Chapter 4 MySQL Programs
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Chapter 4 MySQL Programs

Table of Contents

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 NDB Cluster programs. Each program's description indicates its invocation syntax and the options that it supports. Section 23.4, “NDB Cluster Programs”, describes programs specific to NDB Cluster.

Most MySQL distributions include all of these programs, except for those programs that are platform-specific. (For example, the server startup scripts are not used on Windows.) The exception is that RPM distributions are more specialized. There is one RPM for the server, another for client programs, and so forth. If you appear to be missing one or more programs, see Chapter 2, Installing and Upgrading MySQL, for information on types of distributions and what they contain. It may be that you have a distribution that does not include all programs and you need to install an additional package.

Each MySQL program takes many different options. Most programs provide a --help option that you can use to get a description of the program's different options. For example, try mysql --help.

You can override default option values for MySQL programs by specifying options on the command line or in an option file. See Section 4.2, “Using MySQL Programs”, for general information on invoking programs and specifying program options.

The MySQL server, mysqld, is the main program that does most of the work in a MySQL installation. The server is accompanied by several related scripts that assist you in starting and stopping the server:

mysqld
The SQL daemon (that is, the MySQL server). To use client programs, mysqld must be running, because clients gain access to databases by connecting to the server. See Section 4.3.1, “mysqld — The MySQL Server”.
mysqld_safe
A server startup script. mysqld_safe attempts to start mysqld. See Section 4.3.2, “mysqld_safe — MySQL Server Startup Script”.
mysql.server
A server startup script. This script is used on systems that use System V-style run directories containing scripts that start system services for particular run levels. It invokes mysqld_safe to start the MySQL server. See Section 4.3.3, “mysql.server — MySQL Server Startup Script”.
mysqld_multi
A server startup script that can start or stop multiple servers installed on the system. See Section 4.3.4, “mysqld_multi — Manage Multiple MySQL Servers”.

Several programs perform setup operations during MySQL installation or upgrading:

comp_err
This program is used during the MySQL build/installation process. It compiles error message files from the error source files. See Section 4.4.1, “comp_err — Compile MySQL Error Message File”.
mysql_secure_installation
This program enables you to improve the security of your MySQL installation. See Section 4.4.2, “mysql_secure_installation — Improve MySQL Installation Security”.
mysql_ssl_rsa_setup
This program creates the SSL certificate and key files and RSA key-pair files required to support secure connections, if those files are missing. Files created by mysql_ssl_rsa_setup can be used for secure connections using SSL or RSA. See Section 4.4.3, “mysql_ssl_rsa_setup — Create SSL/RSA Files”.
mysql_tzinfo_to_sql
This program loads the time zone tables in the mysql database using the contents of the host system zoneinfo database (the set of files describing time zones). See Section 4.4.4, “mysql_tzinfo_to_sql — Load the Time Zone Tables”.
mysql_upgrade
Prior to MySQL 8.0.16, this program is used after a MySQL upgrade operation. It updates the grant tables with any changes that have been made in newer versions of MySQL, and checks tables for incompatibilities and repairs them if necessary. See Section 4.4.5, “mysql_upgrade — Check and Upgrade MySQL Tables”.
As of MySQL 8.0.16, the MySQL server performs the upgrade tasks previously handled by mysql_upgrade (for details, see Section 2.11.3, “What the MySQL Upgrade Process Upgrades”).

MySQL client programs that connect to the MySQL server:

mysql
The command-line tool for interactively entering SQL statements or executing them from a file in batch mode. See Section 4.5.1, “mysql — The MySQL Command-Line Client”.
mysqladmin
A client that performs administrative operations, such as creating or dropping databases, reloading the grant tables, flushing tables to disk, and reopening log files. mysqladmin can also be used to retrieve version, process, and status information from the server. See Section 4.5.2, “mysqladmin — A MySQL Server Administration Program”.
mysqlcheck
A table-maintenance client that checks, repairs, analyzes, and optimizes tables. See Section 4.5.3, “mysqlcheck — A Table Maintenance Program”.
mysqldump
A client that dumps a MySQL database into a file as SQL, text, or XML. See Section 4.5.4, “mysqldump — A Database Backup Program”.
mysqlimport
A client that imports text files into their respective tables using LOAD DATA. See Section 4.5.5, “mysqlimport — A Data Import Program”.
mysqlpump
A client that dumps a MySQL database into a file as SQL. See Section 4.5.6, “mysqlpump — A Database Backup Program”.
mysqlsh
MySQL Shell is an advanced client and code editor for MySQL Server. See MySQL Shell 8.0 (part of MySQL 8.0). In addition to the provided SQL functionality, similar to mysql, MySQL Shell provides scripting capabilities for JavaScript and Python and includes APIs for working with MySQL. X DevAPI enables you to work with both relational and document data, see Chapter 20, Using MySQL as a Document Store. AdminAPI enables you to work with InnoDB Cluster, see Using MySQL AdminAPI.
mysqlshow
A client that displays information about databases, tables, columns, and indexes. See Section 4.5.7, “mysqlshow — Display Database, Table, and Column Information”.
mysqlslap
A client that is designed to emulate client load for a MySQL server and report the timing of each stage. It works as if multiple clients are accessing the server. See Section 4.5.8, “mysqlslap — A Load Emulation Client”.

MySQL administrative and utility programs:

innochecksum
An offline InnoDB offline file checksum utility. See Section 4.6.2, “innochecksum — Offline InnoDB File Checksum Utility”.
myisam_ftdump
A utility that displays information about full-text indexes in MyISAM tables. See Section 4.6.3, “myisam_ftdump — Display Full-Text Index information”.
myisamchk
A utility to describe, check, optimize, and repair MyISAM tables. See Section 4.6.4, “myisamchk — MyISAM Table-Maintenance Utility”.
myisamlog
A utility that processes the contents of a MyISAM log file. See Section 4.6.5, “myisamlog — Display MyISAM Log File Contents”.
myisampack
A utility that compresses MyISAM tables to produce smaller read-only tables. See Section 4.6.6, “myisampack — Generate Compressed, Read-Only MyISAM Tables”.
mysql_config_editor
A utility that enables you to store authentication credentials in a secure, encrypted login path file named .mylogin.cnf. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
mysqlbinlog
A utility for reading statements from a binary log. The log of executed statements contained in the binary log files can be used to help recover from a crash. See Section 4.6.8, “mysqlbinlog — Utility for Processing Binary Log Files”.
mysqldumpslow
A utility to read and summarize the contents of a slow query log. See Section 4.6.9, “mysqldumpslow — Summarize Slow Query Log Files”.

MySQL program-development utilities:

mysql_config
A shell script that produces the option values needed when compiling MySQL programs. See Section 4.7.1, “mysql_config — Display Options for Compiling Clients”.
my_print_defaults
A utility that shows which options are present in option groups of option files. See Section 4.7.2, “my_print_defaults — Display Options from Option Files”.

Miscellaneous utilities:

lz4_decompress
A utility that decompresses mysqlpump output that was created using LZ4 compression. See Section 4.8.1, “lz4_decompress — Decompress mysqlpump LZ4-Compressed Output”.
perror
A utility that displays the meaning of system or MySQL error codes. See Section 4.8.2, “perror — Display MySQL Error Message Information”.
zlib_decompress
A utility that decompresses mysqlpump output that was created using ZLIB compression. See Section 4.8.3, “zlib_decompress — Decompress mysqlpump ZLIB-Compressed Output”.

Oracle Corporation also provides the MySQL Workbench GUI tool, which is used to administer MySQL servers and databases, to create, execute, and evaluate queries, and to migrate schemas and data from other relational database management systems for use with MySQL.

MySQL client programs that communicate with the server using the MySQL client/server library use the following environment variables.

Environment Variable	Meaning
`MYSQL_UNIX_PORT`	The default Unix socket file; used for connections to `localhost`
`MYSQL_TCP_PORT`	The default port number; used for TCP/IP connections
`MYSQL_DEBUG`	Debug trace options when debugging
`TMPDIR`	The directory where temporary tables and files are created

For a full list of environment variables used by MySQL programs, see Section 4.9, “Environment Variables”.

4.2 Using MySQL Programs

4.2.1 Invoking MySQL Programs
4.2.2 Specifying Program Options
4.2.3 Command Options for Connecting to the Server
4.2.4 Connecting to the MySQL Server Using Command Options
4.2.5 Connecting to the Server Using URI-Like Strings or Key-Value Pairs
4.2.6 Connecting to the Server Using DNS SRV Records
4.2.7 Connection Transport Protocols
4.2.8 Connection Compression Control
4.2.9 Setting Environment Variables

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, ksh, 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 4.2.2, “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 4.2.4, “Connecting to the MySQL Server Using Command Options”.

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 4.2.9, “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 Specifying Program Options

4.2.2.1 Using Options on the Command Line
4.2.2.2 Using Option Files
4.2.2.3 Command-Line Options that Affect Option-File Handling
4.2.2.4 Program Option Modifiers
4.2.2.5 Using Options to Set Program Variables
4.2.2.6 Option Defaults, Options Expecting Values, and the = Sign

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 4.2.9, “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 5.8.3, “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:

mysql -h example.com -h localhost

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.

If conflicting or related options are given, later options take precedence over earlier options. The following command runs mysql in “no column names” mode:

mysql --column-names --skip-column-names

MySQL programs determine which options are given first by examining environment variables, then by processing option files, and then by checking the command line. Because later options take precedence over earlier ones, the processing order means that environment variables have the lowest precedence and command-line options the highest.

For the server, one exception applies: The mysqld-auto.cnf option file in the data directory is processed last, so it takes precedence even over command-line options.

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.

4.2.2.1 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 interactively 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: 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:
```
mysql -ptest
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.)
The MySQL server has certain command options that may be specified only at startup, and a set of system variables, some of which may be set at startup, at runtime, or both. System variable names use underscores rather than dashes, and when referenced at runtime (for example, using SET or SELECT statements), must be written using underscores:
```
SET GLOBAL general_log = ON;
SELECT @@GLOBAL.general_log;
```
At server startup, the syntax for system variables is the same as for command options, so within variable names, dashes and underscores may be used interchangeably. For example, --general_log=ON and --general-log=ON are equivalent. (This is also true for system variables set within option files.)
For options that take a numeric value, the value can be given with a suffix of K, M, or G to indicate a multiplier of 1024, 1024² or 1024³. As of MySQL 8.0.14, a suffix can also be T, P, and E to indicate a multiplier of 1024⁴, 1024⁵ or 1024⁶. Suffix letters can be uppercase or lowercase.
For example, the following command tells mysqladmin to ping the server 1024 times, sleeping 10 seconds between each ping:
```
mysqladmin --count=1K --sleep=10 ping
```
When specifying file names as option values, avoid the use of the ~ shell metacharacter. It might not be interpreted as you expect.

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 one or more semicolon-separated 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:

shell> mysql -u root -p -e "SELECT VERSION();SELECT NOW()"
Enter password: ******
+------------+
| VERSION()  |
+------------+
| 8.0.19     |
+------------+
+---------------------+
| NOW()               |
+---------------------+
| 2019-09-03 10:36:48 |
+---------------------+
shell>

Note

The long form (--execute) is followed by an equal sign (=).

To use quoted values within a statement, you must either 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.

4.2.2.2 Using Option Files

Most MySQL programs can read startup options from option files (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.

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

Note

A MySQL program started with the --no-defaults option reads no option files other than .mylogin.cnf.

A server started with the persisted_globals_load system variable disabled does not read mysqld-auto.cnf.

Many option files are plain text files, created using any text editor. The exceptions are:

The .mylogin.cnf file that contains login path options. This is an encrypted file created by the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”. A “login path” is an option group that permits only certain options: host, user, password, port and socket. Client programs specify which login path to read from .mylogin.cnf using the --login-path option.
To specify an alternative login path file name, set the MYSQL_TEST_LOGIN_FILE environment variable. This variable is used by the mysql-test-run.pl testing utility, but also is recognized by mysql_config_editor and by MySQL clients such as mysql, mysqladmin, and so forth.
The mysqld-auto.cnf file in the data directory. This JSON-format file contains persisted system variable settings. It is created by the server upon execution of SET PERSIST or SET PERSIST_ONLY statements. See Section 5.1.9.3, “Persisted System Variables”. Management of mysqld-auto.cnf should be left to the server and not performed manually.

Option File Processing Order

MySQL looks for option files in the order described in the following discussion and reads any that exist. If an option file you want to use does not exist, create it using the appropriate method, as just discussed.

Note

For information about option files used with NDB Cluster programs, see Section 23.3, “Configuration of NDB Cluster”.

On Windows, MySQL programs read startup options from the files shown in the following table, in the specified order (files listed first are read first, files read later take precedence).

Table 4.1 Option Files Read on Windows Systems

File Name	Purpose
`%WINDIR%\my.ini`, `%WINDIR%\my.cnf`	Global options
`C:\my.ini`, `C:\my.cnf`	Global options
`BASEDIR\my.ini`, `BASEDIR\my.cnf`	Global options
`defaults-extra-file`	The file specified with `--defaults-extra-file`, if any
`%APPDATA%\MySQL\.mylogin.cnf`	Login path options (clients only)
`DATADIR\mysqld-auto.cnf`	System variables persisted with `SET PERSIST` or `SET PERSIST_ONLY` (server only)

In the preceding table, %WINDIR% represents the location of your Windows directory. This is commonly C:\WINDOWS. Use the following command to determine its exact location from the value of the WINDIR environment variable:

C:\> echo %WINDIR%

%APPDATA% represents the value of the Windows application data directory. Use the following command to determine its exact location from the value of the APPDATA environment variable:

C:\> echo %APPDATA%

BASEDIR represents the MySQL base installation directory. When MySQL 8.0 has been installed using MySQL Installer, this is typically C:\PROGRAMDIR\MySQL\MySQL 8.0 Server where PROGRAMDIR represents the programs directory (usually Program Files on English-language versions of Windows), See Section 2.3.3, “MySQL Installer for Windows”.

DATADIR represents the MySQL data directory. As used to find mysqld-auto.cnf, its default value is the data directory location built in when MySQL was compiled, but can be changed by --datadir specified as an option-file or command-line option processed before mysqld-auto.cnf is processed.

On Unix and Unix-like systems, MySQL programs read startup options from the files shown in the following table, in the specified order (files listed first are read first, files read later take precedence).

Note

On Unix platforms, MySQL ignores configuration files that are world-writable. This is intentional as a security measure.

Table 4.2 Option Files Read on Unix and Unix-Like Systems

File Name	Purpose
`/etc/my.cnf`	Global options
`/etc/mysql/my.cnf`	Global options
`SYSCONFDIR/my.cnf`	Global options
`$MYSQL_HOME/my.cnf`	Server-specific options (server only)
`defaults-extra-file`	The file specified with `--defaults-extra-file`, if any
`~/.my.cnf`	User-specific options
`~/.mylogin.cnf`	User-specific login path options (clients only)
`DATADIR/mysqld-auto.cnf`	System variables persisted with `SET PERSIST` or `SE PERSIST_ONLY` (server only)

In the preceding table, ~ 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 sets it to BASEDIR, the MySQL base installation directory.

If multiple instances of a given option are found, the last instance takes precedence, with 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.

Option File Syntax

The following description of option file syntax applies to files that you edit manually. This excludes .mylogin.cnf, which is created using mysql_config_editor and is encrypted, and mysqld-auto.cnf, which the server creates in JSON format.

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. (For mysqld, use --verbose and --help.)

The syntax for specifying options in an option file is similar to command-line syntax (see Section 4.2.2.1, “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. Option group names are not case-sensitive.
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. The value optionally can be enclosed 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. In option files, these escaping rules apply:

A backslash followed by a valid escape sequence character is converted to the character represented by the sequence. For example, \s is converted to a space.
A backslash not followed by a valid escape sequence character 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 valid escape sequence character, \x becomes “x” rather than \x. See Section 9.1.1, “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 is treated as \. Suppose that you want to specify a base directory of C:\Program Files\MySQL\MySQL Server 8.0 in an option file. This can be done several ways. Some examples:

basedir="C:\Program Files\MySQL\MySQL Server 8.0"
basedir="C:\\Program Files\\MySQL\\MySQL Server 8.0"
basedir="C:/Program Files/MySQL/MySQL Server 8.0"
basedir=C:\\Program\sFiles\\MySQL\\MySQL\sServer\s8.0

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 provided in MySQL distributions (but not by mysqld). To understand how third-party client programs that use the C API can use option files, see the C API documentation at mysql_options().

The [client] group enables you to specify options that apply to all clients. For example, [client] is the appropriate group to use to specify the password for connecting to the server. (But make sure that the option file is accessible only by yourself, so that other people cannot discover 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.

List more general option groups first and more specific groups later. For example, a [client] group is more general because it is read by all client programs, whereas a [mysqldump] group is read only by mysqldump. Options specified later override options specified earlier, so putting the option groups in the order [client], [mysqldump] enables mysqldump-specific options to override [client] options.

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=128M

[mysqldump]
quick

Here is a typical user option file:

[client]
# The following password is sent to all standard MySQL clients
password="my password"

[mysql]
no-auto-rehash
connect_timeout=2

To create option groups to be read only by mysqld servers from specific MySQL release series, use groups with names of [mysqld-5.7], [mysqld-8.0], and so forth. The following group indicates that the sql_mode setting should be used only by MySQL servers with 8.0.x version numbers:

[mysqld-8.0]
sql_mode=TRADITIONAL

Option File Inclusions

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

MySQL makes no guarantee about the order in which option files in the directory are read.

Note

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.

If an option file contains !include or !includedir directives, files named by those directives are processed whenever the option file is processed, no matter where they appear in the file.

For inclusion directives to work, the file path should not be specified within quotes and should have no escape sequences. For example, the following statements provided in my.ini read the option file myopts.ini:

!include C:/ProgramData/MySQL/MySQL Server/myopts.ini
!include C:\ProgramData\MySQL\MySQL Server\myopts.ini
!include C:\\ProgramData\\MySQL\\MySQL Server\\myopts.ini

On Windows, if !include /path/to/extra.ini is the last line in the file, make sure that a newline is appended at the end; otherwise, the line is ignored.

4.2.2.3 Command-Line Options that Affect Option-File Handling

Most MySQL programs that support option files handle the following options. Because these options affect option-file handling, they must be given on the command line and not in an option file. To work properly, each of these options must be given before other options, with these exceptions:

--print-defaults may be used immediately after --defaults-file, --defaults-extra-file, or --login-path.
On Windows, if the server is started with the --defaults-file and --install options, --install must be first. See Section 2.3.4.8, “Starting MySQL as a Windows Service”.

When specifying file names as option values, 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 and (on all platforms) before the login path file. (For information about the order in which option files are used, see Section 4.2.2.2, “Using Option Files”.) If the file does not exist or is otherwise inaccessible, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
See the introduction to this section regarding constraints on the position in which this option may be specified.
--defaults-file=file_name
Read only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. file_name is interpreted relative to the current directory if given as a relative path name rather than a full path name.
Exceptions: Even with --defaults-file, mysqld reads mysqld-auto.cnf and client programs read .mylogin.cnf.
See the introduction to this section regarding constraints on the position in which this option may be specified.
--defaults-group-suffix=str
Read not only the 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 this option is given as --defaults-group-suffix=_other, mysql also reads the [client_other] and [mysql_other] groups.
--login-path=name
Read options from the named login path in the .mylogin.cnf login path file. A “login path” is an option group containing options that specify which MySQL server to connect to and which account to authenticate as. To create or modify a login path file, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
A client program reads the option group corresponding to the named login path, in addition to option groups that the program reads by default. Consider this command:
```
mysql --login-path=mypath
```
By default, the mysql client reads the [client] and [mysql] option groups. So for the command shown, mysql reads [client] and [mysql] from other option files, and [client], [mysql], and [mypath] from the login path file.
Client programs read the login path file even when the --no-defaults option is used.
To specify an alternate login path file name, set the MYSQL_TEST_LOGIN_FILE environment variable.
See the introduction to this section regarding constraints on the position in which this option may be specified.
--no-defaults
Do not read any option files. If program startup fails due to reading unknown options from an option file, --no-defaults can be used to prevent them from being read.
The exception is that client programs read the .mylogin.cnf login path file, if it exists, even when --no-defaults is used. This permits passwords to be specified in a safer way than on the command line even if --no-defaults is present. To create .mylogin.cnf, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
--print-defaults
Print the program name and all options that it gets from option files. Password values are masked.
See the introduction to this section regarding constraints on the position in which this option may be specified.

4.2.2.4 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

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 '--loose-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.

The --maximum prefix is available for mysqld only and permits a limit to be placed on how large client programs can set session system variables. To do this, use a --maximum prefix with the variable name. For example, --maximum-max_heap_table_size=32M prevents any client from making the heap table size limit larger than 32M.

The --maximum prefix is intended for use with system variables that have a session value. If applied to a system variable that has only a global value, an error occurs. For example, with --maximum-back_log=200, the server produces this error:

Maximum value of 'back_log' cannot be set

4.2.2.5 Using Options to Set Program Variables

Many MySQL programs have internal variables that can be set at runtime using the SET statement. See Section 13.7.6.1, “SET Syntax for Variable Assignment”, and Section 5.1.9, “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:

mysql --max_allowed_packet=16777216
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 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.) As of MySQL 8.0.14, a suffix can also be T, P, and E to indicate a multiplier of 1024⁴, 1024⁵ or 1024⁶. Suffix letters can be uppercase or lowercase.

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 an option 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

Suffixes for specifying a value multiplier can be used when setting a variable at program invocation time, 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 program invocation time, 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;

4.2.2.6 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:

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:

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: 8.0.25 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
2013-09-24T15:36:22.278034Z 0 [ERROR] Too many arguments (first extra is 'my-errors').
2013-09-24T15:36:22.278059Z 0 [Note] Use --verbose --help to get a list of available options!
2013-09-24T15:36:22.278076Z 0 [ERROR] Aborting
2013-09-24T15:36:22.279704Z 0 [Note] InnoDB: Starting shutdown...
2013-09-24T15:36:23.777471Z 0 [Note] InnoDB: Shutdown completed; log sequence number 2319086
2013-09-24T15:36:23.780134Z 0 [Note] mysqld: Shutdown complete

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: 8.0.25 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 equal 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: 8.0.25 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)

Specifying an option requiring a value without a value in an option file causes the server to abort with an error.

4.2.3 Command Options for Connecting to the Server

This section describes options supported by most MySQL client programs that control how client programs establish connections to the server, whether connections are encrypted, and whether connections are compressed. These options can be given on the command line or in an option file.

Command Options for Connection Establishment

This section describes options that control how client programs establish connections to the server. For additional information and examples showing how to use them, see Section 4.2.4, “Connecting to the MySQL Server Using Command Options”.

Table 4.3 Connection-Establishment Option Summary

Option Name	Description
--default-auth	Authentication plugin to use
--host	Host on which MySQL server is located
--password	Password to use when connecting to server
--pipe	Connect to server using named pipe (Windows only)
--plugin-dir	Directory where plugins are installed
--port	TCP/IP port number for connection
--protocol	Transport protocol to use
--shared-memory-base-name	Shared-memory name for shared-memory connections (Windows only)
--socket	Unix socket file or Windows named pipe to use
--user	MySQL user name to use when connecting to server

--default-auth=plugin
A hint about which client-side authentication plugin to use. See Section 6.2.17, “Pluggable Authentication”.
--host=host_name, -h host_name
The host on which the MySQL server is running. The value can be a host name, IPv4 address, or IPv6 address. The default value is localhost.
--password[=pass_val], -p[pass_val]
The password of the MySQL account used for connecting to the server. The password value is optional. If not given, the program prompts for one. If given, there must be no space between --password= or -p and the password following it. If no password option is specified, the default is to send no password.
Specifying a password on the command line should be considered insecure. To avoid giving the password on the command line, use an option file. See Section 6.1.2.1, “End-User Guidelines for Password Security”.
To explicitly specify that there is no password and that the client program should not prompt for one, use the --skip-password option.
--pipe, -W
On Windows, connect to the server using a named pipe. This option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--plugin-dir=dir_name
The directory in which to look for plugins. Specify this option if the --default-auth option is used to specify an authentication plugin but the client program does not find it. See Section 6.2.17, “Pluggable Authentication”.
--port=port_num, -P port_num
For TCP/IP connections, the port number to use. The default port number is 3306.

--protocol={TCP|SOCKET|PIPE|MEMORY}

This option explicitly specifies which transport protocol to use for connecting to the server. It is useful when other connection parameters normally result in use of a protocol other than the one you want. For example, connections on Unix to localhost are made using a Unix socket file by default:

mysql --host=localhost

To force TCP/IP transport to be used instead, specify a --protocol option:

mysql --host=localhost --protocol=TCP

The following table shows the permissible --protocol option values and indicates the applicable platforms for each value. The values are not case-sensitive.

`--protocol` Value	Transport Protocol Used	Applicable Platforms
`TCP`	TCP/IP transport to local or remote server	All
`SOCKET`	Unix socket-file transport to local server	Unix and Unix-like systems
`PIPE`	Named-pipe transport to local server	Windows
`MEMORY`	Shared-memory transport to local server	Windows

--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.
This option applies only if the server was started with the shared_memory system variable enabled to support shared-memory connections.
--socket=path, -S path
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.
On Windows, this option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--user=user_name, -u user_name
The user name of the MySQL account to use for connecting to the server. The default user name is ODBC on Windows or your Unix login name on Unix.

Command Options for Encrypted Connections

This section describes options for client programs that specify whether to use encrypted connections to the server, the names of certificate and key files, and other parameters related to encrypted-connection support. For examples of suggested use and how to check whether a connection is encrypted, see Section 6.3.1, “Configuring MySQL to Use Encrypted Connections”.

Note

These options have an effect only for connections that use a transport protocol subject to encryption; that is, TCP/IP and Unix socket-file connections. See Section 4.2.7, “Connection Transport Protocols”

For information about using encrypted connections from the MySQL C API, see C API Support for Encrypted Connections.

Table 4.4 Connection-Encryption Option Summary

Option Name	Description	Introduced
--get-server-public-key	Request RSA public key from server
--server-public-key-path	Path name to file containing RSA public key
--ssl-ca	File that contains list of trusted SSL Certificate Authorities
--ssl-capath	Directory that contains trusted SSL Certificate Authority certificate files
--ssl-cert	File that contains X.509 certificate
--ssl-cipher	Permissible ciphers for connection encryption
--ssl-crl	File that contains certificate revocation lists
--ssl-crlpath	Directory that contains certificate revocation-list files
--ssl-fips-mode	Whether to enable FIPS mode on client side
--ssl-key	File that contains X.509 key
--ssl-mode	Desired security state of connection to server
--tls-ciphersuites	Permissible TLSv1.3 ciphersuites for encrypted connections	8.0.16
--tls-version	Permissible TLS protocols for encrypted connections

--get-server-public-key
Request from the server the public key required for RSA key pair-based password exchange. This option applies to clients that authenticate with the caching_sha2_password authentication plugin. For that plugin, the server does not send the public key unless requested. This option is ignored for accounts that do not authenticate with that plugin. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For information about the caching_sha2_password plugin, see Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--server-public-key-path=file_name
The path name to a file in PEM format containing a client-side copy of the public key required by the server for RSA key pair-based password exchange. This option applies to clients that authenticate with the sha256_password or caching_sha2_password authentication plugin. This option is ignored for accounts that do not authenticate with one of those plugins. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
This option is available only if MySQL was built using OpenSSL.
For information about the sha256_password and caching_sha2_password plugins, see Section 6.4.1.3, “SHA-256 Pluggable Authentication”, and Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--ssl-ca=file_name
The path name of the Certificate Authority (CA) certificate file in PEM format. The file contains a list of trusted SSL Certificate Authorities.
To tell the client not to authenticate the server certificate when establishing an encrypted connection to the server, specify neither --ssl-ca nor --ssl-capath. The server still verifies the client according to any applicable requirements established for the client account, and it still uses any ssl_ca or ssl_capath system variable values specified on the server side.
To specify the CA file for the server, set the ssl_ca system variable.
--ssl-capath=dir_name
The path name of the directory that contains trusted SSL certificate authority (CA) certificate files in PEM format.
To tell the client not to authenticate the server certificate when establishing an encrypted connection to the server, specify neither --ssl-ca nor --ssl-capath. The server still verifies the client according to any applicable requirements established for the client account, and it still uses any ssl_ca or ssl_capath system variable values specified on the server side.
To specify the CA directory for the server, set the ssl_capath system variable.
--ssl-cert=file_name
The path name of the client SSL public key certificate file in PEM format.
To specify the server SSL public key certificate file, set the ssl_cert system variable.
--ssl-cipher=cipher_list
The list of permissible encryption ciphers for connections that use TLS protocols up through TLSv1.2. If no cipher in the list is supported, encrypted connections that use these TLS protocols do not work.
For greatest portability, cipher_list should be a list of one or more cipher names, separated by colons. Examples:
```
--ssl-cipher=AES128-SHA
--ssl-cipher=DHE-RSA-AES128-GCM-SHA256:AES128-SHA
```
OpenSSL supports the syntax for specifying ciphers described in the OpenSSL documentation at https://www.openssl.org/docs/manmaster/man1/ciphers.html.
For information about which encryption ciphers MySQL supports, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
To specify the encryption ciphers for the server, set the ssl_cipher system variable.
--ssl-crl=file_name
The path name of the file containing certificate revocation lists in PEM format.
If neither --ssl-crl nor --ssl-crlpath is given, no CRL checks are performed, even if the CA path contains certificate revocation lists.
To specify the revocation-list file for the server, set the ssl_crl system variable.
--ssl-crlpath=dir_name
The path name of the directory that contains certificate revocation-list files in PEM format.
If neither --ssl-crl nor --ssl-crlpath is given, no CRL checks are performed, even if the CA path contains certificate revocation lists.
To specify the revocation-list directory for the server, set the ssl_crlpath system variable.
--ssl-fips-mode={OFF|ON|STRICT}
Controls whether to enable FIPS mode on the client side. The --ssl-fips-mode option differs from other --ssl-xxx options in that it is not used to establish encrypted connections, but rather to affect which cryptographic operations to permit. See Section 6.8, “FIPS Support”.
These --ssl-fips-mode values are permissible:
- OFF: Disable FIPS mode.
- ON: Enable FIPS mode.
- STRICT: Enable “strict” FIPS mode.
Note

If the OpenSSL FIPS Object Module is not available, the only permissible value for --ssl-fips-mode is OFF. In this case, setting --ssl-fips-mode to ON or STRICT causes the client to produce a warning at startup and to operate in non-FIPS mode.

To specify the FIPS mode for the server, set the ssl_fips_mode system variable.
--ssl-key=file_name
The path name of the client SSL private key file in PEM format. For better security, use a certificate with an RSA key size of at least 2048 bits.
If the key file is protected by a passphrase, the client program prompts the user for the passphrase. The password must be given interactively; it cannot be stored in a file. If the passphrase is incorrect, the program continues as if it could not read the key.
To specify the server SSL private key file, set the ssl_key system variable.
--ssl-mode=mode
This option specifies the desired security state of the connection to the server. These mode values are permissible, in order of increasing strictness:
- DISABLED: Establish an unencrypted connection.
- PREFERRED: Establish an encrypted connection if the server supports encrypted connections, falling back to an unencrypted connection if an encrypted connection cannot be established. This is the default if --ssl-mode is not specified.
  Connections over Unix socket files are not encrypted with a mode of PREFERRED. To enforce encryption for Unix socket-file connections, use a mode of REQUIRED or stricter. (However, socket-file transport is secure by default, so encrypting a socket-file connection makes it no more secure and increases CPU load.)
- REQUIRED: Establish an encrypted connection if the server supports encrypted connections. The connection attempt fails if an encrypted connection cannot be established.
- VERIFY_CA: Like REQUIRED, but additionally verify the server Certificate Authority (CA) certificate against the configured CA certificates. The connection attempt fails if no valid matching CA certificates are found.
- VERIFY_IDENTITY: Like VERIFY_CA, but additionally perform host name identity verification by checking the host name the client uses for connecting to the server against the identity in the certificate that the server sends to the client:
  - As of MySQL 8.0.12, if the client uses OpenSSL 1.0.2 or higher, the client checks whether the host name that it uses for connecting matches either the Subject Alternative Name value or the Common Name value in the server certificate. Host name identity verification also works with certificates that specify the Common Name using wildcards.
  - Otherwise, the client checks whether the host name that it uses for connecting matches the Common Name value in the server certificate.
  The connection fails if there is a mismatch. For encrypted connections, this option helps prevent man-in-the-middle attacks.
  
  Note
  
  Host name identity verification with VERIFY_IDENTITY does not work with self-signed certificates that are created automatically by the server or manually using mysql_ssl_rsa_setup (see Section 6.3.3.1, “Creating SSL and RSA Certificates and Keys using MySQL”). Such self-signed certificates do not contain the server name as the Common Name value.
The --ssl-mode option interacts with CA certificate options as follows:
- If --ssl-mode is not explicitly set otherwise, use of --ssl-ca or --ssl-capath implies --ssl-mode=VERIFY_CA.
- For --ssl-mode values of VERIFY_CA or VERIFY_IDENTITY, --ssl-ca or --ssl-capath is also required, to supply a CA certificate that matches the one used by the server.
- An explicit --ssl-mode option with a value other than VERIFY_CA or VERIFY_IDENTITY, together with an explicit --ssl-ca or --ssl-capath option, produces a warning that no verification of the server certificate is performed, despite a CA certificate option being specified.
To require use of encrypted connections by a MySQL account, use CREATE USER to create the account with a REQUIRE SSL clause, or use ALTER USER for an existing account to add a REQUIRE SSL clause. This causes connection attempts by clients that use the account to be rejected unless MySQL supports encrypted connections and an encrypted connection can be established.
The REQUIRE clause permits other encryption-related options, which can be used to enforce security requirements stricter than REQUIRE SSL. For additional details about which command options may or must be specified by clients that connect using accounts configured using the various REQUIRE options, see CREATE USER SSL/TLS Options.
--tls-ciphersuites=ciphersuite_list
This option specifies which ciphersuites the client permits for encrypted connections that use TLSv1.3. The value is a list of zero or more colon-separated ciphersuite names. For example:
```
mysql --tls-ciphersuites="suite1:suite2:suite3"
```
The ciphersuites that can be named for this option depend on the SSL library used to compile MySQL. If this option is not set, the client permits the default set of ciphersuites. If the option is set to the empty string, no ciphersuites are enabled and encrypted connections cannot be established. For more information, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
This option was added in MySQL 8.0.16.
To specify which ciphersuites the server permits, set the tls_ciphersuites system variable.
--tls-version=protocol_list
This option specifies the TLS protocols the client permits for encrypted connections. The value is a list of one or more comma-separated protocol versions. For example:
```
mysql --tls-version="TLSv1.1,TLSv1.2"
```
The protocols that can be named for this option depend on the SSL library used to compile MySQL. Permitted protocols should be chosen such as not to leave “holes” in the list. For example, these values do not have holes:
```
--tls-version="TLSv1,TLSv1.1,TLSv1.2,TLSv1.3"
--tls-version="TLSv1.1,TLSv1.2,TLSv1.3"
--tls-version="TLSv1.2,TLSv1.3"
--tls-version="TLSv1.3"
```
These values do have holes and should not be used:
```
--tls-version="TLSv1,TLSv1.2"
--tls-version="TLSv1.1,TLSv1.3"
```
For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
To specify which TLS protocols the server permits, set the tls_version system variable.

Command Options for Connection Compression

This section describes options that enable client programs to control use of compression for connections to the server. For additional information and examples showing how to use them, see Section 4.2.8, “Connection Compression Control”.

Table 4.5 Connection-Compression Option Summary

Option Name	Description	Introduced	Deprecated
--compress	Compress all information sent between client and server		8.0.18
--compression-algorithms	Permitted compression algorithms for connections to server	8.0.18
--zstd-compression-level	Compression level for connections to server that use zstd compression	8.0.18

--compress, -C
Compress all information sent between the client and the server if possible.
As of MySQL 8.0.18, this option is deprecated. Expect it to be removed in a future version of MySQL. See Configuring Legacy Connection Compression.
--compression-algorithms=value
The permitted compression algorithms for connections to the server. The available algorithms are the same as for the protocol_compression_algorithms system variable. The default value is uncompressed.
This option was added in MySQL 8.0.18.
--zstd-compression-level=level
The compression level to use for connections to the server that use the zstd compression algorithm. The permitted levels are from 1 to 22, with larger values indicating increasing levels of compression. The default zstd compression level is 3. The compression level setting has no effect on connections that do not use zstd compression.
This option was added in MySQL 8.0.18.

4.2.4 Connecting to the MySQL Server Using Command Options

This section describes use of command-line options to specify how to establish connections to the MySQL server, for clients such as mysql or mysqldump. For information on establishing connections using URI-like connection strings or key-value pairs, for clients such as MySQL Shell, see Section 4.2.5, “Connecting to the Server Using URI-Like Strings or Key-Value Pairs”. For additional information if you are unable to connect, see Section 6.2.21, “Troubleshooting Problems Connecting to MySQL”.

For a client program 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 default values 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 explicit connection parameters:

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 because neither --password nor -p is given.
For mysql, the first nonoption argument is taken as the name of the default database. Because there is no such argument, mysql selects no default database.

To specify the host name and user name explicitly, as well as a password, supply appropriate options on the command line. To select a default database, add a database-name argument. Examples:

mysql --host=localhost --user=myname --password=password mydb
mysql -h localhost -u myname -ppassword mydb

For password options, the password value is optional:

If you use a --password or -p option and specify a password value, there must be no space between --password= or -p and the password following it.
If you use --password or -p but do not specify a 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, which might enable other users on your system to see the password line by executing a command such as ps. See Section 6.1.2.1, “End-User Guidelines for Password Security”.
To explicitly specify that there is no password and that the client program should not prompt for one, use the --skip-password option.

As just mentioned, including the password value on the command line is a security risk. To avoid this risk, specify the --password or -p option without any following password value:

mysql --host=localhost --user=myname --password mydb
mysql -h localhost -u myname -p mydb

When the --password or -p option is given with 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 limitation is a property of the system library, not MySQL. Internally, MySQL does not have any limit for the length of the password. To work around the limitation on systems affected by it, specify your password in an option file (see Section 4.2.2.2, “Using Option Files”). Another workaround is to change your MySQL password to a value that has eight or fewer characters, but that has the disadvantage that shorter passwords tend to be less secure.

Client programs determine what type of connection to make as follows:

If the host is not specified or is localhost, a connection to the local host occurs:
- On Windows, the client connects using shared memory, if the server was started with the shared_memory system variable enabled to support shared-memory connections.
- 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: the client connects using a Unix socket file. The --socket option or the MYSQL_UNIX_PORT environment variable may be used to specify the socket name.
On Windows, if host is . (period), or TCP/IP is not enabled and --socket is not specified or the host is empty, the client connects using a named pipe, if the server was started with the named_pipe system variable enabled to support named-pipe connections. If named-pipe connections are not supported or if the user making the connection is not a member of the Windows group specified by the named_pipe_full_access_group system variable, an error occurs.
Otherwise, the connection uses TCP/IP.

The --protocol option enables you to use a particular transport protocol even when other options normally result in use of a different protocol. That is, --protocol specifies the transport protocol explicitly and overrides the preceding rules, even for localhost.

Only connection options that are relevant to the selected transport protocol are used or checked. Other connection options are ignored. For example, with --host=localhost on Unix, the client attempts to connect to the local server using a Unix socket file, even if a --port or -P option is given to specify a TCP/IP 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 (instead of localhost), or the IP address or name of the local server. You can also specify the transport protocol explicitly, even for localhost, by using the --protocol=TCP option. Examples:

mysql --host=127.0.0.1
mysql --protocol=TCP

If the server is configured to accept IPv6 connections, clients can connect to the local server over IPv6 using --host=::1. See Section 5.1.13, “IPv6 Support”.

On Windows, to force a MySQL client to use a named-pipe connection, specify the --pipe or --protocol=PIPE option, or specify . (period) as the host name. If the server was not started with the named_pipe system variable enabled to support named-pipe connections or if the user making the connection is not a member of the Windows group specified by the named_pipe_full_access_group system variable, 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 use TCP/IP. This command connects to the server running on remote.example.com using the default port number (3306):

mysql --host=remote.example.com

To specify a port number explicitly, use the --port or -P option:

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 use a socket file by default, so unless you force a TCP/IP connection as previously described, any option that specifies a port number is ignored.

For this command, the program uses a socket file on Unix and the --port option is ignored:

mysql --port=13306 --host=localhost

To cause the port number to be used, force a TCP/IP connection. For example, invoke the program in either of these ways:

mysql --port=13306 --host=127.0.0.1
mysql --port=13306 --protocol=TCP

For additional information about options that control how client programs establish connections to the server, see Section 4.2.3, “Command Options for Connecting to the Server”.

It is possible to specify connection parameters without entering them on the command line each time you invoke a client program:

Specify the connection parameters in the [client] section of an option file. The relevant section of the file might look like this:
```
[client]
host=host_name
user=user_name
password=password
```
For more information, see Section 4.2.2.2, “Using Option Files”.
Some connection parameters can be specified using environment variables. Examples:
- To specify the host for mysql, use MYSQL_HOST.
- On Windows, to specify the MySQL user name, use USER.
For a list of supported environment variables, see Section 4.9, “Environment Variables”.

4.2.5 Connecting to the Server Using URI-Like Strings or Key-Value Pairs

This section describes use of URI-like connection strings or key-value pairs to specify how to establish connections to the MySQL server, for clients such as MySQL Shell. For information on establishing connections using command-line options, for clients such as mysql or mysqldump, see Section 4.2.4, “Connecting to the MySQL Server Using Command Options”. For additional information if you are unable to connect, see Section 6.2.21, “Troubleshooting Problems Connecting to MySQL”.

Note

The term “URI-like” signifies connection-string syntax that is similar to but not identical to the URI (uniform resource identifier) syntax defined by RFC 3986.

The following MySQL clients support connecting to a MySQL server using a URI-like connection string or key-value pairs:

MySQL Shell
MySQL Connectors which implement X DevAPI

This section documents all valid URI-like string and key-value pair connection parameters, many of which are similar to those specified with command-line options:

Parameters specified with a URI-like string use a syntax such as myuser@example.com:3306/main-schema. For the full syntax, see Connecting Using URI-Like Connection Strings.
Parameters specified with key-value pairs use a syntax such as {user:'myuser', host:'example.com', port:3306, schema:'main-schema'}. For the full syntax, see Connecting Using Key-Value Pairs.

Connection parameters are not case-sensitive. Each parameter, if specified, can be given only once. If a parameter is specified more than once, an error occurs.

This section covers the following topics:

Base Connection Parameters

The following discussion describes the parameters available when specifying a connection to MySQL. These parameters can be provided using either a string that conforms to the base URI-like syntax (see Connecting Using URI-Like Connection Strings), or as key-value pairs (see Connecting Using Key-Value Pairs).

scheme: The transport protocol to use. Use mysqlx for X Protocol connections and mysql for classic MySQL protocol connections. If no protocol is specified, the server attempts to guess the protocol. Connectors that support DNS SRV can use the mysqlx+srv scheme (see Connections Using DNS SRV Records).
user: The MySQL user account to provide for the authentication process.
password: The password to use for the authentication process.

Warning

Specifying an explicit password in the connection specification is insecure and not recommended. Later discussion shows how to cause an interactive prompt for the password to occur.
host: The host on which the server instance is running. The value can be a host name, IPv4 address, or IPv6 address. If no host is specified, the default is localhost.
port: The TCP/IP network port on which the target MySQL server is listening for connections. If no port is specified, the default is 33060 for X Protocol connections and 3306 for classic MySQL protocol connections.
socket: The path to a Unix socket file or the name of a Windows named pipe. Values are local file paths. In URI-like strings, they must be encoded, using either percent encoding or by surrounding the path with parentheses. Parentheses eliminate the need to percent encode characters such as the / directory separator character. For example, to connect as root@localhost using the Unix socket /tmp/mysql.sock, specify the path using percent encoding as root@localhost?socket=%2Ftmp%2Fmysql.sock, or using parentheses as root@localhost?socket=(/tmp/mysql.sock).
schema: The default database for the connection. If no database is specified, the connection has no default database.

The handling of localhost on Unix depends on the type of transport protocol. Connections using classic MySQL protocol handle localhost the same way as other MySQL clients, which means that localhost is assumed to be for socket-based connections. For connections using X Protocol, the behavior of localhost differs in that it is assumed to represent the loopback address, for example, IPv4 address 127.0.0.1.

Additional Connection parameters

You can specify options for the connection, either as attributes in a URI-like string by appending ?attribute=value, or as key-value pairs. The following options are available:

ssl-mode: The desired security state for the connection. The following modes are permissible:
- DISABLED
- PREFERRED
- REQUIRED
- VERIFY_CA
- VERIFY_IDENTITY
For information about these modes, see the --ssl-mode option description in Command Options for Encrypted Connections.
ssl-ca: The path to the X.509 certificate authority file in PEM format.
ssl-capath: The path to the directory that contains the X.509 certificates authority files in PEM format.
ssl-cert: The path to the X.509 certificate file in PEM format.
ssl-cipher: The encryption cipher to use for connections that use TLS protocols up through TLSv1.2.
ssl-crl: The path to the file that contains certificate revocation lists in PEM format.
ssl-crlpath: The path to the directory that contains certificate revocation-list files in PEM format.
ssl-key: The path to the X.509 key file in PEM format.
tls-version: The TLS protocols permitted for classic MySQL protocol encrypted connections. This option is supported by MySQL Shell only. The value of tls-version (singular) is a comma separated list, for example TLSv1.1,TLSv1.2. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”. This option depends on the ssl-mode option not being set to DISABLED.
tls-versions: The permissible TLS protocols for encrypted X Protocol connections. The value of tls-versions (plural) is an array such as [TLSv1.2,TLSv1.3]. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”. This option depends on the ssl-mode option not being set to DISABLED.
tls-ciphersuites: The permitted TLS cipher suites. The value of tls-ciphersuites is a list of IANA cipher suite names as listed at TLS Ciphersuites. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”. This option depends on the ssl-mode option not being set to DISABLED.
auth-method: The authentication method to use for the connection. The default is AUTO, meaning that the server attempts to guess. The following methods are permissible:
- AUTO
- MYSQL41
- SHA256_MEMORY
- FROM_CAPABILITIES
- FALLBACK
- PLAIN
For X Protocol connections, any configured auth-method is overridden to this sequence of authentication methods: MYSQL41, SHA256_MEMORY, PLAIN.
get-server-public-key: Request from the server the public key required for RSA key pair-based password exchange. Use when connecting to MySQL 8.0 servers over classic MySQL protocol with SSL mode DISABLED. You must specify the protocol in this case. For example:
```
mysql://user@localhost:3306?get-server-public-key=true
```
This option applies to clients that authenticate with the caching_sha2_password authentication plugin. For that plugin, the server does not send the public key unless requested. This option is ignored for accounts that do not authenticate with that plugin. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over get-server-public-key.
For information about the caching_sha2_password plugin, see Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
server-public-key-path: The path name to a file in PEM format containing a client-side copy of the public key required by the server for RSA key pair-based password exchange. Use when connecting to MySQL 8.0 servers over classic MySQL protocol with SSL mode DISABLED.
This option applies to clients that authenticate with the sha256_password or caching_sha2_password authentication plugin. This option is ignored for accounts that do not authenticate with one of those plugins. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over get-server-public-key.
For information about the sha256_password and caching_sha2_password plugins, see Section 6.4.1.3, “SHA-256 Pluggable Authentication”, and Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
connect-timeout: An integer value used to configure the number of seconds that clients, such as MySQL Shell, wait until they stop trying to connect to an unresponsive MySQL server.
compression: This option requests or disables compression for the connection. Up to MySQL 8.0.19 it operates for classic MySQL protocol connections only, and from MySQL 8.0.20 it also operates for X Protocol connections.
- Up to MySQL 8.0.19, the values for this option are true (or 1) which enables compression, and the default false (or 0) which disables compression.
- From MySQL 8.0.20, the values for this option are required, which requests compression and fails if the server does not support it; preferred, which requests compression and falls back to an uncompressed connection; and disabled, which requests an uncompressed connection and fails if the server does not permit those. preferred is the default for X Protocol connections, and disabled is the default for classic MySQL protocol connections. For information on X Plugin connection compression control, see Section 20.5.5, “Connection Compression with X Plugin”.
Note that different MySQL clients implement their support for connection compression differently. Consult your client's documentation for details.
compression-algorithms and compression-level: These options are available in MySQL Shell 8.0.20 and later for more control over connection compression. You can specify them to select the compression algorithm used for the connection, and the numeric compression level used with that algorithm. You can also use compression-algorithms in place of compression to request compression for the connection. For information on MySQL Shell's connection compression control, see Using Compressed Connections.
connection-attributes: Controls the key-value pairs that application programs pass to the server at connect time. For general information about connection attributes, see Section 27.12.9, “Performance Schema Connection Attribute Tables”. Clients usually define a default set of attributes, which can be disabled or enabled. For example:
```
mysqlx://user@host?connection-attributes
mysqlx://user@host?connection-attributes=true
mysqlx://user@host?connection-attributes=false
```
The default behavior is to send the default attribute set. Applications can specify attributes to be passed in addition to the default attributes. You specify additional connection attributes as a connection-attributes parameter in a connection string. The connection-attributes parameter value must be empty (the same as specifying true), a Boolean value (true or false to enable or disable the default attribute set), or a list or zero or more key=value specifiers separated by commas (to be sent in addition to the default attribute set). Within a list, a missing key value evaluates as an empty string. Further examples:
```
mysqlx://user@host?connection-attributes=[attr1=val1,attr2,attr3=]
mysqlx://user@host?connection-attributes=[]
```
Application-defined attribute names cannot begin with _ because such names are reserved for internal attributes.

Connecting Using URI-Like Connection Strings

You can specify a connection to MySQL Server using a URI-like string. Such strings can be used with the MySQL Shell with the --uri command option, the MySQL Shell \connect command, and MySQL Connectors which implement X DevAPI.

Note

The term “URI-like” signifies connection-string syntax that is similar to but not identical to the URI (uniform resource identifier) syntax defined by RFC 3986.

A URI-like connection string has the following syntax:

[scheme://][user[:[password]]@]host[:port][/schema][?attribute1=value1&attribute2=value2...

Important

Percent encoding must be used for reserved characters in the elements of the URI-like string. For example, if you specify a string that includes the @ character, the character must be replaced by %40. If you include a zone ID in an IPv6 address, the % character used as the separator must be replaced with %25.

The parameters you can use in a URI-like connection string are described at Base Connection Parameters.

MySQL Shell's shell.parseUri() and shell.unparseUri() methods can be used to deconstruct and assemble a URI-like connection string. Given a URI-like connection string, shell.parseUri() returns a dictionary containing each element found in the string. shell.unparseUri() converts a dictionary of URI components and connection options into a valid URI-like connection string for connecting to MySQL, which can be used in MySQL Shell or by MySQL Connectors which implement X DevAPI.

If no password is specified in the URI-like string, which is recommended, interactive clients prompt for the password. The following examples show how to specify URI-like strings with the user name user_name. In each case, the password is prompted for.

An X Protocol connection to a local server instance listening at port 33065.
```
mysqlx://user_name@localhost:33065
```
A classic MySQL protocol connection to a local server instance listening at port 3333.
```
mysql://user_name@localhost:3333
```

An X Protocol connection to a remote server instance, using a host name, an IPv4 address, and an IPv6 address.

mysqlx://user_name@server.example.com/
mysqlx://user_name@198.51.100.14:123
mysqlx://user_name@[2001:db8:85a3:8d3:1319:8a2e:370:7348]

An X Protocol connection using a socket, with the path provided using either percent encoding or parentheses.
```
mysqlx://user_name@/path%2Fto%2Fsocket.sock
mysqlx://user_name@(/path/to/socket.sock)
```

An optional path can be specified, which represents a database.

# use 'world' as the default database
mysqlx://user_name@198.51.100.1/world

# use 'world_x' as the default database, encoding _ as %5F
mysqlx://user_name@198.51.100.2:33060/world%5Fx

An optional query can be specified, consisting of values each given as a key=value pair or as a single key. To specify multiple values, separate them by , characters. A mix of key=value and key values is permissible. Values can be of type list, with list values ordered by appearance. Strings must be either percent encoded or surrounded by parentheses. The following are equivalent.
```
ssluser@127.0.0.1?ssl-ca=%2Froot%2Fclientcert%2Fca-cert.pem\
&ssl-cert=%2Froot%2Fclientcert%2Fclient-cert.pem\
&ssl-key=%2Froot%2Fclientcert%2Fclient-key

ssluser@127.0.0.1?ssl-ca=(/root/clientcert/ca-cert.pem)\
&ssl-cert=(/root/clientcert/client-cert.pem)\
&ssl-key=(/root/clientcert/client-key)
```

To specify a TLS version and ciphersuite to use for encrypted connections:

mysql://user_name@198.51.100.2:3306/world%5Fx?\
tls-versions=[TLSv1.2,TLSv1.3]&tls-ciphersuites=[TLS_DHE_PSK_WITH_AES_128_\
GCM_SHA256, TLS_CHACHA20_POLY1305_SHA256]

The previous examples assume that connections require a password. With interactive clients, the specified user's password is requested at the login prompt. If the user account has no password (which is insecure and not recommended), or if socket peer-credential authentication is in use (for example, with Unix socket connections), you must explicitly specify in the connection string that no password is being provided and the password prompt is not required. To do this, place a : after the user_name in the string but do not specify a password after it. For example:

mysqlx://user_name:@localhost

Connecting Using Key-Value Pairs

In MySQL Shell and some MySQL Connectors which implement X DevAPI, you can specify a connection to MySQL Server using key-value pairs, supplied in language-natural constructs for the implementation. For example, you can supply connection parameters using key-value pairs as a JSON object in JavaScript, or as a dictionary in Python. Regardless of the way the key-value pairs are supplied, the concept remains the same: the keys as described in this section can be assigned values that are used to specify a connection. You can specify connections using key-value pairs in MySQL Shell's shell.connect() method or InnoDB Cluster's dba.createCluster() method, and with some of the MySQL Connectors which implement X DevAPI.

Generally, key-value pairs are surrounded by { and } characters and the , character is used as a separator between key-value pairs. The : character is used between keys and values, and strings must be delimited (for example, using the ' character). It is not necessary to percent encode strings, unlike URI-like connection strings.

A connection specified as key-value pairs has the following format:

{ key: value, key: value, ...}

The parameters you can use as keys for a connection are described at Base Connection Parameters.

If no password is specified in the key-value pairs, which is recommended, interactive clients prompt for the password. The following examples show how to specify connections using key-value pairs with the user name 'user_name'. In each case, the password is prompted for.

An X Protocol connection to a local server instance listening at port 33065.
```
{user:'user_name', host:'localhost', port:33065}
```
A classic MySQL protocol connection to a local server instance listening at port 3333.
```
{user:'user_name', host:'localhost', port:3333}
```

An X Protocol connection to a remote server instance, using a host name, an IPv4 address, and an IPv6 address.

{user:'user_name', host:'server.example.com'}
{user:'user_name', host:198.51.100.14:123}
{user:'user_name', host:[2001:db8:85a3:8d3:1319:8a2e:370:7348]}

An X Protocol connection using a socket.

{user:'user_name', socket:'/path/to/socket/file'}

An optional schema can be specified, which represents a database.
```
{user:'user_name', host:'localhost', schema:'world'}
```

The previous examples assume that connections require a password. With interactive clients, the specified user's password is requested at the login prompt. If the user account has no password (which is insecure and not recommended), or if socket peer-credential authentication is in use (for example, with Unix socket connections), you must explicitly specify that no password is being provided and the password prompt is not required. To do this, provide an empty string using '' after the password key. For example:

{user:'user_name', password:'', host:'localhost'}

4.2.6 Connecting to the Server Using DNS SRV Records

In the Domain Name System (DNS), a SRV record (service location record) is a type of resource record that enables a client to specify a name that indicates a service, protocol, and domain. A DNS lookup on the name returns a reply containing the names of multiple available servers in the domain that provide the required service. For information about DNS SRV, including how a record defines the preference order of the listed servers, see RFC 2782.

MySQL supports the use of DNS SRV records for connecting to servers. A client that receives a DNS SRV lookup result attempts to connect to the MySQL server on each of the listed hosts in order of preference, based on the priority and weighting assigned to each host by the DNS administrator. A failure to connect occurs only if the client cannot connect to any of the servers.

When multiple MySQL instances, such as a cluster of servers, provide the same service for your applications, DNS SRV records can be used to assist with failover, load balancing, and replication services. It is cumbersome for applications to directly manage the set of candidate servers for connection attempts, and DNS SRV records provide an alternative:

DNS SRV records enable a DNS admininstrator to map a single DNS domain to multiple servers. DNS SRV records also can be updated centrally by administrators when servers are added or removed from the configuration or when their host names are changed.
Central management of DNS SRV records eliminates the need for individual clients to identify each possible host in connection requests, or for connections to be handled by an additional software component. An application can use the DNS SRV record to obtain information about candidate MySQL servers, instead of managing the server information itself.
DNS SRV records can be used in combination with connection pooling, in which case connections to hosts that are no longer in the current list of DNS SRV records are removed from the pool when they become idle.

MySQL supports use of DNS SRV records to connect to servers in these contexts:

Several MySQL Connectors implement DNS SRV support; connector-specific options enable requesting DNS SRV record lookup both for X Protocol connections and for classic MySQL protocol connections. For general information, see Connections Using DNS SRV Records. For details, see the documentation for individual MySQL Connectors.
The C API provides a mysql_real_connect_dns_srv() function that is similar to mysql_real_connect(), except that the argument list does not specify the particular host of the MySQL server to connect to. Instead, it names a DNS SRV record that specifies a group of servers. See mysql_real_connect_dns_srv().
The mysql client has a --dns-srv-name option to indicate a DNS SRV record that specifies a group of servers. See Section 4.5.1, “mysql — The MySQL Command-Line Client”.

A DNS SRV name consists of a service, protocol, and domain, with the service and protocol each prefixed by an underscore:

_service._protocol.domain

The following DNS SRV record identifies multiple candidate servers, such as might be used by clients for establishing X Protocol connections:

Name                      TTL   Class  Priority Weight Port  Target
_mysqlx._tcp.example.com. 86400 IN SRV 0        5      33060 server1.example.com.
_mysqlx._tcp.example.com. 86400 IN SRV 0        10     33060 server2.example.com.
_mysqlx._tcp.example.com. 86400 IN SRV 10       5      33060 server3.example.com.
_mysqlx._tcp.example.com. 86400 IN SRV 20       5      33060 server4.example.com.

Here, mysqlx indicates the X Protocol service and tcp indicates the TCP protocol. A client can request this DNS SRV record using the name _mysqlx._tcp.example.com. The particular syntax for specifying the name in the connection request depends on the type of client. For example, a client might support specifying the name within a URI-like connection string or as a key-value pair.

A DNS SRV record for classic protocol connections might look like this:

Name                     TTL   Class  Priority Weight  Port Target
_mysql._tcp.example.com. 86400 IN SRV 0        5       3306 server1.example.com.
_mysql._tcp.example.com. 86400 IN SRV 0        10      3306 server2.example.com.
_mysql._tcp.example.com. 86400 IN SRV 10       5       3306 server3.example.com.
_mysql._tcp.example.com. 86400 IN SRV 20       5       3306 server4.example.com.

Here, the name mysql designates the classic MySQL protocol service, and the port is 3306 (the default classic MySQL protocol port) rather than 33060 (the default X Protocol port).

When DNS SRV record lookup is used, clients generally must apply these rules for connection requests (there may be client- or connector-specific exceptions):

The request must specify the full DNS SRV record name, with the service and protocol names prefixed by underscores.
The request must not specify multiple host names.
The request must not specify a port number.
Only TCP connections are supported. Unix socket files, Windows named pipes, and shared memory cannot be used.

For more information on using DNS SRV based connections in X DevAPI, see Connections Using DNS SRV Records.

4.2.7 Connection Transport Protocols

For programs that use the MySQL client library (for example, mysql and mysqldump), MySQL supports connections to the server based on several transport protocols: TCP/IP, Unix socket file, named pipe, and shared memory. This section describes how to select these protocols, and how they are similar and different.

Transport Protocol Selection

For a given connection, if the transport protocol is not specified explicitly, it is determined implicitly. For example, connections to localhost result in a socket file connection on Unix and Unix-like systems, and a TCP/IP connection to 127.0.0.1 otherwise. For additional information, see Section 4.2.4, “Connecting to the MySQL Server Using Command Options”.

To specify the protocol explicitly, use the --protocol command option. The following table shows the permissible values for --protocol and indicates the applicable platforms for each value. The values are not case-sensitive.

`--protocol` Value	Transport Protocol Used	Applicable Platforms
`TCP`	TCP/IP	All
`SOCKET`	Unix socket file	Unix and Unix-like systems
`PIPE`	Named pipe	Windows
`MEMORY`	Shared memory	Windows

Transport Support for Local and Remote Connections

TCP/IP transport supports connections to local or remote MySQL servers.

Socket-file, named-pipe, and shared-memory transports support connections only to local MySQL servers. (Named-pipe transport does allow for remote connections, but this capability is not implemented in MySQL.)

Interpretation of localhost

If the transport protocol is not specified explicitly, localhost is interpreted as follows:

On Unix and Unix-like systems, a connection to localhost results in a socket-file connection.
Otherwise, a connection to localhost results in a TCP/IP connection to 127.0.0.1.

If the transport protocol is specified explicitly, localhost is interpreted with respect to that protocol. For example, with --protocol=TCP, a connection to localhost results in a TCP/IP connection to 127.0.0.1 on all platforms.

Encryption and Security Characteristics

TCP/IP and socket-file transports are subject to TLS/SSL encryption, using the options described in Command Options for Encrypted Connections. Named-pipe and shared-memory transports are not subject to TLS/SSL encryption.

A connection is secure by default if made over a transport protocol that is secure by default. Otherwise, for protocols that are subject to TLS/SSL encryption, a connection may be made secure using encryption:

TCP/IP connections are not secure by default, but can be encrypted to make them secure.
Socket-file connections are secure by default. They can also be encrypted, but encrypting a socket-file connection makes it no more secure and increases CPU load.
Named-pipe connections are not secure by default, and are not subject to encryption to make them secure. However, the named_pipe_full_access_group system variable is available to control which MySQL users are permitted to use named-pipe connections.
Shared-memory connections are secure by default.

If the require_secure_transport system variable is enabled, the server permits only connections that use some form of secure transport. Per the preceding remarks, connections that use TCP/IP encrypted using TLS/SSL, a socket file, or shared memory are secure connections. TCP/IP connections not encrypted using TLS/SSL and named-pipe connections are not secure.

Connection Compression

All transport protocols are subject to use of compression on the traffic between the client and server. If both compression and encryption are used for a given connection, compression occurs before encryption. For more information, see Section 4.2.8, “Connection Compression Control”.

4.2.8 Connection Compression Control

Connections to the server can use compression on the traffic between client and server to reduce the number of bytes sent over the connection. By default, connections are uncompressed, but can be compressed if the server and the client agree on a mutually permitted compression algorithm.

Compressed connections originate on the client side but affect CPU load on both the client and server sides because both sides perform compression and decompression operations. Because enabling compression decreases performance, its benefits occur primarily when there is low network bandwidth, network transfer time dominates the cost of compression and decompression operations, and result sets are large.

This section describes the available compression-control configuration parameters and the information sources available for monitoring use of compression. It applies to classic MySQL protocol connections.

Compression control applies to connections to the server by client programs and by servers participating in source/replica replication or Group Replication. Compression control does not apply to connections for FEDERATED tables. In the following discussion, “client connection” is shorthand for a connection to the server originating from any source for which compression is supported, unless context indicates a specific connection type.

Note

X Protocol connections to a MySQL Server instance support compression from MySQL 8.0.19, but compression for X Protocol connections operates independently from the compression for classic MySQL protocol connections described here, and is controlled separately. See Section 20.5.5, “Connection Compression with X Plugin” for information on X Protocol connection compression.

Configuring Connection Compression

As of MySQL 8.0.18, these configuration parameters are available for controlling connection compression:

The protocol_compression_algorithms system variable configures which compression algorithms the server permits for incoming connections.
The --compression-algorithms and --zstd-compression-level command-line options configure permitted compression algorithms and zstd compression level for these client programs: mysql, mysqladmin, mysqlbinlog, mysqlcheck, mysqldump, mysqlimport, mysqlpump, mysqlshow, mysqlslap, and mysqltest, and mysql_upgrade. MySQL Shell also offers these command-line options from its 8.0.20 release.
The MYSQL_OPT_COMPRESSION_ALGORITHMS and MYSQL_OPT_ZSTD_COMPRESSION_LEVEL options for the mysql_options() function configure permitted compression algorithms and zstd compression level for client programs that use the MySQL C API.
The MASTER_COMPRESSION_ALGORITHMS and MASTER_ZSTD_COMPRESSION_LEVEL options for the CHANGE MASTER TO statement configure permitted compression algorithms and zstd compression level for replica servers participating in source/replica replication. From MySQL 8.0.23, use the statement CHANGE REPLICATION SOURCE TO and the options SOURCE_COMPRESSION_ALGORITHMS and SOURCE_ZSTD_COMPRESSION_LEVEL instead.
The group_replication_recovery_compression_algorithm and group_replication_recovery_zstd_compression_level system variables configure permitted compression algorithms and zstd compression level for Group Replication recovery connections when a new member joins a group and connects to a donor.

Configuration parameters that enable specifying compression algorithms are string-valued and take a list of one or more comma-separated compression algorithm names, in any order, chosen from the following items (not case-sensitive):

zlib: Permit connections that use the zlib compression algorithm.
zstd: Permit connections that use the zstd compression algorithm (zstd 1.3).
uncompressed: Permit uncompressed connections.

Note

Because uncompressed is an algorithm name that may or may not be configured, it is possible to configure MySQL not to permit uncompressed connections.

Examples:

To configure which compression algorithms the server permits for incoming connections, set the protocol_compression_algorithms system variable. By default, the server permits all available algorithms. To configure that setting explicitly at startup, use these lines in the server my.cnf file:
```
[mysqld]
protocol_compression_algorithms=zlib,zstd,uncompressed
```
To set and persist the protocol_compression_algorithms system variable to that value at runtime, use this statement:
```
SET PERSIST protocol_compression_algorithms='zlib,zstd,uncompressed';
```
SET PERSIST sets the value for the running MySQL instance. It also saves the value, causing it to carry over to subsequent server restarts. To change the value for the running MySQL instance without having it carry over to subsequent restarts, use the GLOBAL keyword rather than PERSIST. See Section 13.7.6.1, “SET Syntax for Variable Assignment”.
To permit only incoming connections that use zstd compression, configure the server at startup like this:
```
[mysqld]
protocol_compression_algorithms=zstd
```
Or, to make the change at runtime:
```
SET PERSIST protocol_compression_algorithms='zstd';
```
To permit the mysql client to initiate zlib or uncompressed connections, invoke it like this:
```
mysql --compression-algorithms=zlib,uncompressed
```
To configure replicas to connect to the source using zlib or zstd connections, with a compression level of 7 for zstd connections, use a CHANGE REPLICATION SOURCE TO statement (from MySQL 8.0.23) or CHANGE MASTER TO statement (before MySQL 8.0.23):
```
CHANGE REPLICATION SOURCE TO
  SOURCE_COMPRESSION_ALGORITHMS = 'zlib,zstd',
  SOURCE_ZSTD_COMPRESSION_LEVEL = 7;
```
This assumes that the slave_compressed_protocol system variable is disabled, for reasons described in Configuring Legacy Connection Compression.

For successful connection setup, both sides of the connection must agree on a mutually permitted compression algorithm. The algorithm-negotiation process attempts to use zlib, then zstd, then uncompressed. If the two sides can find no common algorithm, the connection attempt fails.

Because both sides must agree on the compression algorithm, and because uncompressed is an algorithm value that is not necessarily permitted, fallback to an uncompressed connection does not necessarily occur. For example, if the server is configured to permit zstd and a client is configured to permit zlib,uncompressed, the client cannot connect at all. In this case, no algorithm is common to both sides, so connection attempts fail.

Configuration parameters that enable specifying the zstd compression level take an integer value from 1 to 22, with larger values indicating increasing levels of compression. The default zstd compression level is 3. The compression level setting has no effect on connections that do not use zstd compression.

A configurable zstd compression level enables choosing between less network traffic and higher CPU load versus more network traffic and lower CPU load. Higher compression levels reduce network congestion but the additional CPU load may reduce server performance.

Configuring Legacy Connection Compression

Prior to MySQL 8.0.18, these configuration parameters are available for controlling connection compression:

Client programs support a --compress command-line option to specify use of compression for the connection to the server.
For programs that use the MySQL C API, enabling the MYSQL_OPT_COMPRESS option for the mysql_options() function specifies use of compression for the connection to the server.
For source/replica replication, enabling the slave_compressed_protocol system variable specifies use of compression for replica connections to the source.

In each case, when use of compression is specified, the connection uses the zlib compression algorithm if both sides permit it, with fallback to an uncompressed connection otherwise.

As of MySQL 8.0.18, the compression parameters just described become legacy parameters, due to the additional compression parameters introduced for more control over connection compression that are described in Configuring Connection Compression. An exception is MySQL Shell, where the --compress command-line option remains current, and can be used to request compression without selecting compression algorithms. For information on MySQL Shell's connection compression control, see Using Compressed Connections.

The legacy compression parameters interact with the newer parameters and their semantics change as follows:

The meaning of the legacy --compress option depends on whether --compression-algorithms is specified:
- When --compression-algorithms is not specified, --compress is equivalent to specifying a client-side algorithm set of zlib,uncompressed.
- When --compression-algorithms is specified, --compress is equivalent to specifying an algorithm set of zlib and the full client-side algorithm set is the union of zlib plus the algorithms specified by --compression-algorithms. For example, with both --compress and --compression-algorithms=zlib,zstd, the permitted-algorithm set is zlib plus zlib,zstd; that is, zlib,zstd. With both --compress and --compression-algorithms=zstd,uncompressed, the permitted-algorithm set is zlib plus zstd,uncompressed; that is, zlib,zstd,uncompressed.
The same type of interaction occurs between the legacy MYSQL_OPT_COMPRESS option and the MYSQL_OPT_COMPRESSION_ALGORITHMS option for the mysql_options() C API function.
If the slave_compressed_protocol system variable is enabled, it takes precedence over MASTER_COMPRESSION_ALGORITHMS and connections to the source use zlib compression if both source and replica permit that algorithm. If slave_compressed_protocol is disabled, the value of MASTER_COMPRESSION_ALGORITHMS applies.

Note

The legacy compression-control parameters are deprecated as of MySQL 8.0.18; expect it to be removed in a future version of MySQL.

Monitoring Connection Compression

The Compression status variable is ON or OFF to indicate whether the current connection uses compression.

The mysql client \status command displays a line that says Protocol: Compressed if compression is enabled for the current connection. If that line is not present, the connection is uncompressed.

As of 8.0.14, the MySQL Shell \status command displays a Compression: line that says Disabled or Enabled to indicate whether the connection is compressed.

As of MySQL 8.0.18, these additional sources of information are available for monitoring connection compression:

To monitor compression in use for client connections, use the Compression_algorithm and Compression_level status variables. For the current connection, their values indicate the compression algorithm and compression level, respectively.
To determine which compression algorithms the server is configured to permit for incoming connections, check the protocol_compression_algorithms system variable.
For source/replica replication connections, the configured compression algorithms and compression level are available from multiple sources:
- The Performance Schema replication_connection_configuration table has COMPRESSION_ALGORITHMS and ZSTD_COMPRESSION_LEVEL columns.
- The mysql.slave_master_info system table has Master_compression_algorithms and Master_zstd_compression_level columns. If the master.info file exists, it contains lines for those values as well.

4.2.9 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 4.9, “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, ksh, 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 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

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 a single multithreaded program that does most of the work in a MySQL installation. It does not spawn additional processes. 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.

Note

Some installation packages contain a debugging version of the server named mysqld-debug. Invoke this version instead of mysqld for debugging support, memory allocation checking, and trace file support (see Section 5.9.1.2, “Creating Trace 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:

mysqld --verbose --help

MySQL Server also has a set of system variables that affect its operation as it runs. System variables can be set at server startup, and many of them can be changed at runtime to effect dynamic server reconfiguration. MySQL Server also has a set of status variables that provide information about its operation. You can monitor these status variables to access runtime performance characteristics.

For a full description of MySQL Server command options, system variables, and status variables, see Section 5.1, “The MySQL Server”. For information about installing MySQL and setting up the initial configuration, see Chapter 2, Installing and Upgrading MySQL.

4.3.2 mysqld_safe — MySQL Server Startup Script

mysqld_safe is the recommended way to start a mysqld server on Unix. mysqld_safe adds some safety features such as restarting the server when an error occurs and logging runtime information to an error log. A description of error logging is given later in this section.

Note

For some Linux platforms, MySQL installation from RPM or Debian packages includes systemd support for managing MySQL server startup and shutdown. On these platforms, mysqld_safe is not installed because it is unnecessary. For more information, see Section 2.5.9, “Managing MySQL Server with systemd”.

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 5.1.7, “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 4.2.2.2, “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 finds and uses the --log-error option:

[mysqld]
log-error=error.log

For backward compatibility, mysqld_safe also reads [safe_mysqld] sections, but to be current you should rename such sections to [mysqld_safe].

mysqld_safe accepts options on the command line and in option files, as described in the following table. For information about option files used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.

Table 4.6 mysqld_safe Options

Option Name	Description
--basedir	Path to MySQL installation directory
--core-file-size	Size of core file that mysqld should be able to create
--datadir	Path to data directory
--defaults-extra-file	Read named option file in addition to usual option files
--defaults-file	Read only named option file
--help	Display help message and exit
--ledir	Path to directory where server is located
--log-error	Write error log to named file
--malloc-lib	Alternative malloc library to use for mysqld
--mysqld	Name of server program to start (in ledir directory)
--mysqld-safe-log-timestamps	Timestamp format for logging
--mysqld-version	Suffix for server program name
--nice	Use nice program to set server scheduling priority
--no-defaults	Read no option files
--open-files-limit	Number of files that mysqld should be able to open
--pid-file	Path name of server process ID file
--plugin-dir	Directory where plugins are installed
--port	Port number on which to listen for TCP/IP connections
--skip-kill-mysqld	Do not try to kill stray mysqld processes
--skip-syslog	Do not write error messages to syslog; use error log file
--socket	Socket file on which to listen for Unix socket connections
--syslog	Write error messages to syslog
--syslog-tag	Tag suffix for messages written to syslog
--timezone	Set TZ time zone environment variable to named value
--user	Run mysqld as user having name user_name or numeric user ID user_id

--help
Display a help message and exit.
--basedir=dir_name
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.

Note

The innodb_buffer_pool_in_core_file variable can be used to reduce the size of core files on operating systems that support it. For more information, see Section 15.8.3.7, “Excluding Buffer Pool Pages from Core Files”.
--datadir=dir_name
The path to the data directory.
--defaults-extra-file=file_name
Read this option file in addition to the usual option files. If the file does not exist or is otherwise inaccessible, the server exits with an error. If file_name is not an absolute path name, it is interpreted relative to the current directory. This must be the first option on the command line if it is used.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-file=file_name
Use only the given option file. If the file does not exist or is otherwise inaccessible, the server exits with an error. If file_name is not an absolute path name, it is interpreted relative to the current directory. This must be the first option on the command line if it is used.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--ledir=dir_name
If mysqld_safe cannot find the server, use this option to indicate the path name to the directory where the server is located.
This option is accepted only on the command line, not in option files. On platforms that use systemd, the value can be specified in the value of MYSQLD_OPTS. See Section 2.5.9, “Managing MySQL Server with systemd”.
--log-error=file_name
Write the error log to the given file. See Section 5.4.2, “The Error Log”.
--mysqld-safe-log-timestamps
This option controls the format for timestamps in log output produced by mysqld_safe. The following list describes the permitted values. For any other value, mysqld_safe logs a warning and uses UTC format.
- UTC, utc
  ISO 8601 UTC format (same as --log_timestamps=UTC for the server). This is the default.
- SYSTEM, system
  ISO 8601 local time format (same as --log_timestamps=SYSTEM for the server).
- HYPHEN, hyphen
  YY-MM-DD h:mm:ss format, as in mysqld_safe for MySQL 5.6.
- LEGACY, legacy
  YYMMDD hh:mm:ss format, as in mysqld_safe prior to MySQL 5.6.
--malloc-lib=[lib_name]
The name of the library to use for memory allocation instead of the system malloc() library. The option value must be one of the directories /usr/lib, /usr/lib64, /usr/lib/i386-linux-gnu, or /usr/lib/x86_64-linux-gnu.
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.
- Prior to MySQL 8.0.21, if the option is given as --malloc-lib=tcmalloc, mysqld_safe looks for a tcmalloc library in /usr/lib. 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.
  As of MySQL 8.0.21, tcmalloc is not a permitted value for the --malloc-lib option.
- 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.
Note

On systems that manage the server using systemd, mysqld_safe is not available. Instead, specify the allocation library by setting LD_PRELOAD in /etc/sysconfig/mysql.

Linux users can use the libtcmalloc_minimal.so library on any platform for which a tcmalloc package is installed in /usr/lib by adding these lines to the my.cnf file:
```
[mysqld_safe]
malloc-lib=tcmalloc
```
To use a specific tcmalloc library, specify its full path name. Example:
```
[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.
This option is accepted only on the command line, not in option files. On platforms that use systemd, the value can be specified in the value of MYSQLD_OPTS. See Section 2.5.9, “Managing MySQL Server with systemd”.
--mysqld-version=suffix
This option is similar to the --mysqld option, but you specify only the suffix for the server program name. The base name 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.
This option is accepted only on the command line, not in option files. On platforms that use systemd, the value can be specified in the value of MYSQLD_OPTS. See Section 2.5.9, “Managing MySQL Server with systemd”.
--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. If program startup fails due to reading unknown options from an option file, --no-defaults can be used to prevent them from being read. This must be the first option on the command line if it is used.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--open-files-limit=count
The number of files that mysqld should be able to open. The option value is passed to ulimit -n.

Note

You must start mysqld_safe as root for this to function properly.
--pid-file=file_name
The path name that mysqld should use for its process ID file.
--plugin-dir=dir_name
The path name of the plugin directory.
--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 operating 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.
When syslog is used for error logging, the daemon.err facility/severity is used for all log messages.
Using these options to control mysqld logging is deprecated. To write error log output to the system log, use the instructions at Section 5.4.2.8, “Error Logging to the System Log”. To control the facility, use the server log_syslog_facility system variable.
--syslog-tag=tag
For logging to syslog, messages from mysqld_safe and mysqld are written with identifiers of mysqld_safe and mysqld, respectively. To specify a suffix for the identifiers, use --syslog-tag=tag, which modifies the identifiers to be mysqld_safe-tag and mysqld-tag.
Using this option to control mysqld logging is deprecated. Use the server log_syslog_tag system variable instead. See Section 5.4.2.8, “Error Logging to the System Log”.
--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 is not used. For example, this command does 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:

cd mysql_installation_directory
bin/mysqld_safe &

If mysqld_safe fails, even when invoked from the MySQL installation directory, specify the --ledir and --datadir options to indicate the directories in which the server and databases are located on your system.

mysqld_safe tries to use the sleep and date system utilities to determine how many times per second it has attempted to start. If these utilities are present and the attempted starts per second is greater than 5, mysqld_safe waits 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:

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

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

When mysqld_safe writes a message, notices go to the logging destination (syslog or the error log file) and stdout. Errors go to the logging destination and stderr.

Note

Controlling mysqld logging from mysqld_safe is deprecated. Use the server's native syslog support instead. For more information, see Section 5.4.2.8, “Error Logging to the System Log”.

4.3.3 mysql.server — MySQL Server Startup Script

MySQL distributions on Unix and Unix-like system include a script named mysql.server, which starts the MySQL server using mysqld_safe. 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 macOS Startup Item for MySQL.

mysql.server is the script name as used within the MySQL source tree. The installed name might be different (for example, mysqld or mysql). In the following discussion, adjust the name mysql.server as appropriate for your system.

Note

For some Linux platforms, MySQL installation from RPM or Debian packages includes systemd support for managing MySQL server startup and shutdown. On these platforms, mysql.server and mysqld_safe are not installed because they are unnecessary. For more information, see Section 2.5.9, “Managing MySQL Server with systemd”.

To start or stop the server manually using the mysql.server script, invoke it from the command line with start or stop arguments:

mysql.server start
mysql.server stop

mysql.server changes location to the MySQL installation directory, then invokes mysqld_safe. To run the server as some specific user, add an appropriate user option to the [mysqld] group of the global /etc/my.cnf option file, as shown later in this section. (It is possible that you must edit mysql.server if you've installed a binary distribution of MySQL in a nonstandard location. Modify it to change location into the proper directory before it runs mysqld_safe. If you do this, your modified version of mysql.server may be overwritten if you upgrade MySQL in the future; make a copy of your edited version that you can reinstall.)

mysql.server stop stops the server by sending a signal to it. You can also stop the server manually by executing mysqladmin shutdown.

To start and stop MySQL automatically on your server, you must add start and stop commands to the appropriate places in your /etc/rc* files:

If you use the Linux server RPM package (MySQL-server-VERSION.rpm), or a native Linux package installation, the mysql.server script may be installed in the /etc/init.d directory with the name mysqld or mysql. See Section 2.5.4, “Installing MySQL on Linux Using RPM Packages from Oracle”, for more information on the Linux RPM packages.
If you install MySQL from a source distribution or using a binary distribution format that does not install mysql.server automatically, you can install the script manually. It can be found in the support-files directory under the MySQL installation directory or in a MySQL source tree. Copy the script to the /etc/init.d directory with the name mysql and make it executable:
```
cp mysql.server /etc/init.d/mysql
chmod +x /etc/init.d/mysql
```
After installing the script, the commands needed to activate it to run at system startup depend on your operating system. On Linux, you can use chkconfig:
```
chkconfig --add mysql
```
On some Linux systems, the following command also seems to be necessary to fully enable the mysql script:
```
chkconfig --level 345 mysql on
```
On FreeBSD, startup scripts generally should go in /usr/local/etc/rc.d/. Install the mysql.server script as /usr/local/etc/rc.d/mysql.server.sh to enable automatic startup. The rc(8) manual page states that scripts in this directory are executed only if their base name matches the *.sh shell file name pattern. Any other files or directories present within the directory are silently ignored.
As an alternative to the preceding setup, some operating systems also use /etc/rc.local or /etc/init.d/boot.local to start additional services on startup. To start up MySQL using this method, append a command like the one following to the appropriate startup file:
```
/bin/sh -c 'cd /usr/local/mysql; ./bin/mysqld_safe --user=mysql &'
```
For other systems, consult your operating system documentation to see how to install startup scripts.

mysql.server reads options from the [mysql.server] and [mysqld] sections of option files. For backward compatibility, it also reads [mysql_server] sections, but to be current you should rename such sections to [mysql.server].

You can add options for mysql.server in a global /etc/my.cnf file. A typical my.cnf file might look like this:

[mysqld]
datadir=/usr/local/mysql/var
socket=/var/tmp/mysql.sock
port=3306
user=mysql

[mysql.server]
basedir=/usr/local/mysql

The mysql.server script supports the options shown in the following table. If specified, they must be placed in an option file, not on the command line. mysql.server supports only start and stop as command-line arguments.

Table 4.7 mysql.server Option-File Options

Option Name	Description	Type
`basedir`	Path to MySQL installation directory	Directory name
`datadir`	Path to MySQL data directory	Directory name
`pid-file`	File in which server should write its process ID	File name
`service-startup-timeout`	How long to wait for server startup	Integer

basedir=dir_name
The path to the MySQL installation directory.
datadir=dir_name
The path to the MySQL data directory.
pid-file=file_name
The path name of the file in which the server should write its process ID. The server creates the file in the data directory unless an absolute path name is given to specify a different directory.
If this option is not given, mysql.server uses a default value of host_name.pid. The PID file value passed to mysqld_safe overrides any value specified in the [mysqld_safe] option file group. Because mysql.server reads the [mysqld] option file group but not the [mysqld_safe] group, you can ensure that mysqld_safe gets the same value when invoked from mysql.server as when invoked manually by putting the same pid-file setting in both the [mysqld_safe] and [mysqld] groups.
service-startup-timeout=seconds
How long in seconds to wait for confirmation of server startup. If the server does not start within this time, mysql.server exits with an error. The default value is 900. A value of 0 means not to wait at all for startup. Negative values mean to wait forever (no timeout).

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.

Note

For some Linux platforms, MySQL installation from RPM or Debian packages includes systemd support for managing MySQL server startup and shutdown. On these platforms, mysqld_multi is not installed because it is unnecessary. For information about using systemd to handle multiple MySQL instances, see Section 2.5.9, “Managing MySQL Server with systemd”.

mysqld_multi searches for groups named [mysqldN] in my.cnf (or in the file named by the --defaults-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 2.10.5, “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 5.8, “Running Multiple MySQL Instances on One Machine”.

To invoke mysqld_multi, use the following syntax:

mysqld_multi [options] {start|stop|reload|report} [GNR[,GNR] ...]

start, stop, reload (stop and restart), 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]:

mysqld_multi start 17

This command stops several servers, using option groups [mysqld8] and [mysqld10] through [mysqld13]:

mysqld_multi stop 8,10-13

For an example of how you might set up an option file, use this command:

mysqld_multi --example

mysqld_multi searches for option files as follows:

With --no-defaults, no option files are read.
With --defaults-file=file_name, only the named file is read.
Otherwise, option files in the standard list of locations are read, including any file named by the --defaults-extra-file=file_name option, if one is given. (If the option is given multiple times, the last value is used.)

For additional information about these and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.

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 are used for that instance.

mysqld_multi supports the following options.

--help
Display a help message and exit.
--example
Display a sample option file.
--log=file_name
Specify the name of the log file. If the file exists, log output is appended to it.
--mysqladmin=prog_name
The mysqladmin binary to be used to stop servers.
--mysqld=prog_name
The mysqld binary to be used. Note that you can specify mysqld_safe as the value for this option also. If you use mysqld_safe to start the server, you can include the mysqld or ledir options in the corresponding [mysqldN] option group. These options indicate the name of the server that mysqld_safe should start and the path name of the directory where the server is located. (See the descriptions for these options in Section 4.3.2, “mysqld_safe — MySQL Server Startup Script”.) Example:
```
[mysqld38]
mysqld = mysqld-debug
ledir  = /opt/local/mysql/libexec
```
--no-log
Print log information to stdout rather than to the log file. By default, output goes to the log file.
--password=password
The password of the MySQL account to use when invoking mysqladmin. Note that the password value is not optional for this option, unlike for other MySQL programs.
--silent
Silent mode; disable warnings.
--tcp-ip
Connect to each MySQL server 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 5.8, “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 6.1.5, “How to Run MySQL as a Normal User”.
Make sure that the MySQL account used for stopping the mysqld servers (with the mysqladmin program) has the same user name and password for each server. Also, make sure that the account has the SHUTDOWN privilege. If the servers that you want to manage have different user names or passwords for the administrative accounts, you might want to create an account on each server that has the same user name and password. For example, you might set up a common multi_admin account by executing the following commands for each server:
```
shell> mysql -u root -S /tmp/mysql.sock -p
Enter password:
mysql> CREATE USER 'multi_admin'@'localhost' IDENTIFIED BY 'multipass';
mysql> GRANT SHUTDOWN ON *.* TO 'multi_admin'@'localhost';
```
See Section 6.2, “Access Control and Account Management”. 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 set the bind_address system variable 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.
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 is an example of a my.cnf file for mysqld_multi.
# Usually this file is located in home dir ~/.my.cnf or /etc/my.cnf

[mysqld_multi]
mysqld     = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
user       = multi_admin
password   = my_password

[mysqld2]
socket     = /tmp/mysql.sock2
port       = 3307
pid-file   = /usr/local/mysql/data2/hostname.pid2
datadir    = /usr/local/mysql/data2
language   = /usr/local/mysql/share/mysql/english
user       = unix_user1

[mysqld3]
mysqld     = /path/to/mysqld_safe
ledir      = /path/to/mysqld-binary/
mysqladmin = /path/to/mysqladmin
socket     = /tmp/mysql.sock3
port       = 3308
pid-file   = /usr/local/mysql/data3/hostname.pid3
datadir    = /usr/local/mysql/data3
language   = /usr/local/mysql/share/mysql/swedish
user       = unix_user2

[mysqld4]
socket     = /tmp/mysql.sock4
port       = 3309
pid-file   = /usr/local/mysql/data4/hostname.pid4
datadir    = /usr/local/mysql/data4
language   = /usr/local/mysql/share/mysql/estonia
user       = unix_user3

[mysqld6]
socket     = /tmp/mysql.sock6
port       = 3311
pid-file   = /usr/local/mysql/data6/hostname.pid6
datadir    = /usr/local/mysql/data6
language   = /usr/local/mysql/share/mysql/japanese
user       = unix_user4

See Section 4.2.2.2, “Using Option Files”.

4.4 Installation-Related Programs

4.4.1 comp_err — Compile MySQL Error Message File
4.4.2 mysql_secure_installation — Improve MySQL Installation Security
4.4.3 mysql_ssl_rsa_setup — Create SSL/RSA Files
4.4.4 mysql_tzinfo_to_sql — Load the Time Zone Tables
4.4.5 mysql_upgrade — Check and Upgrade MySQL Tables

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 text-format error information in MySQL source distributions:

As of MySQL 8.0.19, the error information comes from the messages_to_error_log.txt and messages_to_clients.txt files in the share directory.
For more information about defining error messages, see the comments within those files, along with the errmsg_readme.txt file.
Prior to MySQL 8.0.19, the error information comes from the errmsg-utf8.txt file in the sql/share directory.

comp_err also generates the mysqld_error.h, mysqld_ername.h, and mysqld_errmsg.h header files.

Invoke comp_err like this:

comp_err [options]

comp_err supports the following options.

--help, -?
Display a help message and exit.
--charset=dir_name, -C dir_name
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.
--errmsg-file=file_name, -H file_name
The name of the error message file. The default is mysqld_errmsg.h. This option was added in MySQL 8.0.18.
--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 ../share/errmsg-utf8.txt.
This option was removed in MySQL 8.0.19 and replaced by the --in-file-errlog and --in-file-toclient options.
--in-file-errlog=file_name, -e file_name
The name of the input file that defines error messages intended to be written to the error log. The default is ../share/messages_to_error_log.txt.
This option was added in MySQL 8.0.19.
--in-file-toclient=file_name, -c file_name
The name of the input file that defines error messages intended to be written to clients. The default is ../share/messages_to_clients.txt.
This option was added in MySQL 8.0.19.
--name-file=file_name, -N file_name
The name of the error name file. The default is mysqld_ername.h.
--out-dir=dir_name, -D dir_name
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.
--version, -V
Display version information and exit.

4.4.2 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 2.10.4, “Securing the Initial MySQL Account”.

Normal usage is to connect to the local MySQL server; invoke mysql_secure_installation without arguments:

mysql_secure_installation

When executed, mysql_secure_installation prompts you to determine which actions to perform.

The validate_password component can be used for password strength checking. If the plugin is not installed, mysql_secure_installation prompts the user whether to install it. Any passwords entered later are checked using the plugin if it is enabled.

Most of the usual MySQL client options such as --host and --port can be used on the command line and in option files. For example, to connect to the local server over IPv6 using port 3307, use this command:

mysql_secure_installation --host=::1 --port=3307

mysql_secure_installation supports the following options, which can be specified on the command line or in the [mysql_secure_installation] and [client] groups of an option file. For information about option files used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.

Table 4.8 mysql_secure_installation Options

Option Name	Description	Introduced
--defaults-extra-file	Read named option file in addition to usual option files
--defaults-file	Read only named option file
--defaults-group-suffix	Option group suffix value
--help	Display help message and exit
--host	Host on which MySQL server is located
--no-defaults	Read no option files
--password	Accepted but always ignored. Whenever mysql_secure_installation is invoked, the user is prompted for a password, regardless
--port	TCP/IP port number for connection
--print-defaults	Print default options
--protocol	Transport protocol to use
--socket	Unix socket file or Windows named pipe to use
--ssl-ca	File that contains list of trusted SSL Certificate Authorities
--ssl-capath	Directory that contains trusted SSL Certificate Authority certificate files
--ssl-cert	File that contains X.509 certificate
--ssl-cipher	Permissible ciphers for connection encryption
--ssl-crl	File that contains certificate revocation lists
--ssl-crlpath	Directory that contains certificate revocation-list files
--ssl-fips-mode	Whether to enable FIPS mode on client side
--ssl-key	File that contains X.509 key
--tls-ciphersuites	Permissible TLSv1.3 ciphersuites for encrypted connections	8.0.16
--tls-version	Permissible TLS protocols for encrypted connections
--use-default	Execute with no user interactivity
--user	MySQL user name to use when connecting to server

--help, -?
Display a help message and exit.
--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, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-file=file_name
Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-group-suffix=str
Read not only the usual option groups, but also groups with the usual names and a suffix of str. For example, mysql_secure_installation normally reads the [client] and [mysql_secure_installation] groups. If this option is given as --defaults-group-suffix=_other, mysql_secure_installation also reads the [client_other] and [mysql_secure_installation_other] groups.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--host=host_name, -h host_name
Connect to the MySQL server on the given host.
--no-defaults
Do not read any option files. If program startup fails due to reading unknown options from an option file, --no-defaults can be used to prevent them from being read.
The exception is that the .mylogin.cnf file is read in all cases, if it exists. This permits passwords to be specified in a safer way than on the command line even when --no-defaults is used. To create .mylogin.cnf, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--password=password, -p password
This option is accepted but ignored. Whether or not this option is used, mysql_secure_installation always prompts the user for a password.
--port=port_num, -P port_num
For TCP/IP connections, the port number to use.
--print-defaults
Print the program name and all options that it gets from option files.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The transport protocol to use for connecting to the server. It is useful when the other connection parameters normally result in use of a protocol other than the one you want. For details on the permissible values, see Section 4.2.7, “Connection Transport Protocols”.
--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.
On Windows, this option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--ssl*
Options that begin with --ssl specify whether to connect to the server using encryption and indicate where to find SSL keys and certificates. See Command Options for Encrypted Connections.
--ssl-fips-mode={OFF|ON|STRICT}
Controls whether to enable FIPS mode on the client side. The --ssl-fips-mode option differs from other --ssl-xxx options in that it is not used to establish encrypted connections, but rather to affect which cryptographic operations to permit. See Section 6.8, “FIPS Support”.
These --ssl-fips-mode values are permitted:
- OFF: Disable FIPS mode.
- ON: Enable FIPS mode.
- STRICT: Enable “strict” FIPS mode.
Note

If the OpenSSL FIPS Object Module is not available, the only permitted value for --ssl-fips-mode is OFF. In this case, setting --ssl-fips-mode to ON or STRICT causes the client to produce a warning at startup and to operate in non-FIPS mode.
--tls-ciphersuites=ciphersuite_list
The permissible ciphersuites for encrypted connections that use TLSv1.3. The value is a list of one or more colon-separated ciphersuite names. The ciphersuites that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
This option was added in MySQL 8.0.16.
--tls-version=protocol_list
The permissible TLS protocols for encrypted connections. The value is a list of one or more comma-separated protocol names. The protocols that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
--use-default
Execute noninteractively. This option can be used for unattended installation operations.
--user=user_name, -u user_name
The user name of the MySQL account to use for connecting to the server.

4.4.3 mysql_ssl_rsa_setup — Create SSL/RSA Files

This program creates the SSL certificate and key files and RSA key-pair files required to support secure connections using SSL and secure password exchange using RSA over unencrypted connections, if those files are missing. mysql_ssl_rsa_setup can also be used to create new SSL files if the existing ones have expired.

Note

mysql_ssl_rsa_setup uses the openssl command, so its use is contingent on having OpenSSL installed on your machine.

Another way to generate SSL and RSA files, for MySQL distributions compiled using OpenSSL, is to have the server generate them automatically. See Section 6.3.3.1, “Creating SSL and RSA Certificates and Keys using MySQL”.

Important

mysql_ssl_rsa_setup helps lower the barrier to using SSL by making it easier to generate the required files. However, certificates generated by mysql_ssl_rsa_setup are self-signed, which is not very secure. After you gain experience using the files created by mysql_ssl_rsa_setup, consider obtaining a CA certificate from a registered certificate authority.

Invoke mysql_ssl_rsa_setup like this:

mysql_ssl_rsa_setup [options]

Typical options are --datadir to specify where to create the files, and --verbose to see the openssl commands that mysql_ssl_rsa_setup executes.

mysql_ssl_rsa_setup attempts to create SSL and RSA files using a default set of file names. It works as follows:

mysql_ssl_rsa_setup checks for the openssl binary at the locations specified by the PATH environment variable. If openssl is not found, mysql_ssl_rsa_setup does nothing. If openssl is present, mysql_ssl_rsa_setup looks for default SSL and RSA files in the MySQL data directory specified by the --datadir option, or the compiled-in data directory if the --datadir option is not given.
mysql_ssl_rsa_setup checks the data directory for SSL files with the following names:
```
ca.pem
server-cert.pem
server-key.pem
```
If any of those files are present, mysql_ssl_rsa_setup creates no SSL files. Otherwise, it invokes openssl to create them, plus some additional files:
```
ca.pem               Self-signed CA certificate
ca-key.pem           CA private key
server-cert.pem      Server certificate
server-key.pem       Server private key
client-cert.pem      Client certificate
client-key.pem       Client private key
```
These files enable secure client connections using SSL; see Section 6.3.1, “Configuring MySQL to Use Encrypted Connections”.

mysql_ssl_rsa_setup checks the data directory for RSA files with the following names:

private_key.pem      Private member of private/public key pair
public_key.pem       Public member of private/public key pair

If any of these files are present, mysql_ssl_rsa_setup creates no RSA files. Otherwise, it invokes openssl to create them. These files enable secure password exchange using RSA over unencrypted connections for accounts authenticated by the sha256_password or caching_sha2_password plugin; see Section 6.4.1.3, “SHA-256 Pluggable Authentication”, and Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.

For information about the characteristics of files created by mysql_ssl_rsa_setup, see Section 6.3.3.1, “Creating SSL and RSA Certificates and Keys using MySQL”.

At startup, the MySQL server automatically uses the SSL files created by mysql_ssl_rsa_setup to enable SSL if no explicit SSL options are given other than --ssl (possibly along with ssl_cipher). If you prefer to designate the files explicitly, invoke clients with the --ssl-ca, --ssl-cert, and --ssl-key options at startup to name the ca.pem, server-cert.pem, and server-key.pem files, respectively.

The server also automatically uses the RSA files created by mysql_ssl_rsa_setup to enable RSA if no explicit RSA options are given.

If the server is SSL-enabled, clients use SSL by default for the connection. To specify certificate and key files explicitly, use the --ssl-ca, --ssl-cert, and --ssl-key options to name the ca.pem, client-cert.pem, and client-key.pem files, respectively. However, some additional client setup may be required first because mysql_ssl_rsa_setup by default creates those files in the data directory. The permissions for the data directory normally enable access only to the system account that runs the MySQL server, so client programs cannot use files located there. To make the files available, copy them to a directory that is readable (but not writable) by clients:

For local clients, the MySQL installation directory can be used. For example, if the data directory is a subdirectory of the installation directory and your current location is the data directory, you can copy the files like this:
```
cp ca.pem client-cert.pem client-key.pem ..
```
For remote clients, distribute the files using a secure channel to ensure they are not tampered with during transit.

If the SSL files used for a MySQL installation have expired, you can use mysql_ssl_rsa_setup to create new ones:

Stop the server.
Rename or remove the existing SSL files. You may wish to make a backup of them first. (The RSA files do not expire, so you need not remove them. mysql_ssl_rsa_setup can see that they exist and does not overwrite them.)
Run mysql_ssl_rsa_setup with the --datadir option to specify where to create the new files.
Restart the server.

mysql_ssl_rsa_setup supports the following command-line options, which can be specified on the command line or in the [mysql_ssl_rsa_setup] and [mysqld] groups of an option file. For information about option files used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.

Table 4.9 mysql_ssl_rsa_setup Options

Option Name	Description
--datadir	Path to data directory
--help	Display help message and exit
--suffix	Suffix for X.509 certificate Common Name attribute
--uid	Name of effective user to use for file permissions
--verbose	Verbose mode
--version	Display version information and exit

--help, ?
Display a help message and exit.
--datadir=dir_name
The path to the directory that mysql_ssl_rsa_setup should check for default SSL and RSA files and in which it should create files if they are missing. The default is the compiled-in data directory.
--suffix=str
The suffix for the Common Name attribute in X.509 certificates. The suffix value is limited to 17 characters. The default is based on the MySQL version number.
--uid=name, -v
The name of the user who should be the owner of any created files. The value is a user name, not a numeric user ID. In the absence of this option, files created by mysql_ssl_rsa_setup are owned by the user who executes it. This option is valid only if you execute the program as root on a system that supports the chown() system call.
--verbose, -v
Verbose mode. Produce more output about what the program does. For example, the program shows the openssl commands it runs, and produces output to indicate whether it skips SSL or RSA file creation because some default file already exists.
--version, -V
Display version information and exit.

4.4.4 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 macOS. 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 5.1.15, “MySQL Server Time Zone Support”.

mysql_tzinfo_to_sql can be invoked several ways:

mysql_tzinfo_to_sql tz_dir
mysql_tzinfo_to_sql tz_file tz_name
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:

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:

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:

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.

4.4.5 mysql_upgrade — Check and Upgrade MySQL Tables

Note

As of MySQL 8.0.16, the MySQL server performs the upgrade tasks previously handled by mysql_upgrade (for details, see Section 2.11.3, “What the MySQL Upgrade Process Upgrades”). Consequently, mysql_upgrade is unneeded and is deprecated as of that version; expect it to be removed in a future version of MySQL. Because mysql_upgrade no longer performs upgrade tasks, it exits with status 0 unconditionally.

Each time you upgrade MySQL, you should execute mysql_upgrade, which looks for incompatibilities with the upgraded MySQL server:

It upgrades the system tables in the mysql schema so that you can take advantage of new privileges or capabilities that might have been added.
It upgrades the Performance Schema, INFORMATION_SCHEMA, and sys schema.
It examines user schemas.

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 2.11.13, “Rebuilding or Repairing Tables or Indexes” for manual table repair strategies.

mysql_upgrade communicates directly with the MySQL server, sending it the SQL statements required to perform an upgrade.

Caution

You should always back up your current MySQL installation before performing an upgrade. See Section 7.2, “Database Backup Methods”.

Some upgrade incompatibilities may require special handling before upgrading your MySQL installation and running mysql_upgrade. See Section 2.11, “Upgrading MySQL”, for instructions on determining whether any such incompatibilities apply to your installation and how to handle them.

Use mysql_upgrade like this:

Ensure that the server is running.
Invoke mysql_upgrade to upgrade the system tables in the mysql schema and check and repair tables in other schemas:
```
mysql_upgrade [options]
```
Stop the server and restart it so that any system table changes take effect.

If you have multiple MySQL server instances to upgrade, invoke mysql_upgrade with connection parameters appropriate for connecting to each of the desired servers. For example, with servers running on the local host on parts 3306 through 3308, upgrade each of them by connecting to the appropriate port:

mysql_upgrade --protocol=tcp -P 3306 [other_options]
mysql_upgrade --protocol=tcp -P 3307 [other_options]
mysql_upgrade --protocol=tcp -P 3308 [other_options]

For local host connections on Unix, the --protocol=tcp option forces a connection using TCP/IP rather than the Unix socket file.

By default, mysql_upgrade runs as the MySQL root user. If the root password is expired when you run mysql_upgrade, it displays a message that your password is expired and that mysql_upgrade failed as a result. To correct this, reset the root password to unexpire it and run mysql_upgrade again. First, connect to the server as root:

shell> mysql -u root -p
Enter password: ****  <- enter root password here

Reset the password using ALTER USER:

mysql> ALTER USER USER() IDENTIFIED BY 'root-password';

Then exit mysql and run mysql_upgrade again:

shell> mysql_upgrade [options]

Note

If you run the server with the disabled_storage_engines system variable set to disable certain storage engines (for example, MyISAM), mysql_upgrade might fail with an error like this:

mysql_upgrade: [ERROR] 3161: Storage engine MyISAM is disabled
(Table creation is disallowed).

To handle this, restart the server with disabled_storage_engines disabled. Then you should be able to run mysql_upgrade successfully. After that, restart the server with disabled_storage_engines set to its original value.

Unless invoked with the --upgrade-system-tables option, mysql_upgrade processes all tables in all user schemas as necessary. Table checking 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. Table checking uses the FOR UPGRADE option of the CHECK TABLE statement. For details about what this option entails, see Section 13.7.3.2, “CHECK TABLE Statement”.

mysql_upgrade marks all checked and repaired tables with the current MySQL version number. This ensures that the next time you run mysql_upgrade with the same version of the server, it can be determined whether there is any need to check or repair a given table again.

mysql_upgrade 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.

Note

The mysql_upgrade_info file is deprecated; expect it to be removed in a future version of MySQL.

mysql_upgrade checks mysql.user system table rows and, for any row with an empty plugin column, sets that column to 'mysql_native_password' if the credentials use a hash format compatible with that plugin. Rows with a pre-4.1 password hash must be upgraded manually.

mysql_upgrade does not upgrade the contents of the time zone tables or help tables. For upgrade instructions, see Section 5.1.15, “MySQL Server Time Zone Support”, and Section 5.1.17, “Server-Side Help Support”.

Unless invoked with the --skip-sys-schema option, mysql_upgrade installs the sys schema if it is not installed, and upgrades it to the current version otherwise. An error occurs if a sys schema exists but has no version view, on the assumption that its absence indicates a user-created schema:

A sys schema exists with no sys.version view. If
you have a user created sys schema, this must be renamed for the
upgrade to succeed.

To upgrade in this case, remove or rename the existing sys schema first.

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. For information about option files used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.

Table 4.10 mysql_upgrade Options

Option Name	Description	Introduced	Deprecated
--bind-address	Use specified network interface to connect to MySQL Server
--character-sets-dir	Directory where character sets are installed
--compress	Compress all information sent between client and server		8.0.18
--compression-algorithms	Permitted compression algorithms for connections to server	8.0.18
--debug	Write debugging log
--debug-check	Print debugging information when program exits
--debug-info	Print debugging information, memory, and CPU statistics when program exits
--default-auth	Authentication plugin to use
--default-character-set	Specify default character set
--defaults-extra-file	Read named option file in addition to usual option files
--defaults-file	Read only named option file
--defaults-group-suffix	Option group suffix value
--force	Force execution even if mysql_upgrade has already been executed for current MySQL version
--get-server-public-key	Request RSA public key from server
--help	Display help message and exit
--host	Host on which MySQL server is located
--login-path	Read login path options from .mylogin.cnf
--max-allowed-packet	Maximum packet length to send to or receive from server
--net-buffer-length	Buffer size for TCP/IP and socket communication
--no-defaults	Read no option files
--password	Password to use when connecting to server
--pipe	Connect to server using named pipe (Windows only)
--plugin-dir	Directory where plugins are installed
--port	TCP/IP port number for connection
--print-defaults	Print default options
--protocol	Transport protocol to use
--server-public-key-path	Path name to file containing RSA public key
--shared-memory-base-name	Shared-memory name for shared-memory connections (Windows only)
--skip-sys-schema	Do not install or upgrade sys schema
--socket	Unix socket file or Windows named pipe to use
--ssl-ca	File that contains list of trusted SSL Certificate Authorities
--ssl-capath	Directory that contains trusted SSL Certificate Authority certificate files
--ssl-cert	File that contains X.509 certificate
--ssl-cipher	Permissible ciphers for connection encryption
--ssl-crl	File that contains certificate revocation lists
--ssl-crlpath	Directory that contains certificate revocation-list files
--ssl-fips-mode	Whether to enable FIPS mode on client side
--ssl-key	File that contains X.509 key
--ssl-mode	Desired security state of connection to server
--tls-ciphersuites	Permissible TLSv1.3 ciphersuites for encrypted connections	8.0.16
--tls-version	Permissible TLS protocols for encrypted connections
--upgrade-system-tables	Update only system tables, not user schemas
--user	MySQL user name to use when connecting to server
--verbose	Verbose mode
--version-check	Check for proper server version
--write-binlog	Write all statements to binary log
--zstd-compression-level	Compression level for connections to server that use zstd compression	8.0.18

--help
Display a short help message and exit.
--bind-address=ip_address
On a computer having multiple network interfaces, use this option to select which interface to use for connecting to the MySQL server.
--character-sets-dir=dir_name
The directory where character sets are installed. See Section 10.15, “Character Set Configuration”.
--compress, -C
Compress all information sent between the client and the server if possible. See Section 4.2.8, “Connection Compression Control”.
As of MySQL 8.0.18, this option is deprecated. Expect it to be removed in a future version of MySQL. See Configuring Legacy Connection Compression.
--compression-algorithms=value
The permitted compression algorithms for connections to the server. The available algorithms are the same as for the protocol_compression_algorithms system variable. The default value is uncompressed.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.
--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_upgrade.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
A hint about which client-side authentication plugin to use. See Section 6.2.17, “Pluggable Authentication”.
--default-character-set=charset_name
Use charset_name as the default character set. See Section 10.15, “Character Set Configuration”.
--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, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-file=file_name
Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-group-suffix=str
Read not only the usual option groups, but also groups with the usual names and a suffix of str. For example, mysql_upgrade normally reads the [client] and [mysql_upgrade] groups. If this option is given as --defaults-group-suffix=_other, mysql_upgrade also reads the [client_other] and [mysql_upgrade_other] groups.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--force
Ignore the mysql_upgrade_info file and force execution even if mysql_upgrade has already been executed for the current version of MySQL.
--get-server-public-key
Request from the server the public key required for RSA key pair-based password exchange. This option applies to clients that authenticate with the caching_sha2_password authentication plugin. For that plugin, the server does not send the public key unless requested. This option is ignored for accounts that do not authenticate with that plugin. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For information about the caching_sha2_password plugin, see Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--host=host_name, -h host_name
Connect to the MySQL server on the given host.
--login-path=name
Read options from the named login path in the .mylogin.cnf login path file. A “login path” is an option group containing options that specify which MySQL server to connect to and which account to authenticate as. To create or modify a login path file, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--max-allowed-packet=value
The maximum size of the buffer for client/server communication. The default value is 24MB. The minimum and maximum values are 4KB and 2GB.
--net-buffer-length=value
The initial size of the buffer for client/server communication. The default value is 1MB − 1KB. The minimum and maximum values are 4KB and 16MB.
--no-defaults
Do not read any option files. If program startup fails due to reading unknown options from an option file, --no-defaults can be used to prevent them from being read.
The exception is that the .mylogin.cnf file is read in all cases, if it exists. This permits passwords to be specified in a safer way than on the command line even when --no-defaults is used. To create .mylogin.cnf, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--password[=password], -p[password]
The password of the MySQL account used for connecting to the server. The password value is optional. If not given, mysql_upgrade prompts for one. If given, there must be no space between --password= or -p and the password following it. If no password option is specified, the default is to send no password.
Specifying a password on the command line should be considered insecure. To avoid giving the password on the command line, use an option file. See Section 6.1.2.1, “End-User Guidelines for Password Security”.
To explicitly specify that there is no password and that mysql_upgrade should not prompt for one, use the --skip-password option.
--pipe, -W
On Windows, connect to the server using a named pipe. This option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--plugin-dir=dir_name
The directory in which to look for plugins. Specify this option if the --default-auth option is used to specify an authentication plugin but mysql_upgrade does not find it. See Section 6.2.17, “Pluggable Authentication”.
--port=port_num, -P port_num
For TCP/IP connections, the port number to use.
--print-defaults
Print the program name and all options that it gets from option files.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The transport protocol to use for connecting to the server. It is useful when the other connection parameters normally result in use of a protocol other than the one you want. For details on the permissible values, see Section 4.2.7, “Connection Transport Protocols”.
--server-public-key-path=file_name
The path name to a file in PEM format containing a client-side copy of the public key required by the server for RSA key pair-based password exchange. This option applies to clients that authenticate with the sha256_password or caching_sha2_password authentication plugin. This option is ignored for accounts that do not authenticate with one of those plugins. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For sha256_password, this option applies only if MySQL was built using OpenSSL.
For information about the sha256_password and caching_sha2_password plugins, see Section 6.4.1.3, “SHA-256 Pluggable Authentication”, and Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--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.
This option applies only if the server was started with the shared_memory system variable enabled to support shared-memory connections.
--skip-sys-schema
By default, mysql_upgrade installs the sys schema if it is not installed, and upgrades it to the current version otherwise. The --skip-sys-schema option suppresses this behavior.
--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.
On Windows, this option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--ssl*
Options that begin with --ssl specify whether to connect to the server using encryption and indicate where to find SSL keys and certificates. See Command Options for Encrypted Connections.
--ssl-fips-mode={OFF|ON|STRICT}
Controls whether to enable FIPS mode on the client side. The --ssl-fips-mode option differs from other --ssl-xxx options in that it is not used to establish encrypted connections, but rather to affect which cryptographic operations to permit. See Section 6.8, “FIPS Support”.
These --ssl-fips-mode values are permitted:
- OFF: Disable FIPS mode.
- ON: Enable FIPS mode.
- STRICT: Enable “strict” FIPS mode.
Note

If the OpenSSL FIPS Object Module is not available, the only permitted value for --ssl-fips-mode is OFF. In this case, setting --ssl-fips-mode to ON or STRICT causes the client to produce a warning at startup and to operate in non-FIPS mode.
--tls-ciphersuites=ciphersuite_list
The permissible ciphersuites for encrypted connections that use TLSv1.3. The value is a list of one or more colon-separated ciphersuite names. The ciphersuites that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
This option was added in MySQL 8.0.16.
--tls-version=protocol_list
The permissible TLS protocols for encrypted connections. The value is a list of one or more comma-separated protocol names. The protocols that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
--upgrade-system-tables, -s
Upgrade only the system tables in the mysql schema, do not upgrade user schemas.
--user=user_name, -u user_name
The user name of the MySQL account to use for connecting to the server. The default user name is root.
--verbose
Verbose mode. Print more information about what the program does.
--version-check, -k
Check the version of the server to which mysql_upgrade is connecting to verify that it is the same as the version for which mysql_upgrade was built. If not, mysql_upgrade exits. This option is enabled by default; to disable the check, use --skip-version-check.
--write-binlog
By default, binary logging by mysql_upgrade is disabled. Invoke the program with --write-binlog if you want its actions to be written to the binary log.
When the server is running with global transaction identifiers (GTIDs) enabled (gtid_mode=ON), do not enable binary logging by mysql_upgrade.
--zstd-compression-level=level
The compression level to use for connections to the server that use the zstd compression algorithm. The permitted levels are from 1 to 22, with larger values indicating increasing levels of compression. The default zstd compression level is 3. The compression level setting has no effect on connections that do not use zstd compression.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.

4.5 Client Programs

4.5.1 mysql — The MySQL Command-Line Client
4.5.2 mysqladmin — A MySQL Server Administration Program
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 mysqlpump — A Database Backup Program
4.5.7 mysqlshow — Display Database, Table, and Column Information
4.5.8 mysqlslap — A Load Emulation Client

This section describes client programs that connect to the MySQL server.

4.5.1 mysql — The MySQL Command-Line Client

4.5.1.1 mysql Client Options
4.5.1.2 mysql Client Commands
4.5.1.3 mysql Client Logging
4.5.1.4 mysql Client Server-Side Help
4.5.1.5 Executing SQL Statements from a Text File
4.5.1.6 mysql Client Tips

mysql is a simple SQL shell with input line editing 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().

Note

Alternatively, MySQL Shell offers access to the X DevAPI. For details, see MySQL Shell 8.0 (part of MySQL 8.0).

Using mysql is very easy. Invoke it from the prompt of your command interpreter as follows:

mysql db_name

Or:

mysql --user=user_name --password db_name

In this case, you'll need to enter your password in response to the prompt that mysql displays:

Enter password: your_password

Then type an SQL statement, end it with ;, \g, or \G and press Enter.

Typing Control+C interrupts the current statement if there is one, or cancels any partial input line otherwise.

You can execute SQL statements in a script file (batch file) like this:

mysql db_name < script.sql > output.tab

On Unix, the mysql client logs statements executed interactively to a history file. See Section 4.5.1.3, “mysql Client Logging”.

4.5.1.1 mysql Client 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. For information about option files used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.

Table 4.11 mysql Client Options

Option Name	Description	Introduced	Deprecated
--auto-rehash	Enable automatic rehashing
--auto-vertical-output	Enable automatic vertical result set display
--batch	Do not use history file
--binary-as-hex	Display binary values in hexadecimal notation
--binary-mode	Disable \r\n - to - \n translation and treatment of \0 as end-of-query
--bind-address	Use specified network interface to connect to MySQL Server
--character-sets-dir	Directory where character sets are installed
--column-names	Write column names in results
--column-type-info	Display result set metadata
--comments	Whether to retain or strip comments in statements sent to the server
--compress	Compress all information sent between client and server		8.0.18
--compression-algorithms	Permitted compression algorithms for connections to server	8.0.18
--connect-expired-password	Indicate to server that client can handle expired-password sandbox mode
--connect-timeout	Number of seconds before connection timeout
--database	The database to use
--debug	Write debugging log; supported only if MySQL was built with debugging support
--debug-check	Print debugging information when program exits
--debug-info	Print debugging information, memory, and CPU statistics when program exits
--default-auth	Authentication plugin to use
--default-character-set	Specify default character set
--defaults-extra-file	Read named option file in addition to usual option files
--defaults-file	Read only named option file
--defaults-group-suffix	Option group suffix value
--delimiter	Set the statement delimiter
--dns-srv-name	Use DNS SRV lookup for host information	8.0.22
--enable-cleartext-plugin	Enable cleartext authentication plugin
--execute	Execute the statement and quit
--force	Continue even if an SQL error occurs
--get-server-public-key	Request RSA public key from server
--help	Display help message and exit
--histignore	Patterns specifying which statements to ignore for logging
--host	Host on which MySQL server is located
--html	Produce HTML output
--ignore-spaces	Ignore spaces after function names
--init-command	SQL statement to execute after connecting
--line-numbers	Write line numbers for errors
--load-data-local-dir	Directory for files named in LOAD DATA LOCAL statements	8.0.21
--local-infile	Enable or disable for LOCAL capability for LOAD DATA
--login-path	Read login path options from .mylogin.cnf
--max-allowed-packet	Maximum packet length to send to or receive from server
--max-join-size	The automatic limit for rows in a join when using --safe-updates
--named-commands	Enable named mysql commands
--net-buffer-length	Buffer size for TCP/IP and socket communication
--network-namespace	Specify network namespace	8.0.22
--no-auto-rehash	Disable automatic rehashing
--no-beep	Do not beep when errors occur
--no-defaults	Read no option files
--one-database	Ignore statements except those for the default database named on the command line
--pager	Use the given command for paging query output
--password	Password to use when connecting to server
--pipe	Connect to server using named pipe (Windows only)
--plugin-dir	Directory where plugins are installed
--port	TCP/IP port number for connection
--print-defaults	Print default options
--prompt	Set the prompt to the specified format
--protocol	Transport protocol to use
--quick	Do not cache each query result
--raw	Write column values without escape conversion
--reconnect	If the connection to the server is lost, automatically try to reconnect
--safe-updates, --i-am-a-dummy	Allow only UPDATE and DELETE statements that specify key values
--select-limit	The automatic limit for SELECT statements when using --safe-updates
--server-public-key-path	Path name to file containing RSA public key
--shared-memory-base-name	Shared-memory name for shared-memory connections (Windows only)
--show-warnings	Show warnings after each statement if there are any
--sigint-ignore	Ignore SIGINT signals (typically the result of typing Control+C)
--silent	Silent mode
--skip-auto-rehash	Disable automatic rehashing
--skip-column-names	Do not write column names in results
--skip-line-numbers	Skip line numbers for errors
--skip-named-commands	Disable named mysql commands
--skip-pager	Disable paging
--skip-reconnect	Disable reconnecting
--socket	Unix socket file or Windows named pipe to use
--ssl-ca	File that contains list of trusted SSL Certificate Authorities
--ssl-capath	Directory that contains trusted SSL Certificate Authority certificate files
--ssl-cert	File that contains X.509 certificate
--ssl-cipher	Permissible ciphers for connection encryption
--ssl-crl	File that contains certificate revocation lists
--ssl-crlpath	Directory that contains certificate revocation-list files
--ssl-fips-mode	Whether to enable FIPS mode on client side
--ssl-key	File that contains X.509 key
--ssl-mode	Desired security state of connection to server
--syslog	Log interactive statements to syslog
--table	Display output in tabular format
--tee	Append a copy of output to named file
--tls-ciphersuites	Permissible TLSv1.3 ciphersuites for encrypted connections	8.0.16
--tls-version	Permissible TLS protocols for encrypted connections
--unbuffered	Flush the buffer after each query
--user	MySQL user name to use when connecting to server
--verbose	Verbose mode
--version	Display version information and exit
--vertical	Print query output rows vertically (one line per column value)
--wait	If the connection cannot be established, wait and retry instead of aborting
--xml	Produce XML output
--zstd-compression-level	Compression level for connections to server that use zstd compression	8.0.18

--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 or its \# shortcut 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.

Note

This feature requires a MySQL client that is compiled with the readline library. Typically, the readline library is not available on Windows.
--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.)
--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.
--binary-as-hex
When this option is given, mysql displays binary data using hexadecimal notation (0xvalue). This occurs whether the overall output display format is tabular, vertical, HTML, or XML.
--binary-as-hex when enabled affects display of all binary strings, including those returned by functions such as CHAR() and UNHEX(). The following example demonistrates this using the ASCII code for A (65 decimal, 41 hexadecimal):
- --binary-as-hex disabled:
```
mysql> SELECT CHAR(0x41), UNHEX('41');
+------------+-------------+
| CHAR(0x41) | UNHEX('41') |
+------------+-------------+
| A          | A           |
+------------+-------------+
```
- --binary-as-hex enabled:
```
mysql> SELECT CHAR(0x41), UNHEX('41');
+------------------------+--------------------------+
| CHAR(0x41)             | UNHEX('41')              |
+------------------------+--------------------------+
| 0x41                   | 0x41                     |
+------------------------+--------------------------+
```
To write a binary string expression so that it displays as a character string regardless of whether --binary-as-hex is enabled, use these techniques:
- The CHAR() function has a USING charset clause:
```
mysql> SELECT CHAR(0x41 USING utf8mb4);
+--------------------------+
| CHAR(0x41 USING utf8mb4) |
+--------------------------+
| A                        |
+--------------------------+
```
- More generally, use CONVERT() to convert an expression to a given character set:
```
mysql> SELECT CONVERT(UNHEX('41') USING utf8mb4);
+------------------------------------+
| CONVERT(UNHEX('41') USING utf8mb4) |
+------------------------------------+
| A                                  |
+------------------------------------+
```
As of MySQL 8.0.19, when mysql operates in interactive mode, this option is enabled by default. In addition, output from the status (or \s) command includes this line when the option is enabled implicitly or explicitly:
```
Binary data as: Hexadecimal
```
To disable hexadecimal notation, use --skip-binary-as-hex
--binary-mode
This option helps when processing mysqlbinlog output that may contain BLOB values. By default, mysql translates \r\n in statement strings to \n and interprets \0 as the statement terminator. --binary-mode disables both features. It also disables all mysql commands except charset and delimiter in noninteractive mode (for input piped to mysql or loaded using the source command).
--bind-address=ip_address
On a computer having multiple network interfaces, use this option to select which interface to use for connecting to the MySQL server.
--character-sets-dir=dir_name
The directory where character sets are installed. See Section 10.15, “Character Set Configuration”.
--column-names
Write column names in results.
--column-type-info
Display result set metadata. This information corresponds to the contents of C API MYSQL_FIELD data structures. See C API Data Structures.
--comments, -c
Whether to strip or preserve comments in statements sent to the server. The default is --skip-comments (strip comments), enable with --comments (preserve comments).

Note

The mysql client always passes optimizer hints to the server, regardless of whether this option is given.
Comment stripping is deprecated. Expect this feature and the options to control it to be removed in a future MySQL release.
--compress, -C
Compress all information sent between the client and the server if possible. See Section 4.2.8, “Connection Compression Control”.
As of MySQL 8.0.18, this option is deprecated. Expect it be removed in a future version of MySQL. See Configuring Legacy Connection Compression.
--compression-algorithms=value
The permitted compression algorithms for connections to the server. The available algorithms are the same as for the protocol_compression_algorithms system variable. The default value is uncompressed.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.
--connect-expired-password
Indicate to the server that the client can handle sandbox mode if the account used to connect has an expired password. This can be useful for noninteractive invocations of mysql because normally the server disconnects noninteractive clients that attempt to connect using an account with an expired password. (See Section 6.2.16, “Server Handling of Expired Passwords”.)
--connect-timeout=value
The number of seconds before connection timeout. (Default value is 0.)
--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.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--debug-check
Print some debugging information when the program exits.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--debug-info, -T
Print debugging information and memory and CPU usage statistics when the program exits.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--default-auth=plugin
A hint about which client-side authentication plugin to use. See Section 6.2.17, “Pluggable Authentication”.
--default-character-set=charset_name
Use charset_name as the default character set for the client and connection.
This option can be useful if the operating system uses one character set and the mysql client by default uses another. In this case, output may be formatted incorrectly. You can usually fix such issues by using this option to force the client to use the system character set instead.
For more information, see Section 10.4, “Connection Character Sets and Collations”, and Section 10.15, “Character Set Configuration”.
--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, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-file=file_name
Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
Exception: Even with --defaults-file, client programs read .mylogin.cnf.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-group-suffix=str
Read not only the usual option groups, but also groups with the usual names and a suffix of str. For example, mysql normally reads the [client] and [mysql] groups. If this option is given as --defaults-group-suffix=_other, mysql also reads the [client_other] and [mysql_other] groups.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--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 Client Commands”.
--dns-srv-name=name
Specifies the name of a DNS SRV record that determines the candidate hosts to use for establishing a connection to a MySQL server. For information about DNS SRV support in MySQL, see Section 4.2.6, “Connecting to the Server Using DNS SRV Records”.
Suppose that DNS is configured with this SRV information for the example.com domain:
```
Name                     TTL   Class   Priority Weight Port Target
_mysql._tcp.example.com. 86400 IN SRV  0        5      3306 host1.example.com
_mysql._tcp.example.com. 86400 IN SRV  0        10     3306 host2.example.com
_mysql._tcp.example.com. 86400 IN SRV  10       5      3306 host3.example.com
_mysql._tcp.example.com. 86400 IN SRV  20       5      3306 host4.example.com
```
To use that DNS SRV record, invoke mysql like this:
```
mysql --dns-srv-name=_mysql._tcp.example.com
```
mysql then attempts a connection to each server in the group until a successful connection is established. A failure to connect occurs only if a connection cannot be established to any of the servers. The priority and weight values in the DNS SRV record determine the order in which servers should be tried.
When invoked with --dns-srv-name, mysql attempts to establish TCP connections only.
The --dns-srv-name option takes precedence over the --host option if both are given. --dns-srv-name causes connection establishment to use the mysql_real_connect_dns_srv() C API function rather than mysql_real_connect(). However, if the connect command is subsequently used at runtime and specifies a host name argument, that host name takes precedence over any --dns-srv-name option given at mysql startup to specify a DNS SRV record.
This option was added in MySQL 8.0.22.
--enable-cleartext-plugin
Enable the mysql_clear_password cleartext authentication plugin. (See Section 6.4.1.4, “Client-Side Cleartext Pluggable Authentication”.)
--execute=statement, -e statement
Execute the statement and quit. The default output format is like that produced with --batch. See Section 4.2.2.1, “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.
--get-server-public-key
Request from the server the public key required for RSA key pair-based password exchange. This option applies to clients that authenticate with the caching_sha2_password authentication plugin. For that plugin, the server does not send the public key unless requested. This option is ignored for accounts that do not authenticate with that plugin. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For information about the caching_sha2_password plugin, see Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--histignore
A list of one or more colon-separated patterns specifying statements to ignore for logging purposes. These patterns are added to the default pattern list ("*IDENTIFIED*:*PASSWORD*"). The value specified for this option affects logging of statements written to the history file, and to syslog if the --syslog option is given. For more information, see Section 4.5.1.3, “mysql Client Logging”.
--host=host_name, -h host_name
Connect to the MySQL server on the given host.
The --dns-srv-name option takes precedence over the --host option if both are given. --dns-srv-name causes connection establishment to use the mysql_real_connect_dns_srv() C API function rather than mysql_real_connect(). However, if the connect command is subsequently used at runtime and specifies a host name argument, that host name takes precedence over any --dns-srv-name option given at mysql startup to specify a DNS SRV record.
--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 5.1.11, “Server SQL Modes”).
--init-command=str
SQL statement to execute after connecting to the server. If auto-reconnect is enabled, the statement is executed again after reconnection occurs.
--line-numbers
Write line numbers for errors. Disable this with --skip-line-numbers.
--load-data-local-dir=dir_name
This option affects the client-side LOCAL capability for LOAD DATA operations. It specifies the directory in which files named in LOAD DATA LOCAL statements must be located. The effect of --load-data-local-dir depends on whether LOCAL data loading is enabled or disabled:
- If LOCAL data loading is enabled, either by default in the MySQL client library or by specifying --local-infile[=1], the --load-data-local-dir option is ignored.
- If LOCAL data loading is disabled, either by default in the MySQL client library or by specifying --local-infile=0, the --load-data-local-dir option applies.
When --load-data-local-dir applies, the option value designates the directory in which local data files must be located. Comparison of the directory path name and the path name of files to be loaded is case-sensitive regardless of the case sensitivity of the underlying file system. If the option value is the empty string, it names no directory, with the result that no files are permitted for local data loading.
For example, to explicitly disable local data loading except for files located in the /my/local/data directory, invoke mysql like this:
```
mysql --local-infile=0 --load-data-local-dir=/my/local/data
```
When both --local-infile and --load-data-local-dir are given, the order in which they are given does not matter.
Successful use of LOCAL load operations within mysql also requires that the server permits local loading; see Section 6.1.6, “Security Considerations for LOAD DATA LOCAL”
The --load-data-local-dir option was added in MySQL 8.0.21.
--local-infile[={0|1}]
By default, LOCAL capability for LOAD DATA is determined by the default compiled into the MySQL client library. To enable or disable LOCAL data loading explicitly, use the --local-infile option. When given with no value, the option enables LOCAL data loading. When given as --local-infile=0 or --local-infile=1, the option disables or enables LOCAL data loading.
If LOCAL capability is disabled, the --load-data-local-dir option can be used to permit restricted local loading of files located in a designated directory.
Successful use of LOCAL load operations within mysql also requires that the server permits local loading; see Section 6.1.6, “Security Considerations for LOAD DATA LOCAL”
--login-path=name
Read options from the named login path in the .mylogin.cnf login path file. A “login path” is an option group containing options that specify which MySQL server to connect to and which account to authenticate as. To create or modify a login path file, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--max-allowed-packet=value
The maximum size of the buffer for client/server communication. The default is 16MB, the maximum is 1GB.
--max-join-size=value
The automatic limit for rows in a join when using --safe-updates. (Default value is 1,000,000.)
--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 Client Commands”.
--net-buffer-length=value
The buffer size for TCP/IP and socket communication. (Default value is 16KB.)
--network-namespace=name
The network namespace to use for TCP/IP connections. If omitted, the connection uses the default (global) namespace. For information about network namespaces, see Section 5.1.14, “Network Namespace Support”.
This option was added in MySQL 8.0.22. It is available only on platforms that implement network namespace support.
--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-defaults
Do not read any option files. If program startup fails due to reading unknown options from an option file, --no-defaults can be used to prevent them from being read.
The exception is that the .mylogin.cnf file is read in all cases, if it exists. This permits passwords to be specified in a safer way than on the command line even when --no-defaults is used. To create .mylogin.cnf, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--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 Client Commands”, discusses output paging further.
--password[=password], -p[password]
The password of the MySQL account used for connecting to the server. The password value is optional. If not given, mysql prompts for one. If given, there must be no space between --password= or -p and the password following it. If no password option is specified, the default is to send no password.
Specifying a password on the command line should be considered insecure. To avoid giving the password on the command line, use an option file. See Section 6.1.2.1, “End-User Guidelines for Password Security”.
To explicitly specify that there is no password and that mysql should not prompt for one, use the --skip-password option.
--pipe, -W
On Windows, connect to the server using a named pipe. This option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--plugin-dir=dir_name
The directory in which to look for plugins. Specify this option if the --default-auth option is used to specify an authentication plugin but mysql does not find it. See Section 6.2.17, “Pluggable Authentication”.
--port=port_num, -P port_num
For TCP/IP connections, the port number to use.
--print-defaults
Print the program name and all options that it gets from option files.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--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 Client Commands”.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The transport protocol to use for connecting to the server. It is useful when the other connection parameters normally result in use of a protocol other than the one you want. For details on the permissible values, see Section 4.2.7, “Connection Transport Protocols”.
--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
If this option is enabled, UPDATE and DELETE statements that do not use a key in the WHERE clause or a LIMIT clause produce an error. In addition, restrictions are placed on SELECT statements that produce (or are estimated to produce) very large result sets. If you have set this option in an option file, you can use --skip-safe-updates on the command line to override it. For more information about this option, see Using Safe-Updates Mode (--safe-updates).
--select-limit=value
The automatic limit for SELECT statements when using --safe-updates. (Default value is 1,000.)
--server-public-key-path=file_name
The path name to a file in PEM format containing a client-side copy of the public key required by the server for RSA key pair-based password exchange. This option applies to clients that authenticate with the sha256_password or caching_sha2_password authentication plugin. This option is ignored for accounts that do not authenticate with one of those plugins. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For sha256_password, this option applies only if MySQL was built using OpenSSL.
For information about the sha256_password and caching_sha2_password plugins, see Section 6.4.1.3, “SHA-256 Pluggable Authentication”, and Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--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.
This option applies only if the server was started with the shared_memory system variable enabled to support shared-memory connections.
--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).
Without this option, typing Control+C interrupts the current statement if there is one, or cancels any partial input line otherwise.
--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.
On Windows, this option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--ssl*
Options that begin with --ssl specify whether to connect to the server using encryption and indicate where to find SSL keys and certificates. See Command Options for Encrypted Connections.
--ssl-fips-mode={OFF|ON|STRICT}
Controls whether to enable FIPS mode on the client side. The --ssl-fips-mode option differs from other --ssl-xxx options in that it is not used to establish encrypted connections, but rather to affect which cryptographic operations to permit. See Section 6.8, “FIPS Support”.
These --ssl-fips-mode values are permitted:
- OFF: Disable FIPS mode.
- ON: Enable FIPS mode.
- STRICT: Enable “strict” FIPS mode.
Note

If the OpenSSL FIPS Object Module is not available, the only permitted value for --ssl-fips-mode is OFF. In this case, setting --ssl-fips-mode to ON or STRICT causes the client to produce a warning at startup and to operate in non-FIPS mode.
--syslog, -j
This option causes mysql to send interactive statements to the system logging facility. On Unix, this is syslog; on Windows, it is the Windows Event Log. The destination where logged messages appear is system dependent. On Linux, the destination is often the /var/log/messages file.
Here is a sample of output generated on Linux by using --syslog. This output is formatted for readability; each logged message actually takes a single line.
```
Mar  7 12:39:25 myhost MysqlClient[20824]:
  SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23,
  DB_SERVER:'127.0.0.1', DB:'--', QUERY:'USE test;'
Mar  7 12:39:28 myhost MysqlClient[20824]:
  SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23,
  DB_SERVER:'127.0.0.1', DB:'test', QUERY:'SHOW TABLES;'
```
For more information, see Section 4.5.1.3, “mysql Client Logging”.
--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 Client Commands”, discusses tee files further.
--tls-ciphersuites=ciphersuite_list
The permissible ciphersuites for encrypted connections that use TLSv1.3. The value is a list of one or more colon-separated ciphersuite names. The ciphersuites that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
This option was added in MySQL 8.0.16.
--tls-version=protocol_list
The permissible TLS protocols for encrypted connections. The value is a list of one or more comma-separated protocol names. The protocols that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
--unbuffered, -n
Flush the buffer after each query.
--user=user_name, -u user_name
The user name of the MySQL account to use for 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>

--zstd-compression-level=level
The compression level to use for connections to the server that use the zstd compression algorithm. The permitted levels are from 1 to 22, with larger values indicating increasing levels of compression. The default zstd compression level is 3. The compression level setting has no effect on connections that do not use zstd compression.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.

4.5.1.2 mysql Client 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 the current input statement.
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.
resetconnection(\x) Clean session context.
query_attributes(\) Sets string parameters (name1 value1 name2 value2 ...)
for the next query to pick up.

For server side help, type 'help contents'

If mysql is invoked with the --binary-mode option, all mysql commands are disabled except charset and delimiter in noninteractive mode (for input piped to mysql or loaded using the source command).

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 multiple-line /* ... */ comments is not supported. Short-form commands do work within single-line /*! ... */ version comments, as do /*+ ... */ optimizer-hint comments, which are stored in object definitions. If there is a concern that optimizer-hint comments may be stored in object definitions so that dump files when reloaded with mysql would result in execution of such commands, either invoke mysql with the --binary-mode option or use a reload client other than mysql.

help [arg], \h [arg], \? [arg], ? [arg]
Display a help message listing the available mysql commands.
If you provide an argument to the help command, mysql uses it as a search string to access server-side help from the contents of the MySQL Reference Manual. For more information, see Section 4.5.1.4, “mysql Client 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.
If the connect command specifies a host name argument, that host takes precedence over any --dns-srv-name option given at mysql startup to specify a DNS SRV record.
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 ('), double 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, it is not possible 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 C API Multiple Statement Execution Support), and for parsing the body of stored procedures and functions, triggers, and events (see Section 25.1, “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
Disable 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>.
query_attributes name value [name value ...]
Define query attributes that apply to the next query sent to the server. For discussion of the purpose and use of query attributes, see Section 9.6, “Query Attributes”.
The query_attributes command follows these rules:
- The format and quoting rules for attribute names and values are the same as for the delimiter command.
- The command permits up to 32 attribute name/value pairs. Names and values may be up to 1024 characters long. If a name is given without a value, an error occurs.
- If multiple query_attributes commands are issued prior to query execution, only the last command applies. After sending the query, mysql clears the attribute set.
- If multiple attributes are defined with the same name, attempts to retrieve the attribute value have an undefined result.
- An attribute defined with an empty name cannot be retrieved by name.
- If a reconnect occurs while mysql executes the query, mysql restores the attributes after reconnecting so the query can be executed again with the same attributes.
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.)
resetconnection, \x
Reset the connection to clear the session state. This includes clearing any current query attributes defined using the query_attributes command.
Resetting a connection has effects similar to mysql_change_user() or an auto-reconnect except that the connection is not closed and reopened, and re-authentication is not done. See mysql_change_user(), and C API Automatic Reconnection Control.
This example shows how resetconnection clears a value maintained in the session state:
```
mysql> SELECT LAST_INSERT_ID(3);
+-------------------+
| LAST_INSERT_ID(3) |
+-------------------+
|                 3 |
+-------------------+

mysql> SELECT LAST_INSERT_ID();
+------------------+
| LAST_INSERT_ID() |
+------------------+
|                3 |
+------------------+

mysql> resetconnection;

mysql> SELECT LAST_INSERT_ID();
+------------------+
| LAST_INSERT_ID() |
+------------------+
|                0 |
+------------------+
```
source file_name, \. file_name
Read the named file and executes the statements contained therein. On Windows, specify path name separators as / or \\.
Quote characters are taken as part of the file name itself. For best results, the name should not include space characters.
status, \s
Provide status information about the connection and the server you are using. If you are running with --safe-updates enabled, 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.
Prior to MySQL 8.0.19, the system command works only in Unix. As of 8.0.19, it also works on Windows.
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:
```
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.

Option	Description
`\C`	The current connection identifier
`\c`	A counter that increments for each statement you issue
`\D`	The full current date
`\d`	The default database
`\h`	The server host
`\l`	The current delimiter
`\m`	Minutes of the current time
`\n`	A newline character
`\O`	The current month in three-letter format (Jan, Feb, …)
`\o`	The current month in numeric format
`\P`	am/pm
`\p`	The current TCP/IP port or socket file
`\R`	The current time, in 24-hour military time (0–23)
`\r`	The current time, standard 12-hour time (1–12)
`\S`	Semicolon
`\s`	Seconds of the current time
`\t`	A tab character
`\U`	Your full `user_name@host_name` account name
`\u`	Your user name
`\v`	The server version
`\w`	The current day of the week in three-letter format (Mon, Tue, …)
`\Y`	The current year, four digits
`\y`	The 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:
```
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 4.2.2.2, “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 Client Logging

The mysql client can do these types of logging for statements executed interactively:

On Unix, mysql writes the statements to a history file. By default, this file is named .mysql_history in your home directory. To specify a different file, set the value of the MYSQL_HISTFILE environment variable.
On all platforms, if the --syslog option is given, mysql writes the statements to the system logging facility. On Unix, this is syslog; on Windows, it is the Windows Event Log. The destination where logged messages appear is system dependent. On Linux, the destination is often the /var/log/messages file.

The following discussion describes characteristics that apply to all logging types and provides information specific to each logging type.

How Logging Occurs

For each enabled logging destination, statement logging occurs as follows:

Statements are logged only when executed interactively. Statements are noninteractive, for example, when read from a file or a pipe. It is also possible to suppress statement logging by using the --batch or --execute option.
Statements are ignored and not logged if they match any pattern in the “ignore” list. This list is described later.
mysql logs each nonignored, nonempty statement line individually.
If a nonignored statement spans multiple lines (not including the terminating delimiter), mysql concatenates the lines to form the complete statement, maps newlines to spaces, and logs the result, plus a delimiter.

Consequently, an input statement that spans multiple lines can be logged twice. Consider this input:

mysql> SELECT
    -> 'Today is'
    -> ,
    -> CURDATE()
    -> ;

In this case, mysql logs the “SELECT”, “'Today is'”, “,”, “CURDATE()”, and “;” lines as it reads them. It also logs the complete statement, after mapping SELECT\n'Today is'\n,\nCURDATE() to SELECT 'Today is' , CURDATE(), plus a delimiter. Thus, these lines appear in logged output:

SELECT
'Today is'
,
CURDATE()
;
SELECT 'Today is' , CURDATE();

mysql ignores for logging purposes statements that match any pattern in the “ignore” list. By default, the pattern list is "*IDENTIFIED*:*PASSWORD*", to ignore statements that refer to passwords. Pattern matching is not case-sensitive. Within patterns, two characters are special:

? matches any single character.
* matches any sequence of zero or more characters.

To specify additional patterns, use the --histignore option or set the MYSQL_HISTIGNORE environment variable. (If both are specified, the option value takes precedence.) The value should be a list of one or more colon-separated patterns, which are appended to the default pattern list.

Patterns specified on the command line might need to be quoted or escaped to prevent your command interpreter from treating them specially. For example, to suppress logging for UPDATE and DELETE statements in addition to statements that refer to passwords, invoke mysql like this:

mysql --histignore="*UPDATE*:*DELETE*"

Controlling the History File

The .mysql_history file 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 6.1.2.1, “End-User Guidelines for Password Security”. Statements in the file are accessible from the mysql client when the up-arrow key is used to recall the history. See Disabling Interactive History.

If you do not want to maintain a history file, first remove .mysql_history if it exists. Then use either of the following techniques to prevent it from being created again:

Set the MYSQL_HISTFILE environment variable to /dev/null. To cause this setting to take effect each time you log in, put it in one of your shell's startup files.
Create .mysql_history as a symbolic link to /dev/null; this need be done only once:
```
ln -s /dev/null $HOME/.mysql_history
```

syslog Logging Characteristics

If the --syslog option is given, mysql writes interactive statements to the system logging facility. Message logging has the following characteristics.

Logging occurs at the “information” level. This corresponds to the LOG_INFO priority for syslog on Unix/Linux syslog capability and to EVENTLOG_INFORMATION_TYPE for the Windows Event Log. Consult your system documentation for configuration of your logging capability.

Message size is limited to 1024 bytes.

Messages consist of the identifier MysqlClient followed by these values:

SYSTEM_USER
The operating system user name (login name) or -- if the user is unknown.
MYSQL_USER
The MySQL user name (specified with the --user option) or -- if the user is unknown.
CONNECTION_ID:
The client connection identifier. This is the same as the CONNECTION_ID() function value within the session.
DB_SERVER
The server host or -- if the host is unknown.
DB
The default database or -- if no database has been selected.
QUERY
The text of the logged statement.

Here is a sample of output generated on Linux by using --syslog. This output is formatted for readability; each logged message actually takes a single line.

Mar  7 12:39:25 myhost MysqlClient[20824]:
  SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23,
  DB_SERVER:'127.0.0.1', DB:'--', QUERY:'USE test;'
Mar  7 12:39:28 myhost MysqlClient[20824]:
  SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23,
  DB_SERVER:'127.0.0.1', DB:'test', QUERY:'SHOW TABLES;'

4.5.1.4 mysql Client 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 5.1.17, “Server-Side Help Support”).

If there is no match for the search string, the search fails:

mysql> help me

Nothing found
Please try to run 'help contents' for a list of all accessible topics

Use help contents to see a list of the help categories:

mysql> help contents
You asked for help about help category: "Contents"
For more information, type 'help <item>', where <item> is one of the
following categories:
   Account Management
   Administration
   Data Definition
   Data Manipulation
   Data Types
   Functions
   Functions and Modifiers for Use with GROUP BY
   Geographic Features
   Language Structure
   Plugins
   Storage Engines
   Stored Routines
   Table Maintenance
   Transactions
   Triggers

If the search string matches multiple items, mysql shows a list of matching topics:

mysql> help logs
Many help items for your request exist.
To make a more specific request, please type 'help <item>',
where <item> is one of the following topics:
   SHOW
   SHOW BINARY LOGS
   SHOW ENGINE
   SHOW LOGS

Use a topic as the search string to see the help entry for that topic:

mysql> help show binary logs
Name: 'SHOW BINARY LOGS'
Description:
Syntax:
SHOW BINARY LOGS
SHOW MASTER LOGS

Lists the binary log files on the server. This statement is used as
part of the procedure described in [purge-binary-logs], that shows how
to determine which logs can be purged.

mysql> SHOW BINARY LOGS;
+---------------+-----------+-----------+
| Log_name      | File_size | Encrypted |
+---------------+-----------+-----------+
| binlog.000015 |    724935 | Yes       |
| binlog.000016 |    733481 | Yes       |
+---------------+-----------+-----------+

The search string can contain the wildcard characters % and _. These have the same meaning as for pattern-matching operations performed with the LIKE operator. For example, HELP rep% returns a list of topics that begin with rep:

mysql> HELP rep%
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:
   REPAIR TABLE
   REPEAT FUNCTION
   REPEAT LOOP
   REPLACE
   REPLACE FUNCTION

4.5.1.5 Executing SQL Statements from a Text File

The mysql client typically is used interactively, like this:

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:

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:

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 Client Tips

This section provides information about techniques for more effective use of mysql and about mysql operational behavior.

Input-Line Editing

mysql supports input-line editing, which enables you to modify the current input line in place or recall previous input lines. For example, the left-arrow and right-arrow keys move horizontally within the current input line, and the up-arrow and down-arrow keys move up and down through the set of previously entered lines. Backspace deletes the character before the cursor and typing new characters enters them at the cursor position. To enter the line, press Enter.

On Windows, the editing key sequences are the same as supported for command editing in console windows. On Unix, the key sequences depend on the input library used to build mysql (for example, the libedit or readline library).

Documentation for the libedit and readline libraries is available online. To change the set of key sequences permitted by a given input library, define key bindings in the library startup file. This is a file in your home directory: .editrc for libedit and .inputrc for readline.

For example, in libedit, Control+W deletes everything before the current cursor position and Control+U deletes the entire line. In readline, Control+W deletes the word before the cursor and Control+U deletes everything before the current cursor position. If mysql was built using libedit, a user who prefers the readline behavior for these two keys can put the following lines in the .editrc file (creating the file if necessary):

bind "^W" ed-delete-prev-word
bind "^U" vi-kill-line-prev

To see the current set of key bindings, temporarily put a line that says only bind at the end of .editrc. mysql shows the bindings when it starts.

Disabling Interactive History

The up-arrow key enables you to recall input lines from current and previous sessions. In cases where a console is shared, this behavior may be unsuitable. mysql supports disabling the interactive history partially or fully, depending on the host platform.

On Windows, the history is stored in memory. Alt+F7 deletes all input lines stored in memory for the current history buffer. It also deletes the list of sequential numbers in front of the input lines displayed with F7 and recalled (by number) with F9. New input lines entered after you press Alt+F7 repopulate the current history buffer. Clearing the buffer does not prevent logging to the Windows Event Viewer, if the --syslog option was used to start mysql. Closing the console window also clears the current history buffer.

To disable interactive history on Unix, first delete the .mysql_history file, if it exists (previous entries are recalled otherwise). Then start mysql with the --histignore="*" option to ignore all new input lines. To re-enable the recall (and logging) behavior, restart mysql without the option.

If you prevent the .mysql_history file from being created (see Controlling the History File) and use --histignore="*" to start the mysql client, the interactive history recall facility is disabled fully. Alternatively, if you omit the --histignore option, you can recall the input lines entered during the current session.

Unicode Support on Windows

Windows provides APIs based on UTF-16LE for reading from and writing to the console; the mysql client for Windows is able to use these APIs. The Windows installer creates an item in the MySQL menu named MySQL command line client - Unicode. This item invokes the mysql client with properties set to communicate through the console to the MySQL server using Unicode.

To take advantage of this support manually, run mysql within a console that uses a compatible Unicode font and set the default character set to a Unicode character set that is supported for communication with the server:

Open a console window.
Go to the console window properties, select the font tab, and choose Lucida Console or some other compatible Unicode font. This is necessary because console windows start by default using a DOS raster font that is inadequate for Unicode.
Execute mysql.exe with the --default-character-set=utf8 (or utf8mb4) option. This option is necessary because utf16le is one of the character sets that cannot be used as the client character set. See Impermissible Client Character Sets.

With those changes, mysql uses the Windows APIs to communicate with the console using UTF-16LE, and communicate with the server using UTF-8. (The menu item mentioned previously sets the font and character set as just described.)

To avoid those steps each time you run mysql, you can create a shortcut that invokes mysql.exe. The shortcut should set the console font to Lucida Console or some other compatible Unicode font, and pass the --default-character-set=utf8 (or utf8mb4) option to mysql.exe.

Alternatively, create a shortcut that only sets the console font, and set the character set in the [mysql] group of your my.ini file:

[mysql]
default-character-set=utf8

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: Jones
    reply: jones@example.com
  mail_to: "John Smith" <smith@example.com>
      sbj: UTF-8
      txt: >>>>> "John" == John Smith writes:

John> Hi.  I think this is a good idea.  Is anyone familiar
John> with UTF-8 or Unicode? Otherwise, I'll put this on my
John> TODO list and see what happens.

Yes, please do that.

Regards,
Jones
     file: inbox-jani-1
     hash: 190402944
1 row in set (0.09 sec)

Using Safe-Updates Mode (--safe-updates)

For beginners, a useful startup option is --safe-updates (or --i-am-a-dummy, which has the same effect). Safe-updates mode is helpful for cases when you might have issued an UPDATE or DELETE statement but forgotten the WHERE clause indicating which rows to modify. Normally, such statements update or delete all rows in the table. With --safe-updates, you can modify rows only by specifying the key values that identify them, or a LIMIT clause, or both. This helps prevent accidents. Safe-updates mode also restricts SELECT statements that produce (or are estimated to produce) very large result sets.

The --safe-updates option causes mysql to execute the following statement when it connects to the MySQL server, to set the session values of the sql_safe_updates, sql_select_limit, and max_join_size system variables:

SET sql_safe_updates=1, sql_select_limit=1000, max_join_size=1000000;

The SET statement affects statement processing as follows:

Enabling sql_safe_updates causes UPDATE and DELETE statements to produce an error if they do not 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;
```
Setting sql_select_limit to 1,000 causes the server to limit all SELECT result sets to 1,000 rows unless the statement includes a LIMIT clause.
Setting max_join_size to 1,000,000 causes multiple-table SELECT statements to produce an error if the server estimates it must examine more than 1,000,000 row combinations.

To specify result set limits different from 1,000 and 1,000,000, you can override the defaults by using the --select-limit and --max-join-size options when you invoke mysql:

mysql --safe-updates --select-limit=500 --max-join-size=10000

It is possible for UPDATE and DELETE statements to produce an error in safe-updates mode even with a key specified in the WHERE clause, if the optimizer decides not to use the index on the key column:

Range access on the index cannot be used if memory usage exceeds that permitted by the range_optimizer_max_mem_size system variable. The optimizer then falls back to a table scan. See Limiting Memory Use for Range Optimization.
If key comparisons require type conversion, the index may not be used (see Section 8.3.1, “How MySQL Uses Indexes”). Suppose that an indexed string column c1 is compared to a numeric value using WHERE c1 = 2222. For such comparisons, the string value is converted to a number and the operands are compared numerically (see Section 12.3, “Type Conversion in Expression Evaluation”), preventing use of the index. If safe-updates mode is enabled, an error occurs.

As of MySQL 8.0.13, safe-updates mode also includes these behaviors:

EXPLAIN with UPDATE and DELETE statements does not produce safe-updates errors. This enables use of EXPLAIN plus SHOW WARNINGS to see why an index is not used, which can be helpful in cases such as when a range_optimizer_max_mem_size violation or type conversion occurs and the optimizer does not use an index even though a key column was specified in the WHERE clause.
When a safe-updates error occurs, the error message includes the first diagnostic that was produced, to provide information about the reason for failure. For example, the message may indicate that the range_optimizer_max_mem_size value was exceeded or type conversion occurred, either of which can preclude use of an index.
For multiple-table deletes and updates, an error is produced with safe updates enabled only if any target table uses a table scan.

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 C API Automatic Reconnection Control.

mysql Client Parser Versus Server Parser

The mysql client uses a parser on the client side that is not a duplicate of the complete parser used by the mysqld server on the server side. This can lead to differences in treatment of certain constructs. Examples:

The server parser treats strings delimited by " characters as identifiers rather than as plain strings if the ANSI_QUOTES SQL mode is enabled.
The mysql client parser does not take the ANSI_QUOTES SQL mode into account. It treats strings delimited by ", ', and ` characters the same, regardless of whether ANSI_QUOTES is enabled.
Within /*! ... */ and /*+ ... */ comments, the mysql client parser interprets short-form mysql commands. The server parser does not interpret them because these commands have no meaning on the server side.
If it is desirable for mysql not to interpret short-form commands within comments, a partial workaround is to use the --binary-mode option, which causes all mysql commands to be disabled except \C and \d in noninteractive mode (for input piped to mysql or loaded using the source command).

4.5.2 mysqladmin — A MySQL Server Administration Program

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:

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
Prior to MySQL 8.0.20, tell the server to write debug information to the error log. The connected user must have the SUPER privilege. Format and content of this information is subject to change.
This includes information about the Event Scheduler. See Section 25.4.5, “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. See Section 5.1.12.3, “DNS Lookups and the Host Cache”.
flush-logs [log_type ...]
Flush all logs.
The mysqladmin flush-logs command permits optional log types to be given, to specify which logs to flush. Following the flush-logs command, you can provide a space-separated list of one or more of the following log types: binary, engine, error, general, relay, slow. These correspond to the log types that can be specified for the FLUSH LOGS SQL statement.
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.
To kill threads belonging to other users, the connected user must have the CONNECTION_ADMIN privilege (or the deprecated SUPER privilege).
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 must specify the new password.

Warning

Setting a password using mysqladmin should be considered insecure. On some systems, your password becomes visible to system status programs such as ps that may be invoked by other users to display command lines. MySQL clients typically overwrite the command-line password argument with zeros during their initialization sequence. However, there is still a brief interval during which the value is visible. Also, on some systems this overwriting strategy is ineffective and the password remains visible to ps. (SystemV Unix systems and perhaps others are subject to this problem.)

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:
```
mysqladmin password "my new password"
```
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 is 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 13.7.7.29, “SHOW PROCESSLIST Statement”.)
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 replica server.
status
Display a short server status message.
stop-slave
Stop replication on a replica 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 | jones | 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 5.4.5, “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.

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. For information about option files used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.

Table 4.12 mysqladmin Options

Option Name	Description	Introduced	Deprecated
--bind-address	Use specified network interface to connect to MySQL Server
--compress	Compress all information sent between client and server		8.0.18
--compression-algorithms	Permitted compression algorithms for connections to server	8.0.18
--connect-timeout	Number of seconds before connection timeout
--count	Number of iterations to make for repeated command execution
--debug	Write debugging log
--debug-check	Print debugging information when program exits
--debug-info	Print debugging information, memory, and CPU statistics when program exits
--default-auth	Authentication plugin to use
--default-character-set	Specify default character set
--defaults-extra-file	Read named option file in addition to usual option files
--defaults-file	Read only named option file
--defaults-group-suffix	Option group suffix value
--enable-cleartext-plugin	Enable cleartext authentication plugin
--force	Continue even if an SQL error occurs
--get-server-public-key	Request RSA public key from server
--help	Display help message and exit
--host	Host on which MySQL server is located
--login-path	Read login path options from .mylogin.cnf
--no-beep	Do not beep when errors occur
--no-defaults	Read no option files
--password	Password to use when connecting to server
--pipe	Connect to server using named pipe (Windows only)
--plugin-dir	Directory where plugins are installed
--port	TCP/IP port number for connection
--print-defaults	Print default options
--protocol	Transport protocol to use
--relative	Show the difference between the current and previous values when used with the --sleep option
--server-public-key-path	Path name to file containing RSA public key
--shared-memory-base-name	Shared-memory name for shared-memory connections (Windows only)
--show-warnings	Show warnings after statement execution
--shutdown-timeout	The maximum number of seconds to wait for server shutdown
--silent	Silent mode
--sleep	Execute commands repeatedly, sleeping for delay seconds in between
--socket	Unix socket file or Windows named pipe to use
--ssl-ca	File that contains list of trusted SSL Certificate Authorities
--ssl-capath	Directory that contains trusted SSL Certificate Authority certificate files
--ssl-cert	File that contains X.509 certificate
--ssl-cipher	Permissible ciphers for connection encryption
--ssl-crl	File that contains certificate revocation lists
--ssl-crlpath	Directory that contains certificate revocation-list files
--ssl-fips-mode	Whether to enable FIPS mode on client side
--ssl-key	File that contains X.509 key
--ssl-mode	Desired security state of connection to server
--tls-ciphersuites	Permissible TLSv1.3 ciphersuites for encrypted connections	8.0.16
--tls-version	Permissible TLS protocols for encrypted connections
--user	MySQL user name to use when connecting to server
--verbose	Verbose mode
--version	Display version information and exit
--vertical	Print query output rows vertically (one line per column value)
--wait	If the connection cannot be established, wait and retry instead of aborting
--zstd-compression-level	Compression level for connections to server that use zstd compression	8.0.18

--help, -?
Display a help message and exit.
--bind-address=ip_address
On a computer having multiple network interfaces, use this option to select which interface to use for connecting to the MySQL server.
--character-sets-dir=dir_name
The directory where character sets are installed. See Section 10.15, “Character Set Configuration”.
--compress, -C
Compress all information sent between the client and the server if possible. See Section 4.2.8, “Connection Compression Control”.
As of MySQL 8.0.18, this option is deprecated. Expect it to be removed in a future version of MySQL. See Configuring Legacy Connection Compression.
--compression-algorithms=value
The permitted compression algorithms for connections to the server. The available algorithms are the same as for the protocol_compression_algorithms system variable. The default value is uncompressed.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.
--connect-timeout=value
The maximum number of seconds before connection timeout. The default value is 43200 (12 hours).
--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.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--debug-check
Print some debugging information when the program exits.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--debug-info
Print debugging information and memory and CPU usage statistics when the program exits.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--default-auth=plugin
A hint about which client-side authentication plugin to use. See Section 6.2.17, “Pluggable Authentication”.
--default-character-set=charset_name
Use charset_name as the default character set. See Section 10.15, “Character Set Configuration”.
--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, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-file=file_name
Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
Exception: Even with --defaults-file, client programs read .mylogin.cnf.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-group-suffix=str
Read not only the usual option groups, but also groups with the usual names and a suffix of str. For example, mysqladmin normally reads the [client] and [mysqladmin] groups. If this option is given as --defaults-group-suffix=_other, mysqladmin also reads the [client_other] and [mysqladmin_other] groups.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--enable-cleartext-plugin
Enable the mysql_clear_password cleartext authentication plugin. (See Section 6.4.1.4, “Client-Side Cleartext Pluggable Authentication”.)
--force, -f
Do not ask for confirmation for the drop db_name command. With multiple commands, continue even if an error occurs.
--get-server-public-key
Request from the server the public key required for RSA key pair-based password exchange. This option applies to clients that authenticate with the caching_sha2_password authentication plugin. For that plugin, the server does not send the public key unless requested. This option is ignored for accounts that do not authenticate with that plugin. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For information about the caching_sha2_password plugin, see Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--host=host_name, -h host_name
Connect to the MySQL server on the given host.
--login-path=name
Read options from the named login path in the .mylogin.cnf login path file. A “login path” is an option group containing options that specify which MySQL server to connect to and which account to authenticate as. To create or modify a login path file, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--no-beep, -b
Suppress the warning beep that is emitted by default for errors such as a failure to connect to the server.
--no-defaults
Do not read any option files. If program startup fails due to reading unknown options from an option file, --no-defaults can be used to prevent them from being read.
The exception is that the .mylogin.cnf file is read in all cases, if it exists. This permits passwords to be specified in a safer way than on the command line even when --no-defaults is used. To create .mylogin.cnf, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--password[=password], -p[password]
The password of the MySQL account used for connecting to the server. The password value is optional. If not given, mysqladmin prompts for one. If given, there must be no space between --password= or -p and the password following it. If no password option is specified, the default is to send no password.
Specifying a password on the command line should be considered insecure. To avoid giving the password on the command line, use an option file. See Section 6.1.2.1, “End-User Guidelines for Password Security”.
To explicitly specify that there is no password and that mysqladmin should not prompt for one, use the --skip-password option.
--pipe, -W
On Windows, connect to the server using a named pipe. This option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--plugin-dir=dir_name
The directory in which to look for plugins. Specify this option if the --default-auth option is used to specify an authentication plugin but mysqladmin does not find it. See Section 6.2.17, “Pluggable Authentication”.
--port=port_num, -P port_num
For TCP/IP connections, the port number to use.
--print-defaults
Print the program name and all options that it gets from option files.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The transport protocol to use for connecting to the server. It is useful when the other connection parameters normally result in use of a protocol other than the one you want. For details on the permissible values, see Section 4.2.7, “Connection Transport Protocols”.
--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.
--server-public-key-path=file_name
The path name to a file in PEM format containing a client-side copy of the public key required by the server for RSA key pair-based password exchange. This option applies to clients that authenticate with the sha256_password or caching_sha2_password authentication plugin. This option is ignored for accounts that do not authenticate with one of those plugins. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For sha256_password, this option applies only if MySQL was built using OpenSSL.
For information about the sha256_password and caching_sha2_password plugins, see Section 6.4.1.3, “SHA-256 Pluggable Authentication”, and Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--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.
This option applies only if the server was started with the shared_memory system variable enabled to support shared-memory connections.
--show-warnings
Show warnings resulting from execution of statements sent to the server.
--shutdown-timeout=value
The maximum number of seconds to wait for server shutdown. The default value is 3600 (1 hour).
--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.
On Windows, this option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--ssl*
Options that begin with --ssl specify whether to connect to the server using encryption and indicate where to find SSL keys and certificates. See Command Options for Encrypted Connections.
--ssl-fips-mode={OFF|ON|STRICT}
Controls whether to enable FIPS mode on the client side. The --ssl-fips-mode option differs from other --ssl-xxx options in that it is not used to establish encrypted connections, but rather to affect which cryptographic operations to permit. See Section 6.8, “FIPS Support”.
These --ssl-fips-mode values are permitted:
- OFF: Disable FIPS mode.
- ON: Enable FIPS mode.
- STRICT: Enable “strict” FIPS mode.
Note

If the OpenSSL FIPS Object Module is not available, the only permitted value for --ssl-fips-mode is OFF. In this case, setting --ssl-fips-mode to ON or STRICT causes the client to produce a warning at startup and to operate in non-FIPS mode.
--tls-ciphersuites=ciphersuite_list
The permissible ciphersuites for encrypted connections that use TLSv1.3. The value is a list of one or more colon-separated ciphersuite names. The ciphersuites that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
This option was added in MySQL 8.0.16.
--tls-version=protocol_list
The permissible TLS protocols for encrypted connections. The value is a list of one or more comma-separated protocol names. The protocols that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
--user=user_name, -u user_name
The user name of the MySQL account to use for 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.
--zstd-compression-level=level
The compression level to use for connections to the server that use the zstd compression algorithm. The permitted levels are from 1 to 22, with larger values indicating increasing levels of compression. The default zstd compression level is 3. The compression level setting has no effect on connections that do not use zstd compression.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.

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 13.3.6, “LOCK TABLES and UNLOCK TABLES Statements”, 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 the MySQL upgrade procedure if it determines that table checking is needed because it processes tables the same way.)

mysqlcheck must be used when the mysqld server is running, which means 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 13.7.3, “Table Maintenance Statements”.

All storage engines do not necessarily support all four maintenance operations. In such cases, an error message is displayed. For example, if test.t is an 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 2.11.13, “Rebuilding or Repairing Tables or Indexes” for manual table repair strategies. This is 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:

mysqlcheck [options] db_name [tbl_name ...]
mysqlcheck [options] --databases db_name ...
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.

Command	Meaning
mysqlrepair	The default option is `--repair`
mysqlanalyze	The default option is `--analyze`
mysqloptimize	The 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. For information about option files used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.

Table 4.13 mysqlcheck Options

Option Name	Description	Introduced	Deprecated
--all-databases	Check all tables in all databases
--all-in-1	Execute a single statement for each database that names all the tables from that database
--analyze	Analyze the tables
--auto-repair	If a checked table is corrupted, automatically fix it
--bind-address	Use specified network interface to connect to MySQL Server
--character-sets-dir	Directory where character sets are installed
--check	Check the tables for errors
--check-only-changed	Check only tables that have changed since the last check
--check-upgrade	Invoke CHECK TABLE with the FOR UPGRADE option
--compress	Compress all information sent between client and server		8.0.18
--compression-algorithms	Permitted compression algorithms for connections to server	8.0.18
--databases	Interpret all arguments as database names
--debug	Write debugging log
--debug-check	Print debugging information when program exits
--debug-info	Print debugging information, memory, and CPU statistics when program exits
--default-auth	Authentication plugin to use
--default-character-set	Specify default character set
--defaults-extra-file	Read named option file in addition to usual option files
--defaults-file	Read only named option file
--defaults-group-suffix	Option group suffix value
--enable-cleartext-plugin	Enable cleartext authentication plugin
--extended	Check and repair tables
--fast	Check only tables that have not been closed properly
--force	Continue even if an SQL error occurs
--get-server-public-key	Request RSA public key from server
--help	Display help message and exit
--host	Host on which MySQL server is located
--login-path	Read login path options from .mylogin.cnf
--medium-check	Do a check that is faster than an --extended operation
--no-defaults	Read no option files
--optimize	Optimize the tables
--password	Password to use when connecting to server
--pipe	Connect to server using named pipe (Windows only)
--plugin-dir	Directory where plugins are installed
--port	TCP/IP port number for connection
--print-defaults	Print default options
--protocol	Transport protocol to use
--quick	The fastest method of checking
--repair	Perform a repair that can fix almost anything except unique keys that are not unique
--server-public-key-path	Path name to file containing RSA public key
--shared-memory-base-name	Shared-memory name for shared-memory connections (Windows only)
--silent	Silent mode
--skip-database	Omit this database from performed operations
--socket	Unix socket file or Windows named pipe to use
--ssl-ca	File that contains list of trusted SSL Certificate Authorities
--ssl-capath	Directory that contains trusted SSL Certificate Authority certificate files
--ssl-cert	File that contains X.509 certificate
--ssl-cipher	Permissible ciphers for connection encryption
--ssl-crl	File that contains certificate revocation lists
--ssl-crlpath	Directory that contains certificate revocation-list files
--ssl-fips-mode	Whether to enable FIPS mode on client side
--ssl-key	File that contains X.509 key
--ssl-mode	Desired security state of connection to server
--tables	Overrides the --databases or -B option
--tls-ciphersuites	Permissible TLSv1.3 ciphersuites for encrypted connections	8.0.16
--tls-version	Permissible TLS protocols for encrypted connections
--use-frm	For repair operations on MyISAM tables
--user	MySQL user name to use when connecting to server
--verbose	Verbose mode
--version	Display version information and exit
--write-binlog	Log ANALYZE, OPTIMIZE, REPAIR statements to binary log. --skip-write-binlog adds NO_WRITE_TO_BINLOG to these statements
--zstd-compression-level	Compression level for connections to server that use zstd compression	8.0.18

--help, -?
Display a help message and exit.
--all-databases, -A
Check all tables in all databases. This is the same as using the --databases option and naming all the databases on the command line, except that the INFORMATION_SCHEMA and performance_schema databases are not checked. They can be checked by explicitly naming them with the --databases option.
--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, use this option to select which interface to use for connecting to the MySQL server.
--character-sets-dir=dir_name
The directory where character sets are installed. See Section 10.15, “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.
--compress
Compress all information sent between the client and the server if possible. See Section 4.2.8, “Connection Compression Control”.
As of MySQL 8.0.18, this option is deprecated. Expect it to be removed in a future version of MySQL. See Configuring Legacy Connection Compression.
--compression-algorithms=value
The permitted compression algorithms for connections to the server. The available algorithms are the same as for the protocol_compression_algorithms system variable. The default value is uncompressed.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.
--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 any 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.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--debug-check
Print some debugging information when the program exits.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--debug-info
Print debugging information and memory and CPU usage statistics when the program exits.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--default-character-set=charset_name
Use charset_name as the default character set. See Section 10.15, “Character Set Configuration”.
--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, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-file=file_name
Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
Exception: Even with --defaults-file, client programs read .mylogin.cnf.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-group-suffix=str
Read not only the usual option groups, but also groups with the usual names and a suffix of str. For example, mysqlcheck normally reads the [client] and [mysqlcheck] groups. If this option is given as --defaults-group-suffix=_other, mysqlcheck also reads the [client_other] and [mysqlcheck_other] groups.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--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
A hint about which client-side authentication plugin to use. See Section 6.2.17, “Pluggable Authentication”.
--enable-cleartext-plugin
Enable the mysql_clear_password cleartext authentication plugin. (See Section 6.4.1.4, “Client-Side Cleartext Pluggable Authentication”.)
--fast, -F
Check only tables that have not been closed properly.
--force, -f
Continue even if an SQL error occurs.
--get-server-public-key
Request from the server the public key required for RSA key pair-based password exchange. This option applies to clients that authenticate with the caching_sha2_password authentication plugin. For that plugin, the server does not send the public key unless requested. This option is ignored for accounts that do not authenticate with that plugin. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For information about the caching_sha2_password plugin, see Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--host=host_name, -h host_name
Connect to the MySQL server on the given host.
--login-path=name
Read options from the named login path in the .mylogin.cnf login path file. A “login path” is an option group containing options that specify which MySQL server to connect to and which account to authenticate as. To create or modify a login path file, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--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.
--no-defaults
Do not read any option files. If program startup fails due to reading unknown options from an option file, --no-defaults can be used to prevent them from being read.
The exception is that the .mylogin.cnf file is read in all cases, if it exists. This permits passwords to be specified in a safer way than on the command line even when --no-defaults is used. To create .mylogin.cnf, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--optimize, -o
Optimize the tables.
--password[=password], -p[password]
The password of the MySQL account used for connecting to the server. The password value is optional. If not given, mysqlcheck prompts for one. If given, there must be no space between --password= or -p and the password following it. If no password option is specified, the default is to send no password.
Specifying a password on the command line should be considered insecure. To avoid giving the password on the command line, use an option file. See Section 6.1.2.1, “End-User Guidelines for Password Security”.
To explicitly specify that there is no password and that mysqlcheck should not prompt for one, use the --skip-password option.
--pipe, -W
On Windows, connect to the server using a named pipe. This option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--plugin-dir=dir_name
The directory in which to look for plugins. Specify this option if the --default-auth option is used to specify an authentication plugin but mysqlcheck does not find it. See Section 6.2.17, “Pluggable Authentication”.
--port=port_num, -P port_num
For TCP/IP connections, the port number to use.
--print-defaults
Print the program name and all options that it gets from option files.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The transport protocol to use for connecting to the server. It is useful when the other connection parameters normally result in use of a protocol other than the one you want. For details on the permissible values, see Section 4.2.7, “Connection Transport Protocols”.
--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.
--server-public-key-path=file_name
The path name to a file in PEM format containing a client-side copy of the public key required by the server for RSA key pair-based password exchange. This option applies to clients that authenticate with the sha256_password or caching_sha2_password authentication plugin. This option is ignored for accounts that do not authenticate with one of those plugins. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For sha256_password, this option applies only if MySQL was built using OpenSSL.
For information about the sha256_password and caching_sha2_password plugins, see Section 6.4.1.3, “SHA-256 Pluggable Authentication”, and Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--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.
This option applies only if the server was started with the shared_memory system variable enabled to support shared-memory connections.
--silent, -s
Silent mode. Print only error messages.
--skip-database=db_name
Do not include the named database (case-sensitive) in the operations performed by mysqlcheck.
--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.
On Windows, this option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--ssl*
Options that begin with --ssl specify whether to connect to the server using encryption and indicate where to find SSL keys and certificates. See Command Options for Encrypted Connections.
--ssl-fips-mode={OFF|ON|STRICT}
Controls whether to enable FIPS mode on the client side. The --ssl-fips-mode option differs from other --ssl-xxx options in that it is not used to establish encrypted connections, but rather to affect which cryptographic operations to permit. See Section 6.8, “FIPS Support”.
These --ssl-fips-mode values are permitted:
- OFF: Disable FIPS mode.
- ON: Enable FIPS mode.
- STRICT: Enable “strict” FIPS mode.
Note

If the OpenSSL FIPS Object Module is not available, the only permitted value for --ssl-fips-mode is OFF. In this case, setting --ssl-fips-mode to ON or STRICT causes the client to produce a warning at startup and to operate in non-FIPS mode.
--tables
Override the --databases or -B option. All name arguments following the option are regarded as table names.
--tls-ciphersuites=ciphersuite_list
The permissible ciphersuites for encrypted connections that use TLSv1.3. The value is a list of one or more colon-separated ciphersuite names. The ciphersuites that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
This option was added in MySQL 8.0.16.
--tls-version=protocol_list
The permissible TLS protocols for encrypted connections. The value is a list of one or more comma-separated protocol names. The protocols that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
--use-frm
For repair operations on MyISAM tables, get the table structure from the data dictionary so that the table can be repaired even if the .MYI header is corrupted.
--user=user_name, -u user_name
The user name of the MySQL account to use for 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 replicas or run when using the binary logs for recovery from backup.
--zstd-compression-level=level
The compression level to use for connections to the server that use the zstd compression algorithm. The permitted levels are from 1 to 22, with larger values indicating increasing levels of compression. The default zstd compression level is 3. The compression level setting has no effect on connections that do not use zstd compression.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.

4.5.4 mysqldump — A Database Backup Program

The mysqldump client utility performs logical backups, producing a set of SQL statements that can be executed to reproduce the original database object definitions and table data. It dumps one or more MySQL databases for backup or transfer to another SQL server. The mysqldump command can also generate output in CSV, other delimited text, or XML format.

Tip

Consider using the MySQL Shell dump utilities, which provide parallel dumping with multiple threads, file compression, and progress information display, as well as cloud features such as Oracle Cloud Infrastructure Object Storage streaming, and MySQL Database Service compatibility checks and modifications. Dumps can be easily imported into a MySQL Server instance or a MySQL Database Service DB System using the MySQL Shell load dump utilities. Installation instructions for MySQL Shell can be found here.

mysqldump requires at least the SELECT privilege for dumped tables, SHOW VIEW for dumped views, TRIGGER for dumped triggers, LOCK TABLES if the --single-transaction option is not used, and (as of MySQL 8.0.21) PROCESS if the --no-tablespaces option is not used. Certain options might require other privileges as noted in the option descriptions.

To reload a dump file, you must have the privileges required to execute the statements that it contains, such as the appropriate CREATE privileges for objects created by those statements.

mysqldump output can include ALTER DATABASE statements that change the database collation. These may be used when dumping stored programs to preserve their character encodings. To reload a dump file containing such statements, the ALTER privilege for the affected database is required.

Note

A dump made using PowerShell on Windows with output redirection creates a file that has UTF-16 encoding:

mysqldump [options] > dump.sql

However, UTF-16 is not permitted as a connection character set (see Impermissible Client Character Sets), so the dump file cannot be loaded correctly. To work around this issue, use the --result-file option, which creates the output in ASCII format:

mysqldump [options] --result-file=dump.sql

Performance and Scalability Considerations

mysqldump advantages include the convenience and flexibility of viewing or even editing the output before restoring. You can clone databases for development and DBA work, or produce slight variations of an existing database for testing. It is not intended as a fast or scalable solution for backing up substantial amounts of data. With large data sizes, even if the backup step takes a reasonable time, restoring the data can be very slow because replaying the SQL statements involves disk I/O for insertion, index creation, and so on.

For large-scale backup and restore, a physical backup is more appropriate, to copy the data files in their original format that can be restored quickly:

If your tables are primarily InnoDB tables, or if you have a mix of InnoDB and MyISAM tables, consider using the mysqlbackup command of the MySQL Enterprise Backup product. (Available as part of the Enterprise subscription.) It provides the best performance for InnoDB backups with minimal disruption; it can also back up tables from MyISAM and other storage engines; and it provides a number of convenient options to accommodate different backup scenarios. See Section 30.2, “MySQL Enterprise Backup Overview”.

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, use the --skip-opt option instead of the --opt or --extended-insert option.

For additional information about mysqldump, see Section 7.4, “Using mysqldump for Backups”.

Invocation Syntax

There are in general three ways to use mysqldump—in order to dump a set of one or more tables, a set of one or more complete databases, or an entire MySQL server—as shown here:

mysqldump [options] db_name [tbl_name ...]
mysqldump [options] --databases db_name ...
mysqldump [options] --all-databases

To dump entire databases, do not name any tables following db_name, or use the --databases or --all-databases option.

To see a list of the options your version of mysqldump supports, issue the command mysqldump --help.

Option Syntax - Alphabetical Summary

mysqldump supports the following options, which can be specified on the command line or in the [mysqldump] and [client] groups of an option file. For information about option files used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.

Table 4.14 mysqldump Options

Option Name	Description	Introduced	Deprecated
--add-drop-database	Add DROP DATABASE statement before each CREATE DATABASE statement
--add-drop-table	Add DROP TABLE statement before each CREATE TABLE statement
--add-drop-trigger	Add DROP TRIGGER statement before each CREATE TRIGGER statement
--add-locks	Surround each table dump with LOCK TABLES and UNLOCK TABLES statements
--all-databases	Dump all tables in all databases
--allow-keywords	Allow creation of column names that are keywords
--apply-slave-statements	Include STOP SLAVE prior to CHANGE MASTER statement and START SLAVE at end of output
--bind-address	Use specified network interface to connect to MySQL Server
--character-sets-dir	Directory where character sets are installed
--column-statistics	Write ANALYZE TABLE statements to generate statistics histograms
--comments	Add comments to dump file
--compact	Produce more compact output
--compatible	Produce output that is more compatible with other database systems or with older MySQL servers
--complete-insert	Use complete INSERT statements that include column names
--compress	Compress all information sent between client and server		8.0.18
--compression-algorithms	Permitted compression algorithms for connections to server	8.0.18
--create-options	Include all MySQL-specific table options in CREATE TABLE statements
--databases	Interpret all name arguments as database names
--debug	Write debugging log
--debug-check	Print debugging information when program exits
--debug-info	Print debugging information, memory, and CPU statistics when program exits
--default-auth	Authentication plugin to use
--default-character-set	Specify default character set
--defaults-extra-file	Read named option file in addition to usual option files
--defaults-file	Read only named option file
--defaults-group-suffix	Option group suffix value
--delete-master-logs	On a master replication server, delete the binary logs after performing the dump operation
--disable-keys	For each table, surround INSERT statements with statements to disable and enable keys
--dump-date	Include dump date as "Dump completed on" comment if --comments is given
--dump-slave	Include CHANGE MASTER statement that lists binary log coordinates of slave's master
--enable-cleartext-plugin	Enable cleartext authentication plugin
--events	Dump events from dumped databases
--extended-insert	Use multiple-row INSERT syntax
--fields-enclosed-by	This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA
--fields-escaped-by	This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA
--fields-optionally-enclosed-by	This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA
--fields-terminated-by	This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA
--flush-logs	Flush MySQL server log files before starting dump
--flush-privileges	Emit a FLUSH PRIVILEGES statement after dumping mysql database
--force	Continue even if an SQL error occurs during a table dump
--get-server-public-key	Request RSA public key from server
--help	Display help message and exit
--hex-blob	Dump binary columns using hexadecimal notation
--host	Host on which MySQL server is located
--ignore-error	Ignore specified errors
--ignore-table	Do not dump given table
--include-master-host-port	Include MASTER_HOST/MASTER_PORT options in CHANGE MASTER statement produced with --dump-slave
--insert-ignore	Write INSERT IGNORE rather than INSERT statements
--lines-terminated-by	This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA
--lock-all-tables	Lock all tables across all databases
--lock-tables	Lock all tables before dumping them
--log-error	Append warnings and errors to named file
--login-path	Read login path options from .mylogin.cnf
--master-data	Write the binary log file name and position to the output
--max-allowed-packet	Maximum packet length to send to or receive from server
--net-buffer-length	Buffer size for TCP/IP and socket communication
--network-timeout	Increase network timeouts to permit larger table dumps
--no-autocommit	Enclose the INSERT statements for each dumped table within SET autocommit = 0 and COMMIT statements
--no-create-db	Do not write CREATE DATABASE statements
--no-create-info	Do not write CREATE TABLE statements that re-create each dumped table
--no-data	Do not dump table contents
--no-defaults	Read no option files
--no-set-names	Same as --skip-set-charset
--no-tablespaces	Do not write any CREATE LOGFILE GROUP or CREATE TABLESPACE statements in output
--opt	Shorthand for --add-drop-table --add-locks --create-options --disable-keys --extended-insert --lock-tables --quick --set-charset
--order-by-primary	Dump each table's rows sorted by its primary key, or by its first unique index
--password	Password to use when connecting to server
--pipe	Connect to server using named pipe (Windows only)
--plugin-dir	Directory where plugins are installed
--port	TCP/IP port number for connection
--print-defaults	Print default options
--protocol	Transport protocol to use
--quick	Retrieve rows for a table from the server a row at a time
--quote-names	Quote identifiers within backtick characters
--replace	Write REPLACE statements rather than INSERT statements
--result-file	Direct output to a given file
--routines	Dump stored routines (procedures and functions) from dumped databases
--server-public-key-path	Path name to file containing RSA public key
--set-charset	Add SET NAMES default_character_set to output
--set-gtid-purged	Whether to add SET @@GLOBAL.GTID_PURGED to output
--shared-memory-base-name	Shared-memory name for shared-memory connections (Windows only)
--show-create-skip-secondary-engine	Exclude SECONDARY ENGINE clause from CREATE TABLE statements	8.0.18
--single-transaction	Issue a BEGIN SQL statement before dumping data from server
--skip-add-drop-table	Do not add a DROP TABLE statement before each CREATE TABLE statement
--skip-add-locks	Do not add locks
--skip-comments	Do not add comments to dump file
--skip-compact	Do not produce more compact output
--skip-disable-keys	Do not disable keys
--skip-extended-insert	Turn off extended-insert
--skip-opt	Turn off options set by --opt
--skip-quick	Do not retrieve rows for a table from the server a row at a time
--skip-quote-names	Do not quote identifiers
--skip-set-charset	Do not write SET NAMES statement
--skip-triggers	Do not dump triggers
--skip-tz-utc	Turn off tz-utc
--socket	Unix socket file or Windows named pipe to use
--ssl-ca	File that contains list of trusted SSL Certificate Authorities
--ssl-capath	Directory that contains trusted SSL Certificate Authority certificate files
--ssl-cert	File that contains X.509 certificate
--ssl-cipher	Permissible ciphers for connection encryption
--ssl-crl	File that contains certificate revocation lists
--ssl-crlpath	Directory that contains certificate revocation-list files
--ssl-fips-mode	Whether to enable FIPS mode on client side
--ssl-key	File that contains X.509 key
--ssl-mode	Desired security state of connection to server
--tab	Produce tab-separated data files
--tables	Override --databases or -B option
--tls-ciphersuites	Permissible TLSv1.3 ciphersuites for encrypted connections	8.0.16
--tls-version	Permissible TLS protocols for encrypted connections
--triggers	Dump triggers for each dumped table
--tz-utc	Add SET TIME_ZONE='+00:00' to dump file
--user	MySQL user name to use when connecting to server
--verbose	Verbose mode
--version	Display version information and exit
--where	Dump only rows selected by given WHERE condition
--xml	Produce XML output
--zstd-compression-level	Compression level for connections to server that use zstd compression	8.0.18

Connection Options

The mysqldump command logs into a MySQL server to extract information. The following options specify how to connect to the MySQL server, either on the same machine or a remote system.

--bind-address=ip_address
On a computer having multiple network interfaces, use this option to select which interface to use for connecting to the MySQL server.
--compress, -C
Compress all information sent between the client and the server if possible. See Section 4.2.8, “Connection Compression Control”.
As of MySQL 8.0.18, this option is deprecated. Expect it to be removed in a future version of MySQL. See Configuring Legacy Connection Compression.
--compression-algorithms=value
The permitted compression algorithms for connections to the server. The available algorithms are the same as for the protocol_compression_algorithms system variable. The default value is uncompressed.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.
--default-auth=plugin
A hint about which client-side authentication plugin to use. See Section 6.2.17, “Pluggable Authentication”.
--enable-cleartext-plugin
Enable the mysql_clear_password cleartext authentication plugin. (See Section 6.4.1.4, “Client-Side Cleartext Pluggable Authentication”.)
--get-server-public-key
Request from the server the public key required for RSA key pair-based password exchange. This option applies to clients that authenticate with the caching_sha2_password authentication plugin. For that plugin, the server does not send the public key unless requested. This option is ignored for accounts that do not authenticate with that plugin. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For information about the caching_sha2_password plugin, see Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--host=host_name, -h host_name
Dump data from the MySQL server on the given host. The default host is localhost.
--login-path=name
Read options from the named login path in the .mylogin.cnf login path file. A “login path” is an option group containing options that specify which MySQL server to connect to and which account to authenticate as. To create or modify a login path file, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--password[=password], -p[password]
The password of the MySQL account used for connecting to the server. The password value is optional. If not given, mysqldump prompts for one. If given, there must be no space between --password= or -p and the password following it. If no password option is specified, the default is to send no password.
Specifying a password on the command line should be considered insecure. To avoid giving the password on the command line, use an option file. See Section 6.1.2.1, “End-User Guidelines for Password Security”.
To explicitly specify that there is no password and that mysqldump should not prompt for one, use the --skip-password option.
--pipe, -W
On Windows, connect to the server using a named pipe. This option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--plugin-dir=dir_name
The directory in which to look for plugins. Specify this option if the --default-auth option is used to specify an authentication plugin but mysqldump does not find it. See Section 6.2.17, “Pluggable Authentication”.
--port=port_num, -P port_num
For TCP/IP connections, the port number to use.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The transport protocol to use for connecting to the server. It is useful when the other connection parameters normally result in use of a protocol other than the one you want. For details on the permissible values, see Section 4.2.7, “Connection Transport Protocols”.
--server-public-key-path=file_name
The path name to a file in PEM format containing a client-side copy of the public key required by the server for RSA key pair-based password exchange. This option applies to clients that authenticate with the sha256_password or caching_sha2_password authentication plugin. This option is ignored for accounts that do not authenticate with one of those plugins. It is also ignored if RSA-based password exchange is not used, as is the case when the client connects to the server using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file, it takes precedence over --get-server-public-key.
For sha256_password, this option applies only if MySQL was built using OpenSSL.
For information about the sha256_password and caching_sha2_password plugins, see Section 6.4.1.3, “SHA-256 Pluggable Authentication”, and Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
--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.
On Windows, this option applies only if the server was started with the named_pipe system variable enabled to support named-pipe connections. In addition, the user making the connection must be a member of the Windows group specified by the named_pipe_full_access_group system variable.
--ssl*
Options that begin with --ssl specify whether to connect to the server using encryption and indicate where to find SSL keys and certificates. See Command Options for Encrypted Connections.
--ssl-fips-mode={OFF|ON|STRICT}
Controls whether to enable FIPS mode on the client side. The --ssl-fips-mode option differs from other --ssl-xxx options in that it is not used to establish encrypted connections, but rather to affect which cryptographic operations to permit. See Section 6.8, “FIPS Support”.
These --ssl-fips-mode values are permitted:
- OFF: Disable FIPS mode.
- ON: Enable FIPS mode.
- STRICT: Enable “strict” FIPS mode.
Note

If the OpenSSL FIPS Object Module is not available, the only permitted value for --ssl-fips-mode is OFF. In this case, setting --ssl-fips-mode to ON or STRICT causes the client to produce a warning at startup and to operate in non-FIPS mode.
--tls-ciphersuites=ciphersuite_list
The permissible ciphersuites for encrypted connections that use TLSv1.3. The value is a list of one or more colon-separated ciphersuite names. The ciphersuites that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
This option was added in MySQL 8.0.16.
--tls-version=protocol_list
The permissible TLS protocols for encrypted connections. The value is a list of one or more comma-separated protocol names. The protocols that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
--user=user_name, -u user_name
The user name of the MySQL account to use for connecting to the server.
--zstd-compression-level=level
The compression level to use for connections to the server that use the zstd compression algorithm. The permitted levels are from 1 to 22, with larger values indicating increasing levels of compression. The default zstd compression level is 3. The compression level setting has no effect on connections that do not use zstd compression.
For more information, see Section 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.

Option-File Options

These options are used to control which option files to read.

--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, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-file=file_name
Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. If file_name is not an absolute path name, it is interpreted relative to the current directory.
Exception: Even with --defaults-file, client programs read .mylogin.cnf.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--defaults-group-suffix=str
Read not only the usual option groups, but also groups with the usual names and a suffix of str. For example, mysqldump normally reads the [client] and [mysqldump] groups. If this option is given as --defaults-group-suffix=_other, mysqldump also reads the [client_other] and [mysqldump_other] groups.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--no-defaults
Do not read any option files. If program startup fails due to reading unknown options from an option file, --no-defaults can be used to prevent them from being read.
The exception is that the .mylogin.cnf file is read in all cases, if it exists. This permits passwords to be specified in a safer way than on the command line even when --no-defaults is used. To create .mylogin.cnf, use the mysql_config_editor utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--print-defaults
Print the program name and all options that it gets from option files.
For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.

DDL Options

Usage scenarios for mysqldump include setting up an entire new MySQL instance (including database tables), and replacing data inside an existing instance with existing databases and tables. The following options let you specify which things to tear down and set up when restoring a dump, by encoding various DDL statements within the dump file.

--add-drop-database
Write 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.

Note

In MySQL 8.0, the mysql schema is considered a system schema that cannot be dropped by end users. If --add-drop-database is used with --all-databases or with --databases where the list of schemas to be dumped includes mysql, the dump file contains a DROP DATABASE `mysql` statement that causes an error when the dump file is reloaded.
Instead, to use --add-drop-database, use --databases with a list of schemas to be dumped, where the list does not include mysql.
--add-drop-table
Write a DROP TABLE statement before each CREATE TABLE statement.
--add-drop-trigger
Write a DROP TRIGGER statement before each CREATE TRIGGER statement.
--all-tablespaces, -Y
Adds to a table dump all SQL statements needed to create any tablespaces used by an NDB table. This information is not otherwise included in the output from mysqldump. This option is currently relevant only to NDB Cluster tables.
--no-create-db, -n
Suppress 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 create each dumped table.

Note

This option does not exclude statements creating log file groups or tablespaces from mysqldump output; however, you can use the --no-tablespaces option for this purpose.
--no-tablespaces, -y
This option suppresses all CREATE LOGFILE GROUP and CREATE TABLESPACE statements in the output of mysqldump.
--replace
Write REPLACE statements rather than INSERT statements.

Debug Options

The following options print debugging information, encode debugging information in the dump file, or let the dump operation proceed regardless of potential problems.

--allow-keywords
Permit creation of column names that are keywords. This works by prefixing each column name with the table name.
--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.
--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.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--debug-check
Print some debugging information when the program exits.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--debug-info
Print debugging information and memory and CPU usage statistics when the program exits.
This option is available only if MySQL was built using WITH_DEBUG. MySQL release binaries provided by Oracle are not built using this option.
--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.
--force, -f
Ignore all errors; 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.
If the --ignore-error option is also given to ignore specific errors, --force takes precedence.
--log-error=file_name
Log warnings and errors by appending them to the named file. The default is to do no logging.
--skip-comments
See the description for the --comments option.
--verbose, -v
Verbose mode. Print more information about what the program does.

Help Options

The following options display information about the mysqldump command itself.

--help, -?
Display a help message and exit.
--version, -V
Display version information and exit.

Internationalization Options

The following options change how the mysqldump command represents character data with national language settings.

--character-sets-dir=dir_name
The directory where character sets are installed. See Section 10.15, “Character Set Configuration”.
--default-character-set=charset_name
Use charset_name as the default character set. See Section 10.15, “Character Set Configuration”. If no character set is specified, mysqldump uses utf8.
--no-set-names, -N
Turns off the --set-charset setting, the same as specifying --skip-set-charset.
--set-charset
Write SET NAMES default_character_set to the output. This option is enabled by default. To suppress the SET NAMES statement, use --skip-set-charset.

Replication Options

The mysqldump command is frequently used to create an empty instance, or an instance including data, on a replica server in a replication configuration. The following options apply to dumping and restoring data on replication source servers and replicas.

--apply-slave-statements
For a replica dump produced with the --dump-slave option, add a STOP REPLICA | SLAVE statement before the statement with the binary log coordinates, and a START REPLICA | SLAVE statement at the end of the output.
--delete-master-logs
On a replication source server, delete the binary logs by sending a PURGE BINARY LOGS statement to the server after performing the dump operation. This option requires the RELOAD privilege as well as privileges sufficient to execute that statement. This option automatically enables --master-data.
--dump-slave[=value]
This option is similar to --master-data except that it is used to dump a replica server to produce a dump file that can be used to set up another server as a replica that has the same source as the dumped server. It causes the dump output to include a CHANGE REPLICATION SOURCE TO statement (from MySQL 8.0.23) or CHANGE MASTER TO statement (before MySQL 8.0.23) that indicates the binary log coordinates (file name and position) of the dumped replica's source. The CHANGE REPLICATION SOURCE TO statement reads the values of Relay_Master_Log_File and Exec_Master_Log_Pos from the SHOW REPLICA | SLAVE STATUS output and uses them for SOURCE_LOG_FILE and SOURCE_LOG_POS respectively. These are the replication source server coordinates from which the replica starts replicating.

Note

Inconsistencies in the sequence of transactions from the relay log which have been executed can cause the wrong position to be used. See Section 17.5.1.34, “Replication and Transaction Inconsistencies” for more information.

--dump-slave causes the coordinates from the source to be used rather than those of the dumped server, as is done by the --master-data option. In addition, specifiying this option causes the --master-data option to be overridden, if used, and effectively ignored.

Warning

This option should not be used if the server where the dump is going to be applied uses gtid_mode=ON and MASTER_AUTOPOSITION=1.

The option value is handled the same way as for --master-data. Setting no value or 1 causes a CHANGE REPLICATION SOURCE TO statement (from MySQL 8.0.23) or CHANGE MASTER TO statement (before MySQL 8.0.23) to be written to the dump. Setting 2 causes the statement to be written but encased in SQL comments. It has the same effect as --master-data in terms of enabling or disabling other options and in how locking is handled.
This option causes mysqldump to stop the replication SQL thread before the dump and restart it again after.
--dump-slave sends a SHOW REPLICA | SLAVE STATUS statement to the server to obtain information, so it requires privileges sufficient to execute that statement.
In conjunction with --dump-slave, the --apply-slave-statements and --include-master-host-port options can also be used.
--include-master-host-port
For the CHANGE REPLICATION SOURCE TO statement (from MySQL 8.0.23) or CHANGE MASTER TO statement (before MySQL 8.0.23) in a replica dump produced with the --dump-slave option, add SOURCE_HOST | MASTER_HOST and SOURCE_PORT | MASTER_PORT options for the host name and TCP/IP port number of the replica's source.
--master-data[=value]
Use this option to dump a replication source server to produce a dump file that can be used to set up another server as a replica of the source. It causes the dump output to include a CHANGE REPLICATION SOURCE TO statement (from MySQL 8.0.23) or CHANGE MASTER TO statement (before MySQL 8.0.23) that indicates the binary log coordinates (file name and position) of the dumped server. These are the replication source server coordinates from which the replica should start replicating after you load the dump file into the replica.
If the option value is 2, the CHANGE REPLICATION SOURCE TO | 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.
--master-data sends a SHOW MASTER STATUS statement to the server to obtain information, so it requires privileges sufficient to execute that statement. This option also 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 replica by dumping an existing replica of the source, using the --dump-slave option, which overrides --master-data and causes it to be ignored if both options are used.
--set-gtid-purged=value
This option is for servers that use GTID-based replication (gtid_mode=ON). It controls the inclusion of a SET @@GLOBAL.gtid_purged statement in the dump output, which updates the value of gtid_purged on a server where the dump file is reloaded, to add the GTID set from the source server's gtid_executed system variable. gtid_purged holds the GTIDs of all transactions that have been applied on the server, but do not exist on any binary log file on the server. mysqldump therefore adds the GTIDs for the transactions that were executed on the source server, so that the target server records these transactions as applied, although it does not have them in its binary logs. --set-gtid-purged also controls the inclusion of a SET @@SESSION.sql_log_bin=0 statement, which disables binary logging while the dump file is being reloaded. This statement prevents new GTIDs from being generated and assigned to the transactions in the dump file as they are executed, so that the original GTIDs for the transactions are used.
If you do not set the --set-gtid-purged option, the default is that a SET @@GLOBAL.gtid_purged statement is included in the dump output if GTIDs are enabled on the server you are backing up, and the set of GTIDs in the global value of the gtid_executed system variable is not empty. A SET @@SESSION.sql_log_bin=0 statement is also included if GTIDs are enabled on the server.
In MySQL 5.6 and 5.7, you can replace the value of gtid_purged with a specified GTID set, provided that gtid_executed and gtid_purged are empty. From MySQL 8.0, you can either replace the value of gtid_purged with a specified GTID set, or you can add a plus sign (+) to the statement to append a specified GTID set to the GTID set that is already held by gtid_purged. mysqldump's SET @@GLOBAL.gtid_purged statement includes a plus sign (+) in a version comment that takes effect when the dump file is replayed on releases from MySQL 8.0, meaning that for these releases, the GTID set from the dump file is added to the existing gtid_purged value. For MySQL 5.6 and 5.7, the value of gtid_purged is replaced with the GTID set from the dump file, which can only happen when gtid_executed is the empty set (so when replication has not been started previously, or when replication was not previously using GTIDs). For the exact details of how the SET @@GLOBAL.gtid_purged statement operates, see the gtid_purged description for the release where the dump file is to be replayed.
It is important to note that the value that is included by mysqldump for the SET @@GLOBAL.gtid_purged statement includes the GTIDs of all transactions in the gtid_executed set on the server, even those that changed suppressed parts of the database, or other databases on the server that were not included in a partial dump. This can mean that after the gtid_purged value has been updated on the server where the dump file is replayed, GTIDs are present that do not relate to any data on the target server. If you do not replay any further dump files on the target server, the extraneous GTIDs do not cause any problems with the future operation of the server, but they make it harder to compare or reconcile GTID sets on different servers in the replication topology. If you do replay a further dump file on the target server that contains the same GTIDs (for example, another partial dump from the same origin server), any SET @@GLOBAL.gtid_purged statement in the second dump file fails. In this case, either remove the statement manually before replaying the dump file, or output the dump file without the statement.

Note

For MySQL 5.6 and 5.7, it is not recommended to load a dump file when GTIDs are enabled on the server (gtid_mode=ON), if your dump file includes system tables. mysqldump issues DML instructions for the system tables which use the non-transactional MyISAM storage engine, and this combination is not permitted when GTIDs are enabled.

If the SET @@GLOBAL.gtid_purged statement would not have the desired result on your target server, you can exclude the statement from the output, or (from MySQL 8.0.17) include it but comment it out so that it is not actioned automatically. You can also include the statement but manually edit it in the dump file to achieve the desired result.
The possible values for the --set-gtid-purged option are as follows:

AUTO
The default value. If GTIDs are enabled on the server you are backing up and gtid_executed is not empty, SET @@GLOBAL.gtid_purged is added to the output, containing the GTID set from gtid_executed. If GTIDs are enabled, SET @@SESSION.sql_log_bin=0 is added to the output. If GTIDs are not enabled on the server, the statements are not added to the output.
OFF
SET @@GLOBAL.gtid_purged is not added to the output, and SET @@SESSION.sql_log_bin=0 is not added to the output. For a server where GTIDs are not in use, use this option or AUTO. Only use this option for a server where GTIDs are in use if you are sure that the required GTID set is already present in gtid_purged on the target server and should not be changed, or if you plan to identify and add any missing GTIDs manually.
ON
If GTIDs are enabled on the server you are backing up, SET @@GLOBAL.gtid_purged is added to the output (unless gtid_executed is empty), and SET @@SESSION.sql_log_bin=0 is added to the output. An error occurs if you set this option but GTIDs are not enabled on the server. For a server where GTIDs are in use, use this option or AUTO, unless you are sure that the GTIDs in gtid_executed are not needed on the target server.
COMMENTED
Available from MySQL 8.0.17. If GTIDs are enabled on the server you are backing up, SET @@GLOBAL.gtid_purged is added to the output (unless gtid_executed is empty), but it is commented out. This means that the value of gtid_executed is available in the output, but no action is taken automatically when the dump file is reloaded. SET @@SESSION.sql_log_bin=0 is added to the output, and it is not commented out. With COMMENTED, you can control the use of the gtid_executed set manually or through automation. For example, you might prefer to do this if you are migrating data to another server that already has different active databases.

Format Options

The following options specify how to represent the entire dump file or certain kinds of data in the dump file. They also control whether certain optional information is written to the dump file.

--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 only permitted value for this option is ansi, which has the same meaning as the corresponding option for setting the server SQL mode. See Section 5.1.11, “Server SQL Modes”.
--complete-insert, -c
Use complete INSERT statements that include column names.
--create-options
Include all MySQL-specific table options in the CREATE TABLE statements.
--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. See Section 13.2.7, “LOAD DATA Statement”.
--hex-blob
Dump binary columns using hexadecimal notation (for example, 'abc' becomes 0x616263). The affected data types are BINARY, VARBINARY, BLOB types, BIT, all spatial data types, and other non-binary data types when used with the binary character set.
--lines-terminated-by=...
This option is used with the --tab option and has the same meaning as the corresponding LINES clause for LOAD DATA. See Section 13.2.7, “LOAD DATA Statement”.
--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.
--result-file=file_name, -r file_name
Direct output to the named file. The result file is created and its previous contents overwritten, even if an error occurs while generating the dump.
This option should be used on Windows to prevent newline \n characters from being converted to \r\n carriage return/newline sequences.
--show-create-skip-secondary-engine=value
Excludes the SECONDARY ENGINE clause from CREATE TABLE statements. It does so by enabling the show_create_table_skip_secondary_engine system variable for the duration of the dump operation. Alternatively, you can enable the show_create_table_skip_secondary_engine system variable prior to using mysqldump.
This option was added in MySQL 8.0.18. Attempting a mysqldump operation with the --show-create-skip-secondary-engine option on a release prior to MySQL 8.0.18 that does not support the show_create_table_skip_secondary_engine variable causes an error.
--tab=dir_name, -T dir_name
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.

Note

This option should be used only when mysqldump is run on the same machine as the mysqld server. Because the server creates *.txt files in the directory that you specify, the directory must be writable by the server and the MySQL account that you use must have the FILE privilege. Because mysqldump creates *.sql in the same directory, it must be writable by your system login account.

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.
--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.

--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 Client 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>

Filtering Options

The following options control which kinds of schema objects are written to the dump file: by category, such as triggers or events; by name, for example, choosing which databases and tables to dump; or even filtering rows from the table data using a WHERE clause.

--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.

Note

See the --add-drop-database description for information about an incompatibility of that option with --all-databases.

Prior to MySQL 8.0, the --routines and --events options for mysqldump and mysqlpump were not required to include stored routines and events when using the --all-databases option: The dump included the mysql system database, and therefore also the mysql.proc and mysql.event tables containing stored routine and event definitions. As of MySQL 8.0, the mysql.event and mysql.proc tables are not used. Definitions for the corresponding objects are stored in data dictionary tables, but those tables are not dumped. To include stored routines and events in a dump made using --all-databases, use the --routines and --events options explicitly.
--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.
This option may be used to dump the performance_schema database, which normally is not dumped even with the --all-databases option. (Also use the --skip-lock-tables option.)

Note

See the --add-drop-database description for information about an incompatibility of that option with --databases.
--events, -E
Include Event Scheduler events for the dumped databases in the output. This option requires the EVENT privileges for those databases.
The output generated by using --events contains CREATE EVENT statements to create the events.
--ignore-error=error[,error]...
Ignore the specified errors. The option value is a list of comma-separated error numbers specifying the errors to ignore during mysqldump execution. If the --force option is also given to ignore all errors, --force takes precedence.
--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.
--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).
--routines, -R
Include stored routines (procedures and functions) for the dumped databases in the output. This option requires the global SELECT privilege.
The output generated by using --routines contains CREATE PROCEDURE and CREATE FUNCTION statements to create the routines.
--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.
To be able to dump a table's triggers, you must have the TRIGGER privilege for the table.
Multiple triggers are permitted. mysqldump dumps triggers in activation order so that when the dump file is reloaded, triggers are created in the same activation order. However, if a mysqldump dump file contains multiple triggers for a table that have the same trigger event and action time, an error occurs for attempts to load the dump file into an older server that does not support multiple triggers. (For a workaround, see Downgrade Notes; you can convert triggers to be compatible with older servers.)
--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"
```

Performance Options

The following options are the most relevant for the performance particularly of the restore operations. For large data sets, restore operation (processing the INSERT statements in the dump file) is the most time-consuming part. When it is urgent to restore data quickly, plan and test the performance of this stage in advance. For restore times measured in hours, you might prefer an alternative backup and restore solution, such as MySQL Enterprise Backup for InnoDB-only and mixed-use databases.

Performance is also affected by the transactional options, primarily for the dump operation.

--column-statistics
Add ANALYZE TABLE statements to the output to generate histogram statistics for dumped tables when the dump file is reloaded. This option is disabled by default because histogram generation for large tables can take a long time.
--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.
--extended-insert, -e
Write INSERT statements using multiple-row syntax that includes several VALUES lists. This results in a smaller dump file and speeds up inserts when the file is reloaded.
--insert-ignore
Write INSERT IGNORE statements rather than INSERT statements.
--max-allowed-packet=value
The maximum size of the buffer for client/server communication. The default is 24MB, the maximum is 1GB.
--net-buffer-length=value
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 bytes long. If you increase this variable, ensure that the MySQL server net_buffer_length system variable has a value at least this large.
--network-timeout, -M
Enable large tables to be dumped by setting --max-allowed-packet to its maximum value and network read and write timeouts to a large value. This option is enabled by default. To disable it, use --skip-network-timeout.
--opt
This option, enabled by default, is shorthand for the combination of --add-drop-table --add-locks --create-options --disable-keys --extended-insert --lock-tables --quick --set-charset. It gives a fast dump operation and produces a dump file that can be reloaded into a MySQL server quickly.
Because the --opt option is enabled by default, you only specify its converse, the --skip-opt to turn off several default settings. See the discussion of mysqldump option groups for information about selectively enabling or disabling a subset of the options affected by --opt.
--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.
--skip-opt