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 for transferring the data to another SQL server (not necessarily a MySQL server). The dump contains SQL statements to create the table or populate it, or both.
If you are doing a backup on the server, and your tables all
MyISAM tables, consider using the
mysqlhotcopy instead because it can
accomplish faster backups and faster restores. See
Section 8.13, “mysqlhotcopy — A Database Backup Program”.
There are three general ways to invoke mysqldump:
If you do not name any tables following
db_name or if you use the
--all-databases option, entire databases are
To get a list of the options your version of mysqldump supports, execute mysqldump --help.
If you run mysqldump without the
mysqldump loads the whole result set into
memory before dumping the result. This can be a problem if you
are dumping a big database. The
is enabled by default, but can be disabled with
If you are using a recent copy of the
mysqldump program to generate a dump to be
reloaded into a very old MySQL server, you should not use the
mysqldump supports the following options:
Display a help message and exit.
DROP DATABASE statement before
CREATE DATABASE statement.
DROP TABLE statement before each
CREATE TABLE statement.
Surround each table dump with
statements. This results in faster inserts when the dump
file is reloaded. See Section 7.2.16, “Speed of
Dump all tables in all databases. This is the same as
--databases option and naming
all the databases on the command line.
Allow creation of column names that are keywords. This works by prefixing each column name with the table name.
The directory where character sets are installed. See Section 5.11.1, “The Character Set Used for Data and Sorting”.
Write additional information in the dump file such as
program version, server version, and host. . This option
is enabled by default. To suppress additional, use
Produce less verbose output. This option suppresses
comments and enables the
Produce output that is more compatible with other database
systems or with older MySQL servers. The value of
name can be
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 5.2.5, “The Server SQL Mode”.
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.
INSERT statements that
include column names.
Compress all information sent between the client and the server if both support compression.
Include all MySQL-specific table options in the
CREATE TABLE statements.
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.
Write a debugging log. The
debug_options string is often
The default is
charset_name as the default
character set. See Section 5.11.1, “The Character Set Used for Data and Sorting”. If
not specified, mysqldump uses
INSERT DELAYED statements rather
On a master replication server, delete the binary logs
after performing the dump operation. This option
For each table, surround the
/*!40000 ALTER TABLE
tbl_name DISABLE KEYS
/*!40000 ALTER TABLE
statements. This makes loading the dump file
faster because the indexes are created after all rows are
inserted. This option is effective for
tbl_name ENABLE KEYS
MyISAM tables only.
INSERT syntax that
VALUES lists. This
results in a smaller dump file and speeds up inserts when
the file is reloaded.
These options are used with the
and have the same meaning as the corresponding clauses for
LOAD DATA INFILE. See
Section 13.2.5, “
LOAD DATA INFILE Syntax”.
Deprecated. Now renamed to
Flush the MySQL server log files before starting the dump.
This option requires the
privilege. Note that if you use this option in combination
-A) option, the logs are flushed
for each database dumped. The
exception is when using
--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
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 defintion refers to a table that has been dropped.
mysqldump exits with an error message.
mysqldump prints the error message, but
it also writes a SQL comment containing the view
definition to the dump output and continues executing.
Dump data from the MySQL server on the given host. The
default host is
Dump binary columns using hexadecimal notation (for
0x616263). The affected data types are
BLOB. As of MySQL 5.0.13,
BIT columns are affected as well.
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.
INSERT statements with the
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
Lock all tables before starting the dump. The tables are
READ LOCAL to allow
concurrent inserts in the case of
MyISAM tables. For transactional tables
--single-transaction is a much better
option, because it does not need to lock the tables at
Please note that when dumping multiple databases,
--lock-tables locks tables for each
database separately. So, 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.
Write the binary log filename and position to the output.
This option requires the
privilege and the binary log must be enabled. If the
option value is equal to 1, the position and filename are
written to the dump output in the form of a
CHANGE MASTER statement that makes a
slave server start from the correct position in the
master's binary logs if you use this SQL dump of the
master to set up a slave. If the option value is equal to
CHANGE MASTER statement is
written as an SQL comment. This is the default action if
value is omitted.
--master-data option turns on
--single-transaction also is specified
(in which case, a global read lock is only acquired a
short time at the beginning of the dump. See also the
all cases, any action on logs happens at the exact moment
of the dump. This option automatically turns off
INSERT statements for each
dumped table within
This option suppresses the
DATABASE statements that are otherwise included
in the output if the
--all-databases option is given.
Do not write
CREATE TABLE statements
that re-create each dumped table.
Do not write any row information for the table. This is
very useful if you want to dump only the
TABLE statement for the table.
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.
--opt option is enabled by
default. To disable the options that it enables, use
--skip-opt. To disable only
certain of the options enabled by
--skip forms; for example,
--skip-quick. Alternatively, use
--skip-opt to disable the options enabled
--opt, followed by options to enable
the features that you want. Options are processed in
order, so the options to enable features must follow
--skip-opt. For example,
--skip-opt --extended-insert enables
extended inserts, but
--skip-opt does not.
Sorts each table's rows by its primary key, or its first
unique index, if such an index exists. This is useful when
MyISAM table to be loaded
InnoDB table, but will make the
dump itself take considerably longer.
The password to use when connecting to the server. If you
use the short option form (
cannot have a space between the
option and the password. If you omit the
password value following the
on the command line, you are prompted for one.
Specifying a password on the command line should be considered insecure. See Section 5.9.6, “Keeping Your Password Secure”.
The TCP/IP port number to use for the connection.
The connection protocol to use.
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 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
this option should be given after any option such as
--compatible that may enable
Direct output to a given file. This option should be used
on Windows to prevent newline
\n’ characters from being
converted to ‘
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
Dump stored routines (functions and procedures) from the
dumped databases. The output generated by using
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
directly, using a MySQL account that has appropriate
privileges for the
This option was added in MySQL 5.0.13. Before that, stored
routines are not dumped. Routine
DEFINER values are not dumped until
MySQL 5.0.20. This means that before 5.0.20, 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
directly as described earlier.
to the output. This option is enabled by default. To
SET NAMES statement, use
This option issues a
statement before dumping data from the server. It is
useful only with transactional tables such as
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
tables dumped while using this option may still change
--single-transaction option and the
--lock-tables option are mutually
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
transaction isolation level. You should always use
NDB backup and restore instead.
To dump big tables, you should combine this option with
See the description for the
For connections to
localhost, the Unix
socket file to use, or, on Windows, the name of the named
pipe to use.
See the description for the
Options that begin with
whether to connect to the server via SSL and indicate
where to find SSL keys and certificates. See
Section 22.214.171.124, “SSL Command Options”.
Produce tab-separated data files. For each dumped table,
mysqldump creates a
file that contains the
statement that creates the table, and a
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
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.
-B option. All name arguments following
the option are regarded as table names.
Dump triggers for each dumped table. This option is
enabled by default; disable it with
--skip-triggers. This option was added in
MySQL 5.0.11. Before that, triggers are not dumped.
SET TIME_ZONE='+00:00' to the dump
file so that
TIMESTAMP columns can be
dumped and reloaded between servers in different time
zones. Without this option,
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
option was added in MySQL 5.0.15.
The MySQL username to use when connecting to the server.
Verbose mode. Print more information about what the program does.
Display version information and exit.
Dump only rows selected by the given
WHERE condition. Note that quotes
around the condition are mandatory if it contains spaces
or other characters that are special to your command
--where="user='jimf'" -w"userid>1" -w"userid<1"
Write dump output as well-formed XML.
You can also set the following variables by using
The maximum size of the buffer for client/server communication. The maximum is 1GB.
The initial size of the buffer for client/server
communication. When creating multiple-row-insert
statements (as with option
creates rows up to
length. If you increase this variable, you should also
ensure that the
variable in the MySQL server is at least this large.
It is also possible to set variables by using
syntax. This syntax is deprecated.
The most common use of mysqldump is probably for making a backup of an entire database:
You can read the dump file back into the server like this:
Or like this:
mysql -e "source
mysqldump is also very useful for populating databases by copying data from one MySQL server to another:
db_name| mysql --host=
It is possible to dump several databases with one command:
db_name2...] > my_databases.sql
To dump all databases, use the
mysqldump --all-databases > all_databases.sql
mysqldump provides a way of making an
mysqldump --all-databases --single-transaction > all_databases.sql
This backup just needs to acquire a global read lock on all
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 and only if one long updating statement is
running when the
FLUSH statement is issued,
the MySQL server may get stalled until that long statement
finishes, and then the dump becomes lock-free. 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 5.12.3, “The Binary Log”) or at least know the binary log coordinates to which the dump corresponds:
mysqldump --all-databases --master-data=2 > all_databases.sql
mysqldump --all-databases --flush-logs --master-data=2
The simultaneous use of
--single-transaction provides a convenient
way to make an online backup suitable for point-in-time
recovery if tables are stored in the
For more information on making backups, see Section 5.10.1, “Database Backups”, and Section 5.10.2, “Example Backup and Recovery Strategy”.