•At time of crash, an application program may be part-way through (and the data may not meet integrity constraints)
•Also, buffering can cause problems
–Note that system crash loses all buffered data, restart has only disk state
–Effects of a committed txn may be only in buffer, not yet recorded in disk state
–Lack of coordination between flushes of different buffered pages, so even if current state satisfies constraints, the disk state may not
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