Provided by: mysql-client-5.7_5.7.33-0ubuntu0.16.04.1_amd64 
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.
• Performance and Scalability Considerations
• Invocation Syntax
• Option Syntax - Alphabetical Summary
• Connection Options
• Option-File Options
• DDL Options
• Debug Options
• Help Options
• Internationalization Options
• Replication Options
• Format Options
• Filtering Options
• Performance Options
• Transactional Options
• Option Groups
• Examples
• Restrictions
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 5.7.31) 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:
shell> mysqldump [options] > dump.sql
However, UTF-16 is not permitted as a connection character set (see the section called
“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:
shell> 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 27.2, “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:
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
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”. 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 4.2.6, “Connection Compression Control”.
• --default-auth=plugin A hint about which client-side authentication plugin to use. See
Section 6.2.13, “Pluggable Authentication”.
• --enable-cleartext-plugin Enable the mysql_clear_password cleartext authentication
plugin. (See Section 6.4.1.6, “Client-Side Cleartext Pluggable Authentication”.)
This option was added in MySQL 5.7.10.
• --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 6.4.1.4, “Caching
SHA-2 Pluggable Authentication”.
The --get-server-public-key option was added in MySQL 5.7.23.
• --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 mysql_config_editor(1).
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 6.2.13, “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 4.2.5, “Connection Transport Protocols”.
• --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; expect it to 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 6.4.1.3, “Migrating Away from Pre-4.1 Password
Hashing and the mysql_old_password Plugin”.
• --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 6.4.1.5, “SHA-256 Pluggable Authentication”, and Section 6.4.1.4, “Caching
SHA-2 Pluggable Authentication”.
The --server-public-key-path option was added in MySQL 5.7.23.
• --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
SSL and indicate where to find SSL keys and certificates. See the section called
“Command Options for Encrypted Connections”.
• --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”.
This option was added in MySQL 5.7.10.
• --user=user_name, -u user_name The user name of the MySQL account to use for
connecting to the server.
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. file_name is interpreted relative to the current
directory if given as a relative path name rather than a full path name.
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. 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.
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 the --defaults-group-suffix=_other option is
given, 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, 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).)
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.
• --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,
which are not supported in MySQL 5.7.
• --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 and replica servers.
• --apply-slave-statements For a replica 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.
• --delete-master-logs On a source replication 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 replication 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 MASTER TO statement that indicates the binary log
coordinates (file name and position) of the dumped replica's source. 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 source server coordinates from which the replica 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 16.4.1.32,
“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 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 replica SQL thread before the dump and
restart it again after.
--dump-slave sends a SHOW 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 MASTER TO statement in a replica 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 replica's source.
• --master-data[=value] Use this option to dump a source replication 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 MASTER TO statement that indicates the
binary log coordinates (file name and position) of the dumped server. These are the
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 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 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 replica 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 for them to remain so.
The --set-gtid-purged option has the following effect on binary logging when the dump
file is reloaded:
• --set-gtid-purged=OFF: SET @@SESSION.SQL_LOG_BIN=0; is not added to the output.
• --set-gtid-purged=ON: SET @@SESSION.SQL_LOG_BIN=0; is added to the output.
• --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
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 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.
• --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 13.2.6, “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 13.2.6, “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.
• --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" /> │
├─────────────────────┼────────────────────────────────────────────┤
│ │ │
│ │ <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 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.
• --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 performance_schema
databases, which normally are not dumped even with the --all-databases option. (Also
use the --skip-lock-tables option.)
• --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.
• --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 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.
• --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
Section 2.12.3, “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.
• --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.
• --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 See the description for the --opt option.
Transactional Options
The following options trade off the performance of the dump operation, against the
reliability and consistency of the exported data.
• --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”.
• --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.
• --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.
Because the dump file contains a FLUSH PRIVILEGES statement, reloading the file
requires privileges sufficient to execute that statement.
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 2.11.3,
“Changes in MySQL 5.7”.
• --lock-all-tables, -x Lock all tables across all databases. This is achieved by
acquiring a global read lock for the duration of the whole dump. This option
automatically turns off --single-transaction and --lock-tables.
• --lock-tables, -l For each dumped database, lock all tables to be dumped before
dumping them. The tables are locked with READ LOCAL to permit concurrent inserts in
the case of MyISAM tables. For transactional tables such as InnoDB,
--single-transaction is a much better option than --lock-tables because it does not
need to lock the tables at all.
Because --lock-tables locks tables for each database separately, this option does not
guarantee that the tables in the dump file are logically consistent between databases.
Tables in different databases may be dumped in completely different states.
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.
• --no-autocommit Enclose the INSERT statements for each dumped table within SET
autocommit = 0 and COMMIT statements.
• --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.
• --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.
• --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
• 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.
• 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
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”.
• 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.)
• To reverse --opt for all features except index disabling and table locking, use
--skip-opt --disable-keys --lock-tables.
Restrictions
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.
mysqldump does not dump InnoDB CREATE TABLESPACE statements.
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 16.1.3.6, “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 22.9, “Restrictions on Views” for a workaround.
COPYRIGHT
Copyright © 1997, 2020, Oracle and/or its affiliates.
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/).