Files
lancedb-gatefixer[bot] 1c3cd1d918 fix(python): accept Arrow scalars in table updates (#3838)
## Summary
- convert PyArrow scalar values through their Python representation
before SQL literal rendering
- add an end-to-end regression for updating a fixed-size-list vector
from a queried FixedSizeListScalar

## Root cause
Python update literal conversion used single dispatch for native Python
and NumPy values but had no PyArrow Scalar registration. A
FixedSizeListScalar returned by a query therefore reached the
unsupported generic conversion instead of the existing recursive list
converter.

## Validation
- uv run --extra tests pytest python/tests/test_table.py::test_update
python/tests/test_table.py::test_update_with_arrow_scalar
python/tests/test_table.py::test_update_types -q
- uv run --extra tests pytest python/tests/test_util.py -q
- uv run --project python --extra tests --extra dev ruff format --check
python/python/lancedb/util.py python/python/tests/test_table.py
- uv run --project python --extra tests --extra dev ruff check .

Fixes #1228

<!-- lance-gatekeeper-fix:v1 agent=950dd892194e53b61c203d5e3715cac7
generation=1 -->

Co-authored-by: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
2026-08-06 16:54:04 +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.