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-7th Edition 19.3 ©Silberscha乜，Korth and SudarshanDatabase System Concepts - 7 19.3 ©Silberschatz, Korth and Sudarshan th Edition 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