lancedb-gatefixer[bot]
1e4662ac23
Remote SDKs report Cloud-specific errors against self-hosted servers, and some Python wrappers raise different exception types for the same unsupported operation. The sync index wrapper also warns that `replace` is ignored even though Rust forwards it to the server. Use backend-neutral table/server diagnostics and the existing `NotSupported` error conversions for unsupported manifest operations, blob ranges, primary keys, optimization, and HNSW-PQ indexes. Sync Python delegates to the async paths, so manifest operations and `optimize()` consistently raise `NotImplementedError`. Legacy and config-based HNSW-PQ creation share the same error and alternative-index advice. Remove the false replacement warning and simplify the ignored GPU-accelerator warning. Keep the deprecated cleanup/compaction no-ops, with backend-neutral warnings that do not assume automatic server maintenance. Embedding configuration forwarding and stale warning removal are now supplied by #4408 in `main`. Retain the regression that verifies full embedding metadata and warning-free remote creation alongside the diagnostics tests. Validation against the merged `main` revision `bbc4aebe` and Lance 14.0.0-beta.1: - Rebuilt the Python extension with `uv run --extra tests --extra dev maturin develop --extras tests,dev`; all 122 remote Python tests passed. Root Ruff checks and formatting passed using the uv-managed environment. - `pnpm build`, `pnpm lint`, formatting, and `pnpm run docs` passed; all 47 remote Node tests and the focused local vector-index regression passed. - All 583 Rust remote tests and 54 query unit tests passed, along with `cargo check --quiet --features remote --tests --examples`, `cargo clippy --quiet --features remote --tests --examples`, and `cargo fmt --all`. Fixes #4393 <!-- lance-gatekeeper-fix:v1 agent=10bafd337999f4910855c3a9b71e7dcf 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
Threading in CPU-limited containers
LanceDB uses separate pools for compute work and storage I/O. On a container with two visible CPUs, current releases intentionally use one compute worker by default; no manual configuration is needed. If every query logs an I/O core reservation warning on a two-CPU container, upgrade from LanceDB 0.21.1 or earlier.
The two commonly tuned environment variables control different resources:
LANCE_CPU_THREADSoverrides the number of compute workers. One worker is the appropriate setting for a two-CPU container when an explicit override is needed.LANCE_IO_THREADScontrols concurrent storage operations, not reserved CPU cores. Its default can be greater than the number of CPUs because I/O workers spend much of their time waiting for storage.
Keep the defaults unless measurements show that the workload benefits from an override. See the Lance threading model for the current defaults and tuning guidance.
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.