Pre-General Availability Draft: 2017-07-27
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
SHOW VIEW for dumped
TRIGGER for dumped
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
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
A dump made using PowerShell on Windows with output redirection creates a file that has UTF-16 encoding:
shell> mysqldump [options] > dump.sql
However, UTF-16 is not permitted as a connection character set
(see Section 10.1.4, “Connection Character Sets and Collations”), so the dump file
will not load correctly. To work around this issue, use the
--result-file option, which creates the
output in ASCII format:
shell> mysqldump [options] --result-file=dump.sql
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 of
MyISAMtables, consider using the mysqlbackup command of the MySQL Enterprise Backup product. (Available as part of the Enterprise subscription.) It provides the best performance for
InnoDBbackups with minimal disruption; it can also back up tables from
MyISAMand 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
--opt option (and hence
--quick) is enabled by
default, so to enable memory buffering, use
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
mysqldump supports the following options,
which can be specified on the command line or in the
groups of an option file. For information about option files
used by MySQL programs, see Section 4.2.6, “Using Option Files”.
|--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|
|--column-statistics||Write ANALYZE TABLE statements to generate statistics histograms||8.0.2|
|--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|
|--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 INFILE|
|--fields-escaped-by||This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE|
|--fields-optionally-enclosed-by||This option is used with the --tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE|
|--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|
|--help||Display help message and exit|
|--hex-blob||Dump binary columns using hexadecimal notation|
|--host||Host to connect to (IP address or hostname)|
|--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|
|--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|
|--network-timeout||Increase network timeouts to permit larger table dumps||8.0.1|
|--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||On Windows, connect to server using named pipe|
|--plugin-dir||Directory where plugins are installed|
|--port||TCP/IP port number to use 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||8.0.3|
|--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||The 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||For connections to localhost, the Unix socket file to use|
|--ssl-ca||Path of file that contains list of trusted SSL CAs|
|--ssl-capath||Path of directory that contains trusted SSL CA certificates in PEM format|
|--ssl-cert||Path of file that contains X509 certificate in PEM format|
|--ssl-cipher||List of permitted ciphers to use for connection encryption|
|--ssl-crl||Path of file that contains certificate revocation lists|
|--ssl-crlpath||Path of directory that contains certificate revocation list files|
|--ssl-key||Path of file that contains X509 key in PEM format|
|--ssl-mode||Security state of connection to server|
|--tab||Produce tab-separated data files|
|--tables||Override --databases or -B option|
|--tls-version||Protocols permitted for secure connections|
|--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|
|--version||Display version information and exit|
|--where||Dump only rows selected by given WHERE condition|
|--xml||Produce XML output|
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 both support compression.
A hint about the client-side authentication plugin to use. See Section 6.3.10, “Pluggable Authentication”.
mysql_clear_passwordcleartext authentication plugin. (See Section 126.96.36.199, “Client-Side Cleartext Pluggable Authentication”.)
Dump data from the MySQL server on the given host. The default host is
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 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.
Enable large tables to be dumped by setting
max_allowed_packetto its maximum value and network read and write timeouts to a large value. This option is enabled by default. To disable it, use
The password to use when connecting to the server. If you use the short option form (
-p), you cannot have a space between the option and the password. If you omit the
passwordvalue following the
-poption on the command line, mysqldump prompts for one.
Specifying a password on the command line should be considered insecure. See Section 188.8.131.52, “End-User Guidelines for Password Security”. You can use an option file to avoid giving the password on the command line.
On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections.
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 6.3.10, “Pluggable Authentication”.
The TCP/IP port number to use for the connection.
The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see Section 4.2.2, “Connecting to the MySQL Server”.
This option was removed in MySQL 8.0.3.
For connections to
localhost, the Unix socket file to use, or, on Windows, the name of the named pipe to use.
Options that begin with
--sslspecify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See Section 6.4.5, “Command Options for Secure Connections”.
The protocols permitted by the client for encrypted connections. The value is a comma-separated list containing one or more protocol names. The protocols that can be named for this option depend on the SSL library used to compile MySQL. For details, see Section 6.4.3, “Secure Connection Protocols and Ciphers”.
The MySQL user name to use when connecting to the server.
You can also set the following variables by using
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
--optoption), mysqldump creates rows up to
net_buffer_lengthbytes long. If you increase this variable, ensure that the MySQL server
net_buffer_lengthsystem variable has a value at least this large.
These options are used to control which option files to read.
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_nameis interpreted relative to the current directory if given as a relative path name rather than a full path name.
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
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
[mysqldump]groups. If the
--defaults-group-suffix=_otheroption is given, mysqldump also reads the
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 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.)
Print the program name and all options that it gets from option files.
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.
DROP DATABASEstatement before each
CREATE DATABASEstatement. This option is typically used in conjunction with the
--databasesoption because no
CREATE DATABASEstatements are written unless one of those options is specified.
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 MySQL Cluster tables, which are not supported in MySQL 8.0.
Do not write
CREATE TABLEstatements that create each dumped table.
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
Write a debugging log. A typical
d:t:o,. The default value is
Print some debugging information when the program exits.
Print debugging information and memory and CPU usage statistics when the program exits.
-- 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.
--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.
Log warnings and errors by appending them to the named file. The default is to do no logging.
See the description for the
Verbose mode. Print more information about what the program does.
The following options display information about the mysqldump command itself.
The following options change how the mysqldump command represents character data with national language settings.
The directory where character sets are installed. See Section 10.5, “Character Set Configuration”.
Turns off the
--set-charsetsetting, the same as specifying
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.
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 a
CHANGE MASTER TOstatement that indicates the binary log coordinates (file name and position) of the dumped slave's master. The
CHANGE MASTER TOstatement reads the values of
SHOW SLAVE STATUSoutput and uses them for
MASTER_LOG_POSrespectively. These are the master server coordinates from which the slave should start replicating.Note
Inconsistencies in the sequence of transactions from the relay log which have been executed can cause the wrong position to be used. See Section 184.108.40.206, “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.Warning
This option should not be used if the server where the dump is going to be applied uses
The option value is handled the same way as for
--master-data(setting no value or 1 causes a
CHANGE 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.
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.
--master-dataoption automatically turns off
--lock-tables. It also turns on
--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
SETstatement to the output.
SETstatement to the output. An error occurs if GTIDs are not enabled on the server.
SETstatement to the output if GTIDs are enabled on the server.
--set-gtid-purgedoption has the following effect on binary logging when the dump file is reloaded:
SET @@SESSION.SQL_LOG_BIN=0;is not added to the output.
SET @@SESSION.SQL_LOG_BIN=0;is added to the output.
SET @@SESSION.SQL_LOG_BIN=0;is added to the output if GTIDs are enabled on the server you are backing up (that is, if
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 output that is more compatible with other database systems or with older MySQL servers. The value of
no_field_options. To use several values, separate them by commas. These values have the same meaning as the corresponding options for setting the server SQL mode. See Section 5.1.8, “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.
This option requires a server version of 4.1.0 or higher. With older servers, it does nothing.
INSERTstatements that include column names.
Include all MySQL-specific table options in the
Quote identifiers (such as database, table, and column names) within
`characters. If the
ANSI_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
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
\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 the
CREATE TABLEstatement 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.
This 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 the
FILEprivilege. 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
Column values are converted to the character set specified by the
This option enables
TIMESTAMPcolumns to be dumped and reloaded between servers in different time zones. mysqldump sets its connection time zone to UTC and adds
SET TIME_ZONE='+00:00'to the dump file. Without this option,
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
Write dump output as well-formed XML.
'NULL', and Empty Values: For a column named
NULLvalue, 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:
column_name" xsi:nil="true" />
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>
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
Dump all tables in all databases. This is the same as using the
--databasesoption and naming all the databases on the command line.
Prior to MySQL 8.0, the
--eventsoptions for mysqldump and mysqlpump were not required to include stored routines and events when using the
--all-databasesoption: The dump included the
mysqlsystem database, and therefore also the
mysql.eventtables containing stored routine and event definitions. As of MySQL 8.0, the
mysql.proctables are not used. Definitions for the corresponding objects are stored in data dictionary tables, but those tables are not dumped. To include stored routines and events in a dump made using
--all-databases, use the
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.
USEstatements are included in the output before each new database.
Include Event Scheduler events for the dumped databases in the output. This option requires the
EVENTprivileges for those databases.
The output generated by using
CREATE EVENTstatements to create the events.
Ignore the specified errors. The option value is a comma-separated list of error numbers specifying the errors to ignore during mysqldump execution. If the
--forceoption is also given to ignore all errors,
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 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 global
Include triggers for each dumped table in the output. This option is enabled by default; disable it with
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 220.127.116.11, “Changes Affecting Downgrades from MySQL 8.0”; you can convert triggers to be compatible with older servers.)
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.
--where="user='jimf'" -w"userid>1" -w"userid<1"
The following options are the most relevant for the performance
particularly of the restore operations. For large data sets,
restore operation (processing the
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
Performance is also affected by the transactional options, primarily for the dump operation.
ANALYZE TABLEstatements to the output to generate histogram statistics for dumped tables when the dump file is reloaded. This option is disabled by default because histogram generation for large tables can take a long time.
For each table, surround the
/*!40000 ALTER TABLEand
tbl_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 of
tbl_nameENABLE KEYS */;
INSERTstatements using multiple-row syntax that includes several
VALUESlists. This results in a smaller dump file and speeds up inserts when the file is reloaded.
This option, enabled by default, is shorthand for the combination of
--set-charset. It gives a fast dump operation and produces a dump file that can be reloaded into a MySQL server quickly.
--optoption is enabled by default, you only specify its converse, the
--skip-optto turn off several default settings. See the discussion of
mysqldumpoption groups for information about selectively enabling or disabling a subset of the options affected by
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
The following options trade off the performance of the dump operation, against the reliability and consistency of the exported data.
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
--single-transaction: In this case, the logs are flushed only once, corresponding to the moment that all tables are locked by
FLUSH TABLES WITH READ LOCK. If you want your dump and the log flush to happen at exactly the same moment, you should use
FLUSH PRIVILEGESstatement to the dump output after dumping the
mysqldatabase. This option should be used any time the dump contains the
mysqldatabase and any other database that depends on the data in the
mysqldatabase for proper restoration.Note
For upgrades to MySQL 5.7.2 or higher from older versions, do not use
--flush-privileges. For upgrade instructions in this case, see Section 18.104.22.168, “Changes Affecting Upgrades to MySQL 8.0”.
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 of
MyISAMtables. For transactional tables such as
--single-transactionis a much better option than
--lock-tablesbecause it does not need to lock the tables at all.
--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.
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 an
InnoDBtable, but makes the dump operation take considerably longer.
On Windows, the shared-memory name to use, for connections made using shared memory to a local server. The default value is
MYSQL. The shared-memory name is case sensitive.
The server must be started with the
--shared-memoryoption to enable shared-memory connections.
This option sets the transaction isolation mode to
REPEATABLE READand sends a
START TRANSACTIONSQL statement to the server before dumping data. It is useful only with transactional tables such as
InnoDB, because then it dumps the consistent state of the database at the time when
START 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, any
MEMORYtables dumped while using this option may still change state.
--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:
TRUNCATE TABLE. A consistent read is not isolated from those statements, so use of them on a table to be dumped can cause the
SELECTthat is performed by mysqldump to retrieve the table contents to obtain incorrect contents or fail.
To dump large tables, combine the
--single-transactionoption with 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.
--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
When you selectively enable or disable the effect of a group
option, order is important because options are processed first
to last. For example,
--skip-opt would not have the
intended effect; it is the same as
--skip-opt by itself.
To make a backup of an entire database:
shell> mysqldump db_name > backup-file.sql
To load the dump file back into the server:
shell> mysql db_name < backup-file.sql
Another way to reload the dump file:
shell> mysql -e "source /path-to-backup/backup-file.sql" db_name
mysqldump is also very useful for populating databases by copying data from one MySQL server to another:
shell> mysqldump --opt db_name | mysql --host=remote_host -C db_name
You can dump several databases with one command:
shell> mysqldump --databases db_name1 [db_name2 ...] > my_databases.sql
To dump all databases, use the
shell> mysqldump --all-databases > all_databases.sql
mysqldump provides a way of making an online
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
FLUSH statement is
issued, the MySQL server may get stalled until those statements
finish. After that, the dump becomes lock free and does not
disturb reads and writes on the tables. If the update statements
that the MySQL server receives are short (in terms of execution
time), the initial lock period should not be noticeable, even
with many updates.
For point-in-time recovery (also known as “roll-forward,” when you need to restore an old backup and replay the changes that happened since that backup), it is often useful to rotate the binary log (see Section 5.4.4, “The Binary Log”) or at least know the binary log coordinates to which the dump corresponds:
shell> mysqldump --all-databases --master-data=2 > all_databases.sql
shell> mysqldump --all-databases --flush-logs --master-data=2 > all_databases.sql
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
--skip-quickis sufficient because
--optis on by default.)
mysqldump does not dump the
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
performance_schema, also use the
mysqldump does not dump the
mysqldump includes statements to recreate the
slow_query_log tables for dumps of the
mysql database. Log table contents are not
If you encounter problems backing up views due to insufficient privileges, see Section C.5, “Restrictions on Views” for a workaround.