MYSQLDUMP(1) MySQL Database System MYSQLDUMP(1)
NAME
mysqldump - a database backup program
SYNOPSIS
mysqldump [options] [db_name [tbl_name ...]]
DESCRIPTION
The mysqldump client is a backup program originally written by Igor Romanenko. It can be used to dump a
database or a collection of databases for backup or transfer to another SQL server (not necessarily a MySQL
server). The dump typically contains SQL statements to create the table, populate it, or both. However,
mysqldump can also be used to generate files in CSV, other delimited text, or XML format.
If you are doing a backup on the server and your tables all are MyISAM tables, consider using the mysqlhotcopy
instead because it can accomplish faster backups and faster restores. See mysqlhotcopy(1).
There are three general ways to invoke mysqldump:
shell> mysqldump [options] db_name [tbl_name ...]
shell> mysqldump [options] --databases db_name ...
shell> mysqldump [options] --all-databases
If you do not name any tables following db_name or if you use the --databases or --all-databases option,
entire databases are dumped.
mysqldump does not dump the INFORMATION_SCHEMA database by default. As of MySQL 5.1.38, mysqldump dumps
INFORMATION_SCHEMA if you name it explicitly on the command line, although currently you must also use the
--skip-lock-tables option. Before 5.1.38, mysqldump silently ignores INFORMATION_SCHEMA even if you name it
explicitly on the command line.
To see a list of the options your version of mysqldump supports, execute mysqldump --help.
Some mysqldump options are shorthand for groups of other options:
· Use of --opt is the same as specifying --add-drop-table, --add-locks, --create-options, --disable-keys,
--extended-insert, --lock-tables, --quick, and --set-charset. All of the options that --opt stands for
also are on by default because --opt is on by default.
· Use of --compact is the same as specifying --skip-add-drop-table, --skip-add-locks, --skip-comments,
--skip-disable-keys, and --skip-set-charset options.
To reverse the effect of a group option, uses its --skip-xxx form (--skip-opt or --skip-compact). It is also
possible to select only part of the effect of a group option by following it with options that enable or
disable specific features. Here are some examples:
· To select the effect of --opt except for some features, use the --skip option for each feature. To disable
extended inserts and memory buffering, use --opt --skip-extended-insert --skip-quick. (Actually,
--skip-extended-insert --skip-quick is sufficient because --opt is on by default.)
· To reverse --opt for all features except index disabling and table locking, use --skip-opt --disable-keys
--lock-tables.
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.
mysqldump can retrieve and dump table contents row by row, or it can retrieve the entire content from a table
[client] option file groups. mysqldump also supports the options for processing option files described at
Section 4.2.3.3.1, “Command-Line Options that Affect Option-File Handling”.
· --help, -?
Display a help message and exit.
· --add-drop-database
Add 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.
· --add-drop-table
Add a DROP TABLE statement before each CREATE TABLE statement.
· --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 7.2.21, “Speed of INSERT Statements”.
· --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.
· --all-tablespaces, -Y
Adds to a table dump all SQL statements needed to create any tablespaces used by an NDBCLUSTER table. This
information is not otherwise included in the output from mysqldump. This option is currently relevant only
to MySQL Cluster tables.
This option was added in MySQL 5.1.6.
· --allow-keywords
Allow creation of column names that are keywords. This works by prefixing each column name with the table
name.
· --character-sets-dir=path
The directory where character sets are installed. See Section 9.5, “Character Set Configuration”.
· --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.
· --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.
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.
This option requires a server version of 4.1.0 or higher. With older servers, it does nothing.
· --complete-insert, -c
Use complete INSERT statements that include column names.
· --compress, -C
Compress all information sent between the client and the server if both support compression.
· --create-options, -a
Include all MySQL-specific table options in the CREATE TABLE statements.
· --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.
· --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´.
· --debug-check
Print some debugging information when the program exits. This option was added in MySQL 5.1.21.
· --debug-info
Print debugging information and memory and CPU usage statistics when the program exits. This option was
added in MySQL 5.1.14.
· --default-character-set=charset_name
Use charset_name as the default character set. See Section 9.5, “Character Set Configuration”. If no
character set is specified, mysqldump uses utf8, and earlier versions use latin1.
Prior to MySQL 5.1.38, this option has no effect for output data files produced by using the --tab option.
See the description for that option.
· --defaults-extra-file=filename
Set filename as the file to read default options from after the global defaults files has been read. Must
be given as first option.
· --defaults-file=filename
· --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.
· --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. This option was added in MySQL 5.1.23.
· --events, -E
Include Event Scheduler events for the dumped databases in the output. This option was added in MySQL
5.1.8.
· --extended-insert, -e
Use multiple-row INSERT syntax that include several VALUES lists. This results in a smaller dump file and
speeds up inserts when the file is reloaded.
· --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 12.2.6, “LOAD DATA INFILE Syntax”.
· --first-slave
Deprecated. Use --lock-all-tables instead. --first-slave is removed in MySQL 5.5.
· --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 or --master-data: In this case, the logs are flushed
only once, corresponding to the moment that all tables are locked. If you want your dump and the log flush
to happen at exactly the same moment, you should use --flush-logs together with either --lock-all-tables
or --master-data.
· --flush-privileges
Send a FLUSH PRIVILEGES statement to the server 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. This option was added in MySQL 5.1.12.
Dump data from the MySQL server on the given host. The default host is localhost.
· --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.
· --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.
· --insert-ignore
Write INSERT IGNORE statements rather than INSERT statements.
· --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 12.2.6, “LOAD DATA INFILE Syntax”.
· --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.
· --lock-tables, -l
For each dumped database, lock all tables to be dumped before dumping them. The tables are locked with
READ LOCAL to allow 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.
· --log-error=file_name
Log warnings and errors by appending them to the named file. The default is to do no logging. This option
was added in MySQL 5.1.18.
· --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.
mysql> STOP SLAVE SQL_THREAD;
mysql> SHOW SLAVE STATUS;
2. From the output of the SHOW SLAVE STATUS statement, the binary log coordinates of the master server
from which the new slave should start replicating are the values of the Relay_Master_Log_File and
Exec_Master_Log_Pos fields. Denote those values as file_name and file_pos.
3. Dump the slave server:
shell> mysqldump --master-data=2 --all-databases > dumpfile
4. Restart the slave:
mysql> START SLAVE;
5. On the new slave, load the dump file:
shell> mysql < dumpfile
6. On the new slave, set the replication coordinates to those of the master server obtained earlier:
mysql> CHANGE MASTER TO
-> MASTER_LOG_FILE = ´file_name´, MASTER_LOG_POS = file_pos;
The CHANGE MASTER TO statement might also need other parameters, such as MASTER_HOST to point the
slave to the correct master server host. Add any such parameters as necessary.
· --max-allowed-packet=length
Sets the maximum packet length to send to or recieve from server.
· --net-buffer-length=length
Sets the 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, -n
This option suppresses the CREATE DATABASE statements that are otherwise included in the output if the
--databases or --all-databases option is given.
· --no-create-info, -t
Do not write CREATE TABLE statements that re-create each dumped table.
· --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).
--disable-keys --extended-insert --lock-tables --quick --set-charset. It should give you a fast dump
operation and produce a dump file that can be reloaded into a MySQL server quickly.
The --opt option is enabled by default. Use --skip-opt to disable it. See the discussion at the beginning
of this section for information about selectively enabling or disabling a subset of the options affected
by --opt.
· --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 will make the dump
operation take considerably longer.
· --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 5.3.2.2, “End-User
Guidelines for Password Security”. You can use an option file to avoid giving the password on the command
line.
· --pipe, -W
On Windows, connect to the server via a named pipe. This option applies only if the server supports
named-pipe connections.
· --port=port_num, -P port_num
The TCP/IP port number to use for the connection.
· --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
allowable values, see Section 4.2.2, “Connecting to the MySQL Server”.
· --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.
· --print-defaults
Print the program argument list and exit. This must begiven as the first argument.
· --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.
Included stored routines (procedures and functions) for the dumped databases in the output. Use of 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 re-create the routines. However, these
statements do not include attributes such as the routine creation and modification timestamps. This means
that when the routines are reloaded, they will be created with the timestamps equal to the reload time.
If you require routines to be re-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.
This option was added in MySQL 5.1.2. Before that, stored routines are not dumped. Routine DEFINER values
are not dumped until MySQL 5.1.8. This means that before 5.1.8, when routines are reloaded, they will be
created with the definer set to the reloading user. If you require routines to be re-created with their
original definer, dump and load the contents of the mysql.proc table directly as described earlier.
· --set-charset
Add SET NAMES default_character_set to the output. This option is enabled by default. To suppress the SET
NAMES statement, use --skip-set-charset.
· --single-transaction
This option 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 BEGIN 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.
This option is not supported for MySQL Cluster tables; the results cannot be guaranteed to be consistent
due to the fact that the NDBCLUSTER storage engine supports only the READ_COMMITTED transaction isolation
level. You should always use NDB backup and restore instead.
To dump large tables, you should combine the --single-transaction option with --quick.
· --skip-comments
See the description for the --comments option.
· --skip-opt
See the description for the --opt option.
· --socket=path, -S path
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. You
must have the FILE privilege, and the server must have permission to write files in the directory that
you specify.
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.
As of MySQL 5.1.38, column values are converted to the character set specified by the
--default-character-set option. Prior to 5.1.38 or if no such option is present, values are dumped using
the binary character set. In effect, there is no character set conversion. If a table contains columns in
several character sets, the output data file will as well and you may not be able to reload the file
correctly.
· --tables
Override the --databases or -B option. mysqldump regards all name arguments following the option as table
names.
· --triggers
Include triggers for each dumped table in the output. This option is enabled by default; disable it with
--skip-triggers.
· --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. This option was added in MySQL 5.1.2.
· --user=user_name, -u user_name
The MySQL user name to use when connecting to the server.
· --verbose, -v
Verbose mode. Print more information about what the program does.
· --version, -V
Display version information and exit.
· --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:
┌──────────────────────┬──────────────────────────────────────────────────────────────────────────────────┐
│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> │
└──────────────────────┴──────────────────────────────────────────────────────────────────────────────────┘
Beginning with MySQL 5.1.12, the output from the mysql client when run using the --xml option also follows
the preceding rules. (See the section called “MYSQL OPTIONS”.)
Beginning with MySQL 5.1.18, 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>
You can also set the following variables by using --var_name=value syntax:
A common use of mysqldump is for making a backup of an entire database:
shell> mysqldump db_name > backup-file.sql
You can load the dump file back into the server like this:
shell> mysql db_name < backup-file.sql
Or like this:
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
It is possible to 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 --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 5.2.4,
“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 6.2, “Database Backup Methods”, and Section 6.3, “Example
Backup and Recovery Strategy”.
If you encounter problems backing up views, please read the section that covers restrictions on views which
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/.
NOTES
1. Bug#30123
http://bugs.mysql.com/bug.php?id=30123
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
Sun Microsystems, Inc. (http://www.mysql.com/).
MySQL 5.1 04/06/2010 MYSQLDUMP(1)
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