jedarden
c7be4ccbec
P12.OP4.1: Validate dfs_query_then_fetch benchmark (τ=0.9817) and document latency
Re-ran the 10K-query score-comparability benchmark with fresh results:
- DFS (global IDF preflight): avg τ = 0.9817, min τ = 0.9523, 0 queries below 0.95 → PASS
- Score merge (local IDF): avg τ = 0.7938, 62.9% queries below 0.95 → FAIL
- RRF merge: avg τ = 0.1361, 100% queries below 0.95 → CATASTROPHIC
Added Criterion latency benchmarks to the research doc:
- Global IDF aggregation: 285ns (3 shards) → 3.31µs (50 shards)
- Query term extraction: 69ns (1 word) → 726ns (9 words)
- IDF computation: ~113ps per term (trivial)
- Coordinator-side overhead is sub-microsecond; dominant cost is network round-trip
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>