Residobject

Residobject is a term used in some fault-tolerance and distributed systems discussions to denote a data structure that captures the residual state of a computation after partial execution, a failure, or a rollback. It aims to represent what remains to be computed, what partial results exist, and how to resume processing safely.

A residobject typically comprises several components: a preserved subset of the program state, a queue or list of pending operations, a replay or rewrite log describing how to reapply steps, and metadata such as version vectors or causal dependencies. Together, these elements enable reconstruction of the original execution or verification of correctness during recovery or auditing.

Semantics and use cases. In practice, residobjects support recovery from crashes, network partitions, or interrupted workflows by providing a compact bundle that can be replayed to reach a consistent end state. They are particularly relevant for long-running or stateful computations, streaming pipelines, and microservice orchestration, where restarting from the beginning would be expensive. Residobjects can also facilitate incremental recomputation and audit trails, enabling replayability and fault isolation.

Implementation considerations. A residobject can be implemented as a checkpoint-plus-log structure or as a conflict-free replicated data type (CRDT) style object to enable safe merging across replicas. Important design choices include storage overhead, the granularity of state capture, and guarantees about idempotence and determinism upon replay.

Limitations. The term residobject is not a widely standardized concept, and implementations vary. It adds complexity and storage requirements, and correctness depends on precise logging and clear semantics for merging and replay.

See also: checkpoints, snapshots, recovery logs, idempotence, CRDTs.