lancedb-gatefixer[bot]
2c06a48bd8
## Summary - add deterministic regression coverage that `Table.add()` releases backing Arrow buffers without cyclic garbage collection - track the foreign buffer owner rather than RSS, separating live input retention from allocator high-water behavior - preserve the bounded-lifetime behavior of the Scannable writer that superseded the historical preprocessing path ## Root cause The historical Python preprocessing/write path produced a high allocator RSS while ingesting very wide IPC batches. The current Scannable writer releases each input buffer when `Table.add()` completes; remaining RSS is allocator high-water rather than a live Arrow reference. The resolved behavior had no regression coverage, so a future native lifetime regression could silently reintroduce the original failure mode. ## Validation - `uv run --extra tests --extra dev maturin develop` - `uv run --project python --extra tests pytest python/python/tests/test_table.py::test_add python/python/tests/test_table.py::test_add_releases_arrow_buffers_without_gc -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 #2512 <!-- lance-gatekeeper-fix:v1 agent=29226408a8d07da592daf341d5384e37 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.