A database is classified into a main memory database and a disk database, depending on a main storage location of data. The main memory database locates data on a main memory to minimize disk input/output (I/O), thereby showing a higher performance than that of the disk database.
A main object of the database is to store data and there are several solutions to cope with loss of data. A representative solution is to back up data. However, when data is backed up, lots of data needs to be read and rewritten, so that lots of I/O is generated, which may lower a performance.
Further, in order to store the data, there is a solution which generates a data change history as a log to store the log as a separate file. When data is lost, the data may be restored through a log including a data change history. According to a solution which copes with the data loss through the log, the log is generated whenever the data is changed, so that the I/O generated at one time is not so large. However, since the log includes all change histories of data, in the database in which data is frequently changed, a log size is indefinitely increased. In order to store the data, the data backup and the log generating solution may be combined to be used.
Accordingly, there may be a demand for a method which appropriately reduces the log size in this technical field.
U.S. Pat. No. 8,977,597 discloses a method of generating a redo record before committing a transaction.