PSTATE

pState is a term used in software engineering to denote persistent state, the portion of a program's state that remains durable across process lifetimes, crashes, and restarts. It contrasts with ephemeral, in-memory state that is lost when a system terminates.

In pState designs, durable storage is used to record the history of changes to the application's state. Changes are typically captured as events or as updates to a state machine, and the current state may be reconstructed by replaying events or applying snapshots.

Architectures that support pState commonly separate execution state from persisted state. A state store or event log serves as the canonical source of truth, while a state manager or reducer applies changes to derive the current view. Clients issue commands or events, which are appended to the log and then used to update the state store.

Common patterns include event sourcing, where state is the result of replayed events, and CQRS, which separates read and write models. Techniques such as snapshotting and compaction help manage large histories, and replication or partitioning addresses durability and availability in distributed systems.

Practical implementations depend on context and requirements; they may involve relational or NoSQL databases, distributed logs, or object stores. pState concepts underpin offline-first applications, fault-tolerant services, and long-running workflows where progress must be preserved across failures.

Limitations include added complexity, latency, versioning challenges, and the need for robust conflict resolution in distributed deployments.