Comment by kentonv

Cloudflare's Durable Objects puts your Worker and SQLite DB on the same physical server (and lets you easily spawn millions of these pairs around the world).

D1 is a simplified wrapper around DO, but D1 does not put your DB on the same machine. You need to use DO directly to get local DBs.

https://developers.cloudflare.com/durable-objects/

(I am the lead engineer for Cloudflare Workers.)