The Ultimate Guide to High Availability with MariaDB

Restoring Individual Tables and Partitions with Mariabackup

Contents

  1. Preparing the Backup
  2. Restoring the Backup
    1. Restoring Individual Non-Partitioned Tables
    2. Restoring Individual Partitions and Partitioned Tables

When using Mariabackup, you don't necessarily need to restore every table and/or partition that was backed up. Even if you're starting from a full backup, it is certainly possible to restore only certain tables and/or partitions from the backup, as long as the table or partition involved is in an InnoDB file-per-table tablespace. This page documents how to restore individual tables and partitions.

Preparing the Backup

Before you can restore from a backup, you first need to prepare it to make the data files consistent. You can do so with the --prepare command option.

The ability to restore individual tables and partitions relies on InnoDB's transportable tablespaces. For MariaDB to import tablespaces like these, InnoDB looks for a file with a .cfg extension. For Mariabackup to create these files, you also need to add the --export option during the prepare step.

For example, you might execute the following command:

$ mariabackup --prepare --export \
   --target-dir=/var/mariadb/backup/ \
   --user=mariabackup --password=mypassword

If this operation completes without error, then the backup is ready to be restored.

MariaDB until 10.2.8

Before MariaDB 10.2.9, Mariabackup did not support the --export option. See MDEV-13466 about that. In earlier versions of MariaDB, this means that Mariabackup could not create .cfg files for InnoDB file-per-table tablespaces during the --prepare stage. You can still import file-per-table tablespaces without the .cfg files in many cases, so it may still be possible in those versions to restore partial backups or to restore individual tables and partitions with just the .ibd files. If you have a full backup and you need to create .cfg files for InnoDB file-per-table tablespaces, then you can do so by preparing the backup as usual without the --export option, and then restoring the backup, and then starting the server. At that point, you can use the server's built-in features to copy the transportable tablespaces.

Restoring the Backup

The restore process for restoring individual tables and/or partitions is quite different than the process for full backups.

Rather than using the --copy-back or the --move-back, each individual InnoDB file-per-table tablespace file will have to be manually imported into the target server. The process that is used to restore the backup will depend on whether partitioning is involved.

Restoring Individual Non-Partitioned Tables

To restore individual non-partitioned tables from a backup, find the .ibd and .cfg files for the table in the backup, and then import them using the Importing Transportable Tablespaces for Non-partitioned Tables process.

Restoring Individual Partitions and Partitioned Tables

To restore individual partitions or partitioned tables from a backup, find the .ibd and .cfg files for the partition(s) in the backup, and then import them using the Importing Transportable Tablespaces for Partitioned Tables process.

Comments

Comments loading...
Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.