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TiDB Snapshot Backup and Restore Command Manual |
TiDB Snapshot Backup and Restore Command Manual describes commands for backing up and restoring cluster snapshots, databases, and tables. It also covers encrypting backup data and restoring encrypted snapshots. The BR tool supports self-adapting to GC and introduces the --ignore-stats parameter for backing up and restoring statistics. It also supports encrypting backup data and restoring partial data of specified databases or tables. |
This document describes the commands of TiDB snapshot backup and restore according to the application scenarios, including:
- Back up cluster snapshots
- Back up a database or a table
- Back up statistics
- Encrypt the backup data
- Restore cluster snapshots
- Restore a database or a table
- Restore encrypted snapshots
For more information about snapshot backup and restore, refer to:
You can back up the latest or specified snapshot of the TiDB cluster using the br backup full
command. For more information about the command, run the br backup full --help
command.
br backup full \
--pd "${PD_IP}:2379" \
--backupts '2022-09-08 13:30:00' \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--ratelimit 128 \
--log-file backupfull.log
In the preceding command:
--backupts
: The time point of the snapshot. The format can be TSO or timestamp, such as400036290571534337
or2018-05-11 01:42:23
. If the data of this snapshot is garbage collected, thebr backup
command returns an error and 'br' exits. If you leave this parameter unspecified,br
picks the snapshot corresponding to the backup start time.--ratelimit
: The maximum speed per TiKV performing backup tasks. The unit is in MiB/s.--log-file
: The target file wherebr
log is written.
Note:
The BR tool already supports self-adapting to GC. It automatically registers
backupTS
(the latest PD timestamp by default) to PD'ssafePoint
to ensure that TiDB's GC Safe Point does not move forward during the backup, thus avoiding manually setting GC configurations.
During backup, a progress bar is displayed in the terminal, as shown below. When the progress bar advances to 100%, the backup is complete.
Full Backup <---------/................................................> 17.12%.
Backup & Restore (BR) supports backing up partial data of a specified database or table from a cluster snapshot or incremental data backup. This feature allows you to filter out unwanted data from snapshot backup and incremental data backup, and back up only business-critical data.
To back up a database in a cluster, run the br backup db
command.
The following example backs up the test
database to Amazon S3:
br backup db \
--pd "${PD_IP}:2379" \
--db test \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--ratelimit 128 \
--log-file backuptable.log
In the preceding command, --db
specifies the database name, and other parameters are the same as those in Back up TiDB cluster snapshots.
To back up a table in a cluster, run the br backup table
command.
The following example backs up the test.usertable
table to Amazon S3:
br backup table \
--pd "${PD_IP}:2379" \
--db test \
--table usertable \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--ratelimit 128 \
--log-file backuptable.log
In the preceding command, --db
and --table
specify the database name and table name respectively, and other parameters are the same as those in Back up TiDB cluster snapshots.
To back up multiple tables with more criteria, run the br backup full
command and specify the table filters with --filter
or -f
.
The following example backs up tables that match the db*.tbl*
filter rule to Amazon S3:
br backup full \
--pd "${PD_IP}:2379" \
--filter 'db*.tbl*' \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--ratelimit 128 \
--log-file backupfull.log
Starting from TiDB v7.5.0, the br
command-line tool introduces the --ignore-stats
parameter. When you set this parameter to false
, the br
command-line tool supports backing up and restoring statistics of columns, indexes, and tables. In this case, you do not need to manually run the statistics collection task for the TiDB database restored from the backup, or wait for the completion of the automatic collection task. This feature simplifies the database maintenance work and improves the query performance.
If you do not set this parameter to false
, the br
command-line tool uses the default setting --ignore-stats=true
, which means statistics are not backed up during data backup.
The following is an example of backing up cluster snapshot data and backing up table statistics with --ignore-stats=false
:
br backup full \
--storage local:///br_data/ --pd "${PD_IP}:2379" --log-file restore.log \
--ignore-stats=false
After backing up data with the preceding configuration, when you restore data, the br
command-line tool automatically restores table statistics if table statistics are included in the backup:
br restore full \
--storage local:///br_data/ --pd "${PD_IP}:2379" --log-file restore.log
When the backup and restore feature backs up data, it stores statistics in JSON format within the backupmeta
file. When restoring data, it loads statistics in JSON format into the cluster. For more information, see LOAD STATS.
Warning:
This is an experimental feature. It is not recommended that you use it in the production environment.
BR supports encrypting backup data at the backup side and at the storage side when backing up to Amazon S3. You can choose either encryption method as required.
Since TiDB v5.3.0, you can encrypt backup data by configuring the following parameters:
--crypter.method
: Encryption algorithm, which can beaes128-ctr
,aes192-ctr
, oraes256-ctr
. The default value isplaintext
, indicating that data is not encrypted.--crypter.key
: Encryption key in hexadecimal string format. It is a 128-bit (16 bytes) key for the algorithmaes128-ctr
, a 24-byte key for the algorithmaes192-ctr
, and a 32-byte key for the algorithmaes256-ctr
.--crypter.key-file
: The key file. You can directly pass in the file path where the key is stored as a parameter without passing in thecrypter.key
.
The following is an example:
br backup full\
--pd ${PD_IP}:2379 \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--crypter.method aes128-ctr \
--crypter.key 0123456789abcdef0123456789abcdef
Note:
- If the key is lost, the backup data cannot be restored to the cluster.
- The encryption feature needs to be used on
br
and TiDB clusters v5.3.0 or later versions. The encrypted backup data cannot be restored on clusters earlier than v5.3.0.
You can restore a TiDB cluster snapshot by running the br restore full
command.
br restore full \
--pd "${PD_IP}:2379" \
--with-sys-table \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--ratelimit 128 \
--log-file restorefull.log
In the preceding command:
--with-sys-table
: BR restores data in some system tables, including account permission data and SQL bindings, and statistics (see Back up statistics). However, it does not restore statistics tables (mysql.stat_*
) and system variable tables (mysql.tidb
andmysql.global_variables
). For more information, see Restore tables in themysql
schema.--ratelimit
: The maximum speed per TiKV performing backup tasks. The unit is in MiB/s.--log-file
: The target file where thebr
log is written.
During restore, a progress bar is displayed in the terminal as shown below. When the progress bar advances to 100%, the restore task is completed. Then br
will verify the restored data to ensure data security.
Full Restore <---------/...............................................> 17.12%.
You can use br
to restore partial data of a specified database or table from backup data. This feature allows you to filter out data that you do not need during the restore.
To restore a database to a cluster, run the br restore db
command.
The following example restores the test
database from the backup data to the target cluster:
br restore db \
--pd "${PD_IP}:2379" \
--db "test" \
--ratelimit 128 \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--log-file restore_db.log
In the preceding command, --db
specifies the name of the database to be restored and other parameters are the same as those in Restore TiDB cluster snapshots.
Note:
When you restore the backup data, the database name specified by
--db
must be the same as the one specified by-- db
in the backup command. Otherwise, the restore fails. This is because the metafile of the backup data (backupmeta
file) records the database name, and you can only restore data to the database with the same name. The recommended method is to restore the backup data to the database with the same name in another cluster.
To restore a single table to a cluster, run the br restore table
command.
The following example restores the test.usertable
table from Amazon S3 to the target cluster:
br restore table \
--pd "${PD_IP}:2379" \
--db "test" \
--table "usertable" \
--ratelimit 128 \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--log-file restore_table.log
In the preceding command, --table
specifies the name of the table to be restored, and other parameters are the same as those in Restore a database.
To restore multiple tables with more complex filter rules, run the br restore full
command and specify the table filters with --filter
or -f
.
The following example restores tables that match the db*.tbl*
filter rule from Amazon S3 to the target cluster:
br restore full \
--pd "${PD_IP}:2379" \
--filter 'db*.tbl*' \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--log-file restorefull.log
To restore execution plan bindings of a cluster, you can run the br restore full
command, including the --with-sys-table
option and also the --filter
or -f
option to specify the mysql
schema to be restored.
The following is an example of restoring the mysql.bind_info
table:
br restore full \
--pd "${PD_IP}:2379" \
--filter 'mysql.bind_info' \
--with-sys-table \
--ratelimit 128 \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--log-file restore_system_table.log
After the restore is completed, you can confirm the execution plan binding information with SHOW GLOBAL BINDINGS
:
SHOW GLOBAL BINDINGS;
The dynamic loading of execution plan bindings after the restore is still undergoing optimization (related issues are #46527 and #46528). You need to manually reload the execution plan bindings after the restore.
-- Ensure that the mysql.bind_info table has only one record for builtin_pseudo_sql_for_bind_lock. If there are more records, you need to manually delete them.
SELECT count(*) FROM mysql.bind_info WHERE original_sql = 'builtin_pseudo_sql_for_bind_lock';
DELETE FROM bind_info WHERE original_sql = 'builtin_pseudo_sql_for_bind_lock' LIMIT 1;
-- Force to reload the binding information.
ADMIN RELOAD BINDINGS;
Warning:
This is an experimental feature. It is not recommended that you use it in the production environment.
After encrypting the backup data, you need to pass in the corresponding decryption parameters to restore the data. Ensure that the decryption algorithm and key are correct. If the decryption algorithm or key is incorrect, the data cannot be restored. The following is an example:
br restore full\
--pd "${PD_IP}:2379" \
--storage "s3://${backup_collection_addr}/snapshot-${date}?access-key=${access-key}&secret-access-key=${secret-access-key}" \
--crypter.method aes128-ctr \
--crypter.key 0123456789abcdef0123456789abcdef