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MYSQLDUMP(1) MySQL Database System MYSQLDUMP(1)
NAME
mysqldump - a database backup program
SYNOPSIS
mysqldump [options] [db_name [tbl_name ...]]
DESCRIPTION
The mysqldump client utility performs logical backups, producing a set of SQL statements
that can be executed to reproduce the original database object definitions and table data.
It dumps one or more MySQL databases for backup or transfer to another SQL server. The
mysqldump command can also generate output in CSV, other delimited text, or XML format.
o Performance and Scalability Considerations
o Invocation Syntax
o Option Syntax - Alphabetical Summary
o Connection Options
o Option-File Options
o DDL Options
o Debug Options
o Help Options
o Internationalization Options
o Replication Options
o Format Options
o Filtering Options
o Performance Options
o Transactional Options
o Option Groups
o Examples
o Restrictions
Note
If you have tables that contain generated columns, use the mysqldump utility provided
with MySQL 5.7.9 or higher to create your dump files. The mysqldump utility provided
in earlier releases uses incorrect syntax for generated column definitions (Bug
#20769542). You can use the INFORMATION_SCHEMA.COLUMNS table to identify tables with
generated columns.
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.
Note
A dump made using PowerShell on Windows with output redirection creates a file that
has UTF-16 encoding:
shell> mysqldump [options] > dump.sql
However, UTF-16 is not permitted as a connection character set (see Section 10.4,
"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
Performance and Scalability Considerations.PP 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:
o If your tables are primarily InnoDB tables, or if you have a mix of InnoDB and MyISAM
tables, consider using the mysqlbackup command of the MySQL Enterprise Backup product.
(Available as part of the Enterprise subscription.) It provides the best performance
for InnoDB backups with minimal disruption; it can also back up tables from MyISAM and
other storage engines; and it provides a number of convenient options to accommodate
different backup scenarios. See Section 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.PP 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.PP 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 4.2.6, "Using Option Files". Connection Options.PP 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.
o --bind-address=ip_address
On a computer having multiple network interfaces, use this option to select which
interface to use for connecting to the MySQL server.
o --compress, -C
Compress all information sent between the client and the server if both support
compression.
o --default-auth=plugin
A hint about the client-side authentication plugin to use. See Section 6.3.9,
"Pluggable Authentication".
o --enable-cleartext-plugin
Enable the mysql_clear_password cleartext authentication plugin. (See Section 6.5.1.6,
"Client-Side Cleartext Pluggable Authentication".)
This option was added in MySQL 5.7.10.
o --get-server-public-key
Request from the server the public key required for RSA key pair-based password
exchange. This option applies to clients that that authenticate with the
caching_sha2_password authentication plugin. For that plugin, the server does not send
the public key unless requested. This option is ignored for accounts that do not
authenticate with that plugin. It is also ignored if RSA-based password exchange is
not used, as is the case when the client connects to the server using a secure
connection.
If --server-public-key-path=file_name is given and specifies a valid public key file,
it takes precedence over --get-server-public-key.
For information about the caching_sha2_password plugin, see Section 6.5.1.5, "Caching
SHA-2 Pluggable Authentication".
The --get-server-public-key option was added in MySQL 5.7.23.
o --host=host_name, -h host_name
Dump data from the MySQL server on the given host. The default host is localhost.
o --login-path=name
Read options from the named login path in the .mylogin.cnf login path file. A "login
path" is an option group containing options that specify which MySQL server to connect
to and which account to authenticate as. To create or modify a login path file, use
the mysql_config_editor utility. See mysql_config_editor(1).
o --password[=password], -p[password]
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
password value following the --password or -p option on the command line, mysqldump
prompts for one.
Specifying a password on the command line should be considered insecure. See
Section 6.1.2.1, "End-User Guidelines for Password Security". You can use an option
file to avoid giving the password on the command line.
o --pipe, -W
On Windows, connect to the server using a named pipe. This option applies only if the
server supports named-pipe connections.
o --plugin-dir=dir_name
The directory in which to look for plugins. Specify this option if the --default-auth
option is used to specify an authentication plugin but mysqldump does not find it. See
Section 6.3.9, "Pluggable Authentication".
o --port=port_num, -P port_num
The TCP/IP port number to use for the connection.
o --protocol={TCP|SOCKET|PIPE|MEMORY}
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".
o --secure-auth
Do not send passwords to the server in old (pre-4.1) format. This prevents connections
except for servers that use the newer password format.
As of MySQL 5.7.5, this option is deprecated 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.
Note
Passwords that use the pre-4.1 hashing method are less secure than passwords that
use the native password hashing method and should be avoided. Pre-4.1 passwords
are deprecated and support for them was removed in MySQL 5.7.5. For account
upgrade instructions, see Section 6.5.1.3, "Migrating Away from Pre-4.1 Password
Hashing and the mysql_old_password Plugin".
o --server-public-key-path=file_name
The 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_password or
caching_sha2_password authentication plugin. This option is ignored for accounts that
do not authenticate with one of those plugins. It is also ignored if RSA-based
password exchange is not used, as is the case when the client connects to the server
using a secure connection.
If --server-public-key-path=file_name is given and specifies a valid public key file,
it takes precedence over --get-server-public-key.
For sha256_password, this option applies only if MySQL was built using OpenSSL.
For information about the sha256_password and caching_sha2_password plugins, see
Section 6.5.1.4, "SHA-256 Pluggable Authentication", and Section 6.5.1.5, "Caching
SHA-2 Pluggable Authentication".
The --server-public-key-path option was added in MySQL 5.7.23.
o --socket=path, -S path
For connections to localhost, the Unix socket file to use, or, on Windows, the name of
the named pipe to use.
o --ssl*
Options that begin with --ssl specify whether to connect to the server using SSL and
indicate where to find SSL keys and certificates. See Section 6.4.2, "Command Options
for Encrypted Connections".
o --tls-version=protocol_list
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 6.4.6, "Encrypted Connection Protocols and Ciphers".
This option was added in MySQL 5.7.10.
o --user=user_name, -u user_name
The MySQL user name to use when connecting to the server.
You can also set the following variables by using --var_name=value syntax:
o max_allowed_packet
The maximum size of the buffer for client/server communication. The default is 24MB,
the maximum is 1GB.
o net_buffer_length
The initial size of the buffer for client/server communication. When creating
multiple-row INSERT statements (as with the --extended-insert or --opt option),
mysqldump creates rows up to net_buffer_length bytes long. If you increase this
variable, ensure that the MySQL server net_buffer_length system variable has a value
at least this large.
Option-File Options.PP These options are used to control which option files to read.
o --defaults-extra-file=file_name
Read this option file after the global option file but (on Unix) before the user
option file. If the file does not exist or is otherwise inaccessible, an error occurs.
file_name is interpreted relative to the current directory if given as a relative path
name rather than a full path name.
o --defaults-file=file_name
Use only the given option file. If the file does not exist or is otherwise
inaccessible, an error occurs. file_name is interpreted relative to the current
directory if given as a relative path name rather than a full path name.
Exception: Even with --defaults-file, client programs read .mylogin.cnf.
o --defaults-group-suffix=str
Read not only the usual option groups, but also groups with the usual names and a
suffix of str. For example, mysqldump normally reads the [client] and [mysqldump]
groups. If the --defaults-group-suffix=_other option is given, mysqldump also reads
the [client_other] and [mysqldump_other] groups.
o --no-defaults
Do not read any option files. If program startup fails due to reading unknown options
from an option file, --no-defaults can be used to prevent them from being read.
The exception is that the .mylogin.cnf file, if it exists, is read in all cases. This
permits passwords to be specified in a safer way than on the command line even when
--no-defaults is used. (.mylogin.cnf is created by the mysql_config_editor utility.
See mysql_config_editor(1).)
o --print-defaults
Print the program name and all options that it gets from option files.
DDL Options.PP 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.
o --add-drop-database
Write a DROP DATABASE statement before each CREATE DATABASE statement. This option is
typically used in conjunction with the --all-databases or --databases option because
no CREATE DATABASE statements are written unless one of those options is specified.
o --add-drop-table
Write a DROP TABLE statement before each CREATE TABLE statement.
o --add-drop-trigger
Write a DROP TRIGGER statement before each CREATE TRIGGER statement.
o --all-tablespaces, -Y
Adds to a table dump all SQL statements needed to create any tablespaces used by an
NDB table. This information is not otherwise included in the output from mysqldump.
This option is currently relevant only to NDB Cluster tables, which are not supported
in MySQL 5.7.
o --no-create-db, -n
Suppress the CREATE DATABASE statements that are otherwise included in the output if
the --databases or --all-databases option is given.
o --no-create-info, -t
Do not write CREATE TABLE statements that create each dumped table.
Note
This option does not exclude statements creating log file groups or tablespaces
from mysqldump output; however, you can use the --no-tablespaces option for this
purpose.
o --no-tablespaces, -y
This option suppresses all CREATE LOGFILE GROUP and CREATE TABLESPACE statements in
the output of mysqldump.
o --replace
Write REPLACE statements rather than INSERT statements.
Debug Options.PP The following options print debugging information, encode debugging
information in the dump file, or let the dump operation proceed regardless of potential
problems.
o --allow-keywords
Permit creation of column names that are keywords. This works by prefixing each column
name with the table name.
o --comments, -i
Write additional information in the dump file such as program version, server version,
and host. This option is enabled by default. To suppress this additional information,
use --skip-comments.
o --debug[=debug_options], -# [debug_options]
Write a debugging log. A typical debug_options string is d:t:o,file_name. The default
value is d:t:o,/tmp/mysqldump.trace.
o --debug-check
Print some debugging information when the program exits.
o --debug-info
Print debugging information and memory and CPU usage statistics when the program
exits.
o --dump-date
If the --comments option is given, mysqldump produces a comment at the end of the dump
of the following form:
-- Dump completed on DATE
However, the date causes dump files taken at different times to appear to be
different, even if the data are otherwise identical. --dump-date and --skip-dump-date
control whether the date is added to the comment. The default is --dump-date (include
the date in the comment). --skip-dump-date suppresses date printing.
o --force, -f
Ignore all errors; continue even if an SQL error occurs during a table dump.
One use for this option is to cause mysqldump to continue executing even when it
encounters a view that has become invalid because the definition refers to a table
that has been dropped. Without --force, mysqldump exits with an error message. With
--force, mysqldump prints the error message, but it also writes an SQL comment
containing the view definition to the dump output and continues executing.
If the --ignore-error option is also given to ignore specific errors, --force takes
precedence.
o --log-error=file_name
Log warnings and errors by appending them to the named file. The default is to do no
logging.
o --skip-comments
See the description for the --comments option.
o --verbose, -v
Verbose mode. Print more information about what the program does.
Help Options.PP The following options display information about the mysqldump command
itself.
o --help, -?
Display a help message and exit.
o --version, -V
Display version information and exit.
Internationalization Options.PP The following options change how the mysqldump command
represents character data with national language settings.
o --character-sets-dir=dir_name
The directory where character sets are installed. See Section 10.14, "Character Set
Configuration".
o --default-character-set=charset_name
Use charset_name as the default character set. See Section 10.14, "Character Set
Configuration". If no character set is specified, mysqldump uses utf8.
o --no-set-names, -N
Turns off the --set-charset setting, the same as specifying --skip-set-charset.
o --set-charset
Write SET NAMES default_character_set to the output. This option is enabled by
default. To suppress the SET NAMES statement, use --skip-set-charset.
Replication Options.PP 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.
o --apply-slave-statements
For a slave dump produced with the --dump-slave option, add a STOP SLAVE statement
before the CHANGE MASTER TO statement and a START SLAVE statement at the end of the
output.
o --delete-master-logs
On a master replication server, delete the binary logs by sending a PURGE BINARY LOGS
statement to the server after performing the dump operation. This option automatically
enables --master-data.
o --dump-slave[=value]
This option is similar to --master-data except that it is used to dump a replication
slave server to produce a dump file that can be used to set up another server as a
slave that has the same master as the dumped server. It causes the dump output to
include a CHANGE MASTER TO statement that indicates the binary log coordinates (file
name and position) of the dumped slave's master. The CHANGE MASTER TO statement reads
the values of Relay_Master_Log_File and Exec_Master_Log_Pos from the SHOW SLAVE STATUS
output and uses them for MASTER_LOG_FILE and MASTER_LOG_POS respectively. These are
the 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 16.4.1.33,
"Replication and Transaction Inconsistencies" for more information.
--dump-slave causes the coordinates from the master to be used rather than those of
the dumped server, as is done by the --master-data option. In addition, specfiying
this option causes the --master-data option to be overridden, if used, and effectively
ignored.
Warning
This option should not be used if the server where the dump is going to be applied
uses gtid_mode=ON and MASTER_AUTOPOSITION=1.
The option value is handled the same way as for --master-data (setting no value or 1
causes a CHANGE MASTER TO statement to be written to the dump, setting 2 causes the
statement to be written but encased in SQL comments) and has the same effect as
--master-data in terms of enabling or disabling other options and in how locking is
handled.
This option causes mysqldump to stop the slave SQL thread before the dump and restart
it again after.
In conjunction with --dump-slave, the --apply-slave-statements and
--include-master-host-port options can also be used.
o --include-master-host-port
For the CHANGE MASTER TO statement in a slave dump produced with the --dump-slave
option, add MASTER_HOST and MASTER_PORT options for the host name and TCP/IP port
number of the slave's master.
o --master-data[=value]
Use this option to dump a master replication server to produce a dump file that can be
used to set up another server as a slave of the master. It causes the dump output to
include a CHANGE MASTER TO statement that indicates the binary log coordinates (file
name and position) of the dumped server. These are the master server coordinates from
which the slave should start replicating after you load the dump file into the slave.
If the option value is 2, the CHANGE MASTER TO statement is written as an SQL comment,
and thus is informative only; it has no effect when the dump file is reloaded. If the
option value is 1, the statement is not written as a comment and takes effect when the
dump file is reloaded. If no option value is specified, the default value is 1.
This option requires the RELOAD privilege and the binary log must be enabled.
The --master-data option automatically turns off --lock-tables. It also turns on
--lock-all-tables, unless --single-transaction also is specified, in which case, a
global read lock is acquired only for a short time at the beginning of the dump (see
the description for --single-transaction). In all cases, any action on logs happens at
the exact moment of the dump.
It is also possible to set up a slave by dumping an existing slave of the master,
using the --dump-slave option, which overrides --master-data and causes it to be
ignored if both options are used.
o --set-gtid-purged=value
This option enables control over global transaction ID (GTID) information written to
the dump file, by indicating whether to add a SET @@global.gtid_purged statement to
the output. This option may also cause a statement to be written to the output that
disables binary logging while the dump file is being reloaded.
The following table shows the permitted option values. The default value is AUTO.
+------+----------------------------------+
|Value | Meaning |
+------+----------------------------------+
|OFF | Add no SET statement to the |
| | output. |
+------+----------------------------------+
|ON | Add a SET statement to the |
| | output. An error occurs if |
| | GTIDs are not |
| | enabled on the server. |
+------+----------------------------------+
|AUTO | Add a SET statement to the |
| | output if GTIDs are |
| | enabled on the |
| | server. |
+------+----------------------------------+
A partial dump from a server that is using GTID-based replication requires the
--set-gtid-purged={ON|OFF} option to be specified. Use ON if the intention is to
deploy a new replication slave using only some of the data from the dumped server. Use
OFF if the intention is to repair a table by copying it within a topology. Use OFF if
the intention is to copy a table between replication topologies that are disjoint and
will remain so.
The --set-gtid-purged option has the following effect on binary logging when the dump
file is reloaded:
o --set-gtid-purged=OFF: SET @@SESSION.SQL_LOG_BIN=0; is not added to the output.
o --set-gtid-purged=ON: SET @@SESSION.SQL_LOG_BIN=0; is added to the output.
o --set-gtid-purged=AUTO: SET @@SESSION.SQL_LOG_BIN=0; is added to the output if
GTIDs are enabled on the server you are backing up (that is, if AUTO evaluates to
ON).
Note
It is not recommended to load a dump file when GTIDs are enabled on the server
(gtid_mode=ON), if your dump file includes system tables. mysqldump issues DML
instructions for the system tables which use the non-transactional MyISAM storage
engine, and this combination is not permitted when GTIDs are enabled. Also be
aware that loading a dump file from a server with GTIDs enabled, into another
server with GTIDs enabled, causes different transaction identifiers to be
generated.
Format Options.PP 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.
o --compact
Produce more compact output. This option enables the --skip-add-drop-table,
--skip-add-locks, --skip-comments, --skip-disable-keys, and --skip-set-charset
options.
o --compatible=name
Produce output that is more compatible with other database systems or with older MySQL
servers. The value of name can be ansi, mysql323, mysql40, postgresql, oracle, mssql,
db2, maxdb, no_key_options, no_table_options, or no_field_options. To use several
values, separate them by commas. These values have the same meaning as the
corresponding options for setting the server SQL mode. See Section 5.1.10, "Server SQL
Modes".
This option does not guarantee compatibility with other servers. It only enables those
SQL mode values that are currently available for making dump output more compatible.
For example, --compatible=oracle does not map data types to Oracle types or use Oracle
comment syntax.
o --complete-insert, -c
Use complete INSERT statements that include column names.
o --create-options
Include all MySQL-specific table options in the CREATE TABLE statements.
o --fields-terminated-by=..., --fields-enclosed-by=...,
--fields-optionally-enclosed-by=..., --fields-escaped-by=...
These options are used with the --tab option and have the same meaning as the
corresponding FIELDS clauses for LOAD DATA INFILE. See Section 13.2.6, "LOAD DATA
INFILE Syntax".
o --hex-blob
Dump binary columns using hexadecimal notation (for example, 'abc' becomes 0x616263).
The affected data types are BINARY, VARBINARY, the BLOB types, and BIT.
o --lines-terminated-by=...
This option is used with the --tab option and has the same meaning as the
corresponding LINES clause for LOAD DATA INFILE. See Section 13.2.6, "LOAD DATA INFILE
Syntax".
o --quote-names, -Q
Quote identifiers (such as database, table, and column names) within ` characters. If
the ANSI_QUOTES SQL mode is enabled, identifiers are quoted within " characters. This
option is enabled by default. It can be disabled with --skip-quote-names, but this
option should be given after any option such as --compatible that may enable
--quote-names.
o --result-file=file_name, -r file_name
Direct output to the named file. The result file is created and its previous contents
overwritten, even if an error occurs while generating the dump.
This option should be used on Windows to prevent newline \n characters from being
converted to \r\n carriage return/newline sequences.
o --tab=dir_name, -T dir_name
Produce tab-separated text-format data files. For each dumped table, mysqldump creates
a tbl_name.sql file that contains the CREATE TABLE statement that creates the table,
and the server writes a tbl_name.txt file that contains its data. The option value is
the directory in which to write the files.
Note
This option should be used only when mysqldump is run on the same machine as the
mysqld server. Because the server creates *.txt files in the directory that you
specify, the directory must be writable by the server and the MySQL account that
you use must have the FILE privilege. Because mysqldump creates *.sql in the same
directory, it must be writable by your system login account.
By default, the .txt data files are formatted using tab characters between column
values and a newline at the end of each line. The format can be specified explicitly
using the --fields-xxx and --lines-terminated-by options.
Column values are converted to the character set specified by the
--default-character-set option.
o --tz-utc
This option enables TIMESTAMP columns to be dumped and reloaded between servers in
different time zones. mysqldump sets its connection time zone to UTC and adds SET
TIME_ZONE='+00:00' to the dump file. Without this option, TIMESTAMP columns are dumped
and reloaded in the time zones local to the source and destination servers, which can
cause the values to change if the servers are in different time zones. --tz-utc also
protects against changes due to daylight saving time. --tz-utc is enabled by default.
To disable it, use --skip-tz-utc.
o --xml, -X
Write dump output as well-formed XML.
NULL, 'NULL', and Empty Values: For a column named column_name, the NULL value, an
empty string, and the string value 'NULL' are distinguished from one another in the
output generated by this option as follows.
+---------------------+--------------------------------------------+
|Value: | XML Representation: |
+---------------------+--------------------------------------------+
|NULL (unknown value) | |
| | <field |
| | name="column_name" |
| | xsi:nil="true" /> |
+---------------------+--------------------------------------------+
| | |
| | <field |
| | name="column_name"></field> |
+---------------------+--------------------------------------------+
| | |
| | <field |
| | name="column_name">NULL</field> |
+---------------------+--------------------------------------------+
The output from the mysql client when run using the --xml option also follows the
preceding rules. (See the section called "MYSQL 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.PP 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.
o --all-databases, -A
Dump all tables in all databases. This is the same as using the --databases option and
naming all the databases on the command line.
o --databases, -B
Dump several databases. Normally, mysqldump treats the first name argument on the
command line as a database name and following names as table names. With this option,
it treats all name arguments as database names. CREATE DATABASE and USE statements
are included in the output before each new database.
This option may be used to dump the INFORMATION_SCHEMA and performace_schema
databases, which normally are not dumped even with the --all-databases option. (Also
use the --skip-lock-tables option.)
o --events, -E
Include Event Scheduler events for the dumped databases in the output. This option
requires the EVENT privileges for those databases.
The output generated by using --events contains CREATE EVENT statements to create the
events. However, these statements do not include attributes such as the event creation
and modification timestamps, so when the events are reloaded, they are created with
timestamps equal to the reload time.
If you require events to be created with their original timestamp attributes, do not
use --events. Instead, dump and reload the contents of the mysql.event table directly,
using a MySQL account that has appropriate privileges for the mysql database.
o --ignore-error=error[,error]...
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 --force
option is also given to ignore all errors, --force takes precedence.
o --ignore-table=db_name.tbl_name
Do not dump the given table, which must be specified using both the database and table
names. To ignore multiple tables, use this option multiple times. This option also can
be used to ignore views.
o --no-data, -d
Do not write any table row information (that is, do not dump table contents). This is
useful if you want to dump only the CREATE TABLE statement for the table (for example,
to create an empty copy of the table by loading the dump file).
o --routines, -R
Include stored routines (procedures and functions) for the dumped databases in the
output. This option requires the SELECT privilege for the mysql.proc table.
The output generated by using --routines contains CREATE PROCEDURE and CREATE FUNCTION
statements to create the routines. However, these statements do not include attributes
such as the routine creation and modification timestamps, so when the routines are
reloaded, they are created with timestamps equal to the reload time.
If you require routines to be created with their original timestamp attributes, do not
use --routines. Instead, dump and reload the contents of the mysql.proc table
directly, using a MySQL account that has appropriate privileges for the mysql
database.
o --tables
Override the --databases or -B option. mysqldump regards all name arguments following
the option as table names.
o --triggers
Include triggers for each dumped table in the output. This option is enabled by
default; disable it with --skip-triggers.
To be able to dump a table's triggers, you must have the TRIGGER privilege for the
table.
Multiple triggers are permitted. mysqldump dumps triggers in activation order so that
when the dump file is reloaded, triggers are created in the same activation order.
However, if a mysqldump dump file contains multiple triggers for a table that have the
same trigger event and action time, an error occurs for attempts to load the dump file
into an older server that does not support multiple triggers. (For a workaround, see
Section 2.11.2.1, "Changes Affecting Downgrades from MySQL 5.7"; you can convert
triggers to be compatible with older servers.)
o --where='where_condition', -w 'where_condition'
Dump only rows selected by the given WHERE condition. Quotes around the condition are
mandatory if it contains spaces or other characters that are special to your command
interpreter.
Examples:
--where="user='jimf'"
-w"userid>1"
-w"userid<1"
Performance Options.PP 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.
o --disable-keys, -K
For each table, surround the INSERT statements with /*!40000 ALTER TABLE tbl_name
DISABLE KEYS */; and /*!40000 ALTER TABLE tbl_name ENABLE KEYS */; statements. This
makes loading the dump file faster because the indexes are created after all rows are
inserted. This option is effective only for nonunique indexes of MyISAM tables.
o --extended-insert, -e
Write INSERT statements using multiple-row syntax that includes several VALUES lists.
This results in a smaller dump file and speeds up inserts when the file is reloaded.
o --insert-ignore
Write INSERT IGNORE statements rather than INSERT statements.
o --opt
This option, enabled by default, is shorthand for the combination of --add-drop-table
--add-locks --create-options --disable-keys --extended-insert --lock-tables --quick
--set-charset. It gives a fast dump operation and produces a dump file that can be
reloaded into a MySQL server quickly.
Because the --opt option is enabled by default, you only specify its converse, the
--skip-opt to turn off several default settings. See the discussion of mysqldump
option groups for information about selectively enabling or disabling a subset of the
options affected by --opt.
o --quick, -q
This option is useful for dumping large tables. It forces mysqldump to retrieve rows
for a table from the server a row at a time rather than retrieving the entire row set
and buffering it in memory before writing it out.
o --skip-opt
See the description for the --opt option.
Transactional Options.PP The following options trade off the performance of the dump
operation, against the reliability and consistency of the exported data.
o --add-locks
Surround each table dump with LOCK TABLES and UNLOCK TABLES statements. This results
in faster inserts when the dump file is reloaded. See Section 8.2.4.1, "Optimizing
INSERT Statements".
o --flush-logs, -F
Flush the MySQL server log files before starting the dump. This option requires the
RELOAD privilege. If you use this option in combination with the --all-databases
option, the logs are flushed for each database dumped. The exception is when using
--lock-all-tables, --master-data, or --single-transaction: In this case, the logs are
flushed only once, corresponding to the moment that all tables are locked by FLUSH
TABLES WITH READ LOCK. If you want your dump and the log flush to happen at exactly
the same moment, you should use --flush-logs together with --lock-all-tables,
--master-data, or --single-transaction.
o --flush-privileges
Add a FLUSH PRIVILEGES statement to the dump output after dumping the mysql database.
This option should be used any time the dump contains the mysql database and any other
database that depends on the data in the mysql database for proper restoration.
Note
For upgrades to MySQL 5.7 or higher from older versions, do not use
--flush-privileges. For upgrade instructions in this case, see Section 2.11.1.2,
"Changes Affecting Upgrades to MySQL 5.7".
o --lock-all-tables, -x
Lock all tables across all databases. This is achieved by acquiring a global read lock
for the duration of the whole dump. This option automatically turns off
--single-transaction and --lock-tables.
o --lock-tables, -l
For each dumped database, lock all tables to be dumped before dumping them. The tables
are locked with READ LOCAL to permit concurrent inserts in the case of MyISAM tables.
For transactional tables such as InnoDB, --single-transaction is a much better option
than --lock-tables because it does not need to lock the tables at all.
Because --lock-tables locks tables for each database separately, this option does not
guarantee that the tables in the dump file are logically consistent between databases.
Tables in different databases may be dumped in completely different states.
Some options, such as --opt, automatically enable --lock-tables. If you want to
override this, use --skip-lock-tables at the end of the option list.
o --no-autocommit
Enclose the INSERT statements for each dumped table within SET autocommit = 0 and
COMMIT statements.
o --order-by-primary
Dump each table's rows sorted by its primary key, or by its first unique index, if
such an index exists. This is useful when dumping a MyISAM table to be loaded into an
InnoDB table, but makes the dump operation take considerably longer.
o --shared-memory-base-name=name
On Windows, the shared-memory name to use, for connections made using shared memory to
a local server. The default value is MYSQL. The shared-memory name is case-sensitive.
The server must be started with the --shared-memory option to enable shared-memory
connections.
o --single-transaction
This option sets the transaction isolation mode to REPEATABLE READ and sends a START
TRANSACTION SQL statement to the server before dumping data. It is useful only with
transactional tables such as InnoDB, because then it dumps the consistent state of the
database at the time when START TRANSACTION was issued without blocking any
applications.
When using this option, you should keep in mind that only InnoDB tables are dumped in
a consistent state. For example, any MyISAM or MEMORY tables dumped while using this
option may still change state.
While a --single-transaction dump is in process, to ensure a valid dump file (correct
table contents and binary log coordinates), no other connection should use the
following statements: ALTER TABLE, CREATE TABLE, DROP TABLE, RENAME TABLE, TRUNCATE
TABLE. A consistent read is not isolated from those statements, so use of them on a
table to be dumped can cause the SELECT that is performed by mysqldump to retrieve the
table contents to obtain incorrect contents or fail.
The --single-transaction option and the --lock-tables option are mutually exclusive
because LOCK TABLES causes any pending transactions to be committed implicitly.
To dump large tables, combine the --single-transaction option with the --quick option.
Option Groups
o The --opt option turns on several settings that work together to perform a fast dump
operation. All of these settings are on by default, because --opt is on by default.
Thus you rarely if ever specify --opt. Instead, you can turn these settings off as a
group by specifying --skip-opt, the optionally re-enable certain settings by
specifying the associated options later on the command line.
o The --compact option turns off several settings that control whether optional
statements and comments appear in the output. Again, you can follow this option with
other options that re-enable certain settings, or turn all the settings on by using
the --skip-compact form.
When you selectively enable or disable the effect of a group option, order is important
because options are processed first to last. For example, --disable-keys --lock-tables
--skip-opt would not have the intended effect; it is the same as --skip-opt by itself.
Examples.PP To make a backup of an entire database:
shell> mysqldump db_name > backup-file.sql
To load the dump file back into the server:
shell> mysql db_name < backup-file.sql
Another way to reload the dump file:
shell> mysql -e "source /path-to-backup/backup-file.sql" db_name
mysqldump is also very useful for populating databases by copying data from one MySQL
server to another:
shell> mysqldump --opt db_name | mysql --host=remote_host -C db_name
You can dump several databases with one command:
shell> mysqldump --databases db_name1 [db_name2 ...] > my_databases.sql
To dump all databases, use the --all-databases option:
shell> mysqldump --all-databases > all_databases.sql
For InnoDB tables, mysqldump provides a way of making an online backup:
shell> mysqldump --all-databases --master-data --single-transaction > all_databases.sql
This backup acquires a global read lock on all tables (using FLUSH TABLES WITH READ LOCK)
at the beginning of the dump. As soon as this lock has been acquired, the binary log
coordinates are read and the lock is released. If long updating statements are running
when the FLUSH statement is issued, the MySQL server may get stalled until those
statements finish. After that, the dump becomes lock free and does not disturb reads and
writes on the tables. If the update statements that the MySQL server receives are short
(in terms of execution time), the initial lock period should not be noticeable, even with
many updates.
For point-in-time recovery (also known as "roll-forward," when you need to restore an old
backup and replay the changes that happened since that backup), it is often useful to
rotate the binary log (see Section 5.4.4, "The Binary Log") or at least know the binary
log coordinates to which the dump corresponds:
shell> mysqldump --all-databases --master-data=2 > all_databases.sql
Or:
shell> mysqldump --all-databases --flush-logs --master-data=2
> all_databases.sql
The --master-data and --single-transaction options can be used simultaneously, which
provides a convenient way to make an online backup suitable for use prior to point-in-time
recovery if tables are stored using the InnoDB storage engine.
For more information on making backups, see Section 7.2, "Database Backup Methods", and
Section 7.3, "Example Backup and Recovery Strategy".
o To select the effect of --opt except for some features, use the --skip option for each
feature. To disable extended inserts and memory buffering, use --opt
--skip-extended-insert --skip-quick. (Actually, --skip-extended-insert --skip-quick is
sufficient because --opt is on by default.)
o To reverse --opt for all features except index disabling and table locking, use
--skip-opt --disable-keys --lock-tables.
Restrictions.PP 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.
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 16.1.3.4, "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 C.5, "Restrictions on Views" for a workaround.
COPYRIGHT
Copyright (C) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
This documentation is free software; you can redistribute it and/or modify it only under
the terms of the GNU General Public License as published by the Free Software Foundation;
version 2 of the License.
This documentation is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with the program;
if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301 USA or see http://www.gnu.org/licenses/.
SEE ALSO
For more information, please refer to the MySQL Reference Manual, which may already be
installed locally and which is also available online at http://dev.mysql.com/doc/.
AUTHOR
Oracle Corporation (http://dev.mysql.com/).
MySQL 5.7 06/07/2018 MYSQLDUMP(1)
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