2.8.2 Database updating method
HADB uses the write-once updating method as the database updating method.
With the write-once updating method, when a row is deleted it becomes invalid but is not physically deleted from the disk. Likewise, when a row is updated it becomes invalid and a new, updated, row is added. The original row that became invalid is not physically deleted from the disk.
If you delete a row by executing the TRUNCATE TABLE data manipulation SQL statement, the segment is released and the row is deleted from the disk.