Simon Willison's Weblog: charles-leifer

cysqlite - a new sqlite driver

2026-02-11T17:34:40+00:00

Charles Leifer has been maintaining pysqlite3 - a fork of the Python standard library's sqlite3 module that makes it much easier to run upgraded SQLite versions - since 2018.

He's been working on a ground-up Cython rewrite called cysqlite for almost as long, but it's finally at a stage where it's ready for people to try out.

The biggest change from the sqlite3 module involves transactions. Charles explains his discomfort with the sqlite3 implementation at length - that library provides two different variants neither of which exactly match the autocommit mechanism in SQLite itself.

I'm particularly excited about the support for custom virtual tables, a feature I'd love to see in sqlite3 itself.

cysqlite provides a Python extension compiled from C, which means it normally wouldn't be available in Pyodide. I set Claude Code on it (here's the prompt) and it built me cysqlite-0.1.4-cp311-cp311-emscripten_3_1_46_wasm32.whl, a 688KB wheel file with a WASM build of the library that can be loaded into Pyodide like this:

import micropip
await micropip.install(
    "https://simonw.github.io/research/cysqlite-wasm-wheel/cysqlite-0.1.4-cp311-cp311-emscripten_3_1_46_wasm32.whl"
)
import cysqlite
print(cysqlite.connect(":memory:").execute(
    "select sqlite_version()"
).fetchone())

(I also learned that wheels like this have to be built for the emscripten version used by that edition of Pyodide - my experimental wheel loads in Pyodide 0.25.1 but fails in 0.27.5 with a Wheel was built with Emscripten v3.1.46 but Pyodide was built with Emscripten v3.1.58 error.)

You can try my wheel in this new Pyodide REPL i had Claude build as a mobile-friendly alternative to Pyodide's own hosted console.

I also had Claude build this demo page that executes the original test suite in the browser and displays the results:

Via lobste.rs

Tags: python, sqlite, charles-leifer, webassembly, pyodide, ai-assisted-programming, claude-code

huey

2019-02-25T19:49:06+00:00

huey

Charles Leifer’s “little task queue for Python”. Similar to Celery, but it’s designed to work with Redis, SQLite or in the parent process using background greenlets. Worth checking out for the really neat design. The project is new to me, but it’s been under active development since 2011 and has a very healthy looking rate of releases.

Tags: python, queues, redis, sqlite, charles-leifer

Compiling SQLite for use with Python Applications

2018-08-15T15:51:28+00:00

Compiling SQLite for use with Python Applications

Charles Leifer’s recent tutorial on how to compile and build the latest SQLite (with window function support) for use from Python via his pysqlite3 library.

Via Have this generate binary wheels with latest amalgamation and ship them to PyPI

Tags: pysqlite, python, sqlite, charles-leifer

coleifer/pysqlite3

2018-08-15T15:15:34+00:00

coleifer/pysqlite3

Now that the pysqlite package is bundled as part of the Python standard library the original open source project is no longer actively maintained, and has not been upgraded for Python 3. Charles Leifer has been working on pysqlite3, a stand-alone package of the module. Crucially, this should enable compiling the latest version of SQLite (via the amalgamation package) without needing to upgrade the version that ships with the operating system.

Tags: pysqlite, python, sqlite, charles-leifer

walrus

2017-11-06T01:14:58+00:00

walrus

Fascinating collection of Python utilities for working with Redis, by Charles Leifer. There are a ton of interesting ideas in here. It starts with Python object wrappers for Redis so you can interact with lists, sets, sorted sets and Redis hashes using Python-like objects. Then it gets really interesting: walrus ships with implementations of autocomplete, rate limiting, a graph engine (using a sorted set hexastore) and an ORM-style models mechanism which manages secondary indexes and even implements basic full-text search.

Tags: python, redis, charles-leifer