Files
lancedb/python
Adityaj0 e6ae93f52a fix: hybrid search minimum_nprobes(0) silently no-ops instead of raising (#3770)
## Summary

`LanceHybridQueryBuilder._create_query_builders()` checked
`self._minimum_nprobes` for truthiness instead of `is not None` — the
very next line correctly checks `is not None` for
`self._maximum_nprobes`. Since `0` is falsy in Python,
`.minimum_nprobes(0)` on a hybrid query silently dropped the value
instead of forwarding it to the vector sub-query, where it would raise
the same `ValueError` a plain vector query raises for the same input
(`minimum_nprobes must be greater than 0`, validated in
`rust/lancedb/src/query.rs` and covered for the plain-query path by
`test_invalid_nprobes_sync`).

Fixes #3766

## Change

One-line fix: `if self._minimum_nprobes:` → `if self._minimum_nprobes is
not None:`, matching the existing `maximum_nprobes` check right below
it.

## Test plan

- [x] New regression test
`test_hybrid_query_minimum_nprobes_zero_raises` in
`python/python/tests/test_hybrid_query.py`
- [x] `uv run --extra tests pytest python/tests/test_hybrid_query.py
-vv` — 13 passed
- [x] `uv run --extra dev ruff format` / `ruff check` — clean

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-03 12:54:41 -07:00
..
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.