Mysqldump is a command-line utility in Linux that is used to back up MySQL databases. It is a part of the MySQL database management system and can be used to create backups of individual databases or the entire MySQL server. The mysqldump command is an essential tool for database administrators who need to create backups of their MySQL databases to ensure data integrity.
Overview
The mysqldump command can be used to create backups of MySQL databases in various formats, including SQL, CSV, and XML. The syntax for using mysqldump is as follows:
mysqldump [OPTIONS] database [tables]
In the syntax above, OPTIONS refers to the various options available for the mysqldump command, database is the name of the database you want to back up, and tables refers to the specific tables within the database that you want to back up.
To create a backup of an entire MySQL database, you can use the following command:
mysqldump -u [username] -p [password] [database] > [backup_file].sql
In the command above, replace [username] with the username of the MySQL user that has permission to access the database, [password] with the password for that user, [database] with the name of the database you want to back up, and [backup_file] with the name of the file you want to save the backup to.
To create a backup of specific tables within a MySQL database, you can use the following command:
mysqldump -u [username] -p [password] [database] [table1] [table2] > [backup_file].sql
In the command above, replace [table1] and [table2] with the names of the tables you want to back up.
Options
The following table lists the available options for the mysqldump command:
| Option | Description |
|---|---|
| -u, –user | The MySQL user to use when connecting to the database |
| -p, –password | The password for the MySQL user |
| -h, –host | The MySQL server to connect to |
| –port | The port number to use when connecting to the MySQL server |
| –default-character-set | The character set to use for the backup file |
| –single-transaction | Creates a consistent backup of the database while it is still running |
| –routines | Includes stored procedures and functions in the backup |
| –triggers | Includes triggers in the backup |
| –events | Includes events in the backup |
| –add-drop-database | Adds a DROP DATABASE statement before each CREATE DATABASE statement in the backup |
| –add-drop-table | Adds a DROP TABLE statement before each CREATE TABLE statement in the backup |
| –add-drop-trigger | Adds a DROP TRIGGER statement before each CREATE TRIGGER statement in the backup |
| –add-drop-view | Adds a DROP VIEW statement before each CREATE VIEW statement in the backup |
Troubleshooting Tips
Here are some common issues you may encounter when using the mysqldump command and how to troubleshoot them:
- Access denied for user ‘root’@’localhost’ (using password: YES): This error occurs when the MySQL user specified in the mysqldump command does not have permission to access the database. Check that the user has the correct permissions and that the password is correct.
- mysqldump: Got error: 1049: Unknown database ‘[database]’ when selecting the database: This error occurs when the database specified in the mysqldump command does not exist. Check that you have typed the correct database name.
- mysqldump: Error 2013: Lost connection to MySQL server during query when dumping table
[table]at row: [row_number]: This error occurs when the connection to the MySQL server is lost during the backup process. Try increasing the--max-allowed-packetoption to a higher value to allow for larger packets to be sent.
Notes
- The mysqldump command creates a logical backup of the MySQL database, which means that it creates a text file that contains SQL statements that can be used to recreate the database.
- The backup file created by mysqldump can be used to restore the database to its original state or to transfer the database to a different server.
- It is recommended to use the
--single-transactionoption when creating backups of InnoDB tables to ensure data consistency.