--- title: "FLASHBACK - OceanBase 数据库 V4.1.0 | OceanBase 文档中心" description: "FLASHBACK 描述 该语句用于从回收站中恢复被删除的数据库对象，包括租户、数据库、表等。 默认情况下，回收站处于开启状态，该行为由系统变量 recyclebin 控制。您可以通过 SHOW VARIABLES LIKE 'recyclebin' 查看回收站是否开启。有关系统变量 recyclebin 的详细信息…" --- 切换语言 - 中文站 - 简体中文 - International - English - 日本站 - 日本語 文档反馈![](https://mdn.alipayobjects.com/huamei_22khvb/afts/img/A*P8CuR4UJ_FkAAAAAAAAAAAAADiGDAQ/original) OceanBase 数据库分布式版 - V 4.1.0 # FLASHBACK 更新时间：2023-07-28 10:45:58 [编辑](https://github.com/oceanbase/oceanbase-doc/edit/V4.1.0/zh-CN/700.reference/400.development-reference/100.sql-syntax/200.common-tenant-of-mysql-mode/600.sql-statement-of-mysql-mode/5400.flashback-database-of-mysql-mode.md) ## 描述 该语句用于从回收站中恢复被删除的数据库对象，包括租户、数据库、表等。 默认情况下，回收站处于开启状态，该行为由系统变量 `recyclebin` 控制。您可以通过 `SHOW VARIABLES LIKE 'recyclebin'` 查看回收站是否开启。有关系统变量 `recyclebin` 的详细信息，请参见《参考指南》中的 **系统变量** 章节。 ```sql obclient> SHOW VARIABLES LIKE 'recyclebin'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | recyclebin | ON | +---------------+-------+ 1 row in set ``` 如果回收站处于关闭状态，可以通过 `SET recyclebin = on` 语句开启回收站。回收站中的数据库对象没有被实际删除，仍然会占用资源，如果需要彻底删除，可以执行 `PUREGE recyclebin` 语句清理回收站。 在删除表后，会同时也会删除从属该表的索引，在通过 `FLASHBACK` 语句恢复表时，表上的索引也会恢复。特别地，从表中直接删除的索引不会进入回收站，OceanBase 数据库也不支持从回收站中直接回收索引。 ## 语法 ```sql FLASHBACK {TENANT | DATABASE | TABLE} object_name TO BEFORE DROP [RENAME TO flashback_object_name]; flashback_object_name: tenant_name | database_name | database_name.table_name ``` ## 参数解释 | **参数** | **解释** | | --- | --- | | object_name | 指定要恢复的数据库对象在回收站中的名称，不支持直接指定名称。 恢复数据库对象时，也会将从属于数据库的表、索引等数据库对象一并恢复。 您可以通过 `SHOW RECYCLEBIN` 语句查看要恢复的数据库在回收站中的名称。 | | RENAME to | 恢复时将数据库对象重命名。 | | tenant_name | 租户恢复后的名称。 | | database_name | 数据库恢复后的名称 | | database_name.table_name | 表恢复后的名称，其中 `database_name` 用于指定表恢复后的从属的数据库。 | ## 示例 - 从回收站中恢复被删除的租户 `tenant1`。 ```sql obclient> FLASHBACK TENANT tenant1 TO BEFORE DROP; Query OK, 0 rows affected ``` - 从回收站中恢复删除的数据库。 ```sql obclient> CREATE DATABASE da; Query OK, 1 row affected obclient> DROP DATABASE da; Query OK, 0 rows affected obclient> SHOW RECYCLEBIN; +--------------------------------------------------+---------------+----------+----------------------------+ | OBJECT_NAME | ORIGINAL_NAME | TYPE | CREATETIME | +--------------------------------------------------+---------------+----------+----------------------------+ | __recycle_$_1_1099511628829_18446744073709551615 | da | DATABASE | 2017-10-20 17:36:15.838771 | +--------------------------------------------------+---------------+----------+----------------------------+ 1 row in set obclient> FLASHBACK DATABASE __recycle_$_1_1099511628829_18446744073709551615 TO BEFORE DROP; Query OK, 0 rows affected ``` - 从回收站中恢复被删除的表 `t1`，重命名为 `t2`，并查看索引的恢复情况。 ```sql obclient> CREATE TABLE t1(c1 INT PRIMARY KEY,c2 INT,c3 INT); Query OK, 0 rows affected obclient> ALTER TABLE t1 ADD INDEX ind2 (c2) USING BTREE; Query OK, 0 rows affected obclient> ALTER TABLE t1 ADD INDEX ind3 (c3) USING BTREE; Query OK, 0 rows affected obclient> SHOW INDEX FROM t1; +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+-----------+---------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+-----------+---------------+---------+ | t1 | 0 | PRIMARY | 1 | c1 | A | NULL | NULL | NULL | | BTREE | available | | YES | | t1 | 1 | ind2 | 1 | c2 | A | NULL | NULL | NULL | YES | BTREE | available | | YES | | t1 | 1 | ind3 | 1 | c3 | A | NULL | NULL | NULL | YES | BTREE | available | | YES | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+-----------+---------------+---------+ 3 rows in set obclient> ALTER TABLE t1 DROP INDEX ind2; Query OK, 0 rows affected obclient> SHOW RECYCLEBIN; Empty set obclient> DROP TABLE t1; Query OK, 0 rows affected obclient> SHOW RECYCLEBIN; +---------------------------------+--------------------------+-------+----------------------------+ | OBJECT_NAME | ORIGINAL_NAME | TYPE | CREATETIME | +---------------------------------+--------------------------+-------+----------------------------+ | __recycle_$_10_1628157070059520 | __idx_1099511677777_ind3 | INDEX | 2021-08-05 17:51:10.060761 | | __recycle_$_10_1628157070067712 | t1 | TABLE | 2021-08-05 17:51:10.068062 | +---------------------------------+--------------------------+-------+----------------------------+ 2 rows in set obclient> FLASHBACK TABLE __recycle_$_10_1628157070067712 TO BEFORE DROP RENAME TO t2; obclient> SHOW INDEX FROM t2; +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+-----------+---------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+-----------+---------------+---------+ | t2 | 0 | PRIMARY | 1 | c1 | A | NULL | NULL | NULL | | BTREE | available | | YES | | t2 | 1 | ind3 | 1 | c3 | A | NULL | NULL | NULL | YES | BTREE | available | | YES | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+-----------+---------------+---------+ 2 rows in set ``` 上一篇 下一篇 ![有帮助](https://gw.alipayobjects.com/mdn/ob_asset/afts/img/A*y6ocSqN8cqsAAAAAAAAAAAAAARQnAQ)![无帮助](https://gw.alipayobjects.com/mdn/ob_asset/afts/img/A*BG9IQJyLHF8AAAAAAAAAAAAAARQnAQ)![反馈](https://gw.alipayobjects.com/mdn/ob_asset/afts/img/A*eTWdQKCRKHwAAAAAAAAAAAAAARQnAQ)[AI](https://www.oceanbase.com/obi) 咨询热线