31 Aug 2021

Backup and restore MySQL databases in an efficient way

mysqldump allows us to create logical backups of our databases, as well as restoring them.

A logical backup uses SQL statements to create the contents of the database, such as tables, views, triggers and inserts the data using the INSERT statement.

For example:

CREATE TABLE `users` (
  `id` bigint unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `email` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `email_verified_at` timestamp NULL DEFAULT NULL,
  `password` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `two_factor_secret` text COLLATE utf8mb4_unicode_ci,
  `two_factor_recovery_codes` text COLLATE utf8mb4_unicode_ci,
  `remember_token` varchar(100) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `current_team_id` bigint unsigned DEFAULT NULL,
  `profile_photo_path` varchar(2048) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `is_admin` tinyint(1) DEFAULT NULL,
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `users_email_unique` (`email`)

INSERT INTO `users` (`id`, `name`, `email`, `email_verified_at`, `password`, `two_factor_secret`, `two_factor_recovery_codes`, `remember_token`, `current_team_id`, `profile_photo_path`, `is_admin`, `created_at`, `updated_at`) VALUES
(1, 'Prof. Norwood Moen', 'moen@example.com', '2021-08-28 20:39:31', '$2y$10$92IXUNpkjO0rOQ5byMi.Ye4oKoEa3Ro9llC/.og/at2.uheWG/igi', NULL, NULL, 'Ji0Eqw70n1', NULL, NULL, 1, '2021-08-28 20:39:31', '2021-08-28 20:39:31');

In this post, I will show you how to backup MySQL using mysqldump in an efficient way.

Basic of mysqldump

You can easily backup your database using the following command:

mysqldump your_database > database.sql

To make the backup file smaller, we may compress it using gzip :

mysqldump mysql | gzip > database.sql.gz

gzip is a great tool, but it doesn't work properly on a multi-core system.


An alternative tool to gzip is pigz which stands for parallel Implementation of gzip.

pigz exploits multiple processors and multiple cores to the hilt when compressing data [Source]:

sudo apt-get install -y pigz

mysqldump mysql | pigz > database.sql.gz

Data Inconsistency

Let's say that your database has users and posts tables, then what happens if the users table is dumped out, a new user is created before the posts table is dumped?

As you can probably tell, mysqldump will export inconsistent data, it will have a post related to a user that doesn't exist.

We can easily get around this issue by running the export operation within a transaction, which keeps our data inconsistent:

mysqldump -u your_user -p --single-transaction \
    --default-character-set=utf8mb4 \
    your_database | pigz > database.sql.gz

Restore database

Let's see how to restore the database:

gunzip < database_file.sql.gz | mysql -u your_user -p your_database

That's it 🥳