lancedb-gatefixer[bot]
4048150fdd
## Summary - add regression coverage for adding dictionary rows with a nullable fixed-size-list column - verify ordinary list columns remain aligned alongside the null fixed-size-list value ## Root cause PyArrow infers an all-`None` dictionary column as the generic `null` type. The original schema-alignment path treated the target fixed-size-list type as proof that the inferred source was also list-like and unconditionally accessed `value_field`, which raised `AttributeError`. Current alignment logic correctly falls back to the target type when the source is not list-like; this test locks in that repair for the reported ingestion path. ## Validation - `uv run --extra tests pytest python/tests/test_table.py::test_add_with_empty_fixed_size_list_drops_bad_rows python/tests/test_table.py::test_add_nullable_fixed_size_list_with_none python/tests/test_table.py::test_add_nullable_struct_with_none -q` - `uv run --with pyarrow==19.0.1 --extra tests pytest python/tests/test_table.py::test_add_nullable_fixed_size_list_with_none -q` - `uv run --project python --extra dev ruff format --check python/python/tests/test_table.py` - `uv run --project python --extra dev ruff check .` Fixes #2340 <!-- lance-gatekeeper-fix:v1 agent=cb0475e85e764f79bd03b35eb8955ec4 generation=1 --> Co-authored-by: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
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.