Point In Time Recovery Under the Hood in Serverless Postgres

Neon, a serverless Postgres solution, enables Point-In-Time Restore (PITR) by separating storage and compute. PITR is made possible through Write-Ahead Logging (WAL), which records all changes to the database, and base backups, snapshots of the database at specific moments in time. Neon's storage engine consists of Safekeepers for data persistence, Pageservers for multi-tenant storage, and another persistence layer for WAL storage in AWS S3. This design allows Postgres to become a stateless compute instance that can start quickly, making Neon serverless. The Pageservers create image and delta layers to store snapshots of key ranges at specific LSNs, allowing developers to access different timelines through ephemeral branches for Time Travel queries.