Slim wheels

The situation

The default pip install schemadex wheel bundles every backend (postgres, sqlite, mysql, duckdb_backend, bigquery, snowflake, mssql). DuckDB alone weighs ~20 MB statically linked, so the all-backends wheel is heavy.

Ideally we would ship a separate slim wheel and let users opt into backends via extras (pip install schemadex[postgres]). That isn't possible today: maturin produces one wheel per build, and PEP 508 extras can only pull in extra Python dependencies — they can't switch which compiled artifact you get. You can't differentiate wheels by extra without publishing them as separate distributions, and we don't want to fragment the PyPI namespace.

The default wheel will stay heavy on PyPI. Power users who care about size can build a slim wheel from source.

Building a slim wheel from source

The schemadex-py crate exposes a slim feature with no backends and a full feature equivalent to default. Pair --no-default-features with the backends you actually need:

# postgres only
maturin build --release --no-default-features \
  --features schemadex-py/postgres

# postgres + sqlite
maturin build --release --no-default-features \
  --features schemadex-py/postgres,schemadex-py/sqlite

# all backends (same as the default PyPI wheel)
maturin build --release --no-default-features \
  --features schemadex-py/full

Pass --out dist to drop the wheel into dist/ and install it with pip install dist/schemadex-*.whl.

Why the full extra is empty

[project.optional-dependencies]
full = []

This row in pyproject.toml is cosmetic. It exists so users who type pip install schemadex[full] get something rather than a hard error. The default wheel already includes every backend, so the extra resolves to no additional Python deps.