MYSQLDUMP(1) MySQL Database System MYSQLDUMP(1)
NAME
mysqldump - a database backup program
SYNOPSIS
mysqldump [options] [db_name [tbl_name ...]]
DESCRIPTION
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.
o Performance and Scalability Considerations
o Invocation Syntax
o Option Syntax - Alphabetical Summary
o Connection Options
o Option-File Options
o DDL Options
o Debug Options
o Help Options
o Internationalization Options
o Replication Options
o Format Options
o Filtering Options
o Performance Options
o Transactional Options
o Option Groups
o Examples
o Restrictions
Note
If you have tables that contain generated columns, use the mysqldump utility provided with MySQL 5.7.9 or higher to create your dump
files. The mysqldump utility provided in earlier releases uses incorrect syntax for generated column definitions (Bug #20769542). You
can use the INFORMATION_SCHEMA.COLUMNS table to identify tables with generated columns.
mysqldump requires at least the SELECT privilege for dumped tables, SHOW VIEW for dumped views, TRIGGER for dumped triggers, and LOCK
TABLES if the --single-transaction 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:
shell> mysqldump [options] > dump.sql
However, UTF-16 is not permitted as a connection character set (see Section 10.4, "Connection Character Sets and Collations"), so the
dump file will not load correctly. To work around this issue, use the --result-file option, which creates the output in ASCII format:
shell> mysqldump [options] --result-file=dump.sql
Performance and Scalability Considerations.PP 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:
o 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 29.2, "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.PP 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:
shell> mysqldump [options] db_name [tbl_name ...]
shell> mysqldump [options] --databases db_name ...
shell> 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.PP 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 4.2.6, "Using Option Files". Connection
Options.PP 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.
o --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.
o --compress, -C
Compress all information sent between the client and the server if both support compression.
o --default-auth=plugin
A hint about the client-side authentication plugin to use. See Section 6.3.9, "Pluggable Authentication".
o --enable-cleartext-plugin
Enable the mysql_clear_password cleartext authentication plugin. (See Section 6.5.1.6, "Client-Side Cleartext Pluggable
Authentication".)
This option was added in MySQL 5.7.10.
o --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 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 6.5.1.5, "Caching SHA-2 Pluggable Authentication".
The --get-server-public-key option was added in MySQL 5.7.23.
o --host=host_name, -h host_name
Dump data from the MySQL server on the given host. The default host is localhost.
o --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 mysql_config_editor(1).
o --password[=password], -p[password]
The password to use when connecting to the server. If you use the short option form (-p), you cannot have a space between the option
and the password. If you omit the password value following the --password or -p option on the command line, mysqldump prompts for one.
Specifying a password on the command line should be considered insecure. See Section 6.1.2.1, "End-User Guidelines for Password
Security". You can use an option file to avoid giving the password on the command line.
o --pipe, -W
On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections.
o --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 6.3.9, "Pluggable Authentication".
o --port=port_num, -P port_num
The TCP/IP port number to use for the connection.
o --protocol={TCP|SOCKET|PIPE|MEMORY}
The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a
protocol to be used other than the one you want. For details on the permissible values, see Section 4.2.2, "Connecting to the MySQL
Server".
o --secure-auth
Do not send passwords to the server in old (pre-4.1) format. This prevents connections except for servers that use the newer password
format.
As of MySQL 5.7.5, this option is deprecated and will be removed in a future MySQL release. It is always enabled and attempting to
disable it (--skip-secure-auth, --secure-auth=0) produces an error. Before MySQL 5.7.5, this option is enabled by default but can be
disabled.
Note
Passwords that use the pre-4.1 hashing method are less secure than passwords that use the native password hashing method and should
be avoided. Pre-4.1 passwords are deprecated and support for them was removed in MySQL 5.7.5. For account upgrade instructions, see
Section 6.5.1.3, "Migrating Away from Pre-4.1 Password Hashing and the mysql_old_password Plugin".
o --server-public-key-path=file_name
The path name to a file containing a client-side copy of the public key required by the server for RSA key pair-based password
exchange. The file must be in PEM format. 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 6.5.1.4, "SHA-256 Pluggable Authentication",
and Section 6.5.1.5, "Caching SHA-2 Pluggable Authentication".
The --server-public-key-path option was added in MySQL 5.7.23.
o --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.
o --ssl*
Options that begin with --ssl specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates.
See Section 6.4.2, "Command Options for Encrypted Connections".
o --tls-version=protocol_list
The protocols permitted by the client for encrypted connections. The value is a comma-separated list containing one or more protocol
names. The protocols that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.4.6,
"Encrypted Connection Protocols and Ciphers".
This option was added in MySQL 5.7.10.
o --user=user_name, -u user_name
The MySQL user name to use when connecting to the server.
You can also set the following variables by using --var_name=value syntax:
o max_allowed_packet
The maximum size of the buffer for client/server communication. The default is 24MB, the maximum is 1GB.
o net_buffer_length
The initial size of the buffer for client/server communication. When creating multiple-row INSERT statements (as with the
--extended-insert or --opt option), mysqldump creates rows up to net_buffer_length bytes long. If you increase this variable, ensure
that the MySQL server net_buffer_length system variable has a value at least this large.
Option-File Options.PP These options are used to control which option files to read.
o --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. file_name is interpreted relative to the current directory if given as a relative path name
rather than a full path name.
o --defaults-file=file_name
Use 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.
Exception: Even with --defaults-file, client programs read .mylogin.cnf.
o --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 the --defaults-group-suffix=_other option is given, mysqldump also reads the [client_other] and
[mysqldump_other] groups.
o --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, if it exists, is read in all cases. This permits passwords to be specified in a safer way
than on the command line even when --no-defaults is used. (.mylogin.cnf is created by the mysql_config_editor utility. See
mysql_config_editor(1).)
o --print-defaults
Print the program name and all options that it gets from option files.
DDL Options.PP 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.
o --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.
o --add-drop-table
Write a DROP TABLE statement before each CREATE TABLE statement.
o --add-drop-trigger
Write a DROP TRIGGER statement before each CREATE TRIGGER statement.
o --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, which are not supported in MySQL
5.7.
o --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.
o --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.
o --no-tablespaces, -y
This option suppresses all CREATE LOGFILE GROUP and CREATE TABLESPACE statements in the output of mysqldump.
o --replace
Write REPLACE statements rather than INSERT statements.
Debug Options.PP The following options print debugging information, encode debugging information in the dump file, or let the dump
operation proceed regardless of potential problems.
o --allow-keywords
Permit creation of column names that are keywords. This works by prefixing each column name with the table name.
o --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.
o --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.
o --debug-check
Print some debugging information when the program exits.
o --debug-info
Print debugging information and memory and CPU usage statistics when the program exits.
o --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.
o --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.
o --log-error=file_name
Log warnings and errors by appending them to the named file. The default is to do no logging.
o --skip-comments
See the description for the --comments option.
o --verbose, -v
Verbose mode. Print more information about what the program does.
Help Options.PP The following options display information about the mysqldump command itself.
o --help, -?
Display a help message and exit.
o --version, -V
Display version information and exit.
Internationalization Options.PP The following options change how the mysqldump command represents character data with national language
settings.
o --character-sets-dir=dir_name
The directory where character sets are installed. See Section 10.14, "Character Set Configuration".
o --default-character-set=charset_name
Use charset_name as the default character set. See Section 10.14, "Character Set Configuration". If no character set is specified,
mysqldump uses utf8.
o --no-set-names, -N
Turns off the --set-charset setting, the same as specifying --skip-set-charset.
o --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.PP The mysqldump command is frequently used to create an empty instance, or an instance including data, on a slave
server in a replication configuration. The following options apply to dumping and restoring data on replication master and slave servers.
o --apply-slave-statements
For a slave dump produced with the --dump-slave option, add a STOP SLAVE statement before the CHANGE MASTER TO statement and a START
SLAVE statement at the end of the output.
o --delete-master-logs
On a master replication server, delete the binary logs by sending a PURGE BINARY LOGS statement to the server after performing the dump
operation. This option automatically enables --master-data.
o --dump-slave[=value]
This option is similar to --master-data except that it is used to dump a replication slave server to produce a dump file that can be
used to set up another server as a slave that has the same master as the dumped server. It causes the dump output to include a CHANGE
MASTER TO statement that indicates the binary log coordinates (file name and position) of the dumped slave's master. The CHANGE MASTER
TO statement reads the values of Relay_Master_Log_File and Exec_Master_Log_Pos from the SHOW SLAVE STATUS output and uses them for
MASTER_LOG_FILE and MASTER_LOG_POS respectively. These are the master server coordinates from which the slave should start 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 16.4.1.33, "Replication and Transaction Inconsistencies" for more information.
--dump-slave causes the coordinates from the master to be used rather than those of the dumped server, as is done by the --master-data
option. In addition, specfiying 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 MASTER TO statement to be written
to the dump, setting 2 causes the statement to be written but encased in SQL comments) and 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 slave SQL thread before the dump and restart it again after.
In conjunction with --dump-slave, the --apply-slave-statements and --include-master-host-port options can also be used.
o --include-master-host-port
For the CHANGE MASTER TO statement in a slave dump produced with the --dump-slave option, add MASTER_HOST and MASTER_PORT options for
the host name and TCP/IP port number of the slave's master.
o --master-data[=value]
Use this option to dump a master replication server to produce a dump file that can be used to set up another server as a slave of the
master. It causes the dump output to include a CHANGE MASTER TO statement that indicates the binary log coordinates (file name and
position) of the dumped server. These are the master server coordinates from which the slave should start replicating after you load
the dump file into the slave.
If the option value is 2, the CHANGE MASTER TO statement is written as an SQL comment, and thus is informative only; it has no effect
when the dump file is reloaded. If the option value is 1, the statement is not written as a comment and takes effect when the dump file
is reloaded. If no option value is specified, the default value is 1.
This option requires the RELOAD privilege and the binary log must be enabled.
The --master-data option automatically turns off --lock-tables. It also turns on --lock-all-tables, unless --single-transaction also is
specified, in which case, a global read lock is acquired only for a short time at the beginning of the dump (see the description for
--single-transaction). In all cases, any action on logs happens at the exact moment of the dump.
It is also possible to set up a slave by dumping an existing slave of the master, using the --dump-slave option, which overrides
--master-data and causes it to be ignored if both options are used.
o --set-gtid-purged=value
This option enables control over global transaction ID (GTID) information written to the dump file, by indicating whether to add a SET
@@global.gtid_purged statement to the output. This option may also cause a statement to be written to the output that disables binary
logging while the dump file is being reloaded.
The following table shows the permitted option values. The default value is AUTO.
+------+------------------------------------------------+
|Value | Meaning |
+------+------------------------------------------------+
|OFF | Add no SET statement to the output. |
+------+------------------------------------------------+
|ON | Add a SET statement to the output. An error |
| | occurs if |
| | GTIDs are not enabled on the |
| | server. |
+------+------------------------------------------------+
|AUTO | Add a SET statement to the output if GTIDs are |
| | enabled on the server. |
+------+------------------------------------------------+
A partial dump from a server that is using GTID-based replication requires the --set-gtid-purged={ON|OFF} option to be specified. Use
ON if the intention is to deploy a new replication slave using only some of the data from the dumped server. Use OFF if the intention
is to repair a table by copying it within a topology. Use OFF if the intention is to copy a table between replication topologies that
are disjoint and will remain so.
The --set-gtid-purged option has the following effect on binary logging when the dump file is reloaded:
o --set-gtid-purged=OFF: SET @@SESSION.SQL_LOG_BIN=0; is not added to the output.
o --set-gtid-purged=ON: SET @@SESSION.SQL_LOG_BIN=0; is added to the output.
o --set-gtid-purged=AUTO: SET @@SESSION.SQL_LOG_BIN=0; is added to the output if GTIDs are enabled on the server you are backing up
(that is, if AUTO evaluates to ON).
Note
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. Also be aware that loading a dump file from a server with GTIDs enabled, into
another server with GTIDs enabled, causes different transaction identifiers to be generated.
Format Options.PP 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.
o --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.
o --compatible=name
Produce output that is more compatible with other database systems or with older MySQL servers. The value of name can be ansi,
mysql323, mysql40, postgresql, oracle, mssql, db2, maxdb, no_key_options, no_table_options, or no_field_options. To use several values,
separate them by commas. These values have the same meaning as the corresponding options for setting the server SQL mode. See
Section 5.1.10, "Server SQL Modes".
This option does not guarantee compatibility with other servers. It only enables those SQL mode values that are currently available for
making dump output more compatible. For example, --compatible=oracle does not map data types to Oracle types or use Oracle comment
syntax.
o --complete-insert, -c
Use complete INSERT statements that include column names.
o --create-options
Include all MySQL-specific table options in the CREATE TABLE statements.
o --fields-terminated-by=..., --fields-enclosed-by=..., --fields-optionally-enclosed-by=..., --fields-escaped-by=...
These options are used with the --tab option and have the same meaning as the corresponding FIELDS clauses for LOAD DATA INFILE. See
Section 13.2.6, "LOAD DATA INFILE Syntax".
o --hex-blob
Dump binary columns using hexadecimal notation (for example, 'abc' becomes 0x616263). The affected data types are BINARY, VARBINARY,
the BLOB types, and BIT.
o --lines-terminated-by=...
This option is used with the --tab option and has the same meaning as the corresponding LINES clause for LOAD DATA INFILE. See
Section 13.2.6, "LOAD DATA INFILE Syntax".
o --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.
o --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
characters from being converted to
carriage return/newline sequences.
o --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.
o --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.
o --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" /> |
+---------------------+---------------------------------------------------+
| | |
| | <field name="column_name"></field> |
+---------------------+---------------------------------------------------+
| | |
| | <field name="column_name">NULL</field> |
+---------------------+---------------------------------------------------+
The output from the mysql client when run using the --xml option also follows the preceding rules. (See the section called "MYSQL
OPTIONS".)
XML output from mysqldump includes the XML namespace, as shown here:
shell> mysqldump --xml -u root world City
<?xml version="1.0"?>
<mysqldump xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<database name="world">
<table_structure name="City">
<field Field="ID" Type="int(11)" Null="NO" Key="PRI" Extra="auto_increment" />
<field Field="Name" Type="char(35)" Null="NO" Key="" Default="" Extra="" />
<field Field="CountryCode" Type="char(3)" Null="NO" Key="" Default="" Extra="" />
<field Field="District" Type="char(20)" Null="NO" Key="" Default="" Extra="" />
<field Field="Population" Type="int(11)" Null="NO" Key="" Default="0" Extra="" />
<key Table="City" Non_unique="0" Key_name="PRIMARY" Seq_in_index="1" Column_name="ID"
Collation="A" Cardinality="4079" Null="" Index_type="BTREE" Comment="" />
<options Name="City" Engine="MyISAM" Version="10" Row_format="Fixed" Rows="4079"
Avg_row_length="67" Data_length="273293" Max_data_length="18858823439613951"
Index_length="43008" Data_free="0" Auto_increment="4080"
Create_time="2007-03-31 01:47:01" Update_time="2007-03-31 01:47:02"
Collation="latin1_swedish_ci" Create_options="" Comment="" />
</table_structure>
<table_data name="City">
<row>
<field name="ID">1</field>
<field name="Name">Kabul</field>
<field name="CountryCode">AFG</field>
<field name="District">Kabol</field>
<field name="Population">1780000</field>
</row>
...
<row>
<field name="ID">4079</field>
<field name="Name">Rafah</field>
<field name="CountryCode">PSE</field>
<field name="District">Rafah</field>
<field name="Population">92020</field>
</row>
</table_data>
</database>
</mysqldump>
Filtering Options.PP 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.
o --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.
o --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 INFORMATION_SCHEMA and performace_schema databases, which normally are not dumped even with the
--all-databases option. (Also use the --skip-lock-tables option.)
o --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. However, these statements do not include
attributes such as the event creation and modification timestamps, so when the events are reloaded, they are created with timestamps
equal to the reload time.
If you require events to be created with their original timestamp attributes, do not use --events. Instead, dump and reload the
contents of the mysql.event table directly, using a MySQL account that has appropriate privileges for the mysql database.
o --ignore-error=error[,error]...
Ignore the specified errors. The option value is a comma-separated list of error numbers specifying the errors to ignore during
mysqldump execution. If the --force option is also given to ignore all errors, --force takes precedence.
o --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.
o --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).
o --routines, -R
Include stored routines (procedures and functions) for the dumped databases in the output. This option requires the SELECT privilege
for the mysql.proc table.
The output generated by using --routines contains CREATE PROCEDURE and CREATE FUNCTION statements to create the routines. However,
these statements do not include attributes such as the routine creation and modification timestamps, so when the routines are reloaded,
they are created with timestamps equal to the reload time.
If you require routines to be created with their original timestamp attributes, do not use --routines. Instead, dump and reload the
contents of the mysql.proc table directly, using a MySQL account that has appropriate privileges for the mysql database.
o --tables
Override the --databases or -B option. mysqldump regards all name arguments following the option as table names.
o --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 Section 2.11.2.1, "Changes Affecting Downgrades from MySQL 5.7"; you can convert triggers to be
compatible with older servers.)
o --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.PP 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.
o --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.
o --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.
o --insert-ignore
Write INSERT IGNORE statements rather than INSERT statements.
o --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.
o --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.
o --skip-opt
See the description for the --opt option.
Transactional Options.PP The following options trade off the performance of the dump operation, against the reliability and consistency of
the exported data.
o --add-locks
Surround each table dump with LOCK TABLES and UNLOCK TABLES statements. This results in faster inserts when the dump file is reloaded.
See Section 8.2.4.1, "Optimizing INSERT Statements".
o --flush-logs, -F
Flush the MySQL server log files before starting the dump. This option requires the RELOAD privilege. If you use this option in
combination with the --all-databases option, the logs are flushed for each database dumped. The exception is when using
--lock-all-tables, --master-data, or --single-transaction: In this case, the logs are flushed only once, corresponding to the moment
that all tables are locked by FLUSH TABLES WITH READ LOCK. If you want your dump and the log flush to happen at exactly the same
moment, you should use --flush-logs together with --lock-all-tables, --master-data, or --single-transaction.
o --flush-privileges
Add a FLUSH PRIVILEGES statement to the dump output after dumping the mysql database. This option should be used any time the dump
contains the mysql database and any other database that depends on the data in the mysql database for proper restoration.
Note
For upgrades to MySQL 5.7 or higher from older versions, do not use --flush-privileges. For upgrade instructions in this case, see
Section 2.11.1.2, "Changes Affecting Upgrades to MySQL 5.7".
o --lock-all-tables, -x
Lock all tables across all databases. This is achieved by acquiring a global read lock for the duration of the whole dump. This option
automatically turns off --single-transaction and --lock-tables.
o --lock-tables, -l
For each dumped database, lock all tables to be dumped before dumping them. The tables are locked with READ LOCAL to permit concurrent
inserts in the case of MyISAM tables. For transactional tables such as InnoDB, --single-transaction is a much better option than
--lock-tables because it does not need to lock the tables at all.
Because --lock-tables locks tables for each database separately, this option does not guarantee that the tables in the dump file are
logically consistent between databases. Tables in different databases may be dumped in completely different states.
Some options, such as --opt, automatically enable --lock-tables. If you want to override this, use --skip-lock-tables at the end of the
option list.
o --no-autocommit
Enclose the INSERT statements for each dumped table within SET autocommit = 0 and COMMIT statements.
o --order-by-primary
Dump each table's rows sorted by its primary key, or by its first unique index, if such an index exists. This is useful when dumping a
MyISAM table to be loaded into an InnoDB table, but makes the dump operation take considerably longer.
o --shared-memory-base-name=name
On Windows, the shared-memory name to use, for connections made using shared memory to a local server. The default value is MYSQL. The
shared-memory name is case-sensitive.
The server must be started with the --shared-memory option to enable shared-memory connections.
o --single-transaction
This option sets the transaction isolation mode to REPEATABLE READ and sends a START TRANSACTION SQL statement to the server before
dumping data. It is useful only with transactional tables such as InnoDB, because then it dumps the consistent state of the database at
the time when START TRANSACTION was issued without blocking any applications.
When using this option, you should keep in mind that only InnoDB tables are dumped in a consistent state. For example, any MyISAM or
MEMORY tables dumped while using this option may still change state.
While a --single-transaction dump is in process, to ensure a valid dump file (correct table contents and binary log coordinates), no
other connection should use the following statements: ALTER TABLE, CREATE TABLE, DROP TABLE, RENAME TABLE, TRUNCATE TABLE. A consistent
read is not isolated from those statements, so use of them on a table to be dumped can cause the SELECT that is performed by mysqldump
to retrieve the table contents to obtain incorrect contents or fail.
The --single-transaction option and the --lock-tables option are mutually exclusive because LOCK TABLES causes any pending transactions
to be committed implicitly.
To dump large tables, combine the --single-transaction option with the --quick option.
Option Groups
o The --opt option turns on several settings that work together to perform a fast dump operation. All of these settings are on by
default, because --opt is on by default. Thus you rarely if ever specify --opt. Instead, you can turn these settings off as a group by
specifying --skip-opt, the optionally re-enable certain settings by specifying the associated options later on the command line.
o The --compact option turns off several settings that control whether optional statements and comments appear in the output. Again, you
can follow this option with other options that re-enable certain settings, or turn all the settings on by using the --skip-compact
form.
When you selectively enable or disable the effect of a group option, order is important because options are processed first to last. For
example, --disable-keys --lock-tables --skip-opt would not have the intended effect; it is the same as --skip-opt by itself. Examples.PP
To make a backup of an entire database:
shell> mysqldump db_name > backup-file.sql
To load the dump file back into the server:
shell> mysql db_name < backup-file.sql
Another way to reload the dump file:
shell> mysql -e "source /path-to-backup/backup-file.sql" db_name
mysqldump is also very useful for populating databases by copying data from one MySQL server to another:
shell> mysqldump --opt db_name | mysql --host=remote_host -C db_name
You can dump several databases with one command:
shell> mysqldump --databases db_name1 [db_name2 ...] > my_databases.sql
To dump all databases, use the --all-databases option:
shell> mysqldump --all-databases > all_databases.sql
For InnoDB tables, mysqldump provides a way of making an online backup:
shell> mysqldump --all-databases --master-data --single-transaction > all_databases.sql
This backup acquires a global read lock on all tables (using FLUSH TABLES WITH READ LOCK) at the beginning of the dump. As soon as this
lock has been acquired, the binary log coordinates are read and the lock is released. If long updating statements are running when the
FLUSH statement is issued, the MySQL server may get stalled until those statements finish. After that, the dump becomes lock free and does
not disturb reads and writes on the tables. If the update statements that the MySQL server receives are short (in terms of execution time),
the initial lock period should not be noticeable, even with many updates.
For point-in-time recovery (also known as "roll-forward," when you need to restore an old backup and replay the changes that happened since
that backup), it is often useful to rotate the binary log (see Section 5.4.4, "The Binary Log") or at least know the binary log coordinates
to which the dump corresponds:
shell> mysqldump --all-databases --master-data=2 > all_databases.sql
Or:
shell> mysqldump --all-databases --flush-logs --master-data=2
> all_databases.sql
The --master-data and --single-transaction options can be used simultaneously, which provides a convenient way to make an online backup
suitable for use prior to point-in-time recovery if tables are stored using the InnoDB storage engine.
For more information on making backups, see Section 7.2, "Database Backup Methods", and Section 7.3, "Example Backup and Recovery
Strategy".
o To select the effect of --opt except for some features, use the --skip option for each feature. To disable extended inserts and memory
buffering, use --opt --skip-extended-insert --skip-quick. (Actually, --skip-extended-insert --skip-quick is sufficient because --opt is
on by default.)
o To reverse --opt for all features except index disabling and table locking, use --skip-opt --disable-keys --lock-tables.
Restrictions.PP mysqldump does not dump the INFORMATION_SCHEMA, performance_schema, or sys schema by default. To dump any of these, name
them explicitly on the command line. You can also name them with the --databases option. For INFORMATION_SCHEMA and performance_schema,
also use the --skip-lock-tables option.
mysqldump does not dump the NDB Cluster ndbinfo information database.
It is not recommended to restore from a dump made using mysqldump to a MySQL 5.6.9 or earlier server that has GTIDs enabled. See
Section 16.1.3.4, "Restrictions on Replication with GTIDs".
mysqldump includes statements to recreate the general_log and slow_query_log tables for dumps of the mysql database. Log table contents are
not dumped.
If you encounter problems backing up views due to insufficient privileges, see Section C.5, "Restrictions on Views" for a workaround.
COPYRIGHT
Copyright (C) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
This documentation is free software; you can redistribute it and/or modify it only under the terms of the GNU General Public License as
published by the Free Software Foundation; version 2 of the License.
This documentation is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with the program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see http://www.gnu.org/licenses/.
SEE ALSO
For more information, please refer to the MySQL Reference Manual, which may already be installed locally and which is also available online
at http://dev.mysql.com/doc/.
AUTHOR
Oracle Corporation (http://dev.mysql.com/).
MySQL 5.7 06/07/2018 MYSQLDUMP(1)