Files
lancedb/python
lancedb-gatefixer[bot] c5f9efefe9 test(python): cover local sync multiple-vector search (#3830)
## Summary
- add regression coverage for multiple query vectors in the local
synchronous Python API
- verify that each query vector receives its own limited
nearest-neighbor result and `query_index`

## Root cause
In LanceDB v0.16, the local synchronous scanner passed a nested vector
array as one query, unlike the async and remote implementations. The
subsequent sync-to-async table migration supplied the correct shared
runtime path, but this local sync behavior was never regression-tested
and issue #1857 remained open.

## Validation
- `uv run --extra tests pytest
python/tests/test_query.py::test_query_multiple_vectors -q`
- `uv run --project python --extra tests --extra dev ruff format --check
python/python/tests/test_query.py`
- `uv run --project python --extra tests --extra dev ruff check .`

Fixes #1857

<!-- lance-gatekeeper-fix:v1 agent=6b25bc529d76813c3db7627c8be947ef
generation=1 -->

Co-authored-by: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
2026-08-07 17:30:55 +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.