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lancedb/python/python/tests/test_hybrid_query.py
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lancedb-gatefixer[bot] 173f889d2a test(python): cover stale scalar prefilters in hybrid search (#3865)
## Summary

- capture the stale-index state behind the reported fixed-size-binary
panic: the vector and FTS indices cover newer fragments while the BTree
prefilter does not
- verify vector, FTS, and hybrid searches return matches from both
scalar-indexed and unindexed fragments without panicking
- preserve binding-level coverage for the Lance fix in
https://github.com/lance-format/lance/pull/3768, which restricts
incomplete scalar prefilters when search indices are further ahead

The production root cause is in Lance and the current LanceDB dependency
already contains that fix, so this change adds the missing LanceDB
Python regression coverage.

## Validation

- `cd python && uv run --no-sync pytest
python/tests/test_hybrid_query.py::test_hybrid_query_with_stale_fixed_size_binary_prefilter
-q`
- `cd python && uv run --no-sync pytest
python/tests/test_hybrid_query.py -q`
- `python/.venv/bin/ruff check .`
- `python/.venv/bin/ruff format --check
python/python/tests/test_hybrid_query.py`

Fixes #2370

<!-- lance-gatekeeper-fix:v1 agent=5d16e59b9e513fd9247e0698732fa283
generation=1 -->

Co-authored-by: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
2026-08-06 16:44:20 +08:00

386 lines
12 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright The LanceDB Authors
from unittest import mock
import lancedb
from lancedb.query import LanceHybridQueryBuilder
from lancedb.rerankers.rrf import RRFReranker
import pyarrow as pa
import pyarrow.compute as pc
import pytest
import pytest_asyncio
from lancedb.index import BTree, FTS, IvfPq
from lancedb.table import AsyncTable, Table
@pytest.fixture
def sync_table(tmpdir_factory) -> Table:
tmp_path = str(tmpdir_factory.mktemp("data"))
db = lancedb.connect(tmp_path)
data = pa.table(
{
"text": pa.array(["a", "b", "cat", "dog"]),
"vector": pa.array(
[[0.1, 0.1], [2, 2], [-0.1, -0.1], [0.5, -0.5]],
type=pa.list_(pa.float32(), list_size=2),
),
}
)
table = db.create_table("test", data)
table.create_fts_index("text", with_position=False)
return table
@pytest_asyncio.fixture
async def table(tmpdir_factory) -> AsyncTable:
tmp_path = str(tmpdir_factory.mktemp("data"))
db = await lancedb.connect_async(tmp_path)
data = pa.table(
{
"text": pa.array(["a", "b", "cat", "dog"]),
"vector": pa.array(
[[0.1, 0.1], [2, 2], [-0.1, -0.1], [0.5, -0.5]],
type=pa.list_(pa.float32(), list_size=2),
),
}
)
table = await db.create_table("test", data)
await table.create_index("text", config=FTS(with_position=False))
return table
@pytest.mark.asyncio
async def test_async_hybrid_query(table: AsyncTable):
result = await (
table.query().nearest_to([0.0, 0.4]).nearest_to_text("dog").limit(2).to_arrow()
)
assert len(result) == 2
# ensure we get results that would match well for text and vector
assert result["text"].to_pylist() == ["a", "dog"]
# ensure there is no rowid by default
assert "_rowid" not in result
@pytest.mark.asyncio
async def test_async_hybrid_query_with_row_ids(table: AsyncTable):
result = await (
table.query()
.nearest_to([0.0, 0.4])
.nearest_to_text("dog")
.limit(2)
.with_row_id()
.to_arrow()
)
assert len(result) == 2
# ensure we get results that would match well for text and vector
assert result["text"].to_pylist() == ["a", "dog"]
assert result["_rowid"].to_pylist() == [0, 3]
@pytest.mark.asyncio
async def test_async_hybrid_query_filters(table: AsyncTable):
# test that query params are passed down from the regular builder to
# child vector/fts builders
result = await (
table.query()
.where("text not in ('a', 'dog')")
.nearest_to([0.3, 0.3])
.nearest_to_text("*a*")
.distance_type("l2")
.limit(2)
.to_arrow()
)
assert len(result) == 2
# ensure we get results that would match well for text and vector
assert result["text"].to_pylist() == ["cat", "b"]
@pytest.mark.asyncio
async def test_hybrid_query_with_stale_fixed_size_binary_prefilter(
tmpdir_factory,
):
tmp_path = str(tmpdir_factory.mktemp("stale_scalar_prefilter"))
db = await lancedb.connect_async(tmp_path)
def fixed_size_binary(value: int) -> bytes:
return value.to_bytes(16, byteorder="big")
num_rows = 1000
data = pa.table(
{
"space_id": pa.array(
[fixed_size_binary(i) for i in range(num_rows)],
type=pa.binary(16),
),
"text": ["book"] * num_rows,
"vector": pa.array(
[[float(i), float(i)] for i in range(num_rows)],
type=pa.list_(pa.float32(), 2),
),
}
)
table = await db.create_table("test", data)
await table.create_index(
"vector", config=IvfPq(num_partitions=4, num_sub_vectors=2)
)
await table.create_index("space_id", config=BTree())
await table.create_index("text", config=FTS(with_position=False))
# Advance the search indices without advancing the scalar index. This is the
# state that previously let hybrid search use an incomplete scalar prefilter.
await table.add(data)
lance_dataset = await table.to_lance()
lance_dataset.optimize.optimize_indices(index_names=["vector_idx", "text_idx"])
await table.checkout_latest()
scalar_stats = await table.index_stats("space_id_idx")
assert scalar_stats is not None
assert scalar_stats.num_indexed_rows == num_rows
assert scalar_stats.num_unindexed_rows == num_rows
for index_name in ["vector_idx", "text_idx"]:
search_stats = await table.index_stats(index_name)
assert search_stats is not None
assert search_stats.num_indexed_rows == num_rows * 2
assert search_stats.num_unindexed_rows == 0
matching_ids = [5, 10, 15, 20, 25, 30]
literals = [
f"arrow_cast(0x{fixed_size_binary(i).hex()}, 'FixedSizeBinary(16)')"
for i in matching_ids
]
predicate = f"space_id IN ({', '.join(literals)})"
expected_ids = sorted(fixed_size_binary(i) for i in matching_ids for _ in range(2))
vector_query = (
table.query().where(predicate).nearest_to([5.0, 5.0]).limit(num_rows * 2)
)
vector_results = await vector_query.to_arrow()
assert sorted(vector_results["space_id"].to_pylist()) == expected_ids
fts_query = (
table.query().where(predicate).nearest_to_text("book").limit(num_rows * 2)
)
fts_results = await fts_query.to_arrow()
assert sorted(fts_results["space_id"].to_pylist()) == expected_ids
hybrid_results = await (
table.query()
.where(predicate)
.nearest_to([5.0, 5.0])
.nearest_to_text("book")
.limit(num_rows * 2)
.to_arrow()
)
assert sorted(hybrid_results["space_id"].to_pylist()) == expected_ids
@pytest.mark.asyncio
async def test_async_hybrid_query_default_limit(table: AsyncTable):
# add 10 new rows
new_rows = []
for i in range(100):
if i < 2:
new_rows.append({"text": "close_vec", "vector": [0.1, 0.1]})
else:
new_rows.append({"text": "far_vec", "vector": [5 * i, 5 * i]})
await table.add(new_rows)
result = await (
table.query().nearest_to_text("dog").nearest_to([0.1, 0.1]).to_arrow()
)
# assert we got the default limit of 10
assert len(result) == 10
# assert we got the closest vectors and the text searched for
texts = result["text"].to_pylist()
assert texts.count("close_vec") == 2
assert texts.count("dog") == 1
assert texts.count("a") == 1
def test_hybrid_query_minimum_nprobes_zero_raises(sync_table: Table):
# minimum_nprobes(0) must raise the same validation error a plain vector
# query raises, not silently no-op because 0 is falsy.
with pytest.raises(ValueError, match="minimum_nprobes must be greater than 0"):
(
sync_table.search(query_type="hybrid")
.vector([0.0, 0.4])
.text("dog")
.minimum_nprobes(0)
.to_arrow()
)
def test_hybrid_query_distance_range(sync_table: Table):
reranker = RRFReranker(return_score="all")
result = (
sync_table.search(query_type="hybrid")
.vector([0.0, 0.4])
.text("cat and dog")
.distance_range(lower_bound=0.2, upper_bound=0.5)
.rerank(reranker)
.limit(2)
.to_arrow()
)
assert len(result) == 2
print(result)
for dist in result["_distance"]:
if dist.is_valid:
assert 0.2 <= dist.as_py() <= 0.5
def test_hybrid_query_applies_zero_upper_distance_bound(sync_table: Table):
result = (
sync_table.search(query_type="hybrid")
.vector([0.0, 0.4])
.text("elephant")
.distance_range(upper_bound=0.0)
.rerank(RRFReranker(return_score="all"))
.limit(4)
.to_arrow()
)
assert len(result) == 0
@pytest.mark.asyncio
async def test_hybrid_query_distance_range_async(table: AsyncTable):
reranker = RRFReranker(return_score="all")
result = await (
table.query()
.nearest_to([0.0, 0.4])
.nearest_to_text("cat and dog")
.distance_range(lower_bound=0.2, upper_bound=0.5)
.rerank(reranker)
.limit(2)
.to_arrow()
)
assert len(result) == 2
for dist in result["_distance"]:
if dist.is_valid:
assert 0.2 <= dist.as_py() <= 0.5
@pytest.mark.asyncio
async def test_explain_plan(table: AsyncTable):
plan = await (
table.query().nearest_to_text("dog").nearest_to([0.1, 0.1]).explain_plan(True)
)
assert "KNNVectorDistance" in plan
assert "LanceRead" in plan
@pytest.mark.asyncio
async def test_analyze_plan(table: AsyncTable):
res = await (
table.query().nearest_to_text("dog").nearest_to([0.1, 0.1]).analyze_plan()
)
assert "AnalyzeExec" in res
assert "metrics=" in res
def test_hybrid_phrase_query_is_preserved_in_analyze_plan():
table = mock.Mock()
analyzed_queries = []
distributed_metric_modes = []
def capture_query(query, *, distributed_metrics="aggregate"):
analyzed_queries.append(query)
distributed_metric_modes.append(distributed_metrics)
return ""
table._analyze_plan.side_effect = capture_query
(
LanceHybridQueryBuilder(table)
.vector([0.1, 0.2])
.text("puppy runs")
.phrase_query()
.analyze_plan(distributed_metrics="full")
)
assert len(analyzed_queries) == 2
assert analyzed_queries[1].full_text_query.query == '"puppy runs"'
assert distributed_metric_modes == ["full", "full"]
@pytest.fixture
def table_with_id(tmpdir_factory) -> Table:
tmp_path = str(tmpdir_factory.mktemp("data"))
db = lancedb.connect(tmp_path)
data = pa.table(
{
"id": pa.array([1, 2, 3, 4], type=pa.int64()),
"text": pa.array(["a", "b", "cat", "dog"]),
"vector": pa.array(
[[0.1, 0.1], [2, 2], [-0.1, -0.1], [0.5, -0.5]],
type=pa.list_(pa.float32(), list_size=2),
),
}
)
table = db.create_table("test_with_id", data)
table.create_fts_index("text", with_position=False)
return table
def test_hybrid_prefilter_explain_plan(table_with_id: Table):
"""
Verify that the prefilter logic is not inverted in LanceHybridQueryBuilder.
"""
plan_prefilter = (
table_with_id.search(query_type="hybrid")
.vector([0.0, 0.0])
.text("dog")
.where("id = 1", prefilter=True)
.limit(2)
.explain_plan(verbose=True)
)
plan_postfilter = (
table_with_id.search(query_type="hybrid")
.vector([0.0, 0.0])
.text("dog")
.where("id = 1", prefilter=False)
.limit(2)
.explain_plan(verbose=True)
)
# prefilter=True: filter is pushed into the LanceRead scan.
# The FTS sub-plan exposes this as "full_filter=id = Int64(1)" inside LanceRead.
assert "full_filter=id = Int64(1)" in plan_prefilter, (
f"Should push the filter into the scan.\nPlan:\n{plan_prefilter}"
)
# prefilter=False: filter is applied as a separate FilterExec after the search.
# The filter must NOT be embedded in the scan.
assert "full_filter=id = Int64(1)" not in plan_postfilter, (
f"Should NOT push the filter into the scan.\nPlan:\n{plan_postfilter}"
)
def test_normalize_scores():
cases = [
(pa.array([0.1, 0.4]), pa.array([0.0, 1.0])),
(pa.array([2.0, 10.0, 20.0]), pa.array([0.0, 8.0 / 18.0, 1.0])),
(pa.array([0.0, 0.0, 0.0]), pa.array([0.0, 0.0, 0.0])),
(pa.array([10.0, 9.9999999999999]), pa.array([0.0, 0.0])),
]
for input, expected in cases:
for invert in [True, False]:
result = LanceHybridQueryBuilder._normalize_scores(input, invert)
if invert:
expected = pc.subtract(1.0, expected)
assert pc.equal(result, expected), (
f"Expected {expected} but got {result} for invert={invert}"
)