fd4b6836ae
POST /vectors/lance/recall/{index} runs an existing harness through
Lance IVF_PQ search and measures recall@k against brute-force ground
truth. Uses the same EvalSet + ground_truth infrastructure as the
HNSW trial system — no new harness format needed.
First real measurement on resumes_100k_v2 (100K × 768d, 20 queries):
IVF_PQ (316 partitions, 8 bits, 48 subvectors): recall@10 = 0.805
For comparison — HNSW ec=80 es=30: recall@10 = 1.000
ADR-019 predicted "likely 0.85-0.95" — actual is 0.805. Slightly
below, but now the harness exists to iterate: increase partitions,
try ivf_hnsw_pq, tune subvectors. The measurement infrastructure
is the deliverable, not any specific recall target.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>