Terminology and Conventions

This document defines the terminology used throughout Primatomic documentation.

Service Guarantees

Primatomic provides the following guarantees:

Durability

• Events appended to a log are durably stored before the append response is returned.
• The service does not acknowledge an append until the event is persisted.

Log Ordering

• Events within a single log are assigned strictly monotonically increasing sequence numbers.
• Each event is stored exactly once with a unique sequence number.
• The service never reorders or skips events within a log.

View Processing

• Views process events in sequence order.
• View execution is at-least-once: events may be reprocessed after failures.
• Views are expected to be deterministic. Applying the same event sequence must produce the same state.

Consistency

• When a query specifies a sequence number, the response reflects all events up to and including that sequence.
• Queries without a sequence number may return stale results.

Isolation

• Tenants cannot access other tenants’ logs, views, or data.
• API keys only authorize access to the owning tenant’s resources.

Availability

• The service maintains high availability through distributed leadership election.
• View queries may be temporarily unavailable during leader transitions.

Definitions

Term	Definition
Tenant	An isolated account with its own logs, views, and API keys.
Log	An append-only sequence of events belonging to a tenant.
Event	A binary payload appended to a log, assigned a sequence number.
View	A WASM component that processes log events and maintains queryable state.
Sequence Number	A monotonically increasing identifier assigned to each event in a log.
Leader	The node responsible for processing events and serving queries for a view.
Snapshot	A serialized representation of view state used for recovery.
Stale Read	A query that may not reflect the most recent events.
Read-After-Write	A consistency model where reads reflect preceding writes.