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PHASE 5 — READINESS & FREEZE

Status

  • Phase: 5
  • Authority: Normative (Closure Document)
  • Scope: Replication implementation readiness and freeze
  • Depends on:
  • OBSERVABILITY_VISION.md
  • OBSERVABILITY_INVARIANTS.md
  • OBSERVABILITY_IMPLEMENTATION_ORDER.md
  • REPLICATION_RUNTIME_ARCHITECTURE.md
  • OBSERVABILITY_FAILURE_MATRIX.md
  • OBSERVABILITY_TESTING_STRATEGY.md
  • OBSERVABILITY_OBSERVABILITY_MAPPING.md
  • All REPL_*, MVCC_*, and CORE_* documents

This document formally declares whether Phase 5 is complete, correct, and frozen.

1. Purpose

Phase 5 is the point where AeroDB becomes actually replicated, not just designed to be.

This document exists to:

  • Prevent “almost done” replication
  • Prevent silent semantic drift after implementation
  • Provide a hard correctness boundary
  • Declare replication semantics implemented and frozen

No new replication behavior may be introduced after this document is accepted.

2. Readiness Definition

Phase 5 is considered READY only if:

  • All replication semantics from Phase 2B are implemented
  • No Phase 2B or Phase 3 invariants are weakened
  • Phase 4 observability fully covers replication
  • All failure modes are tested and explained
  • Replication behavior is deterministic and auditable

Readiness is binary. There is no “mostly ready”.

3. Mandatory Completion Checklist

All items below MUST be satisfied.

3.1 Implementation Completeness

  • Primary / Replica role enforcement implemented
  • WAL shipping implemented (prefix rule enforced)
  • WAL validation implemented (checksum + continuity)
  • WAL application implemented (crash-safe)
  • Snapshot bootstrap implemented
  • Replica recovery implemented
  • Replica read-safety gate implemented
  • Replication disablement path verified

3.2 Invariant Compliance

  • All OBSERVABILITY_INVARIANTS.md invariants enforced
  • All REPL_INVARIANTS.md invariants enforced
  • No temporary invariant violations exist
  • No heuristic or timing-based logic introduced

3.3 Failure Coverage

  • All scenarios in OBSERVABILITY_FAILURE_MATRIX.md tested
  • Crash injection verified for:
  • WAL receive
  • WAL validation
  • WAL apply
  • Snapshot bootstrap
  • Replica recovery
  • No silent failure paths exist

3.4 Testing Coverage

  • All tests in OBSERVABILITY_TESTING_STRATEGY.md implemented
  • Crash tests deterministic
  • No skipped or ignored tests
  • Phase 0–4 tests unchanged and still passing

3.5 Observability & Explainability

  • /v1/replication fully implemented
  • Replication states observable
  • Blocking reasons explicit
  • /v1/explain/replication correct and evidence-based
  • Replica recovery explainable
  • Read-safety decisions explainable

3.6 Determinism & Replay

  • Replica restart produces identical state
  • WAL replay deterministic
  • Snapshot + WAL continuity verified
  • Observability output deterministic

4. Explicit Non-Readiness Conditions

Phase 5 MUST be considered NOT READY if any of the following are true:

  • Replica serves reads without proof
  • WAL prefix rule is violated even transiently
  • Validation and application overlap incorrectly
  • Failure states auto-clear without explanation
  • Any replication behavior depends on timing
  • Any invariant is “usually” but not always true

If any apply, Phase 5 cannot be frozen.

5. Freeze Declaration

Once all checklist items are satisfied, the following show be declared:

Phase 5 Replication Implementation is COMPLETE and FROZEN.

After freeze:

  • Replication semantics MUST NOT change
  • New replication features require Phase 6
  • Any bug fix must preserve semantics
  • Any deviation requires a new audit

6. Post-Freeze Guarantees

After Phase 5 freeze:

  • AeroDB supports correct, deterministic replication
  • Replication behavior is observable and explainable
  • Replica reads are safe or explicitly refused
  • Failures are loud and diagnosable

Availability is still secondary. Correctness is absolute.

7. Forward Boundary

After Phase 5, the next allowed phases are:

  • Phase 6: Failover & Promotion
  • Phase 6: Security & Hardening
  • Phase 6: Operational Tooling

None of these may begin until Phase 5 is frozen.

8. Final Rule

Replication that cannot be frozen
is replication that cannot be trusted.

This document exists to draw the line.

END OF DOCUMENT