Implementation of Atomicity and durability (Cont) The shadow-database scheme db_pointer db pointer old copy o old opy database database new copy of (to be deleted) database (a)Before update (b)After update Assumes disks to not fail Useful for text editors, but extremely inefficient for large databases: executing a single transaction requires copying the entire database. Will see better schemes in Chapter 17 Database System Concepts 15.9 OSilberschatz. Korth and SudarshanDatabase System Concepts 15.9 ©Silberschatz, Korth and Sudarshan Implementation of Atomicity and Durability (Cont.) Assumes disks to not fail Useful for text editors, but extremely inefficient for large databases: executing a single transaction requires copying the entire database. Will see better schemes in Chapter 17. The shadow-database scheme: