Simon Willison’s Weblog

Supercharge the One Person Framework with SQLite: Rails World 2024 (via) Stephen Margheim shares an annotated transcript of the YouTube video of his recent talk at this year's Rails World conference in Toronto.

The Rails community is leaning hard into SQLite right now. Stephen's talk is some of the most effective evangelism I've seen anywhere for SQLite as a production database for web applications, highlighting several new changes in Rails 8:

... there are two additions coming with Rails 8 that merit closer consideration. Because these changes make Rails 8 the first version of Rails (and, as far as I know, the first version of any web framework) that provides a fully production-ready SQLite experience out-of-the-box.

Those changes: Ensure SQLite transaction default to IMMEDIATE mode to avoid "database is locked" errors when a deferred transaction attempts to upgrade itself with a write lock (discussed here previously, and added to Datasette 1.0a14 in August) and SQLite non-GVL-blocking, fair retry interval busy handler - a lower-level change that ensures SQLite's busy handler doesn't hold Ruby's Global VM Lock (the Ruby version of Python's GIL) while a thread is waiting on a SQLite lock.

The rest of the talk makes a passionate and convincing case for SQLite as an option for production deployments, in line with the Rails goal of being a One Person Framework - "a toolkit so powerful that it allows a single individual to create modern applications upon which they might build a competitive business".

Back in April Stephen published SQLite on Rails: The how and why of optimal performance describing some of these challenges in more detail (including the best explanation I've seen anywhere of BEGIN IMMEDIATE TRANSACTION) and promising:

Unfortunately, running SQLite on Rails out-of-the-box isn’t viable today. But, with a bit of tweaking and fine-tuning, you can ship a very performant, resilient Rails application with SQLite. And my personal goal for Rails 8 is to make the out-of-the-box experience fully production-ready.

It looks like he achieved that goal!