Consistent checkpointing for transaction systems

Whether it is for audit or for recovery purposes, data checkpointing is an important problem of transaction systems. Actually, transactions establish dependence relations on data checkpoints taken by data object managers. So, given an arbitrary set of data checkpoints (including at least a single data checkpoint from a data manager, and at mast a data checkpoint from each data manager), an important question is the following one: 'Can these data checkpoints be members of a same consistent global checkpoint?' This paper answers this question by providing a necessary and sufficient condition suited to transaction systems, Moreover, to show its usefulness, two non-intrusive data checkpointing protocols are designed from this condition.