MYSQLDUMP(1) MySQL Database System MYSQLDUMP(1)NAMEmysqldump - a database backup program
SYNOPSISmysqldump [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 [tables]
shell> mysqldump [options] --databases db_name1 [db_name2 db_name3...]
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. If you name
that database explicitly on the command line, mysqldump silently
ignores it.
To get a list of the options your version of mysqldump supports,
execute mysqldump--help.
Some mysqldump options are shorthand for groups of other options.
--opt and --compact fall into this category. For example, use of --opt
is the same as specifying --add-drop-table --add-locks --create-options
--disable-keys --extended-insert --lock-tables --quick --set-charset.
Note that all of the options that --opt stands for also are on by
default because --opt is on by default.
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. For example, to disable extended
inserts and memory buffering, use --opt --skip-extended-insert
--skip-quick. (As of MySQL 6.0, --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 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 in MySQL 6.0; 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, you should not use the --opt or
--extended-insert option. Use --skip-opt instead.
mysqldump supports the options in the following list. It also reads
option files and supports the options for processing them described at
Section 4.2.3.2.1, “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.
· --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 7.2.24, “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.
· --allow-keywords
Allow creation of column names that are keywords. This works by
prefixing each column name with the table name.
· --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. This option was added in
MySQL 6.0.4.
· --character-sets-dir=path
The directory where character sets are installed. See Section 9.2,
“The Character Set Used for Data and Sorting”.
· --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 less verbose output. This option enables the
--skip-add-drop-table, --skip-add-locks, --skip-comments,
--skip-disable-keys, and --skip-set-charset options.
· --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 5.1.7, “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.
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
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.
· --debug-info
Print debugging information and memory and CPU usage statistics when
the program exits.
· --default-character-set=charset_name
Use charset_name as the default character set. See Section 9.2, “The
Character Set Used for Data and Sorting”. If no character set is
specified, mysqldump uses utf8, and earlier versions use latin1.
This option has no effect for output data files produced by using
the --tab option. See the description for that option.
· --delayed-insert
Write INSERT DELAYED statements rather than INSERT statements.
· --delete-master-logs
On a master replication server, delete the binary logs after
performing the dump operation. This option automatically enables
--master-data.
· --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 non-unique indexes of MyISAM tables.
· --dump-date
mysqldump produces a -- Dump completed on DATE comment at the end of
the dump if the --comments option is given. However, the date causes
dump files for identical data take at different times to appear to
be different. --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 6.0.4.
· --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 (rather than the
coordinates of the dumped server, as is done by the --master-data
option). These are the master server coordinates from which the
slave should start replicating. This option was added in MySQL
6.0.4.
The option value is handled the same way as for --master-data and
has the same effect as --master-data in terms of enabling or
disabling other options and in how locking is handled.
In conjunction with --dump-slave, the --apply-slave-statements and
--include-master-host-port options can also be used.
· --events, -E
Dump events from the dumped databases.
· --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 -T option and have the same meaning
as the corresponding clauses for LOAD DATA INFILE. See
Section 12.2.6, “LOAD DATA INFILE Syntax”.
· --first-slave, -x
Deprecated. Now renamed to --lock-all-tables.
· --flush-logs, -F
Flush the MySQL server log files before starting the dump. This
option requires the RELOAD privilege. Note that if you use this
option in combination with the --all-databases (or -A) 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
Emit a FLUSH PRIVILEGES statement 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.
· --force, -f
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.
· --host=host_name, -h host_name
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,
BLOB, and BIT.
· --include-master-host-port
For the CHANGE MASTER TO statement in a slave dump produced with the
--dump-slave option, add MASTER_PORT and MASTER_PORT options for the
host name and TCP/IP port number of the slave's master. This option
was added in MySQL 6.0.4.
· --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 statements with the IGNORE option.
· --lines-terminated-by=...
This option is used with the -T option and has the same meaning as
the corresponding 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
Lock all tables 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 and BDB, --single-transaction is
a much better option, because it does not need to lock the tables at
all.
Please note that when dumping multiple databases, --lock-tables
locks tables for each database separately. Therefore, 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
Append warnings and errors to the named file.
· --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.
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 takes effect when the dump file is reloaded. If the option
value is not 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. To do this, use the --dump-slave option instead.
· --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 very useful if you want to dump only the CREATE
TABLE statement for the table.
· --opt
This option is shorthand; it is the same as specifying
--add-drop-table --add-locks --create-options --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 certain of the
options affected by --opt.
· --order-by-primary
Sorts each table's rows 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
itself 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, you are prompted for
one.
Specifying a password on the command line should be considered
insecure. See Section 5.5.6.2, “End-User Guidelines for Password
Security”.
· --pipe, -W
On Windows, connect to the server via a named pipe. This option
applies only for connections to a local server, and 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.
· --quote-names, -Q
Quote database, table, and column names within “`” characters. If
the ANSI_QUOTES SQL mode is enabled, names 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.
· --replace
Write REPLACE statements rather than INSERT statements.
· --result-file=file_name, -r file_name
Direct output to a given file. This option should be used on Windows
to prevent newline “\n” characters from being converted to “\r\n”
carriage return/newline sequences. The result file is created and
its contents overwritten, even if an error occurs while generating
the dump. The previous contents are lost.
· --routines, -R
Dump stored routines (procedures and functions) from the dumped
databases. 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.
· --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 issues a BEGIN SQL statement before dumping data from
the server. 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 and
Falcon 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 position), no other
connection should use the following statements: ALTER 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 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, you should combine this 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
For connections to localhost, the Unix socket file to use, or, on
Windows, the name of the named pipe to use.
· --ssl*
Options that begin with --ssl specify whether to connect to the
server via SSL and indicate where to find SSL keys and certificates.
See Section 5.5.7.3, “SSL Command Options”.
· --tab=path, -T path
Produce tab-separated data files. For each dumped table, mysqldump
creates a tbl_name.sql file that contains the CREATE TABLE statement
that creates the table, and a tbl_name.txt file that contains its
data. The option value is the directory in which to write the files.
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 dumped using the binary character set and the
--default-character-set option is ignored. 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.
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.
· --tables
Override the --databases or -B option. mysqldump regards all name
arguments following the option as table names.
· --triggers
Dump triggers for each dumped table. 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. --tz-utc also
protects against changes due to daylight saving time. --tz-utc is
enabled by default. To disable it, use --skip-tz-utc.
· --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:
--where="user='jimf'"
-w"userid>1"
-w"userid<1"
· --xml, -X
Write dump output as well-formed XML.
NULL, 'NULL', and Empty Values: For some 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" │
│ │ /> │
├──────────────────────┼─────────────────────────────────────────────────────┤
│´' (empty string) │ <field │
│ │ name="column_name"></field> │
├──────────────────────┼─────────────────────────────────────────────────────┤
│´NULL' (string value) │ <field │
│ │ name="column_name">NULL</field> │
└──────────────────────┴─────────────────────────────────────────────────────┘
The output from the mysql client when run using the --xml option
also follows these 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="27329
3" Max_data_length="18858823439613951" Index_length="43008" Data_free="0" Auto_increment="4080" Create_time="2007-03-31 01:47:01" Updat
e_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:
· max_allowed_packet
The maximum size of the buffer for client/server communication. The
maximum is 1GB.
· net_buffer_length
The initial size of the buffer for client/server communication. When
creating multiple-row-insert statements (as with option
--extended-insert or --opt), mysqldump creates rows up to
net_buffer_length length. If you increase this variable, you should
also ensure that the net_buffer_length variable in the MySQL server
is at least this large.
The most common use of mysqldump is probably for making a backup of an
entire database:
shell> mysqldump db_name > backup-file.sql
You can read 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 point-in-time recovery if tables are stored using
the InnoDB storage engine.
For more information on making backups, see Section 6.1, “Database
Backups”, and Section 6.2, “Example Backup and Recovery Strategy”.
If you encounter problems backing up views, please read the section
that covers restrictions on views which describes a workaround for
backing up views when this fails due to insufficient privileges. See
Section D.5, “Restrictions on Views”.
COPYRIGHT
Copyright 2007-2008 MySQL AB, 2009 Sun Microsystems, Inc.
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
MySQL AB (http://www.mysql.com/).
MySQL 6.0 04/30/2009 MYSQLDUMP(1)
