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.
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.
A dump made using PowerShell on Windows with output redirection creates a file that has UTF-16 encoding:
mysqldump [options] > dump.sql
However, UTF-16 is not permitted as a connection character set
(see
Impermissible Client Character Sets),
so the dump file cannot be loaded correctly. To work around
this issue, use the --result-file
option,
which creates the output in ASCII format:
mysqldump [options] --result-file=dump.sql
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.
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 ofInnoDB
andMyISAM
tables, consider using the mysqlbackup command of the MySQL Enterprise Backup product. (Available as part of the Enterprise subscription.) It provides the best performance forInnoDB
backups with minimal disruption; it can also back up tables fromMyISAM
and other storage engines; and it provides a number of convenient options to accommodate different backup scenarios. See Section 28.1, “MySQL Enterprise Backup Overview”.
mysqldump can retrieve and dump table
contents row by row, or it can retrieve the entire content from
a table and buffer it in memory before dumping it. Buffering in
memory can be a problem if you are dumping large tables. To dump
tables row by row, use the
--quick
option (or
--opt
, which enables
--quick
). The
--opt
option (and hence
--quick
) is enabled by
default, so to enable memory buffering, use
--skip-quick
.
If you are using a recent version of
mysqldump to generate a dump to be reloaded
into a very old MySQL server, use the
--skip-opt
option instead of
the --opt
or
--extended-insert
option.
For additional information about mysqldump, see Section 7.4, “Using mysqldump for Backups”.
Invocation Syntax
There are in general three ways to use mysqldump—in order to dump a set of one or more tables, a set of one or more complete databases, or an entire MySQL server—as shown here:
mysqldump [options] db_name [tbl_name ...]
mysqldump [options] --databases db_name ...
mysqldump [options] --all-databases
To dump entire databases, do not name any tables following
db_name
, or use the
--databases
or
--all-databases
option.
To see a list of the options your version of mysqldump supports, issue the command mysqldump --help.
Option Syntax - Alphabetical Summary
mysqldump supports the following options,
which can be specified on the command line or in the
[mysqldump]
and [client]
groups of an option file. For information about option files
used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.
Table 4.16 mysqldump Options
Option Name | Description | Introduced | Deprecated |
---|---|---|---|
--add-drop-database | Add DROP DATABASE statement before each CREATE DATABASE statement | ||
--add-drop-table | Add DROP TABLE statement before each CREATE TABLE statement | ||
--add-drop-trigger | Add DROP TRIGGER statement before each CREATE TRIGGER statement | ||
--add-locks | Surround each table dump with LOCK TABLES and UNLOCK TABLES statements | ||
--all-databases | Dump all tables in all databases | ||
--allow-keywords | Allow creation of column names that are keywords | ||
--apply-slave-statements | Include STOP SLAVE prior to CHANGE MASTER statement and START SLAVE at end of output | ||
--bind-address | Use specified network interface to connect to MySQL Server | ||
--character-sets-dir | Directory where character sets are installed | ||
--comments | Add comments to dump file | ||
--compact | Produce more compact output | ||
--compatible | Produce output that is more compatible with other database systems or with older MySQL servers | ||
--complete-insert | Use complete INSERT statements that include column names | ||
--compress | Compress all information sent between client and server | ||
--create-options | Include all MySQL-specific table options in CREATE TABLE statements | ||
--databases | Interpret all name arguments as database names | ||
--debug | Write debugging log | ||
--debug-check | Print debugging information when program exits | ||
--debug-info | Print debugging information, memory, and CPU statistics when program exits | ||
--default-auth | Authentication plugin to use | ||
--default-character-set | Specify default character set | ||
--defaults-extra-file | Read named option file in addition to usual option files | ||
--defaults-file | Read only named option file | ||
--defaults-group-suffix | Option group suffix value | ||
--delete-master-logs | On a replication source server, delete the binary logs after performing the dump operation | ||
--disable-keys | For each table, surround INSERT statements with statements to disable and enable keys | ||
--dump-date | Include dump date as "Dump completed on" comment if --comments is given | ||
--dump-slave | Include CHANGE MASTER statement that lists binary log coordinates of replica's source | ||
--enable-cleartext-plugin | Enable cleartext authentication plugin | 5.7.10 | |
--events | Dump events from dumped databases | ||
--extended-insert | Use multiple-row INSERT syntax | ||
--fields-enclosed-by | This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA | ||
--fields-escaped-by | This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA | ||
--fields-optionally-enclosed-by | This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA | ||
--fields-terminated-by | This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA | ||
--flush-logs | Flush MySQL server log files before starting dump | ||
--flush-privileges | Emit a FLUSH PRIVILEGES statement after dumping mysql database | ||
--force | Continue even if an SQL error occurs during a table dump | ||
--get-server-public-key | Request RSA public key from server | 5.7.23 | |
--help | Display help message and exit | ||
--hex-blob | Dump binary columns using hexadecimal notation | ||
--host | Host on which MySQL server is located | ||
--ignore-error | Ignore specified errors | ||
--ignore-table | Do not dump given table | ||
--include-master-host-port | Include MASTER_HOST/MASTER_PORT options in CHANGE MASTER statement produced with --dump-slave | ||
--insert-ignore | Write INSERT IGNORE rather than INSERT statements | ||
--lines-terminated-by | This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA | ||
--lock-all-tables | Lock all tables across all databases | ||
--lock-tables | Lock all tables before dumping them | ||
--log-error | Append warnings and errors to named file | ||
--login-path | Read login path options from .mylogin.cnf | ||
--master-data | Write the binary log file name and position to the output | ||
--max-allowed-packet | Maximum packet length to send to or receive from server | ||
--net-buffer-length | Buffer size for TCP/IP and socket communication | ||
--no-autocommit | Enclose the INSERT statements for each dumped table within SET autocommit = 0 and COMMIT statements | ||
--no-create-db | Do not write CREATE DATABASE statements | ||
--no-create-info | Do not write CREATE TABLE statements that re-create each dumped table | ||
--no-data | Do not dump table contents | ||
--no-defaults | Read no option files | ||
--no-set-names | Same as --skip-set-charset | ||
--no-tablespaces | Do not write any CREATE LOGFILE GROUP or CREATE TABLESPACE statements in output | ||
--opt | Shorthand for --add-drop-table --add-locks --create-options --disable-keys --extended-insert --lock-tables --quick --set-charset | ||
--order-by-primary | Dump each table's rows sorted by its primary key, or by its first unique index | ||
--password | Password to use when connecting to server | ||
--pipe | Connect to server using named pipe (Windows only) | ||
--plugin-dir | Directory where plugins are installed | ||
--port | TCP/IP port number for connection | ||
--print-defaults | Print default options | ||
--protocol | Transport protocol to use | ||
--quick | Retrieve rows for a table from the server a row at a time | ||
--quote-names | Quote identifiers within backtick characters | ||
--replace | Write REPLACE statements rather than INSERT statements | ||
--result-file | Direct output to a given file | ||
--routines | Dump stored routines (procedures and functions) from dumped databases | ||
--secure-auth | Do not send passwords to server in old (pre-4.1) format | Yes | |
--server-public-key-path | Path name to file containing RSA public key | 5.7.23 | |
--set-charset | Add SET NAMES default_character_set to output | ||
--set-gtid-purged | Whether to add SET @@GLOBAL.GTID_PURGED to output | ||
--shared-memory-base-name | Shared-memory name for shared-memory connections (Windows only) | ||
--single-transaction | Issue a BEGIN SQL statement before dumping data from server | ||
--skip-add-drop-table | Do not add a DROP TABLE statement before each CREATE TABLE statement | ||
--skip-add-locks | Do not add locks | ||
--skip-comments | Do not add comments to dump file | ||
--skip-compact | Do not produce more compact output | ||
--skip-disable-keys | Do not disable keys | ||
--skip-extended-insert | Turn off extended-insert | ||
--skip-mysql-schema | Do not drop the mysql schema | 5.7.36 | |
--skip-opt | Turn off options set by --opt | ||
--skip-quick | Do not retrieve rows for a table from the server a row at a time | ||
--skip-quote-names | Do not quote identifiers | ||
--skip-set-charset | Do not write SET NAMES statement | ||
--skip-triggers | Do not dump triggers | ||
--skip-tz-utc | Turn off tz-utc | ||
--socket | Unix socket file or Windows named pipe to use | ||
--ssl | Enable connection encryption | ||
--ssl-ca | File that contains list of trusted SSL Certificate Authorities | ||
--ssl-capath | Directory that contains trusted SSL Certificate Authority certificate files | ||
--ssl-cert | File that contains X.509 certificate | ||
--ssl-cipher | Permissible ciphers for connection encryption | ||
--ssl-crl | File that contains certificate revocation lists | ||
--ssl-crlpath | Directory that contains certificate revocation-list files | ||
--ssl-key | File that contains X.509 key | ||
--ssl-mode | Desired security state of connection to server | 5.7.11 | |
--ssl-verify-server-cert | Verify host name against server certificate Common Name identity | ||
--tab | Produce tab-separated data files | ||
--tables | Override --databases or -B option | ||
--tls-version | Permissible TLS protocols for encrypted connections | 5.7.10 | |
--triggers | Dump triggers for each dumped table | ||
--tz-utc | Add SET TIME_ZONE='+00:00' to dump file | ||
--user | MySQL user name to use when connecting to server | ||
--verbose | Verbose mode | ||
--version | Display version information and exit | ||
--where | Dump only rows selected by given WHERE condition | ||
--xml | Produce XML output |
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.
-
Command-Line Format --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.
-
Command-Line Format --compress[={OFF|ON}]
Type Boolean Default Value OFF
Compress all information sent between the client and the server if possible. See Section 4.2.6, “Connection Compression Control”.
-
Command-Line Format --default-auth=plugin
Type String A hint about which client-side authentication plugin to use. See Section 6.2.13, “Pluggable Authentication”.
-
Command-Line Format --enable-cleartext-plugin
Introduced 5.7.10 Type Boolean Default Value FALSE
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.
-
Command-Line Format --get-server-public-key
Introduced 5.7.23 Type Boolean 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=
is given and specifies a valid public key file, it takes precedence overfile_name
--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
Command-Line Format --host
Dump data from the MySQL server on the given host. The default host is
localhost
.-
Command-Line Format --login-path=name
Type String Read options from the named login path in the
.mylogin.cnf
login path file. A “login path” is an option group containing options that specify which MySQL server to connect to and which account to authenticate as. To create or modify a login path file, use the mysql_config_editor utility. See Section 4.6.6, “mysql_config_editor — MySQL Configuration Utility”.For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--password[=
,password
]-p[
password
]Command-Line Format --password[=password]
Type String 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.-
Command-Line Format --pipe
Type String 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 thenamed_pipe_full_access_group
system variable. -
Command-Line Format --plugin-dir=dir_name
Type Directory 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”. -
Command-Line Format --port=port_num
Type Numeric Default Value 3306
For TCP/IP connections, the port number to use.
--protocol={TCP|SOCKET|PIPE|MEMORY}
Command-Line Format --protocol=type
Type String Default Value [see text]
Valid Values 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”.
-
Command-Line Format --secure-auth
Deprecated Yes 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.NotePasswords 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
Command-Line Format --server-public-key-path=file_name
Introduced 5.7.23 Type 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
orcaching_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=
is given and specifies a valid public key file, it takes precedence overfile_name
--get-server-public-key
.For
sha256_password
, this option applies only if MySQL was built using OpenSSL.For information about the
sha256_password
andcaching_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.-
Command-Line Format --skip-mysql-schema
Introduced 5.7.36 Type Boolean Do not drop the
mysql
schema when the dump file is restored. By default, the schema is dropped.This option was added in MySQL 5.7.36.
-
Command-Line Format --socket={file_name|pipe_name}
Type String 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 thenamed_pipe_full_access_group
system variable. Options that begin with
--ssl
specify whether to connect to the server using encryption and indicate where to find SSL keys and certificates. See Command Options for Encrypted Connections.-
Command-Line Format --tls-version=protocol_list
Introduced 5.7.10 Type String Default Value (≥ 5.7.28) TLSv1,TLSv1.1,TLSv1.2
Default Value (≤ 5.7.27) TLSv1,TLSv1.1,TLSv1.2
(OpenSSL)TLSv1,TLSv1.1
(yaSSL)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
Command-Line Format --user=user_name
Type String 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
Command-Line Format --defaults-extra-file=file_name
Type File name Read this option file after the global option file but (on Unix) before the user option file. If the file does not exist or is otherwise inaccessible, an error occurs. If
file_name
is not an absolute path name, it is interpreted relative to the current directory.For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
-
Command-Line Format --defaults-file=file_name
Type File name Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. If
file_name
is not an absolute path name, it is interpreted relative to the current directory.Exception: Even with
--defaults-file
, client programs read.mylogin.cnf
.For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
-
Command-Line Format --defaults-group-suffix=str
Type String Read not only the usual option groups, but also groups with the usual names and a suffix of
str
. For example, mysqldump normally reads the[client]
and[mysqldump]
groups. If this option is given as--defaults-group-suffix=_other
, mysqldump also reads the[client_other]
and[mysqldump_other]
groups.For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
-
Command-Line Format --no-defaults
Do not read any option files. If program startup fails due to reading unknown options from an option file,
--no-defaults
can be used to prevent them from being read.The exception is that the
.mylogin.cnf
file is read in all cases, if it exists. This permits passwords to be specified in a safer way than on the command line even when--no-defaults
is used. To create.mylogin.cnf
, use the mysql_config_editor utility. See Section 4.6.6, “mysql_config_editor — MySQL Configuration Utility”.For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
-
Command-Line Format --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.
-
Command-Line Format --add-drop-database
Write a
DROP DATABASE
statement before eachCREATE DATABASE
statement. This option is typically used in conjunction with the--all-databases
or--databases
option because noCREATE DATABASE
statements are written unless one of those options is specified. -
Command-Line Format --add-drop-table
Write a
DROP TABLE
statement before eachCREATE TABLE
statement. -
Command-Line Format --add-drop-trigger
Write a
DROP TRIGGER
statement before eachCREATE TRIGGER
statement. -
Command-Line Format --all-tablespaces
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. -
Command-Line Format --no-create-db
Suppress the
CREATE DATABASE
statements that are otherwise included in the output if the--databases
or--all-databases
option is given. -
Command-Line Format --no-create-info
Do not write
CREATE TABLE
statements that create each dumped table.NoteThis 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. -
Command-Line Format --no-tablespaces
This option suppresses all
CREATE LOGFILE GROUP
andCREATE TABLESPACE
statements in the output of mysqldump. -
Command-Line Format --replace
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.
-
Command-Line Format --allow-keywords
Permit creation of column names that are keywords. This works by prefixing each column name with the table name.
-
Command-Line Format --comments
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
]Command-Line Format --debug[=debug_options]
Type String Default Value d:t:o,/tmp/mysqldump.trace
Write a debugging log. A typical
debug_options
string isd:t:o,
. The default value isfile_name
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.-
Command-Line Format --debug-check
Type Boolean Default Value FALSE
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. -
Command-Line Format --debug-info
Type Boolean Default Value FALSE
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. -
Command-Line Format --dump-date
Type Boolean Default Value TRUE
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. -
Command-Line Format --force
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. -
Command-Line Format --log-error=file_name
Type File name Log warnings and errors by appending them to the named file. The default is to do no logging.
-
Command-Line Format --skip-comments
See the description for the
--comments
option. -
Command-Line Format --verbose
Verbose mode. Print more information about what the program does.
Help Options
The following options display information about the mysqldump command itself.
Internationalization Options
The following options change how the mysqldump command represents character data with national language settings.
-
Command-Line Format --character-sets-dir=dir_name
Type Directory name The directory where character sets are installed. See Section 10.15, “Character Set Configuration”.
--default-character-set=
charset_name
Command-Line Format --default-character-set=charset_name
Type String Default Value utf8
Use
charset_name
as the default character set. See Section 10.15, “Character Set Configuration”. If no character set is specified, mysqldump usesutf8
.-
Command-Line Format --no-set-names
Deprecated Yes Turns off the
--set-charset
setting, the same as specifying--skip-set-charset
. -
Command-Line Format --set-charset
Disabled by skip-set-charset
Write
SET NAMES
to the output. This option is enabled by default. To suppress thedefault_character_set
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.
-
Command-Line Format --apply-slave-statements
Type Boolean Default Value FALSE
For a replica dump produced with the
--dump-slave
option, add aSTOP SLAVE
statement before theCHANGE MASTER TO
statement and aSTART SLAVE
statement at the end of the output. -
Command-Line Format --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 theRELOAD
privilege as well as privileges sufficient to execute that statement. This option automatically enables--master-data
. -
Command-Line Format --dump-slave[=value]
Type Numeric Default Value 1
Valid Values 1
2
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 aCHANGE MASTER TO
statement that indicates the binary log coordinates (file name and position) of the dumped replica's source. TheCHANGE MASTER TO
statement reads the values ofRelay_Master_Log_File
andExec_Master_Log_Pos
from theSHOW SLAVE STATUS
output and uses them forMASTER_LOG_FILE
andMASTER_LOG_POS
respectively. These are the source server coordinates from which the replica should start replicating.NoteInconsistencies 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.WarningThis option should not be used if the server where the dump is going to be applied uses
gtid_mode=ON
andMASTER_AUTOPOSITION=1
.The option value is handled the same way as for
--master-data
(setting no value or 1 causes aCHANGE 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 aSHOW 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. -
Command-Line Format --include-master-host-port
Type Boolean Default Value FALSE
For the
CHANGE MASTER TO
statement in a replica dump produced with the--dump-slave
option, addMASTER_HOST
andMASTER_PORT
options for the host name and TCP/IP port number of the replica's source. -
Command-Line Format --master-data[=value]
Type Numeric Default Value 1
Valid Values 1
2
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 aSHOW MASTER STATUS
statement to the server to obtain information, so it requires privileges sufficient to execute that statement. This option also requires theRELOAD
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. -
Command-Line Format --set-gtid-purged=value
Type Enumeration Default Value AUTO
Valid Values OFF
ON
AUTO
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. UseON
if the intention is to deploy a new replication replica using only some of the data from the dumped server. UseOFF
if the intention is to repair a table by copying it within a topology. UseOFF
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, ifAUTO
evaluates toON
).
Using this option with the
--single-transaction
option can lead to inconsistencies in the output. If--set-gtid-purged=ON
is required, it can be used with--lock-all-tables
, but this can prevent parallel queries while mysqldump is being run.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.
-
Command-Line Format --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. -
Command-Line Format --compatible=name[,name,...]
Type String Default Value ''
Valid Values ansi
mysql323
mysql40
postgresql
oracle
mssql
db2
maxdb
no_key_options
no_table_options
no_key_options
Produce output that is more compatible with other database systems or with older MySQL servers. The value of
name
can beansi
,mysql323
,mysql40
,postgresql
,oracle
,mssql
,db2
,maxdb
,no_key_options
,no_table_options
, orno_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. -
Command-Line Format --complete-insert
Use complete
INSERT
statements that include column names. -
Command-Line Format --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=...
Command-Line Format --fields-terminated-by=string
Type String Command-Line Format --fields-enclosed-by=string
Type String Command-Line Format --fields-optionally-enclosed-by=string
Type String Command-Line Format --fields-escaped-by
Type String These options are used with the
--tab
option and have the same meaning as the correspondingFIELDS
clauses forLOAD DATA
. See Section 13.2.6, “LOAD DATA Statement”.-
Command-Line Format --hex-blob
Dump binary columns using hexadecimal notation (for example,
'abc'
becomes0x616263
). The affected data types areBINARY
,VARBINARY
,BLOB
types,BIT
, all spatial data types, and other non-binary data types when used with thebinary
character set.The
--hex-blob
option is ignored when the--tab
is used. -
Command-Line Format --lines-terminated-by=string
Type String This option is used with the
--tab
option and has the same meaning as the correspondingLINES
clause forLOAD DATA
. See Section 13.2.6, “LOAD DATA Statement”. -
Command-Line Format --quote-names
Disabled by skip-quote-names
Quote identifiers (such as database, table, and column names) within
`
characters. If theANSI_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
Command-Line Format --result-file=file_name
Type 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.-
Command-Line Format --tab=dir_name
Type Directory name Produce tab-separated text-format data files. For each dumped table, mysqldump creates a
file that contains thetbl_name
.sqlCREATE TABLE
statement that creates the table, and the server writes a
file that contains its data. The option value is the directory in which to write the files.tbl_name
.txtNoteThis 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 theFILE
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-
andxxx
--lines-terminated-by
options.Column values are converted to the character set specified by the
--default-character-set
option. -
Command-Line Format --tz-utc
Disabled by skip-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 addsSET 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
. -
Command-Line Format --xml
Write dump output as well-formed XML.
NULL
,'NULL'
, and Empty Values: For a column namedcolumn_name
, theNULL
value, an empty string, and the string value'NULL'
are distinguished from one another in the output generated by this option as follows.Value: XML Representation: NULL
(unknown value)<field name="
column_name
" xsi:nil="true" />''
(empty string)<field name="
column_name
"></field>'NULL'
(string value)<field name="
column_name
">NULL</field>The output from the mysql client when run using the
--xml
option also follows the preceding rules. (See Section 4.5.1.1, “mysql Client Options”.)XML output from mysqldump includes the XML namespace, as shown here:
$> 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.
-
Command-Line Format --all-databases
Dump all tables in all databases. This is the same as using the
--databases
option and naming all the databases on the command line. -
Command-Line Format --databases
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
andUSE
statements are included in the output before each new database.This option may be used to dump the
INFORMATION_SCHEMA
andperformance_schema
databases, which normally are not dumped even with the--all-databases
option. (Also use the--skip-lock-tables
option.) -
Command-Line Format --events
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
containsCREATE 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 themysql.event
table directly, using a MySQL account that has appropriate privileges for themysql
database. --ignore-error=
error[,error]...
Command-Line Format --ignore-error=error[,error]...
Type String 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
Command-Line Format --ignore-table=db_name.tbl_name
Type String 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.
-
Command-Line Format --no-data
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). -
Command-Line Format --routines
Include stored routines (procedures and functions) for the dumped databases in the output. This option requires the
SELECT
privilege for themysql.proc
table.The output generated by using
--routines
containsCREATE PROCEDURE
andCREATE 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 themysql.proc
table directly, using a MySQL account that has appropriate privileges for themysql
database. -
Command-Line Format --tables
Override the
--databases
or-B
option. mysqldump regards all name arguments following the option as table names. -
Command-Line Format --triggers
Disabled by skip-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 2.11.3, “Downgrade Notes”; you can convert triggers to be compatible with older servers.)
--where='
,where_condition
'-w '
where_condition
'Command-Line Format --where='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.
-
Command-Line Format --disable-keys
For each table, surround the
INSERT
statements with/*!40000 ALTER TABLE
andtbl_name
DISABLE KEYS */;/*!40000 ALTER TABLE
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 oftbl_name
ENABLE KEYS */;MyISAM
tables. -
Command-Line Format --extended-insert
Disabled by skip-extended-insert
Write
INSERT
statements using multiple-row syntax that includes severalVALUES
lists. This results in a smaller dump file and speeds up inserts when the file is reloaded. -
Command-Line Format --insert-ignore
Write
INSERT IGNORE
statements rather thanINSERT
statements. -
Command-Line Format --max-allowed-packet=value
Type Numeric Default Value 25165824
The maximum size of the buffer for client/server communication. The default is 24MB, the maximum is 1GB.
NoteThe value of this option is specific to mysqldump and should not be confused with the MySQL server's
max_allowed_packet
system variable; the server value cannot be exceeded by a single packet from mysqldump, regardless of any setting for the mysqldump option, even if the latter is larger. -
Command-Line Format --net-buffer-length=value
Type Numeric Default Value 16384
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 servernet_buffer_length
system variable has a value at least this large. -
Command-Line Format --opt
Disabled by skip-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 ofmysqldump
option groups for information about selectively enabling or disabling a subset of the options affected by--opt
. -
Command-Line Format --quick
Disabled by skip-quick
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.
-
Command-Line Format --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.
-
Command-Line Format --add-locks
Surround each table dump with
LOCK TABLES
andUNLOCK TABLES
statements. This results in faster inserts when the dump file is reloaded. See Section 8.2.4.1, “Optimizing INSERT Statements”. -
Command-Line Format --flush-logs
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 byFLUSH 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
. -
Command-Line Format --flush-privileges
Add a
FLUSH PRIVILEGES
statement to the dump output after dumping themysql
database. This option should be used any time the dump contains themysql
database and any other database that depends on the data in themysql
database for proper restoration.Because the dump file contains a
FLUSH PRIVILEGES
statement, reloading the file requires privileges sufficient to execute that statement.NoteFor upgrades to MySQL 5.7 or higher from older versions, do not use
--flush-privileges
. For upgrade instructions in this case, see Section 2.10.3, “Changes in MySQL 5.7”. -
Command-Line Format --lock-all-tables
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
. -
Command-Line Format --lock-tables
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 ofMyISAM
tables. For transactional tables such asInnoDB
,--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. -
Command-Line Format --no-autocommit
Enclose the
INSERT
statements for each dumped table withinSET autocommit = 0
andCOMMIT
statements. -
Command-Line Format --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 anInnoDB
table, but makes the dump operation take considerably longer. --shared-memory-base-name=
name
Command-Line Format --shared-memory-base-name=name
Platform Specific Windows 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.-
Command-Line Format --single-transaction
This option sets the transaction isolation mode to
REPEATABLE READ
and sends aSTART TRANSACTION
SQL statement to the server before dumping data. It is useful only with transactional tables such asInnoDB
, because then it dumps the consistent state of the database at the time whenSTART TRANSACTION
was issued without blocking any applications.The RELOAD or FLUSH_TABLES privilege is required with
--single-transaction
if both gtid_mode=ON and --set-gtid=purged=ON|AUTO. This requirement was added in MySQL 8.0.32.When using this option, you should keep in mind that only
InnoDB
tables are dumped in a consistent state. For example, anyMyISAM
orMEMORY
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 theSELECT
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 becauseLOCK TABLES
causes any pending transactions to be committed implicitly.Using
--single-transaction
together with the--set-gtid-purged
option is not recommended; doing so can lead to inconsistencies in the output of mysqldump.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
, then 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:
mysqldump db_name > backup-file.sql
To load the dump file back into the server:
mysql db_name < backup-file.sql
Another way to reload the dump file:
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:
mysqldump --opt db_name | mysql --host=remote_host -C db_name
You can dump several databases with one command:
mysqldump --databases db_name1 [db_name2 ...] > my_databases.sql
To dump all databases, use the
--all-databases
option:
mysqldump --all-databases > all_databases.sql
For InnoDB
tables,
mysqldump provides a way of making an online
backup:
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:
mysqldump --all-databases --master-data=2 > all_databases.sql
Or:
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.
mysqldump always strips the
NO_AUTO_CREATE_USER
SQL mode as
NO_AUTO_CREATE_USER
is not compatible with
MySQL 8.0. It remains stripped even when importing back into
MySQL 5.7, which means that stored routines could behave
differently after restoring a dump if they rely upon this
particular sql_mode. It is stripped as of
mysqldump 5.7.24.
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 23.9, “Restrictions on Views” for a workaround.