void/db can't start on the D1 primary or carry a bookmark across requests #755

Version

void 1.7.0

Problem

Follow-up to #337, which asked for read replication and per-request sessions.

During a request, db from void/db always starts with withSession('first-unconstrained'), and each request gets a new session. That covers read-your-writes within one request, but not across requests: a write followed by a read in the next request can reach a replica that hasn't caught up.

The D1 guide says to handle this like so:

If another read must start with the latest primary data, use env.DB.withSession('first-primary') from cloudflare:workers.

That's the raw D1 API, and there's no supported way to run Drizzle queries on it:

• createDb() calls withSession('first-unconstrained') itself, so it can't be given a different constraint.
• createPrimaryDb() exists in src/runtime/db.ts, but it's private and only used outside a request.
• Using drizzle() directly needs drizzle-orm as a dependency, and void/db is meant to replace that.

So a read that must be fresh has to become raw SQL with hand-written row types.

This affects common flows:

• A form saves and redirects, and the next page's loader shows the old data.
• A user pays and is sent to a page gated on that payment, and a replica says they haven't paid.
• A webhook looks up a row created by an earlier request and doesn't find it.

Proposal

1. A way to get a Drizzle db that starts on the primary and keeps the app's schema, such as createDb(env.DB, { session: 'first-primary' }) or an exported primaryDb.
2. An opt-in bookmark that carries across requests: Void saves getBookmark() in a cookie when a request ends and starts the next request's session from it, so a user always sees their own writes.

Either one would solve the gated-page case. The first suits individual reads and also covers webhooks, which have no cookie. The second fixes the redirect-after-write case across a whole app.

Prior art

Rails' DatabaseSelector and Laravel's sticky option both send a user's reads to the primary after they write.