Time travel, rollback, and vacuum

Because chunks are immutable and every commit produces a new manifest, old versions are complete snapshots that already exist. Time travel isn’t a feature bolted on — it’s the storage model refusing to forget.

Reading the past

const past = await db.asOf(new Date(Date.now() - 10 * 60 * 1000)); // or a version number
await past.sql`SELECT COUNT(*) FROM customers`;                    // read-only

asOf snapshots are read-only; writes against them are rejected with a pointer to rollbackTo.

The undo button

await db.rollbackTo(past.version);

Rollback is itself a new commit — non-destructive, atomic, and rollbackable. This is the answer to the scariest failure mode of agent-built software: an agent ran a wrong UPDATE or convinced itself a table needed deleting. Recovery is one line, and it exists because of the architecture rather than in spite of it — a stronger safety story than most managed databases offer at this price.

Guardrail note: the prevention side is UPDATE/DELETE without WHERE requiring an explicit { allowFullTable: true }. Rollback is the cure when prevention wasn’t enough.

Retention

History is kept for 7 days or the last 50 versions, whichever keeps more. In format 1 every commit leaves a history snapshot; in format 3 history is sparse checkpoints plus the log — any retained version is reconstructed by replaying deltas from the nearest base, so asOf and rollbackTo keep per-version granularity in both formats.

Vacuum

await db.vacuum(); // { retainDays: 7, retainVersions: 50 } — whichever keeps more

Vacuum drops history outside retention and deletes chunks referenced by no retained version — including orphans from crashed commits, after a grace period. It’s safe alongside live readers and writers: current data is never touched, because the current manifest’s chunks are always retained by definition.

In format 3, log entries are history too: an entry is dropped only when it’s outside the retention window and no longer needed to replay from the oldest retained checkpoint.