diff --git a/br/use-br-command-line-tool.md b/br/use-br-command-line-tool.md index 25fc603e680d..fc58c8dad0b3 100644 --- a/br/use-br-command-line-tool.md +++ b/br/use-br-command-line-tool.md @@ -438,6 +438,39 @@ In the above command, `--table` specifies the name of the table to be restored. Restoring incremental data is similar to [restoring full data using BR](#restore-all-the-backup-data). Note that when restoring incremental data, make sure that all the data backed up before `last backup ts` has been restored to the target cluster. +### Restore tables created in `mysql` database (experimental feature) + +BR backups tables created in `mysql` database by default. + +When you are restoring data using BR, the tables created in `mysql` database are not restored by default. If you need to restore them, explicitly contain them using [table filter](/table-filter.md#syntax). The following example restores `mysql.usertable` created in `mysql` database. The command restores `mysql.usertable` and other data at the same time. + +{{< copyable "shell-regular" >}} + +```shell +br restore full -f '*.*' -f '!mysql.*' -f 'mysql.usertable' -s $external_storage_url +``` + +In the above command, `-f '*.*'` is used to cover the default rules and `-f '!mysql.*'` instructs BR not to restore tables in `mysql` unless otherwise stated. `-f 'mysql.usertable'` indicates that `mysql.usertable` is required to be restored. For details, refer to [table filter document](/table-filter.md#syntax). + +If you only need to restore `mysql.usertable`, use the following command: + +{{< copyable "shell-regular" >}} + +```shell +br restore full -f 'mysql.usertable' -s $external_storage_url +``` + +> **Warning:** +> +> Although you can back up and restore system tables (such as `mysql.tidb`) using BR tools, some unexpected conditions might appear after the restore. The known exceptions are as follows: +> +> - statistics information table (`mysql.stat_*`) cannot be restored. +> - system variable table (`mysql.tidb`,`mysql.global_variables`) cannot be restored. +> - user information table (such as `mysql.user`,`mysql.columns_priv`) cannot be restored. +> - GC data cannot be restored. +> +> For restoring system tables, more compatibility issues might occur. To avoid something unexpected, do not restore system tables in the production enviroment. + ### Restore Raw KV (experimental feature) > **Warning:**