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4.5.4 mysqldump — A Database Backup Program
The mysqldump client utility performs logical backups, producing a set of SQL statements that can be executed to reproduce the original database object definitions and table data. It dumps one or more MySQL databases for backup or transfer to another SQL server. The mysqldump command can also generate output in CSV, other delimited text, or XML format.
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:
shell> mysqldump [options] > dump.sql
However, UTF-16 is not permitted as a connection character set (see Impermissible Client Character Sets), so the dump file will not load correctly. To work around this issue, use the --result-file
option, which creates the output in ASCII format:
shell> mysqldump [options] --result-file=dump.sql
Performance and Scalability Considerations
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 29.2, “MySQL Enterprise Backup Overview”.
mysqldump can retrieve and dump table contents row by row, or it can retrieve the entire content from a table and buffer it in memory before dumping it. Buffering in memory can be a problem if you are dumping large tables. To dump tables row by row, use the --quick
option (or --opt
, which enables --quick
). The --opt
option (and hence --quick
) is enabled by default, so to enable memory buffering, use --skip-quick
.
If you are using a recent version of mysqldump to generate a dump to be reloaded into a very old MySQL server, use the --skip-opt
option instead of the --opt
or --extended-insert
option.
For additional information about mysqldump, see Section 7.4, “Using mysqldump for Backups”.
Invocation Syntax
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”.
Table 4.15 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 master replication server, delete the binary logs after performing the dump operation | ||
--disable-keys | For each table, surround INSERT statements with statements to disable and enable keys | ||
--dump-date | Include dump date as "Dump completed on" comment if --comments is given | ||
--dump-slave | Include CHANGE MASTER statement that lists binary log coordinates of slave's master | ||
--enable-cleartext-plugin | Enable cleartext authentication plugin | 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-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.
On a computer having multiple network interfaces, use this option to select which interface to use for connecting to the MySQL server.
Compress all information sent between the client and the server if possible. See Section 4.2.6, “Connection Compression Control”.
A hint about which client-side authentication plugin to use. See Section 6.2.13, “Pluggable Authentication”.
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.
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
Dump data from the MySQL server on the given host. The default host is
localhost
.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
]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.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.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”.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”.
Do not send passwords to the server in old (pre-4.1) format. This prevents connections except for servers that use the newer password format.
As of MySQL 5.7.5, this option is deprecated and will be removed in a future MySQL release. It is always enabled and attempting to disable it (
--skip-secure-auth
,--secure-auth=0
) produces an error. Before MySQL 5.7.5, this option is enabled by default but can be disabled.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
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.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 SSL and indicate where to find SSL keys and certificates. See Command Options for Encrypted Connections.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”.
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”.
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”.
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 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”.
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.
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.Write a
DROP TABLE
statement before eachCREATE TABLE
statement.Write a
DROP TRIGGER
statement before eachCREATE TRIGGER
statement.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.Suppress the
CREATE DATABASE
statements that are otherwise included in the output if the--databases
or--all-databases
option is given.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.This option suppresses all
CREATE LOGFILE GROUP
andCREATE TABLESPACE
statements in the output of mysqldump.
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.
Permit creation of column names that are keywords. This works by prefixing each column name with the table name.
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 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.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.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.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.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 warnings and errors by appending them to the named file. The default is to do no logging.
See the description for the
--comments
option.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.
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 usesutf8
.Turns off the
--set-charset
setting, the same as specifying--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 slave server in a replication configuration. The following options apply to dumping and restoring data on replication master and slave servers.
For a slave 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.On a master replication server, delete the binary logs by sending a
PURGE BINARY LOGS
statement to the server after performing the dump operation. This option automatically enables--master-data
.This option is similar to
--master-data
except that it is used to dump a replication slave server to produce a dump file that can be used to set up another server as a slave that has the same master as the dumped server. It causes the dump output to include aCHANGE MASTER TO
statement that indicates the binary log coordinates (file name and position) of the dumped slave's master. 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 master server coordinates from which the slave 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 master to be used rather than those of the dumped server, as is done by the--master-data
option. In addition, specfiying this option causes the--master-data
option to be overridden, if used, and effectively ignored.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 slave SQL thread before the dump and restart it again after.
In conjunction with
--dump-slave
, the--apply-slave-statements
and--include-master-host-port
options can also be used.For the
CHANGE MASTER TO
statement in a slave dump produced with the--dump-slave
option, addMASTER_HOST
andMASTER_PORT
options for the host name and TCP/IP port number of the slave's master.Use this option to dump a master replication server to produce a dump file that can be used to set up another server as a slave of the master. It causes the dump output to include a
CHANGE MASTER TO
statement that indicates the binary log coordinates (file name and position) of the dumped server. These are the master server coordinates from which the slave should start replicating after you load the dump file into the slave.If the option value is 2, the
CHANGE MASTER TO
statement is written as an SQL comment, and thus is informative only; it has no effect when the dump file is reloaded. If the option value is 1, the statement is not written as a comment and takes effect when the dump file is reloaded. If no option value is specified, the default value is 1.This option requires the
RELOAD
privilege and the binary log must be enabled.The
--master-data
option automatically turns off--lock-tables
. It also turns on--lock-all-tables
, unless--single-transaction
also is specified, in which case, a global read lock is acquired only for a short time at the beginning of the dump (see the description for--single-transaction
). In all cases, any action on logs happens at the exact moment of the dump.It is also possible to set up a slave by dumping an existing slave of the master, using the
--dump-slave
option, which overrides--master-data
and causes it to be ignored if both options are used.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 slave 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 will 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
).
NoteIt 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.
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.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.Use complete
INSERT
statements that include column names.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 correspondingFIELDS
clauses forLOAD DATA
. See Section 13.2.6, “LOAD DATA Statement”.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.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”.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
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.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.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
.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:
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.
Dump all tables in all databases. This is the same as using the
--databases
option and naming all the databases on the command line.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.)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]...
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.
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).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.Override the
--databases
or-B
option. mysqldump regards all name arguments following the option as table names.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.
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.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.Write
INSERT IGNORE
statements rather thanINSERT
statements.The maximum size of the buffer for client/server communication. The default is 24MB, the maximum is 1GB.
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.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
.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.
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.
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”.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
.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.NoteFor upgrades to MySQL 5.7 or higher from older versions, do not use
--flush-privileges
. For upgrade instructions in this case, see Section 2.11.3, “Changes in MySQL 5.7”.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-transa