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, and LOCK TABLES if the
--single-transaction option is
not used. Certain options might require other privileges as
noted in the option descriptions.
To reload a dump file, you must have the privileges required to
execute the statements that it contains, such as the appropriate
CREATE privileges for objects created by
those statements.
mysqldump output can include
ALTER DATABASE statements that
change the database collation. These may be used when dumping
stored programs to preserve their character encodings. To reload
a dump file containing such statements, the
ALTER privilege for the affected database is
required.
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
InnoDBtables, or if you have a mix ofInnoDBandMyISAMtables, consider using the mysqlbackup command of the MySQL Enterprise Backup product. (Available as part of the Enterprise subscription.) It provides the best performance forInnoDBbackups with minimal disruption; it can also back up tables fromMyISAMand 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 | 5.7.1 | |
| --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 | Connection 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 | 5.7.4 | 5.7.5 |
| --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 | Name of shared memory to use for shared-memory connections | ||
| --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 4.2.5, “Connection Compression Control”.
A hint about which client-side authentication plugin to use. See Section 6.2.13, “Pluggable Authentication”.
Enable the
mysql_clear_passwordcleartext 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_passwordauthentication 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_passwordplugin, see Section 6.4.1.5, “Caching SHA-2 Pluggable Authentication”.The
--get-server-public-keyoption was added in MySQL 5.7.23.--host=,host_name-hhost_nameDump data from the MySQL server on the given host. The default host is
localhost.Read options from the named login path in the
.mylogin.cnflogin 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-pand 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-passwordoption.On Windows, connect to the server using a named pipe. This option applies only if the server was started with the
named_pipesystem 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_groupsystem variable.The directory in which to look for plugins. Specify this option if the
--default-authoption 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 connection 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 4.2.4, “Connecting to the MySQL Server Using Command Options”.
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_nameThe path name to a file containing a client-side copy of the public key required by the server for RSA key pair-based password exchange. The file must be in PEM format. This option applies to clients that authenticate with the
sha256_passwordorcaching_sha2_passwordauthentication 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_passwordandcaching_sha2_passwordplugins, see Section 6.4.1.4, “SHA-256 Pluggable Authentication”, and Section 6.4.1.5, “Caching SHA-2 Pluggable Authentication”.The
--server-public-key-pathoption 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_pipesystem 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_groupsystem variable.Options that begin with
--sslspecify 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-uuser_nameThe 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_nameRead 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_nameis 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_nameis 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=_otheroption 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-defaultscan be used to prevent them from being read.The exception is that the
.mylogin.cnffile, 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-defaultsis used. (.mylogin.cnfis 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 DATABASEstatement before eachCREATE DATABASEstatement. This option is typically used in conjunction with the--all-databasesor--databasesoption because noCREATE DATABASEstatements are written unless one of those options is specified.Write a
DROP TABLEstatement before eachCREATE TABLEstatement.Write a
DROP TRIGGERstatement before eachCREATE TRIGGERstatement.Adds to a table dump all SQL statements needed to create any tablespaces used by an
NDBtable. 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 DATABASEstatements that are otherwise included in the output if the--databasesor--all-databasesoption is given.Do not write
CREATE TABLEstatements 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-tablespacesoption for this purpose.This option suppresses all
CREATE LOGFILE GROUPandCREATE TABLESPACEstatements 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_optionsstring isd:t:o,. The default value isfile_named:t:o,/tmp/mysqldump.trace.Print some debugging information when the program exits.
Print debugging information and memory and CPU usage statistics when the program exits.
If the
--commentsoption is given, mysqldump produces a comment at the end of the dump of the following form:-- Dump completed on DATEHowever, the date causes dump files taken at different times to appear to be different, even if the data are otherwise identical.
--dump-dateand--skip-dump-datecontrol whether the date is added to the comment. The default is--dump-date(include the date in the comment).--skip-dump-datesuppresses 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-erroroption is also given to ignore specific errors,--forcetakes precedence.Log warnings and errors by appending them to the named file. The default is to do no logging.
See the description for the
--commentsoption.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_nameUse
charset_nameas the default character set. See Section 10.15, “Character Set Configuration”. If no character set is specified, mysqldump usesutf8.Turns off the
--set-charsetsetting, the same as specifying--skip-set-charset.Write
SET NAMESto the output. This option is enabled by default. To suppress thedefault_character_setSET NAMESstatement, 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-slaveoption, add aSTOP SLAVEstatement before theCHANGE MASTER TOstatement and aSTART SLAVEstatement at the end of the output.On a master replication server, delete the binary logs by sending a
PURGE BINARY LOGSstatement to the server after performing the dump operation. This option automatically enables--master-data.This option is similar to
--master-dataexcept 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 TOstatement that indicates the binary log coordinates (file name and position) of the dumped slave's master. TheCHANGE MASTER TOstatement reads the values ofRelay_Master_Log_FileandExec_Master_Log_Posfrom theSHOW SLAVE STATUSoutput and uses them forMASTER_LOG_FILEandMASTER_LOG_POSrespectively. 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-slavecauses the coordinates from the master to be used rather than those of the dumped server, as is done by the--master-dataoption. In addition, specfiying this option causes the--master-dataoption 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=ONandMASTER_AUTOPOSITION=1.The option value is handled the same way as for
--master-data(setting no value or 1 causes aCHANGE MASTER TOstatement 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-datain 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-statementsand--include-master-host-portoptions can also be used.For the
CHANGE MASTER TOstatement in a slave dump produced with the--dump-slaveoption, addMASTER_HOSTandMASTER_PORToptions 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 TOstatement 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 TOstatement 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
RELOADprivilege and the binary log must be enabled.The
--master-dataoption automatically turns off--lock-tables. It also turns on--lock-all-tables, unless--single-transactionalso 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-slaveoption, which overrides--master-dataand 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_purgedstatement 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 OFFAdd no SETstatement to the output.ONAdd a SETstatement to the output. An error occurs if GTIDs are not enabled on the server.AUTOAdd a SETstatement 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. UseONif the intention is to deploy a new replication slave using only some of the data from the dumped server. UseOFFif the intention is to repair a table by copying it within a topology. UseOFFif the intention is to copy a table between replication topologies that are disjoint and will remain so.The
--set-gtid-purgedoption 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, ifAUTOevaluates 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-charsetoptions.Produce output that is more compatible with other database systems or with older MySQL servers. The value of
namecan 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=oracledoes not map data types to Oracle types or use Oracle comment syntax.Use complete
INSERTstatements that include column names.Include all MySQL-specific table options in the
CREATE TABLEstatements.--fields-terminated-by=...,--fields-enclosed-by=...,--fields-optionally-enclosed-by=...,--fields-escaped-by=...These options are used with the
--taboption and have the same meaning as the correspondingFIELDSclauses forLOAD DATA. See Section 13.2.6, “LOAD DATA Syntax”.Dump binary columns using hexadecimal notation (for example,
'abc'becomes0x616263). The affected data types areBINARY,VARBINARY,BLOBtypes,BIT, all spatial data types, and other non-binary data types when used with thebinarycharacter set.This option is used with the
--taboption and has the same meaning as the correspondingLINESclause forLOAD DATA. See Section 13.2.6, “LOAD DATA Syntax”.Quote identifiers (such as database, table, and column names) within
`characters. If theANSI_QUOTESSQL 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--compatiblethat may enable--quote-names.--result-file=,file_name-rfile_nameDirect 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
\ncharacters from being converted to\r\ncarriage return/newline sequences.Produce tab-separated text-format data files. For each dumped table, mysqldump creates a
file that contains thetbl_name.sqlCREATE TABLEstatement that creates the table, and the server writes afile 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
*.txtfiles in the directory that you specify, the directory must be writable by the server and the MySQL account that you use must have theFILEprivilege. Because mysqldump creates*.sqlin the same directory, it must be writable by your system login account.By default, the
.txtdata 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-byoptions.Column values are converted to the character set specified by the
--default-character-setoption.This option enables
TIMESTAMPcolumns 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,TIMESTAMPcolumns 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-utcalso protects against changes due to daylight saving time.--tz-utcis 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, theNULLvalue, 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
--xmloption 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
--databasesoption 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 DATABASEandUSEstatements are included in the output before each new database.This option may be used to dump the
INFORMATION_SCHEMAandperformance_schemadatabases, which normally are not dumped even with the--all-databasesoption. (Also use the--skip-lock-tablesoption.)Include Event Scheduler events for the dumped databases in the output. This option requires the
EVENTprivileges for those databases.The output generated by using
--eventscontainsCREATE EVENTstatements 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.eventtable directly, using a MySQL account that has appropriate privileges for themysqldatabase.--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
--forceoption is also given to ignore all errors,--forcetakes precedence.--ignore-table=db_name.tbl_nameDo 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 TABLEstatement 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
SELECTprivilege for themysql.proctable.The output generated by using
--routinescontainsCREATE PROCEDUREandCREATE FUNCTIONstatements 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.proctable directly, using a MySQL account that has appropriate privileges for themysqldatabase.Override the
--databasesor-Boption. 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
TRIGGERprivilege 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
WHEREcondition. 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
INSERTstatements with/*!40000 ALTER TABLEandtbl_nameDISABLE KEYS */;/*!40000 ALTER TABLEstatements. 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_nameENABLE KEYS */;MyISAMtables.Write
INSERTstatements using multiple-row syntax that includes severalVALUESlists. This results in a smaller dump file and speeds up inserts when the file is reloaded.Write
INSERT IGNOREstatements rather thanINSERTstatements.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
INSERTstatements (as with the--extended-insertor--optoption), mysqldump creates rows up to--net-buffer-lengthbytes long. If you increase this variable, ensure that the MySQL servernet_buffer_lengthsystem 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
--optoption is enabled by default, you only specify its converse, the--skip-optto turn off several default settings. See the discussion ofmysqldumpoption 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
--optoption.
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 TABLESandUNLOCK TABLESstatements. 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
RELOADprivilege. If you use this option in combination with the--all-databasesoption, 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-logstogether with--lock-all-tables,--master-data, or--single-transaction.Add a
FLUSH PRIVILEGESstatement to the dump output after dumping themysqldatabase. This option should be used any time the dump contains themysqldatabase and any other database that depends on the data in themysqldatabase 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-transactionand--lock-tables.For each dumped database, lock all tables to be dumped before dumping them. The tables are locked with
READ LOCALto permit concurrent inserts in the case ofMyISAMtables. For transactional tables such asInnoDB,--single-transactionis a much better option than--lock-tablesbecause it does not need to lock the tables at all.Because
--lock-tableslocks 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-tablesat the end of the option list.Enclose the
INSERTstatements for each dumped table withinSET autocommit = 0andCOMMITstatements.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
MyISAMtable to be loaded into anInnoDBtable, but makes the dump operation take considerably longer.--shared-memory-base-name=nameOn 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_memorysystem variable enabled to support shared-memory connections.This option sets the transaction isolation mode to
REPEATABLE READand sends aSTART TRANSACTIONSQL 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 TRANSACTIONwas issued without blocking any applications.When using this option, you should keep in mind that only
InnoDBtables are dumped in a consistent state. For example, anyMyISAMorMEMORYtables dumped while using this option may still change state.While a
--single-transactiondump 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 theSELECTthat is performed by mysqldump to retrieve the table contents to obtain incorrect contents or fail.The
--single-transactionoption and the--lock-tablesoption are mutually exclusive becauseLOCK TABLEScauses any pending transactions to be committed implicitly.To dump large tables, combine the
--single-transactionoption with the--quickoption.
Option Groups
The
--optoption turns on several settings that work together to perform a fast dump operation. All of these settings are on by default, because--optis on by default. Thus you rarely if ever specify--opt. Instead, you can turn these settings off as a group by specifying--skip-opt, the optionally re-enable certain settings by specifying the associated options later on the command line.The
--compactoption 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-compactform.
When you selectively enable or disable the effect of a group
option, order is important because options are processed first
to last. For example,
--disable-keys
--lock-tables
--skip-opt would not have the
intended effect; it is the same as
--skip-opt by itself.
Examples
To make a backup of an entire database:
shell> mysqldump db_name > backup-file.sqlTo load the dump file back into the server:
shell> mysql db_name < backup-file.sqlAnother way to reload the dump file:
shell> mysql -e "source /path-to-backup/backup-file.sql" db_namemysqldump is also very useful for populating databases by copying data from one MySQL server to another:
shell> mysqldump --opt db_name | mysql --host=remote_host -C db_nameYou can dump several databases with one command:
shell> mysqldump --databases db_name1 [db_name2 ...] > my_databases.sql
To dump all databases, use the
--all-databases option:
shell> mysqldump --all-databases > all_databases.sql
For InnoDB tables,
mysqldump provides a way of making an online
backup:
shell> mysqldump --all-databases --master-data --single-transaction > all_databases.sql
This backup acquires a global read lock on all tables (using
FLUSH TABLES WITH READ LOCK) at
the beginning of the dump. As soon as this lock has been
acquired, the binary log coordinates are read and the lock is
released. If long updating statements are running when the
FLUSH statement is issued, the
MySQL server may get stalled until those statements finish.
After that, the dump becomes lock free and does not disturb
reads and writes on the tables. If the update statements that
the MySQL server receives are short (in terms of execution
time), the initial lock period should not be noticeable, even
with many updates.
For point-in-time recovery (also known as “roll-forward,” when you need to restore an old backup and replay the changes that happened since that backup), it is often useful to rotate the binary log (see Section 5.4.4, “The Binary Log”) or at least know the binary log coordinates to which the dump corresponds:
shell> mysqldump --all-databases --master-data=2 > all_databases.sqlOr:
shell> mysqldump --all-databases --flush-logs --master-data=2
> all_databases.sql
The --master-data and
--single-transaction options
can be used simultaneously, which provides a convenient way to
make an online backup suitable for use prior to point-in-time
recovery if tables are stored using the
InnoDB storage engine.
For more information on making backups, see Section 7.2, “Database Backup Methods”, and Section 7.3, “Example Backup and Recovery Strategy”.
To select the effect of
--optexcept for some features, use the--skipoption for each feature. To disable extended inserts and memory buffering, use--opt--skip-extended-insert--skip-quick. (Actually,--skip-extended-insert--skip-quickis sufficient because--optis on by default.)To reverse
--optfor all features except index disabling and table locking, use--skip-opt--disable-keys--lock-tables.
Restrictions
mysqldump does not dump the
INFORMATION_SCHEMA,
performance_schema, or sys
schema by default. To dump any of these, name them explicitly on
the command line. You can also name them with the
--databases option. For
INFORMATION_SCHEMA and
performance_schema, also use the
--skip-lock-tables
option.
mysqldump does not dump the NDB Cluster
ndbinfo information database.
mysqldump does not dump
InnoDB CREATE
TABLESPACE statements.
It is not recommended to restore from a dump made using mysqldump to a MySQL 5.6.9 or earlier server that has GTIDs enabled. See Section 16.1.3.6, “Restrictions on Replication with GTIDs”.
mysqldump includes statements to recreate the
general_log and
slow_query_log tables for dumps of the
mysql database. Log table contents are not
dumped.
If you encounter problems backing up views due to insufficient privileges, see Section 23.9, “Restrictions on Views” for a workaround.