[motorest]

> My take from reading some docs is that you've got to partition your data properly, likely per-user.

I dont't think your take makes sense. I'll explain why.

Cloudflare's doc on D1's service limits states that paid plans have a hard limit on 50k databases per paid account. That's roomy for sharding, but you still end up with a database service that is hosted in a single data center whose clients are served from one of the >300 data centers, and whose cache misses still require pulling data from the primary region. Hypothetically sharding does buy you less write contention, but even in read-heavy applications you still end up with all >300 data centers having to pull data from the primary region whenever a single worker does a write.