LeonSGP
57a6cce681
LanceDB serializes Pydantic rows with `model_dump()`, which omits `Field(exclude=True)`, but currently constructs an Arrow schema containing those same fields. Creating a local table therefore fails when an excluded field is non-nullable, including defaulted transient fields and nested models. Filter unconditionally excluded fields when converting model schemas, including nested structs. Skip excluded source/vector fields when deriving embedding configuration so persistent metadata does not refer to absent columns. Keep `field_names()` as model-field reflection. Tests exercise implicit and explicit schemas, synchronous and asynchronous create/add/reopen/readback, nested fields, defaults and default factories, retained fields, and local deterministic embeddings. Excluded values are not persisted; `to_pydantic` restores declared defaults. Conditional exclusion and readback of required excluded fields without defaults are outside this change. Implemented with assistance from gpt-6.1-sol; final diff reviewed locally. Local validation reuses the native extension matching official based864e7198f. The current-main Pydantic module is byte-identical to that base, but current-main native code has not been rebuilt. Slow/S3 tests, remote services, and other operating systems were not validated. Reproducible commands after preparing the documented development environment (relative `.venv` examples are equivalent commands; actual local runs use absolute read-only environments and fresh task-private working directories): ```sh PYTHONPATH=python/python .venv/bin/python -m pytest python/python/tests/test_pydantic_excluded_fields.py -q -p no:cacheprovider PYTHONPATH=python/python .venv/bin/python -m pytest python/python/tests -m 'not slow and not s3_test' -q -rs -p no:cacheprovider PYTHONPATH=python/python .venv/bin/python -m pytest --doctest-modules python/python/lancedb -q --tb=short (cd python && PYTHONPATH=python ../.venv/bin/pyright --pythonpath ../.venv/bin/python) .venv/bin/ruff check . .venv/bin/ruff format --check . .venv/bin/python -m pre_commit run --files python/python/lancedb/pydantic.py python/python/tests/test_pydantic_excluded_fields.py git diff --checkd864e7198fHEAD ``` Final frozen-source results: - EXCLUDE_TARGET_COMPLETE_ORIGINAL_RED: Python 3.11.14, exit 1, 1.900076000019908 seconds, {"failed"=>7}. - EXCLUDE_TARGET_EMBEDDING: Python 3.11.14, exit 0, 1.3686820000002626 seconds, {"passed"=>7}. - EXCLUDE_TARGET313: Python 3.13.11, exit 0, 1.7214069999754429 seconds, {"passed"=>7}. - EXCLUDE_FULL311: Python 3.11.14, exit 0, 217.56785399999353 seconds, {"passed"=>1531, "skipped"=>36, "deselected"=>68, "warnings"=>251}. - EXCLUDE_FULL313: Python 3.13.11, exit 0, 197.93847399999504 seconds, {"passed"=>1528, "skipped"=>37, "deselected"=>68, "warnings"=>251}. - EXCLUDE_DOCTEST313: Python 3.13.11, exit 0, 11.8951390000002 seconds, {"passed"=>71, "skipped"=>6, "warnings"=>2}. - EXCLUDE_PYRIGHT: Python 3.13.11, exit 0, 5.808195000019623 seconds, {"warnings"=>0, "errors"=>0}. - EXCLUDE_PRECOMMIT: Python 3.11.14, exit 0, 0.5624079999979585 seconds, {"passed"=>4, "skipped"=>2}. - EXCLUDE_RUFF_FINAL: Ruff 0.9.9, exit 0, 0.06722099997568876 seconds, {}. - EXCLUDE_FORMAT_FINAL: Ruff 0.9.9, exit 0, 0.033322000002954155 seconds, {"files_formatted"=>157}. - EXCLUDE_SYNTAX: Python 3.11.14, exit 0, 0.031629999983124435 seconds, {"files_compiled"=>2}. - EXCLUDE_DIFF_CHECK: Git, exit 0, 0.024460999993607402 seconds, {}.
LanceDB Python SDK
A Python library for LanceDB.
Installation
pip install lancedb
If no wheel is published for your platform, pip builds lancedb from the source distribution. That build needs a Rust toolchain and protoc (the Protocol Buffers compiler) on your PATH, and can take a while.
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.