Restoring Individual Tables¶
With Percona XtraBackup, you can export individual tables from any InnoDB database, and
import them into Percona Server for MySQL with XtraDB or MySQL 5.7. The source does not
need to be XtraDB or MySQL 5.7 but the destination must be. This operation only works on
individual .ibd files. A table that is not contained in its own .ibd file cannot be exported.
Let’s see how to export and import the following table:
CREATE TABLE export_test (
a int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Exporting the Table¶
This table should have been created in innodb_file_per_table mode, so
after taking a backup as usual with xtrabackup --backup, the
.ibd file should exist in the target directory:
$ find /data/backups/mysql/ -name export_test.*
/data/backups/mysql/test/export_test.ibd
when you prepare the backup, add the extra parameter
xtrabackup --export to the command. Here is an example:
$ xtrabackup --prepare --export --target-dir=/data/backups/mysql/
Note
If you’re trying to restore encrypted InnoDB tablespace table you must specify the keyring file as well:
xtrabackup --prepare --export --target-dir=/tmp/table \
--keyring-file-data=/var/lib/mysql-keyring/keyring
Now you should see a .exp file in the target directory:
$ find /data/backups/mysql/ -name export_test.*
/data/backups/mysql/test/export_test.exp
/data/backups/mysql/test/export_test.ibd
/data/backups/mysql/test/export_test.cfg
These three files are all you need to import the table into a server running
Percona Server for MySQL with XtraDB or MySQL 5.7. In case server is using InnoDB
Tablespace Encryption
additional .cfp file be listed for encrypted tables.
Note
MySQL uses .cfg file which contains InnoDB dictionary dump in special format. This format is different from the .exp\ one which is used in XtraDB for the same purpose. Strictly speaking, a .cfg\ file is not required to import a tablespace to MySQL 5.7 or Percona Server for MySQL 5.7. A tablespace will be imported successfully even if it is from another server, but InnoDB will do schema validation if the corresponding .cfg file is present in the same directory.
Importing the Table¶
On the destination server, create a table with the same structure, and then perform the following steps:
-
Execute
ALTER TABLE test.export_test DISCARD TABLESPACE;- If you see the
ERROR 1030 (HY000): Got error -1 from storage enginemessage, then enable innodb_file_per_table and create the table again:
- If you see the
-
Copy the exported files to the
test/subdirectory of the destination server’s data directory -
Execute
ALTER TABLE test.export_test IMPORT TABLESPACE;
The table should now be imported, and you should be able to SELECT from it
and see the imported data.
Note
Persistent statistics for imported tablespace will be empty until you run the ANALYZE TABLE on the imported table. They are empty because they are stored in the system tables mysql.innodb_table_stats and mysql.innodb_index_stats and they are not updated by server during the import. This is due to upstream bug #72368.
