Failure Classification Transaction failure: Logical errors:transaction cannot complete due to some internal error condition System errors:the database system must terminate an active transaction due to an error condition(e.g.,deadlock) System crash:a power failure or other hardware or software failure causes the system to crash. Fail-stop assumption:non-volatile storage contents are assumed to not be corrupted by system crash Database systems have numerous integrity checks to prevent corruption of disk data Disk failure:a head crash or similar disk failure destroys all or part of disk storage Destruction is assumed to be detectable:disk drives use checksums to detect failures Database System Concepts,5th Edition,Oct 5,2006 17.3 ©Silberschat乜，Korth and SudarshanDatabase System Concepts, 5 17.3 ©Silberschatz, Korth and Sudarshan th Edition, Oct 5, 2006 Failure Classification Transaction failure : Logical errors: transaction cannot complete due to some internal error condition System errors: the database system must terminate an active transaction due to an error condition (e.g., deadlock) System crash: a power failure or other hardware or software failure causes the system to crash. Fail-stop assumption: non-volatile storage contents are assumed to not be corrupted by system crash  Database systems have numerous integrity checks to prevent corruption of disk data Disk failure: a head crash or similar disk failure destroys all or part of disk storage Destruction is assumed to be detectable: disk drives use checksums to detect failures