Manually clear secondary backup data

You can manually clear secondary backup data as needed.

Preparations

Before you manually clear the expired secondary backup data, you must specify the expiration time and clearing policy of secondary backup data by setting recovery_window and auto_delete_obsolete_backup in the backup_backup_dest_option configuration item.

Example:

obclient> ALTER SYSTEM SET backup_backup_dest_option='recovery_window=14d&auto_delete_obsolete_backup=false';

In the example:

• recovery_window specifies the retention period of secondary backup data.

  If you do not specify this parameter in the backup_backup_dest_option configuration item, the value of the cluster-level configuration item backup_recovery_window is used by default. If you do not specify either backup_dest_option or backup_recovery_window, the default value 0 is used, indicating that secondary backup data will never expire. We recommend that you use backup_backup_dest_option to specify the retention period of secondary backup data.

  When the secondary backup expires, you can manually clear it.

• auto_delete_obsolete_backup specifies whether to automatically delete expired secondary backup data.

  If you do not specify this parameter in the backup_backup_dest_option configuration item, the value of the cluster-level configuration item auto_delete_expired_backup is used by default. If you do not specify either backup_dest_option or auto_delete_expired_backup, the default value false is used, indicating that expired backup data will not be automatically deleted. In this case, auto_delete_obsolete_backup must be set to false. We recommend that you use backup_backup_dest_option to specify whether to automatically clear expired backup data.

For more information about backup_backup_dest_option, see the "backup_backup_dest_option" topic in Reference Guide (MySQL Mode) or Reference Guide (Oracle Mode).

Clear the secondary backup of specified backups

1. Log on to the database as the root user of the sys tenant.

2. Query the CDB_OB_BACKUP_SET_DETAILS and CDB_OB_BACKUP_PIECE_FILES views to find the backup_set_id, copy_id, piece_id, and round_id corresponding to the backup data to be cleared.

   For more information about the fields in CDB_OB_BACKUP_SET_DETAILS and CDB_OB_BACKUP_PIECE_FILES, see the "oceanbase.CDB_OB_BACKUP_SET_DETAILS" and "oceanbase.CDB_OB_BACKUP_PIECE_FILES" topics in Reference Guide (MySQL Mode).

3. Select the command that is appropriate for your need to clear the secondary backup data.

   • Clear backups with the specified <backup_set_id,copy_id>

     obclient> ALTER SYSTEM DELETE BACKUPSET backup_set_id COPY copy_id;
     

     If the backup is not split into multiple backup pieces because the value of log_archive_piece_switch_interval in backup_dest_option is 0, clog data other than the valid backup will be deleted. If the backup file is split into multiple backup pieces because the value of log_archive_piece_switch_interval in backup_dest_option is not 0, the corresponding clog data will not be deleted. Notice

     Both full backups and incremental backups can be deleted by specifying their backup_set_id. Therefore, you need to ensure data integrity when you manually delete backups. If the backup that an incremental backup depends on is deleted, the corresponding backup set cannot be restored.

     When you use the DELETE BACKUPSET command to clear the secondary backups, the following constraints apply:

     • If the backup_dest of the <backup_set_id,copy_id> to be deleted is the same as the destination specified in the backup_backup_dest configuration item, at least one complete and valid backup copy is retained. Otherwise, the constraint of retaining one valid secondary backup copy does not apply.

     • If the backup_dest of the <backup_set_id,copy_id> to be deleted is the same as the destination specified in the backup_backup_dest configuration item, the <backup_set_id,copy_id> must be deleted in a specific order. Otherwise, the constraint on the deletion order of <backup_set_id,copy_id> does not apply.

     • The command fails if the specified <backup_set_id,copy_id> does not exist, or the backup of the specified <backup_set_id,copy_id> is still ongoing.

   • Clear archived data with the specified <piece_id,copy_id>

     obclient> ALTER SYSTEM DELETE BACKUPPIECE piece_id COPY copy_id;
     

     When you use the DELETE BACKUPPIECE command to clear the archived backup data, the following constraints apply:

     • You can only delete <piece_id,copy_id> in the Frozen or Inactive status.

     • If the backup_dest of the <piece_id,copy_id> to be deleted is the same as the destination specified in the backup_backup_dest configuration item, and the existing backups do not fully cover the backup piece, the corresponding <piece_id,copy_id> cannot be deleted. Otherwise, the corresponding <piece_id,copy_id> can be deleted regardless of whether the existing backups fully cover the backup piece.

     • If the backup_dest of the <piece_id,copy_id> to be deleted is the same as the destination specified in the backup_backup_dest configuration item, the <piece_id,copy_id> must be deleted in a specific order. Otherwise, the constraint on the deletion order of <piece_id,copy_id> does not apply.