Topic
A technique for reusing a limited set of database connections across requests, reducing per-request overhead and governing load in backend applications.
Cloudflare has made Hyperdrive's MySQL support generally available after 20 bug fixes since the beta. Teams running MySQL behind Workers can now weigh it for production, with query caching as the feature to test hardest.
Reality
Postgres row-level security on a tenant_id column is the right default for most B2B SaaS apps, a dev.to guide argues, at two statements and a policy per table. Its warning is that a policy can look secure in a migration diff and still let one tenant reach another's data.
Reality
Postgres policies do not apply to superusers or table owners, so one Next.js team's isolation pattern turns on which role the app connects as and on a variable set inside each request's transaction.
Reality
A tester on Nile's free tier made two tenants, then ran the same SELECT on a connection that never set nile.tenant_id and got every row back. Nile's docs describe that open read as deliberate, so the guarantee sits in application code.
Reality
After bigger instances and a read replica failed to hold, a scheduling SaaS spent its first week tracing requests and changed no code. The five defects it found were each small enough to have shipped unnoticed.
Reality
Fifty concurrent users need about five MySQL connections in a dev.to worked example, because the quantity to size against is simultaneous queries, and Go opens a connection only when a request asks for one.
Reality