恢复租户

为防止恶意或误操作导致的数据不可恢复性丢失，OceanBase 数据库提供了回收站功能，从而支持租户级的数据的快速恢复功能。本文介绍如何恢复回收站中的租户。

OceanBase 数据库可以通过 FLASHBACK TENANT 语句恢复回收站中的租户。

使用限制

由于当前仅 sys 租户可以删除租户，故 MySQL 模式和 Oracle 模式的租户被删除后，只能进入 sys 租户的回收站中。也只有 sys 租户可以执行恢复租户的操作。

操作步骤

1. 使用 root 用户登录到集群的 sys 租户。

   obclient -h172.30.xx.xx -P2883 -uroot@sys#cluster -p**** -A

2. 进入 oceanbase 数据库。

   obclient [(none)]> USE oceanbase;

3. 通过 SHOW RECYCLEBIN 语句，查看当前系统租户回收站中的对象。

   obclient [oceanbase]> SHOW RECYCLEBIN;
   +-------------------------------------+---------------+--------+----------------------------+
   | OBJECT_NAME                         | ORIGINAL_NAME | TYPE   | CREATETIME                 |
   +-------------------------------------+---------------+--------+----------------------------+
   | __recycle_$_100017_1673367572701376 | mq_t1         | TENANT | 2023-01-11 00:23:36.317242 |
   +-------------------------------------+---------------+--------+----------------------------+
   1 row in set
   

   回收站相关参数的详细说明，参见 recyclebin。

4. 通过 FLASHBACK TENANT 语句，恢复回收站中的租户。

   以恢复租户 mq_t1 为例：

   obclient [oceanbase]> FLASHBACK TENANT mq_t1 TO BEFORE DROP;
   Query OK, 0 rows affected
   

   FLASHBACK TENANT 语句的详细说明，参见 FLASHBACK。

5. 查看 DBA_OB_TENANTS 视图和回收站确认执行结果。

obclient [oceanbase]> SHOW RECYCLEBIN;
Empty set

obclient [oceanbase]> SELECT * FROM DBA_OB_TENANTS WHERE TENANT_NAME = 'mq_t1';
+-----------+-------------+-------------+----------------------------+----------------------------+--------------+------------------------------+-------------------+--------------------+--------+---------------+--------+-------------+-------------------+------------------+---------------------+---------------------+---------------------+---------------------+--------------+----------------------------+
| TENANT_ID | TENANT_NAME | TENANT_TYPE | CREATE_TIME                | MODIFY_TIME                | PRIMARY_ZONE | LOCALITY                     | PREVIOUS_LOCALITY | COMPATIBILITY_MODE | STATUS | IN_RECYCLEBIN | LOCKED | TENANT_ROLE | SWITCHOVER_STATUS | SWITCHOVER_EPOCH | SYNC_SCN            | REPLAYABLE_SCN      | READABLE_SCN        | RECOVERY_UNTIL_SCN  | LOG_MODE     | ARBITRATION_SERVICE_STATUS |
+-----------+-------------+-------------+----------------------------+----------------------------+--------------+------------------------------+-------------------+--------------------+--------+---------------+--------+-------------+-------------------+------------------+---------------------+---------------------+---------------------+---------------------+--------------+----------------------------+
|      1036 | mq_t1       | USER        | 2023-01-11 00:23:36.317242 | 2023-05-18 15:49:12.857944 | zone1;zone2  | FULL{1}@zone1, FULL{1}@zone2 | NULL              | MYSQL              | NORMAL | NO            | NO     | PRIMARY     | NORMAL            |                0 | 1684396167132057328 | 1684396167132057328 | 1684396167051160964 | 4611686018427387903 | NOARCHIVELOG | DISABLED                   |
+-----------+-------------+-------------+----------------------------+----------------------------+--------------+------------------------------+-------------------+--------------------+--------+---------------+--------+-------------+-------------------+------------------+---------------------+---------------------+---------------------+---------------------+--------------+----------------------------+
1 row in set