Sunday morning reading - a
@VLDBconf 2026 paper on Lakebase from Databricks .. a very nice overview of the architecture that belongs to the same family as any system that treats object storage as the durable backplane and puts a low-latency cache/log in front of it.
Here are some points on how Lakebase handles durability and failure handling, things that differ so subtly across similar platforms like Aurora ..
• Commit point. Lakebase does not fsync WAL on the Postgres compute node. COMMIT returns when a quorum of safekeepers - typically two of three, in different AZs - has flushed that WAL record to local disk. Pageservers and object storage are not in that handshake.
• What each layer is allowed to lose. Compute can vanish at any time, it holds no durable state. A pageserver is a cache, so losing its NVMe does not drop committed transactions. Durability of recent writes sits on safekeeper disks until those segments are uploaded to object storage.
• The tail window. After SUCCESS, new WAL exists only on the safekeeper quorum. S3 catches up later, tracked by backup LSN. If a quorum of those flushed SK copies is destroyed before that upload, acknowledged writes are gone. That is the window, it is not closed at commit time.
• Compute and pageserver failure. Compute crash, scale-to-zero, and failover are 0 data loss because a new compute attaches to the same log. Pageserver NVMe loss does not drop committed transactions, another pageserver can reconstruct pages from WAL and from layers already in object storage.
• Object storage as the long-term copy, not the commit copy. Once backup LSN has passed a segment, Safekeeper-local WAL can be dropped and history lives in the lake. Branching and Point in time recovery use that LSN-addressable history. They do not move the commit rule: SUCCESS still means quorum disk flush, not an S3 PUT.