diff --git a/notes/miroir-mkk.2.md b/notes/miroir-mkk.2.md new file mode 100644 index 0000000..34c0b07 --- /dev/null +++ b/notes/miroir-mkk.2.md @@ -0,0 +1,79 @@ +# P4.2 Node Addition: Dual-Write + Paginated Shard Migration - Verification + +## Summary + +Verified that the P4.2 node addition implementation is complete and fully functional. All acceptance criteria tests pass. + +## Implementation Verified + +### Core Components (Already Implemented) + +1. **`crates/miroir-core/src/rebalancer.rs`**: + - `add_node()` method creates node addition operation + - `compute_shard_moves_for_new_node()` determines affected shards + - `run_migration_task()` executes paginated migration with dual-write + - `HttpMigrationExecutor` implements actual HTTP-based document migration + - Delta pass support for catching stragglers + +2. **`crates/miroir-core/src/migration.rs`**: + - Complete migration state machine with all phases + - `MigrationCoordinator` for state transitions + - `begin_dual_write()` starts dual-write phase + - `begin_cutover()`, `complete_drain()`, `complete_cleanup()` for cutover sequence + - Safety validation (anti-entropy required if delta pass skipped) + +3. **`crates/miroir-core/src/rebalancer_worker/mod.rs`**: + - Background worker with leader lease + - `on_node_added()` handles topology events + - `drive_migrations()` advances migration state machine + - Job persistence via TaskStore + +4. **`crates/miroir-proxy/src/routes/admin_endpoints.rs`**: + - `add_node` API endpoint + - Integration with rebalancer worker via event channel + +### Integration Tests (All Pass) + +**`crates/miroir-core/tests/p42_node_addition.rs`**: +1. `p42_node_addition_3_to_4_migration_10k_docs` - 10K docs migration test +2. `p42_chaos_writes_during_migration_dual_write` - Dual-write chaos test +3. `p42_performance_document_count_bounds` - Performance bounds verification +4. `p42_log_inspection_old_node_not_queried_after_migration` - Log inspection test +5. `p42_verify_dual_write_during_migration` - Dual-write verification +6. `p42_pagination_limit_offset` - Pagination verification + +**`crates/miroir-core/tests/cutover_race.rs`**: +- 14 chaos tests for cutover boundary conditions +- All pass with anti-entropy and delta pass + +**`crates/miroir-core/tests/p4_topology_chaos.rs`**: +- 8 topology chaos tests +- All pass + +## Acceptance Criteria Status + +- [x] Integration test: 3-node → 4-node migration, 10K docs, each doc still retrievable by ID after migration +- [x] Chaos: toggle writes on/off during migration; dual-write window catches all late writes +- [x] Performance: migrating `~S/(Ng+1)` shards moves ≤ `total_docs / (Ng+1) × 1.1` docs (10% slack for dual-write dupes) +- [x] The old node is not queried for the migrated shards after step 8 (verified via log inspection) + +## Test Results + +``` +running 6 tests (p42_node_addition) +test p42_chaos_writes_during_migration_dual_write ... ok +test p42_node_addition_3_to_4_migration_10k_docs ... ok +test p42_log_inspection_old_node_not_queried_after_migration ... ok +test p42_performance_document_count_bounds ... ok +test p42_verify_dual_write_during_migration ... ok +test p42_pagination_limit_offset ... ok +test result: ok. 6 passed + +running 14 tests (cutover_race) +test result: ok. 14 passed + +running 8 tests (p4_topology_chaos) +test result: ok. 8 passed +``` + +Total: 28 tests passed, 0 failed.