Files
lancedb/docs
Wyatt Alt 573de654f7 feat: recompute computed column rows whose inputs changed
refresh_column fills nulls, so once a row has a value nothing revisits
it: an update to one of its inputs, or a definition change, leaves the
computed value stale for good.

This stamps the column's field metadata with the definition it was
computed under and a per-fragment signature of the input storage it was
read from (input data files and overlays; not the deletion file, since
a delete changes no surviving value). A refresh recomputes every live
row of a fragment whose stamp disagrees with the manifest, then records
what it computed from in a second commit after the fill. A compacted
fragment inherits freshness through the Rewrite lineage when every
fragment it was built from was signed, or was appended since the stamp,
never had an input moved, and left its rows of the product unfilled (a
raw append may supply a value; the product's data is the evidence, and
the null fill covers those rows); otherwise it recomputes. A
column declared before the stamps existed keeps the null-fill contract
on its first refresh, which enrolls it as it stood.

The stamp is a metadata-only commit on the computed columns, so a
materialized view's drift check treats it like the fill. The core lives
in `table::freshness` so a remote refresh can share the contract.
2026-09-11 04:26:08 +00:00
..
2026-09-09 15:33:04 +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 examples depend on @lancedb/lancedb at file:../dist, so the package must be built before running the tests. This uses pnpm; see the Typescript contributing guide for the toolchain setup.

pushd nodejs
pnpm install
pnpm build
popd

Then you can run the examples by going to the nodejs/examples directory, which is a separate pnpm package with its own lockfile:

pushd nodejs/examples
pnpm install
pnpm 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
# `pnpm docs` would invoke pnpm's built-in `docs` command, not the script.
pnpm run docs
popd