rollbackcaching

Rollback caching refers to a caching technique used in data stores and applications to allow the cached data to be reverted to a previously saved state when a transaction is aborted, fails, or requires a rollback. The goal is to preserve cache consistency with the primary data state without necessitating a full reload from the source store.

Mechanisms commonly employed include write-ahead logs of cache mutations, shadow or duplicate caches, and versioned cache entries. In a write-ahead approach, changes are recorded in a log or meta-structure before being applied to the cache, enabling reversal by replaying or reversing the log. Shadow caching maintains a parallel cache state that can be swapped in when a rollback is required. Versioned caches attach a version or timestamp to each entry, and rollback involves restoring a prior version.

Operation typically involves associating a transactional boundary with cache updates. On commit, the cache state is promoted to the new committed version. On rollback, the system reverts the cache to the last known good state, either by applying a reverse log, restoring a shadow snapshot, or discarding uncommitted versions. This can improve latency by avoiding full data reloads while maintaining consistency between the cache and the underlying store during complex workflows.

Variants vary in complexity and overhead. Rollback caching can reduce cache-related inconsistencies in long-running transactions, multi-step workflows, and systems requiring stronger cache coherence. Trade-offs include added storage for logs or snapshots, increased write latency, and more sophisticated synchronization between the cache and the data store.

See also: caching, database transactions, cache coherence.