Checkpointing for distributed databases: starting from the basics

Checkpointing in a distributed database system is analyzed by establishing a correspondence between consistent snapshots in a general distributed system and transaction-consistent checkpoints in a distributed database system. The analysis culminates in a useful condition for transaction-consistent checkpoints. Based on this condition, a general checkpointing scheme, which records a transaction-consistent set of values of all or some selected data items is presented. These rules are implemented in some representative concurrency control protocols, i.e., those based on two-phase locking and timestamping. These implementations cause little interference with other activities in the database system