Function

The retention period of multiversion backup data takes effect each time the insert overwrite or truncate statement is executed. If neither statement is executed for the table, multiversion backup data out of the retention period will not be automatically deleted. You can run the SQL commands described in this section to manually delete multiversion backup data.

Syntax

Delete multiversion backup data out of the retention period.

clear history for table [db_name.]table_name older_than 'timestamp';

Keywords

clear history for table: Used to delete multiversion backup data
older_than: Used to specify the time range for deleting multiversion backup data

Parameters

**Table 1** Parameters
Parameter	Description
db_name	Database name, which consists of letters, digits, and underscores (_). The value cannot contain only digits or start with a digit or underscore (_).
table_name	Table name
Timestamp	Multiversion backup data generated before the timestamp will be deleted. Timestamp format: yyyy-MM-dd HH:mm:ss

Precautions

Currently, the multiversion function supports only OBS tables created using the Hive syntax. For details about the syntax for creating a table, see Creating an OBS Table Using the Hive Syntax.
This statement does not delete the backup data of the current version.

Example

Delete the multiversion backup data generated before 2021-09-25 23:59:59 in the dliTable table. When the multiversion backup data is generated, a timestamp is generated.