Files
lancedb/docs
lancedb-gatefixer[bot] 105fd73bc6 fix(python): commit streaming worker checkpoints on consumption (#4023)
## Summary

- add `StreamingDataLoader`, which transports worker snapshots with
prefetched batches and commits them to the parent dataset only when the
trainer receives each batch
- preserve exact non-uniform per-split progress and resume lagging
splits without replaying already-consumed rows
- reject stale parent checkpoints after a standard multi-process
`DataLoader` has started, with guidance to use the consumer-aware loader
- document the new public loader and merge non-uniform state across
ranks

## Root cause

PyTorch runs `StreamingDataset.__iter__` in private worker-process
copies, while callers invoke `state_dict()` on the parent dataset.
Sharing producer counters would still be incorrect because DataLoader
prefetch can advance workers beyond batches returned to the trainer.

## Validation

- `uv run --extra tests pytest python/tests/test_elastic_dataloader.py
-q` (154 passed)
- focused non-uniform merge regression (1 passed)
- `uv run --project python --extra tests --extra dev ruff format .`
- `uv run --project python --extra tests --extra dev ruff check .`
- `cd docs && PYTHONPATH=. ../python/.venv/bin/mkdocs build`

Fixes #3967

<!-- lance-gatekeeper-fix:v1 agent=572be272619660b97e87fd5c85188341
generation=1 -->

---------

Co-authored-by: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
Co-authored-by: Xuanwo <github@xuanwo.io>
2026-08-25 04:22:22 +08:00
..

LanceDB Documentation

LanceDB docs are available at docs.lancedb.com.

The SDK docs are built and deployed automatically by Github Actions whenever a commit is pushed to the main branch. So it is possible for the docs to show unreleased features.

Building the docs

Setup

  1. Install LanceDB Python. See setup in Python contributing guide. Run make develop to install the Python package.
  2. Install documentation dependencies. From LanceDB repo root: pip install -r docs/requirements.txt

Preview the docs

cd docs
mkdocs serve

If you want to just generate the HTML files:

PYTHONPATH=. mkdocs build -f docs/mkdocs.yml

If successful, you should see a docs/site directory that you can verify locally.

Adding examples

To make sure examples are correct, we put examples in test files so they can be run as part of our test suites.

You can see the tests are at:

  • Python: python/python/tests/docs
  • Typescript: nodejs/examples/

Checking python examples

cd python
pytest -vv python/tests/docs

Checking typescript examples

The @lancedb/lancedb package must be built before running the tests:

pushd nodejs
npm ci
npm run build
popd

Then you can run the examples by going to the nodejs/examples directory and running the tests like a normal npm package:

pushd nodejs/examples
npm ci
npm test
popd

API documentation

Python

The Python API documentation is organized based on the file docs/src/python/python.md. We manually add entries there so we can control the organization of the reference page. However, this means any new types must be manually added to the file. No additional steps are needed to generate the API documentation.

Typescript

The typescript API documentation is generated from the typescript source code using typedoc.

When new APIs are added, you must manually re-run the typedoc command to update the API documentation. The new files should be checked into the repository.

pushd nodejs
npm run docs
popd