Append-Only Log

Kind: pattern

Layer: Execution Core

Record: architecture:append-only-log

Severity: contextual

Scope: event store, audit, stream

Canonical: Ontology

A design pattern that records history as immutable entries added at the end of the log.

Listed in Architecture principles, after Compensating Transaction and before Dead-Letter Queue.

Requires

• Immutable Events

Reinforces

• Auditability
• Event Sourcing

Enables

• Replay
• Temporal Queries

Conflicts with

• In-Place Mutation

In tension with

• Storage Growth

Tensions

• Append-Only Log / Storage Growth

Violated by

• In-Place Mutation

Refactored by

• Snapshot Compaction

Severity

• contextual

Category

• Event / Messaging / Asynchronous Architecture

Refactors

• Audit Logging

Linked from

• Coordination is software
• The board and the venue
• Execution joins the halves
• Event / Messaging / Asynchronous Architecture
• Observability / Auditability / Traceability
• Core Vocabulary
• Event Messaging Async
• Severity levels
• The resolutions

in this codebase

• appendSection