Add ANN search support for vec0 virtual table (#273)

Add approximate nearest neighbor infrastructure to vec0: shared distance
dispatch (vec0_distance_full), flat index type with parser, NEON-optimized
cosine/Hamming for float32/int8, amalgamation script, and benchmark suite
(benchmarks-ann/) with ground-truth generation and profiling tools. Remove
unused vec_npy_each/vec_static_blobs code, fix missing stdint.h include.
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Alex Garcia 2026-03-31 01:03:32 -07:00 committed by GitHub
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27 changed files with 2177 additions and 2116 deletions

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benchmarks-ann/bench.py Normal file
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#!/usr/bin/env python3
"""Benchmark runner for sqlite-vec KNN configurations.
Measures insert time, build/train time, DB size, KNN latency, and recall
across different vec0 configurations.
Config format: name:type=<index_type>,key=val,key=val
Baseline (brute-force) keys:
type=baseline, variant=float|int8|bit, oversample=8
Index-specific types can be registered via INDEX_REGISTRY (see below).
Usage:
python bench.py --subset-size 10000 \
"brute-float:type=baseline,variant=float" \
"brute-int8:type=baseline,variant=int8" \
"brute-bit:type=baseline,variant=bit"
"""
import argparse
import os
import sqlite3
import statistics
import time
_SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
EXT_PATH = os.path.join(_SCRIPT_DIR, "..", "dist", "vec0")
BASE_DB = os.path.join(_SCRIPT_DIR, "seed", "base.db")
INSERT_BATCH_SIZE = 1000
# ============================================================================
# Index registry — extension point for ANN index branches
# ============================================================================
#
# Each index type provides a dict with:
# "defaults": dict of default params
# "create_table_sql": fn(params) -> SQL string
# "insert_sql": fn(params) -> SQL string (or None for default)
# "post_insert_hook": fn(conn, params) -> train_time_s (or None)
# "run_query": fn(conn, params, query, k) -> [(id, distance), ...] (or None for default MATCH)
# "describe": fn(params) -> str (one-line description)
#
# To add a new index type, add an entry here. Example (in your branch):
#
# INDEX_REGISTRY["diskann"] = {
# "defaults": {"R": 72, "L": 128, "quantizer": "binary", "buffer_threshold": 0},
# "create_table_sql": lambda p: f"CREATE VIRTUAL TABLE vec_items USING vec0(...)",
# "insert_sql": None,
# "post_insert_hook": None,
# "run_query": None,
# "describe": lambda p: f"diskann q={p['quantizer']} R={p['R']} L={p['L']}",
# }
INDEX_REGISTRY = {}
# ============================================================================
# Baseline implementation
# ============================================================================
def _baseline_create_table_sql(params):
variant = params["variant"]
extra = ""
if variant == "int8":
extra = ", embedding_int8 int8[768]"
elif variant == "bit":
extra = ", embedding_bq bit[768]"
return (
f"CREATE VIRTUAL TABLE vec_items USING vec0("
f" chunk_size=256,"
f" id integer primary key,"
f" embedding float[768] distance_metric=cosine"
f" {extra})"
)
def _baseline_insert_sql(params):
variant = params["variant"]
if variant == "int8":
return (
"INSERT INTO vec_items(id, embedding, embedding_int8) "
"SELECT id, vector, vec_quantize_int8(vector, 'unit') "
"FROM base.train WHERE id >= :lo AND id < :hi"
)
elif variant == "bit":
return (
"INSERT INTO vec_items(id, embedding, embedding_bq) "
"SELECT id, vector, vec_quantize_binary(vector) "
"FROM base.train WHERE id >= :lo AND id < :hi"
)
return None # use default
def _baseline_run_query(conn, params, query, k):
variant = params["variant"]
oversample = params.get("oversample", 8)
if variant == "int8":
return conn.execute(
"WITH coarse AS ("
" SELECT id, embedding FROM vec_items"
" WHERE embedding_int8 MATCH vec_quantize_int8(:query, 'unit')"
" LIMIT :oversample_k"
") "
"SELECT id, vec_distance_cosine(embedding, :query) as distance "
"FROM coarse ORDER BY 2 LIMIT :k",
{"query": query, "k": k, "oversample_k": k * oversample},
).fetchall()
elif variant == "bit":
return conn.execute(
"WITH coarse AS ("
" SELECT id, embedding FROM vec_items"
" WHERE embedding_bq MATCH vec_quantize_binary(:query)"
" LIMIT :oversample_k"
") "
"SELECT id, vec_distance_cosine(embedding, :query) as distance "
"FROM coarse ORDER BY 2 LIMIT :k",
{"query": query, "k": k, "oversample_k": k * oversample},
).fetchall()
return None # use default MATCH
def _baseline_describe(params):
v = params["variant"]
if v in ("int8", "bit"):
return f"baseline {v} (os={params['oversample']})"
return f"baseline {v}"
INDEX_REGISTRY["baseline"] = {
"defaults": {"variant": "float", "oversample": 8},
"create_table_sql": _baseline_create_table_sql,
"insert_sql": _baseline_insert_sql,
"post_insert_hook": None,
"run_query": _baseline_run_query,
"describe": _baseline_describe,
}
# ============================================================================
# Config parsing
# ============================================================================
INT_KEYS = {
"R", "L", "buffer_threshold", "nlist", "nprobe", "oversample",
"n_trees", "search_k",
}
def parse_config(spec):
"""Parse 'name:type=baseline,key=val,...' into (name, params_dict)."""
if ":" in spec:
name, opts_str = spec.split(":", 1)
else:
name, opts_str = spec, ""
raw = {}
if opts_str:
for kv in opts_str.split(","):
k, v = kv.split("=", 1)
raw[k.strip()] = v.strip()
index_type = raw.pop("type", "baseline")
if index_type not in INDEX_REGISTRY:
raise ValueError(
f"Unknown index type: {index_type}. "
f"Available: {', '.join(sorted(INDEX_REGISTRY.keys()))}"
)
reg = INDEX_REGISTRY[index_type]
params = dict(reg["defaults"])
for k, v in raw.items():
if k in INT_KEYS:
params[k] = int(v)
else:
params[k] = v
params["index_type"] = index_type
return name, params
# ============================================================================
# Shared helpers
# ============================================================================
def load_query_vectors(base_db_path, n):
conn = sqlite3.connect(base_db_path)
rows = conn.execute(
"SELECT id, vector FROM query_vectors ORDER BY id LIMIT :n", {"n": n}
).fetchall()
conn.close()
return [(r[0], r[1]) for r in rows]
def insert_loop(conn, sql, subset_size, label=""):
t0 = time.perf_counter()
for lo in range(0, subset_size, INSERT_BATCH_SIZE):
hi = min(lo + INSERT_BATCH_SIZE, subset_size)
conn.execute(sql, {"lo": lo, "hi": hi})
conn.commit()
done = hi
if done % 5000 == 0 or done == subset_size:
elapsed = time.perf_counter() - t0
rate = done / elapsed if elapsed > 0 else 0
print(
f" [{label}] {done:>8}/{subset_size} "
f"{elapsed:.1f}s {rate:.0f} rows/s",
flush=True,
)
return time.perf_counter() - t0
def open_bench_db(db_path, ext_path, base_db):
if os.path.exists(db_path):
os.remove(db_path)
conn = sqlite3.connect(db_path)
conn.enable_load_extension(True)
conn.load_extension(ext_path)
conn.execute("PRAGMA page_size=8192")
conn.execute(f"ATTACH DATABASE '{base_db}' AS base")
return conn
DEFAULT_INSERT_SQL = (
"INSERT INTO vec_items(id, embedding) "
"SELECT id, vector FROM base.train WHERE id >= :lo AND id < :hi"
)
# ============================================================================
# Build
# ============================================================================
def build_index(base_db, ext_path, name, params, subset_size, out_dir):
db_path = os.path.join(out_dir, f"{name}.{subset_size}.db")
conn = open_bench_db(db_path, ext_path, base_db)
reg = INDEX_REGISTRY[params["index_type"]]
conn.execute(reg["create_table_sql"](params))
label = params["index_type"]
print(f" Inserting {subset_size} vectors...")
sql_fn = reg.get("insert_sql")
sql = sql_fn(params) if sql_fn else None
if sql is None:
sql = DEFAULT_INSERT_SQL
insert_time = insert_loop(conn, sql, subset_size, label)
train_time = 0.0
hook = reg.get("post_insert_hook")
if hook:
train_time = hook(conn, params)
row_count = conn.execute("SELECT count(*) FROM vec_items").fetchone()[0]
conn.close()
file_size_mb = os.path.getsize(db_path) / (1024 * 1024)
return {
"db_path": db_path,
"insert_time_s": round(insert_time, 3),
"train_time_s": round(train_time, 3),
"total_time_s": round(insert_time + train_time, 3),
"insert_per_vec_ms": round((insert_time / row_count) * 1000, 2)
if row_count
else 0,
"rows": row_count,
"file_size_mb": round(file_size_mb, 2),
}
# ============================================================================
# KNN measurement
# ============================================================================
def _default_match_query(conn, query, k):
return conn.execute(
"SELECT id, distance FROM vec_items "
"WHERE embedding MATCH :query AND k = :k",
{"query": query, "k": k},
).fetchall()
def measure_knn(db_path, ext_path, base_db, params, subset_size, k=10, n=50):
conn = sqlite3.connect(db_path)
conn.enable_load_extension(True)
conn.load_extension(ext_path)
conn.execute(f"ATTACH DATABASE '{base_db}' AS base")
query_vectors = load_query_vectors(base_db, n)
reg = INDEX_REGISTRY[params["index_type"]]
query_fn = reg.get("run_query")
times_ms = []
recalls = []
for qid, query in query_vectors:
t0 = time.perf_counter()
results = None
if query_fn:
results = query_fn(conn, params, query, k)
if results is None:
results = _default_match_query(conn, query, k)
elapsed_ms = (time.perf_counter() - t0) * 1000
times_ms.append(elapsed_ms)
result_ids = set(r[0] for r in results)
# Ground truth: use pre-computed neighbors table for full dataset,
# otherwise brute-force over the subset
if subset_size >= 1000000:
gt_rows = conn.execute(
"SELECT CAST(neighbors_id AS INTEGER) FROM base.neighbors "
"WHERE query_vector_id = :qid AND rank < :k",
{"qid": qid, "k": k},
).fetchall()
else:
gt_rows = conn.execute(
"SELECT id FROM ("
" SELECT id, vec_distance_cosine(vector, :query) as dist "
" FROM base.train WHERE id < :n ORDER BY dist LIMIT :k"
")",
{"query": query, "k": k, "n": subset_size},
).fetchall()
gt_ids = set(r[0] for r in gt_rows)
if gt_ids:
recalls.append(len(result_ids & gt_ids) / len(gt_ids))
else:
recalls.append(0.0)
conn.close()
return {
"mean_ms": round(statistics.mean(times_ms), 2),
"median_ms": round(statistics.median(times_ms), 2),
"p99_ms": round(sorted(times_ms)[int(len(times_ms) * 0.99)], 2)
if len(times_ms) > 1
else round(times_ms[0], 2),
"total_ms": round(sum(times_ms), 2),
"recall": round(statistics.mean(recalls), 4),
}
# ============================================================================
# Results persistence
# ============================================================================
def save_results(results_path, rows):
db = sqlite3.connect(results_path)
db.executescript(open(os.path.join(_SCRIPT_DIR, "schema.sql")).read())
for r in rows:
db.execute(
"INSERT OR REPLACE INTO build_results "
"(config_name, index_type, subset_size, db_path, "
" insert_time_s, train_time_s, total_time_s, rows, file_size_mb) "
"VALUES (?,?,?,?,?,?,?,?,?)",
(
r["name"], r["index_type"], r["n_vectors"], r["db_path"],
r["insert_time_s"], r["train_time_s"], r["total_time_s"],
r["rows"], r["file_size_mb"],
),
)
db.execute(
"INSERT OR REPLACE INTO bench_results "
"(config_name, index_type, subset_size, k, n, "
" mean_ms, median_ms, p99_ms, total_ms, qps, recall, db_path) "
"VALUES (?,?,?,?,?,?,?,?,?,?,?,?)",
(
r["name"], r["index_type"], r["n_vectors"], r["k"], r["n_queries"],
r["mean_ms"], r["median_ms"], r["p99_ms"], r["total_ms"],
round(r["n_queries"] / (r["total_ms"] / 1000), 1)
if r["total_ms"] > 0 else 0,
r["recall"], r["db_path"],
),
)
db.commit()
db.close()
# ============================================================================
# Reporting
# ============================================================================
def print_report(all_results):
print(
f"\n{'name':>20} {'N':>7} {'type':>10} {'config':>28} "
f"{'ins(s)':>7} {'train':>6} {'MB':>7} "
f"{'qry(ms)':>8} {'recall':>7}"
)
print("-" * 115)
for r in all_results:
train = f"{r['train_time_s']:.1f}" if r["train_time_s"] > 0 else "-"
print(
f"{r['name']:>20} {r['n_vectors']:>7} {r['index_type']:>10} "
f"{r['config_desc']:>28} "
f"{r['insert_time_s']:>7.1f} {train:>6} {r['file_size_mb']:>7.1f} "
f"{r['mean_ms']:>8.2f} {r['recall']:>7.4f}"
)
# ============================================================================
# Main
# ============================================================================
def main():
parser = argparse.ArgumentParser(
description="Benchmark runner for sqlite-vec KNN configurations",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=__doc__,
)
parser.add_argument("configs", nargs="+", help="config specs (name:type=X,key=val,...)")
parser.add_argument("--subset-size", type=int, required=True)
parser.add_argument("-k", type=int, default=10, help="KNN k (default 10)")
parser.add_argument("-n", type=int, default=50, help="number of queries (default 50)")
parser.add_argument("--base-db", default=BASE_DB)
parser.add_argument("--ext", default=EXT_PATH)
parser.add_argument("-o", "--out-dir", default="runs")
parser.add_argument("--results-db", default=None,
help="path to results DB (default: <out-dir>/results.db)")
args = parser.parse_args()
os.makedirs(args.out_dir, exist_ok=True)
results_db = args.results_db or os.path.join(args.out_dir, "results.db")
configs = [parse_config(c) for c in args.configs]
all_results = []
for i, (name, params) in enumerate(configs, 1):
reg = INDEX_REGISTRY[params["index_type"]]
desc = reg["describe"](params)
print(f"\n[{i}/{len(configs)}] {name} ({desc.strip()})")
build = build_index(
args.base_db, args.ext, name, params, args.subset_size, args.out_dir
)
train_str = f" + {build['train_time_s']}s train" if build["train_time_s"] > 0 else ""
print(
f" Build: {build['insert_time_s']}s insert{train_str} "
f"{build['file_size_mb']} MB"
)
print(f" Measuring KNN (k={args.k}, n={args.n})...")
knn = measure_knn(
build["db_path"], args.ext, args.base_db,
params, args.subset_size, k=args.k, n=args.n,
)
print(f" KNN: mean={knn['mean_ms']}ms recall@{args.k}={knn['recall']}")
all_results.append({
"name": name,
"n_vectors": args.subset_size,
"index_type": params["index_type"],
"config_desc": desc,
"db_path": build["db_path"],
"insert_time_s": build["insert_time_s"],
"train_time_s": build["train_time_s"],
"total_time_s": build["total_time_s"],
"insert_per_vec_ms": build["insert_per_vec_ms"],
"rows": build["rows"],
"file_size_mb": build["file_size_mb"],
"k": args.k,
"n_queries": args.n,
"mean_ms": knn["mean_ms"],
"median_ms": knn["median_ms"],
"p99_ms": knn["p99_ms"],
"total_ms": knn["total_ms"],
"recall": knn["recall"],
})
print_report(all_results)
save_results(results_db, all_results)
print(f"\nResults saved to {results_db}")
if __name__ == "__main__":
main()