pgvector 0.8.7: hnsw.ef_search against the filtered query (category == 'c3' && year >= 2022); the filter is applied AFTER the index scan
ef_search  iterative_scan  mean hits    p50 ms  filt recall
40         off                   1.8       1.2        0.167
200        off                   2.0       1.7        0.198
1000       off                  10.0      28.2        1.000
40         relaxed_order        10.0       7.7        0.611
40         strict_order         10.0       9.7        0.281