New top story on Hacker News: Ask HN: Has anybody shipped a web app at scale with 1 DB per account?

Ask HN: Has anybody shipped a web app at scale with 1 DB per account?
23 by bradgessler | 28 comments on Hacker News.
A common way of deploying a web application database at scale is to setup a MySQL or Postgres server, create one table for all customers, and have an account_id or owner_if field and let the application code handle security. This makes it easier to run database migrations and upgrade code per customer all at once. I’m curious if anybody has taken the approach of provisioning one database per account? This means you’d have to run migrations per account and keep track of all the migration versions and statuses somewhere. Additionally, if an application has custom fields or columns, the differences would have to be tracked somehow and name space collisions managed. Has anybody done this? Particularly with Rails? What kinda of tools or processes did you learn when you did it? Would you do it again? What are some interesting trade offs between the two approaches?