YoLinux.com: mysqldump manpage

MYSQLDUMP(1) MySQL Database System MYSQLDUMP(1)

NAME
mysqldump - a database backup program

SYNOPSIS
mysqldump [options] [db_name [tbl_name ...]]

DESCRIPTION
o Performance and Scalability Considerations

o Invocation Syntax

o Option Syntax - Alphabetical Summary

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.

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.

If you are performing a backup on the server and your tables all are
MyISAM tables, you can also use mysqlhotcopy for this purpose.

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 25.2, "MySQL Enterprise Backup Overview".

o If your tables are primarily MyISAM tables, consider using the
mysqlhotcopy instead, for better performance than mysqldump of
backup and restore operations. See mysqlhotcopy(1).

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.

mysqldump does not dump the INFORMATION_SCHEMA or performance_schema
database by default. To dump either of these, name it explicitly on the
command line and also use the --skip-lock-tables option. You can also
name them with the --databases option. Before MySQL 5.5 mysqldump
silently ignores INFORMATION_SCHEMA even if you name it explicitly on
the command line.

mysqldump does not dump the performance_schema database.

Before MySQL 5.5.25, mysqldump does not dump the general_log or
slow_query_log tables for dumps of the mysql database. As of 5.5.25,
the dump includes statements to recreate those tables so that they are
not missing after reloading the dump file. Log table contents are not
dumped.

mysqldump also does not dump the NDB Cluster ndbinfo information
database.

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:

o 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.

o 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:

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.

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.

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.

For additional information about mysqldump, see Section 7.4, "Using
mysqldump for Backups". 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".

o --help, -?

Display a help message and exit.

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.

Note
This option is supported only by mysqldump as supplied with NDB
Cluster. It is not available when using MySQL Server 5.5.

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 --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 --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 NDB Cluster tables.

o --allow-keywords

Permit creation of column names that are keywords. This works by
prefixing each column name with the table name.

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. This option was added in
MySQL 5.5.3.

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.

This option is supported only in the version of mysqldump that is
supplied with NDB Cluster. It is not available in standard MySQL
Server 5.5 releases.

o --character-sets-dir=dir_name

The directory where character sets are installed. See
Section 10.14, "Character Set Configuration".

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 --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 --compress, -C

Compress all information sent between the client and the server if
both support compression.

o --create-options

Include all MySQL-specific table options in the CREATE TABLE
statements.

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 --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 --default-auth=plugin

A hint about the client-side authentication plugin to use. See
Section 6.3.6, "Pluggable Authentication".

This option was added in MySQL 5.5.9.

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 --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. Before MySQL 5.5.8,
file_name must be the full path name to the file. As of MySQL
5.5.8, the name is interpreted relative to the current directory if
given as a relative 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. Before MySQL 5.5.8,
file_name must be the full path name to the file. As of MySQL
5.5.8, the name is interpreted relative to the current directory if
given as a relative path name.

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 --delayed-insert

Write INSERT DELAYED statements rather than INSERT statements.

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 --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. It
has no effect for other tables.

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 --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. These are the
master server coordinates from which the slave should start
replicating.

--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.

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.

This option was added in MySQL 5.5.3.

o --events, -E

Include Event Scheduler events for the dumped databases in the
output. This option requires the EVENT privileges for those
databases.

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 --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 --first-slave

Deprecated. Use --lock-all-tables instead. --first-slave was
removed in MySQL 5.5.3.

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 (as of MySQL 5.5.21)
--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.

o --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.

o --enable-cleartext-plugin

Enable the mysql_clear_password cleartext authentication plugin.
(See Section 6.5.1.3, "Client-Side Cleartext Pluggable
Authentication".)

This option was added in MySQL 5.5.47.

o --host=host_name, -h host_name

Dump data from the MySQL server on the given host. The default host
is localhost.

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 --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.
This option was added in MySQL 5.5.3.

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 --insert-ignore

Write INSERT IGNORE statements rather than INSERT statements.

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 --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 --log-error=file_name

Log warnings and errors by appending them to the named file. The
default is to do no logging.

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. In MySQL 5.5.3 and higher, you can create such a
dump using the --dump-slave option, which overrides --master-data
and causes it to be ignored if both options are used.

Before MySQL 5.5.3, use the following procedure on the existing
slave:

1. Stop the slave's SQL thread and get its current status:

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

Using --master-data=2 works only if binary logging has been
enabled on the slave. Otherwise, mysqldump fails with the error
Binlogging on server not active. In this case you must handle
any locking issues in another manner, using one or more of
--add-locks, --lock-tables, --lock-all-tables, or
--single-transaction, as required by your application and
environment.

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.

o --no-autocommit

Enclose the INSERT statements for each dumped table within SET
autocommit = 0 and COMMIT statements.

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-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 --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.

o --no-set-names, -N

This has the same effect as --skip-set-charset.

o --no-tablespaces, -y

This option suppresses all CREATE LOGFILE GROUP and CREATE
TABLESPACE statements in the output of mysqldump.

o --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 a subset of the
options affected by --opt.

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 will make the
dump operation take considerably longer.

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 6.3.6,
"Pluggable Authentication".

This option was added in MySQL 5.5.9.

o --port=port_num, -P port_num

The TCP/IP port number to use for the connection.

o --print-defaults

Print the program name and all options that it gets from option
files.

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 --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 --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 --replace

Write REPLACE statements rather than INSERT statements.

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 --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.

Prior to MySQL 5.5.21, this option had no effect when used together
with the --xml option. (Bug #11760384, Bug #52792)

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.

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.

This option is not supported for NDB 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, combine the --single-transaction option with
the --quick option.

o --skip-comments

See the description for the --comments option.

o --skip-opt

See the description for the --opt option.

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 --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 --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.

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 --user=user_name, -u user_name

The MySQL user name to use when connecting to the server.

o --verbose, -v

Verbose mode. Print more information about what the program does.

o --version, -V

Display version information and exit.

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"

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.

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>

Prior to MySQL 5.5.21, this option prevented the --routines option
from working correctly--that is, no stored routines, triggers, or
events could be dumped in XML format. (Bug #11760384, Bug #52792)

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.

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 --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".

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 C.5, "Restrictions on Views".

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 5.5 08/28/2018 MYSQLDUMP(1)

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