Files
lancedb/python
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
..
2025-01-29 08:27:07 -08:00
2024-04-05 16:22:59 -07:00

LanceDB Python SDK

A Python library for LanceDB.

Installation

pip install lancedb

Pre-Haswell x86_64 hosts: lancedb-compat

The default lancedb wheel targets x86-64-haswell (AVX2 + FMA + F16C) for full performance on modern hardware. Pre-Haswell hosts — Intel Sandy Bridge / Ivy Bridge / Westmere; AMD Bulldozer / Piledriver / Steamroller — don't have AVX2 and crash with Illegal instruction at import lancedb.

For those hosts, install the lancedb-compat package instead:

pip install lancedb-compat

Same Python API (import lancedb works as usual). The compat wheel is compiled at the x86-64-v2 baseline (Nehalem-class) and uses runtime SIMD dispatch in the embedded lance crate to pick the right kernel tier (scalar / AVX / AVX+FMA / AVX2+FMA / AVX-512) at load time, so it still goes fast on modern hardware while running cleanly on the pre-Haswell silicon. Use lance.simd_info() from Python to verify which tier was selected.

lancedb and lancedb-compat install to the same lancedb/ namespace and conflict at install time. Pick one. To switch, pip uninstall lancedb first, then pip install lancedb-compat (or vice-versa).

If you need a custom baseline (or lancedb-compat isn't yet published for your platform), build from source with the override:

RUSTFLAGS="-C target-cpu=x86-64-v2" maturin build --release
pip install ./target/wheels/lancedb-*.whl

Preview Releases

Stable releases are created about every 2 weeks. For the latest features and bug fixes, you can install the preview release. These releases receive the same level of testing as stable releases, but are not guaranteed to be available for more than 6 months after they are released. Once your application is stable, we recommend switching to stable releases.

pip install --pre --extra-index-url https://pypi.fury.io/lancedb/ lancedb

Usage

Basic Example

import lancedb
db = lancedb.connect('<PATH_TO_LANCEDB_DATASET>')
table = db.open_table('my_table')
results = table.search([0.1, 0.3]).limit(20).to_list()
print(results)

Development

See CONTRIBUTING.md for information on how to contribute to LanceDB.