An Optimized Backout Mechanism For Sequential Updates

It has been recently show that the technique of periodic updating of a key-sorted data base from a key-sorted "transaction file" may be considered to be used even in online data bases. In this paper, a backout mechanism is described which exploits the special characteristics of this technique thus, adding new arguments to justify the employnent of an option for batch and sequential updates in data bases. A formula is developed to enable the user to tune this backout mechanism according to parameters that characterize his application and his installation. The backout mechanism described here is implemented at the Weizmann Institut in its DB1 data base applications management system (DBAMS).