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FBMYSQLDUMPFR(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 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 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.
To get a list of the options your version of mysqldump supports, execute
mysqldump --help.
If you run mysqldump without the --quick or --opt option, 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 --opt option is enabled by
default, but can be disabled with --skip-opt.
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 --opt
or --extended-insert option. Use --skip-opt instead.
mysqldump supports the following options:
· --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 2.16, 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.
· --character-sets-dir=path
The directory where character sets are installed. See Section 9.1, 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 additional, use --skip-comments.
· --compact
Produce less verbose output. This option suppresses comments and enables
the --skip-add-drop-table, --no-set-names, --skip-disable-keys, and
--skip-add-locks 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 the section called 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.
· --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. The debug_options string is often
'd:t:o,file_name'. The default is 'd:t:o,/tmp/mysqldump.trace'.
· --default-character-set=charset_name
Use charset_name as the default character set. See Section 9.1, The
Character Set Used for Data and Sorting. If not specified, mysqldump
uses utf8.
· --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 for MyISAM tables only.
· --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=...,
--lines-terminated-by=...
These options are used with the -T option and have the same meaning as
the corresponding clauses for LOAD DATA INFILE. See Section 2.5, 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.
· --force, -f
Continue even if an SQL error occurs during a table dump.
· --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, and
BLOB. As of MySQL 5.0.13, BIT columns are affected as well.
· --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.
· --insert-ignore
Write INSERT statements with the IGNORE option.
· --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 starting the dump. 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. 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.
· --master-data[=value]
Write the binary log filename and position to the output. This option
requires the RELOAD 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 2, the CHANGE MASTER statement is written as an SQL
comment. This is the default action if value is omitted.
The --master-data option turns on --lock-all-tables, unless
--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 description for --single-transaction. In all cases, any action
on logs happens at the exact moment of the dump. This option
automatically turns off --lock-tables.
· --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 row information for the table. 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. To disable the options that it
enables, use --skip-opt. To disable only certain of the options enabled
by --opt, use their --skip forms; for example, --skip-add-drop-table or
--skip-quick.
· --order-by-primary
Sorts each table's rows by its primary key, or 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 7.6, Keeping Your Password Secure.
· --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.
· --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.
· --result-file=file, -r file
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.
· --routines, -R
Dump stored routines (functions and procedures) from the dumped
databases. 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 5.0.13. 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 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 issues a BEGIN SQL statement before dumping data from the
server. It is useful only with transactional tables such as InnoDB and
BDB, 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.
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 big tables, you should combine this option with --quick.
· --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.
· --skip-comments
See the description for the --comments option.
· --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 7.7.3, 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--xxx
options.
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. All name arguments following the
option are regarded as table names.
· --triggers
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.
· --tz-utc
Add 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, 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. This option was added in MySQL 5.0.15.
· --user=user_name, -u user_name
The MySQL username 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. Note that 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.
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.
It is also possible to set variables by using --set-variable=var_name=value
or -O var_name=value syntax. This syntax is deprecated.
The most common use of mysqldump is probably for making a backup of an
entire database:
shell> mysqldump --opt 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 just needs to acquire 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 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 10.3, 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 simultaneous use of --master-data and --single-transaction provides a
convenient way to make an online backup suitable for point-in-time recovery
if tables are stored in the InnoDB storage engine.
For more information on making backups, see Section 8.1, Database Backups,
and Section 8.2, Example Backup and Recovery Strategy.
SEE ALSO
msql2mysql(1), myisam_ftdump(1), myisamchk(1), myisamlog(1), myisampack(1),
mysql(1), mysql.server(1), mysql_config(1), mysql_fix_privilege_tables(1),
mysql_upgrade(1), mysql_zap(1), mysqlaccess(1), mysqladmin(1),
mysqlbinlog(1), mysqlcheck(1), mysqld(1), mysqld_multi(1), mysqld_safe(1),
mysqlhotcopy(1), mysqlimport(1), mysqlmanager(1), mysqlshow(1), perror(1),
replace(1), safe_mysqld(1)
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/). This software comes with no warranty.
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