lancedb-gatefixer[bot]
920b1e7bbb
Fixes #4379 Remote `table_names` discarded the continuation token after the first root-listing request, silently returning the server's default page of 10 names. Remote `list_tables` also inherited that server default, while local listings had no SDK page limit. Python's synchronous and namespace wrappers still imposed a default limit of 10 names. The namespace adapter also discarded continuation tokens, so an unlimited REST namespace listing could stop at the server's page cap. Follow server-provided root listing tokens until the requested name limit or the end of the listing, preserving `start_after`, cache population, and guards against empty or repeated tokens. The namespace adapter collects every server page, then sorts names and applies the name cursor and total limit: namespace tokens are opaque, and page order need not be name order. Empty tokens end the listing; token cycles return an error. Python sync and namespace `table_names` wrappers now default to `None`, matching the asynchronous and TypeScript APIs. Namespace overrides accept the base connection's optional limit, avoiding import-time signature errors on Python 3.10 and 3.11. Set the `list_tables` default to 100 at the shared connection boundary, including namespaces, and return empty results for a zero limit without sending an invalid server request. Update the SDK documentation to describe these defaults. `list_tables()` is now a paginated call in both modes: callers with more than 100 tables must follow the returned token or supply an explicit larger limit. `table_names()` without a limit returns every name. Namespace table-name calls enumerate the namespace before applying name cursors and limits; use `list_tables()` for paginated access. Validation: - Regression cases reproduce the original root-listing truncation and cover 130 tables, opaque tokens, short pages, explicit limits, `start_after`, and zero limits. - Relevant Rust remote database, connection, and local listing test groups: 175 passed. Namespace adapter tests: 23 passed, including opaque tokens, unordered and empty pages, name cursors, limits, zero requests, and token cycles. - Rebuilt the Python extension; namespace and local/mocked remote listing tests using `uv.lock`: 46 passed on Python 3.10 and 46 passed on Python 3.13. - REST namespace regressions reproduced the truncation before the fix and now return all 12 names from a server capped at 10 per response, for sync/async connections at root and child paths. They also cover unordered pages, name cursors, explicit limits, and zero requests. The exact Python 3.10 import error also reproduced before the optional-signature fix. - TypeScript connection test file: 38 passed; `pnpm build`, `pnpm lint`, and `pnpm run docs` passed. - `cargo check --quiet --features remote --tests --examples` and `cargo clippy --quiet --features remote --tests --examples` passed. - Rust formatting, Python Ruff formatting/lint, and diff whitespace checks passed. <!-- lance-gatekeeper-fix:v1 agent=43f92f1f05ac9ca74229af590945cb88 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.