6cf50fec1f
All Definition of Done requirements verified: - Rendezvous assignment determinism: ✓ - Minimal reshuffling on node add/remove: ✓ - Uniform shard distribution (64/3/RF=1): ✓ - Top-RF placement stability: ✓ - write_targets returns RG × RF nodes: ✓ - query_group distributes evenly: ✓ - covering_set returns one node per shard: ✓ - Merger passes merge/facet/limit tests: ✓ - Line coverage ≥ 90%: ✓ (91.80% overall, Phase 1 modules > 94%) Coverage breakdown: - router.rs: 96.20% - topology.rs: 100.00% - scatter.rs: 100.00% - merger.rs: 94.67% Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
3.6 KiB
3.6 KiB
Phase 1 — Core Routing Final Verification
Bead ID: miroir-cdo Date: 2026-05-09
Summary
Phase 1 Core Routing implementation complete and verified. All 151 tests pass, covering deterministic, coordination-free routing primitives that everything else depends on.
Verification Session (2026-05-09)
What Worked
- All core routing primitives (router.rs, topology.rs, scatter.rs, merger.rs) verified as complete
- All 151 tests pass (18 router tests, 19 merger tests, 29 topology tests, 6 scatter tests, plus other modules)
- Rendezvous hashing (HRW) with XxHash64::with_seed(0) provides deterministic, minimal-reshuffling shard assignment
- Group-scoped assignment prevents both replicas of a shard from landing in the same group
- Node health state machine fully implemented with all required states
- Merger handles all edge cases: empty shards, degraded mode, pagination, facets
What Didn't
- No issues encountered; the implementation was already complete and correct
Surprise
- cargo-llvm-cov was available and showed 91.80% line coverage, exceeding the 90% requirement
- Phase 1 modules specifically have excellent coverage: router.rs (96.20%), topology.rs (100%), scatter.rs (100%), merger.rs (94.67%)
Reusable Pattern
- Rendezvous hashing with XxHash64::with_seed(0) for deterministic shard assignment (matches Meilisearch Enterprise)
- Group-scoped assignment to ensure replica isolation
- Pure-function design for merger enables comprehensive unit testing without mocks
- Node health state machine: Healthy/Active (serving), Degraded (intermittent), Joining/Draining (transitional), Failed/Removed (unavailable)
- BTreeMap for stable JSON serialization in facet aggregation
DoD Status
| Requirement | Status |
|---|---|
| Rendezvous assignment is deterministic | ✅ Verified |
| Adding 4th node moves ≤ 2×(1/4) of shards | ✅ Verified |
| 64 shards / 3 nodes / RF=1 → 18-26 shards each | ✅ Verified |
| Top-RF placement changes minimally | ✅ Verified |
write_targets returns RG × RF nodes |
✅ Verified |
query_group distributes evenly |
✅ Verified |
covering_set returns one node per shard |
✅ Verified |
| Merger passes merge/facet/limit tests | ✅ Verified |
| miroir-core ≥ 90% line coverage | ✅ 91.80% (via cargo-llvm-cov) |
Coverage Report (cargo-llvm-cov)
Filename Regions Missed Regions Cover Functions Missed Functions Executed Lines Missed Lines Cover
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
router.rs 1016 26 97.44% 60 1 98.33% 500 19 96.20%
topology.rs 776 0 100.00% 70 0 100.00% 421 0 100.00%
scatter.rs 214 0 100.00% 11 0 100.00% 121 0 100.00%
merger.rs 977 31 96.83% 49 4 91.84% 582 31 94.67%
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL 5672 423 92.54% 396 33 91.67% 3770 309 91.80%
Test Results
running 151 tests
test result: ok. 151 passed; 0 failed; 0 ignored; finished in 106.38s