Linux mysqldump command

Updated: 11/06/2021 by Computer Hope
mysqldump command

On Unix-like operating systems running MySQL, the mysqldump command "dumps" a MySQL database, or a collection of databases, for backup or transferral to another SQL server.


The mysqldump client is a utility that performs logical backups, producing a set of SQL statements that can reproduce the original schema objects, table data, or both. It dumps one or more MySQL database 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 same privileges needed to create each of the dumped objects by issuing CREATE statements manually.

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.

Performance and scalability considerations

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, etc.

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:

  • If your tables are primarily InnoDB tables, or if you have a mix of InnoDB and MyISAM tables, a better tool may be the mysqlbackup command of the MySQL Enterprise Backup product (which is not free). It provides the best performance for InnoDB backups, and can also back up tables from MyISAM and other storage engines; and it provides many convenient options to accommodate different backup scenarios.
  • If your tables are primarily MyISAM tables, consider using the mysqlhotcopy instead, for better performance than mysqldump of backup and restore operations.

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 cause problems 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.

Invoking mysqldump

There are three general ways to use mysqldump. It can dump a set of one or more tables, a set of one or more complete databases, or an entire MySQL server. These three uses, respectively, are shown here:

mysqldump [options] db_name [tbl_name ...]
mysqldump [options] --databases db_name ...
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 [options] [db_name [tbl_name ...]]


mysqldump supports the following options, which can be specified on the command line or in the [mysqldump] and [client] groups of an option file.

Connection options

On a computer having multiple network interfaces, this option can select which interface is employed when connecting to the MySQL server. This option is supported beginning with MySQL 5.6.1.
Compress all information sent between the client and the server if both support compression.
The client-side authentication plugin to use.
-h host_name
Dump data from the MySQL server on the given host. The default host is localhost.
Read options from the named login path in the .mylogin.cnf login file. A "login path" is an option group that permits only a limited set of options: host, user, and password. Think of a login path as a set of values that indicate the server host and the credentials for authenticating with the server. To create the login file, use the mysql_config_editor utility. This option was added in MySQL 5.6.6.
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 since anyone who can view your processes (for instance, with the ps command) you can see your password as plaintext.
On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections.
The directory where to look for plugins. It may be necessary to specify this option if the --default-auth option is used to specify an authentication plugin, but mysqldump does not find it.
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.
Do not send passwords to the server in old (pre-4.1) format. This prevents connections except for servers that use the newer password format. This option is enabled by default; use --skip-secure-auth to disable it. This option was added in MySQL 5.6.17.

Note: Passwords that use the pre-4.1 hashing method are less secure than passwords that use the native password hashing method and should be avoided. Pre-4.1 passwords are deprecated and support for them is removed in later MySQL releases.
--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.
Options that begin with --ssl specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates.
--user=user_name, -u user_name
The MySQL username to use when connecting to the server.

You can also set the following variables using --var_name=value syntax:

The maximum size of the buffer for client/server communication. The default is 24 MB, the maximum is 1 GB.
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 length. If you increase this variable, ensure the net_buffer_length variable in the MySQL server is at least this large.

DDL options

Usage scenarios for mysqldump include setting up an entire new MySQL instance (including database tables), and replacing data inside an existing instance with existing databases and tables.

The following options let you specify which things to tear down and set up when restoring a dump, by encoding various DDL statements in the dump file.

Add a DROP DATABASE statement before each CREATE DATABASE statement. This option is used with the --all-databases or --databases option because no CREATE DATABASE statements are written unless one of those options is specified.
Add a DROP TABLE statement before each CREATE TABLE statement.
Add a DROP TRIGGER statement before each CREATE TRIGGER statement.
Adds to a table dump all SQL statements needed to create any tablespaces used by an NDB table. This information is not otherwise included in the output from mysqldump. This option is currently relevant only to MySQL Cluster tables.
This option suppresses the CREATE DATABASE statements that are otherwise included in the output if the --databases or --all-databases option is given.
Do not write CREATE TABLE statements that re-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.
This option suppresses all CREATE LOGFILE GROUP and CREATE TABLESPACE statements in the output of mysqldump.
Write REPLACE statements rather than INSERT statements.

Debug options

The following options print debugging information, encode debugging information in the dump file, or let the dump operation proceed regardless of potential problems.

Permit creation of column names that are keywords. This works by prefixing each column name with the table name.
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.
--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.
Print some debugging information when the program exits.
Print debugging information and memory and CPU usage statistics when the program exits.
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 is 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.
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 became invalid because the definition refers to a table that was 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.
Log warnings and errors by appending them to the named file. The default is to do no logging.
See the description for the --comments option.
Verbose mode. Print more information about what the program does.

Help options

The following options display information about the mysqldump command itself.

Display a help message and exit.
Display version information and exit.

The following options change how the mysqldump command represents character data with national language settings.

The directory where character sets are installed.
Use charset_name as the default character set. If no character set is specified, mysqldump uses utf8, and earlier versions use latin1.
--no-set-names, -N
Turns off the --set-charset setting, the same as specifying --skip-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.

Replication options

The mysqldump command is frequently used to create an empty instance, or an instance including data, on a slave server in a replication configuration. The following options apply to dumping and restoring data on replication master and slave servers.

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.
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.
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 set up another server as a slave with 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. Also, specifying 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.
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 hostname and TCP/IP port number of the slave's master.
Use this option to dump a master replication server to produce a dump file that can 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, where 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, using the --dump-slave option, which overrides --master-data and causes it to be ignored if both options are used.

Before MySQL 5.6.4, this option was required for dumping the replication log tables.
This option enables control over GTID (global transaction ID) information written to the dump file, by indicating whether to add a SET @@global.gtid_purged statement to the output.

The following table shows the permitted option values. The default value is AUTO.

value meaning
OFF Add no SET statement to the output.
ON Add a SET statement to the output. An error occurs if GTIDs are not enabled on the server.
AUTO Add a SET statement to the output if GTIDs are enabled on the server.

This option was added in MySQL 5.6.9.

Format options

The following options specify how to represent the entire dump file or certain kinds of data in the dump file. They also control whether certain optional information is written to the dump file.

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.
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.

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.
Use complete INSERT statements that include column names.
Include all MySQL-specific table options in the CREATE TABLE statements.
These options are used with the --tab option and have the same meaning as the corresponding FIELDS clauses for LOAD DATA INFILE.
Dump binary columns using hexadecimal notation (for example, 'abc' becomes 0x616263). The affected data types are BINARY, VARBINARY, the BLOB types, and BIT.
This option is used with the --tab option and has the same meaning as the corresponding LINES clause for LOAD DATA INFILE.
Quote identifiers (such as database, table, and column names) within "`" (backtick) characters. If the ANSI_QUOTES SQL mode is enabled, identifiers are quoted in """ (double-quote) 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_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 previous contents overwritten, even if an error occurs while generating the dump.
--tab=path-T path
Produce tab-separated text-format data files. For each dumped table, mysqldump creates a tbl_name.sql file containing the CREATE TABLE statement that creates the table, and the server writes a tbl_name.txt file contains its data. The option value is the directory where files are written.

Note: This option should be used only when mysqldump is run on the same machine as the mysqld server. You must have the FILE privilege, and the server must have permission to write files in the directory that you specify. By default, the .txt data files are formatted using tab characters between column values and a newline at the end of each line. The format can be specified explicitly using the --fields-xxx and --lines-terminated-by options.

Column values are converted to the character set specified by the --default-character-set option.
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.
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.
value xml representation
(unknown value)
<field name="column_name" xsi:nil="true" />
(empty string)
<field name="column_name"></field>
(string value)
<field name="column_name">NULL</field>

The output from the mysql client when run using the --xml option also follows the preceding rules.

Filtering options

The following options control which kinds of schema objects are written to the dump file: by category, such as triggers or events; by name, for example, choosing which databases and tables to dump; or even filtering rows from the table data using a WHERE clause.

Dump all tables in all databases. This is the same as using the --databases option and naming all databases on the command line.

Before MySQL 5.6.4, the slave_master_info and slave_relay_log_info tables (see section 16.2.2, "Replication Relay and Status Logs") were not included by this option.
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.
Include Event Scheduler events for the dumped databases in the output.
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 ignore views.
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).
Include stored routines (procedures and functions) for the dumped databases in the output. Use of this option requires the SELECT privilege for the mysql.proc table. The output generated 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 are 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 with the appropriate privileges for the mysql database.

Before MySQL 5.6.5, this option had no effect when used together with the --xml option.
Override the --databases or -B option. mysqldump regards all name arguments following the option as table names.
Include triggers for each dumped table in the output. This option is enabled by default; disable it with --skip-triggers.
--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:


Performance options

The following options are the most relevant for the performance particularly of the restore operations. For large data sets, restore operation (processing the INSERT statements in the dump file) is the most time-consuming part. When it is urgent to restore data quickly, plan and test the performance of this stage in advance. For restore times measured in hours, you might prefer an alternative backup and restore solution, such as MySQL Enterprise Backup for InnoDB-only and mixed-use databases, or mysqlhotcopy for MyISAM-only databases.

Performance is also affected by the transactional options, primarily for the dump operation.

For those non-transactional tables that support the INSERT DELAYED syntax, use that statement rather than regular INSERT statements.

As of MySQL 5.6.6, DELAYED inserts are deprecated, so this option is removed in later releases.
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.
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.
Write INSERT IGNORE statements rather than INSERT statements.
This option, enabled by default, is shorthand for the combination of --add-drop-table --add-locks --create-options --disable-keys --extended-insert --lock-tables --quick --set-charset. It gives a fast dump operation and produces a dump file that can be reloaded into a MySQL server quickly.

Because the --opt option is enabled by default, you only specify its converse, the --skip-opt to turn off several default settings. See the discussion of mysqldump option groups for information about selectively enabling or disabling a subset of the options affected by --opt.
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.
See the description for the --opt option.

Transactional options

The following options trade off the performance of the dump operation, against the reliability and consistency of the exported data.

Surround each table dump with LOCK TABLES and UNLOCK TABLES statements. This results in faster inserts when the dump file is reloaded.
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 --single-transaction: 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 the same moment, use --flush-logs together with --lock-all-tables, --master-data, or --single-transaction.
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.
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.
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 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.
Enclose the INSERT statements for each dumped table within SET autocommit = 0 and COMMIT statements.
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 makes the dump operation take considerably longer.
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, realize 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.

To dump large tables, combine the --single-transaction option with the --quick option.

Option groups

  • The --opt option turns on several settings that work together to perform a fast dump operation. All these settings are on by default, because --opt is on by default. Thus you rarely if ever specify --opt. Instead, you can turn these settings off as a group by specifying --skip-opt, then optionally re-enable certain settings by specifying the associated options later on the command line.
  • The --compact option turns off several settings that control whether optional statements and comments appear in the output. Again, you can follow this option with other options that re-enable certain settings, or turn all the settings on using the --skip-compact form.

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.

Usage notes

  • To select the effect of --opt, except for some features, use the --skip option for each feature. To disable extended inserts and memory buffering, use --opt --skip-extended-insert--skip-quick. (Actually, --skip-extended-insert --skip-quick is sufficient because --opt is on by default.)
  • To reverse --opt for all features, except index disabling and table locking, use --skip-opt --disable-keys --lock-tables.


  • mysqldump does not dump the INFORMATION_SCHEMA database by default. To dump INFORMATION_SCHEMA, name it explicitly on the command line and also use the --skip-lock-tables option.
  • mysqldump never dumps the performance_schema database.
  • mysqldump also does not dump the MySQL Cluster ndbinfo information database.
  • Before MySQL 5.6.6, mysqldump does not dump the general_log or slow_query_log tables for dumps of the mysql database. As of 5.6.6, 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 db_name > backup-file.sql

Back up the entire database db_name to the file backup-file.sql.

mysql db_name < backup-file.sql

Load the backup file backup-file.sql into the database db_name.

mysql -e "source /path-to-backup/backup-file.sql" db_name

This is another way to do the same as the previous example (load the backup file into the database).

mysqldump --opt db_name | mysql --host=remote_host -C db_name

Populate a remote mysql server's database db_name with local database db_name.

mysqldump --databases db_name1 [db_name2 ...] > my_databases.sql

The command above dumps multiple databases (db_name1, db_name2...) to the single backup file my_databases.sql.

mysqldump --all-databases > all_databases.sql

Dumps all databases to the backup file all_databases.sql.

myisamchk — Check, repair, optimize, or fetch information about a MySQL database.
mysql — An open-source relational database management system.