Realm
Operational Semantics
Correctness, delivery, persistence, recovery, consistency, coordination, and reliability.
Entries
ACID
ACID is a transaction contract: atomicity, consistency, isolation, and durability.
Acknowledgments
Acknowledgments answer: what does a participant or substrate claim has happened?
CAP Theorem
The CAP theorem describes an impossibility for distributed shared data under network partition: a system cannot simultaneously guarantee linearizable consistency, availability, and partition tolerance for all executions.
Commit Boundaries
Commit Boundaries answer: what becomes accepted as one unit, and within which boundary?
Concurrency Control
Concurrency Control answers: How can multiple concurrent histories be reconciled into a single valid history?
Consensus
Consensus answers: how do multiple observers agree on one decision, value, or ordered position despite concurrency, delay, partial failure, or independent local views?
Consistency Models
Consistency Models constrain which observations are valid for a set of events, transitions, versions, sessions, replicas, and ordering relations.
Coordination
Coordination answers: how is multi-step or multi-participant work made coherent across observers?
CRDTs
CRDTs, conflict-free replicated data types, are replicated data types designed so that independently updated replicas converge without requiring synchronous coordination for every update.
Delivery Semantics
Delivery Semantics answers: what guarantees does an interaction edge provide?
Dual-Write Problem
The dual-write problem is the failure mode that appears when one operation tries to commit two or more effects across independent commit boundaries without one atomic commit protocol or durable recovery protocol connecting them.
Durable Execution
Durable Execution is the operational semantics by which a process can continue coherently across failure, restart, suspension, timeout, or delayed external work.
Idempotency
Idempotency is the property that repeated handling of the same semantic input does not produce duplicate domain effects.
Interaction
Interaction answers: how do observers address, observe, notify, or invoke one another?
Isolation
Isolation describes what concurrent operations are allowed to observe of one another while they execute.
Ordering
Ordering defines the scope within which events, commands, observations, or effects are sequenced.
Persistence
Persistence answers: what is made durable and authoritative?
Progress Conditions
Progress Conditions classify liveness guarantees for concurrent or distributed operations.
Rate Limiting
Rate Limiting constrains how quickly work may be accepted, dispatched, delivered, or processed.
Reconstitution
Reconstitution answers: how is usable state recovered?
Recovery
Recovery defines how a system returns to coherent operation after failure, interruption, conflict, timeout, overload, or partial progress.
Retry
Retry is the controlled repetition of an operation after a transient failure, timeout, conflict, or unavailable dependency.
Safety and Liveness
Safety and Liveness separate two kinds of operational property of a distributed system.
Two-Phase Commit
Two-Phase Commit is a coordination protocol for atomic commit across multiple participants.
Version Histories
Version Histories describe the shape of state evolution for a subject, entity, document, repository, projection, or replicated object.
Weak Isolation Patterns
Weak Isolation Patterns are design techniques used when one ACID transaction or two-phase commit boundary is unavailable, too expensive, or not aligned with the business process.