713be8b50e
All 151 tests pass with 91.80% line coverage. All Definition of Done requirements verified. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
90 lines
4.3 KiB
Markdown
90 lines
4.3 KiB
Markdown
# Phase 1 — Core Routing Final Verification (2026-05-09)
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Bead ID: miroir-cdo
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Date: 2026-05-09
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## Summary
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Phase 1 Core Routing implementation verified as complete. All 151 tests pass with 91.80% line coverage, exceeding the 90% requirement.
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## Verification Results
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### Test Execution
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```
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running 151 tests
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test result: ok. 151 passed; 0 failed; 0 ignored; finished in 70.70s
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```
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### Coverage (cargo-llvm-cov)
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```
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Filename Regions Missed Regions Cover Functions Missed Functions Executed Lines Missed Lines Cover
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-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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router.rs 1016 26 97.44% 60 1 98.33% 500 19 96.20%
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topology.rs 776 0 100.00% 70 0 100.00% 421 0 100.00%
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scatter.rs 214 0 100.00% 11 0 100.00% 121 0 100.00%
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merger.rs 977 31 96.83% 49 4 91.84% 582 31 94.67%
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-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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TOTAL 5672 423 92.54% 396 33 91.67% 3770 309 91.80%
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```
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## Definition of Done Compliance
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| Requirement | Status | Test |
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|------------|--------|------|
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| Rendezvous assignment is deterministic | ✅ | `test_rendezvous_determinism`, `acceptance_determinism_1000_runs` |
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| Adding 4th node moves ≤ 2×(1/4) of shards | ✅ | `test_minimal_reshuffling_on_add`, `acceptance_reshuffle_bound_on_add` |
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| 64 shards / 3 nodes / RF=1 → 18-26 shards each | ✅ | `test_shard_distribution_64_3_rf1`, `acceptance_uniformity_64_shards_3_nodes_rf1` |
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| Top-RF placement changes minimally | ✅ | `test_top_rf_stability`, `acceptance_rf2_placement_stability` |
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| `write_targets` returns RG × RF nodes | ✅ | `test_write_targets_count` |
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| `query_group` distributes evenly | ✅ | `test_query_group_distribution` |
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| `covering_set` returns one node per shard | ✅ | `test_covering_set_one_per_shard`, `test_covering_set_replica_rotation` |
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| Merger passes merge/facet/limit tests | ✅ | 19 comprehensive merger tests |
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| miroir-core ≥ 90% line coverage | ✅ | **91.80%** |
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## Implementation Summary
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### router.rs
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- `score(shard_id, node_id)`: Rendezvous hashing with XxHash64::with_seed(0)
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- `assign_shard_in_group()`: Deterministic shard assignment within a group
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- `write_targets()`: Returns RG × RF nodes for writes
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- `query_group()`: Round-robin group selection for queries
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- `covering_set()`: One node per shard within chosen group
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- `shard_for_key()`: Key-to-shard mapping
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### topology.rs
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- `Topology`: Cluster topology with nodes grouped by replica_group
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- `NodeStatus`: Health state machine (Healthy/Active/Degraded/Joining/Draining/Failed/Removed)
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- `Group`: Replica group with node list
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- `NodeId`: Unique node identifier
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### scatter.rs
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- `Scatter` trait: Fan-out orchestration interface
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- `StubScatter`: Stub implementation (wired in Phase 2)
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### merger.rs
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- `merge()`: Global sort by _rankingScore, offset/limit, facet aggregation
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- `_rankingScore` stripping when not requested
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- `_miroir_*` fields always stripped
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- Binary heap optimization for large fan-out
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- BTreeMap for stable facet serialization
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## Retrospective
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### What worked
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- All core routing primitives implemented correctly
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- Comprehensive test coverage with deterministic tests
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- Rendezvous hashing provides minimal reshuffling on topology changes
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- Group-scoped assignment ensures replica isolation
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- Pure-function design enables thorough unit testing
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### What didn't
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- No issues encountered during verification
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### Surprise
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- Coverage exceeded 90% requirement without additional work
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### Reusable pattern
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- Rendezvous hashing with XxHash64::with_seed(0) for deterministic assignment
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- Group-scoped assignment for replica isolation
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- Pure-function design for testability
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- Node health state machine for cluster management
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