binary log at the first event having a position equal to or greater than the argument   
--to-last-logto-last-logDo not stop at the end of the requested binary log from a MySQL server, but rather continue printing until the end of the last binary log   
--user=user_name,userThe MySQL user name to use when connecting to the server   
--verbose Reconstruct row events as SQL statements   
--version Display version information and exit   
  • --help, -?

    Display a help message and exit.

  • --base64-output[=value]

    This option determines when events should be displayed encoded as base-64 strings using BINLOG statements. The option has these permissible values (not case sensitive):

    • AUTO ("automatic") or UNSPEC ("unspecified") displays BINLOG statements automatically when necessary (that is, for format description events and row events). If no --base64-output option is given, the effect is the same as --base64-output=AUTO.

      Замечание

      Automatic BINLOG display is the only safe behavior if you intend to use the output of mysqlbinlog to re-execute binary log file contents. The other option values are intended only for debugging or testing purposes because they may produce output that does not include all events in executable form.

    • ALWAYS displays BINLOG statements whenever possible. If the --base64-output option is given without a value, the effect is the same as --base64-output=ALWAYS.

      Замечание

      Changes to replication in MySQL 5.6 make output generated by this option unusable, so ALWAYS is deprecated as of MySQL 5.5.8 and will be an invalid value in MySQL 5.6

    • NEVER causes BINLOG statements not to be displayed. mysqlbinlog exits with an error if a row event is found that must be displayed using BINLOG.

    • DECODE-ROWS specifies to mysqlbinlog that you intend for row events to be decoded and displayed as commented SQL statements by also specifying the --verbose option. Like NEVER, DECODE-ROWS suppresses display of BINLOG statements, but unlike NEVER, it does not exit with an error if a row event is found.

    For examples that show the effect of --base64-output and --verbose on row event output, see Section 4.6.7.2, “mysqlbinlog Row Event Display”.

  • --bind-address=ip_address

    On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server.

    This option is supported beginning with MySQL 5.5.8.

  • --character-sets-dir=path

    The directory where character sets are installed. See Section 9.5, “Character Set Configuration”.

  • --database=db_name, -d db_name

    This option causes mysqlbinlog to output entries from the binary log (local log only) that occur while db_name is been selected as the default database by USE.

    The --database option for mysqlbinlog is similar to the --binlog-do-db option for mysqld, but can be used to specify only one database. If --database is given multiple times, only the last instance is used.

    The effects of this option depend on whether the statement-based or row-based logging format is in use, in the same way that the effects of --binlog-do-db depend on whether statement-based or row-based logging is in use.

    Statement-based logging.  The --database option works as follows:

    • While db_name is the default database, statements are output whether they modify tables in db_name or a different database.

    • Unless db_name is selected as the default database, statements are not output, even if they modify tables in db_name.

    • There is an exception for CREATE DATABASE, ALTER DATABASE, and DROP DATABASE. The database being created, altered, or dropped is considered to be the default database when determining whether to output the statement.

    Suppose that the binary log was created by executing these statements using statement-based-logging:

    INSERT INTO test.t1 (i) VALUES(100);
    INSERT INTO db2.t2 (j)  VALUES(200);
    USE test;
    INSERT INTO test.t1 (i) VALUES(101);
    INSERT INTO t1 (i)      VALUES(102);
    INSERT INTO db2.t2 (j)  VALUES(201);
    USE db2;
    INSERT INTO test.t1 (i) VALUES(103);
    INSERT INTO db2.t2 (j)  VALUES(202);
    INSERT INTO t2 (j)      VALUES(203);

    mysqlbinlog --database=test does not output the first two INSERT statements because there is no default database. It outputs the three INSERT statements following USE test, but not the three INSERT statements following USE db2.

    mysqlbinlog --database=db2 does not output the first two INSERT statements because there is no default database. It does not output the three INSERT statements following USE test, but does output the three INSERT statements following USE db2.

    Row-based logging.  mysqlbinlog outputs only entries that change tables belonging to db_name. The default database has no effect on this. Suppose that the binary log just described was created using row-based logging rather than statement-based logging. mysqlbinlog --database=test outputs only those entries that modify t1 in the test database, regardless of whether USE was issued or what the default database is.

    If a server is running with binlog_format set to MIXED and you want it to be possible to use mysqlbinlog with the --database option, you must ensure that tables that are modified are in the database selected by USE. (In particular, no cross-database updates should be used.)

  • --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/mysqlbinlog.trace'.

  • --debug-check

    Print some debugging information when the program exits.

  • --debug-info

    Print debugging information and memory and CPU usage statistics when the program exits.

  • --default-auth=plugin

    The client-side authentication plugin to use. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.10.

  • --disable-log-bin, -D

    Disable binary logging. This is useful for avoiding an endless loop if you use the --to-last-log option and are sending the output to the same MySQL server. This option also is useful when restoring after a crash to avoid duplication of the statements you have logged.

    This option requires that you have the SUPER privilege. It causes mysqlbinlog to include a SET sql_log_bin = 0 statement in its output to disable binary logging of the remaining output. The SET statement is ineffective unless you have the SUPER privilege.

  • --force-read, -f

    With this option, if mysqlbinlog reads a binary log event that it does not recognize, it prints a warning, ignores the event, and continues. Without this option, mysqlbinlog stops if it reads such an event.

  • --hexdump, -H

    Display a hex dump of the log in comments, as described in Section 4.6.7.1, “mysqlbinlog Hex Dump Format”. The hex output can be helpful for replication debugging.

  • --host=host_name, -h host_name

    Get the binary log from the MySQL server on the given host.

  • --local-load=path, -l path

    Prepare local temporary files for LOAD DATA INFILE in the specified directory.

    Important

    These temporary files are not automatically removed by mysqlbinlog or any other MySQL program.

  • --offset=N, -o N

    Skip the first N entries in the log.

  • --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, mysqlbinlog prompts for one.

    Specifying a password on the command line should be considered insecure. See Section 5.3.2.2, “End-User Guidelines for Password Security”. You can use an option file to avoid giving the password on the command line.

  • --plugin-dir=path

    The directory in which to look for plugins. It may be necessary to specify this option if the --default-auth option is used to specify an authentication plugin but mysqlbinlog does not find it. See Section 5.5.6, “Pluggable Authentication”.

    This option was added in MySQL 5.5.10.

  • --port=port_num, -P port_num

    The TCP/IP port number to use for connecting to a remote server.

  • --position=N

    Deprecated. Use --start-position instead. --position was removed in MySQL 5.5.3.

  • --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 permissible values, see Section 4.2.2, “Connecting to the MySQL Server”.

  • --read-from-remote-server, -R

    Read the binary log from a MySQL server rather than reading a local log file. Any connection parameter options are ignored unless this option is given as well. These options are --host, --password, --port, --protocol, --socket, and --user.

    This option requires that the remote server be running. It works only for binary log files on the remote server, not relay log files.

  • --result-file=name, -r name

    Direct output to the given file.

  • --server-id=id

    Display only those events created by the server having the given server ID.

  • --server-id-bits=N

    Use only the first N bits of the server_id to identify the server. If the binary log was written by a mysqld with server-id-bits set to less than 32 and user data stored in the most significant bit, running mysqlbinlog with --server-id-bits set to 32 enables this data to be seen.

    This option is supported only by the versions of mysqlbinlog supplied with the MySQL Cluster distribution, or built from the MySQL Cluster sources.

  • --set-charset=charset_name

    Add a SET NAMES charset_name statement to the output to specify the character set to be used for processing log files.

  • --short-form, -s

    Display only the statements contained in the log, without any extra information or row-based events. This is for testing only, and should not be used in production systems.

  • --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.

  • --start-datetime=datetime

    Start reading the binary log at the first event having a timestamp equal to or later than the datetime argument. The datetime value is relative to the local time zone on the machine where you run mysqlbinlog. The value should be in a format accepted for the DATETIME or TIMESTAMP data types. For example:

    shell> mysqlbinlog --start-datetime="2005-12-25 11:25:56" binlog.000003
    

    This option is useful for point-in-time recovery. See Section 6.3, “Пример Backup and Recovery Strategy”.

  • --start-position=N, -j N

    Start reading the binary log at the first event having a position equal to or greater than N. This option applies to the first log file named on the command line.

    This option is useful for point-in-time recovery. See Section 6.3, “Пример Backup and Recovery Strategy”.

  • --stop-datetime=datetime

    Stop reading the binary log at the first event having a timestamp equal to or later than the datetime argument. This option is useful for point-in-time recovery. See the description of the --start-datetime option for information about the datetime value.

    This option is useful for point-in-time recovery. See Section 6.3, “Пример Backup and Recovery Strategy”.

  • --stop-position=N

    Stop reading the binary log at the first event having a position equal to or greater than N. This option applies to the last log file named on the command line.

    This option is useful for point-in-time recovery. See Section 6.3, “Пример Backup and Recovery Strategy”.

  • --to-last-log, -t

    Do not stop at the end of the requested binary log from a MySQL server, but rather continue printing until the end of the last binary log. If you send the output to the same MySQL server, this may lead to an endless loop. This option requires --read-from-remote-server.

  • --user=user_name, -u user_name

    The MySQL user name to use when connecting to a remote server.

  • --verbose, -v

    Reconstruct row events and display them as commented SQL statements. If this option is given twice, the output includes comments to indicate column data types and some metadata.

    For examples that show the effect of --base64-output and --verbose on row event output, see Section 4.6.7.2, “mysqlbinlog Row Event Display”.

  • --version, -V

    Display version information and exit.

You can also set the following variable by using --var_name=value syntax:

  • open_files_limit

    Specify the number of open file descriptors to reserve.

You can pipe the output of mysqlbinlog into the mysql client to execute the events contained in the binary log. This technique is used to recover from a crash when you have an old backup (see Section 6.5, “Point-in-Time (Incremental) Recovery Using the Binary Log”). For example:

shell> mysqlbinlog binlog.000001 | mysql -u root -p

Or:

shell> mysqlbinlog binlog.[0-9]* | mysql -u root -p

You can also redirect the output of mysqlbinlog to a text file instead, if you need to modify the statement log first (for example, to remove statements that you do not want to execute for some reason). After editing the file, execute the statements that it contains by using it as input to the mysql program:

shell> mysqlbinlog binlog.000001 > tmpfile
shell> ... edit tmpfile ...
shell> mysql -u root -p < tmpfile

When mysqlbinlog is invoked with the --start-position option, it displays only those events with an offset in the binary log greater than or equal to a given position (the given position must match the start of one event). It also has options to stop and start when it sees an event with a given date and time. This enables you to perform point-in-time recovery using the --stop-datetime option (to be able to say, for example, “roll forward my databases to how they were today at 10:30 a.m.”).

If you have more than one binary log to execute on the MySQL server, the safe method is to process them all using a single connection to the server. Here is an example that demonstrates what may be unsafe:

shell> mysqlbinlog binlog.000001 | mysql -u root -p # DANGER!!
shell> mysqlbinlog binlog.000002 | mysql -u root -p # DANGER!!

Processing binary logs this way using multiple connections to the server causes problems if the first log file contains a CREATE TEMPORARY TABLE statement and the second log contains a statement that uses the temporary table. When the first mysql process terminates, the server drops the temporary table. When the second mysql process attempts to use the table, the server reports “unknown table.

To avoid problems like this, use a single mysql process to execute the contents of all binary logs that you want to process. Here is one way to do so:

shell> mysqlbinlog binlog.000001 binlog.000002 | mysql -u root -p

Another approach is to write all the logs to a single file and then process the file:

shell> mysqlbinlog binlog.000001 >  /tmp/statements.sql
shell> mysqlbinlog binlog.000002 >> /tmp/statements.sql
shell> mysql -u root -p -e "source /tmp/statements.sql"

mysqlbinlog can produce output that reproduces a LOAD DATA INFILE operation without the original data file. mysqlbinlog copies the data to a temporary file and writes a LOAD DATA LOCAL INFILE statement that refers to the file. The default location of the directory where these files are written is system-specific. To specify a directory explicitly, use the --local-load option.

Because mysqlbinlog converts LOAD DATA INFILE statements to LOAD DATA LOCAL INFILE statements (that is, it adds LOCAL), both the client and the server that you use to process the statements must be configured with the LOCAL capability enabled. See Section 5.3.5, “Security Issues with LOAD DATA LOCAL.

Warning

The temporary files created for LOAD DATA LOCAL statements are not automatically deleted because they are needed until you actually execute those statements. You should delete the temporary files yourself after you no longer need the statement log. The files can be found in the temporary file directory and have names like original_file_name-#-#.

4.6.7.1. mysqlbinlog Hex Dump Format

The --hexdump option causes mysqlbinlog to produce a hex dump of the binary log contents:

shell> mysqlbinlog --hexdump master-bin.000001

The hex output consists of comment lines beginning with #, so the output might look like this for the preceding command:

/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
# at 4
#051024 17:24:13 server id 1  end_log_pos 98
# Position  Timestamp   Type   Master ID        Size      Master Pos    Flags
# 00000004 9d fc 5c 43   0f   01 00 00 00   5e 00 00 00   62 00 00 00   00 00
# 00000017 04 00 35 2e 30 2e 31 35  2d 64 65 62 75 67 2d 6c |..5.0.15.debug.l|
# 00000027 6f 67 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |og..............|
# 00000037 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |................|
# 00000047 00 00 00 00 9d fc 5c 43  13 38 0d 00 08 00 12 00 |.......C.8......|
# 00000057 04 04 04 04 12 00 00 4b  00 04 1a                |.......K...|
#       Start: binlog v 4, server v 5.0.15-debug-log created 051024 17:24:13
#       at startup
ROLLBACK;

Hex dump output currently contains the elements in the following list. This format is subject to change. (For more information about binary log format, see http://forge.mysql.com/wiki/MySQL_Internals_Binary_Log.)

  • Position: The byte position within the log file.

  • Timestamp: The event timestamp. In the example shown, '9d fc 5c 43' is the representation of '051024 17:24:13' in hexadecimal.

  • Type: The event type code. In the example shown, '0f' indicates a FORMAT_DESCRIPTION_EVENT. The following table lists the possible type codes.

    TypeNameMeaning
    00UNKNOWN_EVENTThis event should never be present in the log.
    01START_EVENT_V3This indicates the start of a log file written by MySQL 4 or earlier.
    02QUERY_EVENTThe most common type of events. These contain statements executed on the master.
    03STOP_EVENTIndicates that master has stopped.
    04ROTATE_EVENTWritten when the master switches to a new log file.
    05INTVAR_EVENTUsed for AUTO_INCREMENT values or when the LAST_INSERT_ID() function is used in the statement.
    06LOAD_EVENTUsed for LOAD DATA INFILE in MySQL 3.23.
    07SLAVE_EVENTReserved for future use.
    08CREATE_FILE_EVENTUsed for LOAD DATA INFILE statements. This indicates the start of execution of such a statement. A temporary file is created on the slave. Used in MySQL 4 only.
    09APPEND_BLOCK_EVENTContains data for use in a LOAD DATA INFILE statement. The data is stored in the temporary file on the slave.
    0aEXEC_LOAD_EVENTUsed for LOAD DATA INFILE statements. The contents of the temporary file is stored in the table on the slave. Used in MySQL 4 only.
    0bDELETE_FILE_EVENTRollback of a LOAD DATA INFILE statement. The temporary file should be deleted on the slave.
    0cNEW_LOAD_EVENTUsed for LOAD DATA INFILE in MySQL 4 and earlier.
    0dRAND_EVENTUsed to send information about random values if the RAND() function is used in the statement.
    0eUSER_VAR_EVENTUsed to replicate user variables.
    0fFORMAT_DESCRIPTION_EVENTThis indicates the start of a log file written by MySQL 5 or later.
    10XID_EVENTEvent indicating commit of an XA transaction.
    11BEGIN_LOAD_QUERY_EVENTUsed for LOAD DATA INFILE statements in MySQL 5 and later.
    12EXECUTE_LOAD_QUERY_EVENTUsed for LOAD DATA INFILE statements in MySQL 5 and later.
    13TABLE_MAP_EVENTInformation about a table definition. Used in MySQL 5.1.5 and later.
    14PRE_GA_WRITE_ROWS_EVENTRow data for a single table that should be created. Used in MySQL 5.1.5 to 5.1.17.
    15PRE_GA_UPDATE_ROWS_EVENTRow data for a single table that needs to be updated. Used in MySQL 5.1.5 to 5.1.17.
    16PRE_GA_DELETE_ROWS_EVENTRow data for a single table that should be deleted. Used in MySQL 5.1.5 to 5.1.17.
    17WRITE_ROWS_EVENTRow data for a single table that should be created. Used in MySQL 5.1.18 and later.
    18UPDATE_ROWS_EVENTRow data for a single table that needs to be updated. Used in MySQL 5.1.18 and later.
    19DELETE_ROWS_EVENTRow data for a single table that should be deleted. Used in MySQL 5.1.18 and later.
    1aINCIDENT_EVENTSomething out of the ordinary happened. Added in MySQL 5.1.18.
  • Master ID: The server ID of the master that created the event.

  • Size: The size in bytes of the event.

  • Master Pos: The position of the next event in the original master log file.

  • Flags: 16 flags. Currently, the following flags are used. The others are reserved for future use.

    FlagNameMeaning
    01LOG_EVENT_BINLOG_IN_USE_FLog file correctly closed. (Used only in FORMAT_DESCRIPTION_EVENT.) If this flag is set (if the flags are, for example, '01 00') in a FORMAT_DESCRIPTION_EVENT, the log file has not been properly closed. Most probably this is because of a master crash (for example, due to power failure).
    02 Reserved for future use.
    04LOG_EVENT_THREAD_SPECIFIC_FSet if the event is dependent on the connection it was executed in (for example, '04 00'), for example, if the event uses temporary tables.
    08LOG_EVENT_SUPPRESS_USE_FSet in some circumstances when the event is not dependent on the default database.

4.6.7.2. mysqlbinlog Row Event Display

The following examples illustrate how mysqlbinlog displays row events that specify data modifications. These correspond to events with the WRITE_ROWS_EVENT, UPDATE_ROWS_EVENT, and DELETE_ROWS_EVENT type codes. The --base64-output=DECODE-ROWS and --verbose options may be used to affect row event output.

Suppose that the server is using row-based binary logging and that you execute the following sequence of statements:

CREATE TABLE t
(
  id   INT NOT NULL,
  name VARCHAR(20) NOT NULL,
  date DATE NULL
) ENGINE = InnoDB;

START TRANSACTION;
INSERT INTO t VALUES(1, 'apple', NULL);
UPDATE t SET name = 'pear', date = '2009-01-01' WHERE id = 1;
DELETE FROM t WHERE id = 1;
COMMIT;

By default, mysqlbinlog displays row events encoded as base-64 strings using BINLOG statements. Omitting extraneous lines, the output for the row events produced by the preceding statement sequence looks like this:

shell> mysqlbinlog log_file
...
# at 218
#080828 15:03:08 server id 1  end_log_pos 258 	Write_rows: table id 17 flags: STMT_END_F

BINLOG '
fAS3SBMBAAAALAAAANoAAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBcBAAAAKAAAAAIBAAAQABEAAAAAAAEAA//8AQAAAAVhcHBsZQ==
'/*!*/;
...
# at 302
#080828 15:03:08 server id 1  end_log_pos 356 	Update_rows: table id 17 flags: STMT_END_F

BINLOG '
fAS3SBMBAAAALAAAAC4BAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBgBAAAANgAAAGQBAAAQABEAAAAAAAEAA////AEAAAAFYXBwbGX4AQAAAARwZWFyIbIP
'/*!*/;
...
# at 400
#080828 15:03:08 server id 1  end_log_pos 442 	Delete_rows: table id 17 flags: STMT_END_F

BINLOG '
fAS3SBMBAAAALAAAAJABAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBkBAAAAKgAAALoBAAAQABEAAAAAAAEAA//4AQAAAARwZWFyIbIP
'/*!*/;

To see the row events as comments in the form of “pseudo-SQL” statements, run mysqlbinlog with the --verbose or -v option. The output will contain lines beginning with ###:

shell> mysqlbinlog -v log_file
...
# at 218
#080828 15:03:08 server id 1  end_log_pos 258 	Write_rows: table id 17 flags: STMT_END_F

BINLOG '
fAS3SBMBAAAALAAAANoAAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBcBAAAAKAAAAAIBAAAQABEAAAAAAAEAA//8AQAAAAVhcHBsZQ==
'/*!*/;
### INSERT INTO test.t
### SET
###   @1=1
###   @2='apple'
###   @3=NULL
...
# at 302
#080828 15:03:08 server id 1  end_log_pos 356 	Update_rows: table id 17 flags: STMT_END_F

BINLOG '
fAS3SBMBAAAALAAAAC4BAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBgBAAAANgAAAGQBAAAQABEAAAAAAAEAA////AEAAAAFYXBwbGX4AQAAAARwZWFyIbIP
'/*!*/;
### UPDATE test.t
### WHERE
###   @1=1
###   @2='apple'
###   @3=NULL
### SET
###   @1=1
###   @2='pear'
###   @3='2009:01:01'
...
# at 400
#080828 15:03:08 server id 1  end_log_pos 442 	Delete_rows: table id 17 flags: STMT_END_F

BINLOG '
fAS3SBMBAAAALAAAAJABAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBkBAAAAKgAAALoBAAAQABEAAAAAAAEAA//4AQAAAARwZWFyIbIP
'/*!*/;
### DELETE FROM test.t
### WHERE
###   @1=1
###   @2='pear'
###   @3='2009:01:01'

Specify --verbose or -v twice to also display data types and some metadata for each column. The output will contain an additional comment following each column change:

shell> mysqlbinlog -vv log_file
...
# at 218
#080828 15:03:08 server id 1  end_log_pos 258 	Write_rows: table id 17 flags: STMT_END_F

BINLOG '
fAS3SBMBAAAALAAAANoAAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBcBAAAAKAAAAAIBAAAQABEAAAAAAAEAA//8AQAAAAVhcHBsZQ==
'/*!*/;
### INSERT INTO test.t
### SET
###   @1=1 /* INT meta=0 nullable=0 is_null=0 */
###   @2='apple' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */
###   @3=NULL /* VARSTRING(20) meta=0 nullable=1 is_null=1 */
...
# at 302
#080828 15:03:08 server id 1  end_log_pos 356 	Update_rows: table id 17 flags: STMT_END_F

BINLOG '
fAS3SBMBAAAALAAAAC4BAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBgBAAAANgAAAGQBAAAQABEAAAAAAAEAA////AEAAAAFYXBwbGX4AQAAAARwZWFyIbIP
'/*!*/;
### UPDATE test.t
### WHERE
###   @1=1 /* INT meta=0 nullable=0 is_null=0 */
###   @2='apple' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */
###   @3=NULL /* VARSTRING(20) meta=0 nullable=1 is_null=1 */
### SET
###   @1=1 /* INT meta=0 nullable=0 is_null=0 */
###   @2='pear' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */
###   @3='2009:01:01' /* DATE meta=0 nullable=1 is_null=0 */
...
# at 400
#080828 15:03:08 server id 1  end_log_pos 442 	Delete_rows: table id 17 flags: STMT_END_F

BINLOG '
fAS3SBMBAAAALAAAAJABAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBkBAAAAKgAAALoBAAAQABEAAAAAAAEAA//4AQAAAARwZWFyIbIP
'/*!*/;
### DELETE FROM test.t
### WHERE
###   @1=1 /* INT meta=0 nullable=0 is_null=0 */
###   @2='pear' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */
###   @3='2009:01:01' /* DATE meta=0 nullable=1 is_null=0 */

You can tell mysqlbinlog to suppress the BINLOG statements for row events by using the --base64-output=DECODE-ROWS option. This is similar to --base64-output=NEVER but does not exit with an error if a row event is found. The combination of --base64-output=DECODE-ROWS and --verbose provides a convenient way to see row events only as SQL statements:

shell> mysqlbinlog -v --base64-output=DECODE-ROWS log_file
...
# at 218
#080828 15:03:08 server id 1  end_log_pos 258 	Write_rows: table id 17 flags: STMT_END_F
### INSERT INTO test.t
### SET
###   @1=1
###   @2='apple'
###   @3=NULL
...
# at 302
#080828 15:03:08 server id 1  end_log_pos 356 	Update_rows: table id 17 flags: STMT_END_F
### UPDATE test.t
### WHERE
###   @1=1
###   @2='apple'
###   @3=NULL
### SET
###   @1=1
###   @2='pear'
###   @3='2009:01:01'
...
# at 400
#080828 15:03:08 server id 1  end_log_pos 442 	Delete_rows: table id 17 flags: STMT_END_F
### DELETE FROM test.t
### WHERE
###   @1=1
###   @2='pear'
###   @3='2009:01:01'
Замечание

You should not suppress BINLOG statements if you intend to re-execute mysqlbinlog output.

The SQL statements produced by --verbose for row events are much more readable than the corresponding BINLOG statements. However, they do not correspond exactly to the original SQL statements that generated the events. The following limitations apply:

  • The original column names are lost and replaced by @N, where N is a column number.

  • Character set information is not available in the binary log, which affects string column display:

    • There is no distinction made between corresponding binary and nonbinary string types (BINARY and CHAR, VARBINARY and VARCHAR, BLOB and TEXT). The output uses a data type of STRING for fixed-length strings and VARSTRING for variable-length strings.

    • For multi-byte character sets, the maximum number of bytes per character is not present in the binary log, so the length for string types is displayed in bytes rather than in characters. For example, STRING(4) will be used as the data type for values from either of these column types:

      CHAR(4) CHARACTER SET latin1
      CHAR(2) CHARACTER SET ucs2
    • Due to the storage format for events of type UPDATE_ROWS_EVENT, UPDATE statements are displayed with the WHERE clause preceding the SET clause.

Proper interpretation of row events requires the information from the format description event at the beginning of the binary log. Because mysqlbinlog does not know in advance whether the rest of the log contains row events, by default it displays the format description event using a BINLOG statement in the initial part of the output.

If the binary log is known not to contain any events requiring a BINLOG statement (that is, no row events), the --base64-output=NEVER option can be used to prevent this header from being written.

4.6.8. mysqldumpslow — Summarize Slow Query Log Files

The MySQL slow query log contains information about queries that take a long time to execute (see Section 5.2.5, “The Slow Query Log”). mysqldumpslow parses MySQL slow query log files and prints a summary of their contents.

Normally, mysqldumpslow groups queries that are similar except for the particular values of number and string data values. It “abstracts” these values to N and 'S' when displaying summary output. The -a and -n options can be used to modify value abstracting behavior.

Invoke mysqldumpslow like this:

shell> mysqldumpslow [options] [log_file ...]

mysqldumpslow supports the following options.

Table 4.12. mysqldumpslow Options

FormatOption FileОписаниеIntroductionDeprecatedRemoved
-a Do not abstract all numbers to N and strings to S   
-n num Abstract numbers with at least the specified digits   
--debugdebugWrite debugging information   
-g pattern Only consider statements that match the pattern   
--help Display help message and exit   
-h name Host name of the server in the log file name   
-i name Name of the server instance   
-l Do not subtract lock time from total time   
-r Reverse the sort order   
-s value How to sort output   
-t num Display only first num queries   
--verboseverboseVerbose mode   
  • --help

    Display a help message and exit.

  • -a

    Do not abstract all numbers to N and strings to 'S'.

  • --debug, -d

    Run in debug mode.

  • -g pattern

    Consider only queries that match the (grep-style) pattern.

  • -h host_name

    Host name of MySQL server for *-slow.log file name. The value can contain a wildcard. The default is * (match all).

  • -i name

    Name of server instance (if using mysql.server startup script).

  • -l

    Do not subtract lock time from total time.

  • -n N

    Abstract numbers with at least N digits within names.

  • -r

    Reverse the sort order.

  • -s sort_type

    How to sort the output. The value of sort_type should be chosen from the following list:

    • t, at: Sort by query time or average query time

    • l, al: Sort by lock time or average lock time

    • r, ar: Sort by rows sent or average rows sent

    • c: Sort by count

    By default, mysqldumpslow sorts by average query time (equivalent to -s at).

  • -t N

    Display only the first N queries in the output.

  • --verbose, -v

    Verbose mode. Print more information about what the program does.

Пример of usage:

shell> mysqldumpslow

Reading mysql slow query log from /usr/local/mysql/data/mysqld51-apple-slow.log
Count: 1  Time=4.32s (4s)  Lock=0.00s (0s)  Rows=0.0 (0), root[root]@localhost
 insert into t2 select * from t1

Count: 3  Time=2.53s (7s)  Lock=0.00s (0s)  Rows=0.0 (0), root[root]@localhost
 insert into t2 select * from t1 limit N

Count: 3  Time=2.13s (6s)  Lock=0.00s (0s)  Rows=0.0 (0), root[root]@localhost
 insert into t1 select * from t1

4.6.9. mysqlhotcopy — A Database Backup Program

mysqlhotcopy is a Perl script that was originally written and contributed by Tim Bunce. It uses FLUSH TABLES, LOCK TABLES, and cp or scp to make a database backup. It is a fast way to make a backup of the database or single tables, but it can be run only on the same machine where the database directories are located. mysqlhotcopy works only for backing up MyISAM and ARCHIVE tables. It runs on Unix.

To use mysqlhotcopy, you must have read access to the files for the tables that you are backing up, the SELECT privilege for those tables, the RELOAD privilege (to be able to execute FLUSH TABLES), and the LOCK TABLES privilege (to be able to lock the tables).

shell> mysqlhotcopy db_name [/path/to/new_directory]
shell> mysqlhotcopy db_name_1 ... db_name_n /path/to/new_directory

Back up tables in the given database that match a regular expression:

shell> mysqlhotcopy db_name./regex/

The regular expression for the table name can be negated by prefixing it with a tilde (“~”):

shell> mysqlhotcopy db_name./~regex/

mysqlhotcopy supports the following options, which can be specified on the command line or in the [mysqlhotcopy] and [client] groups of an option file. For information about option files, see Section 4.2.3.3, “Using Option Files”.

Table 4.13. mysqlhotcopy Options

FormatOption FileОписаниеIntroductionDeprecatedRemoved
--addtodestaddtodestDo not rename target directory (if it exists); merely add files to it   
--allowoldallowoldDo not abort if a target exists; rename it by adding an _old suffix   
--checkpoint=db_name.tbl_namecheckpointInsert checkpoint entries   
--chroot=pathchrootBase directory of the chroot jail in which mysqld operates   
--debugdebugWrite a debugging log   
--dryrundryrunReport actions without performing them   
--flushlogflushlogFlush logs after all tables are locked   
--help Display help message and exit   
--host=host_namehostConnect to the MySQL server on the given host   
--keepoldkeepoldDo not delete previous (renamed) target when done   
--noindicesnoindicesDo not include full index files in the backup   
--old_serverold_serverConnect to server that does not support FLUSH TABLES tbl_list WITH READ LOCK5.5.3  
--password[=password]passwordThe password to use when connecting to the server   
--port=port_numportThe TCP/IP port number to use for the connection   
--quietquietBe silent except for errors   
--regexpregexpCopy all databases with names that match the given regular expression   
--resetmasterresetmasterReset the binary log after locking all the tables   
--resetslaveresetslaveReset the master.info file after locking all the tables   
--socket=pathsocketFor connections to localhost   
--tmpdir=pathtmpdirThe temporary directory   
--user=user_name,userThe MySQL user name to use when connecting to the server   
  • --help, -?

    Display a help message and exit.

  • --addtodest

    Do not rename target directory (if it exists); merely add files to it.

  • --allowold

    Do not abort if a target exists; rename it by adding an _old suffix.

  • --checkpoint=db_name.tbl_name

    Insert checkpoint entries into the specified database db_name and table tbl_name.

  • --chroot=path

    Base directory of the chroot jail in which mysqld operates. The path value should match that of the --chroot option given to mysqld.

  • --debug

    Enable debug output.

  • --dryrun, -n

    Report actions without performing them.

  • --flushlog

    Flush logs after all tables are locked.

  • --host=host_name, -h host_name

    The host name of the local host to use for making a TCP/IP connection to the local server. By default, the connection is made to localhost using a Unix socket file.

  • --keepold

    Do not delete previous (renamed) target when done.

  • --method=command

    The method for copying files (cp or scp). The default is cp.

  • --noindices

    Do not include full index files for MyISAM tables in the backup. This makes the backup smaller and faster. The indexes for reloaded tables can be reconstructed later with myisamchk -rq.

  • --password=password, -ppassword

    The password to use when connecting to the server. The password value is not optional for this option, unlike for other MySQL programs.

    Specifying a password on the command line should be considered insecure. See Section 5.3.2.2, “End-User Guidelines for Password Security”. You can use an option file to avoid giving the password on the command line.

  • --port=port_num, -P port_num

    The TCP/IP port number to use when connecting to the local server.

  • --old_server

    As of MySQL 5.5.3, mysqlhotcopy uses FLUSH TABLES tbl_list WITH READ LOCK to flush and lock tables. Use the --old_server option if the server is older than 5.5.3, which is when that statement was introduced. This option was added in MySQL 5.5.3.

  • --quiet, -q

    Be silent except for errors.

  • --record_log_pos=db_name.tbl_name

    Record master and slave status in the specified database db_name and table tbl_name.

  • --regexp=expr

    Copy all databases with names that match the given regular expression.

  • --resetmaster

    Reset the binary log after locking all the tables.

  • --resetslave

    Reset the master.info file after locking all the tables.

  • --socket=path, -S path<